US2492413A - Stiffening uppers of shoes - Google Patents

Description

Dec. 27, 1949 1.J. BROPHY STIFFENING UPPERS OF SHOES Filed NOV. 22, 1944 2 Sheets-Sheet 1 lnuenor: John Erop/'ll y.

Dec. 27, 1949 .1. J. BROPHY 2,492,413

STIFFENING UPPERS OF SHOES Filed Nov. 22, 1944 2 Sheets-Sheet 2 lwerzor' John J Brophy Patented Dec. 27, 1949 UNITED STATES PATENT OFFICE srIFFENmG verras or snoEs John J. Brophy, Salem, Mass'., assigner to United Shoe Machinery Corporation, Flemington, N. J., a corporation of New Jersey Application November 22, 1944, Serial No. 564,605

Y 1 Claim. 1

This invention relates to stiiening selected portions of the uppers of shoes and is herein set forth in connection with stiffening the toe portions and the rear portions of uppers.

It is common to provide a toe stiifener blank, usually one having a fabric base impregnated with a stiffening substance, which can be softened and rendered limp by treatment with a solvent or with heat; to incorporate the softened blank in an assembled upper; and then to conform the upper with the softened blank to a last, the blank becoming hard and resilient upon evaporation of the solvent or upon dissipation of the heat.

There are certain disadvantages involved in the use of stiffener blanks of the general type outlined above. They can be most conveniently incorporated in the assembled uppers, and are usually so incorporated, just prior to the pullingover operation, a special solvent-applying or heatapplying apparatus being provided for rendering them temporarily limp. They become hard and resilient as soon as the solvent has evaporated or the heat dissipated; but it is difilcult to maintain them limp, and hence in condition for being conformed to the last, for just the right time, and then to have them become hard soon afterward so that the last may be removed from the upper. These and other disadvantages present very considerable difliculties to the use of such blanks as counter stiffeners so that, although toe stiifeners of the general type under discussion are widely used, no shoe manufacturer, so far as I am aware, uses them as counter stiiieners.

The patent to Schwartz, No. 1,215,875 of February 13, 1917, discloses a method intended to avoid the disadvantages involved in the use of stiffener blanks which are given a preliminary treatment to render them soft and limp before they are conformed to the last. This patent discloses a method which comprises the use of a stifener blank carrying shellac in powdered or broken form, whereby the blank is limp When cold and dry. Such a stiilener blank is incorporated in the assembled upper of a shoe and conformed to the last. After the shoe is lasted, the part of the upper which contains the stiffener blank is subjected to radiant heat to fuse the shellac whereby the particles of shellac are caused to run together so that, when the shellac hardens, a stiflened portion of the upper results. Shellac is not a satisfactory material for use in stiffening portions of the uppers of shoes; and subjecting the selected portion of the upper to radiant heat for approximately an hour at a, temperature between 210 and 250 F., as is necessary in the patented process, is extremely injurious to all but a very few kinds of leather. Consequently no one, so far as I am aware, has ever made use of the Schwartz process, said patent never having advanced at all the art oi' shoemaking.

According to the present invention there is incorporated in a selected portion of the upper, in cold, dry, non-fused form, a resinous material which can be caused to coalesce when subjected to the heating' efect of a high-frequency iield. The resinous material, while cold and dry, is conformed with the upper of a shoe to a last and subsequently is subjected to the heating effects of a high-frequency eld. This material produces a tough, strong stlifener. By making use of a high-frequency field the heat is applied directly to the stiffening material. The heat need be applied for only a very short interval; there is no danger of injuring the upper of the shoe such as is present when radiant heat is used, and a resinous material having a comparatively high melting point can be employed.

Preferably the electrodes of the high-frequency apparatus are flexible members mounted in a flexible presser which is pressed'against the selected portion of the upper. In this manner not only is a stray field from the electrodes made use of to heat the stiffening material but the stiiener blank is caused, by the action of the presser, to conform very accurately to the contour of the last beneath it, and the upper, stiffener and lining are firmly bonded together.

The invention comprises a method and an article which is used in the method.

An apparatus for use in carrying out a step of the method is disclosed in divisional application Serial No. 610,110, illed August 10, 1945, now United States Patent No. 2,406,738, of September 3, 1946.

