Patent GB-1006968-A (GB)
Title: Automatic clutch controlling apparatus principally for automobiles
IPC: F16D48/06
Filed: 1964-08-31
Abstract: 1,006,968. Clutch control. DAIKIN SEISAKUSHO KABUSHIKI KAISHA. Aug. 31, 1964 [Dec. 19, 1963; March 25, 1964], No. 35498/64. Heading F2L. A vehicle clutch operating system includes a vacuum servomotor 1 connected by a pipeline 69 to the engine manifold M, and an associated follow-up control valve 2 connected to the carburettor Venturi C so as to be responsive to engine speed. As shown the servomotor has a central diaphragm 11 forming chambers 12, 13 and connected on one side to a plunger 16 operating the piston 4 of an hydraulic actuator connected by a line 6 to an actuator 7, 9 operating the clutch release levers 10. The opposite side of diaphragm 11 carries an open-ended tube 18 with a vent 20, the open-end co-operating with the control valve member 34 which is connected by a rod 32 to a second diaphragm 27, one side of which is vented to atmosphere through a port 31 while the other side is connected to the carburettor C by a line 83. The system includes a suction chamber 67 with an associated check valve 68 and a main valve 46 incorporating an air suction valve 72, together with a free path valve 58 and check valve 82. The electrical circuit includes a switch 43 which is closed by the driver gripping the gear change lever 42, and a second switch 54 which is closed when the gear lever is positioned in the low speed or reverse, and is opened when the lever is in the high speed range. Operation.-With the engine turned off the servomotor 1 and control valve 2 are positioned as shown with the clutch fully engaged. If the engine is started servo-chamber 13 is connected to suction chamber 67 and diaphragm 11 moves to the left to disengage the clutch. At the same time diaphragm 27 is also moved to the left by a loading spring 37. Operation of gear lever 42 causes the admission of air to servo-chamber 12 to move diaphragm 11 to the left, but upon completion of gear shift and release of lever 42 air passes to chamber 13 to centre diaphragm 11 and cause the open end of tube 18 to engage control valve element 34. Operation of the accelerator pedal results in a pressure drop in the carburettor C so that diaphragm 27 moves to the right against the force of spring 37 through a distance proportional to the pressure drop, the servo-diaphragm 11 moving in the same direction to engage the clutch. The follow-up control period may be varied by adjusting a screw connection between the servomotor 1 and the control valve 2, and the rate of clutch engagement may be varied by adjusting the setting of spring 37. If the driver moves lever 42 for an up-shift the pressures in servo-chambers 12, 13 are first balanced and then diaphragm 27 and valve member 34 are moved to the right for rapid release and re-engagement of the clutch. The following optional features are also described: (a) A rapid starting device fitted between the engine manifold M and valve 58, Fig. 4 (not shown. (b) A compensating valve fitted between the accelerator pedal and control valve 2 to reduce the time lag in clutch operation through slow operation of the accelerator pedal, Fig. 5 (not shown). (c) A variable throttle valve, operated automatically or manually, to modify the effect of reduced pressure in the carburettor Venturi on the control valve 2, Figs. 6-8 (not shown). (d) A valve fitted between the carburettor and control valve 2 for cold-weather starting, Fig. 9 (not shown). (e) An emergency switch fitted in the electric circuit to prevent clutch disengagement if the belt driving the dynamo and cooling fan breaks, Fig. 10 (not shown). (f) A relay to ensure clutch disengagement upon rapid brake application, Fig. 11 (not shown).