Patent Publication Number: US-6702315-B2

Title: Methods and apparatus for resisting gliding device runaway

Description:
FIELD OF THE INVENTION 
     This invention relates to methods and apparatus for resisting gliding device runaway. 
     BACKGROUND OF THE INVENTION 
     Runaway of a gliding device, such as a ski or snowboard, that occurs when the gliding device is separated from a rider can be a problem, particularly on steep, well-groomed ski trails. For example, an unrestrained ski that becomes separated from a skier, e.g., when the skier falls and the ski binding releases the skier&#39;s boot, may travel at high speed down the ski slope once liberated and cause injury or damage. 
     Various restraining devices, such as straps or leashes that connect a ski to the skier&#39;s leg or boot, or ski brakes, have been used to resist ski runaway. Commonly-known ski brakes operate so that braking arms are retracted when the skier&#39;s boot is secured to the ski by the ski bindings. When the bindings release the ski boot, the arms extend below the ski base to resist travel of the ski. In many ski brake designs, the skier&#39;s boot depresses a pedal as the boot is engaged by a heel binding causing the braking arms to be retracted. Release of the boot by either the heel or toe binding frees the pedal from contact with the ski boot, and allows the braking arms to extend below the ski base. 
     SUMMARY OF THE INVENTION 
     Embodiments in accordance with various aspects of the invention provide a braking feature that resists gliding device runaway. In one aspect of the invention, the gliding device does not include any foot bindings or other device to secure a rider&#39;s feet or other body portion to the gliding device. Thus, various aspects of the invention may be useful in preventing runaway of gliding devices that do not use bindings to secure a rider to the device, such as a snowdeck, snowskate, sled, skateboard, etc. 
     In one aspect of the invention, a gliding board includes an upper surface constructed and arranged to support a rider&#39;s feet while the rider is standing without a binding to secure at least one foot to the upper surface, and a bottom surface constructed and arranged to contact a gliding surface. A braking feature is always in an active state to resist movement of the gliding board along the gliding surface. This is in contrast, for example, to a conventional ski brake that is put into an inactive state and does not resist movement of the ski when a ski boot is engaged with the ski binding. 
     In another aspect of the invention, a gliding device includes an upper surface constructed and arranged to support a rider&#39;s feet while the rider is standing without a binding to secure at least one foot to the upper surface, and a bottom surface adapted to contact a gliding surface. A braking feature resists movement of the gliding board along the gliding surface when the rider is not supported by the upper surface. 
     In another aspect of the invention, a gliding device for supporting a rider when sliding on a surface includes a runner having an upturned end, a middle portion and a bottom surface that contacts a gliding surface. A deck is elevated from the runner, and has an upper surface that supports a rider and a longitudinal axis. A spacer is secured to the runner and to the deck so that forces applied by a rider on the deck are transmitted to the runner, and a braking feature is adapted to resist movement of the gliding device sliding on the gliding surface. 
     In another aspect of the invention, a gliding device for supporting a rider when sliding on a surface includes a runner having an upturned end, a middle portion and a bottom surface that contacts a gliding surface. A deck is elevated from the runner, and has an upper surface that supports a rider and a longitudinal axis. A spacer is secured to the runner and to the deck so that forces applied by a rider on the deck are transmitted to the runner. A braking feature adapted to resist movement of the gliding device sliding on the gliding surface may be controlled based on a force urging the bottom surface into contact with the gliding surface. 
     In another aspect of the invention, a gliding device for supporting a rider when sliding on a surface includes a runner having an upturned end, a middle portion and a bottom surface that contacts a gliding surface. A deck is elevated from the runner, and has an upper surface that supports a rider. A spacer is secured to the runner and to the deck so that forces applied by a rider on the deck are transmitted to the runner. A braking feature adapted to resist movement of the gliding device sliding on the gliding surface may be controlled based on a separation distance between a portion of the deck and a portion of the runner. 
     In another aspect of the invention, a gliding device for supporting a rider when sliding on a surface includes a runner having an upturned end, a middle portion and a bottom surface that contacts a gliding surface. A deck is elevated from the runner, and has an upper surface that supports a rider. A spacer is secured to the runner and to the deck so that forces applied by a rider on the deck are transmitted to the runner, and a braking feature adapted to resist movement of the gliding device sliding on the gliding surface may be deactivated by an adjustable deactivation force. 
     In other aspect of the invention, a gliding device for supporting a rider when sliding on a surface includes a runner having an upturned end, a middle portion and a bottom surface that contacts a gliding surface. A deck is elevated from the runner, and has an upper surface that supports a rider. A spacer is secured to the runner and to the deck so that forces applied by a rider on the deck are transmitted to the runner. A braking feature includes a braking element adapted to resist movement of the gliding device sliding on the gliding surface, and a delay element adapted to delay activation of the braking element for a period of time after the rider is no longer supported by the deck. 
     In another aspect of the invention, a gliding device for supporting a rider when sliding on a surface includes a runner having an upturned end, a middle portion and a bottom surface that contacts a gliding surface. A deck is elevated from the runner, and has an upper surface that supports a rider and a longitudinal axis. A spacer is secured to the runner and to the deck so that forces applied by a rider on the deck are transmitted to the runner. Braking means are provided for resisting movement of the gliding device on the gliding surface. 
     In another aspect of the invention, a method for resisting movement of a gliding device includes providing a gliding device having a runner with a bottom surface that contacts a gliding surface, a deck elevated from the runner, and a spacer secured to the runner and to the deck so that forces applied by a rider on the deck are transmitted to the runner. Movement of the gliding device on the gliding surface may be resisted by engaging a portion of the gliding device with the sliding surface. 
