PATENT DOCUMENT

Publication Number: US-9007157-B2
Application Number: US-201213597250-A
Country: US
Kind Code: B2

Title: Magnetic assembly

Abstract:
A magnetic assembly for use in a housing of an electronic device can include a first and a second magnet and a magnetic shield. The magnetic shield can reduce magnetic flux density from the first and the second magnets that can appear on the outside of the housing. A magnetic hinge assembly can include magnets configured to correlate with the first and second magnets. The magnetic hinge can magnetically attach to the housing by cooperating with the first and second magnets with magnets that can be included in the magnetic hinge.

Claims:
What is claimed is: 
     
       1. A multi-state magnetic assembly carried by a housing of an electronic device and operable to magnetically attach an object having a triggering magnetic element to the housing, the multi-state magnetic assembly comprising: a first magnet and a second magnet each having a first surface having a shape in accordance with an interior surface of the housing and that together are capable of providing a magnetic field at an exterior surface of the housing; a magnetic attractor block between the first and the second magnets that reduces the magnetic field at the exterior surface of the housing preventing formation of a magnetic circuit that is suitable for magnetically attaching the object to the housing; and a magnetic shield formed of a ferrous material having a first surface attached to the interior surface of the housing and a second surface having a shape in accordance with the first surfaces of the first and second magnets and attached thereto, wherein a triggering magnetic field provided by the triggering magnetic element at or near the exterior surface of the housing interacts with the magnetic field causing formation of the magnetic circuit through the housing that is suitable for magnetically attaching the object to the housing. 
     
     
       2. The multi-state magnetic assembly as recited in  claim 1 , wherein the magnetic circuit that is suitable for magnetically attaching the object to the housing comprises the triggering magnetic field and the magnetic field interaction to oversaturate the magnetic shield. 
     
     
       3. The multi-state magnetic assembly as recited in  claim 1 , wherein the first surface of the magnetic shield has a shape in accordance with the interior surface of the housing. 
     
     
       4. The multi-state magnetic assembly as recited in  claim 1 , wherein the magnetic attractor block is further configured to reduce magnetic repulsion between the first and the second magnets when the first and second magnets comprise the same magnetic polarity. 
     
     
       5. The multi-state magnetic assembly as recited in  claim 1 , further comprising a magnetic shunt formed of ferrous material that is disposed on a second surface opposite the first surface of at least one of the first and the second magnets. 
     
     
       6. The multi-state magnetic assembly as recited in  claim 5 , wherein the magnetic shunt redirects at least some of the magnetic field away from the second surface and towards the interior surface of the housing. 
     
     
       7. The multi-state magnetic assembly as recited in  claim 1 , wherein the multi-state magnetic assembly is one of a plurality of multi-state magnetic assemblies attached to the interior surface of the housing. 
     
     
       8. The multi-state magnetic assembly as recited in  claim 7 , wherein the plurality of multi-state magnetic assemblies cooperate to magnetically attach the object to the exterior surface of the housing at a pre-determined location and orientation. 
     
     
       9. The multi-state magnetic assembly as recited in  claim 1 , wherein the object is an accessory device. 
     
     
       10. The multi-state magnetic assembly as recited in  claim 9 , wherein the accessory device is a protective cover comprising a single piece flap pivotally connected to the triggering magnetic element. 
     
     
       11. The electronic device as recited in  claim 1 , wherein the electronic device is a tablet device. 
     
     
       12. An electronic device having a housing, comprising: a multi-state magnetic unit carried at an interior surface of the housing of the electronic device and operable to magnetically attach an object having a triggering magnetic element to an exterior surface of the housing at a predetermined location and orientation, the multi-state magnetic unit comprising: a magnetic assembly having a surface having a shape in accordance the interior surface of the housing and capable of providing a magnetic field at the exterior surface of the housing, a magnetic attenuator attached to the magnetic assembly that reduces the magnetic field at the exterior surface of the housing thereby preventing formation of a magnetic circuit that is suitable for magnetically attaching the object to the housing, and a magnetic shield formed of a ferrous material having a first surface attached to the interior surface of the housing and a second surface having a shape in accordance with the surface of the magnetic assembly and attached thereto, wherein a triggering magnetic field provided by the triggering magnetic element at or near the exterior surface of the housing interacts with the magnetic field such that the magnetic circuit that is suitable for magnetically attaching the object to the electronic device is formed through the housing. 
     
