Year: 1888

page_text: I JACOB WILHELM ERBE Manufacturer of Musical Instruments of Eisenach in the
Great Duchy of Saxony-Weimar-Eisenach in the German Empire 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 :-
The hereinafter described invention has reference to a piano combined with a
harmonium by means of which the piano alone or the harmonium or both may be
played together by using one key board only and whereby the same uniform pressure
is required to move the keys whether the harmonium or the piano or the two together
are being played. This invention is illustrated in the accompanying drawings in
which Figure 1 is a longitudinal section of the combined piano and harmonium on the
section line CD of Figure 2. Figure 2 is a cross section on section line A B of
Figure 1. Figure 3 is partly a section on line E F and a section on line G H of
Figure 2.
Figure 4 is a longitudinal section of the piano showing a front view of the
centrivance for displacing the decrescendo mechanism or leverage of the piano.
Figure 5 is a view partly in section of the floor or bottom of the key board showing
also a side view of the decrescendo mechanism or leverage for reducing the compass
or extent of the sound of the piano or for entirely displacing the mechanism of
the piano.
Figure 6 shows a horizontal section partly through the air chamber at GH
(Figure 2) and partly through the wind chest F (Figures 1 and 2). Figure 7 shows
in cross section the folding or movable and adjustable contrivance for the decrescendo
mechanism or leverage. Figure 8 is a plan of Figure 7. Figure 9 shows a cross
section of the mechanism of the register. Figure 10 is a front view of this register
mechanism the wind chest being cut through.
Figure 11 shows in section the arrangement of the register mechanism in the
register producing "expressive" and "loud play."
The combined piano and harmonium forms the union of the well known instrument
called a harmonium with a piano in such a manner that the same key board in
combination with suitable register mechanism serves either to play the piano alone
or to play the harmonium and the piano together lastly to play the harmonium
alone the height or extent of sound of the instrument being increased or muffled or
diminished by the arrangement of a crescendo and decrescendo mechanism or the

page_text: piano being entirely thrown out of action. The harmonium can be further altered or
modified in sound by different register mechanism (Bassoon English horn, flute,
clarionet and such like). A characteristic feature of this combined piano and
harmonium is that the keys can be constantly easily and uniformly played (being
a matter of absolute indifference) whether the harmonium or the piano or both are
played at the same time and that in order to include or dispense with the harmonium
nothing more is needed than to actuate the hellows or to release them. In a similar
manner the motion of the decrescendo mechanism suffices to exclude or dispense with
the use of the mechanism of the piano.
The mechanism of the piano may be of any desired construction with the exception
of the keys which differ from the ordinary construction in as much as they are
lengthened at the rear and carry at their rear and lower sides valves by means of
which is ordinarily covered or muffled the wind channels or passages of the reed or
sound boxes of harmoniums and thereby the reeds being left free to vibrate when the
said keys are raised.
The harmonium is arranged in the following manner :-The bellows H for the wind
are arranged in the front part of the case or chest of the piano and are moved up and
down by the treadle a with the intermediary of the lever a having two arms and of the
connecting rods a¹. The wind taken up by the bellows in their up and down motion
is driven through the vertical passages or channels and through the lateral
passages into the collecting bellows G which are formed upon a flooring G¹
suspended at its four sides to the floor G3 of the wind chest by means of leather
folds or bags G. By means of springs L which are arranged between the flooring G
and the top or part H¹ of the bellows H the collecting bellows G are maintained
constantly pressed together while the wind supplied by the bellows H serves to
expand the same. By this arrangement a proportionately constant pressure of air is
obtained in the collecting bellows G. Above these latter bellows G is placed the
wind chest F which is divided in two separate halves by a partition or division wall F¹
into which halves the air flows through two openings c¹ c¹ controlled by the valves cc.
These valves are set or actuated by the "expressive " and "loud play" register
mechanism hereinafter to be described.
From the wind chest the wind enters the four reed or sound boxes EE through the
openings d d which are also capable of being closed or opened by the valves d² d³.
