Hair styling device

Abstract

A hair styling device includes: a core having a high thermal conductivity; an outer wall spaced apart from the core, the outer wall including an outer surface on which a portion of the user's hair may be wound; and a phase change material disposed between the core and the outer wall, the phase change material for releasing heat to the portion of the hair of the user via the outer surface in use.

Description

Technical Field

[0001] The present invention relates to a hair styling device and a kit of parts for styling a user's hair. Background Art

[0002] Hair curlers are commonly used to process or style hair, such as to set or curl hair. Applying heat to a user's hair changes the hydrogen bonds within the hair keratin. Applying heat is therefore commonly used to curl or wave hair.

[0003] Typically, a hot hair curler is preheated before being inserted into the hair, for example on a base. Once inserted into the user's hair, as the hot hair curler cools, the heat stored in the thermal mass of the hot hair curler is transferred to the hair, thereby styling the hair. Summary of the Invention

[0004] According to a first aspect, there is provided a hair styling device comprising: a core having a high thermal conductivity; an outer wall spaced apart from the core, the outer wall including an outer surface around which a portion of a user's hair can be wound; and a phase change material disposed between the core and the outer wall, the phase change material for releasing heat to the portion of the user's hair via the outer surface during use.

[0005] Advantageously, including a phase change material in a hair styling device can provide improved styling performance during use compared to currently known hair styling devices in the art. As used herein, a phase change material can be any material that releases or absorbs energy during a phase change (phase transition). Compared to traditional hair styling devices, a phase change material can thus store more energy per unit volume. In some examples, the phase change material can also melt, thereby reaching the operating temperature faster than traditional hair styling devices, such that the charging time (the time taken for the hair styling device to be ready for use) is reduced. This can reduce the power consumption of the hair styling device or kit, which can be environmentally beneficial.

[0006] The latent heat storage of the phase change material can maintain the temperature on the outer wall surface for a longer time than traditional hair styling devices, which can improve the energy transfer from the hair styling device to the portion of the hair. In other words, most of the energy stored in the phase change material is released while the phase change material maintains its temperature. Compared to traditional hair styling devices, the phase change material can also allow for a reduction in the weight of the hair styling device.

[0007] During use, the core can surround a heat source, such as a heating element on a base. Of course, embodiments where the heat source is part of the hair styling device can also be envisaged. In these cases, the base can provide an electrical connection to allow the heat source to be electrically heated or the heat source may not require a base (i.e., a switch activated within the contained device). In this way, the heat source can transfer heat to the core.

[0008] The core has a high thermal conductivity. That is, compared to a core with low thermal conductivity, heat transfer occurs at a higher rate. Thus, the core is efficient in heat transfer. A core with high thermal conductivity can thus speed up the time to heat and melt the phase change material, and in some cases, can reduce the power required to heat the phase change material. In some embodiments, the core of the hair styling device can have a thermal conductivity of at least 100 W / mK at 20 °C. To this end, the core can be a metallic material, such as aluminum, or any other suitable electrically conductive material.

[0009] The core can be centered within the hair styling device. That is, the core can be positioned at an equal distance from the outer wall. In some examples, the core is a tube arranged concentrically with respect to the outer surface. The central placement of the core can allow for more uniform heating of the phase change material. Although in some examples, the core can be positioned off-center, for example to unevenly distribute the weight of the hair styling device, this can allow the user to use it more comfortably.

[0010] In some examples, the diameter of the core of the hair styling device can be less than the uniform distance between the core and the outer wall. The phase change material can thus have a thickness greater than the core diameter. This can allow the hair styling device to store the maximum amount of energy while balancing the time it takes to charge the hair styling device.

[0011] In use, the portion of the user's hair is heated by the phase change material that releases heat energy, thereby heating the outer wall, which has an outer surface around which that portion of the hair is wrapped. The outer surface can thus be adapted to receive a portion of the user's hair. For example, the outer surface can include a flocked layer.

[0012] In some examples, the hair styling device further includes a member for transferring heat from the core to the phase change material, the member being located between the core and the outer wall. The core heats the phase change material by radiating heat energy into the phase change material. Since the core is located at the center of the hair styling device, the phase change material closest to the core will melt faster than the phase change material that is farther away (and closer to the outer wall). The member can be located between the core and the outer wall, in other words, extending through the phase change material. The member can provide a larger surface area to radiate heat through the phase change material. The member can thus provide the advantage of improving the thermal distribution in the phase change material. The phase change material across the entire hair styling device can melt faster and / or more evenly, which in turn can accelerate the melting time (the time to completely melt) of the phase change material, which can reduce the charging time (the time to get ready for styling) of the hair styling device. The member can be completely located within the phase change material and thus not in contact with the core and / or the outer wall. In other examples, the member can be in contact with the core and / or the outer wall. In some cases, the member is integral with one or both of the core and the outer wall.

