US2510094A - Musical instrument - Google Patents

Description

June 6, 1950 FLEURY 2,510,094

MUSICAL INSTRUMENT Filed May '25, 1946 2 Sheets-Sheet 1 Igj 1%. 2"

Inventor 5/) man 0. Fla/RY Qwaoria Wyn we; 3m 1 June 6, 1950 E. o. FLEURY 2,510,094

MUSICAL INSTRUMENT Filed May 25, 1946 2 Sheets-Sheet 2 G u 57 7? 72 56 a 5 o 6 6 =$F a4 Aumo T 4 AMPLIFIER llll'wltor Ear/s75 0. F 1. gum

Patented June 6, 1950 UNITED STATES PATENT OFFICE 6 Claims.

This invention relates to musical instruments, and more particularly to musical instruments op erated by keys. The principal object of the invention consists in providing a musical tone or note producing unit which, when operated, gencrates electrical oscillations of the exact frequency corresponding to the musical tone or note associated with the key. These electrical oscillations may then be used to operate an electroacoustic sound production system.

A further object of the invention consists in providing a unit of the type mentioned which produces the electrical oscillations by means of a reed or flat spring having a natural frequency with which it will oscillate, if receiving impulses either directly or by using its inertia. The natural frequency of a reed is defined very exactly and therefore permits to obtain clear tones.

A still further object of the invention consists in making the reed operative by placing it into a magnetic circuit in alignment with a core carrying a coil, the said two members serving to close said magnetic circuit completely with the exception of a small gap left between them. Preferably the cross sections of the reed and the core facing each other on both sides of said gap are approximately the same so that the vibration of the reed will cause a regular or sinusoidal variation of the magnetic flux, and of the current induced thereby in the coil carried by said core.

A further object of the invention consists in providing a musical instrument, using the aforesaid units for producing electrical oscillations of a frequency corresponding to a definite musical tone or note, in which the keys allotted to each musical tone or note are operating a mechanism provided with a striking member or a mechanism adapted to impart a rapid movement to one of the units, which movement is automatically and suddenly arrested. In the first case the vibration is caused directly by the impact of said striking member on the vibrating reed, while in the second case the inertia of the reed causes vibration with natural frequency. The movement of the striking member or of the movable member supporting the above described unit may either be produced by means of a so-called action or it may be produced by attaching the note producing units directly to the keys.

A still further object of the invention consists in providing a volume control of the sound pro duced which may be either mechanical and may consist in means for regulating the damping of the oscillations of the reed or may be electrical, the latter method being preferable in cases in which mechanical control entails constructive difficulties or in which the sound volume control is intended to be carried beyond the limits within which mechanical means will operate.

Further objects will be apparent from the following detailed specification describing several embodiments of the invention. It is to be understood that these embodiments are examples for illustrative purposes and are not intended to be limitative. The invention is described in such terms that the expert skilled in this art will readily understand that certain details and constructional features are subject to change without in any way departing from the invention.

In the accompanying drawings:

Figures 1 and 2 are elevational side and front views, respectively, of a single tone producing unit according to the inveniton.

Figure 3 is a cross sectional plan view of said unit, the cross section being taken along the line 33 of Figure 1.

Figure 4 is an elevational side view of one embodiment of the invention using the so-called action now used for Striking the piano strings and for damping the oscillation for operating the tone producing units according to the invention.

Figure 5 is an elevational side view of a modification of the action specially adapted for the purpose in question.

Figures 6 and '7 are elevational side views similar to those of Figures 1 and 2 showing units used for the highest tones.

Figure 8 is an elevational side View of the back board of a piano with the tone producing units shown in Figures 4, mounted thereon.

Figure 9 is an elevational side view of another tone producing arrangement in which no action at all is used, the tone producing unit being directly attached to the keys of the piano.

Figure 10 is a diagram showing the general arrangement and the electric connections of the modification illustrated in Figure 9 or in Figure 5.

Figure 11 is an elevational view of a complete piano, illustrating the arrangement of the main components.

In order to explain the object of the invention in general terms, it may be mentioned that it is the main purpose of the invention to produce electrical oscillations corresponding exactly to the musical tone which is allotted to each key of the piano or other musical instrument. While the keyboard and the operational method of producing music by depressing keys corresponding to 3 certain notes remains essentially unchanged, the oscillations directly produced by the keys are not sound vibrations but are electrical oscillations which may be reproduced in the usual manher by a loud speaker, by a telephone or the like or may be recorded in the well known manner. This electrical reproduction method permits a far better regulation of the volume of sound deliv-- ered and it may even be used-in the event that music is practicedin such a way that merely the operator, or a selected number of persons, is enabled to hear the music produced; a result which is easily obtained by using earphones. Conversely, a piano of the type described maybe used with a volume of sound which exceeds by far that which can be produced by 'the'convem tional type of piano, so that music for a large open air audience, dance music for open air, or for a plurality of rooms, etc., may be produced individually without the intermediation of a pub lic address system which, as a rule, is imperfect from a musical point of view.

