IMPROVEMENTS IN PRINTING TELEGRAPHS
Year: 1883

page_text: "
LETTERS PATENT to Herbert John Allison, of 41 Southampton Buildings,
Holborn, in the County of Middlesex, Patent Agent, for an Invention of
"IMPROVEMENTS IN PRINTING TELEGRAPHS 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 20th February 1883.
"
HERBERT JOHN ALLISON, of 41 Southampton Buildings, Holborn, in the
County of Middlesex, Patent Agent, "IMPROVEMENTS IN PRINTING TELEGRAPHS,'
a communication to me from abroad by Stephen Dudley Field, of the City and
State of New York, United States of America.
This invention relates to that class of printing telegraphs in which a tendency is
given by a motive power to the type-wheel or wheels to constantly rotate, and a
magnetic escapement is provided, controlled by currents sent from the transmitting
station, so the tendency to continuous rotation is changed into a " step by step
motion.
"
While some features of the invention may be used with such printing telegraphs
having only one type-wheel, the invention is more particularly intended for
printing telegraphs having two type-wheels, each provided with different sets of
characters, and relates more particularly to the means whereby at will either one of
such two type-wheels may be printed from, and whereby what is known technically
as the "unison" between a printing telegraph or series thereof and the transmitter
may be maintained, the object being to enable the sender at the transmitting end
to change the printing easily, certainly and rapidly from one wheel to the other
and to be able at all times to know that all the type-wheels controlled start from a
certain point and move in unison with the transmitter.
To accomplish these objects the invention embraces several forms or modifications.
In one form the receiving instrument is provided with two type-wheels carried
by independent shafts. One wheel may conveniently carry the letters and the

page_text: other the numerals; and each is provided with a blank or unison point, which may
represent either a space or a dot.
Through the agency of suitable driving mechanisms a tendency is given to both
wheels to revolve continuously in the same direction. The intermittent advance
movements of the type-wheels are controlled, first, by an escapement mechanism
common to both, which acts simultaneously upon each under the influence of
intermittent pulsations of current traversing a conductor preferably devoted to this
purpose alone; and, secondly, said advance movements are independently governed
by the action of an arresting mechanism, the object of which is to hold one of the
wheels at its blank or unison point during the periods in which the other wheel is
in operation.
This arresting mechanism is operated by the same current which actuates the
impression producing mechanism or press, but while the press is actuated to
produce an impression by currents of either polarity, the character of the action of
the arresting mechanism depends upon the direction or polarity of the current.
Thus a copper current may be used to arrest the letter-wheel and a zinc current to
arrest the figure-wheel, while either current will serve to actuate the impression
producing mechanism.
When either wheel has once been arrested, it retains its position of arrest (that
is with its blank space presented to the receiving strip of paper), so long as there
is no change in the polarity of the printing currents.
The other type-wheel, being free to advance under the action of the intermittent
current may be proceeded with independently, and any number of successive
impressions may be taken therefrom so long as the polarity of the printing current
is not changed.
When it is desired to print from the other wheel, the operator at the transmitting
station will first bring the wheel which has been in use to the unison or blank
point, and will there arrest it by reversing the current. The same action not only
liberates the other wheel, but liberates it in unison with the transmitting device so
that it may proceed independently in the manner described.
It will be noticed that in this form there is no special unison device, but that
unison is secured by the operation of the stop and as an incidental function
thereof.
If, however it be desired to add thereto a special unison device, it may be done
in either of the following ways, which are also applicable to many if not all other
means than those described for controlling the type-wheels, selecting the one to be
printed from and printing.
In one form the active pole of the printing magnet is prolonged or enlarged,
so as to furnish upon its side preferably, a surface which shall act upon an extra
or subsidiary armature which is attached to a lever whose other end is adapted
to take in the path of a projection attached to some moving part of the type-
wheel train, and hence, when in action, always stop the type-wheel at that
predetermined point.
In one instance the end of such a lever is normally in the path of a stop on the
type-wheel or a member of its train but is withdrawn therefrom whenever the
printing magnet is actuated. Then when it is desired to certainly bring all
type-wheels into unison, the transmitter is operated to cause at least a full rotation
of the type-wheels, which brings the stop against the end of the lever, which is
then released therefrom by actuating the printing magnet, leaving all the wheels
ready to move from the predetermined point.
In a modification of such form, mechanical devices, the same in principle are
used, but the printing circuit is kept normally charged, say to ten or twenty
per cent of the strength requisite to work the printing magnet, the spring or
retractile force of the unison lever mentioned being correspondingly adjusted. In
such case the printing will be effected by an increase of current upon the printing
circuit and the unison thrown into operation by an entire and complete break
therein.

