AU601005B2 - Shoe with spring-like sole member - Google Patents

Description

mo _on rl COMMONWEALTH OF AUAA fF PATENTS At(tT 1952

W~

Form COMPLETE SPECIFICATION (Or11GINAL) Class Application Number: Lodgf~d: Int. Class 'Com~plete Specification Lodged: Accepted: Published: Pr))ority t aL, i ~crrV Related Art Name of Applican~t; Address of Ainplcant; Actual Inventor: Address for Service: THE UNIVERSITY OF MICHIGAV4 Intellectual Property Office, Building, 550 East University, 1092, United States of America 225 West Engineering Ann Arbor, Michigan 841O9- DANIEL T. BARRY VDWD. WATERS SONS, 50 QUEEN STREET, MELBOURNE, AUSTRALIA, 3000.

Complete Specification for the Invention entitled: SHOE WITH SPRING-LIKE SOLE MrE'MBER T~e following statement Is a full description of this Invention, Including t69 best method of performing It known to, US seal-of Registered Patent Attorney Company and Signatures of its Officers as prescribed by its Articles of Association.

To: THE COMMISSIONER OF PATENTS.

WATERMARK PATENT, TRADEMARK ATTORNEYS SHOE WITH SPRING-LIKE SOLE MEMBER Background of the Invention This invention relates generally to footwear, and more particularly, to a shoe incorporated therein a leaf spring-like member which is formed of a fiberreinforced polymeric material for absorbing and releasing energy during each step.

A variety of approaches have been taken in the prior a't toward relieving the stresses which are imposed on a human foot during walking and running. One well known approach utilizes resilient, spring-like arrangements which absorb and release energy during each step of walking or running. The known arrangements store and release energy via resilient members which generally are arranged to operate in a direction which is generally S 15 orthogonal to the sole of the shoe so as to absorb and ,redistribute localized loads and forces.

U.S. Patent No. 4,492,046 describes a running shoe which has a springwire arrangement disposed in a longitudinal slot in the sole. The spring wire is arranged to urge the slot open apparently so that the heel of the wearer comes downward, the slot is closed, and as the weight of the runner shifts forward onto the metatarsal heads, or ba.ll, of the foot, the spring urges the upper section of the sole away from the lower section so as to assist in the weight shift. Such assistance is stated in the patent reference as launching the runner into a comfortable stride. Clearly, this known arrangement is complex, heavy, and probably dangerous in that the heel end of the bottom of the shoe may cause the runner to trip and fall.

A further known spring-action running shoe is described in U.S. Patent No. 4,534,124 which shows an athletic shoe coupled at its toe end to a leaf spring; the leaf spring being coupled at its rearward end to a further, lower solei As described in this la /i 1 actual ivento the assignee of the said actual inventor 4. The basic applications referred to in paragraph 2 of were this Declaration a the first applications made in a Convention country in respect of the invention the subject of the application.

I Patent Application UM: Daniel T. Barry reference, the running shoe proper is arranged parallel andat some' distance with respect to the lower sole, such that any weight being applied to the running shoe would result in a storage of energy in the leaf spring. Clearly, such a structure is heavy, bulky, complicated, and accident-prone.

It is, therefore, an object of this invention to provide a simple and economical show having associated therewith an arrangement for storing and releasing energy in a manner benefi- S cial to a runner.

1: t0 It is another object of this invention to provide an r arraigement which stores and releases energy in conformance with the natural foot movement of a runner.

It is a further object of this invention to provide a t running shoe having an arrangement where energy stored during each running step is released in a direction of travel of the runner.

S% It is also an object of this invention to provide a resil- «v t lent leaf spring-like member for incorporation in a shoe, the spring-like member having a lifetine of many flexures.

It is an additional object of this invention to provide a resilient spring-like member which cooperates with a shoe souas to have a flexure characteristic which is easily adaptable for a particular runner.

It is still another object of this invention to provide a resilient spring-like member for incorporation in a shoe so as to have a resilient characteristic which is easily adaptable'to complement the resilience characteristic of a running surface.

It is a still further object cf this invention to provide a resilient spring-like member which can easily be incpoporated in a running shoe.

