Patent Document

CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]     This application is a continuation of U.S. patent application Ser. No. 10/165,707 filed Jun. 6, 2002, now pending, which was a continuation-in-part of U.S. patent application Ser. No. 10/087,103 filed Feb. 27, 2002, now abandoned, the specifications of which are hereby incorporated by reference. 
     
    
     TECHNICAL FIELD  
       [0002]     The present invention relates to all-terrain vehicles. More specifically, the present invention is concerned with track assemblies for an all-terrain vehicle.  
       BACKGROUND OF THE INVENTION  
       [0003]     Traditionally, two types of all-terrain vehicles are proposed either the wheel type or the tracked type.  
         [0004]     Generally, a wheeled vehicle is more maneuverable than a tracked vehicle, but is not as efficient on uneven or soft terrain such as, for example snow.  
         [0005]     Tracked all-terrain vehicles have been proposed, which require complicated track assemblies comprising a track frame to maintain the tension of the endless track belt and prevent it from loosening. Furthermore, such vehicles have generally a large contact area with the ground, which results in a decreased maneuverability and an increased impact on the often soft terrain.  
         [0006]     Therefore, there is still room for improvements toward an all-terrain vehicle provided with track assemblies, which is maneuverable and effective upon a variety of unstable or uneven surfaces, while designed to maintain tension upon the endless track belts to keep them in their due course and prevent accidental loosening, and at the same time reducing the damages inflicted on the terrain.  
       SUMMARY OF THE INVENTION  
       [0007]     An object of the present invention is therefore to provide improved track assemblies for an all-terrain vehicle.  
         [0008]     More specifically, in accordance with the present invention, there is provided an all-terrain vehicle comprising at least two track assemblies to support the all-terrain vehicle onto a ground surface, each one of the at least two track assemblies comprising: a longitudinal endless track belt having with an inner surface provided with a plurality of inner lugs and an outer surface provided with a plurality of external lugs; a track driving wheel having a peripheral portion operatively engaged with the endless track belt to drive the endless track belt; at least one inside wheel and at least one outside wheel, each having a peripheral portion in contact with the endless track belt, the endless track belt being wounded around the track driving wheel, the at least one inside wheel, and the at least one outside wheel, the lower peripheral portion of the at least one inside wheel and the at least one outside wheel in contact with the endless track belt being above the lower peripheral portion of the track driving wheel in contact with the endless track belt; a mounting structure to mount the longitudinal endless track belt to the vehicle, the longitudinal endless track belt mounted on the mounting structure defining substantially a scalene triangle; whereby, when the vehicle is disposed on a flat surface only a portion of the endless track bell under the track driving wheel is in contact with the flat surface.  
         [0009]     In accordance with another aspect of the present invention, there is provided an endless track belt assembly comprising: a track driving wheel having a peripheral portion provided with a plurality of teeth; an endless track belt provided with an inner surface having a plurality of inner lugs and an outer surface having a plurality of external lugs, the inner lugs of the endless track belt operatively engaging the teeth of the track driving wheel; and at least one inside wheel and at least one outside wheel, each having a peripheral portion in contact with the endless track belt, the endless track belt being wounded around the track driving wheel, the at least one inside wheel, and the at least one outside wheel and defining substantially a scalene triangle, the lower portion of the at least one inside wheel and the at least one outside wheel in contact with the endless track belt being above the lower portion of the track driving wheel in contact with the endless track belt.  
         [0010]     In accordance with another aspect of the present invention, there is provided a method for mounting an endless track belt on a all-terrain vehicle, comprising the acts of: providing an endless track belt having inner lugs and external lugs; providing a track driving wheel being operatively engaged with the endless track belt; interconnecting the track driving wheel to at least one inside wheel and at least one outside wheel, the at least one inside wheel being mounted closer to the track driving wheel than the at least one outside wheel; tensioning the endless track belt around the track driving wheel, the at least one inside wheel, and the at least one outside wheel, each having a peripheral portion in contact with the endless track belt, the lower peripheral portion of the at least one inside wheel and the at least one outside wheel in contact with the endless track belt being above the lower peripheral portion of the track driving wheel in contact with the endless track belt.  
