Improvements in or in connection with Arc Lamps.
Year: 1896

page_text: COMPLETE SPECIFICATION.
Improvements in or in connection with Arc Lamps.
I FRANK MICHAEL LEWIS of 34 Leinster Gardens Hyde Park 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 :-
This invention refers to details in connection with the construction and running
of are lamps, and is hereunder described with reference to the accompanying
drawings, which are added for the sake of illustration.
My invention in the first place comprises improvements in the governing or
regulating devices of arc lamps, which are illustrated in Figs. 1, 2 and 3 of the
accompanying drawings; Fig. 1 being a side elevation, Fig. 2 an end elevation
and Fig. 3 a plan. The chain or cord to the ends of which the carbon holders are
attached, passes round the toothed pulley a, mounted loose on the fixed axle b; the
ends of the latter being fitted in bearings forined in the hanging brackets c.
carbons are fed together by gravity, i.e. by the superior weight of the top carbon
holder or carrier.
The
On the same axle and secured to the pulley a is mounted loose the ratchet or
escapement or friction grip wheel d. In the same brackets c are formed the
bearings for a fixed axle e, which carries a two armed lever f; one side of which
is attached by means of a fork and pin to the core g of a solenoid. The opposite
side of the lever fis bent or otherwise formed with a foot h, provided with a hinged
pawl i; the back of which is pressed by a spring j, tending to force the opposite
end into gear with the wheel d. The motion of the pawli with respect to the foot h
is limited by the projecting stop piece k on the foot h, so that when the foot his
drawn back or raised sufficiently by the movement of the lever f, the pawli comes
out of gear with the wheel d owing to the different positions of the fulcrum of the
lever and the centre of the wheel d, and allows the latter and the pulley a to
rotate, i.e. the carbons to feed or approach each other.
The lever is mounted on a separate axle to the wheel d and pulley a, and by
means of the L shape of the lever and foot h, the pawl i is arranged to engage
with the wheel d diametrically or about diametrically opposite the fulcrum or axle
of the lever.
The action of the lamp regulating device just described is as follows:-
When no current is flowing, the core g is in its lowest position, and the lever f
is then in that position in which the pawli is clear off the wheel d, allowing the
carbons to be brought together by gravity. When the current is switched on, the
core is raised, and the lever f by means of the pawl i rotates the wheel d, and thus
separates the carbons, striking the arc. As the carbons are consumed, the core g
falls and keeps the length of the electric are constant by allowing the wheel d to
rotate slightly by gravity; and when the core is nearly at its lowest position, it
releases the wheel d, allowing the carbons to slightly approach, when the pawl
again re-engages. These operations are repeated throughout the running of the
lamp.
The above mentioned arrangement of the diametrically opposite positions of the
fulcrum of the lever f and the small arc of contact of the pawl i and the wheel d,
along with a horizontal position of the lever f, and of the line joining the axles b

