| 摘要 |
<p>1,127,813. Moving coil transducers. PHILIPS ELECTRONIC & ASSOCIATED INDUSTRIES Ltd. 13 July, 1966 [16 July, 1965], No. 31500/66. Heading H4J. In a microphone, loud-speaker or other moving coil transducer having a diaphragm provided with a throat portion effecting a connection with the moving coil, the diaphragm and throat portion are produced from a hardenable synthetic material without the application of pressure to contribute to the hardening. A cone diaphragm of non-uniform thickness may be provided. In manufacture of a loud-speaker, an unsupported moving coil 8 is wound on a reduced end 16 of a part 14 of a mandrel 13. A diaphragm mounting member 2 (e.g. of paper or rubber) is laid on a mandrel part 15. Hardenable epoxy resin or other synthetic material is sprayed on by nozzles 17, two side nozzles 18, 19 drawing off excess so that just the required rigidity at the connections 20, 21 is obtained. The mandrel 13 is heated by a member inserted in a recess 22. The assembly is preferably removed while the mandrel 13 is still warm. The nozzles 17, 18, 19 may be moved around the mandrel 13 or the mandrel may be moved around stationary nozzles. Several sets of nozzles may be provided. The synthetic material may be in powder form. Electrostatic spraying may be used. The coil 8 may be wound so that one turn engages the next, the insulation being heat softened to join adjacent turns. The diaphragm may be centred by a centring ring (4), Fig. 1 (not shown), the inner edge of the centring ring being embedded in the hardenable material. The transducer may be a microphone having a short throat (Fig. 3, not shown).</p> |
