Patent Publication Number: US-2023149823-A1

Title: Magnet holder and system

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     The present application claims the benefit of U.S. application Ser. No. 16/372,842 filed Apr. 2, 2019, entitled MAGNET HOLDER AND SYSTEM, which is allowed. 
    
    
     BACKGROUND OF THE INVENTION 
     Magnet holder inserts are used in a wide variety of applications providing a means of attaching one or more objects together with a reasonable amount of magnetic bonding strength. Most magnet holder inserts require the addition of some type of a protective outer coating or cover to protect the magnets themselves from physical damage and keep the magnets in place. U.S. 2016/0145925 is an example of such a holder with a screw on cap to lock the magnet in position in the holder. The holder includes external ribs which help hold the holder in position within an opening or hole in the article to which the magnet is to be attached. 
     U.S. 2006/01101010 discloses in  FIGS.  27 ,  28  and  29    a cylindrical magnet holder having a top wall  200   a  and an open bottom through which a magnet  110   b  can be inserted into the holder. The holder is inserted into a hole in the article with the top wall, preventing escape of the magnet, and barbs  252   b  on the exterior of the cylindrical wall of the holder holding it in place in the receiving hole of the article. 
     Other magnet holders are typically made by either gluing the magnets into a protective holder and then gluing it onto or into an object to create a final part or they use a screw or shank type fastening system with a protective head which is attached through a hole in the magnet into the final part. (e.g. 5681202). In many of these cases there are extra steps and costs added to the assembly process and the potential for unplanned assembly failures in finished parts under normal use. In cases where the magnets are attached to the finished part using a shank type fastening element a hole in the magnet is required to allow the shank to pass through it, the presence of a hole in the magnet will change the magnetic field pattern and can significantly reduce the magnetic field strength. 
     In other cases where adhesive methods are used to build the magnet holder insert and/or final assembly, there are significant hurdles related to maintaining proper adhesion over time due to the dissimilar nature of the materials involved. In many cases the body of the finished part may be fabricated from cellulosic wood materials, while the magnet may be a ferrite powder mixed in a rubber or polymer matrix, and the protective covering feature made from an engineered plastic material. 
     SUMMARY OF THE INVENTION 
     The present invention relates to magnet holders for use in mounting magnets in furniture, toys, containers, boxes, and the like. The magnet holder of the present invention comprises hollow housing with a top wall, a side wall or walls, and an open bottom through which a magnet can be inserted. The internal surface of the hollow housing is designed with at least one or more inwardly projecting retainers designed to allow the magnet to be press fit fully into the housing and held firmly in place during assembly and normal use. A single retainer includes space to either side, and multiple retainers are spaced so that air passes through said spaces as a magnet is pressed into position past said retainer or retainers. The external surface of the hollow housing side wall is also designed with multiple ribs, preferably with spaced gaps therein, which allow the magnet holder assembly to be easily press fit into a finished part and held firmly in place during normal use. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Potential configurations of the invention are illustrated in the included drawings by way of example and not by way of limitation in the figures of the drawings. 
