ATTACHMENT FOR A HAIRCARE APPLIANCE

FIELD OF THE INVENTION

The present invention relates to an attachment for a hair care appliance, a hair care appliance such as a hairdryer or hot styling brush and an appliance comprising such an attachment.

BACKGROUND OF THE INVENTION

Blowers and in particular hot air blowers are used for a variety of applications such as drying substances such as paint or hair and cleaning or stripping surface layers. In addition, hot air blowers such as hot styling brushes are used to style hair from a wet or dry condition.

Conventionally such appliances are provided with an attachment which can be attached and detached from the appliance and changes the shape and velocity of fluid flow that exits the appliance. Such attachments can be used to focus the outflow of the appliance or to diffuse the outflow.

It is known in conventional appliances that increased and more concentrated airflow velocities cause significantly undesirable noise levels which reduces the user comfort. This presents a compromise between acceptable noise levels and drying performance.

The present invention mitigates this problem by introducing plate to the flow path but without changing the shape of the outflow from an appliance and without blocking the outflow.

SUMMARY OF THE INVENTION

According to a first aspect of the present invention there is provided an attachment for a hair care appliance, the attachment comprising an air inlet end for receiving an airflow from the appliance,

- an air outlet end for emitting the airflow from the attachment,
- a wall defining and extending about an airflow path between the air inlet end and the air outlet end,
- a plate located in the airflow path and configured to guide the airflow towards the airflow outlet end, wherein
- the plate is configured to divide the airflow path into two sections and
- the plate comprises a plurality of through holes extending between the two sections of the airflow path.

The perforations formed at the surface of the plate provide noise reduction by minimising stream-wise vortices over the surface of the plate and therefore reduce the turbulence-induced noise.

In a preferred embodiment, the through holes are chamfered. The holes with chamfered edges enable simple manufacturing methods to be used and improve manufacturing efficiency. Preferably the perforations are cylindrical or frustoconical, thus enabling desirable tooling and manufacturing capabilities.

Through-holes enable the pressure difference between the opposite sides of the plate to be substantially equalised and improve the airflow mixing. Thus, the improved mixing reduces turbulence-induced noise.

The diameter of the plurality of through holes is in the range from 1 to 3 mm. However, in a preferred embodiment the diameter of the plurality of through holes is in the range from 1.2 to 2.6 mm. The preferred diameter range enables optimum noise reduction while maintaining substantially undisturbed boundary layer between the plate and the airflow.

Preferably, the through holes are arranged in a plurality of rows and said plurality of rows extend orthogonal to the longitudinal axis of the attachment. This arrangement enables a balanced pressure equalisation between two opposite sides of the plate.

The through holes may be staggered in a variety of ways. However, in a preferred embodiment every one of the rows of through holes extending orthogonal to the longitudinal axis of the attachment is staggered with respect to its immediately adjacent row. This arrangement improves the pressure equalisation performance between two opposite sides of the plate while minimising disruption to the boundary layer between the plate and the airflow.

According to a second aspect of the present invention there is provided an attachment for a hair care appliance, the attachment comprising

- an air inlet end for receiving an airflow from the appliance,
- an air outlet end for emitting the airflow from the attachment,
- a wall defining and extending about an airflow path between the air inlet end and the air outlet end, and
- a plate located in the airflow path and configured to guide the airflow towards the air outlet end.

Preferably, the plate extends along a direction of airflow from the air inlet end towards the air outlet end.

The plate is configured to increase mixing of airflow and reduce the turbulent mixing noise caused by the eddy formations due to the mixing of air streams at the opposite sides of the plate. In order to enable this mixing of air streams at the opposite sides of the plate, the said plate is configured such that it cuts through the cross-section of the wall orthogonally and extends from proximate to the air outlet of the attachment to at least a portion of the length of the wall along the airflow path. Furthermore, the plate is configured to provide a basis for means to handle the attachment when the attachment is hot due to normal use.

Preferably, the plate comprises a non-linear edge proximate to the air outlet end. The non-linear edge may be at the air inlet end or air outlet end of the plate but preferably, the non-linear edge is located at the air outlet end. Thus, the non-linear edge increases the number of counter-rotating vortices at the air outlet end and enable reduction of turbulent mixing noise caused by the eddy formation due to the mixing of air streams at the opposite sides of the plate.

