Abstract:
The present invention is directed to an automatic rotation knife sharpener where the crossed sharpening rods are automatically rotated each time a knife is passed down and through the sharpener. The rotation is derived through the means of a spring steel actuator mechanism making contact with the cogwheels of the sharpening rod holders. Magnets retain the sharpening rods in place within the sharpening rod holders. Sharpening rods may be easily removed and stored in troughs on the upper surface of the protective cover. A variety of sharpening rods with different abrasive surfaces can be easily exchanged in the device.

Description:
FIELD OF THE INVENTION 
     The present application relates to knife sharpeners and more particularly to a knife sharpener with a preset sharpening angle and automatically rotates the sharpening rods after the knife is drawn down through the device. A variety of sharpening rods with different abrasive surfaces can be easily exchanged in the device. 
     BACKGROUND OF THE INVENTION 
     There is a growing need for adequate knife sharpeners that can be used in a commercial application as well as in the home. Frequent sharpening of knives in commercial locations such as restaurants, food processing plants and the like is often required. Knife sharpening services provide sharp knives on a regular basis for these locations but the knives also require frequent dressing of the blade to keep it as sharp as needed. Most individuals at these locations use the hand held sharpening hone that has been used for ages and takes a good deal of dexterity to achieve a good edge along with having the possibility of cutting the operator when the knife is drawn toward the hand holding the honing device. When using this type of hone the angle of the knife is determined by the way the individual is holding the knife and hone, and may very with each stroke of the knife. 
     Various design&#39;s of knife sharpeners have been proposed in the past for purpose of sharpening knives providing some of the improvements needed, such as using the sharpening rods disposed in a crossed relationship giving a precise angle to the edge being sharpened, but requiring the sharpening rods to be turned manually to relocate the sharpening surface. The act of automatically rotating the sharpening rods may seem to be minimal, but during the sharpening action, the knife is often drawn through the device several times. In a commercial application, this operation will occur a great number of times each day. Most of these devices additionally have not addressed the capability of easily changing the sharpening rods to achieve different sharpening surface textures. 
     Numerous innovations for knife sharpeners have been provided in the prior art that are described as follows. Even though these innovations may be suitable for the specific individual purposes to which they address, they differ from the present design as hereinafter contrasted. The following is a summary of those prior art patents most relevant to this application at hand, as well as a description outlining the difference between the features of the automatic rotation knife sharpener and the prior art. 
     U.S. Pat. No. 4,530,188 of Louis N. Graves describes a pocketsize sharpening apparatus of the variety carrying sharpening rods disposed in crossed relationship. The sharpening apparatus has a body with a distal face carrying clips to releasably secure a pair of sharpening rods in crossed relationship. A major access opening permits access to portions of the sharpening rods from a proximal face of the body for sharpening a blade. The major access opening has a V-shaped portion extended inward from a mouth with convergent edges disposed in parallel relationship to and exposing convergent portions of the sharpening rods from the proximal face. A minor access opening is comprised as a slot extending inward of the body toward the major opening a sufficient distance to expose opposite intersecting portions of the sharpening rods. A peripheral protective lip can line the major and minor openings on the proximal face of the body. A groove can be provided in the body wherein the sharpening rods can be seated and manually held in side-by-side, parallel relationship for the sharpening of pointed objects. 
     This patent describes a pocket-sized sharpener with stationary crossing sharpening rods. With this device, the sharpening of a knife will always be on the same surface unless the sharpening rods are removed and replaced in a different position. The device requires that it be held in one hand with the knife held in the other risking injury to the hand holding the device if the knife were to be placed incorrectly. 
     U.S. Pat. No. 4,624,079 of Mario J. Bonapace tells of a knife sharpener having a pair of abrasive rod members whose bottom ends are mounted on carriages that are reciprocally mounted in channels formed in upstanding block members. The channels travel along an axis that is parallel to the downwardly sloping top surface of the block members. The block members are fixedly attached to the top surface of a base and the mouths of their channels face each other and are aligned on parallel offset axes. The rod members therefore intersect each other at a predetermined angle to form a V at their top into which a knife blade is drawn rearward along a horizontal plane to sharpen its edges. Each of the carriages has one of its ends fixedly attached to a spring whose opposite end is fixedly held in position. The downward force of the knife blade as it is being sharpened causes the rod members on the respective carriages to travel downward toward each other and when the pressure is released, the springs will return them to their initial unloaded positions. 
