Footwear sole assembly having spring mechanism
A sole assembly which includes a heel cradle configured to cradle a heel of a human foot when the human foot is rested within the heel cradle, a rigid upper plate including a first part connected to the heel cradle and a second part located farther from the heel cradle than is the first part, a lower plate including a first part of which is connected to the first part of the upper plate and including a second part which is connected to the second part of the upper plate, an oblong gap located between the upper plate and lower plate and between the first and second parts of the upper and lower plates. A sole assembly including an upper plate and a lower plate stiffer than the upper plate and attached to the upper plate so as to form an oblong gap. Also, a shoe including the sole assembly.
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1. Field of the Invention
The present invention relates to a device that supports a person's foot, and more specifically, to a shoe sole assembly having a spring mechanism for storing and releasing mechanical energy during the gait cycle.
2. Discussion of the Background
Footwear has often incorporated various methods of absorbing impact energy generated while a person walks or runs. Specifically, sponges or cushion materials are often used to absorb and dissipate energy throughout the wearer's gait cycle. However, in order to achieve sufficient cushioning, a large amount of cushioning material that substantially covers the entire plantar region of the shoe may be necessary. This creates a thick and heavy sole structure that adds weight to the shoe and prevents air flow to the plantar region of the wearer's foot. Cushion material may also become compacted over time and lose its cushioning effect, and does very little to store energy for use during the gait cycle.
Shoe makers have also created “through-holes” in the cushion material that extend from the lateral to medial sides of the shoe sole in order to reduce the weight of the shoe. However, as these conventional through-holes are typically mere vacancies created in the cushion material, they do not provide effective air flow to the plantar region of the wearer's foot. Moreover, conventional through-holes do not provide a structure for effectively storing mechanical energy.
Various spring elements have been used in footwear in an attempt to store impact energy for use during the gait cycle. For example, U.S. Pat. No. 6,449,878 discloses a spring assembly including a first spring element that extends over a large area of the shoe sole, and a second spring element attached to the first element in a midfoot region but spaced from and opposing the first element in a heel region of the shoe. The opposing first and second spring elements form a tension spring in the heel region of the shoe. However, this spring assembly is complex and requires large and highly resilient components that are too heavy to be of practical use for most shoes, particularly athletic shoes.
While simple and light-weight plastic-type assemblies have been implemented into footwear, these structures have generally been used to provide rigidity to certain regions of the sole and cannot efficiently store and release energy during the gait cycle. For example, U.S. Patent Publication 2003/0005600A1 discloses a plastic shank member embedded in a midfoot region of a shoe sole. The shank member is a substantially rigid sheet of material closed to form an oblong cross sectional shape. Placement of the shank member in the midfoot region of the midsole provides greater rigidity to this area of the midsole so that the forefoot of the midsole is more bendable. However, the shank is not disclosed as a spring element for storing and releasing energy during gait.
Furthermore, the present inventors have recognized that when any type of energy storage device is implemented in footwear, foot placement within the shoe during contact with the ground is important to realizing a spring effect. Moreover, if the foot is improperly placed relative to the energy storage device, the device may interfere with the natural sequence of pressure distribution of the foot during the footstep, thus resulting in foot discomfort. For example, in the heel area, the heel of the foot tends to break contact or at least reduce pressure on the heel portion of the sole of the shoe when the foot is lifted. Accordingly, the heel of the foot may drift within the shoe and not impact the sole of the shoe in the optimum location for cushion effect and energy storage. Conventional shoes have not recognized this importance of heel placement, and thus have not provided comfortable and efficient energy storage mechanisms.
SUMMARY OF THE INVENTIONAccordingly, one object of the present invention is to address at least some of the above described and/or other problems of conventional footwear.
Another object of the present invention is to provide a simple, light-weight footwear spring element for effectively storing and releasing energy during the gait cycle.
Yet another object of the present invention is to provide a footwear mechanism for effectively positioning the wearer's heel in relation to a sole spring element in order to enhance efficient storage of energy in the spring at impact. Any of these and/or other objects can be provided by a sole assembly according to the present invention.
According to one aspect of the present invention, a sole assembly is disclosed including: a heel cradle configured to cradle a heel of a human foot when the human foot is rested within the heel cradle, a rigid upper plate including a first part connected to the heel cradle and a second part located farther from the heel cradle than is the first part, a lower plate including a first part which is connected to the first part of the upper plate and including a second part which is connected to the second part of the upper plate, an oblong gap located between the upper plate and lower plate and between the first and second parts of the upper and lower plates shaped such that a gap dimension between the upper and lower plates in a first direction, measured from the first part of the upper plate to the second part of the upper plate, is greater than a gap dimension between the upper and lower plates in a second direction which is perpendicular to the first direction.
