US1218019A - Piano sounding-board. - Google Patents

Description

R. THOMAS.

PIANO SOUNDING BOARD.

APPLICATION FILED MAR. 4. 1911.

1 ,21 8,0 1 9. Patented Mar. 6, 1917.

2 SHEETS-SHEET l.

Aix

H. THOMAS.

PIANO SOUNDING BOARD.

APPLICATION FILED MAR. 4, 1911.

1 ,21 8,01 9. Patented Mar. 6, 1917.

2 SHEETS-SHEET 2.

nillillTliD STATES REINHOLD THOMAS, OF BROCKPORT, NEVI YORK.

PIANO SOUNDING-BOARD.

Application filed March 4, 1911.

'o all whom it may concern:

Be it known that I, RurNiroLD THOMAS, of Brockport, in the county of Monroe and State of New York, have invented certain new and useful lmprovements in Piano Sounding-Boards; and I do hereby declare the following to be a full, clear, and exact description of the same, reference being had to the accompanying drawings, forming a part of the specification, and to the reference-numerals marked thereon.

My present invention has for its object to provide a new and improved sounding board for musical instruments and one particularly adapted to be used in connection with pianofortes by means of which the general quality or tone of the instrument as a whole may be improved by increasing its resonant power. To these and other ends the invention consists in certain improvements and combination of parts, all as will be hereinafter more fully described, the novel features being pointed out in the claims at the end of the specification.

In the drawings:

Figure l is a rear elevation of an upright piano showing the frame, and illustrating a sounding board embodying my invention arranged thereon;

Fig. 9. is a rear elevation of the soundingy board removed from the frame.

Fig. 3 is view in front elevation of the sounding board arranged on the frame;

Fig. l is a transverse section on the line iX-4X of F ig. 3;

F 5 is a transverse sectional view taken in the direction of line X-x of Fig. 2, showing the curved forming surface with the sounding board and ribs pressed thereagainst in the process of construction; and

Fig. 6 is a transverse sectional view on the line (5X-6X of Fig. 2, showing the method of attaching the bridges to the sounding board.

Similar reference numerals throughout the several figures indicate the same parts.

In carrying out my invention I attach the supporting ribs to the sounding board in such manner that the board is given an arched form by curving it from its edges toward the center, and Iso unite the parts that both the board and the supporting ribs retain all of their original resonant qualities, the fibers of the sounding board and supporting ribs being so changed from their normal state that their resonant qualities are Specification of Letters Patent.

Patented Mar. 6, 1917.

Serial No. 612,240.

greatly improved, thereby giving the highest ellieiency of vibration.

Various methods may be adopted for accomplishing' this purpose, and the n sans illustrated :for carrying out the present embodiment of the invention, contemplates the ,use of a forming' surface or table l, (lished as shown, curving upwardly and outw rdly from its center. A board 2, composed of several strips glued together at their edges, is taken in its usual finished and thoroughly dry condition and laid upon the table on which at this time it is only supported at its edges. The ribs 3 in their finished and dry state are then arranged on the top or upper surface of the board, suitable cement er glue being applied between the supporting ribs and the face of the board 2. Pressure is then applied to deflect the entire surface of the sounding board, and sink it into intimate contact with the form or table l and at the same time to curve or bend the ribs correspondingly, such pressure being obtained, in the present instance, by means of the gluebars a which engage the -various supporting ribs at different points, andserve to force the sounding-board and supporting ribs downardly until they assume the same curvature as that of the forming surface or table l. Pressure is maintained until the cement or glue is hardened, which afterward serves to hold the supporting ribs and sounding board in the crowned or arched form by reason of the fact that the two surfaces, namely, those of the sounding board and of the supporting ribs, coact one against the other, but being in fixed engagement each part acts to hold the other in the set position, thusl counteracting the normal tendency of each part to straighten.

While the employment of glue bars, as herein shown, is a convenient and ready method of obtaining the desired pressure on the sounding board, it will be obvious that other means might be vused to the same end, whereby the necessary force may be obtained to hold the ribs and sounding board properly deflected while they are being attached. In practice I find that the sum of the pressures required on the glue bars is approximately 8,000 pounds, and in some instances it is even greater.

