Patent GB-1065358-A (GB)
Title: Apparatus for operating a mechanical gearbox for motor vehicles
IPC: B60K/
Filed: 1964-10-12
Abstract: 1,065,358. Change-speed gear and clutch control. HANS GLAS G.m.b.H., ISARIAMASCHINENFABRIK. Oct. 12, 1964 [Oct. 15, 1963], No. 41552/64. Headings F2D and F2L. A motor vehicle change-speed gear is shifted manually, with automatic control of the main clutch and the engine throttle valve, or automatically in accordance with vehicle speed and accelerator position, by an electro-hydraulic control system including piston - cylinder arrangements 35/38, 17, and 21/22 which respectively act on a gearshift bar 37 of the gear, to declutch a spring-engaged main clutch 18, and to substantially close the engine throttle valve 25. The automatic clutch control is suitable for starting the vehicle from rest. The main clutch is automatically disengaged at engine idling speed. Gearshifts are effected by a shift bar 37 which is turned to select between 1-2 and 3-4 shift rails by a double-acting rotary piston 36 and moved axially for gear establishment by a double-acting piston 39, both pistons being secured to the shift bar 37. Alternative manual operation is provided by a direct-acting ballmounted lever 40 which also is the sole means for mechanically obtaining reverse against a spring bias. Pressure from a line 4, supplied by a pump 1 and regulated by a spring-loaded regulator valve 12, is controlled by a solenoid valve 5 which when de-energized, is held by a spring 7 in a position venting the line 4 to a return line 11, through port 9. A transistor or other circuit (not described) controlling solenoid valves 5, 30, 33, 34 for automatic shifts has inputs proportional to vehicle speed and accelerator position. For an automatic shift, the solenoid valve 5 is energized, closing the port 9 and causing a buildup of pressure which moves a piston 16 leftwards (Fig. 1) to disengage the main clutch 18 and, via a line 20, to move two spring-returned pistons 23, 24 rightwards to locate an engine throttle valve lever 25, pivoted at 26, in a position corresponding to a low engine speed (e.g. 2000 r.p.m.) which is still above the idling speed. The function of the lower piston 23 is to prevent the throttle closing to idle position during a shift should the driver release the accelerator pedal linkage 27 which is spring- connected to the throttle 25. If this were to occur the clutch would not otherwise re-engage automatically after the shift. When the clutch is fully disengaged, the piston 16 directs pressure through a line 19 to a solenoid valve 30 which, during automatic shifts, is energized to connect the line 19 through a line 32 to the solenoid valves 33, 34 which respectively control admission of pressure to the pistons 36, 39. For first gear, the valves 33, 34 are both energized, supplying pressure fluid to lines 43 and 42. For second, valve 33 only is energized, supplying pressure fluid to lines 43 and 45. For third, valve 34 only is energized, and for fourth, valves 33, 34 are both de-energized. Following the shift, the valves 30 and 5 are de-energized and the clutch springs move the piston 16 rightwards as the clutch re-engages, a throttle 15 having greater resistance to flow in one direction than in the other for regulating the rate of re-engagement so that the system is suitable for starting the vehicle from rest as well as for normal gearshifts on the move.  During manual shifts, a touch-sensitive micro-switch on the lever 40 is closed to block energization of the valve 30 and to energize the valve 5 for automatic clutch and throttle valve control. A drop in engine speed below idling r.p.m. also energizes the valve 5 to de-clutch.