Transmission shift inhibitor

Claim 1

An automatic reverse control system for a vehicle having a torque producing variable speed engine, manually controlled throttle means for controlling engine speed, traction means for moving the vehicle in forward and reverse directions, manually controlled brake means for selectively stopping movement of the vehicle and shiftable transmission means for selectively transmitting engine torque from the engine to the traction means in one of two directions to cause forward and reverse movement of the vehicle, wherein the automatic reverse control system comprises a. a first fluid operator means for shifting the shiftable transmission means into a forward torque transmitting condition when fluid pressure is applied thereto and for shifting the shiftable transmission means into a reverse torque transmitting condition upon relief of fluid pressure therefrom; b. a second fluid operator means for automatically applying the brake means when fluid pressure is applied thereto; c. automatic fluid pressurized throttle control means for allowing manual control of the throttle means upon application of fluid pressure thereto and for disabling the throttle means to cause the engine to idle when fluid pressure is relieved therefrom; d. first electrically controlled valve means for selectively applying pressurized fluid to said first fluid operator means when electrically energized, and for relieving fluid pressure from said first fluid operator when electrically de-energized; e. second electrically controlled valve means for applying simultaneously fluid pressure to said second fluid operator means and relieving fluid pressure from said automatic fluid pressurized throttle control means when electrically energized and for applying simultaneously fluid pressure to said automatic fluid pressurized throttle control means and relieving fluid pressure from said second fluid operator means when electrically de-energized; and f. automatic vehicle reversIng control means for automatically reversing the vehicle by shifting the shiftable transmission means only after the vehicle has substantially stopped, said automatic vehicle reversing control means including 1. a direction control switch operable between a first state which indicates that a forward vehicle direction is desired and a second state which indicates that a reverse vehicle direction is desired. 2. a speed indication switch operable between a first state which indicates that the vehicle has substantially stopped and a second state which indicates that the vehicle is moving, and 3. circuit means connected with said first and second electrically controlled valve means for controlling the energization of said second electrically controlled valve means whenever said direction control switch is in a state indicative of a desired direction different from the actual direction of movement of the vehicle and for inhibiting a change in the state of energization of said first electrically controlled valve means until said speed indication switch is in said first state whereby the direction of the vehicle may be reversed automatically by changing the state of said direction control switch and said first electrically controlled valve is operative to shift the transmission means only when the vehicle is substantially stopped.