Improvements in Electrical Signalling Apparatus for Railways.
Year: 1887

page_text: Date of Application, 10th June, 1887
Complete Left, 1st Dec., 1887
Complete Accepted, 20th Jan., 1888
PROVISIONAL SPECIFICATION.
Improvements in Electrical Signalling Apparatus for Railways.
I WILLIAM EDWARD LANGDON, Electrical Engineer, Midland Railway Derby, in
the County of Derby do hereby declare the nature of this invention to be as
follows:-
In the combination of certain parts of Telephonic Apparatus employed for the
purpose of conveying speech or other signals from one point to another with certain
parts of electrical bells employed for Block signalling purposes on railways in such a
imanner that the combined instrument or instruments may be employed upon the same
wire which is used for the Block Signalling Bell.
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In order to effect this I wind the coils of the Electro-magnet of the Bell instrument
with a <<
secondary wire, and I employ it when using the telephone communication
in place of the Induction" coil specially provided for that purpose in ordinary
Telephone instruments for producing the induced current and I arrange the
connections between these parts and other parts of the portions of the two instruments
in such a manner that when the Telephone is in a certain position-say its position of
rest the secondary circuit of the said electro-magnet shall be interrupted and the
main line wire shall be placed in circuit with the primary wire and such other parts
of the bell signalling instrument as shall enable signalling by the bell alone to he
conducted in the ordinary course and that when the telephone is removed from the
said position of rest the " primary coil shall be placed in circuit with the local
battery and telephone transmitter portion of the apparatus and the "secondary" wire
connected through to the main line wire and earth so that the block signalling bell
may be cut out of circuit and telephonic communication carried on upon the same
wire as that employed for the block bell signalling.
"
Now in illustration let it be assumed that signal box A and signal box B are
provided with instruments combined as here indicated and that a preconcerted signal
of a certain number of beats upon the bell has been arranged as the "Telephone
signal on rendering which the signalmen at either box shall understand they are to
attend to the telephone. Assume that A renders this signal to B. Backnowledges
it and both thereou remove their telephones from their position of rest. The removal
DOJ

page_text: of the telephone from its position of rest brings into play a switch so constructed
that it interrupts the communication with the hell signalling instrument, and completes
that with the telephone. The signalmen will then communicate what they have to say
and on restoring their telephones to their position of rest the main line wire between
A and B will be cut off from the telephonic apparatus and restored in connection
with that forming the bell communication.
Dated this Eighth day of June, One thousand eight hundred and eighty seven.
COMPLETE SPECIFICATION.
Improvements in Electrical Signalling Apparatus for Railways.
I, WILLIAM EDWARD LANGDON Electrical Engineer Midland Railway Derby in
the County of 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 following statement :-
In the combination of certain parts of Telephonic apparatus employed for the
purpose of conveying speech or other signals from one point to another with certain
parts of Electrical bells employed for Block signalling purposes on Railways in such
a manner that the combined instrument or instruments may be employed upon the
same wire which is used for the Block signalling Bell.
In order to effect this I where such can be advantageously arranged and where the
description of Telephone embraces the employment of an induction coil wind the coils
forming the Electro-magnet of the bell with a primary and secondary wire thereby
forming of the Electro-magnetic coils of the bell an induction coil for operating the
Telephonic apparatus. Where however it is found more desirable for convenience of
construction, or owing to the nature of the construction of the apparatus or for other
reasons I place the induction coil or other parts of the Telephonic apparatus on the
base board or other convenient position of the bell instrument independent of the
parts of the Block bell electrically connecting the several parts of the bell and
Telephonic apparatus so that the whole may be brought within and operated from one
and the same instrument:
Fig. 1 is a perspective sketch giving an outside view of a combined Block bell and
Telephone. Fig. 2 is a plan view of the same and Fig. 3 is a diagram shewing the
arrangement of the connections of the several parts such as would be necessary for
Telephonic apparatus embracing a transmitter and induction coil. The bell is of the
well knot form employed for train signalling on railways between signal boxes or

