Note: Descriptions are shown in the official language in which they were submitted.
~076~1L96
The present invention relates to a smoker's
lighter with battery ignition and particularly relates
to an electrical switch in the ignition circuit for operating
the lighter.
In the known type of a cigarette lighter with
battery ignition, there is a manuall~ operable mechanical
switch for controlling the ignition circuit which causes
spark generation to ignite a gaseous fuel. The switch
is constituted by precision parts, the manufacturing of
which is really expensive and in which more or less severe
wear cannot be avoided in long run because the switch
is actuated through mechanical operation accompanied with
percussion and friction of the parts.
The ignition circuit in general comprises a
- charging circuit for charging a capacitor and a discharging
circuit for discharging the capacitor, in which the switch
is provided between charging and discharging circuits
or in discharging circuit and connects the capacitor to
the discharging circuit for ignition. In this case, as
a surge current from the capacitor flows to the discharging
circuit through the switch, the contacts of the switch
- sustain contact-breaking sparks which often cause ~urther
wear thereof.
Further the switch button is conventionally
exposed externally of the lighter casing and so constructed
that the switch button may simultaneously actuate the
switch and a gas outlet valve. Therefore there is a danger
of inadvertent or unexpected operation of the lighter,
for example when in a user's pocket. Recently there is
an increasing demand to design a lighter so as to prevent
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such accident and there are known several ways to do so,
for example, to increase the force required to operate
the switch. However it will be apparent that such increase
in the operating force causes inconvenience in actual use
and reduces the value of the lighter.
The present invention is directed towards providing
an improved gas-fuelled electric lighter which overcomes
the above-mentioned disadvantayes.
According to the present invention there is
` 10 provided a gas-fuelled electric lighter comprising a casing,
a fuel tank for holding fuel gas arranged within the casing,
a burner valve in communication with the fuel tank, a burner
nozzle in communication with the burner valve, a spark gap
arranged adjacent to the nozzle, an ignition circuit adapted
to generate sparks at the spark gap, a battery for energizing
the ignition circuit, a switching means electrically connected
to the ignition circuit in order to control the operation
of the ignition circuit and including two fixed switch contacts
being electrically insulated from each other, and a mechanical
switch being electrically connected to at least one of the fixed
switch contacts of the switching means to define operable and
inoperable states of the switching means, wherein the switching
means is adapted to function only when an electrically conductive
substance is placed on the fixed switch contacts in the closed
state of the mechanical switch.
The lighter may comprise an insulation holder
secured to the casing, with the two fixed switch contacts
arranged on the insulation holder so as to be electrically
insulated from each other and from the casing.
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Preferably, the casing of the lighter may have
an open end with a cap pivotally mounted thereon, and the
mechanical switch may be adapted to be actuated by movement
of the cap. The burner valve may also be movable in accordance
with pivotal movement of the cap. At least one of the fixed
switch contacts may be located at a position inaccessible
when the cap is in the closed position.
The ignition circuit may comprise a charging circuit
comprising a DC-DC converter which increases the level of voltage
from the battery to a higher level for charging a capacitor,
and a discharging circuit comprising a step-up transformer
and a switching element, the primary winding of the transformer
being in series connected to the capacitor and the secondary
winding being connected to the spark gap, the switching
element adapted to discharge the capacitor at the predetermined
voltage level.
The switching means and mechanical switch may be
electrically connected in series with each other between the
battery and the ignition circuit.
The switching means controlling the operation of
the ignition circuit may comprise a semiconductor switching
deviee having high input impedance and low output impedanee,
the fixed switeh eontaets being eonneeted to input terminals
of the semieonductor switching device to operate the device
by eonduetion between the fixed switeh eontaets, and output
terminals of the semieonductor switehing deviee being eonneeted
to the ignition circuit. The semiconductor switching device
may eomprise a field effeet transistor.
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Thereneed not be used any mechanical component
part movable to effect electrical switching. According
to a preferred feature of the present invention, the switching
means includes a semiconductor switching device having
high input impedance and low output impedance, which con-
stitutes a feed back amplifier. The fixed switch contacts -~.
are located onthelighter case and are electrically connected
to input of the semiconductor switching device to operate
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said device by conduction between the contacts through ~ .
