US1979633A - Apparatus for the production of music - Google Patents

Description

Nov. 6, 1934. B. F. MlESSNER 1,979,633

APPARATUS FOR THE PRODUCTION OF MUSIC Filed Oct. 12, 1932 2 Sheets-Sheet l IN VEN TOR.-

A ORNEY.

Mm 5, 19340 B. 1 1,979,633

APPARATUS FOR THE PRODUCTION OF MUSIC Filed Oct. 12, 1932 2 Sheets-Sheet 2 AT RNEX Patented Nov. 6, 1934 rnna'rns FQR THE PRQDUCTIQDN (OF MUSIC Benjamin F. Miessner, Millburn Township, Essex County, N. 5., assignor to Miessner Inventions, Inc, a corporation of New Jersey Application October 12, 1932, Serial No. 637,403

8' Claims.

lhis invention relates to musical instruments of the type wherein the output sound is translated from electric oscillations, and more partlcularly to an improved form and arrangement of the oscillation generator and other apparatus therein.

I have heretofore, in my co-pending application Serial Number 512,399, filed January 30, 1931, now Patent No. 1,929,027 dated October 3, 10 1933, shown such an instrument wherein the oscillation generator comprised a plurality of tuned vibrators with adjacent selective mechanical exciting means therefor. Such an instrument of course permits production of its output sound at a point remote from its vibrators; but because of the adjacency to the vibrators of the exciting means employed, the player must be near the vibrators and a portion of the advantage of sound production at a point remote from the vibrators is thus lost.

According to the present invention the vibrators are excited by means touch-responsively actuatable from a remote point. The advantage is at once secured of ability to produce the output sound near the player, but at the same time to locate the bulk of the instrument at a point remote from him without any undesired loss of his control over its performance.

Accordingly it is an object of my invention to provide an improved musical instrument whereby the output sound may be produced near the player but the vibrators may be located remotely from him. It is a further object to provide improved means for exciting the vibrators in such an instrument. It is a still further object to provide par ticular touch-responsive means for exciting the vibrators from a remote point.

It is an independent but allied object to provide a touch-responsive striking and damping action improved independently of its particular usefulness with any given arrangement of instru ment portions. Other and allied objects will more fully appear from the following description and the appended claims.

in such description reference is had to the accompanying drawings or which:-

Figure l is a partly vertical cross-sectional and partly schematic view of an emboent oi my invention, the upper and lower portions respectively representing portions or the apparatus which may conveniently be located remotely from each other; and.

Figures 2 and 3 are horizontal cross-sectional views of the upper and lower portions of Figure 1, respectively, taken along lines 2--2 and 3-3 oi? that figure, and including a schematic showing of certain parts and electrical connections.

Reference being had to Figures 1 and 3, there will be seen a plurality of strings 1, strung for example from tuning pins (not shown) over edge 2, over bridge 3 and to hitch pins 4. Hitch pins 4 and edge 2 may each be attached to or part or an integrally cast iron frame or plate 39, such as a piano plate. Bridge 3 may be either rigidly or vibratile mounted, according to the desired type of output tone efiects and to principles not involved in the present invention. For exciting the strings there may be provided hammers 5, pivoted to a stationary mounting as at 6 and normally resting against drop-rail '7. For damping each string there may be provided a damper 8, pivoted to a. stationary mounting as at 9, and normally held against the string by a light spring 10.

In Figures 1 and 2 will be seen a plurality of white and black keys 11 and 12 respectively, which may be arranged in the usual key-board formation. At the back of each key may be provided a coil 13 of many turns of fine wire and having a central opening 14. This coil, if wider than the key, may conveniently be supported thereon by a block 15, of the key width or less, thus avoiding any impediment to the motion of one key by the coil attached to another. Above the central opening 14 of each coil and of slightly smaller crosssection than such opening, may be provided a permanent magnet 16, it being understood that upon depression of the front end of any key 11 or 12, the coil 13 thereby carried will be raised to surround the associated magnet 16.

The function of the coils 13 is the development of electric impulses whereby electromagnets actuating the hammers 5 may be energized. Such electromagnets are shown as 18 in the figures, and each will be seen to be wired in series with a corresponding coil 13. Each elect1 magnet 18, upon energization, operates to ac tuate its hammer by attracting armature 1? attached to the hammer shank. Such attraction will be greater, and the acceleration of the hammer hence more rapid, the greater the impulse energizing the electromagnet. The electric impulse, however, is produced by the induction of a voltage in the associated coil 13, such induction occurring upon motion of the coil axially with respect to its permanent magnet 16, and varying with the velocity of such motion. Thus the velocity of the key motion determines the acceleration or" the hammer, and the hammer action system is therefore touch-responsive.

