Outsole

An outsole (1, 3), in particular, for athletic shoes (2) can be realized with a significant elastic deformability in the tangential direction so as to also achieve a superior shock-absorption when the foot contacts the ground obliquely and with a slight propulsive force. According to the invention, the sole (1) essentially is only rigid to a tangential deformation beyond at least one critical point of deformation in the region that is deformed to this critical point. This results in a correspondingly increased stability for the runner in the respective point of contact or load application. The runner is also able to push off from the point of load application without any loss in distance. A floating effect on the sole is prevented.

TECHNICAL FIELD

The present invention pertains to an outsole, in particular, for athletic shoes which can also be elastically deformed in the tangential direction.

In this context, the term deformation in the tangential direction refers to a deformation in the direction tangential or parallel to the plane of the outsole or its outer surface which, for example, is caused by shearing. Such a deformation differs from a deformation in the direction perpendicular to the plane of the outsole or its outer surface which, for example, is caused by compression. On a horizontal surface, the tangential direction approximately coincides with the horizontal direction, and the perpendicular direction approximately coincides with the vertical direction.

STATE OF THE ART

Outsoles with elastically resilient outsoles are known in numerous variations, wherein different elastic materials of various hardnesses are used. There also exist outsoles with embedded air or gel cushions. These cushions are intended to elastically absorb the shocks that occur while running and to thusly protect, in particular, the joints of the runner while simultaneously providing a comfortable running experience.

Most athletic shoes currently available on the market have spring characteristics that primary provide a spring effect in the vertical direction or in the direction perpendicular to the running surface, namely in the form of a compression of the sole. However, these outsoles are relatively rigid in the horizontal or tangential direction and do not yield sufficiently if the runner's foot contacts the ground obliquely and with a slight propulsive force. This rigidity in the horizontal or tangential direction is required because a more significant deformability of the sole in the horizontal direction would inevitably result in a floating effect. This would negatively influence the stability of the runner. In addition, the runner would lose at least a certain distance with each step because the sole would initially have to slightly deform in the respectively opposite direction when the runner pushes off in the running direction. Naturally, this floating effect can already be observed in known athletic shoes to a certain degree.

EXPLANATION OF THE INVENTION

The present invention is based on the objective of disclosing an outsole with a simple design which makes it possible to eliminate the above-described floating effect and can also be realized sufficiently soft and resilient in the tangential direction.

This objective is attained with an outsole that can also be deformed in the tangential direction and is characterized by the fact that it essentially is only rigid to a tangential deformation beyond at least one critical point of deformation in the region that is deformed to this critical point.

If the at least one critical point of deformation and the load exerted upon the outsole required to reach this critical point of deformation are suitably chosen by adjusting the hardness or resilience of the outsole accordingly, the sole according to the invention can be realized such that it is also soft and resilient tangentially over a broad range of deformation, and that the critical point of deformation is only reached to a locally limited degree while running, namely in the zone of the sole that is subjected to the maximum load, and only around the time at which this maximum load occurs.

This not only results in a sufficient shock absorption if the runner's foot contacts the ground obliquely and/or with a slight propulsive force, but also in a superior stability at the respective point of impact or load application, from which the runner is able to directly push off again without any loss in distance. The previously described floating effect is prevented in this fashion.

It goes without saying that the critical point of deformation, at which the tangential deformability of the sole according to the invention is terminated, depends on the type of deformation. The deformation does not necessarily have to occur exclusively in the tangential direction. A critical deformation can also be reached during a purely perpendicular or vertical deformation.

According to one preferred embodiment of the invention, the critical point of deformation is only reached after a tangential and/or perpendicular deformation path that is greater than 20% of the deformable thickness of the sole, if applicable, even greater than 50% of this thickness. The absolute deformation value may easily reach a few cm.

With respect to constructive considerations and the materials used, the outsole according to the invention may, in principle, be realized in different ways. Various embodiments are described below with reference to the figures. The following description only pertains to those embodiments in which, for example, two layers of the sole are separated, in particular, by an elastically deformable element, and in which the deformable element has a sufficient deformability and makes it possible to achieve a frictional, non-positive and/or positive engagement between the two layers, namely while essentially preventing the two layers from being displaced parallel to one another.

