Improvements in Electrically Controlled Switching Apparatus for Telephone or Telegraph Exchanges.
Year: 1892

page_text: Date of Application, 20th Sept., 1892
Complete Specification Left, 19th July, 1893-Accepted, 26th Aug., 1893
PROVISIONAL SPECIFICATION.
Improvements in Electrically Controlled Switching Apparatus for
Telephone or Telegraph Exchanges.
I, ROBERT PIPPETTE 31 Endymion Road Brixton Hill S.W. Architect and
Surveyor, do hereby declare the nature of this invention to be as follows:-
:-
Where it is required to connect several points electrically together, that is, by
conductors for the transmission of electric currents including telephonic and
telegraphic currents it is usual to connect each point by one or more wires to a
central point called an exchange where an attendant is stationed to connect the
various wires together as the persons using the wires desire.
It is evident that the number of wires under the control of one attendant inust
be limited and beyond this that the attendant can only attend to one person at a
time hence time is lost through persons who wish to communicate with other points
having to wait till the attendant can listen to them.
My invention briefly consists of apparatus by which a person at a point can
cause his own wires to be put into connection with the wire or wires of any other
person so that electrical communication can be carried on between them.
For this purpose each point is supplied with the ordinary telephonic or tele-
graphic apparatus and an apparatus for actuating and controlling the switching
apparatus at the central exchange. This apparatus is connected by one or more
wires to the central exchange. In the central exchange the wire or wires from the
point pass through the switching apparatus special to that point which can be
controlled from that point and by which a person can at will put his own wire or
wires into connection with those of any other point and having finished his
communication cause his own to be disconnected from them and also at will to
cause another points wires which may be in connection with his own to be
disconnected.
As a first principle it may be laid down that the wires from each point must be
brought within reach of the switching apparatus of each point so that the wire of
the individual point can be brought into connection with any given wire. These
wires may be either the speaking or controlling wire or both.
For this end the wire or wires of each point terminate in fixed metal contacts.
Each contact may be special for the switching apparatus of one point or common to
the apparatuses of 2 or more points.
The forms or shapes of the fixed contacts may vary.
The dimensions of these contacts may vary not only in magnitude but also in
relation to one another. Thus the length of a contact may be great compared with
its breadth and thickness, its breadth may be great compared with its length and
thickness, and its thickness may be great compared with its length and breadth, so
that at times they become plates bars rods studs pins tubes cylinders polygons or
any combination of such forms.
Then also it is customary to use one surface of contact as a contact surface,
but I use any side face plane or surface either separately or in combination.
The surface may be smooth polished rough corrugated or pointed.
To save room I use all faces and sides of the insulating supports to which the
contacts are fixed, and which may be of any shape required to carry the contacts in
the forms hereinafter mentioned.
These supports may be special to one or common to two or more contacts.
The contacts may pass right through to both faces of a support so that they

page_text: may be used on both sides, they may be flush projecting or sunk beneath the
surface of the supports.
The disposition or locus of the contacts will be governed by the locus of the
moving contacts which will in general be straight lines or circular.
The fixed contacts considered for this purpose as geometrical points may be
fixed in a plane in a straight line, in parallel straight lines, in a circle or concentric
circles. When fixed in paralled straight lines they may be in parallel straight
lines transversely or zig zag, and when in concentric circles they may or not
be in radial lines.
They may also be fixed on the surfaces of cylinders prisms or polygonal solids.
They may also be fixed on the surfaces of solids generated by a polygon or
circle revolving round at the same distance from a centre.
They may be fixed on spheres spherical surfaces cones pyramids, conical and
pyramidical surfaces or any line plane surface or solid generated or formed by any
section of any cone.
Two or more of like or different arrangements as above described may be used
together in parallel planes with like parts in the same straight lines or with
the same lines as axes and the same points as centres or in any other positions, in
contact or not.
Portions of these geometrical forms in which the contacts may lie may be used,
or used as a whole or in combination one with the other.
The insulating supports may possess the same geometrical forms as above
described, but it must be noticed that both sides or surfaces which compose these
geometrical forms may be used to fix the contacts to.
The moving contacts may move in straight lines, in circles, in circles about a
point which moves in a straight line, in circles about a point which itself moves in
à circle about another point.
The moving contacts are supported by holders which partake of the same motion
as the contacts. These holders may contain one or more separate contacts, and
may pass through the plane of the contacts to those on the other side of the plane
or surface. The holders may be branched bent and lengthened as required.
The contacts will consist of metal planes wheels brushes or springs kept in
contact with the fixed contacts by guides which receive projections from the
holders or contacts.
The holders may be of metal or insulating substance.
The holders and contacts may be supported and moved by arms or cords. These
arms rods or cords may carry the wires communicating with the contacts or the
wires may be flexible and quite separate from the holders.
The arms and rods may be fixed may be fixed to and moved by axles hollow or
solid. The contact holders may be also supported and moved by cords wound on
drums or reels also connected with axles.
The force used to move the contacts may be that derived from electricity gravity
or springs.
The way in which I cause the moving and fixed contacts to make contact may be
one or a combination of the following methods.
Having arranged the fixed contacts in certain lines I cause a moving contact
to move to the beginning of the line in which the contact. I require is fixed, and
then cause it to move along the line of fixed contacts until it reaches the required
contact or vice versa.
Having arranged the fixed contacts in lines I arrange a moving contact at the
beginning of each line then my mechanism moves the moving contact belonging to
the line in which the required contact is down to it.
Having arranged the fixed contacts in lines I arrange a moving contact at the
beginning of each line and then move the whole number of moving contacts
along the lines until one of them touches the required fixed contact then I make
connection through that one.
All these movements are made by the switching apparatus under the control of

page_text: the apparatus at the points and are made by magnets which are brought into action
at will by a circuit changer under the control of the person at the point or automa-
tically by the switching apparatus itself.
In the first case with the circuit changer, a circuit is made between the point and
the exchange including a contact maker at the point, a wire, a battery the circuit
changer and the earth as the return. The circuit changer contains a magnet which
by a step by step movement causes a radial arm to move round a centre. its outer
end passing over a series of contacts each of which communicates with some electric
magnet to work part of the switching apparatus.
A circuit may now be made up as follows, a contact maker is fixed at the point
one terminal connected to the wire before mentioned, the other passing to another
wire between the point and the exchange, through the arm of the circuit maker to
the contact upon which it rests through the magnets in communication with it,
through the battery that works the circuit changer and thence by the first wire
back to the contact maker at the point.
One wire of the circuit changer is reserved for telephonic apparatus and commu-
nicates with the moving contacts of the switching apparatus, so that the second
wire can be used for speaking as usual.
Another way in which I make the changes in the switching apparatus is by
using a timeing apparatus which will make the changes when a certain interval of
time has elapsed since the last current.
Such timeing apparatus may consist of a bellows which will be inflated by the
first current received and be kept from closing if the currents are sufficiently
frequent should a certain interval of time elapse since the last current the bellows
will have closed and altered the mechanism so that the next current will work a
different set of mechanism and expand its bellows and so on. I can use a pendulum
movement or springs or gravity by which I can cause the necessary changes to
be deferred for the required interval of time.
To make this clear I will explain one form of the automatic switching apparatus.
See Figure 1. 1 is the earth wire and will represent the earth acting as a return
common to all stations.
Circuit 1. From terminal of the contact maker 2 at the point, through the
controlling wire 3, the battery 4 at the exchange, through terminal 5, the wire 6,
the relay magnet 7, the wire 8, the terminal 9, to earth and back to the other
terminal of the contact maker 2.
Circuit 2. The circuit passes from one terminal of the battery 10 in the exchange
through wire 11, the terminal 12, wire 13 to the insulated screw 14, then through
contact 15 when it touches the screw 14, through keeper 16, insulated screw 17,
wire 18, magnet 19, wire 20 insulated screw 21 spring contact 22, wire 23, terminal 24,
wire 25 to other terminal of battery 10.
Circuit 3. This is the same as the last up to screw 17 when it passes by wire 26
to insulated screw 27, contact 28 keeper 29 wire 30 magnet 31 wire 32, terminal 33
relay 35 wire 36 terminal 37 wire 38 contact 39, spring contact 22 when it touches
contact 39 wire 23 terminal 24 wire 25 to battery 10.
Circuit 4. This is the same as the last up to insulating screw 14 whence it passes
through wire 40 to the insulating screw 41 thence through contact 28 when it
touches screw 41 to the battery 10 as the last circuit.
To save a multiplicity of connections I have arranged to have the speaking
wire from each point brought to a bar fixed on the face of the board 42. There
will be as many bars as there are points, some of the bars are shown in section
at 43, 43. They pass under the switching apparatus of each point and are therefore
common.
The speaking instrument 45 of the subscriber to whom this switching apparatus is
allotted, say No. 1, is connected to the earth by wire 46 and to the terminal 48 by
the wire 47. Thence through the wire 49 to other places. First to the reel 50 (not
shown) the cord 51 to the moving contact holder 52 and to the contact 53. Should

