CA2822562C

CA2822562C - Track assembly for an all-terrain vehicle

Info

Publication number: CA2822562C
Application number: CA2822562A
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: 2015-05-26
Anticipated expiration: 2022-05-30
Also published as: CA2822562A1; CA2825509C; CA2388294A1; CA2388294C; CA2388294F; CA2825509A1

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.

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 a steerable 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: an outer ground-engaging surface; an inner surface opposite to the outer ground-engaging surface; a plurality of drive projections projecting from the inner surface and arranged longitudinally along the track; and a plurality of traction projections projecting from the outer ground-engaging surface and arranged longitudinally along the track.
The endless track is free of stiffening members extending transversally of the endless track at longitudinally spaced locations at which a drive projection registers with a traction projection.
[0006B] In accordance with another aspect of the present invention, there is provided a steerable 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 an endless track and a plurality of wheels for supporting and driving the endless track. The endless track includes: an outer ground-engaging surface; an inner surface opposite to the outer ground-engaging surface; a plurality of drive projections projecting from the inner surface and arranged longitudinally along the track; and a plurality of traction projections projecting from the outer ground-engaging surface and arranged longitudinally along the track. The endless track is free of stiffening members extending transversally of the endless track at longitudinally spaced locations at which a drive projection registers with a traction projection.
[0006C] In accordance with another aspect of the present invention, there is provided a steerable 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 a plurality of drive lugs projecting from an inner surface of the endless track and a plurality of traction projections projecting from an outer ground-engaging surface of the endless track.
The endless track is free of stiffening members extending transversally of the endless track at areas of the endless track where a drive lug registers in a longitudinal direction of the endless track with a traction projection.
[0006D] In accordance with another aspect of the present invention, there is provided a steerable 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 steerable track assembly by a steering mechanism of the vehicle. The steerable track assembly comprises an endless track and a plurality of wheels for supporting and driving the endless track. The endless track comprises a plurality of drive lugs projecting from an inner surface of the endless track and a plurality of traction projections projecting from an outer ground-engaging surface of the endless track. The endless track is free of stiffening members extending transversally of the endless track at areas of the endless track where a drive lug registers in a longitudinal direction of the endless track with a traction projection.

[0006E] In accordance with another aspect of the present invention, there is provided a method for reducing a transverse rigidity of a steerable endless track for use in 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 a plurality of track segments following in succession in a longitudinal direction of the endless track, each track segment including a drive projection projecting from an inner surface of the endless track and a traction projection projecting from an outer ground-engaging surface of the endless track.
The drive projection registers in the longitudinal direction of the endless track with the traction projection. The method comprises manufacturing the endless track without providing a stiffening member extending transversally of the endless track in a portion of each track segment between the drive projection and the traction projection.
[0006F] In accordance with yet 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. The track assembly 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. The endless track comprises flexible material to flex around the plurality of wheels. The plurality of wheels includes a drive wheel for imparting motion to the endless track. The endless track comprising: an inner surface for facing the plurality of wheels; a ground-engaging outer surface opposite to the inner surface; a plurality of drive projections projecting from the inner surface, distributed in a longitudinal direction of the endless track, and positioned to engage the drive wheel; and a plurality of traction projections projecting from the ground-engaging outer surface and distributed in the longitudinal direction of the endless track. The endless track is free of stiffening inserts extending transversally to the longitudinal direction of the endless track and disposed within the flexible material at areas of the endless track where a given one of the drive projections registers in the longitudinal direction of the endless track with a given one of the traction projections.
[0006G] In accordance with yet 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. The track assembly is steerable by changing an orientation of the track assembly by a steering mechanism of the ATV. The track assembly comprising: a plurality of wheels;
and an endless track disposed around the plurality of wheels. 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; a ground-engaging outer surface opposite to the inner surface; a plurality of drive projections projecting from the inner surface and distributed in a longitudinal direction of the endless track; and a plurality of traction projections projecting from the ground-engaging outer surface and distributed in the longitudinal direction of the endless track. The endless track is free of stiffening inserts extending transversally to the longitudinal direction of the endless track and disposed within the flexible material at areas of the endless track where a given one of the drive projections registers in the longitudinal direction of the endless track with a given one of the traction projections.
[0006H] In accordance with yet another aspect of the present invention, there is provided a method for reducing a transverse rigidity of an endless track for use in an all-terrain vehicle (ATV). The endless track is steerable by changing an orientation of the endless track by a steering mechanism of the ATV. The endless track comprises flexible material to flex around a plurality of wheels. The endless track comprises a plurality of track segments following in succession in a longitudinal direction of the endless track, each track segment including a drive projection projecting from an inner surface of the endless track and a traction projection projecting from a ground-engaging outer surface of the endless track. The drive projection registers in the longitudinal direction of the endless track with the traction projection. The method comprises manufacturing the endless track without disposing a stiffening insert extending transversally to the longitudinal direction of the endless track within the flexible material in a portion of each track segment between the drive projection and the traction projection.
[00061] 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. The track assembly 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. 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 rods 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.
[0006J] 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. The track assembly 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 including: a drive wheel; and 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 track assembly further comprises an endless track mounted around the plurality of wheels. The endless track comprises: an inner surface for facing the plurality of wheels, the drive wheel being rotatable to impart motion to the endless track;
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 rods 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.
[0006K] 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. The track assembly 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. 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; 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 rods 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.
[0006L] 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. The track assembly 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; and 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, the drive wheel being rotatable to impart motion to the endless track; 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 rods 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.

