This disclosure relates to shoes.
Generally, shoes include an upper portion and a sole. When the upper portion is secured to the sole, the upper portion along with the sole define a void that is configured to securely and comfortably hold a human foot. Often, the upper portion and/or sole are/is formed from multiple layers that can be stitched or adhesively bonded together. For example, the upper portion can be made of a combination of leather and fabric, or foam and fabric, and the sole can be formed from at least one layer of natural rubber. Often materials are chosen for functional reasons, e.g., water-resistance, durability, abrasion-resistance, and breathability, while shape, texture, and color are used to promote the aesthetic qualities of the shoe.
Generally, the disclosure relates to shoes having variable flexibility, e.g., laterally, or along a longitudinal axis of the shoe. For example, shoes are disclosed that have arm portions and/or plates having variable flexibility.
In one aspect, the disclosure features shoes having an assembly including a foot support structure and a plate mounted upon the foot support structure. The foot support structure includes a cross member, and a first pair of cantilevered arm portions extending from the cross member in a heelward direction, with a first, heelward-extending gap defined therebetween. If desired, the first pair of cantilevered arm portions can be, e.g., configured to reengage in a heelward direction, spaced from the cross member. In some configurations, the cross member can be, e.g., disposed in a forefoot region of the foot support structure.
In some implementations, the foot support structure includes a second pair of cantilevered arm portions extending from the cross member in a toeward direction, with a second, toeward-extending gap defined therebetween. If desired, the second pair of cantilevered arm portions can be, e.g., configured to reengage in a toeward direction, spaced from the cross member.
In some implementations, the foot support structure defines a first, upper surface directed towards a wearer's foot when the shoe is worn and an opposite surface. The plate can be, e.g., mounted upon the first surface.
The plate can, e.g., vary in beam stiffness along a longitudinal axis of the shoe. In such instances, the beam stiffness is measured as a product of an overall moment of inertia of a nominal cross-section and an effective modulus of elasticity (Young's modulus) of a material from which the plate is formed.
The plate can, e.g., vary in thickness along a longitudinal axis of the shoe and/or can be formed from materials that vary in hardness and/or flexural modulus.
In some implementations, the plate is formed from polymeric material, e.g., a thermoplastic (e.g., a thermoplastic polyurethane). The polymeric material can have, e.g., a flexural modulus of from about 5.0 MPa to about 2000 MPa, measured at 25° C. by DMA in a linear region of a stress strain curve. In specific implementations, the polymeric material has a flexural modulus that is from about 15.0 MPa to about 1200 MPa. In some implementations, the polymeric material has a hardness of from about 50 Shore A to about 80 Shore D, as measured using ASTM D2240 at 25° C. In specific implementations, the hardness is from about 70 Shore A to about 76 Shore D.
In some implementations, the plate has a toeward portion and a heelward portion, and the heelward portion has a relatively higher beam stiffness than the toeward portion. In specific implementations, the toeward portion and the heelward portion are each formed from a polyurethane material, e.g., a thermoplastic polyurethane. Each portion can be made, e.g., by molding (e.g., co-molding). In specific implementations, the material from which the toeward portion of the plate is made has a hardness of from about 50 Shore A to about 95 Shore A and a flexural modulus of from about 5.0 MPa to about 105.0 MPa; and the material from which the rearward portion of the plate is made has a hardness of about 90 Shore A to about 76 Shore D and a flexural modulus of from about 75.0 MPa to about 1700 MPa. In some implementations, a thickness of the toeward and/or heelward portion of the plate is from about 0.25 mm to about 2.5 mm.
In some implementations, the first, heelward-extending gap defined between the first pair of cantilevered arm portions extends along at least 50 percent of a total length of the foot support structure, e.g., at least 60 percent, 65 percent, 70 percent, 75 percent, or at least 85 percent of the total length of the foot support structure.
The foot support structure can made, e.g., from a material that includes a polyolefin, e.g., ethylene-vinyl-acetate copolymer (EVA) or linear, low density polyethylene (e.g., a copolymer of ethylene and a 5-20 carbon α-olefin such as 1-octene). The foot support structure can be made, e.g., by injection molding or compression molding. The material of the foot support structure can be foamed during the forming of the foot support structure, making it, e.g., advantageously low in density, and, therefore, weight. When the material of the foot support structure is foamed, the cellular structure of the foam can be open or closed. In implementations in which the material of the foot support structure is foamed, it can, e.g., have a hardness from about 30 ASKER C to about 75 ASKER C, e.g., 40 ASKER C to about 60 ASKER C, as measured using Japanese Standard SRIS 0101 at 25° C.
