Improvements in the Construction and Working of Electric Arc-lamps.
Year: 1898

page_text: Date of Application (In the United Kingdom), 1st Oct., 1898
Complete Specification Left, 3rd July, 1899-Accepted, 5th Aug., 1899
PROVISIONAL SPECIFICATION.
Improvements in the Construction and Working of Electric
Arc-lamps.
We, LA SOCIÉTÉ "LES FILS D'ADOLPHE MOUGIN," of Hericourt, in the Department
Haute Saone, in the French Republic, Mechanical Engineers, do hereby declare the
nature of this invention to be as follows:-
This invention relates to an improved construction of electric arc-lamp having
a permanent source of light and capable of being operated in any position by means
of either continuous or alternating currents.
An arc-lamp constructed according to our improved method is illustrated, by way
of example, in the accompanying drawings, whereof
Fig. 1 is a sectional elevation of the complete lamp.
Fig. 2 is a section of the binding screw or post for admitting current to the
lamp.
Fig. 3 is a detail view in section illustrating the arrangement for supplying current
to the upper carbon-holder.
Fig. 4 illustrates the method of connecting the upper carbon-holder with the
endless chain from which the carbon-holders receive the necessary motion. (the lower
carbon-holder being connected to the chain in a like manner).
Fig. 5 is an elevation at right angles to Fig. 1 showing the details of construction
of the lower carbon holder.
Figs. 6 and 7 are enlarged elevations showing in detail the working parts of the
lamp.
Fig. 8 is a plan.
Fig. 9 is simply a diagrammatic view illustrating the electrical connections and the
course of the current through the several parts of the lamp.
Fig. 10 is an enlarged view of the regulator employed for automatically starting
and stopping the clockwork which sets the carbons in motion.
'The essential feature of our lamp is the clockwork mechanism, which consists of
a barrel A secured to a spindle or arbor a (Fig. 6) and enclosing an ordinary volute or
main spring one end of which is attached to the inner periphery of the barrel while
its other end is integral with a tube concentric with the spindle a and secured to the
pillar-plate. The spring in the first instance imparts motion to the barrel, which is

page_text: provided with ratchet-teeth A¹, the motion thus produced being transmitted to the
first wheel B of the gear train through the medium of a pawl B¹ wherewith the
wheel B is provided; such wheel having 120 teeth and being loose upon the spindle a.
This wheel operates the first pinion mounted upon the spindle of the wheel b¹ the
former () having 8 teeth and the latter (61) having 84 teeth. The wheel 61 gears
with a second pinion provided with eight teeth and mounted on the same spindle
with another wheel 611 having 84 teeth. This last mentioned wheel is in gear with
the last pinion B₁ having 7 teeth, upon the spindle there is also mounted a wheel C
laterally projecting pegs or sprockets c.
A
Given the number of teeth or relative pitch of the several gear wheels thus far
described we obtain 1890 revolutions of the sprocket-wheel C to every revolution of
the spring-barrel arbor a. It is, however, not absolutely necessary to adhere strictly
to these relative dimensions, as they may be varied at will to meet the requirements
of individual cases.
The clockwork mechanism above described is disposed between two supporting
plates D D¹ (Fig. 7) connected by three pillars or distance pieces D₁ D₂ D, (Fig. 6),
the last of which, D., serves as a seat for a soft iron armature & secured to it in any
suitable manner.
The arbor or spindle a of the barrel A extends beyond the plates D D' and is
supported by two other rigid plates E E¹; the whole of the mechanism described
above being arranged to turn or swing thereon.
Between the two plates D¹ and E¹ there is mounted upon the spindle or arbor a a
toothed pinion E¹¹ on which works an endless pitch chain (or other suitable chain) E₁,
such chain extending through the hollow rods or pillars F, F1 and passing over guide-
pulleys e, e¹, ell, elll (Fig. 1). Or instead of a pitch-chain or other chain any suitable
flexible tie-piece may be adopted, in which case however there should be substituted
for the pinion E" a pulley roller or sheave with one or more grooves.
