IMPROVEMENTS IN ELECTRIC LAMPS
Year: 1882

page_text: LETTERS PATENT to Edmund Edwards, of 40 Southampton Buildings, Chancery
Lane, London in the County of Middlesex, and Arthur French St. George, of
Redhill in the County of Surrey for an Invention of "IMPROVEMENTS IN
ELECTRIC LAMPS "
PROVISIONAL SPECIFICATION left by the said Edmund Edwards and
Arthur French St. George at the Office of the Commissioners of Patents on
the 3rd October 1882.
2
:
EDMUND EDWARDS, of 40, Southampton Buildings, Chancery Lane, London, in
the County of Middlesex, and ARTHUR FRENCH ST. GEORGE of Redhill in the
County of Surrey "IMPROVEMENTS IN ELECTRIC LAMPS "
"
"
Our invention relates to that form of Electric lamps, or apparatus for producing
light by means of Electricity, which is known as an arc light, in which the
light is produced by the passage of a current of Electricity between the extremities
of carbon rods.
1
In such Electric lamps it is necessary that the extremities of the carbon rods
described should be retained constantly at as nearly as possible the same distance
apart, in order that the light may be steady, uniform, and as free as possible from
flickering and variation, and our present invention has for its object improved
methods of constructing and arranging apparatus by which such distance may be
automatically preserved constant as the length of carbon decreases.
We take two bars or electrodes of carbon, the negative carbon being fixed in a
suitable position in the lamp by screws or other well known means so that one of
the conducting wires is in electrical communication with it. The other or positive
carbon electrode we fit in communication with a conducting wire, in a suitable
guide so that it can be gradually advanced as required toward the fixed carbon,
and its upper end we attach to a screw, or to a support connected to a screw,
which screw works in a corresponding nut so that as the screw is turned in the
latter the carbon is gradually fed forward.
We arrange the nut. so that it can revolve in suitable fixed bearings, in such.

page_text: manner that although it can revolve round or with the screw it cannot move in
the direction of the length of the latter, and formed upon or attached to it we
make a toothed wheel of sufficient diameter into which gears an endless screw or
pinion by which the nut can be made to revolve at any desired speed; and we
cause the nut so to revolve by means of a small engine or device caused to revolve
at a uniform speed by the passage through it of a current of electricity.
Such Engine or device may be made in any of the ordinary well known ways
in which an axle is made to revolve by means of armatures operated upon by one
_ or more magnets or electro magnets through which a current of electricity is made
to pass.
Upon the screw itself, or in connection with it we arrange a second toothed
wheel driven in a similar manner by a second electro magnetic engine or device of
a similar kind, so that if the two Engines are caused to revolve at the same speed,
and in the same direction, the screw and the nut in which it works revolve together
and the carbon and screw remain in the same position relatively to the nut. If,
however, the screw be made to revolve more quickly than the nut, the former will
travel slowly forward through the latter and the carbon will be fed forward,
whilst if the nut be made to revolve more quickly than the screw the latter will
travel slowly backward through the former, and the carbon will be drawn back.
We actúate the two Engines described by separate currents of Electricity, one of
which is diverted from the main conducting wire and passes through the Engine
which drives the screw, whilst the other is the current, or is derived from the
current which passes through the two carbon electrodes and drives, the nut,
suitable adjustable resistance apparatus being inserted where necessary..
If then the carbons become too far separated a proportionately less amount of
Electricity will drive the nut the speed of which will be reduced, and a larger
amount will drive the screw the speed of which will be increased, and the carbon
will be fed forward, until the speed of the two Engines again becomes equal, and
the reverse process will take place if the carbons approach too closely.
If no current pass through the carbons, as when they are first adjusted at too
great a distance, they will be made rapidly to approach, or if they are in contact
they will be made to recede, until in each case the proper distance is automatically
attained.
The nut may be made to revolve by wheelwork, or by a separate current of
electricity, or by other mechanism acting at a uniform adjustable speed, and the
moveable carbon may be made to revolve slowly with the screw, either round its
own axis or round an axis parallel with but slightly removed from its own axis, so
that it is constantly presenting itself to a different point of the fixed or negative
carbon.
!
