Improvements in Electric Arc Lamps.
Year: 1895

page_text: Date of Application, 8th Apr., 1895
Complete Specification Left, 10th Feb., 1896-Accepted, 4th Apr., 1896
Improvements in Electric Arc Lamps.
I, HENRY JAMES FISHER, of 102, Shooters Hill Road, Blackheath, in the
County of Kent, 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 objects to economise
the current required for automatically controlling and regulating the carbon
feeding mechanism, and to provide an arc lamp adapted for use at will with either
continuous or alternating currents.
33
According to my invention I am enabled in some cases to dispense altogether
with the use of solenoids in an arc lamp, and I use a novel and useful arrangement
and adaptation of the "heated wire system for automatically controlling the
carbon feed; I also use or may use the same system for striking the are; and in
carrying out my invention I arrange and combine the elements together in such
manner that economy both in first cost and in working conditions is attained, and
also other advantages accrue.
In constructing a lamp I employ (as has been previously employed) a rack
which holds the upper carbon into which a pinion gears. This pinion is mounted
upon a fixed bearing and is fast to the first of a train of wheels terminating in a
smooth wheel, upon which a brake acts, the whole feed mechanism being mounted
in a rocking frame centred upon the same fixed bearing as the said pinion. The
lower carbon is held suitably either upon the lower member of the lamp frame, or
for a focussing lamp it may be carried upon a moving bridge piece automatically
operated in any convenient manner. The lamp frame is completed in the usual
way, suitable insulation being provided where required. The adjustment of the
rocking frame is effected by means of springs or movable weights and regulating
screws.
According to my present improvements the above mentioned brake (which may
be a lever, band, cam, or other holding and releasing device of suitable kind) for
controlling the smooth brake wheel of the feed regulating mechanism, is operated
at the required times automatically by a heated wire arrangement of high resistance.
connected in shunt with the main circuit and contained in a casing mounted upon
and moving with the rocking frame. In this shunt arrangement one or more wires
is or are arranged in "series and suitably disposed, being preferably led from.
one terminal, to and fro, around or over barrels mounted in said casing and con-
nected to the brake, returning over said rollers or barrels to the other terminal
of the case, with proper insulations where necessary. This shunt offers a path
for the current other than through the lamp carbons, and its action is hereafter
explained.
"
Further according to my invention, for striking the are I employ a similar hot
wire arrangement, but of low resistance, which is in series with the carbon rods and
constructed and disposed as follows.
One or a number of wires of suitable kind and length is or are arranged in
parallel or in series as may be convenient, and enclosed in a case or otherwise.
The device is fixed to the lamp frame and also connected to the rocking frame
by a conductor of some and suitable resiliency (on the pinion side of the carbon
holding rack) in such manner as to normally counterbalance the whole rocking
arrangement.

page_text: The operation of my above described invention is as follows.
When the current is first switched on to the lamp. if the carbon rods are in
contact the current flows through the low resistance device and also through the
carbon rods, and as the wire lengthens under the heating action of the current the
rocking frame through the rack and pinion separates the points of the carbon roʻls
to the required distance and the arc is struck.
If when the current is switched on the carbon rods are not in contact, then a
small current flows through the high resistance shunt device, and as this wire
lengthens under the heating action of the current the brake is released allowing
the carbons to come in contact, then the action of the low resistance device and
balance frame as above described separates then to the required distance and so
strikes the arc.
As in use the carbon rods burn away the resistance between them increases, and
the adjustment is such that when this resistance has increased beyond a certain
point the current flowing through the high resistance shunt device increases and
heats same sufficiently to release the brake, allowing the top carbon rod to
approach the other by gravity gradually until the resistance between the carbon
rods is so reduced that the current flowing through the shunt wire device is also
reduced. Then the wire cools and shortens and the brake is again applied to the
wheel. As the carbon burns away this action is continuously repeated, and the
feed of the carbon rods is automatic and practically continuous.
Dated this 8th day of April 1895.
J. C. CHAPMAN,
Agent.
Improvements in Electric Arc Lamps.
1, HENRY JAMES FISHER, of 102, Shooters Hill Road, Blackheath, 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 electric arc lamps and has for its objects to economise
the current required for automatically controlling and regulating the carbon
feeding mechanism, and to provide an arc lamp adapted for use at will with either
continuous or alternating currents.
According to my invention I am enabled to dispense altogether with the use of
solenoids in an are lamp, and I use a novel and useful arrangement and adaptation
of the "heated wire" system for automatically controlling the carbon feed; I also
use the same system for striking the are; and, in carrying out my invention
I arrange and combine the elements together in such manner that economy both
in first cost and in working conditions is attained, and also other advantages
accrue.
I will fully describe my invention in reference to the accompanying drawings in
which
Fig. 1 illustrates a type of arc lamp with the carbon feed mechanism carried in
a balanced frame in which an arrangement of my invention is embodied, and
Fig. 2 is a plan of the wheel gear.
In constructing a lamp I usually employ (as has been previously employed) a
rack R which holds the upper carbon C into which a pinion gears. This pinion
is mounted upon a fixed bearing 6 and is fast to the first a of a train of wheels a, c, d,
terminating in a smooth wheel e upon which a brake B acts; the whole feed
mechanism is mounted in a rocking frame F centered upon the same fixed
bearing as the said pinion r. The lower carbon C¹ is held suitably either