         [0011]     Other objects, advantages and features of the present invention will become more apparent upon reading of the following nonrestrictive description of preferred embodiments thereof, given by way of example only with reference to the accompanying drawings. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0012]     In the appended drawings:  
         [0013]      FIG. 1 . is a side elevational view of an all-terrain vehicle provided with track assemblies according to an embodiment of the present invention;  
         [0014]      FIG. 2 . is a side elevational view of the front track assembly of the vehicle of  FIG. 1 , seen from of the outside of the all-terrain vehicle;  
         [0015]      FIG. 3 . is a side elevational view of the front track assembly of the vehicle of  FIG. 1 , seen form the inside of the all-terrain vehicle;  
         [0016]      FIG. 4 . is a sectional view taken along the line  4 - 4  of  FIG. 3 ;  
         [0017]      FIG. 5 . is an enlarged side view of an outside idler wheel attachment of the track assembly of  FIG. 2 ;  
         [0018]      FIG. 6 . is a sectional view of a rigid member of the track assembly of  FIG. 2 ;  
         [0019]      FIG. 7 . is a top plan view of the attachment of the front track assembly of  FIG. 1  to the all-terrain vehicle;  
         [0020]      FIG. 8 . is a side elevational view of a rear track assembly of  FIG. 1 , seen from the inside of the all-terrain vehicle;  
         [0021]      FIG. 9 . is a top plan view of the attachment of the rear track assembly of  FIG. 1  to the all-terrain vehicle;  
         [0022]      FIG. 10 . is a sectional view similar to  FIG. 4  but illustrating a second type of endless track; and  
         [0023]      FIG. 11 . is a sectional view similar to  FIG. 4  but illustrating a third type of endless track. 
     
    
       [0024]     It will be noted that throughout the appended drawings, like features are identified by like reference numerals.  
       DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0025]     A track assembly for an all-terrain vehicle according to an embodiment of the present invention will now be described in details with reference to the appended drawings.  
         [0026]      FIG. 1  shows an all-terrain vehicle  10  comprising a body  12  and four track assemblies (only two shown) according to the present invention arranged in a plane adjacent to each side of the vehicle  10 .  
         [0027]     There are two identical track assemblies in the front of the all-terrain vehicle  10 , of which only one track assembly  14  is visible in  FIG. 1 , in place of conventional front wheels. Similarly, there are two identical track assemblies, of which only one track assembly  16  is visible in  FIG. 1 , in place of the conventional rear wheels.  
         [0028]     Only the track assemblies  14  and  16  visible in  FIG. 1  will be described hereinbelow. Furthermore, as they are symmetrical about a vertical axis  22  when viewed from the outside of the vehicle  10  (see  FIG. 1 ), only the track assemblies  14  will be described hereinbelow. It is also to be noted that the elements as seen from the outside of the vehicle  10  will bear the same numbers in the rear track assembly  16  than the corresponding ones in the front track assembly  14 , with a prime.  
         [0029]     However, since the attachment of rear and front track assemblies differs as seen from the inside of the vehicles  10 , they will be described separately.  
         [0030]     The front track assembly  14  is better seen in  FIG. 2 . It comprises a longitudinal endless track belt  23  and a mounting structure to mount the endless track belt  23  to the vehicle  10 . The mounting structure includes a track driving wheel  24 , a pair of inside idler wheels  26 , a pair of outside idler wheels  28  and supports to interconnect the wheels  24 ,  26  and  28  as will be described hereinbelow.  
         [0031]     The endless track belt  23  is provided with inner lugs  30  on its inner surface  31  and with external lugs  32  on its outer surface  33 . It is wounded around the track driving wheel  24  and the idler wheels  28  and  26 .  
