Field of the Invention

The present invention relates to a haircare appliance, and an attachment for a haircare appliance.

Background of the Invention

Haircare appliances are typically used to dry and style hair. Where haircare appliances are used to style hair to create a smooth appearance, the presence of shorter or broken hairs, sometimes referred to as flyaways, may impact on the desired smooth appearance.

Summary of the Invention

According to a first aspect of the present invention there is provided an attachment for a haircare appliance, the attachment comprising an air inlet, an air outlet, a curved surface adjacent to and downstream of the air outlet, and a rib positioned such that the rib interacts with airflow exiting the air outlet to align the airflow exiting the air outlet.

The attachment according to the first aspect of the present invention may be advantageous as the attachment comprises a curved surface adjacent to and downstream of the air outlet, and a rib for interacting with airflow exiting the air outlet. The rib is arranged for aligning airflow exiting the air outlet before the airflow flows across the curved surface.

The attachment according to the first aspect of the present invention may be advantageous as the inventors of the present application have determined that directing airflow across the curved surface may generate a negative pressure region adjacent to the curved surface which attracts long hairs toward the curved surface, with the airflow interaction with hair also pushing shorter hairs away from the curved surface. This may result in shorter hairs being pushed through the longer hairs, for example through the longer hairs toward the side of hair facing a user’s head, such that a smooth finish is provided.

The attachment according to the first aspect of the present invention may be advantageous as the inventors of the present application have determined that the rib may align airflow to provide a more laminar airflow across the curved surface which may generate a greater pressure difference between the negative pressure region and ambient air and thus help to attract long hairs toward the curved surface. As airflow is turned, the airflow typically separates and thus becomes more turbulent. The inventors of the present application have determined that the rib helps to reduce flow separation as a direction of airflow is changed. The inventors of the present application have also determined that the rib may reduce noise generated by the attachment in use by reducing flow separation.

The attachment may be configured such that airflow exiting the air outlet generates a first force to attract hair toward the curved surface, and a second force to push hair away from the curved surface. This may achieve a smooth finish by attracting long hairs toward the curved surface whilst pushing short hairs away from the curved surface, through the long hairs, in the manner described above. The attachment may be configured such that a negative pressure region is generated in the vicinity of the curved surface in use.

The rib may be positioned to align airflow before the airflow flows across the curved surface. This may provide a more laminar airflow across the curved surface which may, in turn, provide a smoother finish in the manner described above.

The rib may be positioned to bisect airflow exiting the air outlet to align airflow. That is, airflow may flow across either side of the rib. The rib may centrally bisect airflow, or may asymmetrically bisect airflow exiting the air outlet. The inventors of the present application have established that bisecting airflow exiting the air outlet can provide a more laminar airflow across the curved surface, which may provide better smoothing performance. The rib may be movable relative to the air outlet. This may cause airflow exiting the air outlet to have different characteristics when the rib is in different positions relative to the air outlet, which may be useful for different styling effects and/or for styling different hair types.

The air outlet may be elongate, for example a rectangular slot, which may provide a more laminar airflow exiting the air outlet. The rib may be elongate, having a length at least as long as a length of the air outlet. This may help to increase the effect of airflow alignment by the rib due to the rib interacting with airflow along substantially the entire length of the air outlet.

The curved surface may comprise a Coanda surface, for example a convex surface along which airflow is attached as a result of the Coanda effect in use.

The curved surface may be substantially smooth and uninterrupted in form. This may enable hair to wrap around the curved surface in use.

The curved surface may comprise a radius of curvature in the region of 10mm to 60mm. The applicant has found that such a radius of curvature may be particularly effective in generating an airflow along the curved surface that results in a first force to attract hair toward the curved surface, and a second force to push hair away from the curved surface. The curved surface may comprise a substantially constant radius of curvature.

The attachment may comprise connecting members for holding the rib in position in airflow exiting the air outlet. The connecting members may help to locate the rib in a desired position relative to airflow exiting the air outlet, for example in such a position that the rib bisects airflow exiting the air outlet.

The connecting members may be rigidly connected to the rib such that the rib cannot move relative to the connecting members. The connecting members may prevent the rib from moving in the airflow, for example fluttering in the airflow, which may improve alignment of airflow by the rib compared to a movable connection between the rib and the connecting members.

Airflow may pass between adjacent connecting members to allow the rib to interact with airflow when the rib is connected to connecting members. This may allow the rib to bisect airflow exiting the air outlet.

The connecting members may be equally spaced along a length of the rib. This may help to reduce stress in the rib during operation of the attachment, and therefore may reduce the risk of failure of the rib.

The rib and the connecting members may form a single body, for example a single monolithic component. This may provide a simpler arrangement than, for example, a corresponding arrangement where the rib and connecting members are multiple bodies, which may reduce component count and cost, and may reduce a risk of failure in use.

The rib may have smooth edges to reduce turbulence in the airflow and thus reduce flow separation and provide a more laminar flow.

The attachment may comprise a channel for turning airflow exiting the air outlet turned towards the curved surface. The channel may allow airflow to exit the air outlet in a number of directions whilst ensuring that the airflow is turned to flow across the curved surface in a desired direction. The rib may be positioned to smooth airflow in the channel to provide a more laminar airflow across the curved surface.

The channel may comprise an arced surface for channelling airflow across the curved surface. This may help to reduce separation of the airflow to maintain a more laminar airflow.

The channel may define a channel outlet. The channel outlet may have a smaller open cross-sectional area than the air outlet. This may cause air velocity to increase as airflow passes through the channel from the air outlet to the channel outlet, which may be advantageous for styling hair as air flows across the curved surface. Channelling airflow from a larger open cross-sectional area at the air outlet to a smaller open cross-sectional area at the channel outlet may generate a converging airflow at the channel outlet, which may reduce noise and improve hair alignment performance.