     This patent describes a knife sharpener having a pair of abrasive rod members whose bottom ends are mounted on carriages. This is another knife sharpener with crossing sharpening rods having the same problem where the sharpening action takes place on the same location of the sharpening rods, unless they are physically removed and repositioned. 
     U.S. Pat. No. 4,646,477 of William M. Robertson discloses a knife sharpener that includes a pair of arms pivoted together at their inner ends about a shaft to provide continuous adjustment of the angular orientation between sharpening sticks which are seated in the outer ends of the handles for continuous rotational adjustment, in order to provide precise sharpening. 
     This patent describes another knife sharpener with crossing sharpener rods. The sharpening rods may be rotated within their holders manually, but the holders are on a pivot allowing for different angle preferences. The sharpening rod holders do not have an adequate securing device to hold them in position. The device must also be held in one hand directly below the sharpening action of the knife blade. 
     U.S. Pat. No. 6,881,137 of Daniel D. Friel, Sr. describes a sharpener for blades that comprises a physical structure supporting at least one abrasive surface. A displaceable guiding plate having an integral linear structural feature of the support is disposed toward one side of the abrasive surface. The linear structural feature provides sliding contact with a face of the blade to establish the relative angle of the plane of the edge facet of the blade with the plane of the abrasive surface at the point of mutual contact as the facet is guided into contact with the abrasive surface. 
     This patent describes a structure supporting at least one angled abrasive surface. The knife rest against a guide surface during the sharpening operation but will always make contact with the same surface unless that surface is manually rotated. 
     U.S. Pat. No. 4,912,885 of Mario J. Bonapace describes a knife sharpener having a base, a pair of leg assemblies, a cover, and a pair of rod members formed of abrasive material. The leg assemblies each have an elongated leg member having a pivot pin passing downwardly there through to secure the leg member to the top surface of the base. The pivot ends of the respective leg assemblies are secured to the base at a position adjacent each other so that their free motion ends can pivot toward and away from each other. A spring is connected to the leg assemblies for maintaining a pressure that will force the free motion ends of the respective leg members apart from each other. The rod members are detachably supported in apertures formed in the top surface of the free motion ends of the respective leg members and the respective apertures are angularly oriented toward each other so that the rod members cross paths with one another to form a V and it is within this V that the blade of a knife would be passed in order to sharpen the cutting edge of the knife. The downward force of the knife blade when it is being sharpened causes the rod members on the respective leg members to pivot toward each other and when the pressure is released the spring will return them to their initial unloaded positions. 
     This patent of Mario J. Bonapace describes a similar knife sharpener described in this application with many of the same features accept that the sharpening rods do not rotate. The sharpening rods make contact with the knife at the same surface each time the device is used, unless they are manually repositioned. The sharpening rods are not held in place by magnets and are not easily removed. There is no place to store them on the device. 
     U.S. Pat. No. 7,172,500 of Wen-Chiu Wu discloses a knife sharpener that has a housing, a base, a sharpening device and an adjustable device. The housing has a case, a cavity and a slot. The cavity is defined in the case and the slot is defined in the case and communicates with the cavity. The base is mounted on the housing and has a base board and two side walls formed on the base board. The sharpening device is movable mounted on the base and is received inside the housing. The sharpening device has two sharpening arms with sharpening rods. The adjustable device is mounted on the sharpening device mounted between the two sharpening arms. When the knife sharpener is used, the adjustable device is rotated to change the cross-position of the sharpening device. Therefore, a knife may be sharpened at a different site on the sharpening rods for prolonging the life span of the knife sharpener. 
     This patent discloses a knife sharpener that when the device is used, the adjustable mechanism is rotated to change the cross-position on the sharpening rods. Therefore, a knife may be sharpened at a different site on the sharpening rods for a prolonged life span of the knife sharpener. With this device, the sharpening rods are moved up and down but are not rotated automatically along with the fact that the sharpening rods are not easily replaced. 
     None of these previous efforts, however, provides the benefits attendant with the automatic rotation knife sharpener. The present design achieves its intended purposes, objects and advantages over the prior art devices through a new, useful and unobvious combination of method steps and component elements, with the use of a minimum number of functioning parts, at a reasonable cost to manufacture, and by employing readily available materials. 
     In this respect, before explaining at least one embodiment of the in detail it is to be understood that the design is not limited in its application to the details of construction and to the arrangement, of the components set forth in the following description or illustrated in the drawings. The automatic rotation knife sharpener is capable of other embodiments and of being practiced and carried out in various ways. In addition, it is to be understood that the phraseology and terminology employed herein are for the purpose of description and should not be regarded as limiting. As such, those skilled in the art will appreciate that the conception, upon which this disclosure is based, may readily be utilized as a basis for designing of other structures, methods and systems for carrying out the several purposes of the present design. It is important, therefore, that the claims be regarded as including such equivalent construction insofar as they do not depart from the spirit and scope of the present application. 
