Patent Publication Number: US-2011061673-A1

Title: Adjustable-barrel curling iron

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims the priority benefit of U.S. Provisional Patent Application Ser. No. 61/241,526, filed Sep. 11, 2009, which is hereby incorporated herein by reference. 
    
    
     BACKGROUND 
     Many women use electric hair-care appliances such as hair dryers, flat irons, and curling irons to style their hair. Conventional curling irons have a heated barrel that is used to create curls in the hair. Different-sized curls are sometimes desirable to create different styles suited for an occasion, outfit, trend, preference, current hair-length, etc. To create different-sized curls, different-sized curling iron barrels must be used. Thus, in order to be able to style their hair with different-sized curls, many women have several different curling irons each with a different-sized barrel. However, many women have limited storage space for curling irons and other hair-care appliances, and arranging for sufficient storage space can be a real problem. 
     In addition, there are usually a limited number of electrical outlets available in bathrooms, where most hairstyling is done. For women who use multiple electric hair-care appliances, it&#39;s common to add plug-in outlet expansions and/or power strips. This can lead to a potential safety hazard by too much current draw interfering with GFCI operation and/or causing circuit overloads. 
     Accordingly, it can be seen that there exists a need for a better way for women to conveniently and safely create different-sized curls in their hair. It is to the provision of solutions to this and other problems that the present invention is primarily directed. 
     SUMMARY 
     The present invention relates to adjustable-barrel curling irons for curling hair into different-sized curls. In one example embodiment there is provided a curling iron comprising a handle, a pivotal clip, a barrel-adjustment assembly, and an adjustable end assembly. The barrel-adjustment assembly comprises an adjustment ring, a fixed ring, an adjustable diameter barrel, and a barrel cam, wherein the adjustment ring and the fixed ring can be manipulated to change the diameter of the barrel by wrapping the barrel upon the barrel cam. The barrel is a coiled sheet comprising a flexible heating element. The adjustable end assembly comprises a plurality of fan blades, constructed to provide coverage for the end of the barrel as the diameter of the barrel is changed. 
     In other example embodiments, adjustable-barrel curling irons are provided with adjustable heated fingers, a telescoping barrel, a swappable/invertible barrel, an extending heated coil barrel, and a woven cylinder barrel. 
     These and other aspects, features, and advantages of the invention will be understood with reference to the drawing figures and detailed description herein, and will be realized by means of the various elements and combinations particularly pointed out in the appended claims. It is to be understood that both the foregoing general description and the following brief description of the drawings and detailed description of the invention are explanatory of example embodiments of the invention, and are not restrictive of the invention, as claimed. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a first perspective view of an adjustable-barrel curling iron according to a first example embodiment of the present invention, showing an adjustable barrel in a fully expanded position. 
         FIG. 2  is a second perspective view of the adjustable-barrel curling iron of  FIG. 1 , with a portion of a flexible distal tip not shown for clarity, showing the adjustable barrel in a fully contracted position. 
         FIG. 3  is a third perspective view of the adjustable-barrel curling iron of  FIG. 1 , with the adjustable distal tip assembly not shown for clarity, showing the adjustable barrel in the fully expanded position. 
         FIG. 4  shows the adjustable-barrel curling iron of  FIG. 3  with the adjustable barrel in a partially contracted, intermediate position. 
         FIG. 5  shows the adjustable-barrel curling iron of  FIG. 3  with the adjustable barrel in the fully contracted position. 
         FIG. 6  is a right end view of the adjustable-barrel curling iron of  FIG. 3 . 
         FIG. 7  is a right end view of the adjustable-barrel curling iron of  FIG. 4 . 
         FIG. 8  is a right end view of the adjustable-barrel curling iron of  FIG. 5 . 
         FIG. 9  is a perspective view of a portion of a barrel-adjustment assembly of the adjustable-barrel curling iron of  FIG. 1 . 
         FIG. 10  is a longitudinal cross-section view of the barrel-adjustment assembly of the adjustable-barrel curling iron of  FIG. 1 . 
         FIG. 11  is a perspective view of an alternative barrel-adjustment assembly for use with the adjustable-barrel curling iron of  FIG. 1 , with a ring-driven gear and a drive gear shown without all their gear teeth for clarity. 
         FIG. 12  is a perspective view of a barrel-adjustment assembly of an adjustable-barrel curling iron according to a second example embodiment of the present invention. 