The attachment may comprise a first channel for directing airflow in a first direction across the curved surface and a second channel for directing airflow in a second, opposite direction across the curved surface. The first and second channels may be arranged as described above. The first and second channels may allow a user to use the attachment in different orientations to style hair.

The rib may be movable relative to the air outlet to smooth airflow in the first and second channels. This may allow the rib to align airflow across the curved surface in the first or second direction dependent on a position of the rib relative to the first and second channels.

The first channel may be arranged to direct airflow across a first region of the curved surface and the second channel may arranged to direct airflow across a second, different region of the curved surface, the first and second regions of the curved surface being adjacent to and downstream of opposite sides of the air outlet. This may allow air to flow in opposite directions relative to the air outlet to allow a user to use the attachment in different orientations to style hair on both sides of the head.

The first and second channels may comprise arced surfaces for channelling airflow across the curved surface. This may help to reduce separation of the airflow to maintain a more laminar airflow.

The attachment may comprise a switching member for switching airflow between the first and second channels, the switching member movable from a first switch position in which airflow passes through the first channel across the first region of the curved surface in a first direction and does not pass through the second channel, to a second switch position in which airflow passes through the second air outlet across the curved surface in a second, opposite direction and does not pass through the first channel. The attachment may thus be advantageous as the attachment can be used in two different modes depending on the position of the switching member and thus the direction of airflow across the curved surface. For example, the switching member may be placed in the first switch position to style hair on a first side of the head and in the second switch position to style hair on a second side of the hair.

The rib may be connected to the switching member such that a position of the rib relative to the first and second channels is different dependent on whether the switching member is in the first switch position or the second switch position. This may help to ensure that the rib is correctly positioned to align airflow in the first and second channels. This may help the rib to provide optimised airflow alignment dependent on the position of the switching member to that airflow can be smoothed by the rib regardless of which direction around the curved surface it is directed. For example, the rib may be connected to the switching members by the connecting members.

The rib may be positioned relative to the switching member such that air flows between the rib and the switching member. This may allow the rib to bisect airflow as described above.

The rib may be rigidly connected to the switching member to ensure a correct position of the rib in the airflow and thus that the rib interacts with the airflow in a repeatable and reliable way when the switching member is in the first and second switch positions. This may also aid in manufacturing simplicity and in ensuring.

The switching mechanism may form a seal between the first and second channels when the switching member is in the first switch position and the second switch position. This may reduce air loss as air flows through the respective first or second channel, thus increasing the air flow rate across the curved surface and thereby increasing the performance of the attachment.

The switching member may be elongate, having a length at least as long as a length of the air outlet. This may reduce air loss as air flows through the respective first or second outlet, thus increasing the air flow rate across the curved surface and thereby increasing the performance of the attachment.

The switching member may comprise an arced surface for turning airflow toward the first or second channel. That is, the switching member may be concave to help align airflow as it turns toward the curved surface. The arced surface may help maintain a more laminar air flow.

The first and second channels may be substantially equal in size and shape. This may help to ensure that air velocity across the curved surface is equal when the switching member is in the first switch position or the second switch position, for the same airflow generated by the airflow generator. This may also help to ensure even styling on both sides of the head.

The attachment may comprise a retention mechanism for retaining the switching member in one of the first and second switch positions in the absence of an applied force to the switching member by a user of the attachment. This may be advantageous as the switching member is retained in the first or second position by the retention mechanism in the absence of an applied force to the switching member by a user of the attachment, allowing the user to change an orientation of the attachment without the switching member moving between the first and second positions. This may enable the user to style curls into the hair by, for example, rotating the attachment.

The retention mechanism may help a user to use the attachment in a variety of orientations without the switching member moving between the first and second switch positions. The retention mechanism may be arranged to retain the switching member in the other of the first and second switch positions upon application of an applied force to the switching member by a user of the attachment. This provides assurance to the user that the switching member is positioned correctly. This also ensures a correct direction of airflow across the curved surface to provide better styling performance.

The retention mechanism may comprise a releasable mechanical fastener for retaining the switching member in the first and second switch positions. For example, the releasable mechanical fastener may comprise a hook, detent or press stud. This may provide a simple way of retaining the switching member in position until application of a force by a user, which may reduce manufacture and assembly complexity.

The retention mechanism may comprise a biasing element for biasing the switching member to the first and second switch positions. For example, the retention mechanism may comprise a bi-stable spring that is stable in the first and second switch positions. The biasing element may help to ensure the switching member properly reaches the first and second switch positions to ensure proper switching of airflow between the first and second channels. The biasing element may also increase the force required to move the switching member between the first and second switch positions which may help to prevent inadvertent movement of the switching member.

The retention mechanism may comprise a first pair of magnetic elements configured to retain the switching member in the first switch position and a second pair of magnetic elements configured to retain the switching member in the second switch position. Each magnetic element in a pair of magnetic elements is magnetically attracted to the other magnetic element of the pair. This may provide a simple mechanism for retaining the switching member in the desired switch position and for a user to apply a force against the pair of magnetic elements to move the switching member of the other switch position. For example, a first magnetic element of each of the first and second pairs of magnetic elements may be located in the switching mechanism and a second magnetic element of each of the first and second pairs of magnetic elements may be located in an adjacent location within the attachment, the first magnetic elements being attracted to the second magnetic elements.

A minimum applied force required to overcome the retention mechanism to move the switching member between the first switch position and the second switch position may be in the region up to 5N. A minimum applied force required to overcome the retention mechanism to move the switching member between the first switch position and the second switch position may be in the region of 0.3N to 3N. The inventors of the present application have found that such forces are suitable for a user to apply to the switching member with an intent to move the switching member and to prevent inadvertence movement of the switching member during normal use of the attachment.

The attachment may comprise a main body defining the air outlet and the curved surface. The main body may be rotatable relative to the rib between a first position in which airflow exiting the air outlet interacts with the rib and a second position, in which airflow exiting the air outlet does not interact with the rib. This may allow the attachment to operate in different modes dependent on the position of the main body. For example, the attachment may be used for hair styling when the main body is in the first position and hair drying when the main body is in the second position.

