| 摘要 |
<p>A locking key, designed to retain an indication of the lock-shifting (opening or closing) operation last performed, has a head and a shank interconnected by a screw coupling with limited axial play enabling their relative rotation through 90 DEG or 180 DEG . The shank and its bit can thus be positively entrained for a lock-opening or a lock-closing motion only after the head has arrived in one or the other limiting angular position relative thereto. When the idle rotation of the head is 180 DEG , the relative angular position of the two parts can be indicated by special markings thereon.</p> |