Between the two hollow rods or pillars F and F, through which passes the endless
chain E, the carbon-holders are arranged.
The upper carbon-holder G is connected with the endless chain E, on the left-hand
side (Fig. 1), while the lower carbon-holder G¹ is connected with the said chain on
the right-hand side.
The method of connection of the carbon-holders with the endless chain is illustrated
in Fig. 4 and comprises a block g fitted to the carbon-holder and into which is screwed
a rod g¹; the latter passing through the longitudinal opening for ƒ¹ in the pillar F
or and through one of the links of the chain E₁. The carbon-holders are provided
with anti-friction rollers H with a view to facilitating their movement along the
pillars FF; the longitudinal opening further permitting the said carbon-holders to
readily travel along the said hollow pillars F F¹. The opening f¹ extends along the
upper portion of the left-hand pillar F1 (Fig. 1), while the opening f is situated in the
lower portion of the right-hand pillar F. The upper carbon-holder G is insulated
from the rest of the mechanism of the lamp while the lower carbon-holder G¹ is not
insulated therefrom.
'
The means for insulating the upper carbon-holder consists of a socket or sleeve I
(Fig. 3) separated from the metal part I¹ by a washer of insulating material I¹¹¹.
From the socket I a screw 111 extends through the part G of the carbon-holder,
which, however, it does not touch; and the upper part of such screw enters a current-
receiving post i which is insulated from the part G by a plate of the same
insulating material whereof the plate I111 is constituted. At the binding post i there
terminates the wire 1. It will therefore be seen that the current arriving through
this wire must go directly through the central screw I to the upper carbon-holder
without being diffused through the other portions of the lamp mechanism.
In view of the method adopted for connecting the carbon-holders G G¹ with the
endless chain E, it will be readily understood that the motion of the chain in the
direction of the arrow 2 (Fig. 1) will have the effect of removing the carbon-holders
from each other, whilst whenever the said chain travels in the direction of the
arrow 3 (Fig. 1), the effect will be to cause the carbon-holders to approach each

page_text: other; and the said carbon-holders are thus moved nearer together through the
agency of the clockwork operated by the spring barrel, while the opposite movement
of the carbon-holders-away from each other-when the lamp is being lighted, is
brought about by the starting electro-magnet K the windings of which-comprised
in the arc-circuit-are traversed by a powerful current whenever the carbon points
meet. When this is the case, the electro-magnet K attracts its soft iron armature
d (Figs. 1 and 6) and the entire clockwork swings round upon its arbor a,
together with the pinion E", which accordingly performs a slight rotary movement
in the direction of the arrow 4 (Fig. 6), the effect of such rotation or oscillation
being to move the two carbons for a little distance apart, since the direction of
such rotation corresponds to a movement of the chain E, in the direction of the
arrow 2 (Fig. 1). Normally, whilst the armature d is not attracted the clockwork
rests against an adjustable arresting screw, by which means the amplitude of the
oscillation of the clockwork may be varied and consequently the initial length of the
arc adjusted.
We will hereinafter describe the arrangement of regulator which, when required,
arrests the clockwork or starts it, as the case may be; but, for the present, we will
examine the course pursued by the current as it flows through the lamp.
The current enters the lamp through the wire 5 terminating at the insulated
binding post L, as shown in Fig. 2; passing from thence through the starting
electro-magnet K (Figs. 1 and 6), through the wire 1 into the upper carbon-
holder. It then passes through the lower carbon-holder into the lamp and leaves
the same through the post L¹ which is in electrical connection with the lamp.
As soon as the current has thus passed through the lamp, and while the upper and
lower carbons are touching, the electro-magnet K is traversed by a very powerful
current, so that its armature d becomes attracted. The whole clockwork accordingly
oscillates on the spindle a and the pinion E" moves slightly in the direction of the
arrow 4 (Fig. 6), such movement severing the two carbons and causing them to recede
a little distance from each other the arc being thereby formed, the lamp comes into
operation.
