US2770994A - Musical instruments with capacitative pickup - Google Patents

Description

Nov. 2,0, 1956 l J. T. KUNZ 2,770,994

MUSICAL INSTRUMENTS WITH CAPACITATIVE PCKUP Filed sept. 21, 1951 IN VEN TOR.

ATTORNEYS United States Patent O MUSICAL INSTRUMENTS WITH CAPACITATIVE PICKUP Jacob T. Kunz, North Hills, Pa., assignor to Schulmerich Electronics, Incorporated, Sellersville, Pa., a corporation of Pennsylvania Application September 21, 1951, Serial No. 247,585 Claims. (Cl. 84-1.14)

This invention relates to musical instruments and particularly to an instrument having a plurality of vibrating elements or rods for producing tones, such as true bell or chime tones and is especially useful in instruments for the production of bell or chime music.

In an instrument of the type involved herein, the vibrations of the rods are picked up electrically and amplified, modified, and then changed into sound by a loudspeaker so as to produce bell music. The amplification is high so that particular care must be taken to remove all undesirable tones and to modify the vibrations to produce the desired partial relationship in each note.

One of the objects of the present invention is to provide an improved bell tone instrument of simplified construction.

Another of the objects of the invention is to provide an improved arrangement for obtaining the proper relationship of partials and strength thereof for all of the rods or vibrators of an electric bell tone instrument.

In one aspect of the invention, the vibrators are of the fixed-free type and are mounted on a supporting block, the block being resiliently suspended from the frame of the instrument. Adjustable mechanical-electrical pick-ups are provided at desired locations relative to the various rods and their support for the purpose of changing mechanical vibrations into electric vibrations. Strikers can be provided for selectively activating the vibrators, the strikers being arranged so that there is a magnetic brake effect which permits the striker to hit the particular vibrator involved with the desired action. Preferably, the rods are provided with an intermittently effective damping arrangement which becomes increasingly effective or accelerates the damping after the vibrator is set into vibration such as described in detail in applicants copending application erial No. 229,380, filed June l, 1951.

In a further aspect of the invention, a circuit arrangement can be used for the purpose of attenuating low frequency vibrations in the rods producing high notes so that the low frequencies in the lower notes will be in a desired strength relative to the high notes.

When the partials of the rods are assembled and are tuned so as to be in the proper relationship, occasionally, it will be found that a particular partial undesirably will cause vibration of the entire block and system. When this occurs, means must be provided to detune the supporting block and system so as to eliminate such undesirable vibrations. In the present invention, this is accomplished by providing means for selectively adding inertia to the system as needed.

These and other objects, advantages and features of the invention will become apparent from the following description and drawings:

Fig. l is a fragmentary side view with portions of the device cut away;

Fig. 2 is a fragmentary top view of the vibrator supporting block of Fig. l;

Fig. 3 is a side View of Fig. 2 with portions broken away and in section;

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2,770,994 Patented Nov. 20, 1956 ICC Fig. 4 is a fragmentary View looking in the direction 4-4 of Fig. 2;

Fig. 5 is a top schematic View of the assembly of Fig. l;

Fig. 6 is a schematic wiring diagram of one form of a circuit which can be used; and

Fig. 7 is a detail enlarged view of one form of plunger.

Referring to Fig. l, supporting block 10 may have xedfree vibrator rods 11 carried in slots 12 (Figs. 1-4), the connection of said fixed-free rods with said block being made such that the rods are acoustically integral therewith. Block 10 can be suspended by means of resilient members 13 from the main frame 14 of the instrument. Resilient members 13 may be fastened to block 10 in any suitable manner, such as by screws 15, the members being connected to the main frame 14 by means of screws 16.

The striker mechanism assembly is carried on plate 18, plate 18 being suitably supported from block 10. In the illustrated form of the invention, resilient C shaped spring members 17 are fastened by screws 19 and 20 to the block 10 and plate 1S respectively so as to resiliently support the striker assembly. A striker is provided for each of the rods, the striker being selectively energized by means of a conventional keyboard switching arrangement which can be operated or played as desired. Preferably, a source of suitable alternating current is utilized for operating the solenoids.

