GB255599A - Improvements in braking devices - Google Patents

Abstract

255,599. Brown & Sons (Huddersfield), Ltd., D., and Merritt, H. E. June 2, 1925. Blocks and shoes acting on drums; actuated or applied by running axle or wheel. - The brake shoes of an internal expanding brake are arranged when applied to be carried around to a limited extent by the drum so as to cause the cam lever or other operating member to aout against a fixed stop or surface and thereby assist the operating effort. As shown in Figs. 1 and 3, a pair of shoes b and an operating cam f therefor are arranged in the usual way except that the pivots c, g for the shoes and cam respectively are mounted on a carrier d rotatably mounted on a fixed part e co. axiallv with the brake drum a. When the cam lever h is actuated to apply the shoes to the drum the shoes and other parts connected to the carrier d tend to rotate, with the drum so as to engage the lever h with one or other of the stops i and thus to increase the pressure applied to the shoes. Fig. 6 shows an arrangement of four shoes pivoted to the rotatable carrier d at b<2>, b<3>, a pair of cams f<1>, f<2> being disposed one between each pair of the shoes. The spindles g<1>, g<2> of the cams are also mounted on the carrier. When a lever such as h, Fig. 3, on the cam spindle g<2> is actuated the one pair of shoes b, b is applied and the consequent rotation of the shoes and the carrier d with the drum effects the engagement of an arm on the lever with a stop such as i, Fig. 3, and also the engagement of a lever on the cam spindle g', with a stop to apply the shoes ba. The stops may be in the form of inclined surfaces of variable inclination. The shoes may be expanded by levers, screws, or gearing instead of cams.