Year: 1899

page_text: Date of Application, 25th Feb., 1899-Accepted, 15th Apr., 1899
We, WALTER CLAUDE JOHNSON, of The Dignaries, Westcombe Park, Blackheath,
in the County of Kent, Electrical Engineer, and ADOLPH WUNDERLICH, of No. 11.
Osborne Terrace, Westcombe Park, Blackheath, in the County of Kent, 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 follow-
ing statement:-
This invention relates to an improved construction of arc lamp of the kind
wherein the carbons are enclosed in a more or less hermetically closed globe or
glass. According to our improved construction the lamp contains the following
new features.
The upper carbon works entirely free and without holder in a cylindrical core
or armature of the regulating solenoid, the feed of the carbon being regulated by
a clutch device carried by the lower end of the armature, and consisting of a
number of pivoted levers or cam pieces so formed and acted upon by pins on the
solenoid armature that when the armature is in the lowered position the cams
are caused by gravity to move away from the upper carbon which can thus
descend freely. When the armature is raised, the said pins act upon the cams
so as to press these against the carbon, which is thus raised by the armature.
The current is conveyed to the upper carbon by contact pieces pivoted to a plate
which also forms the top enclosure of the lamp glass and these contact pieces
are also aranged to effect the automatic cut out, by forming on the upper part of
the upper carbon a circular groove with which the said contact pieces engage like
pawls when the carbon has descended to such an extent as to bring the groove
on a level with the contact pieces.
We will proceed to describe the above as also various other novel features
with reference to the accompanying drawings, in which Fig. 1 shews a vertical
section of the improved lamp while Figs. 2 to 5 shew enlarged sections taken
respectively at A A, B B, C C, and D, D, Fig. 1.
The regulating mechanism is contained in a casing a formed of a single cast-
ing, in the looped part 6 of which is situated the solenoid c. Within the central
tube a of the solenoid is the tubular core or armature e also formed as a single
casting, the lower flanged end of which has brackets f that carry pins g, which
operate upon the device h for clutching the upper carbon i. This clutch device
consists of a series of cam shaped levers h, that are pivoted to brackets on a loose
annular plate j. When the armature e is in the lowered position the plate j rests
upon the bottom of the cup shaped piece k that is secured to the lower end of
the casting ; in this position the action of gravity upon the upper ends of
the clutch levers h causes these to turn outwards upon their pivots so that they
release the upper carbon, which is then free to descend towards the lower carbon.
On the other hand when the lamp is put in circuit the armature e being drawn
upward, first acts upon the levers h by the pins 9 so as to cause these to clutch
:
:

page_text: the carbon, and then raises them together with the carbon so as to strike the arc.
As the carbons consume (which takes place at an exceedingly slow rate, owing
to their being enclosed practically airtight) the armature descends again causing
the levers to release the carbons sufficiently to effect the required downward
feed for maintaining the arc.
To the underside of the casting is secured in an insulated manner a cylindrical
piece into the lower end of which is screwed' the upper end of the frame m that
holds the glass n enclosing the carbons. Into the central opening of such frame
is screwed a disc which is secured in an insulated manner to a central brass
casting o having a disc p, at its lower end which constitutes the cap for closing
and holding the glass n, the lower end of which rests upon a disc q forming the
bottom of the frame m... The casting o is formed with a central cylindrical piece
having four vertical slotted wings in the slots u of which are situated contact
pieces pivoted at s to the wings and formed as shewn at Fig. 1 so that they
tend to fall inwards and thus make the necessary electrical contact with the
upper carbon for conveying the current thereto. The upper carbon has a circular
groove t formed near its upper end, and when it has burnt away to such an extent
that this groove arrives on a level with the upper ends of the contact pieces r,
these become engaged with such groove and in this préventing the farther descent
of the carbon, operate as an automatic cut out.
On the outer surface of the cylindrical-piece are formed ribs v carrying
notched insulating pieces w in the notches of which is wound the resistance coil
of the circuit, which coil is made in the form of a thin metal band, as shown,
owing to the coil being made of this form and-so-supported-that-almost the entire
surface thereof is in contact with the air, the heat generated will be most efficiently
conducted away therefrom. By this arrangement of the resistance coil a great
economy in space is obtained. For carrying the outer globe (or reflector as
shewn in dotted lines, or screen) there is secured between the casting a and
cylinder a thin metal cap a having a rounded coarse screw thread formed there-
on as shown, and a corresponding screw thread is formed on the neck of the globe
or reflector thus providing a ready means of attachment without requiring the
usual metal fittings on the globe. &c.
'
The magnetic circuit of the solenoid is closed at top by, the soft iron piece y
in a known manner which piece is extended conically downwards so as to act
upon the upper end of the armature e."
It will be seen from the above description that the improved lamp is of the
most simple construction and action the number of parts being reduced to a
minimum, and thereby decreasing both the size and expense of the lamp.
Having now particularly described and ascertained the nature of this invention
and in what manner the same is to be performed we declare that what we claim is:―
1. In an arc lamp, a cylindrical solenoid armature such as e, carrying pins g
at its lower end operating in combination with clutch levers or cams h in such
manner that on the rising of the solenoid armature the pins thereof in bearing
upon inclines on the levers cause these to clutch the upper carbon, while on the
descent of the armature the levers release the carbon substantially as described.
2. In an are lamp the employment of pivoted contact pieces such as r which con-
vey the current to the upper carbon and which also serve as automatic cut out by
engaging with a circular groove on the upper part of the carbon when this has
burnt away to a certain extent and thus prevent its further descent, substantially
as described.
3. In an arc lamp with enclosed carbons the combination of a tubular solenoid
armature e having pins at its lower end, a disc j carrying clutching cams or
levers operated by the pins of the armature, a casting of conducting material o
connected in an insulated manner to the upper end of the frame m, carrying
the lamp glass or globe enclosing the carbons, the casting being provided with
slotted wings within which are pivoted contact pieces r making contact with the

page_text: upper carbon, and also with a disc 2 which effects the closure of the top of the
lamp glass substantially as and for the purposes described.
4. In an arc lamp, the combination of a casing a for the upper part of the
lamp formed as a single casting with a slotted opening in which is situated the
regulating solenoid, a cylindrical piece secured in an insulated manner to the
casing, a lower carbon supporter m also serving as the glass holder secured to
the cylindrical piece 7 and connected in an insulated manner to a casting o
carrying the contact pieces and the disc closing the top of the glass n, arranged
and operating substantially as described.
5. In combination with an are lamp such as is referred to in the preceding
claim, a thin metal cap having a screw thread formed thereon into which is
screwed the outer globe, reflector or screen, of the lamp, substantially as described.
6. In an electric arc lamp, constructing the resistance coil of the circuit of
a thin band of metal wound round a number of radially arranged insulating
bars, so that the greater part of the coil is in free contact with the atmosphere,
substantially as and for the purposes described.
7. The herein described combination of parts constituting an arc lamp with
carbons enclosed under practical exclusion of the atmosphere, the said parts being
arranged and operating as herein described with reference to the drawings.
Dated this 25th day of February 1899.
ABEL & IMRAY,
Agents for the Applicants.