Abstract:
A ski includes an elongated body having a bottom surface and a surface modifier having a first surface with a smooth texture and a second surface opposite to the first surface with a rough texture. The surface modifier is reversibly attached to the bottom surface of the elongated body thus providing the bottom surface with a smooth texture suitable for downhill skiing when the second rough textured surface is attached to the bottom surface and with a rough texture suitable for uphill and cross country skiing when the first smooth textured surface is attached to the bottom surface.

Description:
FIELD OF THE INVENTION  
         [0001]    The present invention relates to a ski, and more particularly to a ski that can be used for both uphill and downhill skiing.  
         BACKGROUND OF THE INVENTION  
         [0002]    Skiing is a favorite winter sport and one of the oldest forms of transportation on snow covered grounds. Snow skis are attached to a skier&#39;s boots and are used either for skiing downhill or for cross-country and uphill skiing. Cross-country and uphill skis are relatively long, slender, have a uniform width, a light weight and are thicker in the middle compared to the front and back ends. Downhill skis are shorter, wider, have an hour-glass shape, uniform thickness and a heavier weight. For downhill skiing the bottom surface of the ski that comes in contact with the snow covered ground needs to be smooth, whereas for cross-country and uphill skiing the bottom surface is rough or has ridges in order to provide traction. In some cases a special type of wax is applied to the bottom surface of a cross-country and uphill ski in order to make it stick to the snow covered grounds.  
           [0003]    A special type of skiing is called “Telemark skiing”, named after a region in Norway. Telemark skiing was developed by Sondre Norheim and it involves uphill walking and downhill skiing. Telemark skiing may also include telemark turns (where the outside ski is advanced considerably ahead of the other ski and then turned inward at a steadily widening angle until the turn is completed), skating sections and jumps. In order to accommodate both the uphill walking and the downhill skiing the texture of the bottom surface the ski needs to be adapted.  
           [0004]    One way of changing the texture of the bottom ski surface from smooth to rough is to attach climbing skins. There are two types of climbing skins, woven fabrics and plastic skins. Woven fabrics are usually attached to the bottom surface of a ski via an epoxy. In some cases, woven fabrics may have one self-sticking surface covered with wax paper. The wax paper is removed and the self-sticking surface of the woven fabric is attached to the bottom surface of the ski. The wax paper needs to be reapplied on the self-sticking surface of the woven fabric after the woven fabric is removed from the bottom surface of the ski. This process of removing and reattaching the wax paper on the self-sticking surface of the woven fabric is very cumbersome and especially difficult under harsh weather condition such as wind, snow or rain. Plastic skins are usually attached to the bottom surface of a ski via mechanical means. However, keeping the climbing skins attached to the bottom surface of a ski poses a significant challenge. The epoxy needs to be reapplied several times on the woven fabrics and the mechanical attachment of the plastic skins may break or needs to be reattached. Furthermore, the skier needs to carry with him the climbing skins during the downhill skiing and accessories for applying and carrying the climbing skins during both the uphill and the downhill skiing, which adds weight to the skier. Some systems are bulky to transport, do not function properly when they get wet and need to be frequently dried. It usually takes a long time to mount and dismount both types of the climbing skins on the skis and especially difficult under harsh weather condition such as wind, snow or rain.  
           [0005]    Another method of providing traction during uphill and cross-country skiing is to use waxes. The wax melts and makes the bottom ski surface stick to the snow covered ground. However, waxes usually have a limited operational temperature range and do not provide sufficient traction.  
           [0006]    There is a need for a ski that can accommodate both uphill and downhill skiing without the disadvantages of the existing systems.  
         SUMMARY OF THE INVENTION  
         [0007]    In general, in one aspect, the invention features a ski including an elongated body having a bottom surface and a surface modifier. The surface modifier has a first surface with a smooth texture and a second surface opposite to the first surface with a rough texture. The surface modifier is reversibly attached to the bottom surface of the elongated body thus providing the bottom surface with a smooth texture suitable for downhill skiing when the second surface is attached to the bottom surface and with a rough texture suitable for uphill and cross country skiing when the first surface is attached to the bottom surface.  
