To provide a washer which can enhance a corotation preventing effect.
The washer 10 is composed of a flat plate provided with a bolt inserted hole 11 in its center and has on surface coming into contact with a fastener a recessed portion 14 which comprises a plurality of linear shapes or curvilinear shapes, a plane portion 16 which is formed so as to cut off the recessed portion, and a protuberance 15 which is formed on end and both sides of the recessed portion. Thereby, a nonslip effect becomes higher and the corotation preventing effect can be enhanced because sense of the protuberance can be made in multi directions. Moreover, it is possible to form a plane portion as annulus or quadrangle with the recessed portion spaced apart from each other as predetermined.
JP2009144883A | 2009-07-02 | |||
JPS57146910A | 1982-09-10 | |||
JP2003172332A | 2003-06-20 | |||
JPS301322Y1 |
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