EXPANDABLE ROLLER

FIELD OF THE INVENTION

The present invention relates to hair rollers and, more particularly, to hair rollers with a reconfigurable hair curling surface.

BACKGROUND OF THE INVENTION

A typical hair roller comprises a cylindrical roller body with a hair curling surface configured for curling hair by heated contact. In use, a hair roller is heated first and then tresses of hair are wrapped around the roller body to form curls through heat conduction. In another type of hair rollers, tresses of hair are first wrapped on a roller and heat is then applied to the hair to be curled through heating of the roller body by inserting a heated rod into an axial aperture of the hair roller.

Hair curling using conventional hair rollers is essentially by application of heat and tension to the hair being curled. The curling tension applied to the hair is largely obtained by subjecting the hair being curled to conform tightly to the curvature of the roller body. Although a hair roller should ideally engage tresses of hair tightly for maximum curling efficiency, it is noted that tresses of hair always lose some degree of curling tension after the tresses of hair have been wound on a conventional hair roller. On the other hand, when tresses of hair are tightly engaged on a hair roller, it will be difficult to release the curled hair from the roller without adversely affecting the integrity of the curls.

It is desirable if there can be provided a hair curler which mitigates shortcomings of conventional hair rollers.

SUMMARY OF THE INVENTION

According to the present invention, there is provided a hair roller comprising a longitudinally extending hair curling portion defined between a pair of opposed end members, wherein said hair curling portion is expandable and retractable in a radial direction with respect to the longitudinal axis of said hair curling portion in response to relative movement of said end members with respect to each other.

A hair roller having an expandable hair curling portion will provide a user an opportunity to tighten the engagement between the tresses of hair to be styled and the hair curling surface whereby an increased hair curling tension can be applied and the tresses of hair will follow the curvature of the hair roller more closely. On the other hand, the provision of a retractable hair curling portion facilitates easier separation between a hair roller and the hair after curling has been completed.

In an exemplary embodiment of this invention, the hair curling portion and the end members are arranged so that said hair curling portion is expandable and retractable in response to rotary movement of said end members relative to each other. A rotary movement provides a mechanical advantageous arrangement so that a user can adjust the expansion and retraction of the hair portion with ease.

The hair curling portion may be arranged to expand and retract gradually in response to movement of said end members relative to each other. A hair roller

with a gradual expansion and retraction facility will afford a user an opportunity to select an appropriate curl tension and dimension suitable for specific purposes.

As an example, the hair curling portion may assume a longitudinally convexly curved hair curling region located intermediate the end members responsive to said relative movement of the end members.

The convexly curved region may extend circumferentially around said longitudinal axis.

As a further example, the convexly curved region may have a bell-shaped longitudinal profile along its length.

In a convenient example, the end members are interconnected by a rigid tube, and at least one of said end members is moveable relative to said rigid tube such that the longitudinal separation between the end members is variable responsive to rotary movement of said at least one of said end members relative to said rigid tube.

So that a hair roller can obtain operational heat from an external heated rod more efficiently, the rigid tube may be formed from a thermally conductive material.

To facilitate relative movement between the end members, at least one of said end members may be mounted on said rigid tube by threaded engagement.

In an exemplary embodiment, the radial expansion of the hair curling

^' portion is at a maximum mid-way between said end members, and wherein the extent of radial expansion gradually diminishes from said maximum towards said

longitudinal ends. The non-linear longitudinal profile of the hair curling portion across the length of the hair curling portion provides extra curvy effects while achieving the purpose of tightly securing tresses of hair on the hair roller. For example, the extent of radial expansion of said hair curling portion may be at a minimum adjacent the longitudinal ends of said hair curling portion.

In an embodiment, the hair curling portion defines a hair curling surface which may be reconfigurable between a cylindrical surface having a substantially uniform cross-section along its length and a bulged surface having an arcuate longitudinal profile. For example, the bulged surface may have a convexly curved longitudinal profile.

The hair curling portion may comprise a flexible or resiliently deformable cage which comprises a plurality of longitudinally extending flexible or resiliently deformable elongate members which collectively define a hair curling surface.

