Apparatus and method for drying hair

An apparatus for drying hair includes first and second mutually-opposing arms adapted for movement between an open configuration for receiving a length of wet hair therebetween and a closed configuration adjacent the hair. A vibrator imparts vibration from at least one of the arms to the length of hair in use, to move and separate hair fibres for improving drying of the hair. A method of drying hair includes using the apparatus to impart vibration to a length of wet hair held within the apparatus. The method may further include using the apparatus to style the hair substantially simultaneously with drying the hair.

This application is a National Stage Application of PCT/GB2016/052848, filed Sep. 14, 2016, which claims benefit of British Patent Application No. 1516247.2, filed Sep. 14, 2015, which applications are incorporated herein by reference. To the extent appropriate, a claim of priority is made to each of the above disclosed applications.

FIELD OF THE INVENTION

The present invention relates to an apparatus for drying the hair of a person (or conceivably an animal), for example after washing the hair or as part of a styling process. Such drying of the hair may be performed by a user in respect of their own hair, for example, or by a hair stylist.

As those skilled in the art will appreciate, the expressions “to dry hair”, “drying hair” and such like, as used herein, should be taken to refer to the removal of “unbound” water that exists on the outside of hair when wet. Such “unbound” water should be contrasted with “bound” water, which exists inside individual hairs, and which can be interacted with when heat styling hair. There is no requirement to remove this “bound” water when drying hair in the context of the present invention, although of course removal of some bound water may also occur during the drying/styling process.

BACKGROUND TO THE INVENTION

Conventional handheld hairdryers, that incorporate an electrically-powered motorised fan to blow a current of cool or hot air in order to dry a person's hair, are well known. The fan draws ambient air into the body of the hairdryer and blows the current of air towards the hair to be dried. When hot air is to be blown, typically an electric heating element, incorporated within the body of the hairdryer, is used to heat the current of air before it leaves the hairdryer. Optionally, the hairdryer may be equipped with a concentrator nozzle attachment to intensify and direct the current of air, or a diffuser attachment to deliver the air more gently.

Although conventional hairdryers have been in use for many years, the inventors have observed and identified a number of shortcomings, as follows:

Conventional hairdryers can often be noisy, heavy and bulky. Furthermore, they can be awkward to use, and it can be difficult for a user (in particular a domestic user attending to their own hair) to achieve desired results, particularly in respect of styling the hair whilst drying it. For instance, a hairdryer will often be used simultaneously with a hairbrush or comb, or another piece of styling equipment, to style the hair during drying. The styling process may be, for example, to straighten the hair, or to provide “body and volume” to the hair (if necessary, preceded or succeeded by the application of styling products such as mousse, gel, wax, hairspray, etc.). Simultaneously maneuvering a hairdryer and a brush (or a comb, etc.) around the head can be awkward for the user, and often requires a degree of skill to achieve the desired results.

Moreover, it has been found that, with too gentle a flow of air it can take an unduly long time to dry the hair. Conversely, with too powerful a flow of air (e.g. using a concentrator nozzle), insufficient control can be provided during a styling operation.

Additionally, excessive use of hot air can result in damage to the hair, whereas the use of cool air can again result in the drying process taking an unduly long time.

Consequently there is a desire for hair drying apparatus that can be used to dry hair in a relatively quick manner, whilst also facilitating styling of the hair.

Furthermore, as illustrated inFIG. 13, the use of a conventional hairdryer to dry hair can be hampered by wet hair clinging together to form clumps, creating surface tension between the hair and making it hard for air from the hairdryer to pass though the hair (e.g. between individual hairs) to dry it. That is to say, clumps of wet hair have relatively high airflow resistance, impeding the drying process.

The clinging-together of wet hair into clumps can also give rise to further problems when the hair is subjected to hot air blown by a conventional hairdryer. In particular, the hair on the outside of a clump dries more quickly than the hair on the inside of the clump. Consequently, the hair on the outside of the clump can be damaged (e.g. scorched) by the hot air, whilst the hair on the inside of the clump can remain wet.

Blowing hot air using a conventional hairdryer can also be inefficient in respect of energy usage, as much of the energy in the hot air is lost into the atmosphere as waste heat. This is particularly the case if the hot air is deflected from a clump of wet hair, rather than being allowed to pass between hairs. This is illustrated inFIG. 13, in which a clump of wet hair40is shown in cross-section. An incident flow of hot air56is deflected by the clump of wet hair40. Unbound water (as denoted by51in the enlargement) is shown on the surface of the individual hairs within the clump.

Furthermore, with such a clump, the “active” surface area of the hair (i.e. the surface area of the hair that is exposed to air, and from which evaporation of water can occur) is relatively small in comparison to the overall surface area of the constituent hairs added together, again giving rise to inefficiency in the drying process.

Indeed, more generally, conventional hairdryers have been found to be inefficient in respect of heat transfer and evaporation (i.e. low drying efficiency) and power consumption (i.e. low energy efficiency).

To address some of the above issues, hairdryers which blow more air and/or generate higher pressure air (e.g. so as to force the air through clumps of wet hair) have been considered as possible solutions, but this would likely lead to an increased size and weight of the hairdryer, increased operating noise, and greater inefficiency.

There is therefore a desire for an alternative approach to addressing at least some of the above issues.

SUMMARY OF THE INVENTION

The present invention aims to provide alternative apparatus and methods to those of conventional handheld hair driers in order to dry hair. Embodiments of the invention preferably take a similar form to that of a handheld hair straightener or styler, having first and second mutually-opposing arms which are coupled together by a “hinge” and which are movable relative to one other by virtue of the hinge. The mutually-opposing arms incorporate means to impart vibration to wet hair, to shake off excess water and to promote the drying process. In presently-preferred embodiments the mutually-opposing arms also function as styling arms for the purpose of straightening or otherwise styling the hair. Thus, advantageously, embodiments of the present invention provide, as a single handheld device, means for both drying and styling the hair, which is simple to use, and less awkward than maneuvering a conventional hairdryer around the head simultaneously with a brush, comb or other piece of styling equipment.

More particularly, the vibration imparted on the hair may be of an amplitude and frequency sufficient to cause hairs, which have clumped together when wet, to move and separate (e.g. breaking the surface tension between adjacent wet hairs), thereby increasing the overall surface area of the wet hair exposed to air, and allowing air to pass between the hairs.

According to a first aspect of the present invention there is provided apparatus for drying hair, comprising: first and second mutually-opposing arms adapted for movement between an open configuration for receiving a length of wet hair therebetween and a closed configuration adjacent the hair; and means for imparting vibration from at least one of said arms to said length of hair in use, to move and separate hair fibres for improving drying of the hair.

