Improvements in Electric Arc Lamps.
Year: 1899

page_text: Date of Application, 25th Mar., 1899-Accepted, 6th May, 1899
COMPLETE SPECIFICATION,
Improvements in Electric Arc Lamps.
I, ROBERT FREDERICK HALL, of Ferndale, Church Road, Moseley, near the City
of Birmingham, 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 manner:-
This invention has relation to electric arc lamps, and has for its object, to
provide a positive and simplified form of feed mechanism.
The feeding mechanisms in general use are chiefly dependent for their feed
upon the slip or vertical drop of the carbon, which is controlled by various means.
Such slip or drop feeds are crude in their operation and unreliable in action, and
give rise to objectionable fluctuations of the light.
According to my invention however these defects are obviated and the general
mechanism which controls or actuates the feed is both simplified and rendered
positive in its action by the employment of a slow spiral groove or slot of the
character of an Archemedian screw formed preferably within the walls of an
upright tube, having in its interior, the carbon holder which has an arm proceeding
from it through the spiral slot in the said tube and fitted at the outer end with a
device which embraces, but is capable of sliding without twisting, upon one of
the members of the lamp framing, whilst the slotted tube is mounted in such a
manner as to be capable of a rising and falling movement and carries upon
it one clement of a brake the other element of which is carried and controlled
by the solenoid, so that when current passes into the lamp, the solenoid comes
into operation and the brake elements are brought together, the slotted tube is
lifted and carries with it the carbon holder and carbon to a height sufficient
for striking the arc.
Figure 1 of the accompanying drawings represents partly in elevation and
partly in vertical section, an arc lamp embodying my improvements.
Figure 2 represents, upon an enlarged scale, another view of the said lamp
showing more clearly the arrangement of the parts constituting my invention.
Figure 3 is a cross section of Figure 2 upon the dotted liner, showing the
arrangement of the carbon holder within the spirally slotted tube and the guide
embracing the framing member.
Figure 4 is another cross section of Figure 2 but taken upon the dotted liner,
showing the disposition of the rollers which support the slotted tube.
Figure 5 is a detail view of the said tube separately, showing the disposition
and extent of the spiral slot.
The same letters of reference indicate corresponding parts in the several figures
of the drawings.
and are the upper and lower carbons of the lamp, the latter of which is
fixed and supported in the usual way whilst the upper end of the former carbon
is secured to a holder c, located within the upper part of a centrally disposed
vertical tube d, and having an arm c', projecting from it and passing outwardly
through a spiral gap slot or opening d', in the walls of the said tube, with a
roller, on the said arm bearing on the edges of the slot to minimise the friction.

