Attachment for a haircare appliance

Abstract

An attachment (100, fig.1) for a haircare appliance (10, fig,1) comprising an air guide (150, fig.11) movable, preferably rotatable via a user interface or knob (160, fig.5), between a first position

Description

B ACKGROUND Haircare appliances are typically used to dry and style hair. Users have different preferences for the type of airflow used to dry hair, for example depending on the length or thickness of the hair to be dried. 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 A first aspect of the present invention provides an attachment for a haircare appliance, the attachment comprising: an air inlet; a primary air outlet; first and second secondary air outlet arrangements, each comprising a curved surface portion and a secondary air outlet arranged to direct air over the curved surface portion in use, wherein air is directed over the curved surface portion of the first secondary air outlet arrangement in an anticlockwise direction, and airflow is directed over the curved surface portion of the second secondary air outlet arrangement in a clockwise direction; a body defining the primary air outlet and the first and second secondary air outlet arrangements; and an air guide arrangement moveable relative to the body between a first air guide position to direct air from the air inlet to the primary air outlet, and a second air guide position to direct air from the air inlet to each of the secondary air outlets of the first and second secondary air outlet arrangements. Accordingly, the attachment may be used in different operating modes depending on the position of the air guide arrangement, providing airflow of differing characteristics, even with the same air flow rate at the air inlet. With the air guide arrangement in the second air guide position to direct air through the secondary air outlets, the attachment is in a second operating mode, according to which a gentle, diffused airflow may be generated. With the air guide arrangement in the first air guide position to direct air through the primary air outlet, the attachment is in a first operating mode, according to which a stronger, more concentrated airflow may be generated. The first secondary air outlet arrangement comprises a first curved surface portion and a first secondary air outlet arranged relative to the first curved surface portion for directing air along the first curved surface portion in use. Similarly, the second secondary air outlet arrangement comprises a second curved surface portion and a second secondary air outlet arranged relative to the second curved surface portion for directing air along the second curved surface portion in use. In use, airflows from the respective secondary air outlets may collide at a position downstream from the respective secondary air outlets and travel away from (such as in a radial direction) the attachment as a combined airflow. Directing airflow simultaneously in opposite directions around the attachment in this way may result in the combined airflow having a lower velocity and being a gentler airflow experienced by the user, compared to airflow exiting the primary air outlet directly. For example, the combined airflow may be wider than a width of the primary air outlet. To avoid confusion, the term “downstream” corresponds to the direction of airflow exiting an outlet in use Providing airflow through the secondary air outlets without first directing the airflow through the primary air outlet may enable the primary air outlet to be shaped and sized most suitably for its use. Optionally, air is directed in use over the curved surface portion of each of the secondary air outlet arrangements in a direction towards the primary air outlet. Optionally, the attachment is elongate and, when viewed from one longitudinal end of the attachment, the secondary air outlet of the first secondary air outlet arrangement is arranged relative to the curved surface portion of the first secondary air outlet arrangement so as to direct air in an anticlockwise direction along the curved surface portion of the first secondary air outlet arrangement in use, and the secondary air outlet of the second secondary air outlet arrangement is arranged relative to the curved surface portion of the second secondary air outlet arrangement so as to direct air in a clockwise direction along the curved surface portion of the second secondary air outlet arrangement in use. Optionally, the attachment is configured so that the air guide arrangement is rotatable 180 degrees relative to the body between the first and second air guide positions. Optionally, the first and second air guide positions are 180 degrees apart from each other. This may enable a user to easily ascertain an operating mode in which the attachment is operating. Optionally, the air guide arrangement is positionable at the first air guide position relative to the body to direct air from the air inlet to the primary air outlet and to restrict (such as prevent) air from passing from the air inlet to the secondary air outlets of the first and second secondary air outlet arrangements. This may increase an amount of air that is emitted through the primary air outlet when the air guide arrangement is at the first air guide position in use, as compared to a comparative arrangement in which air is emitted simultaneously from the primary air outlet and the secondary air outlets. Optionally, the air guide arrangement is positionable at the second air guide position relative to the body to direct air from the air inlet to the secondary air outlets of the first and second secondary air outlet arrangements and to restrict (such as prevent) air from passing from the air inlet to the primary air outlet. This may increase an amount of air that is emitted through the secondary air outlets when the air guide arrangement is at the second air guide position in use, as compared to a comparative arrangement in which air is emitted simultaneously from the primary air outlet and the secondary air outlets. Optionally, the air guide arrangement is arranged within the body. Arranging the air guide arrangement within, or inside, the body may help to reduce a possibility of a user’s hair getting trapped between relatively moving components of the attachment, in use. Optionally, the first and second secondary air outlet arrangements are at respective fixed positions relative to the primary air outlet. This may simplify construction and operation of the attachment, as compared to a comparative attachment in which the respective secondary air outlets are movable relative to the primary air outlet. Optionally, the curved surface portion of each of the second secondary air outlet arrangements extend from the respective secondary air outlets to the primary air outlet. This may increase surface areas of the respective curved surface portions. Optionally, the curved surface portion of each of the secondary air outlet arrangements are fixed in position relative to the respective secondary air outlets of the secondary air outlet arrangements. This may simplify construction and operation of the attachment, as compared to a comparative attachment in which the respective secondary air outlets and the respective curved surface portions are relatively movable. Such a static arrangement may enable the curved surface portions to be shaped so as to direct airflows from the secondary air outlets, in use, in desired manners without needing to accommodate for relative movement of the secondary air outlets and the curved surface portions. Optionally, the curved surface portions are separated from each other by a protruding portion of the body that defines the primary air outlet. Optionally, the curved surface portions are respective portions of a continuous curved surface. Optionally, the attachment comprises a user interface operable by a user to cause movement of the air guide arrangement between the first and second air guide positions. 