     
       13. The electronic device as recited in  claim 12 , wherein the magnetic assembly comprises a first magnet and a second magnet each having a first surface having a shape in accordance with an interior surface of the housing. 
     
     
       14. The electronic device as recited in  claim 12 , wherein the magnetic attenuator comprises a ferrous material. 
     
     
       15. The electronic device as recited in  claim 12 , further comprising a magnetic shunt formed of ferrous material that is disposed on a second surface opposite the surface of the magnetic assembly. 
     
     
       16. The electronic device as recited in  claim 15 , wherein the magnetic shunt redirects at least some of the magnetic field away from the second surface and towards the interior surface of the housing. 
     
     
       17. The electronic device as recited in  claim 12 , wherein the multi-state magnetic unit is one of a plurality of multi-state magnetic units attached to the interior surface of the housing. 
     
     
       18. The multi-state magnetic assembly as recited in  claim 17 , wherein the plurality of multi-state magnetic units cooperate to magnetically attach the object to the exterior surface of the housing at the pre-determined location and orientation. 
     
     
       19. The multi-state magnetic assembly as recited in  claim 12 , wherein the electronic device is a tablet device.

Description:
FIELD OF THE DESCRIBED EMBODIMENTS 
     The described embodiments generally relate to portable electronic devices. More particularly, the present embodiments describe various releasable attachment techniques well suited for portable electronic devices. 
     BACKGROUND 
     Recent advances in portable computing includes the introduction of hand held electronic devices and computing platforms along the lines of the iPad™ tablet manufactured by Apple Inc. of Cupertino, Calif. These handheld computing devices can be configured such that a substantial portion of the electronic device takes the form of a display used for presenting visual content leaving little available space for an attachment mechanism that can be used for attaching an accessory device. 
     Conventional attachment techniques generally rely upon mechanical fasteners that typically require at least an externally accessible attaching feature on the electronic device to mate with a corresponding attaching feature on the accessory device. The presence of the external attaching feature can detract from the overall look and feel of the handheld computing device as well as add unwanted weight and complexity as well as degrade the appearance of the hand held computing device 
     Therefore, a mechanism for releasably attaching together at least two objects is desired. 
     SUMMARY OF THE DESCRIBED EMBODIMENTS 
     This paper describes various embodiments that relate to a system and apparatus for releasably attaching an accessory to an electronic device. 
     A multi-state magnetic assembly suitable for releasably attaching an accessory device to a housing of an electronic device can include a first magnet, with a surface shaped to conform with an interior surface of the housing and providing a first magnetic field and having a first polarity, a second magnet with a surface shaped to conform to an interior surface of the housing providing a second magnetic field and having a second polarity and a magnetic attractor block positioned between the first and the second magnets where the attractor block can reduce a magnetic flux density at an exterior surface of the housing. The multi-state magnetic assembly can also include a magnetic shield made from a ferrous material having a first surface attached to the interior surface of the housing and having a second surface attached to the first and second magnets. The second surface of the magnetic shield can have a shape conforming to the surface shapes of the first and second magnets. In an inactive state, the first magnetic shield in cooperation with the magnetic attractor block can maintain a first magnetic flux density at the outer surface of the housing below a value that is capable of adversely affecting magnetically sensitive device. In an active state, a second magnetic flux density is maintained at the outer surface of the housing that exceeds a value being suitable for forming a magnetic attachment. 
