US3407105A - Heat sealed binding - Google Patents

Description

Oct. 22, 1968 H. N. STAATS ET AL HEAT SEALED BINDING 2 Sheets-Sheet 1 Filed June 24, 1965 fl/aee/eazr ATTORNEYS STAATS ET AL 3,407,105

HEAT SEALED BINDING Oct. 22,1968

2 Sheets-Sheet 2 Filed June 24, 1965 ATTORNEYS MW j United States Patent ABSTRACT OF THE DISCLOSURE A method and apparatus for heat-sealing 'binder elements for a multiplicity of perforated sheets and, more particularly, a.novel method of permanently sealing'in a substantially rigid fashion the thermoplastic binder elements composed of abackbone having a plurality of lapping fingers. I

As those skilled in the art of loose-leaf binding materials are aware, one common form of binding element comprises a coiled plastic member having a backbone'with a plurality of curled; transversely directed teeth spirally curved to pass through a number of multiply perforated sheets of paper or'the like and to curve-into underlapping engagement with the backbone. Ordinarily, the plastic materials employed in such binding elements are relatively stiff'ancl readily permanently set into thecurled position by the application of heat. In common practice, the individual binding elements may be precurled prior to assembly with the perforated paper. In such circumstances, the backbone is positioned manually, or by machinery, in a fixed position and the individual fingers or teeth are uncurled for insertion through the perforations of thepaper, with subsequent release into the curled, laping conditions above described. An alternative method of binding with such elements comprises the insertion of the teeth of a generally flat binding element into a stack of perforated'sheets and curling the fingers by the appli-: cation of heat while in this assembled position. In either case, the resultant assembled book provides a backbone extending generally longitudinally of'the edges of the bound sheets and outwardly overlapping-the ends of the transversely extending curled binding finger-s.

' It is, in many cases, desirable that the resilient bindin element "above described be left in-its curledcondition without any locking capability. In such circumstances, sheets may be removed or added to the bound sheets by springing the curled fingers away from the backbone in unison, removing or adding the sheet, and permitting the fingers to snap back into'their curled, overlapping condition adjacent the backbone;

However, in many instances in which such plastic bindings have been employed, it has become very desirable to provide a permanent binding relationship following the assembly of the binding element to the perforated paper. The need for such a permanent binding has, of course, long been recognized, and has been met through avariety of means. For example, it has been suggested that the overlapping fingers "be glued or otherwise adhesively' secured to the backbone after assembly. Alternatively, various means have been advanced for thermally heating the thermoplastic fingers and backbone to weld the ends of the fingers to the backbone. However, while such welding theoretically provides perhaps the best and most permanent closed binding, no trulysatisfactory technique of welding an assembled book has heretofore come to hand.

It has been found in practice that gluing, and/or the application of adhesives often embrittles the binding materials thereby causing deformation or short life span of the binding. Welding techniques heretofore contem- 3,407,105 Patented Oct. 22, 1968 ice 2 plated have required complicated machines not readily usable in small office installations or requiring complicated back-up bar constructions in which a metallic rod or the like is inserted into the backbone longitudinally thereof and must be removed in the same manner following welding operations. I

-In accordance with the principles of the present invention, we have provided a novel method and apparatus of welding over a relatively limited area, the individual fingers with the backbone of the binding element at areas in which the fingers overlap the backbone. The method and apparatus herein contemplated operate to provide a welded construction without the use of any supporting backbone devices or complicated welding machinery. Further, the apparatus of the present invention may operate at a relatively low' over-all temperature. We have found that 'the method and apparatus of the present invention provides a good bond, is easy to use and is operablev at a very rapid manner compared to heretofore known methods.

