US2014453A - Folding sheet material - Google Patents

Description

Sept.r 17, 1935. T. c. RowN Y FOLDING SHEET MATERIAL` Filed April 27, 1932 .Z/SheetS-Sheet 1 y WVM/TUR'.

@by-W n 17; 1935. `r. QROWEN 2,014,453

FOLDING SHEET MATERIAL Filed April 27, 1932 Y 2 Sheets-Sheet 2 7 Fl g; 2Q

ioo f Thermal UnTs Patented Sept. 1 7, 1935 FOLDING SHEET. MATERIAL Ihomas C. owen, Swampscott, Mass., assigner to United Shoe Machinery Corporation, Paterson, N. J., a corporation of New Jersey Application Appu 2r, 1932, semi No. 601,767

13 claims. (01. iz-ss) This invention relates to a method of folding the margin of a piece of sheet material .by the use of a cement which isnormally not tacky but may be` rendered tacky by the application of a 5 suitable agent and to a folding machine equipped -to handle work which has a coat of this sort of cement.

Inthe manufacture of the uppers of boots and shoes it is customary to fold certain margins of the shoe parts in order to produce smoothly finished edges thereon. Two procedures are in common-use. In the rst the margin of the shoe part vis-skive'd, a coating of cement is applied to the margin, and then the margin is foldedover upon .the body portion'. In the second a narrow binding strip-usually of fabric-is sewed along an `edge of the shoe part, said strip -being provided,`

either before or after itsV attachment, with a coat of cement, and then the free portion of the 20. binding is folded over upon the sheet material. Thus in both cases the cement'acoated margin ofva piece of workis folded over upon the body portionv thereof. vIt has been proposed to use a cement which' is normally non-sticky but is 25, adapted to become sticky upon being treated with a suitable softening agent, for example heat; and the present invention relates to the folding of sheet material with the use of a cement of this kind which is normally non-sticky. .i0 YIt is desirable to strengthen the work at or adjacent to its vfolded edge by the application of a strengthening member such as a piece of tape; and in one aspect the invention comprises a method in which there is directed upon the body' portion of a piece of work having a coating of thermoplastic cement upon a margin thereof, a piece of tape having a similar coating, progressively softening the two coatings and progressively pressing the tape. upon the workand fold- 40 .ing the margin of the work. As herein illustrated, the tape is pressed upon the body /portion of the work close to the cemented margin thereof, the softening is accomplished by a blast of hot gas, and the margin is folded over upon the tape.

Hitheito mechanisms embodied in folding machines -for producing hot gas and directing it uponthe work have comprised an electric heat unit provided with a rheostat for varying its temperature, a blower or fan, and a conduit leading from `the blowe past the heat unit to a nozzle. Such a blowe produces a constantcurrent of air at almost negligible pressure; and consequently a heat unit of considerable capacity must beused. There is thus a comparatively slow of the slowly moving current of air at the noz- 10A zle is diflicult. Moreoverpbecause of` the factthat the nozzle must be pointed down upon the work and the movement of the current of air is comparatively slow, the ,hot air isl more or less dissipated instead of being all carried to the 15 work. In order to obviate these disadvantages there is4 provided, in combination with work.- feedingand folding instrumentalities, anozzle, a

- constant source of heat, a positively acting pump for forcing gas under substantial pressure past 2o the source of heat through the nozzle, and means `for Varying the pressure. In the illustrated machine the source of heat is an electric heat unit through a. spiral passage around which the air is forced, and the positively acting pump is one '25 capable of producing a pressure o f several pounds per square inch; With this construction in which a considerable pressure isrused, the amount of 'heat delivered to the work may be very delicately controlled by manipulating the reliei:` Valve to 8@ increase or decrease the pressure of the air, and practically all of the fast moving air deliver from the lnozzle reaches the work.

Referring now to the accompanying drawings, Fig'. 1 is an elevation of a machine by the use ci 85 which the method may be conveniently practiced.

a piece of work being. shown in process of being operated upon;

Fig. 2 is a detail principally i'n section oi the heating means;

f o Fig. 3 is a `chart showing the amounts of heat delivered at certain speciiied pressures; and

Fig. 4 is a section on an enlarged scale showing a finished piece of work comprising a piece of leather having a piece of tape along one edge w -thereof and a strip of binding folded about the edge of the leather and over upon the tape.

Referring first to Fig. 1 the folding machine comprises a base 5 adapted to rest upon a bench and an arm IV having at its outer end a work sup- 5o yport 9 over -which thework is fed.. The particular work shown is part of the strap of `a ladies" pump and comprises a piece of leather |00 having attached to its margin a strip of fabric binding 200. On the left hand ,side of the-work a piece of 55 tape 300 has been applied to the leather or body sageway S1 in a cylindrical casing 39 mounted on portion of the work, and the binding has been folded over and pressed down upon the tape. On the right-hand side ofthe work, the tape 300 is being directed upon the leather, and the binding 2" is in process of being folded.

