GB2491174A

GB2491174A - Magnetic mechanism with push-pull rotational and linear motion

Info

Publication number: GB2491174A
Application number: GB1108886.1A
Authority: GB
Inventors: Patrick Chaizy
Original assignee: Individual
Current assignee: Individual
Priority date: 2011-05-26
Filing date: 2011-05-26
Publication date: 2012-11-28
Also published as: GB201108886D0

Abstract

A magnetic mechanism with push-pull rotational and linear motion comprises two sets 1, 2 of two or more dipolar magnets, where at least two of the magnets of each set 1, 2 are oppositely aligned and where a mounting mechanism for the two sets 1, 2 of magnets is arranged to allow relative rotation between the said sets 1, 2 and consequential linear motion. The mechanism may include internal and/or external guide members 6, 7 and at least one of the magnet sets 1, 2 is arranged to slide along the inside and/or outside of the mechanism guide member 6, 7. The mechanism may be used in various hinge, joint, lock and/or switch arrangements. The mechanism can be totally hidden from view and used in quick assembly systems.

Description

1 Introduction

The first sub-section below provides some background information about the proposal as well as the structure of the document. It is then followed by a convention used all along this document.

1.1 Background

Locking the alignment of two parts can be done mechanically or via the use of fundamental forces. An example of such fundamental force is the magnetic force; various patents about using magnetic force to align two parts exist; see for instance, some of the patents published by Fullerton et al. from 2008 till 2011 (see A mecha nical locking requires the use of splints and/or shaft. The problem is that the positioning and/or removing the splint/axes can take some times (e.g. if the shaft is a screw) and can require a direct access to the latter (e.g. screws require being accessible to screwdrivers). In addition, positioned splint/axes can dislodge themselves in an unwanted way (e.g. screw can unscrew themselves through ambient vibrations, frictions etc...).

Therefore, the purpose of the present proposal is to provide a solution to the above problems in some circumstances. It can allow the splint/shafts to be moved rapidly, to be moved without the need to have a physical access to the splint/axes and/or to be more securely positioned.

Such properties have several potential advantages. For instance, the rapidity to lock/unlock the alignment can save time (and money) and the ability to move the shaft without direct access allows the latter to be hidden inside the elements to be kept aligned (for practical or aesthetic reasons).

In addition, the above mentioned solution can also be used as switch.

Consequently, the first section describes the concepts associated to this proposal and how these concepts fit within the ones already in the public domain. It is followed by some examples of devices based on the principle of the proposal.

1.2 Convention In order to avoid ambiguities, the following distinction is made between orientation and direction: El t 4, the two arrows have the same orientation but different directions El t t the two arrows have the same orientation and the same directions El 1" 4 the two arrows do not have the same orientation and do not have the same direction

2 Summary of the proposal

El The proposal comprises two sets of linear multi-polar magnets, at least one of which is rotatable relative to the other, and at least one of which can be moved away from the other. A relative rotation of the two sets of magnets results in an inversion of the magnetic force direction and in a relative linear motion of the two sets. The magnets are mounted on a mechanism that guides their motion. The system can be used as rotating joints, as locking mechanism or as switches.

El Such device can be used, for instance, as door hinges, as structure component fixing (including toilet roll holder), as folding devices (including wall mounted tables/panels) or as electrical switches.

El Embodiment features of the proposal include: * The use of external and internal guides * Any rotational angle required to reverse the magnetic force; hence any number and shapes of magnetic polarities * The use or not of additional external device (e.g. a screwdriver) to rotate the magnets relatively to each others.

* Alignment/misalignment that results either of a sheer movement or of a folding motion * Built-in guides; i.e. guides that are merely a geometrical feature of the body that uses the device and, subsequently, cannot be separated from the main body (because they do not exist as such).

* Attached guides, i.e. guides that are attached by traditional means (e.g. screwed, glued etc...) to the main body that uses the device and, subsequently, that can be separated from the main body.