page_text: In another form, a separate and independent magnet, placed in the printing
circuit, is used to control the unison devices. In such case the printing magnet
may be kept normally charged and the printing done upon the breakage of the
circuit, the resilience of a spring being used to bring the platen to the type-wheel.
The armature lever of the unison magnet in the same circuit is kept normally
away from a stop upon the type-wheel or in its train. A shunt circuit to this
unison magnet is provided, the terminals of which are in the armature and stops of
the polarized magnet controlling the escapement of the type-wheel. Consequently
as the type-wheel is rotated, the contacts in this shunt succeed each other with
such rapidity and are hence so brief that the shunt is not operative, but whenever
the type-wheel circuit is held so as to stop the operation of its escapement, the
shunt becomes operative and the unison magnet allows the unison lever to operate.
By these means the printer may be kept at unison without any special unison
device, or be provided with a unison device operated from the printing magnet either
when it is charged or when it is discharged, or be operated by a special magnet.
The printing from either wheel, that is the selection at will of which wheel is to
be printed from may be controlled by the transmitter in other ways than that
hereinbefore recited.
For instance the two type-wheels may be mounted upon one shaft and controlled
by one escapement, the characters on one wheel being set opposite to the blanks on
the other wheel. Upon the type-wheel shaft is secured a disc having a cogged
edge, the recesses being opposite the letters or characters on one wheel, while the
lands are opposite those on the other wheel.
Attached to the printing lever is the platen, pivoted at its centre and between
the two type-wheels, a spring at one end normally tilting it in one position so it
will take only upon one type-wheel. From the other end projects a pin, adapted
to strike in the recesses or upon the lands of the disc noted, according to the
position of the disc, so that when it is desired to print from one wheel the pin
passing into the recesses, allows the spring to keep the platen tilted so as to print
therefrom. When it is desired to print from the other the pin strikes upon a
land and tilts the platen in the opposite direction against the spring and prints
from the second wheel.
In another form the type-wheels are secured to one shaft and have one
escapement.
The printing is effected by an inked tape interposed between the fillet or band
of paper and the type-wheel.
This inked tape is preferably made of the width of a type-wheel and as an
endless band, and passes through guiders which are carried by the armature lever
of a polarized magnet which places the tape under one or the other wheel according
to the polarity of the current transmitted, so that only one wheel is printed from.
The transmitters used have not been alluded to herein, as they form no part of
the invention herein intended to be secured.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Herbert John Allison in the Great Seal Patent Office on the
9th August 1883.
"
HERBERT JOHN ALLISON, of 41 Southampton Buildings, Holborn, in the
County of Middlesex, Patent Agent, "IMPROVEMENTS IN PRINTING TELEGRAPHS
a communication to me from abroad by Stephen Dudley Field, of the City and
State of New York, United States of America,
The invention in this case relates to that class of printing telegraphs in which
a tendency is given by a motive power to the type-wheel or wheels to constantly
rotate and a magnetic escapement is provided, controlled by currents sent from the
transmitting station, so the tendency to continuous rotation is changed into a " step
by step" motion.
While some features of the invention may be used with such printing telegraphs
having only one type-wheel, the invention is more particularly intended for printing
telegraphs having two type-wheels, each provided with different sets of characters,
_ and relates more particularly to the means whereby at will either one of such two
type-wheels may be printed from and whereby what is known technically as the
"unison" between a printing telegraph or series thereof and the transmitter may
be maintained, the object being to enable the sender at the transmitting end to
change the printing easily, certainly and rapidly from one wheel to the other and
to be able at all times to know that all the type-wheels controlled start from a
certain point and move in unison with the transmitter.
To accomplish these objects the invention embraces several forms or modi-
fications hereinafter described and illustrated in the accompanying drawings.
In one form the receiving instrument is provided with two type-wheels carried
by independent shafts. One wheel may conveniently carry the letters and the
other the numerals; and each is provided with a blank or unison point, which
may represent either a space or à dot. Through the agency of suitable driving
mechanisms a tendency is given to both wheels to rotate continuously in the same
direction. The intermittent advance movements of the type-wheels are controlled,
first, by an escapement mechanism common to both which acts simultaneously
upon each under the influence of intermittent pulsations of current traversing a
conductor preferably devoted to this purpose alone and secondly, said advance
movements are independently governed by the action of an arresting mechanism,
the object of which is to hold one of the wheels at its blank or unison point,
during the periods in which the other wheel is in operation. This arresting
mechanism is operated by the same current which actuates the impression
producing mechanism, or press, but while the press is actuated to produce an
impression by currents of either polarity, the character of the action of the
arresting mechanism depends upon the direction or polarity of the current. Thus
a copper current may be used to arrest the letter-wheel and a ziuc current to arrest
the figure-wheel, while either current will serve to actuate the impression producing
mechanism.
