IMPROVEMENTS IN AND CONNECTED WITH ELECTRIC LAMPS AND IN SWITCHES THEREFOR "
Year: 1882

page_text: LETTERS PATENT to Alfred Fergusson of Southwark in the County of Surrey
for an Invention of "IMPROVEMENTS IN AND CONNECTED WITH ELECTRIC
LAMPS AND IN SWITCHES THEREFOR
"
PROVISIONAL SPECIFICATION left by the said Alfred Fergusson at the
Office of the Commissioners of Patents on the 5th December 1882.
ALFRED FERGUSSON of Southwark in the County of Surrey IMPROVEMENTS IN
AND CONNECTED WITH ELECTRIC LAMPS AND IN SWITCHES THEREFOR
This Invention relates to that class of electric lamps in which the light is formed
in a vacuum and to electric switches by which the current is turned on and off
therefrom
The carbon to be placed in the sealed glass is preferably made from Bass wood
fibre and for the purpose of exposing a large surface of incandescent material when
the lamp is in use said fibre is twisted or looped before being carbonized
For twisting, the fibre is placed over the end of a carbon or other suitable rod
from whence it is kept from slipping by means of pins or projections, it is then
twisted about said rod and subsequently carbonized after which it will retain the
shape of a double spiral with a flat or curved top If a looped carbon is preferred
the fibre is placed over an upper carbon or other suitable rod beneath which its
ends are crossed passing thence under and over two outer rods and being carried
down in a straight line for subsequent attachment to the conducting wires
The fibre is then carbonized in the usual manner and the outlines formed by it
are somewhat similar to that of a three leaved clover If the lamp is to be
suspended from above the wires are sealed in the globe (which is made without a
shank) and are thence carried up outside to the top of the glass and looped or
attached to the conducting wires In either form the carbons may be attached to
the wires by small hollow carbon cylinders or couplings When the lamp is desired
to be supported from below as is now customary, the shank or base of the globe
through which the wires pass, is made solid and projects downward so that it may
be encased in an ornamental ring or support, the bottom of which passes neatly
within the electric switch casing

page_text: The wires leaving the globe are looped, and on the corresponding wires of the
electric switch being hooked therein, the parts are held firmly together If the
current is to be delivered to the lamp by external wires the switch is provided
with suitable terminals in connection with the respective wire hooks which are
embedded in plaster of Paris or other suitable insulating material One wire of
said switch leads directly from the terminal to the corresponding wire of the globe.
The second terminal is attached to a conducting piece or plate embedded in the
plaster of Paris or other insulating material, the circuit being completed by means
of a moveable conducting screw or tap touching said plate after previously passing
through a metal casing to which the second wire hook is attached
If internal wires are deemed preferable, the current is led direct to one of the
wire hooks by means of a wire embedded in insulating material which in turn is
encased in a metal tube or cylinder The circuit in this case being completed by
the moveable conducting screw or tap in electrical connection with the second wire
hook being brought into contact with the metal tube or cylinder, the current in™
this case being "led to earth," by said tube or cylinder being in connection with
the pipes or fittings In either case the circuit to the lamp may be broken by
simply turning back the screw or tap, or where several lamps are on the same
circuit, and it is desired that the turning off of one light shall not effect the other
lamps the conducting wire hooks are placed in direct contact with the terminals
and the carbon, and on the conducting screw or tap being screwed in the current
will pass by the path of least resistance from one terminal to and through the said
moveable conducting screw or tap and out of the lamp by the second terminal
without passing through the lamp, the switch in this case simply forming a portion
of the circuit

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent & of
an Order of the Lord Chancellor filed by the said Alfred Fergusson in the
Great Seal Patent Office on the 27th June 1883.
ALFRED FERGUSSON of Southwark, in the county of Surrey "IMPROVEMENTS IN
AND CONNECTED WITH ELECTRIC LAMPS AND IN SWITCHES THEREFOR "
This invention relates to that class of electric lamps in which the light is formed
in a vacuum and to electric switches by which the current is turned on and off
therefrom. The carbon to be placed in the sealed glass is preferably made from
bass wood fibre and for the purpose of exposing a large surface of incandescent
material when the lamp is in use the said fibre is twisted or looped into various
forms hereinafter described and then carbonized in the usual manner. The fibre is
placed over the end of a carbon or other suitable rod from whence it is kept from
slipping by means of pins or projections; it is then twisted about the said rod and
subsequently carbonized after which it will retain the shape of a double spiral with
a flat or curved top. If a looped carbon is preferred, the fibre is placed over an
upper carbon or other suitable rod beneath which its ends are crossed, passing
thence under and over two outer rods and being carried down in a straight line for
subsequent attachment to the conducting wires, the outline of the fibre will then be
somewhat similar to that of a three leaved clover. The fibre is then carbonized in
the usual manner. The carbons are attached to the wires by small bollow carbon
cylinders or couplings. If the lamp is to be suspended from above, the wires are
sealed in the globe (which is made without a shank) and are thence carried up
outside to the top. of the glass and looped or attached to the conducting wires.
When the lamp is desired to be supported from below as is now customary the
shank or base of the globe through which the wires pass projects downward so
that it may be enclosed in an ornamental ring or support attached to the electric
switch casing. The wires leave the globe either looped or straight and on the
corresponding wires of the electric switch being hooked therein or connected
thereto the globe is held firmly in position in the usual manner. If the current is
to be delivered to the lamps by external wires the switch hereinafter described is
provided with suitable terminals in connection with the respective wire hooks
which are embedded in plaster of Paris or other suitable insulating material. The
current enters the said switch by one terminal which is in direct communication
with the corresponding wire of the globe. The second wire hook is attached to a
conducting piece or plate embedded in the plaster of Paris or other insulating
material, the circuit being completed by means of a moveable conducting screw or
tap touching the said plate after previously passing through a metal casing to
which the return wire of the circuit is connected by the terminal. If internal
wires are deemed preferable the current is led direct to one of the wire hooks by
means of a wire embedded in insulating material which in turn is encased in a
tube or metal cylinder of suitable material. The circuit in this case is completed
by the moveable conducting screw or tap which is in electrical connection with the
external metal tube or cylinder being brought into contact with the second wire
hook, the current in this case being "led to earth" by the said tube or cylinder
being in connection with the pipes or fittings or preferably by means of a second
external wire. In either case the circuit to the lamp may be broken by simply
turning back the screw or tap, or where several lamps are on the same circuit and
it is desired that the turning off of one light shall not affect the other lamps, the
conducting wire hooks are placed in direct contact with the terminals and the
carbon, and on the conducting screw or tap being screwed in, the current will pass
by the path of least resistance from one terminal to and through the said moveable

