Improvements in Signalling Apparatus for Railways
Year: 1894

page_text: Date of Application, 4th Oct., 1894
Complete Specification Left, 3rd Aug., 1895-Accepted, 7th Sept., 1895
PROVISIONAL SPECIFICATION
Improvements in Signalling Apparatus for Railways
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 relates to nudible signalling apparatus specially applicable for
signalling on railways in foggy weather when ordinary signals are rendered obscure
or visible and consists essentially of bells or gongs operated electrically and
controlled by means of the approaching train and the ordinary signal levers
In one arrangement of apparatus constructed according to this invention a gong
18 mounted on a suitable frame and 13 souuded by means of a hammer attached to
an oscillating armature intermittently attracted by an electromagnet The electric
circuit is alternately closed and opened, by means of a counter weighted contact
maken operated by the armature, or by means of an oscillating and sealed cup
containing mercy into which the two ends of the insulated conductor are inserted
in such manner that when the said cup is tilted by the armature in one direction
the mercun y recedes from the conductor points and the cucuit is broken while,
when tilted in the reverse direction, the said points are immersed in the mercury
and the circuit thereby closed.
At any desired distance from the given signal a treadle arrangement is fixed
which, on the passage of a tram, causes the magnet chcutt to be closed for a
sufficient time to start the apparatus
In order to limit the time during which the signal gong is sounded, on the
passage of a train, a contact arrangement is placed in the electromagnet circuit
consisting of a ratchet or its equivalent operated by the oscillating armature so
that at each vibration the said wheel is advanced one step. Normally a contact
spring or finger rests upon an insulated part of the ratchet wheel or other suitable
connection, the circuit through the magnet being then broken, but on the closing
of the cucuit by the passage of the train the said ratchet wheel 15 advanced one
step which removes 'the aforesaid insulating apart from under the contact finger and
permits the closing of the ordinary magnet circuit to energize the magnet and
operate the gong armature in the ordinary manner until the contact finger is again
insulated and the apparatus occupies its normal position.
In a modified arrangement the gong is sounded by one or more hammers pivoted
to arms on a rotating spindle driven by a suitable electric motor, the number of
strokes being iegulated by a contact device similar to that herein before described
and the ratchet arrangement being preferably replaced by worm and pinion
gear
The lowering of the signal from its “danger” to “line clear” position closes
an electric circuit which operates a bell to indicate the same to the person in charge
of the tram.
Dated this 4th day of October 1894
WHEATLEY & MACKENZIE,
40 Chancery Lane, London, W.C., Agents.

page_text: 18a perspective elevation of the same.
A gong a mounted on a baseplate is sounded by means of a hammer having a
spring am d secured to the armature e intermittently attracted by the electro-
magnet and oscillating about a suspension pin g in a supporting bracket h secured
to the baseplate b of msulating material.
Connected to the armaturee is a lever bar i carrying a contact block I, adjustable
along its length, in order to vary the length of contact and fice to slide on the
contact bar in secured to the insulating plate n. A block of insulating material o
is inserted in the contact bai m so that when the block passes on to it from the
su face of the contact bat m the electric circunt through the coils of electro-
maguetis boken In the end of the lever bar is fixed a projecting pin p which,
when the matinee nears the end of its inward oscillation, passes under a trap
lever q which then falls into its normal position with its point in contact with the
plate, the return o-cillation of the amature e causing the pin to travel over
the surface of the said trap lever q. thereby inising the contact block clear of the
bai mand keeping the controlling circuit open until the said pin falls over the
hinged end of the tiap lever when, the contact block bad barm agam making
contact, the controlling circuit is again closed and the armature è attracted by the
magnet f.
"
• 1.
In order that the gong a may receive a definite predetermined number of beats
from the hammer c cach time the apparatus is operated a controlling and encuit
closing device is provided as follows:-
Mounted on a spindle or ai bor s working in a bracket & secured to the base b, of
insulating material, is a ratchet wheel which is engaged by a pawl comprising
the tooth adjustably mounted on the bar hinged to and operated by the
armature e On the same arbor is mounted a disc y carrying an arm and having
a segment of insulating material a inserted in its periphery On the said disc
rests the rubbing contact shoe of the lever changed to the insulated bracket d'
secured to the buse b.
:
.
Normally the shoe rests upon the segment a' of insulating material in the
discy and the am presses the cam lever et against the contact spring so that
on closing the circuit, by means of a switch or other ciremt closing device at g',
the current passes to terminal ', through coils of electromagnet insulated
bracket contact spring, cam lever e', terminal m' and back to battery. This closing
of the operating circuit by external means suffices to energise the magnet Eo as to
attract the armature e aud so produce the initial oscillation whereby the gong reccives
e beat, and the ratchet wheel v aud disc y are advanced one step, the segment a',

page_text: of insulating material, being carried beyond the shoe which is then in contact
with the metal dist. y, while the cam lever el, being no longer pressed by the aim
against the contact spring /1, breaks the electric circuit A weighted detent or
chek a prevents the backward motion of the ratchet wheel In this position of
the mechanism the contact block / rests upon the segment o of insulating material,
but the automatic return of the armature e cau es the pin p to travel over the tiap
lever 9 when the block falls upon the metal contact bat m which thus completes
the electric circuit from the battery through terminal A, coils, bracket d', contact
lever c', disc y, spindle, ratchet v, pawl w, bar, amature e, bar 4, block 1, bar m,
temal o aud battery B the magnet being energised and the armature being
attracted to effect a second beat of the hammer on the gong a
The operation is repeated automatically until the atehet has been rotated
through a complete evolution and the contact shoe again rests upon the
segment al of sulating material, the cncut being thereby bioken
The last step in the rotation of the ratchet brings the aim into engagement
with the cam lever el pressing it against the contact spring so that on again
closing the cremt at g' the cycle of operations is repeated
limits the
It will be obvious that the apparatus will continue in operation for an indefinite
period so long as the contact at 7 remains closed A stop block
oscillation of the armature e when attracted to the magnet
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 [
claim is
-
1 The combmation of parts constituting my improvements in signalling
apparatus arranged constructed and operating substantially as described in the
foregoing Specification and illustrated in the diawings hereunto annexed
2. The combination with the oscillating armature of an electiomagnet, of a
contact or circuit closing device comprising a lever bar connected to the said
armature and carrying an adjustable contact block adapted to slide along a contact
bar as the armature approaches its electromagnet, and a trap lever adapted to lift
the said block ont of contact with the said contact bar during the return
oscillation of the armature, the whole substantially as described and for the purpose
set forth
3 The combination of the lever bar and adjustable block with contact bar m
having insulated segment o substantially as described for the purpose set forth.
4 In a contact or circuit closing device the combination of a contact lever bar
having an adjustable contact block 1, with a trap lever 7 substantially as described
and for the purpose specified.
5 The combination of the adjustable pawl to a connected to the oscillating
amature e, ratchet wheel e, contact disc y having segment a¹ of insulating material,
and contact lever substantially as described
6. A encuit closing device comprising a contact spring f', a cam lever el
capable of being pressed into contact with the said spring and an aim z mounted
on the spindles and adapted to engage with the said cam lever so as to force it
nto contact with the spring f¹ substantially as described and for the purpose set.
forth.
Dated this 2nd day of August 1895.
WHEATLEY & MACKENZIE,
40 Chancery Lane, London, W C', Agents.