| 摘要 |
PROBLEM TO BE SOLVED: To provide sure fastening of a bolt (4) according to thinning of a wood building material (5) of a wooden frame, even when the wood building material (5) is thinned by drying, by a high resiliency extension washer (1) which is deformed in an elliptic shape by being fastened by the bolt (4). SOLUTION: The pipe-like extension washer (1) formed of a high resiliency material such as high-carbon steel sheet or stainless steel sheet includes bolt holes (6) formed at two positions corresponding to side surfaces formed when the washer is made in the elliptic shape. According to the looseness of the bolt (4) caused by thinning of the wood building material (5) after fastening the bolt, the high resiliency extension washer (1) keeps the fastening without backlash peculiar to the looseness. COPYRIGHT: (C)2011,JPO&INPIT
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