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 air guide arrangement to change an operating mode of the attachment. The user interface may comprise a touchscreen located on the attachment. Optionally, the user interface comprises an element, such as a handle, toggle or high-friction gripping surface, on an outer surface of the body, which element may be actuated by the user to cause the movement of the air guide arrangement between the first and second air guide positions. Optionally, the user interface comprises an element that is rotatable by the user about a user interface axis between first and second user interface positions relative to the body to cause the movement of the air guide arrangement between the first and second air guide positions. Such a rotatable element may be space efficient and intuitive for a user to use. Optionally, the attachment is configured so that the element of the user interface is rotatable 180 degrees relative to the body between the first and second user interface positions. Optionally, the first and second user interface positions are 180 degrees apart from each other. This may enable a user to easily ascertain an operating mode in which the attachment is operating. Optionally, the air guide arrangement is rotatably connected to the body so as to be rotatable about an air guide arrangement axis between the first and second air guide positions. Such an arrangement may be simple and space efficient. Optionally, the user interface axis is parallel to, or coincident with, the air guide arrangement axis. This may help the attachment to be compact. Optionally, each of the curved surface portions are curved about a common axis. Optionally, each of the curved surface portions are curved about a common axis that is parallel to, or coincident with, the air guide arrangement axis. This may help the attachment to be compact. Optionally, each of the curved surface portions comprise a Coanda surface or a Coanda surface portion, for example a convex surface or convex surface portion along which airflow is attached as a result of the Coanda effect in use. Optionally, each of the curved surface portion is substantially smooth and uninterrupted in form, for example free of projections and / or recesses. This may enable hair to wrap around the curved surface portions in use and / or to help avoid hair snagging on the respective curved surface portions. Optionally, one, or each, of the curved surface portions has a substantially constant radius of curvature between the respective secondary air outlet and the primary outlet. This may help styling to be performed consistently along a tress of hair. Optionally, one, or each, of the curved surface portions subtends an angle of at least eighty degrees. This may help styling to be performed consistently along a tress of hair and / or relatively quickly, as compared to a comparative attachment in which each of the curved surface portions subtends an angle of less than eighty degrees. Optionally, each of the curved surface portions has a radius of curvature in the region of 10mm to 60mm. This may be particularly effective in generating an airflow along each of the respective curved surface portions that results in respective first forces to attract hair toward the respective curved surface portions, and respective second forces to push hair away from the respective curved surface portions. Optionally, the body is generally cylindrical and the primary air outlet is configured to direct airflow exiting the primary air outlet in a generally radial direction, in use. That is, the body may be configured such that airflow exits the primary air outlet in a direction normal to an outer surface of the body in which the primary air outlet is defined. This may simplify operation of the attachment when drying hair with the air guide arrangement in the first air guide position, since the hair can be dried by the airflow at any position radially outwards of the primary air outlet. Optionally, the air guide arrangement comprises a plurality of air guide elements that are offset relative to each other in first and second directions, the first and second directions being perpendicular to each other, and arranged to direct portions of an airflow that arrives, in use, at the air guide arrangement from the air inlet to respective portions of the primary air outlet, when the air guide arrangement is positioned at the first air guide position. This may cause airflow emitted from the primary air outlet to be more evenly spread over a full extent of the primary air outlet. When the air guide arrangement is positioned at the second air guide position, the air guide elements may direct portions of an airflow that arrives, in use, at the air guide arrangement from the air inlet to respective portions of the secondary air outlets. Each of the air guide elements may comprise a concave surface for turning airflow. This may help maintain more laminar air flow. Optionally, the body comprises first and second channels, such as respective arced surfaces, for channelling airflow from the air guide arrangement across the respective curved surface portions. This may help to reduce airflow separation to maintain more laminar airflow. Optionally, each of the secondary air outlets are substantially equal in size and shape such that, in use with the air guide arrangement positioned at the second air guide position, airflow from the air inlet is split substantially equally between the secondary air outlets to provide substantially equal flow rates and airflow velocities across the respective curved surface portions. This may help to ensure that airflows from the respective secondary air outlets collide and combine at a position substantially equidistant from the respective secondary air outlets. This may help a user to identify a direction of the combined airflow. Further, this may also help to ensure even styling on both sides of the head when the air guide arrangement is positioned at the second air guide position. Optionally, each of the secondary air outlets comprise a rectangular slot. This may provide more laminar airflows across the respective curved surface portions and / or allow greater areas of hair to be contacted by the airflows across the respective curved surface portions and thus styled by the attachment. Optionally, each of the secondary air outlets are 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 through the air inlet, thereby ensuring that, with the air guide arrangement positioned at the second air guide position, airflows are generated along the respective curved surface portions that result in respective first forces to attract hair toward the respective curved surface portions, and respective second forces to push hair away from the respective curved surface portions. This may additionally, or alternatively, provide a simpler attachment with fewer moving parts, and hence a reduced risk of failure, compared to an attachment with variable secondary air outlets. Optionally, the attachment comprises guide walls for guiding airflows along each of the curved surface portions, the guide walls upstanding from the curved surface portions. This may inhibit ambient air from impacting on regions of negative pressure generated by air flowing along the curved surface portions in use, and / or may result in increased attraction of hair toward the curved surface portions compared to, for example, a similar arrangement that does not utilise such guide walls. Optionally, the guide walls are of a height, measured from the curved surface portions, substantially equal to a height of the respective secondary air outlets from the respective curved surface portions. This may ensure that negative pressure regions are maintained along substantially the entire height of respective jets of air that exit the respective secondary air outlets in use. Optionally, the attachment comprises a retention mechanism for retaining the air guide arrangement in one of the first and second air guide positions in the absence of an applied force to the air guide arrangement by a user of the attachment. This may allow a user to change an orientation of the attachment without the air guide arrangement inadvertently moving between the first and second air guide positions. Optionally, the retention mechanism comprises an anchoring element for retaining the air guide arrangement in one of the first and second air guide positions. For example, the anchoring element may comprise a sprung plunger in one of the air guide arrangement and the