US1694789A

US1694789A - Piano

Info

Publication number: US1694789A
Application number: US290189A
Authority: US
Inventors: Floyd S Muckey
Original assignee: JOSEPH F O BRIEN; JOSEPH W GOODWIN; MUCKEY PATENTS CORP
Current assignee: JOSEPH F O BRIEN; JOSEPH W GOODWIN; MUCKEY PATENTS Corp
Priority date: 1919-04-15
Filing date: 1919-04-15
Publication date: 1928-12-11
Anticipated expiration: 1945-12-11

Description

Dec` ll, 1928. 1,694,789

F. s. MUKEY PIANO Filed April l5. 1919 4 Sheets-Sheet l -llllllllllllllllIllllllillll @www 20% 52%M QM atto-maui Sly-... mm

u vento/c F. S. MUCKEY Dec. ll, 1928.

PIANO Filed April 15. 1919 4 Sheets-Sheet 2 F. S. MUCKEY PIANO Filed April l5. 1919 4 Sheets-Sheet 3 Dec. 11, 1928.

Dec. ll, 1928. 1,694,789

F. s. MUCKEY PIANO Filed April 15. 1919 4 sheets-sheet 4 T5231? m'rarnrhfffff Patented Dec. l1, 1928.

UNITED `STATES .1,694,189 PATENT OFFICE.

FLOYD S. MUCXEY, OF NEW YORK, N. Y., ASSIGNOB, BY DIRECT AND MESNE ASSIGN- MENTS, OF ONE-TENTH TO JOSEPH F. OBRIEN, OF WEST NEW YORK, NEW JERSEY; THREE-'LENTES TO JOSEPH W. GOODWIN, 0F RICHMOND HILL, NEW YORK; AND SIX-TENTHS T MUCKEY PATENTS CORPORATION, A CORPORATION OF NEW YOBK.

PIANO.

Application led April 15,1919. Serial No. 290,189.

This invention relates to improvements in ianos.

ere are` three prerequisites to obtaining the best tone quality in any musical instrument, namely: (l) the fundamental of each composite tone produced should at all times have greater intensity than any other partial tone of the composite tone, (2) the partial tones of each composite tone should gradually diminish in intensity as they rise in series from the fundamental, and (3) all the partial tones of eac-h composite tone should continue without any intermittence and with the same relative intensity to one another during the interval that, they composite tone continues to be heard. In many, if not all, of the composite tones heretofore produced by the sounding boards of pianos the fundamental does not at all times have greater intensity than any other partial tone of the composite tone, and the fundamental and other partial tones of the composite tone` do not continue with the same relative intcnsit-y to one another during the interval that the composite tone continues to be heard, `but on the contrary the fundamental diminishes in intensity and dies out much more quickly than the overtones. This is particularly noticeable in the middle andv the upper part of the scale. Furthermore, the fundamental as well as each of the other partial tones, at certain periods, either stops entirely for a short time or is much weaker in intensity.

It is, of course, desirable to approach this best tone quality hereinabove defined as closely as possible, and theprincipal objects of my invention are (l) to produce a piano in which the strings will originate and the sounding board reproduce composite tones in which the low partial tones viz, the fundamental and first overtone will, at all times, have greater intensity than any other partial tone of the composite tone, (2) to produce such tones inwhich the partial tones gradually diminish in intensity as they rise in series from the fundamental or first overtone, and (3) to produce such composite tones in which the partial tones continue in regular and unbroken periodic sequence during the interval that the composite tone continues to be heard and Without any intermittence in the relative intensity of the sound waves comp-rising the tone. Tones having some or all of such characteristics will be of more pleasing quality.

Another obj ect of my invention is to ca-use the production of al sounding board which will be sufficiently sensitive to proportionately and with substantial accuracy reproduce substantially all the vibrations that are transmitted to it from the strings through the bridges. Such a sounding board should be sufiiciently thin to accurately respond to the fundamental and first overtone which I shall hereinafter call low partial tones; it should be of substantially uniform thickness and without ribs and should also be of substantially counterpoised texture. A board having these characteristics is more responsive' to such low partial tones than the sounding boards heretofore employed as the various elements common to other sounding boards and which are eliminated, cause interference with responsivenessto and roduction of the low partial tones. Suc a sounding v board will reenforce composite tones having the low partial tones of relatlvely stronger intensity than any of the higher overtones and I shall hereinafter term such a sensitive board as a predominant low partial tone sounding board and a board which is not so sensitive as a predominant higher overtone sounding board.

