摘要 |
A plastics cover plate 6 is assembled to a plastics shell 1, e.g. to form the main portion of a moving coil electro-acoustic transducer of which the shell contains the magnet assembly 2, 3, 4, the plate 6 having a number - six in one case - of inwardly-extending studs 7. The assembly involves placing the cover plate 6 in position when the magnet assembly 2, 3, 4 is in the shell 1, and then applying ultrasonic vibrations and pressure to the cover plate. This causes the studs to collapse around the magnet assembly 2, 3, 4 and the inside of the shell 1, thus effectively locating the magnet assembly in the shell. There is also an energy concentrator 11 on the shell 1, and this, in addition to the function of concentrating the applied energy acts as a seal, since it also collapses to secure the shell 1 and the cover 6 together. Although the method has been described as applied to the assembly of a particular transducer, it should be noted that it is not so limited. <IMAGE> |