Improvements in Signalling Apparatus.
Year: 1894

page_text: Improvements in Signalling Apparatus.
I LEICESTER BRADNEY STEVENS, of Darlington Works, Southwark Bridge
Road, in the County of Surrey, Engineer, do hereby declare the nature of this
invention to be as follows:
This invention for improvements in signalling apparatus relates to apparatus of
the class described in the Specification of Letters Patent No. 9695 of 1889, for
producing distinctive visible signals by night and is especially applicable for the
signal lamps used on railways where it is of importance to clearly distinguish the
"distant" from the "home" and "starting" signals, and has for its object to
construct an apparatus to be applied to, a signal lamp which shall automatically
and alternately expose and obscure the light so as to produce a continuous series
of intermittent flashes and thereby render the signal more distinctive than is
possible in the case of lamps having a constant exposure of flame.
In one arrangement of apparatus constructed according to this invention an
electromagnet when energized, attracts its armature which engages with an arm
connected to an oscillating screen which is thereby projected between the flame
and the lens of a signal lamp so as to obscure the light. The screen returns to its
initial position automatically and in so doing completes the electric circuit through
the magnet coils, the operation being repeated indefinitely, and the lamp flame
being thereby alternately, obscured and exposed thus producing a regular succession
of flashes.
A thermo-electric switch is provided in the signal lamp and connected to a gong
in the signal cabin to indicate whether the light is in or out, and the position of
the semaphore signal arm is also indicated in the cabin by means of a suitable
repeator electrically connected to a switch operated by the said arm:
Dated: this 28th day of September 1894.
WHEATLEY & MACKENZIE,
40 Chancery Lane, London, W.C., Agents.
Improvements in Signalling Apparatus.
I, LEICESTER BRADNEY STEVENS, of Darlington Works, Southwark Bridge
Rond, in the County of Surrey, Engineer, 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 :-
This invention for improvements in signalling apparatus relates to apparatus of
the class described in the Specification of Letters Patent No. 9695 of 1889, for
producing distinctive visible signals by night, and is especially applicable for 'the
signal lamps used on inilways, where it is of importance to clearly distinguish the
"distant" from the ❝ home
61
or starting" signal, and has for its object to
construct an apparatus to be applied to a signal lamp which shall automatically
aud alternately expose and obscure the light so as to produce a continuous series of
"
;

page_text: intermittent finsher, and thereby render the signal more distinctive than is possible
in the case of lamps having a constant exposure of flame.
In the accompanying two sheets of illustrative drawings:
Fig. is a vertical section of a signal lamp constructed according to this
invention.
Fig: 2 is an elevation of the flashing mechanism.
Fig. 3 is an elevation of a thermal switch by means of which an indicator to
indicate at a distance froin the lamp whether the flame is in or out, and also the
flashing mechanism, is automatically controlled.
Fig. 4 is un elevation of an indicator which shows the position of the signal and
Fig. 5 is a diagram of the electrical connections of the system.
A plate a held in the lamp casing bin guides, or otherwise secured, has a
circular hole c whose axis when in position for the transmission of light, coincides
with the axis of the lens d; whilst mounted on a piñ or arbor e secured to the said
plate; is a disc having a hole c which also, in one position; coincides with the hole
in the plate a: Mounted on the arbor e is a crank which is engaged by the arm
of the hinged armature of the electromagnet j. Cushioning springs Im limit the
travel of the armature i at each vibration and give it an initial returning impulse.
A spring contact plate n connected through the insulated plate o with the
terminal P makes contact with the crank g. One end of the magnet coil is
connected to the insulated terminal while the other end is connected to the bar f':
It will thus be seen that so long as the arms g and h are in contact, a current
passes through the magnet coils and the armature i is attracted and operates the
crank g causing the disc to rotate until the stops st strike each other when, the
electric circuit being broken by the breaking of the contact between the arms
and h, it returns to its initial position by the action of gravity and the circuit is
again closed, the operation being repeated indefinitely.
g
In order that the position of the lamp may be determined when the openings c
in the disc fand plate a are not coincident the light is not completely extinguished,
a small hole being provided which, when the diso is about one extreme of its
oscillation, is opposite the lens, by which means a small light sufficient to identify
its position, but not sufficient to produce a flash, is transmitted. Instead of the
hole va circular slit of suitable length may be employed.
In order that the signal operator in a sigual cabin at a distance may readily
ascertain whether the light in the lamp is in or out, an indicator is provided,
automatically controlled by means of a thermo-electric switch placed inside the
lamp and operated by the heat from the lamp flame.
Referring to Figs: 1 and 3 a perforated base w has mounted on it two compound
insulated contact plates y each comprising two plates of dissimilar metals having
different rates of expansion under equal changes of temperature, so that under a
temperature equal to that obtaining in the lamp when alight they make contact
with the screw contact points a¹ in the brackets b' ' on the insulating block d,
the said plates and brackets being connected to terminals e f g h On the
extinction of the lamp flame which is placed, in the centre of the casing a the
temperature of the plates y is reduced and the contact with points z a' broken.
The indicator (Fig. 5) comprises an electro-magnet whose armature Binged
at forms one arm of a lever n connected through level and spring
connecting wire o' to a lever p' carrying a disc q' on which the words "in" and
are printed.
out
When the armature jis attracted, the disc q' is raised and exhibits through a
hole in the casing & the word "in" the said armature at other times making
contact with the contact screw t¹ and the disc q' exhibiting the word "out
be readily understood.
12
as will
A semaphore arm having a crank arm w is operated by an arm on the
balanced armature y pivolted at 2', on the passage of a current through the electro-
magnet a² the cessation of the current permitting the armature to be raised and
the semaphore arm to fall.

