Improvements in Recording Instruments for Electric Telegraphs.
Year: 1893

page_text: Date of Application, 15th Feb., 1893
Complete Specification Left, 15th Nov., 1893-Accepted, 3rd Feb.,
1894
PROVISIONAL SPECIFICATION.
Improvements in Recording Instruments for Electric Telegraphs.
We, ALEXANDER MUIRHEAD, Doctor of Science, and ROBERT HENRY
EDGAR, Electrician, both of No. 2 Princes Street, in the City of Westminster,
do hereby declare the nature of this invention to be as follows:-
Our invention has reference to improvements in the class of instruments referred
to in the Specification of Letters Patent No. 3,139 of 1877 granted to one of us in
conjunction with another.
They consist essentially of a narrow rectangular coil of insulated wire suspended
between the poles of a magnet of horse-shoe or other convenient shape and without
the soft iron core which is fixed inside the coil of the instruments hitherto
employed. The coil is suspended and held in position by a fibre or wire above and
beneath it and is connected to the aluminium frame which carries the glass siphon
by means of two fibres of silk or other suitable material. These two fibres,
together with the torsional elasticity of the stretched wire by means of which the
siphon is suspended, give the requisite directive force to the coil.
To produce the necessary vibration of the siphon we employ the following
device;
A small electro-magnet is fixed at one end of the bridge-piece carrying the
siphon suspension and beneath the iron core of this electro-magnet is a small
armature of iron attached to the stretched wire on which the siphon rides.
A vibratory current is passed through the coil of this electro-magnet from a make-
and-break apparatus of similar construction to that of an electric trembling-bell.
Sometimes we may fix the electro-magnet on a separate standard in proximity to
the iron armature.
The annexed drawing shows the parts of a recording apparatus essential to
illustrate our invention.
N, S, represent the pole-pieces of the magnet between which, C, the rectangular
coil of fine silk-covered copper wire is lightly suspended singly, top and bottom, by
fibres or wires, x, x, and connected by means of two fibres, d, d, attached at one
end to a light arm, a, a, fixed on the coil and at the other end, b, b, to the
cradle, F, in which the siphon, 8, 8, rests.
The torsion of the stretched wire, w, w, and the two fibres, d, d, give directive
force to the coil, C.
E, is the small electro-magnet fixed at one end of the bridge-piece, G, and, i, is
the small soft iron armature attached to a spring to which one end of the stretched
wire, w, w, is secured. V, V, is the make-and-break electro-magnetic arrangement
in electrical connection with the electro-magnet, E, and battery, B.
To prevent vertical vibration of the siphon we adjust a wire or other device as
shown at, H, to touch lightly the stretched wire, w, w, at a point near the
cradle, F.
1803

page_text: *
Improvements in Recording Instruments for Electric Telegraphs.
We, ALEXANDER MUIRHEAD, Doctor of Science, and ROBERT HENRY
EDGAR, Electrician, both of No. 2 Princes Street, in the City of Westminster,
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 :-
Our invention has reference to improvements in the class of instruments referred
to in the Specification of Letters Patent No. 3,139 of 1877 granted to one of us in
conjunction with another.
They consist essentially of a rectangular coil of insulated wire suspended
between the poles of a magnet of horse-shoe or other convenient shape and without
the soft-iron core which is fixed inside the coil of the instruments hitherto
employed. The coil is suspended and held in position by a fibre or wire above and
beneath it and is connected to the cradle or aluminium frame which carries the
glass siphon by means of two fibres of silk or other suitable material. These two
fibres, together with the torsional elasticity of the stretched wire to which the
siphon with its cradle is attached, give the requisite directive force to the coil.
To produce the necessary vibration of the siphon we employ the following
device;-
A small electro-magnet is fixed at one end of the bridge-piece carrying the
siphon suspension and beneath the iron core of this electro-magnet is a small
armature of iron attached to the stretched wire on which the siphon rides. A
vibratory current is passed through the coil of this electro-magnet from a make-
and-break apparatus of similar construction to that of an electric trembling bell.
Sometimes we fix the electro-magnet on a separate standard in proximity to the
iron armature.
The drawing annexed to our Provisional Specification shows the parts of a
recording apparatus essential to illustrate our invention.
N, S represent the pole pieces of the magnet between which the rectangular
coil C of fine silk covered copper wire is lightly suspended singly, top and bottom,
by fibres or wires x, x and connected by means of two fibres d, d, attached at one
end to a light arm a, a fixed on the coil and at the other end b, b to the cradle F
to which the siphon s, s is fastened by cement or other suitable means.
One of the
fibres d, d is tied or otherwise fastened to a part of the cradle F above the stretched
wire to, w and the other fibre is similarly secured to a part of the cradle below
such wire.
The torsion of the stretched wire w, wo and the two fibres d, d give directive
force to the coil C.
E is the small electro-magnet fixed at one end of the bridge-piece G and i is the
small soft iron armature attached to a spring to which one end of the stretched
wire to, to is secured. The bridge-piece G is supported by being attached in any
well-known or suitable way to a convenient part of the framework of the instrument.
We generally prefer to support it by means of a bar (not shown in the drawing)
projecting from the frame on which the coil c is suspended. V, V is the make-
and-break electro-magnetic arrangement in electrical connection with the electro-
magnet E and battery B.
To prevent vibration of the siphon occurring in other than the required direction
we adjust a wire or other device as shown at H to touch lightly the stretched
wire w, w at a point near the cradle F.

page_text: Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed, we declare what we
claim is:-
1. The mode of giving directive force to the rectangular coil of insulated wire
or the movable part of other apparatus by means of two fibres or wires together
with the torsional elasticity of a stretched wire or its equivalent, substantially as
set forth.
.
2. The mode of imparting vibration to the siphon of a recording instrument by
means of intermittent electric currents passed through an electro-magnet whose
armature is attached to the stretched wire or its equivalent on which the siphon
rides, substantially as set forth.
3. In a recording apparatus wherein the siphon rides upon a stretched wire or
its equivalent, the mode, substantially as set forth, of preventing vertical vibration
of the siphon by limiting the vibration of the wire at a point near the siphon-
carrying cradle.
4. The recording instrument comprising a rectangular coil working between the
poles of a magnet connected to a siphon-carrying cradle or its equivalent by a
suitable number of fibres, such cradle being supported by a stretched wire or its
equivalent, and means for imparting vibration to the siphon in the required
direction with reference to the recording slip, and means for preventing vibration
of such siphon occurring in any other direction substantially as set forth.
Dated this 15th day of November 1892
A. F. SPOONER,
124, Chancery Lane, W.C., Agent for the Applicants.