Improvements in Are Lamps.
Year: 1899

page_text: Improvements in Are Lamps.
JOSEPH DEVONPORT FINNY ANDREWS, 45, Fulham Park Gardens, London, S.W.,
Electrical Engineer, do hereby declare the nature of this invention to be as
follows:-
My present invention relates to the construction of arc lamps in which a sole-
noid is used to control the arc & a dashpot to overcome the inertia of the moving
parts of the lamp.
In one form of my invention I attach one of the carbons preferably the lower
one to the frame of the lamp & I attach the other direct to a core of a solenoid.
I arrange the core to slide in a tube which acts as a guide or bearing.
The tube would preferably be constructed of non-magnetic metal, such as brass
or it may be of an insulating material. The guide tube would be placed in a hole
somewhat larger than itself, forming the centre of a solenoid. I fix the guide
tube to one end of the solenoid in such a manner that its other end is moveable.
The method I prefer is a ball or half ball joint made suitable to convey the
current to the tube. The core in the tube would be provided with a contact
brush, consisting of a piece of thin sheet metal fixed by its centre into a slot in
the end of the core, thus forming two arms or wings which I would lap round
the core, in which position they would form springs & rub against the inner side
of the tube. If the guide tube be of insulating material I may arrange contact
strips down its interior to convey the current.
When I use metal guide tubes in the case of alternating currents I split it
down one side & slip a second split tube over it with insulating material between.
The splits would be arranged on opposite sides. I would construct the solenoid
preferably without a bobbin & form the ends of it with internal cones. I would
provide a tube outside of the solenoid, of metal or insulating material, with cones
resting or fixed within each end of it, suitable projections being arranged in
one end of the tube to support one of the cones & provision being arranged at the
other for a cap to be screwed on, after the solenoid & second cone have been placed
in, & bind the solenoid between the two cones. The cap would be provided with
an insulator & a central spring contact to connect with the guide tube. The
solenoid would be connected by one end to the ball connector of the tube & by
the other end to an insulated contact in connection with the spring contact in the
cap. The solenoid in its case & with its cone would be placed within a tube
which I would make longer than the case of the solenoid & arrange the portion
of it not occupied by the solenoid to be the cylinder of a dashpot, the piston of
which I would provide on the end of the core.
I prefer to construct my pistons of incombustible material such as steatite or
asbestos. I would employ the asbestos in the form of paper or cloth & form it
in the shape usual with leather pistons in hydraulic pumps.
When I wish to arrange my lamps to have the arc in a fixed position I would

page_text: arrange the lower carbon to move towards the upper carbon in bearings & I would
effect the movement by the weight of the core to which I would attach a cord
band or chain passing over pulleys in any suitable way & connected by its other
end to the lower carbon.
I may connect the core of my solenoid to a brake band on the pulley, or if
there is more than one pulley on one of them, instead of direct to one of the
carbons I would provide the brake band with an adjusting spring at the other
end of it. I would preferably make my brake band of velvet & I may provide
velvet on the periphery of the wheel so as to increase the grip.
In cases where a velvet material might be found a disadvantage I may connect
the brake band to the fulcrum of a lever, one end of which would rest on the
periphery of the wheel & the other end would be attached to the core of a solenoid
or a magnet armature.
may arrange an adjustable stop under the end' of the lever near the brake
band to relieve the weight of it off the wheel at the moment of feeding.
On a pulley attached to the brake wheel I would provide a band or chain, with
one end attached to each carbon holder or with one end attached to one carbon
holder & the other to the pulley itself, or to a weight, or left free suitably guided.
In the event of attaching one end of the chain to the pulley I would make pro-
vision for turning the pulley when new carbons are to be inserted such as a
spring which would be wound up by the weight of the carbon & holder & which
would uncoil & wind the chain on the wheel when the weight of the carbon holder
is relieved by lifting.
Improvements in Arc Lamps.
JOSEPH DEVONPORT FINNY ANDREWS, 45, Fulham Park Gardens, Fulham, S.W.,
Electrical Engineer, do hereby declare the nature of this invention and in what
manner the same is to be performed, to be particularly described and ascertained
in and by the following statement:―
My present invention relates to the construction of arc lamps in which a
solenoid is used to control the arc and a dashpot to overcome the inertia of the
moving parts of the lamp. It has hitherto been considered necessary in lamps
employing a core to move over a long range in a solenoid to vary the diameters
of the core or of the solenoid or both of them in different parts of their length
in order to obtain an even pull throughout the distance of movement.
In my
lamp however I have so proportioned the solenoid in relation to the core that
I am able to construct them both parallel throughout their lengths.
In one form of my invention I attach one of the carbons preferably the lower
one, to the frame of the lamp and I attach the other direct to a core of a solenoid.
I arrange the core to slide in a tube which acts as a guide or bearing.
The tube would preferably be constructed of non-magnetic metal, such as brass
or it may be of an insulating material. The guide tube would be placed in a hole
somewhat larger than itself, forming the centre of a solenoid. I fix the guide 4
tube to one end of the solenoid in such a manner that its other end is moveable.
The method I prefer is a ball or half ball joint made suitable to convey the
current to the tube. The core in the tube would be provided with a contact
brush, consisting of a piece of thin sheet metal fixed by its centre into a slot in
The end of the core, thus forming two arms or wings which I would lap round 6
the core, in which position they would form springs and rub against the inner side

