US1169134A - Sound-box for talking-machines. - Google Patents

Description

Ubll SS FA WILIBURN N. DENNISON, OE MERCHANTVILLE, NEW JERSEY, ASSIG'NOR TO VICTOR TALKING MACHINE COMPANY,.A CORPORATION 0F NEW JERSEY.

SOUND-Box ron 'rAILKINGr-ivneosiiuiis."v

To all whom 'it may concern Be it known that I, WILBURN N. DENNL son, a citizen of the United States, and a resident of the borough of Merchantville,

county of Camden, and State of New Jersey,

box to improve the reproduction of sound therefrom; to provide a sound box in which the diaphragm will be normally held fiexed by an initial pressure when not in operation to counterbalance the pressure which is ordinarily exerted on the diaphragm by the lateral pressure on the stylus due to the propelling action of therecoid upon one side of the stylus, in carrying the sound box. across the face of the record.; to make it possible to assemble commercially large' numbers of sound boxes with diaph'ragrns held between gaskets with substantially the saine pressure; and to provide other iniprovements as will appear hereinafter.

In the accompanying drawings, Figure 1 is a front elevation of a sound box constructed in accordance with this invention; Fig. 2 a longitudinal vertical section of the same; Fig. 3 a bottom plan view of the same with a, part shown in dotted lines for clearness; Figs. l and 5 are longitudinal sectional views of details of the same; Fig. 6 is a fragmentary transverse section of a detail of the saine; Fig. 7 a fragmentary side elevation partly in section of a portion of the same; Fig. v8 a horizontal section on line 8, 8 of Fig. 2; and Fig. San lenlarged longitudinal section of a portion of the same.

Referring to the drawings, one embodi-v ment of this invention comprises an outer casing l, a diaphragm 2, gaskets 3 and 4:' for holding the diaphragm in position, an annular back plate 5 which is. provided with Specification of Letters Iatent.'

Patented aan'. es, ieie.

. Appiicaaon'iiied May 27, 1909'. -serial No. 498,697.

means for securing a gasket in place, and also with means for connecting the sound box .to the usualv sound conducting tube, a locking .ring for retaining the back. plate in position in the outer casing, and a stylus bar 7 mounted to oscillate upon the casing, the front of the casing being recessed as at to permit of the free oscillation of the ar. i

The locking ring 6 has a substantially fiat inner surface, and the back plate 5 diers from the ordinary` construction in that itis provided upon its outer face with a circular marginal rib 5 curved in cross section and Ahaving a convex outer side against which the fiat inner surface `of the locking ring 6 engages throughout only a very narrow region which is practically only a circular line. This construction makes it easy in practice to insure a substantially uniform pressure of the locking ring against the back plate'5 without having to provide carefully fitted coperating surfaces between the ring and the back plate and aHords a simple arrangement whereby the seating of the back plate in the outer casing 1 may be effected with certainty.

The outer casing l of the sound box coinprises a substantially cylindrical rim portion 8, having an inwardly extending lange 9, integral therewith upon the front side thereof, forming a circular front wall having a centrally arranged opening 10. On the interior face of the wall 9, and spaced from the internal periphery of the outer casing is an annular rib or projection 11 concentric with the wall 9. This rib forms with the internal surface of the rim 8 and the internal surface of the front wall of the casing, an annular groove 12, substantiallyv rectangular in cross section but with rounded.

bottoni corners, the walls of whichy form a seat for the outer gasket 3.

' The rim 8 of the casing lis counterbored from its rear end forming a cylindrical recess coaxial therewith to receive the back plate 5, and forming a rearwardly facing annular stop shoulder 13 to limit the inward movement'of the back plate. The back plate 5 forms the rear wall of the sound box casingi and is substantially parallel to and coaxial with the front wall 9 of the casing.

The back plate 5 is preferably madeof the same material as the outer casing and is provided atits periphery with an inwardly projecting cylindrical Harige 14, which abuts against the internal stop shoulder 13 of the rim 8 and limits the inward movement of the back plate.` This back plate 1s also provided, with an annular rib or projection 15 y on its inner face similar to and coaxial with 16 similar in shape and equal in size to the opposite groover12, and the walls of which forni a seat for the inner gasket 4.

For increasing the eiliciency of the sound box the back plate is provided with-a rib projecting inwardly toward the diaphragm, and may be formed as a cylindrical annular bushing 17 of .metal or other suita'ble material threaded into or otherwise adjustably secured in the centrally disposed circular' opening 18 of the back place, the inner portion of the bushing projecting inwardly from the adjacent internal surface of the back plate and forms a rib or projectionwl terminating in Very close proximity to lthe diaphragm, the space between the end of the rj v said rib 17 and the diaphragm being substantially as small as is practical without causing actual contact between the said rib and the diaphragm when the sound box is in operation. The bushing is provided in its outer end. with apertures 17 adapted to receive a spanner wrench whereby the bushing 17 may be adjusted toward or awav from the diaphragm. If preferred this bushing 17 and the-annular projection 17v may be made integral with the back plate, and in any case forms a continuous `projection bordering or surrounding the opening in the back plate and the internal or lcylindrical surfacego'f` the bushing 17 forms-the internal wall df'the inner end of the sound conducting opening 18 of the sound box casing.

