| 摘要 |
<p>The electromagnetic make-break device such as a horn comprises a membrane (1) at the entrance to a labyrinth chamber (2) and carrying a vibrating armature (3) cooperating with a coil (13). The coil circuit includes two normally closed dome contacts (7, 9) mounted respectively on one end of a lower leaf spring (6) and on upper contact breaker bridge (8). An axle (4) secured centrally of the diaphragm projects through the bridge (8) for abutting the leaf spring (6) via an insulating head. The bridge (8) and spring (6) are secured together and in a housing (10) at their other ends, with the bridge (8) electrically isolated from the securing bolt (11) and spring (6) by insulating washers (14, 16) and on insulating sleeve (15). Energising the coil (13) constracts the armature (3) and thus the diaphragm (1) carrying the axle (4) to abut the spring (6) and brake the contacts thus allowing the contacts (7, 9) to reclose, and so on. The positions of the bridge (8) and thus the spring (6) are adjustable to cater for contact wear by adjusting the bolt (11) and a further bolt (12) securing the opposite end of the bridge (8).</p> |
