CA2162053C - Shoe sole component and shoe sole component construction method - Google Patents

Abstract

A high polymer resin material is configured into a shoe sole component having a plurality of inwardly extending indentations in one or both of the top and bottom members of the component. The indentations extend into the interval between the members and adjacent to the opposite member to provide support members for the sole component. The sole component can be constructed by molding upper and lower sole component halves wherein the molds are configured to provide indentations in the top and bottom members. The upper and lower sole component halves are then joined to complete the sole component.

Description

SHOE SOLE COMPONENT AND SHOE SOLE COMPONENT CONSTRUCTION METHOD
This application is related in part to Canadian patent File No. 2,120,030 issued January 22, 2002.
The present invention relates to shoe soles and shoe sole components and to methods of manufacturing shoe soles and shoe sole components. More particularly, the invention relates to a flexible high polymer resin shoe sole or sole component and a method of thermoforming a shoe sole or sole component.
A shoe generally consists of two basic parts, an upper and a sole. The upper is generally designed to enclose and provide cushioning to the foot. The upper also typically includes an insole to provide initial support and cushioning to the bottom of the foot. The upper is attached to a sole which provides additional protection and cushioning primarily to the bottom of the foot. The sole also imparts stability to the shoe.
The increase in demand for shoes for sports and outdoor activities such as walking, running, hiking, tennis, basketball and numerous other high activity sgorts JVnJJ 1V W nawv.rw..~....~_.~~....~~ ~~~ ~~~ __ .-wo 9ana896 ' PCTJ'US94/048'73 r.:.
has prompted many advances in shoe design to provide improved protection and comfort to the feet, ankles, legs, :.
hips, etc. Efforts to improve shoes have centered on decreasing shoe weight and improving cushioning, flexibility, and stability. zn addition, shoe soles are ' desired with improved memory, shock dispersion.capabilities and energy return.
The effort to design improved shoes has prompted ~0 increased study of foot dynamics in general and the study of foot dynamics as it relates to particular activities such as running, basketball and other specific activities.
The combination of research and research responsive shoe design has resulted in shoes designed for specific ~ activities. For example, the pressures exerted by a foot on a sole when walking are different from the pressures exerted by a foot when running, or when playing tennis, etc. Accordingly, the modern sport shoe design takes into account the specific xequitements of shoes used for 2o particular activities. In addition, modern sport shoe design attempts to take into account the specific needs of the individual, such as weight, foot width and other individual characteristics such as pronation arid supination. Thus, general considerations such as shoe z5 weight, cushioning, flexibility and stability are takeh into account in designing sport shoes for particular activities and individual needs. Although the funct~,onal characteristics of the shoe are of primary importance, other factors such as cost and appearance of the shoe must 30 be taken into account for full consumer satisfaction.
Sport shoe refinements have concentrated particularly on the sole. Sport shoe soles typically have two components, the midsole and the outsole. The outsole is 35 the ground-contacting portion of the sole and provides traction and protection to the remainder of the sole.

WO 94/24896 ~ ~ 16 ~ ~ 5 ~ ' PCTlUS94104873 Outsoles, accordingly, are Composed of durable materials, such as rubber, which provide both traction and high abrasion resistance. The midsole contributes to foot stability and is the primary shock absorption member of the sole. The midsole is composed generally of a softer, more flexible material than the outsole_ Since the midsole is important to such factors as stability and shock absorption, the design of the midsole has received considerable attention by sport shoe manufacturers.
, ..
Typically, midsole construction centers around plastics expanded into foams which are then shaped in a numbez of ways to accommodate a shoe upper. The foam midsole is then covered with a more durable sheet of outsole material, usually rubber, to provide the sole with adequate abrasion resistance and traction_ Attaching an .
outsole to a foam midsole is generally a laboz-intensive process. For example', attaching a rubber outsole to a m~.dsole requires abrading the surface of the midsole, z0. washing the surface with a solvent, layering both the midsole and outsole surfaces with cement where they are to be joined, then activating the treated surfaces, usually with heat. This ,is followed by touch-up and decoration processes. ' A foam midsole material by itself is generally inadequate to provide the stability and Cushioning demanded for modern sport shoes. The foams used in current sales have insufficient external surface tension by themselves to provide the required stabilizing forces in response to pressures exerted on a so7.e_ This is especially true with extremely low density foams employed tv minimize weight.
Moreover, curz~ent foam midsoles quickly lose their ability to adequately cushion, often after ag little as zoo of the shoe life.

.. '.
WO 94!?~1896 ~ ' pCTlLTS94104873 The problems of stability and cushioning associated with the use of foam midsoles has prompted several approaches for increasing stability and prolonging the cushioning properties of. midgoles. Efforts to improve stab~.lity have centered on the use of inserts of denser, ' more rigid materials than the main mideole component, such -as dense foam plugs or solid thermoplastic inserts. These are either inserted directly into the foam midsole component before curing or cemented into p7.ace afterwards .' in another labor-intensive process. Efforts to improve cushioning while maintaining adequate stability have centered on the use o~ flexible thermoplastic inserts and liquid yr gas filled inserts. These insez~ts also are generally encapsulated in the main midsole component. .' 15~ Thus, modern sole design has centered on constructing soles -having varying degrees of flexibility in selected areas of _.
the sole. For example, ~.nsex~ts can include foamed plugs of material harder or softer than the main midaole component.
As stated, the inserts are typically encapsulated in the ZO midsole material to provide areas in the mideole of lesser -flexibility where increased stability is desired, and az~eas -of greater flexibility where increased cushioning is '.' desired. Other approaches include the use of resilient -spheres embedded in the midsole by casting or injection z5 molding the midsole around the spheres. Trampoline devices incorporated into the heel region of shoes have been attempted, but cost and appearance factors have limited the use of this concept. various gels and gases have also been incorporated into midsoles in an attempt to enhance and 30 prolong cushioning and energy return_ However, soles incorporating gels or gases such as air are costly to manufacture and relatively unpredictable in their .:
functional characteristics.
35 Midsoles have also been constructed of a shell of a thermoplastic elastomer designed to encapsulate and protect _5_ low density synthetic foams uch as polyether, polyurethane or polyester polyurethane. Increased rigidity along the periphery of the sole is provided by convolutions in the shell material along the edge of the sole. Plugs of denser foam are still incorporated into the main foam component where more rigidity in the inner foam component is desired. Moreover, such shells are generally made by blow molding the thermoplastic material. Blow molding involves costly molds, which limit the size and number of design changes.
Additionally mold costs became a significant factor when the number of shoe sizes for each shoe model is taken into account.
This is reflected in higher sole wait costs. Thus, shoes manufactured by blow molding techniques are limited to higher priced shoes although the gain in performance over traditional sport shoes employing foam midsoles is not particularly significant since the interior of the shell sole is still composed of foam which breaks down and loses its cushioning effect in a relatively short period of time. Because of the cast involved in manufacturing such soles, their use has been limited primarily to heel components. Accordingly, shoe sole components are desired having improved performance and cost effectiveness.
The invention in one broad aspect provides a shoe sole structure, comprising a flexible sole-shaped top sheet of thermoplastic and having a plurality of indentations therein and a flexible sole-shaped bottom sheet of thermoplastic and having a plurality of indentations therein., the bottom sheet joined at its periphery to the top sheet to form a cavity therebetween. The indentations in the top sheet have sufficient depth to form projections extending inwardly into the cavity to abut indentations in the bottom sheet to retain the top member and bottom member in spaced relationship, each indentation forming a recess facing outwardly, at least one of the indentations in the top sheet or bottom sheet being hemispherical in shape.
Another aspect of the invention provides a shock absorbing apparatus, comprising a first flexible high polymer resin sheet having an outer periphery and a plurality of hemispherical shaped indentations therein and a second flexible high polymer resin sheet coextensive with and attached to the first sheet and having an outer periphery and a plurality of hemispherical shaped indentations therein. At least one hemispherical shaped insert is configured for insertion into a hemispherical shaped indentation in the second sheet and a cavity is between the first sheet and second sheet, the cavity coextensive with the first and second sheets, each of the plurality of hemispherical shaped indentations in the first and second sheets having sufficient depth to project inwardly into the cavity and having a recess facing outwardly.
Still further the invention comgrehends a shoe sole structure comprising a flexible top sheet having a plurality of indentations therein, a flexible bottom sheet having a plurality of indentations therein, the indentations in the bottom sheet abutting the indentations in the top sheet and a plurality of the indentations in one of the sheets having a hemispherical shape.
A plurality of hemispherical shaped inserts are insertable into the hemispherical shaped indentations and conform to the surface of the indentations with a web-like structure linking the inserts to each other.
More particularly, disclosed is a shoe sole component comprising a sole component body member constructed from a flexible high polymer resin. The sole component is characterized by a top foot-platform member which can be directly or indirectly connected to a shoe upper. The component further comprises a corresponding bottom member which can be used either as the ground contacting member or for attachment to an outsole material. Internal support members for the sole component are provided by indentations in one or both of the top and bottom members. The indentations extend into the interval between the top and bottom members and can contact or bridge with the opposite ~1~~~~~
'VYO 94!2d896 . .. pCT/04873 component member. The support members formed by the indentations in the flexible .sole component material ..
provide flexible resistance to compressive forces exerted ' on the sole component. The component can also include a wall member coextensive with the top and bottom members.
The shoe sole component can be constructed through molding sheets of plastic resin in molds configured to form .' shapes for incorporation into shoe soles and with to protrusions to provide the indentations in the material for the support members. One mechanism for forming the sole component of the present invention is through thermoforming. Generally, thermoforming is a process of shaping plastic resin by heating a sheet or film of the ~ plastic to a temperature at which the resin is sufficiently pliable to be shaped into a desired form and then foxcing the material into a one-sided mold_ The sole component of the invention is preferably constructed by (1) heating a ;-first thermoplastic sheet to its form~.ng temperature, '.

