GB737302A - Mobile slewing crane with collapsible jib - Google Patents

Abstract

737,302. Cranes with folding jibs. RHEINMETALL-AKT.-GES. Aug. 26, 1953 [Sept. 1, 1952], No. 23619/53. Class 78 (4). The jib of a mobile slewing crane is in sections 5, 6, 7 hinged together at 8, 9 to fold to the position shown in Fig. 5 in which the upper chord of one section, 6, rests on the roof of the cab 4 or on supports, such as rubber cushions on the roof. Each of the sections 5, 6 is of bell-crank formation so that the luffing rope 12 may be connected to one arm and hoisting rope 14 to the other; thus one rope serves for folding the section while the other restrains the movement of the section when it passes its position of balance. When the jib is to be folded it is first lowered to rest on a folding support 13 as shown in Fig. 1, the fastening 10 holding the end section 5 is removed, and this section is turned to the position shown in broken lines in Fig. 1 by the luffing cable 12, the hook 15 on the hoisting cable 14 being connected to a bolt 17 on the section to restrain its movement. The jib is then raised by the luffing cable 12 until it can be supported by a folding support 19 as shown in Fig. 3 when a fastening 11, Fig. 1, is removed and the hook 15 connected to a bolt 21 on the section 6 so that the hoisting cable 14 may control the descent of the section 6 onto the roof of the cab 4 when the luffing cable 12 has pulled the section past its centre of balance. The support 13 is then folded away. Unfolding is effected by the reverse sequence, the luffing cable 12 restraining the unfolding movement.