US2792738A - Fretted electronic musical instrument - Google Patents

Description

w A. DONAHUE FRETTED ELECTRONIC MUSICAL INSTRUMENT 2 Sheets-Sheet 1 Re m M 3 W3 m r/M r-- .3 w 1 w -i A, a L 2 u\=/m =k a v o o o V Z a f: n u i W 7. m m w a w May 21, 1957 Filed April 28, 1954 May 21, 1957 w. A. DONAHUE FRETTED ELECTRONIC MUSICAL INSTRUMENT '2 Sheets-Sheet 2 ffvENTo i I n i j aamua mmmszmma a EIMEEEPGEEEEEQ 15a Filed April 28, 1954 60 Willi am A 110 1 a]; ue

BY Mj m% ATTD RN EYE United States Patent FRETTED ELECTRONIC MUSICAL INSTRUMENT William A. Donahue, Newark, N. J.

Application April 28, 1954, Serial No. 426,207

1 Claim. (Cl. 84-267) This invention relates to a musical instrument, and more particularly to an electrical finger board for musical instruments such as a guitar, banjo, mandolin, ukulele, zither or an electrical guitar.

The object of the invention is to provide a musical instrument which has a novel finger board whereby the instrument can be played with one hand by pressing the string down instead of plucking or picking the string.

Another object of the invention is to provide a musical instrument which can be played either as a natural guitar or as an electric guitar with amplified sound, or as an electric guitar with electronic sounds.

A still further object of the invention is to provide an instrument for use by persons who have lost one of their hands in accidents or in war.

Another object of the invention is to provide an instrument which can be played with one hand so as to permit the other hand to play another instrument such as a drum, harmonica, piano or the like.

A still further object of the invention is to provide an electric guitar which can be played by either a person who is right or left handed and wherein the instrument is played simply by pressing the string down on the contact to produce the note so that no picking of the string is necessary.

A further object of the invention is to provide a musical instrument which is extremely simple and inexpensive to manufacture.

Other objects and advantages will be apparent during the course of the following description.

In the accompanying drawings, forming a part of this application, and in which like numerals are used to designate like parts throughout the same:

Figure l is a plan view of the musical instrument, constructed according to the present invention.

Figure 2 is an enlarged top plan view of the finger board.

Figure 3 is a bottom plan view of the finger board.

Figure 4 is a sectional view taken on the line 4-4 of Figure 3.

Figure 5 is a sectional view taken on the line 55 of Figure 4.

Figure 6 is a wiring diagram showing the finger board and amplifier.

Figure 7 is a bottom plan view of a modified finger board wherein six notes can be played or produced at one time.

Figure 8 is a fragmentary wiring diagram for use with the finger board of Figure 7.

Referring in detail to Figures 1 through 6 of the drawings, the numeral 10 designates a guitar having a body member 11 and a finger board 12. The musical instrument 10 further includes a potentiometer 14, an on and oil switch 15, and a bridge 16.

Extending longitudinally along the top surface of the finger board 12 is a plurality of wires or strings 17, 18,

19, 20, 21, and 22, Figure 1. These strings 17 through 22 are adapted to be manually pressed down instead of being plucked or picked and these strings may be made of any suitable conducting material such as steel. A tailpiece 24 is provided, and all six strings 17 through 22 are grounded to this tailpiece and also to a cable jack 25. The cable jack 25 is electrically connected to the finger board and is also connected to the potentiometer 14 and switch 15. The finger board itself is made of a non-conducting material such as wood or plastic. The opposite surface of the finger board 12 is provided with a plurality of longitudinally extending grooves or recesses 23, Figures 3 and 4.

