US3193607A

US3193607A - Key switch assembly

Info

Publication number: US3193607A
Application number: US94066A
Authority: US
Inventors: Walter J Anderson
Original assignee: Chicago Musical Instrument Co
Current assignee: Chicago Musical Instrument Co
Priority date: 1961-03-07
Filing date: 1961-03-07
Publication date: 1965-07-06
Anticipated expiration: 1982-07-06

Description

July 6, 1965 w. J. ANDERSON 3,193,607

KEY swIToH ASSEMBLY v Filed March 7, 1961 3 Sheets-Sheet 1 IN VEN TOR. li/fer .l Anw/'salz A TTORNI: YS

July 6, 1965 w. .LANDERSON 3,193,607

' KEY swITcH ASSEMBLY Filed March '7. 1961 3 Sheets-Sheet 2 IN VEN TOR. d Anderson lai/@ @W2 fx/ x A TTORNE YS' 1%/ mm. mm m M ,f y M July 6 l965 w. J. ANDERSON 3,193,607

KEY SWITCH ASSEMBLY Filed March 7, 1961 3 Sheets-Sheet 5 Eid/7@ 104, 7/ 7%* 7/ mmm 9 9% o/ 7/ 7aa"\ l: '50a' 7/ y af INVENTOR.

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A ORNEYS United States Patent O 3,193,607 KEY SWITCH ASSEMBLY Walter J. Anderson, Elgin, Ill., assigner to Chicago Musical Instrument Co., Lincolnwood, Ill., a corporation of Illinois Filed Mar. 7, 1961, Ser. No. 94,066 21 Claims. (Cl. 84-1.l)4)

This invention relates generally to electrical switch structure, and more specifically to an improved key switch assembly for an electrical musical instrument, such as of the electronic type.

Although the principles of the present invention may be included in various devices, a particularly useful application is made in an assembly which forms a part of an electrical musical instrument, either as an attachment accessory, or as an integrated unit in the keyboard of such instrument.

The instant invention is particularly adapted to produce musical chords on such instrument by combining various electrical signals which, when converted to sound, comprise various chords. When such a feature is to be embodied in an electric organ, it is an important objective to minimize the quantity of structure necessary to do a satisfactory job. Accordingly, as will become apparent in reading the following description, the instant invention is readily adapted to cooperate with other structure found in such organs, and to that end employs a minimum of parts and obtains a number of results.

A representative embodiment of the instant invention employs a number of push-button type of keys, each of which is associated with appropriate structure for producing various chords. These chords include a major chord, a dominant seventh chord, a minor chord, a diminished seventh chord, and an augmented chord. Each of these chords includes three or four different notes,`and button keys are provided for producing these chords kin each of the various playing keys which are most commonly used. Where the device is constructed to play in nine different playing keys, such device requires 153 electrical poles.

Accordingly, it is an object of the instant invention to provide a key switch assembly of the type described employing simplified structure.

Another object of the instant invention is to provide a key switch assembly structure wherein certain elements are employed in common with other cooperaing elements to minimize the quantity of structure required.

A still further object of the present invention is to provide a key switch structure which enables the simultaneous closing of a number of circuits.

Yet another object of the present invention is to provide a structure wherein contact wipe is present for maintaining the electrical cleanliness of contacting surfaces.

A still further object of the present invention is to provide a device of the type described wherein individual key elements or push buttons operate with a good feel Yet another object ofthe present invention is to provide a structure wherein a plurality of circuits are simultaneously closed in response to movement of a key for a distance which is only a part of that distance which such key is movable, thereby enabling rapid playing of such device without loss of any musical tone.

A still further object of the present invention is to provide structural details and relationships which minimize the labor and material costs incurred in manufacturing the same.

Many other advantages, features and additional objects of the present invention will become manifest to those versed in the art upon making reference to the detailed description and the accompanying sheets of drawings in which a preferred structural embodiment incorporating the n `ICC principles of the present invention is shown by way of illustrative example.

On the drawings:

FIGURE l is a top plan view of a key switch assembly for a musical instrument provided in accordance with the principles of the present invention, the figure including a schematic diagram illustrating how the invention is ernployed in an lelectrical circuit;

FIGURE 2 is an enlarged schematic perspective diagram of the key switch assembly of FIGURE l, a portion thereof being illustrated nondiagrarnmatically;

FIGURE 3 is an enlarged end elevational view of the key switch assembly shown in FIGURE l;

FIGURE 4 is an enlarged cross-sectional View taken along line IV-IV of FIGURE 1;

FIGURE 5 is an enlarged fragmentary View taken along line V--V of FIGURE 4;

FIGURE 6 is a fragmentary illustration of key structure provided for major chord keys, viewed in a direction normal to the plane of the key element thereof; n

FIGURE 7 is a fragmentary illustration of key structure provided for dominant seventh chord keys, viewed in a direction normal to the plane of the key element thereof;

FIGURE 8 is a fragmentary illustration of key structure provided for minor chord keys, viewed in a direction normal to the plane of the key element thereof;

FIGURE 9 is a fragmentary illustration of key structure provided for diminished seventh chord keys, viewed in a direction normal to the plane of the key element thereof;

FIGURE 10 is a fragmentary illustration of key structure provided for augmented chord keys, viewed in a direction normal to the plane of the key element thereof;

FIGURE l1 is a fragmentary perspective illustration of a modified key-switch structure provided for major chord keys; and

FIGURE l2 is a fragmentary illustration of a modied form of key-switch structure provided for dominant seventh and diminished seventh chord key structure.