The means for regulating hereinbefore referred to are as follows:--- On the spindle
is an oscillating flyer or pallet having at one end a stud 1 (Fig. 7) so arranged
that, normally while the lamp is in operation and the armature d is being attracted
by the starting electro-magnet K-it takes up its position between two consecutive
sprockets c of the wheel C, thereby checking any oscillatory notion of the clockwork
and maintaining the carbons at a uniform distance apart.
The end of the pallet is located above the core M of an electro-magnet, wound
with fine wire M¹, connected in parallel with the main circuit; the said fine wire
coil being, to this end, connected by the wire 6 (Fig. 7) to the binding post M",
insulated from the lamp, and thence to the wire 1; the wire 7, on the other hand,
connecting the said coil to the lamp.
When, as the result of the wear of the carbons, the resistance of the lamp increases;
the current passing through the electro-magnet M-in derivation or parallel—
increases in amount or amperage to such an extent that the core M becomes suffi-
ciently magnetised to attract the pallet, and withdraw the stud out of contact
with the sprocket-wheel thereby releasing the same. Hence the clockwork will start
revolving in the direction opposite to that of the arrow 4 and the carbons will be
drawn nearer together. The moment the resistance met with by the current
becomes normal again, in consequence of this proximity of the carbons-i.e., when
that degree of resistance is restored to which the lamp has been set-the current in
the parallel connection of the coil M will decrease in amount and the pallet / will
be brought back to its original position under the influence of the spring P which
controls it and which is shown in detail in Fig. 10. Thus the lamp will operate
automatically, and continue to regulate itself until the last stage of wear of the
carbon is reached. .
The arrangement for the control of the pallet simply consists of a spring P one
"

page_text: end of which rests upon the spindle and the other upon the inner edge of a case P¹
by the rotation of which the spring P may be compressed more or less.
It will be understood that what should be regulated in the lamp first of all is
precisely the power which this spring P is to display in its action upon the sleeve or
case P¹ so as to obtain a length of are corresponding to the current consumed.
From the foregoing remarks it will be clear that the operation of the herein
described lamp-mechanism is independent of the law of gravitation and that our
lamp may, in consequence, operate in any desired position; the only manipulation
necessary, after the lamp has once been fitted in its place, being the exchange of the
carbons as they are worn away.
To substitute fresh carbons, it is only necessary to move the carbon-holders apart,
by hand, by pressing each in the opposite direction to the other. As this operation
is heing performed the ratchet A¹ will spring over the catch of the barrel A without
engaging the wheel B; and owing to the movement thus imparted to the said
barrel A, its spring will be compressed again to the extent to which it has previously
been expanded or slackened, with the result that the mechanism still continues in
the same operative position as before.
Figs. 11 and 12 illustrate a modification of the regulating device whereby the
clockwork controlling the carbons is automatically stopped or started as the case
may be.
This modified form of regulator consists mainly of an armature R adapted to be
attracted by the core M of the electro-magnet M', such armature being subjected to
the action of a spring which tends to raise it. The tension of the spring ? is variable
at will by means of a set screw 71.
The wire 7 instead of being connected as in the arrangement previously described
to the body of the lamp by means of the plate which supports the clockwork mechanism,
is here connected to a rod 7" insulated from the plate 111. Against the lower end of
the rod or screw 711 rests a flat spring R¹ attached to the upper side of the armature R.
The elevation of said screw 11 in rotation to the spring R¹-which elevation is
adjustable at will-is such that, normally—i.e., while the armature R is not attracted
by the core M-the spring R¹ touches the lower end of the rod 11, while, in the event
of the armature R being attracted by the core M, the said spring R¹ no longer touches
the said lower end of the screw 7.11.
Hence a parallel circuit will be constantly maintained so long as too great a resist-
ance is not set up in the main circuit owing to the carbons being too far apart; but
the moment the resistance in the main circuit increases and the amperage of the
current passing through the "parallel" circuit-and also through the coil M¹-
becomes greater (with the result that the armature R is attracted by the core M) the
said parallel circuit breaks, or is opened, the spring R¹ and rod 1 having moved out
of contact. The armature R thereupon instantly resumes its initial position.
