Patent GB-1097817-A (GB)
Title: Friction clutch operating system
IPC: F16D48/06
Filed: 1966-08-24
Abstract: 1,097,817. Clutch control. FORD MOTOR CO. Ltd. Aug. 24, 1966 [Oct. 15, 1965], No. 37884/66. Headings F2D and F2L. A spring-engaged friction clutch is disengaged by a suction servo 68, a chamber 70 of which is connected to engine induction manifold vacuum at low engine speeds and which, at high engine speeds, is selectively connectible to atmosphere or to a vacuum reservoir to engage and disengage the clutch under the control of a steering-column mounted gear-shift mechanism. To cushion clutch engagement when low or reverse gear is engaged a servo chamber 74 has restricted communication to the atmosphere, the restriction being removed in intermediate and high gears. The clutch is engaged by springs 50 and is disengaged by the servo acting on a fork 52 engaging the usual release bearing which acts through release levers 32. The levers 32 have heavy ends 46 tending to engage the clutch by centrifugal force. In order to disengage the clutch to permit starting of the engine the fork 52 can be operated by a hand pull-out cable 60. The working chamber 70 of the servo 68 is connected by a line 100 to an engine lubricant pressure controlled valve 104 which at low engine speeds connects line 100 to a line 134 leading to the inlet manifold so that engine suction disengages the clutch. When the engine speed is increased above idling, valve 104 is actuated and connects line 100 to a line 118 which is connected to atmosphere or to the vacuum reservoir under the control of gear-shift mechanism actuated valves. A valve block 184 is carried by a rotatable and axially slidable tube 150 actuating shift levers 142, 146, the tube 150 being connected by a spring 175 to a tube 160 to be rotated thereby. The tube 160 is rotated and shifted axially by a manually-operated gear lever, and carries a fork 162 co-operating with a valve 212 controlling connection of the vacuum reservoir to the line 118 and also cooperating with a valve 236 controlling connection of line 118 to the atmosphere. Rotation of the shift tube 160 to change gear causes relative rotation between the tubes 150, 160, due to the resistance to movement of the shift levers 142, 146, and the fork 162 first engages valve 236 to close the connection between line 118 and the atmosphere and then unseats valve 212 to open line 118 to the vacuum reservoir to disengage the clutch. The clutch is reengaged when the tubes 160, 150 return to their initial relative position on the completion of shift and the removal of pressure from the gear lever. In the upper position of the tubes 160, 150, corresponding to intermediate and high ratios, a cushion valve 188 is aligned with abutments carried by a fixed tube 138, rotation of the tube 150 causing the abutments to unseat the cushion valve 188 to give rapid clutch re-engagement. When tube 160 is shifted downwardly to its low and reverse position, the tube shifts relatively to the tube 150 until an end of a slot in the tube 160 abuts a stud 178 by which the valve housing 184 is secured to the tube 150, whereafter the tube 150 shifts axially with the tube 160. The relative movement between the tubes shifts the cushion valve 188 out of alignment with the fixed abutments so that on re-engagement the servo chamber 74 is exhausted through a restricted orifice 202 in the cushion valve to cushion engagement.