Year: 1899

page_text: I, WILLIAM EDWARD LANGDON, Electrical Engineer, Midland Railway, Derby,
do hereby declare the nature of this invention to be as follows:-
In railway signals. In an improved form of electrically actuated signal for
the guidance and control of railway traffic.
Within a fixed rectangular oblong case, glazed front and back, I provide
a rectangular frame capable of occupying the space covered by the glass front,
which frame I cover with, or within which I fix a suitably coloured-preferably
red semi-transparent material. This frame I arrange to work upon pivots, so
that it may, when in one position, occupy the glazed front of the case and thereby
presents a red or "danger" signal; and so that when in a position at right angles,
or thereabout, to this position it shall leave the glazed portion of the fixed case
unobstructed, thereby presenting a "line clear" signal.
"
66
This pivoted frame which forms the coloured signal, I arrange so that it shall
be moved in one direction-for the danger or line clear" signal, but preferably
the former by gravity, or by a spring; and for the production of the other, or
line clear" signal, by the aid of electricity.
For the purpose of rendering the signal visible at night I arrange a lamp in
connection with the fixed rectangular case, so that the light therefrom shall fill
the interior of the case, and thus, when the pivoted frame is arranged across the
glazed portion of the case, present a red, or danger, signal, and when in the
alternate position leave the enclosed space illuminated by the white light from
the lamp, thereby indicating "line clear."
And with a view to record, or indicate to the signalman by whom the signal
may be operated, the position in which it stands, I apply such electrical contacts
to the pivoted rectangular frame as shall, in conjunction with an electric battery
and suitable instrument, and the necessary wire between the signal post and the
signal box, indicate whether the signal is in the danger, or line clear"
position.
66
The movement of the pivoted frame which forms the danger signal I regulate
by means of a switch fixed in the signal box, in conjunction with a battery and
wire communicating therewith, or by a treadle, or other form of circuit maker,
in connection with the railway metals.
Dated this 22nd day of July 1899.

page_text: •
1, WILLIAM EDWARD LANGDON, Electrical Engineer, Midland Railway, Derby,
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 follow-
ing statement:-
In railway signals: an improved form of electrically actuated signal for the
guidance and control of railway traffic.
With a fixed rectangular oblong case, with glazed front and partially glazed
back, I provide a rectangular frame capable of occupying the space covered by
the glass front, which frame I cover with, or within which I fix a suitably coloured
-preferably red-semi-transparent material. This frame I arrange to work upon
pivots so that it may, when in one position, occupy the glazed front of the case
and thereby present a red or danger" signal, and so that when in a position
at right angles to this position, or thereabout, it shall leave the glazed portion
of the fixed case unobstructed, thereby presenting a "line clear" signal.
"
This pivoted frame, which forms the coloured signal, I arrange so that it shall
be moved in one direction forming the danger or, line clear signal, but preferably
the former, by gravity or by a spring; and for the production of the other, or
line clear" signal, by the aid of electricity.
..
For the purpose of rendering the signal visible at night I arrange a lamp in
connection with the fixed rectangular case so that the light therefrom shall fill
the interior of the case, and thus, when the pivoted frame is arranged across the
glazed portion of the case, present a red, or danger signal, and when in the
alternate position leave the enclosed space illuminated by the white light from
the lamp, thereby indicating line clear."
The movement of the pivoted frame which forms the danger signal I regulate
by means of a switch fixed in the signal box, in conjunction with a battery and
wire communicating therewith, or by a treadle, or other form of circuit maker,
in connection with the railway metals.
And with a view to record, or indicate to the signalman by whom the signal
may be operated, the position in which it stands, I apply such electrical contacts
to the pivoted rectangular frame as shall, in conjunction with an electric battery
and suitable instrument, and the necessary wire between the signal post and the
signal box, indicate whether the signal is in the danger or line clear"
position.
A, Figs. 1, 2, 3 and 4, is a rectangular oblong case having a glass front as
shown at C, Fig. 3, and a partially glazed back, preferably as shewn at F Fig. 4.
Fig. 1 is an interior view of the case; Fig. 2 a cross section of the same at X:
Fig. 3 an external front view, and Fig. 4 an external back view of the signal.
The interior of this case is painted white or otherwise as desired.
This
B is a rectangular frame capable of occupying or covering the glass front. C,
which frame I cover with a semi-transparent, preferably red, material.
frame is pivoted at / so that it may be free to fall by gravity to the vertical
position shewn by the full lines in Figs. 1 and 2, in which position it occupies
the glazed front of the case A, as shewn by the shaded portion C, Fig. 3, and is
also observable on the reverse side of the case at F.
With the object of counteracting to such extent as may be desired the tendency
of the frame B to assume the vertical position, and to enable it to assume a posi-
tion 90 degrees or thereabout from the vertical, as shown by the dotted lines g,
Fig. 2, I attach to the frame B a counterweight e, Figs. 1 and 2, together with

