Hair styling apparatus

Abstract

A hair styling apparatus including a first and a second arm moveable between a closed position in which a contacting surface of the first arm is adjacent a contacting surface of the second arm and an open position in which the contacting surfaces of each arm are spaced apart, whereby the contacting surfaces of each arm have complementary profiles so that, in use, a section of hair is clamped between the contacting surfaces when the arms are in the closed position, and where a heating zone on at least one of the contacting surfaces is provided to heat the section of hair between the contacting surfaces, a cooling zone on at least one of the contacting surfaces is provided for cooling the section of hair after the section of hair has been heated, and the cooling zone is curved whereby, in use, as the hair styling apparatus is moved along the section of hair in a generally linear fashion, the section of hair is curled.

Claims

1. A hair styling apparatus comprising a first arm and a second arm, the first and second arms being elongate in length such that each of the first and second arms has a longitudinal axis along its length and being coupled together at one end thereof to allow the first and second arms to be moveable between a closed position in which a first hair contacting surface of the first arm is adjacent a second hair contacting surface of the second arm and an open position in which the first and second hair contacting surfaces are spaced apart; wherein the first and second hair contacting surfaces have complementary profiles so that, in use, a section of hair is clamped between the first and second hair contacting surfaces when the first and second arms are in the closed position; wherein the first arm comprises a first heatable plate and a first heater for heating the first heatable plate, wherein an outer surface of the first heatable plate forms a first part of said first hair contacting surface; wherein the second arm comprises a second heatable plate and a second heater for heating the second heatable plate, wherein an outer surface of the second heatable plate forms a first part of said second hair contacting surface; wherein the first heatable plate is positioned on the first arm and the second heatable plate is positioned on the second arm so that the first and second heatable plates are adjacent each other when the first and second arms are in the closed position for heating the section of hair; wherein the first arm further comprises first and second cooling members for cooling the section of hair, the first cooling member having a surface that forms a second part of said first hair contacting surface and the second cooling member having a surface that forms a third part of said first hair contacting surface, the first and second cooling members being positioned on the first arm so that the first part of said first hair contacting surface is positioned between the second and third parts of the first hair contacting surface in a direction transverse to the longitudinal axis of the first arm; and wherein the first arm further comprises a heat bridge that extends within the first arm behind the first heater and between the first and second cooling members, and that is formed of a material that is arranged to allow heat gained by the first cooling member to be transferred through the heat bridge to the second cooling member.

2. A hair styling apparatus as claimed in claim 1, wherein at least one of the second and third parts of the first hair contacting surface is curved whereby, in use, as the hair styling apparatus is moved along the section of hair in a generally linear fashion, the section of hair is curled.

3. A hair styling apparatus as claimed in claim 1, wherein at least one of the second and third parts of the first hair contacting surface is planar.

4. A hair styling apparatus according to claim 1, wherein the second arm comprises third and fourth cooling members, wherein the first cooling member is positioned on the first arm and the third cooling member is positioned on the second arm so that the first and third cooling members are adjacent each other when the first and second arms are in the closed position and wherein the second cooling member is positioned on the first arm and the fourth cooling member is positioned on the second arm so that the second and fourth cooling members are adjacent each other when the first and second arms are in the closed position.

5. A hair styling apparatus according to claim 4, wherein at least one of the first, second, third and fourth cooling members further comprises a guide member positioned to guide the cooled section of hair into a curl.

6. A hair styling apparatus according to claim 5, wherein said first cooling member comprises a first guide member and said third cooling member comprises a second guide member, and wherein the first guide member has a convex surface and the second guide member has a complementary concave surface.

7. A hair styling apparatus according to claim 1, wherein the heat bridge comprises a conductive plate or rod.

8. A hair styling apparatus according to claim 1, wherein the heat bridge comprises a heat pipe.

9. A hair styling apparatus according to claim 1, wherein said heat bridge comprises one or more cooling fins.

10. A hair styling apparatus according to claim 1, wherein the first part of said first hair contacting surface and the first part of said second hair contacting surfaces are planar and the second part of the first hair contacting surface is convex and the second hair contacting surface has a complimentary concave shape at a position corresponding to the second part of the first hair contacting surface.

11. A hair styling apparatus according to claim 10, wherein the convex second part of the first hair contacting surface has a radius of between 2 mm and 10 mm.

12. A hair styling apparatus according to claim 1, wherein the first part of the first hair contacting surface is curved.

13. A hair styling apparatus according to claim 1, wherein one or both of the first and second cooling members extend along at least part of the longitudinal axis of the first arm.

