PATENT DOCUMENT

Publication Number: US-10463119-B1
Application Number: US-201615249852-A
Country: US
Kind Code: B1

Title: Band with magnetic closure mechanism

Abstract:
A band for a wearable device includes a first strap having a magnetic insert defining an array of holes, and a second strap having a magnetic protrusion configured to be at least partially disposed in a respective hole of the array of holes and to magnetically couple to the magnetic insert. A method of manufacturing a magnetic strap for a wearable device includes disposing a magnetizable insert between a first layer and a second layer, and coupling the first layer to the second layer such that the magnetizable insert is retained between the first layer and the second layer. The magnetizable insert includes a magnetizable material suspended in a polymer.

Claims:
What is claimed is: 
     
       1. A band for a wearable device, comprising:
 a first strap comprising a magnetic insert defining an array of holes; and 
 a second strap; 
 a clasp comprising a first clasp portion pivotally coupled to a second clasp portion, the first clasp portion being coupled to the second strap; and 
 a magnetic protrusion extending from a surface of the second clasp portion and being configured to be at least partially disposed in a respective hole of the array of holes and to magnetically couple to the magnetic insert; 
 wherein, when the clasp is in a closed configuration, the first strap is captured between the first clasp portion and the second clasp portion such that the magnetic protrusion is retained at least partially in the respective hole. 
 
     
     
       2. The band of  claim 1 , wherein the first strap further comprises:
 a first layer defining a first exterior surface; and 
 a second layer defining a second exterior surface opposite the first exterior surface; wherein 
 the magnetic insert is between the first layer and the second layer. 
 
     
     
       3. The band of  claim 1 , wherein the clasp comprises latching features that releasably retain the clasp in the closed configuration. 
     
     
       4. The band of  claim 1 , wherein:
 the magnetic insert comprises a polymer material having magnetized particles suspended therein; and 
 the magnetic protrusion comprises a permanent magnet. 
 
     
     
       5. The band of  claim 1 , wherein:
 the first strap extends along a longitudinal axis; and 
 the magnetic insert has a magnetic pole orientation that is substantially parallel to the longitudinal axis. 
 
     
     
       6. The band of  claim 1 , wherein:
 the first clasp portion comprises first arms with first latching features; and 
 the second clasp portion comprises second arms with second latching features, wherein, when the clasp is in the closed configuration, the first latching features engage the second latching features. 
 
     
     
       7. The band of  claim 6 , wherein the first clasp portion comprises buttons that, when operated, cause the first latching features to disengage the second latching features. 
     
     
       8. The band of  claim 1 , wherein a magnetic pole orientation of the magnetic insert faces a same direction as a magnetic pole orientation of the magnetic protrusion. 
     
     
       9. A band for a wearable device, comprising:
 a first strap comprising a magnetic insert; and 
 a second strap; 
 a clasp coupled to the second strap and comprising:
 a first clasp portion having first arms with first latching features; and 
 a second clasp portion having second arms with second latching features, the second clasp portion being pivotally coupled to the first clasp portion; and 
 
 a magnetic protrusion positioned at the second clasp portion and being configured to magnetically couple to the magnetic insert; 
 wherein, when the clasp is in a closed configuration, the first latching features engage the second latching features and the first strap is captured between the first clasp portion and the second clasp portion. 
 
     
     
       10. The band of  claim 9 , wherein:
 the first clasp portion comprises first arms with first latching features; and 
 the second clasp portion comprises second arms with second latching features, wherein, when the clasp is in the closed configuration, the first latching features engage the second latching features. 
 
     
     
       11. The band of  claim 10 , wherein the first clasp portion comprises buttons that, when operated, cause the first latching features to disengage the second latching features. 
     
     
       12. The band of  claim 9 , wherein a magnetic pole orientation of the magnetic insert faces a same direction as a magnetic pole orientation of the magnetic protrusion. 
     
     
       13. The band of  claim 9 , wherein the first strap comprises:
 a first layer defining a first exterior surface; 
 a second layer defining a second exterior surface opposite the first exterior surface; and 
 the magnetic insert between the first layer and the second layer, wherein the second layer and the magnetic insert define holes extending entirely through the second layer and the magnetic insert and to the first layer. 
 
     
     
       14. The band of  claim 9 , wherein:
 the magnetic insert comprises a polymer material having magnetized particles suspended therein; and 
 the magnetic protrusion comprises a permanent magnet. 
 
     
     
       15. A band for a wearable device, comprising:
 a first strap comprising:
 a first layer defining a first exterior surface; 
 a second layer defining a second exterior surface opposite the first exterior surface; and 
 a magnetic insert between the first layer and the second layer, wherein the second layer and the magnetic insert define an array of holes extending entirely through the second layer and the magnetic insert and to the first layer; and 
 
 a second strap comprising a magnetic protrusion configured to be at least partially disposed in a respective hole of the array of holes and to magnetically couple to the magnetic insert, wherein the magnetic insert and the magnetic protrusion each have a magnetic pole orientation that is substantially parallel to a longitudinal axis of the first strap; and 
 a clasp comprising:
 a first clasp portion coupled to the second strap; and 
 a second clasp portion pivotally coupled to the first clasp portion, wherein, when the clasp is in a closed configuration, the first strap is captured between the first clasp portion and the second clasp portion. 
 
 
     
     
       16. The band of  claim 15 , wherein:
 the first clasp portion comprises first arms with first latching features; and 
 the second clasp portion comprises second arms with second latching features, wherein, when the clasp is in the closed configuration, the first latching features engage the second latching features. 
 
     
     
       17. The band of  claim 16 , wherein the first clasp portion comprises buttons that, when operated, cause the first latching features to disengage the second latching features. 
     
     
       18. The band of  claim 15 , wherein the magnetic pole orientation of the magnetic insert faces a same direction as the magnetic pole orientation of the magnetic protrusion. 
     
     
       19. The band of  claim 15 , wherein:
 the magnetic insert comprises a polymer material having magnetized particles suspended therein; and 
 the magnetic protrusion comprises a permanent magnet.

