Patent Publication Number: US-2003229974-A1

Title: Concealed secure magnetic clasp

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
     [0001] This application claims priority in U.S. provisional application serial No. 60/389,358, filed on Jun. 15, 2002. 
    
    
     
       FIELD OF THE INVENTION  
       [0002] The present invention relates to magnetic clasps and, more particularly, relates to a concealed secure magnetic clasp for jewelry.  
       BACKGROUND OF THE INVENTION  
       [0003] Jewelry is generally very costly. Many types of jewelry, such as bracelets and necklaces, include fastening devices and/or closures that affix one end of an open loop to another to close the loop. The security and reliability of such fastening devices and/or closures are important factors in the value of the jewelry. Nearly all solutions in the jewelry industry involve solid mechanical clasps, clips, loops, snaps, buckles, threaded assemblies, and the like. For a variety of reasons, only a very few effect fastening and closure through the use of magnetic attraction.  
       [0004] Known magnetic clasp assemblies in the jewelry industry involve a variety of self-aligning, butted, conical, round, square, rectangular, and tubular designs. Some are mechanically simple configurations while others are mechanically complex configurations. Magnetic clasp assemblies are also used in applications other than jewelry, but the jewelry industry and its market places special importance upon attributes such as appearance that are not necessarily significant in those other fields. All prior art configurations, whether jewelry-related or not, involve considerable compromises.  
       [0005] One problem with existing magnetic jewelry clasps is their appearance. The appearance of the magnetic fixture may detract from the appearance of the item of jewelry. The appearance of a magnetic clasp, in turn, may give rise to security concerns. An observer may see that two ends of a strap, rope, belt, or strand are held together only by a magnetic fixture, and may correctly assume that they are separable with no more than a simple tug. To alleviate this concern, additional mechanical affixing devices such as loops, snaps, and clips are often employed, which virtually eliminate the fundamental advantage of the magnetic closure.  
       [0006] Another problem with magnetic clasps, especially those in which magnetic surfaces are butted together in the simplest way, is that attraction (and therefore security) is greatest by far when the two surfaces are perfectly parallel and in uniform contact across their respective common planar surfaces. Any partial dislodgment or relative tipping of the two components that damages the perfection of that contact, however slightly, greatly reduces the attractive force and increases the likelihood that the components will separate. The total area of contact also determines the security of the connection, and any lateral movement or sliding of one surface with respect to the other, even while maintaining perfection of the common planar surface, reduces attraction and increases the probability of separation. Hence, the ability of the secured components to move relative to each other increases the probability of complete separation and loss of the jewelry.  
       [0007] Another problem with existing magnetic jewelry clasps is their size and bulk. Because the mass required to maintain adequate security of the fastening system is rarely consistent with the aesthetic intent of the designer, compensatory design features and compromises are usually required. These and other attempts to overcome deficiencies in the concept have led to increased manufacturing costs. Execution in general has grown from simple to very complex, with a commensurate increase in manufacturing costs.  
       [0008] While many of the prior art magnetic clasps may be suitable for the particular purposes for which they are intended, they are not optimum solutions for jewelry and other applications, and generally involve a variety of compromises in aesthetics, functionality, ease of use, security, and cost of manufacture. The concealed secure magnetic clasp of the present invention substantially departs from and has substantial advantages over the conventional concepts and designs of the prior art.  
       SUMMARY OF THE INVENTION  
       [0009] In view of the foregoing disadvantages inherent in known methods and mechanisms for magnetically connecting elements of jewelry and other items, the present invention provides a new and superior method and mechanism that is aesthetically pleasing, secure, easy to use, and inexpensive to manufacture.  
       [0010] One object of the invention is to enable two ends of a rope, loop, band, belt or other item to be affixed one to the other using a magnetic closure in a unique manner that avoids the problems of prior art.  
       [0011] Another object of the invention is to provide a magnetic closure with an outer housing having dimensions that force the alignment of the magnetic faces of the two ends, thereby maximizing parallelism and the magnetic bond, and minimizing security risk.  
       [0012] Another object of the invention is to provide a magnetic closure for jewelry having a decorative outer housing that is a major aesthetic feature of the jewelry, thus rendering the magnetic nature of the closure less obvious.  
