Abstract:
The magnetic coupling system of the present invention overcomes drawbacks experienced by the prior art. A coupling system in accordance with one embodiment of the invention comprises a rotor assembly having a first mount portion connectable to a first shaft. A conductor assembly having a second mount portion is connectable to a second shaft. The second mount portion has first and second sections coupleable to each other and being independently positionable adjacent to the magnet holder. A first electro-conductive member is attached to the first section and positioned adjacent to the magnet holder. A second electro-conductive member is attached to the second section and positioned adjacent to the magnet holder. The first and second electro-conductive members are positioned adjacent to each other and spaced apart from the magnet holder by a gap.

Description:
CROSS-REFERENCE TO RELATED APPLICATION  
       [0001]     The present non-provisional patent application claims the benefit of and priority to U.S. Provisional Patent Application No. 60/629,689 filed Nov. 19, 2004, which is incorporated herein by reference thereto. 
     
    
     TECHNICAL FIELD  
       [0002]     The current invention is directed to coupling systems, and more particularly toward magnetic coupling systems.  
       BACKGROUND  
       [0003]     When a magnetic disk containing permanent magnets arranged so that opposing magnets on the disk are of opposite polarity is rotated between two non-ferrous electro-conductive disks, eddy currents are generated in the rotating disk resulting in magnetic friction between the electro-conductive disk and the magnetic disk. This magnetic friction will urge the magnetic disks to rotate. Accordingly, the electro-conductive disks and the magnetic disks can be used to couple two shafts together in order to transfer rotational motion between the shafts. The electro-conductive disks and magnetic disks can be used in a magnetic break, a magnetic brake, or other coupling devices.  
       SUMMARY  
       [0004]     The magnetic coupling system of the present invention overcomes drawbacks experienced by the prior art. A coupling system in accordance with one embodiment of the invention comprises a rotor assembly having a first mount portion connectable to a first shaft. A conductor assembly having a second mount portion is connectable to a second shaft. The second mount portion has first and second sections coupleable to each other and being independently positionable adjacent to the magnet holder. A first electro-conductive member is attached to the first section and positioned adjacent to the magnet holder. A second electro-conductive member is attached to the second section and positioned adjacent to the magnet holder. The first and second electro-conductive members are positioned adjacent to each other and spaced apart from the magnet holder by a gap. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0005]      FIG. 1  is a partially schematic cross-sectional elevation of a magnetic coupling system in accordance with embodiments of the invention.  
         [0006]      FIG. 2  is an isometric illustration of a portion of the magnetic coupling system shown in  FIG. 1  where a second shaft mount has been removed.  
         [0007]      FIG. 3A  is a partially schematic front elevation of the magnetic coupling system shown in  FIG. 1 .  
         [0008]      FIG. 3B  is a partially schematic cross-sectional elevation of the magnetic coupling system shown in  FIG. 3A  taken along line A-A.  
         [0009]      FIG. 4A  is an isometric illustration of a first shaft mount of the magnetic coupling system shown in  FIG. 1 .  
         [0010]      FIG. 4B  is a partially schematic front elevation of the first shaft mount shown in  FIG. 4A .  
         [0011]      FIG. 4C  is a partially schematic cross-sectional elevation of the first shaft mount shown in  FIG. 4B  taken along line A-A.  
         [0012]      FIG. 5A  is an isometric illustration of a magnet holder and magnets of the magnetic coupling system shown in  FIG. 1 .  
         [0013]      FIG. 5B  is a partially schematic front elevation of the magnet holder and magnets shown in  FIG. 5A .  
         [0014]      FIG. 5C  is a partially schematic back elevation of the magnet holder shown in  FIG. 5A  with the magnets removed.  
         [0015]      FIG. 5D  is a partially schematic cross-sectional elevation of the magnet holder and magnets shown in  FIG. 5C  taken along line A-A.  
         [0016]      FIG. 6A  is a partially schematic front elevation of an electro-conductive material section of the magnetic coupling system shown in  FIG. 1 .  
         [0017]      FIG. 6B  is a partially schematic side elevation of the electro-conductive material section shown in  FIG. 6A .  
         [0018]      FIG. 7A  is an isometric illustration of a second shaft mount of the magnetic coupling system shown in  FIG. 1 .  
         [0019]      FIG. 7B  is a partially schematic top plan view of the second shaft mount shown in  FIG. 7A .  
         [0020]      FIG. 7C  is a partially schematic front elevation of the second shaft mount shown in  FIG. 7A .  
