Abstract:
The novel snowshoe ( 400 ) includes at least one tail extender ( 404 ) to provide variable flotation characteristics and traction bars ( 412 ) that provide improved side slip protection such as when traversing steep terrain. The snowshoe ( 400 ) is thereby especially advantageous for use in back country mountaineering. A three (or more) point attachment mechanism is disclosed for coupling the tail extender ( 404 ) to the flotation plate ( 416 ) of snowshoe ( 400 ) so as to reduce stress on the coupling elements and provide a more secure interface.

Description:
RELATED INFORMATION 
     This application is a continuation of U.S. patent application Ser. No. 08/734,327 filed Oct. 21, 1996 (U.S. Pat. No. 5,921,007) which is a continuation-in-part of co-pending U.S. patent application Ser. No. 08/645,197 filed May 13, 1996 which is a Continuation of U.S. patent application Ser. No. 08/209,383, filed on Mar. 10, 1994 (U.S. Pat. No. 5,531,035), which is a continuation-in-part of U.S. patent application Ser. No. 08/141,853 filed on Oct. 22, 1993 (U.S. Pat. No. 5,469,643) and U.S. patent application Ser. No. 08/194,983 filed on Feb. 10, 1994 (U.S. Pat. No. 5,517,773). 
    
    
     FIELD OF THE INVENTION 
     The present invention relates generally to snowshoeing and, in particular, to a novel snowshoe and binding which provides improved foot stability (especially heel stability), adjustable flotation characteristics, improved side, forward and reverse slip protection, forward tracking guidance and overall stability and lightweight material options. The invention is especially well-suited for back-country mountaineering where side-slip protection and variable flotation characteristics take on greater, if not critical, importance. 
     BACKGROUND OF THE INVENTION 
     According to some historians, the first snowshoes were developed about 6,000 years ago in Central Asia. Snowshoes have been used in North America for many centuries, first by native American peoples and later by trappers, explorers and other European settlers. Traditionally, snowshoes were formed from light oval or teardrop shaped wooden frames strung with thongs made from animal hide. The resulting snowshoe could then be strapped to a person&#39;s foot, i.e., directly or via footgear, so as to enable the person to walk in soft snow without sinking too deeply. 
     Today, snowshoes are most commonly used for recreation and by mountaineers to facilitate winter access to remote back country locations. Although the materials and production techniques have changed, modern snowshoes have much in common with traditional snowshoes developed over the centuries. FIG. 1 illustrates some features of one type of snowshoe  1  in common use today. The general shape of the snowshoe  1  is defined by a tubular perimeter structure  2  which is ordinarily formed from aluminum. The requisite flotation surface area is typically provided by webbing or a platform  3 , formed from animal hide or synthetic materials, which is connected to the tubular perimeter structure  2  via sturdy lacing  4  or rivets. The snowshoe  1  is attached to the wearer&#39;s foot via footgear  5  using a toe strap  6 , and an additional heel strap  7  is usually provided. Often, a hinged metal device or so-called crampon  8  which extends through an opening  9  in platform  3  is provided to improve forward traction on hills or ice. 
     Despite the long evolution of the snowshoe art, current snowshoes are subject to certain limitations. For example, when the snowshoer traverses a steep hill, current snowshoes are highly susceptible to side slippage. Similarly, current snowshoes can slip forwardly or rearwardly when a hill is addressed directly, particularly in icy conditions. In addition to being a source of annoyance, such slipping can be a matter of grave safety concern for the back country mountaineer. Conventional snowshoes do not always provide adequate protection against forward, rearward and side slippage. 
     Another limitation of current snowshoes is that the snowshoes have invariable flotation characteristics relating to the size of the snowshoe. However, the desired flotation characteristics of a snowshoe vary from user-to-user, from application-to-application, and depending on snow conditions or other factors. For example, a larger snowshoe is normally better for a heavier snowshoer, when carrying a heavy pack or when snowshoeing in deep and soft snow. Smaller snowshoes are typically preferred for running or racing (as is becoming increasingly popular). Many avid snowshoeing enthusiasts therefore have more than one pair of snowshoes. This is not a completely satisfactory situation for a number of reasons. First, the expense of acquiring more than one pair of snowshoes is prohibitive for many. In addition, the snowshoer cannot always accurately predict what conditions may be encountered during an outing. Snow conditions can change rapidly, particularly in back-country mountaineering expeditions involving large altitude changes. Moreover, for outings lasting several days, conditions may change due to storms, wind, temperature changes and other weather phenomena. Furthermore, as can be readily appreciated, it is not always convenient to store and carry more than one pair of snowshoes. 
     Current snowshoes as described above are also subject to a certain instability relating to snow compaction. In particular, as the snowshoer places weight on the snowshoe, the platform tends to flex to a concave shape. As a result, snow may be forced towards the snowshoe perimeter rather than providing stable support under the snowshoer&#39;s foot. 
     Additionally, current snowshoes tend to create resistance to the shuffling movement entailed in forward snowshoeing. In this regard, the tubular perimeter and angled orientation of common snowshoe perimeter structures result in snow plowing when the snowshoe is shuffled in a forward direction. Moreover, current snowshoes generally do not facilitate forward tracking, i.e., even on flat ground, current snowshoes can easily drift transversely to the desired direction of travel during shuffling. 
     The snowshoe binding has also presented persistent challenges for snowshoe designers as many desired binding qualities seemingly demand incompatible design features. For example, the binding must be able to securely accommodate a variety of footgear sizes and styles in order to be suitable for general use. However, in order to facilitate proper snowshoeing motion and reduce strain on the snowshoer, the binding must provide excellent lateral foot stability, limit vertical movement of the snowshoer&#39;s footgear, and limit forward or rearward slipping of the footgear as may occur in hilly terrain. In addition, it is highly desirable to provide a binding which can be quickly and easily attached and detached even though the snowshoer&#39;s finger dexterity may be limited due to coldness or handgear. 
