Improvements in Automatic Exchange Systems and Apparatus for Telephonic and other Electrical Communication.
Year: 1895

page_text: Date of Application, 1st Apr., 1895
Complete Specification Left, 4th Jan., 1896-Accepted, 8th Feb., 1896
PROVISIONAL SPECIFICATION.
Improvements in Automatic Exchange Systems and Apparatus for
Telephonic and other Electrical Communication.
RIDLEY JAMES URQUHART of 57 Barton Arcade, Manchester, Consulting
Engineer and Patent Agent, do hereby declare the nature of this invention, which
has been communicated to me by Ward Decker of Owego, County of Tioga, State
of New York, United States of America, Electrician, to be as follows:-
--
My invention relates to automatic exchange systems and apparatus for tele-
phonic and other electrical communication.
Its object is to do away with the use of employees and managers at the central
station, and, therefore, to reduce the operating expenses. The special object of
the invention is to simplify and otherwise improve the present systems having a
similar object.
By "telephone lines" in the following description, I mean those lines which are
to be connected by the automatic central exchange device. They may be used
also to connect circuits by telegraph systems; or in systems of seeing by electricity.
It is applicable to any system in which apparatus at one sub-station is to be placed
in electrical communication with apparatus at another sub-station, through a device
located at an intermediate station.
I find it convenient to use the words "calling lines" to indicate those lines
which are used for operating the switch board. Sometimes I employ for the
central station switch-board merely the words "the central station," and the
Οι "sub-stations.”
outlying station I call either "subscribers
"
All the details of the invention are represented in the accompanying drawings.
Generally stated, the figures show the invention mostly in diagram, so as to
bring out more clearly the individual elements which comprise the invention as a
whole.
Figure 1, is an elevation of the apparatus employed at the sub-stations for
operating the central station device, which may be called the switch-board, while
the device shown in Figure 1, may be called a switch board transmitter.
Figure 2, is intended to represent the electric circuits from one sub-station to
another sub-station through the central station board, which is represented as to its
necessary elements in perspective.
The transmitter in Figure 1, is represented twice in Figure 2, but only as to
mere outline of one or two of its elements. The switch-board shown is adapted to
put eight subscribers into electrical communication.
Figure 3, is a similar view to that shown in Figure 2, for illustrating how two
subscribers on one line may be connected to one subscriber on another line.
In Figure 2, only a portion of the switch-board is shown; but in Figure 4, is a
perspective view of all the connecting bars, ratchet wheels, and switches, as they
stand at rest on an eight subscriber exchange.
Figure 4A, shows the system of cards at the sub-stations.
Figure 5, shows a modification of means for operating the ratchet wheels. It is
a perspective view.
All the
Figure 6, is a modification of an eight subscriber switch board in end view. The
ratchet wheel has twice the number of teeth, and has two contact arms.
contact bars can therefore, be arranged on one side of a circle.

page_text: Figure 7, illustrates the application of a relay for the operation of the switch
board, so that the current passing over the main line between the several stations
need not be very much, because the local current which is operated by the relay
may be caused to do all the work.
"
Figure 8, shows a modification of the arrangement shown in Figure 7, whereby
polarized relay is employed, and whereby the number of sub-stations may be
multiplied without materially increasing the intricacy of the central station
switch-board.
I will first describe the invention by particular reference to Figure 1.
:
A, is a shaft capable of rotation in either direction and rigidly mounted thereon
is the segmental wheel, B, with eight raised surfaces C¹, C2, C3, C4, C5, C6, C7,
and C³, and on one side the depression D, is considerably more in depth than the
notches X on the opposite side. E, is an arm held in position on the wheel B, by
the screw F, and is adjustable sideways by the screw F, and slot G. H, is an arm
pivotted at J, and held against the stop K, by the spring L, so that the outer end M,
is movable only to the left, as viewed from the centre or shaft A. N, is an arm of
insulating material, while (), is a strip of conducting substance mortised into the
side. The arm, N is pivoted at, P, and is held normally in position as shown
pointing toward shaft A by the flexible strip or spring R, working between the
two pins, S and S¹. T, is a cord or chain, one end fastened around the drum U,
which is fastened rigidly on the shaft A, and the other end fastened to the spring V,
which is fastened to the frame work at W. The tendency of the spring being to
always bring the arm H, against the stop Y. Z, is a binding post connected to the
conducting strip O, and Z', another binding post connected through the frame work
to the teeth C¹, C², etc. The point 5, is simply a normally open contact point,
whose use will be explained later. 6, 7, 8, 9, 10, 11, and 12, are holes the proper
size to hold the plug 13. The shaft A, carries the gear wheel a, engaging with the
pinion a', having a fan wheel all, all so arranged in such a manner as to cause the
shaft A, when revolved by the action of the spring V, and chain T, to move at a
comparatively slow rate of speed. Also, rigidly attached to shaft A, but not
shown, is a crank, by the action of which shaft A, is turned by hand in a direction
contrary to the pull of the chain and ring When normally at rest, arm H, rests
against stop Y, and arm N, points directly toward shaft A, as represented in the
drawing. On revolving shaft A, together with its wheel and arm attached, in a
direction to the right, as seen in looking at the drawing, arm N, is forced
backward, and when arm H, passes the hole 6, arm N, drops into the first notch X,
and by its end resting against C, prevents wheel B, from turning backward.