As herein illustrated the tape 300 has a coating of thermoplastic cement on that face which, in the finished work, contacts with the leather; andthe binding 200 has a similar coat on that face which, in the nishedwork, contacts with the tape. A presser or creaser l I engages the edge of the leather and has a slot inclined downwardly in the direction of feed movement of the work through which the tape passes as it is directed upon the margin of the leather. A slender guide il engages the edge of the leather, a folding finger, not shown, bends the binding about the edge of the leather, and a hammer I1, having a fourmotion feed movement, presses the binding against the tape and the tape against the` leather and also acts to feed the work intermittently away from the observer as viewed in Fig. 1. The tape 309 is fed in a suitable manner from a reel, not shown, through a guide slot in a small bar I9,

and from there is directed upon the work and fed with the work by the hammer which, stated above, has a four-motionmovement. The small bar i9 has a hole in its inner end to receive a threaded` stud 20 carried by the frame of the machine and is held adjustably in position `by a clamp nut 22.

'I'he folding machine, except for the tape guide, theedge guide Il and certain changes in the shape of some of the work engaging parts is or may be substantially the same as that shown in United states Letters Patent No. 1,702,598.

granted February 19, 1929 upon an application illed in the name of Perley R. Glass and no further description of it will be given since the details of its construction form no partof the present invention and any suitable folding machine may be used. It will be understood, however, that the work, including the tape, is fed intermittently away from the observer, as viewed in Fig. 1, that the tape is progressivelyA directed upon the leather or body portion of the work, and that' l the binding or margin of the work is progressively folded over and pressed upon the tape.

The tape and the binding each carry a coat of thermoplastic cement, the tape being coated on that face which will contact with the work, and the `binding being coated on that side which will contact with the upper uncoated face of the tape as it lies upon the work. In order to soften these .coatings progressively there is provided a nozzle 2| so located as to direct a blast of hot air upon the coated side of the .tape and the coated side of the binding simultaneously. This blast strikes the tape :lust before it enters the guiding groove in the presser foot H and strikes the binding just before it passes this foot. This nozzle is fast to the lower end of a curved pipe 23, the upper end of which (Fig. 2) is fast to a nipple 2i which leads from a straight passageway 21 ln a em\ ber 2l provided' with a hand wheel 2l an rotatably mounted in a sleeve 3l, there being a conical, gas-tight, ground joint between these 'two members which are held from longitudinal movement with respect to' each other by a compression spring 33 seated on' the end of the sleeve ll and engaging a nut Il threaded on the small end of the member 2l. By manipulating this hand wheel, the nozzle may beswung-up into inoperative position at any time. The passageway 'I1 communicates with one end of a spiral pas- .belt, not shown, which may be placed upon any the frame of the machine and having an electric 31 with the outlet of a positively acting air pump 5 45. I'his pump may be ofany suitable type which is capable of producing a considerable pressure of air, the illustrated pump being a rotaryv one driven from any suitable source of power by a 10 one of the three pulleys 49 on the driving shaft 5l. In order to permit the pressure to be varied while the pump is running, a pipe 53 connected at its lower end to the outlet pipe 43, has its upper end closed by a relief valve 55 held down by a compression spring 51 the tension of which may be varied by turning an adjusting nut 59.

The possibilities of an apparatus of this type appear in the chart shown in Fig. 3, which shows graphically the results obtained by the use of a 20 heat unit of watts and pressures from about two ounces to four pounds. The curve of the graph would, of course,- vary somewhat in accordance with the construction of the apparatus and the nature of the materials used but the 25 graph shows in general what occurs. The vertical column of iigures represents thermal units, that is the temperature of th air just outside the nozzle, 'multiplied by the volume of air passing ,through the nozzle per second. The horizontal line "of figures represents the pressure of air at the nozzle in pounds per square inch.' It will be noted that the thermal units delivered by the nozzley increase vry rapidly with increase inl pressure up to one-half pound pressure and continue to increase although less rapidly up to four pounds pressure. With the particular apparatus from which this chart was made and with a piece of work coated with a commonly used commercial thermoplastic cement, a pressure of one 4o pound was found to result in a proper softening ofl the cement.

The 4hot air delivered to the work has a tendency to heat undesirably adjacent portions of the machine; and in'order, to withdraw some of 45 this hot air from the locality adjacent to the work, a suction pipe 6I which leads to the inlet of th'e pump has its intake vopening Il located to withdraw hot air which may collect in the neighborhood of the work-engaging parts of the 5o machine. 'This withdrawal of hot air not only prevents undesirable heating of the work-engaging parts of the machine, vbut carries back tothe pump air which is already somewhat warm and will require less expenditure of heat to raise it 55 again to the desired temperature.

