| 摘要 |
PURPOSE:To eliminate a generation of fatigue failure of arc-extinguishing plates through wind pressure by inserting folded parts provided in said arc- extinguishing plates into holes provided in an upper base and fastening said plates through welding and by inserting lower parts of said arc-extinguishing plates into grooves provided in a lower base and filling gaps formed in said grooves with elastic material. CONSTITUTION:Through holes are provided in an upper base 16a so as to be arranged in parallel with each other, arc-extinguishing plates 15 are inserted into said through holes respectively, folded parts 15a are put on the top surface of the upper base 16a, and the whole periphery of said folded parts 15a is welded and fastened to the upper base 16a. Also, grooves are provided in a lower base 16b at positions corresponding to said through holes provided in the upper base 16a so as to be arranged in parallel with each other, and lower parts of the arc-extinguishing plates 15 are inserted into said grooves. Gaps are formed in the grooves through said insertion, but an environmentally durable and elastic material is filled into said gaps to support the lower part side of said arc-extinguishing plates 15 elastically.
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