555,158. Disc brakes. WIGGLESWORTH & CO., Ltd., F., and SUNDERLAND, A. Feb. 13, 1942, No. 1924. [Class 103 (i)] [Also in Group XXIV] Engagement and disengagement of a brake or clutch is made by means of a sleeve 7 screwed on the hub 4 of one of the clutch or brake members. An actuating sleeve 12 slidable on the sleeve 7 has one or more pins 11 with rollers 9, 10, engaging an axial slot 6 in the hub 4 and a curbed slot 8 in the sleeve 7 respectively. Between the sleeve 7 and the friction plates is a compound sleeve 15, 16 which is adjustable to take up wear. Portion 15 is keyed to the hub 4 and part 16 is screwed on the portion 15 and has a spring-pressed plunger 17 engaging one of a number of holes in the nearest friction plate. In operation the sleeve 12 is moved axially by a yoke controlled by an actuating lever and the rollers 9, 10 cause relative turning of the parts 4, 7 to engage or disengage the clutch, or brake. The curved portion 19, Fig. 3, of the slots 8 are shaped as shown to give greater purchase when the friction plates are nearing full engagement.