Improvements in Electric Selectors and Adaptations thereof, and in Transmitters suitable therefor.
Year: 1896

page_text: Date of Application, 1st Sept., 1896-Accepted, 28th Sent., 1898
COMPLETE SPECIFICATION.
[Communicated from abroad by ELECTRIC DETECTOR AND SIGNAL COMPANY,
of 46, Broadway, in the City of New York, U.S.A.]
Improvements in Electric Selectors and Adaptations thereof, and in
Transmitters suitable therefor.
I, THEODORE MCKENNA of 17 and 18 Basingball Street in the City of
London, Solicitor 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 :-
The apparatus described in the following specification is as the above title
insports an electrical selecting instrument, designed to be used in connection with
an impulse transmitting instrument, capable of transmitting impulses of opposite
polarities and responds to a certain and fixed combination of such impulses, aud
when a number of such selectors, each responding its own combination are placed
upon a live its office is to select or pick out the station, telegraph, telephone, or
other instrumentality to which its own combination applies aud no other: and in
conuection with this selector the invention also covers a transmitting instrument
adapted to be used therewith.
The accompanying drawings will illustrate the invention of which
Figure 1 is a side elevation of the selector.
Figure 2, a plan or top view of eame.
Figure 3, a view of the device with the armature operating to lift one of the
retaining pawls leaving the other to hold and retain the wheel in position.
Figure 4, a view of the retaining pawls, both lifted to release the wheel and
allow it to return to starting point.
Figure 5, a view of the inpelling wheel and spring for returning the instrument
to starting point.
Figure 6, a plan view of a transmitting instrument.
Figure 7, a side view of same.
Figure 8, an edge view of the wheels of the transmitter.
Figure 9, a diagram of the selecting instruments connected with mechanical
devices.
Figure 10 is a side elevation of the selecting instrument, as modified.
Figure 11, a top or plan view of the saine.
Figure 12, a view of the sector and retaining pawls showing one of the pawls
thrown out whilst the other holds the sectors.
Figure 13, a view of the same with both retaining pawls thrown out and the
wheels returned to starting point.
Figure 14, a view of the selecting instrument and mechanical device in normal
position.
Figure 15, a view of the sector and mechanical device when both have arrived
at the end of their phase movements.
Figure 16, a view of the mechanical device caught and hold in position whilst
the selector is returned to starting point.
Figure 17, a view of the action of the selector in releasing the mechanical
device and showing that device returned to starting point.
Figure 18, a modified form of selecting instrument and guiding device in normal
position.

page_text: Figure 10, the same showing position of retaining pawls and guiding device to
throw out one of the pawls and leave the other to hold the sector.
Figure 20, the same showing both retaining pawls. thrown out.
Figure 21 shows the polarized magnet. attached to pawl-hanger and a stationary
projection to guide it to throw out pawls.
Figure 22 represents a top or plan view of another modified form of selector.
Figure 23, a side upright view of the same.
Figure 24, a view of a polarized relay and local battery, showing the connections
with the binding posts 1, 2, 3.
Figure 25 is a plan view of transmitter adapted for use with any of the forms
of selector.
Figure 26 is a front view of the same.
Figure 27, an end view of the same looking at the right of Figure 1.
Figure 28, an end view looking at the left of Figure 1.
The selectors are intended to be operated by the transmission of electrical
impulses sent out by a suitable, transmitter or by the ordinary telegraph key or a
pair of keys so arranged ns to be capable of transmitting currents of opposite
polarity.
Viewing Figures 1 to 5
Upon a suitable base as A, are erected the standards A', which are properly
jourualled or countersunk to receive the ends of the shaft A 2, and on this shaft is
secured the armature B. A magnet as C is provided with convex pole pieces,
whose curve conforms to the rounded ends of the armature.
The device may be constructed with either the magnet or the armature
polarized; that is to say, if constructed with a polarized magnet, then the
armature should be wound so that currents transmitted through the coils
will turn the armature to one pole or the other of the magnet, according to the
polarity of the current transmitted; if the armature be polarized the magnet
should be constructed as an electro-magnet to attract the armature to either side
according to the polarity of the impulse transmitted through its coils. As the
operating devices of the apparatus must co-act with each other it is desirable that
the armature should have a throw of fixed length, and for this purpose any
suitable arrangement of stops may be used; in the drawings these stops are
shown as plugs bb, which strike against the ends of the pole-pieces and thus limit
the stroke of the armature on each side; there should also be a provision for
returning the armature to normal position between the impulses or at tines when
the current is off'; a good device for attaining this end is shown in the drawings;
a bar a 3 is secured to the shaft A 2, whose free end plays against the spring b2,
whose action is always to keep the armature in normal position when not responding
to an impulse.
Secured to the shaft A 2 is the crank or arm D, which works with the armature,
this crank is provided with the pin d', to which pin is pivoted one end of the
pawl d 2.
Suitably journalled in the frame-work is the shaft E, to which are secured two
wheels F and F. The wheel F is constructed with an indented or toothed periphery;
into these teeth the hook d3 on the free end of the pawl d 2 drops and turns the
wheel in obedience to the impulses, and is raised up at proper intervals, to take
hold of another tooth, or to release the wheels of all the selecting instruments not
specially called, and also to restore the instrument called to starting point when
its work is done.
There is also pivoted to the frame-work of the apparatus two retaining
pawls 2, 3, whose function is to check and hold the wheels until thrown out at
the proper time; 2 operates on the wheel F, and f3 on the wheel F; the
wheel has its teeth succeeding each other around the entire circumference or
around so much of it as may be necessary, and is the whoel which is impelled by
the pawl; it may be constructed in the form of a bar or sector. The wheel FI
has a few notches arranged to suit a predetermined arrangement of impulses and

