Abstract:
A ski vehicle including (a) a seat; (b) a steering mechanism for steering the ski vehicle; (c) a frame; (d) a forward ski member attached to the steering mechanism; (e) a rear ski member; (f) pivotal attachments for pivotally attaching the rear ski member to the frame at longitudinally spaced locations on the rear ski member to permit the rear ski member to flex between the spaced locations; and (g) a footrest for supporting the feet of a user, footrest extending on each side of the frame and being disposed between the seat and the rear ski member.

Description:
FIELD OF INVENTION 
     This invention relates to a snow-type bike sometimes known as a ski bob or snowscoot. 
     Snow-type bikes have become popular with snow sport enthusiasts, and a known bike, more particularly a ski bob, is shown in  FIG. 1 . This known snow-type bike has a frame  1  formed of a crossbar  2  to which is secured a seat pillar  3  and a handlebar headset  4 . Pivotally mounted in the headset is a handlebar column  5 , the lower end of which is pivotally mounted in the headset and the upper end of the column  5  is secured to a pair of user-operable handlebars  6 . The handlebars are connected through the column  5  in the headset  4  to a column  7  that is connected via a suspension unit  8  to a forward ski  9 . The pillar  3  is attached to a seat saddle  10  and the saddle is attached by a strut  11  to a rearward end of a rear ski  12  through a suspension unit  14 , the forward end of the rear ski  12  being attached by a support member  13  to the headset. The terms “forward” and “rear” used herein refer to directions in use, i.e. leading and trailing. Such a known ski bob is ridden by a user who wears a pair of foot skis  15  so as to stabilise the user. Thus, in use, the ski bob is ridden and steered by a user via the forward ski  9  and, of necessity, has their feet on the snow through the intermediary of the foot skis for stability. 
     BACKGROUND OF INVENTION 
     A further form of snow-type bike, which is known as a snowscoot, is shown in  FIG. 2 . In this form of device, there is an inverted Y-shaped frame  20  connected to a headset  24  which pivotally locates a column  25  supporting a pair of handlebars  26 . The lower end of the column  25  is connected to a pair of forks  27  with a lower end of the forks being connected to a forward ski  29 . The frame  20  has a frame member  21  laterally centrally secured to a forward end of a rear ski  30  and another frame member  22  laterally centrally connected toward a rearward end of the rear ski  30 . The rear ski  30  supports a platform  31  having an upturned rear end and at a forward end is located a strap  32  for securing a user&#39;s feet, in use located one on each side of the frame member  22 . In use of the device of  FIG. 2 , a user stands with both feet on the rear ski  30  and steers the device by the handlebars  26 . 
     It is known that users of BMX bikes like to jump over obstacles and to perform freestyle movements of the bikes and of themselves when in mid-air, and a similar desire exists with snow enthusiasts. Neither of the forementioned devices are able to permit such freestyle use to the level and style found in BMX-ing. In the former device of  FIG. 1 , a user, of necessity, has to use a pair of foot skis because the rear ski  12  is too narrow to support a user, and in the snowscoot of  FIG. 2  a user&#39;s feet are secured to the rear ski which may cause a user injury in a crash. Furthermore, the snowscoot of  FIG. 2  does not have a seat. 
     SUMMARY OF INVENTION 
     U.S. Pat. No. 4,097,055, FR-A-2 521 937 and U.S. Pat. No. 3,870,330 disclose a snow-type bike having a frame supporting a seat for a user and located beneath the seat is a rear ski member. A forward ski member is attached to a handlebar steering member. Footrests extend on each side of the frame at a location between the seat and the plane of the rear ski member. However, in such prior art arrangements the rear ski member is fixedly secured to the frame and, as a result, not only are such snow-type bikes uncomfortable but also the rear ski member tends to fracture in use. 
     The present invention seeks to at least partially mitigate the foregoing disadvantages. 
     According to a first aspect of this invention there is provided a snow-type bike for use in snow comprising frame means supporting seat means for a user and steering means, said frame means having a longitudinal axis, a rear ski member attached to said frame means, a forward ski member attached to said steering means, the attachment of said rear and forward ski members being on said longitudinal axis and the attachment of the frame means to the rear ski member being at longitudinally spaced locations of the frame means, and footrest means extending on each side of the frame means at a location between said seat means and the plane of said rear ski member, characterised by means being provided for permitting the rear ski member to flex between said spaced locations. 