* Alignment locking resulting of the magnets being pulled towards or pushed away from each other's * Alignment unlocking resulting of the magnets being pulled towards or pushed away from each other's * Any types of cross sections shapes of the magnets and of the parts * Multiple alignment locking mechanisms by mean of which one magnet is shared by all the individual mechanisms * Any type of friction value between the magnets and the guides, between the guides and the guides as well as between the magnets and the magnets * Magnets that use Halbach's arrays and mu-metal to control the maximum distance between the two magnets beyond which friction forces prevent the magnets to be pulled towards each other's * Partial magnetisation of the magnets; i.e. only the extremity of the magnets is magnetised Magnet rotation locking system; to lock the rotation of magnets A and B and, subsequently, to lock the alignment locking/unlocking

3 Description of embodiments of the proposal

The splints/shafts are made of a combination of multi-polar magnets used in push-pull types of devices. The force that generates the push-pull motion is the magnetic force that is created by the multi-polar magnets. This means that the magnets are pushed and pulled to lock and unlock the alignment (or vice versa). Such push-pull requires that the motion of the magnets is controlled by guides. Therefore, the guides are the parts of which alignment is to be locked/unlocked by the splints/shafts. Thus the sections below describe the: El Multi-polar magnets El Push-pulls El Guides A key point is that the magnetic force is not directly used to hold the parts aligned but to pull the magnet together. The alignment is locked by the rigidity of the material that is used to make and/or to wrap the magnets.

3.1 Multi-magnets Hereafter, multi-magnets devices designate systems that involve two magnetised surfaces that face each others and of which resulting magnetic force strength, and sometimes direction, vary as a result of a combination of two features. The first feature is a spatial variation of the magnetic field intensity, and sometimes direction, across at least one of the surfaces. The second feature is a motion of the surfaces, relatively to each others, which is perpendicular, or quasi-perpendicular, to the surface normals and triggered by a force that is external to the system.

Multi-magnets surfaces can be mono-polar or multi-polar. If they are mono-polar then only the intensity of the magnetic field can vary across the surface, not its direction. If they are multi-polar then both the magnetic filed intensity and its direction can vary across the surface. In both case, the magnetic dipoles are parallel, or quasi parallel, to the surface normals.

Multi-polar multi-magnets devices have been mentioned on several occasions. For instance, Koshimoto (1988, JP63099506(A)) uses a linear motion while Tavano (1965, U53288511), Underwood et al. (2001, U56707360), Vincentelli (2002, US6963261) or Fiedler (2006, U57889036) use rotational motion. Both use simple magnetic force variations across surfaces. More recently, Fullerton et al. (2008 to 2011; extensively studied the relationship between the force modulation as a function of the magnetic variations and motion across the two facing surfaces, thus enabling various complex force modulations. Fullerton et al. refer such magnetic force variations as correlated magnetism, correlated field emissions, correlated magnets, coded magnetism, or coded field emissions. Fullerton et al. also propose various mechanisms exploiting such multi-polar magnets with complex responses as well as some specific applications based on these mechanisms.

The principle of multi-polar multi-magnets is illustrated in Figure 1. Figure 1 represents two sets of two linear dipolar magnets. One set of two magnets is called "magnet A" (1) and the other one "magnet B" (2). Each set is made of two half cylinders magnets (e.g. 3 or 4) that are joined together to make a cylinder magnet (e.g. 1 or 2). Each half-cylinder is crossed by a dipole axis of which orientation is parallel to the height of the cylinder. However, when assembled into one cylinder, the dipole axes of each half-cylinder are oppositely aligned.

