| 摘要 |
1506852 Actuators for internal shoe-drum brakes; wear adjusting GIRLING Ltd 6 June 1975 [13 June 1974] 26212/74 Heading F2E An actuator for an internal shoe drum brake comprises axially aligned tappets 1, 2 for engagement with respective brake shoes which tappets 1, 2 are slidably guided in a housing 4 and are arranged to be urged apart to apply the brake by the forcing of a wedge member 14 with the interposition of rollers 18, 19 retained in a cage 20 between the inner end faces 11, 13 of the tappets 1, 2, the inner end face 11 of tappet 1 being normal to the axis of tappet 1, and the line of action of the wedge member 14 being inclined to the plane of face 11. In the illustrated embodiment, the inner end face 13 is constituted by the base of a transverse slot 12, and the line of action of wedge member 14 bisects the angle between the inner end faces 11, 13 so that movement of the wedge member 14 urges the tappets 1, 2 in opposite directions by equal amounts. The tappet 1 is formed in two parts 8, 9 threadedly engaged, the part 9 having gear teeth engageable by a meshing gear for effecting rotation of the part 9 to adjust the length of tappet 1. The housing 4 is adapted to be secured by a flange 5 to the backplate with the plane face 5<SP>1</SP> in engagement therewith and the line of action of the wedge member 14 may or may not be inclined to a plane B normal to the face 5<SP>1</SP> and parallel to the brake axis. The wedge member 14 is carried by an integral actuating rod 15 and the cage 20 has an enlarged head 21 which is a loose fit on the rod and prevents the rollers 18, 19 from passing into a space 22 in the housing 4. |