     These and other aspects of the invention will be apparent from the following description and appended claims. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Illustrative embodiments are described in connection with the following drawings, in which like numerals reference like elements, and wherein: 
     FIG. 1 is a perspective view of a snowdeck in an illustrative embodiment in accordance with an aspect of the invention; 
     FIG. 2 is an end view of a snowdeck having a braking feature that tilts the snowdeck about a longitudinal axis; 
     FIG. 3 is an end view of a snowdeck having a hinge connection between the top deck and runner; 
     FIG. 4 is a side view of a snowdeck having a resilient member that resists contact of the runner base with a sliding surface; 
     FIG. 5 is a perspective bottom view of a snowdeck having a resilient member similar to that shown in FIG. 4; 
     FIG. 6 is a side view of a snowdeck having the resilient member shown in FIG. 5 in a weighted condition; 
     FIG. 7 is a perspective view of a snowdeck having a resilient member extending laterally from the runner; 
     FIG. 8 is a sectional side view of a plunger-type braking device in accordance with one aspect of the invention; 
     FIG. 9 is a side view of another braking device in accordance with an aspect of the invention; 
     FIG. 10 is a perspective view of the braking device shown in FIG. 9; 
     FIG. 11 is a side view of another braking device in accordance with an aspect of the invention; 
     FIG. 12 shows a side view of a snowdeck including the braking device shown in FIG. 11; 
     FIG. 13 is a side view of a snowdeck with a braking feature in the form of a high degree of reverse camber in the runner; 
     FIG. 14 is a side view of a snowdeck having a braking device that operates in accordance with a separation between the top deck and the runner; 
     FIG. 15 shows an illustrative embodiment of a braking device that operates in accordance with top deck and runner separation; 
     FIG. 16 shows an illustrative embodiment of a braking device that operates based on separation of a top deck portion and the runner in a snowdeck and has a brake deployment delay feature; 
     FIG. 17 is a perspective view of a snowdeck having a top deck portion that is depressible to disengage a braking device; 
     FIG. 18 is a perspective view of another illustrative embodiment of a braking device in accordance with an aspect of the invention; 
     FIG. 19 is a schematic diagram of a snowdeck having a braking device that is activated based on a signal from a remote transmitter; and 
     FIG. 20 is a schematic block diagram of an electronically-controlled braking device. 
    
    
     DETAILED DESCRIPTION 
     Illustrative embodiments in accordance with various aspects of the invention are described below. Although several of the illustrative embodiments are described in connection with a snowdeck, such as that shown in FIG. 1, several of the illustrative embodiments and various aspects of the invention may be used with other gliding devices, such as skis, snowboards, sleds, snow scooters, skateboards, and other devices used for gliding on snow, ice, asphalt, sand, grass or other suitable surfaces. 
     In some aspects of the invention, the inventors have developed braking features to resist gliding board movement on a gliding surface where the gliding board does not include foot bindings or other devices to physically attach a rider to the gliding device. Conventional braking devices may rely on the detachment of a rider from the binding device to activate the braking device. The inventors have found that such devices are not useful for gliding devices, such as a snowdeck, that does not include foot bindings. Although straps, tethers or other devices have been used to attach a rider to a gliding device, a gliding device such as a snowdeck presents a special problem because riders perform tricks in which the rider&#39;s feet move on the snowdeck or are intentionally separated at least momentarily from the snowdeck. A strap or tether that connects the rider&#39;s leg or other body portion to the snowdeck may potentially interfere with such tricks. Thus, in some cases a braking feature that prevents movement of the gliding device without a tether or other physical connection between the rider and the gliding device may be preferable. Although various aspects of the invention described herein may be used with gliding devices having no foot bindings or similar devices, these aspects of the invention may be useful in gliding devices that have foot bindings or other devices that attach a rider to the gliding device. 
     Illustrative embodiments in accordance with various aspects of the invention described below include a gliding device, such as a snowdeck, that has a braking feature to resist runaway of the gliding device. The braking feature may resist gliding of the device with and/or without a rider using the gliding device. For example, the presence of the rider using the gliding device may deactivate the braking feature which then becomes effective when the rider is no longer mounted on the gliding device, e.g., the rider falls and becomes separated from the gliding device. Alternately, the braking feature may always be in an active state to resist gliding, but the braking feature&#39;s resistance to gliding may be overcome by a force of the rider, e.g., a force of gravity on the rider, to move the gliding device along a gliding surface. 
     In one aspect of the invention, the braking feature included with the gliding device may be a physical feature or condition of the gliding device. For example, “fish scale” features or similar features on the base or other bottom surface of the gliding device may resist movement on a gliding surface. Alternately, the gliding device may be arranged to tilt on its side or turn over without the presence of a rider. Tilting of the gliding device may cause portions of the device to contact the gliding surface and resist movement on the gliding surface. In contrast, the braking feature may include active braking devices that resist gliding movement of the device. For example, the braking feature may include one or more braking arms that depend below the base or other gliding surface of the gliding device. The braking arm(s) may be resilient to resist movement of the gliding device, yet still allow relatively unimpeded use of the gliding device by a rider. The braking arm(s) may be retractable, e.g., de-activated by the rider&#39;s weight on the gliding device, to allow unimpeded riding. The braking arm may be deployed once the rider is no longer suitably positioned on the gliding device, and in some cases deployment of the braking arm can be delayed, e.g., to prevent brake activation while a rider is momentarily separated from the device during a trick or other maneuver. 
