Pedal actuated musical chord system

A musical chord system includes a pedal console comprising a plurality of foot-actuated pedal switches, a chord selection switch console comprising a plurality of chord selection switches associated with said pedal switches, and diode matrix logic means interconnecting the chord selection switches with the tone generating circuitry of a conventional electronic musical instrument such as an electric organ whereby chords are sounded upon depression of the foot pedals. By adjustment of the corresponding chord selection switch, each foot pedal can be set to produce any desired one of a multiplicity of possible chords. Switches are also provided to permit the chords to be sounded on different octaves and keyboards or combinations thereof. A priority interconnect circuit prevents more than one chord from being played when two pedals are simultaneously depressed. A lower musical keyboard sustaining circuit permits the upper manual keyboard to be pulsed with alternating partial and full depression of a pedal.

BACKGROUND OF THE INVENTION 
1. FIELD OF THE INVENTION 
This invention relates to electronic musical instruments that generate 
tones corresponding to musical notes and, more particularly, to 
foot-actuated pedal consoles for selectively producing chords from 
combinations of such notes by utilizing the existing tone generating 
circuitry of such electronic instruments. 
2. DESCRIPTION OF THE PRIOR ART 
Modern musical compositions often call for the use of electronic musical 
instruments to provide background accompaniment for a lead instrument, 
such as a guitar, horn or reed instrument. The background accompaniment 
typically consists of a repetitive sequence of chords or combinations of 
musical notes played on an electronic instrument such as an electronic 
organ. 
Conventional electronic circuitry exists which permits an unskilled 
musician to provide a chord accompaniment to a melody. A system widely 
used on electronic organs permits the generation of musical chords when 
certain "root" note keys are depressed on a manual keyboard. Another 
system described in Craegar et al, U.S. Pat. No. 3,962,945, comprises a 
remote foot-actuated pedal console that interfaces with traditional 
electronic organ circuitry to selectively generate chords or note 
combinations upon depression of pedals. This latter arrangement offers the 
advantage that the lead musician himself can play the chord accompaniment 
with his feet while leaving his hands free to play the lead instrument. 
Such existing chord composing systems suffer the disadvantage that 
depression of a particular key or pedal results in the generation of a 
single preset chord, and no means exists to vary the chord or note 
combination produced by depression of that key or pedal. Thus, although a 
particular background accompaniment may consist of a repetition of only 
three or four chords, the musician must know the location of and select 
from all available chord producing keys or pedals. In the Craegar 
arrangement, for example, the three or four chords must be repetitively 
selected from among 65 pedals arranged in five rows of 13 columns each--an 
arduous task for a musician playing a lead melody on another instrument 
with his hands. 
SUMMARY OF THE INVENTION 
The above and other advantages of existing electronic instrument chord 
generating systems are overcome by the present invention which comprises a 
pedal console having a plurality of foot-actuated pedal switches, a switch 
console having a plurality of chord selection switches each respectively 
associated with a pedal switch, and logic circuitry means interconnecting 
the chord selection switch output terminals with the existing tone 
generating circuitry of a conventional electronic musical instrument. By 
appropriate setting of the chord selector switch connected to a given 
pedal switch, the associated pedal can be programmed to produce any chord 
desired. The invention thus permits the musician to vary the musical 
response produced by depression of a set of pedals to simplify the task of 
providing chord accompaniment for a particular musical composition. 
A musical instrument often used to provide chord accompaniment in modern 
musical performances is the electric organ. Conventional electric organs 
are usually provided with two keyboards, commonly known as the "upper 
manual" and "lower manual", and in addition usually include a pedal board 
and a foot-actuated sound volume control. The typical organ further 
includes "stops" which permit selection of various tone qualities for the 
manuals and pedal board. The pedal actuated chord system of the present 
invention permits a musician to fully utilize the conventional electric 
organ in a simplified way that requires little concentration and leaves 
his hands and mind free to exercise his talents on the lead instrument. 
