Improvements in Automatic Electric Arc Lamps.
Year: 1892

page_text: Date of Application, 4th Aug., 1892
Complete Specification Lelt, 2nd Feb., 1893-Accepted, 18th Mar., 1893
PROVISIONAL SPECIFICATION.
Improvements in Automatic Electric Arc Lamps.
I, GEORGE HENRY CHURCH, of 31 Wrottesley Road, Plumstead, in the County
of Kent, Electrical Engineer, do hereby declare the nature of this invention to be
as follows:
-
My invention relates to certain new and useful improvements in the construction
of automatic electric arc lamps, and the main objects of the said improvements are
to simplify and cheapen the manufacture of such lamps.
My improved lamps are constructed substantially as follows:-
Two carbon holders are provided, to which the upper and lower carbons are
affixed, in any usual or convenient manner. The upper carbon holder is either
attached to a rack, gearing with a spur wheel, or pinion, or to a metal chain, band,
or other flexible conductor, running over a wheel, journalled in suitable bearings.
The said pinion, chain, or band wheel, has worm teeth, cut upon any convenient
part of itself, or a separate worm wheel may be employed, rigidly attached to it, or
its axis.
A shaft, having a worm gearing with the said worm wheel, is journalled in bearings,
at or near its extremities, in such manner that it is capable of longitudinal as well
as rotary movement in the said bearings. The amount of the longitudinal
movement is controlled by adjustable stops.
A ratchet wheel is fixed on the
worm axis and rotated by a pawl, operated by the keeper of an electro-magnet,
shunted to the are through the agency of a make and break contact; the
strength of current at which the latter will act being regulated by tension adjust-
ment. The make and break contact is not absolutely essential, as the keeper may
be operated by the difference in the strength of the electro-magnet, due to a longer
or shorter arc, as hereinafter described. When the said ratchet wheel is rotated
by the pawl, the top carbon is caused to descend. In place of the worm and
worm wheel, ordinary spur or bevel gearing may be employed, and any suitable
form of step by step device may be used, instead of the aforesaid ratchet and pawl,
as for example an arrangement similar to a clock escapement. In the latter case
suitably formed pallets, actuated by the keeper of the aforesaid electro-magnet
would be caused to rotate a suitably formed wheel fixed on the pinion, chain
or band wheel axis, or to act upon teeth provided on the said pinion, or wheel.
The action would be the reverse of a clock escapement, i.e. the pallets would
positively rotate the wheel instead of permitting to rotate intermittently.
The aforesaid worm shaft is acted on by a spring, tending to move it longi-
tudinally in one direction, and acting in opposition to the said spring is another
spring, or a lever forced forward by a spring, and controlled by an electro-magnet.
This latter spring or lever is stronger than the former, and consequently forces the
worm back against its tension to the stop limit.
When the carbons come together, and while an arc is established between them,
the main current passes through and excites the aforesaid electro-magnet, which is
placed in series with the carbons. The said magnet attracts a keeper, which pulls
over the stronger spring or lever and allows the weaker spring to come into action
and push the worm to the stop limit at the other end, this longitudinal movement
rotates the pinion, chain, or band wheel in the opposite direction to that in which
it is rotated, when the aforesaid ratchet wheel is rotated, and so causes the top carbon
to ascend thereby establishing an arc, or distance between the carbons.
The longitudinal movement of the worm, or the lever controlled by the electro-
magnet in series with the arc, may be arranged to operate any suitable form of
cut-out, which can either short-circuit the lamp, or put in a compensating resistance

page_text: equal to the arc itself, during the time the carbons are approaching each other, or
in the event of the lamp failing to act properly, so that any other lamp in circuit
with it would not be affected.
If preferred, a separate cut-out, in no way dependent upon the lever or worm
shaft before mentioned, may be employed.
Slip gearing, or any other suitable device may be provided, so that when the
lamp has run down and it is required to raise the top carbon holder for the purpose
of recarboning, the rack, chain, or band, to which the said holder is attached may
be pushed up without it being necessary to move any part of the lamp gear, other
than the pinion, chain or band wheel aforesaid.
In cases where focus keeping of the arc is desired, the upper carbon holder is
fixed to one end of the flexible conductor, as before described, but the lower carbon
holder instead of being a fixture, is attached to the other end of the said conductor,
which passes over the chain, or band wheel, and also over guide pulleys, when
necessary.
