EP0110909B1

EP0110909B1 - Heelless outsole for sports shoes

Info

Publication number: EP0110909B1
Application number: EP19830901596
Authority: EP
Inventors: Michael Wolfgang Dipl.-Kfm. Schmohl
Original assignee: Individual
Current assignee: Schmohl Michael Wolfgang Dipl-Kfm
Priority date: 1982-05-28
Filing date: 1983-05-27
Publication date: 1986-12-30
Also published as: DE3368498D1; IT8321183A0; JPS59500947A; DE3220215A1; EP0110909A1; IT1169730B; WO1983004166A1

Abstract

An outsole for a sports shoe, which outsole is preferably of polyurethane or a similar plastics material. The outsole has a shell-shaped inner sole layer (19), which is provided with a profiled bedding and is made from a less dense material, and a flat outer sole layer (18) which is associated substantially only with the bearing surface and is made from material which is denser than the inner layer (19). In the region of the centre of the foot, the outer layer (18) has a trapezoidal recess (20) which is enclosed on all sides by the denser material and through which the less dense material of the inner sole (19) projects to the bearing surface.

Description

Technical field

The invention relates to heelless outsoles for sports shoes comprising an inner sole layer and an outer sole layer forming the tread surface, the inner layer consisting of a lowdensity foamed plastics material and the outer layer is thin in comparison to the average thickness of the inner sole layer and consisting of a plastics material which has a higher density than the inner layer and having an opening which is filled by the less-dense material of the inner layer.

Background art

A heelless outsole of this type is disclosed in the international patent application WO 81/03 112 (PCT/US 81/00590). In this case the outer sole layer is thin in comparison to the average thickness of the inner sole layer and is formed of a relatively dense natural or synthetic ocmposition. It comprises openings in the ball section and/or in the heel section into which the relative lowdensity plastics material composition of the inner layer projects. The inner sole layer also covers the outer sole layer on the inner side thereof with a relatively thin layer, the thickness of which increases from the toes to the heel. The inner surface of the inner sole layer facing the sole of the foot, is formed in a substantial flat manner and comprises recesses which are open at the top.
In DE-U-8126134 a heelless outsole for sports shoes is disclosed which comprises an inner sole layer and an outer sole layer forming the tread surface, the inner layer consisting of a foamed plastics material and the outer material consisting of a wear-resistant material, whereby the inner sole provides a bedding and comprises a raised-up circumferential edge which passes around the heel portion of the foot and resiliently supports the heel while the outer sole is formed of a layer which is relatively thin with respect to the inner sole layer. The inner face of the inner sole layer is practically flat and the thickness of the inner layer remains constant over the length of the sole. In FR-A-1 016468 a heelless outsole for shoes is disclosed which substantially consists of a continuous rubber sole of constant thickness. This rubber sole does not have any openings, neither in the forefoot portion nor in the heel portion nor even in the area of the middle foot. Both, in the forefoot portion and in the heel portion there are provided only flat recesses proceeding from the lower side, in order to insert into the same by vulcanizing conformingly dimensioned patches resistant to wear, for instance made from leather. Practically these patches do not exert any influence on form stability, elasticity or resiliency of the sole as such. With the exception of wear resistance, all the characteristics of the sole are determined by the continuous rubber sole.

Disclosure of the invention

It is the object of the invention to take care of the foot of an athlete to a large extent and to protect it from anatomical overstressing, with the aid of the sports shoe, to reduce the weight of the sole without reducing the resistance to wear of the bearing surface and further and, simultaneously, to ensure that the natural mobility of the foot and the elasticity of the arch of the foot are better than hitherto with sufficient rigidity of the outsole.
This object is achieved in that the inner sole layer provides a bedding with a surface anatomically profiled in longitudinal and lateral directions and comprises a raised-up circumferential edge which continuously passes around the sole of the foot and resiliently supports it on all sides while the opening of the outer sole is confined laterally by narrow edge strips integral with the remaining portions of the outer sole layer and extends over the entire width of the middle portion of the foot between the ball portion and the heel portion and has an approximately trapezoidal outline.
The opening which extends over the entire width of the middle portion of the foot and which is confined laterally by narrow edge strips integral with the remaining portions of the outer sole layer impart altogether a better unrolling capacity and a better twisting possibility about the longitudinal axis of the sole. The outer sole provides a specific framelike bordering for the material of the inner sole which is in this area positively connected with the out sole. Thus, the inner sole material is prevented from being squeezed aside under higher loads which would give the wearer of the shoe a feeling as if the foot were floating on the outer shoe sole. Together with the anatomic adaption of the inner sole to the foot sole there is, thus, ensured a sufficiently close connection between the foot and the outer sole and between the foot and the ground, respectively, imparting to the wearer greater security in executing the movements dictated by the sport.

