Abstract:
An endless track suspension is comprised of a suspension support beam having an idler wheel assembly connected to a respective one of opposed ends thereof. At least one of the idler wheel assemblies has an endless track binding mechanism. Support wheels are secured to the suspension support beam and project from a lower face thereof. A drive sprocket is secured elevated above the suspension support beam by a support arm. The drive sprocket is secured to a vehicle drive axle by a coupling ring. The drive sprocket, the support wheels and idler wheels constitute an endless track support assembly for supporting an endless track in drivable engagement thereabout. A flexible connection of the drive sprocket support arm and the support wheels absorbs shocks and vibrations transmitted to the vehicle drive axle by the displacement of the endless track over a rough ground surface.

Description:
CROSS-REFERENCE TO RELATED APPLICATION(S) 
       [0001]    The present application is a continuation in part of U.S. patent application Ser. No. 11/746,082, filed on May 9, 2007, and claims priority on Canadian Patent Application No. 2,552,119, filed on Jul. 12, 2006, by the present applicant. 
     
    
     TECHNICAL FIELD 
       [0002]    The present invention relates to an endless track suspension and particularly, but not exclusively, for use with all-terrain vehicles. 
       BACKGROUND ART 
       [0003]    Specifically, the endless track structure of the present invention is of the type wherein a suspension support beam is provided with idler wheels at opposed ends thereof with one of the wheels being adjustable to tension an endless track. A drive sprocket is connected to the support beam and adapted to connect to the drive axle of a vehicle whereby to impart rotation to the endless track supported about the idler wheels and the drive sprocket. Generally, this type of endless track structure is known in the art as disclosed, for example, by U.S. Pat. Nos. 6,318,484, 6,006,847 and 5,388,656. However, known prior art structures do not provide the flexibility, shock-damping features and adjustability that is required when such endless track structures are used on all-terrain vehicles where the vehicle is displaced at high speed over hard, rough terrain or snow. They also require many parts in their assembly and this leads to frequent break-downs and repairs. Some of these structures also use leaf-spring structures for shock absorption, therefore contributing to a heavy suspension assembly. 
       SUMMARY OF INVENTION 
       [0004]    It is a feature of the present invention to provide an endless track suspension which substantially overcomes the above-mentioned disadvantages of the prior art. 
         [0005]    Another feature of the present invention is to provide an endless track suspension assembly which is comprised of few component parts and which provides for a smooth shock-absorbing ride of a vehicle equipped with such endless track suspension. 
         [0006]    Another feature of the present invention is to provide an endless track suspension which is easy to assemble and disassemble and which provides ease of adjustment for the tensioning of the endless belt. 
         [0007]    Another feature of the present invention is to provide an endless track suspension wherein the drive sprocket is supported by a side arm which is secured to the support beam by a torsion pivot connection to provide shock damping. 
         [0008]    Another feature of the present invention is to provide an endless track suspension wherein the support wheels secured to the suspension support beam are secured by a torsion connection to provide shock damping. 
         [0009]    Another feature of the present invention is to provide an endless track suspension wherein an adjustable idler wheel is biased by an adjustable tensioning spring mechanism which is easily adjustable. 
         [0010]    Another feature of the present invention is to provide a drive sprocket coupling having an adaptor ring whereby the drive sprocket may be secured to different types of drive shaft connections. 
         [0011]    According to the above features, from a broad aspect, the present invention provides an endless track suspension having a suspension support beam provided with idler wheel assemblies at respective one of opposed ends of the support beam. At least one of the idler wheel assemblies has an endless track binding means. Support wheels are secured to the suspension support beam and project from a lower face of the support beam. A drive sprocket is secured elevated above the suspension support beam by a support means. Coupling means is connectable to the drive sprocket for securing same to a vehicle drive axle. The drive sprocket, the support wheels and idler wheels constitute an endless track support assembly for supporting an endless track in drivable engagement thereabout. Flexible suspension means is provided to absorb shocks and vibrations transmitted to the vehicle drive axle by the displacement of the endless track over a rough ground surface. 
         [0012]    According to the present disclosure, there is provided 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0013]    A preferred embodiment of the present invention will now be described with reference to the accompanying drawings in which: 
           [0014]      FIG. 1  is a perspective view showing the endless track suspension of the present invention supporting thereabout and in drivable engagement an endless track; 
           [0015]      FIG. 2  is a fragmented and partly section view illustrating the torsion pivot connection of the drive sprocket support arm; 
           [0016]      FIG. 3  is an exploded view showing the torsion connection of the support axle of the support wheel; 
           [0017]      FIG. 4  is a fragmented section view of a support wheel connected to the suspension support beam by the torsion connection; 
           [0018]      FIG. 5  is an exploded view illustrating the connecting parts of the drive sprocket to a vehicle drive axle; 
           [0019]      FIG. 6  is a section view showing the adaptor ring secured to the drive sprocket and a clamping cap; 
           [0020]      FIG. 7  is an exploded view showing the construction of the track binding mechanism; 
           [0021]      FIG. 8  is a further fragmented section view showing the binding mechanism in an assembled working condition; 
           [0022]      FIG. 9  is a perspective view of the endless track suspension provided with an adjustable slider bar connected to the support beam lower face and adjustable by displacement screws; 
           [0023]      FIG. 10  is a front view of  FIG. 9  showing the position of the slider bar with respect to the suspension support beam; and 
           [0024]      FIG. 11  is a section view along section-lines A-A of  FIG. 10  and again illustrating the construction of the slider bar assembly. 