page_text: posts. A is a lever switch employed to place the Telephone apparatus in circuit and
to cut ile Block bell apparatus out of circuit as required B is a Telephone receiver
Ca Telephone transmitter D the bell key and E the bell dome N is the battery
employed for the induction coil of the Telephone transmitter M. the larger battery
employed in conjunction with N to signal on the Block bell. When the Telephone
receiver is in the position shewn viz. on the hook of the switch the weight of the
Telephone receiver hears down that end of the switch and thus places the Telephone
out of circuit and the Block bell in circuit. When it is required to speak on the
Telephone a preconcerted signal-a given number of beats-is rendered on the bell
and the Telephone is then removed from the hook of the lever switch which thus
relieved of its weight rises under the influence of the spring more clearly shewn
at F fig. 6 to the dotted position which arranges the circuit connections so that the
Block bell is cut out of and the Telephonic apparatus brought into circuit.
Let it now in explanation be assumed that combined apparatus such as is referred
to is provided for communication between the two signal boxes and that the instru-
ment is required for Block signalling work. The position of the Switch A will be
that shewn by the continuous lines in figs. 3 and 6. The metal bar forming the lever
of the switch and which is pivoted at y under the influence of the weight of the
Telephone B will be resting upon the contact stud and the insulated contact
spring will be free of the contact studs and was will the extreme end of the
lever A be also free of the contact v. The circuit arrangement will in this case be as
shewn in diagram fig. 3. An incoming current will pass from L to D along a to y
from y to thence by wire to the coils H and by wire c to carth. An outgoing
current would be obtained by pressing down the Block bell key D when on making
contact with the front stud of the key a current would pass from B C through the
key D to L and on to the distant station by the "Line" wire. The incoming current
on passing through the coils H would operate the armature and the bell would be
sounded once for every such current received.
Let it now he assumed that a signal has been rendered to make use of the Telephone
communication. The Telephone is removed from its position of rest on the hook of A
when the spring Fraises the lever A to the dotted position fig. 6. A is now free from
contact the insulated piece will now join and to together, and the extreme end
of A will rest upon and form contact with e. The switch A will now be in position
for Telephonic communication. Incoming currents will enter the instrument at L
pass through D along wire a enter lever A at y pass to through the coils H and the
Telephone B to earth. Outgoing currents would be brought into operation by the
action of the transmitter upon the induction coil H when the induced currents would
pass in one direction to line by wire lever switch A wire a signalling key D to L
and in the other direction to earth.
The coils H may be wound so that the primary wire shall form the circuit for
operating the Block bell or so that the secondary wire may be used for that
purpose.
Diagram fig. 7 indicates the arrangement of the connections for a simple Telephone
where no induction coil is employed for the transmitter A is the lever switch centered
at y' and normally resting upon contact with noninsulated contact springs free
from the contacts e te¹ when the Block bell circuit is complete And when under
the influence of spring F¹ with contact free and contacts w³ completed in which
position the connections are arranged for Telephonic communication. As represented
in fig. 3 N is the battery employed for the Telephone transmitter and M' in
conjunction with N¹ that used to operate the Block bell. H' are the Bell coils.
In operating this arrangement the action of the Block bell key D' and of the bell
will be the same as explained in relation to fig. 3. Let it be assumed that the signal
for making use of the Telephone has been rendered. The Telephone B₁ is now
removed from its hook and the lever A¹ under the influence of spring F¹ rises from
contact and completes the connection between ' and wel by means of the connecting
spring. The circuit is now complete for speaking by the Telephone. An incoming
current enters by the Line wire at L traverses key D' wire a' the spring spring w
to the Telephone B' and by terminal Z E to earth. An outgoing current would pass
1

page_text: terminal C wire all the transmitter or sending Telephone wire a to spring switch A'
wire a to Block bell key D' and to Line.
Figures 4 and 5 illustrate accessories for convenience in the use of the instruments
and relate to that portion of the Telephonic apparatus employed to speak into or
transmit the object being to extend raise or lower this portion of the apparatus so as
to make it convenient for the operator to speak to- is the speaking or transmitting
Telephone having its wires connected to two stiff rods of metal II terminated by
two plates K K insulated the one from the other so arranged that they may slide
into slotted pieces fixed to the base board or other convenient part of the main
instrument.
I would have it understood that I do not limit myself to the exact details herein
described as the same may be varied or modified without departing from the nature
of my Invention which consists essentially of the combination of apparatus employed
for Telephonic communication with the Block signalling bell employed between signal
boxes or parts thereof, so that a viva voce means of communication may be provided
between the signal boxes in conjunction with and upon the same wire as that used for
the Bell communication.
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. The combination of parts of Block bell and Telephonic instruments and
apparatus substantially as hercin set forth.
Secondly. The employment of one and the same line wire for the combined
purpose of Block bell signalling and speaking by means of Telephonic apparatus
substantially as set forth.
Thirdly. The employment of a Switch electrically connected with the Block bell
for the purpose of arranging the circuit connections as required-whether for Block
bell signalling or for speaking by the Telephone-substantially as exemplified in
figures 6 and 7.
Fourthly. The general construction and combination of parts as described and
shewn in the drawings.
Dated this Twenty ninth day of November 1887.
WILLIAM EDWARD LANGDON.