IMPROVEMENTS IN THE MANUFACTURE OF INCANDESCENT LAMPS.
Year: 1882

page_text: LETTERS PATENT to Edward Henry Torlesse Liveing of 52 Queen Anne
Street, Cavendish Square in the County of Middlesex, and Charles Vernon
Boys of Wing near Oakham in the County of Rutland for an Invention of
PROVISIONAL SPECIFICATION left by the said Edward Henry Torlesse
Liveing and Charles Vernon Boys at the Office of the Commissioners of
Patents on the 6th January 1882.
EDWARD HENRY TORLESSE LIVEING of 52 Queen Anne Street Cavendish
Square in the County of Middlesex and CHARLES VERNON, Boys of Wing near
Oakham in the County of Rutland "IMPROVEMENTS IN THE MANUFACTURE OF
INCANDESCENT LAMPS.
Our Invention relates to modes of manufacturing incandescent lamps whereby
their expense is reduced or their conducting threads more easily replaced when
damaged or destroyed. In the first class of lamp where cheapness is obtained we
avoid the use of the platinum wires sealed in the glass wbich have hitherto been
employed in vacuous lamps to make electrical connexion with the carbon thread
and the wires outside, and use instead a pair of conducting wires suitably insulated
passing through a narrow tube or tubes sealed on to the globe and we prevent the
entrance of air in to the globe through the tube by partly filling it with well
boiled pitch or other resinous or suitable cement which will not give off sufficient
vapour to injure the lamp. In some cases we fill the tube above the pitch with
plaster of Paris or other rigid cement which prevents the pitch from being gradually
forced up the tube by the atmospheric pressure, and heat the rigid cement to a
sufficient degree to get rid of any moisture which might otherwise gradually
escape and damage the carbon thread. The wires with the thread attached have
been drawn in at the open end of the globe which is then drawn out to a narrow
neck. We exhaust the globe by this neck and seal off in the usual way. To save
the expense of blown globes we sometimes use pieces of ordinary glass tubing
drawn out at each end or with a piece of thermometer tubing sealed on at one or

page_text: both ends. For conducting threads we use any known thread but for small lamps
specially suitable for night lights or for medical purposes we use threads of
capillary coke such as are found in coke ovens. These threads from the small
quantity of heat produced may be attached to the conducting wires by solder for
which purpose they are first electro-plated at the ends with a metal to which
the solder will adhear. More than one such thread may be used without danger
from overheating.
To diminish the conduction of heat from the thread by the conducting wires to
the pitch joint we use several methods. Sometimes we employ a considerable
length of conducting wire twisted or conveniently arranged between the thread
and the cement joint, or we attach to the ends of the conducting wires pieces of
metal of considerable size in close contact with the glass by which means a large
quantity of heat is got rid of, or we fill the inner end of the narrow tube with
mercury which is prevented from making electrical contact with the conducting
wires by reason of their insulating coating but which nevertheless conducts tho
heat to the glass stem and so to the support of the lamp.
In the second class of lamp in which the threads are replaceable we make the
globe with a neck sufficiently wide to admit of the introduction of the conducting
thread and wires and we cement it by pitch or other suitable compound to a
support which may be of metal and form one terminal of the lamp, the other
terininal being insulated and passing through it and the joint made airtight as
described; or which may be of glass or vitreous material and contain the two
conducting wires as described in the case of the cheap lamp. In the second class
of lamp we prefer to exhaust from the same end that the wires enter by. To
effect this we in some cases make one of the wires tubular so that though cemented
in position the air may be pumped out through it and we then seal by inclining
the lamp and so allowing some previously melted pitch or cement in it to run down
and enter the upper orifice of the conducting tube, or we pinch a portion of this
tube outside the lamp and heat it so as to melt some solder which has been
previously placed in the tube, or we exhaust by a narrow glass tube which is
cemented into the base of the lamp by pitch or other compound and seal in the
usual way. Instead of a globe with a neck wide enough to admit of the intro-
duction of the carbon and wires we sometimes use a globe with two narrower necks
in which case the metal pieces cemented on form the two terminals. As with the
cheap lamp so with the replaceablo lamp we use when necessary mercury plaster
of Paris or other suitable materials to prevent the heating or creeping of the cement
as already described.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Edward Henry Torlesse Liveing and Charles Vernon Boys in the
Great Seal Patent Office on the 6th July 1882.
