IMPROVEMENTS IN
Year: 1880

page_text: LETTERS PATENT to Sir Charles Tilston Bright, of 20, Bolton Gardens, in the
County of Middlesex, Knight, for an Invention of "IMPROVEMENTS IN
PROVISIONAL SPECIFICATION left by the said Sir Charles Tilston Bright
at the Office of the Commissioners of Patents on the 12th June 1880.
Sir CHARLES TILSTON BRIGHT, of 20, Bolton Gardens, in the County of
Middlesex, Knight. "IMPROVEMENTS IN ELECTRIC TELEGRAPHS AND IN APPARATUS
CONNECTED THEREWITH."
My Invention consists of improvements in the receiving apparatus of electric
telegraphs and other instruments employed for signalling by electricity, whereby
the action of the moving parts is rendered more distinct and the electromotive
force requisite to produce a signal is much reduced.
In the first part of my Invention I construct an improved acoustic and indicating
telegraph, in which one of the poles of a polarised electromagnetic coil is placed
opposite to one of the poles of another electromagnetic coil, the polarity of the two
poles being the same.
The distance of the poles from each other is regulated by means of a screw
adjustment.
The free end of a movable soft iron tongue or arm, which is polarised with an
opposite polarity to that of the two electromagnetic poles, lies between them.
The other end of the tongue is supported upon pivots.
A lever, which I prefer to make of aluminium for the sake of lightness, is
extended from the pivotted end of the tongue on the other side of and in the same
plane with it.
The length of the lever is greater than that of the tongue, so that the application
of force at the end of the lever has through its greater distance from the axis or
fulcrum a leverage or mechanical advantage over the end of the tongue at the point
where it is adjacent to the poles of the electro-magnetic coils. For ordinary
telegraphic purposes I make the length of the lever about four inches, and that of
the tongue one inch.
The end of the lever is connected by a link of aluminium or other metal or by
a thread to the end of a small movable arm carrying an adjustable weight, by

page_text: which the lever is retained in its place of rest when no current is passing through
the coils, or an adjustable spring may be used instead of a weighted arm.
At a point in a line with the lever, and about midway or a little less between
its axis and its end, a light axle is pivotted in the same plane as the axle of the
tongue and lever, one end of which passes through the dial plate of the instrument
and carries a light external indicating needle or pointer, and the other end carrios
inside of the dial plate a short slotted arm which is engaged by a pin projecting
from the lever.
At another point in the lever (which may be about the same distance from the
fulcrum as the length of the tongue) a hammer is fixed to it, and the weight of the
hammer and that of the lever should balance the tongue.
A sounder, which may be a reed of motal, or a bell, or a plate of glass, as used
in my former acoustic telegraph instruments, is placed on each side of the hammer,
and the sounders serve as stops to limit the motion of the lever and consequently
of the indicator.
The sounders can be adjusted so that either of them may be placed nearer to or
further from the hammer, or so that the hammer is in contact with one of them
when at rest. Thus when they are both placed at an equal distance from the
hammer the alphabet which is expressed by beats of an indicator both to the right
and to the left may be used; or when one sounder is placed against the hammer,
so that it is in contact with it when the lever is at rest, or zero, and the other is
placed a short distance from it, the alphabet which is expressed by dots and dashes
(as used in the ordinary recording instrument) may be used, the signals in both
cases being given to the eye and to the car at the same time.
In this part of my improvements I also use a sounder fixed to the lever in place
of the hammer, and limit its motion by two sounders or stops which are
adjustable.
The details of the above described improvements may be varied in different
ways, as, for example, the polarised electromagnetic coils may be moved bodily by
a screw adjustment; or pole-pieces screwed into or upon the ends of the soft iron
cores of the electromagnetic coils may be used, or the pole-pieces may slide in the
ends of the cores and be moved by a screw adjustment; or the long lever instead of
being on the opposite side of the axle of the polarised tongue may be a continuation
of the latter, the hammer (or sounder) being in this case placed on the other side to
balance the tongue and lever; or the long lever may be used to give visual signals
directly to the eye, discarding the detached indicator, which is of special use where
the operators are accustomed to the angular motion of the indicator of an ordinary
needle instrument.
