An Improved Wall Socket and Plug for Electric Lighting and kindred Purposes.
Year: 1895

page_text: Date of Application, 10th Sept., 1895
Complete Specification Left, 10th June, 1896-Accepted, 1st Aug.,
1896
PROVISIONAL SPECIFICATION.
An Improved Wall Socket and Plug for Electric Lighting and
kindred Purposes.
I, GUSTAV BINSWANGER, of 69-71 Queen Victoria Street in the City and
County of London, Electrical Engineer do hereby declare the nature of this
nvention to be as follows :—
known as
My invention relates to an improved form of wall socket of the type generally
"concentric," the poles being concentric, one with the other, consisting
in a metallic ring with a central stud, and the object thereof is to prevent short
circuiting by the accidental or mischeivious insertion of any metal article.
In carrying my invention into effect I employ a base of china, or other suitable
insulating material, preferably of circular form, with a central stem to support the
A metallic
fittings. A hole in said stem serves to support a central contact tube.
sector, having a bent extension, is fastened by a screw to the base aforesaid, said.
screw passing through the stem, and causing the central contact tube to be in
electrical connection with the sector, and a terminal is coupled thereto by means
of a fuse. A ring and bracket with a sector shaped base, formed of one piece of
metal, is attached to the base, the ring portion fitting closely the stem, and
being concentric with the tubular contact herein before referred to, a terminal being
attached to the sector. The two sectors are so disposed upon the base as to be
sufficiently apart from each other, and to occupy about one half of said base. The
other half is used for the attachment of the fuse plate, carrying a terminal for the
lead, and a screw contact for the fuse, which thus bridges the intervening space
between the sector and the fuse plate.
The intervening space between the outer ring and the central contact tube being
filled in with china, or whatever insulating material may be used in constructing
the base, it is practically impossible to insert any metal article to cause a short
circuit. A cover of china or other insulating material is adapted to be screwed
upon or otherwise fixed to the base, and has a central hole to allow of the free
insertion of the contact plug. Said plug has a base preferably formed of china or
like insulating material, to the centre of which is attached a split contact pin, the
screwed end of which passes through the base to the other side, where it is there
screwed into a terminal plate, carrying a terminal for the electric leads, which in
this case are flexible. The base of said plug is shouldered down at its circumference
to receive a short tube of hard metal, having two lugs bent inwards diametrically
opposite each other, said lugs fitting recesses formed in the plug base to receive
them; a screw passing through one lug into the substance forming said base, and
another screw passing through the base and the other lug into a terminal plate,
securing the tube in its place, the shouldered part of the plug base keeping it
concentric with the contact peg; the last mentioned screw serving to connect said
tube with the terminal plate and thence to the flexible lead. The two terminals
When
are preferably separated by a partition formed in or upon the plug base.
the plug is pressed into position, the central split peg fits the central contact tube
on the fixed base, and the tube of the plug fits over the corresponding ring
herein before described, and to ensure perfect contact I may slit the plug tube in
one or more places.

