US 20110078923 A1
The walking device has a shoe bottom with a midsole. A soft heel part is arranged in a recess of the midsole and the outsole has a form that is rounded convexly in the walking direction. The reinforcing element, forming an insole, is arranged on the upper surface of the midsole and fastened to it. In the production of the walking device, the upper is joined to the reinforcing element to form a structural unit, which is then mounted on the midsole, for example by adhesive bonding.
1. A walking device with a shoe bottom, which has a midsole, extending over a heel region, a midfoot region and a ball and toe region, a soft heel part, arranged in a recess of the midsole, and an outsole, which is kept—in the unloaded state—in a form that is rounded convexly in the walking direction by the midsole and the soft heel part, an upper, arranged on the shoe bottom, and a reinforcing element, which has such stability that the midsole is at least almost free from bending—with respect to loads during standing and walking—in its portion located above the soft heel part, wherein the reinforcing element, forming an insole, is arranged on an upper surface of the midsole, facing away from the outsole, and is fastened to said surface.
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The present invention relates to a walking device according to the preamble of patent claim 1.
Walking devices of this type are known by the name Masai Barefoot Technology, MBT for short, and also known under the Swiss Masai label. A characteristic feature of the MBT walking devices is a form of sole that is rounded convexly in the walking direction, with a soft heel part, known as the “Masai sensor”, inserted in a recess of a midsole. The midsole has a reinforcing element—known as a “shank”—integrated in it, which reinforces the midsole in such a way that it is substantially rigid even in the portion thereof that is above the soft heel part. On account of the bottom shoe structure of the MBT walking device, deliberately soft and made to act in a destabilizing manner for this reason, the foot loses the hold and support that is characteristic of physiological locomotion. This bottom structure acts on major parts of the postural and supporting musculature, because the body must now be actively kept in balance. On account of these constantly required minimal compensating movements and tensings of the musculature of the foot in seeking to maintain a stable standing position, wearing MBT shoes is like permanently performing sensorimotor training and works additional parts of the musculature of the skeleton. In particular, neglected muscles are trained, posture and gait pattern are improved and the body is toned and shaped. Furthermore, wearing MBT shoes can alleviate back, hip, leg or foot ailments and joint, muscle, ligament or tendon injuries to as well as relieve hip and knee joints. The known bottoms of the MBT shoes have a considerable thickness.
Footwear of a similar kind is also known from WO 2006/065047 A1.
Furthermore, WO 99/05928 discloses a shoe which is suitable in particular for skateboarding, the upper of which is joined by means of Strobel seams to a woven or nonwoven insole. The insole, preferably produced from a stable nonwoven, has forefoot slits and star-shaped heel cuts, to improve the bending properties of the insole. In a heel cutout of the midsole, a shock absorbing cassette is arranged.
It is an object of the present invention to provide a walking device of the generic type with a shoe bottom of smaller thickness that still has the known properties of the walking device of the generic type.
This object is achieved by a walking device which has the features of patent claim 1.
According to the invention, the reinforcing element is no longer integrated in the midsole but is produced as a separate component and then fastened to the midsole, for example by adhesive bonding. In the case of the walking device according to invention, the reinforcing element consequently forms an insole.
In the case of the known walking devices of the generic type, the reinforcing element has in the heel region and in the midfoot region a thickness of about 6 mm and the reinforcing element is covered on top and underneath by the material of the midsole. The upper covering of the midsole, on which a thin top sole may optionally be arranged, forms the foot bed. By contrast with this, the walking device according to the invention does not have any covering in the form of material of the midsole above the reinforcing element, and preferably the reinforcing element, on which a thin top sole may optionally be arranged, forms the foot bed. Moreover, the reinforcing element can be made thinner, in particular in certain regions. This has the overall effect of providing a walking device with a shoe bottom of a smaller height.
In a preferred way, the upper of the walking device is fastened to the reinforcing element. This makes it possible to produce the upper together with the reinforcing element as one structural unit, which is then joined to the shoe bottom.
In this joining it is possible just to fasten the reinforcing element directly to the midsole, but it is advantageous for the upper also to be directly fastened to the midsole at the same time.
Particularly simple production of the walking device according to the invention is achieved by the reinforcing element covering the upper surface of the midsole at least almost completely.
By forming at least one reinforcing rib on the reinforcing element, the latter can be formed with very thin walls in the other regions, without losing its intrinsic stability and rigidity as a result.
