US2480078A - Process of shoemaking characterized by the employment of a special stiffener - Google Patents

Description

W. H. HEATON ET AL PROCESS OF SHOEMAKING CHARACTERIZED BY THE EMPLOYMENT OF A SPECIAL STIFFENER mg. 23, W49.

Filed Jan. 10, 1946 Patented Aug. 23, 1949 PRQCESS 0F SHOEMAKING CHARACTER- IZED BY THE EMPLOYMENT OF A SPE CIAL STIFFENER Walter H. Eeaton, Franklin, and Harry H. Straw,

Boston, Mass, assignors to Beckwith Manufacturing Company, Dover, N. H., acorporation of New Hampshire Application January 10, 1946, Serial No. 640,244

3 Claims. (c1. 12-146) Our invention relates to shoemaking and comprises an improved shoe stiffener, the process of makingthe improved shoe stiffener, and a process of shoemaking characterized by the use of our improved shoe stiffener.

The shoe stiffener of our invention is particularly adapted for use in conjunction with the general process of shoemaking which has come to be known in the trade as the California process. The salient features of the California process consist in uniting off the last an upper and insole, these elements being first carefully cut and marked prior to assembly so that in the process of stitching them together draft and fullness are imparted to obtain a properly shaped shoe. This is a departure from ordinary shoemaking methods in which the shape of the shoe is obtained by stretching an upper over a last, trimming oif surplus portions of the overlasted margin, and securing the upper to the insole while both members are in position on the last. In accordance with the California process a last is inserted after the upper and insole have been united for the purpose of shaping the shoe and also to hold it in shape during the operation of attaching an outsole.

It has long been thought that it was impossible to incorporateinto a California process shoe a toe stiffener or box toe of the conventional sort. In ordinary shoemaking a box toe stifiener is inserted between the lining and the upper before the shoe is lasted, and the stifiening and adhesive compound in the stiffener is activated when it is inserted. The subsequent lasting operations are carried out before the box toe becomes stiff, with the result that the stiffening of the box toe takes place while the shoe is on the last. During the stiffening process the box toe becomes adhesively united to the lining and the inner surface of the upper. In the California process the lining does not usually extend forwardly of the throat. Consequently if a box toe stiffener of conventional character were incorporated into the structure of the shoe and activated prior to the insertion of the last, the box toe would adhere not only to the upper but also to the surface of the last, and the withdrawal of the last would be impossible.

We have discovered that it is possible to produce a shoe stiffener which can be successfully incorporated into a shoe manufactured according to the California process. A shoe stiffener capable of such use involves a novel process for manufacturing the stiffener, as well as a novel method of employing it in the shoemaking process.

The most important object of our invention is to improve the quality and appearance of the California type shoe by the incorporation therein of a shoe stiffener.

Another object of the invention is to provide a process in which it is possible to activate a shoe stiffener secured within an upper in such condition that it is exposed on the interior of the shoe and. at the same time render it possible to insert and withdraw a last without causing the shoe stiffener to become cemented to the last.

In one aspect our invention comprises a fibrous shoe stiffener saturated through approximately one half only of its thickness with a stifiening and adhesive compound, while the other half and one surface thereof is left relatively soft, flexible and porous.

In another aspect our invention comprises a shoemaking method including the step of introducing an activating agent through a porous and flexible portion of a shoe stiffener to a layer thereof saturated with a stiffening and an adhesive compound disposed against the inner surface of a shoe upper.

These and other objects and features of our invention will be more readily understood and appreciated from the following detailed description of a preferred method for producing our improved shoe stiffener, together with a description of a preferred manner of incorporating the improved stiffener into the structure-of a. shoe, the same being illustrated in the accompanying drawing, in which I Fig. 1 is a diagrammatic view in cross section suggesting the manufacture of our improved shoe stiffener, the elements therein. being shown on an enlarged scale,

Fig. 2 is aplan view of a stiffener made in accordance with our invention, and

Fig. 3 is a View in cross section through the toe end of a shoe including in its structure our improved stiffener.

Referring more particularly to Fig. l, the shoe stiffener of our invention is preferably produced by first providing a sheet of double napped fiannel, although single napped flannel, felt with a lofty pile, or other similar fibrous sheet material may be substituted with little effect on the results. As used herein, the term nap or napped" refers to any fibrous material of which one surface is covered with relatively long fibers or filaments free at one end and anchored at the other end to the material. For purposes of illustration we have shown in the drawing a sheet I0- of double napped flannel. The first operation is to feed the sheet I between a pair of rollers i2 and I4. The roller [2 is continuously supplied with a film l6 of a stiffening and adhesive compound. There is a wide range of materials suitable for the purpose, such as solvent-softening lacquers and cements including 'nitro-cellulos'e compounds, vinyon, ethyl acetate, ethyl cellulose, and materials soluble in ketones, alcohols and other organic solvents. Another type of compound comprises the water soluble gums, starches or resins. For example, polyvinyl alcohol, sodium carboxymethyl-cellulose, British gum, gum arabic and corn starch are all materials capable of use in the process of our invention. Furthermore we contemplate the use of thermal setting compounds such for example, as bakelite or one of the melamines. The foregoing list ofcompounds is to be taken as suggestive of a few suitable stiffening and adhesive compounds. Others, equally useful, will suggest themselves to those skilled in the art as equivalents of those above mentioned.

