| 摘要 |
<p>This lever of the first class with accessories for releasing and allowing quick movement of each leg (5A, 5B) of a bow compass has an intermediate bearing fulcrum (3) which is kept in contact with the surface of the leg (5A, 5B) by the thrust of a reaction spring (11) and is assisted in this by the cooperation of two transversely-retaining side plates (4A, 4B) engaged against their respective leg (5A, 5B) and comprising auxiliary inward fixing projections (4C, 4D) at their rear end. Said reaction spring (11) directly acts on a bush (12) carrying a half lead nut (16), so reducing the amount by which the operating end (1) of the lever (L) projects beyond the plane of the leg (5A, 5B) on which it is mounted. The bush (12) performs a fixing function by its insertion though a hole (6) provided at the reaction end (2) of the lever (L) followed by its rotation through 90 DEG to cause undercut elements of the head (9) provided on the bush (12) to engage with said reaction end (2) of the lever.</p> |