         FIG.  1    is a side cutaway view showing a magnet holder inserted into round finished part; 
         FIG.  2    is a perspective view of a cylindrical housing for the magnet holder insert prior to insertion; 
         FIG.  3    is a lateral cross-sectional view showing a cylindrical housing for the magnet holder; 
         FIG.  4    is a bottom view of a cylindrical housing for the magnet holder; 
         FIG.  5    is an exploded view of the cylindrical housing and cylindrical magnet prior to assembly; 
         FIG.  6    is a lateral cross-sectional view of the magnet holder housing with magnet positioned therein; 
         FIG.  7    is a sectional view of the magnet holder with a domed top; 
         FIG.  8    is a close-up view of the cylindrical housing side wall features; 
         FIG.  9    is an exploded view of a toy car with multiple magnet containing magnet holders deployed for insertion into bores located at various points on the toy; 
         FIG.  10    is a side elevation of the housing; and 
         FIG.  11    is a side elevation of the housing turned one quarter turn from the view shown in  FIG.  10    and showing a larger inwardly sloping angle on the reverse sloped retainer rings  15 . 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMODIMENT 
     The magnet holder of the preferred embodiment comprises a hollow molded plastic housing  10 , preferably cylindrical in shape with a top  11 , cylindrical side wall  12 , and an open bottom  13  through which a circular disk magnet  20  can be inserted. ( FIGS.  1  and  3   ) The terms top and bottom refer to the orientation of the components as shown in the drawings, rather than spatial orientation in use, which will vary. The terms holder and housing are used interchangeably and are identified by the numeral  10 . In  FIG.  1    magnet ( 20 ) has been press fit into the bottom of housing ( 10 ) to form a magnet holder insert  10 / 20 , which as shown is press fit into an article ( 30 ). It could be press fit into any article for which magnetic action is desired, e.g. a block or body of a toy, or an article of furniture to provide a magnetic door latch, etc. The term “magnet holder insert  10 / 20 ” is used herein to refer to the housing  10  with magnet  20  inserted therein. The article can be of any solid substrate (e.g. wood, plywood, MDF, plastic, metal, composite, drywall. etc. materials). 
     The cylindrical side wall exterior ( 12 ) includes at least one, preferably two to four, and most preferably three reverse sloped retainer rings ( 15 ) designed to allow the magnet holder to be press fit into receiving holes/cavities  32  in article  30  and provide structural integrity to keep holder insert  10 / 20  in place and stable under normal use of article  30 . ( FIGS.  1 ,  3 ,  8  and  11   ) The angle on the reverse slope of retainer rings  15  can vary. In  FIG.  11   , the angle on retainer rings  15  slopes inwardly more to facilitate ease of locating the housing in the receiving opening  32  intended for it. The housing can be located a bit off center and still enter receiving opening  32 . The housing then centers itself in opening  32  as it is pressed into place. 
     There are also at least one, preferably at least four, and most preferably eight spaced gaps ( 16  and  16   a ) in the retainer rings ( 15 ) to allow for air to escape from the inside of the cylinder when the magnet holder insert  10 / 20  is press fit into position in a receiving hole  32  in article  30 . ( FIGS.  1 - 4 ,  10  and  11   ) Gaps  16  are relatively narrow notches formed in rings  15 . Gaps  16   a  are formed on opposite sides of housing  10  as flats in the otherwise circumferential perimeter of rings  15 . These flats make gaps  16   a  shallower than gaps  16 , but somewhat wider, even though still relatively narrow. (Compare  FIGS.  10  and  11   .) The flats forming gaps  16   a  provide a flat gripping surface on opposite sides of housing  10 , making it possible for holders  10  to be gripped at the opposite flats and given a desired location and spatial orientation. Preferably, the gaps  16  and  16   a  in the successive rings are aligned vertically with one another. ( FIGS.  2  and  4   ) As can be seen in  FIG.  4   , eight of said gaps  16  and  16   a  are uniformly spaced around said retainer rings. The rings  15  are continuous around side wall  12 . The gaps occupy from about 10% to about 20% of the linear perimeter of each ring  15 . The dimensions, e.g. inner diameter of a receiving insert hole  32  is just slightly smaller than the outer diameter of rings  15 , such that a force fit is required to insert the holder inserts  10 / 20  into a hole  32 . Representative dimensions are as follows: Inner diameter of hole  32  of 10 mm, and outer diameter of rings  15  of 10.20 mm. 
