Method of Manufacturing Incandescent Electric Lamps.
Year: 1898

page_text: Date of Application, 16th Aug., 1898--Accepted, 5th Nov., 1898
COMPLETE SPECIFICATION,
Method of Manufacturing Incandescent Electric Lamps.
I, CHARLES ARTHUR ALLISON, of 52, Chancery Lane, London, in the County of
Middlesex, Patent Agent, do hereby declare the nature of this invention (which
has been communicated to me from abroad by John Thomas Lister, of the City
of Cleveland, State of Ohio, United States of America, Electrician, and William
Selah Chamberlain, of Cleveland, State of Ohio, United States of America,
Gentleman), and in what manner the same is to be performed, to be particularly
described and ascertained in and by the following statement: -
The objects of my invention are to provide a method of sealing the bulb from
the stem end, by means of which the various parts are more quickly and easily
grouped together; a more secure joint is obtained for the terminal metals and the
construction is altogether simplified.
My invention consists in the forms and manner of construction as exemplified in
the accompanying drawings, hereinafter described and specifically pointed out in
the claims.
In the accompanying drawings Fig. 1 is a central, longitudinal section of
completed bulb and stem; Fig. 2 is a transverse section on line X-X, Fig. 1;
Figures 3 and 4 show the separated details of stem ready to be placed in position:
Fig. 5 is a sectional detail enlarged to show connection of copper and platinum
wires; Fig. 6 shows a modified form.
In these views 1 is the bulb, shown as cylindrical and provided with smooth,
hemispherical extremities at 2 and 3, to insure clearness of the glass and perfect
radiation of light.
At the stem extremity is provided the cylindrical neck 4.
The manner of constructing the seal is as follows:-
--
Two tubes, one smaller than the other, as 5 and 6 are provided for insertion
within the neck, the larger tube being flanged at the outer extremity at 7, and
the smaller tube at the inner extremity at S.
The lower edge of the larger tube is then heated to softness and with a suitable
tool is drawn out into folded receivers for the filament terminals as shown at 9,
or in as many places as there may be terminals employed for the lamp. While
these folds are still soft the united extremities of the copper and platinum wires 10
and 11, forming the terminals, are inserted therein, as shown in Fig. 5. The
terminals are inserted at the point of union of the metals and the folds of soft
glass are then compressed about them with a suitable tool, thus entirely enclosing
them in the glass and preventing any danger of subsequent separation of the
two metals.
It will be seen that the folds 9 are drawn outwardly from the edge of the tube
and in this manner the enclosed terminals are further separated from one another
within the bulb, thus preventing danger of short circuiting of the current in ⠀

page_text: lamps of high voltage, which would occur if this precaution were not taken. Folds
of less size can be formed by slightly denting the edge of the tube, sufficiently to
receive the terminals.
The next step in the process is the insertion of the smaller tube within the larger,
and the lower extremities of each being heated to a welding heat, the outer edge
of the flange of the smaller tube is hermetically sealed to the inner lower edge of
the outer tube, each tube preserving its cylindrical form throughout.
The stem being formed in this manner and provided with the terminals em-
bedded in the folds or terminal receivers of the outer tube is now ready for attach-
ment to the open neck of the bulb as soon as the filaments are secured to the
terminals.
The flange upon the larger tube and the bulb neck are then heated to welding
heat and are fused together hermetically, thus completing the lamp ready for
exhaustion.
The last step of the process is then to exhaust the air through the inner tube
and to seal the projecting extremity thereof.
..
The advantages of this method of sealing the bulb are seen in 'the facility
with which all parts in turn are united and in the slight initial cost of the work.
When more than one filament is employed the corresponding poles" of the fila-
ments are united either inside or outside the lamp, for use in high voltage lamps,
as shown in Figures 3 and 6, thus forming an additional step in the process.
Having now particularly described and ascertained the nature of my said
invention, and in what manner the same is to be performed, I declare that what
I claim is:
1. The method of making incandescent lamps, herein described consisting in,
softening the inner edge of an outer tube, drawing the edge into folds, placing
the terminal wires therein and sealing them there, placing a flanged inner tube
within the outer tube and sealing the edge of the flange to the edge of the outer
tube, then sealing the outer tube to the open neck of the bulb, exhausting the air
from the bulb through. the inner tube, and finally sealing the open extremity of
the inner tube, as described.
2. The method of making an incandescent lamp, as described, consisting in,
making a flange on each of two tubes, one being larger than the other, heating
the unflanged edge of the larger tube till soft, and drawing the edge into outwardly
extending folds, placing the lamp terminals in the folds and sealing
them there, placing the smaller tube within the larger and sealing the edge
of the flange of the smaller tube to the inner free edge of the outer tube without
altering the shape of the tubes, attaching the filaments to the terminals, sealing
the edge of the flange of the outer tube to the edge of the neck of the bulb, and
finally exhausting the air through the smaller tube and sealing the same, as
described.
3. The method of making an incandescent lamp, as described, consisting in,
flanging two tubes at one end only, one tube being larger than the other, softening
the free edge of the larger tube and drawing out the edge at predetermined
points to form outwardly extending folds, inserting in said folds the
combined copper and platinum terminals, at their points of junction,
and sealing them there, placing the inner tube within the outer,
sealing the edge of the flange of the inner tube to the inner edge of the outer tube,
sealing the edge of the flange of the outer tube to the edge of the neck of the
bulb, exhausting the air from the bulb through the inner tube, and finally sealing
the inner tube, as described.
4. The method of making an incandescent lamp, as described, consisting in,
flanging two tubes at one end only, one tube being larger than the other, softening
the free edge of the larger tube and drawing out the edge at predetermined points
to form outwardly extending folds, inserting in said 'folds the combined copper and
platinum terminals, at their points of junction, and sealing them there, uniting
the corresponding poles of the filaments, placing the inner tube within the outer,

page_text: sealing the edge of the flange of the inner tube to the inner edge of the outer tube,
sealing the edge of the flange of the outer tube to the edge of the neck of the
bulb, exhausting the air from the bulb through the inner tube, and finally scaling
the inner tube, as described.
Dated this 19th doe A
1000