       
    
    
     DESCRIPTION OF PREFERRED EMBODIMENTS 
       [0025]    Referring now to the drawings and more particularly to  FIG. 1 , there is shown generally at  10  the endless track suspension of the present invention. It is comprised of a suspension support beam  11  having an idler wheel assembly  12  and  13  at opposed ends  11 ′ and  11 ″ of the suspension support beam  11 . The idler wheel assembly  13  is a track binding idler wheel and as will be described later it provides a binding spring force against the inner surface  15 ′ of an endless track  15  trained over a portion thereof. 
         [0026]    The endless track suspension further comprises a drive sprocket  14  secured at an elevated position above the suspension support beam  11  by support means, herein a support arm  16 . A plurality of support wheels  17  are secured to the suspension support beam  11  and project from a lower face  18  thereof. These support wheels  17  are provided on opposed sides of the support beam  11 . As herehinshown there are two support wheels  17  on each side of the support beam. As also hereinshown the drive sprocket  14  is provided with sprocket teeth  14 ′ which are in engagement with sprocket receiving holes  19  provided all along a central longitudinal axis of the endless track  15 . Each idler wheel assembly  12  and  13  is comprised of a pair of wheels  12 ′ and  13 ′ each pair of wheels is supported on an axle  20  and  21 , respectively. The support arm is also secured to the suspension support beam  11  by a torsion pivot connection  22 . The upper end of the support arm is secured to a connecting shaft of a cap secured to the drive sprocket, as will be described, later and a cover  23  shields this connection from outside elements. 
         [0027]    Referring now to  FIG. 2 , there is shown the construction of the torsion pivot connection  22  and it is comprised by a connecting transverse hollow metal sleeve  24  secured to the lower end of the support arm  16  by suitable means such as welding or press-fit connection. A connecting metal shaft or rod  25  is immovably secured at one end in a connecting bore found in the support beam  11 . A rubber sleeve  26  is vulcanized about a projecting end portion  25 ′ of the connecting metal rod  25 . The projecting end portion  25 ′ extends into the transverse hollow metal sleeve  24  secured to the lower end of the support arm  16  with the rubber sleeve  26  vulcanized with the hollow metal sleeve. This rubber sleeve  26  provides limited torsional displacement of the connection of a support arm about the connecting rod  25 . 
         [0028]    Alternatively, any appropriate spring may be provided between the support beam  11  and the support arm  16 , to return the support beam  11  to a desired orientation of the support arm  16  after pivoting of one with respect to another by the pivot connection  22 . For instance, coil springs or leaf springs having opposed ends on the beam  11  and the arm  16  may dampen the movement of the support beam  11  with respect to the support arm  16 . 
         [0029]    Referring now to  FIG. 3 , there is shown the connection of the support wheels  17 . They are connected to the support beam  11  by a torsional axle connection constituted by a resilient support sleeve  28  disposed in an axle support bore  29  of the support beam  11 . The resilient support sleeve  28  may be a rubber support sleeve. The axle support bore  29  extends along a transverse axis of the support beam. An axle  30  of each of the support wheels  17  is received within the resilient support sleeve  28 . In an embodiment, the axle  30  is received in the rubber support sleeve  28  and vulcanized therein. The rubber support sleeve  28  may also be vulcanized within the axle support bore  29 . The outer end  31  of the axle is adapted to receive a ball bearing  32  which is press-fitted within the support wheel  17  and about the outer end  31  of the axle. The assembly once secured to the support beam  11  is illustrated in  FIG. 4  and as hereinshown the end of the axle  30  is provided with a fastener receiving bore for receiving a fastener (not shown) therein. Although the axle  30  is received in the resilient support sleeve  28 , any appropriate connection portion of the support wheel  17  may be connected to the support beam  11  by the resilient support sleeve  28 . 
         [0030]    Referring now to  FIGS. 5 and 6 , there is shown the construction of the drive sprocket  14  and a coupling means for securing same to a connecting end plate  34  of a vehicle drive axle  35 . Because these connecting end plates or couplers are different with different vehicle manufacturers or because of different types of vehicles, there is provided an adaptor ring  36  for these different types of couplers, whereby to couple these different types of drive axle connecting end plates  34  to the drive sprocket  14 . Accordingly it is not necessary to modify the drive sprocket for coupling same to different types of vehicle drive axles. The only requirement is to provide an adaptor ring suitable for coupling the connecting end plate to the drive sprocket. 
