| 摘要 |
<p>A door, or core panel for a door, is made of a lightweight set and hardened material based on cement and/or gypsum. Lightweight characteristics can be achieved by having large voids in the panel (Fig 2), but are more preferably achieved by (a) suitable choice of lightweight, natural or synthetic, particulate or fibrous, fillers, additives and aggregates or (b) the intentional incorporation of a multiplicity of small air voids, as a set and hardened air-entrained or aerated material or (c) as both (a) and (b) together. The panel can also be configured with strengthened portions to accept hinge connections, door-closers, and like stress-applying fitments (Figs 5 and 6), and the faces and edges of the panel, as a core, can be suitably clad with wood (ply or veneer) decorative paper or metal sheets (Figs 3 and 4).</p> |
