04/859217

10/19/1971

08/15/1969

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84/655

984/330, 84/682, 84/686, 84/721, 84/670

G10H1/18; G10H1/00

84/1.01,1.13,1.19,1.08,1.17D,1.17E,1.17O,1.03,1.14

3518352

RHYTHM GENERATING CIRCUIT FOR MUSICAL INSTRUMENT

June 1970

Plunkett

Saalbach, Herman Karl

Chatmon Jr., Saxfield

CROSS-REFERENCE TO RELATED APPLICATION

The present application is a continuation-in-part of U.S. application Ser. No. 753,978 filed Aug. 20, 1968.

What is claimed is

1. In an organ comprising a plurality of keyboard manuals, coupler switches, sound producing control means and keyers, the improvement comprising;

2. In an arrangement as set forth in claim 1 further including bus bar means associated with each of said keyboard manuals, coupler switches and sound producing control means, each of said bus bar means including switch means for selectively connecting each of said bus bar means to a source of potential.

3. In an arrangement as set forth in claim 2 wherein said control means is comprised of pulse generating means adapted to produce a plurality of control pulses cyclically, each of said control pulses in a cycle being operatively connected to a predetermined combination of switching means to operate said switching means and energize a predetermined combination of bus bar means.

4. In an arrangement as set forth in claim 3 wherein, each of said sound producing control means includes holding means adapted to maintain the respective sound producing control means which are connected to a selected energized bus bar means in the energized state under the control of a plurality of discrete pulses.

5. In an arrangement as set forth in claim 3 wherein said holding means is a circuit which is capable of being locked by one pulse an unlocked by another pulse.

6. In an arrangement as set forth in claim 5 wherein said circuit is an electronic bistable circuit.

7. In an arrangement as set forth in claim 6 wherein said electronic bistable circuit includes two complementary transistors connected to lock each other on when a first pulse is applied to the base of one of said transistors.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention is broadly related to the field of organs and more particularly to an electronic switching assembly useful as a key action for organs.

2. Description of the Prior Art

In electric organs, and also in pipe organs, each of the keys on the various keyboards, pedals, stop knobs and other instrumentalities, are utilized to control a plurality of intermediate electrical switches which in turn control the ultimate sound producing mechanisms. These key or pedal and stop operated switches are often formed in a matrix arrangement so that one key and one stop may provide a plurality of different combinations of switching and are commonly called key actions or couplers. Key actions can be coupled directly to manual keyboards or pedal keyboards and in addition this key action can also be remotely controlled by mechanical actuators commonly known and used in the art.

In the key action switches for use in organs, it is common and conventional practice to utilize relatively light contact pressure for closing the contacts of the actuated switch or switches. After several days of inactivity, quite often an insulating oxide film will form on the switch contact which will not be broken when the organ is again used and the key is pressed to actuate the switches. Hence, the insulating film will prevent the switch contacts from mating and no sounds will be produced by the organ unless this insulating oxide film is broken and conductive contacts can be made.

Key actions or couplers are sometimes rendered inoperative by the collection of dirt and dust which will accumulate on the action, particularly if the switches are exposed. Also, in prior art organs, the key actions needed adjustments periodically due to the manufacturing process.

A major drawback of the prior art organs resided in the fact that a separate key action was needed for each keyboard or pedal board arrangement thereby greatly increasing the manufacturing cost due to the increased number of parts and the increased assembly time required for assembling a key action. Furthermore, a great deal of space was required in the prior art organs to accommodate the large number of key actions.

In recent years, some of these disadvantages, such as exposed contacts and frequent adjustments, have been overcome by the use of solid-state keyers. However, even with the use of solid-state keying, many disadvantages still existed since on an average sized organ at least five keyers were necessary to accommodate the full complement of couplers. This resulted in the use of many components which are subjected to failure, are costly and require extreme care in assembling due to the multiplication of connections, solder joints, all of which can contribute to failure of operations. SUMMARY OF THE INVENTION

According to the present invention, all of the above-mentioned drawbacks existing in the prior art key actions for electric organs are completely removed and a simple, compact, efficient and reliable key action is provided. In the present invention, a single solid-state keyer, which may be referred to as a diode keying arrangement, is utilized in place of the plurality of key actions which were required in prior art organs having a plurality of keyboards, pedal boards and stops.

According to the present invention, a pulse generator is provided which generates a plurality of pulses in continuous sequence to sequentially connect each keyboard or coupler to the sound producing relays for operations thereof. Thus, when the pulse generating device is operating, even though the organist is not playing the organ, the opportunity for completing a circuit from the organ console to the sound producing relays is always present.