EDWARD HENRY TORLESSE LIVEING of 52 Queen Anne Street Cavendish
Square in the County of Middlesex and CHARLES VERNON BOYs of Wing near
Oakham in the County of Rutland IMPROVEMENTS IN THE MANUFACTURE OF
INCANDESCENT LAMPS
Our Invention relates to modes of manufacturing incandescent lamps whereby
their expense is reduced or their conducting threads more easily replaced when
damaged or destroyed. In the first class of lamp where cheapness is obtained we
avoid the use of the platinum wires which, sealed in the glass, have hitherto been
generally used in vacuous lamps to make electrical connexion with the carbon
thread and the wires outside, and use instead a pair of conducting wires suitably
insulated passing through a narrow tube attached to one end of the globe, and we
prevent the entrance of the air into the globe through the tube by partly filling
the tube with well boiled pitch or other resinous cement which will not give off
sufficient vapour to injure the lamp. We prevent undue heating of the cement
during the burning of the lamp by employing a considerable length of conducting
wire twisted or conveniently arranged between the filament and the cement, and
we sometimes fix to these wires radiators to assist the passage of the heat out of
the lamp. For small lamps we employ capillary coke for the conducting filament
but we do not confine ourselves to its use. In the second class of lamp in which
the threads are replaceable we make the globe with a neck sufficiently wide to
admit of the introduction of the conducting thread and wires and we cement it by
pitch or other resinous compound to a support which may be of metal and form
one terminal of the lamp the other terminal being insulated and passing through
it and the joint mado air tight as described; or which may be of glass or vitreous
material and contain to two conducting wires as described in the case of the
cheap lamp. We exhaust through the support by a vaviety of methods hereinafter
described.
In order that our said Invention may be properly understood we now proceed to
describe in detail the manner in which we carry the same into effect. We inake
the glass work by sealing a piece of narrow tube such as thermometer tube to one
end of a piece of larger glass tube which is wide enough to allow the conducting
wires and thread to pass through it. We then generally blow an egg shaped bulb
on that end of the larger tube to which the narrow tube is sealed. We then heat
the other end of the narrow tube till it becomes soft and slightly enlarge it.
Though a considerablo range in the dimensions and proportions of the glass is
allowable we commonly employ narrow tube about three inches long and one
twentieth of an inch in internal diameter. We prefer a bore of from half to three
quarters of an inch for the wide tube. Any conducting wires that do not easily
melt may be used but we have found iron convenient and economical. We clean
and cut the wire into suitable lengths. We wind one end of each wire, generally
three or four inches, round a needle into a fine helix. We then insulate the
straight portion of the wire. We prefer to use as an insulating material asbestus
paper which we cut into narrow strips and wind around the wire. We then
twist the insulated portions of the wires closely together, and the base helical
portions around but not touching one another and bend up the extremities of these
latter portions to form the sockets for the filament. We sometimes heat the
asbestus covered part to burn out organic matter and remove superfluous

page_text: The
asbestus by rubbing with the fingers. Though we prefer to use asbestus as an
insulator we find that spun glass and mica answer well. We treat the insulation
between the twisted wires by heating and smearing with the resinous cement that
is used to close the narrow tube leaving in general about one inch nearest the
filament untreated. We have found it advantageous to keep this cement hot for a
considerable time for which purpose we place the wires to the proper depth in a
bath of the melted cement. The wire is removed, wiped and allowed to cool.
