IMPROVEMENTS IN AND CONNECTED WITH ELECTRIC LAMPS."
Year: 1882

page_text: LETTERS PATENT to Joseph Norman Aronson, of Old Broad Street, in the
City of London, for an Invention of "IMPROVEMENTS IN AND CONNECTED
WITH ELECTRIC LAMPS."
PROVISIONAL SPECIFICATION left by the said Joseph Norman Aronson
at the Office of the Commissioners of Patents on the 24th January 1882.
JOSEPH NORMAN ARONSON of Old Broad Strect, in the City of London. "IM-
PROVEMENTS IN AND CONNECTED WITH ELECTRIC LAMPS."
This Invention has for object improvements in lamps in which several incan-
descing bridges or filaments are combined in one translucent globe or containing
vessel or in which several globes or vessels, each with a single bridge or filament
are combined in one cluster, and in means or apparatus for bringing the said bridges
or filaments of the lamp or of the clusters of lamps successively in the electric
circuit automatically or by hand. When each filament is in a separate globe or
containing vessel I construct each vessel in the form of a tube, and combine several
in a cluster, or I combine several vessels of the ordinary or other suitable form in
a cluster attached to one holder. To prevent accidents from broken globes or
vessels, it is advantageous to cover the globes or vessels with a light wire netting.
I provide each of the several bridges or filaments of such lamps with two independent
terminals, or I connect the whole of the negative ends of the bridges to one common
terminal and provide an independent terminal for the positive end of each bridge.
The terminals may be brought through the globe in any suitable manner; a
convenient arrangement when several bridges or filaments are employed is to
enclose each terminal or connecting wire in a glass tube, which is fused or sealed
around it, and then to arrange the said tubes in a group and fuse or weld them
into a mass, which may be fixed in the globe by fusion or after the manner of a
stopper, or the tubes may be enclosed in a hollow cylinder with one end-closed
through which the tubes pass like the tubes through the tube plate of a locomotive
boiler. Instead of using separate tubes the wires may be passed through a block
or mass of glass and sealed therein.

page_text: The ends of the terminal wires are formed into contact pieces into any of which
the current may be directed. When the direction of the current is to be altered by
hand, I, in one arrangement provide a socket into which the lamp neck will fit,
and in this socket I arrange contact pieces in connection with the leading wires.
When the globe is inserted into the socket in a certain way, say to a certain depth
or in a certain angular position, one of the bridges is in the electrical circuit; when
the globe is inserted in another position, say, to a greater depth or in a different
angular position, another of the bridges is in the circuit and so on, the socket being
80 arranged that the globe may be inserted and securely held in it in as many
positions as there are bridges or filaments. In cases where it is inconvenient for
the globe and socket to be separable one or more sliding pieces may be arranged
on or in the socket, or on or in the lamp in such way that it, or they, is or are in
constant connexion with the generator, and can be put in connection with any one
of the bridges or filaments. An arrangement in which a sliding case is employed
is as follows:-One end of each bridge or filament is connected to a common
terminal and the other end to a separate insulated contact piece on the outside
of the lamp situated below a spring in connection with the leading wire. A case,
ring, or ferrule, provided with slots or grooves corresponding to, but one less in
number than the aforesaid springs can be slid over them. All the springs except
one enter the slots and grooves and are not moved, but the one to which there is
no corresponding slot and groove is forced into connection with the contact plate
below, and completes the circuit to one bridge. When that bridge fails the case
ring or ferrule is drawn back and replaced so as to depress another spring.
In some cases, for instance, when the lamps are to be used in positions difficult
of access, or when it is important that on the failure of a bridge or filament the
darkness should be but momentary, I provide automatic apparatus to bring a fresh
-bridge-into the circuit. Such an apparatus may comprise an electro-magnet wound
with two coils in opposite directions, one coil,-of-small-resistance being in the lamp
circuit, and the other coil of largo resistance being in a shunt circuit round the
bridges or filaments. So long as the circuit is complete an armature within the
range of influence of the magnet is not attracted, as the two coils produce opposite
polarities in the soft iron core which neutralise each other. When the bridge gives
way or becomes inefficient, the current fails or decreases in the one coil, and the
other coil causes the attraction of the armature. When there are but two bridges
in a globe, the armature may complete the circuit through the second bridge directly
by its contact with a terminal so situated as to cut the low resistance coil out of
circuit. In some cases one of the coils may be replaced by a spring or by a
polarised armature or by both. When there are more than two bridges in a lamp,
the armature may work a step-by-step arrangement of any suitable description,
each step bringing a fresh bridge into circuit upon the failure of the previous one.
