Improvements in connection with Incandescent Electric Lamps and their Holders and Fittings.
Year: 1895

page_text: Date of Appl.cation, 26th Aug., 1895
Complete Specification Left, 26th June, 1896-Accepted, 1st Aug.,
1896
PROVISIONAL
SPECIFICATION.
Improvements in connection with Incandescent Electric Lamps and
their Holders and Fittings.
I, JAMES YATE JOHNSON, of 47 Lincoln's Inn Fields, in the County of London,
Gentleman, do hereby declare the nature of this invention (which has been
communicated to me from abroad by Alfred Swan, of No. 318 East 123rd Street,
New York City, United States of America, Electrical Engineer,) to be as
follows:-
This invention relates to improvements in connection with incandescent electric
lamps and especially to the bases or caps and holders or sockets and similar fittings
thereof.
Instead of making the bases or caps (I will refer to them as caps) of incandescent
electric lamps of metal as heretofore, they are according to this invention made of
porcelain or like material (I will refer to it as porcelain) by moulding them in
form to suit the particular style of lamps and sockets with which they are to be
used.
The cap is made cup-shaped preferably with a flat bottom and is provided with
apertures recesses and other necessary details for the metal connections for
conducting the electric current. The said cap can be fitted to the neck of the
lamp and secured thereto by means of cement in the ordinary way.
The following are some of the forms which the caps constructed according to
this invention may take.
The cap formed of porcelain or like material according to the first modification
has a disc or bottom in which are two diametrically opposite circular apertures
bevelled or chamfered on their under edges or lips. These apertures are for the
reception of the metal contacts which consist of short tubular pieces of thin metal
one end of each being closed (like a gun cap) and stamped up or formed so as to
leave a slight rim or head. Each tubular picce when placed in its aperture in the
cap is supported by the said rim or head with the open end extending somewhat
beyond the porcelain and the said tubular piece is securely fastened in position by
burnishing, or laying over its projecting edge against the bevelled or chamfered
edge of the aperture.
The heads or rims of these contact pieces may be flush with the porcelain by
recessing the porcelain to the extent of the thickness of the said heads or rims or
they may be raised above the face of the porcelain to suit the form of contact
in the socket to which they are to be applied as hereinafter more particularly
described.
This form of cap is intended for a bayonet-joint style of socket and is provided
with studs or pins for engagement with slots in the socket tube to support the lamp
therein.
These studs or pins may either be nipples or projections moulded on the body of
the cap, or a hole passing through the thickness of the disc constituting the bottom
of the cap may be moulded or formed in the porcelain and a wire or pin of corre-
sponding size be fitted therein, the projecting ends of which wire or pin will furnish
the required projections.
Or the cap of porcelain according to a second modification may have a central
recess in which is fitted a threaded metal bushing to couple with a corresponding

page_text: thread on a metal plug or pin in the base of the socket in which it is to be inserted
so making one of the electrical connections with the lamp the other connection
being made by a flanged ring of thin sheet metal fitting over a shoulder formed on
the outer circumference of the said cap and making contact against a spring within
the lamp socket.
Or the cap of porcelain according to a third modification may have on its
external face and in the centre thereof a metal plug, or nipple, to which one of the
lamp wires is attached and which engages with a tubular spring in the lamp socket
and so forms one of the electrical connections therewith. A hollow bead of thin
metal, having a flange on its underside, is attached to the neck of the lamp by
springing it into a groove formed on the latter the other wire of the lamp being
attached to this metal bead and the porcelain cap as above described may be affixed
to the lamp neck in the usual way its lower edge resting on a shoulder within the
aforesaid metal bead.
Or the cap of porcelain according to a fourth modification may have a thread on
its outer circumference to engage with a corresponding thread formed in the shell
or tube of the lamp socket or a spring or lining therein electrical connection
between the two being effected by sheathing the uppermost thread on the said cap
with thin metal and connecting therewith one of the wires of the lamp.
The other metallic connection is furnished by means of a stud or button on the
face of the cap and in the centre thereof-this contact being made of thin metal-
formed similarly to and fastened in place as is that for the face contacts as described
with reference to the cap first described.
The inner surfaces of these porcelain caps should be roughened so as to afford a
good grip for the cement by which they are attached to the lamps.
The wires connecting the lamps with the contact pieces in the caps may either
pass through holes in the said contact pieces and be soldered thereto in the ordinary
way or the contact pieces may have short lengths of wire attached to their inner
'surfaces and the lamp wires be connected by twisting with these when fixing
the cap.
The following are forms of holders or sockets (I will refer to them as sockets)
respectively adopted to the caps hereinbefore described.
The socket for the first modification of cap consists of a block or base piece of
porcelain in which are formed two circular receptacles or pockets diametrically
opposite each other and of a diameter and a depth requisite to receive and cover the
metal terminal pieces to be used therein.
This porcelain block or base is provided near its upper end with a projecting
rim or hand of slight width constituting a " shoulder."
Lateral circular holes are formed immediately beneath this shoulder which holes
extend nearly, but not quite, through the fuil thickness or diameter of the porcelain
and are intended for the reception of screws by which to fasten in place the afore-
said terminal pieces and also for screws with which to make contact with the
conducting wires. They may be both on the same face of the porcelain piece or
they may be on opposite faces thereof.
