Abstract:
A mechanism comprising a first component having a first magnetic part, a second component, and a third component having a second magnetic part, the third component being moveable relative to said first component in a given direction to effect connection and or disconnection of the first and second components by causing interaction of the first and second magnetic parts, wherein, when connected, the first and second components are able to move relative to one another in said given direction. The mechanism further comprising a fourth component for engagement with said first component to prevent movement of the third component relative to the first component as a result of relative movement of the first and second components, thereby to prevent unintended disconnection of the first and second components,

Description:
TECHNICAL FIELD 
       [0001]    The present invention relates to magnet fixings and connectors. 
       BACKGROUND 
       [0002]    Various magnetic fixing arrangements are described in the following documents: US2011/001025, PCT/EP2012/059870, DE145325, U.S. Pat. No. 3,596,958 
       SUMMARY 
       [0003]    According to a first aspect of the present invention there is provided a mechanism comprising a first component having a first magnetic part, a second component, a third component having a second magnetic part, the third component being moveable relative to said first component in a given direction to effect connection and or disconnection of the first and second components by causing interaction of the first and second magnetic parts, wherein, when connected, the first and second components are able to move relative to one another in said given direction. The mechanism further comprises a fourth component for engagement with said first component to prevent movement of the third component relative to the first component as a result of relative movement of the first and second components, thereby to prevent unintended disconnection of the first and second components. 
         [0004]    The given direction may be a rotational direction. At least one of the magnetic parts may be moveably retained by a guide such that said interaction of the magnetic parts causes a movement of the magnetic part along the guide to a position in which the third component is mechanically secured to the first component. Said first magnetic part may be moveable relative to the first component, under the effect of the second magnetic part, in order to engage said fourth component with said first component. The moveable magnetic part may be moveable in a direction that is substantially parallel or substantially perpendicular to the axis of rotation. 
         [0005]    Other aspects of the present invention are set out in the appended claims. 
         [0006]    In the first, and other aspects where relevant, the third or fourth component may slide inside or around the first and second components and, when connected to the first component, that third or fourth straddles the first and second component. One of the magnetic parts may slide inside or around the other magnetic part, and the mechanism further comprises a fifth component acting as a guide for the sliding magnetic part such that, when the magnetic parts are engaged, the sliding magnetic part straddles the fifth component and the other magnetic part. 
         [0007]    In the first, and other aspects where relevant, there may be provided a further mechanical lock for locking and unlocking the first and third components with respect to one another by said relative motion in the given direction. The mechanical lock may comprises one or more of:
       clip and clip engagement features formed on the first and third components; interengaging rails formed on the first and third components;   further magnetic components moveable in a direction different from a direction in which one of said magnetic parts is able to move.       
 
         [0010]    In the first, and other aspects where relevant, one or more of the magnetic parts may comprise multiple oppositely oriented dipoles. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]      FIG. 1  to  FIG. 2  illustrate the general principle of linear push-pulls; 
           [0012]      FIG. 3  illustrates the general principle of restricted linear push-pulls; 
           [0013]      FIG. 10  to  FIG. 11  illustrate the general principle of multiple fixing surfaces; 
           [0014]      FIG. 4  illustrates the general principle of perpendicular push-pull longitudinal blocking; 
           [0015]      FIG. 5  to  FIG. 9  illustrate the principle of rail longitudinal blocking; 
           [0016]      FIG. 12  to  FIG. 15  illustrate the use of push-pull in the case of sliding platforms; 
           [0017]      FIG. 16  to  FIG. 22  illustrate the multi-layer principle; 
           [0018]      FIG. 23  to  FIG. 30  illustrate various possible multilayer embodiments; 
           [0019]      FIG. 31  to  FIG. 32  illustrate various embodiments of possible alternative to the multilayer principle; 
           [0020]      FIG. 33  to  FIG. 38  illustrate various possible embodiments of the multi-part principle; and 
           [0021]      FIG. 39  illustrates the multilayer embodiment of  FIG. 25 , but with alternative numbering. 
       
    
    
     DETAILED DESCRIPTION 
       [0022]    For the sake of clarification,  FIG. 39  illustrates a multilayer embodiment of  FIG. 25  (described further below), but with an alternative numbering system. The following description of the embodiment will be helpful in understanding the description of  FIG. 25  and also of further embodiments. 
         [0023]    The illustration above the dotted line in  FIG. 39  is an exploded view of the embodiment. It illustrates five components, namely a fixed first part  100 , e.g. which might be fixed to a wall, having a first fixed magnetic part  101 . This first magnetic part  101  is located within a recessed socket  113 , with the magnetic part being fixed within the guide. A second component  102  is a hollow cylinder configured to accommodate a third part  103  and a fourth, locking part  104 , where the locking part is also cylindrical and is located, substantially coaxially, between the second and third parts. The third part comprises a central passage  105  having a generally square cross-section. A second magnetic part  106  is secured within this passage  105 . 
         [0024]    The embodiment comprises a fifth part  107  having an enlarged head  108  and a shaft  109  have a square cross-section such that the shaft can be located within the passage  105  of the third part. Rotation of the fifth part  107  therefore results in rotation of the third part  103  relative to the first part  100 . The first and second magnetic parts each comprise a single dipole magnet, the magnetic axes being aligned perpendicular to the rotational axis of the first and second parts. 