Description:
CROSS-REFERENCE TO RELATED APPLICATION(S) 
     This application is a nonprovisional patent application of U.S. Provisional Patent Application No. 62/234,845, filed Sep. 30, 2015 and titled “Band with Magnetic Closure Mechanism,” the disclosure of which is hereby incorporated herein by reference in its entirety. 
     FIELD 
     The disclosure relates generally to wearable electronic devices, and more particularly to bands that are used to secure devices to persons or objects. 
     BACKGROUND 
     Conventional wearable devices, such as wristwatches, include bands that couple the device to a user. For example, a conventional wristwatch typically includes a band that attaches the watch to a user&#39;s wrist. Bands may be formed from various materials, such as fabric, leather, links, and the like. In order for bands to be applied to and removed from a user, bands may use clasps, buckles, or other closure mechanisms that allow the band to expand or open so that a user can apply the device to a desired body part or object, and also secure the band together (at a smaller size) to retain the device to the wearer. 
     SUMMARY 
     A band for a wearable device includes a first strap comprising a magnetic insert defining an array of holes, and a second strap comprising a magnetic protrusion configured to be at least partially disposed in a respective hole of the array of holes and to magnetically couple to the magnetic insert. The magnetic insert may include a polymer material having magnetized particles suspended therein, and the magnetic protrusion may include a permanent magnet. 
     The first strap may further include a first layer defining a first exterior surface and a second layer defining a second exterior surface opposite the first exterior surface. The magnetic insert may be between the first layer and the second layer. 
     The band may further include a clasp coupled to the second strap and comprising a first clasp portion pivotally coupled to a second clasp portion. The magnetic protrusion may extend from a surface of the second clasp portion. In a closed configuration, the first strap may be captured between the first clasp portion and the second clasp portion such that the magnetic protrusion is retained at least partially in the respective hole. The clasp may include latching features that releasably retain the clasp in the closed configuration. 
     The first strap may extend along a longitudinal axis, and the magnetic insert may have a magnetic pole orientation that is substantially parallel to the longitudinal axis. 
     A band for a wearable device may include a first strap defining a blind hole, a ferromagnetic plate disposed in the blind hole, and a second strap comprising a magnetic engagement feature configured to be at least partially disposed in the blind hole and magnetically coupled to the ferromagnetic plate. The magnetic engagement feature may include a magnet and an encasing structure surrounding at least part of the magnet. The encasing structure may be configured to engage the ferromagnetic plate when the magnetic engagement feature is disposed at least partially in the blind hole. 
     The first strap may extend along a longitudinal axis, and the magnetic engagement feature may be magnetically attracted to the ferromagnetic plate along an attraction axis that is perpendicular to the longitudinal axis. The band may further include a clasp coupled to the second strap and comprising a first clasp portion pivotally coupled to a second clasp portion. The magnetic engagement feature may extend from a surface of the second clasp portion. In a closed configuration, the first strap may be captured between the first clasp portion and the second clasp portion such that the magnetic engagement feature is retained at least partially in the blind hole. 
     The encasing structure may define an opening, and the ferromagnetic plate may be configured to be at least partially disposed in the opening when the magnetic engagement feature is disposed at least partially in the blind hole. The ferromagnetic plate may define a concave surface, and the encasing structure may define a convex surface configured to contact the concave surface when the magnetic engagement feature is disposed at least partially in the blind hole. The encasing structure may include a first component formed from a magnetic material, and a second component formed from a non-magnetic material. The non-magnetic material may be disposed over a top of the magnet such that the non-magnetic material is between the magnet and the ferromagnetic plate when the magnetic engagement feature is disposed at least partially in the blind hole. 
     The magnet may be a first magnet having a first magnetic pole orientation, and the magnetic engagement feature may further include a second magnet having a second magnetic pole orientation opposite the first magnetic pole orientation. The ferromagnetic plate may define a coupling face. When the magnetic engagement feature is disposed at least partially in the blind hole, the first and second magnetic pole orientations may be substantially perpendicular to the coupling face. 
     A method of manufacturing a magnetic strap for a wearable device includes disposing a magnetizable insert between a first layer and a second layer and coupling the first layer to the second layer such that the magnetizable insert is retained between the first layer and the second layer. The magnetizable insert may include a magnetizable material suspended in a polymer material. 
     The method may further include magnetizing the magnetizable insert such that a magnetic pole orientation of the magnetizable insert is substantially parallel to a longitudinal axis of the magnetic strap. The operation of magnetizing the magnetizable insert may be performed after the operation of coupling the first layer to the second layer. 
     The method may further include forming an array of holes through the second layer and the magnetizable insert. The operation of forming the array of holes may include forming the array of holes through the first layer, the magnetizable material, and the second layer. 
     The method may further include mixing the magnetizable material with the polymer material to form a moldable mixture, introducing the moldable mixture into a mold cavity, and curing the moldable mixture to form the magnetizable insert. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The disclosure will be readily understood by the following detailed description in conjunction with the accompanying drawings, wherein like reference numerals designate like structural elements. 
         FIG. 1  shows an example wearable device including a band. 
         FIG. 2  shows an exploded view of a strap for the band of  FIG. 1 . 
         FIG. 3  shows a partial view of the band of  FIG. 1 . 
         FIG. 4  shows a partial view of the band of  FIG. 1 . 
         FIG. 5  shows a cross-sectional view of the band of  FIG. 1  viewed along line  5 - 5  in  FIG. 4 . 
         FIG. 6  shows a detail cross-sectional view of a portion of the band of  FIG. 5 . 
         FIG. 7  shows a detail cross-sectional view of a portion of the band of  FIG. 5 . 
         FIG. 8  shows a strap for a band for a wearable device. 
         FIG. 9  shows a partial view of a band for a wearable device that includes the strap of  FIG. 8 . 
         FIG. 10  shows a cross-sectional view of the band of  FIG. 9  viewed along a line analogous to line  5 - 5  in  FIG. 4 . 
         FIG. 11  shows a detail cross-sectional view of a portion of the band of  FIG. 10 . 
         FIGS. 12A-12I  show cross-sectional views of a magnetic engagement feature. 
         FIG. 13  shows an example process for manufacturing a strap. 
     
    
    
