US2648726A - Control device for electrical circuits - Google Patents

Description

H. c. WARNER 2,648,726

CONTROL DEVICE FOR ELECTRICAL CIRCUITS Aug. 11, 1953 Filed Sept. 2, 19 49 3 Sheets-Sheet 1 INVENTOR.

ZZZRRYGMR ER.

Z5 I BY W if W ATTORNEY Aug. 11, 1953 2,648,726

H. c. WARNER CONTROL DEVICE FOR ELECTRICAL CIRCUITS 5 Sheets-Sheet 2 Filed Sept. 2, 1949 1'72 .21. R EF-* 1 l '1"; E6 5,901 76 79 6 95 4 1 :19.14. 68 I 63 78 a2 ATTORNEY Aug. 11, 1953 H c. N R 2,648,726

CONTROL DEVICE FOR ELECTRICAL CIRCUITS Filed Sept. 2, 1949 3 Sheets-Sheet 5 IN V EN TOR.

/78 HARRY 0. WARNER ma:- o BY 1 a 4 a Patented Aug. 11, 1953 UNITED STATES i ATENT OFFICE CONTROL DEVICE FOR ELECTRICAL CIRCUITS 21 Claims. 1

This invention relates to an improved control device for electronic circuits. More particularly it relates to such control devices as phonographic sound reproducing apparatus and microphones, especially to new and novel types thereof employing a liquid current-modulating medium. The present application is a continuation-in-part of application Serial No. 738,159, filed March 29, 1947, now abandoned.

The invention solves such problems in pickups as the elimination of distortion, the transmission of a wide range of well-modulated frequency responses, and reduction of needle scratch to a negligible amount. It accurately transmits the mechanical variations in frequency and amplitude (recorded in the record groove) into corresponding variations in electrical current. It is fully responsive to the lateral variations of the record groove, but it is relatively unresponsive to vertical variations, which are abberations and r if transmitted cause undesirable extraneous noises. Needle scratch, for example, is caused mostly by such vertical aberrations traceable to roughness in the bottom surface of the record groove.

In the present device these vertical aberrations are cancelled out and are not present in the output. In addition, because of the very excellent fluid damping in the present invention, mechanical resonances traceable to the moving parts are also absent from the output. The invention thus overcomes most of the deficiencies of crystal pickups while still providing a very lightweight relatively inexpensive pickup. It also has great advantage over magnetic pickups because 5 adjoining chambers which contain an electrolyte.

Each chamber has an electrode and two variablearea orifices are provided to connect one chamber with the other two. Means are provided for varying the area of these orifices in accordance with externally originating motion such as the Moreover the lateral motion of a phonograph needle or the lateral motion of a microphone-diaphragm. As the orifices vary in area in accord with the motion of the needle or diaphragm, the resistance between the electrodes in each chamber varies. By properly connecting the electrode of the center chamber with one part of an electronic circuit and the electrodes of the outer chambers to other parts, the voltage of the center chamber electrode will be varied in accordance with the originally reproduced sound, and this voltage variation may readily be amplified. With the two outer chambers set to balance each other for vertical variation, the vertical component of the needles motion can be substantially cancelled from the output.

Other objects, advantages, and uses of the invention will be in part evident to those skilled in the art and in part pointed out hereinafter in connection with the accompanying drawings, wherein preferred embodiments of the invention are shown, by way of illustration and not of limitation.

In the drawings:

Fig. 1 is a plan view of a pickup unit embodying the principles of the invention, with a portion thereof broken away and'in section to reveal inner details.

Fig. 2.is a side view of the pickup unit of Fig. 1 taken along line II-II of Fig. 1.

Fig. 3 is a plan view of the bottom portion of the pickup shown in Fig. 1.

Fig. 4 is a vertical sectional view taken along line IV--IV of Fig. 3 looking in direction of the arrows. p

Fig. 5 is a slightly enlarged sectional view taken along the central plane longitudinally of the pickup of Fig. 1.

Fig. 6 is a slightly enlarged sectional view taken along line VIVI of Fig. 1 looking in direction of arrows.

Fig. 7 is a horizontal sectional view taken along line VIIVII of Fig. 5.

Fig. 3 is a vertical sectional view taken along line VIII-V'III of Fig. 5 looking in direction of the arrows, and showing in an exaggerated manner (for purposes of illustration) the effect upon thevariable orifices of the sidewise motion of the needle.

Figs. 9 and 10 are diagrammatic views illustrating two circuits by which my improved pickup may be connected to a thermionic tube amplifier.

Fig. 11 is a partially exploded view in perspective of a modified form of the invention.

Fig. 12 is a top plan view of the device shown in Fig. 11 with the cover removed.

Fig. 13 is a View in side elevation and in section taken along the line XIII-XIII in Fig. 12, the thicknesses in this and the following views have had to be exaggerated for purposes of illustration.

Fig. 14 is a View in section takenalong the line XIVXIV in Fig. 13.

Fig. 15 is a view in front elevation and in section taken along the line XVXV in Fig. 13,

showing the device at rest and when the needle is in the center of the groove.

Fig. 16 is a view similar to Fig. 15 showing the device when the needle is at one side of the groove, illustrating its efiect on the variable orifices between the chambers.

Fig. 17 is a View in front elevation and in section taken along the line XVIIXV'.[I in Fig. 13.

