Description AUTO KNIFE SHARPENER

Technical Field

[1] The present invention relates to an automatic knife sharpener, and more particularly, to an automatic knife sharpener, in which two elastic grinding discs in stead of a grinding stone or a grinding bar are opposed to each other and partially pressurized to thereby enhance a degree of contact of a knife blade, and which can decompose oil stained on the surface of the blade using water and a cleaning material at the same time with grinding of the blade. Background Art

[2] In general, when a knife blade gets blunt at home or in a restaurant, a user rotates a grinding stone at high speed using a motor and grinds the knife blade manually while contacting the knife blade with the grinding stone to thereby sharpen the knife blade,.

[3] Alternatively, the user grinds the knife blade manually without using the motor while contacting a grinding bar or a grinding whetstone, which has fine groove on the surface thereof, with the knife blade.

[4] However, since the grinding stone or the grinding bar is made of solid materials and the knife blade is also made of a solid material, only the edged portion of the knife blade in contact with the grinding stone or the grinding bar is grinded, and so, an angle of the knife blade gets blunt over time. So, such conventional methods for grinding the knife blade have several problems in that the performance of the knife is deteriorated over time since the knife blade cannot be returned to its original sharp state, and in that the user has to frequently grind the knife blade since the knife blade which is grinded at only its edged portion is easily worn.

[5] In addition, the conventional methods for grinding the knife blade have another problem in that a size of equipment is increased or the unit costs of the product and components are increased since the grinding stone or the grinding bar is heavy and the manufacturing method is very complicated.

[6] Moreover, the conventional methods for grinding the knife blade have additional several problems in that oil stained on the grinding stone or the grinding bar interrupts grinding, in that it takes much time to grind the knife blade and the precision and sharpness of the knife blade are decreased since a grinding efficiency of the grinding stone or the grinding bar is deteriorated. Disclosure of Invention Technical Problem

[7] Accordingly, it is an object of the present invention to provide an automatic knife

sharpener, in which two grinding discs made of an elastic material are partially pressurized in the shape of "V", thereby always maintaining the performance of the knife blade in the optimal state since a grinding angle of the knife blade is sharp and a grinding area is large and maintaining the performance of the knife blade as it is even though the knife blade is not frequently grinded since an angle of the grinded blade is generally sharp.

[8] Another object of the present invention is to provide an automatic knife sharpener, in which grinding discs is light, is easy to manufacture and is convenient to replace, thereby realizing simplification and minimization of equipments and considerably reducing unit costs of the product and components.

[9] A further object of the present invention is to provide an automatic knife sharpener that water and a cleaning material can be used simultaneously to easily remove oil, thereby reducing a grinding period of time by promoting grinding and improving a grinding efficiency, and enhancing the precision and sharpness of a knife blade. Technical Solution

[10] To achieve the above objects, the present invention provides an automatic knife sharpener comprising: a rotary shaft; first and second rotating plates adapted to be rotated together with the rotary shaft; first and second grinding discs respectively mounted on the first and second rotating plates in a movable and loose-fitting way, the first and second grinding discs having a grinding material mounted on the surfaces thereof and being oppositely mounted to each other in such a way that the blade is inserted therebetween; and partially pressurizing means for pressurizing a side of the first grinding disc and a side of the second grinding disc such that the first grinding disc and the second grinding disc are rotated in a state where they engage with each other with the blade interposed between the first grinding disc and the second grinding disc.

[11] The rotary shaft can be rotated by mechanical or electric power, and in a preferred embodiment of the present invention, rotated by a motor, which is operated by electricity.

