Patent ID: 6634445
Filing Date: 2003-10-21
Classification: B60G

Abstract:
A skid steer vehicle comprising:a chassis having a left side and a right side; an engine coupled to the chassis; first and second variable displacement hydraulic pumps coupled to the engine to provide two separately controllable sources of hydraulic fluid under pressure; four non-steerable and ground-engaging wheels coupled to the chassis to drive the vehicle over the ground, wherein the wheels are disposed two on each side of the chassis in a fore-and-aft relation; four control arms pivotally coupled to the chassis and coupled to the four wheels to permit the wheels to pivot at least in a vertical direction with respect to the chassis; at least two hydraulic motors for driving the wheels wherein at least one motor is driven by fluid from the first pump and in turn drives the wheels on the left side of the chassis and at least another motor is driven by fluid from the second pump and in turn drives the wheels on the right side of the chassis; four hydraulic cylinders, each cylinder operably coupled to one of the wheels to control at least the vertical position of the wheels with respect to the chassis; a speed sensing means to provide a signal indicative of the speed of the vehicle over the ground; and an electronic controller coupled to the speed sensing means and to the hydraulic cylinders that is configured to lock the four wheels in a vertical position with respect to the chassis when the vehicle falls below a predetermined speed.