As shown on the drawings:

The principles of this invention are particularly useful when embodied in a key switch assembly for an electrical musical instrument, the various switches thereof being adapted to produce chords on such instrument, the same being illustrated in FIGURE l, generally indicated by the numeral 15. The key switch assembly 15 includes, as best seen in FIGURE 3, an insulative frame assembly 16, an electrically conductive collector plate 17, a series of rows of electrically conductive key elements 18-22, nine such rows being illustrated in FIGURE l and one of such rows being illustrated in FIGURE 3, an electrically conductive return spring 23 for each of the key elements lil-22, and a series of elongated resiliently yieldable electric conductors 24-26.

The insulative frame 16 includes an insulative top frame plate 27, an insulative bottom frame plate 28, an insulative front frame plate 29, an insulative rear frame plate 30, and an insulative frame spacer plate 31. The frame plates 27-30 jointly define a hollow boX formation and are held together by a number of brackets 32 to which suc-h plates are attached, as by screws. The spacer plate 31 is disposed in parallel relation to the plates 29 and 3i), and is held in position by a nut and bolt assembly 33 having tubular stand-od elements 34, 35.

The electrically conductive collector plate 17 is secured between the brackets 32 and the bottom frame plate 28, and has a number of upwardly extending integral ears 36 which abut laterally against the plates 29-31 to provide further stability for the same. A number of clips 37 secured to the

plates

29 and 30 provide still further stability for the front and rear frame plates respectively.

Each of the

plates

27 and 28 is provided with a slot which receives and guides opposite ends of each of the key elements 18-22 so that each key element may be moved back and forth nonrotatably in such slots. Each of the key elements is provided with a push button 38 at its upper end, the various push buttons 38 projecting through a suitably apertured cover or template 39 having appropriate identifying markings, such as shown in FG- URE 1. The push buttons 3S may also be marked, if desired. Each of the key elements 18-22 is provided with means identied at 4t) which provides a downwardly direct shoulder, between which shoulder and the plate 17 one of the springs 23 is disposed. Thus, each spring 23 urges one of the key elements in an upward direction as shown, and also electrically connects such key element with the plate 17.. Upward movement of each key element is limited by a pin 41 carried at the lower end of each key element and projecting horizontally therefrom, a felt washer 42 being provided between each pin 41 and the bottom frame plate 28. Downward movement of each key element is arrested when the corresponding key button 38 engages a further felt washer 43 disposed be tween the key button 38 and the upper frame plate 27.

Each of the electrical conductors 24-26 is secured to the insulative frame 16 and is supported thereby. Each of the

conductors

24 and 26 is disposed adjacent to a number of the key elements, and the conductor 25 is disposed adjacent to at least one of the key elements 21. Each of the elongated conductors 24-26 is thus supported in insulated spaced relation to the various key elements 18-22, when such key elements are in their released position as shown in solid lines in FIGURES 3 and 4. The rear end of each of the electrical conductors 24426 is provided with a suitable electric connector 44 of a conventional type which supports that end of the corresponding conductor on the rear plate 30, and which adapts it to be connected to the proper point in the musical instrument circuit described later herein.

The other end of each of the

conductors

24 and 26 is supported, in this embodiment, by the front frame plate 29, while the other end of each of the conductors 25 is supported by the spacer plate 31. The spacer plate V31 is suitably slotted from its upper edge to pass the various conductors 24, and from its lower edge to pass the various conductors 26, as can be seen in FGURE 2. The lower edge of the spacer plate 31, the lower edge of the front frame plate 29, and the upper edge of the front frame plate 29 are each provided with a number of special slots for supporting the other end of the various conductors 24-26. In a preferred embodiment, each of the conductors 24-26 comprises an elongated helical tension spring or spring means having at one end three progressively larger diameters. As seen in FIGURE 5, a iirst or smallest diameter 45 represents the diameter of the conductor throughout substantially all of its length, except at the end being discussed. A second diameter 46 is of intermediate size and a third diameter 47 is somewhat larger. Each of the conductor supporting slots has a width defined by a pair of confronting faces 48 which are spaced apart by a distance which is intermediate the

diameters

45 and 46. At its remote or closed end, the slot is enlarged as at 49 to a size intermediate the diameters 46 and 47, thus deiining a keyhole type of shape. The diameter at 45 is freely received between the faces 48 and the conductor is moved into the slot until the diameter 45 is substantially concentric will the enlargement at 49 which, because of its greater size, freely admits the intermediate diameter 46. Since this diameter is larger than the width 48, that end of the conductor canductor cannot slip out through the slot, and the larger turns 47 serve as a stop against the outside of the front frame plate 29. Since the diameter at 46 is greater than that at 45, it has a lower spring rate so that the turns at 46 expand and tension the conductor, while the turns at 45 remain closed.

FIGURE 6 illustrates one of the key element 18, it being shown in the released position. The key element 18 has electrically conductive engaging arm means 18a and 1gb secured thereto which extend transversely to the conductors 24, and transversely to the direction in which the key element 18 is reciprocable. Depression of the key element 18 effects simultaneous engagement of a plurality of the conductors 24 bythe engaging arm means, thus closing the circuits from each of the conductors 24 so engaged, to the collector plate 17.

FIGURE 7 illustrates the key element 19 which has electrically conductive engaging arm means 19a, 19b, and 19C which also extend transversely to

conductors

24 and 26, and transversely to the direction of key reciprocation. Key elements of this type engage a plurality of conductors simultaneously to close the circuits from them to the plate 17. Where signal frequencies are applied to the conductors 24 as indicated by the notes C, E, and G on FlG-

URES

6 and 7, depression of the key element 18 effects production of a major chord or triad consisting of those notes. It will be noted that the same conductors 24 are engaged by the key element 19 to produce the same major chord, and in addition, since the arm means 19e engages a conductor 26 which is provided with a signal having a frequency corresponding to the note B flat or the dominant seventh note for the musical key of C, depression of the key element 19 produces a dominant seventh chord.

