The present invention refers to a sole structure for sports footwear, such as ski or snowboard boots, mountaineering boots, in-line roller or ice-skating boots, cycling shoes, motorcycling boots, and any other application in the sports footwear field that requires the use of a sole that is essentially rigid with respect to torsion along the longitudinal axis.
In footwear used in sports activities that require a precise and immediate transmission of the force from the foot to the sports equipment controlled by the user or, inversely, the perception of the sensations coming from the rest point on the ground to the user, a particularly important requirement is the torsional stiffness of the sole along the longitudinal axis to guarantee precision and immediacy of reaction, without delays that could compromise the performance of the athlete or his/her safety. Sports activities in which the requirement of torsional stiffness is particularly important include, by way of example, the following:
One known way of stiffening the sole is the application, inside or outside the sole, of wood inserts, steel plates, carbon-fibre or Kevlar® elements.
Documents
Patent application
A drawback found in the known solutions consists of the fact that the stiffening element is inserted or fastened externally or internally on the sole and accommodated in suitable recesses formed in covering elements forming part of the sole, such as a heel and a toe screwed to the boot as exemplified in Patent application
Another drawback of the known solutions lies in the limited longitudinal extension of the stiffening element, that substantially involves the central part of the sole and extends only minimally in the heel-end and toe-end regions. These regions are particularly critical since, in the case of skiing, snowboarding and skating, they represent the connecting interface to the sports equipment, ski or skate; in the case of motorcycling, they act on the gear shift pedal or on the brake pedal, while in cycling the toe-end supports the coupling interface with the pedal and is therefore the part that imparts power to the thrust on the pedal. It would therefore also be desirable to increase the torsional stiffness of these end regions of the sole, where the main torsional stresses originate. Document
The main objective of the present invention is thus to overcome the drawbacks of the known art mentioned above by devising a sole structure for sports footwear having a higher capacity of resistance to torsional deformations, in particular along the longitudinal axis of the sole.
In the scope of the above objective, a purpose of the present invention is to considerably improve the precision and rapidity of transmission of force between the user's foot and the sports equipment or the ground, eliminating, or considerably reducing, the relative movements between a sole stiffening element and the sole itself.
Another purpose of the present invention is to devise a sole structure for sports footwear in which the increased torsional stiffness substantially involves the whole extension of the sole or a large part of the same.
Another equally important purpose is to achieve a sole structure for sports footwear that attains the above objective and purposes at competitive costs and that can be achieved with the usual known equipments, machinery and tools.
The above objective and purposes, and others that will become more evident in the following description, will be achieved by a sole structure for sports footwear as defined in claim 1.
Further characteristics and advantages of the sole structure for sports footwear according to the present invention will become more evident from the following description of a particular, but not exclusive, embodiment illustrated by way of non-limiting example with reference to the following figures, in which:
With reference to the above-mentioned figures, reference numeral 1 generally indicates a sole structure for a sports footwear; the embodiment illustrated in the enclosed figures refers to a sole of a ski boot, but the following description is also applicable to different sports footwear, according to what is described in the premises, that require a sole structure that is torsionally rigid, unless otherwise specified.
The sole structure 1 includes a midsole 2 provided with at least one centering member 3 defined by a protuberance or a projection, preferably polygonally shaped, extending from the midsole 2 toward the ground; the midsole 2 is provided with a plurality of centering members, collectively indicated with the reference numeral 3, defined by a plurality of protuberances or projections extending from the midsole 2 toward the ground. Such protuberances or projections may be of different shapes, not necessarily polygonal shapes - for example triangular, rhomboidal, trapezoidal, elliptical - depending on their arrangement on the midsole plane 2. The midsole 2 is box-shaped, and thus it is provided with at least one peripheral wall, preferably a front peripheral wall 4 and a rear peripheral wall 5 separated from each other approximately at the region of the arch 6, which extends from the opposite side with respect to an overlying upper or shell, partially shown in the enclosed drawings and indicated with reference numeral 7. A recess 8 is thus defined in the midsole 2 by the peripheral wall or walls 4, 5.
It is herein specified that in footwear provided with a shell of plastic material, such as a ski boot or a skating boot, the midsole 2 is an integral part of the shell, as it is made up of the bottom base of the shell itself, while in footwear provided with a soft upper the midsole 2 is generally a component distinct from the upper, to which it is connected by means, for example, of stitching or glueing.
The sole structure 1 also includes a stiffening element 9 resistant to torsion along the longitudinal axis, for example an element consisting of a plate of metal or carbon fibre material, provided with at least one opening 10 suitable to engage the centering element 3; preferably, the plate is provided with a plurality of openings 10 suitable to engage the corresponding plurality of centering elements 3; the openings 10 are thus formed on the stiffening element 9 according to an arrangement and a form countershaped with respect to the respective centering elements 3 to engage.
Naturally, the stiffening element 9 can be formed in a single piece or by more pieces connected to each other so as to still impart on the footwear the required torsional strength.