     FIG. 1 shows an illustrative embodiment of a snowdeck in accordance with an aspect of the invention. In this embodiment, the snowdeck  1  includes a deck  2  that is attached to, and vertically spaced from, a runner  3  by spacers  4 . The snowdeck  1  may be maneuvered in much the same way as a conventional skateboard, e.g., the rider may turn the snowdeck  1  by tilting the snowdeck  1  about its longitudinal axis. The snowdeck  1  and its various component parts may be constructed and/or arranged in any suitable way, such as that described in U.S. patent application Ser. No. 09/733,626, filed Dec. 8, 2000, which is hereby incorporated by reference in its entirety. 
     In one aspect of the invention, a braking feature may be a passive feature that includes no moving parts, and includes one or more design features of the gliding device. For example, FIG. 2 shows a sectional end view of a snowdeck  1  having a braking feature in which the snowdeck  1  is arranged to tilt about a longitudinal axis when a rider is not supported on the upper surface of the deck  2 . In this embodiment, the center of gravity of the snowdeck  1  is arranged outboard of a lower edge  31  of the runner  3  so that when the rider is not supported on the deck  2 , the snowdeck  1  rotates, or tilts, about the lower edge  31 . When the rider is positioned on the deck  2 , the center of gravity of the rider/snowdeck combination may be positioned between the lower edges  31  of the runner  3  so that the snowdeck  1  may be ridden without substantial interference of the tendency of the snowdeck  1  to tilt. Tilting of the snowdeck  1  urges the bottom surface of the runner  3  out of contact with a gliding surface  10  and causes a lateral edge  21  of the deck to contact the gliding surface  10  and/or the snowdeck  1  to flip over onto the deck  2 . Contact of the lateral edge  21  of the deck  2  with the gliding surface  10  may create friction between the gliding surface  10  and the deck  2  that slows or stops movement of the snowdeck  1  along the gliding surface  10 . Tilting of the snowdeck  1  may also cause the snowdeck  1  to turn, e.g., because of the frictional force on the lateral edge  21  and/or a sidecut or other feature of the lower edge  31  that is in contact with the gliding surface  10 . Movement of the snowdeck  1  may be resisted by a combination of turning caused by the snowdeck  1  riding on the lower edge  31  as well as frictional contact between the lateral edge  21  of the deck  2  with the gliding surface  10 . The lateral surface  21  may include barbs or other friction-enhancing features to resist movement of the snowdeck  1 . 
     Tilting of the snowdeck  1  may be caused in any suitable way. In the embodiment shown in FIG. 2, the deck  2  includes a weighted portion  22  that tends to cause the snowdeck  1  to tilt around the lower edge  31  of the runner  3 . The weight and/or arrangement of the weighted portion  22  tends to tilt the snowdeck  1  when no rider is on the deck  2 , but preferably does not significantly degrade the riding characteristics, such as the turning response or stability of the snowdeck  1 . The weighted portion  22  can take any suitable shape or size, and be positioned in any suitable way in or on the snowdeck  1 . For example, the weighted portion  22  may be embedded within the deck  2 , attached to the runner  3  or spacer  4 , etc. Thus, the weighted portion  22  need not necessarily be a separate component from the deck  2 , spacer  4  or runner  3  and may be a portion of the deck  2 , etc. that is suitably positioned to cause the snowdeck  1  to tilt. Therefore, the only requirement for the weighted portion  22  is that the center of gravity of the snowdeck  1  be shifted to a position outboard of one of the lower edges  31  or other pivot point for the snowdeck  1 . 
     In another illustrative embodiment, the bottom surface of the runner  3  may include “fish scale” or other surface features to resist runaway or other movement. The term “fish scale” features refers to the type of features found on the runner portion of some waxless cross country skis that provide the ski with grip when climbing an inclined snow slope. The size, orientation and configuration of the fish scale features can vary widely depending on various factors, such as the size and weight of the runner  3  and/or snowdeck  1 . For example, fish scale features may be arranged at the contact areas of the runner  3  so that they provide a different resistance to gliding when the snowdeck  1  is moved in different directions. That is, the fish scale features at one end of the snowdeck  1  may provide a maximum resistance to gliding when positioned at the rear end of the snowdeck  1  during travel, and less resistance to gliding when positioned at the forward end during travel. Of course, any surface feature or combination of features may be used that provides a sufficient resistance to gliding board movement, e.g., to resist runaway. Preferably, the surface features provide a resistance to movement that does not substantially affect the performance of the gliding device, and in some cases may enhance its performance. For example, fish scale features at the contact areas of the runner  3  may provide a snowdeck  1  with an improved ability to move in a straight line path during riding. 
     In an alternate embodiment, one or more portions of the snowdeck  1  may be arranged to move relative to other portions of the snowdeck  1  and thereby activate a braking feature. For example, FIG. 3 shows an embodiment in which the spacers  4  include a hinge  41  that interconnects the deck  2  and the runner  3 . The hinge  41  may be spring-biased so that when a rider is not supported by the deck  2 , the hinge  41  biases the deck  2  to rotate away from the runner  3 . This rotation may cause a lateral edge  21  of the deck  2  to contact the gliding surface  10  and resist movement of the snowdeck  1 . Movement of the deck  2  relative to the runner  3  may also, or alternately, shift a center of gravity of the snowdeck  1  so that the snowdeck  1  tends to tilt or flip over in a manner similar to that in the FIG. 2 embodiment. The spring bias in the hinge  41  is preferably sufficient to move the deck  2  relative to the runner  3 , but not strong enough to substantially resist the weight of a rider. Thus, when a rider is supported on the deck  2 , the hinge  41  closes to a riding position, e.g., where the upper surface of the deck  2  and the bottom surface of the runner  3  are approximately parallel. 
