IMPROVEMENTS IN ELECTRIC ARC LAMPS
Year: 1883

page_text: PROVISIONAL SPECIFICATION left by the said Francis Murray Newton at
the. Office of the Commissioners of Patents on the 9th July 1883.
FRANCIS MURRAY NEWTON of Belfast in the County of Antrim Ireland
"IMPROVEMENTS IN ELECTRIC ARC LAMPS
13
I
1 In an electric arc lamp according to my invention the carbon or electrode or its
holder is held in position by a bush or cylinder (which may be split and adjusted
to various diameters by means of a set screw) lined with a number of Elastic or
spring arms, fingers or feelers axially inclined. to the carbon in the direction in
which motion is to be produced This bush I usually make in one piece and rock
it so that one side is rising or advancing while the other is falling or receding but
sometimes it may be convenient to make it in two parts divided parallel to the
axis of the carbon. The feed is produced by the reciprocating motion of the lining
on opposite sides of the carbon one portion rising or advancing while the other falls
or recedes.
The elastic character and axial inclination of the lining enables each opposing
side of the bush, while giving frictional support to the carbon or electrode or its
holder, alternately to slip along it in the one direction and to bring the carbon
Electrode or holder forwards or downwards in its return the bearing and inclination
of the lining only permitting the slip to take place in one direction.
This forward motion of the carbon or Electrode or its holder may be effected by
a circuit of high resistance acting as a shunt to the arc in the case of lamps
intended to burn in series, and in the case of lamps arranged in parallel arc by a
shunt circuit preferably of high resistance which is brought into action by a
diminution of the current in a portion of the main circuit circulating round a
Price fd1

page_text: magnet or solenoid or two magnets or solenoids with their like poles opposite each
other and acting therefore by repulsion which allows the completion of the shunt
circuit by a spring which brings in a contact when the main current falls below a
given limit which can be varied by regulating the tension of the spring.
In either case the necessary reciprocating motion may be produced by an auto-
matic make and break in the actuating shunt circuit or by short circuiting or
reversing the direction of the whole or a portion of it automatically by any well
known means the said shunt current being made to circulate around an electro
magnet or solenoid or any combination of magnets and solenoids that may be
found convenient

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Francis Murray Newton in the Patent Office on the 9th January
1884.
FRANCIS MURRAY NEWTON of Belfast in the County of Antrim Ireland
IMPROVEMENTS IN ELECTRIC ARC LAMPS
:
In an electric are lamp according to my invention the carbon or electrode or
its holder is held in position by a bush or cylinder (which may be split and
adjusted to various diameters. by means of a set screw) lined with a number of
elastic or spring arms, fingers or feelers axially inclined to the carbon in the
direction in which motion is to be produced. This bush I usually make in one
piece and rock it so that one side is rising or advancing while the other is falling
or receding, but sometimes it may be convenient to make it in two parts divided
parallel to the axis of the carbon. The feed is produced by the reciprocating
motion of the lining on opposite sides of the carbon one portion rising or advancing
while the other falls or recedes.
'
The elastic character and axial inclination of the lining enables each opposing
side of the bush, while giving frictional support to the carbon or electrode or its
holder, alternately to slip along it in the one direction and to bring the carbon or
electrode or holder forwards or downwards in its return the bearing and inclination
of the lining only permitting the slip to take place in one direction.
This forward motion of the carbon or electrode or its holder may be effected by
a circuit of high resistance acting as a shunt to the arc in the case of lamps
intended to burn in series, and in the case of lamps arranged in parallel arc by a
shunt circuit preferably of high resistance which is brought into action by a
diminution of the current in a portion of the main circuit circulating round
a magnet or solenoid, or two magnets or solenoids with their like poles opposite
each other and acting therefore by repulsion which allows of the completion of the
shunt circuit by a spring which brings in a contact when the main current falls
below a given limit which can be varied by regulating the tension of the spring.
In either case the necessary reciprocating motion may be produced by an'
automatic make and break in the actuating shunt circuit or by short circuiting
or reversing the direction of the whole or a portion of it automatically by any
well known means the said shunt current being made to circulate around an electro
magnet or solenoid or any combination of magnets and solenoids that may be
found convenient.
Referring to the accompanying two sheets of drawings.
:
Fig 1 is a plan of an arc lamp embodying my invention, the cover being supposed
to be removed.
Fig 2 is an elevation partly in section
Fig 3 is an elevation at right angles to Fig 2.
:
: *
A is a vibrating device connected to the arm B which is pivotted at the point C,
about which it can freely rock. The interior of the device A which surrounds the
carbon or electrode is provided with fingers or feelers (arranged radially round the
carbon or its holder, but having a slight permanent set or deflection in the direction
of the arc) here shewn as elastic wires fixed in a foundation of metal, leather, or
india-rubber after the manner of wire card filletting. The points of these wires
-normally enclose a cylindrical space rather less in diameter than the carbon D (or
holder) they are intended to grasp and hence when the carbon D (or holder) is
passed through them from above they are deflected and thus form a series of toggle
like arms which oppose but a very slight resistance to the motion of the device A

