Patent Publication Number: US-10786040-B2

Title: Multi-durometer sole structure for an article of footwear

Description:
TECHNICAL FIELD 
     The present disclosure relates to a multi-durometer sole structure for an article of footwear. 
     BACKGROUND 
     Footwear typically includes a sole configured to be located under a wearer&#39;s foot to space the foot away from the ground or floor surface. Soles can be designed to provide a desired level of cushioning. The ground contact surface of the article of footwear can be configured for durability 
     SUMMARY 
     During the follow through of a golf swing, a golfer should pronate his back foot more than his front in order to maximize the distance and accuracy of the golf shot. Accordingly, it is desirable to induce foot pronation during the follow through of a golf swing. Training, however, is necessary to induce foot pronation during a golf swing. To this end, the present disclosure describes a multi-durometer sole structure for an article of footwear. In certain embodiments, the multi-durometer sole structure includes a sole structure body including a forefoot region, a heel region, and a midfoot region between the heel region and the forefoot region, a medial edge, and a lateral edge opposite the medial edge. The sole structure body further includes a first body segment extending along the forefoot region, the midfoot region, and the heel region, a second body segment extending along the forefoot region, the midfoot region, and the heel region, and a third body segment extending along the midfoot region and the heel region. The first, second, and third body segments are made of different materials having three different hardnesses, respectively. As such, the total hardness of the sole structure body varies from the medial edge to the lateral edge in order to induce foot pronation during a golf swing. Each of the first body segment and the second body segment defines an inner body surface and an outer body surface opposite the inner body surface, and the inner body surface of the first body segment is flushed with the inner body surface of the second body segment. 
     “A,” “an,” “the,” “at least one,” and “one or more” are used interchangeably to indicate that at least one of the item is present; a plurality of such items may be present unless the context clearly indicates otherwise. All numerical values of parameters (e.g., of quantities or conditions) in this specification, including the appended claims, are to be understood as being modified in all instances by the term “about” whether or not “about” actually appears before the numerical value. “About” indicates that the stated numerical value allows some slight imprecision (with some approach to exactness in the value; approximately or reasonably close to the value; nearly). If the imprecision provided by “about” is not otherwise understood in the art with this ordinary meaning, then “about” as used herein indicates at least variations that may arise from ordinary methods of measuring and using such parameters. In addition, a disclosure of a range is to be understood as specifically disclosing all values and further divided ranges within the range. 
     The terms “comprising,” “including,” and “having” are inclusive and therefore specify the presence of stated features, steps, operations, elements, or components, but do not preclude the presence or addition of one or more other features, steps, operations, elements, or components. Orders of steps, processes, and operations may be altered when possible, and additional or alternative steps may be employed. As used in this specification, the term “or” includes any one and all combinations of the associated listed items. 
     Those having ordinary skill in the art will recognize that terms such as “above,” “below,” “upward,” “downward,” “top,” “bottom,” etc., are used descriptively for the figures, and do not represent limitations on the scope of the present teachings, as defined by the claims. 
     The above features and advantages and other features and advantages of the present teachings are readily apparent from the following detailed description of the best modes for carrying out the teachings when taken in connection with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic top view of a sole structure for an article of footwear. 
         FIG. 2  is a schematic, cross-sectional view of the sole structure shown in  FIG. 1 . 
         FIG. 3  is a plot of the hardness of the sole structure from the medial side to the lateral side. 
     
    
    
     DETAILED DESCRIPTION 
     Referring to the drawings, wherein like reference numbers correspond to like or similar components throughout the several figures,  FIGS. 1 and 2  schematically illustrate a sole structure  12  for an article of footwear  10 . The article of footwear  10  further includes a footwear upper  14  ( FIG. 1 ) secured to the sole structure  12 . As a non-limiting example, the article of footwear  10  may be a golf shoe  11 . The sole structure  12  includes one or more sole structure bodies  15 . For example, one of the sole structure bodies  15  may be an outsole  16  configured to contact the ground. 
