EP0329392A2

EP0329392A2 - Tennis shoe having internally arranged navicular support stirrup

Info

Publication number: EP0329392A2
Application number: EP19890301405
Authority: EP
Inventors: Stephen M. Pasternak
Original assignee: Prince Manufacturing Inc
Current assignee: Prince Manufacturing Inc
Priority date: 1988-02-16
Filing date: 1989-02-15
Publication date: 1989-08-23
Also published as: JPH025903A

Abstract

A sports shoe has an upper with an inside liner stitched to an outside layer along predetermined paths to define a pocket. The pocket receives a pre-formed, anatomically shaped rigid stirrup member with sides lying on opposite sides of the shoe, a heel counter portion extending behind the foot, and free ends lying on opposite sides of the show forward of the foot-receiving opening. The stirrup is anchored to the sole on either side of the shoe and in the heel and includes means to attach the upper free ends of the sides in rigid tension-bearing engagement. The stirrup extends downwardly and rearwardly over the navicular bone of the foot and when the ends are attached becomes relatively rigid to provide navicular support.

Description

The invention relates to sports shoes, and in particular to tennis shoes.
Tennis and other active sports require quick reactions in stopping, turning, and lateral movements on the court. These movements can impart severe stresses to the bones, ligaments, and muscles of the foot. When certain stresses are imparted to the foot, the navicular bone of the foot tends to rotate about the longitudinal axis of the foot, collapsing the arch. Stresses are also imparted to joints associated with the navicular bone. The foot muscles and muscles in the leg work to compensate for this, which may cause fatigue and a tendency for ankle or knee injuries due to the strain of overcompensating muscles.
A number of proposals have been made in the past for supporting straps or other reinforcing or flexible members on sports shoes. However, prior reinforcing members are not were not designed to support the navicular bone and joints, and are thus largely ineffective or can even increase the stresses on the joints surrounding the navicular bone.
The one notable exception to this is the tennis shoe disclosed in my prior U.S. patent No. 4,670,998. This shoe has a rigid stirrup made of a high modulus, low elongation material which extends around the shoe upper in such a manner as to provide effective directional support to the navicular bone and associated joints. The rigid stirrup member includes portions on either side of the shoe, forward of the foot receiving opening, that extend downwardly and rearwardly to the sole, and a portion that extends around the back of the shoe behind the heel. The side portion on the medial side of the foot extends downwardly and rearwardly over the navicular bone of the foot, and when the shoe is laced the rigid stirrup member engages the navicular bone in a manner which inhibits rotation of the navicular bone and relieves stress in the associated joints.
The present invention is an improvement in tennis shoes of the type disclosed in my U.S. patent No. 4,670,998, which employ a rigid stirrup member for supporting the navicular bone. In particular, the present invention employs an improved rigid stirrup member which is incorporated in a new and better way into the structure of the shoe itself. In accordance with the invention, a pre-shaped rigid support strap is internally sandwiched between two layers of the shoe upper and is strategically anchored to the sole, along each of the sides and at the rear of the shoe. Because the piece is a pre-formed, shaped member; has an integral heel counter portion; and has an improved anatomically correct shape compared to the preferred embodiment of my '998 patent, in which the support piece is formed flat and then bent during lasting, the shoe has overall rigidity and support qualities comparable to the externally mounted embodiment shown in the preferred embodiment of my '998 patent while at the same time using a much thinner support member. This results in a lighter shoe, and improves the esthetic appearance of the shoe. The improvement in this invention also renders the shoe easy to manufacture. The selective deployment of the stirrup sidewalls effectively provides support to the navicular bone, moreover, without interference to foot movement.
A preferred embodiment of a shoe in accordance with the invention includes a sole, including an insole and an outsole affixed thereto, and an upper attached to the sole between the insole and the outsole. The upper includes an outer layer defining a foot receiving space, and an inside liner extending from the heel portion forward on either side at least to approximately the instep. Means for attaching the inside liner to the outside layer extend around the foot receiving opening spaced below the opening. Additional means for attaching the inside liner and outside layer are provided, forward of the foot receiving opening, that extend downwardly and rearwardly on each side of the shoe to the sole of the shoe, the attaching means thereby defining a pocket in the rear portion of the shoe upper. A pre-molded, shaped rigid stirrup member is disposed in the pocket, and preferably includes tabs that extend inwardly at approximately right angles to the sidewalls of the stirrup. The tabs anchor the support member to the sole on either side of the shoe and at the rear thereof, in the heel.
The internal stirrup piece may be molded of materials such as, but not limited to, nylon 6, 12, or graphite fiber or glass fiber-filled polymers. It includes a pair of upper ends lying forward of the foot receiving opening in the shoe. The upper ends project out of the pocket through slots formed in the upper and include holes for attaching laces. The upper ends may be free or may be stitched down. The rigid stirrup member also includes side portions that extend downwardly and rearwardly from the upper ends to the sole, and a heel portion that extends between the side portions around behind the foot in place of the normal counter of the shoe. The side portion on the medial side of the foot extends over the navicular bone, and the heel portion extends high enough behind the heel to envelope the os calcis bone of the foot. Preferably, the sidewalls of the stirrup are curved, or bowed, to follow the contour of the foot, and also so that the medial sidewall curves around and under the navicular bone.
The insole piece may be formed of an artificial soling material of the type sold under the trademarks Bontex or Texon, or fabric such as nylon, and the outsole may be a polyurethane which is formed, by injection molding, on the insole after the upper is attached to the insole. The shoe may be constructed using a cement lasting or slip lasting process, in which the lower edges of the upper, and the tabs of the stirrup member are cemented to the insole piece. Thereafter the outsole is formed by injection or compression molding, or a pre-formed outsole is cemented to the upper.
For a better understanding of the invention, reference is made to the following detailed description of a preferred embodiment, taken in conjunction with the drawings.

