To provide a driver bit capable of surely loosening a screw to remove even when not only an operation groove but also a corner part of a base end part of a fan-shaped wall are completely broken or deformed.
The driver bit 3 includes a tightening/loosening operation part 10 including five or more rib-shaped projections 11 which are radially protruded and formed toward the horizontal outer direction at the lower end of a bit body 8, and a valley groove 12 formed between adjacent rib-shaped projections 11. Each of the rib-shaped projections 11 is composed of a rib peripheral surface 13 formed in vertically cylindrical outer surface shape, and a pair of valley groove peripheral surfaces 14, 14 for sandwiching the rib peripheral surface 13 therebetween. A biting part 20 driven in a peripheral wall 7 of a damaged recessed part 6 is formed at a corner part of the lower outer edge of each of the rib-shaped projections 11 defined by the lower end surface of the rib-shaped projections 11 and the rib peripheral surface 13.
KAWAI SHINNOSUKE
JP2001162552A | 2001-06-19 | |||
JPS462080Y1 | 1971-01-23 |
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