| 摘要 |
1. A drum brake comprising two lined shoes (12, 112-14) which can be urged into frictional engagement with a rotary drum by brake applying means (28) situated between two first ends (30, 130-32) of the shoes (12, 112-14), a fixed fulcrum block (34, 134) situated between the other two ends (36, 38) of the shoes (12, 112-14), a spacer (44, 144) mounted in the vicinity of the brake applying means (28) between an adjusting lever (60, 160) pivoted on a first one of the shoes (12, 112), and the second shoe (14), and extensible member (64, 164) situated between the free end of the adjusting lever (60, 160) and the first shoe (12, 112), said member (64, 164) comprising a first element (66, 166) prevented from rotating and a second element (70, 170) rotation of which causes the member (64, 164) to extend, adjusting means being provided to rotate the second element (70, 170) through a one-way coupling (72-80, 172, 180) when the wear on the linings (24, 26) of the shoes (12, 112-14) exceeds a predetermined value, characterized in that the adjusting means comprise a link (78, 178) capable of moving in a direction substantially perpendicular to the axis of the extensible member (64, 164) under the influence of a counter link (76, 176) kept in permanent contact with the spacer (44, 144) by resilient means (86, 186), so as to rotate the second element (70, 170) of the extensible member (64, 164) by way of said one-way coupling (72-80, 172-180).
|