     A magnetic attachment system can include a non-ferrous housing, a first magnetic assembly near a first edge of a housing, the magnetic assembly comprising a first and a second shaped magnet where each magnet can be arranged in a particular polarity orientation and each magnet can provide a magnetic field, a magnetic attractor block positioned between the first and the second magnets where the magnetic attractor block can reduce magnetic flux density at the outer surface of the housing, and a magnetic shield positioned between the first and second magnets and the housing. The magnetic attachment system can include a magnetic hinge assembly including a first group of magnets arranged to correlate with the polarity of the first and second magnets in the magnetic assembly. The first group of magnets can provide a third magnetic field. In an inactive state, the magnetic flux density value at an exterior surface of the housing can be less than an amount that can affect a magnetically sensitive device. In an active state, the third magnetic field is brought into proximity to the first and the second magnetic fields, wherein the magnetic fields operate to provide a magnetic flux density value at the exterior surface of the housing suitable for providing a magnetic attachment between the magnetic hinge assembly and the housing. 
     A portable electronic device can include a housing and a multi-state magnetic attachment system. The multi-state magnetic attachment system can include a magnetic sub-assembly that can include a first magnet with a first surface that can be shaped to conform to an interior portion of the housing and provide a first magnetic field. The magnetic sub-assembly can also include a second magnet having a first surface shaped to conform to the interior portion of the housing and provide a second magnetic field. The multi-state magnetic attachment system can also include a magnetic shield attached to the first and the second magnets and having a shape that also conforms to the interior portion of the housing and a magnetic hinge assembly that can include a third and a fourth magnet providing a third and a fourth magnetic fields. In an inactive state, the magnetic shield can affect magnetic flux from the first and the second magnetic fields such that a magnetic flux density value at an exterior surface of the housing is less than an amount that can substantially affect a magnetically sensitive device. In an active state, the third and fourth magnetic fields are brought into proximity of the first and second magnetic fields and the first, second, third and fourth magnetic fields operate to provide a magnetic flux density at an exterior of the housing suitable for forming a magnetic attachment between the magnetic hinge assembly and the housing. 
     Other aspects and advantages of the invention will become apparent from the following detailed description taken in conjunction with the accompanying drawings which illustrate, by way of example, the principles of the described embodiments. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The described embodiments and the advantages thereof may best be understood by reference to the following description taken in conjunction with the accompanying drawings. These drawings in no way limit any changes in form and detail that may be made to the described embodiments by one skilled in the art without departing from the spirit and scope of the described embodiments. 
         FIG. 1A  and  FIG. 1B  show an electronic and a cover assembly each in perspective top views in accordance with an embodiment described in the specification. 
         FIGS. 2A and 2B  show a cover assembly and tablet device magnetically attached to each other. 
         FIGS. 3A-3C  are diagrams showing flux interactions between a magnet and surrounding elements in accordance with one embodiment described in the specification. 
         FIG. 4A  and  FIG. 4B  illustrate inactive and active states of attachment of a magnetic attachment feature between a tablet device and a cover assembly. 
         FIG. 5  is an exploded view of a magnetic assembly in accordance with an embodiment described in the specification. 
         FIG. 6  is a side view of magnetic assembly and housing in accordance with an embodiment described in the specification. 
         FIG. 7A-FIG .  7 D are simplified block diagrams of a magnetic assembly in accordance with an embodiment described in the specification. 
         FIG. 8  is a schematic diagram of a cross sectional view of a magnet in a hinge assembly magnetically coupled to housing in accordance with an embodiment described in the specification. 
         FIG. 9  is a perspective view of an exemplary housing including a plurality of magnetic assemblies in accordance with an embodiment described in the specification 
     
    
    
