Improvements in Signalling Apparatus.
Year: 1893

page_text: Date of Application, 23rd Feb., 1893
Complete Specification Left, 23rd Nov., 1893-Accepted, 10th Feb., 1894
PROVISIONAL SPECIFICATION.
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 or "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 at definite desired intervals of time, 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 a
vibrating armature which is caused by its electro-magnet to oscillate backwards
and forwards, is connected to a screen placed between the light and the glass lens
of a signal lamp and to which it imparts a corresponding oscillating motion so that
the light is alternately exposed and obscured by it, thus producing a continuous
series of intermittent exposures or flashes.
The oscillating screen may be suitably counterweighted to return it to its initial
position after being displaced, and a contact breaker, which may comprise an arm
making contact with a rocking lever or a vibrating arm dipping into mercury, or
any other suitable device, is attached or connected to the oscillating armature in
such manner that on the return of the screen to its initial position the electric.
circuit is completed through the magnet coils, the armature attracted, and the
screen operated through one oscillation; the return oscillation being performed by
gravity, by a spring or by other suitable means.
In the apparatus described in the Complete Specification of Patent No. 9695
of 1889 hereinbefore referred to, the clockwork mechanism is liable to stop in sucn
a position that the electric circuit is closed, thereby causing great waste of battery
power. To obviate this defect I attach a cranked contact arm directly to the
pendulum in such manner that, when quiescent, the contact point is elevated out of
its mercury cup and the circuit broken.
Dated this 23rd day of February 1893.
WHEATLEY & MACKENZIE,
40, Chancery Lane, London, W.C., Agents.
COMPLETE SPECIFICATION.
Improvements in Signalling Apparatus.
1, LEICESTER BRADNEY STEVENS, of Darlington Works, Southwark Bridge
Road, 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

page_text: "
"
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 at definite desired intervals of time
so as to produce a continuous series of flashes, and thereby render the signal more
distinctive than is possible in the case of lamps having a constant exposure
of flame.
In the accompanying six sheets of illustrative drawings,
Fig. 1 represents a sectional elevation of one arrangement of signalling lamp
constructed according to this invention.
Fig. 2 represents a vertical transverse sectional elevation.
Fig. 3 is an inverted plan of the same and
Fig. 4 is an end elevation of the circuit breaking device.
Fig. 5 is a vertical section of a modified arrangement of signalling lamp with
rotary screen, and
Fig. 6 is a transverse section of the same.
Fig. 7 is a sectional elevation of an indicator operated synchronously with the
flashing screen, and Fig. 8 is a back elevation of the same with the back cover
removed.
Fig. 9 is an elevation of a modified arrangement of automatic electric circuit
controlling device to replace that shown in Figs. 5 and 6.
Fig. 10 is a plan and Fig. 11 is an end elevation of the same...
Figs. 12 and 13 are sectional elevations of a further modified arrangement of
lamp.
1
Referring to the apparatus shown in Figures 1 to 4 inclusive of the drawings:-
An ordinary signal lamp casing a with lenses b and c is provided with a movable
partition d sliding in the guides ee and having a hole f opposite the lens b so that
the area of the light passing through it from the burner g of the lamp his circum-
scribed. To the bottom of the lamp casing a is secured a plate i of insulating
material carrying an electromagnet j between the polar extensions of which
works an armature m mounted on its spindle axis n working in insulated bearing
brackets op and carrying at one end a counterweighted lever q secured to a
screen r, whilst on the other end of the said spindle is mounted a tappet lever
which when the armature m is oscillated engages with a curved double armed
levert pivoted on the pin v about which it is caused to oscillate, each such oscillation
causing a conductor w attached to it to alternately dip into and withdraw from a
mercurial contact cup and thereby make and break a controlling electric circuit.
Secured by the plate y is an insulated spring contact plate z which when the lamp h
is inserted, is pressed by it through the button a a into contact with the contact
plate ab so as to complete the electric circuit, the removal of the lamp allowing it
to again free itself of the plate ab and open the circuit.
Normally the screen occupies the position shown in dotted lines, when the
electric circuit passes from the generator through the insulated terminal a c,
plate a d, mercurial contact x, conductor w, lever t, plate a e, coils of electro-
magnet j, contact plates a b, z, and terminal af to the opposite pole of the
generator, the electromagnet j being thereby energized and the armature attractedi
and causing the screen lever q to be oscillated so as to place the screen over the
hole and thereby obscure the light, the oscillation of the lever 9 causing the
mercurial contact between the mercury and conductor to be broken and consequently
the electric circuit also; the screen ŕ then falls to its initial position the circuit
being again closed and the oscillation of the screen r being repeated indefinitely.
A stop a g secured to the plate d prevents the momentum acquired by the screen r
when oscillated, from projecting it beyond the required limit.
In the modified arrangement of signalling lamp shown in Figs. 5 and 6 the
oscillating screen r is replaced by a rotary disc operated by a suitable electromotor,

