Patent ID: 7478688

Claim:
A suspension system for a track assembly of a track laying vehicle, the track assembly having a lower front idler wheel, a lower rear idler wheel, an upper drive wheel, a support link, a plurality of lower support wheels arranged between the idler wheels and mounted on the support link, and an endless belt mounted around the wheels, the front and rear idler wheels being separated by a length L, the track assembly defining an upper belt plane which is tangent to one of the idler wheels and the drive wheel and defining a lower belt plane which is tangent to the front idler wheel and the rear idler wheel, and the vehicle having a center of gravity located a distance H above the lower belt plane, the suspension system comprising: a suspension member pivotal about a pivot axis which is fixed with respect to a frame of the vehicle, the suspension member having a first end coupled to the support link by a resilient member, the suspension member having a second end pivotally coupled to an axle pin defining a rotation axis of one of said idler wheels, and pivotally coupled to an end of the support link, and the rotation axis and the pivot axis defining a suspension axis extending therebetween, the suspension axis and the upper belt plane defining a first angle θ, the suspension axis and the lower belt plane defining a second angle φ, such that (sin φ−sin θ)÷(H/L×cos φ)=1.