According to the present invention, it is possible to use the single diode keyer for any number of couplers merely by generating a number of pulses in sequence equal to the number of couplers so that each coupler may be connected periodically in sequence.

Thus, it is obvious that the present invention substantially reduces the space requirements in an electrically operated organ, increases the reliability of performance due to the reduced number of electrical connections and the use of solid state switching in lieu of exposed electrical contacts, and substantially reduces cost due to the greatly reduced number of parts required in a particular organ.

Other features of the invention will be pointed out in the following description and claims and illustrated in the accompanying drawings, which disclose, by way of example, the principles of the invention and the best mode which has been contemplated of applying those principles.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a wiring diagram showing the electrical connections between the pulse generator and the diode keyer;

FIG. 2 is a wiring diagram showing the connection of the diode keyer with respect to a single key operated switch, as single coupler switch and a single sound producing relay;

FIG. 3 is a graphical representation of the output of the pulse generator;

FIG. 4 is a schematic showing of a modified arrangement for holding a circuit closed;

FIG. 5 is a simplified schematic diagram of a circuit which illustrated the principles of operation of an output circuit according to another embodiment of the invention; and

FIG. 6 is a detailed schematic diagram of the output circuit according to another embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION

The conventional electrically operated organ may be provided with a plurality of keyboards, a pedal board and a plurality of stops for controlling a plurality of switches which in turn will operate the desired combination of relays for the production of sound. For the sake of simplicity, the description of the operation of the present invention will be restricted to the use of a single key in conjunction with three couplers and two sound producing relays. However, it is to be understood that the same principles of operation would apply to a plurality of key operated switches, pedal operated switches, stop operated switches and sound producing relays.

Turning first to FIG. 2 which illustrates the operation of a diode keyer, a single key operated switch K1 and a single coupler switch C16 are connected in circuit with the diode keyer to operate a sound producing control relay 5. Upon closing of the key switch K1, a positive potential appears at point 1. If coupler switch C16 is closed, this positive potential is now at ground potential thereby not allowing anything to happen. However, if the coupler switch C16 is open, this positive potential appears at the base of transistor 4 thereby causing transistor 4 to assume an "ON" condition allowing relay coil 5 to operate. Resistor 3 is to limit the current flow to the transistor 4 and diodes 6 and 7 are to prevent "feedback" from other portions of the circuit. Diode 8 is used to suppress the electrical "kickback" of coil 5. The circuit of FIG. 2 thus far described, absent the capacitor 9, is conventional and well known by those skilled in the art. In prior art organs utilizing the diode key arrangement just described, this circuitry is repeated for each and every key and coupler arrangement in the entire organ. In order to use the diode keying circuit just described on a time sharing basis with a plurality of manuals by means of a pulse generator which sequentially connects each manual to the diode keying arrangement, the capacitor 9 has been added to the circuit. This capacitor allows the relay coil 5 to maintain an "ON" condition by a series of pulses instead of a steady DC power source. It is also possible to have the capacitor in the base circuit of the transistor 4 but this arrangement would require additional components which are well known by those skilled in the art.

Another possible mode for maintaining the relay 5 energized in lieu of the capacitor arrangement previously described is shown in FIG. 4. A utility circuit includes a reed switch 60 which is normally in the "open" condition. A magnetic core 64 is slidably mounted in a hollow cylindrical nonmagnetic sleeve 62 around which the coil 70 is wrapped. The core 64 is normally maintained in the position shown in FIG. 4 remote from the reed switch 60 by the coil spring 68 extending between the sleeve 62 and the flange 66 on the core 64. If a train of discrete pulses is applied to coil 70 each pulse will create a magnetic field to draw the core 64 into the sleeve into close proximity to the reed switch 60 causing the switch to close. Upon the termination of each pulse the diode 72 which is connected across the coil 70 retards the collapse of the magnetic filed. This retardation plus the inertia of the magnet 64 results in the reed switch 60 remaining closed until a subsequent pulse is applied to the coil 70.