Fig. 18 is a view in front elevation and in section taken along the line XVIII-XVIII in Fig. 13.

Fig. 19 is a perspective view of a portion of the apparatus of Fig. 11, removed from the housing and having'some of the parts removed to show the other parts'more clearly. I

Fig. 20 is a'view in perspective of theneedle chuck of this modified form turned upside down.

Fig. 21 is a view in perspective of the body member looking down at-its upper face, and with the diaphragms removed therefrom, showing the three electrolytic chambers, the knife edges on the upper ends of the partitions between the chambers, and the electrodes.

Fig. 22 isa plan view looking at the body member of Fig. 21 from below.

Fig. 23 is a view in front elevation of a microphone embodyingjtheprinciples of th'e invention, a portion thereof being cut away to show the interior portions. v r

Fig. 2 lis a viewin side elevationof the microphone of Fig. 23.

Fig. 25 is a view inperspective of a portion of the microphone removed from the microphone housing and having the diaphragm removed from it.

Fig. 26 is a view of the microphone diaphragm and its associated 'supporting'me-mbe'r which actuates the transmission thereof.

Fig. 27'is a top plan view of a further modified form of control device; the view is somewhat diagrammatic in form andthe chuck and some other parts are removed for the sake of clarity.

Fig. 281.5 a side elevation view of the device of Fig. 27.

Fig. 29 is a view in perspective of the actuating member or chuck usedwith the device of Figs. 27 and 28 in a phonographicpiekup unit, and

Fig. 30 is a diagram of the circuit used in the device of Fig. 27.

In Figs. lto 4, inclusive, is shown the assembly and several of the parts which constitute the principal elements of one-form of-improved pickup. In connection with this description it will be understood that the pickup-u'nit, here shown in substantially its normal size, will be carried at the free end of a tone arm. The tone arm will be supported so that the unit here illustrated may swing freely and may follow the sound track in a record of the disc type. It will also be understood that if the device should be used in connection with cylindrical or tape types of recording, it will be carried over the cylindrical or tape record in the conventional manner of such machines.

In Figs. 1 to 4 the pickup, designated broadly by the numeral it, is shown as comprised of an upper body forming member 5 l of insulating material within which two cavities or chambers l2 and 13 are formed. In these a quantity of a suitable liquid or electrolyte it may be held. The chambers l2 and B3 are here shown as extending longitudinally of the body member El and in spaced parallel relation to each other. Mounted with the body member 1 l and interposed between the two chambers l2 and i3 is a cylindrical wall forming member it. As will hereinafter appear, the wall 55 serves to form a third chamber 15 for containing a further quantity of said liquid or electrolyte I l within the body member ll.

As is more clearly shown in Fig. 2, the bottom ends of the chambers E2, E3 and it are open. The open ends are coplanar, and their plane is normally positioned horizontally. A flexible diaphragm ll, shown across the lower surface of the body member H, closes the open bottom ends of the chambers i2, i3 and i5. Preferably this diaphragm I? in the form or a sheet of soft rubber or latex is clamped'between the lower side of the body member ii and a metallic plate 58, by means of screws lfl'which are disposed centrally at each end thereof.

A terminal supporting member 29 of insulating material extends outwardly from one end of the plate i8. Terminals 21, 22 and 23 are held in spaced relation on the member 2d. These terminals 2 l, 22 and 23 are respectively connected through conductors 2 3, 25 and 26 with electrodes El, 28 an'dtt which are disposed respectively withinthe chambers l2, l3 and it of the body member ii. At this point it may be stated that the electrodes 2?, 28 and 29 here-referred to may be formed by a metallic plating upon the inner vertical walls of the chambers l2, l3 and it within which they are respectively disposed. Or they may be in the form of a thin strip of metal foil which is bent to fit within these chambers and remain immersed in the electrolyte i l with which, as previously suggested, these three chambers are at least partially'filled. Or rod or plate electrodes inserted inside the chambers l2, l3 and ld-may be used instead.

As shown in Fig. 2 of the drawing, the unit it, as a'whole, together with the free floating end of the tone arm support (not shown) which carries this unit may be lightly supported by a record engaging needle 3%. The needle 36 is adapted to follow the sound track of a disc type record 35 here outlined by dot and dash lines. As will he-rw inafter appear, the record tracking needle 38 is adapted to operate uponthe flexible diaphragm H and cause it to be flexed. This flexing causes the orifice openings between the chambers 12 and I6 and between the chambers i3 and 55 to vary in area. When this happens, the current flowing in the electrolyte i l between the electrodes 2! and 29 and between the electrodes 28 and 28 encounters oppositely varying resistances in the orifice openings, and the result is that the chamber-tochamber voltage across the orifices will vary correspondingly. In other words this flexing of the diaphragm H is adapted to provide for variations in the electrical potential between the electrode 29 and the two electrodes El and 28 as the record engaging needle 3i! swings from one side to the other in following the sound track upon a record.

In Figs. 3 and 4, the bottom plate 58 of the pickup unit it is shown as formed with two elongated recesses 32 and 33. These recesses 32, 33 register with the chambers 12 and it formed in the body member ll. At the point where the cylindrical wall-forming member iii is positioned, there is a deeper recess 34 with a central opening 35 within which a needle supporting member is positioned and held in cooperating relation with the flexible diaphragm [1.