     For purposes of reference, the outsole  16  (or any other sole structure body  15 ) extends along a central longitudinal axis X and has a heel region  18 , a midfoot region  20 , and a forefoot region  22 . The midfoot region  20  is disposed between the heel region  18  and the forefoot region  22 . For purposes of discussion, the heel region  18 , the midfoot region  20 , and the forefoot region  22  are defined as the rearmost third, the middle third, and the foremost third of the outsole  16 , respectively. The heel region  18  generally includes regions of the outsole  16  corresponding with rear regions of a human foot including the calcaneus bone and of a size corresponding with the outsole  16  and article of footwear  10 . The forefoot region  22  generally includes regions of the outsole  16  corresponding with the toes and the joints connecting the metatarsals with the phalanges of the human foot of the size corresponding with the outsole  16  and article of footwear  10 . The midfoot region  20  generally includes regions of the outsole  16  corresponding with an arch area of the human foot of the size corresponding with the outsole  16  and article of footwear  10 . Accordingly, the midfoot region  20  is also referred to as the outsole arch region. 
     As used herein, a lateral side of a component for the article of footwear  10 , such as an lateral edge  24  of the outsole  16 , is a side that corresponds with the side of the foot of the wearer of the article of footwear  10  that is generally further from the other foot of the wearer (i.e., the side closer to the fifth toe of the wearer). The fifth toe is commonly referred to as the little toe. A medial side of a component for the article of footwear  10 , such as a medial edge  26  of the outsole  16 , is the side that corresponds with an inside area of the foot of the wearer and is generally closer to the other foot of the wearer (i.e., the side closer to the hallux of the foot of the wearer). The hallux is commonly referred to as the big toe. The lateral edge  24  and the medial edge  26  both extend around the periphery of the outsole  16  from the foremost or forefoot edge  28  to the rearmost or heel edge  30  of the outsole  16 . The outsole  16  can be a single-piece or unitary structure and can be manufactured using an insert molding process. The material for the outsole  16  may be selected to provide a desirable combination of durability and flexibility. For example, the outsole  16  may be wholly or partly made of a thermoplastic, such as a thermoplastic rubber, ethylene vinyl acetate (EVA) or other suitably durable material. As a non-limiting example, the outsole  16  is wholly or partly made of thermoplastic polyurethane (TPU). 
     Aside from the outsole  16 , the sole structure  12  may include other sole structure bodies  15 , such as a midsole  32 . The midsole  32  overlays at least part of the outsole  16 . Specifically, in the depicted embodiment, the midsole  32  is directly secured to the outsole  16  and extends over a majority or all the outsole  16 . The midsole  32  defines an upper midsole surface  19  and a lower midsole surface  21  opposite to the upper midsole surface  19 . The upper midsole surface  19  faces away from the outsole  16 , and the lower midsole surface  21  faces toward the outsole  16 . The midsole  32  is wholly or partly made of a material that combines a desired level of resiliency and support, such as an ethylene vinyl acetate (EVA) foam and polyurethane foam. 
     The sole structure  12  further includes an insole  34  that overlays the midsole  32 . The insole  34  may be alternatively referred to as sock liner and is directly secured to the midsole  32  and extends over a majority of the upper midsole surface  19 . The insole  34  may be made of a cushioning foam material, such as a lighter weight and less rigid foam than the midsole  32 . For instance, the insole  34  may be formed of a deformable (for example, compressible) material, such as polyurethane foams, EVA foams, or other polymer foam materials. As a non-limiting example, the insole  34  may be wholly or partly made of a blend of the EVA and Nitrile rubber. Accordingly, the insole  34  may, by virtue of its compressibility, provide cushioning, and may also conform to the foot in order to provide comfort, support, and stability. The insole  34  has a foot-receiving surface  36  and a midsole-facing surface  38  opposite the foot-receiving surface  36 . 
