FIELD OF THE INVENTION

The present invention relates to an attachment for a hair care appliance, in particular for 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.

Removable attachments for hairdryer can have several different uses. The usually circular flow exiting the hairdryer can be concentrated and flattened using a concentrator nozzle/attachment or it can be expanded and slowed by a diffuser. The different types of attachment dry the hair at different speeds with different flow rates enabling different styles to be created.

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 a noise attenuating member to the flow path but without changing the shape of the outflow from an appliance and without blocking the outflow. SUMMARY OF THU INVENTION

The present invention provides 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 for the airflow, a noise attenuation member surrounded by the wall wherein the noise attenuation member is configured to guide the airflow along at least part of the airflow path.

Preferably, the noise attenuation member comprises a perforated wall. Perforations on the perforated wall of the noise attenuation member aid in decoupling the sound waves from the airflow along the airflow path. These perforations may comprise circular apertures.

The perforated wall is preferably disposed about the longitudinal axis of the attachment. During normal use of the attachment, it is desirable to introduce the airflow to the perforated wall and therefore the noise attenuation member in an efficient manner, while maintaining the compactness of the attachment. Therefore, centrally placed perforated wall and noise attenuation member enables this compact assembly.

Furthermore, the perforated wall preferably comprises an annular wall, located such that the centre of the perforated wall lies on the longitudinal axis of the attachment. While it is the aim of this invention to reduce undesirable noise levels, it is equally important to maintain required airflow speeds radially as well as along the airflow path, throughout the attachment. Therefore, use of an annular wall as the airflow accepting surface of the noise attenuation member enables this passive regulation capability to the attachment.

In order to decouple the sound waves from the airflow, the surface of the perforated wall of the noise attenuation member is preferably arranged to receive the airflow with an incidence angle of less than 90 degrees. This angle may vary from the first incidence point to the ait outlet end, depending on the curvature profile of the perforated wall. However, preferably the perforated wall tapers outwardly towards the air outlet end. Furthermore, tapering of the perforated wall enables control of airflow path and air outlet end. Accordingly, the noise attenuation member guides the airflow with minimum airflow speed loss and optimum sound wave decoupling.

Perforations may comprise a plurality of holes. Preferably the perforations are cylindrical or frustoconical, thus enabling desirable tooling and manufacturing capabilities. Furthermore, the plurality of holes comprises a plurality of blind holes. In a preferred embodiment, the plurality of holes comprises a plurality of through holes. The plurality of holes enables the decoupled sound waves to propagate away from the airflow thus reducing the sound waves carried by the airflow to the airflow outlet end. Accordingly, the noise generated by the airflow exiting the attachment can be further controlled.

The diameter of the plurality of holes is in the range from 1 to 3 mm. However, in a preferred embodiment the diameter of the plurality of holes is in the range from 1.2 to 1.6 mm. The preferred diameter range enables optimum noise attenuation while maintaining substantially undisturbed boundary layer between the perforated wall and the airflow.

The through holes may extend in a variety of directions. Preferably, the through holes extend in a direction substantially perpendicular to the longitudinal central axis of the attachment. During normal use of the attachment, boundary layers may occur between the perforated wall and the airflow by nature. This boundary layer occurs in the immediate vicinity of the bounding surface, the perforated wall of the noise attenuation member, and defines the airflow path proximate to the perforated wall. Disturbances on the boundary layer, caused by features such as abrupt changes in the surface profile or turbulence inducing features extending from the surface may create a turbulent airflow around the perforated wall, thus increasing the noise levels generated by the airflow. In contrast, the sound waves propagate irrespective of the airflow path, in all directions. Accordingly, in the preferred embodiment of the present invention, the direction of the through holes is arranged such that the openings of the through holes enable minimum boundary layer disturbance on the airflow while enabling propagation of the sound waves away from the airflow path. Furthermore, the noise attenuation member comprises a sound-dampening material. Sound waves may propagate through gas, liquid or solid mediums. Accordingly, introducing a material with enhanced sound-dampening properties to the noise attenuation member further improves noise attenuation performance of the attachment.

