An Improvement in Electric Arc Lamps.
Year: 1894

page_text: An Improvement in Electric Arc Lamps.
I, JAMES BROCKIE, of 12 Tyson Road, Forest Hill, in the County of Kent,
Engineer, do hereby declare the nature of this invention to be as follows:-
:-
My invention relates to electric are lamps of the kind in which the regulation of
the arc and feed is effected by a clutch.
In such a lamp, when the clutch is released, the carbon holder rod, being for
the moment quite unchecked, tends to move beyond the required distance, often
bringing the carbons into contact and consequently producing great irregularity
of action.
My invention has for its object to provide against this defect. For this purpose,
I make the carbon holder rod taper to a somewhat larger diameter at the upper
than at the lower end.
When the clutch slightly opens to release it, the descent can only be very small
as an enlarged diameter almost immediately presents itself to the clutch which
thereupon holds it until it again releases it.
In a lamp in which the clutch is applied directly to the carbon, I make the
carbon tapered or of such shape as to act with the clutch as if it were tapered, as
for instance by making the carbon with a projecting rib or a pair of such ribs which
project somewhat farther at the upper than at the lower end of the carbon.
Dated this 26th day of September 1894.
ABEL & IMKAY,
Agents for the Applicant.
I, JAMES BROCKIE, of 12 Tyson Road, Forest Hill, in the County of Kent,
Engineer, 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 :---
My invention relates to electric arc lamps of the kind in which the regulation of
the arc and feed is effected by a clutch.
In such a lamp, when the clutch is released, the carbon holder rod, being for
the moment quite unchecked, tends to move beyond the required distance, often
bringing the carbons into contact and consequently producing great irregularity of
action.
My invention has for its object to provide against this defect. For this purpose,
I make the carbon holder rod taper to a somewhat larger diameter at the upper
than at the lower end.
When the clutch slightly opens to release it, the descent can only be very small
as an enlarged diameter almost immediately presents itself to the clutch which
thereupon holds it until it again releases it.

page_text: In a lamp in which the clutch is applied directly to the carbon, I make the
carbon tapered or of such shape as to act with the clutch as if it were tapered, as
for instance by making the carbon with a projecting rib or a pair of such ribs which
project somewhat farther at the upper than at the lower end of the carbon.
Figs. 1 and 2 of the accompanying drawings are side views shewing in two
positions a known form of clutch operating on a rod modified according to my
invention, and Fig. 3 is a plan on X X of Fig. 2.
Fig. 4 is a side view and Fig. 5 is a plan shewing a similar clutch operating in a
groove of the rod.
Referring first to Figs. 1, 2 and 3, the carbon holder is a vertically sliding rod A
which is often made round, but which in carrying out my invention I preferably
make of rectangular section as shewn.
Usually this rod is of uniform diameter or width throughout its length. The
clutch is in the form of a slotted lever B having across its slot pins C which, when
the lever is more or less inclined, grip the rod between them. The lever B is
connected by a link D to the core of a solenoid S the coil of which is in the lamp
circuit. When the lamp is not in action the solenoid core is down and the lever B
rests on the lower stop P the carbons being then in contact.
When the lamp is
put in circuit, the solenoid is excited attracting its core upwards. By the first
part of the upward movement of the core the lever B is canted into such a position
that its pins C clutch the rod A, and then as the core ascends further the rod A
is lifted as far as permitted by the upper stop P¹ raising the upper carbon and
cansing the arc to be struck. Afterwards, as, owing to consumption of the carbons,
the resistance of the arc increases, the attractive power of the solenoid is lessened,
and its core descends. If the lever B is thus so far inclined as to release the grip
of its pins C, the rod A, as it is usually constructed of equal width throughout its
length unless it is controlled by some retarding mechanisin, may suddenly descend,
bringing the carbons into contact and extinguishing the are for a moment until the
solenoid core ascends and again causes the arc to be struck. This sudden extinction
and renewal of the are has been found so objectionable that many elaborate
controlling mechanisms have been devised to provide against it.
According to my invention, I provide effectually against any considerable
movement of the rod A, when it is released, by tapering it, making its upper part
a little wider than its lower part. Thus when on release of the rod A by the
clutch a slight downward movement takes place, this movement brings a wider
part of the rod into engagement with the clutch, which, having had its pressure
on the rod only very slightly relieved, grasps the rod again at its somewhat wider
part.
When the rod A has to be of considerable length, the taper may be made in
several steps, as shewn in Fig. 2 by the dotted line indicating an upper step, the
clutch in this case being shewn grasping the upper part of the lower step. When
the clutch passes the top of the step there is a sudden descent of the rod A causing
momentary extinction and renewal of the arc, but as this can only occur once in
several hours, it involves no serious objection.
The clutch shewn in Figs. 4 and 5 differs from that shewn in Figs. 1, 2 and 3
only in that the clutch pins C act on the sides of a groove formed in the rod A,
and consequently the upper part of the groove is made according to my invention
narrower than the lower part. In like manner if the clutch were arranged to act
within a tube, the tube according to my invention would be made tapering to less
diameter upwards.
Instead of pius C operating as the clutch, rollers may be used, or the clutch
may have the known form of a plate or washer with a hole larger than the rod
which passes through it, the clutching being effected by the canting of the plate
or washer. The clutch lever B, instead of being directly connected to the solenoid
core, is preferably connected to it through a spring as set forth in my Specification
No. 8087 of 1893 so as to prevent shocks and undue strains resulting from sudden
excitement of the solenoid when the lamp is put in circuit.

