| 摘要 |
<p>A length of foil sheet is fitted with parallel transverse support struts for stretching it when spread out, in the provision for roofing over a surface, esp. a swimming pool. The struts are elastic, and are fixable in a stretched position forming a supporting arch for the length of foil, at least across its length. They may be housed in an elongated pocket in the foil, while a much wider pocket at the side serves to accommodate a heat-insulating layer. This enables the length of sheeting to be stretched in an arch shape above the area being covered.</p> |
