Improvements in Arc Lamps.
Year: 1897

page_text: Improvements in Arc Lamps.
We, WILLIAM JAMES DAVY and GEORGE THOMAS-DAVIES, both of Horsell Road
Works, Highbury, in the County of London, Engineers, do hereby declare the
nature of this invention to be as follows:-
This invention for improvements in arc lamps relates more particularly to
enclosed arc lamps and has for its principal objects to reduce the enclosed space
so that it does not include the regulating bobbin or solenoid or dash pot that can be
ventilated, to provide an improved means for counterbalancing the weight of the
solenoid core, to improve the electric connections to the carbon, to construct the
chamber containing the regulating mechanism so that it can be more readily got
at without dismantling the lamp and generally to simplify the frame work of the
lamp.
In carrying out this invention as applied to an enclosed are lamp in which the
lower carbon is fixed, the parts are all supported from a central fixed tube. The
cylinder of the dash pot is loose within the top part of the fixed tube and is fixed
at its upper end to a cord that passes over two guide pulleys mounted on the fixed
tube and that has its ends fixed to an annular weight surrounding the fixed tube.
The guide pulleys are mounted between two plates passed through a rectangular
hole in the upper part of the fixed tube just above the dash pot cylinder and are
secured by screws that also serve as supports for the sleeves on which the pulleys
rotate. The piston of the dash pot is pivoted to a depending link or tube fixed
to the fixed tube by a bolt or pin.
The cylinder of the dash pot is connected by a link or tube having slots for the
passage of the piston fixing pin to a cross head guided in slots in the fixed tube.
The cross head is connected by links outside the fixed cylinder to the annular
core of the regulating solenoid surrounding the fixed tube. The cross head is also
connected by a rod passing through a plug secured in the fixed tube and closing it,
to a conical plug screwed cone upwards in the upper end of a guide tube sliding in
the fixed tube and serving as the guide tube for the upper carbon holder. Balls
placed within the fixed tube bear against the fixed tube and the conical end of the
uide tube and make a good travelling electric contact. For a similar reason the
upper end of the carbon holder is closed by a conical plug and balls make contact
between the plug and guide tube. This guide tube being connected to the cross
head moves with the core and is connected at its lower end to the brake or regu-
lating mechanism. The lower end of the fixed tube is screwed into the upper
end of the chamber enclosing the regulating mechanism and the lower end of the
chamber is closed by a removable plug having a hole for the passage of the carbon.
The lower carbon holder is carried by two side rods from a flange on the lower
end of the chamber. The glass enclosing bell is forced against an asbestos washer
held in a groove in the removable plug or bottom of the mechanism chamber.
The carbon holder guide tube just projects through the fixed tube into the
mechanism chamber and has fixed on its lower end a collar or clip by which the
regulating mechanism is operated.

page_text: The contact cones against which the balls bear must be sufficiently obtuse to
prevent the balls wedging. A suitable angle is 90 degrees. Suitable holes are
provided in the fixed tube for ventilation.
Dat the 95th dov of Vacomber 1897
WHEATLEY & MACKENZIE,
40, Chancery Lane, London, W.C.,
Agents.
Improvements in Arc Lamps.
We WILLIAM JAMES DAVY and GEORGE THOMAS-DAVIES, both of Horsell Road
Works, Highbury, in the County of London, Engineers, do hereby declare the
nature of our said invention and in what manner the same is to be performed, to
be particularly described and ascertained in and by the following statement:-
This invention for improvements in are lamps relates more particularly to
enclosed arc lamps and has for its principal objects to reduce the enclosed space
so that it does not include the regulating bobbin or solenoid or dash pot that can be
ventilated, to provide an improved means for counterbalancing the weight of the
solenoid core, to improve the electric connections to the car, to construct the
chamber containing the regulating mechanism so that it can be more readily got
at without dismantling the lamp and generally to simplify the frame work of the
lamp.
