GRAB-BUCKET FOR USE IN UNLOADING IRON-ORE AND A METHOD OF UNLOADING IRON-ORE

摘要

1439224 Grab buckets KOBE STEEL Ltd and MITSUBISHI JUKOGYO KK 18 June 1973 [19 June 1972 19 Oct 1972] 28832/73 Heading B8H [Also in Division B1] A grab bucket for use in unloading iron ore from the hold of a ship comprises an upper frame unit 20 which is attached by means of suspension cables 19 to a crane, a lower frame unit 21 on which the bucket jaws 23 are pivotally mounted, the unit 21 being movable relative to the unit 20, the unit 21 being connected by means of cables 18 which pass through the unit 20 to a traction means (not shown) and when the grab bucket is lowered by the crane towards the ore to be unloaded the jaws 23 open under gravity and are closed on raising the frame unit 21 by means of the cables 18 to trap a quantity of the ore between the jaws 23, each of the jaws 23 having teeth 25 on their mating portions 24 which intermesh when the jaws are closed. The ratio of the weight (W) of the grab bucket to the inner volume (V) of the bucket jaws in their closed position is in the range from 3À0 to 6À0 ton/cubic metre, and the ratio of the grab bucket weight (W) to the effective width (2B) of the jaws 23 (where B is the width of each jaw as shown in Fig. 4, not shown) is in the range from 40 to 60 kg./cm. Struts 22 connect the jaws 23 to the frame unit 20. As shown in Fig. 6b (not shown) when the grab bucket is lowered on to the ore in its open condition the teeth 25 penetrate and demolish the upper surface of the ore to enable the jaws 23 to move through the ore into their closed condition.