IMPROVE- MENTS IN ELECTRIC TELEGRAPHS AND IN APPARATUS CONNECTED THEREWITH
Year: 1879

page_text: LETTERS PATENT to Sir Charles Tilston Bright, of 11, Delahay Street, West-
minster, in the County of Middlesex, Knight, for the Invention of "IMPROVE-
MENTS IN ELECTRIC TELEGRAPHS AND IN APPARATUS CONNECTED THEREWITH."
Sealed the 9th May 1879, and dated the 27th February 1879.
PROVISIONAL SPECIFICATION left by the said Sir Charles Tilston Bright
at the Office of the Commissioners of Patents on the 27th February 1879.
Sir CHARLES TILSTON BRIGHT, of 11, Delahay Street, Westminster, in the County
of Middlesex, Knight. "IMPROVEMENTS IN ELECTRIC TELEGRAPHS AND IN
APPARATUS CONNECTED THEREWITH."
My Invention consists in improvements in the apparatus used at the receiving
end of a telegraphic circuit, whereby such apparatus is rendered more sensitive and
decided in its action, and can be worked by a smaller electrical power. It is
applicable to telegraphic instruments generally, and to railway signals and fire
alarms.
In the receiving apparatus hitherto employed for signalling to the eye or ear, or
for recording or type printing telegraph instruments, the moving part (whether
magnet, armature, or coil of wire) has been brought back to its place of rest or zero
by the action of a spring, or weight, or magnot, the controlling force of which has.
first to be overcome by the power of the electrical current upon such moving part
before the signal is given.
In my Invention I withdraw (wholly, or in some cases partly) the opposing
force of the spring or other retarding agent by causing the current to act simul-
taneously upon an auxiliary armature, which is linked or connected to the signalling
magnet. The latter may either give signals to the eye or ear, or may actuate a
local circuit comprising a recording or a type-printing instrument.
When no current is passing through the conducting wire the auxiliary armature
retains the signalling magnet at zero by means of the link or connection, but on a
current passing the signalling magnet is freed from the control of the auxiliary
armature, and the movement of the signalling magnet may also be assisted by the
thrust of the link.
In place of the signalling magnet which I have described there may be used for
signalling direct or for connecting a local circuit either an armature or a coil of

page_text: .
wire ;
and similarly the auxiliary armature referred to may be replaced by an
auxiliary magnet or a coil of wire."
In applying my Invention to instruments where very great delicacy of motion is
essential (as in the case of the mirror and the siphon recording instruments used on
long submarine cables) which are suspended as to the signalling magnets or coils
by threads or wires I connect the latter to the auxiliary armature direct, which
causes the tension or torsion to be relaxed when the current is passing.
In applying my Invention to the ordinary needle instruments I remove the
galvanometer coils and the movable vertical magnet, together with its horizontal
axle, and in place thereof I fix vertically two bar electro magnets parallel with each
other. Upon an horizontal axle (which passes through the dial plate of the instru-
ment and carries the usual external indicator) I fix a soft iron arm which is
polarised by a stationary permanent magnet adjacent to its axis, and which moves
between the poles at one end of the pair of electro magnets, a positive current
deflecting the arm to one side and a negative current to the other side. Opposite
to the poles at the other end of the pair of electro magnets an auxiliary soft iron
armature is placed which is attracted to the electro-magnets both by a positive and
by a negative current.
The armature is linked to the above mentioned soft iron arm by a light con-
necting rod, or by wire, silk, hair, or any suitable material.
An adjustable spring holds back the armature a very small distance from the
poles of the electro magnet when no current is passing, and at the same time by
means of the connection keeps the movable arm at zero. Upon a current passing
the armature relaxes the connection with the arm, which is then free to move
against stops on either side, accordingly as the current is positive or negative, and
upon the current ceasing it is brought back to zero again by the tension of the
spring.
By this means a much more definite and rapid signal is obtainable on both sides
of zero, while the battery power requisite is greatly reduced.
I also cause the motion of the moving arin to be stopped by appliances for giving
sounds, such as plates or belts of glass or metal, so that signals may be made to
the ear as well as to the eye.
