A magnetic levitation apparatus

Abstract

A magnetic levitation apparatus includes a movable carriage 1 with a first magnetic array 30 mounted to the carriage. A track 2 comprising a track surface (46, figure 2) and at least one channel 4,6 l

Description

FIELD OF INVENTION

[001] The present disclosure relates to a magnetic levitation apparatus, and in particular and apparatus for levitating and propelling one or more model vehicle above a track. BACKGROUND

[002] Slot track racing sets such as Scalextric® comprise interconnected track sections that form a customisable track circuit. The track sections include shallow channels formed in the track that receive a guide blade located on the lower surface of the model vehicle. The channels are lined with metal rails that carry an electric current that is transferred to the model vehicle via metallic conductors located on the guide blade. The electric current powers a motor on the model car that is used to propel the car around the track. A hand held controller is used to vary the speed of the motor to control the car.

[003] Slot track systems require continuous contact between the vehicle and the track segments in order to maintain motion of the vehicle. Excessive speed can cause the vehicle disconnect and depart the track, particularly when cornering. Furthermore, control of vehicle is limited to variation of the vehicle speed, which limits user control, engagement and entertainment.

[004] It is therefore desirable to provide an improved track racing system for propelling a model vehicle around a preconfigured track. SUMMARY

[005] According to the present disclosure there is provided a magnetic levitation apparatus as described in the accompanying claims.

[006] A magnetic levitation apparatus comprising a movable carriage; a first magnetic element mounted to the carriage; a track comprising a track surface and at least one channel located below the track surface configured to receive the carriage; drive means arranged to propel the carriage within the channel; and a levitation device including a second magnetic element. The levitation device is located above the track surface and the first and second magnetic elements are arranged to levitate the levitation device above the track surface and to magnetically couple the levitation device to the carriage such that movement of the carriage within the channel causes corresponding movement of the levitation device above the track surface. The levitation device may for example be a model vehicle or aircraft. Movement of the carriage in the channel of the track propels the levitation device above the track surface. The carriage is obscured within the channel, and only the levitation device is visible above the track surface, which gives the impression that the device is flying as it is drawn around the track by the carriage. Meanwhile, the carriage is guided and restrained within the channel of the track enabling it to be driven around the track at any speed without the risk of de-railing i.e. departing the track. Moreover, the carriage is physically separated from the levitation object by the upper surface of the track, ensuring the levitation device is not able to collide with or damage the carriage. The "first magnetic element" may incorporate a single magnet, a plurality of magnets, or a plurality or separate magnetic arrays. The magnetic levitation apparatus is preferably a track racing apparatus used for propelling one or more objects around a track.

[007] The direction and / or strength of a magnetic field of the first magnetic element acting upon the levitation device may be varied to control orientation of the levitation device.

[008] The first magnetic element may comprise a first array of magnets arranged to repel the second magnetic element to cause said levitation. The first array of magnets is arranged in an annular array. This creates a magnetic ring with a central magnetic field that repels the second magnetic element. The poles of the first magnetic array are arranged such they are opposite to the facing pole levitation device.

[009] The first array of magnets may be permanent magnets..

[0010] The first magnetic element comprises first and second magnet arrays arranged such that their poles face in an upward direction perpendicular to the base of the carriage.

[0011] The magnetic levitation apparatus may further comprise a second array of magnets arranged to repel the second magnetic element. The second array of magnets are arranged such the poles of the array repel a corresponding same pole of the levitation device.

[0012] The magnetic levitation apparatus may further comprise one or more actuators operative to vary the orientation of one or more magnets of the first magnetic array relative to the levitation device. The one or more actuators re-orientate the one or more magnets of the first magnetic array to change the orientation of the levitation device. This may involve moving one of more magnets independently or moving the entire array.

[0013] The magnetic levitation apparatus may further comprise a controller operative to control the actuators to independently alter the orientation of the each of the magnets of the first magnet array to vary the orientation of the levitation device relative to the upper surface of the track and / or relative to the carriage. The controller may be provided on the carriage or in communication with the carriage. The controller may be operated by a user via input commands provided to a hand held remote control device. Alternatively, one or actuators may be arranged to vary the orientation of the entire first array of magnets relative to the upper track surface to vary the orientation of the levitation device. In this arrangement the magnets may be mounted to a support that is movable relative to the body of the carriage. The one or more actuators are operated to move the support, which may be a support platform, to vary the orientation of the support and hence vary the orientation of the first magnet array. The position of the magnets of the first array relative to each other remains fixed while the orientation of the first array is varied relative to the upper track surface and relative to the levitation device.

