IMPROVEMENTS IN ELECTRIC ARC LAMPS
Year: 1882

page_text: LETTERS PATENT to John Lea, of Clarence Gardens Regent's Park, in the
County of Middlesex, Telegraph Engineer for an invention of IMPROVEMENTS
IN ELECTRIC ARC LAMPS
PROVISIONAL SPECIFICATION left by the said John Lea at the Office of
the Commissioners of Patents on the 22nd April 1882.
JOHN LEA, of Clarence Gardens Regent's Park in the County of Middlesex,
Telegraph Engineer, IMPROVEMENTS IN ELECTRIC ARC LAMPS,
My invention has for its object the better regulation of the feed of the carbon,
or carbons, in order to ensure a steady light; and, at the same time to be able to
employ carbons of greater length than heretofore.
According to my Invention the upper carbon is held in position by rollers (by
preference, three) two of which are held in a metal frame for their bearings, while
the third is a riding or "jockey" roller, adjustable to any given pressure by means
of a spring and adjusting screw. These rollers are so constructed as to allow of
different sized carbons being placed between them.
The feeding action for lowering the upper carbon, as consumed, is as follows:
A solenoid, or an electro magnet, is employed and actuates a gripping lever for the
purpose of revolving the rollers and this solenoid, or electro magnet is connected
as a shunt from the main circuit. This shunt circuit is divided to allow of a
variable resistance in order to increase or decrease the motion of the feeding
lever.
.
A second solenoid, or electro magnet, is employed to form the are by separating
the upper and lower carbons.
A projecting arm is placed upon the frame of the jockey roller in such a position
that, should the carbons be apart, the feeding solenoid, or electro magnet ncts upon
and releases the jockey roller, and allows the carbons to come into contact.
A short circuiting arrangement is placed upon the frame of the jockey roller, so
that when the upper carbon is consumed a contact is made and the lamp cut out,
but allowing all the other lamps in the same circuit to continue burning
In another arrangement a solenoid, or an electro magnet is placed upon a frame
in such a position that the gripping levers shall act directly upon the upper carbon
or carbon holder in such a manner as to obtain the same feeding action without
the above mentioned rollers.
The cores of the solenoids or electro magnets may be made of iron, but in some
cases I prefer to make the same of a bundle or iron wires.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said John Lea in the Great Scal Patent Office on the 19th October 1882.
JOHN LEA of Clarence Gardens, Regent's Park in the County of Middlesex,
Telegraph Engineer IMPROVEMENTS IN ELECTRIC ARC LAMPS
My invention has for its object the better regulation of the feed of the carbon,
or carbons, in order to ensure a steady light, and at the same time to employ
carbons of great length, so that what is known as a single lamp (that is, one pair
of carbons acted upon by one set of feeding apparatus) shall burn for a long time
without attention.
I attain these objects by the mechanism illustrated in the accompanying
drawings, in which figure 1 is a front elevation and fig. 2 a side elevation of my
improved electric arc-lamp. Fig. 3 is a diagram showing the direction of the
currents when the lamp is alight.
According to my invention, the upper carbon-is-held-in-position by rollers a, u¹, a²,
(by preference three) two of which a and a¹ are mounted in a metal frame A,
which frame also carries a fraune b, in which is mounted the third roller a². This
third roller is a riding or jockey roller, adjustable to any given pressure, by means
of the spring c, adjusting screw c², and thumb nut c, the spring being attached to
the frame of the jockey_roller at c³. This jockey roller, as shewn in the drawings,
is in the position it would occupy if a carbon of large diameter (as represented by
the dotted lines) say of an inch, be placed in the lamp between the riding or
jockey roller a² on the one side, and the two rollers a. a. on the other side.
Should a carbon of smaller diameter-be placed-in--the-lamp, the jockey_roller would
close upon it by the action of the spring c, and by means of the nut c², sufficient
tension can be put upon it to prevent its weight revolving the three rollers, and
allowing the carbon to fall through by gravitation. The roller a is of larger
diameter than the other two rollers, and all these rollers are grooved, to allow of
different sized carbons being placed between them.