Therefore, when magnets A (1) and B (2) are aligned with each others, they will either attract, see row 1 (ri) of Figure 1, or repulse each others, see row 2 (r2) of Figure 1, depending on their relative orientation. Column 1 (ci) represents a perspective view of magnets A (1) and B (2). Column 2 (c2) represents a cross section of the magnets A and B (1 & 2) through a plan that contains the axis of the cylinder and that is perpendicular to the plan (5) that is at the interface of the two half cylinders. The circular arrow represents the axis of rotation of the magnet relatively to each others. The North and South poles of the dipole axis are represented by the letters "N" and "5", respectively. In Figure 1 the magnets are bi-polar. This implies a rotation of 1800 to invert the magnetic force direction; i.e. between ri and r2 magnet B has rotated by 180°. This is just an example. Other magnetic polarisations, and subsequently force inverting rotational angles, are possible. For instance quadric-polar surfaces, with alternative dipole axis directions, would imply a rotation of 90° only to invert the direction of the magnetic force. Figure 3 illustrates such a configuration. It is similar to column 1 (ci) of Figure 1 but with quadric-polar surfaces.

3.2 Push-pull A push-pull is a system that involves multi-magnets to push or pull the facing surfaces, respectively, away from and towards each others and in a guided way. In effect, magnetic push-pulls execute motion transformations. Typically, they can execute rotational to linear motion transformations or change the direction of a linear motion. For rotational to linear motion the axis of rotation can be perpendicular, or quasi-perpendicular, to the orientation of the linear motion. It can also be parallel or quasi-parallel to the orientation of the linear motion. All multi-magnet push-pulls push or pull the two surfaces via a magnetic force and all need, somehow, to reverse the motion i.e., respectively, to pull and push back the surfaces. To execute the motion reversal an additional force is required. If the push-pull is mono-polar, then the additional force can be anything. For instance, it can be the gravitational force, a spring force, an electrical force etc see, for instance Naudin (1998, http:J/naudinJree,fr/htrn!/2magpup.htm). It can also be magnetic. In that case, at least one of the surfaces is multi-polar and the combination of the variation of magnetic field intensity across the surfaces and of the relative motion of the surfaces is such that the resulting magnetic force can be inverted (as it is the case, for instance, in Figure 1).

The proposal described in this patent exploits the two extreme distances, between the magnets, which are reached at the end of the push and pull motions for multi-polar parallel, or quasi-parallel, push-pulls; as opposed to the exploitation of the motion itself (e.g. Naudin, 1998, httpjJJinaudin.free.frLhtmjJ2magpuphtm) or of intermediate distances. One distance is used to lock (or unlock) the alignment while the other one is used to unlock (or lock) the alignment. Hereafter, such devices are called Binary Parallel Rotational Magnetic (BIPAROMAG) Push-Pull devices.

3.3 Guides BIPAROMAG push-pulls require that the motion of the magnets is controlled by guides; i.e. the guides act as mounting mechanism for the magnets. The guides are also the parts, hereafter called part A and part B, of which alignment is locked/unlocked by the magnets.

This means that at least one of these magnets is able both to slide inside or around (see below) the two guides and to straddle the two guides. This sliding magnet locks the alignment when it straddles the two parts. Oppositely, the alignment is unlocked when this sliding magnet does not straddle the two parts.

In order not to interfere with the magnets the guides should be a magnetic, i.e. made of a material that is magnetically neutral such as plastic, wood, aluminium etc...

There are three possible types of guide: internal, external and a combination of both. The internal and external guides are described in the two first sub-sections below. The third type is not described as it is merely a simultaneous use of both internal and external guides.

Depending on the purpose of the BIPAROMAG push-pull devices (see, for instance, section 4), the shape of the sections of the magnets and of the (external and internal) guides can be anything but are expected to be, typically, circular (as in Figure 1) or square. The relative shape of the cross sections of the magnets and of the guide will dictate whether one can rotate inside or around the other. For instance, a square magnet cannot rotate inside a square guide but can rotate inside a circular guide.

3.3.1 External guides By definition an external guide acts on the external edges of the magnets (1 & 2). In practice, an external guide is typically a case in which the sliding magnet, say magnet B (2), can slide and, if required, rotate.

