US2220225A - Piano construction - Google Patents

Description

Nov. 5, 1940. c. FARNY PIANO CONSTRUCTION Filed Dec. 14, 1938 2 Sheets-Sheet l INVENTOR.

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- Nov. 5, 1940. c. FARNY 2,220,225

PIANO CONSTRUCTION Filed Dec. 14, 1938 2 Sheets-Sheet 2 INVENTOR. ('fK/L fiR/VK Patented Nov. 5, 1940 PATENT OFFICE 2,220,225 PIANO CONSTRUCTION Cyril Farny, St. Charles, 111., Rudolph Wurlitzer Company,

a corporation assignor to The Cincinnati, Ohio,

Application December 14, 1938, Serial No 245,573

5 Claims.

This invention relates to a piano construction and particularly with respect to the smaller type of piano wherein it is desired to combine economic construction with improved tonal qualities.

It is well known that in the smaller type of piano, such as the so-called spinet .or miniature, the acoustical properties do not favorably compare with the larger or standard pianos, such as the so-called grand piano. It is also well understood that one of the difficulties in the path of economically producing pianos lies in the expense inherent in the building and finishing of the piano casing-acquiring the highest type of cabinet work and finishing, involving both time and space.

It is the object of this invention to produce a piano having a casing so designed and constructed as to materially improve the acoustics of the piano while at the same time permitting it to be more economically produced as well as providing style and finish which will be highly attractive.

This is accomplished by so constructing the piano case as to embody a tone mixing chamber having certain desirable reflecting and vibrating properties in association with the sounding board. Instead of the casing being comparatively open, as is common in the usual construction, whereby the sound waves are dissipated and vibration sets in between the abutting but unconnected parts,such as the hinged top and front panel,the structure herein provides a completely encased tone chamber having no opening other than of proper and specially designed size which may be in the form of a grille or grilles preferably located in the bottom frame. The sounding board contained within the tone chamber constitutes a vibrating member with one face thereof exposed at the back, but transmitting vibrations on both sides thereof including the interior of the tone chamber. The sound waves set up by the sounding board within the chamber, instead of being dissipated through various scattered openings in the usual piano casing, are mixed and concentrated therein with a suitable opening or openings through which they may pass. Thus, such chamber is resonant to the lower tones and harmonics which strengthens the fundamental tone. This eliminates rumbles and vibrations resulting from escaping sound waves, and incidentally controls and regulates the air columns set up within the chamber, resulting in the desired richness of tonal quality.

To further enhance and improve the tonal quality, in addition to the completely enclosed tone chamber, the casing is built of a lighter plywood than is commonly used, and over which a sound filtering material such as fabric, leather or a suitable composition, is stretched. It has 5 been found that by thus covering the casing, the acoustical advantages thereof are further enhanced in that any vibration thereof, particularly the higher more penetrating partials, is filtered and the tone chamber is thereby sealed. The filtering effect of such covering eliminates harshness of tone, rendering it more mellow and bringing out the lower fundamentals.

Thus, the combination of the closed tone or mixing chamber with its sound wave control and the filtering cover therefor, results in an extremely pleasing and satisfactory piano tone having a more mellow, rich and deep tone quality.

As evidence of the effectiveness of such tone control and filtering, it is found that the hammers of the piano action may be initially harder than is permissible in the ordinary piano construction. Thus, it is not here necessary to needle the hammers to such an extent as to soften them under the so-called process of tone regulation with the result that they eventually return to their normal hardened state resulting in the tonal quality being later adversely affected. But on the contrary the structure herein permits them to be used at nearly their original hardened state and still have the desired softened tone quality.

Other improvements in the tonal qualities of this construction result from the form and arrangement of the end panels which instead of being the usual fiat boards in an upright piano, are generally curved at their forward edges to provide a concave inner surface creating an air column which contributes to the acoustical properties both by reason of the form and also by reason of being exteriorly covered by the filtering material. Furthermore, there results a reflection of the sound waves by the generally curved surfaces which causes the chamber to become a tone mixer.

Another feature of the structure which materially adds to the acoustical properties is the provision of a single unit with a concave inner surface forming the top and front panel instead of the usual separate and hinged top and front panels. This is true particularly wherein the front panel extends forwardly at a sloping angle providing an ideal tone reflector acting to direct the tone downward toward the tone control open- 2 ing of the grille. This structure thereby adds to the mellow, deep richness of tone, and in conjunction with the end panels acts as a tone resonator.

