Acoustic generator for motor vehicle horn - has diaphragm supporting coil in air gap with make and break contacts at centre

摘要

The acoustic generator has a cup-shaped steel shell (10) with a ring-shaped permanent magnet (11) housed inside. On this is supported a soft steel ring-shaped pole piece (12), leaving an annular air gap between its edge and the rim of the shell. An induction coil (13) is supported around a rim projecting inwards from a membrane (14) which is mounted on the flanged rim of the shell, so as to occupy the air gap. At its centre is a button carrying a contact (18) opposite a second contact (19) on a screw (16) passing upwards through the middle of the shell, to form a make and brake device (15) for the sound generation. The screw passes through an insulating bush (17) in the middle of the base of the shell. Alternative designs may include a plastics shell.