The principle of external guides is illustrated in Figure 3. In this figure, the guide is a case (6 & 7). It is represented as a cross section similar to the one described in column 2 (c2) of Figure 1. The circular arrow represents the rotation of the magnets with respect to each others (i.e. not with respect to the guide). In both rows (rl & r2) the parts (6 & 7) are aligned. In row 1 (rl) the alignment is unlocked. In row 2 (r2) the alignment is locked. In the example described in Figure 3, the parts are locked when the magnets are pushed away from each others. It could have been the opposite by moving closer to magnet A (1) the junction of part A (6) and B (7).

Dolge (1902, DE145325C) proposed a device with external guides for a specific type of applications. However, the current proposal improves upon Dolge's invention in several ways. First, it uses multi-polar magnet, not U-shape magnets. This makes the overall system more compact. It also allows controlling the angle of rotation that will trigger the magnetic force reversal. Indeed, Dolge's invention requires that the rotational angle that is required to reverse the magnetic force is unique and equals to 180°. On the contrary, with the current proposal the rotational angle can be anything; this is due to the use of multi-polar magnets (see section 3.1). Second Dolge's invention only covers misalignment by sheer movement while the present proposal also covers folding parts; e.g. see row 3 (r3) of Figure and Figure 11 and column 3 (c3) of Figure 12. Third, Dolge's invention point to one type of embodiment that is built-in guides; i.e. the guide is merely a shape of the main body that uses the device (e.g. see Figure 10) and cannot be separated from the main body because it does not exist as an independent entity. The current proposal includes this type of embodiment but also another one where the guides are attached (e.g. screwed or glued) to the main body. Keeping the guides distinct from the parts allows manufacturer(s) to control the features/performance of the device and to sell the latter in, for instance, DIY shops as entities that are distinct from the main body and not specific to a main body. Such features include the internal frictions of the magnets on the guides or on themselves, the shape of the cross sections of the magnets and parts, etc. Fourth, Dolge's invention was designed for a specific type of applications in mind, essentially the closure of doors/panels. This means that he needed an additional specific device to rotate one of the magnets inside the parts.

Only some embodiments of the current proposal would require additional device(s), and not necessarily of the same type as the one described in Dolge's invention. For instance, embodiments such as the one described in Figure 10 do not require any kind of additional device. On the contrary, embodiment such as the one described in Figure 5 can require additional external device, such as a screwdriver, in order to rotate magnet B (2) inside parts A and B (6 and 7).

3.3.2 Internal guides By definition an internal guide goes through the magnets (1 & 2) and acts on the internal edges of the magnets. In practice, an internal guide is typically a shaft around which the magnets slide and, if required, rotate.

The principle of an internal guide is illustrated in Figure 4. In this figure, the guide is a shaft (8 & 9) that goes through the magnets (1 & 2). It is represented as a cross section similar to the one described in column 2 (c2) of Figure 1. The circular arrow represents the rotation of the magnets with respect to each others (i.e. not with respect to the shaft). In both rows (rl & r2) the parts (8 & 9) are aligned. In row 1 (rl) the alignment is locked. In row 2 (r2) the alignment is unlocked. In the example described in Figure 4, the parts are locked when the magnets are pulled towards each others. It could have been the opposite by moving away from magnet A (1) the junction of parts A and B (8 and 9).

4 Examples

This proposal can be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure is thorough and complete, and fully convey the scope of the proposal to those skilled in the art.

4.1 Example 1

This section describes an example of embodiment of the external guides described in section 3.3.1. This is why the two parts A and B are referenced by the same numbers as in Figure 3, i.e. 6 & 7. This example is illustrated in Figure 5, Figure 6 and Figure 7. Figure 5 and Figure 6 represent the principle of the BIPAROMAG push-pull device described in this example while Figure 7 discusses a possible application of such a device. Figure 5 and Figure 6 also illustrates the type of devices that could be manufactured and sold in, for instance, DIY shops as entities to be inserted (e.g. screwed, glued etc...) into a main body, regardless of what the main body can be.