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user's finger. The output terminals of the semiconductor
switching device are connected to the one section of the
ignition circuit and are adapted to operate the ignition
circuit which generates sparks at the spark gap upon operation
of the switching means.
The switching contacts can be mounted on the
surface of the lighter case and the switch does not take
the internal space of the lighter~ Further the semlconductor
switching device may be constructed as an integrated circuit
together with the ignition circuit thereby making the
bulk of such circuit small.
A feature of the switching means is that since
the switch contacts do not move upon actuation thereof,
there is not severe wear thereof due to contact-breaking
sparks or mechanical percussion and friction.
For the purpose of preventing inadvertent operation
1 of the ignition circuit, there is further arranged an
r~ auxiliary mechanical switch in the ignition circuit.
Preferably, the auxiliary switch is actuated in accordance
with the movement of a lighter cap. It will be understood
that, when at least one of the switching contacts is located
at a position inaccessible when the cap is closed, the
auxiliary switch may be deleted since the switching means
cannot be actuated while the cap is in its closed state.
By way of example only, the invention will now
be described with reference to the accompanying drawings, ~ `
in which:-
FIGURE 1 is a circuit diagram of a first embodiment
of the ignition circuit used in a lighter according to
the present invention.
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1~76~l96
FIGURE 2 iS a circuit diagram of a second embodiment
of the ignition circuit used in the lighter according
~ to the present invention.
: FIGURE 3 is a part-sectional elevation of the
lighter according to the present invention. -
FIGURE 4 is a ~ragmentary, part-sectional elevation
of the lighter of Figure 3 depicted with the cap of the
lighter in its open position.
Referring now to Figure 1, there is shown the
10 first embodiment of the spark discharge ignition cixcuit,
in which a battery 1 is connected to an auxiliary mechanical
; switch 2 (described later) and is further connected to
electrical switch means 3 in series. The electrical switch
means 3 comprises two fixed switch contacts 4 adapted
to be touchable with user's finger from the outside of
the lighter and one of which is connected to a terminal 5,
two transistors Trl, Tr2 in which the transistor Trl is
connected at its base side to another switch contact 4
and in whlch the transistor Tr2 is connected at its collector
side to a terminal 6 and at its emitter side to the battery 1,
and two resistors R1, R2 and a capacitor Cl which are
connected to the base of the transistor Trl for stable
operation of the transistors Trl, Tr2.
; The collector of the transistor Trl is connected
to the same of the transistor Tr2 and the emitter o~ the
transistor Trl is connected to the base oE the transistor
Tr2. This connection is known as Darlington connection
which constitutes a ~eedback ampli~ier having a high input
impedance and a low output impedance.
The electrical switch means 3 is the so-called
touch switch which is actuated by putting user's finger
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76~96
on the fixed switch contacts 4. This allows a minute
current to flow from the battery 1 to the base of the
transistor Trl against the skin resistance of user's finger
and the transistor Tr2 is saturated to connect directly
the battery to a DC-DC converter I which is connected
to the electrical switch means 3 at terminals 5, 6.
The DC-DC converter I consists of a transistor
Tr3, a resistor R3, an oscillation transformer Tl and
a half-wave rectifier Dl. The base of the transistor
Tr3 is connected to the terminal 5 through the resistor
R3 and a feedback winding of the oscillation transformer
Tl. The emitter of the transistor Tr3 is connected to
the terminal 6. The collector of the transistor Tr3 is
connected to the terminal 5 through a primary winding
of the oscillation transformer Tl. The half-wave rectifier
Dl is connected at its positive side to a secondary winding
of the oscillation transformer and at its negative side
to the positive terminal of a storage capacitor C thereby
to charge the capacitor C. .
A SCR (silicon controlled rectifier) D3 is con-
nected at its anode side to the positive terminal of the `
storage capacitor C and at its cathode side to a primary
winding of a step-up transformer T2 for discharging the ;capacitor C~ A zener diode D2 and a resistor R~ are connected
to a gate of the 5CR D3 to trigger the same at a predetermined
level of the charged voltage on the storage capacitor C.