14. A hair styling apparatus according to claim 1, wherein the first and second cooling members are conductive.

15. A hair styling apparatus according to claim 1, wherein the first and second hair contacting surfaces are supported on a resilient suspension to allow movement between the first hair contacting surface and the first arm and to allow movement between the second hair contacting surface and the second arm.

16. A hair styling apparatus according to claim 1, wherein the first heatable plate extends along at least part of the length of the longitudinal axis of the first arm and the second heatable plate extends along at least part of the length of the longitudinal axis of the second arm.

17. A hair styling apparatus according to claim 1, wherein the first and second heatable plates are configured to heat the hair to above 160° C.

18. A hair styling apparatus according to claim 17, wherein the first or second cooling member is configured to bring the hair temperature to between 90° C. and 160° C. after the hair has been heated by the first and second heatable plates.

19. A hair styling apparatus according to claim 1, further comprising a thermal insulator between the first heater and the first cooling member and a thermal insulator between the first heater and the second cooling member.

Description

BRIEF DESCRIPTION OF DRAWINGS

(1) For a better understanding of the invention and to show how it may be carried into effect reference shall now be made, by way of example only, to the accompanying drawings in which:

(2) FIG. 1 shows a perspective view of a hair styling apparatus;

(3) FIG. 2a shows a schematic cross-section through the line A-A in FIG. 1 showing planar heating and cooling sections;

(4) FIG. 2b illustrates the cross-section of FIG. 2a showing the way in which the device can be used to curl hair;

(5) FIG. 3a is a plan view of an arm of the device of FIG. 1;

(6) FIG. 3b is a plan view of an arm from any one of the devices of FIGS. 5 to 8;

(7) FIG. 4 shows a perspective view of a further alternative hair styling apparatus;

(8) FIG. 5 shows a schematic cross-section through the line A″-A″ in FIG. 4 showing a planar heating section and a curved cooling section;

(9) FIG. 6 shows a variant of the cross-section shown in FIG. 5;

(10) FIG. 7 shows a variant of the cooling means through one arm of the device of FIG. 4;

(11) FIG. 8 shows a further variant of the cooling means through one arm of the device of FIG. 4;

(12) FIG. 9 is a schematic illustration of one of the apparatus angled adjacent a user's head;

(13) FIG. 10 shows a further variation of the device for straightening and curling hair; and

(14) FIG. 11 shows a further variation of the device used for straightening hair.

DETAILED DESCRIPTION OF DRAWINGS

(15) As the skilled person will appreciate, during styling, hair is under tension between the user's head and the styling apparatus. A curl forms in the hair as the styling apparatus is released from the hair. In many of the Figures styled hair is shown exiting the styling apparatus curled—this is purely for illustrative purposes to shown the effect on the hair once it has moved through the styling apparatus. Curls are formed when the hair is no longer under tension.

(16) FIG. 1 shows a hair styling apparatus comprising an elongate body 30 which forms a handle for a user to grip the apparatus. A pair of arms 32 are attached to the body. The arms are hinged together at one end where they are attached to the body. The arms are moveable between a closed position in which the opposed ends of the arms are adjacent each other and an open position in which the opposed ends of the arms are spaced apart. A heating zone and a cooling zone are formed on each arm as described in more detail with reference to FIGS. 2a and 2b.

(17) The body houses the components necessary for the operation of the heating and cooling zones. Thus, the body houses a heating system and a cooling system together with a user operated control mechanism for switching the apparatus on and off.

(18) In many of the arrangements, the cooling system may use fluid, e.g. air. This may be delivered by a motor and fan which are housed in the body with conduits through the body and arms to deliver the fluid to the cooling zone. The fan types include axial, radial or centrifugal. Alternatively, the fluid may be delivered by a gas micro pump driven by a motor with the pump and motor housed in the body with conduits through the body and arms to deliver the fluid to the cooling zone. The pump types included diagram pump, gear pump, scroll pump or sliding vain scroll pump. The fluid may be delivered at high pressure to ensure that it cools all the hair. This type of cooling system may be used in any of the arrangements show that use active cooling.

(19) One example of delivering high pressure air is an air blade. This provides a faster rate, more compact and more precise delivery. The micro air blades which deliver the air are integrated into the arms adjacent the heater plates. The micro scroll pump would be housed into the handle. The cooling air would be channelled along small flexible tubes to the micro air blades.

(20) An alternative more conventional technology is a “BLDC fan” which comprises a brushless DC motor and fan. This also delivers good results in a lower risk development.

