US1353479A - Sound-box for sound recording and reproducing machines - Google Patents

Description

E. R. JOHNSON. SOUND BOX FOR SOUND RECORPINQ AND REPRODUCING MACHINES R m FM m W P a 3 a 5 E 3 N ATTORNEYS t. H. JOHNSON. soum) BOX FOR souma RECORDING AND REPRODUCING MACHINES.

' APPLICATION FILED NOV. I2, 19!]. 1,35 3,479. PatentedSept. 21,1920.

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2329.6; q Egg nvvslv TOR ATTORNEYS WITNESS E. R. JOHNSON. SOUND BOX FOR SOUND RECORDING AND REPRODUCING MACHINES.

APPLICATION FILED NOV. I2, 1917. I 1,353,479. PatentedSept. 21, 1920.

3 SHEETS-SHEET 3. I

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0 r IIIIIIIIIQ UNITED STATES.

PATENT OFFICE.

ELDRIPGE' R. JOHNSON, F MERION, PENNSYLVANIA, ASSIGNOR TO VICTOR TALKING MACHINE COMPANY, .A CORPORATION OF NEW JERSEY.

SOUND-BOX FOR SOUND RECORDING AND REPBOD' UCING MACHINES.

Application filed November 12, 1917. Serial No. 201,627.

I T 0 all whom it may concern:

of Pennsylvania, have invented certain new and useful Improvements in Sound-Boxes for Sound Becordingand Reproducing Machines, of which the following is a specification.

The object of this inventionis to produce a sound box which is very sensitive, and is equallyresp'onsive to the fine rapid, complex sound vibrations, and to the simple, less frequent or slower vibrations, whereby a true, accurate record of sound vibrations may be produced or reproduced by the use thereof.

Further objects of my invention will appear in the specification and claims below.

Referring now' to the drawings forming a part of this specification and in' which the same reference letters are used to designate .the same parts throughout the various views,

Figure 1 ma front elevational view of a sound box embodying my invention; Fig. 2 is a side elevation of the same; Fig. 3 is a bottom plan view of the same; Fig. 4: is a fragmentary sectional view taken on the line 4--4= of Fig. 3; Fig. 5 is a fragmentar rear View of the lower portion of the soun box;

Fig. 6 is a perspective view of one form of the spring member of the stylus bar mounting; Fig. '7 is a fragmentary sectional view showing the way in which the spring member and the stylus bar may be connected together; Fig. 8 is a front elevational View of a modified form of my invention; Fig. 9 is a side elevational viewof the same; Fig. 10 is a bottom plan view of the same; Fig. 11 is a fragmentary sectional View taken on the line 11-11 of Fig. 10; Fig. 12 is a fragmentary rear view of the lower portion'of the sound box showing the mounting for the stylus bar; Fig. 18 is a detail fragmentary view showing the manner of attaching the spring members to the stylus bar; Fig.14 is a plan view of one of the spring members used in the modification shown'in Figs. 8 to line 18-18 of Fig. 17.

In Figs. 1 to 7 is illustrated the preferred form or embodiment of my invention and therefore the description of the invention will first be directed particularly thereto.

The sound box'casing comprises a front part or portionl and aback part or portion 2 between which portions the diaphragm 3 is mounted. Thesound box back 2- is provided with a rearwardly extending portion 2and with an aperture 4 extending through said back portion 2, and through the projecting portion 2'. The interior of the opening 4: is provided with a pin 5 by meansof which the sound box is secured and positioned with respect to the'sound, conduit (not shown). The diaphragm 3 within the sound box casing is preferably held in position by two elastic gaskets 6--6, but this invention is not to be construed as limited to therparticular form of mounting for the. diaphragm. Thus, another form of gasket is shownin the second and fourth modifications and embodiments'of my invention (see Figs. 11 and 18) in which the gasket is shown as a channeled elastic or resilient an nular member 6, which yieldingly engages opposite sides of the diaphragm 3.- Any other suitable form of mounting for the diaphragm may, however, be employed in carrying out the invention of this application.

The stylus bar 7 consists of a pivoted, os-

Patented Sept. 21, 1920.

cillatory member, the upper portion 8 of -7. The upper portion 8 of the stylus bar and the stylus holding portion-10 preferably extend in substantially parallel directions. They are offset with respect to each other, and are rigidly connected together by the rigid-web or connection 9.