     In some cases, the hinged connection between the deck  2  and the runner  3  may hamper a rider&#39;s ability to maneuver the snowdeck  1 . For example, when a rider attempts to tilt the snowdeck  1  to initiate a turn, the hinge  41  may rotate and prevent transfer of the tilting force of the rider&#39;s feet to the runner  3 . To counteract this tendency, the snowdeck  1  may instead have a relatively stiff connection between the deck  2  and the runner  3  similar to that in the FIG. 2 embodiment. Braking may be provided by a portion of the deck  2  or other braking member that is pivotally mounted to the deck  2  by a hinge  41 . For example, the deck  2  may be split into two stacked portions that are attached together by a spring-biased hinge  41 . The lower deck portion may be rigidly connected to the runner  3  by the spacers  4  while the upper deck portion or other braking member is hinged to the lower deck portion. The upper deck portion or other braking member may be rotated to lie flat on the deck  2  or within recesses in the deck  2  and held in place against the spring bias of the hinge  41  by the rider&#39;s feet during riding. When the rider is no longer supported on the upper surface of the deck  2 , e.g., if the rider falls, the hinged portions may rotate under the spring bias of the hinge  41  away from the lower deck portion to activate a braking feature. Rotation of the hinged portions may shift the snowdeck&#39;s center of gravity and cause the snowdeck  1  to tilt and/or the upper deck portion or other braking member may rotate to contact the gliding surface  10  and resist gliding movement. As a result, a rigid connection may be maintained between the deck  2  and the runner  3  to provide responsive turning characteristics while also providing a braking feature. 
     Alternately, the hinge  41  in the FIG. 3 embodiment may be selectively locked in a riding position to allow the rider to transfer tilting force to the runner  3  during riding, and unlocked to allow the braking feature to be activated. For example, the hinge  41  in the FIG. 3 embodiment may include hinge plates having holes  42  to receive a retaining pin (not shown). Thus, when the deck  2  is rotated toward the runner  3 , the holes  42  may be aligned and the retaining pin inserted through the aligned holes  42 . Once the pin is in place, rotation of the deck  2  relative to the runner  3  is prevented until the pin is withdrawn. The pin may be attached to a rip-cord or other tether and pulled from the holes  42  if the rider falls from the snowdeck  1  during riding. For example, the rip-cord may be attached to the rider&#39;s leg or hand so that if the rider is separated from the snowdeck  1 , the attached rip-cord pulls the pin from the holes  42 . 
     In another illustrative embodiment, a gliding device may include one or more resilient braking elements that urge at least a portion of the bottom surface of the gliding device away from the gliding surface or otherwise contact a gliding surface to resist movement of the snowdeck. A resilient braking element may be attached to the gliding device and contact the gliding surface, thereby creating a frictional force that resists gliding. The braking element may be active with and/or without the presence of the rider. If the braking element is active while the rider uses the gliding device, the frictional force of the resilient braking element may be overcome by the force of a rider, e.g., the force of gravity on the rider pulling the rider and the gliding device down a gliding surface. 
     FIG. 4 shows a side view of an illustrative embodiment including a resilient portion  5  that is attached to the deck  2  and extends below the bottom surface of the runner  3 . The resilient portion  5  may be made of any suitable material such as a plastic, metal, rubber or other material or combination of materials with suitable properties. The resilient portion  5  may have sufficient strength to urge the bottom surface of the runner  3  away from the gliding surface  10  and thereby resist movement of the snowdeck  1  along the gliding surface  10 . The resilient portion  5  may have sufficient strength and length to tilt the snowdeck on its side, e.g., to a position similar to that shown in FIG.  2 . Alternately, the resilient portion  5  may not necessarily have sufficient strength to lift the snowdeck  1  off of the gliding surface  10 , but instead have barbs, spurs or other features that are resiliently urged against the gliding surface  10  to resist movement of the snowdeck  1 . If the resilient portion  5  has sufficient strength to lift the snowdeck  1  off of the gliding surface  10 , the resilient portion  5  preferably does not have sufficient strength to substantially resist the weight of a rider on the deck  2 . That is, once a rider is supported on the deck  2 , the resilient portion  5  deforms to allow the runner  3  to contact the gliding surface  10 . In any case, the resilient portion  5 &#39;s resistance to movement of the snowdeck  1  along the gliding surface  10  may be sufficient to prevent a runaway snowdeck  1 , but not sufficient to significantly affect the riding performance of the snowdeck  1 . 
