IMPROVEMENTS IN INCANDESCENT LAMPS
Year: 1884

page_text: I JOSEPH SINCLAIR FAIRFAX of No 3 Saint Pauls Road, Camden Town, in the
County of Middlesex, Consulting and Electrical Engineer, do hereby declare the
nature of said Invention for "IMPROVEMENTS IN INCANDESCENT LAMPS" to be as
follows:-
Incandescent lamps are usually made of a bulbous or pear shape, the carbon
filament or light giving agent within, being of a loop form, either plain, coiled, or
convoluted; the two connections being made at one end of the lamp.
By this Invention the glass envelope is made of a parallel tube, or one approxi-
mating thereto; thus dispensing with the blowing now required in the ordinary
form of lamp. This tube may be plain or ornamental, straight or curved, as
desired.
The carbon filament is arranged so that the connections are made one at each
end of the tube, whether the latter be straight or curved. The carbon may be
solid or tubular in section, and either straight, twisted, or covoluted in form.
The filament is attached at each end to a suitable conductor, such as platinum,
and the latter is then securely sealed within a small glass tube or rod. The outer
end of the metal conductor is enlarged or attached to a suitably shaped piece of
copper or silver, placed in position within the tubular glass envelope before
mentioned, a vacuum formed, and the ends securely sealed.
The end or ends of each lamp is formed with faces, recesses, or projections; so
shaped or disposed that when placed in or upon a suitable holder or circuit con-
nection, and moved endways, or upon its axis, the circuit contact will be made or
broken as the case may be.
By this method, several filaments with their conductors attached, may be placed
in the glass tube forming the lamp, a vacuum produced, and sealed hermetically;
thus greatly reducing the cost of manufacture. Two or more of the filaments may
be sealed within the tube in line, and connected in series or parallel, or two or
more lamps grouped around a centre, and joined up in a similar manner.
The holder is so arranged as to receive the end or ends of the lamp, single, double
or of multiple form; of a conducting or non-conducting material, or both combined;
and suitably arranged to be connected to the circuit.
The ends of the lamps being formed as described, the circuit contact pieces,
(forming the holder, or combined therewith,) are arranged to coincide with the

page_text: metal conductor of the lamp and convey the electrical current to the same by
spring or frictional contact, or the contact resulting from gravity. The contact
pieces may be made separately, or form a part of the socket or holder, when the
latter is made of metal; and so arranged that by the motion of the lamp or the
conducting or contact piece, the current is turned on or off.
The socket or holder for the end of the lamp is made capable of being fastened
in any position at will, or so arranged upon a support or connecting piece at such
a distance apart as will allow the lamp to be held between the same, and a similar
or suitable support or connection; or a socket or holder adapted to carry one end
in the manner already stated, and current conveyed to the other end by means of
a flexible conductor such as a chain, or other suitable device.

page_text: I JOSEPH SINCLAIR FAIRFAX of No 3 Saint Pauls Road Camden Town in the
County of Middlesex, Consulting and Electrical Engineer, do hereby declare the
nature of my invention for "IMPROVEMENTS IN INCANDESCENT LAMPS," and in
what manner the same is to be performed, to be particularly described and
ascertained in and by the following statement:—
Incandescent lamps for electrical currents are usually made of a bulbous or pear
shaped form; the carbon filament or light giving agent within being of a loop
form, either plain, coiled or convoluted, the two connections being made at one end.
of the lamp.
By this Invention the glass envelope is made of a parallel tube, or one approxi-
mating thereto; thus dispensing with the blowing now required in making the
ordinary form of lamp. This tube may, be plain or ornamental, straight or curved,
as desired.
The carbon filament is arranged so that its current connections are made,-one
at each end of the tube,-whether the latter be straight or curved. The carbon or
light giving agent may be solid or tubular in section, and either straight, twisted,
or convoluted in form, and of any convenient size according to the candle power
required. The filament is attached at each end to a suitable conductor such as
platinum, and the latter is then securely sealed within a small glass tube or rod,
which may have any convenient form impressed upon it. The outer end of the
metal conductor is enlarged, or attached to a suitably shaped piece of copper, silver,
or other good conductor; placed in position within the tubular glass envelope before
mentioned: a vacuum formed: and the ends securely sealed.
The end or ends of each lamp is formed with faces, recesses,, or projections, or so
shaped or disposed that when placed in or upon a suitable holder or circuit con-
nection, and moved endways or upon its axis the circuit contact will be made or
broken, as the case may be.
By this method several filaments, with their conductors attached, may be placed
in line within the glass tube from which the lamps are formed; a vacuum pro-
duced, and the several lamps sealed hermetically at the proper points. These are
afterwards separated, and the ends finished; and from the fact of one vacuum
process only being required for several lamps, the cost of manufacture is greatly
reduced. Two or more of the filaments may be sealed within the tube in line, and
connected in series or parallel; or two or more, lamps, in suitable holders, are
grouped around a centre, and joined up in a similar manner,
The holder or frame is arranged to receive the end or ends of the lamp or lamps,
and may be of a conducting or non-conducting material, or of both combined.
When of a conducting material the frame or holder must be in two parts and
insulated from each other, each socket being suitably connected to. the circuit. In
the case of a double or multiple lamp holder or frame, of the same kind of material,
the frame at each end, is likewise insulated from the other, and each formed' or
arranged to receive the several ends of the lamps so that the circuit connection
is made to each end, the whole of the lamps being in parallel.
The ends of the lamps being formed as shown and described, the circuit contact
pieces, (forming the holder, or combined with the same), are arranged to coincide
with the metal conductors of the lamp and convey, the electrical current to the same
by spring or frictional contact, or the contact resulting from, gravity. The contact
pieces, may be made, separately, or, form a part or the whole of the socket or holder.