[0014] The carriage and levitation device may have a direction of travel defined along the length of the track and the orientation of the magnets of the second magnet array is controlled to vary the pitch and / or roll of the levitation device relative to the direction of travel. Pitch relates to a change in orientation of the device relative to the track across its width and roll is a change in orientation relative to the track lengthwise. Change in pitch may be used to bank the levitation during cornering to counter centrifugal forces that may act to derail the levitation device. The act of varying pitch, roll and or height also provides the user with additional elements of vehicle movement to control, which increases engagement and excitement of the user.

[0015] Each array of magnets may be arranged in a concentric annular arrangement having a radius. The first array of magnets may be arranged radially outwards of the second array of magnets.

[0016] The second array of magnets may be electromagnets. The magnetic field of each electromagnet may be independently controlled to maintain the levitation device in a predetermined position relative to the first magnetic array, which may be central to the array.

[0017] A controller may operate the second magnetic array by independently activating and deactivating the electromagnets to centralise the second magnetic element relative to the first magnetic array.

[0018] The first magnetic array may have an annular form with a central levitation axis arranged perpendicular to the radius of the array.

[0019] The magnetic levitation apparatus may further comprise a magnetic field sensor such as a hall effect sensor operative to detect movement of the levitation device away from the levitation axis. The controller operates the second magnet array to return the levitation device to the levitation axis in response to a signal from the magnetic field sensor. The magnetic field sensor may comprise a plurality of hall effect sensors arrange to detect movement of the levitation device in multiple directions away from the levitation axis.

[0020] The magnetic field sensor may detect direction of movement of the device in multiple directions away from the levitation axis and the electromagnets are operated to compensate and move the device in the opposing direction to re-centre it above the first magnetic array. When the levitation device is accelerating or decelerating it can become unstable, due in part to inertia of motion and centrifugal force effects. The electromagnets may counter this instability by creating a repulsive magnetic force to opposing these forces and re-centre the levitation device. By controlling the orientation or tilt of the magnetic object, these forces can be accommodated.

[0021] The track may comprise a plurality of interconnectable track segments and each track segment comprises a base, an upper wall defining the track surface and upstanding side walls forming an open ended channel with the segments combining to form a continuous channel.

[0022] Each track segment may comprise upper and lower parts that are separable. These parts comprise a base, a lid and upstanding side walls connected to one or both of the base and the lid such the channel is completely encompassed with only the ends open to allow passage of the carriage between segments.

[0023] Each track segment may include one or more channels defined within the track segment for receiving two or more respective carriages and may include one or more inner partition walls separating the two or more channels. A separate levitation device and separate remote control is provided with each carriage and each carriage may be independently controlled.

[0024] Each channel comprises a carriage guide for guiding the carriage along a fixed path within the track in the direction of travel. The guide may be a longitudinally extending slot and the carriage may include a guide member received within the guide slot.

[0025] The levitation device may comprise a body and the second magnetic element is a permanent magnet supported by the body. The magnet may be surrounded and housed within the body. The body has upper and lower surfaces and the magnet is arranged such that the poles extend perpendicular to the upper and lower surfaces.

[0026] The controller is operative to controller the drive means to vary the speed of travel of the carriage and the magnetically coupled levitation device.

[0027] The magnetic levitation apparatus may further comprise a remote controller operative to control the speed of travel of the carriage, and to control at least one of the first and second magnet arrays to vary the height and / or pitch and / or roll of the levitation device.

[0028] The magnetic levitation apparatus may further comprise means for supplying electrical power to the carriage. This may be via a conductive o inductive connection between the track and the carriage. Power supply to the carriage may be controlled a controller.

[0029] The base of the track may define an inner track surface that supports the carriage and the carriage comprises a plurality of wheels that engage with the inner track surface and one or more motors arranged to drive one or more of the wheels.

[0030] The carriage may comprise a secondary transmitting induction coil and the levitation device may comprise a secondary receiving induction coil capable of transmitting power from said carriage to said levitation device to power an electronic element on said levitation device.

[0031] The carriage may comprise at least one visual and / or audio indicator to provide an indication of the position of the carriage within the track.

[0032] Each of the first and second magnetic elements may individually generate a magnetic field, and said individual magnetic fields collectively form a plurality of magnetic fields. The plurality of magnetic fields act upon the levitation device to levitate the levitation device and to hold the levitation device within the levitating magnetic field.

[0033] The carriage may be controlled remotely through wireless control or may be controlled by wired control. Wired control could be enabled by physically transmission of a signal from the segment assembly to the carriage. Remote control of the carriage beneficially removes the need for said physical transmission of a signal between the segment assembly and the carriage, which has the benefit of further enabling the freedom of circuit customisability and reduces physical connection interruptions that may occur if contact between the carriage and segment assembly is interrupted.

