IMPROVEMENTS IN ELECTRICAL SIGNAL APPARATUS FOR RAILWAY PURPOSES
Year: 1880

page_text: LETTERS PATENT to William Robert Lake, of the Firm of Haseltine, Lake,
& Co., Patent Agents, Southampton Buildings, London, for an Invention of
"IMPROVEMENTS IN ELECTRICAL SIGNAL APPARATUS FOR RAILWAY PURPOSES."
A communication from abroad by Alfred Lemaire and Edmond Lebrun, both
of Paris, France.
PROVISIONAL SPECIFICATION left by the said William Robert Lake at
the Office of the Commissioners of Patents on the 7th October 1880.
WILLIAM ROBERT LAKE, of the Firm of Haseltine, Lake, & Co., Patent
Agents, Southampton Buildings, London. "IMPROVEMENTS IN ELECTRICAL SIGNAL
APPARATUS FOR RAILWAY PURPOSES." [A communication from abroad by Alfred
Lemaire and Edmond Lebrun, both of Paris, France.]
This Invention relates to apparatus for signalling on railways, which apparatus
is particularly adapted for use in connection with single lines. It comprises the
combination of various parts hereinafter described, and an important feature of the
said Invention consists in the mechanism for operating the signals showing "line
clear" or "train on line."
In working I employ two identical sets of apparatus, one fixed at each station
at the end of a telegraphic line-wire; they are placed near to the outgoing switch
of each station or upon the platform or in any suitable place, but always in such
a position as to be visible to the whole staff, and so that engine-drivers and guards
cannot run a train upon any single track that connects two stations without being
fully able to ascertain for themselves the position of the signal which they are to
obey. Furthermore, the parts are so combined and arranged as to maintain the
corresponding apparatus of the two stations in gear regularly and forcibly, so that
it shall not be possible to set them at "line-clear" together.
For sending currents I employ a combined arrangement comprising a pusher-
switch and a shifting-switch.
In carrying the said Invention into practice I provide at each one of two
stations, forming a circuit, an electric signalling apparatus, a pusher-switch, a
shifting-switch, and an electric bell-arrangement. The signalling apparatus consists
of a board or plate carrying a series of terminals, and supporting a vertical board

page_text: or plate upon which I mount two electro magnets to operate a swinging frame,
which is suspended in its centre, and carries a double screen by which the red light
shown by a suitably arranged disc or the white light shown by a similar disc are
alternately covered or uncovered. These lights are produced by lamps placed
before suitable reflectors, and the rays are refracted by the reflectors. During
daylight the lamps need not be lighted, as the colors of the glass of the aforesaid
discs are sufficiently apparent without artificial light. The whole of this signalling
apparatus is enclosed in a box provided with sight holes for the discs in front and
with chimneys for the lamps.
The impulse to the swinging beam causing the same by changing its position
to uncover the red or white lights or glass is produced by the shock of levers or
pallets actuated by the aforesaid electro-magnet; these levers or pallets strike
upon the ends of the arms of the swinging frame when the respective electro-
magnets are under the influence of a current, the pallets being suddenly attracted
towards their respective magnet. Thus when a current is passing through the first
electro-magnet, the pallet being suddenly attracted will with its lower end strike
the lower end nearest to it of the swinging frame, which will thereby be oscillated
and brought into position to close or cover the red light and uncover the white
light, that is to say, the apparatus may then show "line clear." In this position
the opposite side of the swinging frame will clutch the upper arm of the pallets of
the second electro-magnet in the same manner as it clutched the upper end of the
pallet of the electro-magnet first herein referred to, which has released it from its
position before impelling its lower part. When a current is passing through the
first named electro-magnet and the swinging frame is in such a position as to show
the red light, the pallet of this magnet has no effect upon the swinging frame, but
the current at the moment the pallet or lever comes into contact with the soft iron
core of its electro magnet passes through the said pallet, the upper part of which
by means of small springs makes contact with terminals near its upper end which
communicate with the earth wire. The passing of this current actuates the bell-
arrangement, which ceases to operate at the moment of contact of the said springs,
whereupon the terminals and the pallet return to their vertical position by the
action of small coiled springs.
The pusher-switch which I employ for the purposes of my Invention is con-
structed as follows, that is to say:-It consists of a wooden box provided with a
lid carrying a pushing-stud or button provided with a spring, acting when it is
depressed upon the extremity of a contact piece (which in its normal position is
always in contact with a second contact piece), so as to put it in contact with the
end of a contact piece which is connected with a terminal of the signalling
apparatus, which by means of suitable wires is in electric connection with the
signalling mechanism. The first named contact piece in the aforesaid box is
connected with the line-current, and another contact piece also in the said box
as stated is connected with a terminal in such manner that ordinarily the terminals
of the line and the shifting-switch, hereinafter described, are connected, and the
signalling apparatus is ordinarily cut out of circuit, and when the latter and the
line are connected by the contact of the two contact pieces by depressing the stud
of the pusher-switch, as stated, the current will actuate the bell-arrangement at
the distant station and the required signals will be given.
The shifting switch is constructed as follows, viz:-
It consists of a wooden box having two terminals, one for line clear and one for
"train on line," and also central terminal in connection with a terminal upon the
pusher-switch hereinbefore described. Upon the central terminal is mounted a
switch-crank which serves to direct the current arriving from the line through the
pusher switch to the signalling apparatus above described to actuate the latter.
Ordinarily the crank connects the central terminal with the signalling apparatus
so as to cause the same to show "train on line."
The crank of this switch is held in the side of a lid covering the box in which it
is mounted, which lid is hinged to the said box and is secured by a suitable lock

