US2210753A - Shoemaking method - Google Patents

Description

Aug. 6, 1940. w,` p, FIELD v 2,210,753

sHoEMAxING METHOD Filed Jan. 19, 1937 z sheets-sheet 1 nun nuff' I 770621Z@ Wauw new Patented Aug. 6, 1940 UNITED STATES PATENT OFFICE f p snoEMAKT'NG METHOD Walter Field, Brockton, Mass.

Application January 19, 1937, Serial No. 121,258 p a claims. (c1. 12-142) f row of edge stitching, which, in addition to fas- This invention relates to the manufacture of shoes and more particularly to an improved shoe and to a process for making the same.

The main object of my invention is the provision of a cheap shoe having both inside and outside the appearance of genuine Goodyear welt shoe and having the durability and Ywearing qualities of a shoe of that character, and the provision of a method for making the same.v p

Another object of my invention is the provision of a cheap shoe of the welt type, which mayhave either a leather outer sole or one of rubber composition or similar material.

Another object of the invention is the provi- 1'. sion of a method by which a strong, erlicient and durable bond between the outer sole and the shoe upper is secured by the vulcanization to the upper of a Ywelt of vulcanizable material, lwhich is permanently attached to the outer sole.

An additional object ofthe invention' is the provision of a simple method for making shoes which eliminates many of the steps heretofore considered necessary in the making of welt sho-es Vand which materially shortensthe time consumed in the production of the shoesy and materially reduces the cost thereof.

Other objects of the invention will be more particularly set forth and described hereinafter.

My invention contemplates a shoe and method of making the same, in whichk the ,louter sole is permanently fastened to the upper by vulcanization thereto of a Welt, which is permanently attached to the outer sole. This. is accomplished by impregnating the roughened bottom edges of the upper with vulcanzable material, such as rubber latex, containing vulcanizingagents, and

by using a welt of vulcanizable material, such as rubber composition. These parts are then 'coated with a solution made up of one or more'vulc'ani'z'- ation `accelerators. dissolved in solvents capable of dissolvingthe said vulcanizable material, and, after a short interval of time, the coated surfaces are pressed together under a heavy pressure which is maintained fora suiiicient time to permit lvulcanization to take place.

In this manner, a rm and lastingbond is secured between the welt and the upper, due to the fact that the vulcanization results in an integral bonding body ofvulcanized material which permeates and becomes an integral part of both the attached portions, so that they cannot be separated without rupturingione or the other of the erably, the weltis attached to the outer sole `by .a

teningthe two parts together, has the advantage of a Goodyear welt shoe. The Welt, however, may be attached to the outer sole in any suitable manner, either by vulcanization by the same method pursued in attaching the welt to the upper, or it may, in some cases, be attached by cement, where the welt and the outer sole are of materials such as rubber composition, which permit the use of cement.

In the embodiment of the invention described hereinafter, rubber is designated as the preferable vulcanizable material used for attaching an outer sole to a shoe upper by vulcanization. This requires, of course, that ythe vulcanization accelerators used be adapted for dissolving rubber. It is to be understood, however, that my invention is not to be limited to the use of rubber AasA the vulcanizable material, since there are other vulcanizable substances which may be used in 1p-lace of rubber, and ,other solvents especially adapted for those vulcanizable materials. In any event, however, the welt must, in such case, be

made 'of the same vulcanizable material that is used-for `impregnating the 'edges of the lastedl upper. :In the accompanying drawings illustrating my invention, Figure 1 is a side elevation of la mans shoe constructed in accordance therewith;

Fig. 2.is a bottom plan view on an enlarged scale of a lasted upper and inner sole having the .surplusmaterial trimmed off, with the edges: o-f

receiving lposition;

Fig. 6 is a cross-.sectional View of. the welted soler unitA shown inFig. 4;

l Fig. 7 is a similar View shown inFig. 5; and 1 Fig; 8 is aside elevation of `a portion of the ofthe welted sole vunit Welt. i

.In the drawings, my invention is shown vas .exemplified in a mans Oxford shoe of the welt type, but it is to be .understood that this is merely for the purpose of illustration and that the invention -is also applicable to thel manufacture of womens and childrens shoes, and, generally, to

kthe:1`nanufacture of all kinds of footwear coming Vunclerthe generic term shoe As shown, the

shoe comprises an upper designated generally as I, an inner sole I2, an outer sole I4, and a heel I6. The upper, which may be made in any suitable manner, is shown as comprising outer parts consisting of av pair of quarters I8, a vamp 20, and a tip 22, andinner parts include a lining 24, a box toe 20, and a heel'counter 28. The outer sole I4 is provided with a welt 30 fastened thereto.

