US3068735A - Electrical musical instrument coupling system - Google Patents

Description

Dec. 18, 1962 w, ANDERSON 3,068,735

' ELECTRICAL MUSICAL INSTRUMENT COUPLING SYSTEM Original Filed March 1'7, 1958 I 2 Sheets-Sheet 1 UPPER MANUAL TIMBRE 5Y5.

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ELECTRICAL MUSICAL INSTRUMENT COUPLING SYSTEM Original Filed March 1'7, 1958 2 Sheets-Sheet 2 FIG. 2

INVENTOR. WalTeR J Amdeksq'n BY QM 2m United States Patent Ofihce 3,0li8,735 Patented Dec. 18, 1962 3,068,735 ELECTRICAL MUSICAL INSTRUMENT COUPLKNG SYSTEM Walter .I. Anderson, Elgin, 111., assignor to The Lowrey Organ @ornpany, Cool: County, 111., a corporation of Illinois Continuation of appiication Ser. No. 721,8tl1, Mar. 17,

1958. This application Oct. 25, 19619, Ser. No. 64,814

Claims. (Cl. 84-117) This invention is a continuation of my co-pending application Serial No. 721,801, filed March 17, 1958.

This invention relates to a mechanism for coupling one manual of an electronic organ to another.

The primary object of the invention is the provision of simple and dependable means for avoiding electrical interaction between the various voltage carriers of an electronic organ for improved tonal clarity and definition upon translating tone signals into audible sounds for musical expression.

In organs employing tone generators adapted to be activated by voltage applied thereto for transmission of tone signals to an output system, it has been costly with prior instruments satisfactorily to prevent electrical interaction between interrelated and interconnected circuit elements and voltage carriers. Such electrical interaction is proportional to the voltage applied at any instant to the playing key switches. In the instant case, we are concerned with the relationship to each other of the switch assemblies and associated circuit elements, each assembly consisting of a longitudinal row of switches which are operable by a similar order and relationship to each other of the playing keys of the respective manuals. It follows that when playing complicated chords on one or both manuals voltage applied at the same instant to a large number of switches can cause interference with nearby switches with attending introduction of disturbing extraneous frequencies and tonal impairment of sound at the reproducers in the output system of the instrument. My invention is therefore a means for satisfactorily overcoming the herein stated difficulties by simple and inexpensive procedures.

A furthcr object is the provision of means whereby sounds at the translator can either be made to decay rapidly or be sustained for a definite period of time, which said means enables producing versatile sound effects at any instant when playing either one of the manuals.

Other objects will be pointed to in the following description of my invention, reference being had to the accompanying drawings in which:

FIGURE 1A is a schematic illustration showing one operated condition of the coacting elements of the invention.

FIGURE 1B is a schematic illustration showing another operated condition of the coacting elements of the invention.

FIGURE 1C is a schematic illustration showing a still further operated condition of the coacting elements of the invention. v

FIGURE 2 is a schematic illustration of a further embodiment of the invention, and

FIGURE 3 is a schematic illustration of a still further embodiment of the invention.

While the accompanying drawings show only a single tone signal generator, an upper manual switch and a lower manual switch, each switch being coactive with a contact on a respective bus bar, it is understood that for each note in the instruments gamut there will be a generator formed and adapted, when activated by B+ potential, to deliver a signal of the frequency of one of the notes of the chromatic scale. In practice, all upper manual switches are coactive with respective contacts upon a common bus bar, and this is also true with respect to the lower manual switches. In each case, the bus bar will be connected to a source supplying activating potential thereto.

Similar elements throughout the several illustrated forms of my invention will be designated by like reference characters and numerals.

Referring to FIGURE 1A, G2 is a tone signal generator comprising a vacuum tube operating at any desired musical frequency, said tube having an anode A, cathode B and control grid C.

K1 is an upper manual key and K2 a lower manual key, the former connected by sticker 10 to one end of a contactor 11 and the latter connected by a sticker 10' to a contactor 14. As shown, said keys are normally biased to raised position by springs Y.

A conductor section 12 has one of its terminals connected to anode A and its opposite terminal to contactor 11 through a load resistor R1. Conductor section 16 con nects at one of its terminals to contactor 14, the opposite terminal thereof connected to contact 15 situated beneath contactor 11 and engaged therewith only when key K1 is raised, as shown, at which time, sections 12 and 16, contactors 14 and 11 and contact 15 complete one continuous conductive path to anode A.

S1 is a common conductor, one terminal of which connects to header H1 of a system T of upper manual stops S which connect to respective wave filters F. These filters connect to common output header H2, the latter connected by wire S2 to amplifier S3 of any conventional electroacoustic translator, the amplifier having a loud speaker S4. The opposite terminal of conductor S1 connects to conductor section 12 via resistor R3 and condenser C1, the point of said connection being between the anode A of generator G2 and load resistor R1.

23 is a bus bar which will have as many contacts as the one shown at 24 as there are playing keys like key K1, and, as shown, contact 24 is disposed in spaced apart relation to contactor 11 when key K1 is raised. Bus bar 23 connects to a source of B+ potential 25 of volts.

