Year: 1885

page_text: We, JAMES BROCKIE of Brixton in the County of Surrey and BENNETT PELL of
14 Union Court, Old Broad Street, London, both Electricians do hereby declare the
nature of this invention to be as follows:-
This invention relates to improvements in the construction of Arc Lamps of the
direct acting type in which the carbons are controlled by a magnet or solenoid in
such a manner that the distance between the carbons is directly increased. or
diminished according to the strength of the main current. The carbon holders
of such lamps are usually controlled by a differential magnet or solenoid which
operates a clutching device on the carbon holder rod and directly determines the
movements of the carbons.
According to our invention we employ two solenoids to control the carbons and
we place them in such a relation to each other that the regulation of the lamp is
perfect, notwithstanding considerable variations in the current employed. For
this purpose, we arrange the two solenoids above a rocking lever or beam pivotted
at its centre which operates the clutching device; the core of the one solenoid is
pivotted to one end of the said rocking lever, this solenoid is wound in the main
circuit and its duty is primarily to separate the carbons when the current is
established and thus obtain the arc. The core of the other solenoid (which is
wound in a shunt circuit across the arc) controls the other end of the rocking
lever but it is not permanently pivotted to it like the main solenoid core, this we
arrange by slotting the lower end of the shunt coil core, into which slot the lifting
pin on the rocking lever takes; thus the lever may move up and down to the
extent of the slot by the action of the main core without any corresponding
movement of the shunt coil core, but at the same time, if the shunt solenoid core
be attracted upwards, that end of the lever will be pulled upwards and the other
end of course depressed against the pull of the main coil. It will be seen that
although the action are coil is opposed to that of the other through the medium of
the rocking lever, the core of the main coil may and does operate the said lever
independently of the other core, should that core remain inactive in its lowest
position. We suspend the shunt coil core by a link the length of which determines
its lowest position so that it is quite independent of the rocking lever. By thus
arranging the two cores in relation to the rocking beam and making them semi-
independent, the main coil may only be made powerful enough to lift the one end

page_text: of the rocking lever and separate the carbons, irrespective of the strength of the
shunt coil, which latter does not come into operation until the arc is of its normal
resistance, this coil may be of very much greater power than the main coil, and the
regulating weight or spring is applied direct to the shunt coil core itself and not
to the rocking lever; thus any proportion of main current influence may be
introduced into the regulation of the lamp as may be desired, this being impossible
in differential lamps where the main and shunt coils must necessarily be of nearly
the same power or the main stronger than the shunt.
In order to make the movements of the regalating rocking lever more readily
influenced by the downward tendencies of the shunt coil core notwithstanding the
slot, we arrange the slot and lifting pin so that the magnetism of the core causes
the pin to adhere to the bottom of the slot and so become virtually directly
pivotted to it, but when the current ceases in the shunt coil, the pin is free to
take up any position in the slot and move as before stated independently of the
shunt core.
Instead of slotting the core, the lifting pin may be made large enough
at its centre to allow the solenoid core to pass through it, in which, case an iron
button at the end of the core would be used to lift the lever and to attract the pin.
In order to control the carbons by this rocking lever we attach a link to a
convenient part of the lever, this link works the clutching device on the carbon
holder rod or on the periphery of a wheel driven by the weight of the carbon rod.
We use any suitable form of clutching devices, by preference such as are described
fully in Letters Patent granted to the said James Brockie dated 16th Sept 1882
No 4419 and 29th May 1883 N° 2661.