     FIG. 5 shows a perspective bottom view of a snowdeck  1  having a strap-type resilient portion  5 . In this illustrative embodiment, a resilient strap that forms the resilient portion  5  is attached at its ends to the deck  2  so that the mid-portion of the strap is supported away from the deck  2  at a position below the bottom surface of the runner  3 . FIG. 6 shows a side view of the FIG. 5 embodiment when the snowdeck  1  is supporting the weight W of a rider on the deck  2 . The weight W of the rider deforms the resilient portion  5  so that the runner  3  may contact the gliding surface  10 . As with the FIG. 4 embodiment, the portion of the resilient portion  5  that contacts the gliding surface  10  may include spikes, barbs or other features that tend to resist movement of the snowdeck  1  along the gliding surface  10 . The spikes, barbs or other features may be molded into a plastic strap, or may be otherwise attached to the resilient portion  5 , e.g., by rivets or other mechanical fasteners. When the snowdeck  1  is unweighted, the resilient portion  5  may elastically recover to a shape near that shown in FIG.  5  and optionally urge the bottom surface of the runner  3  away from the gliding surface  10 . Since the snowdeck  1  may be constructed and arranged to be ridden in either direction, e.g., either toward the left or right as shown in FIG. 6, the resilient portion  5  may be suitably arranged to accommodate the variety of ways that the snowdeck  1  may be ridden. The resilient portion  5  may include preferential folds, bends or other features that present a relatively smooth surface on the gliding surface  10  when the rider is supported on the snowdeck  1  so that the resilient portion  5  minimizes its resistance to gliding. However, when the snowdeck is unweighted, the resilient portion  5  may unfold or otherwise recover to present a braking surface, such as one including spurs, barbs, etc., on the gliding surface  10 . For example, the peak of the resilient portion  5  in its undeformed state shown in FIG. 5 may include spikes, while parts of the resilient portion away from the peak have a relatively smooth surface. Thus, when the resilient portion  5  is deformed as shown in FIG. 6, a smooth surface rather than the spikes at the peak are in contact with the gliding surface  10 . When the snowdeck  1  is unweighted, the resilient portion  5  may recover and force the spikes into contact with the gliding surface  10 . 
     The resilient braking element need not necessarily be secured to the deck  2  as shown in FIGS. 4-6, but may be secured to other portions of the snowdeck  1 . For example, the illustrative embodiment shown in FIG. 7 includes a resilient portion  5  that is secured to the runner  3  and extends laterally outward and downward from the runner  3 . In this embodiment, the resilient portion  5  extends below the bottom surface of the runner  3  to resist movement of the snowdeck  1 . As in other embodiments, the resilient portion  5  may urge the snowdeck  1  away from contact with a gliding surface  10  when a rider&#39;s weight is not supported on the deck  2 . The ends of the resilient portion  5  that contact the gliding surface  10  may also have barbs, spikes or other features to resist movement, and the resilient portion  5  may be made of any suitable material or combination of materials. The resilient portion  5  may be secured to the runner  3  in any suitable way, such as by screws, adhesive or any other mechanical fastener. As in the other embodiments, the resilient portion  5  may also be formed integrally with any portion of the snowdeck  1 , such as the spacers  4 , the runner  3  or the deck  2 . 
     FIG. 8 shows another illustrative embodiment of a braking device in accordance with an aspect of the invention. In this illustrative embodiment, a braking element  61  is biased in a downward direction by a spring  62  within a housing  63 . The housing  63  may be fastened to an upper surface of the runner  3  over a hole  32  formed in the runner  3 . Thus, the spring  62  can urge the braking element  61  against the gliding surface  10  to resist movement of the snowdeck  1  along the gliding surface  10 . In this embodiment, the braking element  61  has a conical end  611  that engages the gliding surface  10  to resist movement. However, the braking element  61  may have any suitable shape. For example, the braking element  61  may have a skeg-type shape that engages the gliding surface  10 . That is, the braking element  61  may include a blade-like portion that is oriented in a longitudinal direction along the snowdeck  1 , and may be biased to move in a downward direction to resist runaway of the snowdeck  1 . In addition, the blade or skeg portion may also provide ride stability, e.g., the blade or skeg portion may cause the snowdeck  1  to travel in a more straight-line path during riding than if the skeg or blade were not present. Similar to the braking element  61  shown in FIG. 8, a braking element  61  having a blade or skeg-like shape may be spring-biased to move vertically relative to the runner  3 , or may be biased about a pivot point. The blade or skeg may be positioned near the contact areas, i.e., near the transition from upturned ends of the runner  3  to the running length of the runner  3 , to have more effect on ride stability. The blade or skeg portion may have any suitable dimensions, e.g., 1-15 cm long, 1-10 mm wide and 1-30 mm high, and made of any suitable material, such as plastic, metal and/or a composite material. In at least one alternate embodiment, blades or skegs may be provided at both contact areas on the runner  3  and may be fixed in place rather than spring-biased to move relative to the runner  3 . 
     Although the embodiment shown in FIG. 8 depicts a braking device  6  that is positioned away from a spacer  4 , the braking device  6  may be formed integrally with one or more spacers  4  on the snowdeck  1 . That is, the housing  63  may be formed by a part of the spacer  4  within which the spring  62  and the braking element  61  may be positioned. Although such a feature is not shown, the braking element  61  may include a shoulder or other portion that prevents the braking element  61  and the spring  62  from passing completely through the hole  32  and the runner  3  and/or from extending more than a desired distance below the bottom surface of the runner  3 . 
     In another aspect of the invention, a braking feature may be deactivated by sufficient force urging the gliding device into contact with a gliding surface. The force urging the gliding device into contact with the gliding surface may be the weight of the rider on the gliding device. Once the force is removed, e.g., the rider is no longer supported by the gliding device, the braking feature may be activated. For example, FIGS. 9 and 10 show a side view and a perspective view of another braking device in an illustrative embodiment. In this embodiment, the braking device  6  includes a frame  64  that is pivotally mounted to the runner  3  at a hinge  65 . The hinge  65  may be spring-biased so that the frame  64  is biased to rotate in a counterclockwise direction relative to the runner  3  as shown in FIG.  9 . The frame  64  includes a pair of arms  66  extending downwardly from the frame  64  and a pair of braking elements  61  attached at an end of the frame  64  opposite the hinge  65 . When the weight of a rider is supported on the snowdeck  1 , the bottom surface of the runner  3  moves toward the gliding surface  10 , which presses upwardly on the arms  66  and rotates the frame  64  so that the braking elements  61  are disengaged from the gliding surface  10 . However, when the rider&#39;s weight is not supported on the snowdeck  1 , the spring force of the hinge  65  rotates the frame  64  to a position approximately like that shown in FIG. 9, thereby engaging the braking elements  61  with the sliding surface  10 . 
