Electro-mechanical Switch and System of Electrical Inter- communication.
Year: 1893

page_text: Date of Application, 5th June, 1893-Accepted, 8th July,
1893
COMPLETE SPECIFICATION.
Electro-mechanical Switch and System of Electrical Inter-
communication.
1, EMERY ARTHUR CLARK, of 118 Bluff Street, Sioux City, in the County of
Woodbury and State of Iowa, one of the United States of America, Gentleman,
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 modes and machines for switching currents of electricity
from one telephone wire, telegraph wire, or other wire for the transmission of
electricity to another wire, or to any one of a system of wires converging to a
central point and enabling any person at any outlying station of any such
telephone, telegraph or other similar system of electrical intercommunication to
place himself in communication with any other outlying station in the system,
without the assistance of any central office, but solely by the use of my invention,
which consists of a dial near the circumference of which are numbered points
corresponding in number to the number of wires desired to be operated in the
system, the said dial being provided with a movable pointer or indicator which
passes step-by-step over the numbered points aforesaid, said indicator being attached
to and moved by a wheel placed behind the dial, which wheel is provided with cogs
equal in number to the numbered points above mentioned, which cogs, as the wheel
is rotated, make and break electric contacts and thus send electric pulsations
through an electro-magnet, situated at the central point of the system. This
electro-magnet is provided with an armature of peculiar and novel construction
which, when the electro-magnet is energized, is held from contact with it by a
spring, the tension of which is overcome by each of the pulsations above mentioned,
giving to the armature an oscillating or to-and-fro motion, whereby a wheel is set
in motion which carries a contact-spring over points of contact with every other
Each station is provided
wire in the system successively, at the will of the user.
with one of the above-mentioned switches. At central point all switches are
suitably interconnected and operated in a manner hereinafter described by a
common battery, also situated at central point and there grounded. The object of
my invention is to enable the user, by means of the automatic action of my inven-
tion, to put himself in communication with any other wire of a system by thus
actuating his switch at central point.
I attain this object by the mechanism illustrated in the accompanying drawings,
in which :-
Fig. 1 is a front view of the switch at central point, showing the wires, battery
and other mechanism intimately connected with it, which operate it.
Fig. 2 shows the dial at user's station, partly broken away to display mechanism
underneath.
Fig. 3 shows a modification of the arrangement of numbered contact-points in
Fig. 1 to adapt them to three different uses.
Fig. 4 shows underside of switch-wheel with additions necessary in using the
invention in systems having metallic circuits.
Fig. 5 shows side view of mechanism shown in Fig. 4.
Fig. 6 shows instruments at central point, their connections and three outlying
stations in diagram.
Fig. 7 shows modification of armature lever for special purposes.
In the following Specification in referring to lines and instruments used for the
actual work of electrical intercommunication, as telegraph and telephone lines and
instruments, I call them "service" instruments, etc.; using the term "switching'
"

page_text: lines, etc. to designate those parts of the system used for making connections
between "service" lines.
The mechanism used directly by the operator is shown in Fig. 2, and is set in
operation by the hand or other power applied to the rotation of the breaking-wheel P,
preferably by means of the series of cog-wheels T T and P (though obviously
breaking-wheel P is the only one essential to my invention) actuated by the
crank S, the purpose of this gearing being to give the wheel P and the indicator Q
a slower movement than they would otherwise have, thus decreasing the probability
of the operator's moving the mechanism past the desired point, and by this slower
movement rendering the working of the mechanism in Fig. 1 more regular,
accurate and reliable. W is a switching wire running from magnet E E at central
point to breaking-wheel P at outlying station and connected to the bearing of
wheel Pas shown in Fig. 2. X is a return or ground wire connected with ground-
spring R.
Whenever a contact is made between ground-spring R and wheel Pa
circuit is completed through electro-magnet E E, common battery Y, switching-
wire W, breaking-wheel P, ground-spring R and wire or ground X. Spring Ris
so adjusted as to touch only the tips of the cogs of wheel P as said wheel is
revolved, so that when wheel P is set in motion during each of its revolutions this
circuit is completed and broken as many times as there are cogs in its periphery.
