Abstract:
A blade sharpening apparatus comprising a rotor, including a plurality of interleaved fingers, operative to interface with the cutting edge of a blade. The rotor is coupled to a rotary drive, such as an electric motor, thereby automating the sharpening process. Preferably, each of the fingers is flexible and includes a lead-in in the form of a radius or chamfer to prevent kick back from the heel of the blade or knife being sharpened. It is also preferable that the sharpening fingers include a portion of abrasive material or surface treatment.

Description:
BACKGROUND 
       [0001]    Traditionally, knives such as butcher&#39;s knives and chefs knives were sharpened or honed using a honing steel and/or whetstone. However, as many people did not have the necessary skill to use such steels to produce good cutting edges on their knives, many different types of knife sharpeners have been developed over the years. While these knife sharpeners are easier to use for the average person, they generally have one or more practical limitations and so there is still a quest to develop an improved knife sharpener. Accordingly, there is a need for a knife sharpener that replicates the honing action of a traditional chef/butcher steel, but with more speed, efficiency and accuracy. 
       SUMMARY 
       [0002]    Provided herein is a blade sharpening apparatus comprising a rotor, including a plurality of interleaved fingers, operative to interface with the cutting edge of a blade. The rotor is coupled to a rotary drive, such as an electric motor, thereby automating the sharpening process. Preferably, each of the fingers is flexible and includes a lead-in in the form of a radius or chamfer to prevent kick back from the heel of the blade or knife being sharpened. It is also preferable that the sharpening fingers include a portion of abrasive material or surface treatment. 
         [0003]    The rotor may be formed of a unitary casting or stamping or may be an assembly including first and second rotors. Each rotor could include a hub with a plurality of fingers extending radially therefrom. Each of the rotors is disposed about a rotor shaft such that respective fingers of the first and second rotors are interleaved with one another. 
         [0004]    The foregoing and other features, utilities, and advantages of the invention will be apparent from the following more particular description of the embodiment of the invention as illustrated in the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0005]    The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate an embodiment of the present invention and together with the description, serve to explain the principles thereof. Like items in the drawings are referred to using the same numerical reference. 
           [0006]      FIG. 1  is a top plan view of the blade sharpening apparatus according to the exemplary embodiment shown here with a transparent housing in order to illustrate selected internal components; 
           [0007]      FIG. 2  is a side view in elevation of the blade sharpening apparatus shown in  FIG. 1 ; 
           [0008]      FIG. 3  is a front view in elevation of the blade sharpening apparatus shown in  FIGS. 1 and 2 ; 
           [0009]      FIG. 4  is a perspective view of a representative rotor assembly interfacing with the cutting edge of a knife; 
           [0010]      FIG. 5  is a perspective view of the rotor assembly shown in  FIGS. 1-3 ; 
           [0011]      FIG. 6  is a front view in elevation of the rotor assembly shown in  FIG. 5 ; 
           [0012]      FIG. 7  is a top plan view of the rotor assembly shown in  FIGS. 5-6 ; 
           [0013]      FIG. 8  is a front view in elevation of a preferred sharpening finger construction; 
           [0014]      FIG. 9  is a cross-sectional view of a sharpening finger taken about line  9 - 9  of  FIG. 8 ; 
           [0015]      FIG. 10  is a perspective view of the rotor assembly shown in  FIG. 4 ; 
           [0016]      FIG. 11  is a front view in elevation of the rotor assembly shown in  FIGS. 4 and 10 ; 
           [0017]      FIG. 12  is a top plan view of the rotor assembly shown in  FIGS. 4 ,  10 - 11 ; 
           [0018]      FIG. 13  is a perspective view showing another alternative construction of a rotor assembly; 
           [0019]      FIG. 14  is a front view in elevation of the rotor assembly shown in  FIG. 13 ; and 
           [0020]      FIG. 15  is a top plan view of the rotor assembly shown in  FIGS. 13 and 14 . 
       
    
    