The
In carrying out this invention as applied to an enclosed are lamp in which the
lower carbon is fixed, the parts are all supported from a central fixed tube.
cylinder of the dash pot is loose within the top part of the fixed tube and is fixed
at its upper end to a cord that passes over two guide pulleys mounted on the fixed
tube and that has its ends fixed to an annular weight surrounding the fixed tube.
The guide pulleys are mounted between two plates passed through a rectangular
hole in the upper part of the fixed tube just above the dash pot cylinder and are
secured by screws that also serve as supports for the sleeves on which the pulleys
rotate. The piston of the dash pot is pivoted to a depending link or tube fixed
to the fixed tube by a bolt or pin.
core
The cylinder of the dash put is connected by a link or tube having slots for the
passage of the piston fixing pin to a cross head guided in slots in the fixed tube.
The cross head is connected by links outside the fixed cylinder to the
of the regulating solenoid. The Cross head is also connected by
a rod passing through a plug secured in the fixed tube and closing it,
to a conical plug screwed cone upwards in the upper end of a guide tube sliding in
the fixed tube and serving as the guide tube for the upper carbon holder. Balls
placed within the fixed tube bear against the fixed tube and the conical end of the
guide tube and make a good travelling electric contact. For a similar reason the
upper end of the carbon holder is closed by a conical plug and balls make contact
between the plug and guide tube. This guide tube being connected to the cross
head moves with the core and is connected at its lower end to the brake or regu-
lating mechanism. The lower end of the fixed tube is screwed into the upper
end of the chamber enclosing the regulating mechanism and the lower end of the
chamber is closed by a removable plug having a hole for the passage of the carbon.
The lower carbon holder is carried by two side rods from a flange on the lower
end of the chamber. The glass enclosing bell is forced against an asbestos washer
held in a groove in the removable plug or bottom of the mechanism chamber.
The carbon holder guide tube just projects through the fixed tube into the

page_text: mechanism chamber and has fixed on its lower end a collar or clip by which the
regulating mechanism is operated.
The contact cones against which the balls bear must be sufficiently obtuse to
prevent the balls wedging. A suitable angle is 90 degrees. Suitable holes are
provided in the fixed tube for ventilation.
In this lamp the enclosure is obtained without the aid of the outer globe so that
the capacity of the chamber is small and by the use of a sliding or similar joint,
reduced to its very smallest dimensions so that practically no air nor gas can
diffuse or pass.
In the accompanying sheet of illustrative drawings:-Figs. 1 and 2 are sectional
elevations at right angles to one another of an enclosed arc lamp constructed
according to this invention. Fig. 3 is a plan of the top of the lamp Fig. 4 is a
sectional plan through the controlling bobbins. Fig. 5 is a plan of the bottom
yoke, Fig. 6 shows a slight modification of the mechanism chamber. Figs. 7 and 8
show wedge shaped contact pieces.
The frame of the lamp comprises the central tube a and the upper disc b rigidly
secured to the lower end of the tube a and forming the top of the chamber con-
taining the regulating mechanism. The cylindrical case e closed at its lower end
is screwed into the flange of the disc and the bottom yoke f is carried from the
bottom of the case by the yoke rods f. The top of the tube is closed by an
insulating plug having metal caps on its ends. The lower end screws into the
tube a.
On the upper end is screwed the dome. The plug is fixed in the
tube and in the dome by screws passing through the tube or dome and into
the plug. The ornamental easing rests on an insulating plug e.
"
Near the top of the tube a is a rectangular hole through which are passed
plates carrying pulleys Fitting within the tube a below the plates is a
dash pot cylinder i fixed to the centre of a cord passing over the pulleys and
connected to a disc sliding on the central tube a. The piston of the dash pot
is fixed by the pin to the tube a. The cylinder is connected by the side
pieces and pin to the link pivotted to a cap piece fixed in and closing the
upper end of the controlling tubes that fits freely within the tube a and descends
into the case (. The link slides through a hole in the plug a closing the tube a.