The terminal pieces for the socket (bayonet joint style) may consist of a round
tubular case of thin metal of less diameter near its lower extremity so as to there
form a shoulder.
A buffer works snugly within the reduced portion of this case and is headed at
one end to abut against a shoulder within the case. A spiral spring acts on the
head of the buffer when under pressure the said spring filling the case to within
say about a quarter of an inch of its upper edge and in this portion of the tubular
case a solid block or plug is tightly fitted having a hole in its centre for the
passage of the bared conducting wire and through it laterally is a tapped hole for a
screw by which to clamp or pinch upon the said wire.
This form of terminal is intended to be introduced from above into its pocket in
the porcelain piece-the lower end of the hole in the latter being of less diameter
t correspond with the tubular case, the shoulder of the latter resting upon a

page_text: corresponding shoulder in the porcelain. An elongation of the smaller end of the
case projects beyond the porcelain and is burnished or laid over against the face of
the porcelain and so securely fastens the case in place--the apertures in the
porcelain being preferably bevelled on their lower edges to facilitate this operation.
With this form of terminal the apertures in the porcelain for the reception of
screws (as herein before described) may extend right through the face and upper
end of the porcelain piece that is to say the apertures are such as can in moulding
be formed from above.
In a modified form of terminal the tubular case of metal is dispensed with and
merely the block through which pass the screws as previously described is
employed the spiral spring being fastened thereto at one of its ends and having
attached as a buffer to its opposite end a similar block but without holes.
In this form the blocks at each end of the spiral spring as also the spiral spring
itself are of such size as to snugly fit and work within the pocket provided for them.
in the porcelain piece.
This terminal in its complete form is inserted in place from below and is caused
to abut against a shoulder or stop in the porcelain and it is fastened in place by a
headless screw pin-of which part is in the head piece or block aforesaid and part
in the hole in the porcelain immediately opposite.
The wiring and screw clamping may be the same as before described.
Instead of the solid buffer the spiral spring may have at one end a close and
tapering formation and so itself do duty directly as a contact piece-but the solid
buffer is preferable.
The two forms of contact described are for that form of lamp cap in which
the contact studs or metals are flush with the surface of said cap.
For that form of lamp cap in which the contact studs project above the
porcelain the following form of contact may be employed viz.: A metal block
holed for the wire and terminal screw as hereinbefore described fits into the
pocket of the porcelain piece, but is of greater depth or length so that it will
project say fully one sixteenth of an inch beyond the face of the porcelain
piece.
To a pin formed on the projecting end of this metal block is rivetted a plate
spring of hard drawn metal-preferably phosphor bronze.
This spring is of segmental shape bent upwards towards its free end and of such
length that a pair of springs when adjusted concentrically upon the porcelain form
nearly a complete circle which the projecting studs on the face of the lamp cap can
never escape when operating within the socket.
The other accessories which complete the construction of the socket are three
pieces preferably of stamped metal viz. :
1st. A tubular piece having bayonet slots at one end for the lamp and at the
other end a slightly projecting horizontal flange or lip and an upright tongue-the
former to impinge against the hereinbefore described shoulder on the porcelain
and the latter to lock into an indent formed in the said shoulder-so that the
bayonet slots may not vary their position in relation to the terminal contacts.
2nd. A ring or band hereinafter termed the "tightening ring
"
a part of which
is screw threaded and within which there is a recess or shoulder immediately below
the said threaded portion.
3rd. A covering piece or cap with nozzle in the centre thereof for attachment to
an electrolier or the like and having a flange or rim fitting over the porcelain
piece and resting upon the shoulder thereof.
The flange or rim of this cover is screw threaded to correspond with the thread
on the tightening ring and it projects slightly beyond the shoulder of the porcelain
piece to allow it to engage with the said ring.
As the tightening ring is screwed up its shoulder draws against the flange of
the slotted tube which in its turn is brought against the porcelain shoulder and
thus the whole combination is screwed rigidly and firmly together and the socket
is complete.

page_text: To adapt the socket for use in damp and exposed situations and also to further
simplify its construction, the slotted metal tube may be dispensed with. In which
case I make the entire body of the socket of porcelain-the bayonet joint groovings
for the lamp being on the inner face of the wall forming the tubular portion of
the socket.
This of course involves some increase in the external diameter of the body of
the socket and a corresponding enlargement of the metal covering piece and
tightening ring but in all other respects the socket remains the same as hereinbefore
described.
As the preceding details apply in many particulars equally to the three types
of socket yet to be described it must be understood that only their points of
difference in regard to their construction-will. be dealt with in what follows
respecting those three types.
The type of socket is suitable for the second modification of lamp cap herein-
before described and the terminal contacts for this socket required by the form of
lamp cap are a projecting threaded plug centrally situated in a porcelain base piece
and a circular shaped plate spring attached to the same piece-near its edge and
following its circumference-the former to engage with the recessed threaded
bushing in the lamp cap and the latter to make contact with the metal ring
surrounding the same.
A prolongation of the central plug enters and fills the central aperture or
pocket in the porcelain base. This prolonged part being holed for the wire and
screws similarly to and for same purpose as that herein before described.
The plate spring is nearly a complete circle and being fixed at its centre to its
bed it has two arms-thus its pressure upon the lamp cap is equalized and the
lamp is thereby kept firmly in its place.
This form of socket is peculiarly suited for embodiment in porcelain in
complete form, fulfilling the three important conditions of safety, simplicity and
effectiveness.
