Hairstyling appliance

Abstract

A hairstyling appliance is described. The hairstyling appliance comprises a first arm and a second arm coupled together for reciprocal movement towards and away from each other. The first and second arms are arranged to receive hair within a region therebetween. The hairstyling apparatus comprises a sensor arrangement configured to sense, when the first arm and second arm are brought together to hold hair therebetween, a structural load indicative of a tensile load exerted by the first arm and the second arm on the hair held between the first arm and second arm. In examples, the hairstyling apparatus may comprise an actuator responsive to the sensor arrangement to urge the first arm and the second arm away from each other if the sensed structural load exceeds a threshold value. In other examples, the hairstyling apparatus may comprise a notification module to output a user notification in response to the sensed structural load exceeding a threshold value.

Description

[0001] HAIRSTYLING APPLIANCE

[0002] BACKGROUND

[0003] Hairstyling appliances are designed to use the action of heat, mechanical means and / or airflow to form hair into a desired shape or style.

[0004] A hair straightener can utilise heated plates attached to pivoted arms that can be held, by a user, in a closed configuration with a tress of hair clamped between the heated plates. The tress of hair can be styled into a changed shape once the hair is heated above a transition temperature.

[0005] SUMMARY

[0006] According to a first aspect, there is provided a hairstyling appliance comprising: a first arm and a second arm coupled together for reciprocal movement towards and away from each other, the first arm and the second arm being arranged to receive hair within a region between the first arm and the second arm; a sensor arrangement configured to sense, when the first arm and second arm are brought together to hold hair therebetween, a structural load indicative of a tensile load exerted by the first arm and the second arm on the hair held between the first arm and second arm; and an actuator responsive to the sensor arrangement, wherein the actuator is configured to urge the first arm and the second arm away from each other if the sensed structural load exceeds a threshold value.

[0007] In response to the sensor arrangement in use sensing a structural load indicative of excessive tensile load or strain, the actuator urges apart the arms of the appliance. Thus, grip of the hairstyling appliance on the hair is limited or reduced, thereby limiting or reducing the tensile load on the hair. As such, the hairstyling appliance may improve user comfort and reduce the risk of damage to hair or injury to the user.

[0008] The threshold value may be no less than 2 N and / or no greater than 5 N. Optionally, the threshold value may be around 3 N. As a result, sufficient tension may be applied to the hair to achieve good styling results whilst excessive tension may be avoided that might otherwise cause discomfort or hair damage. The structural load may be a compressive load. More particularly, the sensor arrangement may be configured to sense a compressive load exerted by the first arm and the second arm in a plane parallel to the reciprocal movement of the first arm and the second arm.

[0009] By configuring the sensor arrangement to sense the compressive load exerted by the first arm and the second arm, the sensor arrangement is configured to sense a load indicative of the tensile load applied to the hair when working the hair using the hairstyling appliance.

[0010] The sensor arrangement may be configured to sense the tensile load exerted by the first arm and the second arm in a plane perpendicular to the reciprocal movement of the first arm and the second arm. In particular, the sensor arrangement may be configured to directly sense the tensile load as opposed to, for example, sensing the compressive load indicative of the tensile load.

[0011] The sensor arrangement may comprise a plurality of sensors. Each sensor may be configured to sense a structural load indicative of a tensile load exerted by the first arm and the second arm.

[0012] By using a plurality of sensors, the sensor coverage and sensing accuracy of the sensor arrangement may be improved. For example, utilising a plurality of sensors may be desirable for sensing particular load distributions that may be difficult to sense for a single sensor, such as a non-uniform tensile load.

[0013] The plurality of sensors may comprise a first sensor on the first arm and a second sensor on the second arm. The first sensor and the second sensor may be arranged to oppose each other when the first arm and the second arm are moved towards each other.

[0014] By arranging the first sensor and the second sensor in opposition, sensing accuracy may be improved. The plurality of sensors may comprise a third sensor and a fourth sensor on the first arm.

[0015] The third sensor and the fourth sensor may be spaced apart along the first arm.

[0016] By spacing apart multiple sensors along at least one of the arms, sensor coverage may be improved. Such an arrangement may be particularly suitable for sensing non-uniform load distributions.

