IMPROVEMENTS IN INCANDESCENT ELECTRICAL LAMPS
Year: 1882

page_text: LETTERS PATENT to Henry Lea of Birmingham in the County of Warwick
Civil Engineer for an invention of "IMPROVEMENTS IN INCANDESCENT
ELECTRICAL LAMPS."
PROVISIONAL SPECIFICATION left by the said Henry Lea at the Office of
the Commissioners of Patents on the 9th May 1882.
HENRY LEA of Birmingham in the County of Warwick Civil Engineer
"IMPROVEMENTS IN INCANDESCENT ELECTRICAL LAMPS
"
My invention has for its object to facilitate the connecting and disconnecting of
incandescent electrical lamps to and from the brackets and supports carrying them
and simultaneously connecting and disconnecting the carbon filament of the lamp
with the electrical conductors by which electricity is supplied to the lamp.
An incandescent electrical lamp as ordinarily constructed consists of a filament
of carbon enclosed within an exhausted glass globe and connected with two
platinum wires passing through the globe, the said wires serving to connect the
carbon filament with external conducting wires which supply the current of
electricity by which the filament of carbon is made incandescent A mechanical
holder carries the globe and the conducting wires, binding screws and other
appliances.
My improvements consist in simplifying the holder and parts connected there-
with so as to facilitate the removal and replacement of the lamp when required.
In an incandescent electrical lamp made according to my invention the hollow
glass globe is surmounted by a hollow neck the upper end of which has the form
of a transverse tee shaped head at each extremity of which one of the aforesaid
platinum conducting wires is brought out and bent into a small loop which is
folded down and pressed closely against the glass.
The holder consists of a body of any suitable non-conducting material two
metallic springs and two binding screws.
The tails of the springs are bent into such a form and placed at such a distance
apart as to grip and hold securely the head of the globe when forced up between
them and at the same time to form metallic contact between each spring and the
platinum wire upon which it presses.

page_text: The springs are attached to each side of the holder near its upper end, each
spring being suitably folded into notches formed in the holder and being held in
position by a binding screw screwing into the substance of the holder The lower
portion or tail of each spring occupies a vertical groove in the side of the holder
and a transverse groove in the bottom of the holder unites the two vertical side
grooves. The width of the transverse groove is no greater than will admit the
shorter axis of the tee shaped head of the lamp globe and when the lamp is pushed
upwards from below its head is forced between the tails of the springs the lamp
being thus suspended and electrical contact simultaneously made.
The holder is attached to a bracket or pendant by screwing or otherwise.
The oblate form of the tee shaped head prevents the possibility of inserting it
into the holder in a wrong direction and also prevents the possibility of turning
the globe and the platinum loops out of contact with the springs when once the
globe is in position.
Holders made according to my invention are inexpensive and can be conveniently
made by machinery and incandescent electrical lamps having my improvements can
be quickly removed and replaced even in the dark without risk of mistake or
accident.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Henry Lea in the Great Seal Patent Office on the 2nd November
1882,
HENRY LEA of Birmingham in the County of Warwick Civil Engineer.
"IMPROVEMENTS IN INCANDESCENT ELECTRICAL LAMPS
"
My invention has for its object to facilitate the connecting and disconnecting of
incandescent electrical lamps to and from the brackets or supports carrying them
and to simultaneously effect the connection of the carbon filament of the lamp with
or the disconnection of the said carbon filament from the electrical conductors by
which electricity is supplied to the lamp.
An incandescent electrical lamp as ordinarily constructed consists of a filament
of carbon enclosed within an exhausted glass globe and connected with two
platinum wires passing through the globe, the said wires serving to connect the
carbon filament with external conducting wires which supply the current of
electricity by which the filament of carbon is made incandescent. A mechanical
holder carries the globe and the conducting wires, binding screws and other
appliances.
My improvements consist in simplifying the holder and parts connected there-
with so as to facilitate the removal and replacement of the lamp when required.
In an incandescent electrical lamp made according to my invention, the hollow
glass globe is surmounted by a hollow neck, the upper end of which has the form
of a transverse T shaped head at each extremity of which one of the aforesaid
conducting wires is brought out and bent into a small loop which is folded down
and pressed closely against the glass. The holder consists of a body of any suitable
nonconducting material two metallic springs and two binding screws. The tails of
the springs are bent into such a form and placed at such a distance apart as to
grip and hold securely the head of the globe when forced up between them and at
the same time to form metallic contact between each spring and the platinum wire
upon which it presses. The springs are attached to each side of the holder near its
upper end, each spring being suitably folded into notches formed in the holder and
being held, in position by a binding screw screwing into the substance of the
holder. The lower portion or tail of each spring occupies a vertical groove in the
side of the holder and a transverse groove in the bottom of the holder unites the
two vertical side grooves.
The width of the transverse groove is no greater than will admit the shorter
axis of the T shaped head of the lamp globe and when the lamp is pushed upwards
from below its head is forced between the tails of the springs, the lamp being thus
suspended and electrical contact simultaneously made. The holder is attached to a
bracket or pendant by screwing or otherwise.
The oblate form of the T shaped head prevents the possibility of inserting it into
the holder in a wrong direction and also prevents the possibility of turning the
globe and the platinum loops out of contact with the springs when once the globe
is in position.
I will now proceed to describe with reference to the accompanying Drawing the
manner in which my invention is to be performed.
Figure 1 represents a vertical section of an incandescent electrical lamp constructed
according to my invention and Figure 2 is an elevation of the same with the
springs removed, the section Figure 1 being taken in a plane at right angles to
that of the elevation Figure 2. The other Figures represent separate parts and.
details of the lamp as hereinafter explained.