This action continues on all the notches, until the last one C³, has passed, when
the arm N, drops into the depression D, and once more points directly toward the
shaft A. While said arm N, has been making engagement with the wheel teeth,
it has been touching said teeth only by its insulated side. The wheel B, in its
first movement is carried around so far that the arm can entirely escape from the
teeth and rim to its radial position in reference to the center A, in order to be
ready for the reverse movement of the wheel B, which will throw the arm N, in
the position shown dotted. Of course, the wheel B, need not be turned around in
its first or forward movement any further than simply to let the arm N drop into
its radial position after the teeth have all passed it. Now if shaft A, is released,
it starts to travel back slowly by action of spring V and retarding wheels, and
thereby arm N, is thrown in the opposite direction, as shown by the dotted lines in
the drawing. The teeth on wheel B, one after the other, strike, first upon the
conducting strip O, and then upon the insulating body of arm N, causing by
these alternate makes and breaks, successive impulses to travel over the line:
attached to the binding posts Z, and Z. Always supposing a battery or
other source of electricity in circuit with said lines. Supposing, that before
operating the transmitter, plug 13 to have been placed in some one of the
holes, for example, in hole 10. In turning by hand in the direction towards
the right, arm H, would spring past the plug 13 in hole 10, but on returning,

page_text: going in the opposite direction, arm H, woull not spring by, but would cause
the entire stoppage of all the moving parts. Three impulses would have gone
over the circuit. This circuit is attached to an operating magnet at the central
station, and these impulses cause a switch at sai central station, connected by
another wire, to a telephone or other communicating instrument, located at the
same sub-station as the transmitter, to have moved three contacts in advance, as
will be explained hereafter, and come in contact with a contact bar occupied by
a switch from another sub-station, thus putting the two sub-stations in electrical
connection with each other, and this connection will be maintained until plug 13,
is removed from hole 10. By the stoppage of the moving parts by the plug 13, in
the hole 10, communication may be carried on telephonically with a distant station
until the two parties have finished their conversation. Then the plug 13, may be
removed from the hole 10. When that occurs, wheel B continues its rotation,
making five more contacts with the conducting plate O, and by so doing makes its
svitch at the central station complete an entire revolution, and come to rest at the
starting point. The whole system is now ready for use for the purpose of
communicating again with the same or a different station, and the operation if
repeated would be substantially the same as above described, except that the
plug 13, would be put into the proper hole according to instructions conveyed by
the cards shown in Figure 4 and hereinafter described. Further, in order to
understand the above mere outline of communicating with a distant sub-station,
the reader is referred to matter.stated hereinafter, where the remaining elements
of the central station named in the operation are indicated by reference letters.
In the last direction that wheel B, moved, the arm N, also makes engagement
with the teeth C, and prevents backward motion, so that in operating, nothing but
the complete number of impulses can be sent, as arm E, must be moved past all the
holes before it can return, and when started back must come to the starting point
before another call can be made.
If, from accident the subscriber's switch at the central station should come to
rest on the wrong bar, for instance, five in advance of his own, he, ascertaining by
calling the said fifth subscriber, the number he is on, and finding it five, and
knowing that three more complete the cycle of eight, sends three impulses over
the calling line by the key 5, and brings his switch at the central station to the
proper position. It is evident that any subscriber on any size of exchange, can
re-set his switch, if disturbed, in the same manner.
The insulated pawl N, has a notch N¹ at the end for the purpose of causing the
tooth as soon as it has passed off the conducting strip O to slip off the upper
surface, so that it cannot be moved, backwards and by making contact again send a
wrong impulse, while the recessed part of the insulated pawl prevents it from
striking against the next tooth. Also the plug holes are so that the arm H, on
striking the plug 13, will bring a tooth on the wheel B, in such a position
that the notch N', in the end of the pawl N, will prevent backward movement,
and will also prevent the conducting strip O, from making contact with the next
tooth.
This also prevents the battery from being maintained in circuit during the
operation of the telephone or other instrument.
In Figure 2, representing two subscribers' connections on an eight subscriber
exchange, A1, A2, A3, A4, A5, A6, and A8, are stationary contact rods or bars.
X and X2 are ratchet wheels with eight teeth apiece, into which the pawls C₁
and C, play. The wheels' backward motion is prevented by the springs DI and D²,
engaging with said teeth. The springs D' and D2 serve as conductors from the
wheels X' and X2, to the telephone lines E' and E2, attached to the sub-stations L,
and M, respectively. M and M2 are arms with spring contact ends Q and Q
and they are rigidly attached to, and in electrical connection with X and X2
which revolve on, but are insulated from the shaft N. Each ratchet wheel and
arm is insulated from the other ratchet wheels and arms. The other end of the
G' and Gare
circuits E and E* are grounded at F1 and F2, respectively.

page_text: electro magnets controlled by transmitters H¹ and H2, and batteries J and J2,
over the lines K' and K2, respectively. G' and G2 are also connected to the common
ground L.
Batteries J¹ and J are connected to ground F1 and F2, respectively.
Contact ends Q1 and Q2 are adapted to make contact, one after the other, with
each stationary contact-bar in the A. series. When normally at rest, the contact
rod Q lies in contact with contact rod A2 while contact rod Q2 is in contact with
the contact rod A'. As shown in the drawing, the sub-station I has connected
itself to the sub-station M, by moving his contact bar M', seven bars in advance,
or to A¹, as explained hereafter. Consequently both arms are in contact with
rod A¹.
Figure 3, shows the same general connections, and is designated by the same
letters as in Figure 2, with the exception that one of the stationary bars A, is
permanently connected to the common ground 1, and two sub-stations O, and L,
are shown connected on the same line.
Figure 4, as before explained, shows in perspective, all the contact arms of an
eight subscriber exchange at rest in a spiral row, each in contact with a
separate bar.
