Track assembly for an all-terrain vehicle (atv) or other tracked vehicle

Abstract

A track assembly for providing traction to an all-terrain vehicle (ATV) or other tracked vehicle. The track assembly may comprise a wheel device for contacting an inner side of an endless track such that a longitudinal end segment of the endless track turns around the wheel device. The wheel device allows a change in curvature of the longitudinal end segment of the endless track when the longitudinal end segment of the endless track contacts an obstacle on the ground. In some embodiments, the wheel device may comprise a resilient wheel that is elastically deformable. In other embodiments, the wheel device may comprise a wheel carrier carrying a plurality of carried wheels.

1 - 47 . (canceled) 
     
     
         48 . A track assembly for traction of a vehicle, the track assembly comprising:
 a) a track comprising a ground-engaging outer side for engaging the ground and an inner side opposite to the ground-engaging outer side; and   b) a track-engaging arrangement for driving and guiding the track around the track-engaging arrangement, a bottom run of the track extending under the track-engaging arrangement, the track-engaging arrangement comprising:
 i. a frame; 
 ii. a drive wheel for driving the track; 
 iii. an idler wheel adjacent to a longitudinal end of the track assembly and contacting the bottom run of the track; and 
 iv. a wheel-carrying structure carrying the idler wheel and turnable relative to the frame about an axis to change a shape of the track, the idler wheel being rotatable relative to the wheel-carrying structure, an axis of rotation of the idler wheel being different from the axis about which the wheel-carrying structure is turnable. 
   
     
     
         49 . The track assembly of  claim 48 , wherein the axis of rotation of the idler wheel is raised when the wheel-carrying structure turns relative to the frame in a first direction and lowered when the wheel-carrying structure turns relative to the frame in a second direction opposite to the first direction. 
     
     
         50 . The track assembly of  claim 48 , wherein the wheel-carrying structure is turnable relative to the frame such that the axis of rotation of the idler wheel is movable from a first position above the axis about which the wheel-carrying structure is turnable to a second position below the axis about which the wheel-carrying structure is turnable 
     
     
         51 . The track assembly of  claim 48 , wherein: the idler wheel is a front idler wheel; the longitudinal end of the track assembly is a front longitudinal end of the track assembly; and the track-engaging arrangement comprises a rear idler wheel adjacent to a rear longitudinal end of the track assembly and contacting the bottom run of the track. 
     
     
         52 . The track assembly of  claim 51 , wherein the frame comprises an elongated member extending from the wheel-carrying structure to the rear idler wheel. 
     
     
         53 . The track assembly of  claim 52 , wherein the elongated member is configured to diverge from the ground towards the wheel-carrying structure. 
     
     
         54 . The track assembly of  claim 53 , wherein the elongated member is configured to diverge from the ground towards the rear idler wheel. 
     
     
         55 . The track assembly of  claim 51 , wherein: the track-engaging arrangement comprises a plurality of support wheels disposed between the front idler wheel and the rear idler wheel in a longitudinal direction of the track assembly and contacting the bottom run of the track; and the axis about which the wheel-carrying structure is turnable is higher than an axis of rotation of a given one of the support wheels. 
     
     
         56 . The track assembly of  claim 48 , wherein the axis about which the wheel-carrying structure is turnable and the axis of rotation of the idler wheel are parallel. 
     
     
         57 . The track assembly of  claim 48 , wherein the frame is mounted about an axis of rotation of the drive wheel. 
     
     
         58 . The track assembly of  claim 51 , wherein the frame has a pivot point located between the front idler wheel and the rear idler wheel in a longitudinal direction of the track assembly. 
     
     
         59 . The track assembly of  claim 58 , wherein the pivot point of the frame corresponds to an axis of rotation of the drive wheel. 
     
     
         60 . The track assembly of  claim 51 , wherein the axis of rotation of the front idler wheel and an axis of rotation of the rear idler wheel are movable relative to an axis of rotation of the drive wheel when the track assembly moves on the ground. 
     
