Abstract:
A multi-purpose ski/snowshoe, with a winged frame, an articulated foot plate, and interchangeable bottom surface plugs is described. The multi-purpose ski/snowshoe may be configured in several ways, including a short ski, a short ski with heel-plate brake, and a fully articulated snowshoe. It may be reconfigured by a combination of reversing the winged frame, inverting or interchanging the bottom surface plug, or adjusting the point of articulation. This provides a highly efficient device for foot-powered transportation over a wide variety of winter landscapes.

Description:
CROSS REFERENCE  
       [0001]    This invention claims the benefit of U.S. Provisional Patent Application No. 60/186,153 filed on Feb. 29, 2000. 
     
    
     
       BACKGROUND  
         [0002]    The current invention relates generally to equipment for foot-powered transportation across snow and ice and specifically to a combination ski/snowshoe device that includes a braking system.  
           [0003]    There have been many attempts to provide equipment for snow and ice travel and recreation that is both safe and functional as skis and snowshoes. As a result, there are a large range and variety of skis of different composition, lengths, and shapes, with a multitude of different boots, bindings, and even surface preparations available, providing various degrees of safety and functionality.  
           [0004]    For example, conventional short skis cannot be used in powder, since they have insufficient surface area to allow the skier to “float” on the snow surface. In contrast, on snow, powder, and ice, showshoes have a bottom surface designed to provide appropriate traction.  
           [0005]    It is well recognized that the respective purposes and functions of snowshoes and skis are different. In particular, snowshoes are designed to help a user “grip” the surface being traversed, while skis are designed to allow the user to slide over the surface. Moreover, the shape and length of snowshoes and skis are typically different, with snowshoes being short and wide to support a user&#39;s weight on top of the surface being traversed, while skis are typically narrow and long to allow for speed of traversal across the surface.  
           [0006]    A report in the December 2000 issue of “Skiing” magazine indicates that torn anterior cruciate ligaments (“ACLs”) represent 20 percent of all skiing injuries and that a skier is more likely to completely rip his ACL than he was to break his leg in 1973. It also quotes John Ettlinger, president of Vermont Ski Safety, as stating that designing a ski that performs well when a skier is skiing properly and protects him from himself when he&#39;s skiing in an unsafe manner is nothing more than a simple engineering problem. He goes on to state that such ski designs would perform like any other ski when the skier was well-balanced, but if, for example, the skier started to lean too far back, the ski would progressively lose its carving ability and start to skid a turn, thus breaking the sequence of events leading to ACL sprain and allowing the skier to recover his balance.  
           [0007]    With regard to snowshoes, conventional snowshoes are difficult to maneuver in a transverse direction up or down a steep incline. A conventional snowshoe will force the foot to roll over and sit evenly with or tangent to the surface. If the surface is loose powder, some relief will occur when one side compacts more than the other and the foot is allowed to sit at a more comfortable angle with the body. However, if the snow surface is crusted over with ice or is packed with more dense snow, a conventional snowshoe can be very uncomfortable if a transverse path up or down a steep incline is taken. Many times it is natural to work one&#39;s way up or down a steep incline by walking back and forth and cutting one&#39;s way up or down the incline. This technique reduces the effort of each step and allows one to avoid obstacles by going around them. A conventional snowshoe can force one to go straight up or down a steep incline. This can lead to fatigue and danger if the incline is so steep that is unsafe.  
           [0008]    Therefore, what is needed are new designs for snowshoes and skis that fulfill the functions described above.  
         SUMMARY OF THE INVENTION  
         [0009]    In a first embodiment, a multipurpose braking snowshoe/ski, or “brake ski,” consists of a pair of short, ski-shaped devices that are attached to boots, shoes, or other footwear of the user and have elevated “wings” for providing additional surface area for buoyancy and control. The bottom of the multipurpose snowshoe/ski includes an interchangeable, hinged foot plate, also referred to as a binding plate, that may have a smooth bottom surface for functioning as a ski, or a corrugated bottom surface for functioning as a snowshoe. When the hinged foot plate is configured as a ski, it functions as a brake, enabling the user to lean back, extending and depressing the heel of the plate into the snow, giving additional friction, thus slowing the ski. This action will act to slow the user if even weight is applied to both skis, or to turn the user if more pressure is applied to one ski relative to the other.  
           [0010]    The interchangeable foot plate is attached with a pivot pin that extends through the body of the multipurpose snowshoe/ski, through the foot plate, and into the multipurpose snowshoe/ski body on the other side. There may be several pivot pin positions, allowing the user to set the degree to which the heel of the plate descends into the snow, controlling the amount of friction and braking applied. A top surface of the foot plate is customizable so that an appropriate binding can be attached, allowing the user to select one of the many types of boots and bindings available.  
           [0011]    It will be recognized that the natural position for a skier to go the fastest downhill is to lean forward. When the skier is leaning forward, the multipurpose snowshoe/ski performs like a normal ski and generates no additional drag or braking force. In contrast, the natural reaction for a skier who encounters the need to slow down suddenly is to lean back. This natural reaction will cause the brake to engage. The harder the skier leans back, the stronger the brake force will be.  
           [0012]    The first embodiment addresses three distinct considerations in the field of snowshoe and ski equipment. First, it is a combination snowshoe and ski, allowing the user to easily and quickly change the surface in contact with the snow or ice from “sliding” (ski) to “gripping” (snowshoe). Second, it is of a shape and length appropriate both to ski and snowshoe such that the user can traverse terrain (specifically, narrow downhill and uphill passages) not easily maneuvered by traditional skis or snowshoes. And third, it has an automatic braking system that provides additional safety in preventing anterior cruciate ligament injuries. The embodiment can be easily converted from ski to snowshoe and from snowshoe to ski by simply interchanging the foot plate comprising the bottom surface of the invention. This allows the user the maximum flexibility in choosing his or her route over a variety of uphill and downhill terrain. The process takes only a few moments to remove the current plate and installing the new plate.  
           [0013]    In a second embodiment, a fully articulating snowshoe has a gently tapered or wedged body across its width and away from the center. This allows the snowshoe to easily roll back and forth up to 30 degrees or so, allowing the foot to take on a more natural posture while still engaging a transverse lie on a slope. A crampon plate that attaches to the foot is fully articulating such that the foot has a full range of motion to pitch forward or aft and engage teeth under either the toe or the heel into the surface. Side teeth provide firm engagement so that the snowshoe will not slip on transverse surfaces.  
           [0014]    In a third embodiment, a convertible ski shoe combines all the benefits of the first and second embodiments into a single design. The convertible ski shoe is a versatile device that enables a person to travel at the most efficient rate across a wide range of winter landscape. The convertible ski shoe can be quickly transformed from a fast downhill ski into an all terrain snowshoe in seconds. To do so, a user reaches down and partially pulls out two quick release pins on either side of the ski shoe. A binding plate stays attached to the foot while a convertible plug is flipped over. The foot is then reversed in direction and the ski is transformed into a snowshoe. The quick release pins are pushed back into place to lock the binding plate in the new position. The convertible ski shoe has a ski front end and a snowshoe front end combined into the same body. In snowshoe mode, most of the body length is portioned behind the foot. This insures that the back of the shoe falls and drags against the ground so that the front of the body is lifted up to make it easier to step forward into soft snow. In ski mode, the front of the body extends out further than the back. This configuration is thus optimized for control while skiing.  
           [0015]    In ski mode, the convertible plug can be set to provide some controlled degree of forward rotation before hitting the stop. This can be used for an optional glide mode where the heel is released similar to cross-country skis. The toe is allowed to pivot slightly forward to enable a grabber feature or shovel to dig in slightly and give a cross-country skier a toe hold with which to push off.  
           [0016]    In snowshoe mode, the convertible ski shoe becomes a fully articulating snowshoe and a user can walk or run up or down steep slopes at any angle with comfort, while maintaining maximum control and grip in any slope angle. Moreover, if very tight conditions are encountered, such as climbing among snow-covered rocks, crampons can be released and used as separate devices.  
           [0017]    In a fourth embodiment, a dual bridge convertible ski shoe, also combines all the benefits of the first and second embodiments into a single design. The dual bridge convertible ski shoe is also a versatile device that enables a person to travel at the most efficient rate across a wide range of winter landscape. The dual bridge convertible ski shoe can be quickly transformed from a fast downhill ski into an all terrain snowshoe. To accomplish this, a user reaches down underneath a convertible plug and squeezes together two binding plate release springs to release two bridges. Each bridge has two sets of release springs. One bridge is attached to the forward part of the foot and the other to the aft part of the foot. The binding plate or bridges stay attached to the foot while the convertible plug is flipped over. The foot is then reversed in direction and the ski is transformed into a snowshoe. The dual bridges stay attached to the foot through binding straps or similar devices and fit back into slots on either side of the convertible plug. They snap into place to lock the bridges to the convertible plug.  
           [0018]    The dual bridge convertible ski shoe has a ski front end and a snowshoe front end combined into the same body. In snowshoe mode, most of the body length is portioned behind the foot to insure that the back of the shoe falls and drags against the ground so that the front of the body is lifted up to make it easier to step forward into soft snow. In ski mode, the front of the body extends out further than the back. This configuration provides optimum control while skiing.  
           [0019]    In ski mode, the convertible plug could be set to provide some controlled degree of forward rotation before hitting the stop. This can be used for an optional glide mode where the heel is released similar to cross-country skis. The toe is able to pivot slightly forward to enable a grabber feature or shovel to dig in slightly and give the cross-country skier a toe hold with which to push off.  
           [0020]    In snowshoe mode, the dual bridge convertible ski shoe becomes a fully articulating snowshoe, enabling a user to walk or run up or down steep slopes at any angle with comfort. The user maintains maximum control and grip in any slope angle. Moreover, if very tight conditions are encountered such as climbing among snow covered rocks, the crampons can be released and used as separate devices.  
           [0021]    In a fifth embodiment, a smooth bottom convertible ski shoe combines all the benefits of the first, second, and third embodiments into a single design. The smooth bottom convertible ski shoe is a versatile device that enables a person to travel at the most efficient rate across a wide range of winter landscape. The smooth bottom convertible ski shoe can be quickly transformed from a fast downhill ski into an all terrain snowshoe in seconds. To accomplish this transformation, a user reaches down and releases binding plate locks. A binding plate assembly stays attached to the binding and foot as the foot is lifted up. A convertible plug is attached to the body of the smooth bottom convertible ski shoe by means of two coaxial pivot pin assemblies. The convertible plug assembly is then flipped over or converted. The foot is then reversed in direction and reinserted into the opposite side or snowshoe side of the convertible plug assembly and the ski is transformed into a snowshoe. The binding plate locks are then secured.  
           [0022]    Any number of different kinds of standard bindings can be attached to a deck of the binding plate. The preferred type of binding would a standard snowboard type, such as the K-2 Clicker step in standard or high back system, although any number of Burton binding systems, telemark, cross-country, short ski, such as Solomon Snow Blade or ski shoe, bindings, or crampons such as Atlas Mountain Tracker could also be adapted and mounted. The snowboard bindings would be adapted for use with the foot mounted fore and aft like a standard ski instead of transverse as on a snow board. The more compliant boots used for snow boarding would offer a good balance between flexibility and rigidity for control. The snow board bindings can be adjusted to allow the optimum foot angle for pigeon-toed or bow-legged people to align their ski shoes straight. The cross-country and snowshoe bindings would be more difficult to control because of their lack of foot restraint. The short ski bindings are designed for use with regular ski boots, which are very rigid for comfortable walking. Other types of bindings, including various strap arrangements can be mounted a number of ways through strap binding holes not detailed.  
           [0023]    A technical advantage achieved with the first embodiment is that, while conventional skis are difficult to maneuver down steep narrow trails., the multipurpose snowshoe/ski, when in the ski configuration, is a short ski, appropriate to these types of terrain.  
           [0024]    Another technical advantage achieved with the first embodiment is that, while conventional skis are difficult to maneuver up steep narrow trails, the multipurpose snowshoe/ski can be easily converted to a snowshoe to be used in these circumstances.  
           [0025]    Yet another technical advantage achieved with the first embodiment is that it takes advantage of the natural inclination of a skier to lean back when he wants to slow down by causing such an action to trigger the braking mechanism of the embodiment, slowing the skier and allowing him to regain his balance.  
           [0026]    Yet another technical advantage achieved with the first embodiment is that it provides a more versatile skiing platform to improve the safety, flexibility, performance, and cost over conventional ski art.  
           [0027]    A technical advantage achieved with the second embodiment is that, while conventional snowshoes allow the toe to rotate forward and dig in for forward traction, but the heel motion is restricted, the fully articulating snowshoe allows the foot go where it wants to naturally go, independent of the surface orientation.  
           [0028]    Another technical advantage of the second embodiment is that it provides more flexibility to traverse a variety of surfaces in a wide range of conditions and provides more comfort to the user with less fatigue and chance of injury.  
           [0029]    Yet another technical advantage of the second embodiment is that the crampon foot piece is also removable so that the user can go places where a snowshoe body would get in the way without a lot of extra equipment for traction.  
           [0030]    A technical advantage achieved with the third embodiment is that it enables skiing in light powder because the body has enough lift surface area to keep a skier floating up.  
           [0031]    A further technical advantage achieved with the third embodiment is that it is small, light, inexpensive and compact and facilitates skiing with speed and confidence while improving safety, even when skiing down tight narrow trails or glade runs between trees, because the brake can be used for control and steering without cutting.  
           [0032]    Yet another technical advantage achieved with the third embodiment is that it is easier to learn because of the easy instant and automatic reflex control and braking design.  
           [0033]    A technical advantage of the fourth embodiment is that it enables skiing in light powder because the body has enough lift surface area to keep a skier buoyed up.  
           [0034]    Another technical advantage of the fourth embodiment is that it is small, light, and inexpensive and facilitates skiing with speed and confidence while improving safety when skiing down tight narrow trails or glade runs between trees, because the brake can be used for control and steering without cutting.  
           [0035]    Yet another technical advantage of the fourth embodiment is that it is easier to learn because of the easy instant and automatic reflex control and braking design.  
