| 摘要 |
PROBLEM TO BE SOLVED: To provide a convenient file for board cutting. SOLUTION: A first protrusion group 110A (120A) and a second protrusion group 110B (120B) that are each comprised of a plurality of cutting protrusions 111, 121 (112, 122), are alternately arranged on a file body 1 in a cutting direction of the file body 1. The cutting protrusions 111 (121) of the first protrusion group 110A (120A) and the cutting protrusions 112 (122) of the second protrusion group 110B (120B) have cutting surfaces 111a, 121a (112a, 122a) which are mutually oppositely directed. COPYRIGHT: (C)2010,JPO&INPIT
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