The apparatus employed for accomplishing this is not essential as various means may be used to hold the parts deflected until if the glue or other fastenings which 'may be used have been applied to effect a union between the board and the ribs while both parts are deflected. This flexing of the board and ribs out of their normal positions, whether curved or flat, causes a longitudinal sliding movement of each part relatively to the other in one direction. ifi. corresponding movement in the reverse direction will occur if the parts arc released without being united, but this is resisted by the glue bars, or forming apparatus, by which the board and ribs are held until the glue has hardened. lll hen an intimate union or connoction has been established the board as a whole is removed and the normal tendency of the parts to assume their original shapes, u

which previously has been resisted by the forming apparatus, is transferred to thc means employed for uniting them. The board proper endeavoring to straighten out is resisted by the ribs from which it cannot free itself. Each of the ribs likewise tend ing to assume its normal shape, and being unable to slide upon or detach itself from the board, acts through the resistance thus encountered and produces a stress in the board proper. llhe union between the two parts counteracting the forces exerted by each serves to hold them in a state of stress which is imparted, more or l ss, to every fiber of the board and produces liveliness and susceptibility to sound waves.

After the supporting ribs are secured to the sounding board, the position of the latter is reversed on a second forming" surfaceor table 5, which is arched from its center outwardly and downwardly toi'vard its edges, to conform with the concave rear surface of the sounding board. llllhile in this position, as shown in lig. 6, the bridges i' and 8 are secured, preferably being glued or cement-ed to the surface of the smindingI board and held in proper relation thereto by the glue bars 9. rlhe bridges are suitably out away on their lower faces to conform to the cuivature of the sounding board.

As soon as the bridges have been secured the sounding board is removed from the support 5 and mounted on the piano back, as shown in Figs. l and -l-, by gluing its edges securely thereto. The board thus mounted is firmly held against all internal stresses to which it may be subjected by atmospheric changes or other causes, and it is likewise held in its arched form against the great strain imparted to it by the strings bearing` ipon the bridges, the union between the board and the ribs serving effectually to prevent the strain of the strings from returning the board from its arched form to a flat position.

With the present construction, it is possible to provide an exceedingly sensitive sounding` board, greatly increasing the voli,ais,oie

ume of the tones and improving their richness and sustaining qualities. lt has been determined by actual use of a large number of pianos. equipped with sounding boards embodying the invention herein set forth, that such sounding boards sustain vibrations capable of being heard by the unaidcd ear during a. period of at least one-third longer duration than manufacturers and musicians have heretofore believed it possible to obtain with any sounding board umler the most favorable conditions. rEhe tones produced by the present sounding board are very sonorous, and different tones are perfectly blended. 'llhe higher notes of the scale, which are usually sharp and hard', are given a defined ring and brilliancy, while the lower notes reverberate with a considerable and noticeable depth and purity.

W ith a sounding board such as described, l may also employ means whereby the qu'ab ity or pitch of the fundamental tones produced may be altered, comprising a sounding post l() which is preferably circular in crosssection and has a reduced central portion 111. rlhe size of the post is, however, a matter of experiment to be determined according to the qualities of the sounding board itself and the effect it is desired to produce by its use. llt is also a matter of experiment as to thc exact placer at which to locate the post, but in general it may be stated that it is preferably arranged'so as to form a nodal point, somewhere near the center of the sounding board. rl`he post is connected to the outer surface of the board and to the piano back or case, as shown in Fig. e, by gluing it to the respective parts, and is for the purpose of controlling the location of the nodes occurring in the vibration of different parts of the sounding board in re spouse to different notes or combinations of notes, which may be sounded.

in the illustrations l have sounding board as applied to an upright piano, but it will of course be understood that it is equally well adapted for use in grand pianos, and in connection with other musical instruments.

l claim as my invention:

l. r1lhe method of constructing sounding boards which consists in supporting` the fiat board on a concave surface, positioning. supporting ribs having straight engaging faces on top of the board with glue between said faces of the ribs and the board, applying pressure to the ribs and board to cause them to assume the curvature of the supporting surface, and maintaining the parts thus flexed until the glue hardens and the ribs are aflixed to the board to retain the latter flexed when removed from the supporting surface.

2. The method of constructing sounding boards which consists inplacing a plurality shown the of fiat ribs in Contact With a flat board with glue between the board and ribs, arching the board and ribs, and holding the board and ribs in such arched position until the glue hardens.

3. The method of constructing sounding c boards which consists in applying the board 15 dens and the ribs are aflixed to the board.

4l. The method of constructing sounding boards which consists in placing a plurality of flat ribs in contact With a fiat board, arching both the board and the ribs and securing the board and ribs together in such arched position.

5. The method of constructing sounding boards which consists in placing a plurality of ribs in contact with a board, arching both the board and the ribs, and securing the board and ribs together in such arched position.

REINHOLD THOMAS.

Witnesses:

HENRY G. RUNNE, CAMILLE BORDWELL.

Copies of this patent may be obtained for ve cents each, by addressing the Commissioner of Patents, Washington, D. C.

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