Hair Curler

Abstract

A hair curler (1) includes a base body (2) including a center portion (3) being designed and arranged to support hair to be wound up. The hair curler (1) includes a first thermochromic substance (20) being designed and arranged to indicate a first temperature during a temperature increase of the hair curler (1) within a first temperature range by a first color change. The hair curler (1) includes a second thermochromic substance (35) being designed and arranged to indicate a lower second temperature during a temperature decrease of the hair curler (1) within a lower second temperature range by a second color change.

Description

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims priority to co-pending German Patent Application No. DE 10 2008 007 539.6 entitled “Lockenwickler und seine Verwendung”, filed Feb. 5, 2008.

FIELD OF THE INVENTION

The present invention generally relates to a hair curler including a base body including a center portion being designed and arranged for winding up human hair to attain curls. More particularly, the present invention relates to a hair curler including thermochromic substances for indicating temperatures by a color change.

BACKGROUND OF THE INVENTION

A hair curler is known from German Patent Application No. DE 198 43 800 A1. The known hair curler includes a base body preferably being made of plastic and being surrounded by a cover made of plastic foam. The cover made of plastic foam may include a thermochromic substance which indicates a temperature by a color change during a temperature increase.

Hair curlers of various shapes and designs are also known from German Patent Application No. DE 102 41 772 A1 corresponding to US Patent Application No. US 2004/0045573 A1, German Patent Application No. DE 199 18 742 A1 corresponding to US Patent Application No. US 200210129830 A1 and German Patent Application No. DE 37 13 280 A1. These hair curlers do not include a thermochromic substance.

SUMMARY OF THE INVENTION

The present invention relates to a hair curler for winding up human hair. The hair curler includes a base body including a center portion being designed and arranged to support hair to be wound up. The hair curler includes a first thermochromic substance being designed and arranged to indicate a first temperature during a temperature increase of the hair curler within a first temperature range by a first color change. The hair curler includes a second thermochromic substance being designed and arranged to indicate a lower second temperature during a temperature decrease of the hair curler within a lower second temperature range by a second color change.

The novel hair curler allows the user of the hair curler to easily make the correct decision when to stop blow-drying and how long to keep the hair curler in place before removing it. The novel hair curler is especially suitable for use at home. However, the novel hair curler may also be used by professionals in hairdresser's shops.

A problem during use of known hair curlers is the determination of the period of time during which the hair curler needs to be kept in place at the head after having wound up the hair. Usually, the next step after winding up is blow-drying taking place over a certain period of time and under a temperature increase of the wound up hair and of the hair curler. This step serves to ensure stability of the curl. It is known that hair is deformable in its warm condition whereas this is not the case in its cold condition. Usually, a cooling down period follows blow-drying. Cooling down is to be understood as a period of time during which the hair curler simply stays in place at the head until it reaches the desired cooler temperature. After the hair has cooled down, the unwinding process begins to attain permanently deformed curls of the desired shape. If the unwinding process is started too early, there is the danger of the shape of the curls being destroyed and being negatively influenced, respectively.

The novel hair curler includes a base body or a different portion including a first thermochromic substance and a second thermochromic substance. These thermochromic substances may be incorporated in the material of the base body such that the entire base body includes the thermochromic substances. However, it is also possible to only apply the thermochromic substances to a part of the base body. It is even possible to use the thermochromic substances at an element of the hair curler other than the base body, for example at a contact strip surrounding the base body or at a transverse pin serving to fix the base body to the head. The thermochromic substances may also be designed as coatings being applied to at least a part of the base body or to a different part of the hair curler. This especially applies if the material of the base body or of the different part of the hair curler is a comparatively hard plastic material or even metal. The thermochromic substances preferably are located at a part of the base body or of a different part of the hair curler which can be easily seen with the eye after having wound up hair. Consequently, especially the end portions of the base body are suitable for this purpose since these are the portions which are not covered by hair, but by which the hair curler is handled after having wound up the hair. It is also sufficient if only one of these end portions is covered with the thermochromic substances and the thermochromic plastic materials, respectively. It is also possible to arrange the first thermochromic substance in a first end portion of the hair curler and to arrange the second thermochromic substance in the second end portion of the hair curler. In this way, one end portion indicates the desired temperature during blow-drying, and the other end portion indicates the desired temperature during cooling down of the hair. The end portions may be designated in this way for easier handling by the user, for example by an inscription or a label.