         FIG. 13  is a perspective view of the barrel-adjustment assembly of  FIG. 12  shown in a fully expanded position. 
         FIG. 14  shows the barrel-adjustment assembly of  FIG. 13  in a fully expanded position 
         FIG. 15  is a perspective view of a fabric barrel cover for the barrel-adjustment assembly of  FIG. 12 . 
         FIG. 16  shows a perspective view of an adjustable-barrel curling iron according to a third example embodiment of the present invention. 
         FIG. 17  is a perspective view of an adjustable-barrel curling iron according to a fourth example embodiment of the present invention, showing an adjustable barrel in a fully expanded position. 
         FIG. 18  shows the adjustable-barrel curling iron of  FIG. 17  in a fully contracted position. 
         FIG. 19  is a longitudinal cross-section view of a barrel-adjustment assembly of the adjustable-barrel curling iron of  FIG. 17 . 
         FIG. 20  is a longitudinal cross-section view of a barrel-adjustment assembly of an adjustable-barrel curling iron according to a fifth example embodiment of the present invention, shown in a fully contracted position. 
         FIG. 21  is a perspective view of the barrel-adjustment assembly of the adjustable-barrel curling iron of  FIG. 20 , shown in a fully expanded position. 
         FIG. 22  is a perspective view of a barrel-adjustment assembly of an adjustable-barrel curling iron according to a sixth example embodiment, shown in a fully expanded position. 
         FIG. 23  shows the barrel-adjustment assembly of  FIG. 22  in a fully contracted position. 
     
    
    
     DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS 
     The present invention may be understood more readily by reference to the following detailed description of the invention taken in connection with the accompanying drawing figures, which form a part of this disclosure. It is to be understood that this invention is not limited to the specific devices, methods, conditions, or parameters of the example embodiments described and/or shown herein, and that the terminology used herein is for the purpose of describing particular embodiments by way of example only. Thus, the terminology is intended to be broadly construed and is not intended to be unnecessarily limiting of the claimed invention. For example, as used in the specification including the appended claims, the singular forms “a,” “an,” and “the” include the plural, the term “or” means “and/or,” and reference to a particular numerical value includes at least that particular value, unless the context clearly dictates otherwise. In addition, any methods described herein are not intended to be limited to the sequence of steps described but can be carried out in other sequences, unless expressly stated otherwise herein. Any and all patents and other publications identified in this specification are incorporated by reference as though fully set forth herein. 
     With reference now to the drawing figures, wherein like reference numbers represent corresponding parts throughout the several views,  FIGS. 1-10  show an adjustable-barrel curling iron  10  according to a first example embodiment. The curling iron  10  includes a handle  12 , a pivotal clip  14 , a barrel-adjustment assembly  20 , an adjustable barrel  26 , at least one heater  30 , and an adjustable distal tip assembly  40 . 
     The handle  12  can be of a conventional type used in commercially available curling irons, with a generally cylindrical and elongated shape, as depicted. A user interface  13  and controls (not shown) are included, for example, as part of the handle  12 . The user interface  13  and controls can be of a conventional type used in commercially available curling irons, for example, including a temperature control circuit for controlling the temperature, an on/off switch, and other operational controls of the curling iron  10 . 
     The pivotal clip  14  can be of a conventional typical used in commercially available curling irons. Thus, the pivotal clip  14  is pivotally coupled to a fixed component of the curling iron  10  so it can pivot between an open position (not shown) and a closed position (see  FIG. 1 ) where it clamps hair down onto the barrel  26  for curling. For example, the pivotal clip  14  can be attached to attachment tabs on a fixed ring  24  (described below with reference to the barrel-adjustment assembly  20 ). 
     The barrel-adjustment assembly  20  is located at the distal end portion of the handle  12  and the proximal end portion of the barrel  26 . The barrel-adjustment assembly  20  includes a fixed ring  24 , a rotary adjustment ring  22 , a rotation-transferring linkage such as an adjustment gear-set  34 , and a barrel cam  28 . These components can be made of a material such as a hard plastic material. 
     The fixed ring  24  is fixedly attached to a stationary component of the curling iron  10 . For example, the fixed ring  24  can be fixedly attached to the handle  12  by a center connection rod along the longitudinal axis of the curling iron  10  (not shown) or by conventional connecting structures as would be understood by persons of ordinary skill in the art. 
