Patent GB-531901-A (GB)
Title: Improvements in or relating to clutch operating means
Filed: 1939-07-11
Abstract: 531,901. Clutch operating means. BENDIX WESTINGHOUSE AUTOMOTIVE AIR BRAKE CO. July 11, 1939, No. 20204. Convention date, July 12, 1938. [Class 80 (ii)] [Also in Group XXIX] In a control system for a servomotor 8 actuating the clutch 10 of a motor-vehicle, deenergization of the motor to cause clutch engagement is controlled by inter-connected valves 49, 66 of which the control valve 49 on operation of the master valve 66 effects partial de-energization of the motor and thereafter permits complete de-energization in accordance with the speed of the vehicle engine. The clutch is thus moved rapidly to the point of initial engagement and then gradually in accordance with engine speed. In one form, Fig. 1, the master valve 66 is controlled from the accelerator pedal 80 and the control valve 49 by an engine-driven governor 61. Pressure fluid from a reservoir 26 passes to the motor 8 by way of conduits 27, 29 and a valve 122 controlling communication between chambers 25, 128. The valve 122, and further valves controlling conduits 47, 69, leading to and from the valves 49, 66, are controlled from the shifter bars 16 ... 19 of the gear-shifting mechanism. The shifter bars are so connected that movement of the inter-connected bars 16, 18 in one or other direction will establish first or reverse gear ratio, while movement of the inter-connected bars 17, 19 in one or other direction will establish third or second gear ratio. The bars 18, 19 each have three notches adapted to register with the spring-controlled plunger 30 or 42 in the neutral position and the two gear positions, while a single notch in the bar 17 registers with the plunger 74 in the neutral position only. The plungers 30, 42 have bores 38, 45 leading respectively to a chamber 28 and to the conduit 47, and are controlled by valves 123, 23 each connected to the valve 122 or 22. The plunger 74 is connected by a spring 73 to a ball valve 72 controlling communication between a branch 71 of the conduit 27 and the conduit 69. Thus, in the neutral position of the shifter bars, the valve 72 is open and the valves 122, 22 closed ; pressure is supplied to the motor 8 by way of conduits 71, 69, valves 49, 66 and conduits 47, 45, 41, 38, 29, and the control valve 49 is thus effective to cause disengagement of the clutch 10. In the gear positions of the shifter bars, the valves 72, 122, 22 are all closed and pressure in the motor 8 is released by way of conduits 29, 38, 41. 45. 47 and the valves 49, 66. so that the clutch 10 is held open by its springs 13. The control valve 49, controlled by the governor 61 in accordance with engine speed, is similar to that described in Specification 520,596. It comprises connected intake and exhaust valves 55, 56, the valve 55 controlling communication between conduits 69, 65 and the valve 56 seating on a member 59 having a bore 57 leading to a chamber 53 connected to the atmosphere. The member 59 is carried by a diaphragm 60 subject through a choke 67 to the pressure of fluid in the chamber 52 and is movable axially against an adjustable spring 63 by the governor 61. At idling speeds, the seating member 59 engages the exhaust valve 56 and opens valve 55, allowing the pressure fluid to open the clutch 10. On increase of engine speed. the governor 61 assisted by the pressure on the diaphragm 60 moves the member 59 to the right, allowing the valve 55 to shut off the fluid supply. Further movement withdraws the member 59 from the exhaust valve 56 and the pressure in the servomotor falls, while reduction of pressure on the diaphragm 60 damps the exhaust valve to allow a gradual re-engagement of the clutch. The master valve 66, controlled from the accelerator pedal 80, is interposed between the conduits 65, 47 and comprises connected intake and exhaust valves 97, 102, the exhaust valve 102 being normally held by a spring 101 on a seat formed by a member 93 actuated through a bellcrank 91 from a collar 90 on the rod 82 between the pedal 80 and the engine throttle 87. In the idling position shown, the valve 97 opens a direct connection between the conduits 47, 69. When the accelerator pedal 80 is depressed, the bellcrank 91 is tilted by a spring 106 into engagement with a stop 108, allowing the valve 97 to close and exhaust valve 102 to admit pressure fluid through the outlet chamber 52 of the control valve 49, which then operates in dependence on engine speed. In a modification, Fig. 2, a valve system comprising a master valve 133 and a control valve 149 is controlled from the enginespeed governor 164. The master valve 133 is provided with connected intake and exhaust valves 145, 143, the latter normally seating on the end of a member 138 carried by a diaphragm 137 subject through a choke to the pressure in the chamber 140 and loaded by a spring 162. The member 138 carries a casing 148 provided with connected inlet and outlet valves 154, 155, the latter normally seating on a member 156 actuated by the governor 164 and lightly loaded by a spring 159. In operation, for example with the shifter bars 16, 18 in first gear position and the engine idling, increase of engine speed causes the governor 10 to move the member 156 to the right, closing the valve 154 and opening valve 155 ; fluid pressure from the servomotor then passes through conduits 132, 166, 139 to the outlet chamber 140, allowing exhaust to a pressure sufficient to maintain the clutch in light engagement. When the spring 159 has been taken up, further action of the governor effects movement of the casing 148 and member 138 to effect gradual engagement of the clutch with increasing speed.