(21) The rate of cooling the hair with atmospheric air is dependent on airflow volume and the pressure to deliver it, e.g. the higher the pressure, the greater the cooling in a smaller space (cooling zone). Increasing the back pressure is the most effective way to deliver greater volumes of air. Additionally the greater the air pressure the more effectively the air will pass through the hair enclosed by the apparatus which delivers more even cooling through the hair (this is key to reducing “frizz” and “fly aways”).

(22) Air flow regulation to the cooling zone will enable the user to vary curl size (diameter). Generally speaking, the more air, the better the hair will retain the curl and hence the curlier the hair. The air flow may be regulated by the user to control the rate of use through the hair. Such regulation may be done by valves controlled.

(23) For ambidextrous apparatus (which have two cooling curved surfaces), air flow regulation might be required to redirect airflow to the required surface. This is because the volume of air will be limited within the geometry of a hand held device. Such regulation might also provide a more cost effective, quieter, energy efficient system.

(24) The cooling system may use a combination of fluid and direct conduction. In such a system, the cooling zone in the arm may be one or more surfaces having a mass. In one arrangement, the fluid (e.g. air) may be used to cool the conductive surface in-between use i.e. between strokes. Such a system may further comprise a phase change material in the cooling zone. Residual heat is built up within the phase change material (latent heat) and can be dissipated between use or strokes, e.g. by using air. Suitable phase change materials include wax and/or water.

(25) Air flow regulation may be used to control the air flow to remove heat built up in conductive (working) surfaces of the product. This may increase the efficiency of styling (curling) or reduce surface temperatures to aid user ergonomics. The system could be implemented by sensing temperature rise or a greater temperature difference between the two cooling zone conductive plates. The air flow regulation may direct air to the hotter side(s) to reduce the temperature. As above, the methods of air flow regulation may include valves.

(26) Alternatively, the cooling system may be delivered by direct conduction. In such a system, the cooling zone in the arm may be one or more surfaces having a mass. The surface(s) have sufficient surface area to dissipate the heat built up to the environment in-between uses/strokes. Such an arrangement is discussed below with reference to FIG. 5.

(27) In any of the arrangements, the heating system may comprise a heater 35 which is mounted in the body and which is arranged in thermal contact with a pair of heatable plates 34. The heatable plates are substantially flat and are arranged on the inside surfaces of the arms in an opposing formation.

(28) In each arrangement, the cooling system is configured to provide rapid cooling of the hair on a curling surface as the hair exits from the heating zone. The curling surface may have a tight radius to enhance curling. Furthermore, it is critical to thermally insulate between the heating zone and the cooling zone. Thermally insulated materials and air boundaries can be used to insulate effectively.

(29) FIGS. 2a and 2b show a cross-section through the arms of the hair styling apparatus of FIG. 1 when the arms are in the closed position. The arms are moveable to the open position in the direction of arrows D. Similar arrows have been used throughout the figures to represent the direction of movement of the arms towards the open position. The heating zone 16 comprises a pair of heating plates, one in each arm, and a cooling zone 14 adjacent the heating zone.

(30) FIG. 2a shows the device being used as a hair straightener. During the straightening process, the hair 10 is clamped between the hot heatable plates. The apparatus is moved relative to the hair in the direction of arrow B. Similar arrows have been used throughout the figures. Whilst there is relative movement, the hair is kept under tension through the plates so as to mould it into a straightened form. As the hair passes through the heating zone, this prepares the hair for styling. The hair then passes through the cooling zone to set the style, in this case in straightened form. Thus, the hair reduces in temperature immediately after exiting the heaters.

(31) FIG. 2b shows the device of FIG. 2a being used to curl hair by rotating the hair straightener 180° towards the head prior to pulling the hair 10 through the hot heatable plates in the direction of arrow C. Similar arrows have been used throughout the figures. As with FIG. 2a, the hair is heated in the heating zone 16. The curl is made by using the curved outer surface of the device. Whilst on this surface, the hair reduces in temperature immediately after exiting from the heaters. The cooling is essential to ensure that the hair retains the shape of the curling surface. The cooling is enhanced by having a cooling zone 14 to cool the curling surface.

(32) The apparatus is simple to use. The pair of arms are opened and a lock of hair placed between the arms which are then closed. The apparatus is then pulled across the hair to create a curl in a similar manner to that in which a hair straightener straightens hair. The motion is linear. There is no twisting of the hair around the apparatus nor of twisting the apparatus relative to the head.