         [0032]     As can be better seen from  FIG. 4 , the track driving wheel  24  is mounted to a conventional hub  35  of the all-terrain vehicle  10 . The wheel  24  includes a first mounting plate  37  mounted to the hub  35  and a second mounting plate  34  mounted to the first plate  37  via four bolt and spacer assemblies  36 . A circular disk  38  is mounted to the bolt and spacer assemblies  36  and includes equidistant wide teeth  40  contacting the inner surface  31  of the track  23 .  
         [0033]     As will be apparent to one skilled in the art, the equidistant teeth  40  are so located as to cooperate with some of the inner lugs  30  of the endless track belt  23 . More precisely, as can be better seen from  FIG. 2 , the teeth  40  are spaced so that the distance between two consecutive teeth  40  spans the distance separating consecutive inner lugs  30  of the endless track belt  23 , in a meshing engagement, in such a way as to drive the endless track belt  23 .  
         [0034]     Each of the inside idler wheels  26  includes a peripheral portion in contact with the internal surface  31  of the track  23 . The wheels  26  are interconnected by a spacing element (not shown).  
         [0035]     Similarly, each outer idler wheel  28  includes a peripheral portion in contact with the internal surface  31  of the track  23 . The wheels  28  are interconnected by a spacing element  42 .  
         [0036]     The wheels  24 ,  26  and  28  are interconnected, as seen from the outside of the track assembly  14 , by an angled connecting element  44 . The angled connecting element  44  has a center portion  46  provided with an aperture  48  in which bearings  50  are mounted. A fastener  52  connects the connecting element  44  to the second plate  34  while allowing the angled connecting element  44  to pivot about the fastener.  
         [0037]     The connecting element  44  has a short arm  54  having a free end to which the inside idler wheels  26  are rotatably mounted. The connecting element  44  also has a long arm  56  having a free end to which the inside idler wheels  28  are rotatably mounted as will be further discussed hereinbelow. Referring to  FIG. 2 , it is seen that the endless track belt  23  is wounded around the wheels  24 ,  26 , and  28  and defines a substantially scalene triangle since the connecting element  44  has a short and a long arms  54 ,  56 . The connecting element  44  is better seen from the top plan view of  FIG. 6 .  
         [0038]     Turning now briefly to  FIG. 3  of the appended drawings, as can be seen from the inside of the all-terrain vehicle  10 , the idler wheels  26  and  28  of the front track assembly  14  are also directly connected together by an elbowed connection element  58 . The inside idler wheels  26  are rotatably mounted to a first end of the elbowed connection element  58  while the outside idler wheels  28  are rotatably mounted to a second end of the elbowed connection element  58 .  
         [0039]     The rotatable connection of the outside idler wheels  28  to the angle connection element  44  and to the elbowed connection element  58  will now be described with reference to  FIG. 5 .  
         [0040]     As will easily be understood by one skilled in the art upon inspection of  FIG. 5 , the tension of the endless track belt  23  is adjusted by the connection of the outside idler wheels  28  to the elements  44  and  58 . For concision purpose, only the connection of the wheels  28  to the elbowed connection element  58  will be described.  
         [0041]     With reference to the enlarged side view of  FIG. 5 , a tension adjusting assembly according to another aspect of the present invention will be described. As can be seen from this figure, a distal end of the connection element  58  includes a slotted aperture  60  receiving a fastener  62  used to rotatably mount the wheels  28  to the assembly. By sliding the fastener  62  in the aperture  60 , it is possible to increase or decrease the tension on the track  23 . To adjust and maintain this track tension, a cam element  64 , having an outer periphery provided with notches  66  located at different distances from the attachment point of the element  64 , is mounted to the fastener  62 . By selecting which notch  66  is in contact with a fixed pin  68  of the element  58 , a predetermined tension may be maintained. It is to be noted that the cam element  64  is provided with a handle  70  to facilitate the manipulation by a user.  
