Abstract:
The present invention relates to a hair styling appliance comprising a handle portion and a heating portion with a preferably dome-shaped heating zone for heating and styling hair, and a cooling portion with a cooling zone for cooling the hair thus styled, wherein the difference in temperature between the surface temperatures of the heating zone and the cooling zone amounts to at least 80 kelvin and, more particularly, 100 kelvin. The present invention also relates to a method of styling hair, especially using a hair styling appliance with the above-mentioned features.

Description:
This is a continuation of PCT application Ser. No. PCT/EP98/06092, filed Sep. 24, 1998, which claims priority from German application serial number 19748067.5, filed Oct. 31, 1997, (pending). 
    
    
     The present invention relates to a hair styling appliance with a handle portion, a heating portion with a preferably dome-shaped heating zone for heating and styling, especially curls or waves of hair, and a cooling portion with a cooling zone for cooling the styled hair. Further, the present invention relates to a method of styling hair, especially by means of the hair styling appliance of the present invention. 
     Appliances and methods of the above-mentioned type are known from the state of the art. German patent application No. 32 15 232, for example, discloses a method of styling a strand of hair by heating and a hair styling appliance for this purpose. In this arrangement, the air supplied by an air blower is conducted partly via a filament winding to a heated air chamber of a cylindrical curler member and exits through radial heated-air discharge openings. Cooling air enters into a cooling air chamber of the curler member through a bypass channel which is passed by the heating filament. The hair strand to be styled is wrapped around the curler member which is then moved away from the scalp, with the hair strand initially sliding over the outside wall of the heated air chamber and subsequently over the outside wall of the cooling chamber. The hair strand is heated and cooled thereafter. However, a tool of this type does not permit achieving satisfying results, because the waves and/or curls thereby produced in the hair are not sufficiently permanent. 
     A similar appliance and a method is also described in non-published application PCT/EP97/02064 of the applicant which, by express reference, is herewith included in the disclosure of the present patent application. The said application discloses a hair styling appliance with a handle portion, a heating portion with a heating zone for heating the hair, a cooling zone and a styling element for styling the hair. The styling element is configured as a styling edge, with this styling edge being arranged subsequent to the heating zone and the cooling zone following the styling edge so that a hair strand being styled can be heated at the heating zone, the heated hair strand can be styled at the styling edge, and the so restyled hair strand can be cooled in the cooling zone. This application further includes a method of styling hair, especially implemented in a hair styling appliance according to the previous description. 
     On the one hand, it is not possible with the hair styling appliances known from the prior art to produce a permanent curl or wave in a strand of hair. On the other hand, a complicated construction is necessary, or handling of the appliance is intricate for the user, especially when curling or waving hair. 
     SUMMARY OF THE INVENTION 
     An object of the present invention is to provide a hair styling appliance which is improved compared to the state of the art and a method of employing the hair styling appliance so as to ensure a maximally permanent set for a hair strand which is styled by way of the appliance, more particularly, a curl or wave in a hair strand which is produced by way of the appliance and, respectively, the method. On the other hand, an additional objective of the appliance is to render possible simple handling by a user, with the handling necessitating only few and simple manipulations. 
     According to the present invention, this object is achieved, on the one hand, by a hair styling appliance which includes a handle portion, a heating portion with a preferably domeshaped heating zone for heating and styling, especially curls or waves of hair, and a cooling portion with a cooling zone for cooling the styled hair, wherein the difference in temperature between the surface temperatures of the heating zone amounts to at least 80 kelvin, more particularly, 100 kelvin, or more. This object is achieved, on the other hand, by a method which suggests using the appliance of the present invention. An object of this type provides for a hair styling appliance which requires little effort and structure and is easy to handle due to its simple design. Favorably, the object of the present invention achieves an improved permanence of the curls or waves of a hair strand is reached because “freezing” of the styled hair, especially the curls or waves in a hair strand, occurs only with a temperature difference of at least 80 kelvin between the heating and cooling zones, which is essential for the present invention, with the result of permitting an improved permanence of the curls. Thus, the object of the present invention discloses a hair styling appliance which is advantageously adapted for treatment of straight, curled, or waved hair. 
