GB1182380A - Sound Horn - Google Patents

Abstract

1,182,380. Horns. FORD MOTOR CO. Ltd. 18 July, 1968 [19 July, 1967], No. 34196/68. Heading G5J. In a vehicle horn, the path length taken by the sound waves in two adjacent spirally-shaped air passages 18, 42, Fig. 3, located in horn sections 16, 38 respectively (Fig. 1) is adjusted during assembly to suit the resonant frequency of a vibratory diaphragm 14. Sound-waves generated by the diaphragm 14 are reflected into the passage 18 by a wall 28. The air passages 18, 42 are separated by a flat plate 60 having located in it an aperture 70 (Fig. 3) to connect the passages. Immediately behind the passages, and attached to the plate 60, e.g. by rivets, is a V-shaped deflector 80, having one leg in each passage, the deflector functioning to direct sound waves from the passage 18 back down the passage 42 along the path shown in Fig. 3, from which they are further deflected into the trumpet 52 by a wall 50. The plate 60 is tightly held between the two sections 16, 38 of the horn, the position of the plate being determined before the rivets clamp the assembly together; thus the position of the aperture 70 and the deflector 80 can be selected. Extremities 96, 98 of the deflecting legs seal the air passages, and a screen 54 excludes dirt and water. All the deflecting walls are preferably at 45 degrees to the air passage axes, and each air-passage length is made substantially equal to one eighth of the sound wavelength. The V- shaped deflector 80 may be separate from the plate 60, and may be positioned by flat shelves or projections in the walls of the air passages.