     The midsole  32  is at least partly disposed between the outsole  16  and the insole  34 . The outsole  16  and the midsole  32  can be secured to one another by thermoforming during a molding process, by thermoplastic layers that melt to bond the components, by adhesives, or by any other suitable manner. The footwear upper  14  is secured in any suitable manner to the sole structure  12 . More specifically, the footwear upper  14  is secured to an inner outsole peripheral surface  51  of the outsole  16 , and to an inner midsole peripheral surface  52  of the midsole  32 . The footwear upper  14  may include one or more materials (for example, textiles, foam, leather, and synthetic leather), which may be stitched, adhesively bonded, molded, or otherwise formed to define an interior void configured to receive a foot. The material for the upper  14  may be selected and arranged to selectively impart properties such as durability, air-permeability, wear-resistance, flexibility, and comfort. 
     In the depicted embodiment, the outsole  16  includes a plurality of body segments  42  having different hardnesses, causing the total hardness of the outsole  16  to vary (e.g., increase) from the medial edge  26  to the lateral edge  24 . In the present disclosure, the term “hardness” means the resistance of a material to permanent deformation (e.g., permanent indentation). As a non-limiting example, the indentation hardness of the sole structure body  15  (e.g., the outsole  16 ) may increase from the medial edge  26  to the lateral edge  24  of the sole structure  12  in a stepped manner as shown in  FIG. 3 . As used herein, the term “indentation hardness” means the hardness of a material measured through a test in which the material is indentation until a permanent impression is formed. Indentation hardness tests include Vickers hardness test, Brinell hardness test, Knoop hardess test, Janka hardness test, Meyer hardness test, Rockwell hardness test, Shore hardness test, and Barcol hardness test. Although the drawings show the outsole  16  having the body segments, it is contemplated that any other sole structure body  15  may include the body segments  42  with different hardnesses. The different hardnesses of the body segments  42  serve as a training feedback tool for a golfer. In particular, because of the different hardness, the body segments  42  induce foot pronation during a golf swing. It is desirable to induce foot pronation during the follow through of a golf swing in order to maximize the distance and accuracy of a golf shot. 
     In the depicted embodiment, the sole structure body  15 , such as the outsole  16 , includes only three body segments  42 , namely, a first body segment  42   a , a second body segment  42   b , and a third body segment  42   c . It is contemplated, however, that the sole structure  15  may include more or fewer body segments  42 . The first body segment  42   a  extends along the forefoot region  22 , the midfoot region  20 , and the heel region  18 . The second body segment  42   b  extends along the forefoot region  22 , the midfoot region  20 , and the heel region  18 . The third body segment  42   c  extends along the midfoot region  20  and the heel region  18 . The third body segment  42   c  does not extend along the forefoot region  22 . The location of the first body segment  42   a , the second body segment  42   b , and the third body segment  42   c  with respect to the forefoot region  22 , the midfoot region  20 , and the heel region  18  of the sole structure  12 , as described above, aids in the inducement of proper foot pronation during a golf swing. 
     The first body segment  42   a , the second body segment  42   b , and the third body segment  42   c  are made of different materials each having a different hardness. For this reason, the sole structure  12  is referred to as a multi-durometer sole structure. In particular, the first body segment  42   a  is wholly or partly made of a first material having a first hardness, and the second body segment  42   b  is wholly or partly made of a second material having a second hardness. The hardness of the material forming the second body segment  42   b  (i.e. the second hardness) is greater than the hardness of the material forming the first body segment  42   a  (i.e., the first hardness). The third body segment  42   c  is wholly or partly made of a third material having a third hardness. The hardness of the material forming the third body segment  42   c  (i.e., the third hardness) is greater than the hardness of the materials forming the first body segment  42   a  (i.e., the first hardness) and the second body segment (i.e., the second hardness). The hardness of the materials, as described above, can help a golfer to maximize the energy transfer from the club to the ball during a golf swing by inducing proper foot pronation. 