A voltage is induced in each coil 13 not only upon the upward niotioii thereof resulting from depression of the forward end of the key, but also upon the downward motion resulting from key release. Thus unless some step be taken to make ineffective the voltage induced under the latter conditions, the electromagnets 18 would be energized and the hammers 5 actuated upon key release as well as upon key depression. Since the two voltages are of opposite polarity, however, the difiiculty may be avoided by permitting the attraction of each armature 17 by its elec-- tromagnet 18 to occur only upon traversal of the circuit by an impulse in one directioni. e., by impulses of the direction occurring upon key depression. This may be accomplished by polarizing the electromagnets; or, as I prefer, by connecting in series therewith rectifiers 20, for example of the cupric oxide type, appreciably conductive in one direction only.

It will be seen that the striking action herein is affected only by motion of the key, and not by key position, whether up or down. On the other hand conventional .striking actions are affected not only by key motion but also by a stationary, depressed position of the keys. This fact requires the rather complicated system ordinarily provided for tripping the hammer, which system may be dispensed with in the action herein described. This element of my invention is useful regardless of the relative locations of the various portions of the apparatus.

To raise each damper 8 from its string and to hold it raised during the period of depression of the corresponding key, I have shown individual electromagnets 21 each energizable to at-- tract an armature 22 attached to a damper arm 23. The energization of the electromagnets 21 may be efiected by a common battery 24, its circuit being closed through any electromagnet 21 upon closing of the spring switch 25 associated with the corresponding key. Each switch 25 may be arranged to close in the first stage of key depression and to remain closed until the last stage of key release, and preferably comprises a very light spring of negligible resistance to key motion.

It will beunderstood that the dampers 8 might be mechanically associated with the hammers 5 and actuated coincidentally therewith in more or less conventional piano fashion, the switches 25, battery 24 and electimmagnets 21 being eliminated. It is necessary in such case, however, to alter the hammer actuating system so that not only motion of a key 11 or 12, but also its absolute position at any instant, produces an appropriate efiect therein. Not only is this necessity avoided by the use of a separate damper actuating system as shown, but at the same time that portion of the complete system which responds to touch-4. e., the key-is freed of the mechanical resistance of the damper. This not only reduces the demands made upon the touchresponsive impulse generators, but also tends to heighten the degree of possible control efiected by touch.

To raise all the dampers 8 from the strings at once, I have shown a bar 26 passing behind allthe damper rods, and supported for example by a plurality of mounting arms 27 pivotally secured as at 28 to a rigid mounting. A spring 29 attached to eachmounting arm may lightly urge the bar 26 against the damper rods. Attached to the bar 26 may be a plurality of armatures 30, attractable by commonly excited electromagnets 31 to move bar 26 and thus to raise ovaeae all the dampers. These electromagnets 31 may be excited as by battery 32, upon closing of spring switch 33 by depression of pedal 34:.

Illustrative apparatus for translating the vibrations of the strings 1 into electric oscilla tions and thence into sound has been shown schematically in Figure 1 and may be described as follows:

Opposite, and forming a minute electrical capacity with, vibratory portions of all the strings 1 may be provided a conductive strip 41, secured for example to stationary insulating mounting strip 42. Conductive strip 41 may be connected to the grid of a thermionic vacuum tube 43, whose cathode may be energized in any suitable manner, whose anode current may be supplied as from a tap on battery or other source 44, and whose grid may be biased through a high resistance 45 to a point rendered slightly more negative than the cathode by virtue of anode current flow through condensively by-passed resistance 61. In the output circuit of tube 43 may be connected amplifier 46; and the output of this amplifier may be led to volume control or potentiometer 47, operated as by pedal 48, and thence to loudspeaker or otherelectro-acoustic translating device l9. Because of the sensitivity of portions of the translating apparatus to stray electrostatic fields it is desirable to provide electrostatic shielding therearound, as indicated schematically by shielding 62 in Figure 1. This may be electrically connected to plate 39.