     The rotary adjustment ring  22  is positioned adjacent the fixed ring  24 , for example, between the handle  12  and the fixed ring. In addition, the rotary adjustment ring  22  is rotationally and translationally mounted to a stationary component of the curling iron  10 , for example, the handle  12 . For example, the rotary adjustment ring  22  can include a circumferential flange  35  that rotationally mounts it to the handle  12  and a clutch-plate spring  31  that translationally mounts it to the handle. In this way, the rotary adjustment ring  22  rotates (as indicated by the rotary directional arrows of  FIG. 10 ) and axially translates (as indicated by the linear directional arrows of  FIG. 10 ) relative to the handle  12 , while the fixed ring  24  does neither. 
     The rotary adjustment ring  22  axially translates between an engaged position (see  FIGS. 9-10 ) and a disengaged position (not shown). In the engaged position, the rotary adjustment ring  22  engages (directly itself or indirectly by an anti-rotation assembly) the fixed ring  24 , and in the disengaged position it is retracted from such engagement. For example, the rotary adjustment ring  22  can include a clutch plate  21  that is positioned at its distal end and that engages the fixed ring  24  in the engaged position. The rotary adjustment ring  22  is biased toward the engaged position by the clutch-plate spring  31 . The clutch-plate spring  31  can be provided by for example a compression coil spring (as depicted), a leaf spring, or another elastic member that biases against the distal end-wall of the handle  12 . 
     The adjustment ring  22  further includes an anti-rotation assembly that prevents it from rotating when in the engaged position. The anti-rotation assembly includes at least one protrusion that either extends distally from the rotary adjustment ring  22  to engage a stationary component of the curling iron  10  such as the fixed ring  24  (as depicted), or that extends proximally from a stationary component of the curling iron such as the fixed ring to engage the rotary adjustment ring  22 . In a typical embodiment, for example, the anti-rotation assembly includes a plurality of evenly spaced protrusions  23  arranged in a circle on the distal surface of the clutch plate  21  that are received in a plurality of alignable recesses  25  on the proximal surface of the fixed ring  24  (see  FIGS. 9-10 ). Thus, the recesses  25  on the proximal surface of the fixed ring  24  are evenly spaced by the same distance and arranged in a circle of the same radius as the protrusions  23 . The protrusions  23  and recesses  25  can be generally semi-spherical (as depicted) or they can have another regular or irregular shape such that they mate together. When the adjustment ring  22  is in the engaged position, the protrusions  24  are received in the recesses  25  while the clutch-plate spring  31  biases the clutch plate against the fixed ring  24 , thereby restraining the adjustment ring  22  from rotational motion. But when the adjustment ring  22  is in the disengaged position, the protrusions  24  are retracted from the recesses  25 , thereby freeing the adjustment ring  22  to be rotated by the user. 
     In alternative embodiments, the protrusions extend proximally from the fixed ring and the recesses are formed in the distal surface of the clutch plate. And in other alternative embodiments, the at least one protrusion of the anti-rotation assembly is provided by a pawl of a ratchet assembly, a tab or hook, or another protruding structure that selectively interferes with another element to prevent rotation of the adjustment ring  22  when its in the engaged position. 
     The adjustment gear-set  34  includes an adjustment drive gear  27  and a barrel cam gear  29  that meshingly engage each other when the adjustment ring  22  is in the engaged position (see  FIGS. 9-10 ) but that are not engaged when the adjustment ring  22  translated to the disengaged position. The adjustment drive gear  27  is fixedly coupled to the adjustment ring  22  so that they rotate together. For example, a drive gear shaft  32  can extend through an aperture in the proximal end-wall of the fixed ring  24  and connect the clutch plate  21  and the drive gear  27 . The barrel cam gear  29  is rotationally coupled to a stationary component of the curling iron  10  such as the fixed ring  24  so that the cam gear is free to rotate when driven by the drive gear  27 . For example, a cam gear shaft  33  can extend from the cam gear  29  and rotationally connect to the proximal end-wall of the fixed ring  24 . In alternative embodiments, a rotation-transferring linkage is provided without gears but with other linkages that transfer the rotary motion of the adjustment ring  22  to the barrel cam  28 , including for example, pulley systems, belts, chains, or the like. 
