Field of the Invention

The present invention relates to apparatus for treating hair, and in particular, although not exclusively, to apparatus for hair styling.

Background to the Invention

Within the prior art there are many examples of tools used in the manipulation and styling of hair. Specific examples include hand held curling tongs and hair straighteners that enable a user to style hair in the desired way. As heated hair is more easily styled than non heated hair prior art hair styling tools commonly include at least one heating element configured to provide a heating effect, via at least one heated surface, to the hair during styling.

For example, when styling hair using a hair straightening tool, a user sandwiches a portion of hair between two opposed heating surfaces. A number of different materials have been proposed for the heating surfaces including steel, ceramic or glass, these materials being heated by at least one heating element or source. The opposed heating surfaces are slowly drawn across the hair providing a hair straightening effect.

A common problem with metallic, ceramic and glass material heating surfaces is the inherent surface roughness and the presence of surface imperfections. When hair is drawn across a rough surface there is a strong tendency for the hair to snag causing the hair to break. In an attempt to address this problem, conventional heating surfaces require extensive polishing. Conventional polishing processes are both time intensive and costly.

A further problem with the use of ceramic heating materials manufactured from clay precursors is the presence of particulate, impurities. These granular impurities both increase the surface roughness and reduce the heat transfer effectiveness of the ceramic material.

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A further disadvantage with ceramic and glass heating materials is their inherent brittle mechanical properties. This brittleness is disadvantageous for two reasons. Firstly, the glass or ceramic material typically requires shaping before being polished. The brittleness of these materials makes it difficult to shape the plates particularly where rounded edges are desired. Splintering or fracturing of the material, during the manufacturing process, is often encountered. Secondly, the temperature of the heating plates of the hair styling appliances, during normal operative conditions, typically reaches in excess of 200 ⁰ C. When operating at these elevated temperatures, if the heating materials are exposed to water or any other significantly cooler medium they will crack and break.

What is required therefore, is a hair styling appliance comprising a heating material without the disadvantages associated with the prior art devices.

Summary of the Invention

Accordingly, the inventors provide a hair styling device comprising ceramic heating plates configured with enhanced surface glossiness over ceramic, glass and steel materials known in the art and used with hair styling tools. Through a multi stage grinding and polishing process, the surface glossiness of both a substantially planar working surface and additional curved surfaces of the ceramic plates is achieved.

According to a first aspect of the present invention there is provided a hair styling device comprising: a first handle and a second handle, said second handle moveably connected to said first handle; a first heating plate mounted at said first handle and a second heating plate mounted at said second handle, said first heating plate positioned substantially opposed to said first heating plate; means to heat said first and second heating plates; said device characterised in that: said first and second heating plates are aluminium oxide ceramic plates, each plate comprising a substantially planar working surface bordered by a plurality of curved edge regions.

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Each ceramic plate comprises at least one substantially planar surface configured for positioning in contact with the hair. In use, the two handles may be brought together to sandwich the hair between the exposed, highly glossed surface(s) of each ceramic plate.

Preferably, the planar working surface and curved edge regions of each aluminium oxide ceramic plate is highly polished.

Preferably, a thermally insulating material is positioned between each heating plate and each handle.

Preferably, the first and second handles are connected towards one end of each handle, the handles being optionally, hingably connected together. In particular, the first heating plate may be positioned in a first half of the first handle and the second heating plate may be positioned in a first half of the second handle, the first and second handles being connected together in a second half of each handle.

Optionally, grip means may be provided at either of the first or second handles, the grip means being positioned in the first half of each handle. Profiling may be provided on the grip means such that the device may be grasped and/or manipulated by the fingers of a user via the grip means. The grip means may be formed integrally or non-integrally with each of the handles and may preferably be manufactured from natural or synthetic rubber.

To removably secure each plate to each handle, a rail may be provided extending from a surface of each plate opposed to the planar working surface. The rail is configured to mate with a lip or similar groove means formed at each of the first and second handles.