Located above contactor 14 is a bus bar 17 which will also have as many contacts like contact 18 as there are lower manual keys such as key K2. Contact 18 is connected to a similar contact 19, the latter forming an element of a coupler switch comprising a pivoted blade 21 which connects to a source of B-lpotential 22 of 180 volts.

At FIGURE 1C both keys K1 and K2 are shown depressed. Contactor 11 is engaged with contact 24 and disengaged from contact 15. Contactor 14 is engaged with contact 18 and blade 21 is disengaged from contact 19.

At FEGURE 113, key K1 is raised and contact 15 is engaged with contactor 11 and disengaged from contact 24'. Key K2 is depressed thereby engaging contactor 14 with contact 18. Blade 21 is closed against contact 19. It follows upon referring to FIGURE 1A that keys K1 and K2 being raised and blade 21 of the coupler switch moved off of contact is, the respective bus bars 17 and 23 are completely electrically isolated from each other, thereby preventing electrical interaction between them and other closely related voltage carriers. In this condition of the described elements, depression of key K1 causes engagement of contactor 11 with contact 24 with resulting transmission of activating potential to anode A of generator G2 from source 25 of B+ potential of 180 volts for activation of the generator and withdrawal of the produced signal and delivery of the signal to the upper manual system of stops. When, as shown at FIGURE 16 both keys K1 and K2 are depressed at the same time, switch blade 21 being in an open circuited condition, contactor 11 will be disengaged from contact and contactor 14 engaged with contact 18. 8+ potential from source will be delivered to anode A, thereby completely isolating the switches from each other, it having been discovered that by this simple means there is complete avoidance of electrical interaction between all voltage carriers regardless of the number of switches that are close circuited at any instant, thereby making for clarity of tones not possible of attainment with systems of the prior art.

When, as shown at FIGURE 1B, the lower manual being coupled to the upper manual, it is noted that when depressing key K2, contactor 14 engages contact 18 which is now close circuited with a source of B-lpotential of 180 volts 22, key K1 being in its raised position, potential will be applied to anode A via contact 18, contactor 14, conductor section 16, contact 15, contactor 11 and conductor section 12. As contactor 11 is off of contact 24, bus bars 23 and 17 are completely electrically isolated from each other.

In the embodiment shown at FIGURE 2, conductor 12 consists of sections 12a and 12b, load resistor R1 in section 12a and load resistor R2 in section 12b, the lower terminal of section 1217 being connected to contactor 14 of the lower manual key K2, and, as shown, contactor 11 of key K1 connects to junction point P between said resistors. The upper terminal of section 1211 of. conductor 12 connects to anode A of generator G2. Source supplies 13-}- potential of 120 volts to bus bar 23, contact 24 and contact 54. Coupler blade 51 connects by lead wire 52 to bus bar 17 and is adapted, at the will of the player to be moved either onto contact 54 or onto contact 53, the latter being an element of bus bar 5t) which connects to a source 510 of positive potential supplying volts. In other respects, the various elements comprising this embodiment of my invention are similar to corresponding elements disclosed at FIGURES 1A, 1B and 1C, except that a normally deionized glow tube NE2 is connected in section 12b of conductor 12 at a point between load resistor R2 and contactor 14 of key K2 and is adapted to be connected either in circuit with source 510 or source 50 according as blade 51 is moved onto one or the other of said contacts 53 and 54. In this embodiment of my inven tion, electrical isolation between bus bars 17 and 24 is established by the high impedance and non-conductive characteristics of said glow tube when the tube is deionized thereby completely blocking said conductor against flow of activating potential between said bus bars. With the blade engaging contact 54, 120 volts of B+ potential will be applied to bus bar 17. When key K2 is depressed, contactor 14 is energized and glow tube NE2 ionized, thereby unblocking conductor 12 and applying activating potential to anode A for withdrawing the signal and transmitting same to the output system of the instrument.

In this manner, the effective voltage on bus bars 23 and 17 is insuificient to ionize glow tube NE2, thereby preventing interaction between the switches and said bus bars.

In the embodiment shown at FIGURE 3 conductor 12 comprises sections 120 and 120., the former having load resistors R1 and R4 and charging condenser C4 and the latter a load resistor R5 and glow tube NE2. At junction point P2 between resistors R1 and R4, contactor 11a. of the upper manual key K1 is connected. The upper terminal of section 12c connects to anode A of generator G2, the opposite terminal of said section connecting to ground through condenser C4. Section 12d of conductor 12 has a contact 15a which is electrically coactive with contactor 11a, the opposite terminal of conductor section 12d being connected to contactor 66a of the lower manual key K2. Said section 120 has a glow tube NE2 connected therein between contactor 66a and load resistor R5. Contactor 66a is disposed in the space between contacts 61a and 63a, the latter connected to blade 67 and the former to contact 54a. Contact 54a is coactive with coupler blade 51a which connects to a source Siic supplying B+ potential of volts. Bus bar 230 embodying contact 24a connects to a source of 8+ voltage 25a of 180 volts. Blade 67 is disposed in the space between contacts 69a and 70a, the former adapted to be connected to source 71a supplying 13+ potential of 60 volts to contactor 67" when the latter is engaged with contact 6%. Contact 70a is adapted to supply a minus 60 volts of potential to blade 67" from source 71a when blade 67 is engaged with contact 7t)a.

