Patent Publication Number: US-6669024-B2

Title: Sweeper magnet

Description:
FIELD OF THE INVENTION 
     The present invention generally relates to pick-up tools and, more particularly, to sweeper magnets. 
     BACKGROUND OF THE INVENTION 
     Conventional sweeper magnets typically include a magnet assembly attached to an elongate handle. The magnet assembly includes a base adapted for attachment to the handle and a magnet attached to the base. During use, the magnetic sweeper is positioned in sufficient proximity to a pick-up surface so that the magnet attracts magnetic debris on the surface. The magnetic debris is pulled to the surface of the magnet or a magnet cover plate, and is subsequently removed, often manually. 
     Such conventional magnetic sweepers are overly difficult and cumbersome to use. Care must be taken to insure that the magnet assembly is spaced a proper distance from the pick-up surface. If the magnet assembly is spaced too far, the magnetic debris will not be attracted to the magnet. On the other hand, if the magnet assembly is spaced too close to the pick-up surface, there will be insufficient clearance to place the magnet assembly over the magnetic debris. Accordingly, in order to achieve the proper spacing, a user must manually support the magnetic sweeper at a proper distance above the pick-up surface. 
     Some magnetic sweepers are known which include wheels for supporting the magnet above the pick-up surface. These sweepers are typically large, as far as magnet pick-up tools are concerned, and the wheels are usually placed on outside ends of the magnet assembly. Accordingly, such magnetic sweepers are unsuitable for retrieving magnetic debris from pick-up surfaces having minimal clearance. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a top perspective view of a sweeper magnet constructed in accordance with the teachings of the present invention. 
     FIG. 2 is a bottom perspective view of the sweeper magnet of FIG.  1 . 
     FIG. 3 is an exploded perspective view of the sweeper magnet of FIGS. 1 and 2. 
     FIG. 4 is a side elevation view of a cover provided with the magnet sweeper of FIGS. 1-3. 
     FIG. 5 is an enlarged detail of a portion of the cover of FIG.  4 . 
    
    
     DETAILED DESCRIPTION 
     An exemplary sweeper magnet  10  constructed in accordance with the teachings of the present invention is illustrated in FIGS. 1-5. The sweeper magnet  10  may be used to collect magnet debris from a pick-up surface. As used herein, “magnetic debris” refers to any object formed of ferromagnetic material that may be retrieved by a sweeper magnet, such as screws, paperclips, and the like. Furthermore, “pick-up surface” refers to any surface on which magnetic debris may be deposited. 
     The sweeper magnet includes a base assembly  12  attached to a coupling  16  adapted for removable attachment to an elongate handle (not shown). The coupling  16  may include internal threads (not shown) that mate with external threads provided on the handle. The internal threads may be of a standard size so that the coupling  16  may be removably attached to standard handles of various lengths. 
     The base assembly  12  includes a base  18  pivotably attached to the coupling  16  (FIG.  1 ). For example, the base  18  may include a boss  20  sized for insertion into a yoke  22  formed at an end of the coupling  16 . A bolt  24  may then be inserted through holes formed in the boss  20  and yoke  22  and secured by a fastener  26 . Accordingly, the coupling  16  may rotate with respect to the base  18  about the bolt  24 , and the coupling  16  may be secured in selected angular positions with respect to the base  18  by tightening the fastener  24 . 
     As best shown in FIGS. 1 and 3, the base  18  includes a cylindrical side wall  28  depending from a periphery of a top wall  30  to define a cup recess  32 . A mounting cup  34  is sized for insertion into the cup recess  32  and, in turn, defines a magnet recess  36 . A magnet, such as annular magnet  38 , has an outside diameter  40  sized for insertion into the magnet recess  36 . The magnet  38  has a first surface  39  adapted for attachment, such as with an adhesive, to the mounting cup  34 , and an exposed second surface  41 . The magnet  38  and attached mounting cup  34  form a cup magnet assembly  42  that may be inserted into the cup recess  32  and attached to the base  18 , also preferably with an adhesive. 
     The base  18  and coupling  16  are preferably formed of a plastic (e.g., ABS or nylon) or similar material that is easily molded into an attractive design, while the mounting cup  34  is made of a metal material. 
     A magnet cover  44  is positioned over a bottom face  46  of the magnet  38 . The cover  44  is generally circular and has an outside diameter  46  sized to closely mach an outside diameter of the mounting cup  34 . The cover  44  may be secured in any known manner. In the exemplar embodiment, the cover  44  is formed of a ferromagnetic material, so that the magnetic field generated by the magnet  38  holds the cover  44  in place. 
     The cover  44  includes a projection, such as bubble  46 , for automatically spacing the magnet  38  from a pick-up surface. In the illustrated embodiment, the bubble  46  is formed in a central portion of the cover  44 , so that the cover  44  has a generally planar annular portion  48  extending about a periphery of the bubble  46 . As best shown in FIG. 4, the bubble  46  has a height H so that, when the sweeper magnet  10  is placed on a pick-up surface, at least a portion of the cover  44  is spaced from the pick-up surface by a distance equal to at least the height H. The height H is selected so that it creates sufficient clearance between the planar cover portion  48  and the pick-up surface for common types of magnetic debris. In an exemplary embodiment, the height H is approximately 0.25 inches. 
     A transition area  50  of the cover  44 , between the planar portion  44  and the bubble  46 , may be formed with a gradual slope so that the bubble  46  does not snag or catch on the pick-up surface. As best shown in FIG. 5, the transition area  50  is formed with a radius r, which may be approximately 0.1 inches. Furthermore, the bubble  46  is formed with a continuous curve to avoid the formation of sharp edges or other profiles that may snag or damage the pick-up surface. As best shown in FIG. 4, the bubble  46  has a dome-like shape with a constant radius R, which may be on the order of approximately 0.5 inches. 
     Although certain apparatus constructed in accordance with the teachings of the invention have been described herein, the scope of coverage of this patent is not limited thereto. On the contrary, this patent covers all embodiments of the teachings of the invention fairly falling within the scope of the appended claims either literally or under the doctrine of equivalents.