US1480203A - Phonograph and analogous apparatus - Google Patents

Description

Jan. 89

E. GRISSINGER PHONOGRAPH AND ANALOGOUS APPARATUS Filed may 27, 1918 2 Sheets-Sheet 1 I 7* I INVENTOR Jan. 8, 1924. 1,48@,23

E. GRISSINGER 2 Sheets-Sheet 2 INVENTOR )%za,ATToRNEY Patented Jan. 8, 1924i um'rso v 1,480,203 TENT OFFICE.

ELWOOD GRISSINGEB OF BUFFALO, NEW YORK, ASSIGNOR TO LUCY ASH GBISSINGER;

' 0F BUFFALO, NEW YORK.

PHONOGBLAPH AND ANALOGOUS APPARATUS.

Application filed May 27,

To all whom it may concern:

Be it known that l, ELwoon Gnrssnvonn, a citizen of the United States, and resident of Bufialo, in the county of Erie and State of New York, have invented certain new and useful Improvements Relating to Phonographs and Analogous Apparatus, of which the following is a specification.

My present invention is shown as embodied in a phonographic sound box which is primarily adapted for 'mechanically reproduc'ing sound from a record, but may be employed for the reverse process of recording sound upona wax or other impressionable surface. An important object of the invention is to insure faithful transmission through a lever or other similar machine element, of physical movements corresponding to speech vibrations or other vibrations having similar frequencies or similar complexities. Certain features of my invention which contribute to this object are capable of useful employment not only in phono= raphs but also in other instruments wherein iaithful execution or transmission of complex or high frequency movements is necessar or desirabl n phonograph apparatus, the sounds are represented solely by physical to and fro movements of the diaphra'gm, lever and stylus, and the wide variations in loudness, pitch and quality are represented solely by variations in the frequencies, speeds and distances or amplitudes of these physical movements. In recording, the lever is actuated by the diaphragm, and the stylus at the other end of the lever, records the result ing movements as undulations in a groove which the stylus cuts in the moving record. These undulations may be out either in the side walls of the groove as in machines of the Victor talkin g machine type or in the bottour of the groove as in machines of the Edison type. In reproducin the process is reversed, the undulations in t e record'actuating the stylus, lever and diaphragm to reproduce in the air, the sounds corresponding to those originally recorded.

All of the ph sical factors concerned are of extraordinari y small magnitude and the minutest physical or mechanical imperfection shows up as an enormously magnified disturbanceim the sound Iproduced by the phonograph diaphragm. ence, one of the 1918. Serial no. 286,785.

primary objects of my pres ent invention is to secure in a single dance, the required high surfaces. The oscillatorymovemen'ts of the lever are substantially confined to a single plane and all twisting, skewing or other movements or vibrations of-the lever are,

prevented, except only the desired to and fro movements in a direction perpendicular to the diaphragm.

The noiseless, rigid pivoting and noiseless springs and levers free from vibratory movement in directions not perpendicular to the diaphragm are especially important in devices of the Victor talking machine type in which the pivot isperpendicular to the record, and the minute, unavoidable inequalities in the bottom of the groove vibrate the stylus vertically in a direction parallel with the diaphragm, thus causing disturbin noises at the same time that the sound record undulations in the sides of the groove are operating to produce the desired vibration perpendicular to the diaphragm.

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My invention contemplates solving above problems by a construction involving the use of a plurality of resilient elements under enormous elastic tension but applied to the lever in such a way that they are approximately counterbalanced, so far as concerns the desired pivotal movements of the lever in a plane perpendicular to the diaphragm.

The special features of my construction whereby l. secure the noiseless, frictionless, rigid pivoting in combination with any delid sired degree of sensitiveness and ease of the pivotal movement in the desired plane, also makes it possible to secure certain other esfaithful phonographic reproducsentials 0 tion which have not been appreciated or achieved heretofore, either practically or theoretically.

The additional requisite is that the lever should execute and transmit the physical movements corresponding to each and all of the fundamental and component frequencies that is without dis uroportionatelv amnlif 9 l i c r l log any of said frequencies and without disproportionately diminishing any of them.

' The disproportionate amplifying of certain frequencies either fundamental or components, commonly results from mechanical resonance or natural vibration of parts of the vibratory system or o f the system as a whole.