Reference is now made to Figs. 5 and 6 of the drawing for a more detailed description of the manner in which the record engagin needle 39 is supported in cooperating relation with the flexible diaphragm IT. A needle supporting member 36 is here shown in the form of a button or disclike member. It has a central hub portion 31 into which the upper endof the needle 30 is adapted to be secured either by press fit, as shown, or in the conventional manner by means of a thumb screw, not here shown. The disc-like portion of the needle supporting member 36 also has an upstanding outer annular rim portion 38 which extends into engagement with the under side of the flexible diaphragm II. This annular rim 38 of the needle supporting member 36 is here shown as slightly larger than the diameter of the cylindrical member I5 which forms the inner chamber I6. When in engagement with the flexible diaphragm I3, this rim 38 will prevent or reduce the flow or contact of electrolyte I4 between the chambers I2 and I3 and the chamber I5. In this particular arrangement the needle supporting member 36 is shown as supported in yielding engagement with the flexible diaphragm It by means of a soft rubber cushion 39 which is positioned within the recess 34 of the member I8. As a means for varying the action of the needle supporting member 36 upon the flexible diaphragm I1, I may, as is shown in Fig. 6, provide the member I8 with a pair of oppositely disposed set screws 40 which will enga e with a relatively thin annular washer 4| that is freely movable within the recess 34. In this way by adjustin the position of the set screws 40 it will be possible to vary the yielding pressure that will be exerted at the side of the needle supporting member 36 by the soft rubber cushion 39.

For the purpose of describing the operation of my invention, reference is now made to Figs. '7 and 8 of the drawing. As will be seen in the former figure, the cylindrical member I5 which forms the inner chamber I6 is fitted tightly within a central wall forming portion 42 of the body member II and in conjunction therewith provides for a permanent seal and obstruction to the flow of electrolyte directly from the chamber I2 to the chamber I 3 and vice versa. In other words, any electrolytic contact which is made will be made via the intermediate chamber I6 formed within the cylindrical member I5.

In this connection, it should be mentioned that while the flexible diaphragm I! is shown in Fig. 8 as flexed outwardly to an extent which might appear to uncover that portion of the cylindrical member I5 which is immediately adjacent the wall 42 of the member I8, this is not the case. In this showing the needle 39 is deliberately shown as oil-set to an abnormal degree so as to magnify the degree of flexure of the flexible diaphragm I7, but in actual operation it will be understood that the swing of the needle 30 will be only a matter of a few thousandths of an inch as will be determined by the sound track upon a record. The electrolyte-flow-controlling movements of the diaphragm I! will also vary in a small degree, which may be plus or minus one one-thousandth of an inch.

Under these conditions (see Fig. 8) it will be seen that as the record tracking needle 30 swings from one side to the other of the medial line of 6 the pickup unit ID, the needle supporting member 36 will be caused to rock upon its supporting soft rubber cushion 39. The member 36 will then exert more or less pressure against the under side of the flexible diaphragm H at the points where the lower edge of the cylindrical member I5 lies within the limits of the chambers I2 and I3. This will alternately establish changes in liquid contact areas between the electrolyte within the chamber I6 and the electrolyte in the chambers I2 and I3.

Therefore when the unit I0 is connected into the input circuit of an amplifier system, and a potential impressed thereupon, the needle movement will cause a modulation of the resistance to the current flow between the electrode 29 in the chamber I6 and the other electrodes 21 or 28 of the chambers I2 and I3. This current flow is indicated by the arrows applied to this figure. It

will be also understood that similar conditions of current flow impedance will be subsequently established between the electrolyte I4 in the chamber I6 and the electrolyte I4 within the chamber I2 when the needle 30 is in the other extreme of its swinging movement.

Certain important points in the operation of the device may be noted here. The basis of operation is the varying of orifices between a center chamber and two chambers on either side which are not connected together. The variation of the orifices is produced by the mechanical variation of the needle 30 in the sound track of the record 3|. When one orifice (as between chambers I2 and I6) is opened wider, the other orifice (between chambers I3 and I6) is narrowed, and vice versa. Thus a push-pull mechanical variation of the orifice areas is obtained in normal operation on a laterally cut record. The electrical potential of the electrolyte and pickup electrode in chamber I I5 will tend to approach the potential of whichever chamber I2 or I3 is at that time connected by the larger orifice. Vertical motion of the pickup needle causes the orifice areas to increase or decrease in unison so that they do not produce any shift in the potential of chamber I6 relative to chambers I2 and I3. This simultaneous operation eliminates the vertical component almost completely, so that all the variation is produced by the lateral movement of the needle. Thus the record groove produces all the electrical eflects, and there will be no response to the vertical component of extraneous efiects, such as needle scratch. Moreover, the tension on the diaphragm I! is so adjusted that the conductivity through the orifices between the electrodes varies linearly with the lateral movement of the needle 30.