In this case the flexible conductor must be insulated from one or other of the
carbon holders. With this arrangement no slip gear will be necessary, for by
raising the upper carbon holder, the weight of the lower holder will cause the chain
or band to slip over the wheel, while the said wheel remains stationary.
In place of the said flexible conductor, two racks gearing with opposite sides of
a pinion may be employed, if preferred, each carrying a carbon holder.
When a chain or band is used, it will be kept taut by the weight of the carbon
holders at each end, and either in this arrangement, or with the double racks,
when the upper holder rises the lower one descends and vice-versa. This method
gives great facility for the rapid insertion of full length carbons.
The action of my improved lamp is as follows:-
Supposing the carbons to be separated, and therefore no current passing through
them, the electrical arrangements are such, that the strength of the electro-magnet,
which operates the pawl, or other equivalent device, is greater than when an arc is
established, because the coils of the said magnet, are shunted across the arc.
The keeper is therefore attracted against the tension of its spring, and in its
forward movement automatically breaks the electro-magnet circuit, the magnet
then loses its power, and the tension of the aforesaid spring pulls the keeper back
again. During such backward movement, it causes the pawl to rotate the ratchet
wheel and worm, at the same time the electro-magnet circuit is again closed, and
this operation continues until the worm has been sufficiently rotated to cause the
carbons to meet, and a current to be established between them. If preferred the
electro-magnet may be caused to rotate the ratchet wheel, and give the feed, while
the spring merely pulls the pawl back again over the teeth. When the current is
established between the carbons, the electro-magnet in series with the arc and
main circuit comes into play, attracting its keeper, and so permitting the weaker of
the two springs aforesaid, to longitudinally move the worm shaft and separate the
carbons to the required distance to establish an arc, as determined by the adjustable
stops before described.
As the carbons consume, and the distance between them increases, the current
through the electro-magnet coils, shunted across the arc, increases sufficiently to
cause the said magnet to again operate the step by step mechanism, and so make
the carbons approach each other. This approach causing a fall of potential across
the arc and a consequent diminution in the current through the electro-magnet
coils, renders the ratchet mechanism inoperative.
Such mechanism will however again be brought into play directly the are
lengthens through consumption of the carbons. The lamp will thus feed auto-
matically as the carbons burn and will maintain an approximately constant length
of arc throughout.
When the rack, chain, band, or other flexible conductor has travelled to its full
extent, so that the lamp can feed no farther, the are will lengthen till it goes out.
The electro-magnet in scries with the are will then lose the power of attracting its

page_text: keeper, as no current can pass through, and the release of this keeper permits the
stronger of the two springs, before mentioned, to come into action and force the
worm shaft to the opposite stop limit, at the same time short circuiting the lamp,
or inserting a compensating equal resistance, as before described.
Arrangements may be provided which will allow the pinion, or the wheel carry-
ing the flexible conductor, to be thrown out of gear with the rest of the lamp
mechanism and permit the said conductor or rack to descend till the carbons touch,
and when the main current passes through, it may be so arranged as to throw the
pinion or wheel into gear again.
When alternating currents are employed, or when advantageous for other reasons,
solenoids and iron cores, either solid or laminated, may be used in place of the
magnets and keepers, as described.
Dated this 4th day of August 1892.
AMBROSE MYALL,
21, Cockspur Street, London, S. W., Agent for the Applicant.
COMPLETE SPECIFICATION.
Improvements in Automatic Electric Arc Lamps.
I. GEORGE HENRY CHURCH, of 31 Wrottesley Road, Plumstead, in the County
of Kent, Electrical 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 certain new and useful improvements in the construction
of automatic electric arc lamps, and the main objects of the said improvements are
to simplify and cheapen the manufacture of such lamps, at the same time rendering
their action more reliable.
In the accompanying five sheets of drawings
Fig. 1 is a side elevation of an arc lamp constructed in accordance with one
method of carrying out my invention.
Fig. 2 is an end elevation of the ratchet and pawl mechanism, shewn in Fig. 1.
Fig. 3 is a side elevation of a modified form of the tape drum and tape shewn in
Figs. 1 & 2.
Fig. 4 is a diagrammatic representation of a modified arrangement of the
mechanism, adapted for lamps used in series.
