Improvements in Electric Arc Lamps
Year: 1898

page_text: We, HIPPOLYTE DELAVAU, of 18, Rue Neuve du Bartardeau, Chatelleraut,
Vienne France, and FRANÇOIS FÉLIX BRERAT of 25, Rue du Chateau d'eau,
also of Chatelleraut, 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 certain improvements on our Patent No. 4934 of
1897 for Improvements in Electric Arc Lamps."
In our principal patent we described and illustrated a differential arc lamp,
with supply chamber in which the movement of the carbons placed obliquely and
furnished with points and pinning holes is effected by clamping arrangements;
this lamp being characterised by the fact that the current is regulated by a
relay mounted in such a manner that the electro-magnets always tend to draw
the carbons downward before they are released by the electro-magnets of the
principal current, so that, when a new carbon descends, this latter is firmly
pinned to the old carbon by the shunt electro-magnet.
The difficulties which we have met with in practice, in obtaining well pinned
carbons, has induced us to modify the construction of our lamp so as to allow of
ordinary carbons being used, that is to say, not pinned, whilst preserving all
the other advantages inherent in our system, especially in un-interrupted light,
even when the carbons are being changed.
The present application for a patent is intended to secure to us the property
in the improvements which we have effected in our lamp; and in order to make
clear in what these improvements consist we attach to the present specification
a drawing in which,-
Figure 1, is a front view of a lamp embodying our improvements.
Figure 2, is a side view of the same, and
Figure 3, is a section along the line a-b in Figure 1.
In order to understand what follows it is sufficient to refer to the particulars
of the drawing, the reference letters indicating the same parts in all the figures.
As regards purely constructional difference, our improved lamp embodies the
springs (aa) having the form of elastic plates wound as a spiral around an
axis, and the free end of which rests against the carbons stored in the supply

page_text: chambers, the form of the said chambers will be sufficiently clear from the
drawing so as not to necessitate any fuller description and especially as this is a
more matter of detail.
The essential difference between our improved lamp and our former lamp, lies
in substituting the upper primitive clamping arrangement by a system for
withdrawing the carbons from the supply chamber by means of traction rollers,
an alteration which is intended to allow, and results in allowing, the use of non-
pinned carbons, whilst preserving in the regulator its primitive functions of
drawing, pushing forward and regulating the carbons automatically during the
process, and permitting the ignition whether the two carbons be in contact or
removed from one another.
The alterations introduced into our lamp are based solely on this substitution,
and are intended to render the action practical and effective.
For the purpose of elearly explaining our invention we will describe the
improvements concurrently with the action of the lamp.
The charging of the supply-chambers is effected as before, that is to say, by
the upper part of the lamp and in the following manner. The first carbons
are arranged in such a manner that they may be in contact with and rest
against the abutment (1) attached to the lower part of the lamp. The other
carbons are then placed side by side in the supply chambers in such a manner
that the springs (a) press them continuously against the abutment (F). The
carbons being thus placed the filled supply chamber is closed.
Like the former lamp, the present one comprises a series circuit (1) and a
shunt circuit (2).
The electro-magnets (BB) actuating the lower or lighting clamps (bb) are
mounted in the circuit or series (1); the electro-magnets (1) 1) controlling the
supply rollers or traction rollers (dd) are inserted in the shunt circuit (2),
as also the regulating relay (H).
The carbons are extracted from each supply chamber by means of the rollers
(dddd) carried by a two armed support; one of these arms (1) is fixed at one
end to the side of the chamber, while the other arm (m) is movable and is
actuated by the movement of the core (E) by means of a small connecting
rod (n) secured at one end to the bottom part of the said core; the other end
being suspended according to Cardan's system from the upper part of the
arm (m). The rollers are capable of moving freely on their axis. Those on the
movable arm have ratchet teeth with which the catches (ee) come in frictional
contact. A pawl (e) prevents the recoil of each roller on the movable arm
during the regulating process.
The action of the extracting mechanism is as follows: When the coil (H)
conveys the current to the magnet (D), the core (E) is attracted upwards. This
causes the connecting rod (n) to recoil, and move the arm (m) of the support.
The catches (ee) are connected together by the link (o) which is attached to the
connecting rod (n), and are likewise moved upward and impart a rotary motion
to the toothed rollers. This movement of the rollers causes the carbons to
move along the required distance.
The attraction of the core (E) produces two simultaneous movements; one
being for causing the rollers to bind upon the carbon, and the other for causing
them to move the carbon along. The advancing movement of the carbons is
regulated by modifying the course of the core (E). by means of the nuts at
the upper part of the connecting rod. The small rod (g) at the bottom of the
movable arm serves as a butt and regulates the opening of the support.
The toothed rollers of the movable arm can move forward or backward
iu two slots SO as to be able to yield in either direction under
the rugosities of the carbons, the springs (f,f,f,) ensure the
pression of the rollers
on the latter; the same as the connecting-rod
of the movable arm acts likewise by compression on the carbons and imparts
the necessary degree of adherence for carrying them along.
com-
The lighting of the lamp is effected as follows:-In the state of rest the
clamps (66) are open; the carbons fall freely on to the tappet; when the

