Improvements in Incandescent Electric Lamps.
Year: 1892

page_text: Date of Application, 6th Dec., 1592-Accepted, 28th Jan., 1893
COMPLETE SPECIFICATION.
Improvements in Incandescent Electric Lamps.
I, EUGENE WALTER APPLEGATE, of No. 1410 Ashland Block, in the City of
Chicago, State of Illinois, U.S.A., Electrician, do hereby declare the nature of the
said invention and in what manner the same is to be performed, to be particularly
described and ascertained in and by the following statement :-
My invention relates to incandescent electric lamps, and its objects are first, to
provide an incandescent electric lamp of which the glass part of the receiver may
be saved and used repeatedly after the filaments are broken or destroyed. Second.
to provide an incandescent electric lamp which dispenses with the necessity of
using platinum leading in wires to connect the wire of the circuit with the filament
of the lamp. Third, to provide an incandescent lamp the receiver of which may
be exhausted from the base thereof, thus leaving the top free from the tip which is
necessitated by exhausting the air at the top of the lamp and subsequently sealing
the glass of the receiver. And in general the object of my invention is to provide
a cheap, economical and efficient incandescent lamp by the novel elements and
combinations hereinafter set forth and described.
In lamps as commonly constructed and used hitherto, the failure of the filaments
necessitates the destruction of the glass enclosing bulbs, because the leading in
wires pass through glass integral with the glass of which the enclosing bulb is made.
In my invention I employ a plug through which are passed the leading in wires,
which plug being of any desired shape or form to suit the various kinds of lamps,
the plug which I employ may be of any suitable material, and it is cemented or
held by pressure and cement to the glass part of the bulb in any suitable manner or
by any suitable means.
My invention will be more readily understood by reference to the accompanying
drawings, of which-
Fig. 1 is an elevation of a lamp embodying my invention.
Fig. 2 is a partial sectional view thereof.
Fig. 3 is a top view of the socket with the protecting cap removed, revealing the
switch.
Fig. 4 is a bottom view of the socket.
Fig. 5 is a top view of the bulb before being inserted into the socket.
Fig. 6 is a top view of a lamp bulb with the terminals arranged in a different
manner from that shown in the preceding views.
Fig. 7 is a sectional view on line x- of Fig. 6, the lower portion of the bulb,
however, being broken away.
Fig. 8 is a detailed view of the thumb piece and switch which may be used in the
socket of my invention.
Fig. 9 is a sectional view of the switch rod.
Fig. 10 is an elevation of a socket which I use in connection with some forms of
lamps.
Figs. 11, 12, 13, 14 and 15 are modifications of the lamp shown in Figs. 1
and 2.
Fig. 16 is illustrative of one method of attaching the carbon filament to the
leading in wires.
Referring now more particularly to Figs. 1, 2, 3, 4 and 5; a bulb a of the usual
form is employed provided with a rim a' encircling its upper end. About this
rim there is passed a cylindrical piece of brass a³ or other suitable spring metal,
having its upper portion shaped into springs a³ a³, which are adapted to pass
over a bead a in the socket b, which bead a' in connection with the aforesaid spring
holds the bulb firmly in place upon the socket.
Di 17

page_text: It will be observed by reference to Fig. 2 that this cylindrical piece of brass a² is
provided with an inwardly projecting rim 6', which engages with the rim a'. This
cylindrical brass piece a is made up of two parts, as shown by dotted lines in
Fig. 1, to enable the rim a² to be put under the rim a¹. Encircling this brass
piece a² is a ring 2 which holds the two parts of the said brass piece a² firmly
about the lamp.
