| 摘要 |
PURPOSE:To improve detection accuracy of operational abnormality of a crossing rod by detecting horizontal balance condition and vertical balance condition of the crossing rod respectively. CONSTITUTION:In a lifting process of crossing rods 2A, 2B, when angle detecting means 17, 18 detect that angles of the crossing rods coincide with a predetermined angle, a sampling means (which consists of counters CTA, CTB and latches LA, LB) performs sampling of a current value or rotating speed of a motor at the time of detection detected by a motor current detecting means or a motor speed detecting means. A judge means (which consists of level detecting circuits 21, 22 and AND circuit) judges that this sampling value exists within a predetermined range or not, and when the sampling value is out of the predetermined range, the judge means judges that the operation of the crossing rods 2A, 2B is abnormal. |