page_text: may be called the combination wheol, and the two co-operate together and perform
their work as follows:
A series of impulses transmittel consecutively in one direction would turn the
wheel F on the selected instrument as well as the wheels on all of the other
selecting instruments through their entire courses, and the theory upon which the
instruments work is to turn the wheel of the selected instrument by means of the
impulses and at intervals during the course of its revolution to throw back to zero
or starting point the wheels of all the selecting instruments on the line except the
one specially selected, which must complete its phase, and is only thrown back at
the end of it; and this is effected by the following instrumentalities; as the
wheel F is provided with teeth or notches around its periphery; so the wheel F¹
is provided with a smooth surface upon which its pawl rides, except here and there
a notch into which its pawl may drop when required, any one of the notchos of
the wheel Finay be selected as a starting point, and from this point the notches
are calculated on the wheel F to form the combination of the selecting instrument;
for example, let us suppose that we desire a particular selecting instrument to
respond to the following combination of impulses 5-4-5, as shown in Figure 1;
then on the wheel F a notch would be made at the proper distanco from the
starting point to allow the pawl to drop when five impulses had been transmitted in
a given direction to impel the wheel five teeth, from this point another notch
would be placed on the wheel F' at the distance of four notches on the wheel F,
and then another would be placed at the distance of five notches, thus the
retaining pawl on the wheel F would drop into a notch at each impulse whilst the
retaining pawl of would only drop into the notches at five impulses, then four,
and then five, at each of these drops of the pawl the instrument is arranged to
receive an impulse of opposite polarity, and this impulse will restore all the other
instruments than the oue selected to starting point.
The arm d 2 (Figure 1) is provided with the extension d 6, which strikes against
the retaining pawls to release the wheels; the pawl 3 is so constructed that when
it is dropped into a notch the extension d 6 will ride over its top without disturbing
it, but when it is raised out of the notch and is resting on the plain surface of the
wheel, the extension d6 will strike and throw it out, whilst the pawl 2 is so
constructed that when the impulse is given in the opposite direction it is always
thrown out, but when this impulse is given and the pawl f2 is thrown out, the
pawl f3 is in its notch of the selected instrument and escapes the action of the
projection d 6, remaining in its place and retaining the wheel in position; thus it
will be seen that in order to restore the instrument to zero it is necessary that the
pawl f3 be out of its notch and resting on the raised surface of the wheel so that
the projection d6 will lift both pawls as shown in Figuro 4, and allow the
returning spring to restore the instruments to zero. A box H, located for
convenience between the wheels, contains the returning spring; in propelling the
wheel to complete its phase this spring is wound and when the pawls are released
from the wheels the re-action of this spring restores them to starting point.
It is easy to see that the combination of the instruments not selected for
operation may be so arranged that the pawls of all of them will be in position to
be released and returned by the roverse impulse, except the one selected for
operation, that is to say, that the pawl f3 will be resting on one of the raised
surfaces of the wheel ; and when this instrument has completed its course the
pawl 3 rides upon the raised surface when au opposite impulse will restore it.
It will also be seen from the construction of the device that any two succeeding
impulses of opposite character will restore all the instruments to zero, hence at the
end of each phase or combination, succeeding impulses of opposite polarity are
transmitted to restore the instruments, and these may be called the unisoning
impulses.
Upon the shaft which carries the wheels is placed the cam J, which turns with
the shaft and wheel; it is usually constructed of some insulating material and
when the instrument has completed its phase, closes the brushes and i'. With

page_text: the ordinary uses for call bells for telephone or telegraph work such as are shewa
in Webbs arrangement in the Letters Patent granted under No. 5412 of 1896,
the contact of these brushes closes a circuit through the call bell and rings it;
the device may also be used to advantage in selecting and operating a mechanical
device, as shown by the diagram Figure 9, in which 1 shows the transinitting
instrument; 2, 3 and 4 the selecting instruments, and 5, 6 and 7 the mechanical
devices each connected with a selecting instrument. It will be observed that the
brushes and on each of the selecting instruments as shown on the diagram
Figure 9 are open, and that the current passes through each of the selecting
instruments until the brushes i and on a selectel one are brought in contact, the
current is then shunted through these brushes to the mechanical device in
connection therewith, that is to say, when the brushes on No. 2 selecting instrument
are contacted, the circuit is closed through the mechanical device No. 5, when
brushes of No. 3 selecting instrument are contacted, No. 6 mechanical device is
brought into circuit, and so on. Each of these mechanical devices is provided
with its electro magnet and armature lever as usual for operating the mechanical
device, and as the armature lever will respond to impulses of either polarity, so
when the selecting instrument has completed its phase and has been netuated by
impulses of oue polarity, all impulses thereafter sent out of opposite polarity will
leave the selecting instrument standing still, and these opposite polarity impulses
are then used to operate the mechanical device whilst the selecting instrument is
held in place with the circuit in the mechanical device closed through the brushes i
and 7. When the work is done the selecting instrument is returned to starting
point by an impulse of oue polarity followed by one of opposite polarity as already
described; and the same operation is truc of other instrumentalities than a
mechanical device and will apply equally to electrical instrumentalities as well
as mechanical. So long as the instrument is connected by means of the selector to
the same transmitter, and that transmitter is then required to do some other work
upon the instrument thus connected, that work should be done by impulses of a
polarity opposite to those which turn the wheels.
In connection with the operation of selecting instruments by the use of currents
of opposite polarities I have devised an automatic transmitter and provided it with
appliances by means of which any selecting instrument of that character (whether
the armature performs its work by movements in alternate or opposite directions
or by movements in the same direction) may be operated without professional or
expert skill; it consists of two disks placed together on a shaft which by means of
a spring turns the shaft and disks one revolution; one of these disks is provided
with teeth of conducting material, and the other with teeth of insulating material,
or the entire wheels may be made, one, of conducting and the other of insulating
material.
Figures 6, 7 and 8 illustrate a transmitting device; upon a suitable shaft are
placed the two disks; K the conducting disk, and K the insulated disk; a
handle is connected with a shaft L, and when turned winds up a spring,
whose recoil turus the diske through suitable gearing connections with the shaft
upon which the disks are mounted. The teeth of conducting material may be
called contacts, and transmit the impulses of the required polarity to operate a
selected instrument to the end of its phase, and the teeth of insulating material
perform several functions; first-at the end of each member of the combination
as arranged upon a particular instrument, they make conuections and close circuits
to transmit impulses of an opposite polarity to those which impel the selecting
instrument; and operate to return to starting point all the selecting instruments
on the line other than the one selected; second-to transmit impulses at the
completion of the phase of the selected instrument to operate the mechanical
device brought into connection with the transmitter by the selected instruinent,
and third-to co-operate with the impulses of opposite character to bring all the
instruments on the line to starting point when the work is done. Upon a suitable
part of the frame-work of the machine are erected the switch contacts m, m',

