| 摘要 |
PROBLEM TO BE SOLVED: To attain cost reduction without drastically increasing the size of a device by providing a first contact means which includes a groove hole disposed adjacently to a contact area, and opening the hole at an opening position to the side of the first contact means facing opposite a contact area of a second contact means. SOLUTION: This device is provided with a groove hole 85 in a first contact means (stationary contact means) 50, a sidewall on the same side as a contact area 82 and a sidewall 85 on the same side as the contact area, and an arc development arear generated by the condition of opening, that is, an opening opened toward an arc extinguishing chamber. When an arc generates between final contacts of the stationary contact means 50 and a movable contact means 54, a current line in material of the means 50 is strengthened according to the depth of the groove hole on the same side as the contact area or according to the close condition of the final contact to an edge of the hole 84. Accordingly, through the cooperation between migration of arc head toward finger parts 68, 70 of the means 54 and ionization action generated by arcs, the arcs are stabilized in the vicinity of edge of sidewall 85 of the hole 84, and migration of arc into the arc extinguishing chamber occurs.
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