CA1080008A - Method of and apparatus for producing musical instrument keyboard-controlled pitch variation tone alteration and the like - Google Patents

Abstract

This disclosure is concerned with stringed or similar instruments having keyboards in which variations in pitch and tone are effected by enabling longitudinal backward and forward movement of the keys in addition to their tone-producing depressing operation, with, for example, the tensioning of the strings themselves being altered in response to the longitudinal backward and forward movement of the corresponding key; or, in the case of electronic instruments, causing transducers or similar devices to be acted upon by the longitudinal movement to effect electronic variation in note production in response thereto.

Description

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The present invention relates to methods o~ and apparatus for producing pitch variation, tone alteration and related effects in musical instruments and the like, being more particularly directed to a keyboard instrument wherein sound, produced by depression Or an individual . .
longitudinally extending key o~ the keyboard, may be ~
modi~ied by movement longitudinally backward and forward -in the plane of the key, resultlng in the sustained ~ ;
varlation of pitch ("bent" notes, ~ustly intoned ln-tervals, glissando, sliding pitches, etc.,) and other varying characteristics.
The present state o~ the art in keyboard musloal lnstruments ranges ~rom those instruments in which a oonstant pitch is created by each individual key, to those instruments in which a vibrato effect may be created by a horizontal oscillation of blocks o~ keys, ;
as disclosed, ~or example, in U. S. Letters Patent Nos. 1,853,630 and 1,914,831. Additionally, monophonic . .
lnstruments have been proposed in which a glissando effect may be created between pitch steps, as described ln U. S. Letters Patent No. 2,871,745, and insbruments in which control o~ the pitch i8 ef~ected a~ter the initlal tone is struck by means of a double touoh control _ system, as described in U. S. Letters Patent No. 3,652,774, : - . . .

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and in whlch application of an additional secondary amount Or rorce upon the key after the original tone ls struck allows another means o~ control o~ the tone;
the stronger the additional secondary force, the more the variations of the pitch. Still other approaches have involved instruments in which do~nward depression o~ the key produces an expression control (i.e., volume control or, vibrato ef~ect) by a lateral shaking of the keys, as illustrated in U. S. Letters Patent No.
3,715,447. Tension o~ the sound-creating string can also be varied by means o~ foot pedals, as in U. S.
Letters Patent No. 3,763,735. Such prior proposals have not, however, provided simple and ready indiv-idual control Or each key-produoed tone, or the de-gree o~ rlexibility resulting from such a ~eature.
It is aocordingly an obJeot o~ this invention to provide a new and improved method o~ and apparatus for producing musical instrument keyboard-control pitch variatlon and tone alteration and the like that is not subJect to such limitations, but ena~les faciie individual key control.
A further ob~ect is to provide a novel stringed or similar muslcal instrument having a keyboard that allows indlvidual oontrol o~ each key to make possible variations in pitch, tone alteration and other related e~feats, such as "bent" notes, Justly intoned intervals, sliding pitches, gllssando, etc., in direct response to the backward and forward ~longitudinal motion of each longltudlnally extending key. Such backward and ~or- -~
ward motlon has dlstlnct advantages over the lateral .

