Patent Grant
7946059
This application claims priority under 35 U.S.C. §119 of French Patent Application No. 06.03383, filed on Apr. 14, 2006, the disclosure of which is hereby incorporated by reference thereto in its entirety.
1. Field of the Invention
The invention relates to a shock-absorbing system for footwear, particularly sports footwear, such as walking shoes, running shoes, and the like. More particularly, the invention relates to an article of footwear having such system, such system comprising a shock-absorbing bottom assembly.
2. Description of Background and Relevant Information
There are a large number of shock-absorbing, or damping, systems for sports footwear, which are adapted to damp the reactive forces coming from the ground during the course of walking or running, or during other movement.
These damping devices are conventionally designed for damping the reactive forces that occur mainly perpendicular with respect to the surface of the ground, that is, primarily vertically directed forces. Indeed, the reactive forces occurring in this direction are conventionally considered as being the most substantial. Therefore, these vertical reactive forces are generally damped by merely providing a foam block generally made of EVA and which is vertically deformable. Other means using pockets filled with fluid or gas are also known.
Focus has been directed more recently to those ground reactive forces that occur in the plane of the ground, rather than vertically, which will be referred to hereinafter as the horizontal plane.
Depending upon the type of sport practiced, such horizontal forces are more or less substantial. For example, in sports such as tennis or basketball, where a number of movements are lateral, the reactive forces occurring along the ground plane can be very high.
The horizontal reactive forces that occur when running on asphalt are higher, because the high coefficient of friction of asphalt stops any relative horizontal movement of the sole with respect to the ground, which is not the case when running on looser ground, on which ground/sole relative movements can occur.
This finding has led to new footwear constructions, in which the sole damping devices are designed so as to permit a certain relative movement of the sole with respect to the ground, and/or shearing movements within the sole itself, in order to absorb the forces occurring in an essentially horizontal plane and to reproduce the effects of running on loose ground.
Such constructions are known, for example, from the documents U.S. Pat. Nos. 6,487,796, 5,343,639, 6,962,008, EP 1 402 795, and U.S. Pat. No. 5,224,810.
These documents generally teach damping only in the horizontal plane.
The documents WO 98/07343 and U.S. Pat. No. 6,266,897 disclose a construction in which pocket-like elements filled with fluid can deform in all three directions, that is, in the horizontal plane as well as in the vertical direction.
The drawback of such a construction is that deformations in any of the directions are uniform. Therefore, it is not possible to distinguish/dissociate the vertical damping from the horizontal damping.
Another problem common to all of the damping devices is in reconciling damping and stability of the foot on the ground, such as the “grip” the shoe has relative to the ground, these functions being more or less incompatible.
The present invention remedies the drawbacks of the prior art and provides an improved damping, or shock-absorption, device.
More particularly, the invention provides a device for damping in three different directions, that is, along a horizontal plane as well as along a vertical direction.
Still further, the invention provides a damping device that has good grip and/or “road stability”.
According to a particular description, the invention includes an upper overlaying an outer bottom assembly, the outer bottom assembly including, in the area of the heel, at least two support elements made of a damping material and arranged on the lateral and medial sides, respectively, of the bottom assembly, each element extending vertically, substantially from an upper end up to a lower end of the outer bottom assembly, the support elements being deformable substantially independently of one another, and the outer bottom assembly including an elastically deformable element having an upper portion that extends transversely with respect to the bottom assembly and which covers the upper end of each of the support elements, and at least two legs extending laterally and medially, respectively, and externally surrounding each of the support elements substantially over their entire height.
This construction enables damping in all directions while ensuring that the footwear has good stability and grip.
Indeed, in the case of an essentially vertical force, the support elements are compressed and absorb the energy thus generated. Because they are independent and not connected at their lower end by a common walking sole, as is the case in the known devices, the support elements also move apart from one another with respect to the longitudinal axis of the footwear and thus increase the support polygon. As a result, the footwear stability is necessarily increased.
