| 摘要 |
<p>The plumb-line unit consists of a plumb-line reel (5) which is connected to an automatic clockwork rewinder (6). The rewinder has a coil spring (21) whose ends are connected to a delivery spool (22) and a driving spool (20) of the plumb-line reel (5). This is housed in a casing (27) connected to the holder (2) which has a handle and a pointed end for inserting into the ground. A clamp (26) stops the reel (5) and the plumb-line (11) passes over guiding (12) and braking (28) pegs through a vertically adjustable guide (13, 14, 16, 17).</p> |
