IMPROVEMENTS IN ARC ELECTRIC LAMPS
Year: 1882

page_text: PROVISIONAL SPECIFICATION left by the said Francis Murray Rogers at the
Office of the Commissioners of Patents on the 7th July 1882.
FRANCIS MURRAY ROGERS, Electrician 21 Finsbury Pavt E.C. IMPROVEMENTS
IN ARC ELECTRIC LAMPS
My Invention, consists in an improved method of regulating or controlling, Arc
Electric lamps; For this purpose I employ a solenoid or an Electro magnet, so
arranged as that the rod carrying the upper carbon, shall pass through the centre of
the solenoid, or between the two bobbins of the electro magnet, or I employ two
solenoids, arranged in a similar manner to the electro magnets, with the rod passing
between them. The solenoid has a sufficiently large central hole, to allow the core
which is hollow to move freely up and down within it, the central rod carrying
the upper carbon passing through the hollow core sliding within the solenoid, and
the centre of the lamp body. Attached to and forming part of the hollow core, and
extending downwards towards the base, or floor, of the lamp, is a clipping arrange-
ment, consisting of a block of any suitable metal, divided or separated centrally in
the direction of its length, to one side, or diagonally. This block is clamped
together, and carefully bored so as to exactly fit the sliding rod, which passes
through it, and the hollow core. The opposite half to that forming part of, or
securely fastened to the sliding core, is loosely secured (by 2, or 4, or more links,
parallel to each other) to that forming part of the core, so that it can move freely
up and down in a line parallel with the rod, and the other half to which it is
attached by the links. It's weight causes it to embrace the sliding rod tightly,
and the loose half is made to hang a little lower than that fixed to the hollow core,
so that it shall be lifted upwards, and liberate the rod when it touches the floor or
base of the lamp. Upon a current flowing round the solenoid or electro magnet,
the core is sucked into the solenoid or the armature to which the clip is attached,
is drawn towards, the solid cores of the electro magnet. The loose half firmly clips

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the rod, and carries it upward establishing the arc, which is regulated by a screw.
fixed in the base of the half-block forming part of the core, and passing through
the base of the lamp, so as to control the rise and fall of the block. When my.
lamp is used in series, I provide an arrangement whereby each lamp is made to
act independently of any others working with it, and is automatically cut out
should its resistance become too great or should it fail from any similar cause,
the current being shunted past the lamp to the others in circuit
This arrangement is as follows.—
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Fitted to some convenient part of the lamp or detached and separate from it, is
a peculiar form of compound magnet, one half being of steel, and permanently
magnetized, and the other half being made of iron, or some similar magnetizeable
metal, the permanent magnet is surrounded with a coil of fine wire, connected with
the main circuit, and so wound as to permit under the ordinary working conditions
of the lamp governed by this arrangement, only a small current to pass in such a
direction as to depolarize or weaken its action. Pivoted to a central axis, or
hinged, at one end is a small bar magnet, coated on one side with some good
conducting metal, the poles of this bar magnet are so arranged with regard to the
permanent magnet as that opposite poles shall face each other, and when in position
the end nearest to the permanent magnet is attracted by it, and held against it, so
breaking the main current in which it acts as an automatic switch. Should however
the resistance of the arc become too great, more current flows through the fine wire
coil, until the permanent magnet has its polarity reversed, the end of the bar
magnet, facing it, is thus repelled, and making contact with a suitable stop, the
main current travels along the conducting strips and round a few turns of thick
wire upon the iron core forming the other half of the compound magnet, which is-
so wound as then to become an electro magnet of polarity opposite to that of the
magnetized bar opposed to it. In this way the current is diverted from the
lamp.
If desired a horseshoe permanent magnet may be used.-in place of the
compound one described

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Francis Murray Rogers in the Great Seal Patent Office on the
6th January 1883.
