| 摘要 |
1,271,539. Loud-speaker diaphragms. FOSTER ELECTRIC CO. Ltd. 23 Dec., 1969 [22 Oct., 1969 (2)], No. 62585/69. Heading H4J A loud-speaker diaphragm has a foamed synthetic resin fused to one or both sides of a cloth. The cloth 4 (Fig. 4) has foamed resin 5 fused to it and may have a cloth insertion 7. A flat diaphragm (Fig. 2, not shown) has foamed resin fused on each side, except at the edge, which is corrugated. The cloth may be preimpregnated with a thermosetting resin (e.g. a phenolic urethane, polyester or epoxy resin). The foamed resin (e.g. a urethane, styrene, vinyl "A.B.S." or epoxy resin) may be cellular or collapsed. The cloth comprises yarns or rovings and may be of natural, synthetic or inorganic fibres and may be non-woven fabric. |
