IMPROVEMENTS IN THE SOUNDING BOARDS OF PIANOS AND THE BODIES OF STRINGED INSTRUMENTS
Year: 1884

page_text: I KARL WILHELM LANGLOTZ Bookbinder in Nordhausen (Germany) do hereby
declare the nature of my said Invention for IMPROVEMENTS IN THE SOUNDING
BOARDS OF PIANOS AND THE BODIES OF STRINGED INSTRUMENTS and in what
manner the same is to be performed, to be particularly described and ascertained
in and by the following statement :—
Red-pine has been almost exclusively used hitherto for the sounding boards of
pianos and for the bodies of stringed instruments such as violins or violoncellos or
the like and though the very best and most regular wood is sought out for this
purpose yet it cannot be found perfectly homogeneous and in consequence of the
alternate hard and soft places therein a varying resistance to the vibration of the
sounding board or body made therefrom is produced especially in a transverse
direction and the tone produced by the vibrations of the chords suffers thereby
both as regards clearness and fulness of sound. Wood also owing to the varying
quality of its layers is extremely sensitive to purely outside influences such as
changes in the temperature and moisture of the air and the like and these changes
affect the wood in a very unequal measure. The resonant qualities of a wooden
sounding board or body as aforesaid are therefore by no means uniform.
Now the object of this my Invention is the removal of these deficiencies and
drawbacks by making a perfectly homogeneous material and using this material for
the formation of sounding boards for pianos and bodies of stringed instruments.
According to one method I make a number of thin sheets of paper from a
uniform wood fibre or straw pulp and each sheet is uniformly sprinkled with
pulverized resin or other analogous substance or painted over with a strong
solution of glue or other adhesive material and when thoroughly dry a sufficient
number of these sheets are laid on each other and subjected to a heavy pressure in
a warmed or heated press. By this method a very close and intimate connection
of the single sheets is attained and an article of considerable elasticity and of great
homogeneity in all directions is produced.
According to another method the wood fibre or straw pulp can be mixed with
pulverized resin or other analogous substance or with glue or other similar material
and pressed in a mould or otherwise between hot plates or in a heated state into
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page_text: slabs of the required dimensions and then thoroughly dried and an homogeneous
slab is thus produced.
The volume of the binding material to be used in making these slabs must be
equal or thereabouts to the volume of the wood fibre or straw stuff. In order to
protect those slabs against moisture which have been made by the wet process
herein before described that is to say where glue or other adhesive material has
been used it is very convenient to varnish the outer surfaces of the said slabs or to
treat the same with double chromic acid alkali. When resin has been used or
other analogous substance in the manufacture of these slabs this treatment as
aforesaid will not be required.
This resonance material made as aforesaid is almost perfectly indifferent to
changes of temperature as the substances of which it is composed are extremely
bad conductors of heat. When the slabs so formed are made to vibrate all parts of
the said slabs do so vibrate perfectly uniformly for the resistance in all the
oscillation planes is the same over the whole of the slab. This material is also
advantageous and useful inasmuch as it cannot crack and also is easily shaped
while it can be made of any desired dimensions not only in superficial area but also
in thickness.
Having now particularly described and ascertained the nature of my said
Invention and in what manner the saine is to be performed I declare that what
I claim is
1. The sounding boards of pianos and the bodies of stringed instruments made
of a number of thin sheets of paper formed from wood fibre or straw pulp joined
together by a binding material and pressed into slabs substantially as and for the
purpose herein before described and set forth.
2. The sounding boards of pianos and the bodies of stringed instruments made
from wood fibre or straw pulp mixed with a binding material and pressed into
slabs substantially as and for the purpose hereinbefore described and set forth.
3. The method of manufacturing the material for use in the formation of the
sounding boards of pianos and the bodies of stringed instruments substantially as
herein before described.
Doted this 5th day of Cantonbon 1001.