The sound-dampening material may comprise a variety of materials such as but not limited to carbon fibre reinforced polymer (CFRP) felt, aerogel fibre or graphite fibre. In a preferred embodiment, the sound dampening material is an acoustic felt material comprising wool felt. Alternatively the sound dampening material is an acoustic foam; a suitable material is Basotect® a melamine resin foam which combines temperature resistant properties with sound adsorption. Wool felt provides optimum sound-dampening properties while maintaining desirable resistance against high operation temperatures. Wool felt is also a widely available and cheap material which enables the manufacturing process to be practical and financially viable.

In an alternative embodiment, the sound-dampening material may comprise a metal mesh layer. Furthermore, the metal mesh may comprise a stainless-steel mesh layer. The metal mesh comprises aperture size in the range from 0.005 to 0.02 mm. In a preferred embodiment, the metal mesh layer comprises aperture size of 0.005 mm.

In a further alternative embodiment, the sound-dampening material comprises a combination of a metal mesh and an acoustic felt material. In a preferred embodiment, the sound dampening material may be located between the perforated wall and the cap. The metal mesh layer may be located between the perforated wall and the acoustic felt material. Furthermore, in a preferred embodiment, the acoustic felt material may be located between the metal mesh layer and the cap of the attachment. However, it will be clear to a skilled person that the order in which the sound dampening material is arranged may be different.

In a preferred embodiment, the perforated wall is disposed between the air inlet end and the sound-dampening material. Sound-dampening materials generally have porous structure and therefore comprise aerodynamically undesirable surfaces. Thus, the perforated wall provides a boundary layer for the airflow while enabling the decoupled sound waves to interact with the sound-dampening material through the perforations.

Preferably, the sound-dampening material is surrounded by the perforated wall. Accordingly, the sound-dampening material is positioned such that the perforated wall forms a seat for the sound-dampening material to sit on. This enables practical assembly of the noise attenuation member and the attachment.

In another preferred embodiment, the noise attenuation member comprises a cap and the sound-dampening material is disposed between the perforated wall and the cap. The cap provides a fastening means to contain the sound-dampening material against the pressure created by the airflow through the perforations of the perforated airflow.

Preferably, the perforated wall and the cap each comprises a plurality of retention members configured to retain the sound dampening material within the noise attenuation member. Especially in the embodiments with through-holes as perforations of the perforated wall, the pressure created by the airflow may cause the sound-dampening material to be displaced or undesirably move between the perforated wall and the cap. This movement may create additional noise or reduce the efficiency of the noise attenuation provided by the sound-dampening material. Accordingly, the retention members secure the sound dampening material upon assembly of the noise attenuation member and ensure that there is no undesirable displacement of the sound-dampening material when the attachment is in use.

In another preferred embodiment, 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. This alignment is desirable for ease of manufacturing and assembly. Preferably, at least a portion of the wall is tapered. The wall also defines the airflow path. Accordingly, depending on the end-use requirements, the tapering may be towards or away from the central axis of the attachment.

Furthermore, at least a portion of the wall is preferably tapered outwardly away from the longitudinal axis of the attachment towards the outlet end. The wall and the perforated wall guide the airflow towards the air outlet end thus tapering of these two features enable the control of cross-sectional area of airflow path.

In a preferred embodiment, the angle of taper of the wall varies between the inlet end and the outlet end. From the airflow inlet end towards the airflow 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.

Preferably, the wall and the noise attenuation member are shaped such that the cross- sectional area of the airflow path, as measured perpendicular to the longitudinal axis of the attachment, decreases from the inlet end to the outlet end. By determining the cross- sectional area of the airflow path from the air inlet towards the air outlet, it is possible to regulate the airflow rate and thus the amount of noise generated by the airflow. The cross- sectional area of the airflow path at the outlet end may be in the range from 300 to 400 mm2. In a preferred embodiment of the present invention, the cross-sectional area of the airflow path at the outlet end is in the range from 340 to 360 mm2.

The attachment preferably 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.

Preferably, the wall comprises at least one support member located on a surface of the wall which faces the external wall, and each configured to provide a contact point between the wall and the external wall. These support members enable the external wall to deform while preventing the said deformation to be transferred to the wall of the attachment defining the airflow path. As previously discussed, prevention of any disturbance to the airflow path enables the improved control of airflow and noise levels when the attachment is in use.

Preferably, the wall comprises a seat configured to accommodate an RFID tag. The inlet end of the attachment is preferably adapted to receive part of the appliance.

