Patent ID: 9737977
Date: 2017-08-22
CPC Classifications: B25B

Claim:
1. A driver bit configured to be attached to a tool coupler of a rotating tool including a polygonal socket and locking balls arranged at least either of vertex positions of the socket and center positions of sides constituting the polygon of the socket, comprising: a tip on which a cross blade configured to engage a cross recess formed on a screw head is formed; a torque transmitting part having a polygonal outer circumference corresponding to the socket and being configured to receive the rotational torque from the rotating tool; and a locking groove which extends in the circumferential direction of the driver bit between the tip and the torque transmitting part and into which the locking balls enter when the tip is inserted into the socket, wherein the tip has four blade forming grooves that extend outwardly from a shaft center of the driver bit in directions orthogonal to each other as viewed in the direction of the shaft center, thereby forming the cross blade, the locking groove is continuous with ends of the blade forming grooves on the torque transmitting part side; and the blade forming grooves have center lines respectively passing centers of the blade forming grooves, and are arranged so that the blade forming grooves have bottom parts, at which they are connected with the locking groove, located inwardly of the outer circumference of the torque transmitting part, wherein the center line of each of the blade forming grooves is displaced from a line connecting the shaft center with each corresponding one of the vertex positions of the polygonal outer circumference and a line connecting the shaft center with the center position of each corresponding one of the sides of the polygonal outer circumference, as viewed in the direction of the shaft center.