IMPROVEMENTS IN PRINTING TELEGRAPHS, TRANSMITTERS AND CIRCUITS THEREFOR
Year: 1883

page_text: LETTERS PATENT to Herbert John Allison, of the firm of Allison Brothers,
Patent Agents, Southampton Buildings, London, for an Invention of
"IMPROVEMENTS IN PRINTING TELEGRAPHS, TRANSMITTERS AND CIRCUITS
THEREFOR" communicated to him from abroad by Stephen Dudley Field, of
the City and State of New York, United States of America,
PROVISIONAL SPECIFICATION left by the said Herbert John Allison at the
Office of the Commissioners of Patents on the 23rd October 1883.
HERBERT JOHN ALLISON, of the firm of Allison Brothers, Patent Agents,
Southampton Buildings, London, "IMPROVEMENTS IN PRINTING TELEGRAPHS,
TRANSMITTERS AND CIRCUITS THEREFOR" a communication to me from abroad by
Stephen Dudley Field, of the City and State of New York, United States of
America,
My invention relates generally to that class of printing telegraphs in which two
type wheels are used, whose movement is controlled or regulated by an electro-
magnetic escapement, so that they are rotated and positioned for printing by "step
by step" movement.
It relates more particularly to means for determining in such instruments, which
of the two type wheels shall be printed from; to means for controlling what is now
generally termed the "unison" in printing telegraphs; to means for preventing
any false impression on the record from the wheel not desired to be printed from
and any blurring or disfiguring of the record from accidental contact of the paper
with either wheel; to a transmitter adapted for use therewith and to the arrange
ment of circuits, both those in the instruments and those connecting the transmitting
and printing instruments.
In one form of that part of the invention relating to the determination of which
wheel shall be printed from a platen of sufficient width to take upon one only of
the two type wheels is used.
This platen is mounted in a base capable of reciprocation in a plaåten frame in a
direction at a right angle to the plane of rotation of the type wheels.

page_text: The movement of this platen frame toward the wheels is effected by an arm
taking thereunder and attached to or projecting from the armature lever of the
printing magnet, while its movement away from the wheels is controlled by a
suitable retractor.
The reciprocating platen base is attached to the armature lever of an extra and
neutral electro-magnet in the type wheel circuit, so as to be reciprocated with the
movement of such armature lever.
When then the transmitter controlling pulsations through the type wheel circuit
to position the type wheels, is stopped on a closed circuit, the armature lever places
the platen under one wheel, while when the transmitter is stopped on an open
circuit, the retractile spring of the armature lever places the platen under the other
wheel.
In an instrument provided with these means for determining which wheel shall
be printed from, and in fact, in many two wheel printers, there may be danger of
blurring or disfiguring the record from accidental contact of the paper with either
wheel, or of making a false imprint from improper positioning of the platen or
wheels, or either or both dangers may arise from other causes.
To guard against such dangers what may be termed a guard is mounted, or
fastened, between the two type wheels, projecting slightly beyond their printing
planes in the direction of the approach of the platen, so as normally to prevent the
paper from touching either wheel, unless, as is the case when it is desired to print,
a positive forco be applied to carry it around or beyond the line of the guard.
A suitable device for such a guard is a disk of slightly larger diameter than the
wheels, rigidly mounted on their axis and between them, its edge projecting beyond
their edge and so holding the paper away from them, the blow of a narrow platen,
such as described, bending the paper on the proper side around such disk and
carrying it to the proper wheel to be impressed.
In one form of that part of the invention relating to unison devices I have a
novel combination and arrangement of devices in the transmitter and the receivers,
so that the coujoint action of both is necessary to permit the continuity of action
of both instruments, the unison devices being automatically brought into or out of
action without any care or attention on the part of the operator and without any
cessation of the normal operations of the instruments excepting such as may be
necessitated by failure of unison to bring them to unison.
The means for accomplishing this is more fully hereinafter set forth.
A two wire printer is used, one circuit controlling the type wheel escapement
and mechanism by means of alternating currents, while the other controls the
press or printing mechanism in any well known manner.
A transmitter is used having a rotating arm adapted to be stopped by the
depression of a pin in its path, the arm being attached to the shaft of an anchor
controlling an escapement which operates the current sending device, which may
be arranged to send reversed currents or pulsations of one polarity only.
In the type wheel circuit is placed at the transmitter a magnet having an
armature lever whose free end is formed into a hook or otherwise arranged so as
to be adapted, when the armature lever is not attracted by the magnet, to catch
and stop the lever, arm or finger of the transmitter.
At the receiver another magnet is placed in the same circuit having an armature
lever, whose free end is formed into a hook or otherwise arranged so as to be
adapted to catch and hold a finger or arm projecting from the type wheel shaft or
some member of the type wheel train.
In both these magnets, the magnetic strength and the resilience of the retractors
of the armature levers are so adjusted relatively to each other that the rapid
impulses sent by the transmitter are sufficient to so magnetise the magnets as to
cause them to attract their armatures.
The consequence is that both the armature levers remain away from their
magnets during the ordinary working of the transmitter, and in such position,
catch and hold the arms or levers, both in the transmitter and receiver,

page_text: When however the arm in the transmitter is so caught and held, a prolonged
current is sent over the line, passing through both magnets and causing them to
attract their armatures and release the arms.
