WO2001057993A1

WO2001057993A1 - Magnetic drive mechanism

Info

Publication number: WO2001057993A1
Application number: PCT/AU2001/000094
Authority: WO
Inventors: John Edward Maher
Original assignee: John Edward Maher
Priority date: 2000-02-03
Filing date: 2001-02-05
Publication date: 2001-08-09
Also published as: AUPQ541000A0

Abstract

A magnetic drive mechanism (1) is provided which comprises a first rotatable shaft (4) and a crank means (5) including a second rotatable shaft (8) linked to the first shaft. A first, cam-shaped magnet (2) is mounted for eccentric movement on the first shaft (4) and a second, block magnet (3) is mounted on the second shaft (4) of the crank means (5) for reciprocating movement relative to the first shaft (4). The magnets (2) and (3) are maintained in close proximity during operation so that a reciprocating movement of the second magnet (3) is accompanied by rotations of the first and second shaft (4) and (8).

Description

MAGNETIC DRIVE MECHANISM

FIELD OF INVENTION

This invention relates to a magnetic drive mechanism driving a wide variety of machines for use in industry or domestic applications. BACKGROUND OF INVENTION

With world energy resources, such as fossil fuels, being slowly depleted it has become apparent that there is a need to develop more effective mechanisms for driving engines and other machines for use in industrial or domestic applications. It is therefore desirable to provide a device or mechanism which can efficiently supply mechanical energy for industry or domestic purposes. SUMMARY OF INVENTION

In accordance with one aspect of the invention there is provided a magnetic drive mechanism comprising: a first rotatable shaft, a first magnet mounted on the first rotatable shaft for eccentric movement relative to the shaft, and a crank means including a second magnet mounted for reciprocating movement relative to the first rotatable shaft; wherein there is a magnetic interaction between the first and second magnets such that a reciprocating movement of the second magnet is accompanied by a rotation of the first rotatable shaft.

Preferably, the magnet is cam-shaped to accommodate the reciprocating motion of the second magnet of the crank means thereby retaining a small gap between the cam shaped magnet and the second magnet during the reciprocating movement of the second magnet and rotation of the first rotatable shaft. It is also preferable that the first magnet comprises two halves of opposite magnetic polarity and shaped as a mirror image of each other.

Preferably, the crank means includes a second rotatable shaft connected by crank journal means to one end of a reciprocating rod, the second magnet being supported on the opposite end of the rod, said crank journal means enabling rotation of the second shaft on reciprocal movement of the second magnet and rod in response to magnetic interaction of the second magnet with the first magnet.

In further preference, the first rotatable shaft is substantially parallel with the second rotatable shaft and is linked thereto by timing means so that the first and second shafts rotate in unison. The first and second rotatable shafts may, for instance, be linked by engaging toothed wheels or an endless belt or other convenient linkage.

It is also preferable that the second magnet is a block magnet mounted in a housing on said opposite end of the reciprocating rod by adjustable mounting means.

Preferably, the adjustable mounting means enables the proximity of the block magnet to the cam shaped magnet to be adjusted thereby varying the magnitude of attractive and repulsive magnetic forces between the magnets. Also, the mounting means preferably includes a solenoid which is arranged to move the block magnet towards or away from the first magnet.

In further preference, the solenoid is adapted to move the block magnet to an off position where the attractive or repulsive magnetic force between the cam shaped magnet and block magnet is not sufficient to cause reciprocal movement of the block magnet, and to move the block magnet into an operating position where the attractive and repulsive magnetic forces cause reciprocal movement of the block magnet.

Preferably, the first magnet is generally heart shaped, and is eccentrically mounted on the parallel shaft. The magnetic drive mechanism preferably includes two or more sets of eccentrically mounted first magnets and corresponding second magnets are respectively mounted on the first and second rotatable shafts, said first and second magnets of each set being retained in close magnetic relation without touching. The reciprocal motions of adjacent second magnets are 180° out of phase. More preferably, the reciprocal motions of adjacent second magnets are 90° out of phase.

The or each first magnet and/or second magnet may comprise a ferrite, a ferromagnetic alloy including one or more rare earth elements, or a ferrimagnetic material.

In order that the invention may be more fully understood, a preferred embodiment will now be described by reference to the accompanying drawings. Figure 1 depicts a magnetic drive mechanism in accordance with one embodiment of the invention.

Figure 2 illustrates an alternative embodiment by which the crank means and parallel shaft are linked.

Figures 3 and 4 illustrate one particular embodiment of the cam shaped magnet and the mounting thereof to the first rotatable shaft, respectively. Figures 5A-5E are a step wise depiction of the reciprocal motion of the second magnet with the corresponding rotation of the first magnet in accordance with the invention.