In accordance with the present invention, one or more heated needle-like probes are pressed against the backbone from the outside surface thereof at an area aligned with the overlapping end of each finger to be secured. The probe is firmly pressed against the backbone which has sutficient resiliency to resist bending away from the probe. The heated probe initially melts a small hole through the backbone at which point the probe contacts the underlying finger, pushes the underlying finger slightly. away from the backbone and proceeds to melt and pass through the finger. Continued application of heat to the probe causes, at this stage of the process, a small area of melted plastic around the probe both at the backbone and at the finger. Withdrawal of the probe permits the finger to push back into resilient contact with the backbone, permitting the melted area around the probe to merge with the melted area of the backbone such that continued withdrawal of the probe and its subsequent complete removal from the backbone provides a merged, coalesced or melted area providing that may, for descriptive purposes, be a spot-Weld. This weld may, if the probe is small enough, comprise a circular dot of coalesced, merged plastic material, or, if the probe is slightly larger, an annulus of merged, welded material surrounding a srriall aperture. In either event, however, a permanent welded bond is provided at each point of probe penetration. In accordance with the present invention, a single probe may be employed with each overlapping finger'area or, alternatively, a plurality of probes may be employed in a large variation of patterns. v

.It is, accordingly, an object of the present invention to provide a new and improved method and apparatus for permanently assembling plastic binding elements to perforated sheets.

Another object of the present invention is to provide a simple method for heat-sealing thin plastic sheets in I surface-butted relationship.

Yet another object of the present invention is to provide amethod and apparatus for automatically permanently assemblying a plastic binding element to a plurality of perforated sheets immediately following assembly of the binding element to the sheets.

A feature of the invention resides in the application of heat for purposes of thermoplastically welding sheet plastic materials byway of a sharp, needle-like probe.

' Yet another feature of the invention resides in the utilization of a plurality of heating probes for the purpose of providing a multi-point weld between the backbone of a plastic binding element and each individual finger mem-- 3 art from a consideration of the attached drawings wherein a preferred embodiment of the invention is shown by way of illustration only and wherein:

FIGURE 1 comprises a generally isometric view of a binding apparatus constructed in accordance with the present invention;

FIGURE 2 is a partial cross-sectional view of a portion of the apparatus shown in FIGURE 1, and taken along the line IIII of FIGURE 1;

FIGURE 3 is a partial cross-sectional view illustrating a second position of the binding element components shown in FIGURE 2;

FIGURE 4 is a generally isometric view of a partial book and book binding bound in accordance with the principles of the present invention;

FIGURE 5 through 11 illustrate diagrammatically and sequentially the steps of welding a pair of thermoplastic sheet members in face-to-face abutting relation by means of a heated probe, with FIGURE 5 illustrating the sheets and probe immediately prior to probe movement, FIG- URE 6 showing the first stage of movement in which the probe penetrates and melts one of the sheets, FIG- URE 7 showing the position of the parts after penetration of the first sheet and partial penetration of the second sheet, FIGURE 8 showing the complete penetration of both sheets of thermoplastic material by the probe, FIGURE 9 illustrating the partial withdrawal of the probe, FIGURE 10 illustrating a still further withdrawal of the probe, and FIGURE 11 illustrating the completed weld.

As shown on the drawings For many years it has been common practice to provide loose-leaf binding for a plurality of apertured sheets in the form of a binding element constructed of sheet plastic having an integral backbone with a plurality of transversely extending fingers thereon positioned for co-operation with the apertures in the sheets. The binding element normally used comprises a preset curled configuration in which the fingers underlap or overlap the backbone in the assembled condition. Apparatus for uncurling the fingers of a backbone for insertion into the apertures of a plurality of sheets have also long been known. For example, the binding machines of Emmer Patent No. 3,603,801, Frederick No. 2,898,613, and Hardy No. 2,908,173, all illustrate apparatus designed to temporarily hold the backbone of a binding element and uncurl all of the fingers thereof simultaneously for insertion through the punched apertures of a plurality of sheets to be bound.

