US2027969A - Piano sounding board - Google Patents

Description

Jan. 14, 1936.

H. FiscHER 2,627,969

PIANO SOUNDING BOARD Filed Sept. 9, 1953 @www Patented Jan. 14, 1936 Application September 9, 1933, Serial No. 688,763

UNITED STATES PATENT GFFICE 3 Claims.

My invention relates to an improvement in sounding boards and is applicable for example to piano sounding boards. Gne object is the improvement of the vibration characteristics of a piano sounding board, for example by conveying the vibration from the bridge oi the sounding board out into the free and open part of the board. This effects an improvement in the tone of the sounding board and therefore of the piano and is a method oi even tone distribution. Another object is the improved supporting or reinforcing means for a piano sounding board, including for example forming the reinforcing ribs with chamiered portions having a delinite relation to the location of the bridge or bridges on the sounding board. Other objects will appear from time to time in the course of the specification and claims.

I illustrate my invention more or less diagrammatically in the accompanying drawing, wherein- Figure l is a plan View;

Figure 2 is a section on the line 2-2 of Figure 1;

Figure 3 is a section on the line 3 3 of Figure 2; and

Figure 4 is a View of the piano and sounding board from below.

Like parts are indicated by like symbols throughout the specification and drawing.

A generally indicates any suitable outer frame or supporting means or housing of a piano, it being understood that the piano details do not ci themselves form part of the present invention. I illustrate for example forward legsY A1, a rear or end leg A2, for supporting the piano, and the usual keys A3.

B is the sounding board proper of the piano, the board being of any suitable wood or vibrating material, However, I prefer to employ spruce. Positioned above the sounding board is the bass bridge generally indicated as B1 and the treble bridge generally indicated as B2, the treble bridge B2 extending substantially across the entire width of the sounding board. Any suitable wires B3 may be employed, secured in any suitable fashion and operated upon by any suitable percussion mechanism responsive to movement of the keys A3. As such features do not of themselves form part of the present invention they are not herein shown in detail.

Positioned upon the upper surface of the sounding board B is a vibration distributing member generally indicated as C which may be a relatively thin and irregularly shaped piece of wood, for example spruce, which is securely fastened, cemented, or glued to the sounding board so that the two are in effect one piece. Preferably, both sounding board and the extra vibrating or vibration distributing member are made of the same wood, namely spruce. Preferably, the grain of the part C is parallel with the grain of the sounding board B, the grain in both cases extending transversely across the axes or longitudinal extensions of the strings B3. The member C underlies the treble bridge B2, which may be secured to it and through it to the sounding board B. It includes a plurality of portions forwardly extending from the bridge. I illustrate for example an end portion C1, and intermediate extensions C2, C3 and C4.

In effect, what I am doing is to thicken the sounding board proper and to provide thickened portions which extend from the bridge out into the open body or expanse of the sounding board, these thickened portions being free to vibrate with the sounding board and being of parallel grain therewith. In practice the eiTect is to distribute Vibration throughout the sounding board and to cause the sounding board aseJ whole to vibrate to obtain the maximum strength and purity of tone in response to the vibration of the wire or wires struck by the percussive mechanism.

I also iind it advantageous o chamfer or thin the plurality of strengthening ribs employed for the bottom of the sounding board. I illustrate for example a plurality of ribs D chamfered at the ends as at D1. It will be noted that the chamfered end portions are oi varying length and the higher intermediate portions D also are of varying length, the treble bridge B2 extending across the thickest portions of the ribs D.

It will be realized that whereas I have shown a practical and operative device, nevertheless many changes might be made in the size, shape, number and disposition of parts without departing from the spirit of my invention. I therefore Wish my description and drawing to be taken as in a broad sense illustrative and diagrammatic rather than as limiting me to my specific showing.

The use and operation of my invention are as follows:

In my device I employ the conventional piano sounding board or its equivalent, which I form of spruce. I find that the tone and vibration distribution are very much improved if, instead of having a flat sounding board or a sounding` board of uniform thickness, I associate, with the bridges or with one of the bridges, a thickened portion, an extra vibrating portion, generally indicated as C, having parts, such as C2, C3, C4, which extend outwardly away from the. bridges, and which tend to lead or distribute the vibration caused by the hammers on the strings, out into the body of the sounding board. In practice I make the bridges of maple, the supporting or reinforcing ribs D of spruce and the sounding board B and the extra vibrating portion C also of spruce. In effect, the member C is a thickening of the memberB, being cemented or glued to it and under some circumstances this thickening might be obtained by simply carving out or reducing the thickness of the sounding board B. I nd it easier, however, and more practical, to obtain the desired variation in thickness by adding the Vibrating portion C.

I claim:

l. In combination with a piano sounding board, a bridge, wires associated with said bridge and a layer of Vibration transmitting material interposed between said bridge and sounding board and firmly secured to said sounding board, both sounding board and layer being of wood, the grain of both extending, in

general parallelism, transversely across the wires.

2. In combination with a piano sounding board, a bridge, wires associated with said bridge' and a layer of vibration transmitting material interposed between said bridge and sounding board and firmly secured to said sounding board and abutting thereagainst, throughout the entire area of said layer, both sounding board and layer being of Wood, the grain of both extending, in general parallelism, transversely across the wires, said layer including a plurality of projections extending transversely of the wires.

3. In combination with a piano sounding board, a bridge, wires associated with said bridge, and a layer of vibration transmitting material interposed between said bridge and sounding board and abutting against and iirmly secured to the sounding board, said layer being firmly secured, throughout its area,' to said sounding board, said layer including a plurality of projections extending outwardly away from the bridge, the sounding board and said layer being formed of the same wood, the grain of both extending in general parallelism.

HERMANN FISCHER.

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