         [0025]    The second, third, fourth and fifth parts are assembled into a single unit  110  that can be engaged with the first part  100 . When the assembled unit and the first part are brought together, a pair of lugs  111  projecting from the end of the fourth part  104  locate within respective recesses  112  formed in the first part. The engagement of the lugs with the recesses prevents the fourth part from rotating relative to the first part. By rotating the head of the fifth part  107 , a user is able to rotate the third part  103  relative to the first part  100  (and the fourth part  104 ). This action can be used to align the magnetic dipoles of the magnetic part  101 ,  106  such that a magnetic attraction occurs. As a result, the second magnetic part is pulled towards the first magnetic part  101 , in turn pulling the third part  103  towards and into engagement with the first part  100 . The third part slides within the fourth part  104  during this step. 
         [0026]    In order to prevent the assembled unit  110  being pulled away from the first part  100 , overcoming the magnetic attraction force, a set of latches  114  project from the end of the third component  103  and penetrate into a generally circular recess  115  formed in the first component  100 . Rotation of the third component  103  causes these latches to locate behind respective lips formed around the circumference of the recess  115 , preventing the assembled unit from being pulled away from the first part. 
         [0027]    In this configuration, as has already been noted, the fourth component  104  cannot rotate relative to the first component  100 . However, the second component  102  is free to rotate around the fourth component  104 . Moreover, the third component  103  can be rotated in a counter-direction in order to rotate the second magnetic component  106  and release the latches  114  from behind the holding lips. Such rotation will cause a repulsion of the two magnetic components, allowing the assembled unit  110  to be removed from the first component  100 . 
         [0028]    It will be apparent that the advantage of the embodiment of  FIG. 39  is that the fourth part  104  effectively decouples the second part  102  from the third part  103 . Rotation of the second part has no effect on the third part and in particular will not cause any rotation, and therefore release of, the third part from the first part. 
         [0029]    An modification to this mechanism replaces the recesses  115  with recesses that are configured to snap-in the latches  114  during attachment of the unit  110 . The mechanism is such that, as the unit is brought into close proximity with the first part  100 , the magnetic parts self-align, rotating the third part  103  to a position in which the latches  114  are properly aligned with the recesses. The magnetic force is sufficient to pull the third part  103  towards the first part, causing the latches  114  to snap into place behind respective lips. When the third part is subsequently rotated to a position in which the magnetic parts are mis-aligned and the latches are no longer caught by the lips, the repulsion force pushes the third and first parts apart. 
         [0030]    Hereafter, the term “push-pull” designates a device that is made of first ( 1 ) and second ( 2 ) magnetic components moveable with respect to each other, both having magnetic properties so that relative rotational or linear motion, hereafter called the “actuation motion”, causes one of the components, hereafter it will always and arbitrarily be the first magnetic component ( 1 ), to move between a locking position in which that first /component ( 1 ) straddles two guides, ( 3 ) and ( 4 ), made of antimagnetic material (i.e. made of a material that is magnetically neutral such as plastic, wood, aluminium etc . . . ), and an unlocking position in which that does not straddle the two guides. The straddling mechanically prevents the two guides, ( 3 ) and ( 4 ), to move in a folding motion or in a motion that is not parallel to the direction of motion of the first component ( 1 ) when it moves from a locking to an unlocking position. Hereafter, this latter motion is called the “locking/unlocking motion”. Such push-pulls offer various advantages such as aesthetics (e.g. the mechanisms can be totally hidden from view), haptic, rapidity/simplicity of use, safety, cost reduction (e.g. by reducing structure assembling/disassembling times), entertainment, novelty/fashion, improve quality, etc . . . . The trade domains that can benefit from such push-pulls devices include toys, furniture, bathroom equipment, boxes (e.g. jewellery cases), bags, clasps, scaffolding, building frames, panel frames, item holders, fastening devices, lifting or pulling mechanisms etc . . . . The mechanical strength that prevents the guides to move relatively to each others, in a sheer or folding motion, is a function of the material that is used to straddle the guides. This material can be the material that is used to make the magnet. It can also be the one that is attached to the magnets (e.g. to wrap the magnets) and that moves with the magnets. Thus “magnetic component” designates both the magnet(s) and their surrounding material. All push-pulls described in this document can be manufactured first and, later, be integrated (e.g. screwed, glued etc . . . ) into other parts; they can be bespoke or standardised and potentially sold in shops as stand alone products. They can also be manufactured at the same time as the other parts so that no later integration is required. The magnetic force can be used only to lock or to unlock the system (as opposed to lock and to unlock the system). In that latter case, an additional