Abstract:
A sandpaper disk is formed having an exterior diameter and a central open area forming a ring shaped sandpaper disk. This is attached to a random orbital sander by an interface pad which separates the sandpaper disk from the surface of the sanding pad. The interface pad has a ring shape which corresponds in size to that of the sandpaper.

Description:
RELATED APPLICATION  
       [0001]    This application is related to application Ser. No. 60/354,028 filed Feb. 1, 2002 entitled DONUT SHAPED SANDING DISK now pending. 
     
    
     
       BACKGROUND  
         [0002]    Random orbital sanders act by moving the central axis of the sander in a circular motion as opposed to simply spinning a disk which is used for many rotary sanders such as the type one might attach to one&#39;s drill. Random orbital sanders frequently have a vacuum source attached to central portions of the pad to pull in dust and keep this from the surface being sanded. Even with a vacuum source there is a tendency for material to accumulate on the center portion of the pad which decreases pad life, reduces sanding efficiency and causes swirl marks on the sanded surface.  
         SUMMARY OF THE INVENTION  
         [0003]    The present invention is premised on the realization that one can improve the sanding efficiency of random orbital sanders by utilizing a donut shaped sandpaper disk, in other words, one which covers only the peripheral portion of the sanding pad. The central portion of the sander is preferably open to allow for accumulation of dust.  
           [0004]    Further, the present invention utilizes an annular interface pad along the outer peripheral portion of the random orbital sander. This interface pad attaches to the sanding pad. In turn, a sandpaper ring attaches to the interface pad. This structure extends sandpaper life and pad life, improves sanding efficiency and reduces swirl marks caused by the disk.  
           [0005]    The present invention will be further appreciated in light of the following detailed description and drawings in which: 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0006]    [0006]FIG. 1 is an exploded view of the present invention.  
         [0007]    [0007]FIG. 1A is an exploded view showing an alternate embodiment of the present invention.  
         [0008]    [0008]FIG. 2 is a bottom plan view of a sander.  
     
    
     DETAILED DESCRIPTION  
       [0009]    As shown in FIG. 1, there is a random orbital sander  11  which includes a circular pad surface  12 . The pad surface  12  includes a plurality of vacuum holes  14  designed to communicate with a vacuum source to remove dust during sanding. Generally the surface of the pad will have a hook-type plastic material similar to Velcro brand material which is adapted to engage a pile material.  
         [0010]    Attached to the surface  12  of the sanding pad  15  is an annular interface ring or pad  16 . The interface pad  16  has an inner  17  and outer  18  diameter. The inner diameter is large enough to expose the vacuum holes  14  in the pad  15 . The outer diameter  18  is about equal to or slightly larger than the outer diameter of the pad  15 .  
         [0011]    Generally this interface pad will have a thickness of from {fraction (1/16)}″ to ¾″ or more. Preferably it will be ⅛″ to ¾″ thick. This separates the plane of the sanding disk from the plane of the center of the sanding pad. The interface pad  16  can be made from a variety of materials but is preferably foam rubber. The durometer of the interface pad  16  can vary from 20 to 90 durometer depending on the desired sanding activity. Although less preferred, the interface pad can be part of the sanding pad or permanently attached to the sanding pad.  
         [0012]    The inner surface  21  of the interface pad  16  is a pile material which attaches to the hook material of the sanding pad surface  12 . The outer surface  22  of the interface pad in turn is a hook material.  
         [0013]    Attached to the interface pad is an annular sandpaper ring  24  which has an internal diameter 25 preferably about equal to the internal diameter of the interface pad and an exterior diameter 26 approximately equal to the external diameter of the interface pad. Likewise this sanding ring  24  has an inner surface  27  which is a pile material. It is adapted to firmly attach to the hook material of the interface pad  16  and of course its outer surface  28  is an abrasive material. The abrasive material can vary depending upon the desired sanding activity.  
         [0014]    In this application the hook and pile materials can be replaced with a pressure sensitive adhesive. But this is less preferred.  
         [0015]    The sanding disk is a sandpaper disk which is very flexible and adapted to bend when the interface pad bends.  
         [0016]    In operation the interface pad is attached to the pad of the random orbital sander. This leaves the vacuum holes exposed and leaves an open area in the inner portion of the interface pad. A sanding ring  24  would is attached to the pile surface of the interface pad  16  and the apparatus would be ready for sanding. Typically with a random orbital sander, the entire surface of the sanding disk is placed against the product being sanded. Thus, as dust is produced, it is sucked up through the vacuum holes and does not accumulate in the center portion of the disk.  
         [0017]    In the drawings, FIG. 1 and FIG. 2 depict a sanding ring  24  with a wavy edge. This facilitates sanding internal radiused surfaces. FIG. 1A shows a straight edge disk  24   a  to be used in attachment with a straight edge interface paid  16   a . Either can be used.  
         [0018]    The width of the sandpaper ring, i.e., the difference between ID and OD is usually about one-sixth to one-half and preferably about one-third the size of the OD. But this can vary as long as vacuum holes in the sanding disk are exposed and sufficient sandpaper is provided to effectively sand a surface. An inch to an inch and a half for a 6″ disk is adequate.  
         [0019]    Utilization of the sanding disk of the present invention along with the interface pad has a number of different advantages. Since one changes the interface pad, one can vary the thickness depending upon the desired operation. This also increases the life of the sandpaper or sanding disk and avoids forming swirls on the sanded surface which are caused by dust accumulated in the center portion of a standard disk.  
         [0020]    Further, the interface pad is relatively inexpensive compared to the pad of the sander. Since the sandpaper is placed on and removed from the interface pad as opposed to the sanding disk, wear on the sanding disk is reduced. The interface pad can be cheaply and easily replaced whereas the sanding disk would be much more expensive. Further because one can easily change the interface pad, one can change the softness or hardness of the pad depending on desired application without the need to change sanders or the pad on the sander.  
         [0021]    Particularly with an external radius surface, this significantly improves sanding efficiency. Since many different hole patterns are used for different sanders requiring stocking different materials, the present invention eliminates this concern.  
         [0022]    This also increases the efficacy of the vacuum, reduces sanding time and improves the efficiency of the sanding surface.  
         [0023]    In an alternate embodiment of the present invention instead of using an interface pad, one could modify the sanding pad of the sander wherein the central portion is removed or milled out providing a flat or concave, indented area. However, this is less preferred as it does not have all of the advantages of using the interface pad.  
         [0024]    This has been a brief description of the present invention along with the preferred method of practicing the present invention.