Patent ID: 7594557

Claim:
A suspension assembly for a snowmobile, the snowmobile having a chassis enclosing a drive system for rotatably driving a closed-loop track in a rear tunnel of the snowmobile, the suspension assembly comprising: at least one elongated ground contact supporting rotational travel of the closed loop track; a swing arm angularly disposed in the closed-loop track, the swing arm including a front end portion that is pivotably coupled to the tunnel and a rear end portion coupled to the at least one ground contact; a front resilient member disposed in the closed-loop track and having an upper end pivotally coupled to the front end portion of the swing arm and a lower end pivotally coupled to the at least one ground contact, wherein the front resilient member biases against displacement between the front end portion of the swing arm and the at least one ground contact during suspension assembly travel; and a rear resilient member disposed in the closed-loop track and having an upper end pivotally coupled to the tunnel and a lower end pivotally coupled to the rear end portion of the swing arm, wherein the rear resilient member biases against displacement between the swing arm and the tunnel during suspension assembly travel; a tensioner disposed in the closed-loop track and coupling the rear end portion of the swing arm to the at least one ground contact, the tensioner being extendable and retractable in a fore and aft direction during movement of the suspension assembly; wherein the assembly is arranged to maintain the closed loop track at a generally uniform tension during both vertical and horizontal travel of the closed-loop track during suspension system travel; and a front elongated cross shaft extending transversely through the closed-loop track and coupled to the chassis, wherein the front end portion of the swing arm is rotatably coupled to the chassis via the front elongated cross shaft, and the front elongated cross shaft provides a centerline of rotation for the swing arm.