The invention will be better understood, and other characteristics thereof will become apparent from the description that follows, with reference to the annexed schematic drawings showing several embodiments, by way of non-limiting examples, and in which:
a is a side view of
With the expression “outer bottom assembly” or “bottom assembly,” reference is made herein to an assembly of the bottom parts of an article of footwear, i.e., those parts which are positioned beneath the upper, as the article of footwear is worn. In this regard, the outer bottom assembly 10 does not include sole portions such as the insole, sock, Strobel sole, or lasting insole, which can be directly connected to the upper 2 and/or arranged therein. The upper 2 is fixed to the outer bottom assembly 10 in any known manner, such as by means of glue, stitching, staples, or various expedients known to those skilled in the art.
As shown more particularly in
The upper damping layer 20 extends over the entire length of the bottom assembly 10, or substantially over the entire length, that is, from the rear end to the front end thereof, and includes a front portion 21 and a rear portion 22, respectively, having a uniform thickness, or substantially uniform thickness. The front portion 21 is thicker than the rear portion 22, with a thickness, for example, on the order of 4 millimeters (mm) to 15 mm. The rear portion 22 has a thickness, for example, on the order of 3 mm to 10 mm. In the example shown, the front portion 21 is ended at the rear by a chevron-shaped portion 23, which forms a step in relation to the rear portion 22, and the function of which is explained below. Alternatively, any shape other than the chevron shape 23, such as a wave shape, e.g., can be provided. The upper portion 24 of the upper damping layer 20 is substantially flat/planar or adapted to the shape of the upper. It can also have vertical, or substantially vertical, edges or sides 25 adapted to rise along the upper 2. These edges 25 are higher in the rear zone, especially in the heel zone, and the elastically deformable element 30 includes in the heel area a bowl-shaped portion 31, that is, a portion having a relatively flat bottom 31a, or base, that assumes the shape of the upper damping layer 20. In this regard, edges/sides 31b extend upwardly from the base 31a, rising along the upper or the edges 25 of the upper damping layer 20. As shown in
Each leg 34, 35, 36 extends from the rear bowl-shaped portion 31 to the bottom and has a free end in the form of a return 34a, 35a, 36a, respectively, adapted to be inserted between the damping support elements 40 and the contact layer 50. These returns 34a, 35a, 36a, are essentially adapted to ensure that the legs 34, 35, 36 and the contact layer 50, as well as the support elements 40 adhere properly to one another. The returns can be omitted within the scope of the invention, whereby each of the legs would extend downwardly, terminating with the respective support elements 40 at a downwardly facing free end. In either case, the free end of the legs would be positioned proximate the lowermost surfaces of the support elements.
In the example shown, the legs 34, 35, 36 are relatively planar/flat and, in the cross section of the bottom assembly, they are slightly inclined in relation to the vertical direction V (see
Further, as shown in
The elastically deformable element is extended forward by two planar/flat arms 37, the function of which is explained below. The element 30 is made of a relatively rigid and elastic material having a Young's Modulus greater than 40 MPa. It can be made of a synthetic or composite material, such as TPU, PE, reinforced or non-reinforced polyamide, elastomeric polymer (Hytrel®, e.g.), PEBA, carbon/resin fiber-base composite, or other material.
The upper damping layer 20 can be made of EVA or PU foam, with a hardness greater than 20 Asker C, or substantially greater than 20 Asker C.
The damping support elements 40 comprise blocks of damping materials, arranged between the elastically deformable element 30 and the contact layer 50.
In the first embodiment, the support elements 40 are independent and as many as three, namely, a medial block 41 arranged on a medial side of the shoe, two lateral blocks 42, 43 arranged on the lateral side of the shoe. In other words, the support element 41 extends at least on the medial side of a vertical longitudinal median plane and the support elements 42, 43 extend at least on the lateral side of a vertical longitudinal median plane, although the support element 43 extends to or beyond the vertical longitudinal median plane. The medial block 41 is slightly arched so as to follow the contour of the bottom assembly and extends substantially over the entire length of the heel zone of the bottom assembly. This medial block 41 cooperates with the two medial legs 35 of the elastically deformable element 30. The forwardmost lateral block 42 has a substantially paralellepipedic shape and cooperates with only one lateral leg 34 of the elastically deformable element 30. The rearmost lateral block 43 extends on the lateral side and over a portion of the rear of the heel and cooperates with a lateral leg 34 and a rear 36 leg, respectively, of the elastically deformable element. The number of legs could be different for each block, according to the invention.