A similar arrangement to that described above is well adapted for relays (or
apparatus for completing a local circuit), and in this case, where great sensitiveness
is required, I place the moving arm between the poles of four electro magnets, and
I bring to bear the combined action of all of them upon the moving arm and also
upon the arrangement for bringing it back to zero.
In another part of my Invention I cause two armatures or magnets, or the arms
prolonged from them, to make contact against each other, and by causing a single
electrical current to actuate both the armatures or magnets at the same time I
greatly reduce the movement necessary for making contact while the pressure of
the contact is also increased.
My Invention both as regards this part of it and the means of neutralising or
relaxing the tension previously described may be readily applied to most of the
various forms of relays by slightly modifying the new parts to suit the different
modes of construction.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Sir Charles Tilston Bright in the Great Seal Patent Office on the
23rd August 1879.
Sir CHARLES TILSTON BRIGHT, of 11, Delahay Street, Westminster, in the
County of Middlesex, Knight. "IMPROVEMENTS IN ELECTRIC TELEGRAPHS AND
IN APPARATUS CONNECTED THEREWITH."
My Invention consists of improvements in the receiving parts of electric telegraphs
by which they are rendered more sensitive and decided in their action. In the
receiving apparatus hitherto employed, in which a complete signal is made by a
single current, the moving part is brought back to its place of rest or zero by a
spring, or by one portion of the moving part being heavier than another, or by an
electro-magnet being polarised by a permanent magnet. In these methods of con-
trolling the moving parts of receiving apparatus the magnitude of the signal given
or the force with which contact is made when a local circuit is made by such moving
part represents only the difference between the power of the electrical current
employed and the force of the controlling agent. In my improvements the moving
part of the receiving apparatus by which the signal is given or the contact is made,
whether it be a magnet, a soft iron armature, or a coil of insulated wire, is controlled
by a second moving part which is worked by the same current in such a manner as
to withdraw all restraint from the first or signalling part while the current is
passing and to bring it back to zero and retain it there when no current is passing.
At Fig. 1 of the Drawings is shown the front elevation of a relay constructed
upon this system and adapted for making contact on either side, according as a
positive or a negative current is sent. a, a', are two electro magnets fixed vertically
on an upright frame which have opposite poles when a current is passes through
them; b is a permanent magnet presenting one of its edges to view; it works upon
a centre at c and is influenced by the poles d, d, of the electro magnets; e, e¹, are
two insulated contact screws; f is a soft iron armature acted upon by g, g¹, the
upper poles of the electromagnets; h is an adjustable spring. b is joined to ƒ by i,
which is a hair, or thread, or piece of fine wire. When no current is passing the
springh holds back the armature f as far as the connexion off with 6 by i will
allow, and b is thus retained at zero, the contact piece k at its lower end being
midway between e, el. Upon the passage of a current whether positive or negative
fis attracted by 9, g', its control over 6 by means of i ceases for the time, and b is
free to move without any retarding force to either side, according to the direction of
the current.
When a current of one kind only is used, as with the ordinary Morse alphabet,
a soft iron armature may be advantageously used in place of a magnet. At
Fig. 2 is shown a plan, and at Fig. 3 a side elevation of an instrument so con-
structed, the letters in the Figures referring to the same parts; a, a¹, are two electro
magnets fixed horizontally; b is a soft iron armature carried by a lever c working
on its centre d. The armature b enters between the poles of the electro magnets in
the manner shown at f in Figure 1; e is an armature at the other end of the
electro magnets fixed to the lever f which works on its centre g; f is connected
to c by the thread h; i, i, are two metallic reeds or sounders which are only shown
in Fig. 2 with projecting pins j, j; they are insulated from each other and by con-
necting g to one side of a local circuit and to the other, the signals may be read
by sound and be recorded at the same time; is an adjustable spring by which,
when no current is passing, b and c are drawn away from the poles of a, a', as far
as is permitted by the connexion h, the tension of which derived from the spring k
through c causes f, e, to press against j. Upon a current passing, the action of k
upon his withdrawn by the attraction of 6 to a, a³, and ħ is moved against ; by the
attraction of a to a at

page_text: At Figures 4 and 5 are shown the front and side elevations of an example of the
application of my system to an instrument for indicating signals by the motion of
a mirror; a, a¹, are two vertical electro magnets, a being removed in Fig. 5 to
show the parts between them; b is a light permanent magnet of the horse shoe
form to which is fixed the small mirror c; b and c are attached by the thread or
fibre d to the armature e which is suspended from the frame of the instrument by
the adjustable spring f. The lower ends of the limbs of b are attached to a pin h
projecting from the frame by the threads g, g²; i and kare guides by which the
armature spring and thread are kept in a vertical line with each other. The
tension upon g, g³, communicated through d from ƒ keeps b and c at zero when the
circuit is at rest, but when a current passes, the tension is relaxed and the action of
the lower poles of a, a', upon b causes it together with c to move axially upon d
in one or the other direction, according to the current sent.
