WO1994021150A1

WO1994021150A1 - Shock absorbing and ventilating sole system

Info

Publication number: WO1994021150A1
Application number: PCT/US1994/003183
Authority: WO
Inventors: Michael L. Tanel; David Gerow; James Flaherty
Original assignee: Tanel Corporation
Priority date: 1993-03-24
Filing date: 1994-03-24
Publication date: 1994-09-29
Also published as: AU6368794A

Abstract

Improved athletic footwear including a shock absorption system (100) for the ball of the foot and heel regions which is adapted to provide an optimal force-deflection response while maintaining ease of manufacture, durability, and desirable shock absorption characteristics. The improved footwear also includes an outsole system (40). The shock absorption system (100) and outsole system (40) are adapted to center the foot over the center (30) of the shock absorber (100). Moreover, rather than resisting lateral forces, which are unavoidable in athletic footwear, the shock absorption system (100) allows the footwear to bank in response to lateral shear forces. The improved athletic footwear further includes a ventilation system (300) integrally formed with the shock absorption system (100), for exhausting stale air and fluids from inside the footwear. The ventilation system (300) is also adapted to provide fresh air into the interior of the footwear.

Description

SHOCK ABSORBING AND VENTILATING SOLE SYSTEM

TECHNICAL FIELD OF THE INVENTION

This invention relates to footwear. Specifically, the invention relates to fore midsole shock absorption system, rear midsole shock absorption system, ventilation system and outsole system for footwear. The shock absorber, ventilation and outsole systems of the present invention are useful in virtually all types of footwear, having particular utility when used in athletic shoes adapted for use in playing basketball, tennis, racquetball, squash, jogging, and various other athletic activities.

BACKGROUND ART

There has been substantial recent activity in the field of design and construction of athletic shoes. Athletic shoes are used in a wide variety of environments and on diverse surfaces. The typical athletic shoe has several well-known components: upper, sockliner, fiber board, midsole, and outsole. The shoe typically includes a support layer that is attached to the lower edges of the upper. Footwear is typically slip lasted (with a fabric support element) or board lasted (with a resilient support element) . Footwear also typically includes a sock liner. The midsole and outsole comprise a heel (or rear sole) region, and a fore sole region. The fore sole is typically centered around the portion of the shoe beneath the metatarsal joints, where the foot (and consequently the shoe) experiences the greatest degree of flexure. One of the principal problems facing shoe designers in general, and athletic shoe designers in particular, has been to cushion the extreme impact and shock of the foot striking the ground. The shock of ground contact during athletic activity is transmitted to the bones of the foot, and to the ankles, legs, knees, and back. These stresses can cause injuries. Although various methods of shock absorption are known, virtually all known shock absorption methods suffer from some disadvantage which limits their usefulness. The design of a shock absorption system for footwear necessarily involves certain trade-offs. One conflict noted by McMahon, in U.S. Patent No. 4,342,158, for Biomechanically Tuned Shoe Construction (August 3, 1982), is that in shoes relying on a volume of cushioning material for shock absorption — as do many shoes in commercial production today — an increase in the depth of the cushioning material results in an increase in its susceptibility to lateral shear. This condition is undesirable. Lateral shear allows the foot to shift with respect to the outsole of the shoe at impact, resulting in reduced shock absorption, instability, and loss of control.

Further, in known shock absorption systems for footwear, the energy expended to deform the heel material laterally is typically not returned to the wearer. Increasing the depth of the heel can result in a spongy feel of the shoe. As McMahon noted, these problems are accentuated in running shoes. Researchers have found that the stress on the foot depends to a large degree on the individual's speed, and is not highly dependent on the weight of the individual. The impact forces, and consequent shock absorption requirements, therefore, are greater during running than walking. Moreover, most amateur runners tend to land on their heels rather than on the balls of their feet. Athletic shoe designers have commented that this effect increases the importance of having an effective shock absorption system in the heel of the shoe. McMahon, for example, states that it is not widely recognized outside the area of athletic footwear that the shoe should absorb as little of the energy of impact with the ground surface as possible.

In addition, certain practical design considerations are critical. For example, the shoe must be light weight. This criteria is reflected in a steady reduction in the weight of running shoes over recent years, due primarily to the use of synthetic materials and advanced construction techniques.

It is also generally recognized in the field of athletic shoe construction that the shock absorption system must be durable and resilient. The typical shock absorption system must provide millions of cycles of shock absorption, without degradation of either the physical characteristics of the shoe or its energy response characteristics.

Further, the space available to perform this shock absorption function is typically constrained. The shock absorber must be compact and fit within the heel or fore sole region of the mid- or outsole, without adding unnecessarily to the height or weight of the shoe. The thickness of the sole is typically even more limited in the fore sole region than at the heel. Moreover, for court use, the shoe should have good lateral stability.

It is therefore an object of the present invention to provide a construction for footwear that will effectively absorb shock over the full range of applied forces encountered during activity.

Another object of the present invention is to provide a ventilation system which cooperates with shock absorption systems.

An additional object of the present invention is to provide a shock absorption system that will bank under the influence of shear forces being applied to the shoe, in order to impart to the foot a lateral component of force, to counteract the transverse force.

SUMMARY OF THE INVENTION

The invention is an improved shock absorption system for footwear, including rear and fore midsole shock absorbers, a ventilation system, and/or an outsole system.

The rear midsole shock absorber includes the following. A resilient midsole shock absorber system for footwear, comprising; first resilient means, having central and radial margin regions and a substantially concave surface, second resilient means, having central and radial margin regions and a substantially concave surface, the second resilient means disposed with the concave surface in opposition to the concave surface of the first resilient means so that the distance between the first and second resilient means is greater at the corresponding central regions than is the distance between the first and second resilient means at the corresponding radial margin regions; wherein the first and second resilient means are mechanically coupled at their respective radial margins; third resilient means having central and radial margin regions; the central region of the third resilient means further comprising a chord of the corresponding radial margins of the first and second resilient means, disposed substantially between the central regions of the first and second resilient means; the third resilient means being disposed between and mechanically coupled to the first and second resilient means at corresponding the radial margins of the first, second, and third resilient means; and the third resilient means further comprising a tensile means for maintaining the resistance of the shock absorber to compression through the full range of loading.

Preferably, the rear shock absorber of the present invention is disposed in the midsole of the shoe, in the heel area. In a preferred embodiment, the rear midsole shock absorber includes two primary shell spring elements and a secondary diaphragm spring element. The primary spring elements are preferably opposed shell springs. The secondary spring element is a unique diaphragm spring system. Whereas McMahon and others disclose opposed shell springs featuring a spiral spring or some other compressive material disposed between the two shell springs, the present invention further comprises a unique diaphragm, or at a minimum, a chord between the radial margins of the shell springs. This chord or diaphragm acts under tension to maintain the progressive resistance of the shock absorber system under increasing stress. Moreover, the shock absorber of the present invention includes a unique compressive region, located on the diaphragm or chord. This compressive region further reinforces the resistance of the shock absorber to increasing stress. In this configuration, the shock absorber of the present invention preferably has a spring constant in the range 40,000 to 132,000 lbf/ft. Moreover, as a result of the unique combination of elements of the present invention, the spring constant of the present invention progressively increases with increasing stress.

The inventive rear midsole shock absorber is also adapted to provide a unique response to lateral shear; a response that is not disclosed in any known shock absorber system. Certain prior shock absorbers make no, or at best inadequate, accommodation for lateral sheer, allowing the heel to roll relative to the ground surface. Others that do attempt to accommodate lateral sheer, such as McMahon, attempt to resist lateral sheer by stiffening the shock absorber to transverse force. This approach, however, extends the distance between the point of action of the shear force and the foot, increasing the moment of the shear force. The shock absorber of the present invention, in contrast, banks in response to lateral sheer, allowing the shock absorber to adapt to the heel in spite of the lateral shear force, and to return that lateral force to the foot.