AThis construction of the back plate and bushing leaves an annular recess or chamber 18 inthe inner rear face of the casing concentric with the outlet so that the passage of air orsound waves into the outlet or'passage from the interior portionof the casing surrounding the outlet and in the rear'- ot the diaphragm, is restricted by the inwardly extending bushing or rib 17 at the margin of the said outlet or'passage, and when the diaphragm vibrates toward the outlet, part'v of.

the air in the sound box will be partially trapped by the diaphragm .in this recess or chamber 18 and compressed to a greater extent than would `he the case if the passage of air through the outlet were not thus re-4 stricted. This compressing of the air inthe recess or chamber 18 may also serye to cushion the dlaphragm and some of the air thus- 'compressed will be sharply forced Vthrough `through the outlet to the sound' conveying tube or opening is restricted, the central circular portion of the diaphragm bounded by the said annular projection is free toset up vibrations directly in a. straight li-ne through the opening in the back ofthe sound box to the sound conveying tube and the character of the sound waves may thus be largelydetermined by the action of this central portion of the diaphragm as well as by the action of the air ejected into the said outlet from the recess or chamber 18.- This construction gives a reproduction having an unusually clear and definite quality.

, F or attaching the sound box to the usual sound conveying tube 20, the back plate fof the box is provided with a coaxial rearwardlyprojecting tubular extension 19 conimunicating with the sound conducting opening 18 and adapted to receive the end of the sound conducting tube 20. The internal diameter of this tubular extension is preferably about tlie same diameter as the external diameter of the bushing 17 in the back plate,

in the rim 8 of the outer casing of the sound box, a locking ring 6, screw threaded on 'its external periphery, as shown at 23, is'

threaded into the rear ofthe outer casing, the outer casing'beingprovided with internal screw threads 24 to receive the external threads of the ring. The locking ring 6 is provided with Spanner holes 25 to receive a spanner wrench for rotating the ring to tighten the same against the back plate 5, and to force the back plate against its seat.

The two gaskets 3 and 4, for supporting j the diaphragm, are preferably made of'rubber, o r o-ther'yielding material, and are each i in the form of a solid ring having a body portlon substantially rectangular in cross section but having its corners slightly rounded as atf26. Each of these gaskets is provided Vupon one of its side faces with" an annular rib orcontinuous projection 27 coaxial therewith which tapers outwardly in cross section from the body of the gasket and terminates in a narrow flat face parallel to the ilat sides of the gasket. The sides or 5 peripheral edges of the rib are preferably concave and curved in cross section and tangential to the adjacent sideof the body ot the gasket. c

The gaskets are positioned upon their y seats in the casing as heretofore described,

,20 inserted within the outer casing, with its flange 14 abutting' against the shoulder 18 of the outer casing, the diaphragm will be held yieldingly in position between and by the ribs of the gaskets. The flat outside face of each gasket resting in the seat, forms a lirm support for the gasket and prevents its displacement and the gasket is preferably oblong in cross section and of greater width than thickness, as shown in Fig. 6, to form a relatively broad supporting surface for the gasket.

The thickness of the gaskets 3 and 4l and the depth of the recesses or grooves 12 and 16, in the casing 1 and backing plate 6 re spectively, is made so that when the back plate 5 is screwed down hard upon the internal stop shoulder 13 of the casing, the diaphragm will be held between the ribs of the gaskets 3 and 4 with the requisite and de- 4o sired pressure so that with uniform gasket-s and with a number of sound boxes provided with groot/'es of the same depth, and the shoulder 13 in the same position with respect to the grooves 12 and 16, a large number of sound boxes can be assembled substantially absolutely alike b y merely pressing the back plate 5 up firmly against its shoulder by the locking ring 6. v

The diaphragm -or vibratory member for compressing sound waves is preferably made of mica o-r any other suitable resilient material of the usual circula-r form. The diaphragm is arranged coaXially with the -casing and is somewhat less in diameter than the internal dia-meter of the outer casing so that the periphery of the diaphragm is spaced from the casing.

