US2867846A - Rolling of plastic strips - Google Patents

Description

Jan. 13, 1959 G. A. ROWLEY 120mm; 0F PLASTIC STRIPS 5 Sheets-Sheet 1 Filed Dec. 30, 1950 Inventor By George A. Rowley Afiy Jan. 13, 1959 G. A. ROWLEY ROLLING OF PLASTIC STRIPS 5 Sheets-Sheet 2 Filed Dec. 30, 1950 In venfor By George Rowley mm mm mm Jan. 13, 1959 G. A. ROWLEY 2,367,846

ROLLING 0F PLASTIC STRIPS Filed Dec. 50, 1950 5 Sheets-Sheet 3 Inventor By George A. Rowley Jan. 13, 1959 G. A. ROWLEY ROLLING 0F PLASTIC STRIPS 5 Sheets-Sheet 4 Filed Dec. 30, 1950 Jan. 13, 1959 G. A. ROWLEY ROLLING OF PLASTIC STRIPS 5 Sheets-Sheet 5 Filed Dec. 30, 1950 Inventor Gearge A. Row/6y United States Patent ROLLING 0F PLASTIC STRIPS George Albert Rowley, Hertfordshire, England, assignor to Plastic Binding Corporation, Chicago, Ill., a corporation of Delaware Application December 30, 1950, Serial No. 203,579

19 Claims. (Cl. 18-19) This invention concerns improvements relating to the rolling of strips of thermoplastic or like material, particularly comb-shaped strips such as are used for sheetbinding purposes. Strips of this kind are described, for example, in the specification of British Patent No. 404,806.

According to the invention, a machine for the purpose set forth comprises heating apparatus for warming the strips, a strip-rolling device, strip-feeding means for advancing warmed strips to the rolling device and mechanism for actuating the said feeding means and rolling device in coordination.

In a preferred machine in accordance with the invention the heating apparatus comprises a main heating means which the strips first pass and by which they are gradually warmed, and a final heating means past which the strips are 'fed immediately before being rolled. The rolling may be effected by wrapping or shaping each plastic strip around a mandrel rod with the assistance of a fabric band and a folder which acts to produce a loop in the fabric around the rod and, after the strip has been introduced between the loop and rod, to maintain the said loop in contact therewith while the strip is rolled on the rod by movement of the fabric band around the same.

With the aforesaid two-stage heating means, the rods are preferably advanced to the rolling device past the final heating means and are themselves warmed thereby. The fabric band is also arranged so that it is carried past the final heating means only and is likewise warmed thereby before assisting in the rolling of a strip, the arrangement being such that the band is not directly affected by the heating action in such a manner or for such a time as to involve danger of scorching.

Such a sequence of warming and rolling actions is well suited to the nature of the plastic materials normally employed. After slow warming, the strip acquires pliability and can be readily wrapped around the mandrel rod to an accurate circular shape. Upon cooling, the rolled strip retains its shape and size, but reacquires its elasticity.

A machine in accordance with the invention can thus be arranged to roll strips from the flat very expeditiously and with uniformity of result. It may further be devised so as to be capable of rolling strips of plastic materials of different thicknesses, widths and lengths.

A preferred form of machine embodying the invention will now be more fully described by way of example and with reference to the accompanying drawings, in which:

Fig. l is a general side elevation of the machine;

Fig. 2 a longitudinal section through the upper part of the machine to a larger scale;

Fig. 3 a detail view, partly in side elevation and partly in longitudinal section, illustrating the folder;

Fig. 4 a section on the line IV-IV in Fig. 1;

Fig. 5 a half plan view of the folder and part of the feeding arrangement; and

Fig. 6 a diagram illustrating the folding action.

The machine illustrated is particularly intended for rolling comb-shaped strips, such as that shown at a in Fig. 5, to a cylindrical form in which they are used in well-known manner for binding sheets. The various parts of the machine are carried upon a rigid upright framework 1 on the top bars 2 of which are arranged a series of devices for operating upon the strips. At a lower level is arranged mechanism for actuating these devices in appropriate timed relation, including a camshaft 3 driven through a worm gear 4( Fig. 1) from a longitudinal shaft 5 which is in turn driven from an electric motor 6 disposed at a yet lower level. Provision may be made for the mechanism to be driven at a range of speeds to suit different thicknesses of material, for example by the selection of an appropriate size of pulley 7 for the V-belt drive 8 from the motor 6. Alternatively, the mechanism might be directly driven by the electric motor and the speed of the motor itself controlled.