FRANCIS MURRAY ROGERS Electrician 21 Finsbury Pavement London, E.C
IMPROVEMENTS IN ARC ELECTRIC LAMPS
My Invention consists, in an improved method of regulating, or controlling Are
Electric Lamps. For this purpose, I employ a solenoid, or an electro magnet, so
arranged as that the rod carrying the upper carbon shall pass through the centre
of the solenoid, or between the two bobbins of the electro magnet, or I employ two
solenoids, the rod carrying the upper carbon passing between them, as in the case
of the electro magnets. The Solenoid has a sufficiently large central hole to allow
the core which is hollow, and may be of cast or wrought iron, to move freely up and
down within it, the central rod carrying the upper carbon passing through the
hollow core, sliding within the solenoid and the centre of the lamp body. Attached
to, or forming part of the hollow core, and extending downwards into the base, or
part of the lamp under the solenoid, is a clip arrangement consisting of a block of
suitable metal divided lengthwise, centrally, to one side, or diagonally, this block
is clamped together and carefully bored so as to exactly fit the sliding rod, which
passes through it and the hollow core. The opposite half to that secured to, or
forming part of the hollow core, is loosely held by two, or four, or more links
(parallel to each other) to that forming part of the core, so that it can move freely
up, and down, in a line parallel with the rod which it embraces, and the other
part which is attached to, or forms part of the hollow core. The weight of this
loose half enables it to embrace the rod tightly, and it is so fixed as that when
embracing the rod it shall hang a little lower than the part to which it is attached;
and be lifted upwards and release the rod as soon as it touches the floor of the
lamp. When a current flows round the solenoid or electro magnet, the core is
sucked into the solenoid, or the armature to which the clip is attached is drawn
towards the magnet, the loose half of the clip drags behind, and binds against the
rod, which is carried upwards establishing the arc, the length of which can be.
regulated by a screw cut upon the end of the core, which is made to protrude
through the plate forming the base of the lamp for this purpose, or a screw can be
inserted in the base of the half block forming the core, and passing through the
plate forming the floor of the lamp. Provided the lamp is used singly, no other
regulation is needed to maintain a steady light sufficient for general purposes.
But as great steadiness is required for some purposes, by slight modifications my.
method of controlling the descent of the upper carbon, can be adapted to effect
this end in the way and manner hereafter described. When used in series, I use
a special form of independent control, by which each lamp is regulated inde-
pendently of any others, that may be in the same circuit, and in the event of the
rod sticking, or the resistance of any particular lamp becoming too great, it is
automatically cut out, and the current shunted past the lamp to the others in
the series. I will now proceed by means of the drawing to describe my invention
more particularly, similar letters of reference are used for similar parts in all the
figures.
Fig 1 and Fig 2, Shew in part section and elevation my improved method of
regulating that class of Arc Electric Lamp, in which the arc is maintained by the
gradual descent of the upper carbon. A Fig 1, and Fig 2, is the solenoid, or the
electro magnets, wound preferably with thick insulated wire of say 12, or 14, wire
gauge. B is the wrought or cast iron core, or if electro. magnets are used as in‘

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Fig 2, the armature. Attached to either the core, or armature, in any convenient
manner or cast or forged in one piece with it, and extending downwards towards
the base or floor of the lamp and when necessary passing through it, is a
clipping arrangement C, consisting of a block or rectangular piece of metal,
divided or separated lengthwise, at its centre line, to one side or diagonally.
This block, which is made in halves is clamped together, and in order that it
may when bored exactly fit the rod, a thin slip of metal such as brass, or iron,
is placed between the halves, and then after clamping or sweating the halves
together, the block and core are carefully bored out, to the exact size of the rod
intended to be used. After boring the rectangular block, is filed or shaped up
square on the faces parallel to each other, and the core and nose piece of
which, half of it may form part, or to which the rectangular piece is fitted, is
carefully turned, and made to slide easily within the hole F, in the solenoid,
Fig 1, or if an armature and electro magnet, be used as in Fig 2, the
arinature is drilled, and made to slide upon the two pins, F, F, which act as guides
Two or Four or more links D, D, are now made and fitted by means of screws to
each side of the two halves of the block. After they are placed in their proper
position parallel to each other the screws are removed, and the thin piece of metal
taken out, the balf block is then re united as before, and so fastened as to be quite
free to move up and down parallel with its counterpart which is attached to or
forms part of the core, and nose piece, Figs 4, and 6, shew this clip full size and
will make its construction quite clear. Upon a current entering the lamp at G, the
opposite terminal H, being connected up so as to complete the circuit with the
machine the solenoid or electro magnet is excited sucking up the core, or attracting
the armature B the loose half of the block C dropping by gravity to the position
shewn in Fig 6; the rod I is tightly embraced and lifted up thereby separating the
carbons and establishing the Arc As the carbons burn away, the resistance to the
current entering at G, and flowing round the solenoid, or electromagnet increases,
and the core in the case of the solenoid gradually drops, until the loose half of the
block C, which when gripping the rod hangs lower than the part to which it is
