IMPROVEMENTS IN THE CONSTRUCTION OF INCANDESCENT LAMPS AND IN SUPPORTS AND ELECTRICAL FITTINGS TO BE USED THEREWITH, WHICH IMPROVEMENTS ARE IN PART
Year: 1883

page_text: LETTERS PATENT to Thomas Tayler Smith of Circus Place, Finsbury in the
City of London, Architect, for an Invention of IMPROVEMENTS IN THE
CONSTRUCTION OF INCANDESCENT LAMPS AND IN SUPPORTS AND ELECTRICAL
FITTINGS TO BE USED THEREWITH, WHICH IMPROVEMENTS ARE IN PART
PROVISIONAL SPECIFICATION left by the said Thomas Tayler Smith at the
Office of the Commissioners of Patents on the 10th August 1883.
THOMAS TAYLER SMITH of Circus Place Finsbury in the City of London,
Architect "IMPROVEMENTS IN THE CONSTRUCTION OF INCANDESCENT LAMPS AND
IN SUPPORTS AND ELECTRICAL FITTINGS TO BE USED THEREWITH, WHICH IMPROVE-
MENTS ARE IN PART APPLICABLE TO ELECTRICAL LIGHTING GENERALLY."
The object of the present invention is mainly to provide increased facilities for
lighting the interions of houses and other structures by incandescent electrical
lamps, but the improvements which I have made for this purpose are in part
applicable to other systems of electric lighting.
With the view of enabling incandescent lamps to be more readily attached to
and detached from their brackets or supports, or to be shifted about from place
to place and used in any desired position, I have devised an improved construction
of incandescent lamp and lamp-holder or support for the same, and simple and
efficient menns for readily attaching the said lamp to its socket upon the said
holder or support, or detaching it therefrom.
I have also devised improved electrical fittings whereby the said lamp and its
lamp holder may be temporarily but securely and efficiently connected with
protected electrical contact surfaces fixed at various points around a room, or.
in other parts of a house or other structure; and an improved safety switch or plug
which when turned to a certain position serves the double purpose of allowing the
current to pass and interposing at the same moment a safety link or bridge-piece
of easily fusible metal.

page_text: In constructing incandescent lamps according to my invention I propose to form
the glass globe with a tubular extension sealed at its inner but open at its outer
end and to connect the platinum or other wires leading from the carbon filament
in the interior of the globe, with metal plates or metallic surfaces attached to or
disposed closely against the inner surface of the said tubular extension, in such
manner that the said metallic surfaces will be protected from touch and will afford
efficient contact surfaces. The tubular extension I prefer to make elliptical in
cross section.
Upon the standard or other lamp-holder or support intended to receive this
improved lamp, 1 form a socket of a size and form to correspond with that of the
tubular extension of the lamp, and within this socket I arrange two tongues of
metal held apart by a spring or springs. These tongues are adapted to enter an
opening in the tubular extension of the lamp when it is placed in position, and
may be brought into close and efficient contact with the metal plates therein by
giving the lamp a quarter turn, suitable stops being provided to facilitate the
adjustment of the lamp to the lighting position. When the lamp is detached, the
springs will be concealed by the socket on the bracket or other lamp support, and
means may be provided for automatically sheathing or covering up the said springs
on the removal of the lamp so as to protect them from accidental touch.
To enable the lamp to be used for various purposes, and especially to adapt it
for bedroom use, 1 mount it upon a support of novel construction which may be
stood upon a dressing or other table and be moved about as required or may be
firmly suspended against a wall or attached to a ledge or other surface, such for
instance. as the top of a looking-glass, so that one lamp may be used in a large
number of places and positions, and-its-general utility thereby greatly increased.
The current of electricity is conveyed to the lamp by a flexible cord or cords...
containing the flow and return wires suitably insulated, and in order to prevent
entanglement of the said cord and the inconvenience arising therefrom I form the
lamp support with a hollow stem adapted to receive the said card and terminating
in a tripod stand or base of such a form as to support the flexible cord or a part
thereof when coiled around it and prevent its trailing about the room or table;
spring clips or cleats being fixed to the lamp holder to facilitate this. The hollow
stem of the lamp support may be made telescopic, spring clips or hand catches,
or equivalent devices, being provided for retaining the telescopic parts in position
when drawn out.