7 Summary of the Invention The foregoing and other objects are achieved by this invention which provides a shoes having a sEso srntico\ y paner spring-li4k flexible resilient member arranged in the vicinity of the sole of the shoe. In accordance with the invention, the flexible resilient member has a predetermined flexure characteristic and is arranged to flex with the sole of the shoe, in the region of the ball of the foot of the human wearer, during each step. In this manner, the material, which may be a fiber-reinforced polymeric material, stores and releases energy in response to such flexure during each step.

In one embod:ment of the invention, the material which forms the flexible resilient member may be a carbon 15 fiber reinforced epoxy which is formed of a plurality of 1 *t layers. The configuration and thickness of each layer, Sas well as the number of such layers can be selected to i 4 form the predetermined flexure characteristic, In this manner, the flexible resilient member is adapted to the 20 weight and other characteristics of the wearer. In one L t.

embodiment, the various layers are bonded to one another.

Additionally, the entire flexible resilient member may be interposed between an outer sole of the shoe and an inner sole thereof which communicates with the foot of the wearer.

Each layer of fiber-reinforced polymeric material may have a flexure characteristic which is directional resulting from the orientation of the reinforcing fibers within the material, Typically, such material can withstand greater forces, such as bending forces, in the direction of the fiber orientation, than transverse thereto. In one embodiment of the invention, the various layers of fiber-reinforced material which form the flexible resilient member may each have a directional aspect to the flexure characteristic. Such layers may be arranged so that the directions of the fiber orientation are at respective angles to one another.

In this manner, the longitudinal and transverse flexure characteristics of the flexible resilient member can be 3tailored for a specific activity in which the human wearer is expected to engage. In a specific illustrative embodiment, the layers are arranged such that the fiber orientation of some of the layers is longitudinal with the shoe, while other such layers are at 450 to either side thereof. For most applications, the flexible resilient member will be stiffer in the longitudinal direction. As indicated, the stiffness of the flexible resilient member can be tailored to specific applications by varying the number of layers of fiber-reinforced material, as well as the angular orientations of the layers. Clearly the particular flexure characteristic to be incorporated in any given shoe should be tailored to the weight of the wearer, the running style of the wearer, the nature of the particular activity in which the wearer is expected to engage, and the characteristics of the surface on which such activity will take place.

A heavy runner will require a fairly stiff flexible resilient member, and therefore the flexible resilient member of a shoe tailored for such a runner would be formed with a greater number of layers of carbon fiber material, irrespective of shoe size. Additionally, sprinters will require stiffer flexible resilient members than marathon runners, since sprinting imposes greater forces and inertial loads on the foot of the runner that slower running, such as marathon running. Football player who generally are heavy athletes and are required to spring, would require relatively stiff resilient members in their shoes.

Tbh present invention is premised at least partially on the recognition by the inventor herein that j the achievement of effectual energy return for a runner, sufficient to improve the performance of the wearer in a given activity, requires shoes having incorporated therein resilient, spring-like members which are significantly stiffer, or more resistant to flexing, than conventional athletic shoes. This unatrstanding requires acceptance of a premise which is entirely contrary to the approach accepted by present dal shoe designers and 4 manufacturers.

The generally accepted view is that the speed and comfort of a runner is improved by using light and flexible footwear. This view is apparently deemed ithe present state of the art to be mandated by classical mechanics which assumes Chat reduction in the force required to flex the footwear during use of the shoe, and reduction in the mass of the footwear, will result ultimately in the reduction of total. energy required to be exerted by the user of the footwear, and thereby induce improvement in runner speed and endurance.

In accordance with a practical embodiment of the invention, the flexible resilient member is formed of plural layers of carbon fiber material which may be cast 15 in a solidifying material,, such as epoxy. In a running shoe, where only moderate lateral, or transverse, loads are encountered, it is desired to achieve a significant longitudinal stiffness, substantially along the axis of OF the foot, which stiffness operates to resist, in a springlike manner, flexure of the shoe in the vicinity of the metatarsal heads of the foot.