I also use in place of the hammer a hollow sounder or reed, which strikes against
two other sounders or two adjustable stops.
My improvements may be applied to the telegraph instrument known as a relay
for recording signals, or for repeating to other circuits, or for duplex or quadruplex
working, without being used for acoustic or visual signalling, by substituting an
arm making contact with adjustable insulated studs for the hammer.
Another part of my improvements consists in combining the long lever and the
other improvements herein before mentioned with the system of neutralising the
effect of a spring or weight during the passage of a current, which is set forth in
the Patent granted to me in the year 1879 numbered 792.
My improvements are specially applicable to instruments for railway and block
signalling for the protection of trains, owing to the distinctness of the beat of the
indicator and the loud sound made at the same time, by which attention is imme-
diately directed to the fact of the apparatus being at work. This particular feature
of my improvements is of great importance at railway stations and signalling boxes,
where signal levers are being worked or other noises are liable to interfere with
the attention directed to the telegraph instruments ordinarily in use.

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
9th December 1880.
Sir CHARLES TILSTON BRIGHT, of 20, Bolton Gardens, in the County of
Middlesex, Knight. "IMPROVEMENTS IN ELECTRIC TELEGRAPHS AND IN APPARATUS
CONNECTED THEREWITH."
An
My Invention consists of improvements in the receiving part of electric telegraph
instruments, and in other kindred apparatus for signalling by electricity, whereby
the action of the moving parts is rendered more distinct and the electromotive
force requisite to produce a signal of a definite strength is much reduced. The
first part of my improvements relates to the receiving part of instruments in
which signals are communicated to the person receiving telegraph messages by
way of the ear and also of the eye; in other words, to a combined indicating and
acoustic telegraph. At Fig. 1 is shown the back of the dial or screen of my
improved instrument, and at Fig. 2 a side elevation of the same partly in section,
the letters agreeing in both Figures where corresponding parts are shown. a, a', are
two electro magnetic coils fixed to b, the lower pole of a permanent magnet (the
middle of which is indicated by dotted lines), by which they are polarised;
c, c', are the upper poles of the coils, and the soft iron pole pieces d, d', pass through
the poles, into which they are screwed, and their distance from each other can be
regulated by means of adjusting keys applied to the brass square ends e, e¹. The
adjustment by this means is very delicate, and the polarisation is very perfect,
owing to the intimate contact of the screw threads throughout the surfaces.
opening in the outer case of the instrument opposite to the square ends enables
any adjustment to be made by the keys without removing the case, as shown, by
the key at el passing through a hole in the side of the case, which is represented
in section. is the free end of a movable soft iron armature or tongue, which is
polarised by g, g¹, the upper pole of the magnet b, g, and has therefore an opposite
polarity to that of the poles d, d¹, between which it lies. The other end of
the tongue is supported upon pivots in a slot cut in the pole of the magnet
between g, g. A lever h, h', which I prefer to make of aluminium for the sake of
lightness, is extended from the axis of the tongue on the upper side of and in the
same plane with it. The length of the lever is greater than that of the tongue, so
that the application of force at its end has through its greater distance from the
axis or fulcrum a leverage or mechanical advantage over the end of the tongue at
the point where it is opposite the poles d, d. The end of the lever is connected
by a link of aluminium or other metal (or which may be a thread or a piece of
fine gut line, such as is used by anglers) to the end of a small movable lever or
arm j, which is mounted on centres, as shown, and carries an adjustable weight k.
