Abstract:
A hand-held sharpening device for sharpening a blade including an elongated sharpening polygon having a plurality of substantially planar sharpening surfaces for receiving the edge of a blade, opposite ends on the elongated sharpening polygon, a plastic cap covering each of the ends, a graspable extension extending outwardly from one of the caps, and a tie in the form of a chain secured to the graspable extension.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This is a continuation of application Ser. No. 09/069,583 filed Apr. 29, 1998 
    
    
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     Not Applicable 
     BACKGROUND OF THE INVENTION 
     The present invention relates to a hand-held portable sharpener which can be carried in the pocket or suspended from a part of a person&#39;s clothing by means of a suitable tie, such as a chain. 
     By way of background, hand-held portable sharpeners having a cylindrical sharpening stone and end caps are known. However, devices of this type, when used, permit the knife to rotate circumferentially about the cylindrical surface whereby a constant sharpening angle of a knife blade relative to the stone cannot be maintained. 
     BRIEF SUMMARY OF THE INVENTION 
     It is one object of the present invention to provide an improved portable hand-held blade sharpener in the form of a polygon having a plurality of substantially planar sharpening surfaces against each of which a constant sharpening angle may be maintained. 
     Another object of the present invention is to provide an improved hand-held portable sharpening device in the form of an elongated polygon wherein the straight edges and vertices at its opposite ends are protected against chipping or nicking by plastic end caps. 
     A further object of the present invention is to provide an improved hand-held portable sharpener which can be conveniently grasped at one end thereof during a knife sharpening operation. Other objects and attendant advantages of the present invention will readily be perceived hereafter. 
     The present invention relates to a hand-held sharpening device for sharpening a blade comprising an elongated sharpening polygon having a plurality of elongated substantially planar sharpening surfaces for receiving the edge of a blade, an end portion on said elongated sharpening polygon, a plurality of straight edges on said end portion, and a cap covering said straight edges and extending onto said end portion of said polygon. 
     The various aspects of the present invention will be more fully understood when the following portions of the specification are read in conjunction with the accompanying drawings wherein: 
    
    
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING 
     FIG. 1 is a side elevational view of the hand-held blade sharpening device of the present invention; 
     FIG. 2 is a side elevational view of the device rotated 120° to the left from its position of FIG. 1; 
     FIG. 3 is a side elevational view of the device rotated 120° to the left from its position of FIG. 2; 
     FIG. 4 is an enlarged cross sectional view taken substantially along line  4 — 4  of FIG. 1; 
     FIG. 5 is an enlarged view taken substantially in the direction of arrow  5 — 5  of FIG.  1  and showing the straight edges and the vertices at the end of the elongated sharpening polygon; 
     FIG. 6 is a view similar to FIG. 5 but showing the manner in which the straight edges and vertices can be nicked by contact with hard objects in the event they are not protected by a cap; 
     FIG. 7 is an enlarged fragmentary side elevational view taken substantially in the direction of arrows  7 — 7  of FIG. 6; 
     FIG. 8 is an enlarged fragmentary side elevational view taken substantially in the direction of arrows  8 — 8  of FIG. 6; and 
     FIG. 9 is an enlarged fragmentary side elevational view taken substantially in the direction of arrows  9 — 9  of FIG.  3  and showing the manner in which an edge of the sharpening polygon may be chipped. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The hand-held sharpening device  10  includes a sharpening polygon  11  of suitable ceramic material having three substantially planar sharpening surfaces  12 ,  13  and  14 , the cross section of which constitutes an equilateral triangle, as can be seen from FIG.  4 . Face  12  includes a groove  15  for sharpening points of objects, such as fish hooks. It will be appreciated that other polygonal shapes having substantially planar sharpening surfaces can be used. 
     Sharpening polygon  11  terminates at straight edges  17 ,  19  and  20  (FIG. 5) at its upper end, and it terminates at corresponding straight edges  17 ′,  19 ′ and  20 ′ at its lower edges. Straight end  17 ,  19  and  37  meet at a vertex  21 ; straight edges  19 ,  20  and  39  meet at a vertex  22 ; and straight edges  20 ,  17  and  40  meet at a vertex  23 . At the opposite end of sharpening polygon  11 , straight edges  17 ′,  19 ′ and  37  meet at a vertex  21 ′; straight edges  19 ′,  20 ′ and  39  meet at a vertex  22 ′; and straight edges  20 ′,  17 ′ and  40  meet at a vertex  23 ′. 
