IMPROVE- MENTS IN ELECTRIC ARC LAMPS
Year: 1884

page_text: We FREDERICK THORNTON of 228 Burdett Road Telegraph Engineer and OTTO
ROMANZE of 6 Florence Terrace Millwall Telegraph Instrument Maker both in the
County of Middlesex, do hereby declare the nature of our invention for "IMPROVE-
MENTS IN ELECTRIC ARC LAMPS" to be as follows:-
ذر
This invention has for its object improvements in electric arc lamps.
For controlling the descent of the upper carbon holder we employ a quick
threaded screw the rotation of which is controlled by an escape wheel fast upon it,
the teeth of which engage with pallets on a vibrating pallet lever. The carbon
holder descends by its own weight whenever the screw is allowed to turn and the
screw cannot turn without vibrating the pallet lever.
When the upper carbon requires to be lowered the pallet lever is allowed to
vibrate and when it has been lowered to the extent required the pallet lever is
stopped from vibrating and the descent of the upper carbon is thereby arrested.
To arrest the vibration of the pallet lever whenever necessary we employ a
solenoid coil (through which the electric current is passed) to act upon a soft iron
core to which the stem of the quick threaded screw is coupled so that when the
carbons are brought together and the current passes freely the soft iron core is
drawn upwards and so lifts the screw and with it the upper carbon holder and
separates the carbons.
A serrated plate is by the same movement brought against a point carried by the
vibrating pallet lever and the vibrating movement of the pallet lever is thereby
arrested-When the amount of current which is passing through the solenoid coil
is insufficient to hold up the iron core the core descends so again allowing the
pallet lever to vibrate and the screw to turn so that the carbon holder again
descends.
The stem of the carbon holder is tubular and can slide endwise in an outer
tubular casing this casing can also slide a short distance upwards or downwards
but cannot turn.
The quick threaded screw passes downwards through the tubular stem of the
carbon holder and screws into a nut within it-The upper end of the stem of
the screw can turn but cannot move end wise in a bearing formed at the top of the
outer tubular casing. Above this bearing the stem of the screw carries the
escapement wheel.
The outer tubular casing has secured around it an iron tube which forms the
iron core of the solenoid,

page_text: The outer casing has also a flange projecting from it-it rests on a coiled spring
by which the greater part of the weight of the carbon holder and iron solenoid
core can be sustained. By varying the strength of this Spring the lamp can be
adjusted to work with varying strengths of electric current."
A high resistance solenoid coil in shunt circuit is also made to surround the
outer tubular casing of the carbon holder-it acts upon the lower end of the iron
core in opposition to the main solenoid coil and controls the action of the main coil
upon the core: By raising or lowering this shunt coil and so varying its position
with reference to the soft iron core the length of the arc may be regulated or the
lamp can be adjusted to work with any strength of electric current.
When a fresh carbon is to be inserted into the upper carbon holder the upper
holder can be pressed upwards by hand and as it cannot turn it turns the quick
threaded screw.
The escapement wheel is not fast on the stem of the screw but
carries a spring pawl which engages with the teeth of a ratchet wheel that is fast
on the stem of the screw so that the screw can turn freely in the reverse direction
to that in which it is turned when the carbon is to be lowered without turning the
escapement wheel.
+
Just before the upper carbon holder has descended to its lowest point a
projection from it may be made to come against the tail end of a contact lever and
by giving a slight movement to this lever break the circuit and cut off the current
from the lamp.
AM
By a further descent of the carbon holder the lever will be turned still further
until a wedge piece which is pressed by a spring towards V teeth on, the lever is
lifted by the action of one of the teeth pressing against it and so soon as the point
of the tooth passes the point of the wedge the wedge will spring inwards and turn
the switch arm quickly into position to complete the circuit of another lamp and
so bring that lamp into action in place of the one from which the current had been
cut,off.
EU
In place of the solenoid coils being one below the other, the two wires may both
be wound on to one bobbin.
4
The two carbons might also be arranged to feed towards one another so that the
focus of the lamp may remain in the same place.
Y

