IMPROVEMENTS IN ELECTRIC LAMPS
Year: 1882

page_text: LETTERS PATENT to Joseph Devonport Finney Andrews of Sauchiehall Street
Glasgow in the County of Lanark for an invention of "IMPROVEMENTS IN
ELECTRIC LAMPS,”
PROVISIONAL SPECIFICATION left by the said Joseph Devonport Finney
Andrews at the Office of the Commissioners of Patents on the 18th March
1882.
JOSEPH DEVONPORT FINNEY ANDREWS of Sauchiehall Street Glasgow in the
County of Lanark "IMPROVEMENTS IN ELECTRIC LAMPS "
In several kinds of electric lamps, the carbon rod or its holder is supported by a
clutch which consists of a plate with a hole through it of sufficient size to let the
carbon or its holder slip through when its plane is perpendicular or nearly so to the
axis of the rod, but which prevents the rod from slipping through the hole when
the plate is moved to an attitude oblique to the axis. Usually a clutch plate of
this kind is attached to the armature of a regulating electro-magnet by which it is
worked, and it is difficult to adjust the parts so as to operate with that delicacy
which is required for proper regulation of the are consistently with due feed of
the carbons. In the Specification to my Patent No 1526 of 1881 I described
several forms of clutches arranged so as to obtain greater delicacy of action;
according to my present invention I effect this by detaching the clutch from the
armature that works it so that the armature that works it so that the armature
is capable of giving a certain amount of regulation without working the
clutch, and works it only when feed of the carbon is required. For this
purpose I arrange an electric lamp as follows. The upper carbon is attached
to an arm projecting from a vertical rod which is free to slide downwards but
which is prevented from so sliding by the friction or hold of a clutch acted
on by a spring. The lower carbon is supported on the core of a solenoid
coil which is of high resistance and is in a shunt or by-pass circuit connecting
the lamp circuit. This core is linked to a lever which has an arm that, when
the lever moves beyond a certain distance, acts on the clutch releasing it.
When the lamp is put in circuit, if the carbons should be apart, the current

page_text: passing through the shunt excites the solenoid so that its core is attracted upwards
raising the lower carbon and releasing the upper carbon so that the carbons meet.
The current then passing freely through the carbons, the solenoid becomes so
weakened that its core with the lower carbon descends and the clutch holds the
upper carbon;
the carbons being thus separated the arc is started, and is afterwards
regulated by the up and down movement of the solenoid core and lower carbon.
When, however, owing to consumption of the carbons, the core is caused to
ascend beyond a certain point, its lever releases the clutch permitting the upper
carbon to descend a little, and thereupon the regulating movement continues until
a fresh feed is required. In order to prevent sudden downward movement of the
upper carbon when it is released, its movement is controlled by a dashpot, which
may be effected by making the rod that sustains the upper carbon tubular charging
it with liquid and placing in it a stationary piston which nearly fits it or which
fits it and has a small hole for passage of the liquid. Or instead of the dashpot a
second clutch may be employed worked by a third arm of the core lever, the arms
being so arranged that the one clutch becomes released just before the other. Thus
the clutch first released being of the oblique plate kind, and the other being a
friction clutch, the carbon can descend slowly when the first is released, but cannot
descend rapidly unless both are released. When I employ a clutch of the
oblique plate kind, I make the plate of the form of U, with two limbs embracing
the rod and a pin passed through them beyond the rod. By taking out this
pin, the clutch can at any time be taken off the rod and cleaned or otherwise
adjusted.
In order to provide for a succession of carbons in a lamp, so that when one pair
is consumed another pair may immediately take its place, I arrange a number of
carbons side by side in compartments of a box or case. The lower carbons are in
one box, each pressed up by a spring against a shoulder at the top of its compart-
ment so that the point of the carbon projects above the mouth of the compartiment.
The upper carbons are also in a box from which their ends project downwards
between two rollers which are pressed towards each other by suitable springs and
are worked by regulating apparatus of any known kind applied to the feed and
regulation of carbons held between rollers. The rollers are conical so that only the
first carbon of the series is pressed between them, the other carbons being free from
pressure. The current entering by the rollers passes only through the first carbon,
the others being out of contact. When however the first carbon is consumed, then
the rollers being no longer kept so far apart, approach so as to grasp the second.
carbon, which in its turn becomes consumed. And thus after each carbon is con-
sumed, the next carbon in order is brought within the grasp of the rollers and
becomes the acting carbon, until all are consumed.
For incandescent lamps, instead of employing a fibre I employ a thin plate of 4
carbon having one of its edges clamped between the limbs of a bent platinum wire,
and its opposite edge similarly clamped, both wires passing hermetically sealed
through the bottom of the exhausted glass globe or bulb in which the carbon is
contained. The carbon plate may be divided into several sections, all of them held
at one end in a wire clamp, but at their other ends held in separate wire clamps. 4
The wires of these separate clamps may be connected in circuit separately, or
any two or three or other number of them may be connected in circuit at one time
so that any one, two three or other number of the sections of the carbon plate can
be rendered incandescent, and thus the power of the lamp can be varied.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Joseph Devonport Finney Andrews in the Great Seal Patent
Office on the 16th September 1882.
JOSEPH DEVONPORT FINNEY ANDREWS of Sauchiehall Street Glasgow in the
County of Lanark "IMPROVEMENTS IN ELECTRIC LAMPS "
In several kinds of electric lamps, the carbon rod or its holder is supported by a
clutch which consists of a plate with a hole through it of sufficient size to let the
carbon or its holder slip through it when its plane is perpendicular or nearly so to
the axis of the rod bat which prevents the rod from slipping through the hole when
the plate is moved to an attitude oblique to the axis. Usually a clutch plate of
this kind is attached to the armature of a regulating electro-magnet by which it is
worked, and it is difficult to adjust the parts so as to operate with that delicacy
which is required for proper regulation of the are consistently with due feed of the
carbons. In the Specification to my Patent No 1526 of 1881 I described several
forms of clutches arranged so as to obtain great delicacy of action; according to my
present invention I effect this by detaching the clutch from the armature that works
it so that the armature is capable of giving a certain amount of regulation without
working the clutch and works it only when feed of the carbon is required. For
this purpose I arrange an electric lamp as shewn in side view by Fig. 1 of the
accompanying drawings. The upper carbon A is attached to an arm B projecting
from a vertical rod C which is free to slide downwards but which is prevented from
sliding by the frictional bold of a spring rubber D. The lower carbon E is supported
on the core of a solenoid F whose coil of high resistance is in a shunt or by-pass to
the lamp circuit. The core is linked to a lever G which when the core rises beyond
a certain point acts on the rubber D releasing it. When the lamp is put in circuit
if the carbons should be apart the current passing through the shunt excites the
solenoid so that its core is attracted upwards raising the lower carbon and releasing
the upper carbon so that the carbons meet. The current then passing freely through
the carbons, the solenoid becomes so weakened that its core with the lower carbon
descends and the rubber D holds the upper carbon, the carbons being thus separated
the arc is started, and is afterwards regulated by the up and down movements of
the solenoid core and the lower carbon. When, however, owing to consumption
of the carbons the core is caused to ascend beyond a certain point its lever releases
the rubber D permitting the upper carbon to descend a little and thereupon the
regulating movement continues until a fresh feed is required. In order to prevent
sudden downward movement of the upper carbon when it is released its movement
is controlled by a dash pot, which is effected by making the rod C tubular and
charging it with liquid and placing within it a piston H that nearly fits the tube
or has a small hole through it and is held by a rod attaching it to the upper frame
of the lamp. Instead of thus employing a dash pot a second clutch may be employed
as shewn in the part side view Fig. 2 and the plan of the clutch Fig. 3. This
clutch K consists of a plate in form of a yoke embracing the rod C and having a
cross pin by which it is pivotted to the framing of the lamp. The lever G has a
short arm which when the core ascends bears on the clutch plate K bringing it
towards a horizontal attitude and so causing it to release its hold of the rod C, and
when the core ascends still farther the upright arm of the lever G releases the
rubber D. Thus the friction of D can be adjusted so that the upper carbon
descends slowly when K is released, but cannot descend rapidly unless K and D
are both released. By taking out the cross pin of K, the clutch can be removed,
cleaned or adjusted.