The apparatus of the present invention is constructed and arranged to provide for permanent heat-sealing of a binding element or the like independently of its manner of assembly to the perforated pages of a bound component. However, it is preferred that the sealing construction be applied as a component of a binding device in order to provide a maximum speed and efiiciency of the total binding operation. Accordingly, a conventional binding component of the type generally discussed in the patents above noted, may be employed. Such a device forms a part of FIGURE 1 and includes a base generally indicated at 10 having a surface area 11 upon which the sheets to be bound are placed, a plurality of upstanding teeth 12 and an equal number of uncurling hooks 13 movable in slots 14. In operation in the conventional manner, the plastic binding element generally indicated at 15 is positioned with its backbone 16 behind the teeth 12. The uncurling hooks 13 move longitudinally relative to the teeth 12, either by movement of the teeth or the hooks, or both simultaneously, to position the hooks inside of the individual binder fingers 17. At this point, the hooks 13 are all moved in the direction of the arrow 18 of FIGURE 1, causing an opening of the binding element as indicated in FIGURE 3. In the opened condition of the binding element shown in FIGURE 3, the ends 19 of the binding element fingers 17 may be passed through the apertures 20 of the stacked perforated sheets 21. At this point, the hooks 13 are returned to their positions immediately adjacent the teeth 12, in the position shown in FIGURES l and 2, permiting the ends 19 of the fingers 17 to curl into an underlapped position relative to the backbone 16. In this condition, the bound sheets 21 may be vertically lifted free of the teeth 12 providing a bound booklet.

The bound booklet above described has, as noted, long been known. It is a fully loose-leaf device since utilization of the device for binding the machine will readily permit a subsequent uncoiling of the fingers, in the same manner as the binding was originally uncoiled, to position the fingers in the state shown in FIGURE 3. This, of course, permits the addition or removal of sheets to the stack 21 and subsequent movement of the uncurling hooks back to the base of the teeth 12 returns the booklet to its bound condition. In accordance with the principles of the present invention, however, it is desired in many instances to provide a permanent binding.

As noted above, permanent welding of the fingers of a thermoplastic binding element of the type 15 employed herein has been attempted. No truly satisfactory inexpensive and yet efiicient technique has been found, however, prior to the present invention. The ditficulties have included the difiiculty of applying sufiicient heat to the interface between the backbone and the ends 19 of the fingers 17. In techniques employing externally applied heat, the outside surfaces of the backbone and related components become overheated if sufiicient heat is provided to melt the plastic interfaces above mentioned. The application of sufficient quantities of heat to the weld area is accomplished in a novel manner in accordance with the present invention. This may be clearly understood in principle from a consideration of FIGURES 5 through 11. There, a needle-like probe 25 is provided. This probe is quite small in diameter and, for example, may very satisfactorily comprise a stainless steel needle of .025" diameter. The needle is heated to a temperature in excess of the temperature at which the thermoplastic material melts. For example, when employing polyvinyl chloride binding material having a melting point approximately 200 F., the temperature of the needle is in excess of 200 F.

As shown in FIGURE 5, the backbone 16 overlaps the fingers 19 of a binding element. The backbone 16 may be supported by positioning on the teeth 12 of a binding apparatus, as above described. In such an arrangement the fingers 19 are maintained against the backbone only by their inherent resiliency. The heated probe 25 is first forced against the backbone 16 as illustrated in FIGURE 6. The heat of the probe 25 melts an area of the thermoplastic material immediately thereadjacent, permitting 'entry of the probe into and through the backbone 16. As shown in FIGURE 6, a melted area 16a occurs immediately around the probe 25. The probe 25 is moved, continuously, in the direction of the arrow 26, passing completely through the backbone 16 and against the ends 19 of the fingers 17. This movement initially causes the ends 19 of the fingers 17 to move away from the backbone 16 as shown in FIGURE 7. Since the probe 25 is heated throughout its length, the melted material 16a of the backbone 16 stays in a melted condition while the probe 25 passes completely through the ends 19 of the fingers 17 as shown in FIGURE 8, causing a melted area 19a therein. In FIGURE 9 the probe 25 is moved in a reverse direction in the direction of arrows 27 withdrawing it from the ends 19 of FIGURE 17. This withdrawal motion carries the ends 19 toward the backbone 16 due to the resiliency of the fingers 17 and the tendency of the heated portions 19a to cling to the needle 25. As the probe 25 continues to move in the direction of arrow 27, it is substantially withdrawn from the backbone 16 as illustrated in FIGURE 10 at which time the melted portions 16a and 19a coalesce or merge together forming a welded spot. Lastly, the probe 25 is completely withdrawn from the backbone 16 and finger ends 19 leaving a welded spot 30.,This welded spot, may be solid, or, where the probe is somewhat larger in diameter, the weld 300 may take the form of an annulus with, a slight perforation completely through one or both of the members 16 and 19.

