| 摘要 |
A method is disclosed of reshaping a sheet of resiliently deformable material impervious to fluid by conforming it to the cavity of a female mold and casting a flexible plastic foam into contact with said sheet material, whereby said material is integrated with the foam and forms a cover sheet therefor. A perforated elastic diaphragm is interposed, during the reshaping and foam casting process, between the cover sheet and surface of the mold cavity so that the cover sheet is in superimposed direct contact with the diaphragm throughout its area. The two are clamped to the periphery of the mold to form a seal thereat, and a differential pressure is applied across the cover sheet and diaphragm. The sheet is therefore deformed against the walls of the mold simultaneously with the diaphragm and is stretched evenly with the diaphragm in order to produce uniform thickness. If the cavity of the mold has a complicated configuration a diaphragm of varying thickness is used in order to ensure uniform stretching of the sheet. In simple molds, the diaphragm can be made to slide against the walls of the mold by using a lubricant which does not come in contact with the sheet being molded. The sheet and diaphragm together stretch uniformly because the diaphragm can slide against the walls of the cavity.
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