[0013] In some examples, the member extends from the core towards the outer wall. The contact between the member and the core can improve the heat transfer between the core and the member, as the heat transfer occurs by conduction from the core to the member. This in turn can accelerate the melting time of the phase change material, thereby reducing the charging time of the hair styling device.

[0014] In some examples, the member extends from the core by more than half of the distance from a first point on the core to a second point on the outer wall that is opposite the first point. For example, the core and the outer wall can be concentric tubes. In this case, the member can extend radially from the core towards the outer wall, and the distance from the first point to the second point can be the distance in the radial direction. As described above, a member with a larger surface area for contacting the phase change material can increase the rate of melting the phase change material. A member that extends at least half way between the core and the outer wall can accelerate the melting time of the phase change material within the hair styling device. In some examples, the distance between one end of the member and the outer wall is less than 1 mm. A hair styling device having at least some space between the end of the member and the outer wall can prevent the member from promoting conductive heating from the core to the outer wall, which may result in non-uniform heating on the outer surface.

[0015] In some examples, the member includes a first part and a second part, where the first part and the second part are separated from each other. A member that includes two (or more) parts can give a substantially branched configuration, which can provide a greater surface area of the member exposed to the phase change material when compared to a member having a single linear body. Thus, more of the phase change material may come into contact with a part of the member, which may speed up the melting time.

[0016] In some examples, the member includes a plurality of holes. When at least some of the phase change material is in liquid form, it can flow through the member via the plurality of holes. The flow of the phase change material during the melting process means that the phase change material may also undergo convective heat transfer, for example in regions away from the phase change material in contact with the member. Thus, including holes through the member can promote more flow of the phase change material compared to a solid member. Alternatively or additionally, as the phase change material solidifies during cooling, its volume decreases. In this way, the phase change material can shrink into the holes, which can have the advantage that the member is subjected to less stress when the phase change material solidifies around the member. The holes can be distributed around the member. The distribution can be uniform over the member, or more concentrated in regions that are subjected to higher stress relative to the rest of the member (such as the point where the member is divided into the first and second parts). These holes can have different sizes throughout the member; for example, this can be optimized according to the relatively higher stress regions with larger holes. In some examples, the member can be formed of a mesh. In other examples, the member can form a porous structure with the phase change material located around it.

[0017] In some examples, the hair styling device includes a plurality of members distributed around a core, the plurality of members being configured to transfer heat from the core to a phase change material. The plurality of members distributed around the core can improve the overall heating effect of the hair styling device. For example, by spacing the plurality of members around the core, a high surface area capable of heating the phase change material can be advantageously allowed. In some examples, the plurality of members may be easier to manufacture than a single member. That is, a single member spiraling around the core may be more difficult to manufacture on a production line compared to a plurality of planar disks spaced along the length of the core. The plurality of members can have different features. For example, every other member can have a hole passing through it. In some examples, all of the plurality of members incorporate one or more of the above features.

[0018] In some examples, each of the plurality of members has a length corresponding to the length of the core, and the lengths of the plurality of members extend parallel to the longitudinal axis of the core. The lengths of the plurality of members extending parallel to the longitudinal axis of the core can allow two adjacent members to at least partially segment the phase change material. In examples where the members do not extend all the way to the outer wall, the segments of the phase change material can of course be connected. For example, the plurality of members can be arranged around the core in a toothed configuration. This can have the advantage of maintaining heat convection within the liquid phase change material, since each segment of the phase change material can still have convective heating.

[0019] In some examples, each of the plurality of members includes a disk, and each disk is spaced apart from an adjacent disk along the length of the core. Two adjacent disks can define a series of phase change material layers along the length of the core. In examples where the members do not extend all the way to the outer wall, these layers can of course be connected. Dividing the phase change material into a plurality of layers and advantageously into smaller layers can help reduce separation of the phase change material (such as separation of additives contained within the phase change material, etc.) during the life of the hair styling device, and this can extend the life of the hair styling device.

[0020] In some examples, the plurality of members are uniformly distributed around the core. The uniform distribution of the plurality of members can increase the distribution of heat within the hair styling device relative to the core. In some examples, the plurality of members can be arranged symmetrically with respect to the core.