According to another aspect of the present invention, a shoe is disclosed including: an upper portion; and a sole assembly including, a heel cradle configured to cradle a heel of a human foot when the human foot is rested within the heel cradle, a rigid upper plate including a first part connected to the heel cradle and a second part located farther from the heel cradle than is the first part, a lower plate including a first part which is connected to the first part of the upper plate and including a second part which is connected to the second part of the upper plate, an oblong gap located between the upper plate and lower plate and between the first and second parts of the upper and lower plates shaped such that a gap dimension between the upper and lower plates in a first direction, measured from the first part of the upper plate to the second part of the upper plate, is greater than a gap dimension between the upper and lower plates in a second direction which is perpendicular to the first direction.
According to another aspect of the invention, a sole assembly is disclosed including: an outsole located on a side of the sole assembly and configured to support the sole assembly, a cushion material located next to the outsole, a means for cradling a heel of a human foot when the human foot is rested within the means for cradling, and a means for storing energy generated during walking connected to the means for cradling.
According to another aspect of the invention, a sole assembly is disclosed including: a rigid upper plate including a first part and a second part and having a first stiffness, a lower plate having a second stiffness greater than the first stiffness and including a first part which is connected to the first part of the upper plate and including a second part which is connected to the second part of the upper plate, an oblong gap located between the upper plate and lower plate and between the first and second parts of the upper and lower plates shaped such that a gap dimension between the upper and lower plates in a first direction, measured from the first part of the upper plate to the second part of the upper plate, is greater than a gap dimension between the upper and lower plates in a second direction which is perpendicular to the first direction.
BRIEF DESCRIPTION OF THE DRAWINGSA more complete appreciation of the invention and many of the attendant advantages thereof will be readily obtained as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings, wherein:
Referring now to the drawings, wherein like reference numerals designate identical or corresponding parts throughout the several views,
In the embodiment of
In the embodiment of
In the embodiment of
One benefit of using carbon fiber in the plates, especially the lower plate 4, is that because the carbon fiber is very strong and stiff, the lower plate 4 can provide the desired spring effect with a reduced thickness relative to other materials. Thus, the vertical dimension of gap 11 is increased without increasing the overall height of the sole assembly 2. This increase allows a greater range of travel between the upper plate 3 and the lower plate 4 within a given overall height of the sole assembly 2. In other words, with one or both plates made of a high stiffness material such as carbon fiber, the range of travel between the plates can be maintained while the sole assembly can be made shorter in height than would be possible with other materials.
In the embodiment of
As best seen in
The addition of the heel cradle 5 can enhance the effect of the spring mechanism by improving a position of the wearer's heel as the heel of the foot lifts and descends during walking or running. The present inventors have realized that by consistently centering the heel of the foot in relation to the sole assembled, the upper plate 3 and lower plate 4 more efficiently store and release energy during gait. Furthermore, proper positioning of the heel allows the sole assembly 2 to smoothly accommodate the natural gait of the wearer and to provide support where needed. To achieve proper positioning of the heel of the foot, the heel cradle 5 is typically added to the shoe on the outside of the upper 1 as shown in
Further in the non-limiting embodiment shown in
As shown in
As seen in
The rear cushion 6 is coupled to the front cushion material 7 to provide a planar surface for attaching the outsole 8. The outsole 8 is preferably implemented as a layer of deformable rubber material that contacts the ground when the shoe is in use, and preferably includes treads that are designed to grip a variety of ground surfaces. As seen in
The present inventors have discovered that the sole assembly of the exemplary embodiment of
Specifically, prior to heel impact of the gait cycle when the heel is not in contact with the ground, the heel cradle 5 can provide lateral support for the heel and maintain a substantially center position of the heel on the sole assembly 2. A downward force created from heel contact to the midstance portion of the gait cycle is applied to the upper plate 3. This causes the upper plate 3 to deflect in elastic deformation downward toward the lower plate 4, thus storing the energy of the applied load. This stored energy is then released during the windlass phase of the gait cycle when the foot locks into place and moves from midstance to toe off. This creates a natural propulsion sensation to the wearer. The absorbing material functions to absorb and disperse shock forces in order to cushion the foot during this gait cycle, and can further dampen the spring effect of the spring element to provide a smoother feel.
