Improvements in Incandescent Electric Lamps.
Year: 1894

page_text: Date of Application, 16th Feb., 1894-Accepted, 17th Mar., 1894
COMPLETE SPECIFICATION.
Improvements in Incandescent Electric Lamps.
I, JOSEPH WALTER TURNBULL, a citizen of the United States, residing at
Pascagoula, County of Jackson, and State of Mississippi, United States of
America, Mechanic, 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 :-
The object of my invention is to produce an improved incandescent electric lamp
in which a central tube or enclosed passage is employed as a means of ventilation
for keeping the lamp cool and as a reflector introduced within the filaments, and in
which the central tube is made a separable part to provide for the renewal, and at
a comparatively small cost, of the filaments when they shall have burned out.
By the use of the central tube also a new and preferred form of wiring may
be employed, wires connected immediately with the filaments being used within
the tube.
In the accompanying drawings:
Fig. 1 is a central vertical section of my lamp, showing the parts assembled and
illustrating one method of wiring;
Fig. 2 is a similar view, showing another method of wiring;
Fig. 3 illustrates a group of the several parts separated.
Referring to the figures on the drawings:
1 indicates a transparent bulb or body part, which may be made of any suitable
construction, shape and dimensions.
2 indicates a neck preferably projecting outwardly and 3 a collar of smaller
dimensions than the neck and preferably projecting inwardly. The neck and the
collar are designed to receive a tube 4, fitted at one end to the collar 3 and having
an enlarged head 5 fitted to the inside of the neck 2. The tube is made of glass
and is, in practice, accurately fitted to the neck and collar by suitable means, as for
instance, grinding. In uniting the bulb to the tube, the former is first expanded
by a moderate heat and the tube is slipped into place. When the bulb cools a
perfect joint will be formed between the outside of the tube and the inside of the
neck and collar, respectively. The parts being so united a vacuum may be created
within the bulb by tapping it in the usual manner.
If it is preferred to unite the tube and bulb without heating, a wax joint or seal 6
may be employed between the ends of the tube and the neck and collar respectively,
the object in this connection being to produce a vacuum chamber between the walls
of the tube and the walls of the bulb.
.7 indicates a wire supporting connection or reflector tube preferably made of a
metal cylinder having an outer silvered or burnished coating and adapted to fit
within the tube 4 and to form within the same a reflector. It is provided with a
socket head 8 to which the line connections may be made. It is also provided with
suitable means for retaining it in position, as for instance, spring clips 10 adapted
to engage with an annular rim 11 of the head 5.
12 indicates a carbon or filament. It is connected to electric wires 13 and 14
adapted to convey an electric current. These wires are preferably united to
connecting pieces 15 preferably made of platinum and embedded in the glass walls
of the tube 4. They are also preferably located near the top and bottom of this
tube, respectively. The filament may be coiled around the tube, as shown in Fig. 1,
having connecting pieces 15 at its lower and upper ends united to the wires 13
and 14; or separate filaments upon opposite sides of the tube may be employed,

page_text: having both their upper ends connected to the wire 13, for example, and both
their lower ends connected to the wire 14, as shown, for instance, in Fig. 2 of the
drawings.
In assembling the parts, as above explained, the bulb and tube having been
properly fitted, the former is expanded by heat and the latter slipped into place,
the filaments having been adjusted before the tube is inserted. Afterward, by
tapping the bulb the air may be exhausted from it in the usual manner.
After the lamp is otherwise completed the stopper may be inserted in place and
the wires 13 and 14 connected to it, as through insulated screws or contact pieces 16
and 17. In this manner I provide for the perfect ventilation of the lamp, the
renewal of the fibre when it is burned out, and means for fastening it to a socket
without the use of plaster or any similar permanent joints.
I do not confine myself to the details of construction herein shown and
described, but reserve the right to modify and vary them at will within the scope
of my invention.
Having now particularly described and ascertained the nature of my said inven-
tion, and in what mauner the same is to be performed, I declare that what I
claim is
1. The combination with a bulb, of a separable tube, open at both ends, inserted
therein and forming therewith a vacuum chamber, substantially as specified.
2. The combination with a bulb, of a separable tube therein, open at both ends,
extending entirely through the bulb, and supporting filaments forming thereby
a ventilated bulb, and readily removable filament support therein, substantially as
specified.
3. The combination with a bulb and tube open at both ends, of a separable open
ended reflector therein, substantially as specified.
4. The combination with a bulb and a separable hollow open ended tube
extending entirely therethrough, and supporting filaments, of a likewise hollow and
open ended burnished tube therein adapted to constitute a ventilated reflector,
substantially as specified.
5. The combination with a bulb and tube therein open at both ends, of a
separable wire supporting tube in said first named tube, substantially as specified.
6. The combination with a bulb and separable tube, open at both ends, extending
entirely therethrough, of another likewise open ended tube within the first nameil
tube adapted to constitute a ventilated reflector and to support connecting wires,
substantially as specified.
7. The combination with a bulb and an open ended separable tube, extending
therethrough, and supporting filaments, of a wire supporting burnished tube therein,
and wires supported thereby, said tube constituting a ventilated reflector, and said
wires being adapted to connect the filaments with the circuit wires, substantially as
specified.
8. The combination with a bulb, of a separable tube therein, filaments secured
upon the exterior of the tube by connecting pieces, a separable wire supporting
connection tube upon the interior thereof, and connecting wires within said
connection tube adapted to connect said connecting pieces with the circuit wires,
substantially as specified.
9. The combination with a bulb provided with an everted neck, of a tube
extending therethrough having an enlarged upper end or head adapted to fit within
said neck, substantially as specified.
10. The combination with a bulb having an everted neck, of a tube therein
having an enlarged head adapted to fit within the neck, and a burnished reflector
tube within said first named tube and provided with an enlarged end or socket
head adapted to fit within the enlarged head thereof, substantially as specified.
11. The combination with a bulb having a neck and collar at opposite ends
thereof, respectively, of a tube adapted to be inserted into the same to form with

page_text: the walls of the neck and collar an air tight joint, substantially as and for the
purposes set forth.
12. The combination with a bulb provided with an everted neck, and an
inverted collar, of a separable tube therein supporting filaments, substantially as
specified.
13. The combination with a bulb provided with an everted neck and an inverted
collar, of a separable filament supporting tube therein, and a hollow reflector within
said tube, substantially as specified.
14. The combination with a bulb provided with an everted neck and an inverted
collar, of a separable filament supporting tube open at both ends extending entirely
therethrough, and a hollow open ended burnished tube supporting connecting wires,
said tube constituting a ventilated reflector, and said wires being adapted to connect
the filaments with the circuit wires, substantially as specified.
15. The combination with a bulb, of a tube extending therethrough, and another
tube inserted therein, said tubes being provided with co-operating mechanism
adapted to sustain their proper relations, substantially as specified.
16. The combination with a bulb and a tube extending therethrough, and a
superimposed tube thereupon, adapted to constitute the inner wall of a cylindrical
vacuum chamber within the bulb, of a plurality of filaments within the vacuum
chamber, wires within the inner tube, means for connecting the wires with the
opposite ends, respectively, of the filaments, and means for connecting each of said
wires with the circuit wires, substantially as specified.
Dated this 10th day of February 1894.
JENSEN & SON,
77, Chancery Lane, London, W.C., Patent Agents.