[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 riving 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 non-restrictive 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;
100171 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 elevational 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 11 is 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 7010 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 suifaces 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.
[00581 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 belt 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.
100641 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 29 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 of 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. For example, one could provide a guiding rail having a convex profile and transversally convex lugs to achieve similar results.
[0068] 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, and remain within the scope of the invention as defined in the appended claims.

Claims

'17 CLAIMS:

1. A steerable 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:
(a) an outer ground-engaging surface:
(b) an inner surface opposite to the outer ground-engaging surface;
(c) a plurality of drive projections projecting from the inner surface and arranged longitudinally along the track; and (d) a plurality of traction projections projecting from the outer ground-engaging surface and arranged longitudinally along the track;
the endless track being free of stiffening members extending transversally of the endless track at longitudinally spaced locations at which a drive projection registers with a traction projection.

2. A steerable endless track as defined in claim 1, wherein the drive projections are equally spaced in a longitudinal direction of the endless track.

3. A steerable endless track as defined in any one of claims 1 and 2, wherein the traction projections are equally spaced in a longitudinal direction of the endless track.

4. A steerable endless track as defined in any one of claims 1 to 3, wherein each traction projection slopes from a central area of the endless track toward lateral end portions of the track.

5. A steerable endless track as defined in any one of claims 1 to 4, wherein each traction projection is generally convex in a transverse direction of the endless track.

6. A steerable endless track as defined in any one of claims 1 to 3, wherein each traction projection includes a row of traction lugs spaced apart in a transverse 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 proximal the central area and having a first projection height and at least one traction lug proximal one of the lateral end portions and having a second projection height, the first projection height exceeding the second projection height.

7. A steerable endless track as defined in any one of claim 1 to 4, wherein each traction projection varies in height in a transverse direction of the endless track.

8. A steerable endless track as defined in any one of claims 1 to 7, wherein the plurality of drive projections is a first row of drive projections, the endless track comprising a second row of drive projections projecting from the inner surface and arranged longitudinally along the endless track, the first row of drive projections and the second row of drive projections being spaced apart in a transverse direction of the endless track, a drive projection of the first row of drive projections and a drive projection of the second row of drive projections being configured to simultaneously engage a drive wheel which imparts motion to the endless track.

9. A steerable endless track as defined in any one of claims 1 to 8, wherein the vehicle is an All-Terrain Vehicle (ATV).

10. A steerable endless track as defined in any one of claims 1 to 9, wherein the steering mechanism of the vehicle has handlebars.

11. A steerable endless track as defined in any one of claims 1 to 10, wherein the vehicle includes a seat that is straddled by a driver of the vehicle.

12. A pair of endless tracks for a reduced-size vehicle designed primarily for off-highway usage, over undeveloped roads or other unprepared surfaces, wherein each endless track of the pair of endless tracks is a steerable endless track as defined in any one of claims 1 to 11.