An electrically heated main hot plate, indicated generally at 9, with a smooth upper surface flush with the tops of the frame bars 2 is arranged between the said bars. This hot plate, which may be covered with thin scorch-proof linen to prevent sticking of the strips, extends from the front end of the machine to a point adjacent to a transverse roller 10 beyond which is a much shorter hot plate indicated at 11. This plate also has a smooth surface which, however, is set down by an amount equal to the thickness of a linen band or strip 12 which passes over the roller 10 and plate 11 as hereinafter described. Provision may be made for varying the heating effects of the plates 9 and 11 to suit materials of different thicknesses or properties and different rates of advance of the strips through the machine (say between 6 to 12 strips per minute). Thus, the plates may be supplied with current through respective adjustable thermostatic devices 13, 14 (Fig. l) by which the temperatures developed are controlled. The main plate 9 is suitably run at a substantially higher temperature than the final plate 11, for example F. as compared with 65 F. in the case of the rolling of Vinylite strips of 0.015 inch thickness.

For advancing the strips over the hot plates 9, 11 use is made of a step-by-step feeding arrangement carried by a framework 15 which runs by rollers 16 on the bars 2 and is held down on the said bars by rollers 17. The frame members 15 are connected in longitudinally adjustable manner, permitting adaptation of the feed to suit different Widths of strip, to sliders 18 Working in longitudinal guideways 19 fixed to the bars 2. As shown. this connection is effected by means of carrier brackets 20 (Figs. 4 and 5) which are fixed to the frame members 15 and are adjustably secured to the sliders 18 by screws 21 passing through longitudinal slots 21 in the brackets 20. For imparting a reciprocatory motion to the feeding arrangement. the sliders 18 are provided with lugs 22 (Figs. 2 and 4) which project through slots 23 in the bottoms of the guideways 19 and are connected by links 24 to levers 25. The levers 25 are pivoted at 26 on the main framework 1 and are operatively engaged by cam followers 27 with grooves 28 in driving earns 29 on the shaft 3.

A series of transverse strip pushers (as shown, five in number), 30-34, are pivotally mounted at intervals along the frame members 15. Each of the first four pushers 30-33 comprises a plate with a down-turned stripengaging flange 35 (Figures 2, 4 and 5) at its leading edge and with side cheeks 36 by which it is pivotally mounted between the members 15. As the plate may tend to distort due to the heat, it is provided with a strengthening device in the form of a yoke 37 fixed to the ends of the plate which carries a central stud 38 engaged by nuts 39 above and below the yoke 37. The plate can be straightened by adjustment of the nuts 39.

Strips are placed one at a time across the entry end of the main hot plate 9, i. e. in advance of the first pusher 30, either by hand or by an automatic strip-supplying means (not shown). Upon advance (that is movement to the right in Figs. 1 and 2) of the framework 15, the flanges 35 of the several pushers sliding in contact with the plate 9 feed forward the respective strips which are for the time being in advance of them. Upon return of the framework 15, the flanges 35 must then be lifted so as to clear the respective strips to the rear of them before dropping behind the said strips ready for the next step. The pushers are coupled together by upstanding arms 40 and a bar 41, so that it is only necessary to impart the aforesaid lifting movement to one of them. As shown in Figs. 2 and 4, the middle pusher 32 has secured to its blocks 42 with outwardly projecting fingers 43 adapted for co-acting with ramps 44. These ramps, which are of angle section, are pivotally connected at 45 to side cheeks 46 secured to the guideways 19. To permit of adjustment in the longitudinal direction, again to suit different widths of strip, the cheeks 46 are secured by screws 47 passing through elongated slots 48 (Fig. 2) in the said cheeks. A pointer and scale (not seen) may be provided to indicate the correct settings for different strip widths. The ramps 44 normally slope downwardly (Fig. 2) in the direction of advance. During advance of the pushers -34, the fingers 43 pass under the ramps 44, deflecting them upwardly, so that the pusher 32, and with it the other pushers, are unaffected by the presence of the ramps. Towards the end of their movement, the fingers 43 are carried beyond the free ends of the ramps 44 which then drop behind them. Upon return of the pushers. the fingers 43 ride up the ramps 44, causing the pusher 32, together with the other pushers, to be tilted up so that their flanges can pass freely over the strips behind them. When the fingers 43 drop from the ends of the ramps 44 at the conclusion of the return movement, the pushers resume their contact with the plate 9 (Fig. 2) a little behind the respective strips next to be advanced by them. The last pusher 34 which has to pass under a rod magazine and co-act with a rod-pushing arrangement as hereinafter described, is rather lower than the others (Fig. 2) and is required not to be tilted up as much or as early as they are. To effect this, its upstanding arm engages the coupling bar 41 by means of a pin and slot connection at 49. As this pusher 34 has also to pass over the gap beyond the plate 9, it is provided with a rounded strip 34 to prevent its flanged edge from catching on the end of the said plate 9 in its return motion.