The choice of the specific thermochromic substances depends on the temperature and the temperature range, respectively, during which the occurring color changes are desired. It is to be understood that these substances mostly change their color within a certain temperature range and not exactly at a specific temperature in a “digital” way. For example, during heating of the hair curler during blow-drying, it makes sense to choose the first thermochromic substance such that the color change occurs within a temperature range of the curl and of the hair curler, respectively, of approximately between 40° C. to 60° C. This temperature range usually corresponds to a blow-drying time of 2 to 3 minutes. In other words, it is common that approximately 50° C. are reached at the hair curler after 2 to 3 minutes. It is to be understood that this depends on the intensity of blow-drying, for example on the distance between the blow-dryer to the hair. However, the desired temperature range is often attained after approximately 2 to 3 minutes of blow-drying resulting in stabilizing and fixing the curl of wound hair.

The first color change is used during a temperature increase to indicate when the temperature has been reached at which it makes sense to stop blow-drying to prevent temperatures which are too high and which possibly result in damages of the hair. In contrast thereto, the second thermochromic substance causing the second color change becomes effective during a temperature decrease as it makes sense to indicate a lower temperature at the ending of the period of time during which the hair cools down. Usually, it is desired to attain cooling down times of approximately between 12 to 20 minutes during which the hair and the hair curler reach approximately room temperature or preferably a temperature slightly above room temperature, especially a temperature between 20° C. and 30° C., and preferably a temperature approximately between 24° C. and 27° C.

The first thermochromic plastic is added to improve handling of blow-drying. The second thermochromic plastic is used to improve handing during cooling down. In this way, the ending of both processes is clearly indicated to the user by and color change easily visible with the eye.

The base body may include approximately between 2% to 6%, especially approximately 4%, of each of the two thermochromic plastic materials. For example, the thermochromic plastic materials may be mixed with the base material of the base body.

Suitable materials for producing the base body are plastic materials such as polypropylene, polyethylene, polystyrene, acrylic styrene, polyvinyl chloride, polyamide, polyethylene terephthalate, and the like. These materials may be used for base bodies being produced by injection molding as well as for base bodies being made of a respective plastic foam. The plastic foams may be especially polyethylene foam, ethylene vinyl acetate foam, polyurethane foam, polyether amide block copolymer foam, polyester amide block copolymer foam and polyether foam. Especially, materials including approximately 92% of polypropylene and 8% of thermochromic substances have shown positive results. Especially, the thermochromic substances may be made of approximately 82% of polypropylene and approximately 18% of microencapsulated thermochromic substances. The thermochromic substances may also be polyethylene, polypropylene, polystyrene, and the like.

Other features and advantages of the present invention will become apparent to one with skill in the art upon examination of the following drawings and the detailed description. It is intended that all such additional features and advantages be included herein within the scope of the present invention, as defined by the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention can be better understood with reference to the following drawings. The components in the drawings are not necessarily to scale, emphasis instead being placed upon clearly illustrating the principles of the present invention. In the drawings, like reference numerals designate corresponding parts throughout the several views.

FIG. 1 is a perspective view of a first exemplary embodiment of the novel hair curler.

FIG. 2 is a sectional view through the hair curler according to FIG. 1 in its winding end position close to the scalp of a human head.

FIG. 3 is a sectional view through a second exemplary embodiment of the novel hair curler including three interconnected elements.

FIG. 4 is a perspective view of a third exemplary embodiment of the novel hair curler.

FIG. 5 is a sectional view through a fourth exemplary embodiment of the novel hair curler.

FIG. 6 is a sectional view along line VI-VI in FIG. 5.

FIG. 7 is a sectional view along line VII-VII in FIG. 5.

FIG. 8 is a side view of a fifth exemplary embodiment of the novel hair curler.

FIG. 9 is a view of the hair curler according to FIG. 8 with a wound up curl and bent end portions.

DETAILED DESCRIPTION

Referring now in greater detail to the drawings, FIG. 1 illustrates a first exemplary embodiment of the novel hair curler 1. The hair curler 1 includes a base body 2 being designed as a form body made of plastic, metal, and the like. Preferably, the base body 2 is designed to be hollow. As seen in an axial direction, the base body 2 includes a center portion 3 and two fixing portions 4 being arranged at its ends. The two fixing portions 4 have the same diameter being greater than the diameter of the center portion 3. In this way, the hair curler 1 has the shape of a coil or a roller with end portions extending in a radial outer direction. Preferably, the entire axial extension of the circumference of the fixing portions 4 is covered by a hook band 5. Such hook bands 5 are known as parts of Velcros. They include a woven or seemed portion including outwardly protruding spikes or hooks 6. Especially, the hooks 6 may be designed as loops which have been opened by cutting. The center portion 3 and also the fixing portions 4 at the base body 2 may include a multitude of openings 7.