page_text: on the opposite side, so that this switch cannot be shifted so as to cause the signal
"line clear" to be shown unless the lock be unfastened, which allows the lid to be
opened and the crank to be turned round the axis of the central terminal of this
switch.
In consequence when the "up" station, for instance, demands to have the line
clear it will do so by acting upon the button of its pusher-switch so as to operate
the bell arrangement of the "down" station as above stated. The latter answers
by depressing the button of its switch. The current coming from the line passes
through the pusher-switch, and as the signalling apparatus is cut out of circuit so
far as this switch is concerned, the current flows from there to the central terminal
of the shifting-switch, passes through the terminal thereof to go to the terminal of
the signalling apparatus, and lastly to actuate the bell arrangement of the "up"
station, as herein before explained, after which the latter station opens the lid of
its shifting switch, places the switch to indicate "line clear," and presses twice upon
the button of its pusher-switch to inform the down" station by two rings of the
bell that it is ready to have its signal set to "line clear." The "down station
by pressing upon its stud sends the current, which, passing through the proper
wires sets the signal of the "up" station.
"
"
When the train is sent off, the "up" station shuts the lid of its shifting switch
after having put the switch back to "train on line," and three times depresses the
button of its pusher-switch. The "down" station answers by pressing again upon
the button of its pusher-switch, and the current then passing through the "train
on line" signal of the switch blocks the line for the "up" station. What has been
said for the "up" station applies to the "down" station, but in the reverse order.
The station which is required to clear the line must do so only by simply
depressing the button of its pusher-switch.
The station requiring the line to be cleared cannot itself clear it nor have it
cleared before having had the answer of the adjacent station, and having set its
pusher switch to "line clear."
In some cases it may be inconvenient, to light the lamps of the apparatus in the
evening; in that case the apparatus may have a double arrangement with two red
glasses and two white glasses, the lower disc of the swinging frame will be red and
the upper disc white.
In day time four discs will be seen simultaneously, but it will be understood
that the line is clear when like colours are seen in the same vertical line, otherwise
the line will be blocked.
As the upper discs (or in some cases the lower ones) are constantly illuminated,
the apparatus operates at night in substantially the same manner as that above
described.

