An appliance

Abstract

An appliance includes an electric motor, a magnet 104 , and a sensor 106 configured to sense a direction of a magnetic field produced by the magnet. The appliance includes a controller configured to e

Description

B ACKGROUND Appliances may comprise electric motors that are utilised to generate airflows through the appliance. It may be desirable to control airflow through the appliance when certain functionality of the appliance is required. SUMMARY According to a first aspect of the present invention there is provided an appliance comprising: an electric motor; a magnet; a sensor configured to sense a direction of a magnetic field produced by the magnet; and a controller configured to enable operation of the appliance with the electric motor at a first motor speed in response to a first direction of magnetic field sensed by the senor, and to enable operation of the appliance with the electric motor at a second motor speed in response to a second direction of magnetic field sensed by the sensor, the second direction of magnetic field different to the first direction of the magnetic field, and the second motor speed lower than the first motor speed. Appliances in which operation of an electric motor is controlled based on a sensed magnitude of magnetic flux have previously been proposed. Such appliances typically utilise sensors to monitor a magnitude of magnetic flux from a magnet, and when there is relative movement between the sensor and the magnet, for example as a result of a user moving an actuator such as a lever or the like, the monitored magnitude of magnetic flux changes. The electric motor is then controlled based on the monitored magnitude of magnetic flux. In some instances, it may be desirable to change operation of the electric motor in response to relatively small movements of an actuator by a user. However, it has been found that tolerance stacks in manufacture and / or operation of components of such appliances, where the magnitude of magnetic flux is used as a control factor, can result in relatively narrow movement windows leading to change in operation of the electric motor. This may be undesirable, as such small motions can occur accidentally during use of the appliance. By enabling operation of the appliance with the electric motor at different motor speeds depending on which direction of magnetic field is sensed by the sensor, the appliance according to the first aspect of the invention has been found to provide an increased size of movement window relative to arrangements that utilise sensed magnitude of magnetic flux as a control factor. This may lead to a reduced risk of accidental change in operation of the electric motor in use, and can provide an improved user experience for a user of the appliance. The magnet may comprise a two-pole magnet, for example comprising a single north pole and a single south pole. This may enable use of a relatively simple and / or inexpensive magnet. The magnet may comprise a bar magnet. The sensor may comprise a Hall effect sensor. The sensor may comprise a linear Hall effect sensor. Use of a linear Hall effect sensor compared to, for example, use of a digital output Hall effect sensor, may provide control over thresholds at which switching of enablement of the electric motor to operate at the first and second motor speeds occurs. The sensor may be configured to sense a magnitude of magnetic flux produced by the magnet. The magnet may be separate from the electric motor, for example separate from any magnet of the electric motor. The sensor may be separate from the electric motor, for example separate from any sensor of the electric motor. The electric motor may comprise an impeller that generates airflow through the appliance. The second motor speed may be zero. This may enable operation of the appliance in a state in which the electric motor is turned off, for example in response to relative displacement between the magnet and the sensor, which may be desirable to allow for certain functionality of the appliance to take place. The controller may be configured to disable provision of power to the electric motor from a power supply in response to the second direction of magnetic field sensed by the sensor. This may ensure that, whilst the second direction of magnetic field is sensed by the sensor, operation of the electric motor is inhibited, even if a user attempts to do so. This may inhibit enable operation of the appliance with the electric motor running when certain functionality of the appliance is desired and / or performed, for example with such functionality occurring in response to operation of an actuator by a user of the appliance that causes the second direction of magnetic field to be sensed by the sensor. The controller may control a switch electrically located between the electric motor and the power supply based on whether the first or second direction of magnetic field is sensed by the sensor. The controller may be configured to enable provision of power to the electric motor from the power supply in response to the first direction of magnetic field sensed by the sensor. The appliance may comprise the power supply, for example with the power supply being a battery. This may enable the appliance to be utilised absent a connection to a mains power supply. The appliance may be configured to enable relative movement between the magnet and the sensor. Such relative movement may result in the direction of the magnetic field sensed by the sensor switching from the first direction to the second direction, and use of movement to trigger the change in sensed field direction may provide a relatively simple and / or inexpensive control mechanism in comparison to a driven electromagnet, for example. The appliance may comprise a movable member. The magnet may be fixedly attached to the movable member such that movement of the movable member moves the magnet relative to the sensor. Fixedly attaching the magnet to the movable member may provide a relatively simple arrangement compared to, for example, fixedly attaching the sensor to the movable member. In particular, if the sensor were mounted to the movable member, then electrical connections to and / or from the sensor would need to be taken into account during movement of the movable member. The movable member may be movable between a first position at which the magnet is located at a first magnet position relative to the sensor such that the sensor senses the first direction of magnetic field, and a second position at which the magnet is located at a second magnet position relative to the sensor such that the sensor senses the second direction of magnetic field. The first position may comprise a default position at which the movable member is intended to be located when the appliance is operated in a primary operating state with the electric motor switched on. The second position may be a position at which the user places the movable member to begin operation of the appliance in a secondary operating state with the electric motor switched off. The second position may be spaced from the first position by no more than 15mm, for example no more than 10mm. The movable member may be operable by a user whilst the electric motor is operating at the first motor speed, for example such that the movable member can cause operation of the electric motor to switch from the first motor speed to the second motor speed in