GB2600928A

GB2600928A - A nail polish conditioning system

Info

Publication number: GB2600928A
Application number: GB2017674.9A
Authority: GB
Inventors: Simmons David; Grace John; Liddell Andrew
Original assignee: Intelligent Beauty Products Ltd
Current assignee: Intelligent Beauty Products Ltd
Priority date: 2020-11-09
Filing date: 2020-11-09
Publication date: 2022-05-18
Also published as: WO2022096902A1; GB202017674D0

Abstract

Stirring nail polish may utilise a magnetic stirrer 2 and magnetic stir bar 4. A motor in the stirrer 2 can rotate magnets (17, fig 2); rotating stir bar 4 in a bottle. The stirrer 2 can sense magnetic decoupling of the stir bar 4 and rotatable magnetic device (17, fig 2), and decelerate the rotation speed to help re-engage magnetic coupling again. The stirrer 2 can monitor changes in viscous resistance of the liquid nail polish. A controller may slow down the motor, to re-establish magnetic coupling, e.g., upon sensing exceeding a torque threshold; sensed rotational speed change; or current change. Motor speed may increase if decoupling is not sensed. Upon re-establishing magnetic coupling, rotational speed may increase to a value lower than when decoupling occurred. Counterfeit detection may include RFID tags and barcodes. Data may be shared wirelessly. Magnetic retriever 6 can remove stir bars 4 from bottles.

Description

A NAIL POLISH CONDITIONING SYSTEM

TECHNICAL FIELD

The present disclosure relates to a nail polish conditioning system. Aspects of the invention relate to a magnetic stirring apparatus, to a magnetic stir bar, and to a nail polish conditioning system.

BACKGROUND

Nail polish, also known as nail varnish or lacquer, is typically stored in a bottle with a brush, or applicator, attached to an underside of a lid for applying the nail polish to a fingernail or toenail. The bottles are available in a wide range of shapes, including square, round, spherical and oval shapes, that generally hold a small volume of nail polish. For example, the bottles are often either tall and skinny, or fat and squat, and include a relatively narrow bottle neck for removing excess nail polish from the applicator.

Different types of nail polish are available, including base coats, top coats, gel polish and matte polish, but typically the nail polish consists of a film-forming polymer dissolved in a volatile organic solvent. It is common that, over time, the solvent will separate out of the mixture and evaporate, particularly when left to settle and/or exposed to heat. As the level of solvent decreases, the nail polish thickens and becomes more viscous, leading to poor adhesion and application characteristics.

A user may shake the nail polish bottle in an attempt to encourage mixing and to prolong the useful life of the nail polish. However, in order to fully mix the nail polish, it is necessary to shake the bottle for a long period of time -often much longer than a user is prepared to perform by hand.

To mitigate this problem, it is known for nail polish bottles to include ball bearings, or small metallic agitators, arranged inside the bottle to encourage mixing when the bottle is shaken. However, the ball bearings do not entirely solve the problem and it is common for the ball bearings to remain stuck in suspension as the bottle is shaken, particularly with relatively thick gel polish. This limits the ability of the ball bearings to effectively improve the mixing of the nail polish.

Even if the nail polish bottle is adequately shaken, another problem is that such shaking encourages air bubbles to form, which impair the ordinary application of the nail polish, producing a streaky coating.

It is an aim of the present invention to address one or more of the above disadvantages.

SUMMARY OF THE INVENTION

According to an aspect of the invention there is provided a magnetic stirring apparatus of a nail polish conditioning system. The magnetic stirring apparatus is configured to receive a receptacle for a volume of nail polish with a magnetic stir bar arranged inside the receptacle. The magnetic stirring apparatus comprises: one or more magnetic devices configured to generate a magnetic field for magnetically coupling the stir bar to the one or more magnetic devices; a motor configured to rotate the one or more magnetic devices about an axis of rotation and thereby to produce a rotating magnetic field for rotating the magnetically coupled stir bar inside the receptacle; and a control system for controlling the motor, the control system comprising: a controller configured to control a rotational speed of the motor and thereby to control a rotational speed of the rotating magnetic field; and a sensor arrangement configured to generate a sensor signal indicative of a state of the magnetic coupling; wherein the sensor arrangement is configured to output the sensor signal to the controller and the controller is configured to control the rotational speed of the motor based, at least in part, on the sensor signal.

In this manner, the magnetic stirring apparatus is configured to generate a magnetic field and to control the rotation of that magnetic field in dependence on the state of the magnetic coupling to / with the stir bar. For example, the magnetic stirring apparatus may decelerate, or stop, the rotation of the magnetic field if the stir bar decouples from the one or more magnetic devices in order to (more quickly! efficiently) re-establish the magnetic coupling. Once re-established, the magnetic stirring apparatus may proceed to increase the rotational speed of the rotating magnetic field once again to resume effective stirring. This has the advantage of effectively stirring the volume of nail polish to prolong its usable life and restore the nail polish to a desirable condition.

In an example, the sensor signal may be indicative of at least one of: a rotational speed of the motor; a rotational speed of the rotating magnetic field; a motor current demand; a difference between the rotational speed of the motor, or the rotating magnetic field, and the rotational speed of the stir bar; and/or a torque causing the one or more magnetic devices to rotate about the axis of rotation. Each of these signals may be indicative of the state of the magnetic coupling alone or in combination.

The sensor signal may, for example, be indicative of a change in the state of the magnetic coupling in dependence on a change of the sensor signal exceeding a state change threshold. The state change threshold may, for example, be used to distinguish changes in the state of the magnetic coupling from ordinary fluctuations in the sensory signal.

Optionally, the controller is configured to increase the rotational speed of the motor towards a target stirring speed in dependence on the sensor signal being indicative of a magnetically coupled state.

The controller may, for example, be configured to increase the rotational speed of the motor incrementally. In this manner, the controller may be configured to monitor the state of the magnetic coupling after each increment of rotational speed to decide whether to proceed to controlling the subsequent increment.

In an example, the controller may be configured to increase the target stirring speed from a first target stirring speed to a higher, second target stirring speed in dependence on the sensor signal indicating the magnetically coupled state for a threshold period of time whilst the motor rotates at the first target stirring speed.

In an example, the controller may be configured to reduce the target stirring speed in dependence on the sensor signal being indicative of the magnetically uncoupled state.

In this manner, once the magnetic coupling is re-established, the controller may (for at least a defined period of time) control the rotational speed of the magnetic field to a speed that is below the rotational speed at which the magnetic coupling previously failed.

The controller may, for example, be configured to determine the reduced target stirring speed based on the rotational speed of the motor preceding the indication of the magnetically uncoupled state. In this manner, once the magnetic coupling is reestablished, the controller may increase the rotational speed of the magnetic field to a speed at which the magnetic coupling was previously maintained.

Optionally, the controller is configured to reduce the rotational speed of the motor to an idle speed in dependence on the sensor signal being indicative of a magnetically uncoupled state.

The controller may, for example, be configured to control a step reduction of the rotational speed of the motor to the idle speed.

In an example, the idle speed may be suitable for magnetically coupling the stir bar to the one or more magnetic devices.

Optionally, the controller is configured to generate a pulse-width modulated current signal for controlling the rotational speed of the motor. In this manner, the pulse-width of the current signal may be varied to control the rotational speed of the motor.

Optionally, the one or more magnetic devices comprises a pair of magnets spaced equidistantly about the axis of rotation. In this manner, the pair of magnets produce a rotating magnetic field when rotated about the axis of rotation. The distance between centres of the magnetic devices may be at least 10 mm, preferably at least 15 mm, but generally not more than 25 mm. The magnets may be electromagnetic devices or may be permanent magnets. Conveniently, the magnetic devices are permanent magnets.

In an example, the magnetic stirring apparatus may further comprise an indicator device for indicating the state of the magnetic coupling and/or an operational phase of the magnetic stirring apparatus to a user of the magnetic stirring apparatus. The control system may, for example, be configured to control the indicator device based, at least in part, on the sensor signal. In this manner, the state of the magnetic coupling can be indicated to a user to check the performance of the magnetic stirring apparatus.

Optionally, the indicator device comprises one or more light sources configured to generate a light output; and/or one or more sound sources configured to generate an audible output.

The one or more light sources may, for example, include a plurality of light sources arranged in a ring. The magnetic stirring apparatus may, for example, further comprise a cover, configured to rotate with the one or more magnetic devices so as to temporarily obscure the light output from successive ones of the plurality of light sources as the one or more magnetic devices rotate.

In an example, the controller may be configured to control the one or more light sources to output a light signal based on the state of the magnetic coupling.

Optionally, the controller may be configured to control the one or more light sources to output a light signal based on an operational phase of the magnetic stirring apparatus.

In an example, the magnetic stirring apparatus may comprise a docking station for receiving the receptacle. The docking station may, for example, be shaped so as to be complementary to a base shape of the receptacle.

Optionally, the docking station is releasably secured to the magnetic stirring apparatus for receiving the receptacle. For example, the docking station may be selected from a plurality of docking stations for receiving respective receptacles.

In an example, the control system may further comprise an anti-counterfeiting sensor for recognising an identification tag on the receptacle. If an identification tag is not recognised in use, then the control system may communicate information that is indicative that the receptacle and/or its contents are counterfeit and/or to disable the magnetic stirring apparatus while a counterfeit receptacle is on the docking station.

Optionally, the anti-counterfeiting sensor may comprise at least one of: a radio-frequency identification device; a barcode reader; and/or a OR code reader.

In an example, the control system may further comprise a communication module connectable to an external server to communicate information associated with the receptacle and/or the magnetic stirring apparatus between the control system and the external server.

The communication module may, for example, take the form of a wireless communication module configured to form a wireless connection to the external server.

Optionally, the information associated with the receptacle and/or the magnetic stirring apparatus includes at least one of: an identification of a user of the magnetic stirring apparatus; a record of use of the magnetic stirring apparatus; an identification of the receptacle; a type of nail polish inside the receptacle; and/or a volume of nail polish inside the receptacle.

According to another aspect of the invention there is provided a magnetic stir bar of a nail polish conditioning system. The stir bar is insertable into a nail polish bottle and rotatable inside the nail polish bottle by a rotating magnetic field to condition a volume of nail polish inside the nail polish bottle.

In this manner, the magnetic stirring bar is shaped for insertion into a nail polish bottle, which typically has a relatively narrow bottle neck, and the magnetic stir bar is rotatable inside the nail polish under the influence of a rotating magnetic field to suitably stir, and thereby condition, a volume of nail polish inside the nail polish bottle. This has the effect of prolonging the usable life of the nail polish, effective mixing the nail polish to soften any hardened nail polish and restore the nail polish to a desirable condition.