(33) FIGS. 5 to 8 illustrate various arrangements of the heating and cooling zones to provide an apparatus which curls hair easily. In each case, the heating and cooling zones are housed within one or both of the arms and the outer surface of the housing 20. The arms are shown in the closed position with the hair 10 sandwiched between the two arms. In the arrangements shown in FIGS. 2a and 2b, the contacting surfaces of the two arms are planar. However, the contacting surfaces to the two arms may be planar in the heating zone but non-planar (i.e. curved) in the cooling zone. The heating zone may also be non-planar. The most effective use of the cooling to create the curl is when the hair is at its hottest point, i.e. when it exits the heater and where the hair is at its tightest radius.

(34) The contacting surfaces of each arm have complementary shapes to ensure that the hair is in contact with both surfaces through both the heating and cooling zones. In other words, the contacting surfaces are generally parallel to each whether regardless of whether they are curved or planar. It is important to ensure that the two surfaces meet together uniformly to provide efficient heat transfer/cooling to the hair. The contacting surfaces may be supported on a resilient suspension in any of the arrangements described, e.g. elastomer supports, to allow some movement of each contacting surface relative to its arm, whereby an even finer tolerance is absorbed. This improves the good surface contact to the hair.

(35) In FIG. 5, one arm has a contacting surface having a generally planar section for the heating zone 16 and a convex section 15a for the cooling zone 14. The other arm also has a generally planar section for the heating zone but has a concave section 15b for the cooling zone. The curvature of the concave section 15b matches that of the convex section 15a so that both arms fit together snugly. The planar sections are generally at right angles to the direction D of opening and closing the arms.

(36) Dependant on the cooling method (and the rate at which it cools the hair) differing geometry can be used. For example, the angle at which the heating zone enters the cooling zone can be changed to increase the surface area of the hair in the cooling phase of the system. This can create a longer curved path for the hair to pass around in the cooling zone. The contacting surfaces each have both complementary convex and concave surfaces 15a, 15b. If the cooling power is greater in this zone, the radius and surface area of the curve that creates the curl may be reduced. Thus the overall product size may also be reduced.

(37) FIGS. 4 and 5 show a hair styling device having an arrangement of heating and cooling zones which ensure that the hair is curled regardless of the direction of use. The apparatus is moved linearly across the hair and the arms open and close in a hinged motion.

(38) The curvature of one cooling zone 14 is reversed relative to the curvature of the other cooling zone 14. Both cooling zones 14 curve towards the outer surface of the same arm to ensure that the same curl direction is produced regardless of the direction of movement of the apparatus. Accordingly, one arm (one of the upper or lower arms) has a cross-section which is smaller than that of the other arm.

(39) A similar change in radius of curvature and surface area ratio can be achieved by using a non-planar heating zone. One arm may have a convex contacting surface in the heating zone and the other arm a concave contacting surface in the heating zone.

(40) Such a non-planar heating zone may be incorporated in any of the arrangements. For implementation of today's off the shelf heater technologies with the ability to create good thermal response, it may be most cost effective to use a planar heater. However, a curved surface may be effective to maximise surface area and the radius of the hair within the cooling zone. A curved heating zone may be formed from a curved aluminium plate for example. One particularly useful and durable embodiment of the heating zone may comprise an aluminium plate bearing a plasma electrolytic oxide (PEO) coating of aluminium oxide. This PEO provides a layer of electrical insulation onto which a heater electrode may then be placed to heat the aluminium plate. The PEO layer also increases the durability of the aluminium allowing it to be shaped (and reshaped if necessary) into the desired curve.

(41) The cooling may be provided by air. The air flow direction can be inwards toward the hair in one arm and outwards from the hair as an exhaust in the other arm. Alternatively, there may be an inlet pointing into the hair and passing through the hair from both arms. In this case, one inlet may provide negative pressure acting as the exhaust.

(42) FIGS. 3a and 3b show that the heating zone 16 and cooling zone(s) 14 extend longitudinally along the length of the arm. The resilient suspension 40 and the hinge 41 are both illustrated schematically. In FIG. 3a there is a single cooling zone and thus the apparatus must be used in the direction shown in the arrow to provide curling. In FIG. 3b, there are two cooling zones and thus the apparatus is “ambi-dextrous” and may be used in either direction to provide curling.

(43) As previously explained with reference to FIG. 2b, users have previously curled hair by rotating the hair straightener 180° towards the head prior to pulling the hair 10 through the hot heatable plates in the direction of arrow C. Such conventional hair straighteners are typically made from a plastic housing, such as rynite. The curved outer surface of the hair straightener is then used to form a curl. Such plastic materials are generally poor thermal conductors and so the heated hair cools slowly. Generally speaking, the better the cooling, the longer the hair retains the shape of the curling surface.