force is required to unlock or lock the system, respectively. This additional force can be the same force as the one used by the actuation motion or a separate one. If a separate force is used then the latter must be strong enough to move ( 1 ) from the locking (unlocking) position to the unlocking (locking) position and weak enough not to prevent the magnetic force between ( 1 ) and ( 2 ) to move the first component ( 1 ) from its unlocking (locking) position to its locking (unlocking) position. This means that the actuation motion of the ( 1 ) and ( 2 ) only needs to modulate the magnitude of the magnetic force, i.e. not its direction. This separate force can be generated by a spring or by another magnet/paramagnetic material acting as a spring. If the actuation motion force is used then the locking/unlocking motion of ( 1 ) is mechanically actuated. This means that ( 1 ), ( 2 ), ( 3 ) and ( 4 ), are shaped so that the actuation motion will move ( 1 ) on sections of ( 4 ) and/or ( 2 ) that are inclined so that the actuation motion results in an increase of the distance between ( 1 ) and ( 2 ) (e.g. see  FIG. 2  for a linear motion). In that case the magnetic force does not have to be modulated or its direction reversed. The magnetic properties of ( 1 ) and ( 2 ) depend on whether the magnetic force needs to be modulated or its direction changed. If the magnetic force direction is reversed then ( 1 ) and ( 2 ) can both contain magnets with an adequate orientation of their magnetic poles. Alternatively, one component contains a magnet and the other one a patchwork of paramagnetic and diamagnetic materials. If the force is merely modulated then, typically, one component can contain a magnet and the other one a patchwork of paramagnetic and antimagnetic materials. Note that a paramagnetic material is only attracted when in the presence of an externally applied magnetic field, that a diamagnetic material is repelled by magnetic fields and that an antimagnetic material is impervious to the effect of a magnetic field. Linear actuation motion means that to unlock the push-pull, ( 1 ) slides linearly relatively to ( 2 ) and parallel to an orientation that is not parallel to the locking/unlocking motion orientation. Rotational actuation motion designates a linear actuation motion with a first component ( 1 ) path wrapped around an axis that is not parallel to the linear actuation motion orientation. This wrapping axis becomes the axis of rotation and, depending on the embodiments, can go or not through ( 1 ). Hereafter, the terms “parallel rotational” and “perpendicular rotational” refer to rotational push-pulls where the rotational axis is, respectively, parallel and not-parallel to the locking/unlocking motion direction. Note that for parallel rotational push-pulls, the ability of ( 1 ) to rotate relatively to ( 3 ) can be a function of its linear position along ( 3 ) as illustrated in  FIG. 13  of PCT/EP2012/059870. The guiding can be “internal”, “external” or “mixed” for both linear and rotational actuation motions. The guiding is said to be “internal” if the guide penetrates, partially. or totally, ( 1 ) and/or ( 2 ). It is said to be “external” if the magnetic component penetrates, partially or totally, the guide. The guiding is said to be “mixed” if it is internal on a section of the first component ( 1 ) path and external on another section; see PCT/EP2012/059870 for examples of internal, external and mixed guiding for rotational push-pulls. In addition ( 1 ) and/or ( 2 ) may or not slide relatively to ( 3 ) and/or ( 4 ) during the execution of the actuation motion. In all the figures below the following convention is used: the surfaces of the guides and of the parts are totally or partially white while the surfaces of the material with magnetic properties are all black.  FIG. 1  illustrates the principle of a linear push-pull (i.e. a push-pull with a linear actuation motion). The linear actuation and locking/unlocking motions of ( 1 ) are, respectively, parallel to the Y and)( directions. Guide ( 4 ) contains at least  2  magnets. The orientations the magnetic dipoles of all the magnets are parallel to ( 1 ) one, i.e. to the X direction. However, the directions of the magnetic dipoles inside ( 4 ), alternate along the Y direction. Thus, in FIG.  1 . a  the push-pull is locked. In FIG.  1 . b  ( 1 ) moved in the Y direction and is now in front of a magnet of ( 2 ) of which magnetic dipole direction is opposite to the previous one. Therefore ( 1 ) is now pushed away from ( 2 ) and the push-pull is unlocked; i.e. ( 3 ) and ( 4 ) can now move parallel to the Z orientation in opposite directions. Note that, in this illustration, ( 3 ) does not move relatively to ( 4 ) in the Y direction during the actuation motion although it could (e.g. see  FIG. 3 ); only ( 1 ) does. Note that other magnetic configurations producing the same inversion of the magnetic force as a result of a linear actuation motion of the first component are possible. For instance, the orientation of the magnetic dipoles of ( 1 ) and ( 2 ) could be perpendicular to the locking/unlocking orientation. In  FIG. 2 , as opposed to  FIG. 1 , the magnetic force direction is not reversed and the additional force is the actuation motion force. This can be seen by the bevelled shape of the duct and of the surface of ( 1 ) of which normal has one of its vector components in the Y direction. Component ( 1 ) is attracted by ( 2 ) if left free to position itself. During the actuation motion ( 1 ) is moved along the +Y axis. As a result, the bevelled shape pushes ( 1 ) outside ( 4 ); for simplicity ( 3 ) has not been represented. Hereafter, the term “Restricted Linear Push-Pull” (RLPP) applies on a linear push-pull as described above but of which ( 1 ) cannot slide relatively to ( 3 ) in a direction that is parallel to the actuation motion. The push-pull can use internal, external or mixed guiding and the magnetic components can be used to lock and unlock the push-pull as well as to lock or unlock the push-pull. Such linear push-pulls, restricted or not, can be used, for instance, to attach a panel of a dolls house on a main frame, a removable tray on the legs of baby highchairs (when not use as a table), a lid on a box, etc . . .  