Note: Descriptions are shown in the official language in which they were submitted.
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PORTABLE ENERGY CONSUMING DEVICE
This application claims the benefit of Provisional Application Serial No.
60/600,208, filed August 10, 2004.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates in general to portable energy consuming
devices and, in its broadest sense, the novel invention utilizes an external
power
source to store kinetic energy in a portable energy device and simultaneously
store electrical energy in an internal power source in the device only during
the
storing of the kinetic energy such that when the external power source is
separated from the device, the internal power source is used to maintain the
stored
kinetic energy. In particular, the novel invention relates to improved
portable
energy consuming devices such as hair management devices and flat clothes iron
devices that are brought to a desired operating level, such as temperature,
with an
external power source and then the external power source is disconnected and
an
internal power supply, e.g. batteries, maintains only the desired operating
level
thereby extending the life of the internal power supply as well as the life of
the
energy consuming device, e.g. heating elements.
2. Description of Related Art
There are many portable energy consuming devices. There are hair
management devices such as hair curlers or blow dryers that use batteries to
supply the necessary heat.
These devices cause a large current drain on the batteries and shorten the
useful span of the batteries. In commonly assigned U.S. Patent No.'s 6,449,870
and 6,718,651, circuits are disclosed for manually controlling a desired set
temperature of the energy consuming device. In commonly assigned co-pending
provisional patent applications S.N. 60/545,783; and S.N. 60/573,716; and in
commonly assigned U.S. Patent No. 6,732,447, circuits are disclosed for
automatically providing input power, P;,,, in an amount equal to the power
losses,
Pi, (e.g. cooling and system losses) of the portable device so that the power
output, Po, is equal to the residual power, PT, (e.g. kinetic energy such as
heat,
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mass rotation, and the like). Thus, at a desired operating level, such as a
desired
temperature, the input power supplied is simply equal to the power losses and
the
residual power is equal to the output power of the device.
While these devices function well, there is an immense current drain on
the batteries to get the portable device to obtain a desired operating level.
For
instance, wliere a mass is required to be heated to a particular temperature,
it takes
a great deal of battery current to heat the mass (such as the metal mass of a
hair
curling iron) to the desired temperature. By controlling the current drain on
the
batteries as disclosed in the co-pending provisional patent applications, the
remaining life of the batteries can indeed be extended.
However, it would desirable to use an external power source to cause the
mass to reach the desired temperature and then disconn.ect the external power
source and enable the internal power supply, i.e. the batteries, to only
maintain
the desired temperature of the novel portable energy consuming device. In this
novel system, the battery life is extended much further because very little
current
drain from the batteries is used UNTIL the desired operating level is already
reached and the device is then used as a portable device with the internal
power
source simply maintaining that desired operating level (e.g. temperature).
Should
the internal power supply fail for any reason, the energy consuming device can
be
directly connected to the external power supply and used in a conventional
manner.
SUMMARY OF THE INVENTION
With the present invention, the energy consuming device (e.g. hair curling
iron, soldering guns, hot glue guns, flat clothes irons, mass rotors, and the
like) is
brought to a desired operating level (e.g. temperature, rotational speed, and
the
like) by a power source external to the energy consuming device such as an
alternating current (ac) source or an external direct current (dc) source.
Once the
device reaches the desired operating level, the external power source is
disconnected from the device and an internal power source automatically begins
to supply power to the energy consuming device in an amount only sufficient to
maintain the desired operating level. In other words, it supplies just enough
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energy to compensate for power and system losses in the device thereby
enabling
the residual energy (e.g. temperature, mass rotation, and the like) to be
maintained
equal to the desired output power.
The external power source may be ac, dc, RF energy, magnetically
coupled energy, and the like. Hereafter, for simplicity, the external power
source
will be identified as simply ac or dc. The energy consuming device, when a
temperature controlled device, may have either a single heating element for
accepting an external dc power source output for preheating as well as the
internal
power source (batteries) output to maintain the desired operating level or an
ac
heating element for connection to an ac external power source to obtain the
desired operating level and a dc heating element for connection to the
internal
power source to maintain the desired operating level.