(44) FIG. 4 shows a further arrangement of the hair styling apparatus comprising an elongate body 50 which forms a handle for a user to grip the apparatus. A pair of arms 52 are attached to the body. The arms are hinged together at one end where they are attached to the body. The arms are moveable between a closed position in which the opposed ends of the arms are adjacent each other and an open position in which the opposed ends of the arms are spaced apart. In this arrangement, a heating zone and a cooling zone are formed on each arm, with the cooling zones on either side of the heating zone on one arm thermally coupled together by heat transfer means/thermal conductors (depicted as reference 40a on the upper arm and not shown on the lower arm).

(45) In the arrangement of FIG. 4, the cooling system may use a fan, although this is optional and shown here purely for illustrative purposes. Optional fan types that may be used are set out previously in the text referencing FIG. 1. FIGS. 5 to 8 and the supporting text show other cooling system alternatives that may be applied to the hair styling apparatus of FIG. 4.

(46) FIGS. 5-8 show various arrangements of the heating and cooling zones. As previously described, the most effective use of the cooling to create the curl is when the hair is at its hottest point, i.e. when it exits the heater. Referring to FIG. 5, this shows a cross section through the line A′-A′ of FIG. 4 and showing heating and cooling zones arranged to provide an apparatus which curls hair easily. In FIGS. 5 and 6, the styling appliance is shown in use on a user's head 12. The heating and cooling zones are housed within one or both of the arms and the outer surface of the housing 39. As with the illustrations of previous arrangements, the arms are again shown here in the closed position with the hair 10 sandwiched between the two arms. In the arrangement shown in FIG. 5, the contacting surfaces of the two arms are planar in the heating zone 16 and non-planar (i.e. curved) in the cooling zones 14 formed from cooling members 42a and 42b on one arm and 43a and 43b on the other arm. These cooling member may be made from pre-formed metal rods (for convex members 42a, 42b), machined or cast metal for example.

(47) In the arrangements of FIGS. 5-8, the heating and cooling zones are also thermally insulated from one another by insulator 46 in FIG. 5. The thermal insulator minimises heat transfer between the heating and cooling zones. One example of a suitable insulator is aerogel.

(48) The contacting surfaces of each arm in the arrangement in FIG. 5 have complementary shapes to ensure that the hair is in contact with both surfaces through both the heating and cooling zones. This means that the contacting surfaces are generally parallel to each other regardless of whether they are curved or planar. This provides efficient heat transfer/cooling to the hair. The arrangements shown in FIGS. 6 to 8 also have the same complementary shapes on the contacting surfaces of each arm.

(49) In FIG. 5, one arm has a contacting surface having a generally planar section for the heating zone 16 and a convex section 15a for the cooling zones formed from cooling members 42a and 42b positioned either side of the heating zone. The other arm also has a generally planar section for the heating zone but has a concave section 15b for the cooling zone 14 formed from cooling members 43a and 43b. The curvature of the concave sections 15a matches that of the convex sections 15b so that both arms fit together snugly. The planar sections are generally at right angles to the direction of opening and closing the arms. On each arm, the cooling members 42a, 42b, 43a and 43b may extend along each arm along side the heating plates.

(50) We define the “curl factor” as the ratio of the length of straight to curled hair. It has been observed generally speaking, that the smaller the radius ‘r’ (see FIG. 5) of the curved cooling member, the tighter the curl produced, i.e. the curl factor improves as the radius of the curved cooling members decreases. Moving from a 16 mm radius to a 10 mm improves the curl factor by approximately 20% meaning that tighter curls are produced. Moving from a 16 mm radius to a 6 mm radius curve on the cooling members improves the curl factor by approximately 60%—even tighter curls. Setting the cooling members in the cooling zone to a radius between 2 mm to 10 mm has been observed to provide pleasing curls. One preferred radius ‘r’ of the curve cooling members is 6 mm. These described radii similarly apply to previous arrangements comprising curved cooling zones.

(51) As set out previously, plastic materials such as rynite are generally poor thermal conductors and so the cooling members may alternative be formed from materials with a better thermal conductivity to improve the cooling of the hair. The cooling members may be formed from metal, such as copper or aluminium and arranged as curved bars, separated from the heatable plates by a thermal insulator such as aerogel. These cooling members provide rapid cooling and curling of the hair on the curved surface compared to plastics. Experimental data shows a curl factor improvement of up to 85% of copper against plastic cooling members. It will be appreciated however that cheaper materials, such as aluminium may be preferred.

