US2269783A - Piano - Google Patents

Description

Jan. 13, 1942. o. PETERSON PIANO Filed Marbh 16, 1940 Patented Jan. 13, 1942 PIANO Olaf Peterson, Rockford, 111., assignor to Haddorf Piano Company, Rockford, lll., a corporation of Illinois Application March 16, 1940, Serial No. 324,264

3 Claims.

This invention relates to piano construction, and particularly to those features which are. designed to control the character and volume of the tone. One object of the invention is to provide an auxiliary sounding board adapted to substantially amplify the volume of tone normally obtainable from a piano of a given size. Another object is to employ an already existing portion of the piano case as the auxiliary sounding board. A further object is to provide means for effectively transmitting vibration from both the treble and bass ranges to the auxiliary sounding board; and, more specifically, it is an object to furnish a relatively rigid connection between the main sounding board and the auxiliary sounding board for causing them to vibrate together. It is also an object of the invention to provide improved means for producing a satisfactory tone of amplified volume with a piano of relatively small dimensions. The invention consists in certain features and elements of construction in combination, as herein shown and described and as indicated by the claims.

In the drawing:

Figure 1 is a front elevation of a vertically strung piano of modern design embodying this invention, lower portions of the front wall or bottom board and of the pedal lyre being broken away to reveal features of the interior construction, and only a part of the strings being shown.

Figure 2 is a plan section taken substantially as indicated at line 2-2 on Figure 1, with the strings omitted.

Figure 3 is a detail section on a larger scale taken as indicated at line 3-3 on Figure 1.

In designing pianos of small dimensions, and particularly in line with the present trend toward low, vertically strung pianos in which the case extends only a short distance above the level of the keyboard, it becomes a problem to secure from the instrument a satisfactory volume of tone in view of the necessarily reduced area of the sounding board. This invention provides an effective solution of this problem by employing a wall of the piano case as an auxiliary sounding board. The drawing illustrates a vertically strung piano of modern design, such as that shown in U. S. Patent No. 2,056,352. The usual string plate I is mounted in front of the sounding board 2, with the strings 3 of the treble range and the strings 4 of the bass range secured over it in the usual manner. A bridge 5 is provided for the treble strings, and a bridge 6 supports the bass strings; as seen in detail in Figure 3, the treble bridge 5 is attached directly to the sounding board 2, but the bass bridge 6 in cludes an arm or web I having a foot-piece 8 by which it is attachedto the sounding board 2 at a distance inwardly from the edge of the latter. In accordance with the usual practice, it may be understood that both the plate I and the sounding board 2 are mounted upon the usual relatively heavy frame timbers of the case, which are not shown in the drawing.

The sounding board 2, of course, vibrates in sympathy with the strings when they are actuated by the hammer action, not shown, and the sounding board in turn sets up vibration of the air in contact with its entire area, thus amplifying the original tones of the strings in a well understood manner; and the present invention undertakes to increase this amplification of the tone by bringing into play an auxiliary sounding board, thus increasing the effective area from which sound waves are sent out into the room.

In the particular design illustrated the front wall of the piano below the keyboard, which is commonly termed the bottom board, is an outwardly curved panel 9 reinforced by a horizontally extending flange member 10 at its lower edge, and trimmed with molding strips II at its ends. The bottom frame member I2 of the case is provided with upstanding dowel pins l3 at widely spaced points in the width of the piano, and these pins engage registering holes in the flange member ID for positioning the panel 9. Bearing blocks M are arranged to act as spacers between the sounding board 2 and the four corners of the panel 9, as indicated in Figures 1 and 2; and, preferably, these bearing blocks are attached to the panel 9 so that when the latter is mounted in place, with the dowel pins l3 registered in the holes of the member l0, these blocks I4 will bear firmly against the face of the sounding board, and the panel may be held in position by the pressure of a pair of swinging bracket arms I5, I5 pivoted on the under side of the keybed I6 and formed with suitable shoulders to bear against the outer face of the panel 9 adjacent its upper edge.