"
In Figure 5, c represents an arm pivoted or journalled at 1, and held when at
rest, against the stop s, by the spring t. Pivoted on the arm c, at v, is another
arm W held in contact with the wheel X' by the spring Q. d, is a spring pawl,
which serves as a conductor, from wire E, to wheels X and X', which are
electrically connected by the pawis w and c. 9, is an electro-magnet by whose
action, through the armature j, rocking shaft E4, arm A, and rod, the pawl w, and
stop c, are operated. On operation a current is sent through the electro-magnet g,
thereby attracting its armature j, and through the action of the rocking shaft E
and arm and rod f. pulls the pawl w and arm c, forward.. As w, moves forward,
its turns wheels X' towards the right, but only as far as is determined by the
arm c, for when the wheel X' has been turned to the required distance, the arm c
has engaged with the wheel X, thereby locking both the wheels, which are rigidly
connected together and insulated from the shaft. Wheels X and X', are duplicates,
but are mounted on the shaft in such a manner that the teeth occupy reversed
directions. The wheels, by this method, are prevented from turning farther than
they should at one movement.
In Figure 6, which shows a different arrangement of an eight subscriber exchange,
the bars A, are all located on one side of the centre, and the ratchet wheel X has
twice the number of teeth, or sixteen, and has two arms, M, and M' and makes but
one half of a revolution at one operation. It is obvious that this construction can
be modified still more by having three or more arms, and causing it to make one-third
or less of a revolution at each operation.
In the operation of this exchange, suppose in Figure 2, that arm M¹ instead of
standing on connecting bar A' stands on its own, or A2; now, if the sub-station L,
wishes to call or put himself in communication with another sub-station for instance,
the sub-station M, he finds from a card with a list of subscribers thercon, the proper
number to call, which in this case is 7, as M's switch is seven in advance of his own.
The subscriber then puts plug 13, Figure 1, in the hole 6, and turns the shaft A,
to the right as far as it will go. On releasing it, the mechanism travels back, as
before described, and after sending seven impulses, stops, by reason of the arm H,
striking the plug 13, in hole 6. Referring again to Figure 2, it will be seen that
the transmitter H which is the one operated, has made and broken the circuit,
beginning with the ground F through the battery J', transmitter H¹, line K'
magnet G, and ground L, seven times. This has caused magnet G¹ to attract and
release its armature the same number of times and caused the ratchet or catch C¹ to
move the ratchet wheel X and arm attached, seven bars in advance, or in other
words, to rest, as shown on bar A¹.
It will be seen that now station L, is in direct communication with the station M.
The telephone circuit can be traced beginning with ground F¹ through the

page_text: magneto calling apparatus, line E', spring D', ratchet wheel X', arm M', contact
end Q, connecting bar A', contact end Q, arm M, ratchet wheel X2, spring D²,
line E, magneto calling apparatus terminating at ground F. The subscriber L,
calls M, by a magneto or other suitable means, and maintains connection with him
as long as desired. Referring to Figure 1, it will be noticed that the wheel B,
has been during this time in contact with insulated notched end of arm N. On
wishing to terminate the above described connection the subscriber L, moves the
plug 13, from the hole, 6, releasing the mechanism and allowing it to finish its
movement. In so doing it sends one inore impulse over the line K' and causes
the magnet G to turn the wheel X' and arm M' one more notch, bringing the
contact end Q', in contact with the starting point or bar A².
It is evident that suitable switches may be located at the various substations so
that a metallic return, a ground return, or both, may be used for telephoning
purposes only. By metallic return, in this case I mean the use of the calling line,
as shown at K', Fig. 2. And it is evident that the calling line and ground may
both be used at the same time for the return telephone circuit. No signal or call
that would disturb the electro magnets G, should be sent.
It will be noticed that I locate batteries for connecting purposes at subscriber's
end, instead of at the central station; this is because the niechanism would be
more apt to be disturbed by lines becoming accidentally grounded, or otherwise
disturbed, if batteries were located at the central station.
In Figure 3, O and L, are two sub-stations connected on the same line. As
they are normally in an open circuit to call each other, they must have their
switch M' at the central station grounded. This is accomplished by having one
bar, as shown at A, permanently grounded. Station L, is known to station O,
as 1, for one impulse is needed to place their switch on the grounded bar. Also
station O, is known as 1, to station I, for the same reason, but in calling each
other, one must be designated by a particular individual signal. Otherwise,
these stations are operated in the same manner as the others. Two or more
stations may be connected on any line or lines, but in these cases, individual
signals, such as two rings, three rings etc., each differing from the other must be
used by each subscriber on the telephone lines.
Figure 3, shows station M, connected to line E' and E2 so that by using an
individual signal, either station O, or station L, may be called.
As will have been seen from the preceding description, each subscriber will have
a list of all the other subscribers, with a proper calling number attached to each
name. As shown in Figure 4, each arm attached to the ratchet wheel is
connected through the ratchet wheel to a spring; thus, the first arm is connected
to the spring D, the second to the spring D2, and so on. As each subscriber is
connected to one of these springs, for convenience I will call D' and all the
other D's "subscribers," and omitting the D will simply designate them by
numbers. At 1, is located a card, containing the other seven subscribers' names.
To call 2 from 1, would require one impulse, for that is the number needed to
place 1's arms on A2 with 2's arm. To call 3, two would be needed, for 4, five"
and so on.
But at 2's station the operation would be different, for 2, to call 3,
would only require one impulse instead of two, as in the case of 1.
For 2 to
call 4 would need two instead of three at 1, and so on, at every station of the
series it would require one less impulse than at the preceding station, that is,
taking them as numbered in Fig. 4, 1, 2, 3, &c.
Therefore for calling purposes,
each subscriber bears a different number on each card located at the different
stations, for example, 3 is known as 3 to 8, as 2 to 1, as 1 to 2, and as 7 to 4 and
so on.
In Fig. 7, 11 is the relay operated by impulses from the sub-station over the
line K, to the ground L. 12 are the contacts operated by relay magnet 11,
controlling the circuit through the local battery 10, operating the magnet G over
live 9. This is the preferable mode of using the exchange.