Figure 6 is a schematic diagram of the adjustable mounting means. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Figure 1 depicts a preferred embodiment of the magnetic drive mechanism 1 including first magnets 2, mounted on a first rotatable shaft 4 arranged parallel to a second shaft 8 of crank means 5. Second, block magnets 3 are mounted on one end of a reciprocating rod 10 which is attached at its opposite end to second shaft 8 via crank journal means 9, thereby enabling reciprocal movement of the second magnet 3 relative to the first rotatable shaft 4. The second shaft 8 of the crank means 5 is operatively linked to the first rotatable shaft 4 via engaging toothed wheels 12.

Although the magnetic drive mechanism 1 preferably includes two or more sets of corresponding first magnets 2 and second magnets 3, the operation of the invention shall initially focus on a description of a magnetic drive mechanism 1 including only one first magnet 2 and second magnet 3. The first magnet 2 preferably is cam shaped and adapted to closely accommodate the reciprocal movement of the second magnet 3 during rotation of the first rotatable shaft 4. In order to accommodate such reciprocal movement, the cam-shaped magnet 2 is eccentrically mounted on the first rotatable shaft 4. In this arrangement the highest point of the second magnet 3 during reciprocal movement is adjacent to the portion of the cam-shaped magnet 2 with the smallest radius in relation to the eccentric mounting point. Conversely, the lowest point of the second magnet 3 during reciprocal movement is adjacent the portion of the cam-shaped magnet 2 with the greatest radius. In each position a small gap is retained between the cam-shaped magnet

2 and second magnet 5.

Preferably the cam-shaped magnet 2 is generally heart shaped with a small rounded indent at the portion of the cam-shaped magnet 2 with the smallest radius, as shown in Figure 3. The cam-shaped magnet 2, regardless of shape, preferably comprises two halves 6,7. Each half 6,7 is a mirror image of the other and has an opposite magnetic polarity to the other half.

In the form depicted in Figure 3, the cam-shaped magnet 2 has halves 6,7 which are shaped as portions of a spiral where the spiral is centred on the first rotatable shaft 4. Each half 6,7, in reference to the eccentrically disposed first rotatable shaft 4, defines a perimeter with a gradually decreasing radius when beginning from point 17 and moving around to point 18.

The second magnet 3 is mounted on a first end of rod 10 on adjustable mounting means (not shown) which allows the proximity of the second magnet

3 to the cam-shaped magnet 2 to be adjusted. Adjusting the proximity of the second magnet 3 to the cam-shaped magnet 2 affects the magnitude of the force realised by their magnetic interaction. That is, moving the second magnet 3 closer to the cam-shaped magnet 2 increases the magnitude of the force generated by the interaction of the magnetic fields of the second magnet 3 and cam-shaped magnet 2. It is, therefore, desirable to have both the second magnet 3 and cam-shaped magnet 2 as close to each other as possible, without touching, in order to generate an attractive or repulsive magnetic force sufficiently great to drive the magnetic drive mechanism 1 and any machine coupled thereto.

Preferably, the second magnet 3 is guided for its reciprocal movement by linear bearings (not shown) contacting with the adjustable mounting means. The crank journal means 9 may comprise a ring bearing or any other bearing arrangement suitable for allowing the rod 10 to move in a reciprocating motion on rotation of the second rotatable shaft 8.

The second rotatable shaft 8 is preferably linked to the first rotatable shaft 4 by equally sized engaging toothed wheels 12 mounted on the second rotatable shaft 8 and first rotatable shaft 4. In this manner, the first rotatable shaft 4 is caused to rotate at the same rate as the second rotatable shaft 8 but in the opposite direction.

In an alternative embodiment the second rotatable shaft 8 and the first rotatable shaft 4 may be linked by an endless belt 13 supported on rollers 14 mounted on the first and second rotatable shafts 4,8, respectively. This linkage will rotate the first and second rotatable shafts 4,8 at the same rate and in the same direction.

The magnetic interaction of the second magnet 3 with the cam-shaped magnet 2 and the consequential rotation of the second rotatable shaft 8 and first rotatable shaft 4 will now be described by reference to Figures 5A to 5E and

Figure 1.

Referring firstly to Figures 5A to 5E, the cam-shaped magnet 2 comprises a half 6 designated as having a north magnetic polarity and another half 7 designated as having a south magnetic polarity. The upper part of the second magnet 3, mounted on rod 10, is designated as also having south magnetic polarity. The arrangement of the cam-shaped magnet 2 and second magnet 3 in Figure 5A represents the second magnet 3 at the lowest most point of its reciprocating motion. This arrangement of the magnetic drive mechanism

1 is also shown by the cam-shaped magnet 2 and corresponding second magnet 3 which are adjacent the engaging toothed wheels 12 in Figure 1. At the bottom of the reciprocating motion there is magnetic repulsion between the second magnet 3 and the half 7 of the cam-shaped magnet 2 having the same magnetic polarity and magnetic attraction between the second block magnet 3 and the oppositely magnetically polarised half 6 of the cam-shaped magnet 2. This causes the cam-shaped magnet to rotate in the direction of arrow R in Figure 5. Due to the relative proximity of the second magnet 3 to the cam-shaped magnet 2, the attractive magnetic force between the second magnet 3 and the half 6 of magnet 2 raises the second magnet 3. By virtue of the second magnet 3 being mounted on the crank means 5, the attractive magnetic force causes the second rotatable shaft 8 to rotate, thereby allowing the second magnet 3 to move through an upstroke as shown in Figure 5B.