When both an ac heating element and a dc heating element is used, the
resistive heating elements may be of several types such as ribbon type
resistances
arranged in different relationships such as electrically insulated coils wound
together in adjacent interposed relationship with each other or in
superimposed,
electrically insulated, fashion. The resistive elements may also be of any
known
type such as wire wound, ceramic, and the like.
A switch may be arranged internally of the energy consuming device that
disconnects the internal power source from the load (e.g. resistive heating
element) when, and only when, the external power source is connected to the
energy consuming device. Thus, when a connector (plug) coimects the energy
consuming device to the external power source, the connector engages and opens
a switch so that the internal power source cannot supply current to the load.
However, when the device reaches the desired operating level and the
external power source is disconnected from the device by removing the
connector
from engagement with the device, the switch in the device is closed thereby
enabling the internal power source to maintain the desired operating level
with the
use of signals that control an electronic switch (such as a power FET) that
couples
the internal power source to the load.
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When the energy consuming device is a flat clothes iron, it is mounted on
a base that has connectors that engage corresponding mating connectors on the
flat clothes iron.
Again, either a single de heating element or both a dc heating element and
an ac heating element may be used as the heating element in the flat iron. In
either case, the proper power source is coupled to the corresponding
connectors
on the flat iron to first bring it to the desired operating temperature and
then the.
flat iron is removed from the base and becomes a portable flat iron. The
internal
power source then maintains the desired operating temperature using the
control
signals.
If desired, the flat iron may have no heating element for an external power
source but would have the internal power source that can be coupled to an
internal
heating element.
In such case, the flat iron is mounted on a base unit having a flat heating
surface that is powered by an external power source. The heat is transferred
by
conduction, metal to metal, to the flat iron until the flat iron reaches the
proper
desired operating temperature. Connectors on the base unit again engage
corresponding connectors on the flat iron to prevent the internal power supply
from supplying power to the heating element until the flat iron is removed
from
the base unit. The removed connectors then allow an internal switcll to close
and
comiect the internal power supply to the internal heating element to only
maintain
the desired heat.
In such case, it is clear that the internal power supply may consist of the
batteries without the novel pulsing circuit disclosed herein. Thus, the unit
is
heated to the desired temperature with the external power source and then,
when
the unit is removed from the external power source, the internal power supply,
the
batteries alone, may be connected to the heating element to maintain the
desired
heat as long as the batteries last. The internal batteries will not last as
long as
when the novel pulsing circuit is used to pulse battery power to the load but
they
will last longer than a portable unit that uses the batteries alone to not
only bring
the unit to the desired temperature but also to maintain the desired
temperature.
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It is to be understood that with an internal power source, the power source
must be insulated from the heat generated in the device. This can be
accomplished in a number of ways. With a hair curling iron, the power supply
(e.g. batteries) can be placed in the handle thereof which is on the opposite
end of
the curling iron from the heating element. The power source may consist of a
plurality of series connected battery cells, a stick type battery, or otller
type power
source (hereafter "power source") that can simply be inserted in or removed
from
the handle as necessary.
With a flat clothes iron, the batteries can again be placed in the handle of
the flat iron which is already heat insulated from the ironing surface to
enable a
user to hold the iron by the handle. Again, the batteries may consist of a
plurality
of series connected battery cells or a stick type power source assembly that
can
simply be inserted in or removed from the handle as necessary. The internal
power source, as stated earlier, may be charged when the energy consuming
device is placed on a base unit.
Thus, it is an object of the present invention to provide a portable energy
consuming device that uses an external power source to enable a desired
operating
level to be achieved and an internal power source to only maintain the desired
operating level once the device is disconnected from the external power source
to
make it portable.
It is another object of the present invention to provide a single dc load in
the portable energy consuming device for both bringing the device to the
desired
operating level with an external dc power source and to maintain the desired
operating level with the internal dc power source when the device is
disconnected
from the external power source and becomes portable.
It is also another object of the present invention to provide a first ac load
for bringing the energy consuming device to a desired operating level with an
external power source and a second dc load for maintaining the desired
operating
level with an internal power source when the device is disconnected from the
external power source and the device becomes portable.
It is still another object of the present invention to provide a base unit on
which the energy consuming device may be placed; the base unit having an
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external power source to enable the energy consuming device to be brought to a
desired operating level and, optionally, for charging the internal power
source in
the energy consuming device only during the time that the external power
source
is supplying power to the energy consuming device.