page_text: The same letters of reference indicate the same parts in the several Figures of
the Drawings.
A is the exhausted glass globe of the incandescent lamp shown separately in
elevation in Figures 3 and 4 and plan of top in Figure 5. The solid head B of the
globe A contains the usual platinum wires C C to which are attached the two
extremeties of the carbon filament D. The outer end of each platinum wire C
projects from one of the extremities or poles of the solid head B and is bent into
the form of a loop B¹ which is folded down close to the glass, the extreme end of
the wire of the loop being caused to reënter the glass of the solid head as shown
at d Figure 1 for the purpose of affording a more secure attachment. By
preference the loop is made as shown in Figure 6 and being folded at the dotted
lines a,
b the smaller loop c and the end d of the wire are made to reënter the glass
of the solid head whereby the security of the attachment is still further
increased. Figure 7 represents on a large scale the configuration of the
platinum wire B' after it has been bent and fixed in the head B of the globe A.
The holder consists of a globular body E shown separately in sectional elevation
in Figure 8 and elevation in Figure 9 and plan and section in Figures 10 and 11.
The said body E is surmounted by a nearly cylindrical head F. A transverse
slot G in the globular body receives the solid head B of the glass globe and four
small slits H in the cylindrical head receive the turned in upper ends of the
springs K, K. Figure 12 represents one of these springs in front elevation and
Figure 13 represents the same in side elevation; Figure 14 represents a plan of
the top of the spring; Figure 15 is a sectional plan of the head of the holder with
the springs in their places on the said holder. Each of the said springs consists of
a transverse head L bent to fit the flattened side of the nearly cylindrical head F
of the holder and hooked at I, I to enter the slits H, H. The tail M of the spring
is curved as shown in Figures 1 and 13 so as to fit one pole of the lamp head B.
Each spring is by preference made of two or more thicknesses of metal whereby
greater elasticity is obtained but a single thickness may be used if desired;
N, N are two binding screws which serve the double purpose of securing the
springs to the head of the holder and of attaching the fine wire leads or
conductors O, O by which the current of electricity is conveyed through the lamp;
P is a screwed stem by which the lamp may be attached to a bracket or pendant
or other ornamental fitting.
In order to place the exhausted globe A of the incandescent lamp in the holder,
the head B of the globe is forced between the blade springs K, K where it is held
in position by the poles of the said head entering the bows of the springs.
Metallic or electrical contact is at the same time made between each spring and
the platinum wire loop upon which it bears and the electrical current is thus
directed through the carbon filament D in the globe A of the lamp. To withdraw
the head of the globe it is only necessary to depress it out of the holder, in doing
which the head of the globe forces asunder the blade springs and becomes liberated
therefrom.
I do not limit myself to the precise form or arrangement of the parts shown in
the drawings; the body of the holder for example may be made wholly cylindrical
or wholly rectangular or partly cylindrical, globular and rectangular. The
expanded head L of the springs K, K may be dispensed with and the springs may
be secured to the head of the holder by the binding screws only.
Holders made according to my invention are inexpensive and can be conveniently
made by machinery and incandescent electrical lamps having my improvements can
be quickly removed and replaced even in the dark without risk of mistake or
accident.
"
Having now described the nature of my invention and the manner in which the
same is to be performed I wish it to be understood that I claim as my Invention of
Improvements in incandescent electrical lamps." ;-
First Constructing the head of the exhausted globe of the lamp of a T shape or
other analogous shape as herein before described and illustrated in the accompanying

page_text: Drawing, whereby it can only be inserted into the holder in the position
suitable for preventing it turning, the said position also securing the required
metallic or electrical contact between the filament in the globe and the wires by
which the electricity is conducted to the lamp.
Secondly The combination of the T shaped or other like head of the
exhausted globe, the slotted holder and the bent springs substantially as and for
the purposes herein before described and illustrated in the accompanying Drawing.
In witness whereof I the said Henry Lea have hereunto set my hand and
seal this Thirtieth day of October in the year of our Lord one thousand
eight hundred and eighty two.