page_text: m2, m3; m and m 3 are joined together; a spring switch brush M is also suitably
attached so that its free end will contact with the teeth of the wheels. The con-
ducting teeth make contact by sliding upon the free end of this switch brush, the
non-conducting teeth are higher and actuate the switch brush to open one circuit
and close the other; for example: The current enters from binding post 8 to the
conducting wheel whilst a branch is connected to brush m 2, from wheel it passes
to brush M and wire to binding post 10, thence to 11, thence to line, back to
bolt N, brush m, m³, to binding post 9; each of the impulses through this line are
given by the conducting teeth contacting with brush M, when one of the high
non-conducting teeth strikes this brush it opens the first circuit by separating
brushes m and in and contacts the brushes m2 and m3; the current is DOW
from binding post 8 to brush m 2, thence through m3 to binding post 11, thence
through line to binding post 10, thence to brush M, and m³ to biuding post 9, and
out to line.
A modification of the selecting instrument above described may be made
wherein impulses of one polarity are used to turn the selector wheel to the
end of its course and of the other polarity to restore it to zero wherein the
operations are performed by an armature moving in one and the same direction
in response to the impulses of different polarities. "Such an instrument is illustrated
in Figures 10 to 21 inclusive and may be described as follows, looking at said
figures-
Upon a suitable support A is erected the electro-maguet C, and from the base
of the magnet extends an iron frame A', which projects upwardly and furnishes
pivotal points for the wheel or sector as shown at a, and for the armature lever as
shown at 3: d2 is the armaturo lever provided with the usual retractile
spring 64, as the armature is made of iron it will be attracted to the polo of
the electro-magnet by a current of aitber polarity transinitted through its coils, the
pole e 2 of the magnet I prefer to make cone-shaped and form an opening in the
armature lever to conform to the shape of the pole-piece and give a steady and
strong attractive force thereto. Upon the free end of the armature d2 is pivoted
the pawl-hanger c3, which is held normally in position to engage with the ratchets
in the sector by the spring 65. Suitably journalled in appropriate standards are
the shafts of the wheels or sectors FF; they are secured to the shaft and both
move together; they may be cast in one piece, or as shown in Figures 10 and 12
the sector F may be constructed of a piece of suitable material and bolted or
otherwise secured to the sector F; as they move together they also co-operate
with each other in responding to a predetermined arrangement of impulses. The
wheel F has its teeth or notches on its periphery arranged in succession aud
the wheel has a notch here and there and arranged at intervals on its
periphery; theso notches are calculated and arranged with reference to the
wheel to correspond with a predetermined arrangement for cach selecting
instrument. 2 and f3 are the retaining devices constructed in the form
of pivoted spring pawls, they co-act with the sectors and with the
releasing device; 2 with the sector F, and 3 with the sector F; and
both with the pawl-hanger 3: hy this arrangement it will be seen that at the
end of each step of the sectors the retaining pawl f2 dro;s into a notch on the
sector and holds the sector, and that the pawl 3 rides upon the peripheral
surface of the sector F until it drops into one of the notches on that sector.
A suitable spring as h, arranged upon the shaft, returns the wheels or sectors to
starting point; the sectors are impelled in a given direction by the operation of
the armature lever and its pawl and stores up a force in this spring which throws
back the sectors to starting point when the retaining pawls are released from the
wheels. The upper or free ends of these retaining pawls are constructed
differently, the pawl /2 is formed with a projection or extension 4, so that when
the armature lever d2 is attracted to the pole of the magnet, the pawl-hanger c3
will always throw out that pawl. As shown in the drawings the free end of the
pawl 3 is constructed so that the pawl-hanger 3 will also throw it out when

page_text: resting on the plane surface between the notches of its sector but will escape it
when resting in a notch and leave it to hold and retain the wheel or sector in
place, the lug c 4 operates upon the end of retaining pawl 8, and projection c5
co-operates with end of pawl-hanger c 3, to throw out pawl f2. It will thus
be seen that to release the wheels and allow them to be returned to starting point
both pawls must be thrown out. And this operation may be accomplished by
constructing the pawl-hanger c 3, with suitable projections and making the ends of
the retaining pawls alike. Pivoted to a suitable part of the frame is a guiding
device, as shown in the drawings it is constructed in the form of a polarized horse-
shoe magnet N; its free ends are its poles and have a movement limited by
suitable stops, it is attracted in one direction or the other according to the polarity
of the current transmitted through the coils of the electro-magnet C, a lug or
guiding device n¹, is secured to one of the free ends of this magnet which
co-operates with a lug n 2 on the pawl-hanger c 3. During the impulses which are
transmitted to impel the sectors the current is of a polarity which will throw out
the lug from the path of the lug n 2, and allow it to escape; when, however, the
impulses are transmitted of a different polarity either to release the sector of a
selected instrument at the end of its phase movement, or to release the sectors of
all the other selectors not chosen for operation, the free end of the horse-shoe
magnet is attracted in the opposite direction, bringing the guiding lug' in the
path of the lug n 2, and thereby deflect the pawl-hanger 3 from its normal
course; now when the pawl 3 has dropped into one of its notches on the
instrument selected for operation the pawls 3 on all or many of the selecting
instruments, other than the one specially selected, are resting upon one of the
raised surfaces between the notches on wheel F1, and as a consequence both pawls
of those instruments are lifted leaving the wheels freo whilst in the selected one the
lever strikes the pawl f2 and throws it out, leaving 3 to retain it in place.
If necessary a spring may be used to aid the impulse in throwing the lug a' out of
the path of n 2.
The end of pawl-banger c3 may be provided with the projection e 4, c5, the
latter operating upon the extension of the retaining pawl f2 and the former
upon the retaining pawl 3. Impulses of one polarity from the transmitter will
operate the wheel or sector to the end of its course whilst impulses of a different
polarity operate to release the sectors and adjust the guiding device to deflect the
pawl-hanger c3 to actuate the retaining pawls as already described, or the guiding
device may be stationary and the pawl-hanger itself may be actuated by the
impulse as shown in Figure 21. A predetermined arrangement of impulses governs
cach selecting instrument and this predetermined arrangement is made mechanically
upon each instrument by calculation. Let us take the instrument shown in the
drawings for illustration; the predetermined arrangement is shown as 6-3-4,
which means that starting from the normal position of the instrument (Figure 10),
there are first, transmitted six impulses, each of which impel the sector Fone
tooth, when at the end of the sixth, the pawl f3 drops into its first notch on
sector F; during the entire six impulses and until the last one of the Eix has been
transmitted this pawl has been riding upon the raised surface of the wheel and at
any time during its course and before it has dropped into the notch na impulse of
opposite polarity would lift both retaining pawls and restore the instrument to
starting point; the next notch of the sector F is located at a distance of three
notches on the wheel F which represents three impulses, and the next four notches;
now all of the sectors of the instruments not selected for operation are differently
arranged so that when the selected instrument, as illustrated in the drawings, has
been impelled six notches, an impulse of a different polarity is given, theu at three,
theo at four. These opposite polarity impulses will return all of the instruments
on the line not especially selected to starting point, at the end of some one of the
members of the predetermined arrangement. It will also be seen that an impulse
of one polarity followed by an impulse of an opposite polarity will at all times
restore the selectors to starting point.