FIGURE 7 also illustrates a feature common to all of the key elements, namely that the engaging arm means come into physical contact with the proper electrical conductors after the key element 19 has been depressed approximately one-half or two-thirds of its available travel. This relationship insures that the chords will be produce when the instrument is played rapidly, without full bottoming ofthe corresponding buttons 38.

The spring 23, when assembled as shown in FIGURE 6, is in a compressed state, and as it is compressed further to the positions shown in FIGURES 7 and 8, the increase in force needed to operate the key element is imperceptible to the user. The force delivered by the spring 23 thus also is somewhat larger than the force required to deflect a group of conductors from their substantially free position, as shown in FIGURE 7, to a deflected position, as shown in FIGURES 4 and 8.

FIGURE 8 shows the structure employed to produce a minor chord, and includes one of the key elements 20. The key element 20 is provided with electrically conductive engaging arm means 20a, 2019, and 20c. The engaging arm 20h is provided with an insulator or insulator sleeve 50 which prevents picking up any signal from the i E spring, as is desired in FIGURES 6 and 7. The er1- gaging arm 20c engages one of the conductors 26 which provides a signal having a frequency corresponding to the pitch of the iiatted third note of the chord. The engaging arm means 20a-20c are otherwise similar to those described above.

FIGURE 9 shows the key structure employed for producing diminished seventh chords. This structure includes the key element 21 which has engaging arm means 21a, 2lb, and 21e. The arm means 21a is engageable with two of the conductors 24, the arm means 2lb is engageable with one of the conductors 25, and the arm means 21e is engageable with one of the conductors 26. These arm means extend transversely to these conductors, transversely to the direction of key element reciprocation, and collectively engage a plural-ity of conductors simultaneously.

FIGURE 10 illustrates the key switch structure employed in this embodiment to produce augmented chords. This structure includes the key element 22 which is provided with engaging arm means 22a, 22b, and 22C. The engaging arm means 22a and 22h engage two of the conductors 24, and the engaging arm means 22e engages one of the conductors 26. The various engaging arm means 22a-22o engage the Various conductors simultaneously.

It will be noted that each of the engaging arm means 19C, 20c, 21e, and 22e` is vertically spaced from the corresponding conducting arm means 19a, 20a, 21a, and 22a respectively. This vertical spacing is substantially the same as that which is provided between the conductors 24 and the

conductors

25, 26. Thus, as best seen in FIG- URES 9 and l0, when the various keys are in the released position as illustrated therein, the actual clearance between the engaging edge of the engaging arms and the cooperating

electrical conductors

24, 25, and 26, is identical, whereby simultaneous engagement or closing of the various circuits occurs.

It will also be noted that the engaging arm means of the various types of key elements illustrated herein each includes a pair of oppositely directed arms which, with the main portion of the various key elements, forms a cross.

All of the conductors 24 are disposed parallel to each other and parallel to each of the rows of tive keys. This relationship is best `seen in FIGURE 2 which illustrates the locations of the various conductors and identities them. In this embodiment, all of the conductors 24 lie in one plane and jointly comprise a first means which is spaced a first distance from the conducting plate 1'7. All major chords or major triads are formed using three consecutive conductors 24. The

additional conductors

25, 26 jointly comprise a second means which is spaced a second distance from the plate 17, which in this embodiment is a lesser distance. The conductors 26 are disposed parallel to each other and thus also lie in a common plane, but they extend transversely to three adjacent rows of five keys. In view of this conductor distribution, it is preferable also to dispose the conductors 25 parallel to each other and in the same plane as the conductors 26 for providing the flatted fifth note to the various diminished seventh chords. The conductors 25 are thus transverse to the appropriate row at a point adjacent to the various diminished seventh key buttons. f

The conductors 26 each provide a dominant seventh note of one of the dominant seventh chords, and may ytherefore: be termed as dominant seventh conductors. However, this is merely a term of reference, since the same conductor provides three other notes for three other chords. This set of conductors is also employed to provide the flatted third note of the minor chord and the fla-tted third note of the diminished seventh chord, as well as the raised fifth of the augmented chords. Therefore, this conductor may also be termed as a flatted third conductor and as an augmented fifth conductor.

Referring to FIGURE 2, it will be noted that all of the C chords are disposed in a row, that all of the G chords are disposed in a row, etc. It will also be noted that all of the major chords from each row are aligned, that all 'of the dominant seventh chord buttons of each row are aligned, etc. Beginning with the key of C row, the next 4increase one sharp for each row to the right, and by one tiat for each row to the left. `would ordinarily prefer to play on a conventional key- Most t-rained musicians board, but the chord key switch assembly of this invention is provided primarily forA the amateurs and novices.

,It is thus practical to omit structure for produc-ing chords Afor playing keys having tive, six, or seven Sharps or flats,

such being ordinarily beyond the scope of the musician who would use this invention to greatest advantage. Moreover, only a very small fraction of music which is written is composed in those difficult keys. In any event,

`it will become readily apparent to one who has studied this description that the pattern established in FIGURE 2 may be extended or contracted at either end to adapt a particular embodiment to the level of music or musicianship desired.

To produce a C major chord, it is necessary to combine signal frequencies of the C note, the E note, and the G note. The C note is the root note, the E note is referred to as a third note, and the G note is referred to as the fth or fifth-note. Thus, as best seen in FIGURES 2 and 6, one of the conductors 24 extends to the left of the C major button to provide :a signal whose frequency is that of the C note, and two additional conductors 24 extend to the right of the C major button to provide the third and fifth note frequencies. This chord is then produced by depression of that button, the structure utilized being shown in FIGURE 6. These same three conductors extend in the same manner in the `same relative position adjacent to all of the key elements in the C row. The C or root conductor is engaged by all of these key elements, the E or third yconductor is engaged by the key elements of the major, dominant seventh, and augmented chords, and the G conductor is engaged -by the major, dominant seventh, and minor chord-s. Since the key element of the minor chord must engage the fifth note conductor, and not the third note conductor, insulation means are provided, as explained, to avoid including signal `from the third note conductor. Thus, it will be readily understood that the engaging arm means 2Gb may be appropriately shaped so that the insulator -comprises an air gap between the engaging arm 2012 and the third note conductor.