In the preferred embodiment of my invention I employ such a predominant low partial tone sounding board in combination with a support consisting of sound-posts and a secondary sounding board spaced from the primary board and connected thereto by such sound posts.

Another object of my invention is to provide between the primary and secondary sounding boards a resonance cavity of a shape which will concentrate and further reinforce the tones produced by the adjacent sides of the board and particularly the fundamental and lower overtones of the composite tones.

Another object of my invention is to so position the sound posts between the boards as to cause such sound posts to cause that portion of the sound board between the lridge and the connection of such board to the frame at the opposite side of the osts to act as a lever in the transmission o vibrations from the primary board to the secondary board and in the transmission -back .to the primary board of the res onding impulse caused by the resilience o the secondary board.

In the accompanying drawings like characters of reference denote corresponding parts throughout all the views. of which Fig. l is a vertical transverse section of a piano embodying my invention;

Fic. 2 is a front elevation of a primary Asoun ing board with a string-supporting plate and strings mounted adjacent thereto and showing in dotted lines the positions of the sound posts, and frame uprights and the shape of the resonance cavity;

Fig. 3 is an elevation with the back removed and part of the frame members being shown in section;

Fig. 4 is a section on the line 4-4 of Fig. 3;

Fig. 5 is a vertical section through the sounding board of my piano.

Fig. 6 is a view in plan of a sound board preferably employed by me, a part of the top layer being broken away to show the cross graining of the two layers Fig. 7 is an enlarged view of the upper corner of a modified form of sounding board and a modified bridge for the high treble strings;

Fig. 8 is a section on the line 8-8 of Fig. 7

Fig. 9 is an enlarged section on the line 9-9 of Fig. 3.

Referring now to these drawings, my invention is here shown applied to an upright piano but, by suitable modifications in the frame and other parts, may be applied to grand pianos or other types. In these drawings, 1 indicates a primary sounding board mounted at one side of a frame comprising end uprifrhts 2 and 3; intermediate u

rights

4, 5, an 6 and wrest plank 7 and ottom beam 8. Said primary sounding board comprises what I shall term a predominant low partial tone board by which term I desire to include all boards or sounding elements which are adapted to segment favorably for the product-ion or reinforcement of composite tones in which the fundamental or the first overtone predominates with the higher overtones diminished in intensity in contradistinction to boards or elements which segment favorably for the production of composite tones having a predominance of higher overtones.

Such a sensitive sounding board must bo comparatively thin and the degree of thinness is determined by the requirement that the sounding board must also be rigid enough to retain its proper position when subjected to the pressure of the strings upon the bridges and to react quickly to the impulses it receives.

Practice has shown that boards of spruce 14 such as usually employed of appreciably over one-half inch in thickness segment favorably for the production of tones having a redominance of higher overtones, and mayl iie called predomlnant overtone boards while boards of such wood of less thickness segment favorably for the production of com site tones having a predominance of fun amental or the first overtone and may be thus called predominant low partial tone boards.

Applicant employs a predominant low partial tone sounding board which is not reinforced by ribs attached to it. I have built up a sounding board less than the required onehalf an inch in thickness from lammations or superposed layers of spruce Wood having the grains of each layer crossing each other at pro er angles, that is if two layers, 60% if) three layers, etc., and have crowned the same at the time of securing such laminations together. This produces a board which is sufficiently sensitive to accurately and proportionately reproduce all the partial tones, especially the lower partial tones, and is substantially counterpoised in its fibrous texture for it has substantially the same elasticity, rigidity and tensile strength in all directions on its surface and unmounted is substantially uniformly sensitive at all oints of its surface. Such a sounding boardD would not, however, in itself be rigid enough to support the pressure of the high tension strings against the bridges.