Fig. 4 is a diagrammatic plan of part of Fig. 4.
Fig. 5 is a diagrammatic representation of another modified arrangement, adapted
for lamps used in series.
Fig. 5 is a diagrammatic view at right angles of part of Fig. 5.
Fig. 6 is an elevation of a form of clutch which may be employed in place of
certain parts in Figs. 4 or 5.
Fig. 7 is an elevation of a driving device which may be employed in place of the
ratchet and pawl arrangement shewn in Figs. 1 & 2.
Similar letters of reference denote similar parts throughout the drawings.
Referring first to Figs. 1 and 2, which give a general idea of the most usual form
in which I arrange my apparatus; A A are two vertical rods united at the lower
ends by a cross bar A' and having their upper ends fixed into a plate B, which
forms the base plate upon which the lamp mechanism is fixed. These rods A. A.
form the guides upon which the upper carbon holder frame C, aud the lower carbon
holder frame C', slide in the usual way. These carbon holders may be of any
usual or other desired form. D is a drum provided with flanges D', and capable of
rotating in bearings D².
It carries a flexible copper tape E, one end of the said tape is attached to the
upper carbon holder frame C, and the other end to the lower carbon holder frame C¹.
The bottom carbon holder is insulated from the carbon holder frame and body of

page_text: the lamp and connected to the insulated block on the cross bar A' by a flexible
wire f. That end of the tape which goes to the lower holder frame passes through
a clearing hole C2 in the upper holder frame and both ends pass through clearing
holes in the base plate B.
Affixed to the spindle D³ of the drum D, or to the drum itself, is a worm wheel F,
His a horizontal spindle having formed upon it, or affixed thereto, a worm J,
gearing with the worm wheel F.
This spindle H is capable of rotation in hearings in the brackets K K', it is also
capable of a small amount of sliding, or longitudinal motion in the said bearings.
The extent of this sliding motion is limited at one end by the shoulder H' abutting
against the bracket K and at the other end by the screw L. This screw is provided
with a lock nut, as shown, and is capable of adjustment so that the extent to which
the spindle H can slide may be regulated as required.
The worm J having a right hand thread, it is manifest that if it be rotated in the
direction shown by the arrow in Fig. 2, the drum D will be rotated in the direction
shown by the arrow M in Fig. 1. Such motion will cause the upper carbon holder C
to descend and the lower carbon holder C¹ to ascend, and the carbons when put in
the said holders will approach each other. Now if the spindle H be made to slide
in its bearings in the direction shown by the arrow in Fig. 1, the drum D will he
rotated in the direction shewn by the arrow N and the carbons will be caused to
recede from each other. The first of these motions is employed to bring the
carbons together when the lamp is to be started, the second motion is then employed
to separate them to the required distance to form an arc, and then the first motion
is again employed to feed them together as they burn away.
The following are the means shewn for automatically producing these motions
in the required manner.
The rotary motion of the spindle H is effected by a ratchet and pawl device,
operated by an electro-magnet wound to a high resistance and shunted across the
are, and provided with a make and break contact. P is a ratchet wheel affixed
on the spindle H. Q is a vertical lever fulcrummed at Q' and provided at its
upper end with a pawl Q³, pressed down by a spring Q, engaging with the teeth
of the wheel P. R R is an electro-magnet shunted across the are or lamp
terminals. The lower end of the lever Q forms the armature of this magnet and
it is provided with an adjustable make and break contact at S.
T is a spring tending to force the armature away from the poles of the magnet R
and to make contact at S.
The sliding motion of the spindle H is effected as follows:-
V is a coiled spring placed around the said spindle and tending always to push
the shoulder H' up to the bracket K. W is a vertical lever fulcrummed at W',
having its upper end pressed against the projecting end of the spindle H by means
of a spring X This spring is stronger than the spring, V, so that when the lamp
is not burning the position of the parts is as shewn in Fig. 1. i.e. the shoulder H¹
is pushed away from the bracket K and the other end of the spindle abuts against
the adjustable stop screw L. Y is an electro-magnet placed in series with the
arc, and the lower end of the lever W forms its armature.