The main element of the invention consists in the tone producing unit l2, allotted to each key of the piano or other musical instrument, which replaces the piano string conventionally used.

This unit consists of a flat spri or d I4 of a predetermined length attached to a frame T6 of magneticallypermeable material, which is closed on three sides and openat the fourth side. This open side is partly closed by the reed I l and partly by a core 15 "of magnetically permeable m'ateria'lprojecting from the frame towards the spring. Onlya smallgap Ill-is left between these two parts. The core may be bevelled so that it tapers toward the edge l8 facing the reed M. The magnetic linesof force arethus concentrated in a zone corresponding to the cross section of the spring.

'The' reed may, if necessary, be loaded by a weight l9. It is fixed at one end on "the frame [6 by means of a screw 28. A reed or flat spring attached at one end has, as well known a very 1 exactly defined natural frequency or resonance 7 frequency, determined by its own free length, if not loaded, or'by the distance of the center of gravity of the oscillating system from the point of attachment, if loaded. The reed or spring of each unit is, therefore, so selected that its nat ural frequency corresponds to that of the musical tone or note to be produced by one key.

The core I5 is surrounded by a coil 22 provided with fine windings, the wire leading toand from said coil being indicated at 23, 24.

The frame is preferably laminated'and 'consists of a large number of lamellae. is magnetized so as to form a magnet.

Said frame tional mechanism, called action, may be used as illustrated in Figure 4. The units 12 may be aligned along the back board 25 of the piano or other instrument as no resonance board or the like is necessary (see Figures 4 and 8).

These units as is seen' differ as regards the free length or the reed and the length of the frame I 6 varies 'tion of rest by a spring 56.

correspondingly. However, the cores l5 and coils 22 are preferably the same for all spring lengths.

The conventional action such as shown in Figure 4 need not be described in detail as the mechanism is identical with the standard mechanism now used. It comprises the hammer 26, the check El, cooperating with the back stop 28, the Wippen 29, the prolong 30, cooperating with the capstan screw 31 directly operated by the key lever 32 which forms a continuation or projection of the key 35 which turns around the balance rail 36.

The damping mechanism again is practically identical with the damping mechanism as conventionally used and comprises the damper block 39, the head ll of which is applied against spring i i of the unit I 2, much in the same way in which it is usually applied against the piano string.

The conventional action now in use which was developed for piano strings, although suitable to operate units according to the present invention may, however, be simplified to a marked degree.

'This simplification is shown in Figure 5 in which the back board does not carry the units but is provided with the check All which in this case consists of a wedge-shaped member lined with felt .2. It also carries a rail M which supports two pivot pins 45, 46. The prolong 48 which cooperates with the capstan screw 3! and key lever 32 in the way shown in the lower part of Figure 4 marked by reference'letter'a, is provided with two further pivot pins 49, 50, and is linked to the rail a l by means or links 5!,52, turning around the pivot pins 59, 50 andt5y46.

Thus a lever parallelogram is formed which will keep the prolong 38 in its vertical position while moved by the key. The link 52 may form part of or may be connected with a bracket 5 extending upwardly from the lever parallelogramand carrying the note or tone producer unit I2.

The damping mechanism in this case is operated by the pedal rod 56, which is connected with "pins 58.

'Each action lever 59 carries a damper wire 6| at the end of which the damper block 62 is attached. The block62 carries the damper head '63 made of suitable material such as a piece of fur of piled fabric and the like which is to be applied against the reed I4 of the unit l2.

The action leverfit is pivoted at 64 on'a stationarysupporting rail (55 and is held in its posi- The'supporting rail may project towards the bracket 54, and may be provided with an end surface 6'! whichis parallel to the bracket as. when at rest and is heavily lined with felt 68 in order to form a back 'stop'for the moving parts of the mechanism.

It will be clear from the above that the downward movement of key causes an upward movement of capstan screw 3i and of prolong 58 which will move the bracket 54 against the back wall 35. This movement is suddenly stopped by the felt 52 on member the reed M of the unit i2, therefore, starts its oscillations which will last until the bracket 54 falls back. When the bracket returns the starting of a new "series of oscillations is effectively prevented by the back stop felt 61.

The oscillations of the reed are effectively clamped by damper head Gi held against the reed 51 is moved and lifts the damper head from the reed M.

