Year: 1886

page_text: Date of Application, 10th Apr., 1886
Complete Left, 10th Jan., 1887.
Complete Accepted, 22nd Mar., 1887.
I HERMANN BILLETER of Schaffhausen, Switzerland, Teacher of Music, do hereby
declare the nature of this invention to be as follows
The object of this invention is to avoid the annoyance of piano playing. For this
purpose different appliances has been introduced-on pianos, but they were either too
expensive, or too complicated, or only applicable to certain instruments.
The present arrangement is designed either to snother the tune of the instrument
or to permit silent playing. It can easily be applied to upright and grand pianos.
A cross piece placed as closely as possible below the hammers has before each
hammer-shaft a small sloped hammer guided by a pin. The cross piece is suspended
by means of supports on pins which are fastened to the inside of the piano casing the
cross piece being constantly impelled to one side by a spring. The supports are
subjected to the action of the other springs which keep the cross piece at a certain
distance from the strings on the other hand these supports are connected by truss
rods to levers which can be moved forward or backwards by the action of a curved
dise on a roller. By this means the cross piece can be brought into such positions,
that the hammers do not touch the strings, but act upon the heads of the small hammers
with their shafts so as to make them touch the strings with their soft surfaces; or the
action of these can also be interrupted, and the action of the hammers completely
paralized by india rubber stops or buffers. In the first case the sound would be
softened in the last case completely stopped; this last effect will however only be
obtained by a lateral displacement of the cross piece in consequence of which the
heads will no longer be in opposite positions to the shafts which is also obtained by
the curved disc the nose of which acts on suitable levers. These transmit their
lateral motion by rods to the supports and cross-piece surmounting the resistance of
the spring. By this means in continuing to turn the disc the mechanism will be
thrown out of gear when the hammers have to strike the strings. The levers pivot on

page_text: pins which are fastened in the front plate of the piano-casing while the one set of
levers can oscillate on pivots and at the same time have to follow the lateral motion of
the other set of levers the head being for this purpose so arranged as to turn on its
fulerum in the front part of the mechanism. A knob placed at the outside of the
piano casing serves to give the desired position to the disc.
The intensity of tone produced by the striking of the sloped hammers depends upon
the softness of the felt which covers the surface of contact and can therefore be
regulated at will. The sloped hammers are thrown back by the action of spiral
springs as soon as the principal hammers are falling back.
The foregoing will serve to illustrate the general construction of this mechanism in
which however considerable modification can be made without departing from the
spirit of the invention.

page_text: COMPLETE SPECIFICATION.
Improvements in Damper Mechanism for Pianofortes.
I, HERMANN BILLETER of Schaffhausen, Switzerland, Teacher of Music, do hereby
declare the nature of this invention to be particularly described and ascertained in
and by the following statement :—
The object of this invention is to avoid the annoyance of piano playing practice.
For this purpose different appliances have been introduced on pianos but they have
been either too expensive or too complicated or only appliable to certain instruments.
The present arrangement as shown by the annexed drawing in figures 1 to 4 is
designed either to smother the tune of the instrument or to permit silent playing. It
can easily be applied to upright and grand pianos.
Through a cross piece B figure 2 placed as closely as possible below the hammers A
and at the same distance apart passes a row of small soft faced hammers E guided
by pins D and having soft heads H. The cross-piece B is suspended by means of the
supports K on the pins J which are fastened to the inside of the piano casing the
cross piece B being constantly impelled to one side by a spring L. The supports K
are also subjected to the action of other springs M figure 1 which impel the cross
piece B away from the strings. The supports K are also connected by the tie rods N
to levers P figure 1 which can be moved forwards or backwards by the action of a
cam disc S on the roller R. Below the small hammers E is a buffer or cushion T
made of india-rubber or other suitable material extending the whole length of the
bar B. In addition to having an oscillatory motion on the pins J the supports Kare
capable of a lateral motion thereon. This is produced by means of a nose or
projections formed on the periphery of the cam disc S acting on levers U which are
pivotted at to the inside of the front plate of the instrument. The levers U are
connected by means of rods V to the bar B or to the supports K of the same.
turning the knob X of the cam dise S until the projections on the latter engages with
one of the levers U or with a rod connecting the same a lateral motion will be
imparted thereto and also to the rods V and to the supports K of the bar B. To
admit of this lateral motion the blocks W which carry the fulcrum pins d of the
levers are themselves pivotted to the framework so as to allow the levers P to
follow the motion of the levers U.
By
The normal disposition of the parts of the instrument above described may be
assumed to be that in which the hammers A would strike the strings and produce
full tone. In this state the cam S would be turned until the summit thereof was in
contact with the roller R when the bar B would be forced nearer to the strings than
is shown in figure 1. The lateral position of the bar B would be that shown in figure 2
the small hammers E standing midway between the shafts a of the hammers A there
is therefor nothing to interfere with the free action of the latter. To produce a
softened tone the cam § must be adjusted as shown in figure 1 where the roller R
rests on the flat portion of the cam S permitting the springs M to force the bar B
away from the strings. The cam must be turned until the projections has imparted

page_text: the lateral motion above described to the bar B and placed the heads H of the
hammers E opposite the shafts a of the hammers A which latter when played upon
force the hammers E against the strings and produce a subdued tone the forward
motion of the hammer A being arrested as soon as the hammer E touches the string.
After impact the hammers E are returned to their normal position by the spiral
springs Fencircling the pins or stems D.
It will be observed that the shape of the cam S admits of its being turned round a
considerable portion of a revolution without altering the position of the bar B. In
order to permit dumb playing or the suppression of all sound from the strings the
cam S is turned until the projections ceases to bear on the levers U and the spring L
has caused the bar to resume the position shown in figure 2 in which the hammers E
cannot be acted on by the hammer shafts a and the latter therefore strike against and
are arrested before reaching the strings by the buffer or cushion T.
The intensity of tone produced by the striking of the hammers E depends upon the
softness of the felt which covers the surface of contact and can therefore be
regulated at will.
The foregoing will serve to illustrate the general construction of this mechanism in
which however considerable modification can be made without departing from the
spirit of the invention.
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 the application of mechanism such as the oscillating cross piece B
having also a lateral motion and carrying soft hammers E which may be interposed
between the strings and the hammers A. substantially as and for the purpose specified.
2. The combination with damping mechanism consisting of apparatus such as the
cross piece Band hammers E of stops or buffers T for the purpose of reducing the
impact of the shafts a against the cross piece B substantially as specified.
3. The combination in damping mechanism of a movable cross piece B disc $
provided with nose s levers P and U supports K and rods N and V operating in
imanner substantially as specified.
Dated this 10th day of January 1887 ·