GB187571A - Electrically operated signalling applicance or hooter - Google Patents

Abstract

187,571. Bosch Akt.-Ges., R. Oct. 17, 1921, [Convention date]. Diaphragm horns. - In electricallyoperated horns, for example, of the type in which the diaphragm 1 is directly connected with the armature 2 of an electromagnet 3, a second note of less intensity is obtained by connecting a choking coil 8 and a second signalling key in series with the electromagnet and in shunt with the usual key. This has the advantage over the similar use of a resistance that the full current strength is available for overcoming inertia &c. when starting up, the choking coil only becoming effective to reduce the current strength when the circuit is periodically interrupted at the contacts 4. The switching in or out of the coil 8 may be controlled automatically according to the speed of the vehicle or the number of revolutions of the engine. The invention is also applicable to horns in which the diaphragm is operated by means of an air pump set in motion by an electromagnet. Specification 21823/05, [Class 40, Electric telegraphs &c.], is referred to. The Specification as open to inspection under Sect. 91 (3) (a) also states that a single circuit in which the coil 8 may be switched in or out, may replace the two shunt circuits shown. This subject-matter does not appear in the Specification as accepted.