It is yet another object of the present invention to couple a control circuit
between the internal power source and the energy consuming load to
automatically maintain the desired operating level thereby conserving the
internally located power source as well as prolonging the life of the energy
consuming load.
Thus the present invention relates to a method of creating a portable
energy consuming device comprising the steps of forming a body portion with an
energy consuming load associated therewith; causing the energy consuming load
to achieve a desired operating level using a power source located externally
of the
body portion; removing externally supplied energy from the energy consuming
load when the desired operating level is reached; and only maintaining the
desired
operating level of the energy consuming load using a power source located
internally of the body portion thereby creating a portable energy consuming
device.
BRIEF DESCRIPTION OF THE DRAWINGS
These and other objects of the present invention will be more fully
disclosed when taken in conjunction with the following DETAILED
DESCRIPTION OF THE DR.AWINGS in which like numerals represent like
elements and in which:
FIG.1 is a block diagram illustrating the use of an external power source
only to bring an energy consuming device (device) to a desired operating level
and then using an internal power source to just maintain the desired operating
level and further illustrating the option of using the external power source
to
charge the internal power source (batteries) during the time that the device
is
connected to the external power source;
FIG. 2 is a block diagram illustrating the external power source connected
to a device for bringing the device to a desired operating level while
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simultaneously charging the internal batteries of the device and, further,
illustrating the mechanical corinector that disconnects the internal power
source
(batteries, in this instance) from the load while the device is coupled to the
external power source;
FIG. 3 is a block diagram illustrating the energy consuming device in its
portable state with a control circuit operating an electronic power switch to
provide pulse time modulated power to the load to only maintain the desired
operating level of the device.
FIG. 4 is a block diagram illustrating a base unit on which a flat clothes
iron is placed and illustrating the electrical connections from the external
power
source to connectors on the base unit for engaging corresponding connectors on
the flat clothes iron to both bring the flat clothes iron to a desired
temperature
(operating level) while simultaneously charging the internal batteries
associated
with the flat clothes iron;
FIG. 5 illustrates a base unit that has an AC/DC converter associated
therewitll for generating a dc power signal to bring an energy consuming
device
to a desired operating level while simultaneously generating a dc signal for
charging the internal batteries in the energy consuming device;
FIG. 6A illustrates an ac resistive heating element and a dc resistive
heating element in the form of two flat resistive metal strips wound in
interposed,
electrically insulated relationship, about a common support;
FIG. 6B illustrates an ac resistive heating element and a dc resistive
heating element in the form of two flat resistive elements placed in
superimposed,
electrically insulated relationship, for placement in an energy consuming
device:
FIG. 7 is a schematic diagram illustrating an energy consuming device
such as a hair curling iron mounted in a base unit and illustrating the
external
electrical connections for both preheating the device while simultaneously
charging the device internal batteries;
FIG. 8 is a schematic diagram of a handle for a flat clothes iron or other
energy consuming device illustrating the internal power source, i.e.
batteries, in
the form of either a plurality of series connected individual cells or a stick-
type
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battery that can be removed from the handle and replaced with another power
source when and if needed;
FIG. 9 is a diagrammatic illustration of a flat clothes iron with the internal
power source (batteries) in the handle that connects to a first heating
element and
a second, separate, heating element for connection to an external power
source;
FIG 10 is a diagrammatic illustration of a flat clothes iron that is heated by
conduction from a plate on the base unit that is heated by the external power
source and illustrating the connectors on the base that engage a switch in the
flat
clothes iron to prevent the internal power source from providing power to just
maintain the desired operating temperature; and
FIG. 11 illustrates a control circuit shown in commonly assigned co-
pending provisional patent application S.N. 60/573,716 that can advantageously
be used with the present invention.
DETAILED DESCRIPTION OF THE DRAWINGS
It is well known that devices that require significant power to enable them
to reach a desired operating level or condition are difficult to make into
portable
devices because of the size of the batteries or internal power source that are
(is)
required to just get the device to the desired operating level. By the time
the
desired operating level is reached, the internal power source (e.g. batteries)
is
(are) so depleted of energy that there is little internal power source energy
remaining to use to just maintain the desired operating level.
