Patent Publication Number: US-6341432-B1

Title: Shoe

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to a shoe. 
     Shoes consist of a sole and an upper which surrounds the foot resting on the sole. The soles of shoes often have damping means by which the load exerted on the foot or on the entire body of the runner is eased when running. Known damping means for example are air cushions or gel-filled cavities. 
     A sole with a plurality of damping elements is known (EP 0 695 514 A1). This sole has, in the heel area, the metatarsal area, and the ball of the foot, a plurality of holes extending in the transverse direction and intended to serve as damping cushions. These holes are given a variety of shapes and sizes and have a correspondingly hard or soft damping effect. In one embodiment, a recess is made in the sole from the rear end which is open at the sides so that the area of the sole beneath forms a plate that projects freely to the rear. Such a sole has a very soft damping characteristic in the heel area. 
     A sole is also known for an exercise shoe (DE 94 13 496 U1) by which running on the level is made more difficult for training purposes. This sole is cut away in the area associated with the shoe heel so that the wearer of the shoe can run essentially only in the vicinity of the balls of the feet. As a result, an effect like that obtained running uphill on a 15° slope or when climbing stairs is achieved. A shoe of this kind that promotes running on the balls of the feet is unsuited from the health standpoint since, when running on the balls of the feet, the foot or shoe is placed on the ground with the leg extended and the impact load is transferred directly to the knee and hip joints and the spinal column. 
     SUMMARY OF THE INVENTION 
     In view of the above disadvantages and shortcomings of the shoe known from the prior art, the goal of the present invention is to provide a shoe with which the shock loads that occur when running are transmitted only to a very slight degree, if at all, to the knee and hip joints and to the spinal column. 
     This goal is achieved by a shoe having a sole that extends from a rear heel area through a metatarsal area to a front ball or toe area, said sole being made of a sole body and a sole covering located on the underside of the sole body and a recess that extends approximately from the metatarsal area to the heel area and is provided between the sole body and the sole covering; the area of the sole covering associated with the recess forms a pivoting element that is designed to pivot around a pivot axis that is located in the end area of the recess and facing the metatarsal area. 
     The shoe according to the present invention has a sole composed of a sole body and a sole covering, with a recess extending approximately from the metatarsal area to the heel area, said recess being provided between the sole body and the sole covering so that the area of the sole covering associated with the recess, when placed on a support, is pivoted away upward around a pivot axis so that the shoe is placed very softly on the support. 
     When the shoe is placed on the support in the vicinity of the pivot axis, it tilts around the pivot axis with the ball or toe area on the support. As a result, the foot and the lower leg are displaced slightly forward and the knee is automatically bent slightly. A leg bent at the knee accepts the impact load through the bones of the skeleton and the surrounding musculature without the impact load being transmitted to the joints or the spinal column. 
     The shoe according to the present invention therefore produces a rounding effect, in other words a rolling action as it is placed on the support so that the impact load exerted on the sensitive joints or on the spinal column is considerably reduced. 
     In the standing phase, the wearer of the shoe is also placed in a therapeutic posture, in other words a posture with the knees forced to bend at an angle so that the spinal column is also relieved of a load when standing. 
     Hence, the invention is based on the knowledge that in conventional shoes, despite costly and cumbersome damping elements, the impact load is transmitted directly to the joints and the spinal column since, with these shoes, the foot or the shoe can be placed on the support with the leg extended. 
     Preferred embodiments of the present invention are described in the dependent claims. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     In the following, additional designs, features, and advantages of the present invention will be discussed in greater detail with reference to four embodiments that are shown schematically with reference to FIGS. 1 to  6  as examples. 
     FIG. 1 is a side view of a first embodiment of a shoe according to the present invention; 
     FIG. 2 is a side view of the shoe in FIG. 1 while being subjected to a load on the heel area while setting down or rolling away the foot; 
     FIG. 3 is a side view of a second embodiment of a shoe according to the present invention; 
     FIG. 4 is a side view of a third embodiment of a shoe according to the present invention; 
     FIG. 5 is a side view of a fourth embodiment of a shoe according to the present invention; and 
     FIG. 6 is a side view of the shoe in FIG. 5 with the heel area being subjected to a load as the foot is set down or rolled away. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Identical reference numbers in FIGS. 1 to  6  refer to the same or similar parts of the shoe according to the present invention. 