page_text: crank or lever h which I connect to the armature 1 of an electromag
lenoid K by the rod h. The armature I is pivoted at i.
Now on the electromagnet I becoming energized by an electric current passing
rough the coils, the armature I will be attracted towards the pole pieces and
On being thus attracted the
ill assume the dotted position shewn in Fig. 2.
od will be lifted up and the crank h, together with the frame B, will be raised
o the dotted position shewn at g g'.
Thus when no current is passing through the coils of the electromagnet K,
he frame B will by gravity occupy a vertical position presenting a red front,
or danger signal, and when the electromagnet is energized and the armature
brought into the dotted position, the frame B will be raised to the horizontal
position and the glass front, being no longer obscured by it, will present an open
or blank space exposing the white interior of the case A thereby expressing a
white, or fine clear, signal.
The counterweight may be replaced by a spring, and if necessary a spring may
be employed to withdraw the armature I from the electromagnet and thus accen-
tuate the vertical position of B.
L is a lamp so arranged that its rays shall be thrown through the glass parti-
tion m along the interior of the case containing the signal. M is a reflector.
This reflector may be supplemented, where necessary, by other reflectors arranged
within the case so as to effect an equable distribution of light throughout its
length.
Figs. 5 and 6 illustrate, diagrammatically, the circuit arrangements for opera-
ting the signal direct from a signal box, or in connection with the railway metals.
The
In Fig. 5, K represents the electro-magnet (Figs. 1 and 2), L the line wire
connecting the same with a switch H, and battery X.at the signal box.
circuit forms connection with "earth," or a return wire, at E. On closing the
switch H the circuit will be formed and a current will pass from X to K; the
electro-magnet will be energized, and the armature 1 (Fig. 2) will be lifted, and
off" position,
with it the red screen B, and will be retained in the horizontal, or
line clear signal.
so long as this condition is maintained, thereby presenting a
On the switch H being opened, the circuit will be broken and the red screen B
will fall to the vertical position, presenting a red, or
and 2), A is a steel core relay,
In Fig. 6K is the electro-magnet (Figs.
5 doubly wound, in the same direction, of which a, a are its steel cores, or poles,
the relay tongue, and c c¹ contact studs or stops; e is a battery, da contact
maker formed by, or connected with, the railway metals, each in circuit with
one winding of the relay coils.
danger" signal.
"
The other winding of the relay is in circuit with a line wire L¹, switch H¹,
(and battery X at S, which may be the signal box or other position.
15
The electro-magnet K (Figs. 1 and 2) is in circuit with the contact stud c of A,
and when the relay tongue b.is in contact with that stud, with the line wire L,
Each circuit connects at its termination with
the switch H and battery X.
" earth."
On the switch & being closed a current will flow through the cores a a¹, and b
will be attracted towards the stud e¹. The cores a a¹, being steel, will retain the
polarity imparted to them by the direction of this current, and the relay tongue
will be retained in the position indicated until removed from it by a current pass-
ing around the magnet cores in the reverse direction. So long as the relay
50 tongue is in this position, K will be disconnected from L and consequently wil
not be energized, and the red or danger signal will be produced at A, Fig. 1.
To reverse this signal it is necessary that should be in contact with the
A current will then pass from X
stud c.
This is effected by the switch H¹.
along L, through the second winding of A (Fig. 6) to earth. This current i
55 of a reverse polarity to that which emanates from e, and the tongue will, b
its aid, pass from the stud d¹ to stud c, and thus complete the circuit between
and L. In order, however, to place the signal in the line clear position, th

page_text: switch H has to be closed. A current will now flow from X through H, line L,
relay tongue b, contact stude, through K which will become energized, and the
danger signal will be removed from the glass front of A, Fig. 1. The diagram
shows but one battery at X. Of course independent batteries may be used. The
switches H H may be operated by hand or automatically by a signal lever or
other suitable arrangement.
.
A train
In order to further illustrate this operation, assume that the signal is in the
line clear position, i.c., that a current is flowing from X at S, along L, b, c, and
through K. K is now holding the danger signal off, and, the interior of the
signal case being white, it presents a white signal indicating line clear.
passes, and, in doing so, operates d, thereby is removed from e to e¹. K is no
longer under the influence of the battery X, and the danger signal is produced.
This remains so until the train arrives at S, when the switches H and H are
automatically, or otherwise, closed, and the line clear signal restored.
When it is required to repeat to an adjoining signal box, or other point, the
position of the signal frame B (Figs. 1 and 2), or similarly operated signals, I
attach to the frame B a contact lever O, Fig. 7, so that, when B is in a vertical
position, the said lever shall form contact with a spring p, and when B is in
the horizontal position, it shall form contact with p. I connect these parts as
diagrammatically shown in Fig. 8, where is the contact lever, p p contact
springs, B the signal screen, batteries, to earth at E, L line wire, and I an
ordinary electric repeater instrument having an indicator, carrying the words
OFF and ON, which instrument is also connected to earth. On O forming
contact with a positive current will flow to line and cause the indication "signal
ON" to appear.
On O passing to p¹, a negative current will flow and the indica-
tion signal OFF" will then be presented. Should O fail to make contact with
either stud the instrument will present an incomplete indication, indicating that
the signal is neither on nor off.
"
Having now particularly described and ascertained the nature of my said
invention, and in what manner the same is to be performed, I declare that what
I claim is-
First. An electrically operated signal substantially as illustrated and described.
Second. The operation of the same substantially as illustrated and described
under Figs. 5 and 6.
Third. Electrically repeating the position of the same or similarly electrically
worked signals substantially as set forth in the text and diagrams Figs. 7 and 8.
Dated this 20th day of April 1900.
WILLIAM EDWD. LANGDON.