Hair styling accessory

Abstract

A hair styling accessory comprises a body supporting a pair of jaws 104 which define a clamping space 106 between them. At least one of the jaws has a movable surface 120 configured to releasably clam

Description

BACKGROUND Conventional hair straighteners generally comprise a pair of movable elongate arms or jaws that each include an elongate clamping plate. The arms are movable between an open position in which hair to be straightened or styled is received between the arms, and a closed position in which hair is clamped between planar faces of the clamping plates. In some styles of hair straighteners, a user grips and squeezes a handle of the hair straighteners to pivot the arms together, which closes the clamping plates. In the closed position, the clamping plates are parallel and engaged across their planar faces. SUMMARY In accordance with examples of the invention, there is provided a hair styling accessory. The hair styling accessory comprises a body supporting a pair of jaws defining a clamping space between them for receiving a tress of hair, at least one of the jaws providing a movable surface configured to releasably clamp the tress of hair between the jaws. At least one of the jaws is provided with an internal chamber configured to receive a flow of air from an airflow inlet, and an airflow outlet. A porous structure configured to provide resistance to the flow of air is disposed in an airflow path from the airflow inlet to the airflow outlet. A porous structure within the airflow path provides resistance to the flow of air through the outlet, which may help to maintain a suitable pressure level within the internal chamber while allowing for a larger airflow outlet size. This may provide faster dry ing time, while reducing noise levels. In one example the porous structure may be disposed at an end of the internal chamber proximal to the airflow outlet. For example, the porous structure may be disposed within the internal chamber, closer to the airflow outlet than to the airflow inlet. When the porous structure is arranged closer to the airflow outlet, a suitable air pressure level may be maintained in a larger portion of the internal chamber than if the porous structure were arranged proximal to the airflow inlet. In other examples, the porous structure may be arranged at the airflow outlet or downstream of the airflow outlet. The airflow outlet may take various forms. In one example the airflow outlet may be elongate and extend in a direction along an axis which provides beneficial coverage across a width direction of a tress of hair. In such a configuration, the porous structure may also be an elongate structure that extends in a direction aligned with the axis of the airflow outlet, thereby to provide an airflow restriction along the length of the airflow outlet. The porous structure may take any suitable fonn to provide the beneficial functional effect. For example, it is envisaged that the porous structure could be formed from a length of an open-celled foam, of plastics or metal for example. Such a structure could be integrated into the body of the internal chamber, for example through 3D printing. Such a structure could be rod-like in form or any other suitable cross-sectional shape. In one example the porous structure may be a substantially planar member. For example, the planar member may be a mesh sheet. Such a structure can be suitably installed within the internal chamber so that the porous structure covers a mouth of the airflow outlet, such that air is forced to flow through the planar member. A mesh panel may be a suitable structure. A metal mesh panel may be more resilient to high temperature. More particularly, a chemically-etched metal mesh panel may provide a particular fine mesh size for the porous structure. The porous structure may have an open area percentage that is from about 10% to about 40%. Such a range may provide the most benefit of noise reduction from the hairstyling accessory without excessively restricting airflow through the air outlet. The jaw having the movable surface may comprise the internal chamber and the airflow outlet. In this example, the airflow outlet may be provided in the movable surface. In other examples, one of the jaws of the pair of jaws may comprise the movable surface, and the other of tire pair of jaws may comprise the internal chamber and the airflow outlet. The movable surface of the jaw may be actuatable by air pressure. Both jaws of the pair of jaws may-have a movable surface for clamping a tress of hair between them. BRIEF DESCRIPTION OF THE DRAWINGS Figure la is a perspective view of a hair sty ling accessory in an unclamped position; Figure lb is a perspective view of the hair styling accessory of Figure la in a clamped position; Figure 2a is a perspective view of a portion of the hair styling accessory of Figure la, illustrating a flow of air between jaws of the accessory in the clamped position; Figure 2b is a side view of the portion of the hair styling accessory shown in Figure 2a; Figure 2c is a plan view of the portion of the hair styling accessory shown in Figure 2a; Figure 3a is a front view of the hair styling accessory of Figure la, showing clamping members of the accessory in their clamped positions; Figure 3b is a cross-section taken through the front view of Figure 3a, in which the direction of air flow in a clamping space defined between the clamping members is illustrated; Figure 3c shows a porous structure in the form of a noise reduction mesh of the clamping members; Figure 4a shows a tress of hair received between jaws of the hair styling accessory of Figure la in an unclamped position; Figure 4b shows a tress of hair clamped between jaws of the hair styling