| 摘要 |
PROBLEM TO BE SOLVED: To enable sediment to be surely grasped by a hammer grab for use in the excavation of a vertical shaft. SOLUTION: A wedge surface 41, which is gradually protruded downward, is provided on the peripheral surface of the movable frame 8 of the hammer grab 1. When the movable frame 8 is pulled up by means of a hanging wire 22, a sliding block 30 is protruded outward by the wedge surface 41, and a pressing plate 36 of the sliding block 30 is pressed against the inner wall surface of a casing C, so as to inhibit lift when the sediment S is grasped by a shell 17 of the hammer grab 1. COPYRIGHT: (C)2007,JPO&INPIT
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