response to the movable member moving from the first position to the second position. The appliance may comprise a user operable actuator configured to cause provision of a control signal to control the electric motor to operate in one of an on state and an off state. The user operable actuator may be separate to the movable member. In such a manner a user may indicate their desire for the electric motor to be turned on by using the user operable actuator, but if they have also moved the movable member to the second position, then the controller has disabled provision of power to the electric motor from a power supply. This may inhibit a user from attempting to utilise the electric motor in conjunction with functionality, indicated by movement of the movable member to the second position, with which operation of the electric motor is not intended. The appliance may be a vacuum cleaner. The appliance may comprise a bin for collecting dust; a body movable within the bin to interact with dust collected in the bin; and a closure that selectively closes the bin. The controller may be configured to enable operation of the appliance with the electric motor at the second motor speed when at least one of the body moves within the bin, and the closure is opened to open the bin. This may provide a reduced speed, or indeed zero speed, of the electric motor when at least one of the body moves within the bin, and the closure is opened to open the bin. This may reduce and / or inhibit suction power being provided whilst a user is trying to interact with dust collected in the bin. The movable member may be configured to cause movement at least one of the body and the closure in response to movement of the movable member by a user of the appliance, and one of the magnet and the sensor may be fixedly attached to the movable member. The movable member may thereby provide dual functionality in that it can cause, by virtue of its movement, both enabling operation of the appliance with the electric motor at the first and second motor speeds, and movement at least one of the body and the closure. The other of the sensor and the magnet may be fixedly attached to a part of the appliance relative to which the movable member moves. The magnet may be fixedly attached to the movable member. Where the movable member is configured to cause movement of the body, the magnet may be fixedly attached to the movable member, the movable member may be movable in a first direction orthogonal to a second direction in which the body moves within the bin, and movement of the movable member in the first direction may move the magnet relative to the sensor. By moving the movable member in the first direction, a transition of operation of the electric motor from the first motor speed to the second motor speed may occur prior to the body moving in the second direction. Furthermore, a relatively large amount of movement may be required for movement of the body within the bin in the second direction. By moving the movable member in the first direction to move the magnet, a transition between enabling operation of the appliance with the electric motor at the first and second motor speeds may be affected with a smaller degree of movement than is required for moving the body within the bin. The movable member may be movable in the second direction, for example subsequently to moving in the first direction. In such a manner the movable member may be utilised to firstly transition the appliance from a state in which operation of the appliance with the electric motor is enabled at the first motor speed to a state in which operation of the appliance with the electric motor is enabled at the second motor speed, before subsequently being used to move the body within the bin. The movable member may be pivotable in the first direction. The movable member may be slidable in a direction parallel to the second direction. The movable member may be rigidly connected the body, for example such that sliding motion of the movable member causes sliding motion of the body within the bin. The sensor may comprise a sensor face oriented in a plane having a first axis parallel to the first direction and a second axis orthogonal to the first direction and the second direction, and the magnet may be oriented such that a north-south axis of the magnet is substantially parallel to the second direction. This may provide a wider movement window, when accounting for tolerances, between states in which operation of the electric motor at the first and second motor speeds is enabled, compared to an arrangement in which the magnet is oriented such that the north-south axis of the magnet is substantially parallel to the first direction. The sensor may comprise a sensor face oriented in a plane having a first axis parallel to the first direction and a second axis orthogonal to the first direction and the second direction, and the magnet may be oriented such that a north-south axis of the magnet is substantially parallel to the first direction. The appliance may comprise a compaction mechanism for compacting dust collected within the bin, and the body may define a compaction plate of the compaction mechanism. It may be desirable for compaction of dust collected within the bin to occur when relatively little or no suction is applied to collect dust within the bin. The above described mechanisms may facilitate this. The appliance may comprise a bin wiping mechanism for wiping dust from at least one of an internal surface of the bin and surfaces of components contained within the bin, and the body may define a wiping member of the bin wiping mechanism. It may be desirable for wiping of dust collected within the bin to occur when relatively little or no suction is applied to collect dust within the bin. The above described mechanisms may facilitate this. The appliance may comprise a closure opening mechanism, and movement of the movable member in the second direction may cause actuation of the closure opening mechanism to open the closure relative to the bin. The closure opening mechanism may comprise a push rod rigidly connected to the movable member, the push rod configured to release a closure mechanism that holds the closure relative to the bin in response to movement of the push rod in the second direction. The appliance may comprise a removable filter, and movement of the filter to remove the filter from a main body of the appliance may cause a direction of the magnetic field sensed by the sensor to change. In such a manner operation of the electric motor at the second motor speed may be enabled in response to movement of the filter to remove the filter from a main body of the appliance. This may, for example, enable operation of the electric motor at a reduced speed, or indeed disable the electric motor, in response to movement of the filter to remove the filter from a main body of the appliance. This may ensure that the appliance cannot be operated with full functionality in the event that the filter is removed from the appliance. The filter may be configured to filter airflow pre and / or post the electric motor. BRIEF DESCRIPTION OF THE DRAWINGS Figure lisa schematic view of a first embodiment of an appliance; Figure 2 is a schematic view of a main unit of the appliance of Figure 1; Figure 3 is an exploded view of a compaction assembly of the main unit of Figure 2; Figure 4 is an assembled view of the compaction assembly of Figure 