| 摘要 |
PURPOSE:To make the capacity of a capacitor comparatively small and consequently lengthen the service life of a power supply by a structure wherein a switch, which normally connects the capacitor to a power supply circuit but, when a manual operating member is released from an over-pressed operating range, connects the capacitor to a discharge circuit by changing- over, is provided. CONSTITUTION:A manual operating member 1 can be pressingly operated beyond the final end position of a safety valve 9 to an over-pressed operating range by deflecting a plate spring 22, which is fitted on a lever 7 at the side of an operating rod 6, after the safety valve 9 is open. The movable contact 28 of a switch 23 is connected to a capacitor 30, which flows discharge current so as to forcibly hold said safety valve 9 until the safety valve 9 is attracted in its open state due to the excitation of the solenoid 11 of an electromagnetic safety valve 8 by the electromotive force of a thermocouple 29. On the other hand, one contact of the two fixed contacts of the switch 23 is connected to a power supply circuit 31 and the other contact is connected to a discharge circuit 32, in which the solenoid 11 of the electromagnetic safety valve 8 and the thermocouple 29 are interposed. In the above-mentioned structure, the switch 23 normally connects the capacitor 30 to the power supply circuit 31 but actuates so as to connect the capacitor 30 to the discharge circuit 32 when the manual operating member 1 is released after being pressingly operated to the over-pressed operating range. |