Figure 5 is a perspective view of the device in which parts A and B (6 & 7) are represented as see-through parts. The dashed lines represent the hollow internal volumes of the see-through parts when the latter are not filled with a magnet. The side circular arrow represents the rotation of the magnets with respect to each others, i.e. not with respect to the parts. The top circular arrow represents the rotation of part B (7) around magnet B (2).

The North and South of the magnetic dipole axes on magnets A and B (1 & 2) are not represented, unlike in Figure 1, in order not to overload the figure.

In this example the two parts A and B (6 & 7) are two tubes. Magnet A (1) cannot slide in part A (6) but may rotate in part A (6). Magnet B (2) does rotate and slide both in part A (6) and part B (7). When the two parts A and B (6 & 7) are aligned then magnet B (2) can be inserted into parts B (7) and A (6). If magnet B (2) is let free to rotate inside both parts A and B (6 & 7) then magnet A (1) and magnet B (2) will rotate relatively to each others so that both magnets are pulled towards each others. The magnetic pull will maintain magnet B (2) inside both parts (6 & 7) thus locking the alignment of the two parts. In addition, part B (7) can freely rotate around magnet B (2) and relatively to part A (6). This is illustrated in row 1 (rl) of Figure 5.

If magnet B (2) is rotated relatively to magnet A (1) then the magnetic force will be reversed and magnet B (2) will be pushed away from magnet A (14. In order to unlock the alignment, magnet B needs to get out entirely of part A (6). The magnetic force can be sufficient to push magnet B (2) out of part A (6). If not then at least one of the extremities of magnet B (2) will be out of part B (7). This property will allow the removal of magnet B (2) out of part A (6) by grabbing, by hand or with a tool, the extremity of magnet B (2) and by pulling magnet B (2) out of part A (6). Once magnet B (2) is fully out of part A (6) the alignment of the two parts is unlocked. This is illustrated in row 2 (r2) and row 3 (r3) of Figure 5. In row 2 and row 3 the two see through parts A and B (6 & 7) are misaligned. In row 2 the misalignment is executed as a sheer movement. In that case preventing magnet A (1) to rotate in part A (6) is an option. In row 3 it is executed as a folding movement, as if the two parts were attached by a hinge (not represented). In that case part A and part B (6 & 7) are linked together; i.e. they will rotate together around magnets A and B (1 & 2). In that case, magnet A (1) needs to be free to rotate in part A (6); otherwise part B (7) will not be able to rotate around magnet B (2). This implies that to rotate magnet B (2) relatively to magnet A (1), the rotation of magnet A (1) needs to be blocked, somehow (e.g. with a screwdriver, or by sealing it in a bigger structure etc...), when magnet B (2) rotates.

It is worth noting that the hinge can rotate around one of the parts if, for instance, part A (6) is made of two coaxial cylinders. The internal cylinder can rotate inside the external cylinder that is attached to part B (7) by the hinge. Thus part B (7) and the external cylinder rotate together. Part B (7) rotates around magnet B (2) while the external cylinder rotates around the internal cylinder. Magnet A (1) is inside the internal cylinder. It can be prevented from rotating inside the internal cylinder without compromising the rotation of part B (7) around magnet B (2).

If part A and part B (6 & 7) are not attached by a hinge, as in row 2 (r2) of Figure 5, then depending on how the device is used part B (7) can slide on magnet B (2) and away from part A (6) up to the point where part B (7) can fall off magnet B (2). If this is the case then one way of maintaining part B (7) around magnet A and B (1 & 2) is to add a head at one of the extremities of magnet B (2). The pull magnetic force combined with the head will trap part B (7) between part A (6) and the head. This is described in Figure 6. Figure 6 is similar to Figure 5 except that magnet B (2) has a flat head. However, such a head is not necessary if part B (7) is prevented from sliding by means that are external to the device. Such a case is illustrated in Figure 7.