To enable the lamp holder to be steadily supported against a wall, or suspended
without swaying from the upper edge or portion, say of a looking-glass, 1 attach
to the hollow stem or form in one therewith a short bracket ar terminating
above in a loop or eye and below in a point or pin constituting a hook, and I am
thus enabled to suspend the lamp from a nail or hook against a wall or similar
surface, or upon the looking glass, or it may be a picture frame without swaying
and in any desired position.
The free end of the flexible cord leading from this improved lamp holder and
lamp I pass through a knob or plug of vulcanite wood or other insulating material
and secure the strands of the flow and return wires respectively by means of
binding screws to metallic projections attached to opposite sides of the stem of
the knob or plug which is deeply slotted at this part to allow the wires to bo
separated, and out of the way.
The metallic projections are formed with slightly rounded extremities like those
of a key, and are adapted to be inserted in slots of corresponding form in a guard
plate and make contact with curved spring terminals fixed behind the said guard
plate when the knob is turned to a certain position.
When the lamp is required for use it is merely necessary to insert the stem
of the knob or plug with its key like projections in the orifice of the box containing
the fixed terminals and give it a quarter turn whereupon the current if flowing
will pass to the lamp by the wires of the flexible cord.

page_text: A knob or plug with metallic projections on its stem as above explained may be
used as a switch on a single line wire to make or break the electrical circuit, and
in this case the flexible cord will not be necessary and a short piece of lead wire
of suitable resistance may be used as a fusible bridge to connect the two metallic
projections on the stem of the plug thereby combining the advantages and
convenience of a safety plug and an ordinary switch.
The resistance of such a safety switch can be accurately determined and easily
varied, while the lead wire when fused can be instantly renewed; screws or sinall
spring clips being used to secure it rapidly in place.
This simple and efficient removable safety switch it is obvious can be used for
electric installations generally, and it may be combined if desirable with a flexible
cord containing the flow and return wires from a bracket or support for a number
of incandescent lamps.
The spring terminals which I prefer to employ in my electrical fittings I form
out of curved pieces of metal, broad at one end and tapering towards the other.
The broad end is secured to the interior of the socket by a screw or screws which
also connect the ends of the branch flow or return wire to their respective spring
terminals. The tapering end of the spring is bent back upon its curved base and
terminates in a book which enters a notch cut in the guard plate of the socket.
I thus obtain a durable spring of considerable elasticity and the notches into which
the hooked or plain ends of the springs enter or dip, serve as stops for the metallic
key-like projections, and prevent endway strain being thrown upon the spring
terminals. The curved bases of these spring terminals may be held more securely
by causing the guard plate when screwed on or fixed in place, to partly overlie
and nip the said bases. A guide plate serves to direct the course of the keylike
projections and prevents tampering with the springs.
When fittings similar to those above described are used to attach lamps to their
socket the parts will require some slight modification.
The spring terminals may remain substantially the same as those above
described, but the form of the pins or key like metallic projections, and the manner
of fixing the same in the lamp require to be modified to give the pins sufficient
strength and to prevent undue strain being thrown upon the glass of the lamp.
The pins I form of copper wire of about the size known as N° 19 B. W. G., and
I flatten them out to about 1% of an inch broad for a greater portion of their
length, so that when embedded in the glass or in a filling of plaster of Paris or
other cement within the elliptical extension of the lamp, they may be very firmly
gripped by the lanp, and may be used with considerable force without risk of
breaking the glass. The extreme end of each piece of wire is left round or
unflattened, and is bent at right angles to form the key like projection which
engages with the curved spring within the socket.
These pins thus serve as el-ctrical circuit connectors and as locking devices for
retaining the lamp in its socket, at the same time.
