CA1122766A - Method and assembly for forming the bell end of a bell and spigot joint - Google Patents
Method and assembly for forming the bell end of a bell and spigot jointInfo
- Publication number
- CA1122766A CA1122766A CA166,712A CA166712A CA1122766A CA 1122766 A CA1122766 A CA 1122766A CA 166712 A CA166712 A CA 166712A CA 1122766 A CA1122766 A CA 1122766A
- Authority
- CA
- Canada
- Prior art keywords
- core
- pipe section
- gasket
- pipe
- section
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C57/00—Shaping of tube ends, e.g. flanging, belling or closing; Apparatus therefor, e.g. collapsible mandrels
- B29C57/02—Belling or enlarging, e.g. combined with forming a groove
- B29C57/025—Belling or enlarging, e.g. combined with forming a groove combined with the introduction of a sealing ring, e.g. using the sealing element as forming element
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10S277/00—Seal for a joint or juncture
- Y10S277/924—Deformation, material removal, or molding for manufacture of seal
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10S425/00—Plastic article or earthenware shaping or treating: apparatus
- Y10S425/218—Pipe machine: socket forming apparatus
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T29/00—Metal working
- Y10T29/49—Method of mechanical manufacture
- Y10T29/4981—Utilizing transitory attached element or associated separate material
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T29/00—Metal working
- Y10T29/49—Method of mechanical manufacture
- Y10T29/49826—Assembling or joining
- Y10T29/49863—Assembling or joining with prestressing of part
- Y10T29/4987—Elastic joining of parts
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T29/00—Metal working
- Y10T29/49—Method of mechanical manufacture
- Y10T29/49826—Assembling or joining
- Y10T29/49863—Assembling or joining with prestressing of part
- Y10T29/4987—Elastic joining of parts
- Y10T29/49872—Confining elastic part in socket
Abstract
A METHOD AND ASSEMBLY FOR FORMING
THE BELL END OF BELL AND SPIGOT JOINT
Abstract of The Disclosure A method of forming the bell end of a bell and spigot joint connecting two pipes together is disclosed herein and utilizes and elongated mandrel having a circumferential recess and a circumferential ramped surface extending from the recess. A sealing gasket is positioned around the mandrel and within the recess, whereupon a heat deformable pipe, heated to its deformable state, is contoured around the gasket supporting mandrel. In this manner, an inner circumferential groove is formed in the pipe and about the gasket so that the latter is disposed within the groove. After the pipe has cooled, the mandrel is withdrawn therefrom, leaving the gasket disposed within the formed groove. During this withdrawal process at least a portion of the gasket is initially outwardly deformed so that it may be easily removed from the recess formed in the mandrel.
THE BELL END OF BELL AND SPIGOT JOINT
Abstract of The Disclosure A method of forming the bell end of a bell and spigot joint connecting two pipes together is disclosed herein and utilizes and elongated mandrel having a circumferential recess and a circumferential ramped surface extending from the recess. A sealing gasket is positioned around the mandrel and within the recess, whereupon a heat deformable pipe, heated to its deformable state, is contoured around the gasket supporting mandrel. In this manner, an inner circumferential groove is formed in the pipe and about the gasket so that the latter is disposed within the groove. After the pipe has cooled, the mandrel is withdrawn therefrom, leaving the gasket disposed within the formed groove. During this withdrawal process at least a portion of the gasket is initially outwardly deformed so that it may be easily removed from the recess formed in the mandrel.
Description
` ` ~lZ;27~i6 A METHOD AND ASSEMBLY FOR FORMING
The present invention relates generally to the formation of pipe joints and more particularly to a method of and assembly for providing the bell end of a bell and spigot joint.
Heretofore, there have been many suggested methods of seal connecting together two pipes. One such method utilizes a bell and spigot joint which includes a female counterpart member, commonly referred to as the bell end, having an enlarged sleeve defining an inner circumferential groove. An annular sealing gasket and two support or retainer rings positioned on opposite side of the gasket are provided within the groove and co-axial with the pipe. In this manner, the male counterpart member, commonly referred to as the spigot, can be inserted into the bell end such that the gasket provides a seal therebetween.
In one method of forming the ball end shown in the prior art, the gasket or packing ring and two support or retainer rings are positioned around the external surface of an elongated core and a thermoplastic pipe, which has been heated to its deformable state, is positioned concentrically around the core, gasket and support rings and allowed to cool. In this manner, an annular ring defining an inner circumferential groove is formed in the pipe around the gasket and support rings.
Thereafter, the core is separated from the pipe, the gasket and rings remaining within the formed inner circumferential groove.
It has been found that the foregoing method requires -` llZ2766 1 various tolerance limitations which are, in many cases, difficult to maintain. For example, the aforedescribed annular groove is formed while the gasket is positioned around the outermost circumference of the core, that is, the circumference representing the outer diameter of the spigot. Hence, if the outer diameter of the spigot is even slightly less than the outer diameter of the core, the sealing capability of the gasket is lessened.
In a variation of this procedure in an attempt to overcome the problems caused by close tolerance limita-tions, the gasket is replaced with a preliminary filling ring during formation of the annular furrow. After formation, the filling ring is removed and a permanent gasket is inserted in the formed groove. However, with this method the installation of the gasket after formation of the groove is quite difficult and time-consuming. In addition, the groove is not always of a proper design to receive the gasket and/or the gasket is not always located properly within the groove or securely held therein.
There are also various other deficiencies of the prior art which are eliminated by the present invention such as, for example, the inability, heretofore, to properly contour the pipe, once heated, about a cooperating core to form the bell end. Reliable contouring is, of course, important since the outer diameter of the core represents the outer diameter of the spigot of the be~l and spigot joint.
An object of the present invention is to provide an improved method of forming the bell end of a bell and llZ2766 -spigot joint around a mandrel and in one end o a heat deformab]e pipe.
Another object of the present invention is to provide a new and improved mandrel assembly utilized in forming an inner circumferential groove in a heat deformable conduit.
In one particular aspect the present invention provides an assembly for use in forming an inner-circumferential groove in a heat deformable pipe, said assembly comprising: (a) an elongated cyclindrical mandrel adapted for insertion concen-trically within one end of a heat deformable pipe by relativemovement between the mandrel and pipe; (b) said mandrel including about its outer periphery a circumferential recess; (c) a circum-ferential sealing gasket, a circumferential portion of which is located within said recess and a circumferential portion of which is located outside said recess; (d) an annular ramped surface com-prising one circumferential side of said recess and tapering radially outwardly and away from the other side of said recess; and (e) means for guiding said one end of said pipe outwardly of said gasket as said end approaches said gasket during said relative movement.
In another particular aspect the present invention provides an assembly for use in forming the bell end of a bell and spigot joint in one end section of a heat deformable pipe, said assembly comprising: (a) an elongated cylindrical mandrel adapted for insertion concentrically within one end of a heat deformable pipe, said mandrel having a first longitudinal seceion and a second radially larger section joining said first section by a tapering intermediate section, said second larger section in-cluding about its periphery a circumferential recess adapted to receive a ring-shaped seallng gasket and an annular ramped surface tapering radially outwardly and away from said circumferential recess, said ra~ped surface being adpated to radially outwardly ll -3-i ~lZ27~;6 deform said sealing gasket; (b) an annular shoulder positloned around the periphery of said second mandrel section and located to one side of said groove opposite said ramped surface, said shoulder being adapted to engage with a support ring positionable on said mandrel whereby to prevent axial movement of said ring in a direction away from said recess; (c) an end ring positioned concentrically about the second section of said mandrel and located to one side of said shoulder opposite said recess, said end ring including a pipe engaging surface tapering radially inwardly; and (d) a pipe directing ring positioned concentrically about said second section and located adjacent the radially outermost end of said ramped surface, said directing ring including an inclined surface adapted to direct the mandrel receiving end of said pipe radially outwardly.
In another particular aspect the present invention provides an assembly for use in forming an inner-circumferential groove in a heat deformable pipe, said assembly comprising: (a) an elongated mandrel having a predetermined cross-section and adapted for insertion within one end of a heat deEormable pipe of a similarly shaped cross-section by relative movement between said mandrél and pipe; (b) said mandrel including about its periphery a circumferential recess; (c) a circumferential sealing gasket9 a circumferential portion of which is located within said recess and a circumferential portion of which is located outside said recess; (d) a circumferential ramped surface comprising one circumferential side of said recess and tapering outwardly and away from the other side of said circumferential recess; and (e) means for guiding said one end of said pipe outwardly of said gasket as said end approaches said gasket during said relative movement.
In another particular aspect the present invention provides an assembly for use in forming an inner-circumferential il/' -3a-1 ' ,~, llZ;~766 groove having retainable forming means disposed therein in a heat deformable pipe section, said assembly comprising: (a) a core having a predetermined outer surface configuration including a circumferential recess about its periphery, said core being adapted for insertion concentrically within one end of a heat deformable pipe by relative movement between said core and pipe;
(b) a retainable forming means at least including a circumferential sealing gasket positioned around said core so that a circumferential portion of said gasket is disposed in said recess and a circumfer-ential portion of said gasket is located outside of said recess and so that the combined outer surface configuration of said core and said retainable forming means is similar to the inner surface configuration desired to be formed in said pipe section; (c) means for guid$ng said one end of said pipe outwardly of said gasket as said end approaches said gasket during said relative movement; (d) means for outwardly deforming said gasket from said supported position during initial relative longitudinal movement of said positioned gasket and core whereby to aid in removing said gasket from said recess.
In another particular aspect the present invention provides an assembly for forming an inner circumferential groove having a circumferential retainable forming means disposed therein in a heat deformable pipe section, said assembly comprising: (a) a core section having a predetermined outer surface configuration and being adapted for insertion concentrically within one end of a heat deformable pipe; (b) circumferential retainable forming means at least including a circumferential sealing gasket; (c) means for supporting said circumferential retainable forming means including said gasket in alignment with said core section such that in the supported position of the gasket the innermost periphery of said gasket is disposed inwardly of the outer surface config-uration of said core section at all points along the inner periphery 3b-1~ ' llZZ766 of the gasket and circumFerential portion of said gasket extends outwardly of said outer surface configuration of said core section and such that the combined outer surface configuration of said core section and said retainable forming means is similar to the inner surface conEiguration desired to be formed in said pipe section; (d) means for guiding said one end of said pipe outwardly of said gasket as said end approaches said gasket during relative movement; and (e) means for outwardly deforming said gasket from said supported position as a result of initial relative longitud-inal movement of said gasket and core section during withdrawal ofsaid core section from said pipe section.
