Improvements in or relating to Electric Arc Lamps.
Year: 1895

page_text: Date of Application, 20th May, 1895
Complete Specification Left, 20th Feb., 1896-Accepted, 21st Mar., 1896
Improvements in or relating to Electric Arc Lamps.
I, ALBERT LEWIS DAVIS, of 68, Victoria Street, Westminster, in the County
of London, Electrical Engineer, do hereby declare the nature of this invention to
be as follows:-
My invention relates to electric arc lamps, and has for its object to provide
simple, effective, and reliable means for automatically regulating the feed of the
carbons as and when required.
In carrying out my invention I adapt to my purpose the principle that when an
electric current is passed through two coils adjacently disposed, the said coils will
tend to move into a position such that their polar axes coincide and neutralise, and
I so combine together the parts of the apparatus as to efficiently serve the purpose
of an automatic feed regulator.
To this end I fix in a convenient position in the lamp two or more coils with or
without iron cores; at least one of these coils is movable, and in connection with
this movable coil or coils I fix a pinion, friction wheel or other suitable driving
wheel having a flat or inoperative part on its periphery; this wheel engages another
wheel connected with or giving motion to the carbon holders, any intermediate gear
being used if required.
The position on the pinion of this flat or inoperative part is such that when the
polar axis of the coil to which it is attached is at right angles to that of the other
coil or coils, the flat is presented to the other or driven gear or friction wheel,
which is consequently disengaged.
In connection with the movable coil to which the pinion is attached I arrange a
spring (or other suitable device, or the action of gravity may be equivalently
adopted,) in such a manner that it tends to keep the polar axis of this coil at right
angles to the polar axis of the other coil or coils so that the flat on the pinion is
presented to the other wheel.
The action of this regulator is as follows:-
When no current is passing through the lamp, the two wheels being disengaged,
as explained above, the carbons run together by the action of gravity, a spring or
other device.
When the lamp is put in circuit with the carbons in this position, the current
which passes largely exceeds the normal, and so turns the movable coil that it not
only brings the operative part of the pinion into gear with the driven wheel, but also
causes the latter to rotate in a direction tending to separate the carbons from one
another; so soon however as this separation of the carbons has reduced the current
to the normal current for the lamp, the action ceases owing to the attractive force
between the coils being exactly balanced by the tension of the said spring or other
equivalent device adopted. Owing to the consumption of the carbons and the
consequently increased resistance of the arc, the current gradually decreases in
strength, and the pull of the coils is overcome by the tension of the above named
spring or other device which gradually turns the movable coil and pinion driving
the other wheel and slowly feeds the carbons together; when however the coil and
pinion have been turned through a certain angle the flat or inoperative part of the
pinion approaches the other wheel and further motion of the carbons towards each
other is caused by the gradual slip of the driven wheel against the edge of the flat

page_text: on the pinion; the time and amount of such slip being determined by the decrease
in current through the coils caused by the consumption of the carbons in the lamp.
In the event of any excess current passing through the lamp owing to over
feeding of the carbons, defective carbons or other causes, the arc is lengthened
and the current again reduced to the normal by means of the action first described.
Dated this 20th day of May 1895.
J. C. CHAPMAN,
Agent.
4
"
Improvements in or relating to Electric Arc Lamps.
I, ALBERT LEWIS DAVIS, of 68, Victoria Street, Westminster, in the County
of London, 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 electric arc lamps, and has for its object to provide
simple, effective, and reliable means for automatically regulating the feed of the
carbons as and when required.
In carrying out my invention I adapt to my purpose the principle that when an
electric current is passed through two coils adjacently disposed, the said coils will
tend to more into such a position that their polar axes coincide and neutralise, and
I so combine together the parts of the apparatus as to efficiently serve the purpose
of an automatic feed regulator.
To this end I fix in a convenient position in the lamp two or more coils with or
without iron cores; at least one of these coils is movable, and in connection with
this movable coil or coils I fix a pinion, friction wheel, or other suitable driving
wheel, having a flat or inoperative part on its periphery; this wheel engages
another wheel connected with or giving motion to the carbon holders, any
intermediate gear being used if required, the details and operation being hereinafter
fully set forth.
I will now describe my invention in reference to the accompanying drawings
in, which
Fig. 1 shows the general arrangement of the lamp mechanism,
Fig. 2 shows a side elevation of movable coil and the gear wheels,
Fig. 3 is an enlarged front clevation of the gear wheels, and shows more clearly
the flat or inoperative portion of the gear wheel F.
Similar letters refer to similar parts, and it is to be understood that for the parts
of the lamp other than those claimed as of my invention any alternative
arrangement may be substituted.
C C' are the movable carbon holders, the top holder C being weighted as shown
at A. These holders are shown as suspended by means of a chain or flexible cord c
passing over a grooved pulley P, the axle of which is carried in bearings p.
W is
the main wheel which may be a toothed wheel, but I prefer to use a friction wheel
with or without the addition of a surface of compressed paper, leather, rubber, or
other suitable material to aid the surface friction; it is adapted to move with the
· carbon holders, being as shown for example fast upon the same spindle as the
pulley P, and if desired intermediate gear may be used. At the correct centres
from the wheel W and mounted in bearings p so as to be capable of gearing
therewith is another wheel F of the same kind, toothed or friction, as the case
may be.
This wheel F has a flat or inoperative portion formed on its circum-
ference as shown at O, and the portion of the circumference where the flat portion
meets the circumference of the wheel is gradually backed off,so as to avoid sharp
angles and to allow of the gradual gearing and equally gradual disengaging of the
wheels F and W. .