     SUMMARY OF THE INVENTION 
     The principal advantage of the automatic rotation knife sharpener is that when a knife is passed down and over the sharpening rods they are automatically rotated where a different surface will be used during the next pass of the knife through the device. 
     Another advantage of the automatic rotation knife sharpener is having magnets in the base of the sharpening rod holder cavities to allow easy removal or for using sharpening rods with different abrasive surfaces. 
     Another advantage is the rod holders will also accommodate ceramic sharpening rods by the means of a steel cap fit over the end of the ceramic rods making them secure to the magnets in the base of the sharpening rod holder central cavities, and enabling a slip fit on and off the device. 
     Another advantage is the automatic rotation knife sharpener can be placed on a surface with the knife held in one hand and the other hand clear from the sharpening operation. 
     Another advantage with the automatic rotation knife sharpener is having a precise angle maintained for the knife as it passes over the sharpening rods. 
     Another advantage of the automatic rotation knife sharpener is having the sharpening rods and rod holders attached to spring loaded arms that keep a constant uniform pressure on the knife blade as it is drawn down through the device. 
     And still another advantage to the automatic rotation knife sharpener is that the sharpening rods can easily be removed and inserted into the two troughs on the top surface of the protective cover for storage of the device. 
     These together with other advantages of the automatic rotation knife sharpener, along with the various features of novelty, which characterize the design, are pointed out with particularity in the claims annexed to and forming a part of this disclosure. For a better understanding of the automatic rotation knife sharpener, its operating advantages and the specific objects attained by its uses, reference should be made to the accompanying drawings and descriptive matter in which there are illustrated preferred embodiments of the automatic rotation knife sharpener. There has thus been outlined, rather broadly, the more important features of the design in order that the detailed description thereof that follows may be better understood, and in order that the present contribution to the art may be better appreciated. There are additional features of the automatic rotation knife sharpener that will be described hereinafter and which will form the subject matter of the claims appended hereto. 
     The preferred embodiment of the automatic rotation knife sharpener will consist of a protective cover in an angular shape covering the top and sides, having two or more storage troughs on the top surface with a circular flexible retainer for the sharpening rods. An elongated orifice at the rear provides a means for the sharpening rods to translate back and forth through the protective cover during the sharpening operation. A slot at the back of the elongated orifice allows for clearance when the knife is drawn through the device. Three screws attach the protective cover to the two round pedestals mounted on the back of the automatic rotation knife sharpener frame and to the rectangular pedestal in the front. 
     Right and left pivot arms are attached to the frame by the means of socket head shoulder screws attaching through nylon washers. The right pivot arm has an extension with a Teflon® insert that mate with a depression in the left pivot arm creating a means whereby the right and left pivot arms rotate inwardly in unison. Flats on the forward distal ends of the right and left pivot arms abut the rectangular pedestal in the front of the device when the pivot arms are in the static position. A compression spring holds the right and left pivot arms apart while in the static position. Nylon glide pins provide additional support against the frame member for the right and left pivot arms when they translate back and forth in the sharpening operation. At the rear distal end of the right and left pivot arms are orifices at opposing angles of twenty-two degrees off perpendicular to the automatic rotation knife sharpener frame. The orifices are offset to separate the sharpening rods. It must be understood that varying angles may be required for different sharpening requirements and will remain within the scope of this application. Sharpening rod holders with a Teflon® bushing will seat into the angled orifices in the left and right pivot arms. A variety of sharpening rods with different abrasive surfaces can be easily exchanged in the device. The device can be used to sharpen scissors and scissor blades as well as knife blades. 
     The sharpening rod holders will consist of a lower pivot shaft with a cogwheel central portion including a boss on the top surface. An orifice extends through the sharpening rod holder that will have a slip fit for the metallic sharpening rods, and accommodate a steel end cap placed over the end of ceramic sharpening rods, for a similar slip fit attachment. Sharpening rods may be made from natural or synthetic materials such as diamond coated metal, ceramic, and/or stone. The lower section of the orifice is enlarged to incorporate a magnet to secure the metallic sharpening rods within the sharpening rod holders. The enlargement of the orifice in the lower section retains the magnet when the metallic sharpening rods are removed. Sharpening rod holder retainers are attached to the rear distal ends of the left and right pivot arms by the means of a screw. The sharpening rod holder retainers have been designed to hold the sharpening rod holder in position when the sharpening rods are removed from the resisting force of the magnets. A spring steel actuator is centrally mounted on an actuator mounting block and extends outwardly on each side to engage with the cogwheels on the sharpening rod holders. 