[12] In an aspect of the present invention, the present invention provides an automatic knife sharpener, which can grind a knife blade using a motor, comprising: a main body; a motor mounted on the main body and generating rotational driving power; a power supply for applying electric power to the motor; first and second rotating plates detachably mounted on the rotary shaft of the motor and rotating together with the rotary shaft; first and second grinding discs respectively mounted on the first and second rotating plates in a movable and loose-fitting way, the first and second grinding discs having a grinding material mounted on the surfaces thereof and being oppositely

mounted to each other in such a way that the blade is inserted therebetween; and partially pressurizing means for pressurizing a side of the first grinding disc and a side of the second grinding disc such that the first grinding disc and the second grinding disc are rotated in a state where they engage with each other in the shape of "V" when they are viewed from the top with the blade interposed between the first grinding disc and the second grinding disc.

[13] In addition, the first grinding disc and the second grinding disc respectively have hemispherical protrusions and the first rotating plate and the second rotating plate respectively have hemispherical grooves corresponding to the hemispherical protrusions, so that the first grinding disc and the second grinding disc are mounted on the first rotating plate and the second rotating plate in the movable and loose-fitting way.

[14] Moreover, the partially pressurizing means is freely rotatably mounted on a rotating member hinge-coupled by a hinge shaft mounted on the main body, and includes: a first pressure roller elastically pressurized in a direction of the first grinding disc by an elastic spring mounted between the main body and the rotating member; and a second pressure roller mounted on a cover of the main body for pressurizing the second grinding disc together with the first pressure roller when the cover of the main body is closed.

[15] Furthermore, the cover is hinge-coupled with the main body, a closed shield is mounted at a blade entrance, a locking device is mounted between the main body and the cover, a waterproof packing is mounted between the main body and the cover, and a waterway groove is formed on the external side of the blade entrance.

[16] Additionally, a blade supporter is mounted between the first grinding disc and the second grinding disc, the blade supporter being freely rotated.

[17] Moreover, the automatic knife sharpener according to the present invention further includes: a rotary safety switch connected to the power supply so as to be automatically operated when the blade is put therein and to automatically stop its operation when the blade is withdrawn therefrom, the rotary safety switch being hinge-coupled and horizontally mounted under the blade entrance; and an indirect safety switch hinge-coupled and vertically mounted at a side of the blade entrance of the main body so as to be manipulated with a user's hand.

[18] In another aspect of the present invention, the grinding disc includes a hole formed at the center thereof for allowing a rotary shaft to pass therethrough, a plurality of round protrusions formed on a side thereof so as to be fit to a rotating plate, and a grinding material formed on the other side thereof.

[19] Meanwhile, according to the present invention, the first grinding disc and the second grinding disc are constructed by adhering diamond grinding stone or sand paper to a thin elastic steel sheet.

[20] Detailed features and advantages of the present invention will be apparent from the following detailed description of the preferred embodiments of the invention in conjunction with the accompanying drawings.

Advantageous Effects

[21] As described above, the automatic knife sharpener according to the present invention can always keep the optimal state in performance of the knife blade since a grinding angle of the knife blade is sharp and a grinding area is large, and keep the performance of the knife blade as it is even though the knife blade is not frequently grinded since an angle of the grinded blade is generally sharp. In addition, the automatic knife sharpener can achieve simplification and minimization of an equipment and considerably reduce unit costs of the product and components since the grinding discs are light, easy to manufacture and convenient to replace. Moreover, the automatic knife sharpener can reduce a grinding period of time and enhance the precision and sharpness of the blade since water and a cleaning material can be used simultaneously to easily remove oil. Mode for the Invention

[22] First, as shown in FIGS. 1 to 4, according to a preferred embodiment of the present invention, an automatic knife sharpener includes: a main body 10, a motor 11, a power supply 12, a first rotating plate 13 and a second rotating plate 14, a first grinding disc

15 and a second grinding disc 16, a partially pressurizing device 17, a rotary safety switch 18, and an indirect safety switch 19.

[23] Here, a hinge-coupled cover 20 is mounted at a side of the main body 10, and serves as a case for covering and protecting the motor 11.

