Abstract:
A heatable hair curling device includes a plurality of hair curlers for winding up human hair and a thermally insulating carrier for retaining the curlers and insulating the curlers from heat loss prior to individual curler use. Each curler includes an elongate casing of flexible material having opposite first and second ends attachable to each other, a body, and an axial length. A heat absorbent material is contained within the body of each curler. The thermally insulating carrier has a length and includes an interior and an exterior piece of flexible heat-safe material. The interior piece of flexible heat-safe material is attached to the exterior piece of flexible heat-safe material. A center strap is disposed along the length of the interior piece the carrier and includes a lower and an upper piece of flexible heat-safe material. A heating element is contained between the interior and exterior pieces of flexible heat-safe material of the carrier and between the lower and upper pieces of flexible heat-safe material of the center strap.

Description:
CROSS-REFERENCE TO RELATED APPLICATION(S) 
   This application is related to and a continuation-in-part of the application Ser. No. 10/458,757, filed on Jun. 10, 2003, and entitled “Microwavable Hair Curling Device”, now U.S. Pat. No. 7,017,590 B2, which is herein incorporated by reference. 

   BACKGROUND OF THE INVENTION 
   The present invention relates to a hair curling device. In particular, the present invention relates to a heatable hair curling device that is effective, yet easy, safe, and time-efficient to use. 
   Numerous hair curling devices have been introduced over the years. Hair curling devices come in a variety of configurations, sizes, and materials. It is well known that the most efficient way to curl hair is with thermal energy. Hair can be curled in the absence of heat if the hair is wrapped around the curling device when it is wet and allowed to dry into a curl. However, waiting for hair to air dry takes a long time, making it inconvenient in today&#39;s fast paced world. In addition, rollers can be uncomfortable to wear, especially for long periods of time while waiting for hair to dry. 
   Most of the prior art hair curling devices employ an electrical heating means. A curling iron, while effective at curling hair quickly, gets extremely hot and can burn the hair and blister the skin, making it dangerous for the elderly and the young to use. In addition, a curling iron takes a long time to heat, possibly exposes the user to electric shock, and limits the user&#39;s movement to the range of the electric cord. Hot rollers, while they do not readily burn the skin or limit movement, are very hot to the touch and therefore hard to handle. In addition, hot rollers are heavy and have a tendency to fall out of the hair. 
   Microwave energy has also been used as a means for heating hair curling devices. U.S. Pat. Nos. 6,064,051, 6,079,422, 5,988,182, and 6,352,080 provide curlers which may be heated directly in the microwave. The known curlers contain a microwave heatable material which transfers energy from the curler to the hair, causing the hair to curl. The curlers hold the hair in place with pins, clips, ties, surface protrusions, or combs. In these cases, individual curlers are heated one at a time, immediately before being placed in the hair. If not placed immediately in the hair after being heated, the heat will dissipate from the curlers into the atmosphere. Also, the process of clipping, tying, or pinning the curler in place is cumbersome if being done by one person. This makes the process of heating and setting hair especially time consuming. Another problem with prior art microwavable hair curlers is that they can be easily lost or misplaced. 
   It is well known in the art of cosmetology that curling hair at higher temperatures results in longer lasting curls. Unfortunately, heat is also known in the art to dry hair out, eventually causing split ends and breakages. In addition, heat can be dangerous to the skin. Thus, there continues to be a need for a hair curling device whose use of heat does not dry out the hair, is warm (not hot) to the touch, is capable of withstanding high temperatures without melting or scorching, and is simple to wrap hair around and hold in place. The cylindrical roller shape of most prior art curlers gives the hair rigid, symmetrical, and ultimately unnatural looking curls. None of the prior art hair curling devices have been satisfactory. Thus, there exists a need for a hair curling system which is effective at curling, gentle on the hair, easy, safe, time-efficient, and capable of producing relaxed and natural looking curls. 
   BRIEF SUMMARY OF THE INVENTION 
   A heatable hair curling device of the present invention includes a plurality of hair curlers for winding up human hair and a thermally insulating carrier for retaining the curlers and insulating the curlers from heat loss prior to individual curler use. Each curler includes an elongate casing of flexible material having opposite first and second ends attachable to each other, a body, and an axial length. A heat absorbent material is contained within the body of each curler. The thermally insulating carrier has a length and includes an interior and an exterior piece of flexible heat-safe material. The interior piece of flexible heat-safe material is attached to the exterior piece of flexible heat-safe material. A center strap is disposed along the length of the interior piece the carrier and includes a lower and an upper piece of flexible heat-safe material. A heating element is contained between the interior and exterior pieces of flexible heat-safe material of the carrier and between the lower and upper pieces of flexible heat-safe material of the center strap. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a perspective view of a first embodiment of a hair curling device of the present invention in a fully rolled configuration. 