page_text: Fig. 8 shows an arrangement whereby, in a large exchange, eighty for example,
ten bars or contacts may be moved at one time, thereby reducing the time
occupied in operating. 18 and 19 are the coils of a polarized relay through which
the line K, is directly connected to ground L. 20, and 21, are its local contacts.
15, and 16, are the local operating magnets, and 17, the local battery. By sending
impulses of one polarity 15 will operate the large wheel X one tooth at a time.
By sending impulses of the opposite polarity, 16 will operate and draw wheel X
ten teeth at one time. In calling 79, 16 would be caused to act seven times,
then 15 nine times, or 15 nine times, then 16 seven times. The transmitter at the
subscriber's end being so arranged as to always send seven impulses in the
direction to operate 15, and ten in the direction to operate 16, thus bringing
the switch at the central station, back to the starting point after each operation.
The transmitters may be two, like Fig. 1 one arranged to send seven impulses,
the other ten of opposite polarities, and simple means can be used to operate
one after the other, the batteries being suitably arranged.
Some of the changes obtained by my invention over the state of the art, are as
follows:
1. Each line is connected to a travelling switch, and permanently to nothing
else, all the switches being hung on, and insulated from a common shaft, and
capable of being rotated in one direction only independently.
2. Each switch, at every complete operation at its connecting sub-station, travels
over, in one direction, the entire series of bars. By so doing, all the contacts are
always kept bright and clean.
3. These bars are connected to any line or circuit only as a switch rests on one.
4. When normally at rest, the switches stand on and in contact with different
bars, preferably one in advance of the preceding one, or in other words, in a
spiral row.
5. By so standing in contact, each bar serves the purposes of a terminal for that
line whose switch is in contact with it.
6. By moving (preferably by ratchet wheel attached to switch and operated by
independent line from sub-station) a switch from its own bar, to contact with
another bar, two switches come in contact with this latter bar, and are, therefore,
connected in the most simple manner.
7. At the completion of the operation at the sub-station (which may be
interrupted for any length of time) the switch continues in the same direction and
goes over all the bars and stops in contact with the original or starting bar, in
readiness to call or be called again.
8. In this system in necessary cases, two or more subscribers, or sub-stations
may be connected on the same lines, a very important object sometimes, and
although on a normally open circuit (open at the central station) are enabled to
call and communicate with each other on the same line and be connected with no
other linę.
9. In case of accidental disturbance by reason of a partial ground contact with
electrically charged wires, or any other cause in which the normal resting point of
any switch is disturbed or changed to a wrong bar, the switch at the central
station can be righted or reset to its proper position by simple means at the
sub-station.
Referring to Figure 4ª, representing cards used in a five station exchange.
XY in order to call JS sends one impulse to call A B, two impulses: to
call RM, three impulses: to call A L, four impulses: JS, to call XY must
send four impulses: to call A B, one impulse to call R M, two impulses: to
call A L, three impulses. A B, to call J S, must send four impulses: to call XY,
three impulses to call R M, one impulse to call X Y three impulses: to call R M,
one impulse to call A L, two impulses, &c. &c.
:
:
:
I desire it to be understood that my invention is not limited to particular
details of construction and combinations of parts as herein set forth; but that

page_text: modifications may be made therein without departing from the nature of the
invention.
Dated this 29th day of March 1895.
R. J. URQUHART,
57, Barton Arcade, Manchester, and 5, Clayton Square, Liverpool,
Consulting Engineer and Patent Agent.
Improvements in Automatic Exchange Systems and Apparatus for
Telephonic and other Electrical Communication.
1, RIDLEY JAMES URQUHART of 57 Barton Arcade, Manchester in the
County of Lancaster, Consulting Engineer and Patent Agent, 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 automatic exchange systems and apparatus for telephonic-
and other electrical communication.
Its object is to do away with the use of employees and managers at the central
station, and, therefore, to reduce the operating expenses. The special object of
the invention is to simplify and otherwise improve the present systems having a
similar object.
66
By telephone lines" in the following description I mean those lines which are
to be connected by the automatic central exchange device. They may be used
also to connect circuits in telegraph systems; or in systems of seeing by electricity.
It is applicable to any system in which apparatus at one sub-station is to be placed
in electrical communication with apparatus at another sub-station, through a device.
located at an intermediate station.
I find it convenient to use the words "calling lines" to indicate those lines.
which are used for operating the switchboard. Sometimes I employ for the central
station switch board merely the words "the central station" and the outlying
stations I call either "subscribers or "sub-stations."
""
All the details of the invention are represented on the drawings sent in with the
Provisional Specifications which are hereinafter referred to. Generally speaking,
the figures show the invention mostly in diagram, so as to bring out more clearly
the individual elements which comprise the invention as a whole.
Figure 1, is an elevation of the apparatus employed at the sub-stations for
operating the central station device, which may be called the switchboard, while
the device shown in Figure 1, may be called a switchboard transmitter.
Figure 2, is intended to represent the electric circuits from one sub-station to
another sub-station through the central station board, which is represented as to its
necessary elements in perspective.
The transmitter in Figure 1, is represented twice in Figure 2, but only as to
mere outline of one or two of its elements. The switchboard shewn is adapted to.
put eight subscribers into electrical communication.
Figure 3, is a similar view to that shown in Figure 2, for illustrating how
two subscribers on one line may be connected to one subscriber on another line.
In Figure 2, only a portion of the switchboard is shown; but in Figure 4, is a
perspective view of all the connecting bars, ratchet wheels, and switches, as they
stand at rest on an eight subscriber exchange.
Figure 4A, shows the system of cards at the sub-stations.
