| 摘要 |
In one aspect of the present invention, this is accomplished by providing a tower that includes a fixed member; at least one movable tower member, the at least one movable tower member is movable relative to the fixed member. The tower also includes a drive for moving the at least one movable tower member when power is supplied to the drive; and a tower position detection system comprising: a switch mounted on the fixed member and electrically connected to the drive, and an actuator member mounted in a predetermined position along the length of one of the at least one movable tower members so that when the one of the at least one movable tower members is in a predetermined location relative to the fixed member, the actuator is located proximate the switch to open the switch and terminate the supply of power to the drive.
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