13. A steerable 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) an endless track including:
i. an outer ground-engaging surface;
ii. an inner surface opposite to the outer ground-engaging surface;
iii. a plurality of drive projections projecting from the inner surface and arranged longitudinally along the track;
iv. a plurality of traction projections projecting from the outer ground-engaging surface and arranged longitudinally along the track;
the endless track being free of stiffening members extending transversally of the endless track at longitudinally spaced locations at which a drive projection registers with a traction projection; and (b) a plurality of wheels for supporting and driving the endless track.

14. A steerable track assembly as defined in claim 13, wherein the plurality of wheels includes:
(a) a leading idler and a trailing idler, the leading and trailing idlers being in a spaced apart relationship, a segment of the endless track extending between the leading and trailing idlers defining a ground engaging run;
(b) a drive wheel in driving engagement with the endless track for imparting movement to the endless track.

15. A steerable track assembly as defined in claim 14, wherein the ground engaging run includes:
(a) a load bearing section located between the leading idler and the trailing idler, the load bearing section transferring to the ground surface a major portion of the load carried by the track assembly;
(b) a leading section extending between the leading idler and the load bearing section, the leading section being oriented such as to converge toward the ground surface when the endless track is in motion and propels the vehicle;
and (c) a trailing section extending between the load bearing section and the trailing idler, the trailing section being oriented such as to diverge from the ground surface when the endless track is in motion and propels the vehicle.

16. A steerable track assembly as defined in any one of claims 14 to 15, wherein the leading idler rotates about a first axis of rotation, the trailing idler rotates about a second axis of rotation and the drive wheel rotates about a third axis of rotation, a first horizontal distance defined between the first axis of rotation and the third axis of rotation being different from a second horizontal distance defined between the second axis of rotation and the third axis of rotation.

17. A steerable track assembly as defined in claim 16, including a support structure having:
i) a center portion rotatably supported at the third axis of rotation;
ii) 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;
iii) 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.

18. A steerable track assembly as defined in claim 17, wherein the first support arm defines a first angle with an imaginary horizontal axis which extends through the third axis of rotation, the second support arm defines a second angle with the imaginary horizontal axis, and the first angle is different from the second angle.

19. A steerable track assembly as defined in any one of claims 14 to 18, wherein the drive wheel is in rolling contact with the ground engaging run.

20. A steerable track assembly as defined in any one of claims 16 to 19, wherein the drive wheel is in overlapping relationship with one of the leading and trailing idlers, when viewed in a plane that is normal to the third axis of rotation.

21. A steerable track assembly as defined in claim 20, wherein the drive wheel is in overlapping relationship with the trailing idler, when viewed in a plane normal to the third axis of rotation.

22. A steerable track assembly as defined in any one of claims 15 to 21, wherein the load bearing section is located closer to one of the leading and trailing idlers than to the other of the leading and trailing idlers.

23. A steerable track assembly as defined in claim 17, wherein one of the first and second support arms is longer than the other of the first and second support arms.

24. A steerable track assembly as defined in claim 17, wherein the first support arm and the second support arm define an obtuse angle therebetween.

25. A steerable track assembly as defined in claim 16, wherein the third axis of rotation is located above the first axis of rotation and the second axis of rotation.

26. A steerable track assembly as defined in claim 16, 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 idlers 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.

27. A steerable track assembly as defined in claim 16, 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 having a periphery bound between a second upper horizontal imaginary plane and a second lower horizontal imaginary plane, the trailing idler 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.

28. A steerable track assembly as defined in any one of claims 13 to 27, wherein the plurality of wheels imparts a generally triangular path of travel to the endless track.

29. A steerable track assembly as defined in any one of claims 15 to 27, 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.

30. A steerable track assembly as defined in any one of claims 15 to 29, wherein the load bearing section extends below the leading section.

31. A steerable track assembly as defined in any one of claims 15 to 30, wherein the load bearing section extends below the trailing section.

32. A steerable track assembly as defined in any one of claims 13 to 31, wherein the drive projections are equally spaced in a longitudinal direction of the endless track.

33. A steerable track assembly as defined in any one of claims 13 to 32, wherein the traction projections are equally spaced in a longitudinal direction of the endless track.

34. A steerable track assembly as defined in any one of claims 13 to 33, wherein each traction projection slopes from a central area of the endless track toward lateral end portions of the endless track.

35. A steerable track assembly as defined in any one of claims 13 to 34, wherein each traction projection is generally convex in a transverse direction of the endless track.

