IMPROVEMENTS IN INCANDESCENT ELECTRIC LAMPS
Year: 1883

page_text: LETTERS PATENT to Joseph Wilson Swan of Laureston, Bromley, in the
County of Kent, for an Invention of "IMPROVEMENTS IN INCANDESCENT
ELECTRIC LAMPS
"
PROVISIONAL SPECIFICATION left by the said Joseph Wilson Swan at the
Office of the Commissioners of Patents on the 11th April 1883.
JOSEPH WILSON SWAN of Laureston, Bromley in the County of Kent
"IMPROVEMENTS IN INCANDESCENT ELECTRIC LAMPS"
In the manufacture of Incandescent Electric Lamps, it is usual to employ
platinum Wire as the Conductor which passes through the glass, and is sealed
into it. On account of the great cost of platinum, this wire is made as thin as
possible, and in consequence some trouble has been occasioned by the tendency of
the thin wire to break when bent or strained, during the process of making the
attachment to it of the outward conductor or lamp holder. Now this Invention
consists in overcoming this defect by depositing Copper, or other metal by the well-
known electrotype process around the projecting platinum whether in the form of
a loop-pin, or any other form, so as to strengthen it and facilitate the making a
firm attachment of the lampholders or conductors.
The same object may be effected by means of solder, which is applied to the
protruding platinum so as to increase its strength and facilitates the attachment.
of the external conducting wires, or a plate cap hook or loop of brass or other
suitable metal may be soldered to the protruding Platinum for the purpose of
effecting the same object.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Joseph Wilson Swan in the Great Seal Patent Office on the
11th October 1883.
JOSEPH WILSON SWAN of Laureston Bromley in the County of Kent
"IMPROVEMENTS IN INCANDESCENT ELECTRIC LAMPS"
In the manufacture of Incandescent Electric Lamps it is usual to employ
platinum wire as the conductor which passes through and is sealed into the glass.
On account of the great cost of platinum and with a view of preventing fracture
of the glass this wire is made as thin as possible and in consequence some trouble
has been occasioned by the tendency of the thin wire to break when bent or
strained in the process of making the attachment to it of the outer conductors or
the lamp holder. Now my Invention has for its object the overcoming of this
defect and consists in the application of electro deposition or coating or covering
whereby copper or other suitable metal is deposited or coated around the outward
projecting platinum terminals whether they be in the form of loops or pins or in
any other form so as to strengthen and enlarge them or give them such a shape as
will facilitate the making of a firm attachment or electric contact to or with the
lamp holders or conductors. The same object may be effected by means of solder
or other metal fusible at a low temperature which is applied to the protruding
-platinum so as to increase its strength and give an enlarged surface for the
attachment of the external conducting wires or the lamp holder; or a plate, cap,
hook, or loop of brass or other suitable metal may be soldered to the protruding
platinum for the purpose of effecting the same object.
My Invention may be carried into effect by the following methods. According
to one method I place the lamps in a trough containing a solution of sulphate or
other suitable salt of Copper or other metal with which the coating is to be
effected, and I connect their terminals with the Cathode of a suitable generator of
electricity, an electrode of copper connected with the anode of the generator being
also immersed in the trough after the manner well known in the process of electro
deposition and I allow the deposition of metal to go on until a sufficient additional
strength or enlargement has been given to the lamp terminals.
In strengthening or enlarging or facilitating the connection of the lamp
terminals to the outward conductors by means of a fusible metal instead of by
electro deposition I employ caps of copper, brass or other suitable metal (preferably
plated with silver or nickel) to envelope the platinum terminals of the lamp I
attach these caps by filling them with melted solder or other easily fusible metal,
and after immersing the terminals I allow the same to cool when the terminals
become firmly embedded in the said caps which form nipples or projections by
means of which the olectrical contacts with the outward conductors and also the
attachment of the bulb to the holder can be readily and efficiently attained. It
will be evident that the said caps can take the form of hooks or loops, or the like,
or that simple plates may be used in place thereof.
Having now described and particularly ascertained the nature of my said
Invention and the manner in which the same is or may be used or carried into
effect I would observe in conclusion that what I consider to be novel and original
and therefore claim as the Invention secured to me by the hereinbefore in part
recited Letters Patent is :-
First: The improvement in electric lamps, consisting in strengthening, or
enlarging, the terminals thereof by depositing upon., or covering, or coating, the
said terminals with, an inferior, or less costly, metal, substantially as hereinbefore
described.

page_text: Secondly-The application of the process of electro-deposition to the
strengthening, enlarging, or shaping, of the terminals of electric lamps, so as to
facilitate and improve their connection with the outward conductors and with the
lamp holder, substantially as herein before described.
Thirdly. The improvement in electric lamps, consisting in affixing a cap, plate,
hook, or loop (or the like) of metal to the terminals, in the manner and for the
purpose hereinbefore described.
In witness whereof I the said Joseph Wilson Swan have to this my Specification
set my hand and seal this tenth day of October one thousand eight hundred and
eighty three.
JOSEPH WILSON SWAN (LS.)