page_text: In order to provide for a succession of carbons in a lamp, so that when one pair
is consumed another pair may immediately take its place, I employ the arrangement
shewn in side view at Fig. 4, in front view at Fig. 5 and in plan at Fig. 6 and
Fig. 6. The lower carbons E are in a box, each pressed upwards by a spring
against a slight shoulder at the top of its compartment so that the point of the
carbon projects above the mouth of the box. The upper carbons A. are in
compartments of a box from which their ends project downwards between two
rollers L L which are pressed towards each other by springs and are worked by
regulating apparatus of any known kind applied to the feed and regulation of
carbons held between rollers. The rollers L are conical as shewn in Fig 6 or have
their axes inclined to one another as in Fig 60 so that only the first carbon A of
the row is pressed between them, the other carbons A being free and simply resting
on the corresponding lower carbons E. The current entering by the rollers passes
only through the first carbon, the others being out of contact. When however the
first carbon is consumed, then the rollers being no longer kept so far apart, approach
so as to grasp the second carbon, which in its turn becomes consumed. And thus
after each carbon is consumed the next carbon in order is brought within the grasp
of the rollers and becomes the acting carbon, until all are consumed.
For incandescent lamps instead of employing a fibre I employ a thin plate of
carbon having one of its edges clamped between the limbs of a bent platinum wire,
and its opposite edge similarly clamped as shewn in the side view Fig. 7 and edge
view Fig. 8, where M is the thin plate of carbon held at its edges clamped between
the bent wires N O. These wires extend down and are hermetically sealed through
the glass of the exhausted globe or bulb P. The carbon plate may be divided into
several sections as shewn in Fig. 9 and marked M¹ M³ M³. At one edge these are
all held in the one wire clamp N at the other edge each is held in a separate
clamp 01 02 03 respectively. By means of a metallic plug Q passed through their
eyes two or three of the wires 01 02 03 can be connected so that several of the
carbon segments can be rendered incandescent, the power of the lamp being thus
varied.
Having thus described the nature of my invention and in what manner the same
is to be performed, I claim in respect of electric lamps :-
First. Regulating the feed and distance of the carbons by means of a plate clutch
for the holder of the upper carbon operated in conjunctoin with a friction brako by
a solenoid core carrying the lower carbon, substantially as herein described with
reference to Figs. 2 and 3.
Second. Providing for a succession of carbons by apparatus arranged substantially
as described with reference to Figs. 4, 5, 6 and 6ª.
Third. The use in an incandescent electric lamp of a thin plate of carbon clamped
at opposite edges between loops of the conducting wires, substantially as hercin
described with reference to Figs. 7, 8 and 9.
In witness whereof I the said Joseph Devonport Finney Andrews have
hereunto set my hand and seal this Fourteenth day of September in the
year of our Lord One thousand eight hundred and eighty-two.