Improvements in Electric Lighting Apparatus.
Year: 1891

page_text: Date of Application, 14th Nov., 1891
Complete Specification Left, 12th Aug., 1892-Accepted, 17th Sept., 1892
PROVISIONAL SPECIFICATION.
Improvements in Electric Lighting Apparatus.
I, ROBERT ARTHUR DAWBARN, of 49 Queen Victoria Street, London E.C.
Electrical Engineer, do hereby declare the nature of this invention to be as
follows:-
.This invention has reference to the arrangement of two incandescence electric
lamps in connection with an automatic cut-in device in such a manner that on the
failure of one of the lamps the other will be immediately placed in circuit.
Such a combination can be constructed and arranged in different ways.
According to one arrangement there is an electro-magnet normally in circuit
with one of two incandescence lamps. This electro-magnet when energised lifts an.
armature thereby interrupting the path of the current through the second lamp in
parallel with the first. Conversely when the current ceases to flow through the
first lamp from any cause such as the breaking of its filament, the electro-magnet
will cease to be energised, and consequently the armature will be released and.
dropped upon a contact whereby the circuit will be established through the second
lamp.
According to a modification a solenoid is employed; the current normally
energises the solenoid which lifts a core and interrupts the byepass through the
said lamp but upon the failure of the filament of the first lamp the core drops and
makes contact through a flexible wire and suitable platinum tips with the second
lamp, whilst on the other hand if the "cut-in " is defective the current will pass
through both lamps in parallel.
My invention can be adopted in connection with either a low tension parallel
system of distribution, or a high tension series system, or a multiple series system,
and can be employed with either direct or alternating currents, the electro-magnet
core and armature being suitably laminated in the latter case. It is specially suitable
for street lighting and will permit of the use of the ordinary high-voltage (say
100 volts) lamps as opposed to low-voltage (say 8 volts) lamps in series or multiple
series off high tension mains.
R. A. DAWBARN.
W. Lloyd Wise,
46, Lincoln's Inn Fields, London, W.C., Agent for the Applicant.
COMPLETE SPECIFICATION.
Improvements in Electric Lighting Apparatus.
1, ROBERT ARTHUR DAWBARN, of 45 Queen Victoria Street, London E.C.
Electrical 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 has reference to an improved arrangement of two incandescence
electric lamps in connection with an automatic cut-in device in such a manner that
on the failure of one of the lamps the other will be immediately placed in circuit,
as I will now proceed to explain by reference to the accompanying drawings in
which
Fig. 1 is a diagrammatic view of one arrangement of incandescent electric lamp
and cut-in device according to this invention.

page_text: Fig. 2 shows the cut-in device with the movable parts thereof in different positions
to those shown in Fig. 1.
In this arrangement 1 is the iron core of an electro-magnet having a winding 2
that is normally in circuit with one, say 3, of two incandescence lamps 3 3ª. 4 is
an armature pivotted to one of the legs of the core 1. 55ª are binding posts
between which the incandescence lamps are arranged in parallel. 6 is a movable
contact piece shown in the form of a bent spring that is in connection with the
lamp 3 and the free end of which will move out of contact with the binding post 5*
when the armature 4 is attracted. The arrangement is such that when the lamp 3*
is put in action, the magnet core 1 will be energised and attract the armature 4
into the position shown in Fig. 2 thereby enabling the spring contact to move into
the position shown in Fig. 2 and interrupt the current of the lamp 3ª. When
however the current ceases to flow through the first lamp from any cause, such as
the breaking of its filament, the iron core I will cease to be magnetized and the
armature 4 will consequently be released and will, under the action of gravity,
fall upon the spring contact and cause it to bear upon a contact 7 carried by the
binding post 5, thereby establishing the circuit through the second lamp 3ª as
shown in Fig. 1.
In the modification shown in Fig. 3 a solenoid or coil 2ª with movable core 4ª is
used in lieu of the magnet core 1 and armature 4, and the movable contact 6 is
carried by the core. With this arrangement, when the solenoid or coil is excited
by the current flowing through lamp 3 the core 4ª and contact 6 will be lifted
thereby interrupting the circuit of the second lamp 3ª, but upon the failure of
the filament of the first lamp, the core will drop and cause the movable contact 6
to bear upon the contact 7 and thereby complete the circuit of lamp 3ª through
the conductor 8 a part of which in the arrangement shown is formed into a
spiral spring 8 to permit of the movement of the core 4º. In such case, if the
cut-in device should from any cause be defective, the current will pass through
both lamps in parallel, causing them to glow and thus indicate the defect.
Fig. 4 is a sectional elevation showing a lantern within which are arranged
two incandescence lamps and a cut-in device according to this invention.
My arrangement of lamps and cut-in device can be adapted in connection with
either a low tension parallel system of distribution, or a high tension series
system, or a multiple series system and can be employed with either direct or
alternating currents, the electro-magnet core and armature being in the latter case
suitably laminated. It provides a simple means of burning incandescence lamps
in series groups say for street lighting where the conductors are necessarily
long with a view to economising conductors, and at the same time providing
against the extinction of a whole series group by the failure of one lamp,-say
through the breaking of its filament, by automatically providing for the instan-
taneous re-establishment of the circuit through a second lamp,-preferably arranged
in the same lantern or fitting as shown in Fig. 4, by means of the failure of an
electro-magnet or solenoid to retain an armature or core the dropping of which
ceases to keep out of circuit the said second lamp.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is :-
The arrangement as hereinabove described of two electric incandescence
lamps 3 and 3 placed in parallel in combination with a winding or coil in series
with the one lamp 3 and arranged to excite either a fixed iron core provided
with a movable armature (Figs. 1 and 2) or a movable core (Fig. 3) controlling
a movable contact whereby the circuit of the second lamp 3ª can be completed,
the arrangement being such that whilst the lamp 3 is in operation the armature
or movable core will be held by the action of the current flowing through the
winding or coil in a position such that the circuit of the lamp 3ª will be broken,

page_text: but on the interruption of the circuit of the lamp 3 the armature or movable core
being then no longer attracted will fall and automatically close the circuit of the
lamp 3 as herein before explained with reference to the drawings.
Dated this 12th day of August 1892.
W. Lloyd Wise,
R. A. DAWBARN.
46, Lincoln's Inn Fields, London, W.C., Agent for the Applicant.