US2658420A - Sound chamber for accordion pickup - Google Patents

Description

Nov. 10,1953 w w, POM 2,658,420

SOUND CHAMBER FOR ACCORDION PICKUP Filed April 18. 1950 0 eg 8 2 5 1 O 020 8 0 0 1 O 2 3 Fm. O 0 0 O 020 b P 3 r o 5 ATTORNEY.

Patented Nov. 10, 1953 UNITED STATES PATENT OFFICE SOUND CHAMBER FOR ACCORDION PICKUP Wilson W. Pompili, Cleveland, Ohio Application April 18, 1950, Serial No. 156,635

5 Claims.

1 This invention relates generally to accordions and more particularly to accordions which are wired for sound amplification.

For purposes of this description, accordions can be classified into two general groups. One group consists of small accordions such as are used by beginners or students. These instruments have a treble section and a bass section each of which may consist of two or more banks of reeds. When any particular key on this instrument is depressed, it effects the opening of a predetermined number of air ports which are associated with certain reeds in the reed banks, thus resulting in the production of a musical note or chord. No provision is made in these instruments for varying the sound produced by any particular key. The key uniformly produces the same musical sound or note each time it is depressed. This is a rather simple type of accordion and it is mentioned herein only to distinguish it from the professional accordions which form the second group.

The accordions of the second group are the kind generally used by advanced players and professional entertainers. These accordions have a greater range than those of the first group and usually have four or more banks of reeds in the treble and bass sections. In addition, these accordions have shifts or shift keys of which there may be any number such as five, eight, ten, thirteen, etc. The function of a shift key is to cause the temporary closing or blocking of the air ports under a certain bank of reeds or combinations of banks of reeds so as to prevent the passage of air through these reeds even when the appropriate treble key is depressed. Thus by eliminating certain high treble or low treble banks of reeds different harmonics and effects are obtained which may simulate the sounds produced by other instruments, such as clarinet, violin, full orchestra, etc.

My invention pertains primarily to this latter group of accordions and is intended to overcome some of the difliculties which have been encountered in obtaining satisfactory musical performance from these instruments.

There are two especially bothersome problems which are encountered by the professional player. Firstly, is the problem of choking, which occurs in accordions when too great a volume of air is forced through the reeds. This problem. is chronic in the shift type of accordion. Thus, when a player shifts from orchestra to violin the number of outlets or ports in the treble section through which air can pass is greatly diminished. The full power and pressure of the bellows is thereby acting upon only a very few reeds and causes these reeds or some of them, to lock or freeze or choke up, so that they do not vibrate and therefore produce no sound. Theoretically, the player should be able to so control the pressure on the bellows that such choking will be avoided. However, in practice it is almost impossible to sense accurately just how much pressure the reeds will take, and furthermore, it is difficult to abruptly change the timing and pumping technique to which one is accustomed. Therefore, in practice, choking almost always occurs under the conditions mentioned, even though the player he an expert.

Secondly, in using an electrical microphone or pick-up for amplification of sound through a loud-speaker, which many players use whenv giving public performances, the player usually finds that the microphone is very sensitive to the reeds which are in close proximity to it, but is less eifective in sensing the reeds which are located an octave or so away from its vicinity. The tones of the near reeds therefore drown out the tones of the far reeds and objectionably dominate the melody being played. The pick-up is usually mounted on one of the banks of reeds in the treble chamber or on the wall of the chamber itself and thus its physical location naturally induces it to be more sensitive to some notes than to others.

It is a primary object of my invention to provide control means for overcoming the difficulties in accordion playing heretofore mentioned.

Another object of my invention is to provide means for focusing or directing the sounds into the microphone so that it will sense equally both the reeds close to it and those which are remote from it.

Still another object of my invention is to provide air flow control means which may be adjusted to correlate the flow of air through the reeds with any increase or decrease in the number of available air openings, thus preventing choking of the reeds.

A further object of my invention is to provide means for quickly and easily adjusting the aforementioned air flow control means.

Another object of my invention is to provide means of the character described which are so designed as to be attachable to existent accordions.

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

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

Fig. 1 is a front elevation of an accordion embodying the features of my invention, portions thereof being broken away to show certain details.

Fig. 2 is a vertical cross-sectional view taken on line 2-2 of Fig. 1.

Fig. 3 is a cross-sectional View showing the control knob taken on line 33 of Fig. 2.

Fig. 4 is a fragmentary cross-sectional view taken as indicated by line 4-4 of Fig. 2.