Preferably, the attachment comprises a magnet attached to the wall for securing the attachment to the appliance.

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:

Figure 1 is a left side, front perspective view of an attachment 10;

Figure 2 is a right side, rear perspective view of the attachment 10;

Figure 3 is a side view of the attachment;

Figure 4 is a bottom view of the attachment;

Figure 5 is a left side, front exploded view of the attachment;

Figure 6 is a right side, rear exploded view of the attachment;

Figure 7a is a side sectional view taken along line A-A in Figure 3;

Figure 7b is a side sectional view taken along line B-B in Figure 3;

Figure 8 is a left side, front perspective view of an alternative attachment 100;

Figure 9 is a right side, rear perspective view of the alternative attachment 100; Figure 10 is a side view of the alternative attachment;

Figure 11 is a bottom view of the alternative attachment;

Figure 12 is a left side, front exploded view of the alternative attachment;

Figure 13 is a right side, rear exploded view of the alternative attachment;

Figure 14a is a side sectional view taken along line A-A in Figure 11;

Figure 14b is a side sectional view taken along line B-B in Figure 11; and

Figure 15 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.

DFTATT ED DESCRIPTION OF THE IW M I

Figures 1 to 4 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 to figures 5 and 6, 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 16 has an air outlet end 20 which is larger than the air inlet end 16, and an outwardly tapering wall 18 extending between the air inlet end 16 and the air outlet end 20.

As illustrated in figures 7a and 7b, the tapering wall 18 defines an 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 as illustrated in figure 1, directly towards the air outlet 14.

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.

A noise attenuation member 26 is surrounded by the wall 18 and disposed about the longitudinal axis C of the attachment. The noise attenuation member 26 is configured to guide the airflow towards the air outlet 14 and is generally conical in shape. The noise attenuation member 26 comprises a perforated wall 28 which further defines the airflow path and guides the airflow towards the air outlet end 20. The perforated wall 28 is an annular wall and tapers outwardly towards air outlet 14.

The perforated wall 28 comprises an array of perforations 30 through which sound waves can be emitted. The perforations 30 have the same size and shape. Each of these perforations 30 is circular in cross-section. Each of the perforations 30 may be cylindrical in shape, but in this embodiment each of the perforations 30 is frustoconical in shape, tapering inwardly from the external surface of the perforated wall 28 towards the internal surface of the perforated wall 28. At the external surface of the perforated wall 28, each of the perforations 30 has a diameter which is in the range from 1 to 3 mm. However, in this embodiment the diameter of perforations is in the range from 1.2 to 1.6 mm.

The perforations 30 may be arranged in a plurality of arrays. Within each array, the perforations 30 are regularly spaced. The spacing between neighbouring perforations in each array is in the range from 0.5 to 2 mm. In this embodiment the perforations 30 in each array are arranged such that the perforations are aligned along the longitudinal axis C of the attachment.

With reference to figure 7b, the perforations 30 extend in a direction substantially perpendicular to the longitudinal central axis C of the attachment 10. Furthermore, the perforations 30 may comprise a plurality of blind holes. However, in this embodiment, the perforations 30 comprise a plurality of through holes extending in a direction substantially perpendicular to the longitudinal central axis C of the attachment 10.

With reference to figures 5, 6, 7a and 7b, the noise attenuation member 26 comprises a sound dampening material 32. The sound dampening material 32 is disposed between the perforated wall 28 and a cap 34. It will be clear to the skilled person that a variety of materials or combination of a plurality of materials may be used as a sound dampening material 32. In this embodiment, the sound dampening material 32 is an acoustic felt material disclosed and secured between the perforated wall 28 and the cap 34. As airflow passes through the attachment 10, the airflow passing around the noise attenuation member 26 is guided by the boundary layer formed on the surface of the perforated wall 28. To reduce the noise generated by the airflow, the perforations 30 act as decoupling means to decouple sound waves from the airflow. Furthermore, the direction of the perforations 30 enable minimum disturbance on the boundary layer and the airflow speed at the air outlet 14.

With reference to figures 5 and 6, the perforated wall and the cap each comprises a plurality of retention members 36 and 38. Upon assembly, the retention members 36 and 38 secure the sound dampening material 32 and prevent it from undesirable movement in normal use of the attachment 10.

