Device for locking and releasing a screw bit

A screw bit positioning device comprising:

• a tube having a passage defined axially therethrough and a polygonal inner periphery defined in a first end of the tube so as to be adapted to engage a screw with the polygonal inner periphery, the polygonal inner periphery sharing a common axis of the axial passage, a first hole and a second hole respectively defined through a wall of the tube, a C-shaped clamp securely mounted on the tube and located between the first and second holes, a first bead movably engaged with the first hole and a second bead movably engaged with the second hole;
• a movable member movably received in the passage and having a first end facing the first end of the tube, a first spring received in the tube and having a first end contacting a second end of the movable member, a second end of the first spring contacting an end of a connection rod inserted into the second end of the tube, the movable member having a groove defined in an outer periphery thereof, and
• a sleeve movably mounted to the tube and a flange extending from an inner periphery of the sleeve so as to define a first space and a second space, the first hole communicating with the first space and the second hole communicating with the second space, the C-shaped clamp located in the second space and a second spring mounted to the tube and biased between the C-shaped clamp and the flange, a collar securely connected to the sleeve and engaged with the second space.