page_text: We, FREDERICK THORNTON of 228 Burdett Road Telegraph Engineer and OTTO
ROMANZE of 6 Florence Terrace Millwall Telegraph Instrument Maker both in the
County of Middlesex do hereby declare the nature of our invention for "IMPROVE-
MENTS IN ELECTRIC ARC LAMPS" and in what manner the same is to be performed
to be particularly described and ascertained in and by the following statement:-
This Invention has for its object improvements in electric arc lamps.
For controlling the descent of the upper carbon holder we employ a quick
threaded screw the rotation of which is controlled by an escape wheel fast upon it,
the teeth of which engage with pallets on a vibrating pallot lever. The carbon
holder descends by its own weight whenever the screw is allowed to turn and the
screw cannot turn without vibrating the pallet lever.
When the upper carbon requires to be lowered the pallet lever is allowed to
vibrate and when it has been lowered to the extent required the pallet lever is
stopped from vibrating and the descent of the upper carbon is thereby arrested.
To arrest the vibration of the pallet lever whenever necessary we employ a
solenoid coil (through which the electric current is passed) to act upon a soft iron
core to which the stem of the quick threaded screw is coupled so that when the
carbons are brought together and the current passes freely the soft iron coré is
drawn upwards and so lifts the screw and with it the upper carbon holder and
separates the carbons. A serrated plate is by the same movement brought against
a point carried by the vibrating pallet lever and the vibrating movement of the
pallet lever is thereby arrested. When the amount of current which is passing
through the solenoid coil is insufficient to hold up the iron core the core descends
so again allowing the pallet lever to vibrate and the screw to turn so that the
carbon holder again descends.
The screw screws into a nut which is fast upon the stem of the carbon holder
and the stem of the carbon holder is free to slide end wise along a bar or tube which
can also slide a short distance upwards or downwards but cannot turn.
The quick threaded screw lies lengthwise along this bar and the upper end of its
stem can turn but cannot move endwise in a bearing formed at the top of the bar..
Above this bearing the stem of the screw carries the escapement wheel.
The bar also passes through and is secured to an iron tube which forms the iron
core of the solenoid.
A portion of the weight of the iron core and of the carbon holder can be upheld:
by a spring or springs, the strength of which can be adjusted and the lamp be
thereby adapted to work with any strength of electric current.
A high resistance solenoid coil in shunt circuit is also made to surround the
outer tubular casing of the carbon holder-it acts upon the lower end of the iron
core in opposition to the main solenoid coil and controls the action of the main
coil upon the core.
By raising or lowering this shunt coil and so varying its position with reference
to the soft iron core the length of the arc may be regulated or the lamp can be
adjusted to work with any strength of electric current.
When a fresh carbon is to be inserted into the upper carbon holder the upper.
holder can be pressed upwards by hand and as it cannot turn it turns the quick:
threaded screw. The escapement wheel is not, fast on the stem of the screw but
carries a spring pawl which engages with the teeth of a ratchet wheel that is fast
on the stem of the screw so that the screw can turn freely in the reverse direction