The first and second positions may be 180 degrees apart from one another. This may aid weight distribution within the attachment as the main body is rotated between the first and second positions, increasing the ease of handling by a user. This may also enable a user to easily ascertain a mode that the attachment is operating.

The attachment may comprise a spring plunger connected to the main body for locating the main body in the first and second positions. This may provide feedback to a user to confirm that the main body is in the first or second position. The attachment may further comprise a pair of ramps arranged to engage with the spring plunger for limiting a range of movement of the spring plunger. The main body may be generally cylindrical. This may help to aid a smooth rotation of the main body between the first and second positions. The main body may be configured to direct airflow exiting the air outlet in a radial direction. That is, the main body is configured such that airflow exits the air outlet in a direction normal to the outer surface of the main body in which the air outlet is defined. This may aid in ease of use of the attachment when drying hair with the main body in the second position.

The rib may be arranged relative to airflow exiting the air outlet to align airflow turning from the radial direction toward the curved surface when the main body is in the first position. The rib may thus provide a more laminar airflow by smoothing airflow as it turns toward the curved surface.

The curved surface may comprise an outer surface of the main body. This may allow for a simpler attachment compared to one where the main body and the curved surface are separate. The curved surface may comprise a single curved surface extending around substantially all of the main body from the first side of the air outlet to the second side of the air outlet. This may allow for smoother rotation of the main body relative to the rib.

The first and second channels may be for directing airflow in opposite directions around the curved surface of the main body when the main body is in the first position. This may allow a user to style hair on different sides of the head.

The curved surface may comprise first and second regions on opposite sides of the air outlet. When the main body is in the first position, the first channel is for directing airflow from the air outlet across the first region in a first direction and the second air outlet is for directing airflow from the air outlet across the second region in a second, opposite direction. The first and second regions may extend away from the respective sides of the air outlet to such an extent that they adjoin on an opposite side of the main body to the air outlet to provide a continuous surface extending from a first side of the air outlet to a second side of the air outlet. This provides the benefit of the main body requiring a single air outlet whilst the attachment affords the ability to direct air in opposite directions across the curved surface to style hair on different sides of the head.

The attachment may comprise a user interface operable by a user to move the rib relative to the air outlet. The user interface may, for example, comprise one or more of a handle, high friction gripping surface, knob, push button, toggle or touch screen. This may aid in simplifying a process for a user to move the rib. For example, the rib may be connected to the switching member and the user interface may comprise a handle positioned on the switching member and movable by a user to move the switching member between the first switch position and the second switch position and thus move the rib relative to the air outlet.

The attachment may comprise a guide. The guide may comprise one or more of the rib, the channel(s), the switching member and the retaining mechanism. This may allow movement of the rib, the channel(s), the switching member and the retaining mechanism relative to the air outlet to allow the attachment to operate in different modes.

The guide may be configured such that the second channel is blocked by the switching member when the switching member is in the first switch position and the first channel is blocked by the switching member when the switching member is in the second switch position. This may help to ensure that airflow can flow across only the first or second region of the curved surface, depending on the position of the switching member, to provide a greater airflow over the curved surface in the desired direction.

The attachment may comprise a flat surface adjacent to and extending rearwardly from the channel outlet. The flat surface may be comprised in the guide.

Where a non-flat surface, is provided extending rearwardly from the channel outlet, the smooth finish can be disturbed as the attachment is moved relative to the hair in use, as may typically be the case during styling operations. Where a rough surface, for example a surface comprising projections such as bristles or the like, is provided extending rearwardly from the channel outlet, such a rough surface may interrupt hair that has already been smoothed by airflow from the channel outlet as the attachment is moved relative to the hair in use. By providing a curved surface adjacent to and downstream of the channel outlet, and a flat surface adjacent to and extending rearwardly from the channel outlet, a smooth hair finish may be created and maintained as the attachment is moved relative to hair by a user in use.

The flat surface may also act as a guide surface to ensure that the attachment is located correctly relative to a head of a user such that airflow exiting the channel outlet is able to provide the functionality described above.

The flat surface may be substantially smooth and uninterrupted in form. The flat surface may comprise a height in the region of 5mm to 20mm.

The attachment may be configured such that the flat surface contacts hair extending rearwardly from the channel outlet as the attachment is moved relative to hair in use, for example as the attachment is moved linearly in a direction along the hair, from roots of the hair to tips of the hair in use.

The flat surface may comprise a generally planar surface. This may aid with retention of a smooth hair surface as the attachment is moved relative to hair in use, and may ensure that hair extending rearwardly from the channel outlet is supported by the surface.

The flat surface may be obliquely angled relative to a plane of the channel outlet. This may ensure that hair extending rearwardly from the channel outlet contacts the flat surface whilst hair downstream of the channel outlet is attracted toward the curved surface in use. The flat surface may be obliquely angled relative to a plane tangential to the curved surface at a point of the curved surface immediately adjacent to the channel outlet.

The attachment may comprise a pair of guide walls for guiding airflow along the curved surface, the pair of guide walls upstanding from the curved surface. By providing a pair of guide walls extending outwardly from the curved surface ambient air may be inhibited from impacting on a region of negative pressure generated by airflow flowing along the curved surface in use, and may result in increased attraction of hair toward the curved surface compared to, for example, a similar arrangement that does not utilise guide walls.

Each of the guide walls may be curved in form, for example with a curvature following a curvature of the curved surface. Guide walls of the pair of guide walls may oppose one another, for example such that a channel is defined therebetween, with the curved surface forming a bed of the channel. The pair of guide walls may be spaced apart along the curved surface from one another, for example spaced apart at opposing edges of the curved surface. A spacing between the guide walls may correspond substantially to a length of the air outlet. The curved surface may be substantially smooth and uninterrupted between the pair of guide walls. This may enable hair to wrap around the curved surface between the pair of guide walls in use.

