EP0154967A2 - Aiguisoir pour couteau - Google Patents

Aiguisoir pour couteau Download PDF

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Publication number
EP0154967A2
EP0154967A2 EP85102761A EP85102761A EP0154967A2 EP 0154967 A2 EP0154967 A2 EP 0154967A2 EP 85102761 A EP85102761 A EP 85102761A EP 85102761 A EP85102761 A EP 85102761A EP 0154967 A2 EP0154967 A2 EP 0154967A2
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EP
European Patent Office
Prior art keywords
disk
knife
abrasive
cutting edge
sharpening
Prior art date
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Granted
Application number
EP85102761A
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German (de)
English (en)
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EP0154967B1 (fr
EP0154967A3 (en
Inventor
Daniel D. Friel
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Individual
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Individual
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Priority to AT85102761T priority Critical patent/ATE56645T1/de
Publication of EP0154967A2 publication Critical patent/EP0154967A2/fr
Publication of EP0154967A3 publication Critical patent/EP0154967A3/en
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Publication of EP0154967B1 publication Critical patent/EP0154967B1/fr
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B24—GRINDING; POLISHING
    • B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
    • B24B3/00—Sharpening cutting edges, e.g. of tools; Accessories therefor, e.g. for holding the tools
    • B24B3/36—Sharpening cutting edges, e.g. of tools; Accessories therefor, e.g. for holding the tools of cutting blades
    • B24B3/54—Sharpening cutting edges, e.g. of tools; Accessories therefor, e.g. for holding the tools of cutting blades of hand or table knives