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horizontal motion of the prior art, above-discussed, since such motion is readily consistent with the simple bone and : ;
muscular action of the human hand, is in the plane of motion of the finger depressing the key, and since it enables every key to be free to move independently~ Another distinct advantage -of the backward and forward longitudinal motion of the key mechanism, directly related to the pitch variation, is that each individual key mechanism may slide the pitch intonation higher or lower responding to the backward or forward motion of the key. The ability to change the pitch in either a higher .
or lower direction is distinctly advantageous over the prior proposals such as double touch key mechanisms, before discussed, partlcularly since they allow movement only in one direction rom the original pitch stxuck, In summary, rom one o its broader aspects, khe invention embraces a method of introducing tone variations to the sound created by downwardly depressed key mechanisms in musical instruments and thie like, that comprises, mounting each longitudinally extending key mechanism with individual :.
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freedom of longitudinal motion in the direction backward and forward in the plane of the key; limitlng the backward and orward movements within predetermined limits; and responding .
to said backward and forward movements of the downwardly : depressed key mechanisms, to introduce corresponding pitch ~ . .
variations, tone alterations and related effects,;separately ~ .
and differently generated for each such indi~idual key :
mechanism in accordance with the :...... .. .
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degree of backward and forward movement of the same.
The a~ove method may be carried out in a musical instrument having planar longitudinally extending keys ~or manual depression to produce sounds, key centering and positioning means connected with each key adapted to enable downward depression and independent movement of the same longitudinally backward and forward substantially in-the plane of the keys, the means being provided with limiting means for restricting such backward and forward movement within predetermined limits, and means connected with and responsive to the-movement of the positioning means for introducing controlled pitch variation, tone alterations and related effects in response to the backward and forward movement of the individual key, independently altering the sound developed by depression of each key.
Other and further eatures will be explalned herein- ~ !
atcr and are more partlcularly dslineated in the appended claims.
The invention will now be described with reference to the accompanying drawings in which:
Fig. 1 is a perspective view, partly in section, of a key mechanism of a stringed musical instrument constructed in ;' accordance with the invention;
Fig. 2A is a similar view of a portion o Fig. 1, upon an enlarged scale, illustrating the key-centerlng-and-posi~ioning mechanism;
Fig. 2B is also a perspective view illustrating means , for avoiding con~flict between ad~acent keys in backward and i~- forward motion;
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Fig. 2C is an exploded plan view of a strlng tensioning , device;
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8000~3 Fig. 3 is a view similar to Fig. 1 of a modified key mechanism of a stringed musical keyboard instrument embodying the invention-, Fig. 4 is a side elevation, partly sectionaliæed, of an embodiment applied to an electronic key mechanism;
Figs. 5 and 6 (appearing on the same sheet as Fig. 3) are graphs illustrating relationships between distanc:e of key ;
motion and pitch variation and relationships between distance of key motion and force applied to the key, according, to the present invention.
In the embodiment of Fig. 1, the frame 1 oi the - 4a -dap/\~"'~J

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key mechanism of a stringed musical instrument is shown supporting one of an intended plurality of planar longitudinally extending keys 2 that, upon manual downward depression produce sounds by striking strings 19, as is well known. The playing surface of the said keys 2 is preferably provided with lateral ridges 3, or surface undulations or other roughening or friction means such as fiber coverings or the like, for enabling non-slipping backward and forward longitudinal movement of the key, substantially in its plane, and while at the same time allowing untroublesome lateral motion of the player's fingers across the surface of the keys. The keys 2 may be arranged in two groups; the playing surfaces of the first group 2a, Fig. 2B, extending farther out to the outer edge of the instrument and being interiorly recessed or narrowed where passing under the playing surfaces o the keys of the ~!!~ . .
other group 2b. The overhanging interior key~ of the other group 2b allow motion relative to that of the keys of the first group 2a and in a plane parallel to the playing surfaces of both groups, but without keys of the two groups coming into contact, and without producing gaps in the playing transverse overall key- `
board surface that would hinder the player~
Referring now particularly in ~igs. 1 and 2A
each key 2 is shown forwardly guided by a pin 4, which makes sliding contact with the inside of a slot 5, the `~
long axis of which is paralleL to the longitudinal axis of the key. A bearing 6 is affixed to the top of the~

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~-: 108~08 ' '' .'' key 2 at its intermediate pivot region and is provided on its lower side with a cylindrical bearing surface 7 apertured to receive the upper end of a vertic~l pin 8 that is accomodated in a longitudinal notch 9 in the key 2~ The - ~:
elongation of the slot 9 parallel to the longitudinal axis of the key 2 permits some rotation o~ the pin 8 a~out the axi.s of cylinder 7, and the pin 8 also pxeYent axial Xotation and lateral translation of the key 2. At its lo~er endt the pin 8 is affixed to a bearing surface lO xesting on rails 11 .
extending transversely to the keys 2 and under the same. A
plate 12 is disposed between the underside of the key 2 and the rails 11 and is longitudinally slotted to accomodate the : , lower part of th.e pin 8~ with a spring 13 di.spo,s,.ed between the ..
plate 12 and the bearin~ surface 10. Dis.c 14 ~ixed to the ~; bearing surfacq 10 ~nd notch 15 in the 'unde~side o~ plate 12' .'~
maintain alignment of the spring 13. The latexal motion of the bearing surface 10 along the rails. 11 is pre~ented ~y the .. , adjacent bearing surfaces lQ of the adjacent ke~ ~echanisms :.
(not shown) and ~X blocks at either end of the xails 11, '.: '.
~2Q Upon the application of a foxce having a component ' :~
`in the longitudinal direction of the key 2~ the pin 8 rotates .:.
either backward or forward, depending upon the resulting sliding motion o~ the key, backward or forward~ xocking about ' .
either the rear or forwaxd rail 11 ~nd allowing the key 2 to .~ .
move longitudinally under the control of the foxward pin 4 in its slot 5 and the pivot pin 8 in its slot 9. T~e ~ey :~.
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thus can be ~ .