     Preferably, footrest means is fixedly located on said frame means or on said rear ski member. 
     Preferably, the forward and rear ski members have a width two or more times, preferably four times, the width of a normal recreation ski. 
     Conveniently, the front and rear ski members have the same width. 
     Preferably, said frame means comprises first and second frame members each joined at a respective first end thereof to a headset member and joined at a second, opposed end thereof to a third frame member, said third frame member being located substantially parallel to said rear ski member, said third frame member carrying said footrest means. 
     Preferably, the footrest means comprise a pair of footrests extending one on each side of said frame means. 
     Conveniently, the vicinity of the juxta position of the first and third frame members and the second and third frame embers forms a securing location of the frame means to the rear ski member. 
     Advantageously, the first frame member supports the seat means. 
     Preferably, the headset pivotally supports the steering means which comprises a pair of handlebars attached to at least one fork member, a lower end of at least one fork member being attached to the forward ski member. 
     Advantageously, a pair of fork members are provided. 
     Advantageously, the handlebars at a location in the vicinity of the headset are shaped and spaced to accommodate a drag lift or other tow lift. 
     Preferably, the fork members are pivotally attached directly or indirectly to the forward ski member. 
     Advantageously, the forward ski member is pivotally attached to the fork members for movement about at least one of an axis which is transverse to the longitudinal direction of the frame means and an axis which is along the longitudinal direction of the frame means, both said axes being defined when the forward and rear ski members are aligned. 
     Advantageously, the rear ski member is pivotally attached to the frame means for movement about a longitudinal axis of the frame means. 
     In an embodiment of the invention the frame means is attached to the rear ski member by suspension means and, advantageously, the steering means may be attached to the forward ski member through the intermediary of one or more suspension members. 
     Where the front ski member is pivotally connected to the steering means, preferably means are provided for damping pivotal motion of said front ski member. 
     Advantageously, the frame means is attached to the rear ski member at longitudinally spaced locations of the frame and means are provided for permitting the rear ski member to flex between said spaced locations. 
     Preferably, said footrest means include an abrasive upper foot engaging surface. 
     In this invention the footrest means are located above the rear ski member giving substantial room for a user&#39;s feet to extend over the edge of the rear ski member, if desired, without the user&#39;s feet hitting the ground. A user is, thus, able to stand on the footrest means with their legs slightly apart giving a more natural stance during normal riding. The invention has the following advantages:
         1. A user can absorb greater vertical impact from a jump without exerting masses of forward or backward lean which impairs control and stability.   2. A user can take greater vertical impact from a jump, absorbing the pressure through the bike and the user&#39;s legs simultaneously.   3. A user can ride over rough ground more freely.   4. A user&#39;s feet are not restricted by skis, as in  FIG. 1 , or a strap, as in  FIG. 2 , so that a user is able to perform a greater number of popular freestyle manoeuvres.   5. Without the requirement of skis on a user&#39;s feet, as in  FIG. 1 , or the strap of  FIG. 2 , a user is less likely to sustain leg injury.   6. A user who has larger feet or who is wearing warmer, bulkier footwear will not have their performance restricted as in the prior art.       

    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention will now be described, by way of example, with reference to the accompanying drawings in which: 
         FIG. 1  shows a perspective view of a prior art snow-type bike known as a ski bob, 
         FIG. 2  shows a perspective view of a another prior art snow-type bike known as a snowscoot, 
         FIG. 3  shows a perspective view of a snow-type bike in accordance with this invention, known as a BOARDBIKE™, 
         FIG. 4  shows a partial side view of the snow-type bike of  FIG. 3 , 
         FIG. 5  shows a perspective view of a second embodiment of the present invention, 
         FIGS. 6(   a ) and  6 ( b ) show mutually orthogonal partial views of an alternative embodiment of a snow-type bike of this invention having a damper for pivotal motion of the forward ski, 
         FIG. 7  shows a partial side view of a rear ski member securement to a frame in an alternative embodiment of the snow-type bike of this invention, and 
         FIG. 8  shows a perspective view of a bracket used in the embodiment of  FIG. 7 . 
     
    
    
     DETAILED DESCRIPTION 
     In the Figures like reference numerals denote like parts. 