While no particular type of liquid conducting medium or electrolyte I4 has been specified hereinabove, it may be stated that practically any liquid medium having current conducting characteristics may be employed. In the present instance, since the chambers #2, I3 and I5 are substantially sealed off from the outside, it is important to provide an electrolyte or liquid current conducting medium I4 which will be substantially free from gassing when in operation. I have found that one such electrolyte, which has been found to be admirably suited to the particular structure hereinafter described, may be formed by a solution of cadmium sulphate in ethyl alcohol. This solution is practically nonpolarizing, and when used with cadmium electrodes 27, 28 and 29 the device has beenfound to produce most satisfactory results. This it is believed'may beexplained by the fact that cadmium ionizes faster than any other comparable metal. Where the electrodes are of this latter type, I prefer to use thin strips of shim steel of one-thousandth inch in thickness and apply the cadmium plating thereto.

Another suitable electrolyte is a solution of alum (potassium aluminum sulfate) in ethylene glycol. The conductivity of this electrolyte may be. increased by the addition of some potassium or sodium iodide. In this instance I have found that the electrodes El, 23 and 29 may be made from a nickel silver alloy containing about 18% silver. A current conducting gas, such as argon or neon, may also be: used as the fluid medium for conducting the modulated current between the several electrodes of the device, as the record tracking needle 30 operates upon the diaphragm or-ilexible sealing means ll.

In Fig. 9 of the drawing, I have diagrammatically shown my pickup unit ill constructed as above described in connection with the input circuit of a push-pull amplifier. In this diagram theamplirier is shown as having two input tubes 43 and i l, eachof which is of. the conventional three electrode type. When my pickup device is used' in this manner the electrode 29 will be connected through a source of potential, here provided by a. battery 55,.to the cathode circuit 46 which feeds into the cathodes of the thermionic tubes 43 and M. This circuit also includes a conventional cathode bias resistor-condenser assembly ll. The battery 35 is here shown as having its positive side connected to the-electrode 2 9, however the polarity of the battery has no effect on the operation of the pickup. The electrodes 21 and 28 are connected respectively to the control grids of thethermionic tubes 63 and Ml. The circuit from the electrode 2? is traced'through the conductor 24, a blocking condenser 48, and a conductor 39. Likewise the connection from the electrode 2% may be traced through the conductor 28 to a blocking condenser Eli and aconductor 5|, which connects with the control grid of the thermionic tube 33. Bypass resistances ii2'and 53 are also provided across the grid to filament circuits of the tubes 43 and 44. Resistors 58' and 58 serve asD. C. return paths for the currents back to the battery;

Fig; diagrammatically illustrates another system. of connectionsby which my pickup unit ill may be employed with a thermionic tube amplifier of the type having a single input tube. In this instance, as here shown, a potential is impressed across the terminals 2'6 and 28 of the unit Ill by means of a battery 54, and the electrode 29 is connected through a blocking condenser 55 to the control grid of a thermionic tube 55. The negative side of the source of potential here provided by the battery 55 is shown as grounded, and in this manner the tube controlling circuit is completed through ground to the cathode circuit of the thermionic tube '56.

It is believed, with the above description taken in connection with the diagrammatic showings of Figs. 9 and 10 and the description given in connection with Fig. 8 of the drawing, that the operation of this device will be fully understood by those skilled in the art, and while I have, for the sake of clearness and in order to disclose the invention so that the same can be readily understood, described and illustrated a specific form and arrangement, it is to. be understood thatthe invention is not limited to the specific-form disclosed, but maybe embodied in other forms and arrangements that will suggest themselves to persons skilled in the art and it is desired to claim.

it so that all such changes as come within the scope of the appended claims are to be considered as part of this invention.

A modified form of pickup 60 also embodying the invention is shown in Figs. 11 to 22. This pickup fill may be used in the same circuits as the pickup id, or either type of pickup may be used in still different circuits.

The pickup 60 (see Fig. 11) is supported in. a

housing member 8! which is open at the top and.

is closed there by a cap plate 62. The pickup 60 includes a body member 53, made from an insulating material, and a pickup chuckfi l which holds the needle 65. In this case the needle 65 is shown as a small sapphire secured to the end of the chuck 54, but other types of needles may be used.

The body member 63 is shown by itself in Figs. 21 and 22. In the form shown here it comprises a rectangular block of plastic recessed to provide three chambers 56, M, and as which extend therethrough from top to bottom. The chambers 6t, 6?, and 68 are preferably parallel to each.

other and extend for substantially the length of the member 63. They are separated by vertical partitions 89 and E0. The bottom surfaces of the body member 63 and the partitions 69 and i0 terminate bluntly and in the same plane. In the upper side, they also all end in the same plane, but I prefer that the partitions 69 and 10 terminate in sharp upper edges ii and i2. (See Figs. l5, l6 and 21.) arch in the front and rear ends of the three chambers 66. 6t, and 53 from the bottom to the top, sothat their upper open ends are smaller than their lower open ends. (This shows clearly in Figs. 21 and 22.) The body member 63 is preferably relieved at each end of the centerchamber Bl by cup-like depressions, l3 and 14 (see Figs. 13 and 21), as an aid to the pivotal support of the chuck E i, explained below.

Wire or rod electrodes l5, ii, and 78 pass through the three chambers 68, El, and 6B, and lead out therefrom through sealed openings in thebody member 53. Additional electrode surface area may be obtained by bending the electrodes l6, H, and id, substantially as shown in the drawings. This also serves to relieve stresses that may be set up when the electrodes are installed. The electrodes l6, El, and 78 are electrically connected to three terminals 19, 39, 8! which are themselves held by an insulator plate 82 at one end of the housing 6%. They may be connected into a circuit of the type shown in Figs. 9 and 10.

