IMPROVEMENTS IN ELECTRIC LIGHT FITTINGS
Year: 1886

page_text: Date of Application, 12th Mar., 1886.
Complete Left, 11th Dec., 1886.
Complete Accepted, 1st Feb., 1887.
We ROOKES EVELYN BELL CROMPTON of Mansion House Buildings Queen
Victoria Street in the City of London Engineer and WILLIAM AUGUST KYLE of Arc
Works Chelmsford in the County of Essex Engineer do hereby declare the nature of
our invention for IMPROVEMENTS IN ELECTRIC LIGHT FITTINGS to be as follows:-
Our invention relates to Electric Light fittings either for incandescent or are lamps
and which may be of pendant or bracket form.
For certain purposes such as for concentrating the light given by the lamp on to a
workman's bench or draughtsman's table or any similar purpose it is desired to supply
an adjustable fitting which can be arranged so as to throw a more or less concentrated
beam of light in any required direction and at any required height.
One part of our invention relates to this particular object, we suspend a pendant
fitting containing one or more incandescent lamps (or in some cases one small arc
lamp) from the ceiling or any suitable overhead attachment by means of one or more
flexible conducting wires.
For suspending purposes we sometimes use only one flexible cord which contains
a pair of insulated conductors covered with braid or other material to resist external
injury.
This cord is attached overhead to a ceiling plate then passes down under and round
a counterweight then over a pulley fixed alongside the ceiling plate thence down to
the pendant fitting.
In some cases we provide two and in other cases three suspending cords or wires.
One of them may be the twin flexible cord conveying the electricity and the other
two plain cords or wires, the two or three of them passing over two or three pulleys
as the case may he and being attached to a counterweight which may be either solid
and centrally placed or may be of ring form and thus pass outside the three suspending
wires.
In cases where we require the pendant fitting to remain perfectly steady and free
from swinging or vibration we use the three suspending wires and place the three
pulleys above somewhat widely apart.
The pendant fitting itself may be provided with arrangements so that it can swivel
in either the vertical or horizontal angle or through both angles.

page_text: To provide for swivelling through the vertical angle only, a pair of trunnions are
attached to a casting forming the main body of the fitting at such a position that the
centre of gravity of the whole fitting passes as nearly as possible through the centre
line of these trunnions.
That part of the fitting which swivels consists of the lamp, lampholder, and reflector
which may be made of any required form. The whole of these are necessarily placed
to one side of the centre of gravity line passing through the trunnions.
In order to counterweight these parts on the other side of the centre line the switch
is placed and a block of lead or cast iron is attached so as to form a counterweight of
as little bulk as possible..
The flexible cord containing the conductors above mentioned passes from the switch
through a hole pierced in the bridle in which the trunnions revolve.
In cases where we suspend this fitting with two wires so as to prevent it revolving
in the horizontal angle, we sometimes mount two bridles on the above mentioned
trunnions and pass one flexible wire out through the hole in one, and the other wire
through the hole in the other.
It will be obvious that by adjusting the respective angular positions of these two
bridles on the trunnion and then clamping them: fast with clamping screws mounted
on the trunnion the whole fitting may be fixed in any desired vertical angle.
To effect an adjustment in the horizontal angle we fix at a position close above the
bridle or bridles above mentioned a pair of horizontal plates or frames the upper one
of which is suspended from the overhead attachment by the two or three suspending
cords before mentioned:
These cords pass through holes in the upper plate and are attached firmly to the
lower plate. It will be seen that the upper one of these two plates being fixed as
regards the horizontal angle relatively to the overhead attachment; if the lower plate
be revolved through a desired angle and again clamped to the upper plate, the whole.
fitting will revolve with it 'through the desired horizontal angle.
In some cases we mount this pair of plates above the counterweight arrangement
and close to the overhead attachment. This however, is only in such cases where,,the
attachment is easily accessible.
If a switch be required in the fitting it may be of any desired form but we usually
prefer a piston or plunger switch having an insulated tubular collar fixed outside, a
cylindrical plunger. When this plunger is in one position, a pair of, touching pieces
forming terminals of one wire of the circuit can make. contact, and complete the
circuit through the metallic portion of the plunger. When however the plunger is moved
endways so that the insulating cylinder comes between, the touching-pieces, the circuit
is broken..
Another form of switch which we provide to pendant lamp-fittings, is one which
may be operated by the simple act of slightly drawing the pendant itself downwards,
or the cord attached to the pendant at a convenient position may be.so moved.
'S.
In one method we fix at or near the overhead attachment two pairs of spring
contact clips. These contact clips consist, each of two metallic pieces. so. fixed; and
contrived that they press themselves firmly into close contact at their lower extremities
nt such times as no intervening object tends to force them apart.
The two ends of the wire.desired to. be connected, by, this, switch are connected..up
to these two pairs of clips so that when they. (the, clips) are connected contact is made
and the circuit is complete..
We form their upper ends with a. bell mouth to afford, easy entrance to a moveable..
metallic cross, bar of suitable form so that when pressed sideways. into the bell mouths..
it readily enters them slightly forcing the clips apart and making good metallic.
connection from one pair to the other pair. :
This imetallic cross bar may be, attached to a spring, or to a cord passing over, a
pulley to a 'counterweight or to any other device tending to draw it. upwards away.
from the bell mouthed upper ends of the spring clips; but still allowing it to remain
perpendicularly over them..so that it is readily guided into them when drawn, down;
wards.