In implementations in which the support structure includes a second pair of cantilevered arm portions extending from the cross member in a toeward direction, with a second, toeward-extending gap defined therebetween, a combined length of the first gap and the second gap can be, e.g., at least 50 percent of a total length of the foot support structure, e.g., at least 60 percent, 65 percent, 70 percent, 75 percent, 85 percent, or at least about 90 percent of a total length of the foot support structure.
In some implementations, the assembly is used in a sandal or a boating shoe.
In some implementations, the foot support structure also includes straps, e.g., that extend through reinforced apertures defined in the foot support structure. If desired, straps can be made releasably engageable, e.g., by applying hook-and-loop type fasteners to the straps.
If desirable, the shoe assembly can further include a liner mounted to an outer surface of the plate. This can be advantageous, e.g., for additional shock-absorbing, when desired. The liner material can, e.g., define siping extending transversely to a longitudinal axis of the shoe. This can be advantageous when extra traction and slip resistance is desired. In specific implementations, the liner is formed from foamed EVA. When the liner is formed from foamed material, it can have, e.g., a hardness from about 25 ASKER C to about 65 ASKER C, e.g., 35 ASKER C to about 55 ASKER C, as measured using Japanese Standard SRIS 010 at 25° C. When the material of the liner is foamed, the cellular structure of the foam can be open or closed.
In some implementations, the shoe assembly further includes an outsole mounted to the opposite surface of the foot support structure. Such an outsole can, e.g., increase the wear-resistance of the shoe assembly. The outsole can define siping extending transversely to a longitudinal axis of the shoe. In specific implementations, the outsole is formed from vulcanized rubber material, e.g., a natural rubber material. In some implementations, the outsole is formed from a material having a hardness from about 40 Shore A to about 95 Shore A, e.g., from about 50 Shore A to about 80 Shore A, as measured using ASTM D2240 at 25° C.
In another aspect, the disclosure features shoes having an assembly having a foot support structure and a top plate mounted upon the foot support structure. The foot support structure includes a cross member, and a first pair of cantilevered arm portions extending from the cross member in a toeward direction, with a first, toeward-extending gap defined therebetween. If desired, the first pair of cantilevered arm portions can, e.g., be configured to reengage in a toeward direction, spaced from the cross member. In some configurations, the cross member can be, e.g., disposed in a forefoot region of the foot support structure. Any of the features described above with respect to the first aspect can be applied to this aspect.
In another aspect, the disclosure features a shoe that includes a plate formed of at least two different materials. For example, the plate can have a toeward portion and a heelward portion. In such implementations, the heelward portion can, e.g., have a relatively higher beam stiffness than the toeward portion. In specific implementations, the toeward portion includes a polymeric material having a hardness of from about 50 Shore A to about 95 Shore A and a flexural modulus of from about 5.0 MPa to about 115.0 MPa; and the rearward portion includes a polymeric material having a hardness of about 85 Shore A to about 80 Shore D and a flexural modulus of from about 75.0 MPa to about 1900 Mpa.
In another aspect, the disclosure features shoes having a foot support structure that includes a cross member, and a first pair of cantilevered arm portions extending from the cross member in a heelward direction, with a first, heelward-extending gap defined therebetween. If desired, the first pair of cantilevered arm portions can be, e.g., configured to reengage in a heelward direction, spaced from the cross member. In some configurations, the cross member can be, e.g., disposed in a forefoot region of the foot support structure. In some implementations, the foot support structure includes a second pair of cantilevered arm portions extending from the cross member in a toeward direction, with a second, toeward-extending gap defined therebetween. If desired, the second pair of cantilevered arm portions can be, e.g., configured to reengage in a toeward direction, spaced from the cross member. Any of the other features described herein with respect to the foot support structure can be applied to this aspect.
Implementations may include any one, or combination of the following advantages. The shoes described herein flex naturally along with the wearer's feet, allowing the wearer to control his/her movement as if they were barefoot, while at the same time providing adequate protection for the wearer. The shoes are lightweight. The shoes have enhanced breathability, providing many hours of continuous comfort.
