CA2886719A1

CA2886719A1 - Track assembly for an all-terrain vehicle

Info

Publication number: CA2886719A1
Application number: CA2886719A
Authority: CA
Inventors: Denis Boivin; Alain Boivin; Denis Courtemanche
Original assignee: Camoplast Solideal Inc
Current assignee: Camso Inc
Priority date: 2002-02-25
Filing date: 2002-05-30
Publication date: 2003-08-25
Anticipated expiration: 2022-05-30
Also published as: CA2854554A1; CA2854554C; CA2886719C; CA2372949A1

Abstract

The present invention is concerned with track assemblies for an all-terrain vehicle, which make it maneuverable and effective upon a variety of unstable, uneven, stable and even surfaces, while designed to maintain tension upon the endless track belts to keep them in their due course and prevent accidental loosening while having a punctually localized surface contact with a ground surface, and at the same time reducing the damages inflicted on the terrain. For instance, a lower run of each endless track belt of the front track assemblies may be curved and/or may converge toward and diverge from the ground between respective leading and trailing idler wheels of the front track assemblies, and/or the endless track belts may be free of stiffening inserts extending transversally to the longitudinal direction of the endless track belts and disposed within a flexible material of the endless track belts.

Description

TITLE OF THE INVENTION
Track assembly for an all-terrain vehicle FIELD OF THE INVENTION
[0001] 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

[0002] Traditionally, two types of all-terrain vehicles are proposed either the wheel type or the tracked type.

[0003] 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.

[0004] 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.

[0005] 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 damages inflicted on the terrain.
OBJECTS OF THE INVENTION

[0006] An object of the present invention is therefore to provide improved track assemblies for an all-terrain vehicle.
SUMMARY OF THE INVENTION
[0006A] In accordance with an aspect of the present invention, there is provided an endless track for a track assembly providing traction to an all-terrain vehicle (ATV). The track assembly is substitutable to a ground-engaging wheel of the ATV and is steerable by changing an orientation of the track assembly by a steering mechanism of the ATV. The track assembly comprises a plurality of wheels and the endless track is mountable around the plurality of wheels. The plurality of wheels includes a drive wheel for imparting motion to the endless track. The endless track comprises an inner surface for facing the plurality of wheels, a ground-engaging outer surface opposite to the inner surface, and a plurality of traction projections projecting from the ground-engaging outer surface and spaced apart in a longitudinal direction of the endless track. The endless track is free of stiffening members extending in a transversal direction of the endless track at locations of respective ones of the traction projections in the longitudinal direction of the endless track.
[0006B] In accordance with another aspect of the present invention, there is provided a track assembly for providing traction to an all-terrain vehicle (ATV). The track assembly is substitutable to a ground-engaging wheel of the ATV and is steerable by changing an orientation of the track assembly by a steering mechanism of the ATV. The track assembly comprises a plurality of wheels and an endless track mounted around the plurality of wheels. The plurality of wheels includes a drive wheel, a leading idler wheel and a trailing idler wheel spaced apart from the leading idler wheel in a longitudinal direction of the track assembly. The endless track comprises an inner surface for facing the plurality of wheels, a ground-engaging outer surface opposite the inner surface and a plurality of traction projections projecting from the ground-engaging outer surface and spaced apart in a longitudinal direction of the endless track. The drive wheel is rotatable to impart motion to the endless track. The endless track is free of stiffening members extending in a transversal direction of the endless track at locations of respective ones of the traction projections in the longitudinal direction of the endless track.
[0006C] In accordance with another aspect of the present invention, there is provided an endless track for a track assembly providing traction to an all-terrain vehicle (ATV). The track assembly is substitutable to a ground-engaging wheel of the ATV and is steerable by changing an orientation of the track assembly by a steering mechanism of the ATV. The track assembly comprises a plurality of wheels around which the endless track is mountable. The plurality of wheels includes a drive wheel for imparting motion to the endless track. The endless track comprises an inner surface for facing the plurality of wheels, a ground-engaging outer surface opposite to the inner surface, a plurality of wheel-contacting lugs projecting from the inner surface to contact the plurality of wheels, and a plurality of traction projections projecting from the ground-engaging outer surface and spaced apart in a longitudinal direction of the endless track. The endless track is free of stiffening members extending in a transversal direction of the endless track at locations of respective ones of the wheel-contacting lugs in the longitudinal direction of the endless track.
[0006D] In accordance with another aspect of the present invention, there is provided a track assembly for providing traction to an all-terrain vehicle (ATV). The track assembly is substitutable to a ground-engaging wheel of the ATV and is steerable by changing an orientation of the track assembly by a steering mechanism of the AN. The track assembly comprises a plurality of wheels and an endless track mounted around the plurality of wheels. The plurality of wheels includes a drive wheel, a leading idler wheel and a trailing idler wheel spaced apart from the leading idler wheel in a longitudinal direction of the track assembly. The endless track comprises an inner surface for facing the plurality of wheels, a ground-engaging outer surface opposite to the inner surface, a plurality of wheel-contacting lugs projecting from the inner surface to contact the plurality of wheels, and a plurality of traction projections projecting from the ground-engaging outer surface and spaced apart in a longitudinal direction of the endless track. The drive wheel is rotatable to impart motion to the endless track. The endless track is free of stiffening members extending in a transversal direction of the endless track at locations of respective ones of the wheel-contacting lugs in the longitudinal direction of the endless track.
[0006E] In accordance with another aspect of the present invention, there is provided an endless track for a reduced-size vehicle designed primarily for off-highway usage, over undeveloped roads or other unprepared surfaces. The endless track is steerable by changing an orientation of the endless track by a steering mechanism of the vehicle. The endless track comprises flexible material to flex around a plurality of wheels including a drive wheel for imparting motion to the endless track. The endless track comprises a ground-engaging outer surface, an inner surface opposite to the ground-engaging outer surface, and a plurality of traction projections projecting from the ground-engaging outer surface and distributed in a longitudinal direction of the track. The endless track is free of stiffening inserts extending in a transversal direction of the endless track and disposed within the flexible material at locations of respective ones of the traction projections in the longitudinal direction of the endless track.
[0006F] In accordance with another aspect of the present invention, there is provided a track assembly for a reduced-size vehicle designed primarily for off-highway usage, over undeveloped roads or other unprepared surfaces. The track assembly is steerable by changing an orientation of the track assembly by a steering mechanism of the vehicle. The track assembly comprises a plurality of wheels and an endless track mounted around the plurality of wheels. The plurality of wheels includes a drive wheel as well as a leading idler wheel and a trailing idler wheel spaced apart from one another in a longitudinal direction of the track assembly. The endless track comprises flexible material to flex around the plurality of wheels. The endless track comprises an inner surface for facing the plurality of wheels.
The drive wheel is rotatable to impart motion to the endless track. The endless track further comprises a ground-engaging outer surface opposite to the inner surface and a plurality of traction projections projecting from the ground-engaging outer surface and spaced apart in a longitudinal direction of the endless track. The endless track is free of stiffening inserts extending in a transversal direction of the endless track and disposed within the flexible material at locations of respective ones of the traction projections in the longitudinal direction of the endless track.
[0006G] In accordance with another aspect of the present invention, there is provided an endless track for a reduced-size vehicle designed primarily for off-highway usage, over undeveloped roads or other unprepared surfaces. The endless track is steerable by changing an orientation of the endless track by a steering mechanism of the vehicle. The endless track comprises flexible material to flex around a plurality of wheels including a drive wheel for imparting motion to the endless track. The endless track comprises a ground-engaging outer surface, an inner surface opposite to the ground-engaging outer surface, a plurality of wheel-contacting lugs projecting from the inner surface to contact the plurality of wheels, and a plurality of traction projections projecting from the ground-engaging outer surface and distributed in a longitudinal direction of the track. The endless track is free of stiffening inserts extending in a transversal direction of the endless track and disposed within the flexible material at locations of respective ones of the wheel-contacting lugs in the longitudinal direction of the endless track.
[0006H] In accordance with another aspect of the present invention, there is provided a track assembly for a reduced-size vehicle designed primarily for off-highway usage, over undeveloped roads or other unprepared surfaces. The track assembly is steerable by changing an orientation of the track assembly by a steering mechanism of the vehicle. The track assembly comprises a plurality of wheels and an endless track mounted around the plurality of wheels. The plurality of wheels includes a drive wheel as well as a leading wheel and a trailing idler wheel spaced apart from one another in a longitudinal direction of the track assembly. The endless track comprises flexible material to flex around the plurality of wheels. The endless track comprises an inner surface for facing the plurality of wheels. The drive wheel is rotatable to impart motion to the endless track. The endless track further comprises a ground-engaging outer surface opposite to the inner surface, a plurality of wheel-contacting lugs projecting from the inner surface to contact the plurality of wheels, and a plurality of traction projections projecting from the ground-engaging outer surface and spaced apart in a longitudinal direction of the endless track. The endless track is free of stiffening inserts extending in a transversal direction of the endless track and disposed within the flexible material at locations of respective ones of the wheel-contacting lugs in the longitudinal direction of the endless track.

[0007] In accordance with another aspect of 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 said at least two track assemblies comprising: a longitudinal endless track belt provided with an inner surface provided with a plurality of inner lugs and an outer surface provided with a plurality of external lugs; a mounting structure to mount said longitudinal endless track belt to said vehicle, wherein, when mounted to said mounting structure, said longitudinal endless track belt has a punctually localized surface contact with the ground surface.

[0008] In accordance with another aspect of the present invention, there is provided an endless track belt assembly comprising: a track driving wheel 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, said endless track belt being wounded around said track driving wheel; wherein a) said teeth are so spaced that a distance between two consecutive teeth spans a distance separating two consecutive inner lugs of said endless track belt and b) said endless track belt, when mounted to said track driving wheel, has a punctually localized contact with a ground surface.