The strips are rolled around cylindrical metal mandrel rods 50, for example solid or tubular rods of steel or brass plated and polished and rounded somewhat at the ends. A vertical magazine freely holding the rods one above another is provided substantially above the roller 10 between the hot plates 9 and 11. The magazine consists of two angle-shaped uprights 51, fixed one on the outside of each frame bar 2, and two adjustable plates 52. The rods, which are long enough to project beyond the bars 2, are located endwise between the longitudinal flanges 51 of the uprights 51 (Fig. 5) and their ends are guided between the transverse flanges 51 of the said uprights and the edges 52 of the plates 52 (Fig. 2). Released from the bottom of the magazine one at a time, as hereinafter described, the rods are advanced over the plate 11 on the bars 2 and under guide edges 52 (Figs. 2 and 3) on the plates 52. A single adjustment means is provided for simultaneously setting the edges 52 and 52 to suit rods 50 of different diameters. For this purpose, pairs of studs 53 which are carried like crank pins, but with slight radial freedom, in worm wheels 54 mounted in the said flanges, 51 are passed through. slots 55 (Fig. 2), inclined at an angle of in the said flanges and are secured to the plates 52. For adjusting the worm wheels 54 in unison, they are turned 4 through a common worm shaft 56 by a knob 57. The plates 52 can be secured in the adjusted position, indicated by a pointer and scale 58 (Fig. 1), by means of lock nuts 59 on the studs 53.

Detents 60 pivoted to the plates 52 at 61 and loaded by springs 62 normally prevent the lowest rod 50 from leaving the bottom of the magazine. This rod can, however, be forced past the detents by a sliding pusher 63 which is periodically actuated similarly to, but independently of the strip pushers 3034. Separate sliders 64 (Fig. 2), working in the same guideways 19, are driven through levers 65 by cam grooves 66 in the opposite faces of the cams 29 to the grooves 28. The rod pusher 63 actually comprises two side parts each engaging one end of the rod 50 by a finger 63 and leaving between them a free space through which the strips can be pushed as hereinafter described. Each side part has, behind the finger 63 a ramp 68 and an elevated portion 69 which serves to hold up the next rod 50 (see Fig. 2) in the magazine whilst the fingers 63 are in the advanced position, so that the last strip pusher 34 can advance and return freely below the said rod and between the said side parts.

Beyond the final hot plate 11, are vertically guided sliding latches 70 which are loaded towards their upper, rod-obstructing, position (Fig. 3) by tension springs 72. These latches 70 have ramps 73 on the side towards the magazine, so that they can be caused to yield by a rod advancing under the guide edges 52 and allow it to pass, whereafter they rise again to prevent return of the rod. Commencing at this point, sloping guides 74 for the ends of the rods lead to respective sides of a rod-collecting receptacle 75 whose ends are open at the top, at 76, to permit removal of the first rod 50 therein.

The band 12 already referred to is suitably a selvaged linen band slightly wider than the length of the longest strips to be handled, but not as wide as the length of the rods 50. One end, carrying a weight 77, hangs vertically, between the hot plates 9, 11, from the roller 10. The hanging portion (Fig. 3) passes between a fixed, but adjustable jaw 78 and a movable jaw 79 of a bandclamping device. The jaw 79, which is pivoted at 80 is actuated by a cam 81 through a rod 82 having a compression spring 82 coiled around it, the jaw being closed through the intermediary of the spring.