           [0036]    A technical advantage achieved with the fifth embodiment is that the smooth bottom convertible ski shoe is quickly transformed from a fast down hill ski into an all terrain snowshoe in seconds.  
           [0037]    Another technical advantage achieved with the fifth embodiment is that any number of different types of bindings and boots can be used therewith. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0038]    [0038]FIG. 1 is a top perspective view of the first embodiment.  
         [0039]    [0039]FIG. 1A is another top perspective of the first embodiment.  
         [0040]    [0040]FIG. 2 is a bottom perspective view of the first embodiment.  
         [0041]    [0041]FIG. 2A is another bottom perspective view of the first embodiment.  
         [0042]    [0042]FIG. 3 is a top perspective view of the first embodiment with the brake removed.  
         [0043]    [0043]FIG. 3A is another top perspective view of the first embodiment with the brake removed.  
         [0044]    [0044]FIG. 4 is a bottom perspective view of the first embodiment with the brake removed.  
         [0045]    [0045]FIG. 4A is another bottom perspective view of the first embodiment with the brake removed.  
         [0046]    [0046]FIG. 5 is a top perspective view of a brake ski cover of the first embodiment.  
         [0047]    [0047]FIG. 6 is a bottom perspective view of a binding attachment plate, or brake, of the first embodiment.  
         [0048]    [0048]FIG. 7 is a side perspective view of the binding attachment plate of FIG. 6.  
         [0049]    [0049]FIG. 8 is another perspective view of the binding attachment plate of FIG. 6.  
         [0050]    [0050]FIG. 9 is yet another perspective view of the binding attachment plate of FIG. 6.  
         [0051]    [0051]FIG. 10A is a top plan view of the first embodiment.  
         [0052]    [0052]FIG. 10B is a side plan view of the first embodiment.  
         [0053]    [0053]FIG. 10C is a bottom plan view of the first embodiment.  
         [0054]    [0054]FIG. 11A is a sectional view of the first embodiment as illustrated in FIG. 10A along the line A-A.  
         [0055]    [0055]FIG. 11B is a sectional view of the first embodiment as illustrated in FIG. 10B along the line B-B.  
         [0056]    [0056]FIG. 11C is a front plan view of the first embodiment.  
         [0057]    [0057]FIG. 11D is a rear plan view of the first embodiment.  
         [0058]    [0058]FIG. 12 is a top perspective view of the second embodiment.  
         [0059]    [0059]FIG. 13 is a bottom perspective view of the second embodiment.  
         [0060]    [0060]FIG. 13A is another bottom perspective view of the second embodiment.  
         [0061]    [0061]FIG. 14 is a top perspective view of the second embodiment with the crampon removed.  
         [0062]    [0062]FIG. 15 is a bottom perspective view of the second embodiment with the crampon removed.  
         [0063]    [0063]FIG. 16 is a top perspective view of a crampon plate of the second embodiment.  
         [0064]    [0064]FIG. 17 is a bottom perspective view of the crampon plate of the second embodiment.  
         [0065]    [0065]FIG. 18A is a top plan view of the second embodiment.  
         [0066]    [0066]FIG. 18B is a side plan view of the second embodiment.  
         [0067]    [0067]FIG. 18C is a rear plan view of the second embodiment.  
         [0068]    [0068]FIG. 18D is a front plan view of the second embodiment.  
         [0069]    [0069]FIG. 19A is a sectional view of the second embodiment as illustrated in FIG. 18A along the line A-A.  
         [0070]    [0070]FIG. 19B is a sectional view of the second embodiment as illustrated in FIG. 18B along the line B-B.  
         [0071]    [0071]FIG. 19C is a front plan view of the second embodiment.  
         [0072]    [0072]FIG. 19D is a rear plan view of the second embodiment.  
         [0073]    [0073]FIG. 20 is a top perspective view of the third embodiment configured as a ski.  
         [0074]    [0074]FIG. 21 is a bottom perspective view of the third embodiment configured as a ski.  
         [0075]    [0075]FIG. 21A is another bottom perspective view of the third embodiment configured as a ski.  
         [0076]    [0076]FIG. 22 is a top perspective view of the third embodiment configured as a showshoe.  
         [0077]    [0077]FIG. 23 is a bottom perspective view of the third embodiment configured as a snowshoe illustrating a convertible plug.  
         [0078]    [0078]FIG. 23A is another bottom perspective view of the third embodiment configured as a snowshoe illustrating a convertible plug.  
         [0079]    [0079]FIG. 24 is a top perspective view of the third embodiment with the convertible plug removed.  
         [0080]    [0080]FIG. 25 is a bottom perspective view of the third embodiment with the plug removed.  
         [0081]    [0081]FIG. 26 is a top perspective of a binding attachment plate of the third embodiment including the convertible plug.  
         [0082]    [0082]FIG. 27 is a bottom perspective view of the binding attachment plate of the third embodiment.  
         [0083]    [0083]FIG. 28 is a bottom perspective view of a portion of the convertible plug shown in FIG. 26.  
         [0084]    [0084]FIG. 29 is another bottom perspective view of a portion of the convertible plug shown in FIG. 26.  
         [0085]    [0085]FIG. 30 illustrates a pivot pin of the third embodiment.  
         [0086]    [0086]FIG. 31A is a top plan view of the third embodiment.  
         [0087]    [0087]FIG. 31B is a side plan view of the third embodiment.  
         [0088]    [0088]FIG. 31C is a rear plan view of the third embodiment.  
         [0089]    [0089]FIG. 31D is a front plan view of the third embodiment.  
         [0090]    [0090]FIG. 31E is a bottom plan view of the third embodiment.  
         [0091]    [0091]FIG. 32A is a sectional view of the third embodiment as illustrated in FIG. 31A along the line A-A.  
         [0092]    [0092]FIG. 32B is a sectional view of the third embodiment as illustrated in FIG. 31B along the line B-B.  
         [0093]    [0093]FIG. 32C is a front plan view of the third embodiment.  
         [0094]    [0094]FIG. 32D is a rear plan view of the third embodiment.  
         [0095]    [0095]FIG. 33 is a top perspective view of the fourth embodiment configured as a ski.  
         [0096]    [0096]FIG. 34 is a bottom perspective view of the fourth embodiment configured as a ski.  
         [0097]    [0097]FIG. 34A is another bottom perspective view of the fourth embodiment configured as a ski.  
         [0098]    [0098]FIG. 35 is top perspective view of the fourth embodiment configured as a showshoe.  
         [0099]    [0099]FIG. 36 is a bottom perspective view of the fourth embodiment configured as a showshoe illustrating a plug and bridge thereof.  
         [0100]    [0100]FIG. 36A is another bottom perspective view of the fourth embodiment configured as a showshoe illustrating a plug and bridge thereof.  
         [0101]    [0101]FIG. 37 is a top perspective view of the fourth embodiment with the plug and bridge removed.  
         [0102]    [0102]FIG. 37A is another top perspective view of the fourth embodiment with the plug and bridge removed.  
         [0103]    [0103]FIG. 38 is a bottom perspective view of the fourth embodiment with the plug and bridge removed.  
         [0104]    [0104]FIG. 38A is another bottom perspective view of the fourth embodiment with the plug and bridge removed.  
         [0105]    [0105]FIG. 38B is yet another bottom perspective view of the fourth embodiment with the plug and bridge removed.  
         [0106]    [0106]FIG. 39 is a top perspective view of a binding attachment plate, or bridge, section of the fourth embodiment.  
         [0107]    [0107]FIG. 39A is another top perspective view of a binding attachment plate, or bridge, section of the fourth embodiment.  
         [0108]    [0108]FIG. 40 is a bottom perspective view of a binding attachment plate, or bridge, section of the fourth embodiment.  
         [0109]    [0109]FIG. 40A is another bottom perspective view of a binding attachment plate, or bridge, section of the fourth embodiment.  
         [0110]    [0110]FIG. 41 is a top perspective view of a convertible plug section of the fourth embodiment.  
         [0111]    [0111]FIG. 41A is another top perspective view of a convertible plug section of the fourth embodiment.  
         [0112]    [0112]FIG. 42 is bottom perspective view of a convertible plug section of the fourth embodiment.  
         [0113]    [0113]FIG. 42A is another bottom perspective view of a convertible plug section of the fourth embodiment.  
         [0114]    [0114]FIG. 43 illustrates a pivot pin of the fourth embodiment.  
         [0115]    [0115]FIG. 43A is another illustration of the pivot pin of the fourth embodiment.  
         [0116]    [0116]FIG. 44A is a top plan view of the fourth embodiment.  
         [0117]    [0117]FIG. 44B is a side plan view of the fourth embodiment.  
         [0118]    [0118]FIG. 44C is a bottom plan view of the fourth embodiment.  
         [0119]    [0119]FIG. 45A is a sectional view of the fourth embodiment as illustrated in FIG. 44B along the line A-A.  
         [0120]    [0120]FIG. 45B is a sectional view of the fourth embodiment as illustrated in FIG. 44A along the line B-B.  
         [0121]    [0121]FIG. 45C is a front plan view of the fourth embodiment.  
         [0122]    [0122]FIG. 45D is a rear plan view of the fourth embodiment.  
         [0123]    [0123]FIG. 46 is a top perspective view of the fifth embodiment configured as a ski.  
         [0124]    [0124]FIG. 46A is another top perspective view of the fifth embodiment configured as a ski.  
         [0125]    [0125]FIG. 47 is a bottom perspective view of the fifth embodiment configured as a ski.  
         [0126]    [0126]FIG. 47A is another bottom perspective view of the fifth embodiment configured as a ski.  
         [0127]    [0127]FIG. 48 is a side perspective view of the fifth embodiment configured as a ski.  
         [0128]    [0128]FIG. 49 is an exploded view of the fifth embodiment configured as a ski.  
         [0129]    [0129]FIG. 49A is another exploded view of the fifth embodiment configured as a ski.  
         [0130]    [0130]FIG. 49B is another exploded view of the fifth embodiment configured as a ski.  
         [0131]    [0131]FIG. 50A is a top plan view of the fifth embodiment configured as a ski.  
         [0132]    [0132]FIG. 50B is a side plan view of the fifth embodiment configured as a ski.  
         [0133]    [0133]FIG. 50C is a bottom plan view of the fifth embodiment configured as a ski.  
         [0134]    [0134]FIG. 50D is a front plan view of the fifth embodiment configured as a ski.  
         [0135]    [0135]FIG. 50E is a rear plan view of the fifth embodiment configured as a ski.  
         [0136]    [0136]FIG. 51 is a sectional view of the fifth embodiment as illustrated in FIG. 50A along the line A-A.  
         [0137]    [0137]FIG. 52 is a top perspective view of the fifth embodiment configured as a showshoe.  
         [0138]    [0138]FIG. 53 is a bottom perspective view of the fifth embodiment configured as a snowshoe.  
         [0139]    [0139]FIG. 53A is another bottom perspective view of the fifth embodiment configured as a snowshoe.  
         [0140]    [0140]FIG. 54A is a side perspective view of the fifth embodiment configured as a snowshoe illustrating no rotation of a convertible plug thereof.  
         [0141]    [0141]FIG. 54B is a side perspective view of the fifth embodiment configured as a snowshoe illustrating maximum rotation of a convertible plug thereof.  
         [0142]    [0142]FIGS. 55A and 55B respectively illustrate side perspective views of the fifth embodiment configured as a snowshoe in climbing mode and descending mode.  
         [0143]    [0143]FIG. 56 is a top perspective view of the fifth embodiment configured as a snowshoe illustrating a maximum heel down mode.  
         [0144]    [0144]FIG. 57 is a top perspective view of the fifth embodiment in glide mode illustrating no rotation of the convertible plug thereof.  
         [0145]    [0145]FIGS. 58A and 58B respectively illustrate side perspective views of the fifth embodiment in glide mode illustrating zero and maximum rotation of the convertible plug.  
         [0146]    [0146]FIG. 59 is a top perspective view of a body portion of the fifth embodiment.  
         [0147]    [0147]FIG. 59A is another top perspective view of a body portion of the fifth embodiment.  
         [0148]    [0148]FIG. 60 is a bottom perspective view of the body portion of the fifth embodiment.  
         [0149]    [0149]FIG. 61A is a top plan view of a body assembly of the fifth embodiment.  
         [0150]    [0150]FIG. 61B is a side plan view of the body assembly of the fifth embodiment.  
         [0151]    [0151]FIG. 61C is a bottom plan view of the body assembly of the fifth embodiment.  
         [0152]    [0152]FIG. 61D is a front plan view of the body assembly of the fifth embodiment.  
         [0153]    [0153]FIG. 61E is a rear plan view of the body assembly of the fifth embodiment.  
         [0154]    [0154]FIG. 62A is a sectional view of the body assembly of the fifth embodiment as illustrated in FIG. 61A along the line B-B.  
         [0155]    [0155]FIG. 62B is a sectional view of the body assembly of the fifth embodiment as illustrated in FIG. 61B along the line A-A.  
         [0156]    FIGS.  63 A- 63 C are various sectional views of the body assembly of the fifth embodiment as illustrated in FIG. 61A along lines C-C, D-D, and E-E, respectively.  
         [0157]    [0157]FIG. 64 illustrates various sectional views of the body assembly of the fifth embodiment as illustrated in FIG. 61B along lines F-F, G-G, H-H, J-J, K-K, L-L, and M-M.  
         [0158]    [0158]FIG. 65 illustrates a plug rotation limiter clip of the fifth embodiment.  
         [0159]    [0159]FIG. 66 is a top perspective view of a binding attachment plate assembly of the fifth embodiment.  
         [0160]    [0160]FIG. 67 is a bottom perspective view of the binding attachment plate assembly of the fifth embodiment.  
         [0161]    [0161]FIG. 68 is an exploded view of the binding attachment plate assembly of the fifth embodiment.  
         [0162]    FIGS.  69 A- 69 F respectively illustrate top, side, bottom, left, and right end plan views of a convertible plug assembly of the fifth embodiment.  