In another particular aspect the present invention provides a method of forming an inner-circumferential groove having a sealing gasket disposed therein in a heat deformable pipe section, said method comprising: (a) providing a substantially cylindrical core including a circumferential recess about its periphery; (b) placing an annular sealing gasket around said core ~ so that a circumferential portion of said gasket is disposed in said recess; (c) heating said pipe section to the range of thermo-elastic deformability; (d) positioning said core and sealinggasket into said heated pipe section by relative movement between said core and pipe section so that said pipe section is deformed so as to form an inner-circumferentlal groove in said pipe section and about said gasket; (e) maintaining said core in a stationary position within said pipe section so that said gasket is disposed in said groove at least until the temperature of said pipe section is below said range of thermoelastic deformability; (f) thereafter, by relative movement withdrawing said core from said p;pe section such that said gasket remains disposed within said groove; and (g) during the withdrawal of said core, at least momentarily causing a portion of said gasket to be radially outwardly deformed for removal from said recess.
~ . -3c-~2~766 In another particular aspect the present invention provides a method of forming an inner~circumferential groove in heat deformable pipe section and about a packing rlng so that said packing ring is disposed within said groove, said method comprising: (a) providing a substantially cylindrical core including an annular recess about its outer periphery and an annular ramped surface tapering outwardly from said recess; (b) placing a packing ring around said core so that a circumferential portion of said ring extends radially from said corP; (c) heating said pipe section to the range of thermo-elastic deformability;
(d) positioning said core including said ramped surface and said packing ring into said heated pipe section by relative movement between the core and pipe section so that said pipe section is deformed so as to form an inner-circumferential groove in said pipe section and about said ring; (e) maintaining said core in-cluding said ramped surface and said ring in said pipe section - at least until the temperature of the latter is below said range of thermo-elastic deformability; (f) thereafter axially moving said core and said pipe section including said packing ring by relative movement between said pipe section and core so as to cause said packing ring to move up said ramped surface; and (g) after said ring has moved up said surface, completely separating said pipe section including said ring disposed withi~ said groove from said core such that said packing ring returns to its undeformed state.
In another particular aspect the present invention provides a method of forming an inner-circumferential groove in a thermoplastic pipe section about a packing ring and two formation rings having radially tapering external surfaces so that all three of said rings are disposed within said groove, said method com-prising: (a) providing a substantially cylindrical core including an annular recess about its outer periphery and an axially extending jl/,: -3d-,...... .
~lZZ7fi6 annular surface tapering outwardly from one side of said recess;
(b) placing said packing ring around said core and within said recess so that a circumferential portion of said ring extends radially outwardly from said core; (c) placing said formation rings around said core and on opposite sides of said packing ring so that the external surfaces of said formation .rings taper radially inwardly in an axial direction away from said packing ring; (d) heating said pipe section to the range of thermo-elastic deformability; (e) positioning said core including said rings into said heated pipe section by relative movement between said core and pipe section so that said pipe section is deformed so as to form an inner-circumferential groove in said core and about said rings; (f) maintaining said core including said rings in said pipe section at least until the temperature of the latter is below said range of thermo-elastic deformability; (g) thereafter, axially moving said core and said pipe section including said rings in opposite axial directions by relative movement between said core and pipe section so as to cause said packing ring to move up said ramped surface for deforming at least a portion of the packing ring in a radially outwardly direction; and (h) after radially outwardly deforming sald ring portion, completely separating said pipe section including said rings disposed within said groove from said core such that said packing ring returns to its undeformed 8 tate.
In another particular aspect the present invention provides a method of forming an inner-circumferential groove having retainable forming means disposed therein in a heat deformable pipe section, said method comprising; (a) providing a core having a predetermined outer surface configuration including a circum-ferential recess about its periphery; (b) placing a retainableforming means around said core so that at least a portion of said retainable forming means is disposed in said recess and so that the jl/ -3e-combined outer surface configuration of said core and said retain-able forming means is similar to the inner surface configuration desired to be formed in said pipe section; (c) heating said pipe section to the range of thermo-elastic deformability; (d) moving said heated pipe section over said core and retainable forming means to a predetermined position by relative movement between said pipe section and said core and retainable forming means; (e) deforming said heated pipe section during said relative movement so that, when said pipe section reaches said predetermined position, said pipe section has an internal surface configuration similar to the external configuration of the combined core and retainable forming means wherein said retainable means is at least partially within an inner-circumferential groove formed in said pipe section;
(f) maintaining said core in a stationary position within said pipe section so that said retainable forming means is disposed in said groove at least until the temperature of said pipe section is below said range of thermo-elastic deformability; (g) thereafter, `- by relative movement withdrawing said core from said pipe section such that said retainable means remains disposed within said groove;
and (h) during the withdrawal of said core, at least momentarily causing a portion of said retainable forming means to be radially outwardly deformed for removal from said recess.
In another particular aspect the present invention provides a method of forming an inner-circumferential groove having a circumferential retainable forming means disposed therein in a heat deformable pipe section, said method comprising: (a) providing a core section having a predetermined outer surface configuration;
(b) supporting said circumferential retainable forming means in alignment with said core section such that in this position the inner periphery of said retainable forming means is disposed inwardly of the outer surface configuration of said core section at all polnts along the inner periphery of the forming means and such jl/,; -3f-that the combined outer surface configuration of said core section and said retainable forming means is similar to the inner surface configuration desired to be fornled in said pipe section; (c) heating said pipe section to the range of thermo-elastic deform-ability; (d) moving said heated pipe section over said core and retainable forming means to a predetermined postion by relative movement between said pipe section and said core and retainable forming means; (e) deforming said heated pipe section during said relative movement so that, when said pipe section reaches said predetermined position, said pipe section has an internal surface configuration similar to the external configuration of the combined core and retainable forming means wherein said retainable means is at least partially within an inner-circumferential groove formed in said pipe section; (f) maintaining said core section and forming means in a stationary position within said pipe section sa that said forming means is disposed in said groove at least until the temperature of said pipe section is below said range of thermo-elastic deformability; (g) therafter, by relative movement with-drawing said core section from said pipe section such that said retainable forming means remains disposed within said groove; and (h) during the withdrawal of said core, at least momentarily causing a portion of said retainable forming means to be radially outwardly deformed for removal from its position of alignment with said core section.
In the drawings:
Figure 1 is a cross-sectional view of the bell end of a bell and spigot joint formed in accordance with the present invention;
Figure 2 is a fragmentary view of the bell end of Figure 1 with the spigot inserted therein;
Figure 3 is a perspective view with portlons broken away of a mandrel assembly constructed in accordance with the 3g-J~
` l~ZZ766 present invention and utilized in the formation of the bell end of Figure l; and Figures 4 and 5 are fragmentary views of the mandrel assembly of Figure 3 illustrating the formation of the bell end.
The present invention is directed to a reliable and uncomplicated method of forming the bell end of a bell and spigot joint in one end section of a heat deformable pipe so as to provide an improved seal between the bell end and the spigot of the joint.
A new and improved mandrel assembly is utilized in the formation process. The assembly, in accordance with the present invention, includes a core having a circumferential recess adapted to receive a sealing gasket and means for outwardly deforming the gasket to aid in removing the gasket from the recess which means in the pre-ferred embodiment comprises a circumferential ramped surface tapering outwardly and away from the recess.
jl/ !~ -3h-, ..
r :'~
1~2766 1In accordance with a preferred method of forming the bell end, a gasket is initially positioned around the core and within the circumferential recess so that a portion of the gasket extends substantially inwardly from the outer circumferential surface of the core.
A pair of support or retainer rings may also be placed around the core and on opposite sides of the sealing gasket.
Thereafter, one end section of a heat deformable pipe, heated to within the range of thermoelastic deformability, 10is positioned around the core including the sealing gasket and support rings to form the bell end. The bell end in-cludes an enlarged sleeve having an inner circumferential groove in which gasket and support rings are positioned.
After the bell end has sufficiently cooled, the core is withdrawn such that the gasket and support rings remain disposed within the inner circumferential groove.
During initial withdrawal of the core, the sealing gasket is caused to move up the ramp surface so as to deform radially outwardly. In this manner, the gasket is easily removed from within the circumferential recess provided in the core.
It should be readily apparent that the inner diameter of the enlarged sleeve comprising part of the bell end is slightly larger than the outer diameter of the core and therefore slightly larger than the outer diameter of the spigot. In addition, it should be apparent that the sealing gasket extends a substantial distance radially in-wardly from the inner surface of the enlarged sleeve.
Hence, if the spigot does not fit tightly within the sleeve, 30due, for example, to tolerance limitations, the gasket l~Z2~66 1 nevertheless provides a reliable seal between the two.
Thus, it is not necessary to rely on unreasonable and sometimes impossible tolerance limitations in the formation of the bell end of a bell and spigot joint.
As shown in FIG. 1, a bell end, generally identified by the reference numeral 10 of a bell and spigot joint, formed in accordance with the present invention, is formed from one end section of a pipe constructed of a heat deformable material such as polyvinylchloride and includes an enlarged bell-shaped sleeve 16 which tapers or flares outwardly as indicated in the drawing by reference numeral 14, from a section 12 of a pipe.
While the heat deformable pipe and the enlarged sleeve will be described and illustrated as having a circular cross-section, it is to be understood that other cross--sectional configurations are contemplated.
As illustrated in FIG. 1, the inner diameter of the sleeve 16 is slightly larger than the outer diameter of the pipe section 12 enabling the sleeve 16 to receive a spigot 1~ which has an outside diameter equal to that of the pipe section 12, in a co-axial fashion as shown in FIG. 2. The inside diameter of a free end 19 of the sleeve 16 is preferably further increased in order to facilitate insertion of the spigot. In addition, the enlarged bell shaped sleeve has an outwardly extending ring 20 which defined an inner circumferential channel or groove 22. An annular sealing gasket 24 constructed of, for example, hard rubber is disposed within the groove 22 and extends inwardly a substantial distance beyond the inner surface of the sleeve 16. In this manner, the gasket 24 provides a reliable seal between the spigot 18 and bell end 10 of the joint. If necessary, the gasket 24 may be held in this position by a pair of support rings 26 also positioned within the groove 22 and on opposite sides of the gasket 24.