36. A steerable track assembly as defined in any one of claims 13 to 35, wherein each traction projection includes a row of traction lugs spaced apart in a transverse 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 in the central area and having a first projection height and at least one traction lug proximal one of the lateral end portions and having a second projection height, the first projection height exceeding the second projection height.

37. A steerable track assembly as defined in any one of claim 13 to 34, wherein each traction projection varies in height in a transverse direction of the endless track.

38. A steerable track assembly as defined in any one of claims 14 to 37, wherein the plurality of drive projections is a first row of drive projections, the endless track comprising a second row of drive projections projecting from the inner surface and arranged longitudinally along the endless track, the first row of drive projections and the second row of drive projections being spaced apart in a transverse direction of the endless track, a drive projection of the first row of drive projections and a drive projection of the second row of drive projections being configured to simultaneously engage the drive wheel.

39. A steerable track assembly as defined in any one of claims 13 to 38, wherein the vehicle is an All-Terrain Vehicle (ATV).

40. A steerable track assembly as defined in any one of claims 13 to 39, wherein the steering mechanism of the vehicle has handlebars.

41. A steerable track assembly as defined in any one of claims 13 to 40, wherein the vehicle includes a seat that is straddled by a driver of the vehicle.

42. A pair of steerable track assemblies for a reduced-size vehicle designed primarily for off-highway usage, over undeveloped roads or other unprepared surfaces, wherein each of the steerable track assemblies is as defined in any one of claims 13 to 41.

43. A steerable 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 a plurality of drive lugs projecting from an inner surface of the endless track and a plurality of traction projections projecting from an outer ground-engaging surface of the endless track, the endless track being free of stiffening members extending transversally of the endless track at areas of the endless track where a drive lug registers in a longitudinal direction of the endless track with a traction projection.

44. A steerable endless track as defined in claim 43, wherein the traction projection slopes from a central area of the endless track toward lateral end portions of the endless track.

45. A steerable endless track as defined in any one of claims 43 and 44, wherein the traction projection is generally convex in a transverse direction of the endless track.

46. A steerable endless track as defined in any one of claims 43 to 45, wherein the traction projection includes a row of traction lugs spaced apart in a transverse 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 in the central area and having a first projection height and at least one traction lug proximal one of the lateral end portions and having a second projection height, the first projection height exceeding the second projection height.

47. A steerable endless track as defined in any one of claim 43 to 44, wherein each traction projection varies in height in a transverse direction of the endless track.

48. A steerable endless track as defined in any one of claims 43 to 47, wherein the drive lug registering in the longitudinal direction of the endless track with a traction projection is a first drive lug and the endless track includes a second drive lug spaced from the first drive lug in a transverse direction of the endless track, the first and second drive lugs being configured to simultaneously engage a drive wheel as the drive wheel imparts motion to the endless track.

49. A steerable endless track as defined in any one of claims 43 to 48, wherein the vehicle is an All-Terrain Vehicle (ATV).

50. A steerable endless track as defined in any one of claims 43 to 49, wherein the steering mechanism of the vehicle has handlebars.

51. A steerable endless track as defined in any one of claims 43 to 50, wherein the vehicle includes a seat that is straddled by a driver of the vehicle.

52. A set of four endless tracks for a reduced-size vehicle designed primarily for off-highway usage, over undeveloped roads or other unprepared surfaces, wherein at least two of the endless tracks in the set of four is a steerable endless track as defined in any one of claims 43 to 51.

53. A steerable 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 steerable track assembly by a steering mechanism of the vehicle, the steerable track assembly comprising:
a) an endless track comprising a plurality of drive lugs projecting from an inner surface of the endless track and a plurality of traction projections projecting from an outer ground-engaging surface of the endless track, the endless track being free of stiffening members extending transversally of the endless track at areas of the endless track where a drive lug registers in a longitudinal direction of the endless track with a traction projection; and b) a plurality of wheels for supporting and driving the endless track.

54. A steerable track assembly as defined in claim 53, wherein the plurality of wheels includes:
a. a leading idler and a trailing idler in a spaced apart relationship, a segment of the endless track extending between the leading and trailing idlers defining a ground engaging run; and b.a drive wheel in driving engagement with the endless track for imparting movement to the endless track.

