The working Principle of the Hydraulic Crane

 Hydraulic Crane:-


A hydraulic crane consists of a central pedestal supporting a mast from which is attached a jib or ram. The jib can be raised or lowered to reduce or increase the radius of action of the crane. The mast can revolve about the vertical axis so that jib with load can be positioned anywhere in a circular area around the crane. Thus, both by lowering or raising the jib revolving around the pedestal,  the load can be moved to any place within the crane area action. there are two sets of pulleys include one which is stationary and the other which is moveable. The load is suspended by a wire rope that passes over a guide pulley fixed on the jib and on another end the wire rope is attached to the hydraulic jigger. The jigger consists of a fixed pulley. at the bottom end of the fixed cylinder is attached to a movable pulley. At the bottom end of the fixed cylinder is attached to a fixed pulley. The jigger is attached to the mast. The wire rope to the jigger passes over the movable pulley and the fixed pulley before it is fixed to the jigger. High-pressure water is admitted in the cylinder of the jigger which fore the ram out, thereby increasing the distance between movable and fixed the pulleys of the jigger. This causes the wire rope on the guide pulley to move up, thereby lifting the load. When water is removed from the cylinder causing the ram to move down, then the decrease the distance between the movable and fixed pulleys. The load on the guide pulley is lowered as the length of the wire rope increases. The crane has generally got a velocity ratio of 4:1 which means that the load on the wire rope moves four times transfers to the speed of the ram in the jigger.



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