Fecha de publicación: 31/07/1930 Fuente: WIPO "wine" Comprises a portable sledge frame a mast mounted upon such frame a boom mounted to extend across the head of the mast in such a manner that it may swing round horizontally and turn up and down upon a pivot a hoisting rope suspended from a pulley upon one end of this boom and carried in along the boom and down to the foot of the mast and then outward over suitably placed guide - pulleys an adjustable chain or like connection between the other end of the boom and the mast and a rope connected to this end and carried over a suitably disposed guide pulley and then connected to the hoisting rope and adjusted to provide for the boom being lifted at its hoisting end during the latter portion of the pull on the hoisting rope [ 2 figures 3 claims ].