Such a predominant low partial tone sounding board when made of wood such as spruce would not, however, have in itself suffcient rigidity and resistance to support the pressure of high-tension strings against the bridge, and requires a support which will not, first, interfere with the proper and symmetrical segmentation of the board as do the ribs hereinabove referred to and, second, which will not so decrease the sensitiveness of the board to the large segmentation as to produce a predominant overtone board. I have overcome these difficulties, by providing for. such a board what I shall term a vibrating support.

In the preferred embodiment of my invention, I employ such a predominant low parv` tial tone board .in combination with a support consisting of a secondary sounding board 9 spaced from the primary board and connected thereto preferably by a plurality of suitably-disposed sound posts 10. 11 and 12.

I connect this secondary sounding board to the primary sounding board by such sound posts preferably at a plurality of points just below the bridges and between the same and the edge of the sounding board, two or more of such sound posts preferably being employed, as shown, adjacent to the long bridge 13 and one adjacent to the short bass bridge :Ihe string-plate 15 may be mounted in the .conventional manner at one side of the primary board and the strings 16 extend across the bridges 13 and 14 in the usual way to--`cajuse vibratlons of the strings to be transmitted to the sounding board, any suitable means being employed to vibrate the strings.

The positions of the

sound posts

10, 11 and 12 as hereinabovedescribed not only supports the )rimary board and enables it to withstan the high pressure of the strings, but causes any vibrations transmitted by a string through the bridge of the primary sounding board to be communicated -by the sound posts to the secondary board 9 which, as shown, is mounted at the outer side of

marginal boards

17, 18, 19 and 20 which form a frame therefor and are preferably provided with a depressed seat 21 for the said board which, as shown, is secured at its marginal edges to its seat by strips 22 and screws 23 but may be so secured in any suitable manner. en so arranged, it completely closes the back of the piano and is spaced somewhat from the

intermediate posts

4, 5 and 6 to permit free vibration intermediate its edges.

The transmission of vibrations to said secondary board 9 greatly enlarges the vibrating surface and increases the volume of sound produced by the piano, and the novel positions of such posts cause that portion of the sounding board 1 extending from the bridge to its attachment with the frame together with a post to act, in the transmission of such vibrations to the secondary sounding-board, as acomposite leverwith power exerted on the portion of the primary sounding-board 1 to which the bridge is connected, the fulcrum of the said composite lever bein at the point of attachment of the soundingoard with the frame.

The secondary sounding board 9, which also is a predominant fundamental sounding board of similar homogeneous text-ure is preferably left uncrowned and is arranged to cause a return or responsive resilientpressure through the sound posts to the primary board 1. In this way, any vibration' of the strings will be communicated throuvh the bridge to the primary sounding boardb 1, and in communicating this vibration to the secondary board, the primary board will, as aforesaid because of such positions of the sound posts, the portion of the sounding board 1 extending from the bridge to theattachment of the said sounding-board with the frame together with a post will act as a composite lever with power exerted on the portion of said primary board to which t-he bridge is connected. the fulcrum of the composite` lever being at the point of attachment of the said primary sounding-board to the frame and the said vibrations will thus be transmitted to the resilient or vibrating secondary sounding board which is in turn vibrated. Because of its elasticity, the secondary sounding-board gives a counter-impulse 0r opposite impulse and thereb not only causes a quicker recovery of tl'ie primary sounding board from the impulse of any particular vibration of a string, but causes an accelerated swing or vibration in the opposite direction, thus increasing the amplitude of vibration of thc boards and the volume of sound produced thereby.

The employment of a secondary sounding board suitably spaced as above set forth from the primary sounding board also forms intermediate such primary sounding board and the seconda sounding board a resonance cavity 24 which further reinforces lthe tones which are produced by the prim-ary and secondary sounding boards at the adjacent sides of such boards. To procure the most effective use of the resonance cavity so provided, I preferably have the spaces between the two boards completely enclosed except at the top of the piano which is left open to permit the discharge of the reinforced air waves therefrom. I also preferably shape the said cavity as far as possible to concentrate the sound Waves produced in such cavity near a restricted outlet 25. For this purpose of concentrating air waves near the outlet, I provide each corner of the bottomy of the piano with a block 26 having its

inner surface

27 or 28 which forms the boundary of the cavity curved from end to end. These blocks 26 ill in and round out the lower corners and such blocks, as well as side edges of the cavity, are preferably provided with a depressed groove 29 of semi-circular cross-section for the purpose of further concentrating air waves.' The `side walls of the cavity intermediate the outlet and the lower end thereof are also preferably provided with

