IMPROVE- MENTS IN ELECTRIC SIGNALLING APPARATUS APPLICABLE ALSO TO OTHER PURPOSES
Year: 1882

page_text: LETTERS PATENT to Louis John Crossley of Halifax, in the county of
York, John Frederic Harrison, of Bradford, in the county of York,
and Walter Emmott, of Halifax aforesaid for an invention of IMPROVE-
MENTS IN ELECTRIC SIGNALLING APPARATUS APPLICABLE ALSO TO OTHER
PURPOSES."
"6
PROVISIONAL SPECIFICATION left by the said Louis John Crossley,
John Frederic Harrison, & Walter Emmott at the Office of the Commissioners
of Patents on the 18th March 1882.
LOUIS JOHN CROSSLEY, of Halifax, in the county of York, JOHN FREDERIC
HARRISON of Bradford, in the county of York, and WALTER EMMOTT of Halifax
aforesaid, "IMPROVEMENTS IN ELECTRIC SIGNALLING APPARATUS APPLICABLE ALSO
TO OTHER PURPOSES."
This invention relates to improvements in magneto-electric or electro-magnetic
signalling apparatus for use in telephone exchanges, railway signal cabins, and for
telegraphic and telephonic purposes generally, the improved signalling apparatus
being also applicable to connecting and disconnecting wires used for telephonic,
telegraphic and other purposes.
For the purpose of illustration we will describe our invention as applied for use
in telephone exchanges.
We take an ordinary magneto-electric call bell and to the spindle of the revolving
coil or coils we adapt one or more cams, pins or the like, so that it or they will
make contact with a suitably placed spring or springs or its or their equivalent in
such a manner that when the said coil or coils is or are rotated the electric currents
are caused to flow out to the line in the direction or directions required by
operating a key or by other suitable means.
By this arrangement the subscribers to a telephone exchange in addition to the
ordinary call signal are enabled to transmit a distinct and separate signal to advise
the exchange operator that the wires are free.

page_text: By the employment of relays or other suitable electric apparatus in the central
office such currents may be transmitted as will enable a subscriber to disconnect
his wire from the last subscriber with whom he spoke and place both lines in
connection with the switch board without the intervention of the operator.
The application of our invention for other than telephonic purposes will be
understood without further description.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Louis John Crossley, John Frederic Harrison, & Walter Emmott
in the Great Seal Patent Office on the 16th September 1882.
LOUIS JOHN CROSSLEY of Halifax in the county of York, JOHN FREDERIC
HARRISON of Bradford, in the county of York, and WALTER EMMOTT of Halifax
aforesaid "IMPROVEMENTS IN ELECTRIC SIGNALLING APPARATUS, APPLICABLE ALSO
TO OTHER PURPOSES
31
This invention relates to improvements in magneto electric or electro-magnetic
signalling apparatus for use in telephone exchanges, railway signal cabins, and for
telegraphic and telephonic purposes generally, the improved signalling apparatus
being also applicable to connecting and disconnecting wires used for telephonic,
telegraphic and other purposes.
For the purpose of illustration we will describe our invention as applied for use
in telephone exchanges.
We take an ordinary magneto-electric call-bell apparatus and to or in connection
with the axis or spindle of the revolving coil or coils we adapt one or more cams,
pins or the like so that it or they will make contact with a suitably placed spring
or springs or its or their equivalent in such a manner that when the said coil or
coils is or are rotated the electric currents are caused to flow out to the line in
the direction or directions required by operating a key or by other suitable means.
By this arrangement the subscribers to a telephone exchange in addition to the
ordinary call signal are enabled to transmit a distinct and separate signal to advise
the exchange operator that the wires are free.
By the employment of relays or other suitable electric apparatus in the central
office such currents may be transmitted as will enable a subscriber, when it is
convenient so to do, to disconnect his wire from the last subscriber with whom he
spoke and place both lines in connection with the switch board without the
intervention of the operator.
In order to enable our invention to be better understood we will proceed to
'describe a suitable arrangement for carrying the same into effect when used for
telephone exchanges by reference to the accompanying drawing in which figure 1,
represents a view of a coil such as is generally used in the magneto-calls, or call
bell apparatus now in use but any other suitable form of coil may be employed in
carrying out our improvements. Figure 2, represents a sectional view of the
metal body of the bobbin of the coil fitted with a spindle cam and springs according