Figure 1 is a side view of a shoe showing the medial side of a shoe for the left foot;
Figure 2 is a side view of a shoe showing the lateral side of a shoe for the left foot;
Figures 3 and 4 are medial side and top views, respectively, of a rigid stirrup member used in the shoe of Figures 1-2;
Figures 5, 6, 7, and 8 are sectional views of the stirrup member taken through lines 5-5, 6-6, 7-7, and 8-8 of Figure 4, respectively;
Figure 9 is a sectional view of Figure 1, taken through lines 9-9; and
Figure 10 is a medial side schematic view of a shoe illustrating the anatomical relationship between the bone structure of a foot and the rigid stirrup member according to the invention.

A shoe 10 according to the invention includes an upper 12 and a sole 14 attached to the upper. The sole 14 may be formed of a dual density polyurethane, with an outer layer 16 of a relatively dense polyurethane, and an upper layer 18 of a less dense polyurethane, in accordance with known techniques. It may also be formed of an outsole and midsole of pre-molded materials in a standard cement process construction. As shown in Figure 9, the sole 14 also includes an insole piece 20, that may be made of an artificial soling material such as Texon or Bontex, or the like. Such insoles are well known and presently are used in some sports shoes as well as other types of shoes.
The upper 12 may be formed of leather, nylon, canvas, or any other suitable material. Referring particularly to Figure 9, the upper 12 includes an outside layer 22, that may be formed from several pieces of material in the shape of a shoe, and an inside liner 24 that extends from the heel section of the shoe 10 forward on either side of the shoe at least to a position forward of the foot receiving opening 26 (Fig. 1).
Referring to Figures 3-8, the shoe 10 also includes a pre-formed, shaped stirrup member 30 made of a high modulus, low elongation material, such as nylon 6, 12, or polymers containing carbon or glass fiber, so as to be rigid in tension e.g. relatively stiff plastic. The rigid stirrup member 30 is pre-molded in a shape to include a pair of anatomically correct substantially parallel side portions 32 and 34, that lie on opposite sides of the shoe so as to extend downwardly and rearwardly to the sole 14. It also includes a curved heel portion 36 that extends rearwardly behind the heel of the foot, between the side portions 32, 34. The heel portion 36 projects from the sole 14 upwardly to a height to cover the os calcis bone, as described further in connection with Figures 10.
A pair of side anchor tabs 40 extend from the lower end 38 of the rigid stirrup member 30 at each of the side portions 32 and 34. The tabs 40 project inwardly at approximately right angles to the sidewalls of the stirrup 30. A heel anchor tab 41 extends at an approximately right angle from the lower end of the heel portion of 36. If desired tab portions 40 and 41 can be one continuous piece.
As shown in Figure 9, the bottom edge of portion 42 of the inside liner, the bottom edge 44 of the outer, and tabs 40 are wrapped to extend inwardly over the bottom of the insole piece 20. The side tabs 40 (as well as the heel anchor tab 41) of the stirrup member 30 may extend slightly farther inwardly than the edge portion 42 of the inner liner 24, and the bottom edge portion 44 of the outer 22 may extend slightly farther than the tabs 40 and 41 of the stirrup member 30, so that each has a surface area in contact with the underside of the insole 20 and can be cemented thereto.
Referring to the sectional views of the stirrup shown in Figs. 5-8, preferably the sidewalls of the stirrup member 30 are anatomically curved or outwardly "bowed", to conform to the shape of the foot. Preferably also, the sidewalls are somewhat thicker in the middle. As an exemplary embodiment, the sidewalls have a thickness of about 2.5 mm at the midpoint M-M, tapering to a thickness of about 0.5 mm along the upper U-U edge. The tabs 40, 41, as well as the adjoining sidewalls, are about 1.5mm thick. The side tabs 40 and heel anchor tab 41 may extend inwardly a distance of 10 mm. Preferably, the thickness of the bowed sidewalls is sufficient so that the bowed sidewall portions are relatively inflexible. The upwardly extending ends 33, however, may be given a thickness less than the thicker portions of the sidewall, so as to be bendable sideways (without longitudinal elongativity) to facilitate inserting and removing the foot into and from the shoe. If desired, the outwardly facing surfaces of the upper ends may also be given ribs 35 and a decorative finish. When in the shoe, anchored to the sole, and laced, the stirrup piece forms a surprisingly rigid structure for (a) supporting the navicular bone in its proper position under stress; and (b) supporting the sub-talar joint, i.e., supporting the joints in a direction between the navicular bone and the os calcis bone.