In the embodiment of the invention described herebelow, a pedal board and a 
switch console are provided as accessories for a conventional electronic 
musical instrument such as an electric organ. The pedal board includes a 
plurality of pedals, for example twelve, although any desired number may 
be used. The depression of each pedal actuates an on/off switch that is 
electrically connected to a selected input terminal of a diode matrix 
logic circuit, or other suitable logic/gate arrangement, which in turn 
actuates the existing tone generating circuitry of the associated 
electronic musical instrument to produce the desired chord. The electrical 
connection between the pedal on/off switches and the input terminals of 
the logic circuitry may be selectively varied by means of the switching 
console to permit selection of which chord will be sounded upon depression 
of a particular pedal. The switch console comprises a plurality of chord 
selection switches associated with the pedal switches, each selection 
switch being manually settable by the musician. The switch console 
embodiment described herein utilizes 12 two-deck, 24-position rotary 
switches, one for each pedal, thereby permitting each pedal to sound any 
selected one of 48 possible chords. 
To provide flexibility and to permit greater utilization of the 
characteristics of a conventional electric organ, the described embodiment 
interfaces the output of the logic circuitry with the tone generating 
circuitry of more than one keyboard and more than one octave on a single 
keyboard of the organ. Furthermore, keyboard and octave selection on/off 
switches are provided to permit the musician to select the keyboards 
and/or octaves on which the selected chords will be played. For example, 
in a typical embodiment chords can be played on the upper keyboard first 
octave, upper keyboard second octave and/or the lower keyboard. 
Keyboard/octave switches which affect all pedals can be preset to 
determine which keyboard or octave will sound, or the pedal switching 
arrangement can be modified to give this control on a per pedal basis. The 
illustrative embodiment shows a foot-actuated keyboard/octave selection 
arrangement in which chords can be played on the lower keyboard 
continuously while being "pulsed" on the upper keyboard. This lower 
keyboard sustain feature is provided by the addition of a further switch 
to each of the pedals. Fully depressing a pedal actuates both upper and 
lower keyboard chords, while partially releasing the pedal stops the upper 
keyboard chords but continues the lower keyboard chords until the pedal is 
fully released. 
It is accordingly, a first object of the present invention to provide a 
pedal-actuated musical chord system in the form of an accessory for 
conventional electronic musical instruments such as electric organs and 
which interfaces with the existing tone generating circuitry of 
conventional electronic musical instruments. 
It is another object of the invention to provide a pedal-actuated musical 
chord system as described in which the musical chord produced upon 
depression of any pedal can be quickly changed to a selected one of a 
plurality of chords independently of the other pedal chord settings. 
It is a further object of the invention to provide a pedal-actuated musical 
chord system as described wherein the musical chord produced upon 
depression of any pedal can selectively be varied to include a selected 
one or more keyboard(s) and/or octave(s). 
The above and other objects and advantages of the invention will become 
more readily apparent upon reference to the detailed description of the 
preferred embodiment below and to the accompanying drawings.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
Referring to the drawings, a pedal actuated musical chord system in 
accordance with the present invention is illustrated as applied to a 
conventional electric organ 10. As shown in FIG. 1, organ 10 includes 
upper and lower keyboards or manuals 12 and 14, pedal board 15, sound 
volume control pedal 16, and various stops 18 which control keyboard and 
pedal board tone quality. The organ 10 produces musical tones on either of 
keyboards 12 or 14, or the pedal board 15 when the keys or pedals 
corresponding to those tones are depressed, thereby closing key or pedal 
switches and actuating the connected tone circuits. 
The components of the present invention include a pedal console 20 and a 
switch console 22 which are electrically connected by conductors contained 
in a trunk line 24. As described in detail below, the components of the 
present invention interface with the tone generator circuitry of the organ 
10 by means of logic circuitry which causes simultaneous closing of 
predetermined combinations of organ switches in response to depression of 
the foot pedals of the pedal console. 