The action is as follows; Supposing the carbons to be apart, and no current
passing through them, the electrical arrangements are such that the strength of
the electro-magnet R R (which as before stated is shunted across the arc) is
greater than when the arc is established, the armature Q is therefore attracted
against the tension of the spring T and this movement, besides pulling the pawl
back over a tooth of the wheel P, automatically breaks the electro-magnet circuit
through the contact at S thereby causing the said magnet to lose its power. The
spring T then pushes the armature back again, causing the pawl Q² to rotate the
ratchet wheel P and so move the drum D in a direction to cause the carbons to
approach, as before described. The contact at S having been re-established by
the backward movement of the armature, the above motions are repeated until the
carbous meet, and the main current in consequence goes through them. The

page_text: electro-magnet Y in series with the arc and main circuit, now comes into play,
attracting and holding the lever W, against the resistance of the spring X. The
spring V is then free to force the spindle H forward until the shoulder H' abuts
against the bracket K, and this motion, as before described, rotates the drum D in
the direction of the arrow N, separating the carbons sufficiently to form an are.
The extent of the movement is readily adjusted by the screw L. The tension
of the spring T is so adjusted that the shunt electro-magnet R R is not sufficiently
powerful to pull its armature far enough forward to break contact at S when the
arc has its normal length, but as the carbons consume and the distance between
them increases, the pressure across the ends of the shunt magnet coils goes up, owing
to the increased resistance of the arc, till a point is reached when sufficient current
will pass through the said magnet to cause it to attract the lever Q far enough to
break contact at S, when the step by step gear is rendered operative and feeds the
carbons together, as before described, until the resistance of the are and
consequently the pressure across it diminish sufficiently to weaken the said magnet,
so that contact will not be broken at S, when the said magnet will again become
inoperative. The lamp will therefore feed automatically, as the carbons burn
away, and will maintain the length of are approximately constant throughout,
without reference to the quantity of current in the arc circuit.
If preferred, the lever Q may be so arranged, with respect to the shunt electro-
magnet R R, that the lever when attracted by the said magnet rotates the ratchet
wheel P, while the spring T merely moves the pawl back over the next tooth of
the wheel.
The mechanism in connection with the series electro-magnet Y may also be
modified, by causing the end of the spindle H to project through a hole in the
lever W, and a collar being provided on the end of the spindle outside the lever,
when the said lever is attracted by the magnet, it will move the spindle
longitudinally and so pull the arc. In this case the springs V and X are not
required, but a spring is placed at the other end of the spindle between the worm .J
and bracket K, which, when the magnet Y is not in action, carries the spindle
back to the stop limit L and takes the lever W with it.
The movement of the lever W may serve to operate a cut out Z, which will
put in a resistance a, slightly in excess of that of the arc at its normal length, in
fact so proportioned that the lamp will feed, when the circuit through the carbons
is interrupted from any cause.
When the carbons touch, sufficient of the main current will go through the
series electro-magnet Y to attract the lever W, and break the contact of the
resistance circuit at Z and relight the lamp. Other lamps in series would therefore
not be affected through the failure of the feed mechanism etc., should the carbons
not come together, or be wholly consumed.
To insert fresh carbons in the holders, it is merely necessary to raise the top
carbon holder frame C, when the tape E will slide over the drum D, being dragged
over by the weight of the bottom holder frame C', which will fall to the bottom of
the guides and no ratchet and pawl or other equivalent device to allow the drum D
to rotate independently of the worm wheel F is necessary, though such device may
be employed, if desired. If the top and bottom carbon holders are approximately
balanced, as regards weight, there will generally be sufficient friction between the
tape and drum to insure their turning together, as the lamp feeds or pulls an arc,
but to prevent the possibility of slip at such times, a friction roller may be provided
pressed against the upper surface of the tape on the drumm, by means of a spring.
The modified construction of tape drum and tape shown in Fig. 3 is another
means of providing against the contingency of slip, and is more especially useful in
preventing slip when pulling an arc.
Ratchet shaped teeth are provided around the drum, and the tape has pieces c
attached to its underside to engage with the said teeth. By this means the tape
can only slide over the drum in the direction shewn by the arrow, being that
required to raise the top and lower the bottom carbon holder.

page_text: The main current enters the lamp at the body terminal d and passes through the
base B, bracket K, drum D and tape E to the upper carbon holder frame C, thence
through the carbons to the lower holder C', which is insulated by the block e.