           [0008]    Implementations of this aspect of the invention may include one or more of the following features. The surface modifier may cover either the entire bottom surface of the elongated body or part of the bottom surface of the elongated body. In particular, the surface modifier may cover a centrally arranged and axially extending portion of the bottom surface of the elongated body. The elongated body further includes a front portion, a middle portion and a back portion and the surface modifier may have a first segment attached to the bottom surface of the front portion and a second segment attached to the bottom surface of the back portion. The surface modifier may be attached to the bottom surface via a tongue and groove type of attachment. In order to accomplish this type of attachment, the surface modifier may include at least one edge forming the male member of the tongue and groove attachment and the bottom surface of the elongated body may include at least one groove forming the female member of the tongue and groove attachment. Alternatively, the surface modifier may include at least one groove forming the female member of the tongue and groove attachment and the bottom surface of the elongated body includes at least one edge forming the male member of the tongue and groove attachment. The surface modifier may also be attached to the bottom surface via a dove tail type of attachment. The surface modifier may also be attached to the bottom surface by at least one screw and/or at least one bracket. The elongated body and the surface modifier may be made of a material such as wood, metal, plastic, foam, composites, laminates, and combinations thereof. The rough textured surface of the surface modifier may include at least one downward extending protrusion or at least one groove having a height in the range of 3 millimeters to 0.1 millimeters. The ski may further include a binding arranged on the top surface of the middle portion of the elongated body for attaching a skier&#39;s boot.  
           [0009]    In general, in another aspect, the invention features a ski system including a set of two skis each ski having an elongated body having a bottom surface and a surface modifier. The surface modifier has a first surface with a smooth texture and a second surface opposite to said first surface with a rough texture. The surface modifier is reversibly attached to the bottom surface of the elongated body thus providing the bottom surface with a smooth texture suitable for downhill skiing when the second surface is attached to the bottom surface and with a rough texture suitable for uphill and cross country skiing when the first surface is attached to the bottom surface.  
           [0010]    In general, in another aspect, the invention features a method of skiing using a ski system including a set of two skis each ski having an elongated body having a bottom surface and a surface modifier. The surface modifier has a first surface with a smooth texture and a second surface opposite to said first surface with a rough texture, a method of skiing. The method of skiing includes the steps of attaching the first smooth textured surface of the surface modifier to the bottom surface of each ski thus providing the bottom surface with a rough texture and then skiing uphill. Next, reversing the surface modifier and attaching the second rough textured surface of the surface modifier to the bottom surface of each ski thus providing the bottom surface with a smooth texture and then skiing downhill.  
           [0011]    Among the advantages of this invention may be one or more of the following. The invention allows a skier to ski uphill and downhill without having to carry climbing skins or any other additional equipment for converting the uphill skis into downhill skis. The invention provides a ski that is easy to use. Since it does not use climbing skins it does not require the maintenance that is associated with them, such as needing to be dried, epoxied to the bottom of a ski or attaching wax paper to its self-sticking surface for storage. The ski according to this invention has a performance during down hill skiing comparable to a good Telemark ski. The performance of this ski during uphill skiing is at least as good or even better than a good wax-less cross-country ski. The time that it takes to convert the ski from the uphill to the downhill configuration is of the order of seconds. This ski can be used under any kind of weather conditions such as wind, snow or rain and with both hard-packed and light-packed type of snow. This ski may be used for uphill, downhill, cross-country, Telemark and Randonnee type of skiing, among others.  