Although the tape has been shown and described as being directed into-such a position on the work that the margin of the work is" folded over upon it, it should-be understood that a0 the invention is not limited to this particular location of the tape, and although the illustrated claim as new andl desire to secure by Letters 7o I Patent of the United States is:

1. The method of folding a piece of sheet material having upon a margin thereof a coat-of thermoplastic 'cement and at the same time said material which comprises I5v progressively directing upon the body portion of the sheet material a separate piece'of tape having on that side which will be in contactv with the sheet material a coat of thermoplastic cement, progressively heating the two coats of cement simultaneously while the tape and the margin are in separated relation, and thereafter progressively pressing the tape against the sheet material and folding the margin.

2. The method of folding a piece of sheet material having upon a margin thereof a coat of j terial having upon a margin thereof acoat .of

thermoplastic cement which comprises progressively directing upon the body portion of the sheet material a separate piece of tape having on that side which will be in contact with the' sheet material a coat of thermoplastic cement, v

thereafter progressively folding the margin over .upon the tape, and progressively heating the two coats of cement prior to the folding operation.

4. The method of folding a piece of sheet material having upon a margin thereof a coat of thermoplastic .cement which comprises progressively directing upon the body portion of the sheet material a separate piece of tape having on that side which will be in contact with the sheet material a coat of thermoplastic. cement, thereafter progressively folding the margin over upon the tape, and directing a blast of hot gas upon the two, coats of cement to soften them prior to the folding operation.

5. The method of folding a piece of work which comprises a piece of sheet material to which a strip of binding coated with thermoplastic cement is attached which comprises progressively directing upon the margin of the sheet material a piece of tape coated with thermoplastic cement on the side which is to contact with the piece of sheet material, progressively heating the cement on the binding and on the tape, and progressively folding the binding over upon the tape. 6. The method of folding a piece of work which comprises a .piece of sheet material 4to which a lstrip of binding coated with thermoplastic cement is attached which comprises progressively directing upon the margin of the sheet material a piece of tape coated with thermoplasticcement on the side which is to contact rwith the piece of sheet material, progressively directing a blast of, hot gas upon the cement on the binding and on the tape, and progressively folding the binding over upon the tape.

7. A machine of the class described having, in combination, a support over which a piece of work is fed, means for folding the margin thereof, means for directing upon the work prior to the folding operation a piece of tape having a coating of hard thermoplastic cement thereon, andmeans for directing upon the tape before it reaches the work a blast of not air to' soften the cement.

8. A machine of the class described having, in combination, a support over which a piece of work having a coating of thermoplastic cement 5 on the margin thereof is fed, means for folding the marginal portion of the work over upon the body portion and for pressing the folded-over margin against the body portion, means for directing a blast of hot gas upon the work prior to the completion of the fold to cause the cement to be softened, and means for withdrawing heated gas from the locality in which it is delivered by the nozzle to avoid undesirable heating of the work engaging parts of the machine.

9. A machine of the class described having, in combination, a support foi` a piece of sheet material having upon a margin thereof a coat of thermoplastic cement, means for feeding the sheet material over the support, means for directing 20,

upon the body portion of the sheet material a piece of tape having a coating of thermoplastic cement on one side thereof, means for softening the coats `vof cement on the tape and on the-margin of the material, and means for pressing the tape against the body of the sheet material and for folding the margin of said material.

10. A machine of the class described having, in combination, a support for a piece of sheet material having upon a margin thereof a coat of thermoplastic cement, means for feeding the sheet material over the support, means for directing upon the body portion of the sheet material a piece of' tape having a coating of thermoplastlc cement on one side thereof, means$5 lfor softening the coats of cement on the tape and on the margin of the material, and means for y folding themargin over upon the tape.

11.-A machine'of the class described having, in combination, a support for a piece of sheet40 Vmaterial having upon a margin thereof a coat of thermoplastic cement, means for feeding the material over the suppnrtmeans for directing upon the she'et material a piece of tape having a coating of thermoplastic cement on one side thereof, 45

. means for directing upon the two coats a blast of hot gas to sOften'them, and means for pressing the tape against the body portion of the sheet material and for f olding the margin.

12. A machine of the class describedhaving, in combination, a support for a piece of sheet material having upon a margin thereof a coat of thermoplastic cement, means for feeding the material over the support, means for 'directing-upon the sheet material a piece of tape-having a coating of thermoplastic cement on one side'thereof, means for directing upon the two coats a blast of hot'gas to soften them, and means for folding the margin over upon the tape. y

13. A macmnevof the dass described having,

in combination, a support over which a pieceof work is fed, means for folding the margin of the work, means for directing upon the work along a f lpath substantially parallel with the edge of the Awork to underlie the folded margin thereof and prior to the folding operation a piece' of tape having a coating of hard thermoplastic cement thereon, and means for heating and softening the', cement prior to the completion of the folding operation. f 70 THOMAS C.' ROWEN.

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