Extending upwardly from the finger board 12 is a plurality of frets 26 which are adapted to be contacted by the strings 17 through 22 when the strings are manually depressed. These frets 26 are held securely in place on the finger board by suitable securing elements such as the bolts or rivets 27, and the bolts 27 include heads that are arranged in the grooves 23. In Figure 2, the top of the finger boardis shown by itself with only the frets 26 in place. In Figure 3 the bottom of the finger board is shown. A plurality of resistors 28 are positioned in certain of the grooves, and these resistors are electrically connected to certain of the frets through the medium of conductors or wires 29. The grooves 23 are defined by wall sections 30, Figure 4, and each of these wall sections 30 are provided with a plurality of cutouts or slots 31. A first set of jumper wires 32 are indicated by dotted lines in Figure 3, and these jumper wires 32 extend through certain of the slots 31. A second set of jumper wires 33 extend through other of the slots 31. The wires 33 are used to duplicate the note in the row of resistors at the point where they are soldered to the contacts.

Referring to Figure 6 of the drawings, there is shown an amplifier for use with the musical instrument of the present invention. The amplifier includes a power supply 35 wherein A. C. current comes in through a power transformer 36 and this current is rectified by a rectifier tube which may be a 5Y3 type of tube. The voltage is stepped up from 13 plus throughout all circuits.

There are three tubes 37, 38 and 39, and tube 37 is the audio-oscillator tube that sets up oscillation in a well known manner. In oscillating tube 37, there is an oscillating frequency from plate 40 to grid 41 at an audio rate. The frequency of the audio signal that is oscillating between the plate 40 and the grid 41 can be varied by varying the grid resistance.

The potentiometer 14 is merely for tuning the circuit.

-In the present invention, the grid resistance of the tube 37 is varied by manually pressing the strings 17 through 22 intocontact with the frets 26 and this varies the frequency of the tube 37 itself by throwing in various resistances. Once the desired frequency is established in the oscillating tube 37, it is amplified through tubes 38 and 39, and the amplified sound is emitted through the loud-speaker 42. Thus, as the resistance is changed by pressing the strings 17 through 22 at diiferent places, the frequency of the signal is changed. There is further provided a gaseous rectifier 43 which provides plate voltage to the oscillator tube 37. With the present invention, the resistance is changed according to the desired note in order to vary the grid resistance or bias.

In use, and referring to Figure 6 of the drawings, any of the strings 17 through 22 can be manually moved into engagement with any of the frets 26 by pressing the strings downward. Each of these frets 26 corresponds to a musical note such as A, D, G, C, E, All, Di, and Gt and the like. The resistors 28 are connected in series with the frets. Thus, by engaging different notes or I quency pitch.

3 frets 26 with the strings, the grid resistance of the tube 37 will be varied to thereby vary the frequency of the tube 37 itself since different numbers or amounts of resistors 28 will be thrown into the circuit and these varying sounds will be amplified and emitted by the loudspeaker 42.

Referring to Figures 7 and'8 of the drawings,'there-is shown a modified arrangement wherein the finger board is indicated generally by the numeral 44. Figure '7 shows the undersurface of the finger board 44 which is provided with a plurality of spaced parallel wall sections 45 that define grooves 46 therebetween. Frets Sfi may be secured to the finger board in any suitable manner, *as for example by bolts or securing elements 47. 'Re'sistor's 48 are connected in series to the securing elements-47, and the resistors 43 are seated in'the grooves46. Itfwill be seen in'Figure 8 that lines'49 connect'certainofthe frets 50 to a complete oscillating amplifying unit 60. Thus, thelines 49 are adapted to be each connected to an oscillating amplifier such as the amplifier shown in Figure 6. The numerals 51, 52, 53, 54, 55, and 56 designate the strings of the musical instrument which are adapted to be manually depressed to engage the frets 50.

With the arrangement shown in Figures 7 and 8, the user can play six different notes at one time which is now'an instrument such as an organ, piano, accordion or other instrument is played wherein more than one note is played at one time in order to play a chord melody.

"However, in the arrangement shown in Figures 7 and 8 "six oscillating amplifiers are required to produce the six 7 notes at one time, and these six oscillating amplifiers are connected to the finger board through the lines 49. Also,

in this modified arrangement if desired the user can play one note at a time so that if you press only one string tothe contact fret 50, you get one note. Similarly, if you press two different strings down you get two different notes, and if you press three different strings down you get three different notes so that all six strings can be actuated at one time.

From the foregoing it is apparent that there has been provided a musical instrument such as an electric guitar 'notes together.

