IMPROVEMENTS IN ELECTRIC LAMPS
Year: 1882

page_text: LETTERS PATENT to James Grieve Lorrain of 2 Victoria Mansions in the
City of Westminster, Civil Engineer, for an Invention of "IMPROVEMENTS IN
ELECTRIC LAMPS
"
PROVISIONAL SPECIFICATION left by the said James Grieve Lorrain at
the Office of the Commissioners of Patents on the 27th July 1882.
JAMES GRIEVE LORRAIN of 2 Victoria Mansions in the City of Westminster,
Civil Engineer "IMPROVEMENTS IN ELECTRIC LAMPS
"
My Invention relates to improvements in that description of Electric lamps,
known as are lamps, and comprises various novel features hereinafter described,
whereby an electric arc lamp, of great simplicity and efficiency is obtained.
In carrying out the said invention I employ a moveable solenoid or sucking
magnet of high resistance, arranged as a shunt between the terminals of the lamp,
for releasing the upper carbon when from any cause the resistance of the electric
are becomes too great. I also employ the said solenoid, or sucking magnet for
separating the carbons to any fixed or determinate extent, and for striking the are
all as hereinafter described.
In order to effect these objects the various parts are constructed and arranged in
the following manner viz:
Within the solenoid or sucking magnet (which is arranged in a horizontal or
nearly horizontal position or at or about at right angles to the upper carbon) is
placed a core of soft iron (the said core forming in fact the core of the sucking
magnet) one end of which core is provided with a point, or points, or other suitable
device, which normally supports the upper carbon, whilst the other end (which may
be of brass or other suitable material) of the said core is provided with a spring or
other equivalent device capable of being regulated, for keeping one end of the core
in contact with the upper carbon, when not held back by the action of the current
in the solenoid or sucking magnet.
The solenoid or sucking magnet is pivotted in any suitable manner either at or
close to the centre, or at or close to one end, so as to be capable of swinging or

page_text: turning in a vertical plane, screwed bolts, or other equivalent devices, being suitably
combined and arranged so as to control or regulate the swinging movement. On
the solenoid or sucking magnet at or near one end thereof, a mass of soft iron is
fixed in any suitable manner; and above, or beneath it, according to which end the
above mentioned mass of iron is fixed, a second mass of soft iron is arranged in any
suitable manner and position. This second mass of soft iron, the purpose of which
will be hereinafter described, may be provided with a screw or other suitable
adjusting device for regulating its relative position to the mass of iron on the
solenoid or sucking magnet, or the height of the solenoid or sucking magnet above
this mass may be regulated whereby a similar result may be obtained
These devices operate in the following manner viz:
Assuming the lamp to be in operation, as the resistance of the arc increases more
of the current will pass through the solenoid or sucking magnet as a shunt, with-
drawing or sucking its iron core from the upper carbon and allowing the same to
descend by gravity, until as the carbons approach, the resistance of the arc is
reduced. At the same time the mass of soft iron on the solenoid or sucking magnet
is magnetised and tends to attract the mass of soft iron beneath it, but if this is
fixed the solenoid or sucking magnet itself turns or swings on its pivotted axis
through a small arc towards it. More of the current now passing through the arc
owing to its decreased resistance due to the carbons being nearer one another, less
passes through the solenoid or sucking magnet, which releases to a considerable
extent its core which is consequently pressed out against the upper carbon by means
of the spring or equivalent device above mentioned, and the solenoid or sucking
magnet is itself swung back into its normal position by means of a spring, or weight,
or other suitable device, attached in any suitable manner to the said solenoid or
sucking magnet and so raising the upper carbon and obtaining any desired length
of arc between the carbons according as the above mentioned adjusting screws
may be set.
Or, in lieu of the lower electrode remaining fixed as in the arrangement above
described, and the regulation being produced only by the lowering or raising of the
upper electrode, the regulation may be assisted by the movement of the lower
electrode which may be attached by an elbow shaped hinged lever, or other suitable
means, to the moveable solenoid, or sucking magnet, and so raised or lowered in
accordance with the movements of the latter.
Or, the solenoid or sucking magnet may be fixed and the piece of soft iron
secondly mentioned may be moveable, and produce the regulation of the are either
by being attached direct by suitable means to the lower electrode, or by means of
a clutch acting on the lower electrode.
Or the whole may be reversed as will be readily understood. For example the
solenoid or sucking magnet arrangement instead of regulating the descent of the
upper electrode, which tends to fall by gravitation, may be employed to regulate the
ascent of the lower electrode which may have a tendency to rise imparted to it by
means of a spring, or counterweight or other suitable device.