The guide walls may project outwardly from the curved surface, for example with the guide walls and the curved surface integrally formed as a single component. The pair of guide walls may comprise a height substantially equal to a height of the channel outlet. This may ensure that a negative pressure region is maintained along substantially the entire height of a jet of air that exits the channel in use.

The pair of guide walls may comprise a height substantially equal to a height of the channel outlet in a region adjacent to the channel outlet. The inventors of the present application have found that maintaining a negative pressure region in the region adjacent to the channel outlet benefits creation of airflow along the curved surface which results in a first force that is sufficient to attract relatively long hair toward the first surface whilst also generating a second force to push relatively short hair away from the curved surface.

The pair of guide walls may comprise a radius of curvature greater than a radius of curvature of the curved surface. For example, the pair of guide walls may comprise a radius of curvature greater than a radius of curvature of the curved surface in a region adjacent to the channel outlet. This may ensure that the pair of guide walls provide their functionality in the region adjacent to the respective first or second air outlet in use.

The pair of guide walls may comprise a height that varies along a length of the guide wall. The inventors of the present application have found that the guide walls provide most impact in certain regions of the curved surface, for example in a region adjacent to an air outlet. The pair of guide walls may comprise a height that decreases in a direction away from the channel outlet. By reducing a height of the guide walls in a direction away from the channel outlet less material may be required to form the guide walls than, for example, guide walls of a constant height. The pair of guide walls may comprise a height that gradually decreases in a direction away from the channel outlet, for example such that there are no step-changes in height. Guide walls of the pair of guide walls may each comprise the same height, and may be substantially symmetrical about an axis bisecting a space between the guide walls.

The pair of guide walls may comprise a constant height. This may provide certainty that a negative pressure region generated adjacent to the curved surface will not be impacted along the length of the curved surface.

The guide walls may extend around the main body from the first channel to the second channel. The main body may be configured to rotate within the pair of guide walls. This may help to stabilise the main body relative to the guide to ensure smooth motion of the main body between the first and second positions.

The channel outlet may be a fixed air outlet, for example an air outlet of fixed cross- sectional area, length and/or width. This may ensure that airflow characteristics of the attachment are constant for a given flow rate of airflow generated by the airflow generator, thereby ensuring that an airflow is generated along the curved surface that results in a first force to attract hair toward the curved surface, and a second force to push hair away from the curved surface. This may ensure a constant airflow along a length of the air outlet, allowing more aligned hair smoothing by the attachment. This may also provide a simpler attachment with fewer moving parts, and hence a reduced risk of failure, compared to a attachment with a variable air outlet.

The curved surface may comprise a continuous surface extending between the first and second channels. Such a continuous surface may facilitate attraction of hair to the curved surface when the attachment is used in multiple orientations.

The main body may comprise an internal baffle for turning airflow from the airflow generator toward the air outlet, for example turning airflow through around 90 degrees toward the air outlet. This may enable a main portion of the attachment housing the airflow generator to extend orthogonally relative to the air outlet, which may provide greater flexibility in design, and better ergonomics, than, for example a attachment where the air outlet is aligned with a main portion of the attachment housing the airflow generator.

The attachment may comprise a heater for heating the airflow. This may provide increased styling flexibility, and may, for example, enable the airflow to provide a drying function.

The attachment may comprise a handle unit within which the airflow generator is housed, and an attachment releasably attachable to the handle unit, the attachment comprising the air outlet, the curved surface, and the rib. Providing described removable attachment may allow the functionality described herein to be selectively provided by a user.

According to a second aspect of the present invention there is provided a haircare appliance comprising an air inlet, an air outlet, an airflow generator for generating an airflow from the air inlet to the air outlet, a curved surface adjacent to and downstream of the air outlet, and a rib positioned such that the rib interacts with airflow exiting the air outlet to align the airflow exiting the air outlet. The haircare appliance may comprise a heater for heating the airflow. This may provide increased styling flexibility, and may, for example, enable the airflow to provide a drying function. The heater may be configured to operate at a particular temperature dependent on whether the main body is in the first position or the second position.

The haircare appliance may comprise a handle unit within which the airflow generator is housed, and an attachment according to the first aspect of the present invention, the attachment releasably attachable to the handle unit. Providing a removable attachment may allow the functionality of the attachment described herein to be selectively provided by a user.

Optional features of aspects of the present invention may be equally applied to other aspects of the present invention, where appropriate.

Figure 1 is a schematic view illustrating a haircare appliance according to the present invention;

Figure 2 is a schematic cross-sectional view through a handle unit of the haircare appliance of Figure 1;

Figure 3 is a schematic perspective view of an embodiment of an attachment for the haircare appliance of Figure 1, illustrating the attachment in a second mode;

Figure 4 is a schematic cross-sectional view of the attachment of Figure 3, illustrating the attachment in the second mode;

Figure 5 is a schematic perspective view of the attachment of Figure 3, illustrating the attachment in a first mode; Figure 6 is a schematic view illustrating forces created by airflow through the attachment of Figure 3 in use in the first mode;

Figure 7 is a schematic top view of the attachment of Figure 3, illustrating the attachment in the first mode and a first switch position;

Figure 8 is a schematic top view of the attachment of Figure 3, illustrating the attachment in the first mode and a second switch position; and

Figure 9 is a schematic exploded view of the attachment of Figure 3.

A haircare appliance according to the present invention, generally designated 10, is shown schematically in Figure 1.

The haircare appliance 10 comprises a handle unit 12, and an attachment 100 removably attachable to the handle unit 12.

The handle unit 12 comprises a housing 14, an airflow generator 16, a heater 18, and a control unit 20, as can be seen schematically in Figure 2.

