All-wheel steering system and vehicle incorporating the same

A mower vehicle comprising:

• a frame;
• a seat attached to the frame;
• left and right front wheel assemblies, wherein each of the left and right front wheel assemblies comprises:
• a front support arm pivotally coupled to a forward end of the frame and pivotable, relative to the frame, about a vertical axis;
• and a steerable front wheel coupled to the front support arm for rolling engagement with a ground surface;
• left and right rear wheel assemblies, wherein each of the left and right rear wheel assemblies comprises:
• a rear support arm pivotally coupled to an aft end of the frame and also pivotable, relative to the frame, about a vertical axis;
• and a steerable rear wheel coupled to the rear support arm for rolling engagement with the ground surface;
• a cutting deck extending laterally beneath the frame at a location between the front and rear wheels;
• and
• a steering linkage comprising:
• a front linkage assembly connecting the left front wheel assembly to the right front wheel assembly;
• a left wheel tie rod comprising:
• a forward end coupled to the front support arm of the left front wheel assembly;
• and an aft end coupled to the rear support arm of the left rear wheel assembly;
• and
• a right wheel tie rod comprising:
• a forward end coupled to the front support arm of the right front wheel assembly;
• and an aft end coupled to the rear support arm of the right rear wheel assembly;
• a steering actuator attached to the frame and to the steering linkage;
• and
• a steering input device attached to the frame forward of the seat, wherein the steering input device is configured to control the steering actuator.

A mower vehicle comprising:

• a frame;
• a left front wheel assembly and a transversely offset right front wheel assembly both located at or near a forward end of the frame, wherein each of the left and right front wheel assemblies comprises:
• a front support arm pivotally coupled to the frame;
• and a steerable ground-engaging front wheel rotatably coupled to the front support arm;
• a left rear wheel assembly and a transversely offset right rear wheel assembly both located at or near a rearward end of the frame, wherein each of the left and right rear wheel assemblies comprises:
• a rear support arm pivotally coupled to the frame;
• and a steerable ground-engaging rear wheel rotatably coupled to the rear support arm;
• a cutting deck attached to the frame and located generally between the front wheel assemblies and the rear wheel assemblies;
• a steering linkage assembly comprising:
• a rear bell crank pivotally coupled to the frame;
• a left rear tie rod comprising a proximal end pivotally coupled to the rear bell crank, and a distal end pivotally coupled to the left rear wheel assembly, and a right rear tie rod also comprising a proximal end pivotally coupled to the rear bell crank, and a distal end pivotally coupled to the right rear wheel assembly;
• a front steering lever arm pivotally attached to the frame;
• a left front tie rod comprising a proximal end pivotally coupled to the front steering lever arm, and a distal end pivotally coupled to the left front wheel assembly, and a right front tie rod also comprising a proximal end pivotally coupled to the front steering lever arm, and a distal end pivotally coupled to the right front wheel assembly;
• and
• a longitudinal tie rod, wherein an aft end of the longitudinal tie rod is pivotally attached to the rear bell crank and a forward end of the longitudinal tie rod is pivotally attached to the front steering lever arm;
• a steering input device coupled to the frame to control vehicle direction;
• and
• a steering actuator attached to the frame and to the steering linkage assembly, the steering actuator responsive to manipulation of the steering input device.