[0034] Each wheel may be connected to a driving actuator such as an electric motor, configured to rotate said wheels. This may take the form of a single driving actuator that drives one or more wheels, or multiple driving actuators with each of the multiple driving actuators independently driving one or more wheels.

[0035] The height of the magnetic object relative to the carriage may be controlled by altering the magnetic fields acting upon the magnetic object. The levitation device my therefore be lowered or raised to navigate obstacles that may be present along the track, to again increase interest and enjoyment for the user.

[0036] If an instability is detected, the electromagnets may be deactivated, which cause the levitation device to be pulled into engagement with the track by the permanent magnets to prevent de-railing and avoid damage.

[0037] Electrical power for the carriage may be transmitted from the segment assembly to the carriage. In an aspect of the disclosure, the carriage could comprise conductive elements that form a moving physical connection with power transmission elements provided on the track. This beneficially removes the requirement for the carriage to comprise a power source. Alternatively, the carriage could comprise a receiving driving induction coil and the segment assembly could comprise one or more transmitting driving induction coils. Therefore, there is no need for physical contact between the carriage and the track.

[0038] The levitating device could comprise one or more light sources and / or one or more actuators to enable movement of mechanical elements of the levitating device or one or more noise emitting elements. The levitating device is therefore able to relay audio / visual feedback to a user on the condition of the magnetic object or could beneficially control mechanical elements to enable the device to perform an action.

[0039] The electronic elements could be powered by induction coils. In an aspect of the disclosure the carriage could comprise a secondary transmitting induction coil and the magnetic object could comprise a secondary receiving induction coil. This beneficially would allow the carriage to transmit power to a corresponding magnetic object resulting in a magnetic object with electronic elements not requiring an on-board power source.

[0040] The carriage may comprise a servomotor that is configured to change the orientation of a part of the carriage relative to the track to change the orientation of the first and / or second magnetic arrays. This allows the orientation and positioning of the levitation device to be altered based on the orientation of the movable part of the carriage . BRIEF DESCRIPTION OF THE DRAWINGS

[0041] The present disclosure will now be described by way of example only with reference to the following illustrative figures in which: Figure 1 shows a track section and a carriage according an embodiment of the disclosure; Figure 2 shows a covered track section and levitation device according an embodiment of the disclosure; Figure 3 shows an assembled track and a levitation device according an embodiment of the disclosure; Figure 4 is a cross-sectional schematic representation of a carriage within a track segment with a levitation device held above the track surface in a first levitation position and orientation in accordance with an embodiment of the disclosure; Figure 5 is a cross-sectional schematic representation of a carriage within a track segment with a levitation device held above the track surface in a second lowered levitation position and orientation in accordance with an embodiment of the disclosure; Figure 6 is a cross-sectional schematic representation of a carriage within a track segment with a levitation device held above the track surface in a third raised levitation position and orientation in accordance with an embodiment of the disclosure; Figure 7 is a cross-sectional schematic representation of a carriage within a track segment with a levitation device held above the track surface in a pitched orientation in accordance with an embodiment of the disclosure; Figure 8 is a cross-sectional schematic representation of a carriage within a track segment with a levitation device held above the track surface in a first levitation position and orientation in accordance with an alternative embodiment of the disclosure; Figure 9 is a cross-sectional schematic representation of a carriage within a track segment with a levitation device held above the track surface in a second lowered levitation position and orientation in accordance with an alternative embodiment of the disclosure; Figure 10 is a cross-sectional schematic representation of a carriage within a track segment with a levitation device held above the track surface in a pitched orientation in accordance with an embodiment of the disclosure; and Figure 11 shows a cross-sectional schematic representation of a carriage within a segment assembly in which the levitation device has been drawn into contact with the track in accordance with a further embodiment of the disclosure. DESCRIPTION OF EMBODIMENTS

[0042] The following description presents exemplary embodiments and, together with the drawings, serves to explain principles of the disclosure. The scope of the disclosure is not intended to be limited to the precise details of the embodiments or exact adherence with all method steps. Variations will be apparent to a skilled person and are deemed also to be covered by the description. Terms for features used herein should be given a broad interpretation that also encompasses equivalent functions and features. In some cases, several alternative terms (synonyms) for structural features have been provided but such terms are not intended to be exhaustive.