page_text: In this manner I am enabled to construct an electric wall socket and plug that
cannot be tampered with to cause short circuiting.
Dated this 7th day of September 1895.
FREDK.
WALKER,
73 St. Stephen's Road, Upton Park, E.,
Agent for the Applicant.
An Improved Wall Socket and Plug for Electric Lighting and
kindred Purposes.
I, GUSTAV BINSWANGER of Nos. 69-71 Queen Victoria Street, in the City and
County 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:-
My invention relates to an improved wall socket and plug for electric lighting,
power and heating purposes, and more especially the type of wall socket generally
known as concentric, the central connection forming one part consisting of a metal
plug, split or otherwise rendered elastic, and a metal ring concentrically placed
thereto. In such fittings as heretofore made and used, it is possible to cause a
"short circuit" by introducing any conductor within the space between the ring
aforesaid and the plug. The object of my said invention is to obviate this by
interposing an insulating substance or material. between the poles, so that the plug
alone may make contact.
In order that my said invention may be the better understood, I have appended
the accompanying sheet of drawings, in which
Figure 1 is an external plan view, and Figure 2 an elevation of the plug and
socket.
Figure 3 is a plan view of the plug connections, the cover of said plug being
removed and
Figure 4 is a plan view of the base and socket portion of the device, showing the
connections thereof.
Figure 5 is a plan view of the underside of the plug, and Figure 6 is a sectional
elevation of the plug and socket in position of contact as shown by Figure 2.
Similar letters of reference are used, where practicable to indicate corresponding
parts throughout the several views.
In carrying my invention into effect I employ a base A (for the socket,) of china
or other suitable insulating material, preferably circular in form, with a central
stem B of suitable height and diameter which supports the fittings and the socket
cover C. Said stem B is provided with a central hole of suitable depth, which is
'fitted with a contact tube a. A sector shaped plate of metal b (Figures 4 and 6)
with an angular extension bent upwards and shaped to conform to the stem B, is
attached by a screw c or its equivalent to the contact tube a, and the plate is also
attached to the base A, thus establishing electric connection between the plate b afore-
said, and the contact tube a, these being insulated from any other part of the socket,
and a terminal d being either attached directly to the plate b as shown by Figure 6,
or through a safety fusef connecting the plates band e. Figure 4. A ring upon
the stem B is connected to a bracket g with a sector shaped plate, which is attached
to the stem B by screwing or the like. The ring portion fits the stem B tightly
at the upper part thereof, and is therefore concentric with the central contact tube a
but insulated therefrom by the substance of the stem B. A terminal h is attached
to the plate, forming one pole of the socket part of the device. The contact
plates be and 9 are placed sufficiently apart to afford the necessary degree of
insulation. The space between the ring and the contact tube a is filled by the

page_text: insulating substance forming the stem B, so that it is impossible to effect a "short
circuit" by the insertion of a conductor into the socket when the plug is removed,
thus fulfilling the object of my invention. The socket is covered by an insulating
cover C, screwed or otherwise attached to the stem B or the base A, having a
central hole for the insertion of the contact plug, hereinafter to be fully described..
Said plug has a base D, preferably of china or other insulating substance or
material, carrying a split contact pin p which passes through said base D to the
upper side, and is there screwed to a terminal plate m by a screwed nut i said
plate m carrying a terminal k forming one pole of the plug. A ring is fixed to.
the bottom of the base D by screwing or the like, and is electrically connected to a
terminal forming the other pole of the plug. The two conductors of a flexible
lead are connected to the two poles k and j, passing through a hole F in a cover of
china or like insulating substance or material, fitting the base D. The terminals j and k
are connected by a partition o (Figure 3) forming part of, or attached to the base D
of the plug.
In order to afford the requisite degree of elasticity to the ring it is slit at one or
more points in its circumference.
It will be seen that when the plug is placed within the socket, the ring 7 fits upon
the ring or collar and the split contact pin p being concentrically placed also fits.
within the contact tube a, and a high degree of insulation is attained by this
method of construction, since the poles of the plug, comprising the terminals j and k,
ring and contact pin p are perfectly insulated and protected from external injury
by the plug base D and partition o, also the external cover E. Similarly the
socket is insulated and protected by the base A, stem B and cover C, so that no.
contact or "short circuit can be established except by the insertion of the plug,.
constructed as herein described.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is ;-
First. In an improved wall socket and plug for electric lighting and the like,.
the combination of parts substantially as and for the purposes herein described
with reference to the appended drawings.
Second. In an improved wall socket and plug for electric lighting and the like,.
a socket constructed with a base A, stem B and cover C of insulating material, in.
combination with a contact ring r contact tube a, and terminals d and h substantially
as herein described with reference to the drawings.
Third. In an improved wall socket and plug, a plug constructed with a base D,
partition o and cover E of insulating material, in combination with a contact ring 1,.
contact pin p and terminals j and k connected as shown and described,
substantially as and for the purposes herein set forth, with reference to the
appended drawings.
Fourth. In an improved wall socket and plug for electric lighting and the like,.
the construction and employment of an insulating stem B upon the socket, and an
insulating partition o upon the lug arranged in combination with, and relatively to,
the contact rings and r pin and tube a and p and terminals dj k substantially
as and for the purposes herein described with reference to the appended
drawings.
Fifth. The combination of the socket and plug constructed and arranged as
herein described and for the purposes specified.
Dated this 8th day of June 1896
FREDK. WALKER,
73 St. Stephen's Road, Upton Park, London, E.,.
Agent for the Applicant.