3; Figure 5 is an exploded view of a compaction plate sub-assembly of the compaction assembly of Figure 3; Figure 6 is a schematic view of a compaction handle of the compaction assembly of Figure 3 in a default position; Figure 7 is a schematic view of a compaction handle of the compaction assembly of Figure 3 in a pivoted position; Figure 8 is a graph illustrating a movement window associated with a prior art sensor assembly; Figure 9 is a graph illustrating a movement window associated with a sensor assembly of the compaction assembly of Figure 3; Figure 10 is a schematic view of an alternative compaction handle of an alternative compaction assembly in a default position; Figure 11 is a schematic view of the alternative compaction handle of Figure 10 in a pivoted position; Figure 12 is a graph illustrating a movement window associated with a sensor assembly of the compaction assembly of Figures 10 and 11; Figure 13 is a schematic view of a second embodiment of an appliance; Figure 14 is an assembled view of a compaction assembly of the appliance of Figure 13; Figure 15 is a schematic view of a compaction handle of the compaction assembly of Figure 14 in a default position; Figure 16 is a schematic view of a compaction handle of the compaction assembly of Figure 14 in a pivoted position; Figure 17 is a graph illustrating a movement window associated with a sensor assembly of the compaction assembly of Figure 14; Figure 18 is a schematic illustration of a closure opening mechanism for use with an appliance; Figure 19 is a schematic illustration of a filter assembly for use with an appliance; and Figure 20 is a schematic illustration of a further filter assembly for use with an appliance. DETAILED DESCRIPTION A first embodiment of an appliance 10 is illustrated schematically in Figure 1. The appliance 10 comprises a main unit 12, a wand 14, and a cleanerhead 16. The appliance 10 is a so-called “handheld” vacuum cleaner, with the user able and intended to support the main unit 12 in their hand in use, and is battery-powered. Details of the wand 14 and the cleanerhead 16 are not pertinent to the present invention, and so the wand 14 and the cleanerhead 16 will not be described in further detail for sake of brevity. The main unit 12 is illustrated in isolation in Figure 2, and comprises a bin assembly 18, a primary separation system 20, a compaction mechanism 22, a secondary separation system 24, a motor assembly 26, a housing portion 28, a handle portion 30, and a battery assembly 32. The bin assembly 18 comprises a bin 34 and a closure 36 hingedly mounted to the bin 34. The bin 34 has an interior volume that acts as a debris collection chamber 37 in use. The closure 36 has a spigot 38 that defines an air inlet 40 into the bin 34. The primary separation system 20 is disposed within the interior volume of the bin 34, and comprises a U-shaped core 42, and a mesh 44 disposed on the U-shaped core 42. The U-shaped core 42 is generally hollow in form, and defines an airflow passageway 46 from the bin 34 to the secondary separation system 24. The U-shaped core 42 is wrapped around a central longitudinal axis CL of the main unit 12. The mesh 44 comprises a plurality of apertures, and acts to filter debris from airflow through the main unit 12 in use, as will be described in more detail hereinafter. The compaction mechanism 22 is illustrated in isolation in Figures 3 to 7. The compaction mechanism 22 comprises a compaction plate sub-assembly 48, a core wiping member 50 (which may be considered to be a filter wiping member), a bin wiping member 52, first 54 and second 56 compaction rods, and a compaction handle assembly 58. The compaction mechanism 22 or various components thereof may be considered to form a wiping mechanism, which in this case is configured to wipe both a wall of the bin 34 and the mesh 44 in a single actuation of the wiping mechanism. It is to be appreciated, though, that in other examples there may be a separate compaction mechanism 22 and wiping mechanism. The compaction plate sub-assembly 48 comprises a front plate 60, a middle plate 62, and a rear plate 64. Collectively the front plate 60, the middle plate 62, and the rear plate 64 can be thought of as a body movable within the bin 34, as will be described in further detail hereinafter. The front plate 60 comprises a compaction body 66, a front plate through-hole 68, and a front flange 70. The compaction body 66 is generally circular in form, and defines a generally flat compaction surface. The front plate through-hole 68 is generally U-shaped in form, and is shaped and dimensioned to slidably receive the U-shaped core 42. The front plate through-hole 68 is formed in the compaction body 66. The front flange 70 is generally U-shaped in form, and curves about a base of the generally U-shaped front plate through-hole 68. The front flange 70 extends from the compaction body 66 such that the front flange 70 is located on an opposite side of the compaction plate sub-assembly 48 to the first 54 and second 56 compaction rods. The middle plate 62 is generally U-shaped in form, and is located on an opposite side of the compaction body 66 to the front flange 70. The rear plate 64 has substantially the same form as the front plate 60 save for the front flange 70, and further includes rod receiving apertures shaped and dimensioned to receive a corresponding one of the first 54 and second 56 compaction rods. The rear plate 64 is located on an opposite side of the middle plate 62 to the front plate 60. The core wiping member 50 is generally U-shaped in form, and is shaped and dimensioned to correspond to a periphery of the front plate through-hole 68, and to correspond to a periphery of the U-shaped core 42. The core wiping member 50 is formed of a resiliently deformable material, and is mounted to the front plate 60 about the periphery of the front plate through-hole 68 such that a periphery of the core wiping member 50 is angled toward the front plate through-hole 68. The bin wiping member 52 is generally annular in form, and is shaped and dimensioned to correspond to an outer periphery of the front plate 60. The bin wiping member 52 is formed of a resiliently deformable material, and is mounted to the front plate 60 about the periphery of the front plate 60 such that an outer rim of the bin wiping member 306 is angled away from the front plate 60. The first 54 and second 56 compaction rods are each generally cylindrical and elongate in form between a first end and a second end. The first 54 and second 56 compaction rods are slidable within respective tracks (not shown) formed on an inner surface of the bin 34, to enable movement of the compaction plate sub-assembly 48 within the bin 34. The compaction handle assembly 58 comprises a compaction handle 74, first 76 and second 78 compaction handle connectors, and a compaction sensor assembly 80. The compaction handle 74 comprises a handle body 82, and first 84 and second 86 connection portions that are upstanding from the handle body 82. The handle body 82 is generally semi-circular in form. The first 84 and second 86 connection portions are located at opposite sides of the handle body 82, and comprise respective first apertures 88 and second apertures 90 that receive respective first projections 92 and second projections 94 formed on the first 76 and second 78 compaction handle connectors. The first apertures 88 and the first projections 92, and the second