In the method of making a shoe according to my invention, the shoe upper is first prepared in the usual manner by assembling and fastening the various parts thereof in their proper relations, after which the inner sole I2 is tacked to the last and the prepared shoe upper I0 is fitted over the last ready for the pulling-over operation. The upper is then lasted, and this may be done by any suitable McKay method of lasting, either full cement lasting, step-by-step nail lasting, or staple lasting. A combination of the cement and staple methods is preferred for the lasting operation, and, in carrying this out, the bottom edges and the margin of the outer face of the inner sole are coated with any suitable cement, and the edges of the upper are then pulled over and adhesively fastened to the inner sole, and the sides of the upper are staple-lasted with staples 34 to the inner sole by the Well-known Littleway process. In the latter process, the staples are of light construction and are clenched within the inner sole without going through and appearing on its inner surface. Around the toe, the pulledover edges of the upper may be temporarily held in place to permit the cement to set, by pull-over tacks inserted in the toe portion of the last. The edges of the upper around the heel are preferably lasted by the use of permanent tacks 36, but these edges may be lasted by adhesive alone if desired. After the cement has thoroughly dried or set, the pull-over tacks are withdrawn and the surplus material of the upper, including the box toe and lining around the toe portion of the last, is trimmed off to provide a smooth, flat surface, as shown in Figure 2. The exposededges of the outer leather-parts of the shoe upper are then scoured or roughened in preparation for vulcanizing the outer sole thereto.

Mymethod also includes the preparation of an outer sole unit, comprising an outer sole I4, which may be of leather, rubber composition, or other suitable material, and a welt 30 of vulcanizable material permanently attached to the outer sole. In the preparation of this unit, the kouter sole is died out of suitable material to the exact form and dimension required by the last and is prepared in the usual way. The welt is preferably made of molded rubber composition and may be made in various forms, but, preferably, its outer edge portion, which is exposed in the finished shoe, is of uniform thicknesswith parallel top and bottom faces, and its inner edge portion is 'beveled on its top face, and the width of the beveled portion 32, although it may be varied to suit varying conditions, must be sufficient to insure a strong and durable bond between that portion of the welt and the edges of the shoe upper when those parts are fastened together by vulcanization. The welt is applied around the margin of the forepart of the sole from the heel breast on one side to the heel breast on the other side, and is permanently fastened to the outer sole by any suitable means, such as stitching 40.

It is important that the welt be sufficiently tough to hold the'stitching by which it is fastened to the outer sole and that it be of sufficient hardness, approximately between and 92, in order to retain its form and shape permanently, and that it be susceptible to chemical agents adapted to dissolve rubber and to further vulcanization. Although the Welt may be made of various rubber compositions, yet I have found that a composition made according to the following formula gives most excellent results and produces a welt which fully answers the foregoing requirements. This composition is made up of the following ingredients and parts by weight:

Parts Crude rubber in smoked sheets 27 Automobile tire reclaim 24 Inner tube reclaim 7 Mineral rubber compound 2 Carbon-X 9 Vulcanization accelerator (DPG) 1.7 Carbon black 25.5

R-Kadox 2 VGB'I 1% Sulphur 1.7

The mineral rubber compound is a natural deposit which is used as a filler and a substitute for rubber and is a commercial product well known under the name MRX; the Carbon-X imparts toughness to the composition and is a well-known commercial product; DPG is a trade name for a well-known vulcanization accelerator used with sulphur for that purpose; R-Kadox is a zinc solution used for hardening and is likewise well known under that name; VGB` is an anti-oxygen agent to retard oxidizing and is well known under said designation; and carbon black is used for imparting toughness and rigidity to the compound, and, at the same time, produces its black appearance.

