Improvements in and appertaining to the Working of Incandescence Electric Lamps.
Year: 1898

page_text: Date of Application, 27th July, 1893
Complete Specification Left, 27th Apr., 1899-Accepted, 17th June, 1899
Date of Application, 7th July, 1093
Complete Specification Left, 27th Apr., 1899-Accepted, 17th June, 1899
PROVISIONAL SPECIFICATION.
Improvements in and appertaining to the Working of Incandescence
Electric Lamps.
I, DONALD MACLAGAN, of Rooksbury, Gresham Road, Staines, in the County
of Middlesex, Electrical Engineer, do hereby declare the nature of this invention
to be as follows:-
My invention relates to certain improvements in and appertaining to the working
of incandescence electric lamps; and applies to those in which a non-conducting
substance or material under normal conditions is used as a luminous filament,
slab or bar, the primary heating necessary to afford sufficient conductivity being
externally applied, preferably from the electric current derived from the circuit.
The object is to produce automatically a continuous luminosity in a single lamp
or a number of lamps, or an alternate luminosity in a number of lamps.
I call the heating circuit in all cases, the "preliminary heating circuit," since
it is only required to primarily heat the filament or equivalent, the conductivity
thus being raised, and the current flowing freely rendering it luminous.
In order to light one filament or its equivalent I employ one electro-
magnet or solenoid included in the preliminary circuit and a second
magnet or solenoid in the lighting circuit, which passes through the filament
or equivalent aforesaid. A single pivotted armature is common to both magnets
or solenoids, (in the latter case a pivotted lever is coupled to the core common to
both solenoids). The magnets or solenoids may be alternately or completely cut
out of circuit during the action of the lamp, for instance, when the filament or
equivalent becomes sufficiently heated to be incandescent, the preliminary circuit
is cut out by the magnet or solenoid included in the primary or filament circuit,
the pivotted armature making suitable contacts therefor. By means of swinging
contacts with insulated spaces, the other magnet or solenoid may be cut out of
the primary circuit, which is then maintained through the filament or its equiva-
lent alone. Thus the energy absorbed by one or both magnets or solenoids may
be saved during the maintenance of the light.
In cases where two or more filaments or equivalents are used in one lamp, they
are placed in parallel circuit, with or without a single resistance in series, with
the main circuit. When such a number of filaments or the like are so arranged,
they may be enclosed by a single cage, reticulated hood, or the like of metal, or
alloy of high electrical resistance, so that when the preliminary heating current
passes, sufficient heat is generated to raise the filament or the like to a temperature
allowing of the passage of the primary current which raises it to incandescence.
Said preliminary current generally heats up a filament to conducting point by
selection; namely that of highest initial conductivity, and by means of the magnets
or solenoids herein before referred to, the preliminary circuit is broken, and the
primary established through the refractory but now conductive filament. The
other filaments or equivalents in the same circuit will remain neutral, being
practically of negligible conductivity unless heated.
This arrangement being sometimes not applicable to the conditions of working,

page_text: it is necessary to place the two electromagnets or solenoids in such a manner th
a step by step or like mechanical device may be operated by them.
In one single lamp or globe a single preliminary heating cage, hood or the li
I may place any number of filaments or equivalents, all arranged in parallel, bu
so connected to the automatic pendulous contacts herein before described that any
one may be operated separately or alternately. And further, I use in such an
arrangement a cage hood or the like adapted to each filament, and each coupled
to the preliminary heating circuit. If one only is used, the magnets or solenoids
are arranged to bring into action the various filaments in rotation, either according
to their degree of conductivity by selection, or by means of a graded contact device
operated thereby. The filaments in the latter case are caused to travel in the
same manner as the cartridges in a magazine rifle. Or if a separate cage or hood
connected to the preliminary circuit be used for every filament, each may be
separately operated or cut out as the case may be by the magnets or solenoids,
and the pivotted lever herein before described.
I may dispense with both magnets and solenoids, and use three switch wires,
coupled to the main circuit through an ordinary switch with a time switch of any
known type or form interposed in the preliminary circuit, so that a predetermined
interval of time may elapse after closing the circuit so that said preliminary
heating circuit may have time to act upon the filament or its equivalent before
being cut off. When the main switch is opened, the return action is caused to
restore the position of the time switch to its normal position.
The essential feature of my said invention is in the control of the preliminary
heating current and the primary or lighting current by an automatic arrangement,
whether one or more filaments be used separately or included in one lamp, and
economising energy by such arrangement."
FREDK. WALKER,
73, St. Stephen's Road, Upton Park, London, E.,
Agent for the Applicant.
Improvements in and appertaining to the Working of Incandescence
Electric Lamps.
I, DONALD MACLAGAN, of Rooksbury, Gresham Road, Staines, in the County
of Middlesex, Electrician, 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:-
My invention relates to certain improvements in and appertaining to the work-
ing of incandescence electric lamps, and is applicable to those in which a non-
conducting substance or material under normal conditions is used as a filament,
slab, or bar, to become luminous subject to certain conditions of raising the
temperature by the action of an auxiliary electrical current passing through a
separate circuit. The electrical energy absorbed by this primary heating circuit
is derived from the main leads and having raised the temperature of the filament
or its equivalent to the point of conductivity may be cut off. To effect this auto-
matically, and produce a continuous luminosity in a single lamp or an alternate
luminosity in a number of filaments by such automatic action is the object of
my invention.
-
In order that my invention may be clearly understood I have appended the
accompanying four sheets of drawings in which Figure 1 Sheet 1 is a diagrammatic

