IMPROVEMENTS IN AND RELATING TO INCANDESCENT ELECTRIC LAMPS
Year: 1881

page_text: LETTERS PATENT to Joseph Wilson Swan of the Town and County of
Newcastle on Tyne Chemist for an Invention of "IMPROVEMENTS IN AND
RELATING TO INCANDESCENT ELECTRIC LAMPS"
PROVISIONAL SPECIFICATION left by the said Joseph Wilson Swan at the
Office of the Commissioners of Patents on the 29th September 1881.
JOSEPH WILSON SWAN of the Town and County of Newcastle on Tyne
Chemist "IMPROVEMENTS IN AND RELATING TO INCANDESCENT
LAMPS "
ELECTRIC
My Invention relating to incandescent electric lamps has for its object
rendering more perfect the connection between the incandescent Carbon filauient
and the metallic support which conveys the electric current to and from tho same
and also obtaining greater uniformity in the Carbonaceous filaments themselves
and, farther, providing means whereby on the occurrence of rupture of a Carbon
filament in a lamp another filament is automatically brought into circuit.
In carrying out my Invention I place the ends of the Carbon filament in sockets
of platinum or other suitable metal and deposit over the junction of the metal and
Carbon a coating of Carbon, by means of Carbonaceous vapor the filament being
intensely heated locally at the points where the deposit is intended to take place
by the passage of a current of electricity through the filament and conductor. In
order to effect the local heating above referred to 1 electrotype those parts of the
filament which are to be kept cool and on which the said deposit is not intended
to be produced or I accomplish the same object by immersing the said parts in a
metallic bath-In those cases in which the filament is electrotyped I further
promote the cooling of the electrotyped parts by keeping them immersed during
the operation in a bath of oil or other suitablo liquid
In order to produce uniformity in the light giving power of incandescent electric
Lamps the Carbons of which have been strengthened or thickened by heating the

page_text: •
Carbon in a vapor of hydro-carbon or other Carbon-compound I arrange in a
position contiguous to the filament under treatment but not necessarily in the
vessel in which the treatment takes place a thermo-electric contact breaker which
acts in such a manner as to interrupt the passage of the electric current through
the filament under treatment when a standard temperature corresponding to a
certain light giving. power has been attained.
In order to effect the automatic lighting of a second Carbon on the occurrence of
the rupture of the one primarily in action I divide the main wire into two branches
and carry one branch to one end of one Carbon hereinafter designated Carbon N° 1
and the other branch to one end of tho other Carbon hereinafter designated
Carbon No 2 and I connect the other ends of the two Carbons together in one
common conducting wire In one of the said branches I interpose a solenoid or
electro magnetic coil attached to the Lamp stem or contiguous to it and in the
other branch I interpose a mercurial or other contact breaking device so arranged
that while the current is passing through the electro magnetic coil and Carbon
N° 1 the attractive force of the said solenoid or electro magnet shall so.operate as
to cause a break in that branch of the conductor in which the Carbon N° 2 is
placed and therefore prevent the current passing through it so long as the current
is passing through Carbon No 1 but shall on the rupture of Carbon N° 1 allow of
the completing-of-the circuit in-the-branch in which the Carbon No-2 is situate so
as to bring that Carbon into operation