It follows then, that in every revolution both must be in unison to be simul-
taneously released and allowed to proceed, that if either has been moving too fust
or too slow one or the other will be held till both are at the same point, when
both are released and allowed to proceed from the same initial point.
A similar effect may be produced by omitting the catch and magnet in the
transmitter, making in lieu thereof one of the teeth in the wheel controlling
the impulse mechanism of such size relatively to the others, that it shall cause the
reverser to send a prolonged current, irrespective of polarity, over the line to the
receiver, giving thereby time for the unison magnet at the receiver to act.
By such an arrangement unison may be automatically secured without increase
of battery, the shunting of resistance or special operation therefor, as has hitherto
been practised.
In another form of that part of the invention relating to unison devices I provide
a unison mechanism for printing telegraphs, adapted to be called into action only
after several revolutions of the type wherl
This I accomplish by placing the unison stop upon a wheel receiving motion
from the type wheel shaft through more or less intermediate gearing, the gearing
being so calculated that the wheel carrying the stop, shall rotate once only while
the type wheel is revolving several times.
In the printing telegraphs noted, polarized magnets may be used, in which case,
as in many forms of telegraphy reversed currents or currents of alternating polarity
must be used. One portion of the invention relates to transmitters adapted to
constantly reverse the currents.
In using such reversed currents it often seems desirable to retain in the circuit
a current of the same polarity as that effecting the operation, in order to maintain
the parts of the receiver in the relation given them by the current of such polarity.
When however a full strength current is used for this latter purpose it is apt to
cause the armature "to stick" or cling to the pole of the magnet, difficulty in again
starting the instrument resulting therefrom.
In other apparatus, some part is maintained in a desired relation by keeping the
circuit charged to a small percentage of its normal working strength, so that a
transmitter is required which shall throw the full strength of the current into the
circuit during its operation, but, upon stoppage, shall cause only a definite
percentage thereof to be left in the circuit.
This latter is notably the case in certain printing telegraphs invented by me and
for which I have heretofore filed proper application for patents, wherein the unison
or some other device is kept out of action by a magnet in a circuit normally
charged to a small percentage of the current required to cause other magnets in the
same circuit to accomplish their work.
In this portion of the invention therefore I furnish a transmitter which while in
action shall reverse or change the polarity of the current thrown upon the line and
shall throw such current upon the line as of the full or maximum strength of tho
battery employed, while when inactive, it shall throw to line a current of only
some definite percentage of the strength thereof and of the polarity determined by
the last moveinent of the transmitter.
To accomplish this, between the main battery and the line, a resistance is placed,
so calculated with reference to the line, as to weaken to a definite degree, the effect
of the current in the line.
The reversing key, controlling this main battery, is provided with contact points,
insulated from the body of the reverser and adapted to close the circuit of a local
battery at either extreme of play of the reverser.
In this last or local circuit, is placed a relay, having an armature whose
retractile force is so adjusted, that, owing to the rapid makes and breaks of its
circuit effected by the movement of the reverser while in operation, the magnet

page_text: does not become sufficiently charged to withdraw the armature from its back
stop.
Through its back stop, this armature controls a shunt circuit around the
resistance mentioned and leading to the main line.
The result theroof is that during the operation of the reversing transmitter, the
resistanco noted is cut out of circuit and the battery is upon the line as of full
strength. When however the reversing transmitter is brought to rest, it closes the
local circuit sufficiently for the magnet therein to break the shunt circuit, where-
upon the battery is still upon the line but through the resistance which weakens
its effect thereon to the desired point.
This carries into effect a substantially new method of operating telegraphic
instruments, viz, positioning the electro-magnetic portions thereof by currents of a
maximum potential and maintaining them so long as desired in such position by a
current of less potential.
In some forms of telegraphy, more especially in what are known as “step by step'
printers, it is desirable to perform two or more different operations over the same wire.
This has been done by sending a comparatively weak current for one operation
and a stronger current for another, or by sending currents of short duration for one
and of longer duration for another operation, the magnets to be effected being
properly adjusted for these variations.
I however use neither of these plans, but taking as a standard a current of any
givon length, sufficient to operate the magnet in the circuit requiring the longest
period of current, to operate another magnet solely, I divide such current into
impulses, any one of which is sufficient to operate the last mentioned magnet but
not the first one.
This part of the invention relates therefore to this novel method, to a transmitter
by which at will may be transmitted what may be called semi-impulses, that is
the whole impulses being divided into two semi-impulses and to the arrangement
of magnets for utilizing such different characters of impulses over the wire.
I use primarily any well known form of reversing key properly connected to a
battery and also to the line through the devices hereinafter described.
For use with printing telegraphs the type may be of the well known reversing
key, that is a key actuated by a motive power and escapement.
Instead however of one pair of springs as is usual, I use two.
Of these, the first pair is connected, one to either pole of a battery, whose centre
is connected to the ground, while the key itself is connected to the line as
hereinafter explained.
