IMPROVEMENTS IN ELECTRIC- LAMPS "
Year: 1882

page_text: LETTERS PATENT to Andrew Ainslie Common, of Ealing, in the County of
Middlesex, Engineer, for an Invention of "IMPROVEMENTS IN ELECTRIC-
LAMPS
"
PROVISIONAL SPECIFICATION left by the said Andrew Ainslie Common at
the Office of the Commissioners of Patents on the 9th February 1882.
ANDREW AINSLIE COMMON, of Ealing, in the County of Middlesex, Engineer.
"IMPROVEMENTS IN ELECTRIC LAMPS."
This Invention relates to lamps of the arc kind where carbons are used vertically
and the upper carbon holder only inoved.
by the clutch I
I propose to make this holder of steel tube and to get the necessary motion by
means of a core and selenoid with or without a shunt; this core lifts a balanced
lever with a variable axis or fulcrum. The lever lifts the rod by means of a
suitable clutch the finger of which may be made to engage with any part of the
lever within its range, thus altering the lift or leverage.
To prevent the sudden drop of the carbon holder when released
make of it a regulator by filling it with mercury and using a rod and piston, this ·
piston having a valve of platinum to allow a quicker motion up. To prevent the
spilling of the mercury when the lamp is laid down or turned up, I enlarge the
upper part of this tube and provide in the top a sleeve or long collar for the rod to
work through so as to form a trap to prevent any leakage of the mercury.
In lamps where it is desirable to keep the upper part clear I use two or more
light rods to support the upper carbon, bringing these through guides below the
lower carbon and obtain the movements in the above manner.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Andrew Ainslie Common in the Great Seal Patent Office on the
2nd August 1882.
"
_ANDREW AINSLIE COMMON, of Ealing in the County of Middlesex, Engineer.
'IMPROVEMENTS IN ELECTRIC LAMPS."
My Invention consists of certain improvements in electric are lamps or regulators
whereby the number of working parts is greatly reduced and consequently the
liability of the said lamp to get out of order.
These improvements consist in making the working portion which carries the
holder of the upper carbon of steel tube as a combination of strength and lightness,
and to get the necessary lifting motion required for this by means of a core and
solenoid (with or without a shunt); and in order to reduce the available large lift
of the said core in a solenoid to the essentially small lift of the upper carbon
necessary to establish the electric arc I employ the following improved mechanism,
consisting of a plate lever of peculiar construction working on a variable fulcrum
or axis together with a clutch, or sleeve and toe piece, as hereinafter fully
described.
To prevent the too sudden drop of the upper carbon with its holder and steel
tube when released by the clutch or toe piece, I use a governor, either in the form
of a cataract by filling the upper portion of the tube with mercury and using a rod
and piston as hereinafter more fully-described, or-by-means of a train of gear
wheels and pinions the differential motion of which sets a fan in rapid rotation as
in a clock when striking.
A
I show alternative arrangements each for the clutching or gripping gear for
lifting and for working with any desired length of arc. This length being due to
the position of the said clutch or toe piece on the circumference of a circle which
forms part of the said plate lover, but both these arrangements may be considerably
modified.
Figure 1-Sheet 1, of the accompanying two Sheets of Drawing represents the
sectional elevation of my lamp as designed for working where it may be conveniently
suspended.
In Figure 1, A, is a cast metal box inside which, on the bottom, are two vertical
plates B, on which the plate lever C, works, the variable point of contact F, thus
forming the fulcrum or axis; D, is the steel tube carrying on its lower end the
upper carbon holder D', and the upper portion forming a cylinder for the mercury
which acts as a regulator; D is a soft iron core actuated by the solenoid coil E,
(and shunt coil if used); G, is a loose pin to keep the plate lever in position
should the lamp be turned up or become deranged from any other cause; H, is tho
sleeve in which the tube D, is free to revolve (see Fig 2) and to which is connected
by a pin, on which it is free to move, the toe piece J, its outer end resting on the
annular space K, formed on the plate lever C, (see Fig 1). H, and J, form the clutch
for lifting the tube D
Another arrangement of this clutching or gripping and lifting gear is shown at
Figs 5 and 6; L, is a metal ring held in any desired position on the plate
lever C, by the three screws n. This ring L, is provided with two extensions on
its inner circumference (see Fig. 2) which are bent down and stand one on either
side of the too piece J, which can thus be carried round (together with the sleeve H)
to any desired point on the circumference of the annular space formed on the plate
lever C.

