IMPROVEMENTS IN ELECTRIC ARC LAMPS
Year: 1882

page_text: LETTERS PATENT to William Buller Fullerton Elphinstone Baron Elphinstone
of Carberry Tower, Musselburgh, North Britain; Charles Wilson Vincent of
Holloway in the County of Middlesex; and John Cottrell of Brixton in the
County of Surrey for an Invention of "IMPROVEMENTS IN ELECTRIC ARC
LAMPS"
PROVISIONAL SPECIFICATION left by the said William Buller Fullerton
Elphinstone, Charles Wilson Vincent and John Cottrell at the Office of the
Commissioners of Patents on the 18th November 1882.
WILLIAM BULLER FULLERTON ELPHINSTONE, Baron ELPHINSTONE of Carberry
Tower, Musselburgh North Britain, CHARLES WILSON VINCENT of Holloway in the
County of Middlesex, and JOHN COTTRELL of Brixton in the County of Surrey
"IMPROVEMENTS IN ELECTRIC ARC LAMPS."
The chief object of this invention is to produce a simple construction of arc
lamp (suitable for both pendent and standard lamps) which may be regulated with
the greatest delicacy, and thereby ensure the maintainence of a steady light
unaffected by the feed of the carbon or carbons.
Supposing our invention to be applied to the construction of a suspension lamp
we attach to a suspension frame or hoop a metal box or cylinder which we fit with
a short concertina bellows.
The bottom of this bellows which is open at its centre rests upon a solenoid, also
contained in the box or cylinder, and fitted to the under face of the top of the
bellows is a core for entering the solenoid.
A light spring within the bellows serves to hold the bellows extended and to
the upper end of the bellows is fitted the holder for receiving the lower or negative
carbon.
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The core is pierced with a central hole, and pendent in the core is a rod which
carries at its lower end a small conical valve.
A seat for this valve is made in the bottom of the box or cylinder which carries
the solenoid and bellows, and opening to this seat is a passage made in the

page_text: suspension frame or hoop leading up one side only of the same to a second bellows
pendent from the upper part of this frame or hoop.
The valve rod is connected by a light spring with the solenoid core, for the
double purpose of holding the valve to its seat when the core is drawn down by
the action of the solenoid, and of lifting the valve clear of its seat when the core
yields to the upward pressure of the bellows spring.
Pendent from the upper bellows is the upper or positive carbon holder, which
holder is steadied in its descent by sliding through a guide tube forming part of
the suspension frame.
Supposing now the carbons to be in contact, and a current to be passed into the
lamp, the current will flow down through the carbons to the metal box or cylinder
containing the lower bellows. This box is in metallic connection with the solenoid
which it contains, but insulated from say the solid half of the hoop or suspension
frame with which the solenoid is in metallic connection.
The descending current passing from the lower carbon holder to the box will
enter the solenoid and cause the core to be attracted, whereby the lower carbon
will be drawn down to form the arc. After traversing the solenoid the current
will pass up the insulated portion of the suspension hoop or frame, to the return
wire.
As the arc lengthens by the consumption of the carbons the strength of the
current will be proportionally weakened, and the attraction of the solenoid will
consequently lessen. The spring of the lower bellows will now force up the lower
carbon and restore the arc. This action will continue until the lower carbon has
attained its maximum height, at which time the are being unduly lengthened, and
the solenoid weakened, the core will lift the valve from its seat and allow air from
the box or cylinder to pass up through the air passage in the suspension hoop or
frame in a regulated amount into the upper bellows thereby providing for the
dropping of the upper carbon to restore the arc.
Simultaneously with this descent of the upper carbon the current will be
strengthened. The solenoid will then draw down the core, together with the lower
carbon, and cause the valve to be seated.
For supplying air to the solenoid box or chamber its bottom is pierced and this
opening is governed preferably by a small screw plug.
When applying the invention to a lamp in which the light is required to be
maintained at a uniform level we employ a pair of bellows for giving the feeding
motion to the carbons.
These bellows we mount in boxes or cylinders (which are closed at their lower
ends) upon pairs of rocking levers having their fulcra upon standards carried by a
base plate.
From one bellows will stand up the lower carbon holder, and from the other will
rise a standard carrying the other carbon holder. These bellows are connected
together by one of the rocking levers which is made hollow for the purpose of
allowing a flow of air from one bellows to the other which flow is regulated by a
cock or valve which is set in action by the rocking of the lever.
The two bellows are so proportioned that the compression of the one which
carries the positive carbon shall displace only so much air as will serve to raise
the bellows with its negative carbon to the determined height.