The pulse generator, generally indicated at 30 in FIG. 1, may be any one of many different generators. As illustrated in FIG. 1 the pulse generator is comprised of a 10 kc./s oscillator 32 connected to a shift register 34 which in turn is connected to a gate amplifier 36. The gate amplifier 36 may be provided with a number of outputs equal in number to the number of pulses being generated for the particular application. Three such outputs 37-39 are shown coupled to further circuitry. Operation of the circuit in the presence of a pulse on each of these lines is discussed below. The dashed lines are used to illustrate other outputs from the gate amplifier 36. A SWELL manual bus bar 40 and a GREAT manual bus bar 42 are provided for each of two keyboard manuals. Each of these bus bars is adapted to be connected to a source of positive potential by means of switches 12 and 13, respectively. The switches 12 and 13 may be transistors. Upon closure of either switch K1 by depressing a key on the SWELL manual or GREAT manual or K1' the SWELL manual bus 40 or the GREAT manual bus 42, respectively, may be connected to the diode keyer in the dotted circle 44. The diode keyer 44 is similar to that described above with respect to FIG. 2.

A plurality of couplers bus bars such as SWELL to GREAT, SWELL to SWELL, etc. are each provided as bus bars 46, 48 and 50, respectively. Individual coupler switches C4', C8' and C16' within a particular coupler bus, are provided to selectively connect the particular coupler bus to a diode keyer 44 and the individual coupler switches in a particular coupler bus may be preset by means of a combination action or set individually as desired. The individual coupler switches allow the organist to play a specific pipe in an organ depending upon the closure of a selected key in a manual. Coupling is well known in the organ art. It is a way of squeezing more out of a given number of pipes without substantial cost. Coupler switches may be used to change the pitch of a note played on a keyboard manual. For example, let us consider intramanual coupling. Such coupling has its entire effect on one manual of the organ. When coupling switch C16' on the SWELL to SWELL bus bar 48 is set all voices on the SWELL manual produce a sound an octave lower than would be sounded if coupling switch C8' was set. A more detailed description of coupling is given in Electronic Musical Instruments, Richard H. Dorf, Radiofile, 1968. The three bus bars 46, 48 and 50 are each connectable to a negative potential by means of switches 20, 10 and 11, respectively, These three switches 20, 10 and 11 are transistors.

Although a particular electric organ may have a plurality of different organs, only the SWELL relay 52 and the GREAT relay 54 are shown in FIG. 1 for purposes of illustration. The SWELL relay 52 may be connected to the SWELL bus 53 by means of transistor 16 which may be turned "ON" or "OFF" by means of a signal received from the diode keyer 44. The SWELL bus bar 53 is connectable to a negative potential by means of a transistor 14R which is turned "ON" and "OFF" by means of a pulse received from the pulsing arrangement 30. Likewise, the GREAT relay 54 is connected to the GREAT bus bar 55 by means of the transistor 41 which is controlled by the diode keyer 44. The GREAT bus bar 55 is connectable to a source of negative potential through a transistor 15R under the control of a pulse from the pulsing arrangement 30.

FIG. 3 represents the output of the pulse generator. With the passing of time a pulse 17 is generated. Immediately on ceasing, pulse 18 is generated and following its completion pulse 19 is generated. This cycle is repeated continuously at a fixed rate depending on the motor speed or master control oscillator triggering a ring counter or shift register. The number of pulses generated is dependent upon the number of keyboards and coupler buses in the particular organ under consideration.

The average two manual organ console lists coupler (C) switches as follows:

Swell to SWELL 16'

Swell to SWELL 8'

Swell to SWELL 4'

Swell to GREAT 16'

Swell to GREAT 8'

Swell to GREAT 4'

Great to GREAT 16'

Great to GREAT 8'

Great to GREAT 4'

In the above listing, the prime markings are the pitches of the tone as compared to what is being played at the keyboard. As an example, with a 16' switch in operation, the tone produced will be an octave lower than what is being played. With an 8' switch in operation, the pitch is known as Unison pitch. With a 4' switch in operation, the tone produced is an octave higher. In addition to changing pitches within a manual, one manual may be coupled to another manual at various pitches.

For an organist to produce a tone from the keyboard, a coupler switch has to be opened by means of moving the coupler tablet to the "ON" position and a K switch has to be closed by the pressing of a key. This in itself would not produce a tone if all the bus lines shown in FIG. 1 were to remain disconnected from a power source. However, the bus lines do not remain in the open position due to the sequential closing of a series of bus switches controlled by the pulse generator. In the particular example shown, the bus switches are transistors which may be controlled by the pulses from the pulse generator. By preselected wiring of the pulses through diodes to their respective bus switch, the diode keyer is made to operate as follows.