55. A steerable track assembly as defined in claim 54, wherein the ground engaging run includes:
a. a load bearing section located between the leading idler and the trailing idler, the load bearing section transferring to the ground surface a major portion of the load carried by the track assembly;
b. a leading section extending between the leading idler and the load bearing section, the leading section being oriented such as to converge toward the ground surface when the endless track is in motion and propels the vehicle in a forward direction;
c. a trailing section extending between the load bearing section and the trailing idler, the trailing section being oriented such as to diverge from the ground surface when the endless track is in motion and propels the vehicle in the forward direction.

56. A steerable track assembly as defined in claim 55, wherein the leading idler rotates about a first axis of rotation, the trailing idler rotates about a second axis of rotation and the drive wheel rotates about a third axis of rotation, a first horizontal distance defined between the first axis of rotation and the third axis of rotation being different from a second horizontal distance defined between the second axis of rotation and the third axis of rotation.

57. A steerable track assembly as defined in claim 56, including a support structure having:
i) a center portion rotatably supported at the third axis of rotation;
ii) 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;
iii) 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.

58. A steerable track assembly as defined in claim 57, wherein the first support arm defines a first angle with an imaginary horizontal axis which extends through the third axis of rotation, the second support arm defines a second angle with the imaginary horizontal axis, and the first angle is different from the second angle.

59. A steerable track assembly as defined in any one of claims 54 to 58, wherein the drive wheel is in rolling contact with the ground engaging run.

60. A steerable track assembly as defined in any one of claims 54 to 59, wherein the drive wheel is in overlapping relationship with one of the leading and trailing idlers, when viewed in a plane that is normal to the third axis of rotation.

61. A steerable track assembly as defined in claim 60, wherein the drive wheel is in overlapping relationship with the trailing idler, when viewed in a plane normal to the third axis of rotation.

62. A steerable track assembly as defined in any one of claims 54 to 61, wherein the load bearing section is located closer to one of the leading and trailing idlers than to the other of the leading and trailing idlers.

63. A steerable track assembly as defined in claim 57, wherein one of the first and second support arms is longer than the other of the first and second support arms.

64. A steerable track assembly as defined in claim 57, wherein the first support arm and the second support arm define an obtuse angle therebetween.

65. A steerable track assembly as defined in claim 56, wherein the third axis is located above the first axis and the second axis.

66. A steerable track assembly as defined in claim 54, 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 idlers 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.

67. A steerable track assembly as defined in claim 54, 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 having a periphery bound between a second upper horizontal imaginary plane and a second lower horizontal imaginary plane, the trailing idler 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.

68. A steerable track assembly as defined in any one of claims 53 to 67, wherein the plurality of wheels impart a generally triangular path of travel to the endless track.

69. A steerable track assembly as defined in any one of claims 53 to 68, 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 locations, one of said locations being the load bearing section.

70. A steerable rack assembly as defined in any one of claims 55 to 69, wherein the load bearing section extends below the leading section.

71. A steerable track assembly as defined in any one of claims 55 to 70, wherein the load bearing section extends below the trailing section.

72. A steerable track assembly as defined in any one of claims 53 to 71, wherein the traction projection slopes from a central area of the endless track toward lateral end portions of the endless track.

73. A steerable track assembly as defined in any one of claims 53 to 72, wherein the traction projection is generally convex in a transverse direction of the endless track.

74. A steerable track assembly as defined in any one of claims 53 to 73, wherein the traction projection includes a row of traction lugs spaced apart in a transverse 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 in 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.

75. A steerable track assembly as defined in any one of claims 53 to 71, wherein each traction projection varies in height in a transverse direction of the endless track.

76. A steerable track assembly as defined in any one of claims 54 to 75, wherein the drive lug registering in the longitudinal direction of the endless track with a traction projection is a first drive lug and the endless track includes a second drive lug spaced from the first drive lug in a transverse direction of the endless track, the first and second drive lugs being configured to simultaneously engage the drive wheel as the drive wheel imparts motion to the endless track.

77. A steerable track assembly as defined in any one of claims 53 to 76, wherein the vehicle is an All-Terrain Vehicle (ATV).

78. A steerable track assembly as defined in any one of claims 53 to 77, wherein the steering mechanism of the vehicle has handlebars.

79. A steerable track assembly as defined in any one of claims 53 to 78, wherein the vehicle includes a seat that is straddled by a driver of the vehicle.