With the keyboard arranged in this manner, it will be noted that the fth note of each chord is the root note of the next adjacent chord to the right. This is true for each pair of adjacent rows. Thus the G note or fifth note conductor for the C row is also engaged by all tive of the key elements ofthe G note row, since it is the root note thereof. Thus the C, G, D, etc. conductors `24 are each engaged by eight key elements, and the third note conductors 24, such as E, B, Fit, Cit, etc. are electrically engaged by only four key elements. Thus, each key element 118 is engageable with a group of three adjacent conductors 24 which define a major triad, consisting of the root, third, and fifth notes, and the other four key elements in the same row engage the same root and certain other of these three conductors. Thus, also, the fifth note yconductor of each row is the root note conductor for all of the chords of the next row to the right, whereby two adjacent rows employ the same conductor 24.

It is to be noted that the third note conductor of each major chord is also engaged by the key element 21 of the adjacent row to the right so that the conductor which provides the third of the major, dominant seventh, and augmented chords al-so provides the diminished seventh note of a chord whose root is a fifth higher. Thus the third and fifth conductors of the C major chord are also utilized as the root and diminished seventh 4conductors of the G diminished seventh chord. Thus the third note condu-ctors 24 are each electrically engaged by not only the three previously described key elements, but also by a fourth key element in the adjacent row. Each dominant'seventh note conductor 26 is used to provide the dominant seventh note in one row, the atted third notes of the minor cho-rd and the diminished seventh chord in` the next row to the right, and the raised fifth of the augmented chord of the still next row to the right, each row to the right 'being a fifth higher than the preceding row. A diminished chord, without the seventh note, can be provided by shortening the length of the engaging arm means 21a so that it does not engage that conductor 24 which provides the diminished seventh note. However, it is preferred to construct the device as shown and described since the diminished seventh chord is a particularly beautiful chord.

As a musician gains experience with this device, he will ldiscover that certain combinations of buttons may be simultaneously depressed to obtain further chord combinations which .are particularly beautiful. In each of these, a

portion of the chord may be added or removed without disrupting the rest of the chord. To illustrate, assume that the C major chord button has been depressed, thus simultaneously effecting the sounding of C, E, and G. With this arcano? chord being held, the C dominant seventh chord button may also be pressed, thus adding the ydominant seventh note to the chord, which note may be removed and added lat will Without disturbing the production of the tone-s cfomprising the major chord. This freedom from disturance is brought about the nature of the structure employed. It can be seen in AFIGURE 4 that when any button is fully depressed, the various conductors engaged by it will deflect fully only at that particular button, and will be displaced only partially adjacent to any other button. When -such other `button is depressed which .is to come in contact with one or more of the same conductors, there is still some travel `or deflection possible also at that `other key element, and thereafter, either button may be raised without disturbing the continuities present at the other button which engages the same conductor.

A further unusual or unexpected combination may be achieved by first depressing one of the major chord buttons, lor its dominant seventh chord button, and thereafter or simultaneously therewith depressing the minor chord button of the next row to the right, whose root note is a fifth higher, to thereby add the ninth note to the dominant seventh chord, or to add the dominant seventh note and the ninth. note to the major chord. The resulting livetone chord is beautiful, unusual, and often awkward to play with one hand `on a conventional keyboard, due to the spacing of keys. The addition of a ninth in that manner presupposes that the device as a whole will be used with signal lsources of suitable frequencies. In this example also, the conductors which are engaged by both of the key elements involved, will yield initially, :and will yield further in response to actuation of the second key.

The instant device can be used to advantage when connected to twelve suitable tone generators or signal sources of various frequencies represented by a chromatic scale. Each signal source is schematically indicated at 51 and may comprisev a low impedance source. Each signal source 51 is connected through a current limiting resistor 52 to Ian appropriate terminal -on the device 15 by means of a number yof wires which are -collectively brought to- `gether as a cable 53, wherein the individual wire-s are insulated from each other. Each wire is then connected to terminals in accordance with markings indicated on FIG- URE 2. Where only twelve signal sources are employed, all of the conductors 24-26 having the same note, are connected together as shown. By this structure, certain chords will be inverted. However, if it is desired to avoid inversion, -additional signal sources 51 may be employed (which are already present in most organs), each being connected to the appropriate conductors 24-26 directly, the various jumper wires 54 then being omitted.

The conductive plate 17 is provided with a terminal 55 to which a wire 56 is connected, which is maintained above ground by a resistor 7. The wire 56 is connected through a coupling capacitor 58 to a junction point 59 which is common with one side of a number of tab switches or stops 60. Each of the switches 60 controls various paths that the signal may take through a series of voicing circuits 61 of a known type, the output of which is amplilied as at 62 for being converted into sound by a speaker 63. Where the instant invention is used as an attachment, or in combination with other manuals for producing similar pitched notes, signals from such other manual may be brought into the circuit by a lead wire 64 communicating with the junction point 59.

A typical value for the resistor 52 is 800,000 ohms, for resistor 57 is 200,000 ohms, and for the capacitor 58 is .02 mfd.

It is now evident that the disclosed embodiment may be used to combine twelve signals in forty-five different ways, that the number of signals to be combined and that the number of ways of combining them can be expanded, that the signals which are combined by the depression of any key button are each simultaneously initiated, that the instant embodiment discloses 153 separate switches each of which has a rubbing action with the various key elements for maintaining cleanliness thereof, that the various key buttons all have a uniform feel as between each other and as each button is deected, and that the various buttons can be played rapidly with the resulting chords produced without full displacement of the buttons.

