Year: 1888

page_text: I, RANKIN KENNEDY, of the Electric Lamp Works, 115 Woodside Road, Glasgow,
Lanarkshire, Electrical Engineer, do hereby declare the nature of my said Invention
to be as follows:-
My Invention has reference to improvements in incandescent electric lamps, and
particularly suitable for the larger sizes of these lamps.
And the nature and novelty of my improvements consist in using two small rods,
preferably are carbons, as the incandescent conductor within the vacuum globe. The
lower ends of these rods or carbons would be joined at opposite sides to the conductors
or wires at the end of the lamp, preferably by cement, and the rods would be laid or
inclined at an angle and their other ends joined to each other, preferably by cement
at the apex. The rods or carbons would thus form an isoceles triangle, and act as a
continuous incandescent conductor for the electric current to pass to produce the
light, and form a very strong and durable electrode for incandescent lamps.
Dated this 21st day of February 1888.

page_text: COMPLETE SPECIFICATION.
Improvements in and relating to Incandescent Electric Lamps.
I, RANKIN KENNEDY, of the Electric Lamp Works, 115 Woodside Road, Glasgow,
Lanarkshire, Electrical Engineer, do hereby declare the nature of my said invention,
and in what manner the same is to be performed, to be particularly described and
ascertained in and by the following statement in writing, reference being had to the
accompanying Sheet of Drawings and to the letters and figures marked thereon, that
is to say: :-
My said invention has reference to improvements in incandescent electric lamps,
and particularly suitable for the larger size of these lamps.
The nature and novelty of my improvements consist in using two small rods,
preferably are carbons, as the incandescent conductor within the vacuum globe.
The lower ends of these rods or carbons would be joined at opposite sides to the
conductors or wires at the end of the lamp, preferably by deposited carbon cement,
and the rods would be laid or inclined at an angle and their other ends joined to
each other, preferably by deposited carbon cement at the apex. The rods or carbons
would thus form an isosceles triangle (without the base) and act as a continuous
incandescent conductor for the electric current to pass to produce the glow light, and
form a very strong and durable electrode for incandescent lamps.
And in order that my said invention and the manner of performing or carrying
the same into effect or practice, may be properly understood, I have hereunto
appended an explanatory Sheet of Drawings, in which Figure 1 is an elevation of an
incandescent electric lamp constructed in accordance with my invention, having fitted
therein my new arrangement of acute angled continuous incandescent carbon con-
ductor a, a, a³. While Figures 2 and 3 are an elevation and plan, respectively,
showing the arrangement of spring clamping device A, A¹, used in cementing the
carbon electrodes a, a', to each other at their apex or one end a*, and which is also
used to join or cement the other ends of these electrodes a a' at to the platinum
wires or conductors b¹, b¹.
Referring to these Drawings :-In carrying my invention into practice, I take two
straight rods a and a¹ of ordinary carbon of equal length and section, this length and
section being made proportionate to the quantity of light to be given by the
conductors or lamps. Thus for a 300 candle light worked at a 100 volts pressure,
the conductors a and a would each be made about four inches long and half a
millimetre in diameter. And for 1000 candle light worked at 50 volts pressure, the
length of each conductor a, a', would be about 9 inches, and the sectional diameter
about 1.25 millimetres. The rods or conductors a and a¹ are joined together at their
one ends to form the apex a* of an acute angle, by clamping each rod a and a¹,
separately, by the swivelling clamps A, A', the one spring clamp A being connected
by a wire c from the screw terminal C to the positive pole of a dynamo electric
machine, and the other clamp A', terminal C¹, and wire c' to the negative pole of the
dynamo, allowing about an eighth of an inch of each rod a a¹, to touch each other

page_text: and project under and beyond the points A³ of the swivelling spring clamps A, A',
the extreme ends of the rods a a¹ being in electric contact with one another at a²
above the slate or plate insulator A³. The clamps A, A', and points a² of the rods a, a',
in contact, are then immersed in a pure hydrocarbon liquid, such as Benzole, and
the electric current is turned on from the dynamo through the wires c, c', and
terminals C, C, to the spring clamps A, A', and the points a² of the rods a, a', in
contact become incandescent and decompose the hydrocarbon, the carbon being thus
deposited as a cement on the joint at the ends a' of the rods a a' and firmly binds
then together. The spring clamps A A' are then turned round on their fulcrum
at C, C, by the handles A¹ and the carbon electrodes a, a', removed with their
finished joint a. The rods or conductors a a¹ are joined or cemented at their lower
ends, either before or after being joined at their apex a³, but preferably before,-
to platinum conductors b', b, by carbon deposited cement in the same or in an
equivalent manner to that hereinbefore described for joining them together at their
apex a².
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what I
ciaim is,-
In an incandescent electric lamp, the construction and use of a continuous
incandescent conductor, consisting of two rods or carbons laid or inclined at an angle,
and joined or cemented together at their one end or apex, and at their other end to
the platinum wires or conductors, substantially as herein described in reference to and
shown in the accompanying Drawings.
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