Vis a spring-dog so shaped and adjusted as to press between the cogs of wheel P
and give it a step-by-step motion with pauses or halts when the point of dog V
presses between two cogs. The mechanism is so adjusted that each of these steps
forward carries indicator Q forward a distance equal to the space between two of
the points on the dial, and so that when the pauses or halts occur the indicator
pauses directly over one of the numbered points or one of the blanks or resting-
points pt, and so that at each pause or halt of wheel P spring R is disengaged from
wheel P (and circuit consequently broken) by reason of its point standing between
two cogs.
The dogs UUU are so adjusted as to prevent any backward movement of
the mechanism, thus preventing any contacts being made except by a forward.
movenient of the mechanism.
As wheel P revolves its cogs coming in contact with spring R make and break
electric contacts, sending electrical pulsations from battery Y through electro-
magnet E E.
Armature D, when the circuit is broken, is by the tension of the
springs disengaged from magnet E E, but when the circuit is completed it is
drawn by electro-magnetic attraction against the ends of the magnet E E, as shown
in Fig. 1, and on the circuit being broken spring sp draws it back again. Thus as
the mechanism shown in Fig. 2 is operated armature D constantly oscillates
to-and-fro, and in my invention this motion is communicated to switch-wheel A
giving it a rotary motion. I prefer to accomplish this by means of the peculiar
formation of that end of the armature D which is next wheel A (the other end
being hinged or fulcrumed as shown in Fig. 1), which peculiar formation consists
in furnishing armature D with a bifurcation or straddle, ending in two pawl-like
points dd, dd, situated on opposite sides of the periphery of wheel A. and so
shaped and adjusted that as armature D moves back and forth the points dd, dd, are
alternately driven between the teeth with which the periphery of wheel A is furnished.
These teeth are all made to slope in one direction, and points dd, dd, are so
shaped and adjusted that, in being so driven against the sloping sides of said teeth,
their pressures on the slopes of said teeth constantly urge wheel A forward and
cause it to revolve. This wheel A is propelled and controlled by armature D which
is actuated in part by the tension of spring sp, and in part by the attraction of
magnet E E.
It is obvious that this armature may have its hinge or fulcrum at
any part of its length, or on a projection furnished for it, and that both ends may
be forked or bifurcated for the purpose of propelling an additional wheel, and
these bifurcations may be increased to drive still other wheels, as desired, as shown
in Fig. 7.
Wheel A is placed in the centre of a circle of contact-points, insulated from

page_text: each other on the switch-board O', which are numbered to correspond with the
numbered points on the dial O, Fig. 2, in this case from 1 to 70 (but obviously any
desired number may be used) and this circle of contact-points is furnished with the
blanks or resting-points pt, in exactly the same manner as is the dial O afore-
said. Wheel A has attached to it and carries with it a metallic contact-spring B,
and is connected by service wire C with telephone, telegraph or other instrument
at outlying station, more or less remote, where dial O, Fig. 2, is situated. Each
outlying station of the telephone, telegraph or other system in which my invention
is used is furnished with a switch-board O', and these switch-boards are preferably
collected and suitably interconnected at some central point. Each service wire
in the system runs to the same central point and is there connected to its own
wheel A on its own switch-board O', and also by branches to its own numbered
contact-point on all other switch-boards. Thus station 1 is connected by its service
wire to its own switch-board at central point, and also to point 1 on all other
switch-boards. Station 2 is connected to its own switch-board, and to point 2 on
all other switch-boards and so on through the entire system as is clearly shown in
diagram Fig. 6.
The mechanism is so adjusted that when the electrical circuit is broken in the
revolution of wheel P, armature D is released from magnet E E and drawn back by
spring sp. By the action of the points dd, wheel A is propelled forward and
stopped with contact-spring directly over and resting and pressing upon one of the
numbered points on the switch-board O¹. A circuit is thus formed through service
wire C, wheel A, contact-spring B, and the service wire in the system corre-
sponding in number to the number of the contact-point on switch-board O' covered
by spring B.
