IMPROVEMENTS IN THE METHOD AND APPARATUS FOR PRODUCING AUDIBLE SIGNALS ON RAILWAYS BY ELECTRICITY
Year: 1881

page_text: LETTERS PATENT to Edward Tyer, of No. 4, Old Street, Finsbury, in the
County of Middlesex, for an Invention of "IMPROVEMENTS IN THE METHOD
AND APPARATUS FOR PRODUCING AUDIBLE SIGNALS ON RAILWAYS BY
ELECTRICITY."
PROVISIONAL SPECIFICATION left by the said Edward Tyer at the Office
of the Commissioners of Patents on the 3rd March 1881.
EDWARD TYER, of No, 4, Old Street, Finsbury, in the County of Middlesex.
"IMPROVEMENTS IN THE METHOD AND APPARATUS FOR PRODUCING AUDIBLE
SIGNALS ON RAILWAYS BY ELECTRICITY."
On railways it is usual to place in advance of a station or stopping place a distant
signal to inform engine drivers whether it is safe or not for their train to proceed,
this signal being worked from a cabin or signalling station at or near the stopping
place. When the signal is obscured by fog or otherwise it is necessary to provide
other means, such as detonating signals, to give an audible intimation to the engine
driver corresponding with that which would be visibly given by the ordinary
signal. My Invention relates to means for giving audible signals which may serve
in lieu of the usual signals when these are obscured, or which may be employed
along with the visible signals as additional means of securing the driver's attention.
For this purpose at the distant signal, or preferably at some distance in advance of
it, I mount a gong or bell having its hammer worked by the armature of an electro-
magnet, the coil of which is intermittently excited by electrical currents trans-
mitted from a battery. These electrical currents are intermitted by means of a
rotating commutator caused to revolve by clockwork, which clockwork is kept
wound up so as to be ready to start when required. For the purpose of starting it
an electrical contact apparatus is arranged at the side of the rail at a point some
distance in advance of the gong or bell, so that on a train passing this point it, by
depressing a trigger or by causing deflection of a rail, effects the required contact.
When contact is thus momentarily made by the train a polarised contact at the
gong or bell is made to close the circuit of an electromagnet at the clockwork,
which releases a detent, and the clockwork thereupon starts, moving the inter-
mitting commutator so that the gong or bell is caused to sound, beginning to sound
Price 8d1

page_text: before the train arrives at it, and continuing to sound while and after the train
passes it. When the clockwork has been in motion for a sufficient time, say, from
half to three quarters of a minute, it by its own movement replaces the detent so
as to stop itself, leaving all the electrical connections ready to bring the apparatus
again into action. The act of the clockwork in replacing the detent also by causing
a momentary reversal of current moves the polarised contact at the gong or bell,
and thereby breaks the circuit, which remains broken until the subsequent passage
of a train again closes the circuit. By the use of the polarised contact a single
wire is made to suffice for the working of the apparatus; when two wires are used
the polarised contact may be dispensed with.
In order to provide for this signalling apparatus not coming into action except
at times when the ordinary visible signal would be employed, I make one part of
the electrical connections dependant on the position of the ordinary signal lever, so
that unless it be moved to the position for putting the visible signal to danger
there is a breach in the electrical connections, and the audible signal apparatus
remains inoperative. In order to avoid the necessity for winding up the clockwork
as a separate operation it is of advantage to make the signal lever work a remontoir
apparatus, winding up the clockwork so as to make up for the amount of its
unwinding while the audible signal is in operation. The winding up may also be
effected by means of a ratchet worked by the spring armature of an electromagnet,
which is brought into circuit by the clockwork when it is to a certain extent
unwound, and excluded from the circuit when it has been sufficiently rewound.
The clockwork and its commutator may be dispensed with by adopting the
following arrangement:-I place near the bell or gong: a battery which, when
brought in circuit with the electromagnet, causes the hammer to reciprocate in the
usual way. In order to bring it into circuit I provide a relay, momentarily acted
on, as described, by the passage of a train over a point of the line so as to make
the contact necessary for bringing the electromagnet of the gong or bell in circuit
with its local battery. At a farther point of the line past the gong or bell I
provide another contact, which when momentarily acted on by the passage of a
train breaks the circuit previously established. Thus a train as it approaches the
the gong or bell makes the contact which starts it into action, and after passing the
gong or bell it causes its action to cease. Instead of placing the battery which
works the gong or bell near it it may be placed in the signal cabin, having its
opposite poles connected by two wires to a polarised commutator, which is acted
on by the train after it has passed the gong or bell.