page_text: and
Figure 2 is a sectional side elevation of the same in front of the swinging frame.
Figures 3 and 4 shew the pusher-switch in section and in plan with the cover
and pusher removed.
Figures 5 and 6 shew in section and in plan the two-way switch or commutator.
Figure 7 is a diagram illustrating a modification of this Invention.
In carrying the said Invention into practice I provide at each of the two stations
to be placed in communication an electric signalling apparatus X, a pusher-
switch N³, a two way switch M, and an electric bell V.
The signalling apparatus (Figures 1 and 2) consists of a board or plate A, carrying
terminals F, T2, O, T, S, C, and supporting a vertical board or plate B, upon which
are mounted two electro magnets M and M³ for operating the swinging frame N ;
this frame is suspended at n, and carries the double screen N', which allows the
alternate closing of the red light shewn by the disc P, and the white light shewn
by the disc P¹. These lights are produced by lamps such as that shewn at Q',
placed before reflectors q¹, by which such lights are reflected. During daylight the
lamps need not be lighted, as the red color of the glass of the disc P and the white
glass of the disc P¹ will be sufficiently apparent without artificial illumination.
The whole of this signalling-apparatus in enclosed in a box R, provided in front
with sightholes for the disc P and P¹, and also with chimneys for the lamps Q.
The impulse to the swinging frame for causing the same by changing its position

page_text: to uncover the red or white light is imparted by the impact of the pallet or arma-
ture Vor V of the electro-magnet upon the end n³ or n³ of the arm of the
swinging frame when either of the said pallets is under the influence of a
current, the pallet then being suddenly attracted towards the magnet. Thus when
the parts are in the position shewn in the Drawing, and a current passes through
the electro magnet M, the pallet V₁ being suddenly attracted, will, by its end V³,
strike the end n of the swinging frame, which will be brought into such a position
as to cover the red light and uncover the white light, that is to say, the apparatus
will be set to indicate "line clear." In this position the swinging frame will be
engaged by the upper arm 3 of the pallet Vs of the electro magnet M' in the same
manner as it was engaged by the upper end of the pallet V₁ of the electro-
magnet M, by which end the said frame was released before the impulse causing it
to change its position was imparted to the lower end thereof.
When a current is passing through the electro-magnet M, and the swinging frame
is in the position shewn in the Drawing, the pallet has no effect upon the said
swinging frame; but the current at the moment the pallet comes in contact with
the soft iron-core of the electro-magnet passes through the said pallet, the upper
part of which, by means of the small springs r, is brought in electrical contact
with the terminal which communicates with the earth-wire. This current in
passing actuates the bell, which ceases to operate at the moment of contact of the
springs or with terminal 2 or 3, and the pallet is returned to its vertical
position by the action of a small spiral spring.
The operation of this apparatus is as follows, that is to say:
-A current arriving
through the terminal F passes through the electro-magnet M' to the terminals Č
and C, and to the bell at V. A current arriving by the terminal O passes through
the electro-magnet M, thence to the terminal C (through the branch at c), and
thence to the terminal C₁ of the bell V. Finally, a current passing through the
terminal T connected with the earth passes through the branch t and the
terminal T, or through the terminals 2 and 3, thence to the terminal S, and
subsequently to the terminal T¹ of the bell V.
Thus a current arriving at F in the switch M² serves to set the signals to indicate
"train on line," at the same time ringing the bell, or the said current serves only
to ring the bell when the signals are already set to this position. A current
arriving at O in the switch M2 causes the apparatus to indicate "line clear," and
actuates the bell at V; the earth wire of the line serves to establish communication
with the springs which form the end or upper extremity of the pallets, and causes
the bell to operate.
The pusher-switch N₁ (Figures 3 and 4) consists of a wooden socket furnished
with a cover carrying a pushing-stud or button provided with a spring, and when
pressure is exerted upon the said button the extremity of a contact piece a (which
in its normal position is always in contact with the contact piece a¹) is put in
contact with the end of another contact piece a², which is connected with the
terminal S; the latter is connected with the terminal T2 and the signalling
apparatus. The contact piece a is connected with the line-wire by the terminal L,
and the contact piece a¹ is connected with the terminal R in such manner that
ordinarily the terminals L and R are connected, and the terminal S is ordinarily
isolated. When contact of the two contact pieces a and a² is caused by depressing
the stud of the pusher-switch at one station, the "up" station for instance, and
the terminals S and L are thereby connected, the current passing from the
terminal T through the terminal S will actuate the bell at the other station (in
this case the 'down" station), and the line will be made clear for or blocked
against the same as may be required.
"
The two way switch Ms (Figures 5 and 6) consists of a wooden socket having
two terminals F, O, and a central terminal U in connection with the terminal R
upon the pusher switch N. Upon the said central terminal is mounted a switch
crank or manipulator u¹ which serves to direct the current, arriving from the line

