| 摘要 |
<p>PURPOSE:To make the unobstructed function of a brake possible even when a small stone or the like is caught in the brake by providing a shoe expanding part at the tip of a rotary sliding shaft to form an actuating lever, making the rotary sliding shaft slideable in the inside of a drum case, and snapably providing the actuating lever within the drum case. CONSTITUTION:An actuating lever B is formed as a shoe extending part 7 provided at the tip of a rotary sliding shaft 6, and the rotary sliding shaft 6 is formed so as to freely rotate and slide within the slid part 2 of a drum case A. The actuating lever B is provided so as to always be snapable within the drum case A. When a gravel or the like is caught between the drum case A and an actuating arm 9, the above formation makes the actuating lever B slide to a position where the actuating arm 9 gets over the gravel to protrude the rotary sliding shaft 6 from the inside of the drum case A to its outside. The rotary sliding shaft 6 rotates at the same time to expand the expanded parts 4b of brake shoes 4 through a shoe expanding part 7 for securing the functioning ability of the brake.</p> |