     Shoe  1  according to the present invention has a sole  2  and an upper  3  located thereon, said material surrounding a foot (not shown in FIGS. 1 to  6 ) of a runner. Upper  3  can be closed by shoelaces, hook and loop fasteners, or the like and has an opening  4  through which the foot extends upward in the area of the ankle. 
     Sole  2  extends from a rear heel area  6  through a metatarsal area  7  to a front ball or toe area  8 , with each of these areas  6 ,  7 ,  8  extending over approximately one-third of the length of shoe  1 . 
     Sole  2  is made of a voluminous sole body  10  and a sole covering  11  located at its underside. Sole body  10  consists of a material with good damping properties such as a polyester-urethane (PU) foam for example, and sole covering  11  consists of an abrasion-resistant material that is preferably profiled on its underside, hard rubber for example. 
     The entire sole  2  has a thickness that increases from ball and toe area  8  to heel area  6  so that sole  2  forms a wedge in a side view. The sole top forms an angle α with the underside of the sole and this angle is in the range of approximately 8° to approximately 20°. 
     Between sole body  10  and sole covering  11  is a recess  13  that expands in a wedge shape from metatarsal area  7  to heel area  8 . Sole body  10  forms a stop surface  15  adjacent to recess  13 . 
     Sole covering  11  projects freely rearward adjacent a point  13   a  of recess  13  that points toward ball and toe area  8 , with this area of sole covering  11  projecting freely rearward to form a pivoting element  18  which can be pivoted upward against stop surface  15  of sole body  10  around the pivoting area, adjacent recess point  13   a,  between pivoting element  18  and the rest of sole covering  11 . A pivot axis  20  extends pivotably relative to pivoting element  18  through sole covering  11  in the transverse direction adjacent to recess tip  13   a.    
     A pivot angle β between stop surface  15  and pivoting element  18  is in the range of approximately 10° to approximately 30°, especially in the range from approximately 15° to approximately 20°. The tip  13   a  of recess  13  and hence pivot axis  20  are located in the area between the lengthwise center of shoe  1  and heel area  6  which extends over approximately one-third of the length of shoe  1 . 
     Sole covering  11 , especially in the area of pivot axis  20  and pivoting element  18 , has considerable dimensional stability and/or flexural strength and is fiber-reinforced, so that sole covering  11  has considerable intrinsic stiffness. 
     As shown in FIG. 2, shoe  1 , because of the wedge shape of the entire sole  2 , when placed on a support when running, contacts a support by its sole covering  11  in heel area  6  and thus support  22  by its pivoting element  18 . Pivoting element  18  of sole covering  11  is pressed around pivot axis  20  against stop surface  15 . 
     This pivoting movement of pivoting element  18 , despite the considerable dimensional stability of sole covering  11 , results in a very gentle, yielding placement of shoe  1  on support  22 . The restoring force of sole covering  11  is chosen so that no more than 30% and if possible only 10% of the weight of the runner (65 to 75 kg for example) for which shoe  1  is designed is sufficient to press pivoting element  18  against stop surface  15 . 
     When pivoting element  18  strikes stop surface  15  (see FIG.  2 ), the area of sole  2  or of sole covering  11  that extends from pivot axis  20  to ball or toe area  8  is inclined upward and forward relative to support  22  around pivot angle β. Sole covering  11 , when pivoting element  18  is bent away, has an obtuse angle of nearly 180° in the vicinity of pivot axis  20 . 
     When pivoting element  18  strikes stop surface  15 , the gentle placement process in heel area  6  is terminated and the load exerted on sole  2  by the foot of the runner is distributed approximately uniformly over the entire length of sole  2 . As a result, and because of the momentum of the runner directed in the running direction, shoe  1  tips forward around pivot axis  20  and rests its forward area of sole covering  11  on support  22 . 
     This tilting of shoe  1  causes the foot and lower leg of the runner to be displaced slightly forward in the running direction and the knee is bent slightly between the lower leg and upper leg. The maximum load on the foot or on sole  2  appears only after shoe  1  has tilted or after the runner&#39;s knee has bent so that the recoil produced by the impact on support  22  encounters a leg that is already bent at the knee and which can accept the impact load in a gentle manner with elastic flexibility by means of the knee joint with its skeleton and muscles, 
     Shoe  1  according to the present invention thus causes automatic rolling of the foot when running so that by comparison with conventional shoes, a considerably more protective transmission of the impact load to the body is produced. 