The step-by-step motion may be mounted on the lamp or on the socket or may be
at a distance from both and be electrically connected to them by conductors.
Increase or decrease of current from causes exterior to the lamp will not produce
any motion of the armature, which is adjusted so as not to make its stroko
until the lamp current has altered very considerably with relation to the shunt
current.
Instead of two coils being wound on one core, they may be wound on two
separate cores so situated with respect to the armature that their influences
neutralise each other.
I
In some cases a differential solenoid or solenoids may be substituted for the
electro-magnet. These solenoids may have a common soft iron core or two cores
coupled together, or one solenoid may be movable with respect to the other;
prefer however to wind them in opposite directions on one bobbin and provide
them with one common soft iron core. When a Lidge or filament of the lamp
becomes inefficient the shunt coil will draw in the soft iron core which may be
provided with contact pieces arranged to couple the bridges or filaments to the
leading wire in succession. To this end the core may conveniently be furnished

page_text: with an arm or plate or piece which in its movement comes successively in contact
with light springs forming the terminals of the bridges or filaments and compresses
them. As soon as a fresh circuit is established the second coil will be excited and
the motion of the core arrested. When mercurial contacts are admissible the
terminals of the bridges or filaments may be sealed at successive heights into a
bent tube in communication with an elastic vessel containing mercury and subject
to pressure from the solenoid corc. When a bridge or filament fails the core will
force the mercury over the bend of the tube and raise its level in the other leg to
reach the next succeeding terminal. By providing the core with helical grooves or
projections, it may have a circular as well as an endwise motion imparted to it, or
it may serve to impart a circular motion to a correspondingly grooved hollow piece
or nut. This circular motion may be communicated to the lamp itself, or to the
socket, or to a commutator, to effect the movement of the contact pieces. When it
is desired to keep the apparatus within limits of size that do not admit of the
electro current being utilised as the motive force, a coiled spring or other suitable
reservoir of power may be employed to move the contact pieces, and its motion may
be regulated by a differential electro magnet or solenoid acting on an escapement
or a fly.
When several lamps are arranged in series, there will be a great increase of
current in the shunt circuit on the failure of a bridge or filament, and consequently
a shunt circuit of very high resistance may be employed. Under theso conditions
I combine a small electro magnet with one terminal of each bridge or filament and
I place opposite to it an armature provided with a spring capable of holding it in
two positions (like the spring of a pocket penknife) either in contact with or at a
short distance from the magnet. I connect the first bridge or filament direct to the
leading wire and I make a shunt circuit round it, which circuit includes tho
armature of the second magnet or a part of it, a high resistance magnet coil, and
the second bridge or filainent. When the first bridge or filament fails, then an
increased current passes through the second magnet, thus attracting its armature,
which comes up against a contact piece and furnishes a direct path for the current
to the bridge or filament past the high resistance coil. The third bridge or filament
is similarly connected to the second, and the fourth to the third and so on. If
found desirable in place of the directive force of the current, the heating power
may be employed to bring another bridge or filament into circuit on the failure of
the preceding one. According to one arrangement that I employ when I adopt
this method of working I connect all the negative ends of the bridges or filaments
to a common terminal, and I connect all the positive ends to independent terminals.