The logic circuitry has a plurality of input terminals, each of which upon 
activation produces a particular chord through simultaneous closing of 
certain key switches of the existing organ circuitry. Activation of the 
logic circuitry is brought about by closure of pedal-actuated switches 
located in the pedal console 20 which delivers electrical power to one of 
the input terminals of the logic circuitry. The determination of which 
input terminal will receive the electrical power in response to closure of 
a particular pedal-actuated switch is dependent on the settings of chord 
selection switches located in switch console 22 which serves to 
selectively connect the electrical outputs of the pedal console 20 with 
the input terminals of the logic circuitry. 
As shown in FIG. 2, the pedal console 20 comprises a housing 26 containing 
a plurality of pedals P1-P12, each of which is mounted near one end 
thereof on a horizontal pin 30 for independent pivotal movement. In the 
illustrated example, twelve pedals are arranged in a parallel side-by-side 
array, though any number and arrangement of pedals can be used. The pedals 
protrude outward of housing 26 through apertures 32 spaced along the upper 
surface of the housing. 
A compression spring 34 comprising a piece of resilient foam rubber 
disposed between the base of housing 26 and the underside of pedal 28 
serves to bias the pedal toward a raised position. A stop 36 on the base 
of housing 26 limits the downward pedal movement. The complete depression 
of pedal 28 serves to close a normally open pedal switch PS1 located 
beneath the toe of the pedal and to allow the opening of a normally closed 
sustain switch SS1 located adjacent the heel of the pedal. The partial 
release of pedal 28 permits pedal switch PS1 to open but retains sustain 
switch SS1 in a closed position to provide a sustaining effect as 
described below. 
The trunk line 24 connecting pedal console 20 to the switch console 22 and 
organ 10 may be of such a length as to permit pedal console 20 to be 
operated remotely from the organ. On the other hand, the pedal console 
housing could be constructed so that it can be used in front of organ 10 
by a musician seated on the organ bench without interfering with the pedal 
board 15. 
The switch console 22 includes a front panel 38 on which are mounted 12 
chord selection switches CS1-CS12, each of which is connected with one of 
the twelve pedal switches PS1-PS12. In the present embodiment, the chord 
selection switches are 24-position, two-deck rotary switches. Twelve 
selector switches DS1-12 are located below the rotary switches CS1-12 and 
serve to direct the output from the pedal switches to either the upper or 
lower deck of the rotary switches. 
The rotary switches each have 48 output terminals, 24 on the upper or "A" 
deck and 24 on the lower or "B" deck. Each of these outputs serves as an 
input to the logic circuitry that interfaces with the tone generating 
circuitry of organ 10. Thus, for each pedal 28 of pedal console 20 the 
corresponding chord selection switch can be manually set by the user to 
any one of 48 possible positions. Since each position of selector switch 
CS1 corresponds to a different input to the logic circuitry of the chord 
selector, any one of 48 possible chords can be played by each pedal. 
Keyboard/octave switches OS1-OS4 located at the left side of the switch 
console front panel 38 control which keyboard(s) or octave(s) of the organ 
10 will sound when the pedals are depressed. Switch OS1 controls a first 
octave of the upper keyboard, OS2 the second octave of the upper keyboard, 
OS3 the lower keyboard and OS4 the sustain feature utilizing the lower 
keyboard. A more detailed understanding of the functioning of the logic 
circuitry and switching network of the illustrative embodiment can be 
gained from the block diagram shown in FIG. 3 and the partial schematic 
diagram shown in FIG. 4. Portions of the circuitry are omitted from the 
schematic of FIG. 4 to simplify the presentation and to permit a larger 
scale view of the illustrated portions of the circuit. 
