IMPROVEMENTS IN THE STOP MECHANISM FOR ORGANS, HARMONIUMS, AND SIMILAR INSTRUMENTS
Year: 1879

page_text: A
PROVISIONAL SPECIFICATION left by John Albert Reinhold Hildebrandt
at the Office of the Commissioners of Patents on the 14th July 1879.
communication from abroad by August Grüters, of Crefeld, in Germany.
JOHN ALBERT REINHOLD HILDEBRANDT, of Manchester, in the County of Lancaster,
Engineer and Patent Agent. "IMPROVEMENTS IN THE STOP MECHANISM FOR
ORGANS, HARMONIUMS, AND SIMILAR INSTRUMENTS." [A communication from abroad
by August Grüters, of Crefeld, in Germany.]
The Invention has for its object an arrangement for organs, harmoniums and the
like instruments by means of which any stop may be played or brought into action
from any manual or pedal independently of each other. In order to explain the
manner in which that object is attained the following description of the arrangement
refers chiefly to harmoniums, but is equally applicable to organs and other similar
instruments with such modifications as will be well understood by persons acquainted
with this class of work.
A note is sounded when a valve closing an aperture in the wind chest is lifted
from its seat by depressing the free end of a double lever, to the other end of which
the valve is secured. This is effected by a suitably guided spindle which rests on
the aforesaid free end of the lever, and to this spindle the motion of a key in any
manual of keys or pedals is communicated by the interposition of a projection on a
bracket supported on a pin through, or a collar on, the spindle, but which bracket
is free to turn on the spindle. This bracket is of a peculiar shape, and has two
projections. One of them points upwards and another points downwards, and fits
into a bar or rod running parallel to the row of spindles, and which bar is linked to
fixed points, the links describing the same radius as the lower projections on the
brackets which engage the rail. This bar receives motion from a bellerank lever,
to which the drawbar of the stoppull is jointed, and when the latter is drawn the
bar or rod engaging the lower projections of the brackets on the spindles moves
from one side to the other and thus turns the said bracket through a part of a
revolution on the spindle. Before this movement is effected the upper projection
of the bracket is in such a position that the thin end of an inclined plane attached
to the underside of each key is opposite the upper projection of the bracket, and
consequently when the key is pressed down the said projection, and the inclined
plane do not come into contact with each other, hence the movement of the key is
not communicated to the spindle and no effect is produced. When, however, the

page_text: stop is drawn all the brackets on the. spindles connected with the stop make part
of a revolution on the spindle, and thus bring the upper projection of the bracket
Lopposite the thick end of the inclined plane on the key, and a depression of the
latter is now communicated through the bracket to the spindle, and the valve on
the windchest is opened. It will be observed that a row of spindles is required for
_each_row_of reeds or valves, and that there are as many brackets with their
Lattendant mechanism on each spindle as there are manuals, and that as many
stop pulls are required for each stop as there are manuals.
Thus-it-will be-seen-that-if-a-certain stoppull.is.not.drawn the corresponding key,
keys or pedals, may be pressed down, as they are when playing on the instrument,
without lifting the valve from the aperture in the windchest, as the keys only
actuate the spindles by means of an intermediate piece which is interposed by the
action of the stoppulls and the intermediate mechanism described, there being as
many spindles to each key as there are stops or rows of reeds or valves, and there
being a stop pull with its attendant mechanism for each manual it will be understood
that each stop may be played from any manual.