         [0042]     Returning to  FIG. 4  of the appended drawings the endless track  23  will be described in greater detail.  
         [0043]     As can be seen from  FIG. 4 , the overall profile of the track  23 , from one side to the other, i.e. transversely, is generally convex. However, the convex profile of the track  23  is created by a lug arrangement comprising two successive transverse rows of lugs arranged in a staggered relationship.  
         [0044]     A first transverse row of lugs contains three lugs  72 ,  74  and  76  and a second row of lugs contains four lugs  78 ,  80 ,  82  and  84 . These lugs are symmetrical about a longitudinal axis (not shown).  
         [0045]     A first lateral lug  72  of the first row includes three ground-contacting surfaces separated by two indentations. The shape of lateral lug  72  is such that the ground contacting surfaces are generally transversally convex.  
         [0046]     A central lug  74  is centered about longitudinal axis and includes two ground-contacting surfaces separated by an indentation. The ground contacting surfaces are symmetrical about the longitudinal axis and are generally transversally convex.  
         [0047]     A second lateral lug  76  is a mirror image of lug  72  about the longitudinal axis.  
         [0048]     The first and second lateral lugs  72  and  76  are laterally spaced apart from the central lug  74 .  
         [0049]     In the second transverse row of lugs, a first intermediate lug  80  includes two ground-contacting surfaces separated by an indentation. The ground engaging surfaces are slightly transversally convex.  
         [0050]     A first external lug  78  includes two ground-contacting surfaces that are separated by an indentation and are transversally convex.  
         [0051]     Finally, the second intermediate lug  82  and the second external lug  84  are respectively mirror images of lugs  80  and  78  with respect to the longitudinal axis. For concision purposes, these lugs will not be further described herein.  
         [0052]     Of course, the sequences described hereinabove of the lug arrangement defined by the rows of lugs are repeated onto the entire external surface of the endless track  23 .  
         [0053]     The endless track belt  23  further includes, for each row of lugs, a stiffening rod  71 , made of glass fibers for example. Each stiffening rod  71  is embedded in the material forming the track belt  23  so as to be generally parallel to the inner surface  31  thereof. The rods  71  provide enhanced rigidity to the endless track belt  23 . The enhanced rigidity of the track belt  23  has many advantages. For example, it helps the track to provide adequate traction even when the center portion of the track is not in direct contact with the ground, as illustrated in  FIG. 4 . However, it has been found that this type of traction may be detrimental to the steering of the vehicle in some conditions.  
         [0054]     As it is apparent from  FIG. 4  the ground contacting surfaces of symmetrical lugs  78  and  84  are not aligned with the outer surfaces of the other lugs to form a continuous profile. Indeed, the ground contacting surfaces of lugs  78  and  84  are more angled and exceed the convex profile defined by the other lugs. This configuration of the outer lugs is advantageous since it further prevents the vehicle from tipping over during sharp turns at high speed when the vehicle  10  is severely tilted.  
         [0055]     As mentioned hereinabove, the way the front track assembly  14  is attached to the body  12  of the vehicle  10  differs from the way the rear track assembly  16  is attached to the body  12  of the vehicle  10 . These two attachments will be described hereinbelow.  
         [0056]     The front track assembly  14  is attached to the body  12  of the vehicle  10  in a fashion shown in  FIGS. 4 and 7 , while the rear track assembly  16  is attached to the body  12  of the vehicle  10  in a fashion shown in  FIGS. 8 and 9 .  