Power for the chord selector operation is supplied by any conventional DC 
power supply. For example, as shown in FIG. 4, the power supply may 
comprise a transformer T1 whose primary coil is connected to a standard 
110 volt AC power supply and whose secondary coil is connected to a full 
wave diode bridge rectifier to provide 24-volt DC power input to the pedal 
switches. The positive side of the 24-volt DC power supply is connected by 
conductor 40, which passes through fuse F1, to one side of each of pedal 
switches PS1-PS12 and each of sustaining switches SS1-SS12 through a 
connection system that serves as an electrical priority interlock so that 
only one pedal switch and sustaining switch pair can be actuated at one 
time, i.e. two chords cannot be played at once. The interlock circuitry of 
FIG. 4 gives priority to the right hand pedal of a pair or group of pedals 
which are simultaneously depressed. 
For references purposes, the 12 pedals illustrated in FIG. 4 are numbered 
P1 through P12 from left to right. The common center terminal C of 
switches PS 12 and SS 12 of pedal No. 12 is connected to the positive 
terminal of the power supply directly through conductor 40. The common 
center terminal C of switches PS 11 and SS 11 of pedal No. 11 is connected 
to the positive side of the power supply through terminals A and C of 
switch SS 12 of pedal No. 12 and the conductor 40. The common center 
terminal C of switches PS 10 and SS 10 of pedal No. 10 is connected to the 
positive side of the power supply through terminals A and C of switch SS 
11 of pedal No. 11 and through terminals A and C of switch SS 12 of pedal 
No. 12 and then through conductor 40. Likewise, each of the center 
terminals C of the pedals Nos. 1-9 are connected through the terminals A 
and C of the sustaining switches of all the proceeding pedals to the right 
of it and through conductor 40. When any pedal No. 1-12 is depressed to 
play a chord the corresponding sustaining switch is actuated to provide 
connection between terminals B and C of that switch and thereby break the 
electrical connection between terminals A and C of that switch. Thus, 
depressing a pedal locks out all electrical connections to the power 
supply of pedals to the left of the depressed pedal. 
When any one of pedals P1-P12 is depressed, the associated pedal switch 
PS1-PS12 and sustaining switch SS1-SS12 are closed. This provides 
electrical connection between the positive side of the power source and 
deck selection switches DS1-DS12 and rotary chord selection switches 
CS1-CS12. It also provides electrical connection of the buss conductor 64 
to the power supply. 
Each of switches CS1-CS12 has 24 positions which are referenced Nos. 1 
through 24 beginning at the 12 o'clock position and continuing clockwise 
around the dials. The 48 output terminals of each two-deck, 24-position 
rotary switch are connected to 48 input terminals of the chord selector 
logic circuitry. Since each input terminal to the chord selector logic is 
preset to actuate a different chord or note combination on the electronic 
organ circuitry, the user sets the switches DS1-DS12 and CS1-CS12 to 
select the desired one of 48 available chords he wants to sound for each 
of the pedals. When a pedal is depressed the positive side of the power 
supply will be connected to the user set chord selector logic input 
terminal and the desired tone generation circuits will be activated. 
Common logic circuitry input terminals are connected by means of busses to 
the identically numbered output terminals of the two decks of chord 
selector switches CS1-CS12. Accordingly, if all switches DS1-DS12 and 
CS1-CS12 were to be set to the same position, pedals Nos. 1-12 would all 
play the same chord when depressed. As shown in FIG. 4, all deck A 
position #1 settings of switches CS1-CS12 are connected together by a 
common bus conductor 44. Similarly, although not shown, each of the other 
47 switch settings are interconnected to produce the same chord on the 
same number setting for any selected pedal. For example, if the #1 A deck 
setting produces a C major chord for each pedal, the #2A deck setting 
might produce a C minor chord, #3 a C augmented chord, etc. Other 
switching arrangements can be substituted for switches DS1-DS12 and 
CS1-CS12 to perform the same function of channeling the output of pedal 
switches PS1-PS12 to logic input terminals. Also, the selection of 
available logic input terminals to which the outputs of switches PS1-PS12 
are channelled do not have to be the same. However, utilizing common chord 
selections for each chord selection switching network provides the most 
flexibility and simplifies the circuitry. 
