Improvements in or relating to Electric Lamp-holders, Wall-sockets and the like.
Year: 1897

page_text: 66
PROVISIONAL SPECIFICATION.
Improvements in or relating to Electric Lamp-holders, Wall-sockets
and the like.".
I, HENRY BEVAN SWIFT, of 118 Holborn, in the County of London, Electrical
Engineer, do hereby declare the nature of this invention to be as follows:-
This invention relates to electric lamp-holders, wall-sockets and the like, its
object being to construct these devices in such a manner that the risk of short-
circuiting the poles or terminals, even in circuits of high voltage, is reduced to
a minimum.
According to this invention as applied to incandescent lamps I make a cap c
glass or other material preferably integral with the lamp-bulb at the smaller
end thereof, and provide the cap with two contact studs connected with the
opposite ends of the filament. In the socket is a block or cylinder of insulating
material carrying at the opposite sides widely-separated elastic or flexible contacts
with which the leads are connected, and with which the studs projecting from
the cap of the lamp become engaged in the manner hereinafter referred to. It
is an important feature of this invention that these contacts are situated in
recesses or grooves formed in the outer face of the cylinder and do not project
above its suface, so that there is no risk of the current jumping from one to the
other.
A cavity is formed in one end of the cylinder to receive the cap on the lamp
and is provided with an internal annular groove which at the opposite ends of
a diameter opens upon recesses containing the spring contacts, and at the opposite
ends another diameter, preferably 90° removed from the former, is connected with
longitudinal channels open upon the outer end of the cylinder or block.
In engaging the lamp with the spring contacts the studs on the cap are passed
through the longitudinal grooves into the annular groove, the lamp being then
rotated to move the stud round in the groove into contact with the spring ter-
minals which preferably are recessed
or otherwise so formed as to receive or
securely engage the studs on the lamp. The engagement serves also to securely
lock the lamp to the holder.
Conveniently the block or cylinder is encircled by a collar to which a lamp-
shade may be attached in the usual manner.
A cover or end-piece, preferably of insulating material, placed upon the end of
the cylinder, is screw-threaded or otherwise adapted to engage the outer tube as
aforesaid, and the cylinder is flanged to overlap one end of the tube; the cap.
and tube are engaged by the screw-threads or otherwise and retain the flange of
the cylinder between them; thus a single screw or equivalent serves to keep the
three principal members of which the socket is composed, in proper relationship
to each other. The cylinder or block is suitably bored for the passage of the
conductors to the spring contacts.
The cover may be carried at the end of a flexible conductor or support or borne
by a rigid support. And the cap and studs hereinbefore referred to might,

page_text: instead of being connected to a lamp be connected to a flexible conductor; thus,
assuming the end piece, cylinder, and tube to be similarly carried by flexible
conductors a ready connection for two conductors or two sets of such conductors
is afforded.
Instead of the complete circular groove in the block, bayonet-joints, grooves,
or slots could be employed if desired.
BOULT & WADE,
Agents for the Applicant.
"Improvements in or relating to Electric Lamp-Holders, Wall-sockets
and the like.
I, HENRY BEVAN SWIFT, of 118 Holborn, in the County of London, Electrical
Engineer, do hereby declare the rature 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: —
This invention relates to electric lamp-holders, wall sockets and the like, its
object being to construct these devices in such a manner, that the risk of short-
circuiting the poles or terminals even in circuits of high voltage is reduced to a
minimum, and the highest possible insulation is afforded to the metal parts
carrying the current.
According to this invention as applied to lamp-holders, I use a cap or plug of
glass or other material, preferably integral with the lamp bulb at the smaller end
thereof, and provide the plug with two contact studs placed on the sides, at
the opposite ends of a diameter. These two studs being connected, one to each
end of the filament.
In the socket is a block or cylinder of insulating material carrying at the
opposite ends, widely separated elastic or flexible contacts, with, which the leads
are connected, and with which the studs projecting from the sides of the lamp
become engaged in the manner hereinafter referred to. It is an important feature
of this invention that these contacts are situated in recesses or grooves formed
in the outer face of the cylinder, and do not project above its surface so that the
risk of short-circuiting" or sparking across is reduced to a minimum.
66
*
A cavity is formed in one end of the cylinder to receive the plug on the lamp
and is provided with an internal annular groove which at the opposite ends of a
diameter opens upon recesses containing the spring contacts and at the opposite
ends of another diameter, preferably 90° removed from the former, is connected
with longitudinal channels opening upon the outer end of the cylinder or block.
In engaging the lamp with the spring contacts the studs on the plug are passed
through the longitudinal grooves into the annular groove, the lamp being then
rotated to move the stud round in the groove into contact with the spring terminals
which preferably are recessed or otherwise so formed as to receive or securely
engage the studs on the lamp. The engagement serves also to securely lock the
lamp to the holder.
Conveniently the block or cylinder is encircled by a tube and collar to which a
lamp shade may be attached in the usual manner.
A cover or end piece, preferably of insulating material, placed upon the end
of the cylinder, is screw-threaded or otherwise adapted to engage the outer tube,
and the cylinder is flanged to overlap one end of the tube; the cap and tube are
engaged by the screw-threads or otherwise and retain the flange of the cylinder