A rubber or latex closure sheet 83 is cemented tothe bottom surface of the member 63, and it effectively seals off the chambers 66, El, and 68 from each other at their lower end. (See Figs. 13, 15 and 16.) The chambers 66, 61, and 68 are substantially filled with the electrolyte l4, though a small quantity of air is permissible where a liquid electrolyte M is used. Then the upper end of the body member is closed by a diaphragm 84. (See Figs. 11, 13, 15, 16 and 19.) The diaphragm '84 is cemented to the outer border of the body member 63, but not to the sharp edges H and 72, because the diaphragm 84 cooperates with the edges ii and 72 to form variable area orifices between the chambers 56 and 61 and between the chambers Bl and 68. Preferably. the diaphragm 84 is made from latex rubber, such as dentists use for a dental dam. It

Also, I prefer to bowl or:

sagas and the sheet 83 may both be about 0.010 inch thick. The soft elastic gives an almost perfect response, following modulation up to kilocycles and even higher. The fluid I4 efiectively damps the diaphragm 84 and chuck B4 to prevent the formation of secondary impulses due to recovery of the elastic and to the naturally resonant frequency of the chuck. In this manner the size of the orifices can be varied according to the flexing of the diaphragm 84.

The flexing of the diaphragm 84 is accomplished by the movement of the chuck 64, which transmits the horizontal movement of the needle 65 in the grooves of a record.

The chuck 64 includes a central pivot member 85 and two outrigger rods 86 and 8?, parallel to the member 85 and spaced from it. (See Figs. 11, 12, 13, 15, 16, 19, and 20.) The pivot member 85 is relieved in the center and sharpened at each end to give slightly blunt pivot surfaces 68 and 89. These pivot members 88 and 89 rest on top of the diaphragm 84 and bear it against the body member 63. The cup-shaped recesses '13 and 14 provide relief so that only the pivots 88 and 89 themselves will bear against the body 53 (through the diaphragm 84). As shown in Fig. 19, brackets 96 and SI are provided to hold the chuck ea in alignment adjacent the pivot members 88 and 83. Soft gum rubber members 92 and 93 lie between the member 85 and the brackets 9t and SI so that there will be adequate resiliency and give.

The rods 86 and 81 are positioned to lie parallel to and just outside the sharp edges TI and I2. (See Figs. 15 and 16.) When the needle 65 moves from side to side in the record groove, the chuck 64 pivots on members 88 and 89, and the rods 88 and 81 flex or release the portion of the diaphragm 84 which they bear against. This produces a change in the size of the orifices between adjacent chambers, and since the current passage is quite narrowly concentrated, a change in the size of the orifices produces a definite modulation in the voltage drop between adjacent cells or chambers. The positioning of the electrodes is not critical but the location shown here is ideal for good response.

In order to hold the pickup 6B firmly in the housing without affecting the pivot points 89 and 90, a plurality of soft rubber snubbers 95 may be afiixed to the diaphragm 84 directly over supporting areas of the body member 63. An indented portion 95 of the plate 52 contacts these snubbers 35 and holds the pickup unit firmly. This pressure also helps to maintain the seal of the diaphragm 84 at the extremities of each knife edge 'II and I2.

The operation of the modified device is substantially the same as that of the form shown in Figs. 1 to 8. A potential is set up across the electrodes I6, 17, and 78, preferably about one-half to one volt, and the changes of voltage of the center electrode T! are amplified electronically. As the needle 65 moves horizontally across the grooves, the chuck 64 pivots from side to side. The outrigged flex rods 86 and 8! press against the diaphragm 84, and this pivotal movement increases the pressure on one side while decreasing it on the other. The vertical components may be balanced out of the circuit as explained above. The orifices between the center chamber 6! and the side chambers 66 and 68 vary in size, and as a result the voltage drop across each orifice varies. The diaphragm 84 is responsive to minute changes, and responsive to all the modulations.

The resistance of each orifice and the proportion 10 ate voltage drop are therefore similarly responsive, while the extraneous effects (e. g. vertical movement) are canceled out. The resultant purified electrical modulations may be amplified as much as desired.

The structure of the pickup has some advantages over that of pickup I I) in that the placement of the working gaps on the upper surface'of the plastic body affords a somewhat improved high frequency response as well as freedom from sediment settling in the Working gaps.

The pickups I0 and 60 are very responsive. Yet they are light in weight. They exert less needle pressure on the record than most crystal or magnetic pickups, and they have the advantage of canceling out the extraneous effects of vertical movement. The device is simple and capable of quantity production at a price well below that of pickups which give a comparable accuracy of reproduction.

Another application of the principles of the invention is shown in Figs. 23 to 26. Here practically the same unit as that shown in Figs. 11 to 22 is used as a microphone.

The microphone includes a hollow housing I93, which is supported on a stand IilI. The housing I00 is closed on all sides except the front, which is covered by a wire screen mesh protector IE2, as is conventional.

The body member 63 may be cemented or otherwise secured inside the housing Ice, in a horizontal position as shown, or may be positioned otherwise. The member 63 is identical to the body member 63 described above and shown in Figs. 11 to 22, having the three chambers 66, 61, and 68 and their electrodes I6, TI, and I3. The electrolytic fluid I4 is contained by the body member 53, the closure sheet 83, and the latex diaphragm 84.