The logic that connects the output terminals of switches CS1-CS12 to the 
activation of combinations of key switches on the keyboards of organ 10 
can be digital logic circuitry, i.e. AND, NAND, OR and NOR gates, or can 
be diode matrix logic comprising direct matrix wiring of input terminals 
to components, such as electromagnetic relays, that activate the relevant 
key switches. The logic circuitry of the illustrated example comprises 
chord diode logic matrices. 
To illustrate the connections and components constituting such diode logic, 
FIG. 4 shows the schematic circuitry for a C-major chord selection for 
pedal P1 which is obtained by setting deck selector switch DS1 to the "A" 
deck setting, and chord selection switch CS1 to the #1 setting. Full 
depression of pedal P1 closes pedal switch PS1 which connects the positive 
voltage from contact C of switch SS1 to a conductor buss 46 through 
switches DS1 and CS1. The application of positive voltage to the anode 
electrodes of diodes D5-D10 renders them forward biased for conduction of 
the positive voltage to conductors 48, 50 and 52 of the upper keyboard 
chord logic circuitry and to conductors 54, 56 and 58 of the lower 
keyboard logic circuitry. This likewise applies the positive voltage to 
the anode electrodes of diodes D11-D22 as shown. 
Keyboard/octave switch OS1 serves when closed to connect the cathode 
electrode of diodes D11-D13 to electrical ground. When switch OS1 is 
closed, current flows through gates such as electromagnetic relays K1-K3 
which close key switches KS1-KS3 which in turn actuate the tone generation 
circuitry of the first octave of the upper keyboard to produce a chord 
comprising the notes C, E and G. Switches KS1-KS3 can be activated 
directly by relays K1-K3 as shown, or relays K1-K3 can be used to close 
auxiliary switches (not shown) wired in parallel with the switches 
KS1-KS3. 
Likewise, when keyboard/octave switch OS2 is closed, current flows through 
relays K4-K6 which close key switches KS4-KS6 of notes on the second 
octave of the upper keyboard to produce the notes C', E' and G', as shown 
in FIG. 4. And, when keyboard/octave switch OS3 is closed, current flows 
through relays K7-K9 which closes key switches KS7-KS9 of keys on the 
lower manual keyboard of organ 10 corresponding to notes C", E" and G", as 
shown in FIG. 4. 
Similar circuits are provided for every other input terminal of the chord 
selector logic matrices. For example, consider position No. 2, deck A of 
switch CS1 to be a C minor chord. A common buss conductor (not shown) 
connects all positions Nos. 2, deck A for switches CS1-CS12. This buss 
then supplies positive voltage biasing to the anode electrodes of diodes 
(not shown) whose cathodes are connected to buss conductors 48 and 54 to 
produce the C, C' and C" notes, to buss conductors 52 and 58 to produce 
the G, G' and G" notes, and to buss conductors 60 and 62 to produce the E 
flat, E' flat, and E" flat notes. Although not shown, the full circuit 
will comprise at least twelve busses such as 60 and 62 for each keyboard 
to supply the necessary key switch actuation. 
When keyboard/octave switch OS1 is closed, chords will be sounded in the 
first octave of the upper keyboard. When switch OS2 is closed, the chords 
will be sounded in the second octave of the upper keyboard. And, when 
switch OS3 is closed, chords will be sounded in the lower keyboard. One, 
any two, or all of switches OS1-OS3 can be closed as desired to change the 
qualities of the sounded chords. 
The diodes' function in the matrix is to keep the direction of current flow 
in only one direction along the paths in which the diodes are placed. In 
the illustrative embodiment, every output terminal chord setting on switch 
CS1 that includes a C, for example, to be played on the first register of 
the upper keyboard will be connected from the respective output terminal 
on CS1 to a buss conductor connecting similar output terminals of switches 
CS2-CS12. The diode connections serve as columns in the upper keyboard and 
lower keyboard matrices electrically connecting the respective output 
terminal busses to the busses such as conductor 48 which form the matrix 
rows connecting to the key switch actuating relays. Without the use of 
diodes, depressing pedal P1 with switches DS1 and CS1 closed would close 
all key switches of notes contained in chords having C's, E's or G's in 
them. 