A secondary winding of the step-up transformer T2 has
a pair of discharge electrodes 7, 8 to discharge sparks
to ignite a fuel gas. ~ : :
. 30 The auxiliary mechanical switch 2 shall preferably
be arranged to prevent inadvertent or unexpected operation
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of the ignition circuit. For this purpose, the lighter
which will be explained hereinafter as one of the preferred
embodiments has a cap mounted on the lighter case to actuate
the auxiliary mechanical switch. The same effect may
be achieved without using such an auxiliary switch by
locating at least one of the switch contacts at a position
inaccessible when the cap is closed, for example at a
portion of the casing covered by the cap when it is closed,
so that operation of the electrical switch due to some
10 material inadvertently bridged over the fixed con~acts
may be prevented. If one of the fixed contacts is formed
by the lighter casing, the other fixed contact may be
located at such a position.
;In operation of the ignition circuit, when the
-auxiliary mechanical switch 2 is closed and then further
user's finger touches the two fixed switch contacts 4,
the battery is directly connected to the DC-DC converter I.
The DC-DC converter I increases the level of the voltage
from the battery to a higher level for charging the storage
capacitor C. When the charged voltage of the storage
capacitor C reaches a predetermined level, which depends
on the trigger elements, the zener diode breaks down to
trigger the SCR D3. Firing of the SCR D3 permits the
built-up charge on the capacitor C to discharge suddenly
through the primary winding of the step-up transformer T2
and anode-cathode path. This induces a very high voltage
of short duration in the secondary winding. A spark discharge
is therefore produced between the discharge electrodes 7,
8. The sparking continues automatically and periodically
until user's finger leaves the two fixed switch contacts 4.
~076196
Referring to Figure 2, there is shown the second
embodiment of the ignition circuit used in the lighter
according to the present invention. The ignition circuit
comprises a battery 1, an auxiliary mechanical switch 2
connected between the battery 1 and a storage capacitor C
; for charging the capacitor C, a step-up transformer T,
a protective resistor R2 for the battery 1, and an electrical
switch means 30 connected to the positive side of the
capacitor C for discharging the capacitor C through a
primary winding of the step-up transformer T. A secondary
: winding of the step-up transformer T is connected to discharge
electrodes 7, 8. The protective resistor R2 functions
as protection for the battery 1 as the battery 1 is short~
circuited upon actuation of the electrical switch means 30.
. The electrical switch means 30 consists of a transistor Tr
whose collector is connected to the positive side of the
capacitor C and whose emitter is connected to the primary : ~ -
winding of the step-up transformer T, and a pair of fixed
switch contacts 4 one of which is connected to the base ..
of the transistor Tr and the other of which is connected
to the collector through a base bias resistor Rl.
In operation of this ignition circuit, the storage
capacitor C is charged by the battery 1 in response to
the operation of the auxiliary mechanical switch 2. When
user's finger touches the switch contacts 4, a minute :~
current flows from the battery 1 to the base of the trans-
istor Tr through the base bias resistor Rl and the user's
finger. Then the transistor Tr is saturated to discharge
the capacitor C through its collector-emitter path and
the primary winding of the step-up transformer T so that
spark discharge is produced between the discharge electrodes
7, 8.
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The electrical switch means 30 may be substituted
by such electrical switch means as shown in Figure 1.
Since the discharge circuit loop is constituted by the
capacitor C, the collector-emitter path and the primary
winding, and mechanical switch contacts are not used in
this loop, there are not any contact-breaking sparks due
to the surge current of the capacitor.
The auxiliary mechanical switch 2 is used to
prevent the leak current of the storage capacitor C as
well as to prevent inadvertent or unexpected operation
of the ignition circuit.
Figures 3 and 4 illustrate the lighter according
; to the present invention which employs the ignition circuit
as shown in Figure 1 or 2. The lighter comprises the
ignition circuit unit 101, a casing 102 and a lighter
cap 103, a fuel tank 104 having a burner valve (not shown)
on which a burner nozzle 105 is mounted, a windshield 106
- covering the burner nozzle 105, having a flame opening 106a,
and a telescopic spring-loaded cylinder 107 for controlling
the movement of the lighter cap 103. One end of the cylinder
107 engages a leg 108 which is secured to the inside of
the ca~ 103. The other side o~ the same engages an insulation
frame 109 which secures a discharge electrode 7 and a
switch contact piece 2a. The discharge electrode 7 cor-
responds to the discharge electrode 7 of the ignition
circuit shown in Figure 1 or 2. The tip 8 of the burner
nozzle 105 corresponds to the discharge electrode 8.
