US20110179669A1 - Cushioning and shock absorbing midsole - Google Patents

Abstract

A midsole adapted for attachment to a shoe having multiple layers of varying materials each having a different hardness level. More particularly, the present midsole includes a top, middle and bottom layer wherein all three layers of material have a different hardness range and wherein at least one of the layers is made from thermoplastic rubber (TPR). In one embodiment, the thermoplastic rubber (TPR) layer lies between the top and bottom layers and in another embodiment, the thermoplastic rubber (TPR) layer is the bottom layer. The thermoplastic rubber (TPR) layer may also have a length shorter than the other two layers forming the midsole.

Description

BACKGROUND OF THE INVENTION
• The present invention relates generally to the construction of a shoe and, more particularly, to a midsole construction with improved comfort and shock absorption to enhance the comfort of a user's foot.
• The footwear industry has seen numerous design features introduced over the years in order to enhance the comfort, cushioning, resiliency and shock absorption capabilities of a shoe. Many of the technological advances have occurred in the sole, particularly the midsole. In most footwear, the midsole often provides both protective cushioning and shock absorption for the user's foot. In an effort to provide improved performance, it is often desirable to vary the support characteristics of the sole from one region to another. A wide variety of soles have been developed to provide variable support for the foot. These advances include using air cushioning systems such as air cavities or air bladders disposed within the sole of a shoe Although a marked improvement over conventional uniform sole constructions has occurred over the years, there still remains a need for a midsole construction that can be adapted to provide additional comfort and shock absorption to the wearer's foot.
• It would therefore be desirable to provide an improved midsole construction which is capable of providing increased comfort and shock absorption for the foot without using air cavities and/or air bladders to achieve the same.
SUMMARY OF THE INVENTION
• A shoe is generally composed of an upper connected to a sole. The sole of a shoe is generally comprised of an outsole, a midsole, an insole, and on occasion, a sock liner. The present invention is directed to an improved midsole construction having multiple layers of varying materials, each layer of material having a different hardness/softness level.
• In one aspect of the present invention, a midsole is provided which includes a three-layered construction, namely, a top layer, a middle layer and a bottom layer. The top layer provides a layer of material between the insole of the shoe and the second or middle layer of the midsole; the middle layer provides cushioning to the foot; and the bottom layer provides additional cushioning and a contacting surface for the outsole. In one embodiment, the top layer is made of a polyurethane material with a hardness in the range of 60-90° Asker C hardness, the middle layer is made of a thermoplastic rubber material with a hardness in the range of 20-65° Asker C hardness, and the bottom layer is made of a polyurethane material with a hardness in the range of 20-50° Asker C hardness. In one embodiment, the middle layer spans the heel portion of the shoe only and includes an upper surface which mates with and attaches to a portion of the bottom surface of the top layer and a bottom surface which mates with and attaches to a portion of the upper surface of the bottom layer. As a result, in the forefront area of the shoe, the bottom surface of the top layer mates with and attaches directly to the upper surface of the bottom layer. The bottom layer provides a layer of material between the outsole of the shoe and the second or middle layer of the midsole in the heel portion of the shoe and a layer of material between the outsole of the shoe and the top layer of the midsole in the forefront portion of the shoe. The three layers of the midsole have varying hardness/softness levels with the top layer being harder than the middle and bottom layers and with the middle layer being harder than the bottom layer. These layers can be attached to each other by any suitable means such as cement adhesion and/or stitching.
• In another embodiment, the three layers of material forming the midsole are re-arranged such that the top layer is harder than the middle and bottom layers but the middle layer is softer than the bottom layer. In one embodiment, the bottom layer has an upper surface which mates with and attaches to only a portion of the bottom of the middle midsole layer and the bottom surface thereof mates with and attaches to a portion of the upper surface of the outsole in the heel portion of the shoe. In this particular embodiment, the middle layer of the midsole attaches directly to the upper surface of the outsole in the forefront portion of the shoe.