page_text: Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed I would have it
understood that I make no claim to clutches such as are herein described, but
what I claim in respect of an electric arc lamp provided with a feeding rod and
clutch, is :-
Forming the edge or side of the rod on which the clutch operates with an
inclination to the path of its movement so that, when it begins to move on being
released, the fresh part of it thus brought to the clutch, becomes clutched in virtue
of its greater or less width without any farther movement of the clutch itself,
substantially as described.
Dond thin 17th day of Tul 1805
ABEL & IMRAY,
Agents for Applicant.

page_text: PROVISIONAL SPECIFICATION.
An Improvement in Electric Arc Lamps.
I, JAMES BROCKIE, of 12 Tyson Road, Forest Hill, in the County of Kent,
Engineer, do hereby declare the nature of this invention to be as follows:-
My invention relates to electric arc lamps of the kind in which the regulation of
the arc and feed is effected by a clutch applied to the periphery of a wheel which
is caused to revolve by the movement of the carbon holder. In such a lamp, when
the clutch is released, the wheel, being for the moment quite unchecked, tends to
move beyond the required extent, often bringing the carbons into contact and
consequently producing great irregularity of action.
My invention has for its object to provide against this defect. For this purpose
I make the periphery of the wheel, not circular, but of volute or spiral form, so
that as the wheel is made to revolve when the clutch is released, it brings a part of
somewhat larger radius into contact with the clutch, its motion being thus checked
until the clutch again releases it.
D1'. 103
ד
CTI 1005
ABEL & IMRAY,
Agents for the Applicant.
I, JAMES BROCKIE, of 12 Tyson Road, Forest Hill, in the County of Kent,
Engineer, 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 :-
My invention relates to electric are lamps of the kind in which the regulation of
the arc and feed is effected by a clutch applied to the periphery of a wheel which
is caused to revolve by the movement of the carbon holder. In such a lamp, when
the clutch is released, the wheel, being for the moment quite unchecked, tends to
move beyond the required extent, often bringing the carbons into contact and
consequently producing great irregularity of action.
My invention has for its object to provide against this defect. For this purpose,
1 make the periphery of the wheel, not circular, but of volute or spiral form, so
that as the wheel is made to revolve when the clutch is released, it brings a part of
somewhat larger radius into contact with the clutch, its motion being thus checked
until the clutch again releases it.
Fig. 1 is a side view and Fig. 2 a plan shewing a clutch operating on the
periphery of a wheel which is made to revolve as the carbon moves, the wheel
being of spiral form according to my invention.
Fig. 3 is a side view and Fig. 4 is a plan shewing the clutch operating in a
groove of spiral curvature formed in the wheel.
Fig. 5 is a side view and Fig. 6 a plan shewing a clutch operating on and lifting
a wheel.

page_text: The clutch shewn in Figs. 1 and 2 is a tooth or pawl C projecting from a lever B
which is connected by a rod D to the core of a solenoid having its coil in the
circuit of the lamp. The lever B is pivotted on a radius E and the movement of
the lever is limited by two stops P and P₁ between which its tail can move.
On the same axis with the radius E is mounted a wheel A. having on it a pinion G
gearing with a rack on the carbon rod F, so that as the carbon descends the wheel is
caused to revolve in the direction of the arrow. When the lamp is put in circuit, the
solenoid attracts its core raising the rod D and causing the tooth C of the lever B first
to clutch the periphery of A and then to turn A. round in opposition to the arrow
thus raising the carbon and striking the arc. As the carbons become consumed
the attraction of the solenoid becomes less, consequently the rod D descends
releasing the clutch, and thereupon, if the periphery of the wheel were circular,
the wheel would revolve too far allowing the carbons to meet extinguishing the are
which would be again started. In order to prevent this I make the periphery
of A spiral so that when it turns a little in the direction of the arrow it brings
a part of greater radius to the clutch which prevents it from turning farther until
it again releases it.
The spiral curvature may be made as shewn in two steps or it might be in a
greater number of steps. Although the clutch in passing over the step will cause
momentary extinction of the lamp, yet as this occurs only at considerable intervals
of time it causes no serious objections.
As shewn in Figs. 3 and 4 the clutch consists of two pins C on the lever B
projecting into a groove in the face of the wheel A. The outer periphery of this
groove is not circular but of spiral form so that the clutch operates in this case
on a curve of radius diminishing as the wheel revolves in the direction of the
arrow.
As shewn in Figs. 5 and 6 the lever B has a tooth C bearing against the spiral
wheel A which it lifts in the first instance to strike the arc. Afterwards, as the
carbons are consumed, the wheel which is mounted on a frame H free to slide
between stops P P1, on being released turns in the direction of the arrow so as to
feed the carbon, but, as it turns, it brings a part of greater radius to the tooth C,
it being thus prevented from turning more than a small extent until it is released
again.
Although I have shewn a simple rod D for connecting the clutch lever B to the
core of the regulating solenoid, it is to be understood that by preference a spring
is interposed between the rod and the core as set forth in my Specification No. 8087
of 1893, in order to avoid shock and undue strain when the solenoid is suddenly
excited on putting the lamp in circuit.
Having now particularly described and ascertained the nature of my said inven-
tion and in what mauner the same is to be performed I declare that what I
claim in respect of an electric are lamp provided with a feed wheel and
clutch is :-
Forming the periphery of the wheel or of the groove on which the clutch
operates of special curvature so that when it begins to move on being released, the
fresh part of it thus brought to the clutch becomes clutched in virtue of its greater
or less radius without farther movement of the clutch itself, substantially as
described.
Thi 171 1
CT
ABEL & IMRAY,
Agents for the Applicant.