         [0021]      FIG. 7D  is a partially schematic cross-sectional elevation of the second shaft mount shown in  FIG. 7C  taken along line A-A.  
         [0022]      FIG. 7E  is a partially schematic side elevation of the second shaft mount shown in  FIG. 7A .  
         [0023]      FIG. 7F  is a partially schematic cross-sectional elevation of the second shaft mount shown in  FIG. 7E  taken along line B-B.  
         [0024]      FIG. 7G  is a partially schematic cross-sectional elevation of the second shaft mount shown in  FIG. 7E  taken along line C-C. 
     
    
     DETAILED DESCRIPTION  
       [0025]     The present disclosure describes magnetic coupling devices and associated methods. Several specific details of the invention are set forth in the following description and in  FIGS. 1-7G  to provide a thorough understanding of certain embodiments of the invention. One skilled in the art, however, will understand that the present invention may have additional embodiments, and that other embodiments of the invention may be practiced without several of the specific features described below. For example, while selected dimensions may be provided on various Figures, these dimensions are for illustrative purposes only. In other embodiments, the magnetic coupling device and associated components can have significantly different dimensions than are shown in the illustrated embodiment.  
         [0026]     The magnetic coupling system  100 , shown in  FIGS. 1-7G , can include a magnet rotor assembly  110  and a conductor assembly  120 . The magnet rotor assembly  110  can be coupled to a first shaft  111  (shown in  FIG. 2 ) and the conductor assembly  120  can be coupled to a second shaft  121  (shown in  FIG. 2 ). The magnet rotor assembly  110  and/or the conductor assembly  121  can be coupled to the respective shaft(s) using various methods, for example, by using fasteners, a friction/interference fit, set screws, and/or shaft keys (shown in  FIG. 2 ).  
         [0027]     When the magnet rotor assembly  110  and a conductor assembly  120  are coupled to the first and second shafts  111  and  121 , the magnetic coupling system  100  can be used to transfer rotational movement of one shaft to the other shaft (e.g., coupling the shafts). For example, a motor can apply a rotational force (e.g., torque) to the first shaft  111  and the magnetic coupling system  100  can transmit the rotational force to the second shaft  121 . In certain embodiments, the magnetic coupling system  100  can be used as a clutch-type system to allow engagement and disengagement (e.g., coupling and decoupling) of the first shaft  111  and the second shaft  121 . In other embodiments, the magnetic coupling system  100  can be used to buffer movement between the first shaft  111  and the second shaft  121  by allowing one shaft to smoothly transition to another rotational speed in response to a sudden change in the rotation of the other shaft.  
         [0028]     The magnetic rotor assembly  110  can include a first shaft mount  112 , one or more magnet holders  113 , and one or more magnets  114  in each holder. The magnet holder  113  can be made of various materials, for example, a plastic, a metal, or a ceramic. In certain embodiments, the first shaft mount  112  and the magnet holder  113  can be an integral unit. In the illustrated embodiment, the magnet holder  113  is coupled to the first shaft mount  112 , which in turn can be coupled to the first shaft  111  (shown in  FIG. 2 ). Twelve magnets  114  are coupled to the magnet holder  113 . The twelve magnets are shown as a first magnet  114   a , a second magnet  114   b , a third magnet  114   c , a fourth magnet  114   d , a fifth magnet  114   e , a sixth magnet  114   f , a seventh magnet  114   g , an eighth magnet  114   h , a ninth magnet  114   i , a tenth magnet  114   j , an eleventh magnet  114   k , and a twelfth magnet  114   l . As shown in the illustrated embodiment, the magnets can be arranged symmetrically around the magnet holder  113  with adjacent magnets arranged so that they present opposite poles on each side of the magnet holder  113 . Other embodiments can have more or fewer magnets  114  and/or other arrangements and geometry (e.g., magnets can be stacked end-to-end, positive pole opposite negative pole, in openings around a magnet holder having a different size and shape than the magnet holder  113  shown in the illustrated embodiment).  
         [0029]     The conductor assembly can include a second shaft mount  122  and an electro-conductive material  123 . In the illustrated embodiment, the second shaft mount  122  includes two portions shown as a top portion  122   a  and a bottom portion  122   b . Other embodiments can have more or fewer portions and/or other arrangements (e.g., a left portion and a right portion). In the illustrated embodiment, the top portion  122   a  and the bottom portion  122   b  are configured to be coupled around a shaft using fasteners.  