A further simplification of the arrangement results if the note or tone producing units i2 are directly fixed on the keys 35 as shown in Figure 9. Preferably the units are fixed on the keys between the keybed frame 68 and the balance rail. Each key is, as usual, provided with a stop pin 69 striking against a felt pad is on the keybed frame 68. To increase the force necessary to move the keys and to make it equal to the force necessary to move a key against the resistance of the action now in use, th ke levers 32 may be loaded by means of weights (now shown).

The means for translating the electrical oscillations into sound oscillations are shown in Figures and 11. This Figure also shows an electric volume control of the tones which may be i applied instead of the mechanical volume controls produced by damping in those cases in which the introduction of a mechanical control entails constructional complications.

In Figure 10, the coils 22 are all arranged in series although other connections would be possible likewise. These coils form part of a circuit 10 which may or may not be provided with an amplification stage and which is closed by the step up transformer ii. The secondary 72 of the transformer is connected in series with two resistances l5 and which are provided for volume control purposes. The entire circuit I! con taining the said elements forms the input circuit of an audio amplifier 78 having as many amplification stages as the purpose of the instrument may require. The output circuit 19 of said amplifier is connected with the voice coil 8| of the loud speaker 80.

The two resistances l5 and 16 have parallel circuits 82, 83 by means of which they may be short circuited. One of these circuits 83 may be permanently closed by means of the contacts 84 of the pedal 85. The second circuit 82 is open at the contacts 81 as long as the loud pedal is not operated.

A sustaining pedal may be used in addition if, for instance, an arrangement similar to that shown in Figure 5 is employed. In this case the sustaining pedal may operate the pedal rod 56.

It will be clear that the oscillations produced by the depression of a key of the instrument will induce currents in coils 22, the voltage of which is stepped up in the transformer while currents are magnified by the amplifier or amplifiers used. These currents act on the loud speaker BB. They have to pass resistance 15 while resistance is normally short circuited. If the forte or loud pedal 86 is operated it closes a short circuit around resistance 15 and no resistance is then included in the input circuit of the audio amplifier 18. The notes produced will, therefore, have maximum volume. If soft pedal 85 is pressed the short circuit to resistance 76 is interrupted and this resistance is now active in series with resistance 15. The volume will, therefore, be out down to a minimum.

The amplifier or amplifiers may be supplied with current from any suitable source of electrical energy, a plug connection 88 being shown for this purpose.

The piano equipped with the tone or note producer units may have approximately the shape of a conventional piano. Figure 11 shows the outline.

The speaker may be arranged in the center of the back wall or in the center of the front wall above or below the key frame, the latter case being shown in the Figure. The audio amplifier i8 is best arranged on one side with its front wall carrying the switch 96 and the main adjustment control 9| projecting outwardly. The adjustment control has only to be operated occasionahy and readjustment is Only necessary at long intervals, or with a change of the use to which the instrument is put. The switch 98 has to be operated before use of the piano. The plug in contacts 93, 94 may be used for earphones or for the connection of the piano with a distant speaker.

It will be clear that the quality of the music instrument may be improved in many ways, if desired. For instance, if it is desired to produce not only the basic musical note but also certain harmonics a plurality of juxtaposed units or of juxtaposed reeds and coils may be substituted for the single unit.

Moreover, it will be clear that the mechanical and electrical details of mechanisms have been specifically described merely in order to be able to illustrate the principles by means of specific examples, but, as it is the principle which constitutes the invention, these specific details may be replaced by others without in any way affecting the invention.

I claim:

1. A device for use in musical instruments for producing musical tones by means of electrical oscillations, comprising a key, a unit for trans lating mechanical oscillations of a frequency corresponding to the frequency of the musical tone to be produced into electrical oscillations, said unit including a frame of magnetized ferro-magnetic material open along one side, a magnet core with a reduced substantially linear and face, a flat strip-like transversely oscillating reed with one freely oscillating and one fixedly supported end of a predetermined free length corresponding to a predetermined natural frequency of transverse oscillations, having a substantially linear end face at its free end, said magnet core and said transversely oscillating reed being longitudinally aligned and being mounted on opposite sides of said frame, projecting towards each other along the open side of the said frame and substantially closing the open side of the frame, with their substantially linear end faces facing each other across a narrow gap, a coil mounted on said ma net core with its longitudinal axis extending along the axis of said core for producing currents induced by the variation of the magnetic fiux through said core, means operated by the key for moving said unit, a fixed member for arresting said movement and for causing an impact producing a vibration of the reed with its natural frequency and an electro-acoustic translation means for translating the electrical oscillations into sound oscillations.