In a preferred embodiment, the non-linear edge of the plate is proximate to the airflow outlet and comprises a wave-shaped profile forming peaks and troughs. The non-linear edge of the plate is final point of contact between the airflow and the attachment. Therefore, it is expected that maximum noise generation due to eddy formations may occur proximate to the non-linear edge of the plate. Thus, the wave-shaped profile located at the non-linear edge of the plate provides improved noise reduction.

The wave shaped profile may be in the form of a variety of waveforms, including but not limited to sine wave, square wave, triangle wave and sawtooth wave. In a preferred embodiment, the wave shaped profile is curved and in the form of a sine wave. Curved profile of the non-linear edge further improves noise reduction efficiency of the noise reduction efficiency of the attachment.

In a preferred embodiment, the plate is substantially planar, and the non-linear edge of the plate extends substantially orthogonal to the central longitudinal axis of the attachment. The airflow forms a boundary layer on both sides of the plate starting from an inlet edge of the plate proximate to the airflow inlet and towards the non-linear edge of the plate. This boundary layer is parallel to the longitudinal axis of the attachment and the airflow exiting from the air outlet starts forming vortices upon leaving the surface of the plate. The peaks and troughs made along the non-linear edge of the plate induce stream-wise vortices into the shear layer closer to the surface of the plate, leading to increased mixing of the airflow. Thus, the air pressure difference at the opposite sides of the plate can be reduced substantially and the noise levels caused by this pressure difference is reduced accordingly.

In a preferred embodiment, the non-linear edge when viewed in a plane orthogonal to the plate, has a curved profile. Attachments for hair dryers are common household items and therefore safety measures must also be considered. The curved profile of the non-linear edge provides safe handling for the attachment while enabling increased mixing of the airflow.

In a preferred embodiment, the non-linear edge is formed as part of the plate. Absence of assembly sections enable improved manufacturing capabilities and reduce vortex-inducing surface features which may cause undesirable disruptions in the boundary layer and increase the noise levels.

Preferably, the plate is configured to divide the airflow path into at least two sections. The plate is configured to guide an upper airflow path over a first surface of the plate and a lower airflow path over a second surface of the plate. Thus, the plate divides the airflow proximate to the airflow inlet and reintroduces the separated upper and lower airflow paths proximate to the airflow outlet with reduced turbulence and noise level.

Preferably, the palate divides the cross-sectional area of the airflow path into two equal sections. Equal cross-sectional areas minimise the pressure difference between the upper and lower airflow paths. Thus, the noise reduction efficiency of the teeth at the first edge of the plate is improved.

Preferably, the wall is disposed about the longitudinal axis of the attachment. Position of the plate enables improved assembly for the desired result of dividing the airflow path into equal cross-sectional areas and thus improving noise reduction efficiency.

In a preferred embodiment of the attachment, the wall comprises an annular wall extending around the longitudinal axis of the attachment, preferably located such that the centre of the annular wall lies on the longitudinal axis of the attachment. Alignment of the centre of the annular wall with the longitudinal axis of the attachment is desirable for ease of manufacturing and assembly.

Preferably, at least a portion of the wall is tapered. The wall defines outer boundaries of the airflow path. Accordingly, depending on the end-use requirements, the tapering may be towards or away from the longitudinal axis of the attachment.

In a preferred embodiment, the wall tapers inwardly towards the longitudinal axis of the attachment, from air inlet end towards the air outlet end. The wall and the plate guide the airflow towards the air outlet end thus tapering of the said wall enables the control of cross-sectional area of airflow path which directly affects the airflow speed.

In a preferred embodiment the angle of taper of the wall varies between the inlet end and the outlet end. The tapering of the wall enables increased airflow speed and thus improve drying capabilities of the attachment. From the air inlet end towards the air outlet end, the cross-sectional area of the airflow path decrease, in order to increase the airflow rate to a desired level. However, this also increases the risk of creating a turbulent airflow and thus increased noise levels. Varying of the tapering of the wall enables smooth transition from a first cross-sectional area at the air inlet end to the second cross-sectional area at the air outlet end, with minimal disturbance to the airflow. Consequently, the airflow is kept substantially laminar along the airflow path and noise levels can be kept under control.

In a preferred embodiment, the attachment comprises an external wall surrounding said wall of the attachment. The external wall provides a surface for the user to hold the attachment. The air gap between the external wall and the said wall that defines the airflow path also provides a barrier between the heated elements of the attachment and the user. Thus, the external wall acting as a cool wall improves the end user experience.