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
29th March 1882.
JOSEPH WILSON SWAN of the Town and County of Newcastle on Tyne
Chemist "[MPROVEMENTS IN AND RELATING TO INCANDESCENT ELECTRIC
LAMPS "
My Invention relating to incandescent electric lamps has for its object
rendering more perfect the connection between the incandescent Carbon filament
and the metallic support which conveys the Electric current to and from the
same
In carrying out my Invention I so to say wold together by means of a deposit
of hard carbon the ends of the filament and the metallic sockets into which the
ends are inserted-My mode of procedure in accomplishing this object is as
follows I make the metallic sockets which receive the ends of the carbon
filament of any suitable metal but preferably of platinum and of a form varied to
correspond with the shape of the filament-If it be a filament of a cylindrical
Section form the ends of the two wires to which the filament is to be attached
into a tube of the size and shape of the end of the filament if the filament be
flattened so that its section is a line of greater or less length then I shape the
sockets so that the ends of tho flattened filament are held between sockets which
are flat surfaces of metal
The sockets having boen formed as described I attach them to a short stom of
glass rod or tubing by fusion by means of a blow pipe so as to be connected
together firmly in pairs and with the sockets in the proper position relatively to
each other to receive the ends of the Carbon filament which is usually of the form
of a loop or arch sometimes with one or more spiral convolutions-Into the sockets
thus arranged I insert the ends of the Carbon arch the Sockets and filaments being
relatively of the proper form so as to fit closely to each other-I then treat the
mounted filaments in one or other of the following ways that is to say-I coat
the filament with copper by the well known electrotype process in every part
except the parts inserted in the sockets and a very short length beyond amounting
to about one millimetre or oven less-After removal from the electrotyping bath
I carefully wash and dry the filament and I then immerse it in a bath of Aniline
Oil Chloroform Benzole Benzolene Olive Oil or any other suitable liquid or vapour
from which carbon deposits by the action of heat and while immersed in one or
other of these liquids-I pass an electric current through the filaments the electric
current being of such strength that the parts of the filaments on which there is no
deposit of copper and also the ends of the sockets and some distance from the
ends of the sockets become so strongly heated that a deposit of carbon takes place
at and upon these parts and I continue the operation until a considerable deposit
of carbon resulting in a bulbous enlargement of the parts on which it has taken
place is produced and the welding together of the sockets and ends of the filaments
already referred to is effected Instead of localising the heating of the parts on
which the carbonaceous deposit is required to take place in the manner described
the same end may be obtained or effected as follows-I immerse the filaments in
a bath of mercury or other suitable liquid metal nearly up to the point of
attachment to the sockets and if a suitable carbonaceous liquid or vapour bills the
bath above the mercury or other suitable liquid metal and an electrical current of
suitable strength as before described is then passed through the connecting wires
and the portion of the filament not immersed the carbonaceous deposit before
described will as before be produced
Or a similar result may be obtained by placing a bridge of metal or carbon in
the nature of a clip formed by two bars of metal or carbon held together by two
slight springs across the Carbon filaments mounted as already described at a point

page_text: very near to the point of attachment to the sockets and so as to divert the current
of electricity from passing entirely through the entire length of the filament and
so as to confine such current to that portion of the filament adjacent to the socket
and which is required to be locally heated-The mounted filament with the
bridging clip across it is then immersed in the carbonaceous liquids or vapours
already referred to and electricity is passed through the connecting wires as
before described and so as to produce the local heating and the required deposit of
carbon
In order to produce uniformity in the light giving power of incandescent electric
lamps the carbons of which have been strengthened or thickened by heating the
carbon in a vapour of hydro-carbon or other carbon compound-I arrange in a
position contiguous to the filament under treatment but not necessarily in the
vessel in which the treatment takes place a thermo-electric contact breaker which
acts in such a manner as to interrupt the passage of the electric current through
the filament under treatment when a standard temperature corresponding to a
certain light giving power has been attained
In order to effect the automatic lighting of a second carbon on the occurrence
of a rupture of the one primarily in action. 1 divide the main wire into two
branches and carry one branch to one end of one Carbon hereinafter designated
Carbon N° 1 and the other branch to one end of the other Carhon hereinafter
designated Carbon N° 2 and I connect the other ends of the two Carbons together
-in-one-common-conducting-wire-In-one-of-the-said-branches-I-interpose-a-solenoid
_or_electro-magnetic coil attached to the lamp stem or contiguous to it and in the
other branch interpose a mercurial or other contact breaking device so arranged
that while the current is passing through the electro magnetic coil and Carbon
No 1 the attractive force of the said solenoid or electro magnet shall so operate as
to cause a break in that branch of the Conductor in which the Carbon Nº 2 is
placed and therefore prevent the current passing through it so long as the current
is passing through Carbon N" 1 but shall on the rupture of Carbon N° 1 allow of
the completing of the circuit in the branch in which the Carbon Nº 2 is situated
so as to bring that Carbon into operation
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 I do not claim as any part of the
Invention secured to me by the herein before in part recited Letters Patent the
means hereinbefore described for producing uniformity in the light giving power
of incandescent lamps neither do I claim the means hereinbefore described for
effecting the automatic lighting of a second carbon on the occurrence of a rupture
of the one primarily in action but what I consider to bo novel and original and
therefore claim as the Invention secured to me by the hereinbefore in part recited
Letters Patent is―
First Producing by means of local electrical heating a coating or deposit of
Carbon over the junction of the metallic socket and the carbon filament inserted
in it
Second In producing the local Carbon deposit above mentioned the application
of metallic deposit by electrical action to the part of the filament required to be
kept cool and on which the carbon deposit is not to take place
In witness whereof I the said Joseph Wilson Swan have to this my Specifica
tion set my hand and seal this twenty third day of March One thousand
eight hundred and eighty two
JOSEPH WILSON SWAN (L.S.)