The housing 14 is tubular in shape, and comprises an air inlet 22 through which an airflow is drawn into the housing 14 by the airflow generator 16, and an air outlet 24 through which the airflow is discharged from the housing 14. The airflow generator 16 is housed within the housing 14, and comprises an impeller 26 driven by an electric motor 28. The airflow generator is configured to generate airflow at a flow rate in the region of 8 to 18 L/S, for example in the region of 10 to 16L/s. An appropriate airflow generator is the Dyson V9 Digital Motor, produced by Dyson Technology Limited. The heater 18 is also housed within the housing 14, and comprises heating elements 30 to optionally heat the airflow. The control unit 20 comprises electronic circuitry for a user interface 32 and a control module 34. The user interface 32 is provided on an outer surface of the housing 14, and is used to power on and off the haircare appliance 10, to select a flow rate (for example high, medium and low), and to select an airflow temperature (for example hot, medium or cold). In the example of Figure 1, the user interface comprises a plurality of sliding switches, but other forms of user interface 32, for example buttons, dials or touchscreens, are also envisaged.

The control module 34 is responsible for controlling the airflow generator 16, and the heater 18 in response to inputs from the user interface 32. For example, in response to inputs from the user interface 32, the control module 34 may control the power or the speed of the airflow generator 16 in order to adjust the airflow rate of the airflow, and the power of the heater 18 in order to adjust the temperature of the airflow.

The attachment 100 is shown schematically in Figures 3-5 and 7-9.

The attachment 100 comprises a main body 102 comprising an air inlet 108, an air outlet 110, a curved surface 104, and a plurality of internal baffles 114. The attachment comprises a guide 120, which when aligned with the air outlet 110 of the main body 108 directs airflow from the air outlet 110 across the curved surface 104 of the main body, such that airflow directed by the guide 120 generates a first force to attract hair toward the curved surface 104, and a second force to push hair away from the curved surface 104.

The air inlet 108 comprises a generally circular aperture formed in the main body 102, and the air inlet 108 is configured to receive airflow from the air outlet 24 of the handle unit 12 when the attachment 100 is attached to the handle unit 12 in use. A periphery of the air inlet 108 comprises attaching features for releasably attaching the attachment 100 to the handle unit 12. The attaching features may take many forms, are not pertinent to the present invention, and so will not be described for the sake of brevity. The air outlet 110 comprises a generally rectangular slot formed lengthwise along the curved surface 104 of the main body 102. The air outlet 110 comprises a series of baffles extending across a width of the air outlet 110. The baffles may help to align airflow exiting the air outlet 110 and may help prevent hair from inadvertently entering the air outlet 110.

A cross-sectional view of the curved surface 104 is illustrated schematically in Figure 4. The main body 102 is generally cylindrical and the curved surface 104 is the circumferential surface of the main body 102. Thus, the curved surface 104 is located adjacent to, and downstream of, the air outlet 110. It will be appreciated that in other embodiments, the main body 102 may not be generally cylindrical and the curved surface 104 may extend only partially around the main body 102.

The main body 102 is configured to direct airflow exiting the air outlet 110 in a radial direction. The guide 120 is arranged to turn airflow exiting the air outlet 110 from the radial direction towards a tangential direction of a region of the curved surface 104 adjacent to and downstream of the air outlet 110.

The curved surface 104 is substantially smooth and uninterrupted in form, such that no projections, recesses or apertures are formed thereon. This may enhance the functionality of the attachment 100 which will be described hereafter. The curved surface 104 has a radius of curvature in the region of 10mm to 60mm, for example in the region of 15mm to 40mm. In a presently preferred embodiment, the curved surface 104 has a radius of curvature in the region of 20mm. The inventors of the present application have found that such a geometry of the curved surface 104 may provide advantageous effects, as will be described hereafter.

The plurality of internal baffles 114 are curved in form and extend in a direction from the air inlet 108 to the air outlet 110. The plurality of internal baffles 114 are configured to turn airflow in a direction from the air inlet 108 to a direction toward the air outlet 110, such that airflow is turned through substantially 90 degrees from the air inlet 108 to the air outlet 110. This may enable the handle unit 12 to extend orthogonally relative to the air outlet 110, which may provide greater flexibility in design, and better ergonomics, than, for example a haircare appliance where the air outlet is aligned with a handle unit of the haircare appliance.

The main body 102 is rotatable about its central longitudinal axis 103 relative to the guide 120, between a first position in which airflow exiting the air outlet 110 is directed by the guide 120, as shown in Figures 5, 7 and 8, and a second position in which airflow exiting the air outlet 110 is not directed by the guide 120, as shown in Figures 3 and 4. The direction of airflow out of the air outlet 110 is denoted by arrow 101 in Figures 4, 7 and 8, which show different operating configurations of the attachment 100.

The position of the main body 102 relative to the guide 120 determines an operating mode of the haircare appliance 100. In this embodiment, when the main body 102 is in the first position, as shown in Figures 5, 7 and 8, the haircare appliance 100 is configured to operate in a first, styling mode and airflow is guided by the guide 120 across the curved surface 104. When the main body 102 is in the second position, as shown in Figures 3 and 4, the haircare appliance 100 is configured to operate in a second, drying mode and airflow exits the air outlet 110 towards a user’s hair.

The first and second positions of the main body 102 are 180 degrees apart from one another. That is, the main body 102 is rotated by 180 degrees relative to the guide 120 to move between the first and second positions. In other embodiments the first and second positions may be less than 180 degrees apart from one another.

The attachment 100 comprises a handle 112 protruding from a distal end of the main body 102. The distal end is an opposite end of the main body 102 to the air inlet 108. The handle 112 is rigidly attached to the main body and is rotatable by a user to rotate the main body 102 relative to the guide 120 between the first and second positions. It will be appreciated that the handle 112 could be provided in any suitable form for operation by a user to rotate the main body 102 relative to the guide 120, for example a toggle, push button or touch screen. The handle 112 is comprised in a cool tip which is relatively insulated from the heat of the airflow within the attachment.