Figure 5, shows a modification of means for operating the ratchet wheels. It is
a perspective view.
Figure 6, is a modification of an eight subscriber switchboard in end view. The

page_text: ratchet wheel has twice the number of teeth, and has two contact arms. All the
contact bars can therefore, be arranged on one side of a circle.
Figure 7, illustrates the application of a relay for the operation of the switch-
board, so that the current passing over the main line between the several stations
need not be very much, because the local current which is operated by the relay
may be caused to do all the work.
Figure 8, shows a modification of the arrangement shown in Figure 7, whereby
a pularised relay is employed, and whereby the number of sub-stations may be
multiplied without materially increasing the intricacy of the central station switch-
board.
I will first describe the invention by particular reference to Figure 1.
A, is a shaft capable of rotation in either direction and rigidly mounted thereon
is the segmental wheel, B, with eight raised surfaces C1, C2, C3, C4, C5, C6, C7,
and C, and on one side the depression D, is considerably more in depth than the
notches X, on the opposite side. E, is an arm held in position on the wheel B, by
the screw F, and is adjustable sideways by the screw F, and slot G. H, is an arm
pivoted at J, and held against the stop K, by the spring L, so that the outer end M,
is movable only to the left, as viewed from the centre or shaft A. N, is an arm of
insulating material, while O, is a strip of conducting substance mortised into the
side. The arm, N, is pivoted at P, and is held normally in position as shown,
pointing toward shaft A, by the flexible strip or spring R, working between the
two pins S, and S. T, is a cord or chain, one end fastened around the drum U,
which is fastened rigidly on the shaft A, and the other end fastened to the spring V,
which is fastened to the frame work at W. The tendency of the spring being to
always bring the arm H, against the stop Y. Z, is a binding post connected to
the conducting strip O, and Z, another binding post connected through the frame
work to the teeth C, C, etc. The point 5 is siniply a normally open contact point,
whose use will be explained later. 6, 7, 8, 9, 10, 11, and 12, are holes the proper
size to hold the plug 13. The shaft A, carries the gear wheel a; engaging with
the pinion a', having a fan wheel a¹¹, all so arranged in such a manner as to cause
the shaft A, when revolved by the action of the spring V, and chain T, to move at
a comparatively slow rate of speed. Also, rigidly attached to shaft A, but not
shown, is a crank, by the action of which shaft A, is turned by hand in a direction
contrary to the pull of the chain and spring. When normally at rest, arm H, rests
against the stop Y, and arm N. points directly toward shaft A, as represented in
the drawing. On revolving shaft A, together with its wheel and arm attached, in
a direction to the right, as seen in looking at the drawing, arm N, is forced back-
ward, and when arm H, passes the hole 6, arm N drops into the first notch X, and
by its end resting against Cs, prevents wheel B, from turning backward. This
action continues on all the notches until the last one C³, has passed, when the
arm N, drops into the depression D, and once more points directly toward the
shaft A. While said arm N, has been making engagement with the wheel teeth,
it has been touching said teeth only by its insulated side. The wheel B, in its first
movement is carried around so far that the arm N, can entirely escape from the
teeth and rim to its radial position in reference to the centre A, in order to be
ready for the reverse movement of the wheel B, which will throw the arm N in
the position shown dotted. Of course the wheel B, need not be turned around in
its first or forward movement any further than simply to let the arm N drop into
its radial position after the teeth have all passed it. Now if shaft A, is
released, it starts to travel back slowly by action of spring V and retarding
wheels, and thereby arm N, is thrown in the opposite direction, as shown by the
dotted lines in the drawing. The teeth on wheel B, one after the other, strike
first upon the conducting strip O, and then upon the insulating body of arm N,
causing, by these alternate makes and breaks, successive impulses to travel over
the lines attached to the binding posts Z, and Z. Always supposing a battery or
other source of electricity in circuit with said lines. Supposing, that before
operating the transmitter, plug 13, to have been placed in some one of the holes, for

page_text: example, in hole 1. In turning by hand in the direction towards the right, arm H,
would spring past the plug 13 in hole 10, but on returning, going in the opposite
direction, arm H, would not spring by, but would cause the entire stoppage of
all the moving parts. Three impulses would have gone over the circuit. This
circuit is attached to an operating magnet at the central station, and these impulses
cause a switch at said central station, connected by another wire, to a telephone
or other communicating instrument, located at the same sub station as the trans-
mitter, to have moved three contacts in advance, as will be explained hereafter,
and come in contact with a contact bar occupied by a switch from another
sub-station, thus putting the two sub-stations in electrical connection with each
other, and this connection will be maintained until plug 13, is removed from
hole 1. By the stoppage of the moving parts by the plug 13, in the hole 10,
communication may be carried on telephonically with a distant station until the
two parties have finished their conversation. Then the plug 13, may be removed
from the hole 10. When that occurs, wheel B, continues its rotation, making five
more contacts with the conducting plate O, and by so doing making its switch
at the central station complete an entire revolution and come to rest at the
starting point. The whole system is now ready for use for the purpose of com-
municating again with the same or a different station, and the operation if repeated
would be substantially the same as above described, except that the plug. 13,
would be put into the proper hole according to instructions conveyed by the
cards shown in Figure 4 A hereinafter described. Further, in order to understand
the above mere ontline of communicating with a distant substation, the reader
is referred to matter stated hereinafter, where the remaining elements of the
central station named in the operation are indicated by reference letters.
the last direction that wheel B moved, the arm N, also makes engagement with
the teeth C, and prevents backward motion, so that in operating, nothing but the
complete number of impulses can be seut, as arm E, must be moved past all the
holes before it can return, and when started back must come to the starting
point before another call can be made.
ln
If, frem accident, the subscriber's switch at the central station should come to
rest on the wrong bar, for instance, five in advance of his own, he, ascertaining by
calling the said fifth subscriber, the number he is on and finding it five, and knowing
that three more complete the cycle of eight, sends three impulses over the calling
line by the key 5, and brings his switch at the central station to the proper position.
