| 摘要 |
<p>PURPOSE:To enable to obtain the waterproof construction of a ballast for electric-discharge lamp with a simple construction at low cost by a method wherein the protruding edge on the peripheral edge of a cover body is engaged with the side of an opening at the upper edge part of a case, and space between the protruding edge and the outside of the opening is extended toward the upper part from the neighboring site of the lower edge. CONSTITUTION:A protruding edge 5 to engage with the outside of an opening 3 is formed on the peripheral part of a conver body 4. The protruding edge 5 and the outside of the opening 3 approach at the lower edge part side 6, and space between the protruding edge 5 and the outside of the opening 3 is extended at the upper part to form a gap 7. Accordingly, when the device is installed in the outside, a waterdrop adhered to the lower edge part side 6 is apt to invade inside from a gap between the protruding edge 5 and the opening 3 according to a capillary phenomenon, while more invasion is stopped for further infiltration the gap 7.</p> |
