Improvements in Switch Boards for Telephone Systems.
Year: 1889

page_text: Date of Application, 6th Aug., 1889
Complete Specification Left, 6th May, 1810-Accepted, 7th June, 1890
PROVISIONAL SPECIFICATION.
Improvements in Switch Boards for Telephone Systems.
I, JOHN RANDOLPH SMITH of Block 1, Abbott's Addition, corner of Hamilton
Street, and Franklin Avenue, Neosho, Newton County, State of Missouri, United
States of America, Physician do hereby declare the nature of this invention to be as
follows:-
The object of the invention is to provide a switch board specially adapted for
telephone systems, which will enable any subscriber to make a direct connection with
any other subscriber in the system without the intervention of a third party at a
ceutral office.
The invention consists of an automatic device adapted to connect any two tele-
phones in the system with each other.
The switch will be described as arranged for three subscribers only, but it is
evident that it may be constructed on the same principle for an indefinite number.
The frame of the switch board is L-shaped and carries on its upright part sets of
magnets according to the number of subscribers in the telephone system. Each set
of magnets is respectively connected by wires with the subscribers stations and each
station is provided with the usual telephone instrument and with a dial. Each dial
has an insulated crank arm with which one end of the wires is connected the other
end of the wires being connected with the rim of the dial. The crank arm is adapted
to pass on to projections corresponding in number to the number of subscribers in
the telephone system, and numbered consecutively. When the crank arm is moved
on one end of the projection, a complete circuit is established in the wires, the
electric current passing through the dial, its respective projection, to the crank arm,
and from the latter to the other part of the wire. A pawl prevents the arm being
turned in the wrong direction and it may be held in position by a stop pin.
In the wires between their respective magnets and the stations is the usual battery
for supplying the necessary electric current and in connection with each magnet
there is an armature secured to a lever fulcrumed on the frame and held out of
contact with the magnet by a spring. The movement of the upper end of the lever
is limited by stops in the usual manner.
On the lower end of each lever there is a pawl adapted to engage a ratchet wheel
on a cylinder mounted to turn in bearings on the frame. On each cylinder rest the
free ends of sets of levers which I will term N, N', and N2, respectively, each set
being mounted on a shaft held in bearings on the frame. The shafts are connected
by wires with the station wires between the battery and the station.
Said
Each set of levers N, N¹ and N2 comprises double the number of levers, less two,
of the number of subscribers in the telephone system, and consequently in this case
there are four levers which I will term 0, 0, 02 and 0 in each set each provided on
its underside with a projection travelling on the periphery of its cylinder.
projections are adapted to engage notches arranged in sets on the periphery of the
cylinders, the levers 0 and being adapted to drop simultaneously with their
projections in one pair of notches, the levers and 03 to drop simultaneously in
another pair of notches; while the levers 02 and 03 are adapted to drop simul-
taneously with their projections into a double notch.
The free ends of the sets of levers N. N¹, and N2 pass into bridges, and the said
outer ends are adapted to make contact with wires connecting the several bridges
with each other.
The operation is as follows: When the several telephone instruments of the
subscribers are not in use, the levers stand on the respective number of the sub-
scriber, that is to say the lever of No. 1 dial stands on 1, that of the No. 2 dial on the

page_text: numeral 2, and that of the No. 3 dial on the numeral 3, that is to say, the numeral
of the first subscriber is 1, that of the second is 2, that of the third is 3, and as long
as the telephone is not in use the crank arm of its dial must stand at its numeral.
Now, if the subscriber at station No. 1 desires to make connection with the
subscriber at station No. 2 for instance, then the subscriber at the dial No. 1 turns
his crank arm until it stands at the numeral 2: that is, the numeral of the subscriber
at the second station. This operation breaks the circuit passing through the dial
once, so that the magnet operates its armature once and consequently the cylinder is
shifted one-third; that is, the distance of one tooth on the ratchet wheel, whereby
the levers 0 and 0 of the sets of levers N drop with their projections in the notches
of the cylinder, so that the said levers make connections with the wires leading to the
bridge of the set of levers N¹. In the latter the two levers 0 and 0 are SO
connected that the electric current passes to the shaft of the set of levers X and
thence to the subscriber's station No. 2, thus completing the circuit between the
station No. 1 and No. 2. The subscriber at station No. 1 now rings up the
subscriber No. 2 and when the latter steps to his telephone No. 1 tells him he wants
him. But the subscriber No. 2 is liable to be called up by the subscriber No. 3,
and in order to avoid this the operator at the station No. 2 turns the crank arm to
the numeral 1: that is to the numeral of the party in station who called him. By
doing this the subscriber at No. 2 station breaks the electric circuit twice, whereby
the armature is twice actuated and shifts the cylinder two thirds, so that the levers
and 0 drop with their projections into their proper notches on the said cylinder.
Both levers 0 and 0° connect with the wires leading to the bridge of the set of
levers N and as the lever 0 of the set of levers N is connected by wire an electric
circuit is still established between stations Nos. 1 and 2, but neither can now be
called by station No. 3 as no connection can be made between the levers N° and
levers Nor N¹.
When the two subscribers connected with each other have finished, they return
the respective crank arms of their dials to their own numbers marked on the dials
and are thus ready to be called or call again.
It will he seen thai a thousand subscribers more or less, may be thus paired
and talking at the same time without interfering with each other. If a subscriber
turns to a number which is engaged with another subscriber, he is immediately
informed of this fact by his hell not ringing, and has either to wait or turn back to
his own number.
Dated this 6th day of August 1889.
COMPLETE SPECIFICATION.
Improvements in Switch Boards for Telephone Systems.
I, JOHN RANDOLPH SMITH of Block 1, Abbott's Addition, corner of Hamilton
Street, and Franklin Avenue, Neosho, Newton County, State of Missouri, United
States of America, Physician, 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:-
The object of this invention is to provide a switchboard, specially adapted for
telephone systems, which will enable any subscriber to make a direct connection
with any other subscriber in the system without the intervention of a third party at
a central office.
The Invention consists of an automatic device adapted to connect any two telephones
in the system with each other.
The Invention also consists of certain parts and details and combinations of the
same as will be hereinafter fully described and then pointed out in the claims.