Definitions

  • This invention relates to a new and improved method and apparatus for rapidly sharpening knives and similar tools to create a superior cutting edge.
  • knife shall be defined to include any sort of blade such as chisels, plane edges, scissors, razor blades, and similar precision edges or cutting tools.
  • Rapid sharpening requires a means to remove rapidly the material of composition of the knife -- often a high carbon steel or a stainless steel.
  • the rate of metal removal is related to the inherent hardness of the abrasive used, the particle size, or grit as it is commonly called, of the abrasive, the applied pressure on the knife edge, and the linear velocity of the abrasive particles across the edge being formed or sharpened.
  • the hardest material commonly used for metal removal is diamond with a hardness of 10 on the Mohs' scale, compared to about 5.5 or so for many steel alloy knives.
  • Other materials such as alumina, high density alpha alumina, carborundum, certain natural stones and the like also are harder than most steels and hence can be used for sharpening through abrasive action against the metal.
  • any process designed to create such edges is not optimum for the task of initial metal removal such as where a knife is first being formed or where the blade is particularly dull. Consequently, to reduce the total elapsed time needed with a very dull knife to create a thin and fine edge of a thickness limited only by the composition of knife and its crystall-ine structure, one usually resorts to a series of different and time consuming grinding and sharpening operations. None of the integrated sharpening equipment existent today are satisfactory for the rapid generation of fine edges on the order of 1/10,000 inch on otherwise very dull knives.
  • Such grabbing occurs if there is instability in the control of the angle that the knife face makes with the disk face, or inadequate means to hold the knife edge parallel to the flat surface of the disk, or poor control over the consistency of force applied to the knife edge by the disk or operator during sharpening.
  • a major cause of poor sharpening with disk sharpeners is poor control of knife angle relative to the rotating disk such as exemplified in prior art U.S. Patent No. 2,496,139 that actually allows the knife guide to wobble and the sharpening angle to be determined more by operator skill or by the knife width and thickness. Poor control of the knife edge parallel to disk face or poor control of the angle of knife face relative to the principal plane of a disk sharpener is unacceptable if one wishes to optimize blade edge sharpness and to avoid gouging.
  • a complex sharpener covered by U.S. Patent No. 2,519,351 contains two pair, a total of four (4) abrasive blocks, one pair of which is biased to move toward the other, that sharpens by a reciprocating rectilinear motion simultaneously both cutting edge facets of a knife.
  • the knife is held by three sets of jaws in a positioning means designed to be free floating in lateral position between the abrasive pairs and to moderate insertion of the blade into the positioning means by engaging the sides of the knife in one or more of three (3) grooved blocks.
  • this sharpener has the disadvantages inherent in all rectilinear motion sharpeners which leaves a serrated knife edge which cuts by tearing and has poor wear characteristics.
  • U.S. Patent No. 2,751,721 describes a sharpener with a drum shaped abrasive element where the knife cutting edge facet is sharpened against annular portion of the drum surface that rotates in a plane perpendicular to the axis of rotation of the drum.
  • the abrading force on the cutting edge is determined solely by the degree of hand pressure applied to the knife by the operator which leads to significant inconsistencies in abrading rate, poor edge formation, and gouging of the edge -- problems common to much of the prior art.
  • U.S. Patent No. 2,645,063 describes a sharpener with a drum surface and a guide mechanism which provides stops that position the knife by bearing directly on the cutting edge itself. Such stops are impractical because of the constant dulling effect on the edge created by rubbing it directly across and normal to one surface of the guide.
  • This patent and U.S. Patent No. 2,751,721 describe sharpeners that incorporate a magnet. The magnetic field does not support or guide the knife.
  • the disk sharpener described here is equipped with a precision knife guide and a precision non-damaging stop mechanism that acts on just one of the cutting edge facets as part of a knife control system that uniquely positions one knife cutting edge facet in contact with and parallel to that face of an abrasive disk which is perpendicular to its axis of rotation.
  • the guide preferably magnetic, contiguous to the abrasive disk face simultaneously controls precisely the angle of the knife face relative to that face of the disk, and in conjunction with a biasing means acting on the disk controls the level and consistency of force of the abrasive disk against the knife cutting edge facet, and avoids the serious problem of gouging the knife edge common to prior disk sharpeners.
  • the disk and guide means are positioned precisely with the knife removed to be contiguous, defined here as immediately adjacent but restrained from touching.
  • the separation of the disk face and guide is quite small usually less than 1/16 inch.
  • the guide and stop means are aligned so as to insure that the length of the knife cutting edge facet remains parallel to the plane of the disk face while allowing either the disk or the guide means to move relative to the other against a biasing means.
  • biasing means is defined here to include a spring, a solenoid, magnetic effects of a motor armature or other force means that while urging the disk and guide to move closer allows a finite displacement of the disk against the biasing means to insure that biasing force is being applied during sharpening.
  • Biasing action of this sort provided by a spring or other force device in conjunction with the precision stop mechanism insures that the rotating disk will rotate against one edge facet of the knife with a consistent and predetermined force during the sharpening process and thereby establishes precisely the level of abrading force applied.
  • This unique disk sharpener generates rapidly a knife edge on the order of 1/1000 inch or less in thickness, the actual thickness depending significantly on the knife material, abrasive grit size and other factors.
  • the disk in one configuration is equipped with a central hub that protrudes sufficiently beyond the face of the disk to prevent knives from being scored or scratched if they are improperly handled during use of the disk sharpener.
  • an extension of the housing surrounding the disk serves a similar function.
  • the guide preferably magnetic, used to position the knife in this orbital sharpening step commonly positions the face of the knife relative to the plane of the orbiting abrasive surface at an angle, referred to herein as the second sharpening angle, preferably larger than the first sharpening angle between the face of the knife and the plane of the abrasive disk used in the preceding disk sharpening step, referred to herein as the first sharpening angle. This will cause the orbiting abrasive to sharpen the knife cutting edge facets at a slightly greater total included angle than their existing total angle after the disk sharpener.
  • the combination of disk and orbital sharpening is unique because of the overall speed with which a very fine edge is formed.
  • the disk sharpener disclosed here can quickly preform the knife edge which is then passed through the orbital sharpener to develop rapidly a razor like edge.
  • This invention is based on a disk type sharpener used so that the knife edge and cutting edge facet is held parallel to that flat face of an abrasive disk perpendicular to its axis of rotation. That face which is perpendicular to the axis of rotation of the disk and contains the pre- dominent number of surface abrasive elements will be referred to herein as the disk's principal plane.
