Year: 1898

page_text: I, ARTHUR MARSHALL ARTER, of Linden House, Upper Mall, Hammersmith, in
the County of Middlesex, Engineer, do hereby declare the nature of this invention
to be as follows:-
This invention relates to the carbon-adjusting apparatus of electric-arc lamps
which are adapted to work with either continuous or alternating currents and in
which the holder of the upper carbon is made heavier than that of the lower
carbon and both are connected to opposite sides of the periphery of a wheel that
18 suitably supported by means of a spring or an equivalent and is provided with
a part of smaller diameter to the periphery of which is connected the core of a
solenoid, the arrangement being such that if no curient be passing through the
lamp the weighted top carbon will normally touch the bottom carbon so that upon
the completion of the lamp-cucuit an electic current will pass through the
carbons and the solenoid and will actuate the core of the latter so as to pull the
axle of the wheel down against the action of the spring and also to rotate the
wheel partially, and thereby to move the carbons a suitable distance apart to
strike the arc, after which the carbons will be similarly kept sufficiently apart
against the action of the weighted top carbon-holder, which will gradually feed
then forward
In one construction of focussing lamp according to this invention, the positive
and negative carbon holders are canned by suitably guided rods having cords,
chains, or the like (hereinafter called cords) connected thereto, the cord from the
top carbon-holder passing to a groove m the periphery of the portion of larger
diameter of a differential pulley to which it is secured, whilst the cord from the
bottom carbon-holder passes to another groove on the said portion of the differen-
tial pulley and is also secured thereto, the cords depending from opposite sides of
the pulley A portion of smaller diameter of the differential pulley has secured
to it a cord which depends from the same side as the cord of the bottom carbon-
holder and is attached at its lower end to a lever connected at its free end to the
core of a series solenoid and mounted at its other end on a spindle, which passes
through a slot or hole in the differential pulley and is carried by a fixed support
and on which is also mounted the boss of a forked arm whose free end carries
the differential pulley on a spindle The arrangement may be such that when
the pulley is drawn down by the solenoid in the adjusting operation, it will not
he rotated relatively to the forked arm but will simply revolve therewith about
the pivot of the latter, this arrangement will allow of a weaker sping and a
weaker solenoid than would otherwise be necessary To an extension of the forked
aim there is secured a spring which is attached to the fixed framework of the lamp
and supports the differential pulley In the case of an alternating-current lamp
the core may be composed of discs of 11on arranged at 1ight angles to the axis of
the solenoid The pulley may be so weighted or its centre of gravity may be
so arranged that it will compensate for the gradual decrease in the tendency of the

page_text: carbon-holders to approach each other due to the consumption of the carbons;
the diameter of the portion of the pulley on which the cords rest may be such
that the pulley will make about half a revolution during the consumption of a
pair of carbons and that the weight of the pulley will act in opposition to the weight
of the top carbon-holder during the first half of the travel and as an assistance
thereto during the second half. The spring may be arranged in a somewhat
inclined position so as to give a nearly uniform turning moment in order that
equal variations in current may cause the solenoid to produce practically equal
movements of the axle of the differential pulley. Instead of the spring there
may be used a weight secured, for example, to an extension of the forked arm
The cord that passes round the boss of the differential pulley may be connected
directly to the solenoid core instead of indirectly, and in that case the centre-line
of the core may advantageously be tangential to the periphery of the boss of the
pulley Again, in addition to the series solenoid, a shunt solenoid may be pro-
vided to act in opposition to the series solenoid
Instead of connecting the carbon-holders with the wheel controlled by the
solenoid, by flexible means such as cords the holders may be positively connected
to the wheel by means of toothed tacks engaging with teeth formed on the
wheel In this case the apparatus might with suitable modifications be inverted
e. the wheel and its solenoid might be placed below the carbons
In heu of leading the cord to the top carbon-holder duectly thereto from the
pulley, it may be passed over a guide-pulley, which may be arranged alightly
below the starting position of the highest point of the pulley In this case, the
arm carrving the differential pulley may be pivoted so as to tuin about an axis
outside the pulley
I, ARTHUR MARSHALL ARTER, of Landen House, Upper Mall, Hammersmith, in
the County of Middlesex, Engineer, do hereby declare the nature of this invention
and in what manner the same is to be performed to be particularly described and
ascertained in and by the following statement,―
This invention relates to the carbon-adjusting apparatus of electric-arc lamps
which are adapted to work with either continuous or alternating curients and in
which the holder of the upper carbon is made heavier than that of the lower
carbon and both are connected to opposite sides of the periphery of a wheel that
18 suitably supported by means of a spring or an equivalent and is provided with
a part of smaller diameter to the periphery of which is connected the core of a
solenoid, the arrangement being such that if no curent be passing through the
lamp the weighted top carbon will normally touch the bottom carbon so that upon
the completion of the lamp-circuit an electric current will pass through the
carbons and the solenoid and will actuate the core of the latter so as to pull the
axle of the wheel down against the action of the spring and also to rotate the
wheel partially, and thereby to move the carbons a suitable distance apart to
strike the arc, after which the carbons will be similarly kept sufficiently apart
against the action of the weighted top carbon-holder, which will gradually feed
them forward An arc-lamp of the kind referred to is described in the Specifi-
cation of Letters Patent previously granted to me and numbered 13304 of 1898,

