Improvements in or relating to electromagnetic multi-plate clutches

886,207. Friction clutches. INSTITUT FUR FORDERTECHNIK LEIPZIG. Aug. 6, 1959, No.26921/59. Addition to 798,367. Class 80 (2). The multi-disc friction clutch of the parent Specification, in which a driving shaft 8 is connected to a driven housing 10 upon energization of an electromagnet 1 attracting an armature 2, secured to a sleeve 4 drawn rightwards of the Figure to compress a dished spring 5, abutting at its outer periphery 15 against a pressure -plate 12, thereby biased to engage clutch discs 6, 7 for the transmission of torque, is modified by replacing the disengaging helical springs arranged in the sleeve by a ferromagnetic dished spring 17 engaging between the outer periphery 18 of the armature and the inner periphery of the electromagnet. The dished spring 17 serves to guide the flux from the solenoid to the armature, thus increasing the magnetic force on initiation of a clutch-engaging movement. In the form shown, the electromagnet 1 rotates with the driving-shaft 8, but in a modification, Fig. 2 (not shown), the electromagnet is stationary and is mounted by means of a ball-bearing upon the driving-shaft.