The substantially planar surface of the ceramic plate is bordered by rounded edges such that no sharp edges are exposed to the hair during styling.

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Both the substantially planar surface and the rounded edges of the ceramic plate may comprises an equal surface glossiness or surface mirroring being greater than conventional glass, ceramic or steel heating plates used within known hair styling appliances.

According to a second aspect of the present invention there is provided a method of manufacturing a ceramic plate for a hair styling device comprising a first handle, a second handle, a first heating plate secured to said first handle, a second heating plate secured to said second handle and means to heat said first and second heating plates, said method comprising: mixing powdered aluminium oxide with wax to form a paste; introducing said paste into a mould; heat treating said paste at a temperature greater than 1000 ⁰ C to produce said ceramic plate; and polishing at least one surface of said ceramic plate.

Preferably, the ceramic plate is a micro crystal ceramic in that the particulate size of the finely powdered aluminium oxide is within the range 25 to 45 μm. Alternatively, the particulate size of the powdered aluminium may be within the range 1 to 10 μm and preferably 3 to 4 μm.

Due to the use of finely powdered aluminium oxide sintering occurs at the grain boundaries resulting in a micro crystal structure containing a relatively low number of closed pores. Moreover, the pores within the micro structure are of reduced size owing to the use of the finely powered aluminium oxide. The minimising of the multiplicity and size of closed pores within the ceramic micro structure allows a smoother surface to be produced following grinding and polishing.

Preferably, the paste and mould is heat treated for between 24 to 36 hours or between 12 to 18 hours.

The paste and mould may be heated at a temperature within the range 1500 to 1700 ⁰ C or alternatively within the range 1640 to 175O ⁰ C.

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Preferably, a de-waxing step is included during manufacture of the ceramic plates possibly with the use of at least one de-waxing powder and optional, additional heat styling up to 1100 to 1500 ⁰ C for a number of hours.

The resulting aluminium oxide ceramic plates are then cleaned, optionally involving washing with one or more liquids, in particular water, and at least one degreasing agent.

The planar and rounded edges of the ceramic plates are then smoothed via a multi stage grinding/polishing process. The process may comprise a grinding and polishing of the planar surface and rounded edges manually or an automated grinding and polishing process may be employed. In particular, grinding wheels or stones may be used for the initial stages of the smoothing process. Following the initial grinding steps the ceramic plates are polished via a multi step process involving sequential use of finer abrasive polishing solutions as are known in the art, including for example alumina or silicon carbide.

Preferably the step of polishing each surface and/or region of the ceramic plates comprises the following steps:

• polishing said surface and said curved regions with a first grade abrasive;

• polishing said surface and said curved regions with a second grade abrasive, said second grade abrasive being more abrasive than said first grade abrasive;

• polishing said surface and said curved regions with a third grade abrasive, said third grade abrasive being more abrasive than said second grade abrasive; • polishing said surface and said curved regions with a fourth grade abrasive, said fourth grade abrasive being more abrasive than said third grade abrasive.

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Brief Description of the Drawings

For a better understanding of the invention and to show how the same may be carried into effect, there will now be described by way of example only, specific embodiments, methods and processes according to the present invention with reference to the accompanying drawings in which:

Fig 1 herein illustrates a side elevation view of a hair styling device according to a specific implementation of the present invention;

Fig 2A herein illustrates a plan view of the hair styling device of fig 1 herein.

Fig 2B herein illustrates an underside view of the hair styling device of fig 1 herein;

Fig 3 herein illustrates a perspective view of the hair styling device of fig 1 herein;

Fig 4 herein illustrates a front elevation view of the hair styling device of fig 1 herein;

Fig 5 herein illustrates a rear elevation view of the hair styling device of fig 1 herein;

Fig 6 herein illustrates a cross sectional elevation view of one of the elongate moveable handles comprising the ceramic heating plate;

Fig 7 herein illustrates a perspective view of a ceramic plate utilised with the present invention.

