Luffing and slewing jib crane

Claim 1

A crane having load cable means and a load attachment comprising a first member suspended from the crane by reaches of said load cable means, a second member, means for securing a load to said second member, means connecting said second member to said first member for rotation of said second member relative to said first member about a vertical axis, power-operated means for effecting said rotation, the said cable reaches being so spaced apart relative to the crane and said first member as to effect resistance to, and restrict, reactionary rotation of said first member resulting from the action of said power-operated means, pulley means on the crane and on said first member with which said load cable reaches cooperate in such a way that the load is substantially maintained in proper trim while being raised, moved, turned and lowered by the crane, said load cable reaches being formed by a single length of load cable so as to be selfaccommodating in regard to their respective lengths, winch means for said cable, said cable having its ends connected to the winch means and passing in two runs to the pulley means on the crane, the said runs then being reeved upward and downward around and between said pulley means on the crane and said pulley means on said first member, said cable finally forming a terminal loop reeved around at least one pulley of said pulley means, said crane having a jib free at one end, an outrigger on the free end of the jib and extending to opposite sides thereof, said pulley means on the crane being located on the jib and on said outrigger, said load cable being reeved around the pulley means on said outrigger to form said terminal loop, said pulley means on the crane comprising a pulley mounted on each sIde of the jib adjacent the free end thereof, a pulley at each end of said outrigger, and two pulleys mounted on each side of the jib and located intermediate the end of the jib and said outrigger, the pulley means on said first member of the load attachment comprising a series of four pulleys connected at spaced intervals to said first member adjacent each end thereof, said load cable runs being reeved first around one of said intermediately located pulleys on each side of the jib, then downward to said first member and around the inner pulleys of the series of pulleys nearer to the jib and then to the series of pulleys remoter from the jib, then upward to and around the other said intermediately located pulleys on the jib, then to and around the pulleys adjacent the end of the jib, then downward to said first member and around the outer pulleys of the series of pulleys remoter from the jib and then around the series of pulleys nearer to the jib, and finally upward to said outrigger at which said runs form a terminal loop reeved around and extending between the pulleys at the end of said outrigger.