page_text: '
(relatively to the carbon or holder) in one direction, but take a firm grip on the
carbon or holder when moved forward in a direction approximately parallel to the
axis of the carbon or holder. A¹ is a spring catch or clasp similar to a book clasp
When A' is
by means of which the spring clip device A is opened or closed.
pressed outwards the pin A2 which catches in a hole in A' is released and the clip
flies open sufficiently to allow the carbon holder when necessary to be slid upwards.
The clasp may be provided with à set screw to enable the pressure of A' on the
carbon or holder to be adjusted.' è è is.a carbon holder which may be a solid rod
or tube ending with a clamp to grasp the carbon, or may be a thin tube of the
same diameter, as the lower part of the carbon externally, but having the lower
end 'coned internally for a short distance to fit a 'corresponding cone on the end of
the carbon (see Fig 4) This form of holder is used where it is important to have as
short a lamp as possible for being the same diameter as the carbon it may be made
to follow it down through the device A and guide at N, thus enabling a longer piece
of carbon to be burned than, would be possible in a lamp having a bolder which
could not be pushed up above. N. The vibration or rocking of the device A is
effected by the electro magnet E, which is situated in a shunt circuit around the
arc in a manner which is well understood. This magnet attracts an armature Ex
connected to the vibrating device A, but so long as the arc does not exceed its
normal length the attraction, is not sufficient to overcome the power of the spring F.
When, however, the length of the arc increases beyond the determined amount the
attraction of the magnet overcomes the spring and the armature is drawn down,
rocking the device A on its centre or pivot. The wires on one side of it advance
towards the arc in a direction approximately parallel to the carbon, carrying the
carbon or its holder with them, while those on the other side retreat from the arc
sliding over the carbon or its holder., Those wires which from their situation near
the pivots neither approach towards, nor recede from the are during the rocking
motion do-not of course aid, in effecting the feed. After a very slight motion the
shunt circuit is broken, where it crosses the contact points at I. The magnet loses
its power and the armature rises rocking the device in. the opposite direction,
whereupon the wires which in the previous motion slid over. the carbon or its
holder take a frictional hold of it feeding it forward, while those which gripped it
.slide over it ready for their next stroke. In a short time the contact is again made
and, if the arc is not already reduced to its normal length the rocking action is
¡continued until it is.
His a small contact spring making contact with a platinum point in the screw I
supported by the arm and column J. This spring serves to vary the length of the
stroke of the rocking arm B, for by raising or depressing the screw I the distance
through which B must travel before the spring H is carried out of contact with I
may be diminished or increased.
KK are contact springs attached to the socket L which also carries the tube M
and shield N the lower end of the tube M being reduced in diameter and serving
as a guide for the carbon or holder. O is a ring which allows adjustment of the
pressure of springs K-K to be made by sliding O up or down, and securing it by
set screw
The course of the current through the lamp is as follows: it enters at the
terminal P, passes by a wire to the socket L, thence through the contact springs K K
to the upper carbon across the arc to the negative carbon and from its holder to
the core T of the electro magnet. One end of the coil surrounding T is connected
to the core, and hence it receives the current which is conveyed from the other end
of the core by a wire to the rod.R.and thence by a second wire to the other
terminal Q. The shunt circuit passes up, through the positive carbon from the
contact springs K K to the device A thence to the pivotted arm B and through the
contact pieces at I to the column J, and through the electro magnet E to the
terminal Q
The arc striking electro magnet. consists of a central iron core T forming one
pole and a cylindrical sheath of iron U connected at the lower end to T whose