To illustrate the mode of using and operating my invention I will suppose it
applied to a telephone exchange of say, for simplicity, three numbers, as shown in
Fig. 6. In this figure, for greater clearness, the different parts of the diagram
are indicated by words instead of letters. The outlying stations are marked
"Station 1," "Station 2" and "Station 3 ;" the switch-boards at central point
are marked "Switch-board No. 1," "Switch-board No. 2" and "Switch-board
No. 3." From the magnet of each switch-board as shown the wire marked
"Switching-wire" runs to dial at outlying station, and from each switch-wheel
runs the wire marked "Service-wire" to telephone at outlying station. From each
wire marked "Servire wire" branches are clearly shown running to a properly-
numbered contact-point on each other switch-board. Each subscriber is provided
with a dial O, and is connected with his own switch-board O' at a central point,
and the indicator stands at a point on dial O corresponding in number to the
number of the contact-point or blank covered by spring B on switch-board. The
operator (say No. 1) wishes to communicate with another member of the exchange
(say No. 2). To do this he turns crank S until the indicator Q reaches the
number 2. During this operation electric contacts have been made and broken
corresponding in number to the number of cogs of breaking-wheel P which have
passed ground-spring R, and also corresponding in number to the number of
numbered points on the dial O traversed by the indicator Q. By these electric
pulsations acting through the magnet E E aided by spring sp, the armature D has
propelled forward the switch-wheel A and brought the contact-spring B to a
contact-point on switch-board O₁ exactly corresponding to the numbered point
covered by the indicator Q on dial O, and the operator's telephone is placed in
communication with telephone No. 2 in the system through their respective service
wires, as shown in Fig. 6. And any telephone in the system may be placed in
communication with any other in the same manner. On discontinuing the connection
the operator moves his indicator Q forward to any resting-point pt on switch-
board O', and the instruments are disconnected for leaving out of use. In a manner
similar aud substantially as above described my invention may be applied to other
systems.
In Fig. 3 the switch-board is represented as divided into sections, each section

page_text: :
being put to a different use. Section shows method of using my invention the
same as above set forth, C representing the service wire.
In Section 2, Fig. 3, is shown the method of making and breaking contacts
when switch-board O' is used on circuits grounded by working in through an
annunciator or bell. The numbered points on switch-board O from 51 to 60
inclusive are in this case flat springs. I represents service wire from numbered
spring to operating-point where dial is located. The numbered springs rest on
numbered contact-points indicated in Fig. 3 by dotted lines on numbered springs.
These under-contact-points are connected to ground through annunciator or
bell by wire J in the usual manner. When the mechanism is operated as above
set forth spring B slides under the numbered springs, and being stopped at any one
of them makes a contact with it and at the same time raises the numbered spring and
breaks contact of numbered spring with under-contact-point. When spring B is
moved the numbered spring returns to its place on contact-point restoring original
circuit to exchange or system.
To use my invention on systems having metallic circuits I modify wheel A and
spring B as shown in Fig. 4. F is a metallic collar or commutator insulated from
wheel A by the interposition of insulation Z. G is a metallic spur or conductor,
preferably covered with insulating material, except at the end, which is left_bare
for a contact-point, but is insulated from spring B as shown at n, Fig. 5.
LL are
wires of metallic circuit, one end connected with wheel A, the other connected
with commutator f, through commutator-spring m, which bears on commutatory.
KK are wires which when brought in connection with L L by the mechanism are
thrown into a circuit with L L. In Figs. 3, 4 and 5, K K are shown connected
with numbered contact-spring and under-contact-point 61 and 61. When the
mechanism is moved as aforesaid and spring B is stopped under any numbered
contact-spring (61 in this case) a complete metallic circuit is formed through the
wires L L and K K and the commutator-spring in the insulated collar f; the
insulated conductor g, the insulation Z and n keeping the two sides of the circuit
from contact with each other.
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. In a system of electrical intercommunication, a system of service lines
converging from outlying stations to a central point, and having at said central
point each service-wire connected by a branch thereof to its own switch-wheel, and
by other branches thereof to a terminal point, as shown on every other switch-
board in the system, in combination with an accompanying system of switching
lines, consisting of one switching wire from each of the said outlying stations
converging to the same central point and there grounded through a common central
battery, said switching system being electrically unconnected with and independent
of said service system; all in combination with connecting mechanism so arranged
and disposed at the point of convergence of said switching lines, and at the outlying
terminals thereof, as to be capable of being so manipulated from outlying stations
that any one of said service lines may at will, by said mechanism, actuated by said
switching system, be automatically placed in said electric circuit with any other
service line in the system, substantially as set forth.