page_text: between them; thus a single screw or equivalent serves to keep the three principal
members of which the socket is composed in proper relationship to each other.
The cylinder or block is suitably bored for the passage of the conductors to the
spring contacts.
The cover may be carried at the end of a flexible conductor or support or borne
by a rigid support. And the plug and studs hereinbefore referred to might,
instead of being connected to a lamp be connected to a flexible conductor; thus
assuming the end piece, cylinder, and tube to be similarly carried by flexible
conductors a ready connection for two conductors or two sets of such conductors is
afforded.
Instead of the complete circular groove in the block bayonet-joints, grooves, or
slots could be employed if desired.
In the accompanying drawings:
-
Figure is a view showing a lamp holder and lamp fitted according to my
invention, the holder being in section.
Figure 2 is a vertical section through the insulating block.
Figure 3 is a view of the smaller end of the lamp-bulb with its plug and
contacts.
Figure 4 is a view similar to Figure I, but showing a different form of lamp,
and also a modification in the casing of the holder.
Figure 5 is a side elevation of the insulating block showing one of the contacts.
Figure 6 is a section on the line 6, 6, of Figure 5, looking upwards from the
bottom of the block.
Figures 7, 8, 9, 10, & II, illustrate my invention as applied to a wall socket and
plug.
Figure 7 is a view showing the socket and plug, the socket and plug cover being
in section.
Figure 8 is a side elevation of the plug, and
Figure 9 is a sectional plan on the line 9, 9 of Figure 7.
Figure 10 is a vertical section through the centre of the insulating block.
Figure II is a top plan of the socket with the cover removed.
Like letters indicate like parts throughout the drawings.
A is an incandescent lamp-bulb, having at its smaller end, and preferably
integral with it, a cap or plug B of glass or other material.
If male of glass, vitrite or similar material, the cap or plug B is made solid
at its top or cylindrical part, and is furnished with recesses or slots at opposite
ends of a diameter into which contact studs C may be fixed by means of cement,
or in any suitable manner.
The studs C are made of brass or other suitable material, and may be furnished
with a flange, or with pins at their back surfaces, in order that the cement may
fasten them more securely into their recesses.
The platinum "leading in" wires from the ends of the filament are passed
through openings or holes in the plug, and are severally attached to the contact
studs C.
The lower portion of the cap or plug B is preferably made hollow to receive the
top of the lamp bulb A.
If the plug B is made of glass, it may be made integral with the lamp bulb A
by uniting them by means of a blowpipe; if it is of vitrite or other material, it
may be cemented or otherwise firmly fixed to the lamp bulb A.
In the lamp-holder is a block or cylinder of insulating material D, carrying on
opposite sides, widely separated elastic or flexible metallic contacts E which are
connected to the leads by suitable terminals or binding screws.
A cavity F is formed in one end of the cylinder D to receive the cap of the
lamp, and is provided with an internal annular-groove G which opens at two
opposite points upon recesses H containing the spring contacts E.
At two opposite points in an axial plane, preferably at right angles to that in
which lie the recesses H, the annular-groove G is connectied with the outer end