As shown in FI&. 1, the sealing gasket 24 displays a profile defined by rounded corners 28 positioned within the annular groove 22 and a rounded corner 30 extending inwardly a substantial distance beyond the internal surface of the enlarged bell-shaped sleeve 16. The rounded corners 28 and the rounded corner 30 are joined by concave surface lines. The support rings 26, which are preferably constructed of poly-vinylchloride, display a substantially triangular pro-file and are positioned firmly against the side walls of the annular groove 22 so that their radially inwardly facing surfaces are substantially flush with the inner surface of the enlarged bell-shaped sleeve 16. In addition, surfaces of the support rings 26 adjoining the gasket 24 are slightly indented for firmly receiving and interlocking with the rounded corners 28 of the sealing gasket 24 to aid in holding the latter within the annular groove 22.
In FIG. 2, the bell end 10 is shown engaged with the spigot 18. As illustrated, the spigot 18 is positioned in contact with and concentrically within the enlarged bell-shaped sleeve 16 of the bell end 10. In this manner, the radially inwardly extending circumferential corner 30 of the gasket 24 is compressed or deformed outwardly by the spigot 18 while the remainder of the gasket is held fixed within channel 22. A reliable seal is thereby 112276~i provided between the bell end lO and the spigot 18.
It is to be understood that the present invention is not limited to the sealing gasket described in FIGS. 1 and 2, but rather contemplates any suitable gasket which is capable of deforming in the manner shown in FIG. 2 for providing a reliable seal. In addition, the particular configuration of the support rings 26 will, in large part, depend upon the shape of the gasket.
In FIG. 3, a mandrel assembly, generally identified by the reference numeral 32, is utilized in the formation of the bell end lO, as will be seen hereinafter. The mandrel assembly 32 includes a cylindrical core 34 having a rear core section 36, the diameter of which is slightly smaller than the diameter of the pipe section 12, and an enlarged forward section 38, the diameter of which is slightly larger than the outer diameter of the spigot 18. The rear section 36 and the enlarged forward section 38 of the cylindrical core 34 are co-axially joined to-gether by an intermediate radially tapering section 40.
A circumferential recess 42 formed in the forward core section 38 is adapted to receive a sealing gasket such as the gasket 24. The sealing gasket 24 is adapted to extend radially outward from within the circumferential recess 42 to a diameter in excess of the diameter of the core section 38. The core section 38 also includes an annular ramped surface 44 tapering radially outwardly from the innermost circumferential surface defining recess 42 in the direction of the rear core section 36. As will be described in more detail, the ramped surface 44, in accordance with the present invention, facilitates removal llZ2766 1 of the gasket 24 from the recess 42 during withdrawal of the core 34 from the bell end 10 once the latter is formed.
In order to accurately contour the bell end 10 around the core 34, it may be desirable to apply a radially inward suction between the two. In a pre-ferred embodiment, the core 34 includes a central bore 46 extending from the free end of the enlarged forward core section 38 and terminating in the intermediate radially tapering section 40. A plurality of suction providing air passages or apertures 48 extend radially outwardly from the bore 46 to the surface of the cylindrical core.
While only a few of these air passages are shown, it is to be understood that a large number thereof may be provided throughout the length of the core sections 38 and 40. In this manner, a suction device (not shown) may be applied to the open end of the central bore 46 to provide a vacuum therein. A pair of O-rings 50 and 52 are disposed within annular recesses provided in the core sections 36 and 38 for providing a seal between the core and the bell end 10.
The O-ring 52 is positioned in the annular recess in the core section 38 which is formed in the free end of the core section 38.
The mandrel assembly 32 also includes a third O-ring 54 positioned within an annular recess formed in the core section 38 to the rear of the annular ramped surface 44.
An end ring 56 is positioned concentrically around the free end of the core section 38. The end ring 56 includes a surface 58 which tapers radially inwardly and towards the free end of the core section 38. The end ring 56 may be held in the position in any suitable manner. As 1 will be seen hereinafter, both the O-ring 54 and end ring 56 aid in the formation of bell end 10 around core 34.
In forming the bell end 10 with the mandrel assembly 32 as illustrated in FIG. 4, a sealing gasket such as the gasket 24 is positioned around the core section 38 and within the recess 42. The support rings 26 may also be positioned around the core section 38 so that their surfaces adjacent the gasket 24 engage respective rounded corners 28 of the gasket 24. In this regard, it should be noted that the forward most end of the core section 38 may be of sufficient diameter to form an annular shoulder 60 adapted to engage with the forward most supporting ring 26 for preventing the ring from moving longitudinally forward during the formation of the bell member 10. The shoulder 60 provides further enlargement of the free end 19 of the bell-shaped sleeve 16 of the bell end 10 which, in turn, facilitates insertion of the spigot 18. If desired or necessary, the core sections may be suitably lubricated and/or heated to reduce friction.
After the end section of an appropriately dimensioned heat deformable pipe has been heated to the range of thermo-elastic deformability, which can be provided in any suit-able way, the free end of the heated pipe section is positioned concentrically around the free end of core section 36. The end section is then caused to move for-ward over the surface of the radially tapering section 40 to move over the first support ring 26, as illustrated in FIG. 4 and over the O-ring 54 which aids in enabling the end section to move over the first support ring 26, as illustrated in FIG. 4. This, of course, causes the end _g _ 1~22766 section to deform outwardly and over gasket 24. As the forward movement of the heated pipe section is continued, the free end of the heated pipe section moves past the gasket 24 and is caused to move inwardly by contacting the tapered surface 58 of the end ring 56, as illustrated in FIG. 5. Internal suction and/or externally applied and radially inwardly directed pressure (not illustrated) is then applied to the core 34.
It should be readily apparent from FIG. 5 that the bell end 10 is formed with the inner circumferential groove 22, gasket 24, and support rings 26, disposed therein. Thereafter, the newly formed bell end is allowed to cool to a temperature below the range of thermoelastic deformability by, for example, exposure to ambient temperature or by application of a cooling fluid thereto. Once the bell end has sufficiently cooled, it is separated from the mandrel assembly with the gasket 24 and the support rings 26 remaining within the inner circumferential groove 22 formed within the bell-shaped sleeve 16. During the initial separation, and in accordance with the present invention, the gasket 24 moves up the ramped surface 44 being radially outwardly deformed and thereby easily moves out of the recess 42. During this process, the outer circumferential surface of the gasket 24 is held in place by the groove 22 formed by the ring 20. The possibility of dislocating the gasket during the withdrawal process is thereby minimized.
The heated end section of pipe may be positioned around the mandrel assembly 32 and separated therefrom after formation of the bell end 10 by conventional means l~lZ2766 1 such as an apparatus i.llustrated and described in United States Letters Patent No. 3,520,047 issued to Muhlner et al on July 14, 1970. In this regard, while the heated end section was described as moving onto and over the core 34, it should be readily apparent that the core could be moved into the heated end section or both the mandrel assembly and end sect.ion could be moved simultaneously.
It should be readily apparent from the foregoing that the bell end 10 is formed in an uncomplicated and reliable fashion.
The present invention relates generally to the formation of pipe joints and more particularly to a method of and assembly for providing the bell end of a bell and spigot joint.
Heretofore, there have been many suggested methods of seal connecting together two pipes. One such method utilizes a bell and spigot joint which includes a female counterpart member, commonly referred to as the bell end, having an enlarged sleeve defining an inner circumferential groove. An annular sealing gasket and two support or retainer rings positioned on opposite side of the gasket are provided within the groove and co-axial with the pipe. In this manner, the male counterpart member, commonly referred to as the spigot, can be inserted into the bell end such that the gasket provides a seal therebetween.
In one method of forming the ball end shown in the prior art, the gasket or packing ring and two support or retainer rings are positioned around the external surface of an elongated core and a thermoplastic pipe, which has been heated to its deformable state, is positioned concentrically around the core, gasket and support rings and allowed to cool. In this manner, an annular ring defining an inner circumferential groove is formed in the pipe around the gasket and support rings.
Thereafter, the core is separated from the pipe, the gasket and rings remaining within the formed inner circumferential groove.
It has been found that the foregoing method requires -` llZ2766 1 various tolerance limitations which are, in many cases, difficult to maintain. For example, the aforedescribed annular groove is formed while the gasket is positioned around the outermost circumference of the core, that is, the circumference representing the outer diameter of the spigot. Hence, if the outer diameter of the spigot is even slightly less than the outer diameter of the core, the sealing capability of the gasket is lessened.
In a variation of this procedure in an attempt to overcome the problems caused by close tolerance limita-tions, the gasket is replaced with a preliminary filling ring during formation of the annular furrow. After formation, the filling ring is removed and a permanent gasket is inserted in the formed groove. However, with this method the installation of the gasket after formation of the groove is quite difficult and time-consuming. In addition, the groove is not always of a proper design to receive the gasket and/or the gasket is not always located properly within the groove or securely held therein.
There are also various other deficiencies of the prior art which are eliminated by the present invention such as, for example, the inability, heretofore, to properly contour the pipe, once heated, about a cooperating core to form the bell end. Reliable contouring is, of course, important since the outer diameter of the core represents the outer diameter of the spigot of the be~l and spigot joint.
An object of the present invention is to provide an improved method of forming the bell end of a bell and llZ2766 -spigot joint around a mandrel and in one end o a heat deformab]e pipe.
Another object of the present invention is to provide a new and improved mandrel assembly utilized in forming an inner circumferential groove in a heat deformable conduit.
In one particular aspect the present invention provides an assembly for use in forming an inner-circumferential groove in a heat deformable pipe, said assembly comprising: (a) an elongated cyclindrical mandrel adapted for insertion concen-trically within one end of a heat deformable pipe by relativemovement between the mandrel and pipe; (b) said mandrel including about its outer periphery a circumferential recess; (c) a circum-ferential sealing gasket, a circumferential portion of which is located within said recess and a circumferential portion of which is located outside said recess; (d) an annular ramped surface com-prising one circumferential side of said recess and tapering radially outwardly and away from the other side of said recess; and (e) means for guiding said one end of said pipe outwardly of said gasket as said end approaches said gasket during said relative movement.