blocks

30, 31, 32 and 33 having curved inwardly extending faces which project into the cavity, and are adapted to restrict the outlet and further concentrate contiguous to the outlet the air waves issuing therefrom. The intermediate posts which extend through the cavity 24 are preferably rounded' off at their corners, as shown in Fig. 4, so as to kpresent as little interference as possible to the reinforcement, conducting and concentration of sound waves by the said resonance cavity and the square inner tops of the corner posts are also preferably rounded otf as shown at 24 in Fig. 3. The intermediate posts are, as aforesaid, disposed centrally in the cavity and without touching either of the two sound boards on opposite sides thereof so that the sound waves produced in the cavity. are reinforced and concentrated and then discharged upwardly between the intermediate posts and between such intermediate posts and the end posts, an outlet 0r opening'25 being provided for this purpose. This out-let is preferably provided with a suitable cover 34 which may be hinged at its rear end, as shown, and preferably has a sound channel 35 to enable the conduction ot' sound waves to the front of the piano. I also preferably provide in this cover at the front edge thcreo't', a. series of discharge openings 36 to permit the discharge of air waves from the cavity therethrough when the cover is iu closed position.

.In Figs. 7 and R, I have shown a slightly modified form of sounding board in which the sensitiveness oi the primary sounding board is increased at the corner thereof on which the high treble strings are mounted by providing slots S7 and also by raising the end of the bridge 38 which supports the high treble strings and raising and thinning the same progressively toward the higher tones, thus enabling the highest tones to have the benefit of the. greatest leverage of the bridge in the transmission of their vibrations to the sounding board l and still balancing the gradually reduced pressure of the strings.

Having described my invention, I claim:

l. A sounding board for pianos having a ribless rear surface and of a thinness and rigidity to segment for the reproduction of composite tones having a predominance of low partial tones, a support. for the edges of said board, an additional elastic support arranged at the rear of said board and means for connecting said support and board distant Jfrom the edges thereof.

2. A sounding board for pianos of substantially counterpoised texture having a substantially smooth and ribless rear surface and of a thinness and rigidity to segment for the reproduction of composite tones having a predominance of low partial tones, a support for the edges of said board, an additional elastic support arranged at the rear of said hoard and means for connecting said support and board distant from the edges thereof.

3. A sounding board for pianos of substantially homogeneous texture, having a substantially smooth and ribless rear surface and composed of a plurality of superposed layers of Wood, said board being of a thinness and rigidity to segment for the reproduction of composite tones having a predominance oit low partial tones, a support for the edges of said board, an additional elastic support arranged at the rear of said board and means for connecting said support and board distant from the edges thereof.

4. A sounding board for pianos of substantially counterpoised texture and having a substantially smooth and ribless rear surface and composed of superposed layers of Wood having the grains of suoli layers crossing each other, said board being of a thinness and rigidity to segment for the reproduction of composite tones having a predominance of low partial tones, a support for the edges of said board, an additional elastic support arranged at the rear of said board and means for connecting said support and board distant from the edges thereof.

5. In a piano, the combination with strings and means for supporting and vibrating the same, of a sounding board of substantially counterpoised texture and having a substantially smooth and ribless rear surface, comprising superposed layers of Wood having the grains of such layers crossing each other, said board being of a thinness and rigidity to segment for the reproduction of composite tones having a predominance of low partial tones, means for transmittinfv the vibrations of the strinfrs to the boar suitable means for supporting said board at its edges, an additional elastic support arranged at the rear of said board and a lurality of posts connecting said rear sur ace between the edges of said board with said elastic support.

6. In a piano, the combination with strings and means for supporting and vibrating the saine, of a sounding board having a substantially smooth, ribless rear surface secured at its marginal edges, said sounding board being of a thinness and rigidity' to segment for the reproduction of composite tones having a predominance of low partial tones, means for transmitting the vibrations of the strings to the said sounding board, means for supporting said board at its edges, an additional elastic support arranged at the rear of said board and a lurality of posts connect-ing said rear sur ace between the edges of said board with said elastic support.

