GB1273541A - Improvements relating to jib cranes - Google Patents

Abstract

1,273,541. Erecting mobile jib cranes. W. F. VONCK. 20 May, 1969 [21 May, 1968], No. 24139/68. Heading B8B. A jib crane, Figs. 1, 3, comprises a chassis 1 with spaced super-structure support areas 3, 4, 4 constituting the turntable for the crane. In the stored position of the telescopic jib 6, 7, 8, 9, it is supported by both the areas 3, 4 with its lower end adjacent the area 3. To erect the crane the left-hand end 7A of section 7 is separated from the area 3 (which may be a counterweight) and the sections 7, 8, 9 slid through 6 to an intermediate cantilevered position, Fig. 2 (not shown), by operating telescoping winch 13. Latches (not shown) are then automatically released enabling the telescoped sections 8, 9 to be extended, after the jib is inclined to an appropriate angle about pivot 6 using derrick winch 19, by the winch 13, Fig. 3. In a second embodiment, Fig. 6 shows the first stage of erection of a tower crane, jib section 33 having been unfolded from alongside section 32. Derrick winch 42, Fig. 7A, is first operated slightly to raise the upper end 30B of the tower 30, whereafter telescoping winch 38 is operated to pull the tower foot 30A towards the turntable 4, simultaneously paying out cable into the derrick cable. During this movement rollers 45 engage guide rails 46 which guide the tower foot 30A into its operational position where it is latched against further sliding movement. The derrick winch 42 is then operated to draw the tower 30 upright against heavy springs (not shown), (which assist in collapsing the crane), where it is latched or pinned in place. The jib 31 is then turned horizontal by attaching load hook 60, Fig. 11, to the turntable 4 and simultaneously pulling in hoist cable 61 and paying out cable from the derrick winch 42, Fig. 12 (not shown). This embodiment may be used as a derricking jib crane by leaving the jib 30 latched alongside the mast 30, the combination being used as a jib.