The guide 120 is arranged to turn airflow exiting the air outlet 110 towards the curved surface 104 when the main body 102 is in the first position, as shown in Figures 5, 7 and 8. The inventors of the present application have found that airflow attaches to the curved surface 102 via the Coanda effect. With reference to the schematic illustration of the interaction of forces shown in Figure 6, when a tress of hair is brought into the vicinity of the attachment 100, long hairs of the tress are attracted to, and at least partially wrapped about, the curved surface 102 by a force F PULL, as a result of a negative pressure region generated by the airflow over the curved surface 102. However, the pressure gradient across the tress also results in a force, F PUSH, which causes some airflow to pass directly through the tress. Due to the location of this force relative to the curved surface 102 and the rest of the tress, shorter hairs are only held loosely at this point compared to longer hairs which are held in place on the curved surface 102. The shorter hairs are blown through the tress toward a user’s head, whilst the longer hairs remain in place on the outside of the tress, ie the portion of the tress facing away from the user’s head. This provides a smooth finish for hair following interaction with the haircare appliance 10.

This effect can be optimised by appropriate modification of the geometries and parameters described herein. One such parameter that may provide increased effectiveness is the velocity of airflow at the air outlet 110 of the attachment 100. In particular, too great a velocity may result in shorter hairs sticking to the curved surface 102 and hence not being pushed away through longer hairs, whilst too low a velocity may not be sufficient to attract longer hairs to the curved surface 102 in the first instance.

The guide 120 comprises a first channel 122 defining a first air outlet 126, a second channel 124 defining a second air outlet 128, first and second flat surfaces 130, an inner casing 132 defining an aperture 133, a pair of guide walls 134, a switching member 140 and a retention mechanism 150, as will be described in more detail herein after. It will be appreciated that in other embodiments some of these features may be omitted.

The inner casing 132 is arranged to contact the curved surface 104 at least when the main body 102 is in the first position. The inner casing 132 defines an aperture 133 corresponding to the air outlet 110 to allow airflow to flow from the air outlet 110 to the first and second channels 122, 124. The inner casing 132 comprises raised ridges on opposite sides of the aperture 133, the ridges defining convex curved surfaces for guiding airflow from the radial direction towards the curved surface 104 of the main body 102 to provide a smoother flow path for the airflow and thus help reduce turbulence in the airflow.

The first channel 122 is arranged to direct airflow in a first direction across the curved surface 104. With respect to Figure 7, this is in an anti-clockwise direction, as denoted by the arrows 101. The second channel 124 is arranged to direct airflow in a second direction across the curved surface 104. With respect to Figure 8, this is in a clockwise direction, as denoted by the arrow 101.

The curved surface 104 comprises a continuous surface extending between the first and second air outlets 126, 128, when the main body 102 is in the first position.

The first and second air outlets 126, 128 comprise rectangular slots extending substantially parallel to the longitudinal axis 103 of the main body. The first and second air outlet 126, 128 are substantially equal in size and shape. The first and second air outlets 126, 128 have the same open cross-sectional area, which is smaller than an open cross-sectional area of the air outlet 110. This provides an increase the velocity of airflow at the first and second air outlets 126, 128 compared with the velocity of airflow at the air outlet 110 for the same air flow rate, and a converging airflow at the first and second air outlets 126, 128. The air outlet 110 and the first and second air outlets 126, 128 are fixed air outlets, each with a fixed cross-sectional area, length and width.

The first and second air outlets 126, 128 each have a length in the region of 50mm to 150mm, for example in the region of 75mm to 85mm, and a height in the region of 2mm to 5mm, for example in the region of 3.0mm to 4.5mm. This gives an overall open cross- sectional area of each of the first and second air outlets 126, 128 in the region of 140mm ² to 450mm ² , for example in the region of 225.0mm ² to 382.5mm ² .

In a presently preferred embodiment, the width of the first and second air outlets 126, 128 is in the region of 77mm, and the height of the first and second air outlets 126, 128 is in the region of 4.5mm. The open cross-sectional area of the first and second air outlets 126, 128 is in the region of 346.5mm ² . The inventors of the present application have found that such dimensions for the first and second air outlets 126, 128 may provide advantageous effects, as will be described hereafter.

The applicant has determined that a velocity in the region of 30m/s to 65m/s at the first or second air outlet 126, 128 may be particularly effective in generating an airflow along the curved surface 102 that results in a first force that is sufficient to attract relatively long hair toward the curved surface 102 whilst also generating a second force to push relatively short hair away from the curved surface 102. In a presently preferred embodiment, the velocity of airflow at the first or second air outlet 126, 128 is in the region of 55m/s.

Another parameter that may provide increased efficacy for smoothing hair in the manner described above is a ratio of the velocity of airflow at the first or second air outlet 126, 128 to a flow rate of airflow generated by the airflow generator 16. In the embodiment of Figures 5, 7 and 8, the ratio is in the region of 2.14 to 5.63, and in a particularly preferred embodiment the ratio is in the region of 2.89. The applicant has found that such a ratio may be particularly effective in generating an airflow along the curved surface 102 that results in a first force that is sufficient to attract relatively long hair toward the curved surface 102, whilst also generating a second force to push relatively short hair away from the curved surface 102.

Another parameter that may provide increased efficacy for smoothing hair in the manner described above is a ratio of flow rate of airflow generated by the airflow generator 16 to an open cross-sectional area of the first or second air outlet 126, 128. In the embodiment of Figures 5, 7 and 8, the ratio is in the region of 0.01 to 0.10, and in a particularly preferred embodiment the ratio is in the region of 0.04. The applicant has found that such a ratio may be particularly effective in generating an airflow along the curved surface 102 that results in a first force that is sufficient to attract relatively long hair toward the curved surface 102, whilst also generating a second force to push relatively short hair away from the curved surface 102.

