US3657460A - Organ keyboard switching system - Google Patents

Organ keyboard switching system Download PDF

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Publication number
US3657460A
US3657460A US108841A US3657460DA US3657460A US 3657460 A US3657460 A US 3657460A US 108841 A US108841 A US 108841A US 3657460D A US3657460D A US 3657460DA US 3657460 A US3657460 A US 3657460A
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US
United States
Prior art keywords
strip
row
spaced
contacts
contact
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US108841A
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English (en)
Inventor
Stanley Cutler
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Mattel Inc
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Mattel Inc
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Publication date
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Publication of US3657460A publication Critical patent/US3657460A/en
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Classifications

    • G—PHYSICS
    • G10—MUSICAL INSTRUMENTS; ACOUSTICS
    • G10H—ELECTROPHONIC MUSICAL INSTRUMENTS; INSTRUMENTS IN WHICH THE TONES ARE GENERATED BY ELECTROMECHANICAL MEANS OR ELECTRONIC GENERATORS, OR IN WHICH THE TONES ARE SYNTHESISED FROM A DATA STORE
    • G10H1/00—Details of electrophonic musical instruments
    • G10H1/32—Constructional details
    • G10H1/34—Switch arrangements, e.g. keyboards or mechanical switches specially adapted for electrophonic musical instruments
    • G10H1/344—Structural association with individual keys
    • G—PHYSICS
    • G10—MUSICAL INSTRUMENTS; ACOUSTICS
    • G10H—ELECTROPHONIC MUSICAL INSTRUMENTS; INSTRUMENTS IN WHICH THE TONES ARE GENERATED BY ELECTROMECHANICAL MEANS OR ELECTRONIC GENERATORS, OR IN WHICH THE TONES ARE SYNTHESISED FROM A DATA STORE
    • G10H2220/00—Input/output interfacing specifically adapted for electrophonic musical tools or instruments
    • G10H2220/155—User input interfaces for electrophonic musical instruments
    • G10H2220/265—Key design details; Special characteristics of individual keys of a keyboard; Key-like musical input devices, e.g. finger sensors, pedals, potentiometers, selectors
    • G10H2220/275—Switching mechanism or sensor details of individual keys, e.g. details of key contacts, hall effect or piezoelectric sensors used for key position or movement sensing purposes; Mounting thereof
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S84/00—Music
    • Y10S84/07—Electric key switch structure