     In a favorable aspect of the present invention, the heating and cooling portions together provide a styling member for hair treatment, with the styling member generally having a circular, elliptical, or similar cross-sectional surface. This provides a simple handling with the heating and cooling portions incorporated in one single styling member. In addition, an essentially symmetrical arrangement of the cross-sectional surface of the styling member for the heating and cooling portions, for example, in two semicircular cross-sections, permits achieving a heating zone and a cooling zone of generally equal size. This has proved advantageous for a sufficient heating and subsequent cooling. 
     In an improvement of the present invention, the heating and cooling zones are arranged on the outer surfaces of the heating and cooling portions, which are dome-shaped in particular, so that favorably the maximum possible surface for heating and/or cooling is made available. The especially plane inside surfaces of the heating and cooling portions are arranged so as to be opposite and spaced from each other, with the result that a minimum possible temperature influence of the heating portion on the cooling portion and vice-versa occurs. Preferably, the distance between the two inner surfaces amounts to 1.5 to 3 mm approximately. 
     Advantageously, a thermal uncoupling element, for example, an insulator, is provided between the heating portion and the cooling portion so that it is almost ruled out that the temperatures of the two components will influence each other. 
     In a particularly favorable embodiment of the present invention, a pressing means, for example, a hair retaining clip for exerting a pressing force on the hair being styled is provided. Strands of hair can be placed between the heating portion and the pressing means. A good heat contact of the hair with the heating portion is thereby achieved, on the one hand, and a tension force acting on the hair can be produced, on the other hand, which must be exerted by a user when the hair styling appliance, starting from the hair roots, is pulled over the strand of hair. 
     The pressing means, more particularly, the clip, is movably attached to the handle portion or the heating portion of the appliance. Especially, one end of the clip is coupled by a pivot to the handle portion or the heating portion and urged by a spring element against the heating portion. Also, the clip may be so fixed that a uniform gap is produced between it and the heating portion when it in its unloaded inactive position, i.e., when no hair is placed between clip and heating portion. The tension force can favorably be set to the desired amount by an appropriate selection of the spring element and the gap size. Preferably, the tension force that is necessary to pull the hair styling appliance from the strand ranges between 1 and 2 Newton. 
     The present invention further discloses manufacturing the clip from a heat-conducting material so that it favorably also heats the hair strand. 
     In a preferred aspect of the present invention, the heating portion comprises a member made of an appropriate heat conducting material, for example, metal, or a similar material. The surface temperature of this member in the area of the heating zone amounts to at least 120° C., preferably however about 145° C., in order to reach the styling temperature of roughly 120° C. required in the hair with a relative moisture of roughly 30% in the hair. 
     The heating portion itself includes an electric heating element, for example, a PTC element, an electric heating spiral, or a similar member. As an alternative, however, the heating portion may also been heated by a gas heating appliance, e.g. a heating appliance with catalytic combustion. It is especially advantageous, however, to position a PTC element in the heating portion. 
     In another preferred aspect, the cooling portion comprises a member made of metal, such as aluminum, or also plastics, or the cooling portion has a heat-conducting coating and/or cooling ribs. This provides the best possible heat dissipation of the hair which is previously heated and then passed over the cooling portion so that the temperature difference is adjustable which is necessary for successfully styling curls. 
     What has been found to be especially favorable is a cooling portion which comprises a cooling member that can be cooled actively, for example, a member which can be cooled by cooling air, a Peltier element, or a similar element. An arrangement of this type permits adjusting the temperature difference according to the present invention in a particularly advantageous manner so that particularly good styling results and a great degree of permanence of the curls can be achieved by means of an actively cooled cooling member. 
     In another embodiment of the present invention, it is proposed that the cooling portion, and/or the clip, and/or the heating portion have guiding and/or spacing means, more particularly ribs, on the outer surface. On the one hand, the said means advantageously permits guiding the hair strands adapted to be wrapped around the styling member of the appliance and, on the other hand, the means, in its capacity as a spacing means, prevents a user from getting into contact with the hot surface of the heating portion, or, respectively, the clip. 
     The ribs are arranged substantially transversely to the main axis of the appliance so that two adjacent ribs form in each case a channel that is circumferential to the heating portion, and/or the cooling portion, and/or the clip. Favorably, the hair strand being styled can simply be placed into the channel which allows safely guiding the hair strand. 