attached, touches the plate, or floor E the rod is then released and slides slowly
through the block, shortening the arc, and as more current then flows round the
solenoid, or electro magnet, its length is adjusted. The movements described, are
effected so rapidly as to be almost imperceptable, and as the rod is held rigidly and
the release takes place gradually the half block acting as a species of brake, the
blinking and jumping, peculiar to arc lamps regulated by a ring or washer, is
avoided, while the rod is always smooth, and unscored. The nose-piece K, which in
Figs 1. 2. 5. 6 is shewn as part of the core, extending through the plate, is screwed
to receive the nut J, and the travel of the core or armature can be regulated to
strike the arc, of any desired length. Fig 3, shews my method of regulating shunt 4
lamps, or that class of lamp in which the carbons being separated by a weight, or
spring, are brought together, and the length of are regulated by a solenoid A, of high
resistance, connected up to the circuit as a shunt; The main current going through
the carbons. The core B is made to fit the tube of the solenoid, and the clip and
nose piece are carried up through the top plate of the lamp, being held there by a 4
spring inserted inside the solenoid, or by the weight and lever as shewn, or by a
small volute spring regulated by a nut, these various methods of separating the
carbons, by springs or counter balance being shewn by letters L. The action of the
clip in this case, is the reverse of that hitherto described. When the core B is drawn
in to the solenoid, the loose half of clip, C' touches the top of the bobbin of the 5
solenoid, the carbons come together, and the current in the shunt solenoid A being
lessened the arc is formed, by the spring or counterbalance, Fig 5, Shews a
gripping block made wedge shaped, the links being dispensed with and the loose
half being guided by two rollers M, M, and spring, its action is identical with the
block just described, but it is suited for large lamps carrying heavy carbons. Fig 6 5
and Fig 7, Shew two views of the gripping block. In Fig 6 the block is cut
diagonally the links being placed at right angles, to the diagonal line, or they can

page_text: be placed at any other suitable angle, Fig 7 shews a side view of the block; the
ends of the links D, being shewn and a peculiar method of adjusting the core of the
solenoid, to the best position for obtaining the greatest lifting power; A sleeve O
carrying a table, upon which the block C rests, is screwed into the base of the lamp,.
the nose piece end of the core K, is made to pass through this sleeve, and can
be adjusted by the nut J. By screwing the sleeve O up or down, the core B can be
made to slide any distance, into the solenoid.
'
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Fig 8 Shews my improved method of regulating are lamps, where great
steadiness is required A is the main solenoid, and round this, the current flows to
the carbons, which are separated by means of the clip, in the manner already
described. One of the links D of the clip C is prolonged, and at its end is pivoted
to an iron core, dipping into a solenoid, which however may be replaced by an
electromagnet, with an armature. This solenoid or electro magnet N, is wound to a
very high resistance, and is connected to the two lamp terminals, as a shunt, to the
main circuit, on the floor of the lamp is shewn a small cut out, which consists of a
spring P, connected to the fine wire of the shunt coil, through the bridge Q. When
the lamp is out of action, the clip block is made to press on the spring P, forcing it
away from the bridge Q, and so cutting out the shunt solenoid or electro magnet.
Upon a current flowing round the. main coil A, the core B is drawn up and the
spring follows it, until it touches the bridge, when the shunt coil comes into action
It does not however operate the loose side of the clip block C, at once but when
the arc lengthens sufficiently the power of the shunted solenoid, or electro magnet,
becomes great enough to slightly raise the loose half of block C¹ by means of the
lever D the rod carrying the carbon is thus lowered as by a brake action, and no
jumping, or blinking, is observed, when the parts are properly adjusted. This same
action can be applied to the shunt. lamp previously described, the core and rod
being upheld by a spring, or counterbalance, and the loose half of the block
operated by a solenoid or electro magnet in a shunt circuit, so as to obtain the
sliding action of the rod by using the loose half of the block as a brake. The cut-
out is used to avoid the waste of current common in lamps of the shunt type, or in
which shunted coils are used. Considerable latitude may be given to the spring
cutout, so that it would be quite possible to use a lamp so made without employing
the shunt coil, and when working properly the shunt is only taking current when
the arc is too long.
Fig 9, Shews my method of regulation for Arc Electric Lamps, where a main and
shunted coil is used on the differential principle. Should the arc become too long the
shunted coil N pulls down the core B, and the loose half of the block being lifted
by striking the top of the bobbin, the rod slides through, and the arc is thereby
regulated
Fig 10. Shews my method of controlling lamps worked in series. It consists of a
form of compound magnet one coil N, has a core of hard steel permanently magnetized,
and this coil is so wound with fine wire, connected as a shunt, to the lamp terminals,
that a current passing through it, will first depolarize it, and then reverse its
polarity. Pivoted to a central axis or hinged at one end is a small bar magnet,
coated on the side facing the magnets with some good conducting metal. The
poles of this bar magnet y are so arranged with regard to the permanent magnet, as
that opposite poles shall face each other, and when in position the end of the bar
magnet is attracted by the permanent magnet N and held against it. The bar
magnet y is connected at its centre, with the main leading wire from one terminal,
and when in its normal position, the circuit is made complete through the arc.