body, the sprung plunger configured to engage with a recess in the other of the air guide arrangement and the body, when the air guide arrangement is in the one of the first and second air guide positions. For example, the sprung plunger may be biased from the one of the air guide arrangement and the body toward the other of the body and the air guide arrangement. The anchoring element may increase a force required to move the air guide arrangement between the first and second air guide positions, which may help to prevent inadvertent movement of the air guide arrangement. Optionally, the attachment comprises an alert module configured to alert a user of a position of the air guide arrangement relative to the body. This may help a user to know which operating mode the attachment is operating in. For example, the alert module may provide a first indicium to indicate when the air guide arrangement is in the first air guide position and thus the attachment is in a first operating mode, and a second, different indicium when the air guide arrangement is in the second air guide position and thus the attachment is in a second operating mode. The alert module may comprise at least one of a haptic feedback module, a visual indicium, and an aural indicium. This may ensure that an alert is provided to a user irrespective of whether the attachment is visible to the user. Optionally, the attachment comprises a heater for heating the airflow. This may provide increased styling flexibility and enable the airflow to provide an improved drying function. Optionally, the attachment comprises an elongate air outlet having an elongate mouth with a central axis that passes through the elongate mouth from an upstream end of the elongate mouth to a downstream end of the elongate mouth, wherein the elongate mouth is of constant width along at least a majority of its length and is both elongate and non-linear in a first plane normal to the central axis. Further optionally, the primary air outlet is an elongate air outlet. Optionally, a first elongate wall of the elongate mouth comprises a first wall portion that is non-linear in the first plane, and a second elongate wall, opposing the first elongate wall, of the elongate mouth comprises a second wall portion that is non-linear in the first plane. Optionally, an open cross-sectional area of the elongate air outlet reduces with distance along the central axis from the upstream end of the elongate mouth to the downstream end of the elongate mouth. A second aspect of the present invention provides a haircare appliance comprising: an air inlet; a primary air outlet; first and second secondary air outlet arrangements, each comprising a curved surface portion and a secondary air outlet arranged to direct air over the curved surface portions in use, wherein air is directed over the curved surface portion of the first secondary air outlet arrangement in an anticlockwise direction, and airflow is directed over the curved surface portion of the second secondary air outlet arrangement in a clockwise direction; an airflow generator for generating an airflow from the air inlet to the primary air outlet and to the secondary air outlets; a body defining the primary air outlet and the first and second secondary air outlet arrangements; and an air guide arrangement moveable relative to the body between a first air guide position to direct air from the air inlet to the primary air outlet, and a second air guide position to direct air from the air inlet to each of the secondary air outlets of the first and second secondary air outlet arrangements. This may provide any one or more of the advantages, described above, that are provided by the equivalent features of the attachment of the first aspect of the present invention. Optionally, the haircare appliance comprises a heater for heating the airflow. This may provide increased styling flexibility, and may, for example, enable the airflow to provide an improved drying function. The heater may be configured to operate at a particular temperature dependent on whether the air guide arrangement is in the first or second air guide position. Airflow of a lower temperature than an airflow temperature typically used for drying hair may be advantageous for providing the smooth finish described above during styling without inadvertent hair curling. Optionally, the haircare appliance comprises a handle unit within which the airflow generator is housed, and an attachment releasably attachable to the handle unit, the attachment comprising the body and the air guide arrangement. This may allow the functionality of the attachment described herein to be selectively provided by a user. A third aspect of the present invention provides an attachment for a haircare appliance, the attachment comprising an elongate air outlet having an elongate mouth with a central axis that passes through the elongate mouth from an upstream end of the elongate mouth to a downstream end of the elongate mouth, wherein the elongate mouth is of constant width along at least a majority of its length and is both elongate and non-linear in a first plane normal to the central axis. As used herein, “upstream end” and “downstream end” are with respect to a direction of airflow exiting the elongate air outlet in use. The elongate mouth being non-linear in the first plane normal to the central axis may result in improved mixing of air emitted from the elongate air outlet, and in particular improved mixing proximal to the elongate mouth, than in a comparative arrangement in which the elongate mouth is linear. It may additionally, or alternatively, create more turbulence in the air emitted from the elongate air outlet. Any one or more of these effects may improve efficacy of the air emitted from the elongate air outlet to dry hair. The mouth being elongate, rather than circular, may enable the elongate air outlet to emit air over a relatively wide area while enabling the elongate air outlet, and therefore the attachment as a whole, to be more compact. As used herein, the term “elongate” has its usual meaning of “long and narrow”. Accordingly, by the mouth being “elongate”, it is meant that the mouth is longer than it is wide, with the width of the mouth being measured between first and second elongate walls of the elongate mouth. For example, the mouth may be at least 100% longer than it is wide, at least 200% longer than it is wide, or at least 500% longer than it is wide. Optionally, a first elongate wall of the elongate mouth comprises a first wall portion that is non-linear in the first plane, and a second elongate wall, opposing the first elongate wall, of the elongate mouth comprises a second wall portion that is non-linear in the first plane. Further optionally, the first wall portion has a shape of a first sinusoid in the first plane, and the second wall portion has a shape of a second sinusoid in the first plane. Still further optionally, the first sinusoid has a first period, and the second sinusoid has a second period equal to the first period. Optionally, the first wall portion and the second wall portion are aligned relative to each other to provide the elongate mouth with a sinusoidal shape between the first wall portion and the second wall portion. This may cause airflow emitted from the elongate air outlet to be more evenly spread over the full length of the elongate mouth. It may additionally, or alternatively, reduce noise created by the air flow. Optionally, the first and second wall portions are non-linear in respective second and third planes parallel to the central axis. This may result in mixing of air emitted from the elongate air outlet to be improved. Further optionally, the first wall portion has a shape of a third sinusoid in the second plane, and the second wall portion has a shape of a fourth sinusoid in the third plane. This may reduce noise created by the air flow. Further optionally, the third sinusoid has a third period, and the fourth sinusoid has a fourth period equal to the third period. This may cause airflow emitted from the elongate air outlet to be more evenly spread over the full length of the elongate mouth. Further optionally, peaks and troughs of the third sinusoid are aligned with troughs and peaks, respectively, of