The stir bar may, for example, comprise: a magnetic element configured to produce a magnetic field; and a non-magnetic shell that defines a shape of the stir bar. The shell may comprise: a housing portion that encases the magnetic element; and a first end portion and a second end portion that extend from opposing ends of the housing portion to first and second respective ends of the stir bar. The first and second end portions may be shaped such that the magnetic field around the stir bar has a lower magnetic field strength at each of the first and second end portions than at the housing portion. In this manner, metallic ball bearings commonly found in nail polish bottles are attracted to the housing portion of the stir bar, and not the end portions, allowing for efficient stirring of the nail polish and endwise removal of the stirring bar from the nail polish bottle with reduced or eliminated instances of jamming.

Optionally, the first and second end portions are shaped so that the magnetic field has a magnetic field strength at each of the first and second ends of the stir bar that is less than 50% of the magnetic field strength at the housing portion.

The first and second end portions may, for example, be shaped so that the magnetic field has a magnetic field strength at each of the first and second ends of the stir bar that is less than 25% of the strength at the housing portion. Optionally, the first and second end portions may, for example, be shaped so that the magnetic field has a magnetic field strength at each of the first and second ends of the stirring bar that is less than 20%, less than 15% or less than 10% of the strength at / adjacent the housing portion.

Optionally, the first and second end portions are shaped so that the magnetic field has negligible strength at each of the first and second ends of the stirring bar.

In an example, each of the first and second end portions may have a length that is at least 50% of a length between the opposing ends of the housing portion. Each of the first and second end portions may, for example, have a length that is at least 75% of the length between the opposing ends of the housing portion. Optionally, each of the first and second end portions may have a length that is at least two, and preferably at least four times greater than the thickness / width of the shell at the housing portion.

Optionally, the housing portion may be cylindrical. Each of the first and second end portions may, for example, taper away from the cylindrical portion towards a respective one of the first and second ends of the shell. Each of the first and second end portions may, for example, have a rounded conical shape. The tapered shape of the end portions may allow for ease of endwise removal of the stir bar, as metallic ball bearings in the nail polish may be guided along the tapered surfaces to the tip where the lowest magnetic field strength from the magnetic element is experienced.

The shell may, for example, include a recess that extends from one of the first and second ends, through the respective end portion, towards the magnetic element.

The recess may, for example, be configured to receive a magnetic end of a stir bar retriever of the nail polish conditioning system for magnetically attracting the stir bar to the stir bar retriever. In this manner, the magnetic end of the stir bar retriever can be inserted from one end of the stir bar into the recess and moved towards the magnetic element, where the magnetic field strength is stronger. This allows for convenient removal of the stir bar with strong attraction between the stir bar and the stir bar retriever.

Optionally, the recess defines a groove that extends diametrically across that end of the shell so that the stir bar retriever is insertable into the recess from opposing sides of the magnetic stir bar. This may allow for side-to-end or end-to-end connection between the magnetic end of the stir bar retriever and the magnetic stir bar.

The groove may, for example, taper inwardly towards the housing portion to guide the magnetic end of the stir bar retriever towards the magnetic element.

Optionally, the groove includes one or more guiding formations for guiding the magnetic end of the stir bar retriever towards the magnetic element.

According to a further aspect of the invention there is provided a nail polish conditioning system comprising: a magnetic stir bar insertable into a receptacle for a volume of nail polish; and a magnetic stirring apparatus configured to receive the receptacle and to generate a rotating magnetic field for rotating the magnetic stir bar inside the receptacle to condition the volume of nail polish.

In this manner, the stir bar is insertable into a receptacle, such as a nail polish bottle, that the magnetic stirring apparatus receives and applies a rotating magnetic field to in order to rotate the stir bar and stir the nail polish to produce a more homogenous polish.

Optionally, the stir bar may take the form of a magnetic stir bar as described in a previous aspect of the invention.

In an example, the nail polish condition system may, for example, further comprise a stir bar retriever including a magnetic end that is insertable into the receptacle for removing the stir bar.

Optionally, the stir bar retriever is elongate and generally cylindrical, with the magnetic end being arranged at one end of the stir bar retriever and sufficiently long so as to be insertable into the receptacle whilst the stir bar retriever remains, at least partially, outside the receptacle for removing the stir bar from the receptacle.

The magnetic end of the stir bar retriever may, for example, have a shape / profile that is complementary to the recess provided in a stir bar, and is insertable into the recess to magnetically attract the stir bar to the stir bar retriever.

In an example, the magnetic stirring apparatus of the nail polish conditioning system may take the form of a magnetic stirring apparatus as described in a previous aspect of the invention.

Within the scope of this application it is expressly intended that the various aspects, embodiments, examples and alternatives set out in the preceding paragraphs, in the claims and/or in the following description and drawings, and in particular the individual features thereof, may be taken independently or in any combination. That is, all embodiments and/or features of any embodiment can be combined in any way and/or combination, unless such features are incompatible. The applicant reserves the right to change any originally filed claim or file any new claim accordingly, including the right to amend any originally filed claim to depend from and/or incorporate any feature of any other claim although not originally claimed in that manner.

BRIEF DESCRIPTION OF THE DRAWINGS

One or more embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which: Figure 1 shows a nail polish conditioning system in accordance with an embodiment of the invention, Figure 2 shows an example magnetic stirring apparatus according to an embodiment of the invention, which may form part of the nail polish conditioning system shown in Figure 1; Figure 3 shows a perspective view of an example magnetic stir bar according to an embodiment of the invention, which may form part of the nail polish conditioning system shown in Figure 1; Figure 4 shows a cross-sectional view of the example magnetic stir bar shown in Figure 3; Figure 5 shows a stir bar retriever according to an embodiment of the invention, which may form part of the nail polish conditioning system shown in Figure 1; Figure 6 shows an example method of conditioning a volume of nail polish using the nail polish conditioning system shown in Figure 1; Figures 7 to 9 illustrate respective steps of the method shown in Figure 6; Figures 10 to 14 illustrate successive steps for removing the magnetic stir bar from a receptacle using the stir bar retriever; and Figure 15 shows another example magnetic stirring apparatus according to an embodiment of the invention, which may form part of the nail polish conditioning system shown in Figure 1.

DETAILED DESCRIPTION

Embodiments of the invention relate to a nail polish conditioning system for conditioning a volume of nail polish retained inside a receptacle, such as a conventional nail polish bottle.

It is envisaged that the invention will provide a user, such as a manicurist, with a homogenous polish, enabling a repeatable streak-and lump-free application of the polish that requires minimal rework It will also prolong the usable life of a volume of nail polish, providing effective mixing to soften hardened nail polish and restore the nail polish to a desirable condition.

A nail polish conditioning system in accordance with an embodiment of the present invention is described herein with reference to the accompanying Figures 1 to 14.

Figure 1 schematically illustrates a nail polish conditioning system 1 in accordance with an embodiment of the present invention.

The nail polish conditioning system 1 is configured to condition a volume of nail polish retained inside a receptacle 7. The volume of nail polish may have separated and hardened to some extent, albeit retaining properties that are typical of viscous fluids.

In the illustrative example shown in Figure 1, the receptacle 7 takes the form of a conventional nail polish bottle having a cylindrical body 8, a relatively narrow bottle neck 9 and a lid 10. For context, the cylindrical body 8 of the nail polish bottle may have a capacity of between 5 ml and 50 ml and the bottle neck 9 may define an opening that is between about 5 mm and 10 mm in diameter.

As is typical for conventional nail polish bottles, the receptacle 7 may include one or more metallic ball bearings 11 that are submerged in the volume of nail polish and configured to agitate the mixture when displaced. Typical nail polish bottles may include a pair of such ball bearings 11, as shown in Figure 1, and each ball bearing 11 may have a diameter of between about 3 mm and 6 mm.

The lid 10 of the receptacle 7 may include a brush 12, or applicator, for applying the nail polish to a nail and the brush 12 may be attached to an underside of the lid 10 in a conventional manner, as shown.

This conventional nail polish bottle provides a relevant example of a typical application of the nail polish conditioning system 1. However, the example is not intended to be limiting on the scope of the invention. In other examples, the receptacle 7 may take any other suitable form and shape -for example, the nail polish receptacle may have a round, oval, square, rectangular or triangular cross-section.

As shown in Figure 1, the nail polish conditioning system 1 includes a magnetic stirring apparatus 2, a magnetic stir bar 4 and a stir bar retriever 6.

The magnetic stirring bar 4 is suitable for insertion into the receptacle 7, for example, via the bottle neck 9. The magnetic stirring apparatus 2 is configured to receive the receptacle 7 and to generate a rotating magnetic field that interacts with the magnetic stir bar 4 to form a magnetic coupling for rotating the magnetic stir bar 4 inside the receptacle 7.

The rotation of the magnetic stir bar 4 acts to stir, and thereby condition the volume of nail polish. As shall become clear, the magnetic stirring apparatus 2 is advantageously configured to control a rotational speed of the rotating magnetic field so as to form, and maintain, the magnetic coupling as the magnetic stir bar 4 is driven to a suitable rotational speed for effective stirring of the volume of nail polish.

Once suitably conditioned, the magnetic stir bar 4 may be conveniently removed from the volume of nail polish by inserting the stir bar retriever 6 into the receptacle 7 and engaging the magnetic stir bar 4 with a magnetic end 13 of the stir bar retriever 6.

Thereafter, the magnetic stir bar 4 may be cleaned and reused, for example, to condition another volume of nail polish.

Figure 2 schematically illustrates an example of the magnetic stirring apparatus 2 in accordance with an embodiment of the invention.

In this example, the magnetic stirring apparatus 2 has a generally truncated ovoid shape defined by a housing 14 that extends from a substantially flat base 15 to a platform 16 for receiving the receptacle 7.

The platform 16 may include a docking region! area 19 (not shown in Figure 2) which may take various forms and shapes for receiving the receptacle 7. For example, the docking region 19 may be shaped in a complementary manner to the form, or body, of the base of any conventional nail polish bottle and the platform 16 may define a raised edge (not shown) that extends around a perimeter of the docking region 19 for retaining the receptacle 7. In this example, as better depicted in Figures 7 to 9, the platform 16 defines a circular docking region 19 for receiving and supporting the cylindrical body 8 of the receptacle 7.

Inside the housing 14, the magnetic stirring apparatus 2 includes: one or more magnetic devices 17a,b; a motor 18; and a control system 20 for controlling the motor 18.