Detailed Description

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There will now be described by way of example a specific mode contemplated by the inventors. In the following description numerous specific details are set forth in order to provide a thorough understanding. It will be apparent however, to one skilled in the art, that the present invention may be practiced without limitation to these specific details. In other instances, well known methods and structures have not been described in detail so as not to unnecessarily obscure the description.

Figure 1 herein illustrates a side elevation view of the hair styling apparatus according to the specific implementation of the present invention. The device comprises a first handle 100 and a second handle 101 , the handles being moveably connected to one another by hinge connection 104. Handle 100 comprises a free end 110 positioned opposed to a free end 111 of second handle

101. A first ceramic plate 102 is positioned towards free end 110 of handle 100 with a second ceramic plate 103 being positioned towards free end 111 of handle

101. Ceramic plates 102, 103 are positioned opposed and in contact with one another, or nearly touching, via substantially planar surfaces 112, 113, respectively.

First ceramic plate 102 is mounted at handle 100 via suitable mount means

109. Similarly, the second ceramic plate 103 is mounted at handle 101 by suitable mount means 108. Means 108, 109 may comprise a suitable thermally insulating material configured to impede or prevent heat transfer between ceramic plates 102, 103 and handles 100, 101.

Control means 106 are provided to enable a user to control the operative conditions of the hair styling device.

Conventional electrical cabling 105 is provided as means for connecting the hair styling device to a suitable power source, for example the mains electricity supply.

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Figures 2A and 2B herein illustrate respectively, a plan view and underside view of the hair styling device of figure 1 herein.

Figure 3 herein illustrates a perspective view of the hair styling device of figure 1 herein, and figures 4 and 5 herein illustrate respectively, front and rear elevations, of the hair styling device of figure 1 herein.

Handles 100, 101 are configured to more via hinge point 104 which may include any suitable connection means including for example a pivot pin or hinge being freely movable or optionally mechanically biased using suitable spring means. Accordingly, ceramic plates 102, 103 may be brought together as illustrated in figure 1 herein, or may be separated from one another as the handle ends 110 and 111 are spaced apart by a user gripping one or both handles so as to draw handle end 110 away from handle end 111. Ceramic plate 102 comprises a first substantially planar surface 112 positioned opposed to a substantially planar surface 113 of ceramic plate 103. In use, ceramic surfaces 112, 113 are configured to transfer heat from a heating element or heat source (not shown) to the hair sandwiched between the plates 102, 103.

Handle ends 110, 111 may comprise gripping portion 203 configured to allow a user to grip handles 100, 101 towards the free ends 110, 111. Region 203 may comprise profiling and may be formed integrally or non-integrally with the handle.

Means 107 is provided to space apart handles 100, 101, when the handles are brought to their closed position as illustrated in figure 1 herein, whereby surfaces 112 and 113 are in contact or are nearly touching.

Control means 106 may comprise separate control buttons 200, 201 , 202 being operable by a user to control the functionality of the device including for example, turning the device on or off, and controlling the magnitude of the heating effect supplied via surfaces 112, 113. Control means 106 may further

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comprise display means or suitable illumination means so as to indicate to a user that the device has reached the required operating temperature and is ready for use.

Ceramic plate 102 comprises at least two curved regions or surfaces 301 located either side of the substantially planar heating surface 112. Similarly, ceramic plate 103 comprises at least two curved regions or surfaces 300 positioned at two sides of the heating surface 113. These outmost positioned exterior curved edges 300, 301 which are also heated, prevent the hair from being snagged or gripped by the ceramic plates when sandwiched and drawn between heating surfaces 112, 113, such snagging resulting in breakage of individual hair strands.

Ceramic plates 102, 103 according to the specific implementation of the present invention are micro crystal aluminum oxide. Alternative materials usable with the present invention include silicon nitride, silicon carbide, zirconia or aluminum nitride. Alternatively, the combination of any one of these materials may be utilised with the present invention.