The stylus bar or diaphragm actuating device, comprises an arm 28, an oii'set or laterally extending portion 29, and a stylus holder 30. The stylus holder 30 is'provided with the usual stylus socket vitor holding a stylus 31 and with a thumb screw 32 for retaining the stylus in position. The arm :28 of lthe stylus bar is tubular and is connected at its inner end to the'central portion of the diaphragm by any suitable means. The inner end of this arm spreterably substantially circular in cross section and extendsoutwardly substantially perpendicular to the diaphragm, and then curves to meet the main portion 34 of the arm whichv extends in a direction substantially parallel to the diaphragm. This main portion S4 of thev arm flares outwardly from its junction with the inner end of the arm and is substantially elliptical in cross section, the longer axis of a cross section of the main portion l-l being substantially at right angles to the diaphragm, when the diaphragm is flat. so

The oil-set or laterally projecting portion 29 of the stylus bar connects the stylus holder 30 and the arm 2S of the bar, and Jis yieldingly connected to a supporting member 35, which is rigidly attached to the 85. sound box casing, as will be described hereinafter.

The supporting member comprisesa main or body portion consisting of two substantially rectangular flat rigid plates 37 90 and 38,.and the major or central portion of a thin flat plate 89 of tempered spring steel or other resilient or yielding material which is clamped between the rigid plates 37 and 3S by means of rivets 40 extending through 95 all the plates and securing them permanently together. The yielding plate 39 is provided with spaced yielding arms 41 and a2 integral therewith which project foryvardly from its main portion and from the front edges of the plates 37 and 38, as shown partly in dotted outline in `llig. 3.

The outer casing A1 is provided upon its under surface with 'a boss or liXed support 43 having an outer plane surface 44 sub- .10o stantially rectangular in shape against which is rigidly secured the supporting member 35 by :means of screws l5 passing through the supporting member and into the boss. The plane surface of the boss is of ll@ substantially the same shape and dimensions as the inner surface of the supporting member and is recessed to-receive the heads of the rivets of the supporting member. The supporting member thus bears against the H5 boss throughout substantially the entire eX- tent of the supporting member, thus insur- 'ing avery rigid connection between the supporting member and the sound box, and obviating the slight vibration which might arise if the body or main portion of the supporting member projected to any great eX- tent` beyond the edge of theboss.

' vThe off-set portion'? of the stylus bauis composed of lthree thicknesses of platesll, :W5

a7 and e8. .Ot these the two plates 46 and 47 are or thesame size and form and each has a pair of laterally progecting arms 46 and 47 extending in opposite directions respectively from the stylus har, Between the la@ free ends of these arms .are secured the free ends of the projecting resilient arms 41 and 42 of the steel plate 39, by means of rivets 40', thus forming spaced yielding resilient supports for the stylus bar. These two plates 46 and 47 are spaced apart by the third plate 48 whichis of the rsame thickness as the spring arms. The supporting member 35 is recessed centrally on its front edge as at 49 to receive the inwardly projecting central portion 49 of theoff-set portion 290i? the stylus bar, and the front surfaceof the .stylus holder is rigidly secured by riveting or otherwise, in van aperture extending through the three plates, 46, 47 and 48 in the inwardly projecting portion 49 of the off-set portion of the stylus bar.

The stylus bar is preferably positioned upon the sound box so that the axis of oscillation of the bar and the longitudinal axis of the stylus socket are substantially in the plane of the diaphragm, 'when the diaH phragm is in a flat condition, and the longitudinal axis of the stylussocket is preferably arranged radially of the sound box. The space between the offset portion of the stylus bar and the adjacent edges of the supporting member 35, is preferably onlysufficiently wide to permit of the free oscillation of the stylus bar and the bar is thus restrained to oscillate upon a substantially fixed axis.

vFor connecting Vthe outer end of the arm Q8 of the stylus bar with the off-set portion Q9 of the bar, the front portion of the off-set portion 29 is provided with an aperture 50 extending through the plates 46, 47 and 48 into which tightly fits the elliptical outer end of the arm. A comparatively short transversely elliptical tube or bushing 51 of soft annealed brass or other suitable material having its external dimensions substantially the same as the corresponding internal diameter of the outer end of the arm 28, and having its inner end slightly tapered, is

then forced tightly into the end of the arm,

slightly expanding the arm and compressing the tube and rigidly binding the end of the varm in position in the aperture 50;

Vhile the outer end of the arm 28 and the aperture 50 in the off-set portion Q9 are shown as elliptical. other shapes mightbe employed without departing from the spirit of this invention. The bushingv 51 may also be of difierentshape from that illustrated,

so long as it corresponds to the shapev of the internal diameter of the outer end of the,

arm 2S, so that when forced into said arm,

it effects a rigid binding of the said arm supporting the sound box the bar will be slightly turned or displaced on its axis from its normal position, slightly flexing or applying aninitial tension to the spaced spring arms supporting the stylus bar, and the upper end of the stylus bar will co11se p1e11tl y exert a slight initial pressure rearwardly against the central portion of the Adiaphragm, springing or flexing or dishing the diaphragm which is preferably made of mica or other resilient material, slightly in ay direction toward the outlet in the back plate of the'sound box casing, as shown exaggerated in Fig. 2.

