| 摘要 |
A method of detecting failure to tighten screws against works (3) includes steps of detecting every screw tightening operation against the work (3) after start of a screw tightening step, counting the number of times of the screw tightening operations detected in the previous step, detecting the completion of the screw tightening step, and comparing a counted value at the time of the completion of the screw tightening step with a predetermined value, thereby informing of a result of comparison. A device for carrying out the method includes a current relay (17) responsive to a large load current during the tightening operation of an electric screwdriver (11) in a screw tightening step, a presettable counter (12) for counting the number of operations of the current relay (17), photoelectric switches (4, 5) detecting completion of the screw tightening step for the work (3), and an alarming device (23). |