[0043] Descriptive terms should also be given the broadest possible interpretation; e.g. the term "comprising" as used in this specification means "consisting at least in part of" such that interpreting each statement in this specification that includes the term "comprising", features other than that or those prefaced by the term may also be present. Related terms such as "comprise" and "comprises" are to be interpreted in the same manner. Directional terms such as "vertical", "horizontal", "up", "down", "upper" and "lower" are relative terms that may be used for convenience of explanation usually with reference to the illustrations and are not intended to be ultimately limiting if an equivalent function can be achieved with an alternative dimension and / or direction.

[0044] The description herein refers to embodiments with particular combinations of configuration steps or features. However, it is envisaged that further combinations and cross-combinations of compatible steps or features between embodiments will be possible. The description of multiple features in relation to any specific embodiment is not an indication that such features are inextricably linked, and isolated features may function independently from other features and not necessarily require implementation as a complete combination.

[0045] Referring to Figure 1, a carriage 1 is located within a first track section 2 of a track segment. The term 'carriage' means any movable object configured to carry or support other elements. The first track section 2 comprises a first channel section 4 and a second channel section 6. The first channel section 4 includes a base 8a, outer side wall 10 and an inner side wall 12 upstanding from the base 8a. The second channel section 6 includes a base 8b, outer side wall 15 and an inner side wall 12 that is common with the inner side wall of the first track section 4. The first and second channel sections 4,6 are arranged in a side-by-side configuration such that the channels seconds 4,6 are substantially parallel to one another along their lengths.

[0046] Each channel section 4,6 includes an open-ended shallow guide slot 14 running along the length of the channel section 4,6. The guide slot 14 is located centrally across the width of each channel section 4,6, although other configurations may be provided. Conductive rails 16 are arranged either side of guide slots 3, which form power transmission elements 4. The conductive rails 16 include connection tabs at one end and connection sockets at the opposing end for connecting the connection to connection sockets and connection tabs of further track segments respectively. Each guide slot 14 is configured to receive a corresponding guide member of the carriage 1 to guide the carriage 1 along the track and retain the carriage 1 centrally within the respective channel section 4,6, as will be described in further detail below.

[0047] The first track section 4 includes hinged assembly clips 20 located at a first end of the respective outer side walls 10,15. Corresponding connectors 22 are located at the opposing end of the respective outer side wall 10,15. The assembly clips 20 and connectors 22 are arranged such that when a first track segment is brought into end-on-end abutment with a second track segment, the hinged assembly clips 20 of the first track section 2 of the first track segment clip to the connectors 22 of the second track segment to secure the two track segments together. Similarly, a third track segment may be connected to the opposing end of the first track segment by connecting the hinged assembly clips 20 of the third track segment to the connectors 22 of the first track segment. In this way, a series of track segments of differing geometries (e.g. straight segments and curved segments) may be connected together to form a continuous circuit. The first track section 2 further includes a pair of connector portions 21 along each outer side wall 10,15, each including a ridge for securing a corresponding connector of a lid section, as described below.

[0048] The carriage 1 comprises a base 24 defining the carriage body. The base 24 has a longitudinal axis that in use aligns with the length of the track section 2. A plurality of wheels 26 is rotationally mounted to the base 24. Each wheel has an axis of rotation arranged perpendicular to the longitudinal axis and is located at an outer edge of the base 24 such that they run on the base 8 of the track section 2. A pair of electric motors 28A, 28B are mounted at the front end of carriage 1. The motors 28A,28B are connected to front wheels 26A,26B respectively, with the wheels 26A,26B being rotationally mounted to the base 24 via the motors 26A,26B. The wheels 26A,26B are arranged to transform torque from the motors 28A,28B into tractive force from the tires to the track to move the carriage in a forward or reverse direction along the track 8 depending on the direction of rotation of the motors 28A,28B. The carriage 1 may be configured as either front-wheel drive, or rear-wheel drive. Alternatively, the carriage may include a single motor connected to the wheels 26 via a drive chain. As a further alternatively, the carriage may be all-wheel drive and include a dedicated motor connected to each of the wheels 26. In other embodiments each wheel 26 may include a dedicated motor 28. Each motor 28 is an electric motor and the speed of the motors 28 may be adjusted by changing the voltage input, or via pulse-width modulation. The width of the base 24 and axial spacing of the wheels is selected such that the carriage fits within the channel defined by the side walls 10,12 with minimal clearance between the carriage and the side walls 10,12.