When the sound box, thus constructed. is supported by its stylus upon a sound record in a siate of rest or in an inoperative position. the diaphragm will remain in substantially the same flexed condition as when the sound box is not supported by the stylus, but being perhaps slightly more flexed, due to the. weight of the sound box on the free end of the stylus, which vhas a slight tendency to turn the stylus bar about its axis and to increase correspomlingly the tension upon the spaced spring arms supporting the bar and the pressure of the upper end of the stylus bar against;J the diaphragm. lVhen,

however, the sound box is in operation and 1s being propelled. as is customary, across.

a record by the engagement of its stylus with the record. a pressure sufficient to cause the travel of the sound box will lbe exerted upon the stylus bar in the direction of the travel of the sound box, as indicated by the arrow in Fig. 2, tending to turn the innerend of the stylus bar outwardly and to relieve the initial inward pressure upon the diaphragm.

The initial pressure or tension upon the diaphragm is adjusted to malte it substanw tially balance the pressure exerted upon the side of the stylus during the operation of the sound box. to propel the sound box across the record, so that act-ing through the stylus bar, the turning moment of one of these pressures will counterbalance the other and the diaphragm will be under substantially no tension or pressure due to the propulsion of the sound box. when in operation, across the record, and will be substantially free, as far as these forces are'conce1-ned, to assume its natural form, which in this case would be thatof a flat disk. By

lll

this construction a symmetrical action of the applied also to other forms than the one illustrated, for instance the sound box might be of the type known as pneumatic, in which a current of air or other fluid is forced through the sound box and the sound Waves are impressed upon the fluid current by a. vibratory flat, flexible resilient valve or other vibratory means actuated by a stylus bar. In this case the valve or other vibratory means would then take the place of the diaphragm of the sound box illustrated, and when the term diaphragm is used in the claims it is intended to cover any such valve or vibratory means equivalent to a diaphragm for performing thesame function of impressing sound Waves.

Although only one form of this invention has been illustrated and described, the invention is not limited to the exact construction set forth, as various changes might be made in'applying this invention, Without departing from the spirit of the invention or the scope of the appended claims.

` Having thus fully described my invention, I claim and desire to protect by Letters Patent of the United States:

l. A stylus bar having a member provided with an aperture, a tubular arm tting in said aperture, and means Within said tubular arm for holding the same in position.

2. A stylus bar having a member provided with an aperture, a tubular arm fitting in said aperture and tubular means iitted tightly Within said tubular arm for holding the same in position.

3. A stylus bar having a member provided with an elliptical aperture, an arm ellipitical in transverse section litting tightly in said aperture and an elli )tical tubular bushing fitted tightly into sai arm to hold said arm .and said member rigidly' together.

4. A stylus bar having a member provided with an aperture, a tubular arm fitted tightly in said member' and a bushing fitted tightly in said arm to hold said arm and said member rigidly together, said arm tapering aivay from said member and saidbushing having its inner end tapered.

copies af una patent may ae @baisee fm A gasket for supporting a diaphragm in a sound box comprising a yielding member substantially rectangular in transverse section and having an annular rib projecting therefrom.

6. A gasket for supporting a diaphragm in a sound box, `comprising a solid yielding member substantially rectangular in transverse section and having an annular rib -projecting therefrom.

7. A gasket for supporting a diaphragm in a sound box comprising a yielding ring lsubstantially rectangular and oblong in transverse section and an annular jecting from one side thereof.

8. A gasket for supporting a diaphragm in a sound box comprising a yielding ring substantially rectangular in transverse section and having rounded corners, and an rib proannular rib projecting from one side thereoi 9. In a sound box, the combination with a diaphragm, of an annular yielding gasket having an annular rib projecting therefrom, said rib having a flattenedface in contact with the diaphragm.

10. In a sound box, the combination of a casing, a bach plate having a circular rib of curved cross section extending from the back thereof, and a nut, threaded in said casing and seated upon said rib.

1l. ln a sound box, the combination with a. substantially cylindrical casing, of a substantially circular back plate telescoping in said casing, and an annular member engaging said casing and contacting with said back plate only in a substantially circular line, and clamping said casing and said back plate in relatively xed relation.

l2. ln a sound box, the combination with a substantially .cylindrical easing, of a substantially circular plate telescoping in said casing, and annular means carried by and rotatable coaxiallj7 with respect to said casing and engaging said plate only in a subA stantially circular line and clamping said plate in a fixed position with respect to said casing.

ln Witness whereof l have hereunto set my hand this 26th day of May, A.' l). 1909.

W'LBUBN N. DENNSN.

Witnesses:

FRANK B. ltronLnToN, Jr., Hanni' E. YV. KENNEDY.

tivo cents each, 'by sreasng the Gommssioner of Patents, Washington, n. e.

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