The shock absorber of the present invention also centers the foot in the shoe. The center of the shock absorber is adapted to offer less resistance than are the radial margins. Accordingly, the foot will encounter less resistance in the center of the shock absorber. The inventors believe that this feature can aid in reducing injuries, and can allow the wearer to engage in athletic activity without aggravating or while accommodating certain injuries.

The shell springs are preferably formed of a resilient, high durometer plastic, having a modulus of elasticity in the range of 40,000 to 100,000 psi, good cyclic loading characteristics, and high fatigue resistance. The spring assembly itself constitutes the midsole portion of the heel of the shoe and, in several embodiments, the radial margins of the spring assembly are visible along the outer circumference of the midsole of the heel.

The shell spring assembly is generally circular, although in certain embodiments it is elongated in an elliptical direction with its longitudinal axis aligned substantially parallel to the longitudinal axis of the shoe. The axes of rotation of the primary shell springs and the secondary diaphragm spring element are substantially vertical with respect to the shoe.

The invention further includes an improved fore midsole shock absorption system. Specifically, the fore midsole shock absorber includes the following. A resilient base means further comprising first and second surfaces, and central and radial margin regions; at least one annular projection disposed from the second surface of the base means, having proximal and distal ends; the projection subtending substantially the central region of the second surface of the base means; whereby the annular projection and the base means comprise a shell spring; whereby the shell spring absorbs energy and shock applied to the fore sole and whereby the shock absorber is adapted progressively to resist compression.

Preferably, the fore midsole shock absorber of the present invention is disposed in the midsole of the shoe, in the foresole area. In a preferred embodiment, the shock absorber includes a series of concentric, nested, shell spring elements. As a result of the unique combination of elements, the spring constant increases progressively with increasing stress.

The fore midsole shock absorber of the present invention also centers the foot in the shoe. The center of the shock absorber is in some embodiments adapted to offer less resistance to stress than are the radial margins. The present inventors believe that this feature aids in reducing injuries, and can allow the wearer to engage in athletic activity without aggravating or while accommodating certain injuries.

The construction of the fore and rear midsole shock absorbers also includes various arrangements for mounting the shock absorbers to the shoe. The shock absorbers can be formed integrally with the midsole of the shoe or can be formed separately. In one embodiment of the present invention, the shock absorber can be replaceable, allowing the wearer to adapt the shoe to their personal characteristics or the characteristics of the use being made of the shoe. This can be accomplished through the use of a mounting plate or assembly that can be secured to the sole. It can take various forms, such as a snap-on joint, a series of cooperating tabs and slots, a threaded mounting aperture, etc. When the heel construction is secured to the sole of the shoe by a screw arrangement, the heel can include mechanical means such as a tab and set screw for securing the heel against rotation once it is firmly secured to the shoe.

The invention further includes an improved ventilation system for footwear. Specifically, the ventilation system for footwear includes the following. A resilient compression means disposed in the midsole in substantially parallel relation to the plane of the midsole; the compression means further comprising, first and second resilient means, having an aperture formed therein, wherein the first and second resilient means are mechanically coupled comprising a substantially air-tight seal; valve means cooperating with the aperture for controlling the flow of fluid through the ventilation system; wherein fluid is exhausted from the compression means when the midsole is placed in compression by the foot and wherein fluid is admitted into the compression means when the foot pressure is released.

Preferably, the ventilation system of the present invention is formed as part of the rear and/or fore sole shock absorber. The invention can also include air passages to allow multiple ventilators to communicate with one another and/or air bladders to provide additional support to certain portions of the shoe. Since the ventilation system effectively exhausts fluids from footwear, it is useful in any type of shoe, including athletic footwear and boating footwear.

The invention further includes an improved outsole system for footwear. Specifically, the outsole system is adapted to absorb shock and includes the following. A resilient outsole surface further comprising first and second surfaces and central and lateral margin regions; at least one annular projection disposed from the second surface of the outsole surface, the annular projection further comprising proximal and distal ends, the proximal ends corresponding the point where the annular projection is disposed from the outsole surface; the annular projection subtending substantially a portion of the central region of the second surface of the sole; whereby the annular projection and the outsole comprise a shell spring for absorbing energy and shock.

Preferably, the outsole system of the present invention is disposed in the fore and rear sole regions. In a preferred embodiment, the outsole system forms concentric, nested, shell springs to absorb shock. The center of the outsole shock absorber is adapted to offer less resistance to stress than are the radial margins, centering the foot in the shoe. The present inventors believe that this feature can aid in reducing injuries, and can allow the wearer to engage in athletic activity without aggravating or while accommodating certain injuries. The outsole system is generally circular, although in certain embodiments it is elongated to an elliptical direction with its longitudinal axis aligned substantially parallel to the longitudinal axis of the shoe.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 is a partial section, oblique cut-away view of an embodiment of the present invention, including fore and rear midsole sole shock absorbers, ventilation system, and outsole system.

Fig. 2 is a transverse, cross-sectional view of the heel portion of a preferred embodiment of the rear midsole shock absorber of the present invention, taken along line A-A of Fig. 1, including a ventilation system.

Fig. 3. is a transverse, cross-sectional view of the heel portion of an embodiment of the rear midsole shock absorber of the present invention, taken along line A-A of Fig. I, including a ventilation system. Fig. 4 is a transverse, cross-sectional view of another embodiment of a rear midsole shock absorber of the present invention, without compressive elements on the diaphragm.

Fig. 5 is a transverse, cross-sectional view of another embodiment of the rear sole shock absorber of the present invention.

Fig. 6 is an oblique, cross-sectional view of an embodiment of the rear sole shock absorber of the present invention, taken along Section A-A of Fig. 1.

Fig. 7 is a transverse, cross-sectional view of an embodiment of the rear sole shock absorber of Figs. 6 and 3, including the ventilation system and outsole system.

Fig. 8 is a transverse, cross-sectional view of a present, preferred embodiment of the rear sole shock absorber of Fig. 2, including ventilation and outsole systems, of the present invention.

Fig. 9a is a top view of the upper shell spring of the rear sole shock absorber of Figs. 6 and 7.

Figs. 9b, 9c, and 9d are transverse, cross-sectional views of the upper resilient shell spring of the rear sole shock absorber of Figs. 6 and 7, showing cross-sections of the upper shell spring at sections A, B, and C, respectively, of Fig. 9a.

Figs. 10 is a top view of an embodiment of the diaphragm of the rear sole shock absorber of Figs. 3, 6 and 7, of the present invention.

Fig. 11a is a schematic diagram of a present preferred embodiment of the rear midsole shock absorber of the present invention, depicting the banking function of the shock absorber.

Fig. lib is a simplified transverse cross-sectional diagram of an embodiment of the rear midsole shock absorber of the present invention, depicting the banking function of the shock absorber, as shown in Fig. 11a.

Fig. 12 is a force-deflection graph, depicting the response of opposed shell springs, without reinforcement. Fig. 13 is a force-deflection graph, depicting the response of a preferred embodiment of the rear midsole shock absorption system of the present invention.

Fig. 14 is a force-deflection graph, depicting the response of a preferred embodiment of the fore midsole shock absorption system of the present invention.

Fig. 15 is a force-deflection graph, depicting the response of a preferred embodiment of the outsole shock absorption system of the present invention.

Fig. 16 is a graph comparing the force-deflection response of a preferred embodiment of the shock absorption system of the present invention relative to McMahon^,s shock absorption system. Fig. 17 is a partial, cut-away, side view of the midsole of an athletic shoe of the present invention showing the relative positions of the rear and fore midsole shock absorption systems of the present invention.

Fig. 18 is a longitudinal, horizontal, section view of the midsole of an athletic shoe of the present invention, showing the relative positions of elliptical embodiments of the rear and fore midsole shock absorption systems of the present invention.

Fig. 19 is a longitudinal, horizontal, section view of the midsole of an athletic shoe of the present invention, showing the relative positions of elliptical embodiments of the rear and fore midsole shock absorption systems of the present invention.