In many cases it is convenient to indicate audibly that the distant signal is at
safety as well as to indicate that it is at danger. By duplicating some of the
electrical connections and employing two gongs or bells of different tones, say, a
bell of shrill tone to indicate safety and a gong of deep tone to indicate danger,
both signals can be audibly given in the manner above described. In this case the
signal lever in its position corresponding to safety makes a contact which, conspiring
with that produced by the passage of a train, brings the bell into operation, and in
its position corresponding to danger it makes a contact which also conspiring with
that produced by the passage of a train brings the gong into operation.
In sections of line where signal cabins are far apart it may be desirable to
inform engine drivers of their position with reference to the train that has preceded
them. This may be effected by providing at various parts of the line gongs or
bells with local batteries and relays, as already described, so that when a train is
approaching close to one of these gongs or bells it starts it into action, and does
not cause it to stop till it has attained some distance beyond it. The driver of a
succeeding train if he hears the gong or bell is thus apprised that the preceding
train is within a determinate distance in front of him.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Edward Tyer in the Great Seal Patent Office on the 1st
September 1881.
EDWARD TYER, of No. 4, Old Street, Finsbury, in the County of Middlesex.
"IMPROVEMENTS IN THE METHOD AND APPARATUS FOR PRODUCING AUDIBLE
SIGNALS ON RAILWAYS BY ELECTRICITY."
On railways it is usual to place in advance of a station or stopping place a
distant signal to inform engine drivers whether it is safe or not for their train to
proceed, this signal being worked from a cabin or signalling station at or near the
stopping place. When the signal is obscured by fog or otherwise it is necessary to
provide other means, such as detonating signals, to give an audible intimation to
the engine driver corresponding with that which would be visibly given by the
ordinary signal. My Invention relates to means for giving audible signals which
may serve in lieu of the usual signals when these are obscured, or which may be
employed along with the visible signals as additional means for securing the
driver's attention. For this purpose at the distant signal, or preferably at some
distance in advance of it, I mount a gong or bell having its hammer worked by the
armature of an electromagnet, the coil of which is intermittently excited by
electrical currents transmitted from a battery. These electrical currents are inter-
mitted by means of a rotating commutator caused to revolve by clockwork, which
clockwork is kept wound up so as to be ready to start when required. For the
purpose of starting it an electrical contact apparatus is arranged at the side of the
rail at a point some distance in advance of the gong or bell, so that on a train
passing this point it, by depressing a trigger, or by causing deflection of a rail,
effects the required contact. When contact is thus momentarily made by the train
a polarised contact at the gong or bell is made to close the circuit of an electro-
magnet at the clock work which releases a detent, and the clockwork thereupon
starts moving the intermitting commutator so that the gong or bell is caused to
sound, beginning to sound before the train arrives at it, and continuing to sound
while and after the train passes it. When the clockwork has been in motion for
a sufficient time, say, from half to three quarters of a minute, it by its own
movement replaces the detent so as to stop itself, leaving all the electrical con-
nections ready to bring the apparatus again into action. The act of the clockwork
in replacing the detent, also by causing a momentary reversal of current, moves
the polarised contact at the gong or bell, and thereby breaks the circuit, which
remains broken until the subsequent passage of a train again closes the circuit.
By the use of the polarised contact a single wire is made to suffice for the working
of the apparatus. When two wires are used the polarised contact may be dispensed
with.
In order to provide for this signalling apparatus not coming into action except
at times when the ordinary visible signal would be employed, I make one part of
the electrical connections dependent on the position of the ordinary signal lever,
so that unless it be moved to the position for putting the visible signal to danger
there is a breach in the electrical connections, and the audible signal apparatus
remains inoperative. In order to avoid the necessity for winding up the clockwork
as a separate operation it is of advantage to make the signal lever work a remontoir
apparatus, winding up the clockwork so as to make up for the amount of its
unwinding while the audible signal is in operation. The winding up may also
be effected by means of a ratchet worked by the spring armature of an electro-
magnet, which is brought into circuit by the clockwork when it is to a certain
extent unwound, and excluded from the circuit when it has been sufficiently
rewound.

