US1780788A - Sound-reproducing mechanism for radios - Google Patents

Description

A. M. KENNEDY SOUND REPRODUCING MECHANISM FOR RADIOS Nov. 4, 1930.

2 sheds-sheet '1 Filed Aug. s, 1929 INVENTOR M BY ATTOR'NFY Nov. 4, 1930. A. M. KENNEDY SOUND REPRODUCING MECHANISM FOR RADIOS Filed Aug. 3, 1929 2 Sheets-Sheet 2 ATTORNEY Patented Nov. 4, 1930 UNITED STATES AUBREY M. KENNEDY, or Losnnennns, CALIFORNIA SOUND-BEPRODUCING MECHANISM FOR RADIIOS Application filed August 3, 1929. Serial No. 388,270.

The object of the present invention is to provide means for use in radio broadcasting and receiving for reproducing sound either in the sending or the receiving of the sound 6 waves. Specifically the invention relates to apparatus comprising magnetically actuated tuned diaphragms incorporated in either radio broadcasting devices or in loud speakers for reproduction of broadcast sounds, the

diaphragms being so related to the actuating magnets that they may be selectively actuated in accordance with the character of the sound waves.

The invention will be described with reference to the accompanying drawings, in which- Figure 1 is a plan view, of an embodiment of the invention, and

Figure 2 is a sectional elevation of the same Figure 3 is a modified form of the apparatus;

Figure 4: is a schematic view in elevation of an embodiment of the invention in conjunction with a microphone for broadcasting;

Figure 5 is a view in sectional elevation of a further modification, and

Figure 6 is a plan view of the same.

In the present practice of radio broadcasting and receiving, a diaphragm is employed in both the microphone and loud speaker which is selected for its average efliciency in the translation of the magnetic electric impulse into vibrations or sound waves. The same diaphragm is used for a symphony orchestra as for a violin solo, and that used for a choir is the same as used for a single voice. It is impossible to construct one diaphragm which will be suited to all musical or other sound vibrations. If a diaphragm is so constructed as to be particularly adapted for the sending or reproduction of vibrations of high pitch, that diaphragm will not ordinarily be adapted for the best reproduction of low pitch vibrations, and there are other conditions which restrict a diaphragm of a given construction.

Referring to Figures 1 and 2 of the drawings, it will be seen that 1 is a casing in which are mounted seven diaphragms indicated by the letters A to G inclusive. Above each diaphragmthe casing is formed with an outlet I indicated at 2, and the outlet may communicate with a horn or other amplifying member. Within the casing and adapted for registry with each one of the seven diaphragms is the magneticreproducing'assembly 3 which may be of usual construction. The reproducing assembly, in the said embodiment, is fixed, whereas casing 1 is movable, longitudinally, so that the diaphragms may selectively be brought into register with the reproducing assembly. Each diaphragm may be tuned to a note in the standard musical scale. Assuming the device to be constructed as a loud speaker and a violin solo is to be reproduced,

the diaphragm tuned to that particular vibration is used, forexample diaphragm F. The casing is moved to a point where the reproducing assembly will actuate that diaphragm. Assuming that the'device is employed as a broadcasting assembly, the action will be the same. :F or example, announcement'may be madeby the ,broadcasterthat a violin solo is to be broadcast and the direction given to use diaphragm F, which will be the diaphragm used by the broadcaster, and-those listening in may accommodate their loud speakers to diaphragm F. r

Tuning of the diaphragms may be accom-- plished by various methods, as for'example, difference in thicknesses of the diaphragms,

ditferencesin materials used,,differences in sizes, etc. 7

;-I-n. the structure of Figure -3 the .dia-

phragms are carried by a slidable frame member 4 and the reproducing assembly'is fixed within a casing 5. The casing is pro vided with aligned apertures for the passage of the slidable frame 4 so that the dia phragms may be selectively placed in register with the reproducing assembly.

In theconstruction shown in Figure 4, the

diaphragms are carried by a rotatable frame member 6 movable about an axis 7. -At 8 I have shown, diagrammatically, a microphone, the microphone being so related to frame member 6 that the diaphragms may be successively brought into operative register with the microphone for actuation by the i magnetic elements thereof. Any suitable means may be employed for maintaining the diaphragms' in juxtaposition to the microphone magnetic elements, as will be understood by those skilled in the art. In Figures 5 and 6 I have shown a casing 9, a magnetic assembly 10, and means for removably supporting any one ofv a plurality oafdiaphragms, one of the diaphragms being I shown at 11. In the front wall of the casing 10 an aperture12 is providedthrough which the I I I I diaphragms may selectively be passed, Ar-

ranged in annular formation within casing I a I V, 9 are a plurality of lower leaf springs '13 supported by annular member 14 ofthe cas- 15 ing and supported by the top wall 9 of the V casing are a plurality of leaf springs 13*,

arranged in annularformation. Each diaphragm maybe provided with a handle- 'by means of which:the diaphragm maybe passed through aperture 12 and between the a two'sets of springs so .as to be held firmly in position. Springs 13 may be stronger than vsprings"13 and above springs 13 may be placed a rigid metallic ring 21- in register 25 with set screws 22, by means. of which the ring may be moved downwardly so asto carry thediaphragm toward the pole pieces 23 of'the'magnetic assembly 10. By reversely rotating the I thumb-screws the strongest springs 13 raise thediaphragmv An equivalent'adjustment may be provided for the member 4 illustrated in Figure 3. Havingdescribed my invention, what I I claim and desire tosecure by'Letters Patent I I is as follows a *zflvlni radio reproducing mechanism, in combination with a magnetic assembly of a support, diaphragm holding 'means' in said II support and a'diaphragm provided with a 40 carrier, the diaphragm being so related to the holding means that itvmay be moved into the support and'gripped by the holding means for coaction with the magnetic assembly, and i V V removed-therefrom by withdrawal in the h planeof its face; a r

7 2. Afdevice constructed in accordance with I claim 1, in combiriationwith means for actllating the diaphragm toward and from the I magnetic assembly in a direction transverse U to the plane of the diaphragm face. 7 r g In testimony'whereof, I havesign'ed my name to this specification. 7 AUBREY M. KENNEDY. A

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