80. A set of steerable track assemblies for a reduced-size vehicle designed primarily for off-highway usage, over undeveloped roads or other unprepared surfaces, wherein each of at least two of the steerable track assemblies is as defined in any one of claims 53 to 79.

81. A reduced-size vehicle designed primarily for off-highway usage, over undeveloped roads or other unprepared surfaces, the reduced-size vehicle including the steerable endless track as defined in any one of claims 1 to 8.

82. A reduced-size vehicle as defined in claim 81, wherein the vehicle is an All-Terrain Vehicle (ATV).

83. A reduced-size vehicle as defined in any one of claims 81 and 82, wherein the steering mechanism of the vehicle has handlebars.

84. A reduced-size vehicle as defined in any one of claims 81 to 83, wherein the vehicle includes a seat that is straddled by a driver of the vehicle.

85. A reduced-size vehicle as defined in any one of claims 81 to 84, wherein the vehicle includes a plurality of transverse pairs of track assemblies, each track assembly including an endless track, a leading pair of the plurality of track assemblies being steerable and including each the steerable endless track.

86. A reduced-size vehicle designed primarily for off-highway usage, over undeveloped roads or other unprepared surfaces, the reduced-size vehicle including the steerable track assembly as defined in any one of claims 13 to 38.

87. A reduced-size vehicle as defined in claim 86, wherein the vehicle is an All-Terrain Vehicle (ATV).

88. A reduced-size vehicle as defined in any one of claims 86 and 87, wherein the steering mechanism of the vehicle has handlebars.

89. A reduced-size vehicle as defined in any one of claims 86 to 88, wherein the vehicle includes a seat that is straddled by a driver of the vehicle.

90. A reduced-size vehicle as defined in any one of claims 86 to 89, wherein the vehicle includes a plurality of transverse pairs of track assemblies, each track assembly including an endless track, a transverse pair of the steerable track assemblies being mounted at a leading end of the vehicle.

91. A reduced-size vehicle designed primarily for off-highway usage, over undeveloped roads or other unprepared surfaces, the reduced-size vehicle including the steerable track as defined in any one of claims 43 to 48.

92. A reduced-size vehicle as defined in claim 91, wherein the vehicle is an All-Terrain Vehicle (ATV).

93. A reduced-size vehicle as defined in any one of claims 91 and 92, wherein the steering mechanism of the vehicle has handlebars.

94. A reduced-size vehicle as defined in any one of claims 91 to 93, wherein the vehicle includes a seat that is straddled by a driver of the vehicle.

95. A reduced-size vehicle as defined in any one of claims 91 to 94, wherein the vehicle includes a plurality of transverse pairs of track assemblies, each track assembly including an endless track, a transverse pair of the steerable track assemblies being mounted at a leading end of the vehicle.

96. A reduced-size vehicle designed primarily for off-highway usage, over undeveloped roads or other unprepared surfaces, the reduced-size vehicle including the steerable track assembly as defined in any one of claims 53 to 76.

97. A reduced-size vehicle as defined in claim 96, wherein the vehicle is an All-Terrain Vehicle (ATV).

98. A reduced-size vehicle as defined in any one of claims 96 and 97, wherein the steering mechanism of the vehicle has handlebars.

99. A reduced-size vehicle as defined in any one of claims 96 to 98, wherein the vehicle includes a seat that is straddled by a driver of the vehicle.

100. A reduced-size vehicle as defined in any one of claims 96 to 99, wherein the vehicle includes a plurality of transverse pairs of track assemblies, each track assembly including an endless track, a transverse pair of the steerable track assemblies being mounted at a leading end of the vehicle.

101. A method for reducing a transverse rigidity of a steerable endless track for use in 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 a plurality of track segments following in succession in a longitudinal direction of the endless track, each track segment including a drive projection projecting from an inner surface of the endless track and a traction projection projecting from an outer ground-engaging surface of the endless track, the drive projection registering in the longitudinal direction of the endless track with the traction projection, the method comprising manufacturing the endless track without providing a stiffening member extending transversally of the endless track in a portion of each track segment between the drive projection and the traction projection.

102. 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 comprising flexible material to flex 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 drive projections projecting from the inner surface, distributed in a longitudinal direction of the endless track, and positioned to engage the drive wheel; and c) a plurality of traction projections projecting from the ground-engaging outer surface and distributed in the longitudinal direction of the endless track;
the endless track being free of stiffening inserts extending transversally to the longitudinal direction of the endless track and disposed within the flexible material at areas of the endless track where a given one of the drive projections registers in the longitudinal direction of the endless track with a given one of the traction projections.