FIG. 3  illustrates the basic principle of Restricted Linear Push-pull. It is similar to  FIG. 1 . The key difference between  FIG. 1  and  FIG. 3  is that in  FIG. 3  ( 1 ) can slide relatively to ( 3 ) only in directions that are parallel to the locking/unlocking motion direction (i.e. the)(axis). One or more set of Restricted Linear Push-pulls can be used to interlock two parts, ( 5 ) and ( 6 ), together. Several sets are used in  FIG. 3  to  FIG. 5 . There are two sets in  FIG. 3  that share ( 2 ).  FIG. 4 ,  FIG. 5 ,  FIG. 10  and  FIG. 38  involve Restricted Linear Push-pulls. In order to simplify these  FIGS. 1 ) and ( 2 ) as well as ( 3 ) and ( 4 ) are not represented in details. They are symbolised by black rectangles. Each black rectangle can represent the first ( 1 ) or second ( 2 ) magnetic component. In practice, for the Restricted Linear Push-pull to work, if a black rectangle is ( 1 ) then the opposite black rectangle, on the other part, must be ( 2 ); or vice versa. In addition, for these figures, sub-figures A, B and C represent, respectively, the case when parts ( 5 ) and ( 6 ) are attached, i.e. when the Restricted Linear Push-pulls are locked, when the parts have been moved relatively to each others in a direction that is parallel to the actuation motion direction (at this stage the Restricted Linear Push-pulls are unlocked) and, finally, when the parts have been moved in the direction that is not parallel to both the actuation and locking/unlocking motion directions. Hereafter, the term “Hook Longitudinal Blocking” designates a push-pull of which ( 1 ), when locked, is prevented from moving in a direction that is parallel to the locking/unlocking motion by hooks. In addition, these hooks automatically release their grip during the actuation motion and do not prevent the locking of the push-pull. These hooks can be located on ( 1 ) and grab ( 2 ) and/or ( 4 ). They can also be located on ( 2 ) and/or ( 4 ) and grab ( 1 ). Such hooks can move or bent to allow the locking of the push-pull but need to remain in their gripping position when locked. In order to achieve the latter, they can use the elastic properties of the material (as in  FIG. 3 ), springs or magnets acting as springs.  FIG. 3  is a perspective view of an example of embodiment of mechanical Hook Longitudinal Blocking system for a linear push-pull (the principle would remain the same for rotational push-pulls). The protruding parts ( 7 ), at the top and bottom of the first magnetic components ( 1 ), pushes up or down the hooks ( 8 ) when the push-pull is being locked by moving closer the parts ( 5 ) and ( 6 ) parallel to the)(axis. Once locked, hooks ( 8 ) have grabbed the protruding part ( 7 ) and prevent the two parts, ( 5 ) and ( 6 ), to move away from each other in a direction parallel to the)(axis. However, after the actuation motion has been executed, the protruding parts ( 7 ) are now in the grooves ( 9 ) and parts ( 5 ) and ( 6 ) can move relatively to each other in a direction parallel to the X axis. 
         [0031]    Hereafter, the term “Perpendicular Push-Pull Longitudinal Blocking” designates a system that is made of two parts, ( 5 ) and ( 6 ), which are mechanically coupled by two sets of at least one push-pull of any kinds, the locking/unlocking motion directions of the push-pulls of one set are not all parallel to the ones of the second set and the actuation motion directions of the push-pulls of both sets are all parallel. Note that some push-pulls of one set may share their second magnetic component ( 2 ) with some push-pulls of the second set.  FIG. 4  is a perspective view of an example of embodiment of such a Longitudinal Blocking system in the particular case of a Restricted Linear Push-pull. Two sets of  3  Restricted Linear Push-pulls are mounted on two perpendicular surfaces of parts ( 5 ) and ( 6 ). The locking/unlocking motion direction is parallel to the Z axis for one set of push-pull and to the X axis for the second set. Thus, when locked, the two parts, ( 5 ) and ( 6 ), can only move relatively to each other in directions that are parallel to the actuation motion direction (Y axis). Note that Perpendicular Push-Pull Longitudinal Blocking for rotational push-pulls has been introduced in PCT/EP2012/059870. 
         [0032]    Hereafter, the term “Rail Longitudinal Blocking” designates push-pulls of which guides ( 3 ) and ( 4 ) are shaped so that they interlock by sliding relatively to each others in a direction that is not parallel to the locking/unlocking motion, hereafter called the interlocking motion direction, so that, when locked, they hook each others in a way that they cannot move in a direction that is parallel to the locking/unlocking motion direction and so that, when locked, the straddling of ( 3 ) and ( 4 ) by ( 1 ) prevents ( 3 ) and ( 4 ) to move in opposite directions parallel to the interlocking motion orientation. Guides ( 3 ) and ( 4 ) disengaged by executing the actuation motion and by moving them in opposite directions parallel to the interlocking motion orientation (or to one of them if there are more than one possible interlocking motion orientations).  FIG. 5  to  FIG. 9  are perspective views of examples of embodiments of such a longitudinal blocking system. 