           [0012]    The details of one or more embodiments of the invention are set forth in the accompanying drawings and description below. Other features, objects and advantages of the invention will be apparent from the following description of the preferred embodiments, the drawings and from the claims. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0013]    Referring to the figures, wherein like numerals represent like parts throughout the several views:  
         [0014]    [0014]FIG. 1 is a side view of a prior art downhill ski;  
         [0015]    [0015]FIG. 1A is a cross-sectional side view of the ski of FIG. 1 along CC′;  
         [0016]    [0016]FIG. 2 is a bottom view of a ski according to this invention;  
         [0017]    [0017]FIG. 3 is a cross-sectional side view of the ski of FIG. 2 along AA′;  
         [0018]    [0018]FIG. 4 is an alternative partial cross-sectional side view of the ski of FIG. 2 along AA′;  
         [0019]    [0019]FIG. 5A is a detailed view of area A of FIG. 4;  
         [0020]    [0020]FIG. 5B is a detailed view of area B of FIG. 4;  
         [0021]    [0021]FIG. 6A is a cross-sectional side view of the ski of FIG. 2 in the uphill configuration;  
         [0022]    [0022]FIG. 6B is a cross-sectional side view of the ski of FIG. 2 in the downhill configuration;  
         [0023]    [0023]FIG. 7 is a bottom view of an alternative embodiment of a ski according to this invention;  
         [0024]    [0024]FIG. 8 is a partial cross-sectional side view of the ski of FIG. 7 along DD′;  
         [0025]    [0025]FIG. 9 is a bottom view of yet another alternative embodiment of a ski according to this invention;  
         [0026]    [0026]FIG. 10 is a partial cross-sectional side view of the ski of FIG. 9 along BB′;  
         [0027]    [0027]FIG. 11 is a bottom view of yet another alternative embodiment of a ski according to this invention;  
         [0028]    [0028]FIG. 12A is a cross-sectional side view of the ski of FIG. 11 along EE′;  
         [0029]    [0029]FIG. 12B is an alternative cross-sectional side view of the ski of FIG. 11 along EE′; and  
         [0030]    [0030]FIG. 13 is a flow diagram depicting the method of using the ski according to this invention for uphill and downhill skiing. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0031]    Referring to FIG. 1, a typical prior art downhill snow ski  100  includes an elongated main body  101  having a top surface  102 , a bottom surface  104 , a front end  101   a , a rear end  101   b , and a middle portion  101   c . Bottom surface  104  comes in contact with the snow during downhill skiing and needs to be smooth in order to be able to glide over the snow. The front end  101   a  of the ski body  101  is usually curved upwards and the middle portion  101   c  forms an arc with the concave portion facing the ground. The top surface  102  includes a binding  138  for attaching the ski to the boots of the skier (not shown).  
         [0032]    Referring to FIG. 1A, in one example, the ski  100  has a honeycomb core  90  surrounded by the main body  101 . The top and bottom surfaces  102  and  104 , respectively, of the main body  101  have a laminated finish  92  and the edges of the ski  118   a  and  118   b  are metallic brackets. Snow skis may be manufactured from a variety of materials including among others wood, metal, plastic, composite material, foam, or a combination thereof. In one example, the snow ski  100  has a length  11  of 190 cm, a width w 1  that varies from 6.5 cm at the front  101   a  and rear  101   b  ends to 5.5 cm at the midpoint  10   c , and a thickness t 1  that varies from 0.95 cm at the front  101   a  and rear  101   b  ends to 1.3 cm at the midpoint  10   c.    
         [0033]    Referring to FIG. 2, a snow ski  100  according to this invention includes an elongated main body  101  having a top surface  102 , shown in FIG. 3, a bottom surface  104 , and a surface modifier  110  attached to the bottom surface  104 . The surface modifier  110  extends the entire length of the ski and covers the central portion of the bottom surface  104 .  