page_text: Referring to Fig. 5, which shows a diagram of the electrical connections, the
electrodes of the battery A are connected to the terminal r of the flashing maguet
coils and to the terminal e' of the compound plate a of the thermal 'switch.
respectively the circuit being completed through the contact and plate and
flashing coils and the flashing mechanism being operated indefinitely so long as the
lamp is alight, but the circuit being broken at the contact z when the temperature.
is lowered on the lamp going out from any cause.
A battery B serves to operate the indicator, one end being connected to earth E.
while the opposite end and an intermediate cell are connected to the contact plate y
and the contact a' respectively, the circuit being completed through the contact
lever, contact 3, indicator magnet coils a' i and through earth. When the signal
lamp is alight and the arm d' up so that the contacts a¹ are closed, a current of
the whole battery power passes through the line and operates the arm &¹ and disc
of the indicator, the magnet & attracting the armature j' and breaking the contact
at t. When the light in the lamp goes out the contact at a' is broken and only a
part of the battery is in action the current being only sufficient to cause the
magnet a to operate the arm v while, owing to that part of the current which
passes through the magnet coils a being allowed to run direct to earth, the
magnet is not sufficiently energized by the remaining current to attract the
armature which therefore rests on the contact sorew the disc q' exhibiting.
66
the word out,'
"
21
The contact of the armature
through a gong es which gives an
light in the signal lamp.
The lowering of the signal arm
main circuit through coil a² when
corresponding position.
and contact screw t¹ closes an electric circuit
audible signal to indicate the extinction of the
displaces the contact lever & and breaks the
the arm of the indicator also falls into a
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 :-
¦—
1. The combination of parts constituting my improvements in signalling
apparatus the whole arranged constructed and operating substantially as described
in the foregoing Specification and illustrated in the drawings hereunto annexed.
2. In a signal lamp, a flashing device comprising an oscillating disc having
apertures for the passage of the light, in combination with an actuating electro-
magnet the whole substantially as described with reference to Figs. 1 and 2 of the
drawings and for the purpose set forth.
3. The combination with the actuating magnet of a flashing signal lamp of an.
armature provided with cushioning springs Im substantially as described.
4. In a flashing signal lamp, the combination with an oscillating discf having an
aperture e for producing the flash, of a secondary aperture for maintaining a
reduced light during the intervals between the flashing exposures of the light
substantially as described.
5. In a flashing signal lamp the combination with a perforated oscillating flashing
disc mounted on arbor e and carrying crank arms of contact spring n making
contact with the said crank arm and connected to terminal p substantially as
described.
6. The arrangement and construction of thermo-electric switch, substantially as
described with reference to Figs. 1 and 3 of the drawings.
7. The construction of indicator for indicating whether a signal lamp is alight
or not comprising a movable disc connected to the armature of an electro-magnet
controlled by a thermal switch in the lamp substantially as described.
8. An indicating device for indicating the position of a signal arm at a distance
comprising an arm operated by an electromagnet the energizing current of which
is controlled by the signal arm substantially as described.
9. An indicator for indicating whether a signal lamp at a distance is alight or

page_text: not and the position of the signal arm, the whole arranged constructed and
operating substantially as described with reference to Fig. 4 of the drawings.
Dated this 29th day of July 1895.
WHEATLEY & MACKENZIE,
40 Chancery Lane, London, W.C., Agents.