From this lower holder, a flexible insulated wire f¹ leads to an insulated terminal
under the crossbar A¹ and thence through an insulated wire inside the guide rod,
to the series electro-magnet Y, and from thence to the insulated terminal g. h is
the cut out and resistance circuit, before described, and insulated from the
lamp at i.
In place of the flexible tape E and plain drum D, I may employ a metal chain
working on a sprocket wheel, or a spur wheel or pinion gearing with two racks,
one such rack being fixed to the upper and the other to the lower carbon holder.
In either of these cases slip gearing must be provided to the sprocket wheel or
pinion, to enable the carbon holders to be moved by hand, when it is required to
insert fresh carbons.
In cases where focus keeping of the arc is not necessary, the lower carbon holder
may be a fixture, the upper holder only being moved by a rack and pinion in lieu
of a drum.
In this arrangement if a rack and pinion be employed, slip gearing is necessarily
provided.
When a number of lamps are burning in series arrangements may be adopted
which will allow the pinion, or the drum carrying the flexible conductor, or the
wormwheel to be thrown out of gear with the rest of the lamp mechanism, and
permit the said conductor or rack to descend till the carbons touch, and when the
current passes through, it is caused to throw the pinion or drum into gear again,
while the use of a compensating resistance in connection with the cut out Z (Fig. 1)
is avoided. A modified arrangement to accomplish the above objects is represented
diagrammatically in Figs. 4 and 44, in which the shunt magnet, pawl and ratchet,
make and break device, brackets, lower part of lamp etc. etc., are the same as in
Figs. 1 and 2, but are omitted to avoid confusion. In this case the top carbon
holder C is made heavier than the bottom carbon holder C', the worm wheel F is
cut away on one side and a certain amount of sliding motion allowed to its
spindle D³, so that by sliding the said spindle the wheel F may be moved into or
out of gear with the worm J. A spring pressing against the end of this spindle
throws the wheel out of gear with the worm, as shewn. The other end of the
spindle which projects through its bearing, at the same time forces a keeper k away
from the poles of an electro-magnet l. When the said keeper is so forced away, a
spring m attached to it makes a contact at n, which short circuits the lamp.
is
The spring at its lower extremity, carries a metal crossbar insulated from it
and the body of the lamp, the function of the said crossbar being to short-circuit
the series electro-maguet Y, which pulls the arc, through contacts 99 and thereby
prevents it acting till the wheel F and worm J are put into gear by the electro-
magnet. The arrangement of the magnet Y with its short-circuiting bar P
shewn most clearly in Fig. 44. The action of the arrangement is as follows:-If
carbons be placed in the holders and no current be going through the circuit, the
tape drum D will rotate till the carbons touch, as the weight of the top holder
preponderates and the worm wheel and worm are forced out of gear by the
spring j.
The course of the current, as soon as it passes through the lamp, is as follows.
Entering at the terminal dit passes through the body of the lamp to the upper
carbon holder C, through the carbons, across the ends of the arc pulling magnet Y
by means of the bar p, and then through the coils of the magnet to the insulated
terininal g.
As the current passes through the magnet l it attracts its keeper k,
which forces the spindle D³ in the direction of the arrow, against the resistance of
the spring j. This motion puts the wheel F in gear with the worm J. The
spring is so adjusted, that as soon as the wheel and worm commence to go into
gear, the contacts are broken at q 9 and the distance between these contacts
increases until the wheel teeth are completely in gear with the worm thread, as

page_text: soon as contact is broken at 99 the current is deviated through the coils of the
magnet Y causing it to act and pull the arc in the manner previously described.
On reference to Fig. 1 it will be seen that if arrangements were not provided to
ensure the worm and wheel being in gear before the arc pulling magnet acted, the
worm shaft alone would be moved longitudinally, the worm wheel and tape drum
remaining stationary, consequently no arc would be pulled.
In the further modified arrangement for series burning, shown in Figs. 5 & 5^,
the magnet Y in series with the carbons, pulls the arc by attracting its keeper W.
The worm wheel F is not cut away, as in Fig. 4, but the worm J is thrown out of
gear therewith by the end H' of its spindle H being lifted by a spring r, the hole
in the bearing K being elongated to permit such motion. The vertical electro-
magnet, best shown in Fig. 5, by means of its keeper p short circuits the series
magnet Y.
