IMPROVEMENTS IN TELEGRAPHIC RELAYS AND REPEATERS
Year: 1883

page_text: LETTERS PATENT to John Henry Johnson of 47 Lincolns Inn Fields in the
County of Middlesex Gentleman, for an Invention of "IMPROVEMENTS IN
TELEGRAPHIC RELAYS AND REPEATERS", communicated to him from James
Aloysius Maloney and Glen Walter Cooper persons residing at Washington
City, in the District of Columbia in the United States of America.
1:0
PROVISIONAL SPECIFICATION left by the said John Henry Johnson at
the Office of the Commissioners of Patents on the 27th November 1883.
a com-
JOHN HENRY JOHNSON of 47 Lincolns Inn Fields in the County of Middlesex
Gentleman "IMPROVEMENTS IN TELEGRAPHIC RELAYS AND REPEATERS."
munication [to him] from James Aloysius Maloney and Glen Walter Cooper
persons residing at Washington City in the District of Columbia in the United
States of America
The object of the invention is to obtain a relay or repeater which shall be very
much more sensible to weak currents than are instruments of that kind now in
general use, so as to permit long lines to be operated by battery power materially
less than that which must be employed under the present systems of telegraphy.
The aim of this Invention is to retain in the instrument as far as practically
maximum magnetic effects and at the same time to reduce to a minimum the extra
current effects; to decrease its internal resistance without imparing its efficiency ;
and to render its core capable of quickly charging and discharging.
The base of the instrument is made of wood or other insulating material
provided with binding posts connecting the electro magnet to line and also with
binding posts for the local circuit containing the sounder or other instrument
therein used. The two soft iron poles or horizontal legs of the electro magnet are
not solid but are composed each of a bundle of soft iron wires laid compactly
together and bound together in this position by rings. The two are connected at
the rear by screwing together soft iron socket pieces into which their rear ends
are inserted.
The magnet is so placed that the horizontal legs are in the same vertical plane,

page_text: Only one pole or leg of the electro magnet is covered by a helix; the other is
bare. The helix whose terminals are electrically connected to line posts as usual
is wound not in the ordinary way but in steps. The greatest number of coils is
at the front and they thence gradually decrease towards the neutral point. The
helix is covered by a sheath or shell of hard rubber or other insulating material
and the upper bare leg is brought down so as to lie in close proximity to the helix.
By using one helix only the extra current effects are materially reduced and the
reduction is further increased by making this helix of low resistance which is
accomplished by winding it in steps as mentioned for thus a mass of practically
useless wires is got rid of still preserving at the pole the number of coils which are
required to make the instrument efficient. And by making the legs of bundles of
soft iron wire, the charging and discharging of the poles takes place with much
greater rapidity.
All of these features together with the general arrangement of the magnet
relatively to its armature combine to render the instrument thoroughly efficient
and at the same time adapted to be worked by very weak currents and by small
battery power.
In front of the poles of the magnet is the armature lever which is made of soft
iron so as to constitute the armature also. It is pivoted in the usual manner in
a frame its axis of vibration being below the level of the lower pole and at right
angles with the vertical plane in which the two poles or legs lie.
There is the usual bracket through a hole in which (lined with insulating
material) passes the retractile armature spring which is provided with the
customary means for adjusting it. The said bracket carries the usual front and
rear adjusting screws for regulating the range of movement of the armature.
One screw has a tip of insulating material the other screw is the contact point
through which the local circuit is closed. The armature is in electrical connection
with one binding post and the bracket is electrically connected to the other
binding post of the local circuit.
The mode of operation of the instrument is similar to that of other relays and
requires no explanation.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said John Henry Johnson in the Patent Office on the 21st May
1884.
33
'a com-
JOHN HENRY JOHNSON of N° 47 Lincolns Inn Fields in the County of Middlesex
Gentleman "IMPROVEMENTS IN TELEGRAPHIC RELAYS AND REPEATERS
munication to me from James Aloysius Maloney and Glen Walter Cooper persons
residing at Washington City in the District of Columbia in the United States of
America
The object of the Invention is to obtain a relay or repeater which shall be very
much more sensible to weak currents than are instruments of that kind now in
general use so as to permit long lines to be operated by battery power materially
less than that which must be employed under the present systems of telegraphy.
The aim of this Invention is to retain in the instrument, as far as practicable,
maximum magnetic effects and at the same time to reduce to a minimum the
extra current effects; to decrease its internal resistance without impairing its
efficiency; and to render its core capable of quickly charging and discharging.
The accompanying drawing represents a relay embodying the several
improvements.
Figure 1 is a side elevation of the instrument and Figure 2 is a plan of the
same.
Figure 3 is a side elevation partly in section of the electro magnet detached.
Figure 4 is a front elevation of the two cores of poles of the magnet and
Figure 5 is a front elevation of the armature detached.
The base of the instrument is made of wood or other insulating material.
The binding posts 1, 2 connect the electro magnet to line; and the binding
posts 3, 4 are for the local circuit, containing the sounder or other instrument
therein used.
The two soft iron poles or legs of the electro magnet are shown at A, B. They
are not solid but are composed each of a bundle of soft iron wires laid compactly
together and bound together in this position by rings a. The two are connected
at the rear by screwing together the soft iron socket pieces b into which their rear
ends are inserted.
The magnet is so placed that the horizontal legs A, B, are in the same vertical
plane.
Only one pole or leg, A, of the electro magnet is covered by a helix; the other B
is bare. The helix A whose terminals are electrically connected to line posts 1, 2
as usual is wound not in the ordinary way but in steps as shewn in section in
figure 3. The greatest number of coils is at the front and they thence gradually
decrease towards the neutral point. The helix is covered by a sheath or shell c of
hard rubber or other insulating material and the upper bare leg B, is brought-
down so as to lie in close proximity to the helix.
By using one helix only the extra current effects are materially reduced and the
reduction is further increased by making this helix of low resistance which is
accomplished by winding it as represented in the drawing, for thus a mass of
practically useless wires is got rid of while preserving at the pole the number of
coils which are required to make the instrument efficient. And by making the
legs of bundles of soft iron wire the charging and discharging of the poles takes
place with much greater rapidity.
All of these features together with the general arrangement of the magnet
relatively to its armature combine to render the instrument thoroughly efficient
and at the same time adapted to be worked by very weak currents and by small-
battery power.

