| 摘要 |
In a fastener, an elongate body (10) is formed with a plain bore (11) in which there is mounted a threaded spindle (12) which threadedly engages a tapped, extended portion (24) of a nut (14). The lower end of the spindle (12) affords an actuating portion (16) which slides in an enlarged bore (17). Balls (19) are captive in the body (10), and each seats in a shallow cup (21) in the actuating portion (16), adjacent to and overlapping a deep cup (22). The nut (14) is tightened to clamp against the upper surface of a component (2) to be fastened to a table (5), and the balls are tightened against the chamfer (7) of holes in the table (5). The engagement of the balls (19) in the cups (21) prevents a spindle (12) from turning. Since the contact surfaces of the balls (19) and cups (21) are substantially part-spherical, and preferably substantially equal, a relatively good contact area can be provided, and thereby damage of the actuating portion (16) due to indentation by the balls (19) under high clamping loads can be largely avoided. In order to release the fastener, the nut (14) is rotated to loosen the clamping. Since the spindle (12) cannot rotate, due to engagement of the balls (19) in the cups (21), it is moved axially downwardly, until the balls (19) can retract into the deeper cups (22). When the balls are fully retracted, they no longer abut the chamfer (7), and the fastener (1) can easily be removed. Other fasteners, clamps and baseplates are also disclosed, advantageously for use in modular fixturing, especially in welding applications. |
