IMPROVEMENTS IN APPARATUS FOR SIGNALLING
Year: 1874

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1.ETTERS PATENT to John Thomas Gent, of Leicester, Electrician,
for the Invention of "IMPROVEMENTS IN APPARATUS FOR SIGNALLING."
PROVISIONAL SPECIFICATION left by the said John Thomas Gent
at the Office of the Commissioners of Patents, with his Petition,
on the 14th December 1874.
I, JOHN THOMAS GENT, of Leicester, Electrician, do hereby declare
the nature of the said Invention for "IMPROVEMENTS IN APPARATUS FOR
SIGNALLING," to be as follows:-
My said Invention consists of the arrangements or combinations of
parts herein-after described of apparatus for signalling, whereby sig-
nalling is effected with great certainty and economy, and with little risk
of derangement of the apparatus.
My Invention effects the ringing of an electric bell, and the actuating
of an indicating tablet, the ringing of the bell being maintained or
continued during the time that the person signalling acts by pressure of

page_text: "
otherwise upon the tube or wire or other agent by which the apparatus
is actuated.
In the room or at the place where the signal is to be given I fix an
electric bell of the ordinary construction, and also an indicating tablet
of the ordinary construction.
The indicating tablet is carried by a wheel, on the periphery of which
is a notch, and a tooth carried by a vertical sliding rod engaging in the
said notch locks the wheel, and sustains the tablet in its raised position.
On the rising of the said rod the tooth is raised from the notch, and the
wheel being now at liberty to move the weight of the tablet causes it to
fall, and to indicate by its motion the room or place from whence the
signal has been sent.
The raising of the vertical sliding rod described closes the circuit of
the voltaic battery forming part of the electric bell apparatus, and causes
the bell to ring in the following way :-Immediately over the top of the
sliding rod described a horizontal metallic spring is situated, the free end
of the said spring terminating a short distance above the top of the
sliding rod when the said rod is in its lowest position, and being pressed
on its under side by the top of the said sliding rod when the said rod is
raised, so as to liberate the indicating tablet. A wire from one end of
the voltaic battery is connected with the spring, and a wire from the
other end of the voltaic battery is connected with the vertical sliding
rod.
When the said sliding rod is raised, and brought thereby in contract
with the spring, the voltaic circuit is closed, and the electric, bell rings
so long as the circuit is kept closed by the raised sliding rod. The parts of
the rod and spring which come into contact when the rod is raised are
tipped with platinum.
I prefer to effect the raising of the sliding rod described by the use of
an air chamber of the kind commonly employed with pneumatic
bells. The said air chamber is situated immediately under the bottom
end of the sliding rod and between a disc fixed on the bottom of the
rod and another disc carried by a fixed support. The air tube from the
said air chamber terminates in the room or at the place from which the
signal is to be sent, and is provided with any of the well-known con-
trivances by pressing or otherwise acting on which a current of con-

page_text: densed air may be sent along the tube. The said condensed air reaching
the air chamber expands the said air chamber, thereby lifting the ver-
tical sliding rod, liberating and letting fall the indicating tablet, and at
the same time closing the electric circuit and bringing the electric bell
into action.
As the action of the apparatus depends on the raising of the vertical
sliding rod described it may be put into operation by the pulling of a
wire or by other equivalent mechanical arrangement which being
operated upon will raise the said rod.
Although I have only described one indicating tablet and vertical
sliding rod and spring, yet any number of the said tablets and adjuncts
connected with different rooms or places may be connected with the
same electric bell, the raising of any one of the said sliding rods ringing
the clectric bell, and showing the room or place whence the signal was
sent.
The whole of the electrical arrangement of the apparatus may be
contained in a small box, and from the shortness of the voltaic circuit
a small and inexpensive voltaic battery is sufficient to work the
apparatus.
▸ SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said John Thomas Gent in the Great Seal Patent Office
on the 12th June 1875.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOHN
THOMAS GENT, of Leicester, Electrician, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Fourteenth day of December, in the year
of our Lord One thousand eight hundred and seventy-four, in the thirty-
eighth year of Her reign, did, for Herself, Her heirs, and successors, give
and grant unto me, the said John Thomas Gent, Her special licence that
I, the said John Thomas Gent, my executors, administrators, and assigns,
or such others as I, the said John Thomas Gent, my executors, admini-
strators, and assigns, should at any time agree with, and no others,
from time to time and at all times thereafter during the term therein
expressed, should and lawfully might makè, use, exercise, and vend,

