Athletic Footwear

Abstract

A shoe for athletics comprising an upper, a sole portion, a heel portion and cleats secured to the sole and heel portions. The upper comprises an inner side made of an elastic material and an outer side made of a substantially inextensible material. Both inner and outer sides are secured to the sole and heel portions and provide a shoe which snugly fits the player. When the player is hit by a substantial impact force the inner side expands, absorbing energy from the force and allowing the foot to move laterally out of the shoe over the sole and heel portion to reduce injury.

Description

BACKGROUND OF THE INVENTION

A. Field of the Invention

This invention relates to protective footwear for use in athletics.

B. Prior Art

In competitive sports and particularly in football a common injury occurs to the knee of the player. The injury may be caused during play or practice in various ways. In one situation the injury occurs when the player is blocked or tackled and one or both of the player's legs becomes immobilized because the cleats of his football shoe become planted in the turf. The injury may be a major one with tearing of the knee ligaments or tendons. Instead of tearing, the injury may be in straining and stretching the ligaments and tendons or straining and stretching of the muscles. Operations are frequently required with long term recuperation.

In professional football, injuries have grown as the speed and size of the players and the resultant impact force have increased. In addition, with the use of artificial turf the problem has become worse since the traction of the tackler is greater than on natural turf. Further, the player's foot may be immobilized to a greater degree since there is somewhat more friction between the shoe turf than on natural turf. These injuries not only occur in professional football but also in college and high school games in which it has been estimated that 140,000 high school boys are getting knee and ankle injuries each year with about 50,000 being operated on for their knees.

It is understood that the knee with its associated ligaments and tendons is the weakest "link" since the hip can absorb torque. However, other injuries to the leg may occur if the force is great enough such as injury to the ankle or actual breaking of the leg. Further, other muscle strains may occur.

As a result of the severity of the injuries, much work has been done in an attempt to solve the problem. However, most solutions have been directed to improvements in the cleats or ripple sole of the shoe. Additional solutions have been suggested in bracing of the knee of the player. However, these prior attempts have left much to be desired and the above described injuries have not only continued but have increased.

In one example where injury occurs, the cleats of the right shoe immobilize the right leg and the player is hit somewhere along the right leg from the outside. With conventional football shoes the ankle may be laced and taped tightly so that there is no movement of the foot with respect to the shoe and the cleats. Accordingly, as seen from the side, the shoe, the foot and the thigh appear as a single rigid unbending unit. Injury is avoided when as a result of being hit, during a tackle for example, the cleats are torn free from the turf. In other instances, the force of impact is not sufficient to cause injury. However, if the cleats stay anchored and the force is sufficient the knee "pops."

SUMMARY OF THE INVENTION

A shoe for athletics comprising an upper, a sole portion and a heel portion. The upper comprises an inner side and an outer side. The inner side is made of an elastic material which is secured to the sole and heel portions. The inner and outer sides normally provide a snug fit for the foot of the wearer. However, upon application of a substantial impact force to the wearer the elastic material expands absorbing energy of the force and allowing the wearer's foot to move laterally out of the shoe over the sole and the heel portions. In this way, the likelihood that the wearer will be injured, particularly in his knee area, is substantially reduced.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a football shoe according to the invention;

FIG. 2 is a side view of the shoe of FIG. 1;

FIG. 3 is a rear view of the shoe of FIG. 1 taken along lines 3--3 of FIG. 2; and

FIGS. 4 and 5 are enlarged drawings of another form of the energy-absorbing material that may be used in the shoe of FIGS. 1--3.

Referring now to FIGS. 1-3 there is shown a football shoe of the "low-cut" type. It will be understood that the principles of the invention are not limited to football shoes but may be embodied in other athletic footwear such as those used in playing soccer, rugby, field hockey, etc.

Shoe 10, as illustrated, is for the right foot and comprises an upper 12 formed of an inner side portion 14 (closest to the other shoe) and an outer side portion 15. Outer side half 15 is made of leather having an inner liner of canvas as conventional and provides rigidity and support but little expansion. The inner side portion 14 is formed of an energy-absorbing fabric 11 later described in detail. A conventional reinforced collar 16 is provided having lacing eyelets 18 through which lacing 19 is threaded. Portions 14 and 15 are attached in any conventional manner such as by stitching to a sole portion 22a and heel portion 22b which may take the form of an integral one-piece bottom for shoe 10.

