IMPROVEMENTS IN ELECTRIC LAMPS, PART OF WHICH IMPROVEMENTS ARE APPLICABLE TO OTHER PURPOSES." PROVISIONAL SPECIFICATION
Year: 1881

page_text: LETTERS PATENT to Ernest John Harling, of Guildford Street, Farringdon
Road, and Emil Hartmann, of Compton Street, both in the County of
Middlesex, for an Invention of "IMPROVEMENTS IN ELECTRIC LAMPS, PART
OF WHICH IMPROVEMENTS ARE APPLICABLE TO OTHER PURPOSES."
PROVISIONAL SPECIFICATION left by the said Ernest John Harling and
Emil Hartmann at the Office of the Commissioners of Patents on the
11th August 1881.
ERNEST JOHN HARLING, of Guildford Street, Farringdon Road, and EMIL
HARTMANN, of Compton Street, both in the County of Middlesex. "IMPROVE-
MENTS IN ELECTRIC LAMPS, PART OF WHICH IMPROVEMENTS ARE APPLICABLE TO
OTHER PURPOSES."
This Invention consists in the combination and arrangement of mechanism for
regulating automatically the relative position of the electrodes or points of the
carbons employed in electric lamps, whereby such object is effected in a more
regular and continuous manner than is the case when arrangements of mechanism
as ordinarily constructed are used. That part of the said Invention which relates
to the arrangement of a brake is also applicable to other analogous purposes.
This Invention consists mainly in the employment of a rotating armature of soft
iron (preferably in the form of a disc) which is placed in connection with the
carbon holders for the purpose of actuating the carbons either by means of toothed
wheels and racks attached to the said carbon holders, as is customary in electric
regulator lamps, as will be well understood; or the carbon holders can be suspended
by cords wound off and on drums or fusees, the latter being connected with a train
of wheels.
We will now proceed to describe our Invention when drums or fusees are
employed, as lastly referred to. On the spindle of the rotating armature is a pinion
gearing into a toothed wheel mounted on the spindle of the said fusees; the cord
suspending the positive carbon is wound on the larger fusce in one direction, and

page_text: the cord suspending the negative carbon is wound on the smaller fusee in the
opposite direction, so that when actuated one cord will be wound off and the other
on. The cord supporting the negative carbon holder is guided over a small pulley
carried by a bar armature attached to ono end of a lever which is suitably pivoted
to the frame. To the opposite end of the said lever is connected an adjustable
spring to act as a counterbalance to the weight of the lower carbon, and to partially
counteract the attraction of two electro-magnets which are provided with wire
helices of comparatively low resistance, and are so arranged that the north pole of
one and the south pole of the other attract the before mentioned bar armature,
whilst their opposite ends face the rotating armature which revolves in close
proximity thereto; another electro-magnet wound. with helices of fine wire having
a high resistance is arranged to face the opposite side of the rotating armature.
The last mentioned magnet should be made adjustable by means of screws, so that
it may be approached to or moved away from the rotating armature as desired.
The electric current passes through the helices of the first mentioned electro-
magnets, which are hereinafter referred to as the electro-magnets, and thence
through the carbons. The fine wire helices of the third electro-magnet herein
before referred to are connected with the two terminals or other equivalent part
of the lamp so as to constitute a branch circuit independent of the main circuit
through the electro-magnets and the carbons.
When an electric current passes through the lamp the electro-magnets will
attract the bar armature, and consequently the roller downwards in opposition to
the spring, thus lowering the lower carbon and separating the carbon points, thereby
establishing the arc. The weight of the upper carbon acting on the periphery of
the larger fusee tends to make the carbons approach each other, but such move-
ment is regulated by the attraction of the electro-magnets on the rotating disc
armature preventing the same from revolving, thus arresting the feeding mechanism
and keeping the carbons separated. As the carbon points are consumed the length
of the are becomes greater and the resistance increases, consequently the current
passing through the fine wire branch circuit will increase, and with it the
magnetism of the magnet having the fine wire helices, until such increased
magnetism counteracts the attraction of the electro-magnets on the disc armature
and leaves the latter free to revolve, thus allowing the carbons to approach each
other, and thereby decreasing the length and lessening the resistance of the arc
until the current in the main circuit and therewith the electro-magnets become
sufficiently powerful to again arrest the disc armature as above described. The
bar armature remains in the position to which it is attracted by the electro-
magnets, and does not move so long as the light is burning, but the disc armature
slowly revolves as the carbons are consumed.