     At least one rib of the hair styling appliance is adapted as a boundary rib so that the hair strand which is wrapped around the heating portion and/or the cooling portion is secured by this rib against slipping off from the heating portion, the clip, and/or the cooling portion in a favorable fashion. 
     In a special embodiment, the two external ribs of the cooling portion are designed as boundary ribs so as to project over the remaining ribs, in particular those at the cooling portion, in a plane transverse to the main axis of the appliance at least in areas. This achieves guiding of the hair strand which is adapted to be wrapped around an area of the hair styling appliance, thereby preventing the strand from either slipping off from the tip of the appliance towards the front or from the handle portion of the appliance towards the rear end. 
     Preferably, the ribs are provided on at least one component part, especially the clip, in a bow-shaped, waved or arrow-shaped configuration. It is advantageously achieved with this design of the ribs that the strand which is wrapped around this component part experiences a higher amount of friction than on the other component part, especially the cooling portion. The reason is to prevent the user from pulling the hair strand across the outer surface of the clip. 
     In a special design, the ribs of the clip are arranged generally in parallel to the main axis of the appliance. This is meant to expediently provide both an optical barrier and a mechanical obstacle, particularly by an increased frictional resistance of the hair in order to prevent the user from pulling the hair across the outer surface of the clip. 
     In a particularly favorable manner, the ribs are arranged substantially radially in relation to the main axis of the appliance. Thus, the ribs extend substantially vertically outwards from the outer surface of the appliance, escpecially, from the clip or the cooling portion. 
     In another embodiment of the present invention, the appliance, especially the handle portion, has a generally elliptical, oval, or similar outside contour in a plane that is vertical to its main axis. The advantage of such a handle portion configuration is that the handle feels more pleasant in the hand of a user, and the user finds it uncomfortable to turn the hair styling appliance around its longitudinal axis several times, as is common with the majority of hair curling irons of the art. The object of this handle portion configuration is to contribute to the novel type of handling of the appliance which clearly distinguishes over the use of state-of-the-art appliances inasmuch as the appliance, other than a curling iron which is turned several times around its longitudinal axis and with the hair being wrapped around a curler member, is pulled away from the hair roots of a user. 
     The cross-sectional surface of the handle portion decreases continuously from the front towards the rear free end of the handle so that, advantageously, the user is enabled to grip the appliance in a comfortable and ergonomical way. 
     In a special design of the present invention, which can also represent an independent invention, a method of styling hair is disclosed, more particularly, with a hair styling appliance of the present invention, wherein initially a hair strand that is to be styled, especially dry hair, is heated at a heating zone of a heating portion, styled by way of a preferably dome-shaped surface of the heating zone, and the so heated and styled hair strand is subsequently cooled at a cooling zone. According to the present invention, the surface temperatures of the heating zone and the cooling zone are set so that the temperature difference between both zones amounts to at least 80 kelvin, in particular, 100 kelvin, or more. It is necessary for application that the temperature difference of the present invention is reached or exceeded in order to render possible a sufficient cooling of the heated hair strand and “freezing” of the previously styled hair strand, especially the curl, so that a permanent curl can favorably be produced. 
     Advantageously, the hair is heated in the heating zone at least to a styling temperature, with the latter temperature, also called glass temperature Tg, e.g. amounting to roughly 120° C., with a relative moisture in the hair of 30% approximately. A particularly advantageous result is achieved with the method of the present invention when the surface temperature of the heating zone preferably amounts to 145° C. approximately. 
     To achieve appropriate curling results, the hair is pulled in a tightened condition over the heating zone and the cooling zone. Shaping curls is favored by this tightened condition of the hair. 
     To produce the necessary tightening of the hair, the hair is placed into a clamping area between a pressing means, such as a hair retaining clip, and the heating portion, and a clamping force is thereby applied to the hair being styled. The heated hair is then pulled through the clamping area and along the cooling zone. The retaining force which is produced by the retaining clip in this movement counteracts the tension force which must be generated by the user for the movement of the hair styling appliance relative to the hair. 