     For example, the hardness of the material forming the first body segment  42   a  (i.e., the first hardness) may range between the twenty (20) Shore C and twenty-five (25) Shore C. The hardness of the material forming the second body segment  42   b  (i.e., the second hardness) may range between fifty (50) Shore C and fifty-five (55) Shore C. The hardness of the material forming the third body segment  42   c  may range between the eighty (80) Shore C and eight-five (85) Shore C. The hardness ranges, as described above, can help a golfer to maximize the energy transfer from the club to the ball during a golf swing by inducing proper foot pronation. 
     As a non-limiting example, the first body segment  42   a  may be wholly or partly made of an ethylene propylene diene monomer (M-class) (EDPM) rubber. The third body segment  42   c  may be wholly or partly made of nitrile butadiene rubber (NBR). The second body segment  42   b  may also be wholly or partly made of NBR with a lower acrylonitrile (ACN) content than the NBR forming the third body segment  42   c . The ACN content in the NBR influences the hardness of the NBR. As the ACN increases, the hardness of the NBR increases. Accordingly, the first body segment  42   a , the second body segment  42   b , and the third body segment  42   c  may all be made of NBR but with different ACN content. Specifically, the ACN content of the NBR forming the first body segment  42   a  is less than the ACN content of the NBR forming the second body segment  42   b , and the ACN content of the NBR forming the second body segment  42   b  is less than the ACN content of the NBR forming the third body segment  42   c.    
     The majority of the third body segment  42   c  is closer to the lateral edge  24  than to the medial edge  26  of the sole structure  12 . The majority of the first body segment  42   a  is closer to the medial edge  26  than to the lateral edge  24  of the sole structure  12 . The second body segment  42   b  is partly disposed between the first body segment  42   a  and the third body segment  42   c . The location of the first body segment  42   a , the second body segment  42   b , and the third body segment  42   c  with respect to the medial edge  26  and the lateral edge  24 , as described above, aids in the inducement of proper foot pronation during a golf swing. The first body segment  42   a  forms a majority of the forefoot region  22 , and the third body segment  42   c  forms a majority of the heel region  18  to induce pronation of the sole structure  12  toward the medial edge  26  during a golf swing. 
     The third body segment  42   c  defines a plurality of openings  44 , such as slots. Each opening  44  extends through the entire thickness of the third body segment  42   c  and is configured, shaped, and sized to receive a protrusion  46  of the second body segment  42   b . Accordingly, the second body segment  42   b  includes a plurality of protrusions  46  each extending through one of the openings  44  of the second body segment  42   b . The protrusions  46  are parallel to each other in order to induce foot pronation uniformly across a wearer&#39;s foot. Further, the protrusions  46  are disposed along the lateral edge  24  of the sole structure body  15 , and each protrusion  46  is obliquely angled relative to the central longitudinal axis X. Due to the orientation of the protrusions  46  relative to the central longitudinal axis X and the lateral edge  24 , the sole structure body  15  can comfortably support the user&#39;s foot while inducing foot pronation during a golf swing. 
     The first body segment  42   a  has a peripheral edge (i.e., the first peripheral edge  48 ) and a transitional edge (i.e., the first transitional edge  50 ). The first peripheral edge  48  coincides with (i.e., occupies the same space as) a portion of the medial edge  26 . The first transitional edge  50  includes a linear edge portion (i.e., the first linear edge portion  54 ) intersecting the forefoot edge  28  of the sole structure body  15 . The first linear edge portion  54  of the first body segment  42   a  may be parallel to the central longitudinal axis X. The first transitional edge  50  further includes a convex edge portion (i.e., the convex edge portion  56 ) directly connected to the first linear edge portion  54 . In addition, the first transitional edge  50  includes an angled edge portion (i.e. the first angled edge portion  58 ), which is obliquely angled relative to the central longitudinal axis X. The first angled edge portion  58  is directly connected to the convex edge portion  56 . The convex edge portion  56  allows most of the ball of the wearer&#39;s foot to be positioned on the “soft” material (i.e., the material forming the first body segment  42   a ), whereas the wearer&#39;s heel is mostly split between the second and third materials (i.e., the material forming the second body segment  42   b  and the third body segment  42   c ). In addition, the convex edge portion  56  also provides the golfer with a sense of “digging in,” thereby allowing the golfer to pre-load the front foot for an explosive downswing. Due to the convex edge portion  56  as well as the shape of the other transitional edges portions, the sole structure body  15  has a deformation gradient vector V, which is oriented toward the medial edge  26  and obliquely angled relative to the central longitudinal axis X when the sole structure  12  is loaded with a uniform pressure. Moreover, the first transitional edge  50  includes a curved edge portion (i.e., the first curved edge portion  60 ) directly connected to the first angled edge portion  58 . The first curved edge portion  60  intersects the medial edge  26 . Overall, the first transitional edge  50  abuts the second body segment  42   b . The structure, configuration, parts, and orientation of the first transitional edge  50 , as described above, can induce the user to properly pronate his foot during a golf swing. 