Referring now to Fig. 2, it will be observed that I employ a plug c composed of
some suitable insulating material, which is inserted into the neck of the lamp and
is fastened hermetically to said lamp by oxide of lead, or other suitable cement,
placed between the rim a¹ and the shoulder c¹ of the plug c; the surfaces to be
cemented being roughened to make the adhesion more secure. Above the plug c is
placed a washer c² which is threaded and works within corresponding threads pro-
vided in the cylindrical piece a². When the cement has been put in place, this
washer c² is screwed firmly upon the plug, compressing the cement between said
plug and the lamp, and thus rendering the joint perfectly air tight. This washer c²,
I have mentioned, may be simply a brass ring, or, as shown in Figs. 6 and 7, may
be composed of a solid disk of any material which is absolutely impervious to air,
as compressed mica. In case a ring of brass is used the annular space about the
terminals c³ ³ must be filled in with some compound which will insure a perfectly
air tight connection between said terminals and the plug c. If a solid disk of air-
proof material is employed, the terminals c³ ³ are moulded in the disk in the process
of its construction, thus making the connection between the terminals and the disk
perfectly air tight. A hole is provided in this solid disk, through which a glass
exhaust tube, d' is passed. The leading in wires d² d² end in springs d³ d³, which
springs are adapted to make contact with the terminals c³ ³. The plug used in this
instance must have an upwardly projecting lip e, which will allow sufficient room in
which the springs d³ d³ may play. The plug is cemented to the lamp in the same
manner as is shown in Fig. 2.
Referring to Figs. 2 and 4, it will be observed that the switch socket is provided
with two spring contact plates el e¹, which, as shown in Fig. 2, are adapted to make
connection with the terminals c c³. The lamp shown in Figs. 1 and 2, is provided
with two carbons and four terminals c³ c³, so that when one carbon is consumed, the
socket may be given a quarter turn, thus bringing the contact plates el e¹ in
electrical connection with the terminals of the unused filament. In this manner the
life of the lamp is doubled.
The socket 6 which I employ in connection with my peculiar form of lamp; is of
novel construction, the shell thereof being preferably made of papier maché, although
other materials may be employed, as brass or rubber.
An insulating disk fis employed, to the underside of which are screwed the
aforesaid spring contact plates e¹ e', and to the upper side of this insulating block
are fastened two binding posts f¹ f2, by which connection is made to the two sides
of the circuit.
A switch block g, suitably mounted in a frame 9¹, is employed, which block is
adapted to make electrical connection between the spring hand contact plate i. The
spring is in electrical connection with the binding post f¹, while the plate & is in
electrical connection with one of the spring contact plates, and electrical connection
is made from binding post f' to the other one of the spring contact plates e¹ by
means of a wire k.
In Figs. 8 and 9, I have shown a modification of the thumb piece and switch
block 9.
It will be observed that the shank of the thumb piece is square in cross
section, adapted to fit within a corresponding square recess in the rod 1, to
which the switch block g is immovably fixed. The thumb piece may be readily
removed.
In Figs. 11, 12 and 13 I have shown a lamp of a modified and simpler construc-
tion. In Fig. 11 I have shown a bulb of the usual form with a bulging end m, with
a bead n encircling it. A socket o is provided, which may be constructed in the
same manner as the socket shown and described in connection with Fig. 2, with

page_text: this exception, that the lower portion of said socket terminates in springs o¹. The
lamp upon being inserted in the socket is securely held therein by means of the
bead n making a firm engagement with the springs o'.
The diameter of the plug c is enough smaller than the interior diameter of the
contiguous portion of the lamp to permit of some hermetic cement to be placed
between said plug and the lamp, whereby a perfect air tight connection is made.
When the plug is firmly in place, a cement is put in the concave recess provided
in the plug, making a perfect air tight connection between the terminals c³ ³ and
the plug.
In Fig. 12 I have shown a lamp provided with a different sort of plug, the lamp
itself is provided with a shoulder p encircling it, and with an extension p¹, whose
exterior surface is threaded to engage with corresponding threads upon the plug c.
A portion of the plug passes within the bulb, but is of a diameter smaller than
the interior diameter of the extension p', permitting a hermetic cement to be put
between said extension 9 and the glass extension pl.