[0009] 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 having a plurality of teeth so spaced that a distance between two consecutive of the plurality of teeth spans a distance separating two consecutive of a plurality of inner lugs of the endless track belt;
interconnecting the track driving wheel to an inside idler wheel and to an outside idler wheel; and tensioning the endless track belt around the track driving wheel, the inside idler wheel and the outside idler wheel so that the endless track belt has a punctually localized surface contact with a ground surface.

[0010] 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

[0011] In the appended drawings:

[0012] Figure 1 is a side elevational view of an all-terrain vehicle provided with track assemblies according to an embodiment of the present invention;

[0013] Figure 2 is a side elevational view of the front track assembly of the vehicle of Figure 1, seen from of the outside of the all-terrain vehicle;

[0014] Figure 3 is a side elevational view of the front track assembly of the vehicle of Figure 1, seen form the inside of the all-terrain vehicle;

[0015] Figure 4 is a sectional view taken along the line 4-4 of Figure 3;

[0016] Figure 5 is an enlarged side view of an outside idler wheel attachment of the track assembly of Figure 2;

[0017] Figure 6 is a sectional view of a rigid member of the track assembly of Figure 2;

[0018] Figure 7 is a top plan view of the attachment of the front track assembly of Figure 1 to the all-terrain vehicle;

[0019] Figure 8 is a side elevations, view of a rear track assembly of Figure 1, seen from the inside of the all-terrain vehicle;

[0020] Figure 9 is a top plan view of the attachment of the rear track assembly of Figure 1 to the all-terrain vehicle;

[0021] Figure 10 is a sectional view similar to Figure 4 but illustrating a second type of endless track; and

[0022] Figure ills a sectional view similar to Figure 4 but illustrating a third type of endless track.
DESCRIPTION OF THE EMBODIMENT

[0023] 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.

[0024] Figure 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.

[0025] 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 Figure 1, in place of conventional front wheels. Similarly, there are two identical track assemblies, of which only one track assembly 16 is visible in Figure 1, in place of the conventional rear wheels.

[0026] Only the track assemblies 14 and 16 visible in Figure 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 Figure 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.

[0027] 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.

[0028] The front track assembly 14 is better seen in Figure 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.

[0029] 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.

[0030] As can be better seen from Figure 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.

[0031] 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 Figure 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.

[0032] 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).

[0033] 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.

[0034] 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.

[0035] 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. The connecting element 44 is better seen from the top plan view of Figure 6.

[0036] Turning now briefly to Figure 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.

[0037] 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 Figure 5.

[0038] As will easily be understood by one skilled in the art upon inspection of Figure 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.

[0039] With reference to the enlarged side view of Figure 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.

[0040] Returning to Figure 4 of the appended drawings the endless track 23 will be described in greater detail.

[0041] As can be seen from Figure 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.

[0042] 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).

[0043] 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.

[0044] 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.

[0045] A second lateral lug 76 is a mirror image of lug 72 about the longitudinal axis.

[0046] The first and second lateral lugs 72 and 76 are laterally spaced apart from the central lug 74.

[0047] 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.

[0048] A first external lug 78 includes two ground-contacting surfaces that are separated by an indentation and are transversally convex.

[0049] 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.

[0050] 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.

[0051] 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 Figure 4. However, it has been found that this type of traction may be detrimental to the steering of the vehicle in some conditions.

[0052] As it is apparent from Figure 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.

[0053] 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.

(0054] The front track assembly 14 is attached to the body 12 of the vehicle 10 in a fashion shown in Figures 4 and 7, while the rear track assembly 16 is attached to the body 12 of the vehicle 10 in a fashion shown in Figure 8 and 9.

[0055] As seen in Figures 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 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.

[0056] 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 Figure 4).

[0057] As seen in Figures 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.

[0058] 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 Figures 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.

(0059] 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.

[0060] 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.

[0061] Figure 10 and Figure 11 show sectional views similar to that of Figure 4 but illustrating variants of an endless track that may be mounted to the track assembly of the present invention.

[0062] In Figure 10, the overall profile of the endless track belt 23a, from one side to the other, i.e. transversely, is generally convex.

[0063] The convex profile of the endless track belt 23a is created by the same lug arrangement as that described hereinabove in relation to Figure 4. In this specific embodiment however, the endless track bell 23a does not include stiffening rods under each row of lugs. Consequently, the rigidity of the endless track belt 23a is less than the rigidity of the endless track belt 23 (Figure 4) and the profile of the endless track belt 23a conforms itself to the profile of the ground. Since the pressure is more localized in the center of the endless track belt 23a, a more punctually localized contact zone between the endless track belt 23a and the ground 29 is created. In many cases, this punctually localized contact zone makes the vehicle 10 more maneuverable.

[0064] Turning now to Figure 11, a third version of an endless track belt 23b will be described. The endless track belt 23b 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 23b, the endless track belt 23b is free to conform itself to the ground 29, as seen in Figure 11. Furthermore, since the pressure is exerted only in the middle of the endless track belt 23b by the wide teeth 40, a punctually localized contact zone between the endless track belt 23b and the ground 29 is created.

[0065] As will be apparent to one skilled in the art, the endless track belts 23a has a particularly punctually localized contact surface with the ground 29. Indeed, since it is transversally convex, it generally contacts the ground with a limited surface at any given time when the ground 29 is hard.

[0066] Furthermore, since there are no guiding rails for the endless track belts 23, 23a or 23b, 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.
These two 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.

[0067] 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.
[0066] 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.

[0069] The endless track structure maintains an adequate configuration over a variety of surfaces.
[0070] 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.
[0071] 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.
[0072] 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.
[0073] 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.
[0074] 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.

Claims

CLAIMS:

1. An endless track for a track assembly providing traction to an all-terrain vehicle (ATV), the track assembly being substitutable to a ground-engaging wheel of the ATV, the track assembly being steerable by changing an orientation of the track assembly by a steering mechanism of the ATV, the track assembly comprising a plurality of wheels, the endless track being mountable around the plurality of wheels, the plurality of wheels including a drive wheel for imparting motion to the endless track, the endless track comprising:
a) an inner surface for facing the plurality of wheels;
b) a ground-engaging outer surface opposite to the inner surface; and c) a plurality of traction projections projecting from the ground-engaging outer surface and spaced apart in a longitudinal direction of the endless track;
the endless track being free of stiffening members extending in a transversal direction of the endless track at locations of respective ones of the traction projections in the longitudinal direction of the endless track.

2. An endless track as defined in claim 1, comprising a plurality of wheel-contacting lugs projecting from the inner surface and arranged to contact the plurality of wheels.

3. An endless track as defined in claim 2, wherein the respective ones of the traction projections register with respective ones of the wheel-contacting lugs in the longitudinal direction of the endless track.

4. An endless track as defined in any one of claims 2 and 3, wherein the plurality of wheel-contacting lugs includes a plurality of drive lugs for engaging the drive wheel.

5. An endless track as defined in any one of claims 2 to 4, wherein the plurality of wheels includes a leading idler wheel and a trailing idler wheel and the plurality of wheel-contacting lugs includes a plurality of guide lugs for contacting the leading idler wheel and the trailing idler wheel.

6. An endless track as defined in any one of claims 2 to 5, wherein the wheel-contacting lugs are equally spaced in the longitudinal direction of the endless track.

7. An endless track as defined in any one of claims 1 to 6, wherein the traction projections are equally spaced in the longitudinal direction of the endless track.

8. An endless track as defined in any one of claims 1 to 7, wherein each traction projection slopes from a central area of the endless track toward lateral end portions of the endless track.

9. An endless track as defined in any one of claims 1 to 8, wherein each traction projection is generally convex in the transversal direction of the endless track.

10. An endless track as defined in any one of claims 1 to 7, wherein each traction projection includes a row of traction lugs spaced apart in the transversal direction of the endless track, the endless track including a central area and a pair of lateral end portions on either side of the central area, the row of traction lugs including at least one traction lug adjacent the central area and having a first projection height and at least one traction lug adjacent one of the lateral end portions and having a second projection height, the first projection height exceeding the second projection height.

11. An endless track as defined in any one of claim 1 to 7, wherein each traction projection has a height that varies in the transversal direction of the endless track.

12. An endless track as defined in claim 4, wherein the plurality of drive lugs is a first row of drive lugs, the plurality of wheel-contacting lugs including a second row of drive lugs projecting from the inner surface for engaging the drive wheel, the first row of drive lugs and the second row of drive lugs being spaced apart in the transversal direction of the endless track, a drive lug of the first row of drive lugs and a drive lug of the second row of drive lugs being configured to simultaneously engage the drive wheel.

13. An endless track as defined in any one of claims 1 to 12, wherein a flexibility of the endless track in the transversal direction of the endless track allows the plurality of wheels to bend the endless track in conformance with a profile of the ground.

14. An endless track as defined in claim 13, wherein the profile of the ground includes a depression and the flexibility of the endless track in the transversal direction of the endless track allows the plurality of wheels to bend the endless track in conformance with the depression.

15. An endless track as defined in claim 14, wherein the endless track includes a central portion aligned with the drive wheel in the transversal direction of the endless track when the drive wheel imparts motion to the endless track, the flexibility of the endless track in the transversal direction of the endless track allowing the central portion of the endless track to contact the depression.

16. An endless track as defined in any one of claims 1 to 15, wherein each traction projection extends from a first lateral edge of the endless track to a second lateral edge of the endless track.

17. An endless track as defined in claim 11, wherein the height of the traction projection is greatest at a point closer to a center of the endless track in the transversal direction of the endless track than to a first lateral edge of the endless track and than to a second lateral edge of the endless track.

18. An endless track as defined in any one of claims 1 to 17, wherein the steering mechanism of the ATV comprises handlebars.

19. An endless track as defined in any one of claims 1 to 17, wherein the ATV comprises a seat that is straddled by a driver of the ATV.