As can be seen from Figures 3-6, the media and lateral 34 sides of the support member 30 are not mirror image; each side is shaped to conform anatomically to the shape of the respective side of the foot. Also, the end 33 on side 34 extends slightly forward of side 32 to accommodate the greater width on the lateral side of the shoe.
The stirrup member 30 is disposed between the outside layer 22 and the inside liner 24. The outside layer 22 and inside liner 24 are stitched along edges 46 and 48 lying forward of the foot receiving opening 26. The stitches extend downwardly and rearwardly to the sole, just forward of the stirrup member side portions 32, 34. The outside layer 22 and inside liner 24 are also stitched along edge 54, as shown by stitches 55 in Fig. 9. As shown in Fig. 9, an outer flap 60 may be provided to overlie the stitching along the edge 54. The stitches 55 extend around the foot receiving opening 26 and are spaced below the opening 26. The stitches along edges 54, 46, and 48 define a pocket for receiving the rigid stirrup member 30. The ends 33a, 33b of the stirrup 30 extend out from the pocket through slot openings 50, 52 formed in the upper. Lace holes 62 are formed in the upper free ends of the rigid stirrup sides 32, 34 for receiving laces in conjunction with lace holes 64 in the shoe. As shown, the stirrup member 30 replaces the normal (and thicker) heel counter.
Figure 10 is a view of the medial side of a left foot showing the bone structure and stirrup member. Shown in phantom are the calcaneous or os calcis bone 72, the talus or astragalus bone 74, the navicular or scaphoid bone 76, the internal cuniform bone 78, the first metatarsal bone 80, and two of the phalanges 82, 84. The tibia 86 is also shown, where it joins the talus 74.
The side portion 32 of the rigid stirrup member 30 on the media side of the foot projects downwardly and rearwardly over the navicular bone 76. When the shoe is tied, and the upper free ends of the side portions 32, 34 are thus laced together, the stirrup member is relatively inflexible. Because it extends around the navicular bone, and because the stirrup envelopes the navicular and os calcis bones, it provides support to the sub-talar joint and greatly inhibits movement of the navicular bone, as described more fully in my '998 patent, thereby providing improved support of the foot during sports activities. The anatomical shaping of the sidewalls of the present invention, as shown in Figures 4-7, is even better adapted, however, to envelope the foot and wrap around the navicular bone to provide support, since the sidewalls bow around the foot and navicular bone.
A shoe in accordance with the invention may be formed by a cement-lasted type of process. The upper 20, made with the outer 22 and inside liner 24, is pre-formed, and stitched along edges 46, 48, and 54 to form the pocket. Rigid stirrup member 30 is also pre-formed, e.g. by injection molding. The material used to make stirrup 30 is preferably a material with relatively good tensile strength, e.g. nylon 6, 12 or polymers containing carbon or glass fibers. An insole piece 20, cut in the shape of the bottom of a foot, is placed on a last (not shown), and the pre-formed upper 12 is positioned over the last, with the stirrup disposed in the pocket so that the free ends 32, 34 project out through the openings 50, 52. The bottom edge portions 42 and 44 are wrapped over the bottom edges of the insole piece 20, with the right angle tabs 40, 41 lying in between, in the manner shown in Figure 9, and the tabs 40, 41 and edges 42, 44 are cemented and heat set or otherwise adhered to the bottom of the insole material 20. Thereafter, the upper 12 and insole 20 assembly are placed on a mold, and an outer 14 is injected into the mold to adhere to the upper 12 and insole piece 20. This last step, for forming an outer in situ on a pre-formed upper, optionally with a dual density outsole, is itself a known process and need not be further described. As noted before, the shoe may also be made in a cement process in which the pre-formed upper is cemented to a pre-formed insole piece which, except for the presence of the novel internal support stirrup, is similar to known processes.
The foregoing represents a description of a preferred embodiment of the invention. Variations and modifications of the invention will be apparent to persons skilled in the art, without departing from the inventive concepts disclosed herein. All such variations and modifications are intended to be within the scope of the invention, as defined in the following claims.

