FOOTWEAR CONSTRUCTION WITH HEEL SUPPORT ASSEMBLY

Abstract

An article of footwear having a heel support assembly with a memory foam layer situated internally of a heel counter is provided. The memory foam layer may be laminated to the heel counter, for example, by adhesive or direct attachment. The heel memory foam layer may have a maximum thickness that is sufficient to embrace the heel of the wearer's foot potentially cradling the calcaneus, the retrocalcaneal bursa and the base of the Achilles tendon. The heel support assembly may also include a heel cradle extending around an external portion of the upper and including a lasting allowance. The heel cradle can provide torsional support in the arch region (or waist) of the article of footwear, for example when the heel support assembly is incorporated into an article of footwear with a strobel construction.

Claims

1. An article of footwear comprising: a sole: an upper joined to the sole, the upper include a heel counter assembly disposed in the heel region of the upper, the heel counter assembly including a heel counter and a memory foam layer, the memory foam layer having a maximum thickness of at least 7 mm, the upper further including a transition foam layer disposed above the heel counter assembly having a maximum thickness less than the maximum thickness of the memory foam layer; and a heel cradle extending around the heel region of the upper into the arch region of the upper.

2. The article of footwear of claim 1 wherein the heel cradle includes a lasting allowance disposed between and secured to the upper and the sole.

3. The heel support assembly of claim 1 wherein the memory foam layer is laminated to the heel counter.

4. The heel support assembly of claim 1 wherein the memory foam layer is molded to the heel counter.

5. The heel support assembly of claim 1 further including an overlay extending laterally around the upper, the overlay being substantially coextensive with the heel counter.

6. The article of footwear of claim 1 wherein the upper includes a strobel construction.

7. The heel support assembly of claim 1 wherein the heel cradle includes a medial portion, a lateral portion, and an intermediate portion therebetween, the intermediate portion having a reduced height relative to the medial and lateral portions of the heel cradle.

8. The heel support assembly of claim 1 wherein the transition foam layer includes a maximum thickness of less than or equal to 3 mm.

9. The heel support assembly of claim 1 wherein the memory foam layer includes a tapered peripheral edge.

10. The heel support assembly of claim 9 wherein the thickness of the tapered peripheral edge of the memory foam layer is generally equal to the thickness of the transition foam layer.

11. A heel support assembly for an article of footwear including an upper and a sole, the heel support assembly comprising: a heel counter assembly including: a heel counter disposed adjacent to a heel portion of the upper of the article of footwear, and a memory foam layer positioned internally of the heel counter, the memory foam layer being substantially coextensive with the heel counter; and a u-shaped heel cradle extending around an exterior portion of the upper and including a medial portion and a lateral portion each having a lasting allowance extending inwardly between the upper and the sole.

12. The heel support assembly of claim 11 further including an overlay substantially encompassing the heel counter assembly along the exterior portion of the upper.

13. The heel support assembly of claim 11 wherein the memory foam layer includes a tapered peripheral edge.

14. The heel support assembly of claim 11 wherein the memory foam layer is laminated to the heel counter.

15. The heel support assembly of claim 11 wherein the memory foam layer is molded to the heel counter.

16. A method of manufacturing an article of footwear comprising: joining a memory foam layer to a heel counter to form a heel counter assembly; securing the heel counter assembly to a heel portion of an upper; positioning a u-shaped heel cradle over a base of the upper, the heel cradle including a medial portion, a lateral portion, and an intermediate portion therebetween; and securing a sole to the upper, the medial and lateral portions each including a lasting allowance disposed between the sole and the upper.

17. The method of claim 16 wherein joining the memory foam layer to the heel counter includes laminating the memory foam layer to the heel counter.

18. The method of claim 16 wherein joining the memory foam layer to the heel counter includes molding the memory foam layer to the heel counter.

19. The method of claim 16 wherein securing the heel counter assembly to the heel portion of the upper includes gluing the heel counter assembly to the upper.

20. The method of claim 16 further including positioning an overlay around a heel portion of the upper, the overlay being substantially coextensive with the heel counter assembly.

21. (canceled)

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0016] FIG. 1 is a perspective view of a boot incorporating a footwear construction in accordance with an embodiment of the present invention.

