Note: Descriptions are shown in the official language in which they were submitted.
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Thermal Body-Care Element and Method of Use of Same
Background of the invention
The present invention relates to a system for applying heat to the skin of
a body, such as a human body. The heat application surface is small,
lightweight, and cordless.
Heated, skin care devices are known. Some of these provide motion,
such as heated massagers, while others simply apply heat for therapeutic,
cosmetic, and/or other purposes.
Burkardt, US Pat. No. 2,985,166, purports to disclose a heated
massaging device including both a motor to provide vibrating motion to the
skin
and a heating coil to provide heat to the skin. However, in order to provide
the
power for both motion and heat, the device is directly connected to an
external
power source, such as a household electrical receptacle. The device is not
cordless.
Rhoades, US Pub. Pat. App. No. 2003/0165550 Al, purports to disclose
a battery-operated vibrating microdermabrasion device that may include a
heating unit disposed within or adjacent to the device. While the embodiments
described in detail in Rhoades are cordless, there is no detail how the
heating
unit would be included, and it is not clear that such a unit could be cordless
in
operation.
Gebhard, US Pat. No. 6,001,070, purports to disclose a cordless facial
iron that incorporates rechargeable batteries. The facial iron has a spoon
shaped heating surface for applying heat to a user's skin. The heating surface
is powered by the rechargeable batteries and is activated by a
thermostatically
controlled circuit. This cordless device lacks a motor to provide motion to
the
heating surface that contacts the user's skin.
Finally, Li et al., US Pat. No. 6,245,093, purports to disclose several
embodiments of an apparatus to treat skin itch and skin rash. The apparatus
includes a body heater that can apply heat with a cycle time and pulse. In one
embodiment, a motor and crank system moves the heating unit into and away
from skin contact to provide this cyclic heating. However, such a movement of
the heating unit does not provide substantial movement of the skin that is
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provided in motions such as vibration, reciprocation, oscillation, rotation,
and
the like.
Despite the teaching of the prior art, there is a continuing need for skin
care devices that provide sufficient heat for a long enough time to deliver
the
benefits of a heated surface with the portability of a manual or battery-
powered
device.
Summary of the invention
We have discovered that it is possible to provide the desired portability
by de-coupling the power to heat the device from the power (if any) to provide
motion to the skin-contacting surface of the device.
In one embodiment, a thermal body-care element includes a container
having at least one thermally conductive surface enclosing an electric heater
in
thermal contact with a thermal energy storage medium comprising a phase
change storage medium and an electrical connection for selective coupling to
an external electrical power source. The external electrical power source is
external to the thermal body-care element.
In another aspect of the invention, a method of applying heat to a skin
surface of a human or animal includes a) electrically connecting an electric
heater to an external electrical power source to heat a thermal energy storage
medium in thermal contact therewith; b) disconnecting the electric heater from
the external electrical power source; and c) applying the body-care surface to
the skin surface while the electric heater is disconnected from the external
electrical power source. The electric heater and thermal energy storage
medium are in a container arranged and configured for gripping by a human
hand.
Brief Description of the Drawing
Fig. 1 is a side elevation of a skin care device according to the present
invention.
Fig. 2 is an end view of the skin care device of Fig. 1.
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Fig. 3 is a cross-section of the housing of the skin care device of Figs. 1
and 2 and its contents, with the thermal body care element removed, taken
along section line 3-3 of Fig. 2.
Fig. 4 is a perspective view of a thermal body care element, useful in the
device of Figs. 1-3.
Figs. 5A-E are various views of the thermal body care element of Fig. 4.
Fig. 5A is a bottom plan view of the heat-generating element.
Fig. 5B is a side elevation of the heat-generating element.
Fig. 50 is a cross-section of the heat-generating element taken
along section line 50-50 of Fig. 5A.
Fig. 5D is a cross-section of the heat-generating element taken
along section line 5D-5D of Fig. 5A.
Fig. 5E is a cross-section of the heat-generating element taken
along section line 5E-5E of Fig. 5B.