The type of socket suitable for the lamp cap herein before described under the
third modification is provided with terminal contacts consisting of a tubular spring
situated centrally in a porcelain base piece and a surrounding slotted shell of a
diameter equal to the diameter of the lamp cap.
The former makes contact with the plug or nipple projecting from the face of
the lamp cap; while the latter, by means of a hollow bead or groove formed from
within and on its under edge, makes connection with the metal bead on the lamp
neck, to which one of the wires of the lamp is attached-as hereinbefore
described.
The slotted shell in the ordinary form of socket of this type-is drawn stamped
and trimmed into shape by numerous operations. This inconvenient and wasteful
process is, by this invention, avoided by using flat strips of metal of the required
size and cutting out and forming by stamps and dies the required slots and indents.
Circular form can be given the shell by means of a mandril of the required
diameter and it is fastened in place on the neck of porcelain piece by screws at
opposite sides. One of these screws enters the metal block in the porcelain into
which passes one of the conducting wires-so making electrical connection
therewith whilst the other screw goes through the band of the shell on the
opposite side and entering a solid metal stud, placed within the porcelain at this
point, serves to tighten the shell firmly in its place on the neck of the porcelain
base piece.
The central tubular spring is attached to a binding post block similar to
that described for the screw plug of the socket of lamp cap of the second
modification.
The terminal contacts for a socket for the type of lamp cap of the fourth
modification consists of a flat spring to make contact with a central button or stud
on the face of the lamp cap and a metal screwed shell by means of which to make
electrical connection with the metallic sheathing on the thread of the said cap.

page_text: This screw shell may be such as is now used with this type of socket and be
fastened through its flange at the bottom by screws entering the metal blocks in
the porcelain piece-or the band of the shell may be vertical and have indents
therein to fit into corresponding indents in the porcelain and be fastened thereto
in the manner described for the slotted shell of the type of socket for the cap of
the third modification-or it may, in the case of a key socket, be connected with
the outer metal shell and be insulated therefrom by some non-conducting
substance.
In either case the same form of binding post block in pockets of porcelain
connects with these terminals.
The metal screw shell may if desired be wholly omitted and porcelain be
substituted.
In this case a groove or recess is provided extending lengthwise or vertically
across threads formed in the wall constituting the socket to receive a spring which
has at its free end a lip corresponding with the thread in the porcelain so that
when the lamp is inserted the lip on the spring engages with the thread in the
lamp cap and as the cap is screwed home the spring acts thereon and so holds the
lamp firmly in its place. Or a lining or sheathing of thin metal may be impressed
or rolled into grooves or threads of the porcelain-wholly or partially covering
the interior surface of lamp recess and contact be made between the said lining
and one of the terminals in the porcelain base block.
The sockets herein described may be used with lamps capped as now or old
style sockets may be used with these caps on the lamps made according to this
invention.
The three last preceding forms or types of socket not requiring any fixed
relationship between the outer case or shell and the terminals within them (as is
required in the bayonet joint form) enable the shell and tightening ring to be
combined in one and the same piece.
Although sockets of the keyless type only have been described a key arrangement
for each can readily be provided on the principle of a ratchet or cam working upon
a shaft passing through the side of the porcelain piece the said cam having a
spring acting upon one of its faces while on the other or opposite face it makes
contact directly upon a horizontal rim or flange forming a part of the screwed
shell and the slotted shell respectively in the case of the last two types of socket
and in the case of the second type a cam or rachet acting in each case directly upon
one of the contacts of the lamp cap can be employed.
The direct action of a cam ratchet or circuit controller upon the flange or
analogous part of the shell into which the lamp fits and is held constitutes a part of
this invention.
The only difference in external appearance of this key form of socket is its
slightly increased length and in some trifling modifications of the outer metal shell
and nozzle piece to suit the key arrangement and the two parts may be connected
together by screws or other suitable fastenings instead of the parts themselves
being screw threaded as in the case of the keyless form herein before described.
Sockets made wholly of porcelain can be readily fixed in position on a wall or
partition or the like by means of a ring of light metal with a flange through
which to screw it to the wall partition or the like, a shoulder on the ring
engaging with the shoulder on the porcelain socket or the shoulder on the
porcelain socket can be made sufficiently large to have holes therein for the
fastening down screws.
In some cases for instance on damp and exposed situations it may be advisable
to coat the external metal parts with some water-proof preparation such as rubber
or japan or the like this serving also the purpose of insulating the parts electrically
where desired.
A lamp shade or globe or a gallery therefor may be secured to the socket by
clamping a rim or flange formed on the said shade globe or gallery between the
tightening ring hereinbefore referred to and another ring screwed onto the

page_text: externally threaded tube or case, or the lamp shade carrier may be formed in one
with, or be fixed to, the tightening ring, or its equivalent.
Dated this 26th day of August 1895.
JOHNSONS & WILLCOX,
47 Lincoln's Inn Fields, London, W.C., Agents.
Improvements in connection with Incandescent Electric Lamps and
their Holders and Fittings.
I, JAMES YATE JOHNSON of 47 Lincoln's Inn Fields in the County of
London, Gentleman, do hereby declare the nature of this invention (which has
been communicated to me from abroad by Alfred Swan of No. 318 East
123rd Street, New York City, United States of America, Electrical Engineer,)
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 improvements in connection with incandescent electric
lamps and especially to the bases or caps and holders or sockets and similar fittings
thereof.
