IMPROVEMENTS IN ELECTRIC ARC LAMPS
Year: 1885

page_text: I, WILLIAM JAMES MACKENZIE, of 73 John Street, Glasgow, Lanarkshire,
Practical Electrician, do hereby declare the nature of my said Invention for
IMPROVEMENTS IN ELECTRIC ARC LAMPS to be as follows:-
"
This Invention of improvements in electric are lamps is in part a development
of the Invention described in the Specification of Letters Patent granted to me and
dated 7th January 1882 No 95.
As in my previous Invention referred to, I employ a small electro motor as the
power for feeding together the carbons, but I arrange the motor to act in an
improved manner, and I use separate devices for striking the arc, for regulating
the feed and cutting the lamp out of circuit.
The one carbon is fixed in but insulated from the framing of the lamp, and the
other is fed towards it; after the arc has been struck; by means of an electro
motor carried in the lamp frame, and consisting of a solenoid, within which
reciprocates a soft iron core connected through levers to a pawl acting on a ratchet
wheel on a spindle on which is fitted a worm gearing into a wheel in gear with a
rack formed on the movable carbon holder. The core is kept normally out of the
solenoid by means of a spring, but is drawn into the solenoid on the passage of
sufficient current through its coils, the solenoid being in the main circuit, while
another circuit or shunt to this motor solenoid being alternately closed and opened
by a switch operated by the motor itself causes it to reciprocate and so feed the
carbons together. In a shunt to the main circuit through the arc is a solenoid of
high resistance provided with an iron core whose extremity is formed with a point
dipping into a cup of mercury on the lamp frame but insulated from it. There is
a circuit through this point and cup which is a shunt to the motor solenoid, and
which circuit when closed weakens the motor current sufficiently to prevent its
working. The core is suspended by a spring the tension of which is regulated by
a screw or similar device; and the resistance of the solenoid in relation to the
tension of the spring is such that when the length of the arc is normal, the solenoid
core rests with the point in the cup, but when the normal length is exceeded a
larger proportion of the current passes through this solenoid causing it to act on
the core and raise its end out of the mercury, and by breaking that circuit to
strengthen the current through the motor sufficiently to make it work and feed
forward the movable carbon. After the arc is shortened to the normal length the
solenoid core again dips into the mercury and so short circuits the motor.

page_text: The striking of the arc is effected by a third solenoid or electro-magnet which is
in the main circuit, and whose core or armature is attracted when the carbons
touch and the current passes through them. The core is connected through a lever
or levers to and operates on a sliding or rocking frame carrying the feeding wheel
which engages with the rack of the movable carbon holder or with the spindle
carrying the feeding worm, and the motion of the core or armature by raising the
feeding wheel between the rack and worm raises the carbon holder with its carbon
sufficiently to strike the arc. The feeding wheel is mounted on a movable frame
sliding or rocking in the lamp frame, and when the circuit is broken, the frame
falls sufficiently to let the carbons touch or till it disengages the feeding wheel
from the worm so that the carbon holder drops by its own weight until the carbons
touch. The striking solenoid on the circuit being remade then raises the frame
with the feeding wheel into gear with the worm and rack, and thereby separates
the carbons to re-establish the arc. A cut out arrangement is provided worked by
the striking solenoid, by which the current passes when from any cause the circuit
through the carbons and arc is broken.
In the arrangement described, which may however be varied, the current passes
first from the positive terminal, partly through the motor and occasionally partly
through the switch and mercury cup, to the lamp framing thence by the carbons
and a conductor to the striking solenoid and negative terminal also partly through
the shuut; or second through the cut out to that terminal.
I also combine two or more pair of carbons and carbon rods in one frame,
employing the same feeding, striking, and regulating devices.
Dated this Fifth dox of Fahnuary 1985
W. R. M. THOMSON & Co.,
For the Applicant.