     Accordingly, there is a need for an improved snowshoe which addresses the limitations and challenges facing snowshoe designers. 
     SUMMARY OF THE INVENTION 
     The snowshoe of the present invention provides variable flotation characteristics, improved protection against slipping especially side slipping when traversing steep terrain, improved forward tracking guidance and overall stability and reduced weight. In addition, the present invention includes a binding which is easy to construct and use, yet is capable of securely and stably engaging a variety of footgear and footgear sizes. 
     According to one aspect of the present invention, the snowshoe includes a flotation surface and a pair of traction bars mounted on the flotation surface and projecting downwardly from the flotation surface. The flotation surface is preferably formed from one or more sheets of lightweight and rigid or semi-rigid material such as thermal formed plastic. The traction bars, which can be formed as an integral portion of the flotation plate or formed as separate pieces for attachment to the flotation plate, are laterally spaced for stability. In one embodiment, the flotation surface has an opening through which a crampon and a forward portion of the snowshoer&#39;s foot can project, and the traction bars are positioned adjacent to the side edges of the opening. The traction bars extend substantially linearly along the length of the flotation plate and preferably have narrow bottom and frontal profiles. In addition, the traction bars have a length which is at least about equal to the length of the snowshoer&#39;s foot. The traction bars can also include a lower edge having indentations, e.g., teeth, for improved traction. The traction bar indentations are preferably formed with rounded extremities for improved fracture resistance. 
     The traction bars provide a number of advantages relative to conventional snowshoes. First, the traction bars penetrate into the snow during use and thereby afford positive protection against sideslipping. The traction bars therefore provide for greater safety when traversing steep terrain. The traction bars also impart improved torsional rigidity to the flotation plate so that the material requirements of the flotation plate can be reduced and a lighter weight snowshoe can be achieved. Moreover, the crampon can be connected to the traction bars thereby shortening the crampon connection and reducing strain on the connection assembly. The traction bars also penetrate the snow during shuffling movement substantially without plowing and contribute to forward tracking guidance. By providing a toothed lower edge on the traction bars, improved traction and protection against forward or rearward slipping can also be imparted. 
     According to another aspect of the invention, a snowshoe with variable flotation characteristics is provided. The snowshoe comprises a flotation plate and at least one extension member which is detachably coupled to the flotation plate for selectively increasing the snow contact surface area of the snowshoe. Preferably, more than one extension member is provided to allow for a variety of snow contact surface areas. In one embodiment, the extension members comprise tail extenders which can be attached to a rearward portion of the flotation plate to increase the length of the snowshoe. An alignment mechanism can be provided to assist in attachment of the extension members and to insure stable alignment of the extension members during use. For example, the alignment members may comprise a mating coupling between the flotation plate and the extension members. In a preferred embodiment, the flotation plate and extension member are secured together at at least three locations spaced across the width of the snowshoe. Such attachment has been found to maintain a more positive contact between the flotation plate and extension member during use. For ease of extension member connection and disconnection, at least one of the interconnections can be accomplished by way of a sliding or snapping engagement mechanism. One such embodiment employs a spool on one of the flotation plate and extension member for engaging a groove on the other of the flotation plate or extension member. Although a particular embodiment of the variable length snowshoe is described below, it will be appreciated that the variable length concept is applicable to various types of snowshoes. 
     Another aspect of the present invention relates to providing a snowshoe binding with improved lateral foot stability. It has been found that certain snowshoe bindings are susceptible to lateral foot instability during use. In particular, the wearer&#39;s heel may tend to move from side-to-side relative to the snowshoe, particularly when traversing a steep side slope. This problem is addressed in accordance with the present invention by providing a binding including a flexible footwrap attached to a support member which underlies the wearer&#39;s foot, wherein the support member has a length sufficient to underlie a majority of the wearer&#39;s foot. Preferably, the support member is at least about six inches in length and the footwrap is attached to the support member at least adjacent to the front and back ends thereof. This length can be provided via a heel extension which extends beneath the arch of the wearer&#39;s foot to or towards the wearer&#39;s heel. It will be appreciated that the majority of the support surface, which is pivotably connected to the snowshoe, will lie behind the pivot point. The footwrap is secured to the wearer&#39;s footgear by way of one or more straps that extend over the wearer&#39;s footgear and, preferably, around the heel of the footgear. In one embodiment, the strap(s) extends from the footwrap on one side of the footgear and is threaded through a receiving structure mounted on the footwrap on the other side of the footgear. A stopper can be provided on the strap to prevent the strap from becoming unthreaded when the strap is loosened. The strap coupling of the present invention allows for easy engagement and disengagement, even when the user is wearing gloves or mittens or when the user&#39;s finger dexterity is limited due to cold weather or otherwise. Alternatively, a strapless step-in binding, such as used in connection with snowboards, may be employed. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1, as described in the Background of the Invention, illustrates some features of one type of prior art snowshoe; 
     FIG. 2 is a perspective view of a snowshoe constructed in accordance with the present invention; 
     FIG. 3 is a bottom view showing the flotation plate and traction bars of the snowshoe of FIG. 2; 
     FIG. 4 is a side view of the flotation plate and traction bars of the snowshoe of FIG. 2; 
     FIG. 5 is a cut-away front view of the flotation plate, traction bars and crampon of the snowshoe of FIG. 2; 
