Traction assembly for a vehicle

This invention relates to a traction assembly for a vehicle. More particularly, the present invention relates to traction assemblies with lower and longitudinally displaced pivoting points.

The type of surfaces over which a vehicle is ridden significantly affects its capacity and efficiency.

While the riding behavior is one of the most important aspects involved in the concept of a vehicle, the ability to allow interchangeability of parts or to retrofit new components on existing vehicles greatly satisfies the owner of vehicles and represents an interesting market source for vendors of specialized parts destined to vehicles such as snowmobiles, motorcycles, all terrain vehicles (ATVs), tractors, trucks, etc.

Specialized parts for those vehicles include kits which may develop the vehicle\'s capacity to accomplish other functions, to extend its duration of use throughout the seasons or to allow the use of the vehicle under different riding conditions.

For instance, different riding kits are sometimes installed to replace the wheels of existing vehicles. In principle, the kits should minimize the need to change existing components, must be able to fit on the vehicle without interference and should try to minimize any negative change to the overall riding behavior of the vehicle and comfort of the driver.

However, since most vehicles are initially designed for a typical use on a specific ground surface, some vehicle parameters like steering, weight distribution or general stability may be affected by different vehicle uses combined with other components such as different riding kits. For example, a better riding behavior on snow usually requires less weight applied to ski assemblies (usually located at the forward portion of the vehicle) than for a regular vehicle riding on another ground surface.

Numerous traction kits have been proposed throughout the years. In “Wheel Mount Track Conversion Assembly” (U.S. Pat. No. 5,607,210 issued on Mar. 4, 1997), Brazier proposes a traction kits to replace the wheels of wheeled vehicles. His system further comprises an anti-torque system that prevents the kit from contacting the vehicle. Though it can be easily mounted on a wheeled vehicle, the system of Brazier does not include particular means to allow a better weight distribution or a better maneuverability of the kit equipped vehicle. Moreover, the traction kit of Brazier can only pivot around the axle axis.

In “Conversion System for All Terrain Vehicles” (U.S. Pat. No. 6,095,275 issued on Aug. 1, 2000), Shaw proposes an ATV equipped with conversion kits such as ski assemblies and traction assemblies to replace existing wheels. Although adapting to the existing power system, the conversion system does not provide adjustability means for the weight distribution of the vehicle, such that the ATV\'s weight is dispersed to the ground surface through the traction and ski assemblies. Also, as for Brazier, the traction kit of Shaw can only pivot around the axis of the axle.

The problem with these particular arrangements is that in order to follow the bumps and depressions of the terrain over which the vehicle is ridden, the traction kit needs to pivot around the axis of the axle, which implies unnecessary large movements of the traction kit. These large movements are translated into an uncomfortable ride for the user. Furthermore, these traction kits generally need means to prevent any contact between the traction assembly and the body of the vehicle. These means generally add to the weight and cost of the assembly.

There is therefore a need for a traction assembly which improves riding condition when traction assemblies are used to replace existing wheels on vehicles.

Accordingly, an object of the present invention is to provide a traction assembly for a vehicle which uses an endless traction band.

Another object of the present invention is to provide a traction assembly which is compact and easily retrofitted on a vehicle.

Another object of the present invention is to provide a traction assembly which can be easily installed either in the front or in the back of a vehicle or both.

Other and further objects and advantages of the present invention will be obvious upon an understanding of the illustrative embodiments about to be described or will be indicated in the appended claims, and various advantages not referred to herein will occur to one skilled in the art upon employment of the invention in practice.

To attain these and other objects which will become more apparent as the description proceeds according to one aspect of the present invention, there is provided a traction assembly.

The object of the present invention involves a traction assembly that can preferably replace a wheel on vehicle. The traction assembly thus involves a vehicle with a frame and at least one traction axle. Preferably, the traction assembly can replace wheels on either side of the front portion and/or the rear portion of the vehicle.

More particularly, the traction assembly includes a sprocket wheel and a longitudinally extending traction band cooperating with such sprocket wheel. The sprocket wheel is preferably fixedly attached by means known in the art to the traction axle (or the wheel hub) of the vehicle. The traction assembly also comprises a support structure, sometimes in the form of a slider bar, on which at least one but preferably two idler wheels are pivotally mounted. These idlers wheels are preferably mounted at the extremities of the support structure. A plurality of road wheels can also be pivotally mounted on either side the support structure to increase the stability of the traction band.

In a first embodiment, the support structure (or slider bar) is connected to the vehicle via a member which is non-drivingly mounted on the sprocket wheel (or an extension thereof). More precisely, the first end of the member is non-drivingly attached to the sprocket wheel or to a laterally extending structure axially extending from the sprocket wheel. This first end is preferably attached to the sprocket wheel or to the laterally extending support with rollers or ball-bearings. The second end is attached to a pivot point located under the traction axle, on the support structure (or slider bar) and preferably longitudinally displaced in relation to such traction axle. The member is preferably rigid and can be adjustable.

To increase the adjustability of the pivot point, protuberances extending toward or in vicinity of the sprocket wheel can be provided on the support structure These protuberances include at least one and preferably a plurality of pivot points to which the member can be pivotally attached.