(52) In FIG. 5 the cooling members are positioned on both sides of the heating zone such that the direction of use is not critical. This allows the styling apparatus to be used in either direction, making styling easy on each side of the head 12 and allowing for left or right handed use. It some arrangements however this may not be essential and the cooling members may be placed on one side only to reduce both weight and cost of the apparatus. With cooling members present on only one side (i.e. to the left or right of the heating zone as viewed), the hair styling apparatus may be used in one direction to straighten hair, and in the other direction to curl hair.

(53) During use, the cooling members may warm up if there is no mechanism to dissipate the heat transferred from the hair. The longevity of curls is reduced and the diameter of curls increases as the cooling members warm up. The overall curling performance may drop significantly should the cooling members rise in temperature from 30 to 70° C. FIG. 5 shows one arrangement of the apparatus for addressing this. Experiments have shown that limiting the temperature of the cooling members to around 50° C. leads to effective styling and curl longevity. However, it will be appreciated that initially, at turn on, these cooling members may be at a much lower temperature. In some arrangements the cooling members may also be heated, to around 50° C. for example, in order to provide consistent cooling to when the apparatus is fully heated and in use. This allows for a consistent curl style to be produced.

(54) In FIG. 5, thermal conductors 40a and 40b provide a heat bridge between the respective cooling members on either side of each arm to transfer heat between the cooling members. This heat bridge may take the form of a metal plate or series of pipes/bar acting as a conductive member within one or both arms. The heat bridge (heat sink) may be made from a good thermal conductor—preferably a metal such as aluminium. In some arrangements the heat bridge and cooling members in one arm may be manufactured as a single unit. Variants of the heat bridge may use a heat pipe for heat transfer or pumped fluid. The heat pipe may be of at least 5 cm in length in order to work effectively.

(55) FIG. 7 depicts a variant of the FIG. 5 arrangement. Only the upper arm is shown but the same technique may be implemented on the lower arm as well. In FIG. 7, cooling fins 47 extend into the void to provide a heat sink/radiator like arrangement by increasing the surface area. Referring to FIG. 4, the heat bridge/heat sink 40a is shown in dotted lines (denoting that it is present inside the outer plastic casing. Combining the heat bridge/heat sink with the fan 54 in FIG. 4 enables air to be blown through the cooling fins to improve the cooling of the heat sink and the cooling members. Driving air through the void and fins of the heat bridge/heat sink means the fan can generate less air pressure than through arrangements using tubes or holes in the cooling members. This means the fan size may be reduced and/or a lower revolution speed used leading to a quieter fan. To improve efficiency further, a further thermal insulator may be included in a portion of the void between the heatable plate and heat bridge/heat sink. In this arrangement it may not be necessary to provide a thermal link between cooling members on either side of one arm—each may be cooled independently by air flow through the cooling fins.

(56) In FIGS. 5 and 6, hair on the head of user 12 is to be styled. To style hair, a user puts hair in the styling apparatus then rotates the hair styling apparatus of FIG. 5 by 90° towards the head prior to pulling the hair 10 in a linear fashion through the hot heatable plate (turning the apparatus 90° is less counter-intuitive to a user than turning through) 180°. By pulling hair through, such that the apparatus moves along the hair in the direction of arrow A in FIG. 5 (the apparatus itself may be moved in direction C or D relative to the head of the user 12), hair is first pulled over cooling members 42b and 43b (which now provide pre-heating) and then through the heating zone 16. As the hair 10 is pulled over cooling members 42a and 43a, the hair is rapidly cooled and curled.

(57) Heat transfer from the hair to the cooling members 42a and 43a is transferred via the respective thermal conductor to respective cooling members 42b and 43b. This leads to cooling members 42b and 43b heating up as a result of the heat transfer. Elements 42b and 43b then effectively act as pre-heating elements, returning heat extracted from the cooling and curled hair back into sections of hair still to be heating and styled.

(58) Operated in reverse, with hair pulled through in the direction of arrow B, hair is first pulled over cooling members 42a and 43a (which now provide pre-heating) and then through the heating zone 16. As the hair 10 is pulled over cooling members 42b and 43b, the hair is rapidly cooled and curled. Heat transfer from the hair to the cooling members 42b and 43b is transferred via the respective thermal conductor to respective cooling members 42a and 43a.

(59) In FIG. 5, as styled hair exits the right hand (as viewed) cooling zone 14 formed from cooling members 42a and 43a, hair is turned through a further 90 degrees (or more) over the edge of cooling member 43a. This change of direction may be in the opposite direction to the previous curling (the hair may take an “S” shaped path. Any subsequent cooling of the hair during this second change in direction may lead to the quality of the curled hair style being comprised—the curled and cooled hair has now been turned in a second direction following heating and cooling which may affect the overall quality and appearance of the curl. FIG. 6 illustrates one way of addressing this problem.