     FIG. 6 is a bottom view showing the interconnection between the crampon and traction bars of the snowshoe of FIG. 2; 
     FIG. 7 is a side view of the crampon of the snowshoe of FIG. 2; 
     FIG. 8 is a top plan drawing showing the unfolded shape of the foot wrap of the snowshoe of FIG. 2; 
     FIG. 9 is a perspective view of a snowshoe constructed in accordance with an alternative embodiment of the present invention showing attachment of a tail extender; 
     FIG. 10 is a bottom view of the snowshoe of FIG. 9 with an optional second tail extender shown in phantom; 
     FIG. 11 is an elevational plan view of a traction bar where the dashed lines indicate where the traction bar will be bent to allow for attachment to the snowshoe flotation plate; 
     FIG. 12 shows the unfolded shape of the foot wrap of the snowshoe of FIG. 9; 
     FIG. 13 shows the pre-formed shape of the crampon of the snowshoe of FIG. 9; 
     FIG. 14 shows the unfolded shape of the gripping tab of the snowshoe of FIG. 9; 
     FIG. 15 is a side view of the crampon of the snowshoe of FIG. 9; 
     FIG. 16 is a perspective view of a snowshoe constructed in accordance with the present invention showing a binding incorporating a heel stabilizing extension; 
     FIG. 17 is a bottom view of a binding support plate incorporating a heel stabilizing extension in accordance with an embodiment of the present invention; 
     FIG. 18 is a bottom view of a binding support plate incorporating a heel stabilizing extension in accordance with a further embodiment of the present invention; 
     FIG. 19 is a side view showing a motion limiting protrusion constructed in accordance with the present invention; 
     FIGS. 20 and 21 are top and exploded bottom perspective views, respectively, of a snowshoe constructed in accordance with a further embodiment of the present invention; 
     FIG. 22 is a top view of a tail extender for use in connection with the snowshoe of FIGS. 20 and 21; 
     FIG. 23 is a side cross-sectional view of the tail extender of FIG. 22; 
     FIG. 24 is a perspective view of a tail portion of the snowshoe of FIGS. 20 and 21 showing the attachment spool; and 
     FIG. 25 is a perspective view of an alternative binding strap assembly for the snowshoe of FIGS. 20 and 21. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring to FIGS. 2-8, a snowshoe constructed in accordance with the present invention is generally identified by the reference numeral  10 . Generally, the snowshoe  10  comprises a flotation plate  12 , traction bars  14  and  16 , a crampon  18  and a binding  20 . In the illustrated embodiment, the binding is designed for attachment to a snowshoer&#39;s footgear  28 . 
     The flotation plate  12  can be formed from any of various lightweight semi-rigid materials such as various plastics. The illustrated flotation plate  12  is formed from {fraction (3/16)} or ⅛ inch thick thermal formed, high density polyethylene which provides adequate strength and rigidity and allows for simple and inexpensive construction. The overall dimensions of the flotation plate  12  can be varied depending on the weight or skill of the snowshoer, the size of the snowshoer&#39;s footgear  28 , local snow conditions, the load being carried or other factors. In this regard, the snowshoe  10  can be provided, for example, in various lengths (e.g., 22 inches, 26 inches or 30 inches) and widths (e. g., 8 inches or 9 inches) to accommodate a range of conditions. The illustrated flotation plate  12  has a length L 1 , of about 26 inches and a width W 1  of about 8 inches. 
     The shape of the flotation plate  12  is further defined by a number of molded curves and channels and a central cut-out  24 . The cut-out  24  is provided to allow the crampon  18  and a toe section  26  of the snowshoer&#39;s footgear  28  to extend through the flotation plate  12  for improved traction. The illustrated cut-out  24  has a length L 2  of about 8.75 inches and a width of about 5.25 inches. The flotation plate  12  can also be provided with perforations (not shown) to minimize snowshoe weight. 
     In order to facilitate forward shuffling of the snowshoe  10  through snow, the tip portion  30  of the flotation plate  12  adjacent leading edge  32  is curved upwardly. The upward curve begins just forward of the cut-out  24 , about 5 inches from leading edge  32 . The curve defines an approximately 36° angle relative to horizontal such that the forward most point of leading edge  32  is elevated to a height H of about 3.75 inches relative to the base of flotation plate  12 . As will be better understood upon consideration of the description below, the upward curve is actually a compound curve resulting from the blending of the upward tip projection and the overall convex frontal profile of the flotation plate  12  as can be see in FIG.  5 . 
     In the illustrated embodiment, the flotation plate  12  further includes a pair of side channels  34  and  36  and a central channel  38 , each of which extends along a rear portion  40  of the flotation plate  12  to rear edge  42 . The channels are formed as recesses into the underside of flotation plate  12 . The illustrated central channel is about ½-¾ inch wide, ½-¾ inch deep and its front edge  44  is located rearwardly from cut-out  24 . The side channels  34  and  36  are slightly smaller than the central channel  38 , e.g., about ⅜-½ inch wide and ⅜-½ inch deep. During forward travel,, snow passes through the channels  34 ,  36  and  38  and exits at the rear edge  42  of the snowshoe  10  such that the channels  34 ,  36  and  38  enhance forward tracking guidance. These channels  34 ,  36  and  38  also add rigidity to the rear portion  40  of the flotation plate  12 . 
     In an alternative embodiment (not shown), the side channels are eliminated, the traction bars extend further towards the rear edge of the flotation plate and the central channel is enlarged. In addition, the central channel has a tapered profile which extends upwardly relative to the flotation plate such that the snowshoer&#39;s footgear is urged forwardly due to the taper inclination. 
     As can be most clearly seen in FIG. 5, the flotation plate  12  has a convex frontal profile such that the side edges  46  are positioned lower than a central portion  48  of the flotation plate  12 . In the illustrated embodiment, this profile is defined by a radius of curvature of about 12 inches. When the snowshoer places weight on the snowshoe  10  thereby forcing the flotation plate  12  downwardly into the snow, the convex frontal profile causes snow to gather or move towards the center of the flotation plate  12  so that a stable snow platform is provided beneath the snowshoer&#39;s foot. In addition, as the snowshoer shuffles forwardly, the convex flotation plate  12  forms a snow ridge which further assists in forward tracking guidance. 