Should it be desired to arrange the carbons horizontally the same methods of
regulation may be employed by using the solenoid or sucking magnet arrangement
to regulate the length of the arc, the carbons being acted upon by a spring or
other equivalent device tending to bring them together. In this arrangement it
will be readily understood that one of the electrodes may remain fixed while the
other is acted upon for regulating purposes or both electrodes may be moveable
and so acted upon.
In order to aid in the support of the moveable electrode, or electrodes, and to
react against the pressure exerted by the core of the solenoid or sucking magnet,
upon the electrode or electrodes, Ĭ employ rollers or other suitable devices carried
by a frame which may either be the frame carrying the solenoid or sucking maguet
or an independent frame if found desirable.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said James Grieve Lorrain in the Great Seal Patent Office on the
27th January 1883.
JAMES GRIEVE LORRAIN of 2 Victoria Mansions in the City of Westminster
Civil Engineer IMPROVEMENTS IN ELECTRIC LAMPS
My said invention relates to improvements in that description of Electric Lamps
known as Arc Lamps and comprises various novel features hereinafter described
whereby an electric arc lamp of great simplicity and efficiency is obtained.
According to one mode of carrying out my said Invention I employ a movable
solenoid or sucking magnet arranged as a shunt between the terminals of the lamp
for releasing the upper carbon or electrode when from any cause the resistance of
the electric arc becomes too great and also for separating the carbons or electrodes
to any fixed or determinate extent and striking the arc.
In order to effect these objects the various parts are constructed and arranged in
the following manner viz
Within the solenoid or sucking magnet (which is arranged in a horizontal or
nearly horizontal position or at or about at right angles to the upper carbon) is
placed a core of soft iron (the said core forming in fact the core of the solenoid or
sucking magnet) one end of which core is provided with a point or points or other
suitable gripping device which normally supports the upper carbon, whilst the other
end (which may be of brass or other suitable non-magnetic material) of the said
core is provided with a spring or other equivalent device capable of being regulated
for keeping the pointed or gripping end of the said core in contact with the upper
carbon when not held back by the action of the current in the solenoid or sucking
magnet.
The solenoid or sucking magnet is pivotted in any convenient manner either at
or close to the centre or at or close to one end so as to be capable of swinging
or turning in a vertical plane, screwed bolts or other equivalent devices being
suitably combined and arranged so as to control or regulate the swinging
movement. On the solenoid or sucking magnet at or near one end thereof
I provide a mass of soft iron and above or beneath it (according to which end the
above mentioned mass of iron is placed) I fix a second mass of soft iron which is
rigidly supported in any convenient manner the effect of this arrangement being
that when the solenoid or sucking magnet is excited by the action of a sufficient
amount of current passing through it, the magnetic attraction will cause the
solenoid or sucking magnet to turn on its pivots towards the fixed mass of soft
iron at the same time that the pointed or gripping end of its core is withdrawn
from the upper carbon in readiness to lift the upper carbon to the requisite distance
by the return of the solenoid or sucking magnet to its normal position under the
action of a spring when the current passing through the solenoid or sucking
magnet is sufficiently reduced for the spring to predominate. It is obvious that as
an equivalent arrangement in lieu of the mass of soft iron first mentioned being
fixed on the body of the solenoid or sucking magnet it may be formed on or
attached to its core at or near the outer end thereof. The second mass of soft iron
may be provided with a screw or other suitable adjusting device for regulating its
relative position to the mass of iron on the solenoid or sucking magnet or on the
core, or the height of the solenoid or sucking magnet with its core above this mass
may be regulated whereby a similar result will be obtained. It will be perceived
from the foregoing that the solenoid or sucking magnet with the pieces of soft iron
constitute a combined solenoid or sucking magnet and electro magnet, by the

page_text: .
different functions of which, exercised in unison, the results before mentioned and
hereinafter more fully described are accomplished
Two modifications of this construction of lamp are illustrated respectively in
Figures 1 and 2 and Figures 3, 4 and 5 of the accompanying sheet of drawings.
Figure 1 is a side elevation of one form of the electric lamp in which the upper
carbon is moveable and the lower carbon fixed and Figure 2 is a front elevation of
the same.