       FIG. 2  is a perspective view of the first embodiment of the hair curling device of the present invention in a fully unrolled configuration exposing a set of hair curlers. 
       FIG. 3  is a perspective view of the first embodiment of the hair curling device of the present invention in a partially unrolled configuration. 
       FIG. 4  is a perspective view of a second embodiment of the hair curling device of the present invention in a fully folded configuration. 
       FIG. 5A  is a side view of one embodiment of a hair curler of the present invention. 
       FIG. 5B  is a perspective view of a section of the hair curler of  FIG. 3A . 
       FIG. 6  is a perspective view of the first embodiment of the hair curling device of the present invention in a partially unrolled configuration exposing a set of hair curlers. 
       FIG. 7  is a perspective view showing the second embodiment of the hair curling device of the present invention in a partially unfolded configuration. 
       FIG. 8  is a perspective view showing the second embodiment of the hair curling device of the present invention in a partially unfolded configuration. 
       FIG. 9  is a perspective view showing the second embodiment of the hair curling device of the present invention in a partially unfolded configuration. 
       FIG. 10  is a rear view of a hair curler of the present invention placed in a section of hair. 
       FIG. 11A  shows the hair curler placed near the end of a section of hair to be curled. 
       FIG. 11B  shows the section of hair being wrapped around the hair curler of  FIG. 10A . 
       FIG. 11C  shows the ends of the hair curler fastened together after the section of hair has been fully wrapped around the hair curler. 
   

   DETAILED DESCRIPTION 
     FIG. 1  is a perspective view of a first embodiment of hair curling device  10 . Hair curling device  10  consists of a carrier  12  and a set of hair curlers  14  (shown in detail in  FIG. 2 ). Carrier  12  includes a thermal insulating blanket  16  which, as shown in  FIG. 1 , may be rolled into a cylindrical shape. Blanket  16  has an exterior surface  18  and an interior surface  20  (shown in detail in  FIG. 2 ) made of fire retardant fabric. Straps  22  and  24  are attached on exterior surface  18  of blanket  16 . Free ends  22   a  and  22   b  of strap  22  are tied together and free ends  24   a  and  24   b  of strap  24  are tied together to hold carrier  12  in its fully rolled cylindrical shape. Devices other than straps  22  and  24  can be used to hold carrier  12  in its cylindrical shape so long as the device is fire retardant. Other embodiments of carrier  12  can be used as well. For example, blanket  16  may be simply folded so that it forms a flat carrier instead of a cylinder. 
   Surfaces  18  and  20  and straps  22  and  24  of blanket  16  are made of a fire-retardant fabric that is lightweight, flexible, machine washable and capable of withstanding temperatures of at least about 250° F. without scorching or melting. Preferably, blanket  16  is made out of fabrics with fire-retardant properties such as NOMEX®, NOVEON®, MILLENIA™, KOTHMEX™ or KYNOL™ brand materials. Blanket  16  preferably is capable of withstanding temperatures of at least about 600° F. 
     FIG. 2  shows carrier  12  after thermal blanket  16  is fully unrolled. When blanket  16  is fully unrolled, carrier  12  reveals interior surface  20 , center strap  26  and set of hair curlers  14 . Center strap  26  runs lengthwise down interior surface  20  of blanket  16 . Hair curlers  14  are held in place under center strap  26 . Curlers  14  will be discussed in more detail with reference to  FIGS. 5A and 5B . 
   Interior surface  20  of blanket  16  is rectangular in shape having the following features: opposite first and second ends  28  and  30 , opposite first and second side edges  32  and  34 , length L, roll axis RA, width W, and seam  36 . To reveal interior surface  20 , blanket  16  is unrolled from first end  28  to second end  30  about roll axis RA. When fully unrolled, interior surface  20  is about twenty-nine inches long along length L. Interior surface  20  is about eight inches wide along width W when measured between side edges  32  and  34 . First and second ends  28  and  30  run transverse to side edges  32  and  34 . Interior surface  20  and exterior surface  18  (see  FIG. 1 ) are stitched together at seam  36 . 