the fourth sinusoid. This may cause airflow emitted from the elongate air outlet to be still further evenly spread over the full length of the elongate mouth. Optionally, an open cross-sectional area of the elongate air outlet reduces with distance along the central axis from the upstream end of the elongate mouth to the downstream end of the elongate mouth. This may facilitate concentration of the air flow through the elongate air outlet in use, which in turn may improve efficacy of the air emitted from the elongate air outlet to dry hair. Optionally, the attachment comprises an air inlet. Further optionally, the attachment comprises a secondary air outlet arrangement, the secondary air outlet arrangement comprising a curved surface portion and a secondary air outlet, a body defining the elongate air outlet and the secondary air outlet arrangement, the curved surface portion extending around the body from the secondary air outlet, and an air guide arrangement moveable relative to the body between a first position to enable air from the air inlet to pass through the elongate air outlet, and a second position to enable air from the air inlet to pass through the secondary air outlet of the secondary air outlet arrangement. Application of the elongate air outlet in such an attachment may enable air flow from the elongate air outlet to be perceptibly different in sound and / or flow characteristics from air flow emitted from the secondary air outlet, in use. This may help a user to recognise which of the air outlets is emitting air in use when the attachment is not in their line of sight, such as behind, or at the side of, their head. A fourth aspect of the present invention provides a haircare appliance comprising an air inlet, an elongate air outlet, and an airflow generator for generating an airflow from the air inlet to the elongate air outlet, wherein the elongate air outlet has an elongate mouth with a central axis that passes through the elongate mouth from an upstream end of the elongate mouth to a downstream end of the elongate mouth, and wherein the elongate mouth is of constant width along at least a majority of its length and is both elongate and non-linear in a plane normal to the central axis. This may provide any one or more of the advantages, described above, that are provided by the equivalent features of the attachment of the third aspect of the present invention. Optionally, the haircare appliance comprises a heater for heating the airflow. This may provide increased styling flexibility, and may, for example, enable the airflow to provide a drying function. Optionally, the haircare appliance comprises a handle unit within which the airflow generator is housed, and an attachment releasably attachable to the handle unit, the attachment comprising the air inlet and the elongate air outlet. This 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. For example, optionally the primary air outlet of the attachment of the first aspect of the present invention, or the primary air outlet of the hair care appliance of the second aspect of the present invention, is an air outlet having an elongate mouth with a central axis that passes through the elongate mouth from an upstream end of the elongate mouth to a downstream end of the elongate mouth, wherein the elongate mouth is of constant width along at least a majority of its length and is both elongate and non-linear in a first plane normal to the central axis. Further optionally, such an air outlet having an elongate mouth may have any or all of the features that are described above as optional features of the elongate air outlet of the attachment of the third aspect of the present invention. Similarly, the haircare appliances of the respective second and fourth aspects of the present invention may have any or all of the features that are described above as optional features of the attachments of the respective first and third aspects of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 shows a schematic front view of a haircare appliance, in which an attachment of the haircare appliance is detached from a handle unit of the haircare appliance; Figure 2 shows a schematic front view of the haircare appliance of Figure 1, in which the attachment is attached to the handle unit; Figure 3 shows a schematic cross-sectional view through the handle unit of the haircare appliance of Figure I; Figure 4 shows a schematic perspective view of the attachment of the haircare appliance of Figure 1; Figure 5 shows a schematic side view of the attachment of Figure 4; Figure 6 shows a schematic view illustrating forces created by airflow through the attachment of Figures 4 and 5 in use with an air guide arrangement of the attachment in a second air guide position and the attachment therefore in a second operating mode; Figure 7 shows a schematic front view of the attachment of Figures 4 and 5, illustrating the attachment with the air guide arrangement of the attachment in a first air guide position and the attachment therefore in a first operating mode; Figure 8 shows a schematic cross-sectional view of the attachment at the section line shown in Figure 7; Figure 9 shows a schematic front view of the attachment of Figures 4 and 5, illustrating the attachment with the air guide arrangement in the second air guide position and the attachment therefore in the second operating mode; Figure 10 shows a schematic cross-sectional view of the attachment at the section line shown in Figure 9; Figure 11 shows a schematic exploded view of the air guide arrangement of the attachment; Figure 12 shows a schematic cross-sectional view illustrating an attachment with the air guide arrangement of the attachment in a first air guide position and the attachment therefore in a first operating mode; and Figure 13 shows a schematic view of the attachment of Figure 12, with the air guide arrangement in a second air guide position and the attachment therefore in a second operating mode. DETAILED DESCRIPTION A haircare appliance 10 according to an embodiment of the present disclosure is shown schematically in Figures 1 and 2. The haircare appliance 10 comprises a handle unit 12 and an elongate attachment 100 removably attachable to the handle unit 12. Figure 1 shows the attachment 100 detached from the handle unit 12, and Figure 2 shows the attachment 100 attached 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 3. 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 in use, and an air outlet 24 through which the airflow is discharged from the housing 14 in use. The airflow generator 16 is housed within the housing 14 and comprises an impeller 26 that is arranged to be driven by an electric motor 28. The airflow generator 16 is configured to generate airflow at a flow rate in the region of 5 to 15 L / S. The heater 18 is also housed within the housing 14 and comprises heating elements 30 to selectively heat the airflow. The control unit 20 comprises electronic circuitry for a user interface 32a, 32b and a control module 34. The user interface 32a, 32b is provided on an outer surface of the housing 14 and is used to power the haircare appliance 10 on and off, to select a flow rate (for example high, medium and low), and to select an airflow temperature (for example hot, medium or cool). In the example of Figures 1 and 2, the user interface 32a, 32b comprises a plurality of sliding switches, but other forms of user interface 32a, 32b, 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 32a, 32b. For example, in response to inputs from the user interface 32a, 32b, 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 4-5 and 7-11. The attachment 100 comprises an elongate body 102 and an air guide arrangement 150 (see Figures 7, 8, 10 and 11) arranged within the body 102 and rotatably connected to the body 102. The body 102 defines an air inlet 104, a primary air outlet 106, and first and second secondary air outlet arrangements 110, 120 at respective fixed positions relative to the air inlet 104 and the primary air outlet 106. The first secondary air outlet arrangement 110 (see Figures 7 to 10) comprises a first curved surface portion 112 and a first secondary air outlet 114 that is integrally moulded with, and therefore fixed in position