Tread surface for footwear

April 18, 1939.

Η. T. KRAFT

TREAD SURFACE FOR FOOTWEAR . Filed April 1, 1936

2,155,166

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ATTORNEYS

Patented Apr. 18, 1939

2,155,166

UNITED STATES PATENT OFFICE

2,155,166

TREAD SURFACE FOR FOOTWEAR

Herman T. Kraft, Akron, Ohio, assignor to The General Tire &amp; Rubber Company, Akron, Ohio, a corporation of Ohio

Application April 1, 1936, Serial No. 72,020

Claims. (Cl. 36—59)

This invention relates to tread surfaces for footwear and particularly to soles and heels for footwear, and among its objects is the provision of new and improved soles and heels which will 5 have a maximum frictional contact with the floor or other surface, which will be extremely resilient and furnish a cushioning effect for the wearer, and which will be simple in design, inexpensive to manufacture and of long wearing 1θ qualities.

Other objects will become apparent from a study of the specification and the drawing, In which:

Figure 1 is a side elevation of a shoe embody15 ing the sole and heel construction of this invention;

Fig. 2 is an enlarged bottom view of the same shoe;

Fig. 3 is a section on the line 3—3 of Fig. 2; ²⁰ Fig. 4 is a section on the line 4—4 of Fig. 2;

Fig. 5 is a section, similar to that shown in Fig. 3, of a modification of the sole configuration of this invention;

Fig. 6 is a modification of a sole construction ²⁵ with the ribs or vanes concentric; and

Fig. 7 is a modification of a heel construction corresponding to the sole construction of Fig. 6.

Briefly, my invention is embodied in soles or heels of molded rubber in which a plurality of ³⁰ closely spaced parallel or concentric, flexible and elastic finlike ribs of materially greater depth than width are employed. While the ribs are individually relatively weak and flexible, they are sufficient in number to carry the loads to ^3:5 which they are normally subjected without substantial distortion. The ribs, however, provide an elastic cushion between the body of the sole or heel and the ground surface, which will yield in any direction under frictional thrusts exerted 40 on the ground engaging edges of the ribs. The rubber in the traction surface of the sole or heel is maintained soft and pliable under all conditions of load and this greatly increases the adhesion of the sole or heel to the surface walked 45 upon. It is this greatly increased non-skid capacity of the sole and heel that renders the invention particularly useful In connection with athletic shoes.

Referring to the drawing by numerals of ref50 erence, 10 designates the sole and it the heel respectively of a shoe 12. In a preferred embodiment of my invention the sole (0 has a plurality ef ribs 13 of finlike construction, separated by narrow grooves, or spaces 20, giving 55 the bottom of the shoe a deep fluted appearance.

As shown in Fig. 2 these ribs are generally parallel to one another and extend substantially the ¹entire length of the sole. In order to obtain a maximum frictional effect combined with great resiliency, it is important that these ribs be of 5 substantially greater depth than thickness as shown in Figs. 3 and 5. Around the periphery of the sole is a binding strip 14 which may be formed integrally with the sole, as shown in the drawing, and the ribs 13 may be joined to it 10 at their extremities. The body portion 15 of the outer sole which is fastened to the upper margin 16 and inner sole 11 may be of any suitable thickness sufficient to serve as a backing for the ribs 13 which are formed integrally thereon. The thinner the body portion i 5 is constructed the more resilient and pliable the sole will be.

It is proposed to extend the binding strip 14 which, as pointed out above, may be formed ²⁰integrally with the sole somewhat above the normal level of the body portion 10 so as to provide the sole with a recessed upper surface into which the vamp of the shoe may be fitted. This construction will give added strength to the shoe 25 and aid in preventing the sole from tearing loose from the vamp.

The construction of the heel is similar to that of the sole. The ribs 13, however, are made considerably deeper than in the sole so as to give ³⁰added height to the shoe, and a corresponding increase should be made in their thickness so that they will not be too unstable.

In Fig. 5 I have shown a modification of a shoe sole embodying my invention corresponding 35 to the cross-section of Fig. 3. In this modification the fins or ribs 13 are similar to those shown in Fig. 3 except that the ribs 18 lying in a central portion of a shoe are substantially deeper than those, 19, lying in the peripheral portion 40 of the shoe sole.

In the modification of my invention shown in Fig. 6 the ribs or fins 13 instead of running in straight lines the length of the sole are formed concentrically one within another. However, 45 they are still substantially of greater depth than width and the spaces between such ribs are relatively the same as described above for straight ribs.

In Fig. 7 is shown a modification of a heel 50 structure embodying this invention but Instead of the ribs being in substantially straight lines as shown in Fig. 2 they are formed concentrically to correspond with the modified sole shown in Fig. 6.

2,156,166

In the manufacture of soles and heels embodying this invention any material which is sufficiently pliable, resilient and wear resisting (such as rubber) may be used. It will be seen 5 that because of the yieldability of the Individual ribs, a resilient sole is provided which tends to conform to the configuration of the surface over which the wearer is walking.

In constructing footwear embodying the pres10 ent invention it is desirable that the ribs 13 be of the proper height or depth and thickness with regard to the substance out of which they are formed so that when a normal person for whom that particular footwear may be designed is sup15 ported on the sole the ribs 13 will not be excessively deformed.

However, the ribs should be sufficiently thin and flexible to yield under severe frictional thrusts exerted upon their ground engaging edges 20 such as will be exerted when the wearer jumps, stops or turns quickly, as in running upon a gymnasium floor. This yielding action of the ribs provides a cushion between the shoe sole and floor which allows an appreciable relative move25 ment between the body of the sole and the floor engaging edges of the ribs before the force of impact is checked by the frictional action of the ribs on the floor, thus increasing the resistance of the sole to slippage on the floor surface and 30 reducing the strain on the ankle and foot of the wearer.

As pointed out above, the ribs or flutes comprising the configuration on the outer sole of a shoe or other footwear embodying this invention are 35 relatively unstable. This is because they are substantially deeper than they are wide, and when a pressure is applied at an angle to the vertical axis of one of these flutes such flutes will not offer a great resistance to being deformed. The ._ ribs, however, do not completely collapse because, as pointed out above, the adjacent ribs are relatively close together and mutually interact to support one another under deformation.

Since the ribs or flutes are relatively thin and resilient they are somewhat extensible longi⁴⁵ tudinally and when a force is applied along one edge, such as when the person wearing the footwear makes a sudden stop, they will tend to extend themselves longitudinally and take up the sudden shock of stopping.

⁵⁰ The ability of a shoe constructed according to the present invention to cushion and partially absorb thrusts suddenly applied to its friction surface results in superior resistance to slipping and, since there is less sliding of the shoe on ⁵⁵ ground surfaces and less abrasion on the bottom surface of the shoe, the shoe has superior wearing qualities.

Although several embodiments of the invention have been herein shown and described, it ⁶⁰ will be understood that numerous modifications of the construction shown may be resorted to without departing from the spirit of this invention as defined in the appended claims.