Automatic screwdriver with partially conductive screw-holder - performs DC continuity check in switching circuit completed by correct positioning of screw under tool bit

摘要

The retractable screwdriving tool (4) is driven (2) through a cylindrical sleeve (5) into the hollow shaft (6) of a guide (16) having a wedge-shaped upward extension (25) contg. a channel )(26), into which screws are fed singly through a flexible tube (3). The screw-holder is in two parts (14, 15) mounted on contact springs (10, 11) in an electrical circuit with a rleay (18) or semiconductor switch. A DC signal is supplied to the controller (1) only when a screw is correctly positioned. ADVANTAGE - End prod. quality is safeguarded by automatic monitoring of position of screw w.r.t. tool.