relative to, the first curved surface portion 112. The second secondary air outlet arrangement 120 comprises a second curved surface portion 122 and a second secondary air outlet 124 that is integrally moulded with, and therefore fixed in position relative to, the second curved surface portion 122. The body 102 has a generally cylindrical portion 102a and a generally triangular-prism-shaped portion 102b. The generally cylindrical portion 102a has a central longitudinal axis 103 and comprises the air inlet 104, an elongate protruding portion 105 that defines the primary air outlet 106, and the first and second curved surface portions 112, 122. The triangular-prism-shaped portion 102b is to one lateral side of the generally cylindrical portion 102a, is fixed in position relative to the generally cylindrical portion 102a, and has a central longitudinal axis that is parallel to the central longitudinal axis 103 of the generally cylindrical portion 102a. The triangular-prism-shaped portion 102b of the body comprises the first and second secondary air outlets 114, 124. The first and second secondary air outlet arrangements 110, 120 will be discussed in more detail, and then attention will turn to the primary air outlet 106. The first and second curved surface portions 112, 122 extend around the body 102 from respective first ends 112a, 122a of the curved surface portions 112, 122 to respective second, opposite ends 112b, 122b of the curved surface portions 112, 122. The respective first ends 112a, 122a of the curved surface portions 112, 122 are at, or immediately adjacent to, the secondary air outlets 114, 124. The respective second ends 112b, 122b of the curved surface portions 112, 122 are at, or immediately adjacent to, respective sides of the elongate protruding portion 105 that defines the primary air outlet 106. Each of the curved surface portions 112, 122 is convex with a constant radius of curvature (of about 19mm) between its first and second ends 112a, 112b, 122a, 122b, subtends an angle of about 120 degrees, is smooth and uninterrupted in form, and is curved about the central longitudinal axis 103. The first secondary air outlet 114 is a rectangular slot of fixed dimensions that is arranged relative to the first curved surface portion 112 so as to direct air in an anticlockwise direction (as Figure 10 is drawn) along the first curved surface portion 112 in use. Conversely, the second secondary air outlet 124 is a rectangular slot of fixed dimensions that is arranged relative to the second curved surface portion 122 so as to direct air in a clockwise direction (as Figure 10 is drawn) along the second curved surface portion 122 in use. The secondary air outlets 114, 124 are equal in size and shape. The triangular-prism-shaped portion 102b comprises two arced surfaces 115, 125 for channelling airflow from the air guide arrangement 150 to the secondary air outlets 114, 124 and thus across the curved surface portions 112, 122. Therefore, airflow from the air inlet 104 is split equally between the first and second secondary air outlets 114, 124 to provide substantially equal flow rates and airflow velocities therefrom. The attachment 100 has a pair of guide walls 108 for guiding airflows along the first and second curved surface portions 112,122. The guide walls 108 are comprised in the generally cylindrical portion 102a of the body 102 and are spaced apart in the direction of the central longitudinal axis 103. The guide walls 108 are upstanding from the first and second curved surface portions 112, 122 and are of a height, measured from the respective first and second curved surface portions 112, 122, equal to that of the first and second secondary air outlets 114, 124 and that of the elongate protruding portion 105. The first and second curved surface portions 112, 122 are separated from each other by the elongate protruding portion 105 of the body 102. Accordingly, the first and second curved surface portions 112, 122 of the body 102 are located at the bottom of respective recesses or channels between the elongate protruding portion 105, the guide walls 108, and the first and second secondary air outlets 114, 124. The inventors of the present application have found that airflows emitted from the first and second secondary air outlets 114,124 attach to the respective first and second curved surface portions 112,122 via the Coanda effect. Reference is made to Figure 6, which is a schematic illustration of the interaction of forces at the first curved surface portion 112, although the same principal applies at the second curved surface portion 122. 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 first curved surface portion 112 by a force F PI.JLL, as a result of a negative pressure region generated by the airflow from the first secondary air outlet 114 over the first curved surface portion 112. 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 first curved surface portion 112 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 first curved surface portion 112. 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, i.e., 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 styling 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 airflows from the first and second secondary air outlets 114, 124 of the attachment 100. In particular, too great a velocity may result in shorter hairs sticking to the associated curved surface portion 112, 122 and hence not being pushed away through longer hairs, whilst too low a velocity may not be sufficient to attract longer hairs to the associated curved surface portion 112, 122 in the first instance. Each of the first and second air secondary outlets 114, 124 has a smaller open cross-sectional area than an open cross-sectional area of the primary air outlet 106. This provides an increase in velocity of airflow at the first and second air secondary outlets 114, 124, compared with a velocity of airflow from the primary air outlet 106 for the same air flow rate at the air inlet 104, and thus helps enable the Coanda effect to be used. In use, as denoted by the dashed arrows 101 in Figure 10, airflow from the first and second secondary air outlets 114, 124 collides and travels away from the attachment 100 as a combined airflow. This combined airflow, well downstream of the first and second secondary air outlets 114, 124, is wider than a width of the primary air outlet 106 so that, for the same flow rate at the air inlet 104, a lower air velocity is achieved compared to when airflow is emitted from the primary air outlet 106. As such, this combined airflow may be used to gently dry the user’s hair. Accordingly, airflows emitted from the first and second secondary air outlets 114, 124 may be used individually, for styling a user’s hair, or together, for gently drying the user’s hair. As mentioned above, the first and second secondary air outlets 114, 124 are substantially equal in size and shape. Accordingly, the airflows from the first and second secondary air outlets 114, 124 collide proximate to the primary air outlet 106 and travel away from the attachment 100 as a combined airflow in a radial direction of the attachment 100, with respect to the central longitudinal axis 103. It will be appreciated that, in other embodiments, the secondary air outlets 114,124 may be of differing size and / or shape such that the airflows collide at a different position relative to the primary air outlet 106. The primary air outlet 106 is of a different shape to each of the first and second secondary air outlets 114, 124. The primary air outlet 106 is also arranged relative to the rest of the body 102 so as to direct airflow exiting the primary air outlet 106 in a generally radial direction, with respect to the central longitudinal axis 103. More specifically, the primary air outlet 106 comprises an elongate mouth having opposing first and second elongate walls 106a, 106b. As shown in Figures 4, 5 and 8, the elongate mouth has a central axis X that passes through the elongate mouth from an upstream end of the elongate mouth to a downstream end of the elongate mouth. As best seen in Figures 8 and 10, an open cross-sectional area of the primary air outlet 106 reduces with distance along the central axis X from the upstream end of the