It will be seen from a consideration of the above sequence of events, that heat is supplied for welding purposes over a relatively limited area. ,This requires a relatively nominal amount of heat. However, .heat is applied directlyat an area where welding may occur, i.e., at the nterface between the backbone and the fingers.This minimal' heatrequirement permits relatively rapidcycling which is not available in systems heretofore considered in which large amounts of heat were required for welding purposes.

Apparatus satisfactorily operating to provide the welding operation above'generally discussed, may be seen in FIGURE 1. There, a heated bar 31 is mounted on slide members 32 reciprocally freely slidable in guides 33 carried by fixed end plates 34 which are in turn mounted on the general housing 10. Springs 35 act to bias the bar in the direction of arrow 36, toward the rotational axis of cam shaft 37. The cam shaft 37 is pivotally mounted in bearings 38 in the plates 34 and is rotated by a chain drive 39. Cam shaft 37 carries earns 40 adjustably rigidly secured thereto by screws 41 or any other conventional adjustable, rigid connection means.

The heating bar 31 is preferably insulated from the slides 32 or, alternatively, the slide 32 may be constructed of a nonthermally conductive material, in order to avoid heat losses from the bar 31. The bar 31 may incorporate an internal Calrod heating unit, or the like, of any conventional construction, designed to provide an even heat over the bar 31. The bar 31 carries a plurality of probe mounts 31a rigidly secured thereto in a thermally conductive manner. Each of the mounts 31a carries one or more probes 25. In the embodiment illustrated each of the mounts 31a carries four probes 25 arranged in a diamond pattern designed to provide a diamond pattern weld as illustrated in FIGURE 4 at 30a, 30b, 30c, and 300?.

The cam shaft 37 rotates the cams 40 in a counterclockwise direction, as shown in FIGURE 2. This rotation reciprocates the slides 32, by way of the rotatable cam followers 40a secured thereto by means of mounting blocks 32a and screws 32b. Rotation of the cam causes movement of the slides 32 toward the backbone 16 as shown in FIGURE 2 in a gradual manner, followed by a relatively rapid withdrawal. The cycle is capable of adjustment, of course, and it has been found that an over-all welding cycle of 2 to 2 /2 sec. is satisfactory when employing polyvinyl chloride binding material of approximately .020" thickness and a needle having a diameter of approximately .025", as above mentioned. The cycle is preferably initiated immediately following return of the hooks 13 to the bound position. Accordingly, where the binding apparatus is motorized to provide an automatic continuous cycling binding action, the cam shaft 37 may be directly driven from that motor to provide for a welding action immediately following return of the hooks to the position adjacent the teeth 12 following the binding operation. For example, a one-revolution mechanism may be initiated by means of a pushbutton 50 on the housing 10, to cause relative movement of the fingers 12 and books 13 to open the binding for insertion of perforated sheets. This continuous motion, conventional in the art, continues by movement of the hooks 13 back to their position immediately adjacent the teeth 12. Further movement of the motor drives chain 38 providing the welding cycle above mentioned. At the end of the welding cycle a cam 51 operates a limit switch 52 deenergizing the circuit until pushbutton 50 is again actuated.