apertures 90 and the second projections 94 enable pivoting motion of the compaction handle 74 relative to the first 76 and second 78 compaction handle connectors, as will be described in more detail hereinafter. The first apertures 88 have a size substantially corresponding to a size of the first projections 92, whilst the second apertures 90 have a size bigger than a size of the second projections 94, so that the second projections 94 can slide within the second apertures 90. Each of the first 76 and second 78 compaction handle connectors comprises a handle connection portion 96, a main body portion 98, and a rod connection portion 100. The handle connection portions 96 have the respective first 92 and second 94 projections. The main body portions 98 are generally elongate in form, and extend between the respective handle connection portion 96 and the rod connection portion 100. The rod connection portions 100 are upstanding from the main body portion 98, and comprise through-holes shaped and dimensioned to receive the respective first 54 and second 56 compaction rods. The compaction sensor assembly 80 is illustrated in Figures 6 and 7, and comprises a magnet 104 and a Hall effect sensor 106. The magnet 104 is a bar magnet, having a north pole 108 and a south pole 110. The magnet 104 is coupled to the first connection portion 84 of the compaction handle 74, at an end opposite to the handle body 82. The magnet 104 is oriented such that a north-south axis NS of the magnet 104 extends in a direction orthogonal to the central longitudinal axis CL of the main unit 12. The magnet 104 is oriented with the north pole 108 above the south pole 110 with the main unit 12 in the orientation of Figures 6 and 7. The Hall effect sensor 106 is a linear Hall effect sensor, and is mounted to the main body portion 98 of the first compaction handle connector 76, such that the Hall effect sensor 106 is spaced from the magnet 104. The Hall effect sensor 106 has a sensor face 112 that is generally planar in form. The sensor face 112 has a first axis that is generally parallel to the north-south axis NS of the magnet 104, and a second axis that is generally orthogonal to the north-south axis NS of the magnet 104 and to the central longitudinal axis CL of the main unit 12. The sensor face 112 can be thought of as facing generally towards the closure 36 of the bin assembly 18. The sensor face 112 is positioned so that the Hall effect sensor 106 can sense the magnetic field produced by the magnet 104. The Hall effect sensor 106 is in communication with a controller 120 of the motor assembly 26, as will be discussed in more detail hereinafter. The secondary separation system 24 is located downstream of the primary separation system 20, and is in fluid communication with the airflow passageway 46 defined by the U-shaped core 42. The secondary separation system 24 comprises a plurality of cyclonic separators 114 arranged about the central longitudinal axis CL of the main unit 12. Air outlets (not shown) of the plurality of cyclonic separators 114 are in fluid communication with the motor assembly 26. The motor assembly 26 comprises an electric motor 116, an impeller 118, and a controller 120. The electric motor 116 is configured to drive rotation of the impeller 118 in response to control signals from the controller 120. Although described here as part of the motor assembly 26, the controller 120 can form part of, or more generally be thought of, as a controller or a control system for the main unit 12. The motor assembly 26 is located within the housing portion 28, and the housing portion 28 comprises a filter assembly 122 and a user interface 124. The filter assembly 122 is removable from the housing portion 28, and is utilised to filter airflow both pre- and post-the motor assembly 26, by virtue of airflow passages formed when the filter assembly 122 is attached to the housing portion 28. The user interface 124 comprises an on-off button that causes the controller 120 to control the electric motor 116. In some examples, the user interface 124 can also comprise a display device, such as a screen, to indicate operating parameters of the appliance 10 to a user. Air outlets are formed on outer surfaces of the housing portion 28. The handle portion 30 is located below the housing portion 28, in the orientation seen in Figure 2, and is shaped and dimensioned to be receivable within a user’s hand. The battery assembly 32 comprises a battery pack 128 that is removable from the remainder of the main unit 12, for example to allow the battery pack 128 to be recharged and / or replaced. The battery pack 128 is electrically connected to the main unit 12 when the battery assembly 32 is connected to the handle portion 30 via one or more electrical contacts (not shown). Components of the main unit 12, such as the controller 120 and the electric motor 116, are configured to draw power from the battery pack 128 in use. Further details of the bin assembly 18, the primary separation system 20, the secondary separation system 24, the motor assembly 26, the housing portion 28, the handle portion 30, and the battery assembly 32, are not pertinent to the present application and so will not be described here for the sake of brevity. Appropriate examples of such features can be found, for example, in UK patent application no. 2309932.8. In use, a user operates the user interface 124 to turn on the main unit 12, and the controller 120 allows electrical power to be drawn from the battery pack 128 by the electric motor 116. The electric motor 116 drives rotation of the impeller 118 to generate an airflow within the main unit 12. The airflow is drawn into the bin 34 via the air inlet defined by the spigot 38, and flows over the U-shaped core 42. As airflow flows over the U-shaped core 42, it also flows over the mesh 44, and the mesh 44 acts to filter debris and dust from the airflow. Such filtered debris and dust collects within the debris collection chamber 37. The airflow passes through the apertures of the mesh 44 and along the airflow passageway 46 to the plurality of cyclonic separators 114. The plurality of cyclonic separators 114 act to further filter debris and dust from the airflow, with such debris and dust being collected in a dust collection chamber, for example a dust collection chamber located within the U-shaped core 42. Airflow then passes through and out of the electric motor 116, having been filtered pre- and post- the electric motor 116 by the filter assembly 122, before leaving the main unit 12 via the air outlets. As the user uses the appliance, debris and dust collects within the debris collection chamber 37. Once the debris and dust has reached a certain level within the debris collection chamber 37, the user may want to utilise the compaction mechanism 22 to compact debris and dust within the debris collection chamber 37, to enable the appliance 10 to be utilised for a longer time period before needing to empty the debris collection chamber 37. To utilise the compaction mechanism 22, the user first pivots the compaction handle 74 relative to the first 76 and second 78 compaction handle connectors, with the second projections 94 of the first 76 and second 78 compaction handle connectors sliding within the corresponding second apertures 90 of the first 84 and second 86 connection portions of the compaction handle 74. The compaction handle 74 pivots in a direction generally