In Figures 7 and 8 six oscillating amplifier units are used and one unit is required for each row of contacts with the resistors between using the string above for ground. The jumper lines'32 connect the resistors 28 in acontinuous line or as a series circuit. The other jumper lines 33 are used to duplicate the same frequency pitched note to the other contact frets that they are pumped and soldered to. All notes soldered to each jumper wire and contact fret must be the same fre- In the arrangement shown in Figures -1 through 6, only one note at a time can be played on an instrument whereas in the arrangement shown in Figures 71and 8 six different notes at one time can be played. In Figure 8 a common ground line 57 is provided for all the six oscillating amplifiers. The cable jack is grounded or Wires 33 interconnect adjacent notes or'frets 'which are" similar. The printed letters in the blocks shown in "Figure6 are thenames of'theno'tes that each contact or fret represents and by starting at any contact, it will be 'EA, NO. in Figure 8). controls, onefor each of the six oscillating units used in noted that the jumper wires connect the same note in the contact blocks. The wires are concealed in the body of the instrument and in the finger board 12. The potentiometer 14 is used for setting the frequency pitch of a note in the instrument. The cable jack 25 connects the oscillating amplifier to the common ground tailpiece 24 and to the strings 17 through 22 on the instrument. The line 53 goes to the bottom contact of the finger board as shown in Figure 6 or to all six bottom contacts if an arrangement such as that shown in Figures 7 and 8 is used.

The finger board is made of a material that will not conduct electricity and can be made of any suitable material such as wood, plastic, or composition material. The upper surfaces of the frets 26 are rounded as shown in Figure 5 so that the guitar can be played in the usual manner without using the electrical system. Then, by disconnecting the amplifier, the guitar can be played to .produce a straight natural sound. Also, the instrument can be. played as an electric guitar with amplified sounds or with electronic sounds. The switch 15 can be used 'tocut the amplifier on or off. The number of resistors used can be varied as desired, and-also the values of these resistors can be changed. The amount of resistors in the circuit determine the given note frequency going into the oscillator tube 37 and the arrangement of the oscillating units can be varied as desired.

Without any electrical system and using the present invention it is necessary that the strings be first pressed to the frets and plucked to produce the sounds. With applicants finger board and oscillating amplifier, it is only necessary to press the string to the contact fret and the note will be produced without plucking the string. As long as the string is held to the contact frets the notes will keep sounding out, and this is only possible with the finger board of the present invention, since in other instruments the sound dies away after plucking.

There are two potentiometers shown in Figure 6, and one of the potentiometers is used to tune the 440 cycles the numeral 61 and is used as a volume control for the oscillating amplifier in Figure 6.

In Figures 7 and 8 there are twelve potentiometers because there are six individual strings and six oscillating amplifier units. Six of these potentiometers are used to tune the bottom-most note of the six strings (A D G C The other six are volume the Figures 7 and 8 system. These potentiometers that are used to tune the above notes may be in either the instrument or placed in the oscillating amplifier cabinet if desired, since by placing them in the cabinet they will be out of the Way and will not be knocked or bumped. In Figure 6, preferably the one potentiometer used to tune the A note would be most conveniently placed in the in tiometers for the Figures 7 and 8 system, preferably these potentiometers are placed in the oscillating amplifier cabinet so that the instrument can be tuned from the cabinet without fear of hitting the potentiometers and knocking the six units out of tune.

The finger board may be secured to the body member by various methods such as by using screws which go through the finger board 12 at the points indicated by the numeral 62 and these screws may go into the body member 11. These screws hold the finger board in the correct position and may also act as position marks to indicate the first, third, fifth, seventh, ninth, twelfth, fifteenth and seventeenth positions. Also, the finger board can be glued to body member.

The theory and functioning of the system shown in Figures 7 and 8 is the same as that shown in Figure 6 broadly. Thus, the same components that are used in Figure 6 are also used in Figures 7 and 8. Figure 6 shows one complete circuit of components which includes the finger board with forty-one resistors in series, one single pole single throw switch 15, one potentiometer 14, one oscillator-amplifier 63, one speaker 42, one tailpiece 24 with the six strings 17, 18, 19, 20, 21 and 22 grounded to it. The Figure 6 system makes it possible to play any one of forty-two notes but only one note can be played at a time. The jumper wires 32 connect the first extreme right row of contacts and resistors with that of the second, third, fourth, fifth and sixth rows.

