| 摘要 |
PURPOSE:To enable engaging condition to be securely confirmed by urging an article set once to the forcibly engaging condition in the opposite direction with a force weaker than the engaging one to confirm that the article is kept engaging even against the reverse urging force. CONSTITUTION:When after closing a lid by a lid opening and closing device, a change-over valve 66 is changed over to again operatively extend a cylinder 64, i.e. in the direction of opening the lid, a change-over valve 67 is also changed over to pass pressurized oil from a pump to a circuit B through a fixed orifice 65 for extending the cylinder 64. Here, the lid is securely closed and the internal pressure in the circuit B is increased unless the lid is rotated by small pressure urging the lid in the direction of opening. Then a pressure switch 72 is turned on so that securely closed condition is confirmed. On the other hand when the lid is rotated by the opening operation due to the small pressure, the internal pressure in the circuit B is not increased. Since the pressure switch 72 is left turned off, the incompletely closed condition is confirmed and a pot repeats again the closing operation or generates an alarm. |
