Adherence tool and its adherence tool Drive tool null which possess the non orbicular head which

摘要

PURPOSE: To prevent damage of head by forming a conical recess having non- circular circumference in head center of a screw, forming a centering pin top of a screw gun in a conoid corresponding to the recess of the screw, pushing the screw against a workpiece with the centering pin and rotating it. ;CONSTITUTION: A driving member 56 is actuated by pushing top end against workpieces 14, 16, and a screw gun drives a screw 20 through the driving member 56 axially connected to head 22 of the screw 20. A convex end 122 of the non-circular conoid is so slowly fit with the recess 40 of the non-circular conoid that it does not give a friction force while driving the screw. Furthermore, a tubular extension part 108 is engaged with washer 26 of the screw 20 after a socket 110 is central-axially engaged to the head 22 for limiting central-axial movement of the socket 110 to the head 22. The centering pin 120 makes centering of the socket 110 and head of the screw. By this manner, damages of fastener and workpiece can be prevented.;COPYRIGHT: (C)1993,JPO