By the action of the weight through upon the lever the latter is retained in its
place of rest or zero when no current is passing through a, a. A spring may be
used in place of the weighted arm, but it is not so steady in its action upon the
indicating needle described below. is a light pivotted arm resting upon two
pins m, m³, standing out from a small plate fixed upon the tongue near to its axis,
by which any vibration of the tongue and lever at the end of a beat or signal is
checked. At a point in a line with the lever, about a third part of the distance
between its axis and end, a light axle is pivotted in the same plane as the axis of
the tongue, one end of which passes through the dial plate n, n, and carries a light
external indicating pointer or needle o, o, and the other end inside the dial carries
a short arm p, p, which is slotted or forked at its upper end, and is engaged by a
ping projecting from the lever. At another point in the lever about as far from
its fulcrum as the length of the tongue the hammer is fixed. Two sounders 8, 8¹,

page_text: to be further described hereafter, are fixed by means of the steel plates t, t, and
studs u, u, to the back of the dia! plate, and the sounders serve as stops to limit
the motion of the hammer and lever and of the needle outside the dial. At Figs. 3
aud 4 are shown back and side views of the detached needle or indicator o, o, with
its slotted or forked arm p and the pin q, which projects from the lever h, h, i
Figs. 1 and 2, and moves the needle to the right or left as the current through a, a',
is positive or negative. v, v, Fig. 1, are perforations in the dial, through which
the sound is emitted, or through which the mouths of the sounders protrude. At
Fig. 5 is shown the front of the dial n, n, (Figs. 1 and 2) o, o, being the needle;
8, 8, are the mouths or outer ends of two flat shaped tubes or sounders, corresponding
to the parts indicated by the same letters in Figs. 1 and 2, which enter into or are
immediately opposite, and close to but not touching the sides of v, v, the two
perforations, which are similar in shape to but a little larger than the mouths of the
sounders. w is an opening in the dial to facilitate the adjustment of d, d¹, Fig. 1;
x, x, are two small circular plates of ivory let into the dial, corresponding
to the stops or pins of the ordinary needle instrument, but which are really
false stops or indicating points, as the needle is not stopped against them, their
surfaces being flush or nearly so with the dial. Upon the dial the letters
of the alphabet and signs representing the beats to each side by which the
letters are expressed are painted, as shown in the Figure. I prefer the front of the
dial to be black in colour, the needle white, and the lettering pale green, an
arrangement which renders the visual signals very distinct to the operator. At
Fig. 6 is shown a side view of one of the sounders, y being the outer or exposed
end or mouth which is open, and the end inside the dial or screen which is
closed, and is fixed to t the metal plate by which it is fastened to the stud u, in
Figs. 1 and 2. n, n¹, show a section of part of the dial plate. The sounders may
be made of thin brass, German silver, or other suitable metal. It is desirable that
there should be an appreciable difference in the tone emitted from each of them,
which can be attained by making them of different materials, but I find the
difference is rendered more marked and more easy to reproduce in the same degree
in different instruments by altering the size of one of them, so as to vary the size
or shape of the hollow chamber, as shown in side view at Fig. 7, where the
mouth y is of the same size as the mouth y in Fig. 6, but the inner or closed end z
is enlarged, as shown, and by this means a lower note is produced. The width
between the sides is the same throughout. I have shown the hollow sounders in
the shape which I find suitable, but they may be constructed of some other form,
e.g., circular or square, provided they are hollow and closed at one end and open at
the other. In such case the perforations in the dial or screen are shaped to suit the
configuration of the sounders, and so also in case of sounders of any other form
being used, as for example, if a plate of metal or glass is employed, the perforation
or opening would take the form of an oblong slot. I also use a sounder fixed to
the lever in place of the hammer, and I limit its motion by two other sounders, as
shown at Fig. 8, in which a is the side of the movable sounder, and b, c, the fixed
sounders; or the movable sounder may be limited in its motion by adjustable
stops, as shown at Fig. 13, to be described hereafter. The improved receiving
instrument, which I have shown in its complete form at Figs. 1, 2, and 5, and as to
some of its parts at Figs. 3, 4, 6, and 7, is more powerful than any of the
instruments now in use in which signals are made to both sides of zero, either
