Abstract:
A footwear sole, more particularly a sports footwear sole, is provided. The extension of the sole can be adjusted in a transverse direction. The sole comprises a deformable portion made of the same material as the rest of the sole and is made with no discontinuity with the rest of the sole. The deformable portion extends in the longitudinal direction of the sole over the whole length of the sole or at least over a substantial portion thereof. Owing to this solution, the sole does not have any discontinuity areas and the non-uniformities in the structural features of the sole, for instance in terms of flexional and torsional rigidity, are remarkably limited.

Description:
BACKGROUND 
       [0001]    The present invention relates to a footwear sole, more particularly to a sports footwear sole. More particularly, the invention relates to a footwear sole the extension of which in the transverse direction can be adjusted. 
         [0002]    It is known that both the comfort and the performance of footwear, for example of sports footwear, are strictly related to the conformity of the footwear to the specific morphology of the particular user. This correlation is especially pronounced in the case in which the footwear comprises a rigid, non-deformable element, as with a sports footwear comprising a substantially soft inner liner and a substantially rigid, non-deformable outer shell. 
         [0003]    Reference can be made, by way of example, to ski boots. In the case of ski boots, not only does the conformity of the footwear to the morphology of the foot of the particular user increases the user&#39;s comfort, but it also improves the maneuverability of the ski, since even minimal movements of the user&#39;s foot are transmitted effectively to the ski boot and from this to the ski. 
         [0004]    In particular, for the same length of the foot—and therefore for the same footwear size—there are users with a particularly large plantar surface, and others with a particularly narrow plantar surface. It is therefore evident that the same footwear may not fit all users with the same footwear size equally well. 
         [0005]    It is also apparent that making custom-made footwear, while allowing efficient customization on one hand, would on the other hand involve high manufacturing costs and, consequently, very high, non-competitive market prices. 
         [0006]    In the past, sports footwear were developed which, starting from a standard, non-customized article, which could therefore be manufactured on a large scale, allowed some degree of customization. In particular, footwear were developed having a transversely adjustable sole, so that the transverse width of the sole could be increased or reduced for adapting it to users having a wider or narrower plantar surface, respectively, than an average one. 
         [0007]    Still referring to the specific example of ski boots, ski boots were developed comprising a substantially soft inner liner and a substantially rigid outer shell, in which the sole of the outer shell is adjustable in a transverse direction in order to adapt the shell—and consequently the ski boot as a whole—to users with a wider or narrower plantar surface than the average one. 
         [0008]    By way of example, the documents CH 486 857 and CH 515 002 both describe a ski boot comprising a sole consisting of two separate side portions connected to each other by means of an elastic joint interposed therebetween and extending in the longitudinal direction; adjusting screws allow to adjust the transverse extension of the elastic joint by virtue of its deformability, so as to vary the width of the sole. Document EP 1 683 434 shows a substantially analogous solution applied to generic sports footwear. 
         [0009]    These solutions, however, while allowing to adjust the transverse dimension of the sole of sports footwear, involve several drawbacks. The main drawbacks of the solutions arise from the fact that a discontinuity is introduced in the footwear sole. Firstly, the discontinuity represented by the elastic joint brings about a very remarkable localized reduction in the flexional and torsional rigidity of the sole. Secondly, the connecting areas between the side sections of the sole and the elastic joint interposed therebetween are subject to wear and consequent detachment. This leads to a malfunctioning in the adjustment of the sole on one hand and to a loss of tightness of the sole with respect to the outer environment on the other hand. In particular, in the case of ski boot, snow and water can penetrate the boot. 
         [0010]    Document EP 2 335 506 describes a sole intended for the shell of ski boot and comprising a slot extending in a substantially longitudinal direction and adjusting elements for controlling deformation of the slot so as to bring closer/spread apart the edges thereof: in this way the overall width of the sole of the ski boot shell can be customized. This solution, too, involves several drawbacks related to the presence of a discontinuity (the slot) in the footwear sole. Firstly, there is inevitably a very remarkable localized reduction in the flexional and torsional rigidity of the sole in the area of the slot. Secondly, the slot constitutes a passage to the outside, which may involve snow and water infiltrations in the boot, unless specific sealing elements are provided, which would in any case involve a more complex and—therefore—more cost-expensive structure. 
         [0011]    The main object of the present invention is therefore to provide a footwear sole that is adjustable in the transverse direction while at the same time being free from the drawbacks described above. 
         [0012]    Another object of the present invention is to provide a footwear sole that is adjustable in the transverse direction while at the same time having a simple and cost-effective structure, with a limited number of components. 
         [0013]    These and other objects are achieved with the footwear sole as claimed in the appended claims. 
       SUMMARY 
       [0014]    Owing to the fact the footwear sole according to invention comprises a deformable portion which is made of the same material as the rest of the sole and is made without discontinuity with the rest of the sole, the non-uniformity in the features of flexional and torsional rigidity are remarkably limited with respect to known solutions. 