2. In a system of electrical intercommunication, a system of service lines or
wires converging to a central point, a system of switching lines or wires consisting
of a single wire, converging as shown, from each of the same outlying stations to
the same central point, said system of switching wires being electrically unconnected
with said system of service wires; a common central battery at central point,
through which said switching wires are grounded; all in combination with
connecting mechanism consisting at each outlying station of the system of a dial,
provided with an indicator moving over its surface in obedience to the rotation of a
metallic breaking-wheel, which is electrically charged through its switching wire

page_text: by said common battery at central point, and so formed that portions of its surface-
in its rotations make and break contacts, with a suitable ground connection provided
therefor, thus sending a determinate number of electrical impulses through switching
wire and an electro-magnet connected therewith at central point, which when thus
energized, by means of the bifurcation with pawl-shaped points of a spring-
controlled arinature, actuates one of a system of suitably interconnected switch-
boards at central point; said number of electrical impulses being indicated by the
number of properly-designated points passed over by said indicator on said dial,
said service wires each terminating as shown in a switch-wheel on its own switch-
board after sending off a branch to each of the other switch-boards in the system,
thus interconnecting all the switch-boards as aforesaid; all substantially as above.
set forth, and for the purpose of automatically placing the service wire of said
outlying station in electric circuit with any other service wire in the system at the
will of the operator at any outlying station.
3. In an automatic system of electrical intercommunication, a system of service-
lines converging from numbered (or otherwise designated) outlying stations to a
central point, each service wire terminating at a central point in as many normally
open branches as there are outlying stations in the system, one of said branches
connected to its own switch-board, the other branches each terminating in a
contact-point (bearing the number of the outlying station from which it runs) on
one of the other switch-boards, all switch-boards being thus grouped and inter-
changeably interconnected by each having a suitable contact-point terminal of
every service-line in the system (except its own), said contact-points being so
disposed about the switch-wheel as to be successively circuited with the switch-wheel
and its service-wire, because of a contact-spring in circuit with and carried by said
switch-wheel making contacts with each of said contact-points in succession as.
said switch-wheel is revolved, in combination with a system of switching-wires
converging from each of the same outlying stations to the same central point (said
switching system being in no manner electrically connected with said service system),.
each switching wire passing at a central point through an electro-magnet to a
common grounded battery and furnished at its outlying-station-end with a normally
open ground connection and suitable mechanism for making and breaking the same
for the purpose of sending through an electro-magnet a determinate number of
electrical impulses, thus by the action of a suitably constructed spring-controlled
armature to said electro-magnet propelling the switch-wheel forward a determinate
number of steps, carrying its contact-spring to desired contact-point with any other
desired service-wire; substantially as set forth.
4. In automatic electro-mechanical switches, a switch-board having a centrally-.
located switch-wheel connected to a wire capable of being grounded through a
service instrument at a point more or less remote, and carrying a contact-spring,
which, as said switch-wheel rotates, makes contacts with each one in succession of
any desired number of metallic contact-points, which are insulated from each other
and so disposed about said switch-wheel as to be in the path of said moving contact.
spring, each of said contact-points being the terminus of a service-wire, grounded
at a more or less distant point, each being placed in electric circuit with the wire
connected to the switch-wheel when the contact-spring makes a contact with its
contact-point terminus; service-wires passing one from each service-instrument at
outlying station to central point and there ending in as many branches as there are
stations in the system, the arrangement of said branches being such that one runs
to the switch-wheel corresponding in number or destination to the station with
which it is connected, and each of the remaining branches runs to a contact-point
having the same number or designation on one of the remaining switch-boards; in
combination with the spring-controlled armature of an electro-magnet, said armature
being hinged or pivoted at one of its ends, and at the other end bifurcated so as to-
straddle the switch-wheel, said bifurcation being furnished with pawl-shaped points
adapted to engage the sloping teeth with which the periphery of the switch-wheel
is furnished, the adjustment of the parts being such that as the electro-magnet is

page_text: alternately energized and de-energized by the make and break of an electric circuit
passing through it, the alternate action of the magnet and the opposing tension-
spring causes the pawl-like points to engage the sloping teeth of the switch-wheel
and urge it forward with step-by-step movement, the steps being made alternately
by the action of the magnet and tension-spring, the adjustment being such that in 5
either position of the armature one or the other of its pawl-like points is in
engagement with the switch-wheel, and whenever the magnet is de-energized the
contact-spring is in contact with some one of the contact-springs or on a blank or
resting-point on the switch-board, all substantially as set forth.
Dated this 5th day of June 1893.
ABEL & IMRAY,
Agents for the Applicant.