To provide for the disconnection of the lamp socket from the end of its hollow
bracket or support without injury to the wires by twisting I make the end of the
bracket square, and the lamp socket I construct of woud or other insulating
material with an aperture of corresponding shape; the flow and return wires being
secured to opposite sides of this socket. The guard plate or cover is screwed onto
the top of the socket, and hence, when the lamp is detached, the guard plate or
cover can be fieely unscrewed and access to the wires be had without twisting
them or injuring them at all.
The wooden socket may be pinned to the square end of the bracket by a
screw passed through both, and can readily be slipped off by slackening the wires
within it.
To enable a lamp fitted with loops of wire to be readily attached to or detached
from the pins or hooks within a socket and to maintain the contact even under
severe vibration and jerks, I use pins of wire partially flattened out as above

page_text: explained to serve as springs and also to afford an efficient base for the attachment
to them of the wires and for securing them to the socket. These pins I arrange
parallel, but out of line, and with their unflattened hooked or bent ends extending
in opposite directions. The loops of wire in the lamp I also arrange parallel
but out of line and by engaging the hooked or bent ends of the spring terminals
with the loops on the lamp I obtain a tight contact. This contact I maintain
by means of small nuts which I screw on the threaded ends of the spring terminals
when the loops are in place thereon.
A sliding sheath serves to enclose and protect the terminals when the lamp is
' removed.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Thomas Tayler Smith in the Patent Office on the 9th February
1884.
THOMAS TAYLER SMITH of Circus Place Finsbury in the City of London
Architect "IMPROVEMENTS IN THE CONSTRUCTION OF INCANDESCENT LAMPS AND
IN SUPPORTS AND ELECTRICAL FITTINGS TO BE USED THEREWITII, WHICH IMPROVE-
MENTS ARE IN PART APPLICABLE TO ELECTRICAL LIGHTING GENERALLY
"
The object of the present Invention is mainly to provide increased facilities for
lighting the interiors of houses and other structures by incandescent electrical
lamps, but the improvements which I have made for this purpose are in part
applicable to other systems of electric lighting.
With the view of enabling incandescent lamps to be more readily attached to
and detached from their brackets or supports, or to be shifted about from place to
place and used in any desired position, I have devised an improved construction of
incandescent lamp and lamp holder or support for the same, and simple and
efficient means for readily attaching the said lamp to its socket upon the said
holder or support or detaching it therefrom.
I have also devised improved electrical fittings whereby the said lamp and its
lamp holder may be temporarily but securely and efficiently connected with
protected electrical contact surfaces fixed at various points around a room, or in
other parts of a house or other structure, and an improved safety switch or plug
which when turned to a certain position serves the double purpose of allowing the
current to pass and interposing at the same moment a safety link or bridge piece
of easily fusible metal. The nature of my several improvements will be understood
from the following description reference being had to the several Drawings
accompanying the same.
In constructing incandescent lamps according to my Invention I form the glass
globe A with a tubular extension a sealed at its inner, but open at its outer end
as shewn in Fig: 1, and connect the platinum or other wires a¹ a', leading from
the carbon filament b in the interior of the globe, with metal plates or metallic
surfaces cc attached to or disposed closely against the inner surface of the said
tubular extension a in such manner that the suid metallic surfaces c c will be
protected from accidental touch and will afford efficient contact surfaces.-The
tubular extension a I prefer to make elliptical in cross section as shewn in Fig: 2
Upon the standard or other lamp holder or support intended to receive this
improved lamp, 1 mount a socket B of any suitable kind to receive the tubular
extension a of the lamp A, and within this socket I arrange two tongues of
metal d d held apart by a spring or springs and preferably by a block of soft
rubber d' as shewn in Figures 3 and 4.
The-e tongues d d are adapted to enter an opening in the tubular extension of
the lamp when it is placed in position and may be brought into close and efficient
contact with the metal plates c c therein by giving the lamp a quarter turn.-I
preferably make the extremities of the tongues cup-shaped, and provide corresponding
Indentations or notches in the plates c c to facilitate the adjustment of the lamp to
the lighting position and prevent its accidental displacement.
