| 摘要 |
A ratchet block, eg for use in yachting or dinghy sailing, comprises a block body 10 having a pair of side cheeks 11,12 and a sheave assembly 15 comprising a hub 16 supporting an annular sheave 17 for rotation about a principal axis. The sheave 17 has ratchet teeth 19 and a pawl 20 is mounted on the hub 16 or a side cheek 11,12 for movement between engaged and free settings. An actuator 25 is also mounted on the hub 16 or side cheek 11,12 and is linked to the pawl 20 to move the pawl 20 between its engaged and free settings. The hub 16 is pivotable between loaded and unloaded limiting positions about an axis, eg of a dowel 29, which is parallel to but spaced from the hub's principal axis. Spring means, eg three C-shaped springs 33, are provided for biasing the hub 16 to the unloaded limiting position. The actuator 25 and the hub 16 or said side cheeks 11,12 are interconnected, eg by a peg 38, such that pivoting movement of the hub under an applied load against the action of the springs 33 causes the actuator 25 to move the pawl 20 to engage the teeth 19. |