[0017] The hairstyling appliance may be configured to output a user notification if the sensed structural load approaches the threshold value. The user notification may comprise at least one of a visual notification, an audible notification or a haptic notification.

[0018] By notifying the user about approaching or exceeding the threshold value, the hairstyling appliance may prompt the user to relax the compressive load exerted by the user compressing the arms of the hairstyling appliance and so reduce the tensile load on the hair. Moreover, this may improve user operation of the hairstyling appliance as the user is guided to avoid unintentionally misusing the hairstyling appliance.

[0019] The hairstyling appliance may be operable in an override mode in which the actuator is prevented from urging the first arm and the second arm apart.

[0020] By providing the override mode, the user may temporarily apply high compressive load or tensile load. In some situations, a high compressive load or a high tensile load exceeding the threshold value may be desired, for example in order to achieve a particular result. As such, the hairstyling appliance may selectively be operable in the override mode.

[0021] The threshold value may be adjustable. An adjustable threshold value may be desirable to accommodate for hair type, desired hair style or hair condition.

[0022] The hairstyling appliance may be configured to directly receive user input for adjusting the threshold value, e.g. using a user interface such as physical or virtual buttons, or the hairstyling appliance may be configured to receive a command adjusting the threshold value from an external device. For example, the hairstyling appliance may be configured to communicate with an external user device and may be configured to receive from the external user device a command instructing the hairstyling appliance to adjust the threshold value.

[0023] The hairstyling appliance may be configured to receive a command from the external user device instructing the hairstyling appliance to set the value of the threshold value based on a user profile. The user profile may include information relating to at least one of hair type, hair condition and desired hair style.

[0024] Utilising user information provided to the external user device may be particularly convenient for adjusting the threshold value by taking into account hair type, desired hair style or hair condition.

[0025] The sensor arrangement may be configured to output a sensor signal indicative of the sensed load. The hairstyling appliance may be configured to transmit the sensor signal to the external user device.

[0026] The external device may forward the sensor signal, for example to an external server, or may locally process the sensor signal and may display the sensor signal to the user.

[0027] The hairstyling appliance may be configured to transmit a command to the external user device to instruct the external user device to output a user notification if the sensed structural load approaches the threshold value. The hairstyling appliance may be configured to transmit the command to exclusively output the user notification via the external user device, e.g. without the hairstyling appliance also outputting a user notification.

[0028] By notifying the user about approaching or exceeding the threshold value, the hairstyling appliance may prompt the user to relax the compressive load exerted by the user compressing the arms of the hairstyling appliance and so reduce the tensile load on the hair. Moreover, this may improve user operation of the hairstyling appliance as the user is guided to avoid unintentionally misusing the hairstyling appliance. According to a second aspect, there is provided a hairstyling system comprising the hairstyling appliance according to the first aspect, and the external user device, wherein: the hairstyling appliance is configured to transmit to the external user device a sensor signal indicative of the sensed structural load or a command if the sensed structural load approaches the threshold value;.

[0029] The external user device may be configured to send to the hairstyling appliance a command instructing the hairstyling appliance to adjust the threshold value.

[0030] According to a third aspect, there is provided a hairstyling appliance comprising: a first arm and a second arm coupled together for reciprocal movement towards and away from each other, the first arm and the second arm being arranged to receive hair within a region between the first arm and the second arm; a sensor arrangement to sense a structural load indicative of a tensile load exerted by the first arm and the second arm; a notification module configured to output a user notification in response to the sensed structural load exceeding a threshold value; wherein the user notification includes at least one of a visual notification, an audible notification or a haptic notification.

[0031] By notifying the user about approaching or exceeding the threshold value, the hairstyling appliance may prompt the user to relax the compressive load exerted by the user compressing the arms of the hairstyling appliance and so reduce the tensile load on the hair. Moreover, this may improve user operation of the hairstyling appliance as the user is guided to avoid unintentionally misusing the hairstyling appliance.

[0032] Features described with reference to the hairstyling appliance according to the first aspect are also applicable to the hairstyling appliance according to the third aspect.

[0033] The external user device may be configured to output a further user notification, based on the sensor signal or the command, if the sensed structural load approaches the threshold value. According to a fourth aspect, there is provided a hairstyling system including the hairstyling appliance according to the third aspect, and further comprising an external user device configured to output the user notification.