page_text: The clockwork and its commutator may be dispensed with by adopting the
following arrangement:-I place near the bell or gong a battery which when
brought in circuit with the electromagnet causes the hammer to reciprocate in the
usual way.
In order to bring it into circuit I provide a relay momentarily acted
on, as described, by the passage of a train over a point of the line so as to make
the contact necessary for bringing the electromagnet of the gong or bell in circuit
with its local battery. At a farther point of the line past the gong or bell I provide
another contact which when momentarily acted on by the passage of a train breaks
the circuit previously established. Thus a train as it approaches the gong or bell
makes the contact which starts it into action, and after passing the gong or bell
it causes its action to cease. Instead of placing the battery which works the gong
or bell near it, it may be placed in the signal cabin having its opposite poles
connected by two wires to a polarised commutator which is acted on by the train
after it has passed the gong or bell.
In many cases it is convenient to indicate audibly that the distant signal is at
safety as well as to indicate that it is at danger. By duplicating some of the
electrical connections, and employing two gongs or bells of different tones, say,
a bell of shrill tone to indicate safety, and a gong of deep tone to indicate danger,
both signals can be audibly given in the manner above described. In this case the
signal lever in its position corresponding to safety makes a contact which, con-
spiring with that produced by the passage of a train, brings the bell into operation,
and in its position corresponding to danger it makes a contact which, also conspiring
with that produced by the passage of a train, brings the gong into operation.
- In sections of line where signal cabins are far apart it may be desirable to inform
engine drivers of their position with reference to the train that has preceded them.
This may be effected by providing at various parts of the line gongs or bells with
local batteries and relays, as already described, so that when a train is approaching
close to one of these gongs or bells it starts it into action, and does not cause it to
stop till it has attained some distance beyond it. The driver of a succeeding train
if he hears the gong or bell is thus apprised that the preceding train is within a
determinate distance in front of him.
<
The accompanying Drawings shew the construction of the several parts of the
apparatus which operate in conjunction, as above described. Fig. 1 shews one form
of electric contact apparatus, which can be fixed in a suitable position on the
railway, so that the passage of a train shall cause electrical contact to be made for
the purpose of transmitting a current to start the signalling apparatus. A is a
bracket clamped to the rail between two sleepers. On this bracket is fixed a
box B containing mercury, and a metal dise C with a number of pointed studs
projecting down from it is adjusted by screwing its stem through insulating
material in the cover of the box, so that the points of the studs are just clear from
the surface of the mercury. The stem of the disc C being connected to the line
wire L while the mercury in the box is in connection with "earth," as long as the
mercury is in repose there is no electrical connection between the line wire L and
earth," but when by the passage of a train over the part of the line where the
bracket A is fixed the mercury becomes agitated so as to touch the studs of the
disc C contact is made, connecting for the time the wire L to "earth." The box B
might obviously be insulated from the bracket, and connected to another branch
of the line wire, so that when a train passes the two branches of line wire would
be for a time connected. Fig. 2 shews an arrangement of contacts which I apply
to the ordinary signal lever, so that in one position it breaks and in its other
position makes electrical connection for signalling, as above described. The line
wire L is connected to an insulated bent spring F, which is clear from the arm of
the signalling lever in the one position, shewn by dotted lines in Fig. 2, but which
bearing against that arm when the lever is moved over makes connection between
the wire L and "earth." Fig. 3 is a front view of an ordinary telegraphic block
signalling instrument modified so as to indicate to the operator whether the gong
apparatus is in action or not, and to enable him to put it in action. For this

page_text: "
purpose an index.I has on its axis a short arm i, which passes through a hole in a
spring attached to the armature of an electro magnet M. While the gong
apparatus is not in action the electromagnet M, whose coils are in the circuit of
that apparatus, is inert, and the index I retains the position shewn, pointing to a
mark on a dial, such as ". gong silent." When the gong apparatus is in action the
electro-magnet M attracts its armature, and the spring / by its action on the arm i
causes the index I to move to the position I', pointing to a mark on the dial, such
as gong sounding." P is the plunger, employed in the usual way for block
signalling by pushing it in so as to act on suitable contact springs S behind it.
