| 摘要 |
<p>The level (1) has a circular end (13) provided with internal teeth (11). The teeth (11) can slide on the surface of a boss (2) which is keyed to the shaft (7), and which is provided with a flat surface (42). A toothed segment (4) is held against the flat surface (41) by a spring loop (3) which passes around a pin (6) attached to an end cover. When the lever arm (12) is moved in the direction of the arrow (A) the teeth (40) of the segment (4) slip out of engagement with the teeth (11). When the arm (12) is moved in the direction of the arrow (B) the teeth (40) of the segment (4) remain in engagement with the teeth (11) and cause the shaft (7) to rotate. By rotating the end cover the action of the mechanism can be reversed.</p> |