     The snowshoe  10  further includes a pair of traction bars  14  and  16  which project downwardly from flotation plate  12 . The traction bars  14  and  16  can be molded into flotation plate  12  or formed separately for attachment to flotation plate  12 . The illustrated traction bars  14  and  16  are formed from {fraction (3/32)} inch thick aluminum or other metal and are attached to flotation plate  12  via rivets, screws or other fasteners extending through traction bar flanges  54  and  56  into flotation plate  12 . The traction bars  14  and  16  thereby have narrow frontal and bottom profiles which facilitate snow penetration. The angle between each of the flanges  54  and  56  and the corresponding downward projections  58  and  60  of traction bars  14  and  16  is formed such that the projections  58  and  60  extend substantially vertically downward when the flanges  54  and  56  are attached to the convex lower surface of flotation plate  12 . 
     The traction bars  14  and  16  preferably have a length L 3  which is at least about as great as the length of the snowshoer&#39;s footgear  28 . In this regard, the illustrated traction bars  14  and  16  are about 12 inches long and are positioned such that the front edges  62  and  64  thereof are about ½ inch forward from cut-out  24 . The traction bars extend substantially linearly from the front edges  62  and  64  to the rear edges  66  and  68  thereof and are oriented parallel to the direction of forward travel so that substantially no snow plowing occurs during shuffling. In addition, the front edges  62  and  64  in the illustrated embodiment are beveled to further facilitate snow penetration and to allow the traction bars  14  and  16  to smoothly ride up over obstructions. 
     The depth of the downward projections  58  and  60  is selected such that the traction bars  14  and  16  provide protection against side slipping of the snowshoe  10  and also allow for extension of the crampon  18  below the traction bars  14  and  16  for improved forward traction on hills or ice or braking when descending same. Furthermore, the depth of the traction bars  14  and  16  is preferably about equal to the depth of the crampon claws when the crampon  18  is in a level orientation. The illustrated traction bars  14  and  16  extend downwardly about {fraction (9/10)} inch from flotation plate  12 . If desired, the traction bars  14  and  16  can be serrated for additional traction. In addition to protecting against side slipping, it will be appreciated that the illustrated traction bars  14  and  16  further enhance forward tracking guidance and impart longitudinal torsional rigidity to the snowshoe  10  and allow the use of somewhat flexible materials in the flotation plate  12 . 
     As shown most clearly in FIGS. 5-6, the traction bars  14  and  16  are spaced across the width of the snowshoe  10 . Preferably, the traction bars  14  and  16  are spaced by a distance at least about as great as the width of the snowshoer&#39;s footgear  28 . In the illustrated embodiment, the traction bars  14  and  16  are positioned adjacent the sides of cut-out  24  with the flanges  54  and  56  projecting outwardly. This positioning allows the crampon  18  to be attached to the traction bars  14  and  16  such that the crampon connection is short and stress on the connection is minimal as it is substantially totally in shear. The illustrated crampon  18  is connected directly to the traction bars  14  and  16  using pins  88  which allow for pivoting of the crampon  18  with the snowshoer&#39;s footgear  28 . 
     The crampon  18 , which can be formed from a number of materials, such as plate steel or aluminum, includes a number of front claws  70  at its front edge  72  and a number of rear claws  74  at its rear edge  76  for traction. The front claws  70  and rear claws  76  each define an obtuse angle, e.g., approximately 95°, relative to the crampon base for improved forward and rearward traction. In addition, the crampon includes a widened portion  78  provided with downwardly projecting wings  80  for attachment to the traction bars  14  and  16 . The attachment pins  88  are positioned on snowshoe  10  such that more of the snowshoe weight is located rearwardly of the pins  88  so that the snowshoe tip portions  30  naturally rotate upwardly. To reduce weight, perforations  82  can be formed in crampon  18 . Furthermore, in order to minimize icing of the crampon  18 , the crampon  18  can be covered with a plastic laminate  84 . The laminate  84  can be attached to the crampon base, for example, via rivets inserted through holes  86 . If desired, a flexible strap  51  (shown in phantom in FIG. 6) may be used to interconnect the crampon  18  to flotation plate  12  so as to limit the pivoting range of the crampon  18 . 
     The snowshoer&#39;s footgear  28  is attached to the snowshoe  10  by binding  20 . The illustrated binding  20  includes a toe strap  90  which extends over a toe section  26  of footgear  28 , an instep strap  92  which extends over an instep section  108  of footgear  28 , a heel strap  94  which extends around heel section  95  of footgear  28  and foot wrap  96  which wraps about portions of footgear  28 . Each of the straps  90 ,  92  and  94  is provided with an adjustable glide buckle  98  formed from substantially rigid plastic to allow for convenient and quick tightening of the straps  90 ,  92  and  94  by simply pulling on the strap ends. The foot wrap  96 , which is preferably formed from a strong, flexible water repellent material, is attached to the crampon  18  using fasteners such as rivets or stitching, which can be the same fasteners used to attach the material  84  to the crampon  18 . In the illustrated embodiment, the foot wrap is formed from vinyl coated polyester to provide the desired strength, flexibility and waterproof properties and resistance to cold cracking. 
     FIG. 8 shows a top plan view of the unfolded foot wrap  96 . The foot wrap  96  includes a base portion  100  for attachment to the crampon  18 , right  102  and left  104  side portions which wrap around the footgear  28  from the ball section  106  to the instep section  108  thereof, and a toe flap portion  110  which extends around the front edge  112  and over the toe section  26  of the footgear  28 . In addition, the foot wrap  96  includes toe wings  116 , instep wings  118  and heel wings  120  for attachment to the respective toe strap  90 , instep strap  92  and heel strap  94 . The wings  116 ,  118  and  120  on one side of foot wrap  96  are attached to the straps  90 ,  92  and  94  by threading the wings  116 ,  118  and  120  through one side of the buckles  98 , doubling the wings  116 ,  118  and  120  over on themselves, and stitching or otherwise attaching the wings  116 ,  118  and  120  to themselves or adjacent portions of the foot wrap  96 . The straps  90 ,  92 , and  94  are then threaded through the other side of the buckles  98  to complete the attachment. On the opposite side of foot wrap  96 , the wings  116 ,  118  and  120  can be connected directly to the straps  90 ,  92  and  94 . 