It is desired, in a running shoe embodiment of the Invention, to minimize transverse stiffness. Although 0 significant amounts of transverse stiffness can be avoided by aligning the fibers of the carbon layers longitudinally with respect to the foot of the user, the resulting absence of transverse support will permit the epoxy of the casting to fracture in a direction along the carbon fibers. Thus, in a practical embodiment a compromise is achieved by orienting the carbon fiber layers at predetermined angles with respect to one another, whereby they support each other. In a preferred embodiment, the carbon fiber layers at'e arranged at offsets correspondIng to rotation$ of approximately 100 from, the longitudinal axis.

In a highly advantageous embodiment, particularly with respect to shoes in the range of men's sizes 8 to 12, the resilient spring-like member is formed of four layers of carbon fiber material. The first layer is arranged so that its aligned carbon fibers are disposed _I C are disposed at a 100 counter clockwise orientation with respect to the longitudinal axis, and the second layer is arranged at a 100 clockwise orientation In order to achieve symmetry, and thereby avoid deformation during setting of the potting epoxy in the mold, the third and fourth layers are arranged at -100 and +100, respectively.

A shoe constucted using the flexible resilient member described hereinabove is thus tuned, in the sense of energy storage and return, within a range which would achieve the advantages of the present invention for a broad segment of the population. As previously indicated, the tuning of shoes for specific individuals can be achieved in a variety of ways, including using different numbers of carbon fiber layers in the resilient member.

For example, for sizes 4 to 8, two or three carbon fiber layers may be used.

The shoe of the present invention is not as flexible as conventional running shoes. Moreover, certain embodiments of the inventive shoe may be heavier than conventional shoes. Thus, the advantages of the present invention are achieved in a manner which seems contrar to the current thinking of those skilled in the art of shoe manufacture.

As previously noted, transverse stiffness may not be desirable in running shoes. Substantial transverse stiffness will exaggerate the wearer's tendency toward pronation, which is manifest as a rapid medial shift in the center of pressure 1 oertify that this and the preoeding pages are a true c i t..ap3 of pages of the spe liatiotn origlnaiJ Iodg(jd k) D 6- Lm*.

1-4- L- Patent Application UM: Daniel T. Barry immediately after the heel strikes the ground during running.

There are, however, activities such as tennis or basketball which require the participant to apply high transverse loads, particularly during rapid changes in direction. In accordance with the invention, shoes constructed for these types of activities are preferably provided with significant lateral stiffness, which can be achieved by increasing the angles of orientation of the aligned carbon fibers from approximately ±100 to ±900.

In some embodiments, the flexible resilient member will be to* tO generally planar and extend only throughout the foremost twori r thirds of the shoe. The heel portion of such a shoe could be provided with a cushioning material which will absorb and redistribute shock forces and loads. In other embodiments, however, the flexible resilient member extends throughout the length of the shoe and can serve the same function at the heel of the shoe as described hereinabove for flexure in the region of the metatarsal heads of the foot of the Wearer. In addition, the flexible resilient member need not be entirely planar, and instead may be curved in a manner which conforms to the sole of the shoe. For example, the flexible resilient member may be curved upward in the region of the front of the shoe.

In embodiments of the invention where the flexible resilient member does not extend for the entire length of the shoe, the rear portion of the shoe may be provided with a spacer formed of a resilient damping matetial. Such a spacer may be formed of a cushioing material, including a commercially available force distributing material marketed under the trade name Sorbothane.

When subjected to a shock-type load, this material functions somewhat as a liquid in that it distributes the load throughout itself. This has the effect of reducing the overall shock force 7 Patent Application UM: Daniel T. Barry experienced by any given point in the region of the heel of the foot of the wearer of the inventive shoe, In other embodiments of the invention, an inner sole is provided to prevent communication of the foot of the wearer directly with the flexible member. Such direct communication could result in bruising or other injury to the foot of the wearer, particu irly in the region of the metatarsal heads.

s "e Elimina on or reduction of this type of injury can result in significant improvement in the wearer's athletic performance. In 1 0 addition, certain embodiments of the invention may be provided with a metatarsal pad which is located on the inner sole in a region thereof which corresponds to a location immediately behind the metatarsal heads of the foot of the wearer. Such a metatarsal pad has the effect of lifting the foot slightly so as to ease the load on .he metatarsal heads. This, of course, can reduce fatigue-and improve performance. In addition to the foregoing, the inner sole may be provided with a metatarsal cushion located immediately beneath 'he metatarsal heads. Such a cushion would S serve to distribute more evenly the forces applied to the 2P metatarsal heads.