When either wheel has once been arrested, it retains its position of arrest (that
is with its blank space presented to the receiving strip of paper) so long as there
is no change in the polarity of the printing currents. The other type-wheel, being
free to advance under the action of the intermittent current may be proceeded with
independently, and any number of successive impressions may be taken therefrom
so long as the polarity of the printing current is not changed.
When it is desired to print from either wheel the operator at the transmitting
station will first bring the wheel which has been in use to the unison point, and

page_text: will there arrest it by reversing the current. The same action not only liberates
the other wheel, but liberates it in unison with the transmitting device so that it
may proceed independently in the manner described.
This may be better understood by reference to Figures 1 and 2 of the drawings,
in which two type-wheels are shown at A' and A'; the former may conveniently
carry the letters, and the latter the numerals, punctuation points and other
miscellaneous characters, as desired, this being a matter of discretion.
Both are provided with blank or unison spaces. Each type-wheel is carried
upon a separate shaft as seen at B' and B2, and both shafts are driven by the
weight C acting through suitable intermediate mechanism. Both type-wheels
advance step by step in the same direction. The shafts further respectively carry
escapement wheels D' and D³, each provided with a like number of teeth engaging
with the pallets upon the anchors E1 and E2, carried by the rock shaft F, which is
arbored at points F1 and F2, and is provided with an armature F³ intervening
between the confronting poles of the polarized magnet G.
The latter is included in the circuit of the line conductor 1, 1, which conveys
impulses alternately positive and negative, established thereupon by any suitable
transmitting device.
The independent circuit of conductors 2, 2, includes the operating magnets of
two distinct mechanisms, namely, the printing press mechanism operated by tho
electro-magnet M', and the unison mechanism for detaining the type-wheels upon
their blank spaces when out of use, operated by the polarized magnet K.
The printing mechanism is shown at H. It is actuated by an electro-magnet H'
with a neutral armature H' included in the circuit 2, 2, and responding to currents
of either polarity.
The armature H2 carries a platen H³ over which passes a band or tape of
paper H. The mechanism for feeding the paper may be of any suitable character
and may be actuated in any well known manner, as for example by the retrograde
movement of the printing lever or armature H³.
With every impulse therefore of sufficient intensity, whether positive or
negative, that traverses the circuit 2, 2, an impression will be taken of the
character or figure immediately above the platen at that particular instant.
If, as is normally the case, the blank point of one of the wheels is above the
platen, an impression will be taken from the other wheel only.
The device for arresting and detaining the particular type-wheel which is
not in use is also operated by the current traversing the circuit 2, 2, already
referred to.
It consists of an electro-magnet K, between the poles of which a polarized
armature K, carried by an armature lever K², fulcrumed at K³, plays between the
stops A3 and A under the action of currents of alternating polarity in a well
known manner.
The type-wheels A' A' are respectively provided upon their confronting faces
with projecting stops A³ A*.
The armature-lever K2 is extended beyond its fulcrum K³ passing between the
type-wheels A and A' as shown in the Figure. When the magnet K is excited
by positive currents the polarized armature K¹ will be attracted toward one of the
pole pieces, and the extension K will be moved into the path of one of the stops
as for example the stop A³ of the wheel A¹. A current in the opposite direction
will cause said extension to release the wheel A' and move into the path of the
stop A of the wheel A*.
Inasmuch as this action is practically instantaneous, it will be understood that
one or other of the type-wheels A' A' is at all times in a state of arrest, by the
action of the extension piece K³.
The other type-wheel is at the same time set free to revolve and printing
may be effected with it accordingly. The stops A3 and Aare placed in such
positions upon the faces of the wheels A' and A', as to determine the arrest of

page_text: each wheel in a position with its blank or unison point presented to the press
mechanism.
The functions of the transmitting apparatus designed to be employed in
connection with the receiving, apparatus herein described, are, first, to establish
upon the line 1, 1, the requisite alternating pulsations for causing the step by step
advance movement of the particular type-wheel which is in operation; second; to
establish the printing currents upon the line 2, 2, when the type-wheel in use has
reached the position in which the required character is presented for printing;
said printing current being of polarity such as not to actuate the arresting or
unison mechanism, and third, the transmitter should be provided with devices
whereby the transmitting operator may change the polarity of the current.
To accomplish these results any of the well known electrical appliances
heretofore employed for such purposes may be made use of, but as such appliances
do not constitute the subject matter of this invention a detailed description of them
is omitted.