page_text: Connected with this instrument there are attachments by which a mechanical
device may be operated by the shine impulses which operate the selecting
instrument. Extending from the sector shaft (Figures 14, 15, 16 and 17) is the
arm d7, and to this arm is pivoted the hanger d 3, attached to the hanger is a
lng d 4, the springs d5, d 6, enitably secured at one end to a part of the frame of
the machine have their other or free enda impinging against the sides of the lug d 4,
the action of theeo springs is to keep the hanger in normal position. A mechanical
device to be operated by the selector may be constructed as follows: Suitable
standards II created upon the frame of the machine and provided with apertures
to serve as bearings for the rod i 5, a spiral spring i2 attached at one end to the
rod and abutting the standard l' at the other enil, exerts its tension to keep the
rod i5 in normal position and to return it to normal position after it is forced
forward. Que end of the rod is provided with the notch i8, a spring entch 14,
enters the notch and holds the rod at the end of its stroke; it will be observed
that the free end of the arm d 3 when in normal position points to the counter-
sunk end of the rod i 5, and when the sector moves the arm actuates the rod to
thrust it forward, whilst the socket in the end of the rod keeps it in place.
The Figures 14, 15, 16 and 17 of the drawings also illustrate the action of the
selector and the mechanical device. When both devices are at starting point as
shown in Figure 14, the hanger d3 points direct toward the end of tho rod i 5 and
in this figure the device is shown connected with the blades of a semaphore; when
the mechanical device is forced to the end of its phase it is caught and held by
the catch i4, at this point the selector has finished its own phase and the pawl (3
is raised out of its last notch and resting on the plane surface beyond, the
hangor 3 is ready to descend and throw out both of the pawls to release the
sector; this position is shown in Figure 15; when the wheels are released and
returned to starting point the mechanical device is still held by its catch, this
position of the instruments is shown in Figure 16. At the next operation of the
sector the hanger d3 strikes the catch i4, releases the mechanical device which
now returns to normal position as shown in Figure 17; the selector is then
returned to normal position when both devices assume the position shown in
Figure 14.
A modification of the selecting instrument is shown in the several Figures 18,
19, 20 and 21, wherein the retaining pawls /2 and f3 are constructed with the
extensions/4,5. The pawl-banger e3 which impels the wheels F F is provided
with a pin c6 and when the impulses are given of a polarity to impol the wheels.
this pin readily passes beyond the surface edges of the retaining pawls and allows
the projection 7 to engage with a notch of the selector wheel. A permanent
magnet as N is pivoted as shown at n 4. It has a stroke limited by suitable stops
and may move backward and forward within those limits. It is provided with a
lug n which acts as a guiding device for the extended end of the pawl-hanger e 3.
The upper end of the magnet N has a polarity opposite to that of the magnet C
when the impulses are transmitted to impel the wheels F F, consequently when
these impulses are given, that end of the magnet is attracted towards the pole of
the magnet Cand sweeps over to the left until stopped. At the starting point the
projections/4, 5 of the pawls 2 and 3 are in line with each other and form
the Fame contour, that is to say, when the projection on the pawl /2 has dropped
in a tooth on the wheel F and the projection of the pawl /3 is resting on a raised
surlace between the notches of ita wheel the projections 4, 5 of those pawls,
have the same lines, and as the lug n' has been thrown out of the way the pawl-
hanger e3 descends and impels the wheels F F, whilst the pin e 6 escapes the
projections f4, 15 on the retaining pawls. When, however, the projection f5
drops into one of the notches on its wheel the pawl /2 assumes the position shown
in Figure 19. When an impulse is given of opposite polarity the polarized lever N
Bies over against the stop n3; and the armature lever descends the projection on
the end of the hanger e3 will pass to the other side of the guiding prece n' and
will be guided thereby to throw the hanger to the left, bring the pin e6 in contact

page_text: with the pawl/2 on the instrument especially selected; but as the pawl 3 has
dropped into a notch on the wheel F the pin c6 passes behind it, and the
instrument selected is retained in position whilst other instruments upon the line
are so arranged that when an impulse of opposite polarity is transmitted their
pawls 3 will be found resting upon one of the raised surfaces of their wheels or
sectors and both pawls will be thrown out together (see Figure 20), restoring
them to starting point either at the first or second or third member of the
combination.
I prefer the form of the apparatus first described whose operation is as follows:
When a selecting instrument of any number is required to be operated the
instruments all stand at the starting point. A description of the mode of operation
of the instrument shown in the drawings will describe the operation of any and all
of them. The predetermined arrangement upon that instrument as already stated
is 6-3-4 and the first operation of the device is to send out six impulses of a
given polarity. The retaining pawl f2 drops into a notch with each impulse and
retains the sector in place whilst the armature lever and its pawl-hanger c3 arc
retracted to preparo for another impulse. At the end of the sixth impulse the
pawl 3 drops into its first notch on the ɛector F. All of the other instruments
upon the line not especially selected for the purpose, or many of them, have their.
sectors so arranged that their pawls f3 will drop into a notch on the wheel F¹ at
some other number than 6. An impulse of opposite polarity is now given which
throws the permanent magnet with its lug n', to the opposite limit of its stroko
whereby the projection on the pawl-hanger is deflected from its course so that
upon the instrument especially selected it will strike the projection f4 of the
retaining pawl/2, lift it out of place and leave the pawl f3 to hold the sector
and prevent it from returning to starting point. Upon all the other instruments
on the line which have a different number for the first member of its predetermined
arrangement the pawl-hanger will lift both of the retaining pawls and all of them
will be returned to starting point. The next three impulses of the first polarity
are then given when the pawl f3 drops into its second notch. Au impulse of
opposite polarity is again transmitted which returns to zero most, if not all, of
those instruments on the lino which have not been returned the first time. Then
four impulses of the first polarity are given which operate the sector of the
selecting instrument to the end of its phase, and then an impulse of opposite
polarity is given to return any instrument on the line remaining which has not
been returned at previous impulses. The operation of the selector and the
mechanical device together has already been described.
The machines are all so arranged that an impulse of one polarity followed by
an impulse of another polarity will restore all of the instruments to zero. When,
therefore, a selecting instrument has completed its work it will be restored back
to starting point by an impulse of the first polarity followed by an impulse of
opposite polarity. The machine is very accurate, may be operated wherever
a selecting instrument of any description may be operated, and may be applied
to all the uses and purposes to which the selecting instruments are generally
applied.
One of the features of the apparatus as shown in the figures enables me to
compensate for the saturation of the electro-magnet, that is to say, when an
impulse of given polarity has been transmitted through the coils of the magnet
the core becomes saturated by the impulse, which saturation increases as the
impulses are repeated and generally it takes a perceptible time to dispense with
its influence. Therefore, when the polarized magnet N has been repeatedly
attracted by the magnet C, it would be sluggish in its return to its other stop as it
would be retarded by the residual magnetism in the magnet C. But the instant
an impulse of opposite polarity is given it flies back to its stop, relieves the
magnet Col its residual magnetism which at once assumes a magnetism of
opposite polarity and enables the device to perform accurate and rapid movements
in all its parts.