The first positive terminal I put in direct communication with the leading wire,
and also in communication with a spring forming part of a shunt circuit through
the second bridge or filament. Between the said spring and the terminal of the
second bridge or filament 1 interpose a high resistance of such a nature that when
the first bridge or filament fails and the whole or greater part of the current
traverses the said high resistance, the whole or a portion of it or of its casing,
vehicle support or attachment will burn, melt, or evaporate and allow the spring to
move, and make good metallic contact with the terminal. The interposed resistance
may be constructed in many ways, such for example as a coil of fine wire embedded
in wax, or made from an easily oxidisable metal or as a prison or crystals of an alloy
of low conducting power and low melting point. I connect the third terminal to
the second, and the fourth to the third, and so on in a similar way. The power of
the spring to make its movement towards the terminal may be supplemented by
constructing it of two metals having different co-efficients of expansion under heat.
As is well understood such a spring will suffer a change of form under the heating
action of the current and its free portion will move. In this case if it only make
frictional or elastic contact with the interposed resistance, the latter need not melt.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Joseph Norman Aronson in the Great Seal Patent Office on the
24th July 1882.
JOSEPH NORMAN ARONSON of Old Broad Street in the City of London. Iм-
PROVEMENTS IN AND CONNECTED WITH ELECTRIC LAMPS.
This Invention has for object improvements in lamps in which several incan-
descing bridges or filaments are combined in one translucent globe or containing
vessel or in which several globes or vessels, each with a single bridge or filament
are combined in one cluster, and in means or apparatus for bringing the said
bridges or filaments of the lamp or of the clusters of lamps successively into the
electric circuit automatically or by hand. When each filament is in a separate
globe or containing vessel I construct each vessel in the form of a tube and combine
several in a cluster, or I combine several vessels of the ordinary or other suitable
form, in a cluster attached to one holder.
To prevent accidents from broken globes or vessels it is advantageous to cover
the globes or vessels with a light wire netting. I provide each of the several
bridges or filaments of such lamps with two independent terminals, or I connect the
whole of the negative ends of the bridges to one common terminal and provide an
independent terminal for the positive end of each bridge. The terminals may be
brought through the globe in any suitable manner; a convenient arrangement
when several bridges or filaments are employed is to enclose each terminal or
connecting wire in a glass tube, which is fused or sealed around it, and then to
arrange the said tubes in a group and fuse or weld them into a mass, which may
be fixed in the globe by fusion-or-after-the-manner of a stopper, or the tubes may
bo enclosed in a hollow cylinder with one end closed through which the tubes-pass-
like the tubes through the tube plate of a locomotive boiler. Instead of using
separate tubes the wires may be passed through a block or mass of glass and sealed
therein.
The ends of the terminal wires are formed into contact pieces into any of
which the current may be directed. When the direction of the current is to be
altered by hand I, in one arrangement, provide a socket into which the lamp neck
will fit, and in this socket I arrange contact pieces in connection with the leading
wires. When the globe is inserted into the socket in a certain way, say to a certain
depth or in a certain angular position, one of the bridges is in the electrical circuit;
when the globe is inserted in another position, say to a greater depth or in a
different angular position, another of the bridges is in the circuit and so on, the
socket being so arranged that the globe may be inserted and securely held in it in
as many positions as there are bridges or filaments. In cases where it is incon-
venient for the globe and socket to be separable one or more sliding pieces may be
arranged on or in the socket, or on or in the lamp in such way, that it, or they, is
or are in constant connection with the generator, and can be put in connection
with any one of the bridges or filaments. An arrangement in which a sliding case
is employed is as follows:-One end of each bridgo or filament is connected to a
common terminal and the other end to a separate insulated contact piece on the
outside of the lamp situated below a spring in connection with the leading wire.
A case, ring, or ferrule provided with slots or grooves corresponding to but one
less in number than the aforesaid springs can be slidden over them. All the springs
except one enter the slots and grooves and are not moved, but the one to which
there is no corresponding slot or groove is forced into connection with the contact
plate below, and completes the circuit to one bridge. When that bridge fails the
case, ring, or ferrule is drawn back and replaced so as to depress another spring.