         [0030]     The second shaft mount  122  can carry one or more electro-conductive material sections  123 . Four electro-conductive material sections are shown in the illustrated embodiment, as a first electro-conductive material section  123   a , a second electro-conductive material section  123   b , a third electro-conductive material section  123   c , and a fourth electro-conductive material section  123   d . The first and second electro-conductive material sections  123   a  and  123   b  are coupled to the top shaft mount section  122   a  and the third and fourth electro-conductive material sections  123   c  and  123   d  are coupled to the bottom shaft mount portion  122   b . In other embodiments, the conductor assembly can include more or fewer electro-conductive material sections  123  and/or other arrangements (e.g., the electro-conductive material sections  123  can be integral with the second shaft mount  122 ). When the second shaft mount  122  is coupled to the second shaft  121  (shown in  FIG. 2 ), the second shaft  121 , the second shaft mount  122 , and the electro-conductive material sections  123  can rotate as a unit.  
         [0031]     The split arrangement of the conductor assembly  120 , described above, can simplify handling, installation, and adjustment of the magnetic coupling system  100 . For example, the magnet rotor assembly  110  can be installed on to the first shaft  111  (shown in  FIG. 2 ). The first shaft mount  112  can be positioned on the first shaft  111  so that the end of the first shaft  111  is flush with a face of the first shaft mount  112 . The first shaft mount  112  can then be coupled to the first shaft  111  so that the conductor assembly  120  and the first shaft  111  can turn as a unit. In the illustrated embodiment, one or more shaft keys and an interference fit (e.g., the first shaft mount  112  is pressed onto the first shaft  111 ) are used to couple the first shaft  111  to the magnet rotor assembly  110 . As discussed above, in other embodiments, other methods (e.g., fasteners and/or set screws) can be used to couple the first shaft mount  112  to the first shaft  111 .  
         [0032]     The top portion  122   a  and bottom portion  122   b  of the second shaft mount  122  can then be positioned around the magnet holder  113 . The magnet rotor assembly  110  and the conductor assembly  120  can be configured so that when the second shaft mount  122  is positioned around the magnet holder  113 , the first shaft mount  112  and the second shaft mount  122  fit together to provide a selected amount of space between the magnet holder  113 , with the associated magnets  114 , and the electro-conductive material sections  123 . For example, a gapping tool or gauge can be inserted through the holes shown in the second shaft mount  122  to measure and/or adjust a gap between a portion of the second shaft mount  122  and the magnet holder  113  before the second shaft mount  122  is coupled to the second shaft  121 . In other embodiments, the magnetic coupling system  100  can use other methods for controlling/adjusting the gap between the magnets  114 /magnet holder  113  and the electro-conductive material sections  123  (e.g., a spacer element with a bushing centrally located between the magnet holder  113  or the first shaft mount  112  and the second shaft mount  122 ).  
         [0033]     Once the conductor assembly  120  is positioned relative to the magnet holder  113  and first shaft mount  112 , the second shaft mount  122  can be coupled to the second shaft  121  so that the second shaft  121  and the conductor assembly can turn as a unit. In the illustrated embodiment, one or more shaft keys and fasteners (e.g., fasteners that cause the first and second portions  122   a  and  122   b  of the second shaft mount  122  to tighten around the second shaft  121 ) are used to couple the second shaft mount  122  to the second shaft  121 . As discussed above, in other embodiments, other methods (e.g., an interference fit and/or set screws) can be used to couple the first shaft mount  112  to the first shaft  111 .  
         [0034]     As discussed above, with the magnet rotor assembly  110  coupled to the first shaft  111  and the conductor assembly  120  coupled to the second shaft  121  when a rotational force is imparted to one shaft the force can be transferred to the other shaft via the magnetic coupling system  100 . For example, if the first shaft  111  is rotated, the first shaft mount  112 , the magnet holder  113 , and the magnets  114  will rotate with the first shaft  111 . As the magnets rotate relative to the electro-conductive material sections  123 , magnetic friction will cause the electro-conductive material sections  123  to move. As the electro-conductive material section  123  moves the second shaft mount  122  will move, thereby moving the second shaft  121 .  
         [0035]     The position of the magnets  114  relative to the conductive material sections  123  can determine the strength of the magnetic friction and thereby the ability of the magnetic coupling system  100  to transfer rotational forces and/or motion between one shaft and the other. For example, increasing the space or gap between the magnets  114  and the electro-conductive material sections  123 , shown as a first gap  130   a  and a second gap  130   b  in  FIG. 3B , can reduce the strength of the magnetic friction between the magnets  114  and the electro-conductive material sections  123 . In other embodiments, the magnets  114  can be positioned to rotate so that only a portion of each magnet  114  passes between electro-conductive material sections  123  instead of the entire magnet  114  passing between electro-conductive material sections  123 , thereby reducing the strength of the magnetic friction between the magnets  114  and the electro-conductive material sections  123 .  
