US2200401A - Shoemaking - Google Patents

Description

y 1940- K. STllTTER 2,200,401

SHOEMAKING Filed Dec. 15, 1937 l veflfor' ff/mz A". STE/TTER 3' J 7 mm 07776533 Patented May 14, 1940 UNITED STATES PATENT oFFicI:

, 2,200,401 SHOEMAKING Karl A. Stritter, Nahant, Mass, assignor to United Shoe Machinery Corporation, Borough of Flemington, N. J., a corporation of" New Jersey Application December 15, 1937, Serial No. 179,930

6 Claims.

sired results, all as hereinafter described. The

invention includes also within its scope the novel shoe produced by carrying out this new process.

The present application is a continuation in part of my earlier application Ser. No, 116,848, filed December 21, 1936. A preferred method of treatment consists in applying the plastic material to the bottom of the shoe to which the curved shape of the last bottom has already been imparted and then so molding such material in place on the shoe bottom as to press the same into firm adhesive contact therewith and shapethe material to the desired contour. The material 'is preferably applied in the form' of a strip, either preformed or extruded, and it may be secured adhesively to the shoe bottom by its ownadhesive property or by the application of an adhesive to one or both of the co-acting surfaces. The molding pressure is adequate to bring the material into intimate contact with the shoe bottom and mold it thereon. The results thus produced serve several useful purposes, such as providing a reinforcing filler for the shoe bottom or a rigid stiffener for the curved shank of the shoe, the material in either case being molded to the desired contour and providing a continuous surface for union with the outsole.

An important field of .use for the invention is in the manufacture of womens shoes where the shank has a pronounced curvature and where it must be given an effective stifiening'medium in order to preserve the fine lines of the shoe in wear. Heretofore it has been commercial practice to employ shank stiifeners of metal or wood shaped in predetermined curvature and stocked by the shoe manufacturer in assorted lengths. There are numerous objections to the use of such shank stiffeners both from the standpoint of the shoe manufacturer and from the standpoint of the wearer. In the first place, it is diflicult to locate and effectively anchor a metallic shank stiffener in the shoe bottom because its metal surface does not bond well with adhesives. On

this account metal stiffeners often break loose and float in the shoe bottom and after a short interval of wear out their way through the sole. In the second place, there is always danger of the operator selecting a shank stiffener of the wrong size for the shoe in process and in any case the -predetermined curvature of a commercial stiffener is likely not to correspond exactly to the curva-- ture of the last bottom. Further there is an inevitable waste caused by the necessity of keeping in stock a large assortment of various sizes of such shank stifieners.

On the other hand the novel process of my invention contemplates the use of plastic material which may be supplied in quantity, cut to length, and tempered or softened by heat or solvent so that it may be presented to the shoe bottom in pliable condition, conformed accurately and shaped to the individual shoe. I have referred to stiffening material which is stiff preliminary to its presentation, but alternatively I may use material which is initially plastic and which may be caused to harden by heat or solvent treatment.

In using filler in strip form the operator may adhesively attach one end of the strip to the shoe bottom at approximately the ball line and then draw out the strip to the desired length, simultaneously laying it into and upon the shoe bottom in the curvature of the shank and molding it to the shape most favorable for the shoe bottom and for thereception of the outsole. In addition to the advantages already pointed out, a shoe bottom prepared in this manner presents a continuous face to which the outsole may be adheslvely secured, thus eliminating the unattached area formerly resulting from the employment of a metallic stiffener.

The process of my invention has little or nothing in common with the well-known practice of filling the bottoms of welt shoes with plastic sole filler. Sole fillers for that purpose have no appreciable rigidity and have no effect in maintaining or preserving the curvature of the shank of the shoe. On the contrary, my invention contemplates the employment of a material which may be rendered plastic during the applying operation but which when once molded to final shape has the property of hardening or stiffening into a supporting member of sufficient rigidity to maintain the curvature of the shank permanently and supply the function for which a wooden or metallic shank stiffener has been heretofore considered necessary. I do not mean that the molded shank stiffening material I employ is not somewhat flexible but its flexibility is comparable with the resiliency of a wooden or metallic shank stiffener.

