IMPROVEMENTS IN AND APPLICABLE TO ELECTRIC ARC LAMPS
Year: 1883

page_text: LETTERS PATENT to John Thomson King of Liverpool in the County of´
Lancaster Patent Agent for an Invention of IMPROVEMENTS IN AND
APPLICABLE TO ELECTRIC ARC LAMPS communicated to him from abroad by
Joseph R Finney of Pittsburgh Pennsylvania in the United States of
America
PROVISIONAL SPECIFICATION left by the said John Thomson King at the
Office of the Commissioners of Patents on the 7th April 1883.
JOHN THOMSON KING of Liverpool in the County of Lancaster Patent Agent
"IMPROVEMENTS IN AND APPLICABLE TO ELECTRIC ARC LAMPS." [communicated
to him from abroad by Joseph R. Finney of Pittsburgh Pennsylvania in the United
States of America]
The main objects are to simplify the construction; to render the action more even
and regular to effectually control the length of the arc and to prevent accidents
to any lamp of a series from acting detrimentally on the rest.
The invention consists First. In constructing electric arc lamps with a hollow
core electro magnet through which the feed rod of the top carbon or electrode
passes in combination with a gripper or grippers disposed so as to act on the said
feed rod and to be actuated radially by the varying magnetism in the said hollow
core electro magnet. The electric current to operate the lamp passes from the main
or line wire through the coil of the hollow core electro magnet, thence through the
feed rod, upper carbon, lower carbon and thence to the main or line wire. The
frame binding screws and other parts of the lamp such as for raising the top carbon
are constructed in any usual or suitable manner.
Second. The gripper or grippers above mentioned are so arranged that the
varying action of electric currents on the hollow core electro magnet shall impart
to the said gripper or grippers both a radial motion and a vertical motion in the
direction of the longitudinal axis of the top carbon feed rod. In this case the
gripper or grippers serve to retain the top carbon in position and to raise it out of
contact with the lower carbon.
Third. In combination with the gripper or grippers under the above second part

page_text: a spring or springs is or are employed to regulate the vertical or axial motion of
the said gripper or grippers.
to be
Fourth. In combining with electro magnets used in operating the carbon feeding
devices of electric arc lamps, a spring controlled armature connected to the top carbon
feed rod and a contact maker connected to the line wire and pivotted so
free to vibrate or to be tipped from side to side. The action of the apparatus is
as follows. when the carbons of the lamp become too far separated owing to
combustion the reduction in the current passing through the electro magnet allows
the armature to be moved by its controlling spring so as to strike the vibrating or
tipping contact maker and short circuit the lamp for a moment through the top
carbon feed rod and cause the carbon to fall sufficiently to reduce the arc to its
normal length.
Fifth. In combining with the vibrating or tipping contact maker above
mentioned an additional contact maker connected to the main or line wire so that
should the lamp become damaged and the passage of the current through it
prevented the spring controlled armature would rise and strike against the addi-
tional contact maker and the current would pass direct from the main or line wire
through the said additional contact maker thence through the armature and again
to the main or line wire. Suitable resistance coils or their equivalents are placed
in the connections between the main or line wire and the additional contact inaker
and armature to prevent the current passing therethrough except when the lamp is
not in working order.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said John Thomson King in the Great Seal Patent Office on the
6th October 1883.
"
JOHN THOMSON KING of Liverpool in the county of Lancaster, Patent Agent.
"IMPROVEMENTS IN AND APPLICABLE TO ELECTRIC ARC LAMPS communicated to
me from abroad by Joseph. R. Finney of Pittsburgh Pennsylvania, one of the
United States of America.
The main objects are; to simplify the construction: to render the action more
even and regular, to effectually control the length of the arc and to prevent accidents
to any lamp of a series from acting detrimentally on the rest.
The invention consists. First. In constructing electric arc lamps with an annular
or hollow core electro magnet through which the feed rod of the top carbon or
electrode passes, in combination with a gripper or grippers disposed so as to act on
the said feed rod and to be actuated radially by the varying magnetism in the said
hollow core electro magnet. The electric current to operate the lamp passes from
the main or line wire through the coil of the hollow core electro magnet, thence
through the feed rod, upper carbon, lower carbon and thence to the main or line
wire. The frame, binding screws and other parts of the lamp such as for raising
the top carbon are constructed in any usual or suitable manner.
