US1781974A - Gramophone, megaphone, or the like - Google Patents

Description

Nov. 18, 1930. A. H. BORGQVIST GRAMOPHONE, MEGAPHONE, OR. THE LIKE 2 Sheets-Shut 1 Filed May 31. 1928 FTgZ IIIIIIIIIIIIIIIII Nov. 18, 1930. A. H. soneov'ls'r GRAIOPHONE, HEGAPHONE; OR THE LIKE Filed May 31, 1928 2 Sheets-Sheet 2 I/l Ill/I: all/II II I II I! III llq'llllllllllllll lzn-l l lll lll ll m III/III!!!IIIIIIIIU'IIIIIIIIl/Ill Patented Nov. 18, 1930 UNITED STATES PATENT OFFICE GRAMOPI-IONE, MEGAPHONE, OR THE LIKE Application filed May 31, 1928, Serial No. 281,938, and. in Denmark September 6, 1927.

This invention relates to improvements in horns for gramophones or other devices for receiving or emitting music, speech and other sound vibrations, in order to obtain a great energy of the sound vibrations passing said horns or trumpets or rather to avoid any diminishing of the original sound energy and to absorb over-tones and other disturbing vibrations.

This can'certainly also be obtained by male ing the trumpetwalls very substantial, but if they are so, their vibrations will at the same time become less lively, and this can only be avoided by enlarging the measurements of the trumpet to such an extent that it would become practically inapplicable.

The purpose of my invention is to produce a horn possessing the advantages of the last vmentioned construction without having its great dimensions and substantial walls. This is effected by making the walls which are chiefly designed to reproduce the original vibrations of the source of sound not more substantial than is usually the case, but firstly to apply outside the trumpet some devices partaking of the vibrations of said walls,

secondly a heavy load as a resistance against too lively vibrations of said walls.

A still better result can be obtained by arranging some vibrating walls or other vibrating elements inside the horn. By using such co-vibrat-ing elements and those mentioned above, the single voice of the instrument will in some way be replaced by a chorus of several voices which are absolutely harmonious and nevertheless differ from them by their ability to reproduce the original vibrations in different clang-tints and therefore also are able to better reproduce the particularities of different instrumentsor voices.

By this construction it also becomes possible to absorb not only all superfluous overtones and to subdue the murmur of the higl speed gears of motors or the like, to avoid rumbling, rushing, snoring and crepitating sounds, but also at the same time to magnify the sound of the instruments in a surprising degree.

The accompanying drawing shows some devices as examples for practising my invention.

Fig. 1 represents one feature of a gramophone horn in a vertical section,

Fig. 2 the same in front-elevation on a lesser scale,

Fig. 3 and 4 two other features of gramophone horns, both in vertical sections.

The horn 1, preferably of a saxophonelike shape, is for instance by a flange 24, fastened to the bottom 2 of the disc-room 25 and by a ring shaped piece 3 connected with a plate or tongue l of metal, f. i. bronze or steel. This plate may be connected with one or several other plates?) and'with the sound board 6 by a bolt 7 or in any other way. Said metal plates 4 and 5 are suspended by the elements 3 and 7 only. Between each pair of metal plates 4 and 5 and between the last metal plate 5 and sound board 6 fastened at its sides and below to the case 11 of the machine, there are provideu spacing rings, elements or washers 8, 9 and between the sound board and the rear-wall of the case a spring 12 may be inserted in order to keep said sound board at a certain tension and thus to cause a resounding connection between the plate 6 and the outer wall 11 of the case.

As the upper and lower walls of the horn are very thin but comparatively broad, and thus their vibrations could become too lively, there is in the bow of the horn provided a weight 14: of any kind, preferably moulded of gypsum, concrete, or other plastic and later on hardening material. This weight will partake in the vibrations, thus reducing them to a strength which more appliablc to their purpose.

Another shape of the horn is shown in Fig. 3. Inside the mouthpiece of the horn there is inserted another but smaller horn 15 partaking in the vibrations of the outer born 1. Thus the room of the main-horn is dr'ided into three smaller rooms 16, 16, 16, and the area of vibrating elements essentially increased.

The construction of the apparatus dilfers also in other ways somewhat from that shown in Fig. 1, The metal plate 4 is in Fig. 3 directly connected with the outside of the horn 1, and the transfer 01 the vibration to the following metal plate 5 or plates, is effected by screw 8" with a nut 8"' connected with the'plate. In this case it is advisable to divide the sound board into two parts and connect the plate 5 by bolts with each 01. these parts. Also inthiscasc springs 1:2 are applied to hold said sound boards in tension.

' Instead of or together with the inner horn 5 there may be inserted inetal'tongues 23 ei g connected with t is rigid side walls of is l i Rally also ton ueshaped metal pieces 19, 19,

'- 1 ins de the neck or" the horn. The last one uspended at onc point i flonly, meanwhile re pieces 19 are fasten d to the side walls of the neck. 7 f

The two types of horns just specified are generally connected with the outer system of vibrating elements 4, 5, 6, and 11, as named in connection with Figs. 1 and 2.

What Iclaim' is: V

1. In sound amplifying apparatus,a'l1orn formed with a sharp goose-neck bend, in combination with a heavy mass disposed exteriorly of said hor'nbetween and engag- ,ing the opposing inner walls of said sharp bend thereof and serving to dampen the vibrations of .the walls of said horn.

2,111 sound amplifying apparatus, a hor formed with a sharp goose-neck bend, and

a sound board, in combination with a plural- V ity of resonance plates, one of said resone ance plates being mounted on said horn in spaced relation thereto to receive vibrations from the wall thereof, and another of said resonance plates being mounted on said sound board in spaced relation thereto, and an adjusting screw mounted in the latter resonance plate and adjustable therethrough to engage and exert varying degrees of pressure on the resonance plate mounted on the horn;

3.1n sound amplifying apparatus, a horn formed with a sharp goose-neck bend, re sounding, elements disposed exteriorly of said horn and mounted to receive vibrations direct from a wall of said horn, and a heavy mass disposed exterior of said horn and filling the interval between the opposedinner walls of said goose-neck bend thereof and serving to dampen the vibrations of the walls of said horn. V

4. In sound amplifying apparatus, a horn formed with a sharp goose-neck bend, a sound board, a plurality of resonance plate-s, one of said resonance plates being mounted on said horn in spaced relation thereto to receive Vibrations from the wall thereof, another of said resonance plates being mounted on said soundboard in spaced relation thereto, and an adjusting screw mounted in the latterresonance plate and adjustable therethrough to engage and exert varying io n 5 at one point 22 only and evenformed with a sharp goose-neck bend, 'asupport, a sounding board mounted at one end on said support, and a spring interposed between said support and the other end por 'tion'of said sounding board and forcing the latter away from said support, in combination with a plurality of resonance plates,

one of said resonance plates being mounted on said horn in spaced 1812131011 thereto to receive vibrations from 'a'wall thereof, and

another of said resonance plates being mounted on said sounding board in spaced relation thereto, and an adjusting screw mounted in the latter resonance plate and adjustable therethrough to engage and exert a varying degrees of pressure on the resonance plate mounted on the horn.

In testimony whereof, I have signed my name to this specification at Copenhagen this sixteenth day of May, 1928.

ALFRED HERSLEB Bone-lower,

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