     The toe flap portion  110  is widened and includes an opening  122  at the area corresponding to the front edge  112  of footgear  28 . This allows the toe flap portion  110  to flare around the front edge  112  of footgear  28  so as to securely engage the same and enhance both lateral and longitudinal stability. The toe flap portion  110  is further secured by threading the toe strap  90  through slits  124  in toe flap portion  110 . 
     The illustrated binding  20  thus provides excellent lateral foot stability and securely limits both longitudinal and vertical footgear movement. In addition, the binding  20  accommodates footgear  28  of various sizes and styles and is easily and quickly attached to or detached from footgear  28 . The binding  20  is also suitable for use on either the left or the right foot, thereby allowing for interchange ability of the snowshoe  10 . 
     Referring to FIGS. 9-15, an alternative embodiment of the snowshoe  200  of the present invention incorporating additional features is illustrated. Generally, the snowshoe  200  includes: a flotation plate  202  with detachable tail extenders  204  and  206 ; a binding  208  with novel gripping tabs  210 ; toothed traction bars  212 ; a de-icing crampon  214 ; and detachable brakes  216 . 
     The flotation plate  202  can be formed from a semi-rigid material, such as plastic, and is generally shaped as described above in connection with the embodiment of FIGS. 2-8. However, the flotation plate  202  includes extended ribs  238  on front and rear portions thereof (as well as across the entire length of the tail extenders  204  and  206 ) for enhanced torsional rigidity, thereby allowing for a thinner and lighter flotation plate  202  than would otherwise be possible. Particular benefits are achieved by extending each of the ribs  238  past the front  239  and rear  240  ends of the traction bars  212  where large torsional forces are exerted. The ribs  238  are preferably positioned adjacent to the traction bars  212 . 
     The snowshoe  200  allows the snowshoer to vary the snowshoe flotation characteristics as may be desired. This can be accomplished by attaching extenders to vary the snowshoe length and, hence, the snow contact surface area. The illustrated snowshoe  200  is provided with two different lengths of tail extenders  204  and  206  which can be selectively attached to a rear portion of flotation plate  202 . For example, the flotation plate can be about 22 inches long and the tail extenders  204  and  206  can provide for a total snowshoe length of 26 inches and 30 inches, respectively. These three lengths accommodate a great variety of conditions and applications. 
     Any suitable means may be utilized for attaching the tail extenders  204  and  206  to the flotation plate  202 . However, it will be appreciated that the resulting connection must be strong enough to withstand the pressures exerted thereon in use and should allow for easy attachment and removal, preferably without the need to remove hand gear. As shown, the tail extenders  204  and  206  are removably attachable to the flotation plate  202  via a conventional nut and bolt  218  arrangement. The same fasteners which form the rearward most connection between the traction bars  212  and the flotation plate  202  can be used to attach the tail extenders  204  and  206  for increased strength. To further facilitate attachment/detachment, a mechanism for assisting in alignment of the flotation plate  202  and tail extenders  204  and  206  can be provided. For example, appropriately positioned mating members, e.g., tongue and groove or abutting shoulders, can be formed on opposing surfaces of the flotation plate  202  and tail extenders  204  and  206  to ensure proper registration. In the illustrated embodiment, the mating ribs  238  of the flotation plate  202  and tail extenders  204  and  206 , respectively, assist in such alignment and further serve to maintain alignment during use. 
     The snowshoe  200  also includes detachable brakes  216  which work in cooperation with traction bars  212  to provide improved traction and resistance to forward and rearward sliding. The brakes  216  are formed from two plates  220  extending downwardly from the flotation plate  202  adjacent to the traction bars  212 . The plates  220 , which may be formed from aluminum, steel or other substantially rigid material, extend from the flotation plate slightly less distance than the traction bars  212 , about ⅜″, and can be oriented at about a 45° angle relative to the traction bars  212 . In the illustrated embodiment, a space of about ¾ inch is provided between the two plates  220  and between each of the plates  220  and the adjacent traction bar  212 . 
     The resulting “v” configuration of the brakes  216  is preferably oriented such that the widened end of the “v” is closest to the rear of the snowshoe. In this manner, a braking force is exerted during forward sliding due to constricted snow flow between the plates  220  and traction bars  216  and during rearward sliding due to constricted snow flow between the plates  220 . The plates  220  are detachably connected to the flotation plate  202  via conventional nut and bolt  222  assemblies extending through flotation plate  202  and the flanges  224  of plates  220 . 
     The construction of the traction bars  212  is generally similar to that of the traction bars described above in connection with FIGS. 2-8. However, the illustrated traction bars  212  are further provided with teeth  226  formed on the lower edges  228  thereof. The teeth  226  provide enhanced traction on icy surfaces and further assist in preventing undesired forward or rearward slipping. The illustrated teeth  226  are formed with curved extremities for improved fracture resistance. In particular, the illustrated teeth are formed with a radius of curvature R 1 , of about ⅛ inch defining the lower extremities and a radius of curvature, R 2  of about {fraction (1/16)} inch defining the upper extremities. Although other curvatures may be used, the illustrated geometry has been found to provide a good combination of traction and fracture resistance. In addition, in the illustrated embodiment, the tooth pattern is interrupted at the point of attachment  230  of the crampon  214  to the traction bars  212 , where fracturing stresses are greatest, to further guard against fracture. The attachment flanges  268  of the traction bars  212  can be scalloped to further reduce weight. 
