Improvements in the Manufacture of Incandescent Electric Lamps.
Year: 1892

page_text: Date of Application, 22nd Mar.. 1892
Complete Specification Left, 22nd Dec., 1892-Accepted, 18th Mar., 1893
PROVISIONAL SPECIFICATION.
Improvements in the Manufacture of Incandescent Electric Lamps.
I, JAMES SWINBURNE, of Broom Hall Works, Teddington, Electrical Engineer
do hereby declare the nature of this invention to be as follows:-
My invention refers to improvements in the manufacture of incandescent electric
lamps.
Up to the present time platinum wire alone has been used for leading in wires
for lamps. This metal is expensive, and attempts have been made to substitute
cheap wires, but none have been commercially successful.
According to my invention, brass wire may be used.
Instead of brass, iron or nickel may be used with or without enamel, but coated
with tin or some equivalent metal. I find that ordinary tinned iron wire will seal
into glass. Iron is preferable. A thick wire may be used, so that strength is
obtained, and the wire is not so easily melted in the blow pipe flame. Nickel may
be employed instead.
For sealing cheap metals into lamps, I sometimes use a special enamel which
dissolves the oxide formed on the surface of the metals. Such an enamel may
for instance contain borax or similar compounds. In some cases I use a wire which
does not seal perfectly, and when cold, I apply a little silicate of soda, which runs
in and fills up the cracks and then hardens.
Instead of wires I sometimes employ suitable punchings with eyes, & carbon-
grips. For instance a piece of tinned iron may have a clamp at one end, a thin
middle portion for sealing into the glass, & a strong eye to come outside the lamp.
Or the clamp & eye may be of thick conductor, brass for example, while a thin
piece of copper is actually the seal.
Dated this 21st day of February 1892.
JAMES SWINBURNE.
COMPLETE SPECIFICATION.
Improvements in the Manufacture of Incandescent Electric Lamps.
I, JAMES SWINBURNE, of Broom Hall Works, Teddington, Electrical Engineer
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 refers to improvements in the manufacture of incandescent electric
lamps.
Up to the present time platinum wire has alone been used for sealing into glass
as leading wires for incandescent lamps.
This metal is expensive, & attempts have been made to substitute cheap wires,
but none have been commercially successful as far as I know.
I have found that several cheap wires can be employed. The wire I prefer is
tinned iron, though fair results may be obtained with equivalent wires, such as
tinned nickel. Apparently the glass dissolves the oxide of tin formed, & thus seals
well to the wire. Metals or alloys coated with lead, or solder may therefore, be
used without departing from my invention.
I may also use any suitable enamel which dissolves the particular oxide formed,
& which also joins well with glass. There are in fact, many methods which will
suggest themselves, & which may work; but I have not worked them out
[Pine Rd77

page_text: individually as that is not necessary, but I consider such methods, if based on the
same principles as my present invention, to be included in my claims.
Instead of using a wire, such as tinned iron, which seals into glass, I may employ
brass wire, or any wire which has the same property as brass, namely that of being
able to have glass fused around it without cracking it on cooling. Brass wire does
not appear to make an air tight joint with glass, though thick pieces can be sealed
in without cracking the glass. To make such joints tight I lute them with silicate
of soda or some such material. If silicate of soda is employed it is allowed to
harden, & is varnished outside, or left till the air has acted on it thoroughly.
Instead of wires I sometimes employ suitable punchings with eyes for holding
For instance, a piece of tinned
the lamp, & carbon-grips to clamp the filaments.
iron may have a clamp at one end, a thin middle portion for sealing into the glass,
& a strong eye to come outside the lamp. Or the conductors may be suitably
shaped pieces of brass, for example, sealed with sodium silicate or equivalent lute.
It is then apt to
Copper wire may be used, with arsenic enamel if it is thin.
melt in the blow pipe flame. A thin piece of copper may be used between two
thick pieces of non sealing metal, so that the thin copper is not exposed to the
blow pipe flame.
The iron should be freed from occluded gases as thoroughly as possible before
use. Heating under a suitable flux such as fused borax is a good method of
getting rid of the gases.
Having now particularly described & ascertained the nature of my said inven-
tion, & in what manner the same is to be performed, I declare that what I
claim is :
In an incandescent lamp-
:
1. Leading-in wires of a metal with a surface of a metal whose oxide is acted.
upon by the vitreous material, surrounding it.
2. Leading-in wires or conductors of iron or its equivalent coated with tin or its
equivalent.
3. Leading-in conductors sealed by means of silicate of soda or an equivalent lute
substantially as described.
4. Leading-in conductors consisting of strongly made metal pieces, with eyes &
carbon clamps substantially as described.
5. Leading-in conductors with a central or intermediate piece of thin copper
substantially as described.
6. Leading-in conductors of such a material as brass embedded in the glass, so
as to be held by it, with a short intermediate piece of platinum; tinned iron; or
other sealing wire to render the leading in air tight.
7. Leading-in conductors of the kind described freed from occluded gases as
described.
8. The improvements in manufacture substantially as described.