• It is an object of the present invention to provide a midsole which provides enhanced comfort and shock absorption by utilizing multiple layers of varying materials which are likewise of varying hardness/softness levels.
• Specific advantages and features of the present midsole construction will be apparent from the accompanying drawings and the description of the several embodiments of the present invention.
DESCRIPTION OF THE DRAWINGS
• FIG. 1 is a perspective view of one embodiment of a shoe constructed in accordance with the teachings of the present invention.
• FIG. 2 is an exploded view of the shoe ofFIG. 1 showing construction of the midsole.
• FIG. 3 is an exploded view of the embodiment of the midsole shown inFIG. 2.
• FIG. 4 is an exploded view of another embodiment of the midsole of the shoe shown inFIG. 1.
• FIG. 5 is an exploded view of the embodiment of the midsole shown inFIG. 4.
• FIG. 6 is a rear elevational view of the bottom layer of the midsole embodiment shown inFIGS. 4 and 5.
• It should be understood that the drawings are not necessarily to scale and that the embodiments disclosed herein are sometimes illustrated by fragmentary views. In certain instances, details which are not necessary for an understanding of the present invention or which render other details difficult to perceive may have been omitted. It should also be understood that the invention is not necessarily limited to the particular embodiments illustrated herein. Like numbers utilized throughout the various figures designate like or similar parts or structure.
DETAILED DESCRIPTION
• A shoe generally includes an upper and a sole assembly that is affixed to the upper. The sole assembly generally includes an insole, a midsole, and an outsole, each having a peripheral shape designed to conform to the shape of a wearer's foot. To facilitate disclosure of the present invention, reference will be made to various general areas of the foot, such as the heel, arch and forefoot areas. When used to refer to locations on the various sole components, these terms should be interpreted to include those areas of the midsole and outsole that are disposed generally (and not necessarily directly) beneath the corresponding elements of the foot. It should be understood, however, that the boundaries between the heel, arch and forefoot areas are not precise and that these terms should be interpreted loosely and with a great deal of flexibility.
• Referring now to the drawings and, in particular,FIGS. 1-3, a first embodiment of a new and improved shoe midsole construction having multiple layers embodying the principles and concepts of the present invention and generally designated by thereference numeral20 inFIGS. 2 and 3 will be described.
• A shoe12 (FIG. 1) generally includes an upper14 and asole assembly16 that is affixed to the upper14.Sole assembly16 typically includes aninsole18, amidsole20, and anoutsole22 and is attached to the upper14 using a conventional method of attachment such as an adhesive, stitching or injection molding. In the embodiment illustrated inFIG. 1, theinsole18 is formed as part of the upper14. Themidsole20 includes three layers, atop layer24, amiddle layer26 and abottom layer28. Themidsole20, as shown inFIGS. 2 and 3, has anupper surface30 and abottom surface32. Thetop layer24 of themidsole20 can be attached via conventional means to either an insole such asinsole18, or to the upper14, while thebottom surface32 ofbottom layer28 is attached to theoutsole22 using a conventional method of attachment.
• Top layer24 of themidsole20 is positioned below theinsole18 and above themiddle layer26 of themidsole20. The specific material of thetop layer24 may be chosen depending upon the nature and type of shoe in which it will be used.Top layer24 may be made from a variety of materials including, but not limited to, molded Polyurethane (PU), Polyvinyl Chloride (PVC), Thermoplastic Urethane (TPU), Thermoplastic Rubber (TPR), vulcanized rubber, ethyl vinyl acetate (EVA), rubberlon, or any other synthetic or natural material. The material forming thetop layer24 has a hardness factor greater than the middle andbottom layers26 and28 and is generally in the range of 60-90° Asker C hardness. The material and hardness/softness ranges selected will be determined by the type of footwear onto whichmidsole20 is intended to be placed.
• Lying underneathtop layer24 of themidsole20 is amiddle layer26 having anupper surface36 and abottom surface40. In the embodiment illustrated inFIGS. 2 and 3, themiddle layer26 only extends across the heel portion oftop layer24 andbottom layer28 and may be made from a variety of materials including, but not limited to, TPR. Theupper surface36 ofmiddle layer26 is attached to thebottom surface34 of thetop layer24 at the heel portion of the sole16 using a conventional method of attachment, such as adhesive, while thebottom surface40 of themiddle layer26 is attached to theupper surface38 of thebottom layer28 in the heel portion of the sole16. In contrast, thebottom surface34 of thetop layer24 is attached directly to theupper surface38 ofbottom layer28 in the arch and forefoot areas of the sole16. Themiddle layer26 may further be secured to thetop layer24 by utilizing male connection portions, projections orcomponents42 associated with thebottom surface34 of thetop layer24 whichportions42 mate with and engage corresponding female connection portions, openings orcomponents44 associated with themiddle layer26 as best shown inFIG. 3. Regardless of the type of material used for themiddle layer26, themiddle layer26 is softer than thetop layer24 and is generally of a hardness in the range of 20-65° Asker C hardness, and preferably in the range of 40-60° Asker C hardness.
