US1739578A - Shoe stiffener - Google Patents

Description

Dec. 17, 1929. A. L. CLAPP SHQE STIFFENER Filed Sept. 12. 925

to saturate the fibrous material with glue and Patented Dec; 17, 1929 UNITED STATES PATENT OFFICE ALBERT L. 'CLAI'I', OF DANVER-S, MASSACHUSETTS, ASSIGNOR TO BECKWITH MANU- FAGTURING COMPANY, OF BOSTON, MASSACHUSETTS, A CORPORATION OF MASSA- GHUSETTS- SHOE STIFFENER Application filed September 12, 1923. Serial No. 662,223.

Shoe stiffeners are commonlyconstructed of fibrous sheet material saturated with thermo-plastic material, that is, material which is hard at atmospheric and body temperatures but which may be softened by subjecting it to a moderate degree of heat. The

shoe stiflener is heated when being formedinto the shoe and thereafter being allowed to cool in proper shape, becomes stiffand rigid and so normally remains during the life of the shoe. The thermo-plastic material is frequently softened by the application of dry heat and it is often found that when shoes having incorporated therein stifieners saturated with such material are exposed to the sun, as for example whenondisplay in show windows, the relatively intense heat causes the material 'to soften sufficiently to permit the stifieners partially to collapse, thus impairing both the appearance of the shoes and terial other material which may be softened only by the application of moist heat thereto, such material, for example, as water soluble gums or stiffening agents such as animal or fish glue. It has beenfound impracticable also with the tremo-plastic material. The

glue when used alone does not possess properties necessary for its successful use as stiffenmg materlal for the fibrous base, slnce 1t 1s easlly cracked and pulverized andis not waterproof. It is found, however, that a from the opposite face throughout and covers the glue.

Referring to the accompanying drawing which conventionally illustrates, much enlarged, a piece of the finished material, the

felt sheet is indicated at 1, the .coating of glue applied to one face thereof and penetrating more or less between the adjacent fibers of the felt at 2, and the thermo-plastic saturant permeating the felt at 3 and coating the glue surface at 4.

It is found in practice that the portion of the material saturated and coated with the .glue vis sufficiently stiff to cause the' shoe stlfiener formed therefrom to retain its shape even when subjected to dry heat sufficient to soften the thermo-plastic compound and to cause the stiffener, without the presence of the glue, to lose its shape. But by subjecting the stiffener so treated to the action of both moisture and heat, the glue, together. with the thermo-plastic material, is softened so that,

the stiffener is reduced to a limp or plastic condition where it can be successfully worked and shaped to the last.

Instead of animal glue, dextrine, starch, or other water soluble gums may also be used, but animal or fish glue has been found preferable. The presence of the thermo-plastic material also renders the stiffener waterproof, 'which it would not be by the use of glue alone, but the glue coating is covered with the thermo-plastic material in the saturating process and so is sufficiently protected to render it waterproof without causing it to be entirely inaccessible to the moist heat treatment to which it is subjected preparatory for the forming operation about the last. Where the glue is used, Montan wax may be employed as the thermo-plastic-saturant for a felt such as produced on a paper machine. Montan wax ordinarily can not be used satis= factorily alone in the impregn ation of apaper felt where glue is not used, since it becomes so fluid, when heated sufficiently to soften it that it acts as a lubricant and permits the fibers of a felt, such as produced on a paper machine, to pull apart. The presence of the glue, however, holds the fibers together and retains the wax and so make it possible to use this material alone as the thermo-plastic saturant.

By the treatment herein outlined, it "is seen that two stiffening agents of different characteristics, one being softenable by dr heat and the other requiring moisture in a dition to heat, are employed in different ortions of the thickness of the fibrous s eet material, each responding to heat treatment in its own way without modification by the other. One of these stiffenin heretofore described, may be incorporated while in an aqueous vehicle, the water then being dried out and this agent allowed to harden. The other agent ma then be incorporated when in melted con ition. In the completed 'article the stiffness imparted by. each agent is reducible under its own particular conditions of softening independently of the other 'so that the stiffener must be subjected to the conditions which will soften all the stiffening agents used in order to render it limp.

I claim:

1. A shoe stiffener comprising fibrous sheet material having one portion treated with a water soluble stiffening agent only and anotlier portion with thermo-plastiematerial on y.

2. A shoe stiffener comprising fibrous sheet materialpartially stiffened by a water soluble stiffening agent applied to one side and adapted to be softened by moist heat and saturated with thermo-plastic material.

3. A shoe stiffener comprising fibrous material stiffened by a water soluble stiffening agent and a thermoplastic agent, one of said agents enveloping the other.

4. A shoe stiffener comprising fibrous material having one portion saturated with a water soluble stiffening agent only and another portion saturated with a thermoplastic agent only.

5; A shoe stiffener comprising fibrous sheet material having a portion treated with a water soluble stiffening agent, and thermoplastic material enveloping said treated portion and saturating'the remainder of said material.

6. A shoe stiffener comprising fibrous sheet material, a water soluble stiffening agent applied to one face of said sheet material, and a thermoplastic enveloping said water soluble agent and with which said fibrous material is saturated,

. 7. A shoe stiffening comprising fibrou sheet material partially stiffened by .a water soluble material and saturated with thermoplastic material.

8. A shoe stiffener comprising fibrous sheet material coated on one face with glue, and

saturated with Montan' wax.

9. A shoe stiffener com material coated on one ace with glue, and

agents, as

rising fibrous sheet Saturated with Montan wax, the wax also coating the glued face. it

10. A shoe stiffener comprisin .fibrous sheet material partially saturate with a water soluble stiffening agent and then saturated with thermo-plastic material. 11. A shoe stiffener comprising fibrous sheet material saturated throu h-a portion of its thickness with a water so uble 'stiffening aglent, and'then saturated throughout with t ermo-plastic material.

12. In the manufacture of shoe stiffeners the steps which comprise coating one face of fibrous sheet material with a water soluble stiffening agent, and then immersing the sheet in melted thermo-plastic material.

13. In the manufactureof shoe stiffeners, the steps which comprise coating one face of fibrous sheet material with glue, permitting the glue to dry, and then saturating thematerial and coating the glued face with thermoplastic material.

14. In the manufacture of shoe stifl'eners, the steps which comprise partiall saturating fibrous sheet material with a sti ening agent softenable only when subjected to a solvent, permitting the material so treated to harden, and then further saturating the material with a sltliffening agent softenable when subjected to eat.

. 9 15. In the manufacture of shoe stiffeners, a

signature. A I

ALBERT L. 'GLAPP.

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