Fig. 6A is side elevation of an alternative thermal body-care element
according to the present invention.
Fig. 6B is bottom plan view of the alternative thermal body-care element
of Fig. 6A.
Fig. 7A is a perspective view of an energizer stand useful with the body-
care device of Fig. 1.
Fig. 7B is a side elevation of the energizer stand shown in Fig. 7A with a
body-care device of Fig. 1 placed thereon.
Fig. 8 is a partially exploded, perspective view of an alternative skin care
device according to the present invention.
Fig. 9 is a perspective view of an attachment surface of a thermal body-
care element designed to be used with the skin care device of Fig. 8.
Fig. 10 is an end view of the skin care device of Fig. 8.
Fig. 11 is a side elevation of an energizer stand with the body-care
device of Fig. 8 placed thereon.
Fig. 12 is an electrical schematic of one embodiment of an energizer
stand and a thermal body-care element according to the present invention.
Fig. 13 is an exploded perspective view of elements of the thermal body
care element of Figs. 4-5.
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Detailed Description of the Preferred Embodiments
The challenge that has faced and continues to face developers of
commercial heated, skin care devices relates to providing sufficient heat for
a
long enough time to deliver the benefits of a heated surface with the
portability
of a manual or battery-powered device. We have discovered that it is possible
to provide the desired portability by de-coupling the power to heat the device
from the power (if any) to provide motion to the skin-contacting surface of
the
device. A number of preferred embodiments of the invention are discussed in
this section.
The first preferred embodiment may be understood by referring to Figs.
1-5 and 7. In Figs. 1-3, a cordless, handheld, skin care device 10 includes a
housing 20 that contains a motion-generating system 30 with a thermal body-
care element 40 attached thereto. The housing 20 includes one or more
gripping surfaces 21, a power switch 22, and electrical contacts 23.
The motion-generating system 30 is shown in more detail in Fig. 3. This
includes a power source, such as one or more batteries 31, coupled to a motor
32 through the power switch (element 22 shown in Figs. 1-3). The motor 32
may be coupled to the thermal body-care element 40 in a manner to transfer
vibrating motion as known to those of ordinary skill in the art. For example,
vibrations may be generated by means of an eccentrically mounted weight 33
on the motor shaft. Alternatively, the motor 32 may be coupled to the thermal
body care element 40 via gears or other transfer mechanisms to provide
rotation, reciprocation, oscillation, or other motions to the thermal body
care
element 40. The transfer mechanism may include one or more clutches to
permit the system to selectively transfer one or more of these motions, as
desired.
The thermal body-care element 40 is shown in more detail in Figs. 4-5.
Referring to Fig. 4, thermal body-care element 40 is a compact, self-contained
heating system, and it includes a heat-generating element 41 that contains a
heat source (described more fully, below) thermally coupled to a body-care
surface 42. The heat-generating element 41 includes a container 43 having at
least one thermally conductive surface 44 and one or more thermally insulating
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surfaces 45 enclosing the heat source and a thermal energy storage medium.
The container 43 is sealed to contain the heat source and thermal energy
storage medium to provide a safe heating system for use by consumers in their
homes. A supplemental body-care component 46 may be releasably coupled
In a preferred embodiment shown in detail in Figs. 5A-5E, the container
43 of the thermal body-care element 40 includes a base 401 formed of a
The heat-generating element 41 is heated by means of electric heater
404 contained within the first chamber 402. The electric heater 404 is in
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between the electric heater 404 and internal electrical contacts 410 that are
connectable to an external power source, described below.
While the thermal body-care element 40 has been shown in use with the
handheld housing 20 having the motion-generating system 30, it will be
recognized that the thermal body-care element 40 may be used, and shaped
appropriately, without the housing 20 and motion-generating system 30. The
thermal body-care element 40 can keep the geometries shown in Figs. 4 and
5A-5E, or it may take on a different form factor, such as shown in Fig. 6.