[0049] A guide 23 is mounted to the lower surface of the base 24. The guide is rotatable and includes a guide blade that located within the guide slot 14 of the track base 8. Similar guides are known in the prior art for use with track cars. Electrical contacts 25 are provided on the lower surface of the base 24 in the form of brushes, plates or braids that are arranged to contact the conductive rails 16 of the track 8 when the guide is located within the slot. The electrical contacts 25 are electrically connected to the motors 28A,28B to provide current to the motors from the conductive rails 16 to power the motors 28A,28B. Alternatively, the carriage 1 may comprise an integrated power source to provide electrical power to the carriage 1 or the carriage could comprise a receiving induction coil to receive power from a transmitting induction coil located on or near the track.

[0050] A magnetic array 30 is mounted on the upper surface of the base 24 of the carriage 1 substantially centrally. The magnetic array 30 includes a first array of electromagnets 32 and a second array of permanent magnets 34. Four electromagnets 32 are arranged centrally within the array in an equally spaced annular arrangement. Four permanent magnets 34 are arranged in equally spaced annular arrangement around and radially outwards of the centrally arranged electromagnets 32. A plurality of servomotors 36 are mounted to the base 24. Each servomotor 36 is connected to a corresponding permanent magnet 34. Each servomotor has a shaft to which the respective permanent magnet 34 is mounted. The permanent magnets 34 may be mounted directly to the shaft or via alternative means. Each permanent magnet 34 is independently rotatable by the respective servomotor 36. The shaft of each servomotor 36 is arranged having an axis of rotation parallel to the upper surface of the base 24. In other embodiments, alternative rotary or linear actuators may be used to move the permanent magnets 34. The axis of rotation of each permanent magnets 34 is substantially tangential to the central array of electromagnetic 32. A plurality of hall effect sensors 39 are arranged centrally within the magnetic array 30. A levitation object 38 is magnetically coupled to the magnetic array 30, and levitated above the magnetic array 30 as described in further detail below.

[0051] Figure 2 shows a complete track segment 40, which includes a second track section 42 that forms a lid covering the first track section 2. The first track section 2 and second track section 42 are assembled to form the complete track segment 40. The lid 42 has upper surface 46 that defines the surface of the track above which the levitation object 38 is propelled. The lower surface of the lid 42 closes the channels 4,6, such that the channels 4,6 are completely encompassed in a first plane perpendicular to the length of the track. The channels 4,6 remain open ended when the lid 42 is applied. The lid section 42 includes hinged clips 44 that engage with the connectors 21 of the first track section 2 to secure the two parts together. The base 8, outer side walls 10,15, and lid 42 enclosure the channel sections 4,6 such that the carriage 1 is hidden within the track segment 40. The channels 4,6 are open at each end such that the combined track segments 40 form continuous channels 4,6 within the carriage 1 travels between track segments 40. The height of the channels 4,6, as defined by the height of the side walls 10,15 is selected such that the spacing between the uppermost surface of the carriage 11 and the innersurface of the lid 42 is less than the depth of the guide, such the lid vertically restrains the carriage and prevents the carriage rising to a distance where the guide is able to leave the guide slot. The track may be operated with a single carriage 1 within one of the channels 4,6 and a single corresponding levitation object 38, or may be operated with a carriage 1 within each channel 4,6 and two levitation objects 38 for racing.

[0052] The levitation object 38 is located outside the track segment 40 and levitates at a location spaced above the upper surface 46 of the lid 42 at a position corresponding to the location of the carriage 1 within the track segment 40. The levitation object 38 is magnetically coupled from outside the track segment 40 to the magnetic array 30 of the carriage 1 within the track segment 40. Obscuring the carriage 1 from view within the segment creates a visual illusion that the levitation object 38 is self-levitating above the track segment 40 and when the carriage 1 is moving, that the levitation object 38 is self-propelled. The levitating object 38 may be formed as a car, a flying vehicle, a character figure, or any other desired shape.

[0053] Referring to Figure 3, a circuit 48 is formed of a plurality of track segments 40. Track segments 40 of differing geometries may be combined to form different customised circuits 48. Movement of the levitation object 38 around the track circuit 48 is controlled by movement of the corresponding carriage 1 within the track circuit 48. Movement of the carriage 1 is controlled by varying the current delivered to the carriage 1 via the conductive rails 16, which are connected to a power supply. The track circuit 48 may include an electrical control module configured to selectively vary the current to each channel 4,6. The electrical control module is controlled by the user via a hand held remote controller that is operatively connected to the control module. The remote controller may comprise a wired connection, or wireless transmitter and may include integrated potentiometers, or joysticks, or other adjustable voltage dividers to operate and adjust the speed or the levitation object 38. The controller may also be used to control the height, pitch and / or roll of the levitation object 38 by controlling, via the control module, the field strength of the electromagnets 32 and / or the orientation of the permanent magnets 34 through operation of the servo motors 36.