page_text: view of an automatic switch with two magnets (or solenoids) and Figure 2 is a
modification in which one magnet is employed. Figure 3 Sheet 2 illustrates the
lighting of the filaments by natural selection by means of a heating circuit.
Figure 4 Sheet 3 represents a step by step arrangement for the operation of one
filament out of a group. Figure Sheet 4 is a diagram illustrating the use of a
time switch for cutting out the preliminary or heating circuit. In all modifica-
tions I desire to imply the substitution of solenoids wth sliding cores for the
electro magnets chosen for purposes of illustration, and where practicable similar
letters of reference indicate corresponding parts throughout the several views.
In carrying my invention into effect I employ in all cases a heating circuit, to
render the filament or filainents luminous by increasing the conductivity thereof
as aforesaid, the free passage of the electric current through said filament main-
taining said conductivity and consequently the luminosity; and in all cases of
reference in the following description I call the heating circuit, the "preliminary
heating circuit since its effect is transient. In order to light one filament F
Figure 1 Sheet 1 or its equivalent, I employ one electro magnet (or solenoid) M in
partial connection with the preliminary circuit" and a second magnet (or
solenoid) M in partial connection with the lighting circuit, the complete circuits
in both magnets (or solenoids) being effected by certain moveable contacts herein-
after to be described. A pivotted armature A, fulcrummed at p is common to both
magnets M M (and in the case of using solenoids would carry the cores thereof).
Each end of said armature A is insulated from the body thereof, so as to form a
switch or contact arm, and the action is as follows, that is to say :-
"
::
In the normal condition the armature A makes contact at its upper insulated
end with plates c d, and when the switch S is closed the circuit is established
through said plates cd, the coils of the magnet or solenoid M and the heating
wire or preliminary circuit" H, the terminals being shown by B B and the arma-
ture A is attracted towards M, and contact plates ie are thereby connected. The
heating wire or preliminary circuit" H is heated by the passage of the current,
and the filament or the like is thus rendered conductive, and a separate circuit
is established, viz.-through the coils of the electromagnet (or solenoid) M' and
also through the neutralizing coils on M shown by thick lines, thence by s to and
through to B, which for purposes of illustration may be the return or lead.
The electromagnet (or solenoid) M is demagnetized, and the armature A is
instantly drawn over to M' opening the heating circuit at the contact plates c d
and also opening the neutralizing coils at plates ie and shorting through a
resistance of suitable calibre the coils of M by coupling the contact plates gh,
the plate f being simultaneously joined in the circuit to maintain the current
through the filament F. The resistance R has a dual function, insomuch that in
the first instance it regulates the current so as to allow sufficient to pass around
the coils of 1 to retain the armature A and the consequent contact points until
the circuit is broken by the light being switched off, and secondly, it forms part
of the choking resistance incidental to this type of electric lamp. The energy
absorbed by the magnet or solenoid M is thus saved during the maintainence of the
light.
In cases where a second electro magnet (or solenoid) may obviously he dispensed
with I may employ an alternative device shown by Figure 2. Here a single
electro magnet (or solenoid) f is adjacent to an armature A pivotted at 7, which,
by means of an insulated contact extension t establishes the circuit, when in its
normal position from terminal 31 (+) to contacts c d and through the coils of M,
the "preliminary circuit" H being completed when the switch S is closed. The
filament F, previously of negligible conductivity, becomes heated, and the second
circuit is established through the coils of the magnet (or solenoid) M by leads s
and m.
The armature A is drawn over, opening the circuit between the plates
and d and closing the lighting circuit between plates-e and f and cutting out the
heating or preliminary circuit" H. The attraction of the armature A to the
magnet M is thus dependent upon the second circuit set up by the increased con-
**