  • a disk used in this manner has an inherently favorable characteristic compared to grinding wheels, bevel-edge disk sharpeners and rectilinear motion sharpeners in that the abrasive disk as disclosed here moves abrasive elements simultaneously across portions of the knife edge in a variety of directions such as essentially into the knife edge, away from the edge, and in one direction parallel to the edge.
  • a disk so used with a knife positioning system comprised of a guide and two stops for the cutting edge facet of the knife as described herein has further advantage because of the surface planarity of the disk and because of the sizable surface area in contact with the knife edge thereby maximizing the opportunity to retain a straight edge on the knife and minimizing the chances of "grabbing" the knife cutting edge facet and gouging or scalloping the edge.
  • the disk sharpener claimed in this present invention overcomes, through unique design, the disadvantages of prior art abrasive disk sharpeners. Sharpening is carried out on the disk's face perpendicular to its axis of rotation with inherent advantages of varied abrasive motion relative to the knife edge, surface planarity, and low burr formation as compared to sharpening on the bevel edge of the disk. This is accomplished first by employing with the abrasive disk a contiguous precision knife guide but in the absence of the knife there is a small gap usually less than 1/16 inch between the guide and disk.
  • the guide suitably designed can control reliably the knife at a predetermined position and fixed angle relative to the principal plane of the disk irrespective of the knife thickness or shape and contour of the face of the knife.
  • the guide is contiguous to the disk and because its guide face extends along and across the entire disk surface near the sharpening line, it gives unusually good support to the knife and allows precision sharpening of virtually the entire knife edge even with short knives.
  • the knife must be held firmly enough by the guide and in a manner that maintains invariently the relative knife/disk sharpening angle along the entire length of the edge facet being sharpened.
  • this guide is of the magnetic type disclosed in the copending application cited above but other holders can be used.
  • This guide together with other improvements described here assist in eliminating the tendency of prior art disks to grab and often forceably cause the user to lose physical control of the knife when positioned parallel to the disk face, to lose control of the edge sharpening angle and to gouge, scallop or put undesirable grooves in the knife blade.
  • the handle of the knife is positioned by the operator so that the face of the knife rests on the contiguous guide plane established by the face of the guide, which in a preferred case is magnetic, and the knife face is moved downward and toward the disk until the first cutting edge facet contacts the rotating disk, moves the disk some distance against an appropriately selected biasing force, and then comes to rest firmly against two precisely located stops appropriately located contiguous to, defined here as immediately adjacent to but not touching, the circumference of the disk that limit further movement of the knife toward the disk and forceably align that cutting edge facet parallel to the principal plane of the rotating disk.
  • the principal plane of the disk face during displacement remains parallel to its plane in the rest position.
  • the extent of displacement of the disk is determined by the position of the disk face in its rest position and by the location of the stops that act only against the first cutting edge facet, that facet which is also in contact with the face of the disk.
  • the use of such stops across which the cutting edge face of the knife is moved precisely locates that facet during sharpening and in no way damages the cutting edge itself.
  • the rotating disk mounted on the armature shaft of a suitable motor is biased to urge it toward the guide by a means such as a spring, or the force of motor magnetic effects acting on the armature, but means are provided to limit the disk motion so that in rest position with the knife removed the disk face is immediately adjacent to but not touching the knife guide.
  • the force constant of the spring or other biasing means acting on the disk directly or indirectly uniquely determines the force applied by the disk face on the knife cutting edge facet as the knife moves the disk laterally and the cutting edge facet comes to rest on the provided stops. In this manner the disk remains at all times "spring loaded" against the cutting edge facet during sharpening.
  • the motor can be designed to permit enough uninterrupted lateral motion (end play) of the armature and its shaft to accommodate the lateral displacement of the disk between its rest position and its displaced position as established by the position of the cutting edge facet when against the stops. It is convenient to use a leaf spring against the end of the armature shaft opposite the disk to apply the desired biasing force to the disk.
  • the spring can, of course, be located alternatively so as to press directly on the back face of the disk or on some other point along the shaft that supports the disk.
  • the spring force can be essentially uniform with spring displacement or it could be constructed to be non-uniform.
  • the motor can be supported so it can be moved by springs biased in direction of the disk.
  • the disk can be mounted on a separate shaft and driven by means of gears or belts, etc., from the motor shaft where a spring system could act directly on the rear of the disk or on its separate shaft.
  • the stop arrangement disclosed here which acts on the cutting edge facet minimizes the extent of free travel of the disk needed to accommodate the wide variety in size and styles of household knives.
  • Equivalent ability to control the force of the knife's cutting edge facet during sharpening can be realized by allowing the knife holder to move away precisely from a stationary disk to accommodate knives of different thicknesses.
  • the disk is stationary in this latter example in that it is not free to move laterally in a direction along its axis of rotation.
  • a spring or other biasing means would act on the holder in a manner to press it in the direction toward the stationary disk.
  • the holder would be contiguous to but not allowed to touch the disk.
  • the design be such that the required movement of the disk or holder can be realized without any change to the sharpening angle, defined here as that angle formed by the plane of the guide on which the face of the knife rests relative to the principal plane of the abrasive disk, irrespective of blade thickness, width, or length.
  • the disk face or the holder should be allowed to tilt as their relative separation distance changes.
  • the principal plane of the abrasive disk should, during lateral motion of the disk, remain parallel to the principal plane of the disk in its rest position.
  • a part of this invention is a central hub, usually of plastic, on the disk that protrudes just sufficiently from the principal plane of the disk to stop the face of the knife at some point above the cutting edge facet of the knife before it can accidentally contact the abrasive on the disk.
  • the hub must be designed so that it offers this protection without interfering significantly with ability to place and hold the blade edge against the annular portion of the disk.
  • the hub is applicable in disk sharpeners where the edge of the knife contacts the disk substantially below the center of the disk and where the face of the knife passes during sharpening in front of the axis of rotation of the disk. Other protective means are described that are useful irrespective of knife location on the disk.
  • the disk diameter determines in part the force delivered to the knife, and the velocity and mass of the rotating system also influences the force and kinetic energies involved at knife edge if the disk stalls.
  • a disk diameter of 1 to 3 inches and a motor with running torque on the order of 9 inch-ounces works well and minimizes the danger of damaging the knife.
  • a disk diameter of this order provides adequate flat area to spread the sharpening energy over a sufficient knife length to give uniform sharpening action along the cutting edge facet.
