IMPROVEMENTS IN INCANDESCENT ELECTRIC
Year: 1882

page_text: LETTERS PATENT to William Hopkin Akester, of Glasgow, in the County
of Lanark, North Britain, Electrician and Engineer, for an invention of
PROVISIONAL SPECIFICATION left by the said William Hopkin Akester
at the Office of the Commissioners of Patents on the 5th April 1882.
WILLIAM HOPKIN AKESTER, of Glasgow, in the County of Lanark, North
Britain, Electrician and Engineer,
LAMPS
"
"IMPROVEMENTS IN INCANDESCENT ELECTRIC
This Invention has for its objects, to facilitate and improve the manufacture of
incandescent electric lamps, to prepare the carbon in an improved manner, and to
strengthen and improve the connections of the carbon with the current wires.
In carrying out the Invention the glass bulb is at first made with a mouth of
sufficient width for introducing the carbon with the two platinum conducting
wires. Hollow projections quite separate from the mouth are made in the sides
of the neck for the wires to pass through, and after inserting the wires the glass
of the projections is fused upon them. The wires, at parts near where the carbon
strip is joined to them are fixed by fusing in the opposite ends of a small glass rod
which serves for keeping them in their proper relative positions and for holding
them by, with a pair of suitable pincers whilst inserting them in the bulb. After
the wires and carbon have been inserted the mouth of the bulb is closed over in a
rounded form.
The ends of the wires are prepared for the attachment of the carbon strip by
being first flattened and then drawn with a small mandril through a die so as to
forin sheathes for the insertion of the ends of the carbon strip. The joints between
the carbon strip and the wires are completed either by applying a paste made with
finely powered carbon and a little gum or other suitable adhesive matter, or by
causing carbon to be deposited on them from hydrocarbon gas or vapor.
To form the carbon strips any vegetable fibres are taken and are subjected to
the action of an extremely concentrated solution of chloride of zinc, being steeped
therein for about two hours, and the temperature of the solution being maintained
at about 120 degrees Fahrenheit. After being washed, a sufficient number of the
fibres to form a strip are drawn together through a lead die by which operation
they are compacted together and hardened. Instead of loose fibres, unsized paper
may be similarly subjected to the action of chloride of zinc, and be subsequently
compressed and stamped out, in suitable shapes.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent and
of an order of the Lord Chancellor filed by the said William Hopkin Akester
in the Great Seal. Patent Office on the 30th November 1882.
له
WILLIAM HOPKIN AKESTER, of Glasgow, in the County of Lanark, North
Britain, Electrician and Engineer "IMPROVEMENTS IN INCANDESCENT ELECTRIC
LAMPS
"
My said Invention has for its objects to facilitate and improve the manufacture
of incandescent electric lamps.
In carrying out my Invention the glass bulb is at first made with a mouth of
sufficient width for introducing the carbon with the two platinum conducting
wires but the subsequent closing of this mouth is made a separate and distinct
operation from that of fixing the wires. The operations are very much simplified
and require much less skill than is needed with ordinary incandescent lamps;
whilst the mouth is closed in a simple manner the closing part being rounded, and
the glass can be easily made of sufficiently uniform thickness to avoid liability to
spontaneous fracture from unequal tension or from changes of temperature.
And in order that my said Invention and the manner of performing the same
may be properly understood I hereunto append a sheet of explanatory drawings to
be hereinafter referred to and representing my improved incandescent electric lamp
and parts relating thereto.
Figure, 1, on the accompanying sheet of drawings is a section of a glass bulb
as made according to one modification and as ready for receiving the carbon.
Figure, 2, represents the carbon and parts to which it is attached as held by a
pair of pincers which is used for introducing the carbon into the bulb. Figure, 3,
is a side view of the pincers. Figure, 4, is a section of the lamp as completed
according to one modification and figure, 5, is a section of a second modification.
In these drawings the same reference numerals are used to mark the same or like
parts wherever they are repeated.
In the modification shown in figure, 1, the bulb, 6, is represented as having the
tube, 7, through which the air is afterwards exhausted, attached to the end
opposite to that formed with the mouth or open-ended neck, 8, for inserting the
carbon. The short platinum wires, 9, for leading the electric current to and from
the carbon, 10, are fused into the opposite ends of a small glass rod, 11, which
holds the wires rigidly in their proper relative positions as is necessary to prevent
fracture of the delicate carbon strip, 10, whilst being placed in position in the
bulb, 6. The pincers, 12, are made with ends, 13, shaped to take hold of the glass
rod, 11, and are fitted with a sliding clip, 14, which when moved towards the ends
holds them close upon the glass rod.
For the purpose of fixing the wires, 9, two hollow, horn like projections, 15, are
formed in the neck, S, of the bulb; and when inserting the carbon, 10, the parts
are manipulated by means of the pincers, 12, so as to cause the outer ends of the
wires, 9, to project through the lateral projections, 15. The ends of the projec-
tions, 15, are next fused and closed on the wires, 9, after which the pincers, 12,
are loosened and withdrawn, and the mouth or open end of the neck, 8, is finally
closed over in a rounded form as shown in figure, 4. The operations on the glass
are such as can be easily effected by a worker having but little skill as a glass
blower. After the bulb, 6, has been exhausted through the tube, 7, the end of the
bulb is sealed and the tube removed in the ordinary way.
If preferred the exhaustion may be effected through the neck 8, instead of
through a tube (7) at the opposite end of the bulb. For this purpose the neck, 8,

page_text: may be made a little longer or with more glass at its end than as shown in
figure, 1; and after the carbon has been inserted and the wires, 9, secured the
neck may be formed or drawn into a small tube for connecting the bulb to
the exhausting apparatus. Figure, 5, represents a lamp as made in this modified
manner.
In my Provisional Specification relative hereto I described an improvement in
preparing the carbon, and an improvement in attaching the carbon to the platinum
wires but having since the date of my application for Letters Patent learned that
the said improvements have been made the subjects of earlier Patents obtained by
others I cannot now make any claim to them.
Having thus particularly described my said Invention and the manner of
performing the same I have to state that I do not restrict myself to the precise
details herein described or delineated but that what I believe to be novel and
original and claim as the Invention secured to me by and in terms of the herein-
before in part recited Letters Patent is :-
1. The improved incandescent electric lamp having the parts formed and combined
or arranged substantially as herein before described.
2. The fixing of the wires (9) of an incandescent electric lamp relatively to each
other by fusing them into the opposite ends of a small transverse rod of glass
substantially as hereinbefore described.
3. The fixing of the wires (9) of an incandescent electric lamp to the bulb by
fusing them into the neck or other part of the bulb by an operation or operations
separate and distinct from the operation of closing the neck or mouth of the bulb
substantially as herein before described.
In Witness whereof I, the said William Hopkin Akester, have hereunto set
my hand and seal this twenty-seventh day of November in the year of
our Lord One thousand eight hundred and eighty-two.
Witness
EDMUND HUNT
Patent Agent.
Glasgow.
W. H. AKESTER. (L.S.)