Principle of Operation
The ‘DS’ (Diaphragm Spring) type of clutch
illustrated opposite is bolted to the vehicle flywheel and is
made up of the various components as shown.
The pressed steel covers drives the pressure plate via the drive straps, with the diaphragm spring forcing the pressure plate towards the flywheel clamping the driven plate between them. Thus the engine flywheel, cover pressing, pressure plate and driven plate, all rotate together to transmit the drive to the gearbox via the splined shaft. Depressing the clutch pedal releases the driven plate by moving the release bearing in the direction of arrow ‘A’ to bring it into contact with the release plate. (The clutch may not be fitted with a release plate, in which case the release bearing will come into direct contact with the diaphragm fingers). This in turn applies pressure to the diaphragm spring fingers which move inwards and pivot on the fulcrum rings to lift up the spring outside edge. The retractor clips keep the spring in contact with the pressure plate which moves away from the flywheel (in the direction of arrow ‘B’) releasing the driven plate allowing the clutch and flywheel to rotate independently thus disconnecting the drive to the gearbox. Releasing the clutch pedal reverses the operation and the driven plate is once again clamped again against the flywheel to revolve the input shaft and apply drive to the gearbox. The ‘DST’ (Diaphragm Spring Tabbed) clutch works on the same principle as the ‘DS’ clutch except that the ‘DST’ clutch does not require retractor clips, and the diaphragm spring is located by tabs on the cover pressing rather than shouldered rivets.