Hermetic cement is also
placed between the shoulder p and the plug. When the plug c is in place upon the
lamp, cement is put in the cavity about the terminals making air tight joints. The
plug is provided with a bead q', which, when inserted into the socket o makes firm
engagement therewith.
In Fig. 13 I have shown still another form of lamp. The neck r of the bulb is
threaded upon its interior, which threads engage with corresponding threads upon
the exterior of the plug c. Between the shoulder and the neck r is placed cement.
When this plug is screwed down, this cement firmly joins the plug and the glass
bulb; hermetic cement is also employed to make perfect air tight joints between
the terminals and the plug. The plug is provided with a bead which serves
firmly to hold the lamp within its socket.
In Fig. 14 I have shown a lamp of peculiar construction, the bent glass tube s
taking the place of the usual form of bulb. In the open ends of this tube are put
plugs cc in a manner similar to that shown in Fig. 13. Electrical connection is
made to the terminals s's in any suitable manner.
In Fig. 15 I have shown what is known commercially as a railroad lamp. It
consists of a cup-shaped glass vessel t, threaded upon its interior at its upper end so
that a plug c may be screwed in said glass vessel and fastened in a manner similar
to that shown in Fig. 13. Terminals vvare inserted, to which are connected
leading in wires ww, to the lower ends of which is attached the carbon filament x.
Near the plug c is suspended upon the leading in wires, a reflector y.
terminals vv are made to form an air tight connection with the plug, as before
described.
The
In Fig. 16 I have shown a new method of attaching the carbon filament to
the leading in wires. The leading in wire is split up its length for a short
distance. The carbon filament is inserted between the bifurcated members of the
wire and a ring
is brought about said bifurcated portion of the wire, thus
firmly holding the carbon filament in place.
In connection with the lamps shown, it will be seen that I have provided glass
exhaust tubes in the plug, these exhaust tubes being moulded partially within
the plugs during the process of their manufacture, a hole in the plug completing the
connection between the air upon the exterior and the air in the interior of the bulb.
I have found it preferable to exhaust the air from within the bulb by means
of this exhaust tube after the plug has been thoroughly cemented to the bulb.
However, the air may be exhausted from the other end of the bulb.
The plugs may be composed of any suitable material, I have found lava, obsidian,
papier maché, lava and soapstone thoroughly intermixed and compressed, limestone
and mica, to give satisfactory results, or any other material which is not a good
conductor of electricity and which may be solidified and so densely compressed as
to be perfectly air proof, may be used.
For hermetic cement, as I have already mentioned in connection with the lamp
in Fig. 2, I preferably employ oxide of lead. In connection with the lamp shown

page_text: in Fig. 11, I preferably employ wool or spun glass between the plug and bulb, and
silicate of soda, shellac or oxide of lead about the terminals.
In the lamps shown in Figs. 12, 13, 14 and 15, I preferably use silicate of soda
and wool or spun glass or oxide of lead. I do not, however, wish to limit myself to
any particular cement.
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is:
1. In an incandescent electric lamp, the combination with a receiver composed of
two parts, one of which parts is glass, of carbon filaments enclosed in said receiver,
leading in wires clamped to said filaments, said leading in wires passing through the
portion of the receiver not glass, an exhaust tube also leading through said part of
the receiver which is not glass, said exhaust tube being adapted to be sealed,
terminals attached to said leading in wires and adapted to make contact with circuit
conductors, and a cement of wool glass and silicate of soda, or equivalent material;
whereby the joint between the two parts of the receiver is hermetically sealed,
substantially as and for the purpose specified.