20. A set of endless tracks for a set of track assemblies to provide traction to an all-terrain vehicle (ATV), the set of track assemblies being substitutable to ground-engaging wheels of the ATV, each endless track being as defined in any one of claims 1 to 19.

21. A set of endless tracks as defined in claim 20, wherein the set of endless tracks includes four endless tracks.

22. An all-terrain vehicle (ATV) comprising an endless track as defined in any one of claims 1 to 19.

23. An all-terrain vehicle (ATV) comprising a set of endless tracks as defined in any one of claims 20 and 21.

24. A track assembly for providing traction to an all-terrain vehicle (ATV), the track assembly being substitutable to a ground-engaging wheel of the ATV, the track assembly being steerable by changing an orientation of the track assembly by a steering mechanism of the ATV, the track assembly comprising:
a) a plurality of wheels including:
i. a drive wheel; and ii. a leading idler wheel and a trailing idler wheel spaced apart from the leading idler wheel in a longitudinal direction of the track assembly;
and b) an endless track mounted around the plurality of wheels and comprising:
i. an inner surface for facing the plurality of wheels, the drive wheel being rotatable to impart motion to the endless track;
ii. a ground-engaging outer surface opposite to the inner surface;
and iii. a plurality of traction projections projecting from the ground-engaging outer surface and spaced apart in a longitudinal direction of the endless track;
the endless track being free of stiffening members extending in a transversal direction of the endless track at locations of respective ones of the traction projections in the longitudinal direction of the endless track.

25. A track assembly as defined in claim 24, wherein a segment of the endless track extending between the leading idler wheel and the trailing idler wheel defines a ground-engaging run of the endless track, the ground-engaging run including:
- a load bearing section located between the leading idler wheel and the trailing idler wheel and transferring to the ground a major portion of the load carried by the track assembly;
- a leading section extending between the leading idler wheel and the load bearing section and oriented such as to converge toward the ground when the endless track is in motion and propels the ATV; and - a trailing section extending between the load bearing section and the trailing idler wheel and oriented such as to diverge from the ground when the endless track is in motion and propels the ATV.

26. A track assembly as defined in any one of claims 24 and 25, wherein a horizontal distance between an axis of rotation of the leading idler wheel and an axis of rotation of the drive wheel is different from a horizontal distance between an axis of rotation of the trailing idler wheel and the axis of rotation of the drive wheel.

27. A track assembly as defined in claim 26, comprising a support structure including:
- a center portion rotatably supported at the axis of rotation of the drive wheel;
- a first support arm mounted to the center portion and extending along a radial direction of the drive wheel toward a leading end of the track assembly; and - a second support arm mounted to the center portion and extending along a radial direction of the drive wheel toward a trailing end of the track assembly.

28. A track assembly as defined in claim 27, wherein the first support arm defines a first angle with an imaginary horizontal axis which extends through the axis of rotation of the drive wheel, the second support arm defining a second angle with the imaginary horizontal axis, the first angle being different from the second angle.

29. A track assembly as defined in any one of claims 25 to 28, wherein the drive wheel is in rolling contact with the ground-engaging run.

30. A track assembly as defined in any one of claims 26 to 29, wherein the drive wheel is in overlapping relationship with one of the leading idler wheel and the trailing idler wheel, when viewed in a plane that is normal to the axis of rotation of the drive wheel.

31. A track assembly as defined in claim 30, wherein the drive wheel is in overlapping relationship with the trailing idler wheel, when viewed in a plane normal to the axis of rotation of the drive wheel.

32. A track assembly as defined in any one of claims 25 to 31, wherein the load bearing section is located closer to one of the leading idler wheel and the trailing idler wheel than to the other of the leading idler wheel and the trailing idler wheel.

33. A track assembly as defined in claim 27, wherein one of the first and second support arms is longer than the other of the first and second support arms.

34. A track assembly as defined in claim 27, wherein the first support arm and the second support arm define an obtuse angle therebetween.

35. A track assembly as defined in claim 26, wherein the axis of rotation of the drive wheel is located above the axis of rotation of the leading idler wheel and the axis of rotation of the trailing idler wheel.

36. A track assembly as defined in claim 26, wherein the drive wheel has a periphery bound between a first upper horizontal imaginary plane and a first lower horizontal imaginary plane, one of the leading and trailing idler wheels having a periphery bound between a second upper horizontal imaginary plane and a second lower horizontal imaginary plane, the first lower horizontal imaginary plane being positioned below the second upper horizontal imaginary plane.

37. A track assembly as defined in claim 26, wherein the drive wheel has a periphery bound between a first upper horizontal imaginary plane and a first lower horizontal imaginary plane, the leading idler wheel having a periphery bound between a second upper horizontal imaginary plane and a second lower horizontal imaginary plane, the trailing idler wheel having a periphery bound between a third upper horizontal imaginary plane and a third lower horizontal imaginary plane, the first lower horizontal imaginary plane being positioned below the second upper horizontal imaginary plane and below the third upper horizontal imaginary plane.

38. A track assembly as defined in any one of claims 24 to 37, wherein the plurality of wheels imparts a generally triangular path of travel to the endless track.

39. A track assembly as defined in any one of claims 25 to 37, wherein the plurality of wheels define a track supporting and guiding arrangement that is in rolling contact with the inner surface at a plurality of positions, one of said positions being the load bearing section.

40. A track assembly as defined in any one of claims 25 to 39, wherein the load bearing section extends below the leading section.

41. A track assembly as defined in any one of claims 25 to 40, wherein the load bearing section extends below the trailing section.

42. A track assembly as defined in claim 24, wherein an axis of rotation of the drive wheel is located closer to an axis of rotation of a given one of the leading idler wheel and the trailing idler wheel than to an axis of rotation of the other one of the leading idler wheel and the trailing idler wheel in the longitudinal direction of the track assembly.

43. A track assembly as defined in claim 42, wherein the given one of the leading idler wheel and the trailing idler wheel is the trailing idler wheel.

44. A track assembly as defined in any one of claims 24, 42 and 43, comprising a support structure interconnecting the leading idler wheel and the trailing idler wheel.

45. A track assembly as defined in claim 44, wherein the support structure is pivotable about a pivot axis generally parallel to an axis of rotation of the drive wheel.

46. A track assembly as defined in claim 45, wherein the pivot axis of the support structure is coaxial with the axis of rotation of the drive wheel.

47. A track assembly as defined in any one of claims 44 to 46, wherein the support structure comprises a first arm extending towards the leading idler wheel and a second arm extending towards the trailing idler wheel and shorter than the first arm.

48. A track assembly as defined in claim 47, wherein the first arm and the second arm define an obtuse angle therebetween.

49. A track assembly as defined in any one of claims 24 and 42 to 48, wherein a ground-engaging run of the endless track extends between the leading idler wheel and the trailing idler wheel and includes:
- an intermediate section located between the leading idler and the trailing idler;
- a leading section rising from the intermediate section and extending towards the leading idler wheel; and - a trailing section rising from the intermediate section and extending towards the trailing idler wheel.

50. A track assembly as defined in any one of claims 24 to 49, wherein the endless track comprises a plurality of wheel-contacting lugs projecting from the inner surface and arranged to contact the plurality of wheels.

51. A track assembly as defined in claim 50, wherein the respective ones of the traction projections register with respective ones of the wheel-contacting lugs in the longitudinal direction of the endless track.

52. A track assembly as defined in any one of claims 50 and 51, wherein the plurality of wheel-contacting lugs includes a plurality of drive lugs for engaging the drive wheel.

53. A track assembly as defined in any one of claims 50 to 52, wherein the plurality of wheel-contacting lugs includes a plurality of guide lugs for contacting the leading idler wheel and the trailing idler wheel.

54. A track assembly as defined in any one of claims 50 to 53, wherein the wheel-contacting lugs are equally spaced in the longitudinal direction of the endless track.

55. A track assembly as defined in any one of claims 24 to 54, wherein the traction projections are equally spaced in the longitudinal direction of the endless track.

56. A track assembly as defined in any one of claims 24 to 55, wherein each traction projection slopes from a central area of the endless track toward lateral end portions of the endless track.

57. A track assembly as defined in any one of claims 24 to 56, wherein each traction projection is generally convex in the transversal direction of the endless track.

58. A track assembly as defined in any one of claims 24 to 55, wherein each traction projection includes a row of traction lugs spaced apart in the transversal direction of the endless track, the endless track including a central area and a pair of lateral end portions on either side of the central area, the row of traction lugs including at least one traction lug adjacent the central area and having a first projection height and at least one traction lug adjacent one of the lateral end portions and having a second projection height, the first projection height exceeding the second projection height.

59. A track assembly as defined in any one of claim 24 to 55, wherein each traction projection has a height that varies in the transversal direction of the endless track.

60. A track assembly as defined in claim 52, wherein the plurality of drive lugs is a first row of drive lugs, the plurality of wheel-contacting lugs including a second row of drive lugs projecting from the inner surface for engaging the drive wheel, the second row of drive lugs being spaced apart from the first row of drive lugs in the transversal direction of the endless track, a drive lug of the first row of drive lugs and a drive lug of the second row of drive lugs being configured to simultaneously engage the drive wheel.

61. A track assembly as defined in any one of claims 24 to 60, wherein a flexibility of the endless track in the transversal direction of the endless track allows the plurality of wheels to bend the endless track in conformance with a profile of the ground.

62. A track assembly as defined in claim 61, wherein the profile of the ground includes a depression and the flexibility of the endless track in the transversal direction of the endless track allows the plurality of wheels to bend the endless track in conformance with the depression.

63. A track assembly as defined in claim 62, wherein the endless track includes a central portion aligned with the drive wheel in the transversal direction of the endless track when the drive wheel imparts motion to the endless track, the flexibility of the endless track in the transversal direction of the endless track allowing the central portion of the endless track to contact the depression.

