Improvements in or connected with the Holders of Incandescent Electric Lamps.
Year: 1892

page_text: Date of Application, 5th Feb., 1892-Accepted, 19th Mar.. 1892
COMPLETE SPECIFICATION.
Improvements in or connected with the Holders of Incandescent
Electric Lamps.
A communication by Max Fuss, of 991, Dresdener Strasse, Berlin, in the Empire
of Germany, 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 and 323 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 :-
Incandescent lamps are fastened in their holders by a bayonet device or by being
screwed in. Whilst these methods of fastening have the advantage that the incan-
descent lamps can be very quickly inserted in the holders, they have however the
drawback that the lamps may be very easily removed, and, in fact, they are very
frequently removed in easily accessible places.
This invention has for its object a safety device which is easily attached to
incandescent lamps and which prevents their removal and the invention will be best
understood by aid of the accompanying two sheets of illustrative drawings, on
which the attachment device is represented in various modifications.
In the form shown in Figures 1 to 4 on these drawings, a ring C is placed round
the neck B of the holder A, which ring C can turn loosely on the neck B. This
ring C is provided with two slots D which are so adjusted when the lamp is inserted
in the holder, that they coincide with the entrance openings E of the bayonet slots
(Figures 1 and 3). When the lamp is then turned with the pins G in the bayonet
slot, the pins carry the ring C with them and move the same until it assumes the
position shown in Figures 2 and 4, in which the entrance orifices E of the bayonet
slot are covered by the ring. A screw inserted in the ring C is then screwed
against the neck B of the holder so that any movement of the ring becomes
impossible. In the arrangement shown in Figures 1 to 4, the screw F is so
arranged that it stands, after the turning of the ring, exactly before the entrance
opening of the bayonet slot so that when screwed in it engages in the slot. The
screw may however be applied at any other suitable part of the ring. In such a
case it would be preferable to use a pointed screw so as to allow of its firmly
engaging in the neck B of the holder." In order to render still more difficult any
loosening of the screw by unauthorised persons, the head of the screw may be pro-
vided with a groove of a peculiar form so that it can only be turned by means of a
suitably formed peculiar screw driver.
A safety device for incandescent lamps which are screwed into their holders is
shown in Figures 5 to 7. In this case the revolvable ring C placed on the neck of
the holder is provided with two arms H extending upwards, which by means of a
suitable curve embrace the insulating ring J. Two slots L are made in the above
named ring K corresponding to the arms H, in which, when the lamps are screwed
into the holders, the arms H rest. When the lamp is being screwed in, the ring C
can revolve until the lamp becomes firmly fixed. The pointed screw F is then
firmly tightened and thereby any turning of the ring C is made impossible. The
arms engaging in the slots L of the ring K then prevent any unauthorized screwing
out of the lamp from its holder.
A further modification is shown in Figures 8 and 9 for lamps without the ring K.
Instead of this ring such lamps are provided with a simple smooth neck K¹ to
which the thread is directly attached. A loose revolvable ring C is pushed over
this neck K', which ring is provided with two downward pointing projections H³.

page_text: These projections, when the lamp is screwed into the holder, fit into two corre-
sponding slots in the same and thereby prevent any screwing out of the lamp when
the screw F has been tightened.
Still another modification is shown in Figure 10, in which the movable ring C is
dispensed with. In this case the inner thread M of the holder is extended so far
upwards that it projects beyond the insulating ring J in order to allow of a clamp
screw F being inserted therein. This clamp screw is firmly screwed up, when the
lamps have been screwed into the holder, and thus prevents any unauthorised
removal of the lamp from its holder.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed, as communicated to me by'
my foreign correspondent, 1 declare that what I claim is:-
1. The improvements in or connected with holders for incandescent lamps, which,
consist in the employment of a loose revolving ring (C) having slots (D) or
arms (HH), which engage suitable pins (G) on the lamp, or rest in suitable slots
in the holder, or in the lamp, whereby when the ring has been secured by means of
a clamping screw (F) any unauthorised removal of the lamp from its holder will
be prevented, substantially as herein before described and shown.
2. In holders for incandescent lamps, prolonging the inner threaded portion M
of the holder beyond the insulating ring J, and applying to such prolonged portion
a clamping screw F, whereby the lamp after it has been screwed in position may'
be firmly held, substantially as hereinbefore described and shown.
Dated this 4th day of February 1892.
WM. P. THOMPSON & Co.,
Agents for the Applicant.