When the lamp is at rest the spindle H is lifted by the spring r, so that the
worm Jis out of gear with the wheel F, and the keeper W is forced away from the
magnet by means of the spring V pushing the end of the spindle H against it.
When carbons are inserted, they meet through the greater weight of the upper
holder, as before described in reference to Figs. 4 and 4^, and when current goes
through the lamp, the magnet pulls down its keeper p against the tension of the
spring and puts the worm J and wheel F into gear.
The arc pulling magnet Y is prevented from acting until the said parts gear,
through being short-circuited across the contacts 79, but these contacts are
arranged to break by the downward movement of the keeper p, as soon as the
worm and wheel begin to gear. The magnet Y then comes into play and pulls the
in the manner before described.
arc,
In place of the wheel F being cut away on one side and sliding out of gear with
the worm J as shewn in Fig. 4, the arrangement illustrated in Fig. 6 may be
employed. In this case a toothed clutch s is fitted to the wheel F and a similar
toothed clutch s¹ to the drum D, the spindle I carrying the said drum and clutch
is capable of sliding and revolving within the wheel F, so that end motion of the
said spindle will cause the clutch teeth to engage or disengage and so lock the
wheel F to the drum D, or release it therefrom.
The clutch teeth are preferably pointed in form to ensure engagement in any
position.
The poles of the magnet 1, Figs. 5 & 5 may be so shaped and matters so
arranged that this magnet causes both the worm J to gear with the worm wheel F
and pull the arc as well.
I do not confine myself to the use of the ratchet and pawl arrangement previously
described in reference to Figs. 1 & 2, for feeding the carbons together, as any
suitable step by step mechanism may be employed for this purpose.
Thus in Fig. 7, I show an adaptation of a clock escapement, convenient for such
action.
The wheel takes the place of the ratchet wheel P and is provided with teeth or
pins u, projecting parallel to its axis. v is a lever fulcrummed at v' and provided
with pointed pallets w w', and actuated by a shunt wound magnet R with a make
and break contact, as before described.
The action is as follows; the spring a pulls the end of the lever up, so that the
pallet w descends and slides against one of the pins u, causing thereby a partial
rotation of the wheel t, in the direction of the arrows, till the centre of the pin at
the opposite diameter shall just have passed the centre of the pallet w¹, further
descent of the pallet is arrested by its wedging between two pins, or adjustable
stops may be employed to limit the play of the lever. As the arc gets longer
through the carbons burning away, the shunt magnet will increase in power, as
before described, and gradually pull down the lever till contact is broken at S, the
pallet w meanwhile partially rotating the wheel in the same direction as before,
when contact is broken at S, the spring again comes into play, and these motions
are repeated until the carbons are near enough to weaken the shunt current so that

page_text: It
contact is not broken at S when it will become inoperative as before described.
will be seen that this device acts in the contrary way to a clock escapement, i.e. the
motion of the pallets rotates the escape wheel, instead of the motion of the wheel
actuating the pallets.
It may be observed that in all the forms of slip gearing lamps described, where
the weight of the top carbon holder preponderates, it is advantageous to provide
pins in the tape druin, fitting holes in the tape, or to employ a chain and sprocket
wheel, or a pinion and racks to prevent all possibility of slip.
It is also advisable to insert a small resistance y between the insulated contact n,
and the insulated terminal g, see Fig. 4, as it tends to insure the maguet pulling
over its keeper k and breaking contact at n, when the carbons touch.
Under certain circumstances the shunt magnet R may be replaced by one wound
differentially, and when alternating currents are employed, or when advantageous
for other reasons, solenoids and iron cores, either solid or laminated, may be used
in place of the magnets and keepers, as described.
am aware that in certain forms of arc lamps, previously constructed, the carbon
holders have been suspended by a flexible conductor from a drum or wheel, also
that in other forms of such lamps a step by step mechanism operated by a shunt
electro-magnet with a make and break contact, has been employed to feed the
carbons together, and I therefore make no broad claim to either of these devices
per se.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what I
claim, is :-
1. In an electric arc lamp, a drum or wheel having one or both carbon holders
suspended therefrom by a flexible conductor, a worm wheel integral with said drum,
and a worm gearing with said worm wheel, so that rotation of said worm rotates
said drum in one direction to feed the carbons together, while longitudinal motion
of said worm rotates said drum in the opposite direction to separate the carbons
and form an arc, substantially as described.