(2) heating a second thermoplastic sheet to its forming temperature, (3) forcing the first thermoplastic sheet into a first mold configured to provide an upper sole component half having a top foot-platform member and forcing the second thermoplastic sheet into a second mold configured to 2S provide a lower sole component half having a bottom member, and (4) joining together the two molded halves by bonding, gluing, welding, fusing, coupling or the like. The mold halves are configured to indent either or both of the top and bottom members at selected points to provide internal 3o support members. A particularly preferred construction method is to close together the mold halves while the material is at its forming temperature such that the sole component halves are fused or welded together at their contact points.

WO 9d1Z4896 PCTIrJS94104f13 _7_ The support members can be thermoformed into a variety of shapes and sizes to provide specific areas of differing degrees of flexibility for stability and cushioning. For example, inwardly direpted,indentations can take the shape of coral-shaped pins which extend from either the top or bottom member and engage the opposite member. The pins can be gzouped closer together where greater resistance is required for areas where a foot exerts the greatest pressure such as in the fozefoot and heel regions of the 7.o sole. Pins can be grouped further apaxt or replaced by .
larger support members in weight bearing areas to increase cushioning. Support members can also be provided by indentations from the top foot-platform member extending into and contacting a corresponding indentation from the 15~ bottom member. The corresponding indentations can be fused or welded together during the thermofoz~ming process to provide an internal support member combination bridging the top and bottom members of the sole component.
2o In addition, forming the sole component from two sheets of thermoplastic resin allows the sole component to be constructed of two different materials having different properties to create a variety of functional responses difficult to achieve through the use of only one material_ Z5 For example, the bottom member can be constructed of a thermoplastic which is thicker, and accordingly stiffer, while the top member is constructed of a thermoplastic which is thinner and more flexible. In addition, support members constructed by corresponding indentations extending 30 from the top and bottom members made of different materials cars provide supporC members having dual properties. For example, the lower portion of the support member provided from the stiffer thermoplastic material will provide a stiffer support member portion and thus wi~.l gro~ide 35 greater resistance to forces exerted on the bottom portion of the sole. The upper portion of the support member WO 9x124896 PCTIUS9~104873 _g_ constructed from the indentation of the thinner, more flexzble material will exhibit greater flexibility, and accordingly provide more cushioning in response to pz~essures exerted on the top member of the sole component.
By varying the shapes and sizes of the support members and ' the properties of the thermoplastic materials employed, the designer can control stability and cushioning characteristics throughout the sole component.
1o FIG. 1 is a aide view of an athletic shoe having a sole component according to one embodiment of the present invention.
FIG. 2 is an exploded view of the athletic shoe shown 15~ in FZG. 1.
FIG. 3 is a top plan view of the sole component embodiment shown is FIG. 2.
20 FIG. 4 is a bottom plan view of the sole component embodiment shown in FZG. Z.
FxG. 5 is a perspective view of enjoined sole component halves showing the internal structure of the sole 25 component embodiment chown in FIG.~Z..
FIG. 6 is a cross sectional view of the sole component embodiment taken along line 4-4 in FIG. z.' 30 FIG. 7 is a cross sectional view of the sole component embodiment taken along line 5-5 in FIG. 2. .
FzG. a is a perspective view of enjoined internal support members according to one embodiment of the present _ 35 invention.

_ w. ~,~~2~~3 WO 94!2d896 PCT/US9a/04873 FIG. 9 is a perspective view of joined internal support members illustrated in FZG, e.
FIG. 10 is a perspective view of one embodiment or the .
S present invention showing a cup sole embodiment.
FIG. 11 is a schematic illustrating a twin-sheet -thermofoz-~ning process .
l0 FIG. 12 is a perspective partial cutaway exploded view of a sole component mold, corresponding lower sole component portion and outsole members according .to one embodiment of the present invention.
15' FZG. 13 is a perspective view of the lower half of the sole component with outsole members according to the embodiment of the present invention shown in FIG. 1Z.
FIG. 14 is a cross sectional view of the mold 2o illustrated in FIG. 12 ~thowing an outsole member recessed in the mold and in locking engagement with sole component material.
FIG. 15 is a cross sectional v~.ew of an outsole member 25 having a plurality of protrusions in locking engagement with sole component material.
FZG. ~,6 is a bottom plan view of a shoe upper showing one half of an attachment means according to one embodiment .
30 of the present invention.
FIG. 17 is a top plan view of a sole component accozding to one embodiment of the present invention showing the corresponding attachment means illustzaced in 35 SIG. 11.

