Improvements in and relating to Electric Signalling Apparatus, Chiefly Designed for Use in Connection with Telephones.
Year: 1886

page_text: Improvements in and relating to Electric Signalling Apparatus,
Chiefly Designed for Use in Connection with Telephones.
I, HENRY HARRIS LAKE, of the firm of Haseltine, Lake & Co, Patent Agents,
Southampton Buildings, in the County of Middlesex, 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 :-
This invention relates to an electric signalling apparatus such as used on
telephone circuits and commonly known as an individual signalling apparatus,
there being a number of signalling instruments at different points or stations in
one circuit properly constructed to enable any desired one of said signals to be
operated without the others.
0
t
The invention is embodied in a signal controlling instrument comprising an
electro magnet in the main circuit having neutral or soft iron cores acting on
different armatures, one of which may be called the actuating armature and has a
vibratory movement towards and from the poles of the magnet, in which move-
ment it actuates a step by step device and after one particular step, or at one
definite position arrived at after a movement produced by a definite number of to
and fro movements of the armature, after the step by step device starts from a
given point called the unison point, the said step by step device places the signal
controlled by the said instrument in condition to be operated by a current of
proper character. Each of the signal controlling devices at the different stations,
places the signal controlled. by it in condition to be operated, after a different
number of movements froin the common starting point, so that only one signal is
in condition to be operated at the end of any given number of movements, and
each signal may be operated as desired by producing the proper number of
movements for that particular signal as is usual in individual signal apparatus,
containing step by step devices.

page_text: The step by step devices, actuated by the vibrations of the neutral armatures in
the different instruments as just described are each provided with one member of a
stopping device which at a given point in the step by step movement is engaged
by the co-operating member of the said stopping device, that is connected with
another neutral armature herein called the unisoning armature, operated by the
same electro magnet as the vibrating or step by step armature and being so
proportioned in size and provided with a retractor of such strength that at the
first attractive impulse by which the step by step armature is actuated, the said
unisoning armature will be attracted to the poles of the magnet and will remain
held there by the residual magnetism during the subsequent variations in magnetic
condition by which the step by step armature is actuated. When however short
impulses of alternating polarity, such as produced by magneto electric machines,
are caused to act on said magnet, their effect is to neutralize or destroy the residual
magnetism, thus releasing the unisoning armature and permitting it to disengage
the stopping device, which has held the step by step device, releasing the latter at
the proper starting point corresponding with the other instruments, all of which
have been engaged by their corresponding stopping devices and released simul-
taneously in proper relation, or in unison with one another. The step by step
device as shown in this instance, places the corresponding signal in operative
condition at one particular step in its movement, by opening a normally closed
shunt around the said signalling instrument, which is of the proper character to be
operated by short impulses of reversed polarity such as commonly produced by
magneto electric generators, and which do not affect the step by step actuating
armature in passing through the coils of the magnet.
The step by step device is also made to control the telephone or other instrument
at the said station, enabling the telephone to be placed in circuit only when the
signal at the same station is in circuit or when the signalling devices are at the
unison point. Thus when the signal at any station is operated the telephone at
that station only, on the line can be placed in circuit, thus maintaining secrecy so
far as the other stations of the said circuit are concerned.
The step by step device is also controlled by the telephone supporting switch,
which when the weight of the telephone is removed therefrom, mechanically
operates a stopping device for the step by step device arresting it at the unison
point and thus placing the telephone which has been removed from its hook,
previous to the operation, of the signalling device, in circuit so that a subscriber
who wishes to be placed in communication with another on the same line will by
removing his telephone from the hook to communicate with the operator at the
'central office, cause the said telephone to be placed in circuit when the operator at
the central office causes the signal controlling device to be brought to the unison
point, and the said telephone will be retained 'in circuit by the mechanical device.
or stop while the central office operator calls the other station, in which latter
operation the telephones at all other stations will be cut out of circuit.