Fabric inner side 14 is stitched to outer side 15 along an interface through cap 20. This interface passes substantially through a center line of cap 20 which may be defined as a line longitudinal of shoe 10 extending from a sole 22 through the cap or center of the toe section extending to the lowermost part of collar 16. Fabric inner side 14 is then stitched around the inner side of collar 16. An upper edge 14a then extends around the ankle section and through the rear quarter ending at approximately the center of the back of shoe 10. It will be seen that upper edge 14a of inner side 14 extends higher around the ankle then upper edge 15a of outer side 15. Specifically as shown at its greatest extension 14c midway between collar 16 and seam 25, upper edge 14a extends about one inch further from heel 22b than edge 15a. From point 14c edge 14a and then edge 15a taper downwardly until at about one inch past seam 25 the minimum height of edge 15a is reached. In this manner edge 14a provides extra support for the foot by the extension of material 11 around the wearer's ankle.

A substantially vertical (transverse of the shoe) seam 25 is formed by stitching between inner and outer sides 14 and 15 from upper edges 14a and 15a terminating at a heel 226. Reinforcing heel strap 28 is secured to both inner side 14 and outer side 15 by stitching along side edges of the strap. A conventional insole 30 may be provided and cleats or spikes 32 are secured to bottom 22a - b in conventional manner. Insole 30 may be coated with teflon or other material for extra slip between the foot and shoe.

In order to provide additional support for the foot there are provided a pair of thin flat spring metal retaining members 34 and 35. Members 34 and 35 extend in a longitudinal direction of shoe 10 through the rear quarter of the shoe and embrace a substantial portion of the heel of the wearer. Members 34 and 35 are snugly received within pockets formed on the outside of side portions 14 and 15. Specifically an additional strip of expansible material 11 may be used to form each of pockets 34a and 35a.

In forming the pockets members 34 and 35 are placed within the respective pocket and then the strip forming the outer side of each pocket is sewn to sides 14 and 15. In this manner pockets 34a and 35a are centered with respect to the back of the shoe and run horizontally around the heel with the pockets being parallel to each other. In a typical example, member 34 may extend 2 inches in both longitudinal directions from rear seam 25. It will be understood that the construction of the left shoe (not shown) is the converse of right shoe 10. The inner side (closest to the other shoe) is made of energy-absorbing fabric 11 while the outer side portion (furthest from the other shoe) is made of leather. Thus the two fabric sides on the left and right shoes face each other.

The operation of right shoe 10 will be explained with respect to typical forces of impact which may be applied to a player's leg in the directions shown in FIG. 1. Thus a player may be hit or tackled on the right side which applies to the right leg a resultant force A or a resultant force B or a resultant force C in the illustrated directions. Similarly, a player may be hit on the left side which applies corresponding forces to the left side. It will be understood that the force of impact applied to the leg is transmitted to the player's foot. If the cleats are immobilized in the turf in the manner previously described, the foot then moves generally in the same direction as the applied force. Accordingly, the foot moves laterally or sideways, sliding on insole 30 and the fabric of inner side 14 expands to permit the foot to move partially out of the insole. In this manner, the fabric begins to take up the applied force. For a substantially large value impact force, the foot may move so far into inner side 14 so that about one half of the foot is over the edge of insole 30 and thus over the heel and sole portions 22a - b.

Force B is in a direction parallel to the front body plane and may cause all parts of the player's foot to move equally out into inner side 14 and over insole 30. However, force A comes more from a front direction and may cause a player to pivot around his instep with his toes moving out of the insole a greater distance of that of his heel. On the other hand, force C comes from the side and behind and may cause the heel of the foot to move further over insole 30 than that of the toes. Thus, it will be understood that depending upon the direction of the impact force, the toe and heel of the player must be free to move in response to that force. Thus, as shown in FIGS. 1 - 3, fabric 11 extends around the toe and the heel sections of shoe 10 sufficiently to allow freedom of lateral movement of the player's toe and heel respectively. It will be understood that inner side 14 may extend further towards the outer side of shoe 10 with seams 21 and 25 being accordingly moved. These seams must be placed to provide sufficient fabric 11 in the long direction so that the heel and the toe are each unrestrained. However, there must be a sufficient long dimension of the substantially rigid outer side 15 to provide support. Similarly, collar 16 may be made of fabric 11 if desired.