Assuming that the band-folding device, hereinafter described, is in its inoperative position (Fig. 3), the band 12 passes from the roller 10 over the plate 11 and over a roller 83 forming part of the said device and finally hangs down over a further roller 84 mounted in the frame bars 2. These rollers, all of which are freely rotatable, ensure the minimum of frictional resistance to movement of the band 12. The last named hanging portton of the band carries a bar 85 which is engageable by spaced bars 86 (Fig. 3) carried between twin levers 87 pivoted at 87 (Fig. l) and actuated by grooves 88 in cams 89 on the shaft 3. With the bars 86 in contact with the bar 85, downward movement of the levers 87 will cause the band 12 to be pulled from left to right over the hot plate 11 and associated rollers against the resistance of the weight 77. Upon upward movement of the levers 87, however, the bar 85 and band 12 need not follow (and will not follow as long as the clamping jaw 79 is closed), as there is no positive connection between the said band and the levers 87.

The folder roller 83 is carried between the ends of part-circular arms 90 which are rotatably mounted in the frame bars 2 on a shaft 91 situated beyond the hot plate 11. The bars 2 are cut away at 83 to accommodate the roller 83. Sprocket wheels 92 fast on the shaft 91 are each engaged by a chain 93 which hangs thereovcr. The chains 93 are adjustably connected at one end to twin levers 94 (Fig. l) pivoted at 87 and actuated by cam grooves 95 in the faces of the earns 89 opposite to the grooves 88. At the other end, the chains 93 are connected to rods 96 loaded by weights 97 and by compression springs 98 abutting against fixed rod guides 99, the loading serving to steady the movement imparted to the arms 90 and to assist the return position of the said movement. Latch mechanism (Fig. 3) for holding the arms 90 in the operative or rolling position comprises latch levers 100 which are fixed on a shaft 101 rotatably mounted in fixed brackets 102 and are biased by a spring 103 towards the engaged position (Fig. l) in which they enter notches 104 in the arms 90. The levers 100 are movable towards the releasing position by a. trip rod 105 which is connected to an arm 106 on the shaft 101 and carries a stop 107 engageable by a fork 108 carried by one of the levers 87. p

The manner of operation of the machine is as follows:

The machine is warmed up to the degree of heat re quired and the magazine 51, 52 is filled with rods 50. The motor 6 is switched on to set the mechanism in motion and the placing of strips, with the spines of the combs leading, in front of the first pusher 30 is commenced. In the manner described above, these strips are advanced step-by-step over the main hot plate 9 and are preheated thereby. During these initial steps, rods 50 willpass through the folder in the manner now to be described, but idly as no strips have yet arrived. The rods, which thus become warmed, roll into the receptacle 75 from which they are returned one at a time to the top of the magazine by the operator.

Assume that the machine is now about to commence an operative cycle, that is that a strip will be advanced to the folder by the pusher 34 at the next forward stroke of the feeding arrangement. The initial condition is shown in Fig. 3: The folder arms 90 are in the retracted position. The levers 87 are in their uppermost position and the clamp 78, 79 is in the released position, so that the band 12 is in the extreme position to which it can be drawn by the weight 77. The strip pushers 30-34 and the rod pusher 63 are in their respective retracted positions. As the cycle commences, the rod pusher 63 advances, pushing the lowermost rod 50 past the detents 60, under the guide edge 52 and over part of the band 12 resting on the final hot plate 11. Shortly after the rod has commenced to move, the arms 90 commence to swing anti-clockwise from the position shown in Fig. 3 towards that shown in Fig. 2. As the rod passes the latches 70, the band 12 is wrapped around it by the folder roller 83. When the arms 90 reach their end positions they are automatically engaged and held by their latches 100 (Fig. l). The band at this stage follows an almost figure-of-eight course (Figs. 2 and 6) in which it passes around a substantial proportion of the circumference of the rod 50 as well as the roller 83.

Asthe folder arms approach the operative position, the pusher 34 commences to advance the foremost strip under the next rod 50 in the magazine (held up by the elevation 69) and over the band 12 resting on the hot plate 11, so that it finally enters between the rod 50 and the band 12 (Fig. 6). Just before the said pusher 34, followed by the rod pusher 63, then commences to return, the levers 87 start to descend, causing the part of the band which is looped around the rod 50 to entrain the rod and the strip a, so that the strip is wrapped and rolled around the rod by the band. The width of the strip is such that the comb teeth are caused to overlap the spine portion and are wrapped over the same in the known relationship. The warm pliable strip is rolled by the band 12 tightly around the rod to ensure that it takes the shape of the latter. When the levers 87 reach the end of their downward movement, the arm latches 100 are tripped and the clamp jaw 79 is caused to grip the band 12. The arms 90 swing back with the roller 83 and the loops in the band are unfolded. The clamp 78, 79, which has prevented the band from running back under the action of the weight 77 and thus rotating the rod 50 and rolled strip reversely, is then released and the band is drawn back 6 to'its initial position (Fig. 3) by the weight 77. The rod 50 with the strip rolled around it, runs freely down the guides 74 into the receptacle 75, cooling taking place. In the meanwhile, a fresh cycle is being initiated with another rod and strip. The operator periodically removes the foremost rod from the receptacle 75, slips off the rolled strip, which has by now set in the rolled shape. and places the rod in the magazine.