In some cases, for instance when the lamps are to be used in positions difficult of
access, or when it is important that on the failure of a bridge or filament the

page_text: darkness should be but momentary, I provide automatic apparatus to bring a fresh
bridge into circuit. Such an apparatus may comprise an electro magnet wound
with two coils in opposite directions, one coil, of small resistance being in the lainp
circuit, and the other coil, of large resistance being in a shunt circuit round the
bridges or filaments. So long as the circuit is complete an armature within the
rango of influence of the magnet is not attracted, as the two coils produce opposite
polarities in the soft iron core which neutralize each other. When the bridge gives
way or becomes inefficient the current fails or decreases in the one coil and the
other coil causes the attraction of the armature. When there are but two bridges
in a globe the armature may complete the circuit through the second bridge directly
by its contact with a terminal so situated as to cut the low resistance coil out of
circuit. In some cases one of the coils may be replaced by a spring or by a,
polarised armature or by both. When there are more than two bridges in a lamp
the armature may work a step-by-step arrangement of any suitable description,
each step bringing a fresh bridge into circuit upon the failure of the previous one.
The step-by-step motion may be mounted on the lamp or on the socket or inay be
at a distance from both and be electrically connected to them by conductors.
Increase or decrease of current from causes exterior to the lamp will not produce
nny motion of the armature, which is adjusted so as not to make its stroke until
the lamp current has altered very considerably with relation to the shunt current.
Instead of two coils being wound on one core, they may be wound on two
separate cores so situated with respect to the armature that their influences neutralize
each other.
In some cases a differential solenoid or solenoids may be substituted for the
electro magnet. These solenoids may have a common soft iron core or two cores
coupled together or one solenoid may be moveable with respect to the other. I
prefer, however, to wind them in opposite directions on one bobbin and provide
them with one coinmon soft iron core. When a bridge or filament of the lamp
becomes inefficient the shunt coil will draw in the soft iron core which may be
provided with contact pieces arranged to couple the bridges or filaments to the
leading wire in succession.
When it is desired to keep the apparatus within limits of. size that do not admit
of the electric current being utilized as the motive force a coiled spring or other
suitable reservoir of power may be employed to move the contact pieces, and its
motion may be regulated by a differential electro magnet or solenoid acting on an
escapement or a fly.
When several lamps are arranged in series, there will be a great increase of
current in the shunt circuit on the failure of a bridge or filament. Under these
conditions I combine a small electro magnet with one terminal of each bridge or
filament and I place opposite to it an armature provided with a spring capable of
holding it in two positions (like the spring of a pocket knife) either in contact with
or a short distance from the magnet. I connect the first bridge or filament direct
to the leading wire and I make a shunt circuit round it, which circuit includes the
armature of the second magnet or a part of it, a high resistance magnet coil, and
the second bridge or filament. When the first bridge or filament fails, then an
increased current passes through the second magnet thus attracting its armature,
which comes up against a contact piece and furnishes a direct path for the current
to the bridge or filament past the high resistance coil. The third bridge or filament
is similarly connected to the second, and the fourth to the third and so on.
found desirable in place of the directive force of the current, the heating power may
be employed to bring another bridge or filament into circuit on the failure of the
preceding one. According to one arrangement that I employ when I adopt this
inethod of working I connect all the negative ends of the bridges or filaments to a
common terminal, and I connect all the positive ends to independent terminals.
The first positive terminal I put in direct communication with the leading wire,
and also in communication with a spring forming part of a shunt circuit through
the second bridge or filament. Between the said spring and the terminal of the
If

page_text: second bridge or filament I interpose a high resistance of such a nature that when
the first bridge or filament fails and the whole or greater part of the current
traverses the said high resistance, the whole or a portion of it or of its casing,
vehicle, support or attachment, will burn, melt, or evaporate and allow the spring
The interposed
to move and make good metallic contact with the terminal.
resistance may be constructed in many ways, such for example as a coil of fine
wire embedded in wax, or made from an easily oxidisable metal or as a prism or
crystals of an alloy of low conducting power and low melting point. I connect
the third terminal to the second, and the fourth to the third, and so on in a similar
way. The power of the spring to make its movement towards the terminal may
be supplemented by constructing it of two metals having different co-efficients of
expansion under heat. As is well understood such a spring will suffer a change of
In
forin under the heating action of the current and its free portion will move.
this case if it only make frictional or elastic contact with the interposed resistance,
the latter need not melt.