Adjacent the top of the stylus holding portion 10 of the stylus bar 7 are preferablv provided a pair of oppositely dlsposed alined members forming a crossbar 11, on which the stylus bar, as a whole substantially vibrates, and to which are attached the spring members for applying the desired amount of tension to the stylus bar.

The outer ends of the cross bar 11 are respectively provided with flat surfaces 11'- 11' having kerfs or V-shaped channels 12 extending longitudinally thereof. Preferably that portion of the cross bar 11 which is adjacent the stylus carrying portion 10 is substantially circular in cross-section, and the ends thereof are preferably substantially semi-circular in cross-section, providing flat surfaces 11-11 which lie in a plane slightly above and parallel to a diameter of the said circular portion of the cross bar and normal to the axis of the portion 10 of the stylus bar 7, and the bottoms of the V- shaped grooves are in alinement wlth the axis of the cylindrical portions of the cross bar 11.

The stylus holding portion 10 of the stylus bar 7 is preferably provided with a socket or recess 13 for the receptlon of the stylus 13' and is further provided with a set or binding screw 14 communicating with said recess or socket 13, for the purpose of tightly binding or holding the stylus 13' within the socket and thus rigidly uniting the stylus with the stylus bar.

' V-shaped channels 12 in the flattened sur-- Aportion of the edge of the front member 1 of the casing is preferably flattened, and a plate or base 15 is rigidly secured thereto, as by brazing or soldering, said plate 15 being provided with a pair of spaced pivot members 16-16, the top edges of which are V-shaped to form knife edges adapted to be seated within the kerfs or faces l1'11' of the cross bar 11. V

The cylindrical portions of the cross bar on opposite sides of the stylus holding portion 10 are preferably respectively provided with a spring member 17, such as is shown on an enlarged scale in Figs. 6 and 7. Said spring members 17 preferably consist of spring steel, and are preferably provided with straight ends 18 having transverse holes or openings 19 for the reception of screws 20 by means -of which said ends thereof are rigidly secured to .the cylindrical portions of the cross bar 11. Adjacent said straight ends 18 are curved portions 21, substantially arc-shaped and at the opposite ends of said arc-shaped portions 21, said spring members 17 may be each provided with a second substantially straight portion 22 which may extend substantially radially from the center of said arc-shaped portion 21. The ends or portions 22 of said spring members 17 are preferably provided with longitudinal slots 23 for the reception of adjusting or tensioning screws 24, pass- 7 ing therethrough and threaded into a suit able opening therefor in the lugs 25 projecting from opposite edges of the plate 15; The spring members 17 on opposite sides of the stylus holding portion 10 are preferably oppositely or reversely disposed with respect to each other as clearly illustrated in the drawings, the screws 24 at the ends 22 thereof being onopposite sides of the axis of oscillation of the stylus bar 7.

As constructed and arranged as above set forth, these spring members 17 perform the double function of holding the kerfs or channels 12 of the trunnions or cross bars 11 in firm engagement with the knife edges at the tops of the pivot members 16,. and of imposing a suitable and adjustable tension on the stylus bar. Then the spring members 17, 17' are rigidly secured to the cross bars or trunnions 11 in the manner indicated in Fig. 7, and the adjusting screws 24, pass ing through the slots 23, are screwed into the plate 15 as above described, the tension of the springs is so applied as to firmly hold the knife edges of the support 16 in engagement with the kerfs 12 of the trunnions 11, and their resiliency permits the stylus bar to vibrate against the tension of the springs. As all of the members of the mounting of the stylus bar are small, and as it is desirable to mount the axis of the stylus bar relatively closely to the casing, the plate 15 may be provided with an opening 26, opposite the head of the screw 20, to prevent any contact or engagement of the head of the screw 20 with the plate 15. The back plate 2 maybe provided with a suitable recess 27 within which the screw 24 may enter. To hold thescrews 24 in any adjusted position, lock nuts 28' may be provided as clearly shown in Fig. 4. In order that the upper portion 8 of the stylus bar may be located relatively near the diaphragm, the rim of the front member 1 of the'sound box casing may be provided with a suitable groove or channel 29, to provide clearance between the upper end of the stylus bar and the sound box casing.

bar will both be increased. Asthe adjusting screws are withdrawn, the said pressure and tens on are diminished.

