Patent Publication Number: US-2016235156-A1

Title: Shoe Sole, Method of Manufacturing Such a Shoe Sole and Shoe Having Such a Sole

Description:
This application claims the priority of German Patent Document No. DE 10 2015 102 157.9, filed Feb. 15, 2015, the disclosure of which is expressly incorporated by reference herein. 
     BACKGROUND AND SUMMARY OF THE INVENTION 
     The invention relates to a shoe sole for an orthopedic shoe that has a heel portion and a forefoot, wherein the heel area has the appearance of a damper and the forefoot area comprises an elastic resilient rotary element having an axis of rotation perpendicular to the shoe sole, wherein the rotary element has a base that connects to the underside of the shoe sole, and wherein the rotary element is so designed that it allows at least a limited external rotation of the shoe sole relative to the base about the rotational axis. 
     Such soles are known, wherein the damping characteristics of the damper performance are less pronounced depending on the use of the shoe. 
     In the field of sports shoes, it is known that the front portion of the shoe sole can be provided with a rotary element, so as to avoid injury. From U.S. 2009/0113761 A1, e.g., a rotary element is known, which is flush with the underside of the hoot sole. The rotary element has a base at the top of which a rotating disk is attached, which lies in a ring with respect to which it can rotate. Above the ring there is a cover plate, wherein between the end plate and the rotary plate a spring element is arranged which allows a symmetrical deflection of the rotating plate over the closure plate. 
     Similar designs are known from GB 2506694 A as well as from U.S. Pat. No. 6,035,559 A. The rotary elements are arranged centrally in the forefoot and allow a symmetrical deflection on both sides. 
     In orthopedics, there is the following problem, however. 
     Performance dampers are used as orthopedic elements to influence the running and walking behavior of individuals with musculoskeletal complaints, in people with hip problems, it has been shown that these measures alone are not sufficient to achieve a fluid gait. 
     When walking, the free leg is moved forward for execution of a step, wherein the pelvis follows this movement by a rotating forward movement around the hip joint of the supporting leg. In people with hip problems this causes pain, so these tense and stiffen the hip of the standing leg, however, this leads to the step being shortened. 
     The above-cited solutions are known from the field of sports, but are not suitable here because especially the symmetrical configuration of the provision is not an exact adaptation to the specific needs of people with hip problems when walking. 
     Another condition for use in orthopedics is that the position of the axis of rotation of the rotary element can be adapted to the walking behavior of the shoe wearer. 
     The invention is thus based on the objective of providing a shoe sole or a shoe that is customized to the gait of a person to allow him or her a fluid gait, even with hip problems. 
     To solve the problem, the invention proposes that the transverse extension of the rotary element is at least 30% smaller than the transverse extension of the shoe sole in the forefoot area, so that the position of the rotary element in the manufacture of the shoe sole between a position at the outer edge of the shoe sole and a position at the inner edge of the shoe sole can be determined, and that the resilience with an elastic return is smaller for an external rotation than that for an inner rotation. 
     By this design of the shoe sole with a rotary element, the rotation of the pelvis from the hip joint of the supporting leg is transferred to the shoe sole. In a case of a step movement of the free leg, the basis of the rotary element in the supporting leg&#39;s shoe remains on the ground, which allows the shoe, due to the rotary element, to rotate outward relative to the base. Thus, the leg rotates as a whole about a vertical axis when the free leg takes a step forward. Thus, the rotation of the pelvis at the hip joint is minimized, if not avoided altogether. Since the rotational load of the hip joint is reduced accordingly, a fluid walking motion is achieved again with a sufficiently large step width. 
     An outward rotation movement of foot means that the forefoot rotates outward in relation to the body of the person. This means for the right foot, that it—viewed from above—rotates clockwise, and for the left foot, that is rotates counterclockwise. The term. “external rotation” is used simply to describe the direction of rotation, but not the position of the rotational axis. An external rotation occurs both when the heel stays in position and the forefoot moves outward, but even if the forefoot remains in position and the heel moves inward. 
     The rotation in the sole of the foot should, if possible, take place in the region of the forefoot, over which the foot rolls. Therefore, the lateral extent of the rotary element is smaller than that of the shoe sole in the forefoot area so that, in producing the movement, it can be placed in a suitable individual position of the forefoot area. 