page_text: escapement wheel.
In place of the solenoid coils being one below the other the two wires may both
be wound on to one bobbin.
The two carbons may if desired be arranged to feed towards one another so that
the focus of the lamp may remain in the same place.
The drawings hereunto annexed shew various views of an electric arc lamp
constructed as above described.
Figure 1 is a front elevation of the lamp showing the connections complete,
Figure 2. is a sectional elevation, Figure 3 à cross section taken just below the
solenoid coils, and Figure 4 is a plan of the top of the lamp-A is a solenoid coil of
thick wire through which the main current flows, B is another solenoid coil of fine
wire forming a shunt to the main circuit, C is a hollow cylindrical core attached to
the bar D. E is an arm projecting from the upper end of the bar D it forms a
bearing for the upper end of the quick threaded screw F. G is a nut that works
on the screw, the nut is fixed to a bar H which can slide up and down in dovetail
guides formed along the bar D and which at its lowest extremity carries the top
carbon holder J, so that the weight of the top carbon holder with its attachment H
tends to revolve the quick threaded screw F and to allow the top carbon holder to
descend, K is an escape wheel mounted upon the upper end of the screw F and
L is a vibrating escapement lever the vibration of which can (when the core is
drawn upwards) be arrested by a plate E¹ carried at the end of the arm E being
brought against the point of a screw L¹ carried by the escapement lever. The
support for the bottom end of the screw F is carried by a crosshead M fixed across
the lower end of the bar D-this crosshead is suspended by springs N N¹, which
allow of fine adjustment of the amount of weight which has to be raised by the
action of the solenoid coil.
The escape wheel K carries a pawl which engages with the teeth of a ratchet
wheel that is fast on the stem of the screw, this allows the top carbon holder to be
pushed up quickly without moving the escape wheel K whenever a new carbon is
to be inserted. P is a cut out and QR are resistance coils arranged to act
automatically when the carbons are used up or when from any other cause the
lamp fails to work; thus introducing into the main circuit a resistance equal to
that of the lamp so as not to interfere with the working of other lamps in the
same circuit. The cut out P is a solenoid, whose core is pressed upwards by means
of a spring and makes contact between two metallic strips S, S¹, see figures 1
this completes the circuit through the resistance coils QR.
and 3;
The screw X on top of lamp, and the projection Y of the arm E form stops
limiting the distance of travel of the bar D.
To start the lamp the top carbon is allowed to descend till it touches the bottom
carbon, the resistance through the carbons is then less than through the resistance
coils Q and R and the current will pass through the carbons the circuit being as
follows; from the first terminal T to U and bottom carbon, thence through the
top carbon to the flexible connector W to the top electro magnet coil A through
small electro-magnet coil of cut out P and thence to the second terminal V of the
lamp, or vice versa; the current flowing in the coil of the cut out P.draws the
core of this cut out downwards against the action of the spring and breaks
the connection between S and S¹, thus leaving the circuit through the carbons the
only one by which the current can pass; the current at the same time passing
through wire coil A attracts the core C upwards and separates the top and bottom
carbons and establishes the arc, the length of the arc will then be regulated by the
position of the core in the solenoids A and B, as the current falls or lowers. The
solenoid core drops and allows the escapement lever to vibrate and the screw to
revolve, the wheel K will so be allowed to turn one or two teeth and the carbons
will be brought closer together, the current will immediately increase and the core
will again be drawn upwards and the movement of the vibrating escapement lever
be arrested.

page_text: When the carbons are used up or when from any other cause the lamp fails to
work the core of the cut out P being no longer drawn downwards by the passage
of the current is pressed upwards by its spring and makes contact between the
two metallic strips S, S¹, the current then passes from the terminal T down the
pillar U up the pillar U through the resistance coil Q and the resistance coil R
and from the lower end of this coil to the second terminal V through the
strips S, S¹
Figures 5 and 6 are front and side elevations of the lower part of the lamp
moditied in such manner as to allow the focus of the arc to always remain. in the
same position relatively to the lamp. To do this the top carbon holder has a cord
or chain connected to it which is passed over a pulley A. thence round a pulley B,
fixed to a sliding bar C which carries the bottom carbon holder and to fixed arm D,
the position of this arm can be adjusted to suit length of the cord or chain. As
the top carbon descends the bottom one is drawn up half the distance, this being
practically the ratio of consumption of the carbons.
Instead of using two separate solenoid coils the same result can be attained by
winding the fine wire coil over the exterior of the thick wire coil and by so
connecting the ends of the wire coils that they act differentially; one drawing the
core upwards, while the other is tending to pull it downwards.
We have shewn in the drawings the lamp with a cut out and resistance coils
applied to it to introduce into the circuit a resistance equal to that of the lamp
whenever the lamp from any cause fails to work but we make no claim to the
construction of this cut out.
Having now particularly described and ascertained the nature of our said
Invention and in what manner the same is to be performed we declare that what
we claim is:—
First. The construction of electric are lamps either with or without automatic
cut out mechanism substantially as herein before described and illustrated in the
drawings.
Second. The combination in an electric arc lamp of a bar capable of slight
endway up and down movement and having secured to it a core or mass of iron
acted upon in opposite directions by the electric current passing through two
insulated wire coils-one a coil of thick wire through which the main current
passes to lift the bar the other of thin wire through which a shunt current passes-
also of a screw mounted lengthwise of the bar, also of a stem carrying the upper
carbon holder and capable of sliding up and down in guides carried by the bar
and having secured to it a nut through which the screw works so that the weight
of the stem and the carbon holder tends to turn the screw, also of an escapement
wheel on the axis of the screw and a vibrating escapement lever engaging there-
with which lever has to vibrate whenever the screw is turned and also of a stop
carried by the bar to arrest the vibration of lever whenever the bar is raised
substantially as described.