GB857623A - Improvements in or relating to hydraulic drum brakes - Google Patents

Abstract

857,623. Hydraulic brakes. FRANCAISE DU FERODO S.A. Oct. 8, 1958 [Oct. 8, 1957], No. 32178/58. Class 103 (1). An hydraulically-operated shoe-drum brake of the kind which, as shown in Figs. 1a, and 1b, comprises a double feed, applied at chambers 13 and 14 respectively, but may have only a single-feed, with shoes which are subjected to a resilient restoring force in the position of rest and are adapted to bear frictionally against a rotary drum, when they are subjected to expansion is characterized in that the shoes co-operate with two coaxial movable pistons 21 and 23, which have positive abutment with respect to each other and resilient abutment means in relation to a fixed disc 10. These meanly define a minimum separation and a position of rest of the pistons and shoes, whereby in co-operation with at least one of the said pistons, there is ensured a certain appreciable reserve of oil. The resilient abutment means comprises on the one hand a sliding collar 30, which is adapted to abut against the cylinder, and against a piston, and, on the other hand, a prestressed spring 31 bearing at its opposite end against the piston 23.