     DETAILED DESCRIPTION 
     Reference will now be made in detail to representative embodiments illustrated in the accompanying drawings. It should be understood that the following descriptions are not intended to limit the embodiments to one preferred embodiment. To the contrary, it is intended to cover alternatives, modifications, and equivalents as can be included within the spirit and scope of the described embodiments as defined by the appended claims. 
     Wearable devices, such as watches, are typically secured to a user or to an object with a band. Some bands are composed of multiple rigid links that can articulate with respect to one another to allow the band to flex to conform to a wearer&#39;s wrist. Other bands use materials that are inherently flexible, such as fabrics, leather, polymers, or the like. Discussed herein are bands for wearable devices that use magnets and/or magnetic materials to facilitate secure coupling of the band. For example, a flexible magnetic insert with a series of holes may be incorporated in one strap of a band, and a magnetic post may be incorporated on another strap (e.g., on a clasp). The magnetic post may be magnetically attracted to the magnetic insert when the post is inserted into one of the holes in order to help retain the two straps together and to provide tactile feedback to the user indicating that the straps have been securely coupled. The mechanical engagement of the post and the hole in which the post is inserted may provide the retention force that keeps the two straps coupled together when the band is being worn. 
     The flexible magnetic insert can be incorporated into straps made of various different materials, and can be formed into many different shapes and configurations. Moreover, the flexible magnetic insert may be magnetized so that a magnetic pole orientation (e.g., a vector extending generally from a south pole of a magnet to a north pole of the magnet) is parallel with the length of the strap. The magnetic post may have a magnetic pole orientation that is parallel with (and facing the same direction as) the flexible magnetic insert so that the direction of the magnetic flux through the post and the insert is directed along the length the strap, rather than perpendicular to the length of the strap. 
     Also discussed herein are bands having ferromagnetic inserts (e.g., steel disks or plates) disposed within each of a series of holes along the length of a strap, and a magnetic engagement feature that is magnetically attracted to the inserts when the post is inserted into one of the holes. The magnetic attraction helps retain the two straps together and provides tactile feedback to the user that the straps have been securely coupled. The magnetic engagement features may include structures and/or materials that may increase the magnetic attraction between the engagement feature and the insert, and may focus, shunt, concentrate, or otherwise change the magnetic field produced by a magnet of the magnetic engagement feature. 
     In the following figures and description, similar instances of particular components or features may be designated by additional indicators appended to the element number. For example, a particular instance of a hole  112  may be designated  112 - 1 . References to an element number without any additional indicator (e.g., the hole  112 ) apply to any or all instances of that component or feature, and references to an element number with an additional indicator (e.g., the hole  112 - 1 ) apply to a particular instance of that component or feature. Moreover, any discussion related to an individual instance of a component or feature (e.g., the hole  112 - 1 ) may also apply to other instances of that component. Also, while the components and concepts are described herein with reference to wearable electronic devices, it will be understood that this is merely an example, and the components and concepts may apply equally to other objects as well, such as belts, backpack straps, tie-downs, lanyards, and the like. 
       FIG. 1  shows a wearable device  100  (also referred to as “device  100 ”). The device  100  may be any appropriate wearable device, including an electrical or mechanical wrist watch, an electronic computing device, a health monitoring device, a timekeeping device, a stopwatch, etc. The device  100  may include a housing  102  that forms an outer surface or partial outer surface and protective case for the internal components of the device  100 . The housing  102  may also include mounting features formed on opposite ends to connect a wearable band  104  (also referred to as “band  104 ”) to the housing  102 . The band  104  may include a first strap  108 , a second strap  106 , and a clasp  110  for releasably coupling the first strap  108  to the second strap  106 . The first strap  108  defines an array of holes  112  into which a protrusion on the clasp  110  may extend in order to secure the first strap  108  to the second strap  106 . Each of the holes  112  corresponds to a different size of the band  104 , allowing a wearer to select a desired band tightness. 
     The first strap  108  and the second strap  106  may be separate components (as shown in  FIG. 1 ) or they may be a single component. For example, a single length of material may pass through the housing  102  and/or through loops or other mounting structures of the housing  102  to form two distinct segments extending from opposite sides of the housing  102  (e.g., segments analogous to the first strap  108  and the second strap  106 ). 
       FIG. 2  is an exploded view of the first strap  108 . The first strap  108  comprises a first layer  200  and a second layer  204 . The first layer  200  defines a first exterior surface of the first strap  108 , and the second layer  204  defines a second exterior surface of the first strap  108  that is opposite the first exterior surface. For example, the first layer  200  may define an exterior surface that sits against or proximate a wearer&#39;s body when the device  100  is attached to the wearer, and the second layer  204  may define an exterior surface that faces away from the wearer&#39;s body when the device  100  is attached to the wearer. 
     The first and second layers  200 ,  204  (as well as the second strap  106 ) may be formed from or include any appropriate material. For example, either or both of the first and second layers  200 ,  204  may be formed from or include leather, polymer (e.g., silicone, nylon, polyurethane, liquid crystal polymer (e.g., Vectran), para-aramid (e.g., Kevlar), or the like), fabric, and so forth. The first and second layers  200 ,  204  may be formed from the same or different materials. The first strap  108  may also include other layers or components that are not shown in  FIG. 2 . For example, the first strap  108  may include reinforcing layers, adhesive layers, stitching, seams, and the like. 
     The first strap  108  also includes a flexible magnetic insert  202  (also referred to herein as “magnetic insert  202 ”). The flexibility of the magnetic insert  202  allows the band to use magnetic attraction to facilitate coupling of the first and second straps  108 ,  106 , while also allowing the straps to easily flex and conform to a wearer&#39;s body (or other object). The flexibility also permits the magnetic insert  202  to be formed into shapes and sizes that may not be feasible with rigid magnets, and allows the magnetic insert  202  to be coupled to other strap components and/or materials more easily than may be possible with rigid magnets. 
     The magnetic insert  202  may be disposed in a recess  206  in the second layer  204 , and the first layer  200  may then be disposed over the second layer  204  and over the magnetic insert  202  such that the magnetic insert  202  is disposed between the first and second layers  200 ,  204 . The magnetic insert  202  may be coupled to the second layer  204  and/or the first layer  200  with an adhesive or other bonding agent. Alternatively, the magnetic insert  202  may be held in place without being adhered to the first or second layers  200 ,  204 . For example, the first layer  200  may be sewn, glued, molded, ultrasonic welded, or otherwise securely coupled to the second layer  204 , and the magnetic insert  202  may be held between the layers as a result of the coupling between the layers. 
     The first layer  200  may define an array of holes  208  therein. The holes  208  in the first layer  200  may be configured to align with holes  210  in the magnetic insert  202 . The holes  208  in the first layer  200  and the holes  210  in the magnetic insert  202  together form the holes  112  of the first strap  108  into which a magnetic protrusion extends (as shown in  FIG. 5 , for example). As shown, the holes  208 ,  210  extend all the way through the first layer  200  and the magnetic insert  202 , respectively. However, in some cases, the holes in either or both the first layer  200  and the magnetic insert  202  may be blind holes. Moreover, while not shown in  FIG. 2 , the second layer  204  may include through-holes that align with the holes  208 ,  210 , thereby forming holes that extend through the whole thickness of the first strap  108 . 
