Abstract: An electric horn (1) has a coil bobbin (4) in a casing (2). A fixed iron core (3) is fixed in a hole (4f) in the coil bobbin (4) and is magnetized to define an exciting coil (C). A moving iron core (10) is at the center of a diaphragm (9) at the open end of the casing (2) and faces the fixed iron core (3). The moving iron core (10) is displaced relative to the fixed iron core (3) by a power supply of the exciting coil (C); thus beeping an alarm. The moving iron core (10) has an end face toward the fixed iron core (3) that strides over a reference position (N) within the amplitude (W) of the moving iron core (10). The end portion on the moving iron core (10) side of the wound portion (4e) of the exciting coil (C) is the reference position (N).

Abstract: An electric horn (1) has a coil bobbin (4) in a casing (2). A fixed iron core (3) is fixed in a hole (4f) in the coil bobbin (4) and is magnetized to define an exciting coil (C). A moving iron core (10) is at the center of a diaphragm (9) at the open end of the casing (2) and faces the fixed iron core (3). The moving iron core (10) is displaced relative to the fixed iron core (3) by a power supply of the exciting coil (C); thus beeping an alarm. The moving iron core (10) has an end face toward the fixed iron core (3) that strides over a reference position (N) within the amplitude (W) of the moving iron core (10). The end portion on the moving iron core (10) side of the wound portion (4e) of the exciting coil (C) is the reference position (N).

Abstract: A drainage structure of a volute horn including a resonating device has a cover and a base which form a volute sound path. A relatively long and narrow drainage passageway is formed in the portion of the resonating device where water collects for draining water from the sound path such that the sound pressure in the sound path remains constant. As a result, the integrity of the horn sound is maintained.

Abstract: A volute horn is assembled by integrally attaching a horn body to a resonating device forming a volute sound path. The horn body includes a vibration generating unit for vibrating diaphragm to create a sound, and a cover facing the outer surface of the diaphragm provided so as to block an opening in a housing. The resonating device is formed of a frame and a base. The frame is formed so that the bottom of the sound path is open, and the base is integrally secured to the bottom of the frame so as to block the sound path in an airtight manner. A first opening is formed in the cover, and a second opening is formed in the base. Sound produced by vibrating the diaphragm is transmitted through the first and second openings and into the volute sound path. The first opening communicates with the second opening in an airtight manner.