page_text: current is introduced into the lamp it starts from the terminal + passes to
the chamber + descends through the carbon + re-ascends through the carbon
passes to the chamber
and runs through the series magnets (BB) to issue
-
at the terminal
1
-
The formation of the arc is easily understood, at the moment when the current
is introduced into the series magnets (BB) the movable cores (CC) which are
in the interior are attracted upwards and effect the lighting; the length of the
arc at the moment when the magnets (BB) are attracted is regulated by the
course of the cores (CC) by means of nuts placed in the upper part of the
compressing rods (cc).
The regulation of the arc is effected in the following manner:-As long as
the principal current preserves its determined intensity the armature (h) of
the shunt coil (H) does not move; when this intensity is diminished the current
has a predominant action in the shunt coil (H) attracts the armature (h), which,
at each attraction opens, cuts, and closes the circuit of the shunt coil (H), and the
coils (DD); the successive attractions of the cores (EE) cause the forward
movement of the carbons described above. When however the arc is normal
the shunt coil ceases to act and the screw (h¹) comes again into contact with the
spring (h).
The automatic succession of the carbons is effected in the following manner: -
As long as the height of the carbons which are in engagement with the rollers
does not expose the bottom of the chambers the carbons contained in these latter
cannot come out but in proportion to the wear of the carbons which are in front;
those which are behind follow, and, as soon as the lower part of the chamber
is exposed the springs (a) press forward a fresh carbon which comes into engage-
ment with the rollers.
The change of carbons is effected without any interruption of the light. The
supply chambers can be charged while the action continues so that there is no
necessity for cutting off the current and consequently for extinguishing the
light.
The abutment (1) in the lower part of the lamp retains the carbons when the
lamp is not working.
The regulator has the advantage of enabling the lighting to be effected even
when the carbons are apart from one another this being due to the arrangement
of the coil (H). Now supposing the carbons to be apart from one another when
the current is introduced into the lamp; the series circuit will be broken and
the magnets (BB) cannot act; the consequence being that the voltage at the
lamp terminal is very high; the current immediately passes into the shunt
coil (H); attracts the armature (h); brings about a series of successive attractions
At the
of the cores (EE) which produces a rapid advance of the carbons.
moment when these latter come into contact the series circuit is closed the
magnets (BB) act immediately, detach the carbons, effect the lighting, and
the shunt coil (H) ceases to act in consequence of the sudden diminution of the
voltage at the lamp terminal; the shunt coil further is regulated so as to act
when the arc exceeds for instance 45 volts. In lighting the lamp the carbons
being in contact, the shunt coil does not move, because, the greater part of the
time, the limit of 45 volts is not reached at once; in case this limit be reached
the shunt coil rectifies it immediately.
Our lamp is a constant potential lamp; that represented in the drawing works
with a continuous current; very slight alterations, and such as any person skilled
in the art will easily understand, would render it capable of working with any kind
of current; with alternating current it displays even a certain degree of superiority.
Having now particularly described and ascertained the nature of our said in-
vention and in what manner the same is to be performed, we declare that what
we claim is :-
In an electric arc lamp, having supply chambers for the carbons and a regulator,

page_text: the rollers (d) and parts connected therewith for withdrawing the carbons from
the supply chambers, substantially as herein set forth.
Dated the 24th day of October 1898.
W. D. ROWLINGSON,
7, Quality Court Chancery Lane, London, W.C.,
Agent for the Applicants.