Should however the resistance of the lamp become too great the shunted coil N
receives more current until the permanent magnet, which forms its core has its
polarity reversed. The bar magnet y is then repelled, and striking the contact pins,
shewn on the other electro magnet S a. current is sent through the thick wire
surrounding its iron core which becoming a powerful electro magnet, holds fast the
bar magnet, and cuts off the current from the lamp. A Horse shoe permanent
magnet can be used in place of this arrangement if desired
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Fig 11. Shews another method of regulating a shunt lamp, the upper or positive
carbon is fixed to a frame E as shewn and the rod carrying the lower or negative
carbon, passes through the high resistance bobbin A, and core and clip B and C. On
the floor of the lamp is shewn a pawl or species of ratchet X which is grooved out,
to fit the rod loosely. The action is as follows. When a current enters the high
resistance shunt bobbin (the carbons being separated) the core is sucked up, carrying
with it, the rod and bottom or carbon, until contact is made with the top or +
carbon, the main circuit being now established, the core and clip block fall; because
less current is flowing round the shunted-coil, the rod however, cannot fall to the
same extent, as the pawl X jambs against it. The length of arc can be regulated
by altering the angle, at which the pawl X jambs the rod, a slot, or spring, being
made in, or fixed to the plate for this purpose. No springs, levers, or any other force
than gravity, is used to separate the carbons in this method. An electro-magnet and
armature can replace the solenoid if desired; the arrangement being similar to that
shewn at Fig 2
Having now described my Invention, I would state that I do not confine myself
to the exact details shewn and described, as they can be varied to suit the require-
ments of of the various types of lamps referred to without departing from its essential
features I am aware that lamps are in use, in which one, or two solenoids, or
electro magnets are used operating rings or clutches, that shunt lamps in which the
carbons being separated, by levers or springs, are caused to meet, and the are formed,
by means of a shunt coil, and rings or clutches, also that such an arrangement can
be made with a differential lamp in which there is a coil in the main and shunt
circuit, All the methods however employed are open to the objection, that the rod is
released suddenly, which is the cause of the blinking and unsteadiness peculiar to
lamps so regulated. My object is to avoid this, by so forming my clipping gear as
that a brakeing action is exerted on the sliding rod by the loose half of the block,
which slides quietly through; as if lowered by a fly, and train of wheels, the rod
more over is always smooth and free from indentations. I claim
1st In an Arc Electric Lamp, the combination of a wrought, or cast iron core,
passing into a solenoid, and protruding through the plate forming the floor of the
lamp, the nose piece passing through the floor plate being screwed, and having a nut
thereon to regulate the travel, Such core having a clipping block, half of which
may be forged or cast in one piece with such core or nose piece, the loose half being
held to its counterpart, by two or four or more links and being free to move up,
and down and grip or release the rod, the loose half hanging below its counterpart,
so as to touch the floor plate, and release the rod. Substantially as shewn and
described
2nd. In an Arc Electric Lamp, arranged with one or more electro magnets, in
the main circuit a core or sleeve forged or cast or attached to an armature, the rod
passing through the clip block, sleeve, and nose piece, substantially as described.
3rd. In an Arc Electric Lamp of the Shunt type, a core protruding through the
top plate, the other part of such core dipping into a solenoid, such core carrying the
clipping gear, or device for drawing down the rod, and releasing it, the carbons
being upheld by an internal or external spring, acting without the intervention
of any lever, directly upon the clip and core.
4th The combination with an iron core, and nose piece of a wedge shaped grip,
rollers guide and springs, substantially as described
5th The combination in an Arc. Electric Lamp, of an Iron core, and gripping
device, in which a "cut out" is used to avoid waste of current, in the shunt solenoid,
or electro magnet operating such gripping device, substantially as described in
Fig 8.
6th The combination in an Electric Lamp of arc type, of a metal sleeve sur-
mounted by a table such sleeve being screwed, and passing through the floor of
such lamp for the purpose of adjusting the position, of the iron core in the solenoid,
as described.
7th The combination in, or with an Arc Electric Lamp, of an automatic cut out,

page_text: composed of a compound magnet, the shunt or high resistance coil, being so wound
as to depolarize and then reverse the polarity of the permanent magnet, thereby
repeeling the permanently magnetized armature, which diverts the current from the
lamp in the way and manner described.
8th In an arc electric lamp, of the shunt type, the method of forming the arc,
and separating the carbons, the latter being separated by gravity, without the
aid of springs, weights, or levers substantially as shewn and described Fig 11.
In Witness whereof I the said Francis Murray Rogers Electrician &c. have
hereunto set my hand and seal this fifth day of January in the year of
our Lord 1883
Witness
C RICHARDSON.
21 Finsbury Pavement
E.C.
FRANCIS MURRAY ROGERS (L.S.)