The welt is formed from the composition by molding and is vulcanzied under heat and pressure for from ten to fifteen minutes, so that when it is taken out of the mold, it is not entirely cured but is still subject to further Vulcanization.

In attaching the Welt to the outer sole, I prefer to use a single line of welt stitching 40, which is located in the outer portion of the welt so as to be Visible in the finished shoe. The stitching 40 may be either of the well-known lock or chain forms. When the lock stitching is used, it may be left exposed on the outer face of the outer sole, or it maybe laid in a narrow channel cut in the outer face of the sole and covered by a turned-back portion; but in the case of chain stitching, it is preferable to form a channel in parts of cleaned liquid latex 40 to 50% rubber content.

part colloidal zinc oxide.

0.4 part colloidal sulphur, and

0.75 part of a solution consisting of 3 parts of casein (fat free) 6.2 parts of sodium sulphide 0.08 part of sodium salicylate 14.72 parts of distilled water.

The viscosity of this liquid Yat 20 C.

(Englers method) is 1.5`

This Solutionshould be liberally applied to the roughened surfaces and brushed in so that ,it

will penetrate the edges of the upper thoroughly.

c More than one coating may be applied, but each coating must be allowed to dry thoroughly before the next coating is applied. Normally, a coating will dry in about half an hour. This step of my process may be carried out some days in advance of the next step, since the material in the impregnated edges of the upper is not affected by aging for a period of two months or more.

After the edges of the upper have been thoroughly permeated with the latex mixture and have dried, the next step in my process consists in treating those edges and the welt with a solution containing one or more vulcanization accelerators dissolved in solvents capable of dissolving rubber. One solution which is adapted for this purpose comprises the following:

1 part of rubber. 99 parts of trichlorethylene.

l part of an accelerator such as a powder made up of 10 parts of ordinary commercial piperidine l0 parts of dithiocarbamate l0 parts of carbon disulphide 50 parts of china clay.

This powder is similar in composition to what is sold on the market under the name Superac.

This solution is applied in any suitable manner to the impregnated edges of the upper and to the beveled portion of the welt, which is previously roughened up to remove the hardened film due to molding and to expose the softer interior. A sufficient amount of the solution should be used to soften up the rubber in the edges of the upper and the welt to an appreciable depth and more than one coat may be applied if necessary. After being coated, the parts are allowed to stand for from five to ten minutes until the rubber contents have been partially dissolved and softened, after which the welted sole unit is applied to and spotted on the lasted upper and the parts are subjected to a pressure of at least eighty-live pounds to the square inch for a period of from twelve to twenty minutes.

The pressure is preferably applied by suitable mechanical means and a higher pressure than that specified is of advantage. My experience has been that the higher the pressure and the longer it is sustained within reasonable limits, the stronger is the bond between the welt and the upper.

Under this pressure, the accelerators in the last solution penetrate throughout the rubber in the edge of the upper and the welt and start cold vulcanization which unites in one integral homogeneous body the rubber content present in both parts and securely locks the welt to the upper.

After the shoe is released from the pressure, the heel portion of the outer sole is then nailed around the heel in the usual manner, after which the heel may be applied thereto. The edges of the outer sole and welt may then be trimmed and set, or, if preferred, this operation may be performed before the welted sole unit is fastened to the shoe upper. After this, the shoe is subjected to such furthen finishing operations as required.

In Figures 5 and 6 of the drawings, the shoe is shown as made with a ller 42, but it may be made without a filler. Any suitable filler may be used, such as a thin, firm, felt filler, which I have found gives the best results, and this filler isl preferably applied to the shoe upper directly after it is lasted.

My method can be used not only with uppers having leather outer parts, but also with uppers in which the outer parts are of canvas or other fabrics or other material of a fibrous character capable of being permeated by a solution of vulcanizable material.