The disproportionate diminishing of certain of the frequencies commonly results from excessive pressure and friction of the stylus on the record-such pressure diminishes the ease and freedom of movement which is necessary for faithful reproduction of the higher-frequency, small-amplitude components of the sound and it operates to damp out such high frequencies more than the lower ones. It is commonly employed however in an attempt to control and damp out the disproportionate amplifying due to mechanical resonance.

Mechanical resonance is therefore the direct cause of disproportionate amplifying of certain frequencies and the reason or indirect cause for the pressure and damping which disproportionately diminishes the higher frequencies. One object of my invention is to do away with the mechanical resonance and so do away with the necessity.

for damping.

My invention recognizes, however, that in apparatus of this kind, the natural elastic qualities which causecmechanical resonance are unavoidable; that the resonance efiects may come from natural vibrations of certain elements of the vibratory system as well as from natural vibrations of the system as a whole; and, finally, that the efi'ects of these natural frequency vibrations can be avoided and completely eliminated from the functioning of the device, by making the natural frequency of the elastic elements too high for audibility in the phonograph and the natural frequency of the system as a whole too low to be objectionable in the phonograph. I believe these two conditions or qualities have never before been embodied in a single instrument. This is because a low enough natural. frequency for the lever requires that the inertia factor be very great or the elasticity factor very small, yet the inertia cannot be great because the. lever must be extremely light in order to properly perform its phonographic functions and the spring elements must have extremely high resilience in order that their individual natural frequencies may be hi her than any of the frequencies that are audible in thephonoa r Y With thev above dificulties and purposes in view, If employ a light but rigid constructron whereby the lever moves as a unit, subleec es stantially without independent or natural vibrations within the range of phonographic frequencies. Furthermore, ll employ 'resilience or spring members under extreme high tension, such as will prevent any disturbing movement or skewing the lever or of its pivotal axis, and such as will raise the natural vibrations of said spring elements to a frequency higher than any of the frequencies within the range mentioned. At the same time, the arrangement of these spring members is such that their enormous tensions are substantially balanced on the lever and there remains only a small resultant resilience available for elastic restoration of the lever. Hence the natural frequency of the whole vibratory system may be kept as low as required even though the lever be very light and the individual EBIIISlODS of the separate springs very power- Having thus eliminated mechanical resonance without rendering the vibratory system either stifi or sluggish, ll am able to use a light sound box with minimum pressure and friction of the stylus on the record. Frictional damping being minimized, the remaining damping factors are mainly those due to internal molecular friction in the material of the vibratory parts. These are approximately constant and their damping effects are not objectionably greater for the high frequencies than for the low frequencies. Hence this kind of damping does not operate to produce noticeable distortion of loo the sounds.

In the present embodiment of my invention, the resilient or spring elements comprise a plurality of highly tensioned wires, clamped on opposite sides of and preferably extending throu h the lever or other movable member. fiach wire has its clamping points or fixed pivotal centers equidistant from those of the other wire and the movable center where the wire engages the movable member, is also equidistant from the movable center of the other wire, so that the actual center of oscillation of the movable member is a line or phantom axis lyingmidway between the clamping axes and the lever engaging axes of the two wires. It is not necessary to have the wires cross this phantom axis but each may have its fixed center and its movable center and its intermediate free portions lying wholly on one side of said phantom axis. In the latter case, it is de sirable to have one set of pivotal centers, preferably the fixed pivots. quiteiclose to the phantom axis while the other set of pivotal centers, preferably the movable pivots, are 5 much more distant therefrom. This makes the stresses of the wires on the movable member equal; When the movable member is permitted to assume its normal position with the fixed centers, the movable'centers and the phantom axis all in the same plane, the stresses become exactly opposite as well as equal and the above described condition of stable equilibrium for the movable member is attained. Preferably this plane is parallel with and close to the plane of the dia phragm. A very simple form of my pivotal mounts mg and one which is most conveniently arranged for elimination of resonance effects, is one where a pair of wires are threaded through transverse passages formed in the lever arm at points equidistant from and on opposite sides of the desired phantom axis. The free ends of the wires are then engaged with suitable clamping means equidistant from but quite close to said axis. Where elimination of resonance is desired the two wires should have their total lengths, the lengths of their free portions and their spread angles preferably equal, the disposition of the wires being thus substantially symmetrical both with respect to the phantom axis and with respect to the longitudinal axis of the lever.

