Improvements in Holders for Incandescent Electric Lamps.
Year: 1891

page_text: COMPLETE SPECIFICATION.
Improvements in Holders for Incandescent Electric Lamps.
We, CHARLES MARK DORMAN of 24, Brazenose Street, Manchester, in the
County of Lancaster. Electrical Engineer, and REGINALD ARTHUR SMITH, of
24 Brazenose Street, Manchester in the County of Lancaster, 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—
Our invention relates to that class of lampholder which is used with capped
incandescent lamps, and consists in arranging the necessary parts so that in a holder
of moderate size the insulated wires can be brought right through separate holes
in the insulated base of the lampholder and safely and easily coupled up on the
front.
The methods whereby we attain this object can be best understood from an
examination of the drawings accompanying this Specification, wherein
Fig. 1. is a section of the complete lampholder on the line a. a;
Fig. 2. is a plan of the insulating base removed from the case with the terminals
in position;
Fig. 3. is an outside elevation of the complete holder; and
Fig. 4. is a side elevation of one of the terminal plates.
It will be seen that we screw the plunger-casings a. directly into the insulating
base, thereby securing the terminal plates c. to the insulating base b.
Although by this means we dispense with the screws or bolts which are usually
used for this purpose, we prefer to gain additional space by turning up the terminal
plates c., so that while in plan they partially cover up the holes d. through which
the insulated wires are drawn, yet, as will be seen in the elevation Fig. 4. plenty of
room is left for the stripped wire to be passed round the screw-head e., which would
not be the case were the terminal plates left flat.
By these methods we are enabled without enlarging the ordinary socket tube to
arrange inside it an insulator fitted with our improved terminals as shown, and yet
leave ample clearance between the parts.
For the purpose of securing the various parts of the holder together, we fit the
socket tube with two or more projecting tabs o., which, while engaging in
corresponding slots in the metal base h., so preventing the turning round of the
tube in the metal base, also allow of the tube being secured to the base by means
of the nut k. pressing on the tabs o.
The insulating base whose turning movement is limited in the usual manner is
clamped securely between the socket tube and the metallic base h.
When these holders are required to carry a reflecting shade we generally clamp
the shade between the nut k. and a loose washer 1. by means of the spiral spring
nut m. which engages with the projecting tabs . on the socket tube f. This nut m.
can be very easily screwed on and off the socket tube and forms a convenient and
elastic support for the shade.
Having now particularly described and ascertained the nature of our said inven-
tion, and in what manner the same is to be performed, we declare that what we
claim is -
1. In lampholders for capped incandescent lamps the method of securing the
terminal plates by screwing the plunger casings directly into the insulating base
substantially as and for the purposes described.
2. In lampholders for capped incandescent lamps the method of turning up the
terminal plates at an angle substantially as and for the purposes described.

page_text: 3. The combination of plunger casings screwed directly into the insulating base
with terminal plates turned up at an angle substantially as and for the purposes
described in this Specification.
4. In lampholders for capped incandescent lamps the method of securing the
socket tube to the metallic base by means of a nut pressing on tabs projecting
from the tube, the said tabs engaging in slots in the metallic base and so preventing
the tube revolving therein substantially as and for the purposes described.
5. The improved lampholder as a whole substantially as described and shown.
Dated this 25th day of November 1891.
CHARLES MARK DORMAN.
REGINALD ARTHUR SMITH.