A hydrostatic vehicle transmission and control for automatically controlling vehicle operation in accordance with pre-selected operator settings. The hydrostatic transmission automatically adjusts to operational conditions of the vehicle to obtain the pre-selected function and automatically adjusts the vehicle transmission until the preselected operational conditions can be obtained.

A steering control system is disclosed for use on a dual path, hydrostatic drive vehicle. The steering control system includes a steering signal generator, the steering signal representing commanded steering ratio and direction. The system senses vehicle direction and steering direction and generates an electrical switch signal having a first or second condition, depending upon which transmission must have its speed reduced to achieve the desired vehicle orientation. The steering signal and the main speed command signal are multiplied to generate a speed modification signal and an electrical switch transmits the modification signal to one transmission or the other depending upon whether the switch signal is in the first or second condition. The disclosed steering system permits use of a T-handle control, for both speed and steering, such that vehicle orientation may be maintained generally perpendicular to handle orientation for both forward and reverse vehicle travel.

An all seasons vehicle has a hydraulic control circuit that is used to make the vehicle highly maneuverable in which the rear treads are controllable through a speed control driving or controlling the speed of each of the hydraulic motors from a pair of hydraulic pumps connected to the motors in proportion to the position of a control element that is changed through the steering wheel of the vehicle. The control over the hydraulic motors may be increased or decreased by overriding the position of the control element and increasing the hydraulic flow of fluid to one motor or the other without interfering with the direction being imparted to the vehicle.

The invention comprehends a remote control mechanism comprising push-pull control links operatively connected at one end to spaced locations of a beam, said beam being pivotally movable about mutually displaced first and second axes, said spaced locations of said beam moving equally in the same direction upon pivoting of said beam about said first axis, said spaced locations of said beam moving in opposite directions relative to said control links upon pivoting of said beam about said second axis, one of said axes being fixed and the other axis rotating about said one axis when said beam is pivoted about said one axis, paired coincident movement of said control links being complementary to both said spaced locations of said beam moving equally in said same direction, and differential relative movement of said control links being complementary to said spaced locations of said beam moving in said opposite directions.

A hydraulically driven utility vehicle comprising hydraulically operated, reversible propulsion means on each side of said vehicle, a source of hydraulic fluid contained on said vehicle, a first hydraulic flow control valve coupled between said hydraulic source and said propulsion means on one side of said vehicle, a second hydraulic flow control valve coupled between said hydraulic source and said propulsion means on the other side of said vehicle, and a control stick hydraulically coupled to said first and second flow control valves for controlling vehicle speed and direction by selectively positioning said first and second control valves whereby movement of said stick causes said flow control valves to direct hydraulic fluid from said source to said propulsion means to control speed and steering of said vehicle.