' The nearer one of the pairs of pivotal axes is to the phantom axis, the less power will be required for causing rotary movement about that axis. Hence, in practice quite heavy piano wire, say about No. 6 piano wire which is about .011 to .012 inch in diameter, may be used and may be stretched up to the limit of safe elastic tension, before clamping, with the result that while the natural frequency of the system as a whole remains low enough to be unobjectionable, the natural frequency of the unclamped portions of the wires will be raised so high as to be inaudible or at least unnoticeable in ractice. Moreover, thetensions of the uno amped port-ions being perfect-1y equalized by the portion of the lever arm between them acting as a spreader, it requires only makin them of equal length to make their natural frequencies the same, so

that theyrwill not give rise to secondary or beat equencies. Such secondary frequencies being far lower than the component frequencies of which they are a resultant, are lilrely to be within the range of important speech fre uencies. In practice, however, such vibrations have little energy and it is seldom necessary to make the wires of mathematically exact equal length.

The spread of the wires in the plane of the longitudinal axis of the lever together with their high tension makes the lever absolutely secure against longitudinal displacement. The convergence of the wires between their points of clamping and their points of engagement with ,the lever perfectly stays the lever against any lateral Vlbration and against angular shifting of the axis of its pivotal movement.

v The leverwill besecured against-slipping on the wires by the high tension and by the bends of the wire, particularly where they are of the heavy gauge above suggested, but where lighter wires are used and as a. precaution where heavy wires are used, I may secure them positively as by binding screws or by brazing or by casting them in place on the movable member.

The various features of my invention may be more fully understood from the follow.- ing description in connection with the accompanying drawings of a phonograph sound box in which they are embodied.

In said drawings, F igure l is an elevation of the sound box;

Figure 2 is a section on the line 22, Figure 1;

Figure 3 is a side elevation of the same view endwise of the stylus lever; 1

Figure at is a detail plan view of the wire suspension and clamping means; 7

Figure 5 is a section on the line 5-5, Figure 4;

. Figure 6 is a section on the line 6-6, Figure 1; v

Figure 7 is a section on the line 7-7, Figure 4;

Figure 8 is a detail perspective view of the stylus lever;

Figure 9 is a diagrammatic section showing the disposition and geometrical relations of the pivotal mounting;

Figure 10 is adiagrammatic side elevation showing further geometrical relations;

Figure 11 is a view somewhat similar to Figure 8 but showing a converging arrangement of the pivotal wire mounting and indicating in diagram its geometrical similarity to the diverging arrangement of the wires.

In these drawings, the sound box comprises the annular ring 1, formed with the inwardly projecting annular flan 2, and the back-plate 3, secured to ring li y screws 4. In the recess between flange 2 and plate 3 is clamped the diaphragm 5 of mica or other suitable material, disposed between a pair of rubber cushioning rings 6 which may be of any known or desired material or construction.

' The annular ring 2 is formed on one side with an enlargement 7 adapted to form a solid base support for the mounting of the stylus lever. The backplate 3, is shown as provided with an annular rubber collar 8 carrying an internal ring 9 provided with lugs 10 adapting it for bayonet connection with slots on a phonograph arm where the device is used for reproducing or a mouth piece where the device is used for recording.

The lever arm 11 is attached to the approximate oenter of the diaphragm in'the' usual manner and the opposlte end is rovided with the usual socket 12 and bin ing screw 13 for holding a needle for reproducing or a cutting point for recording, asindicated at This lever is preferably of an aluminum alloy, the long arm of which is made light yet very rigid by giving it the double rib construction indicated in the drawings. The pivotal portion is relatively massive for purposes of strength, and because a certain amount of weight near the pivotal axis is not so objectionable and is in some respects advantageous so'far as concerns pure tone transmission.