page_text: When this instrument and a mechanical device are worked together it will be
seen that the same impulses which operate the sector of the selecting instrument
operate the mechanical device to the end of its phase and this phase movement of
the mechanical device may be so arranged that it arrives at the limit of its
movement in one direction at or about the same time that the sector of the
selecting instrument arrives at the end of its phase. It will also be seen that
when the catch has operated upon the mechanical device it holds it in placo,
allowing the sector of the selecting instrument to be returned to its starting point
whilst the mechanical device is still held in position; with a return of the sector
to its normal position, any other selector upon the line may be operated, still
leaving the mechanical device of the first instrument in position.
It will also be seen that when in this position and it is desired to restore the
mechanical device to its own normal position the devices now operate upon the
releasing mechanism of the mechanical device and thereby throw it back to its
original position.
It is possible also with this device to restore all the mechanical devices on the
line at once and without going through the predetermined arrangement of impulses
which governs or controls each of the selectors in series, for example: in the
selector illustrated in the drawings, the predetermined arrangement is 6-3-4, the
aggregate of which is 13. Now beyond the notches on the whoels or sectors
which complete the aggregate number, there is on the sector F', a raised space on
which the pawl f3 rides: if therefore, the aggregate of all the predetermined
arrangements of the selectors on a given line were 13, for example-6-4-3, or
6-5-2, or 6-1-6, or 5-3-5, it is plain that after 14 impelling impulses were
given the pawl 3 would rest on all the sectors upon this raised space and an
Now it might happen
impulse of opposite polarity would send them all to zero.
that, a particular mechanical device should be operated to the cad of its phase
and left there whilst the sector of the instrument were returned to zero, then
another might be operated and another and all of them left and retained in position
by its respective catch; at the end of the day or at any time it may be desired to
bring all of the sectors and all the mechanical devices to starting point, it would only
be necessary to transmit 14 impelling impulses consecutively which would release
all of the mechanical devices, then one impulse of opposite polarity which, would
release all of the sectors when all the dovices would be returned to starting point.
Nor is it necessary to arrange the sectors so that all of them would aggregate the
same number, in one the aggregate might be 10, in another 11, in another 12, and
80 on, in such cuse it would be necessary only to transmit impelling impulsos in
Buccession until their aggregate would be one more than that of the sector on the
line which is arranged to contain the largest number, and then transmit an impulse
of opposite polarity to return all of the mechanical devices aud all of the selectors
to starting point.
Another modification of the saine instrument may be made by sending impulsos
of one polarity through the coils of an electro-magnet to impel the selector to the
end of its course and of the opposite polarity through the coils of another magoet
to restore it to zero. Such an instrument is illustrated in Figures 22, 23 and 24
and may be described as follows:
Upon a suitable base are mounted two electro-magnets C and C', and betweón
the two is placed a vibrating armature B which is suitably pivoted to a part of the
frame. Extending from the top of the armature is the lover or bar d 2 pivotally
connected with a part of the armature and has a reciprocating movement corre
sponding with the vibration of the armature. A post or standard as A' is slotted
at the top and through this slot is passed the end of the lever d2 which gives the
lever a steady reciprocal movement. Pivoted to this lever is a pawl 03 which
oporates the wheel or sector intended to work out the combination of impulses.
Suitably mounted upon a shaft are two wheels F and F', which turn together on
the shaft. One of these wheels has a series of notches into which the pawl o3
drops to operate the wheels or sectors to the end of their course. The other wheel