[0017] FIG. 2 is an exploded perspective view of the boot of FIG. 1.

[0018] FIG. 3 is a cross-sectional view of the boot of FIG. 1.

[0019] FIG. 4 is a bottom perspective view of the upper with the cradle installed.

[0020] FIG. 5 is a close-up cross-sectional view of the heel counter assembly of FIG. 3.

[0021] FIG. 6 is a perspective view of the heel cradle.

[0022] FIG. 7 is a sectional view similar to FIG. 3 showing the wearer's foot situated in the boot.

[0023] FIG. 8 is an exploded perspective view of an alternative embodiment incorporating an alternative transition foam layer.

DESCRIPTION OF THE CURRENT EMBODIMENT

[0024] Referring now to FIGS. 1 and 2, an article of footwear including a heel support assembly of a current embodiment is illustrated and generally designated 10. For purposes of disclosure, the article of footwear 10 is illustrated as a work boot. Embodiments of the invention may, however, be incorporated into essentially any style or type of footwear that incorporates a closed heel. For example, embodiments of the invention may be incorporated into essentially any safety shoes, safety boots, work shoes, work boots, athletic shoes, running shoes, sneakers, tennis shoes, hiking shoes, hiking boots, biker boots, boat shoes, deck shoes, dress shoes, military footwear, uniform footwear and sandals with a closed heel.

[0025] Referring again to FIGS. 1 and 2, the article of footwear 10 generally includes an upper 12 and a sole 14. The upper 12 may be essentially any footwear upper. The current embodiment is described in the context of a lightweight athletic-inspired upper, the bottom of which is closed by a flexible strobel board 15 along a butt seam. The upper 12 includes a vamp 16 (or toe box), a tongue 18 and one or more quarters 20. The vamp 16 generally forms the forefoot portion of the upper 16 and may be manufactured from any combination of pieces of upper material. The tongue 18 may be joined to the vamp 16 and extend rearwardly to underlie the laces 22. As with the vamp 16, the tongue 18 may be manufactured from any combination of pieces. The tongue 18 may be padded, which in part helps to protect the wearer's foot from the laces 22. The quarter or quarters 20 form the heel portion of the upper 12 and may be manufactured from any combination of pieces of upper material. The various pieces of the upper 12 may be manufactured from any of a wide range of materials, such as leather, synthetic leather, mesh, canvas, textile (e.g. woven, knit, bonded), fabric and molded components.

[0026] The upper 12 may include various trim, cushioning and reinforcing elements. For example, a toe cap (not shown) may be provided to reinforce the vamp 16. Further, padding may be sandwiched between the layers of the upper 12, such as between the vamp 16 and an internal liner 24. Reinforcing elements may be affixed to the upper 12 to reinforce the portions of the upper 12 that receive the laces. The interior of the upper 12, such as the vamp 16, tongue 18, and quarters 20, may be covered by the liner 24, for example a layer of DriLex, Cambrelle or other lining materials. The liner 24 may be a single layer of material or it may be a combination of materials. For example, the liner 24 may include integrated padding throughout or in select regions, such as around the ankle and the foot opening. The construction of the illustrated upper 12 is merely exemplary, and the present invention may be incorporated into footwear that includes essentially any upper construction.

[0027] As noted above and shown in FIGS. 1 and 2, the article of footwear 10 includes a sole 14. For purposes of disclosure, the current embodiment is described in the context of a generally conventional sole, including a midsole 26 and an outsole 28. The midsole 26 provides energy absorption and foot support, and the outsole 28 includes a wear surface (not shown) and a sidewall 30. Greater or fewer elements of the sole 14 can be included in other embodiments. For example, some embodiments can include only an outsole, while other embodiments can include an outsole, a midsole, and an insole. Still other embodiments can include a unit sole, in which the midsole and the outsole are combined into a unitary element. The construction of the illustrated sole 14 is merely exemplary, and the present invention may be incorporated into footwear that includes essentially any sole construction.