Fig. 20 is a plan view of the underside of an embodiment of the fore midsole shock absorber of the present invention, showing the flex grooves formed therein.

Fig. 21 is a transverse, cross-sectional view of the fore sole shock absorption and outsole systems of the present invention.

Fig. 22 is a transverse, cross-sectional view of a preferred embodiment of the fore sole shock absorber of the present invention.

Fig. 23 is a transverse, cross-sectional view of another embodiment of the fore sole shock absorber of the present invention. Fig. 24 is a transverse, cross-sectional view of other embodiments of a fore sole shock absorber and outsole system of the present invention.

Fig. 25 is a transverse, cross-sectional view of another embodiment of the outsole system of the present invention.

Fig. 26 is an underside, plan view of the outsole of an athletic shoe of the present invention, showing a present preferred outsole configuration.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS Reference will now be made in detail to a preferred embodiment of the present invention, including a rear midsole and fore midsole shock absorption systems, ventilation system, and outsole system, examples of which are illustrated in the accompanying drawings. An embodiment of the present invention is shown in Fig. 1 as 10. Specifically, Fig. 1 illustrates an athletic shoe of the present invention having a rear midsole shock absorption system 100, a fore midsole shock absorption system 20, ventilation system 30, and outsole system 40. Each system is discussed in greater detail below.

I. The Rear Midsole Shock Absorber

Figs. 2-8 illustrate various embodiments of the rear midsole shock absorber system 100. A transverse cross- sectional view, taken along section line A-A of Fig. 1, of a present preferred embodiment of the rear midsole shock absorber of the present invention is shown in Figs. 2 and 8 as 100. Other embodiments are shown in Figs. 3 through 7. An oblique, cross-sectional view of one embodiment of the rear sole shock absorber invention is shown in Fig. 6 as 100.

As depicted in Figures 2 through 8, shock absorber 100 comprises three principal elements: first resilient means 110, second resilient means 120, and third resilient means 130. As embodied herein, and shown in Figs. 2 and 8, first and second resilient means 110 and 120 further comprise shell springs respectively having central regions 112, 122; radial margin regions 114, 124; concave surfaces 115, 125; flanges 116, 126, respectively. In a preferred embodiment of the present invention, first and second shell springs 110 and 120 are disposed with their radial margins abutting one another and their concave surfaces 115 and 125 facing one another, so that they are separated at their respective central regions 112 and 122 by a distance dependent on their respective degrees of concavity, forming a volume between them.

Referring now to Figures 2 through 8, third resilient means 130 comprises at least a chord, spanning the radial margins of shell springs 110 and 120. In a preferred embodiment of the present invention, as shown in Figs. 2 and 8, third resilient means 130 further comprises tensile means 140 and compressive means 150, aperture 131, central region 132, radial margin region 134, edge 136, first surface 135, and second surface 137. As shown in Figs. 3, 5, 6, and 7, in certain embodiments of diaphragm 130 further comprises flange 138, and ring 139.

In a preferred embodiment of the present invention, shell springs 110 and 120 are reinforced by diaphragm 130. In mounted relation, the central and radial margin regions of first and second shell springs 110 and 120 and diaphragm 130 are each disposed in corresponding relation to one another, with diaphragm 130 sandwiched between the opposing concave surfaces 115 and 125 of first and second shell springs 110 and 120.

Referring now to Figures 9a through 9d, the shock absorption system 100 further comprises coupling means 160 for mechanically coupling first shell spring 110, second shell spring 120, and diaphragm 130. As embodied herein, coupling means 160 comprises a series of alternating, cooperating pins 162 and apertures 166 formed on the concave sides of first and second spring shells 110 and 120 at their respective radial margins 114 and 124. As shown in Fig. 10, coupling means 160 further comprises corresponding apertures 164 formed in diaphragm 130. Apertures 164 cooperate with pins 162 of shell springs 110 and 120 to mechanically couple shell springs 110 and 120, and diaphragm 130.

First and second shell springs 110 and 120 preferably are disposed with their concave surfaces in opposing relation, as shown in Figs. 2 through 8 with disc 130 sandwiched between them, so that the radial margins of all three elements, 114, 124, and 134 are abutting. In a preferred embodiment of the present invention, apertures 166 are smaller in diameter than the outer circumference of pins 162. Further, pins 162 preferably have a shoulder 163 formed in their distal ends, as shown in Figs. 2 and 8. In a preferred embodiment of the present invention, as shown in Fig. 8, the distal ends of pins 162 extend into but not through cooperating apertures 166 so that shoulders 163 of pins 162 abut the margins of apertures 166, when shell springs 110 and 120 are in mechanically coupled relation. Preferably, pins 162 are ultrasonically welded at the distal ends to the margins of apertures 166.

It will be apparent to those skilled in the art that various modifications and variations can be made to the coupling means 160 of the present invention without departing from the scope or spirit of the invention. As an example, coupling can be achieved by use of various known fasteners, including glue, screw fasteners, snap-together parts, interference fit, and various "welding" technologies as can be appropriate to the materials involved. Any other appropriate coupling means that is able to mechanically fix the radial margins of the shell springs and diaphragm can also be used. Further, apertures 166 could be dimensioned larger in diameter than the outer circumference of pins 162, so that pins 162 extend through apertures 166. The distal end of pins 162, extending out the exterior surface of opposing shell spring 110 or 120, could then be heat fused, glued, or otherwise fastened in a known manner. Thus, it is intended that the present invention cover the modifications and variations of the invention, provided they come within the scope of the appended claims and their equivalents.

Referring now to Figs. 2, 3, and 6 through 8, diaphragm member 130 further comprises tensile means 140 and compressive means 150. In a preferred embodiment of the present invention, the combination of tensile means 140 and compressive means 150 reinforces diaphragm means 130 and maintains the ability progressively to resist increasing force across the full range of loading of shock absorber 100.

As described thus far, coupling means 160 defines the radial extent of tensile means 140 portion of diaphragm 130. In a preferred embodiment, shock absorber 100 further comprises a tongue and groove system 392, 394,and 396, shown in Figs. 2 and 8, which defines the radial extent of tensile means 140. As shown in Figs. 2 and 8, shell spring 110 and 120 preferably have tongues 392 and 394, respectively, formed thereon at their respective radial margins on concave sides 115 and 125 of shell springs 110 and 120. Diaphragm 130 preferably has a groove 396 formed in both first 135 and second 137 surfaces thereof to cooperate and mate with tongues 392 and 394. Tongues 392 and 394 and groove 396 preferably are disposed radially proximal to coupling means 160 at the radial margin 114, 124, and 134 of shell springs 110, 120, and diaphragm 130, respectively. In a preferred embodiment of the present invention, as shown in Figs. 2 and 8, tongues 392 and 394 and groove 396 define the radial extent of tensile means 140. In another embodiment of the present invention ring 139 is formed at the radial edges of diaphragm 130, as shown in Figs. 3 through 7, defining the radial extent of tensile means 140.

In a preferred embodiment of the present invention, and as shown in Figs. 2, 3, and 6-8, compressive means 150 of diaphragm 130 further comprises a plurality of discrete annular compressive elements projecting distally out from first and second surfaces 135 and 137, respectively, of diaphragm 130 in a direction substantially normal to the plane of diaphragm 130 and substantially parallel to the axis of rotation of diaphragm 130. Compressive means 150 cooperate with corresponding regions of concave surfaces 115 and 125 of first and second shell springs 110 and 120, respectively, to reinforce the force-deflection characteristics of shock absorber 100, and to center the wearer's foot in shock absorber 100. Compressive means 150 extend distally away from surfaces 135 and 137 of diaphragm 130 in a direction substantially normal to the radial plane of diaphragm 130. As embodied herein, and shown in Fig. 8, multiple compressive means 150 are disposed from first and second surfaces 135 and 137 of diaphragm 130. Preferably, each compressive means 150 terminates at a distance less than the distance to the cooperating regions of concave surfaces 115 and 125 respectively of shell springs 110 and 120. Compressive means 150 are preferably disposed in spaced apart relation so that they do not interfere with each other, when shock absorber 100 is under compression.