  • Disks of other diameters can be used with appropriately selected motors.
  • a friction clutch can be used as another means to control the forces, torques, and energy deliverable to the disk.
  • FIGS 1 through 3 illustrate, by way of example, a preferred configuration of an abrasive disk sharpener 20 incorporating the improvements discussed here.
  • a motor 24 On a base plate 22 is mounted a motor 24 whose left shaft 26 drives disk holder 28 on whose face is mounted an abrasive surfaced disk 30.
  • the disk holder 28 and the abrasive disk are surrounded by plastic enclosure 60 open to expose the abrasive disk to the knife and fastened by screws, not shown, to base plate 22.
  • the base plate 22 is supported on rubber feet 32.
  • the motor shaft 26 and the right armature shaft extension 44 pass through vertical structural support members 34 and 36 attached by screws (not shown) or other means to base 22 and ride in sleeve bearings 38 and 40.
  • a biasing means in the form of a leaf spring 42 supported on the base plate 22 acts against rear armature shaft extension 44 to apply spring force and pressure to rear armature shaft extension 44, free to move some distance laterally, through thrust bearing 46 or other means.
  • the knife 48 in Figures 2 and 3 rests against the knife guide 50 with its cutting edge facet parallel to and against the face of disk 30 rotating in a plane perpendicular to its axis of rotation. Hub 52 on the disk protrudes slightly from the face of disk 30 and prevents accidental contact between a side or upper face of the blade and the abrasive surface of the disk.
  • Stops 54 integrally part of the vertical faces of plastic enclosure 60 opposite the knife guide 50, as shown in Figures 1 through 3, establish in a positive manner the limit of motion of vertical cutting edge facet of the knife in the direction of the abrasive disk 30 and establish positively the position of the cutting edge facet on the disk 30 during sharpening.
  • the stops 54 act only on the vertical cutting edge facet. Those portions of the vertical faces of enclosure 60 that act as the stops 54, are positioned so that when the vertical cutting edge facet is against the enclosure 60 at those points designated as stops 54, the line of that facet is parallel to the principal plane of the abrasive disk.
  • the stopping action can be obtained by designing and locating stops 54 independent of the enclosure 60 but in any event, the stops 54 should be contiguous to but not touching the circumference of the disk holder 28.
  • the stops 54 if made of material independent of enclosure 60 can be made of any of a wide variety of materials such as a high lubricity plastic, a metal such as martensitic steel, a metal roller, or even of a mild abrasive material similarly located that will remove burrs or mildly abrade the facet surface as it is moved over the surface of the stop.
  • a plastic housing 58 encloses the motor 24 and the supporting members 34, 36, etc.
  • the plastic enclosure 60 used to enclose most of the rotating disk holder 28 serves also to minimize any safety hazard from the rotating disk 30.
  • Figure 2 includes in cross section the illustrative knife guide 50 that contains in plastic structure 51 a rigid magnetic element 62 that attracts the knife and establishes a guide plane for the face of the knife.
  • the angle of the face of the knife 48 resting on the guide plane is established relative to the plane of the disk by the rigid magnetic element 62 located at a position primarily adjacent to the knife's lower bevel face 68 as defined graphically in Figure 4.
  • the guide opposite disk 30 is contiguous to but not in actual contact with the face of the abrasive disk 30, separated therefrom by a small gap 56.
  • the lower guide extensions 49 whose upper faces are set as extensions of the guide plane established by the magnetic element 62 to guide the knife face, are in intimate contact with the face of enclosure 60 on each side of disk holder 28.
  • the illustrative knife 48 in Figure 4 has an upper bevel face 66 and a lower bevel face 68.
  • the cutting edge facets 70 of the illustrative knife, Figure 4 converge to form the cutting edge. Movement of the abrasive on the face of rotating disk 30 creates forces on the knife 48 in contact with disk 30 that tend to cause the lower knife bevel face 68 to rest naturally on the rigid magnetic element 62.
  • the disk 30, Figures 1 through 3 rotates preferably at a speed that generates linear circumferential speed of the abrasive particles not greater than 800 feet per minute, the speed above which burning of the knife edge can occur readily.
  • the disk type sharpener can be used with any of a variety of rigid knife guides; however, in order to obtain accurate, reliable and precise control of the sharpening angle an improved guide such as shown is preferred.
  • the hub 52 Figures 1 through 3 that extends from the abrasive surface by a carefully chosen distance, t, (as defined in Figure 5) can be attached to the disk surface as shown or press fitted as a short rod into a center hole in the disk 30 and disk holder 28 of Figures 1 through 3.
  • This hub 52 must not be so thick that it causes the knife 48, Figure 2, to jam between the hub 52 and the face of guide 50 or prevents the cutting edge facet 70 of knife 48 from extending sufficiently toward the gap 56 and against the surface of the abrasive disk 30.
  • the thickness, t, of hub 52, Figure 1 must be at least a few thousandths of an inch or commonly about 10 to 20 thousandths of an inch thick with a 1-2 inch diameter disk--enough thickness to prevent the lower knife bevel 68 from accidentally being jammed against the face of rotating disk 30. Commonly the hub thickness will be less than a few percent of the disk diameter.
  • the hub 52 of Figures 1 through 3 by virtue of its thickness of 10 to 20 thousands of an inch restricts insertion of knife 48 to that space within the clearance angle Figure 2 which by this example would be on the order of 3° less than the sharpening angle 0, commonly about 20°, Figure 2.
  • Sharpening angle 0 is that angle defined by the knife-guiding face of knife guide 50 in Figure 2 and the face of abrasive disk 30.
  • Clearance angle ⁇ is defined by the knife guiding face of knife guide 50 and a line from the cutting edge facet to the left most edge of hub 52.
  • the disk 30 can be of any diameter and rotated at any RPM preferably chosen in combination so that the maximum linear speed of abrasive particles on the disk 30 is less than 800 feet per minute.
  • the knife cutting edge facet 70 of Figure 4 be in contact with the disk sufficiently far from the disk center that it does not encounter the hub.
  • the disk might have a diameter between 1/2 to 3 inches and the hub a diameter of 1/16 to 1/4 inch, a diameter of around 10 percent of the diameter of the abrasive disk itself.
  • the hub can be made of any material, ideally it is of a plastic or similar composition that will not scratch or mar the surface of the knife during sharpening if the knife blade should come in contact with it.
  • the position of the cutting edge of knife 48 relative to where it crosses the face of abrasive disk 30, as shown in Figure 3, is controlled by the height of that point where the guide plane for the face of the knife intersects the plane of the stops for the vertical cutting edge facet.
  • the cutting edge will normally be slightly above that point.
  • the abrasive particles of disk 30 move multidirectionally across the cutting edge facet of the knife. That is, they move across some portion of the knife edge facet in a direction more or less into the edge (upward in Figure 3), while other portions of the knife experience abrasive elements either moving predominantly away from the edge (downward in Figure 3), and in the central area of contact with the knife particles of the abrasive disk more essentially parallel to the knife edge.
  • this disk sharpener is uniquely suited to presharpen the knife before subsequent orbital.sharpening steps that through true omnidirectional abrasive action places a finer edge on the knife on the order of 1/10,000 inch edge width.