64. A track assembly as defined in any one of claims 24 to 63, wherein each traction projection extends from a first lateral edge of the endless track to a second lateral edge of the endless track.

65. A track assembly as defined in claim 59, wherein the height of the traction projection is greatest at a point closer to a center of the endless track in the transversal direction of the endless track than to a first lateral edge of the endless track and than to a second lateral edge of the endless track.

66. A track assembly as defined in any one of claims 24 to 65, wherein the steering mechanism of the ATV comprises handlebars.

67. A track assembly as defined in any one of claims 24 to 66, wherein the ATV comprises a seat that is straddled by a driver of the ATV.

68. A set of track assemblies for providing traction to an all-terrain vehicle (ATV), the set of track assemblies being substitutable to ground-engaging wheels of the ATV, each track assembly being as defined in any one of claims 24 to 67.

69. A set of track assemblies as defined in claim 68, wherein the set of track assemblies includes four track assemblies.

70. An all-terrain vehicle (ATV) comprising a track assembly as defined in any one of claims 24 to 67.

71. An all-terrain vehicle (ATV) comprising a set of track assemblies as defined in any one of claims 68 and 69.

72. An endless track for a track assembly providing traction to an all-terrain vehicle (ATV), the track assembly being substitutable to a ground-engaging wheel of the ATV, the track assembly being steerable by changing an orientation of the track assembly by a steering mechanism of the ATV, the track assembly comprising a plurality of wheels, the endless track being mountable around the plurality of wheels, the plurality of wheels including a drive wheel for imparting motion to the endless track, the endless track comprising:
a) an inner surface for facing the plurality of wheels;
b) a ground-engaging outer surface opposite to the inner surface;
c) a plurality of wheel-contacting lugs projecting from the inner surface to contact the plurality of wheels; and d) a plurality of traction projections projecting from the ground-engaging outer surface and spaced apart in a longitudinal direction of the endless track;
the endless track being free of stiffening members extending in a transversal direction of the endless track at locations of respective ones of the wheel-contacting lugs in the longitudinal direction of the endless track.

73. An endless track as defined in claim 72, wherein the respective ones of the wheel-contacting lugs register with respective ones of the traction projections in the longitudinal direction of the endless track.

74. An endless track as defined in any one of claims 72 and 73, wherein the plurality of wheel-contacting lugs includes a plurality of drive lugs for engaging the drive wheel.

75. An endless track as defined in any one of claims 72 to 74, wherein the plurality of wheels includes a leading idler wheel and a trailing idler wheel and the plurality of wheel-contacting lugs includes a plurality of guide lugs for contacting the leading idler wheel and the trailing idler wheel.

76. An endless track as defined in any one of claims 72 to 75, wherein the wheel-contacting lugs are equally spaced in the longitudinal direction of the endless track.

77. An endless track as defined in any one of claims 72 to 76, wherein the traction projections are equally spaced in the longitudinal direction of the endless track.

78. An endless track as defined in any one of claims 72 to 77, wherein each traction projection slopes from a central area of the endless track toward lateral end portions of the endless track.

79. An endless track as defined in any one of claims 72 to 78, wherein each traction projection is generally convex in the transversal direction of the endless track.

80. An endless track as defined in any one of claims 72 to 77, wherein each traction projection includes a row of traction lugs spaced apart in the transversal direction of the endless track, the endless track including a central area and a pair of lateral end portions on either side of the central area, the row of traction lugs including at least one traction lug adjacent the central area and having a first projection height and at least one traction lug adjacent one of the lateral end portions and having a second projection height, the first projection height exceeding the second projection height.

81. An endless track as defined in any one of claim 72 to 77, wherein each traction projection has a height that varies in the transversal direction of the endless track.

82. An endless track as defined in claim 74, wherein the plurality of drive lugs is a first row of drive lugs, the plurality of wheel-contacting lugs including a second row of drive lugs projecting from the inner surface for engaging the drive wheel, the first row of drive lugs and the second row of drive lugs being spaced apart in the transversal direction of the endless track, a drive lug of the first row of drive lugs and a drive lug of the second row of drive lugs being configured to simultaneously engage the drive wheel.

83. An endless track as defined in any one of claims 72 to 82, wherein a flexibility of the endless track in the transversal direction of the endless track allows the plurality of wheels to bend the endless track in conformance with a profile of the ground.

84. An endless track as defined in claim 83, wherein the profile of the ground includes a depression and the flexibility of the endless track in the transversal direction of the endless track allows the plurality of wheels to bend the endless track in conformance with the depression.

85. An endless track as defined in claim 84, wherein the endless track includes a central portion aligned with the drive wheel in the transversal direction of the endless track when the drive wheel imparts motion to the endless track, the flexibility of the endless track in the transversal direction of the endless track allowing the central portion of the endless track to contact the depression.

86. An endless track as defined in any one of claims 72 to 85, wherein each traction projection extends from a first lateral edge of the endless track to a second lateral edge of the endless track.

87. An endless track as defined in claim 86, wherein the height of the traction projection is greatest at a point closer to a center of the endless track in the transversal direction of the endless track than to a first lateral edge of the endless track and than to a second lateral edge of the endless track.

88. An endless track as defined in any one of claims 72 to 87, wherein the steering mechanism of the ATV comprises handlebars.

89. An endless track as defined in any one of claims 72 to 88, wherein the ATV comprises a seat that is straddled by a driver of the ATV.

90. A set of endless tracks for a set of track assemblies to provide traction to an all-terrain vehicle (ATV), the set of track assemblies being substitutable to ground-engaging wheels of the ATV, each endless track being as defined in any one of claims 72 to 89.

91. A set of endless tracks as defined in claim 90, wherein the set of endless tracks includes four endless tracks.

92. An all-terrain vehicle (ATV) comprising an endless track as defined in any one of claims 72 to 89.

93. An all-terrain vehicle (ATV) comprising a set of endless tracks as defined in any one of claims 90 and 91.

94. A track assembly for providing traction to an all-terrain vehicle (ATV), the track assembly being substitutable to a ground-engaging wheel of the ATV, the track assembly being steerable by changing an orientation of the track assembly by a steering mechanism of the ATV, the track assembly comprising:
a) a plurality of wheels including:
i. a drive wheel; and ii. a leading idler wheel and a trailing idler wheel spaced apart from the leading idler wheel in a longitudinal direction of the track assembly;
and b) an endless track mounted around the plurality of wheels and comprising:
i. an inner surface for facing the plurality of wheels, the drive wheel being rotatable to impart motion to the endless track;
ii. a ground-engaging outer surface opposite to the inner surface;
iii. a plurality of wheel-contacting lugs projecting from the inner surface to contact the plurality of wheels; and iv. a plurality of traction projections projecting from the ground-engaging outer surface and spaced apart in a longitudinal direction of the endless track;
the endless track being free of stiffening members extending in a transversal direction of the endless track at locations of respective ones of the wheel-contacting lugs in the longitudinal direction of the endless track.

95. A track assembly as defined in claim 94, wherein a segment of the endless track extending between the leading idler wheel and the trailing idler wheel defines a ground-engaging run of the endless track, the ground-engaging run including:
- a load bearing section located between the leading idler wheel and the trailing idler wheel and transferring to the ground a major portion of the load carried by the track assembly;
- a leading section extending between the leading idler wheel and the load bearing section and oriented such as to converge toward the ground when the endless track is in motion and propels the ATV; and - a trailing section extending between the load bearing section and the trailing idler wheel and oriented such as to diverge from the ground when the endless track is in motion and propels the ATV.

96. A track assembly as defined in any one of claims 94 and 95, wherein a horizontal distance between an axis of rotation of the leading idler wheel and an axis of rotation of the drive wheel is different from a horizontal distance between an axis of rotation of the trailing idler wheel and the axis of rotation of the drive wheel.

97. A track assembly as defined in claim 96, comprising a support structure including:
- a center portion rotatably supported at the axis of rotation of the drive wheel;
- a first support arm mounted to the center portion and extending along a radial direction of the drive wheel toward a leading end of the track assembly; and - a second support arm mounted to the center portion and extending along a radial direction of the drive wheel toward a trailing end of the track assembly.

98. A track assembly as defined in claim 97, wherein the first support arm defines a first angle with an imaginary horizontal axis which extends through the axis of rotation of the drive wheel, the second support arm defining a second angle with the imaginary horizontal axis, the first angle being different from the second angle.

99. A track assembly as defined in any one of claims 95 to 98, wherein the drive wheel is in rolling contact with the ground-engaging run.

100. A track assembly as defined in any one of claims 96 to 99, wherein the drive wheel is in overlapping relationship with one of the leading idler wheel and the trailing idler wheel, when viewed in a plane that is normal to the axis of rotation of the drive wheel.

101. A track assembly as defined in claim 100, wherein the drive wheel is in overlapping relationship with the trailing idler wheel, when viewed in a plane normal to the axis of rotation of the drive wheel.

102. A track assembly as defined in any one of claims 95 to 101, wherein the load bearing section is located closer to one of the leading idler wheel and the trailing idler wheel than to the other of the leading idler wheel and the trailing idler wheel.

103. A track assembly as defined in claim 97, wherein one of the first and second support arms is longer than the other of the first and second support arms.

104. A track assembly as defined in claim 97, wherein the first support arm and the second support arm define an obtuse angle therebetween.

105. A track assembly as defined in claim 96, wherein the axis of rotation of the drive wheel is located above the axis of rotation of the leading idler wheel and the axis of rotation of the trailing idler wheel.

106. A track assembly as defined in claim 94, wherein the drive wheel has a periphery bound between a first upper horizontal imaginary plane and a first lower horizontal imaginary plane, one of the leading and trailing idler wheels having a periphery bound between a second upper horizontal imaginary plane and a second lower horizontal imaginary plane, the first lower horizontal imaginary plane being positioned below the second upper horizontal imaginary plane.