     The braking elements  61  and other portions of the braking device  6  may be formed in any suitable way to provide the desired braking features. For example, the braking elements  61  may be attached to the frame  64  so that the braking elements  61  may rotate relative to the frame  64 . This rotation may be provided by a pivoting connection, or by the resilient twisting or other deformation of the braking elements  61  or the frame  64 . A flexible sheet  67  may be provided under the arms  66  and connected to the runner  3  to minimize or prevent any braking action provided by the arms  66  as a result of the gliding surface pushing upward on the arms  66 . The sheet  67  may be a flexible plastic material that is secured to the bottom surface of the runner  3  and separates the arms  66  from the gliding surface  10 . Alternately, the ends of the arms  66  that contact the gliding surface may be rounded or otherwise made to minimize any frictional force on the arms in a direction transverse to the direction of movement of the arms  66  relative to the runner  3 . As with the other embodiments described herein, the braking device  6  may be made of any suitable materials using any suitable construction technique. For example, the frame  64 , arms  66  and braking elements  61  may be molded as a single, unitary member, or assembled from separate parts. Spring bias provided at the hinge  65  may be supplied by a compression or torsion spring, or by elastic deformation of the frame  64  or other portion of the hinge  65 . In this embodiment, the arms  66  are shown extending through holes in the runner  3 , while the braking elements  61  extend below the runner  3  at opposite lateral edges. Alternately, the braking elements  61  may extend through holes in the runner  3 , or the arms  66 , as well as the braking elements  61  may be positioned outside the lateral edges of the runner  3 . 
     In another aspect of the invention, a braking element in a braking device may move transversely relative to a gliding surface to activate and deactivate a braking feature or otherwise change the braking device&#39;s resistance to movement of the gliding device. For example, FIGS. 11 and 12 show a side view of yet another braking device  6  in accordance with an aspect of the invention. In this embodiment, the braking device  6  includes a frame  64  having a “V”-shaped slot  641 . The frame  64  is mounted to the runner  3  and a braking element  61  may travel along the V-shaped slot  641 . Thus, if force is placed on the braking element  61  in a direction generally from left to right, the braking element  61  may travel up the V-shaped slot  641  toward the right. Conversely, if force is directed generally on the braking element  61  from right to left, the braking element  61  may travel to the left up the slot  641 . A spring return (not shown) or other similar feature may be provided so that the braking element  61  is urged toward the bottom portion of the V-shaped slot  641  as shown in FIG.  11 . Thus, for example, when the braking device  6  is mounted to a snowdeck  1 , as shown in FIG. 12, the spring bias on the braking element  61  may cause the element  61  to engage the sliding surface  10  to resist movement of the snowdeck  1 . When a rider is supported on the snowdeck  1 , force of the gliding surface  10  on the braking element  61  may cause the braking element  61  to travel up one of the portions of the V-shaped slot  641  so that braking element  61  provides little or no resistance to movement of the snowdeck  1 . In addition to, or instead of moving within the V-shaped slot  641 , the braking element  61  may be mounted to rotate about a pivot point above the bottom surface of the runner  3 . As with other embodiments described above, the braking element  61  may resiliently rotate under a spring or other resilient bias so that a rider may use the snowdeck  1  relatively unimpeded by the braking element  61 , but so that the braking element  61  resists runaway of the snowdeck  1 . The braking element  61  and other portions of the braking device may be made of any suitable material, such as metal or plastic, and may have spurs, barbs or other features to enhance or otherwise control the braking resistance of the device  6 . 
     In another aspect of the invention, a braking feature may include passive structural features of the gliding device, but unlike the FIG. 2 embodiment, the passive structural feature may include a movable portion. For example, FIG. 13 shows a snowdeck  1  having a runner  3  with a high degree of reverse camber, i.e., the runner  3  has a relatively high radius of curvature along its length. When a rider is supported on the deck  2 , the runner  3  is sufficiently flexible to flatten under the rider&#39;s weight to provide the desired riding characteristics, such as turning capability and stability. However, when a rider&#39;s weight is not supported on the deck  2 , the runner  3  returns to its curved shape. In this configuration, the curvature of the runner  3  can cause the snowdeck  1  to become unstable, and thus to tip over, thereby resisting snowdeck runaway. The degree of curvature of the runner  3  can be any suitable value or set of values so that the desired braking or other resistance to movement is provided. In addition, the reverse camber of the runner  3  may be combined with any other suitable braking features. For example, the runner  3  may also be curved in a lateral direction in addition to, or instead of being curved in a longitudinal direction as shown in FIG.  13 . Curvature in the lateral direction may cause the snowdeck  1  to roll over or tilt when the rider is not supported on the deck  2 . 