     The flexible magnetic insert  202  may be magnetized so that it produces a persistent magnetic field. The magnetic field may have a magnetic pole orientation that is parallel to a longitudinal axis  212  of the first strap  108 . (The longitudinal axis  212  of the first strap  108  extends along the first strap  108  from an end that is coupled to the housing  102  to an end that is configured to couple to the clasp  110 .) For example, a north pole of the flexible magnetic insert  202  may be located at an end of the magnetic insert  202  that is proximate the housing  102 , and the south pole may be located at an opposite end of the magnetic insert  202 . The relative positions of the north and south poles of the magnetic insert  202  may also be swapped from that described above. In either case, a line extending from one pole of the magnetic insert  202  to the other pole may be substantially parallel with the longitudinal axis  212  of the first strap  108 . 
     The flexible magnetic insert  202  may be formed from and/or include any appropriate materials. For example, the magnetic insert  202  may comprise a flexible matrix (e.g., a polymer such as silicone, nylon, polyurethane, or any other appropriate material) with magnetized particles suspended therein. The magnetized particles may be particles of neodymium iron boron, samarium cobalt, alnico, ceramic, or the like. The magnetized particles may be magnetized before or after being suspended in the flexible material. For example, unmagnetized particles of a magnetic material may be incorporated in a polymer material, and then the polymer material with the unmagnetized particles may thereafter be molded or otherwise processed to form an unmagnetized flexible insert. The unmagnetized flexible insert is then exposed to a magnetic field, thereby magnetizing the particles and producing a magnetic insert that produces a persistent magnetic field. Alternatively, magnetized particles may be introduced into the polymer material prior to molding or forming the magnetic insert  202 . The magnetic pole orientations of the magnetic particles may be aligned in a common direction, for example, by exposing the polymer material to a magnetic field during the molding or forming process. 
     The first strap  108  may include components or structures that surround all or parts of the walls and edges that define the holes  112 . For example, the edges and/or walls that define the holes  112  may be covered with a sealing material, such as a polymer material that may be sprayed-on, brushed-on, or otherwise applied to the first strap  108 . As another example, an eyelet or grommet structure may be disposed in the holes  112  and/or around the edges that define the openings of the holes  112 . As yet another example, the edges and/or walls that define the holes  112  may be stitched. As yet another example, the magnetic insert  202  may be coated with a second material that encapsulates the magnetic insert  202  and forms the rest of the first strap  108 . The second material may be sprayed, overmolded, dip-coated, shrink-wrapped, or the like. Such components or seals may help strengthen the holes  112 , prevent delamination of the components of the first strap  108 , and/or seal the magnetic insert  202  so that the magnetic particles (which may be partially exposed along the sidewalls of the holes  210 ) do not contact or damage other components of the band  104 . 
     While  FIG. 2  illustrates an assembly that includes three components, this is merely exemplary, and the first strap  108  may include or be formed from more or fewer components. Moreover, the first strap  108  and the magnetic insert  202  may not be assembled as shown or implied in  FIG. 2 . For example, the first strap  108  may be a single, monolithic polymer structure having magnetic particles suspended throughout the first strap  108 . As another example, the first strap  108  may be a single, monolithic polymer structure having magnetic particles suspended only in (or concentrated most heavily in) certain positions, such as the areas proximate the holes  210 . As yet another example, the magnetic insert  202  may have a core of reinforcing material, and a polymer having magnetic particles suspended therein may encapsulate the core. The polymer material with the magnetic particles may be sprayed, overmolded, dip-coated, or otherwise applied to the core in order to form the magnetic insert  202 . 
     As noted above, bands for watches and other wearable devices may have clasps that allow the user to open and close the band to facilitate application and removal of the device from the user&#39;s wrist.  FIG. 3  illustrates a partial view of the band  104 , showing the first and second straps  108 ,  106  in an uncoupled configuration with the clasp  110  in an open configuration.  FIG. 4  illustrates a partial view of the band  104  showing the first and second straps  108 ,  106  coupled together via the clasp  110 , which is in a closed configuration. 
     The clasp  110  includes a strap connection portion  306  that is pivotally coupled to the second strap  106 . The strap connection portion  306  is also coupled to a pair of spring arms  310 . The spring arms  310  include and/or are otherwise connected to buttons  308  that are accessible from the sides of the strap connection portion  306  and which facilitate unlatching of the clasp  110  to open the clasp  110  from a closed configuration ( FIG. 4 ). The spring arms  310  are pivotally coupled to a base portion  304  of the clasp  110 . 
     The base portion  304  includes a magnetic protrusion  302  extending from a surface  314  of the base portion  304 . The magnetic protrusion  302  may be a permanent magnet of any appropriate material, such as neodymium iron boron, samarium cobalt, alnico, ceramic, or the like. The magnetic protrusion  302  is configured to be disposed in one of the holes  112  and to magnetically couple to the magnetic insert  202  of the first strap  108 . As shown, the clasp  110  includes one magnetic protrusion  302 , but more may be used (e.g., two, three, four, or more magnetic protrusions may be disposed on the clasp  110 , set apart from one another by the same distance as the holes  112 ). Moreover, the base portion  304  of the clasp  110  may also be magnetic. 
     In embodiments where the holes  112  are through-holes extending through the whole thickness of the first strap  108 , the clasp  110  may include a second magnetic protrusion (not shown) extending away from the strap connection portion  306  and configured to be disposed in the same hole  112  as the magnetic protrusion  302 . The second magnetic protrusion may magnetically and mechanically couple to the magnetic insert  202  in the same or similar manner as the magnetic protrusion  302 , and may also magnetically couple to the magnetic protrusion  302 . 
     The holes  112  and the magnetic protrusion  302  may also include undercuts, recesses, angled surfaces, or other features that are configured to mechanically engage with one another to prevent the first and second straps  108 ,  106  from separating from one another. For example, the holes  112  may include undercuts near the interior ends of the holes, and the magnetic protrusion  302  may have a feature that is configured to be disposed in the undercuts. When the magnetic protrusion  302  is disposed in a given hole  112 , the feature may be disposed in and engaged with the undercut. Moreover, the undercut and the feature may be configured so that a separation or expansion force on the band (e.g., as may be caused during normal use of the band) tends to further force the feature to engage with the undercut, thereby increasing the strength and security of the mechanical engagement between the magnetic protrusion  302  and the first strap  108 . 
     The spring arms  310  of the clasp  110  are configured to couple to arms  312  of the base portion  304  to retain the clasp  110  in a closed configuration (shown in  FIG. 4 ). In particular, the spring arms  310  and the arms  312  may include latching features  315  that engage with one another to retain the spring arms  310  to the arms  312 . The latching features  315  may be configured such that pressing on the buttons  308  when the clasp  110  is in the closed configuration causes the latching features  315  to disengage sufficiently that a wearer can pivot the spring arms  310  out of engagement with the arms  312  and thus open the clasp  110 . 