When the lamp is detached, the springs will be within the socket B on the
bracket or other lamp support, and means may be provided for automatically
heathing or covering up the said springs on the removal of the lamp so as to
protect them from accidental touch.
To enable the lamp to be used for various, purposes and especially to adapt it
or bedroom use I mount it upon a support of novel construction which may be

page_text: stood upon a dressing or other table, and be moved about as required, or may be
firmly suspended against a wall or attached to a ledge or other surface such for
instance as the top of a looking glass or the ledge of a dado, so that one lamp may
be used in a large number of places and positions, and its general utility thereby
greatly increased. This novel electric lamp-stand or support is illustrated in
Figuras 5.
The current of electricity is conveyed to the lamp A by a flexible cord or cords C
containing the flow and return wires suitably insulated, and in order to prevent
entanglement of the said cord and the inconvenience arising therefrom, I form the
lamp support with a hollow stem D adapted to receive the said cord and
terminating in a tripod stand or base D' of a form similar to that shown in
Figures 5, or of such other form as will support the flexible cord or a part thereof
when coiled around it, and prevent its trailing about the room or table, spring
clips or cleats such as E being fixed to the lamp holder to facilitate this. The
hollow stem of the lamp support may be made telescopic as shown in Figs 5,
spring clips or hand catches or equivalent devices being provided for retaining the
telescopic parts in position when drawn out.-I preferably, however, use a friction
collar or stuffing of rubber within the lower tube for the purpose of retaining the
telescopic tubes in their set position, as will be well understood without a detail
illustration.
To enable my improved electric lamp holder to be steadily supported against a
wall or suspended without swaying from the upper edge or portion, say, of a
looking glass or dado and thereby to greatly increase its utility for general purposes
I attach to the hollow.stem D or form in-one. therewith a short-bracket--arm-F-
terminating above in a loop or eye f and below in a point or pin fl constituting a
hook, and I am thus enabled to suspend the lamp from a nail or hook against a
wall or similar surface, or upon the looking glass as in Figure 5ª or it may be a
picture frame, without swaying, and in any desired position. The base D' of the
lamp may also be provided with a loop or eye f and also with a point or pin f¹
constituting a hook, and the lamp holder can be thereby supported upon a nail in
a horizontal position either against a flat surface such as a wall as in Fig 10, by
using the loop or eye f, or upon a ledge or shelf' as in Fig: 5*, by using the hook f¹.
An electric lamp support constructed with a double tripod base, and intended
chietly for Drawing Room use is shewn in Figures 6. This lamp support it will be
Been is capable of standing in two positious on a horizontal surface as shewn in
Figures 7 & 8, and may be also supported against a wall or other vertical surface
in either of the positions shown in Figure 9.
This modification of the lamp support is particularly adapted for lighting the
music on pianos when placed in the position shown in Fig: 7 overhanging the
music.
It will be understood that in all these cases the stem of the lamp holder is tubular
or hollow for the reception of the conducting wire or wires and that each lamp holder
may be formed to carry two or more electric lamp-sockets and lamps.-For Library
use a telescopic lamp stand of the kind above described may be placed on a table
near a chair and give light to a reader, as shewn in Fig: 10.
In some cases I may find it convenient to fit the spreading bases of my telescopic
electric lamp stands with spring reels or hand winches after the manner described
in the Specification of my Patent dated thirty-first August One thousand eight
hundred and eighty-two, N° 4162 for the purpose of preventing the slack wire or
cord trailing on the floor; or they may be fitted with the hand winch arrangement
and handle, also described in the above named Specification; in which case the
stand and its lamp can be more conveniently carried about and moved by hand to
the spot where it is required and be there suspended.
The free end of the flexible cord leading from these improved lamp holders and
lamps I pass through a knob or plug G of vulcanite wood or other insulating
material see Figures 11, and secure the strands of the flow and return wires
respectively by means of binding screws to metallic projections g g attached to

page_text: opposite sides or parts of the stem of the knob or plug, which is slotted or drilled
centrally to receive the said wires.