The lower or negative carbon is held in its place by a clamp n (fig. 2) and is
maintained therein by a screw n', so placed that the said screw n¹ will hold any
size carbons in a line with each other.
The feeding action, for lowering the upper carbon, as it is consumed, is as
follows:-
A solenoid M, or an electro magnet, is employed, and actuates a gripping lever d,
for the purpose of revolving the rollers, and this solenoid (or electro-magnet is
connected as a shunt from the main circuit; this shunt circuit is divided to allow
of a variable resistance by being wound differentially, or in two parts. When the
first part of the wire is wound on, a wire m is attached and is brought out of the
coil, and then attached to a metal block e, to which is fastened a spring f, the
second part of tho wire m¹ is then wound on, but in the opposite direction, and its
end brought out, and attached to the metal base plate of the lamp at 2, or this
Eccond wire may be placed in the lamp as a resistance coil and a branch wire from
the connection run up to the spring and attached to it at one end, and the other
end of this resistance coil attached to the base plate.
M' is the core of the feeding solenoid.
The metal block e, to which is fastened the spring f, is placed upon an adjusting
screw g, passing through a block of insulating material h, so that by turning the
screw g the spring can be lowered, as required. Upon the end of this spring, is
a platinum piece j, and another platinum piece jx, on the gripping lever d, to form
contact to cut out the resistance coil or second wire, upon the solenoid, or electro-
magnet.

page_text: The gripping lever d is suspended at its outer extremity by a spiral spring k
and an adjusting screw ', which latter passes through the angle piece B, secured
to the top of the frame A. The other end of this gripping lever is jointed upon
two arms 8. 8¹ which are connected to the frame A, on each side of the roller a, and
fit loosely on bush pieces 8*, let into the frame through which passes the arbor
upon which the roller revolves.
A second solenoid W (or an electro-magnet) is employed to form the arc by
separating the upper and lower carbons. It is shewn arranged in fig. 1 on the
opposite side of the frame A, with its spiral spring w, adjusting screw w², gripping
lever d' and arbor, much the same as on the feeding side.
The core N of this solenoid has a projecting piece n attached to it, and from
this piece a rod o extends downwards until it passes through an arm O. This rod
is thinned down for a short distance to form a spring (or a spring may be inserted
therein, as shewn) when it again takes the same shape as the portion above the
spring, and abuts against a piece R, attached to the frame A. At this point the
rod has a pin or stud r which strikes against and catches a cam Q, when the lamp
is extinguished, and by the spring w pulling up the core N displaces the jockey
roller a³ by the stud r catching the cam and pulling forward the extension piece Z
on the long arm Y, thus allowing the carbons to come together ready for
relighting, and not depending solely on the stud p on the jockey roller frame P.
B is a bent arm carrying set screws t. t'. against which the arms 8. 82. rest
allowing the spiral springs and w. to just pull the gripping levers d. d' off the
periphery of the roller a.
At the bottom of each solenoid is a piece of iron S. S'. held fast therein by being
screwed into the base plate. These pieces S. S¹ serve to draw down the cores M¹
and N of the solenoids M and W attached to the gripping levers d and d¹ and on the
are making side to hold down the core firmly.
On the arc-making side is an arm or lever x, bent into the position shewn in
fig. 2, and fixed to the axis d³ of the gripping lever ', so that when the iron
core N of the solenoid W is drawn into the coil, this arm or lever presses
against the side of the frame A, and by so doing, releases the gripping lever from
the roller a
An upwardly projecting arm P is placed upon the frame of the jockey roller,
and is furnished with a pin or stud p which is so arranged thereon as to be
caught by the feeding lever d, should the carbons be apart, and to act upon and
release the jockey roller, and allow the carbons to come into contact.
