Patent Publication Number: US-7900343-B1

Title: Magic spheres assembled from conically magnetized rings

Description:
GOVERNMENT INTEREST 
     The invention described herein may be manufactured, used, imported, sold, and licensed by or for the Government of the United States of America without the payment to me of any royalty thereon. 
    
    
     FIELD OF THE INVENTION 
     This present invention relates to magic sphere magnetic structures. More particularly, present invention relates to a magic sphere magnetic structure assembled from conically magnetized toroidal rings. 
     BACKGROUND OF THE INVENTION 
     One of the most useful permanent magnet structures is the hollow cylindrical flux source, or magic ring, which is a cylindrical permanent magnet shell that offers an interior magnetization vector that is more or less constant in magnitude throughout the interior cavity of the structure and produces a magnetic field greater than the remanence of the magnetic material from which it is made. The magic ring, also know as a magic cylinder or Halbach cylinder, produces comparatively high transverse fields in a cylindrical cavity which it encloses in the form of a cylindrical shell. They are well known and discussed in numerous publications and papers such as  Rare Earth Iron Permanent Magnets , edited by J M D Coey, Oxford Science Publications (1996) and U.S. Pat. Nos. 5,382,936 and 5,428,335, both entitled “Field Augmented Permanent Magnet Structures,” in which this inventor was a co-inventor.  FIG. 1  is a cross-sectional view of an abbreviated prior art magic ring magnetic structure, with 8 wedge-shaped pieces, the small arrows indicating magnetization direction of each wedge-shaped piece and the large central arrow indicating the magnetic field direction.  FIG. 1  also illustrates the angles θ and γ. The magic ring can be also approximated by assembling transversely magnetized rods that are circularly arranged about a central cylindrical space. 
     If a transverse section of a magic cylinder is rotated about its polar axis its locus forms a magic sphere.  FIG. 2  is a cross-sectional view of a prior art magic sphere magnetic structure with the small arrows indicating magnetization direction of each one of the numerous pieces assembled to form the prior art structure. 
     While the prior art magic ring and magic sphere structures each have a number of useful features and applications, they all suffer from one chronic disadvantage. The disadvantage with these magnetic structures is that they all require the painstaking assembly of numerous pieces with different magnetic orientations. For example, the magic sphere disclosed in Leupold U.S. Pat. No. 5,382,936 “Field Augmented Permanent Magnet Structures,” typically requires the assembly of at least 64 pieces with numerous magnetic orientations. Similarly, the magic ring typically requires assembly of as many as 26 different pieces with differing magnetic orientations. Such detailed fabrication and assembly requirements quickly lead to high manufacturing and assembly costs, as well as significant amounts of scrap material. For, these reasons, there has been a need to assemble magic ring or magic sphere magnetic structures in a way that requires fewer piece parts, less assembly time and decreased manufacturing costs. Up until now, this need has not been answered. 
     SUMMARY OF THE INVENTION 
     In order to answer the need for assembling magic ring and magic sphere magnetic structures with fewer piece parts, less assembly time and decreased manufacturing costs without suffering from the disadvantages, drawbacks and shortcomings of prior art magnetic structures, the present invention provides a relatively small number of magnetized toroidal rings with a conical magnetization direction that are stacked and assembled into a magic sphere magnetic structure. In prior art structures, these magic rings are composed of many small segments, but in this invention each magnetized toroidal ring is in one single, solid piece. Referring now to the drawings,  FIG. 3A  depicts a simplified top view of a prior art magic ring composed of many small pieces while,  FIG. 3B  depicts a simplified top view of a single, solid magnetized toroidal ring  10  in accordance with the present invention. 
     Accordingly, it is an object of the present invention to provide a simpler, less costly and easier to assemble magic sphere magnetic device. 