These and other features and advantages of the invention will be best understood and appreciated from the following description of a preferred manner in which it may be carried out as shown in the accompanying drawing in which,

Fig. 1 is a view in elevation of one suitable form of apparatus for carrying out the process,

Fig. 2 is a view in perspectivecorresponding to a portion of Fig. 1,

- Fig. 3 is a view in perspective on a larger scale of the shoe shown in Fig. 2 and the parts immediately engaging it,

Fig. 4 is a view in perspective'of a portion of an alternative form of apparatus, and

Fig. 5 is a fragmentary view of the lasted shoe showing a portion of the outsole.

While the method of my invention may be carried out by first molding plastic material in the shank portion to the desired contour and then treating it with an agent causing it to become stiff and set in molded shape, I preferably proceed by employing a composition of material which is normally stiff or dry and which may become softened to plastic condition by the 'application of heat or a suitable solvent. Furthermore, while such material may be applied to theshoe in any convenient form, as for example by extruding the same onto the shoe bottom, I prefer to use it in strip form and to soften it prior to its application to the shoe bottom. In Figs. 1-3 of the accompanying drawing I have illustrated the material as a continuous strip and I shall now proceed specifically to describe one manner of using it.

The apparatus shown in Fig. 1 is designed particularly for handling the shank stiffener material in the form of a continuous strip it! of treated fibre having the properties above discussed. The apparatus comprises a tank III for solvent supported at a convenient height upon a column II which also has a support for a reel of the strip material l2. The strip material is conducted from the reel downwardly and is immersed in the solvent in the tank. After passing through the solvent and being thoroughly wetted and softened thereby, it is advanced from the tank II] by cooperating feed rollers, carried through a chute l4 and delivered to the shoe bottom at a station sufliciently removed from the tank Hi to afford space for conveniently manipulating the shoe.

The side walls of the tank Ill. are extended upwardly to provide bearings for a shaft I5 on which is mounted a pulley IS. A belt l8 connects this pulley with a pulley l9 driven continuously by any suitable source of power. A long arm 20 is mounted for pivotal movement on a shaft 22 carried by the column II and cooperating strip feeding rolls 23 are carried respectively on a shaft l5 and on a shaft 24 mounted in the arm. The arm normally rests by gravity and a spring 29 on the stop 26 projecting from the front wall of the tank. The strip l2 passes over the lower feed roll and when the arm is in its lower position the rolls are separated and no feeding of the strip takes place.

Carried on the free end of the arm 20 is a shaft 28, and a serrated feed wheel 29 and a,

pulley 30 are fixed to this shaft at opposite sides of the arm. A belt 32 connects the pulley 30 to a pulley 33 on the shaft 24. A second column 34 is located adjacent to the free end of the arm 2ll.

A shaft 35 mounted on this column carries a pressing or molding roll 36 having a transversely concave peripheral surface shaped to impart to the stiffener strip the desired transverse convex contour. The shaft 35 is driven at a suitable speed by a belt 38.

The strip carrying chute I4 is supported at one end on the tank Ill and is also supported by a bracket 39 on the column 34, the position of the chute being such that one end is in alignment with the feed rolls 23 and the other end is in alignment and adjacent to the roller 36. At the delivery end of the chute I4 is arranged a knife arm 40 pivoted to swing about a fulcrum shaft 42 carried on the column 34, the knife arm having at its free end a blade 43 arranged in shearing relation with the end of the chute. The knife arm is normally held in raised position by means of a spring 44 but may be drawn downwardly to effect its shearing function by means of a treadle operated link 46.

