Abstract:
The disclosure herein is directed toward systems and methods for supporting a person and enabling motion of a person across a surface of snow can while satisfying the countervailing requirements of increasing surface area for weight-carrying capacity on soft snow and reducing the opposing forces, like for example drag and friction, in hard snow. More specifically, a snowboard with improved rider support, increased speed and enhanced safety performance.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims priority to U.S. application Ser. No. 61/795,547 entitled “Snowboard” naming Nicholas James Gilson as inventor and filed Oct. 19, 2012, the contents being incorporated herein by reference in their entirety. 
    
    
     TECHNICAL FIELD 
     The systems and methods described herein relate to sporting equipment. Specifically, snowboards and other systems and methods for enabling motion of a person across a surface of snow. 
     BACKGROUND 
     Sportsmen and engineers have designed different types of snowboards to travel over the surface of the snow. Snowboards travel differently than skis and sleds. In particular, snowboards allow users to lift up on or tilt onto an edge of the board and use the force of the board&#39;s edge against the snow surface to turn direction. This type of turning is called carving and it essentially allows the skilled snowboarder to make tight radius turns. Unlike with skis, the snowboarder positions his or her feet transverse to the longitudinal axis of the board. This means that the snowboarder must lean forward or backwards to tilt the board on to one of its edges. This takes quite a bit of skill to achieve, but the benefit is that the snowboard turns using a process that keeps the velocity of the board, both speed and direction, aligned with the turned patch of the snowboard. In contrast, turning without rising on to an edge, maintains the full wide bottom surface of the snowboard against the snow road forces the rider to essentially drag the bottom surface of the board until the snowboard points in the proper direction. This manner of turning is called skidding. Skidding the board slows the rider because the frictional force of the board against the snow is not aligned with the direction of travel and therefore results in a strong frictional stopping force. Frictional forces between the board and snow surface can make riding more difficult and less fun. 
     Engineers and sportsmen have endeavored to reduce the frictional forces that slow and make less stable the movement of a snowboard across the snow. 
     The interaction between the board and the snow impacts the performance of the board and rider. For example, U.S. Pat. No. 8,356,822 describes engagement devices that can attach to the bottom of a snowboard to change how it engages with the snow and performs. U.S. Pat. No. 6,193,244 discusses a snowboard having two edges on the bottom surface for contacting the snow to reduce skidding. 
     Still there remains a need for improved systems and devices for improving and altering the performance of snowboards. 
     SUMMARY 
     In general, the system is designed to support the weight of the user and to provide motion across the surface of snow. The weight-carrying capacity of snow increases with compaction. Soft, uncompact snow has a lower weight-carrying capacity than hard, compact snow. When the weight-carrying capacity of snow is exceeded, the snow compacts until it reaches the requisite weight-carrying capacity to support the applied weight. The area of contact between the system and the snow is calculated by multiplying the width of contact between the system and the snow by the length of contact between the system and the snow. The system carries the weight of the user by transferring the weight to the snow surface across the area of contact. The maximum operating speed of the system is, in part, determined by magnitude of opposing forces that occur at the area of contact between the system and the snow surface. The opposing forces may be generated by friction, drag or other forces that oppose the primary direction of travel while the system is in use. Opposing forces have a negative impact on the maximum speed of the system. 
     Conventional systems are designed for use in one of either soft snow or hard snow. In soft snow, it is desirable for the weight of the user to be supported on a large area of contact between the system and the snow, without little or no compaction required. The large area of contact places more snow under the system to support the weight of a user; it allows the user to “glide” across the surface of snow without sinking into the snow, which would increase the magnitude of opposing forces. In hard snow, it is desirable for the weight of the user to be supported on a small area of contact between the system and the snow. The small area of contact between the system and the snow reduces the magnitude of opposing forces, such as an opposing frictional force, which, in part, contributes to an increased maximum speed of the system. 
     In the design of a conventional system, the width of contact between the system and the snow is fixed. Therefore, it is not possible to substantially increase or decrease the width of contact in response to varying snow conditions. Consequently, many expert users carry more than one system; one wide system for soft snow conditions and one other narrow system for hard snow conditions. The soft snow system is significantly wider than the hard snow system. The increased width of the soft snow system increases the horizontal surface area, and increases the normal force supporting the user. A conventional system that is designed for soft-snow causes unnecessary drag and friction when operated on hard snow. 
     In addition, when operating a conventional system, the user must be careful not to operate the system in a substantially flat position. A flat position is characterized by two opposing edges of the system touching the snow simultaneously. Often, the two edges are oriented perpendicular to the primary direction of travel. When the standard system is operated in a flat position, it has the potential to pitch and/or yaw, causing an edge of the system to unintentionally catch and stop in the snow, which generally results in the rider falling down. This phenomenon is sometimes called “catching an edge” and is potentially dangerous for the rider. 