Instead of making the bases or caps (I will refer to them as caps) of incandescent
electric lamps of metal, as heretofore, they are according to this invention, made
of porcelain or like material (1 will refer to it as porcelain) by moulding them
in form to suit the particular style of lamps and sockets with which they are to
be used.
The cap is made cup shaped preferably with a flat bottom and is provided with
apertures recesses and other necessary details for the metal connections for
conducting the electric current. The said cap can be fitted to the neck of
the lamp and secured thereto by means of cement in the ordinary way, or by screws
as hereinafter described.
I will describe the invention with reference to the accompanying drawings.
Referring to Figure 1; the cap A, of porcelain, or like material, has formed in
the closed end, or bottom, a, two preferably circular apertures a bevelled or
chamfered on their inner edges or lips. These apertures are for the reception of
metal contacts b which consist of tubular pieces of thin sheet metal, one end of
each being closed (like a gun cap) and stamped up, or formed with a head b³,
having a slight rim or shoulder by which the piece b when placed in its aperture
in the cap is supported. The open end of each of the tubular pieces extends
somewhat beyond the inner edge of the aperture a in the porcelain, and the said
tubular piece is securely fastened in position by burnishing or laying this pro-
jecting edge over against the said bevelled, or chamfered, edge as shewn at 6³.
The heads, or rims, 3, of these contact pieces may be raised above the porcelain
as shewn in Figure 1, or, by recessing the porcelain to the extent of the thickness
of the said heads, or rims, they may be flush with the face of the porcelain as
shewn in Figure 2, according to the form of contact in the socket to which they
are to be applied as hereinafter more particularly described.
This form of cap is intended for a bayonet joint style of socket, and is provided
with studs, or pins, c, for engagement with slots in the socket tube to support the
lamp therein.
The studs, or pins, c may either be nipples, or projections, moulded on the body
of the cap, as shown in Figure 1, or a hole, passing transversely through the closed
end or bottom a of the cap may be moulded, or formed, in the porcelain, and a
wire or pir, c, of corresponding size be fitted therein, the projecting ends of which
wire, or pin, will furnish the required projections.

page_text: According to a second modification shewn in Fig. 3 the cap A of porcelain has
a central recess 6 in which is fitted a threaded metal bushing d to couple with a
corresponding thread on a metal plug, or pin, in the base of the socket in which
the said cap is to be inserted, so making one of the electrical connections with the
lamp the other connection being made by a flanged ring of thin sheet metal
fitting over a shoulder formed on the outer circumference of the said cap A and
making contact against a spring within the lamp socket as hereinafter described.
The lamp is shewn as being connected to the cap A by means of screws a
passing through slots or openings in the porcelain cap and screwing into a ring a*
secured by cement in a recess formed in the neck of the lamp.
According to a third modification as shewn in Fig. 4, the cap A of porcelain has
on the exterior and in the centre of the closed end, or bottom a metal plug or
metal sheathed projection d to which one of the lamp wires is attached and which
engages with, or bears against a spring in the lamp socket, and so forms one of
the electrical connections therewith, the other electrical connection between the
lamp and the cap A being made by a thin metal cover, or sheathing, on a bead f
formed on the porcelain cap A around the lower, or open, end thereof the other of
the wires of the lamp being attached to the said sheathing which in its turn makes
electrical connection with the socket when the lamp is inserted therein.
According to a fourth modification as shewn in Figure 5 the cap A of porcelain
has a screw thread on its outer circumference, to engage with a corresponding
thread, formed in the shell, or tube of the lamp socket, electrical connection being
effected between the cap A and the socket by a metallic sheathing 2 on the thread
of the said cap A in contact with a spring, or with a metal lining in the socket, to
which spring, or lining, one of the conducting wires is attached; and connecting
one of the wires of the lamp to the metal sheathing on the cap, the other metallic
connection being furnished by means of a metallic stud, or button, d, on the exterior
face of the bottoin or closed end of the cap to which the other wire of the lamp is
connected. This stud, or button, when the cap is inserted in the socket makes
contact with a piece in the socket to which the other conducting wire is
connected.
The wires connecting the lamps with the contact pieces in the cap may pass
through holes in the said contact pieces and be soldered thereto in the
ordinary way.
The following are forms of holders or sockets (I will refer to them as sockets)
adapted to the caps herein before described.
Sockets suitable for the cap illustrated in Figures 1 and 2 are shewn in sections
and plans in Figures 6 and 7 in which B represents a block, or base-piece, of
porcelain in which are formed two preferably circular receptacles, or pockets, g,
of a diameter and depth requisite to receive and cover the metal terminal pieces to
be used therein.
This porcelain block or base B is provided near its upper end with a projecting
rim or band of slight width constituting a "shoulder" for a purpose hereinafter
described.
Lateral circular holes i Figure 7 are formed immediately beneath this shoulder h
which holes extend nearly, but not quite, through the full thickness, or diameter,
of the porcelain base B and receive screws as shewn in Figure 6 by which to
fasten in place the aforesaid terminal pieces, and also for screws by which to
connect the conducting wires to the terminal pieces. The holes i may be both on
the same side of the porcelain block or they may be on opposite sides thereof as
shewn.
The terminal pieces shewn in Figure 6 consist each of a round tubular case / of
thin metal of less diameter near its lower extremity so as to there form a
shoulder 1.