As shown in Figs. 6A and 6B, the thermal body-care element 40' is a hot
stone replica that is capable of generating heat instead of being heated in a
water bath or other heating system. Again, this thermal body-care element 40'
is an improvement over existing, natural hot stones as it is capable of
maintaining a desired temperature, as described in greater detail, below. The
thermal body-care element 40' may be generally circular when viewed from the
top or bottom (Fig. 6B), and elliptical when viewed from the side (Fig. 6A).
The
thermal body-care element 40' again has a thermally conductive body-care
surface 42', thermally insulating surfaces 45' and contains a heat-generating
element. The thermal body-care element 40' also has electrical contacts 23'
disposed on an outer surface of the thermal body-care element 40' for
selective
coupling the heat-generating element to an external electrical power source.
Referring now to Fig. 7A-7B, the skin care device 10 can be connected
to a combination stand and energizer (or "energizer stand") 50 that includes a
plug 51 to electrically connect it to an external power source, such as a
power
grid (for example, through 110V household power). While plug 51 is shown as
extending from a rear portion of the energizer stand 50, it will be recognized
that this integrated plug may be replaced by a power cord and plug
combination. The skin care device can be supported on a platform 52, and
external electrical connector 53 is arranged and configured to engage the
electrical contacts 23 (shown in Fig. 2) of the device 10 to energize the heat-
generating element. The energizer stand 50 preferably includes an energizing
circuit to control the energization of the heat-generating element. The
energizing circuit may include a timer and may be initiated by activating an
energizing circuit switch 54.
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In an alternate embodiment shown in Figs. 8-11, the housing 20" further
incorporates a mount 60 for the thermal body-care element 40". The thermal
body-care element 40" is then operatively connected to the mount 60 on the
housing 20". In one embodiment, the thermal body-care element 40" is
releasably connected to the mount 60. The mount 60 secures the thermal
body-care element 40" to the housing 20" without affecting the ability of the
thermal body-care element 40" to function as desired. For example, the mount
60 may rotate, oscillate, or provide other desired movement to the thermal
body-care element 40", or it may remain stationary on the housing 20" to
transfer desired vibrations from the motion-generating system 30. Suitable
mounts will be known to those of ordinary skill in the art. A representative,
non-
limiting list of useful mounts include snap-fit mounts; threaded mounts;
pinned,
clipped, or ringed mounts (using a removable pin, peg, clip, or ring to
immobilize the thermal body-care element in or to the mount), clamped mounts,
bayonet mounts, hook-and-loop (VELCRO) mounts, and the like.
For example as shown in Fig. 8, the handheld device 10" has a rotating
mount 60 with a receptacle 61 into which coupling elements of the thermal
body-care element 40" fit. The thermal body-care element 40" is substantially
circular and has a diameter between about 20 mm and about 60 mm. The
attachment surface 62 of the thermal body-care element 40" designed to fit
into
the receptacle 61 of the mount 60 of this embodiment is shown in more detail
in
Fig. 9. The attachment surface 62 has a plurality of engagement arms 63
extending from the attachment surface 62 in a direction away from the thermal
body-care element 40", at least one of said engagement arms comprising a
snap-fit projection 64 for engagement with recesses 65 of an associated
receptacle 61 (shown in Fig. 8). At least one spacer leg 66 extends from the
attachment surface 62 in a direction away from the thermal body-care element
40" to support it when fitted into the associated receptacle 61. The
attachment
surface 62 also has at least one key 67 extending from the attachment surface
62 in a direction away from the thermal body-care element 40" that is arranged
and configured to fit into a notch 68 in the associated receptacle 61. The
attachment surface 62 may also have one or more optional centering flange(s)
69 to improve the fit of the thermal body-care element 40" in the receptacle
61.
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Alternatively, the functions of the spacer leg(s) and the centering flange(s)
may
be combined into one or more separate structures spaced about the
attachment surface 62.
