DIAPHRAGM CLUTCH

In this type of diagram type springs are used instead of coil / helical springs. This type of clutch does not require any release levers as the spring itself acts as the series of levers. This type of springs do not have constant rate characteristics as in the case of coil springs and the pressure on the diaphragm springs increases until it is in flat position, thereafter decreases after passing this position. Hence the driver does not have to exert heavy pedal pressure to hold the clutch out of engagement compared to coil spring type. In coil spring type the spring pressure increases when the pedal is depressed to disengage the clutch and high pressure is required to keep the clutch in disengaged position.

This clutch consists of conventional friction clutch, thrust plate, diaphragm type spring and release sleeve. The diaphragm is held between the inner end of the main bearing and its outer circumstance fits into the counter bore of the thrust plate. The central position of the diaphragm spring is divided into several segments by radial slots terminating into holes. These segments acts like spring providing the required thrust on the pressure plate. This simple arrangement eliminates the necessity for providing separate release levers.

Working:  In the engaged position the spring pivots on the inner pivot rings as it is held on the clutch cover so that its outer rings contacts with the pressure plate. Again in this conical position the spring exerts through pressure to keep the pressure plate in firm contact with the clutch plate and flywheel. When the pedal is depressed the linkage moves release bearing toward the flywheel. When the pedal is depressed the linkage moves release bearing towards the flywheel to disengage the clutch. As the bearing contacts with inner position of the conical springs it moves that position forward which cause the link to move backward. This removes the pressure on the pressure plate and release the clutch plate from contact with other driving members.

Another type of conical spring used is the crown spring. This type differs from the tapered finger type with its surface corrugated instead of flat and the centre section is continuous without any spring. The clutch spring fits between the pressure plate and clutch cover. The entire assembly is held together by six spring retainer located on the pressure plate. The actuation of this type of spring is similar to integral / split type diaphragm spring