IMPROVEMENTS RELATING TO INCANDESCENT ELECTRIC LAMPS
Year: 1884

page_text: I, HUGH WATT, Managing Director of The Maxim-Weston Electric Company,
Limited, of 32 Queen Victoria Street, in the City of London, do hereby declare
the nature of said Invention for "IMPROVEMENTS RELATING TO INCANDESCENT
ELECTRIC LAMPS" 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 incandescent electric lamps and comprises various
Improvements hereinafter specified. These lamps may be said to consist of two
main portions, that is to say, first the lamp proper or glass globe containing the
carbon filament, and secondly the device by which the said globe is held and
supported; in the following description I term the first portion the lamp and the
second portion the socket or holder.
The objects of this Invention are to ensure and maintain good contact between
the terminals of the lamp and those of the socket or holder, whilst permitting the
lamp to be turned in its holder in either direction, and also to prevent the
displacement of the lamp, and injury thereto by the attempts of unskilled persons
to remove it from its holder in such a manner as to injure the mechanical or
electrical connections.
To accomplish these objects I provide a socket or holder with spring contact
points or terminals so arranged as to correspond with, and bear or press against, the
lamp-terminals when the lamp is in place; and I construct the lamp and holder in
such a manner that this contact may be preserved and the lamp held in place by
locking devices which permit it to be turned in its seat in either direction.
In the accompanying Drawing
Figure 1 is an elevation of an incandescent electric lamp and a holder constructed
in accordance with the present Invention.
Figure 2 is a central vertical section of the same, part of the said lamp being
shewn in elevation.
Figure 3 is an elevation, and
Figure 4 an inverted plan of an attachment to be used in combination with the
lamp, as hereinafter described.
Figure 5 is a plan of a cap forming part of the holder.
Figure 6 is a horizontal section of a portion of the said holder.

page_text: Figure 7 is an elevation, partly in vertical section, shewing a modified
arrangement of the holder.
Figure 8 is a section, at right angles to that shewn in Figure 7, of a portion of
the said holder.
Figure 9 is a horizontal section of the same.
· Figure 10 is an elevation shewing a modification of the attachment shewn in
Figure 3.
Figure 11 is a horizontal section of the same.
Figure 12 is a horizontal section illustrating a modification of the part shown in
Figures 6 and 9.
Figure 13 is a view, partly in elevation and partly in central vertical section,
shewing a modified form of my lamp and socket or holder.
Figure 14 is a horizontal section on the line x, x, Figure 13.
Figure 15 is a similar view to Figure 13 shewing a further modification of the
said lamp and socket or holder, and
Figure 16 is a horizontal section on the line y, y, Figure 15.
In carrying my said Invention into practice I apply to the neck of an ordinary
incandescent electric lamp A a cylindrical cup or base B of insulating material,
having a projection b on its lower end. The material of which this cup or base is
composed may be india-rubber, vulcanite or the like, and the manner of applying
the said cup or base may be varied as desired.
Around the lower edge of the part B, I place a metal rim a, to which one of the
conductors of the lamp is secured. The other conductor is passed through the
projection band soldered to a plate a secured to the end thereof.
Ears or
lugs C, C, are formed on, or secured to, the sides of the insulating base B.
The socket or holder consists of the following parts, viz. :-Å shell or box D of
sheet metal lined with insulating material, to which are secured contact springs E. F
arranged in proper position to encounter and press upon the terminal plates of the
base B; these springs form the terminals of conductors arranged within the box D.
The construction and arrangement of these terminals may be varied or modified. I
prefer, however, to use as the lining & a cup of vulcanite or other insulating
material, with a perforation in the bottom through which the projection b extends
when the lamp is in place. In this cup I secure the contact spring or plate E and
on the under side of the cup I secure the other contact spring or plate F; these
springs are placed in such positions that they will bear respectively upon the rim a
and the plate o when the lamp is in place.
The shell D is made with an internal flange 9 which is notched or cut away at
the points e, e.
The above described devices constitute the essential portions of the holder. I
usually employ in addition to them, a locking device consisting of a cap G with an
opening slightly greater in diameter than the base B and having notches ff. The
cap G is secured to the casing or shell D by screws h passing through slots h¹ in
the cap G and entering the sides of the said shell. In conjunction with the
shell D I sometimes use a base or support H containing a device for making and
breaking the circuit. A useful form of device for this purpose is shown.in the
Drawing to illustrate its application.
In using my improved socket or holder, the base B attached to a lamp is inserted
into the casing D, the lugs C passing through the notches e. The lamp is then
turued to carry the lugs C under the flange or rim g. If a cap G be used, it is
first turned so that its notches correspond with the notches e and, after the lamp
is in place, it is turned so as to cover the said notches and thereby prevent the
accidental removal of the lamp from the socket. When the lamp is thus secured
in place, the spring E will be in contact with the rim a, and the spring F will be
in contact with the plate c, as above explained.
When the cap Gis dispensed with, the lamp may be prevented from turning
and becoming detached from the socket or holder, by forming, in the flange or rim
of the latter, depressions K, as shown. in Figures 8 and 9. The lamp, when