page_text: upon the lower member 9 of the lamp frame, or for a focussing lamp it may
be carried upon a moving bridge piece automatically operated in any convenient.
manner. The lamp frame is completed in the usual way, suitable insulation being
provided where required. The adjustment of the rocking frame F is effected by
means of springs or movable weights such as W and regulating screws as at w, w',.
suitably arranged.
.
The above mentioned brake (which may be a lever such as illustrated at B, or
a band, cam, or other holding and releasing device of suitable kind) for controlling
the smooth brake wheel e of the feed regulating mechanism, is operated at the
required times automatically by a heated wire arrangement H of high resistance.
connected in shunt as shown with the main circuit and contained in a casing c
which is mounted upon and moving with the rocking frame F. In this shunt.
arrangement one or more metallic strips, wires, or conductors h, his or are arranged
in series and suitably disposed, being preferably led from one terminal h¹ of the
casing to and fro around or over barrels such as c³ mounted in said casing and
connected to the brake, returning over said rollers or barrels to the other
terminal of the case, and thence to circuit, with proper insulations where
necessary. This shunt device is connected by a suitably resilient connection b¹ to.
the brake B and offers a path for the current other than through the lamp carbons,.
and its action is hereafter explained.
In addition to the above, according to my invention, for striking the arc I
employ a similar hot wire arrangement L, but of low resistance, which is in series.
with the carbon rods C, C, and constructed and disposed as follows.
One or a number of wires or conductors l, l, of suitable kind and length is or are
arranged in parallel or in series as may be convenient, and enclosed in a case such.
as d' or otherwise. The device is fixed to the lamp frame as shown at a, and also.
connected to the rocking frame F by a conductor of some and suitable resiliency
(on the pinion side of the carbon holding rack R and at suitable distance from the
pinion centre) in such manner as to normally counterbalance the whole rocking
arrangement. From the frame F the current passes through the rack R and a
flexible conductor to the carbons. The above mentioned casings c¹ and d'
enclosing the wires may be perforated or furnished with valved apertures to provide.
for efficient and adjustable ventilation.
The operation of my above described invention is as follows.
When the current is first switched on to the lamp, if the carbon rods happen to.
be in contact the current from positive terminal P flows through the wires of the
low resistance series device L.and through the carbon rods C, C, and as the
wires lengthen under the heating action of the current the weighted end of
the rocking frame descends for a sufficient distance regulated by the screw w³, and
the movement of the pinion raises the rack and separates the points of the carbon
rods to the required distance and the arc is struck, the current flowing on to the
negative terminal N through the wire n.
If when the current is switched on the carbon rods C C' are not in contact, then
a small current flows through the high resistance shunt device H, and as the
wires thereof lengthen under the heating action of the current the brake B is.
removed from the wheel e, releasing the wheel work and allowing the carbons to
come in contact by gravity, then the action of the low resistance series device L.
and balance frame F as above described serves to automatically separate them to.
the required distance to strike the arc, when the brake is again automatically
applied.
As in use the carbon rods burn away the resistance between them increases, and
the adjustment is such that when this resistance has increased beyond a certain
point the current flowing through the high resistance shunt device H increases and
heats same sufficiently to release the brake B, allowing the top carbon rod C to.
approach the other by gravity gradually until the resistance between the carbon
rods is so reduced that the current flowing through the shuut wire device is also
reduced. Then the wire cools and shortens and the brake B is again applied to.

page_text: the wheel e. As the carbon burns away this action is continuously repeated, and
the feed of the carbon rods is automatic and practically continuous.
In some cases it may be advisable to provide supplementary means for assisting
and ensuring the proper application of the brake at required times as above set
forth in case its action might be too slow or otherwise insufficient; in such cases I
may employ a third and auxiliary hot wire device of similar construction to those
already described and of a resistance equal to or somewhat higher than that of the
low resistance L above described, and such auxiliary device I connect in shunt or
series upon the low resistance I and connect it to the brake B or it may be to a
supplemental brake acting on the feed mechanism in such manner that the brake
power will be sufficiently augmented and applied when the current is flowing
through the carbons.
By the use of my above described improvements also not only can the lamp be
used with either alternating or continuous currents as desired, but also much less
current is required in my shunt device than is required in the solenoids of lamps as
usually constructed, and thence more current is available for producing the light.
A further advantage is that the low resistance device L can readily be made of
such resistance that in lamps used on constant potential with continuous currents
the resistance coils usually necessary may be dispensed with, and where alternating
currents are employed the choking coils usually employed may also be dispensed
with. It will be evident that if desirable in any case instead of connecting the
high resistance shunt H across the lamp terminals as above stated it may be con-
nected in shunt with the carbon rods only. Also though I have above described a
rack and pinion arrangement of carbon feed I may employ any equivalent means
such as a drum with wound or weighted cord.
I do not confine my invention to any particular kind of arc lamp mechanisms,
and I would state that I am well aware that the use of wires or strips of metal
adapted to change their length when heated by a passing current and thereby
becoming a source of power transmission is not new, and to such principle 1
lay no broad claim nor to the use of the gear wheels and a brake controlling
same, but
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. In an electric arc lamp the use in combination of a plurality of sets of
hot wire devices of suitable resistances such as above described, the one adapted
to control the carbon feed, and the other to separate the carbons so as to
strike the arc, such actions occurring automatically and respectively at the times
required.
2. In an are lamp the combination with a hot wire shunt device such as H of
high resistance mounted upon and moving with a rocking frame carrying the feed
mechanism and adapted to automatically operate a brake controlling same of a hot
wire device such as L of low resistance in series with the carbons and adapted to
control the position of the said rocking frame and to strike the arc, the whole being
arranged or adapted to operate substantially in the manner and for the respective
purposes above set forth.
3. In an arc lamp the arrangement and combination of elements constituting my
invention as set forth in the preceding claims and as illustrated in the annexed
drawing.
Dated this 7th day of February 1896.
For the Applicant,
J. C. CHAPMAN,
70, Chancery Lane, London, W.C., Chartered Patent Agent.