       FIG. 5  is a partial cross-sectional view of the band  104 , taken through line  5 - 5  in  FIG. 4 . As shown in  FIG. 5 , the magnetic protrusion  302 , which is coupled to the base portion  304  of the clasp  110 , is disposed in a hole  112 - 1 . The magnetic protrusion  302  extends through the second layer  204  and into the magnetic insert  202 , thereby mechanically retaining the second strap  106  to the first strap  108 . In particular, the mechanical engagement between the magnetic protrusion  302  and the first strap  108  prevents the first and second straps  108 ,  106  from sliding with respect to one another, and thus ensures that the band  104  remains at the size selected by a wearer. Moreover, as discussed herein, the placement of the magnetic protrusion  302  within the hole  112 - 1  of the magnetic insert  202  also results in a magnetic attraction between the magnetic protrusion  302  and the magnetic insert  202  that helps retain the first and second straps  108 ,  106  together, and also provides a positive tactile feedback to a user indicating that the magnetic protrusion  302  has positively engaged the first strap  108 . 
     In addition to the magnetic attraction between the magnetic protrusion  302  and the magnetic insert  202 , when the clasp  110  is in the closed configuration, the first strap  108  is captured between the surface  314  and the strap connection portion  306  such that the magnetic protrusion  302  is retained in the hole  112 - 1 . In particular, when the clasp  110  is in the closed configuration, the space between the strap connection portion  306  and the surface  314  is such that the first strap  108  cannot be lifted off from the magnetic protrusion  302 . For example, the distance between the strap connection portion  306  and the surface  314  may be approximately the same as the thickness of the first strap  108  in the area where the first strap  108  is designed to be inserted into the clasp  110 . In some cases, the distance between the strap connection portion  306  and the surface  314  may be less than the thickness of the first strap  108 . In such cases, the first strap  108  may be slightly compressed between the strap connection portion  306  and the surface  314 , thereby securely coupling the first and second strap  108 ,  106  as well as reducing or eliminating gaps and clearances that might result in play or an otherwise loose coupling. 
       FIG. 6  is a detail view of the area  500  in  FIG. 5 , showing the magnetic protrusion  302  disposed in the hole  112 - 1 . The arrows  600 ,  602 , and  604  illustrate the magnetic pole orientations of the magnetic insert  202  and the magnetic protrusion  302 . In particular, as noted above, the magnetic pole orientation of the magnetic insert  202 , shown by arrows  600  and  602 , is substantially parallel with the longitudinal axis  212  ( FIG. 2 ) of the first strap  108 . Similarly, the magnetic pole orientation of the magnetic protrusion  302  (when the protrusion is disposed in the hole  112 - 1 ) is substantially parallel with the longitudinal axis  212  of the first strap  108 , and faces the same direction as the magnetic pole orientation of the magnetic insert  202 . (The arrows  600 ,  602 , and  604  may also correspond to a magnetic flux field line of the magnetic fields produced by the magnetic insert  202  and the magnetic protrusion  302 .) 
     When the magnetic protrusion  302  is brought into proximity of the hole  112 - 1 , the magnetic protrusion  302  is subject to an attraction that tends to bring the magnetic field of the magnetic insert  202  into alignment with (e.g., in line with) the magnetic field of the magnetic protrusion  302 . The tendency of these magnetic fields to align with one another results in a force that tends to draw the magnetic protrusion  302  into the hole  112 - 1  of the magnetic insert  202 . Thus, while the direction of the magnetic flux through the magnetic insert  202  and the magnetic protrusion  302  is substantially parallel to the longitudinal axis  212  of the first strap  108 , a resulting attraction force is perpendicular to the longitudinal axis  212  (as shown by arrow  700  in  FIG. 7 ). 
       FIG. 7  is another detail view of the area  500  in  FIG. 5 , illustrating forces that may be present in the band  104  during use. For example, arrows  702  and  704  illustrate the forces that may be applied to the second strap  106  and the first strap  108 , respectively, when the band  104  is being worn (e.g., a separation or expansion force). As a result of the separation forces, a side of the magnetic protrusion  302  engages with a side of the hole  112 - 1  (e.g., at interface  706 ). This mechanical engagement prevents the first and second straps  108 ,  106  from separating and allowing the band  104  to open or loosen. Arrow  700 , on the other hand, represents the force produced by the interaction between the magnetic fields of the magnetic insert  202  and the magnetic protrusion  302  that tends to draw (and retain) the magnetic protrusion  302  in the hole  112 - 1  (also referred to as an attraction axis). 
       FIG. 8  is an exploded view of a first strap  800 . The first strap  800  is similar to the first strap  108 , but instead of (or in addition to) a flexible magnetic insert, the first strap  800  defines an array of holes  802  each having a ferromagnetic insert  804  disposed therein. 
     The first strap  800  may be formed from or include any appropriate material(s), such as leather, fabric, polymers, and so forth. The first strap  800  may comprise a monolithic component, such as a molded polymer material, or it may comprise multiple components, such as multiple layers of material that are stitched, adhered, bonded, or otherwise coupled together. 
     The ferromagnetic inserts  804  may be magnets formed from or including any appropriate material, such as iron, nickel, cobalt, and/or alloys thereof. The ferromagnetic inserts  804  may be coupled to the first strap  800  within the holes  802  (e.g., on the bottom surface of the blind holes) by any appropriate mechanism. For example, the ferromagnetic inserts  804  may be glued or otherwise bonded to the first strap  800 , and/or coupled via mechanical means (e.g., the first strap  800  may define or include undercuts or other retention features in the holes  802  that mechanically engage with the ferromagnetic inserts  804 ). The ferromagnetic inserts  804  are configured to magnetically couple to a magnetic engagement feature  908  of a clasp  906  ( FIG. 9 ). 
     The ferromagnetic inserts  804  may have any suitable shape and size. For example, the ferromagnetic inserts  804  may be disk- or plate-shaped pieces of ferromagnetic material. More particularly, the ferromagnetic inserts  804  may be substantially flat (with or without contoured surfaces, as described herein), and may be circular, oblong, square, octagonal, or any other suitable shape. 
     The holes  802  may be blind holes, and the ferromagnetic inserts  804  may be coupled to the blind end (e.g., the bottom) of the blind holes  802 . In embodiments where the holes  802  are blind holes, a surface of the first strap  800  may be substantially continuous or unbroken. By contrast, through holes would leave an opening in a surface of the first strap  800 , which may reduce the security and durability of the strap. For example, openings on an exterior surface of the first strap  800  may catch and/or retain foreign objects or particles, which could lead to unintended opening or detachment of a band. Moreover, the ferromagnetic inserts  804  may be supported by or on the bottom surface of the blind holes. This also positions the ferromagnetic inserts  804  above a magnetic engagement feature of a clasp (e.g., the magnetic engagement feature  904 ,  FIG. 9 ), thus orienting the ferromagnetic inserts  804  to magnetically couple to the magnetic engagement feature (as described herein). 
       FIG. 9  is a partial view of a band  900 , showing the first strap  800  and a second strap  910  coupled to a strap connection portion  914 . The second strap  910  may be made of the same or similar materials as the first strap  800 , and is coupled to a clasp  906 .  FIG. 9  shows the first and second straps  800 ,  910  in an uncoupled configuration with the clasp  906  in an open configuration. 
     The clasp  906  is substantially similar to the clasp  110 , but instead of the magnetic protrusion  302 , the clasp  906  includes a magnetic engagement feature  908  extending from a surface  916  of the clasp  906 . The magnetic engagement feature  908  is configured to be disposed in a respective one of the holes  802  and to magnetically couple to the ferromagnetic insert  804  disposed in the respective hole  802 . As shown, the clasp  906  includes one magnetic engagement feature  908 , but more may be used. The magnetic engagement feature  908  is also configured to mechanically retain the second strap  910  to the first strap  800  in a manner similar to that described herein with respect to the magnetic protrusion  302 . 