A further parameter that may provide increased efficacy for smoothing hair in the manner described above is a ratio of a radius of curvature of the curved surface 102 to the velocity of airflow at the first or second air outlet 126, 128. In the embodiment of Figures 5, 7 and 8, the ratio is in the region of 0.33 to 2.00, and in a particularly preferred embodiment the ratio is in the region of 0.57. The applicant has found that such a ratio may be particularly effective in generating an airflow along the curved surface 102 that results in a first force that is sufficient to attract relatively long hair toward the curved surface 102, whilst also generating a second force to push relatively short hair away from the curved surface 102.

The flat surfaces 130 are located adjacent to and extending rearwardly from of the first and second air outlets 126, 128, such that the flat surfaces 130 extend rearwardly from an edge of the first and second air outlets 126, 128. The flat surfaces 130 are obliquely angled relative to a respective plane in which the first and second air outlets 126, 128 are disposed, for example at an angle in the range of 3-10 degrees. The flat surfaces 130 are generally planar in form, and are substantially smooth and uninterrupted, for example with no projections, recesses or apertures formed thereon. The flat surfaces 130 have a height in the region of 5mm to 20mm. The functionality of the flat surfaces 130 will be described hereafter. It will be appreciated that in embodiments in which the guide 120 comprises only one channel defining a channel outlet 126, 128, the guide comprises a single flat surface 130 adjacent to and extending rearwardly from the channel outlet 126, 128.

The pair of guide walls 134 are for directing airflow along the curved surface 104 and are disposed on opposing edges of the curved surface 104. The guide walls 134 are upstanding from the curved surface 104. The guide walls 134 extend along the full arc length of the curved surface 104. In this embodiment the guide walls 134 extend around the main body 102 to form a pair of rings within which the main body 102 rotates. That is, the guide walls 134 extend from around the main body 102 from the first air outlet 126 to the second air outlet 128. The guide walls 134 have a height substantially corresponding to a height of the first and second air outlets 126, 128, and have a constant height along their length.

As mentioned above, the pair of guide walls 134 extend along opposing edges of the curved surface 104. This effectively creates an airflow channel, with the pair of guide walls 134 acting as walls of the channel, and the curved surface 104 acting as a bed of the channel. The guide walls 134 inhibit ambient air from interacting with airflow flowing along the curved surface 104 in use, which may maintain the negative pressure region created by airflow flowing along the curved surface 104.

The attachment 100 comprises a switching member 140 for switching airflow between the first and second air outlets 126, 128. The switching member 140 is movable from a first switch position (as shown in Figure 7) to a second switch position (as shown in Figure 8). In the first switch position, and when the main body 102 is in the first position, airflow passes through the first air outlet 126 across the curved surface 104 and does not pass through the second air outlet 128. In the second switch position, and when the main body 102 is in the first position, airflow passes through the second air outlet 128 across the curved surface 104 and does not pass through the first air outlet 126. The switching member 140 is arranged to form a seal between the first air outlet 126 and the second air outlet 128 when the switching member 140 is in the first switch position and the second switch position, to block the first or second channel 122, 124. In this embodiment, an edge of the switching member 140 is arranged to contact the inner casing 132 of the guide 130 to block airflow to the respective first or second channel 122, 124 and allow airflow to pass through the other of the first or second channel 122, 124.

The switching member 140 is elongate, having a length at least as long as a length of the air outlet 110. The switching member 140 is at least as long as a length of the first and second air outlets 126, 128. The switching member 140 extends substantially parallel to a longitudinal axis 103 of the main body 102.

The switching member 140 comprises an arced, or curved surface 146 for turning airflow toward the first or second air outlet 126, 128. The switching member 140 thus forms a concave surface for guiding airflow from a radial direction of the main body 102 towards a tangential direction of the curved surface 104.

The attachment 100 comprises a handle 142 positioned on the switching member 140. The handle 142 is movable by a user to move the switching member 140 between the first switch position and the second switch position. The switching member 140 and the handle 142 form a single body. It will be appreciated that any other suitable user interface could be employed to move the switching member 140 between the first and second switch positions.

The switching member 140 is movable between the first and second switch positions about a pivot 144 such that the switching member 140 rotates about the pivot 144. The switching member 140 rotates about the pivot 144 by an angle in the regions of 18 degrees to 30 degrees to move between the first and second switch positions, for example between 22 and 26 degrees. The handle 142 is positioned on an outer portion of the switching member 142, the outer portion being further from the longitudinal axis 103 of the main body 102 than the pivot 144. The handle is therefore more easily accessible to the user. It will be appreciated that in other embodiments, the switching member 140 may move between the first and second switch positions in any suitable way, such as sliding of the switching member 140 relative to the air outlet 110.

The attachment 100 comprises a retention mechanism 150. The retention mechanism is for retaining the switching member 140 in one of the first and second switch positions in the absence of an applied force to the handle 142 of the switching member 140 by a user of the haircare appliance 10. The retention mechanism 150 is arranged to retain the switching member 140 in the other switch position upon application of an applied force to the handle 142 of the switching member 140 by a user of the haircare appliance 10. With reference to Figures 7 and 8, the retention mechanism 150 holds the switching member 140 in the first switch position shown in Figure 7 until a user applies a force (denoted by arrow 152) to the handle 142. Upon application of the force 152, the switching member 140 is released from the first switch position and moved to the second switch position shown in Figure 8, where it is held by the retention mechanism 150 until application of force to the handle 142 by a user.