page_text: when the latter is made of metal; and so arranged that by the motion of the lamp,
or the conducting or contact piece, the current is turned on or off.
The socket or holder for the end of the lamp is made capable of being fastened
in any position at will, or so arranged upon a support or connecting piece, and at
such a distance apart as will allow the lamp to be held between the same and a
similar or suitable support or connecting piece; or a socket or holder may be
adapted to carry one end of the lamp in the manner already stated, and the current
conveyed to the other end by means of a flexible conductor such as a chain, coiled
wire, or other suitable device.
In the drawings the same reference letters in the various Figures refer to like
parts, or to parts having the same function. The three columns. of lamp ends
detailed under the letters A, B, C, denote respectively; section; end elevation;
and plan; of each figure. Glass- is denoted by the letter G; the carbon rod,
filament, or light giving agent, by L; the socket or holder by H; the frame or
support by F; the circuit connection or spring contact piece by S; and the metal
piece attached to the platinum by M.
Fig. 1, A, shows a longitudinal section of one end of a lamp having the extreme
end drawn down; and the metal conductor to which the light giving agent is
attached is brought out and connected to the copper ferrule by soldering or other-
wise. The glass at the extreme end is enlarged so as to retain the ferrule or collar
in place, but with a flat formed upon it-so that a spring contact with the collar can
be made or broken by turning the lamp upon its axis; the spring being made
broad enough to bear upon the glass and the metal. In the end elevation, B, of
the same figure, the flat or facet is shown by the cutting away of part of the circle,
and the collar by dotted lines, and both these features are also shown in the plan C,
of the same figure.
Fig. 2, A, likewise shows a section; B, an end elevation; and C, a plan of one
end of a round ended lamp in which the platinum conductor is brought through
the end of a small eyelet inserted in the glass, and the two metals attached by
solder or other suitable means. The electrical contact may be made in this case
by the frictional contact of a screw working in the bottom of the socket or holder; by
the force of gravity acting upon a weighted metal conductor; or by a pointed bolt,
applied by the tension of a spiral, or other spring.
Fig. 3 has a metal piece partly enclosed in the glass, the ends of which may
slightly protrude beyond the surface of the glass so as to make side contact when
turned; or moved longitudinally: The glass may be cut away at the end also, to
form an end connection if desired.
In Fig. 4, the metal piece is soldered outside to the platinum, and is formed so
as to cross the ends and form a collar around the neck, above which glass projec-
tions are formed in two places; and by their action upon a spring tongue, make
and break contact when the lamp is moved. In Fig. 5 the same general plan is
followed, but the glass projection is brought through a hole at the end, and may
thus displace a suitable contact piece.
In Figs. 6, 7, and 8, attachment is made to copper or other metal washers at the
ends of the lamps by the platinum conductors. A tapering projection of glass is
formed at the end of Fig. 6; and the end of Fig. 8 is not made a right angle, so
that contact is made and broken by revolving the lamp against a suitable contact
piece. A weighted contact piece can be used with Fig. 7; and the glass ground
away in parts, in some cases.
Fig. 9 has two eyeletted metal connections to the, platinum, which is connected
to a cross copper wire. Side screws or spring contact pieces may be used in this
case, thus locking the lamp in position to prevent turning in the socket from
vibration.
In Figa 10 and 11, six lamps are shown grouped around a central frame which
is insulated from the top and bottom metal sockets or holders. The current may
be brought by an inner or outer conductor to the upper range of sockets, and
thence to the lamps by any of the methods described herein; and by a conductor a, -