accessory of Figure la in a clamped position; Figure 5 shows a view of a hair styling accessory which defines an attachment for a hair styling device; Figure 6a to 6c are various views of a second example of a hair styling accessory similar to that of the previous figures, but shown in an unclamped or 'open' position, Figures 7a to 7c are various views of the hair styling accessory of Figures 6a-6c but shown in a clamped or ‘closed’ position; Figure 8 is a plot of sound pressure level (y-axis) and frequency (x-axis) which demonstrates the acoustic output of the hair styling accessory'. DETAILED DESCRIPTION Figures la to 4b show a hair styling accessory 10 in accordance with a first embodiment. The hair styling accessory 10 comprises a body 12 and a pair of jaws 14 that are supported by the body 12. The jaws 14 define a clamping space 16 between them for receiving a tress of hair 18 (shown in Figures 4a and 4b) and are movable to releasably clamp the tress of hair 18 between the jaws 14 in use. Specifically, each jaw 14 is configurable or movable between an unclamped position shown in Figure la, and a clamped position shown in Figure lb. In the unclamped position, the jaws 14 are separated to allow a tress of hair 18 to be received in the clamping space 16. In the clamped position, the jaws 14 are arranged to clamp atress of hair 18 received in the clamping space 16. As will be explained in more detail later, the jaws 14 are actuated for movement using air pressure generated within or external to the hair styling accessory- 10. Each jaw 14 is generally elongate, having a first end 20 coupled to tire body 12 and a second end 22 remote from the body. Each jaw 14 comprises a clamping member 24 and a housing 26. Each clamping member 24 is moveably coupled to its associated housing 26. A chamber 28 is defined between each clamping member 24 and its associated housing 26. In use, air is delivered to the chambers 28 through airflow inlets 58 to actuate movement of the respective clamping member 24. At least a portion of this air may subsequently be delivered to the clamping space 16 for use in tire hair styling process. In this embodiment, the body 12 defines an elongate handle of the hair styling accessory 10. However, in other embodiments such as the second embodiment of Figure 5, the body 12 comprises an attachment portion 30 for attachment to a separate handle portion 32 to define an attachable accessory for a hair styling device 34. Each clamping member 24 is generally elongate in shape, and comprises an outer wall 36 defining first and second long edges, 38 and 40 respectively, an upper wall 42, a first end wall (not shown) and a second end wall 44. The clamping members 24 are pivotably coupled to their respective housings 26 at their first long edges 38. The second long edges 40 define clamping edges 41 for engaging and clamping atress of hair 18 in the clamped position. The upper wall 42 of each clamping member 24 extends generally perpendicularly from the second long edge 40 of the outer wall 36, and includes a protrusion 46 that engages with a corresponding protrusion 48 of the housing 26 in the clamped position to together define a limit stop 50. The limit stop 50 limits movement of the clamping members 24 in a clamping direction (i.e. the direction of movement of the clamping member 24 from its unclamped position towards its clamped position). Once engaged, the limit stop 50 prevents further movement of the clamping member 24 in the clamping direction, and guards against disengagement of the clamping member 24 from its housing 26. Referring now to Figures la and 3b in particular, the outer wall 36 of each clamping member 24 comprises a plurality of passages 52 that connect the chamber 28 to the clamping space 16. In use, air is delivered from the chamber 28 to the clamping space 16 via the passages 52. Each passage 52 terminates in an outlet 54 provided in an outer face 56 of the outer wall 36, and is located towards the clamping edge 41 of the clamping member 24. The passages 52 are arranged such that air entering the clamping space 16 from the passages 52 is directed generally away from the clamping edges 41 of the clamping members 24, and towards the first long edges 38 of the clamping members 24. For this, as illustrated in Figure 3b, each passage 52 has a generally arch-shaped crosssection. Also illustrated in Figure 3b is the direction of the flow of air, A, through and out of the archshaped passages 52. Ihe passages 52 are arranged side-by-side to extend generally across the entire length of the outer wall 36 in this embodiment, so as to enable air to be delivered to a tress of hair 18 clamped at any position in the clamping space 16. The arrangement and number of passages 52 could of course differ in other embodiments, however, and the accessory is not intended to be limited in this regard. For example, each clamping member 24 may include a single elongate passage 52 terminating in a single elongate outlet 54 extending generally across the entire length of the outer wall 36. It would also be possible for the number of passages 52 to differ from the number of outlets 54 such that, for example, multiple passages 52 terminate in a single outlet 54, or a single passage 52 terminates in multiple outlets 54. The arrangement of passages 52 and outlets 54 may differ for each clamping member 24. The hair styling accessory 10 further includes an air generating device (not shown) comprising a motor configured to produce a high-pressure air flow. A suitable pressure of flow may be between 3.5 and 7Kpa at 13.5L / s, purely by way of example. The air generating device is housed in the body 12 in this embodiment and forms part of the hair styling accessory 10, but could be external to