In another particular aspect the present invention provides an assembly for use in forming the bell end of a bell and spigot joint in one end section of a heat deformable pipe, said assembly comprising: (a) an elongated cylindrical mandrel adapted for insertion concentrically within one end of a heat deformable pipe, said mandrel having a first longitudinal seceion and a second radially larger section joining said first section by a tapering intermediate section, said second larger section in-cluding about its periphery a circumferential recess adapted to receive a ring-shaped seallng gasket and an annular ramped surface tapering radially outwardly and away from said circumferential recess, said ra~ped surface being adpated to radially outwardly ll -3-i ~lZ27~;6 deform said sealing gasket; (b) an annular shoulder positloned around the periphery of said second mandrel section and located to one side of said groove opposite said ramped surface, said shoulder being adapted to engage with a support ring positionable on said mandrel whereby to prevent axial movement of said ring in a direction away from said recess; (c) an end ring positioned concentrically about the second section of said mandrel and located to one side of said shoulder opposite said recess, said end ring including a pipe engaging surface tapering radially inwardly; and (d) a pipe directing ring positioned concentrically about said second section and located adjacent the radially outermost end of said ramped surface, said directing ring including an inclined surface adapted to direct the mandrel receiving end of said pipe radially outwardly.
In another particular aspect the present invention provides an assembly for use in forming an inner-circumferential groove in a heat deformable pipe, said assembly comprising: (a) an elongated mandrel having a predetermined cross-section and adapted for insertion within one end of a heat deEormable pipe of a similarly shaped cross-section by relative movement between said mandrél and pipe; (b) said mandrel including about its periphery a circumferential recess; (c) a circumferential sealing gasket9 a circumferential portion of which is located within said recess and a circumferential portion of which is located outside said recess; (d) a circumferential ramped surface comprising one circumferential side of said recess and tapering outwardly and away from the other side of said circumferential recess; and (e) means for guiding said one end of said pipe outwardly of said gasket as said end approaches said gasket during said relative movement.
In another particular aspect the present invention provides an assembly for use in forming an inner-circumferential il/' -3a-1 ' ,~, llZ;~766 groove having retainable forming means disposed therein in a heat deformable pipe section, said assembly comprising: (a) a core having a predetermined outer surface configuration including a circumferential recess about its periphery, said core being adapted for insertion concentrically within one end of a heat deformable pipe by relative movement between said core and pipe;
(b) a retainable forming means at least including a circumferential sealing gasket positioned around said core so that a circumferential portion of said gasket is disposed in said recess and a circumfer-ential portion of said gasket is located outside of said recess and so that the combined outer surface configuration of said core and said retainable forming means is similar to the inner surface configuration desired to be formed in said pipe section; (c) means for guid$ng said one end of said pipe outwardly of said gasket as said end approaches said gasket during said relative movement; (d) means for outwardly deforming said gasket from said supported position during initial relative longitudinal movement of said positioned gasket and core whereby to aid in removing said gasket from said recess.
In another particular aspect the present invention provides an assembly for forming an inner circumferential groove having a circumferential retainable forming means disposed therein in a heat deformable pipe section, said assembly comprising: (a) a core section having a predetermined outer surface configuration and being adapted for insertion concentrically within one end of a heat deformable pipe; (b) circumferential retainable forming means at least including a circumferential sealing gasket; (c) means for supporting said circumferential retainable forming means including said gasket in alignment with said core section such that in the supported position of the gasket the innermost periphery of said gasket is disposed inwardly of the outer surface config-uration of said core section at all points along the inner periphery 3b-1~ ' llZZ766 of the gasket and circumFerential portion of said gasket extends outwardly of said outer surface configuration of said core section and such that the combined outer surface configuration of said core section and said retainable forming means is similar to the inner surface conEiguration desired to be formed in said pipe section; (d) means for guiding said one end of said pipe outwardly of said gasket as said end approaches said gasket during relative movement; and (e) means for outwardly deforming said gasket from said supported position as a result of initial relative longitud-inal movement of said gasket and core section during withdrawal ofsaid core section from said pipe section.
In another particular aspect the present invention provides a method of forming an inner-circumferential groove having a sealing gasket disposed therein in a heat deformable pipe section, said method comprising: (a) providing a substantially cylindrical core including a circumferential recess about its periphery; (b) placing an annular sealing gasket around said core ~ so that a circumferential portion of said gasket is disposed in said recess; (c) heating said pipe section to the range of thermo-elastic deformability; (d) positioning said core and sealinggasket into said heated pipe section by relative movement between said core and pipe section so that said pipe section is deformed so as to form an inner-circumferentlal groove in said pipe section and about said gasket; (e) maintaining said core in a stationary position within said pipe section so that said gasket is disposed in said groove at least until the temperature of said pipe section is below said range of thermoelastic deformability; (f) thereafter, by relative movement withdrawing said core from said p;pe section such that said gasket remains disposed within said groove; and (g) during the withdrawal of said core, at least momentarily causing a portion of said gasket to be radially outwardly deformed for removal from said recess.
~ . -3c-~2~766 In another particular aspect the present invention provides a method of forming an inner~circumferential groove in heat deformable pipe section and about a packing rlng so that said packing ring is disposed within said groove, said method comprising: (a) providing a substantially cylindrical core including an annular recess about its outer periphery and an annular ramped surface tapering outwardly from said recess; (b) placing a packing ring around said core so that a circumferential portion of said ring extends radially from said corP; (c) heating said pipe section to the range of thermo-elastic deformability;
(d) positioning said core including said ramped surface and said packing ring into said heated pipe section by relative movement between the core and pipe section so that said pipe section is deformed so as to form an inner-circumferential groove in said pipe section and about said ring; (e) maintaining said core in-cluding said ramped surface and said ring in said pipe section - at least until the temperature of the latter is below said range of thermo-elastic deformability; (f) thereafter axially moving said core and said pipe section including said packing ring by relative movement between said pipe section and core so as to cause said packing ring to move up said ramped surface; and (g) after said ring has moved up said surface, completely separating said pipe section including said ring disposed withi~ said groove from said core such that said packing ring returns to its undeformed state.
In another particular aspect the present invention provides a method of forming an inner-circumferential groove in a thermoplastic pipe section about a packing ring and two formation rings having radially tapering external surfaces so that all three of said rings are disposed within said groove, said method com-prising: (a) providing a substantially cylindrical core including an annular recess about its outer periphery and an axially extending jl/,: -3d-,...... .
~lZZ7fi6 annular surface tapering outwardly from one side of said recess;
(b) placing said packing ring around said core and within said recess so that a circumferential portion of said ring extends radially outwardly from said core; (c) placing said formation rings around said core and on opposite sides of said packing ring so that the external surfaces of said formation .rings taper radially inwardly in an axial direction away from said packing ring; (d) heating said pipe section to the range of thermo-elastic deformability; (e) positioning said core including said rings into said heated pipe section by relative movement between said core and pipe section so that said pipe section is deformed so as to form an inner-circumferential groove in said core and about said rings; (f) maintaining said core including said rings in said pipe section at least until the temperature of the latter is below said range of thermo-elastic deformability; (g) thereafter, axially moving said core and said pipe section including said rings in opposite axial directions by relative movement between said core and pipe section so as to cause said packing ring to move up said ramped surface for deforming at least a portion of the packing ring in a radially outwardly direction; and (h) after radially outwardly deforming sald ring portion, completely separating said pipe section including said rings disposed within said groove from said core such that said packing ring returns to its undeformed 8 tate.
In another particular aspect the present invention provides a method of forming an inner-circumferential groove having retainable forming means disposed therein in a heat deformable pipe section, said method comprising; (a) providing a core having a predetermined outer surface configuration including a circum-ferential recess about its periphery; (b) placing a retainableforming means around said core so that at least a portion of said retainable forming means is disposed in said recess and so that the jl/ -3e-combined outer surface configuration of said core and said retain-able forming means is similar to the inner surface configuration desired to be formed in said pipe section; (c) heating said pipe section to the range of thermo-elastic deformability; (d) moving said heated pipe section over said core and retainable forming means to a predetermined position by relative movement between said pipe section and said core and retainable forming means; (e) deforming said heated pipe section during said relative movement so that, when said pipe section reaches said predetermined position, said pipe section has an internal surface configuration similar to the external configuration of the combined core and retainable forming means wherein said retainable means is at least partially within an inner-circumferential groove formed in said pipe section;
(f) maintaining said core in a stationary position within said pipe section so that said retainable forming means is disposed in said groove at least until the temperature of said pipe section is below said range of thermo-elastic deformability; (g) thereafter, `- by relative movement withdrawing said core from said pipe section such that said retainable means remains disposed within said groove;
and (h) during the withdrawal of said core, at least momentarily causing a portion of said retainable forming means to be radially outwardly deformed for removal from said recess.
In another particular aspect the present invention provides a method of forming an inner-circumferential groove having a circumferential retainable forming means disposed therein in a heat deformable pipe section, said method comprising: (a) providing a core section having a predetermined outer surface configuration;
(b) supporting said circumferential retainable forming means in alignment with said core section such that in this position the inner periphery of said retainable forming means is disposed inwardly of the outer surface configuration of said core section at all polnts along the inner periphery of the forming means and such jl/,; -3f-that the combined outer surface configuration of said core section and said retainable forming means is similar to the inner surface configuration desired to be fornled in said pipe section; (c) heating said pipe section to the range of thermo-elastic deform-ability; (d) moving said heated pipe section over said core and retainable forming means to a predetermined postion by relative movement between said pipe section and said core and retainable forming means; (e) deforming said heated pipe section during said relative movement so that, when said pipe section reaches said predetermined position, said pipe section has an internal surface configuration similar to the external configuration of the combined core and retainable forming means wherein said retainable means is at least partially within an inner-circumferential groove formed in said pipe section; (f) maintaining said core section and forming means in a stationary position within said pipe section sa that said forming means is disposed in said groove at least until the temperature of said pipe section is below said range of thermo-elastic deformability; (g) therafter, by relative movement with-drawing said core section from said pipe section such that said retainable forming means remains disposed within said groove; and (h) during the withdrawal of said core, at least momentarily causing a portion of said retainable forming means to be radially outwardly deformed for removal from its position of alignment with said core section.
In the drawings:
Figure 1 is a cross-sectional view of the bell end of a bell and spigot joint formed in accordance with the present invention;
Figure 2 is a fragmentary view of the bell end of Figure 1 with the spigot inserted therein;
Figure 3 is a perspective view with portlons broken away of a mandrel assembly constructed in accordance with the 3g-J~
` l~ZZ766 present invention and utilized in the formation of the bell end of Figure l; and Figures 4 and 5 are fragmentary views of the mandrel assembly of Figure 3 illustrating the formation of the bell end.