In some cases the lever carrying the bar armature is provided with an adjustable
stop which presses on the periphery of the disc armature, when, the said bar
armature is attracted too far, but the spring connected to the said lever must be so
adjusted that the electro-magnets attract the bar armature only so far as will
enable the said stop just to clear the disc armature, as it is not intended that the
stop should arrest or assist in arresting the disc armature, but only come into
contact with the same when through a sudden increase in the strength of the
current the bar armature is attracted downwards beyond its normal position.
In order to simplify the regulating mechanism above described, we in some
cases dispense with the before mentioned lever, and attach the adjustable spring
directly to the bar armature which moves up and down two guide pins or studs.
A modification of the above arrangement consists in arranging the electro-
magnets to act on the periphery of the rotating armature by means of semi-circular
pole pieces; in this case the electro-magnet on which the fine wire helices are
wound is arranged to face the said semi-circular pole-pieces so as to produce
opposite polarity in the latter, and thereby weaken their attraction on the disc
armature on any increase in the resistance of the arc taking place. The ends of
the said semi-circular pole-pieces are in close proximity to each other, and in some

page_text: cases we attach a movable soft iron piece to one of them, and by regulating the
distance between the said soft iron piece and the pole piece opposite the power of
the electro-magnets, and consequently their attraction on the rotating armature can
be increased or decreased at will, and by arranging the said soft iron piece so as to
touch both pole pieces the power of the said magnets on the disc armature can be
entirely destroyed.
The rotating armature, although hereinbefore referred to as a disc, can be made
in various forms, as, for instance, in the form of a ring or star, as will be well
understood.
In some cases, in addition to the mechanism above described, we arrange an
automatic magnetic brake in connection with the rotating armature, such brake
consisting of a small soft iron lever, so arranged as to be capable of being attracted
to the said armature by the magnetism induced in the latter, and thus to retard or
arrest the same, as the case may be. It will be readily understood that the said
improved brake is applicable to other purposes, for retarding or arresting rotating
bodies when the same have sufficient magnetism induced therein to attract the said
brake. The facility with which such brake is attracted is regulated by a spring.
In single circuit lamps, the electro-magnet having the fine wire helices and
therewith the before mentioned branch circuit may be dispensed with.
Instead of arranging both carbons to move, as above described, the lower carbon
is in some cases made stationary, in such case only one fusee, that from which the
positive carbon is suspended, will be required, the cord on the same being guided
over the pulley carried by the bar armature which is placed below the electro-
magnets so as to be attracted upwards, thereby raising the upper carbon and
establishing the arc.
When the rotating armature hereinbefore described is employed in connection
with a rack or racks for actuating the carbon or carbons, any suitable and known
arrangement of racks may be employed, and the said racks may be arranged to
gear either directly into the pinion on the spindle of the said armature, or they
may be placed in connection therewith through the medium of a train of wheels.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Ernest John Harling and Emil Hartmann in the Great Seal
Patent Office on the 11th February 1882.
ERNEST JOHN HARLING, of Guildford Street, Farringdon Road, and EMIL
"IMPROVE-
HARTMANN, of Compton Street, both in the County of Middlesex.
MENTS IN ELECTRIC LAMPS, PART OF WHICH IMPROVEMENTS ARE APPLICABLE TO
OTHER PURPOSES."
Our said Invention consists in the combination and arrangement of mechanism
for regulating automatically the relative position of the electrodes or points of the
carbons employed in electric lamps, whereby such object is effected in a morė
regular and continuous manner than is the case when arrangements of mechanism
as ordinarily constructed are used. That part of our said Invention which relates
to the arrangement of a brake is also applicable to other analogous purposes.
This Invention consists mainly in the employment of a rotating armature of
soft iron (preferably in the form of a ring or disc) which is placed in connection
with the carbon holders, or one of them, for the purpose of actuating the carbons
or one of them, either by means of toothed wheels and racks attached to both or
one of the said carbon holders, as is customary in electric regulator lamps, as will
be well understood, or the carbon holders or one of them can be suspended by
cords wound off and on drums or fusees, the latter being connected and actuated
by a train of wheels, or in some cases by a worm formed on the spindle of the said
armature and a wheel on the axle of the said drums or fusees.