S

In acoordance with a further aspect of the invention, the flexible resilient member cooperates with the outer sole and the heel of the shoe to achieve a tuned response, Thus, the flexible resilient member functions as a spring, while the outer sole and heel operate as a damping medium. in addition, the inner sole can also function as a damping medium. The damping media may assist in reducing one or more oscillation modes of the shock Wave produced in a runner's leg by the impact at foot-strike and also may assist in tuning the system for the particular running characteristics of the wearer. Similarly, in embodiments of the invention 'where the flexible ,esilient member extends to the rear 8- T I Patent Application UM: Daniel T. Barry of yhe shoe so as to provide its advantageous effect in the heel regieon, cushioning material in this region can served to danpen oscillations as described hereinabove.

Brief Description of the Drawing Comprehension of the invention is facilitated by reading the following detailed description in conjunction with the annexed drawing, in which: So o FIG. 1 is a cross-sectional representation of a show constructed in accordance with the invention; 10 FIG. 2 is a cross-sectional representation of a further 4* embodiment of the invention wherein various structural components are removable; FIG. 3 and 4 are cross-sectional side, Ind plan top, views of an insole embodiment suitable for use with the invention; and FIG. 5 is a cross-sectional representation of a shoe constructed in accordance with the invention having a curved flexible resilient member and the iasole of FIG. 4.

Detailed Description FIG. 1 is a cross-sectional representation of a shoe constructed ai accordance with the invention. As shown, shoe has an upper portion 11 which may be constructed in a manner which is known in the at The shoe has an outer sole 12 which, in this embodiment. serves as the outermost bottom layer. A flexible resilient member 13 is arranged to communicate with outer sole 12 and exiends thrououghout the front portion of the shoe. In the rear portion ol the shoe however, a cushion spacer communicates With the outer sole and serves to dampen and distribute shock forces which ar. created when the heel portion of the shoe is urged ;nto (ommLunication with the ground (not 9 I II i i i i I t' Patent Application UM: Daniel T. Barry shown) during running. In addition, cushion spacer 15 serves to retain the flexible resilient member in place and avoid its shifting backward.

The flexible resilient member and the cushion spacer are covered, in this embodiment, byu an insole 16. In addition, this embodiment is provided with a soft cushion layer 17. The insole and the cushion layer serve to provide comfort to the wearer, while also protecting the foot of the wearer from direct communication with the flexible resilient member. In this specific embodiment, cushion layer 17 is provided with additional thickness in the vicinity of the heel portion of the shoe. This extra thickness provides an additional cushioning support which reduced transmission of peak forces during running to the heel of the wearer, 13 FIG. 2 is a croso-sectional representation of a shoe constructed in accordance with the invention so as to have removable components. This shoe has an upper portion 21 which may be of conventional construction. Additionally, the shoe is provided with an outer sole 22 and a flexible resilient membst 23. However, in this embodiment, an inner sole 24 is in direct communication With outer sole 22 and is interposed between the outer sole and the flexible resilient member. A cushion spacer is provided in the heel region of the shoe. However, unlike the embodiment of FIG. 1, the cushion spacer and the flexible resilient member in the embodiment of FIG. 2 are removable. when thus removed, shoe 20 can be used as a conventional shoe, with the foot of the Wearer communicating directly with insole 24.

Cushion spacer 25 is shown to couple with the flexible resilient member. Any of several known coupling arrangement s can be used to insure that the cushion spacer and the flexible resilient .meimber maintain their positions with respect to one another, In 10 Patent Application UMv: Daniel T. Barry this specific embodiment, a soft cushion insole 27 is provided on top of the flexible resilient member and the cushion spacer. Of course, cushion layer 27 is removable, thereby permitting access to the removable flexible resilient member and cushion spacer- FIGS. 3 and 4 are side and top plan views of an illustrative embodiment of a cushion insole 30 which is suitable for use with the shoe embodiments of FIGS. 1 and 2. Cushion insole, 30 can be formed in a conventional manner, However, in this embodiment there is provided a metatarsal pad 32 which is arranged or. the 1110 cushion Insole in a region thereof corresponding to a position t metatarsal cushion 33 which is located so as to communicate with the metatarsal heads of the foot of the wearer. 'In this embodiment, metatarsal cushion 33 is of the same thickness as the rest of tho otlahion insole.