page_text: this contact be resting against a bar it is of course in connection with it but as shown
it rests against the insulating piece 54.
The second connection is to the insulated screw 55.
The third connection is by the wire 57 to the insulated screw 58 to the contact
spring 59.
The screw 17 is also connected to the insulated contact spring 60 by the
wire 61.
One of the bars namely No. 1 is connected by the wire 62 to the terminal 63
thence by the wire 64 to the insulated contact spring 65. So that when the
spring 65 is raised by the projection 66 of the contact holder 52 striking it, it
makes contact with the springs 59 and 60.
The contact holder 52 is supported by the cord 51 which is wound upon the
reel 50 (not shown in the figure) but is on a continuation of axle 67. In this
particular instance I have shown the weight descending by gravity, its descent
being governed by the person using the apparatus.
The axle 67 is keyed on the reel 50, and to the ratchet wheel 68 which is kept
from turning by the detent 69. This detent has a projection 70. Detent 69
is fixed on another wheel 71 loosely riding on the same axle 67. This wheel is
kept from moving by the detent 72 a projection of which 73 is placed in the
same line as 70. The stirrup 76 is loosely fixed on the pin 77 and can be
raised by the cord 78. The pin 77 is fixed to a bent rod 79 vibrating on the
spring 80. The bottom portion of 79 entering a notch in the catch 81. The
catch 81 is connected to the keeper 82. When the keeper 82 is attracted by
the magnet 19 it pulls 79 with it until the adjustable screw 83 pushes the
plane 84 from it when the catch 81 releases 79 and allows it to return. When
the keeper returns it pushes the plane 85 against 79 which slides along it into
the notch.
When 79 moves it also pulls either the detent 69 by the projection 70 or the
detent 72 by the projection 73 according to the position of the stirrup 76. When
it pulls 70 the moving contact descends the distance of one bar for each pull, the
screw 83 being adjusted to allow one tooth of the ratchet wheel 68 to pass. When
the detent 72 is pulled it allows the ratchet wheel 68 to make one complete
revolution carrying with it the wheel 71 and the detent 69. For every revolution
of the wheel 68 the contact descends 10 bars.
The keeper 82 strikes against the end of the rod 86. 86 can be raised and
lowered by the cord 87. When in the lower position as shown, a projection upon
it catches in the hinge of the bellows 88 and opens them, when raised it passes
free of the bellows 88 and strikes against the hinge of the bellows 89 and
opens them.
As the bellows 88 close, a projection 90 strikes against the catch 91 connected
with the bent lever 92 and moves it thus raising the rod 86 and lowering the
stirrup 76.
When the bellows 89 close a projection 93 strikes against the catch 94 connected
with the contact 22 and presses contact 22 against contact 29.
When the spring 65 is raised by the contact holder 52 it raises the rod 95
which in turn, turns the rod 96 on its longitudinal axis pins upon the latter raise
the catches 91 and 94 allowing them to return into their former position as shown.
METHOD OF USING THE APPARATUS.
If you want to be put into communication with subscriber 62, you tap the
key 2 twice. This closes circuit No. 1 twice. This closes circuit No. 2 twice
expands the bellows 88 and draws the detent 69 twice which allows two teeth of
the wheel 68 to escape and lowers the contact 53 two bars. Allowing an interval
of time, say two seconds, to pass so that the bellows 88 may completely close.
The stirrup 76 is lowered and the rod 86 raised. Then you tap key 2, six times.

page_text: This causes
bellows 89 to be opened and detent 72 drawn back 6 times, when the wheel 68
revolves six times lowering the contact 60 bars which added to the two bars
previously lowered reaches the sixty second bar and is therefore in connection with
subscriber 62.
This closes circuit No. 1 six times and closes circuit No. 2 six times.
During the conversation, the bellows 89 have closed bringing contact 22 against
contact 29. The next time key 2 is tapped it closes circuit 1, that closes circuit
No. 3, which in turn closes circuit No. 4 This brings the raising motor 97 into
work and is not stopped until the weight 52 raises the spring 65 when the catches 91
and 94 are released and the contact 22 returns to contact 21 and the switching
apparatus is in position for another call.
When circuits 3 and 4 are closed relay 35 closes the circuit of the motor 97,
It also allows the clack 99 to
which causes the arm 98 to vibrate up and down.
fall into gear both with the wheel 100 and the arm 98 whereby it turns the
wheel 100 tooth by tooth until the circuits 3 and 4 are opened as above described.
The motor 97 is used in common by all or a certain number of the switching
apparatuses.
It will be noticed that when the contact is lowered the bar belonging to this
particular switching apparatus is cut out of circuit.
That by the connection of the speaking circuit at the various points it clears the
bar of other contacts by sending shunt currents through their switching apparatus
and causing them to be raised or lowered, and also allows this apparatus to receive
like currents from the others.
When the number of subscribers is so great that the number of bars cannot
be conveniently placed on one plane arrange a series of boards one behind the
other with the necessary bars thereon back and front. I continue the axle 61
through a number of reels with their corresponding cords weights moving contacts
and guides and connected with the speaking wire. These reels ride loosely on the
axle but each has a ratchet wheel keyed on the axle adjacent to it. When the reels
are wound up they are held by a detent. When this is raised another falls on to the
ratchet wheel so that the movement of the reel now depends on the axle which in
turn is governed by the switching apparatus.
The choice of the wheel required is made by an additional movement with time
bellows as before. This will raise the detent before mentioned and put the given
reel into gear with the axle.
Or we may use a separate switching apparatus for each board under the control
of one switching apparatus controlled by the subscriber. The release current passing
through to bring them back into the first position.
Escapements may be used instead of the detents before mentioned.
The speaking wire may be used to transmit the release current.
A combination of circuit changer and time bellows may be employed.
The weight 52 travels between the guides fixed to the board, one of them 101 is
shown.
The magnet 31 may be replaced by a time bellows.
The time bellows easily open but by an arrangement of the inlet valve close slowly
at an adjustable speed. They may be made of gutta percha or rubber tissue, oiled
silk cloth or other suitable material.
The springs that close them are 102 and 103.
For the metallic circuit system two contacts on the same holder, and two bars will
be used for each point.
Ona hollows may be used for any number of movements.

