GB940384A - Improvements in or relating to fluid pressure control means for friction clutches - Google Patents

Abstract

940,384. Fluid-pressure servomotor control systems. AUTOMOTIVE PRODUCTS CO. Ltd. Dec. 22, 1959; [Dec. 30,1958; Nov. 27,1959], Nos. 40473/59 (Divided out of 938, 561) and 40474/59. Heading G3P. [Also in Division F2] The subject-matter of this Specification is similar to that described in Specification 938,561 but in the conduit to the power device there is included a solenoid-actuated three-way valve operated either by a manual switch or automatically when shifting the gear lever; the valve either connects the power device with the speed responsive valve or with the vacuum or pressure reservoir. In a modification, the conduit 48 to the power device 34 contains a valve device 91 comprising two closures 102, 103 actuable by a diaphragm 92, the closures being normally in the position shown; the upper closure 102 controls the communication between conduit 48 and another conduit 116, which as shown may be open to atmosphere 125 or to the vacuum reservoir 39 via two solenoid actuated actuated valves 112, 127. The conduit 116 has a branch 128 leading to a power device 129 and another conduit 132 from a chamber 117 in valve 112 leads to another power-device 133,both devices 129,133 acting oppositely on the engine throttle 131. A vacuum operated switch 134 is connected to conduit 116 and another switch 137 is mounted in the clutch and only closes when the driven plate 21 is running faster than the pressure plate 18. Upon initiating a gear change, a switch 136, in the gear lever knob e.g., is closed and the solenoid valve 112 is energized to apply suction to the diaphragm 92 thereby seating closure 103 and opening closure 102 to connect the device 34 to vacuum via conduit 116 and disengage the clutch; the switch 134 is also closed and the power device 129 reduces the throttle opening. Should the engine speed not fall sufficiently to bring the speed of the pressure plate below that of the driven plate then upon the opening of a switch 136 the device 134 is reconnected to atmosphere to re-engage the clutch; if the speed of the pressure plate falls below that of the driven plate, the switch 137 closes and solenoid valve 127 is energized to maintain the application of vacuum in the device 34 when the gear change is completed and the solenoid valve 112 is de-energized. Vacuum is also applied to power device 133 to open the throttle until the switch 137 opens and enables the clutch to re-engage.