the hair styling accessory 10 in other embodiments. For example, in the embodiment of Figure 5, the air generating device may be housed in the handle portion 32. In this example, therefore, it will be appreciated that the hair styling accessory 10 is a detachable component relative to the handle portion 32, which may be adapted to have other hair styling accessories attached to it such as a diffuser, a flow concentrator, and so on. In some embodiments, air generated by the air generating device is heated by a heating element before being delivered to the clamping space. To use the hair styling accessory 10, a user first places a tress of hair 18 in the clamping space 16 defined between the unclamped clamping members 24, as shown in Figure 4a. Although not shown, the clamping members 24 are biased towards the unclamped position by biasing means in the form of biasing springs. When the air generating device is turned off, the biasing means hold the clamping members 24 in their unclamped positions within the housing 26. To clamp the tress of hair 18 between the clamping members 24, the user actuates the jaws 14 by pressing a push button (not shown) provided on the body 12 of the hair styling accessory 10. Of course, in other embodiments the jaws 14 may be actuated via another suitable type of user interface such as a sliding switch. The jaw 14 may also be actuated automatically, without specific command from the user. For example, the clamping may be activated by a sensing system. The sensing system may be configured to sense when hair is placed between the jaws and then to activate clamping. The clamping may be activated after a predetermined time period to allow the user to place the hair between the jaws and then move their hands clear. The sensing system may also be configured to deactivate the clamping. For example, the sensing system may be configured to sense when hair has been pulled completely through the jaws such that the clamping can be released. The automatic clamping may be combined with manual clamping commanded by the user. When the push button is pressed into an "on’ position, an electronic activation signal is sent to the air generating device. Once activated, the air generating device generates a jet or flow of high-pressure air which is delivered to the chamber 28 of each jaw 14 via conduits (not shown) that connect an outlet (not shown) of the air generating device to airflow inlets 58 of the chambers 28. This jet of air forces the clamping members 24 to pivot from their unclamped positions to their clamped positions, overcoming the force of the biasing means and causing the chambers 28 to expand. The outer walls 36 of the clamping members 24 thereby move inwardly, in the direction of the clamping space 16, so that they come together to clamp a tress of hair between the clamping edges 41. The outer walls 36, therefore, provide a movable surface of the hair accessory 10 for releasably clamping a tress of air, when the accessory 10 is activated by air pressure. It should be noted that in some embodiments the air generating device may be activated separately to actuation of the jaws 14. That is, the air generating device may be activated initially without actuating the jaws 14, and the jaws 14 may be subsequently actuated by diverting airflow generated by the air generating device to the jaws 14, or by e.g. releasing retaining means (not shown in Figures 4a or 4b) configured to releasably hold the clamping members 24 in the unclamped position. In the clamped position shown in Figure 4b, the tress of hair 18 is clamped between the clamping edges 41 of the clamping members 24. The air pressure generated by the air generating device is such that, in this clamped position, the tress of hair 18 is firmly clamped between the clamping edges 41. A portion of the jet of air provided by the air generating device is delivered from the chambers 28 to the clamping space 16 for direct use in styling of the clamped tress of hair 18. In other embodiments, one or more separate jets of air to those delivered to the chambers 28 are delivered to the clamping space 16. In that case, the hair styling accessory 10 may include separate conduits for delivering air directly to the passages 52 from the air generating device, in addition to the conduits that deliver air to the chambers 28 from the air generating device. Although not shown, in some embodiments the hair styling accessory- 10 includes a heater, and air generated by the air generating device is heated by a heater before being delivered to the clamping space 16. As noted already, the passages 52 that deliver air to the clamping space 16 are arranged to direct air away from the clamping edges 41 and towards the first long edges 38 of the clamping member 24. This advantageously provides a straightening and smoothing effect on the tress of hair 18 in the clamping space 16, by directing a flow of air both towards and along the length of this tress of hair, rather than directly at and perpendicularly with respect the length of the tress of hair 18. Furthermore, the arrangement of Figure 4b reduces the likelihood of hairs being blown out of the clamping space 16 in use. With the tress of hair 18 clamped between the clamping edges 41, the user pulls the hair sty-ling accessory 10 along the length of the tress of hair 18 in a direction indicated by arrow D in Figure 4b, to straighten or style the tress of hair 18 as required. When the user wishes to release the tress of hair 18, they simply press the push button again, into an ‘off position, which causes an electronic signal to be sent to the air generating device to deactivate the air generating device. The air generating device stops delivering high pressure air to the jaws 14, and the clamping