Description & Operation
The primary function of the clutch is to couple and uncouple engine power to the transmission upon driver command. The clutch is a single plate, dry friction clutch disc. For an exploded view of the clutch, see Fig 1 . The clutch disc has a splined hub with integral torsional springs. The clutch disc hub attaches to the input shaft. Engine output is coupled to the transmission input shaft by friction existing between the clutch disc facings and the flywheel/pressure plate assembly.
The extent of this friction is directly related to the composition of the facing material and the magnitude of the clamping forces exerted by the pressure plate and the flywheel on the facings. These factors limit the amount of torque that can be transmitted without slippage. The clamping force is obtained from a diaphragm spring contained within the pressure plate assembly.
This force is developed during the attachment of the pressure plate assembly to the flywheel. The clutch system is disengaged when the clutch pedal is pressed and is accomplished when the release fingers are fully displaced toward the flywheel. This displacement removes the spring load from the pressure plate and eliminates the coupling friction between the engine and the transmission.
When the clutch pedal is depressed a cable connected to the clutch release lever, hub and bearing actuates the pressure plate diaphragm spring, releasing pressure on the clutch disc. This eliminates the engagement between the transmission and the engine.
The clutch control system engages and disengages the clutch. The clutch control system disengages the clutch when the clutch pedal is depressed and engages the clutch when the clutch pedal is released. Clutch pedal motion is transmitted by the clutch release cable to the clutch release lever. The clutch release hub and bearing engages the pressure plate diaphragm spring, releasing the pressure on the clutch disc which in turn disengages the transmission from the engine. The clutch adjusts automatically to compensate for clutch disc wear. The clutch linkage is self-adjusting.
The Clutch Pedal Position (CPP) switch prevents the starter motor from engaging unless the clutch pedal is depressed all the way to the floor. The switch plunger is contacted by the clutch pedal and extends as the clutch pedal is pressed. The clutch pedal position switch is electrically connected in line with the ignition switch and the starter motor relay coil. The CPP also turns off the speed control when the clutch pedal is depressed.