[24] In addition, the motor 11 is mounted on the main body 10 to generate turning power by receiving electric power from the power supply 12.

[25] Moreover, the power supply 12 supplies electric power to the motor 11 according to a user's manipulation of the rotary safety switch 18 and the indirect safety switch 19.

[26] Furthermore, the first rotating plate 13 and the second rotating plate 14 are detachably mounted on a rotary shaft 21 of the motor 11, and rotate together with the rotary shaft 21.

[27] Additionally, the first grinding disc 15 and the second grinding disc 16 are respectively mounted on the first rotating plate 13 and the second rotating plate 14 in a movable and loose-fitting way. The first grinding disc 15 and the second grinding disc

16 respectively have grinding materials disposed on the surfaces thereof, and are opposite to each other in such a way that a knife blade can be inserted therebetween.

[28] Here, the first grinding disc 15 and the second grinding disc 16 may be constructed in such a way that several pieces of sandpaper 23 are adhered on a thin elastic steel

sheet 22 as shown in FIGS. 7 and 8, or that a diamond grinding stone 24 is coated on the thin elastic steel sheet 22 as shown in FIGS. 9 and 10.

[29] Moreover, as shown in FIG. 11, to mount the first grinding disc 15 and the second grinding disc 16 on the first rotating plate 13 and the second rotating plate 14 in the movable and loose-fitting way, the first grinding disc 15 and the second grinding disc 16 respectively have a number of hemispherical protrusions 25, and the first rotating plate 13 and the second rotating plate 14 respectively have a number of hemispherical grooves 26 corresponding to the hemispherical protrusions 25.

[30] In addition, as shown in FIGS. 4 and 6, the partially pressurizing device 17 pressurize sides of the first grinding disc 15 and the second grinding disc 16 in such a way that the first grinding disc 15 and the second grinding disc 16 are rotated in a state where the blade 1 is located between the first grinding disc 15 and the second grinding disc 16 and the first grinding disc 15 and the second grinding disc 16 engage with each other in the shape of "V" when they are viewed from the top. Such a pressurizing device 17 includes a first pressure roller 171 shown in FIGS. 3 and 4 and a second pressure roller 172 shown in FIGS. 2 and 6.

[31] That is, as shown in FIG. 3 and 4, the first pressure roller 171 is rotatably mounted on a rotating member 28 hinge-coupled to the main body 10 via a hinge shaft 27 mounted on the main body 10, and elastically pressurized in a direction of the first grinding disc 15 by an elastic spring 29 mounted between the main body and the rotating member 28.

[32] Furthermore, as shown in FIG. 2, the second pressure roller 172 is mounted on the cover 20 of the main body 10, and so, pressurizes the second grinding disc 16 together with the first pressure roller 171 when the user closes the cover of the main body 10.

[33] Here, as shown in FIGS. 6 and 12, the first pressure roller 171 and the second pressure roller 172 are respectively engaged-rotated in contact with the first grinding disc 15 and the second grinding disc 16, and respectively have inclined faces 173 in such a way that they form an angle in the shape of "V", and elastic layers 175 formed on the external side of a metal rotary shaft 174 and a synthetic resin layer 176 and made of rubber, urethane, silicon or others.

[34] So, as shown in FIGS. 5 and 6, when the user closes the cover 20 of the main body

10, the first pressure roller 171 and the second pressure roller 172 partially pressurize only some portions of the first grinding disc 15 and the second grinding disc 16, so that the first grinding disc 15 and the second grinding disc 16 are elastically bent in the shape of "V" when they are viewed from the top, whereby contact areas of the first grinding disc 15 and second grinding disc 16 to the blade 1 are maximized to thereby cut the blade 1 generally sharply. In this instance, the hemispherical protrusions 25 of the first grinding disc 15 and second grinding disc 16 are coupled with the hemi-

spherical grooves 26 of the first rotating plate 13 and the second rotating plate 14 loosely to thereby transfer the turning power of the motor 11, and at the same time, can move from side to side to thereby keep the rotation of the"V"form between the first grinding disc 15 and the second grinding disc 16.

