GB175325A - An improved lifting and dumping or ring discharge grab - Google Patents

Abstract

175,325. Cooper, H. M., and Willmott, H. B. Sept. 14, 1920. Grab-buckets.-In a grab of the type comprising, as shown, a bucket cross-head g and a hook-carrying crosshead k mounted to slide vertically in a guide-frame n, the cress-heads are coupled or uncoupled by a pivoted hook o adapted to turn mouth downwards when free, an eye h on the bucket cross-head being adapted to turn the hook into coupling position. Levers p, q, Fig. 5, retain the hook in coupled position or release, it therefrom, and the opening movement of the bucket jaws d is steadied by screws t, Fig. 8, working in nuts mounted on bars i of the bucket cross-head, the bars being slidable in the frame and capable of being lowered below the frame. The bucket jaws are pivoted on wings of the frame c and are connected to the cross-head g by pivoted links f. As shown in Fig. 5, the lever q pivoted on the lever p permits a shoulder p<3> thereon to remain in engagement with a shoulder o<3> on the hook o while passing upwards through the releasing-ring, but when passing downwards through the ring the lever q is raised and raises the lever p about its pivot p<1>, permitting the hook to turn by gravity into the position shown in broken lines. The lever p may be operated by a vertically guided weight v when the grab is resting on the ground. Hauling on the rope passing round pulleys l, m in the cross-head and frame closes the jaws when in the position, shown in Fig. 1, and the grab is raised. On lowering, the ring operates the levers and the jaws are opened to discharge the grab. The cross-head g carries nuts s, which are either rotatable on the screws t and geared with pinions braked by spring washers, or the nuts are fixed, the screws being then rotatable and braked.