     
         61 . The track assembly of  claim 51 , wherein a distance between an axis of rotation of the drive wheel and the axis of rotation of the front idler wheel in a longitudinal direction of the track assembly is different from a distance between the axis of rotation of the drive wheel and an axis of rotation of the rear idler wheel in the longitudinal direction of the track assembly. 
     
     
         62 . The track assembly of  claim 48 , wherein a distance between the axis of rotation of the idler wheel and the axis about which the wheel-carrying structure is turnable is greater than a radius of the idler wheel. 
     
     
         63 . The track assembly of  claim 51 , wherein: the track-engaging arrangement comprises a plurality of support wheels disposed between the front idler wheel and the rear idler wheel in a longitudinal direction of the track assembly; and a distance between the axis of rotation of the front idler wheel and the axis about which the wheel-carrying structure is turnable is less than a distance between the axis about which the wheel-carrying structure is turnable and an axis of rotation of a given one of the support wheels that is closest to the wheel-carrying structure. 
     
     
         64 . The track assembly of  claim 48 , wherein: the idler wheel is a first idler wheel; the track-engaging arrangement comprises a second idler wheel spaced apart from the first idler wheel in a widthwise direction of the track assembly; the wheel-carrying structure carries the second idler wheel; the second idler wheel is rotatable relative to the wheel-carrying structure; and an axis of rotation of the second idler wheel is different from the axis about which the wheel-carrying structure is turnable. 
     
     
         65 . The track assembly of  claim 48 , wherein the inner side of the track comprises a plurality of wheel-contacting projections for contacting at least one of the drive wheel and the idler wheel. 
     
     
         66 . The track assembly of  claim 65 , wherein the wheel-contacting projections are drive projections and the drive wheel comprises a sprocket for engaging the drive projections. 
     
     
         67 . The track assembly of  claim 48 , wherein the wheel-carrying structure comprises an arm carrying the idler wheel and extending away from the axis about which the wheel-carrying structure is turnable. 
     
     
         68 . The track assembly of  claim 48 , wherein the idler wheel is one of a plurality of idler wheels carried by the wheel-carrying structure. 
     
     
         69 . The track assembly of  claim 68 , wherein the plurality of idler wheels comprises at least three idler wheels disposed around the axis about which the wheel-carrying structure is turnable. 
     
     
         70 . The track assembly of  claim 68 , wherein the wheel-carrying structure comprises a plurality of arms carrying respective ones of the idler wheels and extending away from the axis about which the wheel-carrying structure is turnable. 
     
     
         71 . The track assembly of  claim 48 , wherein the wheel-carrying structure is configured to turn relative to the frame in response to the track assembly contacting an obstacle on the ground. 
     
     
         72 . The track assembly of  claim 71 , wherein the wheel-carrying structure is configured to turn relative to the frame in a first direction if the obstacle has a first size and turn relative to the frame in a second direction opposite to the first direction if the obstacle has a second size different from the first size. 
     
     
         73 . The track assembly of  claim 48 , wherein the wheel-carrying structure is turnable relative to the frame such that the axis of rotation of the idler wheel is movable relative to the frame to change an orientation of a segment of the bottom run of the track extending from the idler wheel to an adjacent part of the track-engaging arrangement in contact with the bottom run of the track relative to the frame. 
     
     
         74 . The track assembly of  claim 73 , wherein: the track-engaging arrangement comprises a plurality of guiding wheels contacting the bottom run of the track; the idler wheel is one of the plurality of guiding wheels; and the adjacent part of the track-engaging arrangement in contact with the bottom run of the track is an adjacent one of the guiding wheels. 
     
     
         75 . The track assembly of  claim 73 , wherein the orientation of the segment of the bottom run of the track extending from the idler wheel to the adjacent part of the track-engaging arrangement in contact with the bottom run of the track relative to the frame defines a first angle relative to a longitudinal direction of the track assembly when the axis of rotation of the idler wheel is in a first position relative to the frame and defines a second angle relative to the longitudinal direction of the track assembly when the axis of rotation of the idler wheel is in a second position relative to the frame, the second angle being substantially different from the first angle. 
     
