US1794550A - Sound board for pianofortes and the like - Google Patents

Description

March 3, 1931. SANDER 1,794,550

SOUND BOARD FOR PIANOF'ORTES AND THE LIKE File Feb. 5, 193 2 Sheets-Sheet l lave/awn Richard fla/uier Adar/2g.

R. SANDER March 3, 1931.

SOUND BOARD FOR PIANOFORTES AND THE LIKE Filed Feb. 5, 1930 2 Sheets-Sheet 2 Inventor Richard 56026567,

4 I I Abtorr-L z Patented Mar. 3, 1931 PATENT? OFFICE RICHARD SANDER, F CUBITYBA, BRAZIL SOUND BOARD FOR PIANOFOBTES AND THE LIKE Application filed February 5, 1930, Serial No.

My invention relates to improvements in soundboards for pianofortes and the like, and one of the objects of the improvements is to provide a soundboard in which the bridge or b bridges on which the strings are supported are constructed so that the sound is intensified and improved In instruments having crossing strings two bridges are provided, a long bridge curved in the manner of a harp for supporting the descantstrings, and a short one for supporting the crossing bass strings, and on the said bridges two pins are provided for each string, the said strings being deflected out of line by one of the pins and turn back into a direction parallel to the line of its main portion by the second pin.

In my improved soundboard the said bridges are divided along their median line thus producing two bridge bars running parallel to each other a small distance apart in lieu of a single one, and each bridge bar is provided with a series of pins so that each string bears on pins fixed to both bridge bars. While in constructions now in use in which both series of pins are fixed to an integral bridge the pressures exerted thereon from opposite sides are balanced within the bridge, in my improved construction the said pressures and the vibrations of the strings are transmitted to the soundboard. Another object of the improvements is to construct the bridge for supporting the bass strings so that the vibrations of the said bass strings are transmitted to a part of the soundboard capable of unimpeded vibration, and

with this object in view my invention con-' sists in supporting the bass bridge on a rockable lever bearing on a suitable portion of the soundboard and preferably below the bridge supporting the descant strings;

Thereby the pressures exerted by the descant and bass strings on the soundboard are compensated, so that the soundboard is relieved of the strain and is capable of following freely the acoustic vibrations of the strings.

For the purpose of explaining the invention an example embodying the same hasbeen shown in the accompanying drawing in which the same reference characters have been 426,128, and in Germany February 2, 1929.

larged scale taken on the line 2-2 of Fig. 3,

gig. 3 is a bottom view of the soundboard, an

Fig. 4 is a detail sectional View on an enlarged scale showing a part of the bridge supporting the descant strings.

In the example shown in the drawings two bridges are mounted on the soundboard e and each bridge is divided longitudinally into two bridge bars (P, d and b, b respectively, the said brid e bars being located parallel to each other an a small distance apart. The bridgebars d 03 are provided for supporting the descant strings, and the bridge bars b 6 supports the bass'strings. The first series of pins t as viewed from the side of the wrest plank is secured to the bridge bars I) and d and the second series of pins t is secured to the other bridge bars 6 and (P. The bridge bars can be reinforced relatively to each other by inserting suitable spacing members such as screws 1' between the same, the said spacing members preferably ending at points above the soundboard.

The pressures exerted by the strings on the pins 25 in opposite directions are transmittedythrough the bridge bars (1 d and b, b to the soundboard, so that also the acoustic vibrations of the strings are also transmitted to the said soundboard.

, The bridge 6 b supporting the bass strings is not supported directly on the soundboard, but on a plate p connected by means of pillars u with the ends of levers 0 rock ingly supported below the soundboard on brackets n, the pillars it being passed through holes made in the soundboard 0. At their Fig.

cant, strings 'lStliLIlSl'llltt6d1tQ a part of the soundboard which has. a .better'fvibration. i

pressure of the levers on the soundboard. Thus the pressure of the bass strings acts on the soundboard in a direction opposite to the direction of the pressure of the descant strings, so that the said pressures are co1npensated, and the soundboard is relieved of the strain caused by the said pressures. Therefore thesoundboard follows the acoustic vibrations of the strings more freely than in constructions in Which the soundboard is put undertension by t'he pressure of-the strings. I I,

Preferably the strings are"arranged so'that the deepest bass string is.connected yvith. that part of the soundboard the natural vibrations of which havexthe greatest amplitude. Tl'ierebytwo of the rocking-levers 0 cross each other in the manner shown in f When disposing thc'parts con the soundboard the room needed for the levers 0 must be taken into consideration. i

The highest descant strings are located on a part of the-soundboard which has comparatively unfavourable vibrations. In myiinproved soundboard the pressure of the-des- For this purpose the end of the ,descant bridge d (Z is connected bya rocking lever 0 with agportion of the soundboard having a better vibration, as is shown in Fig. For

this purpose the bottornsides of the bridge bars (Z and (l are recessedor flattened at their J,

ends, as'is shown in Fig. 4, so that the said end which the bridge supporting the bass strings is mounted, and rocking levers at the side of the soundboard opposite to the bridge, said rocking levers supporting said plate and bearing on the soundboard at a part remote from said plate.

5. In a pianoforte, a soundboard, bridges, one. engaged vbyflthe descant strings and the other en aged by the bass strings, a plate on Which the bridge supporting the bass strings -isinounted, and-rocking levers at the side of the soundboard opposite to said bridge, said rocking levers supporting said plate and bearing on the soundboard atvparts opposite tothe bridge supporting said desc ant strings.

6. In a pianoforte, a soundboard, a bridge supporting the bass strings, and a rocking lever supporting saidbridge at the part engaged-by the deepest string and bearing on a part of the. soundboard remote from said string and capable of vibration of amplitude.

In a pianoiortqa soundboard, a bridge mounted thereon, strings attached to said high bridge, and a rocking lever at the side of the soundboard opposite to said bridge, saidlever supporting said bridge atthe partengaging the highest string and, bearing on the soundboard at a part remote, froinsai'dbridge and I V capable of higher vibration,

In testimony whereof I aflix my signature.

RICHARD SANDER.

portions are out of contact with the soundboard, and the said-end portions areconnected V with a plate 1 or the like which is connected with the rocking lever 0 located below the 1 soundboard by means of a screwrh. The intensity of the sound can be vari'ed according to the position of the fulcrunis a rela- I tively to the length of the rocking levers 0.

I claim: I

1. In a pianoforte or the like, a soundboard, a bridge fixed thereto and comprising substantially parallel bars connected directly to v the soundboard and spaced from one another,

pins secured to said bars, and strings each .j

engaging one of thepins of each bar.

2. In a pianofortem- :the like, a sound board, abridge fixed theretoand comprising substantially parallel barszconnected directly to the soundboard and spaced from one an-.

other, means for spacing said 'barsfroin each other, pins secured to. said bars, and strings each engaging one of the-pinsvof each bar! 3. In a pianoforte, a soundboard, abridge, strings attached to said bridge, and rocking levers supporting said bridge and bearing on a portion ofthe soundboard remote from said bridge. v

4. In a pianoforte, a soundboard, bridges, one engaged by the descant strings and'the' other engaged by the bass strings, a'plate on

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