Patent ID: 7963194
Filing Date: 2011-06-21
Classification: B23P

Abstract:
1. A screw fastener comprising: a screwdriver that includes a sleeve having an absorption hole configured to absorb a top surface of a screw, a bit housed in the absorption hole and having a tip engageable with a recess of the screw, and a rotation unit configured to rotate the bit with the sleeve; a movement unit configured to move the screwdriver between a container configured to accommodate the screw and a work; a controller configured to control operations of the screwdriver and the movement unit so as to pick up the screw from the container and to fix a part onto the work with the screw; and a positional shift detector configured to detect a positional shift on a plane between a center axis of the screw perpendicular to the plane and a center axis of the bit perpendicular to the plane, wherein the controller controls a movement of the movement unit so as to reduce the positional shift, based on a detection result of the positional shift detector, and wherein the positional shift detector includes: a pressure detector configured to detect a pressure in the absorption hole; and a groove configured to connect the absorption hole to and disconnect the absorption hole from air external to the sleeve according to a rotational position of the sleeve.