[0054] Referring to Figure 4, the carriage 1 is located within the channel 4 of the track segment 40 with minimal vertical clearance between the carriage 1 and the lid 42. The guide 23 is located with the slot 14, which laterally restrains the carriage 1 centrally within the channel 4. The guide element 23 includes a wheel that engages the side walls of the slot 14, which alternatively may be a bearing and / or any other suitable guide member. The electrical contacts 25 are in contact with the conductive rails 16 such that electrical power is able to be transferred to the motors 28.

[0055] The carriage 1 includes a light element 50, such as an LED, located at the uppermost surface adjacent the lid 42. The light element 50 and the lid material and lid thickness are selected such that light element is visible through the lid 42, to provide a visually indication of the carriage 1 within the track. Beneficially, when attached to the carriage, the second segment 2 could be configured so that the indicators 18 are visible through the second segment 2. In addition, or alternatively, and audio device may be provided on the carriage to give an audio indication of the carriage position and / or provide entertaining sounds effects corresponding to the levitation.

[0056] A permanent magnet 52, or plurality or permanent magnets, is located within the levitation object 38. The levitation object 38 may further comprise electronic elements (not shown), such as LEDs, noise emitting elements, or actuators configured to actuate mechanical elements. Power could be transmitted to these electronic elements via inductive coupling. A transmitting inductive coil could be mounted to the carriage 1 and a receiving inductive coil could be mounted to the magnetic object. The poles of the permanent magnet 52 are arranged in vertically opposite directions in use, with a first pole 54 facing the track and a second pole 56 facing away from the track. The electromagnets 32 are configured and arranged such that the upwardly directed pole of the electromagnets 32 opposes the first pole 54 of the levitation object. In the illustrated embodiment the first pole 54 of the levitation device 38 is the south pole of the permanent magnet 52.

[0057] The permanent magnets 34 provide the repulsion force to levitate the levitation device 38. The permanent magnets 34 are also used to control the pitch and roll of the levitation object 38. The permanent magnets 34 are arranged with their north poles facing upwardly towards the opposing south poles of the levitation device 38. The annular form of the array 34 of permanent magnets effectively forms a ring magnet. The arrangement of the magnetic field lines at the centre of the array 34 acts to repel the levitation device 38 when it is concentrically arranged above the array 34. However, if the levitation device 38 deviates from the centre the opposing poles of the levitation device 38 and the permanent magnets 34 attract each other and the levitation device is drawn towards the track. To maintain levitation, the levitation device must be held centrally within the permanent magnet array 34 on a central levitation axis. Stabilisation is therefore required to centralise the levitation device 38 and maintain levitation, particularly during motion around the track.

[0058] The electromagnet array 32 and permanent magnet array 34 are concentrically arranged. The electromagnet array 32 is configured such that the south poles are upwardly directed towards the levitation device 38 to repel the like south pole of the levitation device. The array of electromagnets 32 are arranged radially outwards of the central levitation axis. A controller is configured to selectively turn the electromagnets on and off independently. The plurality of hall sensors 39 are located centrally within the magnetic array 30. A first hall sensor determines the presence of the levitation device 38 above the array 30. A second hall sensor senses movement of the levitation device along a first lateral axis perpendicular to the levitation axis. A third hall sensor senses movement of the levitation device along a second lateral axis perpendicular to the levitation axis and perpendicular to the first lateral axis. The second and third hall sensors are therefore able to sense movement of the levitation device as it deviates from the levitation axis and a signal from the hall sensor is provide to the controller which determines the direction of travel of the levitation device. In response to the levitation device 38 moving away from the levitation axis, an electromagnet located along the direction of travel is rapidly activated by the controller in response to the hall sensor signal to repel the levitation device in the reverse direction towards the levitation axis. The electromagnetic is then immediately deactivated. If the force applied by the electromagnet overcorrects, the diametrically opposing electromagnetic is activated to correct I the return direction. This process of continuous activation and deactivation of the electromagnet array 32 laterally stabilises the levitation device 38 and centralises it within the magnetic array 30 thereby maintaining levitation.

[0059] Each permanent magnet 34 is also independently rotatable relative to the levitation object 38 to vary the orientation of the poles and therefore vary the magnetic field acting on the levitation object 38. In the arrangement of Figure 4, the permanent magnets 32 are oriented symmetrically with the upper surface of each magnet parallel to the lower surface of the levitation object 38 and the track. In this arrangement each permanent magnet acts equally on the levitation object 38 and the levitation object 38 is level and parallel to the track in roll and pitch.

