Multilayer sole for sport shoes

Abstract

The sole comprises three layers, including (a) an outer or ground contact sole (7) having flexibility, ground-gripping, and abrasion-resistance properties, (b) an upper or comfort layer (8) positioned directly beneath the foot and having elastic shock-absorption properties, and (c) an intermediate layer or rib (9) positioned directly between the upper portion of the contact layer (7) and the lower portion of the comfort layer (8) and having torsional rigidity properties which provide both for the distribution of shocks sensed by the contact layer (7) and for their diffusion over the comfort layer (8) before they come into contact with the foot (4).

Description

[0001]This application is a continuation of application Ser. No. 07 / 995,083 filed Dec. 22, 1992, now abandoned.OF THE INVENTION[0002]The present invention relates to soles for sport shoes made with a laminated profile comprising multiple layers performing distinct functions, respectively. This sole is mounted on an upper and may or may not incorporate a projecting outer heel-piece in its rear portion.BACKGROUND OF THE INVENTION[0003]In shoes particularly intended for mountain sports, e.g., cross-country skiing, Nordic hiking, and mountain hiking in general, attempts have always been made to produce soles making it possible to obtain, simultaneously, torsional stiffness properties in relation to the longitudinal axis of the sole combined with good flectional properties, in particular in the area of the metatarsals.[0004]This goal is sought most notably in cross-country skiing and Nordic hiking, where the boot cooperates with the ski and must provide optimal guidance of the latter.[00...

AI Technical Summary

Benefits of technology

[0038]an outer, or contact, layer with determinate properties of flexibility, gripping, and abrasion-resistance which allow, simultaneously, good foot extension, good ground traction, and a high level of resistance to wear;

[0042]Moreover, placing the comfort layer directly between the foot and the “rib” layer prevents this rib layer from interfering with comfort, and thus gives optimal comfort.

[0043]Finally, the effectiveness of the outer, or contact, layer is improved because the rib layer comes into contact and cooperates directly with this outer layer, the rib layer thus constituting, for the contact layer, a kind of framework which prevents generalized deformations of the contact layer, in the manner of the radial casing of an automobile tire, and allowing the user of softer, and thus more adherent, rubbers.

Problems solved by technology

In this case, the efficiency of the second, comfort layer is impaired because of the presence of the reinforcement element in its central plane.

Moreover, the presence of a lower portion of the insert positioned between the reinforcement element and the contact sole increases proportionally the height and weight of the assembly.

In these latter cases, the principal disadvantage lies in the fact that the rigid layer is in direct contact with the foot and imparts excessive flectional rigidity to the sole.

This solution has proved to be costly, given the complexity of the mold made for that purpose and of the simultaneous-injection equipment used; furthermore, this solution offers no comfort layer.

This stiffness can not be achieved using soles made only of rubber, since they would have to be too thick and, consequently, too heavy.

Moreover, it is difficult to control with precision the rigidity of a rubber sole, in particular in different directions.

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