The operation of passing from one wheel to the other is as follows:-Assuming
that the type-wheel A' has been in use, the type-wheel A³ meantime remaining at
rest and that it is now desired to print from the wheel A³, the operator by properly
manipulating his transmitting mechanism causes the wheel A¹ to advance to its
blank or unison point. He then reverses the current which operates the unison
mechanism, thus liberating the wheel A* and arresting the wheel A'. The
-wheel A having been previously stopped upon its blank or unison point starts in
unison with the transmitting mechanism and thereafter moves in obedience
thereto.
It is evident that the principle herein set forth, of using two wheels and holding
either in position while the other is in operation, may be applied to a system in
which only a single conductor is employed, by using comparatively feeble currents
to operate the magnet G and more powerful currents of alternating polarities to
actuate the magnets H and K.
In this form of my invention it will be noticed that the two type-wheels are on
separate shafts, controlled however by one escapement and motor and the selection
or determination of the wheel to be printed from depends upon the use of the
device for locking the other wheel in such position that it cannot be printed from.
In other forms of the invention however both wheels are mounted on one shaft
and the printing from either wheel determined by the position of the press or
platen or of an inked tape carried against one or the other wheel by the press or
platen.
In one of such forms the two type-wheels are mounted upon one shaft and
controlled by one escapement, the characters on one wheel being set opposite to the
blanks on the other wheel.
Upon the type-wheel shaft is secured a disk having a cogged edge, the recesses
being opposite the letters or characters on one wheel, while the lands are opposite
those on the other wheel.
Attached to the printing lever is the platen pivoted at its centre and between
the two type-wheels, a spring, at one end normally tilting it in one position so it
will take only upon one type-wheel. From the other end projects a pin, adapted
to strike in the recesses or upon the lands of the disk noted, according to the
position of the disk, so that when it is desired to print from one wheel the pin
passing into the recesses allows the spring to keep the platen tilted so as to print
therefrom. When it is desired to print from the other the pin strikes upon a land
and tilts the platen in the opposite direction against the spring and prints from the
second wheel.
This mode is illustrated in Figures 3, 4 and 5 of the drawings, in which
Figures 3 and 4 are front and side views respectively of a printing telegraph
apparatus embodying this form of the invention and Fig. 5 is a plan of a detail,
the cogged wheel, as described hereinafter.
In these drawings A is an electro or a polarized magnet or one member thereof

page_text: having an armature B attached to the outer end of anchor C, controlling escapement:
wheel D mounted on shaft E, which receives motion through pinion F from any:
suitable motive power. .
As this motive power, its train, the escapement and the framing of the machine,
constitute no part of this invention, further illustration and description thereof are*
not necessary herein.
:
Upon E are rigidly mounted the two. type-wheels G, H for convenience one being'
the letter and the other the figure wheel.
The characters on the two alternate with each other, that is the characters on
one are opposite the blank spaces or intervals between characters upon the other."
In practice however these blank spaces or intervals may be small or of ordinary
size so as not to enlarge such wheel.
It is evident then that upon stoppage of the wheels at any point, but one will
be in position to print squarely from, but if the characters are close together and
an ordinary platen striking on both were used, a partial impression from the other
might and in many cases would be had, which often would lead to confusion.
To avoid this the platen is arranged to strike upon only one wheel, the one.
desired and in position to be printed from.
Upon the shaft E is mounted a cogged wheel I, whose lands i, i, are in line with
the characters on one wheel, whilst its recesses a, a, are in line with those on the
other wheel.
J is the printing magnet in its own circuit and operating on an armature attached
to the printing or press lever K pivoted at k and furnished with usual spring or
retractile device v.
:
Pivoted in bearings b, b, upon this lever K is mounted the tilting platen •L;
having printing surfaces e, e¹, one under each wheel but preferably at a slight angle
to each other that each may present a parallel surface to its wheel and compensate
for the angle of L to the wheels due to its tilting.
From L projectas beneath the wheel I, a pin or arm d while at the other end
of L is arranged a spring c to cause it normally to take upon the type-wheel
nearest to I.
As I rotates with the wheels, and its lands coincide with the characters on one,
while its recesses correspond with the characters on the other, it follows that upon
stoppage of the type-wheels, the arm or pin d will take either upon a land or in &
recess according to which wheel is stopped in position for printing. In the drawing
the recesses of I correspond with the characters on G consequently, if the type-
wheel mechanism be stopped in position for G to be printed from and the press
lever be actuated, the pin or arm d will enter a recess a, allowing the spring c to
tilt the platen, so that the surface or pad e strikes the paper against the wheel G
which then receives an impression therefrom.
