IMPROVEMENTS IN INCANDESCENT ELECTRIC LAMPS
Year: 1883

page_text: LETTERS PATENT to Richard Harrison of Union Chambers Grainger Street
West Newcastle-on-Tyne in the County of Northumberland for an Invention
of "IMPROVEMENTS IN INCANDESCENT ELECTRIC LAMPS
"
PROVISIONAL SPECIFICATION left by the said Richard Harrison at the
Office of the Commissioners of Patents on the 22nd June 1883.
RICHARD HARRISON of Union Chambers, Grainger Street West Newcastle-on-
Tyne in the County of Northumberland "IMPROVEMENTS IN INCANDESCENT
ELECTRIC LAMPS"
My Invention relates to the construction of the bulbs of incandescent electric
lamps and to the preparation and means of fixing the filament and its conducting
wires. In blowing the bulb, I form its neck of a flat approximately elliptical
Bection with a slit which opens the top of the neck and extends some way down
each of its narrow sidea. I attach the two ends of the carbon filament by iron
wires to the longer ends of two L shaped pieces of metal, and on the parts of
these pieces next their angles, I fix a coating of glass by squeezing on them
pieces of heated glass. I then insert the carbon into the bulb passing the tails of
the L pieces down the two slits of the neck, so that their ends project outwardly.
I then heat the neck of the bulb and, by means of a suitable pinching tool, I close
it in on the pieces, and at the same time on a mandril held in the centre of the
neck. I then draw out a tubular end to the bulb which serves for the exhaustion
of the bulb afterwards.
For preparing the filament, I cut a narrow strip of wood pulp paper, and having
bent it, I secure each of its ends to one end of a staple made of iron wire by
introducing the end of the filament and the end of the staple side by side into a
socket made of paper along with a suitable cement. The filament is then
carbonised in the usual way and, the bow of the iron staple being cut off, the ends
of the iron wire are secured to the L pieces of metal above mentioned.
For the purpose of condensing the filaments, they may be carbonised under
pressure in a liquid,

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Richard Harrison in the Great Seal Patent Office on the 22nd December
1883.
RICHARD HARRISON of Union Chambers Grainger Street West Newcastle-on-
Tyne in the County of Northumberland. "IMPROVEMENTS IN INCANDESCENT
ELECTRIC LAMPS"
For
My invention relates to the construction of the bulbs of incandescent electric
lamps and to the preparation and means of fixing the filaments and their
conducting wires. The bulb is blown, as shown in side and end views at Figs. 1
and 2 and in plan at Fig. 3 with a neck a of flat approximately elliptical section
The
having a slit b extending some distance down each of its narrow sides.
carbon filament, prepared and attached as I will hereafter describe, to two L shaped
pieces c c is inserted into the bulb, the pieces co taking the position shewn in
Fig. 4 their hook ends resting on the bottoms of the slits b. Before insertion, the
metal about the angles of the hooks is coated with glass. When they have been
inserted, the neck of the bulb is heated and is pinched in to the shape shewn in
plan at Fig. 5 and in section at Fig: 6; by heated nippers having jaws such as are
shewn in Figs. 8 and 9, while a tubular mandril f, which may be attached to the
nippers, is held in the neck of the bulb. By the action of the nippers, the neck is
squeezed in upon the pieces co hermetically sealing them in position, and during
this squeezing the tubular mandril f is connected by a flexible tube with.a supply
of air under a little pressure, which acting in the interior of the bulb keeps its
heated portions from collapsing. After the pieces co have been sealed in, the
upper tubular part of the neck above them is drawn out so as to form a small tube
as shown in Fig. 7, this tube serving afterwards as a connection to the apparatus
for exhausting the bulb, and being hermetically sealed after exhaustion.
preparing the carbon filament, I use a narrow strip of wood pulp paper and having
bent it, as shewn by h in Fig. 10, I secure its two ends to a staple k made of
iron wire, this being either a plain staple as shown in the upper part of Fig. 10,
or made with a coil in each of its limbs as shewn at o in the lower part of Fig. 10.
The ends of the filament are secured to the limbs of the staple by short pieces of
paper tube m m fixed with ordinary hard carbonaceous cement preferably
The paper
containing a metallic oxide which is reduced during carbonisation.
used for the tubes m m may be treated in the first place with sulphuric acid, or
the tubes may be moulded from pulp. The filament attached to the iron staple,
by which it is secured against distortion, is carbonised in the usual way by heating
in a closed vessel supplied with hydrocarbon or other suitable gas or vapour that
prevents oxidation. Instead of a gas or vapour, a liquid such as vaseline or
mercury may be employed to protect the carbon from oxidation, and this liquid
may be kept under pressure so as to condense the filament. After carbonisation
of the filament, the bow of the iron staple is cut off leaving only its two limbs
attached to the filament. These are secured to the ends of the L shaped pieces o c;
according to one method shown in Fig. 11, when the iron limb is made with a
coil o, the end of the piece o is inserted into the coil which is pinched upon it, and
sound contact can be secured by brazing. Or, as shewn in Fig. 12, the end of the
piece c may be widened out and have slits p cut in it through which the end of
is inserted. In Figs. 11 and 12 n indicates the coating of glass which is put on
the pieces o by squeezing it on in a heated state. The electric conductors for the
lamp are connected in any convenient way to the ends r r of the pieces that
project from the neck of the bulb.

page_text: Having thus described the nature of my invention and in what manner the
same is to be performed, I claim in respect of incandescent electric lamps.
First. The herein described method of forming the neck of the bulb and sealing
into it metallic pieces of ✓ shape having limbs within the bulb connected
to the carbon filament and limbs projecting through the glass to connect to
external conductors, substantially as herein described with reference to the
accompanying drawings.
Second. Carbonising the filament while it is united to an iron staple in a closed
vessel containing fluid preventive of oxidation.
In Witness whereof I the said Richard Harrison, have hereunto set my hand
and seal this twenty second day of December in the year of our Lord One thousand
eight hundred and eighty three.
R HARRISON. (L.S.)