When blade 51a is on contact 54a and key K2 is depressed, contactor 66:: engages contact 61a, thereby delivering 180 volts of B+ potential to glow tube NE2 ionizing same and causing application of activating potential to anode A of generator G2 via resistor R1 and charging condenser C4 through resistor R4. Assuming that key K2 has beenreturned to its raised condition, and that blade 67" is engaged with contact 69a, 60 volts of B+ potential is applied to glow tube N52 via contact 53a and contactor 66a thereby retarding discharge of condenser C4 for sustaining the tone. When blade 67" is on contact 70a, negative potential of 60 volts is applied to said glow tube thereby causing rapid discharge of condenser C4; and corresponding rapid decay of the tone. This feature of herein disclosed invention forms the subject of a divisional application of my earlier filed application Serial No. 721,801, filed March 17, l958, said divisional application bearing Ser. No. 64,8l8, filed Oct. 25, 1969.

What I claim as my invention is:

1. Stop mechanism for an electronic organ having upper and lower manuals, a vacuum tube generator producing a. signal of given musical frequency and provided with a signal output electrode, an upper manual tone color system providing output signals of the waveforms of different stops, an amplifier and associated loud speaker, stop switches operatively connecting the tone color system to said amplifier, depressible upper and lower manual keys each having a switch actuable thereby, circuitry connecting said electrode to the tone color system and the lower manual key switch to the upper manual key switch only when the upper manual key is raised, and means for supplying activating potential to said electrode when depressing the upper manual key and for similarly supplying activating potential to said electrode when the lower manual key is depressed and the upper manual switch is raised.

2. Stop mechanism as set forth in claim 1 in which a high impedance electronic device connects the lower -manual switch to the upper manual switch and the lower manual switch to the potential supply means for lowering the impedance of said device and deiivering activating potential to said electrode when the lower manual key is depressed.

3. Stop mechanism as set forth in claim 2 in which said high impedance device comprises a glow tube wl ch is deionized when the lower manual switch is raised.

4. Mechanism for coupling the lower manual to the upper manual of an electronic organ comprising, a vacuum tube generator producing a signal of given musical frequency, said generator having a signal output electrode, an upper manual timbre control system, an amplifier and associated loud speaker coupled to the timbre control system, depressible upper and lower manual keys each having a contactor actuable by the key and a contact coactive with said contactor, each key being resiliently biased to a raised position disengaging the contactor thereof from its coactive contact, circuitry connecting the electrode to said amplifier and the contactor of the upper manual key to said electrode and connecting the contactor of the lower manual key to said electrode only when the upper manual key is raised and the lower manual key is depressed, and means for supplying positive potential to said contacts for energization of said contactors and conduction of said potential to said electrode.

5. Mechanism as set forth in claim 4 wherein the circuitry comprises electrically coactive first and second sections, the first section directly connecting the contactor of the upper manual key to said electrode, the second section electrically connecting the contactor of the lower manual key to the electrode via said first section only when the uper manual key is raised.

6. Mechanism as set forth in claim 5 wherein the second section of said circuitry has a contact engaged by the contactor of the first section of said circuitry when the upper manual key is raised.

7. Mechanism as set forth in claim 6 wherein the second section of said circuitry contains a normally deionized glow tube for blocking said section against flow of potential therethrough when the contactor of the upper manual key is engaged with its coactive contact and for unblocking said second section of said circuitry to ionize said tube to efiect conduction of positive potential to said electrode when the upper manual key is raised and the lower manual key is depressed.

8. Mechanism as set forth in claim 5 in which the first section of the circuitry has a load resistor between the contactor of said section and said electrode.

9. Mechanism as set forth inclaim 7 in which the first and second sections of said circuitry each has a load resistor therein and the load resistor in the second section is connected between the contactor of the upper manual key and said glow tube.

10. In an electronic musical instrument, a vacuum tube producing a tone signal of given musical frequency and provided with a signal output electrode, upper and lower manual keys each having a switch comprising a contactor operated by the key and a contact coactively associated with said contactor, each key being resiliently biased to a raised position to disengage the contactor thereof from its associated contact, circuitry in which said contactors are operatively contained, and means for energizing said contacts with positive potential, said circuitry connecting said contactors to said electrode and in operating relation to their respective contacts to electrically disable the switch of the lower manual key when the upper manual key is depressed.

References Cited in the file of this patent UNITED STATES PATENTS 2,103,439 Swart Dec. 28, 1937 2,169,842 Kannenberg Aug. 15, 1939 2,513,109 Roth June 27, 1950 2,811,069 Faulkner Oct. 29, 1957 2,823,310 Anderson Feb. 11, 1958 OTHER REFERENCES Keister et al.: The Design of Switching Circuits, pages 48-49; New York, Van Nostrand Co., 1951.

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