     The snow-type bike shown in  FIGS. 3 and 4  has a frame  50  formed of a first member  51  which forms a cross bar and a seat securement member, a second frame member  52  and a third frame member  53 , the third frame member having opposed ends attached to respective ends of the first and second members  51 ,  52 . Opposed ends of the frame members  51 ,  52  are secured to a headset  54 . The headset pivotally locates a handlebar stem  55  which forms a T-section with a cross member  56 . Opposed ends of the cross member  56  are attached to a respective one of a pair of user-operable handlebars  57  which are braced in the vicinity of the cross member  56  by a bar  58 . The outer ends of each handlebar  57  are provided with a hand grip  59 . The first member  51  carries at least one stay  60  and, preferably, there are two such stays  60  which support a seat  61 . The third frame member carries, on each lateral side thereof, a footrest  62  preferably having an abrasive upper foot engaging surface, e.g. spikes, for a user, the lateral width of the footrest depending on the size of the bike, which, in turn, will depend upon the size of a user. It is envisaged that the footrests  62  will be substantially the width of a user&#39;s footwear, although a slightly narrower footrest could be used, provided that the footrest was comfortable to a user. The footrest may, if desired, be located on an upper surface of the rear ski member. 
     Secured in the vicinity of the juxta position of the first and third frame members and the second and third frame members via brackets  64 ,  65  is a rear ski member  67  which is substantially parallel to the third frame member  53 . The rear ski member, preferably, has upturned front and rear ends and the rear ski member has a width substantially the same as that of the overall width of the footrest. However, if the footrest is located a sufficient height above the rear ski member, the footrest lateral width may be greater than that of the rear ski member. The reason for the rear ski member having substantially the same width as the footrest is so that the footrests do not contact the snow when cornering. Footrests are provided since, if a user places his or her feet directly on the rear ski member  67 , the board forming the rear ski member flexes and the load imparted by the user&#39;s feet on the rear ski member affects directional stability. 
     The stem  55  is preferably connected through bearings or bushes in the headset  54  to a pair of front forks  70 , although it is possible that a single fork member may be provided. The lower ends, in use, of the forks  70  are located in a U-shaped bracket  71  that attaches the forks to a forward ski member  72 . The forward ski member  72  may have an upturned front portion and the rear portion of the forward ski member  72  may also be upturned. The connection between the forks and the forward ski member  72  may be pivotally located to permit the ski member to move in the direction of double arrow-headed lines  73 , shown in  FIG. 4 . 
     Preferably, the forward and rear ski members have a width two or more times, preferably four times, the width of a normal recreation ski. 
     Conveniently, the front and rear ski members have the same width. However, as shown in  FIG. 3 , a rear portion of the rear ski member  67  located rearwardly of the rear most bracket  64  is arranged to be wider than the remainder of the member  67  which remainder has a substantially constant width. 
     It is also envisaged that the frame  50  and the front fork  70  may be attached to the rear and forward ski members by joints which permit the ski members to remain horizontal while the frame and forks tilt with respect thereto about a longitudinal axis of the frame, e.g. when cornering. 
     The handlebars  57  are shaped and arranged so as to accommodate between the respective handlebars a drag lift  75 , or other tow lift, shown in broken lines in  FIGS. 3 and 4 . In this respect, the handlebars are spaced so as to accept the drag lift pole  76 , but to retain an end  77  which may be an enlarged circular end, as shown, or a T-shaped end, so that the board bike may be carried up a slope by a drag lift. 
     Although not shown in  FIGS. 3 and 4 , the frame could be mounted onto the rear ski member via the intermediary of suspension means and similarly the front forks  70  may be attached to the forward ski member by suspension means. 
     Referring to  FIG. 5 , a second embodiment of the invention is shown in which the frame is mounted on the rear ski member via a suspension. 
     The snow-type bike of  FIG. 5  has a frame  80  formed in the shape of a letter Y, the stem  81  of the Y-shape having one end attached to a headset  98 , a first limb  82  of the Y-shape being secured to a seat  83  and via a suspension device including a pneumatic or hydraulic strut  84  to a pivot in a bracket  85  secured to a rear ski member  86 . The strut  84  is pivoted at its upper end to the first limb  82  and the strut is held in expansion by a compression spring  87 . Another limb  88  of the Y-shape is bifurcated with one portion of the bifurcation being attached to footrests  89  located on respective opposing sides of the limb  88  and the other portion of the bifurcation is pivotally mounted to a link device  90 . The link device  90  is formed of a first link  91  that has one end pivotally attached to the limb  88  and the other end thereof is pivotally attached to a further link  92 , the link  92  being pivotally located in a U-shaped saddle member  93  that is secured to a forward end of the rear ski member  86 . 