Definitions

  • ABSTRACT A switch assembly operated by the keys of an electronic organ [52] US. Cl. ..84/ 1.01, 84/ l .07, 84/DlG. 7, to connect different tone generators to the loudspeaker, which 200/ 166 J is simple and which minimizes mechanical and electrical [51] Int. Cl. ..Gl0h 1/00 noises during closing of the switches.
  • the assembly includes a Field Of Search row of resilient switch members connected to the loudspeaker DIG. 333/154, ZOO/166 T and positioned to be individually deflected up against a contact assembly.
  • the contact assembly includes a a circuit board References Cited with numerous conductive pads arranged in a row above the UNITED STATES PATENTS row of switch members, a pair of insulating spacer strips extendmg along either s1de of the row of pads, and an lnter- 2,959,693 11/1960 mediate strip of conductive plastic fastened to the spacer 2,575,230 1 l/ 1951 strips.
  • a corresponding switch 0 8/1958 member is deflected upwardly to press a region of the plastic 3,474,132 1969 strip against a conductive pad.
  • One type of switching apparatus includes a row of resilient contact members which are deflected upwardly to contact a bus bar, each switch member connected to a different tone generator and the bus bar being connected to the speaker assembly.
  • the bus bar can be constructed of copper or other metal, or of a conductive plastic such as polyvinylchloride (PVC) material impregnated with carbon to make it partially conductive.
  • PVC polyvinylchloride
  • An object of the present invention is to provide a switching arrangement for electronic organs, which is economical to produce and install.
  • Another object is to provide a switching arrangement for electronic organs, which minimizes noises which can occur during the closing of switches.
  • a switch assembly for electronic organs, which is simple and economical to construct and install and which minimizes noises which can occur during operation of the switches.
  • the assembly includes a row of resilient switch members which can be upwardly deflected against a contact assembly by operation of the organ keys.
  • the contact assembly includes a circuit board with numerous conductive pads arranged in a row above the row of switch members.
  • a pair of insulating spacer members extend along either side of the row of circuit board pads, and an intennediate strip constructed of flexible conductive plastic is fastened to the spacer strips so it lies spaced slightly below the row of pads.
  • the use of a circuit board with numerous conductive pads minimizes the amount of labor required in making electrical connections.
  • the circuit board can be mass produced at low cost, and can be made to terminate in a row of strips so that it can be installed by plugging one end of it into a connector in the organ.
  • the use of a flexible intermediate strip reduces mechanical noise because much of the kinetic energy of the upwardly moving switch member is absorbed in deflecting the strip, and because the strip can dampen vibrations of the switch member before contact is made with a circuit board pad. Electrical noise in the form of clicks or pops is minimized where an intermediate strip is used which undergoes a decrease in resistance during the first portion of compression thereof, as can be the case of a strip constructed of polyvinylchloride impregnated with carbon.
  • the intermediate strip can be connected through a capacitor to ground so that it is charged up to any DC bias of the tone generators when the first few notes are played on the organ. Thereafter, transients due to DC bias of the tone generator are substantially eliminated.
  • FIG. 1 is a partial perspective view of an organ with a keyboard switching assembly constructed in accordance with the present invention
  • FIG. 2 is a sectional side view of the apparatus of FIG. 1;
  • FIG. 2a is a view similar to FIG. 2, but with the switch in a closed state
  • FIG. 3 is a partial schematic view of the apparatus of FIG. 1;
  • FIG. 4 is a partial bottom view of the circuit board of the apparatus of FIG. 1.
  • FIG. 1 illustrates an organ constructed in accordance with the invention, which includes tone generator apparatus 10 for generating electrical signals representing musical tones, speaker apparatus 12 for converting the signals to audible sounds, and switching apparatus 14 for enabling a musician to select the tones to be played, or sounded.
  • the tone generator apparatus 10 includes a rotatable optical disc record 16 which has numerous concentric tracks 18 defined by the transparent regions between opaque borders.
  • a lamp 20 directs light through the tracks 18 as the disc rotates, and a series of photocells 22 sense the light which passes through the tracks.
  • the photocells may be considered as tone generators, inasmuch as they generate electrical signals representing the tones recorded on the tracks 18.
  • the speaker apparatus or means 12 is shown as including an amplifier 24 and loudspeaker 26, although it may include devices such as tremolo and swell controls and the like.
  • the switching apparatus 14 includes a piano-type keyboard with keys 28 that are depressed by a musician to select the tones to be played.
  • Each key 28 of the switching apparatus 14 is pivotally mounted on a pivot bar 30, so that when a musician depresses a forward part 32 of the key, a rearward part 34 moves upwardly.
  • a row of switch members 36 extend along the rearward end of the keys so that depression of a key deflects a corresponding switch member.
  • the switch members 36 are constructed of a resilient electrically conductive material such as berrylium copper, and they are held in place between a pair of bars 38, 40 that are mounted on the housing 42 of the organ.
  • a bus bar 44 is also provided which electrically connects all of the switch members 36 together, and the bus bar is connected to the speaker arrangement 12.
  • a contact assembly 46 is located above the switch members 36.
  • the contact assembly 46 includes a circuit board 48 which has a row of conductive pads 50 extending parallel to the row of switch members 36.
  • Each pad 50 is connected to a different tone generator 22, so that when a switch member 36 is coupled to a pad 50, a signal from one of the tone generators passes through the switching arrangement into the speaker arrangement 12. It would be possible to have each switch member 36 directly contact a corresponding pad 50 to complete the circuit from a tone generator to the speaker. However, this could produce a clicking sound when a switch member 36 contacts a metallic pad 50, particularly where a musician operated the key rapidly, and could also produce undesirable electrical transients.
  • the contact assembly 46 includes a pair of insulative spacer strips 52, 54 which extend along either side of the row of pads 50 on the circuit board, and an intermediate conductive strip 56 which extends between the two spacer strips 52, 54.
  • the intermediate strip 56 is constructed of a flexible material of moderate resistance, and preferably of an elastic material such as a soft conductive rubber or plastic.
  • PVC polyvinylchloride
  • Such a material largely resembles rubberized electricians tape, that is, it is easily deflected and deformed, or stretched, as compared to steel or copper material of the same thickness, but returns to its original shape if not excessively deflected.
  • Another embodiment of the invention employs a soft rubber impregnated with particles of a conductive material such as carbon.
  • the spacers 52, 54 hold the intermediate strip 56 so that it extends at a position spaced a small distance below the row of pads 50 on the circuit board.
  • a key 28 deflects a switch member 36 upwardly, the end 36E of the switch member presses upwardly against the intermediate strip 56 at a location between the spacers 52, 54.
  • the switch member end 36E deflects a region of the intermediate strip 56 against the pad 50 that lies immediately above it. Only the region of the intermediate strip 56 that is contacted by the switch member 36 is substantially deflected (it and surrounding portions are stretched), so only that region of the intermediate strip contacts a pad.