visually or direct to the ear, except by the aid of a relay and local battery. The
electrical force necessary to work it is comparatively small, and I estimate that
three fourths of the battery power employed for working needle instruments might
be saved if it were generally used. With an ordinary Leclanché battery of 10 cells
readable signals may be obtained, if the instrument is in proper condition, through
20,000 ohms. resistance, and good audible signals through 12,000 ohms. In cases
where it is necessary to place the instruments or to make them interchangeable
with the ordinary instruments, it is better to fix the yoke of the coils to a brass
bracket instead of to the permanent magnet b. In carrying out the details of my

page_text: Invention, the shape and position of the different parts may be altered in various
ways, as, for example, the polarised electro magnetic coils may be moved bodily by
a screw adjustment, as is shown at Fig. 10, or the pole pieces may slide in the ends
of the cores and be moved by a screw adjustment, or the long lever in place of
being fixed, as shown, may be fixed to the tongue at its free end, as is shown at
Fig. 13, the hammer or sounder being placed on the opposite side of the axle, or
the axle of the tongue may be extended so as to pass through the dial and carry
an external needle, discarding the detached needle, which is of the greatest use
where the operators are accustomed to the comparatively large angular motion of
the pointer of the ordinary needle instrument. I also construct the cores of the
electro magnetic coils of broad plates of soft iron, so that the flanges are of an
oblong form similar to those of an ordinary galvanometer. At Fig. 9 a shows the
top of this coil, and bits pole piece fixed to its oblong soft iron core. Fig. 10
shows a front view of two of the coils marked a, a¹; b, b¹, represent one side of the
pole pieces, and c the front of the polarised tongue; d is the permanent magnet by
which it is polarised, and e, e¹, hinges attaching the lower end of the cores of the
coils to f, the other pole of the magnet. At y is a spring fastened at one end to the
frame of the instrument, and at the other to an eye projecting from the upper pole
of a, by which a is pressed against a stop h adjustable by a screw, so that the pole b
can be advanced or withdrawn to or from the tongue, and in like manner b¹ can be
regulated by means of its screw and spring. A spring is shown in connexion with
the lever in place of a weight, as in Figs. 1 and 2. At Fig. 11 is shown a side view
of the induced tongue d, the lower end of which presents the whole of its breadth
to the broad poles of the coils, an arrangement of great force and utility, not only
in direct-acting sound instruments but in relays when long circuits are worked, in
which case the moving parts should be lighter. At Fig. 12 is shown the front of a
visual and aural telegraph, in which absolutely dead beats of the needle between
zero and the two points or false stops x, x¹, Fig. 5, are obtained free from any
vibration or tremor whatever, while the successive beats can be repeated much more
rapidly than is possible with any of the indicating instruments now used. a, a¹, in
Fig. 12, are the ends of two electro-magnetic coils, b being part of the yoke joining
their cores together at the other ends; the poles of the coils are enlarged, as shown
at c, c¹, so that they each carry two pole-pièces, d, d, d¹, d¹, which can be regulated
by means of the capstan holes and screw threads shown in the Drawing; but after
the instrument has once been properly adjusted little or no alteration will be
required. e, e¹, are the poles of a permanent magnet, and f, f, f¹, f', are two
armatures or tongues pivotted therein, and therefore having an opposite induced
polarity, both ends of f,f, being (say), north, and of f', f¹, south. g,g, are two stops,
against which f, f¹, rest when no current is passing through the coils. Two small
pads of leather or caoutchouc are shown on f, f', to prevent any confusion in the
signals arising from the sound which would otherwise be emitted on the tongues
returning to the stops. h, h are two sounders, which I prefer to be of the form
described before and shown at Figs. 6 and 7. i is a plate fixed upon the axle of
the external needle corresponding to the arın, p, in Figs. 1, 2, 3, and 4, but of a
Tshape. The needle and dial are not shown in Fig. 12 to make the description
more clear, and they do not differ from the same parts in Figs. 3, 4, and 5. j, j¹, are
two arms projecting from ff ff, the ends of which lie close to i. Upon a
current being sent through a, a so as to make c north in polarity and c south,
then, assuming the polarity ascribed above to f.f, its upper end will be repelled by c
and its lower end attracted by c¹, the arm j will at the same time lift the upper
left hand limb of i, and the detached needle on the same axle as i will be deflected.