It is evident that any subscriber on any size of exchange, can re-set his switch, if
disturbed, in the same manner.
The insulated pawl N, has a notch N' at the end for the purpose of causing the
tooth as soon as it has passed off the conducting strip O to slip off the upper
surface, so that it cannot be moved backwards and by making contact again send.
a wrong impulse, while the recessed part of the insulated pawl prevents it from
striking against the next tooth. Also the plug holes are so placed that the arm H,
on striking the plug 13, will bring a tooth on the wheel B, in such a position that
the notch N', in the end of the pawl N, will prevent backward movement and will
also prevent the conducting strip O, from making contact with the next tooth.
This also prevents the battery from being maintained in circuit during the
operation of the telephone or other instrument.
In Figure 2, representing two subscribers' connections on an eight subscriber,
exchange, A1, A2, A3, A4, A5, A6, and A8, are stationary contact rods or bars.
X', and X2 are ratchet wheels with eight teeth apiece, into which the pawls C',
and C, play. The wheels' backward motion is prevented by the springs D1 and D²,
engaging with said teeth. The springs D1 and D2, serve as conductors from the,
wheels X, and X2 to the telephone lines E' and E, attached to the sub-stations L,
and M respectively. M' and M2, are arms with spring contact ends Q1 and Q²,
and they are rigidly attached to, and in electrical connection with X and X,
which revolve on, but are insulated from the shaft N. Each ratchet wheel and
arm is insulated from the other ratchet wheels and arms. The other end of the
B

page_text: ircuits E¹, and E2 are grounded at F, and F2 respectively. G and G2 are
electro magnets controlled by transmitters H' and H2, and batteries J¹, and J2,
over the lines K and K2, respectively. G¹ and G2 are also connected to the
common ground L. Batteries Jaud Jare connected to ground at F1 and F2,
respectively. Contact ends Q' and Q2 are adapted to make contact, one after the
other, with each stationary contact bar in the A series. When normally at rest, the
contact rod Q'lies in contact with contact rod A2, while contact rod Q² is in
contact with the contact rod A'. As shown in the drawings, the sub-station I
has connected itself to the sub-station M, by moving his contact bar M', seven
bars in advance, or to A', as explained hereafter. Consequently, both arms are in
contact with rod A'.
Figure 3, shows the same general connections, and is designated by the same
letters as in Figure 2, with the exception that one of the stationary bars A³, is
permanently connected to the common ground 1, and two sub-stations O, and L,
are shown connected on the same line.
+
Figure 4, as before explained, shows in perspective all the contact arms of
an eight subscriber exchange at rest in a spiral row, each in contact with a
separate bar.
In Figure 5, c represents an arm pivoted or journalled at
and held when at
rest, against the stop s, by the spring t. Pivoted on the arm c, at v, is another
arm w held in contact with the wheel X, by the spring Q. d, is a spring pawl,
which serves as a conductor from wire E, to wheels. X and X', which are
electrically connected by the pawls w and c. g, is an electro magnet by whose
action, through the armature j, rocking shaft E', arm h, and rod f, the pawl w,
and stop c, are operated. On operation a current is sent through the electro-
magneto, thereby attracting its armature j, and, through the action of the rocking
shaft E and arın h and rod f, pulls the pawl w, and arm e, forward. As w, moves
forward, it turns wheels X, towards the right, but only as far as is determined
by the arm c, for when the wheel X', has been turned to the required distance, the
arme has engaged with the wheel X, thereby locking both the wheels, which are
rigidly connected together and insulated from the shaft. Wheels X and X', are
duplicates but are mounted on the shaft in such a manner that the teeth occupy
reversed directions. The wheels, by this method, are prevented from turning
farther than they should at one movement.
In Figure 6, which shows a different arrangement of an eight subscriber
exchange, the bars A, are all located on one side of the centre, and the ratchet X
has twice the number of teeth, or sixteen, and has two arms M, and M', and makes but
one-half of a revolution at one operation.. It is obvious that this construction cau
be modified still more by having three or more arms, and causing it to make one
third or less of a revolution at each operation.
U
In the operation of this exchange, suppose, in Figure 2, that arm M', instead
of standing on connecting bar A¹, stands on its own, or A2; now, if the sub-
station L, wishes to call or put himself in communication with another sub-station,
for instance, the sub-station M, be fiuds from a card with a list of subscribers
thereon, the proper number to call, which in this case is 7, as M's switch is seven
in advance of his own. The subscriber then puts plug 13, Figure 1 in the hole 6,
and turns the shaft A, to the right as far as it will go. On releasing it, the
mechanism travels back as before described, and after sending seven impulses,
stops, by reason of the arm H, striking the plug 13, in hole 6. Referring again
to Figure 2, it will be seen that the transmitter H which is the one operated, has
made and broken the circuit, beginning with the ground F¹, through the battery J,
transmitter H¹, line K', magnet G and ground I, seven times. This has caused
inagnet G to attract and release its armature the same number of times and caused
the ratchet or catch C¹ to move the ratchet wheel X', and arm attached, seven
bars in advance, or in other words, to rest, as shown on bar A¹.
It will be seen that now station L, is in direct communication with the station M.
