Improvements in or relating to Indicating Electric Switches and Current Reversers.
Year: 1892

page_text: Date of Application, 18th June, 1892-Accepted, 8th Oct., 1892
COMPLETE SPECIFICATION.
Improvements in or relating to Indicating Electric Switches and
Current Reversers.
A communication by ALMON B. STROWGER and WALTER S. STRONGER, both
of the City of Chicago, in the County of Cook and State of Illinois, United
States of America.
I, GEORGE CECIL DYMOND, M. Inst. M.E., of the Agency for Foreign
Patent Solicitors, 6, Lord Street, Liverpool, and 6, Bank Street, Manchester,
both in the County of Lancaster, and 323, High Holborn, in the County
of Middlesex, 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 :-
This invention relates to switches and current reversers which control currents of
electricity, which currents intermittently energise polarised electro magnets, for the
general purpose hereinafter set forth.
One of the objects of this invention is to provide means by which the number of
line wires required to operate electrical and other exchanges can be reduced to the
least number possible, which means includes the introduction of oppositely polarised
electro magnets which serve to operate the mechanism of said exchanges in com-
bination with a means by which the positive and negative currents of electricity,
respectively, from and to an electric battery are automatically reversed when being
controlled to operate said magnets, as will be fully explained hereinafter.
These objects are attained by the mechanism illustrated in the accompanying
drawings, in which,
Figure 1 is a front elevation of one of the principal parts of the combination
necessary to form the new combined indicating electric switch and current reversing
key together with a connected electric battery.
Figure 2 is a side elevation of Figure 1.
Figure 3 is a front elevation of the switch and electric current reversing key
detached from Figure 1.
Figure 4 is a side elevation of Figure 3.
Figure 5 is a front elevation of the switch dial or base to which the several
operative parts of Figure 1 are attached, the key, Figure 3, and several other
parts being removed to show plainly the method of making electrical
connections.
Figure 6 is a side elevation of Figure 5.
Figure 7 respectively face and edge views of a contact disc from Figure 3, to
show insulating material at centre.
Figure 8 shows respectively front and edge views of spring contact brushes for
conveying electric current to and from key, Figures 1 and 3.
Figure is an electric exchange of the general construction embodied in an
application for a Patent in Great Britain No. 11424 of June 18, 1892, with the
exception that one of the electro-magnets shown in Figure 9 in the present
application for patent is of opposite polarity to the others which will be explained.
This exchange being shown in the drawings to illustrate the application of the
combined indicating electric switch and current reverser, for Figure 9 shows an
auxiliary switch which is operated in combination with the mechanism shown in
Figure 1, and is inseparably connected to it in the switching operation necessary to
operate the electrical exchange shown, by means of currents over but one line wire
for both switching and telephonic purposes. Similar figures and letters designate
like parts throughout the several views.
.

page_text: Since in manipulating this system of transmitting and utilising currents of
electricity for the purpose stated, the work is always done at the station where is
located the mechanism embodied in Figure 9; its several parts will now be
described and then their relation to the mechanism of Figure 9 shown. In
Figure 1 is a dial 1 made of some insulating substance similar to gutta percha.
Figures 5 and 6 show a stud pin 2 which projects outward from the central portion
of the dial and which pin serves as a journal or pivotal centre upon which is
mounted and revolves hub 3 of key 5, a screw 6, Figures 1 and 2, being screwed
into the outer end of the pin and serving to hold the hub in position on the pin,
when key 5 is revolved by the operator's fingers around the dial in the direction
indicated by the arrow, the operator's fingers grasping thumb knob 7, which is
made of an insulating material. The key 5 is of metal and is firmly secured to
hub 3. There is a contact disc 8 which is firmly secured to hub 3, so that disc 8
and key 5 are in electrical communication with each other. At 9 is a metal knob
which forms a contact point for key 5. At 10 is a metal knob secured to the outer
end of key 5, but is electrically insulated from the key, and this knob 10 is
connected by wire 11 to disc 12, Figure 7, which disc is between disc 8 and key 5,
disc 12 being secured to hub 3 by means of insulating material 13. Disc 8 is
connected electrically to binding screw 14 by means of spring brush 15, and disc 12
connected electrically with binding screw 16 by means of spring brush 17, both of
these brushes bearing against the discs and not attached thereto, and making a
rubbing contact when the discs are revolved.
An electric battery 18 has its positive pole P connected by wire 19 to wire B
which is connected by a series of metal contact heads 20 and 21, which heads have
their base firmly secured in the face of dial 1, the outer ends of the contact heads
being above the face of the dial. It will be noticed that contact heads 20 are
longer than 21. Figure 6, contact heads 21 are nearer the centre of the dial 1
than long contact heads 20, so that the connecting wire B forms a zigzag around the
rim face of the dial. Contact heads 23 and 24 are all connected in one circuit by
wire C, which wire is connected to the negative side N of battery 18 by
wire 22.