The second pair is arranged so that cach contacts with a common anvil, forming
electrical connection between them and arranged so that one is lifted from such
common anvil just after the key has made contact with one of the springs referred
to and to return to such anvil just before the key and spring break contact.
The key lever however is connected primarily to the line through one of this
second pair of springs, their common anvil, and the second spring of this pair. In
such construction, the koy when in operation always lifts one of the second pair of
springs from the common anvil, breaking the electrical connection between them,
just after it has formed electrical connection from the battery to lino through
contacting with one of the first pair of springs.
The result of this is that each impulse is cut in two, this is immediately after
contact is made between the key lever and one of the first pair of springs, the
circuit is broken at one of the second pair of springs, sending a short impulse,
while as the key returns this break at the second pair is closed and immediately
thereafter the circuit is broken at the first pair, the currents sent being graphically
represented by --, two dots, instead of, a dash.
The two springs of the second pair however are also electrically connected by a
second circuit, which is a shunt to the circuit through their common auvil; this
shunt circuit contains a key, whose lever and back stop are normally in the circuit
and maintain it closed,

page_text: The result of this is that so long as the key is unused, a circuit direct from the
reversing key to line is maintained without regard to the operation of the reversing
key lever upon the second pair of springs referred to, so that during such period,
currents of maximum length of duration are sent to line.
If however this key be operated, this second or shunt circuit is broken and tho
only path to line for each impulse is through the two pair of springs, whereupon
each impulse is broken or, as it were, chopped in two.
To utilize this principle in a receiving instrument, I use a step by step printing
telegraph, of one or more type wheels, actuated by any suitable motor and
controlled by an escapement and polarized magnot. In the same circuit is
arranged the unison magnet, the strength of which and the resilience of whose
armature lever retractor are so adjusted relatively to each other, that the total
impulse is necessary to give the magnet the strength requisite to hold its armature
and the unison out of action, while when the semi-impulses are sent, the magnet
cannot overcome the resilience of the spring and the unison mechanism is permitted
to act.
Of course these particular actions are only typical, as any other two actions may
be accomplished over the same wire upon the same principle.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Herbert John Allison in the Patent Office on the 23rd April
1884.
HERBERT JOHN ALLISON, of the firm of Allison Brothers, Patent Agents,
Southampton Buildings, London, "IMPROVEMENTS IN PRINTING TELEGRAPHS,
TRANSMITTERS AND CIRCUITS THEREFOR" a communication to me from abroad by
Stephen Dudley Field, of the City and State of New York, United States of
America,
My invention relates generally to that class of printing telegraphs in which two
type wheels are used, whose movement is controlled or regulated by an electro-
magnetic escapement, so that they are rotated and positioned for printing from
step to step."
It relates more particularly to means for determining in such instruments, which
of the two typo wheels shall be printed from; to means for controlling what
is now generally termed the "unison" in printing telegraphs; to means for
preventing any false impression on the record from the wheel not desired to bo
printed from and any blurring or disfiguring of the record from accidental contact
of the paper with either wheel, and to a transmitter adapted for use therewith and
to the arrangements of circuits, both those in the instruments and those connecting
the transmitting and printing instruments.
In one form of that part of the invention relating to the determination of which
wheel shall be printed from a platen of sufficient width to take upon one only
of the two type wheels is used.
This platen is mounted on a baso capable of reciprocation in a platen frume
in a direction at a right angle to the plane of rotation of the type wheels.
The movement of this platen frame toward the wheels is effected by an arm
taking thereunder and attached to or projecting from the armature lever of the
printing magnet, while its movement away from the wheel is controlled by a
suitable retractor.
The reciprocating platen base is attached to the armature lever of an extra and
neutral electro-magnet in the type wheel circuit, so as to be reciprocated with the
movement of such armature lever.
When then the transmitter controlling pulsations through the type wheel circuit
to position the type wheel is stopped on a closed circuit, the armaturo lever places
the platen under one wheel, while when the transmitter is stopped on an open
circuit, the retractile spring of the armature lever places the platen under the
other wheel.
In an instrument provided with these means for determining which wheel shall
be printed from, and in fact, in many two wheel printers, there may be danger of
blurring or disfiguring the record from accidental contact of the paper with either
wheel, or of making a false imprint from improper positioning of the platen or
wheels, or either or both dangers may arise from other causes.
To guard against such dangers what may be termed a guard is mounted, or
fastened, between the two type wheels, projecting slightly beyond their printing
planes in the direction of the approach of the platen, so as normally to prevent
the paper from touching either wheel, unless, as is the case when it is desired to
print, a positive force be applied to carry it around or beyond the line of the
guard. A suitable device for such guard is a disk of slightly larger diameter than
the wheels, rigidly mounted on their axis and between them, its edge projecting
beyond their edge and so holding the paper away from them, the blow of a narrow

page_text: platen, such as described, bending the paper on the proper side around such disk
and carrying it to the proper wheel to be impressed.
This is illustrated in Figures 1 and 2 of the drawings in which Figure 1 is a
perspective view of so much of a printing telegraph as is necessary to show this
part of the invention, while Figure 2 is a front detail view showing the relations
of the wheels and guard.