[0021] In some examples, at least one of the plurality of members extends from the core to the outer wall. In addition to the phase change material, the member can also conduct heat to the outer wall. In some cases, this can be beneficial for reducing the charging time of the hair styling device.

[0022] In some examples, each of the plurality of members is the same. Having the same members means that each member has a substantially uniform phase change material heating curve relative to the other members. This can help maintain uniform heating across the entire phase change material.

[0023] In some examples, the phase change material has a melting temperature of at least 50 °C. Having a melting temperature of at least 50 °C can result in the temperature achievable at the outer surface being optimal for styling a user's hair. That is, the temperature of the outer surface may be hot enough to change the shape of the hair (e.g., curl). The melting temperature can be at least 70 °C.

[0024] In some examples, the phase change material has a latent heat of at least 150 kJ / kg. The latent heat of the phase change material within this range can provide the hair styling device with the advantage of an optimized heat storage weight ratio.

[0025] In some examples, the phase change material is an organic material. Organic phase change materials may be stronger and less expensive than inorganic materials. Some example organic phase change materials can be CT74, RT111 HC, or erythritol, or a combination thereof. CT74 has a melting temperature of 75 °C and a latent heat of 226 kJ / kg. RT111 HC has a melting temperature of 111 °C and a latent heat of 210 kJ / kg. Erythritol has a melting temperature of 118 °C and a latent heat of 340 kJ / kg.

[0026] In other examples, the phase change material is an inorganic material. Some inorganic materials may have a higher latent heat than organic phase change materials. In some examples, the phase change material can be a mixture of organic and inorganic materials. The member can divide the phase change material into layers (or wedges), and each layer (or wedge) can contain a different phase change material. These different phase change materials can be solely organic, solely inorganic, or a combination thereof.

[0027] In some examples, the outer wall has a lower thermal conductivity than the core. The outer wall having a lower thermal conductivity than the core can provide a degree of protection for the user, such as by reducing the risk of burns at the outer surface. For example, the outer surface can have a coating with a lower thermal conductivity than the core.

[0028] In some examples, the hair styling device further includes a heat source thermally coupled to the core. For example, the heat source can be at least partially disposed within the core. That is, the heat source can extend through the core such that the core surrounds at least a portion or all of the heat source. The core can be in contact with the heat source such that heat from the heat source is transferred to the core by conduction. The heat source can be a heating element, such as a resistive heater.

[0029] According to a second aspect of the present invention, there is provided a hair styling device comprising: a core having a high thermal conductivity; an outer wall spaced apart from the core, the outer wall including an outer surface around which a portion of a user's hair can be wrapped; and a plurality of members disposed around the core, each of the plurality of members extending towards the outer wall, wherein the hair styling device includes a phase change material disposed between the core and the outer wall, the phase change material being configured to release heat to the portion of the user's hair via the outer surface during use, wherein the plurality of members extend through at least some of the phase change material. The heat released to the user's hair can be maintained at a constant temperature (defined by the phase change temperature of the phase change material used) for a period of time.

[0030] According to a third aspect of the present invention, there is provided a hair styling kit comprising: the hair styling device as described above; and a base to which the hair styling device is configured to be removably coupled, wherein the base is configured to heat the core of the hair styling device via a heat source when the hair styling device is coupled to the base. The heat source can be part of the hair styling device or part of the base. The heat source can be a heating element, such as a resistive heater.

[0031] In some embodiments, the base includes at least one cavity configured to receive at least one hair styling device therein. The base having a cavity can make the kit compact when charging or storing the hair styling device. The cavity can partially enclose the hair styling device, that is, a portion of the hair styling device can be exposed during charging. The hair styling device can have a gripping portion exposed from the cavity, etc., such that the outer surface is within the cavity. In some embodiments, the base can include a mechanism for lifting at least a portion of the hair styling device out of the cavity such that the cavity can be fully enclosed during charging while being easily removable.

[0032] In some examples, the cavity includes a heat-insulating wall such that when the hair styling device is coupled to the base, the cavity insulates the hair styling device. The walls of the heat-insulating cavity can help retain the heat within the cavity, thereby helping to maintain the temperature of the outer surface of the outer wall. In other words, insulating the cavity when the hair styling device is being charged can reduce heat loss to the surrounding environment.