The deformable cage may overlay the rigid tube and is moveable relative to said rigid tube. In addition, the deformable cage may bulge at or about the middle of its length when subjected to an axial compressive force acting at the axial ends of said cage. Furthermore, the deformable cage may be integrally formed from a resilient metallic sheet, foil or cylinder. For example, the resiliently deformable cage may be formed of steel, aluminium or like resilient materials.

As a useful example, the deformable cage may comprise a plurality of longitudinally extending strips defining a plurality of longitudinally extending channels located there-between, and wherein the totality of said longitudinally extending strips forms a convexly curved bulging surface surrounding said rigid

tube when subjected to an axial compressive force applied at the axial ends of said cage.

Each end member may comprise a circular cap member and at least one of said circular members is rotatable relative to said hair curling portion and about said longitudinal axis, and wherein the separation distance between said cap members is variable upon relative rotation between said circular member and said hair curling portion.

The hair styling portion may expand or retract radially in response to relative rotation between said circular member and said hair curling portion.

BRIEF DESCRIPTION OF THE DRAWINGS

Preferred embodiments of the present invention will be explained in further detail below by way of example and with reference to the accompanying drawings, in which:-

Fig. 1 is a perspective view of a hair roller illustrating a first preferred embodiment of this invention,

Fig. 2 is a side view of the hair roller of Fig. 1 ,

Fig. 3 is a top plan view of the hair roller of Fig. 1 ,

Fig. 4 shows an end view of the roller of Fig. 3 from one end,

Fig. 5 shows an end view of the roller of Fig. 3 from another end,

Fig. 6 is a longitudinal cross-sectional view of the roller of Fig. 1 along the section line B-B of Fig. 3,

Fig. 7 is a perspective view of the roller of Fig. 1 in an expanded configuration,

Fig. 8 is a longitudinal cross-sectional view of the roller of Fig. 7,

Fig. 9 is an exploded view of the hair roller of Figs. 1 to 8,

Fig. 10 is a perspective view depicting a hair roller of a second embodiment of this invention,

Fig. 11 is a longitudinal cross-section of the hair roller of Fig. 10,

Fig. 12 is a side view of the hair roller of Fig. 10,

Fig. 13 is a perspective view depicting a third embodiment of the hair roller of this invention,

Fig. 14 is a longitudinal cross-sectional view of the hair roller of Fig. 13, and

Fig. 15 is a longitudinal cross-sectional view depicting the hair roller of Fig.

10 with the cage in its expanded form.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The hair roller 100 shown in Figs. 1 to 9 comprises a hair curling body 110, a pair of end members 130, 140 and a support shaft 120 formed of a rigid tube which interconnects the end members.

The support shaft 120 comprises a rigid tube which is formed from metal or a metal alloy. An end member 130 is fixedly attached to one axial end of the support shaft 120 while the other end member 140 is moveably attached to the other axial end of the support shaft 120 via screw threads. The end members comprise circular caps which are coaxial with respect to each other and/or with respect to the support shaft. With such a coupling engagement, the end members are rotatable relative to each other about the longitudinal axis, and when the end members so rotate, the axial or longitudinal distance of separation between the end members is variable. Due to the helical or screw threaded coupling between an end member 140 and the rigid tube, the axial separation between the end members is variable through relative rotary movement of the end members about the longitudinal axis of the hair curling body. More particularly, the end members can move axially towards and away from each other to vary the effective length of the hair styling portion by rotating the screw cap 142 on the screw thread. In use, a user can rotate the screw cap 142 and therefore the end member 140 to advance or retreat the end member 140 towards or away from the other end member 130.

Each of the end members comprises an insulating outer cover 132, 142. Each insulating cover is substantially circular, similar to an end member of a conventional hair roller. The insulating cover is made, for example, of plastics or other appropriate insulating materials. A plurality of graduations is formed on the circumference of the circular end members to provide a friction contact interface for facilitate easier rotation of the moveable end member 140 by a user. .