We will now proceed to describe our Invention when drums or fusees are
employed, as lastly referred to. On the spindle of the rotating armature is a
pinion gearing into a toothed wheel mounted on the spindle of the said fusees; the
cord suspending the positive carbon is wound on the larger fusee in one direction,
and the cord suspending the negative carbon is wound on the smaller fusee in the
opposite direction, so that when actuated one cord will be wound off and the other
on. The cord supporting the negative carbon holder is guided over a small pulley
carried by a bar armature attached to one end of a lever, which is suitably pivoted
to the frame. To the opposite end of the said lever is connected an adjustable
spring to act as a counter balance to the weight of the lower carbon, and to
partially counteract the attraction of two electro-magnets which form part of the
main circuit of the lamp, and are provided with wire helices of comparatively low
resistance, and are so arranged that the north pole of one and the south pole of the
other attract the before mentioned bar armature, whilst their opposite ends face
the rotating armature, which revolves in close proximity thereto; another electro-
magnet wound with helices of fine wire having a high resistance is arranged to
face the opposite side of the rotating armature. The last mentioned inagnet should
be made adjustable by means of screws, so that it may be approached to or moved
away from the rotating armature as desired. In some cases a brake is constructed
and arranged to act on the periphery of the rotating armature, as hereinafter
described.
We will now proceed to refer to Sheet I, of the accompany Drawings in which
the same letters of reference indicate like parts in all the Figures, and from which
the nature of our said Invention will be clearly understood. Figure 1 is a section
of the mechanism of the lamp taken longitudinally through the electro-magnets;
Figure 2 is a view at right angles to the last mentioned Figure of a portion of the
mechanism; Figure 3 is a plan of the said mechanism; Figure 4 shews our novel
brake arrangement combined with the rotating armature, as hereinafter described,
and Figure 5 shows a modification in the arrangement of the mechanism, the electro-

page_text: inagnets N¹, S', and N, S, being shown arranged to act on the periphery of the
rotating armature by means of semi-circular pole-pieces P¹, P, enclosing the same.
The said pole-pieces are made adjustable by being connected to the poles of the
inagnets by means of screws passing through slots, as shown in Figure 5. In this
case the magnet n, s, on which the fine wire helices are wound is arranged to face
the said semi-circular pole-pieces so as to produce opposite polarity in the latter,
and thereby weaken their attraction on the disc or rotating armature on any
increase in the resistance of the arc occurring. We attach a movable soft iron
piece k to one of the said pole-pieces so as to project over the space separating the
poles, and by regulating the distance between the said piece / and the pole piece
opposite, the power of the magnets N¹, S¹, and N, S, and consequently their attraction
on the armature can be increased or decreased at will, and by arranging the said
piece k so as to touch both pole-pieces the power of the said magnets on the
armature can be entirely destroyed, and the more the distance between the piece k
and the pole piece, to which it is not attached, is increased, the greater will be the
influence of the pole pieces P¹, P, on the armature; by these means the lamp can
be adjusted for weaker or stronger currents, as may be required. The arrange-
ment of the magnets and pole-pieces lastly described is illustrated in Figures 5, 6,
and 7. The rotating armature, although shown in the before mentioned Figures in
the form of a disc, can be varied in shape, as will be well understood, one form
which is equally suitable being shown at Figure 8, or it may be in the form of a
ring. The same letters of reference indicate like parts in all the Figures of this
Sheet. A is the rotating armature, and 8* is the spindle thereof; F, f, are the
fusees. On the spindle 8* is the pinion p gearing into the wheel t on the spindle
of the fusees; the lever x, which is pivoted at a¹, has attached to it the bar armature m
carrying the roller r, over which is carried the cord from the smaller fusee f, and s
is the adjustable spring attached to the other end of the lever; N', S¹, and N, S,
are the two first mentioned electro-magnets, and n, 8, is the electro-magnet with
the fine wire helix; Ę is the frame of the apparatus.
The electric current passes through the helices of the electro-magnets N¹, S¹,
and N, S, and thence through the carbons. The fine wire helices of the electro-
magnet n, s, being connected with the two terminals or other equivalent part of
the lamp, constitute a branch circuit independent of the main circuit through the
electro-magnets N¹, S¹, and N, S, and the carbons.
When an electric current passes through the lamp the electro-inagnets N¹, S¹,
and N, S, will attract the armature m downwards in opposition to the spring 8;
such downward movement of the armature m, and consequently of the roller ?,
will lower the lower carbon and thus separate the carbon points, thereby
establishing the arc. The weight of the upper carbon acting on the periphery of
the larger fusee F tends to make the carbons approach each other, but such
movement is regulated by the attraction of the electro-magnets N¹, S¹, and N, S,
on the disc armature A, preventing the same from revolving, thus arresting the
feeding mechanism and keeping the carbons separated. As the carbon points are
consumed the length of the are becomes greater and the resistance increases,
consequently the current passing through the fine wire branch circuit of the
electro-magnet'n, 8, will increase, and with it the magnetism of the said magnet,
until such increased magnetism counteracts the attraction of the electro-magnets
N', S', and N, S, on the rotating armature, and leaves the latter free to revolvė,
thus allowing the carbons to approach each other, and thereby decreasing the
length and lessening the resistance of the arc until the current in the main circuit
and therewith the electro-magnets N', S', and N, S, become sufficiently powerful to
again arrest the disc armature A, as above described. The armature m remains for
a certain time in the position to which it is attracted by the electro-magnets, but
as the length of the arc increases and the strength of the magnetism on the
5 magnets N1, S1, and N, S, decreases, the said armature m gradually moves away
until it rests against the stop h; any further decrease in the current through the
consumption of the carbons will be rectified by the rotating armature, but in the

page_text: event of the rotating armature bringing the carbons too close together they are
again separated by the attraction of the electro-magnets N¹, S¹, and N, S, on
the armature m, the disc armature A slowly revolving as the carbons are
consumed. From the above description it will be readily seen that the mechanism
of lamps constructed in accordance with our said Invention possesses great
sensitiveness, and as magnetic attraction is the only power employed, wherefore
the regulating arrangement is almost free from friction.