As the first rotatable shaft 4 is rotated, the cam-shaped magnet 2 rotates about the eccentric mounting point such that the gradually diminishing radius of the oppositely magnetically polarised half 6 of the cam-shaped magnet 2 ensures that the proximity of the second magnet 3 to the cam-shaped magnet 2 is maintained substantially constant as depicted in Figures 5 A and 5B. Therefore, the attractive magnetic force is also maintained substantially constant throughout the upstroke.

At the top of the upstroke as shown in figure 5C the first rotatable shaft 4 has developed an angular momentum which carries the second magnet 3 across the divide between the two oppositely polarised halves 6,7 of the cam-shaped magnet 2 at the point 18 of minimum radius from the eccentrically mounted parallel shaft 4.

In this configuration the second magnet 3 is in close proximity to the half 7 of the cam-shaped magnet 2 which has the same magnetic polarity as the second magnet 3. Consequently, a repulsive magnetic force arises between the second magnet 3 and cam-shaped magnet 2, whereby the repulsive forces pushes the second magnet 3 through a downstroke, as depicted in Figures 5D and 5E. The repulsive force, in urging the second magnet 3 downward, causes the second rotatable shaft 8 to rotate and in turn drives rotation of the first rotatable shaft 4 and cam-shaped magnet 2 via the engaging toothed wheels 12.

The gradually increasing radius of the similarly polarised half 7 of the cam-shaped magnet 2 ensures that the gap between the cam-shaped magnet 2 and the second magnet 3 remains substantially the same during the downstroke and consequent rotation of the cam-shaped magnet 2. This also ensures that the magnitude of the repulsive magnetic force remains substantially constant during the downstroke, thereby continuing to drive the rotational movement of the first and second rotatable shafts 4,8.

At the bottom of the downstroke, as illustrated in Figure 5A, the angular momentum of second rotatable shaft 8 and linked first rotatable shaft 4 and the repulsion of the second magnet 3 away from the half 7 of the cam-shaped magnet 2 ensure that the second magnet 3 is moved into proximity with the oppositely magnetically polarised half 6 of the cam-shaped magnet 2. In this arrangement, the attractive magnetic force pulls the second magnet 3 through an upstroke as previously described, thereby continuing the reciprocal movement of the second magnet 3 and maintaining the driven rotation of the first and second rotatable shafts 4,8. As previously mentioned the adjustable mounting means controls the proximity of the second magnet 3 in relation to the cam-shaped magnet 2. Preferably the adjustable mounting means (not shown) is a releasable gripping means whereby releasing the gripping means enables the second magnet 3 to be freely repositioned at the desired proximity to the cam-shaped magnet 2. The releasable gripping means may be spring biased, operable by a threaded screw or bolt which clamps the second magnet 3 in position or may otherwise comprise any suitable gripping means.

When it is desired to stop the reciprocating motion for the performance of maintenance operations or otherwise, the second magnet 3 may be moved to an off position in which the magnetic interaction of the second magnet 3 with the cam-shaped magnet 2 is not sufficient to drive the reciprocating movement. The movement of the second magnet 3 between the operative position and the off position is preferably achieved by a solenoid 15 disposed in a housing 11 on the end of rod 10, as shown in Figure 6. The solenoid 15 controls the height of a stage 16 on which the second magnet is mounted. Raising the stage 16 moves the second magnet 3 into the operative position, while lowering the stage 16 moves the second magnet 3 into the off position.

The operation of the magnetic drive mechanism 1 has so far been described in reference to only one cam-shaped magnet 2 and corresponding second magnet 3. The magnetic drive device may, however, comprise more than one set of corresponding cam-shaped magnets 2 and second magnet 3.

Figure 1 illustrates one particular preferred embodiment with two cam- shaped magnets 2 and second magnets 3 where each set of corresponding magnets is arranged to operate 180° out of phase in respect of the other set of corresponding magnets. This arrangement advantageously means that the angular momentum of the second rotatable shaft 8 and first rotatable shaft 4 is aided in urging the second magnet 3 of one corresponding set of magnets into proximity with the half 7 of the cam-shaped magnet 2 by the rotation of the second rotatable shaft 8 caused by the additional second magnet 3 of the other corresponding set of magnets being attracted to the oppositely polarised half 6 of the second cam- shaped magnet 2.

