ARO LAMPS
Year: 1881

page_text: PROVISIONAL SPECIFICATION left by the said James Brockie at the
Office of the Commissioners of Patents on the 15th October 1881.
JAMES BROCKIE, of Brixton, in the County of Surrey.
ELECTRIC ARO LAMPS."
"IMPROVEMENTS IN
This Invention has reference to certain improvements in the construction of
electric lamps which regulate on the periodical principle, where the carbons are
momentarily allowed to touch each other at certain intervals and then be separated
again the requisite distance by the action of a magnet and clutching device, for
which Letters Patent were granted to me 19th September 1879, No. 8071.
According to that Invention I proposed to regulate the lamps at frequent intervals
arbitrarily, and not dependent on the strength of the current. For this purpose I
constructed the lamps with the positive carbon holders worked by a clutching
device in such a manner that when the clutch was not affected by the magnet of
the lamp, the carbon holder was free to fall until the top carbon came in contact
with the lower or bottom carbon, which was preferably stationary; but when the
maguet was active the clutch was lifted up, carrying the holder with it, thus
separating the carbons a well defined distance, in fact, the correct distance for a
good arc. Now I placed the said lamp magnets, not in the main circuit, as in most
lamps, but in a shunt circuit parallel to the main wire and not bridging the arc.
I placed a commutator or interrupter in this said shunt circuit, which was revolved
by the engine or machine producing the current, and this interrupter momentarily
broke the said magnet circuit, thus permitting the clutch and holder to descend
until contact was made between the carbons, and then rapidly lifting them again
the correct distance; thus the carbons in the lamps were re-adjusted instantaneously
at frequent intervals, say, every thirty seconds, and not by the strength of the
current. I also proposed to construct lamps on the above principle having two
pairs of carbons with a locking device to permit only one pair to come into contact
at a time.

page_text: The first part of this Invention has reference to lamps having two or more pairs
of carbons, so that when one pair is consumed the other pair are brought into
action, and so the lamp continues to burn. The improvement consists in working
all the clutches by the one magnet in the lamp simultaneously, so that all the pairs
of carbons with which the lamp may be furnished are brought into momentary
contact at the regulating periods. It will be seen that at these periods the current
will have several paths open to it, as the carbons will be all in contact, but as the
several pairs of carbons are not of identical resistances the arc will be established
between the pair having the least resistance, or between the pair last in contact,
as for various mechanical reasons it is impossible to separate two or more inde-
pendent pairs of carbons with absolute synchronism. Now I find that the current
having once established itself between a certain pair of carbons, and although the
other pair or pairs are subsequently brought into momentary contact, the current
will still prefer the circuit of the carbons already alight, and therefore the original
pair continues to burn until they are consumed, or rather when the carbon holder
by means of a stop can fall no further; when this takes place, and the said carbons
can therefore no longer actually touch each other, the arc will be established
between another pair of carbons at the next commutating or regulating interval;
this pair will then continue to burn in the same manner as the first until the holder
comes to a similar stop, when, if the lamp be provided with a third pair of carbons,
the are will then be established between them, and thus the lamp continue to burn.
Indeed it will be readily seen that several pairs of carbons could be supplied to a
lamp, and operated by one magnet in accordance with this principle, and thus a
continuous light for many hours be maintained.
The second part refers to the regulating principle of such lamps, the object being
to dispense with the shunt or magnet conducting wires, which are necessary when
an arbitrary regulator of the lamps is driven by the dynamo machine, as explained
in the Specification of the said Letters Patent.
By that method the lamp magnets which are placed in parallel shunts are either
cut out or short circuited momentarily independently of the strength of current;
now, on the contrary, I propose to place the lamp magnets in the main circuit,
that is, the magnet directly operating the clutches, and short circuiting this said
magnet by means of the action of a shunt coil either differentially wound by the
main current conductor and shunt across the arc, or by a simple shunt coil across the
arc. The action of this will be as follows:-When the current is established in the
circuit the main magnets in the various lamps will become active and separate the
carbons; now when the arc of any particular lamp becomes too long, and therefore
of a higher resistance, the shunt coil bridging the arc will overcome its tension
spring and attract its armature against contact pieces, which pieces form a short
eircuit on the main magnet; the magnet will therefore be rendered powerless and
the carbons will be allowed to fall; this has the immediate effect of weakening the
shunt coil and breaking the short circuit, so that the main magnet will at once pull
up the carbon holder, and the are be re-adjusted.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said James Brockie in the Great Seal Patent Office on the 15th April
1882.