"
If however the type-wheel mechanism is stopped in position for the other wheel or
H to be printed from, a landi of the cogged wheel I is in such position that d strikes
thereon and tilts the platen L against the stress of the spring, bringing e' against
the wheel.
In this way either type-wheel may be printed from at will and without change
of current.
It has been attempted hitherto to determine which wheel should be printed
from by a tilting platen, but its tilting or positioning was controlled by an extra
and polarized magnet in the printing circuit, the action of whose armature (con-
nected to the tilting device) was controlled by the polarity of the current in the
printing circuit.
Such an arrangement may be termed a magnetic one, and it necessitated largely
increased resistance in the printing circuit, increased consumption of battery therein
and loss of time.
In this form of the invention however there is used for this purpose the devices
just herein before described and which may be termed purely "mechanical means
in contradistinction to the "magnetic means" noted, that is the positioning of

page_text: tilting of the platen is effected without any extra magnet and by the relation and
joint operation of certain simple mechanical devices added to the type-wheel shaft
and to the platen itself.
In another form or modification the type-wheels are, as in the last case, secured
to one shaft and have one escapement.
The printing is effected by an inked tape interposed between the fillet or band
of paper and the type-wheel.
This inked tape is preferably made of the width of a type-wheel and as an
endless band and passes through guides which are carried by the armature lever
of a polarized magnet which places the tape under one or the other wheel
according to the polarity of the current transmitted, so that only one wheel is
printed from.
This form or mode is clearly illustrated in Figures 6 and 7 of the drawings,
which are side and front views respectively of apparatus embodying this part of
the invention; and in which AA are the magnets between whose poles vibrates
the armature lever B whose other extremity is formed into an escapement C, taking
into an escape wheel D, mounted on shaft E and either imparting a step by step
motion thereto or regulating and controlling a tendency to continuous motion given
thereto by an independent motive power.
Mounted on shaft E are the two type-wheels F, G, one of which, for convenience,
may carry letters and the other figures. In the drawings, the characters on the
two wheels are shown as alternating with each other, but this is not necessary, as
they may alternate or coincide as thought most desirable.
The magnets A, A, or equivalent are in the type-wheel circuit 2, 2, controlled by
any of the well known form of transmittera at the sending station.
H is the printing or press magnet having an armature lever I carrying a platen a,
adapted to strike against both wheels, when the armature attached to I is attracted
by the poles of H.
A retractile device is used to normally throw I away from H consisting of a
bent spring J, having a projection b upon which I strikes.
The advantage of this form is that as soon as 6 is struck and J compressed, the
reaction therefrom tends to throw I off, preventing it from "sticking" and making
quick sharp blow of a upon the type-wheel.
In the printing circuit 1, 1, containing H is placed a polarized magnet L, L',
whose armature lever M pivoted at c is fashioned substantially as shown or in an
equivalent manner and carries the rollers f, g, which form ways or part of a
carriage over which passes the inked tape N, preferably formed as an endless belt,
the other supports or rollers, therefor, which may be stationary, not being shown.
One of the rollers in the path of N may be connected to or actuated from I as
the ordinary and well known paper feeds in this class of apparatus are, so as to
move N after each impression.
The tape N is about the width of the face of one of the type-wheels so that only
one can be printed from at once and it passes between the wheels and the fillet of
paper P.
It follows then that as M is vibrated or rocked it carries the inked tape
underneath one or the other only of the two wheels.
-
If then the polarized magnet be so wound that L' will attract M when a
current is sent over the circuit 1, 1, and L when a current is sent, if a
+ current be sent the tape will be carried under F and it printed from, the
polarized magnet acting practically instantaneously while the printing magnet H
throws I into action immediately thereafter. By these means the polarity of the
current transmitted for printing determines which wheel shall be printed from, the
tape being thereby placed in position to make an imprint from the desired wheel
on the fillet P.
It is evident that an inking roller could be substituted with this shifting
mechanism for the inked tape shown, but I have found the inked tape preferable
in such an organization, in that it does not leave sufficient ink on the wheels for a

page_text: second printing or for blurring, which might cause confusion and uncertainty in
the record.
It will be noticed that no special form of what are now technically known as
"unison" devices is shown in connection with the form illustrated in Figs. 1 and 2,
but that "unison" therein is secured by the operation of the device for locking one
wheel and freeing the other, as an incidental function thereof.
Any known unison may however be added thereto, if desired as a special unison
device.
There are however shown with the other forms hereinbefore described, novel,
simple and reliable means for insuring unison, applicable not only to the forms
they are shown with, but to most if not all of the known forms of step by step
printers.