If the device could be brought to the desired operating level or condition
with the use of an external power source and then the device was made portable
by disconnecting the external power supply, an internal power supply could
then
be used to just maintain the desired operating level. The device would then be
truly portable and could be used without the physical interference of an ac
cord.
The present invention meets these requirements by using an external
power source to store kinetic energy (such as temperature or a rotating mass)
in a
selected energy consuming device until a desired operating level is reached
and
then the external power source is disconnected from the device to make the
device
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portable. An internal power source is then automatically used to just maintain
the
kinetic energy at the desired operating level.
Such a device is disclosed in FIG. 1 wllerein is shown a block diagram 10
illustrating a generic embodiment of the present invention. As can be seen, an
energy consuming device 12 (hereinafter called "device") has an external power
source 14 removably coupled to the device 12 by means of conductors 16 to a
load element 18 located within the device to cause the device 12 to reach a
desired operating level. Then, when the desired operating level is reached,
the
external power source 14 is disconnected from the device 12, device 12 becomes
portable, and an internal power supply 20 is coupled to its own load eleinent
22 to
just maintain the desired operating level of the device 12.
The internal power source 20 may, as stated earlier, consist of internal
batteries only and, in such case, the external power source 14 brings the
device to
the proper operating temperature and thein it is disconnected and the internal
batteries, alone, are connected to the device to maintain the temperature of
the
device. The batteries or power source 14 will not last as long as when used
with
the pulsing circuit disclosed herein but will last longer than a device that
uses the
internal batteries to both heat the device to a desired temperature and then
maintain that desired temperature.
Of course, the internal power source 20 may consist of the internal
batteries and a pulsing circuit as will shown hereafter to pulse the power of
the
internal batteries to the load. In such case, the life of the internal
batteries is
extended even longer as will be disclosed hereafter.
Consider, as an example only, a hair curling iron. The iron has a metal
mass serving as the heated surface and it must be raised to a sufficiently
high
temperature to enable it to be used. This is accomplished in the prior art by
the
use of alternating current (ac) and it takes several minutes to bring the
metal mass
to a temperature sufficient for use in curling hair. Then when it is used, the
ac
cord must remain attached to keep the iron hot.
It is highly desirable to make the curling iron portable and eliminate the
physical interference of the ac cord. However, if the curling iron is made
portable, no cord is attached and no ac is used. Thus, the internal power
source
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must be placed under a severe power drain to bring the device to the desired
operating level (in this example, temperature).
Thus, it can be seen with the block diagram of FIG. 1 that if the device 12
is a hair curling iron, it can be heated to the desired operating level or
teinperature
with the external ac power source 14. When the mass of the curling iron
reaches
the desired operating level, or temperature, the ac cord 16 is disconnected
from
the hair curling iron 12 in a well know manner as by means, for example, of
unplugging ac connectors from the device 12. An internal power source, as will
be shown hereafter, is then automatically utilized to just maintain the
desired
operating level or temperature.
In the generalized embodiment shown in FIG. 1, the external ac power
source utilizes and is connected to its own ac heating element located within
the
device 12.
Once the ac cord is disconnected from the device 12, the internal power
source 20 is automatically connected to its own dc heating element 22, as will
be
explained hereafter, to cause the device 12 to maintain its desired
temperature.
Also, as shown in FIG. 1, the external power source 14 may be used to
charge the internal power source 20 by means of a second conductor 24, shown
as
a phantom line, whenever the device 12 is mounted in a base unit as will be
shown hereafter.
Of course, the device 12 illustrated generally in FIG. 1 could, in addition
to a hair curling iron, represent any hair management device, such as a blow
dryer, that requires large amounts of energy to get the device to the proper
temperature. Device 12 in FIG. 1 could also represent a flat clothes iron, a
soldering gun, a glue gun, a rotating mass, and the like.
Further, when a blow dryer represents the hair management device, the
life of the batteries can be further extended by causing the air generated by
the
blower fan to pass over the batteries and cool them. It is well known that as
batteries are used continuously over an extended time period, the internal
resistance of the batteries increases. This increased resistance causes the
batteries
to heat as well as to decrease their external output voltage. If the batteries
are
then cooled, the output voltage returns to a higher level. Thus, this unique
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method of using the blower fan to cool the batteries extends the life of the
batteries during a given RUN cycle as well
as extending the entire life of the battery. Such improvement is a valuable
asset to the use of portable devices.