As shown in Fig. 10, the electrical contacts 23" for selective coupling the
heat-generating element to an external electrical power source are disposed on
an outer surface of the thermal body-care element 40". The skin care device
10" of this embodiment can be connected to a modified energizer stand 50" that
includes a plug 51 to electrically connect it to an external power source as
shown in Fig. 11. The skin care device can be supported on a platform, and
external electrical connector 53" is arranged and configured to engage the
electrical contacts 23" of the device 10 to energize the heat-generating
element. Again, the energizer stand 50" preferably includes an energizing
circuit to control the energization of the heat-generating element. The
energizing circuit may include a timer and may be initiated by activating an
energizing circuit switch.
In greater detail, the heat source of the thermal body-care element is
disposed within the thermal body-care element and is in thermal contact with
the thermal energy storage medium. The heat source can be any heat source
that receives energy from outside of the thermal body-care element and
provides thermal energy. Preferred heat sources include without limitation,
electrical heat sources, such as resistance heaters, positive temperature
coefficient ("PTC") heaters, cartridge heater (typically a resistance heater
in a
cartridge), and the like; electromagnetic heat sources, such as infrared
heaters,
and the like. More preferably, the heat source is an electrical heat source,
and
most preferably, the heat source is a Positive Temperature Coefficient heater
(PTC). PTC heaters are known for their self-regulating features and can
operate at a nearly constant temperature over a broad range of voltage and
dissipation conditions by increasing their resistance as temperature
increases.
PTC's can permit the omission of thermostats in certain situations since
PTC;'s increase resistance as the temperature increases. Alternatively, a
fixed resistance heater would require a more sophisticated control system in
order to maintain temperature and to overshooting its temperature set point.
This design uses both a PTC heater and a simple bimetallic temperature switch
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for control. More specifically a bimetallic "creeps action" switch was used
instead of a "snap action" in order to maintain the temperature within +/- 3
C.
Additional safety can be achieved by incorporating a thermal switch.
This provides the added safety in the event that both the bimetallic switch
was
to fail (not open) and the PTC heater somehow produced excess heat. The
thermal switch would permanently open the circuit thus removing all energy.
An example of a circuit for the energizer stand 50" and thermal body-
care element 40" of Figs. 8-11, is shown in Fig. 12. The energizer stand 50"
includes a plug 51" for selective coupling to a power grid 55. The energizer
stand 50" also includes an energizing circuit including a transformer to
convert
alternating current to direct current and an appliance leakage circuit
interrupter
(shown schematically as 56. In addition, the circuit includes a timer 57 and a
charging circuit switch 54". The energizer stand 50" is connected to the
thermal body-care element 40" through the external electrical connector 53"
and the thermal body-care element electrical contacts 23". In this schematic,
the thermal body-care element 40" includes a safety cut-off switch 409, a
thermal switch 408, and a PTC heater 404. An optional indicator light 58 is
also shown.
To generate heat, the heat source requires energy to be delivered from
outside of the thermal body-care element. One traditional method may include
wire leads or other metallic connections from the heat source to the outside
of
the thermal body-care element. Other possibilities include electromagnetic
induction. In one preferred embodiment, wire leads extend from the heat
source to one or more couplers disposed on the thermal body-care element
that can engage a connector of an outside power source. This power source
may be a conduit through the housing to electrical contacts disposed thereon.
These electrical contacts in turn are connected to an external power source,
such as household electrical supply through a power plug.
Again, the thermal body-care element includes a container includes a
base formed of a thermally insulating material and a thermally conductive cap.
The container may also include additional thermal insulating surfaces, such as
the external sleeve. A representative, non-limiting list of useful thermally
insulating materials includes polymeric and other organic materials, ceramic
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materials, and the like. Preferred thermally insulating materials have low
thermal and electrical conductivity, such as polymers and ceramics, and are
dimensionally stable.
Thermally conductive materials useful for the cap and other thermally
conductive elements of the container may be formed of any thermally
conductive material. A representative, non-limiting list of useful thermally
conductive materials includes thermally conductive polymeric materials,
metals,
and the like. Preferred thermally conductive materials include thermally
conductive polymers that have low electrical conductivity.