In a preferred embodiment of the present invention, as shock absorption system 100 is loaded, shells 110 and 120 are compressed and are progressively deformed from their unloaded, concave shapes. As shell springs 110 and 120 are loaded, they deform, forcing their radial margins outward in a radial direction. Tensile means 140 resists radial movement of the radial margins of shell springs 110 and 120. Compressive means 150 come progressively into contact with first and second shell springs 110 and 120, further reinforcing the resistance of shock absorber 100 to compression.

It will be apparent to those skilled in the art that various modifications and variations can be made to the tensile means 140 and compressive means 150 of the present invention without departing from the scope or spirit of the invention. For example, compressive means 150 and/or shell springs 110 and 120 can be modified to control the manner in which compressive means 150 are flexed or loaded. Proximal and distal compressive elements 156 and 152 could be disposed to physically interfere with each other or to flex in a predetermined direction under compression, if desired, in order to reinforce the ability of compressive means 150 to resist compression. As a further example, compressive means 150 could further comprise distal compressive element 152, one or more medial compressive element(s) 154, and proximal compressive element 156. As shown in Figs. 3, 6, and 7, the distance between the terminal ends of distal compressive element 152 nd concave surfaces 115 and 125 of first and second shell springs 110 and 120, respectively, is less than the distance between the terminal ends of medial compressive elements 154 and concave surfaces 115 and 125. In turn, as shown in Figs. 3, 6, and 7, the distance between the terminal ends of proximal compressive element 156 and cooperating portions of concave surfaces 115 and 125 is larger than that between the concave surfaces and the terminal ends of each of the medial compressive elements 154. Under progressive loading of the shock absorber 100, distal compressive element 152 contacts concave surfaces 115 and 125 first. As shock absorber 100 is further loaded, medial compressive elements 154 progressive come into contact with concave surfaces 115 and 125. As loading continues, terminal ends of proximal compressive element 156 contacts concave surfaces 115 and 125.

As another example, tensile means 140 can be modified to further reinforce shell springs 110 and 120. For example, as shown in Figs. 3-7, edge 136 of diaphragm 130 can be modified to form a circumferential ring 139 at the radial extent of diaphragm 130. In addition to the resistance of tension element 140, ring 139 provides additional tensile resistance to outward radial movement of the radial margins 114 and 124 of shell springs 110 and 120. In other embodiments, shell springs 110 and 120 could be disposed so that their concave surfaces are parallel, namely, facing in the same direction. Moreover, one or more shell springs could cooperate with the outsole system of the present invention to provide shock absorption. Additional embodiments could include only a single shell spring, either alone or in combination with the outsole. In addition, as shown in Figs. 2, 3, 5, 6 and 8, shell springs 110 and 120 and diaphragm 130 can each also comprise central apertures 111, 121, and 131 respectively. Apertures 111, 121, and 131 work cooperatively with the ventilation system described below. Further, diaphragm 130 can take the form of a simple diaphragm as illustrated in Fig. 4, or an apertured diaphragm as shown in Fig. 5. In addition, compressive elements 150 can have slits or ribs formed therein to prevent them from forming a suction between diaphragm 130 and shell springs 110 and 120. Thus, it is intended that the present invention cover the modifications and variations of the invention, provided they come within the scope of the appended claims and their equivalents.

The construction of the present invention provides two additional unique benefits: it centers the foot in the shock absorber; and accommodates lateral shear by banking to provide greater resistance on the side of the shoe to which the lateral force is applied. The centering function is accomplished by offering less resistance to compression at the center of shock absorber 100 than at the radial margin. As shown in Figs. 2 through 8, no compression means are disposed at the central region of disc 130. At any point during loading the radial margins offer greater resistance to compressive force than does the central region of shock absorber 100, resulting in a centering force being applied to the foot.

The banking function of the shock absorber 100 is also unique. A present preferred embodiment of the present invention is depicted in a simplified schematic diagram in Fig. 11a as a set of idealized mechanical linkages. As shown in Fig. lib, as a shear force is applied in a transverse direction relative to the longitudinal axis of the shoe, shock absorption system 100 banks to oppose that force.

As embodied herein, and illustrated in an idealized schematic diagram in Fig. 11a, the side of the shock absorber to which the shear force is applied collapses more than the opposite lateral side in response to the shear force, forming a banked surface to support the foot. Specifically, as depicted in Fig. 11a: first shell spring 110 is shown as stylized three bar linkage: A-B-C-D; second shell spring 120 is shown as stylized three bar linkage: A-F-E-D. Shock absorber 100 is shown in Fig. 11a in the unloaded position as A-B-C-D-E-F-Λ; and in a loaded position as A'-B'-C'-D'-E'-F' . The bank angle is shown as θ, that is, the angle formed by the upper surface B'-C of shock absorption system 100 in the shear-loaded position, relative to the normal, unloaded position of the upper surface B-C of shock absorber 100. Angle β is defined as the angle formed by the idealized surface C-D of upper shell 110 relative to the vertical; angle Φ is defined as the angle formed by the idealized surface D-E of second shell 120 relative to the horizontal.

As embodied herein, and shown in Fig. 11a, when shock absorber 100 is loaded with shear force, points E and F maintain their relative positions with respective to the ground surface. The remaining idealized points of shock absorber 100, however, are displaced by the shear force by varying degrees. It is this differential displacement that produces the banking effect of the present invention. Point A moves slightly upward and to the right to position A' and point D moves slightly downward and to the right to position D', as shown in Fig. 11a. The differential dislocation of points B and C, however, significantly alters the orientation of upper surface of shock absorber 100. Point B moves downward and to the right, whereas point C moves upward and to the right, changing the position of upper surface B-C from being oriented substantially parallel to the ground surface to assuming banking angle θ, as shown in Fig. 11a.

In the banked condition, the change in angle β is greater than the change in angle Φ, reflecting the fact that upper and lower shell springs 110 and 120 undergo different degrees of deformation. Upper shell springs 110 is deformed significantly more than lower shell spring 120. Although this effect has been explained with particular reference to an idealized representation of the present invention for sake of simplicity, it will be appreciated by persons of ordinary skill in the art that the effect described above with reference to Fig 11a operates despite variations and modifications in the precise physical configuration of the various elements of the invention. Comparative results

Referring now to Figure 12 through 16, the response of shock absorber 100 is compared to other shock absorbers. Absent reinforcement, idealized shell springs, operating alone, would exhibit a different force-deflection characteristic than does shock absorption system 100 of the present invention. As shown in Fig. 12, idealized shell springs would progressively resist compression only until the applied force became so high that is was sufficient to deform the shell springs 110 and/or 120 from their concave shape. At that point, the ability of an idealized shell spring to resist further compression lessens substantially, exhibiting greater deflection with increasing compression until the shell springs collapse. This response is not acceptable in athletic footwear. The shock absorber should offer progressive resistance to increasing force throughout the full range of mechanical loading of the shoe.

In spite of this drawback of un-reinforced shell springs, they have certain desirable features for use as a shock absorption system in footwear, namely, they are durable, compact, relatively low cost, and easy to manufacture. Of particular interest to the present invention is the ability of a supported shell spring to maintain a substantially constant spring rate over the full range of deflection, up to the point of plastic deformation. In order to exploit the advantages of shell springs, it is necessary to support them to prevent collapse.

As shown in Fig. 13, the shock absorption system 100 of the present invention exhibits a substantial and progressive resistance to applied force across the full range of loading. The progressive resistance to compression is compared to that of McMahon in Figure 16. Figure 16 illustrates that the deflection of the present shock absorption system is significantly lower than that of McMahon under similar vertical force. In certain circumstances, it can be desired to offer constant, or even decreasing, resistance to applied force. The present invention is adaptable for use in these circumstances as well.