Some of the important advantages of my invention are that it eliminates many of the costly operations now involved in producing a genuine Goodyear welt shoe and simplifies the process to an amazing extent; that it leliminates the rough inside of theMcKay made shoe, whether produced by lock stitching or other variations of the McKay system; and that it further eliminates the stiff midsole, which is characteristic of the McKay welt and nailed shoes, and, consequently, results in producing a more flexible and resilient shoe than any produced by either of the systems mentioned above. In short, my invention permits the production of a shoe having 'the appearance, both inside and out, the durability and wearing qualities, and other advantages of high-grade Goodyear welt shoes at a production cost of cheap shoes.

One of the advantages in using a welt of rubber composition, or similar moldable material, is that the exposed face of the welt may be provided with transverse corrugations 44 more closely simulating the appearance of a Goodyear welt, as shown in Figure 3, which corrugatons may be formed in the molding process, and, therefore, are permanent and are not affected by Wear. The same indentations in a leather welt disappear with the absorption of moisture by the leather, so that the welt in time becomes comparatively smooth.

Another important advantage which flows from the use of my invention in shoes having rubber composition soles is that the soles may be made of a color to harmonize with the color of the shoe upper. During the past few years, there has been a growing tendency in the shoe manufacturing industry to produce shoes having uppers of all `shades of color. This tendency, which has heretofore been largely confined to womens shoes, is now spreading to mens shoes, and it not only includes uppers of different colors, but also combinations of different colors in the same shoe. Attempts have heretofore been made tocarry out these color schemes in shoes having leather soles by painting the soles and the' welts, if provided with welts, or by coating them with a veneer. This has not proved satisfactory, however, because the paint or veneer soon wears off and disappears. Rubber composition, however, can be made in any color, and soles and welt of this material can be made to match exactly the color of the shoe upper, or can be made of a different color in harmony with the color of the shoe upper, and the color of the sole and Welt is permanent. The coloring of rubber composition is done in the mixing and molding of that material, so that there is no appreciable increase in its cost, whereas, the coloring of a leather sole and a leather Welt involves additional operations which increase the cost of the shoe.

Another important advantage of a shoe constructed by my method is that it is substantially waterproof, because the joint between the edges of the upper and the welt is closed by a body of vulcanized rubber, which is integral with the edges of the upper and the welt, and, thereby,

effectually prevents the entrance of moisture.

Although I have described herein, as a part of my invention, the attachment of the Welt to shown in Figs. 5 and 7 of the drawings, and

Where in the claims the Welt and outsole are defined as attached one to the other, this language is intended to cover such integral construction of a sole unit having a Welt portion and an outsole portion.

It is to be understood that my invention is not to be limited to the precise forms herein shown and described, since it may be embodied in various other forms, all Within the scope of the following claims.

What I claim is:

1. A method of making shoes consisting in lasting an upper over the marginal edges oi an inner sole, roughening the lasted edges of said upper and then impregnating them with a vulcanizable material containing a vulcanizing agent, attaching a partially vulcanized Welt of vulcanizable material along the margin of an outer sole, said Welt having an inner longitudinal beveled portion of substantial Width equaling the Width of the lasted edges of said upper, coating said impregnated lasted edges of said upper and the beveled portion of said welt with a solution containing a vulcanization accelerator dissolved in a solvent capable of dissolving said Vulcanizable material of said Welt and said edges, and then placing said outer sole against said lasted upper and subjecting said parts While in tacky condition to a heavy pressure continued for a sufficient time to vulcanize said Welt to said lasted edges for fastening said outer sole to said upper.

2. The method of attaching to a lasted upper a Welt having an inner longitudinal bevelled portion of vulcanizable material which method consists in roughening the lasted edges of the upper and then impregnating them with a Vulcanizable material containing a vulcanizing agent, coating said impregnated edges and the bevelled portion of the welt with a solution containing a vulcanizing accelerator dissolved in a solvent capable of dissolving the vulcanizable material of the Welt and edges, positioning the bevelled portion of the Welt against the lasted edges of the upper, and subjecting the parts While in a tacky condition to a heavy pressure continued for a suicient time to vulcanize the Welt to the lasted edges of the upper.

WALTER P. FIELD.

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