     When a knife blade is drawn downwardly through the two sharpening rods, the right and left pivot arms are drawn inwardly and the distal ends of the spring steel actuator engage in the cogwheels and rotate them into a new position. When the left and right pivot arms are forced back to their static position by the compression spring the distal ends of the spring steel actuator will re-engage in the next positions on the cogwheels. This action, which is similar to a conventional clock mechanism, produces the automatic rotation of each sharpening rod of the automatic rotation knife sharpener. 
     While the present automatic rotation knife sharpener has been described herein with reference to particular embodiments thereof, a latitude of modification, various changes and substitutions are intended in the foregoing disclosure. It will be appreciated that in some instance some features of the design will be employed without a corresponding use of other features without departing from the scope of the application as set forth. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings, which are incorporated in and form a part of this specification, illustrate embodiments of the automatic rotation knife sharpener and together with the description, serve to explain the principles of this application. 
         FIG. 1  depicts a perspective view of the automatic rotation knife sharpener with the protective cover raised above the frame assembly. 
         FIG. 2  depicts an exploded perspective view of the automatic rotation knife sharpener frame assembly. 
         FIG. 3  depicts a section view of one of the knife sharpener rod holders with a sharpener rod inserted. 
         FIG. 4  depicts a top view of the right pivot arm. 
         FIG. 5  depicts a section view of the right pivot arm. 
         FIG. 6  depicts a top view of the left pivot arm. 
         FIG. 7  depicts a section view of the left pivot arm. 
         FIG. 8  depicts a rear view of the automatic rotation knife sharpener frame assembly. 
         FIG. 9  depicts a rear view of the automatic rotation knife sharpener. 
     
    
    
     For a fuller understanding of the nature and advantages of the automatic rotation knife sharpener, reference should be had to the following detailed description taken in conjunction with the accompanying drawings which are incorporated in and form a part of this specification, illustrate embodiments of the design and together with the description, serve to explain the principles of this application. 
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring now to the drawings, wherein similar parts of the automatic rotation knife sharpener  10  are identified by like reference numerals, there is seen in  FIG. 1  a perspective view of the automatic rotation knife sharpener  10  with the protective angular shaped cover  12  raised above the frame assembly  14 . The protective cover  12  is in an angular shape having a front section  16  and a right rear lobe  18  and a left rear lobe  20  with a protective cover top surface  22  and side surfaces  24  and  26 . Two or more storage troughs  28  on the top surface  22  will hold the sharpening rods  30  and  32  when the device is stored. A circular flexible retainer  34  covering a portion of the troughs  28  for the sharpening rods  30  and  32  holds them in place. An elongated orifice  36  at the rear provides a means for the sharpening rods  30  and  32  to translate back and forth through the protective cover  12  during the sharpening operation. A clearance slot  38  at the back of the elongated orifice  36  allows for clearance at the rear when a knife is drawn through the device. Three cover mounting screws  40  attach the protective cover  12  through three orifices  42  into two round pedestals  44  and  46  mounted on the right lobe section  48  and the left lobe section  50  of the automatic rotation knife sharpener frame base  52  and a rectangular pedestal  54  is mounted in the front section  56 . 
     The frame assembly  14  more clearly defined in the exploded view in  FIG. 2  consists of a frame base  52  resting on three cushion pads  58 . A right pivot arm  60  and left pivot arm  62  are attached to the frame base  52  by the means of socket head shoulder screws  64  through orifices  65  in the right and left pivot arms  60  and  62 . Two nylon washers  66  hold the right and left pivot arms  60  and  62  away from the frame base  52 . The right pivot arm  60  has an extension  68  with Teflon® insert  70  that mates with a depression  72  in the left pivot arm  62  creating a means whereby the right and left pivot arms  60  and  62  rotate inwardly in unison. Flats  74  on the forward distal ends  76  and  78  of the right and left pivot arms  60  and  62  abut the rectangular pedestal  54  in the front section  56  of the device when the pivot arms  60  and  62  are in the static position. A compression spring  80  holds the right and left pivot arms  60  and  62  apart in the static position. 