page_text: ductivity of the filament F through the leads m ns and the resistance R, which
performs the dual function herein before described with reference to Figure 1.
In cases where two or more filaments or equivalents are used in one lampfor
illuminator, according to my invention these filaments F F F F are placed in
parallel circuit, according to the diagram Figure 3, Sheet 2. A series resistance
may be used as a choking coil or otherwise, or may be dispensed with entirely in
connection with the main circuit. When such a number of filaments or the like
are so arranged they may be enclosed by a single cage, reticulated hood or the
like, I of suitable metal or alloy of high electrical resistance, so that when the
preliminary heating" current through e f passes, sufficient heat is generated in H
to cause the filaments to become incandescent and thus establish a second circuit.
The switch S may then be opened, so that the current is confined to the
filaments F F F F through leads h.
In practice the preliminary current" generally heats up a filament to con-
ducting point by selection, viz.; that of highest conductivity at a given
temperature. The switches S and S may be controlled by a magnetic device as
herein before described, the essential point being in the enclosure of such filaments
within a reticulated hood or cage, as shown diagrammatically by H. The other
filaments or equivalents will remain neutral being practically of negligible con-
ductivity unless heated to the necessary degree of temperature.
This arrangement being sometimes not applicable to ordinary conditions of
working, it may be necessary to place the two electro magnets or solenoids in such
a manner that a step by step or like mechanical device may be operated by them.
I have shown this by Figure 4, Sheet 3, the operation being as follows, that
is to say:
When the switch S is closed, an electrical circuit is established through a
contact springs, contact screw m, contact spring contact screw in through the
coils of the electro magnet (or solenoid) M and return or (-) lead B. The
pivotted armature A is attracted by the magnet or solenoid M and by a projection k
forces forward a lever L, and thus operates a ratchet wheel W by means of a
pawl R, a safety pawl T preventing a return movement or accidental displace-
iment. The oscillation of the armature A and its oscillatory reaction on the pivotted
lever L is due to the "make and break" contact between the screw m³ and the
spring st
When one of the filaments F F F" becomes conductive by reason of
being externally heated as hereinbefore described; another circuit is established
when by the advance of the ratchet wheel W one of the circular switch
arms CCCC comes into contact with either of the contact studs a b c, said
circuit passing through the coils of tlic electromagnet (or solenoid) M¹ and the
neutralizing coils of M (shown by thick lines) through the journal arm Y switch
arm C contact stud filament F to the return lead B(-). Now the electro
magnet (or solenoid) M is neutralized and the opposite magnet (or solenoid) is
energized, consequently the armature A swings over towards M lifting the contact
springs off the contact screw m, thus opening the heating circuit through II, and
the main coils of the electro magnet (or solenoid) M. The contacts are thus
maintained by the lighting circuit energizing the magnet (or solenoid) M and
keeping the armature A in the required position.
I may dispense with magnets or solenoids and use three wires, viz., main
leads B B Figure 5 Sheet 4 und "preliminary circuit" wire a. A time switch S
is interposed in the circuit so as to establish the preliminary heating current through|
H rendering F conductive as herein before described. The time switch is so
arranged as to open the preliminary circuit through a when the current through
the filament F is properly established, as shown by the dotted outline of the switch
arm. The mechanism of the time switch S may be according to any known
type and the general disposition of the installation in this case is that when the
main switch controlling the whole circuit is opened the time switch is restored
automatically to its normal position.
The essential feature of my said invention is in the control of the preliminary

page_text: heating current and the primary or lighting current by an automatic arrange.
ment, whether one or more filaments be used separately or included in one lamp,
and economising energy by such arrangement.
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is:-
First. In electric incandescence lamps in which the filament or equivalent
becomes an efficient conductor only when heated by a separate source or circuit the
construction and use of two magnets or solenoids M M Figure 1 pivotted arma-
ture A contact bars c d e f g h and neutralizing coil and circuits in combination
with a preliminary heating circuit I and filament or equivalent in combination
with a resistance R and switch S for the purpose of automatically breaking the
normally established preliminary heating circuit when the filament F has become
sufficiently heated to maintain a separate circuit, substantially as herein described
with especial reference to Figure 1 Sheet 1 of the appended drawings.
Second. In electric incandescence lamps in which the filament or equivalent
becomes an efficient conductor only when heated by a separate source or circuit
the construction and use of one electro magnet or solenoid M, pivotted arma-
ture A in combination with a preliminary heating circuit I r o and filament or
equivalent F with resistance or shunt K and switch S substantially as herein
described with especial reference to Figure 2 Sheet 1 of the appended drawings.
Third. In electric incandescence lamps in which the filament or equivalent
becomes an efficient conductor only when heated by a separate source or circuit
the method of and means for enclosing several filaments within a cage, hood or
reticulated cover forming part of the "preliminary heating" circuit so as to render
any one or more filaments conductive and incandescent by selection, substantially
as herein described with especial reference to Figure 3 Sheet 2 of the appended
drawings.
Fourth. In electric incandescence lamps in which the filament or equivalent
becomes an efficient conductor only when heated by a separate source or circuit,
the method of and means for automatically controlling the preliminary or heating
circuit by a step by step movement, comprising two electro magnets or
solenoids M M pivotted armature A, lever L, neutralizing coil on M, spring
contacts ss mm ratchet wheel W. pawls R and T and contact arms and
studs C C C C a b c respectively in combination with one or more fila-
ments F F F and preliminary or heating circuit I substantially as herein
described with especial reference to Figure 4 of the appended drawings.
Fifth. In electric incandescence lamps in which the filament or equivalent
becomes an efficient conductor only when heated by a separate source or circuit the
method of, and means for controlling the preliminary or heating circuit by means
of a time switch S of any ordinary type substantially as herein described and
shown by Figure 5 Sheet 4 of the appended drawings.
Dated this 21st dor of A Dril 1890
FREDK. WALKER,
73, St. Stephen's Road, Upton Park, London, E.,
Agent for the Applicant.