Patent ID: 8024895

Claim:
An arrangement for the raising and lowering of a mast, which comprises: an upper mast portion and a base, which upper mast portion is rotatable about a horizontal pivot axis, located in the base of the mast, which arrangement comprises: (i) a docking latch for restraining the upper mast portion against rotation; (ii) mounting brackets for attaching lift rams for driving the docking latch between a first engaged configuration wherein the upper mast portion is restrained against rotation and a second disengaged configuration wherein the upper mast portion is free to rotate and (iii) a lock selectable via an intermediate unlocked configuration, in which a cam plate thereof is disengaged with a figure of eight shaped aperture, between a first locked configuration wherein the docking latch is engaged and said cam plate is engaged in an upper part of said figure of eight shaped aperture, and a second unlocked configuration wherein the docking latch is disengaged and said cam plate is engaged in an lower part of said figure of eight shaped aperture, (iv) characterized in that one or more sensors for sensing the vertical alignment of the upper mast portion and/or the configuration of the lock, and/or the configuration of the docking latch and/or the proximity of the upper mast portion to the ground is also provided; and the lock is controllable remotely to allow automatic operation of the raising and lowering sequence.