elongate mouth to the downstream end of the elongate mouth. As best seen in Figures 7 and 9, a portion of the first elongate wall 106a has a shape of a first sinusoid in a first plane that is normal to the central axis X and parallel to the central longitudinal axis 103. Similarly, a portion of the second elongate wall 106b also has a shape of a second sinusoid in that first plane. The first and second sinusoids have equal periods and are aligned relative to each other to provide the elongate mouth with a sinusoidal shape in the first plane between the first and second elongate walls 106a, 106b and to provide the elongate mouth with a constant width along a majority of its length. As best seen in Figure 5, the portions of the first and second elongate walls 106a, 106b also have shapes of respective third and fourth sinusoids in respective second and third planes that are parallel to the central axis X and parallel to the central longitudinal axis 103. These third and fourth sinusoids have equal periods but, looking in a direction normal to the second and third planes, peaks and troughs of the third sinusoid are aligned with troughs and peaks, respectively, of the fourth sinusoid. As a result of this geometry of the primary air outlet 106, airflow emitted from the primary air outlet 106 in use is well spread over the full length of the elongate mouth, well mixed and turbulent, and creates less noise than an outlet of equivalent size but straight opposing elongate walls. Efficacy of the attachment 100 to dry hair quickly using airflow from the primary air outlet 106 is therefore improved, without being too disturbing to the user. Accordingly, an airflow emitted from the primary air outlet 106 may be used to dry the user’s hair quickly, such as before using airflows emitted from the first and second secondary air outlets 114, 124 to style the user’s hair. The air guide arrangement 150 will now be described, with reference primarily to Figures 7 to 11. The air guide arrangement 150 comprises a set of six air guide elements 151-156, a frame 157 connecting the air guide elements 151-156 to each other, and an elongate casing 158 within which the frame 157 and the air guide elements 151-156 are fixed, in use. The frame 157 and the air guide elements 151-156 are integrally formed. The casing 158 has a circumferential side (or wall) having an elongate axially extending slot 159 therethrough, which slot 159 subtends an angle of about twenty degrees about the central longitudinal axis 103. Figure 11 shows the frame 157 and the casing 158 in a disassembled state. These are assembled during manufacture of the attachment 100 by inserting the frame 157 into the casing 158 in the direction of arrow A in Figure 11. In the assembled attachment 100, the air guide elements 151-156 are offset relative to each other both in a first direction, parallel to the central longitudinal axis 103, and in a second direction, perpendicular to the central longitudinal axis 103. Each of the air guide elements 151-156 comprises a concave surface. These concave surfaces are orientated relative to the air inlet 104 so that, in use, parallel portions of a bulk airflow from the air inlet 104, travelling parallel to the central longitudinal axis 103, hit respective ones of the concave surfaces of the air guide elements 151-156 and are turned through about ninety degrees by the concave surfaces so as to be directed through the elongate slot 159 of the casing 158. This may enable the handle unit 12 to extend orthogonally relative to the air outlets 106, 114, 124, which may provide greater flexibility in design, and better ergonomics, than, for example a haircare appliance where the air outlets are aligned with a handle unit of the haircare appliance. Depending on the position of the air guide arrangement 150 relative to the body 102, and thus an operating mode of the attachment 100, these airflow portions are thus directed from the slot 159 to the primary air outlet 106 or to the two arced surfaces 115, 125 for subsequent passage through the secondary air outlets 114, 124. The air guide arrangement 150 is rotatably connected to the body 102 so as to be rotatable 180 degrees about the central longitudinal axis 103 between first and second positions, which are 180 degrees apart from each other. When the air guide arrangement 150 is in the first position, as shown in Figures 7 and 8, the concave surfaces of the air guide elements 151-156 and the slot 159 face the primary air outlet 106, so that the air guide elements 151-156 are oriented to direct air from the air inlet 104 to the primary air outlet 106. Meanwhile, a solid portion of the casing 158 blocks a path between the air inlet 104 and the two arced surfaces 115, 125 to restrict or prevent air from passing from the air inlet 104 to the secondary air outlets 114, 124. On the other hand, when the air guide arrangement 150 is in the second position, as shown in Figures 9 and 10, the concave surfaces of the air guide elements 151-156 and the slot 159 face the two arced surfaces 115, 125, so that the air guide elements 151-156 are oriented to direct air from the air inlet 104 to the secondary air outlets 114, 124, and the solid portion of the casing 158 blocks a path between the air inlet 104 and the primary air outlet 106 to restrict or prevent air from passing from the air inlet 104 to the primary air outlet 106. To control the position of the air guide arrangement 150 relative to the body 102, and thus the operating mode of the attachment 100, the attachment 100 has a rotatable knob 160 located at a longitudinal end of the body 102 opposite from the air inlet 104. The knob 160 is fixedly connected to the air guide arrangement 150, so that the air guide arrangement 150 rotates with the knob 160. The knob 160 is rotatable 180 degrees about the central longitudinal axis 103 of the attachment 100 between first and second user interface positions relative to the body 102, which are 180 degrees apart from each other. The knob 160 is shown in the first user interface position in Figures 1,2 and 7, and in the second user interface position in Figure 9. Rotation of the knob 160 from the first user interface position to the second user interface position causes movement of the air guide arrangement 150 from its first position to its second position, i.e., from the first air guide position to the second air guide position. Conversely, rotation of the knob 160 from the second user interface position to the first user interface position causes movement of the air guide arrangement 150 from its second position to its first position, i.e., from the second air guide position to the first air guide position. When the knob 160 is at the first user interface position, a marking (not shown) on the knob 160 is aligned with a first marking (not shown) on the longitudinal end of the body 102. Conversely, when the knob 160 is at the second user interface position, the marking on the knob 160 is aligned with a second marking (not shown) on the longitudinal end of the body 102. Accordingly, the user is alerted to the position of the air guide arrangement 150 relative to the body 102, and therefore they know which operating mode the attachment 100 is operating in. The attachment 100 also has a retention mechanism in the form of a sprung plunger (not shown) fixedly mounted at a longitudinal end of the casing 158 of the air guide arrangement 150 and a pair of recesses (not shown) in an inside face of a longitudinal end of the generally cylindrical portion 102a of the body 102. The recesses are circumferentially offset from each other by 180 degrees about the central longitudinal axis 103. The sprung plunger is dimensioned and located so as to engage with one of the recesses when the air guide arrangement 150 is in the first position relative to the body 102, and so as to engage with the other of the recesses when the air guide arrangement 150 is in the second position relative to the body 102. When the sprung plunger is engaged with either one of the recesses, this engagement retains the air guide arrangement 150 in position relative to the body 102 in the absence of a force being applied to the knob 160 by the user. Upon application of a suitably large rotational force on the knob 160, relative rotational movement between the sprung plunger and an edge of whichever recess the sprung plunger is engaged with drives the sprung plunger in a direction away from the longitudinal end of the generally cylindrical portion 102a of the body 102 against the inherent bias of the sprung plunger. This releases the sprung plunger from the recess, enabling the air guide arrangement 150 to rotate freely relative to the body 102 until the spring plunger engages with the other recess, at which point the air guide arrangement 150 is again retained in position relative to the body 102 by the retention mechanism until application of another sufficiently large rotational force to the knob 160 by the user. Operation of the haircare appliance 10 will now be briefly described. 