Referring now to FIGURE l1, there is illustrated an alternate form of conductors. A pair of spaced insulative frame plates 66 supports a plurality of conductors 67 of the solid type, each of which is fitted with a resilient spring 68 at each end thereof, the spring 68 at one end of each of the conductors 67 being adapted to be connected to a suitable source of signal, as described before. Displacement of the key element 18 effects an engagement between the engaging arm means 18a, 1811 and the various conductors 67. In response to such engagement, the conductive spring means 68 thereof yield to permit additional displacement of the key element 18.

FIGURE 12 illustrates a further modification which includes a number of rigidly supported rigid conductors 69, shown in cross-section, and supported by a frame structure (not shown) similar to that disclosed and described, which reciprocably supports a key element 70. The key element 70 is provided with a number of arms 70a, each of which has a spring or elongated resiliently yieldable electrical conductor 71 secured thereto. When the key element 70 is displaced, the various springs 71 will yield after they have been engaged, to thereby permit further displacement of the key element 70.

In FIGURE 2, it will be noted that one ofthe shorter conductors 25 is disopsed between each adjacent pair of the longer conductors 2d, the endmost conductors 26 being abbreviated in length and supported by the spacer plate 31. In order to adequately describe the conductor 25 in relation to FIGURES 3 and 4, reference to the shortened E conductor 26 has been omitted above. The appearance of the shortened E conductor 26 is identical to the illustrated conductor 25.

Although various minor modifications might be suggested by those versed in the art, it should be understood that I wish to embody within the scope of the patent warranted hereon all such embodiments as reasonably and prpperly come within the scope of my contribution to the ar I claim as my invention:

1. A key-switch comprising in combination: an electrically conducive plate; an electrically conductive key element reciprocably supported in electrical contact with said plate; a pair of separate electrical conductors disposed adjacent to but spaced different distances from said key element and electrically insulated therefrom and from each other; and an electrically conductive arm electrically conductively secured to said conductive key element and extending therefrom transversely to said conductors and transversely to the direction in which said key element is reciprocable and selectively engageable simultaneously with both said conductors in response to reciprocation of said key element; and an insulator engageable with both said arm and that one of said conductors which is nearer to said key element in a manner to preclude electrical continuity therebetween during said engagement.

2. A key-switch comprising in combination: an electrically conductive apertured plate; an electrically conductive key element reciprocably supported in electrical contact with said plate and extending through the aperture thereof: an elongated helical electrically conductive extension spring Contact rigidly supported at both its ends and disposed adjacent to said key element and electrically insulated therefrom; and an electrically conductive engaging arm electrically conductively secured to said key element and extending therefrom transversely to said spring contact and transversely to the direction in which said key element is reciprocable and selectively engageable with said spring contact in response to reciprocation of said key element, said spring contact being yieldable intermediate its ends in response to being engaged by said engaging arm.

3. A key-switch comprising in combination: an insulative frame having a slot; a separate electrically conductive apertured plate supported by said frame; an electrically conductive key element reciprocably supported by said insulative frame in electrical contact with said plate and extending through the aperture thereof; and an electrical contact comprising an elongated helical conductive extension spring supported at both ends by said frame and disposed adjacent to and insulated from said reciprocable key element; said key element having an engaging arm extending therefrom transversely to said spring contact and transversely to the direction in which said key element is reciprocable, and engageable with said spring contact, said arm being electrically coupled through said conductive key element to said conductive plate; said helical contact spring having wire turns of three progressively larger diameters all at one end thereof; said frame slot being of a width intermediate the two smaller turn diameters receptive of only the smallest diameter and terminating at its closed end in an opening of a size intermediate the two larger turn diameters and receiving and supporting the intermediate diameter size turn.

4. A key-switch comprising in combination: an insulative frame; a separate electrically conductive apertured plate supported by said frame; an electrically conductive key element reciprocably supported by said insulative frame in electrical contact with said plate and extending through the aperture thereof; and an electrical contact comprising an elongated helical conductive extension spring supported at both ends by said frame and disposed adjacent to and insulated from said reciprocable key element; said key element having an engaging arm, extending therefrom transversely to said spring contact and transversely to the direction in which said key element is reciprocable, and engageable with said spring contact, said arm being electrically coupled through said conductive key element to said conductive plate.

5. In a switch assembly having an electrical helical contact spring, the improvement comprising: a series of wire turns all at one end of the electrical contact spring of three progressively larger diameters; and a support member having a slot of a width intermediate the two smaller turn diameters receptive of only the smallest diameter, and terminating at its closed end in an opening of a size intermediate the two larger turn diameters and receiving and supporting the intermediate diameter size turns.

6. A key-switch assembly for producing chords in an electrical musical instrument, comprising in combination: an electrically conductive apertured plate; a series of electrically conductive key elements, each reciprocably supported in electrical contact with said plate and each extending through a separate aperture therein; a series of more than three electrical conductors lying in a plane parallel to said plate and extending between said key elements and electrically insulated therefrom, said conductors being adapted to be connected to variousfrequency signal sources; and electrically conductive engaging arm means secured to each of said key elements and electrically coupled therethrough to said plate and extending therefrom transversely to said conductors and transversely to the direction in which each key element is reciprocable for engagement with a plurality of said conductors in response to reciprocation of one of said key elements.

7. In a keyed electrical musical instrument having a plurality of signal sources whose frequencies severally comprise major triads of root, third, and fifth notes, the

improvement in combination therewith of: an electrical- ,ly conductive apertured plate; a series of electrically con- `ductive key elements, each reciprocably supported in electrical contact with said plate and each Vextending through a separate aperture therein; a series of electrical conductors lying in a plane parallelV to said plate and respectively connected to said signal sources and extending between said key elements and electrically insulated therefrom; and electrically conductive engaging arm means for each of said key elements and secured thereto and electrically coupled therethrough to said plate, the arm means of each of said key elements extending therefrom transversely to three of said conductors whose frequencies comprise one major triad, and transversely to the direction in which the key element is reciprocable for engagement with said three conductors in response to reciprocation ofthe key element; the conductor whose signal source has the fifth note frequency of said one major triad also being engageable by the engaging arm means of another one of said key elements where its frequency comprises the root note signal of a different chord.