     DETAILED DESCRIPTION OF SELECTED EMBODIMENTS 
     Representative applications of methods and apparatus according to the present application are described in this section. These examples are being provided solely to add context and aid in the understanding of the described embodiments. It will thus be apparent to one skilled in the art that the described embodiments may be practiced without some or all of these specific details. In other instances, well known process steps have not been described in detail in order to avoid unnecessarily obscuring the described embodiments. Other applications are possible, such that the following examples should not be taken as limiting. 
     In the following detailed description, references are made to the accompanying drawings, which form a part of the description and in which are shown, by way of illustration, specific embodiments in accordance with the described embodiments. Although these embodiments are described in sufficient detail to enable one skilled in the art to practice the described embodiments, it is understood that these examples are not limiting; such that other embodiments may be used, and changes may be made without departing from the spirit and scope of the described embodiments. 
     The following description relates in general to a mechanism that can be used to attach together at least two suitably configured objects. In one embodiment, this can be accomplished without the use of conventional fasteners. Each of the objects can include an attachment feature arranged to provide a magnetic field having appropriate properties. When the attachment features are brought into proximity with each other, the magnetic fields can cooperatively interact based upon their respective properties, resulting in the objects magnetically attaching to each other in a desired and repeatable manner For example, due at least in part to the cooperative nature of the interaction of the magnetic fields, the objects can attach to each other in a pre-determined position and relative orientation without external intervention. For example, the cooperative magnetic interaction can result in the objects self-aligning and self-centering in a desired orientation. 
     The objects can remain in the magnetically attached state if and until a releasing force of sufficient magnitude is applied that overcomes the overall net attractive magnetic force. Connectors such as mechanical fasteners are not required to attach the objects together. Furthermore, to prevent undue interference to the magnetic interaction between the magnetic attachment features, at least a portion of the objects in the vicinity of the magnetic attachment features can be formed of magnetically inactive materials such as plastic or non-ferrous metals such as aluminum or non-magnetic stainless steel 
     The objects can take many forms and perform many functions. When magnetically attached to each other, the objects can communicate and interact with each other to form a cooperative system. The cooperating system can perform operations and provide functions that cannot be provided by the separate objects individually. In another embodiment, at least one device can be used as an accessory device. The accessory device can be magnetically attached to at least one electronic device. The accessory device can provide services and functions that can be used to enhance the operability of the electronic device(s). For example, the accessory device can take the form of a protective cover that can be magnetically attached to the electronic device. The protective cover can provide protection to certain aspects (such as a display) of the electronic device while enhancing the overall look and feel of the electronic device. The magnetic attachment mechanism used to magnetically attach the accessory and the electronic device can assure that the cover can only attach to the electronic device in a specific orientation. Moreover, the magnetic attachment mechanism can also assure proper alignment and positioning of the protective cover and the electronic device. 
     The protective cover can include at least a hinge portion. The hinge portion can be magnetically attached to the electronic device using a magnetic attachment feature. The hinge portion can be pivotally connected to a flap that can be placed upon a portion of the electronic device to be protected. The protective cover can include electronic circuits or other elements (passive or active) that can cooperate with electronic elements in the electronic device. 