The thermal energy storage medium is used to store the heat generated
by the heat source while it is connected to the external power source and to
release the heat to the body-care surface during use. Preferably, the thermal
energy storage medium has a high heat storage density. There are three main
physical ways for thermal energy storage: sensible heat, phase change
reactions and thermo-chemical reactions. Sensible heat storage is based on
the temperature change in the material and the unit storage capacity is equal
to
heat capacitance x temperature change. Sensible heat systems generally have
a large thermal mass or require a large temperature range.
Phase change heat storage results when a material changes its phase
while heating; the heat stored in the phase change is dissipated during
cooling
of the material as the phase change is reversed. The storage capacity of the
phase change materials is equal to the phase change enthalpy at the phase
change temperature + sensible heat stored over the whole temperature range
of the storage.
Phase change systems generally have a much higher energy storage
density than sensible heat storage systems.
Therefore, one preferred form of thermal energy storage medium is a
phase change material. Preferred phase change materials have high latent
heat of fusion per unit mass (increases energy storage density), high specific
heat that provides additional sensible heat storage effect, high thermal
conductivity, high density, and most significantly, a melting point at the
desired
operating temperature range. Additional considerations include safety (non-
flammable, non-poisonous, non-explosive), non-corrosive, no chemical
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decomposition. Classes of phase change materials include organic and
inorganic materials. Organic materials include, without limitation, waxes such
as paraffins (C,H2n+2) and fatty acids (CH3-(CH2)2,)-COOH) such as lauric
acid,
stearic acid, pentaglycerine. These materials generally are chemically stable,
have a high heat of fusion, are safe, are non-reactive, and are recyclable.
However, they may suffer from relatively low thermal conductivity in their
solid
state, their volumetric latent heat storage capacity is relatively low; they
may be
flammable. In particular, paraffin waxes are available from many commercial
sources. These waxes generally do not have a distinct melting point
temperature. Rather, they have a melting point range. For example, one
material available from Strahl & Pitsch, Inc. West Babylon, New York, USA has
a melting point range (Melting Point Open Cap. Tube USP Class II) of 122-127
F (50-53 C). Other paraffin waxes may have a melting point range of up to
69-73 C.
One issue identified above in phase change material systems is
significant change in volume in during the phase change and/or chemical
reaction. Therefore, it may be desirable to employ a "pressure block" 411
(shown in Fig. 5C) or material that is capable of expanding or contracting to
volume changes that can be created by an air pocket or the thermal energy
storage medium. The pressure block 411 can be a separate item, attached to
the cup or an integrated into the molding process of the thermal body care
element. Another purpose of the pressure block is to help maintain the thermal
energy storage medium in a specific location such as against the electric
heater
or on one side of the thermal body care element.
The thermal energy storage medium can be selected for its operating
temperature range. Generally, a sensible heat system will be operable over a
very broad temperature range ¨ a range over which it does not change phase.
A phase change system will have particularly usefulness when the operating
temperature range spans the phase change temperature ¨ especially a phase
change temperature near and/or slightly above the desired heat application
temperature
The amount of thermal energy storage medium used in the thermal
body-care element will be determined by the available volume and the desired
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heat capacity of the thermal body-care element. In one preferred embodiment
for use in a handheld device having a motion-generating system may include
about 1 to about 5 g of a wax or wax mixture. More preferably, this
embodiment may include about 1 to about 3 g of the wax or wax mixture.
In alternative embodiments, such as the hot stone shown in Figs. 6A and
6B, described above, the amount of wax may be increased. For example, one
size of hot stone may include about 2 to about 12 g wax or wax mixture, and
more preferably, between about 3 and about 10 g of the wax or wax mixture.
Supplemental body-care component 46 may be a pad or other element
that is capable of transferring heat from the heat-generating element 41 and
that is placed in association with the body-care surface 42. The supplemental
body-care component 46 may be mated to the body-care surface 42 and may
include a securing surface for contacting a coupling structure 47 of the body-
care surface 42 to temporarily secure the supplemental body-care component
46 to the body-care surface 42 during operation of the device. As discussed
above, the securing surface may be engaged by the coupling structure.