As a result of this movement and separation of wet hair fibres, by virtue of the imparted vibration, the overall surface area of the wet hair exposed to air is increased, and air is able to pass between the hair fibres, thereby promoting evaporation of water from the surface of the hair fibres. As a result, it may, for example, be possible to dry the hair more quickly or with less energy than would otherwise be the case. Furthermore, in accordance with presently-preferred embodiments, and as mentioned above, the arms may also be used to style the hair, thus providing a dual-purpose device for drying and substantially simultaneously styling the hair.

The means for imparting vibration are preferably configured to impart vibration at a frequency and amplitude sufficient to break surface tension between adjacent wet hair fibres, and thereby cause hairs, which have clumped together within said length of hair, to move and separate.

The apparatus may also include means for applying a hair product onto the hair before or whilst it is vibrated by the vibrating means. The vibration applied to the hair helps to disperse the hair product through the hair. Such a product may be hair gel or the like to hold the hair style once set or it may be a hair protection product that protects the hair from, for example, heat damage. Optionally, the means for applying a hair product may include means for atomising the hair product, such as an aerosol nozzle, to provide a fine, even distribution of the hair product over the hair fibres treated by the apparatus.

The means for imparting vibration may comprise one or more mechanical vibration-imparting members mounted on the at least one arm and configured to move relative to the at least one arm in order to impart the vibration to said length of hair. The movement of the vibration imparting members may be a reciprocating movement or a rotational movement.

The apparatus may further comprise means for blowing or drawing air through said length of hair. One example of such a means for blowing or drawing air is a fan. Such an airflow further promotes evaporation of water from the surface of the hair fibres. The apparatus may further comprise means for heating said air, such as one or more heater elements, and may also comprise means for controlling the heating that is applied by the heating elements.

The first and second arms, when in the closed configuration, may define a chamber across which, in use, the hair passes, and inside which the means for imparting vibration act on the hair. The term “chamber” as used herein should be interpreted broadly, to encompass chambers that are partially open on at least one side, as well as those that are enclosed.

Further, the means for blowing or drawing air may be arranged to blow or draw air though said chamber. The chamber therefore functions as a plenum chamber, directing the flow of air through (and around) the hair therein.

The apparatus may further comprise one or more plates disposed on the first and second arms, the plate(s) being arranged to contact the hair when the first and second arms are in the closed configuration.

For example, the apparatus may comprise mutually-opposing plates disposed on the first and second arms, the mutually-opposing plates being arranged to come together when the first and second arms are in the closed configuration, and sandwich therebetween the wet hair in use. Such mutually-opposing plates can advantageously carry out a “squeegeeing” effect on wet hair that is drawn between the plates in use, thereby removing excess unbound water from the hair. Usually, the means for vibrating is provided separately from these mutually-opposing plates.

Further, first and second plates may be disposed on the first arm, and respective opposing first and second plates may be disposed on the second arm. By providing first and second plates on each arm, the apparatus can be used either way around as it is moved along a length of hair. Additionally, by providing a gap between the first and second plates, a space may be provided in which the hair can vibrate.

In one embodiment, one of the first and second arms is bifurcated to form two sub-regions, the first plate of that arm being disposed on one of the sub-regions and the second plate of that arm being disposed on the other of the sub-regions. The means for imparting vibration may be located in the gap between these sub-regions.

More generally, the plates may be incorporated in the walls of the chamber formed when the first and second arms are in the closed configuration. Accordingly, the plates may define the points of contact between the hair and the chamber in use.

At least one of said plates may comprise means for applying heat to said length of hair in use, when the first and second arms are in the closed configuration. Such means for applying heat may comprise, for example, a heater element disposed within or underneath the respective plate, thereby causing the plate to function as a heater plate. Both the plates in a mutually-opposing pair of plates may be heated. Alternatively, only one may be heated (and the other may, for example, be “dummy” or passive, drawing heat from the plate that is heated, when the plates are brought together).

The application of heat from such heater plates promotes drying of the hair and can also be used to style the hair. The heat from the heater plates may also be used to heat the chamber, although separate means for heating the chamber may optionally be provided, disposed on or within the walls of the chamber.

Optionally, the apparatus may further comprise a moisture and/or temperature sensor arranged to detect, in use, the moisture level or temperature of the hair, and control means (e.g. a suitably programmed microprocessor) configured to adjust, in dependence on the detected moisture level of the hair or temperature of the hair, one or more of: the rate with which air is blown or drawn though the chamber, the temperature to which said air is heated, the temperature of said at least one of said plates, and/or the temperature to which the chamber is heated. Thus, as the moisture level of the hair decreases, the applied temperature and/or airflow may advantageously be reduced, thereby saving energy and avoiding the likelihood of damage to the hair.

In one embodiment, temperature sensors are provided at the hair inlet and at the hair outlet, and the controller uses the sensed temperature difference between the inlet and the outlet to determine the orientation that the user is holding the device when in use. This knowledge can also be used to control the heating applied at the hair inlet and at the hair outlet. For example, higher temperatures may be applied at the outlet to allow improved styling of the user's hair.

Also optionally, the apparatus may further comprise a sensor arranged to measure, in use, the amplitude of movement of the hair due to the imparted vibration, and control means configured to adjust the frequency and/or amplitude of the imparted vibration so as to substantially maximise, or achieve a predetermined level of, the measured amplitude of movement of the hair—e.g. adjusting the frequency of the imparted vibration to a frequency at or near the resonant frequency of the hair (which can vary with time, or due to other factors such as the physical characteristics of the user's hair). By operating at or near the resonant frequency of the hair, this increases the amount of movement of the hair obtained for a given amplitude of imparted vibration, and thereby increases the efficiency of the water removal process.

The means for imparting vibration may take a variety of possible forms.

For example, the means for imparting vibration may comprise one or more vibrating or rotating members arranged to contact the hair in use.

The or each vibrating or rotating member may, for example, comprise a vibrating or rotating plate.

In accordance with certain embodiments, such a vibrating or rotating plate preferably extends away from the surface of at least one of the first and second arms and is arranged such that the edge of the vibrating or rotating plate contacts the hair in use. The or each vibrating or rotating plate is preferably oriented longitudinally (i.e. lengthways) with respect to the chamber.

In one embodiment a single vibrating or rotating plate may be arranged along substantially the midpoint of one of the first and second arms.

In another embodiment, first and second vibrating plates may be respectively arranged on the first and second arms. The first and second vibrating plates are preferably driven in synchronism with one another, such that one plate moves away from its respective arm whilst the other plate moves towards its respective arm, and vice versa. The first and second vibrating plates may, for example, be respectively arranged along substantially the midpoint of the first and second arms. Alternatively, the first vibrating plate may be arranged towards one side of the first arm, and the second vibrating plate may be arranged towards the other side of the second arm.