wo 9arza896 J ~ ~ ~1 ~ ~ ~ ~ ~ ,~ rcxrus9aioas~r3 -lo-FIG. 18 is a side cross sectional view of the shoe upper and sole component attachment means illustrated in FIGS. 16,17.
FIG. 19 is a bottom plan vie~r of a shoe upper according to one embodiment of the present invention showing one half of one alternative attachment means.
FIG. 20 is a top plan view of a sole component l0 according to one embodiment of the present invention showing the corresponding attachment means illustrated in FIG. 19.
FIG. 21 is a side cross sectional view of the shoe 15~ upper arid sole component attachment means shown in FIGS.
19-20 . .-FIG. 22 is a perspective view o~ the top and bottom shoe sole components joined together according to a second 20 preferred embodiment of the invention.
FIG. 23 is a perspective view of the inwardly directed indentations and hemispherical inserts in the heel portion of the bottom member of FIG. 22, ' FIG. 24 is a perspective view of a portion of the shoe sole components of FzG. 22, with insezts adapted to be inserted in the inwardly directed indentations of the bottom member.
FIG. 25 is a section view of the shoe sole components of FIG. 22, with a hemispherical shaped insert positioned in an inwardly directed indentation in the bottom member.
The present invention is a shoe sole component made of a flexible high polymer plastic resin. The sole component ' .. ~~~~0~3 WO 94/Z4896 ~ . . PC'1'1US94104873 can cvmpri~e the entire shoe sole or a portion of the sole such as a midsole, heel section, arch section or forefoot section. Depending on how the component is used, the component's general shape is configured for incorporation into a shoe sole. For example, if the sole component .
comprises the entire shoe sole, the cordponent is configured to cooperate with a shoe upper, e.g., the sole is shaped to match and to accommodate a shoe upper. If the component comprises a portion of a sole, the component is configured _:
to cooperate with the other portions of the sole to complete the sole. For example, the sole component can form the heel portion of a sole in conjunction with other sole materials such as traditional ethylene-vinyl acetate '"
copolymer tEVA) foam midsole portions and outsole 15~ materials. If the sole component is a midsole, the midsole is configured to accommodate a shoe upper and an outsole.
The sole component generally consists of one or more high polymers, generally synthetic, which can be molded or ..
formed by heat and pressure. Preferably, the high polymers are thermoplastic polymers or thermoplastic polymers which can be made into thermoset polymers following molding. The polymer is formed into a body member configured for use as a shoe sole or as a portion of a shoe sole. Regardless of ,the specific role of the sole component, the body member generally comprises a top foot-platform membez~ and an opposing bottom member. The top foot-platform member is the surface of the body member oriented towards the shoe upper_ Other various intermediate materials can be ' disposed between the top member and the upper. The body member further compzises a bottom member which .is the portion of the component body member oriented towaz~ds the ground-contacting portion of the sole. The bottom membez is in at least partially coextensive relation to the top member_ The coextensive relation between the top and .
bottom members defines corresponding portions between the 1~~~~~
WO 94124896 PCT/US94l04873 top and bottom members. Moreover, the cop and bottom members are disposed in at least partially spaced relation to each other. Fvz~ example, where the body member is to function as a sole or midsole component, the top and bottom members are spaced apart in a generally parallel planar ' relationship from the heel region through the mid section of the component. However, as the top and bottom members .
extend through the forefoot region, the members can taper towards each other and eventually meet. In any event, the members are at least in partially spaced relation to one another such that the spaced relation defines an interval between the top and bottom members.
Disposed in the interval between the top and bottom ~ members are a plurality of support members. The support members are comprised of inwardly directed indentations in one or both of the top and bottom members. The indented portions of the body member extend into the interval to a point adjacent the corresponding portion of the opposite member. Adjacent as used in describing the present invention means that the indentation extends to a point which is at least proximate the corresponding portion of the opposing member and can be engaged with the opposite '.
portion. The engagement can be fixed or z~on-fixed. In one z5 embodiment of the present invention, one ox more of the support members are fixedly engaged or are joined to the corresponding portion of the opposite member to retain the -top and bottom members in their coextensive and spaced relation. In another embodiment of the present invention, the top and bottom members can be retained in their spaced and coextensive z~elation by coupling members extending between the top and bottom members. In this instance, support members can be in a fixed or non-fixed relation as .
design criteria indicate.