The telephone circuit can be traced beginning with ground F', through the

page_text: magneto calling apparatus, line E', spring D', ratchet wheel X₁, arm M', contact
end Q, connecting bar A', contact end Q, arm M², ratchet wheel X2, spring D³,
line E, magneto calling apparatus terminating at ground F. The subscriber L,
calls M, by a magneto or other suitable means, and maintains connection with him
as long as desired. Referring to Figure 1, it will be notice.l that the wheel B, has
been during this time, in contact with the insulated notched end of arm N. On
wishing to terminate the above described connection, the subscriber L, removes the
plug 13, from the hole 6, releasing the mechanism and allowing it to finish its
movement. In so doing it sends one more impulse over the line K' and causes the
magnet G to turn the wheel X' and arm M¹ one more notch, bringing the contact
end Q', in contact with the starting point or bar A³.
It is evident that suitable switches may be located at the various substations so
that a metallic return, a ground return, or both, may be used for telephoning
purposes only, By metallic return, in this case, I mean the use of the calling line,
as shown at K', Fig. 2. And it is evident that the calling line and ground may
both be used at the same time for the return telephone circuit. No signal or call
that would disturb the electro magnets G, should be sent.
It will be noticed that I locate batteries for connecting purposes at subscriber's
end, instead of at the central station; this is because the mechanism would be more
apt to be disturbed by lines becoming accidentally grounded, or otherwise disturbed,
if batteries were located at the central station.
In Figure 3, O and L, are two sub-stations connected on the same line.
As they
are normally in an open circuit to call each other, they must have their switch M³,
at the central station grounded. This is accomplished by having one bar, as shown
at A, permanently grounded. Station L, is known to station O, as No. 1, for one
impulse is needed to place their switch on the grounded bar. Also station O is
known as No. 1, to station L, for the same reason, but in calling each other, one
must be designated by a particular, individual signal. Otherwise, these stations are
operated in the same manner as the others. Two or more stations may be connected
on any line or lines, but in these cases, individual signals, such as two rings, three
rings etc., each differing from the other, must be used by each subscriber on the
telephone lines.
Figure 3, shows station M, connected to line E' and E2, so that by using an
individual signal, either station O or station L, may be called.
As will have been seen from the preceding description each subscriber will have
a list of all the other subscribers, with a proper calling number attached to each
name. As shown in Figure 4, each arm attached to the ratchet wheel is connected
through the ratchet wheel to a spring; thus, the first arm is connected to the
spring D, the second to the spring D, and so on. As each subscriber is connected
to one of these springs, for convenience I will call D' and all the other D's.
"subscribers," and omitting the D, will simply designate them by numbers. At 1
is located a card, containing the other seven subscribers' names. To call 2 from 1,.
would require one impulse, for that is the number needed to place 1's arm on A²
with 2's arm.
But.
at 2's station the operation would be different, for 2, to call 3, would only require
one impulse instead of two, as in the case of 1. For 2 to call 4 would need two
instead of three at 1, and so on, at every station of the series it would require one.
less impulse than at the preceding station, that is, taking them as numbered
in Fig. 4, 1, 2, 3, &c. Therefore for calling purposes, each subscriber bears a
different number on each card located at the different stations, for example, 3 is
known as 3 to 8, as 2 to 1, as 1 to 2, and as 7 to 4, and so on.
To call 3, two would be needed, for 4, five and so on.
In Figure 7, 11 is the relay operated by impulses from the sub-station over the
line K, to the ground L. 12 are the contacts operated by relay magnet 11,
controlling the circuit through the local battery 10, operating the magnet G, over
line 9. This is the preferable mode of using the exchange.
Fig. 8 shows an arrangement whereby, in a large exchange, eighty for example,
ten bars or contacts may be moved over at one time, thereby reducing the time

page_text: occupied in operating. 18 and 19 are the coils of a polarized relay through which
the line K, is directly connected to the ground L. 20, and 21 are its local contacts,
15, and 16, are the local operating magnets, and 17, the local battery. By sending
impulses of one polarity, 15 will operate the large wheel X, one tooth at a time.
By sending impulses of the opposite polarity 16 will operate and draw wheel X ten
teeth at one time. In calling 79, 16 would be caused to act seven times, then 15 nine
times, or 15 nine times then 16 seven times. The transmitter at the subscriber's
end being so arranged as to always send seven impulses in the direction to
operate 15, and ten in the direction to operate 16, thus bringing the switch at the
central station, back to the starting point after each operation. The transmitters
may be two, like Fig. 1, one arranged to send seven impulses, the other ten, of
opposite polarities, and simple means can be used to operate one after the other, the
batteries being suitably arranged.
Some of the changes obtained by my invention over the state of the art, are as
follows:-
1. Each line is connected to a travelling switch, and permanently to nothing else,
all the switches being hung on, and insulated from a common shaft, and capable of
being rotated in one direction only independently.
2. Each switch, at every complete operation at its connecting sub-station, travels
over in one direction the entire series of bars. By so doing, all the contacts are
always kept bright and clean.
3. These bars are connected to any line or circuit only as a switch rests on one.
4. When normally at rest, the switches stand on and in contact with different
bars, preferably one in advance of the preceding one, or in other words, in a
spiral row.
5. By so standing in contact, each bar serves the purpose of a terminal for that
line whose switch is in contact with it.
6. By moving (preferably by ratchet wheel attached to switch and operated by
independent line from sub-station) a switch from its own bar, to contact with
another bar, two switches come in contact with this latter bar, and are, therefore
connected in the most simple manner.
7. At the completion of the operation at the sub-station (which may be interrupted
for any length of time) the switch continues in the same direction and goes over all
the bars and stops in contact with the original or starting bar, in readiness to call
or be called again.
8. In this system in necessary cases, two or more subscribers, or sub-stations may
be connected on the same line, a very important object sometimes, and although on
a normally open circuit (open at the central station) are enabled to call and
communicate with each other on the same line and be connected with no other line.