The metallic projections g g are suitably insulated the one from the other and are
formed with slightly rounded extremities like those of a key, adapted to be
inserted in slots of corresponding form in a guard plate H see Figures 12 & 13,
and make contact with curved spring terminals h h fixed behind or beneath the
Faid guard plate when the knob G is turned to a certain position.-These
spring terminals are shown in Figures 13 & 14 and consist of curved pieces of
metal broad at one end to form a base or point of attachment, and tapering towards
the other to form a spring tongue.-The broad end is secured to the interior of the
socket by a screw or screws which also connect the ends of the branch flow or
return wires to their respective spring terminals. The tapering end of each spring
is bent back upon or towards its base, to accommodate a greater length of metal in
a small space, and terminates in a hook h¹ which enters a notch cut in
the guard plate of the socket or it may be in a ring of insulating material h³ as
shewn in Fig: 14. I thus obtain a durable spring of considerable elasticity and the
notches into which the hooked or plain ends of the springs enter or dip serve as
stops for the metallic keylike projections, and prevent end way strain being thrown
upon the spring terminals. To ensure better electrical contact with the key, the
ends of the spring terminals are preferably slit in two or more places. Fixed stops
hh are also placed in the path of the keylike projections g g to prevent the knob
or plug G being turned in the wrong direction and the wires being short circuited
The guard plate when screwed on or fixed in place may be caused to partly overlie
and nip the bases of the spring terminals, and a guide plate may be used (as in a
Lock) to direct the course of the key-like projections and prevent tampering with
the Springs.
When the Lamp is required for use it is merely necessary to insert the stem of
the knob or plug G with its key like projections in the orifice of the Box containing
the fixed terminals h h and give it a quarter turn, whereupon the current if flowing
will pass to the Lamp by the wires of the flexible cord.
To prevent the accidental displacement of the knob or plug G from the Box
containing the terminals h h, I use a locking plate X which is capable of being
[artly rotated by a projection x (shewn in Fig 15) This plate has a slot which
in one position coincides with the orifice in the box, and in its other or locking
position partially closes such orifice, and prevents the withdrawal of the knob or
plug G.
A knob or plug with metallic projections on its stem as abovo explained may be
used in conjunction with spring terminals of the kind above described as a switch
on a single line wire to make or break the electrical circuit, and in this case the
flexible cord will not be necessary and a short piece of lead wire of suitable resist-
ance may be used as a fusible bridge to connect the two metallic projections on the
stem of the plug, thereby combining the advantages and convenience of a safety
plug and an ordinary switch. This arrangement is shewn in Figure 16, in which
g¹ represents the piece of lead wire connecting the key like projections g g and
939 are the screws for holding it in place. Further description of the drawing
will be unnecessary.
The resistance of such a safety switch can be accurately determined by the
gauge of the wire and can be easily varied, while the lead wire when fused can be
instantly renewed. Screws are conveniently used but small spring clips may be
employed in lieu thereof to secure the short piece of lead wire rapidly in place.
This simple and efficient removable safety switch it is obvious can be used for
-electric installations generally; and it may be combined if desirable with the flow
or the return wire in a flexible cord from a bracket or support for electric lamps.
When spring connections similar to those above described are used to attach
Electric lamps to their sockets the parts will require some slight modification as
shewn in Figures 17 & 18
The spring terminals may remain substantially the same as those above

page_text: described but the pins or key-like metallic projections g g will be necessarily
slighter and more delicate in construction, and the manner of fixing the said pins
or projections in the Lamp requires care in order to secure sufficient strength and
prevent undue strain being thrown upon the glass of the Lamp.