A buffer m works snugly within this case the said buffer having a head at one
end to abut against the shoulder within the case 1. A spiral spring n acts on the
head of the buffer m when under pressure, the said spring filling the case to within,

page_text: say, about a quarter of an inch of its upper edge, and in this portion of the said
tubular case a solid block or plug o is tightly fitted. This plug has a hole P therein
for the reception of the bared conducting wire and extending laterally through the
plug is a tapped hole i for the screw by which to clamp or pinch upon the said
wire to hold it in position.
This form of terminal is intended to be introduced from above into its pocket g
in the porcelain base piece, or block, the lower end of which pocket is of less
diameter to correspond to the diameter of the lower end of the tubular case,
the shoulder 2 of which rests upon a corresponding shoulder formed in the
pocket g. The smaller end of the case is sufficiently long to project beyond
the porcelain base, and the said projecting end is burnished or laid over against
the face of the porcelain, so as to securely fasten the case in place, the lower edge
of the apertures or pockets / in the porcelain being preferably bevelled to facilitate
this operation.
With this form of terminal the apertures i in the porcelain for the reception of
screws may extend right through the upper end, or face, of the porcelain base
piece or block B, that is to say, the apertures are such as can, in moulding the
block, be formed from above.
In a modified form of terminal shewn in Figure 7 the tubular case of metal
herein before described is dispensed with. The block or plug o through which pass
the screws k and ² as previously described is connected to one end of the spiral
spring n the other end of the said spring being attached to a block m constituting
a buffer. The blocks o and m, and also the spiral spring n when connected as
described are such as to snugly fit and work within the pocket 7 provided for them
in the porcelain piece or base B.
This terminal in its complete form is inserted in place from below and is
caused to abut against a shoulder or step in the pocket g, and it is fastened
in place by the headless screw pin k, of which part is in the block o, and part in
the porcelain.
The conducting wire can be connected to the terminal piece by the clamping
screw as before described. Instead of the solid block m the spiral spring
may have its outer end of a close and tapering formation as shewn in Figure 8,
and so itself act directly as a contact piece but the solid buffer is considered
preferable.
The forms of contact pieces described are suitable for that form of lamp cap, in
which the metal contact pieces, are flush with the surface of the cap as shewn in
Figure 2.
For that form of lamp cap in which the contact studs project above the
porcelain as shewn in Figure 1 the form of contact shewn in the socket
illustrated by Figure 9 is suitable. Each contact consists of a metal block o,
inserted in the pocket g, in the porcelain and holed for the reception of the
conducting wire and terminal screws as herein before described, but the said block,
is of greater depth than the pocket, so that it projects say fully one sixteenth of an
inch beyond the face of the porcelain base piece.
To the projecting ends of these metal blocks are rivetted plate springs t of
hard drawn metal (preferably phosphor-bronze) with their free ends bent as
shewn.
Each spring is of segmental shape as shewn in the underside view, and of such
length that a pair of springs when adjusted concentrically upon the porcelain
socket form so near a complete circle that the projecting studs b² of the lamp
cap A Figure 1 can never escape them when operating within the socket.
The other accessories required to complete the construction of the socket
suitable for the caps illustrated by Figures 1 and 2, are three pieces preferably
of stamped metal viz. : 1st. A tubular piece C, (Figures 6 and 7) having bayonet
slots at one end for the reception of the nipples or projections c on the cap of
the lamp and at the other end a slightly projecting horizontal flange or lip c
Figure 7, and an upright tongue, the flange or lip, to impinge against the herein-

page_text: before described shoulder h, on the porcelain base of the socket and the tongue to
engage in an indent et formed in the said shoulder, so that the bayonet slots c
may not vary their position in relation to the terminal contacts or buffers in the
pockets of the socket B. 2nd. A ring or band D, hereinafter termed the
"tightening ring" a part of which is screw threaded and within which ring
directly below the said threaded portion, there is a recess or shoulder d². 3rd. A
covering piece or cap E with a nozzle e in the centre for attachment to an
electrolier or the like, the said covering piece having a screw threaded flange
or rim fitting over the top of the porcelain base piece or block B, and resting
upon the shoulder h. The screw thread on the flange or rim of this cover,
corresponds with the thread d³ in the tightening ring D, and it projects slightly
beyond the shoulder h of the porcelain piece to allow it to engage with the said
ring.
As the tightening ring D, is screwed on to the rim of the cover, its shoulder
draws against the flange c³ of the slotted tube C, which in its turn is brought
against the porcelain shoulder h, and thus the parts are secured rigidly and firmly
together and the socket is complete.
Instead of securing the tube C to the base or block B, by means of the
tightening ring E as hereinbefore described, the said tube may be made shorter
as shewn in Figure 6 and fit on to a reduced portion of the base B, in which
reduced part indents care provided, into which the metal of the tube may be
punched, so as to securely hold it in position.
The better to adapt the socket for use in damp situations and also to make it
safer for use with lamps of high voltage the entire body of the socket is formed of
porcelain as shewn in Figure 10 and in the interior, angled grooves c³ are formed
for the reception of nipples or projections on the cap of the lamp. Or within the
hollow cylindrical part of the socket there is inserted (as shewn in Figure 11) a
band or ring C of metal with bayonet slots c² therein to receive the pins or studs
that project from the sides of the lamp cap. Two arms c6 at diametrically
opposite points on this ring, extend upwards within grooves formed in the interior
of porcelain socket and are fixed therein by means of screws e passing through
countersunk holes c' in the porcelain and screwing into nuts in the interior of the
socket.