     The remainder of this discussion will describe particular embodiments of devices that can use the magnetic attachment system. In particular,  FIG. 1A  and  FIG. 1B  show electronic device  100  presented in terms of tablet device  110  and accessory device is shown as cover assembly  120  each in perspective top views. Electronic device  100  can also take the form of other portable electronic devices. In some examples, the table device  110  can include housing  115 . Housing  115  can enclose and provide support for components of the tablet device  110 . Housing  115  can also provide support for at least a large and prominent display  116  occupying a substantial portion of a front face of the tablet device  110 . In one embodiment, housing  115  can be formed from non-ferrous material, such as aluminum, a polymer, fiber impregnated resin, non-magnetic stainless steel or the like. The display  116  can be used to present visual content. The visual content can include still images, visual, textual data, as well as graphical data that can include icons used as part of a graphical user interface, or GUI. 
     Cover assembly  120  can have a look and feel that complements that of the tablet device  110  adding to overall look and feel of tablet device  110 . Cover assembly  120  is shown in  FIGS. 1A and 1B  attached to tablet device  110  in an open configuration in which display  116  is fully viewable. Cover assembly  120  can include flap  122 . In one embodiment, flap  122  can have a size and shape in accordance with display  116 . Flap  122  can be pivotally connected to magnetic attachment feature by way of a hinge assembly (not shown). A magnetic attachment force between cover assembly  120  and magnetic attachment area  108  can maintain cover assembly  120  and tablet device  110  in a proper orientation and placement vis-a-vis flap  122  and display  116 . By proper orientation it is meant that cover assembly  120  can only properly attach to tablet device  110  having flap  122  and display  116  aligned in a mating engagement. The mating arrangement between display  116  and flap  122  is such that flap  122  covers substantially all of display  116  when flap  122  is placed in contact with display  116  as shown in  FIG. 2A  below. 
       FIG. 1B  shows tablet device  110  and cover assembly  120  rotated about 180° to provide a view of covering  160  and its relationship with cover assembly  120 . In one embodiment, covering  160  can comprise cloth. In another embodiment, covering  160  can comprise a label or other thin and relatively non-ferrous material. In one embodiment, covering  160  can act as at least a portion of a hinge assembly and allow cover assembly  120  to pivot about housing  115 . 
       FIGS. 2A and 2B  show cover assembly  120  and tablet device  110  magnetically attached to each other.  FIG. 2A  shows a closed configuration in which display  116  is fully covered by and in contact with cover flap  122 . Cover assembly  120  can pivot about covering  160  from the closed configuration of  FIG. 2A  to an open configuration of  FIG. 2B . In the closed configuration, inner layer  126  of cover assembly  120  can come in direct contact with display  116 . In a particular embodiment, inner layer  126  can be formed of a microfiber material. 
       FIGS. 3A-3C  are diagrams showing magnetic flux interactions between a magnet  302  and surrounding elements in accordance with an embodiment described in the specification.  FIG. 3A  shows magnet  302  disposed next to a section of housing  115 . In one embodiment, housing  115  can be a non-ferrous material allowing magnetic flux to easily penetrate housing  115 . Unfortunately, amounts of magnetic flux that can appear outside housing  115  can exceed a predetermined amount such that the magnetic flux  304  (shown as flux lines) can become a nuisance. For example, if a magnetic flux density related to magnetic flux  304  becomes greater than a threshold, then adverse effects can occur on magnetically sensitive devices such as credit cards, mechanical watches, magnetic compasses or the like. 
     Point P can represent a point on the outside of housing  115 . The magnetic flux density measured at point P should be less than a threshold B threshold , where B threshold  can represent a magnetic flux density value below which magnetically sensitive devices (such as a magnetic strip on a credit card) can remain substantially unaffected. As shown in  FIG. 3A , magnetic flux  304  is not impeded or reduced by housing  115 , (especially when housing  115  is non-ferrous). In one embodiment, housing  115  thickness D may not provide enough distance between point P and magnet  302  such that the magnetic flux density can be reduced to an amount less than B threshold . 
       FIG. 3B  shows magnet  302  and housing  115  with magnetic shield  306  positioned between housing  115  and magnet  302 . In one embodiment, magnetic shield  306  can be attached to magnet  302  with an adhesive  308 . Magnetic shield  306  can be a thin ferrous material that can attract and contain magnetic flux from magnet  302  by offering a low resistance flux path for magnetic flux, particularly when compared to the resistance of a magnetic flux path in air. In one embodiment, material for magnetic shield  306  can be any ferrous material. In another embodiment, magnetic shield  306  can be a ferrous material with a relatively high magnetic permeability such as low carbon steel or Mu metal (an alloy of nickel, steel and molybdenum) or any other technically feasible material. In one embodiment, magnetic shield  306  can be a thickness T such that the magnetic shield  306  in conjunction with thickness D of housing  115  can reduce magnetic flux density at point P to an amount less than B threshold . In one embodiment, magnetic flux  304  can be substantially or partially contained within magnetic shield  306 . In yet another embodiment, magnetic flux  304  can saturate magnetic shield  306 . 