     DETAILED DESCRIPTION 
       [0021]    The technology of the present application will be explained with reference to the figures. While the knife sharpener is explained with particular reference to certain devices and materials, it should be understood that those devices and materials are exemplary in nature and should not be construed as limiting. 
         [0022]    The disclosed blade sharpening apparatus replicates the honing action of a traditional chef/butcher steel, but with more speed, efficiency and accuracy. The sharpening angles are set by intersecting fingers, eliminating human error that has plagued the traditional manual Steel for many years. The present invention relates to a knife blade sharpener that utilizes overlapping, resiliently flexible fingers or strips, as disclosed in U.S. Pat. No. 6,769,327, which is hereby incorporated by reference in its entirety. 
         [0023]    Illustrated in  FIG. 1 , blade sharpening apparatus  10  includes a housing  12 , which supports a rotary drive, such as electric motor  16 . Motor  16  is coupled to rotor assembly  20  via shaft  25 . The sharpener is powered via cord  14  that may be plugged into a standard wall outlet as is well known in the art. Motor  16  is controlled with buttons  18 ( 1 ) and  18 ( 2 ). These buttons are momentary switches that while depressed cause the motor to rotate either clockwise or counterclockwise depending on which button is depressed. When operated by the users left-hand, for instance, the user&#39;s thumb would operate momentary switch  18 ( 1 ) causing the rotor to rotate clockwise as viewed from the front. Conversely if the user is operating sharpener  10  with their right hand then the user would depress momentary switch  18 ( 2 ) causing the rotor to rotate counter clockwise. Guards  17 ( 1 ) and  17 ( 2 ) inhibit the user from depressing the switches with their forefinger and helps protect their thumb. In this way, the sharpener is designed to safely pull the knife away from the user. 
         [0024]    Rotor assembly  20  is disposed on shaft  25  and includes first rotor  30 ( 1 ) and second rotor  30 ( 2 ) interleaved with each other. Each rotor includes fingers  34 ( 1 ) and  34 ( 2 ) respectively. Opposed inwardly facing surfaces of these fingers interface with the blade being sharpened. Rotor assembly  20  rotates within housing  12 , which includes slot  13  exposing a portion of rotor assembly  20 . Thus, with further reference to  FIG. 4 , a knife blade  1  may be inserted into slot  13  as rotor assembly  20  is rotating, thereby sharpening the blade. Also shown in  FIG. 4  is an alternative construction of the rotor assembly  120 . In this perspective view it can be seen how inwardly facing opposed surfaces of the rotor assembly interface with the blade of knife  5 . In order to sharpen blade  1  of knife  5  a user grasps handle  3  and inserts blade  1  through slot  13  of housing  12  in order to access the rotor assembly. Rotor assembly  120  rotates in either direction “R” depending on which button is depressed thereby automating the sharpening process. The user grasps handle  3  of knife  5  and translates the knife within slot  13  back-and-forth along direction “X” thereby sharpening the entire length of the blade. 
         [0025]      FIG. 5  is a perspective view of rotor assembly  20  shown in more detail. It may be better appreciated here that rotors  30 ( 1 ) and  30 ( 2 ) are preferably of the same construction. Thus, each rotor includes a plurality of fingers  34 . As perhaps best shown in  FIG. 7 , respective fingers  34 ( 1 ) and  34 ( 2 ) of rotors  30 ( 1 ) and  30 ( 2 ) are interleaved with each other creating an included angle “a” operative to interface with the blade to be sharpened. The fingers may form any included angle, or variable angles. The included angle may either stay constant as a knife is pressed down and the fingers flex, or the angle may change. The various arrangements illustrated in the figures may include any number and/or shape of fingers. The fingers can be made of any material, with any abrasive coating or smooth surface, or non-coated material, or mixture of surfaces on the fingers. Preferably, the fingers are at least partially covered with 500 grit industrial diamond coating. 
         [0026]      FIG. 8  illustrates a rotor assembly similar to that shown in  FIG. 6  with an alternate preferred construction of the sharpening finger  34 ( 2 ). In this case the sharpening finger includes a pair of lead-ins. As can be seen in  FIG. 9  these lead-ins  40  are in the form of a radius. It is important to note that the radius does not extend all the way to the root  44  of the fingers. This construction allows fingers  34  to remain flexible. 
         [0027]      FIGS. 10-12  illustrate an alternative construction of rotor assembly  120  introduced in  FIG. 4 . This construction is similar to that shown and described with respect to  FIGS. 5-7 . In this case however each finger is narrowed providing an open space between the interleaved fingers.  FIGS. 13-15  illustrate yet another alternate construction for rotor assembly  220 . In this case, each finger  234  has a spiral construction such that fingers  234  extend radially from their respective hub  235  along an arcuate path. 
         [0028]    It should be understood that while the rotor has been described as an assembly, it is contemplated that the rotor could also be formed of a single unitary construction. Such construction could be a casting or stamping formed from sheet-metal. The rotors are preferably formed of a metallic material such as aluminum or steel but could be formed of a suitable plastic material as well. Each finger may include an abrasive material impregnated into the surface or bonded to the surface of each finger. Alternatively the surface of each finger could be disrupted such as by crosshatching as a means to provide an abrasive surface to aid in sharpening the blade. 
         [0029]    Accordingly, the present invention has been described with some degree of particularity directed to the exemplary embodiments. It should be appreciated, though, that the present invention is defined by the following claims construed in light of the prior art so that modifications or changes may be made to the exemplary embodiments without departing from the inventive concepts contained herein.