This metal ring C provides for inequalities in the porcelain and ensures a smooth
and certain action between the lamp cap and the socket.
A lamp socket or holder suitable for the second modification of cap or base
herein before described is shewn combined with the said cap in Figure 3. The bed
or block B to which the electrical circuits are affixed and also the hollow
cylindrical portion which forms the receptacle for the cap of the lamp, are made
of porcelain thus the socket is so far one integral piece.
Two circular shaped vertical apertures or pockets g, are formed in the base B
(one in the centre and one near the circumference) and lateral piercings i cross
these vertical apertures.
Fitting into these apertures, are metal blocks or posts o, of a shape corre-
sponding to that of the apertures, each block having a vertical hole p through
it for the passage of a wire lead, and a transverse threaded hole for a threaded pin,
which holds the post in place, as well as for a binding screw ², with which to
tighten upon the wire, which passes through it. The pin and screw enter the
lateral piercings i.
When placed in position these blocks o abut against a shoulder r, formed in the
sockets g, or that the lateral holes in the porcelain, and in the metal posts
respectively are brought to the same level.
The central metal post o is prolonged and its lower end projects into the hollow
cylindrical portion of the socket. This prolonged end or nipple, is threaded to
engage with the thread of the shell d, within the recess in the face of the lamp cap
and so it makes electrical connection therewith. To the metal post o, occupying
the outer vertical recess in the porcelain bottom of the socket a sheet metal
B

page_text: spring m² is secured the said spring being preferably of ring form, and slightly
raised above the inner face of the base B. It constitutes the other contact of
the socket, and when the lamp is screwed home, and the metalf of its cap is pressed
against the said spring m2, the electric circuit is completed.
The vertical grooves or channels 9, on the outer face of the socket, at points
diametrically opposite, and stopped short a short distance from its under lip, are
for the attachment of a shade carrier.
The socket suitable for the lamp cap herein before described under the third
modification with reference to Figure 4, is shewn in that figure in combination
with the cap. It is provided with terminal contacts consisting of a spring n, in a
recess or pocket 9, situated centrally in the porcelain base piece B, and of a
surrounding slotted metal shell C, of a diameter corresponding to the diameter of
the lamp cap. The spring n is attached at its inner end to a post or block o, to
which one of the leads is connected as herein before described, whilst the other end
of the spring projects outside the pocket g, and makes contact with the plug or
stud d projecting from the face of the lamp cap, when inserted in the socket. The
other contact is made by means of a hollow bead or groove f³ formed within,
the lower edge of the metal shell C, which bead or groove makes connection with
the metal sheathing on the bead of the lamp cap A to which one of the wires
of the lamp is attached as hereinbefore described. The said metal shell C is
fastened in place on the neck of the porcelain socket B, by screws w, one of which
passes through the shell into the metal block o² in the porcelain socket to which
block the other conducting wire is attached, so making electrical connection
therewith, whilst the other screw passes through the band of the shell on the
opposite side, and enters a solid metal stud u² inserted within the porcelain at this
point.
A socket suitable for the type of lamp cap of the fourth modification described
with reference to Figure 5, is shewn in combination therewith in the said Figure 5
and consists of a cup-shaped socket made of porcelain, having secured to it a flat
spring or plate n to make contact with the central button or stud, d on the face
of the lamp cap A. The hollow cylindrical portion of this socket is screw-
threaded in the interior corresponding to the screw thread on the exterior of the
lamp cap A. A groove or recess v, extending lengthwise, across the threads in
the socket receives a spring ir, which has at its free end a lin w², corresponding to
the thread in the porcelain so that when the lamp cap is inserted the lip w
engages with the metal sheathing f³ on the thread in the lamp cap A, and as
the cap is screwed home, the spring wr, acts thereon and so holds the lamp
firmly in place. Or a lining or sheathing of thin metal may be impressed or
rolled into the screw thread of the porcelain socket so as to wholly, or partially,
cover the said thread, and thus contact be made between the said metal lining,
and one of the terminals in the porcelain lamp cap. Or a metal screwed
shell C shewn in Figure 12, may be provided to make electrical connection with
the metallic sheathing on the thread of the lamp cap. This screw shell may be
such as is now used with this type of socket and be fastened through its flange r
at the bottom by screws entering the metal blocks y, in the porcelain piece B, or
the shell may have indents therein to fit into corresponding indents in the porcelain
and be fastened thereto in the manner described for the slotted shell of the type of
socket for the cap of the third modification, or it may be connected with an outer
metal shell C2, and be insulated therefrom by some non-conducting substance, such
for instance as the screw collar C³ as shewn in Figure 12.
The sockets herein before described may be used with lamps capped in the
ordinary manner and the lamp caps constructed as hereinbefore described may be
used with lamp sockets now in use.
As the three last described forms of socket do not require any fixed relation-
ship between the outer case or shell and the terminals within them, the shell
and tightening ring can be combined in one and the same piece.