When a lasted shoe is presented to the apparatus as shown in Figs. 1-3 the feed wheel 29 is engaged by the overlasted margin of the upper at one side of the shoe bottom and as the shoe is pressed upwardly the arm 20 is raised from the stop 26, the strip [2 is engaged by and between the feed rolls 23 and is fed forwardly through the chute l4. It will therefore be seen that raising of the arm 20 causes simultaneous feeding of the strip and advancing of the shoe toward the right whereby the strip is run onto the shoe bottom as the shoe is advanced. When a sufficient length of material has been delivered to the shoe bottom the operator has merely to lower the shoe allowing the arm 20 to swing downwardly and thereby interrupt the strip feeding action. The knife may thereupon be given a cutting stroke from the treadle or other actuating mechanism connected to the link 46 and the strip cleanly severed at the end of the chute.

In Figs. 1 and 2 a shoe upper 41 lasted upon a last 48 is shown as in condition for receiving the shank stiffening material l2. The overlasted margin of the upper is secured to the insole and forms a relatively flat surface which may be engaged by the serrated feed wheel 29. The insole has been conformed to the concave curvature of the last bottom and has thus acquired the longitudinal curvature which it is desired to preserve in the finished shoe. It is desired to present and lay the shank stiffening material in the shoe bottom between the edges of the iverlasted upper from approximately the ball line of the shoe to the rear'end of the heel seat. By temporarily lifting the arm 20 the operator may cause the end of the plastic strip I 2 to advance from the end of the chute l4 so that it may be located on the shoe bottom as shown in Figs. 1 and 2 at approximately the ball line of the shoe. The shoe is then presented with the end of the strip material substantially under the roll 36 and the shoe is pressed upwardly by the operator, thus setting the shafts 24 and 28 in rotation as already explained. The action of the feed wheel 29 thereupon causes the shoe to advance toward the right, the strip l2 being drawn along with it, layed in the curvature of the shank and molded by the action of the roll 36. This continues until the heel seat portion of the shoe is reached whereupon the operator lowers the shoe, bringing the shafts- 24 and 2'3 to rest, and the strip is then severed at the end of the chute l4. Further movement of the shoe toward the right is con-- tinued until the end of the strip I2 has been molded to its rear end thus smoothly filling the heel seat within the overlasted margin of the upper. Thereafter it remains in the shoe bottom adhesively secured to the insole and molded so that it presents a transversely convex surface of the shape desired in the shank.

It will be apparent that the layed and molded strip acts as a filler forthe shank and heel seat portions of the shoe bottom between the marginal edges of the upper. The pressure of the roll 36 serves to make intimate'contact of the strip with the shoe bottom and thus secure the strip adhesively in place. The molding action of the roll also gives the desired contour to the outer face of the strip, this contour preferably being transversely convex and substantially coincident with the top surface of the upper margins thereby providing a substantially continuous surface to be cemented to the outsole.

Following the completion of the strip laying and molding operation the strip is caused to become rigid in place on the shoe bottom. This action will ordinarily be brought about by evaporating the solvent or permitting the same to evaporate at atmospheric or a suitable temperature. Following such step the strip not only serves as a filler and provides an outsole receiving surface'but also forms a shank stiifener for the shoe having approximately the rigidity of a wooden stififener. It is furthermore pointed out that, in contrast to shank stiffeners of metal and, other materials heretofore used, my improved stiffener is anchored securely in place on and throughout its entire contact with the shoe bottom.

One suitable material for use in the manner above described comprises a base of cotton or wool fibre, or a mixture thereof, treated with a cellulose compound and having in its initial condition the appearance and texture of a heavy, close grain felt. When this is wetted with acetone or other suitable solvent it becomes limp, plastic, adhesive and easily moldable. Subsequently, when the solvent evaporates the molded mass acquires substantially the rigidity and resilience of a wooden shank stiffener.

In Fig. 4 I have illustrated in fragmentary view an apparatus for softening the strip by heat rather than by a solvent. In this case the strip is fed to the shoe by cooperating feed rolls 52 and in moving to the shoe the strip passes between plates 54 heated in any convenient manner as by steam from pipes 56. The feeding movement and the extent of the heating plates are such that the strip arrives at and is applied to the shoe in plastic condition. The application and molding of the strip to the shoe may be carried out in any convenient manner, as in the manner illustrated in Figs. 1-3. The strip may be of any suitable thermoplastic material capable of being either hardened by heat treatment, or of being rendered temporarily plastic by heat treatment and then hardening of itself at room temperature to supply the bulk needed to shape the, shank.