Referring more particularly to the drawings, I have shown, in Fig. l, a conventional accordion which comprises a bass reed chamber I, a treble reed chamber 2, and a flexible bellows 3 secured between the chambers and 2. A keyboard I and keys 5 for the bass section are provided adjacent the chamber I, and a keyboard 6 and keys I are provided adjacent the treble section 2.

Each end of the bellows 3 is provided with a rigid frame 8, which is customarily made of wood, and the frames 8 nest into the bass and treble chambers I and 2, respectively, and are secured to the chambers by means of pins 9. In many types of accordions, the frame 8 is recessed to provide a shoulder or ledge ID, and, as will more fully appear hereinafter, I may utilize this ledge in assembling my novel sound chamber or reflector to the accordion.

Each of the chambers and 2 has secured therein a plurality of banks of reeds, one of these banksin the treble section being shown and designated by reference numeral II. The accordion also is provided with a plurality of shift keys I2 which function to close certain selected alr ports in the treble section so as toobtain desired musical effects as heretofore mentioned.

It will be understood that the structure and ar rangement of the reed banks II and shift keys I2 as well as the other well known components of the accordion are in accordance with the teachings of'the prior art and form no part of the present invention.

As is customary in accordions used by professionals, the accordion is equipped with a small microphone or pick-up I3 which, for purposes of utilizing my invention, is secured to one of the reed banks II in a central location in the treble chamber 2. As previously stated, the pick-up will have a tendency to be more sensitive to the vibrations of the reeds closest to it than it will be to more remote reeds such as those which are located close to the periphery of the chamber 2. In order to overcome this objectionable localizing of the sensitivity of the pick-up I3, I have provided a sound collecting and reflecting panel I4 which is interposed between the bellows 3 and the treble chamber 2. If the frame 8 of the bellows is not provided with a recessed shoulder I0, the panel can be secured to the frame in overlying relationship thereto. However, if the frame 8 has a shoulder or ledge I0, then the panel I4 can be nested within the frame 8 in abutmentwith the ledge I0 and may be secured thereto by suitable fastening means I5. The panel I4 may be made of any suitable material such as wood, plastic, or pressed-board. The panel may also be covered or coated with a sound-absorbent material such as felt, if the player desires a soft tone such as is customary in radio work. An uncoated wood or plastic panel gives a sharper more ac centuated tone and is more suitable for dance work and polka music.

The panel I4 has an arcuate or dished center portion which forms an acoustic shell I6. The panel is so disposed that the concave side of the shell I6 faces the treble reed banks II, and the center of the shell is directly opposite the pick-up l3. The curvature of the shell is such that the sounds produced by the vibrating treble reeds will be collected in the shell I6 and will be reflected and directed toward a focal point, which is substantially coincident to the location of the pick-up I3. Thereby the vibrations of those reeds which are remote from the pick-up I3 are amplifled substantially equally as well as the near reeds and the melody played is not dominated by the notes of the near reeds.

The reeds of the bass section I are more resonant and give a fuller and louder tone than the reeds of the treble section 2, so that it is usually unnecessary to amplify the bass section to any great extent. However, in order that some amplification of the bass section shall occur and that it be not completely isolated from the pickup I3, a plurality of openings or slots I? are pro-. vided in the shell I3, which permit the sounds of the basssection to be sensed by the pick-up and amplified, although not to as greata degree as the treble section is amplified.

The openings I! also serve to permit air to pass through the panel I4 from the bellows 3 so that the treble section 2 can be actuated. As will more fully appear hereinafter, the openings [l are de. terminative of the minimum amount of air which can pass through the panel I4. The amount of air permitted to pass by the openings I! is gen: erally inadequate for proper playing of the accordion, although under certain conditions of shift, when a very large number of the treble reed air ports are sealed, this minimum air flow is adequate and desirable to prevent choking.

Means are provided to increase and control the flow of. air through the panel I4, and for this purpose a series of spaced openings iii are pro.-vv vided in the panel I4 adjacent to andparallel with one edge thereof. A valve element. l9 in the form of a perforated slide bar overlies the openings I 8, and is slidablymovable in spaced guide channels 20 which are secured to the panel I 4. The slide bar I9 is provided with a series of openings, 2| which correspond in size and spacing to the openings I 3. In the embodiment of my invention shown in the drawings, the space between adjacent openings I8 or 2| is equal to the width of the opening I8. However, it is to be understood that the openings I8 and 2| may be of such size and may be so spaced as is desired and that my invention is not restricted to any particular size or spacing of said openings.