Pendent from the cylinder carrying the negative carbon is a core which enters a
solenoid fitted to the base of the lamp and connected with the bottom of the other
cylinder is a coiled spring the tension of which is regulated by an adjustable lever
carried on the base plate.
This spring acts like the spring in the lower bellows of the first arrangement,
and serves to counteract up to a certain point the attraction.of the solenoid.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by,
the said William Buller Fullerton Elphinstone, Charles Wilson Vincent.
and John Cottrell in the Great Seal Patent Office on the 18th May 1883.
WILLIAM BULLER FULLERTON ELPHINSTONE Baron ELPHINSTONE of Carberry
Tower Musselburgh North Britain CHARLES WILSON VINCENT of Holloway in the
County of Middlesex and JOHN COTTRELL of Brixton in the County of Surrey
IMPROVEMENTS IN ELECTRIC ARC LAMPS "
"
The chief object of this Invention is.to simplify the construction of arc lamps
whether pendant or standard lamps, and enable them to be regulated with the
greatest delicacy, whereby a steady light unaffected by the feed of the carbon or
carbons will be ensured.
To this end we adapt to the lamp an arrangement of pneumatic apparatus which
aided by the action of a solenoid will control the movement of the carbons as
desired.
In the accompanying drawings Fig 1 shews in front elevation (partly in
section) a pendent arc lamp constructed according to our Invention.
A A is the metal suspension frame carrying at its lower end a solenoid B-B'
is the hollow bobbin of the solenoid which is closed at bottom by a thick plate of
metal B' to which the rods of the suspension frame are secured by clamping screws
The plate B is pierced with a fine hole b for a purpose to be presently explained-
In the centre of this plate a seat b' is formed for a small conical valve and leading
horizontally from this seat to one of the rods forming the suspension frame is a
passage b². This rod is hollow throughout its length and it is insulated from the
plate B².
Made fast to the bobbin of the solenoid is a cylindrical case C which forms a
guide for the soft iron core D of the solenoid. To the upper end of this core is
attached the lower carbon holder E and a tendency is given to it to stand at its
highest elevation by means of a light spring & surrounding the stem of the core D
Attached to this stem of the core and fitting loosely in the box C is a disc which
forms the top end of a short bellows C¹ of the concertina type the lower edge of
which is made fast to the bobbin of the solenoid
Pendent from the core D is a loose rod d' carrying at its lower end a conical
valve d² (formed of nonconducting material) which is held to its seat b¹ by a light
spring surrounding the valve rod and bearing against the bottom of the core
and the top of the valve: this will admit of the core moving vertically to a limited
extent without affecting the valve which is attached thereto
The passage b' is brought, into communication through the hollow suspension
rod A with a second bellows F pendent from the upper part of the frame and
carrying the upper carbon holder G.-This bellows F is made fast to the underside
of a plate F¹ which is attached by clamping screws to the rods of the suspension
frame but is insulated therefrom.-A passage f is drilled in this plate F¹ to bring
the bellows into communication with the hollow rod.
Attached to the underside of the plate F¹ by screws, is a cylindrical metallic
F which encloses the bellows F and forms at its lower end a guide for the upper
carbon holder G to slide in freely.
The electric current passes to the lamp by the wire H which is clamped to the
plate F and from this plate it passes through the carbons to the solenoid. This
solenoid is brought by an extension B* of its wire into electrical connection with
the lower end of the insulated hollow rod A of the pendent frame, the upper end
of which is in connection with the return wire of the circuit
:

page_text: Supposing now the upper bellows F to be wholly or partially collapsed and the
lower bellows to be expanded the carbons being in contact; on passing an electric
current into the lamp the current will flow down through the carbons to the metal
box or cylinder C which contains the bellows C¹ of the lower carbon holder E and
is in metallic connection with the solenoid B.
The descending current passing from the lower carbon holder to the box will
enter the solenoid and cause the core D to be attracted, whereby the lower carbon
will be drawn down to form the arc After traversing the solenoid the current
will pass up the insulated rod A of the suspension frame to the return wire and so
complete the circuit
As the arc lengthens by the consumption of the carbons the strength of the
current will be proportionately weakened and the attraction of the solenoid will
consequently lessen. On this occurring the spring d will force up the lower carbon
and restore the arc-This action will continue until the lower carbon has attained
its maximum height-So soon however as the arc by the burning away of the
carbons becomes unduly lengthened and the solenoid consequently weakened the
core D will lift the valve d from its seat and allow air from the box or cylinder C
to pass along the air passage b' up the hollow rod A in a regulated amount into
the upper bellows F.-This admission of additional air to the bellows F will
cause the expansion of the bellows and allow for the dropping of the upper carbon
to restore the arc
Simultaneously with this descent of the upper carbon the current will be
strengthened The solenoid will then draw down the core D together with the
lower carbon which it carries and cause the valve to be seated.
