Improvements in Electric Arc Lamps.
Year: 1887

page_text: [Communicated from abroad by CHARLES MILTON NOBLE, of Anniston, Calhoun
County, Alabama, United States of America, Gentleman.]
Improvements in Electric Arc Lamps.
I, ALFRED JULIUS BOULT of 323 High Holborn, in the County of Middlesex,
M.I.M.E. 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 has relation to Electric arc lamps and more especially to that class of
arc lamps in which carbons of equal length are used and so arranged as to converge
from their point of support to their tips, and said invention consists in the improved
construction and combination of parts constituting such a lamp, as will be hereinafter
fully set forth.
In the accompanying drawings Figure 1 is a diagrammatical plan view of the
controlling mechanism of the improved lamp.
Figure 2 is a vertical central section of said lamp and Figure 3 is a view showing
in detail a side and end view of a portion of the switch used on said lamp.
Like letters of reference indicate corresponding parts throughout all the figures.
In lamps of the above mentioned class difficulties have arisen in maintaining a
regular feed for the carbons which in most instances have been arranged so as to slide
towards the point of convergence as they were consumed.
The disadvantages arising in such a system are overcome by so pivoting the carbon
holders that the tips of the carbons shall swing to the point of convergence. To
regulate this swinging so that said tips shall meet in the proper manner weights are
attached to the carbon holders which tend to keep said tips together and at the same
time said holders are linked to a rod controlled by an electro-magnet, in a manner
such that the portion of the current of the lamp which passes through said magnet
shall counteract the tendency of the weights sufficiently to keep the tips of the
carbons at the proper distance to produce the desired arc. An automatic switch is
also constructed which shall operate to cut the lamp out of the circuit when the

page_text: carbons have burned to such a point as to allow a prolongation of one of the carbon
holders to trip a lever controlling the contact points of said switch. To the
accomplishment of these ends a lamp is constructed as illustrated in the accompanying
drawings in which A designates the positive carbon which as is common when carbons
of equal length are used has double the area of cross section of the negative carbon B.
These carbons are retained in holders C which extend through apertures in the
bottom of the casing D and are pivoted upon pinions E in bearings secured to said
bottom. Through the upper end of each holder is formed a perforation in which is
placed an insulating bushing F. In said bushings are placed the shanks of the
weight arms G and upon the screw threaded end of said shank is turned a nut H
which has two parallel perforated lips projecting therefrom. The weight arms are
screw threaded and cylindrical weights I are provided with axial screw threaded
perforations that they may be rendered adjustable upon said arms so as to cause the
tips of the carbons to be borne together with great or less force as the strength of the
magnets the resistance of the carbons or the condition of the circuit may require.
Between said lips in each end H is hinged one end of a link J. The other ends of
these upwardly extending links are hinged by a pintle K to a rod L which is adapted
to slide vertically in the guide M; said guide being secured to the casing between the
helices N of the electro-magnet. The lower end of the rod L is rounded and adapted
to rest in the cup O secured upon the middle of the bar P which connects the
movable cores of said helices.
The line wires are connected to the lamp by the binding posts Q and R and from
the positive one Q a wire S within the casing leads to and is secured in the positive
carbon holder by the screw T. This same screw also binds to said holder one end of
the wire of the electro magnet, the other end of said wire being joined in a like
manner by a screw U to the negative carbon holder. This screw likewise binds the
end of the wire V which leads to the negative binding post R.
To the wire S at a point W is connected a wire X (shown in dotted lines) which
makes direct connection with the anvil Y of the switch. This anvil consists of two
springs secured to the bottom of the casing forming a V space between them into
which strikes the hammer when the current is to pass through the switch. The
handle A¹ of this hammer which is directly connected to the wire V is hinged to the
side of the casing in a bearing B. In the head of the hammer is formed a slot in
which is pivoted, upon the pintle C² the lower end of the stem D' which stem passes
up through the casing and is capped by a button E. From the upper side of the
casing and parallel to said stem there depends a post F¹ upon whose lower end is
pivoted a trigger G₁ which is actuated by a spring H' coiled about said post and
secured thereto by its upper end while its lower end bears against the side of said
trigger.
In setting the switch the hammer is lifted from the anvil by pulling up on the
button E¹ and when raised to the desired height it is maintained there by one end of
the trigger engaging in a notch I' in the stem D¹ in which notch said trigger is held
by the coiled spring.
When the lamp is to be automatically cut out of the circuit which occurs when the
carbons have been consumed till they assume the positions indicated by the broken lines
a-b; be the prolongation J of the negative carbon holder bears gently against
the inner end of the trigger till its engaged end is freed from the support of the
hammer, then said hammer falls to the anvil, and, the line current passes directly
through the casing by way of the wire X and the switch.
In a lamp constructed as above described it is essential that the carbons be very
rigidly secured in the holders, therefore a holder is constructed which has one side K¹
of its socket hinged to the rigid portion said hinged side being clamped against the
carbons by means of the ring L' which embraces both portions of the socket and the
set screw M which turns through said ring and bears against the hinged portion.
In the operation of the lamp on starting the current through it the switch being set
and the tips of the carbon bearing against each other the current through the helices
causes the bar P to rise which brings the cup O, to bear against the lower end of the