Alternatively, the supplemental body-care component 46 may be held in
place during operation of the device via any number of suitable mechanical or
magnetic components (not shown), such as clamps, snaps, adhesive, and the
like may be used to facilitate the attachment and detachment of the
supplemental body-care component 46.
In one preferred embodiment, the supplemental body-care component
46 is or includes a porous material, such as a porous sheet. The pores may be
capable of transporting liquid from within the supplemental body-care
component 46 to a skin-contactable surface thereof. The sheet may be fibrous
and/or film-based (e.g., may include fibrous and/or plastic film materials,
such
as one or more layers of these materials). The layers of material may be
relatively rigid or relatively compliant and may serve one or more functions
such as enhancement of friction by the skin-contactable surface on the skin,
transport of sebum away from the skin, transport of various cleansers and/or
benefit agents, as described below, towards the skin so that they may provide
some benefit thereto, among other functions. Suitable fibrous materials that
may be used include those based from organic polymers such as, for example,
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polyester, polyolefin, rayon, cellulose such as from wood pulp, bicomponent
fibers, and other combinations thereof. The fibers are woven or non-woven and
arranged in a network via, for example, a carding process, and bonded via, for
example, an air-through bonding, chemical bonding, or an embossing process.
The layer of fibrous material may include binders such as organic resins or
other ingredients to manipulate the mechanical or fluid management properties
thereof. The layer of fibrous material may have a basis weight that supports
the
layer to maintain its mechanical integrity for one or more uses of the
supplemental body-care component 46. The basis weight may be, for example,
between about 10 grams per square meter (gsm) and about 100 gsm, such as
between about 40 gsm and about 60 gsm.
Alternatively, the supplemental body-care component 46 may have
massaging protrusions, oriented fibers (such as a brush or dilour surface),
and/or a coated surface. However, it may be desirable to have the massaging
protrusions and/or coated surface be the body-care surface 42, itself.
In one embodiment of the invention, the supplemental body-care
component 46 includes one or more cleansers and/or benefit agents. Various
cleansers are known to those of ordinary skill in the art, and the chosen
cleanser (if any) is not critical to the operation of the present invention.
What is
meant by an "benefit agent" is a compound (e.g., a synthetic compound or a
compound isolated from a natural source) that has a cosmetic or therapeutic
effect on the skin including, but not limited to, lightening agents, darkening
agents such as self-tanning agents, anti-acne agents, shine control agents,
anti-microbial agents, anti-inflammatory agents, antifungals, anti-parasite
agents, external analgesics, sunscreens, photoprotectors, antioxidants,
keratolytic and exfoliating agents, surfactants, moisturizers, nutrients,
vitamins,
energy enhancers, anti-perspiration agents, astringents, deodorants, hair
growth inhibitors, anti hair-loss agents, hair growth promoters, hair
removers,
skin-firming agents, anti-callous agents, anti-aging agents such as anti-
wrinkle
agents, skin conditioning agents, allergy inhibitors, antiseptics, external
analgesics, antipruritics, antihistamines, antiinfectives, anticholinergics,
vasoconstrictors, vasodilators, wound-healing promoters, peptides,
polypeptides, proteins, deodorants, anti-perspirants, film-forming polymers,
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counterirritants, enzymes, enzyme inhibitors, poison ivy treatment agents,
poison oak treatment agent, burn treatment agents; anti-diaper rash treatment
agents; prickly heat agents; botanical extracts including herbal extracts;
flavenoids; sensates; anti-oxidants, keratolytics; sunscreens; and anti-edema
agents; and combinations thereof.
What is meant by a "botanical extract" is a blend of two or more
compounds isolated from a plant. Examples of botanical extracts include, but
are not limited to legumes such as Soy, Aloe Vera, Feverfew, Hedychium,
Rhubarb, Portulaca, Cedar Tree, Cinnamon, Witch Hazel, Dandelion, Chinese
Angelica, Turmeric, Ginger, Burnet, Houttuynia, Coix Seed, and Thyme.