     
         76 . The track assembly of  claim 48 , wherein the wheel-carrying structure is turnable relative to the frame such that the axis of rotation of the idler wheel is movable relative to the frame to create an inflexion point in the bottom run of the track. 
     
     
         77 . The track assembly of  claim 48 , wherein the track assembly is steerable by operating a steering device of the vehicle to change an orientation of the track assembly relative to the vehicle. 
     
     
         78 . An all-terrain vehicle (ATV) comprising a set of four track assemblies, wherein each of at least two of the four track assemblies is as claimed in  claim 48 . 
     
     
         79 . A track assembly for traction of a vehicle, the track assembly comprising:
 a) a track comprising a ground-engaging outer side for engaging the ground and an inner side opposite to the ground-engaging outer side; and   b) a track-engaging arrangement for driving and guiding the track around the track-engaging arrangement, a bottom run of the track extending under the track-engaging arrangement, the track-engaging arrangement comprising:
 i. a frame; 
 ii. a drive wheel for driving the track; and 
 iii. an idler wheel adjacent to a longitudinal end of the track assembly and contacting the bottom run of the track, an axis of rotation of the idler wheel being movable relative to the frame to change a shape of the track. 
   
     
     
         80 . The track assembly of  claim 79 , wherein the axis of rotation of the idler wheel is movable relative to the frame to change an orientation of a segment of the bottom run of the track extending from the idler wheel to an adjacent part of the track-engaging arrangement in contact with the bottom run of the track relative to the frame. 
     
     
         81 . The track assembly of  claim 80 , wherein: the track-engaging arrangement comprises a plurality of guiding wheels contacting the bottom run of the track; the idler wheel is one of the plurality of guiding wheels; and the adjacent part of the track-engaging arrangement in contact with the bottom run of the track is an adjacent one of the guiding wheels. 
     
     
         82 . The track assembly of  claim 79 , wherein the orientation of the segment of the bottom run of the track extending from the idler wheel to the adjacent part of the track-engaging arrangement in contact with the bottom run of the track relative to the frame defines a first angle relative to a longitudinal direction of the track assembly when the axis of rotation of the idler wheel is in a first position relative to the frame and defines a second angle relative to the longitudinal direction of the track assembly when the axis of rotation of the idler wheel is in a second position relative to the frame, the second angle being substantially different from the first angle. 
     
     
         83 . The track assembly of  claim 79 , wherein the axis of rotation of the idler wheel is movable relative to the frame to create an inflexion point in the bottom run of the track. 
     
     
         84 . The track assembly of  claim 79 , wherein: the track-engaging arrangement comprises a wheel-carrying structure carrying the idler wheel and turnable relative to the frame about an axis to move the axis of rotation of the idler wheel in order to change the shape of the track; the idler wheel is rotatable relative to the wheel-carrying structure; and the axis of rotation of the idler wheel is different from the axis about which the wheel-carrying structure is turnable. 
     
     
         85 . The track assembly of  claim 84 , wherein the axis of rotation of the idler wheel is raised when the wheel-carrying structure turns relative to the frame in a first direction and lowered when the wheel-carrying structure turns relative to the frame in a second direction opposite to the first direction. 
     
     
         86 . The track assembly of  claim 84 , wherein the wheel-carrying structure is turnable relative to the frame such that the axis of rotation of the idler wheel is movable from a first position above the axis about which the wheel-carrying structure is turnable to a second position below the axis about which the wheel-carrying structure is turnable 
     
     
         87 . The track assembly of  claim 79 , wherein: the idler wheel is a front idler wheel; the longitudinal end of the track assembly is a front longitudinal end of the track assembly; and the track-engaging arrangement comprises a rear idler wheel adjacent to a rear longitudinal end of the track assembly and contacting the bottom run of the track. 
     