     The direction of movement of the hair behind the heating zone, that means after the hair has left the clamping area, is equal to the direction of movement in the heating zone. This permits a uniform and favorably low tension force on the hair. A change in the direction of movement of the hair is thus favorably avoided. The shape and permanent set of the curls can be influenced by the relative speed between the hair styling appliance, especially the styling member, and the hair. Thus, a slow movement of styling member and hair favorably achieves a styled curl of small size, while a quick passage achieves a generously styled curl or wave. 
     Favorably, the method of the present invention permits effectively curling straight hair from the roots to the tip of the hair without the use of a curler member which was required in the majority of the previously known methods. Further, the hair styling process attainable with this method is reversible. 
     As an alternative, the method of present invention also permits straightening curled or waved hair by configuring the heating and cooling zones as plane areas arranged one behind the other, for example. 
     It is suggested for a particularly favorable application of this method that the hair be placed particularly close to the hair roots into the clamping area between heating portion and hair retaining clip, and that the hair styling appliance is turned about its main axis by roughly 120° to 180° so that the hair will bear against the heating zone and at least in areas against the cooling zone of the cooling portion. Subsequently, the hair styling appliance is moved away from the head of a user. The heated and styled hair is cooled at the cooling zone of the cooling portion, i.e., the styled, especially curled or waved hair is “frozen” by the temperature difference according to the present invention between the surface temperatures of the heating zone and the cooling zone of at least 80 kelvin. 
     Further features, advantages and possible applications of the present invention can be seen in the following description of embodiments which are illustrated in detail in the accompanying drawings. All features described and/or illustrated, individually or in any desired combination, form the object of the present invention, irrespective of their combination in the claims and their appendency. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     In the drawings, 
     FIG. 1 is a systematic longitudinal cross-sectional view of a hair styling appliance. 
     FIG. 2 is an enlarged view of a styling member, in a cross-section taken along line  2 — 2  in FIG.  1 . 
     FIG. 3 is a top view of a hair styling appliance in an alternative embodiment with arrow-shaped ribs. 
     FIG. 4 is a top view of a hair styling appliance similar to the representation in FIG. 3, however, with longitudinal ribs. 
     FIG. 5 is a bottom view of a hair styling appliance according to the representation in FIG.  3 . 
     FIG. 6 is a side view of a hair styling appliance according to the representation in FIGS. 3 and 5. 
     FIGS. 7 and 8 are views of a hair styling appliance taken along portions  7 — 7  and  8 — 8  in FIG.  6 . 
     FIG. 9 is a side view of a hair styling appliance similar to the representation in FIG. 6, however, with a longitudinal rib on the back side of the clip. 
     FIG. 10 is a perspective view of a styling member for a hair styling appliance in an alternative embodiment. 
     FIG. 11 is a view of a styling member similar to the representation in FIG. 2, however, with a strand of hair inserted. 
     FIG. 12 is a view of a styling member similar to FIG. 11, however, in a representation which is turned by 180° with respect to FIG.  11 . 
    
    
     DETAILED DESCRIPTION 
     A hair styling appliance  1  (FIG. 1) of the present invention generally includes a handle portion  6  and a styling member  7  which, in turn, includes a heating portion  8 , a cooling portion  10 , and a clip  9 . A cover  19  is provided at the front tip of the appliance  1 . At its rear end, clip  9  has a push button  11  which is supported in the handle portion  6  by way of a spring element  12 . 
     An electric switch  13  for switching the appliance on and off is arranged on the outside surface of the handle portion  6  opposite to the push button  11 . A cable  14  for the mains connection of the appliance is provided at the rear end of the handle portion  6 . The interior of the handle portion  6  houses a motor  15  for driving a fan wheel  16 , and a plate bar  17  with control appliances. The motor  15  can be driven alternatively by way of electrical voltage dividers, or e.g. by a battery. The hair styling appliance  1  has a generally symmetric configuration about its main axis  18 . 
     The styling member  7  (FIG. 2) has a substantially elliptical cross-section which is formed of two halves having essentially the same size. The mean diameter of a styling member  7  advantageously ranges between 15 and 40 mm approximately. One half (the bottom one) is a cooling portion  10 , the top half is a heating portion  8 . There is provision of an arcuate clip  9  on the top side of the heating portion  8 . 