• Thebottom layer28 of thepresent midsole20 is positioned below themiddle layer26 in the heel area of the sole16 and below thetop layer24 in the arch and forefront areas of the sole16 and above theoutsole22. The specific material of thebottom layer28 may again be chosen depending upon the nature and type of shoe in which it will be used. Thebottom layer28 may be made from a variety of materials including, but not limited to, molded Polyurethane (PU), Polyvinyl Chloride (PVC), Thermoplastic Urethane (TPU), Thermoplastic Rubber (TPR), vulcanized rubber, EVA, rubberlon, or any other synthetic or natural material. The material forming thebottom layer28 has a hardness factor which is softer than both thetop layer24 and themiddle layer26 and is generally in the range of a 20-50° Asker C hardness, and preferably in the range of 20-40° Asker C hardness. The material and hardness/softness ranges selected will again be determined by the type of footwear onto which midsole20 is intended to be placed. Theupper surface38 of thebottom layer28 of themidsole20 is attached to thebottom surface40 of themiddle layer26 of themidsole20 in the heel portion of the sole16 using a conventional method of attachment, while theupper surface38 of thebottom layer28 of themidsole20 in the arch and forefront areas of theshoe16 is attached directly to thebottom surface34 of thetop layer24 of the midsole likewise using conventional means.
• In the particular embodiment illustrated inFIGS. 2 and 3, themiddle layer26 ofmidsole20 is utilized to provide additional comfort to the wearer of theshoe12 in that themiddle layer26 acts as a cushioning means to further cushion the heel of the wearer as the heel portion of theshoe12 strikes the ground during a normal gait. In some embodiments, themiddle layer26 may be comprised of a gel type material which provides increased shock absorption and energy return whereas the top andbottom layers24 and28 of themidsole20 can be made of a dual density lightweight material which likewise provide support and shock absorption. It is also recognized and anticipated that in some embodiments, themiddle layer26 of themidsole20 may extend beyond the heel portion of the sole16 to include the arch area and/or forefoot area of the sole16 as well, or portions thereof. Regardless of the types of materials used for each of the threeseparate layers24,26 and28 associated with thepresent midsole construction20, improved comfort and cushioning is achieved in this particular midsole construction due to the fact that thetop layer24 of themidsole20 is harder than themiddle layer26 of themidsole20, which, in turn, is harder than thebottom layer28 of themidsole20. Stated another way, thebottom layer28 is softer than themiddle layer26 which, in turn, is softer than thetop layer24 of themidsole construction20. This arrangement of layers and hardness factors provides for improved comfort and cushioning to the wearer of theshoe12.
• In another embodiment, referring now to the drawings and, in particular,FIGS. 4-6, a second embodiment of a new and improved shoe midsole construction having multiple layers embodying the principles and concepts of the present invention and generally designated by thereference numeral46 inFIGS. 4 and 5 will be described.
• In the embodiment illustrated inFIG. 4, theinsole18 is again formed as part of the upper14. Themidsole46 includes three layers, atop layer48, amiddle layer50 and abottom layer52. Themidsole46, as shown inFIGS. 4-6, has anupper surface54 and abottom surface56. Thetop layer48 of themidsole46 can be attached via conventional means to either an insole such asinsole18, or to the upper14, while thebottom surface56 ofbottom layer52 is attached to theoutsole22 using a conventional method of attachment.
• Top layer48 of themidsole46 is positioned below theinsole18 and above themiddle layer50 of themidsole46. The specific material of thetop layer48 may be chosen depending upon the nature and type of shoe in which it will be used.Top layer48 may be made from a variety of materials including, but not limited to, molded Polyurethane (PU), Polyvinyl Chloride (PVC), Thermoplastic Urethane (TPU), Thermoplastic Rubber (TPR), vulcanized rubber, EVA, rubberlon, or any other synthetic or natural material. The material forming thetop layer48 has a hardness factor greater than the middle andbottom layers50 and52 and is generally in the range of 60-90° Asker C hardness. The material and hardness/softness ranges selected will be determined by the type of footwear onto which midsole46 is intended to be placed.