&
The magnet of the signal-controlling instrument is also provided with an
armature, which short circuits the telephone and other apparatus at the station,
in case it should accidentally be left in circuit, so that the said telephone or
apparatus will not by its resistance so weaken the current as to cause the step by
step actuating armature to fail to operate. The said short-circuiting armature
itself has a comparatively weak retractor, so that it will be operated even if the
telephone should be in circuit, and it accompanies the step by step actuating
armature in its to and fro movements or moves up slightly in advance thereof in
'case the resistance is in circuit, in which case the actuating armature will follow
each movement of the short-circuiting armature after the resistance has been
removed by the latter.
Besides the general combination and arrangement of the signal and telephone
controlling devices, the invention further consists in details of construction, the
objects of which are to render the step-by-step device extremely certain in
operation, and to simplify and reduce the expense of the instruments.

page_text: In the accompanying drawing
Figure 1 is a plan view of a signal controlling instrument embodying this
invention.
Figure 2 is a front elevation thereof.
Figure 3 is an enlarged detail of the step by step actuating device, and
Figure 4 is a diagram showing the circuit connections of the signal controlling
instrument with the other apparatus at a station.
The signal-controlling instrument is shown as supported on a block a which may
be of wood bored to receive the actuating magnet b, shown in dotted lines Figure 2,
the poles b¹ of which project up through a plate e provided with bearings d for
shafts or pivots e, e¹, for one end of the armatures f, f¹ of the said electro magnet b;
and for the shaft g of the step by step device which comprises a ratchet g¹ on the
said shaft and actuating pawls h, h¹, therefor, connected with a frame i¹ fixed upon
the armature of the magnet b as best shown in Figure 3. The retractor for the
armatures ff are shown in Figure 1, as springs f³, f³, bearing against the under
sides thereof. The block or frame piece a may be supported on the box, containing
a magneto generator G, see Figure 3, signal S, and switch t for supporting the
telephone T, all of which may be of usual construction and are only indicated. in
the diagram, Figure 4. When a series of electrical impulses of proper strength
and duration, which will be called actuating impulses or currents, are imparted to
the circuit of the magnet b, such for instance as produced by alternately breaking
and closing the circuit while a battery is included therein, the armature f will be
vibrated to and fro, and at each to and fro movement will advance the ratchet g¹
for the space of one tooth, and the movement of the said ratchet will thus
correspond to the number of such impulses applied to the magnet b.
The shaft g, of the said ratchet, which thus receives the step by step rotatary
movement, is provided with an arm or projection kc, best shown in Figure 4, where
the said shaft is shown in perspective, and the said arm k, at one step in the
movement of the shaft, acts upon one member ¹ of a circuit-controlling device,
separating it from the other member 2 thereof, and thus opening the circuit
between the said members at this particular step in the movement of the shaft,
although the said members are connected, and the circuit closed between them
when the shaft g is in any other position. The members k¹, k³, are in a shunt or
branch of low resistance around the signal instrument S, and normally when in
contact, divert the current from said instrument, which can thus be effected only
when the shaft g is in the particular position shown in Figure 4, at which the said
members k¹, are separated and the signal S in circuit. It will be understood
that the shaft g of the instruments at different stations on the same line are all
moved simultaneously by the vibrations of the armatures f of the said instruments
and that the arms k, of the different instruments are at different positions with
relation to the member k¹ of the circuit controlling device, so that only one of the
said members will be engaged by the arm k in any one step in the simultaneous
movement of the shafts g, and that the said members k¹ at the different stations
will be engaged one after the other in the said movement, so that it is necessary, in
order to call any given station, that the shafts g should all be rotated far enough
for the one to engage the member k¹ at that particular station, when the signal s at
that station and at no other will be in circuit, after which the said signal may be
operated by currents of such character as will not appreciably affect the armatures f
of the different instruments, the signal S being for instance, operated by the short
impulses of alternating polarity that are generated by the magneto electric generators
commonly employed in telephone signals.
