US3159897A - Machine for extruding hollow cored concrete sections - Google Patents

Description

D 1964 F. G. ELLIS ETAL 3,159,897

7 MACHINE FOR EXTRUDING HOLLOW CORED CONCRETE SECTIONS Filed July 10, 1961 s Sheets-Sheet 1 lnvzn'roas. FREDRIGK.G.ELLI$. mavm A THORSTEINSON BY E W w THEIR A T TYs Dec. 8, 1964 F. G. ELLIS ETAL 3,159,897

MACHINE FOR EXTRUDING HOLLOW CORED CONCRETE SECTIONS Filed July 10, 1961 3 Sheets-Sheet 2 lnvzm'ons.

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MARVIN .A Tnons'rzmsou THEIR AT T Y'S F. G. ELLIS ETAL 3,159,897

MACHINE FOR EXTRUDING HOLLOW CORED- CONCRETE SECTIONS Dec. 3, 1964 3 Sheets-Sheet 3 Filed July 10, 1961 INVENT on: FREDR GK (5 a l. u s

MARVIN A TH ORSTEINSON THEIR AT TY's United States Patent 3,159,597 MAHINE FUR EXTRUDING HGLLOW CGRED CIINCRETE SECTIUNS Fredrick G. Ellis, 248 Egerton Road, and Marvin A. 'Ihorsteinson, 67 Kingston Row, both of Winnipeg, Manitoba, Canada Filed July It), 1%1, Ser. No. 122,698

11 Claims. (CI. 25-41) Our invention relates to new and useful improvements in machines for extruding hollow cored concrete sections.

Precast concrete floor and roof sections are normally cast in lengths and then fitted together at the site. The conventional and present day precast concrete floor and roof sections are made normally from reinforced concrete and apertured longitudinally. I

It is conventional to pour these sections in a mould containing longitudinally extending flexible cores which are then inflated whereupon the concrete is allowed to cure, the cores are deflated and then Withdrawn therefrom.

Not only is it diflicult to manufacture panels of considerable length but it will be appreciated that the cores and the moulds cannot be reused until suificient curing takes place.

This makes the manufacture of such panels relatively expensive and time consuming and this, together with the limitations of the mould, insofar as length is concerned, makes manufacturing relatively difficult. I

Furthermore the equipment required for the manufacture of such slabs is relatively expensive and necessitates considerable capital investment.

We have overcome all of these disadvantages by providing a longitudinally extending pallet or supporting surface of any desired length, a supporting framework adapted to be self propelled along the supporting surface or pallet, a product forming assembly including a feeding section, a moulding sectionand a trowelling section, together with an auger extending through these sections adapted to force the material from the hopper, to the moulding section and out past the trowelling section thus not only forming the exterior surfaces of the slab butalso forming the longitudinally extending apertures. Further-- more the auger compresses the concrete to the desired density and the reaction of the compressed concrete with the inertia of the finished slab on the supporting surface or pallet self propels or'retrudes the machine continuously along said supporting surface or pallet.

Inasmuch as the machine is relatively simple in construction, we have found that we can manufacture slabs on a continuous basis up to any desired length either reinforced or'not reinforced, simply andeconomically.

The principal object and essence of our invention is therefore to provide a device of the character herewithin described which is adapted to produce a longitudinally extending cored concrete product which, due to the viscosity of the mix used, is self supporting once it has been vibrated and compressed'by the forming action of the machine.

Another object of our invention is to provide a device. of the character herewithin described which permits slabs to be formed in any desired length inasmuch as the finished product can be sawn in situ as soon as it has begun to cure.

Another object of our invention is to provide a device of the character herewithin described in which the panels can be made with parallel sides or sloping sides, the latterextending therethrough depending upon the number of vice of the character herewithin described in which the. density of the finished product can be controlled within limits by increasing or decreasing the frictional resistance of the machine upon the pallet or supporting surface.

A still further object of our invention is to provide a device of the character herewithin described which is relatively simple in construction, economical in manufacture and otherwise particularly well suited to the purpose for which it is designed.