[0028] Referring now to FIG. 3, a heel support assembly in accordance with a current embodiment is illustrated and generally designated 32. The heel support assembly 32 includes a heel counter 34, a memory foam layer 36 (collectively referred to as a heel counter assembly 38) and a heel cradle 40. The heel counter assembly 38 is positioned between the upper 12 and the liner 24, and the heel cradle 40 is positioned outside of the upper 12, extending forwardly toward the wearer's arch. Each such element is discussed below.

[0029] The heel counter 34 of the heel counter assembly 38 is shaped to conform to the heel of the article of footwear 10 and provide rigid support to an otherwise flexible upper 12. As perhaps best shown in FIG. 5, the heel counter 34 includes a curved sidewall 42 with an arcuate top edge 44 that gradually tapers from a maximum height adjacent the rear of the heel to a minimum height forward of the heel. For example, the curved sidewall 42 includes a continuously downwardly curving top edge 44, terminating at or near the wearer's arch. The curved sidewall 42 also includes a concave inner surface 48 and a convex outer surface 50 defining a generally uniform thickness therebetween. The heel counter 34 optionally includes a bottom flange 46 that is turned under and extends beneath the wearer's heel, such that the bottom flange 46 is sandwiched between the stroble board 15 (or other insole element) and the midsole 26 (or other outsole element). The heel counter 34 can be a unitary element, or can be formed from two or more optionally interconnected elements. The heel counter 34 is formed from a thermoplastic in the current embodiment, for example thermoplastic polyurethane, but can be formed from other materials in other embodiments as desired.

[0030] The memory foam layer 36 of the heel counter assembly 38 is adapted to provide enhanced comfort for the rear and side portions of the wearer's heel. As used herein, a memory foam layer means a slow recovery foam element having a two-dimensional or three-dimensional shape such that, when pressure is applied and released, the slow recovery foam element returns to substantially its original shape. The memory foam layer can include viscoelastic polyurethane foam and low-resilience polyurethane foam for example. The memory foam layer 36 is formed as a sheet-like element in some embodiments, while in the illustrated embodiment the memory foam layer 36 can be formed with a three-dimensional shape. For example, a flat or tapered-flat memory foam layer 36 can applied to the interior of the heel counter 34, such that the memory foam layer 36 assumes a convex curvature and is coextensive with the concave inner surface 48 of the heel counter sidewall 42. In other embodiments a pre-shaped memory foam layer 36 is applied to the interior of the heel counter 34, being pre-shaped with a convex surface that is coextensive with the concave inner surface 48 of the heel counter sidewall 42. The memory foam layer 36 is laminated to the concave inner surface 48 of the heel counter sidewall 42 by adhesive in some embodiments, while in other embodiments the memory foam layer 36 is molded directly to the concave inner surface 48 of the heel counter 34 so that they become intimately attached as the memory foam cures.

[0031] The thickness of the memory foam layer 36 can be selected to provide optimized support to the rear and side portions of the wearer's heel. As used herein, the thickness of the memory foam layer 36 includes the distance between substantially opposing major surfaces of the memory foam layer 36. The memory foam layer 36 may have a maximum thickness that is sufficient to embrace the heel of the wearer's foot potentially cradling the calcaneus, the retrocalcaneal bursa and the base of the Achilles tendon. For example, the memory foam layer 36 may have a maximum thickness of approximately 10 mm. The maximum thickness may, however, vary from application to application, for example, in the range of about 7 mm to about 30 mm. In addition, the memory foam layer 36 can maintain a substantially constant thickness along its height in some embodiments. For example, the thickness at the rearward-most portion of the memory foam layer 36 (in the heel-toe direction) can be relatively constant. More particularly, the thickness can be least 7 mm, further optionally about 10 mm. In other embodiments, the memory foam layer 36 includes a thickness that varies along its height. For example, and as shown in FIG. 5, the maximum thickness of the memory foam layer 36 can occur midway between the upper and lower edges of the memory foam layer. In this example, the maximum thickness is at least 7 mm, further optionally about 10 mm. The thickness of the memory foam layer 36 transitions or tapers to a reduced thickness at its periphery, terminating at a thickness less than the maximum thickness, for example 1 mm to 3 mm, inclusive. The memory foam layer 36 can assume other thicknesses in other embodiments.