page_text: Figure 1.
Reference is to be had to the accompanying drawings, forming part of this
specification, in which Figure 1 is a front view of the improvement as applied to a
telephone system. Figure 2 is a sectional plan view of the same, on line
Figure 3 is a transverse section of the same on line yy, Figure 1. Figure 4 is an
enlarged front view of one of the cylinders and adjacent parts. Figure 5 is a
transverse section of the same. Figure 6 is an enlarged face view of one of the dials;
and Figure 7 is a transverse section of the same. Similar letters of reference indicate
corresponding parts in all the figures.
As shewn in the accompanying drawings, the switch-board is arranged for three
subscribers only but it is evident that it may be constructed on the same principle
for several thousand.
The switch board has a suitably constructed frame A preferably L-shaped and
carrying on its upright part sets of magnets B, B', B², etc., according to the number
of subscribers in the telephone system. Each set of magnets is respectively con-
nected by the wires ab, a, a²², with the subscribers stations C. C, 03. Each
station is provided with the usual telephone instrument E, E, or E2 and also with
a dial F, F, or F2 as is plainly shewn in Figure 1. Each dial F has an insulated
crank urm G (see Figures 6 and 7) with which one end of the wires a al a² is con-
nected, the other end of the wires being connected with the rim of the dial. The
crank arm G is adapted to pass on to projections corresponding in number to the
number of subscribers in the telephone system and numbered consecutively 1. 2. 3.
fe, as illustrated in the drawings. When the crank arm G is moved on one end
of the projection, a complete circuit is established in the wires « a a² the electric
current passing through the dial, its respective projection, to the crank arm and
from the latter to the other part of the wire. G is a pawl on the outer end of each
crank arm adapted to engage teeth G on the periphery of the dial and prevent the
operator from turning the crank arm G in the wrong direction. A pin may be
inserted in an aperture formed in the dial alongside each projection so as to stop the
crank arm G in the proper place on the desired projection.
In the wires b b¹ between their respective magnets and the stations C is arranged
the usual battery D for supplying the necessary electric current. In connection with
each magnet B B B2 there an armature H H or HP secured to a lever I ]¹ or 12
fulcrumed on the frame A and held out of contact with the magnet by a spring 13,
as shewn in Figure 3. The movement of the upper end of the lever is limited by
stops in the usual manner. On the lower end of each lever I ] or 12 there is a
pawl J, J, or J, adapted to engage a ratchet wheel K K or K² formed on a cylinder L.
Lor mounted to turn in bearings on the horizontal part of the frame A. see
Figures 4 and 5. On each cylinder L. L', or L rest the free ends of sets of levers N
Nand N2 respectively, each set being mounted on a shaft N3 held in bearings on
the upright part of the frame A, as shown in Figure 3. The shafts No are connected
by wires e and with the wires and respectively, between the battery D and
the station C C or C respectively. Each set of levers N N and N2 comprises
double the number of levers, less two, of the number of subscribers in the telephone
system, and, consequently, in this case, and as shewn in the drawings, four levers
002 and 03 are held in each set of levers N N N². Each of the said levers 0 0¹
02 and 03 is provided on its under side with a projection travelling on the
periphery of its cylinder L, L' or L². Said projections are adapted to engage
notches L L and L arranged in sets on the periphery of the cylinders L L'or L².
As is plainly shewn in Figure 4, the levers 0 and 02 are adapted to drop simul-
taneously with their projections in the sets of notches L; the levers 0 and 03
are adapted to drop simultaneously in the sets of notches L'; while the levers 02
and 03 are adapted to drop simultaneously with their projections in the double
notch L. The free ends of the sets of levers N. N¹, and N2 pass into the bridges Q
Qand respectively, and the said outer ends are adapted to make contact with
wires connecting the several bridges with each other, in the manner shewn in
Figures 1 and 2 presently to be described; that is, a wire R is adapted to connect the