In addition to the usual springs for this purpose I employ a spring S¹ connected
to one D of two insulated plates D, D¹, the other D' being connected to the battery
employed for ordinary signalling. The signalman by inserting a metal pin d so as
to bring the two plates D, D', into metallic connection can then when he pushes in
his plunger P not only transmit the ordinary signal, but also by thus connecting
his battery through D¹, d, D, and S' with the gong apparatus bring it into action.
The clock work employed to keep the gong sounding for a determined time is
shewn by Figs. 4, 5, 6, 7, and 8. Fig. 4 is a front view, Fig. 5 a vertical section,
Figs. 6 and 7 are side views on the right and left respectively, and Fig. 8 is a plan.
A is the spring barrel and A¹ the fusee, on the axis of which I fix a tooth a
gearing with a segmental rack. On the axis of this rack is an index a', which
moves with the rack, one tooth for every revolution of the fusee, and which shews
on an external dial when the clock requires winding up. A spring pawl a² holds
the rack with sufficient friction to prevent it from moving, except by the action of
the fusee tooth a. From the fusee A¹ is driven by gearing a spindle B, having on
it two wipers b, b. From B is driven a spindle C, having on it a wheel C¹ with
two pins c projecting from its face. This wheel drives another spindle D, which
by worm gearing drives a flyer D¹. A bent lever E drawn by a spring e is held
in the position shewn in Fig. 5 by its long arm resting on a pin projecting from an
upright spring arm f extending from the armature F of an electro magnet M,
which armature is drawn away from the poles of the magnet by a spring f'.
While the lever E is thus supported its vertical arm catching under one of the
pins c keeps the wheel C¹ stationary, and thus prevents the clockwork from moving.
When however, in consequence of a current of electricity passing through the coils
of the electromagnet M, the armature F is attracted, withdrawing the support f,
then the lever E moves to the dotted position shewn in Fig. 5, withdrawing the
stop from the pin c, and thereupon the clockwork starts into movement. The
stopping of the clockwork after a certain amount of movement is effected in the
following manner:-On the axis E¹ of the lever E is fixed another bent lever E³,
the long arm of which works an index E³, shewing on an external dial in one
position that the gong is silent, and in its other position that the gong is sounding.
The short arm of the lever E2 is linked to a vertical rod, from which projects a
tooth E. As the clockwork moves, the spindle B in turning half a revolution
brings one of its wipers 6 under the tooth E, and raising that tooth and the rod
from which it projects causes the spindle E¹ to turn partly round, so that the
lever E has its long arm raised again to be above the stud on the arm f, and when
dropped rests upon that stud, and its shorter arm again catches one of the studs c
on the wheel C¹, so stopping the clockwork. The movement of the clockwork effects
electrical connections and disconnections in the following manner :-First, on a
rocking spindle G is fixed a commutating segment G¹, against the face of which
bear 4 insulated spring contacts g. When the clockwork is at rest these contacts
close the circuit of the line wire and earth, including the electromagnet M, so that
when a current is transmitted along the line wire the electromagnet is excited and
attracts its armature, thereby causing the clockwork to start, as above described.
When however the clockwork has moved so far that one of the wipers b engaging a
stud g¹ projecting from an arm of the commutator spindle G causes the commutating
segment to move up, the contacts made by the springs g are changed so that the
electromagnet M is cut out of circuit, and its armature F is lift free to be moved

page_text: away, as above described. This movement of the commutating segment G¹ also
causes a reverse current to be transmitted along the line wire, and this current
operating upon a polarised relay near the gong cuts the gong out of circuit. When the
wiper b escapes the stud.g¹, the commutator segment G' is by means of a spring g²
restored to its normal position, shewn in Fig. 4, making good again the circuits
ready for succeding action of the clockwork. One of these circuits includes two
spring contacts which bear against a commutating disc H fixed on the spindle D;
this disc having on its periphery segments of metal laid on and separated by
insulating material. As the spindle D revolves, these pieces of metal make
intermittent electrical connection between the two springs h, and each impulse thus
transmitted by acting on an electromagnet causes a stroke of the gong, as shewn
in Fig. 9, which is a front view of the gong apparatus. Here K is the electro-
magnet whose coils are in the circuit of the contacts h of the clockwork; K' is its
armature suspended by a spring K2, which is so set as to tend to withdraw the
armature from the poles. At the end of the armature rod is a hammer K³, which
every time the armature K¹ is attracted strikes the gong K4; Fig. 10 is a front
view of the polarised relay mentioned above as being interposed in the line wire
between the gong apparatus and the contact springs g of the clockwork. In this
relay a thin cylindrical soft iron armature N cut in halves is mounted on an axis
between the poles P, P, of a permanent magnet and the poles Q, Q, of an electro-
magnet whose coils. are in the circuit of the line wire, the cylindrical armature
being polarised by the presence of the permanent magnet. On the axis of the
armature is a segmental arm R, which in the normal condition of the relay is out of
contact with a spring r, but when a current of the usual sign is transmitted makes
contact therewith. When however there is a temporary reversal of current
produced by the movement of the segment commutator G¹, as above described,
then the arm R is caused to retreat from the contact 7, breaking the circuit until
the current is again reversed or intermitted.
