Semi-centrifugal clutch. Sometimes single-plate clutches are designed as semi-centrifugal clutches. This clutch differs from the single-plate clutch, that the pressure of the pressure plate and the clutch plate against the flywheel is exerted not only by the pressure springs, but also by the centrifugal force of the weights mounted on the extension of the switch-off levers. The force of the compression springs can therefore be reduced, which reduces the driver's effort when disengaging the clutch.
The principle of the weights is as follows: Brackets are bolted to the clutch cover, with rotary disengaging levers mounted on the axles. The levers are also rotatably mounted in needle bearings, in the lugs that are one piece with the pressure plate. As the rotational speed of the engine crankshaft increases, weights, due to centrifugal force, they exert pressure (with compression springs) on the pressure plate, then onto the clutch plate, pressing it against the flywheel with additional force. Semi-centrifugal clutches are used in FSO Warszawa cars, Star i in. Centrifugal clutch. In this clutch, the clutch disc is pressed against the flywheel by a pressure plate under the influence of the centrifugal force of weights located on the circumference of the clutch. This force overcomes the resistance of the springs at high engine speeds, causing the pressure plate to move towards the clutch plate.
The clutch is disengaged automatically, when the rotational speed of the engine's crankshaft decreases. Then the centrifugal force of the weights becomes less than the force of the springs, under the influence of which the pressure plate is retracted.