         [0057]     As seen in  FIGS. 4 and 7 , the front track assembly  14  is mounted to a tubular wheel table  100  of the vehicle  10  by means of a generally triangular plate  102  fastened thereto by a plurality of U-bolts  104 ,  106 ,  108  and  110 . A rod  112  is connected between the elbowed connection element  58  and a pivot  114  of the tubular wheel table  100 . A first end of the rod  112  is attached to the elbowed connection element  58  by means of rubber damping elements  116 , in such a way as to allow a vertical movement at this point of the rod  112  in relation to the elbowed connection element  58 . A second end of the rod  112  is attached to the pivot  114  of the tubular wheel table  100  by means of an R-clip  120 , in such a way as to allow at this point a horizontal movement of the plate  102  holding the tubular wheel table  100  relative to the elbowed connection element  58 .  
         [0058]     The front track assembly  14  is further attached to the body  12  of the vehicle  10  through a conventional rod  150  of the suspension system of the vehicle  10  and a conventional rod  157  used for direction (see  FIG. 4 ).  
         [0059]     As seen in  FIGS. 8 and 9 , the rear track assembly  16  is mounted to the body  12  of the vehicle  10  by a rod  212 . The rod  212  is connected on a first end to the elbowed connection element  58 ′ by means of a rubber damping attachment  216 . It is attached, on a second end, to a tubular chassis  130  of the body  12  of the vehicle  10  by means of a chipping joint  132  fastened thereto by an R-clip  134 .  
         [0060]     From the above description of the fashion in which the front and rear track assemblies  14  and  16  are mounted to the body  12  of the vehicle  10 , in relation to  FIGS. 4 and 7 , and  8  and  9  respectively, the present invention provides for track assemblies that are easily removed or mounted to the vehicle  10 , through using R-clips ( 120  and  134 ), which enable disconnecting the track assemblies from the vehicle in a simple manner.  
         [0061]     As stated hereinabove, the interior surface  31  of the endless track belt  23  is provided with a plurality of equally spaced lugs  30 , which ensure a positive engagement with the teeth  40  provided on the outer circumference of the wheel  24 . In operation, the wheel  24  is coupled to a drive shaft, via the hub  30 , connected to an engine (not shown), in such a way that the engine drives the wheel  24  in rotation. The wheel  24  thus drives the endless track belt  23  by the meshing engagement of the teeth  40  with the internal lugs  30  of the endless track belt  23 .  
         [0062]     It is further to be understood that the external lugs  32  on the external circumference surface of the endless track belt  23  respectively exert a positive mechanical connection with the underlying ground surface that contributes to propel the vehicle  10 .  
         [0063]      FIG. 10  and  FIG. 11  show sectional views similar to that of  FIG. 4  but illustrating variants of an endless track that may be mounted to the track assembly of the present invention.  
         [0064]     In  FIG. 10 , the overall profile of the endless track belt  23   a,  from one side to the other, i.e. transversely, is generally convex.  
         [0065]     The convex profile of the endless track belt  23   a  is created by the same lug arrangement as that described hereinabove in relation to  FIG. 4 . In this specific embodiment however, the endless track belt  23   a  does not include stiffening rods under each row of lugs. Consequently, the rigidity of the endless track belt  23   a  is less than the rigidity of the endless track belt  23  ( FIG. 4 ) and the profile of the endless track belt  23   a  conforms itself to the profile of the ground. Since the pressure is more localized in the center of the endless track belt  23   a,  a more punctually localized contact zone between the endless track belt  23   a  and the ground  29  is created. In many cases, this punctually localized contact zone makes the vehicle  10  more maneuverable.  
         [0066]     Turning now to  FIG. 11 , a third version of an endless track belt  23   b  will be described. The endless track belt  23   b  is wounded around the track driving wheel  24  and the idler wheels  28  and  26 , is still provided with inner lugs  30  on its inner surface  31 . However, its outer surface is provided with rectangular lugs  86 . Since there are no stiffening rods in the endless track belt  23   b,  the endless track belt  23   b  is free to conform itself to the ground  29 , as seen in  FIG. 11 . Furthermore, since the pressure is exerted only in the middle of the endless track belt  23   b  by the wide teeth  40 , a punctually localized contact zone between the endless track belt  23   b  and the ground  29  is created.  
