Patent GB-602772-A (GB)
Title: Clutch control mechanism
IPC: B60K23/02
Filed: 1945-11-07
Abstract: 602,772. Controlling clutches and changespeed gearing. BENDIX AVIATION CORPORATION. Nov. 7, 1945, No. 29640. Convention date, Dec. 13, 1944. [Class 80 (ii)] [Also in Group XXIX] A clutch control mechanism for motor vehicle transmissions of the type in which the accelerator is released to effect clutch disengagement on changing gear comprises a control valve including a valve member adapted to be actuated by a lever operatively connected, on the one hand, to a spring and pressure differential operated motor and, on the other hand, to an accelerator operated member. As shown, applied to the control of an engine-suction servo-motor 10, Fig. 1, operating a vehicle main clutch arm 16 independently of the clutch pedal 20, a slidable valve member 30, Fig. 3, mounted in a valve body 26 and controlling the admission of vacuum to both the motor 10 and a spring- loaded follow-up motor 59, has pivoted thereto a floating lever 32 whose ends are engaged .respectively by a rod 46 rigid with the diaphragm 50 of the motor 59 and by an accelerator operated plunger 76. Both the motors 10, 59 communicate with a chamber 24 via conduits 22, 92 respectively and therefore, when the valve member 30 is in the position shown, through passages 42 with a duct 34 which leads to a chamber 40, Fig. 4, able, when an overriding solenoid valve 102 is actuated, to communicate through a non-return valve 116 with a pipe 110 connected to the engine inlet manifold 112. Movement of the valve member 30 to the left first cuts off the supply of vacuum to the chamber 24 by lapping the passages 42 and then vents the chamber via the valve bore 210 and the hollow interior of the member 30 to a chamber 70 which is always connected to atmosphere through a bore 72, pipe 74 and air cleaner 75. The solenoid valve 102 is controlled by three grounded battery switches 152 and 148, 150, Fig. 1, operated by a vehicle speed responsive governor (not shown) mounted in the vehicle three-speed and reverse gear box 180 and by a column gear shifter 154 respectively. These switches are connected mutually in parallel and complete the circuit of a battery 202, an ignition key 200, a manual cut-out switch 198 and the solenoid 98, when the vehicle is at rest or running below a certain speed or when a gear change is initiated. The gear shifter 154 is connected through a downwardly spring- urged rod 160 to a crank 170 carrying a rod 172 which normally engages a slot in a lever 176 to rotate the latter but can be drawn upwards by the shifter 154 to engage instead a similar slot in a lever 184. The levers 176, 184 are linked to the low-reverse and high-second speed shifter levers 158, 156 respectively of the gear box 180. The switch 148 is linked to the lever 184 to close on initial high-second gear changing rotation of the shifter 154 in either direction, and the switch 150 is closed when its operating plunger passes from a reduced portion 190 of the rod 168 on to the full section of the rod when the latter is drawn upwards prior to engaging low or reverse gear. With the accelerator released the plunger 76 and valve member 30 are in the position shown in Fig. 3, the motors 10, 59 being powered and the clutch disengaged if the solenoid 98 is also energized. The plunger 76, accelerator pedal 118 and throttle valve 120 are interconnected by a lost-motion linkage comprising a bellcrank 124 on a fixed pivot 126, one arm of which is linked to the throttle and the other arm of which has pivoted thereon a lever 90, connected by rods 88, 128 to the plunger 76 and accelerator pedal 118 respectively. The lever 90 abuts against an adjustable stop 206 on the crank 124 to initiate throttle opening only when the pedal 118 has been partly depressed to cause the lever to pivot about the crank giving a relatively large movement to the plunger 76 and moving the valve member 30 to the left to vent the motor 10 and cause the clutch plates to approach each other rapidly. The spring loading of the follow-up motor 59 is so adjusted by a screw 64 that when the clutch plates are about to meet the rod 46 is moved to the right far enough to lap the valve member 30 and prevent actual engagement. Further step-by-step or continuous depression of the pedal 118 now rotates the linkage 90, 124 solidly about the pivot 126 and opens the throttle, the plunger 76 being correspondingly moved relatively slowly to the left and, through the lever 32 and the follow-up motor 59, controlling the member 30 to ease the clutch into engagement. To ensure smooth clutch engagement when the pedal 118 is rapidly depressed a bleed passage 86 is provided with which an annular cut-away 80 on the plunger 76 registers when a collar 78 abuts the valve body on full depression of the pedal 118, such registration causing more rapid venting of the motor 59 and moving the member 30 far enough to the right to reconnect the motors 10, 59 to vacuum. The invention may be used with a two-speed and reversing gearing, changes between the forward speeds of which are controlled jointly by the accelerator and a vehicle speed responsive governor with momentary engine ignition disablement on downshift, a fluid coupling being optionally provided in the transmission.