[0060] Referring to Figure 5, in a second mode of operation, at least the two permanent magnets 32 shown have been rotated using the servo motors 36 to a position in which the upper surface of each permanent magnet 34 is angled inwardly towards the centre of the magnetic array, and towards the levitation object 38. As a result, the strength of the magnetic field of each permanent magnet 34 is increased. This has the effect of pulling the levitation object 38 closer to the carriage 1 and decreasing its height relative to the track. As such, the height of the levitation object 38 is varied without varying the magnetic field strength of the electromagnets 34.

[0061] Referring to Figure 6, in a third mode of operation, the at least two permanent magnets 32 have been rotated using the servo motors 36 to a position in which the upper surface of each permanent magnet 34 is angled outwardly away from the centre of the magnetic array, and away the levitation object 38. As a result, the strength of the magnetic field of each permanent magnet 34 acting on the levitation object 38 is decreased. This has the effect of allowing the levitation object 38 to move further from the carriage 1 and increasing its height relative to the track.

[0062] Referring to Figure 7, in a fourth mode of operation, the at least two permanent magnets 34 shown are angled in the same direction. At least one of the permanent magnets 34 has been rotated such that its upper surface is angled towards the centre of the carriage and towards the levitation object 38. At the same time the at least one other permanent magnet 34 has been rotated such that its upper surface is angled away from the centre of the magnetic array and away from the levitation object 38. As a result, the strength of the magnetic field acting on the levitation object 38 from the permanent magnets 34 is increased on one side and decreased on the other, causing the levitation object 38 to pitch towards the stronger magnetic field into a non-parallel orientation. This variation in pitch is achieved by varying the position of the permanent magnets on opposing sides of the magnetic array in the lateral direction, perpendicular to the length of the track. Varying the pitch of the levitation object 38 in this manner can be used to stabilise the levitation object 38 as it is accelerated around the track. In particular, it enables the levitation object 38 to be banked into corners, enabling corners to be negotiated at greater speed while reducing the risk of the levitation device departing the track. In a similar manner to the pitch control, the roll of the levitation object 38 may be varied by rotating the permanent magnets 34 on opposing sides of the array in the fore and aft direction along the length of the track 2 to tilt the levitation object forwardly or incline the front end.

[0063] In an alternative embodiment the array of permanent magnets may be replaced with a further array of electromagnets, each of which is independently controllable to vary the magnetic field strength. The angle or height of the levitation object 38 may be varied by increasing and decreasing pulse-width modulation or voltage supplied to the electromagnets to vary the magnetic field acting on the levitation object 38. This has benefits to the lifespan of the device by avoiding the mechanical wear issues associated with rotating the permanent magnets with servo motors. However, electromagnets are generally much heavier than permanent magnets and require power to be supplied to them. Further, heat dissipation becomes an issue, and the generated magnetic force can alter when the electromagnets heat up.

[0064] Referring to Figure 8, in an alternative embodiment, the permanent magnets 134 are fixed to a movable platform 122 that is supported on the base 124 of the carriage 100 by a plurality of springs 125. The permanent magnets are fixed to the platform 122 in an array surrounding an inner electromagnet array as described above. Servo motors 136 are arranged on opposing sides of the platform 122 and are mounted on the base 124. The servo motors 136 include arms or 'servo horns' 127 rotatable by the servo motors 136. The servo horns 127 engage the upper surface of the platform 122. Rotation of the servo horns 127 causes the height of the platform 122 to raise or lower at the respective side, with the springs 125 compressing as the platform is lowered and providing a return force to lift the platform when the servo horns 127 are raised. The position of the permanent magnets 134 relative to the levitation object 138 is therefore varied by varying the angle of the platform 122 and hence the permanent magnet array. In the arrangement of Figure 8 the platform is held in a horizontal orientation parallel to the lower surface of the levitation device, which consequently is held horizontal and parallel to the track.

[0065] In Figure 9, the at least two servo motors deflect the platform 122 downwardly equal distances at either side ensuring it remains parallel to the base 124. As a result, the levitation device 138 is lowered towards the track 102 while remaining in a parallel horizontal orientation.

[0066] In Figure 10, one servo motor 136 deflects the platform 122 downwardly at one side, whilst on the opposing side at least one servo motor provides no downward deflection, causing the platform 122 to angle downwards towards the lowered end. The levitation object 138 remains parallel to the magnetic assembly 130 of the platform 124, and hence is angled relative to the track 102.