FIG. 2 is a schematic representation of a device 12 and illustrating a
generalized version of the electronics associated therewith. The internal
power
source 20 in FIG. 2 is coupled, through switch 28, to a dc heating element 22.
When the device 12 is to be brought to a desired operating level, such a
teinperature, an external ac source 14 and connected power cord 16 has on the
end
thereof an elongated connector 26 of any well-known type in the art that is
inserted in a mating receptacle (not shown) in the device 12 in a well-known
maiuler to connect the external power source to an internally located ac load
such
as heating element 18, for example only, on lines 32 and 34.
At the same time, if desired, the ac input can be connected to an ac/dc
converter 30, either internal or external (shown here as internal) that can be
used
to charge the internal batteries 20 in a conventional manner.
When the ac heating element 18 causes the device 12, here a temperature
device, to reach the desired operating level (temperature in this case), the
connector 26 is withdrawn from the mating receptacle to make the device
portable. When that happens, switch 28 returns to its normally closed position
thereby connecting internal power source 20 to its own dc load 22 on line 36.
As
will be shown hereafter in relation to FIG. 3 and FIG. 11, a control circuit
38
provides just sufficient energy from the internal power source 20 to cause the
device 12 to only maintain the desired operating level.
The circuit shown schematically in FIG. 3 includes control circuit 38 that
is powered by the internal power source 20. When connector 26 (here
represented
by a phantom line) is disconnected from the device 12, switch 28 closes as
explained earlier.
An electronic switch 40, such as a power FET, is opened and closed by the
control circuit 38 with the use of Pulse Time Modulated signals to modulate
the
power signal to load 22 from the internal power source 20. A light emitting
diode
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(LED) 42 may be utilized, if desired, to let the user know that the control
circuit
38 is functioning.
The novel invention works well with any load requiring heavy current to
bring it to a desired operating level as explained earlier. FIG. 4 illustrates
a flat
clothes iron 46 mounted on a base unit 44 shown in cross-section. The flat
iron
46 has a handle 47 that is sufficiently temperature insulated from the heated
body
portion of flat iron 46 to enable a user to pick up and use the heated flat
iron 46.
It will be noted in FIG. 4 that an external power source 14 is coupled
through cord 16 to a connector that is plugged into the base unit in a well-
known
mamler as explained previously. In this example, external ac power is
connected
directly to connector 52 by conductor 50 to preheat the iron when a switch on
the
base (not shown here) is operated by a user when the user desires to use the
flat
iron. At the same time, if desired, the internal power source can be charged
by
the output from an ac/dc converter 48 on connector 26. When the iron reaches
the
desired temperature as may be shown in a well-known manner by an LED 76
shown in FIG. 10, the iron may be removed from base unit 44 and thus becomes a
portable iron. It should be noted that while the ac/dc converter 48 is shown
to be
a part of the base unit 44, it can be external to the base unit 44 if desired.
Thus,
the flat iron 46 shown in FIG. 4 utilizes first and second heating elements
located
internally of the flat iron 46. One heating element is an ac heating element
(to be
used by the external power source) and the other is a dc heating element (to
be
used by the internal power source).
The flat iron 46 could, if desired, have only one heating element and that
is a dc heating element that would be used first during the preheating on the
base
unit 44 and then, when the flat iron 46 is disconnected from the base unit 44
to
make the flat iron portable, the single dc heating element would be connected
to
the internal power source 20 to just maintain the desired temperature. As
shown
in FIG. 5, the base unit 44 has an ac/dc converter 48 associated therewith,
either
internal (as shown) or external to the base unit 44. The device, then, uses
the dc
power source for preheating a single dc heating element and when the device is
disconnected from the base unit 44 to make the device portable, the internal
dc
source is coupled to the same single dc heating element. Such a connection
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would be obvious to one skilled in the art given the assignment of creating
such
connection and therefore is neither shown nor explained here.
