WO2010011187A1

WO2010011187A1 - Apparatus and method of lifting objects

Info

Publication number: WO2010011187A1
Application number: PCT/SG2009/000260
Authority: WO
Inventors: Wee Ming Yeo
Original assignee: Wee Ming Yeo
Priority date: 2008-07-23
Filing date: 2009-07-22
Publication date: 2010-01-28
Also published as: SG158773A1

Abstract

An apparatus (100) for lifting an object in a first direction is provided which comprises a first magnet (101 ) for attaching to the object and a rotatable shaft (103) having a plurality of arms (107). When the shaft (103) rotates, the plurality of arms (107) extends upwards and outwards such that a magnetic dipole of a second magnet (111 ) arranged along each end of the plurality of arms (107) is arrangeable in relation to a magnetic dipole of the first magnet (101). In particular, the respective magnetic dipoles of the first and second magnets (101, 111) have a common polar orientation so that a repulsive force is created between the first and second magnets (101, 111), thereby lifting the first magnet (101) and the object attached thereto. A device (400) comprising a plurality of the apparatus (100) is also disclosed.

Description

APPARATUS AND METHOD OF LIFTING OBJECTS

Field of the invention

The present invention relates to an apparatus and method of lifting objects.

Background of the invention

Magnetism, caused by alignment of domains or moving charges within a material, is a well-studied phenomenon. The overall effect of magnetism is either attraction or repulsion. Many applications today rely on magnetism within its processes. For example, scrap yards rely on magnetism for lifting of bulky metals and separation of metals from non-metallic materials.

However, magnetic applications of stationary magnets are limited. In particular, Earnshaw's Theorem states that a collection of point charges cannot be maintained in a stable equilibrium configuration solely by the interaction of the charges. The proof for Earnshaw's Theorem is as follows: For a stationary particle to be in a stable equilibrium, any existing gravitational, electrostatic and/or magnetostatic fields, herein to be collectively known as F , have to be pointing inwards toward the stable equilibrium point. Therefore, the divergence of F (or VF ) cannot be zero. However, Gauss's Law states that SFdS = ^VFdV (where dS and dV are the differentials of the surface area

S V

S and volume V of the particle respectively). Since the particle is in a stable equilibrium, ⁽[JFdS = 0 . However, this necessarily means that <\VFdV = 0 because of Gauss's

Law, which therefore contradicts the earlier assumption that VF ≠ O and therefore<jVFtfF ≠ 0.

V

Accordingly, a corollary to Earnshaw's Theorem is that it is not possible for a stationary magnet to levitate stably on top of another magnet because a stable equilibrium point does not exist.

Thus, complicated systems have to be created so as to levitate and/or lift using magnetic means. For example, the principle of electromagnetism is employed in Maglev trains to produce both levitation and motion. However, their direction of motion is dependent on a pre-determined route (or track). That is, if the pre-determined route is not defined, motion of the Maglev train cannot be achieved.

It is therefore an object of the present invention to provide an apparatus and method of lifting objects using magnetic means and/or simplifies complex designs of existing magnetic systems in doing so.

Summary of the invention

In a first aspect, the invention provides for an apparatus for lifting an object in a first direction. The apparatus comprises a first magnet for attaching to the object and a rotatable member having at least one arm with a second magnet being arranged along a portion of the at least one arm. When the rotatable member rotates, a magnetic dipole of the second magnet is arrangeable in relation to a magnetic dipole of the first magnet. Both the magnetic dipoles of the first and second magnets have a common polar orientation such that a repulsive force is exerted by the second magnet onto the first magnet in the first direction, thereby lifting the first magnet and the object attached thereto in that first direction.

Preferably, the at least one arm is attached to the rotatable member via a moveable hinge so that the at least one arm has the capability to extend upwards and outwards depending on the angular velocity of the member.

More preferably, the at least one arm is flexible. In this case, the at least one flexible arm would extend outwards and upwards when the rotatable member rotates without requiring the moveable hinge.

Preferably, the second magnet is arranged at one end of the at least one arm.

Alternatively, the second magnet may be arranged along the entire circumference of the rotational path of the at least one arm.

More preferably, the apparatus further comprises a plurality of arms having respective second magnets arranged thereto. This may accordingly increase the corresponding repulsion forces exerted by the respective second magnets onto the first magnet in the first direction. Even more preferably, the plurality of arms is evenly spaced.

Preferably, the rotatable member is rotated by a motor and the rotatable member is a shaft.

Preferably, the first magnet is ring-shaped so that the magnetic dipole of the first magnet is constantly arranged in relation to the magnetic dipole of the second magnet as the latter moves through a circular path when the rotatable arm rotates.

Alternatively, the first magnet may comprise an array of individual magnets. Preferably, the array of individual magnets defines a ring arrangement which is either continuous or discontinuous.