orthogonal to the central longitudinal axis CL of the main unit 12. Once the compaction handle 74 has pivoted to its maximum extent, the user can then push the compaction handle 74 in a direction parallel to the central longitudinal axis CL of the main unit 12. This causes the compaction plate sub-assembly 48 to slide within the bin 34, with the front plate 60 acting to compact debris and dust held within the debris collection chamber 37. At the same time, the core wiping member 50 wipes the U-shaped core 42 and the mesh 44, and the bin wiping member wipes an internal surface of the bin 34. It will be appreciated that it may be undesirable for suction of debris and dirt into the bin 34 to occur when such compaction and wiping is occurring. Accordingly, the controller 120 is configured to enable operation of the appliance 10 in different modes of operation depending on a position of the compaction handle 74, and more particularly depending on what direction of magnetic field produced by the magnet 104 is sensed by the Hall effect sensor 106. When the compaction handle 74 is in a default position, in which it has not been pivoted relative to the first 76 and second 78 compaction handle connectors, as shown in Figure 6, the magnet 104 is positioned relative to the Hall effect sensor 106 such that the sensor face 112 sees a first direction of magnetic field, generally from right to left as viewed in Figure 6. In response to the Hall effect sensor 106 sensing the first direction of magnetic field, the controller 120 enables power to be supplied to the electric motor 118 from the battery pack 128. The electric motor 118 is thereby able to operate with a non-zero speed, with a maximum speed of the electric motor 118 dependent on an operating mode of the appliance 10 set by a user using the user interface 124. When the compaction handle 74 is in a pivoted position, in which it has been pivoted relative to the first 76 and second 78 compaction handle connectors by a maximum pivoting extent, as shown in Figure 7, the magnet 104 is positioned relative to the Hall effect sensor 106 such that the sensor face 112 sees a second direction of magnetic field, generally from left to right as viewed in Figure 7. In response to the Hall effect sensor 106 sensing the second direction of magnetic field, the controller 120 inhibits electrical power from being supplied to the electric motor 118 from the battery pack 128. This can be done via a control scheme, or, for example, by breaking one or more electrical pathways in the appliance by opening a switch or the like. The electric motor 118 is therefore unable to operate, and hence the operating state of the appliance 10 as a whole can be considered to be an operating state with the electric motor 118 at zero speed. By enabling operation of the appliance 10 with the electric motor 118 at different motor speeds depending on which direction of magnetic field is sensed by the Hall effect sensor 106, the appliance has been found to provide an increased size of movement window relative to some arrangements that utilise sensed magnitude of magnetic flux as a control factor. This may lead to a reduced risk of accidental change in operation of the electric motor 118 in use, and can provide an improved user experience for a user of the appliance 10. For example, a graph illustrating tolerance bands around sensor output signals for an appliance that utilises sensed magnitude of magnetic flux as a control factor, when a magnet pivots away from a Hall effect sensor so that solely a magnitude of magnetic flux sensed by the sensor changes, is shown in Figure 8. This graph accounts for a 1.5mm variation on the mechanical positioning of the magnet relative to the sensor. A first line 131 indicates sensor output signal with magnet displacement at a default magnet position. A second line 133 indicates sensor output signal with magnet displacement at a first magnet position relative to the default position. A third line 135 indicates sensor output signal with magnet displacement at a second magnet position relative to the default position. A fourth line 137 indicates sensor output signal with magnet displacement at a third magnet position relative to the default position. As can be seen, due to variations in the sensor output as a result of the variation in mechanical positioning, there is a band 130 within which a closed signal can be determined, and a band 132 within which an open signal can be determined. Given mechanical tolerances and variations in sensor output, there is only a movement window of approximately 0.8mm within which to determine whether to enable or disable supply of power to the electric motor. In contrast, a graph illustrating tolerance bands around sensor output signals for the first embodiment of the appliance 10 is shown in Figure 9. This graph accounts for a 1.5mm variation on the mechanical positioning of the magnet relative to the sensor. A first line 139 indicates sensor output signal with magnet displacement at a default magnet position. A second line 141 indicates sensor output signal with magnet displacement at a first magnet position relative to the default position. A third line 143 indicates sensor output signal with magnet displacement at a second magnet position relative to the default position. A fourth line 145 indicates sensor output signal with magnet displacement at a third magnet position relative to the default position. As can be seen, due to variations in the sensor output as a result of the variation in mechanical positioning, there is a band 134 within which a closed signal can be determined, and a band 136 within which an open signal can be determined. Given mechanical tolerances and variations in sensor output, there is now a movement window of approximately 1.2mm within which to determine whether to enable or disable supply of power to the electric motor. When a user wishes to begin using the appliance 10 again, they can return the compaction handle 74 to its default position, and the controller 120 will then enable provision of power to the electric motor 118 again. The user can, in some examples, be required to utilise the user interface 124 to begin operation of the electric motor 118 again. An alternative arrangement of the sensor assembly 80 is illustrated in Figures 10 and 11, the magnet 104 is oriented such that the north-south axis NS of the magnet 104 extends in a direction parallel to the central longitudinal axis CL of the main unit 12. The magnet 104 is oriented with the north pole 108 to the left of the south pole 110 with the main unit 12 in the orientation of Figures 10 and 11. The alternative sensor assembly 80 is used in substantially the same manner as the first embodiment of the appliance 10, with the controller 120 configured to enable operation of the appliance 10 in different modes of operation depending on a position of the compaction handle 74, and more particularly depending on what direction of magnetic field produced by the magnet 104 is sensed by the Hall effect sensor 106. When the compaction handle 74 is in a default position, in which it has not been pivoted relative to the first 76 and second 78 compaction handle connectors, as shown in Figure 10, the magnet 104 is positioned relative to the Hall effect sensor 106 such that the sensor face 112 sees a first direction of magnetic field, generally from right to left as viewed in Figure 10. In response to the Hall effect