Patent GB-429264-A (GB)
Title: Improvements in or relating to clutch actuating mechanism
IPC: B60K23/02
Filed: 1933-11-18
Abstract: 429,264. Operating clutches. BENDIX AVIATION CORPORATION, 105, West Adams Street, Chicago, U.S.A. Nov. 18, 1933, Nos. 32182, 32183, and 32184. Convention dates, Nov. 19, 1932, Dec. 1, 1932, and Aug. 18, 1933. [Class 80 (ii)] The rate of engagement of the power - disengaged clutch of a motor vehicle is controlled by means in the mechanical connection between the power device and the clutch. The power device is an engine - suction servomotor. In the form shown in Figs. 1 and 2, the connection between the servo piston 78 and the clutch lever 38 comprises a spring 86 arranged between the flanged ends of the piston rod and a rod 92, which latter is connected to the lever 38 and has length-adjusting means 93, the spring 86 being weaker than the clutch spring. The servomotor is controlled by a piston valve 44 which is linked to the accelerator 26 and which is provided with an annular recess 52 and a longitudinal slot 58 which serve to put the servo chamber 401 into communication with the engine intake manifold 12 or with the atmosphere according as the accelerator is released or depressed respectively. A cut-out valve 64, operable by Bowden mechanism 70, is adapted to render the servomotor inoperative. Thus, on release of the accelerator, the clutch is disengaged, air entering the servo chamber 40<11> through a check valve 102 and the spring 86 being compressed. On depressing the accelerator, the clutch engages, the first part of the engaging stroke being relatively rapid, due to the efflux of air from the chamber 40<11> through a slot 81 in the rod 80, the length of the rod 92 being so adjusted that the slot 81 is closed when the clutch plates contact. The subsequent rate of movement of the piston 78 is dependent on the degree of depression of the accelerator, being controlled by the bleed of air from the chamber 40<11> through a conduit 62 and a tapered longitudinal slot, (not shown), in the valve 44. When the clutch plates contact with a predetermined pressure, the spring 86 expands and air can then also pass from the chamber 40<11> through the hollow piston rod 80 and the interstices between the coils of the spring, whereby the remainder of the engaging stroke takes place at a progressively increasing rate. In a modification, the expansion of the spring 86 serves to open an adjustable spring- loaded valve normally closing the hollow rod 80 ; in this form the bleed conduit 62 may be dispensed with, leakage and the momentum of the parts being relied on to effect the intermediate part of the engaging stroke. In the form shown in Figs. 7 and 8, the servomotor is controlled by a piston valve 218 which is arranged to be moved positively by the accelerator, on release of the latter, so as to connect the servo to the intake manifold, but which, on depression of the accelerator, is moved to connect the servo to atmosphere by the engine suction acting on the end of the valve through a passage 228. The first part of the engaging stroke of the servo piston, during which the connecting spring 254 remains compressed, is relatively rapid, due to the bleed of air through the hollow piston rod and holes 242, 258. But, after the clutch plates have contacted, the spring 254 expands and the rate of engagement is progressively lowered due to the conical sleeve part 256. In the form shown in Figs. 9 and 12, a member 374 insulated from but frictionally mounted on the piston rod 334 co-operates with the coupling member 382 and with an insulated clip 380 secured to the member 382 in such a way that during the first part of the engaging stroke, when the spring 384 remains compressed, the members 374, 382 are separated and a solenoid-controlled valve 368 remains open so as to allow rapid bleed of air from the servo chamber 364, while, after the clutch plates have contacted and the spring 384 expands, the members 374, 382 contact and complete the circuit of the solenoid 372, whereby the valve 368 is closed and the subsequent rate of clutch engagement is dependent on the degree of opening of an acceleratoroperated bleed valve 362. Specification 408,309 is referred to. The Specification as open to inspection under Sect. 91 comprised also the subject-matter of Specification 431,971. This subject-matter does not appear in the Specification as accepted.