The lateral block 43 also has the shape of an arc-of-a-circle, or substantially so, so as to assume the contour of the heel.
In the illustrated embodiment, the lateral block 43 has substantially the same length as the medial block 41, but could have a different length. For example, the medial block 41 could be longer. The two lateral blocks 42, 43 are separated by a slit-shaped space 46 that is substantially perpendicular to the edge of the bottom assembly, whereas the medial and lateral blocks 41, 43 are separated by a slit-shaped space 47 that is also substantially perpendicular to the edge or contour of the bottom assembly in the zone considered.
The support blocks 41, 42, 43 are assembled to the elastically deformable element, independently of one another, by their upper ends 41a, 42a, 43a, respectively. In the example shown, the medial block 41 is extended toward the front of the shoe, i.e., beyond the plantar arch, by a slightly thinner damping layer 44 ended by a triangular or chevron-shaped 44d portion that is complementary of that of the front portion 21 of the upper damping layer 20, so as to ensure the shape these two layers fit one another. Alternatively, other forms can be used according to the invention. The thickness of the layer 44 corresponds to that of the step 23 of the chevron. In practice, the blocks 41, 42, 43 are made of elastomerized EVA foam, or PU foam having a 20 Asker C hardness. Indeed, the behavior of such foams is concurrently damping and elastic. As the case may be, more damping foams, such as non-elastomerized EVA foams, can be provided as alternatives within the scope of the invention. In the example shown, the blocks have a vertical thickness ranging from 10 mm to 30 mm, for example, such as 20 mm, or on the order of 20 mm, or a thickness within any range within said range.
The elements 30 and 40 are pre-assembled into a subassembly 60 prior to assembly to the damping layer 20 to form the bottom assembly 10. The arms 37 are housed in recesses 27 of the layer 20 to consolidate the assembly.
As also clearly shown in
Depending upon the embodiment, these recesses could also be omitted.
The contact layer 50 is constituted of rear medial 51, rear lateral 52, 53, and front 54 elements, respectively, adapted to be fixed to the lower ends 41b, 42b, 43b, 44b, respectively, of the support blocks 41, 42, 42, 44, respectively, and of the damping layers 44 and 21, respectively.
The contact layer 50 is made of a wear-resisting material with adherence properties, such as rubber, TPU, or non-abrasive EVA foam, e.g., the latter two materials having the advantage of being lighter than rubber. As the case may be, and depending upon the material used for the support blocks and/or the damping layer, this contact layer 50 can be reduced, or even eliminated.
The combination of an elastically deformable but structurally rigid element 30 and damping support blocks 40 makes it possible to ensure a good damping in all directions, that is, a three-dimensional damping, since the damping blocks 40 are independent, while guaranteeing the stability of the assembly due to the elastic element 30. Furthermore, due to the various shapes of the blocks 41, 42, 43, and to the various numbers/shapes of legs per associated block, the damping characteristics of the blocks can be dissociated between the blocks, on the one hand, and between the vertical and horizontal directions, on the other hand. The functioning of the assembly is shown more particularly in
When a force “F” is applied to the bottom assembly in a substantially vertical direction, such as during walking or running, as shown in
As soon as the application of force “F” is discontinued, the elastically deformable element 30 exerts a return force and tends to bring the support blocks 40 back to the initial position shown in
Because the support blocks 40 are independent, they can therefore deform independently of one another in order to adapt to the foot movement or to the terrain configuration. Thus, in
In this embodiment, a primary difference, relative to the embodiment described above, resides in the fact that the damping support blocks 141, 142, 143 are connected to one another by a bridge or wall 147 of material. Because the wall 147 is very thin, on the order of 3 mm to 10 mm, relative to the support blocks 141, 142, 143, the latter are always free to move independently of one another. However, the fact that they are connected makes it easier to assemble them.