In order that the shafts g of the instruments at the different stations may
always be in proper position with relation to one another, or may. be brought into
such position in case any one has gained or lost a step with relation to the others,
means are provided for bringing the said shafts or step by step devices into unison
with one another before being operated to produce a signal. In order to effect
the unisoning of the said shafts they are each provided with one member m of a

page_text: stopping device, shown as consisting of an arm, provided with a short laterally pro-
jecting finger, which in the rotary movement of the said shaft is engaged by the
cooperating member m' of the stopping or unisoning device the said member m¹
being carried by an armature m³, shown as placed at the sides of the pole b¹ of the
magnet b, and connected with or supported on a spring m³ which tends to retract
the said armature or move it away from the poles of the magnet, in which retracted
position the stop member m¹ is also removed from the member m so as to release
the shaft g. The armature m³ is of soft iron and comparatively small and when
the magnet bis affected by the impulses which actuate the armature f. the
armature m will also be attracted and its retractive force is insufficient to over-
come the residual magnetism and withdraw it from the poles of the magnet b
during the short intervals which occur between the successive attractive impulses
that affect the armature f. When however currents of rapidly alternating polarity
such as operate the signal S act on the magnet b they immediately neutralize or
destroy the residual magnetism permitting the armature m³ to be retracted and
thus release the shaft g. The currents for actuating the armatures f and m³ and
the signal S are preferably applied by the operator who by manipulating a suitable
key, will first cause a number of impulses of proper character to affect the
armature f, to pass through the magnet b, sufficient to turn the shaft g at least a
full revolution and one or two steps beyond so that any shafts which may have
lost a step will have an opportunity to gain it, the armature' m³ being held up to
the poles of the magnet during and between these impulses, and the stop
members m thus being caused to engage the stop members m of the different
shafts as they arrive at the said members m', thus arresting the shafts in the same
position with relation to the stop members m¹ and with their signal controlling
arms & distributed in different positions with relation to said stop members and to
the members k¹ of the circuit controlling devices, so as to act successively on the
latter in the further movement beyond the stopping or unisoning point. A few
alternating impulses are then applied to the maguet b which cause the release of
the armature m² and the shaft g without affecting the armature for moving said
shafts, except for a very small fraction of a turn produced by the further retractive
movement of the armature f which was not quite complete when the stop member m
was engaged, and is sufficient to carry the latter beyond the member m¹, so that it
will not again be engaged when the actuating impulses begin. The shafts are
thus all released in unison with one another, and the operator or transmitter by
applying the proper number of additional impulses will cause the shaft g to turn
far enough to engage the member k¹ at the station that is to be singnalled, the
arms at the other stations either having passed beyond or not yet reached the
corresponding members k, which consequently will remain in their normal position
in contact with the members. The operator or transmitter then causes a series
of alternating currents to pass over the line, which operate the signal S at the
station where the circuit controlling device k¹ k is opened, but produce no other
effect, thus calling the desired station and that one only.
The shafts g are shown as also provided with telephone controlling devices or
arms n n, co-operating with a circuit controlling device o, o¹, similar in con-
struction to the one k¹, k² and forming a part of a shunt or circuit of low resistance.
around the telephone T, which shunt is closed preventing the telephone from being
placed in circuit at any given station, except when the signalling devices are at the
unison point, when the arms n which correspond in position to the stop members m
will engage the members o at all the stations; and when the arm k is in position
to place the signal S at a given station in circuit, the arm n¹ which corresponds in
position to the one will place the telephone T in circuit or in condition to be
circuited by its own switch at that particular station but at no other. Thus
persons at stations which have not been called or signalled cannot place them-
selves in circuit and overhear the conversation carried on by the person at the
station where the signal was operated. When a subscriber desires to call the
central office or produce a signal at another station than his own, a generator G see

page_text: Figure 4 is employed, being of usual construction, except that its commutator 8, 8¹.
is constructed to transmit only the intermediate impulses of like polarity, so that.
they will not affect the signal S of the station on the circuit that has last been
called, and at which the circuit controlling device k¹, k³ is left open by the step by
step signal controlling mechanism.
