US Patent 7798302 Electromagnetic clutch

In this electromagnetic clutch, a compressive force is generated in a plate spring when an armature plate is contact with a first rotor. Therefore, a force in the direction away from the first rotor acts on a first bent portion of a plate spring. However, an extension portion of a second rotor is capable of abutting to the first bent portion from the direction opposite to the first rotor. So a stress generated in the first bent portion is dispersed to the extension portion.