     The barrel cam  28  extends longitudinally from the barrel cam gear  29  and is non-concentric with the fixed ring  24  (see  FIGS. 9-10 ). The barrel cam  28  can be provided by an elongate member with a length that extends at least a substantial portion of the length of the barrel  26 . 
     The barrel  26  is constructed from a strong, flexible, thermal-conductive material, such as light gage steel. The material is initially in the shape of a flat sheet, and is then rolled into a generally cylindrical shape. In cross-section, the cylindrical barrel  26  has overlapping inner and outer ends  36  and  37  in a spiral configuration. The inner end  36  of the barrel  26  is attached to the barrel cam  28 , and the barrel is coiled around the barrel cam non-concentrically. The barrel  26  is radially adjustable between an expanded position (see  FIGS. 1 ,  3 , and  6 ), at least one intermediate position (see  FIGS. 4 and 7 ), and a contracted position (see  FIGS. 2 ,  5 , and  8 ). 
     The heater  30  can be provided by a flexible heating element made of kapton, mylar, silicone, or another material, that is bonded or otherwise attached to the inner surface of the barrel  26  to provide heat to the barrel. The heater  30  is sized and constructed so that it coils around the barrel cam  28  when the barrel  26  is adjusted smaller. This enables the heater  30  to remain in constant and continuous contact with the barrel  26  to provide even and uniform heating. To insure proper heating of the barrel  26 , a thermistor can be attached to the bottom of the heater  30  and barrel to provide feedback to the temperature control circuit. All wires for the heater  30  and thermistor can be routed through an aperture in an inner surface of the fixed ring  24  near the barrel cam  28 . By positioning the wires through this aperture in this location, bending and flexing of the wires is minimized during the adjustment of the barrel  26 , and the wires are concealed and protected from the moving parts throughout the entire range of motion. In alternative embodiments, the heater can be provided by electric heating rods, coils, or other conventional heating elements that are attached to or positioned proximate the barrel to provide heat to the barrel. 
     The adjustable distal end assembly  40  is located at and forms the distal end of the curling iron  10 . The adjustable distal end assembly  40  includes a plurality of fan blades  42  and a distal tip cover  16 . The fan blades  42  are coupled to and extend between the tip cover  16  and the distal end of the barrel  26  such that they overlap and layer upon one another in a decreased-diameter arrangement when the barrel  26  is in the contracted position and they fan out into an increased-diameter arrangement when the barrel is in the expanded position (see  FIG. 1 ). In this way, the adjustable distal end assembly  40  provides adjustable coverage for the open end of the barrel  26  as its diameter is radially adjusted (increased or decreased). 
     For example, in the depicted embodiment, the fan blades  42  are elongated and generally triangular, and are made from a flexible and heat resistant material. The wide ends of the fan blades  42  are attached to the distal end portion of the barrel  26  and the narrow ends are attached to the tip cover  16 . And the tip cover  16  is attached to the distal end of the barrel cam  28 , which in the depicted embodiment has a length that extends longer than that of the barrel  26 . 
     Having described the major components and construction of the curling iron  10 , its operation and use will now be described. In  FIGS. 1 ,  3 , and  6 , the barrel  26  is the expanded position and the rotary adjustment ring  22  is in the disengaged position. Thus, the drive gear  27  and the cam gear  29  are out of engagement with one another and the clutch plate  21  is fully biased against the fixed ring  24  with the protrusions  23  fully engaged with the recesses  25 . The curling iron  10  in this state can be used to make larger-diameter curls. 
     To adjust the diameter of the barrel  26  smaller to make small-diameter curls, the user grasps the adjustment ring  22  and translationally moves it to the engaged position of  FIGS. 9-10 . In the depicted embodiment, for example, the user retracts the adjustment ring  22  in the proximal direction indicated by the linear arrows of  FIG. 10 . Retracting the adjustment ring  22  retracts the clutch plate  21  and thereby retracts the protrusions  23  from engagement with the recesses  25 , thereby allowing the adjustment ring to be rotated. Retracting the adjustment ring  22  also retracts the drive gear  27  from its disengaged position forward/distal of the cam gear  29  into the depicted engaged position with the teeth of the two gears meshing. With the adjustment ring  22  so retracted, the user then rotates the adjustment ring  22  as indicated by the rotational arrows of  FIG. 10 . This rotation in turn rotates the drive gear  27 , which rotationally drives the cam gear  29  (in an opposite direction), which in turn rotates the barrel cam  28 . The rotation of the barrel cam  28  pulls on the inner end  36  of the barrel  26  and causes it to rotate and wrap around the barrel cam as it submerges under the outer end  37  of the barrel. Thus, as the adjustment ring  22  is rotated, the barrel cam  28  rotates and winds in the barrel  26  around it to cause the barrel to have a decreased diameter. 