  • the switch member 36 springs downwardly to its original position, the deflected and stretched portion of the intermediate strip 56 contracts back to its original position wherein it is spaced from the pad 50 that lies immediately above it.
  • the intermediate strip 56 greatly reduces mechanical noise because very little noise is produced when a switch member hits the relatively soft intermediate strip, or when a region of the strip hits a conductive pad 50. Even if a small square piece of the PVC material were attached directly to the pad 50, mechanical noise would be reduced when a switch member 36 hits it. However, the fact that the intermediate strip is spaced from the pad and must be stretched and deflected by the switch member means that there is a more gradual application of pressure by the switch member 36, and mechanical noise is reduced to an even smaller level. In the same manner, the intermediate strip damps vibrations of the switch member 36 before contact is made with a pad 50, so that no breaks in the contact are made once contact is established, and therefore this source of noise is eliminated.
  • the relatively soft material of the intermediate strip 56 undergoes a decrease in resistance during the first portion of compression. Accordingly, signal transients are reduced somewhat. For example, if a tone generator signal has an appreciable value at the instant when the intermediate strip touches a conductive pad 50, the signal strength reaching the speaker apparatus 12 will be somewhat attenuated until the fraction of a second later when the intermediate strip region is pressed hard against the pad and a larger area of the intermediate strip is contacting the pad. Thus, there is a minimization of the sudden rise in applied voltage as contact is established.
  • each photocell generator 22 had an internal and output impedance of about 50k ohms and the amplifier of the speaker apparatus had an input impedance of about 5k ohms.
  • the initial resistance, or impedance of the intermediate strip region should be at least 50k ohms to greatly reduce the initial signal.
  • the final impedance of the intermediate strip region should be low compared to the impedance of the tone generator or speaker arrangement, e.g., less than 5k ohms, so that a maximum portion of the signal reaches the speaker arrangement.
  • Carbon-impregnated PVC strips have been constructed and used, whose impedance decreases from over 50k ohms to less than lk ohms.
  • tone generators such as those which employ photocells that sense a light beam of variable intensity, generate an appreciable DC signal.
  • the DC bias can produce large transients that create popping sounds when a key is first depressed.
  • the intermediate strip 56 is connected through a capacitor 58 and high resistance 60 to ground, as shown in FIG. 3. This is the same ground potential to which each photocell 22 is connected (each photocell 22 has one side grounded and the other side connected to a pad 50).
  • a series capacitor 62 is connected in series with the speaker assembly 12.
  • Each of the tone tracks of the record disc have approximately the same average width, so that each of the photocells 22 carries approximately the same DC bias.
  • the capacitor 58 charges up to the DC bias of the photocells 22.
  • the capacitor 62 leading to the speaker assembly charges up to the DC bias of the photocells.
  • FIG. 4 illustrates the arrangement of the pads 50 on the circuit board 48.
  • the circuit board includes a backing board 64 of insulative material, and includes numerous conductive strips 66. Each conductive strip 66 is integral with one of the pads 50 and extends to one end 68 of the circuit board. The fact that all of the conductive strips 66 terminate at one end 68 of the board enables connection of the strips, and therefore of the pads 50, through the use of a plug-type connector 70.
  • the circuit board 48 can be constructed in a conventional manner, as by adhesively attaching a sheet of copper to the backing board 64, and etching away regions of the copper as determined by a mask.
  • the two spacer strips 52, 54 can be applied with an adhesive, and the intermediate strip 56 can be applied over the spacer strips, also by use of an adhesive.
  • one of the spacer strips 54 is thicker than the other 52, so that the intermediate strip 56 extends at an incline with respect to the pads 50. It has been found that this arrangement, with the switch member 36 depressing a region of the intermediate strip closer to the thicker spacer, allows for a more rapid return of the intermediate strip when the switch member springs to its original position. This is particularly important if the musician has held down the key for more than a few seconds, because the PVC material will temporarily retain the shape to which it has been stretched, and it is then important that the strip return as quickly as possible to its original shape.
  • the invention provides an organ switching arrangement which minimizes noises that might otherwise be produced at the instant when switches are closed, and which enables the mass production of apparatus with many switches at low cost.
  • Noise is minimized by the use of an intermediate conductive member between two switch contacts, which is originally spaced from both contacts but which touches the contacts in succession as the switch is closed.
  • the intermediate member is preferably constructed of a soft flexible material, such as soft conductive plastic, a conductive rubber, or other elastomeric material. Manufacturing costs are minimized by utilizing a strip-shaped intermediate member that extends between two rows of contacts (the switch members 36 and pads 50), and by constructing one row of contacts as a circuit board. This construction minimizes the number of individual parts that must be interconnected.
  • supporting means for supporting said intermediate member between said elements and spaced from each of them, so that when said second element is deflected by a key towards the said first element it engages and deforms a contact region of said intermediate member against said first element, said supporting means holding said intermediate member so it does not move with said second element until said second element is deflected and engages said contact region of said intermediate member;
  • said intermediate member includes a strip of stretchable material extending between said rows of elements;
  • said supporting means supports side portions of said strip so that said strip is taut.
  • An organ keyboard arrangement comprising:
  • spacer means holding said strip of elastic material so it extends parallel to but spaced from said row of contact regions and in a taut condition
  • a plurality of moveable members positioned for individual manually controlled movement to press and stretchably deflect different preselected regions of said strip of elastic material against corresponding contact regions.
  • said moveable members are positioned to lie spaced from said strip of material prior to manually controllable movement, so that said members must move a distance before they engage said strip.
  • An organ keyboard comprising:
  • a row of manually operable keys pivotally mounted on said housing for deflecting said resilient contact members against regions of said intennediate strip lying between said spacers, to deflect said regions against said contacts on said board.
  • one of said spacer strips is thicker than the other.
  • spacer means holding said strip of elastic material so it extends parallel to but spaced from said row of contact regions;
  • contact members defining a second set of contact regions, said contact members positioned for individual movement by different manually operable keys, so their contact regions press and deflect different preselected regions of said strip of elastic material against corresponding contact regions of said first set;

