US1722007A - Sound-amplifying device for sound reproducing and recording instruments - Google Patents

Description

July 23, 1929. s, ODONNELL 1,72%007 souND AMPLIFYING DEVICE FOR SOUND REPRODUCING AND RECORDING INSTRUMENTS Filed March 19, 1926 3 Sheets-Sheet 1 y 23, 1929- P. s. ODONNELL 1,722,007

SOUND AMPLIFYING DEVICE FOR SOUND REPRODUCING AND RECORDING INSTRUMENTS Filed March 19. 1926 3 Sheets-Sheet 2 y 23, 1929- I P. s ODONNELL 1,722,007

SOUND AMPLIFYING DEVICE FOR SOUND REPRODUCING AND RECORDING INSTRUMENTS Filed March 19, 1926 3 Sheets-Sheet 5 16 A; K mmwf-n o {a i [2 8 l y ma Patented July 23, 1929.

v uN irao-fS TES 1,722,007 PATENT" oF FicE. f

' rA'rRIoK 'SH'AUGHNESSY ODONNELL, or LONDON, ENGLAND.

sounn ararnirymo DEVICE FOR scum) nrirnonucme AND RECORDING insrnumnn'rs.

H Application filed March 19, 1926, Serial No. 96,008, and in Great Britain May 11, 1925.

This invention relates to, and has for its object the provision of improvements in, sound reproducing apparatus.

The invention consists broadly in the arrangemcnt according to which the vibrations of the sound to be reproduced are adapted to set up sympatheticvibrations in tuned gongs.

One embodiment of the invention is illustrated in the accompanying drawings and the 0 Same will now be described, it being unden' stood that the particular construction and arrangement illustrated are susceptible of various modifications without departing from the scope of the invention as defined in the appended claims.

In these drawings Figure 1 is a side elevation of a loud speaker (particularly for use in connection with wireless apparatus) in accordance with the invention, the casing thereof and certain other parts being shown in section.

Figure 2 is an end elevation of the same looking from the left of Figure 1.

' Figure 3 is a similar end elevation of all those parts to the right of line X-X of Figure 1, certain of the parts being shown in chain dotted lines.

Figure 4 is a side elevation of a detail. Referring to the drawings the loud speaker therein illustrated comprises an electromagnet 1 the armature 2 of which is adapted to vibrate in accordance with the vibrations of the sound to be reproduced. The vibrations of thiselectromagnet are adapted to be transa mitted' to a diaphragm 3 of conical shell formation through the medium of a transmission device which. comprises two diamonds 4 and 5 which are insirrple contact with one another and which are in rigid relationship respectively with said armature 2 and said diaphragm i j Thus the diaphragm 3 is rigidly and-coaxia-lly' mounted 'to a rod 6 extending" outwardly fromits apex, and this rod 5 carriesat its remote extremity the diamond 5.

The armature'2 carries a cup 7 which con tains the other diamond 4. The rod'G/is rebracketlfisothat the axis of said rodpasses througlithe diamond 4 and the middle of the t armatiirefQZ. A' gspring 6 is provided for with: respectto saidjsleeve in s ch. aiwgyit at; thediamond 5 is presseddown-upon thetliainonde.

i The vibrations 03E the armature 2. are adapted to take place in a sense at right angles to the rod 6 and thus the diamonds 1 and 5 tend to rub one another in sense at right angles to the direction of the pressure between them. In practice the regularity of form of the two diamonds results in an engagement between them such that the rod 6 together with the diaphragm 3 vibrates transversely of its axis. Sound waves are therefore emitted from saiddiaphragni. I

The bracket 9 and the electromagnet 1 are both supported from a common base 10 which consists of a glass disc and is suported. in spaced relation from the back 11 of the loud speaker casing by means of four supporting feet 12 spaced around its circumferential periphery. The electromagnet is mounted. to this base in the neighbourhood of its centre and'the bracket 9 is made in the form of asleeve 8.

bridging member carrying the aforesaid The loud speaker casing is of cylindrical t formation the back 11 thereof thus being disc shape. mounted therewithin at spaced intervals around the circumferential wall of said casing a number of tuned gongs 13 each of which represents a definite musical note. These gongs are of spiral type and are located as The front thereof is open and has shown in radial planes with respect to the cylindrical casing and with their mounting points nearest the open end of the casing. They are mounted to an annular base 14 extendingaround the inner periphery of the casing as shown. The gongs are partly isolated from one another by means of baffle plates 15- also arranged in radial planes.

-- These bafile plates come between the. outer halves only ofeach pair of the .gongs (i. e. the halves nearest the openend ofthe casing) and are formed so that they becamenarrower 'as theyappro'ach the. centre of thecasingjnear to which theyv terminate. .They: also are mounted to'said base 15 andat their inner ciprocably mounted in a sleeve 8 carried by'a ends carry anannulus 15.. l 1

Rigidly and c'oaxially' mountedv upon an extension of the sleeve 8 and-betweenthe dia- 1 phra auxiliary diaphragx'ns are of, progressively varying diametersand are arranged in spaced relation to one another with the largest near- ,est the diaphragm 3 and the smallest nearest the bracket 9. 7

Between the cup 7 and the armature 2 and inrigid relation with both is-a lass disc 17.