page_text: in the partial half plan in Fig. 11, to the lower range of sockets; and also thence
to the lamps; thus putting all the lamps in parallel. By turning any of them
around upon their axis in the sockets, the contact is made or broken through the
metal tongues S.
Fig. 12 is a similar arrangement for one or more lamps; the frame F, insulating
the upper and lower metal sockets from each other; the current being conveyed to
the upper one by a metallic chain; and the contact made or broken by the frictional
contact of a screw, S, in the bottom holder.
Fig. 13 shows two lamps made of one piece of glass tubing, having an outside
metallic connection in the centre with the two carbons or other light giving agents;
the latter being in line with each other. The current is conveyed by means of
spring contact makers and holders combined as shown, and coupled in series or
parallel as desired. The right hand end of the lamp tube is formed with a bevelled
end similar to those shown in Figs. 6 and 8, which upon turning, acts upon the end
spring piece, S, to make or break contact with the metal piece M; as previously
described.
Fig. 14 shows a curved tube form of lamp, with an eccentric frictional contact,
engaging with the metal holder connected to the carbon. Figs. 15 and 16 are
simple forms of spring contact pieces and holders combined; and Fig. 17 is a socket
or holder of a non-conducting substance such as wood, glass, or porcelain ; but
having a metal contact maker combined therewith, arranged to make contact either
at the bottom or side of the lamp, or both; the current being conveyed through
the metal bolt at the bottom; or in any other suitable manner."
The carbons or light giving agents shown in Figs. 1 to 6 inclusive, and in Fig. 12,
are either twisted or convoluted. The remaining figures in which carbons are
shown are to represent them as straight or curved filaments, or slender rods, or else
tubes. It is to be understood that the ends of the lamps may be alike or not; and
the contact made or broken at one or more places as desired. Also that I do not
confine myself to the sizes of any of the parts herein shown or described; and that
I may modify the forms, arrangements, or the combinations of many of the parts
set forth, without departing from the principle of action herein stated.
I
Having now particularly described and ascertained the nature of my said
invention, and in what manner the same is to be performed, I declare that what
I claim is
1. An incandescent electric lamp, substantially as, and for the purpose, described.
2. An incandescent lamp having a glass envelope of tubular or cylindrical
form, having attached conductors at or near the ends, substantially as, and for the
purpose, described.
3. One or more sockets or holders of a conducting or non-conducting material,
arranged to receive an incandescent lamp having its sides parallel, or approximating
thereto, substantially as described.
4. A double ended incandescent electric lamp having a socket or holder at each
end, substantially as described.
5. A double ended incandescent electric lamp, having a single filament or light
giving agent, arranged so that its electric connections are made or broken by
turning the lamp upon its axis, substantially as described.
6. A double ended incandescent lamp, so arranged that its electrical connections
are made or broken by sliding the lamp longitudinally, substantially as described.
7. A double ended incandescent lamp combined with one or more sockets or
holders, and so arranged that any relative motion of the lamp or its holder, or
any part of the latter, will make or break the electrical connections, substantially
as described.
8. Making or breaking electrical contact at both ends of a double ended
incandescent lamp, substantially as described.
9. The combination of a double ended incandescent lamp, having a single carbon
or light giving agent, with a spring contact at one, or both ends, substantially as
described.

page_text: 10. A double ended incandescent lamp, made without blowing or enlarging the
glass envelope of the same, combined with a twisted or convoluted carbon, or light
giving agent, substantially as described.
11. The combination of an incandescent lamp of a tubular form, with a carbon
or other light giving filament, rod, or tube, connected at each end to a conductor
partly sealed within glass, but attached at its outer extremity to a metallic contact
piece; substantially as described.
12. An incandescent electric lamp having glass projections, recesses, or facets,
arranged so as to make or break contact, substantially as described.
13. The combination of two or more double ended lamps with their sockets or.
holders in single or multiple form, grouped around a centre insulating the ends;
substantially as described.
14. The combination of two or more carbons, or light giving agents, arranged in
line, and sealed within a glass tube; substantially as described.
15. The method of forming two or more lamps in, or of, a single glass tube, of
cylindrical form, from or during one process of exhausting or producing a vacuum
of air, substantially as described.
16. The method of making two or more incandescent lamps from a glass tube,
without blowing or enlarging the same, substantially as described.
17. The method of making two or more incandescent lamps by sealing the
several filaments or carbons with their conductors attached in line, within a single
glass tube; afterwards separating the lamps, and finishing the ends thereof,
substantially as and for the purpose described.
18. The use of two or more carbons or light giving agents within a straight or
curved glass envelope in line, and each having positive and negative electrical
connections, whereby one or more carbons may be used at will, and the current
conveyed to the carbons either in series or parallel; substantially as described.
19. The combination of one or more tubular incandescent lamps, with a socket,
holder, or circuit connection at each end; a means to make and break electrical
contact; and a frame or support insulating the ends from each other, substantially
as described.
20. The combination of a non-conducting socket or holder with a conducting
contact piece, a double ended incandescent lamp and electrical connections to the
ends of the lamp, substantially as described.
21. The combination of a flexible conductor or conductors with a double ended
incandescent lamp, substantially as described.
22. A spring contact and holder combined, substantially as described.
23. The method of making electrical connection with a double ended incandescent
lamp substantially as described.
24. The several forms and arrangements shown in the drawings, and described,
substantially as and for the purpose specified.
Dated this 12th day December 1884.