II. Fore Midsole Shock Absorption System

Figs. 17 through 24 illustrate various embodiments of the fore midsole shock absorber 20 of the present invention. A fore midsole shock absorption system 20 of the present invention is shown in Figs. 17 through 24 as 20. Fig. 20 illustrates a present preferred embodiment of the fore midsole shock absorber system 20 of the present invention. A transverse cross-sectional view, taken along section line A-A of Fig. 20, of a preferred embodiment of the fore midsole shock absorber of the present invention is shown in Fig. 22 as 20.

As embodied herein and depicted in Fig. 21, shock absorber 20, comprises two principal elements: base 200, and a plurality of annular projections 210. Base 200 further comprises first and second surfaces 202 and 204, respectively, and central and radial margin regions 206 and 208, respectively. In conjunction with first surface 202, each of annular projections 210, forms a shell spring. As shown in Fig. 20, in a preferred embodiment of the present invention, shock absorber 20 is preferably circular in shape. As shown in Figs. 18 and 19, shock absorber 20 is placed in the foresole of a shoe, traversing substantially the full width of fore sole 80.

As noted above, absent reinforcement, shell springs would not increase resistance to increasing stress throughout the full range of loading of the shoe. The present invention overcomes this deficiency by nesting a series of concentric, annular shell springs. The shell springs reinforce one another and maintain the ability of shock absorber 20 progressively to resist increasing force across the full range of compressive loading. As shown in Fig. 14, shock absorber 20 of the present invention exhibits a substantial and increasing progressive resistance to applied force across the full range of loading forces.

Returning again to Figure 21, annular projections 210 each further comprise proximal and distal ends 212 and 214, respectively, and inner and outer surfaces 216 and 218, respectively. Annular projections 210 are nested in radially spaced-apart relation. Preferably, annular projections 210 are constructed of any suitable high durometer material, including high durometer rubber. In a preferred embodiment of the present invention, annular projections 210 are preferably constructed of duPont "Hytrel"™ brand or Atochem "Pebax"™ brand elastomers, or generic polyvinylchloride ("PVC") elastomer. In a preferred embodiment of the present invention, base 200 and annular projections 210 are integrally formed by injection molding. Shock absorber 20 is preferably configured so that it occupies a minimal amount of vertical space in the midsole of the shoe. In a preferred embodiment of the present invention, as shown in Fig. 21, for a size 10 men's shoe, base 200 is approximately 1.5mm thick, and shock absorber 20 is about 5 mm thick and about 93 mm in diameter. Central region 206 of shock absorber 20 can have no annular projections, but preferably has an aperture 260 formed therein, as shown in Figs. 20 and 21, to cooperate with ventilation system 300 of the present invention. Annular projections 210 also preferably are broken at intervals to prevent them from creating a suction effect, as shown in Fig. 20. Similarly compressive means 150 of rearsole shock absorber 100 are preferably broken to prevent a suction from forming.

As embodied herein, shock absorber 20 comprises first, second and third annular projections, shown in Figs. 20 through 23, as 220, 230, and 240, respectively. The precise number of annular projections is not critical. What is important is that the configuration of the shock absorber provide adequate reinforcement to support the foot. In a preferred embodiment of the present invention, six annular projections 210 are used, including four second annular projections 230. Third annular projection 240 is disposed at the radial margin of the shock absorber 20.

In a preferred embodiment of the present invention, and as shown in Fig. 22, central region 206 of base 200 is substantially flat, lacking annular projections. As embodied herein, first annular projection 220 is disposed from second surface 204 of back 200, proximal to the center 206 of base 200, in a direction substantially normal to base 200. As embodied herein, and shown in Fig. 22, first annular projection 220 further comprises proximal and distal ends 222 and 224, respectively, and inner and outer surfaces 226 and 228, respectively. Inner and outer surfaces 226 and 228, respectively, of annular projection 220 are substantially parallel, or as shown in Fig. 22, preferably have a slight taper, reducing in cross-section from proximal 222 to distal 224 ends. As shown in Fig. 22, the thickness of first annular projection at its base, abutting back 200, is about 6mm, whereas the thickness drops to about 2mm at the distal end, for a size 10 men's shoe.

As embodied herein, shock absorber 20 further comprises one or more second annular projections 230. As shown in Fig. 22, second annular projection 230 further comprise proximal and distal ends 232 and 234, respectively, and inner and outer surfaces 226 and 228, respectively. In a present preferred embodiment of the present invention, as shown in Figs. 20 through 23, shock absorber 20 has four second annular projections 230. As are first annular projections 220, second annular projections 230 are disposed from second surface 204 of base 200, substantially concentric to first annular projections 220. As shown in Figs. 20 through 23, each second annular projection 230 is disposed at a progressively larger radial location, so that each annular projection 210 is disposed in spaced-apart relation to its radially proximal neighbor. In a preferred embodiment of the present invention, as shown in Figs. 21 through 23, the cross-sectional dimension of second annular projections 230, generally increases moving outward in a radial direction.

As embodied herein and shown in Figs. 21 through 23, outer surfaces 228 and 238 of first 220 and second 230 annular projections are disposed substantially normal to second surface 204 of base 200. As shown in Figs. 21 through 23, inner surfaces 226 and 236 of first and second annular projections 220 and 230 preferably are disposed at an obtuse angle relative to second surface 204, resulting in the tapering of first and second annular projection(s) 220 and 230.

In a preferred embodiment of the present invention, shock absorber 20 further comprises third annular projection 240. As embodied herein, third annular projection 240 further comprises proximal and distal ends 242 and 244 and inner and outer surfaces 246 and 248, respectively. Third annular projection 240 is disposed from second surface 204 of base 200, substantially concentric and in spaced-apart relation to first and second annular projections 220 and 230, and at a radius greater than the radius of the most radially distal second annular projection 230. As shown in Fig. 21, in a preferred embodiment of the present invention, the cross- sectional dimension of third annular projection 240 is greater than the cross-sectional dimension of the radially most distal second annular projection 230. (Hence, the cross-sectional dimension of each annular projection 210 preferably increases, moving outward in a radial direction from the central region 206 to radial margin 208 of base 200) . As depicted in Figs. 21 through 23, inner and outer surfaces 246 and 248 cf third annular projection preferably are substantially parallel and are both disposed at an obtuse angle relative to second surface 204 of base 200. In a present preferred embodiment of the invention, each of first, second, and third annular projections, 220, 230, and 240, respectively, offer greater resistance to compressive force than the radially-proximal, annular projection. Thus, fore midsole shock absorber 20 offers greater resistance to compression at its radial margin 208 than at central region 206.

In an embodiment of the present invention, shock absorber 20 further comprises packing 280 as shown in Fig. 21. Packing 280 comprises any suitable resilient base material that will provide support for shock absorbers 100 and 20, preferably, a durable, abrasion resistant, flexible, resilient material, such as ethyl vinyl acetate rubber ("EVA"). Packing 280 affords a firm surface for distal ends 214 of the annular projections 210 to abut under compression, as shown in Fig. 21. Distal ends 214 of shock absorber 20 preferably are not fixed mechanically to packing 280, allowing them to move in response to stress. In a preferred embodiment of the present invention, midsole 60 has a recess formed therein to receive fore midsole shock absorber 20. The fiber board and edges of the upper lay directly on the first surface of base 200, as shown in Fig. 21.

In a present preferred embodiment of the fore midsole shock absorber of the present invention, and shown in Figs. 21 and 22, distal ends 214 of first, second, and third annular projections (224, 234, and 244, respectively) terminate in a plane, each abutting packing 280. Alternatively, the distal end of third annular projection 240 could extend from back 200 so that it is abutting packing 280 in the unloaded state; whereas the distal ends 234 of second and first annular projections 230 and 220 terminate progressively at larger distances from a plane 281 defined by packing 280, as shown in Fig. 23, thereby providing additional shock absorption due to the flexing of back 200.

