Patent GB-859612-A (GB)
Title: Improved clutch control system for motor vehicles
IPC: F16H63/46
Filed: 1958-08-05
Abstract: 859,612. Gearing for stopping and starting machinery. TATRA NARODNI PODNIK. Aug. 5, 1958 [Aug. 20, 1957], No. 25061/58. Class 80 (2). The main clutch of a motor car, driving to a conventional synchro-mesh change-speed gear, is disengaged during ratio shifts by closing a ratio-shift-lever mounted switch 25 to energize a solenoid 10 opening a valve 8 so that a pipe 46, leading from a vacuum tank 3 connected through a non-return valve 2 and a pipe 1 to the inlet manifold of the car engine, communicates with a pipe 51 in turn communicating, through a valve 17 held open by an enginedriven speed governor 18 at engine speeds greater than 800 r.p.m., with a pipe 52 and a throttle-pedal adjusted valve 21 leading through a pipe 48 to a servomotor 5 controlling the main clutch. Establishment of a ratio in the changespeed gear slides a selector rod 31 from the neutral position shown, a groove 43 therein acting through a strut 32 to close a switch 33 energizing a solenoid 14 to condition a valve 12 so that a pipe 47, also leading from the vacuum tank 3, communicates with a pipe 50 which, at engine speeds below 800 r.p.m., communicates through the engine-speed governor-controlled valve 17 and the pipe 52 with the servomotor 5 to maintain clutch disengagement. At engine speeds below 800 r.p.m., if the ratio-shift lever is moved to its neutral position, the selector rod 31 opens the switch 33, the solenoid 14 is de-energized, and the valve 12 opens to atmosphere to de-energize the servomotor 5 and reengage the main clutch. The valve 21, controlled. by the car throttle pedal 24, gives restricted communication between the pipes 52, 48, the restriction being greatest when the pedal is slightly depressed. The selector rod controlled valve 12 is also alternatively controlled by a switch 34 mounted upon the car dashboard. Initial movement of the car is obtained by first starting the engine with the gear in neutral so that the valve 12 connects the servomotor 5 to atmosphere and the main clutch is engaged. By closing the ratio - shift - lever mounted switch 25, the valve 8 is opened, but at engine idling speeds, the speed governor 18 conditions the valve 17 to stop communication between the pipes 51, 52, and no effect is obtained thereby. On moving the ratio-shift lever to establish a ratio in the change-speed gear, the selector rod 31 slides and closes the switch 33, which energizes the solenoid 14 and conditions the valve 12 to connect the vacuum tank 3 &c. through the pipes 47, 50 to the valve 17 and thence via the throttle-pedal controlled valve 21 to the servomotor 5, which disengages the main clutch. On depression of the accelerator pedal 24, the engine speed increases and the governor 18 conditions the valve 17 so that the pipe 52 no longer communicates with the pipe 50, but instead communicates with the pipe 51 which, when the ratio-shift-lever mounted switch 25 is open, communicates through the valve 8 with the atmosphere. Accordingly, atmospheric pressure is admitted through the pipe 52, the throttle-pedal controlled valve 21 and the pipe 48 to the servomotor 5, and the clutch engages.