GB820811A - Improvements in overhead grabbing crane - Google Patents

Abstract

820,811. Opening and closing grabs; winding. McKIERNAN - TERRY CORPORATION. Nov. 5, 1956, No. 33738/56. Classes 78 (4) and 78 (5). The grab holding and closing ropes of an overhead grabbing crane are in one continuous length terminating at one end in a storage reel so that fresh rope may be fed into the system to replace worn rope taken out at the other end, without changing all of the rope. Grab changing is also facilitated. A pulley 10, Fig. 1, incorporated in the hoisting drum 11 with its axis at right angles to that of the drum and normally locked against rotation by a rope clamp 17, divides the rope into holding and closing lines 12, 13. Line 12 passes from the drum 11 via pulleys 18, 19, 20, 21, 22 and a releasable anchor 15 to the storage reel 16, and line 13 via pulleys 23-31 inclusive to the grab closing drum 14. Pulleys 19, 21, 24, 30 are on a trolley 33 movable along the jib by a rope 34, and pulleys 20 and 25-29 are on the grab 32. Most wear occurs where line 13 passes over pulleys 25-29, and by fixing the grab in an open position, then running all the rope off the drum 11 so that the line at this point passes round the pulley 10 only, and releasing the clamps 15, 17, fresh rope may be fed into the system from the reel 16 and worn rope removed from the drum 14. Reeving a fresh grab.-The grab may be changed by disconnecting the rope at the drum 14 and connecting its end to a reel 52 carrying a rope with a removable tag line which may then be fed into the system, while taking up the slack on the reel 16, until the tag line is in position to change first the closing line, then the holding line on to a new grab ready placed in position with tag lines threaded. Winding.-Fig. 7 shows the arrangement of the pulley 10 in the drum 11. Shoulders 41 on removable covers 43 normally guide the two reaches of the rope towards the middle of the drum, but on removal of the covers 43 the rope takes up the reeving position shown at 12, 13.