The one or more magnetic devices 17a,b are arranged proximal to the platform 16, suitably below the docking region 19, and the one or more magnetic devices 17a,b are configured to generate a first magnetic field that extends through the platform 16 to reach the inner volume of the receptacle 7 (not shown in Figure 2). In this manner, the first magnetic field can form a magnetic connection to the magnetic stir bar 4 (arranged inside the receptacle 7).

For example, when the magnetic stir bar 4 is arranged inside the receptacle 7 on the platform 16, the first magnetic field may overlap, and interact with, a second magnetic field, generated by the magnetic stir bar 4. The interaction between the first and second magnetic fields may form a magnetic connection between the magnetic stir bar 4 and the one or more magnetic devices 17a,b. The magnetic connection couples the magnetic stir bar 4 to the one or more magnetic devices 17a,b despite their physical separation. By magnetic connection' it is meant that the magnetic field generated by the one or more magnetic devices 17a,b interacts with the magnetic field generated by the magnetic stir bar 4 such that a magnetic attractive force exists between the two, which attempts to urge the one or more magnetic devices 17a,b and the magnetic stir bar 4 towards each other. Further, by coupled' it is meant that the magnetic connection / attraction between the one or more magnetic devices 17a,b and the magnetic stir bar 4 is such that rotation (or movement) of the magnetic field generated by the one or more magnetic devices 17a, b causes a corresponding rotation (or movement) of the magnetic stir bar 4.

It shall be appreciated that the one or more magnetic devices 17a,b are therefore configured to generate a magnetic field with sufficient strength to extend through the platform 16, the docking region 19, and a base of the receptacle 7 to reach the magnetic stir bar 4 and to form a magnetic coupling therewith.

For context, the distance separating the magnetically coupled one or more magnetic devices 17a,b and the magnetic stir bar 4 may be at least 5 mm in use, for example, more than 10 mm, more than 12 mm or more than 15 mm, depending on the thickness of the base of the receptacle 7 and the platform 16. Conventional nail polish bottles typically have a base thickness of between 3 mm and 8 mm. Hence, in use, the distance separating the one or more magnetic devices 17a,b and the magnetic stir bar 4 may typically be between 5 mm and 15 mm, for example the distance may be between 6 mm and 11 mm. Accordingly, the one or more magnetic devices 17a,b may be configured to generate a magnetic pull force of at least 0.1 kg at a distance of at least 10 mm in order to form a suitable magnetic coupling with the magnetic stir bar 4.

In this example, the one or more magnetic devices 17a,b take the form of a pair of permanent magnets 17a,b supported on a rotatable motor arm 22. The pair of permanent magnets 17a,b may, for example, each take the form of an N52 magnet with a rated magnetic pull force of at least 3 kg, preferably at least 4 kg.

In this example, the motor arm 22 is generally circular but, in other examples, the motor arm 22 may take any other suitable form, such as a generally linear bar. A motor shaft 24 of the motor 18 connects to a centre of the motor arm 22 and the pair of permanent magnets 17a,b are supported in respective positions either side of the motor shaft 24. Suitably, in this embodiment, each of the magnetic devices 17a,b is arranged on the rotatable arm 22 in opposing magnetic pole orientations. For example, one (e.g. 17a) with its north pole opposing the underside of the platform 16, and the other (e.g. 17b) with its south pole opposing the underside of the platform 16. In this manner, the pair of permanent magnets 17a,b defines a pair of opposing magnetic poles of the first magnetic field that are equally offset from, and therefore symmetric about, an axis of the motor (i.e. a motor axis), which extends transversely to the platform 16. The distance between the pair of opposing magnetic poles will correspond to the size and shape of the magnetic stir bar 4 and, in turn, the receptacle 7. Accordingly, the distance between centres of the magnetic devices 17a,b may be at least 10 mm, preferably at least 15 mm, but generally not more than about 25 mm for a conventional nail polish bottle. For example, the distance between the pair of magnetic devices 17a,b may be about 15 mm, about 16 mm, about 18 mm, about 19 mm or about 20 mm (and may preferably be between about 16 and 19 mm).

In other examples, the one or more magnetic devices 17a,b may include one or more permanent magnets or electromagnetic devices arranged to provide at least one pair of opposing magnetic poles arranged equidistantly about the motor axis, i.e. with a north pole arranged on one side of the motor axis, and a south pole arranged on a diametrically opposing side of the motor axis, the north and south poles being spaced equidistantly from the motor axis. Hence, it shall be appreciated that the example arrangement described above is not intended to be limiting on the invention.

The motor 18 is configured to rotate the pair of permanent magnets 17a,b about the motor axis and thereby to cause the first magnetic field to rotate. For this purpose, the motor 18 may provide a torque input to the motor shaft 24. For example, the motor 18 may take the form of a DC motor configured to receive a current signal and to generate a corresponding torque input at the motor shaft 24.

The rotation of the first magnetic field forms a rotating magnetic field centred on the motor axis. As shall become clear, the rotating magnetic field is configured to transfer torque to the magnetic stir bar 4, via the magnetic connection. In this manner, the rotating magnetic field causes a suitably coupled magnetic stir bar 4 to rotate, inside the receptacle 7, synchronously with the pair of permanent magnets 17a,b about the motor axis. Herein, this form of magnetic connection (which is able to transfer torque between the pair of permanent magnets 17a,b and the magnetic stirring bar 4) shall be referred to as a 'magnetic coupling'.

The control system 20 is configured to control the motor 18 and thereby to control the rotation of the first magnetic field. In particular, the control system 20 is configured to control a rotational speed, and/or a torque, of the motor 18 and thereby to control a rotational speed of the rotating magnetic field. In turn, the control system 20 is therefore configured to control the rotation of the magnetic stir bar 4 inside the receptacle 7.

Considered in more detail, the control system 20 is configured to control the rotational speed of the rotating magnetic field so as to optimise the ability of the magnetic stir bar 4 to spin, and thereby stir / mix and condition, the volume of nail polish. Such optimisation is provided by maintaining the magnetic coupling as the magnetic stir bar 4 is driven to a desired, effective stirring speed.

For the sake of clarity, it shall be appreciated that the rotation of the magnetic stir bar 4 is resisted by the viscous nail polish inside the receptacle 7 and may also be resisted, or otherwise disturbed, by contact between the magnetic stir bar 4 and the metallic ball bearings 11, and/or the brush 12 Of either or both are present), as the magnetic stir bar 4 rotates.

The viscous resistance, or viscous torque, of the volume of nail polish generally increases with the rotational speed of the magnetic stir bar 4, but the volume of nail polish is unconditioned and non-homogenous. Hence, as the volume of nail polish is stirred, relatively high viscosity fluids may be mixed with relatively low viscosity fluids producing significant changes in the viscous resistance of the volume of nail polish.

For such reasons, it shall be appreciated that the resistance to the rotation of the magnetic stir bar 4 is difficult to accurately predict and the resistance may depend on several factors, including the rotational speed of the magnetic stir bar 4.

If the resistance to the rotation of the magnetic stir bar 4 becomes too large, the magnetic stir bar 4 will decouple, and separate, from the pair of permanent magnets 17a,b. For example, the magnetic coupling between the pair of permanent magnets 17a,b, and the magnetic stir bar 4 may have a torque threshold, which sets a maximum torque difference between the resultant torque acting on the magnetic stir bar 4 and the resultant torque urging the pair of permanent magnets 17a,b to rotate. Hence, if the resistance torque acting on the magnetic stir bar 4 becomes too large, the torque threshold may be exceeded and the magnetic stir bar 4 may be uncoupled from the magnetic field generated by the pair of permanent magnets 17a,b.

Once uncoupled, the pair of permanent magnets 17a,b may continue to rotate under the control of the motor 18, but the rotating magnetic field will no longer drive rotation of the magnetic stir bar 4. Instead, the magnetic stir bar 4 may come to a rest.

Often, the magnetic coupling can only be re-established by reducing the torque input, and/or reducing the rotational speed of the rotating magnetic field. For example, the rotational speed of the rotating magnetic field may be substantially reduced, or even stopped, so that the torque difference reduces below the torque threshold and the magnetic coupling can be re-established.

In an example, the control system 20 may therefore be configured to control the motor 18 based, at least in part, on a state of the magnetic coupling, i.e. based on whether the magnetic stir bar 4 is magnetically coupled to, or uncoupled from, the magnetic field generated by the pair of permanent magnets 17a,b.

For example, once the magnetic coupling is established, the control system 20 may be configured to control the motor 18 to increase the rotational speed of the rotating magnetic field to a target stirring speed for efficient / effective stirring. If the magnetic coupling becomes uncoupled, the control system 20 may be configured to control the motor 18 to reduce the rotational speed of the rotating magnetic field until the magnetic coupling is re-established. Thereafter the control system 20 may be configured to control the motor 18 to increase the rotational speed again, this time increasing the rotational speed towards a reduced target speed determined based on the maximum rotational speed before the magnetic coupling was lost in the previous rotational acceleration cycle.

It shall be appreciated that the state of the magnetic coupling may be determined by one or more feedback sensors, such as a torque sensor, a hall effect sensor, or a motor current sensor, that are suitable for generating a signal that is indicative of the state of the magnetic coupling.

To give an example, in the embodiment shown in Figure 1 the control system 20 includes a controller 26 and a feedback sensor 28.

In this embodiment, the feedback sensor 28 may be configured to determine the rotational speed of the rotating magnetic field. Accordingly, the feedback sensor 28 may take the form of a hall effect sensor arranged tangentially to the rotating motor arm 22 (or in other embodiments the motor drive shaft 24) so as to detect the frequency that the magnetic poles of the pair of permanent magnets 17a,b pass by a reference point on the housing 14. In this manner, the feedback sensor 28 may produce an oscillating sensor signal with a frequency that corresponds to the rotational speed of the rotating magnetic field.

When the magnetic coupling is established, the feedback sensor 28 will detect a corresponding reduction in the rotational speed of the rotating magnetic field as the rotational resistance (or resistance torque) increases and more power is required to drive the rotation. Similarly, when the magnetic stir bar 4 uncouples from the pair of permanent magnets 17a, b, the feedback sensor 28 will detect a corresponding increase of the rotational speed of the rotating magnetic field as the rotational resistance decreases.

The feedback sensor 28 may therefore detect characteristic changes of the measured rotational speed of the rotating magnetic field, which are indicative of changes in the state of the magnetic coupling. For example, the feedback sensor 28 may detect a characteristic change in the form of a step increase / decrease of the rotational speed or an acceleration / deceleration that is distinguished from ordinary fluctuations in the rotational speed. In this manner, the feedback sensor 28 may therefore output a sensor signal to the controller 26 that is indicative of the state of the magnetic coupling.

