GB406517A - Improvements in or relating to brake mechanism - Google Patents

Abstract

406,517. Brakes. NAPIER & SON, Ltd., D., 211, Acton Vale, Acton, and SEWELL, C.W., 2, Holly Park Road, Finchley, both in London. May 15, 1933, No. 14109. [Class 103 (i).] Means for equalizing the clearance of two brake shoes from a brake drum comprises a member which acts upon the shoes and is slidable transversely with frictional restraint upon a rotatable operating spindle. This device may be combined with means for adjusting the clearance of the shoes as described in Specification 406,518 and it may form part of mechanical means for applying a brake which can also be applied by a hydraulic cylinder. Brake shoes B can be applied by a hydraulic cylinder B<3> and also by mechanical means which includes the means for equalizing the clearance of the two shoes from the drum A and also for reducing the clearance of both shoes to a predetermined amount. A cam C engaging projections B<4>, B<5>, on the shoes B can slide with frictional restraint on the flat end D of the operating spindle Dx, which is mounted in the fixed bearing E. The frictional restraint is provided by disposing the cam C between a flange D<1> formed on the spindle and a spring washer D<3> threaded on it. The arm F of the spindle D<x> is connected by links H<2>, to a bell-crank G<2> mounted concentrically at G<1> with a hand-lever G operatively connected to the bell-crank by a screwed rod J<1>. A winged handle J<4> pivoted at J<3> to the rod J<1> has a cam surface J<6> for engagement with the lever G. The rod J<1> is normally locked against rotation by the engagement of its non-circular head J<2> with a corresponding recess in the lever G. A locking pawl and rack G<5>, G<6> is provided for the lever G. The brake shoes B may thus be applied by the lever G through the cam C and if one shoe is applied before the other, the cam slides on the spindle D against the frictional restraint so that when the shoes are released the clearance is equalized. To reduce the clearance of both shoes, the handle J<4> is turned on the pivot J<3> to a vertical position and by the action of the cam surface J<6> the rod J<1> is lifted and the shoes are thus moved towards the drum. The rod J<1> can then be rotated until the shoes are actually applied. Upon returning the handle J<4> to the position shown, the shoes are spaced from the drum to a predetermined extent. If the hydraulic operation only of the brakes is desired the adjusting means J<1>, J<4> may be mounted upon the anchor plate of the brake.