The pins I form of any suitable metal wire and I flatten thein out to about one
quarter of an inch broad for a greater portion of their length so that when
embedded in the glass, or in a filling of Plaster of Paris or other cement within
the neck or base of the lamp, A, they may be very firmly gripped by the Lamp,
and will stand considerable force without risk of breaking the glass. The extreme
end of each piece of wire may be either round or flattened, and is bent at right
angles to form the key-like projections g g adapted to engage with the curved
springs within the socket (see Figures 17 and 18) These pins thus serve as
electrical circuit connectors and as locking devices for retaining the lamp in its
socket at the same time
Loops or eyes of platinum wire, if of sufficient length and at a suitable distance
apart could be made to serve the purpose of my key-like projections in an electric
lamp by bending them at right angles or nearly so to their stems as indicated in
the Pian view Fig: 17%.
The lamp itself may be supported by a spiral spring holder as in the "Swan
Lamp" but I prefer to weld or solder the lust coil of the spring into a complete
circle or ring fitting within a groove in the socket. Should the lamp be lop sided
-or malformed its defects can be concealed or corrected by-slightly tilting -it-one
way or the other. This can be easily done by giving the spring support or socket
an-axial-motion. I make.however.no. claim.to.this improvement in detail.
To provide for the disconnection of the lamp socket from the end of its hollow
bracket or support without injury to the wires by twisting I connect the lamp
socket which is of wood or other insulating material with the end of the bracket
by squaring the one and making an aperture of corresponding shape in the other,
the low and return wires being secured to opposite sides of this socket.
The guard plate or rover is screwed on to the top of the socket, and hence when
the lamp is detached the guard. plate or cover can be freely unscrowed and access
to the wires be had without twisting them or injuring them at all.
The wooden soket may be pinned to the Equare end of the bracket by a screw
passed through both, and can readily be slipped off by slackening the wires
within it
I preferably however connect the guard plate with the end of the bracket by a
threaded collar engaging with the latter and drawing down both the guard plate
and socket upon the bracket, and this arrangement is shewn in Figs 3, & 18.
To enable a lamp fitted with loops of wire to be readily attached to or detached
from the pins or hooks within a socket, and to maintain the contact even under
severe vibrations and jerks, I use pins of wire partially flattened out as above
explained to serve as springs, and also to afford an efficient base for the
attachment to them of the wires and for securing them to the socket as shewn in
Figs. 19.
These pins I arrange parallel but out of line, and with their unflattened
hooked or bent ends extending in opposite directions as shewn in plan view
Fig: 19
The loops of wire in the lamp I also arrange parallel but out of line see Figs 20
and y engaging the hooked or bent ends of the spring terminals with the loops
on the lamp I obtain a tight contact This Contact I maintain by means of small
nuts which I screw on the threaded ends of the spring terminals when the loops
are in place thereon. The socket I is formed with a division or tongue i between
the pins of wire, and thus these pins have additional stiffness in a lateral direction
imparted to them.
Having now set forth the nature of my Improvements in the construction of
Incandescent lamps and in supports and electrical fittings to be used therewith
which improvements are in part applicable to electric lighting generally," and

page_text: having explained in what manner the same may be carried into practical effect, 1
wish it to he understood that I claim
:
First The means described with reference to Figures 1 to 4 of the accom-
panying drawings, for facilitating the attachment of Incandescent lamps to their
sockets and consisting essentially of a pair of metallic plates or pieces cc fitted
within a tubular extension a of the lamp A, and electrically connected with the
carbon filainent therein, and a pair of suitably insulated metal tongues such as d d
mounted on or within a socket on the bracket or other lamp support, the said metal
tongues being held distended by a spring such as d' or its equivalent, and adapted
to enter the said tubular extension when the Lamp is in one position and to make
contact and engage with the plates or pieces therein when the Lamp is partially
rotated, substantially as set forth.
Secondly, The improved movable stand or support for electric lamps described
with reference to Figs 5 of the drawings consisting of a stem for the reception of
a flexible cord or cords containing the flow and return wires a spreading or tripod
base so shaped as to retain the cord when coiled around it and means such as fƒ'
adapted to temporarily suspend the said Lamp-stand in place against flat surfaces
such as walls, or to attach it to the tops of ledges, looking glasses, dados aud like
surfaces in a variety of positions, as set forth.