Optionally the surface of the or each vibrating or rotating plate that contacts the hair in use may have a nonplanar profile configured such as to cause hairs that contact the plate to move away from the plate in a direction that is not parallel to the direction of vibrational motion of the plate. In turn, this may promote the movement and separation of clumped wet hairs.

In an alternative embodiment, the or each vibrating member may comprise one of the plates (heated or otherwise) that come together when the first and second arms are in the closed configuration.

In other embodiments, the or each vibrating or rotating member may comprise some other mechanical article such as a cam, an eccentric disc or a rod that is arranged to contact the hair directly in use, to impart vibrations directly to the hair.

The or each vibrating or rotating member may be driven in a variety of possible ways. For example, a motor may be arranged to drive the or each vibrating or rotating member. In embodiments having a fan, said motor may also be arranged to drive the fan. The motor may directly drive the vibrating or rotating member via a shaft of the motor or the vibrating or rotating member may be driven indirectly using, for example, a flexi-drive to connect to the motor.

Further, an eccentric disc or cam, driven by the motor, may be provided to drive the or each vibrating or rotating member. Alternatively, a wormdrive arrangement may be used, or a crankshaft and a connecting rod, driven by the motor.

In other embodiments having a fan, the fan may have a motor separate from that which is arranged to drive the or each vibrating or rotating member.

Instead of using a motor, a reciprocating solenoid may be arranged to drive the or each vibrating or rotating member.

In certain embodiments the means for imparting vibration may be driven at a frequency in the range of 10 Hz to 1 kHz. For example, the means for imparting vibration may be driven at a frequency in the range of 20 Hz to 60 Hz, and more particularly at a frequency in the range of 40 Hz to 50 Hz. The optimum frequency also depends on the length of the hair (the path length) that is being vibrated by the apparatus. Typically this should be within 10 mm and 80 mm, and ideally when the means for imparting vibration operates at a frequency in the range of 40 Hz to 50 Hz, the path length is preferably between 15 mm and 30 mm.

In other preferred embodiments the means for imparting vibration may be driven at a frequency in the range of 10 Hz to 1 kHz, preferably at a frequency in the range of 40 Hz to 100 Hz, and more preferably at a frequency in the range of 60 Hz to 80 Hz.

In certain embodiments the means for imparting vibration may be driven with an amplitude of vibration in the range of 0.5 mm to 20 mm. For example, the means for imparting vibration may be driven with an amplitude of vibration in the range of 0.5 mm to 10 mm, and more particularly with an amplitude of vibration in the range of 2.5 mm to 5 mm.

According to a second aspect of the present invention there is provided apparatus for drying hair, comprising: first and second mutually-opposing arms adapted for movement between an open configuration for receiving a length of wet hair therebetween and a closed configuration adjacent the hair; and at least one member disposed on at least one of said arms, said member being configured to impart vibration to said length of hair in use, to move and separate hair fibres for improving drying of the hair.

According to a third aspect of the present invention there is provided a method of drying hair comprising using apparatus according to the first or second aspect to impart vibration to a length of wet hair held within the apparatus, the vibration being such as to cause hair fibres within said length of wet hair to move and separate from each other.

The method may further comprise using the apparatus to style the hair substantially simultaneously with drying the hair.

In the figures, like elements are indicated by like reference numerals throughout.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

The present embodiments represent the best ways known to the applicants of putting the invention into practice. However, they are not the only ways in which this can be achieved.

Overview of Combination Hair Dryer/Styler Device

The present embodiments provide examples of all-in-one handheld devices that can be used to dry hair in a relatively quick and easy manner, whilst optionally also facilitating styling of the hair (e.g. to add “body and volume” to the hair, or to straighten it). In each case, the device incorporates means for imparting vibration to wet hair, the amplitude and frequency of the vibrations being sufficient to shake off at least some excess water from the hair and to cause hair fibres, which have clumped together when wet, to move and separate, thereby increasing the overall surface area of the wet hair exposed to air, and allowing air to pass between the hair fibres, thereby promoting evaporation of water from the surface of the hairs.

Whilst the following embodiments include a fan or other means for generating a flow of air, alternative embodiments can be realised in which a fan or other means for generating a flow of air is not provided, instead relying on the vibration imparted to the hair to cause the hair to dry.

Also, whilst the following embodiments include means for applying heat to the hair, to promote drying, alternative embodiments can be realised in which no heat is applied to the hair, instead relying on the vibration imparted to the hair to cause the hair to dry.

Indeed, since vibration is used to promote the removal of water from the hair, in comparison with conventional hairdryers, less (or even no) heat is required, thereby improving the efficiency of the device and removing or at least reducing the likelihood of heat damage to the hair.

The following presently-preferred embodiments, however, use a combination of three principles to provide improved drying performance—namely conduction heating, vibration, and convection heating—as follows:

Conduction heating—to remove excess water via a “squeegeeing” effect and to apply uniform heat distribution across the hair section to excite water molecules (as discussed in greater detail below with reference toFIGS. 2band3).

Vibration—to break the surface tension in clumps of wet hair and improve drying through evaporation. The inventors have found that providing the apparatus with means to impart vibration to wet hair, to move and separate the hair fibres, is effective in increasing the active surface area of the hair (i.e. the surface area of the hair that is exposed to air, and from which evaporation of water can occur). Accordingly, this removes the need for higher pressure air flow and/or higher volume air flow to achieve improved drying performance.

Convection heating—to provide a flow of air within the device and past the hair, to improve evaporation of water, and to channel water and water vapour away from the hair and out of the device.

First Exemplary Embodiment

FIG. 1illustrates (schematically in plan view, and in transverse cross-section) a first embodiment of a combination hair dryer/styler device10.FIG. 2ais an enlargement of the transverse cross-sectional view shown inFIG. 1. The device10includes a vibrating plate20to impart vibration to wet hair, the vibrations being at a frequency and amplitude sufficient to cause hairs, which have clumped together when wet, to move and separate. The device10includes a heated plenum chamber22, heater plates24a-d(each of which may optionally be provided with a comb or bristles to one side, to aid styling), and a fan26to deliver a flow of air32towards the hair40to be dried.

In more detail, the dryer/styler device10comprises first and second mutually-opposing arms12,14, arranged in a broadly similar manner to the arms of a handheld hair styler. The first arm12and the second arm14(which is substantially parallel to the first arm, effectively “above” the first arm, and not shown inFIG. 1) are coupled together by a hinge18, by virtue of which the first and second arms12,14are movable relative to one other. Thus, the first and second arms12,14can be brought together, into a closed configuration, or moved apart, into an open configuration, by a user in use.

The hinge18can incorporate any suitable means for allowing the first and second arms12,14to be moved relative to one other.

The hinge18also incorporates spring means configured to bias the first and second arms12,14into the open configuration, such that the user is required to apply pressure to the arms to close them together (overcoming the effect of the spring means), and such that the arms12,14automatically open, under the effect of the spring means, once the pressure is removed. For example, the hinge18may incorporate a leaf spring or a coiled spring.

