Method and apparatus for producing magnetic attachment system

Abstract

A method and apparatus for producing a magnetic attachment mechanism is described. A method is provided for determining the magnetic field axis of an element prior to machining it. The magnetic field axis can be used as a reference to machine an outer surface of the magnetic element at a desired angle. The method provides a means to more precisely align magnetic field axes of corresponding magnets in a magnetic attachment system.

What is claimed is: 
     
         1 . A magnetic attachment system for use in a portable computing device, the portable computing device having a housing and a cover assembly, the magnetic attachment system comprising:
 a housing attachment feature embedded in the housing; and   a cover attachment feature embedded in the cover assembly, wherein
 the housing attachment feature and the cover attachment feature are adapted to establish a magnetic attractive force that places the cover assembly into a mating engagement with the housing at an engagement surface. 
   
     
     
         2 . The magnetic attachment system of  claim 1 , wherein:
 the housing attachment feature comprises a first magnetic material having a first magnetic field axis;   the cover attachment feature comprises a second magnetic material having a second magnetic field axis; and   the engagement surface is configured such that the first magnetic field axis and the second magnetic field axis are substantially aligned to one another.   
     
     
         3 . The magnetic attachment system of  claim 1 , wherein at least one of the first and second magnetic material comprises a rare earth element. 
     
     
         4 . The magnetic attachment system of  claim 1 , wherein the engagement surface comprises a first surface of the cover assembly conforming to a second surface of the housing. 
     
     
         5 . The magnetic attachment system of  claim 2 , wherein:
 the first magnetic material is formed into a shape conformal to a shape of the housing; and   the second magnetic material is formed into a shape conformal to the shape of the first magnetic material.   
     
     
         6 . The magnetic attachment system of  claim 1 , wherein the engagement surface is curved to provide a more secure attachment between the housing and the cover assembly. 
     
     
         7 . The magnetic attachment system of  claim 1 , wherein the engagement surface is configured to place the housing attachment feature in close proximity to the cover attachment feature thereby increasing the magnetic attractive force that places the cover assembly into a mating engagement with the housing. 
     
     
         8 . A portable computing device including a housing and a cover assembly adapted to form a mating engagement with the housing, the portable computing device comprising:
 a first magnetic material embedded in the housing, providing a first magnetic field;   a second magnetic material embedded in the cover assembly, providing a second magnetic field; and   an engagement surface formed between the housing and the cover assembly, the engagement surface configured to provide an attractive magnetic force between the housing and the cover assembly by aligning the first magnetic field with the second magnetic field, and placing the first magnetic material in close proximity from the second magnetic material.   
     
     
         9 . The portable computing device of  claim 8 , further comprising a cover glass and a flap; wherein each of a plurality of magnetic materials is embedded in the cover glass and the flap. 
     
     
         10 . The portable computing device of  claim 8 , wherein the first magnetic material and the second magnetic material comprise at least one of the group consisting of neodymium, iron, boron, and an alloy thereof. 
     
     
         11 . The portable computing device of  claim 8 , wherein the first magnetic material is formed into a shape that conforms with a surface of the housing adjacent to the engagement surface. 
     
     
         12 . The portable computing device of  claim 8 , wherein the second magnetic material is formed into a shape that conforms with a shape of the first magnetic material. 
     
     
         13 . The portable computing device of  claim 8 , wherein at least one of the first magnetic material and the second magnetic material is formed of a sintered block having an outer surface that is machined at a desired angle relative to an axis of the first magnetic field or the second magnetic field. 
     
     
         14 . A fixture for supporting a magnetic element and for determining a magnetic field axis of the magnetic element, the fixture being configured to:
 support a sintered element while allowing the sintered element to freely align with an external magnetic field applied to the sintered element;   fix the sintered element in a locked position in the fixture after the sintered element freely aligns with the external magnetic field; and   support the sintered element in the locked position while the sintered element is machined.   
     
     
         15 . The fixture of  claim 14 , wherein the fixture comprises:
 a first annular element configured to surround the sintered element and to provide a first axis of rotation for the sintered element;   a second annular element configured to surround the first annular element and to provide a second axis of rotation for the sintered element, the first and second annular elements each having a locking feature for preventing rotation about its respective axis; and   a base for supporting the sintered element and the first and second annular elements.   
     
     
         16 . The fixture of  claim 15 , wherein the base can be used to align the fixture to equipment for machining an outer surface of the sintered element, wherein the fixture can be aligned at a desired angle. 
     
     
         17 . The fixture of  claim 14 , wherein the fixture comprises:
 a liquid capable of suspending the sintered element therein, the liquid being capable of being frozen to fix and support the sintered element in the locked position.   
     
     
         18 . The fixture of  claim 14 , wherein the sintered element is allowed at least two degrees of freedom in the fixture. 
     
     
         19 . The fixture of  claim 14 , wherein the sintered element can rotate about a first axis and second axis, wherein the first axis is perpendicular to the second axis. 
     
     
         20 . The fixture of  claim 19 , wherein the magnetic field axis is perpendicular to both the first axis and the second axis.