     The snowboards described here address the countervailing requirements of increasing area for weight-carrying capacity on soft snow and reducing the opposing forces in hard snow. Moreover, these snowboards reduce the likelihood of unintentionally catching an edge in the snow. 
     The system and methods disclosed herein support the weight of the user and enable motion at a high maximum speed on snow while satisfying the countervailing requirements of increasing weight-carrying capacity reducing opposing forces. Among other features, the systems includes a contoured lower surface that sinks lower in soft snow and rises higher in hard snow. The lower surface has at least two rails and a recessed region, which provide additional surface area for transferring weight to the snow. The amount of area contacting the snow adjusts based on, in part, the rider&#39;s speed, weight and the current snow conditions. The rails on the lower surface are sloped up toward the periphery of the system, which lifts the edges up from the snow surface and thereby reduces the likelihood of unintentionally catching an edge in the snow. 
     More specifically, the systems and methods described herein include, among other things, snowboards having a board with an upper surface and a lower surface and a first and second end. Typically, both the first and second ends are curved upward, to lift the ends of the board off the surface of the snow, as commonly done with snowboards. The upper surface has locations for a first binding and a second binding to allow the bindings to be arranged transverse to a longitudinal axis extending through the first and second ends. The lower surface has a first and a second rail extending along the longitudinal axis and being separated by a recess extending along the longitudinal axis. The rails and the recess all have a width, as measured transverse to the longitudinal axis of the board. The width of the recess is typically, but not necessarily, greater than the width of each respective rail and the first and second rails and the recess extend across the width of the bottom surface and substantially the length of the bottom surface of the board. 
     Optionally, the snowboard may have first and second rails that have respective interior shoulder walls having an at least 30° inclination from an axis parallel to a beam of the board. Further optionally, the snowboard may have first and second rails have a width substantially equal to one quarter the width of the bottom surface of the board. 
     Typically, but optionally, the snowboard may have one or more bindings for gripping a boot of a rider, and the binding may be arranged to position a heel of the boot over one rail and a toe of the boot over a different rail. 
     The snowboard may have first and second rails that have surfaces for contacting the snow, the surfaces being tapered to narrow in thickness from the recess to the peripheral edge of the board. Optionally, when the board rests against a flat surface, the peripheral edge of the board is raised above the flat surface. The peripheral edge may be raised between about 1 mm and 8 mm above the flat surface, or any other suitable distance. 
     In manufacture, the snowboard may have first and second rails that comprise modular bodies for being secured to the bottom surface of the board. Alternatively, the snowboard may have first and second rails that comprise rails integrally formed as part of the bottom surface of the board. 
     Further optionally, the snowboard, under typical operating conditions, has rails with a width selected to support the weight of a user, and thereby have the recessed surface apply a force less than the weight of the user, which may include no substantial force, to the surface of the snow, such that the center of the board applies little or no force to the surface of the snow and frictional forces generated against the center of the board are reduced or eliminated. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The foregoing and other objects and advantages of the invention will be appreciated more fully from the following further description thereof, with reference to the accompanying drawings wherein; 
         FIG. 1  depicts prior art snowboard designed to support and to enable motion for a person on snow; 
         FIG. 2  depicts a cross-sectional view of a prior art snowboard; 
         FIG. 3  depicts one embodiment of a snowboard designed to support and to enable motion for a person on snow; 
         FIG. 4  depicts a cross-sectional view of one embodiment of a snowboard as described herein; 
         FIG. 5  depicts a cross-sectional view of a snowboard such as the snowboard in  FIG. 4 , and placed on a snow surface of less compact snow; and 
         FIG. 6  depicts the lower surface of the snowboard of  FIG. 3  having two rails, and partially shows a rider with bindings attached to the upper surface of the snowboard. 
     
    
    
     DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS 
     Certain illustrative embodiments will now be described, including a snowboard that supports the weight of the user and enables the user to move across the surface of snow at a high speed while satisfying the countervailing requirements of increasing weight-carrying capacity and reducing opposing forces, such as opposing frictional forces. However, it will be understood by one of ordinary skill in the art that the systems and methods described herein can be adapted and modified for other suitable applications and that such other additions and modifications will not depart from the scope hereof. 
     In certain embodiments, the snowboard has a bottom surface having two rails. The two rails run the length, or substantially the length, of the snowboard and these two rails are separated by a recess, so that the two rails are arranged to place one along each side of the snowboard. The rails have a bottom surface that contacts the snow. Under certain operating conditions, such as when the snow is compact and firm enough to prevent or reduce the rails from sinking more than a few millimeters into the snow, the snowboard moves over the snow with the rails in contact with the snow surface and the recessed portion of the board spaced away from the compact snow surface. Optionally, the rails may have a tapered surface. The taper may progress from the interior side of the rail adjacent to the recess toward the peripheral edge of the board. The taper spaces the peripheral edge of the board away from a flat surface on which the rails may rest. The tapered surfaces are examples of a contoured lower surface having dual rails. 