Referring to the accompanying Sheet of Drawings Fig 1 illustrates a method
according to my Invention of scaling platinum and other conductors into the globes
or containing vessels of incandescent electric lamps, and Fig 2 is a plan of the
same.
A is the globe, and through the end B, which may be more or less arched, there
pass a number of glass tubes CC scaled into their places. The outer ends of these
tubes pass completely through the end of the globe and project a little on the
outer side. Their inner ends are sealed around the platinum conductors which
pass through them and the outer ends may also be similarly sealed thus producing
a double joint. Each platinum conductor may pass through a separate tube or
both conductors for one filament may be included within one tube.
Fig. 3 is a vertical central section-through an incandescence lamp containing
three filaments. Fig 4 is a horizontal section in line ab-of-Fig 3. of such a
lamp wherein any one filament can be put into the electric circuit. Fig 5 is
similar section of a lamp so arranged that one, two or more filaments can be included
within the circuit at a time. DD are the loops or filaments fixed to metallic
conductors in the usual way. Each of these conductors is connected at its other
end to a contact piece E attached to the lamp globe, or to a casing or extension F,
in connection therewith. This casing or extension is shewn in the Drawings ns
partly surrounding the neck of the globe or containing vessel A, but it also might
be a plug or bush fitted within it. G G' are two terminals or contact pieces
fitted within a case or nozzle H, and connected respectively to the positive and
negative main conductors or leads. In the Drawing the contact piece G' is shewn
connected to the ring G, and the piece G to the plate G³ and the whole is made
in the form of a screw plug that can screw into a socket, and in so doing make
the necessary connections, it is evident however that the part H might be a ring
or ferrule and the part F be made to carry the lamp, and that other means might
be used to connect the pieces G G' to the main leads. In Fig. 4 the contact
pieces E are symmetrically disposed round the circle, and the pieces G G₁ are not
long enough to be in contact with two of the pieces E E at a time. In Fig 5 the
pieces GG are shewn large enough to embrace one, two, or more, of the pieces E E.
By the former arrangement the filaments may be brought into circuit in succession
as consumption or breakage occurs, or filaments of different resistances and radiating
areas may be brought into circuit according to requirement. In the latter arrange-
ment the number of filaments included in the circuit may be varied according to
the amount of light required. In both cases the direction of the current through
the filaments can be reversed at will.
Fig. 6 is a central vertical section and Fig 7 an elevation at right angles to Fig 6
of another arrangement according to my Invention by which several incandescing
filaments can be brought into circuit successively or simultaneously. In this case
the metallic conductors to which the negative ends of the filaments are attached
are all connected to one common terminal G³, while those to which the positive

page_text: ends are attached are connected to separate rings E E. H is a ring or ferrule in
connection with the positive lead or main, and as it is slidden upwards it makes
contact with the pieces E E in succession.
Figs 8 and 9 are vertical and horizontal sections of another arrangement whereby
the several incandescing filaments enclosed within one globe or containing vessel may
be put successively (one at a time) into the electric circuit. All the negative ends
of the filaments are connected to a common terminal G³, and each of the positive
ends to a separate contact plate E. The springs G' G² are in electrical connection
with the positive lead or main, and when allowed to assume their natural attitudes
stand opposite to, but clear of the contact plates E E. H is a ring or ferrule in
which there are grooves cut, one less in number than the number of the springs G
When the ferrule is forced over the springs it follows that one of them is pushed
up against the corresponding contact piece E.