page_text: within the United Kingdom of Great Britain and Ireland, the Channel
Islands, and Isle of Man, an Invention for "IMPROVEMENTS IN APPARATUS
FOR SIGNALLING," upon the condition (amongst others) that I, the said John
Thomas Gent, my executors or administrators, by an instrument in
writing under my, or their, or one of their hands and seals, should
particularly describe and ascertain the nature of the said Invention,
and in what manner the same was to be performed, and cause the same
to be filed in the Great Seal Patent Office within six calendar months
next and immediately after the date of the said Letters Patent.
NOW KNOW YE, that I, the said John Thomas Gent, do hereby
declare the nature of my said Invention, and in what manner the same
is to be performed, to be particularly described and ascertained in, and
by the following statement, reference being had to tho Drawing hereto
annexed, and to the figures and letters marked thereon, that is to
say :-
My said Invention consists in the method of and arrangement and
combination of parts herein-after described of apparatus for signalling,
whereby signalling is effected with greater certainty and economy, and
with less risk of derangement of the apparatus than hitherto, and is
applicable where electric bells are usually employed.
By my Invention I effect the ringing of an electric bell and the
actuating of an indicating tablet, the ringing of the bell being continued
during the whole of the time the person signalling acts by pressure or
otherwise upon the tube or wire or other contrivance by which the
apparatus is actuated.
To make my Invention better understood I will proceed to describe
the same by reference to Figuro 1 of the accompanying Drawing, which
is a sectional side elevation shewing my improvements.
In the room or at the place where the signal is to be given I fix an
electric bell Z of the ordinary construction, and also a signal plate or
indicating tablet D of the ordinary construction.
The indicating tablet D is carried by a wheel P, on the periphery of
which is a notch K. A tooth X carried by a vertical sliding rod C takes
into the notch K so as to lock the wheel P and sustain the tablet D in
its raised position. On the rising of the rod C (which slides in the fixed

page_text: support I) in the manner herein-after described the tooth X is raised
from the notch Ķ, and the wheel being then free to move will allow the
tablet D to fall by its own weight against the glass M so as to indicate
through the glass the room or place from which the signal has been sent.
At the same time the rising of the vertical sliding rod C closes the
circuit of the voltaic battery V forming part of the electric bell apparatus
(so as to cause the bell to ring) in the following manner :-A pin N is
fixed on the vertical rising rod C, which pin when the rod is raised
strikes against and raises the end a of the crank arm L pivotting at b,
thereby causing the upper end c of the arm L to press the spring E
against the point F and complete the clectric circuit, and allow the
current from the positive pole P' of the battery V to pass along the
wire d and spring E to the point F, and along the wire e to the electric
bell Z, thereby ringing the bell, and the current then passes through the
wire to the negative pole N' of the battery V.
In the Drawing the battery V and boll Z are merely shewn to point
out their position, and are drawn to a smaller scale than the other parts
of the apparatus. It will thus be understood that the bell will continuo
to ring so long only as the tooth of the vertical sliding rod is kept above.
the periphery of the wheel P and the points E and F are kept closed in.
contact.
I prefer to effect the raising of the sliding rod C by employing an air
chamber B of the kind commonly used with pneumatic bells. The said
air chamber B is situated immediately under the lower end of the
sliding rod and between a disc R fixed on the bottom of the rod and the
fixed support H. A is the air tube from the air chamber B, such tubo
terminating in the room or at the place from which the signal is to be
sent, and it is provided with any of the well-known contrivances, by
pressing or otherwise acting on which a current of condensed air may be
sent along the tube A. The said condensed air reaching the air
chamber B expands the same, thereby lifting the vertical sliding rod C,
liberating and letting fall the indicating tablet D, and at the same time
closing the electric circuit and bringing the electric bell into' action, as
herein-before described.
As soon as the vertical sliding rod C is allowed by the contraction of.
the air chamber B to rest upon the circumference of the wheel P or by
the replacing of the tablet D to fall into the notch K again the contact

page_text: between the points E and F will be broken and the bell will cease to
ring.
Instead of the arrangement of arm L and spring E herein-before
described I can employ a horizontal metallic spring, the free end of such
spring terminating a short distance above the top of the sliding rod
when the rod is in its lowest position. A wire from one end of the
voltaic battery is connected with this spring, and a wire from the other
end of the battery is connected with the vertical sliding rod. When the
said sliding rod is raised, and thereby brought in contact with the
spring the voltaic circuit is closed and the electric bell rings so long as
the circuit is kept closed by the raised sliding rod. The parts of the rod
and spring, which come into contact when the rod is raised are tipped
with platinum.
Figure 2 shews a modification in which a crank lever T is employed
in place of the sliding rod C, Figure 1. The other parts being similar
to those shewn in Figure 1 are marked with similar letters of reference.
As the action of the improved apparatus depends, as herein-before
described, on the raising of the vertical rod C or the moving of the crank
lever such rod or such crank lever may if desired be put into operation
by means of a line, or by other suitable means, which being acted upon
will raise the said rod or move the said lever.
Although I have only described and shewn one indicating tablet and
vertical sliding rod and spring it will be understood that any suitable
number of the said tablets and accessories in communication with
different rooms or places may be connected with the same electric bell,
the raising of any one of the said sliding rods ringing the electric bell
and indicating the particular room or place whence the signal was
sent.
The whole of the electrical arrangement of the apparatus may be
contained in a small box, and from the shortness of the voltaic circuit
a small and inexpensivo voltaic battery is sufficient to work the
apparatus.
Having thus described my said Invention and the best means with
which I am acquainted for carrying the same into effect, I wish it to be
understood that I do not confine myself to the precise details herein laid
down, but what I do claim is,-

page_text: Firstly. The method of ringing an electric bell and actuating an
indicating tablet by the moving of a sliding rod or a lever operating so
as to close the circuit and at the same time release the indicating tablet
and allow it to fall, as herein-before described.
Secondly. The combination and arrangement of the battery, the bell,
and the indicating tablet with the other parts of the apparatus, whereby
the whole may be contained within the same frame or box and covered
by the glass through which the signals are shown, as herein-before
described.
In witness whereof, I, the said John Thomas Gent, have hereto
set my hand and seal, this Eleventh day of June, in the year of
our Lord One thousand eight hundred and seventy-five.
JOHN THOMAS GENT. (L.s.)