_ ~~~20~3 -WO 9d124896 P(."fIU59d104873 In another embodiment of the present invention, the body membez~ further comprises a wall member which is -coextensive with at least a portion of the periphery of the ton and bottom members. ,In this embodiment, the wall member can j pin the top and bottom members to retain the members in their spaced and coextensive relation.
Moreover, where the wall member is continuous along the periphery of the top and bottom members, the cooperation among the top, bottom and wall members serves to define a .
1o shell having internal support members formed from inwardly -directed indentations extending into the shell interior and adjacent to corresponding portions of the opposite member.
As indicated, the suppoxt members are integral 15~ portions of the sole component comprising inwardly directed indentations in the polymer materials fozming the top and bottom members of the sole component. The support members provide mechanical levers which provide a controlled collapsing of the material to create areas of cushioning 2o and stability in the component. The support members are configured to extend into the interval between the top and bottom members and adjacent the opposing corresponding portion. The indentations can be formed in one or both of ' the top and bottom members. Moreover, the opposing 25 corresponding portion can itself, be an inwardly extending indented portion. In this instance, the opposing - -corresponding support members extend into the interval and adjacent to one another. Again, the corzesponding indented portions are at least proximate to one another arid can be 34 engaged with one another in a fixed or non-fixed relation.
The indented portion of the top or bottom fiembers can be to -any extent which retains enough of the cop and bottom members' non-indented surface area to provide adequate .
support for use as a sole component. For example, 35 components having an indented portion of about SO% are -coraemplated. To further illustrate the invention, 21~~~~3 ' v WO 94124896 PCT/US94l04873 reference is made to a preferred embodiment wherein the .
sole component is a midsole portion o~ a shoe sole.
Referring to Ff.gs . 1-Z , a shoe l, such as a typical running shoe, is shown having an upper z and sole 3. The shoe upper has a lower surface configured for cooperative engagement with the sole. A$ indicated, the sole comprises a midsole 4 and outsole portions 5. The midsole is configured to cooperate with the sole engaging surface of l0 the shoe uppex. In the embodiment illustrated, the midsole 4 is a shell comprising a Cop foot-platform member 6, a bottom member 7, and a wall member 8. The top and bottom members are in generally parallel planar relation tv each other in the heel and mid section of the sole, tapering 15~ towards each other as the midsole pzogxesses towards the forefoot region and on to the front portion of the midsole where the top and bottom members meet. The tap and bottom .
members are in coextensive relation and are partially spaced apart from one another to define an interval between _ 2o the top and bottom members. The contiguous wall member a j oins the edges of the top and bottom members to form a shell having an interior space. A plurality of inwardly directed indentations 9 in the top and bottom members extend towaxd and adjacent to the opposite member and serve 25 to provide internal support to the sole component structure. As indicated, the indentations can be in vne or both of the top and bottom members.
Figs. 3-4 showing top and bottom members, Fig. 5 3o showing unjoined sole component halves, arid Figs. 6-7 showing cross sections of the midsole 4 taken along lines ., 4-4 and 5-5 as shown in Fig. 2, further illustrate the inwardly extending support members. As illustrated, the indentations can take a variety of shapes far forming 35 internal support members. In. the forefoot region are .' indented copal-shaped pins l0, extending from the top WO 94124896 ~ .~~'~ . PC1'1US941oa873 member 40, and corresponding canal-shaped pins 11 extending from the bottom mertber 41, which extend into the interval between the top and bottom members. Channels extending across the forefoot region form flex grooves 12 in the upper sole component half and corresponding flex grooves 13 in the lower sole component half. The flex grooves l2,and 13 also cooperate in the inferior of the sole component to form ribbed support members when the component halves are joined. In the arch region or mid section of the sole component, inwardly extending copal-shaped pins 14 extend toward and cooperate with platform member 15. Platform member 15 is formed by an indentation in the lower sole component half. The heel region is~shown having a large pin member 18 extending inwardly from the upper sole component half towards a corresponding pin member 19 in the lower sole component half. Inwardly extending channels 16 and 17 in the upper and lower sole components halves also cooperate to form internal ribbed support members extending -from the lateral portions of the mid section of the sole component reazward around the large pin members 18 and 19. -In the embodiment illustrated, the large pin/pin arrangement cooperates with the concentrically arranged channels to form a "donut" in the heel of the sole component. The sidewall member 8 is shown having vertical -convolutions 20 which cooperate with corresponding convolutions 21 along the periphery of the lower component -half to provide additional structural support along the .
component's periphery.
As illustrated, support members can cooperate by the contact betweeri corresponding indentations in the upper and lower sole component halves. Fige. 8-9 illustrate a contact point between two indented materials to form coope=sting support members in accordance with one embodiment of the pxesent invention when the upper and lowez~ sole component halves, such as those illustrated in v ~16~~~3 WO 9~/Z4896 PCTIUS94/04873 Figs. 3-7 are joined. Referring to Figs. e-9, upper copal-shaped member 10 formed in the upper sole component half 40 is contacted with a corresponding copal-shaped member 11 ' formed in the lower sole component half 41_ The point of contact can be fixed or non-fixed. if fixed, the ' indentations can be joined at their contact point such as by gluing, fusing, welding or the like.
In some instances the inwardly directed indentations to touch or rest against the opposing sole component member or corresponding indentations in the opposing sole component member, but are not attached or joined to the cozresponding points on the opposing member. For example, pins 14 in the arch area of the top member can extend into the sole ..
~ interior towards and proximate to the indented platform 15 in the bottom member, but remain detached from the .
platform. In some instances the design might indicate that indentations not engage the opposite membex until a sufficient amount of pressure is applied vn the top or 2o bottom sole component member to cause contact between the indentation and the corresponding opposite member portion.
Taking into account the general physical properties of the thermoplastic matErials employed, the size, type and grouping of support members are determined by the functional requirements of the intended sole. For example, the pressure exerted by a foot on a sole is at the highest under the ball of the foot and under the heel.
Accordingly, materials, support members, and location of support members are selected to provide more cushioning and stability in these areas of the sole. Similatly, areas of the sole requiring more rigidity employ materia~.s, support members, and support member locations which provide increased stiffness or rigidity. For example, Dins can be grouped closer togethex where foot pressures on a sole would be expected to be greatest and consequently more - ~ -WO 941?A896 - PCT/U89d10a873 resistance is requited. Another example is the use of different support member shapes in conjunction with each other to provide precise areas of cushioning and support.
For example, pins can ,be made larger in areas where foot ,' pressures are greatest, such as in the heel region of the sole, to provide a mute cushioned heel striking location. ' The cushioned heel strike area can be surrounded by smaller, more densely grouped pins, or by a ribbed support member, to pzovide increased heel stability at the l0 periphery of the heel region_ Lateral stability can be enhanced by the addition of walls extending upward along the pez~iphery of the top member. For exatttple, referring to Fig. Z0, a cup sole formed by the addition of walls 22 and Z3 can be molded into the sole component to provide an integrated sole component having added lateral support for activities such as tennis. .
As stated, the polymers selected for constructing the present invention must be flexible enough to funotion as a z0 sole component. Generally, flexible means the shaped polymer component will bend or give in response to an applied ~orce without cracking or breaking in its hardened state. Particularly preferred polymers for use in the present invention are elastomers which have high elongation. In general, the greater the elongation the greater the flex life and resilience of the sole component.
Good elongation properties are also desirable to create an adequate range of cushioning in the sole, as well as creating the immediate comfort for which athletic soles have become known. For example, polymers with an elongation at break of about 250% to about 300% or more as ~ -measured according to ASTM D 638 are representative of desizable polymers for use in the present invention.
Preterab~,y, the sole component will have a flex life of about at least 50,000 flexes. An indicator cf such desirable flex life can be determined, for example, by the WO 9d12d896 PCTIUS9d/0df13 use of flexing machines.such as the Satra/Bata belt flexing ..
machine manufactured by Satra Footwear Technology Centre, Kettering, Northhamptonshire, Sngland. In actual use, preferred sole components. should withstand at least about S one million foot strikes. ' In addition, the hardness of the material is important to desirable sole component characteristics such as sole integrity, lateral stability, etc. In addition, harder to materials permit the use of thinner materials for constructing the sole component and thus decrease the weight of the component. Generally, preferzed polymers will have a hardness ranging from about 70 on the Shore A
scale up to about 55 on the Shore D scale (ASTM D 2240 ) .
15 . Other preferred characteristics of the sole component ' material are: (1) formability, i.e., the ability of the ..=
material to be molded into the desired component shape, (2) abrasion resistance, (3) clarity, (4) goad tear strength, (5) low density, (6) good tensile strength, 20 (7) the ability to integrate the material into existing footwear manufacturing methodology, (e) the ability to color the material, and (9) cost. High tensile st=ength is desired for coping with high shear forces encountered during high activity use such as running. In addition, 25 high tensile strength permits the sole to be molded thinner. Clarity is important in achieving sharp color contrast, which is vital to acceptable sole decoration.
Transparency is another consideration where the cosmetic .
design of the shoe includes a transparent portion of the 30 sole as fashion and industry trends might dictate. '.
Integration into existing footwear manufacturing processes includes such factors as ease of cementing the component to other shoe materials.
35 As indicated, the sole component is preferably constructed of a thermoplastic resin. Preferable materials _ w ~1'~Q~3 ~ .
WO 94/24896 pCTIUS9d/04g~3 ate those which a,re easily thermoformable into desired flexible sole component configurations_ Materials which can be thermoset after molding and retain the flexible characteristics for the sole components of the present invention ate included within the scope of prefezred ther~noformable materials . Thermoset resins solidify or set irreversibly when heated due to crosslinki.ng between the polymer chains. Crosslinking can be achieved by using nucleating agents, mold temperatuzes above the materials l0 forming temperature, radiation, etc. A thermoset resin once set or cured cannot be softened again by heating.
Thermoset resins ate genezally characterized by high thermal stability, high dimensional stability and high . rigidity and hardness and include resins such as polyesters z5 and urethanes.
Thermoplastic resins ran be either crystalline or amorphous and can be repeatedly softened by heating.
Amorphous thermoplastics include acrylonitzile-butadiene-20 styrene (AHS) copolymer, styrene, cellulosics and polycarbonates. Crystalline thermoplastics include nylons, polyethylene, polypropylene and polyu=ethane. Examples of particularly preferred materials for use in the present invention include thermoplastic polyurethanes, nylons, 25 polyesters, polyethylenes, polyamides and the like.
The fol7.owing descriptions further illustrate the types of desirable materials for use 'in the present invention. Thermoplastic polyurethanes exhibit good flex 30 life, especially at higher hardnesses, good abrasion resistance, cementing ease, good elongation and clarity. -.
Examples of particularly preferred thermoplastic polyurethanes are the Elastollan~ 1100 series of polymers manuf actu~c'ed by BASF Corp . . Parsippany. Ne~.r Jezsey .

WO ~'g~316 PCThIIS9410d893 _20_ Properties of representative Elastoilan~ polymers are provided in the table below.
Y
aR~n~s PROPERTY ASTM UNZTS

Specific D~792 gr/ce 1.13 1.16 1.19 Gravit Hardness D-2240 Shore 4at2 5312 732 D

Tensile D-412 MPa 32 40 40 Stxen th 81on3ation D-412 ~ 575 460 350 ~ Break Abrasion D-1044 trig 45 ?5 ?5 Resistance Nylons exhibit good tensile stzeagth and thus can be molded thinnex. In addition, they have low density, and are therefore lighter, and exhibit good flex life. An example of a preferred nylon polymer far use in the present invention is ZytelTM714 max~ufactured by E.I. DuPont de Nemouza ~ Co., Wilmington, Delaware. Representative Properties of Zytel 714 are provided in the following table:
_~~"~_~