The armature R is provided at its terminal S with a plate S¹ pivoted at S" to the
pendant pieces.
The position of the plate S₁ in relation to the sprocket wheel is such that, normally,
while the armature R is not attracted by the core M, such plate S¹ is interposed
between two consecutive sprockets c, thereby checking the motion of the wheel C.
When, however, as previously mentioned, the armature R is attracted, owing to the
Increase in the current passing through the "parallel" or derived connection, the
plate S¹, in consequence of the movement of the armature R, turns on its pivot S¹¹,
in the direction of the arrow (Fig. 12), and thus releases the sprockets c so that the
wheel C is rendered capable of turning.
Thus the motion of the carbon-holders is here controlled in a manner similar to
that described above, with this difference that the controlling effect in the present
instance is obtained by means of a series of jerks following each other in very rapid
succession, inasmuch as the armnature opens the derived or parallel circuit every time
it is attracted.
The endless chain is preserved at the requisite state of tension by means of an

page_text: adjustable roller or tension device T disposed at the lower end of the lamp. T¹ T
are suspension rings.
Dated this 1st day of October 1808
Improvements in the Construction and Working of Electric
Arc-lamps.
WE, LA SOCIÉTÉ "LES FILS D'ADOLPHE MOUGIN," of Hericourt, in the Depart-
ment Haute Saone, in the French Republic, Mechanical Engineers, 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 an improved construction of electric arc-lamp having a
fixed focus and capable of operating in any position with either continuous or
alternating currents.
Referring to the drawings which accompanied our Provisional Specification and
which illustrate, by way of example, an arc-lamp constructed according to our
improved method.
Fig. 1 is a sectional elevation of the complete lamp.
Fig. 2 is a section of the binding screw or post for admitting current to the lamp.
Fig. 3 is a detail view in section illustrating the arrangement for supplying current
to the upper carbon-holder.
Fig. 4 illustrates the method of connecting the carbon-holders with the endless
chain whereby the carbon-holders are moved, the said method being shown in con-
nection with the upper carbon-holder.
Fig. 5 is an elevation at right-angles to Fig. 1 showing the details of construction
of the lower carbon-holder.
Figs. 6 and 7 are enlarged elevations showing in detail the working parts of the
lamp.
Fig. 8 is a plan corresponding with Fig. 6.
Fig. 9 is a diagrammatic view illustrating the electrical connections and the course
of the current through the several parts of the lamp.
Fig. 10 is an enlarged view of the regulator employed for automatically starting
and stopping the clockwork which sets the carbons in motion.
Figs. 11 and 12 illustrate a modified construction of regulator.
The essential feature of the present improvements consists in the clockwork
mechanism, which comprises a barrel A, secured to the spindle or arbor a (Fig. 6),
enclosing an ordinary spiral or volute spring whereof one end is attached to the inner
periphery of the barrel whilst its other end is integral with a tube concentric with
the spindle a and secured to the pillar-plate. The spring in the first instance imparts
motion to the barrel, which is provided with ratchet teeth A', the motion thus
produced being transmitted to the first spur-wheel B of the gear-train through the
medium of a pawl B¹ wherewith the wheel B is provided; such wheel having, for
example, 120 teeth and being loose upon the spindle a. This wheel meshes with and
operates the spur-pinion 6 mounted upon the spindle of the spur-wheel b¹ the former (b)
having 8 teeth and the latter (61) having, say, 84 teeth. The wheel b¹ meshes with
another spur-pinion 6 provided with 8 teeth and mounted upon the same spindle

page_text: with another spur-wheel ¿¹¹¹ having, say, 84 teeth. This last mentioned spur-wheel
meshes with the spur-pinion B, which has 7 teeth and upon whose spindle there is
also mounted a wheel C with laterally projecting pegs or sprockets c.