page_text: or sector has its notches cut with intervening spaces between them and co-operate
with the first wheel in working out the combination of the instrument. Two
retaining pawls as 2 and 3 serve to hold the wheels and check them from returning
backward. These wheels when operated in one direction work against the tension
of a spring and are thrown back to starting point by this spring when the wheels
are released.
It will be seen by the above arrangement that a current through magnet C
will draw the armature B in one direction and when the current is changed
to the magnet C the armature moves in the opposite direction, and so long as
impulses are given with the current through the magnet C the wheels are
impelled by the pawl c3 and are released by chinnging the current to the
magnet C. Each of the selecting instruments is set to a special combination, that
is to say, starting from any point on the wheel F, the wheel F¹ is provided with
notches at intervals and when the pawl f3 drops into one of these notches and an
impulse is given through the magnet C the pin c4 on the lever d2 lifts the pawl
out of the ratchet and passes over the top of 3: the pawl f2 which rests in its
notch holds the wheels and prevents them returning to their starting point ponding
the operation of working out the combination. At the same time all the sectors
upon the different instruments not specially selected to be worked out have their
pawls 2 resting upon a raised surface between the notches and when this occurs
both pawls being in line of engagement are lifted and their wheels are released.
When a combination bae been entirely worked out and the wheels have gone to
the end of their phase movement, a pin f6 upon wheel F' closes the brushes i
and completes circuit leading to binding posts 4 and 5, to make a call, ring a bell,
or perform any other service for which they are intended, and when this operation
is finished the wheels of the selecting instrument thus worked out are restored to
zero by an impulse of a polarity which will raise both pawls. Thus au impulse
of a polarity to impel the wheels followed by one of opposite polarity will find the
pawl 2 resting on one of the raised spaces so that both pawls will be lifted and
the instrument returned to starting point. The standard or bar O is cut out at
the top at o 2 and co-operates with a pin 03 on the pawl c 3 so that when the bar d 2
moves toward the magnet C¹ the pin o 3 slides upon the cut-out portion o 2 and lifts
the pawl c3 to clear the teeth on the wheel.
The current passing through main line M-L, and through the polarized relay-
magnets R, R, as shown in Figure 24, actuates the polarized armature T to one
side or the other according to the polarity of the impulse transmitted. On either
. side of this armature are the contacts S and S' which are connected with the
binding posts 1 and 3 respectively, whilst the binding post 2 is connected with one
side of local battery L, B, and the other side of the battery with the armature T.
It will be seen from this arrangement that when the armature T contacts with S
the current is through magnet C, and when it contacts with S, the current is
through magnet C, then actunting the armature B and the mechanism connected
therewith according to the polarity of the current transmitted. The device may
be connected up in other ways to effect the same result.
A transmitting instrument specially designed and adapted for use in all of the
above described forms of selectors wherein impulses of opposite polarities are used
as described is shown in Figures 25, 26, 27 and 28, and may be described as follows:
The instrument is designed to transmit impulses of opposite polarities and inny
be used with selecting instruments constructed to respond to such impulses or with
any other device wherein such electrical impulses are transmitted.
Upon a suitable base A are erected the standards B in which are journalled the
ends of the shaft C. Upon this shaft are secured a series of disks and a single
disk D. The disk D is provided with teeth around its periphery in succession,
with a cut-out space hereinafter described. A cross-piece d joins the uprights B-B
at the top and is used as a support and slide for the bandle E, which carries a
brush, this handle may be slipped or moved along the cross-piece so that the
brush e' may be made to contact with any one of the disks d.

page_text: Journalled in the frame is the shaft F, which carries on its outer end the
lever G having a projection g', which projection is attached to one end of a
spring 9 2, whose other end is attached to a suitable part of the frame; the action
of this spring is to retract the lever when thrown forward and by means of suitable
gearing turn the shaft C which carries the disks; upon the shaft F, is secured a
toothed segment F1, which meshes with a pinion f2, secured to a cam f3, provided
with a notch f4, and both loosely revolve upon the shaft C when actuated by the
segment ; a touthed wheel is secured to the shaft C, and carries a pivoted
pawl c2, so that when the pinion 2 has been turned by the segment one
revolution this pawl drops again into the notch f4 and the shaft C, carrying the
disks, is ready to be revolved by the action of the spring 92, and makes one
revolution stopping at normal position as shown in Figure 27. This wheel c
meshes with suitable gearing which actuates the fan c3 to steady the movement of
the shaft C and disks when revolving.
The disks d are provided with teeth which are arranged or adjusted to suit the
requirements of the various combinations and as the shaft C revolves those teeth
transmit electrical impulses through the brush to the coil of the magnet H¹.
The disk D is provided with the brush d 2, and as the disk revolves its teeth
transmit electrical impulses to the coil of magnet H, so that the disks d, and the
disk D co-operate with each other and transmit as required the impulses to actuate
the armatures of the magnets H, H', that is to say, an impulse of one polarity
excites magnet H, and of the other polarity magnet H. On the base, which is
made of insulating material, are erected the electro-magnets H, H, having
armatures h, h, provided with conducting extensions 2, h3; upon the same base
is also erected post 4, post h5, post h6; the post 6 is provided with the
cross-piece h7, which serves as a contact and stop for the extensions h 2 and 3
when retracted by the springs h8, h9.
The device is connected up as follows: On the base are shown the binding
posts 1, 2, 3, 4, 5, 6. Connected to binding post 1 is a wire leading to posts h 4, h 5,
and connected with binding post 2 a wire leading to post h6 supporting cross-
piece 7. The wires leading into binding posts 1 and 2 are from the terminals of
A dynamo or generator; connected to binding post 3 is a wire leading to frame of
magnet H, and from binding post 4 a wire leading to frame of magnet H'; the
wires leading into binding screws 3 and 4 are terminals of main line, over which
impulses are transmitted to operate selecting instruments or other devices. A wire
running from binding post 5 is connected with inner ends of coils of magnets H
and H. The outer end of coil of magnet H leads to brush d 2, and the outer end
of coil of magnet H' leads to brush e; wire from binding post 6 is connected via
frame of machine to rotating disks, and the posts 5 and 6 are the terminals of local
battery L-B.
It will be seen that an impulse from the teeth of any one of the disks d through
brush e, energizes maguet H', whose extension makes contact with post h 5, the
current then flows through extension 3, armature h', to binding post 4, then
ria line through selector or other instrument back to binding post 3, then to
armature h, to cross piece h7; post h6, to binding post 2, out to generator, thus
transmitting an impulse of one polarity through the instruments on the line. An
impulse from the teeth of the disk D energizes magnet H, whose armature
extension makes contact with post h 4, and the current runs through said extension
and armature h to binding post 3, thence through instruments on line to binding
post 4, thence via frame to armature h', to cross-piece 7, post h6 to binding
post 2 to generator, thus transmitting an impulse to line of opposite polarity to that
above described.
In order to make different combinations of impulses of opposite polarities to
suit the requirements of the different combinations of the instruments it is only
necessary to adjust or regulate the teeth of each of the disks d with the teeth
on the disk D, the teeth on the latter remaining without change, while the brush e'
may be slipped or moved to contact with any oue of the disks d.

