GB343197A - Improvement in brake construction - Google Patents

Abstract

343,197. Brake shoes acting on drums. EVANS, E. R., 1826, Diversey Parkway, Chicago, U.S.A. Nov. 26, 1929, No. 36183. Convention date, May 27. [Class 103 (i).] The operating cam 48 for a pair of pivoted brake shoes 16, 17 is fitted between wear members 39, 44 provided on the free ends of the shoes and having legs 42 extending on opposite sides of the cam provided with barrel-shaped portions 47, 50 adapted to engage the edges of the legs. The legs 42 are cut away on arcs of greater radii than the radii of the barrel-shaped portions 47, 50 of the cam which they engage and the lower legs are slightly spaced from the portion 50. An intermediate portion of the cam has shoulders 54 to support the cam normally on the wear members and to prevent wrong rotation. Cam portions 51 of the cam support and hold the cam on centre during operation. The part 43 of the wear members is slotted to receive the webs of the shoes and is secured by a single rivet 40. The brake shoe pivot member 14 is formed of hexagonal bar and fits in a hexagonal hole in a support member 12 riveted to the brake backing plate. The bottom of slots 15 in the member 14 are milled at an angle to the drum axis and the ends of the shoes received in the slots are formed upon similar angles so that rotation of a nut on the screened end of the member 14 adjusts the shoes to and from the drum. A spring- ball arranged in a transverse slot in the member 14 clicks against axial grooves in the thread on the interior of the nut to indicate the amount of adjustment. The webs of the shoes are cut away at 18 and the flange turned over to form rounded ends. An adjustable centralizing member 58 lies against the backing plate and has shoulders 61 bearing against the cylindrical flanges of the brake shoes. Securing bolts pass through slots 63, 65 arranged at an angle to one another in the member 58 and the backing plate respectively. A shoulder on each bolt is adapted to be passed through the slot 63 when assembling and engage the slot 65. A spring 74 is adapted to press the member 58 against the shoes when the bolts are slackened, and when the shoes have been forced against the drum by retracting the member 14, which is then adjusted to give the required clearance of the shoes. A device for preventing rattling comprises a spring 32 bent upon itself to engage both sides of the shoe web and held between a shoulder on a stud 30 and a cotter pin 34 passing through the stud. The stud is covered by the backing plate and passes through a slot in the shoe.