The support for the lever arm to permit its pivotal motion around the above described phantom axis as a fulcrum is shown as comprising two wires 15, 16, preferably steel piano wires, symmetrically arranged with respect to the pivotal axis and also with respect to the longltudinal axis of the lever. The wires are secured to the lever arm in any desired way, as for instance, by threading them through passages 17, 18 (Figure 9). These passages are parallel with each other and with the diaphragm. On each side, where the wires emerge from the lever arm, they may be secured by clamping screws, as at 35, 36, Figure l, and the ends of the passages may be slightly rounded or l-ed as at 37, 38, Figure 7, to lessen the abruptness of the bends. From these points the wires are deflected toward each other and bent around closely adjacent pairs of studs or pins 19, 20, on the one side and 21, 22 on the other side and are then drawn through wire clamps 23, on the one side and 24- on the other. In the form shown in Figures 1 .and 3, the clamps comprise relatively massive, rigidly secured stationary members 25, 26, cylindrically concaved on top as at 27, 28 and movable clamping members 29, 30, having corresponding convex clamping surfaces. The wires are stretched to the desired frequency by any suitable tensioning means and are then looked and ed in position by the clamping screws 31, 32.

The spacing between the surfaces of the pins or studs determines the leverage ratio at which the resilience of the wires and the power applied to the lever will interact and this spacing in general will be close sd that the resilient opposition to rotary oscillation of the lever will be small.

A modified form of combined clamp and deflector is shown in Figures d and 5. lln this case the clamping surfaces of the fixed and movable members are spherical instead of cylindrical and the margin of the spherical concavity on the fixed member is centrally cut away to afiord deflecting shoulders 33, 3t 11 ving the same function as the fixed pins shown in Figure 1. The opposite margin of the concave clamping; surfaces is cut away as at 35 to permit straight line application of the required high tension upon the wires previous to clamping them.

Characteristic features of mo ements,

ineoeoa stresses and leverages of the above described pivotal mounting are indicated in the enlarged detail views (Figures 8 and 9).

In Figure 9 the parallel dotted lines b, 2') indicate the fixed pivotal axes and c, c the movable pivotal axes of the wires, while the dotted line a, parallel with and midway b tween them indicates the position of the axis of movement of the lever arm. Figure 9 shows plainly how the wires, when highly tensioned, adord prohibitive opposition to movement of the lever either endwise or laterally. The side elevation shown in Figure 9 indicates how, when a, b, and 0 are in the same plane, the lever is in stable equilibrium. In this position, the stresses on the wires are exactly opposite andtherefore balance. Displacement of the lever in any way whatever requires stretching of the wires between the fixed pivotal points 5 and the movable points 0, but the amount of stretching required and the resulting elastic oppositions are very difl'erent for the different movements. For instance, the desired oscillatory movement of the lever about the line a; as an axis requires stretch-- ing only the difi'erence between are e and are d, while the undesired vertical bodily displacement of the lever in the direction of the parallel lines f, f requires stretching the greater distance measured by the difference between are c and tangent 7". Moreover, the desired rotary movement about line a; as. a center is favored by advantageous leverage, the very small radius al determining a very short weight arm for the leverage as contrasted with the very long power arm adorded y the len th of the lever between a and the end 0 the lever where the power is applied. Hence, for the desired rotary movement, the opposition and the resilient restoration afforded by the wires, is extremely small as compared with the opposition and resilience which they have with respect to forces tending to displace them in the direction of lines 7, f. The un= desired noise-producing movement of the lever parallel with the lane of the diaphragm is most powerful y resisted by having the wires arranged in said plane because as will be seen from Figure 10, this presents the wire endwise to such stress so that the movement cannot be any greater than the stretching. That is to say, with respect to this movement, the wire tension is applied. in directions of maximum efiectiveness as compared with the lesser effec tiveness with which they operate to oppose motions in the other directions above considered.

In ,Figure 11, l have shown how closely the above described adj acently clamped and intermediately spread wire suspension may be the equivalent of a converse arrangement in wh ch the wires are clamped at remenace mote points and are deflected to pass through the lever in parallel passages on opposite sides of and closely adjacent the lever axis. By reference to the figure, it will be seen that when the lever is widened by the trunnion- like extensions 40, 41, the two systems are equally effective for determining a fixed pivotal axis for the lever, for easy .movement about said axes and for practical prohibitive opposition to motion in any other direction or about any other axis. The principal difierence seems to be that in the arrangement shown in full lines in Figure 11, the torsional strain on the wires is located, at the points where they engage the lever rather than at the points where they engage the clamps. This renders clamping or brazing the wires to the lever more important thanin the preferred arrangement first above described. It will be noted also that in Figure 11. the distance between the clamps must be increased by an amount equal to the combined lengths of trunnions 4:0, 41.

