GB275055A - Improvements in and relating to automatic crane grabs - Google Patents

Abstract

275,055. Gerdes, F., and Gerdes, F. Nov. 15, 1926. Lifting-dogs; load, engaging and depositing.- The gripping or lifting arms 15 are pivoted in the frame 1 at A and are moved automatically to engage and release the load by a ram 2 free to slide in the frame. When the frame is lowered and the plate 3 rests upon the load, the frame 1 moves downwards on the ram 2 and a pawl 5 carried by the ram engages a star-wheel 8 carried by the frame so as to turn the cams 9, 10 through 90‹. The cams raise the bridge 11 which is connected by links and levers to the arms 15. On lifting, the frame 1 moves upwards on the ram, and the pawl comes into position for engaging the next tooth of the star-wheel 8. On setting down the load, the frame moves downwards on the ram 2 and the cams 9, 10 are moved so as to lower the bridge 11 and swing the arms 15 outwards. The cams 9, 10 may be constructed so as to move the bridge positively in both directions. The pivots of the arms 15 may be adjustable in the frame. The shackle 16 at the head of the frame is shaped so as to bring bell-crank levers 18 into engagement with the pulley-block 42 when the shackle becomes vertical on lifting, whereby the load is prevented from swinging relatively to the block. In a modification, Fig. 4, gripping-arms 19 are pivoted on the shaft 24 and connected by links 21 with the lifting-head 22 of the frame. A ram 28 is free to move up and down in the frame, and carries pawls 32 to engage star-wheels 27 carried by the frame, so as to turn cams 26 through 90‹ on engaging the load and on setting it down. The cams 26 control the position of two hooked levers 34 pivoted in the frame. In the position shown, on lifting the crane-hook, the hooked ends of the levers 34 will engage lifting bolts 33 in the frame and lift the tongs by their pivot pin with the arms open. On lowering on to a load, the ram 28 moves in the frame and the cams are turned so as to push the levers 34 apart, and on lifting the tongs close against the load while the ram falls and the pawls come beneath the next tooth of the star-wheel. On setting.down the load, the cams are again moved and the levers 34 come into position to lift the open tongs away from the load. The spindle 25 of the star-wheel may carry an indicating dial, which may bear against a spring to prevent accidental movements of the cams. Wheels 38 are provided on the arms 19 for movement over the ground or on rails.