S. In a keyed electrical musical instrument having a plurality of signal sources whose frequencies severally comprise major triads of root, third, and fifth notes, the improvement.inicombination therewith of: an electrically conductive apertured plate; a series of electrically conl ductive key elements, each reciprocably supported in electrical contact with said plate and each extending through a separate aperture therein; a series of electrical conductors lying in a plane parallel to said plate and respectively connected to said signal sources and extending between said key elements and electrically insulated therefrom; and electrically conductive engaging arm means for each of said key elements and secured thereto and electrically coupled therethrough to said plate, the arm means of each of said key elements extending therefrom transversey `to three of said conductors Whose frequencies comprise one major triad, and transversely to the direction in which the key element is reciprocable for engagement with said three conductors in response to reciprocation of the key element; those of said three conductors, whose signal source frequency appears in another chord of the same root note, being also engageable by the engaging arm means of another one of said key elements.

9. ln a keyed electrical musical instrument having a plurality of signal sources whose frequencies jointly comprise a musical scale, the improvement in combination therewith of: an electrically conductive apertured plate; a series of electrically conductive key elements, each re- Vciprocably supported in electrical contact with said plate and each extending through a separate aperture therein; a series of electrical conductors lying in a plane parallel to said plate and respectively connected to said signal sources and extending between said key elements and electrically insulated therefrom; and electrically conductive engaging arm means for each of said key elements and secured thereto and electrically coupled therethrough to said plate, the arm means of each of said key elements extending therefrom transversely to three of said conductors whose frequencies comprise a chord, and transversely to the direction in which the key element is reciprocable for engagement with said three conductors in response to reciprocation of the key element; one of said three conductors being engageable by the arm means of a plurality of said chord-producing key elements which engage a plurality of root note conductors.

10. In a keyed electrical musical instrument having a plurality of signal sources whose frequencies jointly comprise a musical scale, the improvement in combination therewith of: an electrically conductive apertured plate; a series of electrically conductive key elements, each reciprocably supported in electrical contact with said plate and each extending through a separate aperture therein; a series of electrical conductors lying in a plane parallel to said plate and respectively connected to said signal sources and extending between said key elements and electrically insulated therefrom; and electrically conduclll tive engaging arm means for each of said key elements and secured thereto and electrically coupled therethrough to said plate, the arm means of each of said key elements extending therefrom transversely to three of said conductors whose frequencies comprise a chord, and transversely to the direction in which :the key element is reciprocable for engagement with said three conductors in response to reciprocation of the key element; one of said conductors being engageable by said arm means of four of said key elements to provide the iiatted third note of both the minor chord and the diminished seventh chord of a certain root note, the dominant seventh note of the dominant seventh chord whose root note is a fifth below said certain root note, and the raised fifth note of the augmented chord whose root note is a fifth above said certain root note.

11. In a keyed electrical musical instrument having a plurality of signal sources whose frequencies jointly comprise a musical scale, the improvement in combination therewith of: an electrically conductive apertured plate; a series of electrically conductive key elements, each reciprocably supported in electrical Contact with said plate and each extending through a separate aperture therein; a series of electrical conductors lying in a plane parallel to said plate and respectively connected to said signal sources and extending between said key elements and electrically insulated therefrom; and electrically conduce tive engaging arm means for each of said key elements and secured thereto and electrically coupled therethrough to said plate, the arm means of each of said key elements extending therefrom transversely to three of said conductors whose frequencies comprise a chord, and transversely to the direction in which the key element is reciprocable for engagement with said three conductors in response to reciprocation of the key element; one of said conductors being engageable by said arm means of said key elements to provide at least two notes from the group consisting of the flatted third note of either the minor chord or of the diminished seventh chord of a certain root note, the dominant seventh note of the dominant seventh chord whose root note is a fifth below said certain root note, and the raised fifth note of the augmented chord Whose root note is a fifth above said certain root note.

12. In a keyed electrical musical instrument having a plurality of signal sources whose frequencies severally comprise major triads of root, third, and fifth notes, the improvement in combination therewith of: an electrically conductive apertured plate; a series of electrically conductive key elements, each reciprocably supported in electrical contact with said plate and each extending through a separate aperture therein; a series ofelectrical conductors lying in a plane parallel to said plate and respectively connected to said signal sources and extending between said key elements and electrically insulated therefrom; land -electrically `conductive engaging arm means for each of said key elements and secured thereto and electrically coupled therethrough to said plate, the arm means of each of said key elements extending therefrom transversely to three cf said conductors whose frequencies comprise one major triad, and transversely to the directionfin which the key element is reciprocable for engagement with said three conductors in response to reciprocation of the key element; the conductor whose signal source has the fifth note frequency of said one major triad also being engageable by the engaging arm means of another one of said key elements where its frequency comprises the root note signal of a different chord, said another one of said key elements also being engageable with other of said conductors whose signal frequencies comprise the flatted third and iiatted fifth notes to render said different chord a diminished chord.