     Since the resilience against an external rotation is smaller than that for an inner rotation, the external rotation is opposed by little resistance, so that the compensating rotation for relief of the hip is easily accomplished. A non-desired internal rotation is further prevented due to the greater resilience, so that stable guidance is given to the foot. 
     In principle, the rotary motion of the shoe sole of the shoe or of the supporting leg may, during a step, also be achieved by a smooth bottom side of the shoe sole so that it rotates on the base. However, this runs the risk of slippage, so that according to the invention it is further provided that the underside of the base has a coefficient of friction at least as large as the coefficient of friction of the bottom of the shoe sole in the forefoot. This has the consequence that the underside of the base, which merges flush into the underside of the shoe sole, remains in contact with the ground and sticks to the ground because of the pressure exerted by the shoe sole while walking, so that the shoe sole can rotate relative to this base. 
     The base may be an integral part of the lower layer of the shoe sole. 
     Since the invention requires only a limited external rotation of the shoe sole with respect to the base, it may be completely sufficient that the rotary element allows only one external rotation and an automatic return after one outer external rotation. The return occurs once the supporting leg detaches from the ground and becomes the free leg, which executes the next step. 
     The rotary element can be carried out in different ways. One possibility is that the rotary member has a head above the base, wherein there is a substantially horizontally extending sliding zone between the head and the base. Like the base, the head is an integral part of the shoe sole. Here, however, the base and head are separated by the sliding zone, which allows a mutual rotation of the base and head. 
     In order to dampen the rotation, a gel pad can be provided in the sliding zone. 
     Another possibility is that the rotation element has a torsion element above the base and within the shoe sole, the torsional axis of which is substantially perpendicular to the shoe sole. 
     The torsion element preferably has a certain basic torsion, so that a rotational direction upon application of vertical pressure is set parallel to the torsion axis, corresponding to the desired rotation of the respective outer shoe sole. 
     The torsion element also has an internal tension, which causes the above-mentioned return upon release of the pressure. 
     As a precaution, the torsion element consists of a fiber bundle, wherein the fibers are substantially perpendicular to the shoe sole surface, 
     To give the fiber bundle a preferential direction under an axial compressive load, it is provided that the fibers of the fiber bundle are inclined the external rotational direction. When an axial load is exerted on the fiber bundle, it is inclined even more strongly to external rotation, so that the rotation of the foot is supported. 
     The performance damper and the rotary member described above are adapted according to the respective individual behavior of the person. 
     While running, each person sets his or her heel down in a certain part of the heel area, the contact area, and rolls the forefoot over a certain portion of the forefoot, the roll-off area. 
     In order to achieve optimal shock absorption, the contact damper of the heel area is therefore located in the predetermined contact area. Similarly, the rotary element should be located at the place where the greatest pressure is generated when rolling-off in the forefoot area. 
     The invention therefore provides a method for producing a customized shoe sole, by which the contact area in the heel area and in the roll-off area in the forefoot area is determined for a particular person. A contact damper is then placed in the sole area of the shoe sole and a rotary element in the roll-off area of the shoe sole. 
     In addition, the presence of contact pressure and roll-off pressure can be determined. This allows the contact dampers to be adapted to the measured contact pressure, and the rotary element to the measured roll-off pressure. 
     The invention further relates also to a shoe having a shoe sole described above. 
     In the following, the invention is illustrated by means of an embodiment. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a top view of a shoe sole; 
         FIG. 2  shows a perspective cross-sectional view along line A-A of  FIG. 1  of a first embodiment of the invention with a sliding zone in the shoe sole; 
         FIG. 3  shows a perspective cross-sectional view along line A-A of  FIG. 1  of a second embodiment of the invention with a gel cushion in the shoe sole; and 
         FIG. 4  shows a perspective cross-sectional view along line A-A of  FIG. 1  of a third embodiment of the invention, with a torsion element in the shoe sole. 
     
    
    
     DETAILED DESCRIPTION OF THE DRAWINGS 
     Reference is first made to  FIG. 1 . This shows a top view of a shoe sole  1  for a right foot. Such a shoe sole  1  is adapted to the outer contour of a foot. The shoe sole for a left foot (not shown) is inverted as in a mirror image. 