The controller 26 may be configured to receive the sensor signal and to generate a control signal for operating the motor 18 based, at least in part, on the sensor signal. For example, the controller 26 may be configured to compare changes in the rotational speed to a respective state change threshold configured to distinguish a change in the state of the magnetic coupling from ordinary fluctuations in the rotational speed. For example, if the measured rotational speed changes by more than a threshold quantity, or above a threshold rate, the controller 26 may determine a change in the state of the magnetic coupling. For example, the threshold may define a change in the measured rotational speed of at least 10%, preferably at least 20%, more preferably at least 30%, and may be at least 40%, 50% or more, to suitably be indicative of a change in the state of the magnetic coupling. It may further be required that, the change occurs between a predetermined number of rotational speed measurements and/or within a predetermined time period, for example, in less than 0.5 second, preferably less than 1 seconds, and maybe less than 2 second, in order for the change in the measured rotational speed to be indicative of a change in the state of the magnetic coupling.

On this basis, the controller 26 may reduce the rotational speed, and/or the torque, of the motor 18 if the sensor signal indicates the uncoupled state. Conversely, the controller 26 may be configured to increase the rotational speed, and/or the torque of the motor 18 -up to a predefined desired speed or torque value -if the sensor signal indicates the coupled state.

For instance, the controller 26 may be configured to generate a control signal in the form of a current signal for controlling the torque of the motor 18 and thereby controlling the rotational speed of the rotating magnetic field. The current signal may be a pulse-width modulated current signal and the controller 26 may be configured to control the width of each pulse to control the torque generated by the motor 18. Accordingly, if the sensor signal indicates the uncoupled state, the controller 26 may reduce the pulse width of the current signal to quickly decelerate the rotation of the magnetic field generated by the one or more magnetic devices 17a, b and re-establish the magnetic coupling. Once the sensor signal indicates that the coupled state has been re-established, the controller 26 may gradually or incrementally increase the pulse width of the current signal to increase the rotational speed, and/or the torque of the motor 18 in order to drive the magnetic stirring bar 4 to a desired speed for stirring of the volume of nail polish.

In various embodiments, the controller 26 may be configured to increase the rotational speed of the rotating magnetic field to a target stirring speed once the magnetic coupling is established. For example, the controller 26 may be configured to increase the pulse width of the command signal until the sensor signal indicates that the rotational speed of the rotating magnetic field is equal to the target speed. Thereafter, the pulse width of the command signal may remain constant to maintain stirring at a desired speed. In embodiments, the controller 26 may be configured to update the target speed if the magnetic connection becomes uncoupled at a rotational speed that is less than the target stirring speed. For example, the controller 26 may reduce the target speed to the maximum rotational speed that preceded the uncoupling. Thus, the magnetic stirring apparatus 2 (e.g. the controller) may include a processor and/or memory that is configured to record and/or store a speed of rotation of the rotating magnetic field with a frequency suitable to provide a record of the speed of rotation preceding an uncoupling event -for example, speed measurements may be taken at any suitable frequency, e.g. between about every 0.4 secs and every 2 seconds. Hence, once the magnetic coupling is re-established, the controller 26 may be configured to increase the rotational speed of the rotating magnetic field to a target stirring speed that the maximum speed that was previously known to allow maintenance of the magnetic coupling. In this manner, efficient / effective stirring can be achieved at a maximum stirring speed below the predefined original target speed.

This example is not intended to be limiting on the invention though and, in other examples, the control system 20 may include one or more feedback sensors configured to determine a signal that is indicative of: the state of the magnetic coupling; the rotational speed of the rotating magnetic field, and/or the magnetic stir bar 4; and/or the resultant torque at the motor shaft 24, motor arm 22 and/or the magnetic stir bar 4. For example, the feedback sensor 28 may include a torque sensor configured to detect the torque at the motor shaft 24. In such embodiments, the torque sensor may detect a characteristic change in the torque measured at the motor shaft 24 when the magnetic stir bar 4 couples to, or decouples from, the pair of permanent magnets 17a,b. The characteristic change in the torque measured by the torque sensor may therefore indicate a change in the state of the magnetic coupling in a similar / corresponding manner to the rotational speed in the embodiments described above. Thus, in any embodiments of the invention in which rotational speed is used as an indication of magnetic coupling, alternatively torque measurements may be used (or any of the other mechanisms for detecting a coupling / uncoupling event as noted elsewhere herein).

As shall become clear in the following description, the magnetic stir bar 4 may take various suitable forms that are compatible with the magnetic stirring apparatus 2 and suitable for conditioning the volume of nail polish. Accordingly, it shall be appreciated that the following aspects and embodiments may be used in conjunction with the magnetic stirring apparatus 2 described in the aspects and embodiments above, but are not otherwise intended to be limiting on the scope of the invention as regards the magnetic stirring apparatus 2 described above.

Figures 3 and 4 illustrate a magnetic stir bar 4 in accordance with an embodiment of the invention. In this example, the magnetic stir bar 4 is generally elongate and extends along a longitudinal axis from a first end 34 to a second end 36.

The magnetic stir bar 4 is suitable for lengthwise insertion into the receptacle 7 and may therefore have a width and/or depth corresponding to the diameter of the bottle neck 9 of the receptacle 7. For context, the magnetic stir bar 4 may therefore have a width (VV) and/or a depth (D) that is less than about 18 mm, less than about 10 mm, less than about 8 mm or less than about 6 mm. In embodiments, the magnetic stir bar 4 may have a width and/or a depth that is between about 3 mm and 12 mm; for example, about 4 mm, about 5 mm or about 6 mm in the smallest (width) dimension. In one preferred embodiment that may be suitable for use in multiple different nail polish bottles, the width of the stir bar is approximately 5.7 mm.

The magnetic stir bar 4 is also configured to rotate, within the receptacle 7, under the stimulation of the rotating magnetic field and may have a length (L), defined between the first and second ends 34, 36, determined by (and less than) the internal diameter of the receptacle 7 (and in the depicted embodiment, the cylindrical body 9). For context, the length of the magnetic stir bar 4 may therefore be less than the diameter of the cylindrical body 9 and may be less than about 20 mm, less than about 18 mm, less than about 16 mm, less than about 14 mm, or less than about 12 mm. Generally the length of the magnetic stir bar 4 is not less than about 8 mm, such as between 10 mm and 20 mm; about 12 mm, about 14 mm, about 16 mm or about 18 mm. In one preferred embodiment that may be suitable for use in multiple different nail polish bottles, the length of the stir bar is approximately 12 mm.

It shall be appreciated that the dimensions of the magnetic stir bar 4 may vary to suit different types of receptacle 7. Nonetheless, a magnetic stir bar 4 having a length of about 12 mm, as well as a width (W) and/or depth (D) of about 6 mm, or preferably 5.7 mm, is suitable for insertion into most conventional nail polish bottles and remains large enough to provide suitable stirring.

The magnetic stir bar 4 includes a magnetic element 30 configured to generate the second magnetic field, described previously, and a shell 32 that encases the magnetic element 30. The magnetic element 30 may therefore include one or more permanent magnets configured to generate the second magnetic field. For the sake of clarity, it shall be appreciated that the second magnetic field may be complementary to the first magnetic field and suitable for contributing to the magnetic coupling between the magnetic stir bar 4 and the magnetic stirring apparatus 2. For context, in one non-limiting example, the magnetic element 30 may take the form of an N52 magnet having a diameter of 4 mm and a thickness / length of 5 mm, rated with a magnetic pull force of at least 0.6 kg.

The shell 32 itself is suitably formed of a non-magnetic material and is suitably inert so as not to react with the nail polish. For example, the shell 32 may be formed of, or comprise, at least one of: polytetrafluoroethylene (PTFE), acetal (copolymer), acetal (homocopolymer), polyetheretherketone (PEEK), polypropylene, polyphenylene sulfide (PPS), or Vespel SP1. In this manner, the shell 32 may encase the magnetic element 30 so as to protect the magnetic element 30 from corrosion, or other forms of degradation, that may otherwise occur from mixing with the volume of nail polish.

Furthermore, the shell 32 defines an external shape of the magnetic stir bar 4, through and around which the second magnetic field extends. In embodiments of the invention, the shell 32 may take various shapes extending along the longitudinal axis (between the first and second ends 34, 36). However, in each example, the shell 32 is advantageously shaped so that, around / adjacent the shell 32, the second magnetic field is weakest towards the first and second ends 34, 36 of the magnetic stir bar 4: in other words, the magnetic field strength is stronger around the shell portions adjacent the magnetic element and relatively weak at the ends of the shell that are relatively distant from the magnetic element.

In particular, in embodiments of the invention, the shell 32 includes a central housing portion 38, a first end portion 40 and a second end portion 42. The central housing portion 38 is arranged between the first and second end portions 40, 42 and defines a chamber 44 for housing the magnetic element 30. The first and second end portions 40, 42 extend from opposing ends of the housing portion 38, to respective ends 34, 36 of the magnetic stir bar 4. In this manner, the housing portion 38 suitably encases the magnetic element 30 and the first and second end portions 40, 42 effectively act as magnetic buffers, or guards, that extend from the protective casing to ensure that the strength of the second magnetic field is weaker towards the first and second ends 34, 36 of the magnetic stirring bar 4. As shall become clear, this arrangement reduces the possibility of the magnetic stir bar 4 becoming jammed in the nail polish reservoir in use, and allows for convenient removal of the magnetic stir bar 4 from the narrow bottle neck 9 of a receptacle 7 after use.

For the sake of clarity, the non-limiting example of the magnetic stir bar 4, shown in Figures 3 and 4, shall now be described in more detail.

In this embodiment, the shell 32 is elongate and defines a generally cylindrical shape with tapered conical ends. Accordingly, the housing portion 38 may have a cylindrical shape that extends along the longitudinal axis of the magnetic stirring bar 4 between a first end 46 and an opposing second end 48. Suitably, the chamber 44 may extend between the first and second ends 46, 48 and support the magnetic element 30 in an orientation that aligns the second magnetic field with the length of the shell 32. Thus, the magnetic element 30 may be oriented so that an axis (i.e. a magnetic axis), which extends between opposing magnetic poles of the magnetic element 30, is coaxial with the longitudinal axis of the magnetic stir bar 4. In this manner, the magnetic connection between the magnetic stir bar 4 and the pair of permanent magnets 17a,b may urge the magnetic stir bar 4 into alignment with an axis extending between the pair of permanent magnets 17a, b.