When we use artificial filaments we make them in the form of a long and narrow
loop, but when we use coke threads we place their ends in the sockets and allow
their natural elasticity to give them their form. We in either case fix the filament
by pressing into the wire sockets against the ends of the filament small wedges
which may be made of iron or other conducting and refractory material, having
previously filled the socket with a pasto made of graphite. When coke threads
are employed we sometimes fix them by electro plating the ends with copper or
other metal to which solder will adhear and solder them to the wire supports.
The equalisation of the threads may now be effected by heating in a hydro
carbon or in any well known way. We pass the wires in at the open end of the
globe and through the narrow tube drawing them down till the filament is in a
suitable position, we then fix them and make a temporary seal by warming
the free end of the narrow tube and touching with a drop of cement.
glass work may now be continued. We draw the open end of the globe down
to a narrow neck leaving a tube which may be attached to the pump in
the usual and well known way but we prefer to draw the end of this tubo
down again and attach to a corresponding socket fixed to the pump by warming
and melting cement between them. We prefer to pump a large number of lamps
at one time. Before attaching a lamp to the pump we heat the stem around the
cemented insulation to a temperature a little above the melting point of the cement
and dip the end into a bath of melted cement and draw the air out of the lamp by
the mouth or otherwise till the liquid cement has risen in the tube to within about
an inch from the globe. We make the cement by well boiling pitch and adding
a small proportion generally about one tenth part of gutter percha. Though we
have found this proportion and mixture to answer well we would have it
understood that any other solid resinous compound that does not give off vapour
or crack may be used. We pump and seal the lamp in any well known way. We
make sockets by fixing around the stem of the lamp a tube of wood or non
conducting material having a shallow saw cut across the lower end using generally
plaster of Paris as cement. We bend the free ends of the conducting wires so as
to lie in the saw cuts and pass up on either side of the socket and press the ends
into small holes near the upper end. These sockets are best made of a length
which covers the stem to within about an inch from the globe. The lamp and
socket made as herein before described are conveniently held in supports which
contain two springs insulated from one another but connected to the leads or
conducting wires. A rib may be attached to the socket which passing down a
corresponding groove in the support ensures the wire terminals of the lamp passing
between the springs.
We make the base of the replaceable lamp of either metal, or glass or vitreous
material. We make it in the form of a very flat funnel grinding the upper
surface quite flat when the neck of the globe is to rest upon it. The neck is also
spread out and ground flat. When the base is of metal we make a central hole in
it which will admit the insulated conducting wire which we fix with the same
cement that we use in the cheap lamp. We wind the upper end into a helix and
attach another wire helix to the top of the base to which we fix the filament as
herein before described. When the base is of glass or vitreous material we pass a
pair of conducing wires through it as described in the case of the cheap lamp.
We fix the globe to the base with cement. We sometimes exhaust through the
conducting wire which is made tubular for this purpose and seal by pinching it
below the lamp and heating around the compressed part sufficiently to melt some

page_text: cement or some solder which has been previously placed in the tube. We sometimes
exhaust through a capillary glass tube which passes through the base by the sido
of the conducting wire and seal in the usual way.
Having described the nature of our said Invention and the manner of carrying
the same into effect we declare that what we consider novel and therefore claim
as the Invention to be protected by the herein before recited Letters Patent is,
First, In an incandescent lamp tho use of capillary coke threads such as aro
found in coke ovens thickened or not thickened by special treatment.
Second, In an incandescent lamp the use of well boiled pitch or resinous cement
in a long and narrow tube containing the conducting wires
Third, In an incandescent lamp the combination of twisted wires or radiators
with a long and narrow cement joint.
Fourth, In an incandescent lamp the combination of replaceable globe, tubular
base and cement joints with or without radiators substantially as hereinbefore
described
In witness whereof we the said Edward Henry Torlesse Liveing and Charles
Vernon Boys have hereunto set our hands and seals this Fifth day of
July in the year of our Lord One thousand eight hundred and eighty two