Disclosure of the invention

As a result of the shell-shaped construction, the profiled bedding for the sole of the foot and the raised up and surrounding edge of the inner sole layer which consists of denser material, a bedding of the foot in the shoe which is effectively reliable and resiliently flexible on all sides, i.e. on the sole of the foot and the adjoining lateral faces of the foot, is ensured. As a result of the profiled bedding for the sole of the foot, considerable proportions of the forces which are effective laterally or longitudinally may be transmitted between the foot and the outsole, so that the edge, which reliably and resiliently supports the foot on all sides, is sufficient to take up reliably the remainder of the forces which are effective laterally or longitudinally.
As a result of the all-round bedding of the sole and the sole edge in the shell-shaped, low-density material of the inner sole layer the athlete's foot is also treated carefully to a large extent and is protected from anatomical overstressing even in the case of great stresses. The high degree of elasticity of the arch of the foot is resiliently supported over the entire width of the central foot area as a result of the material of the inner sole layer projecting into the recessed region of the outer sole layer, the shape of the recess ensuring to a particularly great degree that the natural mobility of the foot and the support of the arch of the foot is ensured in a better manner than hitherto. A further, substantial advantage of the shell-shaped construction of the inner sole layer and the raising up of the inner sole layer to form an edge which passes around the foot and laterally supports it resiliently substantially resides in the fact that this edge, made of material which is less dense, is substantially better able to follow the deformations of the shoe uppers in the regions of high flexibility of the foot, so that these regions of the shoe uppers are subjected to less great stresses by an edge which is too hard, and become fatigued or detached from the edge less rapidly. As a result of this the useful life of the sports shoe is substantially increased.
Since the elasticity of the arch of the foot between the front joint of the foot and the heel joint is not only completely maintained but is also resiliently supported by the resilient deformation of the less-dense material in the central foot region, impacts or the forces occurring during rapid acceleration are absorbed in a substantially improved cushioned manner, to which the large thickness of the less-dense material is a contributing factor. Although the less-dense material in the central foot region extends over the entire width of this region of the foot, the material is also stretched in a frame-like manner at the level of the bearing surface at the sole edges by narrow strips made from the denser material, such that this material cannot move laterally when performing its resilient cushioning function.
The plastics material of the inner and outer sole layers which differ with respect to density may be of differing hardnesses. In a preferred construction the two plastics materials have a degree of hardness which is approximately the same, in spite of the differing densities.
The invention will be explained in greater detail in the following with reference to the accompanying schematic drawings and by means of one embodiment.

Brief description of drawings

Figure 1 shows schematically the lower side or bearing surface of a heelless outsole according to the invention, the usual profiling of the bearing surface not being illustrated;
Figure 2 is a side view of the outsole;
Figure 3 is a section on line III-III in Figure 1; and
Figures 4 and 5 are sections on line IV-IV and V-V in Figure 1, respectively.