Certain aspects of the method not claimed herein are claimed in my applications Ser. No. 91,606 and Ser. No. 91,607, both filed May 5, 1949.

Referring to the accompanying drawings,

Fig. 1 is a plan of a toe stiii'ener blank according to the present invention;

Fig. 2 is a similar view of a counter stifl'ener blank;

Fig. 3 is a plan of an apparatus for subjecting .the front and rear portions of the upper of a lasted shoe to the heating effect of a high-freqency field, a shoe being shown in place, certain parts of the apparatus having been removed or broken away;

Fig. 4 is a vertical longitudinal section of the apparatus and lasted shoe shownin Fig. 3, the plate 69, which has been removed in Fig. 3, being shown; i

Fig. 5 is a perspective of the rear electrode holder with the electrodes;

Fig. 6 is a vertical cross section through the rear part of the apparatus and the shoe which are shown in Fig. 3; and

Fig. 7 is a vertical cross section through the forward part of the apparatus and shoe.

The stiffener blanks (Figs. 1 and 2) are preferably made by impregnating a sheet or porous base, such as cotton flannel, felt or paper, with a solution of a plastic stiiening material consisting essentially of a synthetic resinous material, such, for example, as ethyl cellulose, in a solvent, such, for example, as acetone; treating the impregnated base with a non-solvent liquid,

such, for example, as water, which is miscible u with the solvent but is not a solvent for the resinous material, so as to precipitate' the resinous material in the base; and then drying the sheet.

'I'he procedure outlined above for impregnating a porous sheet by precipitating in its interstices a resinous material may be carried out in any suitable manner, for example, as disclosed in United States Letters Patents No. 1,256,240, dated February 12, 1918, and No. 1,353,599, dated September 21, 1920, both granted upon applications of Stanley P. Lovell. 'I'he dry sheet carrying the resinous material in precipitated form, if stiffer than desired, may be rendered limp or flexible by any suitable treatment. For example, the sheet may be carried between moving belts which make sharp reverse turns over small rolls so as to `bend the sheet sharply first in one direction and then in another; or the sheet may be run through a mangle and thus rendered limp and flexible by reducing the precipitated resinous material more or less to discrete particles. After the above treatment the stiffener blanks may be cut out of the sheet.

It may be desired to omit the precipitating step, in which case the solvent may be caused to evaporate, and the dry sheet containing the resinous material treated to render said sheet limp. It will be understood that the base, instead of being a separate member, may be some part of the assembled upper of a shoe, for example, the doubler,.which has, for example, been cut out of an impregnated sheet. Also, if desired, the porous base may be omitted, and limp, easily conformable stiflener blanks produced by spraying a suitable solution of a synthetic resinous material in a suitable manner upon a smooth surface, peeling off the comparatively thick, porous sheet which results when the solvent has evaporated, and cutting out blanks from such a sheet. In any case, there will be incorporated in the upper of a shoe a synthetic resinous material which while cold and dry may be conformed with the upper to a last and may be later caused to coalesce by subjecting it to the heating effect of a highfrequency field.

Limp stiffener blanks, for example. a `toe stiffener blank (Fig. 1) and a counter stiilener blank (Fig. 2), may be incorporated in the upper of a shoe at any suitable stage in the manufacture of the shoe. Conveniently the blanks may be incorporated in and become part of the upper during the assembling of the parts of the upper in the stitching room. The upper may then go through the regular shoe-manufacturing operations, including being mounted upon and conformed to a. last; and, a't any time after the lasting has vbeen completed, the toe and heel ends of the upper, with the conformed, limp'stiffener therein, may be subjected to the heating effect of a high-frequency field.

The resinous stiffening material, as has been stated, is preferably incorporated in selected portions of the upper by incorporating two separate stifener blanks such as are shown in Figs. 1 and 2. In Fig. 6 a. lasted upper is indicated at |00, a stiffener at 200, a lining at 300, and a last at 400. After the stiieners have been incorporated in the upper and the upper has been lasted, the next step is to subject the selected portions of the upper to the heating eil'ect of a high-frequency field. A convenient method of accomplishing this will now be described in connection with a suitable apparatus.