103. An endless track as defined in claim 102, wherein the given one of the traction projections slopes from a central area of the endless track toward lateral end portions of the endless track.

104. An endless track as defined in any one of claims 102 and 103, wherein the given one of the traction projections is generally convex in a transverse direction of the endless track.

105. An endless track as defined in any one of claims 102 to 104, wherein the given one of the traction projections includes a row of traction lugs spaced apart in a transverse 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 in the central area and having a first projection height and at least one traction lug proximal one of the lateral end portions and having a second projection height, the first projection height exceeding the second projection height.

106. An endless track as defined in any one of claim 102 to 105, wherein the given one of the traction projections varies in height in a transverse direction of the endless track.

107. An endless track as defined in any one of claims 102 to 106, wherein the given one of the drive projections registering in the longitudinal direction of the endless track with the given one of the traction projections is a first given one of the drive projections, a second given one of the drive projections being spaced from the first given one of the drive projections in a transverse direction of the endless track, the first given one of the drive projections and the second given one of the drive projections being configured to simultaneously engage the drive wheel.

108. An endless track as defined in any one of claims 102 to 107, wherein the steering mechanism of the ATV comprises handlebars.

109. An endless track as defined in any one of claims 102 to 108, wherein the ATV
comprises a straddle seat for a driver of the ATV.

110. A set of four endless tracks for providing traction to an all-terrain vehicle (ATV), wherein each of at least two of the endless tracks in the set of four endless tracks is an endless track as defined in any one of claims 102 to 110.

111. 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; and b) an endless track disposed around the plurality of wheels, the endless track comprising flexible material to flex around the plurality of wheels, the endless track comprising:
- an inner surface for facing the plurality of wheels;
- a ground-engaging outer surface opposite to the inner surface;
- a plurality of drive projections projecting from the inner surface and distributed in a longitudinal direction of the endless track;
and - a plurality of traction projections projecting from the ground-engaging outer surface and distributed in the longitudinal direction of the endless track;
the endless track being free of stiffening inserts extending transversally to the longitudinal direction of the endless track and disposed within the flexible material at areas of the endless track where a given one of the drive projections registers in the longitudinal direction of the endless track with a given one of the traction projections.

112. A track assembly as defined in claim 111, wherein the plurality of wheels includes:
- a leading idler wheel and a trailing idler wheel spaced apart in a longitudinal direction of the track assembly, a segment of the endless track extending between the leading idler wheel and the trailing idler wheel defining a ground-engaging run of the endless track; and - a drive wheel for imparting movement to the endless track.

113. A track assembly as defined in claim 112, wherein the ground-engaging run of the endless track comprises:
- a load bearing section located between the leading idler wheel and the trailing idler wheel and transferring to the ground surface 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, the leading section being oriented such as to converge toward the ground surface when the endless track is in motion and propels the ATV in a forward direction; and - a trailing section extending between the load bearing section and the trailing idler wheel, the trailing section being oriented such as to diverge from the ground surface when the endless track is in motion and propels the ATV in the forward direction.

114. A track assembly as defined in any one of claims 112 and 113, wherein the leading idler wheel rotates about a first axis of rotation, the trailing idler wheel rotates about a second axis of rotation and the drive wheel rotates about a third axis of rotation, a first horizontal distance defined between the first axis of rotation and the third axis of rotation being different from a second horizontal distance defined between the second axis of rotation and the third axis of rotation.

115. A track assembly as defined in claim 114, comprising a support structure having:
- a center portion rotatably supported at the third axis of rotation;
- 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.

116. A track assembly as defined in claim 115, wherein the first support arm defines a first angle with an imaginary horizontal axis which extends through the third axis of rotation, the second support arm defines a second angle with the imaginary horizontal axis, and the first angle is different from the second angle.

117. A track assembly as defined in any one of claims 112 to 116, wherein the drive wheel is in rolling contact with the ground-engaging run of the endless track.

118. A track assembly as defined in any one of claims 114 to 117, 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 third axis of rotation.

119. A track assembly as defined in claim 118, wherein the drive wheel is in overlapping relationship with the trailing idler wheel, when viewed in a plane normal to the third axis of rotation.