page_text: COMPLETE SPECIFICATION.
Improvements in Electrically Controlled Switching Apparatus for
Telephone or Telegraph Exchanges.
I, ROBERT PIPPETTE, of 31 Endymion Road, Brixton Hill, 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 :-
My invention relates to switching apparatus for telephonic, or telegraphic
exchange systems.
The object of my said invention is to enable any subscriber to connect his
instrument, a telephone for instance, to the instrument of any other subscriber with
whom he desires to speak, without the aid of any attendant or switchboard operator
such as is required by the switching systems at present in use.
According to my invention the telephone or telegraph wires of all the subscribers
are brought to one convenient point such as a central station at which station the
temporary connections between various subscribers are made by my improved
switching apparatus. Each subscriber in addition to his ordinary telephone or
telegraphic apparatus is provided with apparatus by means of which he can so
control the switching apparatus at the central station above mentioned that his
telephone or other instrument shall be brought into connection with the instrument
of any other subscriber with whom he wishes to communicate.
In order to attain this end, I preferably arrange that two wires shall be run
from each subscriber's station, one of said wires serving to conduct the telephonic
or other communicating current, the other of said wires carrying the current for
operating the switching apparatus at the exchange. I will call the two wires for
the purposes of this description the telephone line and the switching line respectively.
Each subscriber's telephone line is divided into two branches one branch ending in
a movable contact or contacts and the other branch ending in a fixed contact or
contacts. This latter branch is sometimes provided with a switch for opening and
closing the same, said switch being operated by the first or any current through
the switching line.
If a subscriber wishes to be connected with some other particular subscriber, he
operates his switching line key thus sending a current or currents through the
switching apparatus at the central station which actuates his movable contact so
that it will touch the fixed contact of the other subscriber thus setting up com-
munication between them. At the end of the conversation the first subscriber can
break the connection and restore the movable contact to its normal position by
again sending a current through the switching line; in some cases I arrange that
connection may be broken by either subscriber.
When there is a large number of subscribers I arrange the fixed contacts for the
same in sets and I sometimes provide that each subscriber shall possess as many
movable contacts as there are different sets of fixed contacts. When a signalling
subscriber sends a current into his switching line the central switching apparatus
actuates the movable contact of the first set, and if the subscriber sends another
current along his switching line the movable contact of the second set is operated
and so on.
Thus the first series of currents sent through the switching line picks
out the particular set of contacts with one of which the signalling subscriber wishes
to be connected. I further arrange that a second series of currents sent into the
switching line shall operate the movable contact so as to determine in which ten,
or other suitable subdivision of the fixed contacts in the set previously determined,
the desired fixed contact piece is located. A third series of currents sent through
the switching line actuates the movable contact so that it touches the desired fixed
contact and the signalling subscriber is connected to the telephone line of the
person to whom he desires to speak.
I may transpose so to speak the functions of the second and third series of

page_text: currents above described, that is to say I arrange that the second series shall move
the movable contact over the fixed contacts one by one, and that the third series
shall move the said movable contact over the fixed contacts ten by ten or twelve by
twelve and so on.
In order to make this clear I will take a simple example. For instance if there
are 500 subscribers and any one of them say No. 200 desires to speak with any
other subscriber say No. 354. The fixed contacts are, let us suppose divided into
sets of 100. Then No. 20 sends three currents in rapid succession through his
switching line, the central station switching apparatus then actuates the movable
contact of No. 200 belonging to the third set of fixed contacts. No. 200 now after
a short interval of time sends five currents through his switching line, this by
successive jumps moves his movable contact to the fifth set of 10 in the third set of
100 fixed contacts. After another interval of time No. 209 sends four currents
through his switching line, and this moves his movable contact to the fourth contact
between 350 and 360 of the third set of fixed contacts so that it makes connection
with fixed contact No. 354. If after a similar interval of time subscriber No. 200
or in some cases either of the subscribers No. 200 or No. 354 sends a current
through the switching line contact is broken and the apparatus restored to its
original state and ready for use again.
Referring now to the drawing left with my Provisional Specification I will
describe one form of automatic switching apparatus which I use at the central
station. 1 is the earth wire and represents the earth which acts as a return
common to all the stations. 2 is the contact maker or key at the subscriber's
station, 3 is the switching line and 4 is a battery at the exchange. The switching
line circuit continues through this battery 4, terminal 5, wire 6, and relay magnet 7,
wire 8, terminal 9 and so to earth and is brought back to the other terminal of the
subscriber's contact maker 2. This I call circuit No. 1.
The local circuit at the exchange is formed as follows one terminal of the
battery 10 in the exchange is connected through wire 11, the terminal 12, wire 13,
to the insulated screw 14. then through contact 15 when it touches the screw 14,
through armature 16, insulated screw 17, wire 18, magnet 19, wire 20, insulated
screw 21, spring contact 22, wire 23, terminal 24, wire 25 to other terminal of
battery 10. This I call circuit No. 2.
When the contact 22 touches the screw 39 instead of screw 21 the circuit will
be the same as the last up to screw 17 but then it passes by wire 26 to insulated
screw 27, contact 28, armature 29, wire 30, magnet 31, wire 32, terminal 33,
wire 34, relay 35, wire 36, terminal 37, wire 38, contact 39, spring contact 22, when
it touches contact 39, wire 23, terminal 24, wire 25 to battery 10. Thus magnet 31
and relay 35 are included in the circuit iustead of magnet 19. This I call circuit
No. 3.
Another local circuit is the same as the last up to insulating screw 14 whence it
passes through wire 40 to the insulating screw 41 thence through contact 28 when
it touches screw 41 to the battery 10 as the last circuit. This I call circuit
No. 4.
To save a multiplicity of connections I arrange to have the speaking wire from
each subscriber brought to a bar fixed on the face of the board 42. There will
be as many bars as there are subscribers, some of the bars are shown in section
at 43, 43. They pass under the switching apparatus of each subscriber and are
therefore common to all the apparatuses.
The speaking instrument 45 of the subscriber to whom this switching apparatus
is allotted, say No. 1. is connected to the earth by wire 46 and to the terminal 48
at the exchange by the line wire 47. Thence through the wire 49 to a reel (not
shown) the cord 51 to the moving contact holder 52, and to the moving contact 53.
Should this contact be resting against a bar it is of course in connection with it,
but as shown it rests against an insulating bar 54. The terminal 48 is also con-
nected to the insulated screw 55 by the wire 56 which preferably includes a
resistance which is large in proportion to the resistance of the telephone lines, by