         [0033]    In these figures, the black circular arrows represent the actuation motions, the straight white arrows represent the relative motions of the parts when unlocked and the black surfaces represent ( 1 ) and ( 2 ). At least one of the guides has a section shaped as a rail ( 10 ).  FIG. 5  involves Restricted Linear Push-pulls. In  FIG. 5  the sets of Restricted Linear Push-pulls are positioned on both the internal ( 11 ) and external ( 12 ) surfaces of the rail ( 10 ). This is not mandatory. A set on the internal surface ( 11 ) of part ( 5 ) and on the external surface ( 12 ) of part ( 6 ), or vice versa, would work as well. The actuation and locking/unlocking motion directions are parallel to, respectively, the Y and X axes.  FIG. 6  to  FIG. 9  involve rotational push-pulls and describe a distribution of a plurality of guides ( 3 ) or ( 4 ). These guides can have a  1 ,  2  or  3  dimensional distribution. The distribution is  1 D, e.g. as in  FIG. 6  and  FIG. 7 , if they are distributed on a straight or not line inside a part ( 13 ). It is  2 D, e.g. as in  FIGS. 8 , and  3 D, e.g. as in  FIG. 9 , if they are distributed on the surface of a part ( 13 ) that is respectively open (e.g. a plan) and closed (e.g. a cube or a sphere). Other embodiments do not have to consider such a distribution of guides, i.e. they can consider one guide only. In  FIG. 6  ( 1 ) can be locked at any of the guide ( 4 ) positions. FIG.  6 . a  shows the push-pull locked while FIG.  6 . b  and FIG.  6 . c  show the push-pull unlocked from opposite view points. In  FIG. 6  ( 4 ) can be circular or not. If it is circular then both components ( 1 ) and ( 2 ) can rotate relatively to ( 4 ). If both ( 4 ) and a large enough ( 1 ) are not circular (i.e. square in  FIG. 6 ) then only ( 2 ) can.  FIG. 7  is similar to  FIG. 6  but it uses internal guides as opposed to external ones. In  FIG. 7  ( 1 ) rotates around ( 3 ). It does not have to be the case as long as ( 1 ) and ( 2 ) can rotate relatively to each others. In both  FIG. 6  and  FIG. 7  component ( 2 ) moves with ( 1 ). It does not have to, as illustrated in  FIG. 8 . However, this illustrates the fact that a multi-position system does not necessarily need to have as many components ( 2 ) as there are locking positions, as it is the case for instance in  FIG. 8  and  FIG. 9  (since ( 2 ) can move with ( 1 )). In  FIG. 8  to  FIG. 9  neither ( 1 ) nor ( 2 ) can rotate inside, respectively, ( 3 ) and ( 4 ). This does not have to be the case for all embodiments. In addition, the push-pull is a parallel rotational push-pull. Other embodiments can consider linear or perpendicular rotational push-pulls. In  FIG. 8  ( 3 ) can move freely or be locked at certain locations depending on the relative orientation of ( 1 ) and ( 2 ). FIG.  8 . b  is guide ( 3 ) of FIG.  8 . a  upside down in order to show ( 1 ). In this figure, component ( 1 ) pops out of ( 3 ) as if it was attracted by ( 2 ).  FIG. 9  illustrates a  3 D multi-position system for a rotational push-pull with, respectively, internal ( 14 ) and external ( 15 ) guides. They are the equivalent of  FIG. 7  and  FIG. 8  wrapped around a cube. There could be more than one ( 2 ) on each face of the cube. In addition, if  FIG. 7  and  FIG. 8  had been wrapped around a disc or a sphere then ( 1 ) and ( 3 ) could go from one ( 2 ) to another without the need to remove them from the rail ( 10 ). 
         [0034]    Hereafter, the term “Multiple Fixing Surfaces” designates a system that comprises two parts, ( 5 ) and ( 6 ), the first part is attachable to the second part along at least two fixing surfaces, ( 16 ) and ( 17 ), and at least one of the fixing surfaces is attached to the other part by at least one push-pull.  FIG. 10  is a perspective view of an example of embodiments of “Multiple Fixing Surfaces” using Restricted Linear Push-pull with external guiding. The actuation motion and the locking/unlocking motion are parallel to, respectively, the Y and)(axes.  FIG. 11  shows various examples of how to implement part ( 5 ) as well as the diversity of the ways of interlocking parts ( 5 ) and ( 6 ). Part ( 5 ) of FIG.  11 . a  is the one used in  FIG. 10 . Note that in  FIG. 11  part ( 5 ) uses only components ( 1 ) and ( 3 ). This was only to make the figure more explicit. It could have held only components ( 2 ) or a patchwork of components ( 1 ) and ( 2 ). Multiple fixing systems are relevant for any type of push-pulls. For instance, if they were linear push-pull but not Restricted Linear Push-pulls then step B of  FIG. 10  would be replaced by a motion of ( 1 ) relative to ( 3 ) in the direction of the actuation motion; i.e. part ( 5 ) would not need to move relatively to part ( 6 ) in the actuation motion direction. 
