| 摘要 |
PROBLEM TO BE SOLVED: To transmit the torque of a lock driver to a screw enough to surely lock the screw without breaking the groove(s) of a screw head. SOLUTION: In this lock screw 1, a minus groove or plus grooves such as a groove(s) formed on the screw head section 2 of a bolt or a wood screw is formed into a shape of a dovetail groove 3. In this case, a recessed section 7 for positioning is formed in the center section of the dovetail groove 3. A lock driver 4 has a tip section 9 which broadens toward the tip having nearly the same shape as that of the dovetail groove 3. A projected section 8 for positioning is formed in the center section of the tip broadened section 9.
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