page_text: In connection with the wheel F and giving motion to it through the medium of
suitable gearing, but preferably mounted on the same spindle with the wheel F and
moving with it, are one or more coils, solenoids, or equivalent electric device M of
insulated wire with or without iron cores, but in order to reduce the size of the
mechanism and to obtain the maximum power in the smallest space, I prefer to use
iron cores in the movable coil or magnet M.
or
In proximity to this movable solenoid or magnet is fixed another coil
coils T T T T¹ with or without iron cores. The exact shape of these coils T T¹ is
immaterial; I prefer however to make them of an annular shape without an iron
core and the central space receiving the movable coil or core M as shown at the
broken part of Fig. 1.
The electrical connections and windings of both the fixed and movable coils or
magnets T T and M may be of any of the well known types, such for instance as
plain series, differential, or shunt, according to whether it is desired to control the
carbons by the current or by the pressure in the circuit. I prefer however to arrange
the windings of the inner or movable coil M as a shunt or divided circuit across the
windings of the outer coils T in such manner that only a small percentage of the
main current passing through the circuit traverses the windings of the inner or
movable coils M. The current may be led into the movable coils M by any
suitable flexible connection or by insulated contacts fixed to the movable coil
spindle and having brushes pressing and in contact with the movable contacts as
indicated in Fig. 2 at m m, or by other suitable device.
In connection with the movable coil and spindle or attached to the wheel F is a
weight B or other suitable device, such for instance as a spring, tending in the
case of a plain series or a differentially wound lamp to bring the flat or inoperative
portion of the wheel F into such relation with the wheel W that the two gears
tend to disengage.
A stop S is fixed on any convenient portion of the lamp frame or bearing
standard for the purpose of limiting the amount of the movement in either direction
of the movable coils M and wheel F; when for instance the spring or weight B
brings the wheel down into the position shown in Figs. 1, 2 and 3 the inoperative
portion of the wheel F comes into a position such that the two wheels F and W
are completely disengaged, and therefore the carbons are free to come into contact ;
if however through the powerful mutual action of the fixed and movable coils when
energised by the passage of a current of electricity in excess of the normal (such
for instance as occurs at the moment when the lamp is first switched into circuit)
then the stop S arrests further upward motion of the movable coils and wheel F
and therefore also of the wheel W, and the danger of the carbons becoming
separated by too great a distance to form a stable arc is by this means obviated.
In the event of the lamp being required for use as a plain shunt lamp in place of
the series or the differential type, then the action of the spring or weight B must
obviously be the reverse of that described above; that is, instead of tending to
disengage the two wheels F and W the action of the weight or spring must be to
tend to engage the gears and separate the carbons to the full extent, when the lamp
is out of circuit; and in this case, when it is required to place fresh carbons in the
lamp, the carbon holders are released from the gears by an auxiliary hand release
of any convenient form.
The action of the series and differentially wound lamps are somewhat similar and
may be described as follows.
When the lamp is out of circuit, the wheels W and F are by the action of the
spring or weight B out of gear, and the carbons therefore fall into contact through
the action of gravity, a spring or other device.
If now the lamp be switched into circuit the mutual action of the fixed and
movable coils T, T' and M causes the carbons to be separated to the normal
amount; directly however the mutual action of the coils T T¹ and M lessens
through the burning away of the carbons, the action of the spring or weight B in
conjunction with the downward pull of the weight A causes the movable coil and

page_text: wheel F to slowly turn in the reverse direction to the first motion, thus allowing
the gradual approach of the carbons; this continues until the backed off portion of
the Hat O approaches the circumference of the gear or friction wheel W, when
further approach of the carbons takes place by the gradual slip between the backed
off portion of the wheel F and periphery of the wheel W.
In the event of the carbons approaching each other to a distance less than the
normal, then the mutual action of the fixed and movable coils M and T T¹ over-
comes the action of the spring or weight B and the action of the weight A, and the
carbons are again separated until the normal distance is obtained, when the same
action takes place as first above described.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed, I declare that what I
claim is :-
-
1. The employment in an electric arc lamp for automatically regulating the feed
of the carbons as and when required, of an electro-magnetic controlling device in
combination with the special kind of feed and gear wheels, arranged or operating
substantially as described in reference to the accompanying drawings.
Inore
2. The improved automatic regulating apparatus comprising two or
adjacently disposed coils with or without iron cores, one of said coils being movable
and adapted to drive and control the position of a gear wheel F having a flat ()
formed as specified in suitable position upon its periphery, and a motion limiting
device, said wheel driving a second wheel W directly or indirectly through suitable
gearing connected with and controlling the movements of the carbons, the whole
being arranged or adapted to operate substantially in the manner and for the
purposes hereinabove described.
3. The use in an automatic carbon feed regulating apparatus such as is above
referred to of the two wheels F and W herein specified, the driving or feed wheel F
having a flat O formed on its periphery, and adapted to release or engage and
operate the driven wheel W at the times and in the manner hereinabove
described.
4. The improved arrangement for automatically regulating the carbon feed in arc
lamps herein before described and illustrated by the drawings.
Dated this 20th day of February 1896.