When two heating elements, an ac and a dc element, are desired to be
used, they may be formed in any desired manner. For example, if the device is
a
hair curling iron, the resistive heating elements may be wound in a circular
fashion about a non-electrically conductive cylinder 17 as shown in FIG. 6A.
The
two resistive elements 18 and 22 are wound about non-electrically conductive
cylinder 17 in an interposed, spaced, non-electrical conducting relationship
as
shown. Of course, one skilled in the art would know how to create other types
of
arrangements such as a side-by-side relationship.
If the heating elements are of the flat resistive types, one may be
superimposed over the other in a non-electrical conducting relationship as
shown
in FIG. 6B where a flat ac heating element 18 has superimposed thereon and
electrically insulated therefrom by insulator 54 a flat dc heating element 22.
One
skilled in the art would know of other fashions in which the two heating
elements
18 and 22 could be advantageously arranged.
FIG. 7 illustrates a base unit 44 on which a hair curling iron 64 (shown in
phantom lines) could be mounted for preheating and charging of its internal
power supply. The internal power supply may be batteries as is well known in
the
art. Again, an ac power source, represented by electrical plug 14, is
connected by
cord 16 to a connector 56 on the base unit 44 as explained earlier. Also as
explained earlier, the hair curling iron 64 could have a single heating
element for
both preheating and portable operation. As shown, however, a first heating
element is used for preheating with the external ac power source and a second
heating element is used for portable operation with the internal dc power
source.
The ac input from the external power source is connected directly to
connector 62 on the base unit 44 while the dc power for simultaneously
charging
the internal power source comes from an ac/dc converter 58 whose dc output is
coupled to connector 60.
The power cord 16 terminates at the base unit 44 with a connector 56.
Advantageously, connector 56 is identical to the connector 62 on base unit 44.
If,
for any reason, the portable operation of the device 64 is prohibited, the ac
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connector 56 can be plugged directly into the device 64 where power is
normally
supplied by connector 62. In such case, the hair curling iron 64 may
advantageously continue to be used as a conventional cord attached, non-
portable
hair curling device.
In any use of batteries with a heating device, the batteries must not be
subject to heating from the heating elements. In a hair curling iron, the
batteries
may be placed in a heat insulated handle as is well-known in the art and which
is
heat insulated from the heating element.
When the novel invention is used with a flat clothes iron, the batteries
must be especially protected from the heat maintained by the large metal mass.
One such way of heat insulating the batteries is shown in FIG. 8. As shown,
the
batteries may be separate battery cells 20 or a well known battery "stick" 66
that
can be inserted in well known fashion into the handle 47. With battery "stick"
66,
the battery is simply slid into and out of the handle to replace it or to
charge it
externally of the flat clothes iron in a well known fashion. In like manner,
the top
of the handle 47 could be a hinged plate (not shown) that could be opened and
closed in a well known manner to remove and insert batteries. One skilled in
the
art would understand other methods of mounting, and insulating, the batteries
to
protect them from the heat.
FIG. 9 is a diagrammatic depiction of a portable flat clothes iron 46
having a handle 47 with batteries 20 (internal power source) located therein.
The
batteries are diagrammatically shown to be connected to a dc load 22 such as a
dc
heating element while an ac load such as an ac heating element 18 is shown
connected to at least one receptacle 50 for receiving power from an external
power source wllile preheating.
FIG. 10 illustrates schematically an alternate embodiment of the invention.
In this embodiment, the flat clothes iron 46 has no internal heating
element for preheating. In this embodiment, the base unit 68 has an upper
plate
70 that is preheated by the external power source represented by wall plug 14
through cord 16. The flat clothes iron 46 simply sits on the heated plate 70
in
metal to metal contact to preheat the flat iron 46. When the flat iron 46 is
preheated, as may be indicated in a well known fashion by LED 76, it is made
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portable by removing it from the base unit upper plate 70. At least one
connector
72 has prevented the internal power source 20 from powering the dc heating
element during preheating. When the flat iron 46 is removed from the base unit
68, the at least one connector 72 is removed from a corresponding receptacle
that
enables the portable, internal power, operation as explained previously with
respect to FIG. 2.
Of course, in all of the embodiments described above, a switch 74
diagrammatically illustrated in FIG. 10 can be used to prevent the device 12
from
preheating while it is placed on the base unit.