page_text: Instead of the said extensions or horns, pins may be fastened to the ring L, or
the annular space K, on the plate lever C, may have holes drilled at certain
intervals (see Fig 4,) in any one of which the outer end of the toe piece J, may
rest, and be confined to that particular position by means of the ring L, sufficient
space however being allowed for the motion it requires.
Adjustable weights are placed on one end of the plate lever C, in order to partly
balance the weight of the solenoid core D', (see Fig 1).
On the metal box A, and above the terminals T, T', lugs or ears are cast through
which the insulated lead wires pass and are firmly fastened thereto. This is to
release the strain due to the pull of the wire which would otherwise come on the
junction at the terminals T, T", rendering the electric circuit liable to be broken.
On the bottom of the sides of the said metal box A, other lugs or ears are cast
(see also Fig 2) to which by means of collars and nuts are securely fastened the
insulated rods N, N', (Fig 1,) carrying at their lower ends the bracket O, (see
also Fig 3.) This bracket is provided with a holder P, (for carrying the lower
carbon) which is part of an adjustable ball joint whereby the lower carbon may be
inclined if required at a slight angle (Fig 1,) so as to exactly meet the upper
carbon and thus obviate the liability of the point of one getting by the point of
the other. This form of joint may also be adapted to either the upper or lower
carbon holder, or both as required.
A suitable arrangement for raising and lowering the globe, as well as for sup-
porting it is shewn in the Drawing (Fig 1). Figure 1 also shews my improved regulator
arrangement; D, is the steel tube plugged at a point sufficiently low to allow for the
travel of the piston Q, due to the motion required for one feed of the upper carbon
as it is consumed; R, is the piston rod, which together with the piston Q, is a fixture;
S, is an enlarged extension of the steel tube D, or cylinder and forms a trap to
prevent any leakage of the mercury when the lamp is laid down or turned up.
A cover U, is screwed to the top of this chamber S, provided in its centro with a
long collar which passes some distance down the chamber and through which the
piston rod works. The object of this long collar is that when the lamp is turned
up or laid down, and the mercury runs from the tube or cylinder into the chamber S,
it shall not reach the point where the hole in the cover through which the piston
passes joins the said chamber, for the aforementioned reason.
V, is a platinum valve.
The piston Qis provided with several small holes as shown in Figure 1 over which
the valve V, rests. The platinum being heavier than the mercury always rests on
the piston. This arrangement is to prevent any sudden drop of the upper carbon
when the steel tube D, is released by the clutch but allows of a comparatively quick
motion of the same upwards. This regulator arrangement is encased by an outer tube
securely fixed to the box A, and surmounted by a cap W, to which the piston rod R,
is attached and which also forms a ring by which the lamp may be suspended.
Figure 2, is a sectional plan of the lamp taken through the line Y, Y.
On Sheet 2, Fig. 7, shows a sectional elevation of my lamp as designed for the
lighting of sheets or in any position when placed on a column or lamp post. For
this purpose the principle and mechanism are the same but the detail is slightly
different. In place of the box A, I substitute a plate (circular from choice) also
marked A, on which the whole of the working parts is mounted. This circular
plate A, is bolted between the top of the post and a case A', which covers in the
mechanism and carries on its summit the globe.
This plate also supports any number of rods A*, (four in this case) Fig 8,
which in turn support at a convenient distance another plate A³. This plate
carries in its centre (Fig. 9) but insulated from it, the lower carbon holder and
makes a tight joint round its edge with the case A', so as to exclude the falling
carbon and other dust from the working parts (Fig. 7.) The upper carbon is
carried in a holder P contained in a bracket O. (Fig. 10) with any number of

page_text: arms (in this case three) and forming a ball joint as described for my other lamp.
