IMPROVEMENTS IN PIANO-FORTES
Year: 1885

page_text: "
I, WILLIAM PHILLIPS THOMPSON, Fel. Inst. P. A. of the Agency for Foreign
Patent Solicitors, 6, Lord Street, Liverpool, in the County of Lancaster, and
323 High Holborn, in the County of Middlesex, Civil Engineer, do hereby declare
the nature of the said invention for "IMPROVEMENTS IN PIANO-FORTES (A com-
munication from abroad by Paul Gmehlin of New York City, County and State in
the United States of America Inventor) and in what manner the same is to be
performed, to be particularly described and ascertained in and by the following
statement:—
In the drawing Figure 1 is a face view of the strings and bridges of a piano-
forte having the invention.
Figure 2 is a face view of the action of said instrument, looking in the direction
of the arrow that is represented in Figure 3.
Figure 3 is a cross-section of the instrument.
Figure 4 is a detail view of the damper.
Figure 5 a detail cross-section of the bar in which the extra damper rods are
swivelled.
Figure 6 is a top view of a portion of said bar.
The object of this invention is to increase the "singing quality" of a piano-forte
by means of certain additional strings, which are interposed between the system of
regular strings, but so located that they cannot be struck by the hammers, and
divided each into two equal parts, and also by means of certain connections
between the dampers whereby the damper which is one octave below the key
which is struck will be lifted off its strings.
Heretofore pianos have been constructed with strings interposed between the
regular strings, so as to vibrate by sympathy with the strings that are struck by
the hammers. Such interposed strings were of the same pitch as the strings near
which they were placed, and were intended to vibrate with the same note as the
strings that were actually struck by the hammers; or these strings were arranged
יד

page_text: to produce over tones or harmonics of the fundamental tone strings by having
the vibrating lengths of such strings made aliquot parts of the length of the
main strings.
The invention, so far as the first object is concerned, differs from the instru-
ments heretofore used in that the interposed string is divided into two equal
lengths, each half of which sounds by sympathy one octave higher than the main
strings near which it is placed.
As to the second object of the invention this is based upon the fact which has
been ascertained, that if a string in a piano, say the middle "C" is struck, and at
the same time the key "C" which is one octave below is depressed so as to set free
its damper but not give a sound, the effect will be that the strings pertaining
to the lower octave will sound so long as their key remains depressed in the
same pitch as the string which was actually struck. Hence, the invention, so far
as the second object is concerned, consists in uniting each damper with the damper
which is one octave below it, so as to lift it off the strings when itself lifted by
the depression of the key.
In the drawings with special reference to Figure 1 which shows the strings for
an upright piano-forte, although the invention is applicable to all piano-fortes, the
letter a represents the ordinary wrest plank string bridge, over which the ordinary
strings A run to the tuning pins b. d is the sounding-board bridge, over which
the strings A run, as is usual, to the hitch pins e, which are fixed in the iron plate B.
C is an additional sounding-board bridge, which is part of the invention, and
which runs midway between the wrest plank string bridge a and the sounding-
board bridge d. In this additional sounding-board bridge Care secured agraffes f.
DD are the additional strings of the invention. Each of these strings is secured
to a tuning pin b passed over the wrest plank bridge a, through an agraffe f, and
thence over the sounding-board bridge d to a hitch pin e. These additional
strings D D are indicated by dotted lines in Figures 1 and 3, Figure 3 showing
also the arrangement of the bridge a in the wrest plank, and of the bridge C
on the sounding-board E. Figure 3 also shows that each string D is placed back
of the plane in which the regular strings A A are located, so that the strings D
cannot be struck by the hammers F of the piano. It will be seen that the agraffes f
divide the additional strings DD into halves of equal length, that is the two
halves of each string are equal in length. In tuning, these additional strings are
tuned one octave higher than the regular strings next to them, and being divided
into equal halves each of these additional strings will sound as two strings an
octave higher than the strings near them which are struck. By this arrangement
each note or cord of three regular strings will, when struck by the hammer, cause
the two halves of the additional string D to vibrate by sympathy an octave higher
than the note which is struck by the hammer, thus producing a rich and full sound
far superior to that produced if an additional string having the same pitch is placed
so as to sound by sympathy near the regular strings.
An additional advantage which is obtained from the use of these strings D D is
that, engaging by means of the agraffes f with the centre of the sounding-board,
they serve to brace the sounding-board, giving it additional upward strain. The
dampers for these additional strings are shown at tt in Figures 1 and 3, they being
affixed to slides uu, that can be moved by a pedal. A spring holds these
dampers on the strings D normally, but whenever the singing quality of the
instrument is wanted, a depression of the pedal causes all the dampers t to be
moved off the strings D, leaving the latter free to vibrate.
The main strings A may be continued beyond the bridge a to a further bridge
on the sounding-board, so as to produce extensions between these two bridges that
will be aliquot parts of the length of the main strings and vibrate in sympathy
therewith.
I will now describe the second part of the improvement, which seeks to make
the strings in an octave below sound, whenever a key is struck.