On the current ceasing the needle will be brought back to its exact position at zero
by pressing the lower limb of i into its central place; if a contrary current is
sent f¹, facts in the same manner. Another part of my improvements has
reference to apparatus applicable to the Morse" alphabet, in which letters are
expressed by variations of short and long signals. At Fig. 13, a, a', show the front
of two electro-magnetic coils united by a yoke and fixed to b, one of the poles of a
"

page_text: permanent magnet. c, c¹, are the poles, c, d, the pole pieces, and e, e¹, the square
ends for regulation as described in previous Figures. f is the movable armature or
tongue polarised by g, g, the other end of the permanent magnet. h is the lever
and i a sounder, which should balance the weight of f and h. j, k, are two stops
with a screw adjustment, which are insulated by ebonite plates l, m, so that the
instrument may be used as a relay as well as a direct working acoustic instrument.
Two sounders may be substituted for j, k, according to the arrangement shown at
Fig. 8, and the instrument may be used as a Morse sounder or with the Steinheil
code by changing the position of the stops or sounders. The stops are mounted in
the Figure upon a thin metallic plate n, n, which has a slot in it for the arm
carrying to pass through; n, n is fixed to the magnet, which is planted upon the
base plate o, o. PP, P, are three feet or supports fixed to o, o, and standing upon
9, 9, a sounding board made of thin wood. ,, show in section an outer tube
which fits over n, n, and a flange 8, 8, upon o, o, forming the outer case of the
instrument. The oblong shaped coils and shutter shaped armature or tongue, shown
at Figs. 9, 10, and 11, may be used with advantage where the conditions of the
circuit warrant the cost and additional resistance entailed thereby. This instru-
ment may be used without the lever, h, although not with such good effect, as the
tongue cannot be employed so nearly in the centre of the magnetic field, by
regulating the position of the sounders or stops and the pole-pieces, or the poles
of the coils if the oblong coils are used, so that upon the cessation of the
current the pole on the side from which the tongue moves (when the
current flows) shall have a greater attraction for the tongue than that of
the opposite pole, and thus bring back the tongue towards it. I wish it to
be understood that I do not claim the use of the apparatus described in reference
to this Figure if used as a relay only without the lever, but I claim it either with
or without the lever in combination with sounders or acoustic appliances for
reading by sound. Another part of my improvements, consists in employing this
apparatus in combination with a sending key, by which reverse currents are sent,
that is to say, a current in one direction when the key is depressed, aud in the
other when it returns to its position of rest, by which means the polarised tongue
is moved backwards and forwards, and in this arrangement very little tension of
the spring is requisite, or the lever and spring may be dispensed with. At Fig. 14
is shown the plan, at Fig. 15 a front elevation, and at Fig. 16 a side elevation of
another part of my improvements, which is applicable either as a relay or sounder,
or both together, but which is only adapted for use with the "Morse" alphabet. In
these Figures a, a', are the electro magnetic coils, and ba magnet by which they
are polarised. c, c, d, d', and e, e¹, represent their poles, pole-pieces, and adjusting
ends, as in previous Figures. f, f', are two soft iron armatures or tongues pivotted in
and polarised by g, g, g, g, a permanent magnet. h, h, h, is the lever fixed to the
tongues ff is a sounder against which a pin or hammer projecting from his
stopped when a current is passed through a, a'. is an adjustable stop, and land m
the spring and adjustment supported by the bracket n. The base plate o, o, is
supported, as in the previous Figure, by three feet p, p, p, which rest on the
sounding board q, q; the sounding board is made of thin wood, and I prefer that it
should form part of a box or screen open in the front, as represented in section
by in Fig. 16. Another part of my improvements consists in combining the lever
and other improvements hereinbefore set forth with the system of neutralising the
effect of a spring or weight during the passage of the current described in my
Patent, No. 792, of the year 1879, and in doing this I cause the armature therein
shown as slackening or withdrawing altogether the effect of a weight or spring, to
act in the place of the weight & in Figs. 1 and 2, by reversing the position of the
long lever hand placing it below the axle of the induced tongue, as shown in the
instruments drawn at Figs. 10 and 13, by which the armature being placed upon a
lever under the lower ends of the coils can be conveniently connected by a link to
the lower end of the lever, thus acting in the same manner as the weight / in Fig. 1,
to bring back the lever to zero. Upon a current passing, whether positive or

page_text: negative, it is lifted, thus leaving the polarised tongue free to move on either side. Or
the soft iron armature may reduce or withdraw the tension of a spring, or it may lift a
connecting arm, such as is shown at l, m, Figs. 1 and 2, or a light plate carried upon
a vertical shaft, or other mechanical equivalent for the same purpose of assisting in
bringing back the polarised tongue to zero. My improvements are specially
applicable to instruments for railway and block signalling purposes, owing to the
distinctness of the beat of the indicator, and the loud sound emitted at the same
time, by which the attention of the operator is called, a feature of my improvements
which is of considerable importance at railway stations, where the clerk is
principally engaged in other duties than that of working the telegraph instrument.