In several forms of unison the active pole of the printing magnet is prolonged
or enlarged so as to furnish upon its side preferably, a surface which shall act upon
an extra or subsidiary armature which is attached to a lever whose other end is
adapted to take in the path of a projection attached to some moving part of the
type-wheel train and hence, when in position therefor always stop the type-wheel
at that predetermined point.
In one of the instances using such construction, a spring tending when unopposed
to place the end of the lever in the path of the arm or stop and thereby stop the
wheels but the printing circuit is kept normally charged, say to ten or twenty per
cent of the strength requisite to work the printing magnet, the spring or retractile
force of the unison lever mentioned being so adjusted that while this percentage of
current is on the lever will be held from capability of contact with the arm or stop,
against the stress of the spring.
In such case the printing will be effected by an increase of current upon the
printing circuit and the unison thrown into operation by an entire and complete
break therein.
This is illustrated in Fig. 4, wherein an arm or stop M is shown attached to the
type-wheel shaft, to the type-wheel or to some part of the type-wheel train.
The active pole or poles x of the press or printing magnet J, are elongated so as
to afford an active surface upon its or their sides for an auxiliary armature o,
attached to a bent or elbow lever O, to which is connected by any suitable
connection, say the rod P, a pivoted lever N, having a spring or other resilient
device n tending to place the free end of its lever in the path of the arm or
stop M.
•
Normally the printing circuit passing through and around J is kept charged
with a fraction of the current necessary to magnetize J sufficiently to attract K,
say ten to twenty per cent thereof. The printing then is done by throwing into
such circuit an increased or full current. The spring is so adjusted however
that the magnetism in a due to the fraction of current through J is sufficient to
overcome the retractile force of n and hold o attracted to x, so that in operation, N
is normally held away from the position in which it can contact with M. When
then it is desired to use the unison, the printing circuit is completely broken and
the type-wheel circuit used sufficiently to produce at least one full revolution of
the wheels, which are then all stopped at the same predetermined point and
released, to advance for work, by throwing into the printing circuit the percentage
of current necessary to so magnetize x as to attract o.
In another form of the use of such auxiliary armature lever and extended or
prolonged pole of the printing magnet, the end of such lever is normally in the
path of a stop on the type-wheel or a member of its train but is withdrawn there-
from whenever the printing magnet is actuated. Then when it is desired to
certainly bring all type-wheels into unison, the transmitter is operated to cause at.
least a full rotation of the type-wheel, which brings the stop against the end of the
lever, which is then released therefrom by actuating the printing magnet, leaving,
all the wheels ready to move from the predetermined point.
This is shown in Fig. 7, in which is a bell crank lever K, pivoted at c, and having

page_text: at one end an armature i controlled by the extension h of the pole of H, while the
other end is formed into a hook n adapted to contact with a stop d on one of the.
type-wheels or on some member of the type-wheel train.
This unison, of course, tends to stop the wheels always at one point, and by the
attraction of i to h, they are unlocked and permitted to proceed.
It is evident that, as in the former instance, the printing circuit 1, 1, may be
kept normally charged to a percentage of the current required for the complete
operation of H, and the unison kept permanently out of action, by the attraction
of i to h, the unison being then thrown into operation upon a complete break of
the circuit 1, 1.
In such case, this percentage of current would be sufficient to hold M to one of
the poles of L, L', depending on the polarity of the current. In changing from one
to the other polarity under such conditions, K would be momentarily released, but
as it would be immediately attracted, this momentary release would not interfere
with the reliability of the unison.
In another method of effecting this unison a separate and independent magnet
placed in the printing circuit is used to control the unison devices. In such case
the printing magnet may be kept normally charged and the printing done upon
the breakage of the circuit, the resilience of a spring being used to bring the platen
to the type-wheel.
The armature lever of the unison magnet in the same circuit is kept normally
away from a stop upon the type-wheel or in its train. A shunt circuit to this
unison magnet is provided, the terminals of which are in the armature and stops
of the polarized magnet controlling the escapement of the type-wheel. Consequently
as the type-wheel rotated, the contacts in this shunt succeed each other with
such rapidity and are hence so brief that the shunt is not operative, but whenever
the type-wheel circuit is held so as to stop the operation of its escapement, the
shunt becomes operative and the unison magnet allows the unison lever to operate.
This method is clearly shown in Fig. 8 in which A, A, are the escapement
magnets, between which plays the escapement lever B, carrying anchor C,
controlling escape wheel D on the shaft S of the type-wheel E indicated in dotted
lines. 1, 1, in full lines is the escapement or type-wheel circuit.
His the printing magnet in a circuit 2, 21, shown in heavy dotted lines and
kept normally charged, so as to hold its armature lever G, carrying platen F away
from the type-wheel, and against the resilience of a spring or other retractor b.
