Improved Methods of Varying the Resistances of an Electric Circuit, specially applicable to Musical Instruments.
Year: 1891

page_text: Date of Application, 23rd Dec., 1891
Complete Specification Left, 23rd Sept., 1892-Accepted, 17th Dec., 1892
PROVISIONAL SPECIFICATION.
Improved Methods of Varying the Resistances of an Electric Circuit,
specially applicable to Musical Instruments.
I, PARIS EUGENE SINGER Gentleman 6 Victoria Road, Kensington London
do hereby declare the nature of this invention to be as follows:--
The object of my invention is to enable a performer on a musical instrument
actuated by electricity to vary the intensity of any note by increasing the pressure
of the finger over the key operating it.
In carrying out my invention I place a receptacle containing a quantity of carbon
powder in proximity to each key and it is arranged that depressing the key causes
the powder to close the electric circuit which operates the instrument. Further
pressure on the key compresses the powder, thereby lessening the resistance and so
intensifying the sound. The movement of the key also serves by causing the
movement through the carbon powder of a bundle of insulated wires or otherwise
to prevent it from hardening into a cake. For certain effects all the receptacles
may be brought into use by a pedal. Carbon plates may be used instead of the
powder.
The same effect may be produced by attaching to each key a metallic rod
which slides over a coiled naked wire, or over the terminals of coils suitably fixed
and of the required resistance.
I wish it to be understood that the method herein set forth of altering the
resistance in an electric circuit by compressing a column of carbon powder may be
used for other purposes.
Dated this 22nd day of December 1901
P. E. SINGER.
COMPLETE SPECIFICATION.
Improved Methods of Varying the Resistances of an Electric Circuit,
specially applicable to Musical Instruments.
I PARIS EUGENE SINGER of 6 Victoria Road Kensington 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 object of my invention is to enable a performer on a musical instrument
actuated by electricity to vary the intensity of any note by increasing the pressure
of the finger on the key by which it is sounded.
In carrying out my invention I place a receptacle containing a quantity of carbon
powder or equivalent material in proximity to each key and so arrange it that the
depression of a key will through the interposed carbon close the electric circuit
which operates the instrument. Further pressure on the key will by compressing
the carbon powder lessen the resistance and thereby intensify the sound.
In the accompanying drawings
Fig. 1 shews so much of an electrical pianoforte as will serve to explain the
manner of carrying out my invention and
Fig. 2 is a similar view illustrating a modification of my mode of varying the
touch in a pianoforte.
In Fig. 1A is the pianoforte key fitted with a contact spring a in electrical
connection with the battery. B is a plank running across the pianoforte immediately
below the keys in which are bored out cylindrical recesses (one for each key) to
[Price Rd71

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receive the carbon powder which is to form a link in each key circuit. 6 is a disc
of ebonite fitting the bottom of the recess in the plank B and carrying a metal
plate 6* in contact with the wire that leads from the battery. Resting upon this
disc is a rigid tube which serves to contain a tube d of india rubber which is
charged with carbon powder. This tube d stands up somewhat higher than the
tube c and above it is placed an ebonite disc b' which carries a metal plate 1* on
its upper side and a metal plate 62* on its underside, the two plates being connected
together by a rod e which extends deep down into the carbon powder for the
purpose to be presently explained.
The disc is supported by a helical spring f which surrounds the tube c
and occupies the space between it and the cylindrical recess in the plank B.
It will now be understood that if pressure is put upon the key A by the finger
of the player the spring a will press upon the metallic plate 6* of the disc cause
the spring to yield and bring the metal plate 62* down upon the carbon in the
elastic tube d and compress the carbon therein. This compression of the powdered
carbon will in proportion to the energy exerted by the player establish a circuit of
more or less resistance and thereby vary the intensity of the note sounded as
desired.
To prevent the powdered carbon becoming solidified by the repeated pressure to
which it is to be subjected the rod e is fitted with radial arms which through the
end way movement of the rod up and down in the tube d will loosen or disintegrate
the powdered carbon and prevent it caking. I may remark that in place of the
powdered carbon small discs or pellets of carbon may be employed the same being
placed in the tubular receptacle d and pressed upon by the metallic plate 62*.
In the arrangement shewn in Fig. 2 the like result is obtained but by somewhat
different means. In place of the carbon a coil of naked wire within the key
circuit is supported by a fixed cylinder immediately below the key A and fitted to
this key is a spring a connected with the battery. This spring is so arranged that
when the key is depressed it will come in contact with the face of the coil and as
it moves down over the coil will reduce the resistance to the current in proportion
to the depression of the key.
A modification of this arrangement would be to bring the spring a in contact
with a succession of terminals of coils thus short circuiting the current in pro-
portion to the travel of the contact spring.
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:
The means above described for altering the resistance of electric circuits in keyed
musical instruments with the object of enabling the player to vary the expression
of the musical sounds produced by the pressure on the keys.
Dated this 23rd day of September 1809
NEWTON & SON,
Agents for the Applicant.