Second. The gripper or grippers above mentioned are so arranged that the
varying action of electric currents on the hollow core electro magnet shall impart
to the said gripper or grippers both a radial motion and a vertical motion in the
direction of the longitudinal axis of the top carbon feed rod. In this case the
gripper or grippers serve to retain the top carbon in position and to raise it out of
contact with the lower carbon.
Third. In combination with the gripper or grippers under the above second part
a spring or springs is or are employed to regulate the vertical or axial motion of
the said gripper or grippers.
Fig 1 is an elevation partly in section and figs 2 to 7 detail views of the improved
lamp under the above first and third parts.
In all the views like letters denote the same parts.
The lamp has a frame composed of two arms a a connected at the top and
bottom by cross-pieces a' a³ preferably of disc form The upper disc a¹ is insulated
from the arms a by collars a³ of insulating material, and is provided with binding
posts at a³ for the attachment of the conducting wires n and On the upper sido
of the disc a' is an annular or hollow core electro magnet 6 the bore of which is
lined with tubes b' of diamagnetic material, of sufficient diameter to permit
the easy passage of the feed rod d of the movable electrode of the lamp.
The core 6 of the magnet extends through the disc a¹. Fastened to the
under side of the latter is a flat strap or support e the end of which
is bent at a right angle and is perforated for the passage of the feed
rod d. Resting on the support e is a pair of grippers, the jaws c of which
are pivotted together by means of side plates c and pins or pivots c².
jaw has an arm to which is fastened an armature ct. The meeting
edges of the jaws are slightly bevelled at one side of the pivots as shown
at c, to permit them to have a slight radial movement. This is illustrated in
figures 3 and 4, figure 3 showing the jaws open and figure 4 closed, as when
gripping the feed rod. The electro magnet b is provided with a cap or cover f
which has a tubular extension ƒ¹ to cover the feed rod d and of sufficient length
to permit its vertical movement. One end of the coil of the magnet terminates
Each

page_text: The
at the core, and the other in the binding post a³, which is insulated from the frame.
The lower disc a³ is perforated for the passage of the lower carbon or electrode,
which is secured therein by means of a set screw a³. The lower disc a¹ is provided
with a shade holder a and the upper disc with a retaining flange a.
carbons or electrodes are shown at g g¹, the upper one being secured to the rod d
by means of socket and set screw d¹. A chimney shaped shade is used which
is put in place by removing the lower carbon and then passing the shade up
around the upper carbon and into the retaining flange a' until it will slip over
the edge of the shade holder a into place. Then the lower carbon is replaced from
below. The circuit wires n and p are connected with the corresponding poles of
a dynamo-electric machine or other source of electricity. The circuit is by the
wire p, electro magnet b, rod d, electrodes g g', frame a, and wire n back to the
generator. When the core 6 of the magnet becomes magnetized by the passage of
the current through its coils, the armatures are drawn inwards radially until
the jaws c grip the rod d, and then they are drawn or attracted upwards carrying
with them the rod, whereby an axial movement is given to the rod, and the points
of the carbons are separated sufficiently to form the arc. When the core becomes
partially demagnetized by the burning off of the electrodes, the grippers gradually
descend and sink outwards radially until the rod slips downwards between them
and fully re-establishes the circuit. The core becoming then fully magnetized
again attracts the armatures, thereby causing the grippers to sieze and raise the
rod. The feeding device just described is very sensitive and causes the lamp to
burn with great smoothness and freedom from violent pulsations. The radial
movements of the jaws being just sufficient to grip and release the rod, are very
slight, the slight bevels co being amply sufficient to permit such movement. The
extent of the axial movement depends on the size of the arc desired, and may be
limited by the distance left between the upper ends of the armatures and the lower
end of the core of the magnet.
The power of the attraction of the magnet increases as the armatures are raised.
In order to equalize this and prevent the formation of too great an arc, which
would produce a voilent pulsation of the light, at the instant the feed occurred.