members 24 are no longer forced into the clamping position by this high-pressure air. The biasing means pull the clamping members 24 from the clamped position back to the unclamped position, and the hair styling accessory 10 is ready for use on another tress of hair 18. As mentioned above, in other examples, deactivation of the clamping may be achieved by way of a suitably configured sensing system that senses when no hair is between the jaws and, in response, deactivates clamping, by stopping air generation, for example. Having described the general configuration and functionality of the hair styling accessory 10 in Figures 1 to 5, a further aspect of the hair styling accessory 10 will now be expanded on in greater detail, with specific reference to Figure 3b. It will be appreciated from the above discussion that the clamping members 24 are actuated by air pressure that is present within the internal chamber 28. So, when the air generating device is activated, air is pumped into the chamber 28 which urges the clamping members 24 inwards such that the clamping edges 41 converge on one another, thereby clamping a tress of air between them, and which forces a flow of high velocity air ‘A' along the passages 52 and out of the outlets 54. The flow of air ‘A’ provides a straightening effect for the tress of hair. The presence of pressurised air within the chamber 28 and the high velocity airflow from the outlets 54 has been observed to be a source of noise emissions from the hair styling accessory 10. With a view to reducing the noise emissions from the hair styling accessory 10, a noise mitigating measure is shown in Figure 3b. As can be seen in the illustrated example, each porous structure 60 is located in a respective airflow path from the respective airflow inlet 58 to the respective airflow outlet 54. Each porous structure 60 is configured to provide resistance to the flow of air, such that noise emissions from the hair styling accessory 10 are reduced, in use. The porous structures 60 are configured so that a flow of air is able to pass through each structure, and therefore also to pass through the respective airflow outlet 54, but also to provide some resistance to airflow so that some pressurisation of the chambers 28 is retained. In the example of Figure 3b, a pair of porous structures 60 are provided, one for each of the internal chambers 28, and both of the porous structures 60 are identical. Therefore, for the purposes of this discussion, reference will be made to a single porous structure 60 for clarity although the skilled reader would appreciate that the discussion may relate to both porous structures 60. In summary, the porous structure 60 includes a porous member 62 and a support 64, in the illustrated example. The support 64 is in the form of a pair of opposed brackets 65 shaped with respective slots 66 for receiving a part of the porous member 62. The support 64 is attached to an upper end of the clamping member 28, at or near to the protrusion 46. The support 64 may be a different component to the clamping member 28 or may be an integral part of the clamping member 28, for example as would be the case if the clamping member 24 were formed from a moulding process with a moulded-in support 64. It should be noted that the form of clamping member 24 and support 62 shown in the Figures is merely exemplary. Tire support is configured and oriented so that it supports the porous member 62 in a position so that the porous member 62 extends across a mouth of the one or more passages 52. Preferably the porous member 62 extends across the mouth of the one or more passages 52 from one side to the other so as to cover the mouth of the one or more passages 52. The porous member 62 may therefore be elongated in shape so as to extend across multiple ones of the passages 52, in the case where there are a plurality of such passages 52 formed in the clamping member 24. In the illustrated example, the porous member 62 takes the form of a mesh sheet, and is shown m Figure 3c in isolation from the clamping member 24. The porous member 62 may be fabricated from different sheet materials with the required porosity. For example, the porous member 62 may be a polymeric mesh. However, in one example the porous member 62 is formed from a metal mesh, e.g. of stainless steel. A metal mesh such as a steel mesh is envisaged to be useful because may be better able to withstand high temperature environments. In this respect, it is possible that the air pumped into the chambers 28 is heated to a high temperature, for example above 100 degrees centigrade, so a metal mesh may be more robust than a polymeric mesh. Another reason why a metal mesh is considered to be useful is that it is possible to provide metal meshes with a very small pore size. This may be achieved by way of a chemically etched metal mesh, for example a chemically etched stainless steel mesh. Thickness of the mesh may be less than 1mm. by way of example only, for example between about 0.2mm and 1mm, and optionally around 0.3mm. In order to retain sufficient pressure within the internal chambers, a high pore density is advantageous, for example as would be achieved by way of an ultra-fine stainless steel woven mesh or a perforated steel mesh, as may be achieved by chemical etching. Various metals may be suitable, but an example is 304 stainless steel (ASTM) which is an alloy of iron chromium (18%) and nickel (8%) in order to provide useful corrosion resistance. Grade 316 stainless steel is another option that is considered acceptable, strictly by way of non-limiting example. The skilled person would appreciate that these example materials are exemplary and that other mesh materials may serve a comparable function. Pore density’ may be