As previously disclosed, in order to enable the mixing of air streams at the opposite sides of the plate that is located within the airflow path, the said plate is configured such that it cuts through the cross-section of the wall orthogonally and extends from proximate to the air outlet of the attachment to at least a portion of the length of the wall along the airflow path. Accordingly, the plate also cuts through the cross-section of the external wall orthogonally and extends from proximate to the air outlet of the attachment to at least a portion of the length of the external wall along the airflow path. Furthermore, the plate may be cutting through the cross-section of the external wall orthogonally and may extend further outside the cross-sectional area of the external wall. Thus, the portions of the plate extending outside the external wall may provide means for holding the attachment.

In a preferred embodiment, the wall and the external wall each comprises a plurality of retention members configured to retain the wall within the external wall. The retention members may be snap-fit elements and enable removable attachment.

Preferably, the plate comprises a pair of members located at the opposite ends of the non-linear edge which are gripped by the user when attaching the attachment to the hair care appliance. The said pair of members are configured to increase the surface area of the plate that is in contact with the surrounding environment and provide a cool surface for the user to grip. Said holding member enables, comfortable handling of the attachment, especially after use, when the attachment is hot. The holding member is preferably a hollow profile formed as part of the plate. Furthermore, the holding member is configured not to obstruct the airflow path. Preferably, the holding member is a hollow cylinder, providing increased structural resilience in case of accidental dropping of the attachment.

Preferably, the attachment comprises a seat configured to accommodate an RFID tag. In a preferred embodiment the seat is located on external wall. Furthermore, an RFID cap may be used to cover the RFID tag and prevent dislocation of the RFID tag in use.

Preferably, the air inlet end is adapted to receive part of the appliance. Thus, the user may align the inlet end of the attachment with an outlet end of the appliance for simple assembly suitable for use.

Preferably, the attachment comprises a magnet attached to the wall for securing the attachment to the appliance. With the aid of magnetised attachment, the assembly efficiency of the attachment and the appliance is increased thus improving end-user comfort.

It will be clear to the skilled person that the features described above in connection with the first aspect of the invention are equally applicable to the second aspect of the invention, and vice versa.

BRIEF DESCRIPTION OF THE DRAWINGS

Preferred features of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which:

FIG. 1 is a left side, front perspective view, from above, of an attachment;

FIG. 2 is a right side, rear perspective view, from above, of the attachment;

FIG. 3 is a top view of the attachment;

FIG. 4 is a side view of the attachment;

FIG. 5 is a bottom view of the attachment;

FIG. 6 is a left side, front exploded view of the attachment;

FIG. 7 is a right side, rear exploded view of the attachment;

FIG. 8a is a side sectional view taken along line A-A in FIG. 3;

FIG. 8b is a side sectional view taken along line B-B in FIG. 3;

FIG. 9 is a left side, front perspective view, from above, of an example of a hair dryer to which the attachment and the alternative attachment may be connected.

DETAILED DESCRIPTION OF THE INVENTION

FIGS. 1 to 5 are external views of an attachment 10. The attachment comprises an air inlet 12 for receiving airflow from an airflow outlet end of a hair dryer and an air outlet 14 for enabling the airflow to exit the attachment. With reference also to FIGS. 6 and 7, the air inlet 12 is generally annular in shape, and is in the form of an aperture located at the air inlet end 16 of a wall 18. The wall 18 has an air outlet end 20 which is narrower than the air inlet end 16, and a tapering wall 18 extends between the air inlet end 16 and the air outlet end 20. Tapering of the wall 18 may be inwardly, outwardly or a combination thereof along an airflow path 22 defined by the wall 18. However, in this embodiment, the tapering of the wall 18 is inwardly towards the longitudinal axis C of the attachment 10 along at least a portion of the airflow path 22 from the air inlet end 16 to the air outlet end 20.

As illustrated in FIGS. 8a and 8b, the tapering wall 18 defines the airflow path 22 through which the airflow passes within the attachment 10. The tapering wall 18 is arranged to guide the airflow from the air inlet 12 to air outlet 14 of the attachment 10 along an airflow direction D, as illustrated in FIG. 4, directly towards the air outlet 14.

With reference to FIG. 7, the wall 18 comprises an annular inlet channel 24 for receiving airflow from the air inlet 12 and from which the airflow is guided along the airflow path 22 towards the air outlet end 20.