page_text: the wire 57 to the insulated screw 58 and contact spring 59. The screw 17 is
also connected to the insulated contact spring 60 by the wire 61 which wire
includes a resistance similar to that included in the wire 56.
One of the bars namely No. 1 is connected by the wire 62 to the terminal 63
thence by the wire 64 to the insulated contact screw spring 65. So that when the
spring 65 is raised by the projection 66 of the contact holder 52 striking it, it
makes contact with the springs 59 and 60.
In
The contact holder 52 is supported by the cord 51 which is wound upon a reel
which is not seen in the figure but which is on a continuation of the axle 67.
this particular instance I have shown the weight descending by gravity its descent
being governed by the person using the apparatus.
A ratchet wheel 68 which is kept from turning by the detent 69 is keyed on
the axle 67. The said detent has a projection 70 and is fixed on another wheel 71
loosely riding on the axle 67. This wheel is kept from moving by the detent 72 a
projection 73 of which is placed in the same line as the projection 70. The stirrup
or hook 76 is loosely fixed on the pin 77 and can be raised by the cord 78. The
pin 77 is fixed to a bent rod 79 vibrating on the spring 80, the bottom portion of
said rod entering a notch in the catch 81 which is connected to the armature 82.
When the armature 82 is attracted by the magnet 19 it pulls the rod 79 with it by
means of the catch 81 until the adjustable screw 83 pushes the plane 84 from it
when the said catch releases the rod and allows it to return. When the keeper
returns it pushes the plane 85 against the rod 79 which slides along it into the
notch.
When the rod 79 moves it also pulls either the detent 69 by the projection 70
or the detent 72 by the projection 73 according to the position of the stirrup, 76.
When it pulls 70 the moving contact 52 descends the distance of one bar for
each pull, the screw 83 being adjusted to allow one tooth of the ratchet wheel 68
to pass.
When the detent 72 is pulled it allows the ratchet wheel 68 to make one
complete revolution carrying with it the wheel 71 and the detent 69. For every
revolution of the wheel 68 the contact 52 descends 10 bars.
The armature 82 when attracted by the magnet 19 strikes against the end of the
rod 86 which rod can be raised and lowered by the cord 87. When the said rod
is in the lower position as shown, a projection upon it catches in the hinge of the
bellows 88 and opens them against the pressure of a spring 102 when it is struck,
when raised it passes free of the bellows 88 and strikes against the hinge of the
bellows 89 and opens them against the pressure of another spring 103.
Instead
of springs 102, 103 weights or other equivalents may be used.
As the bellows 88 close, a projection 90 strikes against the catch 91 connected
with the bent lever 92 and moves it thus raising the rod 86 and lowering the
stirrup 76. When the bellows 89 close a projection 93 strikes against the catch 94
connected with the contact 22 and presses contact 22 against contact 39.
When the spring 65 is raised by the contact holder 52 it raises the rod 95
which in turn, turns the rod 96 on its longitudinal axis, pins upon the said
rod 96 then raise the catches 91 and 94 allowing them to return into their former
position as shown.
I will now describe the method of using the apparatus.
If a subscriber No. 1 for instance desires to be put into communication with
subscriber No. 62, No. 1 taps his key 2 twice, this closes circuit No. 1 twice thus
energizing relay 7 twice in succession and closing circuit No. 2 which energizes the
magnet 19 and twice expands the bellows 88. This draws the detent 69 twice
which allows two teeth of the wheel 68 to escape and lowers the contact 53 two
bars. As soon as the contact is lowered one or more bars, spring 59 is disconnected
from spring 65 thus breaking the connection between the telephone line and the
fixed bar of the subscriber. After an interval of time say two seconds has
elapsed since circuit No. I was opened the bellows 88 completely close actuating
detent 91 lever 92 and through the cord 78 lowering the stirrup 76 and raising the
Then subscriber No. 1 taps key 2 six times. This closes circuit No. 1
rod 86.

page_text: six times and closes circuit No. 2 six times. This causes bellows 89 to be opened
and detent 72 drawn back 6 times when the wheel 68 revolves six times lowering
the contact 60 bars which added to the two bars previously lowered reaches the
sixty-second bar and is therefore in connection with subscriber 62.
During the conversation, the bellows 89 have opened and closed thus bringing
contact 22 against contact 39 the next time therefore the key 2 is tapped it closes
circuit 1, and the relay 7 then closes circuit No. 3, which in turn by the magnet 31
closes circuit No. 4. These last operations bring the raising motor 97 into action
through the relay 35. The motor is not stopped until the weight 52 raises the
spring 65 which raises the rod 95 which turns the rod 96 and releases the catches 91
and 94. The contact 22 then returns to contact 21 opening circuit No. 4. so that
the switching apparatus is in position for another call. When circuits 3 and 4 are
closed relay 35 closes the circuit of the motor 97, which causes the arm 98 to
vibrate up and down. It also allows the clack 99 to fall into gear both with the
wheel 100 and the arm 98 whereby it turns the wheel 100 tooth by tooth until the
circuit is opened as above described. It will be seen that if either of the sub-
scribers in connection sends a current through his switching line the moving
contact of the first will be disconnected because with the connections arranged as
in the drawing if the second subscriber presses the key in his switching line a
shunt current will pass through his bar to the moving contact of the first subscriber
and will raise or lower the said moving contact of the first subscriber.
The motor 97 is used in common for the switching apparatus of all or of a certain
number of the subscribers.
If the wire 56 and wire 61 be left out the signalling subscriber will be able to
make a disconnection and remove his movable contact from the second subscriber's
fixed bar, but said second subscriber will only be able to make a disconnection by
actuating his own movable contact thus disconnecting his fixed bar from his
telephone line through the spring 59, this however does not remove the first or
signalling subscriber's movable contact from the said second subscriber's fixed bar.
The time bellows is arranged to open easily but by an arrangement of the
air inlet valve the bellows closes slowly at an adjustable speed. The bellows
may be made of gutta percha or rubber tissue, oiled silk cloth or other suitable
material.
The main switching battery 4 is sometimes placed between the terminal 9 and
the earth so that it will be in a wire common to all the switching lines.
When the number of subscribers is so great that the number of bars cannot be
conveniently placed on one plane I arrange a series of boards one behind the other
with the necessary bars thereon back and front I continue the axle 67 through a
number of reels with their corresponding cords, weights, moving contacts and
guides, and connected with the speaking wire. These reels ride loosely on the axle
but each bas a ratchet wheel keyed on the axle adjacent to it. When the reels
are in their normal position each is held by a detent.
When this detent is raised
a pawl falls on to the ratchet wheel so that the movement of the reel now depends
on the axle which in turn is governed by the switching apparatus.
The choice of the wheel required is made by an additional movement with time
bellows as before. This will raise the detent before mentioned and put the given
reel into gear with the axle..
Escapements may be used instead of the detents before mentioned and any
other form of timer or regulator used instead of the time bellows, such as for
instance a pendulum, balance-wheel, fan-wheel, a piston and dash-pot or any other
suitable device.
Instead of a motor for restoring the apparatus to its normal position I may
use a spring or weight which is strained or lifted as the case may be by the
operation of switching.
In the drawings left with my Complete Specification I shew diagrams illus-
trating my improved exchange system and also modified forms of central station
apparatus.