       FIG. 10  is a partial cross-sectional view of the band  900 , taken through a line corresponding to line  5 - 5  in  FIG. 4 . (While  FIG. 4  depicts a different embodiment than  FIG. 10 , the line  5 - 5  in  FIG. 4  is merely used to indicate the location of the cross-sectional view of the band  900  that is shown in  FIG. 10 .) As shown in  FIG. 10 , the magnetic engagement feature  908 , which is coupled to a base portion  1002  of the clasp  906 , is disposed in a hole  802 - 1 . The magnetic engagement feature  908  extends into the hole  802 - 1 , thereby mechanically retaining the first strap  800  to the second strap  910 . Moreover, the magnetic engagement feature  908  is magnetically attracted to a ferromagnetic insert  804 - 1  disposed in the hole  802 - 1 , which retains the first and second straps  800 ,  910  together and also provides a positive tactile feedback to a user indicating that the magnetic engagement feature  908  has positively engaged the first strap  800 . Apart from the differences between the magnetic engagement feature  908  and the magnetic protrusion  302 , the clasp  906  operates similar to the clasp  110  (described with respect to  FIGS. 3-5 ). For example, the clasp  906  captures (and may compress) the first strap  800  between a surface  1004  of the base portion  1002  and the strap connection portion  914  such that the magnetic engagement feature  908  is retained in the hole  802 - 1 . 
     The magnetic engagement feature  908  comprises a magnet  1010  and an encasing structure  1012 . The magnet  1010  may be formed from or include any appropriate material, such as neodymium iron boron, samarium cobalt, alnico, ceramic, or the like. The magnet  1010  may be a single magnet, or may include multiple magnets. The encasing structure  1012  surrounds at least part of the magnet  1010 . In the embodiment shown in  FIGS. 9-11 , the magnet  1010  is a cylinder, and the encasing structure  1012  surrounds the magnet  1010  around the circumference of the cylinder and along the bottom of the magnet  1010 . The encasing structure  1012  may be open along a top portion, thus exposing the magnet  1010  to the ferromagnetic insert  804 - 1 . The encasing structure  1012  may be formed from any appropriate material, such as a magnetic stainless steel (e.g., martensitic and/or ferritic stainless steel), a non-magnetic stainless steel (e.g., austenitic stainless steel), or the like. 
     The encasing structure  1012  may be configured to direct or concentrate the magnetic field produced by the magnet  1010 . For example, by surrounding the magnet  1010  with a non-magnetic stainless steel, the magnetic field produced by the magnet  1010  may be concentrated nearer to the magnet  1010  than would be the case if no encasing structure  1012  were used (or, for example, if a plastic or other non-metal material were used for the encasing structure  1012 ). Additionally, the encasing structure  1012  may be configured and/or shaped to prevent the magnet  1010  from contacting the ferromagnetic insert  804  when the magnetic engagement feature  908  is disposed in the hole  802 . For example, as shown and described with respect to  FIGS. 12A-12I , the magnet  1010  may be recessed from a top of the encasing structure  1012 , and the ferromagnetic insert  804  may have a size and/or shape that engages the top portion of the encasing structure  1012  such that direct contact between the magnet  1010  and the ferromagnetic insert  804  is prevented. This configuration may help prevent the magnet  1010  from being damaged by impacts with the ferromagnetic insert  804 . In particular, the magnetic attraction between the magnet  1010  and the ferromagnetic insert  804  may be sufficiently high that if they were allowed to couple directly to one another, the force of the impact could crack or break either or both of the components. Thus, the encasing structure  1012  separates the magnet  1010  from the ferromagnetic insert  804  via an air gap or an interstitial material/component. 
       FIG. 11  is a detail view of the area  1008  in  FIG. 10 , showing the magnetic engagement feature  908  disposed in the hole  802 - 1 . The magnetic pole orientation of the magnet  1010  (when the magnetic engagement feature  908  is disposed in the hole  802 - 1 ) is substantially perpendicular to a longitudinal axis  806  ( FIG. 8 ) of the first strap  800  and substantially perpendicular to a plane defined by a coupling face of the ferromagnetic insert  804 - 1 , as represented by arrow  1102 . The arrow  1102  may also correspond to a magnetic flux field line of the magnetic field produced by the magnet  1010 . 
     When the magnetic engagement feature  908  is brought into proximity of the hole  802 - 1 , the magnetic engagement feature  908  is subject to a magnetic attraction that tends to draw the magnetic engagement feature  908  into the hole  802 - 1  of first strap  800 . Unlike the magnetic circuit described with respect to  FIG. 6  where the magnetic flux through the magnetic insert  202  and the magnetic protrusion  302  is substantially parallel with the longitudinal axis  212  of the first strap  108 , the magnetic flux through the magnetic circuit formed by the ferromagnetic insert  804 - 1  and the magnetic engagement feature  908  is substantially perpendicular to the longitudinal axis  806  of the first strap  800 . Stated another way, the ferromagnetic insert  804 - 1  is attracted to the magnetic engagement feature  908  along a direction substantially parallel to or in line with an insertion direction of the magnetic engagement feature  908 . 
       FIGS. 12A-12I  illustrate cross-sections of various embodiments of the magnetic engagement feature  908  and the ferromagnetic insert or plate  804 - 1  (which together may be referred to as a magnetic coupling mechanism), taken through line  12 - 12  in  FIG. 9 . As noted above, maintaining a physical separation between the magnet  1010  and the ferromagnetic insert  804 - 1  may prevent the magnet  1010  from being damaged by impacts with the ferromagnetic insert  804 - 1 . Accordingly, each of the embodiments shown in  FIGS. 12A-12I  includes either air gaps or an interstitial material between the magnet and the ferromagnetic insert. Moreover, each embodiment shown in  FIGS. 12A-12I  includes a ferromagnetic insert or plate, a magnet, and an encasing structure, which are similar in function to the ferromagnetic insert/plate  804 - 1 , magnet  1010 , and encasing structure  1012 , respectively, described with respect to  FIGS. 8-11 . Structural differences between these components are discussed herein and/or shown in the figures. 
       FIG. 12A  illustrates the magnetic coupling mechanism shown in  FIGS. 9-11 . The magnet  1010  is disposed within the encasing structure  1012 , and a top portion of the encasing structure  1012  engages with the ferromagnetic insert  804 - 1  such that an air gap  1201  remains between the magnet  1010  and the ferromagnetic insert  804 - 1  when the magnet  1010  and the ferromagnetic insert  804 - 1  are magnetically coupled. In particular, the rim around the opening of the encasing structure  1012  is angled (e.g., forming a convex surface) to correspond to the angled outer edge of the ferromagnetic insert  804 - 1 . When the ferromagnetic insert  804 - 1  is in contact with the rim of the encasing structure  1012 , the ferromagnetic insert  804 - 1  is set apart from the magnet  1010  by a gap. The encasing structure  1012  may be formed from or include a magnetic stainless steel, or any other appropriate material. An arrow  1200  illustrates the magnetic pole orientation of the magnet  1010  (e.g., the north and south poles of the magnet  1010  may be oriented along a vertical line with respect to the orientation shown in  FIG. 12A ). 
       FIG. 12B  illustrates an embodiment of a magnetic coupling mechanism that includes a ferromagnetic plate  1202 , a magnet  1208  (with an arrow  1210  indicating the magnetic pole orientation of the magnet  1208 ), and an encasing structure that includes a base structure  1206  and a cap  1204  over a top portion of the base structure  1206  (and defining at least part of a top surface of the encasing structure). The base structure  1206  is formed from or includes a magnetic stainless steel (or any other appropriate material), and the cap  1204  is formed from or includes a non-magnetic stainless steel. The selection of the materials for the base structure  1206  and the cap  1204  (and indeed any of the components of the encasing structure in this or any other embodiments) may be based at least in part on a desired shape and/or concentration of the magnetic field produced by the magnet  1208  together with the encasing structure. 
