NZ218968A - Shoe sole with a single curvilinear groove - Google Patents

Abstract

SHOE SOLES A shoe sole (l4) having at its bottom surface (l4a) a curvilinear flex groove (24) located at the narrowing region (22) forwardly of the wider region (20) of the shoe sole and extending from the medial side (24b) to the lateral side (24a) in a forwardly oriented arc having its forwardmost portion (24c) offset toward the medial side (24b), to underlie the inner space of the foot forwardly of the metatarsal heads and rearwardly of the phalangeal portions that serve for surface engagement.

Description

New Zealand Paient Spedficaiion for Paient Number £18968 Publication ''C' ■ P.O. Journal, No: ... / v 16 JAN 1987. ; :U NEW ZEALAND PATENTS ACT, 1953 No.: Date: COMPLETE SPECIFICATION : PARABOLA-FLEX SOLE Geo/?G£.

MALCOm tS^\BLISSETT, a citizen of U.S.A., of 1439 Sherwood, S.E., Grand Rapids, Michigan 49506, U.S.A., hereby declare the invention for which I / wj? pray that a patent may be granted to me/cca, and the method by which it is to be performed, to be particularly described in and by the following statement:- / 1 Q O (C 1 PARABOLA-FLEX SOLE *"• h tji $ \J BACKGROUND OF THE INVENTION This invention relates to footwear and particularly to a multidirectional toe-off shoe sole 5 structure.

Shoe soles have had a variety of features imparted to them over the years, often for the purpose of accommodating the natural action of the foot structure during locomotion, and/or improving foot action that is 10 defective in some respect. It is known that the human foot is a series of complex arrangements of bones, tendons, ligaments and muscles which produce a sequence of cooperative lateral and longitudinal movements during use. Although a great deal is presently known concerning these 15 foot movements, understanding thereof is yet incomplete. Moreover, because each person's foot varies considerably from those of others, efforts are constantly made to improve footwear for optimizing locomotion action. Yet, because shoes must be mass produced for practical reasons, 2 0 accommodating the variety of individual foot peculiarities is not totally possible. An object of this invention is to provide a special shoe structure which will aid in accommodating differing individual feet with a mass produced shoe.

SUMMARY OF THE INVENTION The present invention provides a shoe having a novel sole structure for increasing accommodation of the shoe to the peculiarities of individual varying foot action by allowing toe-off for proper weight transfer through the 30 gait cycle at any forward angle. The almost infinite number of directions of weight transfer from the shoe enables 1 proper toe-off for the peculiarities of the particular foot. It accommodates individual variations in bone alignment of the forefoot structure, and aids in extension of the phalanges at toe-off.

The novel shoe has a special curvilinear flex groove in the sole bottom, extending in a forward arc from the lateral side to the medial side, forwardly of the widest portion of the sole. This curvilinear groove underlies the "inner space" forwardly of the metatarsal heads and beneath 10 the rearward bone of the phalanges, i.e., behind the outer ends of the phalanges which engage the ground. The forwardmost apex of the groove is laterally offset toward the medial side of the sole. The radius of the flex groove addresses rotational shear in the forefoot encompassed 15 during resupination of the foot.

These and other objects, advantages and features of the invention will become apparent upon studying the following specification in conjunction with the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS 2 0 Fig. 1 is a side elevational view of a casual shoe employing the invention; Fig. 2 is a bottom view of the shoe in Fig. 1; Fig. 3 is a photo reproduction of an ink blot footprint plus a dash-line diagrammatic indication of the 2 5 shoe sole outline, a dash-line indication of the progressive line of contact of the foot to the ground, and a dash-line indication of the location of the flex groove forwardly of the metatarsal heads and behind the ground engaging portions of the phalanges; 1 Fig. 4 is a side elevational diagrammatic view of a foot showing the location of the inner space under which the flex groove lies; and Fig. 5 is a bottom view of a foot diagrammatically 5 showing the location of the flex groove beneath the inner space.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now specifically to the drawings, the invention is depicted in the form of a casual shoe 10 which 10 has an upper 12 secured around periphery 26 of sole member 14. This sole has a lower ground engaging surface 14a and an upper foot engaging surface 14b. An inner sole (not shown) or other conventional components may be employed as desired in conjunction with upper surface 14b.

