GB564157A - Improvements in or relating to lifting cranes or hoists - Google Patents

Abstract

564,157. Cranes; skip hoists. WILSQN, S., and ELLIOTT, J. B. Nov. 4, 1942, No. 15571. [Classes 78 (iii) and 78 (iv)] A crane or hoist comprises a frame, a jib 41 on said frame carrying a hoist block 64, a skip 46 movable along the jib, and a single actuating means for raising and lowering the hoist block and the skip. In the construction shown in Figs. 1 and 2, a crane jib 41 is mounted on a self-propelled wheeled or endless-track chassis 10, the jib being pivoted at 42 to the chassis so chat when it is vertical rails 44 for a skip 46 are in line with rails 43 on a frame member 40 fixed to the chassis and the skip can pass to and from the member 40 and the jib. A motor 13 on the chassis is used for propelling the crane, luffing the jib, and raising and lowering the hoist block 64 and the skip 46. The motor may be reversible, but preferably drives a shaft 21 through reversing gearing clutches 19, 20 controlled by a reversing lever 26. The rear wheel 12 of the crane is driven from the shaft 21 through chains 29, 33 and a clutch 36 controlled by a pedal (not shown) which also controls the brakes on the front wheels 11 so that the brakes are " on " when the clutch is disengaged, and vice versa. The jib is luffed by means of a rope 51 wound on a drum 50 which can be coupled to the shaft 21 by a clutch 61 controlled by a luffing lever 62. The jib is prevented from luffing back beyond the vertical position by a stop 63. The luffing rope passes over pulleys 52 on a fixed framework 54 and pulleys 53 on the jib. The load block 64 and/or the skip 46 are raised and lowered by a rope 68 wound on a drum 65 which can be coupled to the shaft 21 by a clutch 66 controlled by a hoisting lever 67. As shown in Fig. 4, the hoisting rope 68 passes over a pulley 69 near the pivot 42 of the jib, over a pulley 70 on the jib head, down over pulleys 71, 71a on the skip carriage 45, up and over pulleys 72, 73 on the jib head and the load block 64 respectively, and is finally anchored to the jib at 74. With the idler pulley 69 located near the jib pivot 42, level luffing is obtained. The block 64 is lighter than the skip carriage 45 so that when the rope 68 is wound on the drum 65 the carriage stays down and the block 64 is raised until it reaches its upper position against the jib head. If the rope is still further wound on the drum and the jib rails 44 are in line with the fixed rails 43, the skip carriage is raised to any desired height on the jib. The skip carriage may be locked on the fixed frame 40 so that the hoisting rope 68 can be used in the usual way to raise and lower the load block 64 ; the carriage may also be held in any desired position on the jib by pins or other suitable means. The skip 46, Fig. 5, is preferably detachably connected tb the carriage 45 which has rollers 47 running on the rails 43, 44. Hooks 110 on the skip engage over a pin 83 on the carriage and the top of the skip is secured by latches 113 pivoted to bars 115 which are themselves pivoted to the carriage on the pins 83 and are secured by a pin 116 to a bracket 118. The skip, when detached from the carriage, may be suspended from the load block 64 by an inverted L-shaped lever provided with pins 83 and a stop plate to take the place of the latches 113. Modifications are described in which : (1) the jib can fold back over the top of the chassis under the action of a counterweight when the luffing rope is paid out ; when the luffing rope is wound on the drum 50 an arm pivoted to the jib is moved forwardly and raises the jib from the rearward or folded position to any desired working position ; (2) the jib may be fixed, comprising a vertical part and an upper horizontal part.