With the foregoing objects in view, and such other objects and advantages as will become apparent to those skilled in the art to which this invention relates .as this specification proceeds, my invention consists essentially in the arrangement andconstruction of parts all as here inafter more particularly described, reference being had to the accompanying drawings in which:

FIGURE 1 is an isometric view of our device with the hopper and product forming assembly removed for clarity; FIGURE 2 is an isometric view of our device showing the hopper, the moulding section, and the trowelling section, in a separated condition for clarity.

FIGURE 3 is an end View, reduced. in scale from FIG- URES l and 2 and showing the drive connection to the three augers.

FIGURE 4 is a fragmentary isometric view of one end of a modified pallet showing the starting bulkhead and also, in phantom, a portion of the finished product.

FIGURE 5 shows a side elevation'of one embodiment of the augers. l

FIGURE 6 shows a side elevation of an alternative embodiment of the-angers.

FIGURE 7 is a fragmentary end view of the auger supporting blocks, showing pallet. a

FIGURE 8 is an isometric view of one type of product which can be manufactured by the device.

FIGURE 9'is an isometric view of an alternative type of product which can bemanufactured by the device.

FIGURE 10 is an'isornetric. fragmentary view showing a reinforcing cage in situ upon the pallet.

FIGURE 11 is a top straightening rollers.

FIGURE 12 is an end view of FIGURE 11.

FIGURE 13 is an isometric view of the core used be-- give an oval aperture within the one above the other with the core of FIGURE 13 in situ.

FIGURE l5 is aside elevation of the machine.

In the drawings like characters of reference inicate corresponding parts in thediiferent figures.

Proceeding therefore to describe our invention in de-' tail, reference should be made to the accompanying drawings in which we have illustrated our device. It is of a planar base 11 and upstanding edge flanges 12.

However, it will be appreciated that, if desired, the device I could be used upon any supportingv surface provided means are present to guide the device along the desired path.

its relation to the supporting.

plan view of the pallet side outwardly facing channels.

These channels are main-.

tained in spaced apart parallel relationship by means of cross members 17 secured thereto. These cross members 17 in turn support a source of power in the form of an electric motor 18 mounted'upon a heavy. duty reduction gear box 19. A belt '20 extends between the electric of FIGURE 2. This product forming assembly, which sprocket, and around the sprockets 42 and 43 alternatively as clearly shown'in FIGURE 3, thus ensuring that all of the augers rotate in the same direction.

Reference to FIGURE will show the preferred construction of our angers which consist of an auger shaft 47 having an auger flight 48 formed thereon.

The portion 49 of the shaft within the feeding section is parallel whereas the portion 50 within the moulding section gradually increases in diameter to the maximum is mounted on the aforementioned longitudinal channels 15, consists'of'a feeding section 22, a moulding section 23, and a'trowelling section 24, it being understood that when the machine is assembled, all three sections are ad- 'upper surfaces 30 of the pallet side flanges 12. The clear.-

ances between the edges 29 and the surfaces 30 are maintained by a'transverse support plate 31 secured to the upper surface of the plate 27 by meansof the vertical struts32. 1 V 7 Upon the underside of the plate 31 we provide resilient spacers 33 which are secured to the plate 31 and to the topflanges-34- of the channel members thus suspendin the moulding section 23 in the desired'position. 1

We also provide a vibrating unit 34 mounted upon the a diameter as indicated by the reference character 51 and provides means in association with the surrounding moulding section, to radially compress the product forming material as it passes therethrough.

It will'also be observed that the diameter of the auger flight is constant but, due to the enlarging of the auger shaft 50, the depth of the auger flight decreases to zero.

