Improvements in Electric Light Fittings...
Year: 1890

page_text: Date of Application, 15th Feb., 1890-Accepted, 22nd Mar., 1890
COMPLETE SPECIFICATION.
Improvements in Electric Light Fittings...
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 he performed, to be
particularly described and ascertained in and by the following statement :-
Our invention relates principally to that class of electric light fittings in which the
incandescent lamp, together with its shade or reflector, is suspended by the wires
conveying the current from a ceiling plate.
Our improvement consists partly of forming the metallic terminals of the lampholder
and ceiling plate with a projecting hook round which the wire conveying current can
be twisted. The weight of the fitting is then borne by these hooks instead of by the
terminal screws.
Our improvement also consists in using a novel form of spiral spring nut by which
the reflector or shade is held on to the lampholder. This spring nut gears in two or
more projections on the front of the holder, and is screwed on and off like an ordinary
nut, the projections on the front of the holder, serving the purpose of the threads of a
male screw.
Our improvement further consists in forming an independent. cord-grip arrangement
in the cover of the ceiling plate, consisting of a screwed nozzle through which the
wires pass, which nozzle when screwed home squeezes the wires which are led one on each
side of a loose disc between the nozzle and the cover of the ceiling plate.
Referring to the drawings accompanying this specification :-Fig. 1. is a section of
a ceiling-plate fitted with our improved terminals. The end of the line wire carrying
current to the terminal is attached to the screw a, the-wire conveying the current to
the lampholder being attached to the same terminal by the screw b, and is also twisted
round the hooked part as shown, thus relieving the screw b of the weight of the
fitting.
Fig. 2. is a half elevation and half section of our improved holder for incandescent
lamps which are fitted with base caps. Fig. 3. is a plan of the same holder with cover
removed showing the hooked terminals. Fig. 4. is a section of same holder on the
line xx. Fig. 5 is a half elevation and half section of our improved holder for
incandescent lamps which are fitted with base loops. Fig. 6 is an underplan and
Fig. 7 a section on the line y. y. of the porcelain insulating body piece which is
common to both the holders shown in Figs. 2 and 5. Fig. 8 is a section of the lamp
support shown in Fig. 5. Fig. 9. is a section of a ceiling plate fitted with our improved
cord-grip.
The suspension wires are attached to the terminals of the lampholders by the
screws c, and are then twisted round the hooked parts of the terminals as shown in the
sections Figs. 2 and 5, thus taking the strain off the screws c c.
The compression springs d and the tension springs e are passed through holes in
the terminal plates and soldered. The springs d are fitted at the lamp end with a
plunger peg, while the springs e are fitted with a hook.
The shades are held up by the spiral spring nuts g, which can be screwed on and
off like an ordinary nut, engaging with the teeth or projection h.
A washer is interposed between the spring nut and the shade, and in the case of the
holder shown in Fig. 5 this washer is provided with two projecting arms k to support
the lamp. This arrangement is also shown in Fig. 8.
Since the weight of the fitting is directly borne by the terminals on the body of the
lampholder the cover I need not be secured by screws or bayonet joints, and is there-
fore simply made to spring on the body of the holder as shown.

page_text: The action of the cord-grip in the ceiling plate shown in Fig. 9 will be understood
from the drawing. The wires from the terminals of the ceiling plate are led through
a small hole in the cover, passing one on each side of the disc m, then through a hole
in the washer n, and through the nozzle p." When the nozzle p is screwed home the
wires are securely gripped. The disc m and the washer should be constrained from
revolving by pegs or other similar contrivances.
137
Having now particularly described sand 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 ceiling plates and lampholders for incandescent electric lamps the method of
forming the terminals with hooks round which the wires can be twisted in order to
take the strain off the terminal screws substantially as and for the purposes described.
2. In lampholders for incandescent electric lamps the method of carrying the shade
or reflector by a spiral spring nut, which gearing in projections on the holder. serving
the office of the threads of a male screw, can be screwed on and off like an ordinary,
nut substantially as and for the purposes described.
3. In ceiling plates or wall-connectors, the method of forming a cord-grip in the
cover, consisting of a screwed nozzle through which the wires pass, which nozzle when
screwed home squeezes the wires which are 'led on each side of a louse disc between
the nozzle and the cover of the ceiling plate substantially as described and shown in
:the drawings.
4. The lampholder shown in Fig. 2 as a whole substantially as described and
shown.
5. The lampholder shown in Fig. 5 as a whole substantially as described and
shown.
D
1
CHARLES MARK DORMAN.
REGINALD ARTHUR SMITH.