The present invention is directed to a reliable and uncomplicated method of forming the bell end of a bell and spigot joint in one end section of a heat deformable pipe so as to provide an improved seal between the bell end and the spigot of the joint.
A new and improved mandrel assembly is utilized in the formation process. The assembly, in accordance with the present invention, includes a core having a circumferential recess adapted to receive a sealing gasket and means for outwardly deforming the gasket to aid in removing the gasket from the recess which means in the pre-ferred embodiment comprises a circumferential ramped surface tapering outwardly and away from the recess.
jl/ !~ -3h-, ..
r :'~
1~2766 1In accordance with a preferred method of forming the bell end, a gasket is initially positioned around the core and within the circumferential recess so that a portion of the gasket extends substantially inwardly from the outer circumferential surface of the core.
A pair of support or retainer rings may also be placed around the core and on opposite sides of the sealing gasket.
Thereafter, one end section of a heat deformable pipe, heated to within the range of thermoelastic deformability, 10is positioned around the core including the sealing gasket and support rings to form the bell end. The bell end in-cludes an enlarged sleeve having an inner circumferential groove in which gasket and support rings are positioned.
After the bell end has sufficiently cooled, the core is withdrawn such that the gasket and support rings remain disposed within the inner circumferential groove.
During initial withdrawal of the core, the sealing gasket is caused to move up the ramp surface so as to deform radially outwardly. In this manner, the gasket is easily removed from within the circumferential recess provided in the core.
It should be readily apparent that the inner diameter of the enlarged sleeve comprising part of the bell end is slightly larger than the outer diameter of the core and therefore slightly larger than the outer diameter of the spigot. In addition, it should be apparent that the sealing gasket extends a substantial distance radially in-wardly from the inner surface of the enlarged sleeve.
Hence, if the spigot does not fit tightly within the sleeve, 30due, for example, to tolerance limitations, the gasket l~Z2~66 1 nevertheless provides a reliable seal between the two.
Thus, it is not necessary to rely on unreasonable and sometimes impossible tolerance limitations in the formation of the bell end of a bell and spigot joint.
As shown in FIG. 1, a bell end, generally identified by the reference numeral 10 of a bell and spigot joint, formed in accordance with the present invention, is formed from one end section of a pipe constructed of a heat deformable material such as polyvinylchloride and includes an enlarged bell-shaped sleeve 16 which tapers or flares outwardly as indicated in the drawing by reference numeral 14, from a section 12 of a pipe.
While the heat deformable pipe and the enlarged sleeve will be described and illustrated as having a circular cross-section, it is to be understood that other cross--sectional configurations are contemplated.
As illustrated in FIG. 1, the inner diameter of the sleeve 16 is slightly larger than the outer diameter of the pipe section 12 enabling the sleeve 16 to receive a spigot 1~ which has an outside diameter equal to that of the pipe section 12, in a co-axial fashion as shown in FIG. 2. The inside diameter of a free end 19 of the sleeve 16 is preferably further increased in order to facilitate insertion of the spigot. In addition, the enlarged bell shaped sleeve has an outwardly extending ring 20 which defined an inner circumferential channel or groove 22. An annular sealing gasket 24 constructed of, for example, hard rubber is disposed within the groove 22 and extends inwardly a substantial distance beyond the inner surface of the sleeve 16. In this manner, the gasket 24 provides a reliable seal between the spigot 18 and bell end 10 of the joint. If necessary, the gasket 24 may be held in this position by a pair of support rings 26 also positioned within the groove 22 and on opposite sides of the gasket 24.
As shown in FI&. 1, the sealing gasket 24 displays a profile defined by rounded corners 28 positioned within the annular groove 22 and a rounded corner 30 extending inwardly a substantial distance beyond the internal surface of the enlarged bell-shaped sleeve 16. The rounded corners 28 and the rounded corner 30 are joined by concave surface lines. The support rings 26, which are preferably constructed of poly-vinylchloride, display a substantially triangular pro-file and are positioned firmly against the side walls of the annular groove 22 so that their radially inwardly facing surfaces are substantially flush with the inner surface of the enlarged bell-shaped sleeve 16. In addition, surfaces of the support rings 26 adjoining the gasket 24 are slightly indented for firmly receiving and interlocking with the rounded corners 28 of the sealing gasket 24 to aid in holding the latter within the annular groove 22.
In FIG. 2, the bell end 10 is shown engaged with the spigot 18. As illustrated, the spigot 18 is positioned in contact with and concentrically within the enlarged bell-shaped sleeve 16 of the bell end 10. In this manner, the radially inwardly extending circumferential corner 30 of the gasket 24 is compressed or deformed outwardly by the spigot 18 while the remainder of the gasket is held fixed within channel 22. A reliable seal is thereby 112276~i provided between the bell end lO and the spigot 18.
It is to be understood that the present invention is not limited to the sealing gasket described in FIGS. 1 and 2, but rather contemplates any suitable gasket which is capable of deforming in the manner shown in FIG. 2 for providing a reliable seal. In addition, the particular configuration of the support rings 26 will, in large part, depend upon the shape of the gasket.
In FIG. 3, a mandrel assembly, generally identified by the reference numeral 32, is utilized in the formation of the bell end lO, as will be seen hereinafter. The mandrel assembly 32 includes a cylindrical core 34 having a rear core section 36, the diameter of which is slightly smaller than the diameter of the pipe section 12, and an enlarged forward section 38, the diameter of which is slightly larger than the outer diameter of the spigot 18. The rear section 36 and the enlarged forward section 38 of the cylindrical core 34 are co-axially joined to-gether by an intermediate radially tapering section 40.
A circumferential recess 42 formed in the forward core section 38 is adapted to receive a sealing gasket such as the gasket 24. The sealing gasket 24 is adapted to extend radially outward from within the circumferential recess 42 to a diameter in excess of the diameter of the core section 38. The core section 38 also includes an annular ramped surface 44 tapering radially outwardly from the innermost circumferential surface defining recess 42 in the direction of the rear core section 36. As will be described in more detail, the ramped surface 44, in accordance with the present invention, facilitates removal llZ2766 1 of the gasket 24 from the recess 42 during withdrawal of the core 34 from the bell end 10 once the latter is formed.
In order to accurately contour the bell end 10 around the core 34, it may be desirable to apply a radially inward suction between the two. In a pre-ferred embodiment, the core 34 includes a central bore 46 extending from the free end of the enlarged forward core section 38 and terminating in the intermediate radially tapering section 40. A plurality of suction providing air passages or apertures 48 extend radially outwardly from the bore 46 to the surface of the cylindrical core.
While only a few of these air passages are shown, it is to be understood that a large number thereof may be provided throughout the length of the core sections 38 and 40. In this manner, a suction device (not shown) may be applied to the open end of the central bore 46 to provide a vacuum therein. A pair of O-rings 50 and 52 are disposed within annular recesses provided in the core sections 36 and 38 for providing a seal between the core and the bell end 10.
The O-ring 52 is positioned in the annular recess in the core section 38 which is formed in the free end of the core section 38.
The mandrel assembly 32 also includes a third O-ring 54 positioned within an annular recess formed in the core section 38 to the rear of the annular ramped surface 44.
An end ring 56 is positioned concentrically around the free end of the core section 38. The end ring 56 includes a surface 58 which tapers radially inwardly and towards the free end of the core section 38. The end ring 56 may be held in the position in any suitable manner. As 1 will be seen hereinafter, both the O-ring 54 and end ring 56 aid in the formation of bell end 10 around core 34.
In forming the bell end 10 with the mandrel assembly 32 as illustrated in FIG. 4, a sealing gasket such as the gasket 24 is positioned around the core section 38 and within the recess 42. The support rings 26 may also be positioned around the core section 38 so that their surfaces adjacent the gasket 24 engage respective rounded corners 28 of the gasket 24. In this regard, it should be noted that the forward most end of the core section 38 may be of sufficient diameter to form an annular shoulder 60 adapted to engage with the forward most supporting ring 26 for preventing the ring from moving longitudinally forward during the formation of the bell member 10. The shoulder 60 provides further enlargement of the free end 19 of the bell-shaped sleeve 16 of the bell end 10 which, in turn, facilitates insertion of the spigot 18. If desired or necessary, the core sections may be suitably lubricated and/or heated to reduce friction.
After the end section of an appropriately dimensioned heat deformable pipe has been heated to the range of thermo-elastic deformability, which can be provided in any suit-able way, the free end of the heated pipe section is positioned concentrically around the free end of core section 36. The end section is then caused to move for-ward over the surface of the radially tapering section 40 to move over the first support ring 26, as illustrated in FIG. 4 and over the O-ring 54 which aids in enabling the end section to move over the first support ring 26, as illustrated in FIG. 4. This, of course, causes the end _g _ 1~22766 section to deform outwardly and over gasket 24. As the forward movement of the heated pipe section is continued, the free end of the heated pipe section moves past the gasket 24 and is caused to move inwardly by contacting the tapered surface 58 of the end ring 56, as illustrated in FIG. 5. Internal suction and/or externally applied and radially inwardly directed pressure (not illustrated) is then applied to the core 34.
It should be readily apparent from FIG. 5 that the bell end 10 is formed with the inner circumferential groove 22, gasket 24, and support rings 26, disposed therein. Thereafter, the newly formed bell end is allowed to cool to a temperature below the range of thermoelastic deformability by, for example, exposure to ambient temperature or by application of a cooling fluid thereto. Once the bell end has sufficiently cooled, it is separated from the mandrel assembly with the gasket 24 and the support rings 26 remaining within the inner circumferential groove 22 formed within the bell-shaped sleeve 16. During the initial separation, and in accordance with the present invention, the gasket 24 moves up the ramped surface 44 being radially outwardly deformed and thereby easily moves out of the recess 42. During this process, the outer circumferential surface of the gasket 24 is held in place by the groove 22 formed by the ring 20. The possibility of dislocating the gasket during the withdrawal process is thereby minimized.
The heated end section of pipe may be positioned around the mandrel assembly 32 and separated therefrom after formation of the bell end 10 by conventional means l~lZ2766 1 such as an apparatus i.llustrated and described in United States Letters Patent No. 3,520,047 issued to Muhlner et al on July 14, 1970. In this regard, while the heated end section was described as moving onto and over the core 34, it should be readily apparent that the core could be moved into the heated end section or both the mandrel assembly and end sect.ion could be moved simultaneously.