FIG. 2 illustrates the wound up position of the hair curler 1 at a human head 8 in the region of the scalp 9. The hair at the scalp 8 is not illustrated. Only one wound up part of hair is schematically illustrated, the part being wound up to attain a curl 10. It is to be understood that the winding operation of such a curl 10 begins at the tips of the hair. A portion of a spike band 11 is located in the region of the center portion 3. The spikes of the spike band 11 are designed to be shorter in a radial direction compared to the hooks 6 of the hook band 7 being located in each one of the fixing portions 4. The spike band 11 only extends over a certain portion of the axial length of the center portion 3. It serves to fixedly arrange the tips of the hair in that portion and to begin the winding process. Due to the increase of the diameter of the center portion 3 compared to the two fixing portions 4, it is ensured that the curl 10 being attained from winding up the hair is only arranged in the center portion 3, and it attains a certain winding thickness in this portion. During winding, the hook band in both fixing portions 4 remains free from hair. As soon as the hair curler 1 approaches the scalp 9 during winding and the winding process is completed, the hair curler 1 is pressed against the scalp 9. This position is illustrated in FIG. 2. The hooks 6 of the two hook bands 5 of the two fixing portions 4 engage the hair at the hair line close to the scalp 9 such that the hair curler 1 attains its predetermined fixed position close to the scalp 9. Due to the increase of the diameter of the smaller diameter of the center portion 3 compared to the greater diameter of the fixing portions 4, one attains room for a certain winding thickness of the curl 10. Despite this fact, due to the increased diameter of the fixing portions 4, there is the possibility of maintaining the fixed position at the head 8 even when this has a round design in many portions. The wound up hair forming the curl 10 at the hair line are not bent, but they can instead extend between the root of the hair and the winding location at the circumference of the curl 10 in a radial position with respect to the head 8 having a positive influence on the full design of the curl 10. However, even in this winding end position, there still is a free space allowing for passage of air such that the portion of the curl 10 facing the scalp 9 can also be aerated and dried after having wound up the hair in their wet condition.

The hair curler 1 according to FIG. 2 may especially have the following dimensions. The center portion may have a diameter of approximately between 12 mm and 32 mm. The center portion 3 may especially extend over an axial length of approximately between 13 mm and 40 mm. The two fixing portions 4 may especially have a diameter 14 of approximately 40 mm, and they may have an axial length 15 of approximately 10 mm. The hooks 6 may have a length of approximately 3 mm in a radial direction. The spikes of the spike band 11 may have a length of approximately 1.5 mm.

The base body 2 of the exemplary embodiment of the novel hair curler 1 according to FIG. 2 is designed as a one piece form body. Only the two sections of the hook band 5 and the spike band 11 are separate pieces being connected to the base body 2 by welding in the sense of simultaneously interconnecting the two ends of each band section.

FIG. 3 illustrates an exemplary embodiment of the novel hair curler 1 having a smaller size and serving for winding up a shorter portion of hair on a smaller diameter. The hair curler 1 includes three elements. The base body 2 is formed by a tube section 16 continuously extending over the axial length of the hair curler 1 and two rings 17 being connected to the tube section 16. The connection may be realized by gluing or by a snap fit. The rings 17 then form the fixing portions 4, and they realize the increase of the diameter compared to the center portion 3. The center portion 3 may include a ribbing 18 to simplify connection of the hair at the beginning of the winding process. There also is the possibility of arranging sections of hook bands 5 or hooks 6 directly on the rings 17. The ratio of the diameters and of the lengths is chosen to differ from the above described embodiment. The hair curler 1 has a comparatively small size. The increase of the diameter is also smaller compared to the embodiment of the hair curler 1 illustrated in FIG. 2.

The base body 2 of the hair curl 1 is made of a material 19. Preferably, the material 19 is plastic. Suitable kinds of plastic are polypropylene, polyethylene, polystyrene, acrylic styrene, polyvinyl chloride, polyamide, polyethylene terephthalate, and the like, or a respective plastic foam. The material 19 forming the base body 2 may be mixed with a first thermochromic substance 20 and/or a second thermochromic substance 35. It is possible that the entire base body 2 of the hair curler 1 according to FIG. 1 or only a part thereof is made of this material 19.