page_text: to our improvements. Figure 3, represents a view shewing a suitable arrangement
for connecting an indicator with our improvements and figure 4, represents an end
view of the bobbin and cam shewn in figure 2. Similar letters in all the figures
represent similar parts.
In carrying out our improvements the ends of the wire of the coil A are
connected respectively to the small pins P, and P¹, figure 2, the pin P¹, is insulated
from the metal body of the bobbin and connected with the spindle S, which is
also insulated from the bobbin. On the spindle S, is fitted the cam C, (or a pin
or its equivalent may be employed); the cam C, revolves with the coil and at each
revolution makes contact with the spring or springs J, and J¹.
From this arrangement it will be seen that the currents induced into the
armature may be taken off in any position of rotation by employing a suitably
shaped cam or its equivalent and thus all the positive currents or all the negative
currents or both the positive and negative currents may be readily taken off at
will by interposing in the circuit a key K, as shewn in figure 2.
As connected up
in this case it will be seen that the depression of the key K, will send only currents
of one direction to line, while the key K, not being pressed will allow both
positive and negative currents to flow to line. It will be convenient in using this
system in telephone exchange lines to engrave on the key the words "
by which a subscriber will know that by depressing the key K, he can intimate
to the central exchange that he has finished communicating and wishes his wire to
be put straight again.
ring off"
For this purpose an indicator may be used in the central exchange on the
principle shewn in figure 3, where M, is a curved magnet held in position by
gravity over a coil or coils of wire B. This magnet will not be deflected by the
rapidly following positive and negative currents transmitted without pressing the
key K; but the moment the key is pressed the magnet is deflected, the contacts H,
come into the mercury cups N, (or into other suitable contacts) and close a local
circuit L, in which may be placed a bell indicator or other means of attracting the
operator's attention.
By using a polarized relay or other suitable means the subscriber can disconnect
his line from the last subscriber with whom he spoke and place it back to the
operator's switch board by arranging the relay so that the current transmitted
from the magnet when the "ring off is used shall deflect the tongue of the relay
to a stud connected with the switch board, the tongue being connected to line;
other useful combinations may be arranged as will be evident from the general
description herein given.
If the curved magnet M, be weighted slightly on one side it may be used without
a local circuit and additional apparatus, as the indicator I, will fall over when
deflected and remain until put back.
There are numerous other useful applications of this system for instance an
intermediate station can be arranged with two terminal stations so that the
terminals can speak with each other or with the intermediate station the switching
being done by the station wishing to speak as will be well understood without
further description.
The system is also applicable to the working of electric signals on railways
instead of using batteries as at present for example the " ring off" key or other
suitable arrangement will enable the operator to transmit the currents so as to
indicate "line clear" and "line blocked" or otherwise as required.
Having thus described our invention and a suitable manner of carrying the
same into effect we wish it to be understood that What We claim is :—
Firstly. The application to or in connexion with the axis or spindle of the
revolving coil or coils of a magneto-electric call-bell apparatus of one or more cams,
pins or the like in combination with suitable contact springs and connections
whereby in addition to the ordinary call signal, a distinct and separate signal may
be transmitted to advise the exchange operator that the wires are free substantially
as herein before described.

page_text: Secondly. The employment in combination with a call bell apparatus substan-
tially as herein described of relays or other suitable electric apparatus in the
central exchange office whereby a subscriber to a telephone exchange will be
enabled to disconnect his wire from that of the last subscriber with whom he
spoke, and place both lines in connection with the switch board without the
intervention of the operator substantially as hereinbefore described.
Thirdly. The application of call bell apparatus constructed substantially as
herein before described to the working of electric signals on railways instead
of using batteries as at present, substantially in the manner described.
In witness whereof we the said Louis John Crossley and Walter Emmott
for and on behalf of ourselves and the said John Frederic Harrison, have
hereto set our hands and seals this fourteenth day of September in the
year of our Lord one thousand eight hundred and eighty two.