page_text: This switch is operated as follows: To complete the circuit all that is required is
to draw down the cylindrical cross bar either by means of the pendant itself being
attached to it or by pulling on a cord provided for the purpose until the cross bar
enters and is grasped by the two pairs of bell mouthed clips. To disconnect the circuit.
the cross bar must be drawn down, a second time until it passes right through the
clips. These will close behind it and on relaxing the tension on the cross bar. it will
be drawn upwards by its spring or other means employed, to its original first position
passing thereto to either side of the pair of clips, on the outside of them.
The connections through these spring clips and cross bar may be made. in various
ways. The bell mouthed entrances of the clips may be formed also so as to afford.a.,
stop of a more or less springy nature tending to keep the cross bar in its second
position with sufficient firmness for the purpose..
In another form of this switch we dispense altogether with one pair of spring, clips.
and in place of the other, pair we make a clip of the required form out of a single
spring forming the free end of this spring, in such manner that the cross bar above
described, can in its first descending movement press it away to one side until the
spring engages with the cross bar in the on, or full contact, position..
A second downward movement of the cross bar sufficient for it to free the lower..
end of the spring will allow the latter to spring back into its original position
which will then be to, the other side of the cross bar and allow the latter. to rise to its
first position up the opposite side of the spring end to that of which it descended.
WM. BROOKES, & SON,
55 & 56, Chancery Lane, London,
Agents, for the said
R. E. B. Crompton and W. A. Kyle.

page_text: A further downward movement of the cross bar sufficient for it to free the lower
end of the spring will allow the latter to spring back into its original position which
will then be to the other side of the cross bar and allow the latter to rise to its first
position up the opposite side of the spring end to that from which it descended.
We use a bell-pull switch arrangement which is so made that a
light and a second pull turns it off again. This is shewn in the drawings.
pull turns on the
Figure 1 is a vertical section of our improved suspending arrangement for electric
lights. Figure 2 is a like view of parts of the same taken at right angles to Figure 1.
Figure 3 is an underside view of the same.
k
The wire
c is the
a is the ceiling or suspending plate. b.is the case enclosing other parts.
face of the hook of the spring d. e is a vibratory spring carrying the projection f
attached to the tube g by the block h. The twin wires shewn as twisted from the
hanging lamp are carried into the tube g.
is electrically connected
through the tube y and block h to the spring e with the rubbing cross piece f. On
pulling the twin wires, the tube g, with the guide piece and spring e slides down,
the pin working in a slot in the outer tube 6. This compresses the spring j. When
the spring e is pulled down the cross piece or projection gears into the grooved face c
which is attached by the spring d, herein shewn and described as a C spring but the
form of spring may be varied, to the block to which one lead is attached. Contact is
thus made between the tube.g to which one of the lamp leads is soldered, and the
block. On repeating the pull the projection or bar pulls out of the groove c¹ in the
faco C, and on letting go the spiral spring j raises e and f, and slides up behind e to
the position shewn in the drawings. The other lamp wire is led up through the top
as shown.
In our provisional specification as filed we have described various alternative
methods other than that herein described of suspension but we have not found these in
practice sufficiently useful to induce us to make any further reference or claim
thereto herein.
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
In an electric light fitting the combination or arrangement and use of parts for
suspending a lamp so that by a pull on the pendant the current may be switched on
and off as set forth.
WM. BROOKES & SON, .
55 & 56, Chancery Lane, London,
Agents for the Applicants.