The switch contact piece 2a is used as a switch lever
of the auxiliary mechanical switch 2 as shown in Figure 1
- 30 or 2. In opened position of the cap 103, the switch contact
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piece 2a engages the leg 108 to contact with the windshield
106 which is also used as a switch contact of the auxiliary
mechanical switch 2. A hinge 110 pivots the lighter cap 103
to the casing 102 and the lighter cap is movable. A valve
actuator 111 with a protrusion llla controls the open and
close movements of the burner valve. One end of the valve
actuator 111 is adapted to catch a neck portion oE the
burner nozzle 105 and the other is slidably mounted on
a screw 112. Inserted into the ignition circuit unit 101
is the screw 112 around which a valve actuating spring 113
is arranged. The valve actuating spring 113 biases the
valve actuator 111 upwardly to open the burner valve (not
shown). In closed position of the cap 103, the side face
of the cylinder 107 engages the head of the protrusion llla
to urge downwardly the valve actuator 111 thereby to close
- the burner valve. Two fixed switch contacts 4 are electri-
cally insulated from each other and from the casing 102
by an insulation contact holder 4a which is secured to
the casing 102. The two fixed switch contacts 4 correspond
to the switch contacts 4 as shown in Figure 1 or 2.
The method of operation of the lighter will
now be explained. When the lighter cap 103 is opened,
assisted by spring force by the telescopic cylinder 107,
the cylinder 107 pivots in a clockwise direction around
the insulation frame 109 away from the protrusion llla.
The valve actuator 111 is raised by the spring 113 so
that the burner nozzle 105 is raised to open the burner
valve allowing fuel gas to issue from the tip 8 of the
burner nozzle 105. At the same time the leg 108 urges
the switch contact piece 2a towards the windshield 106 ~ `
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and thus the auxiliary mechanical switch is closed. Then
putting the finger on the fixed switch contacts 4 closes
the electrical switch in the same way as explained in
connection with Figure 1 or 2.
Although the invention has been described in
its preferred form, various changes in the shape and arrange-
ment of parts may be made. Some of the examples of these
changes will be explained hereinafter~ ~ -
A field effect transistor (FET) has also the
required high input impedance and low output impedance.
- Therefore a FET may be used in the electrical switch means
in the ignition circuit of Figure 1.
When the terminal 5 of the DC-DC converter I
is electrically connected to the casing 102 and the windshield
; 106, only one of the fixed switch contacts 4, the one
connected to the base of the transistor Trl, may be electri-
cally insulated from the casing 102. In this case, the
` casing 102 shall be appropiated to the other switch contact
- of the electrical switch means 3.
Further in Figure 1, the electrical switch means 3
may be used as a trigger switch of the SCR in place of
the zener diode D2, instead of placing the electrical
switch means 3 between the battery 1 and the DC-DC converter I. ;
Both ignition circuits as shown in Figures 1
and 2 are a capacitor discharge spark ignition type; however,
various other kinds of battery spark ignition circuit
may be used in the lighter according to the present invention,
with the above-mentioned so-called touch switch being
applied in such ignition circuits.
Further in Figure 3, the surfaces of the two
fixed switch contacts 4 and insulation holder 4a are flush
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with the surface of the casing 102. In this case, when
~:: the lighter design does not include the cap 103 and the ~ .
auxiliary mechanical switch 2, the switch contacts 4 may i
accidentally be electrically connected to operate the -~ :
: lighter by other metallic articles in user's pocket.
However this danger may be easily reduced by forming the
- contact surfaces slightly recessed from the surfaces of
insulation holder 4a and the casing 102, or the insulation
holder portion between the contacts 4 may be formed slightly :~
projecteù from the contact surfaces. ;
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