Claims

1. A sports shoe having opposing medial and lateral sides comprising a sole and an upper, wherein the upper defines a foot-receiving opening and includes an outside layer and an inside liner that extends from the heel on the medial side of the shoe at least forward of the navicular bone of the foot, and on the lateral side of the shoe at least forward of the foot-receiving opening;
a support stirrup disposed between said outside layer and inside liner, said stirrup being formed in a shape having opposing side portions, one on either side of the shoe, a heel counter portion extending between the side portions behind the heel of the foot, upwardly from the sole to envelop the os calcis bone, and anchor means extending from the lower edge of each of the side portions and the heel counter portion for anchoring the stirrup to the sole; wherein the side portions include upper ends lying forward of the foot-receiving opening; wherein the side portion on the medial side of the shoe extends downwardly and rearwardly over the navicular bone of the foot; and wherein said support stirrup is formed of a thin, stiff plastic; and
means for releasably attaching, in rigid tension bearing engagement, the upper ends together.

2. A shoe as defined in claim 1, wherein the opposing side portions and heel counter have sidewalls which are outwardly bowed so as to be anatomically shaped relative to the foot.

3. A shoe as defined in claim 1, further comprising:
means for attaching the inside liner to the outside layer, said means extending in a path generally around the foot-receiving opening and spaced below the opening; and
means for attaching the inside liner to the outside layer spaced forward of a foot-receiving opening and extending downwardly and rearwardly on each side of the shoe, wherein on the medial side of the shoe the inside linear is attached to the outside layer forward of the navicular bone of the foot, the attaching means thereby forming a pocket in the rear portion of the upper, wherein said stirrup is disposed in said pocket.

4. A shoe as defined in claim 1, wherein the anchor means comprise one or more tabs that extend inwardly at approximately right angles to the side portions and heel portion.

5. A shoe as defined in claim 4, wherein the sole comprises an insole and an outsole, the insole having an upper surface and a bottom surface facing the outsole, and wherein the inside liner and outside layer included overlapping portions that are wrapped over edge portions of the insole bottom surface, such that the one or more tabs are disposed therebetween, and means for affixing the overlapping portions and tabs to the insole bottom surface thereby to be secured between the insole and outsole.

6. A shoe as defined in claim 2, wherein the sidewalls have a thickness so as to be relatively non-deformable, and wherein a pair of bendable, upwardly extending ends project from the sidewalls, to the upper ends.

7. A method of forming a shoe having opposing medial and lateral sides, comprising the steps of:

(a) forming an upper with an outer layer, defining a foot receiving opening, and an inside liner that extends from the heel on the medial side of the shoe at least forward of the navicular bone of the foot and on the lateral side of the shoe at least forward of the foot receiving opening;

(b) providing an insole in the shape of the bottom of a foot;

(c) providing a rigid stirrup shaped so as to have opposed side portions configured to lie on either side of the shoe, and a heel counter portion extending between the side portions and configured to extend behind the heel of a foot and upwardly from the shoe sole to envelop the os calcis bone, wherein the side portions include upper ends and lower ends, and wherein the side portion for the medial side of the shoe is configured to extend downwardly and rearwardly over the navicular bone of the foot, and shaped as to have anchor means extending from the lower edge of each of the side portions and the heel counter portion so as to anchor the stirrup to the sole, wherein the stirrup is formed of a thin, stiff plastic;

(d) positioning the stirrup between the outside layer and outside liner so that the upper ends lie forward of the foot receiving opening;

(e) wrapping lower end portions of the inside liner and outside layer, over edge portions of the insole, with the anchor means of the stirrup member therebetween, and affixing the end portions and anchor means to the insole; and

(f) affixing an outsole over the insole and the end portions of the inside liner, outside layer, and stirrup affixed thereto.

8. A method according to claim 7, comprising further the steps, prior to step d, of

(g) attaching the inside liner to the outer layer along a path extending generally around the foot receiving opening and spaced below the opening;

(h) attaching the inside liner to the outer layer on the medial side of the shoe along a path lying forward of the navicular bone, and extending downwardly and rearwardly;

(i) attaching the inside liner to the outside layer on the lateral side of the shoe along a path lying forward of the foot-receiving opening, steps g, h, and i thereby defining a pocket in the rear portion of the upper; and

(j) providing slot openings in the outside layer positioned to receive the upper ends of the stirrup, wherein, in positioning the stirrup member in the pocket, the ends of the stirrup extend out through the openings to overlie the outer layer.