Referring to Fig. 7, the substantially cylindrical portion of the cross bar 11 is shown in cross-section and the spring member 17 as attached thereto. This figure also illustrates particularly the fact that the spring member which,-for convenience may be termed a circular spring, may be secured to the cylindrical portion of the cross bar at any desired circumferential point thereon dependent upon the purposes to 105 From the above it will be seen that the I ment to the cross which the sound box may be adapted to be put. Generally speaking, a cross bar, circular in cross-section,

sired point, and the flat end of the spring may be firmly secured thereto at that point.

Thus, cordance with this invention, the exact point at which a given spring should be secured to the cross bar to obtain the best reproduc- 'tion of sound, may be readily ascertained by experiment and having fixed that point on a particular cross bar, other stylus bars may be readily provided with similar springs attached thereto at the same relative point. If, for any reason, it be desirable to replace a given spring so mounted on a cylindrical cross bar with another spring difiering from the first in length, resiliency 'or other particular, such new spring may be readily secured to a cylindrical cross bar in another position circumferentially thereof and best adapted to. such new spring without substantially changing the stylus bar as awhole, except as to the providing of a new hole therein for the attachment of the new spring. 1

The portions of the cross bar, embodied in the various modifications in which this invention is. shown as embodied, and to which the springs are attached, has been termed substantially cylindrical because it might be, and generally, is desirable to provide it with a limited flat surface 11" at the point where a spring member 17 is attached thereto for the purpose of securing a firm tightclamping of. the spring between the head of the screw 20 and the cross bar. These flattened surfaces 11", however, are limited and, to obtain the full advantages of the cylindrical shape of the cross bar, should be formed after the point at which thescrew 20 should be attached has been determined upon. The providing of the cylindrieal portions of the cross bar with these limited flattened surfaces would not, however, substantially interfere with the attachbars of other spring members, like or similar to the spring members 17, at other points thereon and the providing of new flattened surfaces upon which such new springs may be securely fastened.

The oppositely disposed spring members 17 operate to hold the trunnion or cross bar 11 in engagement with the knife edges without exerting any tendency to displace the stylus bar transversely upon its axis upon the pivotal knife edges during the vibration of the stylus bar. The tendency of one spring to do this is balanced by thetension of the other. Moreover, the curved portions 21 of the springs normally possess centers about which substantially all distensions or contractions will occur, and these centers of the'curved portions 21 of the springs are may be readily provided with a tapped radial hole at any de-' in making up soun'd boxes in -action of the stylus bar so that as the stylus bar vibrates, the spring members 17 will substantially coil and uncoil about centers which are for practical purposes coincident with the axis of-oscillation of the stylus bar.

v Ina sound box arranged and constructed as above described, the stylus bar is held upon its pivot members with a definite amount of spring pressurewhich remains substantially the same throughout all the functionings of the stylus bar. It is also tobe noted that during the operation of the sound box, that is to say, the vibration of the stylus bar, the extension and contraction of the respective spring members are opposite with respect to each other, that is to' say, while one is being distended by the swing of the stylus bar in one direction, the other is being retracted. A further feature of the invention resides in the fact that the spring action takes place substantially entirelywithin the curved portions 21 of the springs. These portions contract and distend without any substantial tendency to move, push or slide the free end 22 of the spring transversely with respect to-the screw 24. The

motion due to the vibration of the stylus bar is substantially all absorbed in the curved portions 21 of the springs.

By making the ends 18 of the spring members straight at the point where they are attached to thecross bar 11, the curved portions 21 are kept at all times out of actual contact or engagement with the cross bar '11 except at the points of their attachment thereto, and any rattle .or other undesirable noise due, to the striking or engagement of the flexible portion 21 of thevsprings against the crossbar is thereby obviated.