Another advantage of shoe 10 is that cleats 32 may disengage the turf as the foot moves into inner side 14 and over the edge of insole 30. At that time there is a change in the center of gravity of shoe 10, which may produce a tilting or large bending moment. In this matter those cleats 32 located on the outside of the foot may be pulled out of the turf. With the shoe no longer immobilized, the entire shoe may become free. At that time, the shoe can move and the force of impact is effectively removed from between the shoe and the foot.

It will also be understood that in an extreme situation where there is a high value impact force, the foot may move laterally to substantially the maximum expansion of material 11. The remainder of the impact force at that time may be effective to pull the foot out of the expanding shoe. In this manner, injury has been avoided.

Material 11 has energy-absorbing characteristics to provide the foregoing expansion to prevent injury on the one hand and to provide a normally snug-fitting football shoe. Only when the impact force is sufficient will material 11 expand to prevent the immobilization of the foot and to absorb energy of the impact force. It has been found that vertical stretch material, viz., the fabric stretches transversally of the shoe, a uniform expansion for the foot is provided. Specifically, the impact force is taken up by each part of the inner side of the foot over the toes, instep and heel. However, a stretch material may be used, having both vertical and horizontal stretch. The following are examples of fabrics 11 which may be used.

EXAMPLE A

Woven fabric weighing 30 oz./sq.yd. whose construction was Warp: 88 ends per inch with 2 ends of covered elastomeric yarn alternating with two ends of binder warp. The covered elastomer does not weave in the fabric and the binder warp weaves plain weave with the filling. The binder warp is 18/1 CC cotton yarn. The covered elastomer consists of a core of 0.02 inch cut thread with a first cover of 92/2 CC cotton yarn and a second cover of 100/2 CC cotton yarn for a total denier of 2193.

Filling: 98 picks per inch of 576 denier filament rayon

Take-up and crimp: A 2 inch length of fabric yielded 1.8 inch of covered elastomer and 5 inch of binder warp. 1.8 inch of covered elastomer yielded 1.4 inch of cut elastomer thread, 5.5 inch of second cover and 5.2 inch of first cover.

A 2 inch width of fabric yielded 2 inch of filling

EXAMPLE B

Double knit fabric weighing 30 oz./sq.yd. whose construction was face and fack fabrics: plain knit stitch with 15 wales/inch and 13 courses/inch. Face fabric consists of 3 ends of 25/1 CC cotton yarn knitting as one. Back fabric consists of one end of 345 denier filament rayon yarn. The covered elastomer is laid between the face and bach fabric 13 ends per inch with a binder yarn of 25/1 cotton yarn which knits in both face and back fabrics. The covered elastomer has a total denier of 9360 and consists of a cor of 0.03 inch wide cut thread, a first cover of 18/1 CC cotton yarn and a second cover of 4 ends of 20/1 CC cotton yarn. A two inch wide piece of fabric yields 11.3 inch each of the face, back and binder yarns and 2 inch of covered elastomer. 2 inch of covered elastomer yields 1.2 inch of cut-thread and 6 inch each of first and second cover.