107. A track assembly as defined in claim 94, wherein the drive wheel has a periphery bound between a first upper horizontal imaginary plane and a first lower horizontal imaginary plane, the leading idler wheel having a periphery bound between a second upper horizontal imaginary plane and a second lower horizontal imaginary plane, the trailing idler wheel having a periphery bound between a third upper horizontal imaginary plane and a third lower horizontal imaginary plane, the first lower horizontal imaginary plane being positioned below the second upper horizontal imaginary plane and below the third upper horizontal imaginary plane.

108. A track assembly as defined in any one of claims 94 to 107, wherein the plurality of wheels imparts a generally triangular path of travel to the endless track.

109. A track assembly as defined in any one of claims 95 to 108, wherein the plurality of wheels define a track supporting and guiding arrangement that is in rolling contact with the inner surface at a plurality of positions, one of said positions being the load bearing section.

110. A track assembly as defined in any one of claims 95 to 109, wherein the load bearing section extends below the leading section.

111. A track assembly as defined in any one of claims 95 to 110, wherein the load bearing section extends below the trailing section.

112. A track assembly as defined in claim 94, wherein an axis of rotation of the drive wheel is located closer to an axis of rotation of a given one of the leading idler wheel and the trailing idler wheel than to an axis of rotation of the other one of the leading idler wheel and the trailing idler wheel in the longitudinal direction of the track assembly.

113. A track assembly as defined in claim 112, wherein the given one of the leading idler wheel and the trailing idler wheel is the trailing idler wheel.

114. A track assembly as defined in any one of claims 94, 112 and 113, comprising a support structure interconnecting the leading idler wheel and the trailing idler wheel.

115. A track assembly as defined in claim 114, wherein the support structure is pivotable about a pivot axis generally parallel to an axis of rotation of the drive wheel.

116. A track assembly as defined in claim 115, wherein the pivot axis of the support structure is coaxial with the axis of rotation of the drive wheel.

117. A track assembly as defined in any one of claims 114 to 116, wherein the support structure comprises a first arm extending towards the leading idler wheel and a second arm extending towards the trailing idler wheel and shorter than the first arm.

118. A track assembly as defined in claim 117, wherein the first arm and the second arm define an obtuse angle therebetween.

119. A track assembly as defined in any one of claims 94 and 112 to 118, wherein a ground-engaging run of the endless track extends between the leading idler wheel and the trailing idler wheel and includes:
- an intermediate section located between the leading idler and the trailing idler;
- a leading section rising from the intermediate section and extending towards the leading idler wheel; and - a trailing section rising from the intermediate section and extending towards the trailing idler wheel.

120. A track assembly as defined in any one of claims 94 to 119, wherein the respective ones of the wheel-contacting lugs register with respective ones of the traction projections in the longitudinal direction of the endless track.

121. A track assembly as defined in any one of claims 94 to 120, wherein the plurality of wheel-contacting lugs includes a plurality of drive lugs for engaging the drive wheel.

122. A track assembly as defined in any one of claims 94 to 121, wherein the plurality of wheel-contacting lugs includes a plurality of guide lugs for contacting the leading idler wheel and the trailing idler wheel.

123. A track assembly as defined in any one of claims 94 to 122, wherein the wheel-contacting lugs are equally spaced in the longitudinal direction of the endless track.

124. A track assembly as defined in any one of claims 94 to 123, wherein the traction projections are equally spaced in the longitudinal direction of the endless track.

125. A track assembly as defined in any one of claims 94 to 124, wherein each traction projection slopes from a central area of the endless track toward lateral end portions of the endless track.

126. A track assembly as defined in any one of claims 94 to 125, wherein each traction projection is generally convex in the transversal direction of the endless track.

127. A track assembly as defined in any one of claims 94 to 124, wherein each traction projection includes a row of traction lugs spaced apart in the transversal direction of the endless track, the endless track including a central area and a pair of lateral end portions on either side of the central area, the row of traction lugs including at least one traction lug adjacent the central area and having a first projection height and at least one traction lug adjacent one of the lateral end portions and having a second projection height, the first projection height exceeding the second projection height.

128. A track assembly as defined in any one of claim 94 to 124, wherein each traction projection has a height that varies in the transversal direction of the endless track.

129. A track assembly as defined in claim 121, wherein the plurality of drive lugs is a first row of drive lugs, the plurality of wheel-contacting lugs including a second row of drive lugs projecting from the inner surface for engaging the drive wheel, the first row of drive lugs and the second row of drive lugs being spaced apart in the transversal direction of the endless track, a drive lug of the first row of drive lugs and a drive lug of the second row of drive lugs being configured to simultaneously engage the drive wheel.

130. A track assembly as defined in any one of claims 94 to 129, wherein a flexibility of the endless track in the transversal direction of the endless track allows the plurality of wheels to bend the endless track in conformance with a profile of the ground.

131. A track assembly as defined in claim 130, wherein the profile of the ground includes a depression and the flexibility of the endless track in the transversal direction of the endless track allows the plurality of wheels to bend the endless track in conformance with the depression.

132. A track assembly as defined in claim 131, wherein the endless track includes a central portion aligned with the drive wheel in the transversal direction of the endless track when the drive wheel imparts motion to the endless track, the flexibility of the endless track in the transversal direction of the endless track allowing the central portion of the endless track to contact the depression.

133. A track assembly as defined in any one of claims 94 to 132, wherein each traction projection extends from a first lateral edge of the endless track to a second lateral edge of the endless track.

134. A track assembly as defined in claim 128, wherein the height of the traction projection is greatest at a point closer to a center of the endless track in the transversal direction of the endless track than to a first lateral edge of the endless track and than to a second lateral edge of the endless track.

135. A track assembly as defined in any one of claims 94 to 134, wherein the steering mechanism of the ATV comprises handlebars.

136. A track assembly as defined in any one of claims 94 to 135, wherein the ATV comprises a seat that is straddled by a driver of the ATV.

137. A set of track assemblies for providing traction to an all-terrain vehicle (ATV), the set of track assemblies being substitutable to ground-engaging wheels of the ATV, each track assembly being as defined in any one of claims 94 to 136.

138. A set of track assemblies as defined in claim 137, wherein the set of track assemblies includes four track assemblies.

139. An all-terrain vehicle (ATV) comprising a track assembly as defined in any one of claims 94 to 136.

140. An all-terrain vehicle (ATV) comprising a set of track assemblies as defined in any one of claims 137 and 138.

141. An endless track for a reduced-size vehicle designed primarily for off-highway usage, over undeveloped roads or other unprepared surfaces, the endless track being steerable by changing an orientation of the endless track by a steering mechanism of the vehicle, the endless track comprising flexible material to flex around a plurality of wheels, the plurality of wheels including a drive wheel for imparting motion to the endless track, the endless track comprising:
- a ground-engaging outer surface:
- an inner surface opposite to the ground-engaging outer surface; and - a plurality of traction projections projecting from the ground-engaging outer surface and distributed in a longitudinal direction of the track;
the endless track being free of stiffening inserts extending in a transversal direction of the endless track and disposed within the flexible material at locations of respective ones of the traction projections in the longitudinal direction of the endless track.

142. An endless track as defined in claim 141, comprising a plurality of wheel-contacting lugs projecting from the inner surface and arranged to contact the plurality of wheels.

143. An endless track as defined in claim 142, wherein the respective ones of the traction projections register with respective ones of the wheel-contacting lugs in the longitudinal direction of the endless track.

144. An endless track as defined in any one of claims 142 and 143, wherein the plurality of wheel-contacting lugs includes a plurality of drive lugs for engaging the drive wheel.

145. An endless track as defined in any one of claims 142 to 144, wherein the plurality of wheels includes a leading idler wheel and a trailing idler wheel and the plurality of wheel-contacting lugs includes a plurality of guide lugs for contacting the leading idler wheel and the trailing idler wheel.

146. An endless track as defined in any one of claims 142 to 145, wherein the wheel-contacting lugs are equally spaced in the longitudinal direction of the endless track.

147. An endless track as defined in any one of claims 141 to 146, wherein the traction projections are equally spaced in the longitudinal direction of the endless track.

148. An endless track as defined in any one of claims 141 to 147, wherein each traction projection slopes from a central area of the endless track toward lateral end portions of the endless track.

149. An endless track as defined in any one of claims 141 to 148, wherein each traction projection is generally convex in the transversal direction of the endless track.

150. An endless track as defined in any one of claims 141 to 148, wherein each traction projection includes a row of traction lugs spaced apart in the transversal direction of the endless track, the endless track including a central area and a pair of lateral end portions on either side of the central area, the row of traction lugs including at least one traction lug adjacent the central area and having a first projection height and at least one traction lug adjacent one of the lateral end portions and having a second projection height, the first projection height exceeding the second projection height.

151. An endless track as defined in any one of claim 141 to 148, wherein each traction projection has a height that varies in the transversal direction of the endless track.

152. An endless track as defined in claim 144, wherein the plurality of drive lugs is a first row of drive lugs, the plurality of wheel-contacting lugs including a second row of drive lugs projecting from the inner surface for engaging the drive wheel, the first row of drive lugs and the second row of drive lugs being spaced apart in the transversal direction of the endless track, a drive lug of the first row of drive lugs and a drive lug of the second row of drive lugs being configured to simultaneously engage the drive wheel.

153. An endless track as defined in any one of claims 141 to 152, wherein a flexibility of the endless track in the transversal direction of the endless track allows the plurality of wheels to bend the endless track in conformance with a profile of the ground.

154. An endless track as defined in claim 153, wherein the profile of the ground includes a depression and the flexibility of the endless track in the transversal direction of the endless track allows the plurality of wheels to bend the endless track in conformance with the depression.

155. An endless track as defined in claim 154, wherein the endless track includes a central portion aligned with the drive wheel in the transversal direction of the endless track when the drive wheel imparts motion to the endless track, the flexibility of the endless track in the transversal direction of the endless track allowing the central portion of the endless track to contact the depression.