Upon the cessation of the current the tension is renewed, and b and c return
towards their plane of rest.
In applying my improvements to the ordinary needle instrument I remove its
galvanometer coils and the movable vertical magnet, and in place thereof I fix
vertically two electro magnets parallel with each other which are shown at a, a',
Figure 6. A permanent magnet b fixed to the frame of the instrument carries a
soft iron arm c, c, working in pivots at the end of the permanent magnet by which
it is polarised. d is the axle which carries the indicating needle on the other
side of the frame, and on the side presented to view a vertical arm which has at its
lower end a pin which enters into a slot or fork at the upper end of c. e is an
armature which is attracted to the electro magnets both by a positive and a negative
current. A pin fat the end of the lever upon which e is fixed is connected by the
thread g to the top of the arm fixed upon axle c. h is an adjustable spring by
which is held up as far as the connexion with & will allow, thus keeping the arm
(and the indicating needle on the other side of the frame) at zero when no current
is passing. The lower part of c, c, is prolonged by a piece of non-magnetic metal i,
and the weight above and below the axis of c, c, d, should be equal. j, j, are reeds
of metal or glass, or bells, with adjustable pins against which i is stopped, so that
signals may be made to the ear, as well as by the external indicating needle to the
eye. jj, may be insulated to be used as contact stops if it is also desired to use a
local circuit for the purpose of recording the signals. On a current passing, the
armature relaxes the connexion with the arm, which is then free to move on which-
ever side it is propelled by c, c, and upon the current ceasing it is brought back to
zero again by the tension of the spring, taking with it c, c. By this means a much
more definite and rapid signal, both visual and acoustic, is obtainable on both sides
of zero than can be got with any previous form of needle instrument; while the
battery power requisite is greatly reduced.
In place of the thread, hair, or fibre which I have described, a link may be used
for the connexion between the two moving parts of the receiving apparatus, as
shown at Fig. 7, where a, c, is a light connecting link (which may be made of
aluminium or steel) attached at its upper end to the armature or its lever by pivot a,
and at its lower end to the top of the magnet b by pivot c. By this arrangement
the movement of the magnet (and the pressure of the contact in the case of a relay)
is also assisted by the thrust of the link, as illustrated by the dotted lines. I have
so far described my system of controlling the signalling part of a relay by means of
a second moving part, as being effected by a connexion between the said parts
attached to both of them, but this attachment is not essential to my Invention, as,
for example, at Fig. 7, d is an armature, and e a magnet, actuated by the same pair
of electro magnets (which are not shown). The spring f, which is fixed to the
armature lever on the further side of the axle lifts the armature from the poles of
the electro inagnets, and brings the angular correcting piece g, which is at the end
of the armature lever nearest to view against the end of the magnet e, so as to keep
it at zero when no current is passing. When a current is sent the armature on the

page_text: other side of the axle is attracted downwards, the correcting piece is lifted, and
simultaneously the magnet is moved to one or the other side by the current.