A spring e¹ is provided under the third part of the proper tension to overcome or
equalize the force of the attraction of the magnet at any given point, and thereby
regulate the length of the arc. I do not limit myself to the use of my lamp
provided with such a spring, but claim it either with or without the spring.
Figures 8 to 11 show a modification of lamp under the first and third parts.
This lamp is a bracket lamp, having a frame h on the upper end of which is
sustained an electro-magnet h¹ similar to the magnet b. The lower carbon is
insulated from the frame h by a 'tube h³ of insulating material the set screw h³
being also insulated by an insulating collar h*. The wires and p pass up and
down through the tubular frame ; one <P> being coiled to form the coils of the
n
electro-magnet ², its end terminating in contact with the core; the other
passing down into contact with the inner tube h³ of the lower carbon holder. The
wire n is properly insulated, by suitable insulating covering from the frame. The
grippers are placed on top of the electro-magnet. In this case the arms i', to
which the armatures i are attached, are formed of a spring metal such as hardened
brass, so as to be capable of being drawn inwards slightly, after the grippers bite
on the feed rod d, for the purpose of causing them to raise the rod sufficiently to
separate the points of the carbons and thus form the arc. In figure 8 the upper
disc he of the electro-magnet h¹ is formed with inclines, which, when the armatures
are drawn inwards aid in raising the feed rod d. The amount of spring necessary
in the arms ¹ and in the jaws of the gripper is but slight, as it is not desirable to
form a long arc.
Figure 12 shows the upper disc of the electro-magnet h¹ made with a plain face.
The inward movement of the arms of the grippers causes the rod d to be raised
but not to such an extent as is the case with figure 8. The operation of this form

page_text: of a lamp is substantially the same as that before described. When the circuit is
closed the electro magnet attracts the armatures, causing the grippers to grasp the
rod and raise and sustain it until by the burning off of the points of the carbons
the current is weakened and the core of the magnet partially demagnetized, when
the weight of the rod and the upper carbon will cause the grippers to separate and
permit the rod to slip downwards. When the points of the carbons come together
and the circuit is fully re-established, the armatures will again be attracted and will
bite upon and raise the rod as described. The jaws of the grippers may be pivotted
together as shown, or may interlock without being provided with pivots, each jaw
encircling the rod and biting on the side opposite to its armature.
The forms of grippers shown may be varied as long as they operate by radial
movement caused by armatures attached to their ends vibrating in a vertical plane
when the effect of the attraction of the electro magnet is to cause the said grippers
to bite on the rod and sustain it, and the weakening of the attraction permits the
armatures to recede and release the rod.
In figure 13. I show a lamp under the second and third parts. Here the radial
movement of an armature is used to operate a clamping plate or ring. This lamp
is substantially like the other forms described, with the exception of the feeding
devices. Extending from the lower end of the plate k to which the armature k' is
attached, is a ring or clamping plate having a recessed or slotted point which
rests against and pivots on the pin secured on the lower end of a support or
stirrup. The armature is prevented from falling away by means of a slotted
plate or ring at its upper end. The rod d is passed up through the ring land
slotted plate k² and when the circuit is opened hangs in the position shown in
figure 14, but when the circuit is closed the armature k¹ is drawn radially inwards
pivotting on the point until the two opposite sides of the ring 7 bite upon the
rod d. Then its radial movement being checked the armature is drawn towards
or axially of the rod and separates the points of the carbons, establishing the arc.
In this lamp the circuit wire p is insulated from the frame and is connected to
the coils of the electro-magnet m. The wire n is connected to the frame, and the
crosshead m' of the frame is insulated from the arms m³ by insulating collars m³.
The circuit is through the electro magnet, rod d, carbons, frame, and wire n.
When the current becomes weakened by the burning off of the points, the
armature ² falls backwards and releases the rod, thereby permitting it to slido
until the points of the carbons come together and re-establish the circuit.
connection with this part of my invention, the essential features of the third part
of the invention are the radially moving electro-magnet as a means for operating
the clamping ring biting on the opposite sides of the feed rod. Where other
provision is made for separating the carbon points and establishing the arc, it is
only necessary to give a radial movement to the armature, as its only function then
is to clamp and hold the rod.