page_text: Figs. 1 and 2 of the accompanying drawings represent, by way of example
and respectively in sectional elevation and in sectional plan (drawn to different
scales), a focussing lamp according to this invention In such a lamp the positive
and negative carbon-holders 1 and 2 are respectively carried by rods 3 and 4
guided suitably, as by and in tubes 3" and 4*, and having cords 5 and 6, chaine,
or the like (hereinafter called cords) connected thereto. The cord 5 from the
top carbon-holder does not pass over any guide-pulley, like the cord 5 of the lamp
shown in Figs 1 and 2 of the aforesaid specification, but passes directly to a
groove 7 in the periphery of the portion 8 of larger diameter of a differential
pullev P to which it is secured, whilst the cord 6 from the bottom carbon-holder
passes to another groove 9 on the portion 8 of the pulley P and is also secured
thereto, the two coids 5 and 6 depending from opposite sides of the pulley A
boss or portion of smaller diameter 10 of the pulley P has secured to it a cord 11
which depends from the same side as the cord 6 of the bottom carbon-holder and
is attached at its lower end to a lever 12 connected at its free end to the core 13
of a series solenoid 14 and mounted at its other end on a spindle 15
The axis
of oscillation of the lever 12 does not lie wholly outside the pulley P, as does the
axis of the corresponding lever 16 in the lamp shown in Figs 1 and 2 of the
aforesaid specification, but the spindle 15 passes through a slot or hole 16 in the
differential pulley P The spindle 15 is carried by a fixed support 17, on which
18 also mounted the boss of a forked aim 18 whose free end carries the differential
pulley P on a spindle 19 To an extension 20 of the forked aim 18 there is
secured a spring 21 which is attached at 21* to the frame of the lamp, this
spring 21 elastically supports the differential pulley P
When the electric current is switched on with the carbons in contact, it
energizes the solenoid 14, which, by means of its core 13. the lever 12 and the
coid 11, revolves the differential pulley P about the spindle 15 against the action
of the spring 21, whilst the weight of the top carbon-holder rotates the pulley
slightly in the direction indicated by the arrow of Fig 1 so that the carbons both
descend together for a short distance in contact with each other, and, as the
tension of the spring and consequently the resistance to the loweung of the axis
of the pulley increases, the solenoid stops the rotation of the pulley about its own
axis in the said direction and stukes the arc by continuing to revolve the dif-
ferential pulley P, together with the forked arm 18, about the spindle 15-the
arrangement is preferably such that during this continued drawing down of the
puller P by the solenoid, the pulley is not thereby rotated relatively to the forked
arm 18 in the direction opposite to that indicated by the arrow, such arrangement
allowing of a weaker sping 21 and a weaker solenoid 14 than would otherwise be
necessary As the resistance of the arc increases through the burning away of
the carbons, a correspondingly decreased current passes through the solenoid, so
that the pull of the core plus the weight of the bottom carbon-holder no longer
counter balances the pull of the weighted top carbon-holder, which then partly
rotates the pulley in the direction indicated by the arrow, lowering the top carbon
and raising the bottom one until the increased current passing through the sole-
noid stops further rotation of the pulley and thus regulates the length of the are
between the carbons As the carbons burn away, the weight supported by the
spring 21 18, of course, reduced, and the spring slightly raises the forked arm 18
and with it the differential pulley P, so rendering the position of the arc slightly
higher than it would otherwise be The strength of the spring 21 18 such that,
whilst it supports the pulley and the parts carried thereby at a suitable height
when no cuiient is passing through the lamp at expands to such an extent, when
the arc is being struck, that the resistance of the ate is consistent with the pas-
sag of normal curent through the solenoid
When the lamp is intended to be worked by continuous current, the differential
pulley P is preferably so weighted--by means, it may be, of a weight 22-01 its
centre of gravity may be so arranged that it will approximately compensate før