page_text: conducting screw or tap and out of the lamp by the second terminal without
passing through the lamp, the switch in this case simply forming a portion of the
circuit. In this case a resistance equal to that of the lamp is introduced into the
switch circuit.
In order to enable my invention to be fully understood I will proceed to describe
the same by reference to the accompanying drawing in which figure 1, is a front
elevation of an incandescence electric lamp constructed according to my invention;
figure 2, side view of the carbon of the said lamp; figures 3, and 4, front and side views
of another form of, carbon; figure 5, sectional view on an enlarged scale shewing
the method of connecting the carbons to the wires; figures 6, and 7, sectional
views shewing two arrangements of my improved switch for incandescence electric
lamps where the current is delivered to the lamp by external conducting wires
and figure 8, similar view shewing the conducting wire passing through the
fittings. Similar letters in all the figures represent similar or corresponding
parts.
In figure 1, a, is the usual sealed globe; b,. the carbon connected to the
conducting wires c, by the carbon cylinders or couplings d.. One of these cylinders
or couplings is shewn on an enlarged scale at figure 5, in which figure, d, is the
carbon cylinder the inner periphery of which is of slightly convex form; c, is one
of the conducting wires the upper end thereof being hollowed or cut out. By this
arrangement if the end of the carbon b, and of the wire c, be passed through the
coupling ring d, and the wire pulled down the thicker portion thereof will wedge
the carbon firmly between itself and the coupling so as to connect the. two
together.
e, is the shank of the globe. enclosed in the ornamental ring or support f
connected to the electric switch casing g. Below the shank of the globe the
connecting wires c, are formed with a loop at h, h, as shewn in figures 6, and 7, (or
they may be straight) so that when the wires i, ', of the switch are hooked or
connected to the wires c, c, the parts will be held firmly together.
.
When the current is to be delivered to the lamp by external wires as shewn in
figure 6, the said wires are connected. to the terminals j, j, on the switch casing g,
the terminal j, being insulated from the casing g, by any suitable insulating
material at k,; the wires i, i, are embedded in plaster of Paris or other suitable
insulating material. The wire i, is connected to the terminal j, the other wire i¹,
being connected to a conducting piece or plate 7, embedded in the plaster of Paris;
m, is a moveable conducting screw or tap passing through the casing g, so that
when the said screw is turned inwards so as to touch the said plate l, the circuit
will be completed through the terminal j³, and by turning the screw m, in the
opposite direction so as to remove it from contact with the conducting plate l, the
circuit will be broken.
When internal wires are employed as in figure 8, the current is led direct to one
of the hooks h, by the wire 2, embedded in insulating material encased in the
switch cylinder g, and metal tube n, the circuit is completed by the moveable
screw or tap m, being in electrical connection with the metal tube n, so that when
the circuit is completed the current from the screw m, returns by the said tube n,
being in connection with the pipes or fittings o, or by means of a second internal
wire; p, is an insulator between the tube n, and the fitting o; when the tube n
and the fitting o, are connected by the screw connection r, (or by other suitable
means) the wires i, and q, will be brought into contact by the buttons 8, at the
respective ends thereof.
In the arrangement shewn in figure 7, the conducting wire hooks h, h, are
placed in direct contact with the terminals and on the conducting screw m, being
screwed in, the current will pass by the path of least resistance from the terminal j,
to and through the screw m, and out of the lamp by the second terminal j', without
passing through the lamp, the switch in this case simply forming a portion of the
circuit. In this arrangement it will be obvious that a resistance equal to that of
the lamp must be introduced into the switch circuit.

page_text: Having thus described my invention and the best means with which I am
acquainted for carrying the same into effect I wish it to be understood that what
I claim is:
Firstly. The manufacture and use of the improved carbons for incandescence
electric lamps as hereinbefore described and represented in figures 1, 2, 3 and 4, of
the accompanying drawing.
Secondly. The method herein described of connecting the carbons to the wires of
incandescence electric lamps by the use of hollow carbon cylinders or couplings
substantially as herein before described and represented in figure 5 of the
accompanying drawing.
Thirdly. The improved switch arrangements for incandescence electric lamps
substantially as hereinbefore described and represented in figures 6, 7 and 8 of the
accompanying drawing,
Fourthly. The improved incandescence electric lamps hereinbefore described and
represented in the several figures of the accompanying drawing.
In Witness whereof I the said Alfred Fergusson have hereto set my hand
and seal this twenty seventh day of June in the year of our Lord one
thousand eight hundred and eighty three
FERGUSSON (L.B.)
ALFRED FERGU