[0032] As noted above, the memory foam layer 36 is situated internally of the heel counter 34 closest to the wearer's heel to form the heel counter assembly 38. The periphery of the memory foam layer 36 can be shaped according to the intended embodiment. In one embodiment, the heel memory foam layer is somewhat dome-shaped having maximum thickness through a center region and tapering gradually thinner toward its peripheral edge. In another embodiment, the memory foam layer 36 can include a rearwardly-chamfered or rearwardly-beveled upper portion 52 that generally follows the contour of the heel counter upper edge 44. In still other embodiments, the memory foam layer 36 can include a flat upper portion 52 that generally follows the contour of the heel counter upper edge 44 and a flat bottom edge 54 that straddles the wearer's heel. The heel counter assembly 38 is positioned between the upper 12 and the liner 24 in the present embodiment, but can be positioned to directly engage the wearer's foot in other embodiments.

[0033] The heel cradle 40 is shaped to provide external heel support to the upper while also aiding in the removal of the article of footwear 10. As perhaps best shown in FIG. 4, the heel cradle 40 is generally u-shaped and extends around an exterior portion of the upper immediately above and adjacent to the sole 14. That is, the heel cradle 40 extends forwardly into the arch region (or waist) of the article of footwear 10 to provide additional torsional control. This additional torsional control may be particularly beneficial when incorporated into footwear with more flexible constructions, such as a strobel construction. The heel cradle 40 includes a medial portion 56, a lateral portion 58, and an intermediate portion therebetween 60. The medial and lateral portions 56, 58 are spaced apart from each other by the width of the intermediate portion 60 and generally mirror each other. The medial and lateral portions 56, 58 define a height greater than a height defined by the intermediate portion 60, such that the intermediate portion 60 represents a dip in the rear profile of the heel cradle 40. In addition the medial and lateral portions 56, 58 each include a lasting allowance in the form of one or more projections 62 that extend under the upper 12 and are secured to the sole 14. In other words, the lasting allowance of the medial portion 56 extends toward the lasting allowance of the lateral portion 58. The intermediate portion 60 includes a thickness, protruding from the rear of the upper, to provide a shelf 64. The shelf 64 is conveniently placed to provide an area for removing the article of footwear 10 with downward pressure. Consequently, the heel cradle is generally rigid, being formed for example from thermoplastic polyurethane, but can be formed from other materials in other embodiments as desired. In addition, the shorter intermediate portion 60 can provide improved comfort in some applications by allowing some degree of flexibility in the portion of the heel overlying the retrocalcaneal bursa.

[0034] The heel support assembly 32 is described above as including a heel counter assembly 38 (heel counter 34 and memory foam layer 36) and a heel cradle 40, but can include greater or fewer elements that provide support to the heel area of the upper 12. For example, the heel support assembly 32 can include only the heel counter assembly 38 in some embodiments. In other embodiments, the heel support assembly 32 can include an overlay 66 that extends around the sides and back of the heel portion of the upper 12, being layered between the upper 12 and the heel cradle 40. This overlay 66 is generally depicted in FIG. 1. The overlay 66 is formed from the same material as the upper 10 in the present embodiment (e.g., leather), but can be formed from a material different from that of the upper 10 in other embodiments as desired. For example, the overlay 66 can be formed from synthetic leather, nylon, or other materials in other embodiments as desired. The overlay 66 may be substantially coextensive with the heel counter 34. However, it may have a different size and/or shape than the heel counter 34. For example, the overlay 66 may be somewhat smaller or somewhat larger than the heel counter 34.