     The base structure  1206  has a convex surface that engages (e.g., conforms to) a concave surface of the ferromagnetic plate  1202 . Thus, the ferromagnetic plate  1202  forms a continuous contact surface with a top portion of the encasing structure (e.g., the cap  1204  and the edges of the base structure  1206 ). However, the magnet  1208  is separated from the cap  1204  by an air gap  1203 . The presence (and/or the size) of the air gap  1203  may be determined based on a desired strength of the magnetic attraction between the magnet  1208  and the ferromagnetic plate  1202 . 
       FIG. 12C  illustrates an embodiment of a magnetic coupling mechanism that includes a ferromagnetic plate  1212 , a magnet  1218  (with an arrow  1220  indicating the magnetic pole orientation of the magnet  1218 ), and an encasing structure that includes a base structure  1216  and a cap  1214  over a top of the base structure  1216  (and defining a top of the encasing structure). The base structure  1216  is formed from or includes a magnetic stainless steel (or any other appropriate material), and the cap  1214  is formed from or includes a non-magnetic stainless steel. The selection of the materials for the base structure  1216  and the cap  1214  may be based at least in part on a desired shape and/or concentration of the magnetic field produced by the magnet  1218  together with the encasing structure. 
     The cap  1214  has a convex surface that engages (e.g., conforms to) a concave surface of the ferromagnetic plate  1212 . Thus, the ferromagnetic plate  1212  forms a continuous contact surface with a top portion or surface of the cap  1214 . However, the magnet  1218  is separated from the cap  1214  by an air gap  1215 . The presence (and/or the size) of the air gap  1215  may be determined based on a desired strength of the magnetic attraction between the magnet  1218  and the ferromagnetic plate  1212 . 
       FIG. 12D  illustrates an embodiment of a magnetic coupling mechanism that includes a ferromagnetic plate  1222 , a first magnet  1228 , a second magnet  1230 , and an encasing structure that includes a base structure  1226  and a cap  1224  over a top of the base structure  1226  (and defining a top of the encasing structure). The base structure  1226  is formed from or includes a magnetic stainless steel (or any other appropriate material), and the cap  1224  is formed from or includes a non-magnetic stainless steel. The selection of the materials for the base structure  1226  and the cap  1224  may be based at least in part on a desired shape and/or concentration of the magnetic field produced by the magnets  1228 ,  1230  together with the encasing structure. While the cap  1224  has curved outer edges, the ferromagnetic plate  1222  has a substantially rectangular cross-section, and a substantially planar portion of the ferromagnetic plate  1222  contacts a substantially planar top portion of the cap  1224 . 
     The first magnet  1228  and the second magnet  1230  have magnetic pole orientations that are parallel to one another but face in opposite directions, as illustrated by arrows  1234 ,  1232 , respectively. By using two magnets with the illustrated magnetic pole orientations, the magnetic fields produced by the first and second magnets  1228 ,  1230  can be directed or concentrated as desired. For example, the magnetic field produced by the first magnet  1228  may be drawn towards the second magnet  1230 , and vice versa, producing a more concentrated magnetic field in the vicinity of the first and second magnets than would be achieved with a single magnet of the same material. 
       FIG. 12E  illustrates an embodiment of a magnetic coupling mechanism that includes a ferromagnetic plate  1236 , a magnet  1242  (with an arrow  1248  indicating the magnetic pole orientation of the magnet  1242 ), and an encasing structure that includes a base structure  1246 , a sidewall structure  1240 , and a cap  1238  over a top of the base structure  1246  (and defining at least part of a top surface of the encasing structure). The base structure  1246  and the sidewall structure  1240  are formed from or include a magnetic stainless steel (or any other appropriate material), and the cap  1238  is formed from or includes a non-magnetic stainless steel. The selection of the materials for the base structure  1246 , the sidewall structure  1240 , and the cap  1238  may be based at least in part on a desired shape and/or concentration of the magnetic field produced by the magnet  1242  together with the encasing structure. 
     The sidewall structure  1240  and the cap  1238  together form a convex surface that engages (e.g., conforms to) a concave surface of the ferromagnetic plate  1236 . Thus, the ferromagnetic plate  1236  forms a continuous contact surface with the top surface of the cap  1238  and a portion of the sidewall structure  1240 . 
       FIG. 12F  illustrates an embodiment of a magnetic coupling mechanism that includes a ferromagnetic plate  1250 , a magnet  1256  (with an arrow  1260  indicating the magnetic pole orientation of the magnet  1256 ), and an encasing structure that includes a base structure  1258  and a cap  1254  over a top of the base structure  1258  (and defining a top surface of the encasing structure). The base structure  1258  is formed from or includes a magnetic stainless steel (or any other appropriate material), and the cap  1254  is formed from or includes a non-magnetic stainless steel. The cap  1254  has a convex surface that engages (e.g., conforms to) a concave surface of the ferromagnetic plate  1250 . Thus, the ferromagnetic plate  1250  forms a continuous contact surface with a top portion or surface of the cap  1254 . 
     The selection of the materials for the base structure  1258  and the cap  1254  may be based at least in part on a desired shape and/or concentration of the magnetic field produced by the magnet  1256  together with the encasing structure. For example, the embodiment of  FIG. 12F  has a similar geometry to the embodiment of  FIG. 12E , but a greater amount of the encasing structure in  FIG. 12F  is formed from non-magnetic stainless steel as compared to  FIG. 12E . This may produce a different shape and/or concentration of the magnetic field produced by the magnet  1256 , and thus produce a different magnetic attraction with the ferromagnetic plate  1250  than would be achieved with the embodiment of  FIG. 12E . 
       FIGS. 12G-12I  illustrate embodiments of a magnetic coupling mechanism that include a magnet  1266  (with an arrow  1270  indicating the magnetic pole orientation of the magnet  1266 ), and an encasing structure that includes a base structure  1268  and a cap  1264  over a top of the base structure  1268  (and defining a top surface of the encasing structure). The base structure  1268  is formed from or includes a magnetic stainless steel (or any other appropriate material), and the cap  1264  is formed from or includes a non-magnetic stainless steel. The cap  1264  has a convex surface, a top portion or surface of which engages (e.g., conforms to) a portion of a ferromagnetic plate. 
       FIGS. 12G-12I  each illustrate a cap having a different shape.  FIG. 12G  includes a ferromagnetic plate  1262  that has a concave surface that is configured to engage (e.g., conform to) a top portion or surface of the cap  1264 , and a convex surface opposite the concave surface.  FIG. 12H  includes a ferromagnetic plate  1272  that has a substantially planar surface that is configured to engage with a top portion or surface of the cap  1264 , and a convex surface opposite the concave surface.  FIG. 12I  includes a ferromagnetic plate  1274  that has a substantially rectangular cross-section, thus defining substantially planar surfaces on both a top and bottom of the ferromagnetic plate  1274  (with respect to the orientation shown in  FIG. 12I ). The shapes of the ferromagnetic plates in  FIGS. 12G-12I  (and indeed any of the ferromagnetic inserts described herein) may be selected based on any appropriate criteria, such as the strength of the magnetic attraction to a magnetic coupling mechanism, mechanical engagement with a magnetic coupling mechanism and/or a strap, or the like. 
       FIG. 13  illustrates a process  1300  of manufacturing a magnetic strap for a wearable device. The process  1300  may be used to manufacture a strap such as the first strap  108  of the band  104 , described above, though the process  1300  may be used to form other straps as well. As shown and described, the process  1300  includes several steps. It will be understood that the process  1300  may include more or fewer steps than those described, and the steps may be reordered, combined, and/or omitted. Moreover, the process  1300  is not an exhaustive list of all possible techniques or methods that may be used to manufacture the straps that are described herein. On the contrary, the straps (e.g., the first strap  108 ) may be manufactured or produced in any appropriate way. 