The tread portion 8 includes a plurality of small holes 8a therein at a forefoot region of the sole assembly, and a larger hole 8d extending from the heel to midfoot region of the sole assembly 2. In the embodiment of
As also by a comparison of
Further shown in
The sole assembly of
Such asymmetrical levels of stiffness can reduce foot pronation. For example, human feet naturally rotate or roll inward during walking, i.e., the feet pronate. Over-pronation occurs when the arch of a human foot collapses upon weight bearing. Problems associated with over-pronation include soft-tissue inflammation and joint stress. To avoid over-pronation, shoes with augmented arch supports have been designed. However, the augmentation may undesirably add to the overall weight and height of the shoe. Additionally, as the augmentation is typically designed merely to prevent collapse of the arch of the foot, the augmentation does not efficiently store energy during walking or running. Thus, rather than augmenting the arch of a shoe with thicker padding which in turn would increase the weight and height of the shoe, a particular part of the foot such as, for example, the arch area of the foot, may be preferentially supported by altering the stiffness characteristics of the plates, either by changing plate geometry or by changing materials.
Various methods of stiffening particular portions of the plates exist. If the stiffness of the plate depends largely on the number of fibers present in the material, such as it typically does with fiber-glass or carbon fiber materials, the density of the fibers in a part of the plate may be increased or reduced during manufacture to affect the stiffness in a particular area. In yet another non-limiting embodiment, the chemical composition of the plate may be altered in various parts such that the stiffness changes.
Further, the thickness of the plate 40 may be increased on the medial side 46. As the stiffness of a cross-section of a plate is proportional to the cube of the thickness of the plate, even a small change in the thickness of the plate will have a large affect on the overall stiffness of the plate. Thus, grooves, ribs, and plates with gradually varying thicknesses may be used to affect the localized stiffness of the upper plate 3 or lower plate 4 or both. Still further, the medial side may be asymmetrical in shape as shown by the phantom wing extension 50 on the medial side, which may stiffen this area.
As shown in
In addition to asymmetry of the upper and lower plates themselves, the spring assembly may be positioned differently within the sole assembly to accommodate different foot types. For example, moving the spring mechanism forward or back may change a performance characteristic of the sole assembly. For example, a smaller system that is closer to the heel may work better for a mild overpronator. As another example, moving the system forward may create the best forefoot cushioning in a shoe. Still further, material and design variations may be implemented to provide a lower midsole height.
Clearly, numerous modifications and variations of the present invention are possible in light of the above teachings. It is therefore to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described herein.
Claims
1. A sole assembly comprising:
- a heel cradle configured to cradle a heel of a human foot when the human foot is rested within the heel cradle;
- an upper plate including a first part connected to the heel cradle and a second part located farther from the heel cradle than is the first part;
- a lower plate including a first part which is connected to the first part of the upper plate and including a second part which is connected to the second part of the upper plate;
- an oblong gap located between the upper plate and lower plate and between the first and second parts of the upper and lower plates shaped such that a gap dimension between the upper and lower plates in a first direction, measured from the first part of the upper plate to the second part of the upper plate, is greater than a gap dimension between the upper and lower plates in a second direction which is perpendicular to the first direction.
2. The sole assembly of claim 1, further comprising at least one insert attached to at least one of the upper plate and lower plate.
3. The sole assembly of claim 2, wherein the at least one insert is located in the lower plate.
4. The sole assembly of claim 3, wherein the at least one insert includes a material with a stiffness greater than a stiffness of a material comprising the lower plate.
5. The sole assembly of claim 4, wherein the at least one insert comprises at least one of carbon fiber and poly-paraphenylene terephthalamide.
6. The sole assembly of claim 4, wherein the insert is located nearer to a medial side of the lower plate than to a lateral side.
7. The sole assembly of claim 1, wherein the upper plate and lower plate are comprised of different materials.
8. The sole assembly of claim 7, wherein the lower plate comprises carbon fiber.
9. The sole assembly of claim 7, wherein the lower plate comprises poly-paraphenylene terephthalamide.
10. The sole assembly of claim 1, wherein the heel cradle comprises a different material than the upper plate.
11. The sole assembly of claim 1, wherein the heel cradle and upper plate are a continuous piece of material.
12. The sole assembly of claim 11, wherein the heel cradle is vented.
13. The sole assembly of claim 12, wherein the heel cradle is partially directly supported by the upper plate and partially directly supported by a cushion material.
