AVVISATORE ACUSTICO CON CUSTODIA DEFORMABILE PLASTICAMENTE NEL SENSO PARALLELO ALL'ASSE DI REGOLAZIONE PER LA TARATURA DEL TRAFERRO NEI TIPI ELETTROMAGNETICI E DELLA PRESSIONE DI ESERCIZIO NEI TIPI ELETTROPNEUMATICI

摘要

A vehicular warning device comprises a sound generator of electromagnetic or electropneumatic type with two components, one of them including a diaphragm, that are relatively axially movable in a generally cylindrical housing supporting both components. The peripheral housing wall has a corrugated zone forming at least one annular bulge which can be compressed between a pair of clamping jaws during tests following assembly. Such compression, with permanent deformation of the housing wall, reduces the axial height of the housing so as to narrow the air gap between a membrane-supported electromagnetic armature and a confronting core member or to intensify the pressure exerted by the diaphragm upon an entrance end of an air channel normally blocked by that membrane.