Extending between the disc s ape base 10 and the annular base 14 are four'wooden rods 18. These rods are mounted to said base 10 by means of blocks 18 cemented to, and overhanging the circumferential periphery .pf, said base, and arebolted to the base 14 as shown.

In operation the vibrations are transmitted as described by means of the diamond contact transmission device from the armature 2 to the diaphragm' 3. Sound waves are thus emitted from said diaphragm and pass out through the open end of the casing past the gongs 13. The purity of the sound thus produced is enhanced on account of the said transmision device and also as a result of the gon s 13. the transmission through the contactmg diamonds probably has the effect of making the vibrations of the diaphragm 3 more nearly simple harmonic vibrations than are the vibrations of the armature 2 but this is not'certain. The gongs operate to break down echoes and false vibrations and to enhance the true notes. Each gong responds to its own proper note and tends to swamp false notes. The auxiliary diaphragms 16 and the disc 17 have the effect of further increasing the mellowness and purity of the tone pro- .duced. The scientific explanation of this is not however quite clear. The connection between the base 10 and the base 14 by means of the rods 18 has the eflect of increasing the sensitiven'ess of the gongs. Very slightvibrations are transmittedfrom said base 10 to said base 14 and thus the gongs themselves are maintained in a slightly tremulous state in which they are more readily susceptible of sympathetic response to their proper notes than when they are in a state 'of rest.

Describing now certain constructional details of the device, the electromagnet 1 consists of a core .1 havingenergisable pole pieces 1" arranged one each side of the'armature 2 and adapted alternately to attract and repel the same. The armature 2 is mounted to a somewhat resilient bridging piece 2 one end of which is rigidly mounted to the base 1 to which the core 1 is mounted and the otherend of which is mounted to said base in such away as to be adjustable with respect thereto in a vertical sense. Such adjustment is adapted to be efl'ected by means'of an adjusting column passing through a hole in said base 10. Thebase 1? is secured to the base 10 by means of a suitable cement.

T e cup 7 is made in one unit with the disc '17 and with a suitable screw 19 by which said.

unit is screwed to said armature 2. A washer 20 say ofebonite is interposed between said screw 19 and the armature 2.

' clamped e is stamped into a pleated form. In the par-- ticular construction illustrated the former method is adopted and the frame members of the diaphragm 3 are shown in Fig. 2 at 3". In this figure the bafiie plates 15 are shown superimposed over the radial frame members 3". This is purely fortuitous and should not cause confusion. The diaphragm 3 is provided with a boss 3 by which it is screwed onto the end of the rod 6 and said diaphragm v is also supported from the periphery by means of strings 3 secured to the inner periphery of the casing. The diaphragms 16 are formed with bosses 16. whereby they are spaced apart.

The four supporting feet 12 are provided with grooves as shown in which the edge of thebase 10 fits. These grooves are provided with rubber or like pads 12 above and below the edge of said base.

No claim is made in this specification to the I construction of the connection between the 95 loud speaker diaphragm and the actuating member thereof and comprising two hard jewels respectively connected to the diaphragm and said member and arranged in simple contact with one another to transmit. the vibrations of said member to said diaphragm, as such connection is described and claimed in my copending ap lication for Letters Patent of the United tates for Sound producing apparatus, filed March 19, 1926, Serial No. 96,010.- V

v No claim is made in this specification to a. loud speaker comprising asound emitting diaphragm having an unclamped edge and a dampin diaphragm also having an un- 1 e located behind said sound emitas ,this is described; and.

lication for Lettates for sound tin diaphragm cla lmed in my copending ap ters Patent of the United 7 reproducing apparatus, filed March 19, 1926, 1

Serial No. 96,009.

What I. claim and desire to secure by Letters Patent is 1. Aloud speaker comprising a dia hragm for producing thesound waves, a puralityof tuned gongs mounted in the path which said sound waves are adapted to takevand baflie plates located between adjacent pairs of said gongs. i

1 2. 'A 16 d speaker comprising a casing hav- 1 ing a sound wave exit, a sound wave producing diaphragm located within said casing, a plurality of tuned gongs of the spiral type mounted within said casing, said gong be disposed adjacent said sound wave exit an 1 in planes approximately radial with respect to the approximate axis of saidsound wave exit and battle plates located between adjacent pairs of said gongs in such a way as only partially to isolate said pairs of gongs.

3. Aloud speaker comprising a cylindrical casing having one end open to provide a sound wave exit, a sound wave producing diaphragm located within said casing, a plurality of tuned gongs of the spiral type mounted around the inner periphery of said casing in planes approximately radial with respect to the axis-thereof and baflle plates located between adjacent pairs of said gongs in such a way as only partially to isolate said pairs of Q 4. A loud speaker according to claim 3 wherein said bafile plates decrease in breadth as they approach said axis of the casing.

5. Aloud speaker comprising a casing having' a sound wave exit, a separate sound wave producing diaphragm located within said casing and a plurality of tuned gongs rigidly mounted within said casing adjacent said sound wave exit and between said diaphragm and said wave exit. 1

6. Aloud speaker comprising'a cylindrical casing having one end open to provide a sound wave exit, a separate sound wave producing diaphragm located within said casing and a plurality of tuned gongs of. the spiral type mounted around the inner periphery of said casing and in a sense approximately radially of the axis thereof, so as to be between said diaphragm and said sound wave exit. I In witness whereof I atfix my si ature.

' PATRICK SHAUGHNESSY 'DONNELL.

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