Normally, strips of required length will be rolled one at a time, one on each rod, but two or more short strips could be rolled on each rod, side by side.

What I claim is:

1. A machine for automatically rolling comb-shaped plastic strips each into a separate roll, comprising heating apparatus for warming the strips, a magazine for mandrel rods, means for curling individual warmed strips at a rolling station into separate rolls about mandrel rods, said means comprising a strip rolling device, strip feeding means for advancing strips to said heating apparatus where they are softened and then to the rolling device, mechanism for actuating said feeding means and rolling means in coordination, heating apparatus to warm the mandrel rods, and means for advancing the mandrel rods selectively in coordination with the action of the strip feeding means and rolling device first to said last-mentioned heating apparatus to warm them and then to said rolling device where the strips are wrapped around warm mandrel rods.

2. A machine for automatically rolling comb-shaped plastic strips each into a separate roll, comprising heating apparatus for warming the strips, a magazine holding a supply of mandrel rods, means for curling individual warmed soft strips into separate rolls about said rods at a rolling station, said means comprising a strip rolling device, strip feeding means for advancing strips to said heating apparatus where they are softened and then to the rolling device, mechanism for actuating said feeding means and rolling means in coordination, the heating apparatus including a main heating means over which the strips first pass and by which they are gradually warmed, a final heating means past which the strips are fed immediately before being rolled, means for advancing the mandrel rods from said magazine to said rolling device selectively in coordination with the action of the strip feeding means and rolling device, said last-mentioned means advancing the rods to the final heating means to the rolling device to heat the rods.

3. A machine for automatically rolling plastic strips into a separate roll, comprising heating apparatus for warming the strips to soften them, means for curling individual soft strips into separate rolls including a strip rolling device, a magazine for mandrel rods. mandrel rod feeding means for advancing the rods to the rolling device in coordination with the action of the strip feeding means and rolling device, said rod feeding means advancing the rods to the heating apparatus and then to the rolling device to heat the rods, strip feeding means for advancing soft strips to the rolling device, and mech anism for actuating both of said feeding means and said rolling device in coordination.

4. A machine for automatically rolling comb-shaped plastic strips each into a separate roll, comprising heating apparatus for warming the strips, means for curling individual warmed strips into separate rolls, said means comprising a strip rolling device, strip feeding means for advancing warmed strips to the rolling device, mechanism for actuating said feeding means and rolling means in coordination, the heating apparatus including a main heating means over which the strips first pass and by which they are gradually warmed, and a final heating means past which the strips are fed immediately before being rolled, the strip feeding means comprises a reciprocatory feeding device including a plurality of step-bystep pushers for advancing the strips over the heating apparatus, and means for lifting the pushers over the strips in the return movement of the pushers.

5. A machine for automatically rolling plastic strips into a separate roll, comprising heating apparatus for warming the strips to soften them, means for curling individual soft strips into separate rolls including a strip rolling device, strip feeding means for advancing soft :trip. LO the rolling device, and mechanism for actuating said feeding means and rolling device in coordination, the strip feeding means comprising a reciprocatory feeder device including a plurality of step-by-stcp pushcrs for advancing the strips over the heating apparatus and means For lifting the pushers over the strips in the return movement of the pushers, including a pivotally mounted ramp and means for causing the ramp to raise the pushers during their return movement and allow them to pass without being raised during the strip feeding movement. and means for adiusting the pusher lifting ramp in the direction of strip movement to adapt the feeding means to strips of ditferent widths.