         [0163]    FIGS.  70 A- 70 E respectively illustrate sectional views of the convertible plug assembly of the fifth embodiment as shown in FIG. 69A along the lines A-A, B-B, C-C, D-D, and E-E.  
         [0164]    FIGS.  71 A- 71 C respectively illustrate sectional views of the convertible plug assembly of the fifth embodiment as shown in FIG. 69B along the lines O-O, F-F, and L-L.  
         [0165]    [0165]FIG. 72 illustrates various detailed views of a lock plug of the fifth embodiment.  
         [0166]    [0166]FIG. 73 illustrates various detailed views of a pivot pin doubler of the fifth embodiment.  
         [0167]    [0167]FIGS. 74 and 75 are top perspective views of a convertible plug assembly of the fifth embodiment.  
         [0168]    [0168]FIG. 76 is a bottom perspective view of the convertible plug assembly of the fifth embodiment.  
         [0169]    [0169]FIG. 77 illustrates various views of a pivot pin assembly of the fifth embodiment.  
         [0170]    [0170]FIG. 78 is an isometric view of the pivot pin assembly of the fifth embodiment.  
         [0171]    [0171]FIG. 79 illustrate various views of a plug rotation limiter pin of the fifth embodiment.  
         [0172]    FIGS.  80 A- 80 E illustrate various views of a convertible plug of the fifth embodiment.  
         [0173]    FIGS.  81 A- 81 B illustrate various views of a convertible plug of the fifth embodiment. 
     
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS  
       [0174]    The present invention can be described with several examples given below. It is understood, however, that the examples below are not necessarily limitations to the present invention, but are used to describe typical embodiments of operation.  
         [0175]    First Embodiment—Brake Ski  
         [0176]    [0176]FIG. 1 is a top perspective view of a brake ski  10  of the first embodiment of the present invention, which is adapted for wearing on either the right foot or left foot. It is to be understood that brake ski  10  is but one of a pair of the brake skis of the first embodiment, the other of that same pair being an appropriate mirror image of the brake ski  10 .  
         [0177]    Referring now to FIGS. 1, 1A,  2 ,  2 A,  3 , and  3 A, it can be seen that the brake ski  10  includes a body  11  that, while unitary in construction, may be thought of as being comprised of five portions, including a center portion  11   a , a forward portion  11   b , an aft portion  11   c , a nose portion  11   d , and a tail portion  11   e . As best seen in FIG. 3, the center portion  11   a  extends along the cutout region. Outer beams  12  are contained in the narrow center portion  11   a  around a brake aperture  14 . The outer beams  12  are proportioned to transition bending, shear, and twist loads from the forward portion  11   b , a constant section forward of the brake aperture, to the aft portion  11   c , a constant section aft of the brake aperture. As best shown in FIG. 3, the nose portion  11   d  forms the transition to a forwardmost point  16 , and is curved upward similar to existing ski designs. The nose portion  11   d  insures that the body  11  stays on top of the snow surface and rides smoothly over small obstacles or choppy ice and snow. The tail portion  11   e , forms the transition to a rearwardmost point  18 . Although the tail portion  11   e , as shown in FIG. 3, is very similar to the nose portion  11   e , it could be truncated without an upward arch. The shape of the various portions can be changed and styled in various ways without changing or sacrificing the basic function of the brake ski  10 .  
         [0178]    As shown in FIGS. 3, 4, and  4 A, a primary snow contact surface  20  of the brake ski body  11  makes contact with a surface over which a wearer is traversing. In soft snow or powder, a secondary snow contact surface, or “wings,”  24  will also make contact with the snow surface. The overall brake ski body  11  can be proportioned/sized to have sufficient area to keep skiers of various weights floating up in soft snow or deep powder. The combination of primary  20  and secondary snow contact surfaces  24  will allow a short ski design, as depicted in FIG. 1, to act similarly to a long ski. Current narrow short ski designs are not functional in deep powder conditions because of a lack of sufficient lift.  
         [0179]    Referring now to FIGS.  6 - 9 ,  10 A- 10 C, and  11 A- 11 D, as best illustrated in FIGS.  11 A- 11 D, the brake ski body  11  is connected to the binding attachment plate or brake  26  with a pivot pin  28 . Rolling motion is imparted by the foot through the pivot pin  28  and into the brake ski body  11 . This rolling motion causes either of two inner edges  30  (FIG. 4) to dig into the snow for directional control similar to existing short or long ski designs. A roll angle is sufficient to allow this rolling motion to occur without interference from the wings  24 . In case of extreme rolling due to a fall or extreme slopes, an outside edge  34  can cause the inner edge  30  to lift off the snow surface. The inner edges  30  are simply sharp corners of the parent material of the brake ski body  11 . Molded in metal inserts could be used to improve the cutting action of the edges if more control is desired especially on ice. However, if extreme roll conditions are experienced and the outside edges cause the inner edges to pry off of the surface, a loss of control could result. If the two edges are similar in construction and geometry, then they will both perform similarly, and a surprise loss of control will not be experienced. Therefore, it is recommended that both inner  30  and outer edges  34  have inserts or have similar geometry and material. The outer edges  34  as depicted are not optimum and have a large gentle radius and an edge that is not straight and parallel to the inner edges  30 .  
         [0180]    The brake ski body  11  can be constructed a number of ways, the preferred one being a two piece hollow design comprising an upper and lower shell preferably constructed from a reinforced injection molded plastic. Injection molded parts minimize the touch labor required to set up each part. The reinforcement is preferably a longer fiber variety for maximum strength, stiffness, and damage tolerance at minimal weight. The two halves preferably have a snap fit design where plastic snap elements permanently lock the two halves together. Once the two halves lock together, they act as an integral closed cell box. Using shear bosses would insure that the two halves would act as a single torque box. This manufacturing method would also be consistent with the other parts. Local stiffeners and internal ribs may be used to internally stiffen the skins of the shells. Local areas of higher stress could be strengthened by an increase in thickness. An alternate method to assemble the halves would be to secure them together with fasteners or screws spaced periodically around the perimeter.  
         [0181]    The body  11  could also alternately be constructed as described above, except the snap feature(s) could be replaced with a bond or welding. The body  11  could also alternately be constructed as a one piece foam filled or hollow part having a skin material, such as epoxy-bonded fiberglass, carbon or a metallic material, such as aluminum, disposed thereover. The skin material could form a bonded assembly with an internal foam core and could be a wet lay up over a foam core to save weight. An alternate means of manufacture would involve some form of resin transfer molding or vacuum assist resin transfer molding of resin into a closed cavity mold with dry preform broad goods over an internal mandrel. A hollow design could also be produced using a rotomolding process.  
         [0182]    As best shown in FIGS. 3 and 6, a toe surface  37  of the brake ski body  11  is shaped to interfere and contact with a corresponding toe surface  38  on the brake  26 . This contact will prevent a toe portion  26   b  of the brake  26  from digging into the snow surface as the skier leans forward and will prevent a sudden deceleration or loss of control. As shown in FIGS. 4 and 9, a heel surface  40  of the brake ski body  11  is designed not to interfere with a corresponding heel surface  42  of the brake  26 . If the heel surfaces  40  and  42  are radiused with the center at a pivot axis, a tight fit will insure that the gap is minimized and foreign objects can not easily get wedged or trapped.  
         [0183]    As shown in FIGS. 3, 8, and  11 A- 11 D, the brake  26  is attached to the brake ski body  11  by means of a pivot pin  28 . The pivot pin  28  is mounted along a transverse “Y” axis through pivot holes  46  in each of the two outer beams  12  of the brake ski body  11  and corresponding pivot holes  48  contained in the brake  26 . A pin height is set to keep the pivot pin  28  clear of the rolling clearance and up into the wings  24  without any additional lugs or other features. The pivot pin  28  is shown as comprising a single piece with a head formed at installation on the shank. The type and details for the pivot pin could vary considerably. The pivot pin  28  could be fixed as shown or removable. The brake  26  is free to rotate about the pivot axis  44 . Although the pivot axis is illustrated as being roughly at the middle of the brake  26 , the axis could be shifted either forward or aft to make the braking action stronger or weaker.  
         [0184]    Referring now to FIGS.  6 - 8 , it can be seen that the binding attachment plate or brake  26 , while unitary in construction, may be thought of as being comprised of three portions, including, a center portion  26   a , the toe portion  26   b , and a heel portion  26   c . As best shown in FIG. 9, the center portion  26   a  extends along the constant section region. The toe portion extends the tangency to a toe surface  56 , and the heel portion  26   b  extends from the opposite tangency to the heel surface  58 . In operation, when a skier wants to slow down or stop, weight is simply shifted to the heel portion  26   b  of the brake. The heel portion  26   b  then will push down into the surface of the snow and cause the snow to displace downward and to the side. The energy required to displace the snow will cause the skier to slow down and finally stop.  
         [0185]    As shown in FIGS.  6 - 9 , the brake  26  also has a primary snow contact surface  60  that makes contact with the surface over which the wearer is traversing. In soft snow or powder, a secondary snow contact surface, or “wings,”  62  will also make contact with the snow surface as described for the brake ski body  11  above. When a skier wants to ski without braking action or restraint, weight is shifted forward, and the brake  26  rotates into a position in which the primary and secondary snow contact surfaces  60 ,  62  of the brake align themselves with the primary and secondary surfaces snow contact surfaces  20 ,  24 , of the body  11 . In this position, the brake ski  10  offers very little resistance to sliding. The width of the brake  26  depicted here as narrower than the foot. There is no need to make the brake  26  wider than the foot since only a small engagement of the heel portion  26   c  will allow sufficient braking force. This should reduce the overall size and width of the brake ski  10 .  
         [0186]    Referring to FIG. 8, the brake  26  can be constructed a number of ways, the preferred one being a one piece injection molding made from a reinforced plastic, as injection molded parts minimize the touch labor required to set up each part. The reinforcement material could be a longer fiber variety for maximum strength, stiffness, and damage tolerance at minimal weight. Local stiffeners and ribs  64  would be used to stiffen the skins of an outer shell  66 . The ribs  64  form a crisscrossed diagonal pattern to maximize the torsional stiffness along the longitudinal “X” axis of the brake. Binding attach bosses  68  are located to provide a built up area in which to mount a standard ski binding, a cross-country or telemarking binding. These bindings would be attached with fasteners at binding attachment holes  70  disposed through an outer flange  71 .  
         [0187]    To prevent moisture from accumulating in the cavities of the brake  26  and adding unnecessary weight to the device, an optional cover  72 , as illustrated in FIGS. 5, 11A, and  11 B, can be sandwiched between the binding and the brake to seal off the inner cavities of the brake. The cover  72  has an edge  72   a  that matches the brake  26  and holes  72   b  that corresponded to the binding attach holes  70 . Alternately, a stiff closed foam insert material (not shown) could be molded or cut to fit snugly into the open cavities between the ribs and the shell of the brake to provide a light weight inexpensive seal. The foam insert could be glued in place to keep it secure.  
         [0188]    In an alternate brake ski arrangement, the brake  26  spans a traditionally-shaped center ski portion. The brake surface is divided up into two surfaces on each side of the center ski portion and there is a bridge like structure that spans the center ski portion and joins together the two brake surfaces. A pivot pin connects the center portion to the brake to allow it to rotate backwards for braking. A stop prevents excessive forward rotation. The binding is attached to the bridge portion of the brake  
         [0189]    Second Embodiment—Fully Articulating Snowshoe  
         [0190]    [0190]FIG. 12 is a top perspective view of a fully articulating snowshoe  200  of the second embodiment of the present invention, which is adapted for wearing on either the right foot or left foot. It is to be understood that the fully articulating snowshoe  200  is but one of a pair of the fully articulating snowshoes of the second embodiment, the other of that same pair being an appropriate mirror image of fully articulating snowshoe  200 .  
         [0191]    Referring now to FIGS. 13, 13A,  14 , and  15 , as best shown in FIG. 14, it can be seen that a body  202  of the fully articulating snowshoe  200 , while unitary in construction, may be thought of as being comprised of five portions, including, a center portion  202   a , a forward portion  202   b , an aft portion  202   c , a nose portion  202   d , and a tail portion  202   e . The center portion  202   a  extends along a cutout region. Outer beams  204  are contained in the narrow center portion  202   a  around a crampon aperture  206 . The outer beams  204  are proportioned to transition the bending, shear and twist loads from the forward portion  202   b  that extends along the essentially constant region as shown in FIG. 15, to the aft portion  202   c , that extends along the essentially constant region also shown in FIG. 15. The nose portion  202   d , which that forms the transition to a forwardmost snowshoe point  208 , is curved upward as best-shown in FIG. 14 and is styled with an optional bear claw arch  210  pattern. The tail portion  202   e , which transitions as shown in FIG. 14 to a rearwardmost point  212 , is curved upward. The shape of the various portions can be changed and styled in various ways without changing or sacrificing the basic function of the fully articulating snowshoe  200 .  
         [0192]    As shown in FIG. 15, a primary snow contact surface  214  of the body  202  makes contact with a surface over which the wearer is traversing. In soft snow or powder, a secondary snow contact surface or “wings”  218  will also make contact with the traversal surface. The overall body  202  can be proportioned to have sufficient area to prevent sinking in snowshoe mode. Since the secondary snow contact surface  218  is offset from the primary snow contact surface  214 , both surfaces can be nearly flat and parallel with respect to the ground plane while allowing the fully articulating snowshoe to freely roll form side to side. In snowshoe mode, the primary snow contact surface  214  will sink into soft snow first. The secondary snow contact surface  218  will provide enough extra support to keep the user from sinking. The secondary snow contact surface  218  is almost parallel with the ground and will not tend to wedge into the snow as a result.  
         [0193]    Referring now to FIGS. 16, 17,  18 A- 18 D, and  19 A- 19 C, the body  202  is connected to a binding attachment plate, or “crampon plate,”  224  with a pivot pin  226 . Rolling motion is imparted by the foot through the pivot pin  226  and into the body  202 . A roll angle is sufficient to allow this rolling motion to occur without interference from the wings  218 .  