In an alternative embodiment there are four sets of corresponding second magnets 3 and cam-shaped magnets 2. Preferably, each corresponding set is operatively 90° out of phase with the remaining three corresponding sets. Preferably, the or each cam-shaped magnet 2 and/or the second magnet 3 consists of a ferromagnetic material, such as steel or a ferrite. Alternatively, the ferromagnetic material may be a ferromagnetic alloy including one or more rare earth elements. The ferromagnetic material may equally be substituted by a ferrimagnetic material. It will be appreciated that various modifications and alterations may be made to the preferred embodiment of the magnetic drive mechanism described above without departing from the scope and spirit of the invention. For example, the magnitude of the dipole moment of each magnet, the material comprising the magnets, the size of gap between the second magnet 3 and cam- shaped magnet 2, and the number of corresponding sets of magnets comprising the magnetic drive mechanism, or any combination, may be varied to affect the magnitude of the driving force generated by the magnetic drive mechanism 1.

Claims

CLAIMS:

1. A magnetic drive mechanism comprising: a first rotatable shaft, a first magnet mounted on the first rotatable shaft for eccentric movement relative to the shaft, and a crank means including a second magnet mounted for reciprocating movement relative to the first rotatable shaft; wherein there is a magnetic interaction between the first and second magnets such that a reciprocating movement of the second magnet is accompanied by a rotation of the first rotatable shaft.

2. A magnetic drive mechanism according to claim 1, wherein the first magnet is cam-shaped to accommodate the reciprocating motion of the second magnet of the crank means thereby retaining a small gap between the cam shaped magnet and the second magnet during the reciprocating movement of the second magnet and rotation of the first rotatable shaft.

3. A magnetic drive mechanism according to claim 2, wherein the first magnet comprises two halves of opposite polarity and shaped as a mirror image of each other.

4. A magnetic drive mechanism according to any one of claims 1 to 3, wherein the crank means includes a second rotatable shaft connected by crank journal means to one end of a reciprocating rod, the second magnet being supported on the opposite end of the rod, said crank journal means enabling rotation of the second shaft on reciprocal movement of the second magnet and rod in response to magnetic interaction of the second magnet with the first magnet.

5. A magnetic drive mechanism according to claim 4 wherein the first rotatable shaft is substantially parallel with the second rotatable shaft and is linked thereto by timing means so that the first and second shafts rotate in unison.

6. A magnetic drive mechanism according to claim 5, wherein the first and second rotatable shafts are linked by engaging toothed wheels.

7. A magnetic drive mechanism according to claim 5, wherein the first and second rotatable shafts are linked by an endless belt.

8. A magnetic drive mechanism according to any one of claims 4 to 7 wherein the second magnet is a block magnet mounted in a housing on said opposite end of the reciprocating rod by adjustable mounting means.

9. A magnetic drive mechanism according to claim 8, wherein the adjustable mounting means enables the position of the second magnet relative to the first magnet to be adjusted thereby varying the magnitude of attractive and repulsive magnetic forces between the magnets.

10. A magnetic drive mechanism according to any one of claims 4 to 9, wherein the mounting means for the second magnet includes a solenoid arranged to move the second magnet towards or away from the first magnet.

11. A magnetic drive mechanism according to claim 10, wherein the solenoid is adapted to move the block magnet to an off position where the attractive or repulsive magnetic force between the first magnet and second magnet is not sufficient to cause reciprocal movement of the second magnet, and to move the second magnet into an operating position where the attractive and repulsive magnetic forces cause reciprocal movement of the second magnet.

12. A magnetic drive mechanism according to any one of the preceding claims, wherein the first magnet is generally heart shaped.

13. A magnetic drive mechanism according to any one of claims 4 to 11, wherein two or more sets of first magnets and corresponding second magnets are respectively mounted on the first and second rotatable shafts, said first and second magnets of each set being retained in close magnetic relation without touching.

14. A magnetic drive mechanism according to claim 13, wherein the reciprocal motions of adjacent second magnets are 180° out of phase.

15. A magnetic drive mechanism according to claim 13, wherein the reciprocal motions of adjacent second magnets are 90° out of phase.

16. A magnetic drive mechanism according to any one of the preceding claims, wherein the or each first magnet and/or second magnet comprises a ferrite.

17. A magnetic drive mechanism according to any one of claims 1 to 15, wherein the or each first magnet and/or second magnet comprise a ferromagnetic alloy including one or more rare earth elements.

18. A magnetic drive mechanism according to any one of claims 1 to 15, wherein the or each first magnet and/or second magnet comprises a ferrimagnetic material.