9. In case of accidental disturbance by reason of a partial ground contact with
electrically charged wires, or any other cause in which the normal resting point of
any switch is disturbed or changed to a wrong bar, the switch at the central station
can be righted or re-set to its proper position by simple means at the sub-station.
Referring to Figure 44, representing cards used in the five station exchange.
XY in order to call J S, sends one impulse, to call A B two impulses: to call R M,
three impulses to call A L, four impulses: J S, to call X Y, must send four
impulses to call A B, one impulse to call R M, two impulses: to call A L,
three impulses. A B, to call J S must send four impulses: to call X Y three
impulses to call R M, one impulse to call A L two impulses, &c. &c.
:
desire it to be understood that my invention is not limited to particular details
of construction and combinations of parts as herein set forth; but that modifications
may be made therein without departing from the nature of the invention.
Having now particularly described and ascertained the nature of my said inveu-
tion and in what manner the same is to be performed, I declare that what I
claim is :-
1. In an automatic telephone exchange system, the combination of a backward

page_text: and forward moving intermittent circuit closer for producing intermissions of
currents during its backward movement only, neaus for stopping the circuit closer
at any one of several predetermined positions during its backward movement, and
a stop located at the normal position of the circuit closer for stopping said circuit
closer at the end of its backward movement.
2. In an automatic telephone exchange system, a transmitter for operating the
central station transfer instrument, consisting of the combination of a central axle,
a notched disc forming an electric terminal, and rotary about the axle, a yielding
electric terminal lying in the path of the projections formed by the notches, means
for retracting the notched disc, and a plug for stopping the disc at any one of a.
given number of positions, said yielding terminal being insulated from the disc
terminal during its former motion.
3. In an automatic telephone exchange system a transmitter for operating a
central station transfer instrument, consisting of the combination of a backward
and forward moving intermittent circuit closer, for producing intermissions of
currents during its backward movement only and means for stopping the circuit
closer at any one of several predetermined positions during its backwar
movement.
4. A system of electrical intercommunication consisting of a set of electrical
conductors extending from sub-stations to a central station in which each conductor
terminates in a switch only, a series of stationary "dead" bars A', A2, A3, etc.,
arranged in the paths of the switches or terminals; a second set of electrical
conductors from the sub-stations and connected at the central station through
magnets to a return circuit and mechanisms at the respective sub-stations and
central station whereby two or more terminals of the first set of conductors, may
by means of the magnets in circuit with the second set, be automatically placed in
electrical connection with each other through one of the dead bars.
5. An automatic switch-board for a central station in a system of electrical
intercommunication consisting of the combination of stationary conducting bars,
terminals connected with the telephone lines for making contact therewith, and
independently movable from the sub-stations, and means for automatically bringing
two or more of the movable terminals into electric contact with one of the
stationary bars.
6. In an automatic telephone exchange a group of stationary dead bars A', A2, A³,
etc, and means for bringing two or more circuits into electrical connection with one
bar at the same time.
7. In a system of electrical intercommunication a group of stationary dead bars,
terminals of telephone lines detachably connected therewith, the said bars being in
a circular row in the paths of all the terminals.
8. An automatic telephone exchange switch-board, consisting of the combination
of parallel conducting rods and radial arms, ratchet wheels carrying each one of
the radial arms which are of such a length as to come in contact with the
conducting rods, and the ratchet wheels being independently rotary upon an
insulated rod, and electro mechanical devices for operating the respective ratchet
wheels for the purpose of bringing two or more of the radial arms in connection
with one rod.
9. An automatic telephone exchange switch-board, consisting of the combination
of stationary parallel conducting rods and radial arms, ratchet wheels carrying
each one of the radial arms which are of such length as to come in contact with
the rods, and the ratchet wheels being independently rotary upon and insulated
from a rod, and electro mechanical devices for operating the respective ratchet
wheels to bring one or more of the radial arms in contact with one rod, the said
ratchet wheels being rotary in one direction only.
10. In a system of electrical intercommunication, a group of switches or contacts,
each switch or contact being capable of rotation in oue direction only, and when
normally at rest in contact with a connecting rod or bar, by such contact making
said rod or bar the terminal of the line or circuit attached to said switch or contact,

page_text: said rods or bars being arranged in a circular row in the paths of all the switches
or contacts.
11. In a system of electrical intercommunication, conducting bars arranged in a
circular row, a system of switches located, when normally at rest, in a spiral row
and insulated from one another in such a manner that each switch is in electrical
contact with its own independert stationary switch bar, thereby making such bar
the terminal of the line or circuit attached to said switch or contact.
12. In a system of electrical intercommunication, a system of cards or signs,
numbering one for each station, and each one located at its own station; each one
consisting of duplicate lists of all the stations, but each station bearing a different
calling number on each sign or card, said number always corresponding to the
number of impulses necessary to put the particular station at which said number on
said sign or card is located in electrical connection with the said number or station,
substantially as described.
13. In a system of electrical intercommunication employing circuits normally
open at the central station, of a contact A' permanently connected to ground or
other return circuit, and situated in the path of a movable terminal of a line which
includes telephone in series with each other for furnishing a circuit for the said
line, which is attached to said terminal when on said contact, independently of
connecting said line with any other of the said terminals.
14. An automatic telephone exchange system, consisting of the combination of
parallel stationary conducting rods insulated from one another and arranged
circularly, rotary electric terminals connected in circuit with telephones at different
sub-stations and adapted to come in contact with any one of the said rods, and
electro mechanical means Incated in circuit with intermittent circuit closers at the
sub-stations for bringing two or more rotary terminals in contact with the same rod
to complete the electric circuit between the sub-stations.
Dated this 31st day of December 1895.
R. J. URQUHART,
57, Barton Arcade, Manchester, and 5, Clayton Square, Liverpool,
Consulting Engineer and Patent Agent.