In this circuit 2, 2, is the unison magnet I having armature lever K pivoted at e
and provided with an adjustable retractor d. The non-armature end of this lever
is arranged to take, when d is allowed to act upon it, in the path of an arm or
stop c which may be called the unison stop, fixed upon the type-wheel shaft, as
here shown, or upon the type-wheel or upon some member of the type-wheel
train.
The force of d and the distance to which the armature may move away from I
are so adjusted relatively to the force of I, that whenever K is released from I, I
has not magnetic force enough to, unaided, again bring K. back.
Upon the printing lever G is mounted an arm g taking under K so as to throw
the stop end of K upwards whenever G is raised to print.
The free end of the escapement lever B plays between contact points i, i, from
which a wire 3 leads to a point x in the circuit 2, while from the lever a wire 4
leads to a point y in the same circuit, the contact points, escapement lever and
wires 3, 4, forming a shunt to I, shown in light dotted lines
The operation of these devices is as follows:-The circuit 2, 2, is kept normally
charged, so that G and K are attracted and held from action by their respective
magnets.
While the escapement C, D is in operation to set the type-wheel or wheels, the
contacts between B and i, i, are so brief that the shunt 3, 4, does not affect I.
If however the escapement be stopped, B rests in contact with one of the points i

page_text: and I becomes demagnetized, allowing spring & to pull the outer end of K down in
position to contact with c.
If now it be desired to use the unison, the escapement B is vibrated by
pulsations in the circuit 1, 1, sufficiently to bring c and the end of K. together, the
force of I being, as before stated, insufficient to attract K to itself again.
The printing circuit is now broken, releasing G, whose spring 6 immediately
throws it up, its arm g throwing the free end of K up and forcing its armature
within effective range of I.
Whenever the escapement is stopped to permit printing and the printing is about
to be effected, the unison lever K tends to come into action, first, because of the
formation of the shunt 3, 4, and second, because the complete break in circuit 2, 2,
to cause the printing. The act of printing however, through the medium of the
arm g, prevents this, restores K to its normal position and the unison is brought into
action only on a complete breakage in the printing circuit.
In most of the Figures it will be noted that many details necessary to a complete
printing telegraph, such for instance as inking rollers or founts, paper reels, paper
feeds, the side framings or supports etc, are omitted. This has been done because
such details formed no part of my invention, their construction and their use with
what is shown, is well understood and known, and their omission rendered clearer
the showing of the matters of invention.
Having thus described my invention, what I claim and desire to secure by Letters
Patent is
First. The combination, substantially as hereinbefore set forth, of two independent
escape-wheels revolving in parallel planes, oscillating pallets for controlling the
intermittent advance movements of each of said escape-wheels; an electro magnet
for simultaneously imparting a like oscillatory movement to the pallets of both of
said escape-wheels; mechanism substantially such as described for arresting the
advance movement of either one of said wheels and simultaneously liberating
the other, and an independent electro-magnet for controlling the last named
mechanism.
Second. The combination, substantially as hereinbefore set forth, of two inde-
pendently moving type-wheels, step by step escapement mechanism whereby a like
intermittent advance movement is imparted to each of said type-wheels, an electro-
magnet in one line wire for controlling said escapement mechanism, mechanism for
locking one or the other of said type-wheels against the action of said escapement
mechanism, and an electro-magnet in a second line wire for determining the action
of said locking mechanism upon one or the other of said type-wheels.
Third. The combination, substantially as herein before set forth, of two inde-
pendently moving type-wheels, step by step escapement mechanism whereby a like
intermittent advanco movement is imparted to each of said type-wheels, an electro-
magnet in one line wire for controlling said escapement mechanism, mechanism for
locking one or the other of said type-wheels against the action of the escapement,
an electro-magnet in a second line wire for determining the action of said locking
mechanism upon one or the other of said type-wheels, an impression platen common
to both type-wheels, and an electro-magnet included in the circuit of the second
line wire for actuating said platen.
Fourth. The combination, substantially as herein before set forth, of two inde-
pendently moving type-wheels, step by step escapement mechanism whereby a like
intermittent advance movement is imparted to each of said type-wheels, and an
electro-magnet in one line wire for actuating said escapement mechanism, mechanism
for locking one or the other of said type-wheels against the action of said escape-
ment, a polarized armature actuated by an electro-magnet in a second line wire
for determining the action of the locking mechanism upon one or the other of said
type-wheels, an impression platen common to both said type-wheels and a neutral
armature actuated by an electro-magnet included in the circuit of the second line
wire, for actuating said platen.