In this example, the first and second end portions 40, 42 of the shell 32 are tapered, rounded, and conical, which aids the removal of the magnetic stir bar 4 from the narrow bottle neck 9, as shall be described. The first end portion 40 extends from the first end 46 of the housing portion 38 to the first end 34 of the magnetic stir bar 4 and the second end portion 42 extends from the second end 48 of the housing portion 38 to the second end 36 of the magnetic stir bar 4.

The first and second end portions 40, 42 may each have a length that, amongst other factors, may depend on the magnetic field strength, and/or the size, of the magnetic element 30. For example, the first and second end portions 40, 42 may therefore extend further away from the opposing ends 46, 48 of the housing portion 38 if the magnetic element 30 produces a relatively strong magnetic field than if the magnetic element 30 produces a relatively weak magnetic field.

In some embodiments, the first and second end portions 40, 42 may extend away from the respective ends 46, 48 of the housing portion 38 to respective points where the magnetic field strength of the second magnetic field is negligible. For example, the magnetic field strength may be negligible such that the magnetic field strength is unable to support the weight of the ball bearings 11 and/or of the magnetic stir bar 4 itself. In this manner, the magnetic stir bar 4 may be considered essentially non-magnetic at the first and second ends 34, 36.

In other embodiments, each of the first and second end portions 40, 42 may extend away from the respective ends 46, 48 of the housing portion 38 to respective points where the magnetic field strength of the second magnetic field is significantly reduced compared to the magnetic field strength around the housing portion 38. For example, extending to a respective point where the magnetic field strength of the second magnetic field is less than about 50% of the magnetic field strength around the housing portion 38, beneficially to a respective point where the magnetic field strength is less than 25% of the magnetic field strength around the housing portion 38, less than 10% or less than 5% of the magnetic field strength around the housing portion 38.

To give an example, the shell 32 may have a thickness of approximately 0.5 mm around the housing portion 38, such that the second magnetic field generated by an example magnetic element 30 provides a magnetic pull force of approximately 1.5 kg adjacent! around the housing portion 38. In which case, each of the first and second end portions 40, 42 may extend away from the respective ends 46, 48 of the housing portion 38 by a distance of approximately 4 mm so that the second magnetic field provides a magnetic pull force of approximately 0.25 kg at each of the first and second ends 34, 36.

It shall be appreciated that the size of the housing portion 38 and the thickness of the shell 32 at the housing portion 38 will correspond to the size, and in turn, the magnetic field strength, of the magnetic element 30.

Accordingly, the first and second end portions 40, 42 may each have a length corresponding to the thickness of the shell 32 at the housing portion 38, as in the example above, or the length (between the opposing ends) of the housing portion 38, to suitably reduce the magnetic field strength. For example, the first and second end portions 40, 42 may each have a length of at least 50%, and preferably at least 75%, of the length of the housing portion 38 and/or the first and second end portions 40, 42 may each have a length that is at least twice as large as, or preferably four times greater than, the thickness of the shell 32 around the housing portion 38.

In other embodiments, the ratio of the magnetic field strength adjacent the housing portion to the magnetic field strength adjacent an end of each opposing end of the magnetic stir bar may be about 2:1, 3:1, 4:1, 5:1, 6:1, 8:1, 10:1, 15:1 or even 20:1.

For context, the first and second end portions 40, 42 may therefore typically have a length of between about 3 mm and 8 mm, between about 3 mm and 7 mm, between about 4 mm and 6 mm or about 5 mm.

In other examples, the shell 32 may take other suitable shapes, such as a bar, a capsule, or a coffin-shape, each having a central housing portion that encases the magnetic element and respective end portions that are shaped to act as magnetic buffers.

In addition, as shown in Figures 3 and 4, the magnetic stir bar 4 may also include a recess 50 that extends from an end 34 of the shell 32 towards the end 46 of the housing 38, e.g. to expose an end of the magnetic element. Such an arrangement can be particularly helpful in aiding extraction of the magnetic stir bar from a nail polish bottle, particularly in conjunction with a stir bar retriever 6 of the invention.

In the depicted embodiment, the recess 50 extends from the first end 34 of the magnetic stirring bar 4 and extends, along the longitudinal axis, through the first end portion 40. The recess 50 is complementary to the magnetic end 13 of the stir bar retriever 6 (see Figure 1) and is beneficially configured / shaped to guide the magnetic end 13 towards the first end 46 of the housing portion 38, where the magnetic field strength is stronger.

In this manner, the magnetic end 13 of the stir bar retriever 6 can be inserted into the recess 50 to form a magnetic connection to the magnetic stir bar 4, thereby allowing the magnetic stir bar 4 to be removed from the receptacle 7.

It shall be appreciated that the recess 50 may take various shapes for this purpose but, in this example, the recess 50 is shaped like a narrow groove that extends diametrically across the first end portion 46, such that a stir bar retriever 6 can be inserted from different sides of the magnetic stir bar 4. The recess 50 may have a span (S), between opposing surfaces, of between 1 mm and 4 mm, for example. In this manner, the recess may be suitable for admitting the magnetic end 13 of the stir bar retriever 6, whilst inhibiting the entrapment of the metallic ball bearings 11, which are suitably too large to enter the recess. The recess 50 may extend across the diameter of the first end portion 46, as shown in this example, so that the magnetic end 13 of the stir bar retriever 6 can be inserted into the recess 50 from a range of inclined angles. The magnetic attraction should be sufficient to urge the magnetic stir bar 4 towards the stir bar retriever 6 and thereby to form an end-to-end, or a side-to-side magnetic connection between the magnetic stir bar 4 and the magnetic end 13 of the retriever 6.

In other embodiments, the recess 50 may define tapered groove surfaces that converge from the first end 34 towards the housing portion 38 (defining a V-shaped groove), so that the recess 50 is largest at the first end 34. The recess 50 may additionally, or alternatively, be suitably shaped to re-orient the magnetic stir bar 4 as the magnetic stir bar 4 is attracted towards the magnetic end 13 of the stir bar retriever 6, in order to form an end-to-end magnetic connection with the stir bar retriever 6. For example, the recess 50 may further include a pair of rounded guide formations, one at each diametric end of the groove, for re-orienting the magnetic stir bar 4 as the magnetic connection forms between the magnetic stir bar 4 and the stir bar retriever 6. This may provide for lengthwise removal of the magnetic stir bar 4 from the receptacle 7.

As shall become clear in the following description, the stir bar retriever 6 may take various suitable forms that are compatible with the magnetic stir bar 4 and suitable for removing the magnetic stir bar 4 from the receptacle 7. Accordingly, it shall be appreciated that the following example is provided for the sake of clarity, but is not intended to be limiting on the scope of the invention.

Figure 5 shows an embodiment of the stir bar retriever 6. The stir bar retriever 6 is suitable for insertion into the receptacle 7, for example through the bottle neck 9, and may take the form of an elongate cylindrical rod, that extends from a first end 52 to a second end 54. For context, the cylindrical rod may have a diameter of less than 6 mm, preferably less than 5 mm, for example, so as to be suitable for insertion through the bottle neck 9.

At the first end 52, the stir bar retriever 6 may feature a permanent magnet 53 and a bar of ferrous material 55 that is magnetised by the permanent magnet to form the magnetic end 13. The bar 55 is suitable for insertion into the recess 50 of the magnetic stir bar 4 and may define a narrow contact face 56 at the first end 52 that is suitable for engaging the housing portion 38 to form a magnetic connection to the magnetic stir bar 4.

A method 100 of operating the nail polish condition system 1 to condition a volume of nail polish shall now be described with additional reference to Figures 6 to 9, wherein Figure 6 illustrates an exemplary embodiment of the method 100 and Figures 7 to 9 illustrate the various steps of the method 100.

Initially, in step 102, the receptacle 7 may be received into the docking region 17 of the platform 16 of the magnetic stirring apparatus 2, the lid 10 of the receptacle may be removed and the magnetic stir bar 4 may be inserted, through the bottle neck 9, into a volume of nail polish retained inside the receptacle 7. Once inside the receptacle 7, the magnetic stir bar 4 may magnetically attract the ball bearings 11 towards the magnetic stir bar 4 and against the external surfaces of the shell 32. In particular, the magnetic ball bearings 11 may be attracted towards the cylindrical sides of the central housing portion 38, where the second magnetic field is strongest.

At this time, the control system 20 may control the motor 18 to rotate the pair of permanent magnets 17a,b at a first speed, such as an idle speed, that is suitable for forming the magnetic coupling between the magnetic stir bar 4 and the pair of permanent magnets 17a,b. For example, the controller 26 may generate a command signal in the form of a pulse-width modulated current signal that is output to the motor 18 and configured to cause the pair of permanents magnets 17a,b to rotate at the idle speed.

In this manner, the magnetic stirring apparatus 2 generates the rotating magnetic field.

In step 104, the first and second magnetic fields may interact to attract the magnetic stir bar 4 towards the base of the receptacle 7 and to form the magnetic coupling, as shown in Figure 7. Once formed, the magnetic coupling causes a reduction in the rotational speed of the pair of permanent magnets 17a,b and, hence, the rotating magnetic field.

In step 106, the control system 20 may therefore receive a signal that is indicative that the state of the magnetic coupling has changed to a coupled state.

For example, the reduction in the rotational speed of the rotating magnetic field may be detected by the feedback sensor 28 and output in a sensor signal to the controller 26. The controller 26 may receive the sensor signal and compare the reduction of the rotational speed to the state change threshold. If the reduction in rotational speed exceeds the state change threshold, for example, if the sensor signal indicates that the rotational speed has reduced by more than 25%, the controller 26 may determine that the magnetic coupling has formed.

In step 108, in response to determining the magnetically coupled state, the control system 20 may control the motor 18 to increase the rotational speed of the rotating magnetic field and thereby cause the magnetic stir bar 4 to rotate inside the volume of nail polish at a faster rate, as shown in Figure 8.

For example, the controller 26, may be configured to gradually (and incrementally) increase the pulse width of the command signal output to the motor 18. This has the effect of increasing the rotational speed of the rotating magnetic field and, in turn, rotating the magnetic stir bar 4 at a faster rate.

As the magnetic stir bar 4 rotates, the volume of nail polish is stirred, with mixing commencing near the base of the receptacle 7 and rapidly travelling upward toward the bottle neck 9. Mixing is helped by the movement of the magnetic ball bearings 11, which rotate about the motor axis with the magnetic stir bar 4, as shown in Figure 8. In this manner, the uppermost surface of the volume of nail polish is stirred almost instantaneously.

In embodiments, the control system 20 may be configured to continue increasing the rotational speed of the rotating magnetic field until the rotational speed reaches a target stirring speed that is suitable for efficient stirring of the volume of nail polish. For example, the controller 26 may increase the pulse width in regular increments, for example 5% increments, until the feedback sensor 28 indicates that the target stirring speed has been reached. The controller 26 may, for example, control the motor 18 in a closed-loop feedback system, controlling the pulse width based, at least in part, on the measured rotational speed indicated by the feedback sensor 28.