• Lying underneathtop layer48 of themidsole46 is amiddle layer50 having anupper surface58 and abottom surface60.Middle layer50 of themidsole46 is positioned below thetop layer48 and above thebottom layer52 of themidsole46. The specific material of themiddle layer50 may be chosen depending upon the nature and type of shoe in which it will be used.Middle layer50 may be made from a variety of materials including, but not limited to, molded Polyurethane (PU), Polyvinyl Chloride (PVC), Thermoplastic Urethane (TPU), Thermoplastic Rubber (TPR), vulcanized rubber, EVA, rubberlon, or any other synthetic or natural material. The material forming themiddle layer50 has a hardness factor lesser than the top andbottom layers48 and52 and is generally in the range of 20-50° Asker C hardness, and preferably in the range of 20-40° Asker C hardness. The material and hardness/softness ranges selected will be determined by the type of footwear onto which midsole46 is intended to be placed.
• In the embodiment illustrated inFIGS. 4 and 5, themiddle layer50 extends across the entire length of thetop layer48. Theupper surface58 ofmiddle layer50 is attached to thebottom surface62 of thetop layer48 using a conventional method of attachment, such as adhesive, while thebottom surface60 of themiddle layer50 is attached to theupper surface64 of thebottom layer52 in the heel portion of the sole16 and to theupper surface66 of theoutsole22 in its remaining portion, namely, in the arch and forefoot areas.
• Thebottom layer52 of thepresent midsole46 is positioned below themiddle layer50 and above theoutsole22 and may be made from a variety of materials including, but not limited to, TPR. Theupper surface64 ofbottom layer52 is attached to thebottom surface60 of themiddle layer50 at the heel portion of the sole16 using a conventional method of attachment, such as adhesive, while thebottom surface56 of thebottom layer52 is attached to theupper surface66 of theoutsole22 in the heel portion of the sole16. In contrast, thebottom surface60 of themiddle layer50 is attached directly to theupper surface66 of theoutsole22 in the arch and forefoot areas of the sole16. Thebottom layer52 may further be secured to themiddle layer50 by utilizing male connection portions, projections, flanges orcomponents68 associated with thetop surface64 of thebottom layer52 as best shown inFIG. 6, whichportions68 mate with and engage corresponding female connection portions, cut-outs, cavities, notches orcomponents70 associated with themiddle layer50 as best shown inFIGS. 4 and 5. Theflanges68 mate with and engage the cut-outs70 when thebottom layer52 is attached to themiddle layer58. Regardless of the type of material used for thebottom layer52, thebottom layer52 is softer than thetop layer48 and is generally of a hardness in the range of 20-65° Asker C hardness, and preferably in the range of 40-60° Asker C hardness.
• In the particular embodiment illustrated inFIGS. 4,5 and6, thebottom layer52 ofmidsole46 is utilized to provide additional shock absorption to the wearer of theshoe12 in that thebottom layer52 acts as a shock absorption means to further absorb shock to the heel of the wearer as the heel portion of theshoe12 strikes the ground during a normal gait. It is also recognized and anticipated that in some embodiments, thebottom layer52 of themidsole46 may extend beyond the heel portion of the sole16 to include the arch area and/or forefoot area of the sole16 as well, or portions thereof. Regardless of the types of materials used for each of the threeseparate layers48,50 and52 associated with thepresent midsole construction46, improved shock absorption is achieved in this particular midsole construction due to the fact that thetop layer48 of themidsole46 is harder than themiddle layer50 andbottom layer52 of themidsole46 and thebottom layer52 is harder than themiddle layer50 of themidsole56. Stated another way, thebottom layer52 is softer than thetop layer48, but is harder than themiddle layer50 of themidsole construction46. This arrangement of layers and hardness factors provides for improved shock absorption to the wearer of theshoe12.
• Thus, there have been shown and described two embodiments of a novel invention. As is evident from the foregoing description, certain aspects of the present invention are not limited by the particular details of the examples illustrated herein, and it is therefore contemplated that other modifications and applications, or equivalents thereof, will occur to those skilled in the art. The terms “having” and “including” and similar terms as used in the foregoing specification are used in the sense of “optional” or “may include” and not as “required”. Many changes, modifications, variations and other uses and applications of the present invention will, however, become apparent to those skilled in the art after considering this specification and the accompanying drawings. All such changes, modifications, variations and other uses and applications which do not depart from the spirit and scope of the invention are deemed to be covered by the invention which is limited only by the claims which follow.