In the exemplary embodiment of the hair curler 1 according to FIG. 2, a plastic material is used in the region of the hook band 5 and/or in the region of the hooks 6, the material corresponding to the material 19 of the base body 2, but including a first thermochromic plastic material 21 and a second thermochromic plastic material 36. It is also possible to use a coating of such thermochromic plastic materials 21, 36 at this place. The exemplary embodiment of the hair curler 1 illustrated in FIG. 2 shows that the thermochromic plastic materials 21, 36 may also be located at a different portion of the hair curler 1 other than the base body 2.

In the exemplary embodiment of the novel hair curler 1 according to FIG. 3, the rings 17 may be made of a material to which the thermochromic plastic materials 21, 36 have been added. It is also possible to only cover the rings 17 with such materials on the outer side.

FIGS. 4 to 7 illustrate another exemplary embodiment of the novel hair curler 1. The hair curler 1 also includes a base body 2. In this case, the base body 2 has a conical shape and a shape of a truncated cone, respectively. The hair curler 1 and the base body 2, respectively, extend over their length from a beginning end 22 to the other end 23. The beginning end 22 is designated as the end having the greater cross-section. As it is already to be seen in FIG. 4, the base body 2 and thus the hair curler 1 at its beginning end 22 has an oval cross-section being comparatively great and continuously diminishing towards its other end 23. Especially, the base body 2 may be designed as a hollow body. It may be made of plastic or metal and it usually has sufficient stability and stiffness. The base body 2 may be designed to include openings similar to a grate along its entire length, or it may include circular openings 7, for example. The base body 2 and the hair curler 1, respectively, in the region of its other end 23 include an enlarged portion 24. In the illustrated example, the enlarged portion 24 is designed as a spherical protrusion. The enlarged portion 24 may be designed as one piece with the base body 2 by injection molding. The enlarged portion 24 has a greater diameter than the base body 2 in the region of its other end 23. The enlarged portion 24 fulfills two functions. It prevents hair from slipping down during winding or afterwards. On the other hand, the enlarged portion 24 of the hair curler 1 simplifies handling of the hair curler 1 to simplify winding of hair.

On the outer circumference of the base body 2, especially beginning at its beginning end 22, and extending over a certain length of the base body 2, a section of a hook band 5 is arranged and fixed. The hook band 5 has a design as it is known from Velcros, for example. The hook band 5 includes separate hooks 6 extending approximately in a radial direction or spikes having a mushroom shape at its circumference. The strip of hook band 5 in the exemplary embodiment of the hair curler 1 illustrated in FIG. 4 approximately has half the length of the axial length of the hair curler 1 and of the base body 2, respectively. However, it is also possible to design the hook band 5 to be shorter or longer.

A fixing unit 25 is associated with the hair curler 1. In the illustrated exemplary case, the fixing unit 25 includes a needle 26 being designed and arranged to be inserted through a respective opening 7 in the base body 2 in a transverse direction when the winding process of the hair has been completed.

Possible designs of the cross-section of the hair curler 1 in accordance with the exemplary embodiment of FIG. 4 are illustrated in FIGS. 5 to 7.

The base body 2 illustrated in FIGS. 4 to 7 is also completely or partly made of thermochromic plastic materials 21, 36. Instead or additionally, it is also possible to arrange the thermochromic plastic materials 21, 36 in the region of the enlarged portion 24 or even only in the region of the needle 26, meaning at such locations which can be freely seen by the user when hair is wound up on the hair curler 1 to allow for seeing the color change during hair drying or after cooling of the hair.

The exemplary embodiment of the novel hair curler 1 illustrated in FIGS. 8 and 9 includes a base body 2 being made of resilient plastic foam having a certain degree of restoring properties. The base body 2 has a bar-like, elongated shape and a cross-section which is either circular or approximately square along its entire length. The base body 2 has a surface which may be designed to be open-pored and rough such that the hair to be wound engage this surface and are captured by this surface. A flexible wire mesh 27 is located inside of the base body 2, meaning a piece of flexible wire which can be permanently deformed. The two ends 28 of the wire mesh 27 are bent or deformed similar to a hook to reduce the risk of injuries. The wire mesh 27 in its middle portion may be surrounded by a tube section 29 by which the wire mesh 27 is enforced. When supplying forces in a normal range, the middle portion of the wire mesh 27 cannot be bent, whereas the end portions 30 are flexible. In this way, the base body 2 has a stiff center section 31 not being flexible and end sections 32 being flexible. The plastic foam material of the base body 2 continuously extends over the length such that the differences of the flexibility only result from the wire mesh 27. However, it is also possible not to arrange the tube section 29 such that the base body 2 has a generally bent shape. A portion of hair 33 can be rolled in the center section 31 of the hair curler 1 to attain a curl.