sensor 106 sensing the first direction of magnetic field, the controller 120 enables power to be supplied to the electric motor 118 from the battery pack 128. The electric motor 118 is thereby able to operate with a non-zero speed, with a maximum speed of the electric motor 118 dependent on an operating mode of the appliance set by a user using the user interface 124. When the compaction handle is in a pivoted position, in which it has been pivoted relative to the first 76 and second 78 compaction handle connectors by a maximum pivoting extent, as shown in Figure 11, the magnet 104 is positioned relative to the Hall effect sensor 106 such that the sensor face 112 sees a second direction of magnetic field, generally from left to right as viewed in Figure 11. In response to the Hall effect sensor 106 sensing the second direction of magnetic field, the controller 120 inhibits electrical power from being supplied to the electric motor 118 from the battery pack 128. This can be done via a control scheme, or, for example, by breaking one or more electrical pathways in the appliance by opening a switch or the like. The electric motor 118 is therefore unable to operate, and hence the operating state of the appliance as a whole can be considered to be an operating state with the electric motor 118 at zero speed. A graph illustrating tolerance bands around sensor output signals for the alternative sensor assembly arrangement is shown in Figure 12. This graph accounts for a 1.5mm variation on the mechanical positioning of the magnet relative to the sensor. A first line 201 indicates sensor output signal with magnet displacement at a default magnet position. A second line 203 indicates sensor output signal with magnet displacement at a first magnet position relative to the default position. A third line 205 indicates sensor output signal with magnet displacement at a second magnet position relative to the default position. A fourth line 207 indicates sensor output signal with magnet displacement at a third magnet position relative to the default position. As can be seen, due to variations in the sensor output as a result of the variation in mechanical positioning, there is a band 202 within which a closed signal can be determined, and a band 204 within which an open signal can be determined. Given mechanical tolerances and variations in sensor output, there is now a movement window of approximately 1.5mm within which to determine whether to enable or disable supply of power to the electric motor. A second embodiment of an appliance 300 is illustrated schematically in Figures 13 to 16. The second embodiment of the appliance 300 has substantially the same structural features as the first embodiment of the appliance 10, save for the form of the compaction handle assembly and the operation of the appliance 300 and the sensor assembly. Like reference numerals will be used for sake of clarity. The appliance 300 has a compaction handle assembly 302 which is illustrated in Figures 14 to 16, and comprises a compaction handle 304, first 306 and second 308 compaction handle connectors, and a compaction sensor assembly 310. The compaction handle 302 comprises a handle body 312, and first 314 and second 316 connection portions that extend from the handle body 312. The handle body 312 is generally semi-circular in form. The first 314 and second 316 connection portions are located at opposite sides of the handle body 312, and comprise respective first apertures 318 and second apertures 320 that receive respective first projections 322 and second projections 324 formed on the first 306 and second 308 compaction handle connectors. The first apertures 318 and the first projections 322, and the second apertures 320 and the second projections 324 enable pivoting motion of the compaction handle 304 relative to the first 306 and second 308 compaction handle connectors, as will be described in more detail hereinafter. The first apertures 318 have a size substantially corresponding to a size of the first projections 322, whilst the second apertures 320 have a size bigger than a size of the second projections 324, so that the second projections 324 can slide within the second apertures 320. Each of the first 306 and second 308 compaction handle connectors comprises a handle connection portion 326, a main body portion 328, and a rod connection portion 330. The handle connection portions 326 have the respective first 322 and second 324 projections. The main body portions 328 are generally elongate in form, and extend between the respective handle connection portion 326 and the rod connection portion 328. The main body portion 328 of the first compaction handle connector 306 has a magnet receiving pocket 332 and a sensor receiving pocket 334. The magnet receiving pocket 332 and the sensor receiving pocket 334 are spaced apart to define a channel 336 within which a portion of the first connection portion 314 of the compaction handle 302 is received. The channel 336 has a width of around 3mm to 5mm. The rod connection portions 330 are upstanding from the main body portion 328, and comprise through-holes shaped and dimensioned to receive the respective first 54 and second 56 compaction rods. The compaction sensor assembly 310 is illustrated in Figures 14 to 16, and comprises a magnet 340, a Hall effect sensor 342, and a blocking member 344. The magnet 340 is a bar magnet, having a north pole 346 and a south pole 348. The magnet 340 is located within the magnet receiving pocket 332. The magnet 340 is oriented such that a north-south axis NS of the magnet 340 extends in a direction orthogonal to the central longitudinal axis CL of the main unit 12. The magnet 340 is oriented with the north pole 346 closer to the channel 336 than the south pole 348 with the main unit 12 in the orientation of Figures 15 and 16. The Hall effect sensor 342 is a linear Hall effect sensor, and is located within the sensor receiving pocket 334, such that the Hall effect sensor 342 is spaced from, and opposing, the magnet 340 at an opposite side of the channel 336. The Hall effect sensor 342 has a sensor face 350 that is generally planar in form. The sensor face 350 has a first axis that is generally parallel to the north-south axis NS of the magnet 340, and a second axis that is generally parallel to the central longitudinal axis CL of the main unit 12. The sensor face 350 is positioned so that the Hall effect sensor 342 can selectively sense the magnetic field produced by the magnet 340. The Hall effect sensor 342 is in communication with the controller 120 of the motor assembly 26, as will be discussed in more detail hereinafter. The blocking member 344 is a rectangular sheet of metal, having a thickness of around 1 or 2 mm. The height and width of the blocking member 344 are such that the blocking member 344 can block the magnetic field produced by the magnet 340 from reaching the Hall effect sensor 342 in certain configurations, as will be described in further detail hereinafter. The blocking member 344 is mounted to the first connection portion 314 of the compaction handle 304, and is positioned such that the blocking member 344 sits within the channel 336 defined between the magnet receiving pocket 332 and the sensor receiving pocket 334. The blocking member 334 is spaced from the Hall effect sensor 342 by around 2mm when the blocking member 334 is located within the channel 336. The second embodiment of the