     As can be seen by the position of the inner end  36  of the barrel  26  in  FIGS. 4 and 7 , in the depicted embodiment the barrel cam  28  has been rotated by about 90 degrees to adjust the barrel  26  to the intermediate position shown. The user then returns the adjustment ring  22  to the disengaged position. In the depicted embodiment, for example, the user merely releases the adjustment ring  22 , then the clutch-plate spring  31  biases it back to the disengaged position and the anti-rotation assembly holds it there (e.g., with the protrusions  23  engaging the recesses  25  they are then aligned with to lock the clutch plate  21  against any unwanted angular rotation). As can also be seen, the non-concentric arrangement of the barrel cam  28  and the barrel  26  allows the pivotal clip  14  to rest along the surface of the barrel even though the diameter of the barrel has been changed. The user can now use the curling iron  10  to make curls with a smaller diameter than could be made in the expanded position. 
     This same adjustment process can be used to adjust the diameter of the barrel  26  larger back to the expanded position or smaller to the contracted position (see  FIGS. 2 ,  5 , and  8 ). For example, when adjusting the barrel  26  from here to the contracted position, the process is repeated. As can be seen in  FIGS. 5 and 8 , in the depicted embodiment the barrel cam  28  has been rotated by an additional about 90 degrees from the intermediate to the contracted position. And when returning the barrel  26  from the intermediate to the expanded position, the process is repeated except that the adjustment ring is rotated in the opposite direction to unwrap the barrel from the cam  28 . 
     The barrel-adjustment assembly  20  and the barrel  26  can be constructed to provide a plurality of preset barrel diameters that are commonly used and seen in the market. For example, the protrusions  23  and the recesses  25  can be positioned and spaced to align and mate at positions of the adjustment ring  22  that produce a minimum and maximum diameter of the barrel  26  of 0.75 and 1.75 inches, respectively, with 0.25 inch increments. In this example, the curling iron  10  can be adjusted to five positions having barrel diameters of 0.75, 1.00, 1.25, 1.50, and 1.75 inches, thereby enabling a single one of the curling irons  10  to do the job of five conventional curling irons. In addition, the protrusions  23  and recesses  22  of the anti-rotation assembly form detents, and their circumferential spacings can be selected to define discrete adjustment positions of the barrel  26 . One skilled in the art will recognize that a number of possible combinations and permutations for the sizing and arrangement of the barrel  26  and the barrel-adjustment assembly  20  can be provided to produce a number of different barrel sizes and discrete adjustment positions. 
     With reference now to  FIG. 11 , an alternative barrel-adjustment assembly  120  is shown that can be substituted into the design of the curling iron  10 . The barrel-adjustment assembly  20  includes a fixed ring (not shown), a rotary adjustment ring  122 , an adjustment gear-set  135 , a barrel cam  128 , and a ball detent assembly  131 . The fixed ring, a rotary adjustment ring  122 , and the barrel cam  128  are similar to those described with respect to the first example embodiment. 
     The adjustment gear-set  135  includes a cam gear  129  that rotates the barrel cam  128 , and a drive gear  127  that drives the cam gear, similar to those described with respect to the first example embodiment. In this embodiment, however, the adjustment gear-set  135  includes a ring gear  154  and a ring-driven gear  152 . The ring gear  154  is mounted to the adjustment ring  122 , for example, with its teeth facing radially inward, and drives the ring-driven gear  152 . The ring-driven gear  152  is coupled to the drive gear  127 , for example by a connecting body  156 , so that they rotate together. In this way, as the adjustment ring  122  is rotated, the ring gear  154  rotationally drives the ring-driven gear  152 , which in turn rotates the drive gear  127 , which in turn rotationally drives the cam gear  129 , which rotates the barrel cam  128 , thereby adjusting the diameter of the barrel. 