The retention mechanism 150 comprises a first pair of magnetic elements 154 configured to retain the switching member 140 in the first switch position and a second pair of magnetic elements 156 configured to retain the switching member 140 in the second switch position. A first magnetic element in each of the pairs of magnetic elements 154, 156 is located on an inner side of the respective flat surface 130 and a second magnetic element in each of the pairs of magnetic elements 154, 156 is located at an opposing location on the switching member 140 to the first magnetic element in the respective pair of magnetic elements 154, 156. In this example, the first magnetic element in each of the pairs of magnetic elements 154, 156 comprises a sheet metal and the second magnetic element in each of the pairs of magnetic elements 154, 156 comprises a magnet arranged to attract the sheet metal. It will be appreciated that the retention mechanism may comprise other forms of retention, such as releasable mechanical fasteners and a biasing element. The second magnetic element in each of the pairs of magnetic elements 154, 156 is positioned on an inner portion of the switching mechanism 140, the inner portion being closer to the longitudinal axis 103 of the main body 102 than the pivot. This may prevent a user from being able to access the magnetic elements and thus tamper with them.

A minimum force 152 required to overcome the retention mechanism 150 to move the switching member 140 between the first switch position and the second switch position is in the region up to 5N, more specifically 0.3N to 3N.

The attachment 100 comprises a rib 148, which, in this embodiment, is connected to the switching member 140. The rib 148 is positioned such that it interacts with airflow exiting the air outlet 110 to align the airflow exiting the air outlet 110, thus providing a more laminar flow at the respective first of second air outlets 126, 128. The rib 148 is positioned relative to the first and second channels 122, 124 to smooth airflow in the first and second channels 122, 124 and thus provide a more laminar airflow at the first and second air outlets 126, 128 before the airflow flows across the curved surface.

The rib 148 interacts with airflow exiting the air outlet 110 to provide a more aligned, smoother, more laminar flow at the first air outlet 126 which in turn provides a more cohesive airflow across the curved surface 104. As airflow is turned, the airflow typically separates and thus becomes more turbulent and noisy. The rib 148 has an upper and a lower surface along which airflow passes as it flows through the first and second channels 122, 124 which helps to reduce flow separation and thus turbulence and noise compared to an attachment 100 without the rib 148.

The rib 148 is movable relative to the air outlet 110 by virtue of being connected to the switching member 140. The rib 148 may thus be movable relative to the air outlet 110 by a user applying a force to the handle 142 to move the switching member 140, and therefore the rib, between the first and second switch positions. The rib 148 is elongate, having a length at least as long as a length of the air outlet 110 such that the rib 148 interacts with air across substantially all of the length of the air outlet 110

The rib 148 comprises substantially smooth edges to reduce turbulence in the first and second channels 122, 124.

The rib 148 is held apart from the curved surface 146 of the switching member 140 by connecting members 149 (best shown in Figure 9) to allow airflow to flow across either side of the rib 148. Airflow exiting the air outlet 110 is bisected by the rib 148 and passes between adjacent connecting members 149, when the main body 102 is in the first position.

The connecting members 149 are spaced along a length of the rib 148. The connecting members 149 rigidly connect the rib 148 to the switching member 140 such that the rib 148 is immovable relative to the switching member 140. It will be appreciated that in other embodiments, the rib 148 may be movable relative to the switching member 140.

The rib 148 and the connecting member 149 form a single body.

The haircare appliance 10 comprises an alert module 36. The alert module is arranged to provide to alert a user that the main body 102 is in the first position or the second position and/or to alert a user that the switching member 140 is in the first switch position of the second switch position. The alert module 36 comprises one or more of a haptic feedback module, an audible indicium or a visual indicium. In this embodiment the alert module 36 is shown as being in the handle unit 12, but it will be appreciated that in other embodiments the alert module 36 may be comprised in the attachment 100. The haircare appliance 10 may comprise separate alert modules 36 for the main body 102 and the switching member 140. In use, the attachment 100 is attached to the handle unit 12. The airflow generator 16 generates an airflow from the air inlet 22 of the handle unit 12 to the air outlet 24 of the handle unit 12, such that airflow passes from the air outlet 24 of the handle unit to the air inlet 108 of the attachment 100. Airflow flows from the air inlet 108 of the attachment through the main body 102, and is turned by the plurality of internal baffles 114 toward the air outlet 110 of the attachment 100. Airflow exits the main body 102 via the air outlet 110 and passes over the curved surface 102 if the main body 102 is in the first position or flows in a radial direction of the main body 102 if the main body 102 is in the second position.

In use, the main body 102 is rigidly held in position relative to the handle unit 12 and the guide 120 is rotatable relative to the handle unit 12 to move the main body 102 between the first and second positions. It will be appreciated that in other embodiments, the guide 120 may be rigidly positioned relative to the handle unit 12 and the main body 102 is rotatable relative to the handle 12 and the guide 120 between the first and second positions.

In use, the switching member 140 is moveable between the first and second switch positions upon application of a force by a user to the handle 142. The force may be applied by a user’s hand, or force generated upon contact between the handle 142 and the user’s hair and/or head. The handle 142 is located at a rear edge of the flat surfaces 130 and therefore may contact the user’s hair and/or head in use, as described in more detail hereinafter, to move the switching member between the first and second switch positions.

In use, the attachment 100 can be moved along a length of a tress of hair, for example in a direction from root to tip of hair of the tress. A respective one of the flat surfaces 130 is positioned relative to the curved surface 104 such that the flat surface 130 contacts hair extending rearwardly from of the air outlet 110 whilst hair downstream of the air outlet 110 contacts the curved surface 104. As previously mentioned, the flat surface 130 is substantially smooth and uninterrupted in form, with no projections, recesses or apertures formed thereon. As the haircare appliance 10 is moved along a length of a tress of hair in use, the flat surface 130 passes across hair that has been smoothed via interaction with the curved surface 104. In view of the smooth and uninterrupted nature of the flat surface 130, the flat surface 130 does not disrupt hair that has already been smoothed, leading to a better finish than, for example, a corresponding haircare appliance that has bristles and/or further air outlets located rearwardly of the air outlet 110.

Although described herein as embodiments with releasable attachments, embodiments are also envisaged where, rather than the haircare appliance comprising a handle unit and an attachment the haircare appliance is a single-piece unit, for example taking the form of the combined handle unit and attachment previously described.