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  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Acoustics & Sound (AREA)
  • Multimedia (AREA)
  • Push-Button Switches (AREA)
  • Electrophonic Musical Instruments (AREA)
US108841A 1971-01-22 1971-01-22 Organ keyboard switching system Expired - Lifetime US3657460A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US10884171A 1971-01-22 1971-01-22

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US3657460A true US3657460A (en) 1972-04-18

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Application Number Title Priority Date Filing Date
US108841A Expired - Lifetime US3657460A (en) 1971-01-22 1971-01-22 Organ keyboard switching system

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US (1) US3657460A (enExample)
CA (1) CA950717A (enExample)
DE (2) DE7201295U (enExample)
FR (1) FR2122955A5 (enExample)
GB (1) GB1317078A (enExample)
IT (1) IT948876B (enExample)

Cited By (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3746820A (en) * 1972-02-22 1973-07-17 D Holder Pressure board for the electrical contacts for an electric organ
US3769869A (en) * 1972-04-24 1973-11-06 Opsonar Organ Corp Electronic musical instrument keying assembly providing a minimum of electrical noise
US3777090A (en) * 1972-07-26 1973-12-04 Datanetics Corp Linear cam actuated diaphragm switch with lost motion actuator
JPS4971772U (enExample) * 1972-10-05 1974-06-21
US4052923A (en) * 1976-06-22 1977-10-11 Cohn J M Electrical control devices
US4079651A (en) * 1976-01-30 1978-03-21 Nippon Gakki Seizo Kabushiki Kaisha Touch response sensor for an electronic musical instrument
US4272657A (en) * 1978-01-26 1981-06-09 Nippon Gakki Seizo Kabushiki Kaisha Keyboard assembly for electronic musical instruments
US4351995A (en) * 1979-09-08 1982-09-28 Alps Electric Company, Ltd. Vibration-preventing mechanism for use in a push button switch
EP0065587A1 (en) * 1981-05-26 1982-12-01 James Myron Cohn Electrical control device using a potentiometer
US4365536A (en) * 1980-10-27 1982-12-28 Whirlpool Corporation Sliding actuator membrane switch for organ keyboard
US4418605A (en) * 1980-06-25 1983-12-06 Pratt-Read Corporation Keyboard for musical instrument
US4500756A (en) * 1982-03-19 1985-02-19 Pratt-Read Corporation Keyboard switch having a deformable membrane formed of cellular urethane
US20060032367A1 (en) * 2004-08-11 2006-02-16 Chun-Kuan Lin Keyboard device for an electronic musical instrument