13. In a keyed electrical musical instrument having a plurality of signal sources whose frequencies severally comprise major triads of root, third, and fifth notes, the improvement in combination therewith of: an electrically conductive apertured plate; a series of electrically conductive key elements, each reciprocably supported in electrical contact with said plate and each extending through a separate aperture therein; a series of electrical conductors lying in a plane parallel to said plate and respectively connected to said signal sources and extending between said key elements and electrically insulated therefrom; and electrically conductive engaging arm means for each of said key elements and secured thereto and electrically coupled therethrough to said plate, the arm means of each of said key elements extending therefrom transversely to three of said conductors whose frequencies comprise one major triad, and transversely to the direction in which the key element is reciprocable for engagement with said three conductors in response to reciprocation of the key element; the conductors Whose signal sources have the fifth and third note frequencies of said one major triad also being engageable by the engaging arm means of another one of said key elements to provide the root note and the diminished seventh note signals of a different chord, said another one of said key elements also being engageable with other of said conductors whose signal frequencies comprise the iiatted third and flatted fifth notes to render said different chord a diminished seventh chord.

ld. In a keyed electrical musical instrument having a plurality of signal sources whose frequencies severally comprise major triads of root, third, and fifth notes, the improvement in combination therewith of: an electrically conductive apertured plate; a series of electrically conductive key elements, each reciprocably supported in electrical contact with said plate and each extending through a separate aperture therein; a series of electrical conductors lying in a plane parallel to said plate and respectively connected to said signal sources and extending between said key elements and electrically insulated therefrom; and electrically conductive engaging arm means for each of said key elements and secured thereto and electrically coupled therethrough to said plate, the arm means of each of said key elements extending therefrom transversely to three of said conductors whose frequencies comprise one major triad, and transversely to the direction in which the key element is reciprocable for engagement With said three conductors in response to reciprocation of the key element; each of said three conductors being also engageable by the engaging arm means of a further one of said key elements, said further one of said key elements also being -engageable with another conductor providing a signal frequency comprising the dominant seventh note for also providing a dominant seventh chord.

l5. In a keyed electrical musical instrument having a plurality of signal sources whose frequencies severally comprise major triads of root, third, and fifth notes, the improvement in combination therewith of: an electrically conductive apertured plate; a series of electrically conductive key elements, each reciprocably supported in electrical contact with said plate andreach extending through a separate aperture therein; a series of elongated normally straight flexible stretchable electrical conductors supp0rted at both ends and normally lying in a plane parallel to said plate and respectively connected to said signal sources and extending between said key elements and electrically insulated therefrom; and electrically conductive engaging arm means for each of said key elements and secured thereto and electrically coupled therethrough to said plate, the arm means of each of said key elements extending therefrom transversely to three of said conductors whose frequencies comprise one major triad, and transversely to the direction in which the key element is reciprocable for engagement with said three conductors in response to reciprocation of the key element, each of said three conductors being also engageable by the engaging arm means of a further one of said key elements, said further one of said key elements also being engageable with another conductor providing a signal frequency comprising the dominant seventh note for thereby also providing a dominant seventh chord; said flexible stretchable conductors being deflectable in response to said engagement effected by reciprocation of a iirst of said key elements, and a portion thereof being deiiectable an additional amount in response to being simultaneously engaged by the arm means of a second of said key elements, whereby the dominant seventh note may be added to and removed from a major triad chord while said triad chord is continually maintained.

16. In a keyed electrical musical instrument having a plurality of signal sources whose frequencies severally comprise major triads of root, third, and fifth notes, the improvement in combination therewith of: an electrical- 1y conductive apertured plate; a series of electrically conductive key elements, each reciprocably supported in electrical contact with said plate and each extending through a separate aperture therein; a series of electrical conductors lying in a plane parallel to said plate and respectively connected to said signal sources and extending between said key elements and electrically insulated therefrom; said conductors being so arranged that groups of three adjacent conductors have signal frequencies which comprise the root, third, and fifth notes of a major triad, the fifth note conductors of a plurality of said groups being the root note conductors of successive adjacent triads; and electrically conductive engaging arm means for each of said key elements and secured thereto and electrically coupled therethrough to said plate, the arm means of each of said key elementsV extending therefrom transvcrselyto one of said conductor groups and transversely to the direction in which the key element is reciprocable for engagement with said one conductor group in response to reciprocation of the key element.

17. In a keyed electrical musical instrument having a plurality of signal sources whose frequencies severally comprise major triads of root, third, and fifth notes, the improvement in combination therewith of: an electrically conductive apertured plate; a series of electrically conductive key elements arranged in a plurality of rows, each reciprocably supported in electrical contact with said plate and each extending through a separate aperture therein; a series of electrical conductors lying parallel to said rows in a plane parallel to said plate and respectively connected to said signal sources and extending between said key elements and electrically insulated therefrom; said conductors being so arranged that groups of three adjacent conductors have signal frequencies which comprise the root, third, and fifth notes of a major triad, the fifth note conductors of a plurality of said groups being the root note conductors of successive adjacent triads; electrically conductive engaging arm means for each of said key elements in said rows and secured thereto and electrically coupled therethrough to said plate, the arm means of each of said key elements extending therefrom transversely to said conductors and transversely to the direction in which the key element is reciprocable; the arm means of one of said key elements of each row being engageable with one of sai-d conductor groups respectively; and additional elongated electrical conductors disposed adjacent to other key elements in each of said rows and electrically insulated therefrom, said additional conductors having other signal frequencies; said other key elements in each of said rows being engageable through its arm means with at least one of said additional conductors and at least one conductor of said one group in response to reciprocation thereof.

18. In a keyed electrical musical instrument having a plurality of signal sources whose frequencies severally comprise major triads of root, third, and fifth notes, the improvement in combination therewith of: an electrically conductive apertured plate; a series of electrically conductive key elements arranged in a plurality of rows, each reciprocably supported in electrical Contact with said plate and each extending through a separate aperture therein; a series of electrical conductors lying parallel to electrically conductive engaging arm means for each ofI said key elements in said rows and secured thereto and electrically coupled therethrough to said plate, the arm means of each of said key elements extending therefrom transversely to said conductors and transversely to the direction in which the key element is reciprocable; the arm means of one of said key elements of each row being engageable with one of said conductor groups respectively; and additional elongated electrical conductors disposed adjacent to other key elements in each of said rows and electrically insulated therefrom, certain of said additional conductors being disposed parallel to each other and extending in spaced transverserelation to three of said conductor groups, said addition conductors having other signal frequencies; said other key elements in each of said rows being engageable through its arm means with at least one of said additional conductors and at least one conductor of said one group in response to reciprocation thereof; each of said certain additional conductors being engaged by the arm means of at least one of said other key elements in each of three adjacent rows.