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moved from its center, zero or rest position, longitudinally backward and forward substantially in its plane. The bearing surface 10 presents a controlled opposing force to such motion, and the predetermined limits to the backward and forward motion are determined by the pin 4 in its forward slot 5. An adjustment may be provided for the pin 4, allowing variations in the predetermined limits of motion.
A rubber or similar pad 16 is shown affixed to the upper rear por-tion of the key 2 7 Fig. 1. Upon depression of the key 2, the pad 1~ establishes contact with a tensioner ~
lever 201 which is driven upward until it contacts a i horizontal rail 18 covered by acoustic and impact deadening material and affixed at its ends to the rame 1. The tone-producing string 19 is intermediately looped around two pulley segments 20 mounted near the top of the tension~r lever 201, being clamped between them in su~h a way that backward and forward motion of the lower end of said tensioner lever 201, as the key 2 is moved longitudinally ~ackward or forward by the finger, decreases and increases the tension o~
the string 19. A rotational force on the tensioner lever 201, generated by the difference in points of origin on the ~ensioner lever o the orce vectors produced by the tension on the segments of the string 19 ahead of and behind the lever, is counterbalanced by a tension spring 21 affixed to the lower end of the tensioner lever 201 with rotational freedom in a :
plane parallel to the longitudinal axis of said key 2. The . .

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- 108VI~)08 tension spring 21 is affixed at its forward end to an `
adjustment collar 22 threaded on an adjustable bolt 23 attached to a wrest plank assembly 24, fixed to the frame 1 at its ends. At its forward end, the spring 19 is fixed to a wrest pin 25 over a transverse nut bar 26 and under a bar 27 which is adjustable in height.
When the tensioner lever 201 is driven upward by the depressing of the key 2, the string 19 contacts a bridge 28 shortly before it comes to rest against the rail 18. The :
portion of the string 19 between the bridge 28 and the rear hitch pin 29, affixed to the frame 1, then is set into vibration by its sudden deceleration at the bridge 28.
When the key 2 is thus moved longitudi.nally backwards and orwards subsequent to depression, the tensioner ~'' ., lever 201 accordingly varies tension of the string 19, changing its musical pitch. Spring clip 32, as more particularly shown in Fig. 2C, is affixed to said string 19 by keeper 33, allowing the changlng of length of the string 19 as required to effect a given tension change. When the key 2 is released, the tensioner lever 201 drops tension of the string 19, returning the same to its equilibrium value and damping oscillation by damping strip 34, Fig. 1.
Fig. 5 illustrates by way of example several relationships between distance the key moves longitudinally and the restoring force that opposes such motion. In graph (mj a linear relationship between restorlng force away from :, and toward the player is~shown as a functlon of longitudinal displacement D. Other relation-:.,' ~ .
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ships may, of course, be introduced to produce desired tone "bending" information, sliding pitch, glissando and similar e~fects, by appropriate adjustment and shaping of the mechanism. As another example, graph (n) o~ Fig. ~ shows a nonlinear relationship in which the rate of increase of the restoring force is adjusted such that the rate of increase of the restoring force over a predetermined limited distance of motion is greatest immediately above and below the zero position, with the rate of increase of the magnitude of the force being more gradual on either side thereof. In the modified nonlinear relationship of graph ~nl) of Fig. 5, the rate of increase of the restoring force has three steep transitions, two on each side of the zero position, with gradual intermediate restoring force - displacement slopes.
Fig. 6 ~hows by way o ~imilar example several relationships between distance D through which the key moves longitudinally, and the corresponding change in the musical pitch or other controlled variable. In graph (j), the pitch or similar controlled variable changes linearly with the longitudinal motion of the key; whereas in graph tl), the pitch c~langes non-linearly with its variation per unit of longitudinal motion D of the key being slightest immediately adjacent to the re~t position of the key. In graph (11), on the other hand, similar regions of minimal change occur symmetrically on each side of the zero or rest position.
Clearly, other variations will readily suggest themselves to those skilled in the art.