For supplying air to the solenoid box or chamber its bottom is pierced as at b
and this opening may, if thought desirable be governed by a sinall screw plug.
When applying the invention to a lamp in which the light is required to be
maintained at a uniform level, we employ a pair of bellows for giving the feeding
motion to both-carbons arranging the same as shewn in the partial sectional
elevation Fig 2
In this figure A is the bellows which serves to carry the positive carbon holder A¹
it being furnished with a vertical rod to which an arm adjustable vertically and
horizontally and carrying the holder is attached
B is the bellows on which the negative carbon holder B¹ is mounted and to the
bottom of this bellows is fitted a soft iron core C which plays in the solenoid C¹ as
in the first arrangement
The bellows A is enclosed in a cylinder of vulcanite A² the closed bottom of
which forms the bottom of the bellows Similarly the bellows B is enclosed in a
vulcanite cylinder B³ the closed bottom of which forms the bottom of the bellows B.--
Jointed to the bottoms of the two bellows is a hollow rocking beam D centred at D'
and working upon a fixed valve which opens a communication between the bellows
and cuts off that communication as the hollow beam is rocked by the expansion
and contraction of the bellows.
D is a second rocking beam attached to the upper ends of the vulcanite
cylinders, and serving to ensure the maintenance of the parallel motion of the
cylinders as they rise and fall-The pivots of these beams are carried by a vertical
partition forming part of a box E E attached to the base of the lamp and enclosing
the pneumatic apparatus, and the parts in immediate connection therewith.-In
the top of this box two insulated metallic guides e e¹ are fitted for the purpose of
steadying the vertical movements of the carbon holders A' and B' respectively, and
making metallic contact therewith.
The bellows A and B are so proportioned, both with respect to their capacity
and form, that the expansion of the one due to the contraction of the other shall
bear the same proportion as the varying rates of combustion of the two carbons
When starting the lamp the bellows A will be expanded and the bellows B
collapsed. the compression of the bellows A consequent upon the feed of the positive
carbon will displace only so much air as will serve to raise the bellows B with its

page_text: negative carbon to the determined height for maintaining the are at the desired
level
Connected with the bottom of the cylinder A' is a coiled spring a which is
attached to a bell crank lever a' fulcrumed on the lamp base and borne against by
an adjusting screw a² which serves to regulate the tension of the spring
This spring acts like the spring d in the lower bellows of the first described
arrangement and serves to counteract up to a certain point the attraction of the
Bolenoid which by attracting the pendent core O snatches down the negative carbon
to form the arc
The lamp is brought into circuit by means of the terminals e³ ³ attached to the
case E-The terminal E' connects with the solenoid from which a wire is led to the
insulated metal guide e, and the terminal e³ is similarly connected with the insulated
metal guide e. Supposing now a current of electricity is admitted to the lamp by
the terminal e, it will pass through the solenoid and thence by the metallic guide s
to the positive carbon holder: from this the current will pass through the carbons
to the metal guide e¹, thence to the terminal e³ and so back to the source of supply-
So soon as this circuit is established the solenoid will draw down the core C and
establish the arc-As however the current becomes weakened by the combustion
of the carbons the coiled spring a attached to the cylinder A³ will cause the hollow
beam to rock and open an air passage between the two bellows
The pressure on the bellows A caused by the pendent carbon and its supports
will force air out of the bellows A into the bellows B and thereby cause the lower
carbon to approach the descending upper carbon.-On this being effected to the
desired extent the increased strength of the current consequent thereon will cause
the solenoid to draw down the core C and with it the cylinder B' which will rock
the hollow beam D and thereby close the communication between the bellows A
and B.
By a repetition of these actions a slow and regular feed of the carbons will
result, the position of the arc being maintained at a uniform level.
Having now explained the nature of our Invention of "Improvements in Electric
Arc Lamps" and explained the manner of carrying the same into effect we wish it
to be understood that under the above in part recited Letters Patent We claim:-
First: The adaptation to arc lamps of the arrangement of pneumatic apparatus in
combination with a solenoid as described with reference to Fig: 1 of the drawings
for controlling the movement of the carbons and maintaining the arc.
Second: The adaptation to are lamps in which the arc is required to be main-
tained at a uniform level, of the arrangement of pneumatic apparatus in combination
with a solenoid as described with reference to Fig: 2 of the drawings for controlling
the feed of the carbons.
In witness whereof I the said Charles Wilson Vincent have hereunto set my
hand and seal the seventeenth day of May in the year of our Lord One
thousand eight hundred and eighty three.