Apparatus for inserting and removing screws

An apparatus for driving self-tapping screws, with screw heads, in and out of a work piece along a screwing axis, the apparatus comprising:

• a screwing unit and a screw feeding unit relatively movable toward and away from one another along the screwing axis;
• releasable screw retaining means positioned on the screwing axis;
• means in said screw feeding unit for feeding screws from a magazine along a supply path in a supply direction to the retaining means;
• a screwing tool member for positively rotationally driving the screws, and means for mounting said screwing tool member on the screwing unit, said screwing tool member engaging successive screw heads with an axial movement relative to the screw heads from an initial position in an axial advance direction of the screws;
• a driving shaft connected to the screwing tools member and adapted for connection to a motor driving means for rotationally driving said self-tapping screws in and out of the work piece;
• and,
• rotary drive means operable to rotationally align the screwing tool member with respect to the successive screw heads independently of the drive means, the rotary drive means being arranged between the screwing tool member and the driving shaft, the screwing tool member being axially movable relative to the driving shaft from the initial position in a direction opposite to the axial advance direction into a retracted position, wherein upon axial movement of the screwing tool member towards the driving shaft, the screwing tool member is simultaneously forced by the rotary drive means into a rotating movement relative to the driving shaft, the rotating movement being a fraction of a revolution of the screwing tool member.