     The sharpening polygon  11  taken by itself without end caps  30  and  31  thereon is approximately  4  inches long. When the sharpening polygon  11  is unprotected without the end caps  30  and  31 , its straight edges, such as  17 ,  19  and  20 , (FIG. 6) may be chipped at  26 ,  27  and  29 , respectively, and also the vertices  21 ,  22  and  23  may also be chipped at  32 ,  33  and  34 , respectively, as shown in FIG. 6, because the ceramic material of which polygon  11  is made is frangible and extremely susceptible of chipping. Analogous chipping can occur at the analogous edges and vertices at the opposite end  24 ′ of the sharpening polygon. The sharpening polygon  11 , by itself, without end caps  30  and  31  thereon, if carried in a person&#39;s pocket, will cause undue wear as the vertices  21 ,  22  and  23  dig into the pockets, and this is especially pronounced when the vertices are jagged due to chipping as shown at  32 ,  33  and  34  and at the corresponding vertices at the opposite end. Also, the nicked or jagged portions, such as  26 ,  27  and  29 , essentially act as serrated edges which not only can wear out a pocket but also can abrade the user&#39;s hand. Under extreme conditions the ceramic can fracture and become a true razor-like edge which would be extremely sharp and dangerous. 
     In order to remedy the foregoing, molded plastic end caps  30  and  31  are mounted onto the end portions  24  and  24 ′, respectively, to thereby protect the straight edges and the vertices at which the various straight edges meet. As can be seen from FIG. 2, end cap  30  includes a cavity  34  which fits in complementary mating relationship over end  24 . Also, cap  31  includes a cavity  34 ′ which receives polygon end  24 ′ in complementary mating relationship. Caps  30  and  31  not only protect the edges and vertices which they cover from chipping, but they also tend to cushion the polygon  11  against fracture in the event it is dropped on a hard surface. The fracture can readily occur because the ceramic material is in the nature of glass which shatters easily. Also, since end caps  30  and  31  are mounted on the ends of the ceramic member, there is a high probability that its longitudinal edges  37 ,  39  and  40  will not contact a hard surface such that a chipped edge, such as  41 , will be produced. If the latter occurs, the surfaces  12  and  14  adjacent edge  40  will be rendered useless for sharpening, as it is necessary that such edges should remain straight for a proper sharpening operation. 
     The hand-held sharpener  10  may conveniently be held at one end for sharpening. In this respect, a graspable extension  41  is molded integrally with end cap  30  and extends outwardly therefrom about ¾ of an inch. This graspale extension may be held between the thumb and forefinger. Alternatively, the end cap  30  or the end cap  31  may also be held between the thumb and the forefinger with the thumb resting on a relatively flat surface such as  42  (FIGS. 1 and 4) and the vertex  43  of the cap opposite to surface  42  resting at the first joint of the forefinger. Surfaces  46  and  48  are flat surfaces which are analogous to flat surface  42 . Surfaces  42 ,  46  and  48  of cap  30  are essentially mirror images of surfaces  42 ′,  46 ′ and  48 ′, respectively, of cap  31  (FIG.  4 ). Alternatively, an end cap, such as  30 , can be held with the thumb on one flat surface thereof, the tip of the forefinger on another flat surface, and the side of the middle finger on the third flat surface. 
     A hole  44  extends through graspable extension  41  and a tie  45 , in the form of a chain, extends through hole  44 . The chain can be used to suspend sharpener  10  from any suitable object, such as clothing or a brief case, for ready access. Additionally, the chain may be used as an adjunct to graspable extension  41  for stabilizing the sharpening  10  when it is held at one end. In this respect, the chain would lie within the grasp of the second joints of the middle, fourth and little fingers while the thumb and forefinger bear on the cap itself. 
     It can thus be seen that the improved hand-held sharpener of the present invention is manifestly capable of achieving the above enumerated objects, and while a preferred embodiment of the present invention has been disclosed, it will be appreciated that it is not limited thereto but may be otherwise embodied within the scope of the following claims.