The tubes is fitted with a balance weight or damper disc 2 working within
the case and assisting the dash pot action. The core of the series bobbins g
is secured to the boss of the controlling disc and the core of the shunt
bobbins is secured to the controlling disc by the links /P.
The upper carbon holder slides in the controlling tubes and has its upper
end coned. Balls are placed in the tubes and bear on the cone and the
tubes and make a good contact. The upper carbon m passes between two jaws an¹
fixed respectively between the pair links, The links and n³ and
also and are pivotted together at their meeting ends and are connected by
the links to the lower end of the tube s. Normally the jaws rest on a stop
at the bottom of the case c.
The lower carbon holder screws or fits into the lower end of the enclosing
transparent bell and the whole rests on a spring fitting in a recess or hole in
the stud screwing into a cross bar fitting in notches or trunnions in the bottom
yoke f. The cross piece f can be lifted out of the yoke f. The stud² also
carries the nut for securing the usual globe y in position.
r is the resistance
coil, r¹µª outer and inner domes respectively held together by a nut ³.
The current enters the lamp by the positive terminal d, passes then through
choke or resistance to the fuse terminal fuse fuse terminal, terminal b¹.
plate b, tubes a, a, carbons, yoke, insulated terminal 3, the series coil y. insulated
terminal 62, to the main terminal . The shunt coils are connected directly across
the terminals d d.
The carbons being in contact the upper carbon resting on the lower by its own
weight, on the passage of the current through the series solenoids g. the core his
drawn down and consequently the tube is drawn up and first raises the

page_text: links ¹³ off the stop plate and then causes the jaws to grip the carbon and
raise it and strike the are. As the are lengthens due to the burning away,
gradually the grip device is lowered onto the stop plate and the jaws relax their
hold on the carbon and a continuous and steady feed is obtained by the upper
carbon slowly descending through the jaws.
P
the
The spaces open to the are are thus the chamber enclosed by the bell
chamber enclosed by the casing, and the tube s. Any excessive pressure of gases
accumulating escapes through the mouth of the bell, the spring of acting as a
relief.
To renew the carbons, the screw o³ is slackened to remove the globe y, the stud
is then unscrewed out of the cross piece f until the cross piece can be raised out
of its recessed or trunnion bearings in the yoke f and then removed with the bell
and lower carbon-holder through the yoke f, the top carbon and holder following
by its weight. The top carbon is then removed and inserted in the lower carbon
holder and a fresh carbon placed in the upper holder when the bell and lower
carbon are placed in position forcing upwards the upper carbon holder to its upper
position. The upper edge of the bell rests against an asbestos washer and by
gently screwing up the stud the bell is forced against the asbestos the spring o
allowing for expansion and contraction and the like. The globe 7 is then replaced.
In the modification shown in Fig. 6, the mechanism chamber e is shown as
formed in one with the frame disc and the bottom of the chamber is removable.
The yoke rods are screwed to a flange on the casing e. By this construction the
mechanism can be got at without interfering with the connections.
In the modification shown in Figs. 7 and S the balls are replaced by curved
wedge shaped contact pieces v.
Having now particularly described and 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. The construction and arrangement of the frame of the enclosed are lamp
consisting of the central frame tube, the frame dise with mechanism. chamber
scoured thereto, and the lower yoke secured by yoke rods to the chamber and the
glass bell, the whole forming a perfectly closed chamber to which the regulating
power is admitted through a small sliding joint, substantially as described.
2. The construction and arrangement of the frame and supporting parts of the
lamp substantially as described with reference to the drawings so as to form a
small perfectly closed chamber to which the regulating power is admitted through
a small sliding joint.
3. The means for connecting the regulating mechanism to the core of the
solenoid.
4. The means for securing the enclosing casing for the regulating mechanism
in position, substantially as described.
5. The improved electric are lamp, substantially as described with reference to
the drawings.
Dated this 25th day of Arienst 180e
WHEATLEY & MACKENZIE,
40, Chancery Lane, London, W.C.,
Agents.