IMPROVEMENTS IN PIANOFORTES
Year: 1885

page_text: I, EMIL HÖFINGHOFF of Barmen Rhenish Prussia, German Empire, Merchant
do hereby declare the nature of my invention for IMPROVEMENTS IN PIANOFORTES
to be as follows:-
1.) By these improvements the power of the tone or sound of a pianoforte (grand
piano) can be diminished to a minimum at the will of the player.
2.) The tone will be improved in quality.
3.) The piano & especially the sound board will be guarded against the ruinous
influences of temperature and dampness and consequently an instrument provided
with my improvements will have a sound of good quality much longer than
without them.
My invention consists in the construction & the use of a "damper cover" B
which is fastened to the back of the piano or to the bottom of the grand piano.
This cover is hinged to the instrument by the hinges C so that it can be opened
or closed conveniently and it is held tight by the cramps or. hooks D and
corresponding eyes.
The cover B is provided at the inner side, that is at the side facing the sound
board, with wooden boxes or dampers A which take up the spaces between the
frame E of the instrument at the back side of the piano or at the bottom of the
grand piano when the cover is closed or nearly so.
These boxes are filled out with cotton waste from the spinning mills or other
suitable material which is a bad conductor of sound or having the quality of
damping the same.
The side of the boxes facing the sound board F is covered with a coarse or
woolly stuff. When the damper cover is closed the coarse woolly stuff on the boxes
bears against the sound board F so damping the sound of the same.
If it is desired that the tone shall be damped less, a little space is left between
the damper boxes and the sound board.
The tone of the instrument diminished by this means sounds softer & sweeter
than the original piano tone which can be obtained in its full power if the cover B
with the damper boxes A is opened.
The manner used until now in closing the back of the pianofortes by a light
frame containing a pannel of wire gauze or of other light woven stuff has the great
Festa 2771

page_text: disadvantage that dampness and other influences of temperature are in no way
hindered to have a detrimental effect to the sound board and so gradually ruin its
resounding quality and its vibratory power.
The inner mechanismes also, the strings etc. suffer by the dampness entering the
instrument by the open back. This is obviated by the damper cover described
which locks up the sound board air-tight, and an instrument can be kept in use
much longer than before.
I claim as my invention:
1.) "The use of " sound dampers" at the back or at the bottom of a pianoforte
or a grand piano respectively which act upon the sound board."
2.) "The use of "sound dampers" at the back or at the bottom of a pianoforte
or a grand piano respectively, taking up the spaces between the frame or skeleton
beams of the instrument at its back or bottom sides respectively."

page_text: mрrоvешеных ш гадогогтев.
I, EMIL HÖFINGHOFF of Barmen in the Province of Rhenish Prussia, German
Empire, Merchant do hereby declare the nature of my invention for IMPROVEMENTS
IN PIANOFORTES and in what manner the same is to be performed, to be particularly
described and ascertained in and by the following statement:-
1.) By these improvements the power of the tone or sound of a pianoforte or a
grand piano can be diminished to a minimum or developed to a full fortissimo at
the will of the player.
2.) The tone will be improved.
3.) The piano and especially the sounding board is guarded against the ruinous
influences of temperature and dampness and consequently an instrument provided
with my improvements will have a sound of good quality much longer than
without them.
These objects are attained by the arrangements illustrated in the accompanying
drawings in which:
Fig. 1. is a vertical section of a piano showing my invention arranged as a
damper cover which can be opened or closed by pressing down a pedal, or by hand.
Fig. 2. is a horizontal section of the same, the right hand side-when looking
from the back-showing the cover held tight by a hook or cramp, if the opening or
closing is done by hand as described in the provisional specification. The other
part of the figure shows the mechanical arrangement for opening & closing the
cover and the same provided with a counterweight.
Fig. 3. is a vertical section of a piano showing my invention as arranged when
used as a "crescendo or decrescendo cover or apparatus" with the mechanisme for
opening the same by the use of a pedal.
Fig. 4 shows a back view, partly in section showing at the left side the counter
weight & at the right side the fastening hook & eye when the cover is locked
by hand.
My invention consists in the use of a special cover B at the back of a piano (with
a "grand piano " the cover would have to be fixed to the bottom of the
instrument) which is fastened to it by hinges C so that it can be opened or closed
conveniently.
The opening or closing can be done by hand or by preference by using a special
pedal which when being pressed down or raised opens or closes the cover as will be
seen hereafter.
"
If the opening of the cover is done by hand it is held tight, when closed, by
hooks D (fig. 2). If the cover is intended to serve as a damper cover" it is
provided at the inner side, that is the side facing the sounding board, with wood
boxes or dampers A which take up the spaces between the frame E of the
instrument at the back side of the piano or at the bottom of the grand piano when
the cover is closed.
These boxes are filled out with cotton waste or other suitable material which is
a bad conductor of sound or which has the quality of damping the sound.
The side of the boxes facing the board F may be covered with a coars woolly
stuff. When the damper cover is closed it is best to have a little space between the
boxes and the sounding board.