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3140771C2 (de) * 1981-10-14 1983-11-24 Rudolf Schadow Gmbh, 1000 Berlin Mehrfach-Flachschalter

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2575230A (en) * 1948-07-03 1951-11-13 Baldwin Co Electrically noiseless progressive contact means
US2848920A (en) * 1955-03-02 1958-08-26 John M Lester Key contact system for electronic organs
US2959693A (en) * 1955-12-30 1960-11-08 Baldwin Piano Co Key switching system for electrical musical instruments
US3041568A (en) * 1959-08-07 1962-06-26 Baldwin Piano Co Renewable switch construction
US3060784A (en) * 1959-07-17 1962-10-30 Wurlitzer Co Switch arrangement for electronic organs
US3474182A (en) * 1965-04-14 1969-10-21 Armel Arts Mecanique Electroni Musical instrument employing single unijunction transistor oscillator in which volume is controlled by key displacement
US3524375A (en) * 1968-04-01 1970-08-18 Alvin S Hopping Simulated stringed electronic musical instrument having gradual switch for attack,decay and volume control
US3564105A (en) * 1968-07-01 1971-02-16 Nippon Musical Instruments Mfg Electronic musical instrument key assembly with pressure sensitive resistor

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2575230A (en) * 1948-07-03 1951-11-13 Baldwin Co Electrically noiseless progressive contact means
US2848920A (en) * 1955-03-02 1958-08-26 John M Lester Key contact system for electronic organs
US2959693A (en) * 1955-12-30 1960-11-08 Baldwin Piano Co Key switching system for electrical musical instruments
US3060784A (en) * 1959-07-17 1962-10-30 Wurlitzer Co Switch arrangement for electronic organs
US3041568A (en) * 1959-08-07 1962-06-26 Baldwin Piano Co Renewable switch construction
US3474182A (en) * 1965-04-14 1969-10-21 Armel Arts Mecanique Electroni Musical instrument employing single unijunction transistor oscillator in which volume is controlled by key displacement
US3524375A (en) * 1968-04-01 1970-08-18 Alvin S Hopping Simulated stringed electronic musical instrument having gradual switch for attack,decay and volume control
US3564105A (en) * 1968-07-01 1971-02-16 Nippon Musical Instruments Mfg Electronic musical instrument key assembly with pressure sensitive resistor

Cited By (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3746820A (en) * 1972-02-22 1973-07-17 D Holder Pressure board for the electrical contacts for an electric organ
US3769869A (en) * 1972-04-24 1973-11-06 Opsonar Organ Corp Electronic musical instrument keying assembly providing a minimum of electrical noise
US3777090A (en) * 1972-07-26 1973-12-04 Datanetics Corp Linear cam actuated diaphragm switch with lost motion actuator
JPS4971772U (enExample) * 1972-10-05 1974-06-21
US4079651A (en) * 1976-01-30 1978-03-21 Nippon Gakki Seizo Kabushiki Kaisha Touch response sensor for an electronic musical instrument
US4052923A (en) * 1976-06-22 1977-10-11 Cohn J M Electrical control devices
US4272657A (en) * 1978-01-26 1981-06-09 Nippon Gakki Seizo Kabushiki Kaisha Keyboard assembly for electronic musical instruments
US4351995A (en) * 1979-09-08 1982-09-28 Alps Electric Company, Ltd. Vibration-preventing mechanism for use in a push button switch
US4418605A (en) * 1980-06-25 1983-12-06 Pratt-Read Corporation Keyboard for musical instrument
US4365536A (en) * 1980-10-27 1982-12-28 Whirlpool Corporation Sliding actuator membrane switch for organ keyboard
EP0065587A1 (en) * 1981-05-26 1982-12-01 James Myron Cohn Electrical control device using a potentiometer
US4500756A (en) * 1982-03-19 1985-02-19 Pratt-Read Corporation Keyboard switch having a deformable membrane formed of cellular urethane
US20060032367A1 (en) * 2004-08-11 2006-02-16 Chun-Kuan Lin Keyboard device for an electronic musical instrument

Also Published As

Publication number Publication date
DE7201295U (de) 1972-06-22
FR2122955A5 (enExample) 1972-09-01
IT948876B (it) 1973-06-11
CA950717A (en) 1974-07-09
GB1317078A (en) 1973-05-16
DE2201699A1 (de) 1972-08-03

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