Abstract:
A snow vehicle is disclosed comprising a vehicle frame, a propulsion unit coupled to the frame, and a front ski steered by a steering mechanism. The front of the vehicle includes a first front suspension and a second front suspension coupled to the ski. The rear suspension includes a bumper assembly preventing bottoming out of the rear suspension. The rear suspension is coupled to the vehicle frame such that the longitudinal spacing between the vehicle frame and rear suspension is adjustably controllable.

Description:
BACKGROUND 
     The present disclosure relates to snow vehicles including snowmobiles and or snow bikes and in particular a front suspension for the same. 
     Many types of vehicles are configured with tracks to drive in the snow. Regardless of whether the vehicle is a snowmobile or a wheeled vehicle converted to a tracked vehicle, tracked vehicles typically include a front suspension system that supports the ski and is coupled to the frame. In the case of snow bikes, the front suspension comprises the suspension of the motorbike or dirt bike, that is, a front shock absorber. In the case of snowmobiles, the front suspension is typically includes two control arms, also known as double A-arms. However the front snowmobile suspension can also be a trailing arm suspension. The suspension described herein would typically supplement any of the front suspensions discussed above, although it could also be the primary suspension. 
     One such snow vehicle is shown in our U.S. Pat. No. 8,910,738, the subject matter of which is incorporated herein by reference. This patent discloses a conversion of a motorbike into a snow vehicle where the motorbike powertrain is utilized to power the track of the converted snow vehicle. 
     SUMMARY 
     In a first embodiment, a snow vehicle comprises a frame; a propulsion unit coupled to the frame; at least one front ski; a steering mechanism coupled to the frame; a first front suspension coupled to the frame; a second front suspension positioned intermediate the first front suspension and the at least one ski; a rear suspension coupled to the frame, the rear suspension comprising: at least one slide rail; at least one control arm coupled between the slide rail and the frame; at least linear force element coupled between the slide rail and the frame; and at least one carrier roller coupled to the at least one slide rail; and a drive system comprising a drive track slidably guided by the at least one slide rail and drivably coupled to the propulsion unit. 
     In a second embodiment, a front suspension for a snow vehicle comprises a spindle body; a knuckle for coupling to a ski of the snow vehicle; and at least one control arm coupled intermediate the spindle body and to the knuckle. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention will now be described in relation to the drawing Figures where: 
         FIG. 1  is a side view of one of the embodiments of snow vehicle as disclosed in the present disclosure; 
         FIG. 2A  shows a left front perspective view of the front suspension coupled to the snow vehicle; 
         FIG. 2B  is a front suspension similar to that of  FIG. 2A  showing the front suspension coupled to a conventional snowmobile; 
         FIG. 3  is a front left perspective view of the suspension assembly; 
         FIG. 4  is a rear right perspective view of the suspension assembly of  FIG. 3 ; 
         FIG. 5  is a view similar to that of  FIG. 3  showing the suspension in an exploded manner; 
         FIG. 5A  is an enlarged portion of the linkage assembly shown in  FIG. 5 ; 
         FIG. 5B  is an enlarged portion of the shock absorber mounting as shown in  FIG. 5 ; 
         FIG. 6A  shows a side view of the front suspension coupled to a ski in the fully extended position; and 
         FIG. 6B  shows the front suspension of  FIG. 6 a    in a full trounce position; 
     
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
     With reference first to  FIG. 1 , a snow vehicle is shown generally at  2  as comprised of a motorcycle portion  4  having a propulsion unit  5 , which is shown as a two-cylinder motorcycle engine, a frame  6 , an operators seat  8 , and a steering assembly  10  which includes a front fork  12 . A first suspension member is shown at  14  as a shock absorber assembly axially coupled with the forks  12 . A second front suspension assembly is shown at  16  which couples the steering assembly  10  directly to a ski  18 . A full description of the entire snow vehicle is described in our co-pending patent application Ser. No. 14/935,224, filed Nov. 6, 2015 and incorporated herein by reference. 