Further preferred embodiments of the walking device according to the invention are defined in the further dependent patent claims.
The invention is explained in more detail on the basis of an exemplary embodiment that is represented in the purely schematic drawing, in which:
The embodiment of a walking device according to the invention that is represented in the drawing has a shoe bottom 10, represented in
The shoe bottom 10 has a midsole 16, a soft heel part 20, arranged in a recess 18 of the midsole 16, and an outsole 22. The outsole 22 has—in the unloaded state—a form that is continuously rounded convexly in the walking direction L from the rear end 24 of the shoe bottom 10 to the front end 26 of the shoe bottom 10, in the walking direction L. It is kept in this form by the midsole 16 and the soft heel part 20. This form is typical of shoe bottoms 10 of MBT shoes (MBT is a registered trademark of Masai Marketing and Trading AG, Romanshorn) and is also disclosed, for example, in WO 01/15560.
The outsole 22 is preferably produced from an abrasion-resistant rubber-elastic material. Its modulus of elasticity in the region of the heel is, for example, between approximately 3.4 and 4.1 N/mm2, preferably approximately 3.75 N/mm2, and in the region of the ball is, for example, between approximately 3.8 and 4.5 N/mm2, preferably between approximately 4.0 and 4.3 N/mm2; measured with a punch 20 mm in diameter and a loading of 500 N. However, the outsole 22 may also have approximately the same modulus of elasticity over its entire length. Its Shore A hardness is, for example, approximately 50 to 75, preferably approximately 60 to 70.
The convex form of the outsole 22 has in a heel region lying at the rear, seen in the longitudinal direction L of the shoe, a radius of curvature of approximately 160 mm. In a midfoot region 32, adjoining the heel region 30 in the walking direction L, the curvature of the outsole 22 is less and has a radius of curvature of approximately 280 mm. In a ball and toe region 34, arranged at the front, in the walking direction L, and adjoining the midfoot region 32, the radius of curvature up to at least almost the front end 26 of the shoe bottom 10 is somewhat greater than in the midfoot region 32 and is approximately 390 mm. The data specified above and thicknesses specified further below concern a walking device of European size 37. It may change according to the size of the walking device, although the ratio of the stated radii of curvature of about 1:1.75:2.44 is preferably approximately maintained. In a preferred way, the curvature of the outsole has in the heel region a radius of approximately 150 mm to 200 mm, in the midfoot region a radius of approximately 250 mm to 350 mm and in the ball-toe region a radius of approximately 350 mm to 480 mm. The heel region 30, midfoot region 32 and ball and toe region 34 each extend approximately over one third of the length of the shoe bottom 10. The midsole 16 extends uninterruptedly over these regions.
The soft heel part 20 has in elevation, as illustrated in particular by
Furthermore, in a preferred way, as illustrated in particular by
The soft heel part 20 completely fills the recess 18 between the midsole 16 and the outsole 22 and extends from approximately the rear end 24 of the shoe bottom 10, in the walking direction L, over the heel region 30 to approximately the middle of the shoe bottom 10. In its mid-region, the soft heel part 10 has a thickness of approximately 20 mm.
The midsole 16 is formed as a preferably homogeneous body without a reinforcing element 12 and is produced, for example, from a polyurethane elastomer foam or an ethylene vinyl acetate (EVA). Its upper surface 44 has a form similar to a foot bed, but is provided with a depression 46 extending in the walking direction L. This depression 46 has the greatest depth in the midfoot region 32 and extends, with a progressively smaller, diminishing depth, approximately ⅔ into the heel region 30 and extends with a rapidly decreasing depth into the rear end region of the ball and toe region 34.
The smallest thickness of the midsole 16, measured between the soft heel part 20 and the upper surface 44, is very small and is, for example, about 1 mm. The midsole 16 itself is consequently formed very flexibly in its portion 47 lying above the recess 18, with very low intrinsic stability.
With the end of the recess 18 lying at the front in the walking direction L, the midsole 16 forms a tilting edge 48, extending transversely, preferably at least approximately at right angles, to the walking direction L. In this region, the midsole 16 has the greatest thickness of approximately 29 mm and is significantly more rigid there than in the mid-region of the recess 18; in this respect, compare
The midsole 16 is made harder than the soft heel part 20, which is consequently highly deformed during stepping and standing and absorbs and dampens shocks. During rolling, the tilting over the tilting edge 48 that is familiar for walking devices of this type is then obtained. The (Shore A) hardness of the midsole 16 is preferably approximately 38-44, but it may also be made somewhat softer or harder. It preferably has approximately twice the Shore A hardness of the soft heel part 20. The modulus of elasticity of the midsole is, for example, between approximately 0.7 and approximately 1.2 N/mm2, preferably between approximately 0.85 and 1.05 N/mm2, measured with a punch of 20 mm in diameter and a loading of 100 N.