         [0194]    The body  202  can be constructed a number of ways, the preferred one being a two piece hollow design comprising an upper and lower shell preferably constructed from a reinforced injection molded plastic. Injection molded parts minimize the touch labor required to set up each part. The reinforcement is preferably a longer fiber variety for maximum strength, stiffness, and damage tolerance at minimal weight. The two halves preferably have a snap fit design where plastic snap elements permanently lock the two halves together. Once the two halves lock together, they act as an integral closed cell box. Using shear bosses would insure that the two halves would act as a single torque box. This manufacturing method would also be consistent with the other parts. Local stiffeners and internal ribs may be used to internally stiffen the skins of the shells. Local areas of higher stress could be strengthened by an increase in thickness. An alternate method to assemble the halves would be to secure them together with fasteners or screws spaced periodically around the perimeter.  
         [0195]    The body  202  could also alternately be constructed as described above, except the snap feature(s) could be replaced with a bond or welding. The body  202  could also alternately be constructed as a one piece foam filled or hollow part having a skin material, such as epoxy-bonded fiberglass, carbon or a metallic material, such as aluminum, disposed thereover. The skin material could form a bonded assembly with an internal foam core and could be a wet lay up over a foam core to save weight. An alternate means of manufacture would involve some form of resin transfer molding or vacuum assist resin transfer molding of resin into a closed cavity mold with dry preform broad goods over an internal mandrel. A hollow design could also be produced using a rotomolding process.  
         [0196]    As best shown in FIGS. 14, 16, and  17 , a toe surface  230  and a heel surface  232  of the fully articulating snowshoe body  202  are shaped so as not to interfere and contact with corresponding end surfaces  234  on the crampon plate  224 . This will ensure unrestrained fully articulating toe and heel engagement in snowshoe mode. The toe surface  230  and the heel surface  232  of the body  202  and the corresponding end surfaces  234  of a convertible plug are radiused with the center at a pivot axis, a tight fit will insure that the gap is minimized and foreign objects can not easily get wedged or trapped.  
         [0197]    As best shown in FIGS.  18 A- 18 D and  19 A- 19 C, the crampon plate  224  is attached to the body  202  by means of one pivot pin  226 . As shown in FIG. 17, the pivot pin  226  is protected from damage by capturing it internally inside a pivot hole rib  240 . The pivot hole  242  is located inside the pivot hole rib  240  that has been widened to accept it. The crampon plate  224  is free to rotate about the pivot axis. The pin height is set to keep the pivot pin  226  clear of the ground plane when the body  202  is rolled to either side for walking transverse along inclines in snowshoe mode. As best shown in FIGS.  15 - 17 , the pivot pin  226  is mounted along a transverse “Y” axis through pivot holes  246  in each of the two outer beams  204  of the body  202  and corresponding pivot holes  242  in the crampon plate  224 . The pivot pin  226  engages through lugs  250  that hang down from the outer beams  204  of the body  202 .  
         [0198]    The pivot pin  226  is detailed as a quick release pin, although many other types of shear pins would work in this application. A simple pivot pin similar to the one shown for the brake ski  10  would work. Or a simple spring clip (not shown) could be slipped through a small hole transverse to the longitudinal axis of the pivot pin or a self locking wing nut could be used to make a simple releasable pin. The pivot axis is located roughly at the middle of the convertible plug. A single removable pivot pin could be placed in any number of multiple pivot hole positions (not shown), located forward and aft of each other along the longitudinal axis of the ski shoe, to customize the braking or gripping response. This optional design where there are multiple positions for a single removable pivot pin that passes through the entire convertible plug would be the best arrangement for an initial prototype to investigate overall performance of snowshoe geometric relationships.  
         [0199]    The configuration of the pivot pin  226  is the same as that described with reference to FIG. 43A below.  
         [0200]    Referring now to FIGS. 16, 17, and  13 A, it can be seen that the crampon plate  224 , while unitary in construction, may be thought of as comprising three portions, including a center portion  224   a , a toe portion  224   b , and a heel portion  224   c . As best seen in FIG. 14, the center portion  224   a  extends along the region of constant width. The toe and heel portions  224   b  and  224   c  extend along the end transition radius to an end surface  234 . In snowshoe mode, weight is simply shifted to either the toe portion  224   b  or heel portion  224   c  to cause the convertible plug to rotate and engage teeth  268  for gripping and traction. The width of the crampon plate  224  is wider than the foot to allow a full range of motion of the foot.  
         [0201]    The crampon plate  224  can be constructed a number of ways, the preferred one being a one piece injection molding made from a reinforced plastic, as injection molded parts minimize the touch labor required to set up each part. The reinforcement material could be a longer fiber variety for maximum strength, stiffness, and damage tolerance at minimal weight. As shown in FIGS. 16 and 17, longitudinal ribs  270  and lateral ribs  272  can be used to stiffen skins of a deck  274 . Optional binding attach bosses and binding attach holes are not shown, but could be detailed in the deck  274  to receive standard snowboard style bindings. The snowboard style bindings are highly recommended because of their excellent support of the foot and ankle. Other types of bindings, including various strap arrangements can be mounted a number of ways through either forward strap binding holes (not shown). The deck  274  and outer flange  264  of the binding attachment plate  224  can support any number and arrangements of strap holes or additional flanges or other features that would be molded into or would extend above the surface of the deck  274 . Various other types of telemark, cross-country, snowshoe, or Rottefella bindings can be mounted to standard mounting holes and inserts located on the surface of the deck  274 . An optional non-skid surface  278  feature is shown on the deck surface to keep the foot from sliding around.  
         [0202]    The binding attachment plate  224  has an outer flange  264  with teeth  269  formed on the edge. These teeth  268  provide traction and gripping. Although the teeth  268  are best shown in FIG. 17 as integral with the rest of the convertible plug material, an optional metal or other material insert could be used in an injected molded part to make the teeth edges more durable and effective. For cost considerations, however, the integral material approach has merit.  
         [0203]    To prevent snow and ice from accumulating in the cavities of the underside of the binding attachment plate  224  and adding unnecessary weight to the device, an optional stiff closed foam insert material (not shown) could be molded or cut to fit snugly into the open cavities between the ribs and the shell of the convertible plug  236  or the binding attachment plate  224  to provide a lightweight inexpensive seal. The foam insert could be glued in place to keep it secure. The foam insert would naturally shed ice buildup. The ice would crack and shed off as the foam deflects and springs back into original position.  
         [0204]    Third Embodiment—Convertible Ski Shoe  
         [0205]    Referring to FIG. 20, there is shown a convertible ski shoe  300  of the third embodiment of the present invention, which is adapted for wearing on either the right foot or left foot. It is to be understood that the convertible ski shoe  300  is but one of a pair of the convertible ski shoes of the third embodiment, the other of that same pair being a left/right mirror image of the convertible ski shoe  300 . As will be described, FIGS. 20, 21, and  21 A show the convertible ski shoe  300  in a ski mode configuration. FIGS. 22, 23, and  23 A show the convertible ski shoe  300  in snowshoe mode.  
         [0206]    As best shown in FIGS. 24 and 25, a body  302  of the convertible ski shoe  300 , while unitary in construction, may be thought of as being comprised of five portions, including a center portion  302   a , a snowshoe mode forward portion  302   b , a ski mode forward portion  302   c , the snowshoe mode nose portion  302   d , and a ski mode nose portion  302   e . As best seen in FIG. 24, outer beams  304  are contained in the narrow center portion  302   a  around an aperture  306 . The outer beams  304  are proportioned to transition the bending, shear and twist loads from the snowshoe mode forward portion  302   c  to the ski mode forward portion  302   c . The snowshoe mode nose portion  302   d  that forms the transition to a forwardmost snowshoe point  308 , is curved upward as best-shown in FIG. 24 and is styled with an optional bear claw arch  310  pattern. The ski mode nose portion  302   e  that transitions as shown in FIG. 24 to a forwardmost ski point  312 , is curved upward and insures that the body  302  stays on top of the snow surface and rides smoothly over small obstacles or choppy ice and snow. The shape of the various portions can be changed and styled in various ways without changing or sacrificing the basic function of the convertible ski shoe  300 .  
         [0207]    The convertible ski shoe  300  has two primary modes of operation. FIG. 20 shows the convertible ski shoe  300  assembled in a ski mode. FIG. 22 shows the same parts rearranged and reconfigured in a snowshoe mode.  
         [0208]    Referring to FIG. 25, a primary snow contact surface  314  of the body  302  makes contact with a surface over which the wearer is traversing. In soft snow or powder, a secondary snow contact surface or “wings”  318  will also make contact with the snow surface. The overall body  302  can be proportioned to have sufficient area to keep the device floating up in soft snow or deep powder while in ski mode or providing sufficient area to prevent sinking in snowshoe mode. The combination of primary  314  and secondary snow contact surfaces  318  will allow a short ski design, as depicted here, to act similarly to a long ski. Current narrow short ski designs are not functional in deep powder conditions because of a lack of sufficient lift surface area.  
         [0209]    Since the secondary snow contact surface  318  is offset from the primary snow contact surface  314 , both surfaces can be nearly flat and parallel with respect to a ground plane  316  while allowing the convertible ski shoe to freely roll form side to side. In snowshoe mode, the primary snow contact surface  314  will sink into soft snow first. The secondary snow contact surface  318  will provide enough extra support to keep the user from sinking. The secondary snow contact surface  318  is almost parallel with the ground and will not tend to wedge into the snow as a result. This geometry also works to prevent wedging and lifting the skier in ski mode.  
         [0210]    Referring to FIGS. 20, 22,  28 ,  29 ,  31 A- 31 D, and  32 A- 32 D, the body  302  is connected to a convertible plug  324  with two coaxial pivot pins  326 . The pivot pins  326  also connect a binding attachment plate  328  to the convertible plug  324 . Rolling motion is imparted by the foot through the pivot pins  326  and into the body  302 . This rolling motion causes either of two inner edges  330  to dig into the snow for directional control similar to existing short or long ski designs. A roll angle is sufficient to allow this rolling motion to occur without interference from the wings  318 . In case of extreme rolling due to a fall or extreme slopes, one of two outside edges  334  can cause the inner edge to lift off the snow surface. The inner edges  330  are simply sharp corners of the parent material of the brake ski body  202 . Molded in metal inserts could be used to improve the cutting action of the edges if more control is desired especially on ice. However, if extreme roll conditions are experienced and the outside edges cause the inner edges to pry off of the surface, a loss of control could result. If the two edges are similar in construction and geometry, then they will both perform similarly, and a surprise loss of control will not be experienced. Therefore, it is recommended that both inner  330  and outer edges  334  have optional inserts or have similar geometry and material. The outer edges  334  as depicted are not optimum and have a large gentle radius and an edge that is not straight and parallel to the inner edges  330 .  
         [0211]    The body  302  can be constructed a number of ways, the preferred one being a two piece hollow design comprising an upper and lower shell preferably constructed from a reinforced injection molded plastic. Injection molded parts minimize the touch labor required to set up each part. The reinforcement is preferably a longer fiber variety for maximum strength, stiffness, and damage tolerance at minimal weight. The two halves preferably have a snap fit design where plastic snap elements permanently lock the two halves together. Once the two halves lock together, they act as an integral closed cell box. Using shear bosses would insure that the two halves would act as a single torque box. This manufacturing method would also be consistent with the other parts. Local stiffeners and internal ribs may be used to internally stiffen the skins of the shells. Local areas of higher stress could be strengthened by an increase in thickness. An alternate method to assemble the halves would be to secure them together with fasteners or screws spaced periodically around the perimeter.  
         [0212]    The body  302  could also alternately be constructed as described above, except the snap feature(s) could be replaced with a bond or welding. The body  302  could also alternately be constructed as a one piece foam filled or hollow part having a skin material, such as epoxy-bonded fiberglass, carbon or a metallic material, such as aluminum, disposed thereover. The skin material could form a bonded assembly with an internal foam core and could be a wet lay up over a foam core to save weight. An alternate means of manufacture would involve some form of resin transfer molding or vacuum assist resin transfer molding of resin into a closed cavity mold with dry preform broad goods over an internal mandrel. A hollow design could also be produced using a rotomolding process.  
         [0213]    Referring to FIGS. 24, 25,  28 , and  29 , a ski mode toe surface  336  of the body  302  and a snowshoe mode toe surface  338  are shaped not to interfere and contact with corresponding end surfaces  340  of the convertible plug  324 . A stop located on the convertible plug  324  will contact the body  202  only in ski mode. This contact will prevent a toe end portion  324   b  of the convertible plug  324  from digging into the snow surface as the skier leans forward and will prevent a sudden deceleration or loss of control. In snowshoe mode the convertible plug is flipped over and the stop will pass unrestricted through a stop slot  344  in the body  302 . This will insure unrestrained fully articulating toe and heel engagement in snowshoe mode. If the ski mode toe surface  336  and the snowshoe mode toe surface  338  of the body  202  and the with their corresponding end surfaces  340  of the convertible plug  324  are radiused with the center at a pivot axis, a tight fit will insure that the gap is minimized and foreign objects can not easily get wedged or trapped.  
         [0214]    As illustrated in FIGS.  31 A- 31 D and  32 A- 32 D, the convertible plug  324  is attached to the body  302  by means of the two coaxial pivot pins  326 . The pivot pins  326  are mounted along a transverse “Y” axis through pivot holes  348  (FIGS. 24, 25) in each of the two outer beams  304  of the body  302  and corresponding pivot holes  350  (FIGS. 28, 29) in the convertible plug  324 . As shown in FIG. 29, each pivot pin  326  engages through two lugs, an outer lug  352  and an inner lug  354 . The pivot pin  326  can slide partially out of the convertible plug  324  by backing out of the inner lug  354  while remaining engaged in the outer lug  352 . When the pivot pin  326  is partially released, it also clears a lug hole  356  (FIGS. 28, 29) and releases a binding plate release lug  358  (FIG. 27) and the binding attachment plate  328 . The convertible plug  324  can now be flipped over to change modes. The binding attachment plate  328  is attached or bound to the foot and remains attached to the foot during a conversion to ski mode from snowshoe mode or vice-versa. The foot is rotated so that the toe points to the opposite end of the ski shoe body  302 . Then the binding plate release lugs  358  are inserted back through the lug holes  356  on the reversed side of the convertible plug  324 . The two pivot pins  326  are then pushed back into full engagement and the binding attachment plate  328  is again secured to the convertible plug  324 .  
