Control for an adjustable boom extension of a mobile crane

摘要

The controller has a jib extension placed on a telescoping main jib (2). A luffing angle of the jib extension is adjustable by a luffing winch or a piston-cylinder unit. The actuation of the winch moving a luffer (1) or the piston-cylinder unit is carried out via a control circuit such that an angle (30) of the luffer with respect to the telescoping main jib and/or an horizontal remains constant or changes to a predefined extent during extension and/or retraction of the telescoping jib, or when changing the angle of the main jib with respect to the horizontal.