| 摘要 |
PROBLEM TO BE SOLVED: To provide a screw with driving hole for surely transmitting large driving force with a relatively shallow driving hole. SOLUTION: The screw is constituted of a head part 2 having the driving hole 10, and a leg part 4 formed integrally with the head part 2 and having a ridge 3 therein. In the screw with driving hole, engagement grooves 11 of the driving hole 10 are arranged radially from the center of the screw and circumferentially at equal intervals, each bottom face 13 of the engagement grooves is constituted of a steep slope 13a and a gentle slope 13b, and the area of each engagement wall 12 of the engagement grooves 11 is enlarged. Therefore, compared with a bottom face constituting the engagement groove in a shape of circular arc, management such as measurement of the molding depth depending on the dimension of the screw, in heading molding of the engagement groove is easy. In manufacturing a punch for molding the head part used for the heading molding, its process is facilitated to lower the manufacturing cost. A driving area of the engagement wall becomes large, and the engagement groove is not broken even if large driving force is applied thereto. COPYRIGHT: (C)2005,JPO&NCIPI
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