       FIG. 3C  shows magnet  302 , magnetic shield  306  and housing  115 . Adhesive  308  can attach magnetic shield  306  to magnet  302 . In this figure, a second magnet  310  is positioned adjacent to the outside of housing  115 . Magnet  302  and magnet  310  can be attracted together, despite reduced magnetic flux  304  appearing outside housing  115 . In one embodiment, magnetic flux  304 , although reduced by magnetic shield  306 , can still pass through housing and interact with magnet  310 . Thus, when magnet  310  is brought into proximity of magnet  302 , magnet  302  and magnet  310  can attract each other as illustrated here. 
     In one embodiment,  FIG. 3B  can illustrate an inactive state when cover assembly  120  is not pivotably attached to housing  115  of tablet device  110 .  FIG. 3C  can illustrate an active state when cover assembly  120  is pivotably attached to housing  115  by a magnetic attraction between magnet  302  within housing  115  and magnet  310  included in cover assembly  120 . 
       FIG. 4A  and  FIG. 4B  illustrate inactive and active states of attachment of a magnetic attachment feature  400  between tablet device  110  and cover assembly  120 .  FIG. 4A  shows magnetic attachment feature  400  in an inactive attachment state. Magnet  302  can be attached to magnetic shield  306  that can be positioned adjacent to housing  115  of tablet device  110 . Magnetic shield  306  of thickness T can attract and contain or partially contain magnetic flux from magnet  302  by offering a low resistance path for magnetic flux to travel compared to the resistance path for magnetic flux through the air. 
     Cover assembly  120  can include second magnet  310  located next to covering  160 . Since housing  115  is separated from cover assembly  120 , magnetic flux  304  from magnet  302  can be contained, or partially contained in magnetic shield  306 . In the inactive state, a large separation distance between housing  115  and covering  160  can prevent magnetic attraction between magnet  302  and magnet  310 . In one embodiment, some magnetic flux  304  can be present on an outer surface of housing  115 . 
       FIG. 4B  shows magnetic attachment feature  400  in an active state. Housing  115  can be placed in close proximity to cover assembly  120 , more particularly to covering  160 . In the active attachment state, magnetic flux  312  from magnet  310  and magnetic flux  304  from magnet  302  can interact and allow magnet  310  and magnet  302  to attract each other. In the active attachment state, magnets  302  and  310  can create a magnetic coupling between cover assembly  120  which includes covering  160  and housing  115 . In one embodiment, cover assembly  120  can be pivotably couple to housing  115  through the magnetic attachment feature  400  while the magnetic attachment feature  400  is in the active attachment state. In one embodiment, the magnetic shield  306  may not affect a level of attraction from the perspective of a user. 
       FIG. 5  is an exploded view of magnetic assembly  500  in accordance with an embodiment described in the specification. Magnetic assembly  500  can include a first magnet  502 , a second magnet  504  and an attractor block  506  positioned between first and second magnets  502  and  504 . In one embodiment, attractor block  506  can be a formed from a ferrous material and can reduce the magnetic flux density at a point on the surface of housing  115 . Polarization option  1   520  is shown in  FIG. 5  where magnet  502  can be attracted to magnet  504 . 
     In another embodiment, attractor block  506  can allow magnet  502  and magnet  504  to be positioned in proximity to each other when a polar configuration of magnets  502  and  504  is such that magnetic poles within magnet  502  and magnet  504  repel each other. Polarization option  2   530  and polarization option  2   532  show two exemplary orientations when magnet  502  and magnet  504  can repel each other from their ends. 