In
The
The fourth part consists in combining with electro magnets used in operating
the carbon feeding devices of electro arc lamps, a spring controlled armature
connected to the top carbon feed rod and a contact maker connected to the line
wire and pivotted so as to be free to vibrate or to be tipped from side to side.
action of the apparatus is as follows; when the carbons of the lamp become too
far separated owing to combustion the reduction in the current passing through
the electro magnet allows the armature to be moved by its controlling spring so as
to strike the vibrating or tipping contact maker and short circuit the lamp for a
moment through the top carbon feed rod and cause the carbon to fall sufficiently
to reduce the are to its normal length.
The Fifth part consists in combining with the vibrating or tipping contact
maker above mentioned an additional contact maker connected to the main or line
wire so that should the lamp become damaged and the passage of the current
through it prevented the spring controlled armature would rise and strike against
the additional contact maker and the current would pass direct from the main or
line wire through the said additional contact maker thence through the armature

page_text: and again to the main or line wire Suitable resistance coils or their equivalents
are placed in the connections between the main or line wire and the additional
contact maker and armature to prevent the current passing therethrough except
when the lamp is not in working order.
Figures 17 to 22 illustrate the above fourth and fifth parts for preventing one of
the lamps from "robbing" the other lamps of the circuit and also means of short
circuiting a lamp, in case of any stoppage in the feeding of the same. It happens
sometimes that the grippers fail to let go of the rod d soon enough, or that the
magnetism of the core remains so great, while the current continues to pass through
the coils of the magnet b even when the resistance of the arc has increased
considerably that the armatures are still sufficiently attracted to prevent the
grippers from releasing the feed-rod, causing an abnormal increase of the arc
producing a flaming of the same, with a decrease of current through the other
lamps. This is what is referred to by the use of the term "robbing." To prevent
this means of short circuiting the coils of the electro-magnet b has been devised
after the arc of the lamp has reached a determined size. Hinged upon the top
flange 6 of the magnet b at one side of the rod d, is a plate q¹ carrying an
armature q both armature and plate being provided with a hole for the passage of
the carbon rod d of sufficient size to permit the movement of the armature without
interfering with the operation of the rod. Back of the hinge is a spring q² which
effects the retraction of the armature. The outer end of the plate q¹ is faced on its
lower side with an insulating plate q³ which extends laterally slightly beyond one
side. Secured to the top of the inagnet on that side is a bracket 1, which is
insulated, by an insulating layer, from the magnet frame. Pivotted to the
bracket r is a vertical plates having a lower arm 8¹ projecting under the end of
the plate q¹ and a short projection or spur 8 projecting slightly over the edge of
the plate. The plate & is provided with a weight 83 mounted on an arm directly
over the centre of gravity, so that if the plate is tipped in either direction the
weight will hold it there. The insulator ¹ extends below the lower edge of the
plate 8, so as to prevent the latter from ever coming in contact with the magnet
frame. A conductor p extends from the wire p to the bracket r and is thereby
in electrical connection with the plate 8. When the plate s coines in contact with
the plate by means of the latter striking the spur the current passes from the
conductor p by means of the wire p¹ and plate s to the plate q' and from the latter
to the top plate of the magnet frame, and thence by the core and conducting
springt to the electrodes. The spring t which presses lightly against the feed rod,
is provided with a collar t¹ which rests loosely on the lower brass sleeve of the
magnet core to sustain the spring in position.
The devices just described operate in the following manner. The pressure of the
retracting spring q* is regulated by means of a screw q. The power of magnetism
necessary to attract the armature is slightly in excess, more or less as experience
will demonstrate to be necessary, of that which effects the operation of the grippers,
so that the armature q will be retracted before the armatures of the grippers are
released. As the are grows longer the power of the magnet decreases. In time this
will permit the retraction of the armature q. The plato q' rising strikes the point
or spur which as stated is electrically connected to the conductor p by the wire pl
and bracket r. The current will then pass thereby directly to the core b² and rod d,
short circuiting the magnet coils, there being greater resistance in the latter. The
weight of being thrown past the centre of gravity will hold the plate s in a tipped
position until by the descent of the plate q¹ it is restored to its normal position.