The strings 1 may be rendered at a D. C. potential different from that of the conductive strip 41 by virtue of connection of the plate 39, with which the strings make contact, to the positive terminal of battery or source 44. Thus the total capacity formed by the paralled minute capacities between the several strings and strip 41 is charged to the potential of battery 44 through resistance 45. Because of the high value of this resistance, this charge cannot change rapidly. Hence oscillatory variations in the capacity, produced by vibration of the strings, will produce corresponding oscillatory variations in the voltage across the capacity, and therefore across resistance 45. This voltage is applied to the grid of tube 43 and, amplified by that tube and by amplifier &6, appears across potentiometer 47, from which any desired fraction may be supplied to loudspeaker 19.

It will be understood that the mechanico-electro-acoustic translating apparatus above described is illustrative only and may be varied and/or elaborated upon without departing from the spirit of this invention.

It will now be seen that with the apparatus divided as illustrated, the two portions may be located at any desired distance from each other;

no connections other than electrical are required between them; the output sound may be produced as near the player as desired; and no loss of control, even in respect of touch-response, is experienced as a result of the division. It will also be appreciated that other forms of electric impulse generators than the magnet and coil combination 16-18 may be employed, such as coils cutting a magnetic field maintained at right angles to their turns, etc. It will finally be understood that in its broadest aspect my invention may make use not only electrical but of pneumatic, mechanical or other means for touch-responsively connecting the hammers with the keys over an appreciable distance.

I claim:'

1. In a musical instrument of the type wherein a plurality of tuned vibrators are selectively excited by selective electric actuation of electromagnetically operative exciting devices respectively associated therewith: means for selectively actuating said devices, comprising a plurality of keys each movable at various velocities and a plurality of magneto-electric generators, each mechanically associated with one of said keys, electrically connected with one of said exciting devices, and arranged to generate upon key depression an electric impulse of amplitude directly responsive to the velocity of such key depression.

2. In a musical instrument of the type wherein a plurality of tuned vibrators are selectively excited by selective electric actuation of electromagnetically operative exciting devices respectively associated therewith? means for selectively actuating said devices, comprising a plurality of keys each movable at various velocities; a plurality of magneto-electric generators, each mechanically associated with one of said keys, electrically connected with one of said exciting devices, and arranged to generate upon key motion an electric impulse of amplitude directly responsive to the velocity of such motion; and means associated with said generators for suppressing such impulses of one polarity.

3. In combination in a musical instrument, a tuned vibrator; electrically actuable means associated therewith for exciting the same; a key movable at velocities; and means electrically connected with said exciting means and mechanically associated with said key for supplying to said exciting means upon depression of said key an electric impulse of amplitude directly responsive to the velocity of such key depression.

4. In combination in a musical instrument, a tuned vibrator; electromagnetically operable means associated therewith for exciting the same; a key movable at various velocities; and a magneto-electric generator electrically connected with said exciting means, mechanically associated with said key, and arranged to generate upon depression of said key an electric impulse, of amplitude directly responsive to the velocity of such key depression.

5. In combination a musical instrument, a tuned electromagnetically operable means associated therewith for exciting the same; a key movable at various velocities, a magneto-electric generator electrically connected with said exciting means, mechanically associated with said key, and arranged to generate upon motion of said key an electric impulse of amplitude directly responsive to the velocity of such motion; and a rectifier electrically in series with said generator, whereby to isolate said exciting means from such impulses of one polarity.

6. In a musical instrument of the type wherein a plurality of tuned vibrators are selectively excited by the selective electric actuation of exciting devices respectively associated therewith: means for selectively actuating said devices, comprising a plurality of keys each movable at various velocities and a plurality of means, each mechanically associated with one of said keys and electrically connected with one of said exciting devices, for supplying to such exciting means upon depression of such key an electric impulse of amplitude directly responsive to the velocity of such key depression.

7. In a musical instrument, the combination of a tuned vibrator; a hammer adapted to strike said vibrator; an electromagnet adapted upon energization to move-said hammer to strike said vibrator; a key movable at various velocities; and a magneto-electric generator, mechanically connected to said key, and electrically connected to said electromagnet to energize the same in accordance with key velocity.

8. In a musical instrument, the combination of a tuned vibrator; a hammer adapted to strike said vibrator; a polarized electromagnet adapted upon energization to move said hammer to strike said vibrator; a key movable at various velocities; and a magneto-electric generator, mechanically connected to said key, and electrically connected to said electromagnet to energize the same in accordance with key velocity.

BENJAMIN F. MIESSNER.

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