| 摘要 |
<p>A reversing drum brake comprises a pair of brake shoes 3, 4, the upper ends of which are connected by an expander 10. The lower opposing ends of the brake shoes 3, 4 are connected by a collapsing mechanism 13 within which there is disposed a slidable cylinder 18, a cam 27, and three steel rollers 24, 25, 26. During normal forward motion, the three rollers 24, 25, 26 are maintained in the position illustrated in Figure 1. During reversing, the three rollers 24, 25, 26 collapse and the cam 27 pivots anti-clockwise, to allow the overall collapsing mechanism 13 to collapse, and the brake shoes 3, 4 to move towards one another, thus overcoming braking effect.</p> |
