DISC BRAKE PARTICULARLY FOR MOTOR VEHICLES

摘要

1494961 Spot-type disc brakes KNORR BREMSE GmbH 3 March 1975 [1 March 1974] 8688/75 Heading F2E A disc brake actuator device operable by fluid pressure and mechanically comprises a saddle 2 for brake linings 5, 6, a brake cylinder 7 secured to the saddle and adapted to receive fluid pressure medium at 44, a first piston 9 for driving engagement with brake lining 6, a second brake piston 24 exposed to fluid pressure in the opposite direction to that exerted on the first piston, the second piston being engageable, under fluid pressure action, with the cylinder 7 to apply a force thereto to move the saddle 2 for application of lining 5, and mechanical displacement apparatus 37 to 39 movable in a brake-actuating mode towards engagement with the second piston 24 for coupling with the first piston 9 to operate the actuator device mechanically, the engagement and coupling of the mechanical displacement apparatus with the pistons being such that in the event of operation of the device by both fluid pressure and mechanically, the mechanical apparatus is effective exclusively when the mechanical force on the second piston exceeds the opposing fluid pressure thereon, and vice versa. The lower piston and cylinder in the figure constitute an auxiliary fluid-pressure-only apparatus. As shown, the mechanical apparatus comprises a lever 39 integral with a tubular element 37 threaded into an extension 35 of the cylinder 7, and a normally-non-rotatable spindle 16 extends from piston 24 and has a reversible screw-thread connection with a nut 18 resiliently connected to piston 9 for wear-adjustment. After withdrawal of a screw 31 the spindle may be rotated to reset the adjuster by a screwdriver inserted in slot 28 of an extension 26. An axial clearance s between the threads of spindle 16 and nut 18 corresponds to the desired displacement stroke for maximum braking. In Fig. 2 (not shown), projection 26 of spindle 16 extends rightwards beyond the end of piston 24, hole 41 is smaller in diameter than the projection end, and the first turns of the mechanical apparatus act on spindle 16 (and thus on piston 9 directly) before piston 24 is engaged.