120. A track assembly as defined in any one of claims 113 to 119, 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.

121. A track assembly as defined in claim 115, wherein one of the first and second support arms is longer than the other of the first and second support arms.

122. A track assembly as defined in claim 121, wherein the first support arm and the second support arm define an obtuse angle therebetween.

123. A track assembly as defined in claim 114, wherein the third axis of rotation is located above the first axis of rotation and the second axis of rotation.

124. A track assembly as defined in claim 112, 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 idler wheel and the trailing idler wheel 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.

125. A track assembly as defined in claim 112, 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.

126. A track assembly as defined in any one of claims 111 to 125, wherein the plurality of wheels impart a generally triangular path of travel to the endless track.

127. A track assembly as defined in any one of claims 113 to 126, 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 locations, one of said locations being the load bearing section.

128. A track assembly as defined in any one of claims 113 to 127, wherein the load bearing section extends below the leading section.

129. A track assembly as defined in any one of claims 113 to 128, wherein the load bearing section extends below the trailing section.

130. A track assembly as defined in any one of claims 111 to 129, wherein the given one of the traction projections slopes from a central area of the endless track toward lateral end portions of the endless track.

131. A track assembly as defined in any one of claims 111 to 120, wherein the given one of the traction projections is generally convex in a transverse direction of the endless track.

132. A track assembly as defined in any one of claims 111 to 131, wherein the given one of the traction projections includes a row of traction lugs spaced apart in a transverse 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 in the central area and having a first projection height and at least one traction lug proximal one of the lateral end portions and having a second projection height, the first projection height exceeding the second projection height.

133. A track assembly as defined in any one of claims 111 to 132, wherein the given one of the traction projections varies in height in a transverse direction of the endless track.

134. A track assembly as defined in any one of claims 111 to 133, wherein the given one of the drive projections registering in the longitudinal direction of the endless track with the given one of the traction projections is a first given one of the drive projections, a second given one of the drive projections being spaced from the first given one of the drive projections in a transverse direction of the endless track, the first given one of the drive projections and the second given one of the drive projections being configured to simultaneously engage the drive wheel.

135. A track assembly as defined in any one of claims 111 to 134, wherein the steering mechanism of the ATV comprises handlebars.

136. A track assembly as defined in any one of claims 111 to 135, wherein the ATV
comprises a straddle seat for a driver of the ATV.

137. A set of track assemblies for traction of an all-terrain vehicle (ATV), wherein each of at least two of the track assemblies is a track assembly as defined in any one of claims 111 to 136.

138. An ATV comprising the endless track as defined in any one of claims 102 to 107.

139. An ATV as defined in claim 138, wherein the steering mechanism of the ATV

comprises handlebars.

140. An ATV as defined in any one of claims 138 and 139, wherein the ATV
comprises a straddle seat for a driver of the ATV.

141. An ATV as defined in any one of claims 138 to 140, wherein the ATV
includes a plurality of transverse pairs of track assemblies, each track assembly including an endless track, a leading pair of the plurality of track assemblies being steerable and including each the endless track.

142. An ATV comprising the track assembly as defined in any one of claims 111 to 134.

143. An ATV as defined in claim 142, wherein the steering mechanism of the ATV

comprises handlebars.

144. An ATV as defined in any one of claims 142 and 143, wherein the ATV
comprises a straddle seat for a driver of the ATV.

145. An ATV as defined in any one of claims 142 to 144, wherein the ATV
includes a plurality of transverse pairs of track assemblies, each track assembly including an endless track, a leading pair of the plurality of track assemblies being steerable and including each the endless track.

146. A method for reducing a transverse rigidity of an endless track for use in an all-terrain vehicle (ATV), the endless track being steerable by changing an orientation of the endless track by a steering mechanism of the ATV, the endless track comprising flexible material to flex around a plurality of wheels, the endless track comprising a plurality of track segments following in succession in a longitudinal direction of the endless track, each track segment including a drive projection projecting from an inner surface of the endless track and a traction projection projecting from a ground-engaging outer surface of the endless track, the drive projection registering in the longitudinal direction of the endless track with the traction projection, the method comprising manufacturing the endless track without disposing a stiffening insert extending transversally to the longitudinal direction of the endless track within the flexible material in a portion of each track segment between the drive projection and the traction projection.