Patent ID: 7066294

Claim:
A hydraulically driven and steered vehicle, comprising: a pair of axles differentially connected to each other; a prime mover; a speed control operation device for controlling the traveling speed of the vehicle and switching the traveling direction of the vehicle between forward and backward; a traveling HST including a variable displacement hydraulic traveling pump drivingly connected to said prime mover, said traveling pump having a movable swash plate operatively connected to said speed control operation device, and a hydraulic traveling motor fluidly connected to said traveling pump and drivingly connected to said axles so as to drive said axles at the same various speed in the same forward or backward direction; a steering operation device for turning the vehicle; a steering HST including a variable displacement hydraulic steering pump drivingly connected to said prime mover, said steering pump having a movable swash plate, and a hydraulic steering motor fluidly connected to said steering pump and drivingly connected to said axles so as to drive said axles differentially; and a steering control linkage operatively interposed between said steering operation device and said swash plate of said steering pump, said steering control linkage including a hydraulic actuator constituting a reverse steering logic mechanism, said hydraulic actuator being switched between a forward traveling state and a backward traveling state, wherein the relation of movement direction of said swash plate of said steering pump to movement direction of said steering operation device is reversed according to switching of said hydraulic actuator between said forward traveling state and said backward traveling state, and a hydraulic valve for supplying fluid to said hydraulic actuator, said hydraulic valve being controlled so as to set said hydraulic actuator to either said forward traveling state or backward traveling state depending upon whether said speed control operation device is operated for forward traveling or backward traveling.