14. The sole assembly of claim 1, wherein the upper plate is asymmetrical about a vertical plane that passes through a center of the heel cradle and a center of a toe of the sole assembly.
15. The sole assembly of claim 14, wherein the lower plate is asymmetrical about a vertical plane that passes through a center of the heel cradle and a center of a toe of the sole assembly.
16. The sole assembly of claim 15, wherein the lower plate has vertical protrusions that support walls of the heel cradle.
17. The sole assembly of claim 1, wherein the lower plate includes a cavity.
18. The sole assembly of claim 17, wherein the upper plate includes a cavity at least partially overlapping the cavity of the lower plate.
19. The sole assembly of claim 1, wherein a medial side of the lower plate is stiffer than a lateral side of the lower plate.
20. The sole assembly of claim 19, wherein a medial side of the upper plate is stiffer than a lateral side of the upper plate.
21. The sole assembly of claim 1, wherein the thickness of the upper plate varies from a portion of a medial side to a portion of a lateral side.
22. The sole assembly of claim 21, wherein the thickness of the lower plate varies from a portion of a medial side to a portion of a lateral side.
23. A shoe comprising:
- an upper portion; and
- a sole assembly including, a heel cradle configured to cradle a heel of a human foot when the human foot is rested within the heel cradle; an upper plate including a first part connected to the heel cradle and a second part located farther from the heel cradle than is the first part; a lower plate including a first part which is connected to the first part of the upper plate and including a second part which is connected to the second part of the upper plate; an oblong gap located between the upper plate and lower plate and between the first and second parts of the upper and lower plates shaped such that a gap dimension between the upper and lower plates in a first direction, measured from the first part of the upper plate to the second part of the upper plate, is greater than a gap dimension between the upper and lower plates in a second direction which is perpendicular to the first direction.
24. A sole assembly comprising:
- an outsole located on a side of the sole assembly and configured to support the sole assembly;
- a cushion material located next to the outsole,
- means for cradling a heel of a human foot when the human foot is rested within the means for cradling; and
- means for storing energy generated during walking connected to the means for cradling.
25. A sole assembly comprising:
- an upper plate including a first part and a second part and having a first stiffness;
- a lower plate having a second stiffness greater than the first stiffness and including a first part which is connected to the first part of the upper plate and including a second part which is connected to the second part of the upper plate,
- an oblong gap located between the upper plate and lower plate and between the first and second parts of the upper and lower plates shaped such that a gap dimension between the upper and lower plates in a first direction, measured from the first part of the upper plate to the second part of the upper plate, is greater than a gap dimension between the upper and lower plates in a second direction which is perpendicular to the first direction.
26. The sole assembly of claim 25, wherein the upper plate and lower plate are comprised of different materials.
27. The sole assembly of claim 26, wherein the upper plate comprises TPU and the lower plate comprises carbon fiber.
28. The sole assembly of claim 26, wherein the upper plate comprises TPU and the lower plate comprises poly-paraphenylene terephthalamide.
29. The sole assembly of claim 26, wherein the upper plate has a greater thickness in the vertical direction than the lower plate.
30. The sole assembly of claim 29, wherein the thickness of the upper plate is 3 mm and the thickness of the lower plate is 1.5 mm.
31. The sole assembly of claim 26, wherein the lower plate includes an insert.
32. The sole assembly of claim 31, wherein the insert is disposed on a medial side of the lower plate and comprises a material having a different stiffness than material of the lower plate.
33. The sole assembly of claim 25, wherein the upper plate and lower plate include wings projecting toward a toe region of the sole assembly.
34. The sole assembly of claim 33, wherein a wing on a medial side of the upper and lower plates is longer than a wing on a lateral side.
35. The sole assembly of claim 25, wherein the lower plate includes a cavity.
36. The sole assembly of claim 35, wherein the upper plate includes a cavity at least partially overlapping the cavity of the lower plate.
Type: Application
Filed: Nov 10, 2005
Publication Date: May 10, 2007
Applicant: Fila Luxembourg S.A.R.L. (Grand Duche du Luxembourg)
Inventors: Chris Brewer (Baltimore, MD), Olivier Henrichot (New York, NY)
Application Number: 11/270,526
International Classification: A43B 13/00 (20060101);