in the region of 30 to 600 pores per linear inch. As will be appreciated a variant of mesh size may serve to provide an acceptable characteristic and ‘tuning’ of the noise-reduction characteristic of the porous structure. In this connection, it is envisaged that an open area percentage (sometimes referred to in the art simply as the ‘open area’) of approximately 10% to 40% may be applicable for such a porous structure of the type described herein. As the skilled person would appreciate, there are various methodologies for determining the open area of a mesh sheet. For completeness, one methodology is shown in the inset panel in Figure 3c. For completeness, and as shown in Figure 3c, the open area percentage is given by the equation: _ n / c2 xioo . . Open area % =----- (1) ' Ut x u2 v ' In the above equation, the term ‘C’ is the edge length of a pore of the mesh, Ui is the distance between pore centres in adjacent pore rows, and IT is the distance between pore centres in adjacent pore columns. The above equation applies to meshes having generally square pores or apertures in a grid pattern, as is shown in Figure 3c. The skilled person would understand that other equations may apply to meshes with different forms of pores. The skilled person would be aware of other methodologies known in the art for determining open area value and porosities for other porous structures such as open-celled foams. Beneficially, the presence of the porous structures 60 provides a resistance to the flow of air through the airflow outlets 54 and associated passage 52 which would otherwise be provided by the geometry of the passage 52 and airflow outlets 54 themselves. Since a narrow passage 52 and / or airflow outlet 54 tends to increase airflow turbulence and therefore act as a noise source, the porous structures 60 allows for passages 52 and outlets 54 to be optimised to reduce airflow turbulence and generated noise. However, the presence of the porous structures 60 means that there is still sufficient pressure retained within the internal chambers 28 of the jaws. Figure 8 provides a graph showing the effects of the use of an exemplary porous structure. In Figure 8, the porous structure is planar in form with an open area of approximately 20%. Moreover, the porous structure used is a chemically etched metal mesh. Figure 8 provides two frequency domain plots which depict sound pressure level (y-axis) in Decibel against measured acoustic frequency (x-axis) in kHz (logarithmic scale). Line A represents the acoustic profile generated during operation of a hair styling accessory as described herein without the porous structure present in the internal chambers thereof, whereas Line B represents the acoustic profile during operation of a hair styling accessory as described herein with the porous structure present. As will be appreciated from Figure 8, the use of a porous structure, in this case being a metal mesh, in an upstream position relative to the airflow outlets 54 of the clamping members 24 helps to reduce the aerodynamically-induced noise of the high speed air as it flows through the airflow outlets 54. The reduction in noise can be seen from the overall drop in the FFT spectra between around 1kHz and about 10kHz, with a peak reduction of about 7dB between about 2kHz and 3kHz. Although the porous member 62 has been shown in the illustrated example as a mesh sheet, it should be appreciated that other forms would be acceptable. For example, it is envisaged that a porous rod, for example made from an open-celled metal foam may provide a similar functionality of allowing a high-velocity flow of air from the internal chamber, whilst retaining sufficient air pressure within the internal chamber for activation of the jaws. In the Figures described previously, the hair styling accessory 10 has a configuration in which the clamping members 24 are movable with respect to their respective housings 26 based on air pressure present within the internal chamber 28, wherein the respective housings 26 are fixed to and support by the body 12. An alternative configuration of hair styling accessory 100 will now be described with reference to Figures 6a-c and Figure 7a-c. Whereas the hair sty ling accessory 100 is shown in an unclamped or 'open' position in Figures 6a-c, the hair styling accessory 100 is shown in a clamped or ‘closed’ position in Figures 7a-c. The hair styling accessory7 100 that will be described below is similar in many respects to the hair styling accessory 10 described above. Therefore, this discussion will focus on the differences in configuration between the two hair styling accessories 10,100 and the significance of those differences. The hair styling accessoiy 100 comprises a body 102 and a pair of jaws 104 that are supported by the body 102. The jaws 104 define a clamping space 106 between them for receiving a tress of hair, and are movable to releasably clamp the tress of hair between the jaws 104 in use. Each jaw 104 is configurable or movable between an unclamped position shown in Figures 6a-c, and a clamped position shown in Figures 7a-c. In the unclamped position, the jaws 104 are separated to allow a tress of hair to be received in the clamping space 106. In the clamped position, the jaws 104 are arranged to clamp a tress of hair received in the clamping space 106. The movement of the jaws 104 is actuated using air pressure generated within or external to the hair styling accessory 100. Each jaw 104 is generally elongate, having a first end coupled to the body 102 and a second end remote from the body 102. Each jaw 104 comprises a clamping member 108 and a stationary member 110. In this embodiment, the clamping member 108 completely surrounds the stationary member 110, so the stationary member 