2. In an incandescent electric lamp, a glass receiver a and a plug c securely
cemented to said glass receiver by any suitable hermetic cement, said plug c being
provided with an upwardly projecting lip e upon which an air-proof non-conducting
disk is adapted to be screwed, terminals cac being moulded in said disk, leading
in wires passing through said plug c and terminating in contact springs d³, said
contact springs making connection with terminals c³, said terminals adapted to
make contact with contact springs el el, said contact springs being mounted upon a
suitable disk f; whereby by the partial revolution of the socket said contact
springs ele are brought into contact with each pair of terminals successively,
substantially as shown and described.
a,
3. In an incandescent electric lamp, the combination of a glass receiver
with a
plug c composed of some non-conducting material hermetically cemented to said
receiver a, leading in wires passing through said plug terminating in the
terminals c³, said terminals adapted to make contact with springs ele', a two part
cylindrical shell a provided with an inwardly projecting shoulder which is
adapted to engage with the shoulder a¹ of said glass receiver a, a band ² surrounding
said two part cylindrical shell a² and holding the same firmly about the lamp, a
threaded washer c² adapted to be screwed upon plug e, metal clips a³ being provided,
whereby the lamp may be securely placed upon the socket, substantially as and
for the purpose specified.
4. In an incandescent electric lamp, the socket 6 having within it an insulating
block upon which is mounted a contact plate i, a switch block g suitably journalled
within the frame g', a binding post forming the terminal of one side of the line
circuit, said binding post being in electrical connection with contact spring h, and
another binding post f being provided which is in electrical connection with one of
the contact springs e', the other of said contact springs e being in electrical
connection with contact plate i; whereby when switch block 9 in its vertical
position circuit is closed from contact spring through plate i, one of the contact
springs e', the carbon filament, and the other of said contact springs e¹ and binding
post to the other side of the line, substantially as specified.
5. In an incandescent electric lamp, the combination with a receiver of two
parts, one of said parts being of glass, of two or more carbon filaments attached to
two or more pairs of leading in wires passing through the part of the receiver not
of glass, and said pairs of leading in wires adapted to be brought in contact
successively with the circuit conductors, whereby when one of said filaments is
broken or consumed another may be brought into circuit, substantially as described.
6. An incandescent lamp of suitable configuration with the stem opening and a
flange stock, a cap adapted to fit within and upon said opening and stock provided 5
with a central tube and two or more projecting carbon clamps, said cap and lamp

page_text: forming an air tight seal, in combination with two or more carbon filaments
removably held within said clamps, all substantially as and for the purpose set
forth.
7. A herein described improved incandescent lamp comprising the bulb and cap
or plug supported by the neck of said bulb and hermetically connected thereto,
the leading in wires extending through said cap or plug and an air exhaust tube
or opening leading centrally through said cap or plug, substantially as set forth.
8. The herein described improved incandescent lamp comprising the bulb, the
lava cap or plug supported thereby, the leading in wires extending through said cap
or plug, a carbon filament connected at its ends to said leading in wires, the exhaust
tube leading centrally through said cap or plug, and a socket removably secured
to said cap or plug and having circuit wires extending therein, substantially as set
forth.
9. The herein described improved incandescent lamp comprising the bulb
provided at its neck with an inner peripheral flange, a cap or plug having a head
at its open end resting on said flange, the leading in wires extended through said cap
or plug, the carbon filaments connected at their ends to said leading in wires, the
removable socket having the circuit wires extending therein, and the plates designed
to engage said electrodes, substantially as set forth.
10. The herein described improved incandescent lamp comprising the bulb
provided at its neck with a peripheral flange, a cap or plug of lava or equivalent
material having a head resting on said flange, the air exhaust tube extending
through said cap or plug, leading in wires having electrodes over their upper ends,
a covering around said electrodes, the removable socket, the contact plates, one of
which is connected to a circuit wire, and a key designed to have connections between
the other circuit wire and the other contact plate, substantially as described.
Dated this 5th day of December 1892.
DAY, DAVIES & HUNT,
321, High Holborn, London, W.C., Agents for the Applicant.