In a modified form of apparatus we actuate a bar or toothed rack to which the
moveable carbon is attached by means of a pinion or screw upon a light axle
revolving in bearings, and upon this axle at a convenient part of its length we
arrange two bevilled toothed wheels face to face and freely revolving upon the
axis. Upon the axis between these bevilled toothed wheels we fix a transverse
axis upon the ends of which revolve freely two bevilled wheels, preferably of less
diameter, which gear with the two bevilled wheels first described. Attached, or
connected to each of the larger bevilled toothed wheels we arrange a tangent
toothed wheel, each actuated by an endless screw upon an axle revolving in
suitable bearings, the two screws being actuated by electro-magnetic engines or
devices similar to and driven in the same way as those used in the method of
arrangement already described. The two larger bevilled toothed wheels being thus
made to revolve in opposite directions at the desired speed, as long as they travel.
at the same speed their axis remains stationary and the position of the carbons
continues unaltered.. If, however, one travels at a greater speed than the other:
from a variation in the relative quantity of electricity passing through the motors
the axis begins to revolve at a speed proportioned to the difference in their speed
and in a direction varying as one or other of the motors is revolving more quickly

page_text: than the alternate one, and the position of the carbons is accordingly regulated as
required with great exactness.
Electric lamps constructed according to our invention may be fitted into any
suitable ornamental or other frame, and may be arranged vertically or in any other
desired position, and when adjusted they will regulate the position of the carbons
or other electrodes automatically and with perfect accuracy, the slightest differential
variation between the speeds of the two Engines producing an instant corresponding
variation in the position of the carbons.
It will be seen, therefore, that in order to effect the necessary variation in the
position of the carbon or other electrodes in electric lamps, we make use of the
differential action of two actuating devices, each of which is always revolving in
the same direction, and which when running at their proper relative speeds have
no effect upon the longitudinal motion of the electrodes, but when their relativė
speed is altered effect a corresponding variation in the position of the positive
carbon, and we effect such variation in speed by means of the variation of the
quantity of electricity passing from time to time through the electrodes; and we
do not confine ourselves to the precise form of apparatus as described by which the
process is effected, which may be varied to suit varying circumstances.
Apparatus as described may be applied to both electrodes instead of to one only.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Edmund Edwards and Arthur French St. George in the Great
Seal Patent Office on the 3rd April 1883.
EDMUND EDWARDS, of 40 Southampton Buildings, Chancery Lane, London, in
the County of Middlesex and ARTHUR FRENCH ST. GEORGE, of Redhill, in the
County of Surrey "IMPROVEMENTS IN ELECTRIC LAMPS
"
This invention relates to that form of Electric lamp, or apparatus for producing
light by means of Electricity, which is known as an "arc" light, in which the light
is produced by the passage of a current of Electricity between the extremities of
carbon rods or electrodes.
In such electric lamps it is necessary that the extremities of the two carbon rods
.described should be retained constantly at as nearly as possible the same distance
apart, whilst the current remains the same, in order that the light may be steady,
uniform, and as free as possible from flickering and variation, and our present
invention has for its object improved methods of constructing and arranging
- apparatus by which such distance may be automatically preserved constant as the
length of carbon decreases.
We take two bars or electrodes of carbon, the negative carbon being fixed in a
suitable position in the lamp by screws or other well known means so that one of
the conducting wires can be fixed in electrical communication with it. The other
or positive carbon electrode we fit in electrical communication with a conducting
wire, in a suitable guide so that it can be gradually advanced as required toward
the fixed carbon, and its upper end we attach to a screw, or to a support connected
to a screw, which screw works in a corresponding nut so that as the screw is turned
in the latter the carbon is gradually fed forward.
We arrange the nut so that it can revolve in suitable fixed bearings, in such
manner that although it can revolve round or with the screw it cannot move in the
direction of the length of the latter, and. formed upon or attached to it we make
a toothed wheel of sufficient diameter into which gears an endless screw or pinion
by which the nut can be made to revolve at any desired speed; and we cause the
nut so to revolve by means of a small electro-motor engine or device caused to
revolve at a uniform speed by the passage through it of a current of electricity.
Such Engine or device may be made in any of the ordinary well-known ways in
which an axle is made to revolve by means of armatures operated upon by one or
more magnets or électro-magnets through which a current of electricity is made
to pass.