[0035] Referring again to FIGS. 3, 7 and 8, the upper 10 includes a transitional memory foam layer 68 integrated into the ankle region of the upper 12 immediately above the heel counter 34. The transitional memory foam layer 68 is formed from a memory foam material, optionally the same memory foam material than the heel memory foam layer 36. In other embodiments the transitional foam layer 68 is formed from a different (non-memory) foam material. The transitional foam layer 68 is situated immediately above the heel memory foam layer 36 to provide a smooth transition along the inside of article of footwear 10. The transitional foam layer 68 may be tapered to increase in thickness as it approaches the heel counter 34. As shown in FIG. 8 for example, the transitional foam layer 68 may transition from a thickness of about 1 mm at the top to a thickness of about 3 mm at the bottom adjacent to the top of the heel counter 34. The maximum thickness of the transitional memory foam layer 68 is generally smaller than the maximum thickness of the heel memory foam layer 36. For example, the transitional memory foam layer 68 maximum thickness is approximately 3 mm in one embodiment, while the maximum thickness of the heel memory foam layer 36 is approximately 10 mm in this embodiment. In this respect, the ratio of the heel memory foam layer 36 maximum thickness to the transitional memory foam layer 68 maximum thickness is at least 3:1, further optionally at least 5:1, and still further optionally at least 10:1. This maximum thickness of the transitional memory foam layer 68 is merely exemplary and the thickness may be in the range of about 1 mm to about 20 mm. As shown in FIGS. 3, 7 and 8, the upper edge of the 52 of the heel memory foam layer 36 can also include a thickness equal to the thickness of the transitional memory foam layer 68 where they meet to provide a flush interface.

[0036] The article of footwear 10 can also include an insole 70 specifically configured to interact with the heel support assembly 32. The insole 70 can be manufactured from a material that is highly resistant to compression set. For example, the insole 70 can be manufactured from a material having a compression set of 5% after 500,000 compressions and a recovery period of 24 hours. Example insole materials include cast-mold polyurethane, pour molded polyurethane, and expanded thermoplastic polyurethane, available under the name Infinergy from BASF.

[0037] To reiterate, the article of footwear 10 of the current embodiment includes a heel support assembly 34 with a memory foam layer 36 incorporated into the heel counter 34. The memory foam layer 36 may be laminated to the interior of the heel counter 34 and may have a thickness in the range of 7 mm to 30 mm. The upper 12 may include a transitional foam layer 68 that is disposed above the heel counter 34 to assist in fitting a wearer's foot into the interior of the article of footwear 10. The transitional foam layer 68 may be configured to provide a gradual entry into the memory foam 36 of the heel counter 34. The transitional foam layer 68 may be tapered to increase in thickness as it approaches the heel counter 34, generally shown in FIG. 8 for example. Further by example, the transitional foam layer 68 may transition from a thickness of about 1 mm at the top to a thickness of about 3 mm at the bottom adjacent to the top of the heel counter 34. The heel support assembly 32 may also include an optionally leather overlay 66 and a heel cradle 40 that contributes to the unique overall characteristics of the assembly 32. The cradle 40 of the illustrated embodiment includes a lasting allowance 62 in the arch or waist region of the article of footwear 10 that helps to reinforce the heel region of the article of footwear 10 and to provide a degree of torsional control through the heel and arch regions. The article of footwear 10 may have a strobel construction and the cradle 40 may be configured to add heel and torsional support that would not otherwise be available with a conventional strobel construction.

[0038] An article of footwear incorporating a heel support assembly in accordance with a current embodiment can be formed according to the following steps, discussed individually below: a) joining a memory foam layer to a heel counter to form a heel counter assembly; b) securing the heel counter assembly to a heel portion of an upper; c) joining an overlay to the heel portion of the upper; d) positioning a heel cradle having a lasting allowance over a base of the upper; and e) securing a sole to the upper, such that the lasting allowance is disposed between the upper and the sole. While the foregoing manufacturing steps are recited in connection with the illustrated embodiments, the manufacturing steps can vary from application to application as desired, such that greater or fewer method steps can be used in connection with other embodiments.

[0039] Joining a memory foam layer to a heel counter includes fixedly attaching the memory foam layer to the concave interior surface of the heel counter. This step can include, for example, laminating the memory foam layer to the heel counter by adhesive. Also by example, this step can include molding the memory foam layer directly to the heel counter. Still further by example, this step can include positioning an intermediate adhesive layer between the heel counter and the memory foam layer, such that that the memory foam layer is indirectly attached to the heel counter. The memory foam layer is fixed with respect to the heel counter in these examples, such that that the memory foam layer cannot be removed without damaging the integrity of the memory foam layer. As noted above, the memory foam layer can be a flat foam sheet. For example, a flat memory foam layer can be applied to the interior of the heel counter, such that the memory foam layer assumes a convex mating surface that bonds with the concave inner surface of the heel counter sidewall. Alternatively, the memory foam layer can be molded with a three-dimensional contour. For example, a pre-shaped memory foam layer can be applied to the interior of the heel counter, being pre-shaped with a convex mating surface that is coextensive with the concave inner surface of the heel counter.