2. In an electric arc lamp, a drum or wheel, one or both carbon holders suspended
therefrom by a flexible conductor, a worm wheel integral with said drum, a worm
gearing with said worm wheel, and rotated to feed the carbons by a ratchet and
pawl or other step by step device actuated by an electro-magnet or solenoid,
shunted across the arc with a keeper or core and make and break contact, substan-
tially as described.
3. In an electric arc lamp, a drum or wheel, one or both carbon holders suspended
therefrom by a flexible conductor, a worm wheel integral with said drum, a worm
gearing with said worm wheel and rotated to feed the carbons by a wheel t having
pins u, actuated by a lever having pallets w, w forming or attached to the keeper
or cores of an electro-magnet or solenoid, shunted across the arc, with a make and
break contact, substantially as described.
4. In an electric arc lamp, a drum or wheel, one or both carbon holders suspended
therefrom, by a flexible conductor, a worm wheel integral with said drum, a worm
gearing with said worm wheel and moved longitudinally to pull an are by a spring
allowed to come into play through the keeper of an electro-magnet or core of a
solenoid in series with the arc overcoming a spring or resistance normally opposing
said spring, substantially as described.
5. In an electric arc lamp, a drum or wheel, one or both carbon holders suspended
therefrom by a flexible conductor, a worm wheel integral with said drum, a worm
gearing with said worm wheel, and moved longitudinally to pull an arc by the
keeper of an electro-magnet or core of a solenoid in series with the arc said worm
being normally held by a spring opposing said keeper, substantially as described.
6. In an electric arc lamp, a drum or wheel, one or both carbon holders suspended
therefrom by a flexible conductor, a worm wheel integral with said drum, a worm
gearing with said worm wheel, said worm rotated to feed the carbons by a step by

page_text: step device actuated by an electro-magnet or solenoid shunted across the arc with
a make and break contact, and moved longitudinally to pull an arc through the
agency of an electro-magnet or solenoid in series with the arc, substantially as
described.
7. In an electric arc lamp, a drum or wheel, one or both carbon holders suspended
therefrom by a flexible conductor, a worm wheel integral with said drum, a worm
gearing with said worm wheel and moved longitudinally to pull an arc through the
agency of an electro-magnet or solenoid in series with the arc, and a contact made
by said magnet cutting out the arc and inserting a resistance when the lamp ceases
to burn, substantially as described.
8. In an electric arc lamp, a drum or wheel, two carbon holders suspended there-
from by a flexible conductor, the upper holder preponderating in weight, a worm
gearing with a worm wheel on said drum spindle, and having the teeth removed on
one side, said wheel moved out of gear with said worm by a spring allowing
carbons to meet and making a contact cutting out the lamp, and inserting a
resistance y and contacts at q q cutting out the arc pulling magnet, or solenoid
and an electro-magnet or solenoid with keeper k, in main circuit forcing worm
wheel into gear and putting carbons and are pulling magnet or solenoid into
circuit, substantially as and for the purpose described.
9. In an electric arc lamp, a drum or wheel, two carbon holders suspended there-
from by a flexible conductor, the upper carbon holder preponderating in weight, a
worm wheel integral with said drum, a worm gearing with said worm wheel and
lifted out of gear therewith by a spring making contacts at cutting out
the arc pulling magnet or solenoid and an electro-magnet or solenoid / in main
circuit putting worm in gear with worm wheel and breaking contacts at 9 9,
substantially as and for the purpose described.
10. In an electric arc lamp, a drum or wheel, two carbon holders suspended
therefrom by a flexible conductor, the upper carbon holder preponderating in
weight, a worm wheel, a worm gearing with said worm wheel, a clutch son said.
worm wheel and a clutch son said drum, substantially as and for the purpose
described.
11. In an electric arc lamp, a drum or wheel having ratchet shaped teeth b, two
carbon holders suspended from said drum by a flexible conductor having projec-
tions c fitting said ratchet teeth, substantially as and for the purpose described.
Dated this 2nd day of February 1893.
AMBROSE MYALL,
21, Cockspur Street, London, S.W., Agent for the Applicant.