A microphone diaphragm I05, comprising a thin strip of metal such as aluminum foil, is supported on a cross-shaped chuck me which functions in a manner similar to the chuck B4. The diaphragm I05 may be dimpled at I 0''! and I88 for additional stiffness, and its lower edge I09 may be cemented on the central pivot member I50 of the Supporting member I06. Supporting vanes I I I and I I2 may extend out perpendicularly from the diaphragm I95, and these may be cemented or otherwise secured to the cross arm II3 of the chuck I06.

Sound vibrations will produce corresponding movement of the diaphragm I05, and this will cause the chuck I 06 to rock back and forth on its pivot member III]. The pivot member III) may be mounted exactly as the pivot member 85, de-

- scribed above, so that it will rock in response to the vibration of the diaphragm I05, on pivot points which are held beneath end brackets H5 and H6.

The brackets H5 and III; also hold the ends of two spring members I I! which exert downward pressure on the latex diaphragm 84 through the sponge rubber pads H8. By this means the diaphragm 84 effects a seal with the partitions II 'tivity is obtained by this construction. The wiringdiagram may be similar to'that for'the pickup unit.

The 'sound vibrations 'cause the upright "diaphragm I to vibrate and torock'th-e chuck I06.

This rocking correspondingly varies thesize' of the orifices between the chambers. The variation in the size of orifices produces a' corresponding variation in resistance between the chambers, and this in turn varies their'potential in theman'ner already explained.

Figs. 2'1 to30 showa modified form 'of-control device I55 which may be'u'sed Where a considerably greater voltage output is required. In this "modification, several sets of cells or chambers are arranged in tandem and a common actuating member controls'the multiple orifices. The output lead lines from each group of three cells are so connected that their effectsare added.

The control device I50 includes a body member I5I in which there are a plurality'of rows of'chambers, three chambers in each row. Here three rows I52, I53, and I55 are shown, the numbering beginning at the left of 'Fig. 27. The first row I52 includes chambers I5I, E62, and I63. The two side'chambers IISI "and I53 are next to and communicate'with the center chamber I62 through variable-size orifices as a diaphragm I55 is flexed. These'co'nd row includes chambers I64, I65 and I55, and the third row I5t includeschambers I51, I58, and

I69. All ofthe chambers contain thefiuid I l, and all of them have their respectiveelectrodes I1I-I19. The electrode 'connections' will be explained later in connection with the circuit.

A chuck I80 has acenter'pivot arm I8! and 'as mlany cross arms as there are rows inthis case there are three'cross arms I82, I83, and 18A. Rocking of the chuck I80 in a manner similar to that already described in' connection with ;tery I92, places a potential across the electrodes HI and I13 in the side chambers IBI and I63. Inthe row I53, the battery I93 creates a potential across the electrodes I14 and I16 in .theside chambers I64 and 565. In the row I54,

the battery I94 creates a potential acrossthe electrodes I11 and I19 in the side chambers I51 and IE9.

The center electrode I12 in chamber I62 of row I52 may be connected to one of, the outer electrodes I14 of the next row 153. Similarly. the center electrode I15 of row I53 isconnected to the corresponding outer electrode 111 of row I54. The resultant output between the electrode Ill and the electrode I18 will have an amplitude three times that across any one of the rows I52, I53, and I54. Output multiplication in this manner is limited only by the mechanicaland electrical complexity which is incurred by increasing the number of cell sets.

Thecontrol device of this'invention is capable of still further uses, of'which five additional ex- -amples' will be listed here:

"(-1)' Referring to Fig. 10 if "t battery. .z

trode '29.

= replaced witha source of alternating potential such as'an audio or a R. F. oscillator, then the vibrations of the needle "59 or "diaphragm I55 would serve to modulate the amplitude of alternating potential appearing on the'output elec- The pickup could then function as alow level modulator for a radio transmitter.

(2) Still referring to Fig. 10' if an alternating potential is impressed across theel'ectrodes 29 and 28, through a capacitator of appropriate size, then the phase of the voltage appearing across the electrodes 29 and 28*can be made to vary with the movement'of the pickup needle 50. Thus the pickup can constitute a source of phase modulation for frequency-modulated or phase-modulated radio frequency transmission. Frequency modulation can also'be accomplished by connecting the electrodes 28 and 29 (Fig. 10) in one leg of a Wien' bridge or a similar oscillator circuit. v

(3) Still referring to Fig. 10, if a resistor of proper size (e.*g., 200,000 ohms) is c'onnecte'd'in series with the lead 2 between the'batt'ery '5fi and the electrode 2?, then laterally responsive and vertically responsive outputs'may be separately and simultaneously obtained from the pickup. The -laterally responsive'output 'will appear on the electrode 29 and. the vertically responsive output will appear on the electrode 21. V

(4) The invention is also'readily adapted to perform as a strain gauge, vibration pickup, sensitive limit control, and other similar instruments.

(5) The voltage output of the pickup is readily controlled by the applied D. C. potential. This feature maybe used to adapt the output of the pickup to the gain of the associated amplifier.

(6) The device may also be used in a submarine sound pickup wherein it can'be adapted for underwater locating work and "for use in depthfinding devices.