         [0031]    As hereinshown the adaptor ring  36  is provided with coupling locking formations  37  which are shaped for close fit reception in coupling cavities  38  provided on a connecting side wall  29  of the drive sprocket. The adaptor ring  36  is secured to projecting threaded bolts  34 ′ of the connecting end plate  34  which are received in holes  41  provided in the adaptor ring. Nuts, not shown, are used to secure the adaptor ring  36  to the bolts  34 ′ of the connecting end plate  34 . The drive sprocket is then fitted on the adaptor ring and secured thereto by a connecting cap  40 . The connecting cap  40  is secured in a cavity  42  formed in the opposed connecting hub side wall  39 ′. Securing bolts  43  secure the cap to the adaptor ring through the sprocket. As hereinshown the cap is also provided with a connecting shaft  45  to which the upper end of the support arm  16  is secured. 
         [0032]      FIG. 6  shows the assembly of the connecting cap  40 , the drive sprocket  14  and the adaptor ring  36  showing the mating of the coupling connecting formation  37  within the cavity  38  and a securement of the cap to the adaptor ring with the sprocket sandwiched therebetween. 
         [0033]    Referring now to  FIGS. 7 and 8 , there will be described the construction of an endless track binding means associated with the adjustable idler wheel  13 . This endless track binding means is comprised by a resilient means in the form of a helical spring  50  which is disposed captive in a bore  51  formed in an end wall  52  of the suspension support beam  11 . Adjustable compression means is provided in the form of a bolt  53  having at least a threaded end portion  54  which is threadably engaged in a transverse threaded connecting bore  55  formed in the support axle  21  of the adjustable idler wheels  13 ′. An adjustable nut  56  is threaded about the threaded free end portion  54  of the bolt  53  whereby to displace a plunger head  57  secured to the inner end of the bolt  53  and projectable within the bore  51  in which the helical spring  50  is disposed whereby to compress or decompress the spring  50 . The adjustable nut is made accessible from outside the endless track  15  through the sprocket receiving holes  19  formed in the track and which are aligned therewith. By the use of a ratchet-type tool the nut  56  can be rotated whereby to adjust the tension in the spring  51  to provide the proper binding force against the inner side wall  15 ′ of the endless track  15 . 
         [0034]      FIG. 8  shows the binding assembly in an assembled condition. The binding assembly is further provided with support guide means in the form of slide arms  60  and  60 ′ connected spaced-apart at one end to the support axle  21  and disposed on opposed sides of the bolt  53 . These slide arms are slidingly received in a respective one of guide channels  61  and  61 ′, respectively, formed in opposed side walls  62  of the support beam  11 , as clearly illustrated in  FIG. 7 . As hereinshown the slide arms  60 ,  60 ′ are elongated straight metal arms of U-shaped cross-section having a flat intermediate wall  63  disposed for sliding friction fit in a respective one of the rectangular guide channels  61  and  61 ′. The slide arms  60  prevent the support axle  21  from rocking motion with respect to the end wall  52  of the support beam  11 . Accordingly, the support guide means provides a rigid stable displacement structure when adjusting the binding force. 
         [0035]    Referring now to  FIGS. 9 to 11 , there is shown an adjustable slider bar  70  secured to the lower surface  18  of the suspension support beam  11 . This adjustable slider bar is a narrow bar as illustrated in  FIG. 10  and is centrally disposed along the lower surface  18  of the support beam  11  and it is configured to the shape of the lower surface and adjustably connected thereto by adjusting bolts  71  which extend through the support beam  11 . By threading the bolts the slider bar can be positioned closer to the inner surface  15 ′ of the endless track  15  whereby to provide better traction of the traction belt over snow surfaces making it easier to turn the vehicle. During non-winter months it can be retracted. These adjustable bolts  71  are easily accessible from opposed sides of the track in the large space provided over the support beam. Also because the support arm  16  is a side arm, it provides easy access to the bolts located adjacent the sprocket wheel from the opposed sides of the support beam, that is to say the side opposed to the torsion pivot connection  22 . 
         [0036]    As previously described the endless track suspension of the present invention was designed particularly to be coupled to the drive shafts of all terrain vehicles such as four wheel vehicles or vehicles having rear traction wheels and a front steering ski for use on snow. However, it is intended not to restrict the invention to these vehicles as it is conceivable that such suspension can be used on other types of land vehicles for recreational or industrial use. 
         [0037]    It is within the ambit of the present invention to cover any obvious modifications of the preferred embodiment described herein provided such modifications fall within the scope of the appended claims.