By the employment of gear proportioned as above described one revolution of the
arbor a imparts. 1890 revolutions to the sprocket wheel C, but it will be understood
that we do not restrict ourselves to these relative proportions and that they may be
varied at will to meet the requirements of individual cases.
The clockwork mechanism above described is disposed between two supporting
plates D D¹ (Fig. 7) connected by pillars or distance pieces D, D, D, (Fig. 6), the last
of which, D, serves as a seat for a soft iron armature & secured in any suitable
manner.
The arbor or spindle a of the barrel A extends beyond the plates D D¹ and is
supported by two rigid plates E E¹; the whole of the mechanism described above
being arranged to turn or swing thereon.
Between the two plates D¹ and E¹ there is mounted, upon the spindle or arbor a, a
chain wheel or pinion E¹¹, on which works an endless pitch-chain such as E₁, the latter
extending through the hollow rods or pillars F, F1 and passing over guide-
pulleys e, e¹, ell, el (Fig. 1). Or instead of a pitch-chain any other suitable flexible
connection may be adopted, in which case however there should be substituted for
the pinion or chain-wheel E" a pulley, roller or sheave provided with one or more
grooves.
Between the two hollow rods or pillars F and F¹, the carbon-holders G G¹ are
arranged. The upper carbon-holder G is connected with the endless chain E, on the
left-hand side (Fig. 1), while the lower carbon-holder G₁ is connected with the said
chain on the right-hand side. The mode of connecting the carbon-holders with the
chain is illustrated in Fig. 4 and consists in fitting each carbon-holder with a bridge-
piece or block g into which is screwed a rod g¹; the latter being furnished with a
tang which passes through the longitudinal opening f (or f¹) in the pillar F (or F¹)
and through one of the links of the chain E₁. The carbon-holders are provided with
anti-friction rollers H with a view to facilitating their movement along the surface of
the pillars F F¹; the openings ff in said pillars permitting the said carbon-holders
to readily traverse the same by means of the tang on the screw g¹. The opening f¹
extends along the upper portion of the inner side of the left-hand pillar F1, while the
opening extends along the lower portion of the inner side of the right-hand pillar F.
The upper carbon-holder G is insulated from the rest of the mechanism of the lamp
by means of the washers J and ¹. The carbon is carried in a socket or sleeve I
(Fig. 3) separated from the metal part I¹ by a washer I111 of insulating material.
From the socket I a screw I¹¹ extends through, but out of contact with, the part G of
the carbon-holder; and the upper part of such screw enters a current-receiving post i
maintained out of contact with the part G by means of a washer or plate i of
insulating material. At the binding post i there terminates the conducting wire 1.
Consequently the current which arrives through this wire passes directly by way of the
screw to the upper carbon-holder without becoming diverted through the other
portion of the lamp mechanism. The lower carbon-holder G₁ is not insulated from
the mechanism of the lamp.
In view of the method adopted for connecting the carbon-holders G G with the
endless chain E₁, it will be readily understood that the motion of the chain in the
direction of the arrow 2 (Fig. 1) will have the effect of separating the carbon-holders
and consequently the carbons, and that when the said chain travels in the direction
of the arrow 3 (Fig. 1), the effect will be to cause the carbon-holders to approach each
other. The said carbon-holders are thus moved nearer together through the agency
of the clockwork operated by the spring barrel A. The opposite movement of the
carbon-holders-away from each other-when the lamp is being lighted, is brought
about by the starting electro-magnet K the windings of which-comprised in the
arc-circuit are traversed by a powerful current upon the contact of the carbon points
When this latter occurs, the electro-magnet K attracts its soft iron armature d
(Figs. 1 and 6) and the entire clockwork swings round upon its arbor as together

page_text: with the pinion E¹¹, which accordingly performs a slight rotary movement in the
direction of the arrow 4 (Fig. 6), with the effect that the two carbons are separated a
little distance, since the direction of such rotation corresponds to a movement of the
chain E, in the direction of the arrow 2 (Fig. 1). Normally, whilst the armature d is not.
attracted, the clockwork rests against an adjustable arresting screw, by which means
the amplitude of the oscillation of the clockwork may be varied and consequently the
initial length of the arc adjusted.
