| 摘要 |
PROBLEM TO BE SOLVED: To keep the state of power cut-off regardless of breakage at relays constituting a power cut-off device. SOLUTION: A first relay 30 equipped with one constantly-closed contact 31 and two constantly-opened first and second contacts 32 and 33, a second relay 40 equipped with constantly-opened first, second and third contacts 41, 42 and 43, and a vibration-sensitive switch 50 for opening the contacts, being responsive to vibrations, are provided. The second relay 40 is energized through the constantly-closed contact 31 and the vibration-sensitive switch 50, and electric power is supplied to a control device 8 through the constantly-opened second contact 33 of the first relay 30 and the constantly-opened third contact 43 of the second relay, and thereby an oil-feeding apparatus can be kept in the inoperative state until electric power is supplied again even through the relays 30 and 40 are broken. |