EMBODIMENTS OF THE INVENTION

One embodiment of the invention is initially described below with reference toFIG. 1. Although this embodiment does not necessarily represent the most preferred embodiment of the invention, it suffices for explaining the essential characteristics of the invention.

FIG. 1shows a running shoe2that is equipped with an outsole1according to the invention. The outsole1is formed by a plurality of profile-like hollow elements3that contain tubular parts3.1and are fixed to the underside of an intermediate sole4of the running shoe1with webs3.2that are integrally formed thereon, e.g., by means of bonding. The hollow elements3are, for example, manufactured from a rubber material that is able to at least partially deform in an elastic fashion under the loads that occur while running. The material preferably has a high static friction with respect to other materials, but also with respect to itself. Several hollow elements3are arranged behind one another in the longitudinal direction of the running shoe2, wherein a gap remains in the region between the ball and the heel. The hollow elements3may respectively extend over the entire width of the running shoe2. However, it would also be conceivable to arrange two or more hollow elements3laterally adjacent to one another as shown inFIG. 2.

For example, if the running shoe2is subjected to a transversely forward load when it contacts the ground as illustrated by the arrow P1inFIG. 1b), the tubular parts3.1are, if their dimensions are chosen accordingly, completely compressed after an initial elastic absorption of the load in the form of a vertical and horizontal deformation. This leads to a frictional engagement between their upper shell3.1.1and their lower shell3.1.2(seeFIG. 3). This frictional engagement generates such a high resistance to an additional deformation of the tubular parts3.1that they practically can only be additionally deformed by the remaining elasticity of the material, i.e., to a negligible degree. In this position and in this state of the outsole1, the runner is in contact with the ground5in such a way that a horizontal shift practically can no longer take place. This means that the runner has a superior stability.

In addition, the runner is able to push off from the position shown inFIG. 2for the next step as illustrated inFIG. 1c) without any loss in distance, namely because the previously described frictional engagement between the tubular parts3.1practically makes it impossible for these parts to horizontally deform to a noteworthy degree in the direction of the load that occurs while pushing off and is indicated by the arrow P2. Naturally, one prerequisite for this is that the load exerted upon the deformed region of the sole is maintained between the time at which the foot contacts the ground and the time at which the runner pushes off again. However, this is usually the case when running normally.

FIG. 2shows the running shoe2according toFIG. 1in the form of a rear view, namely while a) not being subjected to a load and b) while being subjected to a laterally oblique load. In this case, a compression of the tubular parts3.1of the hollow elements3can also take place such that a frictional engagement between their upper shells3.1.1and their lower shells3.1.2is produced. This means that the runner wearing the running shoe2is in contact with the ground5in such a way that a practically unyielding lateral stability is achieved.

The previously described embodiment is characterized by extremely long deformation paths. Between the state shown inFIG. 1a) in which no load is exerted upon the outsole and the state shown inFIG. 1b) in which the frictional engagement occurs, these deformation paths may easily amount to more than 20%, if applicable, even more than 50%. The shoe shown inFIGS. 1 and 2causes the runner to “float on clouds,” but the runner never has an unstable sensation and is always directly and solidly in contact with the ground.

FIG. 3shows a detailed representation of the hollow elements3according toFIG. 1, namely while a) not being subjected to a load and b) while being subjected to a tangential load. A deformation under a vertically downward acting load is shown in part c) of this figure. This part elucidates how the previously described advantages with respect to the stability of the runner and the ability of the runner to push off without any loss in distance are also achieved under a purely vertical load.

The outsole6shown inFIG. 4also comprises tubular hollow elements6.1that, for example, consist of a rubber material. However, the hollow elements are arranged between an upper layer6.2and a lower layer6.3in this case and rigidly connected to the respective layers. The two layers6.2and6.3extend over the entire surface of the outsole. The upper layer6.2may, in principle, be formed by a layer that is provided anyhow or by an intermediate layer of the shoe. The lower layer6.3could also be provided with a profile. The function of the outsole6that is shown inFIG. 4while a) not being subjected to a load basically is identical to that of the outsole1described above with reference toFIG. 2. When the tubular hollow elements6.1are compressed, a frictional engagement between their upper shell and their lower shell is, in particular, also produced in this case as shown in part b) ofFIG. 4. The deformation of the hollow elements6.1under a load is, however, distributed over a larger area due to the thrust effect exerted by the lower layer6.3.