One suitable material for use in this manner comprises a base of felt saturated with a resin or with natural gums or a combination thereof and having the property, after being heated and then cooled, of acquiring in .molded shape the rigidity and resilience of .a wooden shank stiffener.

While I have referred particularly to the advantages of my invention in giving body and shape to the shank and in stiifening it, like advantages apply also to the heel seat portion of the shoe in which the material becomes rigid to supply a solid even base molded to fit the cup of the heels or the outsole and to receive heel nails. The elimination of a metal shank stiffener from the breast line of the heel seat is very desirable since it permits the employment of a central attaching nail for the heel or any desired pattern of nailing.

InFig. 5 the filling and shank stiffening material is shown as smoothly molded throughout the shank and heel seat portions of the shoe bottom. In this view also is shown part of the outsole 69 which is cemented to the surface thus provided and may be subsequently secured by other means if desired.

Having thus disclosed my invention and described preferred methods of putting it into practice, I claim and desire to secure by Letters Patent 1. The process of shoemaking which includes the steps of applying plastic material having latent rigidity equivalent to that of a wooden shank'stiffener of substantially the same size to the shank and heel portions of the shoe bottom which has been previously longitudinally curved on a last bottom, applying rolling pressure progressively'lengthwise of the shoe to said material thereby uniting it to the outer surface of the insole, and molding it to fill the space between the overlasted margins of the upper in the shank and heel-seat portions of the shoe bottom, and thereafter permitting the material to become so rigid that it takes the place of a wooden shank stiffener in the shoe bottom; I

2. The process of shoemaking which includes the steps of applying an adherent plastic material having latent rigidity equivalent to that of a Wooden shank stiffener of substantially the same size to the shank portion of the bottom of a shoe which has been previously curved to the bottom of a last so that the material adheres to the insole, molding the material between the overlasted margins of the upper to present a transversely curved face, thereafter permitting the of a wooden shank stiifener, and then attaching an outsole in continuous engagement with said rigid material.

3. The process of shoemaking which includes the steps of cutting from a continuous strip of plastic material having latent rigidity equivalent to that of a wooden shank stiffener of substantially the same size a piece to fit the shank portion of the bottom of a lasted shoe which has been previously curved to a last bottom, rolling the piece so out upon the bottom causing it to adhere thereto and take the curvature thereof, and thereafter permitting the material to become so rigid-as to have substantially the rigidity of a wooden shank stiffener on the shoe bottom.

4. The process of giving permanent curvature and fullness to the shank portion of a shoe, which consists in conforming the insole of a lasted shoe to the curvature of a last bottom, molding a piece of plastic material having latent rigidity equivalent to that of a wooden shank stiffener of substantially the same size to the curvature of the shoe bottom at the shank portion, permitting the material to become so stiff as to acquire the rigidity of a wooden shank stiilener, uniting the molded material to the insole, and thereafter laying an outsole and uniting it to the molded material.

5. The process of shoemaking which includes the steps of applying plastic material having latent rigidity substantially equivalent to that of a wooden shank stiffener of the same size to the shoe bottom, and subsequently laying an outsole and attaching a heel by nails driven through the hardened plastic material in the heel seat.

6. The process of giving permanent curvature and fullness to the shank portion of a shoe, which consists in conforming the insole 01 a lasted shoe to the curvature of a last bottom, molding to the shank portion of a shoe bottom a piece of plastic material having latent rigidity substantially equivalent to that of a wooden shank stiflfener of the same size, molding said plastic material to fill the heel seat of the shoe within the overlasted margin of the upper, permitting the material to become so stiff as to acquire the rigidity of a wooden shank stifiener, uniting the molded material to the insole, uniting an outsole to the molded material, and attaching a heel by nails passing through the molded material in the heel seat.

KARL A. S'I'RITI'ER.

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