ES357623A1 - Load stabilizer crane forks with automatic clamping device - Google Patents

Abstract

A crane hook, Fig. 3, has load-supporting forks mounted on a carriage 104 which is raised by a lifting cable 106 so that the load is clamped between top members 102 and the forks. Fig. 4 shows an arrangement in which the members 102 are pulled down towards stationary forks. When the fork shown in Fig. 3 is set down unloaded, a plate 21, Fig. 5, moves downwards and turns levers 18 overcentre through links 12, 13, 20. This pivots arms 17 to the position shown in Fig. 6 and the fork may be loaded up. When the loaded fork is lifted, the plate 21 lifts spring-loaded one-way extension pieces 19 without moving levers 12, and passes between jaws 25, thus causing the forks to rise and grip the load. When the weight of the load is released, the plate 21 moves down to position C, Fig. 6, and pushes the levers 18 back to the Fig. 5 position. The fork is now unloaded and when it is next raised prongs 22 on the plate 21 engage holes 23 in arms 17, thus holding the arms together and preventing upward movement of the plate 21 and the lifting forks. Fig. 7 shows an embodiment in which the members 218 mounted on a carriage 211 are pulled down to clamp the load. Toggles 210 on a movable plate 129 automatically engage either the carriage 211 to hold the members 218 up for loading, or, engage and raise a pulley block 213 to pull the carriage 211 down to clamp the load. A carriage 128, which supports pulleys 220, is slidable along guides 219 by a hand wheel 223 and worm and nut mechanism. Figs. 11-16 (not shown), show a different arrangement of the cable clamping means and toggle plate of the embodiment described with reference to Fig. 7. The tips of the forks in all embodiments may be either provided with rollers to facilitate load engagement or with sleeves carrying rollers.