` 19. A key-switch assembly for producing chords in an electrical musical instrument, comprising in combination: an electrically conductive apertured plate; a series of electrically conductive key elements, each reciprocably supported in electrical contact with said plate and each extending through a separate aperture therein; a iirst series of more than three electrical conductors lying parallel to each other in a plane parallel to said plate, and a second series of more than three electrical conductors lying parallel to each other in a plane parallel to said plate and each extending in spaced transverse relation to said first series of conductors, said conductors extending between said key elements and electrically insulated therefrom, said conductors being adapted to be connected to various-frequency signal sources; and electrically conductive engaging arm means secured to each of said key elements and electrically coupled therethrough to said plate and extending therefrom transversely to said conductors and transversely to the direction in which each key element is reciprocable for engagement with a plurality of said conductors in response to reciprocation of one of said key elements.

20. In a keyed electrical musical instrument having a plurality of signal sources Whose frequencies severally comprise major triads of root, third, and fifth notes, the improvement in combination therewith of: an electrically conductive apertured plate; a series of electrically conductive key element-s arranged in a plurality of rows, each reciprocably supported in electrical contact with said plate and each extending through a separate aperture therein; a series of electrical conductors lying parallel to said rows in a plane parallel to said plate and respectively connected to said signal sources and extending between said key elements and electrically insulated therefrom; said conductors being so arranged that groups of three adjacent conductors have signal frequencies which comprise the root, third, and fifth notes of a major triad, the fifth note conductors of a plurality of said groups being the root note conductors of successive adjacent triads; electrically conductive engaging arm means for each of said key elements in said rows and secured thereto and electrically coupled therethrough to said plate, the arm means of each of said key elements extending therefrom transversely to said conductors and transversely to the direction in which the key element is reciprocable; the arm means of one of said key elements of each row areasp? being engageable with one of said conductor groups respectively; and additional elongated electrical conductors disposed adjacent to other key elements in each of said rows and electrically insulated therefrom, certain of said additional conductors being disposed parallel to each other and extending in spaced transverse relation to at least two of said conductor groups, said additional conductors having other signal frequencies with said certain additional conductors providing the dominant seventh note frequency; said other key elements in each of said rows being engageable through its arm means with at least-one of said additional conductors and at least one conductor of said one group in response to reciprocation thereof, one of said other key elements in one row being engageable through its arm means with the conductors of said one group and with the corresponding one of said certain additional conductors to provide a dominant seventh chord, one of said other key elements in an adjacent row being engageable through its arm means with the root and fth note conductors of its row and with said one of said certain additional conductors to provide a minor chord, and said one of said other key elements being selectively simultaneously reciprocable with said one other key element to add a ninth note to said dominant seventh chord.

21. A key-switch comprising in combination: an electrically conductive apertured plate; a reciprocably-supported electrically-conductive key element extending through the plate aperture; an electrically conductive spring surrounding one end of said key element and effecting electrical continuity between said key element and said plate, and continually urging said key element in one direction; an elongated helical electrically conductive extension spring contact rigidly supported at both its ends and disposed adjacent to said key element and electrically in- 1? sulated therefrom; and an electrically conductive engaging arm secured to said key element and electrically coupled through said spring to said plate and extending from said key element transversely to said spring contact and transversely to the direction in which said key element is reciprocable and selectively engageable with said spring contact in response to reciprocation of said key element in the opposite direction, said spring contact being yieldable intermediate its ends in response to being engaged by said engaging arm, said spring applying a force to said key element which is somewhat greater than the force by which said spring contact resists yielding in response to said engagement and which provides the feel to manual movement of said key element.

References Cited by the Examiner UNITED S ATES PATENTS GEORGE N. WESTBY, Primary Examiner.

LAWRENCE V. EFNER, ARNOLD RUEGG,

. Examiners.

Claims

1. A KEY SWITCH COMPRISING IN COMBINATION: AN ELECTRICALLY CONDUCTIVE PLATE; AN ELECTRICAL CONDUCTIVE KEY ELEMENT RECIPROCABLY SUPPORTED IN ELECTRICAL CONTACT WITH SAID PLATE; A PAIR OF SEPARATE ELECTRICAL CONDUCTORS DISPOSED ADJACENT TO BUT SPACED DIFFERENT DISTANCES FROM SAID KEY ELEMENT AND ELECTRICALLY INSULATED THEREFROM AND FROM EACH OTHER; AND AN ELECTRICALLY CONDUCTIVE ARM ELECTRICALLY CONDUCTIVELY SECURED TO SAID CONDUCTIVE KEY ELEMENT AND EXTENDING THEREFROM TRANSVERSELY TO SAID CONDUCTORS AND TRANSVERSELY TO THE DIRECTION IN WHICH SAID KEY ELEMENT IS RECIPROCABLE AND SELECTIVELY ENGAGEABLE SIMULTANEOUSLY WITH BOTH SAID CONDUCTORS IN RESPONSE TO RECIPROCATION OF SAID KEY ELEMENT; AND AN INSULATOR ENGAGEABLE WITH BOTH SAID ARM AND THAT ONE OF SAID CONDUCTORS WHICH IS NEARER TO SAID KEY ELEMENT IN A MANNER TO PRECLUDE ELECTRICAL CONTINUITY THEREBETWEEN DURING SAID ENGAGEMENT.