   Center strap  26  is comprised of an interior piece  38  and an exterior piece  40  and is attached to interior surface  20  of blanket  16  at the following five attachment points:  42 ,  44 ,  46 ,  48 , and  50 ; however, different embodiments of the present invention may differ in the number of attachment points, so long as at least one curler  14  is able to fit in between them. In  FIG. 2 , fifteen hair curlers  14  are secured under center strap  26  in between the aforementioned attachment points  42 ,  44 ,  46 ,  48 , and  50 . When placed under strap  26 , curlers  14  are lined up side-by-side so that they are parallel to first and second ends  28  and  30  of interior surface  20 . Center strap  26  is preferably made of the same fire-retardant material as blanket  16 . The fabric is lightweight, flexible, machine washable and capable of withstanding temperatures of at least about 250° F. 
   Preferably, center strap  26  is made out of fabrics with fire retardant properties such as NOMEX®, NOVEON®, MILLENIA™, KOTHMEX™ or KYNOL™ brand materials. Hair curlers  14  may be held in place by devices other than center strap  26  so long as the device is fire-retardant, flexible, machine washable, and capable of holding curlers  14  side-by-side along interior surface  20 . 
   Attachment points  42 ,  44 ,  46 ,  48 , and  50  of center strap  26  keep curlers  14  organized so that thermal blanket  16  may be easily rolled into a cylindrical shape without curlers  14  falling out and becoming lost or misplaced. Carrier  12 , complete with interior and exterior surfaces  20  and  18  of thermal blanket  16 , center strap  26 , and exterior straps  22  and  24 , is designed to be fire-retardant, lightweight and machine washable. In addition, thermal blanket  16  is easy to roll and unroll, safe to use, easy to transport and an excellent place to store curlers in between uses. 
   Heating element  52  is housed between exterior and interior surfaces  18  and  20  of blanket  16  and between interior and exterior pieces  38  and  40  of center strap  26 . Heating element  52  is shown in phantom within center strap  26  and is a resistance-type heating element similar to those used in electric heating pads and blankets. Heating element  52  is sewn inside carrier  12  and is capable of obtaining temperatures of at least about 275° F. In order for heating element  52  to operate, power cord  54  operatively connects heating element  52  to a power source. Control box  56  is either located in, or connected to, power cord  54  and controls the level of power supplied from the power source to heating element  52 . The user can thus control the temperature of heating element  52  through control box  56 . 
     FIG. 3  is a perspective view of a second embodiment of hair curling device  100 . In the second embodiment of hair curling device  100 , carrier  102  includes a heating and thermal insulating blanket  104  folded to form a flat carrier. Carrier  102  is held in its fully folded configuration by free end  106   a  of strap  106  and free end  108   a  of strap  108 . 
     FIG. 4  shows carrier  102  after blanket  104  is fully unfolded. When blanket  104  is fully unfolded, carrier  102  reveals interior surface  110 , a first foldable extension  112 , a center foldable extension  114 , a second foldable extension  116 , center strap  118 , heating element  26  (shown in phantom), and hair curlers  14 . Interior surface  110  of blanket  104  is rectangular in shape having the following features: first portion  120 , center portion  122 , second portion  124 , length L, first fold axis  126   a  and second fold axis  126   b , width W, and seam  128 . First foldable extension  112  is attached to first portion  120  of blanket  104  at first side edge  130 , center foldable extension  114  is attached to center portion  122  of blanket  104  at first side edge  130 , and second foldable extension  116  is attached to second portion  124  of blanket  101  at first side edge  130 . Foldable extensions  112 ,  114 , and  116  have the same width W as interior surface  110  of blanket  104 . 
   To open hair curling device  100  from the fully folded configuration shown in  FIG. 3  to the fully unfolded configuration shown in  FIG. 4 , first portion  120  of blanket  104  is unfolded from center portion  122  about fold axis  126   a . Second portion  124  of blanket  104  is then unfolded from center portion  122  about fold axis  126   b . First foldable extension  112  is unfolded from first portion  120  at first side edge  130 , center foldable extension  114  is unfolded from center portion  122  at first side edge  130 , and second foldable extension  116  is unfolded from second portion  124  at first side edge  130 . 