In one embodiment of the invention, the benefit agent is designed for
application on the forehead region and includes, but is not limited to: oil-
control
agents such as titanium dioxides, alcohols, botanical extracts, and talc; pore
refining agents such as alpha-hydroxy acids, beta-hydroxy acids, and enzymes;
anti-acne agents such as benzoyl peroxide, salicylic acid, trichlorcarban,
triclosan, azelaic acid, clindamycin, adapalene, erythromycin, sodium
sulfacetamide, retinoic acid, and sulfur; oil-absorbing agents such as
titanium
dioxides and clays; shine control agents such as silicones, alcohols, talc,
and
clays; dark spot reduction agents such as vitamin C, hydroquinone, botanical
extracts, alpha-hydroxy acids, beta-hydroxy acids, and retinoids; and/or
wrinkle/fine-line reduction agents such as retinoids, alpha-hydroxy acids, and
enzymes.
In another embodiment of the invention, the benefit agent is designed for
application around the mouth and includes, but is not limited to:
hydration/moisturization agents such a glycerin, silicone, glycols, botanical
extracts, and esters; pore-refining agents; anti-acne agents; vasodilators
such
as niacinamide and horsechesnut extract; vasoconstrictors such as caffeine
and botanical extracts; skin-lifting agents such as (e.g., copper containing
peptides, dimethyaminoethanol, and polymers); skin-firming polymers;
wrinkle/fine-line reduction agents; depigmenting/skin lightening agents such
as
vitamin C, hydroquinone, botanical extracts, alpha-hydroxy acids, beta-hydroxy
acids, retinoids, arbutin, and kojic acid; and depilatory/hair reducing agents
such as soy extracts, n-acetyl-cysteine, and isoflavones.
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In order to use the system of the present invention, a user may connect
the energizer stand 50 to household current through plug 51. In a preferred
embodiment, the user would power the system by pressing the energizing
circuit switch 54 to enable electrical current to flow into the thermal body-
care
element 40. When the thermal body-care element 40 is fully energized to
provide the desired heat, a signal may alert the user to remove the handheld
skincare device 10 from the energizer stand 50.
If desired, the optional, supplemental body-care component 46 may be
applied to the body-care surface 42 of the thermal body-care element 40. In
addition, the supplemental body-care component 46 may be moistened or
wetted by running under tap water. The supplemental body-care component
may be applied any time before use. For example, the supplemental body-care
component 46 may be applied before energizing the thermal body-care
element 40, or it may be applied after the thermal body-care element 40 has
been fully energized and heated, immediately prior to application to the
user's
skin.
The motion-generating system 30 can be activated by the user, and the
skin care device 10 can be moved about in contact with the user's skin for the
desired effect.
One way to make the thermal body-care element 40 of Fig. 5 is shown in
Fig. 13. A thermally-insulating, cylindrical cup 401 having two chambers is
formed of plastic and has external threads. A PTC heater 404 is secured to the
plastic base of the first chamber 402.
A thermally conductive cap 406 has walls 406a arranged and configured
to line the first chamber of the cup 401 when assembled. A flange 406b
extends from the top surface of cap 406 into the second chamber 403 of the
cup 401. A thermal switch 408 and safety cut-off switch 409 are secured to the
flange to enable them to sense and control the temperature in the first
chamber
402 via the thermal conductivity of the cap 406.
A gasket 48, such as an o-ring, is disposed on the top of the cup 401,
and the cap 406 with the thermal switch and safety cut-off switch mounted on
the flange is placed on the cup 401. The heater, thermal switch and safety cut-
off switch are electrically interconnected, e,g, via insulated wires that pass
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through the wall 401a dividing the two chambers, in an electrical circuit. The
electrical circuit also has electrical contacts 23" 410 to engage the external
power source.
An optional coupling structure 47, such as plastic hooks may be adhered
to a portion of the body-care surface 42 of the cap 406, and a threaded
external
sleeve 407 of the thermal body-care element 40 is screwed onto the external
threads of the cup 401 to complete the container 43. A thermal energy storage
medium 405, such as wax, can be injected through a port into the enclosed
first
chamber, and the port can be sealed to complete the assembly.