From the standpoint of economy considerable saving is effected in the construction in that the casing may be preferably constructed of a comparatively light plywood. It has been found that the best tonal quality is achieved by using a resonant wood, such as fir plywood. The thinness of the plywood which may be used in this construction results in a decrease of both the weight and cost while at the same time the casing is more rigid. This rigidity results from the completely closed and rigid tone chamber formed with no loose panels, tops or hinged parts.

The flexible covering material gives a most pleasing and desirable finish which does away with the expense, time and labor of highly finishing the'panels as is the usual practice. Thus, the flexible covering becomes an important and effective part of the construction, in addition to providing a filtering, mellowing and softening effect on the tone qualities of the instrument by reason of its sound absorbent qualities. Not only does such cover permit of more economical construction as well as enhanced appearance of the instrument, but so improves the tonal qualities as to render them more nearly of the quality of larger instruments. Such covering also goes far toward permitting of the original hardness of the hammer, reducing the amount of the usual process of tone regulation, through elimination of the higher harmonics.

The invention, therefore, involves the structure of the instrument primarily resulting in improved tonal qualities, economic production and unusual appearance, all resulting from the rigid structure having the closed tone chamber and a single opening; the reflecting and vibrating properties; the filtering effect of the covering material and the reduction of the process of tone regulation. in respect to the keys.

Another feature of the invention resides in the construction of the fallboard which has inherent advantages both as to economic construction, as well as the space required for its operation. One of the principal advantages of this construction of fallboard lies in its tongue and groove mounting at the ends for guiding it from open to closed positionsuch as will permit of shrinkage and expansion while at the same time more effectively guard against dust and dirt entering the casing. Because of the mounting of the individual wood strips upon a flexible support, difficulties of warpage heretofore present in the usual fallboard, are removed and any tendency toward excessive vibration of the wood parts is counteracted. This construction also permits of the incorporation of a music rest. with the fallboard which will give the desired height to a music panel in association with the front panel of the casing. Its flexibility and manner of operation also eliminates danger of finger pinching by reason of the weight and over center dropping of the usual rigid fallboard construction.

The full nature of the invention will be understood from the accompanying drawings and the following description and claims:

' Fig. 1 is a perspective view showing the complete instrument. Fig. 2 is a central vertical section through the casing taken on the line 2-2 of Fig. 1. [Fig 3 is a perspective view of the top and front panel removed. Fig. 4 is an enlarged section through the top and front panel, taken on the line 4-4 of Fig. 3. Fig. 5 is a perspective view of one of the side panels removed. Fig. 6 is an enlarged section through the side panel taken on the line 6-45 of Fig. 5. Fig. 7 is an enlarged sectional view of the fallboard. Fig. 8 is a section taken on the line 8-8 of Fig. '7.

In the drawings there is shown an instrument in the form of the usual upright piano structure of the spinet type comprising a keyboard Ill having a plurality of piano keys ll supported along the forward edge by the legs 12 and extending rearwardly into the casing. The piano casing is comprised of an integrally formed unit forming the top and front panels, as shown in Figs. 3 and 4, together with a sounding board, front panel and bottom board. More specifically the unitary top and front panels comprise the portions indicated at l3 and II, respectively, both formed from a single plywood board bent to provide a curved portion at I5 so that the top panel l3 extends horizontally over the top of' the piano while the front panel l4 extends at an angle downwardly therefrom toward the keys. The rear edge is reinforced by a top filler l6 and the lower edge by a bottom filler ll, whereas the curved portion I5 is reinforced by a moulding l8.

Secured over the exposed surface of the plywood there is a flexible fabric covering, indicated at l9, which may be of any suitable material, such as Fabrikoid, leather or an imitation leather material. The flexible covering l9 may be stretched thereover to present a smooth finish by either gluing it to the plywood or by carrying it around the edges thereof and tacking or securing it in any suitable manner so as be to evenly stretched to give a finished appearance, although unsecured intermediate its edges. This structure comprises what may be termed the top unit.

The sides of the piano casing comprise the side panels or units shown in Figs. 5 and 6. Each of these units is built up of a plywood board 20 having a curved moulding 2| joined along the forward edge thereof so that the forward edge of the unit is generally curved in cross section. The vertical wall of the unit is likewise covered by a flexible material 22 of the same character as above mentioned with respect to the top unit and which may be secured in any suitable manner thereover to present a finished appearance. The top of the unit comprises a wooden cap 23 perma nently secured to the top of the unit which may be covered, but preferably is left in the wood finish. Each unit is provided with arecess 24 for receiving the key blocks 25. The lower edge of the unit may be finished with a decorative overlay strip indicated at 26 of wood finished veneer or having any other suitable finish, said strip being secured over the flexible covering.