page_text: The operation of the device is as follows:
The operator first selects the combination for a given instrument on the line and
moves the brush e to contact with its corresponding disk; he then throws forward
the lever G until the pawl c2 drops into notch f4 on the cam, then releases the
lever, when the shaft C revolves one revolution, the teeth of the disks D and d
make their contact with their respective brushes and work out the combination
with the instruments on the line.
In operation with a selecting instrument arranged for the purpose, the wheel D
trausmits the impulses which turn the wheels or sectors of these instruments to the
ends of their phases, and the wheels send the impulses which restore them to
zero; when other instrumentalities are connected with the transmitter by the
operation of the selector such as a mechanical device which is to be operated by
impulses of opposite polarity to those which actuate the selector wheels, the
disk D is cut out as shown at D2 to allow the teeth on wheels d to transmit
these impulses.
Having now particularly described and ascertained the nature of iny said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is
1. In an electric selecting instrument a magnet provided with an armature
responding to impulses of opposite polarities, in combination with devices actuated
mechanically by the armature in responding to impulses of one polarity, whereby
the selecting instrument is brought to the end of its phase and devices actuated by
the armature in responding to an impulse or impulses of opposite polarity to those
above referred to whereby all other selecting instruments within the circuit are
restored to starting point without affecting the one selected for operation.
2. In an electric selecting iustrument a magnet provided with an armature
responding to impulses of opposite polarities in combination with devices actuated
mechanically by the armature in responding to impulses of one polarity, whereby
the selecting instrument is brought to the end of its phase and devices actuated by
the armature in responding to an impulse of opposite polarity to those above
referred to whereby the same instrument is restored to starting point.
3. In an electric selecting instrument, a magnet provided with an oscillating
armature responding in direction of its movement according to the polarity of the
impulse transmitted, meaus for completing the phase of a selected instrument,
operated mechanically by the movement of the armature in one direction, and
means for restoring the same instrument to zero operated by the movement of the
armature in the opposite direction.
4. In an electric selecting instrument a magnet provided with an oscillating
armature responding in direction of its movement according to the polarity of the
impulse transmitted, means for completing the phase of a selected instrument
operated mechanically by the movement of the armature in one direction and
means for restoring all other instruments on the line to zero operated by the
movement of the armature in the opposite direction.
5. In an electric selecting instrument, a magnet provided with an armature
responding in direction of its movement according to the polarity of the impulse
transmitted, means for completing the phase of an instrument selected, actuated
mechanically by the movement of the armature in one direction and incaus for
restoring other instruments on the line to starting point at intervals during the
operation of the instrument selected by movement of the armature in the
opposite d rection.
6. In an electric selecting instrument two wheels or sectors adapted to respond
to electrical impulses, one of said. wheels having a series of successive notches
around its periphery and means to Impel the same in response to the impulses one
notch at a time, the other wheel having its notches arranged at intervals and
separated by a raised space between. them, in combination with an impelling bar

page_text: arranged to release both retaining pawls when one of them 18 resting on the raised
space between its notches.
7. The combination with an electrical impulse transmitting instrument adapted
to transmit impulses of opposite polarities, of a series of selecting instruments
each provided with an impelling pawl responding to impulses of one polarity to
complete its phase and of an opposite polarity to restore it to starting point, a
retaining pawl to hold the selector in position when its phase is completed, and be
released by contact with the impelling pawl in responding to the impulses of
opposite polarity.
8. An electric selecting instrument provided with a movable device for
completing its phase in combination with a transmitting instrument arranged to
transmit impulses of opposito polarity, mechanical devices responding to impulses
of one polarity from said transmitter for giving to the phase-completing device a
forward movement, a mechanical device for holding and retaining the phase-
completing device in position, and means operated by the actuating pawl of the
selector in response to an impulse or impulses of opposite polarity for releasing
the phase-completing device at the end of its journey or at intermediate points
whilst completing its phase movement and thereby allowing it to he returned to
normal position.
9. An electrical transmitting instrument adapted to transmit impulses of opposite
polarities and a selecting instrument in circuit therewith adapted to respond to
impulses from said transmitter of one polarity to complete its phase and of an
opposite polarity to restore it to starting point, in combination with other
instrumentalities out of circuit with said transmitter, means actuated by the
selector in responding to its impulses to thereby connect the other instrumentalities
operatively with the transmitter, and devices for operating the other instrumentalities
when connected, actuated by impulses of a polarity opposito to those which
complete the phase of the selector."
10. An electrical transmitting instrument adapted to transmit impulses of
opposite polarities and a selecting instrument in circuit therewith adapted to
respond to impulses from said transmitter of one polarity to complete its phase and
of an opposite polarity to restore it to starting point, in combination with other
instrumentalities out of circuit with said transmitter, means actuated by the
selector in responding to its impulses to thereby connect the other instrumentalities
operatively with the transmitter, devices for operating the other instrumentalities
when connected actuated by impulses of a polarity opposite to those which
complete the phase of the selector, and means for holding the selector and circuit
in position during the operation of the other instrumentalities.
11. A series of selecting instruments adapted to respond to impulses of opposito
polarities, in combination with a transmitting instrument in circuit therewith and
provided with means suitably arranged for transmitting impulses to the selector
of one polarity to thereby complete the phase of one of the selecting instruments,
and means for transmitting impulses of an opposite polarity to thereby return all
the selecting instruments on the line to starting point other than the one selected
for operation.
12. In an electric selecting instrument an electro-magnet provided with an
armature lever and means for transmitting electrical impulses of opposite polarity
through the coils of the magnet, in combination with devices responding to the.
impulses of one polarity to thereby impel the selecting instrument to the end of its
phase, and devices actuated by impulses of opposite polarity to thereby restore all
other instruments on the line to starting point, both operated by the movement of
the armature lever in the same direction.
13. In an electric selecting instrument an electro-magnet provided with an
armature lever and means for transmitting impulses of opposite polarity through
the coila of the magnet, in combination with devices actuated by impulses of one
polarity to impel the solecting instrument to the end of its course, and devices
operated by au impulse or impulses of opposite polarity: for restoring the same to

