IMPROVEMENTS IN PRINTING TELEGRAPHS
Year: 1884

page_text: PROVISIONAL SPECIFICATION.
-
"
I WILLIAM HENRY DAVIES Managing Director of the Exchange Telegraph
Company Limited of 17 and 18 Cornhill in the City of London, do hereby declare
the nature of my invention for "IMPROVEMENTS IN PRINTING TELEGRAPHS
(a communication to me from abroad by George B. Scott of Brooklyn New York
one of the United States of America Telegraph Engineer) to be as follows :—
This Invention has for its object improvements in printing telegraphs.
For the purpose of directing short and rapid reversals upon the line I provide a
circuit wheel the periphery of which is composed of an equal number of conducting
and insulating spaces the total number being equal to the number of characters
upon the type wheel. This circuit wheel is firmly placed upon a shaft or arbor and
is frictionally geared to any suitable motor for imparting rotation thereto. The
conducting sections in the periphery of the wheel are in electrical communication
with a hub upon the periphery of which bears a spring or finger which is in
connection with the line wire. Upon the periphery of the circuit wheel two spring
fingers are placed. Each finger is connected to an independent generator of
electricity respectively of opposite polarity. The conducting spaces upon the
periphery of the circuit wheel are slightly shorter than the insulating spaces and
the points of contact of such fingers upon the periphery of the said wheel are
circumferentially separated by a space equal to the length of an insulating space.
As the circuit wheel rotates a conducting space passes under the first finger and
thereupon a pulsation of one polarity is thrown upon line and simultaneously with
the disconnection of that space from the first finger said space passes under. tho
second finger and directs a pulsation of opposite polarity upon line and at the same
time an insulating space passes under the first finger. In this way alternately
opposite impulses are directed to line. The means for stopping rotation of the type
wheel and prolonging a pulsation consists of an arm firmly fixed to the rotating
shaft bearing the circuit wheel. On a fixed support a series of electro magnets-
one for each character of the type wheel are arranged equidistant in the circum-
ference of a circle or in two concentric series. Each electro magnet is connected
by a separate wire with the corresponding circuit closing key of a key board.

page_text: Each electro magnet has a moveable stop controlled by its armature and normally
resting slightly withdrawn from the plane of rotation of said arm. When an
electro-magnet is energized by completion of its circuit at the normally open key,
such stop is projected into the path of the rotating arm thus stopping rotation of
the shaft and circuit wheel and thus continuing the pulsation last directed to line.
It is to be understood that the position of the electro-magnet corresponding to any
character of the type wheel and the fixed arm are to bear such a relation to each
other that when the fixed arm is arrested by the operation of such electro magnet
as aforesaid the character of the type wheel corresponding to such electro-magnet
will be in position to yield an impression.
Upon the axis of the type wheel I provide an escape wheel having what are
technically known as "recoil teeth ">
or teeth whose faces form angles with the
radial lines drawn from the points of the teeth to the centre of motion. In
connection with the recoil teeth upon the escapement wheel I employ an escape-
ment yoke the two pallets of which have double inclined surfaces so arranged that
in the rotation of the escapement wheel any tooth thereon approaching a pallet of
the escapement yoke will strike upon the inclined surfaces thereof and tend to
drive it to one sido. At an obtuso angle with the first inclined surface of a pallet is
a second inclined surface whose position is such that on a reverse movement of the
escapement yoke a second inclined surface will impinge upon the next succeeding
tooth of the escapement wheel providing in the meantime the escapement wheel
has not rotated a portion of a step under the influence of the motor, as it should
have done and by such impingement the pallet will act positively to drive the
escapement wheel through the space of one step of rotation. In the case of a dead
beat escapement as distinguished from a recoil escapoment the to and fro movement
of the escapement yoke is comparatively slow as to inertia and the friction between
its pallets and the teeth of the escapement wheel must be wholly overcome by the
electro magnetic influence of the escapement magnets and in that case the force of
the motor which tends. to rotate the escapement wheel increases bearing pressure
and the friction between the pallets of the escapement yoke and the teeth of the
escapement wheel. In my arrangement however the recoil teeth of the escapement
wheel and the inclined surfaces of the pallets of the escapement yoke enable the
action of the motor of itself to give the escapement yoke a rapid to and fro
vibration.
In the operation of printing telegraph instruments it frequently occurs that after
a strip of paper upon which the message is printed has been pressed against the
characters of the type wheel said paper strip will not be quickly withdrawn. If an
impulse to rotate the type wheel be sent to line during a prolonged adherence of
the paper strip to the type wheel- the type wheel will be arrested while it should
have taken one or more steps of rotation thereby throwing it out of unison. This
defect in operation is very common where dead beat escapements are employed.