However, as the rotational speed of the magnetic stir bar 4 increases, the rotational resistance, acting on the magnetic stir bar 4 increases.

Accordingly, in step 110, the rotational resistance may become too large and cause the magnetic stir bar 4 to decouple from the magnetic stirring apparatus 2, as shown in Figure 9. For example, the viscous torque acting on the magnetic stir bar 4 may become too large and the torque threshold of the magnetic coupling may be exceeded, causing the magnetic stir bar 4 to decouple from the pair of permanent magnets 17a,b.

The decoupling causes a sudden increase in the rotational speed of the pair of permanent magnets 17a,b as the magnetic connection is broken and the rotational resistance torque is no longer transferred to the motor shaft 24.

Hence, in step 112, the control system 20 may receive a signal that is indicative that the state of the magnetic coupling has changed to an uncoupled state.

For example, the increase in the rotational speed of the rotating magnetic field may be detected by the feedback sensor 28 and output in a sensor signal to the controller 26.

Again, the controller 26 may receive the sensor signal and compare the increase of the rotational speed to the state change threshold. If the increase in rotational speed exceeds the state change threshold, for example if the sensor signal indicates that the rotational speed has increased by more than 25%, the controller 26 may determine that the magnetic coupling has been lost.

In step 112, the controller 26 may also update the target stirring speed to correspond to the rotational speed of the rotating magnetic field that preceded the uncoupling (e.g. as determined at a predefined time interval earlier, such as 0.1 secs or 1 sec before the uncoupling).

In step 114, in response to determining the magnetically uncoupled state, the control system 20 may control the motor 18 to rapidly reduce the rotational speed of the rotating magnetic field towards the idle speed. For example, the controller 26 may be configured to instantly reduce the pulse width of the command signal output to the motor 18 to the pulse width corresponding to the idle speed. In some circumstances, the rotational speed of the rotating magnetic field may even be reduced to zero, for example.

As the rotational speed of the rotating magnetic field reduces, the magnetic connection between the magnetic stir bar 4 and the pair of permanent magnets 17a,b may be re-established, in step 116, and the control system 20 may receive a signal that is indicative that the state of the magnetic coupling has changed to a coupled state, substantially as described in step 106.

In this circumstance, the control system 20 may then proceed to control the motor 18 to increase the rotational speed of the rotating magnetic field once again, substantially as described in step 108.

However, in this instance, the control system 20 may then increase the rotational speed of the rotating magnetic field (incrementally) to the updated target stirring speed and, on this occasion, the rotational resistance is expected to remain small enough to maintain the magnetic coupling and thereby cause the magnetic stir bar 4 to effectively stir the volume of nail polish at the updated target stirring speed.

Since the viscosity of the nail polish at the base of the reservoir (i.e. at the height of the magnetic stir bar 4) may be expected to reduce as the nail polish is stirred and mixing becomes more complete, in some embodiments, the control system 20 may once again start to increase the rotational speed of the rotating magnetic field to above the speed of the updated target stirring speed, provided that magnetic coupling between the magnetic stir bar 4 and the rotating magnetic field has been maintained at the updated target speed for longer than a threshold period of time. In this manner, the control system 20 may determine a new target stirring speed, for example, about 5% faster than the current rotational speed, and may continue to increase the rotational speed in e.g. 5% increments, until the magnetic coupling fails, substantially as described in steps 108 to 110, or until the first target stirring speed is reached.

Once, the volume of nail polish has been suitably conditioned, the motor 18 may be stopped in step 118. The control system 20 may be configured to rotate the magnetic stir bar 4 for a predetermined period of stirring time before stopping the motor 18.

Typically, 5 minutes of stirring time is sufficient to suitably condition the volume of nail polish at the predefined target stirring speed.

At the end of step 116, the volume of nail polish may be suitably conditioned, for example, providing a homogenous fluid with hardened nail polish suitably softened and mixed to restore the nail polish to a desirable condition. As will be appreciated, in some embodiments the magnetic stir bar 4 does not decouple from the rotating magnetic field and so steps 110 to 116 may not be present.

Thereafter, the magnetic stir bar 4 may be removed from the receptacle 7 using the stir bar retriever 6, as shall now be described in more detail with reference to Figures 10 to 14.

As shown in Figure 10, the first end 52 of the stir-bar retriever 6 may be inserted into the receptacle 7 through the bottle neck 9. The stir bar retriever 6 may then be moved towards the magnetic stir bar 4 and the magnetic end 13 of the stir bar retriever 6 may be inserted into the recess 50 at the first end 34 of the magnetic stir bar 4, as shown in Figure 11. The recess 50 guides the magnetic end 13, through the first end portion 40 of the shell 32, towards the housing portion 38, where the magnetic field strength of the second magnetic field is stronger. Hence, as the magnetic end 13 approaches the housing portion 38, the magnetic stir bar 4 is attracted towards the stir bar retriever 6, forming a magnetic connection therewith.

As shown in Figure 11, the magnetic end 13 may form a side-to-side connection with the magnetic stir bar 4, such that the magnetic stir bar 4 extends orthogonally to the magnetic end 13 of the stir bar retriever 6. However, the opening of the bottle neck 9 may only be large enough for lengthwise removal of the magnetic stir bar 4. Hence, as the stir bar retriever 6 is withdrawn further through the bottle neck 9, the magnetic stir bar 4 may bear against the sides of the receptacle 7 at the bottle neck 9.

Advantageously, in this example, the recess 50 takes the form of a diametric groove and, as shown in Figure 12, the recess 50 is configured to allow the magnetic stir bar 4 to rotate about the magnetic end 13 of the stir bar retriever 6, as the stir bar retriever 6 is withdrawn up through the bottle neck 9. In this manner, the magnetic stir bar 4 forms an end-to-end connection with the stir bar retriever 6, as shown in Figure 13, allowing for lengthwise removal of the magnetic stir bar 4 from the receptacle 7.

As illustrated, the ball bearings 11 may remain attached to the housing portion 38 of the magnetic stir bar 4 due to the magnetic attraction of the second magnetic field, as the magnetic stir bar 4 is being removed. Ordinarily, the attachment of the ball bearings 11 to the magnetic stir bar 4 may cause the magnetic stir bar 4 to become wedged, or jammed, in the bottle neck 9, inhibiting further removal.

However, in these embodiments, as shown in Figure 13, the internal width of the bottle neck 9 in combination with the size of the ball bearings, the structure of the magnetic stir bar 4 and the orientation of the magnetic stir bar 4 as the magnetic stir bar 4 is gradually retracted through the bottle neck 9, ensures that the ball bearings 11 are guided down the sides of the magnetic stir bar 4 towards the second end portion 42. As the ball bearings 11 are guided away from the housing portion 38 along the second end portion 42 towards the second end 36, the magnetic field strength holding the ball bearings 11 against the sides of the magnetic stir bar 4 reduces until, towards the second end 42, the magnetic field strength is no longer strong enough to hold the ball bearings. The magnetic field strength may, for example, be negligible at the second end 36. Hence, as the ball bearings 11 move towards the second end 36 of the magnetic stir bar 4, the force of magnetic attraction either reduces to the extent that the magnetic forces are unable to support the weight of the ball bearings 11, such that the ball bearings 11 detach from the surface of the magnetic stir bar 4, and fall back into the volume of nail polish. Alternatively, the ball bearings 11 may be removed from the nail polish receptacle 7 attached to the tip of the second end 36 of the magnetic stir bar 4 if the magnetic field strength at the second end 36 remains strong enough to support the weight of the ball bearings 11.

Once the magnetic stir bar 4 has been removed from the bottle neck 9 and the ball bearings 11 returned to the receptacle 7, the nail polish is once again ready for storage or for further use, as the case may be, as shown in Figure 14. The magnetic stir bar 4 may then be cleaned and eventually reused to condition other volumes of nail polish.

It will be appreciated that various changes and modifications can be made to the present invention without departing from the spirit and scope of the present application.

In an example, the magnetic stirring apparatus 2 may further include means for indicating that the magnetic coupling is in a coupled state and/or that the magnetic stir bar 4 is rotating inside the receptacle 7. Any suitable indicator device (audible, visual) may be used for signalling a state of the magnetic stirring apparatus 2. For example, the coupled state may be indicated by a suitable noise signal from a speaker of the magnetic stirring apparatus 2 or by a suitable light signal from a light source of the magnetic stirring apparatus 2. Such indications may, for example, be controlled in dependence on the control system 20 receiving the signal that is indicative of the coupled state, which may be received from the feedback sensor 28, as described previously.

Figure 15 shows a cut-away view of an embodiment of the magnetic stirring apparatus 2 that includes a light source for indicating operating modes of the apparatus, such as when a magnetic stir bar is in the coupled state. The magnetic stirring apparatus 2 may be substantially as described in the previous embodiments. However, in this embodiment, the magnetic stirring apparatus 2 further includes a plurality of light sources 60 arranged about the apparatus.

The plurality of light sources 60 may, for example, take the form of a group of LEDs; and the plurality of light sources 60 may particularly be arranged in a ring beneath the platform 16 and the motor arm 22, as shown in Figure 15. The plurality of light sources may be directed towards the platform 16 and, in this example, the platform 16 may be translucent or transparent so as to allow the plurality of light sources 60 to output light there through. For example, the platform 16 may be formed of a clear or frosted plastic or glass. In this manner, the platform 16 may, for example, act as an optic ring that focuses the light passing through towards the receptacle 7.

In this example, the motor arm 22 may be substantially as described previously However, the motor arm 22 may further include a pair of protruding formations 62 that extend radially beyond the pair of permanent magnets 17a,b so as to pass over the plurality of light sources 60 as the motor arm 22 rotates, as shown in Figure 15.

In this manner, as the motor arm 22 rotates, the pair of protruding formations 62 may pass over successive ones of the plurality of light sources 60, temporarily obscuring the light output from those light sources 60, to produce a visual effect of a rotating shadow (or a rotating sequence of lights) through the translucent or transparent platform 16 of the apparatus 2. The shadow may therefore rotate about the motor axis with the pair of permanent magnets 17a,b and indicate the rotation of the pair of permanent magnets 17a,b to an observer looking at the magnetic stirring apparatus 2. In another example, the control system 20 may control the plurality of light sources 60 to indicate the rotation of the pair of permanent magnets 17a,b, for example, by turning successive ones of the plurality of light sources 60 on/off to match the rotation of the pair of permanent magnets 17a, b.