     Nylon glide pins  82  are inserted in orifices  83  providing additional support for the right and left pivot arms  60  and  62  when they translate back and forth in the sharpening operation. At the rear distal end  84 , of the right pivot arm  60  and the rear distal end  86  of the left pivot arm  62  are orifices  88  and  90  at opposing angles of twenty-two degrees off perpendicular to the automatic rotation knife sharpener frame base  52 . 
     The orifices  88  and  90  are offset to separate the sharpening rods  30  and  32 . Sharpening rod holders  92  are identical with a Teflon® bushing  96  that will seat into the angled orifices  88  and  90  in the left and right pivot arms  60  and  62 . The sharpening rod holders  92  illustrated in  FIG. 3  will consist of a lower pivot shaft  100  with a cogwheel central portion  102  including a boss  104  on the top surface. A central orifice  106  extends through the sharpening rod holders  92  that will have a slip fit for the metallic sharpening rods  30  and  32 . The lower section  108  of the orifice  106  is enlarged to incorporate a magnet  110  to secure the metallic sharpening rods  30  and  32  in place. The enlargement of the orifice lower section  108  retains the magnet  110  when the metallic sharpening rods  30  and  32  are removed. 
     A right sharpening rod holder retainer  114  and a left sharpening rod retainer  116  are attached to the ends of the left and right pivot arms  60  and  62  by the means of a screw  118 . They hold the sharpening rod holders  92  in position when the sharpening rods  30  and  32  are removed from the resisting force of the magnets  110 . The right sharpening rod holder retainer  114  and a left sharpening rod retainer  116  are canted at opposing angles to match the inclined angles of the orifices  88  and  90  for holding the sharpening rod holders  92  in position. 
     A spring steel actuator  120  is centrally mounted on an actuator mounting block  122  by the means of a screw  123  and extends outwardly on each side to engage with the cogwheel central portion  102  on the sharpening rod holders  92 . When a knife is drawn downwardly through the two sharpening rods  30  and  32 , the right and left pivot arms  60  and  62  are drawn inwardly and the distal ends  124  and  126  of the spring steel actuator  120  engage in the cogwheel central portion  102  of the sharpening rod holder  92  rotating them into a new position. When the left and right pivot arms  60  and  62  are forced back to their static position by the compression spring  80  the distal ends  124  and  126  of the spring steel actuator  120  will re-engage in the next positions on the cogwheel central portion  102  of the sharpening rod holder  92 . This action produces the automatic rotation of each of the sharpening rods  30  and  32  for the automatic rotation knife sharpener  10 . Ceramic sharpening rods will have metallic, typically steel, end caps to provide for a slip fit on and off the device. The steel end caps will secure to the magnets within the sharpening rod cavities, holding them securely in place on the device while the device is in operation. 
       FIG. 4  depicts a top view of the right pivot arm  60  illustrating the right pivot arm extension  68  with the Teflon® insert  70  held in place by the means of pin  128  and further illustrated in  FIG. 5 . The Teflon® insert  70  maintains a smooth action against the depression  72  in the left pivot arm  62  illustrated in the top view of  FIG. 6  when a knife blade is drawn through the device. It should be noted that scissors and scissor blades could also be sharpened by the present invention. 
       FIG. 7  depicts a section view of the left pivot arm  62  further defining the twenty-two degree angle of the left pivot arm orifice  90 . 
       FIG. 8  depicts a rear view of the automatic rotation knife sharpener frame assembly  14  while  FIG. 9  depicts a rear view of the automatic rotation knife sharpener  10  illustrating the location of the clearance slot  38  in the protective angular shaped cover  12 . 
     The automatic rotation knife sharpener  10  shown in the drawings and described in detail herein disclose arrangements of elements of particular construction and configuration for illustrating preferred embodiments of structure and method of operation of the present application. It is to be understood, however, that elements of different construction and configuration and other arrangements thereof, other than those illustrated and described may be employed for providing a automatic rotation knife sharpener  10  in accordance with the spirit of this disclosure, and such changes, alternations and modifications as would occur to those skilled in the art are considered to be within the scope of this design as broadly defined in the appended claims. 
     Further, the purpose of the foregoing abstract is to enable the U.S. Patent and Trademark Office and the public generally, and especially the scientists, engineers and practitioners in the art who are not familiar with patent or legal terms or phraseology, to determine quickly from a cursory inspection the nature and essence of the technical disclosure of the application. The abstract is neither intended to define the invention of the application, which is measured by the claims, nor is it intended to be limiting as to the scope of the invention in any way.