       [0013] Another object of the present invention is to provide a magnetic closure that is economical to manufacture using simplified and low-cost components and assembly techniques.  
       [0014] Another object of the invention is to provide a magnetic closure for jewelry that is easy to use, minimizing the need for manual dexterity while maximizing security.  
       [0015] Another object of the invention is to provide a magnetic closure that optionally integrates an intrinsic mechanical lock, achieved without additional moving parts and by using the magnetic attraction of the clasp components to effect a mechanical lock. The optional mechanical lock is simple and easy to use and provides security beyond that of the magnetic clasp itself.  
       [0016] Another object of the invention is to provide a magnetic closure for jewelry that is optionally configured to minimize the magnetic field of the assembly, thus reducing the likelihood of attracting ferrous detritus in the environment.  
       [0017] Another object of the invention is to exploit health advantages of magnetic devices, insofar as any exist, by adding magnetic materials to a jewelry item, and thus generating magnetic fields.  
       [0018] Accordingly, one embodiment of the invention is a jewelry clasp including a magnetic clasp assembly. A first magnetic component has a first mating face and is affixed to a first free end of a band, and a second magnetic component has a second mating face and is affixed to a second free end of the band. A housing is affixed to the second free end of the band and defines a recess for insertion of the first free end. The housing conceals the first and second magnetic components when the magnetic clasp. assembly is engaged, and is configured with internal dimensions that force optimal alignment of the first and second mating faces. In one implementation, the clasp further includes a mechanical lock that is engaged and maintained with the help of the magnetic attraction provided by the magnetic clasp assembly.  
       [0019] Another embodiment of the invention is a clasp for an item of jewelry. A housing is attached to a first free end of a jewelry band and defines a receptacle for receiving a second free end of the jewelry band. A detent is formed within the receptacle, and a first magnetic component is embedded in and flush with an interior surface of the receptacle. A second magnetic component is attached to the second free end of the jewelry band and is configured to engage and mate with the first magnetic component in a parallel and uniform area of contact to establish a magnetic lock. A hook is attached to the second free end of the jewelry band and is configured to fit within the detent to establish a mechanical lock.  
       [0020] Other embodiments, features, objects and advantages of the invention will be apparent to one of skill in the art upon examination of the following figures and detailed description. It is intended that all such additional embodiments, features, objects and advantages be included within this description, be within the scope of the invention, and be protected by the accompanying claims. 
     
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
     [0021] The components in the figures are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the invention. In the figures, like reference numerals designate corresponding parts throughout the different views.  
     [0022]FIG. 1 is a perspective view of an item of jewelry including a magnetic clasp according to the present invention.  
     [0023]FIG. 2 is a side elevation view of the item of jewelry of FIG. 1.  
     [0024]FIG. 3 is a partial, enlarged top view of the item of jewelry of FIG. 1 showing operation of the inventive magnetic clasp.  
     [0025]FIGS. 4 a - 4   c  illustrate incremental stages of coupling a second embodiment of a magnetic clasp according to the present invention.  
     [0026]FIGS. 5 a - 5   c  illustrate incremental stages of coupling a third embodiment of a magnetic clasp according to the present invention.  
     [0027]FIG. 5 d  illustrates a fourth embodiment of a magnetic clasp according to the present invention. 
    
    
     DETAILED DESCRIPTION  
     [0028] FIGS.  1 - 3  depict an item of jewelry  10  fitted with a concealed secure magnetic clasp assembly  20  according to the present invention. Jewelry  10  may be a bracelet (illustrated), watchband, medical sensor or any other wearable item. Although a bracelet  10  is illustrated, it should be understood that the particular embodiment shown in FIGS.  1 - 3  is for illustrative purposes only and that this invention is not so limited.  