page_text: the electric circuit being automatically closed by the heat of the burner. A plate d
sliding in guides e is provided with a hole for admitting the light from the burner
to the lens 6 as in the arrangement herein before described, and has mounted on it
in front of the hole fa rotary disc screen a h with a hole corresponding to the
hole fin plate d. The disc is rotated by means of a small electromotor whose
armature is mounted on the disc spindle a i and works between the poles al of an
inclined field magnet a m. The field magnet circuit is controlled by a contact
maker comprising a lever an whose point is caused to make contact with the
insulated contact a o twice in each revolution of the armature. a p by means of a
double lobed cam aq on the armature spindle a i. The removal of the metal from
the disc a h to form the hole causes the said disc when at rest to occupy the position
shown, the armature a p then occupying a position relatively to the magnet most
favourable to starting, and the contacts ao an being closed. On the upper part of
the plate d are secured insulated plates ar as carrying spring contact plates at a v
which when the cover aw of the lamp is closed, make contact with corresponding
insulated contact plates a x ay secured to a crossplate az on the cover a w.
On the upper part of the lamp cover is secured a bridge block of insulating
material to which are secured two conductor plates ba bb from which depend two
compound conductor plates be bd each comprising two plates of different metal
having different rates of expansion under the action of a rise in temperature, for
example, the outer plates may be of copper and the inner ones of iron so that when
the lighted lamp h is placed in the casing and the temperature of the plates bc bd
raised the unequal expansion of the component plates of the compound plates causes
them to approach each other, the platinum points making contact and thereby
automatically completing the electric circuit.
The electric current is led from one pole of the generator through terminals be
motor frame plate bf contact lever an contact a o field magnets am terminal bg
plate ar contact spring at contact plate a a contact plates ba, bc, bd, bb, ay, av, a s
terminals bh be and to the opposite pole of the generator.
In order that the working of the apparatus may be indicated to the signalman in
his cabin an indicator located in the cabin is placed in the electric circuit operating
the lamp and is caused to act synchronously with the screen in the signal lamp.
Referring to Figs. 7 and 8 an armature bi mounted on the spindle bl is attracted
to the core of the electromagnet b m on the passage of an electric current through
its coils. On the spindle bl is also mounted a pointer bn to indicate the motion of
the armature and also a hammer bo which, at each oscillation, strikes the gong b p
and thereby produces an audible signal. The conductor from one pole of the
electric generator is connected to the terminals bq, the line being completed
through the electromagnet bm. It will be readily understood that should the
flashing apparatus at the lamp cease to act from any cause, the armature bi would
cease to oscillate, the cessation of the ringing of gong bp indicating the stoppage
to the signalman at once.
In the modified arrangement of automatic circuit controlling device shown in
Figs. 9, 10 and 11 the two depending compound plates shown in Figs. 5 and 6 are
replaced by a single compound plate br. In this case the indicator shown in Figs. 7
and 8 is also dispensed with, an electric bell being substituted therefor, which,
when the lamp is connected to its generator and alight, is inoperative but which
when the lamp is out or giving a light of less brilliancy than that prearranged, is
caused to ring and so notify the fact to the signalman in his cabin.
Two bars bs bt are passed horizontally through and secured to the cover a w of
the lamp casing and insulated therefrom by nonconducting plates.
A central compound plate br composed of two dissimilar metals having different
rates of expansion under variation of temperature is secured to the bars bs bt and
insulated therefrom by the insulating blocks bv bw any change of temperature
causing the free end to approach to or recede from the adjustable contact screw b.r
secured in the plate by connected to the bar bs by the insulating plate bz.
When the temperature in the lamp falls below a predetermined height the plate br