         [0036]     Other variables can also affect the strength of the magnetic friction between the magnets  114  and the electro-conductive material sections  123 . For example, the thickness of the electro-conductive material sections  123 , whether the electro-conductive material sections  123  are solid, laminated, or plated, and the number of magnets  114  can all affect the strength of the magnetic friction between the magnets  114  and the electro-conductive material sections  123 . Additionally, the material placed behind the electro-conductive material sections  123  can affect the strength of the magnetic friction. For example, if the electro-conductive materials sections  123  are copper and are backed by a ferrous material (e.g., at least a portion of the second shaft mount  122  is made of steel) the magnetic friction can be stronger than if the electro-conductive material sections  123  are backed by a non-ferrous material (e.g., aluminum and/or plastic).  
         [0037]     The manner in which the electro-conductive material sections  123  are positioned relative to each other can also affect the strength of the magnetic friction and/or the consistency of the magnetic friction as the magnet rotor assembly  110  and the conductor assembly  120  rotate. For example, if the first electro-conductive material section  123   a  and the third electro-conductive material section  123   c  are positioned such that they form a continuous ring around the first shaft mount  112 , as the magnet holder  113  rotates, the magnetic friction will be more consistent than if there is a gap between the first electro-conductive material section  123   a  and the third electro-conductive material section  123   c . The more consistent the magnetic friction is as the magnet rotor assembly  110  and the conductor assembly  120  rotate, the smoother the rotational force and/or motion can be transferred from one shaft to the other.  
         [0038]     Various methods can be used to position the electro-conductive material sections  123  to avoid gaps and/or to make combined electro-conductive material sections  123  appear to be more like a single electro-conductive material section  123  (e.g., make the combined sections appear to be more nearly homogenous) with respect to the magnetic friction created by the relative motion between the magnets  114  and the electro-conductive material sections  123 . For example, the edges between the electro-conductive material sections  123  where the electro-conductive material sections  123  meet and/or are joined (e.g., between the first electro-conductive material section  123   a  and the third electro-conductive material section  123   c ) can be configured to improve this characteristic. Depending on the materials used and the selected configuration, edges of adjoining electro-conductive material sections  123  can have various arrangements, including being straight cut, cut at corresponding angles to fit together, cut in saw tooth shapes that can interlock, cut to form a tongue and groove arrangement, and/or cut to have rounded shapes (e.g., one concave and one convex). In other embodiments, there may not be an edge joint (e.g., a solid, continuous ring/disk can be used).  
         [0039]     A feature of some of the embodiments described above is that the magnet rotor assembly and the conductor assembly of the magnetic coupling system can be handled as separate pieces, which makes handling and installation easier than with current systems. Additionally, even though the conductor assembly and the magnetic rotor assembly can be handled separately they can be easily adjusted once installed and/or during the installation process. Accordingly, an advantage of these features is that the easy handling, easy installation, and/or easy adjustment of the magnetic coupling system can save time and money during the installation and/or maintenance of these systems.  
         [0040]     Embodiments of the invention described above can be applied to a very wide variety of systems using a magnetic coupling or drive. For example, features of embodiments described above can be used in conjunction with selected embodiments and/or features described in U.S. Pat. Nos. 5,477,093; 5,477,094; 5,668,424; 5,691,587; 5,712,519; 5,473,209; and 4,826,150.  
         [0041]     The above-detailed embodiments of the invention are not intended to be exhaustive or to limit the invention to the precise form disclosed above. Specific embodiments of, and examples for, the invention are described above for illustrative purposes, but those skilled in the relevant art will recognize that various equivalent modifications are possible within the scope of the invention. For example, whereas steps are presented in a given order, alternative embodiments may perform steps in a different order. The various aspects of embodiments described herein can be combined and/or eliminated to provide further embodiments. Although advantages associated with certain embodiments of the invention have been described in the context of those embodiments, other embodiments may also exhibit such advantages. Additionally, none of the foregoing embodiments need necessarily exhibit such advantages to fall within the scope of the invention.  
         [0042]     In general, the terms used in the following claims should not be construed to limit the invention to the specific embodiments disclosed in the specification unless the above-detailed description explicitly defines such terms. In addition, the inventors contemplate various aspects of the invention in any number of claim forms. Accordingly, the inventors reserve the right to add claims after filing the application to pursue such additional claim forms for other aspects of the invention.