The foregoing is only one way to make the thermal body-care element of
the present invention. Persons of ordinary skill will recognize various
alternatives of assembling the inventive thermal body-care element.
Examples
Example 1
The following is an example of the determination of the mass of paraffin
wax needed to provide a desired amount of heat for a predetermined period of
time. For this example, the values are approximate and rounded to no more
than 2 significant figures. In this example, we show a process to determine
the
system necessary to heat a wetted pad (2 grams of water held by a small
nonwoven pad) from 20 C to 40 C and providing that heat for 120 seconds.
Based upon the mass of water, temperature range, duration of heat and an
assumed 50% efficiency in transferring heat to the wetted pad, we determined
that 450 Joules ("J") of energy was required.
In this example, we used a paraffin wax having a specific heat of about
2000 J/(kg- C) in the liquid phase, about 1000 J/(kg- C) in the solid phase,
and
a heat of fusion of about 210000 J/kg, and a melting point range of about 53-
57
C. We assumed an initial liquid phase temperature of about 60 C, and a final
solid phase temperature of about 40 C when used to warm the wetted pad. In
order to provide the 450 J to the pad, we determined that about 0.002 kg (2 g)
of the wax was required.
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In order to store 450 J of thermal energy in 2 g of the paraffin wax, we
determined the amount of electrical energy necessary to heat 2 g of the
paraffin
wax from an initial solid phase temperature of 20 C to a final liquid phase
temperature of about 55-60 C. In order to minimize the electrical energy
required, we chose to maximize thermal transfer efficiencies by using an
internal electric heater surrounded by the wax. Based upon assumed operating
efficiencies and assumed thermal transfer efficiencies, we determined the
electrical energy required to store 450 J of thermal energy in 2 g of the wax
to
be about 1000 J. Finally, we set a target time to heat the wax of 90 seconds.
Therefore, the electrical power necessary to provide and store the heat energy
is 1050 J/90 s, or about 12 Watts ("W").
In order to determine whether the energy source to provide the
necessary electrical power [Power (W) = Voltage (V)* Current (I)] could have
been provided in the cordless, handheld skin-care device, we made the
following assumptions and calculations. Assuming a 1.5 V single cell battery
is
used, the current necessary to generate 12 W would be:
12 W = 1.5 V * I,
or
I = 12 W / 1.5V,
or
I = 8 Amps
As AA batteries operate in the range of milliamps ("mA"), a large number
of AA batteries would be required. Larger capacity batteries are too large and
heavy and/or too expensive. Therefore, an external power source, such as at
120 VAC, was selected. At 120 VAC, the required current would be orders of
magnitude lower:
1= 12 W/ 120 V,
or
I = 0.1 Amps (100 mA)
Thus, the external power source permits the use of low currents and
consequently smaller components.
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Example 2:
The following is an example of the determination of the mass of paraffin
wax needed for an embodiment of a hot stone for placement on skin for 10 to
30 minutes.
Again, we used a paraffin wax having a specific heat of about 2000
J/(kg- C) in the liquid phase, about 1000 J/(kg- C) in the solid phase, and a
heat of fusion of about 210000 J/kg, and a melting point range of about 53-57
C. We assumed an initial liquid phase temperature of about 60 C, and a final
solid phase temperature of about 40 C when used to warm the wetted pad.
We also assumed that the heat energy was transferred to the skin at 1 J/sec or
1 W. Thus, for a duration of 10 minutes, 600 J of heat energy was required.
For a duration of 30 minutes, 1800 J was required. This results in a mass of
wax of about 2.5 g (10 minute application) to about 8 g (30 minute
application).
Of course, the electrical power required to heat and store the heat in the wax
(and larger container) would be increased from Example 1.
The specification and embodiments above are presented to aid in the
complete and non-limiting understanding of the invention disclosed herein.
Since many variations and embodiments of the invention can be made without
departing from its spirit and scope, the invention resides in the claims
hereinafter appended.
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