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 12 to the air inlet 104 of the attachment 100. Airflow flows from the air inlet 104 of the attachment 100 through the body 102 and is directed by the concave surfaces of the air guide elements 151-156 towards the slot 159 of the casing 158 of the air guide arrangement 150. If the air guide arrangement 150 is in its first position, as shown in Figures 7 and 8, the airflow passes from the slot 159 to the primary air outlet 106, from which the airflow exits the body 102 in a radial direction of the body 102, with respect to the central longitudinal axis 103. If the air guide arrangement 150 is in its second position, as shown in Figures 9 and 10, the airflow passes from the slot 159 toward the two arced surfaces 115, 125 and then through the secondary air outlets 114, 124. The position of the air guide arrangement 150 relative to the body 102 thus determines the operating mode of the attachment 100. With the air guide arrangement 150 in its first position, the attachment 100 is operable in a first operating mode, which is a quick drying mode, and airflow exits the primary air outlet 106 towards the user’s hair. With the air guide arrangement 150 in its second position, the attachment 100 is operable in a second operating mode, which is a gentle drying and styling mode, and airflows are guided from the secondary air outlets 114, 124 over the first and second curved surface portions 112, 122 via the Coanda effect. Since the air guide arrangement 150 is within, or inside, the body 102, there is less chance of a user’s hair getting trapped between relatively moving components of the attachment 100, in use. In the quick drying mode, a profile of air directed towards the user’s head is more concentrated compared to the gentle drying or styling mode. That is, for the same airflow at the air inlet 104, a greater air velocity is achieved at the outlet in the quick drying mode. Thus, the quick drying mode and the gentle drying and styling mode provide different drying experiences to the user, for the same flow rate through the air inlet 104. Whilst particular examples have been described, it should be understood that these are illustrative examples only and that various modifications may be made without departing from the scope of the invention as defined by the claims. For example, although described herein as embodiments with attachments that are releasable from associated handle units, embodiments are also envisaged where the haircare appliance is a single-piece unit, for example taking the form of a combined handle unit and attachment. Also, while the illustrated first and second curved surface portions are separated from each other by the elongate protruding portion of the body of the attachment, in some other examples the first and second curved surface portions are respective portions of a single, continuous curved surface. In some such other examples, the primary air outlet is formed in, or through, the single, continuous curved surface. In some examples, the attachment comprises a heater for heating the airflow, instead of or in addition to the handle unit comprising a heater for heating the airflow. Furthermore, while in the illustrated embodiment the primary air outlet has an elongate mouth with a sinusoidal shape and a constant width along a majority of its length, in other embodiments the first and second elongate walls of the elongate mouth may comprise respective portions that are non-sinusoidal but still non-linear in the first plane normal to the central axis, so as to make the elongate mouth non-sinusoidal but still non-linear in the first plane. In further examples, the primary air outlet may have any other shape, such as polygonal, e.g., rectangular, or elliptical, e.g., circular. Referring to Figures 12 and 13, the second embodiment of the attachment 200 (referred to as the second attachment 200), is shown. Features of the second attachment 200 are essentially the same as the first attachment 100 described previously, and only the differences are discussed in detail for brevity. Like features for the second attachment 200 are given numerals incremented by 100 from the first attachment 100. The attachment 200 comprises a primary air outlet 206 and first and second secondary air outlet arrangements 210, 220. An air guide arrangement 250 is moveable relative to the body 202 between a first air guide position to enable air from the air inlet 204 (not shown) to pass through the primary air outlet 206, and a second air guide position to enable air from the air inlet 204 to pass through the secondary air outlets 214, 224 of the first and second secondary air outlet arrangements 210, 220. Air guide attachment 250 is external to the body 202. Air guide arrangement 250 comprises a primary cover member 271 moveable relative to the body 202 between a first air guide position to enable air from the air inlet 204 to pass through the primary air outlet 206 and a second air guide position to restrict air from passing through the primary air outlet 206. The primary cover member 271 may fully or partially restrict airflow through the primary outlet 206. Air guide arrangement 250 further comprises first and second secondary cover members 272a, 272b movable relative to the body 202 between a second air guide position to enable air from the air inlet 204 to pass through the secondary air outlets 214, 224 of the first and second secondary air outlet arrangements 210, 220, and a first air guide position to restrict air from passing through the secondary air outlets 214, 224. The first and second secondary cover members 272a, 272b may fully or partially restrict airflow through the secondary air outlets 214, 224. In this example, the primary cover member 271 and the secondary cover members 272a, 272b are flaps that are movably connected to the body 202 to control airflow through the primary air outlet 206 and the secondary air outlets 214, 224, respectively. The primary cover member 271 and the secondary cover members 272a, 272b may be slidably or pivotably connected to the body 202. In the first air guide position, the primary cover member 271 is positioned to allow air from the air inlet 204 to pass through the primary air outlet 206, and the secondary cover members 272a, 272b are positioned to restrict (or prevent) air from passing through the secondary air outlets 214, 224. That is, secondary cover members 272a, 272b obstruct secondary air outlets 214, 224, respectively. In the second air guide position, the primary cover member 271 is positioned to restrict (or prevent) air from the air inlet 204 to pass through the primary air outlet 206, and the secondary cover members 272a, 272b are positioned to allow air to pass through the secondary air outlets 214, 224. That is, the primary cover member 271 is positioned to obstruct the primary air outlet 206. In still further examples, an attachment or a haircare appliance may comprise a primary air outlet of any of the forms described herein, while the attachment or haircare appliance otherwise takes an entirely different form to that illustrated. For example, in some cases, one or both of the secondary air outlet arrangements may be omitted and / or the air guide arrangement may not be located within the body and / or the air guide arrangement may not be moveable relative to the body. For example, in some embodiments, the primary air outlet 5 may be the sole air outlet of the attachment or haircare appliance.

