Improvements in or relating to Signalling and Communicating by Telephony, and in Apparatus used therewith.
Year: 1895

page_text: Date of Application, 22nd Mar., 1895
Complete Specification Left, 23rd Dec.. 1895-Accepted, 29th Feb., 1896
PROVISIONAL SPECIFICATION.
Improvements in or relating to Signalling and Communicating by
Telephony, and in Apparatus used therewith.
I, HAROLD JAMES BENTLEY of 17 Newton Street, Manchester, Electrician,
do hereby declare the nature of my said invention to be as follows:-
My invention has reference to a novel system of signalling or communicating
by telephony, chiefly between a number of telephonic stations, whereby all, or
each of such stations may communicate with each other, and whereby no two
stations can be interrupted or overheard at other stations except at the will of the
users.
My invention also comprises a novel arrangement of key board whereby the
speaking line is automatically completed by the ringing of the bell, and without the
use of loose plugs or switches as heretofore, an essential feature of such apparatus
being that the completing of the speaking circuit is only effected by the act of
ringing the bell at one or both stations.
In accordance with my invention and as applied to a set of instruments or key
boards for use say between twelve different stations, or say between twelve different
departments in a manufacturing establishment where it is desired to connect all
such departments with each other, I employ an instrument or key board at each
station containing eleven electro magnets each representing a particular department
and connected by its own particular wire to the contact piece of a switch or push
of a similar instrument at the distance station and such wire forming the bell
circuit between the two instruments.
To each of the electro magnets I apply a small armature held clear of the
magnet by a spring blade when no current is flowing through the electro magnet,
but drawn down on to the magnet when a current passes through the hell circuit.
Each armature forms a latch and when clear of the magnet engages with the top
end of a, by preference, thin blade of metal (hereinafter called the shutter) which
is mounted on a centre about one third from its lower extremity so that when the
armature is attracted by the magnet, such shutter falls forward and so affords
a visible indication that the department connected with the particular electro-
magnet desires to open up communications. The act of tilting forward causes the
lower end of the shutter to complete the speaking circuit at that particular
station, say by its shorter arm pressing two contact plates together in electrical
contact with the telephone receiver and transmitter, or by pressing against a single
contact plate with the centre of the blade in similar electrical contact.
The arrangement of the apparatus and electrical connections being precisely the
same at each station, it will be necessary before the speaking circuit is fully com-
pleted, or before a message can pass between two stations, to give a reply
ring and thus release the shutter and complete the speaking circuit at the other
station.
The connections of all the other maguets and circuits being precisely the same
for each of the twelve stations any one station may speak to the other eleven.
The speaking circuits not being completed until both shutters have dropped
down or the bells at both ends have rung, it will be obvious that when two
departments are using the telephone it will be quite impossible for another
department to interrupt or overhear until the reply ring has been given.
The electro magnets are, by preference arranged side by side and on a longi-
tudinal rail immediately behind the front of the instrument casing so that the

page_text: shutters may fall through slots formed in such casing and for facility of communi-
cation mark the name of the particular station with which each shutter
communicates upon the casing front or upon the shutters themselves.
For further convenience I arrange the keys, in a line and projecting through the
instrument casing and coming directly beneath or opposite to the particular shutter
to which it belongs.
After speaking the shutters are pushed up again and the armatures aforesaid
receive and latch such shutters in their vertical positions ready for the next
signal.
Although herein before described as applied to a system of intercommunication
between a number of stations I wish it to be understood that my invention is
equally applicable to cases where it is desired to connect only one department to
a series of departments, say a general office with three or four sub-offices or
departments. In such cases a single magnet instrument will be in each department,
and a three or four magnet instrument (according to the number of departments)
in the general office.
A modification of my invention consists of a single shutter system, the ringing
of the bell from one instrument being sufficient to complete the entire speaking
circuit.
This arrangement may be very conveniently applied in the case described
in the preceding paragraph, i.e., between a general office and different departments,
the shutters for completing the circuit being, by preference applied to the
instrument in the general office.
An important advantage which accrues from my invention is the silent, but
visible indication which is given by the falling shutters enabling the user in case
he has been out of hearing or reach of the instrument to know by observing the
fallen shutters who has been wanting him in his absence.
Although I have described my invention as applied to a two wire, or bell and
speaking circuit system of telephony, it is equally applicable to a single wire
systen, the contacts being varied accordingly. In this modification the falling of
the shutters will be arranged to complete the speaking circuit whilst simultaneously
"cutting out" the bell circuit, and the pushing of the shutters up will be arranged
to complete the bell circuit whilst simultaneously "cutting out" the speaking
circuit.
In lieu of a bell signal, any other form or kind of signal may be employed.
Dated this 21st day of March 1895.
Improvements in or relating to Signalling and Communicating by
Telephony, and in Apparatus used therewith.
"
I, HAROLD JAMES BENTLEY of 17 Newton Street, Manchester, Electrician,
do hereby declare the nature of my said invention and in what manner the same
is to be performed to be particularly described and ascertained in and by the
following statement :--
My invention has reference to a novel system of signalling, or communicating by
telephony, chiefly between a number of telephonic stations, whereby all (or each)
of such stations may communicate with each other, and whereby no two stations
can be interrupted or overheard at other stations except at the will of the users.
Such system embodies a novel construction of "key-board in which loose
"plugs,"
line selectors," or "switches" are dispensed with, the opening-up of
communications between two or more stations being effected automatically by the
operation of signalling, and a characteristic of such key-board being (by
"
"
"