Even more preferably, the array of individual magnets is defined using the Halbach array arrangement. By using the Halbach array arrangement, which is a special arrangement of permanent magnets, the magnetic field created at the side of the first magnet facing the second magnet is enhanced whilst the magnetic field on the opposite side of the first magnet is reduced to near zero. This phenomenon is known as one-sided flux. The advantages of using the Halbach array arrangement is that stronger magnet field may be created between the first and second magnets. This may further ensure minimal stray field being produced on the opposite side of the first magnet.

Preferably, the first magnet is for attaching to the object to be lifted via biasing means which may include a spring. Alternatively, the first magnet may be for attaching to the object via a compressible material.

Preferably, the first and second magnets can be permanent magnet or temporary magnet.

More preferably, at least one of the first and second magnets can be an electromagnet. In this case, the magnetic strength of the first and second magnets can be adjusted by varying the magnitude of the electric currents flowing around them. Even more preferably, the first and second magnets (here known as) can be of other materials that is capable of repulsion between each other.

Preferably, the apparatus further includes an gaseous chamber so that other components of the apparatus may be housed within the gas in the chamber. Alternatively, the apparatus may further include a liquid chamber or a vacuum chamber besides an air chamber.

Preferably, the chamber is made up of any light-weight material which may be but not limited to glass, PVC₁ fiber glass, aluminium alloy or kevlar composite.

In addition, a device may also be provided which comprises a plurality of the apparatus so that the cumulative repulsive force exerted by the second apparatus in the same direction becomes greater compared to that as created by a single apparatus. The direction of the apparatus can be changed individually or in unison by changing the position of each apparatus such that the course of the first direction of the device can be altered.

In a second aspect, the invention provides a method of lifting an object in a first direction. The method comprises the steps of attaching a first magnet to the object and rotating a member having at least one arm arranged at one end of the member, wherein a second magnet is arranged along a portion of the at least one arm so that when the member rotates, a magnetic dipole of the second magnet is arranged in relation to a magnetic dipole of the first magnet, due to centrifugal force, the magnetic dipoles of both first and second magnets having a common polar orientation such that a repulsion force is exerted by the second magnet on the first magnet, thereby lifting the first magnet and the object attached thereto.

Preferably, the step of rotating the member may be undertaken by a motor. The step of rotating the member may also be done by any rotating devices.

Preferably, the method further comprises the step of magnetising the first and second magnets by electric currents flowing around them so that the magnetic strength of the first and second magnets may be adjusted by varying the magnitude of the electric currents. Brief description of the drawings

It will be convenient to describe the present invention with respect to the accompanying drawings that illustrate possible arrangements of the invention. Other arrangements of the invention are also possible, and consequently the particularity of the drawings is not to be understood as superseding the generality of the preceding description of the invention.

Figure 1 illustrates a side view of a first embodiment of the invention including a rotatable shaft;

Figure 2 illustrates a top view of the rotatable shaft of Figure 1 including a plurality of arms attached to the shaft;

Figures 3a and 3b illustrate respective top and side views of a first magnet of the first embodiment of Figure 1. Figure 4 illustrates a second embodiment comprising but not limited to three of the first embodiment of Figure 1.

Figures 5a and 5b illustrate possible uses of the ^"second embodiment of Figure 4 and also the possible change of the first direction of the device by altering the position of individual chamber 100.

Detailed description of the embodiments

Figure 1 is a side view of the first embodiment of the invention and illustrates a chamber 100 having a rectangular cross-sectional area. The interior of the chamber

100 comprises a first magnet 101 attached to a support (shown as a lid 108) via biasing means (shown as springs 102), a rotatable member (shown as shaft 103), a motor 105 and a plurality of arms 107. Specifically, one end of the shaft 103 is connected to the motor 105 fixed to the base of the chamber 100, whilst the plurality of arms 107 is attached to the opposite end of the shaft 103 via movable hinges 109. In particular, the movable hinges 109 gives flexibility of the plurality of the arms 107 to move upwards and downwards depending on the angular velocity of the shaft 103. In addition, a second magnet 111 is attached to each respective ends of the plurality of arms 107.

When the motor 105 drives the shaft 103 to rotate, the plurality of arms 107 extends upwards and outwards as shown in Figure 1 due to centrifugal forces acting on the plurality of arms 107 and the plurality of arms 107 is therefore maintained either substantially or fully perpendicular to the axis of rotation of the shaft 103. As the plurality of arms 107 extends upwards and outwards, magnetic dipoles of the second magnets 111 having a particular polar orientation approach and arrange in relation to a magnetic dipole of the first magnet 101 of the same polar orientation.

