Abstract: A telescopic boom includes three or more sections which may be pivoted if desired. The innermost section is incapable of moving in the longitudinal direction, whereas the other sections are adapted to be concurrently dislocated in the longitudinal direction relative to each other. Only a drive mechanism on the innermost section is adapted to be actuated from an outside source, whereas the other sections are driven by the relative motion of the sections movable in the longitudinal direction.

Abstract: In a method and an apparatus for putting down or taking up a load from or upon a loading location by way of a crane, wherein the crane or the loading location is subjected to substantially irregular vertical movements which change the distance between the hoisting hook of the crane and the loading location, there is accomplished a preferably continuous measuring of values which give information about the distance and relative velocity between a point on the crane and the loading location. The measuring signals are treated and possibly converted so as to create regulating signals which influence the velocity of the hoisting hook and/or the position of the crane to impart to the hoisting hook an acceleration or retardation as a compensation for the said irregular movements, so that the relative movement between the load and the loading place will follow the course desired by the operator, without undesired powerful collisions between the load and the loading location.