The hinge18and the spring means can be one and the same. For example, the spring means itself can be used to couple the first and second arms12,14together, thereby avoiding the need to provide a separate mechanical hinge and simplifying the overall construction of the device. Furthermore, the first and second arms12,14may be formed in a unitary manner (e.g. from a plastics material) with a “U” shaped middle part provided between the first and second arms, the “U” shaped middle part being able to resiliently flex to allow opening and closing of the first and second arms12,14.

The first arm12broadens at the distal end of the device10(i.e. distal from the hinge18) to provide a surface that acts as the “lower” surface of the plenum chamber22. In effect, the plenum chamber22is formed in use by the distal ends of the first and second arms12,14coming together, i.e. when brought into the closed configuration. In the illustrated embodiment the “lower” surface of the plenum chamber22(as provided by the first arm12) is curved, in a manner that broadly corresponds to the shape of the lower half of the fan26. Thus, air flow generated by the fan26is able to flow directly through the plenum chamber22. First and second heater plates24a,24care provided either side of the plenum chamber22on the first arm12. Each of the heater plates24a,24cis provided with a respective electrical heating element25a,25c, which are operable to cause the respective heater plates24a,24cto heat up.

With particular reference toFIG. 2a, the second arm is bifurcated above the broadened region of the first arm12, to form sub-regions14aand14bof the second arm. Sub-regions14aand14bof the second arm are substantially in mirror symmetry to one another, and are respectively provided with first and second heater plates24b,24d, each of which has a respective electrical heating element25b,25doperable to apply heat to the respective heater plates24b,24d. Due to the symmetric arrangement of the device10, in use hair can be drawn through the device10with the device either way around (i.e. with sub-region14bpreceding sub-region14a, or with sub-region14apreceding sub-region14b). Merely by way of example, the device10inFIG. 2a(and in subsequent figures) is depicted as having a direction of movement M from right to left, i.e. with sub-region14apreceding sub-region14b, although it may alternatively be used in the opposite direction.

The sub-regions14aand14bof the second arm, and the first and second heater plates24b,24dthereon, are arranged such that, when the device10is in the closed configuration, the first and second heater plates24b,24dcome into contact with the first and second heater plates24a,24cof the first arm12. Preferably the heater plates24a,24b,24c,24dare made of a material having relatively high thermal conductivity.

A fan26is mounted on the first arm12and is driven by an electric motor28. The fan26draws in air from the surrounding environment, e.g. via inlets30, and delivers a flow of air32through the heated plenum chamber22, around and through the hair to be dried. The fan26may blow (as illustrated) or draw the air through the plenum chamber22.

In the case of a flow of air32blown by the fan26, as illustrated, the flow of air32may be heated by one or more heater elements27disposed proximal to the fan. Alternatively, in the case of a flow of air drawn by the fan, heater elements may be provided at the distal end of the plenum chamber22from the fan26, so as to heat the air as it enters the plenum chamber22. However, having the fan blow air through the plenum chamber, as illustrated, is considered preferable to having it draw air through the plenum chamber, since blowing the air enables water removed from the hair to be more easily expelled from the device, though the open end of the plenum chamber22distal from the fan26. It also enables the heater element(s)27to be mounted within the body of the device, near to the fan26, as illustrated, which is safer from the user's point of view than having the heater elements mounted at the open end of the plenum chamber22, distal from the fan.

The heater plates24a-dserve a number of purposes during use of the device10. Firstly, with the user having sandwiched a length of wet hair40between opposing plates24aand24band between opposing plates24cand24d(i.e. transversely across the plenum chamber22, with the first and second arms12,14in the closed configuration), and by drawing the device along the length of wet hair40(e.g. in direction M, normally away from the user's scalp), the heater plates24a-dsubject the wet hair40to a squeegeeing effect, removing excess unbound water, and also heat the hair40to promote subsequent evaporation of the water. Secondly, the heating provided by the heater plates24a-dcauses the walls of the plenum chamber22to be heated (via thermal conduction), and also helps maintain the temperature of the air flow32delivered through the plenum chamber22by the fan26. (In alternative embodiments, though, the plenum chamber may be provided with its own heating element(s).) Thirdly, the heater plates24a-dcan be used to style the hair once dry, the styling effectively being performed as an integral continuation of the drying process.

The heater plates24a-dare preferably configured as float plates with springs having a low spring rate or stiffness, thereby giving good control of hair tension.

The first arm12also includes a vibrating plate20which is arranged longitudinally with respect to the length of the plenum chamber22(i.e. lengthways relative to the plenum chamber22, at substantially a right angle to the length of hair40which passes transversely across the plenum chamber22in use). Further, the vibrating plate20extends upwardly from the surface of the plenum chamber22, to such an extent that the upper edge of the plate20contacts the transverse length of hair40in use, and is configured to vibrate in an “up and down” oscillating manner, i.e. exhibiting reciprocating motion, thereby imparting vibration to the hair40.

In this embodiment the motion of the vibrating plate20is driven by a shaft34coupled to the fan26, and hence is driven by the same electric motor28as the fan26. As those skilled in the art will appreciate, a number of mechanical techniques exist for achieving reciprocating motion of the vibrating plate20from the rotary motion of the shaft34—for example through the use of an eccentric disc or cam35(as illustrated inFIG. 2a), for example together with a spring or a cam follower; or by using a crankshaft and a connecting rod, etc.

The vibrating plate20provides means for imparting vibration to a length of clumped wet hair40in use, causing the length of hair to rapidly and repeatedly move between positions40and40′ as shown inFIG. 2a, and thereby causing the hair fibres to separate (e.g. as a result of breaking the surface tension between adjacent wet hairs). This quickly results in an increase in the “active” surface area of the hair (i.e. the surface area of the hair that is exposed to air, and from which evaporation of water can occur), thereby allowing air to pass between the hairs, and promoting evaporation of water from the surface of the hairs.

The electrical and electronic circuitry of the device10is housed within the first and second arms (although predominately within the first arm12). In the example illustrated, a printed circuit board assembly (PCBA)36is provided within the first arm12. Electrical power is provided to the device10by means of a power supply38located at the end16of the device proximal to the hinge18. In the presently-preferred embodiment the power supply38is an AC mains power supply. However, in an alternative embodiment the power supply38may comprise one or more DC batteries or cells (which may be rechargeable, e.g. from the mains or a DC supply via a charging lead), thereby enabling the device10to be a cordless product.

As those skilled in the art will appreciate, a switch (not illustrated) may be provided on the device10to enable it to be turned on or off, together with an indicator light (not illustrated) to show whether the power is on. A sound can also be played by a sound generator (not illustrated) when the device10is switched on and ready to use. Together, the switch, light and sound generator (if included) form a user interface (68inFIG. 12). In alternative embodiments the user interface may include additional components (such as, for example, further display means, to provide the user with more information on the operational status of the device).