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such as string 19, are shown mounted between pins 25 . .
and 29 and associated elements 26, 27, etc. with the tensioner lever 201 and tensioning-changing mechanisms disposed above the keys 2, in the modification of Fig. :

3, the keys 2 with their longitudinal sliding controls

4~5, 7-8, etc. are illustrated as disposed below the keys 2. In both embodiments, moreover, the strings -~
may either be audibly monitored with an appropriate sounding board, and/or electronically reproduced as by a transducer 30 mounted by electrically insulated pads 31 to generate an electrical signal in response to the proximal vibrations of the respective strings 9.
Still a further modif-led system particularly `
adapted for electronic tone production is shown in Fig. 4, where the keys 2 are shown at the top, pro-vided with their forward longitudinal guiding pin and slot structure 4-5, but rearwardly pivotable at 35. ~one-generating oscillators and the like are not shown, the figure illustrating only the portions for sensing the depressing of the key to activate the tone generator and the sensing of the longitudinal movement for variation.
~ C-shaped flat spring 36 i5 interposed be-tween the frame 1 and the key 2, providing upward re-storlng force to the key while allowing the key to travel freely longitudinally in a backward and forward direction, with further springs 37 and 38, interposed between the pivot ~oint 35 and the frame 1, and be-"`-' ~i~ . ' .

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1~8~00~3 tween the underside of the key 2 and a lower plate extending from the lower arm of the spring 36, res-pectlvely.
When the key 2 is depressed, spring 38 es-tablishes contact with resilient keying contacts 39 and with a pressure-sensitive resistive block 40, as of carbon or piezoelectric or similar material. As the key is moved backwards and forwards longitudinally, subsequent to being depressed, the springs 36, 37 and 38 accomodate this motion, and pick-up pressure- `
sensitive resistive elements 41, dlsposed on each side o~ grounded sprin~ 37, differentially monitor the rocking motion of the spring 37. When the key 2 is re-leased its upward motion is limited by a clip 42 en-gaging a frame proJection 43 forward of the front end o~ the key. Clearly, other types of sensing elements may also be used, as i8 well known.
Further modifications will also occur to those skilled in the art, and such are considered to fall within the spirit and scope of the invention as de-fined ln the appended claims.
What is claimed is: ~

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Claims (9)

1. A method of introducing tone variations into the sound created by the impact of downwardly de-pressed longitudinally extending planar playing key mechanisms in musical instruments, that com-prises, depressing the key mechanisms individu-ally; moving each key mechanism with individual freedom of longitudinal movement backward and forward substantially in the plane of the keys;
limiting such backward and forward movement with-in predetermined limits; and responding to said backward and forward movement of the downwardly depressed key mechanisms to introduce correspond-ing pitch variations, tone alterations and related effects, said pitch variations being separately and differently generated for the individual key mechanisms in accordance with the degree of back-ward and forward movement of the corresponding key mechanisms.

2. A musical instrument having planar longitudinally extending keys for manual depression to produce sounds, key centering and positioning means con-nected with each key adapted to enable downward depression and independent movement of the same longitudinally backward and forward substantially in the plane of the keys, said means being pro-vided with limiting means for restricting such backward and forward movement within predetermined limits, and means connected with and responsive to the movement of said positioning means for introducing controlled pitch variation, tone alterations and related effects in response to said backward and forward movement of the individual key, independently altering the sound developed by depression of each key.

3. A musical instrument as claimed in claim 2 in which said instrument is stringed, said means to enable downward depression effects sound-ing of a string, and said pitch variation introducing means comprises means for varying string tension.

4. A musical instrument as claimed in claim 2 and in which said instrument is electronic, said means to enable downward depression effects electronic note production, and said pitch variation introducing means comprises trans-ducer means coupled to said key mechanisms and responsive to variation in longitudinal position thereof.

5. A musical instrument as claimed in claim 2, where-in said centering and positioning means is pro-vided with an element generating a restoring force upon each individual key to return said key to predetermined limits of motion and pos-itions intermediate the same.

6. A musical instrument as claimed in claim 5 wherein said element is provided with a nonlinear restor-ing force.

7. A musical instrument as claimed in claim 6 wherein said restoring force is adjusted such that the rate of increase of the restoring force is greatest immediate the position at which said force is zero.

8. A musical instrument as claimed in claim 2 wherein the keys are provided with means for limiting troublesome sideways motion of the same.

9. A musical instrument as claimed in claim 2 wherein said keys are of two groups, the playing surfaces of one group extending beyond those of the other group with the playing surfaces of said other group overhanging the playing surfaces of one group, each key of both groups being independently movable longitudinally in its plane.