7. In a piano, the combination with strings and means for supporting and vibrating the same, of a primary sounding board comprising a sounding board having a substantially smooth and ribless rear surface and of a thinness and rigidity to segment for the reproduction of composite tones having a predominance of low partial tones; means for transmitting the vibrations of the strings to the said sounding board; means for supporting said primary sounding board at its edges, an elastic secondar sounding board independently supporte at the rear of said primary board and spaced therefrom and sound posts connecting said secondary sounding board and said primary sounding board to support the latter.

8. In a piano, the combination with strings and means for supporting and vibrating the same, of a primary sounding board comprising a sounding board having a substantially smooth and ribless rear surface and of a thinness and rigidity to segment for the reproduction of composite tones having a predominance of low partial tones; a bridge for transmitting the vibrations of the strings to the said sounding board; means for supporting said primary sounding board at its edges, an elastic secondary sounding board independently supported at the rear of said primary u board and spaced therefrom, and sound posts connecting said secondary sounding board and said primary sounding board to support the latter, said posts being ositioned adja cent to the bridge at the si e thereof opposite to the vibrated portion of the strings.

9. In a piano, the combination with strings and means for supportin and vibrating the same, of a rimary soun ing board having a substantial y smooth and ribless rear surface,

and of a thinness and rigidity to segment for the reproduction of composite tones having a predominance of low vpartial tones; means for transmitting the vibrations of the strings to the said primary sounding board, means for suitably supporting said primary board; an elastic secondary sounding board independently supported at the rear of said prima-ry soun ing board and arranged to form a closure for the rear of the piano spaced from the primary sounding board to provide a resonance cavity between such primary sounding board and said closure; said cavity having walls shaped to concentrate air waves near an outlet at one end thereof and sound posts arranged between the edges of said primary and secondary boards.

10. In a piano the combination with strin and means for supporting and vibrating t e same, of a primary sounding board of substantially counterpoised texture and composed of superposed layers with the grain crossing, said primary soundin board having a substantially smoothA an ribless rear surface and being of a thinness and rigidity to segment for the reproduction of composite tones having a predominance of low partial tones; means for transmitting the vibrations of the strin to the said sounding board, means for suitably supportin said board; an elastic seconda sounding oard independentl supporte at the rear ofsaid primary soun in board and arranged to form a closure for t e rear of the piano spaced from the primary sounding board to provide a resonance cavity between such primary sounding board and closure, said cavity having walls shaped to concentrate air waves near a restricted outlet at the top thereof, and sound posts arranged between the edges of said pri- -mary and secondary boards.

11. In a piano, thecombinationwithst and means for supporting and vibrating t e same, of a primary sounding board of substantially counterpoised texture and having a substantially smooth and ribless rear surface and of a thinness and rigidity to segment for the reproduction of composite tones having a predominance of low artial'tones; means for transmitting the vi rations of the strings to the board, means for suitably supporting said board at its edges; an elastic secondary sounding board independentl supported at the rear of said primary sounding board and being of substantially homogeneous texture and of a thinnessand rigidity adapted to segment favorably for the reproduction of composite tones having a predominance of low partial tones, said secondary board being arranged to close the rear of the piano to provide a resonance cavity between such primary sounding board and such secondary board and sound posts between said primary and secondary boards for vibratably supporting said rimary sounding board between its edges an transmitting vibrations between the two boards.

12. In a piano the combination with strin and means for supporting and vibrating t e same, of a primary soundin board composed of superposed cross-graine layers and of a substantially counterpoised texture and having a substantially smooth and ribless 'rear surface and being of a thinness and rigidity to segment for the reproduction of composite tones having a predominance of low partial tones; means for transmittin the vibrations of the strings to the boar means for suitably supporting said board at its edges, means for supporting said primary sounding board intermediate its edges and spaced therefrom, comprisin an elesatic secondary sounding board independently7 supported at the rear of said primary soun ing board and composed of superposed crossgrained layers and of substantial] neous texture and of a thinness an rigidity adapted to segment favorably for the reproduction of composite tones having a predominance of low partial tones and sound posts suitably disposed intermediate said primary and secondary boards.

In witness whereof, I have signed my name nto the foregoing specification.

FLOYD s. MUCKEY.

homo-