Extending beyond the point 51 of the auger shaft, we have provided parallel, cylindrical trowelling mandrels 52 and these trowelling mandrels are adapted to rotate within the trowelling section 24 of the assembly. The diameter of the trowelling mandrel is the same as the diameter of the auger fiight and the depth of the flight therefore decreases to Zero, as aforesaid, at the beginning is within the feeding section of the product forming as plate 31' and this vibrating unit is operated from ajso'urce ofpower (not illustrated) so that vibration is given to g This trowelling plate is secured tothe moulding sec-ii tion 23 by means of loose bolts 32'atta-ching to struts 32f so that it will be maintained in close contact; to the moulding section but will not transmit the vibration therefrom. I have found it desirable that the side plates 36 of the moulding section extend rearwardly of the plate $5 in order to maintain the formed product'in the desired configuration remotely from the source 34 of the packing vibration. j

It will be appreciated that the feeding, mouldingand trowelling sections hereinbefore described cooperate with the planar base 11 of the pallet to form the product. as will hereinafter be described:

Referring back to FIGURE 1, the drive 21 extending from thereduction. gear 'box"19 is supported, within a bearing38 in turn supported upon a bearing box 39 secured to the: aforementioned.longitudinal frame members l5.

Journalled for rotation within the box 39 and a rear bearing plate 49 is a plurality of angers 41. In this particular embodiment three such angers have been provided but it'will' be appreciated that this number can be varied as desired.

The portion of the auger shaft between the bearing box 39 and the. rear bearing plate 40 carries chain sprockets sembly, the tapered portions 49. is within the moulding section, and'the cylindrical mandrels 52 are within the trowelling section. i p

The entire machine, if designed to operate with the aforementioned pallet lit is mounted for longitudinal movement upon the pallet by the provision of rollers or wheels 53 journalled for rotation adjacent the lower sides 54 of the aforementioned channels 15 and these wheels or rollers are adapted to emerge the upper edges 39 of the side flanges 12 of the pallet.

In order tovmaintain the device upon the edges of the. pallet, further rollers or wheels 55 are journalled for rota- 7 tion upon the underside of the channels 15, said wheels wvithin the end of the pallet 10 and is provided with three apertures 66 within the plate 5&3 adapted to be engaged by the ends at of the mandrels52..

The desired mix'of the rightconsiste'ncy and fluidity is fed into the hopper 25 and flows by gravity tobetween the side-plates 2d and into the feeding section of the assembly.

The 'sourceof power is activated thus causing the angers to rotate which feeds the productforwardly towards the moulding section 27 which is being vibrated by the :vi brator 34. L i

7 Due to the tapering of the auger shaft S liat this point, the product is'cornpressed and fluidity is maintained due to the vibrator thus causing same to be packed tightly trowelling section which smooths the side and top of the product and sizes same accurately. It then engages the: bulkhead 5t; hereinbeforedescribed and due to the fact that the angers are continuously forcing material from the hopper rearwardly through the moulding section and 42pand a pair of idler sprockets 43 are journalled' for 7 The shaft 21 is provided. with a drive sprocket 45:

and anfendless chain 46 extends around this drive through the trowelling section, the machine is thus urged away or retruded from the bulkhead thus leaving the product therebehind. The mandrels -52 trowel the innerbores62 of the product fa'shownin FIGURE 8 thus resulting in an accurate smooth continuously produced hollow cored section. As long as material is fed into the hopper 25, it will be appreciated that the. product will 55 Continue to be produced to the limit of the length of the pallet 19.

Due to the relative dryness of the mix used and due to the compressibility induced by the auger and the vibrator, the product is self supporting just as soon as the machine passes thereover and is produced without any voids or weak areas occurring.

If it is desired to form keyways 64, within the sides of the product the necessary beads or dowels 66 can be S- cured to the inner faces of the side plates 36 of the trowelling section.

V The relationship of the side plates 36 of the trowelling section and the side plates 23 of the moulding section decide the relationship of the sides 67 of the product. If these plates are parallel, thenv a product will be formed having sides similar to that shown in FIGURE 8. g

If, however, it is desired to form a product as shown in FXGURE 9 with sloping sides 63, then all that is necessary is to slope the plates 26 and 28 so that the sides of the product will be formed in a similar manner. This particular construction is suitable for vertical erection in ring formation for the manufacture of silos, grain storage bins or other cylindrical structures.