The ratio of the modulus of elasticity of the soft heel part 20 to that of the midsole 16 is 1:1.4 to 1:3, preferably 1:1.75 to 1:2.4. The modulus of elasticity of the midsole 16 is consequently approximately twice that of the soft heel part 20.
For the sake of completeness, it should be mentioned that the midsole 16 has a peripheral, upwardly directed collar 50, which serves for joining to the upper 14.
As illustrated in particular by
The reinforcing element 12 shown in
The modulus of elasticity of the reinforcing element 12 in the forefoot region is, for example, approximately 8.0 to approximately 13.0 and in the heel region is approximately 12 to 13.5 N/mm2, measured with a punch of 20 mm in diameter and a loading of 1000 N. However, the modulus of elasticity may also be at least approximately constant over the entire reinforcing element 12.
The bending moments of the reinforcing element 12 are in the toe region approximately 70 to 80 Nmm, preferably approximately 75 Nmm, in the ball region approximately 150 to 250 Nmm, preferably approximately 200 to 210 Nmm, and in the ankle region (heel region) approximately 4500 to approximately 6000 Nmm or more, preferably approximately 5100 to 5600 Nmm or more.
The reinforcing element 12 may, for example, have a Shore A hardness between 80 and 120, preferably of approximately 90 to 100.
In the ball and toe region 34, in particular approximately in the front half of this region in the walking direction L, the reinforcing element 12 is preferably more flexibly formed. Here it does not have a reinforcing rib 54 and can be formed more flexibly, for example by the use of a softer, more elastic material component. The two-component or multi-component injection-molding process is suitable for producing such a reinforcing element 12. As indicated in
The reinforcing element 12 extends over the entire upper surface 44 of the midsole 16 up to the peripheral collar 50, only a narrow, peripheral gap remaining between said collar 50 and the reinforcing element 12 for the material of the upper 14, compare
In a known manner, the upper 14 is produced and then its border 68—also known as a lasting allowance—is firmly joined to the reinforcing element 12 by adhesive bonding in the border recess 62. Subsequently, the structural unit comprising the upper 14 and the reinforcing element 12 is placed within the collar 50 onto the upper surface 44 of the midsole 16 and adhesively bonded with the latter over its full surface area, including the collar 50.
The reinforcing element 14 preferably forms the foot bed; however, an insert sole, for example an insole, may also be loosely laid or fastened on it. It may, for example, have a flexible foam covering of approximately 5 mm in thickness, the modulus of elasticity of which is, for example, 0.3 to 0.7, preferably approximately 0.4 to approximately 0.6 N/mm2, measured with a pressure punch of 20 mm in diameter and a loading of 100 N. Preferably, the insert sole is shaped in such a way that it is adapted to the form of the foot. The reinforcing element 12 lends the walking device the stability, in particular in the midfoot region 32 and heel region 30, in order for the walking device itself to have the intentionally soft and destabilizing properties as a result of the soft heel part 20.
Walking tests with a walking device according to the invention under with a loading of 70 kg have shown that the shoe bottom 10 deforms in the heel region 30 by 6 to 7 mm and in the ball region scarcely at all. The soft heel region 20 is compressed by this amount and bears this deformation almost in its entirety.
The soft heel part 20 may be made of the same material as the midsole 16 or a material with similar properties, the soft-elastic properties being achievable by hollow spaces, or recesses. The soft heel part 20 is highly deformable under loading caused by standing and walking; shocks are thereby dampened and, both during walking and during standing, the musculature of the skeleton in particular is worked and trained as a result of the instability of the heel region 30.
Instead of a single reinforcing rib 54, the reinforcing element 12 may have a number of reinforcing ribs, which extend at least approximately parallel in the walking direction L; it is also conceivable that a number of crossing ribs are provided.
For the sake of completeness, it should be mentioned that it is conceivable to join the upper 14 only to the reinforcing element 12 and only to fasten the latter directly to the shoe bottom 10.