Improvements in and relating to Electric Incandescent Lamps.
Year: 1893

page_text: Date of Application, 24th Mar., 1893-Accepted, 6th May, 1893
COMPLETE SPECIFICATION.
Improvements in and relating to Electric Incandescent Lamps.
I, THEODOR STOBER of No. 1 Gertrudenstrasse, Braunschweig, in the German
Empire, Manufacturer, 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 relates to electrical incandescent lamps and its object is to provide
means by which the broken or burnt filaments in such lamps may be replaced by
new ones.
This is accomplished by forming the base of the lamp with a removable plug
which carries the filament holders and is furnished with an air cock or valve.
Different ways by which this invention may be carried into effect are illustrated by
the accompanying drawings reference to which is hereinafter made.
Figure 1 illustrates a longitudinal section of a lamp furnished with a removable
plug and air valve;
Figure 2 is a similar view of a lamp having a modified form of plug and air
valve; and
Figure 3 illustrates a combination of the two forms previously shewn.
Referring to Figure 1 a brass ring B is cemented to the glass bulb by means of
the cement C. A joint ring D of asbestos or indiarubber is inserted between the
edge of the glass bulb A and a plug E of vulcanite or similar material which is
introduced into the straight brass ring B and fixed by means of small screws F.
A tap or valve body H with central through bore G is screwed into the closing
plug E. The valve H near the middle is fitted with the plug I by means of which
it is closed or opened. A cap K is fitted over the end of the valve H.
The outer screwed contact L' is secured in place by the insulating cement L.
The insulating plug E carries the filament holders one of which is connected to the
valve H and the other to the outer screw L. The cap K and the screw L' thus
form the contacts of the lamp. This method of forming the contacts is the same in
the other illustrated modifications.
The glass bulb A is pressed against the joint ring D by means of the outer air
and is furthermore beld by the screws F so that it cannot drop when the tap I is
opened. When the carbon thread is consumed or broken the cap K is screwed off,
the air-cock I is opened cautiously, and air allowed to enter into the glass bulb. The
screws F are then removed and the plug E together with the filament holders is
taken out of the brass ring B. A new filament is then fitted to the plug E and the
whole again introduced into the ring B and fixed by means of the screws F. The
lamp is then fixed to a suitable air pump by means of the screw L', the air pumped
out of the bulb, the cock I closed and the cap K screwed on again.
In the lamp illustrated by Figure 2, the straight ring B is replaced by a bent
screwed ring B, in other respects the glass bulb A is put on to the joint ring D as
before and cemented in by means of plaster of paris C.
The vulcanite plug E is screwed into the thread of the ring B and the brass
contact screw L' is screwed on to the plug E and filled with plaster of paris at
the top.
The lower part of the plug E carries a plate M with a conical valve seat in the
centre. A ferrule O with internal thread is fitted upon the plate M and contains
the valve screw R which can be screwed up and down with its valve cone P to close
or open the valve seating N. Above the valve-cone P the valve screw R is
provided with a cross bore S and rectangularly to this with a central bore G which
can be closed by the cap K serving as a protection for the thread and as one of the
contacts.

page_text: When the carbon thread is consumed the cap K is removed and the valve screw
screwed up slightly so that air can slowly enter into the glass bulb. The plug E is
then removed and the consumed carbon filament replaced by a new one.
The plug E
is then screwed back into the ring B the lamp is placed in connection with an air
pump, the air is pumped out and the cone P of the valve-screw R is again screwed
firmly down on to the valve seat N.
The form of lamp shewn in Figure 3 illustrates the combination of the plug
shewn in Figure 1 with the valve illustrated in Figure 2.
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―
In an electrical incandescent lamp the combination with the base of the lamp of
a removable plug carrying the filament holders and contacts and an air valve or
cock all constructed and arranged substantially as and for the purpose hereinbefore
set forth and as illustrated by the accompanying drawings.
Dated this 23rd day of March A.D. 1893
WILLIAM E. HEYS,
Agent for the Applicant.