-It may here be noted'that while the aopenings 23 in the ends of the spring members 17 are shown as elongated, such. elongation is not for the purpose of permitting the end 22 to slide transversely with respect to the screw 24 during the operation of the device, but is for the ready assembly of the parts together, irrespective of any slight variations in form or lack of alinement of the individual parts when assembled. As above stated, the portion 22 is stationary with respect to the screw 24 in so far as any vibrations are concerned. The elongated openings 23 also permit the free ends 22 to be adjusted in different positions without producing any binding or cramping between the springs and the screws 24.

In the embodiment of my invention, as illustrated in Figs. 8 to 14, inclusive, the spring member 17' is shown as substantially helical in shape and the middle portion 18 is preferably flattened and is attached to the trunnion or cross bar 11 by a screw 20. That portion of the cross bar 11 to which this spring is so attached, may be and preferably is provided with a flattened surface 11", because in this embodiment of the invention, the point of attachment of the spring to the cross bar is preferably invariable in the middle of the spring, and at an invariable point with respect to the cross 'bar. The outer ends 22' of the spring 17, are preferably provided with slots 23 for the reception of suitable adjusting screws 24, threaded into lugs 25 on the face plate 15. Between the flattened portions 18' at the middle of the springs and the ends 22 there-' of, these springs are arc-shaped in side elevation on either side of said middle por tions and provide curved portions 21 similar to the curved portion 21 of the spring members 17 shown in Figs. 6 and 7. In this form of the invention, each spring member 17 therefore, substantially encircles the substantially circular portion of the cross bar or trunnion 11 and cooperating with the adjusting screws 24 tends to hold the stylus bar firmly on its knife edge and to apply the desired tension to the stylus bar under the influence of sound vibration.

In the modification illustrated in Figs. 15 and 16 the construction of the mounting for the stylus bar is substantially identical to that illustrated in Figs. 1 to 7, except that the cross bar or trunnion30 is mounted to oscillate on the adjustable alined pivot pins or screws 31 threaded through spaced lugs or projections 16 from the base plate 15, said pivot pins 31 having conical ends firmly seated in conical recesses provided therefor in the ends of the cross bar 30. Preferably,

- these pivot pins or screws 31 are provided with check nuts 32 to firmly hold them in their adjusted positions. In this embodiment of my invention, the spring members 17 operate to apply the desired tension on the stylus bar but they are not called upon or required to apply a tension on the cross bars for the purpose of holding the stylus bar upon knife edge bearings. The pivot pins 31 provide the means for retaining the stylus bar in a fixed predetermined position with respect to the sound box proper.

The spring members 17 as illustrated in Figs. 15 and 16 are not required to apply tension to hold the stylus bar upon its mountings, but they operate in other respects in the same manner that the spring members 17 do in the form shown in Figs. 1 to 7. By the contraction and expansion of the curved portions 21, they substantially absorb the vibrations of the stylus bar and apply the desired tension thereto. When so mounted upon rigid pivot pins 31, a single spring member 17 might in some instances be employed, provided the free end 22 were rigidy supported with respect to the sound box casing. To do this, an additional check nut or binding nut may be provided on the adjusting screw 24 to clamp the free end 22- of the spring firmly between the head of the screw 24 and the nut 33.

In the modification shown in Figs. 17 and 18, the open-sided-bearingsshown and illus trated in connection with Figs. 8 to 14, inclusive, are replaced by non-yielding bearings consisting of the alined pivot screws 31, as in the form shown in Figs. 15 and 16, and if desired, the free ends 22 of the spring members 17' may also be clamped between the heads of the adjusting screw 24 and a nut 33 in the same manner as that illustrated in Fig. 16.

In this modification also, the springs 17' are employed to impose the necessary tension upon the stylus bar, but they are not required to exert a pressure on the crossbar for the purpose of holding the cross bar. on knife edge bearings, as the pivotal bearing screws 31 support the stylus bar in a fixed predetermined position.

'Briefiy, the spring members or springs 17 shown in the modification illustrated in Figs. 15 and 16, are like the spring members shown in the modification illustrated in Figs. 1 to 7, and the structure diffeis in the replacing of the knife ed e or other opensided bearings shown in Figs. 1 to 7 with unyielding pivotal bearings. Similarly, the spring members 17 of the modification shown in Figs. 17 and 18 are like the spring members shown in Figs. 8 to '14 and the construction merely involves the replacing of the knife edge or other open-sided bear- 100' ings with pivot pins or other unyielding bearings. In the structure shown in Figs.