In a preferred embodiment of the present invention, midsole 60 has cavity 295 formed therein, as shown in Figs. 18. Cavity 295 is adapted to receive fore midsole shock absorber 20. Preferably, as shown in Figs. 22 and 23, shock absorber 20 further comprises a locator tab 290 for ease of assembly. To aid in assembly, cavity 295 is adapted to receive locator tab 290, in order properly to orient shock absorber 20 in midsole 60 during construction.

In a preferred embodiment of the present invention, annular projections 210 center the foot in shock absorber 20. The centering function is accomplished by exploiting the difference in compressive resistance of annular projections 210. First annular projection 220 offers less resistance to compression than do second annular projections 230, which in turn afford less resistance to compression than does third annular projection 240. At any intermediate loading state, the resistance of the shell springs is reinforced by the adjoining spring(s) , resulting in a centering force being applied to the foot.

In a preferred embodiment of the present invention, fore midsole shock absorber 20 further comprises flex grooves 250 to increase the flexibility of shock absorber 20, without compromising its ability to cushion the foot and support the wearer. As shown in Figs. 20 and 22, first, second, and third annular projections 220, 230, and 240, respectively, preferably have a series of intersecting flex grooves 250 formed therein. As shown in Fig. 20, flex grooves 250 preferably comprise first and second flex grooves, 252 and 254, respectively. First flex grooves 252 are disposed transverse to the longitudinal axis 55 of shoe 50, and second flex grooves 254 are disposed oblique to the longitudinal axis 55 of shoe 50. In a preferred embodiment of the present invention, as shown in Fig. 22, flex grooves 250 are formed at a depth intermediate between proximal 212 and distal 214 ends of annular projection 210. Alternatively, in another embodiment of the invention, as shown in Fig. 21, flex grooves 250 can be formed at a depth intermediate between proximal and distal ends of the annular projection 210.

It will be apparent to those skilled in the art that various modifications and variations can be made to the fore midsole shock absorber 20 of the present invention, and in particular to base 200, annular projections 210, and flex grooves 250 of the present invention, without departing from the scope or spirit of the invention. For example, as shown in Figs. 18 and 19, fore midsole shock absorber 20 can be elliptical in shape. As a further example, the number, depth, disposition, configuration, etc., of flex grooves 250 can be varied or modified. In addition, flex grooves 250 can be formed on either base 200 or annular projections 210. Further, selection of suitably pliable materials can eliminate entirely the need to use flex grooves. Similarly, certain of the annular projections are so small and subtend such a limited area of the mid-sole of the shoe that they have little stiffening effect on the sole. For example, first annular projection 220 can not require flex grooves. A greater or lesser number of projections can be used, or their configuration, cross-section, composition, etc, . can be modified, provided those modifications are consistent with their shock absorption function. The precise configuration of the inner and outer surfaces and proximal and distal ends of annular projections 220 are also not critical. Alternately, fore midsole shock absorber 20 could be formed in the manner of rear midsole shock absorber 100, namely, of modified shell springs 110 and 120, diaphragm 130, and compressive means 150, as shown in Fig. 24. Thus, it is intended that the present invention cover the modifications and variations of the invention, provided they come within the scope of the appended claims and their equivalents.

III. Ventilation System

A present preferred embodiment of the ventilation system for the rear midsole shock absorber is shown in Fig. 2 as 300. A preferred embodiment of the ventilation system for the fore midsole shock absorber is shown in Fig. 21 as 300. Fig. 2 illustrates a transverse cross-section and view of the heel portion of an athletic shoe in accordance with a preferred embodiment of the ventilation system 300 of the present invention. As shown in Fig. 2, and embodied herein, ventilation system 300 comprises air chamber 310, first and second apertures 320 and 350, respectively, and first and second valve means 330 and 340, respectively. In a preferred embodiment of the present invention, valve means 330 and 340 comprise one way valves of the type shown in Fig. 2 as second valve 340, which are well known in the art. For example, valve means 330 and 340 can be any appropriate durable, one way valve for the control of fluids, liquids, or gasses. In preferred embodiment of the present invention, valve means 330 and 340 are made of Atochem "Pebax"™ brand elastomer. Valves 330 and 340 are constructed of any appropriate material, preferably, a resilient and durable, high durometer plastic or rubber. One way valves 330 and 340 are disposed in midsole 60 so that one valve admits fluid (air or liquid) into the midsole 60, whereas the other valve allows it to exit. Air chamber 310 preferably is formed by the resilient elements of Applicants' shock absorption systems, disclosed above.

First valve 330 is disposed in aperture 320, as shown in Fig. 2, to admit air into the shoe and second valve 340 is disposed in aperture 350, as shown in Fig. 2, to exhaust air from midsole 60. Air typically will not be admitted from second valve 340, located on the outsole 70 of the shoe, as this can introduce unwanted debris, dirt, or fluid into midsole 60. In a present preferred embodiment of the ventilation system 300, rear midsole shock absorber 20 further comprises air chamber sealant means 390. In a preferred embodiment of the present invention, sealant means 390 comprises tongue means 392 and 394 formed on the concave surfaces 115 and 125 of first and second resilient means 110 and 120 at their respective radial margins 124 and 124 as shown in Fig. 8. Diaphragm 130 further comprises groove means 396, which is adopted to cooperate with tongues 392 and 394 to form an air¬ tight seal, as shown in Figs. 2 and 8, when first and second resilient means 110 and 120 are in mechanically coupled relation. As shown in Figs. 2 and 8, air chamber 310 is formed by groove 396, tongues 392 and 394, first and second resilient shell springs 110 and 120, and first and second valve means 330 and 340, respectively. Air chamber sealant 390 means could be further reinforced by employing additional sealant, or interference fitting between its elements, or any other appropriate sealing means. In order to transfer air efficiently, it is desired that the greatest possible midsole area be available for air chamber 310. In addition, as shown in Fig. 7, a valve retainer means 360 can be included to further hold value 340 in place.

In other embodiments of the ventilation system of the present invention, the top valve can be replaced by less costly alternatives. For example, as shown in Figs. 3, 4, 5, 7, and 21, first valve 330 can comprise the interface between insole 190 and first valve aperture 320. In a preferred embodiment of the present invention, insole 190 is any appropriate liner. Insole 190 cooperates with the midsole 60 abutting first midsole aperture 320, closing first midsole aperture 320, effectively forming a one way valve.

It will be apparent to those skilled in the art that various modifications and variations can be made to the ventilation means 300 of the present invention and in particular to the construction of first and second valve means 330 and 340, and to air chamber 310, without departing from the scope or spirit of the invention. For example, one way valves 330 and/or 340 can comprise adjustable valves, allowing the wearer to modify the resistance of shock absorber 100 and/or 20 of Figure 1. By adjusting valves 330 and/or 340 to reduce or increase the amount retained during each compression cycle, the retained air can modify the resistance of the shock absorber to compression. Alternatively, the disposition of valves 330 and 340 can be varied to place them on opposite sides or on the same side of the shoe. Diaphragm 30 could be adapted to function as a valve, for example, the upper valve. Valves 330 and 340 can be any appropriate valve that is sufficiently durable and resilient. For example, valve 330 could be of the type shown in Fig. 2. As a further example, midsole 60 and the upper can comprise one or more bladders to retain fluid exhausted from the air chamber. In certain embodiments the air chamber can be divided into a primary air chamber 310 and secondary air chamber(s) 380, as shown in Fig. 7. Fluid can be supplied to bladders through tubes or other fluid communication means to "pump up" the bladders and further reinforce certain points of the shoe. Fore and rear shock absorbers could also be coupled by a fluid passage. Further, the ventilation system could be adapted to pulse, by expelling the air surrounding the foot and recharging air into the shoe through the upper. Thus, it is intended that the present invention cover the modifications and variations of the invention provided they come within the scope of the appended claims and their equivalents.

IV. Outsole System

An outsole system 40 of the present invention is shown in Figs. 7, 8, 24, 25, and 26 as 400. Fig. 26 illustrates an athletic shoe including preferred embodiments of the outsole system 40 of the present invention adapted for the fore and rear sole, areas of the outsole 70.