Method of Use

In use, the device10is turned on, energising heating elements25a-dand causing heater plates24a-dto heat up and the plenum chamber22to be heated. The user then opens the first and second arms12,14and, normally starting from the roots of the hair (i.e. near the scalp), a length of wet hair40(which may be clumped) is introduced between the arms12,14, transversely across the plenum chamber22. The user then closes the arms12,14so that the wet hair40is held between the first and second arms12,14. Thus, the length of wet hair40is held between the respective first heater plates24a,24bof the first and second arms12,14, and also between the respective second heater plates24c,24dof the first and second arms12,14.

Upon closing the arms a micro-switch (not shown) or a user operated button (not shown) is activated which starts the fan26to deliver an air flow32that is heated by the heater element(s)27, and that causes the vibrating plate20to vibrate. Alternatively, the fan26and the vibrating plate20may operate continuously once the device is switched on. The vibration of the vibrating plate20imparts vibration to the length of wet hair40within the plenum chamber22, causing the hair fibres to move and separate, thereby increasing the overall surface area of the wet hair exposed to the air flow32, and allowing the air flow32to pass between the hair fibres, thus promoting evaporation of water from the surface of the hairs.

The device10is pulled along the length of the hair, away from the roots and towards the hair tips, in a manner similar to that which would be employed with a conventional hair styler device, but in this case causing the hair to be dried and (in this embodiment) simultaneously enabling it to be styled. As discussed above, due to the symmetric arrangement of the device10, the hair can be drawn through the arms12,14in either orientation—i.e. with sub-region14bpreceding sub-region14a, or with sub-region14apreceding sub-region14b; and therefore, the user can use the device in either orientation using their left or right hands.

Water Removal Mechanisms

The mechanisms by which water is removed from the wet hair by the device10will now be discussed in more detail with reference toFIGS. 2aand 2b. Specifically, for each of the three stages of heat transfer/water removal identified inFIG. 2b, the graph illustrates the variation in hair temperature and the amount of unbound water with position. Reference is also made toFIGS. 3, 4a,4band5, which illustrate some of the principles and mechanisms employed.

Stage 1—Squeegeeing and Conduction of Heat

As illustrated inFIG. 2b, in a first stage (S1) of water removal the wet hair40passes between a first pair of opposing thermally-conductive heater plates (e.g. plates24aand24billustrated inFIG. 2a), the hair40being sandwiched between the heater plates24a,24bas illustrated inFIG. 3. The closed-together heater plates24a,24bare then drawn in a given direction (e.g. direction M) relative to the hair40. During this process, the hair40is subjected to a squeegeeing effect, which removes excess unbound water from the hair. At this stage, the hair temperature also increases due to conduction of heat from said first pair of heater plates24a,24b, thereby exciting the water molecules within the hair fibres and initiating the evaporation process. The uniform distribution of heat across the heater plates24a,24bprovides efficient pre-heating of the hair by exciting the water molecules, in preparation for evaporation of the water in the subsequent stages.

Stage 2—Convection and Vibration

As the device10is moved along the user's hair, the hair40that has been treated in stage 1 enters the plenum chamber22and, as a second stage (S2) of water removal, is subjected to vibration from the vibrating plate20and a flow of hot air from the fan26. Vibration forces (due to the vibrating plate) break the surface tension of the wet hair, and move and separate wet hairs that have clumped together. The flow of hot air from the fan26(i.e. heat transfer by convection) evaporates the majority of the water content from the surface of the hair, and carries the evaporated water out of the end of the plenum chamber22distal from the fan26.

FIGS. 4a, 4band5illustrate the mechanisms by which, during this vibration and convection stage, water is evaporated from the hair.

Firstly,FIG. 4aillustrates how vibration helps to redistribute water within a section of clumped wet hair40. Individual hairs within the clump40are denoted by the solid circles50. Differing amounts of unbound water (e.g.52,54) are shown on the surface of the hairs50. By virtue of the applied vibrations, water is transferred from hairs50that have a greater than average amount of water on them (e.g.54), to hairs that have less than an average amount of water on them (e.g.52). The arrows between the circles inFIG. 4aindicate such redistribution of water between the hair fibres within the section of hair40.

In addition to redistributing water, the vibration applied to the hair can also be used to distribute various “wet line” products, such as hair gels, hair heat protection products and the like. The vibration helps to distribute the hair product through the hair. A product applicator (not shown) may be provided at the hair inlet that outputs a steady supply of the hair product to the hair that is passing through the inlet. A product applicator (not shown) may also be provided towards the outlet of the device10, to apply a product that can protect the user's hair from heat damage caused by the heaters at the outlet of the device10. Moreover, the product applicator may include atomising means (e.g. an aerosol nozzle), to provide a fine mist of the hair product in the chamber through which the hair passes. By virtue of the vibration of the hair within the chamber, this results in an even application of the hair product to the individual hair fibres.

Moreover, through relative movement and separation of the hairs, vibration also increases the active surface area of the hair from which evaporation of water can occur, thus helping the hair to dry more quickly. This also helps to prevent (or at least reduce the occurrence of) temperature differences across the hair section, thereby reducing damage to the hair.

FIG. 4billustrates how vibration of the clump of wet hair40enables a flow of air56to pass through the hair section with reduced air flow resistance. This is achieved by forces, imparted on the hair due to the vibration, breaking the surface tension in the wet hair, moving and separating the hairs, and thereby reducing air flow resistance. Air flow between hairs50is thereby promoted, aiding evaporation of water from the surface of the hairs. Furthermore, the vibrational movement of the hair section can cause a pressure differential across the hair section, thereby creating additional airflow through the section and giving rise to increased evaporation of water. Temperature differences across the hair section are also reduced, as mentioned above.

FIG. 5illustrates effects of the surface of the heated plenum chamber22on the drying of the section of clumped wet hair40. Specifically, whilst the hair is vibrated, the conductively heated plenum chamber22helps to maintain the temperature of the air in the chamber as evaporation of water occurs, thereby maintaining a high rate of evaporation. Moreover, if the hair contacts a heated surface (e.g.22aor22b) of the plenum chamber22, the surface of the plenum chamber22transfers heat into the hair, again maintaining a high rate of evaporation. Further, as the hair moves (due to being vibrated) and comes near to, or into contact with, a heated surface (e.g.22b) of the plenum chamber22, a region of positive air pressure (Pa+) can be created that helps to push air through the hair section, towards a lower pressure region (Pa−) on the other side of the plenum chamber, thereby further promoting evaporation of the water from the hair.

The surface of the plenum chamber22may be smooth, or may be textured or grooved. A textured or grooved plenum surface helps unwanted liquid water to drain away or to evaporate, away from the hair.