' It is often desirable that products of this nature be reinforced and our device is particularly suited for use with,

conventional reinforcing which is shown in FIGURE 10.

A reinforcing cage 69 is manufactured by the provision of a plurality of steel rods 79 held together by means of stirrups 71 at spaced intervals therealong and secured by welding or the like.

This reinforcing cage is laid first upon the pallet and positioned above the base by the provision of stirrups 72 at convenient positions along the length thereof.

The bearing box 39 is apertured as at 73 on the lower edge thereof to allow the machine to pass over the rods 7% as it moves forwardly.

There is sufficient clearance around the bearing box and other portions of the machine to allow free passage of the machine over the cage 69 so that the material is compacted and formed around the reinforcing cage in position upon the paHet.

FIGURE 6 shows an alternative form of auger construction in which the shaft 47 is parallel throughout its length and the auger flight 48 is of the same depth. In this instance, of course, the trowelling mandrel 52 is secured to the end of the shaft 47 and the vertical shoulder 74 formed between the shaft and the mandrel 52' permits the auger to generate sufficient compression in order to accomplish the necessary pressure to pack the material and to self propel the machine along the pallet.

In both instances, of course, it will be realized that the diameter of the auger flight 48 is constant and that in the embodiment shown in FIGURE 5, although the auger flight disappears at the point 51, this is due to the increase in diameter of the shaft up to the diameter of the trowelling mandrel 52. I

It is necessary to control, within limits, the resistance offered by the machine to movement along the pallet as this of course will control the compressive density of the finished product.

By providing spring loaded adjustable side flange engaging clamps 74 secured to the members 15 forwardly of the machine, we can control the frictional resistance of the machine along the pallet. These spring loaded clamps can be adjusted to give a greater or lesser frictional engagement with side flanges. They also act to clean the flanges prior to the machine passing thereover, a point that is essential to the production of a consistent product.

Also, it is desirable that the side flanges be maintained in a true, parallel position one with the other and in this connection reference should be made to FIGURES 11 and 12.

An extension plate 76 to the side members 15 carries a plurality of rollers 77 journalled upon pins 78 and situated alternately upon each side of the side flanges. These In this instance we provide pairs of augers one upon the other designated 79 in these drawings.

.A stationary spindle 8% is adapted to be secured to the bearing box 39 and extend parallel with the pair of augers, said spindle carrying a stationary transversely situated core block 81 upon the end thereof and between the trowelling mandrels 82 of the two vertically situated augers. The upper and lower surfaces 83 of this core block are concaved as shown in FIGURE 13 so that the mandrels nest therewithin and the width of the core block is substantially similar to the diameter of the mandrels.

From the foregoing it will be appreciated that the FIGURE 5 also shows an alternative addition to the auger in order to facilitate the trowelling action and to ensure the smooth finish is supplied to the bores. We mount a trowelling mandrel extension 35 having a cylindrical configuration similar to the mandrel 52.

This mandrel is shouldered as the inner end thereof as at 86 and is adapted to be journalled within a bearing 87 secured within the end of the mandrel 52.

It will therefore be appreciated that as the mandrel is rotated and withdrawn from the bore of the product, the section may remain stationary due to the bearing 87 thus acting as a smoothing portion and at the same time the bearing 87 isolates the portion 85 from any residual vibration from the vibrator 34' which may be present in the augers.

A further improvement is shown in FIGURE 6 in which the trowelling mandrel 52 is provided with a shaft 88 extending axially therefrom and offset slightly from the,

center line. A rolling mandrel 89 is journalled to this shaft by bearings 99 and therefore rolls in the formed bore 62 of a circumference slightly greater than the circumference of the mandrel 52 thus adding extra compression to the material surrounding the bore. Although this is shown in conjunction with the auger in FIGURE 6 it can, of course, be used with the type of auger shown in FIGURE 5.