In the exemplary embodiment of the novel hair curler 1 illustrated in FIG. 8, the material of the plastic foam includes the first thermochromic substance 20, especially the thermochromic plastic 21, and the second thermochromic substance 35, especially the thermochromic plastic 36.

Alternatively or additionally, the surface of the base body 2 may include a coating 34 including these substances 20, 35, or these substances 20, 35 may be arranged in the region of the end portions 32.

These thermochromic substances 20, 35 may also be used in cases when the base body 2 or a different element of the hair curler 1 is not made of plastic, but instead of metal, for example, especially when it is made in the form of a wire grate and the like.

The following applies to all illustrated exemplary embodiments as well as additional embodiments of the novel hair curler. The material 19 of the base body 2 or of a different portion of the hair curler 1 may be plastic, especially plastic produced by injection molding. The plastic may also be applied as plastic foam, especially as illustrated in the embodiments of FIGS. 8 and 9. The plastic may be polypropylene, polyethylene, polystyrene, acrylic styrene, polyvinyl chloride, polyamide, polyethylene terephthalate, and the like. The plastic may also be used in the shape of foam.

The first thermochromic substance 20 may be especially a thermochromic plastic 21. The second thermochromic substance 35 may be especially a thermochromic plastic 36. Preferably, the thermochromic substances 20, 35 only form a part of the material, or they are applied in the form of a coating 34. It is also possible to use such a coating 34 on a needle 26 of the fixing unit 25, for example.

Many variations and modifications may be made to the preferred embodiments of the invention without departing substantially from the spirit and principles of the invention. All such modifications and variations are intended to be included herein within the scope of the present invention, as defined by the following claims.

Claims

1. A hair curler for winding up human hair, comprising:

a base body, said base body including a center portion being designed and arranged to support hair to be wound up;

a first thermochromic substance, said first thermochromic substance being designed and arranged to indicate a first temperature during a temperature increase of said hair curler within a first temperature range by a first color change; and

a second thermochromic substance, said second thermochromic substance being designed and arranged to indicate a lower second temperature during a temperature decrease of said hair curler within a lower second temperature range by a second color change.

2. The hair curler of claim 1, wherein said base body is made of plastic and said first thermochromic substance is a first thermochromic plastic and said second thermochromic substance is a second thermochromic plastic.

3. The hair curler of claim 2, wherein said first thermochromic plastic and said second thermochromic plastic are mixed with said plastic of said base body.

4. The hair curler of claim 2, wherein said first thermochromic plastic is a material indicating the first temperature by the first color change after blow-drying the hair for approximately 2 to 3 minutes.

5. The hair curler of claim 2, wherein said second thermochromic plastic is a material indicating the lower second temperature after cooling down for approximately 12 to 20 minutes after blow-drying the hair.

6. The hair curler of claim 5, wherein said second thermochromic plastic is a material indicating the lower second temperature after cooling down for approximately 12 to 20 minutes after blow-drying the hair.

7. The hair curler of claim 1, wherein said base body is made of a material including approximately between 2% and 6% of said first thermochromic substance and approximately between 2% and 6% of said second thermochromic substance.

8. The hair curler of claim 2, wherein said first thermochromic plastic and said second thermochromic plastic are mixed with the plastic of a part of said hair curler other than said base body.

9. The hair curler of claim 2, wherein said first thermochromic plastic and said second thermochromic plastic are designed as at least one coating of said base body.

10. The hair curler of claim 2, wherein said first thermochromic plastic and said second thermochromic plastic are designed as at least one coating of a part of said hair curler other than said base body.

11. The hair curler of claim 2, wherein said base body is made of at least one plastic material selected from the group consisting of polypropylene, polyethylene, polystyrene, acrylic styrene, polyvinyl chloride, polyamide and polyethylene terephthalate a respective plastic foam.

12. The hair curler of claim 11, wherein said base body is made plastic foam.