| 摘要 |
PROBLEM TO BE SOLVED: To provide a drain plug which has excellent water-discharge property without requiring a sand stop cover for drainage, enables the easy replacement of water cut-off packing and drain packing, and is free from intermediate leakage of water. SOLUTION: The fitting part between a plug body and an outer tube is formed in an intermittent fitting to form a space (gap), and drain ports formed in the outer tube are eliminated to provide a drain plug with the function of a sand stop cover. A water cut-off block 3 detachably fitted to the lower spindle of an operation part and having a drain passage therein comprises a water cut-off packing 2 covering the end of the block and a drain packing 4 facing the water cut-off packing at an interval. The water cut-off packing and the drain packing are formed integrally with the water cut-off block by bonding or baking. The water cut-off packing 3 is composed of a center projecting part covering the end and a peripheral part joined at right angle to the projecting part. A groove of U-shape in cross section is formed in the peripheral part at a portion in contact with the projecting part. The outer surface of the projecting part is partially rounded. The drain packing also has a groove of U-shape in cross section in the peripheral part in contact with the projecting part. COPYRIGHT: (C)2008,JPO&INPIT
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