page_text: The tone of an instrument diminished by this means sounds softer, more sonorous
than the original piano tone which can be obtained in its full power when the
cover B with the damper boxes is opened. If the damper cover is principally
intended to serve as " crescendo & decrescendo apparatus" it is constructed as shown
by fig. 3, forming simply a close cover G without damper boxes, but shutting up
the back of the piano-or the bottom of a grand piano-when closed quite tight
and which may be opened at pleasure by the same mechanical arrangement as used
for the "damper cover" and described hereafter. This cover may be lagged with
stuff in order to close tighter & to give the tone more softness.
The device used until now for closing the back of a piano consists of a light
frame containing a pannel of wire gauze or other light woven stuff and has the
great disadvantage that dampness and other influences of temperature are in no
way hindered to have a destructive effect on the sounding board and so gradually
ruin its resounding quality or its vibratory power.
The inner mechanisine also, the strings etc. suffer by the dampness entering the
instrument by the open back.
This is obviated by the "damper cover" and by the "crescendo & decrescendo
apparatus" described which lock up the sound board air tight and the instrument
can therefore be kept in use much longer, if provided with these.
In order to enable the player to open or close the cover at will, I provide the
piano with a pedal H, arranged at the side or between the usual pedals and at the
back of the cover (B or G) I fix a bar or lever I of suitable length and I connect
the two as shown by figures 1 & 3, by a cord, string or chain O, fastened below at
the end of the bar I and passing over the grooved pullics L, M, N of which the two
first ones are fixed at the bottom of the instrument & the third at its inside and in
such a manner that (that) the cord or string can pass freely without causing friction
anywhere & reach the pedal in the desired manner.
A glance at the figures 1 & 3 will show then that by pressing the pedal down
more or less the cover will be opened correspondingly.
In order to keep the string O always tight it is provided at its outer end with a
double loop, nut R with right & left band thread, into which the screws S, S¹ fit
& to these the cord is fastened.
The cover is further provided with counterweights T for balancing the weight
of the same.
These counterweights may be arranged one each at the sides of the
instrument or only one in the middle of the cover may be used.
The weights are suspended on strings U passing over a pulley V conveniently
fixed at the frame of the instrument.
Having now particularly described and ascertained the manner of my said
invention and in what manner the same is to be performed, I declare that what
1 claim is:
1.) A cover A (fig. 1) with damper boxes-(damper cover).
"2.) A cover G (fig. 3) without damper boxes-(crescendo & decrescendo
apparatus) both fixed at the back of a piano-(instead of the ordinary cover with
wire gauze or thin woven stuff, the object of which is to let the tone always pass
through in its full power)—and being so constructed that they may be opened and
closed at the will of the player by hand or by a mechanical arrangement."
Dated this 26th day of Fohrnaz 1886
KARL I. MAYER,
Agent for Mr. E. Höfinghoff.