IMPROVEMENTS IN WIND-CHESTS AND SOUND-BOARDS, AND IN THE DRAWSTOP AND KEY MECHANISM APPERTAINING THERETO FOR ORGANS AND OTHER SIMILAR MUSICAL INSTRUMENTS
Year: 1880

page_text: PROVISIONAL SPECIFICATION left by Carl Kesseler at the Office of the
Commissioners of Patents on the 5th March 1880. A communication from
Herr Friedrich Albert Mehmel, of Stralsund, in the Empire of Germany.
CARL KESSELER, of 63, Mohrenstrasse, Berlin, W., in the Empire of Germany,
Civil Engineer and Patent Solicitor. "IMPROVEMENTS IN WIND-CHESTS AND
SOUND-BOARDS, AND IN THE DRAWSTOP AND KEY MECHANISM APPERTAINING
THERETO FOR ORGANS AND OTHER SIMILAR MUSICAL INSTRUMENTS."
A com-
munication from Herr Friedrich Albert Mehmel, of Stralsund, in the Empire of
Germany.
By preference I arrange the pallets to hang nearly vertically, but sufficiently
overhung to ensure their lying well against their seats; the ends project a short
distance into the wind-chest.
Suitably placed beneath the pallet-ends are lever-supporting-bars, hinged so as
to be capable of being partly canted over, as will be presently explained, and in
grooves across these bars work levers bent at an obtuse angle and pivotted at the
bend; one end of each of these levers is so placed that when moved sufficiently it
may touch the overhanging end of the pallet opposite to it and open the pallet. At
right angles to these bars and lying horizontally beneath them is a light bar,
preferably of wood, which I term the key bar, and this is connected by means of
studs and short screwed rods, or in any other convenient manner, with the aforesaid
bent levers. The end of this key bar is actuated by one arm of a bell-crank, the
other arm being connected with the key tracker; this second arm is prolonged back
beyond the former arm and carries a balance weight, the whole lever being then in
form of a T and pivotted at the junction of the arms. Beneath the wind chest
are arranged bell cranks or angles corresponding in number to the lever-supporting-
bars; one arm (generally the vertical one) of each angle is connected with the draw
stop action, and the other by means of screwed rods or the like to the lever-
supporting-bar.
Suitable "buttons" are of course provided wherever necessary upon the screwed
rods, et cetera.
Now by this arrangement I make the draw stop mechanism the primary element,
the key movement being the secondary element; the operation of the whole is as
follows:-
When a stop is drawn the first arm of the bell-crank or angle in that system is
moved, thereby (through the other arm and the intervening screwed rods, et cetera)

page_text: moving the lever-supporting-bar, and bringing the end of the bent lever in the key
action system nearly or quite into contact with the pallet above; this of course
applies to the whole number of levers, pallets, et cetera, belonging to or in connection
with that particular stop. Now when a key is depressed it moves the balanced
bell-crank or angle in connection with it, which moves the key bar which, as
already shown, by its connections actuates the bent levers which open the pallets.
If one stop be drawn it will be evident that only one lever-supporting-bar will be
so placed that the bent levers which it carries will be in connection with the pallets,
therefore when the keys are played upon only those pallets answering to that stop
which has been drawn will be opened and only one row of pipes will sound. The
bent levers belonging to the other stops, will rest clear of the pallets, so that
although they are moved by the key action they produce no effect upon the pallets
until brought into position by the performer drawing the stops belonging to them.
A suitable rest is provided for the balance weight on the arm of the three-armed-
lever to rest on when not in use, and suitable openings are formed in the wind
chest, preferably in its under side, which are closed by covers in any convenient
and air-tight manner.