Claims

1. An attachment for a haircare appliance, the attachment comprising:an air inlet;a primary air outlet;first and second secondary air outlet arrangements, each comprising a curved surface portion and a secondary air outlet arranged to direct air over the curved surface portion in use, wherein air is directed over the curved surface portion of the first secondary air outlet arrangement in an anticlockwise direction, and airflow is directed over the curved surface portion of the second secondary air outlet arrangement in a clockwise direction;a body defining the primary air outlet and the first and second secondary air outlet arrangements; andan air guide arrangement moveable relative to the body between a first air guide position to direct air from the air inlet to the primary air outlet, and a second air guide position to direct air from the air inlet to each of the secondary air outlets of the first and second secondary air outlet arrangements.

2. The attachment according to claim 1, wherein the air guide arrangement is positionable at the first air guide position relative to the body to direct air from the air inlet to the primary air outlet and to restrict air from passing from the air inlet to the secondary air outlets of the first and second secondary air outlet arrangements.

3. The attachment according to claim 1 or claim 2, wherein the air guide arrangement is positionable at the second air guide position relative to the body to direct air from the air inlet to the secondary air outlets of the first and second secondary air outlet arrangements and to restrict air from passing from the air inlet to the primary air outlet.

4. The attachment according to any preceding claim, wherein the air guide arrangement is arranged within the body.

5. The attachment according to any preceding claim, wherein the first and second secondary air outlet arrangements are at respective fixed positions relative to the primary air outlet.

6. The attachment according to any preceding claim, wherein the curved surface portion of each of the secondary air outlet arrangements extends from the respective secondary air outlet to the primary air outlet.

7. The attachment according to any preceding claim, wherein the curved surface portion of each of the secondary air outlet arrangements is fixed in position relative to the respective secondary air outlets.

8. The attachment according to any preceding claim, comprising a user interface operable by a user to cause movement of the air guide arrangement between the first and second air guide positions.

9. The attachment according to claim 8, wherein the user interface comprises an element that is rotatable by the user about a user interface axis between first and second user interface positions relative to the body to cause the movement of the air guide arrangement between the first and second air guide positions.

10. The attachment according to any preceding claim, wherein the air guide arrangement is rotatably connected to the body so as to be rotatable about an air guide arrangement axis between the first and second air guide positions.

11. The attachment according to both claim 9 and claim 10, wherein the user interface axis is parallel to, or coincident with, the air guide arrangement axis.

12. The attachment according to claim 10 or claim 11, wherein each of the curved surface portions are curved about a common axis that is parallel to, or coincident with, the air guide arrangement axis.

13. The attachment according to any preceding claim, comprising an elongate air outlet having an elongate mouth with a central axis that passes through the elongate mouth from an upstream end of the elongate mouth to a downstream end of the elongate mouth, wherein the elongate mouth is of constant width along at least a majority of its length and is both elongate and non-linear in a first plane normal to the central axis.

14. The attachment according to claim 13, wherein a first elongate wall of the elongate mouth comprises a first wall portion that is non-linear in the first plane, and a second elongate wall, opposing the first elongate wall, of the elongate mouth comprises a second wall portion that is non-linear in the first plane.

15. The attachment according to claim 13 or claim 14, wherein an open cross-sectional area of the elongate air outlet reduces with distance along the central axis from the upstream end of the elongate mouth to the downstream end of the elongate mouth.

16. A haircare appliance comprising:an air inlet;a primary air outlet;first and second secondary air outlet arrangements, each comprising a curved surface portion and a secondary air outlet arranged to direct air over the curved surface portions in use, wherein air is directed over the curved surface portion of the first secondary air outlet arrangement in an anticlockwise direction, and airflow is directed over the curved surface portion of the second secondary air outlet arrangement in a clockwise direction;an airflow generator for generating an airflow from the air inlet to the primary air outlet and to the secondary air outlets;a body defining the primary air outlet and the first and second secondary air outlet arrangements; andan air guide arrangement moveable relative to the body between a first air guide position to direct air from the air inlet to the primary air outlet, and a second air guide position to direct air from the air inlet to each of the secondary air outlets of the first and second secondary air outlet arrangements.

17. The haircare appliance according to claim 16, comprising a handle unit within which the airflow generator is housed, and an attachment releasably attachable to the handle unit, the attachment comprising the body and the air guide arrangement.

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