156. An endless track as defined in any one of claims 141 to 155, wherein each traction projection extends from a first lateral edge of the endless track to a second lateral edge of the endless track.

157. An endless track as defined in claim 151, wherein the height of the traction projection is greatest at a point closer to a center of the endless track in the transversal direction of the endless track than to a first lateral edge of the endless track and than to a second lateral edge of the endless track.

158. An endless track as defined in any one of claims 141 to 157, wherein the vehicle is an all-terrain vehicle (ATV).

159. An endless track as defined in any one of claims 141 to 158, wherein the steering mechanism of the vehicle comprises handlebars.

160. An endless track as defined in any one of claims 141 to 159, wherein the vehicle comprises a seat that is straddled by a driver of the vehicle.

161. A set of endless tracks for a reduced-size vehicle designed primarily for off-highway usage, over undeveloped roads or other unprepared surfaces, each endless track of the set of endless tracks being as defined in any one of claims 141 to 160.

162. A set of endless tracks as defined in claim 161, wherein the set of endless tracks includes four endless tracks.

163. A reduced-size vehicle designed primarily for off-highway usage, over undeveloped roads or other unprepared surfaces, the vehicle comprising an endless track as defined in any one of claims 141 to 160.

164. A reduced-size vehicle designed primarily for off-highway usage, over undeveloped roads or other unprepared surfaces, the vehicle comprising a set of endless tracks as defined in any one of claims 161 and 162.

165. A reduced-size vehicle as defined in any one of claims 163 and 164, wherein the vehicle is an all-terrain vehicle (ATV).

166. A reduced-size vehicle as defined in any one of claims 163 to 165, wherein the steering mechanism of the vehicle comprises handlebars.

167. A reduced-size vehicle as defined in any one of claims 163 to 166, wherein the vehicle includes a seat that is straddled by a driver of the vehicle.

168. A track assembly for a reduced-size vehicle designed primarily for off-highway usage, over undeveloped roads or other unprepared surfaces, the track assembly being steerable by changing an orientation of the track assembly by a steering mechanism of the vehicle, the track assembly comprising:
a) a plurality of wheels including:
i. a drive wheel; and ii. a leading idler wheel and a trailing idler wheel spaced apart from one another in a longitudinal direction of the track assembly;
and b) an endless track mounted around the plurality of wheels, the endless track comprising flexible material to flex around the plurality of wheels, the endless track comprising:

i. an inner surface for facing the plurality of wheels, the drive wheel being rotatable to impart motion to the endless track;
ii. a ground-engaging outer surface opposite to the inner surface;
and iii. a plurality of traction projections projecting from the ground-engaging outer surface and spaced apart in a longitudinal direction of the endless track;
the endless track being free of stiffening inserts extending in a transversal direction of the endless track and disposed within the flexible material at locations of respective ones of the traction projections in the longitudinal direction of the endless track.

169. A track assembly as defined in claim 168, wherein a segment of the endless track extending between the leading idler wheel and the trailing idler wheel defines a ground-engaging run of the endless track, the ground-engaging run including:
- a load bearing section located between the leading idler wheel and the trailing idler wheel and transferring to the ground a major portion of the load carried by the track assembly;
- a leading section extending between the leading idler wheel and the load bearing section and oriented such as to converge toward the ground when the endless track is in motion and propels the vehicle;
and - a trailing section extending between the load bearing section and the trailing idler wheel and oriented such as to diverge from the ground when the endless track is in motion and propels the vehicle.

170. A track assembly as defined in any one of claims 168 and 169, wherein a horizontal distance between an axis of rotation of the leading idler wheel and an axis of rotation of the drive wheel is different from a horizontal distance between an axis of rotation of the trailing idler wheel and the axis of rotation of the drive wheel.

171. A track assembly as defined in claim 170, comprising a support structure including:
- a center portion rotatably supported at the axis of rotation of the drive wheel;
- a first support arm mounted to the center portion and extending along a radial direction of the drive wheel toward a leading end of the track assembly; and - a second support arm mounted to the center portion and extending along a radial direction of the drive wheel toward a trailing end of the track assembly.

172. A track assembly as defined in claim 171, wherein the first support arm defines a first angle with an imaginary horizontal axis which extends through the axis of rotation of the drive wheel, the second support arm defining a second angle with the imaginary horizontal axis, the first angle being different from the second angle.

173. A track assembly as defined in any one of claims 169 to 172, wherein the drive wheel is in rolling contact with the ground-engaging run.

174. A track assembly as defined in any one of claims 170 to 173, wherein the drive wheel is in overlapping relationship with one of the leading idler wheel and the trailing idler wheel, when viewed in a plane that is normal to the axis of rotation of the drive wheel.

175. A track assembly as defined in claim 174, wherein the drive wheel is in overlapping relationship with the trailing idler wheel, when viewed in a plane normal to the axis of rotation of the drive wheel.

176. A track assembly as defined in any one of claims 169 to 175, wherein the load bearing section is located closer to one of the leading idler wheel and the trailing idler wheel than to the other of the leading idler wheel and the trailing idler wheel.

177. A track assembly as defined in claim 171, wherein one of the first and second support arms is longer than the other of the first and second support arms.

178. A track assembly as defined in claim 177, wherein the first support arm and the second support arm define an obtuse angle therebetween.

179. A track assembly as defined in claim 170, wherein the axis of rotation of the drive wheel is located above the axis of rotation of the leading idler wheel and the axis of rotation of the trailing idler wheel.

180. A track assembly as defined in claim 168, wherein the drive wheel has a periphery bound between a first upper horizontal imaginary plane and a first lower horizontal imaginary plane, one of the leading and trailing idler wheels having a periphery bound between a second upper horizontal imaginary plane and a second lower horizontal imaginary plane, the first lower horizontal imaginary plane being positioned below the second upper horizontal imaginary plane.

181. A track assembly as defined in claim 168, wherein the drive wheel has a periphery bound between a first upper horizontal imaginary plane and a first lower horizontal imaginary plane, the leading idler wheel having a periphery bound between a second upper horizontal imaginary plane and a second lower horizontal imaginary plane, the trailing idler wheel having a periphery bound between a third upper horizontal imaginary plane and a third lower horizontal imaginary plane, the first lower horizontal imaginary plane being positioned below the second upper horizontal imaginary plane and below the third upper horizontal imaginary plane.

182. A track assembly as defined in any one of claims 168 to 181, wherein the plurality of wheels imparts a generally triangular path of travel to the endless track.

183. A track assembly as defined in any one of claims 169 to 182, wherein the plurality of wheels define a track supporting and guiding arrangement that is in rolling contact with the inner surface at a plurality of positions, one of said positions being the load bearing section.

184. A track assembly as defined in any one of claims 169 to 183, wherein the load bearing section extends below the leading section.

185. A track assembly as defined in any one of claims 169 to 183, wherein the load bearing section extends below the trailing section.

186. A track assembly as defined in claim 168, wherein an axis of rotation of the drive wheel is located closer to an axis of rotation of a given one of the leading idler wheel and the trailing idler wheel than to an axis of rotation of the other one of the leading idler wheel and the trailing idler wheel in the longitudinal direction of the track assembly.

187. A track assembly as defined in claim 186, wherein the given one of the leading idler wheel and the trailing idler wheel is the trailing idler wheel.

188. A track assembly as defined in any one of claims 168, 186 and 187, comprising a support structure interconnecting the leading idler wheel and the trailing idler wheel.

189. A track assembly as defined in claim 188, wherein the support structure is pivotable about a pivot axis generally parallel to an axis of rotation of the drive wheel.

190. A track assembly as defined in claim 189, wherein the pivot axis of the support structure is coaxial with the axis of rotation of the drive wheel.

191. A track assembly as defined in any one of claims 188 to 190, wherein the support structure comprises a first arm extending towards the leading idler wheel and a second arm extending towards the trailing idler wheel and shorter than the first arm.

192. A track assembly as defined in claim 191, wherein the first arm and the second arm define an obtuse angle therebetween.

193. A track assembly as defined in any one of claims 168 and 186 to 192, wherein a ground-engaging run of the endless track extends between the leading idler wheel and the trailing idler wheel and includes:
- an intermediate section located between the leading idler and the trailing idler;
- a leading section rising from the intermediate section and extending towards the leading idler wheel; and - a trailing section rising from the intermediate section and extending towards the trailing idler wheel.

194. A track assembly as defined in any one of claims 168 to 193, wherein the endless track comprises a plurality of wheel-contacting lugs projecting from the inner surface and arranged to contact the plurality of wheels.

195. A track assembly as defined in claim 194, wherein the respective ones of the traction projections register with respective ones of the wheel-contacting lugs in the longitudinal direction of the endless track.

196. A track assembly as defined in any one of claims 194 and 195, wherein the plurality of wheel-contacting lugs includes a plurality of drive lugs for engaging the drive wheel.

197. A track assembly as defined in any one of claims 194 to 196, wherein the plurality of wheel-contacting lugs includes a plurality of guide lugs for contacting the leading idler wheel and the trailing idler wheel.

198. A track assembly as defined in any one of claims 194 to 197, wherein the wheel-contacting lugs are equally spaced in the longitudinal direction of the endless track.

199. A track assembly as defined in any one of claims 168 to 198, wherein the traction projections are equally spaced in the longitudinal direction of the endless track.

200. A track assembly as defined in any one of claims 168 to 199, wherein each traction projection slopes from a central area of the endless track toward lateral end portions of the endless track.

201. A track assembly as defined in any one of claims 168 to 200, wherein each traction projection is generally convex in the transversal direction of the endless track.

202. A track assembly as defined in any one of claims 168 to 201, wherein each traction projection includes a row of traction lugs spaced apart in the transversal direction of the endless track, the endless track including a central area and a pair of lateral end portions on either side of the central area, the row of traction lugs including at least one traction lug adjacent the central area and having a first projection height and at least one traction lug adjacent one of the lateral end portions and having a second projection height, the first projection height exceeding the second projection height.