Referring first to Figs. 3 and 4, the apparatus comprises a base 9 upon which are mounted a front section and a rear section. The front scction comprises a block I which is hollowed out to receive a flexible rubber bag I I shaped to receive the toe portion of a lasted shoe, said block being adjustable toward and from the rear section in a guideway l5 formed in the base 9 and held in adjusted position by a clamping screw I1, the purpose of this adjustment being to provide for shoes of different lengths. The rear section also has a flexible bag I9 which is shaped to extend around the rear and sides of the shoe, and the wings or sides of which can be moved from open to closed position. Two electrode holders 2|, 23, the details of construction of which will be described later, are placed respectively upon the toe portion and the rear portion of the upper on the lasted shoe, and then the lasted shoe, with the electrode holders in place upon it, is placed as shown in Figs. 3 and 4 with the electrode holder 2| resting against the bag |3 and the electrode holder 23 resting against the bag I9, the block l having been adjusted horizontally and locked in position by the clamping screw l1. A cover 25, which is hinged to the front section at 21, is swung over and down into horizontal position and fastened in this position by a hasp (not shown) on the cover, the slot in the hasp receiving a staple (not shown) driven into the block a pin (not shown) being passed through the staple to hold the hasp in place. The cover 25 (Fig. 7) has set into it near its middle a block of resilient material 29 which presses down the electrode holder on the toe portion of the shoe. A similar cover 3| (Fig. 3), hinged to a stationary part of the rear section at 33, is swung over and its hasp (not shown) held by a staple 35 which is driven into a stationary part of the rear section. This cover 3| (Fig. 6) has set into it near its middle a block of resilient material 3l which presses the electrode holder 23 and the rear portion of the lasted shoe against the flexible bag I9. Next, the sides or wings of the rear bag i9 are forced inwardly in a manner presently to be described so as to press the sides or wings of the rear electrode against the upper and the upper against the sides of the rear portion of the last.

In the manufacture of shoes it is usual to tack an insole to a last, the heel end of the insole being somewhat narrower than the widest part of the rear end of the last so that there is a reentrant angle which extends around the heel end of the last and insole, said angle (Fig. 6) being bounded on one side by the edge of the insole 500 and on the other by the somewhat curved surface at the bottom of the heel end of the last. It is desirable that the finished stiffener should bridge this angle; and in order that the stiifener, while soft, shall not be forced into this angle, the inner wall of the bag at this locality is given sufficient rigidity. In the illustrated construction there is vulcanized or otherwise attached to the adjacent portion of the inner wall of the bag |9 a strip of resilient material 39, wedge-shaped iny cross section, so that no objectionable crease or depression appears in the outer of the finished shoe.

With the shoe and the electrodes thus firmly held, a uid under pressure, for example, compressed air, is forced through two pipes 4| and 43 into the rear bag |9 and through the pipe 45 into the front bag I3 to distend the bags. Thereafter the electrodes are energized from the terminals of an oscillator of a high-frequency machine whereby the resinous stifening material is caused to coalesce and, finally, becomes hard, film-like, and resilient. The purpose of the pressure is twofold. First, it presses the electrodes, which are flexible, firmly into contact with the shoe, thereby rendering them much more effective. Second, it presses the outer, the stiffening material, and the lining of the shoe into iirm contact with each other so that the three members are firmly bonded together in the finished shoe.

The general construction and mode of operation having been given above, a detailed description of the parts of the apparatus will now be given. The block of the front section is hollowed out, as has been explained, to receive the resilient bag I3. In order to aid in holding the bag properly in place, a suitably shaped thin plate 41, the inner edge of which extends over the top of the bag, is fastened by screws to the block; and a comparatively thick, substantially upright, but slightly inclined plate 49 is fastened to the block said plate 49 having cut in it a curved bevel-edged opening to iit'closely around the inner (left-hand as viewed in Fig. 4) end of the bag I3. The pipe 45, through which compressed air is forced into the bag, has its inner end upset over one wall of the bag and is Aheld firmly in place by -a nut 5| which is threaded upon the pipe.