page_text: lever O of the set of levers N with the lever 03 of the set of levers N¹; a wire-P
is adapted to connect the lever O' of the set of levers N with the lever 0% of the set
of levers N2; a wire P is adapted to connect the lever 02 of the set of levers N
with the lever 01 of the set of levers N¹; a wire P³ connects the lever 03 of the set
of levers N with the lever 0 of the set of levers N° a wire P is adapted to con-
nect the lever 03 of the set of levers N with the lever 0 of the set of levers N¹;
and a wire P is adapted to connect the lever of the set of levers N° with the
lever 02 of the set of levers N¹
The operation is as follows: When the several telephone instruments of the
subscribers are not in use, the levers G stand on the respective number of the sub-
scriber, as is plainly shewn in Figure 1 in which the lever G of the dial F stands
on 1 that of the dial F¹ on the numeral 2 and that of the dial F on the numeral 3.
that is to say the numeral of the first subscriber is 1 that of the second is 2 that
of the third is 3, and as long as the telephone is not in use the crank arm of its dial
must stand at its numeral. Now, if the subscriber at station C desires to make
connection with the subscriber at station C', for instance, then the subscriber at the
dial turns his crank arm G until it stands at the numeral 2; that is, the numeral
of the other subscriber at the station C¹ This operation breaks the circuit passing
through the dial once, so that the respective magnet 13 operates its armature H once
and consequently the cylinder L is shifted one-third, that is the distance of one
tooth on the ratchet wheel K whereby the levers 0 and 02 of the set of levers N drop
with their projections in the notches I so that the said levers 0 and 02 make
connections with the wires P and P leading to the bridge Q. In the latter, as shewn
in Figure 1, the two levers 02 and 03 are connected with the wires P and P
respectively so that the electric current passing through the wires P passes to the
shaft N3 of the set of levers N' and through the wire c¹ to the subscribers' station C¹
thus completing the circuit between the stations C and C. The subscriber at station C
now rings his bell so that the bell at the subscribers' station C¹ is sounded and
when the subscriber at C steps to his telephone the subscriber at C tells him that
No. 1 wants him. But the subscriber at station C is now liable to be called up
by the subscriber at station C2, and, in order to avoid this, the operator at the
station C¹ turns the crank arm G of the dial F¹ to the numeral 1; that is to the
numeral of the party in station C who called him. By doing this the subscriber at C¹
breaks the electric circuit. twice whereby the armature His twice actuated and
shifts the cylinder 1 two thirds so that the levers O and 0 drop with their
projections O into the set of notches L' on the said cylinder L. Both levers O¹ and 03
connect with the wires P and P2 leading to the bridge Q and as the lever of the
set of levers N is connected with the wire P an electric circuit is still established
between stations C and C' but neither station C nor station Ct can now be called by
station Cas no connection can be made from station 2 by the levers in the set of
levers N2 with either set of levers N or N¹.
When the two subscribers connected with each other have finished, they return
the respective crank arms G of their dials to their own numbers marked on the dials
and are thus ready to be called or to call again.
It will be seen that a thousand subscribers, more or less, may be thus paired
and talking at the same time without interfering with each other. If a subscriber
turns to a number which is engaged with another subscriber he is immediately
informed of this fact by his bell not ringing and has either to wait or turn back to
his own number.
Having now particularly described and ascertained the nature of the said inven:
tion and in what manner the same is to be performed I declare that what I
claim is
1. In a telephone switchboard, a device adapted to automatically connect any two
telephones in the system with each other, substantially as shewn and described.
2. A telephone switchboard comprising a series of cylinders mounted to turn and

page_text: a series of levers resting on the said cylinders and adapted to be electrically connected
with each other according to the movement of the said cylinders, substantially as
shewn and described.
3. A telephone switchboard comprising a series of cylinders mounted to turn, a
series of levers resting on the said cylinders and adapted to be electrically connected
with each other according to the movement of the said cylinders and series of electro-
magnets connected with the telephone instruments and controlling the movement of
the said cylinders, substantially as shewn and described.
4. A telephone switchboard comprising a series of cylinders mounted to turn, a
series of levers resting on the said cylinders and adapted to be electrically connected
with each other according to the movement of the said cylinders, series of electro-
magnets electrically connected with the telephone instruments in the system and with
the pivots or shafts of the said series of levers and series of pivoted armatures
controlled by the said magnets and controlling the movement of the said cylinders,
substantially as shewn and described.
5. A telephone switchboard, comprising a series of cylinders mounted to turn, a
series of levers resting on the said cylinders and adapted to be electrically connected
with each other according to the movement of the said cylinders, series of electro-
magnets connected with the telephone instruments and controlling the movement of
the said cylinders, and a series of dials adapted to open and close the electric circuit
of the telephone instruments and the respective electro-magnets, substantially as
shewn and described.
6. The combination, with the switchboard, substantially as described, of two wires
leading from the switchboard to each telephone station and a telephone instrument
and a dial located together and placed on the said wires, substantially as shewn and
described.
7. The combination, with the switchboard substantially as described, of two wires
leading from the switchboard to each telephone station, a telephone instrument and a
dial located together and placed on the said wires, and a crank arm held in each of the
said dials and adapted to open and close the circuit, substantially as shewn and
described.
1000