  • the knife guide 50c of Figure 13 has a magnetic element 62c located in the surface of the guide 50c at a point above the center of the abrasive disk 30c so as to position the knife's vertical cutting edge facet 70c above the center line of disk 30c.
  • Movement of knife 48c down the face of guide 50c causes the knife's vertical cutting edge facet 70c to contact the face of abrasive disk 30c in its rest plane X-X Figure 13 and to move the disk to the right against biasing means, not shown, that insures full restraining force of spring or other means on the knife vertical cutting edge facet but avoids pushing the disk 30c beyond its limit of free lateral travel to avoid excessive pressures on the knife cutting edge facet and possible gouging of the edge as described herein.
  • stops 54c of enclosure 60c of Figure 13 can be made to be parallel vertically to surface of the disk 30c and hence parallel to the vertical cutting edge facet during sharpening; alternatively the face of stops 54c of enclosure 60c on each side of the disk 30c can be sloped vertically slightly (a few degrees) toward the knife guide 50c so that the heel of the knife's vertical cutting edge facet 70c contacts and slides along the face of stops 54c; or the faces of stops 54c can be sloped vertically slightly away from the knife guide to be more effective in removing burrs and/or abrading slightly the cutting edge facet particularly adjacent to the cutting edge. Stops that function in an equivalent manner need not necessarily be a part of enclosure 60c but could be of separate construction and attachment to base 22c as described herein.
  • a protective projection 72 that can be attached to enclosure 60c located about 1/4 to 1/2 inch above the normal location of vertical cutting edge facet during sharpening and protruding toward the knife guide 50c a distance d, on the order of one to sixty (60) thousandths of an inch beyond the principal plane of the abrasive and beyond that line across the face of enclosure 60c where the knife's vertical cutting edge facet is stopped during sharpening.
  • This projection 72 can be physically part of the enclosure 60c, Figure 13, or a separate physical structure without deviating from the sense of its function here.
  • Biasing action such as created by a spring that applies force on the knife edge during sharpening can be realized either by applying that force to the disk drive and support system as described above where the disk is free to move laterally, and the guide is stationary, or a similar result can be obtained by applying the biasing action and restraining force to the knife guide while maintaining the disk in a stationary position.
  • Figure 5 shows a knife guide 50a and a stationary disk 30a where the guide 50a is free to slide later-ally along the surface 82 of base plate 22a while being pressed to the right by a compression spring 86 located behind the knife guide 50a.
  • the face of knife 48a resting on the guide surface as shown in Figure 5 is moved down the plane of the guide surface toward the abrasive surface until the vertical cutting edge facet contacts the surface of abrasive disk 30a. Any further force than displaces the guide 50a to the left in Figure 5, against the biasing action of compression spring 86 until the lower cutting edge facet contacts stops 89 which are extensions of the guide on each side of the disk.
  • the slope of the upper face of stops 89 is selected normally to be essentially parallel to the lower cutting edge facet. Hence, the upper face of stops 89 is at an angle to the principal plane of the abrasive substantially greater than the angle that the plane of the magnetic element 62a makes with the principal plane.
  • Disk 30a of Figure 5 is stationary in that it is not free to move laterally in a direction parallel to its axis of rotation.
  • the guide 50a moves to the right a distance determined by the guide stop 90 which establishes the rest position of guide 50a and insures that the knife guide 50a will not move against the surface of the stationary rotating disk 30a but remains contiguous to it separated from it by a finite gap 56a. Alignment of the knife guide 50a relative to disk 30a is maintained by shaft 92 that moves through bearing hole 94 in support member 96 fastened to base plate 22a.
  • More than one spring and shaft can be utilized to increase the accuracy of alignment and freer motion of the guide.
  • Stops 89 that act on the lower cutting edge facet Figure 5 should be positioned so that parallel alignment of the vertical knife cutting edge facet 70a relative to the principal plane of the abrasive disk is maintained during sharpening.
  • a hub 52a is shown that functions the same as hub 52 of sharpener 20 of Figures 1, 2 and 3.
  • Angle 9 is the sharpening angle that is the angle between the face of knife guide 50a and the principal plane of the abrasive disk 30a.
  • Angle#° of Figure 5 is the angle between the face of the knife guide 50a and a line extended from the upper terminous of the cutting edge facet 70 to the face of hub52a.
  • the improved disk sharpener of preferred embodiment shown in Figures 1 through 3 disclosed here has been shown to produce very quickly a good edge on a wide variety of knives without scoring, gouging, or otherwise damaging the knife. It has been found also that it produces a minimum burr compared to unidirectional abrasive actions of grinding wheels, beveled disks, hard stones, and the like. This rapid action, the good quality edge, convenience of use, and reduced burr make this an ideal sharpener to be used in combination with the orbital sharpener described in the copending patent application cited above.
  • the orbital sharpener while a relatively fast sharpener removes metal at a slower rate than the disk sharpener for a given grit size.
  • the disk commonly has a relatively coarse abrasive in the range of 100-180 grit.
  • the orbital sharpener can rapidly generate a superior fine, thin edge on the order of 1/10,000 inch wide after first presharpening the knife in the disk sharpener.
  • the absence of a sizeable burr allows final edge formation to occur rapidly with an orbital sharpener.
  • the improved disk sharpener is a particularly unique choice because of reasons discussed herein.
  • Base plate 22b supports motor 24b, fastened to base plate 22b by screws or other means (not shown), whose left shaft 26b drives disk holder 28b on which is mounted abrasive disk 30b that rotates about 3000 RPM but at a maximum surface abrasive circumferential velocity of less than about 800 ft./minute to reduce the risk of overheating the knife edge.
  • Fan 100 mounted on shaft 26b serves to cool motor 24b. Air enters the apparatus through the annulus 102 between upper cover 104 and lower cover 106 and exhausts out a base opening 108 in the base plate 22b which is supported on rubber feet 32b.
  • the knife guide assembly 118 contains plastic structures 148 that support magnetic elements 150 which attract and establish a guide plane for the face of the knife.
  • the knife guide assembly 118 also includes knife stops 152, shown in Figure 11, that serve a variety of functions as described in the copending application cited above.
  • the knife guide 50b used with the abrasive disk 30b contains plastic supporting structure 154 that extends and contacts the face of enclosure 60b. It contains a magnetic element 62b to control the angle of the face of knife relative to the abrasive disk 30b.
  • the magnetic element 62b which attracts the knife and establishes a guide plane for the face of the knife is essentially as described with Figure 2.
  • the drive cranks 134 can be an integral part of shaft 130 as described above or be a separate part affixed thereto.
  • the motor 24b, Figure 12 must be selected such that its armature and shaft 26b, which on the right of the motor is shown as armature shaft extension 44b, has sufficient end-play to allow the necessary movement or displacement of disk 30b in direction along its axis of rotation to accommodate without reaching a travel-limit the thickest knife to be sharpened. Free end-play on the order of 1/16 inch has proven adequate with most knives to allow the disk 30b to be displaced to the right in Figure 12 without reaching the limit of travel permitted by the free end-play.