Referring to Fig. 3, for example, upon energization of solenoid 21, the striker plunger 22 will be projected upwardly until it strikes its rod 11 as indicated in the dotdash lines and then Will move away from the rod. The plunger has a portion 21A (Fig. 7) thereof made of a magnetic material, the upper portion 21B being nonmagnetic. The dimensions are chosen so that the plunger upon activation of the solenoid will move up and overshoot suiiicient to strike the rod once and then come to rest Iaway from the rod. A magnetic brake concentrates the magnetic force operating the striker plunger so as to produce the desired striking force and retracted position of the plunger after the rod has been struck and while the solenoid is energized. Upon release of an operated key, the plunger will return to its normal position as illustrated in full lines in Figure 3. Suitable connectors can be provided for connecting the keyboard to the various strikers. As an example of one type of construction, the non-magnetic portion 21B can be in the form of a hollow eyelet with a ared end. The flared end limits the amount that the plunger can move downwardly in the solenoid when the solenoid is deenergized.

Located above each of the rods 11 is an adjustable collector 23. The collector may have a widened face 24 which is adjustably spaced relative to its rod, a slot being provided in one end of the collector for facilitating adjustment by a screwdriver or the like. The collector plate is screw-threadedly mounted in apertures in block 10.

As described in detail in applicants copending application, Serial No. 229,380, ilexible members 25, such as nylon threads, may be loosely mounted in apertures adjacent an end of each of the rods. Flexible members 25 are arranged so that a portion thereof normally rests on a threaded rod 26, threaded rod 26 being fastened to frame 14 by nuts 27. When a vibrator rod is set into vibration, its exible element will jump relative thereto and intermittently come into contact therewith, thus serving to intermittently damp the vibrations of said rod and the flexible element also will jump clear of threaded rod 26. As the amplitude of the vibrator decreases, the flexible element again will come into contact with threaded element 26 and accelerate the damping of the vibration.

Frequently, it is desirable in a musical instrument of the type described employing fixed-free rods, to attenuate the low frequency vibrations in the high notes, such attenuation not being desirable in the lower notes. manner of accomplishing this is illustrated in Figure 6 wherein 28B represents the block on which rods 28, 29, 30 and 31 are mounted. Rods 23 and 29 represent the higher notes, such as those in the range of high G and rods 30 and 31 can be the notes in the range of low For example, high G to Cit below high G can be considered to be higher notes as far as a typical grouping is concerned.

Collector plates 28A and 29A are connected by lead 32 through resistor 33 to the polarizing source of Voltage for the vibrator system. Lead 34 connects grid 35 of the rst amplier tube 36 through a conventional blocking condenser 37. The low note rods 30 and 31 have their collector plates 30A and 31A connected to the polarizing voltage through an additional resistor 38. Thus, the polarizing voltage is furnished for the collector plates of the lower note rods through resistor 33 and resistor 38. In such an instance, the load impedance is lower for the high notes and this will serve to attenuate the lower vibrations therein. The additional resistance in the load circuit for the lower notes makes the load impedance of this circuit such that it does not perceptibly attenuate the lower vibrations therein so that the lower note circuit is substantially less frequency selective than the high note circuit.

In the form shown, the high notes can be connected together by flexible strips 40 (Fig. 2), only the upper one being shown. The lower notes are connected to each other by flexible strip 4l bridging the outer groups of low notes. In addition to the strip 41, strips 42 and 43 are interwoven in the projecting upper ends or shanks of the collectors so as to join them. Resistor 44 corresponds with resistor 38 of Fig. 6.

After the rods 11 and other parts have been assembled relative to base 10, it is necessary to tune the rods so that they produce the correct tone in the loud-speaker LS (Fig. 6) when struck. It sometimes occurs that a particular partial present in one of the vibrating rods will cause undesirable vibration or resonance and interference patterns in the block il@ which will be accentuated in the sound system. In order to provide a way for detuning the system easily in the assembling and tuning operation, the device can be constructed to permit selective addition of weights or mass to the block` One manner of accomplishing this is to provide threaded apertures 45 in the block l0 for selectively receiving weights or plugs. When it is found that an undesirable vibra-tion is present, one or more weights or plugs can be suitably fastened in the various apertures as needed to eliminate the undesirable vibration.

A simplied musical bell tone instrument can be made by following the teachings of the present invention. It is to be understood that details of construction can be changed without departing from the spirit of the invention except as defined in the appended claims.