[0034] BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 is a schematic cross-sectional view of a hairstyling appliance in an open configuration.

[0036] Figure 2 is a schematic cross-sectional view of the hairstyling appliance of Figure 1 in a closed configuration.

[0037] Figure 3 is a schematic cross-sectional view of arms of the hairstyling appliance of Figure 1, illustrating a first example of sensors in a first configuration.

[0038] Figure 4 is another schematic cross-sectional view illustrating the first example of the sensors, in a second configuration.

[0039] Figure 5 is a schematic cross-sectional view of arms of the hairstyling appliance of Figure 1, illustrating a second example of sensors in a first configuration.

[0040] Figure 6 is another schematic cross-sectional view illustrating the second example of the sensors, in a second configuration.

[0041] Figure 7 is a schematic cross-sectional view of arms of the hairstyling appliance of Figure 1, illustrating a third example of sensors.

[0042] Figure 8 is a schematic cross-sectional view of another hairstyling appliance in a closed configuration.

[0043] Figure 9 is a schematic cross-sectional view of the hairstyling appliance of Figure 8 in the closed configuration, with the arms urged apart.

[0044] Figure 10 is a schematic cross-sectional view of another hairstyling appliance in an open configuration.

[0045] Figure 11 is a schematic cross-sectional view of the hairstyling appliance of Figure 10 in a closed configuration, with the arms urged apart.

[0046] Figure 12 is a schematic plan view of the second arm of the hairstyling appliance of Figure 10.

[0047] Figure 13 is a schematic illustration of a hairstyling system including the hairstyling appliance according to Figure 1. DETAILED DESCRIPTION

[0048] When working hair with a hairstyling appliance, such as a hair straightener, strain is caused on the user’s hair. When too much force is applied whilst straightening, hair damage can occur. For example, hair could become more unruly, could be pulled out of the scalp, or could experience excessive surface heat loading. The hairstyling appliances described herein may improve user comfort, may reduce the risk of damage to hair, and / or may reduce the risk of injury to the user.

[0049] Figures 1 and 2 are schematic cross-sectional views of a hairstyling appliance 10. Figure 1 shows the hairstyling appliance 10 in an open configuration, while Figure 2 shows the hairstyling appliance 10 in a closed configuration.

[0050] The hairstyling appliance 10 comprises a first arm 12 and a second arm 14 coupled together for reciprocal movement towards and away from each other. The reciprocal movement takes place in a plane coinciding with the plane of the cross-sectional views of Figure 1 and 2. In the illustrated example, the first arm 12 and the second arm 14 are joined at a pivot joint 16 about which the first arm 12 and the second arm 14 are pivotable to enable the reciprocal movement.

[0051] The first arm 12 and the second arm 14 are biased by springs (not shown) towards the open configuration and can be manually brought into the closed configuration against the bias of the springs by a user.

[0052] Each arm 12, 14 terminates at a tip region 17. In this example, the tip region 17 is distal to the pivot joint 16. In some examples, the tip region 17 may be distal to, e.g., an extended handle section (not shown) of the hairstyling appliance 10.

[0053] Each arm 12, 14 includes a leading edge 18 and a trailing edge 19 (see, for example, Figures 3 and 4).

[0054] The first arm 12 and the second arm 14 are arranged to receive hair within a region in the form of drying cavity 20. The drying cavity 20 is a space between the first arm 12 and the second arm 14 within which a hair tress 22 is captured when the hairstyling appliance 10 is in use. The leading edge 18 and the trailing edge 19 bound the drying cavity 20 in a direction perpendicular to the plane in which the reciprocal movement of the arms 12, 13 takes place.

[0055] In use, while the hairstyling appliance 10 is in the open position, a user places the hair tress 22 within drying cavity 20 between first arm 12 and the second arm 14. Typically, the hairstyling appliance 10 is positioned close to the user’s scalp but other positions may be selected depended upon the desired styling effect. The user then squeezes the first arm 12 and the second arms 14 together towards the closed configuration, thereby gripping the hair tress 22 within the drying cavity 20. While the user draws the hairstyling appliance 10 away from the scalp, heat generated by the hairstyling appliance 10 dries the hair tress 22 within the drying cavity 20, straightening and smoothing the hair tress 22, as hair enters the drying cavity 20 crossing the leading edge 18 and leaves the drying cavity 20 crossing the trailing edge 19.