A short circuiting arrangement is also placed upon the frame of the jockey
roller, so that when the upper carbon is consumed, or if by accident, the carbon
should break, contact is made at y, upon the insulated stud y', which is in
connection with the negative terminal, and as the positive terminal is in connection
with the frame A, short circuit is made, and the lamp cut out. If the upper
carbon should be consumed, until the top of such carbon descends below the
roller a, then by the pressure caused by the spring c, the upper carbon would be
displaced, the jockey roller would be drawn inwards, and the long arm Y would
come in contact at y. y* is a copper wire making good connection, for short
circuiting. The wire connecting the short circuiting stud y' to the negative
terminal, may be of the same resistance as the arc, if required, so that the
resistance of the line will remain the same, if part of the circuit be turned off.
Of course, it will be understood that electro-magnets will answer the same
purpose as the solenoids, by using armatures or keepers in place of the iron cores.
My improved construction of lamp may be used either with direct currents, or
with alternating currents, if alternating currents bo used. I then prefer to employ
a bundle of iron wires, in place of iron tubes, or solid iron cores.
The action of the lamp is as follows:-
When to be lighted, and should the carbons be apart, the current enters at the
positive terminal and traversing the shunt coil M pulls down the core M' until the
gripping lever & comnes against the stud p, on the arm P, and displacing the jockey

page_text: roller causes the upper carbon to come into contact with the lower carbon. The
current then passing by the thick wire solenoid W, the core of the shunt coil is
drawn back by the spring h, the core N is brought down upon the piece of iron S.
the arm x displaces the gripping lever d, after turning the roller a, in the proper
direction, and the arc is formed.
The core N remains down all the time the lamp is alight. As the are becomes
longer, by the carbons being consumed so more current passes by the shunt
gradually pulling down the core M', until it causes the contact to be broken
between and d, when the greater resistance being thrown in allows the
spiral spring to pull back the gripping lever d ready for the next feed,
and so on.
Having now described my invention and in what manner the same may be
performed, I declare that I claim.
1. The improved Electric arc-lamp constructed and operating substantially as
herein described, and as shewn in the drawings, whereby the feed of the upper
carbon is properly regulated, and a light of great steadiness produced.
2. The special arrangement and combination of grooved rollers, for maintaining
the upper carbon in position, and for feeding the same (as consumed) towards the
lower carbon, substantially as herein described and shewn in the drawings, such
arrangement-and-combination-permitting_carbons of great length and different
sizes to be employed.
3. The employment and arrangement of gripping levers operated by a solenoid,
or electro-magnet, constructed as a shunt of variable resistance, whose second
wire or resistance coil is automatically switched in and out for effecting the
_feed of the upper carbon, substantially as herein described, and shewn in the
drawings.
4. The application and use of a jockey or riding roller substantially as and for
the purposes described, whereby carbons of various sizes can be employed.
5. In combination-with-a-jockey_or_riding roller and its adjustable bearing, a
spring, tension screw and thumb nut, substantially as herein described-and-as-
shown in the drawings, for regulating the pressure of such roller on the upper
carbon.
6. The combination of a roller with gripping levers, stops, arm for releasing the
gripping lever, and solenoid or electro-magnet, all substantially as and for the
purposo herein described, and as shewn in the drawings.
7. The employment of an arm provided with a stop or stud, and so arranged
upon the fraue of the jockey or riding roller, that should the carbons be apart, the
feeding solenoid or electro-magnet acts upon and releases the said roller, substan-
tially as specified and as shewn in the drawings.
8. The arm Y for short circuiting, in combination with the jockey roller frame,
the extension piece Z, with its cam Q, and the rod o with its pin x, all being
actuated by the core of the arc-making solenoid, substantially as herein described,
and as shown in the drawings for the purposes set forth.
In witness whereof I the said John Lea have hereunto set my hand and
seal this Third day of October in the year 1882.