Improvements in Pianofortes.
Year: 1893

page_text: Date of Application, 22nd June, 1893-Accepted, 22nd July, 1893
F
Improvements in Pianofortes.
A communication by HEINRICH KAIM, of Kirchheim under Teck, in the Empire
of Germany, Pianoforte Manufacturer.
I, WILLIAM PHILLIPS THOMPSON F.C.S. M.I.M.E., of the Agency for
Foreign Patent Solicitors 6 Lord Street, Liverpool and 6, Bank Street,
Manchester, both in the County of Lancaster and 323 High Holborn, in the
County of Middlesex, Civil Engineer, do hereby declare the nature of this invention
and in what manner the same is to be performed, to be particularly described and
ascertained in and by the following statement :-
This invention has for its object to vary the distances in all pianofortes when at
rest between the hammers and the wires, in order to produce a heavier or lighter
blow of the hammers whilst the position and descent of the keys remain unaltered,
and also to render it possible that, with one and the same mechanism, the playing
may at any moment as desired be made louder or softer, and also that the adjustment
of the keys is not done as hitherto by the insertion of small plates on their axes,
but, by means of an arrangement on the ends of the keys or on the lever, which
will be hereinafter more particularly described.
These improvements are shown on the accompanying drawings in Figures 1 to 3
for grand pianos, and Figure 4 for cottage or upright pianos.
The levelling of the keys T on their contact side, without the insertion of small
plates on their axis, is brought about by cutting a slot at the other end of the key,
whereby the latter is divided into two tongues T¹ and T' of unequal thickness,
which are connected with one another by means of a right and left hand threaded
set screw in such a way that they may be drawn to or separated from each other
owing to the lower thin tongue T² having a springy action. According as this
bending is a greater or less one, the key T will descend more or less at its rear
side until it rests on its felt bed, whilst the front of the key will be correspondingly
raised. By means of the set screw t, all the keys may thus be easily adjusted and
levelled. In order not to weaken the keys, the tongue T¹ may be replaced by a
spring secured beneath the key.
In order that the distance of the hammers from the wires, when in a state of
quiescence, may be varied, the arrangements shown in Figures 1, 2 and 3 are used
for grand pianos; in common with those for cottage or upright pianos, they are
based essentially on the arrangement of inclined surfaces attached to the mechanism,
or the keys, or on both, against which surfaces adjustable stops are pressed which
transfer the pressure from the keys to the mechanism, and, according to their
adjustment on the inclined surfaces, vary the distances between the hammers and
the wires, before the keys are struck.
In the upright piano action shown in Figure 4, the key T acts by means of the
link Jon a contact surface D' pivoted to the lever G of the mechanism, instead of
directly on such lever, this contact surface being capable of adjustment by means
of the set screw d'. The rest bar H of the hammers A¹ is connected, by means of
the arms n and k, and the connecting rod M, with the bar K which operates the
common movement forward of the various push bars J, and this bar K is again
connected by means of the arms with each separate push bar J. The spring f
which presses on the arm k, causes the rest bar H, when no pressure is exercised
thereon, to return, together with the strip or bar K and push bars J, to its normal
position.
If the hammers are to be moved nearer the wires, in order (for instance) to assume
the position shown in dotted lines in Figure 1. the hammer bar H. Figure 4. is

