Perpendicular alignment of vertical structures - is esp. for drilling derricks which require accurate positioning using optical plumb-line method

摘要

A method and device for the perpendicular location and orientation of vertical structures, in partic, of drilling derricks used in construction work, is designed for high accuracy of positioning above a defined point. A light source is fixed with freedom of movement to the construction and produces a sighting beam parallel to a vertical axis of the structure. The beam is directed towards the defined installation point. Observation of the alignment may be by use of a periscopic arrangement or a free-swinging television camera (210) in the base of the structure.