203. A track assembly as defined in any one of claim 168 to 199, wherein each traction projection has a height that varies in the transversal direction of the endless track.

204. A track assembly as defined in claim 196, wherein the plurality of drive lugs is a first row of drive lugs, the plurality of wheel-contacting lugs including a second row of drive lugs projecting from the inner surface for engaging the drive wheel, the second row of drive lugs being spaced apart from the first row of drive lugs in the transversal direction of the endless track, a drive lug of the first row of drive lugs and a drive lug of the second row of drive lugs being configured to simultaneously engage the drive wheel.

205. A track assembly as defined in any one of claims 168 to 204, wherein a flexibility of the endless track in the transversal direction of the endless track allows the plurality of wheels to bend the endless track in conformance with a profile of the ground.

206. A track assembly as defined in claim 205, wherein the profile of the ground includes a depression and the flexibility of the endless track in the transversal direction of the endless track allows the plurality of wheels to bend the endless track in conformance with the depression.

207. A track assembly as defined in claim 206, wherein the endless track includes a central portion aligned with the drive wheel in the transversal direction of the endless track when the drive wheel imparts motion to the endless track, the flexibility of the endless track in the transversal direction of the endless track allowing the central portion of the endless track to contact the depression.

208. A track assembly as defined in any one of claims 168 to 207, wherein each traction projection extends from a first lateral edge of the endless track to a second lateral edge of the endless track.

209. A track assembly as defined in claim 203, wherein the height of the traction projection is greatest at a point closer to a center of the endless track in the transversal direction of the endless track than to a first lateral edge of the endless track and than to a second lateral edge of the endless track.

210. A track assembly as defined in any one of claims 168 to 209, wherein the vehicle is an all-terrain vehicle (ATV).

211. A track assembly as defined in any one of claims 168 to 210, wherein the steering mechanism of the vehicle comprises handlebars.

212. A track assembly as defined in any one of claims 168 to 211, wherein the vehicle comprises a seat that is straddled by a driver of the vehicle.

213. A set of track assemblies for a reduced-size vehicle designed primarily for off-highway usage, over undeveloped roads or other unprepared surfaces, each track assembly of the set of track assemblies being as defined in any one of claims 168 to 212.

214. A set of track assemblies as defined in claim 213, wherein the set of track assemblies includes four track assemblies.

215. A reduced-size vehicle designed primarily for off-highway usage, over undeveloped roads or other unprepared surfaces, the vehicle comprising a track assembly as defined in any one of claims 168 to 209.

216. A reduced-size vehicle designed primarily for off-highway usage, over undeveloped roads or other unprepared surfaces, the vehicle comprising a set of track assemblies as defined in any one of claims 213 and 214.

217. A reduced-size vehicle as defined in any one of claims 215 and 216, wherein the vehicle is an all-terrain vehicle (ATV).

218. A reduced-size vehicle as defined in any one of claims 215 to 217, wherein the steering mechanism of the vehicle comprises handlebars.

219. A reduced-size vehicle as defined in any one of claims 215 to 218, wherein the vehicle includes a seat that is straddled by a driver of the vehicle.

220. An endless track for a reduced-size vehicle designed primarily for off-highway usage, over undeveloped roads or other unprepared surfaces, the endless track being steerable by changing an orientation of the endless track by a steering mechanism of the vehicle, the endless track comprising flexible material to flex around a plurality of wheels, the plurality of wheels including a drive wheel for imparting motion to the endless track, the endless track comprising:
- a ground-engaging outer surface:
- an inner surface opposite to the ground-engaging outer surface;
- a plurality of wheel-contacting lugs projecting from the inner surface to contact the plurality of wheels; and - a plurality of traction projections projecting from the ground-engaging outer surface and distributed in a longitudinal direction of the track;
the endless track being free of stiffening inserts extending in a transversal direction of the endless track and disposed within the flexible material at locations of respective ones of the wheel-contacting lugs in the longitudinal direction of the endless track.

221. An endless track as defined in claim 220, wherein the respective ones of the wheel-contacting lugs register with respective ones of the traction projections in the longitudinal direction of the endless track.

222. An endless track as defined in any one of claims 220 and 221, wherein the plurality of wheel-contacting lugs includes a plurality of drive lugs for engaging the drive wheel.

223. An endless track as defined in any one of claims 220 to 222, wherein the plurality of wheels includes a leading idler wheel and a trailing idler wheel and the plurality of wheel-contacting lugs includes a plurality of guide lugs for contacting the leading idler wheel and the trailing idler wheel.

224. An endless track as defined in any one of claims 220 to 223, wherein the wheel-contacting lugs are equally spaced in the longitudinal direction of the endless track.

225. An endless track as defined in any one of claims 220 to 224, wherein the traction projections are equally spaced in the longitudinal direction of the endless track.

226. An endless track as defined in any one of claims 220 to 225, wherein each traction projection slopes from a central area of the endless track toward lateral end portions of the endless track.

227. An endless track as defined in any one of claims 220 to 226, wherein each traction projection is generally convex in the transversal direction of the endless track.

228. An endless track as defined in any one of claims 220 to 227, wherein each traction projection includes a row of traction lugs spaced apart in the transversal direction of the endless track, the endless track including a central area and a pair of lateral end portions on either side of the central area, the row of traction lugs including at least one traction lug adjacent the central area and having a first projection height and at least one traction lug adjacent one of the lateral end portions and having a second projection height, the first projection height exceeding the second projection height.

229. An endless track as defined in any one of claim 220 to 228, wherein each traction projection has a height that varies in the transversal direction of the endless track.

230. An endless track as defined in claim 222, wherein the plurality of drive lugs is a first row of drive lugs, the plurality of wheel-contacting lugs including a second row of drive lugs projecting from the inner surface for engaging the drive wheel, the first row of drive lugs and the second row of drive lugs being spaced apart in the transversal direction of the endless track, a drive lug of the first row of drive lugs and a drive lug of the second row of drive lugs being configured to simultaneously engage the drive wheel.

231. An endless track as defined in any one of claims 220 to 230, wherein a flexibility of the endless track in the transversal direction of the endless track allows the plurality of wheels to bend the endless track in conformance with a profile of the ground.

232. An endless track as defined in claim 231, wherein the profile of the ground includes a depression and the flexibility of the endless track in the transversal direction of the endless track allows the plurality of wheels to bend the endless track in conformance with the depression.

233. An endless track as defined in claim 232, wherein the endless track includes a central portion aligned with the drive wheel in the transversal direction of the endless track when the drive wheel imparts motion to the endless track, the flexibility of the endless track in the transversal direction of the endless track allowing the central portion of the endless track to contact the depression.

234. An endless track as defined in any one of claims 220 to 233, wherein each traction projection extends from a first lateral edge of the endless track to a second lateral edge of the endless track.

235. An endless track as defined in claim 229, wherein the height of the traction projection is greatest at a point closer to a center of the endless track in the transversal direction of the endless track than to a first lateral edge of the endless track and than to a second lateral edge of the endless track.

236. An endless track as defined in any one of claims 220 to 235, wherein the vehicle is an all-terrain vehicle (ATV).

237. An endless track as defined in any one of claims 220 to 236, wherein the steering mechanism of the vehicle comprises handlebars.

238. An endless track as defined in any one of claims 220 to 237, wherein the vehicle comprises a seat that is straddled by a driver of the vehicle.

239. A set of endless tracks for a reduced-size vehicle designed primarily for off-highway usage, over undeveloped roads or other unprepared surfaces, each endless track of the set of endless tracks being as defined in any one of claims 220 to 238.

240. A set of endless tracks as defined in claim 239, wherein the set of endless tracks includes four endless tracks.

241. A reduced-size vehicle designed primarily for off-highway usage, over undeveloped roads or other unprepared surfaces, the vehicle comprising an endless track as defined in any one of claims 220 to 238.

242. A reduced-size vehicle designed primarily for off-highway usage, over undeveloped roads or other unprepared surfaces, the vehicle comprising a set of endless tracks as defined in any one of claims 239 and 240.

243. A reduced-size vehicle as defined in any one of claims 241 and 242, wherein the vehicle is an all-terrain vehicle (ATV).

244. A reduced-size vehicle as defined in any one of claims 241 to 243, wherein the steering mechanism of the vehicle comprises handlebars.

245. A reduced-size vehicle as defined in any one of claims 241 to 244, wherein the vehicle includes a seat that is straddled by a driver of the vehicle.

246. A track assembly for a reduced-size vehicle designed primarily for off-highway usage, over undeveloped roads or other unprepared surfaces, the track assembly being steerable by changing an orientation of the track assembly by a steering mechanism of the vehicle, the track assembly comprising:
a) a plurality of wheels including:
i. a drive wheel; and ii. a leading idler wheel and a trailing idler wheel spaced apart from one another in a longitudinal direction of the track assembly;
and b) an endless track mounted around the plurality of wheels, the endless track comprising flexible material to flex around the plurality of wheels, the endless track comprising:
i. an inner surface for facing the plurality of wheels, the drive wheel being rotatable to impart motion to the endless track;
ii. a ground-engaging outer surface opposite to the inner surface;
iii. a plurality of wheel-contacting lugs projecting from the inner surface to contact the plurality of wheels; and iii. a plurality of traction projections projecting from the ground-engaging outer surface and spaced apart in a longitudinal direction of the endless track;
the endless track being free of stiffening inserts extending in a transversal direction of the endless track and disposed within the flexible material at locations of respective ones of the wheel-contacting lugs in the longitudinal direction of the endless track.