Figure 3 is a side elevation of an electric lamp in which both the uper and lower
carbons are moveable and Figures 4 and 5 are sectional detail views of the same
taken respectively along the lines x x and y y (figure 3)
Referring to figures 1 and 2 A represents a solenoid or sucking magnet
supported in a circular frame B of brass or other suitable metal by means of pivots
or screws CC so as to be capable of moving in a vertical plane. Through the
hollow centre of the solenoid or sucking magnet I place a rod or tube a (see details
Figure 11 and Figure 11ª hereinafter fully described) the said rod or tube being in
fact the core formed partly of soft iron and partly of brass or other non magnetic
material. At the centre of the said core at its outer end or that end nearest the
carbon I place a projection c provided with one or more points or with a knife edge
or edges either flat or curved or of other suitable form for supporting the upper
carbon E. In the drawing I have shown the projection e provided with a curved
knife edge c' which partially embraces and supports the said upper carbon. I also
provide a disc or other shaped mass b of soft iron at this end of the solenoid or
sucking magnet either on the body of the solenoid or sucking magnet (Figure 11)
or on its core (Figure 11a) and beneath the mass b of soft iron I place a second
mass b (Figure 1) of soft iron which may be adjusted nearer to or further from
the mass b by means of a screw d fitted in a socket in the mass 6¹ and capable of
turning therein and screwing through the lower plate or bar e as is well understood
or by any other convenient means; the parts Abb¹ forming in fact together a
combined solenoid or sucking magnet and electro-magnet. The circular frame B is
provided at its top with another plate or bar e (as well as with the one above
mentioned at its lower portion) the said plates or bars supporting the guiding and
contact rollers ffff³. Each pair of rollers is connected together by springs
which connect their axles, one of the axles of each pair working in horizontal
slots formed in the bars or plates ee as shown. The rollers are thus caused to
bear with more or less pressure upon the carbon passing between them, thereby
adapting them for varying sizes of carbons within certain limits. The outer
rollers ff serve to react against the pressure exerted by the core of the solenoid or
sucking magnet upon the upper carbon. The plates e e may be screwed to or cast
in one piece with the frame B. Screws g g' are employed for limiting the
movement of the solenoid or sucking magnet A and thus the length of arc between
the carbons as hereinafter described. The fine wire of the solenoid or sucking
magnet is arranged in a shunt between the terminals F F which are screwed to
the frame B of the lamp as shown. One of these terminals must be insulated from
the said frame and F is so shown and is connected by means of a conductor h
with the lower carbon carrier G which supports the fixed lower carbon H. The
said lower carbon carrier G is insulated from the other portions of the lamp as
shown at I.
The construction of the solenoid or sucking magnet which I prefer to employ is
shown in Figures 11 and 11ª which two modifications only differ from each other
in the arrangement of the piece of soft iron b as previously described. i represents
a brass or other non-magnetic tube upon which the wire a' forming the solenoid
or sucking magnet is wound provided on its exterior with an iron or other metal
envelope k having on its outer surface two recesses in which the points of the
pivots or screws C C enter for the purpose of supporting the said solenoid or
sucking magnet. Through the tube i passes a core a preferably tubular, one part
of which is formed of soft iron, while its other part m is formed of brass or other
non-magnetic material. At the front end of the solenoid or sucking magnet

page_text: namely at that end which is nearest the carbons I fix the mass b of soft iron in
any convenient manner as shown in Figure 11 or (as I prefer) the said mass may
be attached to the core as shown in Figure 11ª or it may be formed in one piece
with the soft iron portion thereof. At the central portion of this end of the core
is the projection or knife edge c previously referred to for supporting the upper
carbon as above stated. I prefer to insulate this projection or knife edge as shown
for the purpose of preventing sparking at this point. At the other or back end of
the solenoid or sucking magnet is secured a frame n carrying a pin or spindle n¹
partially screw threaded and carrying a nut n² for adjusting the pressure with
which the spring o encircling the said pin or spindle n¹ forces the core a composed
of the parts m outward against the upper carbon. The solenoid or sucking
magnet A is provided with an adjustable spring p arranged for keeping the same
in a horizontal or nearly horizontal position. The suspending rod K at its top is
bent at right angles and provided with an adjustable suspending ring K¹ as shown
so that the lamp may be hung in a vertical position.
The lamp operates in the following manner viz. The carbons being apart in
the first instance and the current switched on, it passes through the shunt solenoid
or sucking magnet drawing inward the core & and projection or knife edge c
against the pressure of the spring o and allowing the upper carbon to fall and
come in contact with the lower carbon. At the same time the mass b is magnetised
and tends to attract the mass b¹ but since the latter is fixed the solenoid or sucking
magnet is attracted towards it and so turns or swings on its pivotted axis through
a small are against the action of the spring p. The carbons being now in contact
the current is nearly wholly diverted from the solenoid or sucking magnet and
passes through the carbons whereupon the core being no longer sucked in wards
the spring o immediately forces it out into contact with the upper carbon while the
spring p pulls the solenoid into a horizontal or nearly horizontal position and into
contact with the stop-screw g at the same time lifting the upper carbon, which is
now held by the end of the core, a short distance and striking the are the length of
which is determined by the suitable adjustment of the mass b¹ and screws g g'.