         [0215]    Referring to FIG. 30, the pivot pin  326  is detailed as a quick release pin, although many other types of shear pins would work in this application. A simple pivot pin similar to the one shown for the brake ski  300  would work if one end were modified to make it removable. A simple spring clip (not shown) could be slipped through a small hole transverse to the longitudinal axis of the pivot pin or a self locking wing nut could be used. If a one piece removable pin were used, more time and effort would be required to realign the convertible plug  324  after it is flipped and then reattached to the binding attachment plate  328 . A single removable pivot pin could be placed in any number of multiple pivot hole positions (not shown) located forward and aft of each other along the longitudinal axis of the ski shoe to customize the braking or gripping response. This optional design where there are multiple positions for a single removable pivot pin that passes through the entire convertible plug  324  would be the best arrangement for an initial prototype to investigate overall performance of ski mode and snowshoe mode geometric relationships.  
         [0216]    The convertible plug  324  is free to rotate about the pivot axis. A pin height is set to keep the pivot pin  326  clear of the ground plane when the body  302  is rolled to either side for cutting in ski mode or walking transverse along inclines in snowshoe mode. The pivot pin is supported by lugs  362  that hang down from the outer beams  304  on the body  302 . The pivot is shown roughly at the middle of the convertible plug  324 , so that the convertible plug will rotate and have equal clearance between the end surface  340  and the ski mode toe surface  336  and the snowshoe mode toe surface  338 .  
         [0217]    To retain the convertible plug  324  while the ski shoe is being converted, the recommended and preferred pin arrangement would be as shown in FIG. 32A- 32 D. Two short pivot pins are inserted from both left and right sides through pivot holes  364  on lugs  362  hanging down form the outer beams  304  on the body  302 . This pivot hole is aligned with the pivot holes  350  going through the outer and inner lugs  352 ,  354 , in the convertible plug  324 . The pivot hole  364  on the binding plate release lug  358  on the binding attachment plate  328  is sandwiched and secured between the outer and inner lug  352 ,  354 , on the convertible plug  324 .  
         [0218]    Referring now to FIG. 30, each pivot pin  326  is a quick release pin comprising a hollow shaft  368  that carries shear loads and a button  370  that extends inside of the hollow portion of the hollow shaft  368 . The button  370  is springloaded and when pushed in allows retaining ball(s)  374  to displace inside the hollow shaft  368 . Leverage is gained by placing the index middle fingers behind and around a handle  376  while pushing in the button  370  with the thumb. Once the retaining balls are displaced inside the hollow shaft  368 , the pivot pin assembly will slide out of the pivot holes until an optional key  378  contacts one of the lugs  362  on one side of the body  302 . The pivot hole  350  in the convertible plug  324  could have an additional groove (not shown) that allows the optional key  378  to pull through the pivot hole only at one alignment angle. The optional key  378  is positioned so that it passes through the groove (not shown) and contacts the respective lug  362  on the body  302 . This stop position is a safety feature that simply provides for extra pin engagement security and is entirely optional. If the convertible plug  324  needs to be released in order to use the crampon feature separately, the pivot pin handle  376  is rotated to some other angle to align the optional key  378  the release groove (not shown) in the lug  362  of the body  302 . Therefore, an extra twist is required to fully release the pivot pin  326 .  
         [0219]    A simpler way to retain the quick release pin  326  without an optional key  378  is to allow and align the retaining balls  364  to snap and lock into back to back chamfers (not shown) on common faces of the respective lug  362  and an outer flange  380  (FIGS. 26, 27). Chamfering is much easier to tool than a feature internal to and locked inside a part. A push of the button  370  would release the ball(s)  374  and the pivot pin  326  would slide out. An optional lanyard (not shown) could be used to retain a loose pin. This lanyard could be an elastic “bungee cord” that pulls itself back into the pin when not used to prevent a possible entanglement or snagging.  
         [0220]    Referring now to FIGS. 26, 27, and  22 , it can be seen that the binding attachment plate  328 , while unitary in construction, may be thought of as comprising three portions, including a center portion  328   a , a toe portion  328   b , and a heel portion  328   c . As best seen in FIG. 27, the center portion  328   a  extends along the region of constant width. The toe portion  328   b  extends along the end transition radius to a heel surface  382 . If the skier wants to slow down or stop, weight is simply shifted to the heel portion  328   c  of the binding attachment plate  328 . The heel portion  328   c  will then push down into the surface of the snow through the convertible plug  324  and cause the snow to displace downward and to the side. The energy required to displace the snow will cause the skier to slow down and finally stop. In snowshoe mode, weight is simply shifted either to the toe portion  328   b  or heel portion  328   c  to cause the convertible plug  324  to rotate and engage teeth  382  for gripping and traction. The width of the binding attachment plate  328  is wider than the foot to allow a full range of motion of the foot in snowshoe mode. The binding attachment plate  328  and either a ski side  328   a  or snowshoe side  324   b  of the convertible plug  324  nest together in the same way by contact at plug interface surfaces  386  on the binding attachment plate  328 .  
         [0221]    The binding attachment plate  328  can be constructed in a number of ways, the preferred one being a one piece injection molding made from a reinforced plastic. Injection molded parts minimize the touch labor required to set up each part. The reinforcement could be a longer fiber variety for maximum strength, stiffness, and damage tolerance at minimal weight. Local stiffeners and ribs (not shown) are used to stiffen the skins of an outer shell. The ribs are much smaller and simpler than other ribs shown for the other designs because the binding attachment plate  328  works in conjunction with the convertible plug  324  to form an effective closed box structure. A closed box structure is naturally the most efficient section for maximum torsional stiffness. Optional binding attach bosses and binding attach holes are not shown, but could be detailed in a deck  392  to receive standard snowboard style bindings. The snowboard style bindings are highly recommended because of their excellent support of the foot and ankle. Other types of bindings, including various strap arrangements can be mounted a number of ways through either forward strap binding holes  393   a  or aft strap binding holes  393   b  as best shown in FIG. 26. The deck  392  and outer flange  380  of the binding attachment plate  328  can support any number and arrangements of strap holes or additional flanges or other features that would be molded into or would extend above the surface of the deck  392 . Various other types of ski, telemark, cross-country, snowshoe, or Rottefella bindings can be mounted to standard mounting holes and inserts located on the surface of the deck  392 . An optional non-skid surface  395  feature is shown on the deck surface to keep the foot from sliding around.  
         [0222]    Referring now to FIGS. 28, 29, and  23 A, it can be seen that the convertible plug  324 , while unitary in construction, may be thought of as being comprised of four portions, including a center portion  324   a , an end portion  324   b , a ski side  324   c  and a snowshoe side  324   c . As best seen in FIG. 28, the center portion  324   a  extends along the region of constant width. The end portion  324   b  extends along the end transition radius to the end surface  340 , the ski side  324   b  also has a primary ski surface  396   b  that makes contact with the surface being traversed by the user. In soft snow or powder, the secondary ski surface or “wings”  398  will also make contact with the snow surface as described for the body  302 . When the skier wants to ski without braking action or restraint, weight is shifted forward, and the binding attachment plate  328  rotates into the a position in which the primary and secondary ski surfaces  396 ,  398 , of the convertible plug  324  align themselves with the primary and secondary surfaces  314 ,  318 , of the body  302 . In this position, the convertible ski  300  offers very little resistance to sliding.  
         [0223]    The snowshoe side  324   c  of the convertible plug  324  has an outer flange  398   a  with teeth  398   b  formed on the edge. These teeth  398   b  provide traction and gripping. Although the teeth are best shown in FIG. 28 as integral with the rest of the convertible plug material, an optional metal or other material insert could be used in an injected molded part to make the teeth edges more durable and effective. For cost considerations, however, the integral material approach has merit.  
         [0224]    The convertible plug  324  can be constructed a number of ways, the preferred one being a one piece injection molding made from a reinforced plastic. Injection molded parts minimize the touch labor required to set up each part. The reinforcement could be a longer fiber variety for maximum strength, stiffness, and damage tolerance at minimal weight. The outer flange  398   a , the end surface  340 , lateral ribs  398   d , and the thicker pivot hole rib  398   e  would be used to stiffen the primary ski surface  396  and wings  398 . The lateral ribs  398   d  are much smaller and simpler than other ribs shown for the other designs because the binding attachment plate  328  works in conjunction with the convertible plug  324  to form an effective closed box structure.  
         [0225]    To prevent snow and ice from accumulating in the cavities of the snowshoe side  324   c  of the convertible plug  324  or the binding attachment plate  328  and adding unnecessary weight to the device, an optional stiff closed foam insert material (not shown) could be molded or cut to fit snugly into the open cavities between the ribs and the shell of the convertible plug  324  or the binding attachment plate  328  to provide a light weight inexpensive seal. The foam insert could be glued in place to keep it secure.  
         [0226]    Fourth Embodiment—Dual Bridge Convertible Ski Shoe  
         [0227]    Referring to FIG. 33, there is shown a dual bridge convertible ski shoe  400  of the forth embodiment of the present invention, which is adapted for wearing on either the right foot or left foot. It is to be understood that the dual bridge convertible ski shoe  400  is but one of a pair of the dual bridge convertible ski shoes of the fourth embodiment, the other of that same pair being a left/right mirror image of the dual bridge convertible ski shoe  400 .  
         [0228]    Referring now to FIGS.  33 - 38 B, it can be seen that the dual bridge convertible ski shoe body  402 , while unitary in construction, may be thought of as being comprised of five portions, including a center portion  402   a , a snowshoe mode forward portion  402   b , a ski mode forward portion  402   c , a snowshoe mode nose portion  402   d , and a ski mode nose portion  402   e . As best seen in FIG. 38A, the center portion  402   a  extends along a cutout region. Outer beams  404  are contained in the narrow center portion  402   a  around an aperture  406 . The outer beams  404  are proportioned to transition the bending, shear and twist loads from the snowshoe mode forward portion  402   c  to the ski mode forward portion  402   c . The snowshoe mode nose portion  402   d  that forms the transition to a forwardmost snowshoe point  408 , is curved upward as best-shown in FIG. 38B and is styled with an optional bear claw arch  410  pattern. The ski mode nose portion  402   e  that transitions as shown in FIG. 37A to a forwardmost ski point  412 , is curved upward and insures that the body  402  stays on top of the snow surface and rides smoothly over small obstacles or choppy ice and snow. The shape of the various portions can be changed and styled in various ways without changing or sacrificing the basic function of the convertible ski shoe  400 .  
         [0229]    The dual bridge convertible ski shoe  400  has two primary modes of operation. FIGS.  33 - 34 A shows the dual bridge convertible ski shoe  400  assembled in a ski mode. FIGS.  35 - 36 A shows the same parts rearranged and reconfigured in a snowshoe mode.  
         [0230]    A primary snow contact surface  414  of the body  402  makes contact with the surface being traversed. In soft snow or powder, the secondary snow contact surface or “wings”  418  will also make contact with the snow surface. The overall body  402  can be proportioned to have sufficient area to keep the device floating up in soft snow or deep powder while in ski mode or providing sufficient area to prevent sinking in snowshoe mode. The combination of primary and secondary snow contact surfaces  414 ,  418 , will allow a short ski design, as depicted here, to act similarly to a long ski. Current narrow short ski designs are not functional in deep powder conditions because of a lack of sufficient lift/surface area.  
         [0231]    The secondary snow contact surface  414  is offset from the primary snow contact surface  418 . The primary snow contact surface is nearly flat and parallel with respect to the surface being traversed. However, the secondary snow contact surface  418  is not parallel with the ground plane  416 . The secondary snow contact surface angle shows the wedge shape formed by the two secondary snow contact surfaces on each side of a fin  423 . The offset between the primary and secondary contact surfaces does allow the dual bridge convertible ski shoe  400  to freely roll from side to side. In snowshoe mode, the primary snow contact surface  414  will sink into soft snow first. The secondary snow contact surface  418  will provide enough extra support to keep the user from sinking. The secondary snow contact surface  418  is not parallel with the ground and may tend to wedge into the snow as a result. The overall width or length may have to be adjusted to compensate for this tendency. The extra surface area may also be required in ski mode to provide sufficient lift.  
         [0232]    As shown best in FIGS.  44 A- 44 C and  45 A- 45 D, the body  402  is connected to a convertible plug  424  with a pivot pin  426 . Rolling motion is imparted by the foot through the pivot pins  426  and into the body  402 . This rolling motion causes either of two inner edges  428  to dig into the snow for directional control similar to existing short or long ski designs. A roll angle is sufficient to allow this rolling motion to occur without interference from the wings  418 . In case of extreme rolling due to a fall or extreme slopes, one of two outside edges  430  can cause the inner edge to lift off the snow surface. The inner edges  428  are simply sharp corners of the parent material of the body  402 . Molded in metal inserts could be used to improve the cutting action of the edges if more control is desired especially on ice. However, if extreme roll conditions are experienced and the outside edges cause the inner edges to pry off of the surface, a loss of control could result. If the two edges are similar in construction and geometry, then they will both perform similarly, and a surprise loss of control will not be experienced. Therefore, it is recommended that both inner  428  and outer edges  430  have optional inserts or have similar geometry and material. The outer edges  430  as depicted are not optimum and have a large gentle radius and an edge that is not straight and parallel to the inner edges  428 .  
         [0233]    Referring to FIGS. 37, 37A,  38 , and  38 A, the body  402  can be constructed a number of ways, the preferred one being a two piece hollow design comprising an upper and lower shell preferably constructed from a reinforced injection molded plastic. Injection molded parts minimize the touch labor required to set up each part. The reinforcement is preferably a longer fiber variety for maximum strength, stiffness, and damage tolerance at minimal weight. The two halves preferably have a snap fit design where plastic snap elements permanently lock the two halves together. Once the two halves lock together, they act as an integral closed cell box. Using shear bosses would insure that the two halves would act as a single torque box. This manufacturing method would also be consistent with the other parts. Local stiffeners and internal ribs may be used to internally stiffen the skins of the shells. Local areas of higher stress could be strengthened by an increase in thickness. An alternate method to assemble the halves would be to secure them together with fasteners or screws spaced periodically around the perimeter.  