The third unit of the piano casing comprises a bottom panel 21 which is likewise of a veneer structure covered by a flexible material as above described,'to match that of the top and side units. The bottom edge of the front panel is provided with a continuation of the decorative overlay strip 28, preferably matching the corresponding strip 26 of the side units. Centrally located in the bottom panel, there is a grille opening 29 with which are associated vertical decorative and finishing strips 30 terminating at their lower end in the pedal block 3!. Whereas there is herein shown for purposes of illustration a single centrally positioned grille opening, such openings may be of any desired number, size or configuration, or located at any other suitable place in the casing as may be most desirable.

The fourth unit of the structure comprises the bottom board 32, and the fifth unit the sounding board 33 of the usual structure. The piano action is not illustrated other than being indicated by the hammer 34.

The triangular openings occurring between the downwardly sloping top panel M of the top unit and the end units, is closed by a suitable triangular end piece 32'.

In keeping with the flexible covering of the first three units above described there is provided a flexible fallboard shown in Figs. '7 and 8, for closing the piano keys when not in use. The fallboard likewise has a flexible covering along its bottom surface as indicated at 33' which supports and flexibly joins together a series of laterally extending fallboard mouldings 34, the ends of which slidably extend into the oppositely disposed grooves 35 in the key blocks 25 so as to permit the fallboard to slide relative thereto into open and closed position.

The fallboard is provided with a rib 36 along its forward edge to provide a music rest when in protracted position in conjunction with the upwardly sloping surface of the front panel 14. By reason of the tongue and groove sliding mounting of the fallboard, only a slot in the forward portion of the piano need be provided through which it moves, which is virtually closed and substantially sealed against the escape of sound waves or the entry of dust, dirt and the like.

From the foregoing description of the structure, it will be apparent that the piano action, in addition to the usual exposed sound board in the rear and the bottom board, is made up of four units, 1. e., the top unit, the two side units and the bottom panel. As distinguished from the usual piano structure, they are all securely and semi-permanently connected so as to provide a sound mixing chamber, as indicated at 31. Said chamber is further sealed by the flexible covering with the exception of the exposed sounding board, bottom board, and the small decorative side panel caps 23.

The structure embodying the several units semi-permanently secured together by screws or the like makes for a more economical structure and also eliminates vibration between parts of the casing by reason of its rigidity. The structure furthermore and particularly wherein the flexible covering is employed, seals the mixing chamber 3! against the escape of the sound waves or tone other than through a prescribed opening, such as the grille 29. Thus, the tone quality of the piano may be controlled. The flexible covering in addition to sealing the chamber, other than exterior finish which not only makes the instrument attractive in appearance, but effects considerable saving in time, expense and storage space in its production.

The invention claimed is:

1. A piano casing comprising a sounding board and a bottom board, a bottom panel, end panels having a general internally curved concave surface, a unitary top and front panel structure rigidly secured thereto, the front panel being curved downwardly from the top panel at an angle, and a sound emitting opening in the bottom panel positioned oppositely said sounding board to emit the sound waves created by the sounding board and reflected by the curved and angularly extending front panel and the generally curved inner surfaces of the end panels.

2. An upright piano having a casing comprised of an exposed sounding board at the rear thereof, a pair of end panels formed with a generally rounded forward portion and a cap member covering the top thereof, a keyboard extending laterally from said end panel units and partially supported thereby, a top and front panel unit supported over the upper edge of said sounding board between the end panel units, the front panel portion thereof extending downwardly at an angle to adjacent said keyboard, a bottom panel unit secured below said keyboard between the end panel units and having a grille opening therein, said keyboard having a pair of connecting sheet for retaining said mouldings adjacent each other, and flexible sound dampening and finishing covering secured over the exposed surfaces of said units.

3. A piano casing comprising a sounding board, a bottom board, a bottom panel and end panels fiected by said bottom board and flexible cover units and having a grilled opening therein, and a flexible sound dampening and finishing covering secured over the exposed surfaces of said units.

5. A piano easing having a sounding board, a bottom board, bottom and end panels, and a top and front panel, said panels and boards being rigidly secured to each other to form an enclosed in conjunction with the grilled sound emitting opening below said keyboard, and a flexible sealing material extending over the exposed surfaces of said panels to provide an exterior finish therefor and deaden the vibration thereof.

CYRIL FARNY.

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