page_text: igure T is a diagram shewing the general arrangement of two subscribers
stations with switching apparatus at a central exchange.
Figure 2 is an elevation of a modified form of switching apparatus for use at the
exchange.
Figure 3 is a sectional plan of part of the instrument taken on the line x, x of
Figure 2.
Figures 4 to 7 are views of details hereinafter more fully explained.
Figure 8 is an elevation of another modified form of switching apparatus.
Figures 9 and 10 are detail views of parts of the apparatus shewn in Figure 8.
Figure 11 is an elevation, and
Figure 12 a detail view of a modification of the apparatus shewn in Figure 8.
Figure 13 is a diagram shewing the switching system I adopt for an exchange
having a large number of subscribers.
Figure 14 is a diagram illustrating a modification of the system shewn in
Figure 1.
Figures 15 to 17 are views shewing various forms of the fixed and movable
contacts as will be hereinafter explained.
Referring now to Figure 1. The two subscribers are denoted by A and B.
101 is the telephone, 102 the telephone line, 103 the earth wire, 104 the switching
line, 105 the contact maker in the switching line at A's station. A's telephone
line is connected at the exchange to A's movable contact 106 and through a
switch 107 to A's fixed contact bar 108. A's switching line is also connected at
the exchange through the relay 109 of A's switching apparatus to the main
battery 110 and thence to earth E by wire 111. B's connections are made in a
similar manner.
When A wishes to connect his telephone to any subscriber, say B for example,
he presses his key 105 thus sending a current through his switching line 104 and
relay 109 from the main battery 110. The central station switch apparatus is then
operated by the relay so that A's movable contact 106 shall be moved so as to
connect with B's fixed contact bar.
I preferably arrange that a current sent through any one of the subscriber's
switching lines, for the purpose of making a connection shall at once break the
connection of the telephone line of the said signalling subscriber to the fixed contact
bar of the subscriber. This is done by means of a switch 107 which is worked in
the same manner as the switch 59, 65 in the drawing left with my Provisional
Specification hereinabove described.
I sometimes dispense with the switch 107 and join the telephone line direct to the
contact bar.
The apparatus at the central exchange which is actuated by the relays in each
switching line is of the kind hereinabove described or of any other suitable
description such as those shewn in the remaining figures of the drawings.
Referring now to Figures 2 to 7, 109 is the relay magnet of any subscriber's
switching line, 115 is the armature thereof which when attracted makes contact
with the screw 116. A local circuit is then made consisting of a local battery and
the magnet 117. The armature 118 of magnet 117 is attracted and acts on the
short arm of the pivoted lever 119 the other end of which engages with a sliding
rod 120. The rod 120 is pulled by the lever in the direction of the arrow
compressing the spring 121 and causing a pawl 122 carried by a spring 123 to slip
over an escapement wheel 124. As soon as the current round the magnet 117 is
stopped, by the subscriber releasing his switching line key, the spring 121 acts to
withdraw the rod 120 causing the pawl 122 to rotate the wheel 124 the
pendulum 125 is thereby set in motion and this will not allow the said rod to regain
its normal position until a suitable interval of time has elapsed, if before the
expiration of the required interval another current is sent round the magnet 117
the rod 120 receives a fresh impulse which causes the same cycle of operations to
be gone through as above described. If after a series of short currents in rapid
succession have been sent round the magnet 117 the subscriber waits for such an

page_text: interval that the rod 120 has time to regain its normal position, another device
comes into action as follows. The spring 123 carries a second pawl 126 which can
engage with a wheel 127. When the wire 123 is pushed by the rod 120 in the
direction of the arrow the pawl 126 runs over the teeth of the wheel 127, but when
the rod comes back so as to regain its normal position the pawl engages with the
teeth and moves the wheel one tooth round against the force of the spring 128.
The wheel 127 is flexibly connected with the lever 129 so that when the wheel is
rotated the lever is moved up or down for a purpose hereinafter explained. It
will be seen however that as long as the rod 120 after having been pushed out is
not allowed to regain its normal position the lever 129 will not be moved and that
when but not until, a long enough interval is made between the successive currents
sent round the relay 109 and magnet 117 the lever 129 will be lowered from its
position to a new position as hereinafter explained. The wheel 127 is provided
with a pivoted detent 130 which prevents it from being turned in the reverse
direction by the spring 128 when the pawl 126 is out of engagement. The tension
of said spring 128 can be adjusted when necessary by the screw 131.
In
In the apparatus now under consideration the fixed contact bars 132 of the
subscribers are arranged in sets on vertical uprights 133, there being for example
one hundred bars in each set. Each subscriber has at the exchange moreover one
switching instrument such as is now being described, said instrument comprising
one or more movable contacts connected to the subscriber's telephone line.
the apparatus shewn in Figures 2 to 7 the number of movable contacts 134 is
equal to the number of sets of fixed contact bars, thus supposing there are five
hundred subscribers on the exchange and that the bars are arranged in five sets of
one hundred, there will be five movable contacts belonging to each subscriber's
switching instrument. The movable contacts 134 are suspended by conducting
cords 135 from reels 136, the subscriber's telephone line being connected to each of
the conductors 135 in any suitable manner. Said reels 136 are preferably screw-
threaded to wind up the cord 135 regularly. In order to reduce the friction I
prefer to secure the reels 136 on hollow axles 139 having a separate pair of
bearings 112 for each reel through which the shaft 137 passes, the reels can thus
not move axially relatively to the shaft but at the same time the said shaft can
very easily rotate relatively thereto. In Figure 4 which is an end view of one of
the reels, is shewn how the reels are when necessary connected to the shaft. 140 is
a lever pivoted on a pin 141 on an arm carried by the hollow axle of the reel, said
lever is provided with a hook 142 at one end adapted to engage with a pivoted
detent 143, and with a tooth or pawl 144 which when the lever is released from the
detent 143 engages with a projection 145 on a wheel fixed to the shaft 137. The
reel therefore is not connected to the shaft and moreover cannot rotate as long as
the detent 143 is engaged with the hook 142. When however the said detent is
operated to release the hook the lever turns, the pawl 144 engages with the
projection on the wheel 145 which is fixed to the shaft 137. The shaft and reel
will then rotate together. That is to say, when the reel is rotated the shaft
rotates also and when the shaft is rotated by any means, any of the reels connected
thereto will rotate with it.
On the armature 118 is pivoted the rod 129 which as hereinbefore mentioned is
flexibly connected to the wheel 127. The rod is proviled with four pins or
projections 146, 147, 148, 149, one of which, according to the position of the rod
which is determined by the wheel 127, can engage with a suitable projection on one
of the swinging levers 150, 151, 152, 153, in a manner which I will now explain. I
so arrange the pins and projections of the levers that only one of the levers can be
operated at a time. In the normal position of the apparatus as shewn in Figure 2
the pin 146 will engage with a projection on lever 150 when the armature 118 is
attracted and pull the said lever aside and this will occur as often as the armature
is attracted that is every time a current is sent through the switching line and
relay 109. But when a longer interval than usual occurs between the successive
currents the wheel 127 is rotated by the pawl 126 and allows the rod 129 to drop

page_text: such a distance that the pin 147 can engage with the projection on the lever 151,
the pin 146 dropping out of action. The lever 151 will then be moved every time
a current is sent through the switching line. After another comparatively long
interval of time is made between the currents during which time the wheel 127 is
further rotated, the pin 148 comes into action and operates the lever 152; all the
other levers being out of action. At the end of the conversation during which
time the wheel 127 has rotated a little farther the pin 149 comes opposite the
projection on the lever 153 and when the switching off or release current is sent
through the switching line the lever 153 is operated. A suitable shape for the
swinging levers is shewn in Figure 5 the pins on the rod 129 being clearly shewn in
Figure 3, but do not confine myself to the shape shewn. The swinging levers
may be pivoted on axles or hung by springs in a manner similar to that in which a
pendulum is hung. I arrange that the suspension will assist the weight of the lever
in bringing same back to its normal position or in the case where pivoted levers are
used I provide a small spring for the same purpose. It will be understood now
that the first series of currents sent through the switching line moves the lever 150
a certain number of times corresponding to the number of separate currents sent;
also if after certain intervals a second and third series of currents be sent through
the line the levers 151 and 152 will be respectively operate as many times as there
are currents sent through the line and that when after another interval a final
current is sent through the line the lever 153 will be operated.
The shape of the lever 129 and the disposition of pins thereon may be varied so
as to alter the order in which the swinging levers come into action, also the height
of the projections on the said swinging levers may be varied for the same purpose.
The lever 150 is provided with a spring arm 154 carrying a pawl 155 which
engages with a rack 156 formed on a sliding bar 157. The said sliding bar is
provided with suitable projecting arms 158 arranged at such intervals along its
length that the said arms in succession come opposite the levers 143 which operate
the reels 136, when the bar is moved in the direction of the arrow, against the pull
of the weight 179. The bar 157 is prevented from returning by the detent 178.
When the lever 150 is operated once, the bar 157 is moved in the direction of the
arrow by means of the pawl 155 and rack 156 and I arrange that the first swing of
the lever shall move the bar so far that the first of the series of arms shall come
opposite the lever 143 appropriated to the first reel of the series. If now by any
means the bar 157 were rotated the arm 158 would strike the detent 143 and
release the first reel which with the shaft 137 would be able to be rotated and the
movable contact of the subscriber would be moved over the first set of fixed
contacts whenever the shaft 137 was allowed to rotate. The other reels on the
shaft would not be released from their respective detents 143 and consequently
would not be able to rotate neither would they be connected with shaft 137 so that
said shaft could rotate freely. If two currents in rapid succession were sent round
the switching line the lever 150 would be operated twice and the bar 157 moved so
far that the second of the arms 158 would be brought into position ready to operate
its detent 143 and release the second reel. It is easily seen therefore that the reel
supporting the movable contact at the top of the 1st, 2nd, 3rd or any other set of
fixed contacts would be released in readiness for the movable contact to drop
according to the number of times the lever 150 was operated.
On the end of the shaft 137 is secured an escapement wheel 160 having 10 teeth.
The shaft also carries a rotatable arm 161, at the other end of which is pivoted a
suitable escapement 162, of the anchor type for instance. The escapement. 162 is
adapted to be operated by the lever 151 so as to allow the wheel 160 and with it
the shaft 137 to rotate one tooth of said wheel at a time.
rotation of the shaft 137 and whichever of the reels 136 is connected with it, one
I arrange that the
tooth of the wheel 160 at a time shall lower the
between the centres of two fixed contact bars.
the lever 151 is moved by the attraction of the
of the subscriber will be moved one contact
movable contact through the space
Hence it is seen that every time 5
armature 118 the movable contact
further down. The lever 151 is