[0033] In some embodiments, the base is configured to receive at least one hair styling device in an upright position relative to the base. Heating the core of the hair styling device when the hair styling device is in an upright position (where the longitudinal axis of the core is substantially perpendicular to the bottom of the cavity) can reduce the charging time compared to a horizontal configuration. In particular, the time taken for the phase change material to completely melt can be reduced. For example, relative to a horizontal configuration, the vertical position can allow improved convective heating within the partially melted phase change material. Receiving the hair styling device in an upright position can also reduce the footprint of the base, requiring less material and thus reducing costs.

[0034] In some examples, the base includes a controller configured to maintain the heat source at an optimal temperature for melting the phase change material. The controller can maintain the temperature of the core, for example, by starting and stopping the heat source, and / or maintain the temperature of the heat source at a constant temperature, for example, by controlling the current flowing through the resistive element. To this end, the controller can include a temperature sensor and / or a feedback loop. The controller can be, for example, a PID controller.

[0035] The optimal temperature can be specific to the phase change material, as different phase change materials can have different melting temperatures. The optimal temperature can be at least 20 °C higher than the melting temperature of the phase change material. In some examples, the controller can maintain the temperature within a range that is at least 20 °C higher than the melting temperature of the phase change material and at least 10 °C lower than the flash point of the phase change material.

[0036] In some examples, the hair styling kit includes a plurality of hair styling devices. By providing a plurality of hair styling devices, the user can be able to style all of their hair at once, which can improve the convenience of the user using the kit. For example, the kit can include between 4 and 16 hair styling devices.

[0037] In some examples, the base includes a plurality of cavities corresponding to the plurality of hair styling devices. The hair styling devices within the kit can have different diameters and / or shapes such that in use they can style different portions of the hair. For example, the hair styling kit can include 3 to 7 devices that have a diameter smaller than the diameter of the remaining devices within the kit for the front portion of the user's hair.

[0038] Other features and advantages of the present invention will become apparent from the following description of the preferred embodiments of the invention with reference to the drawings, which are given by way of example only. Unless otherwise stated, the above features should be considered to be combinable with each other. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1a A perspective view of an example hair styling device according to the present invention is shown;

[0040] Figure 1b Shows Figure 1a a plan view of;

[0041] Figure 2 A perspective view of an example hair styling device according to the present invention is shown, including one component;

[0042] Figure 3a A perspective view of an example of a hair styling device according to the present invention is shown, including a plurality of components;

[0043] Figure 3b Shows Figure 3a a plan view of the hair styling device of;

[0044] Figure 3c A perspective view showing another example of a hair styling device according to the present invention, including a plurality of components;

[0045] Figure 3d A perspective view showing yet another example of a hair styling device according to the present invention, including a plurality of components;

[0046] Figures 4a to 4d Shows having Figure 3d Melting of the phase change material with the component arrangement of;

[0047] Figure 5a A perspective view showing an example base for charging a plurality of styling devices according to the present invention; and

[0048] Figure 5b Shows a base having a plurality of styling devices according to the present invention Figure 5a of.

[0049] Throughout the specification and drawings, the same numbers refer to the same components. Detailed Description

[0050] Examples of hair styling devices and associated docking stations will now be discussed. In the following description, the hair styling device is a curling iron, but it should be understood that other hair styling devices may also be contemplated. The hair styling device has two different phases in use; a charging phase and a styling phase. As used herein, the charging phase refers to the input of thermal energy into the hair styling device, thereby raising the temperature of the device to and above the melting point of the phase change material in order to potentially store energy. The styling phase refers to the phase in which the user uses the hair styling device to style a portion of the hair.

[0051] Now referring to Figure 1a and 1b , an example hair styling device 100 is shown. The hair styling device 100 includes a core 110 and an outer wall 120. The core 110 and the outer wall 120 have an upper wall 112 and a lower wall 114 extending therebetween. A phase change material 130 is located between the core 110 and the outer wall 120 and between the upper wall 112 and the lower wall 114.

[0052] The core 110 is centrally located within the hair styling device 100, and the outer wall 120 is concentrically arranged relative to the core 110. The core 110 is tubular. Thus, the core 110 can receive a heat source therein (see, for example, Figure 5a 660a in). The core 110 is formed of aluminum, which has a high thermal conductivity of 236 W / mK at 0 °C, which means it is a good heat conductor.

[0053] The outer wall 120 surrounds the core 110 while being spaced apart from the core 110. The outer wall 120 has an outer surface 122 which, in use, receives a portion of the user's hair. In this example, the outer surface 122 has a flocked layer (not shown) which can help to better grip the hair.