Optionally, such a change in this angle of the arms 107 with respect to the shaft 103 can be measured using a sensor such as an accelerometer. This may be done by placing the accelerometer on a particular arm 107 and because the voltage output of the sensor is approximately linear between a first position where the arms 107 are arranged alongside the shaft 103 (i.e. the +1g-position) and a second position where the arms 107 are substantially perpendicular to the shaft 103 (i.e. the Og-position), the relationship between the respective voltage output and the angle of the arms 107 can be measured.

In addition, the respective magnetic repulsive forces between the first and the second magnets 101 , 111 may be varied in relation to the position of the arms 107 relative to the shaft 103 based on the voltage output of the accelerometer. Thus, the motion of the apparatus in respect of its lift potential can be controlled by adjusting the respective rotational speed of the second magnets 111 , based on the voltage output of the accelerometer.

Although Figure 1 illustrates the magnetic dipole of the first magnet 101 having a "North" polar orientation facing the corresponding dipoles of the second magnets 111 of the same "North" polar orientation, it should be appreciated that the "South" polar orientation could likewise be used in operations of this embodiment. It should be further appreciated that a combination of "North" and "South" polar orientation can be used in operation as long as the arrangement of the magnetic dipole of the first magnet faces identical magnetic dipole on the second magnet.

Thus, as the common magnetic dipoles of the first and second magnets 101 , 111 are arranged in relation to each other as the shaft 103 rotates, equal and opposite repulsive forces are created between the first and second magnets 101 , 111. However, the upwards resultant force of the plurality of arms 107 due to centrifugal forces acting on the plurality of arm 107 more than offsets the repulsive force that acts on the second magnet 111 by the first magnet 101. The equal and opposite repulsive force that act on the first magnet 101 by the second magnet 111 therefore means that the first magnet 101 is consequently "lifted" and moves in an upward direction 113. As this happens, the springs 102 are compressed due to the upward motion of the first magnet 101 , which thereby lifts the lid 108 in that upward direction 113 also.

Thus, an item (not shown) arranged on lid 108 may therefore be lifted in the upward direction 113 by the repulsive forces created between the first and second magnets 101, 111 in combination with the rotational motion of the shaft 103. Thus, the item can be transported by the chamber 100.

In view of the foregoing operation of the first embodiment illustrated in Figure 1, the chamber 100 can therefore be designed to lift the lid 108 in a desired upward direction by aligning the central axis of the chamber 100 along that desired upward direction. Accordingly, this means that items arranged on the lid 108 may also be lifted along the desired upward direction.

It should be appreciated that the upward motion of the lid 108 is not limited to one that is strictly in the vertical direction, but may also include other directions so long as the distance of the lid 108 relative to a common ground level is increased after such a motion. Advantageously, acceleration of the lid 108 in the desired direction may be incremented or decremented by adjusting the following parameters: i) the angular velocity of the shaft 103; ii) the respective magnetic strengths of the first and second magnets 101, 111; iii) the spaced distance of the common magnetic dipoles of the first and second magnets 101, 111. In addition, motion of the chamber 100 in any desired direction can be achieved by aligning the chamber 100 accordingly along that desired direction or by temporarily altering the position of chamber 100 or by reconfiguring the arrangement of the chamber components accordingly.

It should be appreciated that the first and second magnets 101 , 111 do not have to be permanent magnets. Instead, at least one of the first and second magnets 101 , 111 may be magnetised by alternating electric currents. In this way, the magnetic strength of the magnet so magnetised can further be adjusted based on the magnitude of such alternating electric currents. Similarly, any material capable of repulsion between them can be appreciated.

Figure 2 illustrates a top view of the shaft 103 having the plurality of arms 107 attached to the top end of the shaft 103. As shown in Figure 2, the plurality of arms 107 extends fully upwards and outwards when the shaft 103 rotates so that the plurality of arms 107 is maintained either substantially or fully perpendicular to the axis of rotation of the shaft 103.

Figure 3a and 3b illustrate respective top and side views of the first magnet 101. It is seen from Figure 3a that the first magnet 101 has a ring-shaped structure. Alternatively, the first magnet 101 may be an array of individual magnets arranged as a ring-shaped structure. For example, by employing a Halbach array arrangement of individual magnets, maximum repulsion may be achieved with minimal magnetic materials, as explained earlier.

Figure 4 illustrates a second embodiment of the invention and illustrates a device 400 comprising three of the chambers 100 of the first embodiment so as to create a larger overall thrust on the Hd 408 as compared with that on the lid 108 of a single chamber 100 in the first embodiment.

It should be appreciated that the accelerometer described earlier in the context of the first embodiment can also be used in this second embodiment. By varying magnetic strength of respective first and second magnets 101 , 111 of some or all the chambers 100 that make up the device 400, the motion of the device 400 in respect of its speed can be controlled based on the voltage output of the accelerometer. In addition, motion of the device 400 in any desired direction can be achieved by aligning the device 400 accordingly along that desired direction or by temporarily altering the position of chamber 100 or by reconfiguring the arrangement of the device components accordingly. Thus, an item can be transported by the device 400.