Stage 3—Conduction of Heat

Referring again toFIGS. 2aand 2b, as the device10is moved further along the hair, the hair that has been treated in stage 2 passes between the second pair of opposing heater plates (e.g. plates24cand24dillustrated inFIG. 2a), as a third stage of water removal (S3). Here, as the hair becomes dry, its temperature reaches a state of equilibrium with the temperature of said heater plates, due to conduction of heat. During this stage, the remainder of the water is evaporated from the surface of the hair. The hair can also be styled by said heater plates during this stage.

With regard to both stages 1 and 3 above, the heater plates24a-denable good control of both the drying and the styling processes.

Operating Parameters (Optionally with Feedback Control)

Values of various operating parameters that have been found to give good results in respect of the above stages 1-3 will now be discussed.

Stages 1 and 3—Conduction of Heat

Operating the heater plates24at a temperature in the range of 30° C. to 185° C. has been found to provide good heat transfer by conduction. However, it is preferred that the heating applied by the heating plates24on the hair inlet side is lower than the heating applied by the heating plates24on the hair outlet side. In particular, on the hair inlet side, the heating plates are preferably operated in the range of 60° C. to 135° C. 135° C. is the denaturation temperature of wet hair and so, on the inlet heater side (where the hair is likely to be the wettest), the temperature should be kept below 135° C. This also reduces cavitation of water when the wet hair comes into contact with the heater plates24on the inlet side. On the outlet side, however, the hair should be dryer and so the heater plates24can be operated at a higher temperature (above 135° C.) allowing for better styling/straightening of the hair.

Optionally the device10may be provided with a moisture and/or a temperature sensor (64inFIG. 12), in the plenum chamber22and/or at the inlet and/or outlet thereof, together with temperature regulation means, e.g. as a feedback loop system, to regulate the temperature of the heater plate element(s)25and/or the fan heater element(s)27in dependence on the moisture level or temperature of the hair as sensed by the moisture/temperature sensor. Thus, as the moisture level of the hair decreases, the applied thermal power may be increased. The speed of operation of the fan motor28may also be reduced as the moisture level of the hair decreases.

Stage 2—Convection and Vibration

The following parameters for air flow from the fan26in the plenum chamber22have been found to provide good heat transfer by convection:Air flow temperature: 30° C. to 185° C.Static pressure: 20 Pa to 2000 PaAir flow rate: 0.03 m3/min to 2 m3/min

Moreover, the following parameters in respect of the vibration frequency and amplitude of the vibrating plate20have been found to provide good results in respect of moving and separating wet hairs within a clump:Vibration frequency: 10 Hz to 1 kHz, preferably 20 Hz to 60 Hz, and more preferably 40 Hz to 50 Hz.Vibration amplitude (peak to peak): 0.5 mm to 20 mm, preferably 0.5 mm to 10 mm, and more preferably 2.5 mm to 5 mm.

The inventors have also found that the “path length” of the hair is related to the preferred vibration frequency. Here, the path length is the length of the hair that is held between the inlet and the outlet that is vibrated within the device. With the above preferred ranges of vibration frequencies, the path length is preferably between 10 mm and 80 mm and for the most preferred vibration frequency of 40 Hz to 50 Hz, the path length is preferably between 15 mm and 30 mm. In the devices illustrated inFIGS. 1 and 6, the path length has been made larger than the width of the device by angling the heater plates in the manner shown. This allows the path length of the hair to be optimised for a given width of device.

In other preferred embodiments the vibration frequency is in the range of 10 Hz to 1 kHz, preferably in the range of 40 Hz to 100 Hz, and more preferably in the range of 60 Hz to 80 Hz.

As a general principle, ideally the hair is vibrated at or near its “resonant frequency”, in order to obtain maximum (or near-maximum) amplitude of movement of the hair. In this context, the resonant frequency of the hair is dependent on (a) the type of hair; (b) the amount and length of hair in the plenum chamber22; (c) the amount of water on the hair; and (d) the tension of the hair in the plenum chamber22.

Thus, the resonant frequency of the hair will vary from person to person, or even, for the same person, from use to use of the device. To allow for this, the dryer/styler device may optionally be provided with user controls (e.g. in the form of a user interface, e.g.68inFIG. 12) to enable the user to adjust the vibration frequency of the vibrating plate20, to suit the hair in question. Alternatively, the device may optionally be provided with a feedback circuit incorporating a sensor (66inFIG. 12) which measures the amplitude of movement of the hair, and a controller which adjusts (e.g. periodically) the frequency of the vibrations applied by the device, in response to the measured amplitude of movement of the hair, so as to maximise (or achieve a predetermined level of) the measured amplitude of movement of the hair.

Such a feedback system may be combined with the temperature control feedback system mentioned above. For example, a single microprocessor controller (62inFIG. 12) may serve as the controller for both the vibration frequency feedback control and the heater plate temperature feedback control.

Amplitude and Frequency of Vibrational Response of the Hair

With reference toFIGS. 6aand 6b, the vibrational response of the hair in the plenum chamber22due to vibration of the vibrating plate20(i.e. during the convection and vibration stage, S2) is illustrated. Because of resonant effects between the vibrating plate20and the hair, in response to vibration of the plate20at a given frequency, the amount of displacement of the hair in the plenum chamber22depends on the same factors (a) to (d) mentioned above, i.e. (a) the type of the hair; (b) the amount and length of hair in the plenum chamber; (c) the amount of water on the hair; and (d) the tension of the hair in the plenum chamber22. As shown, the vibrational response of the hair rapidly drops away close to the edges of the plenum chamber22(i.e. near to the heater plates24a-d).

The graph inFIG. 6balso illustrates the variation in air flow velocity (i.e. in respect of air flow32) with position, showing that it is substantially constant across most of the plenum chamber22, but rapidly drops away close to the edges of the plenum chamber22(i.e. near to the heater plates24a-d).

Second Exemplary Embodiment

FIG. 7aillustrates (schematically in plan view, and in transverse cross-section) a second embodiment of a combination hair dryer/styler device10a.FIG. 7bis an enlarged view of the transverse cross-section of the device10a. This device has a number of features in common with the first embodiment device10, as indicated by the use of like reference numerals, which need not be described again.

Key differences over the first embodiment include the provision of two vibrating plates20aand20b(rather than a single vibrating plate20) in the plenum chamber22, and the provision of a separate motor29(i.e. separate from the fan motor28) to drive the vibrating plates20a,20b. The motor29drives the vibrating plates20a,20bvia dedicated shafts (or so-called “flexi drive” connections)34aand34b, separate from the fan26. This allows the vibrating plates20a,20bto be operated and controlled independently of the operation of the fan26.