         [0015]    In addition, the absence of connecting areas between portions of the sole that are made of different materials eliminates the possibility of detachment and the consequent risks of malfunctioning and infiltration of water and foreign bodies from the outer environment. 
         [0016]    The deformable portion extends in the longitudinal direction of the footwear sole—along the longitudinal axis of the sole or in parallel thereto—at least over a substantial portion of the length of the sole. 
         [0017]    According to a preferred embodiment, the deformable portion is made as a bellows-like portion, the pleats of which can be more or less compressed/stretched so as to vary the extension of the bellows-like portion in the transverse direction and therefore, in the end, of the sole as a whole. 
         [0018]    According to a preferred embodiment, the deformable portion is made as a single piece with the rest of the sole, during a single step of injection molding. 
         [0019]    According to an alternative embodiment of the invention, the deformable portion is made as an element which is double-molded or over-molded with respect to the rest of the sole; such construction allows, for the same material, to obtain, for the deformable portion, a lower rigidity than the rest of the sole. 
         [0020]    In its simplest embodiment, the deformable portion is deformed as a consequence of the insertion of the user&#39;s foot into the footwear. 
         [0021]    However, the footwear sole of the invention preferably comprises an adjusting arrangement for adjusting the deformable portion in order to vary the extension thereof in a transverse direction. 
         [0022]    Advantageously, according to a preferred embodiment of the invention, the adjusting arrangement is configured so as to vary the extension of the deformable of the sole by overcoming its resistance and to adjust the deformation of the deformable portion to a desired value so that the sole maintains unchanged its flexional and torsional rigidity. 
         [0023]    For this purpose, the adjusting arrangement comprises one or more rigid members, to which the deformable portion of the sole is anchored at one or both of its longitudinal ends and which support the adjusting elements of the deformable portion. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0024]    Further features and advantages of the invention will become more apparent from the following detailed description of a preferred embodiment of the invention, given by way of non-limiting example with reference to the annexed drawings, in which: 
           [0025]      FIG. 1  schematically shows the footwear sole according to the invention, viewed from the outside and illustrated in a first configuration; 
           [0026]      FIG. 2  schematically shows the footwear sole according to the invention, viewed from the outside and illustrated in a second configuration; 
           [0027]      FIG. 3  is a section taken along the line of the footwear sole of  FIG. 1 ; and 
           [0028]      FIG. 4  schematically shows a detail of the footwear sole according to the invention relating to the adjusting arrangement for adjusting the deformable portion of the sole, viewed from the inside. 
       
    
    
       [0029]    It is clear that herein the term “inside” means the side of the sole facing the user&#39;s foot and the term “outside” means the side of the sole facing the outer environment. 
       DETAILED DESCRIPTION 
       [0030]    The preferred embodiment of the invention described below in detail refers to the application of the invention to a sole for a ski boot, and more particularly to a sole for the outer shell of a ski boot. This embodiment is in no way to be intended as limiting the scope of the invention and the invention can be applied to the sole of any footwear for which it is deemed necessary or advantageous to customize the width of the sole of the footwear for adapting it to the specific morphology of a particular user. Further non-limiting examples of application of the invention comprise footwear for skates (both roller skates and ice skates), mountaineering and trekking footwear, motorcycle footwear and safety footwear. 
         [0031]    Referring to  FIGS. 1 and 2 , there is schematically illustrated the sole  1  of a substantially rigid outer shell of a ski boot. According to the invention, the sole  1  comprises a deformable portion  3  extending longitudinally along the sole  1  and is arranged between two side portions  5   a,    5   b.    
         [0032]    The deformable portion  3  can extend along the longitudinal axis L of the sole  1  (as in the illustrated example) or in parallel thereto. The deformable portion  3  can extend over the whole length of the sole  1  (as in the illustrated example) or over a portion of the length. 
         [0033]    According to the invention, the deformable portion  3  is made of the same material as the side portions  5   a,    5   b  and is made continuously with the side portions and without discontinuity therewith. In particular, the deformable portion can be made as a single piece with the side portions  5   a,    5   b  or, alternatively, as an element double-molded or over-molded with respect to the side portions, but in any case of the same material as the side portions and without junctions between the different portions. 
         [0034]    The deformable portion  3  is therefore deformable not by virtue of the material of which it is made, but rather because of its geometrical configuration, which allows to vary the extension thereof in the transverse direction, i.e. to vary the distance between the two side portions  5   a,    5   b.    
