Patent Application
20130085422
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, U.S. 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 A1, 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, U.S. 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., U.S. 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 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.
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. This was accomplished in a handheld device for application to a skin surface of a human or animal. The device includes a housing arranged and configured for gripping by a human hand, a body-care surface operatively connected to the housing arranged and configured to transfer heat and motion to the skin surface, a motion-generating system contained within the housing, and a heat-generating element thermally coupled to the body-care surface. The motion-generating system includes a motor operatively coupled to the body-care surface to impart motion thereto and electrically coupled to an internal electric power source contained within the housing. The heat-generating element includes a container having at least one thermally conductive surface enclosing an electric heater in thermal contact with a thermal energy storage medium and an electrical connection for selective coupling to an external electrical power source.
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
The motion-generating system 30 is shown in more detail in
The thermal body-care element 40 is shown in more detail in
In a preferred embodiment shown in detail in
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 thermal contact with the thermal energy storage medium 405 also contained within first chamber 402. Thus, when the electric heater 404 is energized, it heats the thermal energy storage medium 405. The electric heater 404 is preferably controlled, at least in part, by a thermal switch 408, and the heating system is preferably protected from overload by a safety cut-off switch 409. These two switches are mounted in thermal contact with the flange 406b of the cap 406 to enable them to sense the temperature of the first chamber 402, during use, and they are arranged along the electrical power supply circuit 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
As shown in
In an alternate embodiment shown in
For example as shown in
As shown in
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 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
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 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×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 decomposition. Classes of phase change materials include organic and inorganic materials. Organic materials include, without limitation, waxes such as paraffins (CnH2n+2) and fatty acids (CH3—(CH2)2n)—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, N.Y., 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
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 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
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, 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, 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.
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
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 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.
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.
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/1.5 V,
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:
I=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.
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.