Figure 7 represents the two side panels and the pivoting door of a piece of furniture that can be used, typically, as a shoe cabinet. In this figure, the device described in row 2 (r2) of Figure 5 is used as the hinge of the door. All parts are see-through parts except the magnets that are black. The dashed lines represent the hollow internal volumes of the see through parts when the latter are not filled with a magnet. Column 1 (ci) represents a side view of the door and of the see through panels (11). Column 2 (c2) represents a view inside the cabinet, from the back of the cabinet.

One part B (7) is fixed inside and across each see-through wind (10) of the door and one part A (6)is fixed inside each see-through panel that face each others (11). In row 1 (rl) the door is moved into position; i.e. the two pairs of parts A and B (6 and 7) are aligned. Once done two magnets B (2) are inserted into the two parts B (7). There, they are attracted by the magnets A (1) and moved into their respective parts A (6). The magnetic pull keeps the magnets B (2) inside parts A (6) and B (7). Once done each pair of magnet A (1) and magnet B (2) cannot rotate relatively to each others unless forced to. However, each part B (7) can rotate around its respective magnet B (2). This allows the door to pivot; i.e. the BIPAROMAG device acts as a hinge. In rows 2 (r2) and 3 (r3), the door is respectively closed and opened.

If magnet B (2) is forced to rotate with respect to magnet A (1) (e.g. with a screwdriver) then the magnetic force will be reversed and magnet B (2) can be pulled out of part A (6) and the door can be removed.

4.2 Example 2

This section describes another example of embodiment of the external guides described in section 3.3.1. This is why the two parts A and B are referenced by the same numbers as in Figure 3, i.e. 6 & 7. This example is illustrated in Figure 8 and Figure 10. Figure 8 represents the principle of the BIPAROMAG push-pull device described in this example while Figure 10 discusses a possible application of such a device. Figure 8 also illustrates the type of devices that could be manufactured and sold in, for instance, DIY shops as entities to be inserted (e.g. screwed, glued etc...) into a main body, regardless of what the main body can be.

Figure 8 is a perspective view of the device in which parts A and B (6 & 7) are represented as see-through parts. The dashed lines represent the hollow internal volumes of the see-through parts when the latter are not filled with a magnet. The circular arrow represents the rotation of the magnets relatively to each others as well as the rotation of the parts relatively to each others. The North and South of the magnetic dipole axes on magnets A and B (1 & 2) are not represented, unlike in Figure 1, in order not to overload the figure.

In this example the two parts are two tubes of which one extremity is sealed. Magnet A (1) cannot rotate or slide in part A (6). Magnet B (2) can rotate in part A (6) but cannot rotate in part B (7). Magnet B (2) can slide in both part A and B (6 & 7). When the two parts are aligned and rotated appropriately relatively to each others, magnet B (2), initially fully lodged inside part B (7), is attracted by magnet A (1) and slides towards the latter. Once the motion is over, magnet B (2) straddle part A (6) and part B (7) thus locking the alignment of the two parts. This is illustrated in row 1 (rl) of Figure 8. If part B (7) is now rotated relatively to part A (6) then magnet B (2) is also rotated relatively to magnet A (1) thus leading to a reversion of the magnetic force direction between the two magnets.

Consequently, magnet B (2) is pushed back inside part B (7); thus unlocking the alignment of the two parts by allowing the latter to move in a sheer movement. This is illustrated in row 2 (r2) of Figure 8.

Depending on how the device is used part B (7) can slide on magnet B (2) and away from part A (6) up to the point where part B (7) can fall off magnet B (2). If this is the case then one way of maintaining part B (7) around magnet A and B (1 & 2) is to give magnet B (2) a conic shape, as described in Figure 9, with the largest base inside part B (7). With such a shape, when magnet B (2) is attracted by magnet A (1) magnet B (2) will also pushes part B (7) towards part A (6); thus preventing part B (7) to fall off magnet B (2). However, such a system is not necessary if part B (7) is prevented from sliding by means that are external to the device. Such a case is illustrated in Figure 10.