page_text: preference) that the signalling from one telephonic station only partially completes
the speaking circuit, and that the reply signal requires to be given before the
speaking circuit is fully completed.
And in order that my said invention shall be the more readily understood and
carried into practical effect I have hereunto annexed a sheet of drawings and will
now proceed to describe the same with the assistance of the various figures and
letters of reference marked thereon.
On Sheet One, Fig. 1 illustrates a front exterior view (partly broken away to
shew interior) of a "key-board," embodying my invention, and adopted for com-
munication with five other key-boards, and shewing its connections to a receiver
and transmitter, or hand micro-phone and receiver (on reduced scale and in
dotted lines) which may be used therewith. Fig. 2 illustrates a transverse section
of such "key-board" with diagram of its connections to one of the five other key-
boards, and for the purpose of distinction, such key-boards are marked (A) and (B)
respectively. Similar letters denote similar parts in all the views.
In accordance with my invention, and as applied for communication or inter-
communication, between a series of six stations, I employ a "key-board" at each
of such stations containing five electro magnets (C), each representing the five
departments with which the sixth (or home) station is to be connected. These
magnets are arranged compactly together on a rail (D), and above each of such
magnets is an armature (F), held flexibly by the thin metal arm (G) from a
metal bracket (H). The front end of such armature forms a latch, and, when
said magnet is not energised, engages with thin sheet metal plate (I) (hereinafter
called the signal shutter) pivoted upon its own special and separate axis or
centre (J).
Projecting through holes in the front of the casing (E) is a series of "pushes" (K),
one push for each magnet (or station) as shewn more clearly in Fig. 1, and directly
behind such pushes and fitted to the casing front as illustrated are five spring
metal contact plates (L). These latter normally lie in contact with contact
pieces (M) (one piece for each plate), and directly behind such plates (L) is a
contact (or "omnibus") bar (N) running the full length of the key-board and
common to all the said plates (L).
Each of the five contact plates (L) and the. bar (N) of a key-board form part
of a signalling circuit extending through a contact piece (M), and plate (L) of one
of the other key-boards, and when such plates and bar are in contact complete
their respective circuits, but, under their elasticity, the plates lie normally out of
contact with the bar (N), and keep such circuit broken.
Each of the said circuits whilst including a plate (L) and the bar (N) in key-
board (A), a plate (L) and contact piece (M) in one of the other key-boards, as
represented in key-board (B), also includes one of the electro magnets (C) in suc!!
other, cr key-board (B), and such magnet corresponds to the name of the user of
the key-board (A).
With the circuit completed by pressing a plate (L) into contact with bar (N) in
key-board (A), and in circuit with one of the said magnets (C) in key-board (B),
the current of electricity, from the circuit battery (0), energises the magnet, ani
causes it to at once attract its armature (F), and lowering it out of latchment with
the signal shutter (1) causes such shutter to fall forwards through a slot or
opening (P) in the key-board front as shewn in key-board (B), and thus indicate
to the user of such key-board, that the user of key-board (A) (as indicated by the
name plate above or below the shutter opening) desires to speak.
Simultaneously with the falling of the shutter and attraction of the armature (F)
a spring contact plate (Q), secured to the armature, is caused to come in contict
with a contact (or "omnibus") bar (R), and these being connected respectively
with the terminals of a bell circuit, complete such circuit and cause the ringing of
the bell, and the giving of an audible signal in addition to the visible signal given
by the shutter.
In this way a signal is given from one key-board (or station) to another, or say

