Improvements in and relating to Electro-Hydraulic Control devices for Overriding the Controls at the Main Driving Position in Motor Vehicles, having Automatic Gear Shifting Mechanism, from a Second Driving Position

摘要

1,164,419. Controlling motor vehicles. ZAHNRADFABRIK FRIEDRICHSHAFEN A.G. 3 April, 1968 [5 April, 1967], No. 15990/68. Heading B7H. In an electro-hydraulic control system for overriding the controls at the main driving position in a military or construction vehicle having automatic change-speed gearing by indirectly actuating the main control members from a second driving position, the accelerator pedal 20, brake pedal 30 and steering wheel 40 at the main driving position are each connected to the piston of a respective double-acting hydraulic cylinder 21, 31, 41 one or both chambers of which is selectively connected according to the position of a control lever 79 at the second driving position either with the pressure supply line 16 or the return line 17 of a common oil pressure supply circuit comprising a motordriven pump 11, an oil reservoir 13, an oil filter 14, a pressure relief valve 15 and an hydraulic accumulator 19. Electromagnetic valves 26, 27, 36, 37, 46, 47 connect the chambers of each cylinder 21, 31, 41 to the supply and return lines 16, 17 depending on actuation of switches 71, 72, 73, 74, 75, 76, 77 by the control lever 79. A switch 78 on the lever 79 is depressed to energize the pump motor 12 and the lever is displaceable rearwardly to actuate the switches 73, 74 associated with the brake pedal cylinder 31, forwardly to actuate the switches 71, 72 associated with the accelerator pedal cylinder 21 and transversely in either direction to actuate the switches 75, 76, 77 associated with the steering wheel cylinder 41. The switches are arranged such that when the lever 79 occupies a central neutral position both chambers of the cylinder 41 are connected to the return line 17 so that the steering wheel 40 is freely actuable by the driver at the main driving position and one chamber of each cylinder is connected to the supply line 16 so that the brake and accelerator pedals 20, 30 can be depressed against a restoring force exerted by the fluid pressure. When the lever 79 is moved in any direction it first reaches a blocking position in which it is releasably held by resilient latch means 89, 90, 99, 100 and wherein both chambers of the cylinder associated with the control member influenced by movement in that direction are pressurized to prevent movement of that control member by the driver at the main driving position. Further movement of the lever 79 for venting one chamber of the cylinder to adjust the position of the control member must be made against spring loading 81, 82, 83, 84 tending to restore the lever to the blocking position. The lever 79 can be moved simultaneously in both planes for simultaneous blocking or control of steering and acceleration or braking, but in endless-track vehicles steered by differential driving brake control is permitted only in the straight-ahead position to avoid overloading the transmission.