[0054] The outer wall 120 has a high thermal conductivity such that heat is effectively transferred through the outer wall 120 to the outer surface 122. However, the thermal conductivity of the outer wall 120 is less than that of the core 110. In this way, the outer wall 120 can provide some thermal insulation for the phase change material 130 to reduce rapid heat loss. The upper wall 112 and the lower wall 114 are formed of a heat insulating material, which can reduce heat loss from any non-styling areas.

[0055] The phase change material 130 is located between the core 110 and the outer wall 120 and has a constant thickness over the entire hair styling device 100. In this example, the region of the phase change material contacts the core 110 or the outer wall 120 such that the entire phase change material (i.e., when viewed as a whole) contacts both the core 110 and the outer wall 120. However, an intermediate layer of a thermally conductive material is contemplated between the core 110 and the outer wall 120, such as two layers of phase change material arranged concentrically and separated by an intermediate wall.

[0056] The phase change material 130 is a material capable of storing and then releasing energy as heat during a solid-to-liquid phase change. In addition, the phase change material 130 is a material having a melting point and a latent heat, which is suitable for the end use of styling a portion of the user's hair. To this end, the phase change material 130 has a high latent heat of at least 150 kJ / kg. The melting temperature of the phase change material 130 is at least 70 °C. In this example, the phase change material 130 is erythritol, which has a melting temperature of 118 °C and a latent heat of 340 kJ / kg.

[0057] In use, the core 110 is heated by a heat source, for example by contacting the heat source. The heat source and its operation are described in more detail below with reference to Figures 4a to 4d The core 110 radiates heat to the phase change material 130. The phase change material 130 thus increases in temperature, storing the thermal energy as sensible heat. Once the phase change material 130 reaches the melting temperature, the phase change material stops increasing in temperature and melts, storing the thermal energy as latent heat. The region of the phase change material 130 closest to the core 110 will be heated and melted first because they are closest to the heat source and thus at a higher temperature. The phase change material 130 thus has a temperature gradient where the hottest region is closest to the core 110 and the colder region is closest to the outer wall 120, such that the phase change material 130 melts in a radiation manner away from the core 110. The melted phase change material 130 also undergoes some convective heating, which can more quickly increase the temperature at the boundary between the melted phase change material 130 and the solid phase change material 130.

[0058] Once the phase change material 130 has melted, it continues to increase in temperature, storing energy again as sensible heat energy. The phase change material 130 continues to be heated until the hair styling device is removed from the heat source (or reaches equilibrium with the heat source).

[0059] During this charging process, the outer wall 120 is continuously heated by the phase change material 130, which in turn heats the outer surface 122. The temperature of the outer wall 120 will be determined by the temperature of the adjacent regions of the phase change material 130. Thus, in use, when most or all of the phase change material 130 has melted, the outer wall temperature 120 will reach its maximum value.

[0060] Once the outer wall 120 has reached the desired temperature, the hair styling device is ready to be charged and can thus be removed from the heat source. The hair styling device enters the styling phase, during which a portion of the user's hair is then wrapped around the outer surface 122.

[0061] The phase change material 130 continues to heat the outer surface 122 of the outer wall 120 during the styling phase through energy transfer, thereby styling the portion of the hair wrapped around it. As the outer surface 122 radiates this thermal energy to the hair, the outer surface 122 and subsequently the phase change material 130 will cool, and the phase change material 130 will begin to solidify. During the solidification process, the temperature of the phase change material 130 remains constant and it releases its latent heat energy, which continues to heat the outer surface 122. Once the phase change material 130 has solidified, it will again begin to cool, releasing energy in the form of sensible heat. The phase change material 130 will cool until it reaches equilibrium with the ambient temperature surrounding it.

[0062] In some examples, the hair styling devices 200, 300, 400, 500 include one or more members 240, 340, 440, 540 to assist in transferring heat to the phase change material. Figures 2 to 3d Various styling devices 200, 300, 400, 500 with different member arrangements are shown. It should be understood that any suitable member arrangement can be envisioned in accordance with the present invention, including but not limited to combinations of the described member arrangements. In other words, any member arrangement capable of distributing heat from the core to the phase change material can be envisioned. Any feature described with respect to one of these example devices should be considered applicable to any other example, unless it is inherently incompatible with it. For the sake of brevity, the features of the styling devices described here that are the same as those described above with reference to Figure 1a and 1b will not be repeated.

[0063] Now refer to Figure 2, an exemplary shaping device 200 incorporating member 240 is shown. Member 240 is located between core 210 and outer wall 220 such that it extends into a phase change material (not shown). There is a space (filled with phase change material) between edge 242 of member 240 and outer wall 220. Member 240 is formed of a material having a high thermal conductivity, which is aluminum in this example, and is welded to core 210 such that it is in contact with the core.