[0040] Securing the heel counter assembly to a heel portion of an upper includes gluing the heel counter assembly to the upper in the current embodiment. For example, the heel counter assembly can be glued between a portion of the upper and a liner. In this position, the upper can be strobel lasted such that the upper is closed by a strobel board, thereby providing flexibility in the upper, while the heel counter assembly is securely positioned therein. Joining an overlay about the heel portion of the upper includes attaching the overlay to the exterior of the upper, for example using an adhesive. The overlay can be substantially coextensive with the heel counter or can have a different size and/or shape than the heel counter. In addition, the overlay is formed from the same material as the upper in the current embodiment, but can be formed from a material different from that of the upper in other embodiments as desired. For example, the overlay can be formed from synthetic leather, nylon, or other materials.

[0041] The steps of positioning a heel cradle over a base of the upper and securing the sole to the upper provide an article of footwear having a reinforced heel. The heel cradle is rigid in the current embodiment, being molded from thermoplastic polyurethane having u-shaped construction that extends around the heel region of the upper. The heel cradle is also molded to have a shortened intermediate portion that provides a shelf to aid the wearer in removing the article of footwear with downward pressure. The sole can be secured to the upper according to any desired technique, for example by gluing a midsole to the strobel board. Optional further manufacturing steps can include positioning an insole within the upper and over the strobel board, the insole being specifically configured to interact with the heel support assembly. The insole can be manufactured from a material that is highly resistant to compression set. For example, the insole may be manufactured from a material having a compression set of 5% after 500,000 compressions and a recovery period of 24 hours. Suitable insole materials include cast-mold polyurethane, pour-molded polyurethane, and expanded thermoplastic polyurethane, for example.

[0042] Directional terms, such as vertical, horizontal, top, bottom, upper, lower, inner, inwardly, outer and outwardly, are used to assist in describing the invention based on the orientation of the embodiments shown in the illustrations. Further, the terms medial, lateral and longitudinal are used in the manner commonly used in connection with footwear. For example, when used in referring to a side of the shoe, the term medial refers to the inward side (that is, the side facing the other shoe) and lateral refers to the outward side. When used in referring to a direction, the term longitudinal direction refers to a direction generally extending along the length of the shoe between toe and heel, and the term lateral direction refers to a direction generally extending across the width of the shoe between the medial and lateral sides of the shoe. The use of directional terms should not be interpreted to limit the invention to any specific orientation. As used above, the term arch region (or arch or midfoot) refers generally to the portion of the footwear or sole assembly corresponding to the arch or midfoot of the wearer's foot; the term forefoot region (or forefoot) refers generally to the portion of the footwear forward of the arch region corresponding to the forefoot (for example, including the ball and the toes) of a wearer's foot; and the term heel region (or heel) refers generally to that portion of the footwear rearward of the arch region corresponding to the heel of the wearer's foot.

[0043] The above description is that of current embodiments of the invention. Various alterations and changes can be made without departing from the spirit and broader aspects of the invention as defined in the appended claims, which are to be interpreted in accordance with the principles of patent law including the doctrine of equivalents. This disclosure is presented for illustrative purposes and should not be interpreted as an exhaustive description of all embodiments of the invention or to limit the scope of the claims to the specific elements illustrated or described in connection with these embodiments. For example, and without limitation, any individual element(s) of the described invention may be replaced by alternative elements that provide substantially similar functionality or otherwise provide adequate operation. This includes, for example, presently known alternative elements, such as those that might be currently known to one skilled in the art, and alternative elements that may be developed in the future, such as those that one skilled in the art might, upon development, recognize as an alternative. Further, the disclosed embodiments include a plurality of features that are described in concert and that might cooperatively provide a collection of benefits. The present invention is not limited to only those embodiments that include all of these features or that provide all of the stated benefits, except to the extent otherwise expressly set forth in the issued claims. Any reference to claim elements in the singular, for example, using the articles a, an, the or said, is not to be construed as limiting the element to the singular.