page_text: and e, may be obtained by forming the fulcrum of the lever f in a projecting
bracket formed on the lever f, and lettered :h in Fig. 4; which illustrates this
arrangement. In this arrangement the core pulls in the reverse direction.
The piston of a dash pot may be connected to the lever f by means of links / see
Figs. 1 and 4.
The screwed end m of the lever f Fig. 1 serves to carry a tapped weight for
adjustment purposes.
In the second place my invention refers to a new or skeleton form of holder or
bucket for carrying the solenoid of an arc lamp. This is shewn in vertical section
in Fig. 5, (the solenoid being indicated only on the left side by section lines,) and
in horizontal section in Fig. 6. This consists of an upper rim or ring n, provided
with an outside horizontal flange o for attaching it to the dome or top of the lamp
carrier, and a lower rim or ring p, having a very wide internal flange q; the two
rims or rings n and p being connected by means of three (or more) narrow vertical
bars r. The fewer the bars the better. The. bottom of the solenoid is carried by
the bottom internal flange g, annular discs of porcelain, mica or other suitable
material being inserted between the two for insulating purposes. The upper
end of the solenoid is held in position and insulated by means of a circular disc s,
of porcelain or other insulating material, fitting within the upper rim or ring n;
and having on the underside a central cylindrical projection t, which fits in the
upper end of the hole through the solenoid.
The advantages of this form of holder or bucket are, reduced loss and
consequently reduced heating by eddy currents in the case of alternating currents,
cheapness of construction and increased radiating surface to cool the coil.
In the third place my invention refers to the means for guiding the carbon
holders, and this portion of my invention is illustrated in Figs. 7 and 11 in
which u indicates the ring to which the reflector plate is sometimes attached. This
ring is provided at one side with a lug or projection v, in which is a hole, through
which latter the long vertical tube o passes. The outer side of this lug v is slit
through radially, and provided with a tightening up screw a, by means of which
the tube w can be tightly and securely clamped. The lower end of this tube is
bent inwards, so as to form a very stiff spring; and to which the lower end of the
guide wire is attached, the wire y passing through a hole in the end of the bent
portion, and being provided with a nut; by means of which the tension on the wire
is obtained. The upper end of the guide wire y is secured in the circular plate <,
from which the ring is suspended. The bent form of the lower end of the
tube w constitutes a spring of sufficient stiffness and range to keep the guiding
wire tight, notwithstanding the variations in length due to expansion when the
lamp is at work.
In the fourth place my invention refers to an improvement in the detail of
attaching the carbon holder to the sliding bracket which carries it. This is
illustrated in Figs. 8 and 9, which are respectively vertical and horizontal sections.
The carbon tube or socket 1 is attached to a screw 2, by means of a pin 3 passing
through the screw and sides of the tube. The screw 2 passes through a hole or
slot 4 in the horizontal arm of the sliding bracket 5, and is provided at the end
with a nut 6, by means of which it can be securely clamped to the horizontal arm;
insulating washers being inserted on both sides of the arm if required. The socket
or tube 1 is slitted at half its height about half way through, and a clamping
girdle 7 of the same depth as the slit, provided with a tightening screw, serves to
clamp the carbon in the tube or socket. y and wo indicate respectively the before
mentioned guide wire and tension tube. The socket or tube 1 may be circular,
oval, square, or of other desired section. The advantages of this connection are
simplicity, reduced cost and lightness.
Lastly my invertion comprises a new method of governing in the case of two
lamps running in series. This is diagramatically illustrated in Fig. 10, and
consists in controlling the governing device of the one lamp A by the main current,
and that of the other lamp B by a shunt across it.

page_text: Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is :-
1. A governing device for arc lamps consisting of a chain or cord pulley and a.
ratchet or grip wheel connected together, the latter operated by a pawl carried by
a pivotted or hinged lever, the axle or fulcrum of which is situated diametrically
or approximately diametrically opposite the arc of contact of the pawl and ratchet
wheel, the said lever being operated by the core of a solenoid or other electrical
governing device.
2. A governing device for arc lamps consisting of a chain or cord pulley and a
ratchet or grip wheel, the latter operated by a pawl carried at the end of a vertical
branch of a two armed horizontal lever, the axle of the said lever being carried
vertically above the axle of said pulley and wheel, the are of contact of said pawl
and ratchet wheel being about vertically beneath the axle of said ratchet wheel,.
one end of said lever being connected to the core of a solenoid or other electrical
governing device substantially as herein set forth and illustrated in Figs. 1 to 3.
3. A governing device for arc lamps consisting of a chain or cord pulley and
ratchet or grip wheel, the latter operated by a pawl carried on one arm of a two-
armed horizontal lever, the axle of said lever passing through the end of a vertical
branch of the opposite arm of said lever and about diametrically opposite the are
of contact of said pawl and ratchet wheel, one arm of said lever being connected
to the core of a solenoid or other electrical governing device, substantially as
herein set forth and illustrated in Fig. 3.
4. The construction of skeleton holder or bucket for the solenoids of arc lamps
consisting of a top ring and outside flange and bottom ring and inside flange, the
rings being connected by bars substantially as herein set forth and illustrated.
5. In combination with the subject matter of Claim 4, the employment of a disc
of insulating material having a cylindrical projection substantially as and for the-
purpose herein set forth and illustrated.
6. The device of a bent tube in combination with a wire guide for the carbon.
holder carriers of arc lamps, substantially as and for the purpose herein set forth
and illustrated.
7. In arc lamps the device for attaching the carbon holders to the sliding
carriers, consisting of the screw 4 provided at one end with a nut and baving a
pin 3 passing through it near the other end and also through the sides of the tube
or socket 1, substantially as herein set forth and illustrated in Figs. 8 and 9.
8. The method of running two lamps in series characterized by the governing
device of the one lamp being controlled by the main current and that of the other
lamp by a shunt current across it.
Dated this 16th day of October 1896.
J. CLARK JEFFERSON,
30 Park Row, Leeds, Agent for Applicant..