     A second embodiment of the shoe according to the present invention is shown in FIG.  3 . This shoe  1  essentially corresponds to the shoe  1  described above; accordingly, the same or similar components have been given identical reference numbers. 
     Shoe  1  according to FIG. 3, in wedge-shaped recess  13 , has a material element in the form of a material wedge  25  made of an open-pored foam. This material wedge  25  is mounted on stop surface  15  of sole body  10  and on pivoting element  18  by means of a glued connection. 
     Sole covering  11  is divided by a slit  27  in the area of pivot axis  20 . The framework of the invention, of course, includes an embodiment without a slit (see for example the fourth embodiment of the present invention shown in FIGS.  5  and  6 ). 
     Advantageously, sole covering  11  is flexible in the vicinity of pivot axis  20  and formed by a taper since, in this embodiment of shoe  1 , it is advantageous that during the setting down phase of shoe  1  on support  22  in heel area  6 , the restoring force of pivoting element  18  is applied if possible only by material wedge  25  in order to ensure that shoe  1  is set down on support  22  as softly as possible. 
     A reinforcing plate  29  is placed In sole body  10  that extends from the lengthwise center of shoe  1  to rear heel area  6 . The reinforcing plate  29  consists of a metal plate or a fiber-reinforced plastic plate and is located at a distance above a pressure distribution part  16 , with reinforcing plate  29  being adapted to the curvature of pressure distributing part  16 . The reinforcing plate  29  extends in the transverse direction over nearly three-fifths to four-fifths of the width of shoe  1  and during the set-down phase during which pivoting element  18  is pressed against stop surface  1   5 , that sole body  10  cannot be tilted downward by the heel. 
     A third embodiment of the invention is shown in FIG.  4 . This shoe  1  has essentially the same structure as shoe  1  described above; accordingly, the same or similar components have identical reference numerals. 
     The wedge-shaped recess between stop surface  15  and pivoting element  18  is enclosed by an air bellows  31 . Two holes  32  are made in sole body  10 , said holes terminating at one end at stop surface  15  and at the other end externally on sole body  10 . 
     A valve  33  is placed In each of the two holes  32  which limits the escape of air from air bellows  31  to the outside so that when pivoting element  18  is pressed toward stop surface  15  by the limited escape of air during the pivoting movement of pivoting element  18 , a predetermined relatively gentle resistance is offered in opposition. 
     When the pressure by which pivoting element  18  is pressed against stop surface  15  is released, pivoting element  18  again pivots into the initial position which runs as a straight line extension of the rest of sole covering  11 , whereupon valves  33  open and permit a rapid flow of air into air bellows  31 . 
     Pivoting element  18  of sole covering  11  is made in one piece with the rest of sole covering  11  and has a certain degree of dimensional stability or flexural strength so that it automatically pivots back into the initial position following compression of air bellows  31 . 
     The fourth embodiment according to FIG. 5 essentially corresponds to the second embodiment according to FIG. 3, with the only difference being that recess  13  is not wedge-shaped but essentially in the form of a circular section and is filled with a material element  25  made of open-pored plastic. 
     According to a feature essential to the invention, sole  2  is raised laterally or provided with a very thin lateral covering in the form of side walls made of rubber which cover the plastic core externally for protection and can readily be compressed like a bellows. 
     In the present invention, therefore, the action of recess  13  is so designed that when rolling on pivot axis  20 , recess  13  or its filling does not exert an elastically flexible effect through material element  25  but yields with practically zero force up to the stop when sole covering  11  comes to rest against a hard unyielding area of shoe  1 . 
     Shoe  1  according to the four embodiments described above, is characterized by the fact that when running, a rolling of shoe  1  or the foot on the support is automatically produced. This is effected by wedge-shaped recess  13  between sole body  10  and sole covering  11 , since sole covering  11  deflects upward with its pivoting element  18  when subjected to a load in heel area  6  and forms in a gently yielding fashion an obtuse angle at sole  2  whose point is located in the vicinity of pivot axis  20 . 
     Shoe  1  tilts around this obtuse angle in a forward direction so that the knee of the runner is bent and the impact load is received by the runner with a bent knee. The impact load is not transmitted to the sensitive joints and spinal column but is received by the skeleton and the corresponding musculature. 
     The invention is not limited to the above four embodiments described earlier; the individual skilled in the art can readily devise additional modifications of the invention. For example, the scope of the invention also covers an embodiment in which sole body  10  and sole covering  11  are made in one piece and/or of one part.