15 to '18, the spring members operate to tension the stylus bar in the same manner that the spring members shown in Figs. 1 to 14 impose a tension to the stylus bar and the operation of the spring members shown in all the figures, under the influence of the. vibration of the diaphragm, is alike. The motion of the styus bar is modified by the tension of the circularly curved or arcshaped portions of the spring members as these portions expand and contract somewhat in the manner that the hairspring of a balance wheel of a watch coils and uncoils, but, of course, to a much more limited extent.

It is of course to be understood that the invention of this application may be embodied in slightly different constructions over those illustrated in the drawings of this application, and the same is'not to be construed as limited to the exact form or proportions illustrated, for various changes .maybe made without departing from the spirit and scope of this invention.

This application is a continuation in part of a rlor application filed by me May 1,

ent positions to vary the tension 'tively fixed positions whereby said sty I claim and desire to protect by Letters Patent of the United States:

tively curved oppositely around the saidpivotal axis of the stylus bar.

2. In'a sound box, the combination of a casing, a stylus bar, a bearing on said casing for said stylus bar, springs attached to said stylus bar and each having a portion curved around the axis of oscillation of said stylus bar, and means to fixedl holdthe free ends of said springs in di erent positions to vary and through said springs to hold said stylus bar on said bearing.

3; In a sound box, the combination of a casing, a stylus bar, a'bearing on said casbar, a palr of sprmgs ating for said stylus tached to said stylus bar and each having a portion spirally curved around the axis of oscillation of said stylus bar in opposite directions respectively, and means to fixedly hold the free ends of said springsin differof said springs and said stylus'bar, and through said springs to hold said stylus bar on said bearing.

4. In asound box,

bearings in which said stylus bar is mounted, a pair of oppositely disposed spiral springs each being attached to said stylus bar and being curved around the axis of oscillation of said stylus bar in opposite directions respectively, means disposed springs secured to said stylus bar and each comprlsinga. portion substantially spirally curved about the axis of oscillation and means to hold the difli'erent relalus of said stylus bar, free ends of said springs in bar is held on said bearm and the oscillation of said stylus bar 0 the tension of said stylus bar,

y the combination of a casing, a diaphragm, a stylus bar, open sided y casing, bearings thereon, a stylus for securing said springs to said casing to impose a tension on said stylus bar and to hold said ects substantially radial distention and contraction of said curved portions about tion, and changes in form and osition of said springs, due to the oscillation of said stylus bar, are confined to. said curved portions.

6. In a sound box, the combination of a casing, said stylus bar interposed between said casing and said stylus bar, a pair of oppositely disposed springs secured to said stylus bar, and each comprising a portion substantially spirally curved about the axis of oscillation of said stylus bar, the center of curvature of said curved portions being close to said axis of oscillation, and means tohold the free ends of said springs in different relatively fixed positions whereby said stylus bar is held on said bearings. a

7 .The combination in a sound-box of a casing, a stylus bar mounted for oscillatory movement thereon and a pair of spring members each coiled in opposite directions about the axis of oscillation of the stylus bar, and having one end secured to the casing and the opposite end secured to the stylus bar.

8. The combination in a sound box of a casing, a stylus bar mounted for oscillatory movement thereon and oppositely coiled spiral spring members arranged transversely -to the axis of oscillation. of the stylus bar and secured at one end to the stylus barf and means for securing the opposite ends 0 said spring members to the casing.

' 9. The combination in a sound box of a bar oscillatably mounted on the bearings, and means for tensioning the stylus bar and retaining the same on said bearings consisting of oppositely coiled spiral spring members arranged transversely to the axis of oscillation of the stylus bar and secured to the stylus bar and to the casing.

10. The combination in a sound box of a casing, a stylus bar mounted for oscillatory movement thereon, arranged transversely'to the-axis of oscillation of the stylus bar, and means for adjustably securingsaid spring members to the casing.

nwitness whereof, I have hereunto set I'ELDRIDGE R. JoHNsou.

said axis of oscillaa stylus bar, knife edge bearings for stylus bar and secured to the.

spiral spring members "my hand this 9th day of November, A. D. 1917.

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