| 摘要 |
PURPOSE:To prevent the development of thin wall part and broken part in a rib at molding and, at the same time, realize larger mechanical strengths such as rigidity and the like and also obtain favorable external appearance. CONSTITUTION:The body concerned is a hollow double walled structure having one wall 3 and the other wall 4, both of which are blow-molded integrally and are opposite to each other. Concretely, the one wall 3 and the other wall 4 are integrally bonded together by two ribs, which are made to be parallel to and apart from each other. Each rib is formed by integrating a recessed rib 5, which is formed by recessing some part of the one wall 3, with a solid rib 6, which is formed between the apex surface of the recessed rib 5 and the other wall 4, resulting in forming minute unevenness over the whole surface of the outer surface of the outer wall 4. Thus, the mechanical streigths such as rigidity and the like become larger. And neither sinkmark nor warpage develops and favorable external appearance is obtained. |