110 cannot be seen from outside the device. Each clamping member 108 is moveably coupled to its associated stationary member 110. A suitable movable coupling (not shown) is provided at the body 102 to enable the clamping members 108 to pivot or move in relation to the stationary members 110. Respective internal chambers 112 are defined between each clamping member 108 and its associated stationary member 110. In use, air is delivered to the chambers 112 of the jaws 104 through airflow inlets 158 to actuate movement of the respective clamping member 108. At least a portion of this air may subsequently be delivered to the clamping space 106 for use in the hair styling process. In this example, the body 102 comprises an attachment portion 114 for attachment to a separate air generating device (such as handle portion 32 shown in Figure 5) to define an attachable accessory. Each clamping member 108 is generally elongate in shape, and comprises a front wall 120, an end wall 122 and a back wall 124. The top portion of the front wall 120 meets (e.g. being rigidly attached to) the top portion of the back wall 124 and the lower portion of the front wall 120 meets (e.g. being rigidly attached to) the lower portion of the back wall 124. Tire stationary member 110 is inside the clamping member 108, such that the clamping member 108 surrounds the stationary member 110. The top portions of the front walls 120 define clamping edges 126 for engaging and clamping a tress of hair in the clamped position. As can be seen from Figure 6c, the front wall 120 has a generally planar shape and the clamping edge 126 is at a slight angle to the plane of the front wall 120. This allows the clamping edges 126 of opposing clamping members 108 to be aligned when the clamping member 108 is in the clamped position. The end walls 122 of the clamping members 108 are angled with respect to the normal to the front wall 120 so as to provide a tapered opening to the clamping space 106 for receiving a tress of hair. The clamping members 108 are pivotably coupled to their respective stationary members 110 at the base of the front wall 122, as denoted by a pivot 125. In this embodiment, a spring, or biasing member (not shown), is provided to bias the clamping members 108 in the unclamped position. However, in alternative embodiments such a biasing member may be omitted. In a similar way to the example illustrated in Figures 1 to 5, the front walls 120 of the clamping members 108 move inwardly when the accessory is activated by a flow of pressurized air into the internal chambers 112, in the direction of the clamping space 106, so that they come together to clamp a tress of hair between the clamping edges 126. The front walls 120, therefore, provide respective movable surfaces of the hair accessory 10 for releasably clamping a tress of air, when the accessory' 100 is activated by air pressure. The back wall 124 in this embodiment has a curved, in particular convex, shape (although other shapes are envisaged). The stationary members 110 are also curved. As can be seen in Figures 6c and 7c, the curvature of the stationary member 110 matches tire curvature of the back wall 124 so that when the clamping member 108 is in the clamped position the curved surface of the stationary' member 110 abuts the curved inner surface of the back wall 124, yvhich acts as a limit stop to prevent the clamping members 108 moving any closer together. Each stationary member 110 also has a projection 128 that projects from the inner surface of the curved portion of stationary member 110. As shown in Figure 6c, this projection 128 is arranged to engage yvith the inner surface of the front wall 120 of the clamping member 108 yvhen in tire unclamped position. This acts as a limit stop to prevent the clamping member 108 moving further away from the clamping direction, thus acting against the biasing force of the biasing member. However, in alternative examples, the projection could be positioned on the inner surface of the front wall 120 of the clamping member 108. As shown in Figure 6c, the chamber 112 is bounded by the curved inner surface of the stationary' member 110, the top of the projection 128 of tire stationary member 110 and the inner surface of the front wall 120 of the clamping member 108. A plurality of apertures 130 (only some of which are labelled) are provided in the back wall 124 of the clamping member 108. In the illustrated example there is a grid of many apertures 130. However, the number of apertures is not critical and there could be one or more apertures 130. The apertures 130 provide an air flow leak path to the outside of the jaws 104 for air entering the chamber 112. This means when air is jetted into the chamber 112, there will not be a build-up of pressure against the back wall 124 of the clamping member 108, which could have the effect of maintaining the clamping member 108 in an unclamped position. Instead, air entering the chamber 112 will result in a force against the inner surface of the front wall 120 of tire clamping member 108. The leak path being in the back wall 124 also means that any escaping air (caused e.g. by air leaks as the clamping member 108 is moved to its clamping position, or while the clamping member 108 is in its clamping position) will leave the jaws 104 outside the clamping area 106 and will not interfere with hair styling. In other examples, not shown in the accompanying Figures, a comparable air flow leak path to the outside of the jaws 104 may be provided by a different means than the exemplified apertures 130, for example as one or more apertures located near to the lower or upper edges of the clamping members 108. An additional advantage of having the back wall 124 surrounding the stationary