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

page_text: Date of Application, 5th Dec., 1895
Complete Specification Left, 7th Sept., 1896-Accepted, 7th Nov., 1896
PROVISIONAL SPECIFICATION.
Improvements in or relating to Electric Arc Lamps.
I, HENRY JAMES FISHER, of 102, Shooter's 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 the automatic and continuous regulation of the carbon
feed in that kind of electric arc lamp wherein the feed is automatically effected by
a rack carrying the upper carbon holder and gearing with a pinion on a toothed
wheel (hereinafter called the "pinion wheel,") or on the first of a train of toothed
wheels controlling the upper carbon and operated by the electric current flowing
through one or more solenoids.
My improvement refers to the operation of this toothed pinion wheel, and
according to one arrangement I employ a straight rack of suitable length formed
on or attached to the armature core of the usual shunt solenoid as an extension
thereof and directly engaging the said toothed pinion wheel, and below the rack teeth
I form on the rack bar a flat" of suitable length whereby at times the gear is
disengaged as hereinafter shown.
When the current is switched on to the lamp in order to strike the arc, the
straight rack is raised by the action of the shunt solenoid out of gear with pinion-
wheel teeth and then by the continued rectilinear motion of the rack bar the
"flat" only is presented thereto, and the pinion-wheel is free to be rotated by the
weight of the upper carbon and its holder, and thus the carbons come together;
then the current in the shunt solenoid being diminished, the rack falls at once into
gear again with the pinion wheel which raises the carbon for a suitable distance
and the arc is struck.
"
The regulation of the feed as required is automatically effected as follows.
The shunt solenoid is of such resistance that as the carbon rods burn away, the
current flowing through the solenoid increases and raises the rack until the "flat
is again presented, and thus the pinion wheel is again free to move, the whole
mechanical operation being effected by the reciprocating rectilinear motion of the
solenoid core and rack bar only, and as and when required. In connection with
said rack extension I employ an adjustable stop device for regulating as
necessary the distance of descent of the rack and consequent proper separation
of the carbons; also for ensuring steady motion of the solenoid core and its
racked extension I employ or may employ a dash-pot situated adjacent to the said
extension and connected thereto. The true rectilinear motion of the rack is
assured if required by a suitable guide.
Or instead of a straight rack and "flat" such as described, equivalently I may
employ a lever connected to the solenoid core and carrying a pinion or segment
engaging the toothed pinion wheel and having a flat formed on its periphery or
edge; or for focussing lamps I may mount the said toothed wheel and its pinion
(which engages the carbon holder rack) in a frame balanced upon the pinion axle
and carrying also a train of suitable wheels gearing with the before mentioned
straight rack, or the segment connected to the said solenoid core; then I connect
the two carbon holders to the first gear wheel by a chain or equivalent passing over

page_text: same so that the two carbons will synchronously approach or recede as required
for the feed.
Dated this 5th dor of Danamban 1005
J. C. CHAPMAN,
Agent.
improvements in or relating to Electric Are Lamps,
HENRY JAMES FISHER, of 102, Shooter's 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 the automatic and continuous regulation of the carbon
feed of that kind of electric arc lamp wherein the feed is automatically effected by
a rack carrying the upper carbon holder and gearing with a pinion on a toothed
wheel (hereinafter called the "pinion wheel "), or on the first of a train of toothed
wheels controlling the upper carbon and operated by the electric current flowing
through one or more solenoids.
My improvement refers to the operation of this toothed pinion wheel, and in
describing same I will refer to the accompanying drawings in which Figures 1 and 2,
illustrate one arrangement wherein I employ a straight rack R of suitable length
formed on or attached to the armature core d of the usual shunt solenoid S as an
extension thereof and directly engaging the toothed pinion wheel P, and below the
rack teeth I form on the rack bar a "flat" F of suitable length whereby at times
the gear is disengaged as hereinafter shown. The circuit arrangements and all
the other elements forming the are lamp are arranged in the usual known manner
and the necessary insulation is provided where required.
The action is as follows: When the current is switched on to the lamp through
the conductor H, H', in order to strike the arc the straight rack R is raised by the
action of the current passing through the shunt solenoid S and turns the pinion
wheel P and causes the upper carbon C to descend. If the carbons are not
then in contact the continued upward rectilinear motion of the rack bar R brings
the "flat" F of the rack bar in front of the pinion wheel P, which is therefore
left free to be rotated by the weight of the upper carbon Ċ and its holder C₁
through rack C2 and thus the carbons touch: the path thus offered to current
through the carbon rods is of so much less resistance than the shunt solenoid S
that the current therein is diminished, and the core d and rack R falls at once into
gear again with the pinion wheel P operating same by its weight and raising the
upper carbon C for a suitable distance; and thus the arc is struck.
The regulation of the feed as required is automatically effected in similar manner
as follows. The shunt solenoid S being as is usually the case, of such resistance
that as the carbon rods burn away the current flowing through its coils increases
and serves to raise the rack bar R until the "flat" F is again presented, to the
pinion wheel P which is then again free to be rotated one or more teeth as described
allowing the upper carbon to descend, the whole mechanical operation being
automatically effected by the reciprocating rectilinear motion of the solenoid core
and rack bar only, and as and when required. In connection with the rack
extension R', I employ an adjustable stop device t' for regulating as necessary
the distance of descent of the rack and consequent proper separation of the
carbons; the adjustable stop is arranged in the form of a push rod sliding in
guide and passing out through the base plate A so that it may be operated to
raise the rack for inserting new carbons when required, also for ensuring steady
motion of the solenoid core d and its racked extension I employ or may employ a

