GB469911A - Improvements relating to adjusting means for the shoes of internally expanding brakes - Google Patents

Abstract

469,911. Adjusting brake shoes. PRATT, J. H., and MANLEY, G. E. Feb. 7, 1936, Nos. 3720 and 3721. [Class 103 (i)] An adjusting device for the shoes of internalexpanding brakes comprises a pair of thrust members to which the two shoes are respectively pivoted and each of which is screwed into one of a pair of sleeves adapted to be turned manually or automatically by a bevel pinion engaging teeth on the sleeves. In Figs. 3 and 4 which show a device adapted for both manual and automatic adjustment, a pair of thrust members 5 to which the ends of the shoes 19 are pivoted screw into sleeves 6 provided with teeth engaged by a bevel pinion 9a on a shaft 9c mounted, as are the members 5, 6 in a housing 7 secured to the back plate of the brake. A shaft 14 passes through the shaft 9c and is normally coupled to the shaft 9c by engagement of a conical part 14a on the shaft with the end of the pinion, this engagement being effected by a nut 15 on the shaft 14 abutting on the end 9e of shaft 9c. A member 17a rotatably mounted on the housing 7 is connected by a link 18 and spring 20 to one brake shoe 19 and to the shaft 14 by a one-way clutch comprising a coil spring 21 surrounding cylindrical parts 16, 14c on the member 17a and shaft. Release movement of the shoe thus turns the pinion 9a and effects axial displacement of the members 5 to adjust the shoes. Manual adjustment is effected by turning the shaft 9c by its squared end 9e after the shaft 14 has been uncoupled by slackening the nut 15. Undesired rotation of the parts and backlash is prevented by frictional engagement of the outer face of the pinion 9a with the housing effected by a spring 13 which abuts on the housing and on a cap 11 engaging a split ring 10 on the shaft 9c. In a modification for manual adjustment only, the shaft 14, member 17a and the operating means therefor are dispensed with.