appliance 300 is used in substantially the same manner as the first embodiment of the appliance 10, with the controller 120 configured to enable operation of the appliance 10 in different modes of operation depending on a position of the compaction handle 304, but here more particularly depending on a magnitude of the magnetic flux of the magnetic field produced by the magnet 340 that is sensed by the Hall effect sensor 342. When the compaction handle 304 is in a default position, in which it has not been pivoted relative to the first 306 and second 308 compaction handle connectors, as shown in Figure 15, the blocking member 344 is positioned such that the blocking member 344 blocks the magnetic field produced by the magnet 340 from reaching the Hall effect sensor 342. This results in substantially no magnetic flux being sensed by the Hall effect sensor 342. In response to the Hall effect sensor 342 sensing no magnetic flux, the controller 120 enables power to be supplied to the electric motor 118 from the battery pack 128. The electric motor 118 is thereby able to operate with a non-zero speed, with a maximum speed of the electric motor 118 dependent on an operating mode of the appliance 10 set by a user using the user interface 124. As the compaction handle 304 pivots relative to the first 306 and second 308 compaction handle connectors, the blocking member 344 moves within the channel 336 such that magnetic flux from the magnet 340 is able to reach the Hall effect sensor 342. Once the level of magnetic flux sensed by the Hall effect sensor 342 is above a pre-determined threshold, the controller 120 inhibits electrical power from being supplied to the electric motor 118 from the battery pack 128. This can be done via a control scheme, or, for example, by breaking one or more electrical pathways in the appliance by opening a switch or the like. The electric motor 118 is therefore unable to operate, and hence the operating state of the appliance 300 as a whole can be considered to be an operating state with the electric motor 118 at zero speed. A fully pivoted position is illustrated schematically in Figure 16. A graph illustrating tolerance bands around sensor output signals for the second embodiment of the appliance 300 is shown in Figure 17. This graph accounts for a 1 5mm variation on the mechanical positioning of the sensor. As can be seen, due to variations in the sensor output as a result of the variation in mechanical positioning, there is a band 352 within which a closed signal can be determined, and a band 354 within which an open signal can be determined. Given mechanical tolerances and variations in sensor output, there is now a movement window of approximately 4mm within which to determine whether to enable or disable supply of power to the electric motor. Each of the embodiments of the appliance described above aim to provide an increased size of movement window relative to existing arrangement. It will be appreciated that variations to the embodiments of the appliance are also envisaged whilst still achieving this aim. For example, in the second embodiment of the appliance 300, the magnetic flux seen by the Hall effect sensor 342 increases as the compaction handle 304 is pivoted by a user. In alternative examples, the magnetic flux seen by the Hall effect sensor 342 may decrease as the compaction handle 304 is pivoted by a user, for example with the blocking member 344 moving to block the Hall effect sensor 344 as the compaction handle 304 is pivoted. In other examples, instead of disabling provision of power to the electric motor 118, the controller 120 can control the electric motor 118 to run at a lower speed than the speed at which the electric motor 118 is capable of running with the compaction handle in its default position. In other examples, turn-off of the electric motor 118 in response to any of the sensing mechanisms described herein can take place following actuation of other components of the appliance. For example, the appliance may comprise a closure opening mechanism configured to open the closure 36 relative to the bin 34. An example closure opening mechanism 400 illustrated schematically in Figure 18. The closure opening mechanism 400 comprises a linear push rod 402, and a push handle 404 pivotally mounted to the linear push rod 402. The closure opening mechanism 402 can comprise any of the sensor and magnet arrangements described herein such that, when the push handle 404 is pivoted relative to the linear push rod 402, a controller of an appliance comprising the closure opening mechanism 400 can disable provision of power to an electric motor of the appliance. The user can then push the push handle 404 to linearly move the linear push rod 402 to contact the closure 36 to open the closure 36 relative to the bin 34. In another example, removal, or partial removal, of the filter assembly 122 from the housing portion 28, can be utilised to disable provision of power to the electric motor 118. An example filter assembly 500 and housing portion 502 is shown schematically in Figure 19. Here, a magnet 504 is fixed to the filter assembly 500, and a Hall effect sensor 506 is fixed to the housing portion 502. The housing portion 502 protrudes into the filter assembly 500, and the filter assembly 500 is rotatable relative to the housing portion 502 before being linearly removable from the housing portion 502, and such rotation causes rotation of the magnet 504 relative to the Hall effect sensor 506. This causes the Hall effect sensor 506 to sense a different direction of magnetic field in a manner similar to that described in relation to the first embodiment of the appliance 10 above, and enables selective provision of electrical power to an electric motor of an appliance comprising the filter assembly 500 and housing portion 502 in the manner previously described in relation to Figures 6 and 7, and 10 and 11. A further example filter assembly 600 and housing portion 602 is shown schematically in Figure 20. Here, a magnet 604 and a sensor 606 are fixed to the housing portion, and a blocking member 608 is fixed to the filter assembly 600. The blocking member 608 is positioned on the filter assembly 600 such that with the filter assembly 600 attached to the housing portion 602 in an operable configuration, the blocking member 608 is located between the magnet 604 and the sensor 606. This inhibits the sensor 606 from sensing magnetic flux produced by the magnet 604, in a manner similar to that described in relation to Figure 15 above. When the filter assembly 600 is rotated relative to the housing portion 602, the blocking member 608 moves from its position between the magnet 604 and the sensor 606, so that the sensor 606 can sense the magnetic flux produced by the magnet 604. This enables selective provision of electrical power to an electric motor of an appliance comprising the filter assembly 600 and housing portion 602 in the manner previously described in relation to Figures 15 and 16. 5 Although described above in the context of a vacuum cleaner, it will be appreciated that the teachings discussed herein can also be applied, where appropriate, to other forms of appliance. For example, selective provision of electrical power to an electric motor of an appliance can be utilised in the context of a haircare appliance, where removal of a filter 10 assembly can determine that provision of electrical power should be inhibited.