     [0029] Bracelet  10  comprises a band having two free ends that are secured together by magnetic clasp assembly  20  to form a loop around the wearer&#39;s wrist. In the illustrated embodiment, the bracelet band comprises a series of stranded, twisted or braided cables  12  bound together by clamps  14 . Clamps  14  serve the utilitarian function of arranging and maintaining cables  12  in a band configuration, and may (optionally) serve a decorative function as well. Again, it should be understood that bracelet  10  is depicted for illustrative purposes only and that many other embodiments are possible and within the scope of this invention. The bracelet band could be formed from a continuous flexible material, for example, rather than from stranded cables that are clamped together. Metal, leather, fiber or any other material that achieves the desired functional and visual effects may be used. In particular, the term “band” as used herein should be understood to cover any rope, loop, band, belt or any other item including two free ends that may be attached by a clasp.  
     [0030] Magnetic components  22  and  24  are affixed to the free ends of bracelet  10 . The magnetic components may be swaged, soldered, welded, crimped, or affixed in any other appropriate manner to the free ends of bracelet  10 . In the illustrated embodiment, magnetic components  22  and  24  are affixed to the bracelet ends by fittings  26  and  28 . As best seen in FIG. 3, a housing or sleeve  30  is affixed to one free end of the bracelet. Housing  30  surrounds the magnetic component  24  of the bracelet end to which it is affixed, and is configured with an opening  32  and recess  34  to permit insertion of the opposite cable end and its magnetic component  22 . Housing  30  and magnetic components  22  and  24  define clasp assembly  20 , which preferably (and as illustrated in FIGS.  1 - 3 ) has a rectangular cross-section.  
     [0031] The elasticity of bracelet  10  tends to place magnetic component  22  in the proximity of housing  30 . When inserted through opening  32  and into recess  34 , magnetic components  22  and  24  attract and cling to each other to establish a bond. As best seen in FIGS. 1 and 2, housing  30  completely conceals magnetic components  22  and  24 . Hence, components  22  and  24  are not outwardly visible and do not detract from the aesthetic appearance of bracelet  10 . Housing  30  may optionally be embellished with design features  36  such as jewels, gems, carving, inlays, artwork or other features such that it is a dominant and desirable visual feature of bracelet  10 .  
     [0032] Magnetic components  22  and  24  and housing  30  are oriented in order to maximize the strength of the bond. Each of components  22  and  24  preferably has a relatively flat mating surface, and when butted together, are preferably oriented such that the two mating surfaces are perfectly parallel and in uniform contact across their respective common planar surfaces. The plane of contact between the mating surfaces of components  22  and  24  is approximately perpendicular to a plane passing through and parallel with the jewelry band. In alternative configurations, a more rounded shape may be used in order to provide greater flexibility.  
     [0033] Housing  30  is shaped and configured with internal dimensions and tolerances that force optimal alignment of the two magnetic faces. Flat/rectangular dimensions are preferred (as illustrated), but other shapes such as square, round, oval, triangular or any other shape consistent with the objective of achieving good alignment of the mating magnetic surfaces may be used. Any partial dislodgment or relative tipping of the two magnetic components that damages the perfection of their contact, however slightly, greatly reduces the attractive force and increases the likelihood that the components will separate. The total area of contact also determines the security of the connection, and any lateral movement or sliding of one surface with respect to the other, even while maintaining perfection of the common planar surface, reduces attraction and increases the probability of separation. Hence, housing  30  is configured to inhibit lateral sliding and angular changes that would reduce the magnetic effect.  
     [0034] The strength of the bond is also dependent on the magnetic materials comprising the mating surfaces of components  22  and  24 . One mating surface may be magnetically polarized, while the other is a magnet or a magnetically permeable substance. Suitable magnetic materials include neodymium (preferred), cobalt-samarium, ticonal, and any other permanent magnet materials that achieve a satisfactory combination of bond strength and mass. The other components of bracelet  10  (housing, band, etc.) may be made of any functionally and visually appropriate material.  
     [0035]FIGS. 4 a - c  illustrate a second embodiment of the invention employing a mechanical lock to supplement the magnet lock. Preferably, the magnetism provided by the magnetic lock is advantageously employed to help engage the mechanical lock. Clasp assembly  40  is configured to connect and secure the free ends  42  and  44  of an item of jewelry such as a bracelet. Although only the clasp assembly itself is depicted in FIGS. 4 a - c,  it will be understood that clasp assembly  40  is a part of an item of jewelry such as bracelet  10  depicted in FIGS.  1 - 3  (i.e., clasp assembly  40  would replace clasp assembly  20 ). Magnetic component  46  is affixed to free end  42 , and magnetic component  48  is affixed to free end  44 . Housing  50  is also affixed to free end  44 , surrounding magnetic component  48  and defining a receptacle  52  for insertion of free end  42 .  