         [0067]     As will be apparent to one skilled in the art, the endless track belts  23   a  has a particularly punctually localized contact surface with the ground  29 . Indeed, since it is transversally convex, it generally contacts the ground  29  with a limited surface at any given time when the ground  29  is hard.  
         [0068]     Furthermore, since there are no guiding rails for the endless track belts  23 ,  23   a  or  23   b,  the external lugs only exert a pressure on the ground  29 , when it is hard, in the vicinity of the wide teeth  40  if the wheel  24 . Referring to  FIGS. 1, 2 ,  3 , and  8 , it will be seen that the lower peripheral portion of the track driving wheel  24  in contact with the endless track belt  23  is below the lower peripheral portion of the idler wheels  26 ,  28  in contact with the endless track belt  23 . Therefore, on flat ground surfaces, only a punctually localized surface of endless track belt  23 , under the track driving wheel;  24 , is in contact with ground  29 . Even on uneven ground surfaces, the contact surface is reduced since only a portion of the endless track belt  23  is in contact with ground  29 . These three combined features improve the maneuverability of the vehicle since it emulates the contact of a conventional tire onto hard ground, given that a shortened length of contact of the endless track with the ground surface reduces the resistance to a turning force.  
         [0069]     Of course, one skilled in the art could designed another convex profile of the external lugs of the endless track belts  23  and/or another arrangement of the mounting assembly of the endless track belts  23  to the vehicle  10  to obtain this “one point contact” feature without departing from the spirit and nature of the present invention. For example, one could provide a guiding rail having a convex profile and transversally convex lugs to achieve similar results.  
         [0070]     As people in the art will understand, the all-terrain vehicle of the present invention, provided with four endless track assemblies, can be used for a wide range of operations and terrain, while being highly mobile and offering good running performance.  
         [0071]     The endless track structure maintains an adequate configuration over a variety of surfaces.  
         [0072]     It will be obvious to people skilled in the art that the present invention can be applied both in the case of a two-wheel drive vehicle wherein the power is typically applied only to the rear track belt assemblies and the front track assemblies merely facilitate steering, and in the case of a four-wheel vehicle, wherein power is independently provided to each one of the four track assemblies.  
         [0073]     As will be further understood by one skilled in the art, the all-terrain vehicle  10 , equipped with track assemblies according to the present invention, may be viewed as a snow vehicle since it may be used on snow as efficiently as conventional snow vehicles such as snowmobiles, for example. However, the one-point contact feature of the present invention allows the use of the all-terrain vehicle on harder surface without the usual drawbacks of tracked vehicles.  
         [0074]     Interestingly, the present track assembly system can equip all four wheels of an all-terrain vehicle or only the front or rear wheels thereof, since it only weakly reduces the speed of the vehicle relative to the underground surface.  
         [0075]     A further possibility would be to use track assemblies according to the present invention in place of the rear wheels of a vehicle, while mounting skis in place of the front wheels thereof.  
         [0076]     Although the present invention has been described hereinabove by way of preferred embodiments thereof, it can be modified, without departing from the spirit and nature of the subject invention as defined in the appended claims.  
         [0077]     While illustrated in the block diagrams as groups of discrete components communicating with each other via distinct data signal connections, it will be understood by those skilled in the art that the preferred embodiments are provided by a combination of hardware and software components, with some components being implemented by a given function or operation of a hardware or software system, and many of the data paths illustrated being implemented by data communication within a computer application or operating system. The structure illustrated is thus provided for efficiency of teaching the present preferred embodiment.  
         [0078]     It should be noted that the present invention can be carried out as a method, can be embodied in a system, a computer readable medium or an electrical or electro-magnetical signal.  
         [0079]     The embodiment(s) of the invention described above is(are) intended to be exemplary only. The scope of the invention is therefore intended to be limited solely by the scope of the appended claims.

Technology Category: 7