Figures 5a and 5b show two possible uses of the second embodiment for recreational purposes. In Figure 5a, a device 501 comprising four of the chambers 100 according to the first embodiment is used for conducting a barbeque gathering among families and/or friends. In Figure 5b, a device 503 comprising three of the chambers 100 also according to the first embodiment is used in an amusement park for visitors for offering fun rides to visitors. Both these examples of Figures 5a and 5b work on the same principles as explained earlier. In particular, it should be appreciated that motion of the devices 501, 503 in a desired direction 500, 502 can be achieved by aligning the devices 501, 503 accordingly along that desired direction 500, 502, or by temporarily altering the position of chamber 100 or by reconfiguring the arrangement of the components of the devices 501 , 503 accordingly.

It is envisaged that the chamber 100 may also be any one of a vacuum chamber; gaseous chamber; or liquid chamber. Embodiments of the invention may therefore be used in by way of examples but not limiting to any of the following: i) for levitation and/or transportation of animals and objects and/or ii) for entertainment.

It is further envisaged that the plurality of arms 107 to which the second magnets 111 are attached may include flexible wires or connectors. In addition, the plurality of arms

107 may also be rigidly attached to the shaft 103. In this case, the magnetic dipole of the first magnet 101 facing the corresponding dipoles of the second magnets 111 are spaced apart from each other in a predetermined distance prior to the rotation of the shaft 103. Nevertheless, the rotation of the shaft 103 may still be necessary so as to lift the lid 108, 408 of the chamber 100, 400 in the desired direction.

Although the invention has been described above using particular embodiments, many variations are possible within the scope of the claims, as will be clear to the skilled reader without departing from the scope of the claims.

Claims

1. An apparatus for lifting an object in a first direction, the apparatus comprising: a first magnet for attaching to the object; a rotatabie member having at least one arm; and a second magnet arranged along a portion of the at least one arm so that when the rotatabie member rotates, a magnetic dipole of the second magnet is arrangeable in relation to a magnetic dipole of the first magnet, the magnetic dipoles of the first and second magnets having a common polar orientation such that a repulsive force is exerted by the second magnet onto the first magnet in the first direction, thereby lifting the first magnet and the object attached thereto in that first direction.

2. The apparatus of claim 1, wherein the at least one arm is attached to the rotatabie member via a moveable hinge.

3. The apparatus of claim 1 or claim 2, wherein the at least one arm is flexible or movable.

4. The apparatus of any one of the preceding claims, wherein the second magnet is arranged at one end of the at least one arm.

5. The apparatus of any one claims 1 to 3, wherein the second magnet is arranged along the entire outer circumference of the at least one arm.

6. The apparatus of any one of the preceding claims, further comprising a plurality of arms.

7. The apparatus of claim 6, wherein the plurality of arms is evenly spaced.

8. The apparatus of any one of the preceding claims, wherein the rotatabie member is rotated by a motor.

9. The apparatus of any one of the preceding claims, wherein the rotatabie member is a shaft.

10. The apparatus of any one of the preceding claims, wherein the first magnet is ring-shaped.

11. The apparatus of any one of claims 1 to 9, wherein the first magnet comprises an array of magnets. .

12. The apparatus of claim 11 , wherein the array of magnets defines a continuous ring arrangement.

13. The apparatus of claim 11 , wherein the array of magnets defines a discontinuous ring arrangement.

14. The apparatus of any one of claims 11 to 13, wherein the array of magnets is arranged in a Halbach array.

15. The apparatus of any one of the preceding claims, wherein the first magnet is attached to the object via biasing means.

16. The apparatus of any one of claims 1 to 14, wherein the first magnet is attached to the object via a compressible material.

17. The apparatus of any one of the preceding claims, wherein the first and second magnets are magnets selected from the group comprising but not limited to: permanent magnets; temporary magnets; and materials that can repel.

18. The apparatus of any one of the preceding claims, further comprising a gas chamber.

19. The apparatus of any one of claims 1 to 17, further comprising a vacuum chamber.

20. The apparatus of any one of claims 1 to 17, further comprising a liquid chamber.

21. The apparatus of any one of claims 18 to 20, wherein the chamber is made of a light-weight material selected from a group comprising but not limited to: glass; PVC; fiber glass; aluminium alloy; and keviar composite.

22. An apparatus comprising a plurality of the apparatus of any one of claims 1 to 21.

23. The apparatus of claim 22 operable to move in a selected direction, the selected direction being the first direction.

24. The apparatus of claim 23, wherein the chambers are arrangeable individually or in unison for lifting the object in the selected direction, the selected direction being the first direction.

25. A method of lifting an object in a first direction using the apparatus of any one of claims 1 to 24.