Abstract:
An electric sharpener having a pair of abrasive wheel assemblies including energy absorbing hubs mounted a powered drive shaft and further integral flexible radially extending arms affixed to respective outer abrasive rings. A pair of disk abrasives assemblies are also affixed to the powered rotatable shaft and include a pair of flexible metal disks operatively connected to a hub attached to the rotatable shaft.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    This invention relates to abrasive sharpeners, and more particularly, to an electric abrasive sharpener having adaptable flexible abrasive assemblies to prevent slowing abrasive speed and even stall of the motor during sharpening and provide a wide range of cutting capabilities. 
         [0003]    2. Summary of the Prior Art 
         [0004]    Numerous self-powered, electric abrasive sharpeners have been developed in the past. Although some past designs produce satisfactory results, the self-powered systems in the prior art are relatively expensive and must rely on the use of numerous precise components for maintain the abrasive element speed to satisfactorily sharpen tools. One convenient and advantageous feature not found in known sharpeners is to provide an economical and effective technique allowing the abrasive cutting element assembly to adapt to the tools being sharpened. Further, in the past the user of a sharpening would experience run-out or slowing of the abrasive elements, due to tools to be sharpened of different sizes, shapes, and amounts of force applied by the tool. Such run-out will, for example, decrease the quality of the sharpened edge of the tool by producing uneven cutting of the tool edge. 
       SUMMARY OF THE INVENTION 
       [0005]    It is therefore an objective of the invention to provide an improved electric sharpener for knives, scissors, and other implements having a flexible adaptable abrasive assembly for a power sharpener for preventing the abrasive assembly from slowing down during sharpening, the effect of which may produce uneven sharpening results or even stalling of the motor. During sharpening the flexible assembly of the invention absorbs forces applied to the abrasive surface such that a detrimental slowdown of the speed of the sharpener is alleviated. This results in an improved sharpening operation in which there is no significant slowing or altogether stopping of the rotation of the abrasive cutting elements due to their shape, size, or the force applied to the abrasive surface, conditions which previously in the prior art interfered with the quality of sharpening of a tool. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0006]      FIG. 1  is a front elevational view of the electric sharpener of the invention; 
           [0007]      FIG. 2  is a front elevational view, with parts removed, of the electric sharpener of  FIG. 1 ; 
           [0008]      FIG. 3  is a partial side perspective view, with parts removed, of the electric abrasive sharpener of  FIG. 1 ; 
           [0009]      FIG. 4  is a view of the electric abrasive sharpener of  FIG. 1 ; 
           [0010]      FIG. 5  is an end sectional view, taken along lines  5 - 5  of  FIG. 2 ; 
           [0011]      FIG. 6  is  FIG. 5  is an end sectional view, taken along lines  6 - 6 , of  FIG. 2 ; 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0012]    Referring now to  FIGS. 1-6 , there is illustrated a self-powered sharpener  2  having a housing  4 . A top portion  6  of housing  4  forms a curved enclosure having a first pair of curvilinear slots  10  and a second pair of curvilinear slots  12  which form two respective pairs of adjacent sharpening slots for receiving a variety of implements, such as, for example, knives, scissors, and other tools having edges to be sharpened. As seen in  FIGS. 2 and 3 , the slots  10  are defined by downward, generally opposed guide surface  10   a,    10   b  integrally formed on housing top portion  6 . Similarly the slots  12  are defined by downward, generally opposed guide surface  12   a,    12   b  integrally formed on housing top portion  6 . The guide surfaces  10   a,b  and  12   a,b  function to properly align the tool being sharpened adjacent abrasive assemblies to be described. 
         [0013]    As best seen in  FIGS. 2 ,  3  and  5 , a drive shaft  20  is mounted on suitable bushings within the housing  4  for rotation powered by a conventional electric motor  22  through belt connection  24 . A pair of abrasive wheel assemblies  30  are rotated by electric motor  22  and are positioned in respective operative alignment with slots  10 . The wheel assemblies  30  are mounted on a flexible center hub  32  which is affixed to drive shaft  20 . The flexible hub  32  further includes a radially extending center portion  34  comprising a plurality of flexible radial arms  34   a,  such as five in number as shown in  FIGS. 2 and 3 , that support an outer circumferentially extending, rigid abrasive ring  36 . The ring  36  forms a chamfer  38  having a raised continuous rib  40  extending around the shaft, and a suitable abrasive material affixed to rib  40  and chamfer  38 . The flexible hub  32  and arms  34   a  can comprise a flexible material, such as ceramic, plastic and other materials that can provide a spring-like energy absorbing properties. The mounting of the wheel assemblies  30  allow the abrasive surface to flex longitudinally relative to the shaft  20  and to rotationally absorb forces exerted by the tool on the abrasive by the user, These forces exerted by the tool being sharpened are not significantly transmitted through the abrasive wheel assemblies  30  to the drive shaft  20  to cause stall of the drive motor and any resulting significant reduction of the speed of the ring  34  to insure optimum sharpening results. The edge of a as a tool being sharpened is positioned in a selective one of slots in contact with the abrasive surfaces formed on abrasive wheel assemblies  30  in angled relationship as defined by sloped guide surfaces  10   a , 10   b.    
         [0014]    Referring now to  FIGS. 2 ,  3  and  5 , there is illustrated a second pair of abrasive cutting assemblies  50  using a pair of flat coated abrasive disks  52  which may be formed, for example, by a thin metal and the like and have a coating of an abrasive on their faces and the like for sharpening at the edge of a tool. The flexible flat disk  52  are each affixed on a drive shaft  20  in separated position in attachment to a flexible hub  54 , and are also rotated by drive motor  22 . The flat coated abrasive disks  52  are aligned with slots  12  to allow the user to guide tools having edges to be sharpened in the correct orientation to abrade the cutting edge against the abrasive flexible flat disks  52 . The abrasive disk assemblies  50  function similar to the previously described wheel assemblies  30  by being resiliently deflectable and angularly absorb the forces applied to the abrasive surface by the user during the sharpening operation so that stall of the drive motor prevented and the rotational speed of the abrasive surface is generally maintained for superior results in response to a large range of forces applied by the tool to a respective sharpening disk  52  during sharpening. The pair of wheel assemblies  30  using a flexible center hub  32  and abrasive outer ring  36 , and the pair of abrasive cutting surface assemblies  50  using flat coated abrasive disks  52  can be used in tandem or independently