GB1358768A - Anti-pendulating lifting cranes - Google Patents

Abstract

1358768 Anti-pendulating cranes HAGGLUND & SONER AB 23 Sept 1971 [24 Sept 1970] 44306/71 Heading B8B [Also in Division F1] A crane with a jib 4 carrying a load 11 is slewed in the normal way by an hydraulic pump 13 supplying an hydraulic motor 14 via a valve block unit U which includes a selector valve 15, four non-return valves 16, 17, 18, 19, a pressure limiting valve 20 and a control valve 21. Outside the unit U is a further pressure limiting valve 22. The motor 14 is braked by a cylinder 23. Supplementary apparatus for damping pendulation is represented by the block V which includes a pendulation damping valve 24, two actuating valves 25, 26, braking valve 27 and a non-return valve 28. Pressure is applied to the block V through line 55, control pressure through line 47 and supply pressure through line 48. Operation of the pendulating damping valve 24, after the jib 4 has been slewed to a desired position, moves it from the position shown to allow pressure from the line 55 to enter the line 56. Control pressure from the line 47 holds the valve 25 so as to allow the pressure from line 56 to pass through line 60 to act against the control pressure in line 51 to move valve 26 into its left position. The valve 27 is moved by the pressure from line 55 through line 57 augmenting the control pressure acting through the line 50 to allow the supply pressure from line 48 to pass through the line 52 to the cylinder 23 to hold the brake off. Reduction of pressure in the line 42 due to the position of the valve 26 allows the pressure limiting valve 20 to open. By the short-circuit obtained: lines 29, 30, 36; valve 16; lines 37, 39; valve 20; lines 62, 63; valve 19 and lines 34, 31, 32 the motor 14 can move freely to allow the still moving load to pull the jib 4 to turn the crane so that kinetic and static energy possessed by the load is dissipated by the friction of the crane, thereby damping movement of the load. The damping of pendulation can also be performed during full speed slewing by the above-described disengagement the slewing machinery allowing the crane to continue to turn by its own kinetic energy and that of the load 11 until its slewing motion stops. In a similar manner to the above an overhead bridge crane (not shown) with a crab carrying a load can utilize the friction of the crab to damp pendulation of the load.