page_text: In front of the poles of the magnet is the armature lever C which is made of
soft iron so as to constitute the armature also. It is pivotted in the usual manner
in the frame c¹, its axis of vibration being below the level of the lower pole A and
at right angles with the vertical plane in which the two poles or legs lie.
Dis the usual bracket through a hole d in which (lined with insulating material)
passes the retractile armature spring e which is provided with the customary
means for adjusting it. The bracket carries the usual front and rear adjusting
screws f, g, for regulating the range of movement of the armature. The screw f
has a tip of insulating material; the other screw g is the contact point through
which the local circuit is closed. The armature is in electrical connection with the
binding post 3, and the bracket is electrically connected to the binding post 4, as
indicated in Figure 2.
The mode of operation of the instrument is similar to that of other relays and
requires no explanation.
T
I am aware that an electro-magnet having one only of its legs provided with a
coil is not new and I am also aware that it is not new to form the legs of an
electro-magnet of a bundle of soft iron wires. But I am not aware that a relay or
other main line telegraphic instrument has ever before this Invention been devised,
characterised by the combination of these elements in connection with an armature
under the arrangement hereinbefore described, whereby the resistance is made low
the extra current effects are materially lessened, and the charge and discharge are
caused to take place with great rapidity all of which features combine to enhance
the efficiency and working capacity of the instrument and to permit a material
reduction of the battery power for operating it.
Having now described and particularly ascertained the nature of the said
Invention and the manner in which the same is or may be used or carried into
effect I would observe in conclusion that what I consider to be novel and
original and therefore claim as the Invention secured to me by the hereinbefore in
part recited Letters Patent is :—
First: In a telegraphic relay or similar main line telegraphic instrument, an
electro-magnet having legs formed of bundles of soft iron wire (one leg being
provided with a coil or helix and the other leg being bare and placed in close
proximity to the covered leg), in combination with an armature electrically
independent of the said magnet and arranged so as to vibrate in front of both
magnet poles, substantially as and for the purposes hereinbefore set forth.
Second-The combination of the legs A. B formed of bundles of soft iron wire,
and the helix or coil A wound in steps so as to gradually reduce the mass of wire
in the direction of the neutral point, substantially as hereinbefore described.
Third-The combination with the two soft iron legs of an electro magnet,
whether solid or formed of bundles of wire, of a helix surrounding one leg only
and wound in steps so as to gradually reduce the mass of conducting wire in the
direction of the neutral point, substantially as hereinbefore described.
47
In witness whereof I the said John Henry Johnson have to this my Specification
set my hand and seal this twentieth day of May One thousand eight hundred
and eighty four