I claim:

1. In a phonographic sound box, a pivoted lever in combination with means for resiliently pivoting said lever, said means comprising piano steel KWHQS et-rically arra and clamped on opposite sides of the pivotal axis and stretched to a tension approximating the safe elastic limit of said wire, for the purpose described.

2. A rigid member, a pair of clamps rigidly mounted thereon and an oscillatory member pivoted between said clamps, the pivotal means comprising a plurality of transverse wires arranged syetrically with respect to each other but each lying wholly on one side of the desired pivotal axis, secured attheir ends in. mid clamps and havin their intermediate portions engaging said pivoted lever, each wire having the radial distance from the pivotal axis to the fixed pivotal point and to the lever engagement point substantially difierent, and one of said radial distances being very small, and one of them the oger. h Ph (1 b0 1 3. a p onogra ic soun x, a pivoted lever transversely rigid throughout, in combination with a pivotal mounting therefor comprising spaced steel wires setricy arranged, highly tensioned and clampfl on opposite sides of the pivotal axis, the and tensibn of said wires being predetermined with t to the weight and length of the lever so that the vibratory system including lever' and wires has but one noticeable natural frequency of vibration, said uency beg below the important uencies of speech and music.

4. In a phonographic sound an, a pivoted lever transversely rigid throughout, in

much greater than combination with a pivotal mounting therefor comprising spaced steel wires symmetrically arranged, highly tensioned and clamped on opposite sides of the pivotal axis, with their free portions between the clamps and points of engagement with the lever substantially equal and equally deflected in a direction lengthwise of the lever,-the spacing and tension of said wires bein predetermined with respect to the weig t and length of the lever so that the vibratory system including lever and wires has but one noticeable natural frequency of free vibration, said frequency being below the important frequencies of speech and music.

5. In a phonographic sound box, a pivclamps and points of engagement with the lever substantially equal and equall fie ct'ed in a direction len hwise of t e lever.

6. In a phonographic sound box, a. piv-.

oted lever, in combination with a pivotal mounting therefor comprising spaced steel wires symmetrically arranged, highly tensioned and clamped on opposite sides of the pivotal axis, with their firm portions be tween the clamps and points of engagement with the lever deflected in a direction lengthwise of the lever.

7. In apparatus of the class described, a. suitable support and a vibratory system in- 111': in combination, a diaphragm, styl ever and pivotal elements engaging the lever to rigidly predetermine and fix its pivotal axis parallel with the diaphragm and to elastically and resiliently position the lever with respect to its normal position of rest, at least one of said pivotal elements being a short length of steel wire stretched to extreme high tension between the lever and its support at an angle to the pivotal axis and in such direction with respect to the other pivotal element or ele-- ments as to afl'ord extremely slight resilient opposition to pivotal movements of the lever in a plane at a right angle to the diaphragm. I

8. In apparatus of theclass described, a

suitable support and a vibratory system ill-- eluding in combination, a diaphragm, .a rigid lever rigidly connected to the diaphragm at one end and ha a stylus at the other end in combination with ivotal elements enga the lever to rigidly predetermine and 1 its pivotal axis paral-- lel with the diaphr and to elastically and resiliently position the lever with respect to its normal position of the nat= nrel frequencies of vibration of the resilient elements of the vibratory system being too high end the natural frequency of the system as a Whole too low to be noticeable in plionograpllic reproduction 9. In apparatus of the class described, a suitable support and a vibratory system including in combination, a diaphragm,

stylus lever andl pivotal elements engaging the lever to rigidly predetermine and fix its pivotal axis parallel with the diaphragm and to elastically and resiliently position the lever with respect to its normal position of rest, at least one of said pivotal elements being a short length of steel Wire stretched. to extreme high tension between memos the lever and its support but in such direction with respect to the other pivotal elemeat or elements as to afiord extremely slight resilient opposition to pivotal movements of the lever in a plane at a right angle to the diaphragm, the natural treqneneies of vibration of the resilient elements of the vibratory system being too high and the natural frequency of the system as a wl ole too low to be noticeable in phonographlc reproduction.

Signed at New York city, in the county of? New York anal State of New York, this 25th day of May, A. D. 1918.

ELW'CDQD GRISSINGER.

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