page_text: from key-board (A) to key-board (B), and the fittings and connections of key-
board (B) being identical with those of key-board (A) (and all other key-boards),
the pressing of a push (K) in key-board (B) completes the circuit extending
through plate (L) and contact pieces (M) in key-board (A), energises the magnet
with which it is in circuit in key-board (A); drops the corresponding shutter
signal; completes the bell circuit; and so gives the reply signals, audible and
visible.
Simultaneously with the falling of a shutter in either key-board, the point (S)
of such shutter bears against a spring contact plate (T) in circuit with a speaking
line or wire, and the axis of such shutter likewise being in circuit with such line,
the speaking line is completed in the particular key-board.
From this it will be seen that the speaking circuit (being broken in each instru-
ment) requires the falling of a shutter in both instruments, or the giving of the
reply signal before a message can pass, and in this a safeguard is afforded for
preventing a message passing from one station to another being overheard by
a third station, since, with the transmitter and receiver of the key-board and earth
return connections common to all the speaking circuits, such would be possible if
the reply ring were given, but no reply ring being given the third party cannot
over-hear, or interrupt the message.
Contrawise, if it is desired that such third party should open up communications
the reply ring is given and all three operators can hear and speak to each other.
In this way and owing to the earth connection being common to all the speaking
circuit as aforesaid, the operators can speak to each other directly, or through any
one or more of the other operators, but the drawback to this latter is that it
requires the 'intervention of the intermediate operator, who may or may not be
in attendance, and who may overhear the message. Direct communication is
therefore better for communication between station and station, and indirect when
others are desirous of joining in.
The square (U), with letters
(E) (earth, or carbon of batter (L) (speaking line), (Z) (lead of battery); and
represent the terminal connections of any
telephone, microphone and receiver (with or without an induction coil), or the
terminal connections of a microphone and receiver in connection with a battery,
and with a circuit breaking device when not in use. A convenient form of such
latter instrument and connections are shewn by dotted lines in Fig. 1.
After speaking the fallen shutters are pushed up again and retained by their
latch ready for the next signal.
33
Notwithstanding that a shutter has fallen and has " ** switched on the speaking
line, or that the finger has once been removed from the push (K) it will be
obvious that the ringing of the bell can always be effected or continued.
In lieu of the axis of the signal shutters (I) being in circuit with the speaking
lines, a spring contact plate (see dotted lines in Fig. 2) may be arranged behind
each of the plates (T) in circuit with the speaking line, and when pressed
together by the shutter point, completing such circuit as aforesaid.
In the case of inter-communication between a large number of key-boards,
where separate contact plates (Q), and connections for each key-board would
envolve considerable expense and trouble in fitting, I may use a "relay" in
each key-board common to all the magnets therein, and introduced electrically
into the respective signalling circuits, say as indicated at (V) in Fig. 2, or in
other words all such signalling circuits passing through it, and distributed to
their respective magnets from the point (W), or directly from such "relay."
This "relay" also forms part of or controls the bell circuit, and on the com-
pletion of any one of the signalling circuits, such bell circuit is also completed,
and gives an audible signal. In this way I may effect an economy of fittings, the
"relay" being common to all the magnets, and signalling circuits.
The improved key-boards, and system of connections may be applied to any
number of stations, or may be used between two stations only, the respective
connections and actions being precisely the same in all cases.

page_text: My invention is equally applicable to cases where it is desired to connect only
one station to a series of stations, and not to each other, say a general office with
three or four sub-offices. In such cases a single magnet instrument will be in each
sub-office, and a three or four magnet instrument (according to the number of sub-
offices) in the general office. By the reciprocative signals of this arrangement the
users could all speak to each other, but only through the four magnet key-board.
A modification of my invention consists of a single shutter system, the ringing
of the bell from one instrument being sufficient to complete the entire speaking
circuit. This arrangement may be very conveniently applied in the case described
in the preceding paragraph, i.e., between a general office and different departments,
the shutters for completing the circuit being (by preference) applied to the
instrument in the general office.
Although I have described my invention as applied to a two wire, or bell and
speaking circuit system of telephone, it is equally applicable to a single wire
system, the contacts being varied accordingly. In this modification the falling of
the shutters will be arranged to complete the speaking circuit, whilst simultaneously
"cutting out," or changing the contacts of the bell circuit, and the pushing of the
shutters up will be arranged to complete the bell circuit, whilst simultaneously
"cutting out "the speaking circuit.
In lieu of a bell signal any other form or kind of audible signal that can be
electrically actuated may be employed.
Having thus 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 and desire to secure by Letters Patent is :-
1st. A system of telephonic communication, or inter-communication between
telephonic stations whereby each can speak to all, and all to each, directly or
indirectly, and wherein the speaking circuit is automatically completed by
signalling circuits and (by preference) in two stages, partly by the initial signal
and completely by the reply signal, as set forth.
$6
2nd. In a system of telephonic communications, or inter-communication between
telephone stations, the use of a key-board" at each station containing electro-
magnets (C), contact plates (L) and (M), spring contact plates (T) and signal
shutters (1) corresponding to the number of stations to be communicated with,
" omnibus contact bars (N) and (R) and spring contact plates (Q) (or their
aforesaid "relay" equivalent), mounted and operating as set forth and illustrated.
3rd. In a telephonic "key-board" the use and combination of an electro-
magnet (C) with signal shutter (I), this latter normally retained within the key-
board by latchment with the armature of said magnet, and released by the influence
of a signalling circuit passing through said magnet for partially or wholly
completing the speaking circuit as set forth.
4th. In telephonic communication between a series of telephonic stations, where
one is in direct communications with all and all with one, but not with each other,
the use of a key-board with fittings and electrical contacts for communicating with
a series of key-boards, and in each of such series of key-boards electrical contacts
and fittings for communication with one key-board, as set forth.
th. In telephonic communication or inter-communication between a series of
telephonic stations, the use of a single wire connection for speaking and signalling
purposes, in combination with my improved key-board, and serving to release the
shutters (I) whilst signalling, and thereby complete the speaking connections, as
set forth.
Dated this 20th day of December 1905
HAROLD JAMES BENTLEY,
By John G. Wilson & Co.,
Agents.