Patent ID: 6904834

Claim:
A screw-belt advancing mechanism for advancing a screw-retaining belt on a screw driving gun, the screw-retaining belt supporting detachably a plurality of screws thereon, and having a plurality of engaging holes, each of the engaging holes being disposed between adjacent two of the screws on the screw-retaining belt, said screw-belt advancing mechanism comprising: a barrel unit that has a front end and a rear end adapted to be connected to the screw driving gun, that is adapted to receive a driving shaft therein, and that defines a longitudinal direction; a sliding unit connected telescopically to said front end of said barrel unit, movable in said longitudinal direction relative to said barrel unit between extended and retracted positions, and including a nose plate; an urging member for urging said sliding unit to move to said extended position; a spring-biased positioning member mounted on said sliding unit and adapted to position the screw-retaining belt on said nose plate; a pivot pin mounted on said sliding unit so as to move together therewith in said longitudinal direction, and extending in a transverse direction relative to said longitudinal direction; and a spring-biased lifting member adapted to engage releasably a selected one of the engaging holes in the screw-retaining belt, pivoted to said pivot pin, and associated with said sliding unit in such a manner that said lifting member is moved in said longitudinal direction toward said rear end of said barrel unit and pivots about said pivot pin in a first direction so as to push the screw-retaining belt to move to a desired position, in which, a selected one of the screws on the screw-retaining belt is aligned with the driving shaft, when said sliding unit slides from said extended position to said retracted position against urging action of said urging member, and that said lifting member is moved in said longitudinal direction away from said rear end of said barrel unit and pivots about said pivot pin in a second direction opposite to said first direction to engage releasably an adjacent one of the engaging holes in the screw-retaining belt which is disposed adjacent to the selected one of the engaging holes in the screw-retaining belt when said sliding unit slides from said retracted position to said extended position by virtue of the urging action of said urging member.