[0064] Member 240 is a continuous aluminum sheet that spirals around core 210 such that the edge opposite edge 242 is in contact with core 210, and edge 242 is adjacent to but spaced from outer wall 220. In this way, member 240 extends along the length of device 200. Member 240 effectively increases the heating surface area of core 210, such that the area of the phase change material in contact with a surface having a high thermal conductivity is increased.

[0065] Figure 3a An exemplary hair styling device 300 having an exemplary arrangement of multiple members 340 is shown, Figure 3b is shown Figure 3a in a plan view. Multiple members 340 project from and radiate outwardly from core 310 such that core 310 and members 340 have a toothed cross-section (as Figure 3b shown). Members 340 extend to outer wall 320. Multiple members 340 are fixed to core 310 and outer wall 320, for example by welding. Multiple members 340 extend along the length of hair styling device 300 parallel to the longitudinal axis 302 of core 310 and between upper wall 312 and lower wall 314.

[0066] In this example, hair styling device 300 has 12 planar members 340 that are equally spaced around core 310 (any suitable number can of course be contemplated). The length of multiple members 340 is 8.5 mm, and the length of hair styling device 300 is 9 mm (including the thickness of upper wall 312 and lower wall 314). Multiple members 340 have a thickness of 0.5 mm.

[0067] Phase change material 330 is located between core 310 and outer wall 320. Phase change material 330 is located between adjacent members 340 and is likewise divided into portions 330a-l by those members 340. Phase change material 330 is the same material, which is RT111HC in this case. In some other cases, one or more of portions 330a-l may each have a different phase change material.

[0068] Figure 3cAn example is shown in which the hair styling device 400 also has a plurality of members 440. In this example, each of the plurality of members has an extension that is partially curved from the core 410 toward the outer wall 420. Each member 440 has a first portion 446 that bifurcates from a second portion 448 at an end 442 of the member 440 adjacent to the outer wall 420. Of course, examples where the bifurcation is closer to the core 410 can be envisioned, such as an example that includes multiple bifurcated portions on one member 440.

[0069] Figure 3d Another example of a hair styling device 500 having eleven members 540 is shown. In this example, the plurality of members 540 are disk-shaped members.

[0070] The plane of each member 540 is perpendicular to the longitudinal axis 502 of the core 510. The plurality of members 540 project around the core 510 toward the outer wall 520. The plurality of members 540 extend approximately 80% of the distance between a point on the core 510 and a corresponding point on the outer wall 520 and have a length of 28 mm. Each of the plurality of members 540 is equally spaced along the length of the core 510.

[0071] Now looking Figures 4a to 4d , an example of Figure 3d the charging stage of the styling device 500 is shown. During this charging stage, the core 510 is heated using a heat source (not shown). Thermal energy from the core 510 is transferred along the members 540 to the phase change material 530. That is, both the core 510 and the members 540 transfer heat to the phase change material 530. The transfer of thermal energy is mainly by radiation from the core 510 and the members 540 into the phase change material 530. The thermal energy is then stored as sensible heat in the phase change material 530 until the phase change material reaches its melting temperature.

[0072] Once the melting temperature is reached, heating via the core 510 and the members 540 causes a phase change (melting) of the phase change material 530. The phase change material 530 melts over time, and the regions of the phase change material closest to the core 510 and the members 540 melt earlier than the regions further away from the core 510 and the members 540. The phase change material 530 thus has a melted portion 532 of the phase change material 530 (adjacent to the core 510 and the members 540) and another solid portion 534 of the phase change material 530 (adjacent to the outer wall 520). As shown, the melted portion 532 can be continuous around the core 510 and the members 540 or can be smaller sub-portions. The boundary 536 between the two portions 532, 534 is where the phase change material 530 undergoes a phase change. At the boundary 536, the phase change material 530 is a mixture of solid and liquid.

[0073] As Figures 4a to 4dAs shown in the process described, the area of the molten portion 532 of the phase change material 530 increases with time, causing the boundary 536 to move towards the outer wall 520. The molten portion 532 expands radially from the core 510 and the member 540 until most (if not all) of the phase change material 530 is melted. After the phase change material 530 has undergone a phase change, the temperature of the phase change material 530 can start to increase again, storing energy as sensible heat once more. Once the desired temperature of the phase change material 530 and thus the outer surface 522 has been reached, the heat source no longer heats the core 510. This occurs when at least 95% of the phase change material 530 has reached the molten state, and the hair styling device 500 can thus be used by the user to style hair, entering the styling phase.