     The headset  98  pivotally supports the handlebars  57 . The headset  82  is positioned intermediate an upper triangular member  94  and a lower triangular member  95  at the apex of the members  94 ,  95  with a pair of pillars  96  being provided as supports at a respective corner of the members  94 ,  95 . Axially located below each of the pillars  96  on an opposite side of the lower triangular member  95  is a pair of front telescopic struts  97  which may be spring mounted. A lower end of the struts  97  are pivotally located on the U-shaped bracket  71  which is secured to the forward ski member  72 . 
     In this embodiment, the rear ski member  86  is suspended to the frame  80  and the forward ski member  72  is also suspended to the steering mechanism by the struts  97 . The front suspension in this embodiment is, however, optional. 
     The upper, foot engaging, surface of the footrests  62  and  89  may be provided with a high friction surface such as protruding spikes. 
     It will be understood that by having footrests located, in use, above the rear ski member  61 ,  86 , so a user may lean the board bike when negotiating a turn or bend without the user&#39;s feet contacting the ground, the amount of lean being dependent upon the height of the footrests above the rear ski member and the width of the rear ski member in relation to the width of the footrests although, as herein stated above, the width of both the rear and front ski members is more than twice and, preferably, four times the width of a normal recreational ski. The use of raised footrests also improves use of the snow-type bike for a user with larger feet or bigger boots. 
     A damper for a pivoting forward ski member is shown in  FIGS. 6(   a ) and  6 ( b ). The forks  70  are each pivotally attached by axles  110  that extend transversely to the longitudinal axis of the frame (the axis being defined when the forward and rear ski members are in alignment) to a transverse member  111  interconnecting the forks. Located below, in use, the member  111  is an elastomeric or rubber or other suitable resilient block  112 , acting as a damper, although it is to be understood that any suitable shock absorbing means known per se may be alternatively used. The block  112  is mounted on a plate  113  for transmitting load to the forward ski  72  at a location forward of the axles  110 . Not only does the damper block  112  damp pivoting of the forward ski, but it also permits a more controllable use of the snow-type bike, and also assists in reducing fracture of the forward ski member  72 . 
     If the frame members  51  and  52  are fixedly secured to the rear ski member  67 , it is possible that fracture of the rear ski member may occur. So as to reduce the risk of such fractures, the frame members  51  and  52  are fixedly or pivotally connected, as shown in  FIG. 7 , to a forward (in use) bracket  120  and a rearwardly mounted bracket  121 , the brackets  120 ,  121  being secured to the rear ski member  67  by rivets or bolts acting through resilient (e.g. rubber or elastomeric) bushings. Alternatively, the brackets  120 ,  121  may have a resilient member sandwiched between a lower surface of the brackets and an upper surface of the rear ski member  67 . 
     One of the brackets  121  is shown in detail in  FIG. 8 . The bracket has a generally U-shaped form having a base  125  and opposed side faces  126  each with a hole  127  for securement to the frame members  51 ,  52 . In a longitudinal direction of the frame the bracket has two pairs of slots  128  extending through the base  125 . The bracket  120  may also have similar slots  128  or may, alternatively, simply have circular holes. The slots  128  are fixing apertures for the bolts/rivets for attachment of the frame to the rear ski member  67 . Because of the provision of slots  128 , so the fixings which are resiliently mounted, and which are securely fixed to the board, are able to move with respect to the bracket  121 . Thus, if there should be flexing of the rear ski member  67 , such flexing is permitted by virtue of the slots  128 . 
     Although this invention has been described in relation to a snow-type bike for use in snow, it is envisaged that the BOARDBIKE™ could be used on water or a man-made ski slope, if so desired. 
     The present invention outperforms the snowscoot in its ability to turn more easily. This is due to the seat which is in a position that enables the user to lean against the frame with the inside of his or her leg to turn the bike effortlessly. The snowscoot does have a down frame member for this purpose, but it is not as effective. 
     On a snowscoot the user has to be right over the front thereof to make full use of the down frame member and once a rider leans backwards, the frame member disappears from their range. Even when in range, the amount of leverage gained from the frame member is not as much as when leaning against the BOARDBIKE™. This is because the seat of this invention may be soft and wide and a user of any size can use it to get leverage in all riding positions, even when they are leaning backwards away from the bike.