It should be readily apparent from the foregoing that the bell end 10 is formed in an uncomplicated and reliable fashion.
Claims (41)
1. An assembly for use in forming an inner-circumferential groove in a heat deformable pipe, said assembly comprising:
(a) an elongated cylindrical mandrel adapted for insertion concentrically within one end of a heat deformable pipe by relative movement between the mandrel and pipe;
(b) said mandrel including about its outer periphery a circumferential recess;
(c) a circumferential sealing gasket, a circumferential portion of which is located within said recess and a circum-ferential portion of which is located outside said recess;
(d) an annular ramped surface comprising one circum-ferential side of said recess and tapering radially out-wardly and away from the other side of said recess; and (e) means for guiding said one end of said pipe out-wardly of said gasket as said end approaches said gasket during said relative movement.
(a) an elongated cylindrical mandrel adapted for insertion concentrically within one end of a heat deformable pipe by relative movement between the mandrel and pipe;
(b) said mandrel including about its outer periphery a circumferential recess;
(c) a circumferential sealing gasket, a circumferential portion of which is located within said recess and a circum-ferential portion of which is located outside said recess;
(d) an annular ramped surface comprising one circum-ferential side of said recess and tapering radially out-wardly and away from the other side of said recess; and (e) means for guiding said one end of said pipe out-wardly of said gasket as said end approaches said gasket during said relative movement.
2. An assembly according to Claim 1 including an annular shoulder positioned around the periphery of said mandrel and located to one side of said recess opposite said ramped surface, said shoulder being adapted to engage with a support ring positionable on said mandrel whereby to prevent axial movement of said ring in a direction away from said recess.
3. An assembly according to Claim 1 including an end ring positioned concentrically about said mandrel and located to one side of said recess opposite said ramped surface, said end ring including a pipe engaging surface tapering radially inwardly and away from said recess, said pipe engaging surface being adapted to engage with the mandrel receiving end of said pipe for directing said end radially inwardly.
4. An assembly according to Claim 1 including a pipe directing ring having a circumferential surface portion positioned concentrically about said mandrel and located adjacent the radially outermost end of said ramped surface, said surface portion including an inclined surface adapted to direct the mandrel receiving end of said pipe radially outwardly.
5. An assembly for use in forming the bell end of a bell and spigot joint in one end section of a heat deformable pipe, said assembly comprising:
(a) an elongated cylindrical mandrel adapted for insertion concentrically within one end of a heat deformable pipe, said mandrel having a first longitudinal section and a second radially larger section joining said first section by a tapering intermediate section, said second larger section including about its periphery a circumferential recess adapted to receive a ring-shaped sealing gasket and an annular ramped surface tapering radially outwardly and away from said circumferential recess, said ramped surface being adapted to radially outwardly deform said sealing gasket;
(b) an annular shoulder positioned around the periph-ery of said second mandrel section and located to one side of said groove opposite said ramped surface, said shoulder being adapted to engage with a support ring positionable on said mandrel whereby to prevent axial movement of said ring in a direction away from said recess;
(c) an end ring positioned concentrically about the second section of said mandrel and located to one side of said shoulder opposite said recess, said end ring including a pipe engaging surface tapering radially inwardly; and (d) a pipe directing ring positioned concentrically about said second section and located adjacent the radially outermost end of said ramped surface, said directing ring including an inclined surface adapted to direct the mandrel receiving end of said pipe radially outwardly.
(a) an elongated cylindrical mandrel adapted for insertion concentrically within one end of a heat deformable pipe, said mandrel having a first longitudinal section and a second radially larger section joining said first section by a tapering intermediate section, said second larger section including about its periphery a circumferential recess adapted to receive a ring-shaped sealing gasket and an annular ramped surface tapering radially outwardly and away from said circumferential recess, said ramped surface being adapted to radially outwardly deform said sealing gasket;
(b) an annular shoulder positioned around the periph-ery of said second mandrel section and located to one side of said groove opposite said ramped surface, said shoulder being adapted to engage with a support ring positionable on said mandrel whereby to prevent axial movement of said ring in a direction away from said recess;
(c) an end ring positioned concentrically about the second section of said mandrel and located to one side of said shoulder opposite said recess, said end ring including a pipe engaging surface tapering radially inwardly; and (d) a pipe directing ring positioned concentrically about said second section and located adjacent the radially outermost end of said ramped surface, said directing ring including an inclined surface adapted to direct the mandrel receiving end of said pipe radially outwardly.
6. An assembly according to Claim 5 wherein at least the second section of said mandrel is hollow and includes a plurality of passages extending from the internal surface of said second section to the external surface thereof, and wherein said mandrel further includes first and second O-ring receiving grooves defined around its outer periphery, said first O-ring receiving groove being positioned around said first section and said second section.
7. An assembly for use in forming an inner-cir-cumferential groove in a heat deformable pipe, said assembly comprising:
(a) an elongated mandrel having a predetermined cross-section and adapted for insertion within one end of a heat deformable pipe of a similarly shaped cross-section by relative movement between said mandrel and pipe;
(b) said mandrel including about its periphery a circumferential recess;
(c) a circumferential sealing gasket, a circumfer-ential portion of which is located within said recess and a circumferential portion of which is located outside said recess;
(d) a circumferential ramped surface comprising one circumferential side of said recess and tapering outwardly and away from the other side of said circumferential recess;
and (e) means for guiding said one end of said pipe out-wardly of said gasket as said end approaches said gasket during said relative movement.
(a) an elongated mandrel having a predetermined cross-section and adapted for insertion within one end of a heat deformable pipe of a similarly shaped cross-section by relative movement between said mandrel and pipe;
(b) said mandrel including about its periphery a circumferential recess;
(c) a circumferential sealing gasket, a circumfer-ential portion of which is located within said recess and a circumferential portion of which is located outside said recess;
(d) a circumferential ramped surface comprising one circumferential side of said recess and tapering outwardly and away from the other side of said circumferential recess;
and (e) means for guiding said one end of said pipe out-wardly of said gasket as said end approaches said gasket during said relative movement.
8. An assembly for use in forming an inner-circumferential groove having retainable forming means disposed therein in a heat deformable pipe section, said assembly comprising:
(a) a core having a predetermined outer surface configuration including a circumferential recess about its periphery, said core being adapted for insertion concentrically within one end of a heat deformable pipe by relative movement between said core and pipe;
(b) a retainable forming means at least including a circumferential sealing gasket positioned around said core so that a circumferential portion of said gasket is disposed in said recess and a circumferential portion of said gasket is located outside of said recess and so that the combined outer surface configuration of said core and said retainable forming means is similar to the inner surface configuration desired to be formed in said pipe section;
(c) means for guiding said one end of said pipe out-wardly of said gasket as said end approaches said gasket during said relative movement;
(d) means for outwardly deforming said gasket from said supported position during initial relative longitudinal movement of said positioned gasket and core whereby to aid in removing said gasket from said recess.
(a) a core having a predetermined outer surface configuration including a circumferential recess about its periphery, said core being adapted for insertion concentrically within one end of a heat deformable pipe by relative movement between said core and pipe;
(b) a retainable forming means at least including a circumferential sealing gasket positioned around said core so that a circumferential portion of said gasket is disposed in said recess and a circumferential portion of said gasket is located outside of said recess and so that the combined outer surface configuration of said core and said retainable forming means is similar to the inner surface configuration desired to be formed in said pipe section;
(c) means for guiding said one end of said pipe out-wardly of said gasket as said end approaches said gasket during said relative movement;
(d) means for outwardly deforming said gasket from said supported position during initial relative longitudinal movement of said positioned gasket and core whereby to aid in removing said gasket from said recess.
9. An assembly according to Claim 8 wherein the inner cross-sectional configuration of said pipe section is circular.
10. An assembly according to Claim 8 wherein said deforming means includes a circumferential ramped surface around the periphery of said core, said ramped surface comprising one circumferential side of said recess and tapering outwardly from the other circumferential side of said recess.
11. An assembly according to Claim 10 wherein said retainable forming means includes at least one circum-ferential gasket support element.
12. An assembly for forming an inner circum-ferential groove having a circumferential retainable forming means disposed therein in a heat deformable pipe section, said assembly comprising:
(a) a core section having a predetermined outer surface configuration and being adapted for insertion concentrically within one end of a heat deformable pipe;
(b) circumferential retainable forming means at least including a circumferential sealing gasket;
(c) means for supporting said circumferential retainable forming means including said gasket in alignment with said core section such that in the supported position of the gasket the innermost periphery of said gasket is disposed inwardly of the outer surface configuration of said core section at all points along the inner periphery of the gasket and circumferential portion of said gasket extends outwardly of said outer surface configuration of said core section and such that the combined outer surface config-uration of said core section and said retainable forming means is similar to the inner surface configuration desired to be formed in said pipe section;
(d) means for guiding said one end of said pipe outwardly of said gasket as said end approaches said gasket during relative movement; and (e) means for outwardly deforming said gasket from said supported position as a result of initial relative longitudinal movement of said gasket and core section during withdrawal of said core section from said pipe section.
(a) a core section having a predetermined outer surface configuration and being adapted for insertion concentrically within one end of a heat deformable pipe;
(b) circumferential retainable forming means at least including a circumferential sealing gasket;
(c) means for supporting said circumferential retainable forming means including said gasket in alignment with said core section such that in the supported position of the gasket the innermost periphery of said gasket is disposed inwardly of the outer surface configuration of said core section at all points along the inner periphery of the gasket and circumferential portion of said gasket extends outwardly of said outer surface configuration of said core section and such that the combined outer surface config-uration of said core section and said retainable forming means is similar to the inner surface configuration desired to be formed in said pipe section;
(d) means for guiding said one end of said pipe outwardly of said gasket as said end approaches said gasket during relative movement; and (e) means for outwardly deforming said gasket from said supported position as a result of initial relative longitudinal movement of said gasket and core section during withdrawal of said core section from said pipe section.
13. An assembly according to Claim 12 wherein the inner cross-sectional configuration of said pipe section is circular.
14. An assembly according to Claim 12 wherein said supporting means comprises a circumferential recess about the periphery of said core section and wherein said gasket is positioned around said core section so that a circumferential portion of said forming means is disposed in said recess.
15. An assembly according to Claim 14 wherein said deforming means comprises a circumferential ramped surface around the periphery of said core, said ramped surface comprising one circumferential side of said recess and tapering outwardly from the other circumferential side of said recess.