[0056] Working the hair tress by pulling hair through the drying cavity 20 causes a tensile load on the hair tress 22. Conveniently, the hairstyling appliance 10 is configured to assist the user in avoiding excessive tensile load by taking action to reduce the tensile load, as described with reference to Figures 1, 2, 8, 9, 10, 11; or by alerting the user such that the user may take action, as described with reference to Figure 12. In some examples, the hairstyling appliance 10 may both alert the user and take action to reduce the tensile load.

[0057] Suitably, the hairstyling appliance 10 includes a sensor arrangement 30 to sense a structural load indicative of the tensile load exerted by the hairstyling appliance 10 on the hair tress 22. The sensor arrangement 30 may sense the tensile load directly, as described with reference to Figures 3 to 6, 10 and 11. Additionally or alternatively, the sensor arrangement 30 may sense a related parameter, e.g. a compressive load, based on which the tensile load may be estimated; as described with reference to Figure 7.

[0058] The sensor arrangement 30, which in this example comprises a first sensor 32 and a second sensor 34, is configured to sense a structural load indicative of the tensile load exerted by the hairstyling appliance 10 on the hair tress 22. Conveniently, the sensor arrangement is exposed in the drying cavity 20 and in use contacts the hair tress 22, e.g. as illustrated for the first sensor 32 and the second sensor 34 in Figure 2.

[0059] The first sensor 32 is provided on the first arm 12 and the second sensor 34 is provided on the second arm 14. More particularly, the first sensor 32 and the second sensor 34 are arranged along the arms 12, 14 such that the first sensor 32 and the second sensor 34 oppose each other when the arms 12, 14 are moved towards each other.

[0060] The hairstyling appliance 10 includes an actuator 40. The actuator 40 is responsive to the sensor arrangement 30 and is configured to urge the first arm 12 and the second arm 14 away from each other if the sensed or estimated tensile load exceeds a threshold value. The threshold value may be no less than 2 Newtons and / or no greater than 5 Newtons. A threshold value less than 2 Newtons may be insufficient to achieve desired styling results, while a threshold value exceeding 5 Newtons may lead to discomfort and / or could potentially damage the hair. A threshold value of around 3 Newtons may provide a good balance between these factors for most hair types.

[0061] It is noted that urging apart of the arms 12, 14 by the actuator 40 need not increase the separation between the arms 12, 14. For example, the user’s compressive force exerted on the arms 12, 14 and the urging apart of the arms 12, 14 may in effect cancel each other such that the separation of the arms 12, 14 remains substantially unchanged. As such, the hairstyling appliance 10 would resist further compression by the actuator 40 urging apart the arms 12, 14.

[0062] By urging apart the first arm 12 and the second arm 14, grip of the hairstyling appliance 10 on the hair tress 22 is in use limited or reduced and so the exerted tensile load is also limited or reduced. As such, the risk of damage to hair or injury to the user may be reduced and user comfort may be increased.

[0063] In this example, the actuator 40 is a motor, such as a brushless DC motor, such as a gimbal motor, located in the pivot joint 16 and configured to actuate the pivot joint 16 to urge apart the first arm 12 and the second arm 14 in response to the structural load sensed by the sensor arrangement 30 exceeding the threshold value. More generally, any actuator may be used, such as a stepper-driven lead screw, and further examples are described with reference to Figures 8 to 12.

[0064] The hairstyling appliance 10 includes a controller 50 configured to receive a sensor signal from the sensor arrangement 30. The sensor signal is representative of the sensed structural load, and in some examples corresponds to the output of the sensors 32, 34. The controller 50 is configured to compare the sensed structural load against the threshold value and, if the threshold value is exceeded, control the actuator 40 to urge apart the first arm 12 and the second arm 14.

[0065] Figures 3, 4, 5 and 6 are cross-sectional views through both arms 12, 13 of the hairstyling appliance 10, wherein the cross-section corresponds to a plane perpendicular to the plane of the reciprocal movement of the arms 12, 13, and illustrate example sensors of the sensor arrangement 30. More particularly, Figures 3 and 4 illustrate a first example, while Figures 5 and 6 illustrate a second example.