     The shoe sole  1  has a heel area  2  and a forefoot area  3 . While running, the free leg steps on the ground with the heel area  2 . Here, pressure is applied. Then the shoe sole  1  rolls over the midfoot area and forefoot area  3 , wherein the free leg becomes the supporting leg and an especially higher pressure is exerted in the forefoot area  3 . If in the next step the other leg moves forward, the pelvis of the running person rotates the hip joint of the supporting leg. At the same time, the person tries, if he or she is prevented from rotating the hips, to rotate the foot in the forefoot area about a vertical axis. 
     In order to reduce the pressure during placement of the heel area, a contact damper  5  is located in the so-called contact area  4 . This will be explained in more detail here, because a variety of options are known for this, e.g., foam inserts may be provided. These may be an integral part of the shoe sole, or can be applied later on the upper side of the shoe sole, whereby they become part of the shoe sole. 
     The aforementioned rotation in the forefoot takes place in the so-called roll-off area  6 . There is a rotary element  7 , which—as explained in detail further below—supports the rotation of the shoe sole and the shoe. 
     The exact locations of the contact damper  5  and the rotary element  7  are to be customized. For this purpose, the running behavior of a person is measured and thus the locations of the contact area  4  and the roll-off region  6  and the pressures occurring there are determined. Accordingly, the contact damper  5  and the rotary element  7  are placed and designed according to their property, whether a damping or spring property, for individualized production of the shoe sole. 
     The rotary element can be executed in various ways.  FIG. 2  shows a first embodiment within a longitudinal section of the shoe sole  1 , which is designated as A-A in  FIG. 1 . 
     In the simplest form, for configuration of the rotary element  7  within the shoe sole  1 , there is a lens-shaped sliding zone  10 , which consists of a slot  11  between the base  12  and a head  13 . The thin arch above the slot  11  is intended to indicate the depth of the slot  11  transverse to the section line A-A. The head  13  and base  12  are parts of the shoe sole  1 . In order to facilitate the sliding of the facing surfaces of the base  12  and head.  13 , these surfaces can be provided with anti-friction coatings. A coating with Teflon, would also be conceivable. 
     The lower side of the base, i.e., the side facing the ground, has a high coefficient of friction, so that a contact with the underlying ground is ensured. The base  12 , i,e., the area of the shoe sole below the sliding zone, thus remains at the bottom, while the rest of the shoe sole relative to the base  12  rotates with a rotational movement of the foot, wherein the facing surfaces of the head.  13  and base  12  slide on each other. 
     Instead of a pure sliding zone, a gel pad  14  can be provided—as shown in  FIG. 3 . The rotational movement can be controlled by the viscose properties of the gel used. Again, here the thin arch above the gel pad  14  indicates the depth of the gel pad  14  transverse to the section line A-A. 
       FIG. 4  shows a further embodiment of the rotary element  7 . For this purpose, a torsion element  15  is disposed between the base  12  and the head  13  in the form of a fiber bundle, which completely fills the area between the base  12  and the head  13 . The thin arch above the torsion element  15  indicates the depth of the torsion member  15  transversely to the section line A-A. The fiber bundle consists of a plurality of individual fibers which are substantially aligned parallel to each other and slightly inclined perpendicular to the shoe sole surface. The fiber bundle thereby has a slight basic torsion, i.e., the individual fibers are inclined in the direction of rotation. When a pressure exerted on the torsion element  15 , the fibers are tilted so that the torsional angle is increased. This increases the tension in the torsion element  15 , so that a return is accomplished when the pressure is relieved. 
     LIST OF REFERENCE CHARACTERS 
       1  shoe sole 
       2  heel area 
       3  forefoot area 
       4  contact area 
       5  contact dampers 
       6  roll-off area 
       7  rotary element 
       10  sliding zone 
       11  slot 
       12  base 
       13  head 
       14  gel pad 
       15  torsional element 
       16  fiber bundle 
     The foregoing disclosure has been set forth merely to illustrate the invention and is not intended to be limiting. Since modifications of the disclosed embodiments incorporating the spirit and substance of the invention may occur to persons skilled in the art, the invention should be construed to include everything within the scope of the appended claims and equivalents thereof.