[0067] Referring to Figure 11, the levitation object 138 becomes unstable when the plurality of electromagnets can no longer maintain the magnetic object in a central position relative to the carriage 100. When the levitation object 138 becomes unstable and moves off centre the magnetic field strength of the permanent magnets overcomes the field strength of eth electromagnets 132. The levitation object 138 is therefore attracted towards the permanent magnets 134, bringing it into engagement with the upper surface of the track segment 40 nearest the underlying permanent magnet. This prevents the levitation object from being propelled away from the track at speed, thereby 5 improving safety and preventing damage to the levitation object 138. The same is the case in the first embodiment described above. This beneficially improves safety for the user. Optionally, when the hall sensors 110 return a signal indicative of the magnetic object becoming unstable, the electromagnets can be disabled, further increasing the safety afforded by the magnetic levitation arrangement. In addition, or alternatively, the 10 control module may cause the carriage to stop when the levitation object 138 has become unstable.

Claims

1. A magnetic levitation apparatus comprising: a movable carriage;5 a first magnetic element mounted to the carriage;a track comprising a track surface and at least one channel located below the track surface configured to receive the carriage;drive means arranged to propel the carriage within the channel;a levitation device including a second magnetic element;10 wherein the levitation device is located above the track surface and thefirst and second magnetic elements are arranged to levitate the levitation device above the track surface and to magnetically couple the levitation device to the U / carriage such that movement of the carriage within the channel causesCMcorresponding movement of the levitation device above the track surface;15 wherein the first magnetic element comprises a first array of magnetsarranged to repel the second magnetic element to cause said levitation, and aCMsecond array of magnets arranged to maintain the second magnetic element in a levitation position above the first array of magnets.20 2. A magnetic levitation apparatus according to claim 1 wherein a levitation axis isdefined through the centre of the first array of magnets and the second array of magnets is arranged to maintain the second magnetic element on the levitation axis.25 3. A magnetic levitation apparatus according to claim 2 further comprising one ormore actuators operative to vary the orientation of one or more magnets of the first magnetic array relative to the track surface.

4. A magnetic levitation apparatus according to claim 2 further comprising athe orientation of each of the magnets of the second magnet array to vary the orientation of the levitation device relative to the upper surface of the track.

5. A magnetic levitation apparatus according to claim 2 further comprising a5 controller operative to control the one or more actuators to vary the orientationof the first array of magnets relative to the upper track surface to vary the orientation of the levitation device.

6. A magnetic levitation apparatus according to claim 5 wherein the first magnetic10 array is mounted on a support that is movable relative to the body of thecarriage and the one or more actuators are arranged to move the support to vary the orientation of the first magnetic array.U J 7. A magnetic levitation apparatus according to any one of claims 3 to 5 wherein CM15 the carriage and levitation device have a direction of travel defined along thelength of the track and the orientation of the magnets of the second magnet _ array is controlled to vary the pitch and / or roll of the levitation device relative toCMthe direction of travel.20 8. A magnetic levitation apparatus according to any one of claims 3 to 7 whereinthe first array of magnets is arranged radially outwards of the second array of magnets.

9. A magnetic levitation apparatus according to any one of claims 1 to 8 wherein25 the second array of magnets are electromagnets.

10. A magnetic levitation apparatus according to claim 9 wherein eachelectromagnet is independently operated by the controller to maintain the levitation device in a predetermined position relative to the first magnetic array.3011. A magnetic levitation apparatus according to claim 10 further comprising at leastone magnetic field sensor operative to detect movement of the levitation deviceaway from the levitation position and wherein the controller operates the electromagnets of the second magnet array to return the levitation device to the levitation position in response to a signal from the magnetic field sensor.5 12. A magnetic levitation apparatus according to any preceding claim wherein thetrack comprises a plurality of interconnectable track segments and each track segment comprises a base, an upper wall defining the track surface and upstanding side walls forming an open ended channel.10 13. A magnetic levitation apparatus according to claim 12 wherein each tracksegment comprises upper and lower parts that are separable.14.15.20A magnetic levitation apparatus according to claim 12 or 13 wherein each track segment includes one or more inner partition walls defining two or more channels within the track segment for receiving two or more respective carriages.A magnetic levitation apparatus according to any preceding claim wherein each channel comprises a carriage guide for guiding the carriage along a fixed path within the track in the direction of travel.

16. A magnetic levitation apparatus according to any preceding claim wherein the levitation device comprises a body and the second magnetic element is a permanent magnet supported by the body.2517. A magnetic levitation apparatus according to any preceding claim wherein the controller is operative to controller the drive means to vary the speed of travel of the carriage and the magnetically coupled levitation device.30 18. A magnetic levitation apparatus according to any preceding claim furthercomprising a remote controller operative to control the speed of travel of theCMCM CMcarriage, and to control the position of the first magnet array to vary the height and / or pitch and / or roll of the levitation device.

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