page_text: dash-pot situated adjacent to the said extension and connected thereto; such an
arrangement is shown in Fig. 2 where the plunger d' of dash-pot D is attached
direct to an extension of the rack R which extension passes through the base of
the dash-pot and the supporting plate A of the lamp frame, and is also provided
with an adjustable stop t' this extension may also be used for raising the rack
when it is desired to renew the carbons. The true rectilinear motion of the rack is
assured if required by a suitable guide such as t¹.
Instead of the straight rack with extension and flat such as described, equivalently,
I may employ arrangements of curved racks or pinions such as are illustrated in
Figures 3, 4, 5 & 6."
In Fig. 3, a lever L is connected to the solenoid core d by pin n sliding in a
horizontal slot n¹ formed in an enlarged part of the solenoid core extension d. The
lever L is attached to and carries a pinion, curved rack, or toothed sector M
centered at L to the lamp frame and engaging the toothed pinion wheel P. The
sector has a flat F formed on its periphery or edge above the teeth as shown.
The action of this arrangement is similar to that above described in reference to
the straight rack; on the core d being attracted and raised the teeth of the sector M
are disengaged from and the flat F presented to the pinion wheel P, thus allowing
the carbon and holder to descend by gravity as before and the same in regard to-
the automatic feed.
In Figs. 4, 5 and 6, I show an arrangement wherein I mount the toothed sector M
and the pinion wheel P (which engages with the carbon holder rack) in a rocking
frame V balanced upon the pinion axle or an axle in the same line therewith.
In Fig. 4 the sector M having a flat F as before is shown as mounted in a rocking
frame V balanced upon the axle of pinion P or a lineable shaft. A lever L'
attached to or formed in one with the sector M passes through a flared aperture d¹
in the core extension d.
Figs. 5 and 6, show an arrangement wherein the pinion or sector M having a
flat is mounted in a rocking frame as in Fig. 4, but serves to release a train of
wheels carried in the frame and the sector is directly connected to the core
extension d by means of a lever L. In both these arrangements when the core
is attracted the rocking frame V is tilted and the sector M moved upon its centre and
its teeth disengaged from the pinion wheel W in the arrangement shown in Fig. 4,
and from the train of wheels in the arrangements shown in Figs. 5 and 6. When
the latter arrangement is used for a focussing lamp the carbon holders are
connected to a grooved pulley on the first gear wheel of the train, by a chain or
equivalent passing over same so that the two carbons will synchronously approach
or recede as required. Suitable stops such as V₁ V' are provided in both
arrangements to limit the movement of the parts.
It will be plain to those skilled in the art that; instead of a shunt solenoid
arranged as described herein in reference to the drawings, a series solenoid may be
readily substituted. This would modify the arrangement shown in that the
rack operating the pinion wheel would be placed on the opposite side of the
wheel P to that shown in Fig. 1, and the flat F would be formed above the rack
teeth instead of below, the action will be readily understood.
Having now particularly described and ascertained the nature of this iuven-
tion and the manner in which the same is to be performed, I declare that what I
claim is :-
1. In an electric arc lamp the arrangement in combination with the tooth pinion
wheel operating and controlling the carbon feed of a straight racked extension of
the solenoid core having a flat formed thereon whereby the feed is automatically
controlled and the arc struck substantially in the manner above described in
reference to the drawings.
2. The arrangement in combination with the pinion wheel P of curved rack with
flat, operated through suitable connection by the solenoid core substantially as and
for the purposes herein described in reference to Figures 3, 4, 5 and 6.

page_text: 3. The several arrangements of my improved mechanism for the automatic
regulation of arc lamps substantially as above described in reference to the
respective figures.
Dated this 5th day of September 1896.
J. C. CHAPMAN,
70 Chancery Lane, London, W.C., Chartered Patent Agent.