Patent GB-449545-A (GB)
Title: Improvements in clutch control mechanism for automobiles
IPC: F16D48/06
Filed: 1934-12-28
Abstract: 449,545. Operating clutches. BENDIX AVIATION CORPORATION, 105, West Adams Street, Chicago, U.S.A. Dec. 28, 1934, No. 37148. Convention date, Dec. 29, 1933. [Class 80 (ii)] [See also Group XXIX] 'Controlling means for an engine-suction servomotor 27, operating the clutch of a motor vehicle, comprises a sleeve valve 31, which is slidable in a casing 30 and is actuated by a cam 38 secured on the spindle 13 of the engine throttle valve 12, and a piston valve 32 which is arranged within the valve 31 and is actuated by a spring-loaded servomotor 47 which is in communication with the servo 27, the arrangement being such that the movement of the clutch elements towards engagement is checked at a point the position of which is progressively later in accordance with the progressively more rapid opening of the engine throttle. Circumferentially - spaced ports 68 in the valve 31, communicating respectively with a passage 55 connected by a pipe 57 to the engine intake manifold 10 and with a chamber 61, are adapted to be connected by an annular groove 70 on the valve 32, while circumferentially - spaced ports 69 in the valve 31, communicating respectively with the chamber 61 and with a chamber 74, are adapted to be connected by an annular groove 71 on the valve 32. The chamber 61 is connected to the servo 27 by a pipe 67 and to the servo 47 by a passage 62. The chamber 74 has an adjustable leak 77 to the atmosphere and communicates with a chamber 75 through a valve 80 actuated by a servomotor 96 which is loaded by a weak spring and is connected to the chamber 61 by a passage 93. The chamber 75 is open to the atmosphere through a port 76. The movable member of the servo 27 is connected by a cable 23 to an arm 21 fixed on the clutch shaft 20, and a clutch pedal 19, loose on the shaft 20, has a lug 22 co-operating with the arm 21. With the accelerator released, the cam 38 maintains the valve 31 in its lowest position, with the ports 68 registering with the groove 70. The servo 27 is thus connected to the manifold 10 and the clutch is disengaged. The servos 47 and 96 are also energized, whereby the valve 32 is maintained in its lowest position and the valve 80 is opened. Upon now depressing the accelerator, the valve 31 rises, under the action of a spring 36, bringing the ports 68 out of register with the groove 70 and bringing the ports 69 into register with the groove 71. The valve 80 being open, air quickly enters the servo 27, allowing the clutch parts to move quickly towards engagement. Upon partial clutch engagement and the resulting increase of pressure in the servo 47, the valve 32 rises until the inflow of air is cut off, whereby clutch engagement is checked. The point at which engagement is checked is dependent on the speed of opening of the throttle, occurring substantially at the point of initial engagement when the throttle is opened slowly and occuring later in the stroke as the throttle is opened more rapidly. If, however, the throttle is opened excessively quickly, the valve 80 closes, thus restricting the inflow of air. The speed of the final part of the engaging movement is determined by the subsequent speed of opening of the throttle. The cam 38 is such that the valve 31 reaches its uppermost position at substantially half-throttle. As the throttle opening is reduced, from half-throttle, the clutch is progressively released until, at the final release of the accelerator, the clutch is already substantially disengaged. The passage 55 is controlled by an electromagnetic spring- closed valve 100, the winding of which is in series with the ignition switch 105 and with a main control switch 111, other control switches 120, 129, 133 and 138 being arranged in parallel. The switch 120 is normally closed but is opened by a selector bar 127 when high gear is engaged, the switch 129 is in the form of a button on the gear lever 128, and the switch 138 is operated by the speedometer so as to be closed only when the vehicle speed is below a predetermined amount. Thus, with the switch 111 open, the automatic mechanism is inoperative. With the switch 111 closed, the mechanism is operative except when the vehicle is in high gear above the predetermined speed. This speed control is, however, rendered ineffective by closing the switch 133 or the button switch 129.