| 摘要 |
PROBLEM TO BE SOLVED: To provide a head part structure of a fastening body capable of surely using a spanner and a bar wrench.SOLUTION: In a head structure 1 in a male screw body 10 having a head part 20 and a shaft part 40, the head part 20 includes: an outer peripheral surface 26 of which an outer shape in a cross section vertical to an axial line G of a male screw part 42 is a polygonal shape of which the number of apexes is n; and a polygonal holes 30 of which an inner shape in a cross section vertical to the axial line of the male screw part 42 has apexes of which the number is an integral multiple of n.SELECTED DRAWING: Figure 1 |