page_text: Figure 3 shows at G an ordinary damper, which is lifted off a string whenever
the key H is depressed and before the hammer F strikes the strings. g is the
damper lever, the damper wire upon which the damper head G is secured. All
these are as commonly employed in actions of upright pianos, and are not of the
invention. In Figure 2 is shown an inner face view of two octaves of dampers,
that is to say, looking at the striking faces of the dampers. From this Figure it
will very clearly appear how this object is carried into effect, namely: To the
ordinary damper wire of each damper is affixed a small block i, which has an
eye at its outer or back part. Through this eye is inserted one end of a long wire
or lever I, the other end of which is swivelled in a rail J which is stationarily
supported by a bracket or brackets on the immovable portions of the instrument.
Each damper lever g carries on its back a small cushion or projection m.
A careful examination of Figure 2 will show that the cushion m, which is in
contact with a lever I belongs to that damper which is an octave below the damper
to which such lever is attached. Confusion will be avoided if it be remembered
that Figure 2 being a back view, shows the lower keys at the right hand side.
Thus, taking the extreme left damper of Figure 2, which is marked as belonging to
the key "C" its lever I is in contact with the cushion m of the damper belonging
to the key "C" that is one octave below that first named. Therefore, if the
damper first named that is, the one on the extreme left in Figure 2, be moved away
from the string, which would be away from the observer of Figure 2, it will carry
the lever I with it, and this lever I by this motion will, pressing the cushion m of
the damper which is an octave lower, cause said damper to leave contact with
its strings, thus setting them free to sound in harmony with the strings that
are struck an octave above them, and, as already stated, this sound will be in
the pitch of the octave above and not in the pitch which would be produced were
the strings of the lower octave struck by their hammer.
The rail J, which receives the wire levers II, has by preference bushed holes, in
which the said levers are swivelled and is secured across the whole length of the
damper levers, so as not to interfere with the raising of all the dampers by pedal
action.
Although I have described the levers I as the instrumentalities by which each
damper connects with the damper that is one octave below it, I desire to state that
I do not wish to limit myself to that particular style or kind of connection, as the
invention can be carried into effect by other means which would permit the lifting
of the dampers in the manner described.
As regards the additional strings D heretofore referred to, I wish to state also
that it is not essential that they should run parallel with the main strings A, or
that there should be one such additional string for every set of two or three main
strings A, as their direction or number may be varied ad libitum.
Having now particularly described and ascertained the nature of the said
invention and in what manner the same is to be performed I declare that what
I claim is
1. In a piano-forte the combination of the regular strings A A and their
sustaining bridges a, d with the agraffes f on the sounding-board and additional
strings DD, which by said agraffes are divided into equal vibratory halves, and
adapted to sound by sympathy when the regular strings are struck, as specified.
2. The combination of the sounding-board E with the middle bridge C, agraffes f,
extra strings D, wrest plank string bridge a, sounding-board bridge d, and main
strings A A, substantially as and for the purposes specified.
3. The extra strings D, combined with the dampers tt on the slides u u substan-
tially as herein shown and described.
4. In a piano-forte the dampers G, united in pairs at the ends of each octave
substantially as described, so that the upper damper of the octave will lift the
lower, as specified.

page_text: 5. The combination of the dampers G G with the blocks ii, levers II, rail J,
and cushions m, as described.
6. The damper G, having block i and cushion m, substantially as and for the
purpose specified.
7. In a piano-forte the combination of the main strings A. A with the additional
strings D D agraffes f, interposed sounding-board bridge C dampers G and con-
necting devices I between said dampers, all as specified.