These valves are moved by registers and for this motion the Bass, English horn, Flute
and clarionet registers are used. The reed boxes form four separate spaces which rest
against the wind chest F with the aid of felt and between which all communication is
closed. The connection of these boxes with the wind chest are rendered in this
manner thoroughly air tight.
There are provided two reeds and two reed boxes for each tone so that the sound
power of the harmonium can be doubled. When the valves are opened the wind
enters rapidly in the front reed box and only this front reed is sounded. When on
the other hand the rear valve d³ is also opened the two reeds are simultaneously
vibrated and the harmonium plays louder or with more intensity. The reeds flare
placed at the lower part of the air slots e e¹. When the key g or g' is depressed for
the purpose of playing so that the rear part of the same is raised to a certain height
this key will by means of its valve f free the passage or channel for the reed " and
the wind which is conducted either through one or through two reed boxes E to the
reed allows the same to be sounded.
The registers which are made use of in this combined piano and harmonium operate
upon the air valves d d³ which allow the wind to enter the front or rear reed box as
well as upon the "expressive" or "loud play" in order to allow the wind to proceed
from the collecting bellows to the wind chest. The registers are arranged above the
keys in the front board or wall of the piano and are provided in a well known manner
with knobs or buttons upon which is inscribed the description of the corresponding
register. The motion of the register is fully shown at a large scale in Figures 9
to 11.
The register knob h passing through the front ledge h' of the piano (see Figures 9

page_text: to 11) carries at the back a bolt 2 in which is formed an opening h³ having the form
of a slot. In this notch or slot is located one of the arms of the double armed lever i
which is movable in the projecting wooden part of the reed box E. The shorter
arm i presses against a plate k which is held by means of a small frame 11 so as to be
capable of turning round. While the lever arm c¹ presses from above downwards
against the plate k the plate m² has a tendency to press the valve upwardly under the
action of the spring m¹ and with the aid of the crank lever m and of the draw rod m³
of the valve. When the knob of the register is pulled out the lever arm i is moved in
the direction of the arrow I and the arm ¹ of the crank lever pushes the valve
downwardly whereby the pressure of the spring m³ is overcome and the corresponding
valve is opened. With reference to these valves which are used for the rear reed
boxes a similar cranked lever may likewise be employed. In this case the pro-
longation of the plate m² is pressed directly against the prolongation m² of the valve
in valves which allow of the "expressive" and "loud play" to be played and
determine the entrance of wind in the wind box F. In this manner the register
is rendered capable of being easily drawn out and kept steadily in the position thus
assumed.
The registers are placed in front and over the key board so as to be little disturbed
while the instrument is being played and yet to be easily accessible when they have
to be pulled out. The piano as already stated may have mechanism of any suitable
construction as well as pedals of the well-known or ordinary kind and it is furnished
with such an arrangement of parts that the said mechanism may be drawn back
by means of a peculiar decrescendo device when the piano only is intended to be
played and the hammers can be brought in contact with the felt of an anvil or
counter hammer to be hereinafter described. This arrangement is clearly shown
in Figures 5 and 6 while Figures 7 and 8 show the arrangement of the decrescendo
mechanism. The mechanism of the piano is arranged in a frame whose side walls B
are arranged to move upon the bolt A' of the frame A A. Thus these side walls
and with them the mechanism of the piano are rendered capable of being moved
away from the rest of the frame. It is to enable such removal to be accomplished
that the decrescendo mechanism is used in the manner hereinafter described. The
mechanism is usually and constantly pressed against the strings or cords by means
of a spring B2 whose lower end is fixed to the frame A while its upper extremity
rests against the side walls B. Too great a pressure of the mechanism is prevented
by means of the slant projections or blocks B3 which are arranged on the side walls
of the frame A. In order to draw back the mechanism the double lever o o¹ is made
use of and fixed to the frame A in such a manner as to be able to turn freely thereon
while it is provided with a cam-shape boss at the place where it passes by means of
its rod through a slot 2 formed in the side walls B. The short lever arm o' carries