     In one embodiment, magnetic shield  508  can formed from a ferrous material and can be attached to magnets  502 ,  504  and attractor block  506  with adhesive  510 . Adhesive  510  can be pressure sensitive adhesive, a thermally curable adhesive, a rigid or semi-rigid epoxy, a urethane adhesive or any other technically feasible adhesive. Magnetic assembly  500  can also include a rear shield  512  coupled to magnets  502  and  504 , disposed on a side of magnets  502  and  504  in opposition to magnetic shield  508 . In one embodiment, rear shield  512  can be formed from a ferrous material. In another embodiment, rear shield  512  can be formed from a non-ferrous material. In some arrangements, rear shield  512  can provide structural support. If the rear shield is formed from ferrous material, then rear shield can reduce magnetic flux from magnets  502  and  504  that may interfere with some operations of other components such as a compass and the like. In one embodiment, rear shield  512  can be attached to magnet  502  and magnet  504  with adhesive  514 . In one embodiment, adhesive  514  can be similar to adhesive  510 . 
       FIG. 6  is a side view  600  of magnetic assembly  500  and housing  115  in accordance with an embodiment described in the specification. Magnetic assembly  500  can include magnets  502 ,  504 , magnetic shield  508  and rear shield  512 . Adhesive  510  can attach magnetic shield  508  to magnets  502  and  504 . Adhesive  514  can bond rear shield  512  to magnets  502  and  504 . In the inactive state, magnetic flux density measured at point P can be less than B threshold  as described above in conjunction with  FIGS. 3A-3C . 
     At least one portion of magnets  502  and  504  can be shaped to closely match or conform to a portion of housing  115 . Matching the shape of magnets  502  and  504  to housing  115  can enable the positioning of magnets  502  and  504  to be relatively close to an inside edge of housing  115 . In one embodiment, magnets  502  and  504  can conform relatively closely to housing  115  and can reduce any gaps between magnets  502  and  504  and any external magnets that can be included in a cover assembly  120  (not shown) in order to maximize a magnetic force between magnets  502  and  504  with magnets in cover assembly  120 . Since magnetic shield  508  can be relatively thin, compared to housing  115  and magnets  502  and  504 , magnetic shield  508  can be shaped to conform to housing  115 , magnets  502  and  504  or both. 
       FIG. 7A-FIG .  7 D are simplified block diagrams  700  of magnetic assembly  500  in accordance with an embodiment described in the specification.  FIG. 7A  in particular shows an attractor configuration with attractor block  506  positioned between magnet  502  and magnet  504 . In one embodiment, attractor block  506  can be formed from a ferrous material. Magnet  502  can have a magnetic north pole positioned as shown. Magnet  504  can have a relatively opposite polar orientating a magnet south pole positioned as shown. In this configuration, attractor block  506  can reduce flux density at a surface of housing  115 .  FIG. 7B  is a similar attractor configuration with simply swapping positions of the north and south poles. 
       FIG. 7C  shows a buffer configuration with attractor block  506  positioned between magnets  502  and  504 , however in this example, magnets  502  and  504  are configured to have a similar polar orientation. As shown, the magnetic north pole of magnet  502  is adjacent to the magnetic north pole of magnet  504 . In this configuration, magnet  502  can seek to repel magnet  504  on its end with a repulsive magnetic force. Attractor block  506  can be configured to allow magnet  502  to be positioned near magnet  504  despite repulsive magnetic forces. In one embodiment, an attractor block  506  can have thickness Y such that magnets  502  and  504  can couple to the ferrous attractor block  506  reducing or eliminating repulsive magnetic forces between magnets  502  and  504 .  FIG. 7D  shows another embodiment of a buffer configuration, but in this embodiment magnetic south pole of magnet  502  is adjacent to magnetic south pole of magnet  504 . 
       FIG. 8  is a schematic diagram of a cross sectional view  800  of a magnet  810  adjacent to covering  160  magnetically coupled to housing  115  in accordance with an embodiment described in the specification. More particularly,  FIG. 8  shows a simplified magnetic attachment system  840  comprising covering  160  and a housing  115  operating in an active state. In the active state, magnets  810  that can be positioned within or on covering  160  can be attracted to one or more magnetic assemblies  500  located with housing  115  causing covering  160  to magnetically attach to housing  115 . In one embodiment, housing  115  can include display  116 . In the active state, magnetic flux from magnet  810  and magnets  502  and  504  can over saturate magnetic shield  508  and allow a magnetic attraction between magnets  810  and magnets  502  and  504 . 
     Magnetization vectors can indicate a magnetic force or attraction from a magnet. Magnet  810  in covering  160  can have a magnetization vector M 1 , while magnetic assembly  500  can have a magnetization vector M 2 . Positioning of magnet  810  and magnetic assembly  500  can configure magnetization vectors M 1  and M 2  to be relatively normal to the covering  160  and the housing  115  respectively. An additional magnetic shield  850  can be disposed on a portion of magnet  810 . In one embodiment, additional magnetic shield  850  can reduce magnetic flux in an area beyond magnetic shield  850 . 