page_text: through the terminal R to the terminals F or O connected with corresponding
terminals upon the signalling apparatus X. Ordinarily the switch-crank u¹ connects
the central terminal U with the terminal F, and the handle of the switch is held
in the side of a cover hinged at m to the said socket, and secured by a padlock
or other device on the opposite side, so that this switch cannot be directed to the a
terminal O unless the cover be unlocked, in which case the said cover can be
opened and the switch-crank may be turned around the axis of the central
terminal.
When therefore the attendant at one of the stations, say, the "up" station,
requires to have the line clear, he depresses the button of the pusher switch N² so
as to operate the bell of the other station, as above stated. The attendant at the
latter answers by depressing the button of the switch N2 at the "down" station.
The current coming from the line passes through the terminals L and R (the
terminal S being disconnected), goes from there to the central terminal U of the
Bwitch M2, passes through the terminal F thereof to a terminal of the signalling
apparatus X, and actuates the bell of the " up" station, as herein before explained,
then the attendant at this station opens the cover of his switch M², places the
switch-crank upon the contact piece O, and presses twice upon the button of the
switch N to inform the "down" station by two rings of the bell, that the "up"
station is in readiness to have its signal opened.
The attendant at the "down'
station by pressing upon the switch stud sends the current, which passing through
the contact piece Ŏ of the "up" station actuates the signalling apparatus. When
the train is sent off the attendant at the " up" station closes the cover of the
commutator M' at the said station after having put the switch crank in contact
with the piece F, and three times depresses the button of the switch N2. The
attendant at the "down" station answers by pressing again upon the button of
the switch N at this station, and the current then passing through the terminal F
of the switch M° sets the signalling apparatus to indicate that the line is blocked
against the "up" station. A similar operation will take place when the attendant
at the "down" station requires the line to be cleared, the direction being however
reversed; it will be observed that the attendant at the station from which a train
is to be sent must indicate that this may be done by simply depressing the button
of the pusher-switch N2 at the said station; the attendant at the station requiring
to send the train cannot set his signals to indicate that the line is clear, nor receive
the signal to that effect before having had the answer from the other station, and
before having properly set the switch M².
In some cases it may be inconvenient to light the lamps of the apparatus in the
evening; in that case, as illustrated in the diagram, Figure 7, the apparatus may
have a double arrangement with two red glasses (those that are section-lined in
the Drawing) and two white glasses (those to the left); the lower disc of the
swinging frame will be red and the upper disc white. In daytime four discs will
be seen simultaneously, but it will be understood that the line is clear when like
colors are seen in the same vertical line, otherwise the line will be blocked.
The upper discs or the lower ones are constantly illuminated, and therefore the
apparatus operates at night in the same manner as the apparatus described with
reference to Figure 1.
Having thus fully described the said Invention as communicated to me by my
foreign correspondents, and the manner of performing the same, I wish it under-
stood that I claim in electric signalling apparatus the following novel and
distinctive features, that is to say:-
°
First. The combination of parts whereby the whole of the traffic on a single line
of railway is protected and collisions are prevented.
Second. The utilization of the sudden impact of the pallets of the electro-
magnets in such a manner that an impulse is given to the swinging frame carrying
the discs to effect the uncovering of the red or of the white light, according to
whether the line is blocked or clear.

page_text: Third. The combination of a pusher switch or commutator and a two-way switch
or commutator, substantially as set forth, in such a manner that the corresponding
sets of apparatus at two stations may be maintained securely in their normal
positions, so that it will be impossible to set both to indicate " line-clear."
All substantially as set forth.
In witness whereof, I, the said William Robert Lake, have hereunto set my
hand and seal, this Sixth day of April, in the year of our Lord One
thousand eight hundred and eighty one.
W". ROBT. LAKE. (L.S.)