US 2003961 A
Description (OCR text may contain errors)
June 4, 1935. M. J. VITTENGL 2,003,961
INNER SOLE AND LIKE PRODUCT Filed July 5, 1932 Morgan I VittcngI Qwuww Patented June 4, 1935 UNITED STATES PATENT OFFICE Morgan J. Vittengl, Fairfield, Conn., assignor to E. I. du Pont de Nemours & Company, Wilmington, Del., a corporation of Delaware Application July 5, 1932, Serial No. 620,908
2 Claims. (CI. 36-43) This invention relates to a method of enhancing the pliability of sheet material, and more particularly to the manufacture of improved innersoles.
As well understood by those familiar with the requirements of materials for shoe construction, the innersole should be flexible in the direction along the length of the. foot so as to offer the minimum of resistance to the normal flexure of the foot during walking. The innersole must also be rigid across the width of the foot in order to adequately protect the foot and also to prevent bulging or buckling of the shoe during the process of manufacture. Briefly, the requirements for an innersole are that it should be flexible from heel to toe and rigid from ball to ball. A material having these characteristics is said to have differential pliability. Inasmuch as the same requirements hold for other forms of shoe soles such as middlesoles, it will be understood that the reference to innersoles herein is meant to include middlesoles as well as the innersoles.
This invention has as an object a method for improving, regulating or developing the proper differential pliability in those sheet material products in which such property is desirable. Another object is an improved innersole in which the difl'erential 'pliability is regulated so as to yield the desired ratio between flexibility and rigidity. Other objects will appear hereinafter.
The objects of the invention are accomplished by means of an embossing process whereby a pattern of definite character is imprinted into the material under treatment. The embossure is characterized by line characters so grouped as to produce the maximum breaking or embossing of the material across the width of the material and a minimum of marking or embossing along the length of the material. By this treatment the material has greater pliabilityin the direction of the closely grouped lines than in the direction of the less closely grouped lines.
My invention, which is of peculiar advantage in the manufacture of innersoles, will be better de-.
scribed in connection with the accompanying drawing in which the single figure is a diagrammatic representation of an innersole or a middlescle. I
In this figure the line AA represents-the direction known as heel to toe, and the line BB designates the direction transversely of the sole.
The preferred method of practicing my invention consists in forming the innersole from a fabric base, preferably from sheet material consisting of felted paper making fibers, and impregnating the fabric with rubber latex to a rubber content of from 15% to 50% based on the total weight of the finished product. I then form lines on the rubber impregnated material by pressing it against a rectangular mesh wire 5 screen so that the depth of the impressed lines is within the approximate range of .005 to .01 in depth. Good results are obtained by pressing the rubber impregnated material between two 4 x 26 mesh screens arranged so that the pattern on the upper and lower surface of the material under treatment is identical. The screens are so arranged that the more closely spaced embossed lines run transversely of the sole as indicated by the line BB in the drawing and the less closely spaced linesrun in the heel to toe direction as indicated by the line AA in the drawing. The pressing may be eifected in any well known manner such as by hydraulic presses, jack or cam presses, rollers, etc. After the embossing operation just described the innersole becomes markedly more flexible in the direction of the closely grouped lines (26 lines to the inch) while it does not change appreciably in flexibility in the remotely grouped line (4 lines to the inch) direc tion. By this means the desired effect of differential pliability or flexibility from heel to toe and rigidity transversely of the sole is conveniently effected. 30
In order to accomplish the purpose of the pres- .ent invention, there must always be lines in the direction of BB in the drawing although lines in the direction of AA may be omitted. It is highly desirable, however, to have some lines in the direction of AA to control the wrinkling known as piping caused by the concave bending of the material, and thus contribute to the comfort of the shoe, but the number of heel to toe lines should not be enough to affect the cross rigidity of the 40 innersole.
While a textile fabric base or felt may be used in the manufacture of innersoles as described above, it is preferred to use an absorbent paper or felt as the impregnating base. Particularly I side of the material and leaving the other side smooth or embossing with a diiIerent characteristic.
The invention is not limited to the specific embossed design mentioned above but may be carried out with line embossing characteristics ranging from no lines in the remotely grouped line direction and a single parallel line embossure running across the width of the innersole to any number of lines that may be required to give the degree of differential pliability desired.
The invention, while of a special utility in the manufacture of innersoles, is also useful generally to improve the differential pliability of sheet material and to impart this characteristic to materials which do not possess any differential pliability; that is, materials which are as stiff across the width as they are along the length. As a somewhat less advantageous practice of the invention, there may be mentioned the substitution of a cheap leather for the impregnated fabric base described above.
As many apparently widely different embodiments of this invention may be made without departing from the spirit and scope thereof,'it' is to be understood that I do not limit myself to the specificembodiments thereof except as defined in the following claims:
1. A shoe sole having closely spaced lines impressed therein and running transversely of the sole and impressed lines running in the heel to toe direction of the sole, said last mentioned lines being further spaced than said first mentioned lines.
2. The shoe sole set forth in claim 1 in which said lines are impressed to a depth of from about .005 to .010 inch.
MORGAN J. VITI'ENGL.