Slide mechanism for expandable bit screw holding screwdriver

In an expandable bit screwholding screwdriver comprising an elongate shank including a pair of shank elements, having blade tips formed at one end, movable between a position whereat the shank elements diverge outwardly such that the blade tips lie in a blade thin state and a position whereat the shank elements are in alignment such that the blade tips lie in a blade thick state;

• and, a slide mounted on said elongate shank for longitudinal movement toward and away from said blade tips, movement toward said blade tips causing said shank elements to move from a divergent position toward an aligned position, the improvement comprising:
• guide means formed in said elongate shank, said guide means including a helical path;
• and,
• elongate guide follower means formed in said slide, said guide follower means including first and second shaped apertures spaced along the longitudinal length of said slide, said first of said shaped apertures surrounding said shank elements between one end of said helical path and said blade tips and said second of said shaped apertures positioned adjacent to said helical path, said second shaped aperture formed such that longitudinal movement of said slide toward said blade tips causes said slide to rotate about said shank, as a result of coaction between said helical path and said second shaped aperture, said rotation being in one direction when said slide is moved toward said tips and in the opposite direction when said slide is moved away from said tips, said first shaped aperture formed such that it coacts with said shank elements to move said shank elements from said divergent position toward said aligned position when said slide rotates as it moves toward said blade tips and from said aligned position toward said divergent position when said slide rotates as it is moved away from said blade tips.

An expandable bit screw holding screwdriver comprising:

• an elongate handle;
• an elongate shank extending coaxially outwardly from one end of said elongate handle, said elongate shank including a pair of shank elements having blade tips formed at one end thereof, said shank elements being movable between a position whereat said shank elements diverge outwardly such that the blade tips lie in a blade thin position and a position whereat the shank elements are in alignment such that the blade tips lie in a blade thick position, said elongate shank further including a helical path formed in its outer periphery;
• and,
• a slide mounted on said elongate shank for longitudinal movement toward and away from said blade tips, said movement toward said blade tips causing said shank elements to move from said divergent position toward said aligned position and movement of said slide away from said blade tips causing said shank elements to move from said aligned position toward said divergent position, said slide including first and second shaped apertures spaced along the longitudinal length of said slide, said first shaped aperture surrounding said shank elements and said second shaped aperture adapted to follow said helical path as said slide is moved toward and away from said blade tips, said following action causing said slide to rotate in one direction or the other depending on the longitudinal direction of slide movement, said rotation causing said first aperture to move said shank elements between said aligned and divergent positions.