page_text: The outer end of the said arm is made in the form of an encircling clip, which
embraces one of the fixed vertical members e, of the framing of the lamp and is
provided also with separated anti-friction rollers c, disposed in pairs on the
opposite sides of the member e, which as will be obvious, compels the carbon
holder to always assume one definite position towards such rod. It will not be
seen that if the carbon holder he moved upwards, or allowed to fall downwards,
it can only do so in a vertical line, and therefore cannot move without revolving
the tube in which it is partially enclosed, by means of the spiral groove or slot,
through which its arm projects, and embraces the stationary rod as explained.
This spirally slotted tube has at its upper end a disc or cone d³, which forms
an element of a conical friction brake. The core f, of the solenoid is arranged in
the same vertical plane and a conical attachment f', on its bottom end is made
to embrace the cone at the upper end of the slotted tube and thus constitute the
second element of the brake. On the upper end of the solenoid, the dashpot is
arranged.
The operation of the arrangement is as follows:-
On applying electric current, the core of the solenoid is drawn upwards which
brings its brake element into contact with the friction brake disc on the spirally-
slotted vertical tube, and thereby lifts this latter bodily upwards.
It will now be seen that the carbon holder that is inside this tube must be
lifted also, on account of its inability to turn round, and as the tube is suspended
and lifted by the brake and cannot revolve, both have to lift together as one part.
and it is thus the arc is struck. As the are lengthens and carbons are consumed
the core of the solenoid gradually descends and the vertical tube comes to rest on
the rollers at its bottom end, whilst a further descent of the said solenoid causes
its brake part to come slightly away from the corresponding brake portion of
the vertical tube, and reduce the frictional contact between them and immediately
this happens, the weight of the carbon holder inside the tube overcomes the
remaining friction of the brake parts sufficiently to cause the vertical tube to
slightly revolve upon its supporting rollers 9, and in doing so it allows the carbon
holder to descend, so that the carbons come closer to each other. This immediately
causes a rush of current and the solenoid lifts its core up again to strike the arc,
bringing the brake parts into action and lifting bodily the whole tube, carbon,
and carbon holder and so it repeats the operation until the carbon is exhausted,
the feed throughout being smooth and uniform.
In enclosed lamps considerable difficulty and loss through breakage is caused
by the cleaning of the small globe that encloses the are. These globes are usually
fastened by means of screws and washers, and it is in the screwing and unscrewing
that the breakage occurs.
I propose, as a further part of my invention, to obviate this danger. by
permanently fixing the said globe or cover to a swinging base, so arranged that
when it is required to clean the same, the cover is swung over, so that it hangs
suspended upside down. The carbon can now be easily removed, and all dust will
fall out and the globe can be readily wiped and then reversed to its normal
position in which it is secured by a small clip spring.
The method of mounting the said glass cover which encloses the opposed or
meeting end parts of the two carbons is shown in section in the lower part of
Figure 1.
Figure 6 represents, upon as enlarged scale, an elevation of the said globe and
its mounting, with the parts in their normal positions.
Figure 7 is a like elevation as Figure 6 but showing the said globe in the act
of being turned from its normal vertical position into an angular or inverted
position to facilitate the cleansing of the same.
is the inner globe or glass cover enclosing the adjacent ends a², 2, of the
upper and lower carbons, with the open upper end h¹, normally closed by a cap
or cover, sliding upon the top carbon, whilst its lower end h³, is secured to a
swinging base i, pivoted at ¹, to the lower termination j', of the side rods j of

page_text: the lamp framing. The means for attaching the said globe may consist of a
rubber faced internal fitting k, carrying the lower carbon holder &, and having
a stalk, extending through the open bottom of the globe and through the
conical rubber faced seating, in the swinging carrier i, so that when the parts
have been assembled as shown in the sectional view Figure 1, the screwing up
of a nut, on the said stalk, causes the conical bottom of the globe to be
clamped between the inner and cuter rubber faced parts.
To maintain the said globe in an erect position as shown in Figures 1 and 6,
the swinging base is provided with a spring arm m, the free end m³, of which
is adapted to embrace one of the fixed frame rods, but is so arranged as to be
automatically disengaged therewith on the globe being pulled outwards for
swinging it into an inverted position and to snap home and fasten the said globe
on the latter being returned to an erect or vertical position.
It is of course understood that the top carbon has to be raised before the globe
can be swung over and that the top cap h³, is loosely fitted and is removed prior
to the globe being moveil.
Having now particularly described and ascertained the nature of my said
invention, and in what manner the same is to be performed, I declare that what
I claim is:.
First. In electric are lamps, the employment as a means for controlling or
regulating the feed of the carbon, of a spirally slotted vertical tube or equivalent,
which is supported so as to be capable of rising, falling and rotatory movements
and has within it, a carbon holder provided with an arm extending through the
spiral slet and embracing a guide rod or member, in combination with a friction
brake device for connecting the feed tube with the solenoid, substantially as
and for the purpose described and set forth.
Secondly. In electric arc lamps having a spirally-slotted vertical tube for
controlling the carbon feed, the employment of a series of rollers adapted to
support the said tube when released by the brake element of the solenoid,
substantially as described and set forth.
Thirdly. In electric arc lamps, mounting the globe or glass cover enclosing
the adjacent ends of the upper and lower carbons upon a pivoted base or carrier,
provided with a spring catch or equivalent fastening, substantially as and for the
purpose described and set forth.
ROBERT FREDERICK HALL.
By Henry Skerrett,
24, Temple Row, Birmingham,
Agent for Applicant.