Although sockets of the keyless type only have been described a key (or

page_text: switch) arrangement can readily be provided for each as shewn for example in
Figure 13 in which is shewn a cam F on a shaft F passing through the side
of the porcelain socket B, and having its bearing in a U shaped metal bridge
piece F secured to the socket B. On the said cam F bears a spring m³, which
is rivetted to a metal post o to which one of the conducting wires is attached
the said spring being bent upwards into a trough or recess formed in the base B.
The cam F may be of rectangular form with the corners rounded and with an
elongated slot (to provide for irregularities of construction and ensure good
electrical contact) through which slot the shaft F2 passes and through another
opening in the cam F at right angles to the shaft passes a steel or other metal pin
the ends of which project slightly. When the key shaft is turned it gives motion
to the cam F, and when therefore the lamp cap is screwed home and the key is
turned so as to bring the cam into the upright position shewn, the cam is in contact
at its lower end, with the annular metal rim f on the lamp base, while its upper end
presses the spring m² and so completes the electrical circuit.
When the key is turned to open the circuit, it first has a short motion independent
of the cam, as soon as the cam has been turned sufficiently to carry its diagonally
opposite corners beyond the centre, the spring acts upon it and throws it quickly
out of contact, with itself and with the metal rim on the cap of the lamp. This
quick movement is promoted by the lost motion provided between the cam and the
shaft. By having the slot within the cam block itself, the arms of the bridging
piece can be brought near together, thus compacting the mechanism, while at the
same time the central part of the socket block is left free for the attachment of
any form of a centre contact.
Sockets made wholly of porcelain can be readily fixed in position on a wall or
partition, or the like by means of a ring of light metal H Figure 14 with a flange H*
through which to screw it to the wall partition or the like, a shoulder H³ on the
ring engaging with the shoulder h, on the porcelain socket, or the shoulder h on
the porcelain socket can be made sufficiently large to have holes formed therein
as shewn in Figure 15, for the fastening screws. The shoulder on the socket and
the screws being covered by a cap H³ secured to the socket by a projection
engaging the lower edge of the cap as shewn.
In some cases for instance in damp and exposed situations it may be advisable
to coat the external metal parts with some waterproof preparation, such as japan
or the like this serving also the purpose of insulating the parts electrically where
desired.
A lamp shade or globe, or a gallery therefor may be secured to the socket by
clamping a rim or flange, formed on the said shade globe or gallery, between the
tightening ring D hereinbefore referred to and another ring screwed on to the tube
or case, or the lamp shade or globe carrier may be formed in one with, or be fixed
to the tightening ring or its equivalent.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed I declare that what I
claim is :-
1. Incandescent electric lamp bases or caps made of porcelain or the like, in the
manner, substantially as hereinbefore described.
2. Cup shaped bases or caps for incandescent electric lamps, made of porcelain
or the like, and having in the bottom or closed end two apertures fitted with metal
connections for the wires of the lamp, the said connections consisting each of a
short tube having one end closed and provided with a rim or flange to rest on one
edge of the aperture in the base or cap, the open end of the said tube being laid or
burnished over the other edge of the said aperture substantially as herein before
described and shewn in Figures 1 and 2 of the accompanying drawings.
3. Cup shaped bases or caps for incandescent electric lamps, made of porcelain
or the like, by moulding them in the form required and with studs or projections,
or with holes formed transversely through the closed end thereof, to receive pins

page_text: or wires, to form studs or projections, to engage with bayonet slots in the sockets
with which the bases or caps are to be used, substantially as hereinbefore described
and illustrated in Figures 1 and 2 of the accompanying drawings.
4. An incandescent electric lamp base or cap of cup form made of insulating
material with a central cylindrical cavity in combination with a cylindrical metallic
shell or lining fitting into the said cavity and held in place by flanges on its ends
bearing against shoulders on the insulating cap substantially as herein before described
and illustrated in Figure 3 of the accompanying drawings.
5. An incandescent electric lamp base or cap of cup form made of insulating
material with a central cavity in it fitted with a metallic bushing or lining in
combination with a metallic ring on the exterior of the cap, the conductors of
the lamp being respectively connected to the metallic bushing and the ring sub-
stantially as hereinbefore described and illustrated in Figure 3 of the accompanying
drawings.
6. An incandescent electric lamp base or cap, made of insulating material and
having a metal stud or button to which one of the lamp wires is attached and which,
when in position in the lamp socket or holder, bears against a spring in the said
socket or holder and so forms one of the electrical connections, the other electrical
connection being formed by a bead on the porcelain cap or base sheathed with metal to
which the other wire of the lamp is attached the said metal sheathed bead making
contact with the metal in connection with the socket or holder, when the lamp cap
is inserted therein substantially as hereinbefore described and illustrated in Figure 4
of the accompanying drawings.
7. An incandescent electric lamp base or cap made of insulating material and
having on its circumference a screw thread coated in whole or in part with metal
and at its base a metal plug, or sheathing, the wires of the lamp being respectively
attached to the metallic coating of the screw-thread, and with the metallic plug or
sheathing, substantially as hereinbefore described and illustrated in Figure 5 of the
accompanying drawings.
8. An incandescent electric lamp socket or holder having a block of porcelain, or
the like, in combination with metallic terminal pieces inserted in holes or pockets
in the said block and retained in position by means of screws or equivalent
fastenings pressed through lateral holes in the block into the said terminal pieces
substantially as hereinbefore described and illustrated in Figures 6 and 7 of the
accompanying drawings.