     The crampon  214  alleviates ice build-up problems associated with certain known crampon devices. The crampon  214  includes a rigid substrate  232 , which may be formed from steel or other suitably strong material, constructed generally as is described above in connection with the embodiment of FIGS. 2-8, and a flexible diaphragm  234  attached to the substrate  232 . The illustrated crampon has a number of forwardly angled claws  237  and rearwardly angled claws  239 . Binding  208  is attached to the upper surface of substrate  232 . 
     The substrate  232  includes a relatively large aperture  236 . The aperture  236  reduces the total weight of the crampon  214  and also cooperates with the diaphragm  234  to pop-out any accumulated ice on the crampon  214  during use. Specifically, during use, the diaphragm  234  flexes into and out of the aperture  236  as a natural result of the snowshoer&#39;s striding motion thereby preventing ice build-up. The aperture&#39;s length, L, is preferably at least one inch and width, W, is preferably at least two inches. The dimensions of the illustrated aperture are at least about: L=2 inches; W=3 inches. 
     A protrusion  300  for limiting the range of pivotal motion of the crampon  214  is shown in FIG.  19 . The protrusion  300 , which can be formed by a pin, rivet or the like extending from either or both of the traction bars  212 , is positioned so as to contact pivot arm  302  of substrate  232  when crampon  214  reaches a selected limit angle, A, (shown in phantom) thereby preventing further rotation. The angle A is preferably between 60° and 120° and, in the illustrated embodiment, is between about 70° and 80°. 
     An alternative form of the binding  208  is also shown in connection with the embodiment of FIGS. 9-15 (shown in FIG. 12 without straps). The binding  208 , like the binding described above in connection with the embodiment of FIGS. 2-8, can advantageously be formed in a unitary construction from a sheet of heavy weight vinyl coated nylon. However, the binding  208  is constructed in an open-toe style and includes three straps  242  distributed over the toe-to-ball regions of the snowshoer&#39;s foot. As discussed above, the straps  242  can be secured by conventional glide buckles  244  formed from substantially rigid plastic, wherein the straps are tightened by pulling on strap ends  246  and loosened by lifting buckle ends  248 . The binding  208  further includes a heel strap  250  which is preferably secured by a conventional snap buckle  252  for convenient entry and exit. 
     It has been found that it is sometimes difficult to manipulate the glide buckles  244 , and particularly to lift buckle ends  248  to loosen the straps  242 , when the snowshoer is wearing hand gear, the snowshoer&#39;s fingers are cold, or the snowshoer&#39;s finger dexterity is otherwise limited. This difficulty is alleviated in accordance with the present invention by providing gripping tabs  210  (FIGS. 9 and 14) attached to the buckle ends  248  via an aperture provided therein. The gripping tabs  210  can be formed in a unitary construction from a sheet of the same flexible, durable, tear resistant material used in constructing the binding  208  and crampon diaphragm  234 . As shown in FIG. 14, gripping tab  210  includes a first widened portion  254 , a second widened portion  256  and a narrowed portion  258  positioned therebetween. Each of the widened portions  254  and  256  is tapered towards an outer end  260  thereof and can further be provided with an outwardly extending tongue  262  to assist in threading as will be understood from the following description. 
     A gripping tab  210  is attached to a buckle  244  by threading the first widened portion  254  through the aperture in buckle end  248 , wrapping the tab  210  about the buckle end  248  and pulling the second widened portion  256  through an opening  264  in the first widened portion  254  so that the narrowed portion  258  is seated in the opening  264 . In this regard, the narrowed portion serves to lock the tab  210  in place. The opening  264  may be elongated as shown to facilitate threading of the second widened portion  256  therethrough. Additionally, a second opening  266  may be provided in the second widened portion  256  to facilitate gripping. It will be appreciated that the tab  210  is useful in a variety of hand operated adjustment mechanisms, such as zippers, other than the snowshoe strap buckle application shown. 
     Referring to FIG. 16, a perspective view of a binding  304  designed for improved foot stability is shown. The binding  304  comprises a binding support  307 , including crampon portion  306 , which can generally be constructed as described above, and heel stabilizing extension  308 , and a footwrap assembly  310 . The extension  308 , which can be integral with the crampon portion  306  or formed separately for attachment to the crampon portion  306 , extends rearwardly from the crampon portion beneath the arch  312  towards the heel  314  of the wearer&#39;s foot  316 . The footwrap assembly  310  is generally constructed as described above, but is lengthened to correspond to the stabilizing extension  308 . The illustrated binding  304  thus provides for enhanced foot stability, i.e. reduced side-to-side movement of the wearer&#39;s heel  314  during use. 
     FIG. 17 shows a bottom view of the crampon portion  306 , heel extension  308  and a flotation plate  318  constructed in accordance with an embodiment of the present invention. Although omitted for illustration purposes, a flexible laminate such as discussed above is preferably provided across the extent of the crampon portion  306  and heel extension  308 . The laminate is attached by rivets or the like attached via holes  330 . The illustrated crampon portion  306  and heel extension  308  are integrally formed from a single plate of rigid material such as aluminum, steel or the like. The heel extension  308  is provided with a central opening  320  to reduce material requirements and weight, and further to allow for deicing due to flexing of the superimposed laminate (not shown). 
     If desired, the heel extension can overlie the flotation plate  318 . However, it has been found that such a design can result in distracting noise and unnecessary binding/flotation plate contact. Thus, in the illustrated embodiment, opening  322  is formed in flotation plate  318  to correspond to the shape of extension  308 . Preferably, rear edge  324  of opening  322  is disposed in close proximity to rear edge  326  of extension  308  so that the wearer&#39;s heel  314  abuts against flotation plate  318  during use and does not extend through opening  322 . 
