GB381928A - Improvements in or relating to lifting and launching devices - Google Patents

Abstract

381,928. Cranes; boat raising and lowering gear. STOTHERT & PITT, Ltd. and PITT, R. B., Newark Works, Bath. July 11, 1931, No. 19990. [Class 78 (iv).] In cranes or like apparatus intended primarily for lifting and launching seaplanes, boats, &c. in a rough sea, means is provided for taking in the slack of the ropes as the load is raised by the waves and holding the load in the raised position, and for releasing the ropes for lowering when desired. As shown, the hoisting ropes 5 of a slueing cantilever crane are led from the drum 4 over sheaves 6 on the trolley 7, round the fall block 8 and the sheaves 9 on the trolley, and over sheaves 10 at the end of the jib to a barrel 11. A weight 15 hangs in the bight of a tail rope 12 on the barrel 11 which is held by a brake disc 17 when the ropes 5 are payed out for lowering the block. When the brake 17 is released, the weight 15 falls taking up any slack in the ropes 5 and the barrel 11 is held in the new position by the engagement of a ratchet wheel 18 with a pawl 20 on a brakedisc 19. For lowering a boat &c., the weight 15 is initially near its lowest position, and the brake-disc 19 is held fast while the boat is lowered to the crest of the waves ; the brakes are both released to launch the boat under control by the weight 15, and the brake disc 17 is then held while the ropes 5 are payed out to release the falls. In a modification, Fig. 3 (not shown), the gear is applied to a jib crane with a single hoisting rope.