Still other advantages and uses will be apparent from the above description, in accordance with which I claim. as my invention:

1. In a control device for electric circuits, the combination of a body member ofinsulating material having three chambers, said chambers including means for retaining a current conducting fluidpan electrode'in'each of "said chambers, two variable-area orifices-having means for connectingone of saidchambers to cach'of the other two, whereby'the resistance between the electrodes is varied as the size of the orifices variesyand means for varying said orifices-in tandem, so that one is widened to a greaterarea as-the'other is narrowed to asmaller'area, and so that an increase in resistance throughone orifice is balanced by a decrease 'inresistance through the other orifice.

2. In a-control device for electric circuits, the

- combination of a-body member of insulating materialhaving three chambers, said chambers including means for retaining a current conducting fluid, an electrode'in each of said chambers, two variable-area orifices having means for connecting one of said chambers to each of the other two whereby'the resistance between the electrodes may be varied, and means to vary saidorifices in tandem in' response to externally originating motion, so that one orifice is widened as the other orifice is narrowed, whereby the increase-in resistance through'one orifice'is balanced by a decrease in resistance through theother orifice.

3. "A control device for electric circiiits comamaze prising a body member of insulating material having a center chamber and two side chambers therein, an electrode in each of said chambers, electrolytic fluid in said chambers, means defining a variable area orifice between said central chamber and each of the two side chambers to which orifice said fluid has free and unobstructed access at all times, and means for varying in tandem the area of said orifices in response to externally originating motion, so that one said orifice is widened as the other said orifice is narrowed and thereby the increase in electrical resistance through one said orifice is always balanced by a corresponding decrease in electrical resistance through the other said orifice.

4. A control device for electric circuits comprising a body member of insulating material having a center chamber and two side chambers therein, an electrode in each of said chambers, electrolytic fluid in said chambers, means defining a variable area orifice between said central chamber and each of the two side chambers, and means to vary the area of said orifices in response to externally originating motion, the variations in said orifices being maintained in balanced phase opposition by said means.

5. A control device for electric circuits, comprising a body member of insulating material, said body member having three chambers therein; an electrically conductive fluid in said chambers; an electrode in each of said chambers and having terminal connections outside said chambers; a flexible rubber diaphragm covering an open end of said chambers, and cooperating with the body member to provide between a portion of said diaphragm and a portion of said body member an orifice between one said chamber and each of the other two chambers, the area of each said orifice being varied according to the flexing of said diaphragm; an actuating member pivotally mounted and having two portions that bear against said diaphragm, so as to flex said diaphragm in the vicinity of each said orifice and thereby vary their areas substantially equally and oppositely so that an increase in one area is simultaneously balanced by a decrease in the other area; and means mounted on said actuating member to transmit externally originating motion thereto.

6. The device of claim in which the diaphragm-flexing portions of said actuating member are equidistant from the pivot arm thereof and in which said orifices are likewise equidistant therefrom so that the variations in said orifices occur in phase opposition to each other.

7. A control device for electric circuits, comprising a body member of insulating material, said body member having three chambers therein; an electrically conductive fluid in said chambers; an electrode in each of said chambers and having terminal connections outside said chambers; a flexible diaphragm covering an open end of said chambers and cooperating with the body member to provide an orifice between one said chamber and each of the other two chambers, the area of each said orifice being varied according to the flexing of said diaphragm; and an actuating member, pivotally mounted so that part of it bears on said diaphragm adjacent the partitions between said chambers, whereby movement of said member on its pivotal mounting will flex said diaphragm and vary the orifices between said chambers.

8. The device of claim 7 in which a phonograph needle is mounted in said actuating fiiem' ber, so that the device will function as a phonographic pickup.

9. The device of claim 7 in which a voice-responsive diaphragm means is mounted on said actuating member, whereby said device will function as a microphone.

10. The device of claim '7 in which the chamber that is joined to the other two chambers is located centrally between them.

11. The device of claim 10 in which said central chamber in cylindrical and in which the actuating member includes an annular pivotal mounting on said housing and an annular ring which bears against the diaphragm adjacent the walls of said outer cylindrical chamber so as to widen the orifice between the center chamber and one of said other chambers when the actuating member is moved laterally, and at the same time to narrow the orifice between the center chamber and the remaining chamber.

12. The device of claim 7 in which the partition walls between chambers terminate in a sharp edge adjacent the diaphragm at the locus of each orifice.

13. A control device for electric circuits, including in combination: a body member of insulating material, said body member having three chambers therein parallel to each other; an electrically conductive fluid in said chambers; an electrode in each of said chambers and having terminal connections outside said chambers; a flexible diaphragm covering an open end of said chambers and cooperating with the body member to provide an orifice between one said chamber and each of the other two chambers, the area of each said orifice being varied according to the flexing of said diaphragm; and an actuating member, pivotally mounted in an axial line along the center chamber and having two rods secured parallel thereto and bearing on said diaphragm adjacent to the partitions between chambers, whereby movement of said member on its pivotal mounting will flex said diaphragm and vary the orifices between said chambers.

