GB1360190A - Lifting beam - Google Patents

Abstract

1360190 Self-levelling beams; lifting arrangements HARLAND & WOLFF Ltd 14 June 1971 [15 March 1970] 45413/69 Headings B8H and B8B A lifting beam which is suspended from a crane (not shown) and which is able to regain its original orientation relative to the crane after tilting when loaded comprises a beam proper 11 and a trolley 19 which is attached to the crane by means of yoke arms 16, 17 which are pivotally mounted on a yoke 13 which is pivotally connected to a single suspension member 14 of a crane hoist block 12, the beam proper 11 being movable relative to the trolley 19 by engagement with trolley wheels 20, 21 under the action of a motor 27 which drives a worm 23 engaged in a nut 26 fixed on the trolley 19. When the beam 11 tilts relative to its original orientation a sensing device 29 (e.g. a spirit level, pendulum or electric motor) actuates the motor 27 and thus the worm 23 to move the beam proper 11 relative to the trolley 19. The load (not shown) is slung from the beam proper 11 by means of a load compensating means comprising a rope 31 which extends around pulley blocks 35 and sheaves 34 and also around a drum 36 which is spring biased out of engagement with a braking element 38 when the pulley blocks 35 are unloaded. A turning mechanism 15 is connected to the member 14 to enable the yoke 13 and thus the beam to turn about a vertical axis of suspension relative to the hoist block 12. Thrust fans 51, 52 are mounted at the ends of the beam proper 11 to turn it about the said vertical axis.