Patent Publication Number: US-8113923-B2

Title: Chamfering tool and drum sander

Description:
RELATED APPLICATIONS 
     This application claims priority from provisional application No. 61/206,874 filed on Feb. 5, 2009. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to a tool for chamfering and sanding objects that require rounding, bevelling or sanding including but not limited to wood, metal and plastic. 
     BACKGROUND OF THE INVENTION 
     Various objects such as metal and plastic tools, furniture, wood dowels and pipes, require shaping, smoothing and finishing as they are assembled. The present invention provides a convenient tool that can be used for chamfering and sanding in a drill press or a three-jaw chuck. 
     SUMMARY OF THE PRESENT INVENTION 
     In an aspect of the present invention, a device for chamfering and sanding comprises: a cylindrical body having an open circular top and a closed bottom with the cylindrical body having a hollow conical interior, the conical interior defining an interior surface, and with the conical interior also defining an outside diameter and an inside diameter, wherein a difference between the outside diameter and inside diameter defines a sidewall; a shaft attached to the bottom of the cylindrical body; a first longitudinal slot in the side wall; and a second longitudinal slot in the sidewall. 
     These and other features, aspects and advantages of the present invention will become better understood with reference to the following drawings, description and claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a cross sectional side view of the device according to an embodiment of the present invention; 
         FIG. 2  is a bottom top view of the device according to an embodiment of the present invention; 
         FIG. 3  is a top view of the device according to an embodiment of the present invention; 
         FIG. 4  is a cross sectional side view of the device in a use configuration according to an embodiment of the present invention; 
         FIG. 5  is a top view of the device in a use configuration according to an embodiment of the present invention; and 
         FIG. 6  is a bottom top view of the device containing an abrasive sheet according to an embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE DRAWINGS 
     In an embodiment of the present invention, a tool for chamfering and sanding comprises a cylindrical body about 2.00 inches long, having a circular open top and a round shaped closed bottom. The cylindrical body contains a hollow cone. The circular open top has an inside diameter of about 1.25 inches and an outside diameter of about 1.5 inches resulting in a wall thickness at the open top edge of about 0.125″. The hollow cone starts at the open top and is disposed inside the cylinder to a depth of about 1.375 inches in a manner that the angle between the cone center line and the cone side walls ranges from about 22 degrees to about 24 degrees. The cone centerline is defined here as the line spanning from the tip of the cone and crossing the center of the circular open top. The preferred material for the device is plastic; however metal and wood also fall within the scope of the present invention. 
     A cylindrical shaft having a diameter of about 0.375 inches and a length of about 1.5 inches is threaded through the center of the round shape closed bottom to a depth of about 0.5 inches, stopping short of the tip of the hollow cone. The sidewall of the hollow cone contains two longitudinal slots about 0.078 inches wide that cut across the cone and the cylindrical body. As such, the width of each longitudinal slot varies across the length of the cylindrical body increasing in width as it moves toward the bottom. In an embodiment of the present invention, the two slots are diametrically opposed to each other. The hollow cone surface is lined with an abrasive paper, most typically 60 or 80-grit sandpaper. The sandpaper may be attached to the hollow cone surface using a pressure sensitive adhesive coated onto the backside of the sandpaper sheet. To further help keep the sandpaper in place, a corner of the sandpaper is pulled through each slot. For this purpose, a size 2.25″ wide and 3.25″ long sandpaper strip with pressure sensitive backing folded in half may be pressed into the cone in a way that the corners are tucked into the slot for a stronger hold. Any excess sandpaper protruding outside the cylinder surface is trimmed off. In an embodiment of the present invention a sandpaper sleeve is slipped onto the outside surface of the cylinder. The sleeve may have a diameter of about 1.5 inches and a length of about 1.5 inches. Adhesive may be used to attach the sleeve to the cylinder surface. The sandpaper on the sleeve may have a 60 or 80-grit and may be used for sanding the surfaces of the objects that have been previously chamfered or the surfaces of the objects that require smoothing. 
     The shaft of the device may be placed in a drill press or a three jaw chuck and rotated at variable speeds. The object requiring bevelling and/or sanding is inserted into the cone and pressed against the sandpaper as the sandpaper rotates with the device. Examples include the cut end of a wood dowel, a pipe and a rod. The device  10  is depicted in  FIGS. 1-5 . Shown are the cylindrical body  11  and the hollow cone  12  contained inside the cylindrical body  11 . A shaft  17  is attached to the closed bottom  14 . The side wall of the hollow cone comprises two slots  15 A and  15 B through which the sandpaper  16  is inserted for a stronger hold.  FIG. 4  shows an object  19  being chamfered inside the hollow cone  12 .  FIG. 6  shows the sandpaper sleeve  18  wrapped onto the outside surface of the cylinder. After the object  19  is chamfered, it may be placed against the sandpaper sleeve  18  for sanding and smoothing.