Autographic tensil tests on the fabrics of Examples A and B show that these fabrics behave as nearly elastic bodies up to 100 percent extension. The woven fabric of Example A has a modulus of 50 pounds per inch of fabric and the knit fabric of Example B has a modulus of 60 pounds per inch of fabric. Since the actual force transmitted at the time of stopping or changing direction depends on a number of unknown factors, the effectiveness of the construction of shoe 10 is best evaluated in terms of the kinetic energy absorbed by shoe 10 at the time of stopping. In the following Table A is shown a proportion of the total available kinetic energy absorbed by shoe 10 for body weights of 210 and 250 pounds and for initial velocities of 10, 15 and 20 miles per hour. For comparison, these values are also listed for a normal shoe for which it is assumed that the leather has a modulus of 1,000 pounds per inch and that the leather can undergo a maximum extension of 1 percent. It is also assumed that fabric 11 can undergo an extension of 50 percent. ##SPC1##

In a rest position the lateral force exerted against the shoe by the player would depend on his angle of stance. In the following Table B is shown the extension of the shoe for 200 and 250 pound weight bodies and angles of stance of 5.degree. to 30.degree. .

TABLE B

In a rest position the lateral force exerted against the shoe will depend on the angle of stance. In the following table is shown the extension of the shoe for 200 and 250 pound bodies and angles of stance of 5.degree. to 30.degree..

Angle Normal Shoe 50 lb/in modulus 60 lb/in modulus 200 250 200 250 200 250 5.degree. 0.17% 0.22% 1.7% 2.2% 1.4% 1.8% 10.degree. 0.34% 0.43% 3.4% 4.3 % 2.9% 3.5% 15.degree. 0.5% 0.62% 5% 6.2% 4.2% 5.2% 20.degree. 0.64% 0.8% 6.4% 8% 5.4% 6.7% 25.degree. 0.77% 0.95% 7.7% 9.6% 6.4% 8.0% 30.degree. 0.87% 1.08% 8.7% 10.8% 7.2% 9%

EXAMPLE C

A still further example of material 11 is specifically illustrated in FIGS. 4 and 5 which comprises a layer of elastomeric fabric 11a and a top skin coat 11b. Coat 11b provides a leather-like appearance. The following is a detailed description of this material:

Fabric

A knit elastomeric fabric produces from an elastic yarn made from a prestressed rubber core of a specific size double wrapped with two protective contra-wound layers of cotton yarns. The helices of cotton wrapper yarns allows the rubber core to elongate under stress to a predetermined maximum. Upon removal of stress the rubber cotton structure retracts to essentially its original dimension.

Coating

The coated surface is made by cast coating techniques. That is, a top skin coat is adhered to the fabric by an adhesive coating both of which are solvent carried polyurethene elastomers. The skin coat may have various depths of graining depending upon the grade of release paper used.

Test

The modulus test is performed on a constant rate of traverse tester which conforms to Federal Test Method Standard No. 191, Method 5,100. Standard size test specimens are used and the modulus is calculated from the recorded stress and strain. Modulus is defined as the ratio of stress per unit area to the strain at a given percent (%) elongation.

The above material 11 shown in FIGS. 4 & 5 may have a modulus of 311 lbs./in..sup.2 at 100 percent elongation. It will be understood that the modulus may vary due to variations produced during manufacturing such as coating variability.

Claims

What is claimed is:

1. A shoe for athletics comprising

an upper, a sole portion and a heel portion,

said upper comprising an inner side portion and an outer side portion for normally providing a snug shoe fit for the foot of the wearer, said inner side portion being of an elastic material secured to said sole and heel portions which upon application of a substantial impact force to the wearer expands thereby absorbing energy of said force and allowing the wearer's foot to move laterally out of the shoe over said sole and heel portions thereby to reduce the likelihood of injury.

2. The shoe of claim 1 in which said elastic material is a fabric of vertical stretch whereby said impact force is taken up by each part of the inner side of the foot over the toe, instep and heel.

3. The shoe of claim 1 in which said outer side portion is made of substantially rigid material to provide support and said inner side portion extends around the toe and heel sections sufficiently to allow freedom of lateral movement of the wearer's toe and heel respectively.

4. The shoe of claim 3 in which said inner side portion extends substantially to the center of the toe section and the center of the heel section so that said toe and heel are unrestrained by said rigid material of said outer side portion.

5. The shoe of claim 1 in which there is provided spring retaining members secured to the rear quarter of the shoe for embracing a substantial portion of the heel of the wearer.

6. The shoe of claim 1 in which said inner side portion extends upwardly with respect to the outer side portion for providing extra support for the foot of the wearer.