[0066] According to Figures 3 to 6, each sensor 32, 34 comprises a contact member 35 and a biasing member 36. The contact member 35 is arranged to contact the hair tress 22 and, when the hairstyling appliance 10 in use exerts a tensile load on the hair tress 22, is displaced from a resting position towards the trailing edge 19 to a deflected position. The rest position is illustrated in Figures 3 and 5, while the deflected position is illustrated in Figures 4 and 6. The biasing member 36 is provided to exert a restoring force on the contact member 35 when displaced from the rest position to urge the contact member 35 towards the rest position. In particular, the biasing member 36 is configured to urge the contact member 35 towards the leading edge 18 when the contact member 35 has been displaced towards the trailing edge 19. In Figures 3 and 4, the biasing member 36 is provided as a torsion spring. In Figures 5 and 6, the biasing member 36 is provided as a compression spring. The displacement of the contact member 36 is related to the tensile load on the hair tress 22. As such, the tensile load may be calculated or estimated based on the displacement of the contact member 35, e.g. by the controller 40, in order to control the actuator 40, or the displacement of the contact member 35 may be used to mechanically control an actuator (as described with reference to Figures 10 to 12).

[0067] Figure 7 illustrates a third example sensor of the sensor arrangement 30. According to Figure 7, the first sensor 32 and the second sensor 34 are configured to sense the compressive load which in use is exerted by the arms 12, 14 on the hair tress 22. Said compressive load is in a plane perpendicular to the hair tress 22 extending through the drying cavity 20. Suitably, the sensors 32, 34 include compression load sensors 37, e.g. piezoelectric sensors, configured to sense the compressive load exerted by the user when urging the arms 12, 14 together and gripping the hair tress 22. The compressive load so exerted by the hairstyling appliance 10 on the hair tress 22 may be used to calculate or approximate the tensile load on the hair tress 22.

[0068] According to Figure 7, each sensor 32, 34 includes the contact member 35 and the forcesensitive element 37. In some examples, the compression load sensors 37 are exposed to the hair tress 22.

[0069] Figures 8 and 9 are schematic cross-sectional views of the hairstyling appliance 10 illustrating another example actuator 42. Figures 8 and 9 both show the hairstyling appliance 10 in the closed configuration with the hair tress 22 gripped between the arms 12, 14 of the hairstyling appliance 10. In Figure 9, the actuator 42 urges apart the arms 12, 14 to reduce the tensile load on the hair tress 22.

[0070] According to Figures 8 and 9, the actuator 42 is provided as a piston on the second arm 14. The piston is extendible from the second arm 14 to engage the first arm 12 and to thereby urge apart the arms 12, 14. The piston is shown in a retracted configuration in Figure 8, and in an extended configuration in Figure 9. In Figures 8 and 9, a notification module 60 of the hairstyling appliance 10 is illustrated. The notification module 60 is configured to output a user notification to the user. The controller 50 is configured to control the notification module 60 to output the user notification if the sensed structural load approaches or exceeds the threshold value. The notification module 60 may be configured to output a visual notification, an audible notification or a haptic notification, e.g. a vibration. In this example, the notification module 60 is provided as a loudspeaker configured to output an audible notification to the user in order to alert the user about approaching or exceeding the threshold value.

[0071] In Figures 8 and 9, multiple sensors 34 are provided along the second arm 14 of the hairstyling appliance 10. The sensors 34 on the second arm 14 are spaced along the second arm 34 extend sensor coverage along the second arm 14. That is to say, a distance to the tip region 17 is greater for one of the sensors 34, and smaller for the other of the sensors 34. More generally, each arm 12, 14 may be provided with any number of sensors.

[0072] The hairstyling appliance 10 operable in an override mode in which the actuator 42 is prevented from urging the first arm 12 and the second arm 14 apart. By providing the override mode, the user may temporarily apply high compressive load or tensile load. In some situations, a high compressive load or a high tensile load exceeding the threshold value may be desired, for example in order to achieve a particular result. As such, the override mode is user selectable, for example by holding a button on the hairstyling appliance 10 depressed, to operate the hairstyling appliance 10 without the arms 12, 14 being urged apart.