     [0036] Mechanical lock  58  is defined by a groove or detent  54  milled into one side of housing receptacle  52  and configured to mate with a corresponding projection or hook  56  formed on one side of magnetic component  46 . Mechanical lock  58  supplements the magnetic lock  47  formed by the attraction of components  46  and  48 . As shown in FIGS. 4 a - b,  housing  50  is configured such that free end  42  must be inserted at an angle in order to allow hook  56  to engage detent  54 . A radius  60  is cut into the interior side of housing  50  opposite lock  58  to facilitate this angular insertion. The opening  62  of housing receptacle  52  may also be beveled to further facilitate this angular insertion.  
     [0037] Once hook  56  is past detent  54 , free end  42  is straightened and elastically returns to its straight orientation within housing  50  to permit mating of the flat opposing surfaces of magnetic components  46  and  48  (FIG. 4 c ). Magnetic components  46  and  48  are preferably oriented such that their mating surfaces are perfectly parallel and in uniform contact across their respective common planar surfaces, and housing  50  is shaped and configured with internal dimensions that force optimal alignment of the two magnetic faces. In particular, housing  50  is configured to inhibit lateral sliding and angular changes that would reduce the magnetic effect.  
     [0038] The magnetic attraction between components  46  and  48  preferably helps to “pull” free end  42  into a straightened position and hence may help to engage and maintain mechanical lock  58 . In order to further strengthen the magnetic bond and to help engage and maintain the mechanical lock, additional mating side magnets  64  and  66  may optionally be embedded in the free end of the band and the interior of sleeve  30 . To disengage clasp assembly  40 , free end  42  must be distorted such that it exits housing  50  at the same angle as it entered.  
     [0039]FIGS. 5 a - c  illustrate a third embodiment of the invention which also employs a mechanical lock to supplement the magnet lock. Clasp assembly  70  includes a sleeve or housing  72  permanently affixed to one end  74  of a bracelet band or belt. A hook detent  76  is milled into the upper surface  77  of the housing cavity  78 , and a flat magnet  80  is embedded in upper surface  77  such that it is flush with surface  77 . The opposite (free) end  82  of the bracelet band is swaged, soldered or otherwise permanently bonded to a fixture  84 . Fixture  84  has a hook  86  formed at its end that is configured to engage in hook detent  76 , as well as a flat magnet  88  embedded in its upper surface that is configured to mate with magnet  80  embedded in sleeve  72 .  
     [0040] When free end  82  is inserted into sleeve  72  (FIG. 5 b ), magnets  86  and  88  mutually attract, moving fixture  84  laterally, pulling hook  86  into detent  76  and providing a secure mechanical and magnetic lock (FIG. 5 c ). The plane of engagement between magnets  86  and  88  is not perpendicular to a plane passing through the plane of the jewelry belt, but rather, is at a slight angle to and closer to being parallel with the plane of the jewelry belt. Magnets  86  and  88  are preferably oriented such that their mating surfaces are perfectly parallel and in uniform contact across their respective common planar surfaces, and housing  72  is shaped and configured with internal dimensions that force optimal alignment of the two magnetic faces. In particular, housing  72  is configured to inhibit lateral sliding and angular changes that would reduce the magnetic effect.  
     [0041] To release the lock requires that free end  82  be slightly lifted at a point prior to sleeve  72 , levering end fixture  84  into the position shown in FIG. 5 b  and permitting withdrawal. A slightly modified embodiment is illustrated in FIG. 5 d,  in which the sleeve is configured with a thickness to house a functional or ornamental device  90  such as a watch movement. Any thickness is within the scope of the invention, so long as sufficient space is permitted for the latch assembly.  
     [0042] While various embodiments of the invention have been described, it will be apparent to those of ordinary skill in the art that many more embodiments and implementations are possible that are within the scope of this invention.