     A PTC element  20  is arranged in the interior of the heating portion  8 . The dome-shaped outside surface of the heating portion  8  forms the heating zone  21  which, in the unloaded condition of the appliance, i.e., in the absence of hair placed between the heating portion  8  and the clip  9 , bears directly against the inside of the clip  9  in a favorable manner. However, it is also possible to attach the clip  9  so that it has a gap  22  relative to the heating zone  21 , as illustrated in FIG.  2 . The heating portion  8  and the clip  9  have surfaces which are opposite to one another and substantially congruent in shape. Further, the clip  9  is favorably made of a heat-conductive material, e.g. aluminum, so that the clip  9  may also be heated indirectly by the heating portion  8 , with the result of permitting heating both sides of a strand of hair which is to be placed into the interspace between the heating portion  8  and the clip  9 . 
     Inside the cooling portion  10  is a cooling channel  23  which penetrates the length of the cooling portion. The dome-shaped outside surface of the cooling portion  10  forms the cooling zone  24 . The cooling air propagates from the fan wheel  16  into the interior of the cooling portion  10  and from there to the outside through radial openings (which are not shown for the sake of clarity). Advantageously, the outlet openings vary in their diameter in an axial direction in order to achieve a uniform air distribution along the cooling portion  10 , that means, the openings are larger proximate the handle portion  6  than proximate the tip  19  of the appliance. As an alternative of the above-mentioned design with an active cooling, the member of the cooling portion  10  can also be provided as an aluminum member with a paraffin filling. 
     The two substantially plane inside surfaces of the heating portion  8  and the cooling portion  10  are arranged at a distance  25  relative to each other, which is preferably penetrated by air, but wherein also a thermal insulator  26  may be accommodated. It is thereby avoided that the cooling portion  10 , too, is heated by the radiation heat of the heating portion. The surface temperature of the heating portion  8  advantageously amounts to 120 to 145° C. approximately. The cooling air which flows through the cooling channel  23  and is produced by the fan wheel  16 , as shown in the representation of FIG. 1, will cool the cooling portion  10  basically to room temperature so that the temperature difference according to the present invention between the two surface temperatures of the heating zone  21  and the cooling zone  24  at least amounts to 80 kelvin. 
     The appliance illustrated in FIGS. 1 and 2 is comprised of a heating portion  8  and a cooling portion  10  with a substantially smooth outside surface, while the clip  9  has on its outside transverse ribs which extend substantially vertically relative to the main axis  18  of the appliance  1 . 
     An alternative embodiment with respect to the hair styling appliance illustrated in FIGS. 1 and 2 is shown in a top view in FIG. 3, similar to the view  3  in FIG.  1 . The appliance  30  basically includes a handle portion  31  and a styling member  32 , and the clip  33  has arrow-shaped ribs  35  on its outside surface. Ribs  35  are arranged substantially symmetrically in relation to the main axis  37  of the appliance  30 , and their tips point to the front end of the appliance. The two longitudinal edges of the clip  33  have undulated outside ribs  36 . The purpose of the ribs  35  and  36  is to make a user aware of not pulling a strand of hair being styled over the ribbed outside surface of the clip  33 . Clip  33  has a push button  34  for actuation at its rear end. The handle portion  31  has a roughly truncated-cone-shaped configuration which tapers continuously towards its rear end and is rounded at this rear end. 
     Another alternative (FIG. 4) of the design of a hair styling appliance shown in FIG. 3 also includes a handle portion  31  with a main axis  37 , however, the styling member  38  is furnished with longitudinal ribs  40  on the outside surface of the clip  39 . The longitudinal ribs  40  extend substantially in parallel to the main axis  37 , and their design is meant to prevent a user from wrapping hair around the styling member  38 . The visual impression inducing a user not to pull the hair over the clip can still be augmented by undulated outside ribs  41  on the two longitudinal edges of the clip  39 . 
     The bottom side of a hair styling appliance  30  according to FIG. 3 corresponds to an illustration in view  5  of FIG.  1 . The embodiment of FIG. 5 shows a cooling portion  42  with transverse ribs  43  which extend substantially vertically to the main axis  37  of the appliance. Thus, ribs  43  form a number of parallel channels into which a strand of hair to be styled is placed and can be pulled tranversely to the main axis  37 . A switch  44  which basically corresponds to the switch  13  of FIG. 1 is arranged at the front end of the handle portion  31 . 