As depicted in Figs. 7, 21, 24, 25, and 26, outsole system 40, comprises two principal elements: outsole surface

400 and a plurality of annular outsole projections 410. In a preferred embodiment of the present invention, outsole surface 400 is substantially flat. Annular projections 410 preferably are integrally formed with main outsole surface 400 in a compression molding process. Although the inventors presently believe that compression molding of the outsole is preferred, other suitable molding techniques are also appropriate. The present inventors are aware that certain workers are developing improvements in injection molding techniques that can prove useful in forming the outsole system 40 of the present invention.

Annular projections 410 preferably are centered at the juncture of the ball-of-the-foot and toe portions of the sole in the foresole region 80, and in under the heel in the rear sole region 90 as shown in Fig. 26. As embodied herein, and shown in Figs. 7 and 25, annular projections 410 further comprise proximal and distal ends 412 and 414, respectively, and inner and outer surfaces 416 and 418, respectively. Annular projections 410 are disposed in substantially concentric, nested, spaced-apart relation. As shown in Fig. 26, outsole system 40 preferably extends substantially across the width of sole at both fore sole 80 and rear sole 90 locations.

As shown in Fig. 26, in a preferred embodiment of the present invention, annular projections 410 preferably are constructed of rubber. Annular projections 410 further comprise first, second, and third annular projections, 420, 430, and 440, respectively. In a preferred embodiment of the present invention, as shown in Fig. 26, seven annular projections are used in the fore sole region and five annular projections are used in the rear sole. The precise number of annular projections is not critical, provided sufficient shock absorption and support are maintained. The number, shape, and configuration of projections will also depend on their respective size, cross-sectional area, disposition, and composition. The stronger (in compression and in shear) each annular projection is, the fewer are needed to maintain the same level of performance.

In a preferred embodiment of the present invention, as shown in Figs. 7, 8, and 25, annular projections 410 extend from 3 to 8 mm from sole surface 400 to distal ends 414. Annular projections 410 should be sufficiently wide at their proximal ends 412, where they are attached to sole surface 400, that they will retain their resilience and resist cracking and breaking. In a preferred embodiment of the present invention, as shown in Fig. 26, annular projections 410 are substantially the only projections from sole surface 400.

Selection of appropriate outsole materials is well known in the art and will depend in large measure on the use that is intended for the shoe. If the shoe is to be used on asphalt or concrete surfaces, abrasion-resistant materials are required in order to ensure durability. A shoe that is to be used on wood court surfaces can provide good performance with less abrasion-resistant rubber. For example, outsole materials considered appropriate would range from 50 to 100 Shore A. In a preferred embodiment of the present invention, the durometer rating of the outsole material is preferably 60-75 Shore A.

As noted above, absent reinforcement, shell springs can not be acceptable for footwear. See Fig. 12. As embodied herein, outsole system 40 of the present invention comprises a series of nested, concentric shell springs which reinforce each other and maintain progressive resistance to increasing force across the full range of loading.

In a further preferred embodiment, as shown in Fig. 26, central region 402 has an aperture 460 formed therethrough to work cooperatively with ventilation system described above. First annular projection 420 is disposed proximate to central region 402. First annular projection 420 further comprises proximal and distal ends 422 and 424, and inner and outer surfaces 426 and 428, as shown in Figs. 7 and 25.

Outsole 40 further comprises one or more second annular projections 430, as shown in Figs. 24, 25, and 26. Second annular projection(s) 430 preferably are disposed from the surface of outsole 400, substantially concentric to first annular projections 420. Second annular projection 430 is disposed radially distal to first annular projection 420, and in spaced-apart relation. When more than one second annular projection 430 is used, each additional second annular projection is disposed at a radius greater than that of the preceding annular projection, and in spaced-apart relation to its radially-proximal neighbor.

Returning again to Figs. 7 and 25, second annular projections further comprise proximal and distal ends 432 and 434, respectively, and inner and outer surfaces 436 and 438, respectively. In a preferred embodiment of the present invention, outer surfaces 428 and 438 of first and second annular projections 420 and 430, respectively, are disposed substantially normal to outsole surface 400. Inner surfaces 426 and 436 of first and second annular projections, respectively, are disposed at an obtuse angle, relative to outsole 400. In a present preferred embodiment of the outsole system 40, first and second annular projections 420 and 430 are substantially triangular in cross-section, having rounded distal ends 424, as shown in Figs. 7 and 8. In a preferred embodiment on the present invention, the cross-sectional dimension of second annular projection 430 is greater than the cross-sectional dimension of first annular projection 420. Moreover, where more than one second annular projection 430 is used, the cross-sectional dimension of each additional radially distal second annular projection 410 increases with increasing radius.

In a preferred embodiment of the present invention, outsole 40 further comprises third annular projection 440. Third annular projection is disposed from the outer surface of outsole 400, substantially concentric to first and second annular projections 420 and 430 radially distal from the outermost second annular projection 430. In this manner, first, second, and third annular projections preferably are disposed in spaced-apart relation.

Third annular projection 440 further comprise proximal and distal ends 442 and 444, respectively, and inner and outer surfaces 446 and 448, respectively. In a preferred embodiment on the present invention, the cross-sectional dimension of third annular projection is greater than the cross-sectional dimension of the outermost second annular projection. The cross-sectional dimension of each annular projection preferably increases progressively when moving outward in a radial direction.

As depicted in Figs. 7 and 24, both inner and outer surfaces 446 and 448 of third annular projection are disposed at an obtuse angle relative to outsole surface 400. As embodied herein, inner and outer surfaces 446 and 448 of third annular projection 440 are substantially parallel, or have a slight taper, as shown in Fig. 25, reducing in cross-section from proximal 442 to distal 444 ends. In a preferred embodiment of the present invention, outer surface 448 of third annular projection 440 extends radially beyond outsole surface 400, as shown in Figs. 24 and 25, forming an acute angle relative to the extension of the plane of outsole surface 400 and beyond the lateral margins of surface 400.

In a preferred embodiment of the present invention, annular projections 410 have different lengths, namely, first annular projection is shorter than second annular projection, and second annular projection is shorter than third annular projection. In this configuration, the distal ends 414 of annular projections 410, preferably subtend a conical or arcuate shape in cross-section, as shown in Figs. 7, 8, 21, 24, and 25. Specifically, as shown in Figs. 24 and 25 the distance between proximal 422 and distal 424 ends of first annular projection 420 is preferably about 1mm, for a size 10 men's shoe. Similarly, the distance between proximal 432 and distal 434 ends of second annular projections 430 increases from about 1mm to about 2mm, from the radially proximal to radially distal second annular projections. The distance between proximal 442 and distal 444 ends of third annular projection 440 is preferably about 2.5mm.

Third annular projection 440 is in contact with the surface in the unloaded state. The distance between the surface and each of the distal ends 414 of each of second and first annular projections 410 increases in a radially proximal direction toward central region 402. As outsole 40 is loaded, it flexes, absorbing a portion of the shock, before transferring the force of the shock to annular projections 410, which absorb additional shock by compressing and flexing in turn.

In a preferred embodiment, the outsole of the present invention offers less resistance to compression at the center 402 than at the radial margins 404. Loading of outsole 40 proceeds from the radial margins 404 of outsole 40 toward the center 402. At any intermediate loading state, the resistance of outsole 40 is reinforced by the radially-distal annular projections, working in toward the center, resulting in a centering force being applied to the foot.

In a preferred embodiment of the present invention, outsole 40 further comprises flex grooves 450. As shown in Fig. 26, in a preferred embodiment of the present invention, first, second, and third annular projections 420, 430, and 440, respectively, have a series of intersecting flex grooves 450 formed therein. As depicted in Fig. 26, annular projections, flex grooves 450 preferably comprise first and second flex grooves, 452 and 454, respectively. As shown in Fig. 26, first flex grooves 452 are disposed transverse to the longitudinal axis of shoe 50, and second flex grooves 454 are disposed oblique to the longitudinal axis of shoe 50. In a preferred embodiment of the present invention, flex grooves 450 are formed in annular projections 410 at a depth intermediate between proximal 412 and distal 414 ends of annular projections 410.

