Improvements in Electric Arc Lamps.
Year: 1892

page_text: Date of Application, 15th Nov., 1892-Accepted, 14th Jan., 1893
COMPLETE SPECIFICATION.
Improvements in Electric Arc Lamps.
I, FRITS HANSEN, of Leipzig-Reudnitz, Saxony, Germany, 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:-
This invention relates to an electric arc lamp in which the regulation of the arc
is effected by means of a pivoted electro-magnet which on an increase in the
resistance of the lamp circuit is caused by a stationary armature to turn on its pivot
to an extent corresponding to the increase of resistance and thereby release the
arresting mechanism which controls the movement of the carbons.
In an arrangement of arc lamp according to my invention, there is used in
conjunction with the pivoted electro-magnet a chain wheel around which the chain
or other suitable connection carrying the carbon holders runs. This chain wheel
is mounted to oscillate with the electro magnet, but is so connected therewith that
the point of its circumference where the chain carrying the upper carbon holder
runs off, lies exactly in the axis of oscillation of the electro magnet, so that during
the oscillatory regulating movement of the electro magnet with the chain wheel the
said point and consequently the carbon suspended therefrom will remain stationary,
and only the opposite part of the chain or connection (hereinafter referred to as
the chain) carrying the lower carbon holder will be moved according to requirement
so that the regulation of the arc will be effected by the movement of the lower
carbon alone.
The arrangement is such that the position of the arc is caused to remain
practically constant, which allows of the use of a small globe, so that an intense
illumination can be obtained.
A lamp according to this invention can be constructed either as a series lamp or
as a shunt lamp that is to say with the coils of its electro-magnet either in series
with, or as a shunt to, the arc.
I will now proceed to more particularly describe by way of example the
construction of a shunt lamp according to my invention referring for this purpose
to the accompanying drawings in which
Fig. 1 is a longitudinal section of the lamp with the cover of the regulating
mechanism removed.
Fig. 2 is a plan of the regulating device.
Figs. 3 and 4 are side elevations at right angles to one another of the lamp also
with the cover removed.
Fig. 5 illustrates diagrammatically the path of the current and the connections
for a shunt lamp.
Fig. 6 is a section; and
Fig. 7 is an underside view of a clamping device hereinafter referred to.
Fig. 8 illustrates the mode of connection when the lamp is constructed as a series
lamp.
The carbon holder 6' carrying the upper carbon a¹, is guided by means of the
projections c³, c², c³, c, on the two hollow rods d d to which is fixed the plate e
carrying the regulating mechanism. The upper carbon holder b' is suspended
from the part f¹ of the chain f which runs round the chain wheel g and from the
other part of which is suspended the lower carbon holder 6' with the lower
carbon a'. The lower carbon holder is carried by the rod 6 which is guided in
the hollow rod and has connected to it the cross piece b to which the carbon
holder proper is fixed. A small pulley b' mounted on the rod 6 ensures the