When a subscriber wishes to be placed in communication with another on the
same circuit, it is necessary to provide means for placing the telephones at both
stations in circuit without permitting the telephone to be placed in circuit at any
other station. To accomplish this, the instrument is provided with a stop member p
consisting in this instance, of a pin resting on a spring p¹, adapted to be engaged
and lifted by a rod p³, operated by the telephone supporting switch t, being raised
when the telephone is removed from the hook, as is done when the subscriber
signals the central office, the telephone being then placed in circuit by the operator
at the central office, actuating the step by step devices so as to bring them to the
unison point, at which point the stopping device p at the station where the
telephone has been removed from the hook, engages the stop member p of the step.
by step device preventing 'further rotation thereof, and thus retaining the step by:
step device of that particular instrument at the unison point and the telephone T
in circuit at that station, while the step by step devices at the other stations are
moved by the operator, at the central office, in order to call the other station, thus
placing the telephone at the station called in circuit by the arm n¹ of the step by.
step device, while the telephones at all the other stations are shunted by the circuit
closers o, o¹.
As the resistance of the telephonic instruments is quite large, it might interfere.
with the working of the armatures f if it were in circuit while the signalling.
instruments were being operated. In order to prevent such interference with the:
operation of the signalling instruments, the latter are provided with cut out
armatures f¹ operated by the magnet b but independent of the armatures f and m³
of the step by step and unisoning devices. The said armatures f¹ when attracted
close a shunt around the entire apparatus at the station, except the magnet b, and.
as the said armatures f' have no mechanical work to do their retracting springs'
are comparatively weak so that they will be attracted even if the resistance of the
telephonic instruments should be in circuit and as soon as they are attracted they
will remove the resistance so that the armature f is immediately attracted and thus.
properly operates the signals.
:
The mechanism for producing the step by step movement best shown in Figure 3,
consists of a frame i extending at opposite sides of, or rather more than half way
around the ratchet wheel g¹, or it might wholly encircle the said wheel g¹, this
frame having pivotted on it spring pressed pawls h, h¹ which engage the ratchet.
wheel at opposite sides thus turning the latter preferably for the space of one half
a tooth at each movement of the armature f in each direction. The said frame is
also provided with stop projections h, h³ which strike upon the wheel at the end
of the movement of the frame in either direction, thus limiting the said movement
and at the same time positively locking the wheel, so that it cannot turn beyond..
the point to which it is positively moved by the pawl last acting on it. This
mechanism very simple and at the same time very positive and certain in
operation, moving the wheel for the space of one tooth at each complete forward.
and backward movement of the. armature and being capable of operating at very
high speed without skipping a movement, and also without overthrowing or.
moving the wheels further than they should be moved by a given number of
vibrations of the lever.
The circuit may be readily traced in Figure 4. The main line entering. the
station at one side, is connected, as shown at 2, with one terminal of the magnet b
the other terminal of which is connected by wire 3. with the plate c of the
signalling instrument, which is also electrically connected with the springs.kland o
as indicated by the wire 4 in Figure 4, and with the armature f¹. The contact
point engaged by the said armature when attracted is connected by..wire.5 with

page_text: The
the main line 6 leading from the station, so that when the said armature is
attracted, the magnet b only will be in circuit, the branch wires 3, 5, constituting a
shunt for the remaining apparatus. From the wire 3 the main line is continued by
wire 7 and wire 8 branching therefrom, to one terminal, of the telephone T, the
other terminal of which is connected by wire 9 with the spring t¹ that is connected
with the telephone supporting hook or switch when the telephone is removed; but
when the telephone is on its hook the branch 8, 9, is open at t, t¹, as usual.
