Patent GB-409664-A (GB)
Title: Improvements in or relating to clutch-operating mechanism for motor vehicles
IPC: B60K23/02
Filed: 1932-10-31
Abstract: 409,664. Operating clutches. POLLAK, J. E., 20, Holborn, London.-(Borg & Beck Co. ; 6558, South Menard Avenue, Chicago, U.S.A.). Oct. 31, 1932, No. 30547. [Class 80 (ii).] In an engine-suction servomotor 20 for operating the clutch shaft 17 of a motor vehicle having a main control valve 29, a check valve 33 operable to retard the engaging movement when the clutch elements reach the position of initial engagement, and a bleed valve 38 controlling the speed of the final engaging movement in accordance with the speed of opening of the engine throttle, there is provided also a bleeder-check valve 44 operable to effect a further retardation on violent opening of the throttle. The piston valves 29, 33, 38, and 44 are secured to spring-loaded diaphragms 54, 90, 70, and 100 located in chambers 62, 97, 82, and 109 respectively, the valve 29 controlling communication between pipes 23, 123 leading respectively to the servomotor 20 and the intake manifold 11 of the engine, while the others control an air inlet passage 141. The chambers 62, 82 are connected by pipes 66, 84 to the engine intake 13 as shown in Fig. 2. The chamber 109 communicates through a conduit 131 with the pipe 23 and is in communication with the chamber 97 through a conduit 136. The valve 44 also functions to control communication between conduits 137, 140, the former of which communicates with the pipe 123 while the latter communicates with the conduit 131. With the engine idling, the four valves are maintained by the engine suction in raised position and suction is communicated to the servomotor to maintain the clutch parts disengaged. Upon initial opening of the throttle 14 so as to uncover the pipe 66, the main valve 29 drops, closing direct communication between pipes 23, 123 ; but a restricted auxiliary communication is maintained through the conduits 131, 140, 137 and a restricted annular groove 46 on the valve 44. Air now enters the pipe 23 past the valve 33 and the clutch parts move under the action of the clutch spring towards engaged position. The servomotor pressure being communicated to the chamber 97, the valve 33 drops until a position of balance is reached at which the inflow of air past valve 33 balances the restricted suction, the spring 93 of the valve 33 being so adjusted that this corresponds to initial engagement of the clutch parts. As the throttle is opened further, the pipe 84 is progressively uncovered and the valve 38 drops progressively so as to allow inflow of air past the valve, whereby the clutch parts move to final engaged position at a speed dependent on the speed of opening of the throttle. Finally, the weak spring 105 acts to depress valve 44, closing the conduit 141 except through a restricted annular groove 42 on valve 44, which groove acts to prevent " riding " of the clutch due to suction leakages. If, however, the throttle is opened violently, tending to cause abrupt engagement of the clutch, the valve 44 immediately drops, restricting the inlet of air and thus retarding clutch movement. A valve (not shown), capable of cutting off communication between the pipe 123 and the main valve cylinder while simultaneously opening the pipe 23 to atmosphere so as to render the automatic device inoperative, is controlled by Bowden mechanism 128. Specifications 408,308, 408,309, and 409,674 are referred to.