page_text: contact of the lower carbon holder with the hollow rod and serves at the same
time to guide the lower carbon holder in an easy and efficient manner.
The plate e is provided with two vertical lugs or extensions e¹ and e' on which a
frame is supported by means of knife edges h¹ and h². The connecting line of
these knife edges h¹³ intersects the vertical axis of the carbons at right angles.
In the cross pieces h³ h h h arranged at both ends of the frame h, there is supported
the horse shoe electro magnet i¹. Also in the two middle pieces h', h³, of the
frame there is supported a shaft k on which the chain wheel g runs loosely. The
chain wheel is mounted in such a position that the point g' where the part runs
off from the chain wheel g, is situated exactly in the point of intersection of the
vertical axis of the carbons with the horizontal axis of oscillation of the frame h
passing through the knife edges h¹ h*. The result of this is that on the oscillation
of the frame, this point gl and with it the part 1 of the chain with the upper
carbon holder, remains stationary and only the outer portion of the chain with
the lower carbon holder is raised or lowered according to the extent of the
oscillation.
On one side of the chain wheel g is mounted a pawl which engages in a ratchet
wheel arranged at the same side of the chain wheel and fixed to the shaft k.
The engagement is ensured by means of a spring g*..
On the shaft k is also fixed a toothed wheel which acts by means of a train of
wheels 1, 1, 12, 13, 14 upon a fly shaft m which carries a star or ratchet wheel m' with
which gears a pawl
n fixed on a lever n¹ journaled on a pin n that is fixed to the
middle piece 48 of the frame h, the said lever n' being guided by means of a fillet
or projection fixed on the other end of the said piece h³. The lever_rests
upon an eccentric disc n' adjustably fixed to the middle piece h³, so that the depth
of engagement of the pawl n in the star wheel m¹ can be accurately regulated.
On the plate e are secured two pieces o' o' to which the stationary armature o³ is
secured by means of screws o'. These screws are adjustable in vertical slots o*.
There is also connected to the plate e a stop p which, on the oscillation of the
electro magnet in the direction of the arrow 1 arrests the lever n' after the
electro magnet has turned through a predetermined angle, and thereby throws
the pawl n out of gear on the further turning of the electro magnet, whereupon the
upper carbon holder 6' can descend owing to revolution of the chain wheel g and
the train connected therewith being thus permitted.
To the plate e are fixed the two terminals. The former which serves as the
positive terminal is fixed to but insulated from the plate e and is electrically
connected with the carbon a¹ which is fixed to but insulated from the carbon
holder 6. The negative terminal is electrically connected with the plate e which
is electrically connected with the hollow rods d¹ d'.
8
From the terminal r¹ there leads a branch conductor s which forms the winding
of the two legs of the horse shoe electro magnet and the other end of which is
electrically connected to the negative terminal.
The path of the current is more clearly indicated in Fig. 5.
When the circuit of the lamp is not completed the end of the electro-magnet
turned towards the armature o³ is in the lowered position shown in Fig. 1, in con-
sequence of the preponderance of weight on this side of the axis of oscillation. The
frame then rests with the foot 10 on the plate e and the mechanism is arrested.
When the circuit of the lamp is completed and the carbons are not in proper
position for forming the arc, the current passes through the branch conductors;
the attraction between the electro-magnet and the armature then overcomes the
aforesaid preponderance of weight; the electro magnet partly turns on its
knife edge bearings the pawl n is thrown out of engagement, and the preponderance
of weight of the upper carbon holder 6' comes into action and causes the chain
wheel g to rotate in the direction of the arrow 2. The pawl g' carries the ratchet
wheel round with it and thus rotates the shaft k and thereby the whole train of
wheels,,,, P, 1ª, m². When the two carbons come into contact the current
passes chiefly through the main conductor, with the result that the preponderance
7

page_text: of weight causes the electro-magnet to immediately swing back into its original
position and move the lower carbon away from the upper carbon to a suitable
extent to strike the arc.
In the swinging back of the electro-magnet the star wheel m' is at the same time
arrested by the pawl n whereby the whole of the train of wheels with the
chain wheel g is brought to rest.
When by the burning away of the carbons the resistance in the main circuit
increases, a correspondingly larger current will pass through the shunt circuit and
the electro-magnet will become more strongly energised and again commence to
partly turn on its bearings thereby without altering the position of the upper
carbon 6, moving the lower carbon 6 nearer to the upper carbon 61, so that
equilibrium is again established between the resistance in the arc circuit and the
extent of oscillation of the electro magnet. In this manner a permanent and
extremely fine regulation is effected.
As the carbons continue to burn away the extent to which the electro magnet
will turn will gradually increase; the lever n' will ultimately bear upon the stop p;
and then on the further turning of the electro magnet that takes place consequent
on the increasing resistance in the arc, the star wheel m' will be released. Then by
the rotation of the chain wheel g the desired supplementary regulation at once takes
place, both carbons being moved nearer to each other in such a manner that the
electro magnet swings back again in consequence of the sudden decrease of
resistance in the main circuit, and the described operation of regulation begins
anew.
A. spring u fixed at one end to the frame h and at the other end to a movable
lever u serves to counter balance to a certain extent, the preponderance of weight
of the frame and electro magnet on one side of the axis of oscillation so that the
sensitiveness of regulation is not injuriously affected. The extent of oscillation of
the electro magnet to each side is limited by stops which in the case shown are
provided on the frame hat h' and h¹º.
and
In order to enable the lamp to be conveniently adjusted by hand when the
mechanism is covered, the stop p is fixed to a pin p¹ that is guided in a sleeve
extends through a suitable hole in the plate e so that by pushing up the pin p', the
pawl n can be disengaged.
As will be understood from the foregoing description the focus of the lamp is
maintained constant. This allows of the use of a small globe a¹, which in the
example shown rests on a holder t which is fixed at a suitable place to the two guide
rods and has in the centre an annular hollow space t'in which the lower
tabular extensions of the globe fits.
For the purpose of cleaning the globe or inserting new carbons, the carbon
holders are moved away from each other by hand in the usual manner, the chain
wheel g rotating in the direction of the arrow 3, and the pawl g' sliding backwards
over the teeth of the ratchet wheel k¹.
In order to enable the upper carbon a¹ to be readily and quickly inserted, and to
ensure a perfectly secure holding of the carbon itself, the clampind device shown in
Figs. 6 and 7 may advantageously be used. It consists of a bent leve o² one
arm of which works in a slot in the sleeve a* and a spring w that is fixed to the
carbon holder. This spring acts upon the arm ' of the lever which also serves as
a handle in such a manner that the other arm of the lever firmly clamps the
carbon in the sleeve a³.
In order to secure under all circumstances electric connection between the lower
carbon holder 6 and one or other of the guide rods d' or d', the carbon holder
can, as shown in Fig. 4 be connected with one of these rods by a thin copper strip z
BO arranged as not to hinder the movement of the carbon holder.
As hereinbefore stated the lamp can also be constructed as a series lamp for
coupling up in parallel. The regulating mechanism in this case is the same as in
the shunt lamp above described excepting that the stationary armature o³, as shown