P. M. is a polarized magnet, whose armature ends in or is formed as a yoke Y,
taking in escapement wheel C mounted on shaft D, these devices forming an
electro-magnetic escapement controlling the action of the motor (not shown), which
motor connects. to shaft D by pinion E
Upon D are mounted, and rotate therewith, the two type wheels 1, 2, ench
provided on its periphery with appropriate letters, figures, or symbols. G is the
printing magnet in a circuit 4. 4. und has the armature H attached to armature
lever I journalled at b, b.
Upon or by the lever I, an arm F is carried, to which a retractor, of com-
paratively low resistance, say 10 or 15 per cent of the printing strength of G,
tending, when H is not attracted by G, to put F in the path of a pin a on the
wheel G, forming therewith a unison device.
Another arm c, taking underneath the platen frame k, k, and adapted to lift it
when His attracted, is carried by the lever I.
The spring or retractor therefor, B, is adjusted to a comparatively high power,
say 80 per cent of the printing strength of G.
The circuit 4, 4, is kept normally charged to a degree sufficient to enable G to
overcome the stress of A, thereby keeping the unison devices inactive, they being
operated then upon an entire break in the circuit.
To print, the entiro current or rather. a full strength current is thrown through
4, 4, when G, becoming fully charged, will attract H, overcoming the stress of B
and causing the platen frame to be lifted.
In this platen frame h, k, is mounted the platen bed P, so as to have a recipro-
cating motion therein, a platen P' of about the width of a type wheel being
mounted thereon.
The reciprocation of this platen bed is controlled by the armature lever m of the
magnet M in the circuit 3, 3.
If the type wheels be positioned and the circuit 3 kept closed, m will be
attracted by M and will pull the platen bed so as to place P' in position to print
from 1, while if they be positioned while 3 is kept open, the spring g will cause m
to position P¹ for printing from 2.
Upon the shaft D, and between the wheels 1, 2 is mounted the guard disk N
of slightly larger diameter than the wheels, or arranged in any suitable manner
to project beyond the plane of their peripheries in the direction of the approach
of the platen P¹ thereto.
This guard disk normally keeps the paper 0 (see Figure 2) away from either
wheel. When the act of printing takes place, the platen P' bends the paper O,
or forces it by the guard disk to the proper wheel, while the guard disk holds it
positively and clearly away from the other wheel.
In one form of that portion of the invention relating to unison devices I have
a novel combination and arrangement of devices in the transmitter and the
receiver, so that the conjoint action of both is necessary to permit the continuity
of action of both class of instruments, the unison devices being automatically
brought into or out of action without any care or attention on the part of the
operator and without any cessation of the normal operations of the instruments
excepting such as may be necessitated by failure of unison to bring them to
inison.
The means of accomplishing this is moro fully hereinafter set forth and claimed.
A two wire printer is used; one circuit controlling the type wheel escapement
nd mechanism by means of alternating currents, while the other controls the
ress or printing mechanism in any well known manner.

page_text: In the type wheel circuit is placed at the transmitter a magnet having an
armature lever whose free end is formed into a hook or otherwise arranged so as
to be adapted, when the armature lever is not attracted by the magnet, to catch
and stop the lever, arm or finger of the transmitter.
At the receiver another magnet is placed in the same circuit having an armaturo 5
lever, whose free end is formed into a hook or otherwise arranged so as to be
adapted to catch and hold a finger or arm projecting from the type wheel shaft or
some member of the type wheel train.
In both these magnets, the magnetic strength and the resilience of the retractors
of the armature levers are so adjusted relatively to each other that the impulses 1
sent during the rapid reversals of current by the transmitter are insufficient to so
magnetize the magnets as to cause them to attract their armatures. The consequenco
is that both the armatures' lovers remain away from their magnets during the
ordinary working of the transmitter, and in such position, catch and hold the arms
.or levers, both in the transmitter and receiver,
When however the arm in the transmitter is so caught and held, a prolonged
current is sent over the line passing through both magnets and causing them to
attract their armatures and release the arms or levers. It follows then, that in
every revolution both must be in unison to be simultaneously released and allowed
to proceed, that if either has been moving too fast or too slow, one or the other
will be held till both are at the same point, when both are released and allowed to
proceed from the same initial point.
A similar effect may be produced by omitting the catch and magnet in the
transmitter, making in lieu thereof the proper tooth in the wheel controlling the
reverser of such size relatively to the others that it shall send a prolonged current,
irrespective of polarity, over the line to the receiver, giving thereby time for the
unison magnet at the receiver to act.
By such an arrangement unison may be automatically secured without increase
of battery, the shunting of resistance or special operation therefor, as has hitherto
been practised.
Suitable arrangements for carrying this part of the invention into effect are
shown in Figure 3 of the drawings, wherein is represented, mainly diagrammatically,
the transmitting and receiving stations and instruments. Tv at the left being the
transmitting station, and Rv at the right the receiving station, connected by a
line 4 of any desired length. It is to be understood that any number of receiving
stations Rv may be connected in the circuit or lino 4.
