| 摘要 |
A strut (10) extending between a pair of brake shoes (2, 3) is constrained to move outwards together with one brake shoe (3). Arranged eccentrically and pivotably on the other brake shoe (2) is a rotatable cam (17) and this is in non-rotatable engagement with the strut (10). When the brake shoes (2, 3) are separated beyond a predetermined amount, the cam (17) is released from the strut (10) and rotated by a torsion spring (20) into a position in which it is brought back into engagement with the strut (10) and a new, retracted position of the brake shoes (2, 3) is set. <IMAGE> |