     At operation  1302 , a magnetizable material is mixed with a polymer material to form a moldable mixture that is used to form a magnetizable insert (e.g., a precursor to the magnetic insert  202 ,  FIG. 2 ). The magnetizable material (e.g., particles of neodymium iron boron, samarium cobalt, alnico, ceramic, or the like) may be mixed with any appropriate polymer material (e.g., nylon, polyurethane, silicone, or the like) in any appropriate way. For example, the magnetizable material may be mixed with a solid polymer feedstock prior to melting and/or molding of the polymer material. As another example, the magnetizable material may be added to a liquid (e.g., molten or uncured) polymer material. 
     At operation  1304 , a magnetizable insert in which the magnetizable material is suspended in the polymer material is formed. The magnetizable insert may be formed, for example, by introducing the moldable mixture into a mold cavity, and then allowing the moldable mixture to cure (e.g., to cool and/or chemically cure). The magnetizable material may be uniformly distributed throughout the polymer material, or it may be concentrated in certain areas. For example, the magnetizable material may be more densely distributed near the holes  210  in the flexible magnetic insert  202  in  FIG. 2 , and less densely distributed in areas away from the holes  210 . Thus, the strength, location, and/or shape of the magnetic field(s) produced by the magnetizable material may be tailored to achieve desired results. 
     After the magnetizable insert is molded, an encapsulating material may be applied to the magnetizable insert. The encapsulating material may be any appropriate material (e.g., silicone, polyurethane, nylon, paint, epoxy, or the like), and may be applied to the material in any appropriate way. For example, the encapsulating material may be sprayed, brushed, dip-coated, or overmolded onto the magnetizable insert. The encapsulating material may be applied to the entire insert, or it may be applied to selective portions of the insert (e.g., sidewalls and/or edges of holes formed in the insert). 
     Holes (e.g., holes  210 ,  FIG. 2 ) may be formed in the magnetizable insert during or after molding. For example, the mold cavity used to mold the insert may include features that form the holes in the insert during molding, such that the holes are included in the as-molded part. As another example, holes may be formed in the insert after it is molded, for example by drilling, punching, or cutting (e.g., with a laser, water jet, blade, or the like). Where the holes are formed after the insert is molded, an encapsulating or sealing material may be applied to the insert after the holes are formed. In particular, the process of forming the holes in the insert may expose portions of the magnetizable material, resulting in abrasive surfaces and/or edges, and the encapsulating or sealing material may cover such surfaces to prevent abrasion and/or damage to other components. 
     The magnetizable insert may then be magnetized, for example, by exposing the magnetizable insert to a magnetic field (e.g., with an electromagnet). The magnetizable insert may be magnetized such that a magnetic pole orientation of the magnetizable insert is substantially parallel to a longitudinal axis of a strap in which the magnetizable insert is to be incorporated. For example, a line extending from a north pole to a south pole of the magnetizable insert is substantially parallel with a longitudinal axis of a strap (e.g., the longitudinal axis  212 ). The magnetizable insert may be magnetized before the magnetizable insert is incorporated into a strap (e.g., before operations  1306 ,  1308 , below), or after it is incorporated into a strap (e.g., after operations  1306 ,  1308 ). 
     At operation  1306 , the magnetizable insert is disposed between a first layer and a second layer. The first and second layers may be formed from or include any appropriate material, such as leather, fabric, polymer (e.g., Vectran, Kevlar, silicone, nylon, or polyurethane). One or both of the first and second layers may include a recess or opening into which the magnetizable insert may be completely or partially disposed. For example, as shown in  FIG. 2 , a magnetizable insert (e.g., the magnetic insert  202 ) may be disposed in a recess (e.g., the recess  206 ) of a layer of material. 
     At operation  1308 , the first layer is coupled to the second layer such that the magnetizable insert is retained between the first layer and the second layer. The first layer may be coupled to the second layer in any appropriate manner, such as stitching, gluing, overmolding, spraying, welding (e.g., ultrasonic welding), or the like. 
     Holes may be formed in the second layer, which communicate with the holes in the magnetizable insert to form the holes into which a magnetic protrusion (or magnetic coupling mechanism) may extend. The holes in the second layer may be formed before the second layer is coupled to the first layer. For example, in some cases, the holes are formed in the second layer by drilling, punching, or cutting (e.g., with a laser, water jet, blade, or the like), and then the second layer is aligned with the magnetizable insert (which also has holes formed therein) so that the holes of the second layer and the magnetizable insert align. The aligned second layer and magnetizable layer are then coupled to the first layer to form the strap. The holes in the second strap and the magnetizable insert may be formed at the same time. For example, a magnetizable insert may be coupled to the second strap, and holes may be formed in both the second strap and the magnetizable insert by drilling, punching, or cutting (e.g., with a laser, water jet, blade, or the like). This ensures that the holes in the second strap and the holes in the magnetizable insert are properly aligned. The assembly including the second strap and the magnetizable insert may then be coupled to the first layer to form the strap. In some cases, holes are formed through the whole strap, including through the second layer, the magnetizable insert, and the first layer. In such cases, the holes may be formed (for example by drilling, punching, or cutting) after operation  1308 . 
     In some cases, instead of forming holes that extend through an entire thickness of the second layer, portions of the second layer are debossed (e.g., pressed) into the holes in the magnetizable layer that is disposed below the second layer. For example, the second layer may be coupled to the magnetizable layer, as part of or prior to operation  1308 , and a tool may be pressed onto the second layer over the holes in the magnetizable layer to force portions of the second layer into the holes. The tool may be heated to facilitate deformation of the material of the second layer. The material of the second layer may remain intact within the holes of the magnetic material, thus forming a cover over the surfaces defining the hole. This may help to cover abrasive portions of the magnetic insert and to prevent wear, damage, or delamination of the strap in the vicinity of the holes. Additionally, this may allow the strap to appear to be formed from a single material, even though it may be formed from multiple layers and components. 
     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 the specific embodiments described herein are presented for purposes of illustration and description. They are not targeted to be exhaustive or to limit the 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: 20160829
Publication Date: 20191105
Grant Date: 20191105
Priority Date: 20150930
Inventors: CHAMBERS, TREVOR S.
ZHU, HAO
Assignee: APPLE INC
CPC Classifications: [{"code": "A44C5/0061", "inventive": true, "first": false, "tree": "[]"}, {"code": "A44D2203/00", "inventive": false, "first": false, "tree": "[]"}, {"code": "G04B37/225", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01F7/0263", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F1/163", "inventive": true, "first": false, "tree": "[]"}, {"code": "A44C5/246", "inventive": true, "first": false, "tree": "[]"}, {"code": "H05K5/0217", "inventive": true, "first": false, "tree": "[]"}, {"code": "H05K5/0086", "inventive": true, "first": false, "tree": "[]"}, {"code": "A44C5/246", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F1/163", "inventive": true, "first": false, "tree": "[]"}, {"code": "A44C5/2071", "inventive": true, "first": true, "tree": "[]"}, {"code": "H01F7/021", "inventive": true, "first": false, "tree": "[]"}, {"code": "A44C5/2071", "inventive": true, "first": true, "tree": "[]"}, {"code": "G06F1/163", "inventive": true, "first": false, "tree": "[]"}, {"code": "A44C5/246", "inventive": true, "first": false, "tree": "[]"}, {"code": "H05K5/0217", "inventive": true, "first": false, "tree": "[]"}, {"code": "H05K5/0086", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01F7/021", "inventive": true, "first": false, "tree": "[]"}, {"code": "A44C5/2071", "inventive": true, "first": true, "tree": "[]"}]
Family ID: 68391718