         [0234]    The body  402  could also alternately be constructed as described above, except the snap feature(s) could be replaced with a bond or welding. The body  402  could also alternately be constructed as a one piece foam filled or hollow part having a skin material, such as epoxy-bonded fiberglass, carbon or a metallic material, such as aluminum, disposed thereover. The skin material could form a bonded assembly with an internal foam core and could be a wet lay up over a foam core to save weight. An alternate means of manufacture would involve some form of resin transfer molding or vacuum assist resin transfer molding of resin into a closed cavity mold with dry preform broad goods over an internal mandrel. A hollow design could also be produced using a rotomolding process.  
         [0235]    Referring to FIGS. 37, 37A,  41 ,  41 A,  42 , and  42 A, a ski mode toe surface  432  and a snowshoe mode toe surface  434  of the body  402  are shaped not to interfere and contact with their corresponding end surfaces  435  of the convertible plug  424 . A stop located on the convertible plug  424  will contact the body  402  only in ski mode. This contact will prevent a toe end portion  424   b  of the convertible plug  424  from digging into the snow surface as the skier leans forward and will prevent a sudden deceleration or loss of control. In snowshoe mode the convertible plug is flipped over and the stop will pass unrestricted through a stop slot  438  in the body  402 . This will insure unrestrained fully articulating toe and heel engagement in snowshoe mode. If the ski mode toe surface  432  and the snowshoe mode toe surface  434  and their corresponding end surfaces  435  of the convertible plug  424  are radiused with the center at a pivot axis, a tight fit will insure that the gap is minimized and foreign objects can not easily get wedged or trapped.  
         [0236]    As shown in FIGS.  44 A- 44 C and  45 A- 45 D, the convertible plug  424  is attached to the body  402  by means of a pivot pin  426 . The pivot pin  426  is mounted along a transverse “Y” axis through pivot holes  442  in each of the two outer beams  404  of the body  402  and corresponding pivot holes  444  contained in the convertible plug  424 . The convertible plug  424  can be flipped over to change modes without any manipulation of the pivot pin  426 . Binding attachment plates  446  are attached or bound to the foot and remains attached to the foot during a conversion to ski mode from snowshoe mode or vice-versa. The foot is rotated so that the toe points to the opposite end of the ski shoe body  402 .  
         [0237]    Referring to FIGS. 39, 39A,  40 , and  40 A, the binding attachment plates  446  are adjustable to one of five positions as best shown in FIG. 42A. There are three fingers on each side of each binding attachment plate  446 . The center finger is a shear pin  448 , which engages into one of the pin holes  450  in the convertible plug  424 . The fit between the pin hole  450  and the shear pin  448  is tight. The engagement prevents the binding attachment plate  446  from sliding fore or aft or laterally on the convertible plug  424 . The other two fingers are binding plate release springs  451 . The binding plate release springs  451  have a barb on each end that snaps or springs back and then locks into two pin holes  450  on each side of the shear pin  448 . The binding plate release springs  451  are designed to react tension in the vertical direction between the convertible plug  424  and the binding attachment plate  446 . The fit between the binding plate release spring  451  and the pin hole  450  is loose enough to allow the larger barb to pass through the pin hole  450 . The binding attachment plates  446  can be released from the convertible plug  424  by reaching underneath the convertible plug  424  and inserting the index finger and thumb into the finger access slot  452  and squeezing the two binding plate release springs  451  together and allowing the barbs to pop back through the pins holes  450 .  
         [0238]    Referring to FIGS. 43 and 43A, the pivot pin  426  is detailed as a quick release pin, although many other types of shear pins would work in this application. A simple pivot pin similar to the one shown for the brake ski  100  would work. A removable pivot pin could be made from a simple spring clip (not shown) and could be slipped through a small hole transverse to the longitudinal axis of the pivot pin or a self locking wing nut could be used. A single removable pivot pin could be placed in any number of multiple pivot hole positions (not shown) located forward and aft of each other along the longitudinal axis of the ski shoe to customize the braking or gripping response. This optional design where there are multiple positions for a single removable pivot pin that passes through the entire convertible plug  424  would be the best arrangement for an initial prototype to investigate overall performance of ski mode and snowshoe mode geometric relationships. This design alternate would require the pivot pin to be repositioned during transition between modes if any location were used other than at the center of the convertible plug  424 .  
         [0239]    The convertible plug  424  is free to rotate about the pivot axis. The pin height is set to keep the pivot pin  426  clear of the ground plane when the body  402  is rolled to either side for cutting in ski mode or walking transverse along inclines in snowshoe mode. The pin height is higher for this design to allow the convertible plug  424  geometry to properly match the binding attachment plate  446  geometry. The pivot axis is shown roughly at the middle of the convertible plug  424 , so that the convertible plug will rotate and have equal clearance between the end surface  435  and the ski mode toe surface  432  and the snowshoe mode toe surface  434 .  
         [0240]    Referring now to FIG. 43A, each pivot pin  426  is a quick release pin comprising a hollow shaft  458  that carries shear loads and a button  460  that extends inside of the hollow portion of the hollow shaft  458 . The button  460  is springloaded and when pushed in allows retaining ball(s)  464  to displace inside the hollow shaft  458 . Leverage is gained by placing the index middle fingers behind and around a handle  466  while pushing in the button  460  with the thumb. Once the retaining balls are displaced inside the hollow shaft  458 , the pivot pin assembly will slide out of the pivot holes until the optional key  468  contacts edge of the pivot hole  442  in the outer beam  404  on one side of the body  402 . The pivot hole  444  in the convertible plug  424  could have an additional groove (not shown) that allows the optional key  468  to pull through the pivot hole only at one alignment angle. The optional key  468  is positioned so that it passes through the groove (not shown) and contacts the edge of the pivot hole  42  in the outer beam  404  on the body  402 . This stop position is a safety feature that simply provides for extra pin engagement security and is entirely optional. If the convertible plug  424  needs to be released in order to use the crampon feature separately, the pivot pin handle  466  is rotated to some other angle to align the optional key  468  with a release groove (not shown) in the pivot hole  442  in the outer beam  404  on the body  402 . Therefore, an extra twist is required to fully release the pivot pin  426 .  
         [0241]    A simpler way to retain the quick release pin  426  without the optional key  468  is to allow and align the retaining balls  464  to snap and lock into back to back chamfers (not shown) on the common faces of the edge of the pivot hole  442  in the outer beam  404  on one side of the body  402  and an outer flange  470  (FIG. 42) of the convertible plug  424 . Chamfering is much easier to tool than a feature internal to and locked inside a part. A push of the button  460  would release the ball(s)  464  and the pivot pin would slide out. An optional lanyard (not shown) could be used to retain a loose pin. This lanyard could be an elastic “bungee cord” that pulls itself back into the pin when not used to prevent a possible entanglement or snagging. An alternate design would feature a permanent non-removable pin which would reduce cost.  
         [0242]    Referring now to FIG. 39, 39A, and  40 , it can be seen that the binding attachment plate  446 , while unitary in construction, may be thought of as being comprised of two portions, including a straight portion  446   a , and the end portion  446   b . As best seen in FIG. 39A, the straight portion  446   a  extends along the region of constant width. The end portion extends along the end transition radius to the opposite edge of the part. There are two binding attachment plates  446 . One of them is attached to the toe of the foot and the other to the heel. If the skier wants to slow down or stop, weight is simply shifted to the binding attachment plate  446  attached on the heel. This binding attachment plate  446  attached to the heel will then will push down into the surface of the snow through the convertible plug  424  and cause the snow to displace downward and to the side. The energy required to displace the snow will cause the skier to slow down and finally stop. In snowshoe mode weight is simply shifted to either of the two binding attachment plates to cause the convertible plug to rotate and engage teeth  472  (FIG. 42) for gripping and traction. The width of the binding attachment plate  446  is wider than the foot to allow a full range of motion of the foot in snowshoe mode. The binding attachment plate  446  and either a ski side  424   c  or snowshoe side  424   d  of the convertible plug nest together the same way by contact at plug interface surfaces  474  on the binding attachment plate  446 .  
         [0243]    Referring to FIGS. 39, 39A,  40 ,  40 A, the binding attachment plate  446  can be constructed a number of ways, the preferred one being a one piece injection molding made from a reinforced plastic. Injection molded parts minimize the touch labor required to set up each part. The reinforcement could be a longer fiber variety for maximum strength, stiffness, and damage tolerance at minimal weight. Other types of bindings, including various strap arrangements can be mounted a number of ways through strap binding holes  476  as best shown in FIGS. 39A and 40. A deck  477  (FIG. 39) and outer flange  478  of the binding attachment plate  446  can support any number and arrangements of strap holes or additional flanges or other features that would be molded into or would extend above the surface of the deck  477 . Various other types of telemark, cross-country, snowshoe, or Rottefella bindings can be mounted to standard mounting holes and inserts located on the surface of the deck  477 . An optional non skid surface  480  feature is shown on the deck surface to keep the foot from sliding around.  
         [0244]    Referring now to FIGS. 41, 41A, and  42 , it can be seen that the convertible plug  424 , while unitary in construction, may be thought of as being comprised of four portions, including a center portion  424   a , end portions  424   b , a ski side  424   c  and a snowshoe side  424   d . As best seen in FIG. 42, the center portion  424   a  extends along a region of constant width. The end portion  424   b  extends along the end transition radius to the end surface  435 . As best shown in FIG. 41A, the ski side  424   c  also has a primary ski surface  481  that makes contact with the surface being traversed. In soft snow or powder, the secondary ski surface or “wings”  483  will also make contact with the snow surface as described for the body  402 . When the skier wants to ski without braking action or restraint, weight is shifted forward, and the binding attachment plate  446  rotates into the a position in which the primary and secondary ski surfaces  481 ,  483 , of the convertible plug  424  align themselves with the primary and secondary surfaces  481 ,  483 , of the body  402 . In this position, the convertible ski  400  offers very little resistance to sliding.  
         [0245]    Referring to FIG. 42, the snowshoe side  424   d  of the convertible plug  424  has an outer flange  470  with teeth  472  formed on the edge. These teeth  472  provide traction and gripping. Although the teeth are best shown in FIG. 42 as integral with the rest of the convertible plug material, an optional metal or other material insert could be used in an injected molded part to make the teeth edges more durable and effective. For cost considerations, however, the integral material approach has merit.  
         [0246]    The convertible plug  424  can be constructed a number of ways, the preferred one being a one piece injection molding made from a reinforced plastic. Injection molded parts minimize the touch labor required to set up each part. The reinforcement could be a longer fiber variety for maximum strength, stiffness, and damage tolerance at minimal weight. The outer flange  470 , end surface  435 , ribs  488 , and the thicker longitudinal rib  490  would be used to stiffen the primary ski surface  481  and wings  483 .  
         [0247]    To prevent snow and ice from accumulating in the cavities of the snowshoe side  424   d  of the convertible plug  424  or the binding attachment plate  446  and adding unnecessary weight to the device, an optional stiff closed foam insert material (not shown) could be molded or cut to fit snugly into the open cavities between the ribs and the shell of the convertible plug  424  or the binding attachment plate  446  to provide a light weight inexpensive seal. The foam insert could be glued in place to keep it secure.  
         [0248]    Fifth Embodiment—Smooth Bottom Convertible Ski Shoe  
         [0249]    FIGS.  46 - 49 C,  52 - 56 , and  57 - 58 B, as well as FIGS.  59 - 79 , illustrate a fifth embodiment, a smooth bottom convertible ski shoe  500 , which combines all the benefits of the first, second and third embodiments into a single design. FIGS.  46 - 49 C illustrate the smooth bottom convertible ski shoe  500  in ski mode configuration. FIGS.  52 - 56  illustrate the smooth bottom convertible ski shoe  500  in snowshoe mode configuration. FIGS.  57 - 58 B illustrate the smooth bottom convertible ski shoe  500  in glide mode configuration. The smooth bottom convertible ski shoe  500  is a versatile device that enables a person to travel at the most efficient rate across a wide range of winter landscape. The design of the smooth bottom convertible ski shoe has been enhanced to eliminate the underslung lugs as shown in FIGS. 24 and 25 illustrating the convertible ski shoe of the third embodiment. The smooth bottom convertible ski shoe  500  may be quickly transformed from a fast downhill ski into an all-terrain snowshoe in seconds.  
         [0250]    Referring to FIG. 46, to accomplish this transformation, the user reaches down and releases one or more binding plate locks. A binding plate assembly  503  (FIGS.  69 - 71 ) stays attached to the binding and foot as the foot is lifted up. A convertible plug  504  is attached to a body  506  of the smooth bottom convertible ski shoe  500  by means of two coaxial pivot pin assemblies  508 . A convertible plug assembly  510  is then flipped over or converted. A foot is then reversed in direction and reinserted into an opposite side or snowshoe side  504   d  of the convertible plug assembly  510  and the ski is transformed into a snowshoe. The binding plate locks  502  are then secured.  
         [0251]    Any number of different kinds of standard bindings can be attached to a deck  516  of a binding plate  518 . The preferred type of binding would a standard snowboard type, such as the K-2 Clicker step-in standard or high back system. Although, any number of Burton binding systems, telemark, cross-country, short ski, such as Solomon Snow Blade, or ski shoe bindings or crampons, such as Atlas Mountain Tracker, could also be adapted and mounted. The snowboard bindings would be adapted for use with the foot mounted fore and aft like a standard ski, instead of transverse as on a snowboard. The more compliant boots used for snow boarding would offer a good balance between flexibility and rigidity for control. The snowboard bindings can be adjusted to allow the optimum foot angle for pigeon-toed or bow-legged people to align their ski shoes straight. The cross-country and snowshoe bindings would be more difficult to control because of their lack of foot restraint. The short ski bindings are designed for use with regular ski boots, which are very rigid for comfortable walking. Other types of bindings, including various strap arrangements can be mounted a number of ways through strap binding holes not detailed.  