member, is that it allows a user to apply additional clamping pressure to the clamping members 108 by pushing the back wall 124. Therefore, a user wishing to apply additional clamping pressure can do so by squeezing the outside of the jaws 104. As with previous embodiments described above, tire front wall 120 of each clamping member 108 comprises a passage 132 that connects the chamber 112 to the clamping space 106. In use, air is delivered from the chambers 112 to the clamping space 106 via the respective passages 132. In this embodiment each passage 132 extends along substantially the entire length of the front wall 120 and, more specifically, the upper edge of the front wall 120, when considered in the orientation of the drawings. Moreover, each passage 132 may extend along substantially the length of the clamping space 106. The passage 132 terminates at an airflow outlet 134. As shown, the airflow outlet 134 is provided between the upper edge of the front wall 120 of tire clamping member 108 and the upper end of the outer wall 124 of the clamping member 108. The arrangement and number of passages 132 could of course differ in other examples, however, and the accessory is not intended to be limited in this regard. For example, each clamping member 108 may include multiple passages 132 terminating in multiple airflow outlets 134 extending generally across the entire length of the front wall 120. It would also be possible for the number of passages 132 to differ from the number of airflow outlets 134 such that, for example, multiple passages 132 terminate in a single airflow outlet 134, or a single passage 132 terminates in multiple airflow outlets 134. The arrangement of passages 132 and outlets may differ for each clamping member 108. Although the stationary members 110 have been described as being stationary, they may not always be rigidly fixed in place in relation to the entire device. For example, stationary members 110 may be movable relative to the body 102 to allow adjustment of the size of the clamping space 106. In common with the hair styling device 10 illustrated in Figures 1 to 5. tire hair styling device 100 of Figures 6a to 7c incorporates a feature to provide resistance to the flow of air between airflow inlet and airflow outlet such that, in use, the noise emitted from the hair styling device 100 is reduced whilst pressure is retained within the internal chambers 112 to ensure that the jaws 104 may operate with sufficient clamping force. In the same way as in the previously illustrated example, the hair styling device 100 incorporates a porous structure 160 disposed in an airflow path from the airflow inlet 158 to the airflow outlet 134. The porous structures 160 are configured to allow air to pass therethrough, to the airflow outlet 134, but to retain some pressure within the chamber 112. It will be noted that there are two porous structures 160 provided in this example, one for each of the chambers 112. Therefore, reference will be made to the term ‘porous structure' in the singular, although it should be appreciated that the discussion will relate to both porous structures 160. As in the previously illustrated example, the porous structure 160 includes a porous member 162 and a support 164. The support 164 is in the form of a pair of opposed brackets 165 which are oriented and configured to support each side of the porous member 162. The structure of the support 164 is exemplified by the porous structure 60 shown in Figure 3c and so the associated discussion provided above applies also to the porous structures 60,160 in both illustrated examples. Furthermore, the porous structure 160 is in the form of a mesh as has been discussed so the same characteristics and functional benefits of the porous structure 60 of the previous example also apply here. In Figure 6c, it will be noted that the porous structure 160 is configured such that the pair of support brackets 165 support the porous member 162 so that the porous member 162 extends across the internal chamber 112 between the upper end of the front wall 120 of the clamping member 108 and an upper end of the back wall 124 of the clamping member 108. The porous member 162 is therefore positioned so that airflow from the internal chamber 112 to the passage 132 must pass through the porous member 162. The porous structure 112 can therefore be considered to be positioned between the internal chamber and the airflow outlet 134. Expressed another way, the porous structure 160 is positioned upstream of the airflow outlet 134. Various modifications are envisaged to the illustrated examples that have been described above and which are considered to be encompassed by the inventive concept as defined by the claims. Some variants have already been mentioned. Others will now be discussed briefly. The porous structure 60,160 in the above examples has been discussed as being provided by a planar metallic mesh. However, this is not essential, and other porous structures are considered to be acceptable to achieve the reduction in sound pressure emanating from the hair styling accessory. For example, a porous member formed from a reticulated foam, and optionally a metallic reticulated foam may provide similar functionality, when configured into a form with suitable porosity to provide a comparable flow rate through the porous member but retain sufficient pressure within the internal chambers of the jaws. Furthermore, although it is envisaged in the illustrated examples that the porous structure is in the form of a metallic mesh supported in the internal structure of a respective clamping member, it is further contemplated that a suitable porous structure may be formed in the required position by way of an additive manufacturing process.