     FIG. 5A  shows one embodiment of hair curler  14 . Hair curler  14  comprises the following features: outer casing  200 , axial curler length  202 , body  204 , opposite first and second ends  206  and  208 , first and second seams  210  and  212 , first fastener  214 , and second fastener  216  (shown in detail in  FIG. 5B ). Hair curler  14  is shaped like a rod and is about 7.5 inches long when measured along axial length  202  and about 1.25 inches wide. Both first end  206  and second end  208  are flat in order to accommodate the placement of first and second fasteners  214  and  216 . First and second ends  206  and  208  each measure about 2.25 inches long and 1.25 inches wide. Body  204  of curler  14  is not flat and has a total circumference of about 2.5 inches when measured around its center. First and second seams  210  and  212  separate body  204  of curler  14  from flat ends  206  and  208 . Body  204  of curler  14  measures about 3.5 inches along axial curler length  202  between first and second seams  210  and  212 . Outer casing  200  of hair curler  14  is made out of fire-retardant fabric that is lightweight, flexible, machine washable, and capable of withstanding temperatures of at least about 250° F. Preferably, outer casing  70  is made out of fabric with fire-retardant properties such as NOMEX®, NOVEON®, MILLENIA™, KOTHMEX™ or KYNOL™ brand materials. 
   Fasteners  214  and  216  are preferably made of hook and loop material, capable of withstanding temperatures of at least about 250° F. First fastener  214  is disposed on the top of first end  206  while second fastener  216  is disposed on the bottom of second end  208 . First fastener  214  is preferably composed of tiny loops  218  while second fastener  216  is composed of tiny hooks  220 . Seams  210  and  212  protect ends  206  and  208  of curler  14  from getting too hot and damaging fasteners  214  and  216 . The hook and loop fastening device used in this embodiment may be replaced by other machine washable, fire-retardant fastening devices so long as both ends  206  and  208  of curler  14  are capable of fastening together and the fastener does not melt or scorch under heat. 
     FIG. 5B  is a perspective view of a section of hair curler  14  of  FIG. 5A . The cross-section of hair curler  14  shows the following components: outer casing  200 , axial curler length  202 , body  204 , first and second ends  206  and  208 , first and second seams  210  and  212 , first and second fasteners  214  and  216 , interior cavity  222 , and heat absorbent material  224 . Outer casing  200  is the outermost layer of curler  14  and covers the entire curler  14 . Interior cavity  222  forms the inside of body  204 . Interior cavity  222  is filled with heat absorbent material  224 , preferably in the form of silica beads or other desiccant material. 
   Heat absorbent material  224  fills interior cavity  222  of hair curler  14 . Heat absorbent material  224  includes, but is not limited to, silica beads, buckwheat, flax seed, thermal gel, and any other desiccant material capable of releasing moisture when heated. In one embodiment, heat absorbent material  224  is in the form of silica beads, specifically 99.5% SiO 2 ; 0.021% Na 2 O; 0.02% Fe 2 O 3 ; 0.01% MgO; 0.04% Ca; 0.16% A 12 O 3 , and 0.01% other compounds (all percentages given are weight percentages). The grain size of each silica bead can vary from about 0.5 to 5.0 mm in diameter. 
   Silica beads are preferably used as heat absorbent material  224  because as a desiccant they adsorb moisture at room temperature and release moisture upon being heated to temperatures of approximately 250° F. to 350° F. When using the preferred embodiment of the present invention, post-heated silica beads release moisture and heat through outer casing  200  of hair curler  14  into the hair shaft. Thus, hair curler  14 , when used according to the present invention, both moisturizes and curls hair at the same time. Once the hair cools, which takes about five minutes, the curls are set and the curlers may be removed. 
   Hygiene is important in personal care, especially if several people in a family are using the same styling tool. Styling products, such as hair spray and gel, can build up on hair curling tools. The build-up of old styling product on hair curling tools is unhygienic and not good for styling performance reasons. Fire-retardant fabric and silica, as used in the present invention, are machine washable and make curling hair with the present invention more sanitary than conventional methods. In addition, fabric is gentle on the hair, unlike bristles, plastic, and metal styling tools. Because outer casing  200  of curler  14  is made of soft fabric and the shape of curler  14  is not cylindrical, each curl produced by the present invention is unique—unlike curls produced by roller cylinders of consistent form and uniform shape. 
     FIG. 6  is a perspective view of carrier  12  being used according to the first embodiment of the present invention.  FIG. 6  shows the following features: blanket  16 , strap  22  and its free end  22   a , strap  24  and its free end  24   a , exterior surface  18 , interior surface  20 , and center strap  26 . 