The details of one or more implementations are set forth in the accompanying drawings and the description below. Other features, and advantages of the disclosure will be apparent from the description and drawings, and from the claims.
Referring to
In some implementations, top plate 30 varies in beam stiffness along a longitudinal axis (indicated by double-headed arrow 90) of the shoe. The beam stiffness is measured as a product of an overall moment of inertia of a nominal cross-section and an effective modulus of elasticity (Young's modulus) of a material from which the plate is formed. Beam stiffness can be varied by varying material hardness and/or flexural modulus and/or thickness of the plate 30.
In some implementations, top plate 30 is formed of polymeric material, e.g., thermoplastic or thermoset polymeric material. The thermoplastic material can be, e.g., an elastomer, e.g., natural rubber, blends of styrenic block copolymers and polypropylene, elastomeric nylons (e.g., polyetheramides) or polyurethanes. In specific implementations, the thermoplastic is a polyurethane, e.g., polyether or polyester soft-segment polyurethane, such as those available from Dow Plastics under the tradename PELLETHANE™ AND ISOPLAST™. In some implementations, the polymeric material has flexural modulus of from about 2.5 MPa to about 2100 Mpa, e.g., from about 5.0 MPa to about 500 Mpa, as measured at 25° C. by DMA in a linear region of a stress strain curve. In some implementations, the polymeric material has hardness of from about 50 Shore A to about 85 Shore D, e.g., from about 75 Shore A to about 76 Shore D, as measured using ASTM D2240 at 25° C.
Referring again particularly to
In some implementations, the material of the toeward portion 92 of plate 30 has hardness of from about 80 Shore A to about 95 Shore A, flexural modulus of from about 5.0 MPa to about 85.0 MPa and a thickness from about 0.25 mm to about 2.5 mm; and
the material of the rearward portion 94 of plate 30 has hardness of about 95 Shore A to about 80 Shore D, flexural modulus of from about 75.0 MPa to about 1700 MPa, and a thickness from about 0.25 mm to about 2.5 mm.
In a specific example, the material of the toeward portion 92 of plate 30 has hardness of from about 90 Shore A and a thickness of 1.5 mm; and the material of the rearward portion 94 of plate 30 has hardness of about 74 Shore D and a thickness 1.5 mm.
In some implementations, a combined length of the second, toeward-extending gap 72 and the first, heelward-extending gap 60 is at least 50 percent of a total length L (see
Foot support structure 20, liner 100 and outsole 120 can each independently be formed of thermoset material, e.g., natural rubber, or thermoplastic, e.g., polyolefin material. For example, the thermoplastic material can be an elastomer, e.g., styrenic block copolymer, polyethylene, linear, low density polyethylene (e.g., a copolymer of 1-octene and ethylene), polyurethane (e.g., a polyether or polyester soft-segment polyurethane), elastomeric polyester (e.g., polyether-polyester), and mixtures of these elastomers. In specific implementations, support structure 20 is formed by injection molding using ethylene-vinyl-acetate copolymer (EVA) and a foaming agent, e.g., an exothermic or endothermic foaming agent. Chemical foaming agents are available from Clariant Corporation under the tradename HYDROCEROL®. When the material is foamed, the cellular structure of the foam can be open or closed.
In some implementations, support structure 20 has a maximum thickness, measured from lower surface 82 to upper surface 80, of from about 15.0 mm to about 35.0 mm, e.g., from about 18.0 mm to about 25.0 mm. In specific implementations, the material of support structure 20 is a foam having hardness of from about 30 ASKER C to about 75 ASKER C, e.g., 40 ASKER C to about 60 ASKER C, as measured using Japanese Standard SRIS 0101 at 25° C. In a specific example, the foam has hardness of about 53 ASKER C.
Referring to
Referring to
A number of implementations have been described. Nevertheless, it will be understood that various modifications may be made without departing from the spirit and scope of the disclosure.
While implementations have been shown in which the foot support structure has both heelward and toeward extending cantilevered arm portions, in some implementations, the foot support structure has only heelward or only toeward cantilevered arm portions. For example, referring to
While implementations have been shown in which foot support structures have cantilevered arm portions that do not reengage, in some implementations, the arm portions may reengage. For example,
While implementations have been shown in which cross members are generally disposed in the forefoot of the foot support structure, in other implementations, such cross members may be disposed in other locations, e.g., locations central to the foot support structure.
Accordingly, other implementations are within the scope of the following claims.
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