         [0035]    Hereafter, the term “sliding platform” designates a system made of a first platform ( 18 ) and of another platform or housing ( 19 ), where ( 18 ) can hover parallel to the surface of ( 19 ) in one or more directions while still mechanically coupled to the latter and where ( 18 ) can be locked at least (e.g. see the  1 D distribution discussed in the “rail longitudinal blocking” section above) at one given location, relatively to ( 19 ), by a push-pull of any kind. The mechanical coupling can be realised in various ways. A part ( 20 ) can slide inside guide(s) ( 21 ) or be attached at the extremity of an articulated arm ( 22 ). It is fixed on one of the two platforms while ( 21 ) or ( 22 ) are attached to the other platform. Guides ( 3 ) or ( 4 ) can be located in ( 18 ) and ( 19 ) only; i.e. not in ( 20 ), ( 21 ) or ( 22 ). They can be also located in ( 20 ) and ( 21 ) or ( 22 ) only, i.e. not in ( 18 ) or ( 19 ), or one can be located both in ( 18 ) or ( 19 ) and the other one in ( 20 ), ( 21 ) or ( 22 ). In any case the degree of freedom of motion of part ( 20 ) relatively to ( 21 ) or ( 22 ) must be such that it does not prevent the actuation motion to take place.  FIG. 12  to  FIG. 15  describe examples of embodiment of the sliding platform principle. In these figures, ( 18 ) and ( 19 ) are a circular drawer and its housing. This embodiment uses two rotational push-pulls located on a central axis ( 23 ) going through the centre of the circular surface of the drawer. This central axis ( 23 ) is parallel to the locking/unlocking motion and is also part ( 20 ). There are two push-pulls at the top and bottom of ( 23 ); there could be only one.  FIG. 13  to  FIG. 15  are see-through top down views of  FIG. 12  that exposes the various parts and their dynamic.  FIG. 13  to  FIG. 14  involves guides ( 21 ) while  FIG. 15  involves an articulated arm ( 22 ). In these figures, ( 21 ) and ( 22 ) are not telescopic although they could be. Such telescopic systems could be used, for instance, to move drawer ( 18 ) fully out of ( 19 ). In  FIG. 13  guides ( 21 ) do not rotate around a pivot. In that case guides ( 21 ) will force ( 18 ) to move in predetermined straight lines in one or more directions; i.e.  3  in the figure. This means that  FIG. 13  can represent either  3  drawers ( 18 ), positioned one above each others, which have been pulled in  3  different directions and/or the  3  different directions ( 18 ) can be pulled out.  FIG. 14  illustrates the case when ( 18 ) slide in one or more guides ( 21 ) that can rotate around a pivot ( 24 ). This means that ( 18 ) can be pulled in various directions but always in the same direction as ( 21 ). In  FIG. 12  to  FIG. 15  the single headed black circular arrow indicates the actuation motion. The double headed white circular arrows indicate, when unlocked, the rotation of ( 18 ) around ( 20 ) 423 ). The double headed black circular arrows indicate the rotation of the guides ( 21 ) relatively to a pivot ( 24 ). The double headed straight white arrows indicate the direction of the motion of ( 20 )/( 23 ) relatively to its guide ( 21 ). The small white circle illustrates the position of ( 20 )/( 23 ). The dotted circle ( 24 ) illustrates the pivots ( 24 ) of ( 21 ) and ( 22 ).  FIG. 12  to  FIG. 15  describe rotational push-pulls but linear push-pulls could be used as well. A linear push-pull could be used, for instance, for a non-circular drawer. When locked, the push-pull would prevent the drawer to move, for instance, in all the directions but the actuation motion one. To move the drawer, the drawer needs to be pulled (as opposed to be rotated in  FIG. 12  to  FIG. 15 ), first, in the actuation motion direction to unlock the push-pull and then move in whatever directions that are allowed. Note that mechanisms pushing ( 18 ) out of ( 19 ), more or less strongly, when unlocked, can be added for convenience of use. 
         [0036]    The term Multi-Layers Push-pull designates a system made of at least four parts. If a first part, hereafter called the sliding part ( 25 ), moves relatively to a second part, hereafter called the reference part ( 26 ) then the sliding part ( 25 ) can also move by friction a third part, hereafter called the dragged part ( 27 ), in the same direction as its direction of motion. To prevent this a fourth part, hereafter called the additional part ( 28 ), which cannot be dragged by friction by the sliding part ( 25 ), is inserted between the sliding part ( 25 ) and the dragged part ( 27 ). Such an additional part ( 28 ) acts as a mechanical insulation layer between the sliding ( 25 ) and the dragged parts ( 27 ). Some of these four parts can be parts ( 1 ), ( 2 ), ( 3 ) and/or ( 4 ) of a push-pull of any kind. In that case, ( 28 ) will prevent unwanted locking/unlocking of the push-pull. Indeed, ( 26 ) and ( 27 ) can be, for instance, ( 1 ) and ( 2 ) of any kind of push-pull. Consequently, if the orientation of the motion of ( 25 ) is identical to the orientation of the actuation motion and if ( 28 ) is absent then, through friction, the motion of ( 25 ) can trigger a relative motion of ( 1 ) and ( 2 ) parallel to the actuation motion orientation thus potentially resulting in a unwanted locking/unlocking of the push-pull. Note that the issue is the same if ( 27 ) is a guide relatively to which ( 1 ) cannot slide parallel to the actuation motion. The sliding part ( 25 ) can be, for instance, ( 3 ) and/or ( 4 ).  FIG. 16  to  FIG. 22  are schematics of possible embodiment principles of such layered systems. They are all based on a linear actuation motion. However, as already mentioned above, the logic is the same for a rotational actuation motion. In all these figures, ( 25 ) slides parallel to the Y direction, the locking/unlocking motion is parallel to the X direction, the actuation motion is parallel to the Y direction and when the push-pull is locked ( 1 ) and ( 2 ) cannot move relatively to each others parallel to the Z direction. In  FIG. 16  ( 28 ) is an extension of or is attached to ( 26 ) and slides underneath ( 27 ) in the)(direction. In  FIG. 17  ( 28 ) is not an extension of or attached to ( 26 ) and may or not slide underneath ( 27 ). The push-pulls is locked in FIG.  16 . a  and FIG.  17 . a  and unlocked in FIG.  16 . b  and FIG.  17 . b .  