As shown in the transverse cross-section inFIG. 7b, another difference of the second embodiment device10arelative to the first embodiment device10is the provision of a unitary (rather than bifurcated) second arm14, broadly symmetrical with the first arm12and arranged to close in a clamshell-like manner about the length of hair40that is to be dried at any given time within the device10a. As with the first embodiment device10, the length of hair40is held between the respective first heater plates24a,24bof the first and second arms12,14, and also between the respective second heater plates24c,24dof the first and second arms12,14.

Moreover, as shown in the transverse cross-section inFIG. 7b, in the device10aof this second embodiment one of the vibrating plates (i.e. plate20b) may be mounted on the first arm12, within the plenum chamber22, whereas the other of the vibrating plates (i.e. plate20a) may be mounted on the second arm14, also within the plenum chamber22, and facing in the opposite direction to the first plate20b. The vibrating plates20a,20bact near each of the end nodes of the hair (the nodes being defined by the points where the hair is contacted (or gripped) by the heater plates24a-d), with the vibrating plates20a,20bpushing the hair40in synchronism with one another, in an alternating manner, in opposite directions to each other.

As shown in the transverse cross-section inFIG. 7b, the device10aof the second embodiment may also include supplementary heater plates21a,21b(with corresponding supplementary heater elements23a,23b) disposed within the plenum chamber22, in the centre of the opposing faces of the first and second arms12,14, to provide additional heating to the plenum chamber22and thus to the flow of air32and the length of hair40held within.

As also shown in the transverse cross-section inFIG. 7b, styling means42may be provided at the inlet and outlet of the device11a, through which the length of hair40passes, to impart specific styling processes on the hair as it is dried (such as combing).

Further, as illustrated in the plan view ofFIG. 7a, a diffuser44may be provided at the outlet of the plenum chamber22, to dissipate hot air expelled from the device. The diffuser44may also act to divert air towards the root of the hair on starting a new length of hair, when the device is closed.

Third Exemplary Embodiment

FIG. 8illustrates a third embodiment of a combination hair dryer/styler device10b(shown in transverse cross-section). This device10bis similar to the device10aof the second embodiment, as reflected by the use of like reference numerals, but with the heater plates24a-dthemselves being the vibrating members which impart vibration on the hair40in use. More particularly, the heater plates24a-dare driven (and thereby caused to vibrate) by dedicated shafts (or so-called “flexi drive” connections), similar to shafts34aand34bshown inFIG. 7a. The heater plates24a-dhave rotational movement to provide a “scrunching” effect on the hair during the drying/styling process, as the heater plates24a-dvibrate.

As illustrated, the device10bfurther comprises a supplementary heater element23embedded beneath the surface of the plenum chamber22and configured to provide additional heating to the plenum chamber22and thus to the flow of air32and the length of hair40held within.

Mechanisms and Techniques for Imparting Vibration to Wet Hair

The present work contemplates a variety of possible alternative mechanisms and techniques for imparting vibration to wet hair, to cause clumped hairs to move and separate.

FIG. 9aillustrates a first technique, as employed in the above-described first embodiment, whereby one or more vibrating plate(s)20is/are driven in a reciprocating manner by a cam35, at or near the midpoint of the length of hair40that is held between the heater plates24a-d. If more than one vibrating plate is used in this location, the plates may be mounted on opposite arms of the device, so as to act in opposite directions.

FIG. 9billustrates a second technique, as employed in the above-described second embodiment, whereby two vibrating plates20a,20bact near each of the end nodes of the hair (the nodes being defined by the points where the hair is contacted by the heater plates24a-d). The vibrating plates20a,20bare driven by a controller in synchronism with one another, so as to move in opposite directions to one other. That is to say, one vibrating plate (e.g.20a) moves away from its respective arm whilst the other plate (e.g.20b) moves towards its respective arm, and vice versa.

Other arrangements of one or more vibrating plates, or other vibrating members, may alternatively be used to impart vibration on the hair, as those skilled in the art will appreciate. For example, one or more rotating cam members or rods may be arranged to act directly on the hair, to impart vibrations directly to the hair, without the use of a vibrating plate.

As illustrated inFIG. 10a, the or each vibrating plate20(shown here in longitudinal cross-section) may have a linear or planar surface, as a result of which the hairs50that contact the vibrating plate typically move away from the surface of the plate in a direction X that is substantially parallel to the direction of vibrational motion Y of the plate (as indicated by the double headed arrows in the figure).

Whilst the plate geometry shown inFIG. 10ais effective in causing clumped wet hairs to move and separate, the variant shown inFIG. 10bhas been developed to further improve the separation of clumped wet hairs as a result of vibration of the vibrating plate20′. More specifically, vibrating plate20′ is formed with a nonplanar, ridged or contoured surface—for example having a jagged or saw-toothed profile as illustrated—as a result of which the hairs50that contact the vibrating plate are caused to move away from the plate in an initial direction X′ that is not parallel to the direction of vibrational motion Y of the plate, but rather is at an angle to the direction of motion of the plate. The hairs50may then return towards the plate via a curved or more chaotic/random path, as illustrated schematically in the figure by the dashed arrows. As a consequence of imparting greater motion to the hairs50in this manner, the geometry of the vibrating plate20′ is more effective than the geometry of the vibrating plate20′ shown inFIG. 10aat causing clumped wet hairs to move and separate.

Furthermore, as a consequence of this motion path of the hairs50, in this example the waste water separated from or evaporated from the hair has a tendency to move in the direction Z indicated by the large arrow in the figure (this direction Z effectively resulting from the asymmetric nature of each of the saw-toothed regions on the surface of the plate in this example). Naturally, this direction Z can be made to coincide with the direction of airflow32through the plenum chamber22, thereby increasing the efficiency with which water can be removed from the hair and expelled from the dryer.

FIGS. 11aand 11billustrate further alternatives for imparting vibration to the wet hair40. In these alternatives, a cam53is mounted for rotation with the rotating shaft55of the motor (not shown). InFIG. 11a, the cam53directly contacts and moves the hair40as it rotates and inFIG. 11b, the cam53acts on a reciprocating member57which contacts the hair40causing the hair to be moved. A spring biased cam follower59is also provided to hold the hair against the cam53or the reciprocating member57.

With regard to the techniques shown for example inFIGS. 9a, 9b, 10a, 10b, 11aand 11b, and also other possible arrangements of one or more vibrating plates (or other vibrating or rotating members), the or each vibrating plate (or other member) may be driven for example by any of the following mechanisms:an eccentric disc, driven by a rotary motora cam (e.g. together with a spring or a cam follower), driven by a rotary motora reciprocating wormdrive arrangementa crankshaft and a connecting rod, driven by a rotary motora reciprocating solenoid

Other mechanisms for imparting vibration to wet hair are also possible, as those skilled in the art will appreciate.