Specific D-792 grlcc 1.02 Gravity Hardness D-2240 Shere D~ 55 Tensile D-638 Mpa 27.2 Strength Elongation D-638 % z60 ~
Break polyesters exhibit good low density, cementing ease, tensile strength and elongation. An example of preferred polyester polymers are various polymers of the Hytrel wo 9e~ss9s .~ctvs~ro~73 series of thermoplastic elastomers manufactured by E.r.
DuPont de Nemours and Compaxaty. Hytrel polymers are block copolymers of polybutyle~ne terephthalate and long-chain =polyether glycols. Properxies of repreaenCative examples S of Hytrel polymers are provided in the follo~rring table:
GRADES

PROPERTY ASTM UN'IT$ 4056 5555HS G-4774 specific D-792 gm/cc 1.16 1.16 1.20 C3ravi. ty Hazdnees D-2240 Shore 40 55 D

Tensile D-638 MPa 28 40 20.7 Strength Elongation D-638 % SSO 500 27S

Break Polyamides exhibit good tear strength, high resilience, low density, goad flex life and clarity. An example of a pzeferred polyamide material is PebaX M
manufactured by Atochem, Paris, France, which is a polyether block amide thermoplasta,c elastomer. Properties of representative Pebax polymers are pzovided in the following table:
CaRADES

PROPERTY ASTM Ui~TZTS

Specific D-792 gm/cc 1.01 1.01 1.01 Gravity Hardness D-2240 Shore D 55 40 3S

Tensile D-638 MPa 44 36 34 Strength Elongation D-638 % 455 48S ?10 @ Break Another example of a preeferred polymer is SurlynTM
manufactured by E.I. DuPont de Nernours and Company. 9urlyn is an ionically crosslinked thermoplastic polymer (ionome=) '.
WO 9o!24896 PCT/L)S9al04873 of ethylene and methacrylic acid copolymers which exhibit good tear strength, low density, and good flex life. ::
Properties of Surlyn ionomers are provided in the following table: . .
S
GRA DES -PROPERTY ASTM UNITS

Specific D-792 gm/cc 0.96 0.94 Gravity Hardness b-2240 Shore D 55 54 Tensile D-638 MPa 26.2 21.4 Strength -Elongation D,638 % 510 500 ~

Break . . .

As stated, the description of properties of specific polymers is for the purpose of illustrating the types of 2o polymers having desirable properties for use in the sole components of the present invention_ Many other polymers with similar properties are suitable for use in the present invention. Moreover, the data provided is based on available information and cannot be used for direct comparisons among polymers or for guzding precise design .specifications. For example, ASTM testing permits alternative methods for developing property data. In addition, other ingredients added to polymers, such as fillers, reinforcing agents, colorants, etc., can cause variations in properties.
A pz~eferred method of constructing the sole component of the present invention is to mold sheets of a flexible high polymer plastic resin to form upper arid lower sole component halves and then joining the halves to complete the sole component. Preferred materials, as stated, are sheets of flexible thermoplastic resins which can be heated __ ~ ~1~~4~3 ..
WO 94IZ4896 PCTlUS9d)pd8~3 -23- , -and molded into desired sole component shapes. An example of a particularly preferred thermoplastic sheet material is ~~94 Shore A thermoplast~.c polyurethane sheet such as is available from Argoteqh, I~c., Greenfield, Massachusetts. w Sheets are generally about 0.010 inches thick. The thickness of the sheet is selected according to design criteria, but will generally range from about 0.040 to ' about 0.100 inches depending on the particular material properties. For example, particularly preferred thicknesaes for 94 Shore A thermoplastic polyuzethane ranges from about 0.060 inches to about 0.080 inches.
In one embodiment of the present invention, a sheet of a first flexible thermoformable material is heated to its 15~ forming temperature and then molded in a corresponding first mold configured to form from the matezial an upper -' sole half having a top foot-platform member. A sheet of a second flexible thermofosrrtable material is heated tv its -forming temperature and molded in a corresponding second mold configured to form from the material a lower sole component half having a bottom sole component member. The molds are further configured to provide indentations in one oz both of the top and bottom members formed from corresponding protrusions in one oz' both of the molds. For example, Figs. 3-S show molded but unjoined sole component halves wherein the upper sole component half ~0 and lower _ sole component half 41 mirror the respective upper and lower molds having a plurality of indentation forming protrusions_ Once molded, the upper and lower sole 3o component halves are cooled sufficiently for removal from the mold and ate then joined together such as by gluing, fusing, welding, coupling with separate coupling members such as rivets and the like, or by other suitable attachment means.