JAMES BROCKIE, of Brixton, in the County of Surrey.
ELECTRIC ARC LAMPS."
"IMPROVEMENTS IN
This Invention has reference to certain improvements in the construction of
electric lamps which regulate on the periodical principle where the carbons are
momentarily allowed to touch each other at certain intervals and then be separated
again the requisite distance by the action of a magnet and clutching device, for
which Letters Patent were granted to me in Great Britain, 19th September 1879,
No 3071.
I propose to regulate the lamps at frequent intervals arbitrarily, and not
dependent on the strength of the current. For this purpose I construct the lamps
with the positive carbon holders worked by a clutching device in such a manner
that when the clutch is not affected by the magnet of the lamp, the carbon holder
is free to fall until the top carbon comes in contact with the lower or bottom carbon,
which is preferably stationary; but when the magnet is active the clutch is lifted
up, carrying the holder with it, thus separating the carbons a well defined distance,
in fact, the correct distance for a good aro. I place the said lamp magnets not in the
main circuit, as in most lamps, but in a shunt circuit parallel to the main wire and
not bridging the arc. I place in this said shunt circuit a commutator or
interrupter which is revolved by the engine or by the machine producing the
current, and this interrupter momentarily breaks the said magnet circuit, thus
permitting the clutch and holder to descend until contact is made between the
carbons, and then rapidly lifting them again the correct distance; thus the carbons
in the lamps are re-adjusted instantaneously at frequent intervala, say, every
thirty seconds, and not by the variable resistance of the aro. I also propose to
construct lamps on the above principle, having two pairs of carbons with a locking
device to permit only one pair to come into contact at a time.
The first part of this Invention has reference to lamps having two or more pairs
of carbons, so that when one pair is consumed the other pair is brought into action
and so the lamp continues to burn. The improvement consists in dismissing the
mechanical locking device and working all the clutches by the one magnet in the
lamp simultaneously, so that all the pairs of carbons with which the lamp may be
furnished are brought into momentary contact at the regulating periods. It will
be seen that at these periods the current will have several paths open to it, as the
carbons will be all in contact, but as the several pairs of carbons are not of identical
resistances, the are will be established between the pair having the least resistance
or between the pair last in contact, as for various mechanical reasons it is
impossible to separate two or more independent pairs of carbons with absolute
synchronism. Now I find that the current having once established itself between
a certain pair of carbons, and although the other pair or pairs are subsequently
brought into momentary contact, the current will still prefer the circuit of the
carbons already alight, and therefore the original pair continues to burn until they
are consumed, or rather until the carbon holder by means of a stop can fall no
farther; when this takes place and the said carbons can therefore no longer
actually touch each other, the are will be established between another pair of
carbons at the next commutating or regulating interval; this pair will then continue
to burn in the same manner as the first until its holder comes to a similar stop,
when, if the lamp be provided with a third pair of carbons, the are will then be
established between them, and thus the lamp continue to burn. Indeed it will be

page_text: readily seen that several pairs of carbons could be supplied to a lamp and operated
by one magnet in accordance with this principle, and thus a continuous light for
many hours be maintained.
The second part refers to the regulating principle of such lamps, the object being
to dispense with the shunt or magnet conducting wires, which are necessary when
an arbitrary regulator of the lamps is driven by the dynamo machine, as oxplained
in the Specification of the said Letters Patent before referred to.
By that method the lamp magnets which were placed in parallel shunts were
either cut out or short circuited momentarily independently of the requirements of
the lamp. Now, on the contrary, I propose to place the lamp magnets in the main
circuit, that is, the magnet directly operating the clutches, and to short circuit or
reverse this said magnet by means of the action of a shunt coil, either differentially
wound by the main current conductor and shunt across the arc, or by a simple
shunt coil across the arc. The action of this will be as follows:-When the current
is established in the circuit, the main magnets in the various lamps will become
active and separate the carbons; now when the arc of any particular lamp becomes
too long and therefore of a higher resistance, the shunt coil bridging the arc will
overcome its tension spring and attract its armature against contact pieces, which
pieces form a short circuit on the main magnet; the magnet will therefore be
rendered powerless and the carbons will be allowed to fall; this however has the
immediate effect of weakening the shunt coil and breaking the short circuit, so
that the main magnet will at once pull up the carbon holder and the arc be
re-adjusted.