page_text: As the
rod, causing it to ascend and in ascending to draw the upper ends of the carbon
holders towards each other thereby allowing the tips of the carbons to separate
sufficiently to cause the current passing them to form the required arc.
carbons gradually burn away the weights force the points into close proximity their
nearness to each other being governed by the action of the electro-magnet as
described and when the carbons have been consumed to the desired extent the
prolongation of one of the carbon holders trips the switch and the lamp is cut out of
the circuit.
Any other known form of switch may be used for this lamp being connected
thereto in any of the common ways but the switch described is the one preferred.
Having now particularly described and ascertained the nature of the said invention
as communicated to me by my foreign correspondent and in what manner the same is
to be performed I declare that what I claim is :-
1. The combination of the casing carbon holders connected to the line wire and
pivoted in a vertical plane to the lower side of said casing, insulating bushings secured
in perforations through the upper ends of said holders, weight arms secured by their
shanks of said bushings, adjustable weights, upon said arms, and means substantially
as described for controlling the tendency of said weights.
2. The combination of the carbon holders connected to the line wire and pivoted
in a suitable support, weight arms whose shanks are passed through insulating
material in said holders, adjustable weights upon said arms, lamp bearing nuts turned
upon the ends of said shanks, an electro magnet whose coils are connected to said
carbon holders, and links pivoted in said lips and connected to the line wire and
pivoted in a suitable support, weights adjustably secured to said holders, a pair of
helices whose coils are connected to said carbon holders, a bar connecting the movable
cores of said helices, a cup upon the middle of said bar, a rod secured in a vertical
guide over said cup and links pivotally connected to said rod and to the upper ends of
the carbon holders.
3. The combination of the casing, a V shaped anvil connected to one end of the
line wire, a hammer pivoted by its handle to the side of the casing and connected to
the other end of the line wire, a stem pivoted to said hammer and provided with a
notch in its side and a trigger adapted to fit in said notch to hold the hammer from
the anvil.
4. The combination of the casing the anvil connected to one end of the line wire
the hammer connected to the other end of said wire, the notched stem pivoted in a slot
in the head of the hammer and passing up through the top of the casing, the
dependent post, the trigger pivoted to the lower end of said post, and the coiled
spring secured by one end to the post and bearing by the other against said trigger.
5. In an electric arc lamp provided with pivoted carbon holders one of which is
formed with a prolongation at its upper end the combination with said carbon holder
of the pivoted spring actuated trigger, the notched stem, the hammer connected to one
end of the line wire and the anvil connected to the other end of said wire.
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