Knife Sharpener

Abstract

A knife sharpener comprises a base, a motor, a grinding wheel assembly, a rotary shaft and two springs. The working channel between the edge of the grinding disc and the grinding awl is automatically adjustable to accommodate different blade of different thickness. When the knife sharpener performs grinding operation, the grinding wheel assembly can simultaneously grind both cutting sides of the knife. In addition, the knife can be clamped firmly through the three contacting areas of the grinding disc, the grinding awl, and the cutting edge, so that the operation of knife grinding can be successfully performed.

1 . A knife sharpener capable of sharpening a cutting edge of a knife, the cutting edge of the knife including a first side and a second side, the knife sharpener comprising:
 a base defined with a receiving space for installation of grinding assemblies, a plurality of slots connecting with the receiving space being defined in a top surface of the base;   a motor serving as a power source of the knife sharpener being assembled at one side of the receiving space;   at least one grinding wheel assembly including two assembling members, a grinding disc and a grinding awl, each assembling member being provided with a bearing, the two assembling members being distantly disposed in the receiving space, so that the grinding disc is located between the two assembling members, the grinding disc has two surfaces, one of which is an annular-shaped grinding surface for grinding the cutting edge, and a through hole formed in the middle of the grinding disc, the grinding awl being located between the two assembling members in such a manner that one surface of the grinding awl abuts against the grinding surface of the grinding disc, another surface of the grinding awl is rested against a fixing member, a surface of the grinding awl facing the grinding surface is a tapered grinding surface with a taper angle of 9-45 degrees, which serves as another grinding surface of the knife sharper, a through hole formed in the middle of the grinding awl, the grinding disc and the edge of the grinding awl being located in a certain distance away from each other to form a working channel to be aligned with one of the slots;   a rotary shaft having one end fixed to a rotor of the motor, so that it is rotated by the motor, another end of the rotary shaft in turn passing through the bearing of the assembling member, the through hole of the grinding awl, the through hole of the grinding disc and the bearing of another assembling member, so that the two bearings and the grinding awl are fixed on the rotary shaft, that the grinding disc is moveable along the rotary shaft, and the rotary shaft is able to rotate the grinding disc and the grinding awl to grind the knife;   two springs, one spring having one end biased against the grinding disc, another spring having one end biased against the grinding awl, so as to keep the grinding surface of the grinding disc and the tapered grinding surface of the grinding awl close to each other under normal conditions, when the cutting edge of a knife is being ground in the working channel, the first side of the cutting edge being in contact with the annular-shaped grinding surface at two contacting areas, while the second side of the cutting edge being in contact with the tapered grind surface at one contacting area, the cutting edge can move the grinding disc to make the grinding surface and the tapered grinding surface move slightly in horizontal direction, while the tapered grinding surface can keep the cutting edge from overly moving downwards, so that the annular-shaped grinding surface and the tapered grinding surface can properly contact the cutting edge.   
   
   
       2 . The knife sharpener as claimed in  claim 1 , wherein three restricting ribs are distantly mounted in an inner surface of the receiving space, while three engaging grooves are formed in an edge of the assembling members and three engaging grooves are formed on an outer surface of a housing of the motor to mate with the restricting ribs, so that the assembling members and the motor are stably assembled in the receiving space. 
   
   
       3 . The knife sharpener as claimed in  claim 1 , wherein a receiving concave is defined in the annular-shaped grinding surface of the grinding disc, and iron chips produced during the course of grinding will fall into the receiving concave. 
   
   
       4 . The knife sharpener as claimed in  claim 1 , wherein the rotary shaft is hexagonal-shaped, and the through hole of the grinding disc is a hexagonal hole accordingly, so that the rotary shaft is able to rotate the grinding disc and the grinding awl to grind the knife. 
   
   
       5 . The knife sharpener as claimed in  claim 1 , wherein a magnet is defined in the base for attracting iron chips and preventing the iron chips from flying in all directions, and a user can easily take out the magnet to clean out the iron chips.