Further on we will describe the arrangement of regulator, which, when required,
arrests the clockwork or starts it, as the case may be but we will now describe the '
course pursued by the current as it flows through the lamp.
The current which enters the lamp by way of the wire held in the insulated
terminal or binding post L, as shown in Fig. 2, passes through the starting electro-
magnet K (Figs. 1 and 6) and wire 1 into the upper carbon-holder.
It then passes
through the lower carbon-holder into the lamp and leaves the same through the
post L' which is in electrical connection with the lamp.
As soon as the current has thus passed through the lamp, and while the upper
and lower carbons are touching, the electro-magnet K is traversed by a very powerful :
current, so that its armature d becomes attracted. The whole clockwork accordingly
oscillates on the spindle and the pinion E" moves slightly in the direction of the
arrow 4 (Fig. 6), such movement separating the carbons slightly and effecting.
the formation of the arc; whereupon the lamp comes into operation.
The means for regulating, hereinbefore referred to, are as follows:-On the
spindle is an oscillating flyer or pallet having at one end a stud (Fig. 7) so
arranged that, normally.e., while the lamp is in operation and the armature dis
being attracted by the starting electro-magnet K-it takes up its position between
two consecutive pegs or sprockets c of the wheel C, thereby checking any oscillatory
motion of the clockwork and maintaining the carbons at a uniform distance apart. ·
The other end of the pallet ¹ is located above the core M of the fine wire electro-
magnet M¹ which is connected in parallel with the main circuit; the said fine wire
coil being, to this end, connected by the wire 6 (Fig. 7) to the binding post M11
(insulated from the lamp) and thence to the wire 1; the wire 7, on the other hand,
connecting the said coil with the lamp.
When, as the result of the wear of the carbons, the resistance of the lamp increases,
the current passing through the electro-magnet M-in derivation or parallel-
increases in amount or amperage to such an extent that, the core M becomes
sufficiently magnetised to attract the pallet ", disengaging the stud 11 from the
sprocket-wheel; the clockwork thereupon revolving in a reverse direction to that
indicated by the arrow 4. Thus the carbons will be caused to approach each other,
and the moment the resistance met with by the current becomes normal again, in
consequence of the proximity of the carbons-i.e., when that degree of resistance is
restored to which the lamp has been set-the current in the parallel connection of
the coil M will decrease in amount and the pallet will be brought back to its
original position under the influence of the spring P which controls it and which is
shown in detail in Fig. 10. Thus the lamp will operate automatically, and continue
to regulate itself until the last stage of wear of the carbons is reached.
The arrangement for the control of the pallet simply consists of a spring P one.
end of which is secured to the spindle 7 and the other end to the casing P¹ the
rotation whereof effects the compression (more or less) of the spring P.
It will be understood that what should be first regulated in the lamp is precisely
he power which this spring P is to display in its action upon the sleeve or case P¹,
o as to obtain a length of arc corresponding with the current consumed.
From the foregoing remarks it will be clear that the operation of the herein
lescribed lamp-mechanism is independent of the law of gravitation and that our
amp may, in consequence, operate in any desired position; the only manipulation
ecessary, after the lamp has once been fitted in its place, being the exchange of the
arbons as they are worn away.
.
'

page_text: To substitute fresh carbons, it is only necessary to move the carbon-holders apart,
by hand, by pressing the one away from the other. As this operation is being per-
formed the ratchet A¹ will ride over the catch of the barrel A without engaging the
wheel B; and, owing to the movement thus imparted to the said barrel A, its spring
will be compressed to the extent to which it had been slackened during the pre-
ceding operation, with the result that the mechanism always remains in operative
condition.
Figs. 11 and 12 illustrate a modification of the regulating device whereby the
clockwork controlling the carbons is automatically stopped or started as the case may
be.
