A utility vehicle, comprising:
- an elongated support frame extending between first and second frame ends and having left and right sides;
- a pair of left and right first end wheels, said left first wheel being positioned toward said left side of said frame first end, and said right first wheel being positioned toward said right side of said frame first end;
- a pair of left and right fluid-powered rotary actuators, said left actuator being positioned toward said left side of said frame first end, and said right actuator being positioned toward said right side of said frame first end, each of said actuators including:
- a body rigidly attached to said frame, said body having a longitudinal axis, and body upper and lower ends;
- first and second fluid ports for introducing pressurized fluid within said body at longitudinally spaced-apart locations;
- a drive member extending generally longitudinally and co-axially within said body, said drive member being supported for rotational movement relative to said body, said drive member having an attachment portion at said body lower end;
- a piston mounted within said body with said first port in fluid communication with one side thereof and said second port in fluid communication with an opposite side thereof to produce reciprocal longitudinal movement of said piston within said body in response to selective application of pressurized fluid to said first and second ports;
- and
- a torque-transmitting member mounted for reciprocal longitudinal movement within said body, said torque-transmitting member engaging said body and said drive member to translate longitudinal movement of said piston toward said body upper end into rotational movement of said drive member relative to said body in a first rotational direction, and longitudinal movement of said piston toward said body lower end into rotational movement of said drive member relative to said body in a second rotational direction opposite said first rotational direction;
- a pair of left and right wheel brackets, said left wheel bracket being mounted to said attachment portion of said left actuator for rotation therewith, and said right wheel bracket being mounted to said attachment portion of said right actuator for rotation therewith, said left first wheel being rotatably mounted to said left first wheel bracket in a position to rollingly support said frame, and said right first wheel being rotatably mounted to said right wheel bracket in a position to rollingly support said frame, said left and right wheel brackets being rotatable by said left and right actuators to turn said left and right first wheels to steer said frame to the left or right;
- a motor supported by one of said left or right wheel brackets and drivably coupled to a corresponding one of said left or right first wheels to provide rotational drive power thereto;
- a fluid-control valve;
- a source of pressurized fluid connected to said fluid-control valve;
- fluid conduit interconnecting said first and second ports of said left and right actuators for series operation, said fluid conduit including a first conduit connecting said fluid-control valve to said first port of said left actuator, a second conduit connecting said second port of said left actuator to said first port of said right actuator, and a third conduit connecting said second port of said right actuator to said fluid-control valve, said fluid-control valve being operable to selectively apply pressurized fluid to said first conduit or said third conduit and hence to said pistons of said left and right actuators to simultaneously rotate said drive members and thereby turn said left and right first wheels in unison and in substantially equal angular amounts to steer said frame to the left or right;
- and
- at least one second end wheel mounted to said frame toward said frame second end in position to rollingly support said frame.