In Figures 7 and 8 there must be six complete and separate circuits and each of these six circuits are the same as the one complete circuit of Figure 6. With the set-up shown in Figures 7 and 8 a person can play one note, two notes, three notes, four, five or six notes at a time depending upon how many strings are pressed to the contact frets 50. Also, any of the six strings can be cut out from playing electronically by using a single pole single throw switch and then the strings will play or sound out with the amplified tone of the guitar to provide a novel effect and tricky efiects can be produced with the tone and color controls of each circuit. In other words, the simulated sounds of six different instruments playing at one time can be produced. In Figure 6 the numeral 63 designates the complete oscillator and amplifier circuit. Figure 6 requires one of these oscillator and amplifier circuits 63 while Figures 7 and 8 require six of these same units.

In Figure 6 one oscillator-amplifier 63 is used to produce all the individual notes possible on the finger board because the finger board is so wired that only one note can be played at a time. Thus, if only one note can be played at a time only one oscillator-amplifier to produce this one note is required. Further, no matter how many times this note is changed to a different note, there will still only be heard one note at a time. For example if a piano is played with one finger, it can be played as fast as possible but still only one note can be heard and this one note is produced each time the key is struck with the one finger and that idea is the same as shown in Figure 6. Thus, every note on the finger board can be played but only one at a time. However, in Figures 7 and 8, more than one note can be produced at a time and in Figures 7 and 8 the finger board is broken up into six individual sections and each section will take care of eighteen individual notes. To each section of eighteen notes there is connected one oscillator-amplifier to produce any one of the selected notes out of the eighteen. Thus, in Figure 7 there are six rows of resistors but there are no jumper wires in the Figure 7 set-up. To each row of resistors there is connected one oscillatoramplifier to produce any of the notes in that particular row and if a string is pressed down and makes conatct with the fret in a particular row, then the signal goes through the resistors in that row and to the corresponding amplifier and then out through the speaker such as the speaker 60. In Figures 7 and 8 there are six complete individual units built into one general unit and each unit comprises one string, eighteen contact frets, seventeen resistors, one On and Ofi switch, one potentiometer to adjust the pitch of the bottom-most note, and one oscillating amplifier with speaker. There are six of these units, one for each of the rows of resistors in Figure 7.

The wires 33 interconnect adjacent notes or frets. It is to be understood that the person using the present invention need not buy a new amplifier since the persons present amplifier can be converted with the addition of two or more tubes, one transformer, a few resistors and condensers. With the addition of these parts the persons amplifier will be able to play the instrument of the present invention through it and a conversion unit can be sold cheaply and with such a conversion unit any public address system or amplifier can be used. If a person does not want tone and color ranges, a conversion unit can be provided at a very cheap price in other words a persons present amplifier can be very easily and cheaply converted so that it will use the present invention, and any amplifier can be converted to play the present instrument.

I claim:

In a musical instrument, a body member, a finger board extending from said body member, a plurality of strings extending longitudinally along the top surface of said finger board and said strings adapted to be manually pressed downward, a tailpiece having said strings grounded thereto, a cable jack electrically connected to said finger board, said finger board being made of a non-conducting material, there being a plurality of longitudinally extending grooves in said finger board, a plurality of frets extending upwardly from said finger board and adapted to be contacted by said strings, securing elements for holding said frets in place on said finger board and said securing elements including heads seated in said grooves, a plurality of resistors positioned in certain of said grooves, wires connecting said resistors in series to certain of said frets, said grooves being defined by wall sections, each of said wall sections being provided with cutouts, said frets corresponding to musical notes, and jumper wires extending through said cutouts and connecting similar notes together.

References Cited in the file of this patent UNITED STATES PATENTS 1,847,119 Lertes Mar. 1, 1932 2,070,344 Waters Feb. 9, 1937 2,528,663 Mitchell Nov. 7, 1950

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