According to the specific implementation of the present invention, each aluminum oxide ceramic plate is prepared according to the following processing steps:

• A very fine grade power of aluminum oxide is mixed with wax. • The aluminum oxide wax composition is heated and stirred to form a paste.

• The paste is injected into a mould and pressurised to form a highly compacted cake or greenstate ceramic.

• The cake, within the mould is sintered within an oven in the temperature range 1640 to 175O ⁰ C for 24 to 36 hours, depending upon the desired thickness and size of the ceramic plates.

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• De-waxing of the ceramic plates occurs by heating the plates up to 1100 ⁰ C for up to 4 hours. Optionally, a de-waxing powder may be used.

• The ceramic plates are cleaned using detergents or de-greasing agents.

• The ceramic plates are then finally ground and polished via a series of grinding and polishing steps using grinding wheels, stones and/or abrasive polishing solutions as are known in the art, including for example alumina or silicon carbide based formulations.

The ceramic plates manufactured according to the processing steps of the present invention comprise operative heating surfaces of a high surface glossiness being devoid of macroscopic and microscopic surfacing imperfections including cavities or projections. Importantly this high surface glossiness is a characteristic of both the planar and outer curved surfaces.

Figure 6 herein illustrates a cross-sectional end elevation view of ceramic plate 103 mounted at handle 101. According to the hair styling device of Figure 1 herein. Heating material 103 comprises a substantially planar surface 600, being the operative or working surface configured for positioning in contact with the hair. The planar surface 600 is bordered along two of its edges by curved surfaces 601 whereby when ceramic plate 103 is secured in position at the handle there are no external sharp edges exposed to the hair. Moreover, the shape of the exposed, external surface of the ceramic plate is configured to match that of the handle and/or mount 108, 109 at the junction between the handle and the ceramic. In order to prevent heat transfer between the ceramic and the handle, suitable insulating means is provided at this junction between the ceramic and the handle (region 602).

At least one interior surface 604, 606 of the ceramic plate is configured for positioning in contact with a heating element 603 configured to generate a heating effect at surface 604, positioned adjacent substantially planar external surface 600. A suitable insulating material or a suitable air gap may be

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2006/000063

-11- positioned between heating element 603 and an interior surface 605 of handle 101.

Heating element 603 may comprise any known, conventional heating element being for example, a metalic or ceramic material. The heating element may be bonded to be ceramic heating plate by a thermally conductive adhesive. Alternatively the heating element may be secured in contact with the ceramic plate by any other conventional mechanical securing means. Additionally, means may be provided to dissipate the heat from heating element 603 to the interior surface 604, 606 of the ceramic plate.

In particular, the present invention comprises a ceramic heater 603 being a semi-conductive ceramic with an electrical resistance that varies with temperature. Additionally the insulating material 108, 109 positioned between the heating element and the ceramic plate and/or the handle comprises a high grade polymer material being a thermal insulator.

Figure 7 herein illustrates a perspective view of one of the ceramic plates of Figure 1 herein comprising a substantially planar surface 600 bordered by at least two curved surfaces 601. To assist with securing of the ceramic plate 103 to the handle 101, rails are provided 700 formed at the interior surface of the plate whereby rails 700 are not exposed when the ceramic plate is secured to the handle during normal use. Lips (not shown) may be formed on each handle 100, 101 configured to mate with rails 700.

When heated, the fine grain micro crystal ceramic material of the present invention is configured to emit far infrared rays. This is a particularly advantageous property of the ceramic plates according to the present invention as it is known that far infrared rays are beneficial to the human body and in particular human hair. The far infrared rays emitted by ceramic plates 102, 103 via surfaces 600 and curved surfaces 601 ionize and activate water molecules in

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the hair in addition to improving oxygen levels and helping to eliminate chemicals and toxins.

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