The transmitter is primarily of the ordinary construction, having an escape
wheel B driven by any suitable prime motor, not here shown, and actuating the
.anchor A and thereby controlling the springs R, R, and their contact with a
common anvil R', so as to connect the battery M. B. to line and ground alternately
+ and
as clearly shown in the drawings. Attached to the shaft of B is tho
finger or arm C arranged to be stopped by the depression of any of the koys D in
the well known manner.
-
In the line circuit 4 is placed the electro-magnet E having an armature lever F
provided with the usual retractor and contact stops. The end of the lever F is so
placed or is so fashioned into a hook, and the whole is so arranged that the arm or
finger C shall be caught by a when the armature lever is held from the magnet by
the spring 8.
The receiving instrument Rv is conventionally represented by the polarized
magnet E actuating the armature and escapement e controlling the movement of
the escape wheel on the shaft of the type wheel d, the printing and inking
mechanism, paper feed, framing and other details not necessary to the showing of
the invention being omitted.
In the line circuit 4 at the receiver is placed the magnet I having an armature
lever provided with the usual stops and retractor. The end of the lover his so
placed or is so formed into the hook i arranged to catch and hold an arm or finger g
projecting from the type wheel shaft or from some member of the type wheel train
1

page_text: and thereby stop the rotation thereof when the lever h is held away from the
magnet by the spring 8¹.
The magnetic force of G and I and the retractile force of their springs 8, 8¹ are
so adjusted relatively, that the short or ordinary impulses of alternating polarity
thrown through them when the transmitter is working normally, are not sufficient
to charge them to the degree necessary to attract their armatures. The armature
levers therefore normally stand away from their magnets as shown and in position
to stop both transmitter and receiver once during every revolution. As C is
rotated by the motor of the transmitter it proceeds uninterruptedly until it reaches a
when it is stopped; this stoppage causes a prolongation of the current or impulse
last transmitted until E is sufficiently charged to overcome the stress of 8, attracting
the armature and releasing C.
This same prolongation has a similar effect on I, causing it to attract h and
releaso g.
By these means a perfect unison between the transmitter and all receivers in
circuit is automatically secured without care or attention on the part of the
operator and without stoppage of the instrument for its normal work, excepting
the slight stoppage of C, which generally is so momentary as practically not to be
observable.
The same effect could be produced by omitting E and f, the proper tooth in the
escapement wheel B being made of such size proportionately to the others as to.
cause a suitably prolonged contact between A and the proper spring R, to be made,
and by such means, send once during every revolution, such an impulse as will
suffice to take the unison mechanism at Rout of action.
The magnet G shown is a relay for controlling the second or printing circuit 5,
it being controlled by a local battery L. B. and local circuit 6, one terminal of
which is connected to the arm or lever C and the other to the koys D. D. so that
it is completed on contact of C and any D on the depression of the latter to stop C.
In another form of that part of the invention relating to unison devices I provide
a unison mechanism for printing telegraphs, adapted to be called into action only
after several revolutions of the type wheel.
This I accomplish by placing the unison stop upon a wheel receiving motion
from the type wheel shaft through more or less intermediate gearing, the gearing
being so calculated that the wheel carrying the stop shall rotate once only while
the type wheel is revolving several times.
This is illustrated in Figure 4 of the drawings in which M. M. A. B. constitute
the ordinary polarized escapement of a printing telegraph, whose type wheel or one
of whose type wheels is designated by the dotted circle C mounted on the type
wheel shaft D.
Upon the type wheel shaft is mounted a pinion E meshing into a suitably
supported gear wheel F carrying the unison stop a. As here shown the pinion
has 10 teeth and the gear wheel 40, hence the latter would make one revolution
to four of the type wheel. This relation however may be varied so as to cause
one revolution of the gear to any desired number of the type wheel, or a greater
number or train of gearing may be interposed between the type wheel shaft and
the unison stop.
M is the unison magnet placed in the printing circuit 2, 2, (1, 1 being the
escapement circuit). M³ is an independent neutral magnet controlling the unison
only, the printing or press magnets not being shown.
The armature lever N of M¹ plays at its rear end between adjustable stop
screws n, n, and is provided with the usual retractor S.
At its other end it is formed into the hook b adapted to catch and hold the
unison stop a, when the parts are in the proper relative position and thereby stop
the revolution of the type wheel until a and b are freed by the attraction of Ñ
by M'.
M' may be operated in either one of several ways, a constant weak current may

page_text: be maintained in 2, 2, causing M' to normally hold N, unison being effected by a
completo break in the circuit; or 2, 2, may be normally uncharged, permitting
the unison to go into operation whenever the fixed number of revolutions have
been made.
In the printing telegraphs noted, polarized magnets may be used, in which case,
as in many forms of telegraphy reversed currents or currents of alternating polarity
must be used. One portion of the invention relates to transmitters adapted to
constantly reverse the current.
In using such reversed currents it often seems desirable to use a current of the
samo polarity as that effecting the operation, in order to maintain the parts of the
receiver in the relation given them by the current of such polarity.
The object of this part of the invention therefore is to furnish a transmitter
which while in action shall reverse or change the polarity of the current thrown
upon the line and shall throw such current upon the line as of the full or maximum
strength of the battery employed, while when inactive, it shall throw to line a
current of only some definite percentage of the strength thereof and of the polarity
determined by the last movement of the transmitter.