     
         88 . The track assembly of  claim 87 , wherein the frame comprises an elongated member extending between the front idler wheel and the rear idler wheel. 
     
     
         89 . The track assembly of  claim 88 , wherein the elongated member is configured to diverge from the ground towards the front idler wheel. 
     
     
         90 . The track assembly of  claim 89 , wherein the elongated member is configured to diverge from the ground towards the rear idler wheel. 
     
     
         91 . The track assembly of  claim 84 , wherein: the idler wheel is a front idler wheel; the longitudinal end of the track assembly is a front longitudinal end of the track assembly; the track-engaging arrangement comprises a rear idler wheel adjacent to a rear longitudinal end of the track assembly and contacting the bottom run of the track, and a plurality of support wheels disposed between the front idler wheel and the rear idler wheel in a longitudinal direction of the track assembly and contacting the bottom run of the track; and the axis about which the wheel-carrying structure is turnable is higher than an axis of rotation of a given one of the support wheels. 
     
     
         92 . The track assembly of  claim 79 , wherein the frame is mounted about an axis of rotation of the drive wheel. 
     
     
         93 . The track assembly of  claim 87 , wherein the frame has a pivot point located between the front idler wheel and the rear idler wheel in a longitudinal direction of the track assembly. 
     
     
         94 . The track assembly of  claim 93 , wherein the pivot point of the frame corresponds to an axis of rotation of the drive wheel. 
     
     
         95 . The track assembly of  claim 79 , wherein the axis of rotation of the idler wheel is movable relative to an axis of rotation of the drive wheel when the track assembly moves on the ground. 
     
     
         96 . The track assembly of  claim 87 , wherein a distance between an axis of rotation of the drive wheel and the axis of rotation of the front idler wheel in a longitudinal direction of the track assembly is different from a distance between the axis of rotation of the drive wheel and an axis of rotation of the rear idler wheel in the longitudinal direction of the track assembly. 
     
     
         97 . The track assembly of  claim 84 , wherein a distance between the axis of rotation of the idler wheel and the axis about which the wheel-carrying structure is turnable is greater than a radius of the idler wheel. 
     
     
         98 . The track assembly of  claim 79 , wherein: the idler wheel is a first idler wheel; the track-engaging arrangement comprises a second idler wheel spaced apart from the first idler wheel in a widthwise direction of the track assembly; and an axis of rotation of the second idler wheel is movable relative to the frame to change the shape of the track. 
     
     
         99 . The track assembly of  claim 79 , wherein the inner side of the track comprises a plurality of wheel-contacting projections for contacting at least one of the drive wheel and the idler wheel. 
     
     
         100 . The track assembly of  claim 99 , wherein the wheel-contacting projections are drive projections and the drive wheel comprises a sprocket for engaging the drive projections. 
     
     
         101 . The track assembly of  claim 84 , wherein the wheel-carrying structure comprises an arm carrying the idler wheel and extending away from the axis about which the wheel-carrying structure is turnable. 
     
     
         102 . The track assembly of  claim 84 , wherein the idler wheel is one of a plurality of idler wheels carried by the wheel-carrying structure. 
     
     
         103 . The track assembly of  claim 102 , wherein the plurality of idler wheels comprises at least three idler wheels disposed around the axis about which the wheel-carrying structure is turnable. 
     
     
         104 . The track assembly of  claim 102 , wherein the wheel-carrying structure comprises a plurality of arms carrying respective ones of the idler wheels and extending away from the axis about which the wheel-carrying structure is turnable. 
     
     
         105 . The track assembly of  claim 79 , wherein the axis of rotation of the idler wheel is movable relative to the frame in response to the track assembly contacting an obstacle on the ground. 
     
     
         106 . The track assembly of  claim 105 , wherein the axis of rotation of the idler wheel is movable relative to the frame in a first direction if the obstacle has a first size and movable relative to the frame in a second direction opposite to the first direction if the obstacle has a second size different from the first size. 
     
