Improvements in Conductors in Telescopic Standard Lamp Holders for Electric Lamps.
Year: 1893

page_text: Date of Application, 7th Mar., 1893-Accepted, 2nd June, 1893
COMPLETE SPECIFICATION.
Improvements in Conductors in Telescopic Standard Lamp Holders
for Electric Lamps.
ANTHONY GEORGE NEW of Palace Chambers, Westminster, in the County of
London, Electrical Engineer, do hereby declare the nature of this invention and in
what manner the same is to be performed, to be particularly described and ascertained
in and by the following statement :-
The object of the present invention is to provide a means of dispensing with
the sliding contacts usually employed in extensible or telescopic standard lamp-
holders fitted with incandescent (or other) electric lamp.
The use of sliding contacts is attended by a multiplicity of disadvantages
namely sparking wearing away and oxidation of their surfaces which the present
arrangement is designed to obviate.
This is attained by coiling an ordinary insulated double flexible conductor-
attached at the end to the top of the sliding tube and electrically connected with
the lamp and at the other to terminals at the bottom of the standard inside the
moveable tube of the extensible lamp-holder, as will be seen by reference to
Figures 1 and 2 of the sheet of accompanying drawings both of which are vertical
sections. The insulated conductor is coiled in the form of a helicoidal spring the
various turns of which are as shown in Figure 1 as close together as practicable.
When the lamp-holder is extended into the position shown in Figure 2 the coiled
conductor extends equally with it. It is an arrangement to ensure the conductor
returning into the position shown in Figure 1 when the lamp-holder is brought
back to its original condition, that the essential feature of my invention consists.
To effect this I construct the flexible conductor of phosphor-bronze (or other
metal or alloy of high conductivity) which is hammered or tempered till it attains
a sufficient degree of elasticity. The coiled conductor then forms of itself a
helicoidal spring and is in consequence capable of expanding and contracting in the
required manner whenever the tube of the lamp-holder is raised or lowered. I also
and preferably effect the same end by employing an ordinary non-elastic insulated
flexible conductor coiled as described and shown but having each or every of its
turns secured to a long thin piece of india-rubber or other extensible material one
end of which is secured to the top end of the moveable tube of the lamp-holder,
and the other to the bottom of the fixed standard. This piece of india is shewn in
the drawing by a long thin black line. When the lamp-holder is raised the coiled
conductor extends into the position shown in Figure 2 stretching the india-rubber.
On lowering the upper part of the lamp-holder the flexible conductor is brought
back to and retained in the position shown in Figure 1.
Having now particularly ascertained and described the nature of my said inven-
tion and the manner in which it is to be performed what I claim is
1. The employment of a helicoidal electric conductor inside extensible or
telescopic lamp holders or standards to obviate the employment of sliding contacts
the said conductor being composed of elastic metal or rendered expansile and
contractile by attachment to india-rubber essentially as shown and described.
Dated this 7th day of March 1893.
ANTHONY G. NEW.