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Description
An ordinary design of " Priestman " Grab is illustrated in the Figure is the hoisting and closing chain, which is fixed at one end to the drum B, and at the other to the crane hoisting barrel. The opening chain (or frequently wire rope) is attached to the head of the grab at c. The two jaws D D are hinged together by the strong central shaft E. The method of operation is as follows : The opening rope is held by the brake, and the hoisting chain is paid out; the shaft E thereupon falls, and the jaws open, as shown in dotted lines (see Figure).
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