Fig 10 is a vertical section and Fig 11 is an elevation at right angles to Fig 10
of an arrangement according to my Invention whereby a second incandescing
filament may be automatically brought into the electric circuit upon the failure of
the first. These filaments may be in the same globe or containing vessel or in
separate ones. Fig 12 is a diagram illustrating the connections. Referring to the
diagram D D' are two incandescing filaments with both their negative ends con-
nected to a common terminal. A is an electromagnet wound with a single coil,
and provided with an armature B on a spring arm C. The arm also carries a
contact piece E which, when the magnet is not excited stands against tlio contact
piece F. Tracing the course of the current it will be seen that the positive lead is
divided at the point G, and, with the parts in the positions shown, there are two
paths for the current. The first is round the electro magnet A, through the
filament D and away to the negative lead or inain. The second is from G to the
spring arm, through the two contact pieces F E, and through the second filament
to the negative lead. As soon, however, as the current flows the magnet A attracts
its armature B separating the contacts E and F and breaking the second circuit.
Should the first filament fail, however, the armature will return completing the
second circuit and the second filament will be traversed by the current.
This arrangement is equally applicable when it is desired to provide more than
one filament in reserve. Fig. 13 is a diagram illustrating it in connection with
four filaments, and Fig 14 is a view of the electromagnet to a larger scale. This
magnet is essentially the same as that shewn in Figs. 10 and 12 but is arranged so
as to be self contained. The contact piece F is carried on a bracket C¹ which is
insulated from the magnet core and from the spring arm C. Each movable contact
piece E is connected to the main positive lead G³, and the positivo end of each
filament, except the first, is connected to a contact piece F. The magnets A are
included in a circuit traversed by the return current from the filament in action,
except it be the last, to the negative lead. The action of this apparatus is as
follows. When the first or left hand filament is in action the current after leaving
it passes round all the magnets A, and consequently their armatures are attracted
and the contacts E, F, separated so that the remaining filaments are cut out of
circuit. If the first filament break all the armatures will rise and the current flow
momentarily through all the remaining filaments: The current from the second
filament however, will draw down the armatures of the second and third magnets
and cut the third and fourth filaments out of circuit, and so on. In practice the
magnets A may be combined with the lamp in many ways. The plan shewn in
Figs. 10 and 11 may be followed and the magnets ranged one over the other to the
required number.
Fig. 15 is a vertical section of a lamp constructed according to this part of my
Invention. It contains six filaments, and the same number of electro magnets A A.
There is one more magnet than is actually necessary but it allows the lighting to
be commenced with any desired filament. The magnet cores are six arms radiating
from a central stud which also serves to carry the spring arms C. The contacts F
are fixed to the case. G G¹ are the springs at which the current enters and leaves.

page_text: The course of the current can be best followed by reference to Fig. 13, which is
hereinabove explained.
Fig. 16 is a vertical section and Fig. 17 a part vertical section at right angles to
Fig. 16 of a step-by-step apparatus according to my Invention more particularly
applicable in cases where the apparatus is not attached to the lamp but is situated
at a distance from it and electrically connected to it by conductors. H is a soft
iron core wound with two coils traversed by the current in opposite directions.
I is a coil of small resistance in the lamp circuit and J a shunt coil between the
main leads and having a resistance several times greater than that of an
incandescing filament in order to prevent waste of current. If however tho
filament of the next lamp be included in the shunt circuit there is no reason
why it should be of any greater resistance than the main coil. K is an armaturo
loose on the shaft L which is carried in bearings M M. In its normal position
this armature is held by a light spring (not shewn in the Drawings) away from
the core. The armature carries an arm provided with a pawl N engaging with the
ratchet wheel O to which the rotating contact maker P is attached. This contact
maker may be of any ordinary construction.
In the illustration it is shewn as being made of segments of conducting material
separated by non conducting strips and connected alternately to the positive and
negative leads by the brackets M M. So long as the particular filament, to which
the apparatus for the tino being is connected is efficient the two currents passing
through the coils will practically neutralise each other whether they be strong or
weak, but if the filament be ruptured one coil, I, will cease to operate and the
other, J, will cause the armature to make a stroke and rotate the contact maker to
bring a second filament into circuit. It is evident that instead of a fixed core and
an armature a movable core connected to the pawl N might be employed.
