Improvements in Electric Lamp Holders.
Year: 1897

page_text: Date of Application, 4th May, 1897-Accepted, 5th June, 1897
Improvements in Electric Lamp Holders.
I, EDWARD LIONEL JOSEPH, of 92, Queen Victoria Street, in the City of London,
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, and accompanying drawing, that is to say :-
My present invention relates to the holders ordinarily used for incandescent electric
lamps, in which the neck of the lamp is provided with a bayonet joint by which it can
be readily attached to, or detached from, the holders by which it is carried, provision
being made by which when the lamp is fixed in its place, the terminals connected with
the incandescent filament are automatically brought into secure electric contact with
the insulated poles of the conducting wires in the holder. For this purpose it is
usual to fit in the lower end of the holder a disc of suitable insulating material to the
lower side of which are screwed two metal sockets containing spring plungers or
contact pieces, which project downward and are arranged in such a position that when
the lamp is fixed in its place the terminals in its neck press against and make perfect
metallic electric contact with the spring plungers.
Upon the upper part of each of the metal sockets described is formed a lateral
projection having a hole through it to receive one of the conducting wires which is
passed down through the upper part of the holder, and through a corresponding hole
in the insulating disc which carries the sockets.
The wires are firmly held in the lateral projections which receive then, by means of
screws screwed through the latter from the side.
It is evidently essential that the two sockets, with their lateral projections, screws,
and conducting wires, should be absolutely insulated from each other and form the
side of the metallic chamber in which they are fitted, without the possibility of their
coming in contact, and to ensure this insulation, I use a separate insulator of porcelain
or other suitable insulating material, consisting of a circular plate of such diameter as
to fit freely in the inside of the lower part of the lamp holder. This separate insulator
has through it two openings, each of such size and shape as to fit freely round one of
the sockets, and its lateral projection, a recess being also left to receive the head of the
screw by which the conducting wire is fixed in its place. The remainder of the
separate insulator serves therefore to keep entirely separate the two sockets and
the part connected with them and the insulating disc is of such thickness that whilst
its upper face is in contact with the lower side of the insulating disc to which the
sockets are fixed its lower face is in such position that it just allows the spring contact
plungers to project downward through it sufficiently.
Absolute and complete separation and insulation of the sockets and their appendages
is effected, whilst when it is required to release or tighten the conducting wires it is
only necessary to unscrew the lower end of the lamp holder, which can be removed,
together with the separate insulator, and easy access can then be got to the heads of the
tightening screws.
The accompanying drawing is in illustration of my invention. Figure 1 is a plan
from below of the insulating disc and the sockets attached to it. Figure 2 is a similar
view with the separate insulator in place. Figure 3 is a side view of the same,
showing the separate insulator in section. Figure 4 is a plan of the separate insulator,
and Figure 5 a vertical section through the line -y in Figure 4. Figures 6 and 7
show a somewhat modified form of the separate insulator, and Figure 8 is a side view
of the entire lamp holder.

page_text: a is the disc of insulating material, to which are scrowed the sockets b, b', containing
plungers c, c, which are forced outward by springs in the sockets. d, d', are lateral
projections upon the sockets b, b, having holes e, e¹, to receive the ends of the
conducting wires, and screws f,, by which the wires can be fixed or released. is
the separate insulator, having through it openings h, 4, (Figure 4) which fit freely
round the base of the sockets d, d', as shown in Figure 2. The insulator is of such
thickness that when in its place the lower ends of tho plungers c, c', project through
it, as shewn in Figure 3.
In Figures 6 and 7 the openings h, h, through the outer side of the separato
insulator 9 are made circular, so as to fit round the sockets d, d', the inner part only
of the openings g, being of the shape shown in Figure 4.
The separate insulator 9 may be made in two or more parts, instead of one as
shown.
By my invention the insulation of the conducting wires and terminals in the lamp
holder is made absolutely certain, and the possibility of accidental contact and short
circuiting is prevented.
I do not confine myself to the precise details, of shape and proportion, and of
construction, which may be varied to suit varying circumstances, but
Having now particularly described and ascertained the nature of my said
invention, and in what manner the same is to be performed, I declare that what
I claim is
1. In electric lamp holders, the separate insulator g fitting in the holder, and having
through it openings h, h, fitting freely the sockets b, b', the lateral projections d, di
and the screws,, substantially as and for the purpose described and illustrated.
2. The method of making the separate insulator g, described and claimed in
Claim 1, with the openings h, h, of the shape shown, through its inner side only,
these openings at the outer side being circular and fitting round the sockets b, b',
substantially as described and illustrated in Figures 6 and 7.
Dated this 4th day of Nov 1907
EDWARDS & Co.,
65 and 66, Chancery Lane, London, Agents for the Applicant.
EDWARDS & Co.,
65 and 66, Chancery Lane, London, Agents for the Applicant.