247. A track assembly as defined in claim 246, wherein a segment of the endless track extending between the leading idler wheel and the trailing idler wheel defines a ground-engaging run of the endless track, the ground-engaging run including:
- a load bearing section located between the leading idler wheel and the trailing idler wheel and transferring to the ground a major portion of the load carried by the track assembly;
- a leading section extending between the leading idler wheel and the load bearing section and oriented such as to converge toward the ground when the endless track is in motion and propels the vehicle;
and - a trailing section extending between the load bearing section and the trailing idler wheel and oriented such as to diverge from the ground when the endless track is in motion and propels the vehicle.

248. A track assembly as defined in any one of claims 246 and 247, wherein a horizontal distance between an axis of rotation of the leading idler wheel and an axis of rotation of the drive wheel is different from a horizontal distance between an axis of rotation of the trailing idler wheel and the axis of rotation of the drive wheel.

249. A track assembly as defined in claim 248, comprising a support structure including:
- a center portion rotatably supported at the axis of rotation of the drive wheel;
- a first support arm mounted to the center portion and extending along a radial direction of the drive wheel toward a leading end of the track assembly; and - a second support arm mounted to the center portion and extending along a radial direction of the drive wheel toward a trailing end of the track assembly.

250. A track assembly as defined in claim 249, wherein the first support arm defines a first angle with an imaginary horizontal axis which extends through the axis of rotation of the drive wheel, the second support arm defining a second angle with the imaginary horizontal axis, the first angle being different from the second angle.

251. A track assembly as defined in any one of claims 247 to 250, wherein the drive wheel is in rolling contact with the ground-engaging run.

252. A track assembly as defined in any one of claims 248 to 251, wherein the drive wheel is in overlapping relationship with one of the leading idler wheel and the trailing idler wheel, when viewed in a plane that is normal to the axis of rotation of the drive wheel.

253. A track assembly as defined in claim 252, wherein the drive wheel is in overlapping relationship with the trailing idler wheel, when viewed in a plane normal to the axis of rotation of the drive wheel.

254. A track assembly as defined in any one of claims 247 to 253, wherein the load bearing section is located closer to one of the leading idler wheel and the trailing idler wheel than to the other of the leading idler wheel and the trailing idler wheel.

255. A track assembly as defined in claim 249, wherein one of the first and second support arms is longer than the other of the first and second support arms.

256. A track assembly as defined in claim 255, wherein the first support arm and the second support arm define an obtuse angle therebetween.

257. A track assembly as defined in claim 248, wherein the axis of rotation of the drive wheel is located above the axis of rotation of the leading idler wheel and the axis of rotation of the trailing idler wheel.

258. A track assembly as defined in claim 246, wherein the drive wheel has a periphery bound between a first upper horizontal imaginary plane and a first lower horizontal imaginary plane, one of the leading and trailing idler wheels having a periphery bound between a second upper horizontal imaginary plane and a second lower horizontal imaginary plane, the first lower horizontal imaginary plane being positioned below the second upper horizontal imaginary plane.

259. A track assembly as defined in claim 246, wherein the drive wheel has a periphery bound between a first upper horizontal imaginary plane and a first lower horizontal imaginary plane, the leading idler wheel having a periphery bound between a second upper horizontal imaginary plane and a second lower horizontal imaginary plane, the trailing idler wheel having a periphery bound between a third upper horizontal imaginary plane and a third lower horizontal imaginary plane, the first lower horizontal imaginary plane being positioned below the second upper horizontal imaginary plane and below the third upper horizontal imaginary plane.

260. A track assembly as defined in any one of claims 246 to 259, wherein the plurality of wheels imparts a generally triangular path of travel to the endless track.

261. A track assembly as defined in any one of claims 247 to 260, wherein the plurality of wheels define a track supporting and guiding arrangement that is in rolling contact with the inner surface at a plurality of positions, one of said positions being the load bearing section.

262. A track assembly as defined in any one of claims 247 to 261, wherein the load bearing section extends below the leading section.

263. A track assembly as defined in any one of claims 247 to 262, wherein the load bearing section extends below the trailing section.

264. A track assembly as defined in claim 246, wherein an axis of rotation of the drive wheel is located closer to an axis of rotation of a given one of the leading idler wheel and the trailing idler wheel than to an axis of rotation of the other one of the leading idler wheel and the trailing idler wheel in the longitudinal direction of the track assembly.

265. A track assembly as defined in claim 264, wherein the given one of the leading idler wheel and the trailing idler wheel is the trailing idler wheel.

266. A track assembly as defined in any one of claims 246, 264 and 265, comprising a support structure interconnecting the leading idler wheel and the trailing idler wheel.

267. A track assembly as defined in claim 266, wherein the support structure is pivotable about a pivot axis generally parallel to an axis of rotation of the drive wheel.

268. A track assembly as defined in claim 267, wherein the pivot axis of the support structure is coaxial with the axis of rotation of the drive wheel.

269. A track assembly as defined in any one of claims 266 to 268, wherein the support structure comprises a first arm extending towards the leading idler wheel and a second arm extending towards the trailing idler wheel and shorter than the first arm.

270. A track assembly as defined in claim 269, wherein the first arm and the second arm define an obtuse angle therebetween.

271. A track assembly as defined in any one of claims 246 and 264 to 270, wherein a ground-engaging run of the endless track extends between the leading idler wheel and the trailing idler wheel and includes:
- an intermediate section located between the leading idler and the trailing idler;

- a leading section rising from the intermediate section and extending towards the leading idler wheel; and - a trailing section rising from the intermediate section and extending towards the trailing idler wheel.

272. A track assembly as defined in any one of claims 246 to 271, wherein the respective ones of the wheel-contacting lugs register with respective ones of the traction projections in the longitudinal direction of the endless track.

273. A track assembly as defined in any one of claims 246 to 272, wherein the plurality of wheel-contacting lugs includes a plurality of drive lugs for engaging the drive wheel.

274. A track assembly as defined in any one of claims 246 to 273, wherein the plurality of wheel-contacting lugs includes a plurality of guide lugs for contacting the leading idler wheel and the trailing idler wheel.

275. A track assembly as defined in any one of claims 246 to 274, wherein the wheel-contacting lugs are equally spaced in the longitudinal direction of the endless track.

276. A track assembly as defined in any one of claims 246 to 275, wherein the traction projections are equally spaced in the longitudinal direction of the endless track.

277. A track assembly as defined in any one of claims 246 to 276, wherein each traction projection slopes from a central area of the endless track toward lateral end portions of the endless track.

278. A track assembly as defined in any one of claims 246 to 277, wherein each traction projection is generally convex in the transversal direction of the endless track.

279. A track assembly as defined in any one of claims 246 to 278, wherein each traction projection includes a row of traction lugs spaced apart in the transversal direction of the endless track, the endless track including a central area and a pair of lateral end portions on either side of the central area, the row of traction lugs including at least one traction lug adjacent the central area and having a first projection height and at least one traction lug adjacent one of the lateral end portions and having a second projection height, the first projection height exceeding the second projection height.

280. A track assembly as defined in any one of claim 246 to 279, wherein each traction projection has a height that varies in the transversal direction of the endless track.

281. A track assembly as defined in claim 273, wherein the plurality of drive lugs is a first row of drive lugs, the plurality of wheel-contacting lugs including a second row of drive lugs projecting from the inner surface for engaging the drive wheel, the second row of drive lugs being spaced apart from the first row of drive lugs in the transversal direction of the endless track, a drive lug of the first row of drive lugs and a drive lug of the second row of drive lugs being configured to simultaneously engage the drive wheel.

282. A track assembly as defined in any one of claims 246 to 281, wherein a flexibility of the endless track in the transversal direction of the endless track allows the plurality of wheels to bend the endless track in conformance with a profile of the ground.

283. A track assembly as defined in claim 282, wherein the profile of the ground includes a depression and the flexibility of the endless track in the transversal direction of the endless track allows the plurality of wheels to bend the endless track in conformance with the depression.

284. A track assembly as defined in claim 283, wherein the endless track includes a central portion aligned with the drive wheel in the transversal direction of the endless track when the drive wheel imparts motion to the endless track, the flexibility of the endless track in the transversal direction of the endless track allowing the central portion of the endless track to contact the depression.

285. A track assembly as defined in any one of claims 246 to 284, wherein each traction projection extends from a first lateral edge of the endless track to a second lateral edge of the endless track.

286. A track assembly as defined in claim 280, wherein the height of the traction projection is greatest at a point closer to a center of the endless track in the transversal direction of the endless track than to a first lateral edge of the endless track and than to a second lateral edge of the endless track.

287. A track assembly as defined in any one of claims 246 to 286, wherein the vehicle is an all-terrain vehicle (ATV).

288. A track assembly as defined in any one of claims 246 to 287, wherein the steering mechanism of the vehicle comprises handlebars.

289. A track assembly as defined in any one of claims 246 to 288, wherein the vehicle comprises a seat that is straddled by a driver of the vehicle.

290. A set of track assemblies for a reduced-size vehicle designed primarily for off-highway usage, over undeveloped roads or other unprepared surfaces, each track assembly of the set of track assemblies being as defined in any one of claims 246 to 289.

291. A set of track assemblies as defined in claim 290, wherein the set of track assemblies includes four track assemblies.

292. A reduced-size vehicle designed primarily for off-highway usage, over undeveloped roads or other unprepared surfaces, the vehicle comprising a track assembly as defined in any one of claims 246 to 289.

293. A reduced-size vehicle designed primarily for off-highway usage, over undeveloped roads or other unprepared surfaces, the vehicle comprising a set of track assemblies as defined in any one of claims 290 and 291.

294. A reduced-size vehicle as defined in any one of claims 292 and 293, wherein the vehicle is an all-terrain vehicle (ATV).

295. A reduced-size vehicle as defined in any one of claims 292 to 294, wherein the steering mechanism of the vehicle comprises handlebars.

296. A reduced-size vehicle as defined in any one of claims 292 to 295, wherein the vehicle includes a seat that is straddled by a driver of the vehicle.