page_text: the gradual decrease in the tendency of the carbon-holders to approach each other
due to the unequal consumption of the two carbons; the diameter of the portion
of the pulley on which the cords 5 and 6 rest may then be such that the pulley
will make about half a revolution during the consumption of a pair of carbons and
that the weight of the pulley will act in gradually decreasing opposition to the
weight of the top carbon-holder during the first half of the travel and as a
gradually increasing assistance thereto during the second half. When the lamp
is to be used with alternating ourrent, such a compensating arrangement of the
centre of gravity of the pulley is unnecessary and undesirable, but in that case
the core 13 of the solenoid is preferably composed of discs of iron arranged at
right angles to the axis of the solenoid. The lengths of the solenoid and its core
must, of course, always be such as to allow of their properly regulating the
length of the arc notwithstanding the fact that the core will be gradually moved
outwards during the winding up, by the differential pulley P, of the cord 11,
attached to the core.
The spring 21 may, as shown, be arranged in a somewhat inclined position,
instead of vertically as in the lamp shown in Figs 1 and 2 of the aforesaid speci-
fication, so as to give a more uniform turning-moment in relation to the spindle 15
for equal angular movements of the lever 12 than would be the case with a ver-
tical spring, in order that equal variations in curient may cause the solenoid to
produce more nearly equal movements of the axle of the differential pulley; it
will be evident that with this inclined arrangement of the spring a force less
than would be requned if the spring were vertical will be sufficient, after the
expansion of the sping due to the weight of the parts supported by it, to produce
the requisite lowering of the pulley in striking the aic and that a more convenient
equivalent of a longer vertical spring is thereby obtained
The cold that passes 1ound the boss of the differential pulley may be con-
nected directly to the solenoid core 13, instead of indirectly, and in that case the
centre-line of the core may advantageously be tangential to the periphery of the
boss of the pulley.
Instead of a simple series solenoid, it is found better to employ a differentially
wound solenoid in which the strength of the series winding is greater than that
of the shunt winding--preferably being about four times the strength of the
latter, when the lamp is intended to be worked in series with others, such a
differentially wound solenoid (or its equivalent, as a selles solenoid having a
separate shunt coil to act in opposition to its series coil) is necessary.
Instead of a sping, it is obvious that there might be employed a weight
attached to one end of a cord whose other end would be passed around and con-
nected to a suitable eccentrically mounted pulley so that the force in opposition
to the action of the solenoid would incieuse and decrease substantially like that
of the spring on the oscillation of the lever 12
Instead of connecting the carbon-holders with the wheel controlled by the
solenoid, by flexible means such as cords, the holders may be positively connected
to the wheel by means of toothed racks engaging with teeth formed on the
wheel In this case the apparatus might with suitable modifications be inverted
In an
e., the wheel and its solenoid might be placed below the carbons.
inverted apparatus the cords 5 and 6 might still be used if attached to upwardly
extending rods cariying the carbou-holders 1 and 2 respectively
An equivalent of the difference in weight of the carbon-holders may be arrived
at by arranging for the carbons to be fed at different rates, as by providing the
pulley P with portions of different diameters for the cords 5 and 6 and passing
the latter around the said portions and securing them thereto
Having now particularly described and ascertained the nature of the Baid
invention and in what manner the same is to be performed I declare that what
1 claim 18
-
1. In an electric-aic lamp the combination of a heavier top carbon-holder and

page_text: a lighter bottom carbon-holder both connected, without the intervention of any
guide pulleys, to opposite sides of the periphery of a wheel which is supported
by a spring (or its equivalent) attached to an arm whose axis of oscillation is not
wholly outside of the wheel, and a solenoid whose core 18 connected to the peri-
phery of a portion of smaller diameter of the wheel and which is adapted to
counterbalance normally the excess of weight of the top carbon-holder and to
strike and regulate the length of the arc without the assistance of any mechanical
escapement substantially as set forth
2 An electric-arc lamp of the kind herein before referred to, in which the
spring supporting the wheel is arranged in a somewhat inclined position, sub-
stantially as set forth.
3 My improved electric-arc lamp constructed as hereinbefore described with
reference to and shown in the accompanying drawings
For the Applicant,
W. LLOYD WISE,
46, Lincoln's Inn Fields, London, WC., Chartered Patent Agent.