My device however affords means for positively driving the type wheel at each to
and fro rotation of the escapement pallets whether tho action of the motor is or is
not sufficient to cause rotation. I first therefore give the weight or clock motor a
capacity for accelerating the to and fro vibrations of the escapement" yoke, and
secondly, I give the escapement pallets a capacity for assisting the clock or weight
motor in the operation of rotating the type wheels.

page_text: COMPLETE SPECIFICATION.
I, WILLIAM HENRY DAVIES, Managing Director of the Exchange Telegraph
Company Limited of 17 and 18 Cornhill in the City of London do hereby declare
the nature of my invention for IMPROVEMENTS IN PRINTING TELEGRAPHS" (a
communication to me from abroad by George B. Scott of Brooklyn New York one
of the United States of America, Telegraph Engineer) and in what manner the
same is to be performed to be particularly described and ascertained in and by tho
following statement :-
The object of the first part of my invention is to furnish an improved transmitter
for printing telegraph instruments whose type-wheels are rotated step by step by
short reversals of line-current, and from which impressions are taken by prolonging
a pulsation of either polarity.
My invention consists, first, of means for directing upon the main line short and
rapid reversals of electricity to rotate the type-wheel; and, second, means for
stopping the type-wheel at any desired character and means for prolonging an
impulse for the taking of an impression from the type-wheel. For the purpose of
directing short and rapid reversals upon the line, I provide a circuit wheel, the
periphery of which is composed of an equal number of conducting and insulating
spaces, the total number being equal to the number of characters upon the type-
wheel. This circuit wheel is firmly placed upon a shaft or arbor, and is frictionally
geared to any suitable motor for imparting rotation thereto. The conducting-
sections in the periphery of the wheel are in electrical communication with a hub,
upon the periphery of which bears a spring or, finger which is in connection with
the line-wire. Upon the periphery of the circuit-wheel two spring fingers are
placed. Each finger is connected to an independent "generator of electricity,
respectively of opposite polarity. The conducting spaces upon the periphery of the
circuit-wheel are slightly shorter than the insulating spaces, and the points of contact
of such fingers upon the periphery of the said wheel are circumferentially separated
by a space equal to the length of an insulating space. As the circuit-wheel rotates,
a conducting space passes under the first finger, and thereupon a pulsation of one
polarity is thrown upon line, and simultaneously with the disconnection of that
space from the first finger said space passes under the second finger and directs a
pulsation of opposite polarity upon line, and at the same time an insulating spaco
passes under the first finger. In this way alternately opposite impulses aro directed
to line. The means for stopping rotation of the type-wheel and prolonging a
pulsation consists of an arm firmly fixed to the rotating shaft bearing the circuit-
wheel. On a fixed support a series of electro-magnets-one for each character of
the type-wheel-aro arranged equidistant in the circumference of a circle, or in two
concentric series. Each electro magnet is connected by a separate wire with the
corresponding circuit closing key of a key board. Each electro magnet has a
movable stop controlled by its armature, and normally resting slightly withdrawn
from the plane of rotation of said arm. When an electro magnet is energised by
completion of its circuit at the normally open key, such stop is projected into the
path of the rotating arm, thus stopping rotation of the shaft and circuit wheel, and
thus continuing the pulsation last directed to line. It is to be understood that the .
position of the electro-magnet corresponding to any character of the type-wheel,
and the fixed arm are to bear such a relation to each other that when the fixed
arm is arrested by the operation of such electro magnet, as aforesaid, the character.

page_text: of the type wheel of the receiving instrument corresponding to such electro magnet
will be in position to yield an impression.
"
In escapement devices ordinarily employed for the rotation of type-wheels their
release and step by step rotation are effected by a to and fro movement of the
escapement yoke through the agency of electro magnets in a main line.
The object of my invention is to provide an escapement apparatus in which the
to and fro movement of the escapement yoke is effected, not by the escapement
electro-magnets alone, but by the combined action of the motor which is usually
employed to rotate the escapement wheel when released and the escapement
electro-magnets.