     In addition, the ball detent assembly  131  can be provided by a cylinder with an detent ball recessed therein and outwardly spring-biased. The ball detent assembly  131  is positioned and configured so that the detent ball engages with the teeth of the ring gear  154 . The ball detent assembly  131  thereby provides a resistive force against the teeth of the ring gear  154  that prevents the ring gear from accidently rotating. However, the outward force of the ball detent assembly  131  can be overcome by applying a strong enough rotational force to the adjustment ring  122 , allowing the barrel  126  to still be adjusted by the user as desired. Thus, the ball detent assembly  131  serves as an anti-rotation assembly to prevent unintended rotating of the adjustment ring  122  and mis-adjustment of the barrel  126 . The ball detent assembly  131  can be mounted to the fixed ring or another stationary component of the curling iron. 
     As used herein, a ball detent assembly is any type of detent mechanism with a spring-biased extension and retraction member (not just a ball) that is biased into engagement with the ring gear teeth to hold the adjustment ring from rotation unless a sufficiently large rotary overcoming force is applied to the adjustment ring. 
     With reference now to  FIGS. 12-15 , there is shown a barrel-adjustment assembly  220  of an adjustable-barrel curling iron according to a second example embodiment of the present invention. The barrel-adjustment assembly  220  includes a guide plate  221 , a rotary adjustment ring  222 , an adjustment ring gear  227 , a plurality of planet gears  229 , a plurality of finger cam arms  228 , and a plurality of heated fingers  230 . The guide plate  221  is fixedly attached to the handle (not shown) or another stationary component of the curling iron. The rotary adjustment ring  222  rotates relative to the guide plate  221 , for example, it can be rotationally coupled to the guide plate, the handle, or another stationary component of the curling iron. The rotationally coupling can be provided for example by a circumferential flange of the guide plate  221  being received in a circumferential groove of the adjustment ring  222 , or vice versa. The ring gear  227  is positioned within the rotary adjustment ring  222  with its gear teeth engaging and driving the gear teeth of the planet gears  229 . For example, the gear teeth of the ring gear  227  can extend radially inward and the gear teeth of the planet gears  229  can extend radially outward into mating cooperative engagement, as depicted in  FIG. 12 . The planet gears  229  are attached to and drive the finger cam arms  228  in a one-to-one relationship. For example, pivot shafts (not shown) can extend through apertures  226  in the guide plate  221  to connect the planet gears  229  to the finger cam arms  228 . The heated fingers  230  extend distally from the finger cam arms  228  and are connected to them at a location spaced apart from the connection location of the pivot shafts, the finger cam arms thereby forming moment arms. 
     In this way, when the rotary adjustment ring  222  is rotated, the ring gear  227  attached to it rotationally drives the planet gears  229 . And the rotating planet gears  229  then rotationally drive the finger cam arms  228 , which causes the heated fingers  230  to swing between the expanded position of  FIGS. 12-13  and the contracted position of  FIG. 14 . In particular, when the barrel-adjustment assembly  220  is in the expanded position of  FIGS. 12-13  and the rotary adjustment ring  222  is rotated clockwise, the finger cam arms  228  and the heated fingers  230  are rotated clockwise about the pivot shafts to the contracted position of  FIG. 14 . And when the barrel-adjustment assembly  220  is in the contracted position of  FIG. 14  and the rotary adjustment ring  222  is rotated counter-clockwise, the finger cam arms  228  and the heated fingers  230  are rotated counter-clockwise about the pivot shafts back to the expanded position of  FIG. 12-13 . 
     In addition, the guide plate  221  can include a plurality of curved cam-arm guide tracks  225  formed in it and the finger cam arms  228  can include guide extensions (not shown) extending proximally from them and riding along the cam-arm guide tracks. In this way, the cam-arm guide tracks  225  and the cam-arm guide extensions cooperatively provide additional guidance for a smooth and easy radial-adjustment motion. In the depicted embodiment, the am-arm guide tracks  225  are provided by curved slots extending through the guide plate  221  and through which electrical wires can be routed for powering the heated fingers  230 . 