14. In a control device for electric circuits, the combination of a body member of insulating material having two spaced chambers, said chambers having means for retaining a current conducting liquid, a third chamber adjacent the two spaced chambers of said body member also having means for retaining a quantity of said current conducting liquid, means defining two variable area orifices one of which makes the connection between each of said spaced chambers respectively and the said third chamber, the area of said orifices being responsive to externally originating motion and means for varying said orifices in tandem, whereby an increase in the area and decrease in the electrical resistance at one orifice is simultaneously balanced by a corresponding decrease in the area and increase in the electrical resistance at the other orifice.

15. A phonographic pickup, comprising a housing; a body member of insulating material secured within said housing, said body member having three chambers therein; an electrically conductive fluid in said chambers; an electrode in each of said chambers and having terminal connections outside said chambers; means defining orifices between one of said chambers and the other two chambers; a phonographic needle holding means; means to vary the area of said "orifices in response to the movement of said "needle holding-means; and means connected'to said orifice-area-varying means tomaintain the variations in said orifices in phase opposition to -eachother.

'16. A 'microphone comprising -a housing; a body member of insulating material secured within said housing, said body member having three chambers therein; an electrically conductive fluid in said chambers; an electrode in each of said accordingtothe flexing of said diaphragm; a

pivotally mounted actuating member having side portions each in contact "with'said diaphragm "over-one said orifice and adapted to flex said diaphragm-over one said orifice and to relax said diaphragm over the other said orifice when "said actuatingmemberswings on its pivot; and a thin diaphragmstr-ip supported by the actuating member at one edge and adapted to vibrate in response to incoming sound, so asto impart lateral movement to said'actuating member.

'17. A-control devicefor electric circuits -comprising a'body member of insulating material having a plurality of rows of chambers therein, each row havinga center chamber and two side chambers therein, an electrode in each of said chambers, electrolytic fluid in said chambers, a variable' area orifice between said central chamber and each of the two side chambers, and common means to simultaneouslyvary the areas of said orifices in response to externally originating motion.

18. The device'of claim 17 in which the electrode of the center chamber of each row except one is connectedto the electrode of a chamber on one-side of the next adjacent row.

19. A- control device for electric circuits, comprising a body member of insulating material,

having three chambers therein separated by partitions; an electrically conductive fluid in said chambers; an electrode in each of said chambers,

having-terminal connections outside said chambers; a flexible rubber-diaphragm secured around its rim to said body'member, covering an open end of saidchambers, and overlying the partitions between said chambers'so that flexing of said diaphragm .adjacent said partitions 'pro- -vides an. orifice of communication between adjacent chambers. that is varied in size-according ,to the flexing of said diaphragm; and an actuating member, pivotally mounted so that part of it bears on said diaphragm adjacent said partitions, whereby movement of said member on its pivotal mounting will flex said diaphragm and vary the size of orifice between said chambers.

'20. A control device for electric circuits, comprising-a bodymember of insulating material,

having three chambers therein separated by partitions; an electrically conductive fluid in said chambers; an electrode in each of said chambers, having terminal connections outside said cham- ..bers; .adiaphragm secured around its rim to said body member, covering an open end of said -chambers,-and overlying the partitions between said chambers so that movement of the portions -of said diaphragm adjacentsaid partitions providesan orifice of communication between adjacent'chambers that is varied in size according to the movement of said diaphragm portions; and an actuating member, pivotally mounted so that partof it bears on said diaphragm adjacent said partitions, whereby movement of said member on its pivotal-mounting will move said diaphragm portions and vary the size of orifice between said chambers.

21. -'A control device with output multiplication Tor-electric circuits including in combination a body member of insulating material, said body 'member having-a plurality of rows of chambers, eachrow having a center chamber and two side chambers therein; an'electrically conductive-fluid in said chambers; an electrode in each of saidchambers and having terminalconnections outside said chambers, the electrode from the center-chamber of each row'excepting one being electrically connected to the electrode in 'oneside chamber of the succeeding row, all said connected side chambers being on thesame side of said center chambers; a-flexible diaphragm covering all of said chambers and co-operating :with said body member to provide an orifice between the said center chamber in each row and each of the side chambers of said row, the area of each said orifice being varied according to the flexing of said diaphragm; and an actuating r member mounted pivotally and having cross -members at each row that bear on saiddiaphragm adjacent said orifices, whereby movement of said member on its pivotal mounting will cause the diaphragm to be flexed on one side of the center chambers and thereby to narrow the orifice between the center chamber and one of the side chambers and will simultaneously relax the diaphragm on its other side and widen the orifice between said center chamber and the other said side chamben'said rows of chambers thereby serving to amplify and multiply the electrical output which is obtained from the electrode for the center chamber of the last said row.

HARRY C. WARNER.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 203,018 Edison Apr. 30, 1878 1,496,254 Brown June 3, 1924 1,757,775 Latoor May 6, 1930 1,972,578 Wallichs et al Sept. 4, 1934 2,279,815 Dressel Apr. 14, 1942 2,357,026 Scherbatskoy Aug. 29, 1944 2,373,676 Germeshausen Apr. 17, 1945 2,403,696 Warner July 9, 1945 2,407,363 Bussey Sept, 10, 1946 2,491,794 Bachman Dec. 20, 1949 'FOREIGN PATENTS Number Country Date 134,865 Great Britain Nov. 13, 1919 135,157 Great Britain Nov. 13, 1919 385,702 Great Britain Jan. 5, 1933

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