page_text: recedes from the contact screw ba the contact between them being broken and
contact being then made between the plate br and the spring ca secured to the
bar bt, the interval between the breaking of the one contact and making the other
being regulated by a wire cb which presses against the spring ea and is secured to
a plate cc capable of adjustment by means of the slot cd and screw ce as will be
readily understood.
The terminal cf is connected to the plate brand to one pole of the electric
generator while the terminals by cg are connected to the other pole, the circuit
through the flashing apparatus being automatically closed, when a sufficient
temperature is attained in the lamp by making contact between the plate br
and screw bæ. When however the temperature in the lamp falls below the
predetermined height the contact between the screw bx and plate br is broken
and that between the spring ca and plate br made, which closes an electric circuit
through terminals cf and cg and through an electric bell in the signal cabin thus
notifying to the signalman in charge that the lamp is not in proper working order.
Figs. 12 and 13 illustrate a lamp somewhat similar to that shown in Figs. 5
and 6; but instead of the disc a rotating, it is caused to oscillate. In this case a
contact arm ch, secured to the axis ai carrying the armature ap and disc ah,
makes contact at each oscillation with a contact spring ci through which the
electric motor circuit is completed. The disc a h is counterweighted and so tends
to return to its initial position after each oscillation by the motor, the angle of
oscillation being limited by stops cl and cm on the disc and plate d respectively
as will be readily understood.
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. In signal lamps: the employment of a screen operated by an electromotor
automatically controlled to alternately expose and obscure the flame of the burner
and thereby produce a succession of flashing signals, the whole arranged con-
structed and operating substantially as described with reference to Figs. 1 to 4 of
the drawings.
2. An oscillating disc screen mounted on the spindle n in combination with the
armature m electromagnets j arms curved lever t'and mercurial contact maker wa
substantially as described.
3. In a signal lamp; an oscillating disc screen operated by an electromotor as
described, in combination with a movable partition plate sliding in guides in the
lamp casing and having a hole through which the light passes from the burner to
the lamp lens substantially as described.
4. In a signal lamp: a spring contact plate automatically operated by the
insertion of the burner so as to close an electric motor circuit substantially as
described.
5. In a signal lamp for producing flashing signals a screen disc rotating before a
movable partition plate in combination with an electromotor for actuating the same
substantially as described.
6. In a flashing signal lamp; the combination with a moving screen, actuated
by an electromotor, of two depending compound contact plates, each composed of
two metals having dissimilar ratios of expansion substantially as described and for
the purpose set forth.
7. In a flashing signal lamp, automatically closing the electric circuit when
closing the cover of the lamp by means of contact plates arranged substantially as
described.
8. The arrangement and construction of signal lamps substantially as described
with reference to Figs. 5 and 6 of the drawings.
9. In a flashing signal lamp; the combination with a moving screen, actuated
by an electromotor, of an indicator placed in the motor circuit and comprising an
armature mounted on an arbor, an electromagnet for operating the same, a pointer

page_text: for visibly indicating the motion of said armature and a hammer which, at each
oscillation of the said armature, strikes a gong and thereby gives an audible signal,
all substantially as described.
10. In a flashing signal lamp; the combination with a moving screen, actuated
by an electromotor, of an automatic circuit controlling device operated by the
heat from the lamp burner and comprising a compound contact plate formed of
dissimilar metals and making contact to close an electric circuit through the
flashing apparatus when the lamp is burning with sufficient brilliancy or through
a bell when the light of the lamp is out or low to notify the same to the signalman
or other officer in charge substantially as described.
11. In a flashing signal lamp; the combination with a moving screen actuated
by an electromotor of an automatic circuit controlling device operated by variation
of temperature comprising a compound contact plate br, bars bs bt, adjustable
contact a spring contact plate ca and adjustable regulating pin substantially as
described.
12. In a signal lamp for producing flashing signals: an oscillating disc operated
by an electric motor in combination with a contact arm and contact spring arranged
and constructed substantially as described with reference to Figs. 12 and 13 of the
drawings.
Dated this 23rd day of November 1893.
WHEATLEY & MACKENZIE,
40, Chancery Lane, London, W.C., Agents.