page_text: inserted in a socket or holder thus formed, is turned until the lugs C enter these -
depressions, where they will be held by the upward pressure, of the contact springs
E, F, the latter forming a spring-seat for tho lamp.
The lugs C, instead of forming a part of the base B, may be secured thereto in
any convenient manner. For example, as illustrated in Figures 10 and 11,
wherein L indicates a metal collar provided with ears or lugs C. This collar is
fitted upon the base B and held in place by the points, m.
It is obvious that, in lieu of forming the ears or lugs on, or attaching them to,
the base B, and using the same in conjunction with the flanged socket or holder,
the base B may have vertical and horizontal grooves and the socket or holder be
provided with lugs to enter the said grooves and hold the lamp in position.
This form of construction is hereinafter described.
The object, in either case, is to allow the lamp to have a rotary movement in its
holder without injury to the connections. This is extremely desirable on account
of the liability to accidental breakage of the holder by persons attempting to
remove the lamp therefrom by turning it. Moreover, by my Invention, a spring
contact is always maintained while the lamp is in place, which contact is not
impaired by a rotary movement of the lamp.
According to the modification of my said Invention illustrated in Figures 13 to
16, I provide a cylindrical base B having the projection b, the ring or rim a and
the plate c; also a cylindrical shell D having a cup or lining d of insulating
material, as above described. Moreover a spring blade or plate E is secured in the
bottom of the cup d in position to make contact with the ring or rim a when the
lamp is in place; and another spring F is secured under the cup d in position to
press upon the cap or plate c on the projection 6, which latter passes through the
perforation in the bottom of the cup d, when the lamp is in place, as above
described. It may be stated that any other arrangement of spring terminals than
this may be. adopted which will provide a spring seat for the lamp and maintain
contact with the conductors of the same in whatever position the lamp may be
turned while in the socket or holder.
h' is a wooden or metal ring held in place in the shell D by the flange g¹; and
K, K' are projections or ears on the said ring extending inwardly. To permit the
lamp to be introduced into the socket or holder, vertical grooves m³ are cut in the
base B, and for retaining it in place a groove n is cut around the base B near the
glass globe of the lamp.
To insert the lamp, it is held so that the grooves m¹ and projections K¹ corre-
spond with each other. The lamp is then pressed down upon its spring seat and
turned to bring the projections K¹ into the groove n. The upward pressure of
the springs E, F holds the lamp firmly in this position.
The same object can be obtained by other means, for example, those shewn in
Figure 15, wherein the shell D, the cup or lining d and the contact plates E, F are
substantially the same as those above described. But in this modification spring
catches are adapted to enter the horizontal groove n in the base B; and the
vertical grooves m³ are dispensed with. The insertion of the lamp forces aside the
catches L' which enter the groove n when the lamp is pressed down firmly in its
seat.
Any suitable catches may be employed for this purpose. Those shown consist of
spring levers pivoted in recesses in the cup or lining d. Pins M pass through the
sides of the shell D and are used for disengaging the catches when it is desired to
remove the lamp from the socket or holder.
Having now particularly described and ascertained the nature of my said
Invention and in what manner the same is to be performed I declare that what
I claim is
First. The combination, with an incandescent lamp and terminal plates secured
to the same, of a holder or socket, spring contacts therein forming a seat for the
lamp, and means substantially as described for locking or retaining the lamp in

page_text: position against the springs and permitting it to be turned, substantially as, and
for the purpose specified.
Second. The combination, with an incandescent lamp having lugs or ears on
the sides of its neck or base, of a socket or holdor having a flanged rim with
notches cut therein and a perforated cap or cover with notches corresponding to
those in the holder, all constructed and arranged to operato substantially as set
forth for the purpose specified.
Third. The modification of my Invention wherein I combine, with an incan-
descent lamp and a cylindrical base having a groove or grooves as described, a
socket or holder having projections, or equivalent parts for entering the grooves
in the lamp-base and retaining the same in position, substantially as set forth.
10th - 1004