Abstract: An adjustable personnel platform (38) is rotatably fastened on a lift tower end, with a carrying arm (42) and a pivot link (43) in the pivot plane of the elements (15, 21, 26) of the lift tower. It is automatically held horizontal through a reversable electric motor (96) and a speed translating drive (66, 67) as well as through a control surrounding a regulator with an inclination measuring device (92). The speed translating gear drive (66, 67) directly drives the rotatable part (64) of the pivot link (43). Between carrying arm (42) and the motor a plurality of direction changing couplings (81, 86) are provided. They arrest the rotation of the carrying arm (42) in both directions of rotation and release the rotary direction of the carrying arm (42) in a respective one of the rotary directions of the motor (97).

Abstract: A rotary tower crane for construction purposes comprising a non-rotating mast, a boom mounted at the head of the mast by a rotary connection so as to be swingable about the mast axis, a lifting device on the boom consisting of a hoisting rope which can be raised and lowered, and a distributor device for supplying and distributing concrete in the working area of the crane. The distributor device comprises a platform mounted on the mast below the rotary connection, an articulated distribution arm serving as a carrier structure for a concrete conveyor pipe formed in a plurality of sections connected together by ram-actuated connections, and having a rotatable mounting located on the platform. The platform is mounted on the mast by a ram-actuated rotational coupling so that the platform may be swung about an axis parallel to the axis of the crane mast to provide an operational field for the platform which is limited by the extent of swing of the platform on both sides of the crane mast.

Abstract: Apparatus for distributing concrete comprises a jib rotatably mounted on a tower, with a conveyor pipe line mounted on the end thereof so as to be movable about horizontal and vertical axes. The pipe line is formed in several sections which are connected one below the other by pivotal joints with horizontal axes.