MOVING SPREADER FRAME BY HYDRAULIC JACKS

摘要

1453714 Spreaders RUBERY OWEN & CO Ltd 8 July 1974 [7 July 1973] 32473/73 Addition to 1326213 Heading B8H As described in parent Specification 1326213 a spreader frame 4 is movable horizontally relative to a carrier by means of an hydraulic jack 29 located at each end of the carrier 1 and connected to a pin 26 on the frame 4, the carrier 1 and spreader frame 4 being connected by means of suspension links 3. In the present invention when a load is to be picked up which is not centrally disposed beneath the carrier 1, one or both of the jacks 29 is or are actuated by means of an associated control valve 5, Fig. 2, connected to each end of the associated jack 29 so that the spreader frame 4 is then located directly over the load and the links 3 are then inclined to the vertical. The carrier 1 is now raised by hoist means 2, lifting with it the spreader frame 4 and load, both of which are offset relative to the carrier 1. A switch 13 is then closed to energise solenoid valves 8 whereby both ends of the jacks 29 are connected to a fluid reservoir T through conduits 9, 10 and the piston rods and pistons of the jacks 29 are freely movable in their cylinders such that the leverage exerted by the offset load causes the spreader frame and load to swing to a position beneath the carrier 1 in which the links 3 are again vertical, the piston rods of the jacks 29 moving therewith. By releasing the switch 13 the valves 8 are de-energised and the conduits 9, 10 are thereby disconnected from one another, such that the jacks 29 are locked hydraulically in this position.