WO 941Z4896 PCTIIJS94IOa873 One advantage of the construction method of the present invention is the ability to use twQ different materials having different properties to create a variety ~ .' functional values not possible with one material. For example, the sole component can be constructed of materials ' having different thicknesses. Moreover, the shapes used to create function in the sole component can all be connected during the molding process. This is highly advantageous when constructing a sole Component having adequate to cushioning and stability, without adding additional costly operations. For example, a particularly preferred method of constructing the sole component of the present invention __ is through the use of specially designed twin-sheet thermoforming molds and techniques.
Thermoforming in general is a process of shaping thermoplastic resin by heating a sheet or film of the .
plastic resin to a temperature sufficient to make the resin pliable enough to be shaped into a desired form_ Generally, the material is heated uniformly throughout to its normal forming temperature. The normal forming temperature is determined by heating the material to the highest temperature at which it still has enough hot strength to be handled, yet is below the degrading z5 temperature of the material. Preferably, zhe material will have a hot tensile strength adequate to allow the material to stretch uniformly onto and around the mold. The material at its forming temperature is then clamped at its edges and forced into a one-sided mold, typically a .
3o temperature-controlled aluminum mold, by applying a vacuum to the mold side of the material to force the material into the mold. Positive air pressure is also typically applied to the material surface opposite the mold side of the material to assist in foz~cing the material firmly into the 35 mold. When the sheet material is at its forming .
temperature, the material is essentially annealed (stress- ,, ~162~~3 WO 9dtZd896 ~ ' PCTIUS94Ip4873 -ZS-relieved). To avoid forming in stress, the hot sheet y should be forced against the mold as rapidly as possible by application of the vacuum and air pressure. once molded, the part is Cooled to its. set temperature which is the temperature at which the part hardens sufficiently to permit removal of the part from the mold without deforming the molded part. The molded part is then trimmed of excess material, which is generally present at the edges of the molded article where it has been clamped. The excess to material can be recycled if desired.
Twin~sheet thermoforming in particular uses two sheets of material heated to their forming,temperatures, the upper :' sheet forced up into an upper mold half and a lower sheet . forced down into a corresponding lower mold half_ The two ...
mold halves are pressed together and the pressure of the two molds squeezing the sheets together at their forming temperature effectively welds the two materials together at their points of contact_ As illustrated in Figs. 3-7, the points of contact can be along the periphery of the upper and lower. sole component halves and between indentations .' and corresponding portions of the opposite member. In addition, points of contact can be between corresponding indentations. As indicated, air pressuze can be applied between the sheets to assist in forcing the material firmly into the molds. Particularly preferred materials for twin-sheet thermoforming should exhibit good specific heat, i.e., the hot sheet z~etains its temperature for a sufficient time iri the process to easily join surfaces at '.
their contact points. Thermoplastic polyurethane, for example, exhibits good specific heat.
The present invention's process of thermoforming the SNOB Sole component is 7_llustrated generally by referancc to Fig. 11. Referring to Fig. 11, two rolls of thermoplastic sheet stock 30 and 31 are fed from rolls 32 WO 94/21896 - ~ I PCT/US94/Od873 and 33 over rollers 34 to sheet stock heaters 35 to raise the temperature of the sheet stock to substantially its normal, forming temperature. The sheet stock is then advanced to the form station 36 having an upper sole component mold 37 and a lower sole component mold 38. The ' mold halves are closed together and the vacuum is applied to the mold halves to force the upper sheet material into the upper mold 37, and the lower sheet material into the corresponding lower mold 38. Air pxessure can also be applied between the sheets to assist in forcing the materials firmly into the molds. The mold halves remain closed together for a time sufficient to weld the upper and lower materials together at their points of contact. For -.
94 Shore A thermoplastic polyurethane of 0.060 to 0.080 . inches think, for example, the sheets are molded at about 400~F and a cycle time of about 20 seconds. The mold halves are then retracted and the formed sole 39 is removed from the mold after sufficient cooling and advanced further -y down the line for trimming.
Thermoforming has many advantages over other types of molding, including blow molding, when it comes to producing a sole component that is capable of delivering adequate function. Thermoformed soles have tight tolerances as compared to other foam or partial-foam soles_ Cushioning, flexibility, stability, etc. are more predictable with the matezials used in thermoforming and thus makes more feasible the application of foot dynamics research to shoe design. Moreover, as illustrated, the thez~moformed 34 material can be curved or bent at various angles to provide a variety of indented shapes to create regions of selected resistance in the sole to the pressures exerted by the foot and by ground contact. Therefore the invention lends itself to a variety of alternative embodiments as dictated by design considerations. For example, the shapes can be WO 941?.4896 . _ copal-shaped, such as tonal-shaped "pins," z~idges, cubes, platforms, ribs and the like.
As described, tie upper and lower sole component halves can be constructed of different thermoplastic materials. Accordingly, a number of advantages can be engineered into the sole. For example, the top member can be composed of a thicker, heavier thermoplastic material, while the bottom member is composed of a thinner, lighter thermoplastic material. Similarly, having corresponding ,' suppozt members of two different materials increases the ability of the designer to construct differing degrees of flexibility or resistance into specific areas of the sole component. gy varying the materials employed in terms of 15~ specific properties such as tensile strength, material thickness and elongation and by varying indentation .'.
configurations to form support members, a number of consistently reproducible regions of desiz~ed resistance and flexibility can be engineered into the sole to meet 2o specific requirements. For example, in pin/pin arrangements, a thicker, more rigid material can be employed as the top member and a thinner, more flexible material can be employed as the bottom member. The upper pin portion extending from the top member from a stiffer 25 material, would form a more rigid upper pin portion. The lower pin member extending from the bottom sole member would provide a more flexible, "softer" lower support member_ Consequently, cooperating support members are provided having dual characteristics enabling the 3o functional response of the support members to be more .:
precisely engineered. In addition, where the Component .
includes a wall member, the wall member can be formed from two materials, i.e., the wall can be split between the' upper and lower sole component halves_ WO 94!1,4896 ~ .
PCT/US94/048~3 Thermoforming also offers additional advantages.
Thermoforming is efficient and cost effective. Blow molding, for example, requires numerous mold changes to make all the various sizes of.right and left soles. Such .
S mold changes are not economically desirable. Thermoforming .
should permit a sole unit per mold time advantage of at least 5 to to times. In addition, blow molding can use only 1 - 4 molds per cycle. The entire sole size range of approximately 36 molds can be thermoformed in one cycle.
to In addition, the thermoforming process can ut~.lize laminate or printed graphics attached to the plastic sheeting before forming. This permits high precision graphics and unlimited color use. Four-color photo processes could be used for example. Molds can also be configured to add 15~ texture to the component material. Moreover, the thermoforming process does not stretch the hot plastic nearly as much as blow molding. Lim~.ting stretching is vital to keeping graphics acceptable. Stretching also affects the consistency of the material's thickness, which 2o in turn affects the consistency of the sole component's function.
The present invention also lends itself to a number of alternative design considerations. The interval can 25 contain foam, such ae traditional EVA foam, as consumer or user demands might dictate. One or more recesses such as circular shaped indentations or channels can be molded into the sole component td provide receptacles'for cooperating with locking members protruding from outsole materials to 30 attach an outsole to the bottom member of the sole component. In addition, an outsole can be attached to the sole component during the molding process . Th~.s is further illustrated by reference to F~.ge. 12-15. Fig. Z2 shows a partial cutaway view of a lower sale component mold half 24 35 in accordance with one embodiment of the present invention wherein outsole member recesses 25 are designed into the _ ~.~20~3 WO 94/Z4896 PCT/U59410a873 mold. Prior to molding the lower sole half, outsole material a6, such as synthetic rubber material, is positioned in the corresponding recesses Z5. The material 27 for the lower sold component half is molded around protrusions 26a extending from the outsole material thereby lucking the outsole material into the sole component as illustrated in Fig. 13 showing indentations 28 in locking cooperation with the outsole material 26. Referring to .
Figa. 14-15, vacuum ports 29 in the recesses cooperate with ' to channels in the outsole material which permits communication between the vacuum ports and the interior of the mold to permit the applied vacuum pressure to pull the .
hot sole component material around the protrusions of the ' outsole material. Fig. 15 illustzates an alternative ~ embodiment wherein a plurality of protrusions extend from an vutsole member recessed in the mold. An adhesive can be applied to the outsole material prior to molding to ensure adequate bonding between the sole component and the outsole material. The indentations housing the outsole material 2o can also function as support members. In a preferred embodiment, the outsol.e would cover indentations in the bottom member to prohibit dirt and other foreign material from becoming lodged in the indentations.
Z5 The sole of the present invention can be attached to an upper in a variety of ways as well. One traditional method is simply to cement the sole to the upper.
Thermoforming, however, lends itself to particularly advantageous means for attaching the sole component to an 3o upper. For example, cementless attachment mechanisms include a series of one-way snaps which fit into ..
receptacles in either the shoe upper or the sole to lock the shoe upper to the sole. Preferably, Che top member of the sole would be thermoformed with receptacles areund eha 35 periphery of the upper suzface of the sole member's top and designed to accept corzesponding one-way snaps extending _ ~. _ ~ ~.~~a~~
WO 94i?A~896 PCTIIJS94104$73 outwardly from the periphery of the bottom of the shoe upper. Referring to Figs. 16-18, the upper surface of the top member of the sole 5D zn accordance with the present invention is shown wherein, snap receptacles S1 are positioned along the peziphery or outside edge of the upper surface of the sole. The lower surface of the shoe upper 52 includes outwardly extending one-way snaps 53 positioned along the periphery of the lower Surface of the shoe upper to coxrespand to the location of the receptacles in the to sole. Figa. I9-21 illustrate an alternative embodiment wherein a locking channel 54 is molded into the upper surface of the top member o~ the sole 50 along its periphery and a corresponding lipped rib member 5S extends downward from the lower surface of the shoe upper 52. The ~ lip is engaged in the locking channel to attach 4he shoe upper to the sole.
A second preferred embodiment is shown in Figs. 2Z-25.
In the second preferred embodiment, one or more of the 2o inwardly directed indentations in the top and bottom members have a hemispherical shape. Ae shown in Fig. 22, top platform member 106 is joined to bottom member 1o7 and preferably the members are joined at their outer periphery 108. Extending into the interval between the top and bottom members aze a plurality of inwardly cirected indentations 109 to provided internal support to the shoe sole component structure. As indicated above, one or more of indentations 1o9 are hemisphere-shaped. In the second preferred embodiment, the diameter of each hemisphere- .-3o shaped indentation may be anywhere from approximately 1/8"
to 1/2". The hemisphere-shaped indentations in the cop and bottom members may be abutting and/or may be joined together using adhesive or other mea»s.
The hemisphere-shaped indentations in the Lop and bottom members preferably are formed from sheets of .