page_text: in Fig. 8 is arranged below instead of above the electro-magnet which is wound
with thick wire instead of with fine wire through which the whole of the lamp
current flows. Also that portion of the electro-magnet lying behind the axis of
oscillation and away from the armature together with the attached mechanism is
in this case made preponderant in weight, which may be conveniently brought about
by a spring of suitable strength.
The current enters, as in the shunt lamp, at the insulated positive terminal, is led
by an insulated flexible conductor to the positive carbon holder, which is also
insulated whence it passes to the carbon rods. The current then passes to the
lamp frame and is led by a flexible conductor connected to the latter, thence to the
winding of the electro-magnet, and finally passes by a conductor, also flexible and
insulated, to the insulated negative terminal.
The spring u is of such strength that when the lamp is cut out, the rear end of
the electro-magnet is drawn in a downward direction, so that the ratchet mechanism
is released, and the carbon rods consequently move nearer together.
When the lamp circuit is completed and the electro magnet is thereby energised,
the latter swings downward at its front end owing to the attraction of the armature
situated beneath it, the pawl n coming into engagement at the commencement of
the motion, whilst on the further movement of the electro-magnet the negative
carbon holder 62, which was alone set in motion, moves down still further until the
arc is of normal length. During the working of the lamp the electro magnet
becomes weaker in proportion to the decrease of the current strength due to the
lengthening of the arc so that the spring u will draw the electro magnet further
and further away from the armature o and thereby effect the regulation until
finally on the continued moving back of the electro-magnet the ratchet mechanism
will be disengaged when both carbons will be moved nearer to each other. In
consequence of the increase of current strength in the electro magnet that will
then immediately take place, the latter will again swing towards the armature and
the normal length of arc be again established.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed I declare that what I
claim is :-
1. An electric arc lamp in which the regulation of the length of arc is effected
by means of a pivoted electro magnet having a fixed armature and a preponderance
of weight in front of or behind its axis of oscillation according as the armature is
arranged above or below the electro magnet when this is in its normal position the
arrangement being such that on a predetermined increase in the resistance of the
arc circuit taking place the electro magnet will by the establishment of equilibrium
between the preponderance of weight on one hand and the attraction between the
electro magnet and armature on the other hand, be caused to partly turn and
release the mechanism which controls the movement of the carbons and allow these
carbons to move towards each other substantially as herein described.
2. An electric arc lamp of the kind referred to in the preceding claim in which
the regulating mechanism comprising a chain wheel is arranged in a frame that
turns or oscillates in common with the electro magnet, and the chain wheel is
mounted in such a manner that the point thereof where the portion of the chain
carrying the upper carbon holder runs off, is located at the intersection of the
axis of the carbons with the axis of oscillation of the electro magnet so that the
movement of the lower carbon only will be directly produced by movement of
the electro magnet substantially as hereinbefore described.
3. In an arc lamp of the kind referred to in Claim 1, the arrangement of a stop
adapted to be operated from a point external to the cover or case enclosing the
regulating mechanism, for the purpose of releasing the ratchet mechanism that
limits the movement of the carbons substantially as hereinbefore described.
4. In an electric arc lamp having a constant focus, the arrangement of the

page_text: globe-carrier fixed to the guide rods of the carbon holders and formed with a
groove or recess to receive the lower tubular portion of a globe, the arrangement
being such that the globe can be removed by simply lifting it as described.
5. In an electric arc lamp, a clamping device for the upper carbon consisting of
a pivoted bent lever, one arm of which moves in a slot in the carbon-sleeve and is
pressed against the carbon by a spring that acts upon the other arm which serves
also as a handle as set forth.
6. My improved electric arc lamp constructed substantially as hereinbefore
described with reference to and shown in Figs. 1 to 5 inclusive, or modified
according to Fig. 8 of the drawings annexed.
Dated this 15th day of November 1899
F. HANSEN,
By L. W., per F. B.