2. A device for use in musical instruments for producing musical tones by means of electrical oscillations, comprising a key, a unit for translating mechanical oscillations of a, frequency corresponding to the frequency of the musical tone to be produced into electrical oscillations, said unit including a frame of magnetized ferro-magnetic material, open along one side, a magnet core with a reduced substantially linear end face, a flat strip-like transversely oscillating reed with one freely oscillating and one fixedly supported end of a predetermined free length corresponding nerd-cs4 to a predetermined natural frequency 'of transverse oscillations, having a substantially linear end face at its free end, said magnet core and said transversely oscillating reed being longitudinally aligned and being mounted on opposite sides of said frame, projecting towards each other along the open side of the said frame and substantially closing the open Side of the frame, with their substantially linear end faces facing each other across a narrow gap, a coil mounted onsaid magnet core with its longitudinal axis extending along the axis of said core for producing currents induced by the variation of the magnetic flux through said core, means operated by said key to impart a rapid motion to said unit, means to arrestsaid motion to cause the reed to oscillate with its natural frequency, and an electro-acoustic translation means for translating the electrical oscillations into sound oscillations.

3. A device for use in electrical musical instrumerits, producing electrical oscillations corresponding to a musical tone comprising a magnetized frame of ferro-inagnetic material open along one side, a magnet core with a reduced substantially linear end face, aflat, strip-like, transversely oscillating reed with a freely oscillating and a fixedly supported end of a predetermined free length corresponding to a predetermined natural frequency of its transverse oscillations, said reed having a substantially linear end face at its free end, said magnet core andsaid transversely oscillating reed being longitudinally aligned and being mounted and projecting from opposite sides of the frame toward each other along the openlside of the saidframe, so as to substantially close said open side, with the substantially linear endfaces of the core and the free end of the reed facing each other across a narrow gap, a coil on said magnet core with its longitudinal axis extending along said core for producing electrical oscillations and mechanical means for producing a vibration of the reed with its natural frequency.

4. A device for use in musical instruments producing musical tones by meansof electrical oscillations comprising a unit for translating mechanical oscillations of a frequency corresponding to the frequency of the musical tone to be produced into electrical oscillations, said unit including a frame of magnetized ferro-magnetic material, open along one side, a magnet core with a reduced substantially linear end face, a flat strip-dike transvcrseiy oscillating reed with a freely oscillating end and a fixedly supportedend of apredeterminedfree length, corresponding to a predetermined natural frequency of its transverse oscillations, having a substantially linear end face at its free end, said magnet core and said transversely oscillating reed being longitudinally aligned and being mounted on opposite sides of said frame, and projecting towards each other along the open side of the said frame, said core and said reed substantially closing the open side of the frame with their substantially linear end faces facing each other across a narrow gap, a coil mounted on said magnet core with its longitudinal axis extending along the said core for producing currents induced by said core, a key, carrying said unit, said unit being fixedly attached to said key, with the reed in substantial parallelism to said key, means for arresting'the movement of said key, to produce an oscillation of the reed by inertia upon arrest of the key and an electro-acoustie translation means for translating the electrical oscillations into sound oscillations.

5. A device for use in musical instruments for producing musical tones by means of electrical oscillations comprising a key, a unit for translating mechanical oscillations of a frequency corresponding to thefrequency of the musical tone to be produced into electrical oscillations, said unit including a frame of magnetized ferro-magnetic material open along one side, a magnet'core with a reduced substantially linear end face, a fiat strip-like transversely oscillating'reed with a freely oscillating nd and a fixedly supported end of a predetermined free length, corresponding to a predetermined natural frequency of its transverse oscillations, having a substantially linear end face at its free end, said magnet core and said transversely oscillating reed being longitudinally aligned and being mounted on opposite sides of said frame, projecting towards-each other along the open side of said. frame and substantially closing said openside, with the substantially linear end face of the core-and the free end of the reed facing each other across a narrow gap, a coil mounted on said magnet core with its longitudinal axis extending along said corefor producing induced currents, a rigid backboard, a support for said unit pivoted to said rigid backboard, a mechanical link connection between said pivoted support and said key, adapted to produce a motion of said pivoted support towards said fixed backboard, cushioning means on the latter arresting the movementof the pivoted support, a further rigid support, forming a rest for the sup port of the unit, damping means applied against the reed in the position of rest, said means being pivotally mounted on said further rigid support, a pedal and means for connecting said pivoted damping means with saidpedal.

6. A musical instrument provided with a number of devices according to claim 1 whereinthe electro-acoustic translation device includes two resistances arranged in series, shunt circuits across each of said resistances, and two pedals, each provided with a contact for controlling one of said shunt circuits.

EVARISTE O. FLEURY.

REFERENCES CITED fhe following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,929,027 Miessner Oct. 3, 1933 1,933,297 Miessner Oct. 31, 1933 2,151,021 Frohman Mar. 21, 1939 2,155,741 Severy "Apr. 25, 1939 2,321,366 Demuth June 8, 1943

Images