page_text: arranged to rotate the bar 157 so as to release any particular one of the reels 136
from its deteut 143 as follows. The bar is arranged to slide through a collar 163
but not to rotate therein, the said collar is provided with a projecting arm 164 which
engages with a ledge or projection 165 on the lever 151 as long as the said lever is
in its normal position, but when the lever is moved the arm 164 being released
rotates the collar 163 and with it the bar 157, thus moving the arms 158, and also
if any one of the arms is opposite its detent 143, the said detent will be operated
thus releasing a particular reel 136.
On the top of the bearing 138 of the shaft 137 is pivoted another escapement 167
which prevents the arm 161 turning round the shaft 137 This escapement 167
can however be operated by the lever 152 so that every swing of said lever allows
the arm 161 to turn once round and so lower one of the movable contacts over ten
of the fixed contacts. The said escapements 162, 167 are preferably maintained
in their normal position by springs which are not shewn in the drawings.
If a certain time after the second series of currents which operates the lever 151
has been sent through the switching line, a third series of currents be sent through
the line the rod 129 will have dropped and the lever 152 will now be operated as
many times as there are currents sent through the line. After another interval of time
the release or disconnecting current is sent through the switching line, the rod 129
having dropped lower, the ultimate effect of this current is to operate the lever 153.
A projecting arm 168 on the lever which until then had been resting on an
insulated piece 169, see Figure 7, now is moved so as to make contact with a
spring 170 this puts a motor into action which turns a shaft 171 having a gear
wheel 172 at the end thereof. The forked end 173 of the lever which is formed
with a spring and engages with a sliding collar 113 fixed to a gear wheel 174, moves
the said gear wheel along the shaft 137 so as to gear with the wheel 172, the gear
wheel 174 being able to slide along but not to rotate relatively to the said shaft.
The lever 153 is kept out of its vertical position by the contact spring 170 so that
the two wheels 172 and 174 are in gear until the contact is broken. In order to
shew how this happens I will explain the function of the reel 159 which I call the
pilot reel. This pilot reel is like all the other reels 136 but is firmly secured to the
shaft. It is moreover provided with a weight 175 which may assist the movable
contacts 134 in furnishing the motive power for rotating the shaft 137 during the
setting up of a connection. The travelling weight 175 is arranged to break the
connection between the telephone line of the signalling subscriber and all the fixed
contact bars of that subscriber in the exchange as herein before referred to in the
description of Figure 1. When the weight 175 is wound up by the motor through
the medium of the gear wheels 172 and 174 it of course raises that movable contact
which happens to have been in use. As soon as the weight has nearly reached the
top it strikes against the forked end of a rod 176 which raises the detent 130 allowing
the spring 128 to raise the rod 129 by rotating the wheel 127 backwards, and
through an arm 177 raises the detent 178 which in turn raises the pawl 155 and allows
the bar 157 to be retracted by the weight 179. Moreover the rod 176 by means of
an arm 180 raises the arm 164 thus rotating the shaft 157 till the detent 143 cau
re-engage with the hook 141 thus releasing the reel 136 which has been in use, from
the shaft. The arm 180 finally breaks the motor circuit by raising the spring 170)
thereby allowing the lever 153 to swing back and its projection 168 to come under
the insulating block 169. Everything will now be restored to its normal position as
shown in Figure 2.
I will now give an example to shew the method of using this apparatus. I will
suppose that there are between 500 and 600 subscribers and that their fixed contact
bars are arranged in five sets of one hundred in each set. Then each subscriber is
provided with an instrument such as above described which contains five reels such
as 136 in Figure 2 and five movable contacts. If a subscriber say No. 100 wishes
to call say No. 432 he first taps his switch line key four times this moves lever 150
The fourth
four times which brings the fourth catch 158 opposite its detent 143.
movable contact of No. 100 is now ready to be put in action. After waiting say one

page_text: second No. 100 taps his key twice this operates lever 151 twice. The first swing of
lever 151 allows the arm 164 to drop thus turning the bar 157 and putting the fourth
reel 136 in connection with the shaft 137. The lever also through the escapement 162
allows wheel 160 to rotate two teeth under the action of weight 175 and thus rotates
the shaft 137. The movable contact 134 of No. 100 thus descends two bars. After
another interval of one second No. 100 taps his key three times this operates lever 152
three times and by escapement 167 allows the arm 161 and shaft 137 and reel 136
to turn three complete revolutions this drops the movable contact 30 bars. The
movable contact therefore is now resting against bar 432 and No. 100 is connected
direct to No. 432. After the conversation is finished No. 100 taps his key once more
and this operates lever 153 which restores the apparatus to its normal condition as
above described.
In a modified form of this apparatus I arrange that there shall be only one reel 136
with one movable contact said reel being arranged to be moved along the shaft 137
its movement being arrested when the movable contact is over the right set of fixed
contacts. Such an arrangement is shewn in Figures 8 to 10. The travelling reel 136
is mounted in bearings on a carriage 181 shewn in plan in Figure 9 and in elevation
in Figure 10. Said carriage is provided with a fork 182 in which the movable
contact 134 slides for the first part of its descent. Said movable contact is thus
prevented from swinging when the reel is moved axially. The reel is arranged to
slide but not turn on the shaft 137 and is moved along by means of a cord 184
attached to the carriage at one end the other end thereof being secured to a descending
weight 185, the carriage is provided with friction wheels 183 which bear against the
base board 186 of the instrument. The reel is maintained in its normal position by
means of a catch 187 on the end of a pivoted lever 188. The bar 157 is moved by
means of a spring supported pawl 155 fixed to the first swinging lever 150 as described
with reference to Figures 2 to 7 and the arms 158 on said bar are arranged to be
brought in succession opposite pivoted stops 189. Thus one swing of lever 150 will
move the bar 157 so as to bring an arm 158 opposite the first pivoted stop 189; a
second swing will bring an arm opposite the second stop lever and so on. The lever 188
is arranged to be operated when the lever 129 is lowered from its position of
engagement with the swing lever 150 to its position of engagement with lever 151
as follows: The arm 164 is normally held by the pivoted detent 230, and said detent
is so connected by the spring arm 231 with the stop 232 on the cord 233 that in the
position shewn the arm 164 is held by the detent. When the cord 233 lowers the
lever 129 the spring drops and the detent thereby releases the arm 164. The said
arm 164 drops striking the lever 188 and releases the reel 136 at the same rotating
the shaft 157 in its bearings; one of the arms 158 then strikes the upper part of the
lever 189 to which it is opposite and the lower part of said lever is thereby brought
into position to arrest the axial movement of the reel 136 by engaging with a
projecting portion 190 of the carriage. The escapement devices for lowering the
movable contact are similar to those described with reference to Figures 2 to 7 with
the exception that I preferably arrange that the lever 151 shall work the escape-
meut 167 instead of the escapement 162 this latter being worked by the lever 152.
By this means the movable contact is lowered through a distance equal to ten bars
when it reaches the first bar of the series.
The arrangements for restoring the instrument to its normal condition when
disconnection is desired are the same as above described with reference to Figures 2
to 7 with the following additional device for moving the reel 136 and carriage 181
back along the shaft 137. For this purpose the carriage is connected by a cord 191
to a shaft 192 having a gear wheel 193 fixed thereon. Said shaft and gear wheel
are supported in bearings fixed to a spring 194. When the pilot weight 175 is
moving upwards through the upper portion of its travel it presses up the spring 194
which catches in a pivoted detent 195. The weight 175 then drops again in a
manner hereinafter explained, but leaves the spring behind, the gear wheel being
still in engagement with the wheel 172 on the motor shaft. Thus the cord 191 is
wound up and the reel 136 drawn backwards along the shaft 137 until it strikes the

