Abstract: For use with apparatus for transferring a load between two stations movable relative to each other in a vertical plane by means of a crane carried by one of the two stations having a hook assembly for attachment to the load on the other station for lifting the load, a lift-off indicator measures either the relative velocity or relative vertical accelerations of the two stations and from signals representing relative velocity of approach showing values between a maximum positive and a negative, and relative acceleration acting away from the direction of approach indicates conditions suitable for initiating lifting.

Abstract: Control of vertical motion of a suspended crane hook assembly to accommodate vertical motion between a station carrying the crane and a station carrying a load is achieved by a transducer on the hook assembly and a control cord depending onto the load station. Tension above a set value in the cord produced by a crew member on the station causes the hook assembly to descend and below the set value causes it to rise. Movement of the stations causes a continuous adjustment of tension and the hook assembly follows the motion, extra tension being applied to guide the hook assembly down to the load and vice versa.

Abstract: Apparatus for controlling deformation of an elongate member, such as a lattice girder, comprises a torque transmitting member, such as a hollow cylindrical tube, extending for the length of the girder coaxially with its longitudinal axis and fixed at one end to one end of the girder. The cylinder is free to rotate relative to the girder at its other end and is connected by hydraulic actuators to be rotated relative to the girder in response to the measurement of rotation between the ends of the girder. The relative rotation of the tube transmits torque to the fixed end and resists deformation of the girder.