In order to simplify the regulating mechanism above described, we in some
cases dispense with the before mentioned lever and attach the spring a directly
to the bar armature m, which moves up and down two pins or studs a, b, attached
to the magnets N', S¹, and N, S, or to the pole-pieces P, P¹, the said pins or studs
passing through apertures in the armature m; this arrangement is shewn in
Figures 6, 7, and 9.
The lever is in some cases provided with an adjustable stop g, which presses on
the periphery of the disc armature A when the armature m is attracted too far.
The spring s must be so adjusted that the electro-magnets N¹, S', and N, S, attract
the armature m only so far as will enable the stop 9 just to clear the disc armature A,
as it is not intended that the stop a should arrest or assist in arresting the disc
armature, but only come into contact with the same when through a sudden increase
in the strength of the current the armature m is attracted downwards beyond its
normal position.
We will now proceed to refer to Sheet II. of the accompanying Drawings, in
which are illustrated a series of modifications of portions of the Invention, as
hereinbefore described and shown in Sheet I. Figure 1 is a view of a lamp
constructed in accordance with our said Invention, in which the pole-pieces of the
magnets N¹, S¹, and N, S, are shown in the form of a ring surrounding the rotating
armature; Figure 2 is a section of the same taken longitudinally through the
centre, showing a worm formed on the axle 8x of the rotating armature for
actuating the wheel t; Figure 3 is a plan of the same; and Figure 4 illustrates a
modification of the brake b; O and Ū are insulating plates; and y, y¹, the pillars
supporting the same; and E is a frame of metal on which is mounted the regulating
mechanism. The magnets N¹, S', and N, S, and n, s, are substantially arranged
and act in the same manner, as hereinbefore described, with the exception that the
pole-pieces P1, P, are shown made in one ring piece P, the same being arranged
concentrically outside of the rotating armature A, which in this case is shown in
the form of a ring mounted on the periphery of a brass disc a, which is mounted
concentrically on the spindle S* pivoted at one end to the frame E, and at the other
end to the bracket i attached to the armature P. The spindle S* is provided with
a worm w, gearing into the teeth formed on the periphery of the wheel t. The
said wheel t, together with the fusees (or drums) F, f, is mounted on a spindle o
pivoted to the two brackets B and B', which are attached to the frame E. "It will
be observed that in this case the spindle c is at right angles with the spindle S*,
whilst when a pinion is employed, as shown in Sheet I. of the accompanying
Drawings, the two spindles are parallel. The fusees F, f, are rigidly attached to
the spindle c, whilst the toothed wheel t turns loosely on the latter, the wheel t
being provided with a ratchet wheel, and the fusee F with a click. This arrange-
ment allows, by turning the key Z, the cord to be wound on the fusees when the
carbons are consumed; R is a conducting rod which is attached at one end to the
frame E, and at the other to the plate U. The carbon holder H* with the positive
or upper carbon slides along the rod R by means of two contact rollers k¹, kl. The
said carbon holder H* and positive carbon C* are suspended by a flexible cord,
(of any suitable nature, such as cord or chain) one end of which is attached ou
the fusee F, and having been wound on the latter, the cord is taken down round a
pulley (attached to H*), when it is again taken up and its other end attached to
an arm v extending from the soft iron armature m, which is attached to levers x
pivoted to the frame at x' and x². A fly lis by preference mounted on the spindle c,
in order to prevent the armature A, a, from acquiring too much momentum ; V is

page_text: a guide roller for the positive carbon; s is an adjustable spring acting on the
levers in opposition to the attraction of N', S¹, and N, S, on the armature m;
g, h, are two adjustable stops, by which the stroke of the armature m, and therewith
the length of the arc, is regulated.