As the carbons gradually burn away the resistance of the arc increases when more
of the current necessarily passes through the solenoid or sucking magnet drawing
in the core and allowing the upper carbon to descend a little. This continued and
rapidly recurring action of the solenoid or sucking magnet causes the lamp to burn
steadily whilst in use.
In lieu of the lower electrode remaining fixed as in the arrangement above
described and the regulation being produced only by the lowering or raising of the
upper electrode the regulation may be assisted by the movement of the lower
electrode which may be attached by an elbow shaped hinged lever or other suitable
means to the moveable solenoid or sucking magnet and so raised or lowered in
accordance with the movements of the latter.
This form of lamp is shewn in figures 3, 4 and 5 in which the lower carbon is
held in a spring holder q resting in the lower carbon carrier G. Two pins q' project.
from the spring holder g through slots in the sides of the lower carbon carrier and
these pins are each embraced by the slotted ends of two rods or levers as one of
which is pivoted on each side of the lower carbon carrier at t. The other ends of
these rods 8 8 are pivoted to but insulated from a forked rod u which passes up
by the side of the lower carbon carrier and through a hole at u¹ in the lower plate
or bar e and is provided at its upper end with a small roller which is in contact
or nearly so with the solenoid or sucking magnet. With this arrangement it will
be readily seen that when the front portion of the solenoid or sucking magnet
swings downward it will depress the forked rod u and with it the back ends of
the rods or levers s s raising their front ends, which embrace the pins q¹, and the
lower carbon until the carbons come in contact when the current being nearly wholly
diverted from the solenoid or sucking magnet the spring p is allowed to raise the
solenoid or sucking magnet and lift the upper carbon while the lower carbon falls
by its own weight thus jointly striking the arc. I may in some cases pivot the

page_text: top of the rod u to the bottom of the solenoid or sucking magnet so that when the
latter rises it depresses the lower carbon in consequence.
In another modification the solenoid or sucking magnet may be fixed and the
piece or mass of soft iron b¹ may be moveable and assist in the regulation of the arc
by being attached by suitable means to the lower electrode
This modification is shown in Figures 6, 7 and 8. Figure 6 being a side
elevation Figure 7 a horizontal section taken along the line y' y¹ (Figure 6) and
Figure 8 a vertical section taken along the line xx¹ (Figure 6). The solenoid or
sucking magnet is held in a fixed position by means of the screws C C being
screwed up tight and a projection C on the inside of the frame B fitting on the
top of the said solenoid or sucking magnet or this projection may be dispensed
with and the two screws G G¹ shewn in dotted lines may be screwed down upon
the top of the said solenoid or sucking magnet as shewn thus preventing it from
moving or the solenoid or sucking magnet may be otherwise rigidly attached to
its frame.
The mass b of soft iron is formed in one piece with or rigidly attached to a
plate rod or bar 62 pivoted at 63 its arc of movement being limited by the screws b*
as shown. To the mass 6' of soft iron is rigidly fixed the upper forked end u³ of
the rod u and its lower forked end is pivotted to but insulated from two rods or
levers 88 as shewn. These two rods which are pivoted at t¹ embrace at their
forward ends pins q q² projecting from the lower carbon holder q³.
The lamp operates in the following manner viz. The carbons being apart as
before and the current switched on, it passes through the shunt solenoid or sucking
magnet withdrawing the core from the upper carbon and allowing the latter to
descend. At the same time the mass b of soft iron becoming magnetised attracts
the mass blifting the same and with it the forked rod u together with the lower
carbon and the attached parts until the carbons come in contact when as before
the current being nearly wholly diverted from the solenoid or sucking magnet the
mass b¹ is allowed to fall away from the mass b thereby lowering the lower carbon
and striking the arc. The further action is similar to that occurring in the other
forms of lamp previously described.
The arrangement of the other parts of the lamp not described in this modification
is the same as that of the corresponding parts hereinbefore described with reference
to Figures 1 and 2.
In a further modification the whole arrangement of parts may be reversed as will
be readily understood. For example the solenoid or sucking magnet arrangement
instead of regulating the descent of the upper electrode which tends to fall by
gravitation may be employed to regulate the ascent of the lower electrode which
may have a tendency to rise imparted to it by means of a spring or counterweight
or other suitable device.
This modification is shown in side elevation in Figure 9 wherein it will be
seen that the arrangement of the solenoid and its attached parts is substantially
the same as that shown in Figures 1 and 2 except that it is the lower carbon or
electrode which is the one regulated in this case, the upper carbon being fixed.