One specific water-softening compound that may be employed with good advantage is a mixture of two parts dextrin, one part corn starch andone part pearl gum. The ingredients are mixed in a small quantity of cold water and then poured into a suitable volume of hot water. After thorough mixing, the compound is ready to be used incarrying out the process herein described. ""The' l'owerroller I4 is dry and serves merely to support-and feed the sheet Ill. The action of the rolls 1'2 and I4 is to load the compound I6 into one surface of the sheetlfl and to saturate the sheet '10 through approximately one half of its thickness; loading, the sheet I 0 is fed through the rollers so that the loading takes place against the direction of the nap. The upper map of the sheet [0 is shown at I8 and the lower nap suggested at 20.

The-extent of the penetration of the compound lfijintothe sheet I!) is ofcourse partially determined by the pressure exerted by the rolls I2 and M on the sheet If! and may be varied by adjusting their spacing. However, it is easily possible to secure an adjustment-which will cause the compound IE to penetrate approximately'through one half the thickness 'of the sheet Ill, and we have discovered that this amount of penetration is suitable in'practic. The other half of the sheet is' left soft and porous.

From thelo'ading operation described above the sheet I0 is passed through a drying tower in which the solvent is evaporated leaving a relativelystiff, dry deposit of the compound in the sheet. "After the drying operation has been accomplished'the'sheet is passed through calender rolls adjusted to compress it toproper thickness. Subsequently the sheet may be dried out in blanks suitably shaped for shoe stiifeners. The final operation is to skive the edges of the stiffeners so that they will blend easily with the surface of the upper of the shoe and not leave uncomfortable or unsightly ridges. The skiving, of course, is carried out from the unsaturated surface of the shoe stiffener. The finished stiffener exhibits one surface which is relatively soft, flexible and porous, being entirely suitablefor incorporation into an unlined shoe.

In Fig. 3 there is shown a partially constructed shoe including an insole or platform sole 26 to the marginal edge of which is stitched the out-turned margin of an upper 28, with one of our improved stiffeners 3U caught in the stitching 32 which united the upper and the insole. The usual binding strip 34 is sewn to the margin of the assembly In order tosecure such saturation and :3

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4 by a line of stitchilng 36. The stiffener 30 is secured with its coated surface against the inner face of the upper 28, and the inner untreated surface of the stiffener 30 is exposed in the interior of the shoe.

We refer to the untreated portion of the stiffener as soft and flexible in the sense that the treated portion is relatively hard and stiff, and the expression soft and flexible is hereby defined for the purposes of this specification and the appended claims as covering any portion or surface of the stiffener which has a character of such nature that it may be used as an exposed surface next the foot of the wearer in the interior of the shoe.

Before the last is inserted in the shoe the saturated portion of the stiffener is activated by introducing into the interior of the shoe an agent to activate the stiffening and adhesive compound. For stiffeners impregnated with a soluble compound a solvent may be sprayed against the untreated surface from a goose-neck nozzle 38 introduced into the interior of the shoe adjacent the stiffener. Thesolvent easily penetrates the untreated porous portion .of the stiffener 30 and activates the stiffening andadhesive compound loaded into the unexposed surface thereof. Obviously the solvent may be swabbed on the stiffener instead of being sprayed. Where a thermal setting stiffening and; adhesive compound has been used, the entire shoe may be heated, or a blast ofsteam or hot air introduced into the interior thereof. In any case the'activation of the compound is followed by the insertion of the last. The lastpresses the temporarily flexible stiffener against the inner surface of the .upper 28 and cements the two together; While the last is in place, a midsole or outsole is secured to the bottom of the shoe, and the last is then withdrawn. During the sole attaching operation and while the, last is in the shoe, the solvent, evaporates to leave the stiffener 311 molded to shape and relatively stiff and hard. Inasmuch as there is no stiffening compound in contact with the surface of the last, withdrawal of the last isnot impeded. The resulting shoe will-present an appearance and quality every bit as fine as that obtained in the toe end of a shoe manufactured by conventional methods.

.It is to beunderstood that the shoe manufacturing process above described merely illustrates one of a great number of ways in which our improved stiffener may be incorporated into the structure of a California process shoe. The details of upper and sole structure may be varied at will, and the introduction of the activating agent may beaccomplished in any suitable mantogether off the-last an upper, an insole and said stiffener, the saturated half of said stiffener being disposed against the inner surface of the upper, introducing a solvent through the soft flexible half of the stiffener to the saturated half thereof, inserting a last to shape the shoe and press said stiffener against said upper, permitting said solvent to evaporate, and Withdrawing said last.

2. A process of shoemaking which comprises providing a shoe stiffener saturated on one surface with a stiffening and adhesive compound and porous and flexible on the other surface, assembling and uniting 01f the last an upper, an insole, and said stiffener, the saturated surface of said stiffener'being disposed against the inner surface of said upper, introducing an activating agent through the soft flexible surface of the stiffener to the saturated surface thereof, inserting a last in the shoe to press the stiffener against the upper and cement it thereto, and withdrawing the last.

3. A process of shoemaking which includes the steps of providing a box toe stiffener saturated on one surface and loaded throughout approximately only one-half of its thickness with a stiffening and adhesive compound and being porous and flexible on its other surface, assembling and uniting off the last a vamp, an insole and said stiffener, the saturated surface of the stiffener being disposed in contact with the inner surface REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 559,618 Seaver May 5, 1895 749,267 Davis Jan. 12, 1904 1,191,315 Johnson July 18, 1916 1,678,139 Furber July 24, 1928 1,982,725 Clark et a1. Dec. 4, 1934 2,063,690 Lovell Dec, 8,1936 2,332,501 Austin et a1 Oct. 26, 1943 2,414,104 Kamborian Jan. 14,1947

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