     There is at least one, and preferably at least two spaced retainers ( 14 ) positioned on the smooth inside surface of the cylindrical housing wall  12  hold magnet  20  in place following assembly into the interior of housing  10 . ( FIGS.  1 ,  3  and  8   ). The interior dimensions, e.g. diameter, of 1 housing  10  are/is just slightly greater than the outer dimension of magnet  20 , at least in vicinity of said retainers  14 , and said retainers project inwardly a distance which extends slightly beyond the outer dimension of magnet  20 . Preferably the spacing  17  between, wall  12  and the perimeter of magnet  20  is uniform throughout, except for the inward protrusion of retainers  14  extending inward from the inner surface of wall  12  and beyond the perimeter of the magnet. (However, the spacing dimension could be greater in areas remote from retainers  14 .) Exemplary dimensions for the interior of the housing, the diameter of the magnet, and the distance of projection of retainers  14  are as follows: 
     Outer diameter of magnet  20  of 6.00 mm, an inner diameter of housing wall  12  of 6.10 mm, and retainer  14  extending 0.10 mm inward from the inner housing wall  12 . Preferably, at least two of said retainers are generally opposite one another on said inner wall, such that the distance between them is slightly narrower than the diameter of a magnet  20  to be inserted between them. In this example, the diameter of magnet  20  is 6.00 mm, and the distance between said at least two retainers is 5.9 mm, thus providing support for said magnet  20  when it has been inserted past them and is located above them. 
     As a result, magnet  20  can be pressed into the housing through the bottom opening ( 13 ), over and past the retainers  14 . The retainers  14  are not continuous around the circumference of the housing, allowing space to either side of the retainers for air to escape around the perimeter of the magnet  20  past a single retainer or between multiple retainers  14  through spacing  17  between the magnet  20  and the inside surface of the cylindrical housing wall  12  as magnet  20  is pressed into position. Two or more retainers  14  provide for a secure fit of the magnet  20  against the bottom of the top wall  11  during normal use conditions. In the preferred embodiment a total of four retainers  14  are symmetrically placed to provide for adequate air escape openings while maintaining stable magnet placement. The preferred shape of this retainer  14  is such that it allows for a secure snap fit effect when the magnet  20  is press fit into the housing  10 . 
     The shape of projecting retainers can vary. In a preferred embodiment, retainers  14  are inwardly projecting dimples. 
     The top wall  11  acts as the positioning stop for the magnet and is designed to keep the magnet in place and protect the magnet from physical damage. ( FIGS.  1  and  3   ). Preferably, the dimensions of the housing interior from retainers  14  to top wall  11  are such that when magnet  20  is pressed into the housing  10  it contacts top wall  11  of the housing, and rests against retainers  14 , which holds magnet  20  firmly in place and prevents it from rattling around in housing  10  interior in use. ( FIGS.  1   ). 
     The top wall  11  of housing/holder  10  is designed to be thick enough to hold the magnet in place within housing  10 , and to protect the magnet surface, and thin enough that a smaller magnet can be used to achieve the same attractive force of a larger magnet behind a thicker wall The thickness of the top wall  11  is typically only 0.5 millimeters thick and is made of a plastic material which is not magnetic. A thinner top wall  11  means the magnet  20  will be closer to the outer surface of top wall  11  and the magnet  20  can be a smaller magnet and yet achieve the same attractive force of a larger magnet behind a thicker wall. The wall  11  thickness is optimally determined based on a) the structural strength requirements, based on the intended application and the insert  10  material selection, and b) the magnet  20  strength. There is a desire to optimize the magnet  20  and insert  10  materials to minimize part costs while maintaining ease of assembly and finished durability. 
     Housing  10  is preferably made of a rigid but slightly resiliently compressible plastic material, such that exterior rings  15  compress/flex slightly as the magnet holder insert  10 / 20  is press fit into position within a hole/cavity  32  formed or drilled into the article  30  for receiving the magnet holder insert. In the preferred embodiment shown, the hole/cavity is a cylindrical hole having a diameter slightly smaller than the diameter of the rings  15 , such that rings  15  compress and/or deflect somewhat as holder insert is pressed into the hole/cavity. This provides an adhesive free fit of the holder insert into article  30 . The depth of said holes are typically equal to, or slightly deeper than the length of the housing side wall  12 . Preferably, the depth of the hole is essentially the same as the length of the housing side wall  12 . 
