Improvements in Electric Arc Lamps.
Year: 1897

page_text: Improvements in Electric Arc Lamps.
We, WILLIAM JAMES DAVY and GEORGE THOMAS-DAVIES, Engineers, both of
27, Drayton Park, Holloway, in the County of London, do hereby declare the nature
of this invention to be as follows:-
This invention for improvements in electric arc lamps has for its object to enclose
the carbons, regulating mechanism and solenoid cores in an air tight chamber
provided with the necessary extensions, so as to obtain a simple and efficient lamp
that shall burn for a much longer period than an ordinary are lamp.
In an arc lamp constructed according to this invention the frame of the lamp
consists of the crown plate, an upper diaphragm, a lower diaphragm forming the top
of the chamber containing the mechanism and of two or more frame rods holding the
crown plate and diaphragms in their proper position. A bottom diaphragm forming
the support for the bottom of the chamber containing the regulating mechanism is
secured by side rods passing through the upper and lower diaphragms. A yoke
supporting the lower carbon holder which is fixed is carried from the bottom diaphragın
by yoke rods.
A casing closes the space between the lower and bottom diaphragm
and thus forms a closed chamber for the regulating mechanism.
The arc is enclosed in a glass bell fixed at its lower end by means of packing and
washer and nut to the lower carbon holder that passes through its end and has a tail
taking into and resting on a helical spring supported by a hollow screw plug fitting
in the yoke. By screwing up the plug the upper end of the bell is forced against an
asbestos ring in a recess in the bottom diaphragm, the spring allowing for expansion
and contraction. The central boss of the yoke is slotted its entire length to facilitate
the insertion of the upper carbon which is inserted sideways and then pushed into
position.
Each carbon holder is bored out to fit the carbons and the end is then split and
forced together by a circular spring in a groove round the holder.
The upper carbon passes freely through a central boss in the bottom diaphragm.
The upper diaphragm has on its under side an insulated diaphragm and the lower
and bottom diaphragms have on their upper side insulated diaphragms, the insulated
diaphragms being all secured by insulated screws. A central tube and two side tubes
are fitted into the two upper and lower insulated diaphragms and extend upwards
beyond the upper diaphragm and are capped. The lower ends open out into the
chamber containing the regulating mechanism. The two side tubes serve to receive
the cores of the solenoids and one may form also a dash pot. The centre tube serves
to receive the upper carbon and its parts and may have a safety valve on its cap. The
upper carbon holder slides in the central tube between two rings and is connected by
a helical conductor in the upper part of the central tube to the central tube and thence
through one of the side rods to one terminal. The carbon passes through a grip
device situated in the chamber between the lower and bottom insulated diaphragms
77.

page_text: and acting on the upper carbon to strike the arc and feed it. A suitable grip device
is described in a prior application No. 3330/1897.
The spaces open to the arc are thus the glass bell, the chamber containing the
mechanism and the three tubes and these spaces are made as small as possible.
To renew the carbons, the glass bell is removed, then the lower carbon, afterwards
the upper carbon is drawn out and replaced by pushing up a fresh one, and finally the
old upper carbon is inserted in the lower carbon holder.
The lower carbon holder is connected to one end of the series coil connected at its
other end to the other terminal. In the case of shunt controlled lamps, the lower
carbon holder is connected direct to the terininal.
Dated this 25th day of February 1907
WHEATLEY & MACKENZIE,
40, Chancery Lane, London, W.C., Agents.
We, WILLIAM JAMES DAVY and GEORGE THOMAS DAVIES, Engineers, both of Horsell
Road Works, Highbury, N., in the County of London, late of 27, Drayton Park,
Holloway, London, 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 for improvements in electric are lamps has for its object to enclose
to an improved manner the carbons, regulating mechanism and solenoid cores in an
air tight chamber provided with the necessary extensions, so as to obtain a simple
and efficient lamp that shall burn for a much longer period than an ordinary arc lamp.
In the accompanying sheet of illustrative drawings:-Figs. 1 and 2 are sectional
elevations at right angles to one another of an enclosed arc lamp constructed according
to this invention. Fig. 3 is a plan of the top insulated diaphragm of the lamp.
Fig. 4 shows a half plan of the intermediate diaphragm and of the intermediate
insulated diaphragm. Fig. 5 shows a half plan of the bottom diaphragın and both
insulated diaphragms. Fig. 6 is a plan of the arc regulating mechanism. Fig. 7
shows a modification of the lower carbon holder. Fig. 8 is a plan of the bottom yoke.
The frame of the lainp consists of the crown plate a, an upper diaphragm b, an
intermediate diaphragm c forming the top of the chamber containing the mechanism
and of two or more frame rods d holding the crown plate a and diaphragms 6 c in their
proper position. On the underside of the upper and intermediate diaphragms are
insulated diaphragms 61 c¹, and a bottom diaphragm e forning the support for the
bottom of the chamber containing the regulating mechanism is secured by side rods f
passing through holes in the upper and intermediate diaphragms, and secured in the
insulated diaphragms b¹ c¹. Secured on the top of the bottom diaphragm e is a
bottom insulated diaphragm e¹. A yoke g supporting the lower. carbon holder h
which is fixed is carried from the bottom insulated diaphragm e¹ by yoke rods i. A
casing encloses the space between the intermediate insulated and bottom
diaphragms c' e and thus forms a closed chamber for the regulating mechanism.
The arc is enclosed in a glass bell m fixed at its lower end by means of packing and
washer and nut n to the lower carbon holder h that passes through its end and has a
tail h¹ taking into and resting on a helical spring o supported by a hollow screw plug o¹
fitting in the yoke g. By screwing up the plug o¹ the upper end of the bell is forced
against an asbestos ring e² in a recess in the bottom diaphragm e, the spring allowing