The connected heads 23 and 24 are not of the same height above dial 1.
Heads 20 and 23 are high and form a pair, each head transmitting an electric
current opposite to the other in polarity. For convenience of description, these
pairs of high contact heads will be numbered 20-23. Short contact heads 21
and 24 also form pairs, each head transmitting an electric current opposite to the
other in polarity, and these heads 21 and 24 which are in pairs will be designated
21-24. Figure 5 shows wire B in solid lines and wire C in dotted lines to
illustrate more clearly than is shown in Figure 1, the course of these wires around
dial 1, and their connection with the several contact heads so that the relative
position of these heads in the pairs for the positive and negative side of the battery
is successively reversed all around the circle of dial 1. Attached to binding
screw 14 is the line wire 25, which is connected to the exchange, Figure 9, and
this wire carries currents of electricity controlled by and reversed by key 5,
Figure 3.
Wire 26 from screw binder 16 leads to ground at 29. In Figure 9 is
an auxiliary switch consisting of a dial D around which revolves a switch arm E,
the end of the switch arm contacting with heads of metal which are insulated from
each other when secured to dial D, these heads being in pairs, the members of each
pair being situated diametrically opposite to dial D and connected by a wire
forming an electric connection. On one side of dial D, five of these heads are
connected to wires which are designated, respectively, beginning at the bottom of
dial D, Hu., T, U, Tel. and R, because these wires carry currents of electricity
directly to the magnets which respectively operate the hundreds, tens, units,
telephone and release mechanism, in the system of telephone exchange shown in
Figure 9. The switch arm E is attached to and moves with a ratchet wheel F
which wheel has ten teeth in this instance, and is revolved on a stationary pin by

page_text: means of successive thrusts of pawl F operated by a magnet I through the medium
of armature J and lever K, causing the outer end of arm E to successively and
intermittently contact each of the insulated heads around dial D.
Although the wheel E is provided with ten teeth, it is only necessary to use
half of them as the heads on the dial are connected in pairs, upon opposite
sides of the dial, so that it is only necessary to move the arm E half way
round the dial to establish communication with all of the wires leading from
the switch to the apparatus for operating the contact point of the exchange.
Binding screw 30 is connected electrically to arm E by wire M, thence through
the coils of magnet I thence by wire L to the centre of motion of arm E. In
Figure 9, magnets 35, 36, 37, 38, 39 and 40 are all similarly polarised so as to
be capable of being energised by a positive current of electricity which current
passes through the coils of magnet I without energising the same on account of
its polarity being opposite to that of the other magnets above mentioned. The
switch dial, Figure 9, has five double contacts which are marked successively and
respectively, Hu., T, U, Tel. and R which designations register with the five
pairs of the short contact heads 21-24 plainly shown in Figures 1 and 5. It will
be understood that the combination of dial 1, Figure 1 and dial D, Figure 9,
with switch arm E moving around dial D in unison with the successive inter-
mittent movements of key 5 of dial 1, forms an indicating switch mechanism, so
that the operator at dial 1 always knows exactly the wire which switch arm E is
in communication with by the position of key 5 on dial 1.
In the form of electrical exchange shown in Figure 9 (which, however, is only
shown for the purpose of illustrating one form of mechanism to which my
correspondents' current reverser is applicable, and not for the purpose of limiting
themselves to it as the only form to which the reverser is applicable) 41 is a
centrally located spindle which is rotatable upon its axis, and movable longitudinally
to a slight extent, and is provided at its upper end with a movable contact head 42,
which is adapted to be brought into contact with any one of the ends of the wires 43
in the table 44. This spindle is rotated upon its axis in one direction by means of
the pawls 45 and 46 which engage with the ratchet wheels 47 and 48 respectively,
and are operated by the magnets 38 and 37 respectively. The wheel 47 is of a
greater diameter than the wheel 48 whereby the spindle is rotated a lesser
distance by one thrust of the pawl 45 than when operated by one thrust of the
pawl 46. This is for the purpose of saving time in the rotation of the spindle as
the smaller ratchet wheel is operated for moving the contact head as for instance
over ten wire ends for each thrust of the thrust of the pawl and the other wheel
will only move it over one wire end. The spindle 41 is rotated in the opposite
direction by a spring 49 as soon as the pawl 50 is disengaged from the ratchet
wheel 47 by the magnet 35.