page_text: end 196 of the detent 195, this releases the spring and allows the wheel 193 to drop
out of engagement with the wheel 172. 1 arrange that the spring 194 and
detent 195 shall form a switch in the motor circuit said switch being in parallel
with the switch formed by the spring 170 and lever 153 so that although the
connection is broken at the latter switch by the rising of the arm 180 as herein-
before described yet the motor circuit is maintained through the spring 191 and
detent 195 until the reel 136 is brought to its normal position.
In Figure 11 I show another modification of the instrument in which the
longitudinal movement of the bar 157 is dispensed with. The said bar is furnished
with arms 196, 197, 198, 199, 200 and so on. Said arms point alternately in
different directions. Thus arms 196, 198 200 are in one plane while arms 197,
199 are in another plane. I provide a bell crank lever 201 which takes the place
of lever 150, said lever 201 being so arranged that every time the armature 118 is
attracted by magnet 117 the lever 129 being in its uppermost position the bar 157
shall be rocked or partially rotated on its axis backwards and forwards. The
carriage 181 of the travelling reel 136 has a projecting part 202 as shewn in
Figure 12 which is an end view of the said carriage and reel; said projecting part
is adapted to engage with the arms 196, 197, and so on, and has a continuous pull
exerted on it by the weight 185. Hence when the bar 157 is rocked as above
described the reel 136 is drawn along the shaft 137 escaping the arms 196, 197 and so
on, one at a time. For instance when the lever 201 is operated it first partially rotates
the shaft 157 in one direction, the arm 196 is thus moved out of the way of
projection 202 of the carriage which moves along but is arrested by the arm 197.
When the bell crank lever 201 moves back it rotates the shaft 157 in the opposite
direction, this moves the arm 197 out of the way of the carriage which moves on
until it is stopped by the arm 198. Thus for every to and fro movement of the
lever 201 that is to say every time the armature 118 is attracted and moves the
lever 129, the carriage moves forward the space between two of the arms 196,
197 etc.
I so arrange the spaces between the said arms that after the projection on the
carriage has escaped past the first two of the arms, the movable contact shall be
exactly opposite the first set of fixed contacts, and after carriage has moved through
another short distance, the projection 202 escaping two more arins, the movable
contact shall be opposite the second set of fixed contacts and so on.
The arrangements for restoring the instrument to its normal condition are the
same as hereinabove described with reference to Figures 2 and 8, with this exception
that the forked end of the rod 176 is above the spring 194, so that the said spring
is retained by the detent 195, the rod 176 is kept in a raised position until the
reel 136 liberates it by moving the detent 195. While in this raised position the
arm 234 of the rod 176 engages with a pin 235 on the rod 157 and rotates said rod
on its axis so that all the arms 196, 197, 198 and so on are taken out of the path of
the returning reel 136. When the reel 136 strikes the detent 195, it releases the
rod 176 and the spring 194, the parts then assume their normal position as shown.
In all the instruments wherein I provide a pilot wheel 159 with a weight 175 the
rising of which operates the various parts to restore the same to their normal
positions it is necessary that the said weight should ascend at first higher than its
normal position so as to complete its operation on the various levers and should
then descend so that the rods 176, 177, 180 shall be out of the way when a
connection is being made again. For instance, referring to Figure 2 it is obvious
that if the rod 176 were always pressing on the end of the detent 130, said detent
would not engage with the wheel 127 until the weight 175 dropped a little and so
would be useless. It is therefore necessary that the rod 176 should ascend a short
distance too high and then drop to its normal position. I accomplish this as follows:
While the reel 159 is turning backwards with the shaft 137 and winding up the
pilot weight 175, the pin 166 in the wheel 160 ultimately engages with the arm 161
of the escapement 162 and forces it to rotate. Said arm slips past the escape-

page_text: ment 167 during every revolution until when the weight has reached its normal
position the arm is just past the front pallet 203 of said escapement, the weight
however still ascends, there being nothing to prevent it, and actuates the various
restoring levers finally breaking the motor circuit and putting the wheels 172, 174
out of gear.
The weight now falls again, the arm 161 being rotated by virtue of
the escapement 162 engaging with the teeth of wheel 160 until said arm is stopped
by the front pallet 203 of the escapement 167 when the weight is in its normal
position again.
When the exchange contains a very large number of subscribers I arrange what
I will call a supplementary circuit changer in combination with a suitable number
of switching instruments of the character above described, for each subscriber.
For instance if there are five thousand subscribers I may first divide them into
five sets of one thousand each, each set being connected by one switching instrument.
Hence instead of one switching instrument at the exchange each subscriber will
have five instruments one for each division of the subscribers, the exchange will in
fact consist of five smaller exchanges grouped together. Each subscriber will
moreover be provided with a circuit changer at the exchange which will operate to
connect his switching line to one of his five switching instruments.
Figure 13 which I will now describe is a diagram shewing part of the apparatus
appropriated to one subscriber.
215 is the switching line from one subscribers' station which by means of a
relay 109 or directly operates the circuit changer 216. The circuit changer is of
simple construction and by means of an electromagnet 217 and a pawl 218 and
ratchet wheel 219 is arranged to give a step by step motion to an arm 220 which
moves over a series of contact points 221. Every time the armature of the electro-
magnet is attracted the arm 220 as will be readily understood, moves from one
contact point to the next. Thus if three currents are sent in rapid succession
through the switching line the arm 220 moves to the third contact point and so on.
If a longer interval than usual is made between successive currents a timing
device such as hereinbefore described operates to cut out by means of a switch 222
the magnet 217 and the current from the battery now operates the magnet 117 at
one of the switching instruments which has been brought into circuit by the circuit
changer. The timing device also operates a switch which disconnects the signalling
subscriber's telephone line from his fixed bar. The switching instruments are of
the kind hereinabove described and the motor provided to restore them to their
normal condition also replaces the supplementary circuit changer in its normal
position, by means of a magnet 223 in the motor circuit the armature of which
operates the switch 222 and releases the ratchet wheel 219. Said ratchet wheel 219
being rotated back again by means of a suitable spring.
As an example if a subscriber wishes to be connected to a subscriber in the
fourth group of subscribers, he first sends four currents in rapid succession through
his switching line this operates the circuit changer so that if he makes a pause and
then sends a current through his switching line the last current will operate that
switching instrument which is adapted to connect his telephone line to a subscriber
in the fourth group. The subscriber now sends currents through his switching line
to operate his switching instrument as hereinabove described with reference to
other figures of the drawings.
In Figure 14 I have shewn a modification of the system above described with
reference to Figure 1 and to the drawing left with my Provisional Specification.
According to this system it is rendered possible for either of the connected
subscribers at the end of a conversation to operate the central station apparatus so
that the movable contact of the first or signalling subscriber shall be brought to its
normal position. The drawing is lettered to correspond with the drawing left with
my Provisional Specification. In this modification each subscriber is provided with
a supplementary fixed bar 43 which is joined to the spring 65" of similar character
but insulated from spring 65. Also each movable contact block is provided with