The rear section is different from the front section principally because means are provided for causing the sides or wings of the bag |9 to press the electrode holder against the sides of the rear portion of the shoe. This rear section comprises two stationary, upright side walls 53, 55 and a stationary, upright rear vwall 51, all three walls being rigid with the base 9. The rear wall has rounded ends which are adjacent to but somewhat spaced from the side walls 53, 55. These rounded ends have horizontal slots about midway of their height, one such slot being shown at 459 in Fig. 4; and extending vertically through the rounded ends and the slots are vertical pivot pins, one of which is shown at 8| and the tops of both of which are shown at 6| and 63 in Fig. 3. Extending horizontally into the slots and piv- CIJ oted on the pins are flat tongues 85, 61 formed respectively on the rear ends of arms |55, |61 which receive between them the sides of the bag I9, as sho \n in Fig. 6, in which figure the arms have been swung in about their respective pivots 6|, 63 to cause the sides of the bag to press the electrode holder 23 firmly against the upper of the shoe and the upper firmly against the last. Fastened respectively to the tops of the arms |65, |61 are two thin plates 89, 1|; and fastened to the top of the rear wall 51 is a third thin plate 13, the inner edges of these plates extending over the top of the bag |9. The arms |65, |61 are normally held in open or spread-apart position, as shown in Fig. 3, by two tension springs 15, 11, one end of each spring being fastened to an arm and the other end to the base 9. In order to move the arms to closed position against the force of the springs 15, 11, there are provided two cam members 19, 8| pivoted respectively about the stems of screws 83, which are threaded respectively into the side walls 55, 53. The cam members have comparatively long, straight handles which, as viewed in Figs. 3 and 4, are upright, the springs 15, 11 holding the arms |65', |61 open. When it is desired to swing the arms toward each other to exert pressure, the handles are swung down and outwardly about the pivot screws 83, 85. This causes the cam members, which are integral with the handles, to force the arms inwardly. Upon the upper face of the base 9 is a block 81 of resilient material to receive the cone of the last 400.

The electrodes are flexible. They are substantially alike except for their shapes, and consequently only the rear electrode will be described in detail. The holder 23 for the rear electrodes has the general shape shown in Fig. 5, being provided with curved side walls which resemble in shape those of a molded counter stiffener, and with an inturned, substantially flat range at the top. The inner wall of the holder thus corresponds roughly to the shape of the rear portion of the last. The illustrated holder is made of two layers of flexible material, such as leather, a thin layer 88 and a thicker layer 89, the thicker layer having in it a series of holes 90 to receive spirals of wire which constitute the electrodes of the high-frequency machine. Conveniently, if desired, the layers of the electrode holder may be made -of finely woven elastic glass, and the electrodes fastened in place between the glass layers. These electrodes are arranged in sets of two series of three each. To the three members of one set have been applied the reference numerals 9|, and to the three members of the other set the reference numerals 93. The three electrodes 9| are connected to three conductors |9| which in turn are connected to a single conductor 29|. said last-named conductor leading from one terminal of a high-frequency oscillator. The three electrodes 93 of the other set are connected to three conductors |93 which in turn are connected to a single conductor 293, said last-named conductor leading from the other terminal of the high-frequency oscillator, It will be noted that the three electrodes 9| are alternated with the three electrodes 93, and that direct fields lie between these electrodes. It is not, however, such direct fields which are relied upon to heat the stiffening material in the shoe. There is present a series of stray fields extending outwardly and inwardly from the planes between the electrodes, these stray fields being parts 75 of the electrostatic fields which are external to the space between the electrodes. 'and it is this series of stray iields which is principally relied upon. The forward electrode holder is of substantially the same construction as that of the rear electrode holder which has just been described, but differs from the rear holder in that it is shaped roughly to correspond to the shape of the toe portion of a lasted shoe. The conductors for the two sets of electrodes of the front holder 2| are indicated in Fig. 3 at 95 and 31.

The following are examples of solutions. Whic may be used to impregnate a porous base.

Example I Parts by weight Ethocel 100 C. P. Standard 16.25 Rosin (cherry wood) 5.25 Acetamide 6.75 Acetone 75 Methanol Example II Parts by weight Ethocel #250 C. P. Standard 15 Petrex acid 6 Acetone 100 Methanol 28 In this formula "Petrix acid is used in place of acetamide and rosin. This acid is a high molecular weight, synthetic, polybasic acid of terpene origin put out by the Hercules Powder Co. of Wilmington, Delaware.