n. ln a machine for curling fiat plastic blanks into bindings. means providing a blank heating zone and an intermediate blank rolling station, heating means disposed in said blank heating zone, means for advancing a blank throug said heating zone to soften it and toward said rolling station, a mandrel support at said rolling station, a mandrel about which the blank is adapted to be rolled, a flexible strip extending over said support in contact therewith and shiftable linearly thereover in opposite direction means for creating a bight in said strip and [or carrying said bight over the mandrel when the latter is positioned on said strip above the support whereby the strip is partially wrapped around said mandrel, said advancing means serving to introduce the leading edge of the blank issuing from said heating zone between the t portion of the strip and mandrel, and means for shifting said sheet linearly and endwise in the path provided or it by said support and bight to confine the blank between the mandrel and strip and cause the blank to become wrapped on the mandrel.

in a machine for curling fiat plastic blanks into bindings by :1 rolling process, a flexible strip, means for supporting the same horizontally and for heating it, means for positioning a mandrel above the strip, means for creating a bight in said strip and for carrying said bight over a mandrel that may be positioned whereby the strip is partially wrapped around the latter, means for advancing a plastic blank over the heated part of said strip to heat and soften the blank and to introduce the leading edge of the blank between the bight portion of the strip and mandrel, and means for shifting said strip linearly whereby the heated strip carries the heated blank around the bight in confinement between the mandrel and the strip and causes the blank to become wrapped on the mandrel.

8. In an apparatus for forming plastic bindings, a heating plate, a flexible strip extending over said plate and shfftable thereover endwise and linearly, means for advancing a blank along said strip above the plate toward a region of discharge to soften it, means for positioning a mandrel over the strip, means for creating a bight in said strip and for carrying the bight over a mandrel loosely positioned on the strip whereby the strip is par tially wrapped about a mandrel, said advancing means serving to introduce the leading edge of the blank between the strip and partially wrapped mandrel, and mean for shifting said strip endwise and linearly in a direction extending toward said discharge region to confine the blank between the mandrel and strip and cause wrapping of the blank around the mandrel.

9. In an apparatus for forming plastic bindings from flat blanks, a heating plate having a flat upper surface, a flexible strip extending over said surface and movable in opposite directions linearly thereover toward and away from a discharge region, a weight normally biasing said Bil strip for movement in a direction away from the discharge region, means for advancing said blanks in succession over said strip above said heating plate toward said discharge region to soften them, means operable under the control of said blank advancing means for feeding mandrels one at a time onto the surface of said strip above the heating plate, means operable in timed relation to the blank advancing means for moving said mandrels over the surface of said strip toward said t'clischarge region for heating thereof by direct heat transfer, means operable when each blank approaches said discharge region for creating a bight in said strip and for carrying said bight over the mandrel to partially wrap the strip around the latter, said advancing means serving to introduce an edge of the blank between the mandrel and strip, and means for shifting said strip linearly in a direction toward said discharge region against the action of said biasing Weight to cause the blank to become wrapped about the mandrel to produce a binding.

10. In a cyclically operable apparatus for forming plastic bindings from flat blanks, a heating plate, a flexible strip extending over said plate, means for moving said strip linearly over the plate toward a discharge region, means for advancing blanks in succession on said strip above said heating plate to soften them toward said discharge region, a magazine for mandrels, means for successively releasing mandrels from said magazine, and for heating the mandrels by advancing said mandrels over said strip at the heating plate, and means operable when each blank approaches said discharge region for curling the blank between the strip and a preheated mandrel.

l 1, A cyclically operable apparatus for forming plastic bindings from fiat blanks, a heating plate, a flexible strip extending over said plate, means for moving the strip lengthwise along the plate towards a discharge region, means for advancing blanks in succession on said strip toward said discharge region whereby the blanks assimilate heat from said heating plate through the strip to soften them, a magazine for mandrels, means operable in timed relation to the movement of the blanks for successively releasing mandrels from said magazine and depositing the same on the surface of said strip above said heating plate and including means for heating the mandrels by advancing mandrels over said strip, and means for curling an advancing blank between the strip and a preheated mandrel.

12. In an apparatus for forming plastic bindings, a plate, a flexible strip extending over said plate, means for positioning a mandrel loosely on said strip above said plate, a roller for releasably holding a bight portion of said strip partially about said mandrel, a weight carried at one end of the strip and normally biasing the strip for movement endwise in one direction, means for moving said strip endwise in the opposite direction against the action of said biasing weight, means for holding said strip in position against the return action of said weight after the strip has been moved to a limit, and means operated upon release of said bight-holding roller from the strip for releasing said holding means.