page_text: for expansion and contraction. The central boss of the yoke is slotted at g² its entire
length to facilitate the insertion of the upper carbon which is inserted sideways and
then pushed into position.
Each carbon holder hp is bored out to fit the carbons and the end is then split and
forced together by a circular spring r in a groove round the holder.
The upper carbon passes freely through a bush in a central boss in the bottom
diaphragm e.
The insulated diaphragms b¹ c¹ and the bottom diaphragm e are all secured to their
diaphragms by insulated screws. The screws of the bottom diaphragm also secure
the casing by means of the wing nuts e'. The edges of the casing being packed
with asbestos as shown. A central tube 8 and two side tubes t t¹ are fitted into the
upper and intermediate insulated diaphragms b' c¹ and extend upwards beyond the
upper diaphragms and are capped. The lower ends open out into the chamber
containing the regulating mechanism. The two side tubes t t¹ serve to receive the
cores t² 3 of the solenoids t t and one t¹ may form also a dash pot. The centre tube s
serves to receive the upper carbon and its parts and may have a safety valve on its
cap. The upper carbon holder p slides in the central tube between two stops p² p³
and is connected by a helical conductor p in the upper part of the central tube to
the central tube and thence through one of the side rods f to one terminal v.
The carbon passes through a grip device situated in the chamber between the
intermediate and bottom insulated diaphragm and acting on the upper carbon to
strike the arc and feed it.
The gravity friction grip device consists of two pairs of links 1, 2, pivoted together
at one end and carrying projections or jaws 3 between which passes the carbon.
The support links 1 are pivoted to the links 4 suspended from the intermediate
diaphragm c and have arms 5 fixed thereto. The L-lever 6 is pivoted at its angle
between the free ends of the arms 5 and one end is pivoted between the free links 2
and its other end is connected by an adjustable link 7 to a lever 8 pivoted on lugs 9
on the intermediate diaphragm cl and connected at its ends to the cores t2 3 of the
main and shunt solenoids 4 t5 respectively. Normally the lower ends of the link 1, 2,
rest on the bottom diaphragm e.
The operation is as follows:-The carbons are normally in contact and the grip
device rests on the bottom diaphragm e. On passing the current to the lamp, the
core 12 of the main solenoid #4 is drawn down and raises the end of the lever 8 causing
the jaws 3 to first grip the carbon and then to raise the links 1, 2, off the diaphragm
and raise the carbon to strike the arc. As the arc lengthens due to the burning
away of the carbons the power of the main solenoid t' decreases and that of the shunt
solenoid increases then gradually the grip device is lowered on to the diaphragm e and
the jaws relax their hold on the carbon and a continuous and steady feed is obtained
by the carbon feeding slowly through the jaws.
The spaces open to the arc are thus the glass bell, the chamber containing the
mechanism and the three tubes st t¹ and these spaces are made as small as possible.
To renew the carbons, the glass bell m is removed then the lower carbon holder is
unscrewed from the bell fitting, then the carbon remnant removed and afterwards the
upper carbon is drawn out of its holder p and replaced by pushing up a fresh one, and
finally the remnant of upper carbon is inserted in the lower carbon holder h.
The lower carbon holder h is connected to one end of the series coil connected at
its other end to the other terminal. In the case of shunt controlled lamps, the
lower carbon holder is connected direct to the terminal.
It will readily be seen that the main frame work of the lamp is insulated from the
external casing.
Having now particularly described and ascertained the nature of our said invention,
and in what manner the same is to be performed, we declare that what we claim is :-
1. The improved arrangement of enclosed arc lamp combined with the insulated
framework.

page_text: 2. The improved enclosed are lamp substantially as described with reference to the
drawings.
Dated this 25th day of November 1897.
WHEATLEY & MACKENZIE,
40, Chancery Lane, London, W.C., Agents.