page_text: We, JAMES BROCKIE, of Brixton in the County of Surrey and BENNETT PELL of
14 Union Court, Old Broad Street, London, both Electricians, do hereby declare
the nature of this invention and in what manner the same is to be performed
to be particularly described and ascertained in and by the following statement :-
This invention relates to improvements in the construction of Arc Lamps of the
direct acting type, in which the carbons are controlled by a magnet or solenoid in
such a manner that the distance between the carbons is directly increased or
diminished according to the strength of the main current. The carbon holders of
such lamps are usually controlled by a differential magnet or solenoid which
operates a clutching device on the carbon holder rod and directly determines the
movements of the carbons.
Fig. 1 of the accompanying drawings shews the general construction of a lamp
according to our invention; Fig. 2 is a diagram shewing the relative positions of
the solenoid cores when no current exists in the circuit; Fig. 3 is a diagram
shewing the relative positions of the cores when the arc has been started; Figs. 4
and 5 shew modifications hereinafter referred to.
We employ two solenoids A and B to control the carbons, and we place them in
such a relation to each other that the regulation of the lamp is perfect, notwith-
standing considerable variations in the current employed. For this purpose we
arrange them above a rocking lever L which is pivotted at X and which operates
the clutching device C by means of the link K. To one end of the lever L is
jointed the core A¹ of the solenoid A. the coil of which forms part of the main lamp
circuit, and its duty is primarily to separate the carbons when the current is
established and thus to start the arc. The core B¹ of the other solenoid B, which
is wound in a shunt circuit or by-pass to the arc, has a slotted connection S to the
other end of the lever L not being rigidly jointed to it like the main core A¹; thus
the lever L may be moved up and down by the main core A¹ to the extent of the
slot, without any corresponding movement of the shunt coil core B₁ as will be
understood on reference to Figs. 2 and 3. But when the pin P is at the lower end
of the slot S, the shunt core B¹ on being attracted upwards will raise one end of
the lever depressing the other in opposition to the pull of the core of the main
coil A and thus permitting the carbons to approach each other. Thus it will be
seen that although the action of the arc or main coil A is opposed to that of the
by pass coil B it.acts independently of B¹ while B¹ remains in its lowest position.
We suspend the shunt coil core by a link N Fig. 1, the length of which determines
its lowest position, so that it is quite independent of the lever L; this is shewn in
Figs. 2 and 3 in which the shunt coil core B¹ is seen suspended by its link N
resting upon the stop or table N¹. By thus arranging the two cores in relation to
the lever L and making them to a certain extent independent of one another, the
main coil need only be powerful enough to lift the one end of the lever and separate
the carbons irrespective of the strength of the shunt coil, which does not come
into operation until the arc is at or near its normal resistance; this shunt coil may

page_text: consequently be of very much greater power than the main coil (as indicated by
the relative sizes shewn) and the regulating weight W (or it might be a spring) is
applied directly to the shunt coil core itself, and not to the lever L; thus any
desired portion of main current influence may be introduced into the regulation of
the lamp, this being impossible in direct acting differential lamps, where the main
coil must be somewhat stronger than the shunt.
In order to make the movements of the regulating lever L more readily influenced
by the downward tendencies or movements of the shunt core B¹ notwithstanding
the slotted connection at S, we arrange the slot and the iron lifting pin P so that
the magnetism of the core causes the pin P to adhere to the bottom of the slot
and so to become virtually jointed to it for the time being, but when the current
ceases in the shunt coil, the pin is free to take up any position in the slot and move
as before stated independently of the shunt core.
The
Instead of connecting by a slot, the pin P may be made as an iron collar
embracing the solenoid core as shewn in Fig. 4; in which case an iron button B' at
the end of the core. B¹ is used to lift the lever and to attract the collar P.
sides and top of the slot S in Figs. 1, 2 and 3 are faced with non-magnetic metal,
such as brass, to prevent cohesion except at the bottom, and in like manner the
collar in Fig. 4 is bushed with non-magnetic material. Although we have described
the solenoids A and B as acting at opposite ends of the lever L it is obvious that
they may be arranged to act on one end, as shewn in Fig. 5. In this case the main
coil A is placed above the lever L its core being attracted downwards, and the
shunt coil B is' placed below, its core being attracted upwards. The cohesion of the
shunt core to the lever L when' the main coil has separated the carbons may be
obtained by the attraction of either core to the end of the other, thus for the
time being rendering their action differential as in the case when a slot is used as
before described. Instead of solenoids, electro-magnets may be arranged to act as
described.
In order to control the carbons by the lever L, we attach a link K to a con-
venient part of the lever; this link works the clutching device on the carbon
holder rod or on the periphery of the wheel R'driven by the weight of the carbon
holder rod D as shewn in Fig: 1.
We use any suitable form of clutching devices by preference such as described
fully in Letters Patent. granted to the said James Brockie dated 10'Sept 1882
No 4419 and 29 May 1883 N° 2661.
Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed we declare that what we
claim is :-
In arc electric lamps having a solenoid coil in the lamp circuit the core of which
when attracted acts on clutch mechanism so as to separate the carbons, and' having
also a solenoid coil in a by-pass circuit, arranging the cores of these coils in
relation to the clutch mechanism so that when that of the former has acted
independently in separating the carbons, the core of the by-pass coil opposes 'and'
influences its further movements; substantially as and for the purpose herein 'set'
forth.