Suspension system for hitch assembly

Claim 2

In combination, a tractor having a frame and a single axle housing rigidly carried by said frame, driving wheels rotatably mounted on opposite ends of said axle housing, a trailing unit having wheel means at the rear end thereof, a hitch assembly including a steering frame supporting the forward end of the trailing unit on the tractor above the axle housing for relative steering movement about a vertical axis and for relative oscillation about a horizontal axis extending longitudinally of the tractor, the improvement of a suspension system located below said steering frame for connectinG the hitch assembly to said tractor and for controlling bounce and pitch type movement of said trailing unit while the latter is being pulled by said tractor, said suspension system comprising a sub-frame connected to said steering frame along said horizontal axis, a linkage connecting the sub-frame to the tractor, said linkage including front and rear links having their upper ends respectively pivotally connected to the sub-frame for rotation about first and second horizontally spaced pivot axes, the lower ends of said front and rear links being respectively pivotally connected to said tractor for rotation about third and fourth pivot axes, the front and rear links being so arranged that a straight line passing through the centers of the first and third pivot axes on the front link intersects a straight line passing through the centers of the second and fourth pivot axes on the rear link at a point located to the rear of said axle housing, and spring means connected between said sub-frame and the tractor for cushioning said bounce and pitch type movement of the trailing unit.

Claim 3

In combination, a tractor having a frame and a single axle housing rigidly carried by said frame, driving wheels rotatably mounted on opposite ends of said axle housing, a trailing unit having wheel means at the rear end thereof, a hitch assembly including a steering frame supporting the forward end of the trailing unit on the tractor above the axle housing for relative steering movement about a vertical axis and for relative oscillation about a horizontal axis extending longitudinally of the tractor, the improvement of a suspension system located below said steering frame for connecting the hitch assembly to said tractor and for controlling bounce and pitch type movement of said trailing unit while the latter is being pulled by said tractor, said suspension system comprising a sub-frame connected to said steering frame along said horizontal axis, a linkage connecting the sub-frame to the tractor, said linkage including front and rear links having their upper ends respectively pivotally connected to the sub-frame for rotation about first and second horizontally spaced pivot axes, the lower ends of said front and rear links being respectively pivotally connected to said tractor for rotation about third and fourth pivot axes, the front and rear links being so arranged that a straight line passing through the centers of the pivot axes on the first link intersects a straight line passing through the centers of the pivot axes on the rear link at a point located to the rear of and below said axle housing, and a pair of cylinder means pivotally connected between said sub-frame and the axle housing for cushioning said bounce and pitch type movement of the trailing unit and being located along a transverse plane that passes between said first and third pivot axes of the front link.

Claim 4

In combination, a tractor having a frame and a single axle housing rigidly carried by said frame, driving wheels rotatably mounted on opposite ends of said axle housing, a trailing unit having wheel means at the rear end thereof, a hitch assembly including a steering frame supporting the forward end of the trailing unit on the tractor above the axle housing for relative steering movement about a vertical axis and for relative oscillation about a horizontal axis extending longitudinally of the tractor, the improvement of a suspension system located below said steering frame for connecting the hitch assembly to said tractor and for controlling bounce and pitch type movement of said trailing unit while the latter is being pulled by said tractor, said suspension system comprising a sub-frame connected to said steering frame along said horizontal axis, a linkage connecting the sub-frame to the tractor, said linkage including front and rear links having their upper ends respectively pivotally connected to the sub-frame for rotation about first and second horizontally spaced pivot axes, the lower ends of said front and rear links being respectively pivotally connected to said tractor for rotation about third and fourth pivot axes, the front and rear links being so arranged that a straight line passing through the centers of the pivot axes on the first link intersects a straight line passing through the centers of the pivot axes on the rear link at a point located to the rear of and below said axle housing, and a pair of cylinder means pivotally connected between said sub-frame and the axle housing for cushioning said bounce and pitch type movement of the trailing unit and being located along a transverse plane that passes between said first and third pivot axes of the front link.