Example III Parts by weight Ethocel #150 C. P. Standard 16 Polypale ester No. 2 12 Acetone 140 Methanol 28 In this formula "Polypale ester No. 2" is used in place of acetamide and rosin. 'I'his ester is the diethylene glycol ester of polymerized rosin and is also put out by the Hercules Powder Co.

Example IV Parts by weight Ethocel l250 C. P. Standard 10 Rosin (cherry wood) 10 Acetone 120 Methanol 24 Rosin, besides adding to the tackiness of the compound also is more susceptible to the heating effect of a high-frequency field than is the Ethocel. It will be noted that no acetamide, Petrix acid or polypale ester is present in the formula, the large proportion of rosin in this case acting to increase sufficiently the susceptibility of the Ethocel to the heating eil'ect of the highfrequency field. The above formula produces a stifiener which, when hot,` is somewhat more sticky than that produced by Example I and one which will soften at a somewhat lower temperature, but not below that to which the stiiened portion of a finished shoe is liable to be exposed.

Polyvinyl acetate R. H. #410 is a polymerized vinyl acetate put out by the E. I. duPont de Nemours a Co., Inc., of Wilmington, Delaware.

Example VI Parts by weight Normal propyl methacrylate 35 Acetamide 12 Acetone 80 Example VII Parts by weight Normal butyl methacrylate 35 Acetamide 12 Acetone Example VIII Parts by weight Ethocel 100 C. P. Standard 16 Rosin (cherry wood) 12 Hycar 6 Acetone Methanol 20 Example IX Parts by weight Ethocel 50 C. P. Standard 24 Rosin (cherry wood) 12 Hycar 6 Acetone 90 Methanol 20 Hycar, a synthetic rubber, is a butadiene-acrylonitrile copolymer containing in the neighborhood of 25% by weight of acrylonitrile and 75% by weight ot butadiene put out by the Hycar Chemical Company of Akron, Ohio. Like acetamide it has a lower softening point than has the ethyl cellulose. The synthetic rubber renders the stifiener blank more pliable when cold so that the lasting4 operation is facilitated, and enhances the resilient quality of the finished Paraplex X put out by the Resinous Products 8: Chemical Co. of Philadelphia, Pa., is an alkyd type thermosetting resin having a softening range of from 100 F. to 105 F. Durez resin #12687 is a. thermosetting phenol-formaldehyde resin, put out by Durez Plastics l: Chemicals, Inc., of North Tonawanda, New York, which has a softening range of 40-60 C. and a melting range of 70-75 C. Benzoyl peroxide is an accelerator for the curing of the thermosetting resinous material. Altax, benzothiazyl disulfide, put out by the R. T. Vanderbilt Co., of New York, N. Y., is a. rubber accelerator but here probably acts to retard somewhat the curing operation. Titanox R. A. 10MO is a. titanium oxide put out by the Titanium Pigment Corporation of lNew York, N. Y. It serves here principally as a filler.

Having described my invention, what I claim as new and desire to secure by Letters Patent of the United States is:

10 In a method of producing a. stiiening portion REFERENCES CITED in a' Shoe' the steps comprising incorporating m The following references are of record in the a. selected portion of the upper ethyl cellulose in me of this patent: unheated, dry, limp form, associating said upper with a sole member and conforming the upper to I UNITED STATES PATENTS a last, thereafter, while holding the upper so con- Number Name Date Ormed, subjecting the Selected portion to the 1.0701406 Buttereld um 19, 1913 heating effect of a high-frequency Vlefztri field 1,197,437 Brock sept, 5, 1916 C fuse the ethyl CellulOSe and bond it t0 the 1,889.196 Fausse et a1 Nov 29, 1932 upper. l. 2,216,581 Almy oct.1,194o JOHN J- BROPHY- 2,233,477 Hilberg Mar. 4. 1941 2,242,729 Ritchie May 20, 1941 2,252,554 Carothers Aug. 12, 1941 2,343,390 Ushakoff Mar. 7, 1944 2,373,264 Russell Apr. 10, 1945 2,379,059 Ashley June 26, 1945

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