[35] In the meantime, as shown in FIGS. 2 and 4, a blade-shaped selection lever 30 for moving the first pressure roller 171 back and forth is mounted in such a way as to be caught by a multi-stage groove 31 mounted on the main body 10, and selectively pressurizes the first pressure roller 171 according to kinds of the blade, namely, a single-side blade or a double-side blade.

[36] Here, as shown in FIG. 3, a plate spring 39 may be mounted for pressurizing the first pressure roller 171 in a direction to move the first pressure roller 171 backwardly.

[37] Moreover, as shown in FIGS. 1 and 5, the cover 20 of the main body 10 is hinge- coupled with the main body 10, a closed shield 32 is mounted at a blade entrance 20a, and a locking device 33 is mounted between the main body 10 and the cover 20. A waterproof packing 34 is mounted between the main body 10 and the cover 20 as shown in FIG. 2, and a waterway groove 35 may be formed on the external side of the blade entrance 20a as shown in FIG. 13.

[38] When the lower end portion of the cover is filled with cleaning water in such a way that the discs are partially submerged, fat can be removed from the blade at the same time with grinding of the blade. So, when the blade 1 is grinded, even though water and cleaning material are put into the knife sharpener together, since water and cleaning material do not spatter to the user or flow to the outside, the knife sharpener can cleanly grind the blade and cleanly remove the fat, which interrupts grinding, during grinding.

[39] Meanwhile, as shown in FIGS. 6 and 14, it is preferable that a freely rotating blade supporter 36 is mounted between the first grinding disc 15 and the second grinding disc 16 to prevent that the blade is sprung out due to a collision with the rotary shaft of the motor 11.

[40] Here, as shown in FIG. 14, the blade supporter 36 includes a metal layer 38 formed on the external surface thereof and having a blade groove 37 contacting with the blade 1.

[41] Meanwhile, as shown in FIGS. 1 and 2, the rotary safety switch 18 is connected to the power supply 12 so as to automatically operate when the blade 1 is put into the blade groove 37 and automatically stop the operation when the blade 1 is withdrawn therefrom, and laterally mounted and hinge-coupled under the blade entrance 20a of the main body 10.

[42] Additionally, as shown in FIGS. 5 and 13, the indirect safety switch 19 is hinge- coupled and vertically mounted to a side of the blade entrance 20a of the main body 10

in such a way that the user can manipulate it manually.

[43] So, as shown in FIG. 5, when the user moves the blade-shaped selection lever 30 forwardly to fix it to the multi-stage groove 31 and inserts the double-side blade 1 to the end of the blade entrance 20a of the cover 20, the rotary safety switch 18 is rotated by the blade 1. Just when the user rotates the indirect safety switch 19 with the hand, electric power is applied to the motor 11, and the first grinding disc 15 and the second grinding disc 16 are partially pressurized with each other, so that they are rotated at high speed in a state where they are in contact with the blade 1 in the "V'form to thereby grind a wide area of the blade 1.

[44] In this instance, by virtue of the blade supporter 36 mounted between the first grinding disc 15 and the second grinding disc 16, the blade is not sprung out due to the collision with the rotary shaft 21 of the motor 11 but can be grinded.

[45] Meanwhile, when the user moves the blade-type selection lever 30 backwardly and fixes it to the multi-stage groove 31, since the first pressure roller 171 is moved backwardly in such a way as not to pressurize the first grinding disc 15, only the second grinding disc 16 grinds the blade 1, so that the single-side blade can be grinded.

[46] It is to be appreciated that those skilled in the art can change or modify the embodiment without departing from the scope and spirit of the present invention.

[47] While the present invention has been described with reference to the particular illustrative embodiment, it is not to be restricted by the embodiment but only by the appended claims.