•
A further object of my invention is to so construct the pallets of the escapement
yoke that they may, in case the escapement wheel should happen not to be readily
rotated by its motor, have a positive driving capacity to rotate said escapement
wheel step by step. To this end I employ an escape wheel having what are
technically known as "recoil-teeth," or teeth whose faces form angles with the
radial lines drawn from the points of the teeth to the centre of motion. In
connection with the recoil teeth upon the escapement wheel I employ an
escapement yoke the two pallets of which have double inclined surfaces so arranged
that in the rotation of the escapement wheel any tooth thereon approaching a
pallet of the escapement yoke will strike upon the inclined surfaces thereof and
tend to drive it to one side. At an obtuse angle with the first inclined surface of
a pallet is a second inclined surface, whose position is such that on a reverse
movement of the escapement-yoke a second inclined surface will impinge upon the
next succeeding tooth of the escapement-wheel, providing in the meantime the
escapement wheel has not rotated a portion of a step under the influence of
the motor; as it should have done, and by such impingement the pallet will act
positively to drive the escapement wheel through the space of one step of rotation.
In the case of a dead beat escapement, as distinguished from a recoil escapement,
the to and fro movement of the escapement-yoke is comparatively slow, as its
inertia and the friction between its pallets and the teeth of the escapement wheel
must be wholly overcome by the electro-magnetic influence of the escapement-
magnets, and in that case the force of the motor which tends to rotate the
escapement wheel increases bearing pressure and the friction between the pallets of
the escapement-yoke and the teeth of the escapement wheel. In my arrangement,
however, the recoil teeth of the escapement wheel and the inclined surfaces of the
pallets of the escapement yoke enable the action of the motor of itself to give the
escapement-yoke a rapid to and fro vibration.
In the operation of printing telegraph instruments it frequently occurs that after
a strip of paper upon which the message is printed has been pressed against the
characters of the type-wheel, said paper strip will not be quickly withdrawn. If
an impulse to rotate the type wheel be sent to line during a prolonged adherence
of the paper strip to the type-wheel, the type wheel will be arrested, while it
should have taken one or more steps of rotation, thereby throwing it out of unison.
This defect in operation is very common where dead-beat escapements are employed.
My device, however, affords means for positively driving the type wheel at each
to and fro rotation of the escapement-pallets whether the action of the motor is or
is not sufficient to cause rotation. I first, therefore, give the weight or clock motor
a capacity for accelerating the to and fro vibrations of the escapement-yoke; and
secondly, I give the escapement-pallets a capacity for assisting the clock or weight
motor in the operation of rotating the type-wheels.
I will now describe my invention by reference to the accompanying drawings.
Referring to the drawings, Figure 1 is a general view of the transmitter and its
connections with the generators. Figure 2 is a detail sectional view of one of the
electro magnets, all of which are alike used for stopping rotation of the shaft, and
the circuit-wheel for directing reverse pulsations to line. In these figures s is a
shaft, to which is frictionally geared a motor of any suitable construction (not
shown) firmly fixed to this shaft is the circuit-wheel C, the periphery of which is

page_text: divided into conducting and insulating spaces; the former being slightly shorter
than the latter. They should be equal in number, equidistant, and together equal
in number to the number of characters upon the type-wheel. . The conducting
portion of wheel C is electrically connected to a hub or roller h, upon which bears
an arm H, to which the line-wire is connected. Two spring-fingers f, f¹, rest upon
the periphery of the wheel with sufficient force to form a good electrical connection
therewith. These fingers are circumferentially distant from each other at contact
and upon the periphery of wheel C a space about equal to the length of one of the
insulating-sections on the periphery of C. Finger serves to connect generator of
electricity D of one polarity to line, and f' similarly serves to connect generator D¹
of opposite polarity to line. As the circuit wheel C revolves in connection with the
line fingers fand f', each alternately rests upon a conducting space and an insulating
space, and vice versa. Thus a continuous series of reversals are directed to line.
Firmly fixed to shaft 8 is an arm A.
P is a standard or fixture located in a plane parallel to but slightly distant (say
a fraction of an inch) from the plane of rotation of arm A. A series of electro-
magnets m, are located in this support, and are in number equal to the number of
characters upon the type wheel. They are equidistant, and are placed in the
circumference of a circle of which the arm A forms the radius. These magnets
have a hollow core c, through which passes a bar of brass or other non-magnetic
material b, Figure 2 to which the armature a is securely fixed. The free end of
bar b normally rests but slightly removed from the plane of rotation of arm A.
When the armature a is attracted, bar bis given a longitudinal movement, carrying
it into the path of arm A, by which means arin A, shaft 8, and wheel C are arrested,.
and a conducting section of wheel C will rest under either for f', by which means
the last reversal directed to line is continued or prolonged. Each magnet is
connected with a circuit closer or key by an independent wire connecting with a
common battery, and by this means the series of key circuit-closers may be located
at any desired distance from the main line pulsater or transmitter.
