Improvements in Incandescent Electric Lamps and their Connections or Holders.
Year: 1897

page_text: Date of Application, 5th Feb., 1897
Complete Specification Left, 23rd Nov., 1897-Accepted, 5th Feb., 1898 .
PROVISIONAL SPECIFICATION.
Improvements in Incandescent Electric Lamps and their Connections
or Holders.
(A communication by FREDERICK ROBERTS POPE, of 5, Goltzinsstraat, Venloo, in the
Kingdom of Holland, Electrician.)
I, WILLIAM PHILLIPS THOMPSON, F.C.S., M.I.M.E., of the Agency for Foreign
Patent Solicitors, 6, Lord Street, Liverpool, and 6, Bank Street, Manchester, both in
the County of Lancaster, 118, New Street, Birmingham, in the County of Warwick,
and 322, High Holborn, in the County of Middlesex, Civil Engineer, do hereby
declare the nature of this invention to be as follows:-
This invention relates to electric incandescent lamps and their connections or
sockets.
Originally electric incandescent lamps had and often still have their caps attached
to them by means of plaster. Sometimes the electric lamp becomes loose from the
plaster and is then valueless, in any case the caps and bulbs are useless when the
Jamp is done, as the cost of extracting the plaster or removing the cap therefrom
exceeded in value the two materials when separated. In the prior Patent No. 234395
of F. R. Pope, an arrangement was set forth for enabling the caps and bulbs to be
used a number of times, in which invention the plaster was dispensed with but
involving the use of an annular flange fixed to the lamp inside the clamp. By
the present invention, an improvement in fastening the ends on the glass stem of
the lamp is introduced, dispensing entirely with the use of plaster and the internal
flange aforesaid.
The present invention is carried into effect, by using the glass of the lamp as the
fastening agent, doing away with any metal ring or other means of fastening. One
way of effecting this result is by means of a bayonet joint, for which purpose one or
more bayonet grooves or slits are moulded in the glass stem into which internal
projections or studs on the cap or end fit. The projections enter the bayonet grooves,
and by turning, the two parts become locked so as to prevent withdrawal by a
longitudinal movement. The two parts may then be fastened by means of solder, or
any other suitable substance let into the end of say one of the grooves through an
opening in the cap, thus preventing the parts being accidentally turned to separate
them. The bayonet groove may be moulded in the glass stein in the process of
forming the lamp. Instead, however, of the bayonet groove or slit being in the
glass and the projections in the cap or end, it is obvious that the arrangement can be
reversed, the bayonet grooves in such case being in the cap or end and the projections
on the lamp. Furthermore instead of using bayonet grooves in which the grooves
are longitudinal for parts of their length and transverse the remainder, other forms
of coupling might be used. Thus the grooves or slits might be slanted instead of
being bayonet shaped, or formed in such other manner that by turning, the two
parts become locked and so prevent withdrawal by longitudinal movement.
The fastening can be likewise made by making depressions instead of slits or
grooves and having in the socket two corresponding catches punched out of the sides

page_text: on,
of the said socket, so as to form springs on the inside, so that by putting the socket
the pieces or springs would lock into the depressions in the glass, or they could
be bent into the impressions, the fastening could then be made as before described.
Or by punching two holes in the socket to correspond with the depressions in the
glass, when opposite one another, fill with solder or other suitable material. Or by
fastening or fusing any metal or wire into the glass of the lamp, and passing through
holes in socket, thus fastening the same. Furthermore, the fastening might be
made by having two impressions made in the glass, and two corresponding holes in
the cap, these when in position have a spring or band with two buttons on, fitting
into the holes of cap and impressions in the glass, thereby locking them together.
The band can be half way or further round the socket and can be soldered or sprung
on. When the two holes are opposite the two impressions in glass, the band is then
sprung or soldered on.
In describing the above ways of carrying the invention into effect, it must be
understood that the invention is not confined to these, as alterations may be made
without departing from the principle of the invention, the important feature being
fastening the lamp to the cap by the use of the glass of the lamp and without plaster
or any intermediate metal ring.
Improvements in Incandescent Electric Lamps and their Connections
or Holders,
(A communication by FREDERICK ROBERTS POPE, of 5, Goltzinsstraat, Venloo, in the
Kingdom of Holland, Electrician.)
I, WILLIAM PHILLips Thompson, F.C.S., M.I.M.E., of the Agency for Foreign Patent
Solicitors, 6, Lord Street, Liverpool, and 6, Bank Street, Manchester, both in the
County of Lancaster, 118, New Street, Birmingham, in the County of Warwick, and
322, High Holborn, in the County of Middlesex, Civil Engineer, do hereby declare
the nature of this invention and in what manner the same is to be performed, to be
particularly described and ascertained in and by the following statement:-
This invention relates to electric incandescent lamps or their connections or
sockets. One of the main features of the invention consists in making the metal
cap or contacts for the lamp in such manner that the glass stem can be jointed or
otherwise connected direct to the cap or contacts. This enables the caps and bulbs
to be used a number of times instead of having to throw them away when the
filament is done, thus when the filament is broken, the lamp can be disconnected
from the cap and the bulb re-supplied with a new filament and re-used. The lamp
also can be made cheaper by this invention, and it has the advantage that no
plaster need be necessarily used.
In the prior Patent, No. 2343 of 1895 of F. R. Pope, an arrangement is set forth
for dispensing with the plaster, but involving the use of an annular flange fixed to
the lamp inside the clamp. By the present invention, however, the use of plaster
and the internal flange aforesaid are entirely dispensed with.
:
The invention is best described by aid of the accompanying drawing, in which,
Figure 1 is a view of the lamp body;
Figure 2 is a view of the cap separated therefrom, and
Figure 3 a view shewing the cap and lamp connected.