an upright piece counter hammer or anvil y to which is fixed a bar covered over
with felt and serving as a damper to stop the bainmers. When now the lever is
turned by means of the decrescendo mechanism in the direction of the arrow III
Figure 5 the counter hammer or anvil comes at once with its felt in front of the
hammer and in this manner muffles the sound. When however the lever arm o¹ is
turned still further from the right to the left hand side in consequence of the
decrescendo mechanism being moved further forward then the cam shaped boss
is pushed against the front wall of the slot v² and moves the whole mechanisın
backwardly upon the bolt A. The hanımers are thus drawn so far back that they are
in connection with the felted anvil or counter hammer q which being at the same time
moved higher up prevents the hammer from striking the string or cords. The
decrescendo mechanism is let in the floor or bottom of the piano and is moved by
the knee of the player. In a slide guide F (Figures 7 and 8) moves the sliding
piece Qwhich carries two small boards P P capable of being turned over or folded in
a horizontal and in a vertical direction whereby the rounded off part wl in conjunction
with the spring w prevents the unintentional turning of the small board P. These
plates are shown close to one another in their expanded or unfolded state. A spring a
bears with a certain amount of pressure against the sliding piece Q and prevents its

page_text: moving automatically. The sliding piece Q is terminated at its rear end with a
projection R carrying a rod R' screwed therein. In the space thus formed between
the projection R and the rod R¹ is laid a lever pp (Figures 45 and 6) movable about
a centre or pin p₁ and whose arm directed outwardly rests against the double
lever o o of the decrescendo mechanism. The more the sliding piece Q is moved
(to the right or left hand side) by the knee of the player the more the lever o o¹ will
move in the direction of the arrow III and the less will the piano partake of the play
until at last it is entirely rendered mute and soundless. When it is therefore required
to play the harmonium alone nothing more is required than to push the decrescendo
mechanism thoroughly to the right hand side while at the same time depressing the
treadle a which sets the bellows in motion. When on the contrary the piano only is
required to be played the decrescendo mechanism is left in its left handed position and
the treadles a a are left alone or released so that the mechanism of the piano having
been brought back the playing takes place (with a silent key board as far as the
harmonium is concerned) as generally effected by piano players. In order to increase
the facility of operation of the various parts hinges D¹ are arranged between the
bottom part of the key board C and the key board ledge or support B which ledge or
support is firmly connected with the wood work forming the rear part of the reed or
sound boxes. When the hook which connects the wind chest with the reed boxes and
fixes the latter is released and the frame [2 is raised to a certain height the reeds
above the reed boxes can be set free after the removal of the mechanism.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed I declare that what I
claim is :-
1. A combined piano and harmonium in which with one and the same key board
the harmonium alone or the harmonium and the piano or the piano alone can be
played and in which the playing in these three different manners merely requires a
similar uniform pressure on the keys substantially as herein before described and
illustrated in the drawings annexed.
2. In a combined piano and harmonium as herein before described the arrangement
of the valves for the reeds or notes of the harmonium below the rear key lovers and
the arrangement of a removable reed or sound box E turning upon the hinge D¹
substantially as set forth.
3. In a combined piano and harmonium as herein before described the register
mechanism consisting of a knob h the lever i and the rotating valve k which regulates
the entrance of air either in the reed or sound box E or in the wind box F sub-
stantially as set forth.
4. In a combined piano and harmonium as hereinbefore described the use and
application of a decrescendo mechanism consisting of the folding parts P P sliding
piece Q lever ppl a counter hammer or anvil covered with felt and a cam shape
boss mounted in the frame B of the mechanism for weakening or reducing the
intensity of the music of the piano or for entirely arresting the action of the
hammers upon the string or cords and drawing back the frame of the mechanism
substantially as set forth.
5. The improved combined piano and harmonium arranged to act and combined
substantially in the manner and for the purposes hereinbefore described and
represented in the drawings hereunto annexed.
Dated this 20th day of June 1888.