Abstract:
Outer sole of a climbing shoe made of a flexible natural or synthetic rubber material having the general appearance of a smooth surface, the outer sole including at least in the zone located in its front portion, grooves produced by etching.

Description:
TECHNICAL FIELD 
       [0001]    The invention concerns an outer sole of a climbing shoe. 
       BRIEF DISCUSSION OF RELATED ART 
       [0002]    Climbing is practiced either on natural rock formations such as cliffs or on man-made sites with artificial holds, such as gyms equipped with climbing walls. 
         [0003]    When practicing the sport of climbing, climbers use climbing shoes. 
         [0004]    A climbing shoe must have dimensions that are perfectly adapted to the wearer&#39;s foot. A climbing shoe comprises a sole made of a material consisting of natural or synthetic rubber possessing high flexibility, good deformation properties, and high gripping performance on all kinds of surfaces and particularly on rough surfaces, which are characteristic of rock formations. To this sole is attached an upper, which is generally made of a highly flexible fabric material and strengthened locally by straps on the toe kick and on the back of the heel. 
         [0005]    Due to the fact that a climbing shoe fits the foot of a climber perfectly, and also due to the good capacities of deformation of the shoe and the gripping properties of the sole, a climber is able to move about on a rock formation with very small elevations known as holds. 
         [0006]    The purchase and precision of the climbing shoe result from the following key factors: 
         [0007]    good adaptation of the size and shape of the shoe to the climber&#39;s foot, 
         [0008]    precise and effective placement of the foot on the zone defined as a hold, 
         [0009]    muscle thrust exerted on the hold by the climber, 
         [0010]    purchase of the shoe while thrust is exerted on the zone defined as a hold. 
         [0011]    This purchase results from the gripping properties of the rubber, which is also linked to the muscle pressure exerted by the climber, and from the traction properties of the rubber composing the sole. 
       BRIEF SUMMARY 
       [0012]    The aim of the invention is to improve the gripping and traction properties of the sole on holds. 
         [0013]    To this end, the outer sole of the climbing shoe in question, made of a flexible natural or synthetic rubber material and having the general appearance of a smooth surface is characterized in that it includes, at least in the zone located in its front portion, grooves produced by etching. 
         [0014]    According to a feature of the invention, the depth and the width of the grooves are between 1 and 2 mm and preferably around 1.5 mm. 
         [0015]    The grooves are advantageously etched by laser. 
         [0016]    The micro-grooves formed in the sole enhance the mechanical deformation of the rubber plate by making it more flexible. The surface of the sole in contact with the holds on the rock or with the artificial holds is thus increased, thereby strengthening the grip. 
         [0017]    The grooves improve traction on the holds because the micro-structures of the rock or holds engage with the micro-grooves formed on the surface of the rubber. Lastly, these micro-grooves enhance the deformation of the sole, thus enhancing the adaptation of the shoe and particularly of the sole to different foot shapes. 
         [0018]    According to a feature of the invention, this sole includes a first series of grooves essentially parallel to the inner edge of the sole and essentially extending from the metatarsal support zone located at the base of the big toe to the base of the instep. 
         [0019]    This first series of grooves improves the mechanical deformation of the sole, thus making it flexible, which in turn increases the contact surface between the sole and a hold, strengthening the grip of said sole on said hold. 
         [0020]    Advantageously, most of the grooves of the first series are continuous. 
         [0021]    According to another feature of the invention, this sole includes at least two second series of grooves and preferably three series of grooves, each extending from the first series of grooves and having a generally transverse orientation to the outer edge of the sole, i.e., essentially perpendicular to the tangent to the outer edge of the sole at the theoretical point of intersection between the series of grooves in question and the outer edge of the sole. 
         [0022]    The grooves of the second series of grooves enhance the deformation of the surface of the sole in the center zone thereof, which is essential for improving progression on flat surfaces and rounded holds. 
         [0023]    Advantageously, the grooves of the second series are continuous. 
         [0024]    According to another feature of the invention, the grooves of the first and second series of grooves are distanced from the peripheral edge of the sole, delimiting a non-grooved zone with this edge. 
         [0025]    This smooth zone located between the peripheral edge of the sole and the grooved zones, with a width of around 10 to 15 mm, ensures precision of support and good gripping performance of the load-bearing structure. 
         [0026]    Lastly, and for further improvement of the gripping performance and deformability of the sole, the latter comprises short grooves between 3 to 10 mm in length disposed between the grooves of the second series and extending into the instep zone. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0027]    The invention will be understood more clearly with the help of the following description, which refers to the appended schematic drawing illustrating, by way of a non-limiting example, an embodiment of a climbing shoe equipped with a sole of the invention. 
           [0028]      FIG. 1  is a side view of the inner surface of this shoe. 
           [0029]      FIG. 2  is a view of the outer surface of the sole. 
       
    
    
     DETAILED DESCRIPTION 
       [0030]    A climbing shoe is illustrated in  FIG. 1 . This climbing shoe has an outer sole  2  made of natural or synthetic rubber extending to the heel. To this sole  2  is attached an upper  3  made of a light fabric material strengthened by straps  4 ,  5  passing, respectively, behind the heel and over the top of the foot. The shoe is fastened with self-fastening straps  6 . 
         [0031]    The sole  2  is shown in greater detail in  FIG. 2 . 
         [0032]    This sole includes three main portions, specifically: a front portion A, a center portion B corresponding to the instep, and a back portion C corresponding to the heel. 
         [0033]    The sole includes a first series of grooves  7  essentially parallel to the inner edge of the sole essentially extending from the metatarsal support zone  8  located at the base of the big toe to the base  9  of the instep. The depth and the width of the grooves  7  are between 1 and 2 mm and preferably around 1.5 mm. 
         [0034]    These grooves  7  are continuous and connected to one another at their ends by transverse grooves. 
         [0035]    The sole  2  includes three second series of grooves  10  extending from the first series of grooves  7 , the grooves being in a generally transverse orientation to the outer edge of the sole. These grooves are continuous. 
         [0036]    The grooves of the first series  7  and the grooves of the second series  10  are set back from the peripheral edge of the sole, delimiting a smooth zone  12  with this edge. Between the grooved zones  7  and  10  are formed short grooves  13  between 3 to 10 mm in length. Between the series of grooves  10 , these short grooves  13  are essentially parallel to the long grooves of the series of grooves  10 , whereas in the center portion B of the sole, these grooves increasingly assume a longitudinal orientation. 
         [0037]    As indicated above, these micro-grooves enhance the mechanical deformation of the sole, improve its capacity to adapt to the holds of the terrain, and also enhance its capacity to adapt to the shape of the wearer&#39;s foot. 
         [0038]    Obviously the invention is not limited to the single illustrative embodiment of this sole described above, but encompasses all variants. Hence grooves [could] also be formed in the zone of the heel C, or grooves could be formed in the lateral edge of the sole, or in a zone made of rubber covering the zone of the wearer&#39;s toes. Furthermore, the term “climbing shoe” is to be understood in a broad sense, as this sole could also equip other types of footwear designed for climbing, such as slippers.