Upon the screw itself, or in connection with it, we arrange a second toothed
wheel driven in a similar manner by a second electro-motor engine or device of a
similar kind, so that if the two Engines are caused to revolve at the same speed
and in the same direction, the screw and the nut in which it works revolve together
and the carbon and screw remain in the same position relatively to the nut. If,
however, the screw be made to revolve more quickly than the nut, the former will
travel slowly forward through the latter and the carbon will be fed forward, whilst
if the nut be made to revolve more quickly than the screw the latter will travel
slowly backward through the former, and the carbon will be drawn back.
We actuate the two Engines described by separate currents of Electricity, one of
which is diverted from the main conducting wire and passes through the Engine
which drives the screw, whilst the other is the current, or is derived from the current
which passes through the two carbon electrodes and drives the nut, suitable
adjustable resistance apparatus being inserted where necessary.

page_text: If then the carbons become too far separated a proportionately less amount of
Electricity will drive the nut the speed of which will be reduced, and a larger
amount will drive the screw the speed of which will be increased, and the carbon
will be fed forward until the speed of the two engines again becomes equal, and
the reverse process will take place if the carbons approach too closely.
If no current pass through the carbons, as when they are first adjusted at too
great a distance, they will be made rapidly to approach, or if they are in
contact they will be made to recede, until in each case the proper distance is
automatically attained.
The moveable carbon may be made to revolve slowly with the screw either round
its own axis or round an axis parallel with but slightly removed from its own
axis, so that it is constantly presenting itself to a different part of the fixed or
negative carbon.
In a modified form of apparatus we actuate a bar or toothed rack to which the
moveable carbon is attached, by means of a pinion or screw upon a light axle
revolving in bearings, and upon this axle at a convenient part of its length we
arrange two bevilled toothed wheels face to face and freely revolving upon the
axis. Upon the axis between these bevilled toothed wheels we fix a transverse
axis upon the ends of which revolve freely two bevilled toothed wheels, preferably
of less diameter, which gear with the two bevilled toothed wheels first described.
Attached or connected to each of the larger bevilled toothed wheels we arrange
a tangent toothed wheel each actuated by an endless screw upon an axle revolving in
suitable bearings, the two screws being actuated by electro-magnetic engines or
devices similar to and driven in the same way as those used in the method of
arrangement already described. The two larger bevilled toothed wheels being thus
made to revolve in opposite directions at the desired speed, as long as they travel:
at the same speed their axis remains stationary and the position of the carbons
continues unaltered.
If however, one travels at a greater speed than the other from a variation in the
relative quantity of electricity passing through the motors, the axis begins to
revolve at a speed proportioned to the difference in their speed and in a direction.
varying as one or other of the motors is revolving more quickly than the alternate
one, and the position of the carbons is accordingly regulated as required with great
exactness.
In the accompanying drawing figure 1 is in illustration of the method of
arrangement just described. It is to be understood however that the relative
positions and proportions of the several parts of the apparatus are neglected in the
drawing, some of the parts being shewn to a larger scale in order that their method
of operation may be more clearly seen. a is one of the carbon electrodes suspended
above the other electrode b by means of a cord or chain c which is connected to a
toothed rack & working freely in guides. e is a pinion gearing with the rack d
and fixed upon the spindle f which revolves in bearings as shewn. Upon the
spindle fis fixed a transverse aring upon the ends of which revolve freely the
bevilled toothed wheels h, h', which gear into corresponding bevilled toothed
wheels i, ¹, which revolve freely upon the axis f. Formed upon or attached to
each of the wheels i, i, is shewn a tangent wheel k, k, actuated by endless
screws 1,, upon the spindles m, m³, which are set in revolution by small electro-
motors of any convenient description as indicated at n, n¹, so that the wheels i, i¹,
revolve at any desired speed in opposite directions.
The electro-motors n, n', are driven by separate currents of electricity, one of
them n, by a current derived from the electricity passing through the main
conducting wire A by means of an adjustable resistance coil or other equivalent
apparatus offering sufficient resistance indicated at 2. The other motor n', is driven
by a part of the current which passes through the electrodes a, b, a sufficient.
quantity of the current being passed through the wires 3, 4, and through the second
adjustable resistance coil or equivalent apparatus indicated at 5.