9. For use in incandescent electric lamps, sockets consisting of a block made of
insulating material and provided with holes for the reception of terminal pieces;
consisting each of the combination of a thin metal tubular case of less diameter at
one end than at the other end, so as to form a shoulder both on the exterior and in
the interior of the case; a buffer fitted to slide in the end of the case of least
diameter and provided with a head, rim or flange to rest on the shoulder in the
case, a spring bearing at one end on the head, or flanged end of the buffer and at
the other end against a stationary block fitted in the larger end of the case and to
which one of the conducting wires is attached substantially as herein before
described and illustrated in Figure 6 of the accompanying drawings.
10. Terminals for use with incandescent electric lamp sockets constructed of
insulating material as hereinbefore described, the said terminals consisting each of
a block of metal to which one of the conducting wires is attached and to which is
connected one end of a spring which projects at its other end beyond porcelain,
substantially as shewn in Figures 4 and 8 of the accompanying drawings.
11. Terminal pieces for use with incandescent electric lamp sockets constructed
as hereinbefore described, the said terminal pieces consisting each of a metal block
to which one of the conducting wires is attached, the said block being of such a
length as to project outside the hole in the base of the socket and having secured to
the projecting end a spring plate of segmental shape substantially as herein before
descrit ed and illustrated in Figure 9 of the accompanying drawings.
12. In incandescent electric lamp sockets or holders made of porcelain or the like,

page_text: the combination with a rim or shoulder formed round the exterior of the base of
the holder, of a screw threaded tightening ring to engage the rim and a metallic
covering piece or cap having a nozzle or opening in the centre thereof for
attachment to an electrolier, or the like, the said covering piece also having a screw
threaded rim fitting over the porcelain base and engaging with the screw thread on.
the tightening ring whereby the whole of the parts constituting the socket or
holder are rigidly and firmly connected together substantially as hereinbefore
described and illustrated in Figure 6 of the accompanying drawings.
13. In incandescent electric sockets or holders made of insulating material the
combination with a rim or shoulder formed round the exterior of the base of the
socket or holder, of a metal tube having at one end bayonet slots therein to engage
with projections on the cap or base of the lamp, and at the other end a projecting
rim or flange to bear against the under side of the rim or shoulder on the base of
the socket,.and a projection to engage in a notch or recess in the said rim; a
metallic covering piece or cap provided with means for attachment to a fixture, the
said covering piece having a screw threaded rim fitting over the end of the porcelain
base, and engaging with a screw threaded tightening ring provided with an internal
shoulder to bear against the underside of the flange or rim on the metallic tube so
that by screwing this tightening ring onto the rim of the covering piece the whole
of the parts comprising the combination are rigidly and firmly connected together
substantially as hereinbefore described and illustrated by Figure 7 of the accom-
panying drawings.
14. An incandescent electric lamp socket or holder made of insulating material
in the shape of a cup, and having a metal projection in the centre of the closed end
and a spring contact piece in combination with a lamp base or cap made of insulating.
material and provided with contact pieces arranged to connect respectively with the
central projection and with the spring in the socket or holder substantially as.
herein before described and illustrated in Figure 3 of the accompanying drawings.
15. Sockets or holders for incandescent electric lamps made of porcelain or the
like with bayonet shaped grooves in the interior for the reception of studs or
projections on the lamp cap or base substantially as hereinbefore described and
illustrated in Figure 10 of the accompanying drawings.
16. Sockets or holders for incandescent electric lamps made of porcelain or the
like and provided in the interior with a metal band having bayonet slots therein
for the reception of studs or projections on the lamp cap or base substantially
as herein before described, and illustrated in Figure 11 of the accompanying
drawings.
17. An incandescent electric lamp socket made of insulating material in the form
of a cylindrical shell with a closed end integral therewith in combination with a
metallic post inserted in a recess or pocket in the said end or bottom, a spring
secured to the metal post and shaped to enter a depression or recess in the end or
bottom and a key shaft projecting through the cylindrical shell and carrying a
contact block, key, or switch adapted to engage and disengage the spring substan-
tially as hereinbefore described with reference to Figure 13 of the accompanying
drawings.
18. Sockets or holders for incandescent electric lamps made of porcelain or the
like and having a shoulder formed on the exterior with holes therein through
which screws or like fastenings can be passed to attach the holder to a support
substantially as bereinbefore described and illustrated in Figure 15 of the
accompanying drawings.
19. Sockets or holders for incandescent electric lamps, made of porcelain or the
like with an enlargement or shoulder in combination with a ring of light metal
as shewn in Figure 14 to engage with the enlargement or shoulder and provided
with a flange through which screws orlike fastenings can be passed to secure the
holder to a wall, partition or other support substantially as hereinbefore described.
20. In combination with the incandescent electric lamp sockets or holders

page_text: herein before described, means for attaching thereto a lamp shade or globe
substantially as hereinbefore described.
21. Incandescent electric lamp sockets or holders formed as herein before
described and claimed and with the external metal parts coated with waterproof
preparation substantially as and for the purpose hereinbefore described.
22. The several constructions of incandescent electric lamp bases or caps and
sockets or holders and combinations of such bases or caps, and sockets or holders
as hereinbefore described and illustrated respectively in the several figures of the
accompanying drawings.
Dated this 25th day of June 1896.
JOHNSONS & WILLCOX,
47 Lincoln's Inn Fields, London, W.C., Agents.