Claims

1. A hair styling accessory', comprising:a body supporting a pair of jaws defining a clamping space between them for receiving a tress of hair, at least one of the jaws providing a movable surface configured to releasably clamp the tress of hair between the jaws;wherein at least one of the jaws is provided with an internal chamber configured to receive a flow of air from an airflow inlet, and an airflow outlet; andwherein a porous structure configured to provide resistance to the flow of air is disposed in an airflow path from the airflow inlet to the airflow outlet.

2. The hair styling accessory of Claim 1, wherein the porous structure is disposed at an end of the internal chamber proximal to the airflow outlet.

3. The hair styling accessory of Claims 1 or 2, wherein the airflow outlet is elongate and extends in a direction along an axis, and wherein the porous structure is an elongate structure that extends in a direction aligned with the axis of the airflow outlet.

4. The hair styling accessory of any one of the preceding claims, wherein the porous structure is a substantially planar member.

5. The hair styling accessory of any one of the preceding claims, wherein the porous structure has an open area percentage that is from about 10% to about 40%.

6. The hair styling accessory of any one of the preceding claims, wherein the porous structure is a mesh structure.

7. The hair styling accessory of Claim 6, wherein the mesh structure is a metallic mesh.

8. The hair styling accessory of Claim 7, wherein the metallic mesh is a chemically etchedmetallic mesh.

9. The hair styling accessory of any one of the preceding claims, wherein the jaw having the movable surface further comprises the internal chamber and the airflow outlet.

10. The hair styling accessory of Claim 9, wherein the airflow outlet is provided in the movable5 surface.

11. The hair styling accessory of any one of the preceding claims, wherein the movable surface of the jaw is actuatable by air pressure.10 12. The hair styling accessory of any one of the preceding claims, wherein both jaws of the pairof jaws have a movable surface for clamping a tress of hair between them.19

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