Fig. 18 is a vertical section of an apparatus according to my Invention for
bringing a second incandescent filament-into-the-electric circuit upon the failure of
the one previously in operation, wherein the motive power required to effect the
change is provided by a coiled spring, the current merely acting as a regulator to
its motion. I and J are two differential coils as in the previous Figure; they have
a movable hollow soft iron core H, which normally stands on the fly P and presses
it down until it engages with the fixed stud Q R is the coiled spring; it is
attached at one end to the spindle S and at the other end to the case. The spindle S
carries a spur wheel S' gearing into a pinion S which, through the spindle S³ and
wheels S*S* drives the fan P. This fan is obliged to rotate with the wheel S*,
but is forced away from it by a light spring between the two. The effect of this
is that as soon as the fan is relieved of the weight of the core H it rises over the
stop and commences to rotate. The action of the apparatus is as follows;-all
the negative ends of the filaments are supposed to be connected to a common.
terminal not shewn, and all the positive ends terminate in springs touching the
contact maker T, which is of non conducting material for the greater portion of its
circumference, say about seven-eighths of the whole. The main current traverses
the coil I, then is led to the binding post U and up the spindle to the contact
maker, and through the spring that is in contact with the conducting segment to
one filament and through it to the negative lead. At the same time the shunt
current circulates through the coil J, and practically neutralizes the influence of
the inner coil. When the filament becomes inefficient the core is raised by the
action of the outer coil, the fan released and the spindle rotates until another
filament is brought into circuit.
When several lamps are arranged in series there will be a great increase in the
shunt circuit of any particular lamp, especially in the earlier part of the series on
the failure of a filament in that lamp.
Fig. 19 is a vertical section and Fig. 20 a sectional plan of an arrangement
according to my Invention suitable, under such conditions, for bringing a second
filament into action upon the failure of the one in use.
Fig. 21 is a diagrammatic view illustrating the connections. The lamp is shewn

page_text: with six filaments and six electro magnets, which is one more than is actually
required, but is introduced in order that any desired filament may be placed in
circuit in the first instance. Referring to the diagram it will be seen that
magnet A' has been short circuited by the loop passing round it and that
filament B¹ is directly connected to the positive and negative mains. At the same
time there is a shunt circuit through the magnet coil A² and the filament B³, and
a subsidiary shunt circuit round the magnet A³ and filament B³ and so on. As the
current that is diverted through the shunt circuit produces no useful lighting effect
it is necessary that the coils A2, A3, A4, etc., should each have a resistance several
times greater than that of an incandescent filament. When the filament B¹
becomes inefficient there is a greatly increased current, if the lamps be in series,
through the coil A' and this increase effects the automatic short circuiting of the
coil, and the delivery of the full current to the next filament B. Each of the coils
is wound upon a soft iron core which it magnetises, but not to a sufficient extent
to attract its armature, which is normally retained by a little spring catch c.
When the magnetic power increases beyond a determined amount the armature is
drawn up to the magnet forcing the toe of its carrying arm off the spring catch c
which immediately slips under the inclined edge c' and maintains the armature in
its forward position. The motion brings the contact piece D against the piece E
and thus opens a new path for the current which instead of going from c¹ round
the coil A to the contact E, now goes, for the greater part, direct to the same point
through the arın carrying the armature. G G are the terminals of the lamp.
Fig 22 is an explanatory diagram, Fig. 23 a detail view, and Fig. 24 a vertical
section of an arrangement whereby the heating power of the current inay be made
available according to my Invention to bring another filament into circuit on the
failure of the preceding one. Referring to the diagram B', B2, B³, B', are four
filaments, all connected at their negative ends to a common conductor which
includes a magnet coil in all respects similar to that shewn in Fig 13 and provided
like it with two contact pieces. The positive end of the first filament is connected
to the conductor G. The positive end of each of the other filaments is connected
to a spring H, Figs 22, 23, 24, which has a natural tendency to press against the
conductor G, but is held or tied back by a loop or tie I of a material that will be
destroyed by the passage of a powerful current. Each of these ties is also fixed to
a conductor J in connection with the movable contact on the magnet. The fixed
contact is coupled to the positive conductor G. R, R¹, R³, are resistances to
regulate the heating current. In the positions shewn the current starts at C,
passes through the filament B', and round the magnet coil A to the negative lead. If
now the filament B¹ become ruptured the magnet will cease to attract its armature
and the two contacts E, F, will touch each other. Thereupon a new path will bo
opened to the current, it will pass from the main conductor G to the contacts F, E,
and thence to the conductor J. At this point it will divide through the three
links I and the three filaments, the greater part however going momentarily
through the first link and the filament B. The effect of this is that the link is
almost instantaneously destroyed and the spring moves into good contact with tho
conductor G, putting the filament B into the direct circuit and breaking the
subsidiary circuit at E, F. The spring of the magnet A must be so regulated
that it will not break the circuit at E, F, until the new connexion at H is
established.
