Clutch is a device used for interrupting power transmission, commonly between engine and gearbox in a car or an automobile.
In considering a single-plate friction clutch, there are two driving members which are the flywheel of the engine and the pressure plate. Sandwiched between these two driving members is the driven plate which is attached by splines to the driven shaft. Coil springs press the pressure plate against the driven plate and so into contact with the flywheel face. To disengage the clutch the pressure plate is levered away from the driven plate against the pressure of the coil springs.
On the other hand, when referring to the multiple-plate clutch, three plates having friction inserts are sandwiched between four plain plates. In the clutch-engaged position the spring pressure plate forces the plain plates tightly against the friction plates so that the power transmitted by the sprocket is transferred via the clutch case to the clutch hub which causes the mainshaft to revolve. Pressure on the clutch lever causes the clutch rod to move to the left (as shown) and release the spring plate pressure; this enables the clutch sprocket to revolve on its bearings without rotating the clutch hub.