     In another illustrative embodiment, a braking feature may be controlled based on a distance between at least a portion of an upper surface that supports a rider and a lower surface that contacts a gliding surface. For example, FIG. 14 shows a snowdeck  1  having at least one spacer  4  that allows the deck  2  and the runner  3  to move toward and away from each other. For example, the spacers  4  may include a spring-supported suspension system. Each of the spacers  4  may include a hinged connection between the deck  2  and the runner  3  that allows the deck  2  and runner  3  to move toward each other. A compression spring may also be provided at each spacer  4  to urge the deck  2  and runner  3  to return to an initial separation distance. Of course, a hinged suspension arrangement such as that shown in FIG. 14 is only one example of spacer arrangements that provide a suspension-type function. For example, the spacers  4  may include spring-biased telescoping elements that allow the deck  2  and runner  3  to move toward and away from each other, a swing arm or torsion bar suspension system or other suitable arrangement. 
     In this illustrative embodiment, the braking device  6  operates so that when the rider&#39;s weight is not supported on the deck  2 , the spacers  4  including a suspension feature urge the deck  2  and runner  3  to move away from each other, thereby activating the braking device  6 . However, when the rider&#39;s weight is supported on the top deck  2 , the spacers  4  allow the deck  2  and the runner  3  to move toward each other, thereby deactivating or otherwise reducing the braking function of the braking device  6 . 
     FIG. 15 shows an illustrative embodiment of a braking device  6  that may be used in the FIG. 14 embodiment. In this embodiment, a link  68  is secured to the deck  2  and pivotally attached to one end of a lever  69 . The lever  69  is pivotally attached to a hinge  65  near a mid-region of the lever  69  and is pivotally attached to a braking element  61 . As the deck  2  moves toward the runner  3 , the link  68  causes the lever  69  to rotate about its pivotal attachment point to the hinge  65 . Rotation of the lever  69  lifts the braking element  61  relative to the runner  3 , thereby deactivating the braking element  61 , or otherwise reducing its resistance to motion of the snowdeck  1  on a gliding surface  10 . As a result, while a rider is supported on the deck  2 , the braking device  6  may be deactivated, but again activated once the rider is no longer supported on the deck  2 . 
     In another illustrative embodiment, activation of a braking device may be delayed, e.g., to allow a rider to perform tricks and other maneuvers in which the deck is substantially unweighted for a relatively short period of time and then again weighted. For example, a rider may jump up off the snowdeck  1  and again land on the snowdeck  1  after a brief period of being in the air and unsupported by the snowdeck  1 . Such maneuvers may be difficult or impossible if the braking device  6  is activated as soon as the rider&#39;s weight is not supported on the deck  2 . Thus, the braking device  6  may include a delay feature that prevents activation of a braking feature for a period of time after the rider&#39;s weight is no longer supported on the deck  2 . For example, FIG. 16 shows a braking device  6  that incorporates a delay feature. In this illustrative embodiment, the braking device  6  includes a braking element  61  that is rotatably mounted to a housing  63 . The braking element  61  may rotate so that the braking element  61  extends below the bottom surface of the runner  3  to resist movement of the snowdeck  1  on a gliding surface  10 . The braking element  61  is mounted to rotate with a gear  72  that engages one side of a rack  71 . The rack  71  is secured to the deck  2  and moves with the deck  2  as the deck  2  and the runner  3  move toward and away from each other. As a result, when the deck  2  and the runner  3  move toward each other, the rack  71  drives the gear  72  in a counterclockwise direction, thereby lifting the braking element  61  above the bottom surface of the runner  3 . When the deck  2  and the runner  3  move away from each other, e.g., under the force of a spring or other member urging the rack  71  to move upward relative to the housing  63 , the rack  71  drives the gear  72  in a clockwise direction so the braking element  61  rotates to engage the gliding surface  10 . 
     This embodiment also includes a damper or delay element  73  that slows the activation of the braking device  6 . For example, the delay element  73  in this embodiment includes a gear that engages with the rack  71 . The delay element  73  is arranged so that the gear may be freely driven in the clockwise direction, but is damped to resist rotation in the counterclockwise direction. Thus, the delay element  73  may prevent rapid upward travel of the rack  71 , and thus delay activation of the braking element  61 . Dampening of the gear rotation in the delay element  73  may be provided by a friction device, such as a pair of stacked friction disks that are biased together and resist rotation of one disk relative to the other. One of the friction disks may be coupled to the gear in the delay element  73  by a ratchet mechanism that allows the gear to rotate in the clockwise direction without rotation of the coupled disk, but causes the gear and the disk to rotate together when the gear is driven counterclockwise. The delay element  73  may include a device by which a rider can selectively adjust the delay rate for activation of the braking element  61 . For example, experienced riders may adjust the friction or other dampening of the delay element  73  to be relatively high and provide a long delay for brake activation, e.g., increase the contact force between the friction disks. Less experienced riders may adjust the dampening for the delay element  73  to be less and provide a shorter delay for brake activation. 
     It will be understood that the delay function of the delay element  73  may be performed by any suitable mechanism as the described friction disk arrangement is only one illustrative example. Viscous coupling devices, linear dampers, and other devices may be used to slow or otherwise delay movement of the braking element  61 . 
     In the embodiments above that use a separation distance between the deck  2  and the runner  3  to control brake activation, the entire deck  2  may move toward the runner  3  to control braking. However, in other embodiments, only a portion of the deck or another element separate from the deck  2  may be moved relative to the runner  3  to control brake activation. For example, FIG. 17 shows a deck portion  2   a  that may move relative to the deck  2  and the runner  3 . Movement of the deck portion  2   a  may control the activation of a braking device  6 , such as that shown in FIG. 15 or  16 . Thus, in such an embodiment, the spacers  4  need not have a suspension feature to allow the deck  2  to move relative to the runner  3 . In embodiments that use a deck portion  2   a  to control a braking device  6 , a spring or other resilient member may be used to bias the deck portion  2   a  relative to the runner  3 , the braking device  6  or other reference, e.g., so that the deck portion  2   a  is urged to move away from the runner  3 . For example, the embodiment shown in FIG. 16 may include a compression spring that is arranged between the deck portion  2   a  and the housing  63  to bias the deck portion  2   a  away from the housing  63  and the runner  3 . Although the deck portion  2   a  shown in FIG. 17 has an oval shape, the deck portion  2   a  may have any suitable shape and/or size, and may be depressed by a rider&#39;s foot or hand. 