page_text: Fifth. The combination, substantially as herein before set forth, of two inde-
pendently movable type-wheels, an escapement mechanism common to both sid
type-wheels for controlling their intermittent advance movement,.. in'echanism
actuated by currents of a determinate polarity to hold one of said type-wheels in
position to present its blank or zero point to the platen, while permitting the other
type-wheel to proceed, and by currents of an opposite polarity to release the type-
wheel first arrested and lock the other type-wheel in the manner described.
Sixth. The combination, substantially as hereinbefore set forth, of two inde
pendently movable type-wheels, mechanism normally tending to advance said
type-wheels in the same direction, escapement mechanism common to both type-
wheels for controlling said advance movement in accordance with successive electric
impulses from a transmitter, a platen or printing mechanism capable of taking
'impressions from either type-wheel, and a polarized armature actuated by currents
of a determinate polarity to arrest one of said type-wheels at its zero point and
liberate the other to the action of the escapement, or by currents of reverse or
opposite polarity to perform a reverse action."
-
Seventh. The combination, substantially as herein before set forth, of the lever
extension of a polarized armature, two independently movable type-wheels between
the confronting faces of which said extension projects, nechanism whereby said
wheels are advanced in the same direction, and stops upon said wheels for engaging
with said projection respectively, according as said armature is actuated by currents
of one or other polarity.
Eighth. In a printing telegraph, the combination of two type-wheels rigidly
mounted upon one shaft, a printing magnet, an armature lever therefor carrying a
tilting platen and means substantially such as described for tilting the platen to
take upon one or the other of the two wheels, substantially as set forth.
Ninth. In a printing telegraph the combination of two type-wheels and a cogged
wheel, all mounted rigidly upon one shaft, a printing lever carrying a tilting platen,
a lever provided with a piu or arm for taking into a recess or upon a land of the
cogged wheel for determining the position of the platen to print, substantially as
set forth.
Tenth. In a printing telegraph a printing lever having mounted thereon a tilting
or pivoted platen adapted to take upon one of two type-wheels only, a spring or
other device normally causing it to take upon one and means to cause it to take
upon the other, substantially as set forth.
Eleventh. In a printing telegraph having two type-wheels, the combination of
an inked tape and means such as described for shifting or positioning the tape
under either wheel, substantially as set forth.
Twelfth. In a printing telegraph having two type-wheels, the combination of
an inked tape, a carriage therefor and a polarized magnet, controlling the position
of the tape and its carriage, substantially as set forth.
Thirteenth. In a printing telegraph having two type-wheels the combination of
an inked tape, a carriage therefor and a printing magnet and a polarized magnet
controlling the position of the tape, these magnets being in one circuit, substantially
as set forth.
Fourteenth. In a printing telegraph having two type-wheels, the combination
of the two type-wheels, a single platen, a single inked tape and means for
determining under which wheel the tape shall be positioned for printing,
substantially as set forth.
Fifteenth. In a printing telegraph, a unison device consisting of a stop upon the
type-wheel or upon a member of its train, a lever having a spring tending normally
to place it in the path of the stop, a printing magnet having an elongated core
operating on an armature connected to the lever, the magnet being in a constantly
charged circuit and holding the lever out of action, substantially as set forth.
Sixteenth. In a printing telegraph, a printing magnet controlling the printing
lover and having an elongated core for controlling also through the medium of an
armature lever, the unison devices, substantially as set forth.

page_text: Seventeenth. In a printing telegraph having two type-wheels, the combination
of an inked tape, a carriage therefor, a polarized magnet controlling the position
thereof, a printing magnet and a unison, the magnets controlling the printing,
unison and position of the tape being in one circuit, substantially as set forth.
Eighteenth. In a printing telegraph the combination of a magnet controlling
the printing mechanism and a magnet controlling the unison mechanism, both
located in a normally charged printing circuit, the breaking of which permits the
operation of the printing mechanism, throwing the unison lever out of action and
into effective range of the unison magnet, substantially as set forth.
Nineteenth. In a printing telegraph the combination of a unison lover, a
retractor tending to put the lever in action and a magnet normally holding the
same out of action, the magnet and retractor being so adjusted relatively to
each other that the magnet unaided cannot draw the lever out of action; and
means controlled by the printing mechanism to throw the lever within effective
range of the unison magnet, substantially as set forth.
Twentieth. In a printing telegraph the combination with a normally charged
printing circuit of a printing magnet and a unison magnet and a shunt circuit
around the unison magnet controlled by the escapement mechanism, substantially
as set forth.
In witness whereof, I, the said Herbert John Allison, have hereunto set my
hand and seal, this ninth day of August in the year of our Lord one thousand
eight hundred and eighty-three.
HERBERT. J. ALLISON. (L.S.)