It will be observed that variations may readily be accomplished without departing from the scope of the novel concepts of the present invention. We have found it important, however, to permit freedom of the underlying sheet of plastic being welded, or in the embodiment illus. trated the fingers 17, to yield. It is important in the method here employed that the needle or probe 25 provide a melted, coalesced areaat both places 16a and 19a. This pair of coalesced, melted areas merge to provide the weld. It has been found that if both sheets of material are clamped tightly together the merged coalesced area is reduced and a less satisfactory weld is provided. The pattern of welds may, of course, be varied. It has been found that the diamond-shaped weld area illustrated in FIGURE 4, and above discussed, is a particularly efiicient weld configu' ration. This weld configuration is capable of resisting torsional movements of the backbone and is capable of providing a very strong binding weld. In any'event, it is preferred that more than one weld be employed in order to minimize torsional movement between' the welded parts. In view of the fact that such variations in weld configura tion, thermoplastic materials, and the like, may be made, it is our intention that the scope of the present invention be limited solely by that of the hereinafter appended claims.

We claim as our invention:

1. The method of welding a binding element having a backbone with a plurality of longitudinally spaced transverse fingers thereon curled into an underlapped position against the backbone comprising the steps of holding said backbone against transverse movement, forcing heated needle-like probes of a number equal to the number of fingers through said backbone into contact with an underlying finger to melt areas of the backbone and finger around said probe and withdrawing said probes.

2. Apparatus for welding a coiled plastic binding consisting of a backbone having a plurality of preset coiled fingers integral therewith and curled into underlapped relation with the backbone, comprising abutment means for supporting said backbone at points between the fingers against movement in the direction of the fingers, needlelike probe means, means for heating said probe means to a temperature above the melting point of said plastic binding, means moving said probe means against and through said backbone against the abutment means, and means withdrawing said probe means.

3. Apparatus for welding a coiled plastic binding having a backbone with a plurality of preset coiled fingers integral therewith and curled into underlapped contact relation with the backbone, comprising abutment means for supporting said backbone at points between the fingers against movement in the direction of the fingers, needlelike probe means, means for heating said probe means to a temperature above the melting point of said plastic binding, means moving said probe means against and .through said backbone and sequentially against and through at least one of said fingers, and means withdrawing said probe means, said probe means comprising at least one needle-like probe for each finger and being positioned for co-operation with the respective finger.

4. Apparatus for welding a coiled plastic binding having a backbone with a plurality of preset coiled fingers integral therewith and curled into underlapped contact relation with the backbone, comprising abutment means for supporting said backbone at points between the fingers against movement in the direction of the fingers, needlelike probe means, means for heating said probe means to a temperature above the melting point of said plastic binding, means moving said probe against and through said backbone and sequentially against and through at least one of said fingers, and means withdrawing said probe means, said probe means comprising a plurality of needle-like probes for each finger and cooperating with a respective finger to provide a multiple number of welds between each finger and the backbone.

5. Apparatus for welding a coiled plastic binding having a backbone with a plurality of preset coiled fingers integral therewith and curled into underlapped contact relation with the backbone, comprising abutment means for supporting said backbone at points between the fingers against movement in'the direction of the fingers, needlelike probe means, means for heating said probe means to a temperature above the melting point of said plastic binding, means moving said probe means against and through said backbone and sequentially against and through at least one of said fingers, and means withdrawing said probe means, said probe means comprising needle-like probe means comprising a plurality of probes for each finger and formed in a diamond pattern to provide spot-welds in a diamond pattern between each finger and the backbone.

6. The method of welding a binding element having a backbone with a plurality of longitudinally spaced transverse fingers thereon curled into an underlapped holding said backbone against transverse movement, forcing a plurality of heated needle-like probes against and through at least one of said fingers and said backbone to coalesce areas of the backbone and immediately adjacent finger, and withdrawing said probe.

References Cited UNITED STATES PATENTS 2,106,419 1/1938 Anderson 281--21 2,202,097 5/ 1940 Farkas 28l21 2,545,243 3/1951 Rumsey 156-253 2,571,525 10/1951" Blitstein 11-1 2,974,717 3/1961 Lindsay 156-582 position against the backbone comprising the steps of 15 DOUGLAS J. DRUMMOND, Primary Examiner.

Images