The control system 20 may be substantially as described in the previous embodiments.

However, in this embodiment, the control system 20 may further connect to the plurality of light sources 60, and the control system 20 may be configured to output a control signal for controlling the light output (e.g. the colour or intensity) from the plurality of light sources 60. The control signal may be based, at least in part, on the state of the magnetic coupling between the magnetic stir bar 4 and the pair of permanent magnets 17a,b.

For example, the control system 20 may be configured to receive a signal indicative of the state of the magnetic coupling, substantially as described previously, and if the signal is indicative of the magnetically coupled state, the control system 20 may be configured to output a control signal that causes the plurality of light sources 60 to generate a light signal that is indicative of the magnetic coupling. For example, the control system 20 may control the plurality of light sources 60 to generate a light signal of a particular colour, frequency or in a particular pattern that indicates the existence of magnetic coupling. In embodiments, the control system 20 may output a control signal having the same pulse-width modulated wave as the control signal that is output to the motor 18.

In this manner, the plurality of light sources 60 may pulse for a duration that corresponds to the rotational speed of the rotating magnetic field, i.e. being illuminated with increased brightness for a duration that corresponds to the rotational speed of the rotating magnetic field. Hence, once the magnetic coupling is established, the plurality of light sources 60 may be controlled so as to generate a pulsing light signal with pulses of increasing duration as the rotational speed of the rotating magnetic field increases towards the target stirring speed. At the target stirring speed, the plurality of light sources 60 may generate a pulsing light signal with pulses of constant duration. If the magnetic coupling is lost (uncoupled), the rotational speed of the rotating magnetic field reduces and the plurality of light sources 60 may suddenly generate a pulsing light signal with pulses of very short duration. In this manner, the duration of the pulses of the pulsing light output may be indicative of the state of the magnetic coupling.

The control system 20 may, for example, also include a human machine interface (not shown), such as a control button, for allowing a user to select a colour, colour range, or sequence of the light output from one or more of the plurality of light sources 60.

In another example, the magnetic stirring apparatus 2 may further include a system for recognising or sensing the (type of) receptacle 7. For example, the control system 20 may further include a radio frequency identification device (RFID) configured to communicate with a corresponding radio frequency identification device (RFID) or tag fitted to the receptacle 7. In this manner, the control system 20 may be configured to connect to the receptacle 7 and thereby receive information about the receptacle 7 and/or the nail polish contained in the receptacle 7. Such systems may be particularly beneficial for monitoring of, reporting and controlling the use of counterfeit nail polishes, which may not have an equivalent identification mark.

The control system 20 may further include a weight sensing device, connected to the platform 16 and/or docking region 19, that may be configured to measure the weight of the receptacle 7 and thereby determine the volume of nail polish retained inside the receptacle 7. In this manner, the control system 20 may be configured to produce a record of usage of the nail polish.

In embodiments, the control system 20 may also include a communication module configured to connect to an external system or device. For example, the communication module may include a wireless communication module connectable to a mobile phone.

In this manner, the control system 20 may be configured to communicate relevant information between the magnetic stirring apparatus 2, an end user, and/or a distributor or manufacturer of the nail polish, for example. In this manner, the nail polish conditioning system 1 may be able to communicate with a user, for example via an application on a mobile phone, and inform the user if: they have a small volume of nail polish remaining in a recognised receptacle 7, as well as manufacturer information about the nail polish in a recognised receptacle 7, including stock information, price information and relevant marketing materials, amongst other information. Similarly, the magnetic stirring apparatus 2 may communicate relevant information to a nail polish manufacturer / distributor, such as the use of the magnetic stirring apparatus 2, the volume of nail polish remaining in a recognised receptacle 7, and/or the record of usage of the nail polish for example.

Further expressions of the inventive concept are set out in each of the following clauses.

1. A magnetic stirring apparatus of a nail polish conditioning system, the stirring apparatus being configured to receive a receptacle for a volume of nail polish with a magnetic stirring bar arranged inside the receptacle; the magnetic stirring apparatus comprising: one or more magnetic devices configured to generate a magnetic field for magnetically coupling the stirring bar to the one or more magnetic devices; a motor configured to rotate the one or more magnetic devices about an axis of rotation and thereby to produce a rotating magnetic field for rotating the magnetically coupled stirring bar inside the receptacle; and a control system for controlling the motor, the control system comprising: a controller configured to control a rotational speed of the motor and thereby to control a rotational speed of the rotating magnetic field; and a sensor arrangement configured to generate a sensor signal indicative of a state of the magnetic coupling; wherein the sensor arrangement is configured to output the sensor signal to the controller and the controller is configured to control the rotational speed of the motor based, at least in part, on the sensor signal.

2. A magnetic stirring apparatus according to clause 1, wherein the sensor signal is indicative of: a rotational speed of the motor;

a rotational speed of the rotating magnetic field;

a motor current demand; a difference between the rotational speed of the motor, or the rotating magnetic field, and the rotational speed of the stirring bar; and/or a torque causing the one or more magnetic devices to rotate about the axis of rotation.

A magnetic stirring apparatus according to clause 2, wherein the sensor signal is indicative of a change in the state of the magnetic coupling in dependence on a change of the sensor signal exceeding a state change threshold. 6. 7. 8. 9.

4. A magnetic stirring apparatus according to any preceding clause, wherein the controller is configured to increase the rotational speed of the motor towards a target stirring speed in dependence on the sensor signal being indicative of a magnetically coupled state.

A magnetic stirring apparatus according to clause 4, wherein the controller is configured to increase the rotational speed of the motor incrementally.

A magnetic stirring apparatus according to clause 4 or clause 5, wherein the controller is configured to increase the target stirring speed from a first target stirring speed to a higher second target stirring speed in dependence on the sensor signal indicating the magnetically coupled state for a threshold period of time whilst the motor rotates at the first target stirring speed.

A magnetic stirring apparatus according to any of clauses 4 to 6, wherein the controller is configured to reduce the target stirring speed in dependence on the sensor signal being indicative of the magnetically uncoupled state.

A magnetic stirring apparatus according to clause 7, wherein the controller is configured to determine the reduced target stirring speed based on the rotational speed of the motor preceding the indication of the magnetically uncoupled state.

A magnetic stirring apparatus according to any preceding clause, wherein the controller is configured to reduce the rotational speed of the motor to an idle speed in dependence on the sensor signal being indicative of a magnetically uncoupled state.

A magnetic stirring apparatus according to clause 9, wherein the controller is configured to control a step reduction of the rotational speed of the motor to the idle speed.

A magnetic stirring apparatus according to clause 9 or clause 10, wherein the idle speed is suitable for magnetically coupling the stirring bar to the one or more magnetic devices. 13 15 18

A magnetic stirring apparatus according to any preceding clause, wherein the controller is configured to generate a pulse-width modulated current signal for controlling the rotational speed of the motor.

A magnetic stirring apparatus according to any preceding clause, wherein the one or more magnetic devices comprises a pair of permanent magnets spaced equidistantly about the axis of rotation.

A magnetic stirring apparatus according to any preceding clause, further comprising an indicator device for indicating the state of the magnetic coupling and/or an operational phase of the magnetic stirring apparatus to a user of the magnetic stirring apparatus, wherein the control system is configured to control the indicator device based, at least in part, on the sensor signal.

A magnetic stirring apparatus according to clause 14, wherein the indicator device comprises one or more light sources configured to generate a light output; and/or one or more sound sources configured to generate an audible output.

A magnetic stirring apparatus according to clause 15, wherein the one or more light sources includes a plurality of light sources arranged in a ring, and wherein the magnetic stirring apparatus further comprises a cover, configured to rotate with the one or more magnetic devices so as to temporarily obscure the light output from successive ones of the plurality of light sources as the one or more magnetic devices rotate.

A magnetic stirring apparatus according to clause 15 or clause 16, wherein the controller is configured to control the one or more light sources to output a light signal based on the state of the magnetic coupling.

A magnetic stirring apparatus according to any of clauses 14 to 17, wherein the controller is configured to control the one or more light sources to output a light signal based on an operational phase of the magnetic stirring apparatus.

19 A magnetic stirring apparatus according to any preceding clause, comprising a docking station for receiving the receptacle, wherein the docking station is shaped so as to be complementary to a base shape of the receptacle.

20 A magnetic stirring apparatus according to clause 19, wherein the docking station is releasably secured to the magnetic stirring apparatus for receiving the receptacle, and wherein the docking station is selected from a plurality of docking stations for receiving respective receptacles.

21 A magnetic stirring apparatus according to any preceding clause, wherein the control system further comprises an anti-counterfeiting sensor for recognising an identification tag on the receptacle.

22 A magnetic stirring apparatus according to clause 21, wherein the anti-counterfeiting sensor comprises at least one of: a radio-frequency identification device; a barcode reader; and/or a QR code reader.

23 A magnetic stirring apparatus according to any preceding clause, wherein the control system further comprises a communication module connectable to an external server to communicate information associated with the receptacle and/or the magnetic stirring apparatus between the control system and the external server.

24 A magnetic stirring apparatus according to clause 23, wherein the communication module is a wireless communication module configured to form a wireless connection to the external server.

25 A magnetic stirring apparatus according to clause 23 or clause 24, wherein the information associated with the receptacle and/or the magnetic stirring apparatus includes at least one of: an identification of a user of the magnetic stirring apparatus; a record of use of the magnetic stirring apparatus; an identification of the receptacle; a type of nail polish inside the receptacle; and/or a volume of nail polish inside the receptacle.

26 A magnetic stirring bar of a nail polish conditioning system, the stirring bar being insertable into a nail polish bottle and rotatable inside the nail polish bottle by a rotating magnetic field to condition a volume of nail polish inside the nail polish bottle.

27 A stirring bar according to clause 26, comprising: a magnetic element configured to produce a magnetic field; and a non-magnetic shell that defines a shape of the stirring bar, the shell comprising: a housing portion that encases the magnetic element; and a first end portion and a second end portion that extend from opposing ends of the housing portion to first and second respective ends of the stirring bar, the first and second end portions being shaped such that the magnetic field around the stirring bar has a lower magnetic field strength at each of the first and second end portions than at the housing portion.

28 A stirring bar according to clause 27, wherein the first and second end portions are shaped so that the magnetic field has a magnetic field strength at each of the first and second ends of the stirring bar that is less than 50% of the magnetic field strength at the housing portion.

29 A stirring bar according to clause 28, wherein the first and second end portions are shaped so that the magnetic field has a magnetic field strength at each of the first and second ends of the stirring bar that is less than 25% of the strength at the housing portion.