Claims

1. An appliance comprising:an electric motor;a magnet;a sensor configured to sense a direction of a magnetic field produced by the magnet; anda controller configured to enable operation of the appliance with the electric motor at a first motor speed in response to a first direction of magnetic field sensed by the senor, and to enable operation of the appliance with the electric motor at a second motor speed in response to a second direction of magnetic field sensed by the sensor, the second direction of magnetic field different to the first direction of the magnetic field, and the second motor speed lower than the first motor speed.

2. An appliance as claimed in Claim 1, wherein the second motor speed is zero.

3. An appliance as claimed in Claim 1 or Claim 2, wherein the controller isconfigured to disable provision of power to the electric motor from a power supply in response to the second direction of magnetic field sensed by the sensor.

4. An appliance as claimed in any one of the preceding claims, wherein the appliance is configured to enable relative movement between the magnet and the sensor.

5. An appliance as claimed in any one of the preceding claims, wherein the appliance comprises a movable member, and the magnet is fixedly attached to the movable member such that movement of the movable member moves the magnet relative to the sensor.

6. An appliance as claimed in any one of the preceding claims, wherein the appliance is a vacuum cleaner, and the appliance comprises:a bin for collecting dust;a body movable within the bin to interact with dust collected in the bin; anda closure that selectively closes the bin,wherein the controller is configured to enable operation of the appliance with the electric motor at the second motor speed when at least one of the body moves within the bin, and the closure is opened to open the bin.

7. An appliance as claimed in Claim 6, wherein the appliance comprises a movable member configured to cause movement at least one of the body and the closure in response to movement of the movable member by a user of the appliance, and one of the magnet and the sensor is fixedly attached to the movable member.

8. An appliance as claimed in Claim 7, wherein the movable member is configured to cause movement of the body, the magnet is fixedly attached to the movable member, the movable member is movable in a first direction orthogonal to a second direction in which the body moves within the bin, and movement of the movable member in the first direction moves the magnet relative to the sensor.

9. An appliance as claimed in Claim 8, wherein the sensor comprises a sensor face oriented in a plane having a first axis parallel to the first direction and a second axis orthogonal to the first direction and the second direction, and the magnet is oriented such that a north-south axis of the magnet is substantially parallel to the second direction.

10. An appliance as claimed in Claim 8, wherein the sensor comprises a sensor face oriented in a plane having a first axis parallel to the first direction and a second axis orthogonal to the first direction and the second direction, and the magnet is oriented such that a north-south axis of the magnet is substantially parallel to the first direction.

11. An appliance as claimed in any one of Claims 6 to 10, wherein the appliance comprises a compaction mechanism for compacting dust collected within the bin, and the body defines a compaction plate of the compaction mechanism.

12. An appliance as claimed in any one of Claims 6 to 11, wherein the appliance comprises a bin wiping mechanism for wiping dust from at least one of an internal surfaceof the bin and surfaces of components contained within the bin, and the body defines a wiping member of the bin wiping mechanism.

13. An appliance as claimed in any one of Claims 6 to 12, wherein the appliance 5 comprises a closure opening mechanism, and movement of the movable member in the second direction causes actuation of the closure opening mechanism to open the closure relative to the bin.

14. An appliance as claimed in any one of the preceding claims, wherein the appliance 10 comprises a removable filter, and movement of the filter to remove the filter from a main body of the appliance causes a direction of the magnetic field sensed by the sensor to change.

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