This sole has a conventional heel portion 16 to accommodate the area underlying the heel of a human foot F contained in the shoe, and a narrow intermediate portion 18 which underlies the instep of the foot. The sole then widens out in conventional fashion toward the front of the 20 shoe to the widest portion 20 which underlies the metatarsal heads of the foot bone structure. The forwardmost portion 22 of the sole then narrows from this widest portion, and underlies the phalanges of the foot.

Beginning immediately forwardly of widest portion 25 20, so as to be forwardly of the metatarsal heads, is a special curvilinear groove 24. Specifically, it is directly beneath the "inner space" of the foot existing between the metatarsal heads and the forward, ground engaging portions of the phalanges. This curvilinear groove lies beneath the 30 rearward phalangeal bones. 1 The groove extends between the lateral side 24a of sole periphery 26 and the medial side 24b, in an arcuate path projecting forwardly of the sole from these two sides. The forwardraost apex portion 24c of the groove is laterally 5 offset from the center of the sole, toward the medial side, so that it is slightly toward the center of the sole from the great toe. This special groove 24 enables an almost infinite number of forward directions of flex and weight transfer upon toe-off during locomotion.

The cross sectional configuration of the groove is preferably smoothly curved, having at its upper deepest portion a concave generally semicircular curvature (Fig. 1), while merging gradually into two convex curved edge portions blending with the bottom surface 14a of the sole.

The curvilinear configuration of the groove from side to side adds volume to the groove to aid flexibility and enable further extension of the phalanges at toe-off. The ability of the curve of the flex groove to address an almost infinite number of forward directions of movement in 20 a casual shoe facilitates proper weight transfer through the entire gait cycle. The radius of the flex groove addresses rotational shear in the forefoot, encompassed during resupination of the foot. The depth of the groove may vary somewhat. Used in conjunction with a unitary type sole, the 2 5 flex groove may be considerably deeper for more surface area in the groove, which in turn results in increased flexibility.

In use of the shoe sole for walking, the usual basic pattern of foot to ground engagement is depicted by 30 the dash-line sequence 25 in Fig. 3. As is known, it begins at 25a at the heel, proceeds toward the metatarsal head 25b at the lateral side of the foot, then across the metatarsal heads to the head 25c behind the great toe on the medial side. During subsequent toe-off, the fleshy material 27 forwardly of the metatarsal heads and then the forward ends of the toes provide the engagement area, with the phalanges being extended for a springing action in the forward direction. Toe-off for the particular person's foot may be directly ahead as per the arrows in Fig. 5. Yet with different people and their own unique foot structure, toe-off direction can vary angularly from straight ahead. The novel sole readily accommodates any such individual locomotion toe-off direction characteristic because of the curvilinear groove which enables sole bending at that angular direction, for smooth comfortable action.

Certain additional advantages and slight modifications of the structure may be visualized by those in the art upon studying the foregoing teachings and the illustrated preferred embodiment. It is intended that the invention is to be limited only by the scope of the appended claims and the reasonably equivalent structures to those defined therein.

Claims (1)

1. A shoe sole comprising: an elongated sole having a bottom surface, a top surface and a periphery including a too with a forwardmost tip, and medial and lateral sides; said upper surface having a rear portion for engaging the heel of a foot, a narrow central portion to be beneath the instep of the foot, a wide portion to underlie and engage the metatarsal heads of the foot along the metatarsal-phalangeal joint line and a narrowing region forwardly of said wide portion for underlying the inner space of the foot occurring forwardly of the metatarsal heads and the metatarsal-phalangeal joint line, and engaging the forward ends of the phalanges of the foot; and said bottom surface of said narrowing region of said sole being provided with a single curvilinear groove, said groove being disposed forwardly of said wide portion, said curvilinear groove extending from said medial side, forwardly and then rearwardly in an arc to said lateral side, and being configurated and located to underlie the inner space of the foot forwardly of the metatarsal heads and the metatarsal-phalangeal joint line for allowing toe-off in a variety of forward directions; and said arc of said groove having an apex point thereon which is disposed closest to the tip of said toe, with said apex point disposed laterally closer to the medial side of said sole than the lateral side of said sole. - 2 - The shoe sole of claim 1 wherein said groove in cross sectional configuration has a concave curved upper portion blending into convex curved junctures with said bottom surface. - 3 - A shoe sole as claimed in claim 1 or 2 substantially as herein described and with particular reference to the accompanying drawings. < ; NEW ZEALAND By His/Xbeir authorised Agent PATENT OFFICE - 6 - A.J. PARK & SON 2 2 MAR 1990 Fer: —'