Having thus described the nature of my Invention, and the means by 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 improvements, as
various modifications thereof may be devised, but what I claim and desire to be
secured to me by the herein in part recited Letters Patent are,―
Firstly. The lever h shown in Figs. 1 and 2 and elsewhere in the Drawing
appended hereto, and the combination thereof with a polarised armature or tongue,
and an electro-magnet having adjustable poles.
Secondly. The screw adjustment of the pole pieces of an electro-magnet, as shown
at Fig. 1 and elsewhere in the Drawing, and the combination thereof with a polarised
armature or tongue.
Thirdly. The detached indicating pointer or needle shown at Figs. 3 and 4 and
elsewhere in the Drawing, in combination with a polarised tongue and sounders, or
either of them.
Fourthly. The fixed sounders shown at Figs. 6 and 7 and elsewhere in the
Drawing, and the movable sounders shown at Figs. 8 and 13.
Fifthly. The arm shown at Figs. 1 and 2, by which the moving part of a
receiving instrument is retained at zero, and assisted in returning thereunto, either
when used alone or in combination with the lever referred to in my first claim.
Sixthly. The combination of two polarised armatures or tongues with a detached
indicator shown at Fig. 12, which is moved by them to one or the other side,
accordingly as the current transmitted by them is positive or negative.
Seventhly. The combination of an electro-magnet having two adjustable poles
with a polarised armature or tongue, and a sounder or sounders.
Eighthly. The combination of two electro-magnetic coils, the cores of which are
polarised by a permanent magnet with a polarised tongue or tongues, and a sounder
or sounders.
Ninthly. The lever j, Figs. 1 and 2, and the weight k.
Tenthly. The employment in combination with sounders of a dial or front plate
upon which the letters of the alphabet and the signals corresponding thereto are
inscribed, as shown at Fig. 5.
Eleventhly. The coils and radial screw adjustment shown at Fig. 10, combined
with a polarised tongue.
Twelfthly. The combination of a polarised armature or tongue with an electro
magnet and a sounding board, shown at Figs. 13, 15, and 16.
Thirteenthly. The casing r, Fig. 13, in combination with an electro-magnet and a
sounder or sounders.
Fourteenthly. The combination of a relay and direct-acting sounding instrument.
Fifteenthly. The employment of perforations in the dial or case of a telegraph
instrument in combination with sounders either wholly or partly inside the case,
and with an external indicator or needle, by which visual signals are shown
coincidently with the acoustic signals emitted from the sounders.
Sixteenthly. The false stops or indicating points x, x¹, Fig 5, in combination with
sounders.
Seventeenthly. The combination of sounders with openings in the outer frame
or case, and external adjusting studs or keys for regulating either or both of the
poles of an electro-magnet, as shown at el, Fig. 1.

page_text: Eighteenthly. The perforation w, Fig. 5, for facilitating the regulation of the
poles of an electro magnet inside the dial or case, in combination with an indicating
needle and sounders.
Ninteenthly. The employment of a reversing key in combination with a
polarised armature or tongue and acoustic appliances, as described in reference to
Fig. 13.
In witness whereof, I, the said Sir Charles Tilston Bright, have hereunto set
my hand and seal, this Sixth day of December, in the year of our Lord
One thousand eight hundred and eighty.
DDTANA
CHARLES T. BRIGHT. (L.S.)