Furthermore, when a force “F” is exerted on the outer bottom assembly shown in
To enable this elastic return effect of the wall 147, the wall is not adhered to the elastically deformable element 130. Instead, it is separated therefrom by a cavity or space 148.
Another difference between the two aforementioned embodiments is the that the damping blocks 141, 142, 143, 144 are formed as a unitary element.
Finally, the medial support block 141 is made of a material that is similar to that of the remainder of the assembly 140, such as EVA foam, for example, but with a greater hardness, such as between 50 and 65 Asker C, for example. It is also extended to the portion 144 by a portion 144a having the same hardness. Alternatively, the support block 141 can be made of a different material, with the goal of being slightly harder (therefore less damping than the other blocks). This function is also linked to the pronator/supinator type of the shoe.
In the embodiment shown in
In this case, the damping support elements 241, 242, 243 of the outer bottom assembly are also grouped in a single block 240. Compared to the previous embodiments, where the element 40, 140 stops shortly after the plantar arch, the element 240 here extends up to the area of the shoe corresponding to the metatarsophalangeal articulation zone of the wearer's foot, and is therefore longer.
The extra thick portion 221 of the damping layer 220 is consequently reduced and only extends from the front of the sole to the metatarsophalangeal articulation zone (defined in this case by the step 223). Furthermore, the elastically deformable element 230 has two elongated horizontal arms 237 at the front, which form a sort of fork.
The elongated arms 237, therefore, extend into the metatarsophalangeal articulation zone demarcated by the limits 223, 244d, and make it possible to provide the bottom assembly, in its front zone, with an additional elastic restoration. Furthermore, these arms 237 each include a leg 238 similar to the legs 234, 235, 236, and extend substantially vertically along the front portion 244 of the support block 240.
The vertical legs 238, as is the case with the legs 234, 235, 236, increase the stability of the bottom assembly.
In the illustrated embodiment, the arms 237 and lugs 238 of the elastically deformable element 230 are housed in associated recesses 244e, 244f of the support block, these recesses having complementary shapes and being arranged on the upper surface and the sides, respectively, of the front portion 244 of the support block 240.
In these various embodiments, the bottom assembly includes at least two support elements, but additional return/stabilization arrangements are also provided.
In the embodiment of
As in the embodiment of
In order to reinforce the elastic return effect, the contact layer 350 is also provided so as to connect the various support blocks 341, 342, 343 and, therefore, includes a material wall 355 connecting these various elements in the area of their lower end. Because the contact layer 350 is made of a very elastic material, such as rubber or any elastomerized material, it enables an advantageous effect of elastic return of the bottom assembly toward the original position.
Such a construction enables an additional stabilizing effect. In practice, this rubber wall 355 makes it possible to avoid up to 5 mm of residual spacing of the blocks after the return to the original position.
In other words, almost any residual deformation that would result in the spacing apart of the blocks is avoided. In practice, a residual deformation of 5 mm to 8 mm is avoided over the width of the sole.
The rubber wall 355 (or any other material) can be provided individually, i.e., independent of the wall 347.
In this case, the space 460 between two support elements 441, 443, 442 is filled with a material 461 such as EVA, PU, or gel, adapted to avoid having a hole behind the material wall 455. The space 460 can be filled by localized extensions, with a smaller cross section, of the material of the support elements 441, 442, 443, as defined, for example, by the arms 355a, 355b, 355c in
In the embodiment of
However, a cavity 548 is arranged between the elastically deformable element 530 and the support elements 541, 543, 542 so as to keep the support elements independent, and a material wall 547 made of the same material as the support elements 542, 543, 541, is provided between the latter.
In the embodiment of
In
In
The configuration of
In the various embodiments, the number of arms 355a, 355b, 355c or 355d, 355e can be modified and, for example, can be as many as four or more, or less.
The present invention is not limited to the various embodiments described hereinabove by way of non-limiting examples, but encompasses all similar or equivalent embodiments.
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