For transmitting vibration from the strings and sounding board 2 to the panel 9, so that it may serve as an auxiliary sounding board, there is provided a tone post I1, specially formed of hard maple wood or equivalent material, which includes branched legs 11 and I'l having foot portions I'l and li which are shown secured to the bridges 5 and 6 by means of screws l8. The legs H and l'l converge outwardly to form an arch with a bearing point at [1 for contact with the panel 9. Since, in the form shown, the panel is curved in horizontal cross-section while its surface is made up of substantially straight vertical lines or elements, the inner face of the panel is provided with a bearing bar l9 extending vertically in position to engage the contact point H of the tone post I! so as to distribute vibration therefrom to the middle area of the panel 9. This middle area is stressed against the tone post I! by engagement of the rail III with the dowel pins l3, and by the inward pressure of the brackets [5 against the upper edge of the panel 9; and at the same time the corner blocks Mare pressed firmly against the sounding board 2. The points of attachment of the panel '9, at I3 and i5, are relatively remote from the bearing point li so that vibration may be efiectively transmitted from the sounding board 2 to the panel 9 through the connection afforded by the tone post l1. As seen in Figure 3, one foot I! of the tone post is secured directly to the treble bridge 5, and the other foot ll is anchored to the foot-piece 8, which supports the bass bridge 6 on the sounding board 2. Thus the vibrations of the sounding board are carried to the panel 9 substantially from the points at which they originate in the sounding board itself, namely, the bridges 5 and 6 through which the strings make their contact with the sounding board 2. It will be understood that in some cases it may be possible, or preferable, to connect the treble bridge and the bass bridge with the auxiliary sounding board 9 by means of separate tone posts suitably located, and that in some instances a tone post leading from only one of the bridges may secure the desired result by enhancing the power of either the treble or the bass range of the instrument. Both of these alternative arrangements are considered within the scope of this invention, but, as a general application of the principle, the illustrated embodiment transmits vibration from both bridges to the auxiliary sounding board.

As a result, the panel 9 is found toamplify the tone of the piano to a very substantial extent, so that a surprising increase of power, as well as a deeper quality of tone, is realized in a relatively small instrument. And the bowed or curved formation of the panel 9, in addition to enhancing the artistic appearance of the piano case, permits the panel to be locked in position under stress, so that it is held properly taut for performing its function as a vibratory diaphragm.

While there is shown and described herein certain specific structure embodying the invention, it will be manifest to those skilled in the art that various modifications and re-arrangements of the parts may be made without departing from the spirit and scope of the invention, and that the same is not limited to the particular form herein shown and described, except in so far as indicated by the appended claims.

I claim as my invention:

1. In a piano, in combination with a string plate, a sounding board, a treble bridge and a bass bridge both mounted on the sounding board, an auxiliary sounding board and a tone post having a single bearing against said auxiliary sounding board and including branched leg portions with means securing one of said legs to the treble bridge and means securing the other leg to the bass bridge.

2. In a piano, in combination with a string plate, a sounding board, a treble bridge and a bass bridge both mounted on the sounding board, an auxiliary sounding board and a substantially rigid arched member bearing against said auxiliarysounding board with the feet of the arch stepped respectively upon the treble and bass bridges at portions of the latter which are attached directly to the sounding board.

3. In a piano, in combination with a case, a string plate therein and a sounding board with a treble bridge and a bass bridge thereon, said case including an outwardly curved front wall, an arched tone post bearing against the middle area of said wall and having foot portions secured respectively to the treble and bass bridges, rigid bearing means disposed between marginal portions of said front Wall and the sounding board, holding means on the case engaging said Wall at points remote from the tone post stressing said Wall against said post and pressing its marginal portions against the sounding board with said rigidbearing means interposed.

OLAF PETERSON.

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