     The second body segment  42   b  includes a medial transitional edge (i.e., the second medial transitional edge  62 ), which has the same shape and configuration as the first transitional edge  50 . As such, the second medial transitional edge  62  abuts the first transitional edge  50 . In addition, the second body segment  42   b  has a lateral transitional edge (i.e., the second lateral transitional edge  64 ) abutting the third body segment  42   c . The second lateral transitional edge  64  intersects the lateral edge  24  and the heel edge  30  of the sole structure body  15  and includes a linear edge portion (i.e., the second linear edge portion  66 ). The second linear edge portion  66  intersects the lateral edge  24  of the sole structure body  15  and is obliquely angled relative to the central longitudinal axis X. The second lateral transitional edge  64  further includes a concave edge portion (i.e., the concave edge portion  68 ) directly connected to the second linear edge portion  66 . The concave edge portion  68  may have the same curvature as the convex edge portion  56 . The second lateral transitional edge  64  also includes an angled edge portion (i.e., the second angled edge portion  70 ) directly connected to the concave edge portion  68 . The second angled edge portion  70  is obliquely angled relative to the central longitudinal axis X. The second lateral transitional edge  64  also includes a curved edge portion (i.e. the second curved edge portion  72 ) connected to the second angled portion  70 . The second curved edge portion  72  intersects the heel edge  30  and may have the same curvature as the first curve edge portion  60 . The structure, configuration, parts, and orientation of the second lateral transitional edge  64 , as described above, can induce the user to properly pronate his foot during a golf swing. The third body segment  42   c  has a medial transitional edge (i.e., the third medial transitional edge  74 ), which has the same shape and configuration as the second lateral transitional edge  64 . In addition, the third body segment  42   c  has a peripheral edge (i.e., the third peripheral edge  76 ) that coincides with (i.e., occupies the same space as) at least a portion of the lateral edge  24  of the sole structure body  15 . The structure, configuration, parts, and orientation of the third peripheral edge  76 , as described above, can induce the user to properly pronate his foot during a golf swing. Each of the transitional edges (e.g., the first transitional edge  50  and the second lateral transitional edge  64 ) can at least partially overlap to provide a smoother hardness gradient. In particular, each of the transitional edges (e.g., the first transitional edge  50  and the second lateral transitional edge  64 ) is directly connected to a transitional surface  57  that is obliquely angled relative to the central longitudinal axis X. As a result, the body segments (i.e., the first body segment  42   a , the second body segment  42   b , and the third body segment  42   c ) at least partially overlap along the thickness of the sole structure body  15  in order to provide a smoother hardness gradient as shown in  FIG. 3 . On a backswing, the present sole design allows the front foot to pronate with a bias toward dropping the medial ball of the foot. This preloads the foot position to permit a powerful forward ankle roll/foot supination as weight is shifted forward. Conversely, the present sole design allows the back foot to collapse/pronate as weight is shifted toward the front foot. As a consequence, the sole structure  12  facilitates a more explosive weight transfer during the downswing 
     While the best modes for carrying out the teachings have been described in detail, those familiar with the art to which this disclosure relates will recognize various alternative designs and embodiments for practicing the teachings within the scope of the appended claims.