| 摘要 |
PROBLEM TO BE SOLVED: To manufacture easily a case by forming enclosed joints jointly with the bottom or the cover by extrusion. SOLUTION: An airtight joint 7 defining two enclosed areas on the periphery of a partitioned chamber 5 in cooperation with the bottom 2 when the case 1 is in a closed state, is arranged in the inside of the cover 3 facing the bottom 2. The joint 7 has two flexible lips mutually parallel, preferably of the same size and projecting axially. When the case 1 is in a closed state, the lips of the joint 7 are closed to the bottom in the periphery of the partitioned chamber 5, in more detail, the lips are flatly closed and contacted under pressure to the upper edge of a wall 6, and the compression of the lips occur in the joint of the case 1. Thus, two enclosed areas extending mutually parallel in the periphery of the partitioned chamber 5 are formed. The joint 7 can be extruded jointly with the bottom and cover that are molded from a synthetic material such as a polypropylene by the displacement of a rotary molding machine or a core.
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