[0073] Figures 10, 11 and 12 illustrate the hairstyling appliance 10 with another example sensor, including a rotatable contact member 38, and another example actuator, provided as an actuator cam 44. Figures 10 and 11 are schematic cross-sectional views of the hairstyling appliance 10, while Figure 12 is a plan view of part of the second arm 14. According to the Figures 10, 11 and 12, the rotatable contact member 38 and the actuator cam 44 are provided as an integrated mechanical system to sense the structural load and to urge apart the arms 12, 14. The rotatable contact member 38 may be provided, for example, as a plate configured to be rotatable (e.g. tiltable or pivotable), or a pin configured to be rotatable. The rotatable contact member 38 extends along the second arm 14. In some examples, the rotatable contact member 38 extends across the entire second arm 14, i.e. from the joint 16 to the tip region 17. In the present example, the rotatable contact member 38 extends along part of the second arm 14.

[0074] The rotatable contact member 38 and the actuator cam 44 are jointly rotatable about a common rotation axis 45 between a first configuration in which the actuator cam 44 is retracted and a second configuration in which the actuator cam 44 is extended towards the first arm 12. The rotatable contact member 38 and the actuator cam 44 are biased towards the first configuration in which the actuator cam 44 is retracted, for example by a suitable biasing member such as torsion spring (not shown).

[0075] In use, the rotatable contact member 38 engages the hair tress 22 and, when working the hair tress 22, the rotatable contact member 38 is caused to rotate in response to tensile load exerted on the hair tress 22. The rotation of the rotatable contact member 38 causes the actuator cam 44 to rotate likewise, thereby rotating and extending the actuator cam 44. This causes the actuator cam 44 to engage and lift the first arm 12, i.e. to urge apart the first arm 12 and the second arm 14.

[0076] As such, the hair styling appliance 10 utilising the rotatable contact member 38 and the actuator cam 44 provides a mechanical system for sensing the structural load indicative of the tensile load on the hair tress 22, and for urging apart the arms 12, 14 to reduce the tensile load. Alternatively, the actuator cam 44 could be rotated using a suitable motor in response to a sensor signal from an electronic sensor, such as a piezoelectric or resistive element. Equally, the rotatable contact member 38 could be used with the controller 50, for example by suitably measuring rotation or deflection / tilt of the rotatable contact member 38, such as deflection in an electric field or sliding contact with a resistive track to provide variable electrical resistance dependent on the deflection or rotation. Figure 13 illustrates a hairstyling system 100 including the hairstyling appliance 10 and an external user device 90. The user device 90 may be any user device for communicating with the hairstyling appliance 10 and the user, such as a mobile phone or a tablet. The hairstyling appliance 10 is configured to communicate with the user device, e.g. through a wired or wireless connection, such as Bluetooth or Wi-Fi. Suitably, the hairstyling appliance 10 comprises a communication module 70 for communicating with the user device 90.

[0077] The user device 90 is configured to output a user notification in response to the sensed structural load approaching the threshold. As such, the hairstyling appliance 10 communicates with the user device 90 using the communication module 70. In some examples, the hairstyling appliance 10 communicates the sensed structural load to the user device 90. In some examples, the hairstyling appliance 10 communicates an alert to the user device 90 when the threshold value is exceeded.

[0078] The user notification may be a visual notification, an audible notification, or both visual and audible notification. For example, a message may be displayed by the user device 90 and a sound may be output by the user device 90 to alert the user. In some examples, the user is informed that the threshold value has been exceeded. In some examples, the user is instructed to reduce the compressive force applied by the user.

[0079] The threshold value is adjustable using the user device 90. In some examples, the threshold value is additionally or alternatively adjustable directly at the hairstyling appliance 10, for example by moving a dial on the hairstyling appliance 10 or using any other suitable input device. In this example, the hairstyling appliance 10 is configured to receive from the user device 90 a command instructing the hairstyling appliance 10 to adjust the threshold value.

[0080] The threshold value is adjustable across a suitable range of threshold values. In some examples, the threshold value is adjustable across a range of threshold values from 2 Newtons to 5 Newtons. In some examples, the command instructing adjustment of the threshold value is based on a user profile stored by the user device 90 or an external server (not shown). The user profile may include information relating to at least one of user hair type (e.g. according to main types 1 to 4 designating straight, wavy, curly and coily, respectively), hair condition (e.g. whether hair is dyed; whether hair is wet) and desired hair style. As such, the threshold value may be adjusted automatically based on the user profile without the user needing to specify a particular adjustment.