In general, it will be appreciated that the hair passes through the device in a first direction, and the means for imparting vibration are configured to vibrate the hair in a second direction transverse to the first direction. The second direction may be at an angle in the range of 35° to 145° relative to the first direction. In the presently-preferred embodiments the angle is approximately 90°.

Control Circuitry

FIG. 12shows an example of a control circuit60suitable for use in the devices10,10aand10bof the above-described embodiments.

The control circuit39includes a microprocessor62mounted on the printed circuit board assembly36, and configured to receive power from the power supply38. Although not expressly shown, it will of course be appreciated that the other electrical components within the circuit60are also configured to receive power from the power supply38. The microprocessor62is provided with a memory storing control logic, which is executed by the microprocessor62when carrying out its various functions. A user interface68is also connected to the microprocessor62, enabling the user to control the functions of the device.

The microprocessor62is connected to the above-described heater plate element(s)25(e.g.25a-d), the fan heater element(s)27and the fan motor28, and is configured to control these components (i.e. to regulate the power to these components and to cause them to function as described above). Optionally, as shown for example in the embodiments ofFIGS. 7/7aand8, one or more supplementary heater elements23may also be controlled by the microprocessor62.

As mentioned above, a moisture and/or temperature sensor64may optionally be provided in the plenum chamber22and/or at the inlet and/or outlet thereof. Signals representative of the sensed moisture level(s) or temperature(s) are supplied from the sensor64to the microprocessor62from which the microprocessor determines how wet or how dry the hair is that is being treated.

During use of the device10/10a/10b, the microprocessor62may be configured to increase the temperature of the outlet heater plate element(s)24and/or the fan heater element(s)27and/or the supplementary heater element(s)23(if provided), when the hair is dry to allow improved styling of the hair. The microprocessor62may also be configured to reduce the speed of operation of the fan motor28in response to the detected moisture level of the hair decreasing, thereby saving energy.

Conversely, if the microprocessor determines that the hair is wet (by processing the signals from the sensor64), for example due to movement of the device to a wetter section of hair, the microprocessor62may be configured to reduce the temperature of the heater plate element(s)24and/or the fan heater element(s)27and/or the supplementary heater element(s)23(if provided) in response, in order to prevent cavitation of water on the hair or denaturation of the hair. The microprocessor62may also be configured to increase the speed of operation of the fan motor28in response to the detected moisture level of the hair increasing.

Where temperature sensors are provided at both the inlet and the outlet of the device10, the microprocessor62can determine from the sensed temperature difference between the inlet and the outlet, which way round (orientation) the user is using the device. This orientation information can be used by the microprocessor62to control the thermal power applied to the heater elements24so that the hair at the inlet is heated less than the hair at the outlet. Alternatively, where the device10has a product applicator (for applying a hair product such as a hair gel or the like) at both the inlet and the outlet, the microprocessor24can use the orientation information to control the applicators so that, for example, only the applicator at the inlet is used to apply the hair product. Alternatively, where the applicators are able to apply different hair products, the microprocessor62can use the orientation information to select the hair product to be applied by each applicator—so that, for example, hair products that would benefit from being dispersed throughout the hair are applied at the inlet side of the device (prior to the vibrating or rotating member) and hair products that may be used to protect the hair from the high temperatures of the outlet heaters are applied by the applicator positioned towards the outlet of the device10(prior to the outlet heaters).

Further, a sensor66may optionally be provided in the plenum chamber22to measure the amplitude of movement of the hair40therein, in response to the applied vibration from the vibrating plate(s) or other vibrating member(s). The sensor66may be, for example, an optical sensor configured to detect the extent to which the vibrated hair moves across its “field of view”. A signal representative of the detected amplitude of movement is supplied from the detector64to the microprocessor62. With the aim of maximising (or achieving a predetermined level of) the measured amplitude of movement of the hair (e.g. by virtue of resonance) and thereby improving the efficiency of the drying process, the microprocessor62may be configured to adjust (e.g. periodically), in response to the measured amplitude of movement, the frequency of the vibrations applied to the hair40by the or each vibrating member—i.e. as a feedback process. This may be achieved by the microprocessor62adjusting the speed of operation of the fan motor28(if the vibrating plate(s)/member(s) are also driven by the fan motor28, as in the case of the device10of the first embodiment), or by adjusting the speed of operation of the vibrating member drive motor29(or the frequency of operation of the abovementioned solenoid(s) or other frequency drive means) if the vibrating plate(s)/member(s) are driven separately from the fan, as in the case of the device10aof the second embodiment.

Modifications and Alternatives

Detailed embodiments and some possible alternatives have been described above. As those skilled in the art will appreciate, a number of modifications and further alternatives can be made to the above embodiments whilst still benefiting from the inventions embodied therein. It will therefore be understood that the invention is not limited to the described embodiments and encompasses modifications apparent to those skilled in the art lying within the scope of the claims appended hereto.

For example, in some of the above embodiments, the device had a vibrating or rotating member (such as a vibrating plate) over which the hair was constrained to pass. As those skilled in the art will appreciate, multiple vibration or rotating members may be provided longitudinally within the device so that different hairs within the clump of hair that is drawn through the device are vibrated by different members.

In all of the embodiments described above, heating plates were provided symmetrically on either side of the plenum chamber. However, as those skilled in the art will appreciate, one or more heating plates may be provided on just one side of the chamber. In this case, the device can only be used to dry hair by passing the hair through the device in one direction.

In the above embodiments, heater plates were provided at the input side and the output side of the plenum chamber. However, as those skilled in the art will appreciate, it is not necessary that these plates are heated. The squeegeeing effect of the plates may be sufficient in some circumstances to dry the hair in combination with the vibrational drying. However, having at least one heated plate is preferred as it helps with the drying process.

Finally, as mentioned earlier, whilst the above embodiments include a fan or other means for generating a flow of air, alternative embodiments can be realised in which a fan or other means for generating a flow of air is not provided, instead relying on the vibration imparted to the hair (potentially in combination with the abovementioned squeegeeing effect) to cause the hair to dry.

In the second embodiment described above, a diffuser44was provided on the air outlet from the chamber. This allowed some of the air to be directed towards the roots of the user's hair during use. Is an alternative arrangement, air channels or vents may be provided through the side of one or both of the first and second arms12,14so that air drawn or blown through the chamber can pass out through these air vents towards the roots of the user's hair during use. Such an embodiment is illustrated schematically inFIG. 14, by the vents71provided in the arm12.

In the first embodiment described above, the arm14was bifurcated. In an alternative embodiment, the arm14may be bifurcated in the middle but both ends of the arm may be joined together.

Throughout the description and claims of this specification, the words “comprise” and “contain” and variations of the words, for example “comprising” and “containing”, means “including but not limited to”, and is not intended to (and does not) exclude other components, integers or steps.