         [0035]    In particular, in the illustrated embodiment, the deformable portion  3  is made as a bellows comprising a plurality of longitudinally oriented pleats  7 , as better visible in  FIG. 3 :
       by exerting a traction in the transverse direction (arrows F 1 ) onto the pleats  7  it is possible to spread them apart from one another, thus increasing the extension of the deformable portion  3  in the transverse direction and spreading apart the two side portions  5   a,    5   b,  thereby obtaining a configuration suitable for users with a wide plantar surface (configuration shown in  FIG. 1 );   by exerting a compression in the transverse direction (arrows F 2 ) onto the pleats  7  it is possible to bring them closer to one another, thus reducing the extension of the deformable portion  3  in the transverse direction and bringing the two side portions  5   a,    5   b  closer to each other, thereby obtaining a configuration suitable for users with a narrow plantar surface (configuration shown in  FIG. 2 ).       
 
         [0038]    By virtue of the fact that the deformable portion  3  is made of the same material as the side portions  5   a,    5   b  and has no junctions, the sole  1  has no areas of discontinuity, which ensures more robustness and integrity of the sole and more uniform features, especially regarding its flexional and torsional flexibility. 
         [0039]    Still referring to  FIGS. 1 and 2 , although it is possible to imagine that the sole  1  is not provided with any adjusting elements and that the deformation of the portion  3  takes place spontaneously as a consequence of the insertion of the user&#39;s foot into the footwear, it is preferable to provide adjusting elements for adjusting the deformation of the deformable portion. 
         [0040]    In the illustrated embodiment, the deformable portion  3  of the sole  1  is anchored at its opposite longitudinal ends to corresponding rigid members  9 ,  11 . In particular, the rigid members are made as plates  9 ,  11  made of a material having a much higher stiffness than the material of which the sole  1  is made, and arranged at the toe region and at the heel region of the sole  1 , respectively. Fastening elements  13 —for example in the form of screws or the like—are provided for firmly anchoring each of the plates  9 ,  11  to the sole  1 , at the corresponding ends of the deformable portion  3  of the sole. 
         [0041]    The plates  9 ,  11  support the adjusting elements  15  for adjusting the transverse extension of the deformable portion  3 , the adjusting elements  15  being arranged on the plates  9 ,  11  at a distance from the fastening elements  13  enough to allow adjustment of the deformation of the deformable portion  3  in the transverse direction. The adjusting elements can be arranged on one side only or—preferably—on both sides of the deformable portion  3 , so as to be capable of exerting a traction/compression force onto the pleats  7  of the deformable portion  3  on one side only or on both sides, respectively. 
         [0042]    In addition, the adjusting elements can be configured so as to cause a symmetric traction/compression of the deformable portion  3  or so as to selectively cause a traction on either side of the deformable portion  3 , respectively. 
         [0043]    In the shown embodiment, two pair of adjusting elements  15  are provided, namely a first pair on a first plate  9  close to the toe portion of the sole  1  and a second pair on a second plate  11  close to the heel portion of the sole  1 , each pair comprising two elements arranged on opposite sides of the deformable portion  3 . The plate  9  with its corresponding fastening elements  13  and corresponding adjusting elements  15  is also shown in more detail in  FIG. 4 . 
         [0044]    In the illustrated embodiment, the adjusting elements  15  consist of corresponding eccentric elements. Each eccentric element  15  has a cylindrical portion fitted in a corresponding through-hole formed in the rigid plate  9 ,  11 , and an eccentric portion engaged in a corresponding seat in the sole  1 , in the proximity of the deformable portion  3  of the sole. In this way, a rotation of the eccentric element  15  exerts a traction or compression force onto the deformable portion  3  of the sole  1  and a consequent variation of the transverse extension of the deformable portion  3 , whereas the rigid plate  9 ,  11  remains fixed to the sole  1  without deformation or displacement. 
         [0045]    Rotation of the eccentric element  15  can be effected by means of an appropriate tool  100 —for example an Allen wrench or a lever specific for amplifying the torque to be applied—and to this aim each eccentric element  15  has a seat  15   a  in which the tool  100  can engage. 
         [0046]    As anticipated above, the adjustment arrangement of the sole according to the invention comprises at least one adjusting element  15 . 
         [0047]    In the illustrated embodiment, the presence of a pair of eccentric elements  15  on each of the plates advantageously allows separate, independent adjustment of the deformation of the deformable portion  3  on the medial side and on the lateral side of the sole  1 . 
         [0048]    From the above description, it is apparent that the invention allows to achieve the objects set forth above, as it allows to combine the possibility of adjusting the transverse extension of a footwear sole, for adapting it to users with a more or less wide plantar surface, with the need of avoiding any discontinuity and non-uniformity in the structural features of the sole. 
         [0049]    It is further apparent that the above description has been given by way of non-limiting example and that several modifications and variants are within the reach of the person skilled in the art and in any case fall within the scope of the invention as defined in the appended claims. In particular, although the preferred embodiment described above relates to a ski boot, the invention is profitably applicable to a variety of different footwear as well. 
         [0050]    Furthermore, although in the embodiment described above reference is made to a deformable portion made as a bellows, any other geometrical configuration of the deformable portion that allows to vary the extension thereof in the transverse direction can also be used.