improvements in sounding Boards.
Year: 1898

page_text: Date of Application, 5th Mar., 1898-Accepted, 16th Apr., 1898
improvements in sounding Boards.
I, REGINALD HADDAN, of the Firm of Herbert Haddan & Co., of 18, Buckingham
Street, Strand, London, W.C., Patent Agent, do hereby declare the nature of this
invention a communication to me from abroad by Constantin Schmidtlein, of 22,
Luisenstrasse, Berlin, Germany, Engineer, and in what manner the same is to be
performed to be particularly described and ascertained in and by the following
statement :-
This invention relates to sounding boards and consists in making them in such a
way that they are thicker at the centre or at or along some more or less central
line and from there taper gradually up to the edges where the board is mounted on
its support preferably with an increasing amount of taper or reduction in proportion
as the distance from the centre or more or less central line increases.
Such a sounding board tapering gradually and smoothly is thus more or less
lens like or lenticular and may be curved on both faces, or have the one or the
other face plane.
The exterior edges are preferably of equal thickness around the circumference of
the sounding board, consequently the contours or lines of various given thickness
will lie more or less parallel to the exterior edges. The tapering of the sounding
board is continued evenly and progressively up to its support or surrounding frame
but the part that lies directly upon such support or frame may be plane if desired
and not tapered.
Such sounding boards are preferably made of two or more thicknesses of wood
fastened together so that the grain of the wood of one or each thickness crosses the
grain of the other or next thickness.
As an example of the thickness of such sounding boards, those for pianofortes
may be from 15 to 50 millimeters or more thick at the thickest part and taper to
from 4 to 15 millimeters or more at the thinnest part.
For other instruments the sizes would be increased or diminished proportionally
to the relative size of the instrument.
Where such sounding boards are used in the construction of violins, and stringed
instruments of that class, it is preferred to have the outer face curved and the
inner face plane.
In the annexed drawing Fig. 1 is a front view of a sounding board for upright
pianofortes. Figs. 2 and 3 are cross sections thereof. Fig. 4 is a plan view of a
sounding board for horizontal pianofortes. Figs. 5 and 6 are cross sections thereof.
Fig. 7 is a cross sectional view on a larger scale illustrating the construction of the
sounding board.
The numbers on the figures represent suitable thicknesses in millimeters and the
dotted lines represent contours where the thickness is equal. A represents the
sounding board, B the bridge and C the support of the sounding board.
In Fig. 7 A represents one layer and A2 another layer where the sound board is
constructed of two layers.

page_text: Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed I declare that what I
claim is :-
1. A sounding board thicker at or about the middle and tapered up to its
support so as to be lenticular in section with both sides curved or one side curved
and the other side plane substantially as set forth.
2. A sounding board composed of superposed boards or plates of wood with the
grain crossing one another such sounding board being thicker at or about the
middle and tapered up to its support so as to be lenticular in section with both
sides curved or one side curved and the other side plane substantially as set forth.
Dated this 4th day of March 1898
R. HADDAN.