       FIG. 9  is a perspective view  900  of a housing  115  including a plurality of magnetic assemblies  500  in accordance with an embodiment described in the specification. In this example, housing  115  can be a housing for tablet computer  110 . The plurality of magnetic assemblies  500  can be arranged along an axis (linearly in this example) of housing  115 . As described above, the first and second magnets included in each magnetic assembly  500  can have a polarity orientation. Exemplary polar orientation is shown in  FIG. 7A-FIG .  7 D. In other embodiments, other polarity orientations can be possible. 
     Magnetic assemblies  500  can be configured to have varying polarity orientations to help assure proper alignment of cover assembly  120  attached to housing  115  through covering  160  and magnetic attachment area  108  (shown with a dashed line). Magnetic assembly  902  can be one embodiment of magnetic assembly  500  configured in a buffer assembly, such as  FIG. 7A  or  FIG. 7B . In turn, each magnetic assembly included in housing  115  can have one of the four polar orientations shown in  FIG. 7A-FIG .  7 D. Magnetic assembly  904  can be configured to have a polar orientation of  FIG. 7B , magnetic assembly  906  can be configured to have a polar orientation of  FIG. 7C  and magnetic assembly  908  can be configured to have a polar orientation of  FIG. 7D . 
     Arranging particular configurations of magnetic assemblies  902 - 908  within housing  115  can help control alignment of cover assembly  120  with respect to housing  115 . Magnets included in or next to covering  160  can be configured to correlate with the polarity orientations of magnets in magnetic assemblies  902 - 908 . For example, to couple with magnets in magnetic assembly  902 , magnets can be arranged in a configuration similar to magnetic assembly  908  and included in covering  160  at a position in covering  160  to substantially align cover assembly  120  to housing  115 . Similarly, complimentary magnetic arrangements for other magnetic assemblies  904 - 908  in housing  115  can be provided in covering  160 . The magnets within or adjacent to covering  160  can couple to magnets in magnetic attachment area  108  such that the position of covering  160  can be determined, at least in part, by the configuration of magnet polarities and positions of magnets within covering  160 . Thus, magnets in covering  160  and housing  115  can cooperate to attach, self-align and self-center cover assembly  120  in a desired orientation. 
     The various aspects, embodiments, implementations or features of the described embodiments can be used separately or in any combination. Various aspects of the described embodiments can be implemented by software, hardware or a combination of hardware and software. The described embodiments can also be embodied as computer readable code on a computer readable medium for controlling manufacturing operations or as computer readable code on a computer readable medium for controlling a manufacturing line. The computer readable medium is any data storage device that can store data which can thereafter be read by a computer system. Examples of the computer readable medium include read-only memory, random-access memory, CD-ROMs, HDDs, DVDs, magnetic tape, and optical data storage devices. The computer readable medium can also be distributed over network-coupled computer systems so that the computer readable code is stored and executed in a distributed fashion. 
     The foregoing description, for purposes of explanation, used specific nomenclature to provide a thorough understanding of the described embodiments. However, it will be apparent to one skilled in the art that the specific details are not required in order to practice the described embodiments. Thus, the foregoing descriptions of specific embodiments are presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the described embodiments to the precise forms disclosed. It will be apparent to one of ordinary skill in the art that many modifications and variations are possible in view of the above teachings.

Metadata:
Filing Date: 20120828
Publication Date: 20150414
Grant Date: 20150414
Priority Date: 20120828
Inventors: OW FLORENCE W.
FRANKLIN JEREMY C.
Assignee: APPLE INC
CPC Classifications: [{"code": "G06F1/1626", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F2200/1634", "inventive": false, "first": false, "tree": "[]"}, {"code": "H05K9/0075", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01F7/0263", "inventive": true, "first": true, "tree": "[]"}, {"code": "G06F2200/1634", "inventive": false, "first": false, "tree": "[]"}, {"code": "G06F1/1626", "inventive": true, "first": true, "tree": "[]"}, {"code": "G06F2200/1634", "inventive": false, "first": false, "tree": "[]"}, {"code": "G06F1/1626", "inventive": true, "first": true, "tree": "[]"}]
Family ID: 50184132