Improvements in Holders for Incandescent Electric Lamps.
Year: 1894

page_text: Date of Application, 10th Feb., 1894
Complete Specification Left, 2nd Nov., 1894-Accepted, 8th Dec., 1894
PROVISIONAL SPECIFICATION.
Improvements in Holders for Incandescent Electric Lamps.
We, JULIUS HERMAN GEISENHEINER and ERNEST AUGUSTUS LESSING,
both of 10, Glasshouse Street, Piccadilly Circus, in the County of London
Electrical Engineers, do hereby declare the nature of this invention to be as
follows:-
Our invention relates to holders for incandescent electric lamps and has for its
object to provide means whereby current may be supplied simultaneous or
separately to both the filaments of a double filament incandescent electric lamp.
In applying our invention to a lamp having a screw-cap we provide within the
holder a central contact with which a corresponding stud at the centre of the lamp-
head is designed to make contact, and a side contact with which a ring contact
surrounding the said stud contact is designed to come into contact, the third contact
is formed by the socket into which the lamp-head is screwed. The leading-in
wires are screwed to the said central and side contact and the return wire to the
socket.
In applying our invention to a lamp adapted to be connected to its holder by a
bayonet joint we arrange the contacts in a practically similar manner so that when
the lamp is introduced and turned to fix it the contact plates or surfaces upon the
head of the lamp will bear against the fixed contacts in the holder.
In the case of bayonet capped lamp-holders the holder is preferably made in two
parts insulated from one another and the internal block of insulating material
carries three contacts, two of which serve for the connection of the leading-in wires
and the other for the return wire.
It is obvious that the leading-in wires must be provided with suitable switches
by means of which either or both filaments of a lamp may be placed in circuit.
Dated this 10th day of February 1894.
G. F. REDFERN & Co.,
4, South Street, Finsbury, London, Agents for the Applicants.
COMPLETE SPECIFICATION.
Improvements in Holders for Incandescent Electric Lamps.
We, JULIUS HERMAN GEISENHEINER, and ERNEST AUGUSTUS LESSING,
both of 10, Glasshouse Street, Piccadilly. Circus, in the County of London,
Electrical Engineers, 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 :-
Our invention relates to holders for incandescent electric lamps and has for its
object to provide means whereby current may be supplied simultaneously or
separately to both the filaments of a double filament incandescent electric, lamp.
In applying our invention to a lamp having a screw-cap, we provide within the
holder a central contact with which a corresponding stud at the centre of the lamp
head is designed to make contact, and a side contact with which a ring on the lamp
head surrounding the said stud is designed to come into contact; the third contact
is formed by the socket into which the lamp head is screwed.
In applying our invention to a lamp adapted to be connected to its holder by a
bayonet joint, we arrange the contacts in a practically similar manner so that when