         [0034]    Referring to FIG. 3, the surface modifier  110  has a first surface  112  that has a rough texture and a second surface  113  that has a smooth texture. In one example, surface modifier  110  has a width w 2  of 2 cm and a thickness t 2  of 0.4 cm. First surface  112  includes downward extending protrusions  145  or ridges. The protrusions or ridges have a height of the order of 1 to 2 mm. Surface modifier  110  also has two side extensions  114   a ,  114   b  that extend the entire length of the surface modifier  110  along its sides  140   a  and  140   b , respectively, shown in FIG. 2. Extensions  114   a ,  114   b  have a thickness t 3  of 0.2 cm, which is smaller than the thickness t 2 . In the embodiment of FIG. 3, the main body  101  of the ski  100  has a slot  105  formed near its bottom surface  104 . Slot  105  has two side slots  106   a ,  106   b  formed on the side surfaces of the slot  105  that extend the entire length of slot  105 . Slot  105  has a depth d 1  of 0.5 cm and side slots  106   a ,  106   b  have a depth of 0.25 cm. Surface modifier  110  is inserted into the slot  105  from either the rear end  101   b  or the front end  101   a  and is held in place by a tongue and groove type of attachment. Extensions  114   a ,  114   b  of the surface modifier  110  form the male surfaces and side slots  106   a ,  106   b  of the slot  105  form the female surfaces for mating the sides of the surface modifier  110  and slot  105  in a tongue and groove fashion. This tongue and groove type of attachment holds the surface modifier  110  in place and prevents it from moving sidewise. Longitudinal motion of the surface modifier  110  is prevented by two screws  128   a ,  128   b , and front and back brackets  60   a ,  60   b , respectively, shown in FIG. 2.  
         [0035]    In an alternative embodiment, shown in FIG. 4, the tongue and groove attachment configuration is reversed. In this embodiment the slot  105  has side extensions  108   a ,  108   b  that form the male surfaces and surface modifier  110  has side slots  116   a ,  116   b  that form the female surfaces for mating the sides of the surface modifier  110  and slot  105  in a tongue and groove fashion.  
         [0036]    Referring to FIG. 5A, in another embodiment, the extensions  108   a ,  108   b  and the interior surfaces  109  of the slot  105  are part of a lining  111  covering the interior walls of slot  105 . In one example, lining  111  is formed by a different material than the main body  101 . Lining  111  of the slot  105  is attached to the slot via screws  117   a ,  117   b  and an epoxy  119 . Similarly, the side slots  116   a ,  116   b  and the sides of the surface modifier  110  are part of a lining  121  covering the sides of the surface modifier  110 , as shown in FIG. 5B. In one example, lining  121  is formed by a different material than the surface modifier  110 . Lining  121  of the sides of the surface modifier  110  is attached to the surface modifier via screws  123   a ,  123   b  and an epoxy  125 . Linings  111 ,  121  may be manufactured by a variety of materials including among others metal, plastic, composites and wood.  
         [0037]    Referring to FIG. 6A and FIG. 6B, the surface modifier  110  can be inserted and attached to the bottom surface  104  of the ski  100  having either rough surface  112  or smooth surface  113  facing the outside of the ski. The configuration of FIG. 6A where the rough surface  112  of the surface modifier  110  is facing the outside of the bottom ski surface  104  is appropriate for skiing uphill, whereas, the configuration of FIG. 6B where the smooth surface  113  of the surface modifier  110  is facing the outside of the bottom ski surface  104  is used for downhill skiing.  
         [0038]    Referring to FIG. 7, in another embodiment, the surface modifier  110  covers only the central middle portion of the bottom surface  104  of the ski main body  101  and does not extend the entire length of the ski. In one example of this embodiment, the surface modifier  104  has a length  12  of 100 cm a width w 2  of 2 cm and a thickness t 2  of 0.4 cm. In this embodiment the surface modifier  110  is attached to the bottom surface  104  of the ski main body  101  by tongue and groove type attachments along the sides  140   a ,  140   b  of the surface modifier  110  and at the front end  130  of the surface modifier  110 , as shown in FIG. 8. The back end  132  of the surface modifier  110  is attached to the ski main body by a screw  128   c.    
