Patent GB-415419-A (GB)
Title: Improvements in clutch control mechanism
IPC: F16D23/10
Filed: 1933-02-23
Abstract: 415,419. Operating clutches. BENDIX AVIATION CORPORATION, 105, West Adams Street, Chicago, U.S.A. Feb. 23, 1933, Nos. 5549 and 5550. Convention dates, Feb. 24, 1932. [Class 80 (ii).] In control mechanism for the power-operated clutch of a motor vehicle including means which prevent clutch engagement unless a predetermined speed relation exists between a driving and a driven element of the vehicle, the said means comprises a solenoid having a soft-iron core and a pair of differentially-wound windings energized by electrical generators driven from the driving and driven elements of the vehicle respectively. As shown in Fig. 1, the working chamber of a servomotor 121, the piston of which is connected to the clutch pedal 120, is adapted to be put alternatively into communication with the engine induction manifold 106 or with the atmosphere through a conduit 128 under the control of a three-way valve 122 connected to the accelerator pedal 114, the connection including a flexible wire cable 141 and the arrangement being such that as the accelerator is released or depressed the clutch is disengaged or engaged respectively. The windings 163 and 164 of a solenoid 160 are connected respectively to an engine-driven generator 165 and to a generator 172 driven from the driven clutch member, the windings being differentially wound and the currents therein flowing in opposite directions, while the core 162 is operatively connected to the cable 141. The arrangement is such that when the clutch members are rotating at substantially the same speed, the effective flux in the solenoid is nil and the valve 122 is thus freed from restraint, while if the speeds are not substantially the same the core is drawn up to maintain the valve 122 in the position corresponding to clutch disengagement. A switch 184 is so controlled by the gear lever 107<a> that the solenoid is effective only in high gear. The first portion of the engaging stroke of the servomotor is relatively rapid, due to the provision of passages in the piston rod, the speed of the final portion of the stroke being controlled by an adjustable bleed valve 129 and a Bowdencontrolled valve 186. The three-way valve 122 comprises a spring-loaded grooved piston 138, Fig. 3, adapted to put the pipe 128 into communication either with a port 149 connected to the manifold 106 or with the atmosphere through ports 150 and filtering material 151<a>. The piston has a small amount of axial play on a sleeve 152 which is carried by the valve rod 142 and which is provided with a longitudinal passage 155 normally unobstructed at the right-hand end and controlled at the lefthand end by a valve member 154 formed on the sleeve 152, whereby the formation of a partial vacuum at the right-hand end of the valve is prevented, and an adjustable aperture 156 is provided in the right-hand end of the valve casing so as to prevent any dashpot action of the valve. In a modification, the core of the solenoid, instead of affecting the valve 122, forms a valve controlling communication between the non-suction end of the servomotor and an outlet to atmosphere controlled by an adjustable bleed valve and a Bowden-controlled valve. Means may be provided whereby the circuit of the winding 163 is closed only above a predetermined engine speed, whereby, with the vehicle in motion, clutch engagement is prevented unless the engine speed exceeds the predetermined amount.