GB599541A - Improvements in or relating to brakes for vehicles - Google Patents

Abstract

599,541. Disc brakes. ROBERTS, G. P. Oct. 27,.1945, No. 28459. [Class 103 (i)] A disc brake comprises a pair of friction rings arranged to be given a part rotation in opposite directions to cause them to be moved apart by balls in conical recesses or other means, to engage annular friction surfaces secured to the 'member to be braked. Certain of the conically recessed members may be adjustable automatically or manually to take up wear of the friction surfaces. A pair of channel-section rings 10, 11 are rotatably mounted on a cylindrical member 14 secured to the axle assembly of a vehicle wheel and carry friction linings 15 for engagement with a two-part casing 29, 30 which may be bolted to the wheel or may be extended radially to receive a detachable wheel rim. The rings 10, 11 are urged towards each other by wire springs and carry conically-recessed members 17, 18 that receive balls 16. The rings can be turned in opposite directions to cause the balls to move them apart by tappets 21, 22 that engage abutments 25, 26 on the respective rings and are moved by a wedge 23 and interposed balls 31. The stem 32 of the wedge has a ball-andsocket attachment 33 to a plunger 34 slidable in a socket 35 on the back-plate 36 and actuated by a cable 37 or a rod 40. The tappets are urged towards each other by a spring 24. When the rings 10, 11 contact the rotating casing the frictional torque causes one or other ring, according to the direction of rotation, to engage a stop and the other ring to turn further, thus giving a self-energising action. The plunger and socket 34, 35 may be replaced by a similarly arranged hydraulic cylinder, the piston acting however to push the wedge or a radially arranged lever pivoted at its middle point on the back plate may be connected at its ends to the stem of the wedge and a pull-rod. The wedge may be operable both hydraulically by a pedal-operated master cylinder and mechanically by a hand lever or a wedge and tappets 21, 22 may be arranged at diametrically opposite positions on the brake the wedges being respectively operated hydraulically by a pedal and mechanically by a hand lever. To take up wear of the friction surfaces one of the rotating surfaces may be adjustable manually towards the other by screw means or as shown the members 18 may screw into sleeves 19 on the ring 11 and be toothed to mesh with a toothed ring 51 which may be turned manually as by rotating one of the members 18 or automatically by a pawl 53 pivoted on one of the rings 10, 11 and abutting on a stop 54 on the other ring. The pawl engages ratchet teeth 52 on the ring 51 and if in an application of the brake the relative rotation of the rings 10, 11 is excessive, the pawl slips a ratchet tooth and the ring 51 is advanced during the return movement of the rings 10, 11. The normal position of the pawl is determined by a stop 56.