To the arms on this bracket O, rods N, N', N, are attached and passing through
holes in the plate A³, are again connected below by a three armed piece A',
(Fig. 11) in the centre of which is firmly fixed the steel tube D, (Fig. 7). The
mechanisin connecting the tube D, to the upper carbon now being on the top of
the said tube I place my regulator at the bottom carrying it into the interior of
the lamp post or column. In this case I much enlarge my piston Q, so that its
floating power may assist in raising the extra weight of the bracket O, guide
rods N, N', N2, and three armed piece A*.
The netion of my lamp when at work is as follows. The carbons being together
(Sheet 1, Fig. 1.) and the circuit thus complete, the current enters the lamp by the
terminal T, passing at once through the coil of wire E, to some portion of the
framework of the lamp and thence through the tube D, upper and lower carbons,
bracket O, and rod N, to the terminal 1, from which it passes to the next lamp
or back to the dynamo machine as the case may be.
The attractive influence of the coil of wire on the soft iron solenoid core or
electro-magnet D2; due to the passage of the electric current, immediately lifts or
sucks it up, raises one end of, and pivots on its fulcrum F, the plate lover C. The
portion of this plate lever forming the annular space K, carries with it the outer
end of the too piece J, which, with its other end and the aid of the sleeve H,
immediately grips firmly the tube D. The further lift of the plate lever C, (the
motion of which at the point K, continually increases, in proportion to that of the
solenoid core D², owing to the fulcrum F, gradually receding farther from the pull
exerted by the said core) now carries with it the tube D, and upper carbon, so
establishing the electric arc. Immediately the increased resistance of this arc, due
to the burning away of the carbons weakens the attractive influence or lifting
-power of the coil E, the core D³, lowers, allows the plate lever C, to tilt back, and
releases the grip of the toe piece J, thus allowing-the-tube-D, carrying_the_upper_
carbon to drop, which by the resistance of the mercury to the passage of the piston
through it, it does gently thus again establishing the arc at its proper length,
together with the attractive power of the coil E, which lifts the solenoid core D³,
as before.
Having now described and ascertained the naturo of my Invention and in what
manner the same is or may be performed, I would have it understood that I do not
limit myself to the precise details herein before described and illustrated on the
accompanying Sheets of Drawing, as such may be varied while retaining the
essential features of my improvements and that what
I claim as of my Invention and secured to me by the hereinbefore in part
recited Letters Patent is:-
Firstly. In an electric arc lamp, the feed movement and regulating consisting of
the combination of the plate lever C, having the ring L, attached, with the toe
piece J, and solenoid E, substantially as herein before described and as shown
Figures 1, 2, 3, 7, and 8, of the accompanying Sheet of Drawing; and also the
modifications thereof substantially as herein before described and as shown
Figures 4, 5, and 6, of the Drawings.
Secondly. In an electric arc lamp, the balanced plate lever C, in combination
with the variable fulcrum F, substantially as hereinbefore described and as shown
Figs 1, and 7, of the Drawings and for the purposes set forth.
Thirdly. In an electric arc lamp, making the toe piece J, adjustable for the
purpose of varying and determining the lift of the moveable carbon substantially
as hereinbefore described and as shown Figs 1, 2, 7, and 8, of the Drawings;
and also the modification thereof substantially as shown in Fig 4.
Fourthly. In an electric arc lamp, the combination of the platinum valve V
with the mercurial regulator substantially as hereinbefore described and shown
Figs 1 and 7, of the Drawings and for the purpose specified.

page_text: Fifthly. The construction and general combination of parts forming electric are
lamps substantially as hereinbefore described and illustrated Figures 7, 8, 9, 10
and 11, of the accompanying Drawings.
In witness whereof I the said Andrew Ainslie Common, have hereunto set
my hand and seal, this. Thirty first day of July in the year of our Lord
One thousand eight hundred and eighty two.
ANDREW AINSLIE COMMON. (L.S.)