To accomplish this, between the main battery and the line a resistance is placed,
so calculated with reference to the line as to weaken to a definite degree, the effect
of the current in the line.
The reversing key, controlling the main battery, is provided with contact points,
insulated from the body of the reverser and adapted to close the circuit of a local
battery at either extreme of play of the reverser.
In this last or local circuit is placed a relay, having an armaturo whose retractile
force is so adjusted that owing to the rapid makes and breaks of its circuit effected
by the movement of the reverser while in operation, the magnet does not become
sufficiently charged to withdraw the armature from its back stop.
Through its back stop, this armature controls a shunt circuit around the resistance
mentioned and leading to the main line. The result thereof is that during the
operation of the reversing transmitter, the resistance noted is cut out of circuit and
the battery is upon the line as of full strength. When however the reversing
transmitter is brought to rest, it closes the local circuit sufficiently for the magnet
therein to break the shunt circuit, whereupon the battery is still upon the line,
but through the resistance, which weakens its effect thereon to the desired point.
This carries into effect a substantially new method of operating telegraphic
instruments, vis., positioning the electro-magnetic portions thereof by currents of a
maximum potential and maintaining them so long as desired in such position by a
current of less potential.
In Figure 5 of the drawings, is represented, mainly diagrammatically and
conventionally, a reverser, suitable connections and associated parts for carrying
my invention into effect.
D represents an ordinary lever key pivoted at e, provided at one end with the
button or finger piece E and at the other end with the contacts d, ' in electrical
connection with its body. This key is used to operate the reverser R and here is
only typical of any suitable form of manually or mechanically operated key adapted
to work a reverser.
The reverser R consists of the springs A, B, one connected to the Z, the other to
the C end of a main or line or other battery M B, whose circuit is to be reversed.
These springs are provided with contacts, as at a, b, adjusted to both contact
with d, d, when the key is in a neutral or non-operative position, and with
contacts a, b, adjusted to not contact with the double anvil c, c, when the key is
in that position.
These contacts are also so adjusted, that as the key is moved, say to left A, a
and d will remain in contact, a¹ and e' be further separated and 6' and e' come into
contact as or just before b and d' are separated.
The double anvil is connected to the line by wire 1 and the key D to the ground

page_text: by wire 4. As thus far described, the operation of the parts, as may be seen, is that
of a simple reverser.
Between the double anvil c, c', and the line however is placed a resistance r,
which may be an ordinary adjustable resistance, and calculated ordinarily so that
when in the circuit it shall weaken tho effective force of MB upon the line and in
the instruments to be operated, to the desired per cent.
From the point however a shunt around R is provided via 2, the armature
lever H of a magnet G, its back stop and 3 to the line. This magnet G is in a local
circuit 5, 5 having a local battery L. B. and controlled by contacts f, fƒ³, on the free
end of the key D.
Upon the free end of the key but insulated therefrom is fastened the piece F,
formed, as here shown, with two right angles, and carrying the contacts f, f', which
contact with anvils g, h, in the local circuit 5, 5.
The form of F is not material so long as the contacts f, f', are so arranged
thereon that contact with g shall be made at the end of movement of the key in
one direction, while contact with h is made at the end of movement of the key in
the other direction.
The retractile force of the spring S of the armature lever H and the magnetic
force of G are so adjusted that G does not become sufficiently powerful to attract H
from its back stop, during the rapid makes and breaks at g, h, incident to mani-
pulation of the key, but that a slight pause on either contact is necessary therefor.
It follows then that during the operation of the reverser, say for setting a
distant type wheel or positioning any other apparatus, the path of the current is
via 1, 2, i, H, 3 to line, shunting the resistance, but when the reverser is stopped,
upon the setting or positioning, the local circuit 5 is closed long enough at either'g
or h for G to become charged sufficiently to attract H, breaking the shunt circuit,
wherefore the path of the current is via 1 and R to line, R weakening its practical
effect on the distant apparatus to the desired extent.
By such means I am enabled to effect the proper positioning of distant
apparatus by a current of say maximum strength and to retain it in such position
so long as necessary by a weakened current or maintain for other purposes n
normally weak charge upon a line during the non-operation of the transmitter.
In some forms of telegraphy, more especially in what are known as "step by
step" printers, it is desirable to perform two or more different operations over the
same wire.
This has been done by sending a comparatively weak current for one operation
and a stronger current for another, or by sending currents of short duration for
one and of longer duration for another operation, the magnets to be affected being
properly adjusted for these variations.
In my present invention however I use neither of these plans, but taking as à
standard a current of any given length, sufficient to operate the magnet in the
circuit requiring the longest current, to operate another magnet solely, I divide
such current into impulses any one of which is sufficient to operate the last
mentioned magnet but not the first one.
This part of the invention relates therefore to this novel method, to a transmitter
by which at will may be transmitted what may be called the whole impulses or
what may be called semi-impulses, that is the whole impulse being divided into
two semi-impulses and to the arrangement of magnets for utilizing such different
characters of impulses over one wire.
