摘要 |
A nut and bolt arrangement in which the nut is in two portions (10, 12) both of which have a threaded interior passage (14) of the same diameter for receiving a common bolt (18). The portion (10) has an annular formation (20) which has a greater diameter but smaller thread pitch than that of the passage (14). Portion (12) has at the same diameter, a matching external thread (13). When locked onto a bolt, this arrangement cannot be loosened without a special tool for engaging at (22). |