The contact head 42 is moved radially from the spindle by means of a longi-
tudinally movable rod 51 and an angle lever 52. The spindle 41 is moved upwards
by means of a rack gear 53 which is operated by the magnet 39, and held in its
elevated position by the pawl 56 which engages with the ratchet wheel 55 and
which can be released therefrom by the magnet 36 which will permit the rod to
fall and thus move the contact head 42 back to its original position. The
spindle 41 is moved longitudinally to prevent its contact head 42 from coming in
contact with the ends of the wires while it is being moved from one wire end to the
other by a lever 57 which engages with the lower end of the spindle, this lever 57
being swung on its pivot by the magnet 40. After all the electrical connections
are made with dial 1 from battery 18 and ground 29, Figures 1 and 2, and wire 25
is connected to binding screw 30, Figure 9, should key 5 be turned as a crank
around dial 1 from left to right, see arrow, the contact points 9 and 10 near the
end of key 5, would successively and simultaneously strike the top surface of each
one of each pair of long contact heads 20-23, but the contact points 9 and 10
would not strike the contact heads 24-21 on account of their top surface being

page_text: below the plane of revolution of key 5 and the top line of surface of contact
heads 20-23.
Suppose key 5 is in the position shown in Figure 1, the contact points 9 and 10
are out of contact with the heads on dial 1. If the key 5 is turned to the right,
direction of arrow, until contact points 9 and 10 strike contact pair 20-23 at the
top of the dial, Figure 1, a negative current of electricity will pass from binding
screw 41, Figure 9 (which binding screw is connected with the ground) thence by
wire to and through the coils of magnet 40, thence to binding screw 42, thence
by wire R to and through the coils of magnet 36, thence by wire R to and through
the coils of magnet 35, thence by wire R to contact head Ŕ of dial D, thence switch
and wire L and through the coils of magnet I, thence by wire N to binding screw 30,
thence by line wire 25 to binding screw 14, Figure 1, thence through brush 15 to
disc 8, key 5, contact point 9, contact head 23, thence by wire C to and through
wire 22 into the negative side N of the battery 18, thence by wire 19 to wire B, of
dial 1, thence by head 20 into the insulated point 10 of key 5, thence by wire 11,
disc 12, and brush 17 to binding screw 16, wire 26 and to ground 29. During the
passage of this negative current only magnet I, Figure 9, is energised, which causes
pawl F of lever K to turn ratchet wheel F the pitch of one tooth thereof, causing
switch arm E to move in the direction of the hands of a watch, and contact the next
contact head of dial D. Should key 5 be revolved around dial 1, each time its
contact point strikes contact heads 20-23, a negative current will pass through
the coils of magnet I toward battery 18, in the manner described, when the
several parts of the mechanism have the relative position as shown and described.
Each time magnet I is energised arm E is caused to move forward and contact the
next succeeding contact head of dial D, Figure 9, the movements of arm E being
practically simultaneous with the movement of key 5, so that arm E is at all times
in the same relative position as to contact at dial D, as key 5 is at dial 1.
The course taken by a negative current of electricity when serving to energise
magnet I of auxiliary switch, Figure 9, has been shown and now the means will be
described by which the electric current is reversed at dial 1. Figure 1, so that a
positive current is conducted from battery 18 through line wire 25, then shunted to
any one or more of the magnets separately of the operative mechanism of the
exchange Figure 9.
After key 5 has been turned over and out of contact with the heads 20-23 at
the top of dial 1, and switch arm E has moved to the next succeeding contact head
on dial D, it will be found that a current of electricity can pass from line wire 25,
to the hundreds magnet 39 of Figure 9. If key 5 is stopped in its movement
directly over the pair of contact heads 21-24, which heads have Hu. between them,
Figure 1, a positive current from battery 18 can be sent through to hundreds
magnet 39 by pressing against the top of insulated knob 7, the outer end of key 5
will be bent inward toward dial 1 and contact points 9 and 10 will strike against
contact heads 21-24 when a current of electricity from the positive side of
battery 18 will pass through wire 19, wire B and contact head 21, thence through
contact head 21, thence contact point 9, key 5, disc 8, brush 15, binding screw 14
and thence through line wire 25 to binding screw 30, Figure 9, thence through the
coils of magnet I without energising said magnet, thence by wire L, switch arm E,
contact head Hu., thence by wire Hu. to and through the coils of magnet 39 (which
is energised) thence to binding screw 42, thence through the coils of magnet 40,
thence to the ground by connected binding screw 41.
Key 5 is pressed down with points 9 and 10 in contact with 21-24 at Hu. as
many times as it is necessary to operate the hundreds mechanism of the exchange.
In case the 'tens' mechanism of the exchange is to be operated, a further move-
ment of key 5 around dial 1 from Hu. direction of arrow, will cause contact points 9
and 10 of key 5 to contact with the next pair of heads 20-23 which will set switch
arm E, Figure 9 to T of tens, after which key 5 is turned to stand over contact
heads 21-24 having T between them, when key 5 is pressed down with the points 9

page_text: and 10 in contact with heads 21-24 as many times as is desired for the required
number of tens' and so on for units' telephone' and 'release.'