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. There is provided an air gap 42 between the wall 18 and the external wall 42 for isolation purposes and improves the end- user comfort.

With reference to figures 5 and 6, the wall 18 further comprises at least one support member 44 and at least one external wall fixing member 46 located on an outside surface of the wall 18 which faces the external wall 42 when assembled. The support member 44 provides a contact point between the wall 18 and the external wall 40, in addition to the external wall fixing members 46. The support member 44 is a deformable member and recovers to its initial state once the applied pressure is removed. In this embodiment, there is a plurality of support members 44 equally angularly spaced about the longitudinal axis C of the attachment 10.

With reference to figure 7b, the wall 18 further comprises an RFID slot 47 located at on the outer surface of the air inlet channel 24, suitable for receiving an RF ID tag 48. The RFID tag 48 further comprises an RFID tape 49 and the RFID tag 48 is seated in the RFID slot 47 with this RFID tape 49 in between. The purpose of the RFID tag 48 is to alert a control circuit of a hair dryer 200 regarding the type of attachment, i.e. a rough dryer attachment 10 or a gentle dryer attachment 100, being used. The control circuit of the hair dryer 200 may then adjust relevant settings such as air temperature and airflow rate accordingly.

The features defined for the attachment 10 similarly apply to the alternative attachment 100. Each of the components of the attachments 10 and 100 is formed from a plastic material. In these embodiments the components are formed from glass filled nylon.

To assemble the attachments 10 and 100, the sound dampening material 32 is first located on the perforated wall 28 so that the sound dampening material 32 rests on the inner surface of the perforated wall 28. The sound dampening material 32 comprises cut-out sections 50 and these cut-out sections align with the plurality of retention members 36 located on the inner surface of the perforated wall 28. In this embodiment, the plurality of retention members 36are arranged equally angularly spaced about the longitudinal axis C of the attachment 10 and 100. The cap 34 is then located along the periphery of the perforated wall 28 proximate to the air outlet 14. Accordingly, the outer periphery of the cap 34 sits on the outer periphery of the perforated wall 28. In this embodiment the fixing is done by ultrasonic welding. It would be obvious to the skilled person that other fixing methods such as gluing or snap-fit arrangements can be used. The assembly of perforated wall 28, sound dampening material 32 and the cap 34 forms the noise attenuation member 26.

The noise attenuation member 26 is then positioned along the central axis C on an assembly seat 54 of the wall 18. The assembly seat 54 comprises an assembly aperture 56 The perforated wall 28 further comprises a fastening screw receptacle 58 and is configured to receive a main fastening screw 60 which goes through the assembly aperture 56 and fixes the noise attenuation member 26 to the wall 18.

The external wall 40 has an inner surface comprising a plurality of assembly supports 62. Each of the assembly supports 62 comprises a peripheral assembly aperture 64. The external wall fixing members 46 of the wall 18 further comprises a plurality of peripheral fastening screw receptacles 66 arranged equally angularly spaced about the longitudinal axis C of the attachment 10 and 100. The peripheral fastening screw receptacles 66 are configured to receive peripheral fastening screws 68 which go through the peripheral assembly apertures 64 and secures the wall 18 to the peripheral assembly supports 62 of the external wall 40.

Accordingly, the assembly of the attachments 10 and 100 is completed by securing the noise attenuation member 26 to the wall 18 and then securing the wall 18 to the external wall 40. Furthermore, an RFID cap 69 is provided to cover RFID tag 48.

In use the attachment 10,100 is attached to the airflow outlet end 202 of a hair dryer 200. For example, the attachment 10, 100 may be attached to the hair dryer by a magnet 70 located at the air inlet end 16 of the wall 18.

With reference to figures 8 to 14, any features defined for attachment 100 which are equivalent to the features defined for attachment 10 have the same reference numerals. Whilst 10 and 100 have the same features of noise attenuation, the outlet profile 72 of the attachment 10 and the outlet profile 172 of the attachment 100 are different. More specifically with reference to figures 3 and 7b, the outlet profile 72 of the attachment 10 is configured to emits the airflow in a direction D tapering inwardly towards the longitudinal axis C of the attachment. With reference to figures 10 and 14b, the outlet profile 172 of the attachment 100 is configured to emit the airflow in a direction D’ tapering outwardly away from the longitudinal axis C of the attachment.

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.