5 Is a cross-.sectional representation of a shoe constructed in accordance with the invention and utilizing the insole described hereinabove With respect to FIGS, 3 and 4. This embodiment of the Invention has an outer sole 52, Immediately above Which is; arranged a flexible resilient: member 53. In this embodiment, the flexible resilient member exctends for only 4 portion of the length of the shoe:, there being provided a cushion spacer $5 which operates in the manner dqsoribod hereinabove with respect to the cushion spacers of FIGS. I and 2. The cushion spacer m~ay be formed of a viscous material which cushions the heol and also serves to damipen oscillations of the flexible resilient mnemiber, Alternately, the flexible resilient member can extend to the roar of shoe 50, thereby obviating the need for cushion spatcer 55, I;t stc an embodiment, Outer sole 520 and p.ossibly 4n inner sole 56 4ll cooperate with the foot of the, 11 Paten.. Application, UM: Daniel T. Barry wearer to dampen any~ ospillations i1r the flexible resilient member.

In this specific eMbodiment, flexible resilient member 53 has a predetermined curvature which can ad1d a Measure of comfort to the wearer.

This embodiment of the invention utilizes a removable cushion Insert 30, as described hereinabove, w~th respect to Figs, 3 and 4. As shown in FTG, 5, cushion insole 30 conforms to the curvature of the shoe, 1 0 Although the inventioni has been described In terms of specific embodiments and applications, persons skilled in the art cano in light of this teaching, gene~rate Aidditional embodiments without exceeding the scope or departing forM1 the spirit of the claimed invention, Accordingly It Is to be uid'rstood that the drawing and description in this disclose are Proflerec! to facilitate comprehension of the invention and should not be H construed~ to limi~t the, sqope thereof.

Claims (27)

1. A shoe of the type worn on the foot of a human being for performing a predeterminable activity on a surface, the shoe comprising: flexible outer sole means for communicating with the surface; and [flexible resilient means having a predetermined spring-like flexure characteristic and arranged in the interior of the shoe with respect to said flexible outer sole means, said flexible resilient means and said flexible outer sole means being arranged to flex together in response to flexure of the foot of the human being during a step of the predetorminable activity substantially in the region of the ball of the foot of the human being, whereby energy supplied by the human being is stored in said flexible resilient means in response to said flexure during each such step and released as said foot of the human being is lifted from the surface, said energy released from said flexible resilient means being returned to the human being in the form of a force having a magnitude characteristic applied to the human being over a time period, said magnitude and said time period being responsive to said predetermined flexure characteristic of said flexible resilient means.

2. A shoe as claimed in claim 1, wherein said flexible resilient means comprises a layer of carbon fiber reinforfed epoxy material.

3. A shoe as claimed in claim 2, wherein said carbon fiber reinforced material comprises a first layer of carbon fiber material cast within an epoxy material, said first layer of carbon fiber material having carbon fibers arranged in substantial alignment with each other, there being further provided at least a further layer of said carbon fiber material cast within said epoxy material, said carbon fibers of said further layer being arranged at a predetetm- 14 ined angle of orientation with respect to said first layer and with respect to a longitudinal axis of the shoe, to achieve said predetermined flexure characteristic,

4. A shoe as claimed in claim 1 wherein there is further provided inner sole means arranged in the interior of the shoe whereby said flexible resilient means is arranged intermediate of said flexible outer sole means and said inner sole means.

In a shoe for the foot of a human wearer, a& flexible resilient member disposed in the vicinity of the sole of the shoe and arranged to flex in response to flexure of the foot during performance of an Pctivity on a surface, said flexible resilient member being formed of at least a first layer of fiber reinforced material and adapted to store energy in response to flexure of the foot during performance of the activity by the human wearer, and release said energy to the human wearer upon relaxation of said flexure in the form of a force applied to the foot of the human wearer by said flexible resilient member.

