Patent ID: 7249544

Claim:
A screw holding type screwdriver bit having, at a tip end of a shaft portion thereof, a plurality of blade portions formed with a substantially perpendicular end edge portion at a tip end of each one of said plurality of blade portions, said screwdriver bit being for a screw having a bit engagement groove of a shape selected from the group consisting of cross, a three way form and polygon, wherein said screwdriver bit comprises: a cut out portion formed by cutting out one of said plurality of blade portions in a direction of an axis of said screwdriver bit; a guide passage formed by cutting out a part of said shaft portion of said screwdriver bit for a predetermined length extending from said cut out portion; a protective sleeve provided on and so as to surround an outer circumference of said shaft portion, in which said guide passage is formed, with tip ends of said blade portions partially exposed; and an elastic piece inserted and disposed between said guide passage extending from said cut out portion and said protective sleeve so that a tip end of said elastic piece, together with said blade portions, is exposed from said protective sleeve and said elastic piece is offset in a circumferential direction with respect to said cut out portion, and wherein said guide passage has a width slightly greater than a thickness of said one of said plurality of blade portions which is cut out, and said elastic piece is inserted and disposed in said guide passage with a part of said elastic member bent in a circumferential direction of said shaft portion; said protective sleeve is fastened, by crimping, at a mounting end thereof to a cut-out formed on an outer circumference of said shaft portion, and a rear end of said elastic piece is contacted to and engaged with an inside of said mounting end of said protective sleeve; and the tip end of said elastic piece, when engaged with a bit engagement groove of said screw by an elastic force that acts in a direction opposite from a screw tightening direction of said screw, holds said screw.