An Improvement in Incandescent Electric Lamps.
Year: 1891

page_text: Date of Application, 2nd Sept., 1891
Complete Specification Left, 6th May, 1892--Accepted, 18th June, 1892
PROVISIONAL SPECIFICATION.
An Improvement in Incandescent Electric Lamps.
I, EDWARD ALFRED GIMINGHAM, of The Edison and Swan United Electric
Light Company Limited, Ponders End, in the County of Middlesex, Electrician,
do hereby declare the nature of this invention to be as follows:-
wire.
My invention relates to an improvement in incandescent electric lamps whereby
I am enabled to arrange in one bulb two or more filaments in such manner that
when one filament has become worn out the second filament can easily be placed in
circuit and so on.
For this purpose when two filaments are arranged in one bulb
I arrange the bottom of the lamp with three leading-in wires, the one filament
being attached to the one outer leading-in wire and the centre leading-in wire and
the other filament to the other outer leading-in wire and the centre leading-in
The centre leading-in wire is attached to one of the usual contact plates
and the one outer leading-in wire is attached to the other contact plate. The
second outer leading-in wire is attached to a further contact plate placed
immediately under but insulated from this second contact plate by a very thin
layer or membrane of insulating material. On contact being made so as to allow
a current of electricity to pass through the lamp, it causes only the one filament to
become incandescent owing to the insulation of the contact plate leading to the
one arm of the second filament, but as soon as the first filament has become worn
out, the insulating membrane between the two contact plates is withdrawn or
scraped away so that they come in contact and thus allow the current to pass
through both plates, whereby the second filament is rendered incandescent.
When more than two filaments are placed in one bulb I connect their leading-in
wires to separate contact plates each insulated from the others in such manner chat
each in its turn can be placed in circuit by removing or scraping the insulating
material placed between it and the contact plate attached to the leading-in wire of
the filament previously used.
This invention is specially applicable for lamps used in series, as instead of short
circuiting and so cutting out a lamp altogether when it becomes worn out, the
current of high potential simply short circuits through the thin insulating membrane
above described and causes another filament to become incandescent.
Dated this 2nd day of September 1891
ABEL & IMRAY,
Agents for the Applicant.
COMPLETE SPECIFICATION.
An Improvement in Incandescent Electric Lamps.
I, EDWARD ALFRED GIMINGHAM, of The Edison and Swan United Electric
Light Company Limited, Ponders End, in the County of Middlesex, Electrician,
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:-
My invention relates to an improvement in incandescent electric lamps whereby
I am enabled to arrange in one bulb two or more filaments in such manner that
when one filament is worn out, the second filament can easily be placed in circuit
and so on in succession. For this purpose I arrange the conducting wires as I
shall describe referring to the accompanying drawings.

page_text: Figure 1. is a perspective view shewing the wires for two filaments as they would
be connected to the ordinary contact plates.
Fig. 2 is a section shewing the connections to a contact plate and socket.
I arrange for the lamp three leading-in wires X Y Z the one A of the two
filaments being attached to the one outer wire X and to the middle wire Y and
the other filament B being attached to the other outer wire Z and to the middle
wire Y.
As shewn in Fig. 1. the middle wire Y is attached to one of the usual contact
plates C and the one outer wire X is attached to the other contact plate D. The
other outer wire Z is attached to another contact plate E which is placed
immediately under the plate D but insulated from it by a very thin layer or
membrane of nonconducting material. On the lamp being put in circuit the current,
entering by the contact plate E and issuing by C or conversely, causes only the
one filament B to become incandescent, but when B is worn out, the plate E can
be raised and, the insulating material between the two plates D and E being with-
drawn or scraped away, the plate D which had been previously insulated is now
brought into circuit and thus the other filament A is rendered incandescent.
like manner, when more than two filaments are placed in one bulb I connect their
leading-in wires to separate contact plates each insulated from the others so that
each in its turn can be put in circuit by removing or scraping away the insulating
material from between it and the contact plate for the filament previously used.
As shown in Fig. 2 the middle wire Y is connected by a cross wire G to the
socket H, the wires X and Z being respectively connected to two contact plates D
and E having thin insulating material between them, which, when A is worn out,
may be removed to bring B into circuit.
In
The arrangement shewn in Fig. 2 is specially applicable for lamps used in series,
as, instead of short circuiting and so cutting out a lamp altogether when it is worn
out, the current of high potential simply penetrates the thin insulating membrane
above described and causes another of the filaments to become incandescent.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed, I declare that what 1
claim is
In an incandesccent electric lamp, having several filaments in the one bulb,
connecting the one wire of all the filaments to one contact plate or socket, and
the other wires of the filaments to separate contact plates insulated from each
other by nonconducting material that can be removed or can be penetrated by a
powerful current, substantially as and for the purposes set forth.
Dated this 6th day of Anril 1809
ABEL & IMRAY,
Agents for the Applicant.