     In another aspect of the invention, an adjustment may be made to control the amount of force needed to deactivate a braking feature. For example, FIG. 18 shows another illustrative embodiment of a braking device  6 . This illustrative embodiment includes a lever-type brake actuation feature similar to that in the embodiment shown in FIG.  15 . That is, downward force on an upturned end of the lever  69  causes the lever  69  to pivot about a hinge  65 , raising the opposite end of the lever  69  and the braking elements  61 . However, in this embodiment, the lever  69  may be adjusted in position along the hinge  65  to allow different levels of downward force on the lever  69  to be required to deactivate the braking element  61 . In addition, the hinge  65  in this embodiment incorporates a delay element that allows the lever  69  to be rotated quickly to lift the braking element  61 , but delays rotation of the lever  69  to lower the braking element  61  below the bottom surface of the runner  3 . As in the embodiment shown in FIG. 16, the delay may be adjusted by turning a thumb wheel or other device, e.g., to adjust a friction or other dampening setting for the delay element  73 . 
     The embodiments shown above generally include mechanical devices that activate or deactivate a braking feature. However, in at least one embodiment, a braking feature may be electronically activated and/or deactivated. For example, FIG. 19 shows a snowdeck  1  having a braking device  6  that is electronically activated or deactivated. In this embodiment, a transmitter  8  that may be worn on the ankle or wrist of a rider transmits a signal that is received by suitable electronic circuitry in the braking device  6 . When the braking device  6  determines that the transmitter  8  is within sufficient range, e.g., within 2-5 feet, the braking device  6  may be deactivated so that movement of the snowdeck  1  along the gliding surface  10  is not resisted. However, when the braking device  6  determines that the transmitter  8  is more than a threshold distance away, e.g., greater than 5 feet, the braking device  6  may be activated to resist movement of the snowdeck  1 . In this embodiment, the braking device  6  may include any of the suitable braking features described above. For example, the braking device  6  may include an arrangement similar to that shown in FIG.  16 . The spring loaded braking element  61  may be retracted manually by the rider, for example, by depressing a deck portion  2   a  or depressing a push button or lever on the braking device  6 . Alternately, the braking device  6  may automatically deactivate the braking element  61 , e.g., by operating a motor to move the braking element  61 . An electronically-controlled latch may prevent movement of the braking element  61  until the transmitter  8  is determined to be out of range. At that time, the latch may be disengaged so that the braking element  61  may rotate and resist movement of the snowdeck  1  on the gliding surface  10 . 
     FIG. 20 is a schematic block diagram of an illustrative embodiment of a braking device  6  that is electronically controlled. In this embodiment, the rack  71  may be depressed, e.g., by a rider pushing down on the rack  71  with a foot or hand, to rotate the gear  72  and attached braking element  61  counterclockwise. A spring (not shown) may resist downward movement of the rack  71  and provide an energy source for activating the braking element  61 . A solenoid-controlled latch  74  or other suitable element may engage with the rack  71 , the gear  72  and/or the braking element  61  when the rack  71  is depressed to lock the braking element  61  in a deactivated position. Operation of the solenoid-controlled latch  74  may be performed by a controller  75  using a power source  76 , e.g., a battery. The controller  75  may include suitable electronic hardware, software and/or firmware to detect signals transmitted from the transmitter  8 , determine the range of the transmitter  8  and control operation of the solenoid latch  74  accordingly. Such detection hardware and software are well known and not described in detail here. For example, the transmitter  8  may constantly, or periodically, output a radio frequency signal that is detectable by the controller  75 . The signal may include a code or other unique identifier so that signals sent from other transmitters or emission sources do not affect the operation of the braking device  6 . The controller  75  may use a proximity detection scheme such that if the power of the signal received from the transmitter  8  falls below a threshold level (e.g., indicating that the transmitter  8  is more than a threshold distance away), the controller  75  may disengage the latch  74  and allow the braking element  61  to rotate clockwise and resist movement of the snowdeck  1  along the gliding surface  10 . 
     It should be understood that the illustrative embodiment of an electronically controlled braking device  6  described above is only one of several possible arrangements. For example, the controller  75  need not detect signals from a remote transmitter  8 , but instead may detect the physical presence of a passive device, such as a magnet stuck to a housing  63  of the braking device  6 . A string or other tether may connect the magnet to the rider so that if the rider is separated from the snowdeck, the magnet is pulled from the housing  63 . The controller  75  may activate the braking device  6  when the presence of the magnet is no longer detected. Such safety-type kill switches are commonly found in exercise and other equipment. The controller  75  may also control the braking device  6  based on detected pressure, e.g., indicating the presence of the rider on the deck  2 , or other detectable conditions that indicate the rider is using the snowdeck  1 . 
     Although particular embodiments are described above in detail, various modifications and improvements will readily occur to those skilled in the art. Such modifications and improvements are intended to be part of this disclosure and within the spirit and scope of the invention. Accordingly, the description of the illustrative embodiments is by way of example only, and the invention is defined, at least in part, by the following claims and their equivalents.