page_text: I, WILLIAM JAMES MACKENZIE of 73 John Street, Glasgow, Lanarkshire,
Practical Electrician 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 of improvements in electric arc lamps is in part a development
of the invention described in the Specification of Letters Patent granted to me and
dated 7th January 1882 N° 95.
As in my previous invention referred to I employ a small electro motor for
feeding together the carbons, but I arrange the motor to act in an improved
manner, and I use separa'e devices for striking the arc, for regulating the feed and
for cutting the lamp out of circuit.
My invention is illustrated by the accompanying drawings in which figure 1, is
an elevation of an electric arc lamp embodying my improvements, and figure 2, is a
sectional plan of the same the section being taken at the line 1-1 in figure 1.
The lamp framing A, is of any ordinary type and is provided with a horizontal
disc or plate A¹, which serves to carry the several operating parts of the lamp. The
one carbon B, is fixed in a clamp in the lower part of the lamp framing which is
insulated from the main part and the upper carbon B¹, is fed towards it, (after the
arc has been struck) by means of an electro motor carried in the lamp frame and
consisting of a solenoid C, within which reciprocates a soft iron core C¹, connected
through levers D, D¹, to a pawl e acting on a ratchet wheel E, on a spindle F, on
which is fitted a worm f, gearing into a toothed wheel G, on whose carrying spindle
is a pinion G', in gear with a rack formed on the movable carbon holder H. The
core C, is kept normally out of the solenoid by means of a spring C³, connected to
it, but is drawn into the solenoid on the passage of sufficient current through its
coils, the solenoid being in the main circuit as indicated by the connecting
wires w, w, while another circuit x, x, or shunt to this motor solenoid C being
alternately closed and opened by a switch I, I, operated by the motor itself
through the arm and the pins d, d, on the link D, causes the core C₁ to
reciprocate and by its action on the pawl e, ratchet E and gearing f, G, feeds the
carbons together. In a shunt y, y, to the main circuit through the arc is a
solenoid J, of high resistance provided with an iron core J, whose lower extremity
is formed with a point j, dipping into a cup K of mercury on the lamp frame A,
but insulated from it. There is a circuit through this point j and cup K which
is a shunt to the motor solenoid C and which circuit when closed weakens the
motor current sufficiently to prevent its working. The core J¹ is suspended by a
spring J the tension of which is regulated by a screw J³ or similar device; and
the resistance of the solenoid J in relation to the tension of the spring J is such
that when the length of the arc is normal the solenoid core rests with the point j
in the cup K but when the normal length is exceeded a larger proportion of the
current passes through this solenoid J causing it to act on the core J¹, and raise
its end out of the mercury, and by breaking the circuit z, z to strengthen the current
through the motor C sufficiently to make it work and feed forward the holder H

page_text: carrying the movable carbon B¹. After the arc is shortened to the normal length
the point of the solenoid core again dips into the mercury cup and so short-
circuits the motor.
The striking of the arc is effected by a third solenoid L or an electro magnet
which is in the main circuit a, a, and whose core 7 or armature is attracted where
the carbons B, B', touch and the current passes through them. The core is
connected through a lever M to the worm f which is fitted to slide upon its
spindle F and the motion of the core 1 by raising the worm f, into the position
shown in the drawing, causes the wheel G and pinion G¹, to turn and by acting on
the rack to raise the carbon holder H sufficiently to strike the are. When the circuit
is broken the weight of the worm f and carbon holder H overcomes that of the
core, and the worm f and the carbon holder H fall until the carbons touch. On
the circuit being remade the striking solenoid L attracts the core 1, raises the
worm fand the carbon holder and thereby separates the carbons to reestablish the
arc. A cut out arrangement may be provided worked by the striking solenoid, by
which the current may pass when from any cause the circuit through the carbons
and arc is broken.
In the arrangement described, which may however be varied, the current passes,
first, from the positive terminal P partly through the motor and occasionally
partly through the switch and mercury cup to the lamp framing A thence by the
movable carbon B¹, lower carbon B, and a conductor a to the striking solenoid L
and negative terminal N, also partly through the shunt; or, second, through the
cut out to that terminal.
I may also combine two or more pairs of carbons and carbon rods in one frame
employing the same feeding, striking and regulating devices.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed I declare that what
I claim is
(1.) The combination of parts constituting the improved electric arc lamp herein
described and illustrated.
(2.) In an electric arc lamp the arrangement of a reciprocating electro-motor and
actuating gear adapted to feed forward the movable carbon holder substantially as
herein set forth.
(3.) In an electric arc lamp the arrangement of the striking solenoid or electro
magnet acting through suitable gearing on the movable carbon holder to strike the
arc substantially as herein set forth.
(4.) In an electric arc lamp the arrangement in combination with an electro
motor serving to feed forward the carbons of the high resistance solenoid adapted
to short circuit such motor and prevent feeding when the arc is of normal length
substantially as herein set forth.