     For enhanced stability, the binding support  307  preferably underlies a majority of the snowshoer&#39;s foot  316 . In particular, the support  307  preferably extends beneath the arch  312  of the wearer&#39;s foot  316  to the wearer&#39;s heel  314 . Thus, the length L 3  of support  307  is preferably at least six inches and, in the illustrated embodiment, is about 8.75 inches. In addition, the heel extension  308  extends rearwardly from traction teeth  309  a distance, d, which is preferably at least about two inches and, in the illustrated embodiment is about 3.75 inches. The support  307  is further disposed relative to pivot axis  311  so that most of the support&#39;s length is positioned rearwardly of axis  311  and, preferably, so that at least about ⅔ of the support&#39;s length is positioned rearwardly of axis  311 . 
     FIG. 18 shows an alternative embodiment of the crampon portion  306 , extension  308  and flotation plate  318  which accommodates small feet. During use, it is important that the wearer&#39;s foot does not extend through opening  322 . As shown in FIG. 18, this can be ensured by providing extension  308  in the form of two elongated members  328 . In this manner, opening  322  can be shaped so that flotation plate  318  extends forwardly between the elongated members  328  to provide heel support for shorter boots. In the illustrated embodiment, a cross-member  331  is provided between elongated members  328  for improved strength. 
     FIGS. 20-24 show a snowshoe  400  constructed in accordance with a further alternative embodiment of the invention. The snowshoe  400  is similar in many respects to the snowshoes described above, but includes a number of additional or modified features as will be described below. 
     The illustrated snowshoe  400  includes a three-point attachment mechanism  402  that works in conjunction with a tongue and groove connection  403  to provide superior performance and allow for easy attachment and detachment of any one of the tail extenders  404 . When the snowshoe  400  is used in a walking or shuffling mode, the tail extender  404  tends to impact the snow first with each step or to bear a disproportionate share of the load as weight is shifted from one foot to the other. If only one or two attachment points are utilized in connecting the tail extender  404 , then loading of the tail extender  404  can cause the extender  404  to tend to pivot about an axis of the attachment point(s), thereby placing additional stress on the connection. 
     The illustrated embodiment employs at least three attachment points, for example, two side attachment points  406  and  408  and a center attachment point  410 , arranged in a non-linear fashion, i.e., arranged so as to define a triangular connection region. In this manner, the establishment of a pivot axis extending through all of the attachment points  406 ,  408  and  410  is avoided and the torsional rigidity of the attachment mechanism is enhanced. In the illustrated embodiment, the side attachment points  406  and  408  are located at the rearward ends of the traction bars  412  and  414 . The center attachment point  410  is located at the rearward tip of the flotation plate  416  of snowshoe  400 . 
     Each of the side attachment points  406  and  408  is defined by a spool and slot engagement device for sliding engagement and disengagement. Each of the spool and slot engagement devices includes a spool element  418  (FIG. 24) mounted on one of the flotation plate  416  and tail extender  404  for slidingly engaging a slot  428  on the other of the flotation plate  416  and tail extender  404 . In the illustrated embodiment, the spool elements  418  extend upwardly from the tail section of flotation plate  416  and are mounted on flanges  422  of the respective traction bars  412  and  414  by way of a bolt, rivet or the like extending through the floatation plate  416 . Each spool element  418  includes a base flange  422  and an upper flange  424  separated by an axle  426  so as to define a space between the flanges  424  and  426  for securely receiving the tail extender  404 . The spool elements  418  engage slots  428  formed on a forward portion of the tail extender  404 . Each of the slots  428  includes a widened forward portion  430 FIG. 22) that is dimensioned to receive the upper flange  424  of the spool element, and a rearward portion  432  (FIG. 22) that is dimensioned to receive the axle  426  of the spool element  418  but is narrower than the upper flange  424 . 
     The center attachment point  410  is defined by a hand clamp  434 . The hand clamp  434  includes a threaded bolt  436  inset into mounting flange  438 . Preferably, a suitable mechanism is provided to prevent rotation of the bolt  436  relative to the flange  438 . In the illustrated embodiment, a pin (not shown) extending through the bolt  436  and into a slot formed in the flange  438  is provided for this purpose. The mounting flange  438 , which is an integrally molded portion of the tail extender  404  in the illustrated embodiment, defines a lip surface  440  and a shoulder surface  442 . When the tail extender  404  is coupled to the flotation plate  416 , the trailing edge of the plate  416  is progressively received over the lip surface  440  until the plate  416  abuts or substantially abuts against the shoulder surface  442 . Concurrently, the bolt  436  is received within a slot  444  formed on the trailing edge of plate  416 . The illustrated shoulder surface  442  is curved from side-to-side to substantially match the shape of the trailing edge of the plate  416 . Once the plate  416  and tail extender  404  are thereby properly engaged, a nut  446  is hand threaded downwardly on bolt  436  so that the plate  416  is captured between the lip surface  440  and the nut  446 , thereby securing the tail extender  404 . In this regard, the flange  447  of nut  446  mates with a corresponding recess formed on plate  416  for secure coupling. 
     The coupling of the tail extender  404  to the flotation plate  416  in the illustrated embodiment also involves the tongue and groove connection  403 . The tongue and groove connection  403  operates by engagement of the tongue flange  448  of tail extender  404  within the opening  450  formed in plate  416 . The tongue flange  448 , which can be molded as an integral portion of the tail extender  404 , operates in a manner analogous to the mounting flange  438  described previously. In particular, as the plate  416  and tail extender  404  are coupled, a portion of the plate  416  (i.e., the front edge of opening  450 ) is received over lip surface  452  of tongue flange  448  until the plate portion abuts or substantially abuts against shoulder surface  454  of tongue flange  448 . It will thus be appreciated that the lip surface  452  bears against the underside of plate  416  to maintain the plate  416  and tail extender  404  in a close abutting relationship. 