16. An assembly according to Claim 15 wherein said forming means includes at least one circumferential gasket support element.
17. A method of forming an inner-circumferential groove having a sealing gasket disposed therein in a heat deformable pipe section, said method comprising:
(a) providing a substantially cylindrical core including a circumferential recess about its periphery;
(b) placing an annular sealing gasket around said core so that a circumferential portion of said gasket is disposed in said recess;
(c) heating said pipe section to the range of thermo-elastic deformability;
(d) positioning said core and sealing gasket into said heated pipe section by relative movement between said core and pipe section so that said pipe section is deformed so as to form an inner-circumferential groove in said pipe section and about said gasket;
(e) maintaining said core in a stationary position within said pipe section so that said gasket is disposed in said groove at least until the temperature of said pipe section is below said range of thermoplastic deformability;
(f) thereafter, by relative movement withdrawing said core from said pipe section such that said gasket remains disposed within said groove; and (g) during the withdrawal of said core, at least momentarily causing a portion of said gasket to be radially outwardly deformed for removal from said recess.
(a) providing a substantially cylindrical core including a circumferential recess about its periphery;
(b) placing an annular sealing gasket around said core so that a circumferential portion of said gasket is disposed in said recess;
(c) heating said pipe section to the range of thermo-elastic deformability;
(d) positioning said core and sealing gasket into said heated pipe section by relative movement between said core and pipe section so that said pipe section is deformed so as to form an inner-circumferential groove in said pipe section and about said gasket;
(e) maintaining said core in a stationary position within said pipe section so that said gasket is disposed in said groove at least until the temperature of said pipe section is below said range of thermoplastic deformability;
(f) thereafter, by relative movement withdrawing said core from said pipe section such that said gasket remains disposed within said groove; and (g) during the withdrawal of said core, at least momentarily causing a portion of said gasket to be radially outwardly deformed for removal from said recess.
18. A method according to Claim 17 wherein, during the entering of said core into said pipe section, the core receiving end of said pipe section is radially out-wardly deformed by said core before reaching said gasket.
19. A method according to Claim 17 wherein, during the entering of said core into said pipe section, the core receiving end of said pipe section is radially inwardly deformed after passing over said gasket.
20. A method according to Claim 17 including applying internal suction between said pipe section and core at least while said core is maintained in said stationary position so as to aid in the formation of said groove around said gasket.
21. A method according to Claim 17 including the steps of initially placing two formation rings around said core and on opposite sides of said gasket, and wherein said inner-circumferential groove is formed about said gasket and said rings.
22. A method according to Claim 21 wherein, during the entering of said core into said pipe section, the core receiving end of said pipe section is radially out-wardly deformed before reaching said gasket and rings.
23. A method of forming an inner-circumferential groove in a heat deformable pipe section and about a packing ring so that said packing ring is disposed within said groove, said method comprising:
(a) providing a substantially cylindrical core in-cluding an annular recess about its outer periphery and an annular ramped surface tapering outwardly from said recess;
(b) placing a packing ring around said core so that a circumferential portion of said ring extends radially from said core;
(c) heating said pipe section to the range of thermo-elastic deformability;
(d) positioning said core including said ramped surface and said packing ring into said heated pipe section by relative movement between the core and pipe section so that said pipe section is deformed so as to form an inner--circumferential groove in said pipe section and about said ring;
(e) maintaining said core including said ramped surface and said ring in said pipe section at least until the temper-ature of the latter is below said range of thermoelastic deformability;
(f) thereafter axially moving said core and said pipe section including said packing ring by relative movement between said pipe section and core so as to cause said packing ring to move up said ramped surface; and (g) after said ring has moved up said surface, com-pletely separating said pipe section including said ring disposed within said groove from said core such that said packing ring returns to its undeformed state.
(a) providing a substantially cylindrical core in-cluding an annular recess about its outer periphery and an annular ramped surface tapering outwardly from said recess;
(b) placing a packing ring around said core so that a circumferential portion of said ring extends radially from said core;
(c) heating said pipe section to the range of thermo-elastic deformability;
(d) positioning said core including said ramped surface and said packing ring into said heated pipe section by relative movement between the core and pipe section so that said pipe section is deformed so as to form an inner--circumferential groove in said pipe section and about said ring;
(e) maintaining said core including said ramped surface and said ring in said pipe section at least until the temper-ature of the latter is below said range of thermoelastic deformability;
(f) thereafter axially moving said core and said pipe section including said packing ring by relative movement between said pipe section and core so as to cause said packing ring to move up said ramped surface; and (g) after said ring has moved up said surface, com-pletely separating said pipe section including said ring disposed within said groove from said core such that said packing ring returns to its undeformed state.
24. A method according to Claim 23 wherein two additional rings are individually placed around said core on opposite sides of said packing ring and wherein said inner-circumferential groove is formed about all three of said rings.
25. A method according to Claim 23 including forcing one end of the heated pipe section radially inwardly after positioning said core including said ring and deforming means into said pipe section.
26. A method of forming an inner-circumferential groove in a thermoplastic pipe section about a packing ring and two formation rings having radially tapering external surfaces so that all three of said rings are disposed within said groove, said method comprising:
(a) providing a substantially cylindrical core including an annular recess about its outer periphery and an axially extending annular surface tapering outwardly from one side of said recess;
(b) placing said packing ring around said core and within said recess so that a circumferential portion of said ring extends radially outwardly from said core;
(c) placing said formation rings around said core and on opposite sides of said packing ring so that the external surfaces of said formation rings taper radially inwardly in an axial direction away from said packing ring;
(d) heating said pipe section to the range of thermo-elastic deformability;
(e) positioning said core including said rings into said heated pipe section by relative movement between said core and pipe section so that said pipe section is deformed so as to form an inner-circumferential groove in said core and about said rings;
(f) maintaining said core including said rings in said pipe section at least until the temperature of the latter is below said range of thermoplastic deformability;
(g) thereafter, axially moving said core and said pipe section including said rings in opposite axial directions by relative movement between said core and pipe section so as to cause said packing ring to move up said ramped surface for deforming at least a portion of the packing ring in a radially outwardly direction; and (h) after radially outwardly deforming said ring portion, completely separating said pipe section including said rings disposed within said groove from said core such that said packing ring returns to its undeformed state.
(a) providing a substantially cylindrical core including an annular recess about its outer periphery and an axially extending annular surface tapering outwardly from one side of said recess;
(b) placing said packing ring around said core and within said recess so that a circumferential portion of said ring extends radially outwardly from said core;
(c) placing said formation rings around said core and on opposite sides of said packing ring so that the external surfaces of said formation rings taper radially inwardly in an axial direction away from said packing ring;
(d) heating said pipe section to the range of thermo-elastic deformability;
(e) positioning said core including said rings into said heated pipe section by relative movement between said core and pipe section so that said pipe section is deformed so as to form an inner-circumferential groove in said core and about said rings;
(f) maintaining said core including said rings in said pipe section at least until the temperature of the latter is below said range of thermoplastic deformability;
(g) thereafter, axially moving said core and said pipe section including said rings in opposite axial directions by relative movement between said core and pipe section so as to cause said packing ring to move up said ramped surface for deforming at least a portion of the packing ring in a radially outwardly direction; and (h) after radially outwardly deforming said ring portion, completely separating said pipe section including said rings disposed within said groove from said core such that said packing ring returns to its undeformed state.
27. A method of forming an inner-circumferential groove having retainable forming means disposed therein in a heat deformable pipe section, said method comprising:
(a) providing a core having a predetermined outer surface configuration including a circumferential recess about its periphery;
(b) placing a retainable forming means around said core so that at least a portion of said retainable forming means is disposed in said recess and so that the combined outer surface configuration of said core and said retainable forming means is similar to the inner surface configuration desired to be formed in said pipe section;
(c) heating said pipe section to the range of thermo-elastic deformability;
(d) moving said heated pipe section over said core and retainable forming means to a predetermined position by relative movement between said pipe section and said core and retainable forming means;
(e) deforming said heated pipe section during said relative movement so that, when said pipe section reaches said predetermined position, said pipe section has an internal surface configuration similar to the external configuration of the combined core and retainable forming means wherein said retainable means is at least partially within an inner-circumferential groove formed in said pipe section;
(f) maintaining said core in a stationary position within said pipe section so that said retainable forming means is disposed in said groove at least until the tem-perature of said pipe section is below said range of thermo-elastic deformability;
(g) thereafter, by relative movement withdrawing said core from said pipe section such that said retainable means remains disposed within said groove; and (h) during the withdrawal of said core, at least momentarily causing a portion of said retainable forming means to be radially outwardly deformed for removal from said recess.
(a) providing a core having a predetermined outer surface configuration including a circumferential recess about its periphery;
(b) placing a retainable forming means around said core so that at least a portion of said retainable forming means is disposed in said recess and so that the combined outer surface configuration of said core and said retainable forming means is similar to the inner surface configuration desired to be formed in said pipe section;
(c) heating said pipe section to the range of thermo-elastic deformability;
(d) moving said heated pipe section over said core and retainable forming means to a predetermined position by relative movement between said pipe section and said core and retainable forming means;
(e) deforming said heated pipe section during said relative movement so that, when said pipe section reaches said predetermined position, said pipe section has an internal surface configuration similar to the external configuration of the combined core and retainable forming means wherein said retainable means is at least partially within an inner-circumferential groove formed in said pipe section;
(f) maintaining said core in a stationary position within said pipe section so that said retainable forming means is disposed in said groove at least until the tem-perature of said pipe section is below said range of thermo-elastic deformability;
(g) thereafter, by relative movement withdrawing said core from said pipe section such that said retainable means remains disposed within said groove; and (h) during the withdrawal of said core, at least momentarily causing a portion of said retainable forming means to be radially outwardly deformed for removal from said recess.
28. A method according to Claim 27 wherein the inner cross-sectional configuration of said pipe section is circular.
29. A method according to Claim 27 including:
(a) providing said core with a circumferential ramped surface around its periphery, said ramped surface tapering outwardly from said recess, and (b) during the withdrawal of said core, causing at least a portion of said retainable means to move up said ramped surface for removal from said recess.
(a) providing said core with a circumferential ramped surface around its periphery, said ramped surface tapering outwardly from said recess, and (b) during the withdrawal of said core, causing at least a portion of said retainable means to move up said ramped surface for removal from said recess.