I use primarily what may be termed semi-impulses; to means whereby at will,
either such whole impulses or semi-impulses inay be transmitted over the line an
arrangement of magnets for utilizing such different characters of impulses over one
wire.
In carrying my invention into effect I use primarily any well known form of
reversing key properly connected to a battery, and also to the line through the
devices hereinafter described.

page_text: For use with printing telegraphs the type may be of the well known reversing
key, that is a key actuated by a motive power and escapement.
Instead however of one pair of springs as is usual I use two.
Of these, the first pair is connected, one to either pole of a battery, whose centre
is connected to the ground, while the key itself is connected to the line as
hereinafter explained.
The second pair is arranged so that each contacts with a common anvil, forming
electrical connection between them and arranged so that one is lifted from such
common anvil just after the key has mado contact with one of the springs referred
to and to return to such anvil just before the key and spring break contact.
The key lover however is connected primarily to the line through one of this
second pair of springs, their common anvil and the second spring of this pair.
In such construction, tho key when in operation always lifts one of the second
pair of springs from the common anvil, breaking the electrical connection between
them, just after it has formed electrical connection from the battery to line through
contacting with one of the first pair of springs.
The result of this is that each impulse is cut in two, that is immediately after
contact is made between the key lever and one of the first pair of springs, the
circuit is broken at one of the second pair of springs, sending a short impulse,
while as the key returns this break at the second pair is closed and immediately
thereafter the circuit is broken at the first pair, the currents sent being graphically
represented by --, two dots, instead of -, a dash.
The two springs of the second pair however are also electrically connected by a
second circuit, which is a shunt to the circuit through their common anvil, this
shunt circuit contain. a key, whose lever and back stop are normally in the
circuit and maintain it closed.
'
The result of this is that so long as the key is unused, a circuit direct from the
reversing key to line is maintained without regard to the operation of the reversing
key lever upon the second pair of springs referred to, so that during such period
currents of maximum length of duration are sent to line.
If however this key be operated, this second or shunt circuit is broken and the
only path to line for each impulso is through the two pairs of springs, whereupon
each impulse is broken, or as it were, chopped in two.
To utilize this principle in a recoiving instrument, I use a step by step printing
telegraph, of one or more type wheels, actuated by any suitable motor and
controlled by an escapement and polarized magnet. In the same circuit is arranged
the unison magnet, tho strength of which and the resilience of whose armature
lever retractor are so adjusted relatively to each other, that the total impulse is
necessary to give the magnet the strength requisite to hold its armature and the
unison out of action, while when the semi-impulses are sent, the magnet cannot
overcome the resilience of the spring and the unison mechanism is permitted to act.
Of course these particular actions are only typical, as any other two actions may
be accomplished over the same wire upon the same principle.
These things are conventionally illustrated in the drawing, in which Figure 6
shows, mainly in diagram, a transmitter and a receiver embodying my invention;
wbile
Figures 7 and 8 are graphic representations of the whole and semi-impulses sent
by the transmitter.
In Figure 6 T is the transmitter. In it the arm A¹ is on a shaft driven by proper
motive power, to which shaft is secured the escape wheel A, actuating the anchor B,
pivoted at b, and terminating in the key lever B¹, which carries contacts i, i,
arranged to take on the contacts o, c', of the first pair of springs E, E, and form
therewith a reverser for the battery V, which is here shown as a divided battery
having a ground connection 6 from its centre while its C and Z ends are connected
to E and E¹ respectively.
Upon the free or further end of B¹ are arranged, one on each side, the insulated
1

page_text: pieces c, c, arranged to take under the second pair of springs 0, 0¹, and lift one or
the other thereof, according to the direction of movement of B', from the anvil D,
common to and electrically connecting both of them.
From the lever B₁ an electrical connection is made to one of this second pair of
springs, in this case O, while from it to the other spring, here O¹, an electrical
connection is formed through a key R and its back stop r.
The lever B and its contacts and the springs E. E'. O. O¹. are so adjusted
that B¹ immediately after contacting with E or E shall lift the spring O or O¹, the
one on the corresponding side from the anvil D and thereby break the connection
between them and between B' and the line through the anvil D.
So long however as the key R is in the position shown there is a circuit around
D via 2, 3, R, 4 to line so that the pulsation is of full length or a whole impulse,
which may be graphically illustrated as in Figure 8, where P. N. represent these
whole impulses.
If however at any time the key R be depressed, breaking this shunt 3, R, 4
around D, immediately after circuit be closed at e or el it will be broken at D during
the advance movement of B¹, on the return movement of B' it will be made again
at D just before being broken at e or e¹ and P or N of Figure 8 will be divided
into semi-impulses as p, p¹, n, n', in Figure 7.
In the receiver R is illustrated a device for making use of these two characters
of current, an escapement and unison device being chosen as types. P. M representa
the polarized magnet actuating the armature and escapement R controlling the
escape wheel T upon a shaft upon which a type wheel W, indicated in dotted lines,
is mounted.
Upon the type wheel shaft is an arm m, adapted to take into and catch upon a
hook at the free end of an armature lever h, when such lever is held by the
resilience of the spring s against the action of the unison magnet U. M. in the
escapement circuit 5, 5.