6. A shoe as claimed in claim 5 wherein said fiber reinforced material is reinforced with carbon fiber.

7. A shoe as claimed in claim 6 wherein said flexible resilient member comprises a plurality of layers.

8. A shoe as claimed in claim 5 wherein said first layer of said fiber reinforced material is reinforced in a first direction to produce a predetermined flexure characteristic having a directional aspect.

9. A shoe as claimed in claim 8 wherein there is provided a second layer of said fiber reinforced material arranged to cooperate with said first layer and having a respective predetermined directional flexure characteristic, 9V t 15 said directional characteristics of said first and second layers being arranged at a predetermined angle with respect to each other, so as to produce a predeterminable mid- flexure characteristic having selectable, longitudinal and transverse aspects.

A shoe as claimed in claim 9 wherein said predeterminable mid-flexure characteristic is selected in response to a characteristic of a wearer.

11. A shoe as claimed in claim 10 wherein said predeterminable mid-flexure characteristic is selected in response to a type of activity in which said wearer is I i, expected to engage. V

12. A shoe as claimed in claim 10 wherein said flexible Sresilient member is curved upwards toward the front of the S* shoe.

13. A shoe as claimed i' claim 5 wherein there is further provided damping means coupled to said flexible resilient member for cooperating with said flexible resilient member.

14. A shoe as claimed in claim 5 wherein there is Sfurther provided inner sole means for separating the foot of a wearer of the shoe from said flexible resilient member.

A shoe as claimed in claim 5 wherein there is further provided heel cushion means for cushioning impact of the shoe during running.

16. A shoe as claimed in claim 5 wherein said flexible resilient member extends along the shoe for a predetermined fraction of the total length thereof.

17. A shoe as claimed in claim 16 wherein there is 4! 61^ f- 7^l 16 provided cushion spacer means arranged in the remaining portion of the total length of the shoe.

18. A shoe as claimed in claim 5 wherein there is 0vrther provided metatarsal support means arranged to relieve weight pressure on the metatarsal heads of the foot of the wearer.

19. A shoe as claimed in claim 18 wherein said metatarsal support means comprises a metatarsal pad arranged inside the shoe at a location therein corresponding to a position rearward of the metatarsal heads of the foot of the wearer.

A shoe as claimed in claim 18 wherein said metatarsal support means comprises a metatarsal cushion arranged inside the shoe at a location therein corresponding to a position beneath the metatarsal heads of the foot of the wearer.

21. A shoe for use on the foot of a human wearer, the shoe being of the type having a forward portion and a rearward portion, the shoe comprising: outer sole lgans arranged on the bottom of the shoe; and a spring-like member substantially in the form of a sheet of a fiber reinforced material, said spring-like member being arranged to be inward of said outer sole means and substantially parallel to said outer sole means so as to flex therewith and having a predeterminable flexure characteristic in the region of the metatarsal heads of the foot of the human wearer,

22. A shoe as claimed in claim 21 wherein said pring- like member is formed of a sheet of fiber reinforced material, said sheet having a plurality of layers of aligned fiber reinforcement, each such layer having a predetermined 17 orientation of fiber reinforcement, said layers being fixed at respective orientations of fiber reinforcement with respect to one another whereby said predeterminable flexure characteristic is achieved.

23. A shoe as claimed in claim 21 wherein said spring- like member is configured to extend the length of the shoe.

24. A shoe as claimed in claim 21 wherein said spring- like member is curved upward in the region of the front of the shoe.

A shoe as claimed in claim 21 wherein there is further provided inner soled means arranged substantially parallel to said spring-like member in the interior of the shoe.

26. A shoe as claimed in claim 21 wherein there is further provided cushioning means in the vicinity of the rearward portion of the shoe for absorbing shock loads imposed by the human wearer.

27. A shoe as claimed in claim 1, 5 or 21 substantially as hereindescribed with reference to the accompanying drawings. DATED this 19th day of December, 1989. THE UNIVERSITY OF MICHIGAN WATERMARK PATENT TRADEMARK ATTORNEYS, 290 BURWOOD ROAD, HAWTHORN, VICTORIA, AUSTRALIA. SKP:RCTS:BB(7.10)