Claims (34)

1. A midsole of a shoe comprising:

a top layer;

a middle layer extending at least partially across the length of said top layer and attachable to said top layer; and

a bottom layer attachable to said middle layer along at least a portion of its length;

said top layer having a hardness greater than said middle and bottom layers, and said middle layer having a hardness greater than said bottom layer.

2. The midsole ofclaim 1 wherein said middle layer extends across the heel portion of said top and bottom layers.

3. The midsole ofclaim 2 wherein the heel portion of said bottom layer is attached to said middle layer and the remaining portion of said bottom layer is attached to said top layer.

4. The midsole ofclaim 1 wherein said top layer includes male connecting portions and said middle layer includes corresponding female connecting portions, said male connecting portions engaging said female connecting portions when said middle layer is attached to said top layer.

5. The midsole ofclaim 1 wherein said top layer is made of a polyurethane material.

6. The midsole ofclaim 1 wherein said middle layer is made of a thermoplastic rubber material.

7. The midsole ofclaim 1 wherein said bottom layer is made of a polyurethane material.

8. The midsole ofclaim 1 wherein said top layer has a hardness in the range of 60-90° Asker C hardness.

9. The midsole ofclaim 1 wherein said middle layer has a hardness in the range of 20-65° Asker C hardness.

10. The midsole ofclaim 1 wherein said bottom layer has a hardness in the range of 20-50° Asker C hardness.

11. The midsole ofclaim 1 further including an outsole attachable to the bottom layer of said midsole.

12. A midsole of a shoe comprising:

a top layer made of a material having a hardness in the range of 60-90° Asker C hardness;

a middle layer extending at least partially across the length of said top layer and attachable to said top layer, said middle layer being made of a material having a hardness in the range of 40-60° Asker C hardness; and

a bottom layer attachable to said middle layer along at least a portion of its length, said bottom layer being made of a material having a hardness in the range of 20-40° Asker C hardness.

13. The midsole ofclaim 12 wherein said top layer is made of a polyurethane material.

14. The midsole ofclaim 12 wherein said middle layer is made of a thermoplastic rubber material.

15. The midsole ofclaim 12 wherein said bottom layer is made of a polyurethane material.

16. The midsole ofclaim 12 wherein said middle layer extends substantially across the length of said top layer.

17. A midsole of a shoe comprising:

a top layer;

a middle layer attachable to said top layer; and

a bottom layer extending at least partially across the length of said middle layer and attachable to said middle layer;

said top layer having a hardness greater than said middle and bottom layers, and said bottom layer have a hardness greater than said middle layer.

18. The midsole ofclaim 17 wherein said bottom layer extends across the heel portion of said middle layer.

19. The midsole ofclaim 18 wherein said bottom layer is attached to the heel portion of said middle layer.

20. The midsole ofclaim 17 wherein said middle layer includes female connecting portions and said bottom layer includes corresponding male connecting portions, said male connecting portions engaging said female connecting portions when said bottom layer is attached to said middle layer.

21. The midsole ofclaim 17 wherein said top layer is made of a polyurethane material.

22. The midsole ofclaim 17 wherein said middle layer is made of a polyurethane material.

23. The midsole ofclaim 17 wherein said bottom layer is made of a thermoplastic rubber material.

24. The midsole ofclaim 17 wherein said top layer has a hardness in the range of 60-90° Asker C hardness.

25. The midsole ofclaim 17 wherein said middle layer has a hardness in the range of 20-50° Asker C hardness.

26. The midsole ofclaim 17 wherein said bottom layer has a hardness in the range of 20-65° Asker C hardness.

27. The midsole ofclaim 17 further including an outsole attachable to the bottom layer and to a portion of the middle layer of said midsole.

28. A midsole of a shoe comprising:

a top layer made of a material having a hardness in the range of 60-90° Asker C hardness;

a middle layer attachable to said top layer and being made of a material having a hardness in the range of 20-40° Asker C hardness; and

a bottom layer attachable to said middle layer along at least a portion of its length, said bottom layer being made of a material having a hardness in the range of 40-60° Asker C hardness.

29. The midsole ofclaim 28 wherein said top layer is made of a polyurethane material.

30. The midsole ofclaim 28 wherein said middle layer is made of a polyurethane material.

31. The midsole ofclaim 28 wherein said bottom layer is made of a thermoplastic rubber material.

32. The midsole ofclaim 28 wherein said bottom layer extends substantially across the heel area of said middle layer.

33. The midsole ofclaim 28 wherein said middle layer includes connecting portions which are cooperatively engageable with corresponding connecting portions associated with said bottom layer when said bottom layer is attached to said middle layer.

34. The midsole ofclaim 33 wherein said bottom layer includes a pair of flanges which are cooperatively receivable within a corresponding pair of cut-offs associated with said middle layer.

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