FIG. 11 is a schematic diagram of the electronic control circuit for the
novel invention herein that supplies only sufficient Pulse Time Modulated
energy
to the device to replace only load losses a.nd to maintain the desired power
output
and thereby conserve battery energy that would otherwise be wasted. This
diagram has been explained in detail in co-pending commonly assigned
provisional patent application S.N. 60/573,716.
Briefly, however, unit 78 is a detector that senses the desired operating
level (e.g. a temperature sensor 80 as shown in Fig. 11). Oscillator 94
generates,
in this case, a sawtooth wave output on line 96 that is coupled, along with
the
amplified detector 78 signal on line 90 to a comparator 92. As long as the
amplitude of the amplified output of detector 78 on line 90 is greater than
the
amplitude of the oscillator 94 output on line 96, there is a constant output
from
the comparator 92 through resistor 100. This signal is coupled through switch
28
to the gate of power FET 102 causing it to conduct and apply maximum power to
the load 22.
However, as explained earlier, to save the internal batteries, the device
has, in this instance, an ac heating element 18 that is heated to bring the
device to
the desired operating temperature. As can be seen in Fig. 11, the device is
first
heated to the desired operating temperature with an external ac power supply
44.
The external power supply 44 is coupled to the energy consuming device by
means of, in this case, a male connector 26 that makes contact with points 75
and
76 (on line 16) to provide power to the ac load 18 in the device. Switch 74 is
a
double pole, single throw switch that first couples the external ac source to
the ac
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load heating element 18. In addition, the other half of switch 74 couples the
internal power supply (batteries) to the control circuit described above.
Because
the control circuit uses such little power, little drain is placed on the
internal
batteries during the time the external power supply is bringing the device to
the
desired operating temperature. As explained earlier, the male connector,
represented by phantom line 26, physically opens switch 28 thus preventing the
FET from receiving any signal from the control circuit of the device. Thus no
power is being supplied to the dc load 22 during the time that the external ac
power source is heating the device to the desired operating temperature with
the
use of ac heating element 18. When the ac heating element or load 18 causes
the
device to reach the desired temperature (which can be indicated in a well
known
manner by illumination of an LED), the device is removed from its base and the
male connector 26 is removed from the device closing switch 28 and allowing
the
signal from the comparator 92 of the control circuit to be connected to the
power
FET 102 which begins to apply power to the dc load 22. Because dc load 22 is
in
physical proximity to the metal mass that has been heated by the external
power
source 44, the dc load 22 is already heated to the approximate desired
operating
teinperature and the power FET 102 now is Pulse Time Modulated by the control
circuit to provide just enough energy to dc load 22 to maintain the desired
operating temperature of the device.
An LED 103, if desired, may be coupled across FET 102 and pulses with
the pulsing of the FET to indicate to the user that the control circuit is
functioning.
Thus, there has been disclosed a novel improved portable energy
consuming device that uses an external power source to cause the device to
reach
a desired operating level and then when the device is removed from its base,
the
external power source is disconnected from the device and the internal power
supply is then automatically connected to a dc load to maintain the desired
operating level of the device. A control circuit is coupled between the
internal
power source and the dc load to Pulse Time Modulate the signal applied thereto
to replace only load losses and to just maintain the desired operating level.
As
explained earlier, the desired operating level is intended to mean a desired
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operating temperature, a desired operating rpm, or any other type of load
operating condition that has kinetic energy that will maintain the desired
operating condition if sufficient energy is provided to just replace the
device
losses.
While particular embodiments of the invention have been shown and
described in detail, it will be obvious to those skilled in the art that
changes and
modifications of the present invention, in its various embodiments, may be
made
without departing from the spirit and scope of the invention. Other elements,
steps, methods, and techniques that are insubstantially different from those
described herein are also within the scope of the invention. Thus, the scope
of the
invention should not be limited by the particular embodiments described herein
but should be defined by the appended claims and equivalents thereof.
It is to be understood that the term "electronic switch" as used herein is
intended to cover suitable switch that can be controlled to intermittently
supply
power to a load including mechanically operated switches such as a relay or a
solid state switch such as a Field Effect Transistor (FET) as discussed herein
previously.
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