         [0252]    As illustrated in FIGS.  59 - 64 , the body  506  of the smooth bottom convertible ski shoe  500 , while unitary in construction, may be thought of as being comprised of three portions, including a center portion  506   a , a snowshoe mode forward portion  506   b , and a ski mode forward portion  506   c . In snowshoe mode, most of the body length is located behind a pivot axis  520  (FIG. 61A) of the foot. This insures that the back of the snowshoe, also the ski mode forward portion  506   c , falls against the ground so that the snowshoe mode forward portion  506   b  of the body  506  is lifted up to make it easier to step forward into soft snow. In ski mode, the ski mode forward portion  506   c  extends out further than the back or snowshoe mode forward portion  506   b . This configuration is thus optimized for control while skiing.  
         [0253]    The smooth bottom convertible ski shoe  500  can ski in light powder because the body  506  has enough lift surface area to keep a skier floating up. The lift area is comprised of the primary snow contact surfaces  522 ,  523 , secondary snow contact surfaces  524 ,  525 , and optional additional levels, such as the tertiary snow contact surface  526 . The additional drag from the underslung lugs of the convertible ski shoe, as shown in FIGS. 24 and 25 above, has been eliminated. The smooth bottom convertible ski shoe  500  is small, light, inexpensive, and compact. It facilitates skiing with speed and confidence while improving safety, even when skiing down tight narrow trails or glade runs between trees, because braking action is available by rotating the binding plate and convertible plug assemblies  503  and  510  about the pivot axis  520  by leaning back on the feet. This braking action, which is illustrated in FIGS.  50 A- 50 E and  51 , can be used for control and steering without using inner edge(s)  528  of the ski shoe by cutting back and forth or snowplowing. It is easier to learn because the skier&#39;s reflexes automatically result in braking action without the need to learn new technique. A skier slows down when naturally leaning back on his feet.  
         [0254]    In ski mode, the convertible plug assembly  510  would normally be prevented from rotating forward or toe down about the pivot axis  520 . This would prevent excessive and possibly uncontrolled deceleration. There are several redundant features that prevent toe down rotation in ski mode. Although only one is required for safety, several different options are detailed here. The first is a pair of hard stops  530  and  531  on the convertible plug  504  and body  506  respectfully that contact each other at a negative pitch angle [ 532 -NOT SHOWN] limit. The second is to install a plug rotation limiter pin  534  in one of a plurality of stop holes  536  (FIGS.  62 B and  63 A- 63 B), which may include a fixed stop hole, a slotted stop hole, and a store stop hole, position in the body  506 . When the plug rotation limiter pin  534  is installed in a fixed stop hole  536  position, the convertible plug assembly  510  cannot rotate about the pivot axis  520 . The plug rotation limiter pin  534  engages into a stop hole  540  of the convertible plug  504 . This setting also prevents braking action, but may be a preferred setting for some skiers who want the response of a traditional short ski.  
         [0255]    If the plug rotation limiter pin  534  is installed in a slotted stop hole  536 , a limited range of pitch angle motion is allowed. This setting would be useful to allow braking but prevent excessive negative pitch rotation and possible loss of control of the ski shoe and serve as a redundant toe down positive pitch angle stop. The plug rotation limiter pin  534  engages into a ski mode stop slot  542  of the convertible plug  504 . The ski mode stop slot  542  is not shown to fully penetrate the convertible plug  504  so that rigidity is not compromised. This limited heel down pitch angle  532  motion also has a benefit during falls and can help prevent or minimize injuries, including ACL injuries. Ski boots are being developed that provide this extra degree of motion, but providing for it in the ski itself is novel. This approach can be used in the brake ski of the first embodiment and extended to longer ski versions.  
         [0256]    Another ski mode would be to place the plug rotation limiter pin  534  in a store stop hole  536  position. In this position, the convertible plug assembly  510  is free to rotate in the heel down pitch angle until the back of the user&#39;s boot contacts an aperture tube  546  on the body  506 . This extra pitch angle motion may be useful in steep narrow powder runs where the skier can stand comfortably upright and maintain a controlled descent without cutting and accelerating abruptly. The plug rotation limiter pin  534  does not engage the convertible plug  504  when inserted into the store stop hole  536 . In any of the three positions for the plug rotation limiter pin  534 , a handle  548  is secured by snapping it into a pin clip  550 .  
         [0257]    The convertible plug assembly  510  can also be set to provide some controlled degree of toe down pitch angle rotation before hitting a stop in ski mode. This can be used for an optional glide mode, as illustrated in FIGS. 57, 58A, and  58 B, where a binding is used that releases the heel similar to cross-country skis. The toe would pivot slightly forward to allow a grabber feature or shovel to dig in slightly and give the cross-country skier a toe hold with which to push off. The smooth bottom convertible ski shoe  500  may be quickly transformed from a fast, downhill ski into a glide ski for flat, gradual up or down slopes in seconds. To accomplish this transformation, the user reaches down and releases the binding plate lock(s) and removes or backs out the plug rotation limiter pin  534  by popping the handle  548  out of the pin clip  550 . The binding plate assembly  503  stays attached to the binding and foot as the foot is lifted up. The convertible plug assembly  510  is then flipped over or converted with teeth  552  down in the snowshoe mode position (FIGS.  50 - 56 ). The foot is reinserted in the same direction with a toe portion  518   b  of the binding plate  518  pointed toward the ski mode forward portion  506   c  into the opposite side or snowshoe side  504   d  of the convertible plug assembly  504  and the ski is transformed into a glide ski. The binding plate lock(s) are then secured. The plug rotation limiter pin  534  is then reengaged into the glide stop slot  554  and the handle  548  is returned to the pin clip  534 . The glide stop slot  554  is designed to allow some degree of toe down pivot motion about the pivot axis  520  so that the forward teeth  552  can dig into and grip the snow. The glider typically pushes off with the lagging foot, so the toe naturally pushes down on the toe portion  518   b  of the binding plate  518 . Pressure is put on the heel portion  518   c  of the binding plate  518  by the leading or gliding foot. The plug rotation limiter pin  534  is engaged through the slotted stop hole  536  on the body  506  and into the glide stop slot  554  that prevents the convertible plug assembly  510  from rotating at a positive pivot angle. The teeth remain retracted above a ground plane  555  (FIGS. 55A and 55B) and allow drag free gliding.  
         [0258]    The conversion into snowshoe mode is then accomplished simply by removing or backing out the plug rotation limiter pin  534  by popping the handle  548  out of the pin clip  550 . The plug rotation limiter pin  534  can then be stowed in a neutral position by inserting it into the optional store stop hole  536 . In this position, the convertible plug assembly  510  is free to rotate in the toe down or heel down pitch angle until the back or front of the user&#39;s boot contacts the aperture tube  546  on the body  506  (FIGS. 55A and 55B). This extra pitch angle motion is especially helpful on descent where the skier can stand, walk, or run comfortably upright. Other snowshoe designs allow toe down pitch angle motion already, but the smooth bottom convertible ski shoe  500  allows full foot motion about the pivot axis  520 . The plug rotation limiter pin  534  does not engage the convertible plug  504  when inserted into the store stop hole  536 . The smooth bottom convertible ski shoe  500  becomes a fully articulating snowshoe and the user can walk or run up or down steep slopes at any angle with comfort. A conventional snowshoe forces the foot into a zero roll angle with respect to a sloping ground plane  555 . This is especially uncomfortable if the user is not climbing or descending directly up or down a slope but is traversing at an off angle. The smooth bottom convertible ski shoe  500  can freely roll at an angle that allows the user to stand, walk, or run in a comfortable upright position. Therefore, the user maintains maximum control and grip in any slope angle.  
         [0259]    An optional feature of the smooth bottom convertible ski shoe  500  allows the teeth  552  to be adjusted into several different pin heights. Although a production design would not require the multiple heights, the optimal pin height can be determined during testing. To change the height of the convertible plug assembly  510  and binding plate assembly  503 , the pivot pin assemblies  508  are partially backed out of pivot holes  560 . Pivot pins  562  are mounted along a transverse “Y” axis through pivot holes  560  in each of two beams  564  of the body  506  and corresponding primary pivot holes  566  contained in the convertible plug  504 .  
         [0260]    Referring to FIG. 77, this is accomplished by prying each clip keeper  568  over the top of the beam  564 . A clip  569  is then rotated about a clip pivot  570  until it lies along an approximate horizontal plane that is parallel to the ground plane  555 . This motion will cause the attached clip to rotate about a clip retention pin  571  and pull the pivot pin  562  partially out of the pivot hole  560 . A pivot pin slot  572  provides clearance between the clip  569  and pivot pin  562 . The pivot pin  562  backs out of the primary pivot hole  566 , but remains engaged in a pivot hole slot  573 . The convertible plug assembly  510  is now free to lower with respect to the body  506  until the pivot pin  562  is aligned with a secondary pivot hole  574 . The clip  569  is then rotated as the clip pivot  570  is pushed into a clip pivot slot  575  on the body  506 . This prying action forces the pivot pin  562  to engage the secondary pivot hole  574 . The clip keeper  568  is then forced into locked position over the beam  566 . The biting action of the teeth  552  is now more aggressive. The convertible plug  504  must be returned to the original primary position to properly align the primary snow contact surface  522  of the body  506  with the primary ski surface  523  of the convertible plug  504  when going back into ski mode.  
         [0261]    If very tight conditions are encountered such as climbing among snow covered rocks, the combined binding plate/convertible plug assemblies  503 ,  510 , function as crampons and can be released and used as separate devices by pulling the clip  569  out further to withdraw the pivot pin from the pivot hole slot  573 .  
         [0262]    It is to be understood that the smooth bottom convertible ski shoe  500  shown in FIG. 46 is but one of a pair of the smooth bottom convertible ski shoes of the fifth embodiment, the other of that same pair being identical thereto.  
         [0263]    As best illustrated in FIG. 59, the body  506  further includes a snowshoe mode forward pocket  506   d  and a ski mode forward pocket  506   e , which are recesses that stiffen and lighten the body by closing out the aperture tube  546  and perimeter tube  576 . The center portion  506   a  extends along a cutout or aperture  577  region. The outer beams  564  are contained in the narrow center portion  506   a  around the aperture  577 . The outer beams  564  are proportioned to transition the bending, shear and twist loads from the snowshoe mode forward portion  506   b  to the ski mode forward portion  506   c . The snowshoe mode forward portion  506   b  that forms the transition to a forwardmost snowshoe point  578 , is curved upward and is styled with an optional bear claw arch  579  pattern. The ski mode forward portion  506   c  that transitions to a forwardmost ski point  580 , is curved upward and insures that the body  506  stays on top of the snow surface and rides smoothly over small obstacles or choppy ice and snow. The shape of the various portions can be changed and styled in various ways without changing or sacrificing the basic function of the convertible ski shoe  500 . The design can also be made to function without the perimeter tube  576  or aperture tube  546 .  
         [0264]    The smooth bottom convertible ski shoe  500  has two primary modes of operation. FIG. 48 shows the smooth bottom convertible ski shoe  500  assembled in a ski mode. FIG. 56 shows the same parts rearranged and reconfigured into a snowshoe mode. In addition, there are four secondary ski modes, including glide ski, fixed ski, ski with brake stop, and ski without brake stop. Additionally, there are two secondary snowshoe modes, which are with flush teeth and with protruding teeth, as previously described. The binding plate assembly  503  is attached or bound to the foot and remains attached to the foot during a conversion to ski mode from snowshoe mode or vice-versa. The toe portion  518   b  of the binding attachment plate is mounted in the same direction as the toe of the foot. The toe portion  518   b  of the binding plate is inserted in the convertible plug assembly  510  pointed in the direction of the ski mode forward portion  506   c  of the body  506  for all of the primary and secondary ski modes. The toe portion  518   b  of the binding plate  518  is inserted in the convertible plug assembly  510  pointed in the direction of the snowshoe mode forward portion  506   b  of the body  506  for all of the primary and secondary snowshoe modes.  
         [0265]    Referring to FIGS.  61 A- 61 E, the primary snow contact surface  522  of the body  506  makes contact with the surface being traversed. In soft snow or powder, the secondary snow contact surface  524  and tertiary snow contact surface  526  will also make contact with the snow surface. The overall body  506  can be proportioned to have sufficient area to keep the device floating up in soft snow or deep powder while in ski mode or providing sufficient area to prevent sinking in snowshoe mode. The combination of primary snow contact surface  522 , secondary snow contact surface  524 , and tertiary snow contact surface  526  will allow a short ski design to act similarly to a long ski. Current narrow short ski designs are not functional in deep powder conditions because of a lack of sufficient lift surface area.  
         [0266]    Since the secondary snow contact surface  524  is offset from the primary snow contact surface  522 , both surfaces can be nearly flat and parallel with respect to the surface being traversed, while allowing the smooth bottom convertible ski shoe to freely roll from side to side at a roll. The relationship between the primary snow contact surface  522  and tertiary snow contact surface  526  is similar. The tertiary snow contact surface  526  is an optional styling element that nicely blends the bear claw arches  579  into the lines of the ski shoe. In snowshoe mode, the primary snow contact surface  522  will sink into soft snow first. The cathedral shaped profile of the secondary snow contact surface  524  and tertiary snow contact surface  526  and the teeth  552  will then provide lateral stability. The secondary snow contact surface  524  and tertiary snow contact surface  526  will provide enough extra support to keep the user from sinking. The secondary snow contact surface  524  and tertiary snow contact surface  526  are almost parallel with the ground and will tend not to wedge into the snow as a result.  