At Figure 8 is shown the side elevation of a receiving instrument in which the
control is exercised by the auxiliary armature by means of a piece of thread or
other suitable material, which is fastened at one end to the end of the lever of the
armature, and after passing through an eye or fork in an arm fixed to the axle of
the magnet by which the signals are given, is fastened at its other end to the frame
of the instrument. a, Figure 8, is one of a pair of vertical electro magnets, the
other (which would be nearest to view) being removed in order to show the parts,
between them; b is a permanent magnet of the horse shoe form fixed to the hori-
zontal axle c, which also carries the external indicating needle d on the other side
of the upright frame of the instrument; e is a crank shaped arm fixed to c, having
an eye at its end through which the thread f. f, passes, the eye being sufficiently
large to allow it to move freely without being too slack; g is a key to which the
lower end off, f, is fastened, and h, h¹, are two guides through which the thread
passes; i is a split shot fastened to f, f, above h; j is the armature lever; k, the
spring; and , the adjusting screw. The action of the instrumont is the same as
in the other examples which I have given, the magnet b being kept at zero when
the controlling thread f, f, is taut, and being free to move when it is slackened by
a very small movement of f.f. The upper part of 6 should be so much heavier
than the lower part as to balance the weight of e; m is a stop against which j is
brought when the current ceases. It is not essential but renders the return to zero
more steady when the thread f.f, is accurately adjusted by g so as to be just taut
when rests against m. At Fig. 9 a similar mode of arranging a controlling
thread is shown as applied to a novel mode of making contact, which is of great
utility under certain circumstances. a, a, Fig. 9, is a thread passing through a
fork in the segment of a circle c attached to a magnet d, which is represented in
this case as being actuated by galvanometer coils. The magnet is not fixed as
usual to an axle working between centres but to two segments of a circle of which c
is one, the other being opposite to c, and immediately behind it in the Figure on
the other side of the coils; dis a guide to keep the thread vertical. The segment c
when at zero rests upon an insulating plate (such as a piece of a gate) between e
and f, which are insulated from each other and connected to a local circuit. The
segment on the other side rests on a metallic plate, which is connected to the
battery belonging to the local circuit. It has a similar controlling thread to a, a,
actuated by the same force when the current passes. On a current being sent the
segments move with a rolling motion to one or the other side, contacts being made
by their weight, and the local circuit being made and broken on one or the other
side, according to the nature of the currents sent and the intervals between them.
Fig. 10 shows an arrangement suitable for making a number of different contacts,
according to the magnitude of the movement of the segments, the letters of which
refer to the same description as that given for Fig. 9. Wheels may be substituted
for the segments with advantage where great delicacy of action and a perfect
balance of the parts are requisite, and this system of making contact is applicable
to most of the arrangements of coils and magnets or armatures in use.
At Fig. 11 is shown the top view of an improvement upon the customary
manner of making contact for joining up a local circuit by the pressure of the
moving part of the receiving instrument against a fixed stop. a, Fig. 11, is the
upper coil of a pair of electromagnets which are arranged in side elevation in the
same manner as the electro-magnets shown at Fig. 3; b, b', are two armatures
working on centres at c, c'; d, d³, are their adjusting springs. The ends of their
levers e, e¹, are stopped by screws f, f, when the apparatus is at rest. Upon a
current passing, e and e¹ are brought into contact with each other, and upon its
cessation they separate from each other. By this improvement the movement
necessary for making contact is divided between the two armatures, so that each
of them has only to move half the distance which would be ordinarily necessary
where a single armature is used, and the pressure is at the same time greatly

page_text: increased. Two magnets may be used in place of the two armatures. At Fig. 12
is shown an example in plan of the application of this part of my improvements to
my system of withdrawing tension during the passage of a current, as described in
the previous Figures. a, a¹, are two pairs of electro magnets similar to those shown
in Figs. 2 and 3; b, b, are two armatures controlling c, c', by the threads d, d', and
the operation of the instrument is practically similar to that of the apparatus
described in reference to Figures 2, 3, and 11.
Having now described the nature of my said Invention, and the manner in which
the same is to be performed, I would remark that I do not restrict myself to the
special forms of apparatus described for the purpose of carrying out my improve-
ments, as various modifications may be devised with the same object; but what I
claim and desire to be secured to me by the herein in part recited Letters Patent
are, Firstly. The methods of controlling the moving parts of the receiving apparatus
of electric telegraphs; and, secondly, the methods of making contact in the electric
telegraph instruments, technically known as relays or repeaters.
In witness whereof, I, the said Sir Charles Tilston Bright, have hereunto set
my hand and seal, this Twenty second day of August, in the year of our
Lord One thousand eight hundred and seventy nine.
CHARLES T BRIGHT