     A rear suspension assembly  20  is shown having an upper frame portion  22 , slide rails  24 , carrier rollers  25 , side panels  26 , control arms  28 ,  30 , linear force elements  32  and  34  (shown as shock absorbers) and an endless belt or drive track  36 . As shown, the control arms  28 ,  30  and the linear force elements  32  and  34  are coupled between the slide rail  24  and the frame  22 . A carrier roller  25  is coupled to the slide rail  24 . A drive system  36  comprising a drive track  40  is slidably guided by the slide rail  24  and is drivably coupled to the propulsion unit  5 . 
     With reference now to  FIGS. 2A and 3-5 , the front suspension assembly  16  will be described in greater detail. As shown best in  FIGS. 3 and 4 , front suspension assembly  16  generally includes a spindle body  40 , a lower linkage portion  42 , and a mounting portion  44 . As shown best in  FIG. 5 , spindle portion  40  is generally comprised of two plates  50  and  52  where each plate includes a plurality of apertures. Namely, plate  50  includes apertures  50   a - 50   g  together with an enlarged aperture at  50   h . Likewise, plate  52  includes apertures  52   a - 52   g  and an enlarged aperture at  52   h . Spindle portion  40  also includes a plurality of spacers to space the plates  50  and  52  apart, namely spacers  54   a ,  54   b ,  54   c , and  54   g . An enlarged spacer is provided at  54   h . It should be noted each of the spacers  54   a ,  54   b ,  54   c , and  54   g  are somewhat spool-shaped having an enlarged head portion  56  at each end as well as threaded openings  58  at each end. Enlarged spacer  54   h  is embossed at each end to define a reduced diameter section  60  defining shoulders  62 . 
     Thus, the spindle portion may be preassembled by placing the reduced diameter portion  60  of spacer  54   h  into respective apertures  50   h  and  52   h . This positions the reduced diameter portion  60  through the corresponding apertures  50   h  and  52   h  as shown in  FIGS. 3 and 4 . Spacers  54   c  and  54   g  may then be aligned with corresponding apertures  50   c ,  52   c ; and  50   g ,  52   g . Fasteners and washers may then be positioned against plates  50  and  52  to retain the two plates together and coupled to the spacers. Namely, fastener  70   c  and washer  72   c  may be aligned with aperture  52   c  and brought into threaded engagement with threaded aperture  58  of spacer  54   c . Likewise, fasteners  70   g  and washers  72   g  may be received through apertures  50   g  and  52   g  to be received into the threaded ends  58  of spacer  54   g . The fasteners should be brought into engagement with the threaded apertures of their corresponding spacers but not fully torqued down at this position as other spacers and assembly is required within the spindle assembly. 
     With reference still to  FIG. 5 , mounting portion  44  is shown including clamp halves  80 ,  82 ;  84 ,  86 . Each of the pairs of clamp halves includes semi-cylindrical openings which may encompass the front forks of the motorcycle frame as described above with reference to  FIG. 1 . Thus, spacers  54   a  and  54   b  are now aligned with respective pairs of apertures  50   a ,  50   b ;  52   a  and  52   b ; and fasteners  70   a  and  70   b  are received through their respective apertures as shown in  FIG. 5 . This brings fasteners into engagement with the threaded ends  58  of the corresponding spacers  54   a  and  54   b  to a position where the clamp may be closed. 
     With reference now to  FIG. 5A , the link assembly  42  is shown and will be described in greater detail. As shown best in  FIG. 5A , link assembly  42  includes front links or control arms  100  and rear links or control arms  102 . Each control arm  100  includes an upper coupling  100   a  and a lower coupling at  100   b . Likewise, control arms  102  include upper couplings at  102   a  and lower couplings at  102   b . Each of the upper couplings  100   a  and  102   a  receive sleeves  104  which are profiled to be received in the couplings  100   a ,  102   a . Spacers  106  and  108  respectively, are then inserted through corresponding couplings  100   a ,  102   a  and into sleeves  104 . Likewise, spacer  108  is received into couplings  102   a , and into sleeves  104 . Thus, control arms  100  and  102  may be aligned with respective apertures  50   e ,  52   e , and  50   f ,  52   f  ( FIG. 5 ) and fastened to the spindle assembly by way of fasteners and washers  70   e ,  72   e  and  70   f ,  72   f.    