Furthermore, the mandrel 85 shown in FIGURE 5 can be added on to the rolling mandrel 89 providing the shaft 88 is recentered at this point so that the mandrel 85 follows the formed bore.

In FIGURE 1, the preferred modification to the mandrel 52 is shown, also to reduce vibration effects from the vibrator to the finished bore 62 of the product.

A spindle'9t} is formed on the end of the mandrel 52 and a rubber block 91 surrounds this spindle and registers against the shoulder 92.

A hollow mandrel 93, shouldered internally at 95, registers against the block 91 and a rubber washer 95 engages over the spindle and against the shoulder 94. A washer and nut 96 engages the screw-threaded end of the spindle 99 andsecures the assembly in place.

The mandrel 93 trowels the finish of the bores 62,

Y but does not transmit vibration thereto.

Reference should neXt be made to FIGURE 7, in which we have shown an arcuate or convexedly curved packing assess? plate 97 secured tothe underside of the plate 27 be-. neath the vibrator. This plate 97- extends rearwardly part way along the length of the plate 27 and converges to a point so that it is triangular when viewed in plan. The edges 93 merge into the planer undersurface' of the plate 27. The vibration of this plate, due to the vibrator, urges the material outwardly and ensures that theupper corners of the product are square. It also prevents cavitation occurring of the upper surface of the product, a situation which tends to occur under certain mixture density conditions, if the plate 2'! is completely planar.

Finally-reference to FIGURES and 7 show the incorporation of semi cylindrical shields secured by one end 106 thereof to the wall ltll of the box 3? and extend alongside one or more of the angers 41 in spaced and parallel relationship thereto.

The upper edges 102 (see FIGURE 5) of these shields, are substantially parallel to the longitudinal axis of the auger for the first part of its length and then this upper edge tapers downwardly to meet the lower edge 103 as shown at 104-.

These shields eliminate some of the side thrust developed by the augers thereby eliminating turbulence around the reinforcing wires 79 of the product forming material. This turbulence has the effect, under certain operating con ditions, of forming voids around the wires and the elimiiation of these voids is desirable. v

Since various modifications can be made in my invention as hereinabove described, and many apparently widely different embodiments of same made within the spirit and scope of the claims without departing from such spirit and scope, it is intended "that all mattercontained in the accompanying specification shall be interpreted as illustrative only and not in a limiting sense.

What we claim as our invention is:

l. A machine for forming hollow cored concrete sections on a longitudinally extending supporting surface, comprising in combination a main frame, said main frame including a pair of spaced and parallel longitudinal members, means to support and guide said main frame along said supporting surface, a source of power mounted on said main frame, a product forming assembly mounted between said longitudinal members, said product forming assembly including a feeding secton, a moulding section, and a trowelling section in line with one another, a. feed hopper mounted on said main frame and leading into said feeding section, at least one auger supported for rotation at one end thereof adjacent said feeding which in conjunction with said moulding section, are

adapted to compress said material radially whereby the reaction of said compressionwvith the inertial of the finished product therebehind, self propels said machine along said supporting surface and away from the prodand a vibrator above said moulding section, a source of power for said vibrator, said vibrator adapted to vibrate said moulding section. i

2. The device according to claim 1 in which said moulding section includes a pair of side plates and a top plate spanning said side plate thereby forming, in conjunction with said supporting surface, a mould box adapted to size the resultant product as it is formed thereby.

3. The device according to claim 1 in which said trowelling section includes a pair of side plates situated between said longitudinal members one adjacent each of said longitudinal members, the position of said side plates determining the relation of the sides of the finished product to one another.

4. The device according to claim 1 which includes two angers one above the other and a stationary core portionmounted on said main frame and extending between said two augers, said core portion including a spindle extending through said feeding section and said moulding section, and a core mounted on the end of said spindle and lying transversely between said trowelling mandrels, the upper and lower faces of said core being concave whereby said trowelling mandrels nest therein, the transverse width of said core being substannot formed by said moulding section thereby drawing said portion gradually increasing in diameter to the diameter of said trowelling mandrel whereby the depth of said auger flight decreases to zero adjacent the area joining said trowelling mandrel and the end of said auger shaft,

tially the same as the diameter of said mandrels thereby forming a vertically situated substantially oval, hollow core in said product.