13. In a machine for rolling fiat plastic blanks into bindings, means providing a blank heating zone and a blank rolling zone, a heating plate disposed in said blank heating zone, means for advancing the blanks successively through said heating zone over said plate and toward said rolling zone, rolling instrumentalities in said rolling zone, a magazine for mandrels, an impeller for withdrawing the leading mandrel in said magazine and for impelling the same toward said rolling instrumentalities, and a yieldable detent carried by said magazine and positioned in the path of movement of the leading mandrel in said magazine, said detent being adapted to yield to release the leading mandrel in the magazine when the latter is engaged by said impeller and to engage the next adjacent mandrel to prevent release thereof.

14. In a machine for rolling flat plastic blanks into bindings, means providing a blank heating zone and a blank rolling zone, a heating plate disposed in said blank heating zone, means for advancing the blanks successively through said heating zone over said plate to soften them and toward said rolling zone, rolling instrumentalities in said rolling zone, a magazine for mandrels, an impeller for withdrawing the leading mandrel in said magazine and for impelling the same toward said rolling instrumentalities, a yieldable detent carried by said magazine and positioned in the path of movement of the leading mandrel in said magazine, said detent being adapted to yield to release the leading mandrel in the magazine when the latter is engaged by said impeller and to engage the next adjacent mandrel to prevent release thereof, a guide carried by said magazine and overlying said plate for directing the mandrels toward said rolling instrumentalities, and means for adjusting said magazine and guide relative to said plate to accommodate mandrels of difierent diameters.

15. A machine for automatically shaping plastic combshaped strips by curling them around a mandrel, comprising a device for curling a strip around a mandrel rod at a rolling station, strip feeding means for automatically advancing strips in succession to the rolling station, mechanism for actuating said feeding means and said curling device in coordination, and means for heating said mandrel rod and for advancing the warm rod to the rolling station where a strip is wound about the warm mandrel rod.

16. A machine such as defined in claim 15 wherein said last-mentioned means feeds the rod first to said heating means and then to said rolling station, in coordination with the action of the strip feeding means and curling device.

17. A machine for automatically shaping plastic combshaped strips by curling them around a mandrel, comprising heating apparatus for warming the strips, a device for curling each warmed strip around a mandrel rod at a rolling station, strip feeding means for automatically advancing strips in succession to the rolling station, mechanism for actuating said feeding means and said curling device in coordination, means for advancing a rod to the rolling station where a strip is wound about the mandrel rod, and means for heating the rods as they 10 advance toward the curling device and before they reach the curling device.

18. A machine for the automatic rolling of plastic strips, particularly comb-shaped strips, each into a separate roll, comprising: heating apparatus for warming the strips to soften them, a magazine for mandrel rods, a strip-rolling device for curling individual strips around mandrel rods at a rolling station, flat strip support means extending up to said rolling station for providing a support for said strips to prevent deformation thereof until after they are presented to said rolling device, stripfeeding means for advancing warmed, softened strips to the rolling station over said support means, means for advancing mandrel rods from said magazine to the rolling station over said support means in coordination with the action of the strip-feeding means and rolling device, said strip feeding means advancing said strips beneath said mandrel rods at said rolling station, and said support means supporting said strips against deformation until they are wound around said mandrel rods.

19. A machine for automatic rolling of plastic strips, particularly comb-shaped strips, each into a separate roll, comprising: heating apparatus for warming the strips to soften them, a magazine for mandrel rods, :1 strip-rolling device for curling individual strips around mandrel rods at a rolling station, strip-feeding means for advancing warmed, softened strips to the rolling station, mandrel rod feeding means for advancing the rods to the rolling station in coordination with the action of the strip-feeding means and rolling device, said rod-feeding means advancing the rods to the heating apparatus where the rods are heated and then to the rolling station, and mechanism for actuating said strip-feeding means, rodfeeding means and rolling device in coordination.

References Cited in the file of this patent UNITED STATES PATENTS 1,340,824 Crozier May 18, 1920 1,695,327 Goldston Dec. 18, 1928 1,742,845 Brainerd Jan. 7, 1930 1,821,413 Whitehouse Sept. 1, 1931 2,211,743 Nelson et al Aug. 13, 1940 2,304,629 Emmet Dec. 8, 1942 2,381,185 Rogers et al Aug. 7, 1945 2,403,644 Emmer July 9, 1946 2,424,540 Bogoslowsky July 29, 1947 2,442,598 Harrison et al June 1, 1948

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