         [0267]    Referring to FIG. 46, the body  506  is connected to the convertible plug  504  with two coaxial pivot pin assemblies  508 . Rolling motion is imparted by the foot through the pivot pins  562  and into the body  506 . This rolling motion causes either of the inner edges  528  to dig into the snow for directional control similar to existing short or long ski designs. The roll angle is sufficient to allow this rolling motion to occur without interference from the secondary snow contact surface  524  or tertiary snow contact surface  526 . In case of extreme rolling due to a fall or extreme slopes, an outside edge  584  can cause the corresponding inner edge  528  to lift off the snow surface. The inner edges  528  are simply sharp corners of the parent material of the smooth bottom convertible ski shoe body  506 . Molded in metal inserts could be used to improve the cutting action of the edges if more control is desired especially on ice. However, if extreme roll conditions are experienced and the outside edges  584  cause the inner edges  583  to pry off of the surface, a loss of control could result. If the two edges are similar in construction and geometry, then they will both perform similarly, and a surprise loss of control will not be experienced.  
         [0268]    In view of the foregoing, it is recommended that both inner edges  528  and outer edges  584  have optional inserts or have similar geometry and material. The outer edges  584  have been designed to keep them straight and parallel to the inner edges  528  for maintaining a similar or improved edging response for maximum safety. The outer edges  584  are actually slightly sharper to increase the edging force and provide an extra degree of control in the case of an excessive roll angle. Optional intermediate edges  585  (FIG. 64) and  586  (FIG. 75) are primary a styling feature and do not serve to significantly change the edging response. If the inner and outer edges  528  and  584  are improved with optional inserts, there would not be a requirement to do the same for the intermediate edges  585  and  586 . Referring to FIGS. 77 and 78, the clip  569  stows in a clip recess  587  to make a beam outer surface  588  flush and straight. This insures that contact of the left hand smooth bottom convertible ski shoe  500  with the other does not entangle with and tends to straighten the two relative to each other to avoid crossed skis.  
         [0269]    The body  506  can be constructed a number of ways, the preferred one being a two piece hollow design. The shells are preferably made from a tough injection molded plastic, such as a polycarbonate acrylic blend, which has a pleasant translucent look. Injection molded parts minimize the touch labor required to set up each part. An alternate construction would be of long or short fiber reinforcement for maximum strength, stiffness, and damage tolerance at minimal weight. The two halves preferably have a snap fit design where plastic snap elements would permanently lock the two halves together. Once the two halves lock together, they function as an integral closed cell box. Shear bosses ensure that the two halves function as a unit. This manufacturing method would also be consistent with the other parts. Local stiffeners and internal ribs (not shown) are used to internally stiffen the skins of the shells. Local areas of higher stress could be strengthened by an increase in thickness. An alternate method to assemble the halves would be to secure them together with fasteners or screws spaced periodically around the perimeter.  
         [0270]    The body  506  could alternately be constructed as described above, with the snap features replaced with a bond or welding. The body  506  may alternately be constructed as a one piece foam filled or hollow part. The skin material could be made from epoxy-bonded fiberglass, carbon, or a metallic material, such as aluminum. The skins can form a bonded assembly with an internal foam core. The skins can be a wet lay up over a foam core to save weight. An alternate means of manufacture would be to use some form of resin transfer molding or vacuum assist resin transfer molding of resin into a closed cavity mold with dry preform broad goods over an internal mandrel. A hollow design could also be produced using a rotomolding process or a reaction injection molding process.  
         [0271]    Referring to FIGS. 63, 70B, and  71 B, a ski mode toe surface  589  of the body  506  and a snowshoe mode toe surface  590  are shaped not to interfere and contact with corresponding end interface surfaces  591  of the convertible plug  504 . The ski mode toe surface  589  and the snowshoe mode toe surface  590  with their corresponding end interface surfaces  591  of the convertible plug  504  are radiused with the center at the pivot axis  520 , a tight fit will insure that the gap is minimized and foreign objects can not easily get wedged or trapped.  
         [0272]    Referring to FIGS. 77 and 78, the pivot pin assembly  508  is detailed as a solid pin, although many other types of shear pins would work including a quick release pit pin in this application. A simple spring clip (not shown) could be slipped through a small hole transverse to the longitudinal axis of the pivot pin or a self-locking wing nut could be used to retain the pin. A removable pivot pin could be placed in any number of multiple pivot hole positions (not shown) located forward and aft of each other along the longitudinal axis of the ski shoe to customize the braking or gripping response.  
         [0273]    The convertible plug  504  is free to rotate about the pivot axis  520 . The pin height is set to keep the pivot pin assembly  508  clear of the surface being traversed when the body  506  is rolled to either side for cutting in ski mode or walking transverse along inclines in snowshoe mode. The pivot axis  520  is shown roughly at the middle of the convertible plug  504 , so that the convertible plug will rotate and have equal clearance between the end interface surface  591  and the ski mode toe surface  589  and the snowshoe mode toe surface  590 .  
         [0274]    An optional lanyard (not shown) could be used to retain a loose pivot pin assembly  508  or plug rotation limiter pin  534 . This lanyard could be an elastic “bungee cord” that pulls itself back into the pin when not used to prevent a possible entanglement or snagging.  
         [0275]    Referring to FIGS. 66 and 74, the binding attachment plate  518 , while unitary in construction, may be thought of as being comprised of three portions, including a center portion  518   a , the toe portion  518   b , and a heel portion  518   c . The center portion  518   a  extends along the region of constant width. The toe portion extends along the end transition radius to the front tip, and the heel portion  518   b  extends along an end transition radius to the rear tip. If the skier wants to slow down or stop, weight is simply shifted to the heel portion  518   b  of the binding attachment plate  518 . The heel portion  518   b  then will push down into the surface of the snow through the convertible plug assembly  504  and cause the snow to displace downward and to the side. The energy required to displace the snow will cause the skier to slow down and finally stop. In snowshoe mode weight is simply shifted to either the toe portion  518   b  or heel portion  518   c  to cause the convertible plug to rotate and engage the teeth  552  for gripping and traction. The width of the binding attachment plate  518  is wider than the foot to allow a full range of motion of the foot in snowshoe mode. The binding attachment plate  518  and either a ski side  504   c  or a snowshoe side  504   d  of the convertible plug  504  nest together the same way by contact at plug interface surfaces  592  on the binding attachment plate  518 .  
         [0276]    The binding attachment plate  518  can be constructed a number of ways, the preferred one being a one piece injection molding made from a toughened or reinforced plastic. Injection molded parts minimize the touch labor required to set up each part. The reinforcement could be a longer fiber variety for maximum strength, stiffness, and damage tolerance at minimal weight. Although the binding attachment plate  518  is designed as a solid thick plate, once the bindings are selected, binding attach bosses  593   a  and holes  593   b  can be located in which to mount the bindings. Local stiffeners, an outer flange  594   a , ribs  594   b , or boss support flanges  594   c  could be located like designs in previous embodiments to lighten the part and would be used to stiffen the skins of the outer shell  594   d  and deck  516 . The binding attachment plate  518  works in conjunction with the convertible plug  504  to form an effective closed box structure. A closed box structure is naturally the most efficient section for maximum torsional stiffness. Optional binding attach bosses and binding attach holes are not shown, but could be detailed in the deck to receive standard style bindings. The deck and optional outer of the binding attachment plate  518  can support any number and arrangements of strap holes or additional flanges or other features that would be molded into or would extend above the surface of the deck. Various other types of ski, telemark, cross-country, snowshoe, or Rottefella bindings can be mounted to standard mounting holes and inserts located on the surface of the deck. An optional non-skid surface  595  feature not shown on the deck surface would help keep the foot from sliding around.  
         [0277]    Referring to FIGS.  80 - 87 . The binding plate assembly  503  is comprised of several other features that form a locking mechanism with the convertible plug assembly  510 . Although details of the locking assembly are shown, any number of alternate lock details could be substituted to do the same job. A plug attach stud  596   a  is shown integral with the binding attachment plate  518 . This plug attach stud may be more suited to a separate metal piece to insure reliability. To minimize the stresses between the plug attach stud  596   a  and the deck  516 , a generous plug attach stud fillet  596   b  is required. A lock  596   c  is assembled by slipping the sleeve  596   d  on the plug attach stud  596   a . The flare  596   e  covers up the fillet  596   b  and prevents adequate periodic inspection for safety. The optional upper oblong shear block  596   f  has a sleeve hole  596   g  that is then slipped over the sleeve  596   d  of the lock  596   c . The upper oblong shear block  596   f  is installed such that a key  596   h  engages into an anti-rotation keyway  596   i  on the binding attachment plate  518 . This upper oblong shear block  596   f  serves to reduce bending in the plug attach stud  596   a  by transferring shear between the surface  596   j  and the fillet  596   b  and an inner hole surface  596   k.    
         [0278]    Next, a middle oblong lock block  597   a  is fitted over the sleeve  596   d  of the lock  596   c  through a sleeve hole  597   a ′. Optional anti-rotation flats  597   b  are aligned with the anti-rotation flats  596   l  on the sleeve  596   d  of the lock  596   c . These parts could be alternately pinned or bonded into place. The middle oblong lock block  597   a  is released by rotating a lock handle  597   c  from a distal lock keeper  597   d  position to the mesial lock keeper  597   e  position. The design could also be set up to release in the distal lock keeper  597   d  position if desired for clearance or other reasons. The lock is retained at the mesial lock keeper  597   e  or distal lock keeper  597   d  by a spring retention element  597   f . The spring retention element  597   f  is detailed to the bifurcated neck  597   g  with a relief radius  597   h  to prevent high local stresses and cracking. The middle oblong lock block  597   a  is actuated with a large leverage from an offset of an arm  597   i  offset. An arm kink  597   j  is designed for a tight fit along the edge chamfer  597   k . The lock is located in the lock arm recess  597   l  and can swing from lock stop edge  597   m  to lock stop edge  597   m . This lock configuration is called a hidden lock, because the lock is contained in a lock arm recess  597   l  under the binding attachment plate  518 . In the distal lock position, the middle oblong lock block  597   a  is turned 90 degrees out of alignment with the oblong hole  597   o  in the lock plug  597   p  and a lock slot  597   q  in the convertible plug  504 . The binding attachment plate  518 , therefore, cannot pull up away from the convertible plug assembly  510 , as an upper contact surface  597   v  of the middle oblong lock block  597   a  interferes with the contact surface  231  on the lock plug  597   p  or a locking contact surface  597   t  on the binding attachment plate  518 . The middle oblong lock block  597   a  transfers compression between upper and lower contact surfaces  597   r ,  597   u.    
         [0279]    A lower oblong cap block  598   a  is then assembled by aligning a stud receiver hole  598   b  on the sleeve  596   b . Anti-rotation flats  598   c  and  598   d  are aligned and an optional lower block retainer pin  598   e  is inserted through the retainer pin holes  598   f  and  598   g . The lower oblong cap block  598   a  could also be bonded in place. A guide chamfer of the lower oblong cap block  598   a  aids in aligning and guiding the binding plate assembly  503  with the oblong hole  597   o  into the lock plug  597   b  or the lock slot  597   q  in the convertible plug  504 . A contact surface  598   h  transmits compression into the lower contact surface  597   u.    
         [0280]    Referring to FIGS.  69 A- 71 C and  74 - 76 , the convertible plug  504 , while unitary in construction, may be thought of as being comprised of four portions, including a center portion  504   a , an end portion  504   b , a ski side  504   c , and a snowshoe side  504   d . The center portion  504   a  extends along the region of constant width. The end portion  504   b  extends along the end transition radius to the end interface surface  599 . The ski side  504   c  also has a primary ski surface  523  that makes contact with the ground plane  555 . In soft snow or powder, the secondary ski surface  525  will also make contact with the snow surface as described for the body  506 . When the skier wants to ski without braking action or restraint, weight is shifted forward, and the binding attachment plate  518  rotates into the a position in which the primary ski surface  523  and secondary ski surface  525  of the convertible plug  504  align themselves with the primary  522  and secondary surfaces  524  of the body  506 . In this position, the smooth bottom convertible ski shoe  500  offers very little resistance to sliding.  
         [0281]    The snowshoe side  504   d  of the convertible plug  504  has an outer shell  599   a  with teeth  552  formed on the edge. These teeth  552  provide traction and gripping. Although the teeth are integral with the rest of the convertible plug material, an optional metal or other material insert could be used in an injected molded part to make the teeth edges more durable and effective. For cost considerations, however, the integral material approach has merit.  
         [0282]    The convertible plug  504  can be constructed a number of ways, the preferred one being a one piece injection molding made from a toughened or reinforced plastic. Injection molded parts minimize the touch labor required to set up each part. The reinforcement could be a longer fiber variety for maximum strength, stiffness, and damage tolerance at minimal weight. The outer shell  599   a , end interface surface  599 , lateral ribs  599   b , and the pivot hole rib  599   c  would be used to stiffen the primary ski surface  523  and secondary ski surface  525 . The pivot hole rib  599   c  could be better integrated into the lug tooth pad-up  599   d  to stiffen bending loads. The lateral ribs  599   b  and diagonal ribs  599   e  could be simplified if the binding attachment plate  518  worked in conjunction with the convertible plug  504  to form an effective closed box structure.  
         [0283]    The convertible plug assembly  510  includes a lock plug  597   p  (FIG. 72) that is necessary in order to injection mold the part without a washout mandrel or a trapped cavity. The lock plug ears  599   g  help to align the part in the barrels  599   h . The lock plug  597   p  can be aligned properly and bonded into barrels  599   h  and lands  599   i  of a faying surface  2599   j  to the convertible plug  504 . The lock plug  597   p  can also be optionally secured into the barrel  599   h  by installing a retention pin into the retention pin holes  599   k  and  599   l . The optional metal pivot pin doubler  599   m  (FIG. 73) is used as a safely device during tests to insure the pivot pin  562  does not break out of the convertible plug  504 .  
         [0284]    To prevent snow and ice from accumulating in the cavities of the snowshoe side  504   d  of the convertible plug  504 , an optional stiff closed foam insert material (not shown) could be molded or cut to fit snugly into the open cavities between the ribs and the shell of the convertible plug  504  or the binding attachment plate  518  to provide a light weight inexpensive seal. The foam insert could be glued in place to keep it secure.  
         [0285]    It is understood that several modifications, changes and substitutions are intended in the foregoing disclosure and in some instances some features of the invention will be employed without a corresponding use of other features. Accordingly, it is appropriate that the appended claims be construed broadly and in a manner consistent with the scope of the invention.