[0081] In some examples, the command instructing adjustment of the threshold value is issued by the user directly specifying an adjustment of the threshold value.

[0082] Utilising user information provided to the user device may be particularly convenient for adjusting the threshold value by taking into account hair type, desired hair style or hair condition.

Claims

CLAIMS1. A hairstyling appliance comprising: a first arm and a second arm coupled together for reciprocal movement towards and away from each other, the first arm and the second arm being arranged to receive hair within a region between the first arm and the second arm; a sensor arrangement configured to sense, when the first arm and second arm are brought together to hold hair therebetween, a structural load indicative of a tensile load exerted by the first arm and the second arm on the hair held between the first arm and second arm; and an actuator responsive to the sensor arrangement, wherein the actuator is configured to urge the first arm and the second arm away from each other if the sensed structural load exceeds a threshold value.

2. The hairstyling appliance according to claim 1, wherein the sensor arrangement is configured to sense a compressive load exerted by the first arm and the second arm in a plane parallel to the reciprocal movement of the first arm and the second arm.

3. The hairstyling appliance according to claim 1, wherein the sensor arrangement is configured to sense the tensile load exerted by the first arm and the second arm in a plane perpendicular to the reciprocal movement of the first arm and the second arm.

4. The hairstyling appliance according to any preceding claim, wherein the sensor arrangement comprises a plurality of sensors, each sensor configured to sense a structural load indicative of a tensile load exerted by the first arm and the second arm.

5. The hairstyling appliance according to claim 4, wherein the plurality of sensors comprises a first sensor on the first arm and a second sensor on the second arm, and the first sensor and the second sensor are arranged along the first arm and the second arm to oppose each other when the first arm and the second arm are moved towards each other.

6. The hairstyling appliance according to claim 4 or 5, wherein the plurality of sensors comprises a third sensor and a fourth sensor on the first arm, and the third sensor and the fourth sensor are spaced apart along the first arm.

7. The hairstyling appliance according to any preceding claim, wherein the hairstyling appliance is configured to output a user notification if the sensed structural load approaches the threshold value, and wherein optionally the user notification comprises at least one of a visual, an audible or a haptic notification.

8. The hairstyling appliance according to any preceding claim, wherein the hairstyling appliance is operable in an override mode in which the actuator is prevented from urging the first arm and the second arm apart.

9. The hairstyling appliance according to any preceding claim, wherein the threshold value is adjustable.

10. The hairstyling appliance according to claim 9, wherein the hairstyling appliance is configured to communicate with an external user device and is configured to receive from the external user device a command instructing the hairstyling appliance to adjust the threshold value.

11. The hairstyling appliance according to claim 10, wherein the hairstyling appliance is configured to receive a command from the external user device instructing the hairstyling appliance to set the value of the threshold value based on a user profile, and the user profile includes information relating to at least one of user hair type, hair condition and desired hair style.

12. The hairstyling appliance according to any preceding claim, wherein the sensor arrangement is configured to output a sensor signal indicative of the sensed load; and the hairstyling appliance is configured to transmit the sensor signal to an external user device.

13. The hairstyling appliance according to any preceding claim, wherein the hairstyling appliance is configured to transmit a command to an external user device to instruct the external user device to output a user notification if the sensed structural load approaches the threshold value.

14. A hairstyling appliance comprising: a first arm and a second arm coupled together for reciprocal movement towards and away from each other, the first arm and the second arm being arranged to receive hair within a region between the first arm and the second arm; a sensor arrangement to sense a structural load indicative of a tensile load exerted by the first arm and the second arm; and a notification module configured to output a user notification in response to the sensed structural load exceeding a threshold value, wherein the user notification includes at least one of a visual, an audible or a haptic notification.

15. A hairstyling system comprising the hairstyling appliance according to claim 14 and an external user device, wherein: the hairstyling appliance is configured to transmit to the external user device a sensor signal indicative of the sensed structural load or a command if the sensed structural load approaches the threshold value; and the external user device is configured to output a further user notification, based on the sensor signal or the command, if the sensed structural load approaches the threshold value.

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