     Similarly, the slightly resiliently compressible plastic material allows the cylindrical wall  12  to flex slightly, and/or retainers  14  to compress slightly, as magnet  20  is pushed past them and into position within housing  10 . An exemplary plastic material is: ABS plastic with UV stabilizers. 
       FIG.  7    shows an alternative embodiment housing  10  designed with a top wall  11   a  that is slightly convex. There are many situations where it is desirable to provide some degree of freedom of movement between the magnet holder insert and the surface to which it is attached. In such situations a slightly convex shaped top wall  11   a  which protrudes outward from the finished part  30  surface can be used to allow the finished part to stay in direct contact with another solid surface, such as a magnetic part with opposite polarity or a surface susceptible to magnetic attraction, even if the finished part is not directly aligned with the contacted solid surface. This is a desirable feature in moving parts, such a magnetic coupling between two or more finished parts, where it is important to maintain contact even when alignment between the parts varies in either the horizontal or vertical plane. Top wall  11   a  also typically extends a little beyond side-wall  12  at rim  11   b , which serve as a stop against the top surface of article  30  during insertion into surrounding hole  32 . The flat surface of a punch tool used to insert holder  10  with top  11   a  can&#39;t push holder  10  too far into hole  32  because rim  11   b  won&#39;t let it. Where top wall  11  is flat, it does not have to have a surrounding rim to limit depth of insertion. A flat punch can be used which is larger in diameter than holder  10 , such that engagement of the edges of the punch with the top surface of article  30  limits further insertion of holder  10 . 
       FIG.  9    shows an exploded view example of one embodiment of this invention. Presented is an assembly view of a toy wagon  30   a  capable of being magnetically coupled to one or more other toy wagons, and capable of carrying on its top up to  3  separate toy components with a magnetically affected surface. The wagon  30   a  has a body  31  supported by wheels  33  having axle stems  34  which can be pressed into axel holes  35  in the sides of body  31 . 
     Three holes  32  are formed or drilled into the top of body  31 , and another hole  31  is formed or drilled into each end of body  31 . Three magnet holder inserts  10 / 20  are inserted into top holes  32 . Another insert  10   a / 20 , but with a domed/convex top  11   a  is inserted in an end hole at each end of body  31 . This allows this toy part to remain directly connected to a second toy part, of opposite magnetic polarity even if the toy parts do not stay perfectly aligned during use. In situations where a series of directly connected toys are on a track which has turns or is not perfectly aligned the convex top  11   a  provides a significant degree of freedom to accommodate such design elements without losing direct contact. Using a convex shape rather than a simple half round shape allows for degree of freedom compensation in both the horizontal plane and the vertical plan simultaneously. 
     On this toy example, the top surface of the toy body  31  is intended to have other toy components stacked on top of toy  30   a . In this case it is desirable to use the flat top  11  holder which aligns flush with the top surface of the toy such that any flat surfaced object with magnetic tendencies can become directly attached to the magnet holder  10  surface. 
     There may also be cases where a specific alignment of two mating surfaces is desired. In such cases the magnetic housing top  11  can be constructed with a various ridge style patterns, and the mating part constructed with a reverse image of said ridge style pattern, such that when the two are coupled they remain in a specific alignment configuration until sufficient force is applied to break the magnetic coupling. 
     Because of the present invention, an article such as a toy, furniture or the like can be fitted with magnets using the magnet holder inserts of the present invention. The retainers on the interior wall allows magnets to be easily inserted into the holder and held in place without adhesive. Similarly, the external ribs on the housing with air passage spacings therein allow the magnet holder insert to be easily force fit into a receiving aperture in the article, which in turn is held in place without adhesive. 
     The forgoing is a description of exemplary preferred embodiments of the invention, and it is to be understood that variations thereof can be used without departing broader concepts and spirit of the invention.