     To summarize, the coupling of the tail extender  404  to the flotation plate  416  is accomplished as follows. Initially, the tail extender  404  is positioned over the flotation plate  416  so that the upper flanges  424  of the spool elements  418  are received within the widened portions  430  of the slots  428  and the tongue flange  448  of the tail extender  404  is received within opening  450  of plate  416 . The tail extender  404  is then moved forwardly relative to plate  416  so that axles  426  are received within the narrowed portions  432  of slots  428  of the tail extender  404  and bolt  436  is received within slot  444  of plate  416  until plate  416  is disposed adjacent to shoulder surfaces  442  and  454 . The tail extender  404  is then clamped in place using nut  446 . The coupling thus formed reduces stress on the attachment points and maintains a closely abutting relationship across the width of the snowshoe  400  such that snow is substantially prevented from penetrating between the tail extender  404  and the plate  416 . 
     The illustrated snowshoe  400  also shows an alternative configuration and construction of the binding and binding crampon interface. The crampon  456  includes a base plate  458  that is generally constructed in accordance with the description of the embodiments discussed above. However, the footwrap  460  is provided with a transverse slit  462  to receive the tail portion  464  of the crampon  456  such that the footwrap  460  is disposed beneath the base plate  458  only in the area of the tail portion  464 . The footwrap  460  thus cushions the interface between the tail portion  464  and the plate  416  to reduce or substantially prevent wear and distracting contact noise. Relatedly, the alignment of the attachment rivets  466  with openings  468  in plate  416  can be seen in FIG.  21 . The illustrated footwrap  460  includes rounded longitudinal side openings  465  for securely accommodating footgear of various sizes and styles. 
     As shown in FIG. 20, the snowshoe  400  includes a number of strap mechanisms that can be easily operated, even when wearing mittens on gloves. The illustrated embodiment includes three over-the-foot strap mechanisms and one around the heel strap mechanism. Each of the mechanisms includes a flexible and somewhat elastic strap  470 , formed from plastic, rubber or the like (for example, injection molded urethane), and a strap receiver element  472 . Each strap  470  includes a number of sizing apertures  473 , a retainer clip  475  and a removable nub  474  that can be inserted into any of the apertures  473 . Each receiver element  472  includes a threading slot  476  and a finger  478 . The straps  470  are attached to one side of the footwrap  460  using rivets or the like. The receiver elements  472  are attached to the opposite side of the footwrap  460  by forming tongue portions  480  in the footwrap  460 , threading the tongue portions  480  through the slots  476  of the receiver elements  472 , doubling the tongue portions  480  back over the footwrap  460  and then riveting or otherwise attaching the tongue portions  480  to the footwrap  460 . 
     To prepare the strap mechanisms for use, the user threads the strap end through the slot  476  and then inserts the nub  474  into one of the apertures  473  of the threaded strap portion. Thereafter, the nub  474  prevents complete unthreading of the strap  470  thereby simplifying use of the binding. To use the binding, the user inserts his or her footgear inside of the footwrap  460  and the straps  470 . The user then grips the threaded strap portion and pulls the footwrap  460  tight about the footgear. The footwrap  460  is secured by inserting the finger  478  through one of the apertures  473  and inserting the remaining threaded strap portion into the clip  475 . The process is reversed to release the binding. 
     FIG. 25 shows an alternative binding strap assembly  500 . The assembly  500  includes a conventional, single bar slider buckle  502  attached to one side of the footwrap  460  and a strap receiver element  472 , as described above, attached to the other side of the footwrap  460 . The buckle  502  and element  472  can be attached to the footwrap  460  by way of an adhesive, by heat fusion, by RF welding, by using rivets or the like, or by any other suitable method. A flexible strap  504  extends through the element  472 , across the wearer&#39;s foot and through the buckle  502 . The strap  504  includes a molded stop  506  that substantially prevents the strap end from slipping through the element  472  and thereby becoming unthreaded. 
     In operation, the wearer can use the buckle  502  to make a one-time or periodic adjustment to the strap  504  so as to allow for insertion of the wearer&#39;s footgear into the binding with the stop  506  positioned against element  472 . Any excess strap portion pulled through the buckle can then be cut-off or secured to the binding to minimize distraction during use. The assembly  500  is then tightened by grasping the stop  506 , pulling the flexible strap  504  through the element  472  until the desired tightness is achieved, and then inserting the finger  478  of element  472  through an opening in strap  504  to secure the strap  504 . The elasticity of the strap  504 , in combination with the binding geometry and strap pressure, effectively secures the strap  504  in this configuration. Once the strap  504  has been customized for a particular wearer by adjusting the buckle  502 , the assembly can be operated by simply pulling on the stop  506 . Moreover, since the strap  504  is not attached to the footwrap  460 , replacement straps can be readily installed in the event of strap damage or wear. 
     FIGS. 20-21 show additional features of this embodiment of the snowshoe  400 . Specifically, the snowshoe  400  is optionally provided with three molded brakes  482  oriented substantially perpendicular to the traction bars  412 . The brakes  482  extend downwardly from the flotation plate  416  a distance slightly less than that of the traction bars  412  and have a narrow bottom profile to penetrate snow and provide a braking force against forward and rearward sliding. Also shown are a number of wear lugs  484  on the trailing edge to extend snowshoe life. The lugs are positioned and angled to accommodate the mounting flange  438  of the tail extender  404 . Similar lugs can be provided on the tail extender  404 . 
     The bottom surface of the flotation plate  416  and/or the tail extender  404  can be provided with a roughened texture, i.e., via molding or sandblasting, to impart improved frictional characteristics. Finally, FIG. 20 also shows ridges  486  (in phantom) that extend from the bottom of plate  416  to provide enhanced rigidity in the toe section of flotation plate  416  and optional openings  488  that provide advantageous hanging and carrying options. 
     While various embodiments of the present invention have been described in detail, it is apparent that further modifications and adaptations of the invention will occur to those skilled in the art. However, it is to be expressly understood that such modifications and adaptations are within the spirit and scope of the present invention.