page_text: normal position at the end of its phase both operated by the movement of the
armature lever in the same direction.
14. In an electric selecting instrument two wheels or sectors adapted to respond
to electrical impulses, one of said wheels having a series of successive notches
around its periphery and means to impel the same in response to the impulses one
notch at a time, the other wheel having its notoles arranged at intervals and
separated by a raised space between them, in combination with a retaining pawl
for each wheel and an impelling pawl arranged to release both retaining pawls
when one of them is resting on the raised space hotween its notches.
15. In an electric selecting instrument adapted to respond to electrical impulses
of different polarities to completo its phase, the combination of impelling devices
actuated by impulses of one polarity and releasing devices actuated by impulses of
the opposite polarity, and a guiding device actuated by the impulses to direct the
actuating devices of the instrument to inspel the wheels or release them according
to the polarity of the impulse.
16. In an electric selecting instrument adapted to respond to electrical impulses
of different polarities to complete its phase, the combination of a pawl-hanger
actuated by impulses of one polarity and thereby impel the selecting instrument,
retaining devices to hold the instrument when impelled and a movable guiding
device actuated by the impulses to direct the pawl to impel the instrument, or
throw out the retaining devices according to the polarity of the impulses.
17. The combination with an electrical impulse transmitting instrument adapted
to transmit impulses of opposite polarities, of a selecting instrument and a
mechanical instrument each having a phase movement and each adapted to
complete its phase in response to the predetermined arrangement of impulses
from said transmitter, and mechanism operated by said impulses to thereby return
the selecting instrument to starting point and leave the mechanical device at rest.
18. The combination with an electrical impulse transmitting instrument, of a
selecting instrument and a nechanical device each having a phase movement and
each responding to the same predetermined arrangement of electrical impulses to
complete its phase, mechanism actuated by said impulses to thereby restore the
selecting instrument to starting point and leave the mechanical device at rest, and
means netunted by a succession of impulses whereby the mechanical devico is
restored to starting point.
19. In an electric selecting instrument adapted to respond to impulses from a
local battery to work out its phase, the combination with two electro magnets in
the local circuit and an armature lever common to both magnets, of a transmitting
instrument adapted to transmit impulses of opposite polarities to thereby direct
the current of the local battery to either magnet according to the polarity of
the impulse transmitted, and means operated mechanically by the armature lever
in respouse to the attraction of one of the magnets to thereby actuate the
selecting instrument to the end of its phase, and means actuated by the same
armature in responding to the attraction of the other magnet to thereby restore the
selecting instrument to starting point.
20. In an electric selecting instrument adapted to respond to impulses from a
local battery to work out its phase, the combination with two electro-magnets in
the local circuit and an armature lever common to both magnets, of a transmitting
instrument adapted to transmit impulses of opposite polarities to thereby direct
the current of the local battery to either magnet according to the polarity of the
impulse transmitted, and means operated mechanically by the armature lever in
response to the attraction of one of the magnets to thereby actuate the selecting
instrument to the end of its phase, and means actuated by the same armature in
responding to the attraction of the other magnet to thereby restore all other
selecting instruments on the line to starting point without affecting the one
selected.
21. In an electric selecting instrument two wheels or sectors, upon one of which
is cut a series of notches in succession and on the other a set of notches separated

page_text: by a raised space between them both working together on a single shaft, and two
retaining pawls one for each wheel, in combination with two electro-magnets and
an armature lever operated thereby, mechanism connecting the armature lever with
the wheels to work out the phase of the instruments, means for transmitting
electrical impulses of different polarities, and means actuated by the impulses for
bringing into circuit one magnet or the other according to the polarity of the
impulse transmitted.
22. In an electric selecting instrument an armature pivoted between two magnets
adapted to respond to impulses of different polarities, in combination with two
wheels or sectors actuated thereby to work out the phase of the instrument or
release the wheels, an arm or bar pivoted to the armature and arranged to
reciprocate therewith, and suitably guided in its movement, and a pawl for actuating
the wheels pivoted to the bar, substantially as described.
23. In an electrical transmitting instrument, a disk-carrying shaft, provided with
means for imparting a rotary movement thereto, in combination with a disk as D
Recured in a fixed position on said shaft and provided with a series of teeth
arranged in succession to co-operate with a suitable conductor and thereby transmit
electrical impulses of one polarity, and a series of disks as d each provided with a
Bet of teeth differently composed or arranged to co-operate with a conductor and
thereby transmit electrical impulses of au opposite polarity to those transmitted
by the disk D, said disks d, adapted to be adjustably arranged on said shaft
whereby each of them may be combined with the teeth on the fixed disk D, to
co-operate therewith and transmit different combinations of electrical impulses of
opposite polarities.
24. In an electrical transmitting instrument, a disk-carrying shaft, provided
with means for imparting a rotary movement thereto, in combination with a disk
as D, secured in a fixed position on said shaft, and provided with a series of teeth
arranged in succession to co-operate with a fixed conducting brush, whereby
electrical impulses of one polarity are transmitted, and a series of disks d each
provided with a set of teeth differently composed, or arranged to co-operate with a
conducting brush adapted to be moved in contact with any one of the disks d, and
thereby transmit electrical impulses of an opposite polarity to those transmitted by
the disk D, said disks d adapted to bo adjustably arranged on said shaft whereby
each of them may be combined with the teeth on the fixed disk D, to co-operate
therewith and transmit different combinations of electrical impulses of opposite
polarities.
25. In an electrical transmitting instrument a disk-carrying shaft provided with
the single disk D provided with teeth arranged in succession and the disks d,
provided with teeth differently composed and arranged in combination with the
fixed conducting brush d2 co-operating with the disk D, whereby impulses of one
polarity are transmitted, the cross piece d' and the sliding brush co-operating
with the disks d, whereby impulses of an opposite polarity to those above referred
to are transmitted.
26. In an electrical transmitting instrument, a disk-carrying shaft provided with
the toothed disk D, provided with teeth arranged in succession and its conducting
brush 2, the toothed disks d, provided with teeth differently composed, and its
conducting brush 6, in combination with the electro-magnets H and H' interposed
in the circuit, the disk D arranged to transmit its impulses through the coils of
magnet Hand the disks d arranged to transmit its impulses through the coils of
magnet H'.
27. In an electrical transmitting instrument, a disk-carrying shaft provided with
the toothed disk D, provided with teeth arranged in succession and its conducting
brush d2, the toothed disks d provided with teeth differently composed and its
conducting brush e, and means for rotating the shaft in combination with the
magnets Hand Haud their armnature h, h, having the extensions h2, h3, and
the contact stop h7, arranged and operating substantially as described.
28. In an electrical transmitting instrument, a disk-carrying shaft provided with

page_text: means for imparting a rotary movement thereto, in combination with a disk as D
secured in fixed position on said shaft, and provided with a series of teeth arranged
in successiou to co-operate with a suitable conducting brush and thereby transmit
electrical impulses of one polarity, and a series of disks as d, each provided with a
Bet of teeth differently composed and arranged to co-operate with a conductor and
thereby transmit electrical impulses of an opposite polarity to those transmitted by
the disk D, and adapted to be adjusted with the teeth on the latter disk and to be
combined therewith to form different combinations and transmit said combinations
in impulses of opposite polarities, in combination with a selecting instrument
adapted to respond to a fixed combination of electrical impulses to work out its
phase by means of the impulses transmitted from the wheel D and be restored to
starting point by means of the impulses transmitted from one of the wheels d.
Dated the 1st day of September 1896.
THEO. MCKENNA,
Applicant.