Instead of the polarised relay, shewn in Fig. 10, another form of relay, shewn in
front view at Fig. 11 and in plan at Fig. 12, may be used in combination with the
gong apparatus shewn in Fig. 9, in which case the clockwork is dispensed with.
When this arrangement is adopted the armature K¹ of the gong apparatus is
provided with a make and break contact K³ so as to intermit its own action. The
relay shewn by Figs. 11 and 12 is of the following construction:-An electro-
magnet S having its coils in circuit with the line wire has an armature T drawn
by a spring t away from the poles of the magnet, in which position the upper part
of the armature carrying an insulated piece of metal U is separated from two
contact springs u, one of which is connected to a local battery, and the other to the
coil of the electromagnet K of the gong apparatus. When a train passing the
contact apparatus on the line completes circuit of the line wire, the electromagnet S
(Figs. 11 and 12) being excited attracts the armature T, and the piece of metal U
being thus pressed against the springs u, u, connects them electrically, so that a
current from the local battery excites the electromagnet K (Fig. 9), causing the
gong to sound. The armature T also makes two other contacts v, v, making
connection between the local battery and the line wire, and as thus T continues to
be attracted as long as a current passes along the line wire, the gong will go on
sounding until this current is interrupted, either by the signalman moving bis
signal lever, or his telegraphic signalling handle so as to break the circuit, or by
the passage of the train over a point of the line in advance of the audible signal, at
which point there is established a contact breaking apparatus. When in either of
those ways the line wire circuit is broken, the armature T (Figs. 11 and 12) is
retracted by its spring, and the contacts u, u, and v, v, being thus disconnected the
gong ceases to sound. It is to be understood that the coils of the electromagnet S
are wound with double wires, the one wire being in circuit with the line wire, and
the other wire with the local battery, so that the armature T is attracted in the
first instance by the passage of a current along the line wire caused by the passage
of a train, and being so attracted it closes the circuit of the local battery, thereby

page_text: causing the attraction to be maintained until the circuit be broken, as above
described.
Having thus described the nature of my said Invention, and in what manner the
same is to be performed, I claim,―
First. The herein described method of producing audible signals on railways by
causing a bell or gong to be sounded by electrical currents intermitted by
clock work, which is started into action by an electrical impulse transmitted by the
passage of a train over a point of the line in advance of the audible signal, and
which after a certain time of movement becomes automatically stopped, replacing
the electrical connections in condition for a subsequent action of like kind.
Second. The modified method herein described of producing audible signals on
railways by causing a bell or gong to be sounded by electrical currents from a local
battery, the circuit of which is closed by movement of a relay actuated by an
electrical current transmitted by the passage of a train over a point of the line in
advance of the audible signal, and the circuit of which is opened by the return
movement of the relay actuated by the cessation of the electrical current, caused
by the passage of the train over a farther point of the line or by the action of the
signalman.
Third. The clockwork for operating, as set forth in the first claim, constructed as
herein described with reference to Figs. 4, 5, 6, 7, and 8 of the Drawings.
Fourth. The combination of the relay and gong apparatus herein described with
reference to Figs. 9, 11, and 12 of the Drawings.
In witness whereof, I, the said Edward Tyer, have hereunto set my hand
and seal, this Twenty fourth day of August, in the year of our Lord
One thousand eight hundred and eighty one.
EDW. TYER. (L.S.)