[0074] The hair styling device 500 fully charges (i.e., reaches the desired temperature of the outer surface 522) in less than 20 minutes, such as 15 minutes.

[0075] During the charging phase and the styling phase, the thermal energy from the phase change material 530 is continuously transferred to the outer surface 522 of the outer wall 520. During the charging process, at least some of the thermal energy from the phase change material 530 is transferred to the outer surface 522 of the outer wall 520. Thus, during the charging phase, the temperature of the outer surface 522 also increases. During the styling phase, the temperature of the phase change material 530 drops, releasing thermal energy as sensible heat energy, and the outer surface 522 releases this thermal energy to the hair. Once the phase change material 530 reaches the solidification temperature, the phase change material 530 starts to undergo a phase change and maintains a substantially constant temperature. This solidification releases thermal energy as sensible heat energy and can keep the outer surface 522 at a constant temperature. Once the phase change material 530 has solidified, it continues to cool, releasing more thermal energy as sensible heat energy until it reaches room temperature. Throughout the styling process, the phase change material 530 transfers energy to the outer wall 520, so that the outer surface 522 provides the thermal effect required for styling hair.

[0076] As Figure 5a and 5b shown, in order to charge the hair styling device, a base 650 is used. The base 650 has a plurality of cavities 652a - c from which heat sources 660a - c protrude. The heat sources 660a - c are coupled to electrical connections 654.

[0077] Each cavity 652a - c is shaped to respectively accommodate a corresponding hair styling device 600a - c (as Figure 5bAs shown). The shape of each cavity 652a-c corresponds to the shape of the respective hair styling device 600a-c. The cavity has a tolerance of 0.5 mm to 2 mm such that the respective hair styling devices 600a-c fit relatively tightly therein, such that there is little air gap between the outer surface 622 of the respective hair styling devices 600a-c and the walls of the cavities 652a-c. In some cases, the cavity has a heat-insulating wall (not shown).

[0078] The cavities 652a-c within the base 650 can be oriented such that each respective hair styling device 600a-c is energized in an upright position relative to the base 650. That is, the upper and lower walls 612, 614 extending between the outer surface 622 of the core (not shown) and the outer wall (not shown) are parallel to the base 656 of the base 650. In use, the base 650's base is typically placed on a surface. In this way, gravity can act parallel to the longitudinal axis of the hair styling devices 600a-c.

[0079] The heat sources 600a-c project from the bases of the respective cavities 652a-c such that the heat sources 600a-c fit within the cores of the respective hair styling devices 600a-c placed within the cavities 652a-c. During energization, the heat sources 600a-c are in contact with the cores of the hair styling devices 600a-c. The heat sources 600a-c are electrically driven resistive heaters.

[0080] The base 650 further includes an electrical connection 654, such as a plug or a battery. The electrical connection 654 is electrically coupled to each of the heat sources 660a-c in order to provide an electrical connection to heat the heat sources 660a-c.

[0081] The base 650 includes controllers 658a-c associated with each of the heat sources 660a-c. The controllers 658a-c are PID controllers which can, for example, start and stop the heat sources 660a-c by controlling the electrical connection. Once the desired temperature of the phase change material or the outer surface 622 of one of the hair styling devices 600a is achieved, the corresponding heat source 660a is turned off. The base 650 includes a temperature sensing device (not shown) within the cavity 652a which is coupled to the controller 658a.

[0082] In some examples, the controller can be a single controller which turns on and off some or all of the heat sources 660a-c in one action. In other examples, the base 650 can have switch and timer means for controlling the heating of the heat sources 660a-c.

[0083] As Figure 5bAs shown, a portion 604a-c of the hair styling devices 600a-c protrudes from their respective cavities 652a-c. The portions 604a-c may allow a user to grasp the hair styling devices 600a-c to remove them from the base 650. Thus, the portions 604a-c may be additional portions at the top of the device as described with reference to the previous figures. This portion is a heat-insulating cap or the like.

[0084] The base and one or more hair styling devices together provide a hair styling kit. The kit includes hair styling devices of various sizes for styling different portions of the user's hair. Although illustrated as three hair styling devices, the kit may include any suitable number. The kit may also include optional features such as heat-protective gloves and / or clips to assist in securing each styling device in place on the user's head.

