Hinged windmill mast which may be raised or lowered - uses jack which is telescopic pivoted at ground level and attached to ring at foot

摘要

The windmill mast can be lowered to allow maintenance etc. of the blades and equipment carried at its head. The mast (1) consists of two folded sets of sheeting welded together to provide a polygonal cross-section. The mast foot is normally bolted (12a) through a base-plate (10) to plates (12) buried in the ground and has a hinge (14) at one side. The mast is lowered and raised with the bolts removed by a telescopic jack (17a) pivoted (22) at ground level and attached to a ring (15) a short distance up from the mast foot. The lower end of the jack is recessed into a chamber (20) in the ground, its pivot points being held by large masonry blocks resting on a reinforced concrete base.