30. A method according to Claim 27 wherein said retainable forming means includes a circumferential sealing gasket.
31. A method according to Claim 30 wherein said retainable forming means includes at least one circumfer-entail gasket support element.
32. A method of forming an inner-circumferential groove having a circumferential retainable forming means disposed therein in a heat deformable pipe section, said method comprising:
(a) providing a core section having a predetermined outer surface configuration;
(b) supporting said circumferential retainable forming means in alignment with said core section such that in this position the inner periphery of said retainable forming means is disposed inwardly of the outer surface config-uration of said core section at all points along the inner periphery of the forming means and such that the combined outer surface configuration of said core section and said retainable forming means is similar to the inner surface configuration desired to be formed in said pipe section;
(c) heating said pipe section to the range of thermo-elastic deformability;
(d) moving said heated pipe section over said core and retainable forming means to a predetermined position by relative movement between said pipe section and said core and retainable forming means;
(e) deforming said heated pipe section during said relative movement so that, when said pipe section reaches said predetermined position, said pipe section has an internal surface configuration similar to the external configuration of the combined core and retainable forming means wherein said retainable means is at least partially within an inner-circumferential groove formed in said pipe section;
(f) maintaining said core section and forming means in a stationary position within said pipe section so that said forming means is disposed in said groove at least until the temperature of said pipe section is below said range of thermoplastic deformability;
(g) thereafter, by relative movement withdrawing said core section from said pipe section such that said retainable forming means remains disposed within said groove; and (h) during the withdrawal of said core, at least momen-tarily causing a portion of said retainable forming means to be radially outwardly deformed for removal from its position of alignment with said core section.
(a) providing a core section having a predetermined outer surface configuration;
(b) supporting said circumferential retainable forming means in alignment with said core section such that in this position the inner periphery of said retainable forming means is disposed inwardly of the outer surface config-uration of said core section at all points along the inner periphery of the forming means and such that the combined outer surface configuration of said core section and said retainable forming means is similar to the inner surface configuration desired to be formed in said pipe section;
(c) heating said pipe section to the range of thermo-elastic deformability;
(d) moving said heated pipe section over said core and retainable forming means to a predetermined position by relative movement between said pipe section and said core and retainable forming means;
(e) deforming said heated pipe section during said relative movement so that, when said pipe section reaches said predetermined position, said pipe section has an internal surface configuration similar to the external configuration of the combined core and retainable forming means wherein said retainable means is at least partially within an inner-circumferential groove formed in said pipe section;
(f) maintaining said core section and forming means in a stationary position within said pipe section so that said forming means is disposed in said groove at least until the temperature of said pipe section is below said range of thermoplastic deformability;
(g) thereafter, by relative movement withdrawing said core section from said pipe section such that said retainable forming means remains disposed within said groove; and (h) during the withdrawal of said core, at least momen-tarily causing a portion of said retainable forming means to be radially outwardly deformed for removal from its position of alignment with said core section.
33. A method according to Claim 32 wherein the inner cross-sectional configuration of said pipe section is circular.
34. A method according to Claim 32 including providing said core section with a circumferential recess about its per-iphery and wherein said supporting step includes placing said forming means around said core section so that a circumferential portion of said forming means is disposed in said recess.
35. A method according to Claim 32 wherein said retainable forming means includes a circumferential gasket.
36. A method according to Claim 35 wherein said forming means includes at least one circumferential gasket support element.
37. A method of forming at the end of a heat deformable pipe an inner circumferential groove having a sealing ring posi-tioned therein, which method comprises placing the sealing ring on a substantially cylindrical mandrel which includes a circumfer-ential recess around its periphery so that at least a portion of the sealing ring is positioned in said recess, heating the pipe end to the range of thermoplastic deformability, introducing the mandrel and the sealing ring into the pipe and thereby causing the pipe end to conform to the mandrel and the sealing ring in order to form the circumferential groove around a portion of the sealing ring, cooling the pipe end to the solid state and removing the pipe end from the mandrel such that the sealing ring remains disposed within the groove in the pipe end.
38. The method of Claim 37 in which in introducing said mandrel bearing said sealing ring in said recess into said end portion of said pipe the opening of said pipe end portion is enlarged to prevent the leading edge of said opening pushing said sealing ring out of said recess in front of said edge.
39. A method of Claim 37, in which said forming takes place during the introduction of said mandrel bearing said sealing ring in said recess into said end portion of said pipe.
40. A method of Claim 37 in which said sealing ring is a rubber sealing ring.
41. A method of Claim 37 in which in said introducing of said mandrel into said pipe end portion said mandrel forms a socket in said end portion.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US00240080A US3807027A (en) | 1972-03-31 | 1972-03-31 | Method of forming the bell end of a bell and spigot joint |
| US240,080 | 1972-03-31 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1122766A true CA1122766A (en) | 1982-05-04 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA166,712A Expired CA1122766A (en) | 1972-03-31 | 1973-03-21 | Method and assembly for forming the bell end of a bell and spigot joint |
Country Status (17)
| Country | Link |
|---|---|
| US (1) | US3807027A (en) |
| JP (1) | JPS545428B2 (en) |
| AR (1) | AR197892A1 (en) |
| AT (1) | AT333553B (en) |
| BE (2) | BE797582A (en) |
| BR (1) | BR7302358D0 (en) |
| CA (1) | CA1122766A (en) |
| CH (1) | CH565971A5 (en) |
| DE (1) | DE2316861C3 (en) |
| DK (1) | DK136972B (en) |
| FI (1) | FI52296C (en) |
| FR (1) | FR2178953B1 (en) |
| GB (1) | GB1397474A (en) |
| IT (1) | IT980051B (en) |
| NL (1) | NL160513C (en) |
| NO (1) | NO145086C (en) |
| SE (1) | SE396905B (en) |
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| US7906180B2 (en) * | 2004-02-27 | 2011-03-15 | Molecular Imprints, Inc. | Composition for an etching mask comprising a silicon-containing material |
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| DE102005025460A1 (en) * | 2005-06-02 | 2006-12-07 | Poloplast Gmbh & Co.Kg | Method for producing a pipe end sleeve and bead insert for forming a bead of a Rohrendsteckmuffe |
| CN112873821B (en) * | 2021-01-08 | 2022-11-25 | 康泰塑胶科技集团有限公司 | High-orientation degree PVC-O pipe with steel skeleton rubber ring arranged in socket in advance and forming method thereof |
Family Cites Families (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2329000A (en) * | 1940-07-17 | 1943-09-07 | Johns Manville | Pipe coupling and method of making the same |
| GB852578A (en) * | 1957-02-23 | 1960-10-26 | Edgar Cartlidge | Improvements in and relating to thermoplastic tube |
| DE1172418B (en) * | 1958-07-22 | 1964-06-18 | Mannesmann Ag | Method and device for forming a socket on the end of a pipe made of thermoplastic material |
| US3265410A (en) * | 1963-07-24 | 1966-08-09 | Ct De Rech S De Pont A Monsson | Pipe of synthetic plastic material and coupling including said pipe |
| BE670478A (en) * | 1964-10-02 | 1966-01-31 | ||
| DE1475735A1 (en) * | 1965-08-02 | 1969-08-28 | Anger Kunststoff | Pipe connection for plastic pipes |
| US3538587A (en) * | 1968-03-21 | 1970-11-10 | Automatic Sprinkler Corp | Apparatus for making valves |
| US3553817A (en) * | 1968-04-10 | 1971-01-12 | Stanley M Lallak | Tool for installing resilient seals |
-
1972
- 1972-03-31 US US00240080A patent/US3807027A/en not_active Expired - Lifetime
-
1973
- 1973-03-21 CA CA166,712A patent/CA1122766A/en not_active Expired
- 1973-03-27 GB GB1463573A patent/GB1397474A/en not_active Expired
- 1973-03-29 DK DK172273AA patent/DK136972B/en not_active IP Right Cessation
- 1973-03-29 IT IT49131/73A patent/IT980051B/en active
- 1973-03-30 FI FI730989A patent/FI52296C/en active
- 1973-03-30 SE SE7304521A patent/SE396905B/en unknown
- 1973-03-30 FR FR7311558A patent/FR2178953B1/fr not_active Expired
- 1973-03-30 NO NO1308/73A patent/NO145086C/en unknown
- 1973-03-30 CH CH463973A patent/CH565971A5/xx not_active IP Right Cessation
- 1973-03-30 BE BE129485A patent/BE797582A/en unknown
- 1973-03-30 NL NL7304461.A patent/NL160513C/en active
- 1973-03-31 JP JP3625473A patent/JPS545428B2/ja not_active Expired
- 1973-04-02 BR BR732358A patent/BR7302358D0/en unknown
- 1973-04-02 AT AT289073A patent/AT333553B/en not_active IP Right Cessation
- 1973-04-02 DE DE2316861A patent/DE2316861C3/en not_active Expired
- 1973-04-03 AR AR247343A patent/AR197892A1/en active
- 1973-10-09 BE BE136488A patent/BE805841R/en active
Also Published As
| Publication number | Publication date |
|---|---|
| BE797582A (en) | 1973-10-01 |
| BR7302358D0 (en) | 1974-02-07 |
| FR2178953B1 (en) | 1975-08-22 |
| DE2316861B2 (en) | 1979-02-15 |
| SE396905B (en) | 1977-10-10 |
| NO145086C (en) | 1982-01-13 |
| NO145086B (en) | 1981-10-05 |
| JPS545428B2 (en) | 1979-03-16 |
| DK136972B (en) | 1977-12-27 |
| NL160513C (en) | 1979-11-15 |
| ATA289073A (en) | 1976-03-15 |
| JPS4925513A (en) | 1974-03-07 |
| FI52296C (en) | 1977-08-10 |
| NL7304461A (en) | 1973-10-02 |
| US3807027A (en) | 1974-04-30 |
| DE2316861A1 (en) | 1973-11-08 |
| AT333553B (en) | 1976-11-25 |
| FI52296B (en) | 1977-05-02 |
| CH565971A5 (en) | 1975-08-29 |
| BE805841R (en) | 1974-04-09 |
| FR2178953A1 (en) | 1973-11-16 |
| AR197892A1 (en) | 1974-05-15 |
| DK136972C (en) | 1978-06-05 |
| IT980051B (en) | 1974-09-30 |
| GB1397474A (en) | 1975-06-11 |
| DE2316861C3 (en) | 1979-10-11 |
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