WO 94l?A896 ~' ~ ~ ~ ~ ~ J Iv PC~'/US94/04873 ~31-flexible high polymer plastic resin which can be heated and molded into these sole components. The hemisphere-shaped .
indentations are integral. portions of each sole component to provide a controlled collapsing of the material and thereby create areas of cushioning and stability as desired in the shoe sole.
A significant advantage of the hemisphere shape for the indentations in the shoe sole structure is improved to fatigue resistance oven the life of the sole. The hemisphere has better resistance to cracking when subject to compression than other shaped indentations. Other advantages of hemisphere-shaped indentations include better performance across the entire force deformation cycle for 15. comfort and injury prevention, and reduction in stress and strain in the material used for the top and bottom sole portions_ The hemisphere shape has the advantage of a smooth 20 load definition curve, increasing the perceived comfort of _ the cushioning system. Additionally, the hemispherieal-shape minimizes the induced stresses and strains in the material from which the indentation is made. Consequently, indentations using the design of the hemisphere~are more 25 durable than cushioning members of other designs made from the same material. The stress distribution of hemisphere-shaped indentations enhances the life of the cushioning members and controls cushioning and comfort, without the need to insert foam or other filler between the top and .-3~ bottom members, or to inject air or some other gas or fluid into the ~.nterval between the top and bottom members.
As shown in Fig. 22, the hemisphere-shaped indentations may be combined with ocher indentations in the 35 top and bottom members to provide cushioning characteristics as needed for different aet~.vities. For WO 9dl?.d896 ' . PCT/CTS94/04873 -32~
example, the forefoot may use hemisphere shapes as well as ' ribs to provide cushioning characteristics different than the heel portion of the shoe sole.
Alao shown in Fig. Z2 is passageway 120 which extends ' through top member 106, which provides a passageway for air to communicate from the inside to the outside of the top and bottom components. Thus, the internal cavity between w the top and bottom sole components does not entrap air, but allows air to escape the interval during compression so as Co not interfere with cushioning. Additional air passageways may be used in both the top and bottom members as desired to provide additional air blow_ ~ The heel portion of the sole structure of Fig. 22 preferably includes a top platform member and bottom platform member, each havzng a plurality of inwardly .
directed indentations 109 that are hemispherical in shape.
Preferably, the heel portion includes five or more indentations in a generally cizcular pattern, or donut-shaped configuration.
Now referring to Fig. 24, one or more indentations 109 in bottom member 107 are adapted to receive inserts il~
therein. For example, as shown in Fig. 24, each of the inserts may be a hemisphere-shaped rubber plug 117 that fits into each of the hemisphere-shaped indentations ~.n the bottom member. Prefez~ably, the hemisphere-shaped rubber plug is hollow. Similarly, inserts 118 having a conical 3o shape may be inserCed into other indentations, such as conical-shaped indentations in the bottom member 1o7.
Now referrring to Fig. 25, zriserts 117 provide an abzasion resistant, fractional surface for contact with the ground. If desired, each insert 117 may extend slightly from its corresponding indentation. Additionally, the WO 94!2d$96 ~ ' ' ~ , .
PCTlUS94104873 inserts may be used to adjust the cushioning characteristics of the shoe sole component.
Alternatively, the,hemispherical shaped inserts may be attached together using the web-like structures 110, 112 shown in Fig. 23. The web-like structure provides a trampoline-like effect undex the heel portion of the shoe.
The web-like structure may be formed of the same plastic of the top or bottom members, ox' a material softer than the sole if desired.
In a preferred embodiment, the inserts are attached to indentations in the top and bottom members using the following method. Preferably, the inserts are made of rubber. Fi.rat, the inserts are conditioned by sandblasting ._ or othez techniques to prepare the outer surface of the rubber. Then, a primer and an adhesive are applied to the rubber surface which will be in contact with the indentation. Preferably, the primer is a chlorine based __ 2D primer and the adhesive is a urethane based heaC-activated adhesive. Next, the inserts are placed in a mold having cut-out areas configured for the shape of the insert. The twin sheets of thermoplastic are heated to a desired :.
temperature (preferably from 350 to 400 degrees) and enter the top and bottom molds, as shown in Fig. 11. As discussed earlier in the specification, the molds preferably include air passages, and a negative or vacuum w pressure is applied to urge the heated thermoplastic :-against the mold to conform the thermoplastic to the shape of the various indentations therein. Then, a needle is inserted through one or more air passages 120 in the cop or bottom members and positive air pressure is provided to urge the indentation in the top or bottom member against ..
the insert_ This provides a method of securing the inserts into each of the indentations.

- '' WO 9417~d896 pCTlUS94/048~3 -34- ..
As discussed above, the shoe sole component of the '' present invention does not require a separate outsole attached to the bottom member, although a separate outsole may be used if desired. , In the second preferred embodiment, no conventional outsole is used. Instead, as ' shown in Figs. 24-25, inserts 117, 118 adapted to be inserted in indentations in the bottom member serve the functions of a conventional outsole, including traction and abrasion resistance. The inserts shown in Figs. 24 and 25 l0 also have several. advantages over a conventional outsole, including (1) less weight than a conventional outsole; (2) replaceability of each individual insert; (3) arrangement .
of each insert for selected cushioning and/or wear , characteristics.
Inserts 117, 118 preferably are made of rubber such as SBR rubber and may have hardness anywhere from approximately 35 to 95 on the Shore A scale. In a preferred embodiment the inserts axe hollow rubber plugs.
Preferably, each insert has a hollow cavity therein.
However, the inserts may be solid rubber plugs or, if =
desired, may have other internal structure for specific w applications. As stated above, the inserts may be shaped to fit into various different indentations in the sole structure including hemispherical, conical, or other shaped indentations. The inserts may be attached to each indentation by adhesive. Or, as discussed above, during thermoforming of the sole, the inserts may be attached to each indentation_ The indentations and inserts can be adapted to make one part of the shoe sole stiffer in compression than the other part of the shoe sole. For example, a difference in .
stiffness for compression on the medial side i14 and lateral side 115 can be achieved. Or, a difference in stiffnes for compz~ession on the forefoot and heel of the . ' _ .. .~.~~0~~
WO 9d/TA896 ~ ' ~ PCTIUS94/04873 shoe can be achieved. Theze are a number of different ways to provide this difference in compression. A smaller hemisphere radius may be used for the indentations on one side of the shoe sole.. Inserts made of a material with a higher modulus of elasticity may be used in the indentations on one side of the shoe sole_ Alternatively, inserts with greater wall thickness may be used for the indentations on one side of the shoe sole. These w variations may be used to provide effective pronation l0 control through differences in compression between the medial and lateral sides of the shoe sole. Additionally, inserts may be added around the periphery of the shoe sale structure if desired.
is ~ Preferably, the forefoot of the sole structure includes indentations 121 and bars 122 which extend across the top and bottom members from the lateral side to the medial side. The' indentations 121 and bars 122 do not entrap air, but allow air to communicate with the interval 20 between the top and bottom members, and to escape through passageway 120 to provide the desired cushioning characteristics. w The foregoing description is fvr the purpose of 25 illustrating the invention. Many othez variations will be apparent to those of ordinax-y skill in the art and all such ..
variations are encompassed within the scope of the present invention. '

Claims (39)

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A shoe sole structure, comprising:
(a) a flexible sole-shaped top sheet of thermoplastic and having a plurality of indentations therein;
(b) a flexible sole-shaped bottom sheet of thermoplastic and having a plurality of indentations therein, the bottom sheet joined at its periphery to the top sheet to form a cavity therebetween;
(c) the indentations in the top sheet having sufficient depth to form projections extending inwardly into the cavity to abut indentations in the bottom sheet to retain the top member and bottom member in spaced relationship, each indentation forming a recess facing outwardly, at least one of the indentations in the top sheet or bottom sheet being hemispherical in shape.

2. The shoe sole structure of claim 1 wherein the indentations are resiliently deformable to provide cushioning.

3. The shoe sole structure of claim 1 wherein a plurality of indentations in the top sheet are attached to indentations in the bottom sheet.