(60) In FIG. 6, curl guides 44a, 44b, 45a, 45b are positioned on the outer edges of the cooling members. These guides are generally formed of a material with poor thermal conductivity, which may be the same material as the hair styler housing, such as rynite.

(61) The guides are arranged to guide the hair through a further 90 degree turn, but in the opposite direction to the cooling members. The guides may be separate components or an integral parts of the hair styler housing. In this way, hair exits the styling apparatus in the same direction as which it entered, meaning that the hair styling apparatus can be pulled in a generally linear fashion along the hair, without holding the apparatus at 90 degrees to the head. In FIG. 6 for example, it can be seen that the styling appliance, when pulled in direction A to style hair on the side of user's head 12, does not need to be held at 90 degrees to the head 12.

(62) Forming the guides from a material of poor thermal conductivity compared to that used on the cooling members reduces heat loss from the curled hair as it passes over the guides. This reduces impact to the styled hair as it turns in the opposite direction on exiting the cooling zone.

(63) The guides have further benefits, helping to protect the cooling members from accidental scratching, denting and minimising any heat transfer when the stylers are placed on a surface after use.

(64) In another variant, such as that shown in FIG. 10, the styling apparatus again has cooling zones 14 and heating zone 16, but here the apparatus may have a curved cooling zone 150 on one side, and a flat cooling zone 152 on the other. In this way, hair may be heated, cooled and curled using the styling apparatus in one direction, then heated, cooled and straightened by using the styling apparatus in the opposite direction. A heat bridge 154a, 154b may again be used in this arrangement.

(65) A further variant is shown in FIG. 11. The arrangement of FIG. 11 is used for straightening hair. Here both cooling zones 160, 162 are generally planar (it will however be appreciated that only one side may have cooling zones, and the other side may have no cooling zone if the apparatus is to be used in one direction only). In an arrangement with dual zones, either side of the heating zone, the heat bridge 164a, 164b may again be used to thermally link the cooling zones and provide for improved cooling. As with the other arrangements described herein, again features such as cooling fins, active cooling mechanisms (fluid cooling and the like), and/or a fan may be used in order to improve the cooling. The cooling zones may also include heating, to a temperature below that of the heating zones, in order to provide uniform cooling of hair.

(66) FIG. 8 shows a further arrangement of the cooling members through one arm of device of FIG. 5. In this arrangement the cooling members include one or more conduits within the cooling members in which a fluid (gas or liquid such as water) can be pumped. The fluid may be delivered at a high pressure to ensure that it provides effective cooling and rapid transfer of the heat. Such an arrangement may include members of the other arrangements, such as the heat sink/heat bridge of FIGS. 5 and 7 to provide means for cooling the pumped fluid.

(67) As set out for the previous arrangements, a phase change material may also be used to draw heat out of the cooling members in FIGS. 5 to 8. Such a material may replace or be connected to the heat bridge 40a in the cooling zone. Residual heat is built up within the phase change material (latent heat) and can be dissipated between use or strokes, e.g. by using air. Suitable phase change materials include wax and/or water.

(68) To control the direction that a curl forms in, in use, a user may move the hair styling apparatus along the hair to be styled at an angle offset (angle θ in FIG. 14) to the direction of movement. As shown in FIG. 9, the apparatus is angled so that the one of the heatable plate, furthest away from the hinge end, leads the other end of the heatable plate. The curl direction is reversed by changing the angle offset so that the end of the heater closest to the hinge end leads the end further away. Such a technique is useful to ensure the hair style is balanced on either side of the head and is applicable to all the arrangements described.

(69) In all of the arrangements described above, direct contact between two parallel plates is critical to achieve efficient heat transfer to the hair. Achieving uniform heat up of the entire hair section is critical for curl retention. The efficiency of the heat transfer created by two heater plates creates a flow of heat energy into the hair. By the addition of responsive temperature of control of this surface, the temperature of hair within the apparatus is maintained with the movement of the plates along a hairs section. The curl style (shape) of the hair is created when the hair cools whilst it is maintained in a shape.

(70) By contrast, heating hair from a single surface (or side) is less efficient and relies on the heat transferring through the hair. However, hair is a good thermal insulator and this process takes time. One disadvantage is that such an apparatus cannot be simply moved along the hair. Furthermore, there is a temperature difference across the section of hair within the apparatus and this means that individual hairs within the section may curl different amounts or behave differently. This may create fly always and may additionally cause poor longevity of style. This is because that if the individual hairs are not behaving uniformly, the tighter curling fibres may end up supporting the weight of others and hence drop out more quickly.