Figure 10 represents the top-down view of a toilet roll holder. In this figure the device described in Figure 8 is used to keep aligned the bar holding the toilet roll in a toilet roll holder (7) with the frame of the toilet roll holder (6). All parts are see-through parts except the magnets that are black. The dashed lines represent the hollow internal volumes of the see-through parts when the latter are not filled with a magnet. The circular arrow represents the rotation of the see-though bar (7)/magnet B (2) relatively to the see-through frame (6)/magnet A (1). In column 1 (ci) and column 2 (c2) the alignment of the bar and of the frame are, respectively, locked and unlocked. The bold double headed arrow in c2 represents the motion of the bar (7) relatively to the frame (6).

Magnet A (1) is inside the frame (6) that, subsequently, acts as part A. Magnet B (2) is inside the bar that, subsequently, acts as part B (7); alternatively, as already discussed in section 3.3.1, part A (6) and B (7) as showed in Figure 8 can also exist as such, i.e. as entities distinct from the main body to be inserted (e.g. screwed or glued) into, respectively, the frame and the bar, or vice versa. When the bar (7) is moved between the frame (6), both magnets B (2) are attracted by magnets A (1) (if they have the appropriate relative orientation).

Consequently, they move inside the frame (6) and lock the alignment of the bar with the frame. This is illustrated in column 1 (ci). Afterwards, a rotation of the bar (7) relatively to the frame (6) reverses the magnetic force and magnets B (2) is pushed back inside the bar (7) thus unlocking the alignment and allowing the bar to be removed. This is illustrated in column 2 (c2).

Such an example illustrates how such a device, amongst other potential usages, offers a mechanism that is simple to use and to build and that allows components of a structure (e.g. toilet roll holder, scaffolding components, etc...) to be easily and quickly inserted or removed in the heart of the structure both without the need to modify other parts of the structure and while keeping the attachment mechanisms totally hidden (e.g. for aesthetic reasons).

4.3 Example 3

This section describes an example of embodiment of the internal guides described in section 3.3.2. This is why the two parts A and B are referenced by the same numbers as in Figure 4, i.e. 8 & 9. This example is illustrated in Figure 11 and Figure 12. Figure 11 represents the principle of the BIPAROMAG push-pull device described in this example while Figure 12 discusses a possible application of such a device. Figure 11 also illustrates the type of devices that could be manufactured and sold in, for instance, DIY shops as entities to be inserted (e.g. screwed, glued etc...) into a main body, regardless of what the main body can be.

Figure 11 is a perspective view of the device in which magnet B (2) is a represented as a see- through component. The dashed lines represent the hollow internal volumes of the see-through magnet when the latter is not filled with a part. The side circular arrow represents the rotation of the magnets with respect to each others, i.e. not with respect to the parts.

In this example the two parts (8 & 9) are shafts. Part A (8) goes through the middle of magnet A (1) and magnet B (2). Part A (8) does not slide inside magnet A (1) but can rotate inside magnet A (1) and/or magnet B (2). Part B (9) slides only inside magnet B (2). It can also rotate inside magnet B (2). When the two parts A and B (8 & 9) are aligned and if the relative rotation of magnets A and B (1 & 2) is such that they attract each others then magnet B (2) slides around part B (9) then around part A (8). When magnet B (2) stops moving, it straddles parts A and B (8 & 9) thus locking the alignment of the two parts. This is illustrated in row 1 (rl) of Figure 11.

If magnet B (2) is now rotated relatively to magnet A (1) then the magnetic force is reversed and magnet B (2) is pushed away from magnet A (1) so that part A (8) is no longer inside magnet B (2); thus unlocking the alignment. This is illustrated in row 2 (r2) and row 3 (r3) of Figure 11. In row 2 the misalignment is executed as a sheer movement. In row 3 it is executed as a folding movement, as if the two parts were attached by a hinge (not represented). Note that the hinge should be able to go inside magnet B (2). In addition, a spherical hinge would allow a folding in all the directions.