4. The shoe sole structure of claim 1 wherein at least one of the top and bottom members includes a passageway between the cavity and ambient air.

5. The shoe sole structure of claim 1 further comprising at least one hemisphere-shaped plug insertable into one of the indentations in the bottom member or top member.

6. A shock absorbing apparatus, comprising:
(a) a first flexible high polymer resin sheet having an outer periphery and a plurality of hemispherical shaped indentations therein; and (b) a second flexible high polymer resin sheet coextensive with and attached to the first sheet and having an outer periphery and a plurality of hemispherical shaped indentations therein;
(c) at least one hemispherical shaped insert configured for insertion into a hemispherical shaped indentation in the second sheet; and (d) a cavity between the first sheet and second sheet the cavity coextensive with the first and second sheets, each of the plurality of hemispherical shaped indentations in the first and second sheets having sufficient depth to project inwardly into the cavity and having a recess facing outwardly.

7. The shock absorbing apparatus of claim 6 wherein at least one of the indentations in the first sheet is aligned with and abuts an indentation in the second sheet, the indentations being resiliently deformable upon application of force thereto.

8. The shock absorbing apparatus of claim 6 wherein at least one of the indentations in the first sheet is joined to an indentation in the second sheet.

9. The shock absorbing apparatus of claim 6 wherein the first sheet and second sheet are joined at the outer periphery of said sheets.

10. A shoe sole component configured for incorporation into a shoe sole comprising:
(a) a top member formed of a flexible high polymer resin sheet;
(b) a bottom member formed of a flexible high polymer resin sheet and being in at least partially coextensive relationship to said top member, said top and bottom members opposing one another and being in at least partially spaced relation to one another to define an interval therebetween;
(c) a plurality of support members comprising inwardly directed indentations in the top member and opposing inwardly directed indentations in the bottom member, said indentations in each of said top and bottom members being integral with each of said members respectively and having sufficient depth to form a projection configured to extend into said interval and an outwardly facing recess, at least one of said inwardly directed indentations in each of said top and bottom members having a hollow hemispherical shape;
(d) at least one insert having a hemispherical shape insertable into the recess of an inwardly directed indentation in the bottom member.

11. The shoe sole component of claim 10 wherein each inwardly directed indentation having a hollow hemispherical shape in the top member abuts a corresponding inwardly directed indentation having a hollow hemispherical shape in the bottom member.

12. The shoe sole component of claim 10 wherein at least one inwardly directed indentation having a hollow hemispherical shape in the top member is joined to an inwardly directed indentation having a hollow hemispherical shape in the bottom member.

13. The shoe sole component of claim 10 wherein at least one of the inwardly directed indentations having a hollow hemispherical shape in one member is more resistant to compression than the inwardly directed indentation having a hollow hemispherical shape in the opposing member.

14. The shoe sole component of claim 10 wherein at least one of the inwardly directed indentations having a hollow hemispherical shape in one member has a greater radius than the inwardly directed indentation in the opposing member.

15. The shoe sole component of claim 10 wherein at least one of the inserts has a greater resistance to compression than another insert.

16. The shoe sole component of claim 10 wherein at least one of the inserts has a greater hardness than another insert.

17. The shoe sole component of claim 10 wherein at least one of the inserts has a greater radial thickness than another insert.

18. The shoe sole component of claim 10 wherein at least one of the inserts has a greater radius than another insert.

19. The shoe sole component of claim 10 wherein the shoe sole component comprises a medial side and a lateral side, the inwardly directed indentations on the medial side of the shoe sole component are more resistant to compression than the inwardly directed indentations on the lateral side of the shoe.

20. The shoe sole component of claim 10 wherein the shoe sole component comprises a medial side and a lateral side, the inwardly directed indentations on the lateral side of the shoe sole component are more resistant to compression than the inwardly directed indentations on the medial side of the shoe.

21. The shoe sole component of claim 10 wherein the shoe sole component comprises a forefoot and a heel portion, the inwardly directed indentations in the forefoot of the shoe sole component are more resistant to compression than the inwardly directed indentations in the heel of the shoe.

22. The shoe sole component of claim 10 wherein the shoe sale component comprises a forefoot and a heel portion, the inwardly directed indentations in the heel of the shoe sole component are more resistant to compression than the inwardly directed indentations in the forefoot of the shoe.

23. The shoe sole component of claim 10 wherein the shoe sole component comprises a heel portion, the inwardly directed indentations each having a hollow hemispherical shape are arranged in a generally circular pattern in the heel portion of the shoe sole component.

24. A shoe sole structure, comprising:
(a) a flexible top sheet having a plurality of indentations therein, each indentation including a recess on one surface of the sheet and a projection on the opposite surface of the sheet;
(b) a flexible bottom sheet in parallel spaced relation with the top sheet and having an outer periphery and a plurality of indentations therein, each indentation including a recess on one surface of the sheet and a projection on the opposite surface of the sheet;
(c) the projections of the indentations in the top sheet abutting the projections in the indentations in the bottom sheet;
(d) a plurality of inserts insertable into the recesses of the indentations in one of the sheets; and (e) a webbed structure linking the plurality of inserts together.

25. The shoe sole structure of claim 24 wherein at least one of the indentations is hemispherical in shape and at least one of the inserts is hemispherical in shape the outer surface of the hemispherical shaped insert conforming to the recess of the hemispherical shaped indentation.

26. The shoe sole structure of claim 25 wherein the hemispherical shaped indentations are in the top sheet.

27. The shoe sole structure of china 26 wherein the shoe sole structure comprises a shoe heel portion and the hemispherical shaped indentations are in the shoe heel portion of the top sheet.

28. The shoe sole structure of claim 25 wherein the hemispherical shaped indentations are positioned in a generally circular pattern.

29. The shoe sole structure of claim 28 wherein the plurality of inserts insertable into the recesses of the indentations are in a generally circular pattern and are attached to the webbed structure linking the inserts.

30. The shoe sole structure of claim 25 wherein the hemispherical shaped indentations are in the bottom sheet.

31. The shoe sole structure of claim 30 wherein the shoe sole structure comprises a shoe heel portion and the hemispherical shaped indentations are in the shoe heel portion of the bottom sheet.

32. The shoe sole structure of claim 24 wherein the top sheet and bottom sheet each have a plurality of hemispherical shaped indentations.

33. A shoe sole structure comprising:
(a) a flexible top sheet having a plurality of indentations therein;
(b) a flexible bottom sheet having a plurality of indentations therein, the indentations in the bottom sheet abutting the indentations in the top sheet;
(c) a plurality of the indentations in one of the sheets having a hemispherical shape;
(d) a plurality of hemispherical shaped inserts insertable into the hemispherical shaped indentations and conforming to the surface of the indentations; and (e) a web-like structure linking the inserts to each other.

34. The shoe sole structure of claim 33 further comprising means for joining at least a portion of the top sheet with the bottom sheet and a cavity between the top sheet and bottom sheet.

35. The shoe sole structure of claim 33 wherein the top sheet and bottom sheet each have an outer periphery and the top sheet is joined to the bottom sheet at the outer periphery of each sheet.

36. The shoe sole structure of claim 33 wherein the plurality of hemispherical shaped indentations are arranged in a generally circular pattern and the inserts are arranged in a generally circular pattern and are attached to the web-like structure.

37. The shoe sole structure of claim 33 wherein the plurality of hemispherical shaped indentations are in the top sheet.

38. The shoe sole structure of claim 33 wherein the plurality of hemispherical shaped indentations are in the bottom sheet.

39. The shoe sole structure of claim 33 wherein the plurality of hemispherical shaped indentations are in the top sheet and the bottom sheet.