In the embodiment shown inFIG. 5, two separate parts7.1and7.2are respectively provided for the ball region and the heel region of the outsole7. It would, in principle, also be conceivable to realize such a separate design in the other discussed embodiments. In addition, simple webs7.1.3and7.2.3that can be elastically deformed are arranged between the respective upper layers7.1.2and7.2.1and the respective lower layers7.2.1and7.2.2. Under a load, these webs lie flatly between the two outer layers as, for example, illustrated in part b) ofFIG. 5. If a material with a high coefficient of friction is used for the outer layers and the webs, a frictional engagement similar to that described above is produced in the situation shown inFIG. 5b). This means that the upper and the lower layers take over part of the function of the above-described upper and lower shells of the tubular parts shown inFIG. 1. The function of the webs, in contrast, is approximately identical to that of the flanks of the tubular parts. Two such flanks that are arranged opposite of one another are identified by the reference symbols3.1.3and3.1.4inFIG. 3.

In the outsole8shown inFIG. 6, no elastic elements are provided between an upper layer8.1and a lower layer8.2. The upper and the lower layer are connected by peripheral side elements8.3such that a closed volume8.4is formed. This closed volume is filled with a fluid, in particular, a gas such as air or, for example, a gel. In this case, it is important that the outsole can be deformed under the loads that occur while running to such a degree that, as shown in part b), the upper layer8.1and the lower layer8.2can contact one another in the region subjected to the load. A frictional engagement with the above-described properties is also produced in this case if a material with a high coefficient of friction is chosen for both layers.

If an incompressible gel is used as the medium for filling the volume8.4, the entire volume or parts thereof need to be elastically expandable in order to achieve the desired effect. If the volume8.4is filled with a gas, it would be possible to provide an additional valve8.5, e.g., in the heel region. The elastic properties and the resilience of the outsole could then be changed by varying the gas pressure in order to adapt the outsole to, for example, the weight or the running characteristics of a specific runner.

Instead of producing a frictional engagement as in the previously described embodiments, it would be possible to alternatively or additionally produce a positive engagement as shown in the partially illustrated outsole9according toFIG. 7. In this case, a toothing is, for example, arranged between an upper layer9.1and a lower layer9.2.

With respect to the previously described embodiments, it should be noted that individual elements or characteristics thereof may, if applicable, also be utilized in combination with other embodiments. This applies, for example, to the division of the outsole into a ball section and a heel section, as well as to the arrangement of a profile. Frictional engagement means and positive engagement means may be utilized individually or in combination. The embodiments shown inFIGS. 4or5could be combined with the embodiment shown inFIG. 6, wherein an elastic and/or shock-absorbing medium or fluid would be introduced into corresponding hollow spaces in the embodiments according toFIGS. 4or5. Vice versa, mechanical spring elements or shock-absorption elements could be additionally provided inFIG. 6.

LIST OF REFERENCE SYMBOLS

1Outsole2Running shoe3Hollow elements3.1Tubular parts of the hollow elements33.2Webs of the hollow elements33.1.1Upper shell of the tubular parts3.13.1.2Lower shell of the tubular parts3.13.1.3,4.1.4Flanks of the tubular parts3.14Intermediate sole5Ground6Outsole6.1Tubular hollow elements of the outsole66.2Upper layer of the outsole66.3Lower layer of the outsole67Outsole7.1Ball section of the outsole77.2Heel section of the outsole77.1.1,7.2.1Upper layer of the outsole sections7.1and7.27.2.1,7.2.2Lower layer of the outsole sections7.1and7.27.1.3,7.2.3Deformable webs8Outsole8.1Upper layer of the outsole88.2Lower layer of the outsole88.3Peripheral side parts of the outsole88.4Volume of the outsole88.5Valve on the outsole89Outsole9.1Upper layer of the outsole99.2Lower layer of the outsole9P1Arrow indicating the load when contacting the groundP2Arrow indicating the load when pushing off