And in order that the Invention may be more fully understood, reference is
given to the accompanying Sheet of Drawings.
Figures 1 and 2 show two constructions of lamp embodying this principle;
Figure 1ª is a plan view of a commutator used in connection therewith. Referring
to Figure 1, the two top carbon holders A', A³, fall freely by their own weight;
two clutches B1, B2, operate the holders, lifting them up when lifted by the cam
levers c¹ and o, and allowing them to slip down when the said clutches are resting
on the bottom of the lamp. The electro-magnet M is placed between the two
holders A, A, and influences the armature C which moves on the centre pillar D;
this armature is common to both the clutches, and as will be seen, lifts them both
up at the same time. Now when a current is passed through the circuit the shunt
magnet M becomes active, and attracts the armature C which lifts both the top
bolders A¹, A³, thus separating the carbons; but the are will only be established
between one pair, as before explained. Now when the magnet M is momentarily cut
out by an arbitrary commutator or interrupter R, as in Figure 14, or momentarily
short circuited or reversed by a regulating coil E, as in Figure 2 (which represents
the modified arrangement constructed according to the second part of this
Invention), the armature will retire from the magnet, allowing the clutches B¹, B³,
to relax their grip upon the holders A', A³, thus permitting momentary contact of
the two pairs of carbons, and then lifting them up again the correct distance
for the are; but as before explained, although both pairs are thus allowed to
come into momentary contact, the pair originally lighted will retain the arc until
the stop S¹ or S³ on the carbon holder arrests its further descent, when the are will
then establish itself between the other pair of carbons.
In explanation of Figure 2, it will be observed that the clutch magnet M is
wound at its lower part in the main circuit and by a shunt coil N at its upper;
this latter coil when put in circuit by the regulating shunt coil E reverses the
polarity of the clutch magnet, and thus renders it powerless, and so the armature
and clutches fall away; but as this has the immediate effect of reducing the
strength of the regulating coil E, the reversing circuit N is at once broken, and
the main magnet being no longer reversed lifts up the armature smartly, and
the arc is re-struck, thus whenever the arc becomes too long the main magnet is
momentarily reversed and the re-adjustment effected.
I sometimes add another magnet P, Figure 8, wound in the same circuit as the

page_text: reversing coil N, and place the magnet P below the armature, so that if the
reversing coil N should prove either too weak or too strong, this additional
magnet will be certain to pull the armature C away from the poles of the clutch
magnet M.
Having thus explained the nature of this Invention, I claim,―
First. The construction of electric lamps with two or more pairs of carbons
operated upon by an armature and clutching device, in such a manner that both or
all the pairs of carbons in the lamps come simultaneously into momentary contact
at frequent intervals, and are then separated the correct distance for the arc, but Bo
that only one pair of carbons is alight at a time, substantially as set forth.
Second. The arrangement and combination of parts forming the double or
multiple pair lamp, substantially as shown in Figures 1 and 2.
Third. The construction of electric lamps having either one or several pairs of
carbons operated upon by a magnet wound in the main circuit, which magnet is
short circuited by means of a shunt coil or magnet bridging the arc when the arc
becomes too long, substantially as described.
Fourth. The construction of electric lamps having one or several pairs of carbons
operated upon by a magnet wound partly in the main circuit, and partly by a
shunt across the arc, which latter coil when put in circuit by a regulating shunt
coil wound differentially or otherwise momentarily reverses the polarity of the
clutch magnet, and therefore allows the arc to be re-adjusted, as described and as
illustrated in Figure 2 of accompanying Drawings.
In witness whereof, I, the said James Brookie, have hereunto set my hand
and seal, this Fourteenth day of April, in the year of our Lord One thousand
eight hundred and eighty-two.
JAMES BROCKIE. (L.S.)