| 摘要 |
PROBLEM TO BE SOLVED: To automatically determine a predicted screw tightening time (reference time) as a reference for determining whether screw tightening is well completed or not merely by performing a tightening test for screws of specified quantity without using a stopwatch. SOLUTION: Steps S1-S8 are performed until the quantity m of tested screws reaches a predetermined quantity ms (S9, S10). The TIM1 finally obtained is set and stored as a reference value Re (step S1). The reference value Re is used as a reference for determining whether tightening is good or not in a normal screw tightening operation performed after a screw tightening test. When the predicted time TIM1 is set short, the reference time becomes equal to the predicted time TIM1. Therefore, the predicted time TIM1 may be set to the maximum value of the settable time or a time longer than the screw tightening time for the screws requiring the longest tightening time used for a motor-driven screwdriver. COPYRIGHT: (C)2009,JPO&INPIT
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