Abstract: The free end portion of the boom of a crane is detachably coupled to a flat rectangular carrier for a collapsible gallery. The carrier can pivot about an axis which is normal to the longitudinal direction of the boom to and from a position adjacent to one side of the boom, and the collapsed gallery can be pivoted to a position outwardly adjacent to the carrier when the latter is adjacent to one side of the boom. This renders it possible to move the crane without detaching the carrier and the gallery from the boom. The flat sections of the gallery are collapsible into planes which are parallel to the pivot axis between the gallery and the carrier.

Abstract: The boom of a crane carries a pivot bearing for a second bearing which guides an elongated column. The upper or the lower end of the column supports a gallery which is turnable about its axis. The second bearing is pivotable about the horizontal axis of the pivot bearing by a cylinder-piston unit and the column is movable lengthwise with respect to the second bearing by means of the crane cable.

Abstract: The free end portion of the boom of a crane carries a separable pivot bearing defining a horizontal pivot axis for a second bearing which reciprocably guides an upright column for one or more galleries. When the cable which is used to lift or hold the column breaks and the column begins to rapidly descend, such movement of the column activates a composite brake mounted on a frame surrounding the column at a level above the second bearing. The brake holds the column against downward movement with reference to the frame whereby the frame tends to descend toward the second bearing against the opposition of several shock absorbers which reduce the likelihood of damage to and/or excessive swaying of the boom and/or injury to the occupant or occupants of the gallery. The speed of downward movement of the column is monitored by a detector which activates the brake as soon as the speed exceeds a preselected value.

Abstract: The boom of a crane carries a pivot bearing for a second bearing which guides an elongated column. The upper or the lower end of the column supports a gallery which is turnable about its axis. The second bearing is pivotable about the horizontal axis of the pivot bearing by a cylinder-and-piston unit, and the column is movable lengthwise with respect to the second bearing by the crane cable.