  • the spring loading concept employed here in conjunction with the stops 54b on the face of enclosure 60b and the blade guide system provides relatively constant force on the blade edge while being sharpened and uniform sharpening action along the length of knife edge without gouging.
  • the enclosure 60b for the disk shown on lower left is designed to provide a safety cover and structure for stops 54b but without interfering with free knife edge insertion between disk 30b and guide 50b and free contact of the cutting edge facet against the surface of disk 30b.
  • Angle 8 is determined by the plane of the guide face on which the blade rests and the plane of the moving abrasive surface, described in the copending U.S. patent application cited above, and shown in Figures 2 and 5. It was found that by using a carefully controlled and slightly larger sharpening angle in successive sharpening steps it is possible to decrease markedly the total sharpening time and insure a superior cutting edge on the blade.
  • the construction of the knife guides for the disk and subsequent orbiting abrasive sharpening steps be very similar so as to position and hold the knife in an essentially uniform manner in each sharpening position except for deliberate changes in the sharpening angle.
  • the blade is given an initial sharpening with a coarse grit disk sharpener but at a precisely determined edge angle that is less than the sharpening angles used in the orbital sharpener that uses generally a finer grit size, a lower velocity of the abrasive elements, and the unique orbital motion that produces a razor-like edge.
  • the knife to be sharpened has its cutting edge facets meeting at an initial total angle of 45°, a popular angle for kitchen knives
  • the disk sharpener sharpen the knife to create a precisely known total angle at the knife edge as established by the two cutting edge facets 70 of Figure 4.
  • This angle should be less than the angle to be created on the facet in subsequent orbiting sharpening stages.
  • a convenient angle of choice might be 34° by way of this example as shown in Figure 6.
  • This sharpening step entails removal of a substantial amount of metal from the edge, a task the disk sharpener with say 100-180 grit is ideally suited to do rapidly with creation of only little burr on the edge. If by chance the initial total blade angle were less than 34°, the disk sharpener would nevertheless generate a 34° angle on the blade.
  • the resulting blade edge shown in Figure 7 with a 34° total included angle then can be sharpened to a razor edge in either a one step or multiple step orbital sharpener.
  • the use of two orbital sharpener steps following disk sharpening makes it possible to use first a faster-working coarser grit followed by a finer grit to leave a smoother edge.
  • the knife of Figure 7 with a 34° total angle is sharpened to a 40° total angle which can be done rapidly with an orbiting abrasive of about 180 grit.
  • This step need entail removal of only a small amount of metal near the edge of the cutting edge facets as seen in Figure 7, compared to the amount of metal removed in the preceding disk sharpener operation.
  • the resulting blade Figure 8 has a 34° total angle along the rear of the cutting edge facet and a 40° total angle nearer to the cutting edge itself.
  • the resulting knife edge of this example shown in Fig. 10 and highly enlarged compared to the scale of starting blade of Figure 6 has three micro bevels along each cutting edge facet 70 that form total angles of 34°, 40°, and 45° respective as one views the knife cutting edge facets at positions progressively closer to the cutting edge. Because that length along the cutting edge facet that is beveled at 45° is very-small, usually less than 0.030 inches, it can be sharpened rapidly with the fine grit orbital sharpener leaving essentially no burr on the edge. Any final micro- burr on the blade edge can be readily removed by pushing the knife edge over and in sliding contact with the knife stops 152 of Figure 11 before the blade edge facet is abraded by the orbiting abrasive 146.
  • a knife sharpened as just described has a significantly superior cutting quality compared to knives sharpened by more conventional means.
  • a knife sharpened according to this example will have three distinct micro bevels on the cutting edge facet as shown in Figure 10. Superior cutting qualities of a cutting edge facet with multiple micro bevels are attributable to the fact that the decreasing bevel angles toward the rear of the cutting edge facet offers angular relief immediately behind the edge that allows the material being cut to tend to move away from or to bear less firmly on the rear portion of the cutting edge facet.
  • a knife with appropriate micro cutting edge facets as created by this invention can remove readily a very fine shaving of material from the surface of a material as contrast to a greater tendency of a knife to split the surface and dig below the surface if the cutting edge facets are planar as a result of being sharpened only at a single angle.
  • Figures 14-15 show an alternative form of the invention using a split disk arrangement.
  • the double disk design has proven particularly effective to permit the operator to sharpen conveniently both cutting edge facets of a knife from the same side of the sharpener.
  • two disks 30d, 30d are secured and positioned back to back on a driven shaft 26d and held apart against stops in their rest positions by a biasing mechanism, such as spring 100, locatod between the two disks forcing the disks apart. Travel of each disk along the shaft axis is limited in one direction by the stop or pin 101 located on the shaft and in the other direction by the position of the second disk or the biasing mechanism.
  • the permissible travel of eaeh disk against the biasing mechanism and toward the opposite disk must be sufficient to avoid the possiblity of the disk reaching its limit of travel against the biasing mechanism at any time while the knife being sharpened is displacing the disk against the biasing mechanism.
  • the disks secured to the stops can slide independently on their common shaft while each is forced to rotate at the shaft speed by a pin 101 fastened to or through the shaft, that engages within a slotted portion 102 of the hub of each disk That pin 101 also can serve as a stop to control position of the disks in this rest position.
  • Other means of driving the disks at shaft speed while allowing the disks to slide on the shaft will be obvious to those skilled in mechanical arts.
  • Abrasive mounted on the outside faces of each disk 30d, 30d rotating on the shaft 26d is pressed against the knife cutting-edge facet during sharpening by a force determined by the spring or other biasing means.
  • the rate of metal removal during sharpening depends on the biasing force and on the size and speed of the abrasive particles.
  • stops 54 may be extended sufficiently toward the disks to prevent the knife blade from being inserted too far and to provide support for the vertical facet. Stops 54 thus would limit the degree of insertion of the knife and limit the displacement of the disk against the sprinq.
  • the invention may also be used by mounting any suitable number of disks on each shaft to achieve different types of abrading action such as coarse and fine or any intermediate treatments.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Finish Polishing, Edge Sharpening, And Grinding By Specific Grinding Devices (AREA)
  • Polishing Bodies And Polishing Tools (AREA)
  • Liquid Crystal (AREA)
  • Particle Formation And Scattering Control In Inkjet Printers (AREA)
  • Mechanical Treatment Of Semiconductor (AREA)
  • Crystals, And After-Treatments Of Crystals (AREA)
  • Electrical Discharge Machining, Electrochemical Machining, And Combined Machining (AREA)
  • Removal Of Insulation Or Armoring From Wires Or Cables (AREA)
  • Paper (AREA)
EP85102761A 1984-03-12 1985-03-11 Aiguisoir pour couteau Expired - Lifetime EP0154967B1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT85102761T ATE56645T1 (de) 1984-03-12 1985-03-11 Messerschleifgeraet.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US58879584A 1984-03-12 1984-03-12
US588795 1984-03-12