(71) All of the arrangements described above also achieve even cooling through all the hairs making up a section. This is critical to preventing uneven curl retention to individual hair fibres creating fuzzy hair. Without this cooling, the user has to control the rate at which the apparatus is used.

(72) In each arrangement, the hair is preferably heated to a temperature above 160° C. in the heating zone. The hair is preferably reduced in temperature in the cooling zone(s) to a temperature which is less than that in the heater zone. There is little style advantage in cooling the hair to less then 90° C. Accordingly, the hair is preferably cooled to a temperature between 90° C. and 160° C. This may be achieved by limiting the temperature of the cooling members in arrangements shown in FIGS. 4 to 10 to a maximum of 50° C. Generally speaking however, the cooler the hair becomes in the cooling zone the more effectively the hair retain the shape it is held in though the cooling zone. The heating and cooling is preferably stable at the preferred temperature.

(73) To retain a stable temperature in the cooling zones, the cooling zone following the heating zone (i.e. the cooling zone in which hair exits the appliance), may be temperature regulated, which may involve heating the cooling zone to a temperature less than that used in the heating zone, in particular when the apparatus is started from cold. Both cooling zones may also be temperature regulated. In this way, the temperature of the cooling zone(s) may be held stable such that consistent styling curling is possible. The implemented cooling system may then actively switch between cooling the cooling zone and heating the cooling zone in order to retain a stable temperature, cooler than that of the heating zone. FIGS. 7 and 8 show one arrangement of introducing heater elements into the cooling zones. In FIG. 7 heater elements 100, 101 may be coupled to the cooling members (should the cooling members be metal, the skilled person would appreciated the heater elements would need to be electrically insulated). In FIG. 8, similar heater elements may be used, or alternatively, a heated fluid may be routed through the conduits. It will be appreciated that such heating in the cooling zones is entirely optional and many arrangements may choose not to provide such heating.

(74) By maintaining a constant stable heater input temperature and a continuously flow of air cooling the hair the user is able to create tighter or looser curls by altering the rate at which they draw the product through the hair. Generally, the faster the movement, the straighter the hair and the slower the movement of the apparatus, the curlier the hair. The rate of movement is limited by the heater input temperature. It is also critical to cool the hair all the way though the section to achieve this. For curling, a suitable rate may be between 10 and 30 mm/s.

(75) The nature of the curl generated will also depend on the amount of hair input and the nature of the hair. Inputting a section of straight hair may create one or more locks of curls dependant on the size of the section and the tightness of the curls created. This is because of the natural relationship that curly hair displays, i.e. to form locks of curls. Naturally curly hair can be curled to the desired size of curl in the same way straight hair can be curled.

(76) As described above, the most effective place to cool the hair (to retain a curved shape) is at its hottest point when it exits the heater and its curvature is greatest. Furthermore, as described above the most effective cooling is achieved in arrangements directing air onto the hair by creating the optimal balance between the air's pressure, volume flow rate and aperture size. Other effects can be created by altering the design of the apparatus. For example, “shine” and soft feeling hair could be created by directing the air direction in a downward direction, i.e., helping to close the cuticle. Air flowing in the opposite direction could have a detrimental effect on the hairs' shine. In other arrangements, such as those in FIGS. 5 to 9, ensuring that the hair is only cooled and curled in one direction (i.e. there is no further cooling and curling in a different direction) also leads to improved curls.

(77) The addition of negative ions in the air stream (created in any known manner, e.g. by a high voltage needle could help reduce static charge built up in the hair due to motion of use. On a small scale it is thought that the negative ions will help to close the cuticles of the individual hair fibres creating additional shine.

(78) No doubt many other effective alternatives will occur to the skilled person. It will be understood that the invention is not limited to the described embodiments and encompasses modifications apparent to those skilled in the art lying within the spirit and scope of the claims appended hereto.

(79) Through out the description and claims of this specification, the words “comprise” and “contain” and variations of the words, for example “comprising” and “comprise”, means “including but not limited to, and is not intended to (and does not) exclude other moieties, additives, components, integers or steps.

(80) Throughout the description and claims, the singular encompasses the plural unless the context otherwise requires. In particular, where the indefinite article is used, the specification is to be understood as contemplating plurality as well as singularity, unless the context requires otherwise.

(81) Features, integers, characteristics or groups described in conjunction with a particular aspect, embodiment or example, of the invention are to be understood to be applicable to any other aspect, embodiment or example described herein unless incompatible therewith.