| 摘要 |
A measuring staff for use with a laser levelling or surveying system including a laser detector (30) for detecting a laser beam (29). The staff comprises a telescoping upper section having a first elongated member (12) and a second elongated member (13). The second elongated member (13) is extendable and retractable relative to said first elongated member (12) and the staff comprises a means for urging the second member (13) towards an extended position and opposing movement towards a retracted position relative to said first member (12). A means is provided for selectively locking said first member to said second member. The laser detector (30) is adapted to be located on and fixed to the first member (12) in a position aligned with the laser beam (29) in use to define a datum level. A graduated scale (18) on said first member (12) extends longitudinally either side of the datum level and an indicating means (17) movable with the second member (13) cooperates with said graduated scale (18) to provide measurements of levels above or below said datum level. A lower extension section (14) extendable from and selectively lockable to the upper section includes a second scale (24) for indicating the extension of the lower section (14) relative to the upper section.
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