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 as secured to me under the Letters Patent herein-
before in part recited is ;-
1. In an incandescence electric lamp comprising more than one independent
filament or bridge introducing the conductors for the said filaments or bridges into
the globe or containing vessel through tubes which project beyond the globe or
containing vessel substantially as described and illustrated.
2. The improved incandescence electric lamp with independent filaments or bridges

page_text: able to be put successively into circuit as shewn in and described with reference to
Figs 3, 4 and 5 of the Drawings.
3. In an incandescence electric lamp comprising more than one independent
filament or bridge, the use in combination with one or more terminals for each
bridge or filament, of a sliding or movable piece such as H whereby one or more of
the said filaments or bridges may be put into the electric circuit as described with
reference respectively to Figs 6 and 7, and to Figs 8 and 9 of the Drawings.
4. In an incandescence electric lamp comprising two independent filaments or
bridges the arrangement and combination of parts constituting the automatic
apparatus for bringing the second bridge or filament into the electric circuit upon
the failure of the first as described with reference to and shewn in Figs 10 and 11
of the Drawings.
5. In an incandescence electric lamp comprising more than two filaments or
bridges the use for the purpose of putting the said filaments or bridges into the
electric circuit successively as failure occurs of a number of electro magnets or
solenoids equal to or one less in number than the filaments or bridges and so
arranged that the current passing through the filament or bridge in action circulates
round all the electro magnets or solenoids corresponding to the filaments or bridges
that have yet to come into action substantially as described and illustrated.
6. In an incandescence electric lamp comprising more than one filament or
bridge, the use for the purpose of bringing (when a filament or bridge has failed) a
fresh filament or bridge into the clectric circuit, of a magnet or solenoid wound
with two coils, one of which is in circuit with the bridge or filament that is in
action and the other in a shunt circuit, the arrangement being such that variations
in the current due to causes exterior to the lamp shall not put the apparatus in
action substantially as described.
7. In an incandescence electric lamp comprising more than one filament or
bridge the use, for the purpose of bringing (when a filament or bridge has failed) a
fresh filament or bridge into the electric circuit, of-a-coiled spring or equivalent
reservoir of power controlled by a magnet or solenoid substantially as described:---
8. In an incandescence electric lamp comprising more than one filament or
bridge the use, for the purpose of bringing the said filaments or bridges successively
into the electric circuit of electro magnets or solenoids equal in number to or one
Jess than the number of the filaments or bridges and so arranged that the magnet
or solenoid corresponding to the bridge or filament in action is short circuited,
while the remaining magnets or solenoids form derived eircuits to the one in action
substantially as described with reference to the diagram Fig 21 of the Drawings.
9. The improved automatic apparatus for bringing the bridges or filaments of an
electric incandescence lamp, comprising more than one filament or bridge,
successively into the electric circuit as failure occurs constructed arranged and
operating substantially as described with reference to Figs 19 and 20 of the
Drawings.
10. In an incandescence electric lamp comprising more than one filament or
bridge, the application and use for the purpose of bringing the said filaments or
bridges successively into the electric circuit, of a substance that will burn, melt or
evaporate under the action of the current substantially as described and illustrated.
In witness whereof I the said Joseph Norman Aronson have hereunto set
my hand and seal this Twenty fourth day of July in the year of our
lord One thousand eight hundred and eighty two.
JOSEPH NORMAN ARONSON. (L.S.)