page_text: :
the lamp is introduced and turned to fix it, contact plates or surfaces upon the head
of the lamp will bear against the contacts in the holder.
The holder is sometimes made in two parts insulated from one another, the
block of insulating material carrying three, contacts.
To enable our invention to be fully understood we will describe the same by
reference to the accompanying drawings, in which :-
Figure 1 is an elevation of a lamp-holder carrying a double filament lamp with
a screw-cap; and,
Figure 2 is a central section of the same :
Figure 3 is an underside view of the holder with the lamp removed; and,
Figure 4 is a plan view of the cap of the lamp:
Figure 5 is an elevation; and,
Figure 6 a vertical central section of a lamp-holder carrying a double filament
lamp by a bayonet joint :
Figure 7 is an underside view of the lamp-holder with the lamp removed; and,
Figure 8 is a plan view of the cap of the lamp:
Figures 9, 10, 11 and 12 are views similar to Figures 5, 6, 7 and 8 respectively
illustrating the modification of our invention wherein three contacts are arranged.
upon a block of insulating material.
Similar letters of reference indicate corresponding parts in the several figures.
a is the socket adapted to receive the lamp-head, 6 is the cap of the lamp, and
ed are the two filaments of the latter. e, fare the leading-in wires for the current
for the filaments c, d respectively, g is the common return wire, e, f, g₁ are three
contacts to which the said wires are respectively connected, and e, fare metal
surfaces on the head of the lamp designed when the latter is inserted in the holder
to come into contact with the contact pieces e', f1 respectively.
In the arrangement of our invention shewn in Figures 1 to 4, wherein the head
of the lamp is represented as being provided with a screw-threaded cap adapted to
be inserted into a correspondingly screw-threaded socket, the contact pieces e', f¹
are placed at one side and at the centre respectively of a piece of insulating
material to which they are attached, as clearly shewn in Figure 3, and the metal
surfaces e, f on the head of the lamp designed to make contact with the contact
pieces e, f respectively are, the former, in the form of a ring and, the latter, in
the form of a disc, and so arranged that when the lamp is screwed into the holder
they will always make proper contact when the lamp is screwed home so that there
will be uninterrupted electrical connection through the wire e, contact piece e¹ and
the ring with the filament c and through the wire f, the contact piece f¹ and the
disc with the filament d; the third contact piece 9', which serves as a kind of
distance-piece between the insulating piece and another insulating piece i at the
top of the holder, is in electrical contact with the socket a, and the filaments C₂ d
are both connected with the metal cap 6 of the lamp so that the current after
passing through the filaments will pass through the cap of the lamp to the socket,
thence to the contact g¹ and thence to the return wire g.
It will be readily understood that when suitable switches are placed in the
wires e, the current may be caused to pass through either of the filaments C, d
through both simultaneously.
.
or
1, Figures 1, 2 and 3, is an insulating casing arranged around the socket a in a
well known manner in order to prevent injury to any person handling the bolder
when the current is on.
In the holder shewn in Figures 5, 6 and 7 in which the lamp, is designed to be
fixed by a bayonet joint, the contacts e', f¹ are represented as, being spring-contacts
of the ordinary kind, the sa contacts being fixed to the head i of the holder which
is formed of insulating material at equal distances from the centre, of the said
head. The contact surfaces e³, 12 of the lamp are also arranged at corresponding
distances from the centre of the head so that, when the lamp is introduced into the
holder and turned to lock it therein, the said contact surfaces e, ƒª will be 10
electrical contact with the spring-contacts ef

page_text: In practice we may groove the surfaces e², f' against which the spring-contacts
bear as shewn in Figures 6 and 8 in order to provide a large area of contact
surface.
The third contact 9' is placed on the head i of the holder in such a position
that it will make contact with the metal socket of the holder so that the return
current from the filaments (both of which are connected with the head b of the
lamp) shall pass through the metal socket a of the holder to the contact g¹ and
thence to the wire g. j is a shield which surrounds the socket a and prevents it
from being accidentally touched by the hand, the said shield being insulated from
the socket a by a flange or ring k of insulating material upon which the socket a
with the head i is supported, the cap of the holder being screwed into the shield to
hold the parts in position.
In the arrangement shewn in Figures 9, 10, 11 and 12 we make all three
contacts e, f, g₁ spring-contacts, the two former being arranged as hereinbefore
described whilst the third is arranged at the centre of the head i and, instead of
connecting the filaments to the cap 6 of the lamp, we employ an independent
contact g at the centre of the head of the lamp so that when the latter is introduced
into the holder it will bear against the spring-contact g`.
Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed, we declare that what we
claim is :-
1. A holder for an incandescent electric lamp, with two filaments, wherein there
are three contacts (two of which are for connection to the leading-in wires and one
for connection to a return wire) against which corresponding surfaces on the lamp
head bear, substantially as described.
2. The manufacture and use of holders for incandescent electric lamps
substantially as hereinbefore described and illustrated in Figures 1 to 4, Figures 5
to 8, and Figures 9 to 12 of the accompanying drawings.
Dated the 2nd day of November 1894.
G. F. REDFERN & Co.,
4, South Street, Finsbury, London, Agents for the Applicants.