Capacitors C1-C6 of 0.1 microfarad are used to connect the busses 48-62 to 
ground to eliminate electrical spikes and other variations in the DC 
voltage. Such capacitors have no effect on the DC voltage in the busses, 
acting as open circuits to the DC signal. Similarly, capacitors C7-C10 are 
connected across switches OS1-OS4 for the same purpose. 
The closing of keyboard/octave selection switch OS4 activates the lower 
keyboard chord sustaining mode of the invention. When one of the twelve 
pedals P1-P12 is depressed, the corresponding sustaining switch SS1-SS12 
is closed thereby connecting buss 64 to the positive side of the power 
source. When switch OS4 is closed and pedal P1 is depressed with the chord 
selection switches set as shown in FIG. 4, current flows through relays 
K7-K9 to close key switches KS7-KS9 which sound the lower keyboard notes 
C", E", and G". However, locking relays K10-K12 are also energized, and 
act to close relay sustain switches RS1-RS3. Partial release of pedal P1, 
opens switch PS1 but keeps switch SS1 closed. Chords sounded on the upper 
keyboard are thus cut off by the partial release of the pedal, but relays 
K7-K9 which close key switches on the lower keyboard are still energized, 
being connected to the positive terminal of the power supply through 
closed switches RS1-RS3 and switch SS1. Key switches KS7-KS9 remain closed 
until pedal P1 is completely released, thereby opening sustain switch SS1. 
If the sustain mode is not desired, switch OS4 is opened, preventing 
energization of relays K10-K12 and the closing of switches RS1-RS3. By 
manipulating a pedal alternatingly from a fully depressed position to a 
partially depressed position, the pedal switch (PS1-PS12) will 
alternatingly open and close, but the sustain switch (SS1-SS12) will 
remain closed to sustain the chord sounded on the lower keyboard and pulse 
the chords on the first and second registers of the upper keyboard. 
For organs producing tones by the use of an air compressor or drum, a 
foot-actuated on/off switch MS1 can be located on the foot pedal console 
20 adjacent to one of the end peddles. The switch MS1 is preferably of the 
type that turns on with one depression and turns off with a second 
depression. Closing MS1 actuates relay MK1 which closes drum switch MS2 on 
organ 10. The foot-actuated switch permits the drum to be turned off by 
the performer when the chord accompaniment is not needed and turned back 
on when required. 
The pedal-actuated musical chord system invention permits a musician to 
provide musical accompaniment in the form of chords played on an 
electronic musical instrument by simple depression of a few foot pedals on 
a pedal console that can be used remotely from the electronic instrument. 
The chord responses obtained by depression of each pedal can be selected 
from a multiplicity of possible chords. For example, to play a chord 
accompaniment to a guitar melody requiring C major, F major, E major, and 
D minor chords, the guitarist need only use four foot pedals. The chord 
selection switches could be set so that pedal P1 will play a C major 
chord, pedal P2 an F major chord, pedal P3 an E major chord, and pedal P4 
a D minor chord. Thus, while playing a guitar with both hands, a musician 
can with one foot and with little training provide his own accompaniment 
with the full range of instrument sounds available through the stop 
settings of an electronic organ. The musician further can choose to 
provide chords from the lower keyboard, upper keyboard first octave, or 
upper keyboard second octave in any desired combination. As an additional 
option, the sustain feature can be employed to permit interruption of the 
upper keyboard chord while sustaining the chord on the lower keyboard. 
Manifestly, changes in details of construction can be effected by those 
skilled in the art without departing from the spirit and scope of the 
invention.