Pulse 17 will operate the SWELL to SWELL coupler bus and for this to take place the generation of pulse 17 on line 38 will cause transistors 10, 12 and 14R to be closed. Pulse 18 on line 37 will operate the SWELL to GREAT coupler bus and for this to take place the generation of pulse 18 will cause transistors 20, 13 and 14R to be closed. Pulse 19 on line 39 will operate the GREAT to GREAT couplers and for this to take place the generation of pulse 19 will cause the transistors 11, 13 and 15R to be closed. The above sequence of pulses and operations will be repeated indefinitely as long as the pulse generator is operating.

More specifically, the operation of the device as a result of the generation of the pulse 17 is as follows. The pulse 17 will cause the transistor 12 to turn "ON" thereby energizing the SWELL manual bus bar 40. The same pulse 17 will simultaneously turn transistor 10 to the "ON" state thereby energizing the SWELL to SWELL coupler bus bar 48 and turn the transistor 14R to the "ON" state thereby energizing the SWELL bus bar 53. Thus, on closing the key switch K1 of the manual, a positive potential will appear at the junction point of the two diodes in the diode keying arrangement 44 similar to the manner described with respect to FIG. 2. If the coupler switch C16' on the SWELL to SWELL bus 48 is open and the remaining coupler switches C8' and C4' are closed as a result of individual selection or as the result of a preset combination action, the positive potential will be applied to the base of transistors 41 and 16. However, since the SWELL bus 53 is energized and the GREAT bus 55 is deenergized as the result of pulse 17, only the transistor 16 will be turned "ON" thereby energizing the SWELL relay 52.

Another way of phrasing the above operation is that a diode keyer, of which is shown within the dotted circle 44 in FIG. 1, is not allocated to any particular keyboard or coupler bus bar or coupler switch. Instead, it is community property and momentarily "borrowed" by each group of coupler switches in conjunction with each keyboard. Even though the organist is not playing the organ, the opportunity for completing a circuit from the organ console is always present.

FIG. 5 illustrates in simplified form an output circuit which may be substituted for the output circuit shown in FIG. 1. For purposes of illustration, it will be assumed that the output circuit shown in FIG. 5 is substituted for the SWELL output circuit comprising the transistors 14R and 16 and the relay 52. The relay coil 52 is connected in series with a resistor 62 to a source of negative potential. Resistor 62 has a value which prevents the relay from closing but is not so great as to prevent the relay from holding "ON" once it has closed. If a signal is received from the key line from the diode keyer 44 the relay 52 will not operate with resistor 62 in series. If, however, switch 14R is closed, the current is sufficient to operate the relay. Once the relay has operated, closing relay contact 60, the positive potential on the contact will cause the relay to hold itself "ON" as well as to operate the load 64. Relay contact 60 will remain closed even after switch 14R is opened. When switch 16 is closed, the relay 52 will unlock itself and stay unlocked until another pulse is received from the key line simultaneously with the closing of switch 14R. The pulse that closes switch 16 is the "OFF" pulse. This pulse is generated by the pulse generator 30 and occurs before each pulse 16, shown in FIG. 3.

Due to the slow operation of a relay, the relay 52 shown in FIG. 5 is not practical in actual use. In reality, the relay 52 may be a silicon-controlled rectifier, a unijunction transistor, two transistors, or any number of electronic devices capable of being locked by one pulse and unlocked by another pulse. FIG. 6 illustrates an electronic output circuit which may be used in place of the relay 52. This circuit includes a pair of complementary transistors 70 and 72 connected to form a bistable circuit. The key line from the diode keyer 44 is connected to the base of transistor 62 through series connected resistors 74 and 76. A pulse on the key line is prevented from turning transistor 72 "ON" by normally conducting transistor 78 which is connected to the junction of resistors 74 and 76 by a diode 80. However, when switch 14R is closed, transistor 82 is turned "ON" which robs base current from transistor 78. This causes transistor 78 to turn "OFF". Current now flows from the key line to the base of transistor 72, turning it "ON". This in turn causes transistor 70 to turn "ON" thereby locking both transistors "ON". Transistors 70 and 72 will remain locked "ON" even after switch 14R is opened. In order to turn transistors 70 and 72 "OFF" it is necessary to operate switch 66. Closing switch 66 turns on transistor 84. Transistor 84, when it is conducting, connects the base of transistor 72 through diode 86 to a source of negative potential. This causes transistor 72 to turn "OFF" which in turn causes transistor 70 to turn "OFF".

Obviously, many modifications and variations of the present invention are possible in the light of the above teachings. It is, therefore, to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described.