Improvements in Sockets and Holders for Incandescent Electric Lamps.
Year: 1896

page_text: Date of Application, 19th Feb., 1896
Complete Specification Left, 21st Dec., 1896-Accepted, 23rd Jan., 1897
PROVISIONAL SPECIFICATION.
Improvements in Sockets and Holders for Incandescent Electric
Lamps.
We, JOHN FRANCIS CLEVERTON SNELL, of King's Road Central Station,
St. Pancras Vestry, Pratt Street, in the County of London, Electrical Engineer,
and ARTHUR HENRY MARTIN FRANCIS and ROBERT SPILSBURY JEFFERY
SPILSBURY, trading as Francis and Spilsbury, of Mansion House Chambers,
20, Bucklersbury, in the City of London, Electrical Agents, do hereby declare
the nature of this invention to be as follows:-
Our invention relates to sockets and holders for incandescent electric lamps,
and is especially designed for lamps used on high voltage circuits, the objects being
to construct the parts in such manner as to minimise the liability to and render
practically impossible arcing or short circuiting and shocks to persons, and at the
same time to ensure good and reliable contact at the terminals. In holders as
beretofore constructed the main defects particularly found when used on high
voltage circuits are that the arrangement in close proximity of the poles often
causes disastrous short circuits; also by increasing their distance apart the poles
necessarily come so near to the metal case of the holder as frequently to cause
short circuit by arcing from poles to case; and further in 3-wire systems very
heavy shocks (even up to 400 volts) may be received by a person handling the
holders.
The aim of our invention is to remedy these defects, and to this end according
to our improvements we employ two metallic contact springs arranged at the two
extremes of a diameter of the holder and socket, and we adopt for the casing
porcelain or other good insulating material and provided with a cross bridge piece
passing between and completely separating the contacts. The socket consists of
a collar composed entirely of porcelain or the insulating material and having in
its walls at two diametrically opposite points slots through each of which passes
and is secured on the outer side of the collar a metallic strip or stamping having
a raised or swelled part near its base preferably of some resiliency; the lamp
globe is inserted and its contact wires from the filament connected to each side
strip, and the collar is filled up solid with the usual or suitable filling.
The holder for this socket consists of a containing cylinder and a base plate
with an internal cross bridge piece of suitable height, all of porcelain or other
insulating material, and held together and furnished with the usual or any
suitable external screwed rings, leading in tube, and so forth. The leading in
wires pass through holes in the base plate and are connected at opposite sides
of the cross bridge to the terminals of the two above mentioned metallic contact
springs which are arranged at the extremes of a diameter and hence at the
maximum distance apart and as near as possible to the enclosing porcelain casing.
The contact springs are carried up and bent over and formed with embossed slots,
grooves, or depressions of such form and kind as to receive and closely fit and
hold in metal to metal contact the metallic swelled stampings on diametrically
opposite sides of the socket above referred to, so that when sprung together
perfect electrical contacts are assured and the lamp securely held in position.
Dated this 19th day of February 1896
J. C. CHAPMAN,
Agent.

page_text: COMPLETE DE FUIFICATION,
Improvements in Sockets and Holders for Incandescent Electric
Lamps.
We, JOHN FRANCIS CLEVERTON SNELL, of King's Road Central Station,
St. Pancras Vestry, Pratt Street, in the County of London, Electrical Engineer,
and ARTHUR HENRY MARTIN FRANCIS and ROBERT SPILSBURY JEFFERY
SPILSBURY, (trading as Francis & Spilsbury), of Mansion House Chambers,
20, Bucklersbury, in the City of London, Electrical Agents, 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 sockets and holders for incandescent electric lamps,
and is especially designed for lamps used on high voltage circuits, the objects
being to construct the parts in such manner as to minimise the liability to and
render practically impossible arcing or short circuiting and shocks to persons, and
at the same time to ensure good and reliable contact at the terminals. In holders
as heretofore constructed the main defects particularly found when used on high
voltage circuits are that the arrangement in close proximity of the poles often
causes disastrous short circuits; also by increasing their distance apart the poles
necessarily come so near to the metal case of the holder as frequently to cause
short circuit by arcing from poles to case; and further in 3-wire systems very
heavy shocks (even up to 400 volts) may be received by a person handling the
holders.
The aim of our invention is to remedy these defects, and to this end according
to our improvements we employ two metallic contact springs arranged at the two
extremes of a diameter of the holder and socket, and we adopt for the casing
porcelain or other good insulating material and provided with a cross bridge-
piece passing between and completely separating the contacts.
We will now describe the details of our improved construction in reference to
the accompanying drawings, in which Fig. 1 is a side elevation, and Fig. 2 a
vertical section at right angles to Fig. 1 of the socket; Fig. 3 is an elevation,
and Fig. 4 a plan, and Fig. 5 a vertical section on line 1-2 of Fig. 4, of the
holder.
Similar letters refer to similar parts in all the figures.
The socket consists of a collar C composed entirely of porcelain or other
insulating material, and having in its walls at two diametrically opposite points
slots c through each of which passes for a convenient distance and is secured on
the outer side of the collar for example as shown a brass or metallic strip or
stamping A having a raised or swelled part a near its base preferably of some
resiliency; the lamp globe L is inserted and its contact wires from the filament
connected to each side strip as in Fig. 2, and the cavity of the collar C is filled
up solid with the usual or suitable filling F.
The holder for this socket consists of a containing cylinder B and a base
plate P upon which latter and preferably integral therewith is formed an internal
vertical cross bridge piece D of suitable height. These parts are all made of
porcelain or other insulating material, and they are held together and furnished
with the usual or any suitable kind of screwed rings such as R R¹ which also
secure the leading-in tube H. The leading-in wires pass up through holes pp in
the said base plate P and are connected at opposite sides of the cross bridge D to
the terminals tt of the two above mentioned metallic contact springs TT. These
are fixed upon the base plate P as near as practicable to the extremes of its
diameter, and hence at the maximum distance apart and as near as possible to
the walls of the enclosing porcelain casing B. These contact springs T T are

page_text: carried up as illustrated and bent over at T¹ and formed with embossed slots,
grooves, or depressions as shown at t¹ of such form and kind as to receive and
closely fit and bold in metal-to-metal contact the metallic swelled stampings a on
diametrically opposite sides of the socket C above referred to.
Thus when the two parts are sprung together, perfect electrical contacts are
assured, and the lamp is securely held in position. There is no liability to
arcing or short-circuiting between the poles tt, nor can any damage occur to the
porcelain casing and parts.
Having now particularly described and ascertained the nature of this inven-
tion, and in what manner the same is to be performed, we declare that what
we claim is :-
1. The improved construction and arrangement of sockets and of holders for
incandescent electric lamps, substantially as and for the purpose above described
in reference to and shown in the drawings.
2. For use with incandescent electric lamps in high voltage circuits, a lamp.
socket of porcelain or equivalent insulating material having external metallic
contact strips such as a a arranged diametrically opposite to each other, a holder
for same comprising a casing and base plate with integral vertical cross bridge-
piece all of porcelain or insulating material, metallic contact springs specially
constructed as specified and disposed one at each side of the bridge and at
diametrically opposite sides of the base plate, the whole being arranged and adapted
for use substantially as and for the purposes above set forth.
DL: 10 3
1000