       FIG. 15  shows a radially expandable barrel  226  that fits over the heated fingers  230  and expands and contracts with them between the expanded position of  FIGS. 12-13  and the contracted position of  FIG. 14 . Thus, the barrel  226  stretches radially outward to match the outer diameter defined by the heated fingers  230  in the expanded position and elastically contracts radially inward to match the outer diameter defined by the heated fingers in the contracted position. The barrel  226  can be provided by a fabric-coated sleeve made for example from a stretchable nylon material. The fingers  230  define a generally circular layout and the barrel  226  can sheath the entire plurality of heated fingers  230  simultaneously while forming a cylindrical surface. 
       FIG. 16  shows an adjustable-barrel curling iron  310  according to a third example embodiment of the present invention. The curling iron  310  comprises a handle  312 , a primary smaller-diameter barrel  326   a , a secondary intermediate-diameter barrel  326   b , and a tertiary larger-diameter barrel  326   c . The barrels  326   a - c  are arranged in a generally telescopic arrangement, with the primary barrel  326   a  slidingly received within the secondary barrel  326   b , which in turn is slidingly received within the tertiary barrel  326   c , which in turn is slidingly received within the handle  312 . The barrels  326   a - c  can be pulled out individually or in combination to provide the desirable diameter for curling hair (as shown by the three directional arrows). For example, the primary barrel  326   a  can be extended for use with the secondary and tertiary barrel  326   b - c  remaining nested within the handle  312 . Or the primary and secondary barrels  326   a - b  can be extended together, with the primary barrel remaining nested within the secondary barrel and with the tertiary barrel  326   c  remaining nested within the handle  312 , for use of the secondary barrel. The barrels  326   a - c  can be held in place by releasable fasteners such as detents, spring-biased pushpins, radially-tightening collars, or the like, that releasably hold the barrels in user-selected configurations. 
       FIGS. 17-19  show an adjustable-barrel curling iron  410  according to a fourth example embodiment of the present invention. The curling iron  410  comprises a handle  412  and a barrel-adjustment assembly  420 . The barrel-adjustment assembly  420  comprises a smaller-diameter primary barrel  426   a  and a larger-diameter secondary barrel  426   b  that are attached to one another at their ends. The barrels  426   a  and  426   b  have different fixed diameters and are each individually received within an aperture in the handle  412 . The aperture can have a deeper smaller-diameter section for receiving the smaller primary barrel  426   a  with the larger secondary barrel  426   b  exposed for use, and a shallower larger-diameter section for receiving the larger secondary barrel with the smaller primary barrel exposed for use. Thus, the smaller-diameter primary barrel  426   a  can be longer than the larger secondary barrel  426   b  so that it extends into the deeper smaller-diameter section, with the same length of barrel exposed for use in either expanded (larger-diameter) or contracted (smaller-diameter) position. In this way, the barrels  426   a  and  426   b  to be swapped (by inverting the barrel-adjustment assembly  420  as indicated by the directional arrow in  FIG. 18 ) from the contracted (smaller-diameter) position of  FIG. 17  to the expanded (larger-diameter) position of  FIG. 18 . The barrels  426   a  and  426   b  can be made of a heat-conductive material, such as a strip of metal, and heated for use. 
       FIGS. 20-21  show a barrel-adjustment assembly  520  according to a fifth example embodiment of the present invention. The assembly  520  comprises a barrel coil  526 . The coil  526  can be made of a flexible, heat-conductive material, such as a strip of metal, that is coiled about itself along a central axis. The coil  526  is fixed at one end and movable at the other end. The movable end can be pulled or biased outward along the central axis away from the fixed end in order to increase the diameter of the barrel from its contracted position of  FIG. 20  to its expanded position of  FIG. 21 . Similarly, the movable end can be pushed or biased inward along the central axis toward the fixed end in order to decrease the diameter of the barrel from its expanded position of  FIG. 21  to its contracted position of  FIG. 20 . 
       FIGS. 22-23  show a barrel-adjustment assembly  620  according to a sixth example embodiment of the present invention. The assembly  620  comprises a barrel  626  in the form of a woven cylinder, much similar to the weaving pattern of a Chinese finger trap toy. When under a compressive force along its axis of elongation, the barrel  626  compresses to form a larger diameter in its expanded position of  FIG. 22 . When under a tensile force along its axis of elongation, the barrel  626  elongates to form a smaller diameter in its contracted position of  FIG. 23 . 
     While the invention has been shown and described in example forms, it will be apparent to those skilled in the art that many modifications, additions, and deletions can be made therein without departing from the spirit and scope of the invention as defined by the following claims.