   To use hair curling device  10 , carrier  12  is heated in its fully rolled configuration (as shown in  FIG. 1 ). Carrier  12  is connected to a power source by power cord  54 , switched on by control box  56 , and heated by heating element  52 . Because curlers  14  are embedded in carrier  12  when carrier  12  is in the fully rolled configuration and heated, as heating element  52  reach temperatures of about 275° F., heat absorbent material  224  of curlers  14  are also heated. When carrier  12  is heated to the desired temperature, free ends  22   a  and  24   a  are untied and carrier  12  is preferably unrolled so that only one curler  14  is exposed at a time. Remaining curlers  14  remain inside carrier  12  where they stay warm while awaiting use. 
     FIGS. 7 ,  8 , and  9  are perspective views of carrier  102  being used according to the second embodiment of the present invention showing how carrier  102  is unfolded to reveal only one group of curlers  14  at a time.  FIG. 8  shows one group of curlers  14  held in place against interior surface  110  under center strap  118  after first foldable extension  112  is unfolded along first side edge  130  of blanket  104 . Remaining curlers  14  remain inside the folded portions of carrier  102  where they stay warm while awaiting use. Once all of curlers  14  currently exposed are removed from center strap  118 , second portion  124  is unfolded along fold axis  126   b  and center foldable extension  114  is unfolded along first side edge  130  to expose another set of curlers  14  as shown in  FIG. 9 . Second foldable extension  116  remains folded over first side edge  130  until curlers  14  under first and center foldable extensions  112  and  114  are used and curlers  14  under second foldable extension  116  are needed. 
   To use the present invention, human hair is first divided into sections that the user wishes to curl. Immediately after exposing a warm curler  14  as shown in  FIG. 6 , curler  14  is removed from carrier  12  and placed in the section of hair the user wishes to curl, as shown in  FIG. 10 .  FIGS. 11A through 11C  show the steps involved in using the present invention after a warm curler  14  has been removed from carrier  12 .  FIG. 11A  shows curler  14  placed at the end of a section of hair that a user wishes to curl.  FIG. 11B  shows wrapping a section of hair around outer casing  200  of curler  14 . Hair may be wrapped either over or under curler  14 , depending on the desired curl. Once a section of hair is fully wrapped around curler  14 , curler  14  is fastened together to hold the curl in place.  FIG. 11C  shows a rear view of a user securing curler  14  in place by bending curler  14  along its axial length  202  and attaching first fastener  214  (shown in  FIG. 11A ) to second fastener  216 . Because hair is wound multiple times around hair curler  14  (see  FIG. 11B  and  FIG. 11C ), curler  14  will not fall out. Curler  14  is lightweight and easy to fasten in place. For each additional section of hair a user wishes to curl, another warm curler  14  is removed from carrier  12  while remaining curlers  14  stay warm inside carrier  12 . The steps shown in  FIG. 11A  through  FIG. 11C  are repeated for each additional hair section. Once the wrapped hair cools (approximately 5 minutes), curlers  14  are removed, leaving a natural wavy curl that is easy to style. Although FIGS.  10  and  11 A- 11 C discuss using curler  14  in reference to carrier  12  of the first embodiment of hair curling device  10 , curler  14  is used with carrier  102  of the second embodiment of hair curling device  100  in the same manner. 
   The present invention provides a fast, safe, clean, and easy way to curl hair. Whereas previous hair curling devices were effective at curling hair, their intense heat dried out the user&#39;s hair and posed a risk of burning the user&#39;s skin. In addition, devices heated with electrical heat put the user at risk of electrical shock and limited the user&#39;s movement to the range of the electric cord. The present invention solves these problems by providing a hair curling device whose use of heat does not dry out the hair, is warm (not hot) to the touch, and is simple to wrap hair around and hold in place. In addition, the carrier of the present invention solves the cumbersome and time-consuming process of having to heat individual curlers in the microwave. The power cord attached to the heating elements housed in the carrier allows all the curlers to be heated together in one easy step, requires nothing more than an electrical outlet, and prevents the curlers from losing heat. The carrier also provides a place to store curlers between uses so that the curlers are not lost or misplaced. 
   Although the present invention has been described with reference to preferred embodiments, workers skilled in the art will recognize that changes may be made in form and detail without departing from the spirit and scope of the invention.