What is claimed is:

l. In an electric music instrument, the combination including an elongated supporting block having a plurali-ty of fixed-free rods mounted at longitudinally spaced points on said block, a plurality of apertures therein at predetermined locations over the length of the block, striker mechanism for selectively striking said vibrators, electric pick-up means adjacent each of said rods, amplifying means connected to said pick-up means, loudspeaker means connected to said amplifying means, and means selectively placeable in said apertures for detuning undesired resonant vibrations in any part of said block to control tone interference patterns.

2. In an electric music instrument having at least one vibrator, the combination including a solenoid having an aperture therethrough, and a striker plunger for striking said Vibrator, said plunger comprising a separate nonmagnetic material hollow head with a ared top, and a separate magnetic shank fastened thereto, said flared One i head acting as a stop in cooperation with said aperture and solenoid establishing the return position of the plunger in said solenoid when the solenoid is deenergized.

3. In an electric music instrument, the combination including a supporting block, a plurality of vibrators carried by said block, electric pick-up means for each vibrator mounted in said block and having a collecting face in proximity to its vibrator, each of said pick-up means having shanks in spaced relationship to each other and said block, first undulated exible metal strip means interwoven on said Shanks so as to contact diametrically opposed surfaces on adjacently located Shanks, and second undulated exible metal strip means interwoven on said shanks so as to contact diametrically opposed surfaces on adjacently located shanks which are not contacted by said rst metal strip means, said first and second metal strip means serving to electrically interconnect and structurally support said Shanks.

4. In an electric music instrument, the combination comprising a supporting block, a plurality of vibrators carried by said block, said vibrators including a group of vibrators producing high notes made up of a plurality of partials and a group of vibrators producing low notes made up of a plurality of partials, selectively operable actuating means for causing said vibrators to vibrate, an electric pick-up of the variable capacitance type for each vibrator mounted in said block and having a collecting face in proximity to its vibrator, each of said pick-ups having Shanks in spaced relationship to each other and said block, separate collector means for electrically interconnecting the respective pick-ups in each of said groups of vibrators, said collector means comprising undulated flexible metal strip means interwoven on the shanks of the pick-ups in its vibrator group to electrically interconnect them, an amplifier, electro-acoustical means connected t0 the output of said amplifier, means for electrically connecting the collector means of the high note producing group of vibrators with the input of said amplier, and resistor means electrically connecting the collector means of the high note producing group of vibrators with the collector means of the low note producing group of vibrators such that the low frequency partials produced by the high note producing vibrators only are attenuated.

5. In an electric music instrument, the combination comprising a plurality of vibrators each producing a different note made up of a plurality of partials, said plurality of vibrators including a group of vibrators producing high notes and a group of vibrators producing low notes, separate actuating means for each of said vibrators for causing said vibrators to vibrate, an electrical pick-up of the variable capacitance type for each of said vibrators, separate collectormeans for electrically interconnecting the respective pick-ups in each of said groups of vibrators, an amplifier, electro-acoustical means connected t0 the output of said amplifier, means for electrically connecting the collector means of the high note producing group of vibrators with the input of said amplier, first resistor means connected at one end thereof to said lastnamed connecting means, a source of polarizing voltage connected between said vibrators and the other end of said rst resistor means, and second resistor means electrically connecting the collector means of the high note producing groupA of vibrators with the collector means of the low note producing group of vibrators, said rst and second resistor means combining with the capacities of said pick-ups to form frequency selective means for attenuating the low frequency partials produced by the high note producing vibrators.

References Cited in the le of this patent l v UNITED STATES PATENTS 486,013 Wuest, Ir. Nov. 8, 1892 (Other references on following page) UNITED STATES PATENTS Sheldon June 21, 1910 Young May 25, 1915 Bergerson Aug. 22, 1916 Hunt 1an. 14, 1930 Jacobs June 27, 1933 Jacobs Oct. 31, 1933 Severy Nov. 14, 1933 Lesti Jan. 7, 1936 Hosche Apr. 5, 1939 Miessner Aug. 8, 1939 6 Miessner May 14, 1940 Edwards July 2, 1940 Hings Dec. 27, 1949 Fleury June 6, 1950 Merrill, Jr. May 8, 1951 Zuck Oct. 2, 1951 Schmidt Oct. 23, 1951 FOREIGN PATENTS Great Britain May 15, 1947

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