     Alternatively to the previously described electrical heating of a hair styling appliance of the present invention, the latter appliance may of course also be operated by means of a catalytic combustion of gas. It is favorable in such a case to accommodate a gas cartridge in the handle portion  31 . For ease of fitting the gas cartridge into, or for its removal from, the handle portion  31 , the latter may be split into a front casing shell  45  and a rear casing shell  46  that is removable therefrom. 
     In a side view (FIG. 6) of an appliance according to the illustration in FIGS. 3 and 5, one can see the handle portion  31  and the styling member  32 , with the latter including the cooling portion  42  and the clip  33 . The arrow-shaped ribs  35  on the outside surface of the clip  33  have a forward inclination. Close to their bottom end, the ribs  35  may still be interconnected by a longitudinal rib  47 , with this impression preventing a user even more from pulling the hair strand being styled over the clip  33 . 
     The cooling portion  42  includes a plurality of parallel ribs  43  which have a front and a rear boundary rib  48 ,  49 . Ribs  48 ,  49  extend over the remaining intermediate ribs  43  at least in areas in a radial direction. Channels  50  for guiding the hair strand being styled are provided intermediate the individual ribs  43 ,  48 , and  49 . 
     It can be seen in a cross-section (FIG. 7, FIG. 8) taken along the lines  7 — 7  and  8 — 8  in FIG. 6 that the cross-sectional surface of the casing shell  45  increases from the rear to the front end of the handle portion  31 . The handle portion  31  is provided with push button  34  on its top side and switch  44  on its bottom side. 
     An improvement upon a hair styling appliance (FIG. 9) according to the illustration in FIG. 6 basically includes the handle portion  31  with push button  34  and switch  44 . In contrast to the illustration according to FIG. 6, a vane-shaped longitudinal rib  51  is provided on the top side of the clip  33 . Rib  51  joins in between the tip  52  and the push button  34  so that it ascends towards the handle portion  31 . A longitudinal rib  51  of this type in combination with the longitudinal rib  47  still intensifies the awareness of a user not to place or pull a hair strand being styled across the surface of the styling member  32 . 
     Another alternative design of a hair styling appliance according to the present invention (FIG. 10) basically includes a handle portion  53  and a styling member  54 . The latter styling member  54 , in turn, is comprised of a heating portion  55  and a cooling portion  56  which are separated from each other by a longitudinal gap  58 , into which also a thermal insulator may be inserted. Arranged on the top side of the heating portion  55  is a clip  57  with push button  60 , and by pushing the button  60  the clip  57  is adapted to be pivoted about a pin  61 . This renders it possible to place a hair strand being styled into the wedge-shaped interspace which is then produced between the clip  57  and the heating portion  55 . In its area diametrally opposite to the clip  57 , the cooling portion  56  has ribs  61  which extend substantially transversely to a main axis  62  of the appliance. What is characteristic of the representation shown in FIG. 10 is the generally circular cylindrical shape of the styling member  54  which becomes also apparent from the bowl shape of the frontal cover  59 . 
     The typical mode of operation of the hair styling appliance of the present invention is illustrated in FIGS. 11 and 12. A hair strand  64  being styled close to the hair roots  63  is placed into gap  22  and clamped in between the heating portion  8  and the clip  9 . Initially, the push button  11  is on the upward directed side of the appliance. Subsequently, a user will turn the handle portion  6  by about 180° in the direction of rotation  65  so that the push button  11  (FIG. 12) will be placed on the bottom side of the appliance. In this arrangement, the hair strand  64  being styled is urged by the clip  9  against the heating zone  21  of the heating portion  8 , on the one hand. On the other hand, the strand  64  is placed at the cooling zone  24  of the cooling portion  10 . To produce curls, the hair styling appliance is now pulled away from the hair roots  63  in the direction of movement  66 . In doing so, the hair strand  64  being styled is first heated at the heating zone  21 , styled, and thereafter slides over the cooling zone  24  of the cooling portion  10 , with the curl produced between the heating portion and the clip becoming “frozen” due to the temperature difference according to the present invention between the heating portion  8  and the cooling portion  10 .