The current continues to pass through the plate q' during the time it is rubbing
past the point 8². When the plate q has passed the point &², the projecting edge
of the insulating layer 2³ strikes the point 83 and throws the pivotted plate & far
enough over to permit the plate q¹ to return without striking the point. The
instant the coils are short circuited, as described, the core becomes demagnetized
and permits the armatures ct of the grippers c to fall and release the rod d. As
soon as the plate q¹ passes the point s², the current again passes through the magnet

page_text: coils, magnetizing the core and attracting the armatures q and c'. As the plate q
descends it encounters the lower arm of the pivotted plates and restores the
latter to its normal position. These movements are so rapid that the plate q¹ does
not have time to rise into contact with the upper arm s of the plate 8, the functions
of which will be described.
The above described mechanism prevents the establishment of too great an arc
and the robbing of the lamps before mentioned. It acts upon the principle of short
circuiting the magnet when an arc of a determined resistance has been formed. If
the circuit through the lamp is interrupted from any cause, the lamp will be cut
out of circuit by the following means. The upper arm 8 of the plate s is insulated
from the plate by an insulator 85 A wire 2ª extends from the wire p² to the
arm and a wire 23 extends from the magnet frame out to the wire n, said wire p³
having a resistance or resistance device of any suitable character, greater than the
resistance of the lamp. So long as the lamp is operating the current passes
through it, but if the circuit through the lamp is broken, the armature plate q',
being released, will spring up until it comes in contact with the arm &* and the
current will pass through the wire p², arm 8ª, plate q¹, flange b³. and wire p³ to
line. Thus an accident to or destruction of a lamp will not be fatal to the
circuit.
Having now described and illustrated the nature of the said invention in such
manner that others will be enabled to carry my improvements into effect I
claim :-
Under the first second and third parts. 1. In an electric-arc lamp an electro-
magnet perforated longitudinally for the passage of the feed rod of the movable
electrode, in combination with a pair of gripping jaws provided with armatures
capable of a radial movement in a vertical plane; substantially as, and for the
purposes described.
2. In an electric-arc lamp, an electro-magnet, and a pair of gripping jaws
provided with armatures and capable of a radial movement in a vertical plane; in
combination with a feed rod passing between and operated upon by said grippers,
substantially as described.
3. In an electric arc lamp, an electro magnet, and a pair of gripping jaws
provided with armatures and capable of an axial and a radial movement in a
vertical plane, in combination with a feed rod passing between the said jaws so as
to be gripped and raised theroby, substantially as and for the purposes described.
4. In an electric arc lamp, an electro-magnet perforated for the passage of the
feed rod of the movable electrode; in combination with a pair of gripping jaws
provided with armatures placed above the electro-magnet and encircling the feed
rod, and capable of an axial movement in a vertical plane substantially as and for
the purposes described.
5. In an electric arc lamp an electro magnet and a pair of gripping jaws
provided with armatures capable of a radial movement in a vertical plane; in com-
bination with a feed rod passing between and operated upon by said grippers, and
a spring interposed between the grippers and the electro magnet substantially as
and for the purposes described.
"
6. In an electric arc lamp an electro magnet perforated for the passage of the
feed rod of the movable electrode, in combination with an armature provided with
a clamping plate encircling the feed rod and having a radial movement in a vertical
plane, substantially as and for the purposes described.
Under the fourth part. In an electric arc lamp, an armature operated by the
magnet which operates the feeding devices, in combination with a tipping contact
device electrically connected with the circuit wire, whereby when the armature is
retracted it will close circuit with said contact device and short circuit the magnet
coils, substantially as and for the purposes described.
Under the fifth part. In an electric arc lamp, an armature, operated by the
magnet which operates the feeding devices electrically connected with one of the
circuit wires; in combination with a contact device electrically connected with

page_text: the other circuit wire: so that when the circuit is broken through the lamp the
armature shall be retracted and strike said contact device, and thereby cut the
lamp out of circuit, substantially as and for the purposes described.
In Witness Whereof I the said John Thomson King have hereunto set my hand
and seal this fifth day of October in the year of Our Lord, one thousand eight
hundred and eighty three.