5. The device according to claim 1 which includes a trowelling mandrel extension journalled upon the end of said trowelling mandrel and having a diameter similar thereto.

6. A machine for extruding hollow cored concrete sections on a longitudinally extending supporting surface, comprising in combination a main frame, said main frame including a pair of spaced and parallel longitudinal members, said supporting surface taking the form of a longitudinally extending pallet including a planar base and upstanding side flange edges upon each side edge of said base substantially at right angles thereto, means to support and guide said main frame along said pallet, said means including a plurality of rollers journalled for rotation on said -rnain frame on the underside thereof and engaging the upper edges of said side flanges, and further rollers also journalled for rotation on the underside of said main frame at right angles to said first mentioned rollers and adapted to engage the vertical sides of said side flanges, 'a source of power mounted on said a main frame, said main frame including a pair of spaced and parallel longitudinal members, a product forming assembly mounted between said longitudinal members, said product forming assembly including a feeding section, a moulding section and a trowelling section in line with one another, a feed hopper mounted on said main frame and leading into said feeding section, at least one auger supported for rotation at one end thereof adjacent said feeding section and extending through said feeding section and said moulding section substantially parallel to said supporting surface and spaced therefrom and lying substantially parallel with the longitudinal axis of 'said machine, said auger beingconnected for rotation 60 to said source of power, and atrowelling section, said auger adapted to convey product forming material from the base of said hopper, through said moulding section and into said trowelling section, and means on said auger, which. in conjunction with said moulding section, are adapted to radially compress said materialwhereby the reaction of said compression with the inertia. of the finished product therebehind, self propels said machine along said supporting surface and away frorn the prod not formed by said moulding section thereby drawing said trowelling section over said formed product, said auger including an anger shaft and an auger flight formed thereon, the outer diameter of said'auger flight being substantially constant, the portion of'said shaft in said feeding section having a substantially constant diameter, said last mentioned means on said shaft including the portion of said shaft in said moulding section, said last mentioned portion gradually increasing in diameter to the diameter of said trowelling mandrel whereby the depth of said auger flight decreases to zero at the area between said trowelling mandrel and the end of said auger shaft, a vibrator above said moulding section, and asource of power for said vibrator, said vibrator adapted to vibrate said moulding section.

7. The device according to claim 6 in which said moulding section includes a pair of side plates and a top plate spanning said side plate thereby forming, in conjunction with said supporting surface, a mould box adapted to size the resultant product as it is formed thereby.

8. The device according to claim 6 in which said trowelling section includes a pair of side plates situated between said longitudinal members one adjacent each of said longitudinal members, the position of said side plates determining the relation of the sides of the finished product to one another.

9. The device according to claim 6 which includes two augers one above the other and a stationary core portion mounted on said main frame and extending between said two augers, said core portion including a spindle extending through said feeding section and said moulding section, and a core mounted on the end of said spindle and lying transversely between said trowelling mandrels, the upper and lower faces of said core being concave whereby said trowelling mandrels nest therein, the transverse width of said core being substantially the same as the diameter of said mandrels thereby forming a vertically situated substantially oval, hollow core in said product.

10. The device according to claim 6 which includes a trowelling mandrel extension journalled upon the end of said trowelling mandrel and having a diameter similar thereto.

11. An auger for use in forming hollow cored concrete sections, said auger including a shaft supported for rotation by one end thereof, and an anger flight formed on said shaft, the diameter of said auger flight being constant, said shaft including a portion adjacent said one end having a constant diameter and an adjacent portion extending from said first mentioned portion in which the diameter increases uniformly to the diameter of said auger flight so that'the depth of said auger flight decreases to zero, and a'trowelling mandrel adjacently forms an extension of said second mentioned portion of said shaft, the diameter of said trowelling mandrel,

being similar to the diameter of said flight.