page_text: upper end forms the other pole of the magnet. The wire V is wound as shewn
between T and U one end of the coil being connected to T, and the other passing
through a slot in U to R. W is an iron keeper of circular form whose upper end
is coned to receive the split ball X, and screwed externally to fit the conical
socket Y by screwing down which the carbon is clamped in any desired position.
Z is a small conical piece inserted below the ball-X to prevent its getting far out of
position when the carbon is changed or removed. The armature W is secured to
the non-magnetic screw a which is pressed up against the attractive force of the
magnet by the spring b whose tension can be adjusted by the screwed plug c. The
core T is extended to d, and serves to support the glass globe if required by means
of any suitable device attached thereto.
The object of N is to shield the lamp from the rising gases.
Figs 5 and 6 shew a slightly modified arrangement of lamp according to my
invention. In them the carbon holder is shewn solid, but it may also be made
hollow to lighten it, and terminating in a clamp. The contact springs K and
shield N are omitted and the holder is guided by the bush L and receives the
current through the split wire brush K¹ which is, in connection by a strip of copper
with the positive terminal.
Figs 7 and 8 shew a modified form of lower carbon holder-which can be used
with either form of lamp, in place of the one previously described, when the lamp
is intended to burn in parallel arc with others.
a a is a spool of brass or other non magnetic metal with a screwed part b by
which it can be attached to the cross-bar of the lamp. This spool is wound with
coils of insulated wire d one end of which is connected to the spool, and the other
to the rod W which is in connection with the negative terminal of the lamp, but is
insulated from the cross bar V carrying the spool a. cc is an iron core having a
cylindrical sheath of the same material firmly attached to it and enveloping the
upper portion of the spool a, which it fits accurately. The whole forms a dashpot
which controls the motion of the core c, a cushion of air being enclosed in the
annular space e e, and also beneath the core at f, where a spiral spring is placed
which retains c in the position shewn, when the lamp is not in action.
Attached to c is shewn the split ball and socket carbon holder previously
described the lower portion of which may conveniently be made in one piece
with c.
The action of the device is as follows:-The coils of wire around a form
a solenoid or sucking magnet. When the current passes through them c is drawn
in compressing the spring at f. Suddenness of motion is prevented by the air
cushion at ee which gradually escapes by leakage between the periphery of a and
the interior of the cylindrical part of c. The carbons are thus separated slowly
and gradually instead of with a sudden jerk as with the magnet Z. When the
lamps are required to burn in parallel I sometimes place a small electro magnet in
the main circuit acting upon the bar B (Fig 5) in the opposite direction to the
magnet E E. Or E E may be wound with two circuits in opposite directions, one
consisting of very few turns of thick wire in the main circuit, and the second of a
large number of turns of very fine wire forming a shunt to the arc. In either case
the force tending to set the bar B in vibration will be proportional to the difference
between the magnetic pull due to the coils in the shunt and main circuit and
therefore where the lamps have to work in parallel arc, or singly with a battery of
constant electromotive force since the pull due to the shunt coils will be constant,
the starting of the vibration of the bar B and therefore the feed of the carbons will
depend on the variations in the strength of the main current.
Having thus described the nature of the said invention and the manner in
which it is to be performed I would have it understood that what I consider to be
novel and original and therefore claim in an arc lamp as the invention secured to
me by the Letters Patent berein before in part recited is :-
1. The use for feeding the carbon of an oscillating or rocking device lined
with elastic or spring arms, fingers or feelers, so arranged that while part are

page_text: advancing carrying the carbon towards the arc, part are receding into position for
the next forward or acting stroke, substantially as described.
2. The combination with a feeding device, such as referred to in the preceding
claim of a solenoid or electro magnet whereby the said device is made to oscillate
or rock substantially as described.
3 The combination with a feeding device, such as referred to in the first claim
of an electromagnet or solenoid and a make-and-brake, apparatus substantially as
described
4 The improved lamp as described and illustrated in Figs 1 to IV inclusive also
the modification thereof illustrated in Figs 5 to 8.
In witness whereof I the said Francis Murray Newton have hereunto set my
hand and seal this third day of January in the year of Our Lord one thousand
eight hundred and eighty four.
T
תומINm
F. M. NEWTON
(L.S.)