Related Child Applications (1)

Application Number Title Priority Date Filing Date
EP89116670.4 Division-Into 1985-03-11

Publications (3)

Publication Number Publication Date
EP0154967A2 true EP0154967A2 (fr) 1985-09-18
EP0154967A3 EP0154967A3 (en) 1986-10-01
EP0154967B1 EP0154967B1 (fr) 1990-09-19

Family

ID=24355332

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Application Number Title Priority Date Filing Date
EP85102761A Expired - Lifetime EP0154967B1 (fr) 1984-03-12 1985-03-11 Aiguisoir pour couteau
EP89116670A Expired - Lifetime EP0349017B1 (fr) 1984-03-12 1985-03-11 Aiguisoir à couteaux

Family Applications After (1)

Application Number Title Priority Date Filing Date
EP89116670A Expired - Lifetime EP0349017B1 (fr) 1984-03-12 1985-03-11 Aiguisoir à couteaux

Country Status (11)

Country Link
EP (2) EP0154967B1 (fr)
JP (2) JPH0661684B2 (fr)
KR (1) KR930007147Y1 (fr)
AT (2) ATE56645T1 (fr)
AU (1) AU577838B2 (fr)
BR (1) BR8501077A (fr)
CA (2) CA1256292A (fr)
DE (2) DE3579712D1 (fr)
IL (1) IL74576A (fr)
NZ (1) NZ211349A (fr)
ZA (1) ZA851702B (fr)

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1988008358A1 (fr) * 1987-04-21 1988-11-03 Grinder Instant Knifes S.R.L. Appareil pour l'affilage d'ustensiles tranchants
DE3819918A1 (de) * 1988-06-11 1989-12-21 Heinz Erath Schleifgeraet
US4996797A (en) * 1988-03-10 1991-03-05 Martek Limited Apparatus for sharpening edge tools
US5148587A (en) * 1990-10-18 1992-09-22 Phelps Carl R Multi-purpose pipeline construction and testing machine
US5397262A (en) * 1993-07-08 1995-03-14 Lii; Chuen-Cherng Knife grinder
DE29620423U1 (de) * 1996-11-22 1998-03-26 Hohlfeldt Petra Electric Schleifvorrichtung
CN104690657A (zh) * 2013-12-04 2015-06-10 林国平 平面式刀具研磨装置