     Among other features, the contoured lower surface may sink lower in soft snow and ride higher in hard snow. The amount of area contacting the snow adjusts based on, in part, the rider&#39;s speed, weight and the snow conditions. The rails on the lower surface may optionally be sloped up toward the periphery of the board and may reduce the likelihood of unintentionally catching an edge in the snow, and thereby improve stability. 
     DETAILED DESCRIPTION 
       FIG. 1  depicts a prior art snowboard  100  designed to support the weight of a person and to enable motion on snow. The snowboard  100  contains at least one rigid element, wherein each rigid element has an upper surface (not shown), a lower surface  203  and one or more stiffened peripheral edges  101 ( a ) and ( b ). Edges  101 ( a ) and ( b ) are located on left and right ends and, in some embodiments, may line the entire periphery of the system. Edges  101  may be made of metal, alloy or any other suitable material. 
       FIG. 2  depicts a cross-sectional detail of the prior art snowboard of  FIG. 1 . The snowboard  100  has an upper surface  201 , a lower surface  203 , and a plurality of inner-layers  202  positioned between the upper surface  201  and lower surface  203 . Edges  101 ( a ) and ( b ) are located on left and right ends, respectively. The lower surface  203  rests on the snow surface  204 . The downward force  206  is transferred through the system  100  and is balanced by the normal force  207 . 
     Upper surface  201  may be made of a glossy material, which serves as a medium to place graphic designs and also a UV protectant layer. Lower surface  203  is typically a polyethylene and serves to reduce friction between the bottom of the system and the surface of travel. Inner-layers  202  are made of hardwood placed in between layers of fiberglass. 
     During operation, the snowboard  100  reaches a physical equilibrium state wherein the normal force  207  is equal to downward force  206 . The downward force  206  is determined, in part, by weight of the person on the snowboard  100 . The normal force  207  is distributed across the snow  204  on an area snow-to-board contact (not shown), which is determined, in part, by the width of snow-to-board contact  205 . For the prior art snowboard, the width of contact  205  remains constant even as the downward force  206  increases. 
       FIG. 3  depicts one embodiment of the snowboards described herein. Specifically,  FIG. 3  depicts the lower surface of a snowboard having two rails separated by a recess. As shown, the snowboard  300  has an upper surface (not shown), a lower surface  305 , and one or more stiffened peripheral edges  304 ( a ) and ( b ), which are located on the left side and right side of the board, respectively. The peripheral edges  304   a  and  304   b  may form a single edge that surround the full periphery of the snowboard  300 . Alternatively, in other embodiments, the edges  304   a  and  304   b  are separate edges on opposing longitudinal sides of the board. The lower surface  305  is continuous across the rails  301  and a recessed region  302  is arranged between the two rails  301   a  and  301   b . In some embodiments, the board is laminated from a series of layers. Typically the layers are wood, fiberglass and/or plastic, although other materials may be employed. These form the inner structure of the snowboard  300  and the inner layers (not shown) may be contoured in a shape that is similar to that of the lower surface  305 . In other embodiments, the inner layers (not shown) may be formed as a generally flat board and the rails  301  may be distinct components of the system that are attached separately to the lower surface  305 . In either case, the contour of the lower surface  305  may be similar. When in use, the system makes contact with the snow across the width of contact  306 . 
     The dimensions of the snowboard  305  may vary, and typically will be between 90-170 cm in length as measured along a longitudinal axis extending along the length of the snowboard  305  and between 20-30 cm in width as measured along a beam axis extending perpendicular to the longitudinal axis. The snowboard  305  has a generally hourglass shape, with curved lateral sides. Typically, both the front end and the back end are curved upward to lift the ends of the snowboard off the surface of eh snow when the lower surface  305  is placed on the snow surface. Other dimensions and shapes may be used without departing from the scope of the invention. 
       FIG. 4  depicts a cross-sectional detail of one embodiment of the snowboards described herein. According to one embodiment, system  300  has an upper surface  401  and a lower surface  305 . The lower surface  305  is continuous across the left rail  301 ( a ), the recessed region  302  and the right rail  301 ( b ). Stiffened peripheral edge  304 ( a ) and edge  304 ( b ) are located at the left end and right ends, respectively. The downward force  406  is determined, in part, by weight of the person using the snowboard. The normal force  407  is distributed across the snow  404  on an area snow-to-board contact (not shown), which is determined, in part, by the width of snow-to-board contact  305 . As the downward force  406  increases, the width of contact  305  may also increase. Likewise, as the downward force  406  decreases, the width of contact  305  may also decrease. 