     It is another object of the present invention to provide a simpler, less costly and easier to assemble magic sphere magnetic device with a group of magnetized toroidal rings having different dimensions and a conical magnetic field direction. 
     It is still a further object of the present invention to provide a simpler, less costly and easier to assemble magic sphere magnetic device with magnetized toroidal rings with different dimensions and conical magnetic field direction by stacking the magnetized toroidal rings. 
     These and other objects and advantages are accomplished by this invention&#39;s magic sphere device assembled by stacking magnetized toroidal rings with different dimensions and a conical magnetic field direction into a magic sphere configuration. In accordance with the present invention, magnetic strands are magnetized toroidally then stacked coaxially, or coiled, in a beehive-like fashion to provide a magic sphere magnetic structure that can be assembled with far fewer piece parts than prior art magic spheres and provide this invention&#39;s magic sphere structure. This invention&#39;s objects and advantages are achieved by fabricating each of the magnetized toroidal rings with predetermined dimensions to form the inner and outer surfaces of a spherical shell. This invention&#39;s magic sphere device assembled from magnetized toroidal rings answers the need for assembling magic spheres in a simpler and less costly way with fewer piece parts, less assembly time and decreased manufacturing costs. The present invention also encompasses methods for assembling a magic sphere by stacking magnetized toroidal rings with a conical magnetic direction. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a cross-sectional view of a prior art magic cylinder magnetic structure; 
         FIG. 2  is a cross-sectional view of a prior art magic sphere magnetic structure; 
         FIG. 3A  depicts prior art magic sphere azimuthal segments; 
         FIG. 3B  depicts a magnetized toroidal ring in accordance with this invention; 
         FIG. 4  depicts one example of means for toroidal magnetization that may be used to form this invention&#39;s magnetized toroidal rings; 
         FIG. 5  is a perspective view of a single magnetized toroidal ring with a conical magnetic orientation following magnetization in a means for toroidal magnetization; and 
         FIG. 6  is a perspective view of a magic sphere formed by arranging a group of stacked magnetized toroidal rings around a polar axis in accordance with the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE DRAWINGS 
     This invention&#39;s magic sphere device is assembled from magnetic strands that have been magnetized in a means for toroidal magnetization into magnetized toroidal rings. In accordance with the present invention, the magnetized toroidal rings, each having a conical magnetization direction, are stacked in a beehive-like fashion to provide a magic sphere magnetic structure. By assembling this invention&#39;s magic sphere from stacked magnetized toroidal rings, the magic sphere magnetic structure can be assembled with far fewer piece parts than prior art magic spheres yet still provide all of the advantages of the magic sphere. 
     In accordance with the present invention, magnetic strands are converted into magnetized toroidal rings by a means for toroidal magnetization and then stacked to form a magic sphere structure. Referring now to the drawings,  FIG. 4  is one example of a toroidal magnetization means from this inventor&#39;s U.S. Pat. No. 4,911,627, entitled “Apparatus For Fabrication Of Permanent Magnet Toroidal Rings,” which is incorporated herein by reference. This example of the toroidal magnetization means comprises an upper segment  11  and a lower segment  12 . When the magnetic strand  10 , shown here in cross-section, is deposited into the toroidal magnetization means and bent into a toroid at an angle with respect to the vertical or horizontal planes, then the magnetization direction will be at an angle with respect to the toroidal axis and provide the  FIG. 3B  magnetized toroidal ring  10  with a selected, angled, or conical interior magnetic field. 
     Each of this invention&#39;s magnetized toroidal rings has a conical magnetization whose cone angle varies according to this formula:
 