page_text: an additional contact spring 53", which is insulated from the ordinary contact
spring 53 and is adapted to connect with the supplementary bar 43" of a subscriber
when the ordinary contact 53 connects with the ordinary fixed bar 43. This
second contact spring is connected by an insulated wire to the screw 55.
The only difference therefore between the connections shewn in Figure 14 and
those shewn with the drawing left with my Provisional Specification, are as
follows: The spring 60 is adapted to connect to the supplementary spring 65"
which is connected to a supplementary fixed bar 43 and screw 55 is connected to
the supplementary contact 53 instead of to the subscriber's telephone line 47, the
wire 56 being entirely removed.
It will be easily seen from an inspection of the figure supposing A's movable
contact to be moved so that contact 53 touches bar 43 that is to say A's telephone
line is connected to B's line then A's contact 53° touches bar 43º. If B now
operates his key 2 sending a current round the relay 7 the armature is attracted so
that 15 and 14 will be joined a current will then flow from battery 10 through
wire 15, wire 14, switch 60, 65 (which is closed since B's movable contact is in its
normal position) supplementary bar 43", contact 53° to screw 55, wire 15 (which is
in contact with screw 55 as A's relay No. 7 is not in operation) to A's magnet 35
operating the motor 97 to draw up A's movable contact and back to battery 10
again. This circuit is shewn in dotted lines in Figure 14. Thus B can by
operating his key 2 actuate and disconnect A's movable contact from his fixed bar.
In Figures 15, 16 and 17 I have shewn how I may construct the sets of fixed
contact bars. 133 is a backing, 132 are the contact bars.
When the backing 133 is of metal I place suitable insulation 207 between the
bars and the backing and provide the screws 208 which secure said bars with
insulating bushes 205 as shewn in Figure 17.
209 are guides for the movable contacts suitable constructions of which wherein
the parts are made of wood or metal or other material are clearly shewn in
Figures 15 and 16.
The fixed contact bars 132 are preferably continued in one length right through
the switch room in a direction perpendicular to the base boards of the instruments
which are arranged in parallel planes one behind another. The planes of said
contact bars may be inclined or horizontal.
In the cases where the movable contacts are traversed across the sets of fixed
contacts the top bar or top of the board is bevelled off as shewn at 211 in Figures 8
and 12.
The moving contacts are clearly shewn in Figures 2, 8, 10, 11 and 12. Those
shewn in Figure 2 are very simple consisting of a suitable base 134 preferably of
insulating material with a springy piece of brass 210 secured thereto and forming
the actual contact. Said piece of brass may be connected to the cord 135 or may
simply connect the one of the fixed bars against which it happens to be resting to
one of the guides 209 which guide is connected to the telephone line of that
subscriber to whom the movable contact belongs. I sometimes use two or more
movable contacts on the same insulating holder for metallic circuit switching or in
the system shewn in Figure 14 that is to say for two or more circuits.
Both the fixed and moving contacts will be made of some conducting material,
metal or alloy, such as iron, copper, tin, lead, steel, brass, or pewter or other suitable
material, and may be plated or covered with copper, tin, platinum, gold, silver,
nickel, or other suitable material to lessen oxidation by any suitable process as
electro-plating, amalgamation, sweating on with solder, or dipping in molten
metal.
Both the fixed and moving contacts may take the forms of bars, planes, plates,
rods, studs, pins, rings, tubes, cylindrical bars, wheels, brushes, springs, discs or the
like and may be made in any suitable shape.
When using the instruments shewn in Figures 8 and 11, I prefer, in order to
economize space to arrange two sets of fixed contacts 132 on the same backing 133.

page_text: The movable contact is then furnished with two brass contact pieces 210 so as to
make contact with either set of fixed contacts. The construction of these movable
contacts is clearly shewn in the drawings above mentioned and need not be further
described.
I have herein described my improved instruments as applied to telephonic
switching, but they are obviously applicable to telegraphic or any other kind of
electric signalling apparatus.
It will be understood that instead of using relays on the switching lines I can
work the instruments direct also I may dispense with the switching lines and make
other modifications in detail without departing from the nature of my invention.
For instance instead of using movable contacts which are allowed to fall down past
a series of fixed bars, I sometimes arrange that the reels 136 or their equivalents
shall actuate one or more radial arms which is or are moved by the rotation of the
reel over a series of contact points or bars belonging to the various subscribers.
Also I can arrange other devices for connecting the swinging levers, or their
equivalent with the armature or moving part by which they are actuated instead of
using the connecting lever or link 129. In the case where swinging levers are used
I may employ a separate link secured to each lever said links being successively
brought into action by means of the timing device.
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 I
claim is :-
1. A telephonic or telegraphic exchange system in which any subscriber can put
his line in connection with that of any other subscriber by sending two or more
series of currents in the same direction through a single switching line to a central
switching apparatus, the successive currents in each series being separated by an
interval of time which is less than a predetermined time interval, and each series
being separated from the preceding by an interval of time which is longer than
the said predetermined time interval.
2. In a switching instrument by means of which one subscriber to an exchange
system can from his station connect his line to that of any other subscriber in the
system, a timing device which, when an interval of time exceeding a definite limit
is allowed to elapse between successive currents sent through the said instrument,
alters the disposition of parts thereof, so that the first current sent through after
such interval operates a different set of levers or moving parts from that operated
by the last current sent through just before said interval, for the purpose
specified.
3. In a switching apparatus of the kind herein described a lever or rod which
connects one moving part such as the armature of an electromagnet with different
levers or moving parts in succession according to the number of separate series of
currents sent through the apparatus, substantially as, and for the purpose,
specified.
4. The method of changing the relative positions of one or more parts of the
instrument by means of a timing device or timing devices, substantially as set
forth.
5. In a switching apparatus of the kind herein described, the method of trans-
mitting the mechanical notion of one moving part of the instrument to any one of
two or more moving parts of the same by means of a movable connection capable
of being moved from one to the other, for the purpose specified.
6. A telephone exchange system arranged substantially as described with
reference to Figure 1 or to Figure 13 or to Figure 14 of the drawings left with
my Complete Specification, and operating as specified.
7. A telephonic switching apparatus constructed substantially as described
with reference to Figure 2 or to Figure 8 or to Figure 11 of the accompanying
drawings.

page_text: 8. A telephonic switching apparatus constructed substantially as described with
reference to the drawing accompanying my Provisional Specification, and the
described modifications thereof.
Dated this 18th dow of Tal 1000
ROBERT PIPPETTE.
Haseltine, Lake & Co.,
45, Southampton Buildings, London, W.C., Agents for the Applicant.