Figure 12 represents a device that can be used, for instance, to quickly fold or unfold a table attached to a wall/panel. Magnet A (1) is attached or inserted inside the wall/panel while part B (9) and magnet B (2) is part of the table frame. Note that the hinge can be a BIPAROMAG hinge as described in section 4.1. In column 1 the two parts are aligned and the alignment is locked. They are unlocked in column 2 (c2) and 3 (c3). Column c3 shows part B (9) folded relatively to part A; note that part A is hidden inside magnet A (1) or virtual (note that the hinge (12) can be considered as part of part A).

The two parts are attached by a hinge (12) as in row 3 (r3) of Figure 11. However, magnet A (1) has a rectangular cross section and 2 sets of 2 magnetic dipole axes. One of the dipole axes of each set is parallel to the axes of the shafts. Such dipole axes are used to push and pull magnet B (2). The other dipole axis of each set is perpendicular to the previous one and is parallel to the plan that is perpendicular to the axis of rotation of the hinge. This allows magnet B (2) to be attracted by the bottom surface of magnet A (1) (see Figure c3 of Figure 12). This can prevent the shaft from dangling (or falling back if folded upward), which can be an advantage in some circumstances; note that the higher the strength of the magnetic force between the magnet A and B (1 & 2) when folded, the less likely the shaft will dangle or fall back.

4.4 Example 4

As mentioned in section 3.2, the proposal described in this patent exploits the two extreme distances, between the magnets, which are reached at the end of the push and pull motions. The previous sections provide examples of such exploitation as rotating joints or alignment locking mechanisms. This section illustrates how such binary distance can also be used as a switch (e.g. mechanical or electrical switch).

In that example the motion of magnets A and B (1 & 2) are controlled by the same guide, here an external guide. Thus when the magnets are pulled towards each others the switch is in one position and when the magnets are pushed away from each others the switch is in the other position. Figure 13 represents the principle of the BIPAROMAG push-pull device described in this example while Figure 14 discusses a possible application of such a device.

Figure 13 is a perspective view of the device in which the single external guide (13) is represented as see-through parts. The dashed lines represent the hollow internal volume of the see-through guide that is not filled with a magnet. The circular arrow represents the rotation of the magnets relatively to each others. The North and South of the magnetic dipole axes on magnets A and B (1 & 2) are not represented, unlike in Figure 1, in order not to overload the figure.

In this example the guide (13) is a tube of which one extremity is closed. Magnet A (1) can rotate but not slide in the guide (13). Part B cannot rotate but can slide in the guide (13). It is the rotation of magnet A (1) relatively to the guide (13), and subsequently to magnet B (2), that is going to control the position of magnet B (2) in the guide (13), i.e. the switch position. Magnet B (2) can then act as a mechanical switch if it is connected to an external device via, for instance, a hole in the guide or another magnet located outside the guide. It can also act as an electrical switch. Such latter use is developed below.

Figure 14 illustrates an electrical switch. It represents a cross section identical to Figure 3 and Figure 4. The circular arrow represents the rotation of the magnets relatively to each others. In this figure, magnet B (2) is electrically conductive. In addition there are two physically separated conducting rings (14 and 15) that are located inside the wall of a non-conducting guide (13). One ring is connected to one side of an electrical system, here a DC generator (16) and a lamp (17), while the other ring is connected to the other side of the electrical system. If magnet B (2) is pulled toward magnet A (1), as described in row 2 (r2), then the electrical system is off because the conducting magnet B (2) touches only one of the two rings (14). It is on otherwise, as described in row 1 (rl), because the conducting magnet B (2) connects the two rings (14 & 15). Since the magnetic force naturally attracts the two magnets together this means that the electrical system will be switched on only if an external force is maintained on magnet A (1) to repel magnet B (2); i.e. the system will be switched off as soon as the external force is gone thus leaving magnet A (1) free to rotate and to attract magnet B (2). The magnetic ring can be positioned differently to obtain the opposite result (i.e. ON when pulled and OFF when pushed). This can be used, for instance, as safety devices.