     In operation, the snowboards described herein adjust to varying snow conditions. In soft snow, the board sinks lower in the snow thereby increasing the width of contact  306 , which increases the normal force supporting the rider. In some soft snow conditions, the width of contact  306  may be large enough to include the entire width of the lower surface  305 , including the surface area of rails  301  and the recessed region  302 . In hard snow, the snowboard may rise toward the top of the surface and thereby decrease the area of contact  306 . In some hard snow conditions, the width of contact  306  may be small and may only include the peak of rails  301 ( a ) and ( b ) and not the surface of the recessed region  302 . For conditions in between the soft and hard, the amount of board-to-snow contact varies as needed, such that the downward force  406  is equal to the normal force  407 . 
     Turning to  FIGS. 3 and 4 , the rails  301  run the length of the board. Thus, the length of contact is not altered relative to the conventional design but the width of contact is decreased. By keeping the length of contact between the system and the snow constant, and by decreasing the width of contact between the system and the snow, the claimed system is able to attain higher speeds on snow than a conventional system. Not to be bound by theory, but the snowboard having the two rails on the bottom surface, may be faster than a conventional snowboard. For the same physical principles that a pair of skis is faster than a standard snowboard of the same length, and a catamaran is faster than a mono-hull boat of the same length. 
     Also depicted in  FIG. 4 , the twin rails  301 , may optionally not be rectangular in shape. Instead, they may be angled upwards from the peak of the rail towards the periphery of the board. Thus, the rails have a tapered surface that progresses from the interior of the board to the peripheral edge. This design feature raises the edges  304  up above the snow when the operator is initiating a turn while operating the snowboard. The raised edges allow the user to travel on width of contact  306 , without fear of unintentionally catching an edge. The result is increased comfort and, in part, safety and stability at high speeds. To initiate a carving turn, the rider must rotate the claimed system slightly further than the conventional system, ensuring that any edge-to-snow contact is intentional. 
       FIG. 5  depicts the snowboard of  FIGS. 3 and 4  placed on a snow surface that is less firm and compact than the snow surface of  FIG. 4 . Specifically,  FIG. 5  illustrates the snowboard  300  disposed over a snow surface  404 . A force  406 , typically the weight of the Rider, pushes the snowboard  300  against the snow surface  404 . In the conditions represented by  FIG. 5 , the rails  301 ( a ) and  301 ( b ) press more deeply into the snow surface  404  than under the conditions depicted by  FIG. 4 . The areas of contact  306 ( c ) and  306 ( d ) of the rails  301 ( a ) and  301 ( b ) against the snow  404  are larger than the areas of contract  306 ( a ) and  306 ( b ) depicted in  FIG. 4 . In still less firm conditions, the snow  404  may contact the recessed region  302  and press against the snowboard  302 , at the rails  301 ( a ) and  301 ( b ) and at the recessed regions. 
       FIG. 6  depicts the lower surface  305  of the snowboard  300  and partially depicts binders and boots of a rider. As shown, the binders or bindings grip the rider&#39;s boot and hold the boot on the upper surface of the snowboard  300 . The binding is arranged to position the heel of the boot  602  over one rail  301   b  and a toe of the boot (not shown) over a different rail  301   a . To turn, the rider can lean forward or back to tip the snowboard  300  onto an edge  304  to carve a turn into the snow. 
     The manufacture of the disclosed snowboard may be accomplished employing methods that are familiar to those skilled in the art. For example, the layers of the disclosed snowboard may be constructed, in part, using a mold, which is designed having a shape consistent with the contours of the claimed system. Other example manufacturing methods may have an expandable bladder, placed in an enclosure with the layers of the system and the mold. As the bladder expands, it applies pressure to the layers, forcing them against the mold and imparting the contours of the mold. In some embodiments of a manufacturing system struts, made of wood, are used to help distribute the pressure from the bladder to the layers of the system. In other embodiments of a manufacturing method, the layers of the system may be pressed together using a pneumatic press, which applies pressure to the layers, forcing them against the opposing surface of the press and imparting the contours of the claimed system. In other embodiments, the layers of the system are attached to one another using adhesives, epoxy, or other suitable attachment systems. 
     Those skilled in the art will know or be able to ascertain using no more than routine experimentation, many equivalents to the embodiments and practices described herein. For example, the claimed system and the knowledge disclosed herein may be utilized to modify or to create systems designed to carry a person or objects across a surface of water, sand, or other materials. More specific example applications may include, among other things, snowboards, water skis, wake boards, kayaks, winder surfers, or paddle boards. 
     Accordingly, it will be understood that the invention is not to be limited to the embodiments disclosed herein, but is to be understood from the following claims, which are to be interpreted as broadly as allowed under the law.