Having now particularly described and ascertained the nature of the said
invention and in what manner the same is to be performed, as communicated to
me by my foreign correspondents, I declare that what I claim is-
1. A combined indicator, switch and current reverser, consisting of an indicator,
a series of pairs of contact heads, the heads of each pair being adapted to be con-
nected with the opposite poles of a battery, and a switch movable over said heads
and adapted to be brought into contact therewith and provided with means for
reversing the current, substantially as set forth.
2. A combined indicator, switch and current reverser consisting of a dial, an
annular series of pairs of contact heads secured thereto, the heads of each pair being
adapted to be connected with the heads of the other pairs and with the opposite
poles of a battery and a switch pivotally secured at the centre of said dial and
series of heads, and provided with means for reversing the current, substantially as
set forth.
3. A combined indicator, switch and current reverser consisting of a dial, two
rows of contact heads arranged in pairs, the heads of each pair being adapted to be
connected with the heads of the other pairs and with the opposite poles of a battery,
the polarity of the heads of cach row alternating with each other, and a switch
movable over said heads and adapted to be brought into electrical connection there-
with, whereby a current may be passed in either direction, through the heads and
their connections, substantially as set forth.
4. In a combined indicator, switch and current reverser, the combination with an
electric battery, a series of pairs of contact heads secured thereto and arranged in
two circles around the dial, the heads of each pair being connected with the opposite
poles of a battery, and the polarity of the heads of each row alternating with each
other, two wires secured to the dial, one of which is a ground wire, and the other is
a working wire, a switch pivotally secured at the centre of the rows of heads
provided with two insulated contact points, each of which connects with the central
portion of the dial, and an electrical connection between each of the contact points
of the switch and each of the wires secured to the dial substantially as set forth.
5. In a combined indicator, switch and current reverser, the combination with a
dial of a central pivotal point and a series of metal contact heads arranged around
the disc in two concentric rows, the alternate heads of the rows being of different
lengths, a flexible key pivotally secured upon the central pin and provided with two
contact points at its free end, one for each row of contact heads, an electric battery,
two wires leading therefrom and connecting the heads alternately, and means for
establishing electrical communication with the contact points of key, and with wires
leading from the dial, substantially as set forth.
6. In a combined indicator, switch and current reverser, the combination with a
battery of a dial, a central pivotal pin, and a series of contact heads arranged in
pairs in two circles around the dial, the head of each pin being connected with the
opposite poles of a battery, and the polarity of the heads of each pair alternately
with each other, two discs and a key upon the central pin, the discs being insulated
from each other, one of which is communicated with one of the discs and the other
one with the other disc, and two brushes for engaging with said plates and
establishing connection with wires from the other disc, substantially as set forth.
7. In a combined indicator, switch and current reverser, the combination with an
electric battery of a disc provided with a central pin, and a series of contact heads
arranged in pairs around the dial, the alternate pairs of heads being of different
heights above the face of the dial, and the heads of each pair being connected with
the opposite poles of the battery, and the polarity of the heads alternating with
each other, two discs and a flexible key secured to the central pin, the discs being
insulated from each other, one of the points communicating with one of the discs

page_text: and the other one with the other disc, a knob on the key for forcing the free end
inward to contact with the shorter heads, two binding posts on the dial, and a brush
secured to each post, and contacting with the dises respectively, substantially as set
forth.
8. The combination with an automatic electrical exchange provided with a series
of magnets for operating same, the polarity of one of which is different from the
others, of a combined switch and current reverser, substantially as set forth.
9. The combination with an electrical exchange provided with a series of magnets
for operating the same, and with a dial, one of the magnets being of a different
polarity from the others, of a combined indicator, switch and current reverser
connected therewith, whereby alternate currents may be passed through the magnets
of the exchange, substantially as set forth.
10. The combination with an automatic electrical exchange provided with a series
of magnets of one polarity, of a distributing switch, a magnet for operating the
same, of a different polarity from the other magnets and means for passing different
currents through said magnets and switch substantially as set forth.
11. The combination, with an automatic electrical exchange provided with a series
of magnets of one polarity, of a switch connected therewith, said switch being
provided with contact heads electrically connected in pairs, an arm for engaging
said heads, a magnet electrically connected with said arms of a different polarity
from the other magnets, and means for passing different currents through said
magnets and switch substantially as set forth.
12. The combination with an automatic electrical exchange provided with a series
of magnets of one polarity, of a switch connected therewith having contact heads
electrically connected in pairs, an arm for engaging with said heads a magnet
electrically connected with said arm of a different polarity from the other magnets
and a current reverser for passing different currents through said magnets and switch,
said reverser having as many reverse contact points as there are pairs of heads
upon the switch, substantially as set forth.
Dated this 17th day of June 1892.
WM. P. THOMPSON & Co.,
Agents for the Applicant.