With reference to FIGS. 1 and 2, a plate 26 is disposed along the airflow path 22 and is parallel to the longitudinal axis C of the attachment 10. The plate 26 is configured to guide the airflow towards the air outlet 14 and has generally a flat surface. Furthermore, the end of the boundary layer between the airflow passing through the airflow path 22 and the plate 26 is along the first edge 32 of the plate 26.

As presented particularly in FIGS. 1 and 8a, the plate 26 comprises a plurality of undulations in the form of peaks 28 and troughs 30 along the first edge 32 of the plate 26. The first edge 32 of the plate 26 is proximate to the airflow outlet 14 of the attachment 10. Accordingly, these undulations enable improved mixing of the airflow passing through the airflow path 22 and emitted from the air outlet 14. Compared to a straight edge, the undulations increase the length of the first edge 32 of the plate 26. This also increases the number of points at which the air streams at the opposite sides of the plate 26 can meet. As such, the number of counter-rotating vortices increase with the increased interaction between the air streams at the opposite sides of the plate 26. It will be clear to the person skilled in the art that the introduction of counter-rotating vorticity into an airflow through internal undulations allows for significant noise reduction with thrust augmentation or minimal airflow rate loss.

The peaks 28 and throughs 30 of the undulations at the first edge 32 of the plate 26 may be arranged such that the number, position and dimensions of the peaks 28 and troughs 30 may vary and the number of peaks 28 may not be equal to the number of troughs 30. In this embodiment, the peaks 28 and troughs 30 are laterally equally spaced along the first edge 32 of the plate 26. Furthermore, the peaks 28 and troughs 30 form a regular shape resembling a sine wave along the first edge 32 of the plate 26. It will be clear to the person skilled in the art that the undulations may be extend in a variety of directions. In this embodiment the teeth 28 of the undulations extend parallel to the longitudinal axis C of the attachment 10 thus minimising the disturbance on the boundary layers at the opposite sides of the plate 26.

With reference to FIGS. 1, the peaks 28 and the troughs 30 of the plate 26 may be formed as a cut out. In this embodiment and with reference to FIG. 8b, the cut-out edge along the first edge 32 is rounded thus providing a curved surface connection between the opposite sides of the plate 26.

With reference to FIGS. 1 and 4, the plate 26 comprises a plurality of perforations 34. It will be clear to the person skilled in the art that the type, size and arrangement of the perforations 34 may vary depending on technical requirements and manufacturing capabilities. Furthermore, the perforations 34 may comprise a plurality of blind holes. In this embodiment, the perforations 34 comprise a plurality of through holes and enable airflow communication between the opposite sides of the plate 34. Furthermore, in this embodiment the perforations 34 are through holes with a diameter of 2 mm and comprise rounded edges.

With reference to FIG. 8a, the perforations 34 may be arranged in an equally spaced array. The perforations 34 may also be aligned in both directions parallel and perpendicular to the longitudinal axis C. In this embodiment, the perforations are aligned in the direction perpendicular to the longitudinal axis C. However, in the direction parallel to the longitudinal axis, the perforations 34 are offset, while maintaining the equally spaced array formation. The perforations 34 may be distributed over the entirety of the planer surface of the plate 26. In this embodiment, the perforations 34 are distributed on at least a portion of the planer surface of the plate 26. Accordingly, the plate 26 comprises a solid plate section 36, free from perforations 34.

With reference to FIGS. 1 and 8a, the perforations 34 may extend in a variety of directions. In this embodiment, the perforations extend in a direction substantially perpendicular to the longitudinal axis C of the attachment 10 and the planer surface of the plate 26.

With reference to FIGS. 3 and 8b, the plate 26 divides the airflow path into at least two sections. In this embodiment, the plate 26 divides the airflow path into two equal sections.

As airflow passes through the attachment 10, the airflow guided by the plate 26, boundary layers are formed on the opposite sides of the plate 26. The plurality of perforations 34 enable airflow between the opposite sides of the plate 26 and thus minimise the pressure difference between the opposite sides of the plate 26. Accordingly, the turbulence induced noise due to pressure difference is minimised upon the emission of the airflow from the attachment 10.