[0085] The above examples should be understood as illustrative examples of the present invention. Further embodiments of the present invention may be contemplated. For example, although the above description refers to the hair styling device (at least the core and the outer surface) as tubular, any suitable shape may be used, such as frustoconical. Those skilled in the art will understand that variations in the outer surface and / or the shape of the device will generally have a direct impact on the wave or curve style within the user's hair. In these examples, the core may be the shape corresponding to the entire device, i.e., thus the ratio of the phase change material to the core remains substantially constant. Additionally, the cavities on the charging base may be complementary shapes to closely fit each styling device.

[0086] The heat source was described above as forming part of the base, however in some examples, the heat source may be part of the hair styling device, such as a resistive heater disposed inside and thermally coupled to the core. In these cases, the base may provide an electrical connection to allow the heat source to provide heat through resistive heating.

[0087] It should be understood that any feature described with respect to any one embodiment may be used alone, or in combination with the other features described, and may also be used in combination with one or more features of any other embodiment, or with any combination of any other embodiments. Additionally, equivalents and modifications not described above may also be employed without departing from the scope of the present invention as defined by the appended claims.

Claims

1. A hair styling device, comprising: A core having a high thermal conductivity; An outer wall spaced apart from the core, the outer wall including an outer surface around which a portion of the user's hair can be wrapped; And A phase change material disposed between the core and the outer wall, the phase change material configured to release heat to the portion of the user's hair via the outer surface during use.

2. The hair styling device according to claim 1, wherein, The hair styling device further includes a member for transferring heat from the core to the phase change material, the member being located between the core and the outer wall.

3. The hair styling device according to claim 2, wherein, The member extends from the core towards the outer wall.

4. The hair styling device according to claim 3, wherein, The member extends from the core by more than half of the distance from a first point on the core to a second point on the outer wall that is directly opposite the first point.

5. The hair styling device according to any one of claims 2 to 4, wherein, The member includes a first portion and a second portion, wherein the first portion and the second portion are separated from each other.

6. The hair styling device according to any one of claims 2 to 5, wherein, The member includes a plurality of holes.

7. The hair styling device according to any one of the preceding claims, wherein, The hair styling device includes a plurality of members distributed around the core, the plurality of members configured to transfer heat from the core to the phase change material.

8. The hair styling device according to claim 7, wherein, Each of the plurality of members has a length corresponding to the length of the core, and the lengths of the plurality of members extend parallel to the longitudinal axis of the core.

9. The hair styling device according to claim 7, wherein, Each of the plurality of members includes a disk, and each disk is spaced apart from an adjacent disk along the length of the core.

10. The hair styling device according to any one of claims 7 to 9, wherein, The plurality of members are uniformly distributed around the core.

11. The hair styling device according to any one of claims 7 to 10, wherein, At least one of the plurality of members extends from the core to the outer wall.

12. The hair styling device according to any one of claims 7 to 11, wherein, Each of the plurality of members is the same.

13. The hair styling device according to any one of the preceding claims, wherein, The phase change material has a melting temperature of at least 50 °C.

14. The hair styling device according to any one of the preceding claims, wherein, The phase change material has a latent heat of at least 150 kJ / kg.

15. The hair styling device according to any one of the preceding claims, wherein, The phase change material is an organic material.

16. The hair styling device according to any one of the preceding claims, wherein, The outer wall has a lower thermal conductivity than the core.

17. The hair styling device according to any one of the preceding claims, wherein, The hair styling device further includes a heat source thermally coupled to the core.

18. A hair styling kit, comprising: The hair styling device according to any one of claims 1 to 18; And A base, the hair styling device being configured to be removably coupled to the base, wherein the base is configured to heat the core of the hair styling device via the heat source when the hair styling device is coupled to the base.

19. The hair styling kit according to claim 18, wherein, The base includes at least one cavity configured to receive at least one hair styling device therein.

20. The hair styling kit according to claim 19, wherein, The cavity includes a heat insulating wall such that when the hair styling device is coupled to the base, the cavity insulates the hair styling device.

21. The hair styling kit according to any one of claims 20 to 20, wherein, The base is configured to receive at least one hair styling device in an upright position relative to the base.

22. The hair styling kit according to any one of claims 18 to 21, wherein, The base includes a controller configured to maintain the heat source at an optimal temperature for melting the phase change material.

23. The hair styling kit according to any one of claims 18 to 22, wherein, The hair styling kit includes a plurality of hair styling devices.

24. The hair styling kit of claim 23 when dependent on claim 19, wherein, The base includes a plurality of cavities corresponding to the plurality of hair styling devices.

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