SEMI-INVERSE SCREW THREAD REMOVAL SCREW

摘要

PROBLEM TO BE SOLVED: To prevent slippage when a screw is removed.SOLUTION: This invention relates to a semi-inverse screw thread removal screw 1 including a screw bolt 1.1, a screw head 1.2 and a recess hole formed at the screw head 1.2. Then, a lower stage portion of the recess hole is a polygonal hole structure or I-shaped form and an upper stage portion of the recess hole is formed with a screw thread 1.4 in an inverse direction to the screw thread formed at the screw bolt 1.1.SELECTED DRAWING: Figure 1