This modified form of regulator consists mainly of an armature R adapted to be
attracted by the core M of the electro-magnet M¹, such armature being subjected to
the action of a spring which tends to raise it. The tension of the spring ris
variable at will by means of a set-screw ¹.
The wire 7 instead of being connected as in the arrangement previously described
to the body of the lamp by means of the plate which supports the clockwork
mechanism, is here connected to a rod or screw 11 insulated from the plate 11.
Against the lower end of the rod or screw 11 rests a flat spring R¹ attached to the
upper side of the armature R. The elevation of the said screw r11 in relation to the
spring R which elevation is adjustable at will-is such that, normally-i.e., while
the armature R is not attracted by the core M-the spring R' touches the lower end
of the rod 1, while, in the event of the armature R being attracted by the core M,
the said spring R¹ no longer touches the said lower end of the screw 11
Hence a parallel circuit will be constantly maintained so long as too great a
resistance is not set up in the main circuit owing to the carbons being too far apart;
but the moment the resistance of the main circuit increases so that the amperage of
the current passing through the "parallel" circuit-and consequently through the
coil M¹ becomes greater (and so that the armature R is attracted by the core M)
the said parallel circuit is broken or opened, owing to the separation of the
spring R and red 11; the armature R thereupon resuming its initial position.
The end S of this armature is provided with a plate S' pivoted at S₁₁ to the
part 8. The position of the plate S¹ in relation to the sprocket wheel is such that,
normally while the armature R is not attracted by the core M-the free end
thereof enters between two consecutive sprockets c in the wheel C, thereby preventing
the rotation of the latter. When, however, as seen above, the armature R is
attracted by the core M, owing to the increase of current passing through the
"parallel or derived connection, the plate S¹, in consequence of the movement of
the armature R, turns on its pivot $11, in the direction of the arrow (Fig. 12),
and escapes from the sprockets c, thereby rendering the wheel C capable of
turning.
"
Thus the motion of the carbon-holders is regulated in a manner similar to that
previously described, with this difference however that the regulation is effected
in the present instance by means of rapidly succeeding jerks, the derived or parallel
circuit being opened every time the arinature is attracted.
The endless chain is preserved at the requisite state of tension by means of an
adjustable stretching roller T disposed at the lower end of the lamp, T¹ T" are
suspension rings.
Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed, we claim :-
1. The improved electric arc lamp constructed or operating substantially as herein
described and wherein the carbons are operated by clockwork mechanism in
conjunction with an electro-magnet inserted in the main lamp circuit between the
point of entry of the current and the upper carbon-holder and an endless travelling
chain or flexible connection; the said clockwork mechanism being capable of
oscillation so as to impart a slight rotary motion to the spindle whereon the spring-
barrel is mounted.

page_text: 2. In an electric arc-lamp, the combination with the mechanism.referred to in the
preceeding claiming clause, of a sprocket wheel operated rotatively by the clockwork
and capable of being arrested in its rotary movement by a vibratory plate, the latter
being attracted and disengaged from the said sprocket wheel by an electro-magnet
connected in parallel in the main lamp circuit, substantially as set forth.
3. In an electric arc-lamp, a chain or other endless flexible connection engaging
with or passing over a chain wheel or sheave mounted on the spindle of the spring-
barrel, and being conducted through the hollow pillars or supports while subjected to
the action of a stretching device; the tangs which connect the carbon-holders with
the chain traversing longitudinal slots forined in the said pillars, substantially as set
forth.
4. In an electric arc-lamp, a contact-breaker or switch arranged within the derived
or parallel circuit of the regulating electro-magnet, and adapted to automatically open
such circuit upon the passage of current; the said contact-breaker or switch consisting
of a spring which is secured to the armature of the regulating electro-magnet and
against which the extremity of a rod or screw makes contact so long as the said
armature is unattracted, substantially as set forth.
5. The improved electric arc-lamp having a fixed focus and being capable of
operating in any position with either continuous or alternating currents, constructed
substantially as described with reference to the accompanying drawings.