Best mode for carrying out the invention

The outsole 1 according to Figures 1 and 2 is intended for a sports shoe and comprises a heelless bearing surface 2 which, at least in the front foot region 3 and the heel area 4, may comprise profiling (not shown) specially adapted to the particular type of sport.
The outsole comprises an outer sole layer 18 which forms the bearing surface and is constructed as a relatively thin layer which is substantially restricted to the bearing surface and the thickness of which does not alter substantially over the extent thereof. This outer sole layer consists of a wear-resistant material which is relatively dense and resistant to abrasion. In particular it consists of compact or only slightly foamed polyurethane. In the toe region the outer sole layer 18 is raised up in the form of a cap to form a shockproof edge 15, as may be seen from Figures 2 and 3.
The outer sole layer 18 comprises a region 20 which is recessed up to narrow edge strips 6, 7 made from the material of the outer sole layer 18, and which, moreover, between the ball section 3 and the heel section 4, extends over approximately the entire width of the central foot region 5. The recessed region 20 comprises an approximately trapezoidal outline with boundary edges 8 to 11 extending in a curved manner. The lateral edges 10 and 11 extend parallel to the edge of the sole, whereas the course of the front and rear boundary edges 8 and 9 is determined to a large extent by the profile pattern associated with the outer sole layer and not illustrated.
The outsole comprises an inner sole layer 19 made from a material which has a lower density with respect to the outer sole layer 18. The inner sole layer 19 may consist of foamed polyurethane.
As may be seen from Figures 3 to 5, the inner sole layer 19 is shell-shaped. For this purpose it comprises an edge 19a to 19c which passes all round the foot, supports it resiliently and laterally, and is raised upwards over the profiled bedding 22, 25, 26 for the sole of the foot. In the front foot region the cap-like edge 15 of the outer sole layer 18 extends over a substantial part of the edge 19a of the shell-shaped inner sole layer 19, which is raised up in this region.
The material of the inner sole layer 19 also fills completely the recessed region 20 of the outer sole layer 18 and comprises a maximum thickness D in cooperation with the profiled bedding in this region. The material-of the inner sole layer-projecting into the recess 20 is designated 21. The material 21 is flush with the bearing surface.
The plastics materials of the two sole layers 18, 19 may have differing degrees of hardness. In the illustrated embodiment the material of the inner sole layer 19 has a Shore A hardness which is up to a third less than the Shore A hardness of the material of the outer sole layer 18. Both sole layers consist of polyurethane.
When polyurethane is used for both sole layers the density of the polyurethane of the outer sole layer 18 is advantageously two to three times higher than the density of the polyurethane of the inner sole layer 19.
It has proved to be particularly advantageous if the plastics material of the two sole layers, with differing densities, have approximately the same degree of hardness. As a result of the differing densities the plastics material of the inner sole layer 19 still obtains an increased cushioning ability.
In an actual case the material of the outer sole layer 18 may consist of a compact to slightly foamed polyurethane with a gross density of approximately 1000 to 1200 kg/m³, whereas a foamed polyurethane which has a substantially lower gross density, namely between approximately 350 and 400 kg/m³, is used as the material for the inner sole layer 19.
If different hardnesses are to be selected for the materials of the two sole layers, the material of the outer sole layer 18 may have a Shore A hardness of 60 to 65°C and the material of the inner sole layer 19 may have a Shore A hardness of 40 to 45°C. In the case of equal hardnesses, the materials of the outer and inner sole layers may be selected in the range from 55 to 65°C (Shore A).
The form of bedding for the sole of the foot is anatomically arranged so that it provides the sole of the foot with a reliable support without restricting the flexibility and the cushioning ability of the foot, it being possible for substantial proportions of the forces occurring to be absorbed and transmitted by this profiled bedding. The thick layer 21 in the region of the recess 20 forms a resilient bridge which has a great cushioning ability and supports the elasticity of the arch of the foot and the mobility of the ankle. A reduced resistance to wear of the sole in the region of the recess 20 does not have a disadvantageous effect since, in the said region, the bearing surface is only subject to slight stresses and wear.
The different materials may also be of different colours. The thick region of low-density material 21 in the central foot region is also particularly well suited to keeping away from the foot foreign bodies which may act on the bearing surface in this region.
The outsole is very lightweight since the greater part consists of a material with a low density. The rigid bordering of the material 21 in the region of the recess 20 prevents any lateral movement of the material when stressed. In this way cushioning occurs exclusively by way of the resilient deformation of this material, this entire material cushioning being distributed over wide regions of the intermediate sole and thus imparting great spring ability to the sports shoe.
The passage in the longitudinal direction of the outsole between the denser material of the outer sole layer 18 and the less dense material in the region of the recess 20 may also be formed gradually. The outsole can be produced according to conventional methods, which need not be described in greater detail.

Claims

1. A heelless outsole for sports shoes comprising an inner sole layer (19) and an outer sole layer (18) forming the tread surface, the inner layer (19) consisting of a lowdensity foamed plastics material and the outer layer (18) is thin in comparison to the average thickness of the inner sole and consisting of a plastics material which has a higher density than the inner layer and having an opening (20) which is filled by the less-dense material of the inner layer, characterized in that the inner sole layer (19) provides a bedding (22, 25, 26) with a surface anatomically profiled in longitudinal and lateral directions and comprises a raised-up circumferential edge (19a to 19d) which continuously passes around the sole of the foot and resiliently supports it on all sides while the opening (20) of the outer sole (18) is confined laterally by narrow edge strips (6, 7) integral with the remaining portions of the outer sole layer (18) and extends over the entire width of the middle portion of the foot between the ball portion (3) and the heel portion (4) and has an approximately trapezoidal outline.

2. An outsole as claimed in claim 1, in which polyurethane is used for both sole layers (18, 19), the density of the polyurethane of the outer sole layer (18) being two to three times greater than the density of the polyurethane of the inner sole layer (19).

3. An outsole as claimed in claim 1, in which the plastics materials of the inner and outer sole layers, with differing densities, have approximately the same degree of hardness.

4. An outsole as claimed in claim 1, in which the plastics materials of the inner sole layer (19) has a Shore A hardness which is up to a third lower than the Shore A hardness of the material of the outer sole layer (18).

5. An outsole as claimed in claim 1, in which the outer sole layer (18) is laterally raised up as an edge only in the region of the toes in order to form a front buffer edge (15) and covers at least partially the raised up edge (19a) of the inner sole layer (19).

6. An outsole as claimed in claim 1, in which the lateral edge (19a-19d) of the inner sole layer (19) is of approximately the same thickness as the outer sole layer (18).