The longitudinal extension of the stiffening element 9 substantially corresponds to the longitudinal extension of the midsole 2, or of the recess 8 if the midsole 2 is made in a box-like shape; thus, once it is placed in the midsole 2, or inside the recessed seat defined by the recess 8, the stiffening element 9 extends substantially from the toe-end region to the heel region of the footwear.
Advantageously, the stiffening element 9 has, in the region of the arch 6 if the peripheral walls 4, 5 are separate, one or more side wings 11 to cover and protect the midsole 2 in the area where the front wall 4 and the rear wall 5 are separated from each other.
To complete the sole structure 1, the structure is designed to have a one-piece outsole provided if necessary with a deep-grooved tread for applications, such as mountaineering boots or motorcycling boots, where this characteristic is required, or a number of portions 12, 13, as in the embodiment illustrated in the enclosed drawings, in which the outsole is formed by a front portion 12 covering the toe end and a rear portion 13 covering the heel.
The assembling of the sole structure 1 as described above takes place as follows: the stiffening element 9 is arranged and connected, preferably in a removable manner, on the midsole 2, or within the recess 8 if the midsole 2 has a box-like shape, so that each of the centering elements 3 engages the corresponding opening 10. When the assembling operation is completed, the outsole 12, 13 is overlaid on the stiffening element 9 and fastened, preferably in a removable manner as for example through screws, on the midsole 2. In this manner, the stiffening element 9 is held in position and can be easily replaced in case of breakage or, if the user wishes to vary the degree of torsional and/or flexural stiffness of the sole, with another element of different structural characteristics or made with a different material. An edge trim 14 can advantageously be provided on the peripheral walls 4, 5 of the box-like shaped midsole to facilitate the seating and support of the outsole 12, 13.
Naturally, different methods of assembling the sole structure 1 can be provided for, such as for example glueing the stiffening element 9 or embedding it by overinjection in the midsole 2 or in the recess 8 to achieve a more stable connection, even though it would be permanent and no longer removable, without however departing from the innovative concept of the present invention as defined in claim 1.
With the sole structure thus obtained, it is readily evident how any increase in the weight of the footwear is extremely limited, thanks to the presence of the openings 10, which considerably lighten the stiffening element 9, while however maintaining substantially unchanged its characteristics of torsional strength along the longitudinal axis.
In addition, the engagement and mutual cooperation between the centering elements 3 and the openings 10 prevents, or at any rate considerably reduces, the relative movements between the stiffening element 9 and the midsole 2 along a plane substantially horizontal to the footwear; in such a way, the torsional deformation of the stiffening element 9 is practically prevented, or at least considerably reduced, thus achieving the effect of conferring a greater torsional resistance to the sole structure in general.
Lastly, the sole structure so conceived makes it possible to achieve a greater torsional stiffness substantially along the whole longitudinal extension of the sole, including the toe-end and the heel-end regions. This aspect is particularly important in footwear in which such end regions make up the connecting interface to sports equipment, such as ski boots, snowboarding boots, skating boots or cycling shoes, where torsional deformations originate in one or both of said regions, or in footwear in which these regions are used to operate the controls of a vehicle, such as in motorcycling boots.
From the above description, it is evident how the present invention achieves the objectives and advantages initially foreseen: in effect, a sole structure has been devised for sports footwear capable of considerably and effectively improving the precision and rapidity of transmission of forces from the user's foot to the sports equipment or the ground through an increase in the torsional stiffness of the sole; such increase in torsional strength is achieved thanks to a better and more effective cooperation of the stiffening element 9 with the midsole 2 due to the effect of the engagement between the centering elements 3 and the openings 10 that makes it possible to eliminate, or at any rate considerably reduce, the relative movements and thus also the possibility of torsional deformation, of the stiffening element 9 with respect to the midsole 2.
In addition, as explained above, the increase in torsional stiffness involves substantially the full extension of the sole or a large part of it, thanks to the possibility of seating the stiffening element 9 substantially along the whole extension of the midsole 2, or of the recess 8, and of also achieving in the toe-end and the heel-end regions the engagement between the centering elements 3 and the openings 10. This is particularly appreciated in ski-boots wherein the toe- and heel end regions of the boot engage with the ski binding and the stiffening element 9, affecting the sole structure all along its longitudinal extension including the end portions attached to the front and the rear ski bindings, considerably increases the torsional stiffness of the whole structure.
Naturally, the present invention is susceptible to numerous applications, modifications or variants without departing from the scope of patent protection as defined in claim 1.
In addition, the materials and equipment used to carry out the present invention, as well as the shapes and dimensions of the individual components, can be the most suitable depending on the specific requirements.
This list of references cited by the applicant is for the reader's convenience only. It does not form part of the European patent document. Even though great care has been taken in compiling the references, errors or omissions cannot be excluded and the EPO disclaims all liability in this regard.