Patent ID: 8016068

Claim:
A tandem drive arrangement including one or more independently driven wheels arranged in a tandem configuration along a tandem beam, the tandem beam rotatably connected to a frame of a machine, the tandem drive arrangement further comprising: at least one hydrostatic motor operating at least one of the one or more independently driven wheels; a hydraulic system having a variable displacement hydraulic pump connected to an output of an engine, the hydraulic system including: a valve disposed to receive a flow of hydraulic fluid from the variable displacement hydraulic pump; a first conduit connected to the valve and disposed to selectively receive a flow of hydraulic fluid therefrom; a drain passage connected to a reservoir; a second conduit connected to the valve and disposed to be selectively fluidly connected to the drain passage; a motor supply conduit and a motor return conduit connected to the at least one hydrostatic motor and arranged to provide a flow of driving fluid therethrough; a first junction fluidly connecting the motor supply conduit with the first conduit; a second junction fluidly connecting the motor return conduit with the second conduit; a first fluid port arranged to provide fluid to one side of the linear actuator and being connected to the first junction; and a second fluid port arranged to provide fluid to another side of the linear actuator and being connected to the second junction; a chassis pin extending from the frame; an actuator operating to selectively impart a rotating moment to the tandem beam, the rotating moment tending to rotate the tandem beam, wherein the actuator is a linear actuator rotatably connected at one end thereof to the chassis pin, and rotatably connected at another end thereof to the beam at a drive pin, wherein the linear actuator operates to impart the rotating moment when the linear actuator extends and when the linear actuator retracts; wherein rotation, due to being driven, of the one or more independently driven wheels causes a torque imbalance tending to rotate the tandem beam, the torque imbalance being counteracted by the rotating moment imparted by the actuator.