The hair curling body 110 comprises a resiliently deformable cage which is resiliently expandable when subject to an axial compressive force which is applied at the longitudinal ends of the cage. The cage comprises a pair of opposed end rings which are interconnected by a plurality of elongate strips and each of the rings is adjacent to a corresponding end member. The elongate strips are parallel and are distributed around the circumference of the circular ring. An elongate channel is defined intermediate a pair of adjacent elongate strips and the plurality of elongate strips collectively define a plurality of elongate channels which are distributed around the circumference of the circular rings. More particularly, the elongate strips are evenly distributed around the circumference of the circular rings. The cage is integrally moulded or stamped from a single metallic sheet or foil to provide adequate uniformity of resilience. In addition, the elongate strips are covered by a thermal insulator, such as, for example, velvet or other fabrics, which also provides friction against relative movement between the hair curling portion and the hair under retention.

In its neutral and un-deformed form, the cage is substantially cylindrical with its longitudinal axis coaxial with that of the support shaft and having a substantially uniform circular cross section along its length, as shown in Figs. 1 to 6 and 9. To provide adequate resilience so that a deformed (or radially expanded) cage will return to its neutral (or retracted) form when the deformation tension has been removed, the cage is formed from a resilient material such as steel, copper, aluminium or other resilient metal or metal alloys.

The cylindrical metal cage is carried on the support shaft 120 with its longitudinal ends in contact with or in proximity of the end members 130, 140. To

allow relative slide movements between the support shaft and the cage, the cross- section of the metal cage is slightly larger than that of the support shaft. The metallic cage is adapted so that when the pair of end members 130, 140 move towards each other, the resulting lateral compressive force will cause the metal cage to bulge near its middle, as shown in Figs. 7 and 8. When the lateral compressive force is removed, the resilience of the metallic cage will return to its un-stressed cylindrical shape. The metallic cage is made, for example, of aluminium sheet with a plurality of longitudinally extending metallic strips 112 separated by another plurality of longitudinal channels or elongate apertures 114 so that the metallic strips will be bent convexly outward when subject to a lateral compressive force acting on its longitudinal ends. Of course, the metallic cage can be made of other resilient metal such as steel. As an alternative, the metallic cage can be designed so that a plurality of ripples are formed when subject to a lateral compressive force.

An exemplary use of the hair roller of this invention will be described below with reference to the Figures. Initially, tresses of hair are wrapped or wound on the hair curling body 110. When tresses of hair have been wrapped on the hair curling body, the pair of end members is moved towards each other. When the pair of end clamping members are sufficiently moved towards each other, for example, by rotating the screw-threaded end member 140 towards the fixed attached end member 130, the metallic cage is also caused to bulge at its middle portion so that it has a substantially convex arcuate profile along its length and this radial expansion will help to more tightly pack or squeeze the curl along the radial direction to achieve the desirable effects.

In a second embodiment of the invention, construction of the roller 200 is substantially identical to that of the first embodiment, although the cage 216 is integrally formed from rubber or resilient plastics, and the end members 230, 240 are also moulded from rubber, plastics or other insulating materials. Moreover, there are no axially extending protrusions formed on the inside of the end second members, and a plurality of axially extending graduations 238 for friction engagement of the end members by the fingers of a user is distributed on the circumference of the end members.

Unless otherwise specified, features appearing in Figs. 10-12 are designated with the same numerals of Figs. 1-9 plus 100.

In another embodiment, the roller is identical to that of the first embodiment, but the rigid tube is moulded from plastics.

In yet another embodiment, the roller is identical to that of the first embodiment, but no longitudinal hair engaging protrusions extend from the end members.

In a third embodiment as shown in Figs. 13-15, the roller 300 is identical to that of the second embodiment, but some or all of the elongate strips are formed with small protrusions distributed along the length of the strips for providing additional friction for hair retention.

Unless otherwise specified, features appearing in Figs. 13-15 are designated with the same numerals of the second embodiment plus 100.

While the present invention has been explained by reference to the examples or preferred embodiments described above, it will be appreciated that those are examples to assist understanding of the present invention and are not meant to be restrictive. Variations or modifications which are obvious or trivial to persons skilled in the art, as well as improvements made thereon, should be considered as equivalents.

Furthermore, while the present invention has been explained by reference to a hair curler with a metallic cage body, it should be appreciated that the invention can apply, whether with or without modification, to hair curlers with other forms of expandable hair curling surface without loss of generality.