Improvements in Lampholders for Incandescent Electric Lamps.
Year: 1892

page_text: Date of Application, 12th Aug., 1892-Accepted, 17th Sept., 1892
COMPLETE SPECIFICATION.
Improvements in Lampholders for Incandescent Electric Lamps.
We, CHARLES MARK DORMAN of Ordsal Works, Salford in the County of
Lancaster, Electrical Engineer and REGINALD ARTHUR SMITH of Ordsal Works,
Salford 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 bayonet socket lampholders for capped incandescent
lamps, and in part relates to the arrangement of a switch in same, and to improve-
ments in the details of the holder.
In socket lampholders in which the current is conveyed to the lamp through
plungers working in plunger cases or guides it often happens that owing to
the plunger being a bad fit in the guide the electrical resistance due to the
imperfect contact causes heating to take place which besides being a wasteful loss
of energy causes a deterioration of the lampholder to take place.
To overcome this defect we split up the plunger as shown at a. in Figs. 1 and 2.
which are enlarged views, and by giving the forked prongs of the plunger a certain
amount of outward set ensure a good sliding contact between them and the plunger
guide b. which is shown in half section and half elevation in Fig. 3.
Our improvements relating to lampholders containing switches are shown in
Figs. 4. 5. 6. and 7.
Fig. 4. is a section through a switch-lampholder showing the position and shape
of the insulating switch-base c; the working mechanism d of the switch being
mounted on one side of the base c. and the other side reserved entirely for the
terminals e. to which the wires are attached. There is then no danger of the wires
coming into contact with any part of the working mechanism of the switch.
Fig. 5. is an elevation with cap removed showing that side of the insulating
base c which bears the working mechanism d of the switch and Fig. 6 is a similar
elevation of the other side showing the terminals e e.
Fig. 7. is a view of the switch handle looking from the inside of the switch.
The position and shape of the insulating base c. is so arranged that the holder
can be screwed on to a bracket through which the wires are projecting without the
wires becoming twisted or deranged. After the holder has been screwed on to the
fitting the wires can be conveniently coupled up to the terminals e. e.
Having now particularly described and ascertained the nature of our said
invention, and in what manner the same is to be performed we declare that what we
claim is:
1. In lampholders for incandescent electric lamps the method of ensuring a good
electrical contact between the plungers and the plunger guides by splitting the
plungers and giving the forked prongs an outward set substantially as and for the
purposes described.
2. In lampholders containing switches the method of arranging the centre-line
round which the switch mechanism revolves at right angles with the centre-line of
the lamp; one face of the switch base being reserved for the working mechanism of
the switch and the other reserved for the terminals for coupling up substantially as
and for the purposes described.

page_text: 3. The combined switch and lampholder as a whole substantially as described
and shown in this Specification.
Dated this 11th day of August 1892.
CHARLES MARK DORMAN.
REGINALD ARTHUR SMITH.