         [0039]    Referring to FIG. 9, in yet another alternative embodiment of this invention, two surface modifiers  110   a  and  110   b  are attached to the front end  101   a  and the rear end  101   b  of the bottom surface  104  of the ski main body  101 , respectively. In one example, surface modifiers  110   a  and  110   b  have lengths  13  of 81 cm and  14  of 84 cm, respectively, and a thickness t 2  of 0.4 cm. In this example surface modifiers  110   a ,  110   b  extend to the edges of the main body  101  and cover the entire width w 1  of the bottom surface  104 .  
         [0040]    Referring to FIG. 10, the external metallic brackets  118   a ,  118   b  that form the edges of the main body  101  are also used to form the upper lips of slots  106   a ,  106   b , respectively, formed at the bottom surface  104  of the main body  101 . Slots  106   a ,  106   b , form the female surfaces and extensions  114   a ,  114   b  of the surface modifier  110   a  form the male surfaces for the tongue and groove attachment of the surface modifier  110   a  to the bottom surface  104  of the ski main body  101 . The front ends  65   a  and  66   a  of the surface modifiers  110   a ,  110   b , respectively, are also secured to the bottom surface  104  via a tongue and groove type attachment similar to the one shown in FIG. 8. The back ends  65   b  and  66   b  of the surface modifiers  110   a ,  110   b , respectively, are secured to the bottom surface  104  by screws  68   a ,  68   b , respectively.  
         [0041]    Referring to FIG. 11 and FIG. 12A, in another embodiment, surface modifier  110  comprises an elongated body extending the entire width of the bottom surface  104  and almost the entire length of the ski. Surface modifier  110  is held together on top of the bottom surface  104  of the main body  101  by brackets  118   a  and  118   b . Brackets  118   a  and  118   b  run along the sides of the ski and extend almost the entire length of the ski body  101 .  
         [0042]    Referring to FIG. 12B, in an alternative embodiment, one side  140   a  of the surface modifier  110  is attached to the bottom surface  104  of the ski main body  101  via a groove and tongue type attachment and the other side  140   b  is held together on top of the bottom surface  104  via the metallic bracket  118   b . Side  140   b  of the surface modifier  110  has an extension  114   b , which forms the male surface of the groove and tongue attachment. Side  140   a  of the surface modifier  110  is flat. The main body  101  has a side slot  106   b  formed at one of the side edges  142   b  of its bottom surface  104 . Side slot  106   b  forms the female surface for the groove and tongue attachment. The upper lip of the side slot  106   b  is formed by the metallic bracket  118   b . In order to attach the surface modifier  110  to the bottom surface  104  of the main body  101 , extension  114   b  is inserted into side slot  106   b  first, to form a groove and tongue type attachment. Next, metal bracket  118   a  is slipped over the flat side  140   a  of the surface modifier  110  and side  142   a  of the main body  101  thus holding them together. The opposite sequence is followed for detaching the surface modifier  110  from the main body  101 .  
         [0043]    Referring to FIG. 13, a method of skiing using the ski of this invention includes the following steps. In step  200  a skier is at the bottom of a hill and attaches surface modifier  110  to the bottom  104  of the ski main body  101  with the rough surface  112  facing out. Next the skier proceeds with skiing uphill  210 . When he/she arrives at the top of the hill, he/she reverses the surface modifier  110  and attaches it to the bottom  104  of the ski main body  101  with the smooth surface  113  facing out,  220 . Next, he/she proceeds with skiing downhill  230 . This process is repeated several times.  
         [0044]    Other embodiments are within the scope of the following claims. For example, surface modifier  111  may be attached to the bottom surface  104  of the ski main body  101  via a dove tail type attachment and screws. More than two screws may be used to attach surface modifier  111  to the bottom surface  104  of the ski main body  101 .  
         [0045]    Several embodiments of the present invention have been described. Nevertheless, it will be understood that various modifications may be made without departing from the spirit and scope of the invention. Accordingly, other embodiments are within the scope of the following claims.