page_text: turned in the usual manner by means of the soft pedal, so that the push bars J are
pressed more to the right, and the levers G are raised by means of the inclined
contacts D', that is to say, the push tongues g always remain under the hammer
shafts, and the least pressure on the keys suffices to cause the hammers to strike
(because no contracted air pressure is formed).
In order to allow of each separate push bar J being regulated, it is pivoted to a
spring arm J, which is arranged on the rear of the key, said arm being adjustable
by means of a small set screw i¹.
In order to enable the push bars J to be adjusted horizontally, the rod M,
which forms the connection between H and K has nuts m m, which bear on the
arms n and k.
The arrangements for moving the hammers nearer the wires in the case of grand
pianos are shown in Figures 1-3, and are based on the same principle as those of
cottage (or upright) pianos.
In Figure 2, the adjustable lever e³, which has two heel pieces, is arranged by
means of the guide link p² and the guide strip E³, on the contact knob C of the rear
of the key, in such a way that either the front or rear projection of e³ rests thereon,
and the hammers can, consequently, be regulated to a given distance from the
wires.
In Figure 3, the movable lever e³ is arranged on the mechanism and adjusted by
means of the guide link p¹ of the guide strip E', presses against the inclined surface
of the tumbler Carranged on the rear end of the key, and, by adjustment on the
same, the hammers may be approached to, or removed from, the. wires as may be
desired. The tumbler C₁ is made vertically adjustable by means of the set screw c'.
Another arrangement is shown in Figure 1. In this, a so-called stop ball e is
pushed, by means of the guide strip E and small bar p, between two converging
surfaces. One of these surfaces is made adjustable, as regards its inclination on
the lower part of the arm B of the mechanism, by means of the contact D and set
screw d, the other inclined surface is fixed on the tumbler C and vertically
adjustable by means of the set screw c on the rear end of the key. By means
of this arrangement, the hammers A may be also adjusted as regards the
distance from the wires S, even during playing, whilst, as in all the aforementioned
devices, the movement of the keys remains equal in any position of the hammers,
but the tone may be made softer or louder, as one of the two inclined surfaces
of C or D passes behind the normal point of contact of the stop ball c parallel
with the other inclined surface, see Figure 1, whereby, on a further backward
movement of the stop ball away from the normal point of contact, the hammers
retain their normal position unchanged, but the tone becomes always louder, as
the point of contact for lifting the mechanism and hammer is more and more
removed from the axis of the key T. It is thus possible, by means of one
and the same mechanism through the moving of the stop ball to a given position,
to make the tone, at any moment as desired, louder or softer without further
trouble, or, after passing the same, to cause the hammers to approach more or less
towards the wires.
C
A still greater softening of the sound (pianissimo) may be obtained with the
same action by stopping one wire of each group of strings (3 or 2 stringed) and
thus not allowing it to sound. Figure 1 shows a method of doing this in which
a stop u is pressed between two groups of strings thus preventing one string of
each group from sounding. The stops u are fixed on a common pivoted arm U,
and are operated by the bars and v¹. The bar is rigidly connected with the
strip E or its parts, and makes an angular movement therewith. As soon as the
pedal is touched, the stops u are caused to approach the wires, but only reach
the same if the pedal be depressed more than half way. The stops u may, of
course, be operated in any other suitable manner to that hereinbefore described.
The aforementioned arrangements avoid the unequal wearing away of the
hammers, which, in the pianoforte actions hitherto employed for shifting the blow
to 2 wires, have acted deleteriously upon the instrument.
from

page_text: The softening of tone is, further, an even one, whilst no alteration is produced in
the shifting piano action, especially in the lower bass clefs.
Having now particularly described and ascertained the nature of the said inven-
tion, and in what manner the same is to be performed, as communicated to me
by my foreign correspondent, I declare that what I claim is :-
1. An improved device for adjusting the height of the keys of pianofortes,
characterised by the rear of the keys being either divided, in which case the lower
tongue T is made so thin that it can be more or less curved by means of a set
screw at its free end, or a special spring plate may be attached to the rear of the
key, the free end of which plate may be adjustable by means of a set screw,
substantially as described.
2. In pianofortes, the arrangement of inclined surfaces, or projections such as
shown in Figure 2, on which an arm or stop ball is pushed, whereby the mechanism,
together with the hammers, is gradually moved nearer the wires without altering
the position or movement of the keys, substantially as and for the purposes
described.
3. In an arrangement such as described in Claim 2, having one of the inclined
surfaces from a given point parallel with the other, whereby, whilst the tone is
altered, the position of the hammers remains unaltered as soon as the ball has
reached a given point, substantially as described.
4. The device such as described, and illustrated in Figure 1, whereby one string
of each two chords (two or three stringed) is deadened, by means of a stop u
connected with the bar E and operated therewith by means of a pedal when the
latter is depressed about half way.
Dated this 21st day of June 1893.
WM. P. THOMPSON & Co.,
Agents for the Applicant.