page_text: of the tube. If the guide tube be of insulating material I may arrange contact
strips down its interior to convey the current.
When I use metal guide tubes in the case of alternating currents I split it
down one side and slip a second split tube over it with insulating material between
The splits would be arranged on opposite sides. I would construct the solenoid
preferably without a bobbin and form the ends of it with internal cones. I
would provide a tube outside of the solenoid, of metal or insulating material,
with cones resting or fixed within each end of it, suitable projections being ar-
ranged in one end of the tube to support one of the cones and provision being
arranged at the other for a cap to be screwed on after the solenoid and second
core have been placed in, and bind the solenoid between the two cones. The
cap would be provided with an insulator and a central spring contact to connect
with the guide tube. The solenoid would be connected by one end to the ball
connector of the tube and by the other end to an insulated contact in connection
with the spring contact in the cap. The solenoid in its case and with its core
would be placed within a tube which I would make longer than the case of the
solenoid and arrange the portion of it not occupied by the solenoid to be the
cylinder of a dashpot, the piston of which I would provide on the end of the core.
I prefer to construct my pistons of incombustible material such as steatite
or asbestos. I would employ the asbestos in the form of paper or cloth and form
it in the shape usual with leather pistons in hydraulic pumps..
When I wish to arrange my lamps to have the arc in a fixed position I would
arrange the lower carbon to move towards the upper carbon in bearings and I
would effect the movement by the weight of the core to which I would attach a cord
band or chain passing over pulleys in any suitable way and connected by its
other end to the lower carbon.
I may connect the core of my solenoid to a brake band on the pulley, or if there
is more than one pulley on one of them, instead of direct to one of the carbons
I would provide the brake band with an adjusting spring at the other end of it.
I would preferably make my brake band of velvet and I may provide velvet on
the periphery of the wheel so as to increase the grip.
In cases where a velvet material might be found a disadvantage I may connect
the brake band to the fulcrum of a lever, one end of which would rest on the
periphery of the wheel and the other end would be attached to the core of a
solenoid or a magnet armature.
I may arrange an adjustible stop under the end of the lever near the brake
band to relieve the weight of it off the wheel at the moment of feeding.
On a pulley attached to the brake wheel I would provide a band or chain, with
one end attached to each carbon holder or with one end attached to one carbon
holder and the other to the pulley itself, or to a weight, or left free suitably
guided. In the event of attaching one end of the chain to the pulley I would
make a provision for turning the pulley when new carbons are to be inserted
such as a spring or weight which would be wound up by the weight of the carbon
and holder and which would uncoil and wind the chain on the wheel when the
weight of the carbon holder is relieved by lifting.
Fig. 1. represents a section of one form of my lamp in which A is a carbon
ixed to the frame of the lamp B. C'is a moving carbon fixed by the holder D. to
a core E of a solenoid F. The core E is arranged to slide in a tube G which acts
as a bearing to it and also as a means of conveying the current. The tube G is
uspended within the centre hole of the solenoid F, the hole being somewhat larger
than it, to allow of freedom of movement in the case of any irregularities. This
guide tube terminates at its upper end in a ball joint. the ball or half ball H
being fixed to the tube and resting in the socket I, which is fixed to the solenoid.
T is a plate of insulating material upon which is mounted a brass contact plate K.
A spring L, connected to one of the terminals of the lamp M presses on the contact
olate K. and as a consequence the ball H is pressed into its socket I. One end
of the solenoid is connected to K and the other to I. A. brass plate N is provided