The spring & and the magnetic strength of U. M are so adjusted relatively to each
other that it requires what has been called herein before, a whole impulse to charge
U. M sufficiently to attract h and thereby keep the unison mechanism m, h', out of
operation.
The result of this is that so long as the key R at the transmitting station is not
used, whole impulses are sent and U. M attracts h, keeping h¹ and m from acting
upon each other.
If however R be used, the shunt around D is broken and semi-impulses are sent,
that is each reversed current is in two impulses, the first of which affects R; the
second simply holding R in the position given it by the first, and neither of which
is sufficient to cause U. M to hold h, whereupon the spring a places h in position to
check the type wheel train and type wheel at the designated or unison point from
which it is released by simply allowing R to resume its normal position.
By thus changing an impulse from its total character or a whole impulse to a
series of semi or fractional impulses, in contradistinction to reversing a current, to
augmenting it or to polarizing it, I am able, without interference with or stoppage
of the transmitter, to accomplish two independent operations over one line.
Having thus described my invention, what I claim and desire to secure by
Letters Patent is :-
1. In a printing telegraph having two type wheels, the combination of the two
type wheels, a platen adapted to print from one only thereof at a time and a magnet
in the type wheel circuit for positioning the platen at will to print from either one
of the wheels substantially set forth.
2. In a two wheol printing telegraph, the combination of the two type wheels,
a reciprocating platen adapted to print from one only of the wheels at a time and
a magnet in the type wheel circuit for controlling the position of the platen
substantially as set forth.
3. The combination, in a two wheel printing telegraph, with the two type wheele

page_text: and the platen for causing an impression therefrom, of a guard substantially as
described, adapted to normally keep the fillet or band of paper away from the type
wheels substantially as set forth.
4. The combination in a two wheel printing telegraph, with the two type wheels
and the platen for causing an impression therefrom, of a guard disk mounted
between the type wheels and rotating with them substantially as set forth.
5. In a printing telegraph line the combination of a receiver having a unison
controlled by a prolonged current and a transmitter provided with means for
automatically transmitting such prolonged current at definite intervals, substantially
as set forth.
6. In a printing telegraph the combination with the type wheel and its motive
power, of a unison mechanism actuated by a magnet in the type wheel circuit and
controlled by prolongation of current, substantially as set forth.
7. In a printing telegraph line, the combination with a transmitter and a receiver,
of magnets at each in the type wheel circuit adapted to be operated by prolongation
of current and mechanism controlled thereby and forming a unison mechanism
automatically controlled by the transmitter, substantially as set forth.
8. The combination with a printing telegraph of a unison mechanism auto-
matically controlled by the transmitter controlling the type wheel escapement,
substantially as set forth.
9. In a printing telegraph the combination with the unison mechanism and type
wheel shaft of an interposed train of gearing for giving the unison stop a less rate
of rotation than the type wheel or wheels, substantially as set forth.
10. In a printing telegraph the combination of a type wheel or type wheels,
an independent unison magnet, a unison stop and a train of gearing, the unison
mechanisn being removed from the type wheel mechanism but acting thereon
through the train of gearing, substantially as set forth.
11. The improved method of operating a telegraph line herein described consisting
in throwing upon the line a current of maximum strength during the operation of
the transmitter and weakening the current during the non-operation of the trans-
mitter, substantially as set forth.
12. The combination with a line, a main battery, and a key or transmitter, of a
resistance between the key or transmitter and line, and a shunt circuit around the
resistance controlled by the key, arranged so as to close the shunt circuit when the
key or transmitter is in operation, and to open it when the key or transmitter is at
rest, substantially as set forth.
13. The combination of a main battery, a key or transmitter, a resistance between
the key or transmitter and the line, a shunt circuit around the resistance, a magnet
and local circuit controlling the shunt circuit and controlled by the key or trans-
mitter, substantially as set forth,
14. The method of accomplishing two operations over one line wire consisting in
transmitting a full length pulsation or impulse for one operation and dividing it
into semi or fractional impulses for the second or other operation, substantially
as set forth.
15. In a transmitter the combination of a pair of springs connected one to each
end of a battery, a key lever, a second pair of springs and an anvil adapted to
normally connect them and a shunt circuit to the anvil controlled by a key,
substantially as set forth.
16. The combination with a current reverser of a second pair of springs normally
electrically connected and adapted to be separated by the key lever and an inde
pendent electrical connection controllable at will to send two different characters
of electrical impulses upon the line, substantially as set forth.
17. In a telegraph transmitter the combination of a current reverser, a second
pair of springs, one of which is connected to the key lever of the transmitter and
the other to the line, a common anvil normally electrically connecting them and an
independent controllable connection between them, substantially as set forth.

page_text: 18. The combination in one circuit of a transmitter adapted to throw into circuit
whole or semi pulsations as described and a receiver having two magnets in such
circuit, one adapted to operate with either character of pulsations and the other
only with full pulsations or whole impulses; substantially as set forth.
In witness whereof, I, the said Herbert John Allison, have hereunto set my hand
and seal, this twenty-third day of April, in the year of our Lord one thousand
eight hundred and eighty-four.
HERBERT, J. ALLISON. (LS.)