With reference to FIG. 1, the plate 26 comprises at least one holding member 38 configured to provide a holding surface. When in use, the holding member 38 is configured to stay relatively cooler compared to the rest of the plate 26. It will be clear to the person skilled in the art that the holding member 38 may be in a variety of shapes and sizes. Furthermore, the holding member 38 may extend in a variety of directions, with reference to the plate 26. In this embodiment, the plate 26 comprise a pair of holding members 38 and extend parallel to the longitudinal axis C of the attachment. Furthermore, in this embodiment, the holding members 38 are in the form of a hollow cylinder

With reference to FIGS. 6 and 7, the attachment 10 further comprises an external wall 40 and the external wall 40 surrounds the wall 18 of the attachment 10. In normal use, the air passing through the attachment 10 increases the temperature of the wall 18. As illustrated in FIG. 8b, there is provided an air gap 42 between the wall 18 and the external wall 40 for isolation purposes and improves the end user comfort.

With reference to FIGS. 7, 8a and 8b, the wall 18 comprises at least one support member 44, located within the airflow path 22. The support member 44 further comprises at least one support rib 46 extending across the airflow path 22 within the inlet channel 24. The support member 44 is fixed to the wall 18 via the support rib 46 and provides a contact point between the wall 18 and the plate 26. In this embodiment there is a single support member 44 and located proximate to the longitudinal axis C of the attachment 10.

With reference to FIGS. 7 and 8a, the external wall 40 further comprises an RFID slot 48 located at on the outer surface of the air inlet channel 24, suitable for receiving an RFID tag 50. The purpose of the RFID tag 50 is to alert a control circuit of a hair dryer 200 regarding the type of attachment, i.e. a smoothing nozzle attachment 10 or other suitable attachments, being used. The control circuit of the hair dryer 200 may then adjust relevant settings such as air temperature and airflow rate accordingly. The RFID tag 50 further comprises an RFID tape 52 and the RFID tag 50 is seated in the RFID slot with this RFID tape 52 in between. An RFID cap 54 is provided to complete the RFID tag housing.

A variety of combinations of the features defined above may be applied to the attachment 10. The components of the attachment 10 may comprise a variety of materials including but not limited to metal, plastic, carbon fibre or any combination thereof. Each of the components of the attachment 10 is formed from a plastic material. In this embodiment the components are formed from glass filled nylon.

To assembly the attachment 10, the plate 26 is first positioned along the central axis C located within the airflow path 22 defined by the wall 18 such that the plate 26 rests on the support member 44. The support member 44 comprises an assembly aperture 56. The plate 26 further comprises a fastening screw receptacle 58 and is configured to receive a fastening screw 60. When the plate 26 is resting on the support member 44, the fastening screw receptable 58 is aligned with the longitudinal axis C and the assembly aperture 56. The fastening screw 60 goes through the assembly aperture 56 and fixes the plate 26 via the fastening screw receptacle 58.

The external wall 40 has an inner surface comprising at least one assembly guide 62 and at least one retention member 64. In this embodiment there is a plurality of assembly guides 62 equally angularly spaced about the longitudinal axis C of the attachment 10 and a plurality of retention members 64 equally angularly spaced about the longitudinal axis C of the attachment 10. The wall 18 has an outer surface comprising at least one further assembly guide 66 and at least one further retention member 68. In this embodiment there is a plurality of further assembly guides 66 equally angularly spaced about the longitudinal axis C of the attachment 10 and a plurality of retention members 68 equally angularly spaced about the longitudinal axis C of the attachment 10.

The angular position of further assembly guides 66 correspond to the angular position of the assembly guides 62 and upon assembly the wall 18 is urged to the suitable angular position when assembled with the external wall 40. Similarly, the angular position of the plurality of further retention members 68 correspond to the angular position of the plurality of retention members 64. The retention members 64 and the further retention members 68 form a mating connection for example including but not limited to snap-fit, interference fit, screw and bolt fastening, ultrasonic welding, heat welding, solvent bonding or a combination of one or plurality of different methods.

The attachment 10 further comprises a coupling means 70 located at the air inlet end 16 of the wall 18. Coupling means 70 may be configured to enable a variety of coupling methods for example including but not limited to interference fit, screwing, magnetised coupling etc. In this embodiment the coupling means 70 is a magnet and configured to enable magnetised coupling of the attachment 10 to a hair dryer 200, more specifically to an airflow outlet end 202 of the hair dryer 200.

Whilst particular examples and embodiments have been described, it should be understood that various modifications may be made without departing from the scope of the invention as defined by the claims.

ATTACHMENT FOR A HAIRCARE APPLIANCE

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