When the instruments are not in operation, arm A is at a zero position, as are
also the type wheels of the receiving instruments. By depressing any particular
key after arm A has been released, a series of current-reversals will be sent to line
before the arresting of A, sufficient in number to bring that character of the type
wheel opposite the press-pad, which corresponds with the character represented by
the depressed key..
Figure 3 of the drawings illustrates the construction of the receiver.
In this figure N is an escapement wheel having recoil teeth 1. 2. 12. 13.
<
T is a type-wheel, which is rigidly connected with escapement-wheel N upon
shaft D, to which a constant tendency to rotation is imparted by the weight W,
cord C, and an interposed gear train.
M is an escapement yoke pivotted at g, having pallets x y and adjustable set
screws c. f. for limiting its to and fro movement.
A A¹are escapement electro-magnets for controlling the vibration of escapement-
yoke M.
•
P is a press magnet controlling an armature lever p p, to which is attached a
platen for impressing a strip of paper upon the characters upon the periphery of
the type wheel. Pallet is provided with two inclined surfaces a d, and pallet y
with corresponding inclined surfaces bc. In the normal rotation of the escapement
wheel, if the escapement yoke has moved to its extreme left position, the point of
tooth 2 would have passed by the point of pallet x, and thereupon the point of
tooth 12, through the agency of the motor, impelled by weight W, would be
immediately thrown against the inclined surface c of pallet y. The impinging of
tooth 12 upon surface c would conspire with electro-magnets A A¹ to immediately
move the escapement-yoke from its extreme left position toward the right, and the
escapement-wheel would continue to rotate until the point of tooth 12 had passed
the point of pallet y. Upon the point of 12 passing the point of pallet y the
escapement-wheel again has a second free movement of rotation under the action

page_text: of the clock motor until the point of tooth 1 comes in contact with the inclined
surface d of pallet x. However, if after the escapement yoke has reached its extreme
left position, the rotation of the escapement-wheel under the influence of the motor
be arrested by a failure to withdraw the paper from the periphery of the type-
wheel, the reverse movement of the escapement yoke toward the right will bring
the inclined surface a of pallet a against the point of tooth 2, and will thereby
positively drive the escapement-wheel N until the point of tooth 12 is just past the
point of pallet y. If the type-wheel again fail to rotate under the action of the
motor, the reverse movement of the escapement pallets to the left will bring
the inclined surface of d to bear upon the point of tooth 12, and the escapement
wheel will be positively driven another step, and so on. The type-wheel is beld
during an impression by a prolonged impulse of either polarity.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed I declare that what
I claim is
1. A main line circuit pulsator and reverser, C, whose periphery is alternately
composed of insulating and conducting portions, conducting springs f, f¹, respective
generators D D¹, main line L, shaft s, arm A, and a circular series of stop electro-
magnets m, substantially as described in respect to Figures 1 and 2.
2. The combination of shaft 8, rotating arm A, support or standard P, a circular
series of stop electro-magnets m, mounted on said standard or support, said electro-
magnets m having an axial core of non-magnetic material b, and an armature a
substantially as described in respect to Figures 1 and 2.
3. The combination of the rotating arm A, the circular series of stop electro-
magnets m, whose ends are embedded in support P, each of said electro-magnets
having an axial core of non-magnetic material b, and an armature a, substantially
as described in respect to Figures 1 and 2.
•
4. The combination of a stop electro-magnet m, whose ends are embedded in
the support P, adapted to arrest a rotating arm A, consisting of a coil of wire
wound upon a hollow iron core c, a movable axial core of non-magnetic material b,
adapted to project into the path of A, and armature a, substantially as described in
respect to Figures 1 and 2.
5. The combination of an escapement-wheel for printing-telegraphs having
recoil teeth, with double inclined surfaces, as set forth, and escapement pallets
provided with double inclined surfaces, substantially as described.
6. The combination of an escapement-wheel having recoil teeth, and a clock or
other motor for driving the same, and inclined surfaces upon the escapement pallets,
substantially as described, for aiding said motor to rotate the escapement-wheel.
7. The combination of a type-wheel, an escapement-wheel having recoil-teeth,
and a motor for driving the same, an escapement-yoke having pallets provided with
inclined surfaces, substantially as described, for enabling the motor which drives
said escapement wheel to accelerate the vibrations of the escapement-yoke, and
electro-magnets for controlling said vibration."
8. The combination of an escapement-wheel.and a motor for rotating the same,
an escapement yoke controlled by electro-magnetism, said yoke being provided with
pallets having inclined surfaces, substantially as described, for positively aiding the
motor to rotate said escapement wheel.