The apparatus is adjusted so that when the light is burning satisfactorily, the

page_text: points of the electrodes being at the proper distance apart, the quantity of
electricity passing through the motors n, n¹, is such that they revolve at the same
speed, the wheels i, 2, turning in opposite directions but at the same speed, and the
spindle consequently remaining stationary.
When, however, the points of the carbons become too far separate, a larger 5
quantity of electricity will be diverted through the motor n³, the speed of which
will increase, and the spindle f will be turned round sufficiently to bring the carbons
into their normal position again, by the movement of the wheels k, k¹, and cross
bars g caused by the relatively increased speed of the wheel i¹.
If, on the other hand, the carbon a and b, approach too nearly, a greater quantity 1
of electricity passes through them, and the speed of the motor n¹ is relatively
decreased, and the and the spindle is turned in the other direction until the
normal position has been again attained.
Figure 2 is in illustration of the modified method of arrangement first described.
a and b are the electrodes, the upper one a being connected to a screw c which 1
works in a nut d revolving in the fixed bearing e, so that as the nut is turned, the
screw if prevented from revolving, is fed down or up. i is a tangent toothed wheel
fixed or formed upon the nut d and driven by an endless screw / actuated, as in the
arrangement already described, by an electro-motor indicated in dotted lines at n.
A second tangent toothed wheel n¹ is fitted upon the screw c which can pass 2
freely through it endways but is provided with a longitudinal slot or key fitting in
the wheel so that when the wheel n' is turned the screw c is turned with it; and
the second wheel n¹ is driven by the endless screw actuated by a second electro-
motor n. The electro motors n, n', are driven by currents of electricity derived and
applied through adjustable resistance coils or apparatus 2 and 5, in the same way
as in arrangement already described.
Instead the actuating electro-motors being connected directly to the differential
devices described and shewn for regulating the position of the electrodes, additional
toothed wheels and pinions or endless screws may be interposed for the purpose of
reducing or adjusting the speed of movement of the electrode as compared with
that of the electro-motors.
Electric lamps constructed according to our invention may be fitted into any
suitable ornamental or other frame, and may be arranged vertically or in any other
desired position and when adjusted they will regulate the position of the carbons or
other electrodes automatically and with perfect accuracy, the slightest differential
variation between the speeds of the two Engines producing an instant corresponding
variation in the position of the carbons.
It will be seen therefore, that in order to effect the necessary variation in the
positive of the carbon or other Electrodes in electric lamps we make use of the
differential action of two actuating devices each of which is always revolving in
the same direction and which when running at their proper relative speeds have no
effect upon the longitudinal motion of the electrodes, but when their relative speed
is altered effect a corresponding variation in the position of the positive carbon, and
we effect such variation in speed by means of the variation of the quantity of
Electricity passing from time to time through the electrodes; and we do not
confine ourselves to the precise form of apparatus as described by which the process
is effected which may be varied to suit varying circumstances.
For instance one of the motors instead of being driven by a current of electricity
may be driven continuously at a speed as nearly as possible uniform by a separate
current of electricity, or by clockwork or other power giving a constantly available
regular motive force, the regulation of the position of the electrode being effected
by the variations in speed of the other constantly moving electro-motor caused by
the varying quantity of electricity passing through it according to the distance
apart of the electrodes.
Apparatus as described may be applied to both Electrodes instead of one only.
Having now described our invention and the manner in which it is to be
performed, we do not claim generally the use of an electro-motor device for the

page_text: purpose of regulating the position of the electrodes of an electric lamp but we
claim-The combination of two motors each continuously revolving in the same
direction, but their relative speed being varied by the quantity of electricity
actuating one or both of them, such quantity being regulated by the position of the
electrodes themselves, and the differential speed thus obtained being used to
regulate automatically such position of the electrodes, substantially as described
and shewn in the drawing.
In witness whereof, I the said Edmund Edwards, on behalf of myself and
the said Arthur French St: George, have hereunto set my hand and seal
this third day of April in the year of our Lord 1883.
EDMUND EDWARDS. (L.S.)