     With reference again to  FIG. 5A , linkage assembly  42  further includes a knuckle  110  having a front pivot coupling  110   a  having an aperture at  110   b  and a rear pivot coupling  110   c  having an aperture  110   d . Sleeves  112  may be received in lower couplings  100   b  of control arms  100  (in the orientation shown in  FIG. 5A ) and then couplings  100   b  may be received in alignment with apertures  110   b  whereupon fasteners  114   a  and washers  114   b  may be aligned with threaded apertures  110   b  to couple control arms  100  with the knuckle  110 . In a like manner, sleeves  116  may be received in lower couplings  102   b  (in the orientation shown in  FIG. 5A ) whereby couplings  102   b  and sleeves  116  are received over rear pivot coupling  110   c  and in alignment with threaded apertures  110   d . Thereafter, fasteners  120   a  and washers  120   b  may be aligned with sleeves  116  to couple alignment arms  102  with knuckle  110 . 
     Finally, with reference to  FIG. 5B , linkage  42  further includes a shock absorber  124  having a lower coupling at aperture  124   a  and an upper coupling at aperture  124   b . Split sleeves  126  include reduced diameter portions  126   a  and threaded apertures at  126   b . Split sleeves  126  may be positioned with reduced diameter portions  126   a  in apertures  124   b  and the shock may be coupled to the spindle assembly by way of fasteners  70   d  and washers  70   e  positioned through apertures  50   d  ( FIG. 5 ) and into threaded engagement with threaded apertures  126   b . The lower aperture  124   a  of shock  124  may then be coupled to bracket arms  102   c  as shown in  FIG. 5B . Sleeves  130  are positioned with reduced diameter portions  130   a  within the shock aperture  124   a . The sleeves  130  and the shock aperture  124   a  are then aligned with apertures  102   d  whereupon fastener  140  may be received through sleeves  130 , apertures  102   d  and receive a fastener  142  and lock washer  144 . Thus, the entire assembled second suspension system  16  is shown in  FIGS. 3 and 4  where knuckle  110  is shown as providing an aperture  110   e  for coupling to ski  18  as shown above in  FIG. 2A . That is, ski  18  includes ski rails  18   a  whereby a pin  18   b  may be received through the rails and into aperture  110   e  for retaining ski  18  to the second suspension system  16 . Ski  18  could be similar to that shown in U.S. Pat. No. 8,381,857, the subject matter of which is incorporated herein by reference. 
     Thus, in operation and with reference to  FIGS. 6A and 6B , ski  18  is shown in a fully extended position in  FIG. 6A  and in a full trounce position in  FIG. 6B . As shown in  FIG. 6B , control arms  100  and  102  are shown collapsed with the shock absorber  124  in a stroked position. Advantageously, the ski is lifted up and rearwardly relative to spindle assembly  40 . It is lifted upwardly in the sense that it rotated (in the clockwise sense as viewed in  FIG. 6B ). It is rotated in the range of 1-5°. It also moves rearwardly, for example, the position of the pin  18   b  which couples the ski to knuckle  110  moves rearwardly from the positions shown in  FIG. 6A  to the position shown in  FIG. 6B . That is, the distance in  FIG. 6A  between the upper pivot point of front control arm  100  (about fastener  70   e ) is shown as X 1 , whereas in  FIG. 6 b    the distance is shown as X 2 , where X 2  is greater than X 1 . This provides an enhanced suspension system in that the ski is lifted up and rearward; for example, if the snowbike is going over a rock or log, the ski is lifted up and over the log rather than pushing the ski into the log. This movement also reduces the friction between the ski and the snow due to the lifting of the ski. 
     It should be understood that the spindle assembly may also be usable on a conventional snowmobile, and as shown in  FIG. 2B , spindle  16 ′ is shown coupled to upper and lower alignment arms or control arms  150 ,  152 , where upper control arm  150  is coupled to spindle assembly  16 ′ by way of a ball joint at  154 . Although not shown in  FIG. 2B , lower control arm  152  would also be coupled by way of a ball joint to spindle assembly  16 ′. It should be further understood that spindle assembly  16  or  16 ′ could be adapted for use with a trailing arm type snowmobile suspension of the type shown in U.S. Pat. No. 6,328,124, the subject matter of which is incorporated herein by reference. 
     While this invention has been described as having an exemplary design, the present invention may be further modified within the spirit and scope of this disclosure. This application is therefore intended to cover any variations, uses, or adaptations of the invention using its general principles. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which this invention pertains.