It will be apparent to those skilled in the art that various modifications and variations can be made to the outsole system 40 of the present invention and, in particular, to the outsole 400, annular projections 410, and flex grooves 450 of the present invention, without departing from the scope or spirit of the invention. As an example, the precise configuration of the inner and outer surfaces 416 and 418 and proximal and distal ends 412 and 414 of annular projections 410 are not critical. The annular projections 410 can be elliptical, indicated schematically in Figs. 18 and 19. A greater or lesser number of annular projections can be used. Their configuration, cross-section, composition, etc. , can be modified and varied, provided those modifications are consistent with their shock absorption function. For example, the configuration of each projection could be similar but different materials could be selected to achieve a different resistance to force.

For example, the present inventors believe that the performance of outsole 40 can be improved by disposing outer surface 416 of each annular projection at an obtuse angle relative to outsole surface 400 (as shown in Figs. 3-7 and 24) . In this manner, annular projections 410 are undercut, relative to outsole 400. Manufacture of the outsole of the present invention in this fashion, using known molding technologies, is complicated. Nonetheless, with improvements in molding technology, such construction would be available and is within the scope of the invention. Thus, it is intended that the present invention cover the modifications and variations of the invention provided they come within the scope of the appended claims and their equivalents.

Finally, it will be apparent to those skilled in the art that various other modifications and variations can be made to the rear and fore sole shock absorber, ventilation, and outsole systems of the present invention and in the construction of each of their elements, without departing from the scope or spirit of the invention. Thus, it is intended that the present invention cover the modifications and variations of the invention provided they come within the scope of the appended claims and their equivalents.

Claims

We claim:

1. A shock absorption system for footwear comprising: a resilient rear midsole shock absorber; a resilient fore midsole shock absorber; a ventilation system; and an outsole system.

2. A resilient midsole shock absorber system for footwear, comprising: first resilient means, having central and radial margin regions and a substantially concave surface, second resilient means, having central and radial margin regions and a substantially concave surface, said second resilient means disposed with said concave surface in opposition to said concave surface of said first resilient means so that the distance between said first and second resilient means is greater at said corresponding central regions than is the distance between said first and second resilient means at said corresponding radial margin regions; wherein said first and second resilient means are mechanically coupled at their respective radial margins; third resilient means having central and radial margin regions; said central region of said third resilient means further comprising a chord of said corresponding radial margins of said first and second resilient means, disposed substantially between said central regions of said first and second resilient means; said third resilient means being disposed between and mechanically coupled to said first and second resilient means at corresponding said radial margins of said first, second, and third resilient means; and said third resilient means further comprising a tensile means for maintaining the resistance of the shock absorber to compression.

3. The shock absorber of claim 2, wherein said third resilient means further comprises compressive means, disposed between said concave surfaces of said first resilient means and said second resilient means and between said central regions of said first and second means.

4. The shock absorber of Claim 2, wherein corresponding said radial margins subtend substantially an ellipse.

5. The shock absorber of Claim 2, wherein said third resilient means comprises a diaphragm, disposed between said first and second resilient means.

6. The shock absorber of Claim 2 , wherein said shock absorber has means for greater resistance to compression at said radial margins than at corresponding said central regions of said resilient means for centering the foot in the shock absorber.

7. The shock absorber of Claim 2, wherein said shock absorber has means for banking in response to lateral shear.

8. A resilient midsole shock absorption system adapted for use in the fore sole of footwear, comprising: resilient base means further comprising first and second surfaces, and central and radial margin regions; at least one annular projection disposed from said second surface of said base means, having proximal and distal ends; said annular projection subtending substantially said central region of said second surface of said base means; whereby said annular projection and said base means comprise a shell spring; whereby said shell spring absorbs energy and shock applied to the fore sole.

9. The shock absorber of Claim 8, further comprising second and third annular projections; wherein, said second projection is disposed radially distal from said first annular projection and in spaced-apart relation to said first annular projection; said third annular projection is disposed radially distal from said second annular projection and in spaced-apart relation to said second annular projection; said third annular projection extending substantially across the width of a sole subtending lateral margin regions.

10. The shock absorber of Claim 9, wherein said annular projections further comprise a radial, cross-sectional dimension, and wherein said radial, cross-sectional dimension progressively increases from said first through said second, and third annular projections.

11. The shock absorber of Claim 9, wherein said annular projections further comprise materials having different resistance to compression.

12. The shock absorber of Claim 9, wherein said spacing of said annular projections has means for increasing progressive resistance from said first through said third annular projections.

13. The shock absorber of Claim 9, wherein said annular projections further comprise a plurality of cross-hatched flex grooves formed therein, for increasing the flexibility of the shock absorber.

14. A ventilation system for footwear having a midsole with transverse and a longitudinal directions, comprising: resilient compression means disposed in the midsole in substantially parallel relation to a plane of the midsole; said compression means further comprising, first and second resilient means, said first and second resilient means having a first aperture, wherein said first and second resilient means are mechanically coupled comprising a substantially air-tight seal; valve means cooperating with said first aperture for controlling the flow of fluid through the ventilation system; wherein fluid is exhausted from said compression means when the midsole is placed in compression by the foot and wherein fluid is admitted into said compression means when said foot pressure is released.

15. The ventilation system of Claim 14, further comprising first and second valve means and a second aperture, said first and second valve means being disposed in said first and second apertures for controlling the flow of fluid through the ventilation system.

16. The ventilation system of Claim 14, wherein said footwear further comprises two of said ventilation systems, and has a fluid exchange means in communication between said two ventilation systems.

17. The ventilation system of Claim 14, wherein said footwear further comprises a fluid chamber, and fluid exchange means in communication with said compression means and said air chamber, for transmitting fluid between said compression means and said fluid chamber.

18. The ventilation system of Claim 14, wherein said compression means is adapted to retain substantial fluid under compression, for cushioning the foot.

19. The ventilation system of Claim 14, further comprising an adjustable fluid control means for controlling a rate of exhausting fluid from said compression means.

20. An outsole system adapted to absorb shock, for footwear having a main outsole surface and one or more annular projections comprising: a resilient outsole surface further comprising first and second surfaces and central and lateral margin regions; at least one annular projection disposed from said second surface of said outsole surface, said annular projection further comprising proximal and distal ends; said proximal ends corresponding the point where said annular projection is disposed from said outsole surface; said projection subtending substantially a portion of said central region of said second surface of said sole; whereby said annular projection and said outsole comprise a shell spring for absorbing energy and shock.

21. The outsole system of Claim 20, further comprising second and third annular projections, wherein said second projection is disposed radially distal from said first annular projection and in spaced-apart relation to said first annular projection; said third annular projection disposed radially distal from said second annular projection and in spaced-apart relation to said second annular projection, said third annular projection extending substantially across the width of the sole, whereby said third annular projection subtends a portion of said central region and of said lateral margins; and wherein said outer annular surface of said third annular projection extends beyond said lateral margins of said outsole and said outer annular surface of said third annular projection is disposed at an acute angle relative to the extension of the plane of said surface of the outsole beyond said lateral margins.

22. The shock absorber of Claim 21, wherein said annular projections have a progressively larger radial, cross- sectional dimension from said first through third annular projections.

23. The shock absorber of Claim 21, wherein said annular projections have a progressively larger radial, cross- sectional dimension from said first through third annular projections, for increasing progressively the resistance of the shock absorber to compression.

24. The shock absorber of Claim 21, wherein said annular projections have a progressively larger radial, cross- sectional dimension from said first through third annular projections, for centering the point of greatest stress of the foot over said central region of said annular projections.

25. The shock absorber of Claim 21, wherein said annular projections further comprise materials having different resistance to compression.

26. The shock absorber of Claim 20, wherein said annular projection further comprises a plurality of flex grooves formed therein, for increasing the flexibility of the shock absorber.