     
         107 . The track assembly of  claim 79 , wherein the track assembly is steerable by operating a steering device of the vehicle to change an orientation of the track assembly relative to the vehicle. 
     
     
         108 . An all-terrain vehicle (ATV) comprising a set of four track assemblies, wherein each of at least two of the four track assemblies is as claimed in  claim 79 . 
     
     
         109 . A track assembly for traction of a vehicle, the track assembly comprising:
 a) a track comprising a ground-engaging outer side for engaging the ground and an inner side opposite to the ground-engaging outer side; and   b) a track-engaging arrangement for driving and guiding the track around the track-engaging arrangement, a bottom run of the track extending under the track-engaging arrangement, the track-engaging arrangement comprising:
 i. a frame; 
 ii. a drive wheel for driving the track; and 
 iii. a plurality of guiding wheels contacting the bottom run of the track, the plurality of guiding wheels including an idler wheel adjacent to a longitudinal end of the track assembly, an axis of rotation of the idler wheel being movable relative to the frame to change an orientation of a segment of the bottom run of the track extending from the idler wheel to an adjacent one of the guiding wheels relative to the frame. 
   
     
     
         110 . The track assembly of  claim 109 , wherein the orientation of the segment of the bottom run of the track extending from the idler wheel to the adjacent one of the guiding wheels relative to the frame defines a first angle relative to a longitudinal direction of the track assembly when the axis of rotation of the idler wheel is in a first position relative to the frame and defines a second angle relative to the longitudinal direction of the track assembly when the axis of rotation of the idler wheel is in a second position relative to the frame, the second angle being substantially different from the first angle. 
     
     
         111 . The track assembly of  claim 109 , wherein the axis of rotation of the idler wheel is movable relative to the frame to create an inflexion point in the bottom run of the track beneath the adjacent one of the guiding wheels. 
     
     
         112 . The track assembly of  claim 109 , wherein: the track-engaging arrangement comprises a wheel-carrying structure carrying the idler wheel and turnable relative to the frame about an axis to move the axis of rotation of the idler wheel in order to change the orientation of the segment of the bottom run of the track extending from the idler wheel to the adjacent one of the guiding wheels relative to the frame; the idler wheel is rotatable relative to the wheel-carrying structure; and the axis of rotation of the idler wheel is different from the axis about which the wheel-carrying structure is turnable. 
     
     
         113 . The track assembly of  claim 112 , wherein the wheel-carrying structure is turnable relative to the frame such that the axis of rotation of the idler wheel is movable from a first position above the axis about which the wheel-carrying structure is turnable to a second position below the axis about which the wheel-carrying structure is turnable 
     
     
         114 . The track assembly of  claim 109 , wherein: the idler wheel is a front idler wheel; the longitudinal end of the track assembly is a front longitudinal end of the track assembly; and the plurality of guiding wheels includes a rear idler wheel adjacent to a rear longitudinal end of the track assembly. 
     
     
         115 . The track assembly of  claim 114 , wherein: the plurality of guiding wheels includes a plurality of support wheels disposed between the front idler wheel and the rear idler wheel in a longitudinal direction of the track assembly. 
     
     
         116 . The track assembly of  claim 114 , wherein the frame has a pivot point located between the front idler wheel and the rear idler wheel in a longitudinal direction of the track assembly. 
     
     
         117 . The track assembly of  claim 109 , wherein the axis of rotation of the idler wheel is movable relative to an axis of rotation of the drive wheel when the track assembly moves on the ground. 
     
     
         118 . The track assembly of  claim 109 , wherein the axis of rotation of the idler wheel is movable relative to the frame in response to the track assembly contacting an obstacle on the ground. 
     
     
         119 . The track assembly of  claim 109 , wherein the track assembly is steerable by operating a steering device of the vehicle to change an orientation of the track assembly relative to the vehicle. 
     
     
         120 . An all-terrain vehicle (ATV) comprising a set of four track assemblies, wherein each of at least two of the four track assemblies is as claimed in  claim 109 .