GB199796A - Improvements in friction clutches and brakes - Google Patents

Abstract

199,796. Lancashire Dynamo & Motor Co., Ltd., and Whitmore, H. B. March 28, 1922. Clutches, friction of the type in which adjustably-weighted segmental shoes driven from their trailing ends by projections of the driving-element are adapted to expand centrifugally into engagement with the cylindrical inner surface of the driven or stationary element. The driving- projections, in the form of pins or lugs, are furnished with leather or other flexible and renewable thrust-transmitting pads or washers. The driving-projections are preferably arranged between the shoes, so that drive may be in either direction, and the ends of the shoes may be so shaped that the thrust thereon augments, opposes, or has no effect on the engaging-force. In the clutch shown in Figs. 1 and 2, a drum B, forming with an integral or attached extension B<1> a belt pulley, runs freely on a bush A keyed to the end of a driving-shaft (not shown). The bush A has a flange a<1> carrying pins a<3>, on which are threaded a number of approximately rectangular leather washers D held in place by nuts a<5> and a ring E. The washers D contact with the end faces c<1> of shoes C, which are provided with adjustable weights c<3> threaded on screwed stems c<4>, and have riveted to them woven asbestos fabric or other 'friction facings c<2>. A plate F encloses the clutch parts, and through this plate passes the stem of a grease lubricator g<1>. The lubricator is screwed into a plate G, which is secured to the bush A and encloses a cavity between itself and the shaft end. Grease passes from this cavity by grooves in the shaft or bush to an annular chamber a<6>, and thence by passages a' to the boss b<1> of the pulley. In a modification, Figs. 6 and 7, the driving-member has radial arms a<9> having projecting lugs a<8>, to which are riveted U-shaped leather pads D<1>. The cover plate, ring E, and lubricator g<1> are disposed as shown in Figs. 1 and 2. The shoes C may be castings or, as shown, may be bent up from bar metal; their ends c<1> may be parallel or inwardly convergent or divergent, and the lugs a<8> may be conformably shaped; a ridge may be formed across each face c<1> in order to localize the driving-thrust. In a further modification of the construction shown in Figs. 6 and 7, the pads D<1> are replaced by discs, each held in a recess in the faces of the lugs a<8>, and built up of cylindrical washers or of a spirally-wound leather strip. In any of the forms, the driven element may be keyed to an aligned shaft, and is then in the form of a drum overhanging the driving-shaft and provided with a cover plate apertured to run on the driving-bush A. Where springs are used to prevent engagement below a predetermined speed, they may take the form of blade springs H, Fig. 20, acting on the stems c' and bearing under lugs a<8>. In modifications, the stems are similarly connected to a deformable spring ring or to helical tension springs.