The lower carbon H whose end is fixed in a spring holder vor other suitable device
passes freely down a tube L forming part of the lower carbon carrier.
This spring
holder has a ring or hook or other suitable projection which passes through a
vertical slot on the inner side of the said tube L. A tendency to rise is imparted
to the lower carbon by connecting the projecting portion of its spring holder v
with one end of a flexible string, cord, chain, or wire, v', passing over a pair of
pulley blocks M M its other end being made fast to one of the said blocks.
string, cord, chain or wire v³ attached to the lower pulley block carries a weight vs
which descends in a tube when the pressure of the solenoid core is taken off the
lower carbon which is thus caused to rise. The action of this lamp will be readily
understood from the action of the other lamps described above it being observed
however that in this modification the front end of the solenoid or sucking magnet
that is to say the end facing the carbon swings upward and then downward into a
A

page_text: horizontal position when regulating the position of the lower carbon instead of first
swinging downward and then upward into the horizontal position as in the first
two forms of lamp above described in which the position of the upper carbon is
regulated. It will be seen that the mass screws y g¹ and spring p are inverted
in position for effecting the movement desired. By using a suitable number of
sheaves in the pulley blocks the movement of the lower carbon may be made large
for a small movement of the weight v³.
I may in some cases arrange the carbons horizontally the same methods of
regulation being employed by using the solenoid or sucking magnet arrangement
to regulate the length of the are the carbons being acted upon by a spring or other
equivalent device tending to bring them together. In this arrangement it will be
readily understood that one of the electrodes may remain 6xed while the other is
acted upon for regulating purposes or both electrodes may be movable and so acted
upon.
Figure 10 is a side view of a lamp in which the carbons are arranged horizontally
the arrangement of the various parts being substantially the same as that in the
last form of lamp described.
One of the carbons in this formin of lamp as well as one in that last described is
fixed but either or both of them may be made moveable by means substantially the
same as those described with reference to figures 3, 4 and 5.
Instead of employing a pair of pulley blocks and descending weight to feed the
carbon in this and the last form of lamp described when the pressure of the core
is removed from the carbon, I may employ a coiled spring enclosed in a spring
barrel similar to those employed in clocks and combine and operate the same in
any convenient manner. For example the spring barrel may be caused to wind
upon itself a flexible string, cord, wire or chain, one end of which is connected to
the spring holder or other device holding the carbon while its other end is fixed to
the spring barrel.
I may in some cases wholly or partially insulate the guide wheels from the rest
of the lamp and convey the current from the terminals F F¹ to the carbons by the
employment of any suitable form of flexible conductor.
For the purpose of preventing the projection or knife edge c, mass b, and core
turning within the solenoid or sucking magnet I form projections or guides A' A'
on the end of the same between which the mass b is placed as shown.
I may also
attach the projection or knife edge c to the core. by screwing or otherwise so as to
render it capable of adjustment relatively to the carbon.
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 an electric arc lamp, the employment in regulating the feed of the
carbon or carbons or electrodes, separating the carbons or electrodes and striking
the arc, of a pivotted or swinging solenoid or sucking magnet, arranged as a shunt
or derived circuit between the terminals of the lamp, and having its moveable core
acting directly on one of the carbons or electrodes substantially as hereinbefore
described.
Second-In an electric arc lamp, the employment of a combined solenoid or
sucking magnet and electro magnet, in regulating the feed, separating the carbons
or electrodes and striking the arc, substantially as herein before described.
Third-In an electric arc lamp, the employment of a combined solenoid or
sucking magnet and electro-magnet, the core of which carries a gripping device
acting upon one of the carbons or electrodes to regulate the feed, whilst its armature
brings the said gripping device into a position to separate the carbons or electrodes
and form the arc substantially as hereinbefore described.
Fourth In an electric arc lamp the employment of a combined solenoid or
sucking magnet and electro magnet, controlling by its core the feed of one of the

page_text: carbons or electrodes, and by a pivotted armature separating the carbons or electrodes
and striking the are substantially as herein before described.
Fiftb The general constructions, arrangements and combinations of parts con-
stituting electric are lamps, substantially as herein before described with reference
respectively to Figures 1, 2, 11 and 11, Figures 3, 4, 5, 11 and 11", Figures 6, 7, 8,
11 and 11, Figures 9, 11 and 11*, and Figures 10, 11 and 11° of the accompanying
drawings.
In witness whereof I the said James Grieve Lorrain have hereunto set my
hand and seal this twenty sixth day of January in the year of our Lord
One thousand eight hundred and eighty three.
J. G. LORRAIN
(L.S.)