(γ=2θ)
 
where θ is the polar angle of the magnetized toroidal ring&#39;s location in the magic sphere. This polar angle is illustrated in  FIG. 1 . This formula accounts for the greater strength achieved by each of this invention&#39;s toroidal rings following magnetization.  FIG. 5  depicts a single toroidal magnetic ring  10  with a spherical inner surface  13 , spherical outer surface  14 , and a conical magnetic orientation indicated by the broken lines  15  projecting downward.
 
       FIG. 6  is a perspective view of this invention&#39;s a magic sphere  30  formed by arranging a group of differently-dimensioned magnetized toroidal rings  10 A- 10 H stacked coaxially around a hollow central cavity  16  and a spherical polar axis  17 . The magnetized toroidal rings  10 A- 10 H are stacked coaxially around the polar axis  17  with each magnetized toroidal ring having a predetermined circumference and forming an inner shell surface  18  and an outer shell surface  19  of the shell  20  of the magic sphere  30 . This invention&#39;s easier-to-assemble magic sphere  30  provides a vertical magnetic field along the spherical polar axis  17 , which is represented by the arrow  21 . The magnetized toroidal rings  10 A- 10 H are positioned along parallels of latitude of the magic sphere  30 . By magnetizing the magnetic strands in a means for toroidal magnetization according to the (γ=2θ) formula, this invention&#39;s advantageous magic sphere structure is composed of a minimal number of unsegmented toroidal magnetic rings with conical, or angled, magnetic field orientation. The magic sphere device is completed with smaller top and bottom magic spheres,  22  and  23 , respectively, which bypass the toroidal magnetization means because they will retain their spherical shape and are positioned at the top and bottom of the stacked magnetized toroidal rings  10 A- 10 H. The spherical outer surface of the magnetized toroidal ring  10 A in  FIG. 6  is slightly exaggerated in that drawing to emphasize that each magnetized toroidal ring  10 A- 10 H needs to have that type of outer surface in order to form the spherical shell  20  when the rings  10 A- 10 H are stacked. 
     When each of the magnetized toroidal rings  10 A- 10 H and magic spheres  22  and  23  maintain their given internal horizontal or vertical magnetic orientations, and the magnetized toroidal rings  10 A- 10 H are shaped to have the appropriate spherical inner and outer surfaces  13  and  14 , rather than being of simple circular cross section, then the magic sphere can be made as exact, or ideal, as desired by using a sufficient number of magnetized toroidal rings so as to approach a continuous change in field direction with change in θ. 
     A number of variations are considered to be within the contemplation of this invention, such as assembling the magic sphere  30  with a sufficient number of unsegmented magnetic pieces so as to approach a continuous change in the vertical magnetic field direction with a change in the angle θ, and the sufficient number being at least eight or ten magnetic pieces. However, the number of magnetic pieces may be varied according to the designer&#39;s requirements. The present invention also encompasses a magic sphere magnetic device with unsegmented solid magnetized toroidal rings and many of the same variations apply to this embodiment. 
     The present invention also encompasses a method for assembling a magic sphere magnetic structure by stacking a group of magnetized toroidal rings, comprising the steps of forming a group of magnetic strands; dimensioning each of the group of magnetic strands with a different predetermined circumference; inserting the magnetic strands into a means for toroidal magnetization; forming a plurality of solid magnetized toroidal rings with each solid magnetized toroidal ring having a spherical inner surface, a spherical outer surface, and being magnetized with a different conical magnetization direction; coaxially aligning and stacking an upper magic sphere, the plurality of solid, magnetized toroidal rings, and a lower magic sphere around a spherical polar axis; and thereby providing a spherical shell. The method continues with the steps of forming the spherical shell with an inner shell surface, an outer shell surface, and a hollow central cavity; locating the spherical polar axis within the hollow central cavity; and generating a strong vertical magnetic field along the spherical polar axis with a minimal number of solid, magnetized toroidal rings in combination with the different conical magnetization directions. Many of the variations that are applicable to the other embodiments also apply to this invention&#39;s methods. 
     It is to be further understood that other features and modifications to the foregoing detailed description are within the contemplation of the present invention, which is not limited by this detailed description. Those skilled in the art will readily appreciate that any number of configurations of the present invention and numerous modifications and combinations of materials, components, arrangements and dimensions can achieve the results described herein, without departing from the spirit and scope of this invention. Accordingly, the present invention should not be limited by the foregoing description, but only by the appended claims.