FIG. 18  and  FIG. 19  are similar to, respectively,  FIG. 16  and  FIG. 17 . The difference is that ( 28 ) has been shaped as a hook ( 29 ) so that when the push-pull is locked ( 25 ) is prevented to move parallel to the Z direction, i.e. a direction that is not parallel to both the actuation motion and the locking/unlocking motion directions.  FIG. 20  is similar to  FIG. 16  and  FIG. 21  and  FIG. 22  are similar to  FIG. 17 . The difference is that the normals of the friction surfaces are parallel to the Z and)(directions for, respectively.  FIG. 16  to  FIG. 19  and  FIG. 20  to  FIG. 22 . Note that in  FIG. 20  to  FIG. 22  part ( 28 ) could have hooked shapes, similar to the ones described in  FIG. 18  and  FIG. 19 .  FIG. 23  to  FIG. 30  are perspective views of example of embodiments of some of the principles illustrated in  FIG. 16  to  FIG. 22 . In these figures the white and black circular arrows describe the rotation, respectively, of ( 25 ) when locked and of the actuation motion. The straight white arrows represent the relative motions of the parts when unlocked.  FIG. 23  to  FIG. 27  are examples of embodiments of the principle described in  FIG. 17 .  FIG. 28 ,  FIG. 29  and  FIG. 30  are examples of embodiment of the principle described in, respectively.  FIG. 19 ,  FIG. 16  and  FIG. 22 . The system described in  FIG. 23  involves a Restricted Linear Push-pull while the systems described in  FIG. 24  to  FIG. 27  and in  FIG. 28  to  FIG. 30  involve, respectively, parallel and perpendicular rotational push-pulls.  FIG. 23  to  FIG. 30  involves external guides only; although for  FIG. 25  the guiding could also be considered as internal since ( 1 ) slides along the rotating guide ( 43 ). The logic would be the same for mixed and or internal guides. All the systems described in  FIG. 24  to  FIG. 30  act primarily as pivots.  FIG. 24  and  FIG. 25  could be used as the hinge of a door, such as the pivoting doors of a shoe cabinet (e.g. see PCT/EP2012/059870 for more details on the shoe cabinet).  FIG. 26  to  FIG. 27  could be used, for instance, as a hidden hinge of a door, a panel, a lid or a handle etc . . .  FIG. 28  could be used to couple two pivoting poles of the same diameter.  FIG. 29  and  FIG. 30  could be used to attach parts (e.g. a pedal) on a crank. The system is unlocked in FIG.  23 . a  and locked in FIG.  23 . b . FIG.  24 . a  described the assembled and locked system. FIG.  24 . b  and FIG.  24 . c  represent the relative motion of the parts, before or after they are locked, from two different view points. For  FIG. 25 ,  FIG. 28 ,  FIG. 29  and  FIG. 30  sub-figures A. B. C and D describe, respectively, an exploded view of all the independent parts, the relative motion of the assembled parts relatively to each others and two cross sections of the system showing the motion of ( 1 ) and of ( 25 ) to go from a locked to an unlocked push-pull configuration. Note that in  FIG. 23  to  FIG. 30 , but  FIG. 29 , ( 28 ) can rotate relatively to ( 25 ) but not to ( 26 ), because of the protrusion ( 30 ) that penetrates the recess ( 31 ). Such a shaping of ( 28 ) and of ( 26 ) so that when the push-pull is locked the two parts are mechanically coupled is a typical way of preventing ( 28 ) to be dragged by friction by ( 25 ). Note that when ( 25 ) is also ( 3 ) then, ( 1 ) can but does not have to straddle ( 3 ) and ( 4 ) as long as ( 28 ) straddles ( 3 ) and ( 4 ); i.e. ( 28 ) becomes an extension of ( 1 ).  FIG. 29  is different because ( 28 ) and ( 26 ) are permanently coupled.  FIG. 29  is also a “Multi-parts system” (see below). The holes ( 32 ) in  FIG. 29  and  FIG. 30  are designed to receive additional magnets to keep ( 1 ) retracted when the push-pull are unlocked although springs could be used for the same effect. The strength of these additional magnets must be strong enough to keep ( 1 ) retracted but weak enough not to prevent ( 1 ) to be attracted by ( 2 ). In addition in  FIG. 24 , ( 28 ) is only pushed by ( 1 ) (while it is pushed and pulled in  FIG. 23  and  FIG. 25 ) and the edge ( 33 ) on ( 28 ) has been introduced to prevent ( 25 ) to slide out when the system is locked. Such an edge is not mandatory and can be useless for some applications such as the hinges of the revolving door of a show cabinet (e.g. see PCT/EP2012/059870 for more details on the shoe cabinet). In some circumstances, it can be required to be able, on request, to mechanically couple ( 25 ) and ( 27 ) so that ( 27 ) moves with ( 25 ). Indeed, in  FIG. 24  and  FIG. 25 , ( 1 ) is rotatable because one of its extremities is accessible (e.g. to a screwdriver). It is not the case for the system described in  FIG. 26  to  FIG. 27 . This means that to unlock the push-pull, the relative rotation of ( 1 ) and ( 2 ) requires that ( 25 ) and ( 1 ) be mechanically coupled. The latter are mechanically coupled only when the coupling part ( 35 ) is inserted inside ( 25 ) and straddles ( 25 ) and groove ( 34 ). FIG.  26 . a  describes all the part of the system. FIG.  26 . b  shows the rotation of the hinge when the coupling part ( 35 ) has been inserted, i.e. when the push-pull is in the process of being unlocked. If ( 35 ) had not been inserted then part ( 25 ) could rotate freely without unlocking the push-pull. FIG.  26 . c  illustrates the use of the hinge to attach a rotating panel, such as a door, to a frame.  FIG. 27  illustrates what happens inside ( 25 ) when ( 35 ) has been inserted. The coupling part ( 35 ) penetrates groove ( 34 ) located inside ( 1 )/( 27 ). When ( 3 )/( 25 ) rotates relatively to ( 4 ), ( 35 ) rotates with it and forces ( 1 )/( 27 ) to rotate inside ( 28 ) as described in FIG.  27 . a  and FIG.  27 . b . Once fully rotated, ( 1 )/( 27 ) and ( 28 ) are pushed up by ( 2 ). The coupling part ( 35 ) can slide inside both groove ( 34 ) and cut ( 36 ) in order not to prevent ( 1 )/( 27 ) and ( 28 ) to fully slide out of ( 4 ) and, subsequently, to release the hinge. 
