Improvements in Incandescent Electric Lamps.
Year: 1892

page_text: Date of Application, 18th Aug., 1892-Accepted, 17th Sept., 1892
COMI DULE
[Communicated from abroad by EUGENE MOUAT, of Boston, Massachusetts,
United States of America.]
Improvements in Incandescent Electric Lamps.
I, HENRY HARRIS LAKE, of the firm of Haseltine Lake & Co., Patent
Agents, 45 Southampton Buildings, in the County of Middlesex, 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:-
My invention relates to a method of arrangement and construction of the parts
of an incandescent electric lamp, that are more immediately connected with the
leading in wires, and the sealing-in and mounting of the same. The object being
to lessen the length of platinum wire required and to so improve the "mount
and its connection with the body of the bulb of the lamp that there shall be the
least possible danger of accidental fracture and leakage at the places of juncture
of the wire with the "mount" and of the "mount" with the body of the bulb.
My invention is illustrated in the accompanying drawings in which:-
Figure 1 is a vertical section of a completed electric lamp embodying my
invention.
Figure 2 is a vertical section of a "mount" before it is sealed in to the bulb.
Figures 3 to 10, inclusive, show the various steps in the making of a lamp,
which are taken in the practice of my invention.
In manufacturing lamps in which my invention is involved, the procedure is as
follows:
For each lamp leading in wires are prepared by uniting lengths of previously
formed platinum wire to suitable lengths of copper wire by fusing.
A glass tube of suitable size and of a length convenient for handling is heated
at one end, and the leading-in wires placed within it so as to occupy diametrically
opposite positions in relation to each other in the tube (see Figures 8 and 8*) so
that the platinum parts will come in contact with the inner edge of the glass and
adhere to it, the temperature of the glass being sufficiently high to admit of this
adhesion. Now the wire end of the tube is heated to such a degree that it will
collapse into a globular shape and form an air-tight seal about the wires (see
Figures 9 and 9). The wires are now drawn farther away from each other and
"thus formed appears as
outwardly, the glass still being hot so that the " mount
shown in Figures 10 and 10ª. This drawing of the wires, as described, increases
the length of contact, and insures better adhesion of the glass and platinum,
thereby preventing leakage. It also reduces the glass to a thickness and form
admirably adapted to resist cracking, the drawing action leaving the glass without
internal strain.
66
"
"
A "mount as represented in Figure 2, consisting of a glass tube carrying
leading-in" wires to which a "filament" is suitably attached and whose open end
is not expanded is prepared. A bulb is then taken (Figure 3) to which a small
tube has been attached as at a, but whose neck is as it comes from the glass
house, and the "mount (Figure 2) is placed loosely within it (the bulb being
held horizontally) as shown in Figure 4. This causes the filament to be deflected
against the bottom end of the bulb by the weight of the "mount," but well
prepared filaments will not be injured thereby, but will slip around the bulb as
it is slowly turned in the blowers flame. The neck of the bulb is now heated at
the line y y (Figure 4) and the outer end drawn off, leaving the neck as shown in
Figure 5.
The slender glass spur resulting from the last operation is scratched with a file

page_text: "
"
"
and broken off at the line zz (Figure 5) leaving an opening at least as small as
the unexpanded open end of the " mount tube. Through the small opening thus
formed, the wires of the "mount are caused to protrude by simply inclining the
bulb, as shown in Figure 6, and are there held by pincers, so that the unexpanded
end of the "mount is brought in contact with the parts around the opening
which are now heated and blown, until a union takes place, resulting in the form
shown in Figure 7 The neck end of the bulb is again softened in the flame, and
the final step taken, which is to grasp the wires with pincers and push the "mount
and adjacent parts inward, properly locating the filament and giving the finished
form, that of an inwardly. projecting cone, as shown in Figure 1, in which the
line shows the juncture of the unexpanded "mount" tube to the substance of
the bulb.
"
"
This act of pushing in the "mount is important, as it has a tendency to reduce
the thickening of the glass at the line juncture, and gives the parts a form well
adapted to eliminate and resist strains in the glass.
Lamps made by this method very seldom crack and require no annealing, while
the operation is so simple that the necessary skill to perform it is more easily
acquired than in any other method known to me.
While I am aware that many ways of "sealing in" tubular " mounts "have
been used, they have always involved an expanded tube, which is productive of
much after damage, from cracking, and requires more labour in making.
"
By using an inexpanded tubular " mount I am able to accomplish several
useful results, most important of which are economy in labour and skill, and the
manufacture of a lamp that will not crack or leak in the neck.
My invention is especially useful in the making of incandescent lamps of large
size, since in such lamps there is particular need of keeping the lines of juncture
as short as possible.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed, as communicated to me
by my foreign correspondent, I declare that what I claim is :-
1. The above described method of making an incandescent electric lamp con-
sisting of the following steps:--1st uniting to the interior of an adhesively hot
glass tube, two platinum wires, 2nd, causing the said tube to collapse by heat, so
that the edges of the tube shall seam together and form a globular mass around
the wires; 3rd, drawing the wires away from each other and outwardly, dragging
the adhering glass with them so as to ensure better contact and to leave the glass
in better form for resisting fracture, substantially as described.
"3
2. In an incandescent electric lamp, the method of manufacture consisting of the
following steps:-1st, placing the prepared tubular "mount
" with attached
filament, loosely into the open neck lamp bulb; 2nd, drawing down the neck of the
bulb while the "mount is within it, and cutting off the former at a point where
it is at least as small as the end of the "mount tube; 3rd, melting together the
unexpanded open end of the "mount" tube, and the drawn-out neck of the lamp-
bulb; 4th, pushing the "mount" and adjacent parts inward, until the filament is
properly located, and the end of the neck of the bulb assumes the form of an
inwardly projecting cone, substantially as described.
ليود
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C., Agents for the Applicant.