Drive track for snowmobile or tracked vehicle

A track formed of a molded rubber base sandwiching a cord layer, followed by a cross bar and a single layer of ply fabric extending longitudinally of the track.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims priority on Canadian application no. 2,509,059, filed on Jun. 2, 2005. All documents above are herein incorporated by reference.

FIELD OF THE INVENTION

The present invention pertains to a drive track and, more particularly, to a track for snowmobiles or other tracked vehicles, having an improved construction to decrease horse power, increase top speed and improve durability of the track when the latter is driven at high rotational speeds.

BACKGROUND OF THE INVENTION

Endless drive tracks for propelling, for example, a snowmobile over snow, ice or other similar ground structure, are known in the art. The mounting of this track to a snowmobile and the mounting of such track on an all-terrain vehicle are well known. The track has a ground engaging outer side and an inner side that receives and supports, on the lower run thereof, a suspension which may consist of a wheel assembly or a slide rail assembly, both of which are also well known in the art.

Conventionally, the track rotates by means of a motor driven sprocket unit at the forward end of the vehicle and idle drive wheels are mounted at the aft end of the vehicle to support the rear end of the track. Sprockets engage a series of lugs integrally formed with the inner surface of the track.

With reference toFIG. 1, the endless body is generally formed of a molded rubber base having, embedded therein, a first layer of reinforcing fabric38extending longitudinally of the track, a series of laterally spaced cord strands40which extend between the first layer of fabric and beneath a rod34, and a second ply36fabric disposed above the rod34. Such arrangement has been shown to allow good track performance and longevity. It is generally believed that an increased amount of fabric contributes these performances. In areas of the track where there is no rod34, it is about at mid-thickness of the track where the fiber of the rubber is the strongest, this line of zero stress in cross section of the track separating the region of compressive stress from that of tensile stress being known as the neutral fiber.

In spite of efforts in this field, there is still a need for a lighter, cost effective track.

SUMMARY OF THE INVENTION

More specifically, there is provided a track for a tracked vehicle, comprising a molded rubber base sandwiching a cord layer, followed by a cross bar and a single layer of ply fabric extending longitudinally of the track.

Other objects, advantages and features of the present invention will become more apparent upon reading of the following non-restrictive description of embodiments thereof, given by way of example only with reference to the accompanying drawings.

DESCRIPTION OF EMBODIMENTS OF THE INVENTION

As shown inFIG. 2, a track10according to an embodiment of the present invention comprises a ground engaging outer side12and an inner side (not seen inFIG. 2).

As seen in the cross-section ofFIG. 3, the track10is formed of a molded rubber base30sandwiching a cord layer32, followed by a cross bar34and a single layer of ply fabric36extending longitudinally of the track.

The cross bar34may consists of a rod as known in the art, made of composite material for example. It is located at spaced intervals along the longitudinal direction of the track beneath the profiles14projecting from the outer side12of the track.

The cord layer32comprises a dense strand arrangement formed of a twist arrangement of strands, comprising for example at least 18 strands per inch for a cord of 1.25 mm. The strands include high strength, light weight materials such as man made fibers, such as Kevlar™, nylon, and polyester fabric for example

The cord layer32extends on the rubber base30and passes beneath the rod34.

The cord layer32may be discontinued at locations of the track where the idler wheels pass.

The ply of fabric36includes woven man-made fibers such as nylon for example.

As shown inFIGS. 4 and 5, the present track is found to necessitate equal or less power, which goes against the current belief in the industry that the greater the amount of fabric in the track composition, the better the performances.

People in the art will appreciate that the present invention provides, in contrast to a track standardly made in the art and including an arrangement of rubber, a first ply fabric, cord, rod, second ply fabric and rubber, a track comprising a single layer of ply fabric, yielding a track of reduced thickness, weight and cost, while maintaining target performances thereof in terms of power and longevity. In particular, the present composition is shown to decrease horse power, increase top speed and improve durability of the track when the latter is driven at high rotational speeds. It has also been found to optimize the so-called neutral fiber50bringing it closer to the outer side of the track.

The present track may be used for a range of tracked vehicles.

Although the present invention has been described hereinabove by way of embodiments thereof, it may be modified, without departing from the nature and teachings of the subject invention as defined in the appended claims.