page_text: on the underside of the plate J as being more suitable to press direct onto the
ball H. The connection between the core E and the tube G is effected by a
spring O Figs. 1, 2, & 3 preferably of hard drawn copper_arranged in the shape
of an S and fixed to the core E at its centre P. When I make the tubes G of
insulating material I provide a lining of metal Fig. 4, in which G is the tube
and Qis the lining which I may divide longitudinally by one or more slits R,
in which I may insert insulating material in the case of alternating currents.
Fig. 5 illustrates another modification of this part of my invention for use
especially with alternating or intermittant currents. I construct a tube or two
tubes S&T drawn one over the other and preferably insulated from one another
I split each tube at U & V the splits being preferably arranged diametrically
opposite to each other. I prefer to construct the solenoid F in this form of my
lamp without a bobbin and in order to hold it in position I build each of the ends
with a conical recess, and I would provide a cheek preferably of insulating material
or of metal with a suitable insulation upon it, one for each end. These cheeks
would be provided with conical projections W, W, Fig. 1, to fit into the internal
cones of the solenoid. The flanges of these cheeks would be arranged to fit
within a tube X. This tube would be provided with a bevelled ring Y fixed into
its lower end and the cheek of the solenoid W, would be formed to fit it. At
the upper end of the tube I provide an enlargement or flange Z into which I
screw a ring A2. This ring is bevelled on the under side and into this bevel is
fitted an insulative block 132 which carries the terminals of the lamp. When the
ring A is screwed down its pressure is transmitted to the cheeks with the
cones W, W between which the solenoid is consequently held. I arrange the
tube X to fit within another tube X2 and rest upon its upper end by the flange Z
the tube X being also provided with a flange 72 at this point. The tube X2
is longer than the tube X and the excess length extends below the tube X and
is made use of to constitute a dashpot and also the carrier of the frame B. I
arrange the piston of the dashpot on the end of the core E and I construct it of
a disc of metal E, a cup of asbestos E2, another disc of metal E covered with
asbestos E, the whole being rivetted together at intervals as shown at E5 round
the periphery or held in any other suitable manner and held onto the end of the
core by a nut D³.
In Fig. 6 I illustrate the modification of my lamp in which I employ a break
in addition to the solenoid. As is the lower carbon which may be fixed as shown
or it may be attached to a moveable holder suspended on one end of the chain
or cord B in the known manner. C is the upper carbon held in a moveable
holder suspended on the other end of the chain B. D is a pulley and break wheel
combined, over which the chain or band B plays. E, is the break band attached by
one end to the adjustable spring F and by the other to the fulcrum G of an arm H,
one end of which rests on the break wheel, and the other end is linked to the
end of the core I, which is suspended by its upper end to an adjustible spring J.
K is the solenoid suitably held by arms from the main support, a stop L suitably
supported is provided so as to lift the arm H off the wheel D when the operation
of feeding is to take place. The break E may be of velvet or any other material
and I may dispense with the arm H when the material is of sufficient gripping
power.
Having now particularly described and ascertained the nature of my said in-
vention, and in what manner the same is to be performed, I declare that what I
claim is
1. In an arc lamp, the combination of a solenoid having equal diameters
throughout its length, with an iron core having equal diameters along its length
and having one end connected direct to one end of one of the carbons, and also
having at one end of it a piston working in a dashpot substantially as described
and illustrated.
2. The construction of piston substantially as described and illustrated in
Fig 1

page_text: 3. The construction of a guide tube with spring contact fixed to the core and
with ball and socket adjustment as described and illustrated.
4. The method of supporting a solenoid and connecting same electrically in
an arc lamp, substantially as described and illustrated in Fig. 1.
5. The general construction of an arc lamp substantially as described and
illustrated in Fig. 1.
6. The construction of an arc lamp as described and illustrated in Fig. 6.