branch 10 from wire 7 passes to one terminal of the signal S, the other terminal of
which is connected by wire 11, including the generator G having the usual shunt
circuit 12 containing a normally closed switch G' and is connected with the contact
spring of the telephone switch t, which latter is connected with the main line 6
leading from the station. The member of the circuit closer, which controls the
signal, is connected by wire 13 with the branch wire 11, so that when the said
circuit closer is closed, and the telephone on its hook, the currents will pass over
the circuit 2, 3, 4, k¹, k³, 13, 11 (including the generator G or its shunt 12) t³, t,
and 6, without effecting the signal S; but when the members k¹, k³ are separated
and the telephone T on its hook, the currents will pass over the circuit 2, 3, 7, 10,
11, t, t, 6, including the signal S; the branch 8 then being open at t¹, the branch 4
at k¹, and also at o, o¹ or at t, t¹.
The member o¹ of the circuit closer o, o¹, is connected by wire 14 with wire 9, so
that if the said circuit closer is closed and the telephone off its hook the current
will follow the circuit 2, 3, 4, o, o¹, 14, 9, t¹, t, 6 without affecting the telephone T;
but if the said circuit closer o, o¹, is open the current will follow the circuit 2, 3,
7, 8, T, 9, t¹, t, 6 including the telephone, the branch 4 then being open at k¹, k³,
and o, o¹ and the branch 10, 11 being open at t as would also be the branch 4, 13,
if the circuit closer k¹, k² were closed. The armature fl is retracted and the
shunt 3, 5, open whenever the signal S or the telephone T are operated, it being
closed only during the impulses that actuate the armature f.
Having now particularly described and ascertained the nature of the said
invention and in what manner the same is to be performed, as communicated to
me by my foreign correspondent, I declare that what I claim is :-
First. A signal-controlling instruinent comprising a neutral electro-magnet and
actuating armature and retractor therefor; a step by step device actuated by the
said armature governing the operation of the signalling instrument; a stop member
connected with the said step-by-step device, and a co-operating stop member and
neutral armature connected therewith and retractor for the latter armature,
adjusted to cause the said armature to be attracted by the impulses that move the
actuating armature and to be held by residual magnetism between said impulses in
position to engage the stop members, and to be retracted when the magnet is
effected by currents of alternating polarity into position to disengage the stop
members, substantially as described.
Second. The combination of a step-by-step device, and neutral electro-magnet
and actuating armature and retractor therefor, with a stop member carried by the
said step-by-step device, a co-operating stop member and controlling armature
therefor held by residual magnetism in position to engage the other member and
arrest the step-by-step device at the unison point while the actuating armature is
being operated; a signalling instrument operated by currents of alternating polarity,
and shunt therefor; a circuit controlling device in said shunt operated by the step-
by-step device to open the said shunt at one step in its movement; a telephone
and shunt circuit therefor, and a circuit controlling device in said shunt circuit
operated by the step-by-step device, being opened when the said device is arrested
at the unison point and also when the shunt of the signalling instrument is opened,
substantially as described.
Third. The combination of the step-by-step device and electro-magnet and
actuating armature and retractor therefor with telephonic instruments connected
with the circuit of the said magnet, and a shunt for said instruments and arinature

page_text: operated by said magnet controlling the said shunt which is closed by the said
armature at each impulse that operates the step-by-step actuating armature,
substantially as described."
Fourth. A step-by-step device provided with a stop member, and with devices
controlling the circuit of a telephone and signalling instrument, combined with the
telephone supporting switch, and a stop member controlled thereby, being placed
by the said supporting switch, when the telephone is removed therefrom, in
position to engage the stop member of the step-by-step device and arrest the said
device in position to place the telephone in circuit, substantially as described.
Dated this LL
1800