Families Citing this family (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5105582A (en) * 1991-04-17 1992-04-21 Bell Peter M Cup cutter sharpener
IT1256364B (it) * 1992-09-01 1995-12-04 Fazzini Patrizio Macchina perfezionata per l'arrotatura e l'affilatura di lame in genere
JPH09131649A (ja) * 1995-11-10 1997-05-20 Hayashi Kogyo Kk 電動式庖丁研ぎ器
US7740522B2 (en) 2007-07-09 2010-06-22 National Presto Industries, Inc. Knife sharpener
JP2008030197A (ja) * 2007-10-23 2008-02-14 Edgecraft Corp 高速で精密な研ぎ装置
US8043143B2 (en) * 2009-08-07 2011-10-25 Edgecraft Corporation Sharpeners to create cross-grind knife edges
JP5582880B2 (ja) * 2009-07-03 2014-09-03 京セラ株式会社 研磨機
JP5800812B2 (ja) 2009-08-28 2015-10-28 スリーエム イノベイティブ プロパティズ カンパニー 重合性イオン液体混合物を含む組成物及び物品並びに硬化方法
EP2308642B1 (fr) 2009-10-07 2013-12-04 Hans-Peter Zahnd Affûteuse
RU2012131166A (ru) 2009-12-22 2014-01-27 3М Инновейтив Пропертиз Компани Отверждаемые стоматологические композиции и изделия, содержащие полимеризуемые ионные жидкости
US8491356B2 (en) 2010-02-15 2013-07-23 National Presto Industries, Inc. Adjustable knife sharpener

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR396186A (fr) * 1908-11-12 1909-04-03 John Sturtridge Dreadon Meule perfectionnée
FR864572A (fr) * 1940-03-29 1941-04-30 Berkeley Ind Ltd Perfectionnements aux machines pour émoudre ou affûter les lames de couteau et autres
FR1150373A (fr) * 1956-06-02 1958-01-10 Affûteur rectifieur portatif ou fixe à angles variables
US3052068A (en) * 1959-11-09 1962-09-04 Burgess Vibracrafters Inc Knife sharpener
US3146555A (en) * 1962-03-05 1964-09-01 Udico Electric Co Apparatus for opening cans and sharpening knives
GB1454782A (en) * 1973-06-09 1976-11-03 Bisbell Magnetic Products Ltd Permanently magnetic holder for ferromagnetic objects
GB2141953A (en) * 1983-06-24 1985-01-09 Philips Nv Grinding machine

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2841926A (en) * 1954-05-06 1958-07-08 Supreme Products Corp Knife sharpener casing
US3071899A (en) * 1961-02-24 1963-01-08 Gen Electric Knife sharpener
GB1520209A (en) * 1976-06-25 1978-08-02 Olodort R A Film apparatus
JPS6221407Y2 (fr) * 1978-06-26 1987-05-30

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR396186A (fr) * 1908-11-12 1909-04-03 John Sturtridge Dreadon Meule perfectionnée
FR864572A (fr) * 1940-03-29 1941-04-30 Berkeley Ind Ltd Perfectionnements aux machines pour émoudre ou affûter les lames de couteau et autres
FR1150373A (fr) * 1956-06-02 1958-01-10 Affûteur rectifieur portatif ou fixe à angles variables
US3052068A (en) * 1959-11-09 1962-09-04 Burgess Vibracrafters Inc Knife sharpener
US3146555A (en) * 1962-03-05 1964-09-01 Udico Electric Co Apparatus for opening cans and sharpening knives
GB1454782A (en) * 1973-06-09 1976-11-03 Bisbell Magnetic Products Ltd Permanently magnetic holder for ferromagnetic objects
GB2141953A (en) * 1983-06-24 1985-01-09 Philips Nv Grinding machine

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1988008358A1 (fr) * 1987-04-21 1988-11-03 Grinder Instant Knifes S.R.L. Appareil pour l'affilage d'ustensiles tranchants
US4996797A (en) * 1988-03-10 1991-03-05 Martek Limited Apparatus for sharpening edge tools
DE3819918A1 (de) * 1988-06-11 1989-12-21 Heinz Erath Schleifgeraet
US5148587A (en) * 1990-10-18 1992-09-22 Phelps Carl R Multi-purpose pipeline construction and testing machine
US5397262A (en) * 1993-07-08 1995-03-14 Lii; Chuen-Cherng Knife grinder
DE29620423U1 (de) * 1996-11-22 1998-03-26 Hohlfeldt Petra Electric Schleifvorrichtung
CN104690657A (zh) * 2013-12-04 2015-06-10 林国平 平面式刀具研磨装置

Also Published As

Publication number Publication date
JPH0741528B2 (ja) 1995-05-10
AU3971985A (en) 1985-09-19
EP0154967B1 (fr) 1990-09-19
DE3587769D1 (de) 1994-04-07
AU577838B2 (en) 1988-10-06
ATE56645T1 (de) 1990-10-15
EP0349017B1 (fr) 1994-03-02
KR850010622U (ko) 1985-12-30
NZ211349A (en) 1987-07-31
ATE102111T1 (de) 1994-03-15
IL74576A0 (en) 1985-06-30
CA1256292A (fr) 1989-06-27
DE3579712D1 (de) 1990-10-25
EP0349017A2 (fr) 1990-01-03
DE3587769T2 (de) 1994-09-29
EP0349017A3 (en) 1990-12-05
CA1275809C (fr) 1990-11-06
IL74576A (en) 1988-01-31
JPS618266A (ja) 1986-01-14
EP0154967A3 (en) 1986-10-01
JPH0661684B2 (ja) 1994-08-17
ZA851702B (en) 1985-10-30
BR8501077A (pt) 1985-10-29
KR930007147Y1 (ko) 1993-10-13
JPH02160462A (ja) 1990-06-20

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