Impact horn
The Aufschlaghorn or plate horn is a signal horn design based on the principle of Wagner's hammer , which is constructed similar to an electric bell .
functionality
It essentially consists of an electromagnet with an armature held by a spring . The armature strikes the magnetic core as soon as an electrical voltage is applied, whereby an interrupter is actuated, so that the armature snaps back and is attracted again when the current flows again. A capacitor for spark quenching prevents electrical erosion between the contacts of the interrupter and is also used for radio interference suppression . The breaker does not apply when the device is operated with alternating current . The fundamental frequency depends on the dimensions of the moving parts. Sometimes an adjustment screw allows the volume and tone to be changed . Spring-loaded mounting brackets are intended to prevent the vibrations from being transmitted to the housing as structure-borne noise instead of as air- borne noise to the environment.
The audible tones that make up the sharp character of the signal device are overtones of the fundamental frequency, which are usually in the range of 2000–3000 Hz. Apart from a round vibration membrane that serves as a resonator , there is no need to amplify the sound. This design became the most widely used car horn before the Second World War .
fanfare
In combination with a column of air in a horn , which is coiled in a spiral shape in compact models, the impact horn becomes an electromagnetic fanfare , like a horn loudspeaker limited to one frequency, so to speak . These fanfares are more sonorous and less penetrating than the impact horn without a funnel, because the fundamental frequency is amplified instead of the overtones . The excitation oscillation and the oscillating air column (ie the dimensions of the funnel) must be matched to one another in order to achieve a satisfactory level of efficiency . In contrast to the Martin's trumpet , which is operated with compressed air , this type of trumpet responds faster, with mostly less sound.
literature
- Brockhaus - The Encyclopedia. Volume 10: Mr. - Eat. 20th, revised and updated edition. Brockhaus, Leipzig et al. 1997, ISBN 3-7653-3110-4 , p. 335.
Web links
Individual evidence
- ↑ http://www.welkomopmijnwebsite.nl/members/grundbuch/TG%20elekt.%20Ausrustung+Armaturen_photo.html , p. 78
- ↑ Olaf von Fersen (ed.): A century of automobile technology. Passenger cars. VDI-Verlag, Düsseldorf 1987, ISBN 3-18-400620-4 , p. 322.