page_text: of the cylinder D, by two longitudinal channels I, through which the studs 0
pass.
When used with a metal case and cover two small longitudinal grooves J are
also made on the exterior of the cylinder preferably opposite each other in the
same axial plane as the channels I: these grooves fit over two small pins in the
cover piece, and prevent the block from rotating in the exterior case, when the lamp
is inserted.
To engage the lamp with the spring contacts E the studs C on the cap are passed
through the longitudinal grooves I into the annular grooves G; the lamp is then
rotated in order to move the studs round in the groove until they make contact
with the springs E. The latter are preferably recessed or fitted with a small
hole K, so as to receive or securely engage the studs C on the lamp cap; this also
serves to securely lock the lamp in the holder.
The block or cylinder D with the lamp plug and the arrangement of contacts
and grooves may be enclosed in some suitable form of case and cover, or combina-
tion of cases, and may be combined with a switch, or other device for regulating
the current to the lamp if desired.
Two methods of encasing the block are illustrated. Fig. I shows a cover and
case of insulating material.
The block D fits into a cylindrical case L, the block being in this case, made
with a flange D¹ which overlaps the case. The latter is preferably screw-
threaded at the upper part on the outside, and the cover M screwing down upon
it, the flange D¹ of the block D is held firmly in its place. Thus a single screw
or equivalent serves to keep the three principal members of which the socket is
composed in proper relationship to each other. The case L may also be provided
with a screw-thread, and ring N on its lower part, or with some other suitable
device for holding a globe or shade.
The cover M is so formed that when the whole lamp-holder is secured together,
the interior of the cover bites or grips the leads to the contacts, thus forming a
suitable cord grip.
Figure 4 shows a cover M and case L of metal. The cover is provided with
two projecting pins which fit into the grooves J in the block D, and prevent the
laiter from turning. The case is screw-threaded upon the outside, or provided
with some device for fastening it to the cover, and the various parts are put
together in the same way as herein before described for the cover made of insulat-
ing material, except that in this case the flange 11 is not used. The metal case L
is provided with an internal coat of thin insulating material O, and a disc of
similar material is placed between the cover M, and the top of the block D.
One or more holes are made in this disc O₁ to admit the leads to the contacts,
and form a cord grip for them when the whole device is screwed up.
A screwed bush P is fitted into the top of the cover to form a suitable outlet
for the leads when the holder is suspended; on removing this bush the holder
may be readily screwed on to a bracket electrolier or other fitting.
Figures 7, 8, 9, 10, & II show a wall socket and plug constructed in accordance
with my invention. In this, while keeping the same principle of grooves and
contact springs, I prefer to make the studs of the plug in the form of cams and
make a small recess or hollow C₁ at the apex of each cam, which engages with a
projection E2 upon the spring contact. The latter are shaped as illustrated, and
fixed preferably by means of screws to the base of the socket. The projections E²
enter the internal annular groove, and engage with the recess in the cams when
the plug is rotated.
Suitable terminals Q are provided for connections to the leads, and screws,
plates, etc. for the insertion of a fuse or fuses in the usual manner, all the parts
being mounted upon the base R which is furnished with a cover S attached by
means of a screw thread or otherwise.
The plug piece T is fitted with suitable terminals and cord-grip for attachment

page_text: to flexible or other conductors, and with a cover U secured by a screw thread or
otherwise.
It is obvious that if more than two spring contacts are used and a correspond-
ing number of cams are provided in the plug piece, any number of circuits may
be simultaneously connected.
Having now particularly described and ascertained the mature of the said in-
vention and in what manner the same is to be performed I declare that what I
claim is:-
1. An insulating block for an electric lampholder, wall-socket, or the like
having grooves such as H on its exterior, containing spring contacts E, a cavity
such as F, and grooves I and G, the latter opening into the grooves H substan-
tially as described, or illustrated in the accompanying drawings.
2. An electric lamp having a plug such as B integral with the lamp bulb and
provided with contact studs such as C substantially as described.
3. In an electric wall socket or the like a plug such as T having projecting
contacts such as C in the form of cams substantially as described.
4. The combination and arrangement of parts, constituting the completo
electric lamp holder substantially as described and illustrated in Figures I, 2,
and 3, or Figures 4, 5, and 6, of the accompanying drawings.
5. The combination and arrangement of parts constituting the complete
electric wall-socket substantially as described and illustrated in Figures 7, 8, 9,
10, and II, of the accompanying drawings.
Dated this 13th day of October, 1897.
HENRY BEVAN SWIFT,
Boult & Wade,
Agents for the Applicant.