         [0037]      FIG. 31  and  FIG. 32  illustrate an alternative way to the multi-layered approach for parallel rotational push-pull. In both cases, ( 1 ) and ( 2 ) can rotate freely relatively to ( 3 ) and ( 4 ). However, when locked, ( 1 ) cannot rotate relatively to ( 4 ) because of the non circular (i.e. square in that case) sections of ( 37 ) and ( 38 ). Consequently, ( 2 ) must be able to rotate relatively to ( 4 ) to unlock the push-pull. The difference between these two figures is that ( 37 ) went through ( 3 ) during the locking process, while it did not in  FIG. 32 . In both cases, when locked, ( 3 ) can rotate freely relatively to ( 1 ) without triggering the actuation motion by friction. 
         [0038]    Hereafter, the term “Multi-parts systems” designates a system where a first part ( 39 ) is used to block the relative motion of two other parts, ( 40 ) and ( 41 ), in some directions and ( 39 ) is connected to at least one of the other parts, say part ( 40 ), by a push-pull of any kind. A multi-part push-pull that involves more than  3  parts is equivalent to two or more  3 -parts push-pulls that share at least one of their parts.  FIG. 33  to  FIG. 38  no perspective views of examples of embodiment of such a multi-part system. They show the dynamic of the system required to unlock the systems and separate the parts. The parts are fully coupled on the left sub-figures and fully separated on the right one. The middle sub-figures show intermediate steps. In these figures the straight or circular black arrows describe the actuation motion. The straight white arrows represent the relative motions of the parts when unlocked. All  FIG. 33  to  FIG. 38  but  FIG. 34  involve  3  parts.  FIG. 34  involves  4  parts: ( 39 ), ( 40 ), ( 41 ) and ( 42 ). The first part ( 39 ) needs to move relatively to the other parts for the push-pull to unlock in all figures but  FIG. 36  and  FIG. 37  as, in these latter figures, ( 1 ) or ( 2 ) can rotate relatively to guides ( 3 ) and ( 4 ). As showed in the insert of  FIG. 37 , ( 1 ) slides relatively to the rotating guide ( 43 ).  FIG. 33  and  FIG. 38  involve linear push-pulls. The push-pull is parallel rotational for  FIG. 34 ,  FIG. 36  and  FIG. 37 . It is perpendicular-rotational for  FIG. 35 . Note that in  FIG. 34  and  FIG. 35  the rotational axis does not go through ( 1 ). In all cases, the parts can be shaped and/or material with compression elasticity can be used to increase the frictions between the parts and reduce some free motion between the parts due to manufacturing tolerance between parts. In  FIG. 33  to  FIG. 35 , when the push-pull is unlocked, ( 1 ) is either in the first ( 39 ) or second ( 40 ) part. This is arbitrary; it could have been the other way around. Extremity ( 44 ) slides in both non circular openings ( 45 ) and ( 46 ) during the locking or unlocking process. When locked openings ( 45 ) and ( 46 ) are oriented in such a way that extremity ( 44 ) could slide inside ( 45 ) but not ( 46 ); thus locking all three parts.  FIG. 38  is a perspective view of an example of a special case of embodiment where the second and third parts are linked by a hinge. 
         [0039]    Restricted linear push-pulls, multi-layers and multi-part push-pulls can use “hook longitudinal blocking” systems, “rail longitudinal blocking” systems, “perpendicular longitudinal blocking” systems and or be used by “multiple fixing surface” systems. Multiple fixing surface systems can use “hook longitudinal blocking” systems, “rail longitudinal blocking” systems, “perpendicular longitudinal blocking”. Multi-layers and multi-part push-pulls. Sliding platforms can use “hook longitudinal blocking” systems, “rail longitudinal blocking” systems and/or “perpendicular longitudinal blocking systems”.