The figure shows the design of a diaphragm spring clutch in the clutched and de-clutched conditions. The spring force brings the clutch disk into adherent contact with the flywheel over the pressure disk. The clutch disk transfers the engine torque into the transmission. In the declutched condition, the pressure disk is withdrawn from the clutch disk. The torque transmission from engine to transmission is disconnected.
In case of a rigid design of the operating mechanism, a torque peak would result during clutch engagement. In order to prevent this, nearly all clutch disks today are equipped with a lining springs. Furthermore the axial springs between the clutch linings lead to a uniform load transfer and thus to a lower lining wear.