The electric current enters the lamp at D*, and passes' through the rod R,
holder H*, carbons C* and C. to the pillar y¹, and thence through the coils of the
magnets N', S', and N, S, to the terminal D.. The coils of the magnet n, s, form,
as will be well understood, a circuit between D* and D., independently of the
magnets N¹, S, and N, S, and carbons C* and C. In the case of there being no
current the carbons will be together, but on the admission of a current the magnets
N¹, S¹, and N, S, will draw up the armature m, and consequently the holder H* and
As the arc
carbon C*, thereby separating the carbons and establishing the arc.
grows longer owing to the consumption of the carbons the current decreases, and
therewith the magnetism in the magnets N¹, S¹, and N, S, until the said magnets
become too weak to overcome the tension of the spring 8; consequently the
armature m and therewith the lever x will be released until the latter rests against
the stop h; the arc will then have obtained its normal length. If however any
further length of cord is required it will be furnished by the rotation of armature A.
If the same however should feed too much the armature m is in readiness to be
drawn up again, and thus to lengthen the arc and establish normal conditions.
In some cases a modified form of brake bis employed, as shown in Figure 4 of
this Sheet of Drawings. In this case two small pole-pieces d and e extend from
the inner periphery of the pole-piece P into close proximity to the periphery of the
armature A, so as to magnetise the latter sufficiently to attract the brake b:
The arinature A should be as light as possible, and mathematically true on the
spindle 8*.
The worm w is by preference a coarse thread worm, and the wheel t has
corresponding coarse teeth.
The magnets N¹, S¹, and N, S, may be, in addition to their coarse wire coils,
wound also with fine wire coils in the same circuit as the coils of n, 8, so as to render
them more sensitive in the variations of the current; or we in some cases wind the
fine wire coils on the magnets N¹, S¹, and N, S, in a corresponding circuit to those of .
the magnets n, s, and dispense with the latter.
In single circuit lamps the electro-magnet n, s, and therewith the branch circuit
may be dispensed with.
Instead of arranging both carbons to move as above described, the lower carbon
is in some cases made stationary; in such case only one fusee or drum, that from
which the positive carbon is suspended, will be required, the cord on which is
guided over the pulley », the armature m being placed below the electro-magnets
N¹, S¹, and N, S, so as to be attracted upwards, thereby raising the upper carbon
and establishing the arc.
In some cases, in addition to the mechanism above described, we arrange an
automatic magnetic brake in connection with the rotating armature A, as shown
in Figure 5, Sheet I., and such brake consists of a small soft iron lever b pivoted or
hinged to the frame or attachment thereof, the action of such arrangement being as
follows: The rotating armature A, when under the influence of the magnets,
itself becomes an induced magnet, and will attract the lever b, but the attraction is
to a certain degree counteracted by the spring 83. When the magnetism is strong
the rotating armature will attract the brake b, and arrest itself; but when the
current and magnetism become weakened beyond a certain degree the tension of
the spring 8 will overcome the attraction of the disc armature, and will pull the
brake b off the periphery of the same, and leave it free to revolve. A modification
of the said brake b is shown in Figure 4, Sheet II.
When the rotating armature hereinbefore described is employed in connection
with a rack or racks for actuating the carbon or carbons, any suitable and known
arrangement of racks may be employed, and the said racks may be arranged to gear

page_text: ..either directly into the pinion p on the spindle of the rotating armature A, or they
may be placed in connection therewith through the medium of a train of wheels.
Having thus described and ascertained the nature of our said Invention, and the
the manner in which it is to be performed, we would observe in conclusion that we
do not desire to claim any construction or arrangement of fusees or racks, but what
we consider novel and original and therefore claim as constituting the Invention
secured to us by the said hereinbefore in part recited Letters Patent are,―
First. The application in electric lamps of a rotating armature, constructed and
arranged substantially in the manner and for the purposes hereinbefore set forth
and described.
Secondly. The novel brake hereinbefore described, an application of which is
shewn in Figure 4, wherein the magnetism induced in the body to be acted on is
utilised for the purpose of applying the brake, substantially as hereinbefore
described.
Thirdly. The combination and arrangement of the brake b with the rotating
armature A, substantially as and for the purposes hereinbefore set forth and
described.
And, Fourthly. The combination of the electro-magnets N¹, S¹, and N, S, and
n, 8, with the rotating armature A and oscillating bar armature m, substantially as
and for the purposes hereinbefore set forth and described.
In witness whereof, we, the said Ernest John Harling and Emil Hartmann,
have hereunto set our hands and seals, this Tenth day of February, in the
year of our Lord One thousand eight hundred and eighty two.