References Cited in the file of this patent UNITED STATES PATENTS Belgium Nov. 14, 1956

Claims (1)

1. A MACHINE FOR FORMING HOLLOW CORED CONCRETE SECTIONS ON A LONGITUDINALLY EXTENDING SUPPORTING SURFACE, COMPRISING IN COMBINATION A MAIN FRAME, SAID MAIN FRAME INCLUDING A PAIR OF SPACED AND PARALLEL LONGITUDINAL MEMBERS, MEANS TO SUPPORT AND GUIDE SAID MAIN FRAME ALONG SAID SUPPORTING SURFACE, A SOURCE OF POWER MOUNTED ON SAID MAIN FRAME, A PRODUCT FORMING ASSEMBLY MOUNTED BETWEEN SAID LONGITUDINAL MEMBERS, SAID PRODUCT FORMING ASSEMBLY INCLUDING A FEEDING SECTON, A MOULDING SECTION, AND A TROWELLING SECTION IN LINE WITH ONE ANOTHER, A FEED HOPPER MOUNTED ON SAID MAIN FRAME AND LEADING INTO SAID FEEDING SECTION, AT LEAST ONE AUGER SUPPORTED FOR ROTATION AT ONE END THEREOF ADJACENT SAID FEEDING SECTION AND EXTENDING THROUGH SAID FEEDING SECTION AND SAID MOULDING SECTION SUBSTANTIALLY PARALLEL TO SAID SUPPORTING SURFACE AND SPACED THEREFROM AND LYING SUBSTANTIALLY PARALLEL WITH THE LONGITUDINAL AXIS OF SAID MACHINE, SAID AUGER BEING CONNECTED FOR ROTATION TO SAID SOURCE OF POWER, AND A TROWELLING MANDREL ON THE OTHER END OF SAID AUGER WITHIN SAID TROWELLING SECTION, SAID AUGER ADAPTED TO CONVEY PRODUCT FORMING MATERIAL FROM THE BASE OF SAID HOPPER, THROUGH SAID MOULDING SECTION AND INTO SAID TROWELLING SECTION, AND MEANS ON SAID AUGER, WHICH IN CONJUNCTION WITH SAID MOULDING SECTION, ARE ADAPTED TO COMPRESS SAID MATERIAL RADIALLY WHEREBY THE REACTION OF SAID COMPRESSION WITH THE INERTIAL OF THE FINISHED PRODUCT THEREBEHIND, SELF PROPELS SAID MACHINE ALONG SAID SUPPORTING SURFACE AND AWAY FROM THE PRODUCT FORMED BY SAID MOULDING SECTION THEREBY DRAWING SAID TROWELLING SECTION OVER SAID FORMED PRODUCT, SAID AUGER INCLUDING AN AUGER SHAFT AND AN AUGER FLIGHT FORMED THEREON, THE OUTER DIAMETER OF SAID AUGER FLIGHT BEING SUBSTANTIALLY CONSTANT, THE PORTION OF SAID SHAFT IN SAID FEEDING SECTION HAVING A SUBSTANTIALLY CONSTANT DIAMETER, SAID LAST MENTIONED MEANS ON SAID SHAFT INCLUDING THE PORTION OF SAID SHAFT IN SAID MOULDING SECTION, SAID LAST MENTIONED PORTION GRADUALLY INCREASING IN DIAMETER TO THE DIAMETER OF SAID TROWELLING MANDREL WHEREBY THE DEPTH OF SAID AUGER FLIGHT DECREASES TO ZERO ADJACENT THE AREA JOINING SAID TROWELLING MANDREL AND THE END OF SAID AUGER SHAFT, AND A VIBRATOR ABOVE SAID MOULDING SECTION, A SOURCE OF POWER FOR SAID VIBRATOR, SAID VIBRATOR ADAPTED TO VIBRATE SAID MOULDING SECTION.

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