The slide bar I9 terminates at one end thereof in a rod-like extension 22 which projects through the upper wall 23 of the treble chamber 2 to the exterior ofv the accordion. The extension 22 is slidably mounted in a sleevebearing 24 which is disposed in the wall 23 and which serves to guide the extension 22 in its longitudinal movements.

An expansion coil spring 25 has one end thereof secured to the slide bar I 9 near the extension 22, and the other end thereof is anchored in the panel IA. The spring 25 is maintained under tension so that it urges the slide bar to move longitudinally upwardly toward the wall 23.

The upward movement of the slide bar is arrested and controlled by a knob 26 which is rotatably mounted on a stub shaft 21 which is supported by a base plate 28 secured to the wall 23 f the accordion. The undersurface of the knob 26 is a face cam 29 having its lowest point at 30. The cam surface 29 increases in height gradually and continuously from the point 30 to a high point 3| which is almost 360 removed from the point The difierence in level or height between the points 30 and 3| is equal to the width or" an opening 18 or the space between these,

openings.

The knob 26 is so located relatively to the extension 22 that the free end of the rod 22, which is preferably slightly rounded, abuts the face cam 29. The undersurface of the knob is provided with a series of circumferentially spaced arcuate depressions or recesses 32 which are adapted to engage the end of rod 22 as the knob 26 is rotated, thereby serving as detents which retain the knob in any of several selected positions of angularity.

When the knob is rotated to the position shown in Figs. 2 and 3 of the drawings, the camming surface 29 causes the extension and slide bar to move downwardly against the action of the spring 25. When the end of the rod 22 abuts the point 30 on the cam, the slide bar openings 2| lie intermediate the panel openings 18 and the openings I8 are thereby sealed against the passage of air. In this position of the slide bar, air passes through the panel l4 only through the openings 11, and thus, as previously stated, provides a minimum of air flow to the treble section.

Rotation of the knob to the left or clock-wise, as Viewed in Fig. 2, permits the slide bar to move upwardly gradually, thus exposing progressively increasing portions of the openings Hi. When the rod 22 abuts the point 3| of the cam 29, the slide bar 19 is in its uppermost position and the openings IS in the panel M are fully exposed. This position of the slide bar permits the maximum of air fiow through the panel. Intermediate conditions of air flow can be obtained between the points 30 and 31 of the cam 29.

Inasmuch as each separate manipulation of a shift key 12 may require a different degree of air flow in order to forestall choking, the knob 23 may have to be rotated to a difierent position each time a shift is changed. As many recesses 32 as are desired can be provided on the knob 20 so that rapid and accurate adjustment of the valve member 19 can be obtained.

Suitable indicia may be provided on the knob to assist the player in manipulating it to a selected position.

Thus it will be seen that I have provided an adjustable valve member which controls the flow of air from the bellows to the treble section and thereby avoids choking of the reeds resulting from an over-abundance of air flow. I have also provided an acoustic shell which serves to direct the treble notes toward a central point of pick-up, thereby avoiding over-amplification of the reed vibrations which are close to the microphone.

Having thus described my invention, I claim:

1. A device for use in an accordion, comprising the combination of a panel interposed between the treble section and the bellows of said accordion, a concave arcuate acoustic shell provided on said panel, said panel having air openings therein, a valve member slidably secured to said panel in operative relationship to said air openings, and valve actuating means connected to said valve member.

2. A combination, as defined in claim 1, wherein said valve member is a bar having spaced openings therein, the spaces between said bar openings overlying said air openings, and said bar is movable to bring said bar openings into alignment with said air openings in said panel.

3. A combination, as defined in claim 1, wherein said actuating means comprise a cam element operatively engaging said valve member to effect displacement thereof, and spring means secured to said valve member and yieldably opposing said displacement.

4. A device for use in an accordion, comprising the combination of a sound reflecting panel interposed between the treble section and the bellows of said accordion, said panel having air openings therein, a valve member movably secured in overlying relationship to said air openings, and valve actuating means operatively connected to said valve member.

5. A device for use in an accordion comprising the combination of a panel interposed between the treble section and the bellows of said accordion, an acoustic shell integrally formed in said panel, said acoustic shell having an air opening therein, said panel having a series of air openings therein, and valve means secured to said panel in overlying relationship to said panel openings and selectively movable to progressively expose said panel openings.

WILSON W. POMPILI.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2145,530 Rush Jan. 31, 1939 2,230,162 Lidblom Jan. 28, 1941 2,434,441 Seybold Jan. 13, 1948 2,460,408 Babicky Feb. 1, 1949 2,502,085 Frontalini Mar. 28, 1950 2,527,912 Bugari Oct. 31, 1950

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