| 摘要 |
1,253,566. Shoe drum brakes. NORTH AMERICAN ROCKWELL CORP. 23 April, 1969 [9 July, 1968], No. 20724/69. Heading F2E. In a wedge-type brake actuator in which a power-operated wedge assembly is displaced between adjacent ends of brake shoe-engaging plungers 30, 32, a force-transmitting assembly interposed between the wedge 22 and the plungers comprises a pair of anti-friction rollers 26, 28 which are cylindrical from end to end and adapted to be in rolling contact with the wedge and an adjacent plunger end, a carrier for the rollers comprising a mounting section 58 adapted to be supported on the wedge assembly and a pair of arms 54, 56 extending away from the mounting section and beinig adapted to extend along the sides of the wedge, and means on the arms for supporting and guiding the rollers and which contacts the rollers on the cylindrical surfaces thereof. As shown, a reciprocable wedge member 22 carries a cage 24 and rollers 26, 28 positioned between plungers 30, 32 reciprocable to operate brake shoes 42, 48, the plunger 34 being operated by the piston or diaphragm of an hydraulic or air actuator and being normally biased to a brake release position by a spring 36. The cage is formed from spring steel sheet and the rollers are engaged in openings in the arms 54, 56 and are confined between tabs 74, 76 and tabs 80, 82. In a modification, the arms 54, 56 are straight and there are inwardly and outwardly extending tabs 80, 82 at the upper and lower edges of the apertures in the arms. |