page_text: In this invention the glass of the lamp itself is used as a fastening agent, thus
doing away with any metal ring or other means of fastening. One-way-of effecting
this is by-means-of a bayonet joint, for which purpose one or more bayonet grooves
or slits A are moulded in the glass stem and one or more internal projections or
studs B are fixed in the cap and fit into these indents or bayonet grooves. The pro-
jections after entering the bayonet grooves are turned till the two parts become
locked in the manner of a bayonet joint, so as to prevent a longitudinal movement.
The two parts may then be fastened by means of solder or other suitable substance
let into the end or bend of one of these grooves through an opening C in the cap.
thus preventing the parts being accidentally turned to separate them. The bayonet
groove may be moulded in the glass stem in the process of forming the lamp.
Instead however, of the bayonet groove or slit being in the glass and the projections
in the cap or end, it is obvious that the arrangement can be reversed, the bayonet
groove in such case being in the cap or end and the projections on the lamp. Fur-
thermore, instead of using bayonet grooves in which the grooves are longitudinal for
parts of their lengths and transverse for the remainder, other forms of coupling such
as for instance the screw might be used, or the grooves or slits might be slanted
instead of being bayonet joint shaped, or formed in such other manner that by turn-
ing, the two parts become locked and so prevent the withdrawal by longitudinal
movement.
The fastening can likewise be made by making depressions instead of slits or
grooves, and having in the socket two corresponding catches punched out of the sides
of said socket so as to act as springs, whereby when the socket is put on, the springy
nature of the material will give and the catches will enter the depressions in the
glass and be locked therein, or they could be bent into the depressions, and the fast-
ening could then be finally made as above described. Or any metal or wire could be
fused into the glass of the lamp and pass through holes in the socket, the metal or
wire fastening the same. Another mode of fastering might be by making two
depressions in the glass, and two corresponding holes in the cap, and when these are
opposite each other, a spring or band with buttons on can be forced into the holes of
the cap and impresses in the glass thereby locking them together. The band can go
half way, or more, than round the socket and can be soldered or sprung on, when the
two holes are opposite the two depressions in the glass. The band is then sprung or
soldered in place.
In describing the above ways of carrying the invention into effect and especially of
fixing the two in place it must not be understood that the invention is confined to
these, as these have simply heen given as illustrations of the numerous ways in which
a cap can be fastened to the glass of the lamp without plaster or an intermediate
metal ring.
In all cases however one point is requisite namely to have a projecting piece on
one of the sockets or the lamp holding into a recess in the other of them so that a
longitudinal pull or the weight of the lamp will not detach it from its socket, another
point in all cases is very desirable, but under some circumstances can be dispensed
with, and that is a soldering device whereby when the lamp is locked in place it is
fixed in the locked position by means of solder. The soldering device alone is apt to
fuse in which case the lamp would fall out of its socket.
Referring now to the electric connections which may be used in the cap, the ends
of the wires of the filament D are moulded in with the end of the glass bulb where it
projects into the cap, or holes may be left in the glass end to allow the ends of the
filament to be passed through, and the holes afterwards closed up or fused, by
the application of heat, leaving the wires projecting at E. To the projecting ends of
the platinum wires, may be soldered the copper wires E¹ which are passed through
holes in the cap. The glass stem of the bulb is then inserted in the cap so that
the stud B fits in the bayonet groove A, and the cap or bulb then turned until the
two parts become locked in the manner of a bayonet joint. The glass and cap are
then fastened by solder. The wires which are left projecting through the holes F
are now soldered to the contact pieces G. The lamp is now complete and can be

page_text: inserted into the holder, the contacts G forming connection with the spring contacts
therein. To separate the bulb froin the cap all that is necessary is to break the
solder that fastens the cap and bulb together, turn one or other slightly to disengage
the stud B from the bayonet groove, and then sever the wire by pulling the cap and
the bulb forcibly apart. To renew the filament when burnt out, the points E
where the ends of the filaments pass through the glass of the bulb are fused, the ends
drawn out and the broken pieces of the filament removed. A new filament can then
be passed in and fused into the glass, and the glass and cap re-connected the same as
- before and re-used.
Having now particularly described and ascertained the nature of the said invention
and in what manner the same is to be performed, as communicated to me by my
foreign correspondent, I declare that what I claim is :-
1. The improvement in incandescent electric lamps and their connections or
sockets, which consists in forming the glass stem with irregularities or irregularity
on its surface and the socket with corresponding and complementary irregularities or
irregularity, whereby the irregularity of the one fits into the irregularity of the other
substantially as described.
2. In combination with an arrangement of socket and lamp substantially as
described in Claim 1, a holder in the socket, a corresponding depression in the glass
of the lamp, and a tongue or solder placed therein, whereby the irregularities in the
surface of the socket and lamp are locked together.
3. The various devices for attaching the socket to the lamp without the use of
plaster or any intermediate metal ring being necessary or used, substantially as
described.
Dated this 10th day of November 1897,
WM. P. THOMPSON, & CO.,
Patent Agents, of Liverpool, Manchester, Birmingham, and London.