GB1057030A - Improvements in disc brakes - Google Patents

Abstract

1,057,030. Disc brakes. GIRLING Ltd. Nov. 29, 1963 [Dec. 4, 1962], No. 45741/62. Heading F2E. In a disc brake of the kind in which friction pads 23, 27 adapted to be urged into engagement with opposite faces of a rotatable disc 14 are mounted in a caliper which is angularly movable about an axis 22 substantially at right angles to the axis of the disc, one friction pad (27) being applied to the disc by actuating means located in the caliper on one sideof the disc and the other friction pad (23) being applied to the opposite face of the disc by the reaction of the caliper, the latter comprising a pair of spaced parallelsideplates 15 (not shown), 16 rigidly connected by an intermediate member 17 which straddles a portion of the periphery of the disc, and the caliper being pivoted by means of the side plates on a stationary member adjacent to the disc. The pivot comprises a cylindrical barrel 21 which is rigidly mounted on a stationary lug 18 secured to an axle casing 19 and the caliper pivots on a pin 22 which passes through the barrel 21. The directly actuated friction pad 27 may be actuated by a piston 33 working in an hydraulic cylinder 34 mounted between the side plates and also by a mechanical actuator 37 (Fig. 4, not shown) which may be combined with or incorporated in hydraulic actuator. A plunger 29, adjustably screwed into a sleeve 31, extends at one end through a clearance hole 32 in the inboard end of the member 17, the outer end of the sleeve 31 is guided in and is engaged by the piston 33 working in the hydraulic cylinder 34. The brake may be applied by means of a hand brake lever, coupled to a cable (not shown) and the cable is connected to an arm (not shown) extending tangentially from a ring 39 which is angularly movable about the sleeve 31 such that balls 41, located in inclined recesses, move the ring 39 in an axial direction also and, through a thrust bearing 43 bearing on a flange 44 at the forward end of the sleeve, the sleeve and plunger are advanced to apply the brake. Automatic brake adjusting means is provided in the form of a toothed wheel mounted on the inner end of the plunger 29 which co-operates with a pawl so that when the angularly movementof the ring 39 exceeds a predetermined value the ring moves the sleeve 31 angularly through a slipping clutch to advance the plunger relative to the sleeve. The part of Fig. 3 above the axis of the hydraulic cylinder shows the plunger 29 in the position relative to the sleeve in which it is when the pads are new, while the part below the line shows the plunger in the position corresponding to the pads when in a worn state and ready for replacement. The mechanical actuating mechanism and the forward end of the plunger 29 are enclosed by a rubber boot 46 to prevent entry of water or dirt and the end of the boot adjacent the brake disc is provided with an apertured sheet metal plate 47 which closes the opening in the member 17 and forms a resiliently mounted guide for the plunger 29. The non-actuated pad 23 is retained in position by a spring member 48, the ends of which engage the backing plate of the pad and which is engaged under hooks 49 on the side plates 15, 16.