A stirring bar according to any of clauses 27 to 29, wherein the first and second end portions are shaped so that the magnetic field has negligible strength at each of the first and second ends of the stirring bar.

31 A stirring bar according to any of clauses 27 to 30, wherein each of the first and second end portions has a length that is at least 50% of a length between the opposing ends of the housing portion.

32 A stirring bar according to clause 31, wherein each of the first and second end portions has a length that is at least 75% of the length between the opposing ends of the housing portion.

33 A stirring bar according to any of clauses 27 to 32, wherein the housing portion is cylindrical and each of the first and second end portions taper away from the cylindrical portion towards a respective one of the first and second ends of the shell.

34. A stirring bar according to clause 33, wherein each of first and second end portions has a rounded conical shape.

A stirring bar according to any of clauses 27 to 34, wherein the shell includes a recess that extends from one of the first and second ends, through the respective end portion, towards the magnetic element.

36 A stirring bar according to clause 35, wherein the recess is configured to receive a magnetic end of a stir bar retriever of the nail polish conditioning system for magnetically attracting the stirring bar to the stir bar retriever.

37 A stirring bar according to clause 36, wherein the recess defines a groove that extends diametrically across that end of the shell so that the stir bar retriever is insertable into the recess from opposing sides of the magnetic stir bar.

38 A stirring bar according to clause 37, wherein the groove tapers inwardly towards the housing portion to guide the magnetic end of the stir bar retriever towards the magnetic element.

39 A stirring bar according to clause 37 or clause 38, wherein the groove includes one or more guiding formations for guiding the magnetic end of the stir bar retriever towards the magnetic element.

40. A nail polish conditioning system comprising: 41. 42 44 45

a stirring bar insertable into a receptacle for a volume of nail polish; and a magnetic stirring apparatus configured to receive the receptacle and to generate a rotating magnetic field for rotating the stirring bar inside the receptacle to condition the volume of nail polish.

A nail polish condition system according to clause 40, wherein the stirring bar is a stirring bar according to any of clauses 26 to 39.

A nail polish condition system according to clause 41, further comprising a stir bar retriever including a magnetic end that is insertable into the receptacle for removing the stirring bar.

A nail polish condition system according to clause 42, wherein the stir bar retriever is elongate and cylindrical, with the magnetic end being arranged at one end of the stir bar retriever so as to be insertable into the receptacle whilst the stir bar retriever remains, at least partially, outside the receptacle for removing the stirring bar from the receptacle.

A nail polish condition system according to clause 42 or clause 43, when dependent on clause 36, wherein the magnetic end of the stir bar retriever is complementary to the recess of the stirring bar and insertable into the recess to magnetically attract the stirring bar to the stir bar retriever.

A nail polish condition system according to any of clauses 40 to 44, wherein the magnetic stirring apparatus is a magnetic stirring apparatus according to any of clauses 1 to 25.

Claims

CLAIMSA magnetic stirring apparatus of a nail polish conditioning system, the stirring apparatus being configured to receive a receptacle for a volume of nail polish with a magnetic stirring bar arranged inside the receptacle the magnetic stirring apparatus comprising: one or more magnetic devices configured to generate a magnetic field for magnetically coupling the stirring bar to the one or more magnetic devices; a motor configured to rotate the one or more magnetic devices about an axis of rotation and thereby to produce a rotating magnetic field for rotating the magnetically coupled stirring bar inside the receptacle; and a control system for controlling the motor, the control system comprising: a controller configured to control a rotational speed of the motor and thereby to control a rotational speed of the rotating magnetic field; and a sensor arrangement configured to generate a sensor signal indicative of a state of the magnetic coupling; wherein the sensor arrangement is configured to output the sensor signal to the controller and the controller is configured to control the rotational speed of the motor based, at least in part, on the sensor signal.
2. A magnetic stirring apparatus according to claim 1, wherein the sensor signal is indicative of: a rotational speed of the motor;a rotational speed of the rotating magnetic field;a motor current demand; a difference between the rotational speed of the motor, or the rotating magnetic field, and the rotational speed of the stirring bar; and/or a torque causing the one or more magnetic devices to rotate about the axis of rotation.
3. A magnetic stirring apparatus according to claim 2, wherein the sensor signal is indicative of a change in the state of the magnetic coupling in dependence on a change of the sensor signal exceeding a state change threshold.
4. A magnetic stirring apparatus according to any preceding claim, wherein the controller is configured to increase the rotational speed of the motor towards a target stirring speed in dependence on the sensor signal being indicative of a magnetically coupled state; optionally wherein the controller is configured to increase the rotational speed of the motor incrementally.
5. A magnetic stirring apparatus according to claim 4, wherein the controller is configured to increase the target stirring speed from a first target stirring speed to a higher second target stirring speed in dependence on the sensor signal indicating the magnetically coupled state for a threshold period of time whilst the motor rotates at the first target stirring speed.
6. A magnetic stirring apparatus according to claim 4 or claim 5, wherein the controller is configured to reduce the target stirring speed in dependence on the sensor signal being indicative of the magnetically uncoupled state; optionally wherein the controller is configured to determine the reduced target stirring speed based on the rotational speed of the motor preceding the indication of the magnetically uncoupled state.
7. A magnetic stirring apparatus according to any preceding claim, wherein the controller is configured to reduce the rotational speed of the motor to an idle speed in dependence on the sensor signal being indicative of a magnetically uncoupled state; optionally wherein the controller is configured to control a step reduction of the rotational speed of the motor to the idle speed.
8. A magnetic stirring apparatus according to any preceding claim, wherein the controller is configured to generate a pulse-width modulated current signal for controlling the rotational speed of the motor.
9. A magnetic stirring apparatus according to any preceding claim, wherein the one or more magnetic devices comprises a pair of electromagnets or a pair of permanent magnets spaced equidistantly about the axis of rotation. 10 12
A magnetic stirring apparatus according to any preceding claim, further comprising an indicator device for indicating the state of the magnetic coupling and/or an operational phase of the magnetic stirring apparatus to a user of the magnetic stirring apparatus, wherein the control system is configured to control the indicator device based, at least in part, on the sensor signal.
A magnetic stirring apparatus according to claim 10, wherein the indicator device comprises one or more light sources configured to generate a light output; and/or one or more sound sources configured to generate an audible output.
A magnetic stirring apparatus according to claim 11, wherein the one or more light sources includes a plurality of light sources arranged in a ring, and wherein the magnetic stirring apparatus further comprises a cover, configured to rotate with the one or more magnetic devices so as to temporarily obscure the light output from successive ones of the plurality of light sources as the one or more magnetic devices rotate.
A magnetic stirring apparatus according to claim 11 or claim 12, wherein the controller is configured to control the one or more light sources to output a light signal based on the state of the magnetic coupling and/or based on an operational phase of the magnetic stirring apparatus.
A magnetic stirring apparatus according to any preceding claim, comprising a docking station for receiving the receptacle, wherein the docking station is shaped so as to be complementary to a base shape of the receptacle; optionally wherein the docking station is releasably secured to the magnetic stirring apparatus for receiving the receptacle, and wherein the magnetic stirring apparatus comprises a plurality of docking stations for receiving respective receptacles having a different base shape.
A magnetic stirring apparatus according to any preceding claim, wherein the control system further comprises an anti-counterfeiting sensor for recognising an identification tag on the receptacle; optionally wherein the anti-counterfeiting sensor comprises at least one of: a radio-frequency identification device; a barcode reader; and/or a QR code reader.
16 A magnetic stirring apparatus according to any preceding claim, wherein the control system further comprises a communication module connectable to an external server to communicate information associated with the receptacle and/or the magnetic stirring apparatus between the control system and the external server; optionally wherein the communication module is a wireless communication module configured to form a wireless connection to the external server.
17 A magnetic stirring apparatus according to claim 16, wherein the information associated with the receptacle and/or the magnetic stirring apparatus includes at least one of: an identification of a user of the magnetic stirring apparatus; a record of use of the magnetic stirring apparatus; an identification of the receptacle; a type of nail polish inside the receptacle; and/or a volume of nail polish inside the receptacle.
18 A magnetic stir bar of a nail polish conditioning system, the stir bar being insertable into a nail polish bottle and rotatable inside the nail polish bottle by a rotating magnetic field to condition a volume of nail polish inside the nail polish bottle.
19 A magnetic stir bar according to claim 18, comprising: a magnetic element configured to produce a magnetic field; and a non-magnetic shell that defines a shape of the stirring bar, the shell comprising a housing portion that encases the magnetic element; and a first end portion and a second end portion that extend from opposing ends of the housing portion to first and second respective ends of the stirring bar, the first and second end portions being shaped such that the magnetic field around the stirring bar has a lower magnetic field strength at each of the first and second end portions than at the housing portion.
A magnetic stir bar according to claim 19, wherein the first and second end portions are shaped so that the magnetic field has a magnetic field strength at each of the first and second ends of the stirring bar that is less than 50%, less than 25%, or less than 10% of the magnetic field strength at the housing portion.
21 A magnetic stir bar according to claim 19 or claim 20, wherein each of the first and second end portions has a length that is at least 50% or at least 75% of a length between the opposing ends of the housing portion.
22 A magnetic stir bar according to any of claims 19 to 21, wherein the housing portion is cylindrical and each of the first and second end portions taper away from the cylindrical portion towards a respective one of the first and second ends of the shell; optionally wherein each of first and second end portions has a rounded conical shape.
23 A magnetic stir bar according to any of claims 19 to 22, wherein the shell includes a recess that extends from one of the first and second ends, through the respective end portion, towards the magnetic element; wherein the recess is configured to receive a magnetic end of a stir bar retriever of the nail polish conditioning system for magnetically attracting the stirring bar to the stir bar retriever.
24 A magnetic stir bar according to claim 23, wherein the recess defines a groove that extends diametrically across that end of the shell so that the stir bar retriever is insertable into the recess from opposing sides of the magnetic stir bar; optionally wherein the groove tapers inwardly towards the housing portion to guide the magnetic end of the stir bar retriever towards the magnetic element; and/or wherein the groove includes one or more guiding formations for guiding the magnetic end of the stir bar retriever towards the magnetic element.
25. A nail polish conditioning system comprising: a magnetic stir bar insertable into a receptacle for a volume of nail polish; and a magnetic stirring apparatus configured to receive the receptacle and to generate a rotating magnetic field for rotating the magnetic stir bar inside the receptacle to condition the volume of nail polish; optionally wherein the magnetic stir bar is a magnetic stir bar according to any of claims 18 to 24; and/or wherein the magnetic stirring apparatus is a magnetic stirring apparatus according to any of claims 1 to 17.