Thirdly The combination with a hollow stem or standard D for one or more
electric lamp sockets and lamps, and a spreading base D¹ adapted to support the
said stem on level surfaces and prevent its swaying when suspended against a wall
or upon a picture frame, dado or the like, of incans such as ff adapted to
engage either with a nail in a wall or to hitch or hook the lamp to or
upon the tops of picture frames, doors, looking glasses, dados and the like as
set forth.
Fourthly My improved telescopic stand or support for one or more electric
lamps consisting of a spreading base supporting a hollow stem made of two or
more sections sliding the one within the other, and through which a lexible cord
or cords containing both the flow and return wires can pass freely in unbroken
connection from the lamp socket or suckets to and beyond the base as set forth.
Fitthly A movable stand or support for one or more electric lamp sockets and
lamps having a hollow stem formed in two or more sections adapted to slide the
one within the other and thereby to adjust the position of the Lamp, a spreading
base comprising three or more feet, means for retaining the telescopic portions of
the stem in their set position, and means such as ffi forming part of the said
stand, for supporting it in various positions, as described.
Sixthly The modification of my improved movable lamp described with reference
to Figs 6, 7, 8, and 9, of the drawings, and consisting in addition to the tripod or
spreading base from which rises the hollow stem for the reception of the flexible
cord, of an extra foot or branch and loops or eyes formed in or attached to the said
base and extra foot for the purpose of enabling the lamp to be securely stood or
suspended in a variety of positions whero its utility is greatly enhanced
substantially as set forth.
Seventhly The improved detachable switch coupling described with reference to
Figures 11 to 15 of the drawings, for rapidly bringing into electric connection with
a pair of fixed spring terminals the flow and return wires within a flexible cord or
cords, the said switch coupling consisting essentially of a pair of springs, their ends
dipping into notches which prevent end way strain upon the springs when the
current is switched on, and a knob or plug fitted with key-like projections adapted
to enter a slotted face plate, and make efficient electric contact when turned in one
direction only with the terminal springs behind or beneath the said face plate in
the manner set forth.
Eighthly In a switch coupling for electrical purposes the combination with a
detachable plug such as G provided with insulated key-like projections adapted to
enter a slotted guard plate, of a pair of spring terminals h h each consisting of a
strip or strips of metal bent back upon or towards a base in electric connection

page_text: with a line wire, notches into which the ends of the springs dip and which prevent
endway strain upon the said springs, and a guide plate or stops for ensuring the
key plug being turned in the right direction substantially as set forth.
Ninthly The combination with a pair of insulated spring terminals such as h h
secured behind a face plate and electrically connected with one of the line wires,
and a knob or plug such as G provided with insulated key-like projections g g
adapted to enter a slot in the face plate and make contact with the said spring.
terminals when turned, of a short piece of lead wire connecting the two key-like
projections as shown in Fig 16, the whole constituting an efficient electric switch
applicable to electric lighting generally, and possessing the advantages of a simple,
exact and easily renewable safety fuse as set forth
Tenthly The switch attachment for electric lamps described with reference to
Figures 17 & 18 of the drawings and comprising a pair of spring terminals
constructed and arranged within a socket in combination with notches h³ sub-
stantially as described with reference to Figure 14, and adapted to engage with
projecting metal strips or wires forming part of the electric lainp A when the said
lamp is partially rotated within the said socket..
Eleventhly The novel arrangement of spring tongues and eyes described
with reference to Figures 19 & 20 of the drawings for securely uniting electric
Incandescent lamps with their sockets and ensuring efficient electrical contact
even under considerable vibration.
Twelfthly. The means described with reference to Figures 3, & 18,_of_the_
Drawings for facilitating the disconnection of the lamp socket from its supporting
bracket without twisting the wires.
In witness whereof I the said Thomas Tayler Smith have hereunto set my
hand and seal this eighth day of February in the year of our Lord One thousand
eight hundred and eighty four.
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