HK1129212B - Improved sharpener for blades of food slicers - Google Patents

Description

Improved sharpener for food slicer blades

Cross Reference to Related Applications

The invention is based on provisional application No.60/778,736 filed on 3.3.2006.

Background

There are a wide variety of sharpeners for slicer blades. Most of these are permanently mounted on the food slicer and are easily activated when the slicer blade becomes dull from use and needs sharpening.

Currently available sharpeners are typically designed specifically for a particular slicer with a particular blade size. Virtually all commercially available sharpeners are designed to sharpen only sharp-edged blades, and they are not recommended or recommended for serrated blades. Many modern microtomes, especially for home use, use serrated blades because they are more efficient and require less force to effect cutting than sharp-edged blades. Typically, serrated blades must be sharpened by hand. Sharp-edged blades are not as effective as serrated blades when dulled. However, both types of blades are used on modern slicers and therefore the sharpener should theoretically be able to sharpen either type of blade.

There is a need for a sharpener that can be used on a wide variety of food slicers made by different manufacturers. None of the existing sharpeners are of a design that is versatile enough to accommodate a wide variety of blade sizes, and to accommodate a variety of food carriers that are provided to propel food onto the blade. Existing food slicers are sold for home use along with blades having a wide range of diameters from about 6 "to 12", and larger blades if used for commercial sale purposes.

Disclosure of Invention

The slicer blade sharpener described in the subsequent sections herein is a universal sharpener because it can sharpen blades of different diameters in a wide range of diameters from 6 "to greater than 12"; its unique design allows it to sharpen flat edge blades and serrated edge blades; it is designed to accommodate a variety of food carrier designs and different sizes; and it has a protective sleeve to protect the user's fingers when the slicer blade is sharpened.

Drawings

FIG.1 is a side view of a food slicer;

FIG.2A is a side view of a food slicer knife;

FIG.2B is an enlarged view of the portion of the food slicer knife encircled in FIG. 2A;

FIG.2C is a cross-sectional view taken along line 2C-2C of FIG. 2B;

fig.3A is a view similar to fig.2B of an alternative form of a food slicer knife.

FIG.3B is a cross-sectional view taken along line 3B-3B of FIG. 3A;

figure 4 is a partial side view in section of a food slicer sharpener according to the present invention;

figure 4A is a schematic side view depiction of a slicer blade and sharpener;

figure 5 is a top plan view of the sharpener shown in figure 4;

figure 5A is a top plan view of a modified form of sharpener according to the present invention;

figure 6 is an end view of the sharpener shown in figures 4-5;

FIG.7 is a view similar to FIG. 5;

figure 8 is a cross-sectional view showing a control arm used in the sharpener of the present invention; and

fig.9 also illustrates the control arm shown in fig.8.

Detailed Description

General design of modern microtomes

In fig.1, a modern food slicer 1 provides a motor-driven circular blade 3 supported on a rigid plastic or metal base structure 5. The food to be sliced is placed on a movable food carriage 7, which food carriage 7 can be manually or mechanically advanced along a support platform 9 when the food contacts the moving blade. In manual mode, the operator pushes the food on the food carriage 7 past the blade, forcing the food slices to be cut out and fall along the sides of the blade where they can be collected on a plate or dish. Generally, the food carriage is designed with a pusher bar 11 which is not only conveniently used to push the carriage, but also to guide a food pusher (not shown) needed to press the food against the slicer blade and the thickness control plate 13 when the food is cut into slices. The thickness of the slice is determined by the position of the thickness control plate surface relative to the cutting edge of the blade. To increase the thickness of the cut sheet, the thickness control plate is moved behind the line and plane of the cutting blade. The thickness control plate can be moved back sufficiently to allow the slices to be more than half an inch thick, but more generally, users prefer very thin slices of meat to be similar to 1/16 inches thick. The operator presses a food pusher, which is usually designed to physically hook over the push rod 11, to push the food and press it firmly onto the thickness control plate as it is sliced to obtain slices of uniform thickness of the food.

Blade of cutter grinding slicer

The sharp-edged slicer blade 3 shown in fig.2A and 2B is beveled on the side of its edge, typically the side facing away from the food, to create a facet 15, as shown in fig.2C. The other side 17 of the blade edge adjacent the food is not beveled.

When the cutting edge of the blade becomes dull in use, the cutting edge bends to assume a blunt profile on the food. Generally, the hardness of the blade determines how long the blade can remain sharp. Harder blades retain a sharp edge for longer. When the blade is sufficiently bent, it appears dull and will tear the food rather than cleanly sever it.

Many inexpensive home slicers use a serrated blade as shown in fig.3A and 3B, which has either a repeating wave pattern as shown in fig.3A or a serrated structure around the circumference of the blade. In some designs, the serrated edge is beveled on both sides of the edge. Typically, these do not cut food well into very thin slices, but serrated blades do not appear dull as quickly as sharp-edged blades. A sharp-edged blade is capable of cutting very thin slices much better than a serrated blade.

When dulling of the sharp-edged blade occurs, it is necessary to place a new bevel 15 on the beveled side. This requires removing that metal from that facet until the deformed edge is removed. During the removal of metal from that facet, a burr is created on the other side of the edge. Those burrs must be carefully removed so that no new burrs are created on the side of the edge that is beveled during its removal. Typically, the burrs created when reshaping the bevel are removed with a very fine polishing pad.

Sharpener of the prior art

Typically, grindstone wheels made of natural silica, alumina or silicon carbide are used to sharpen slicer blades. Coarser grit sizes are used to resharpen the facet, while finer grit is used to remove burrs created during sharpening of the facet. The main disadvantage of using these special abrasive materials is that they abrade and wear quickly making it impossible to maintain a consistent sharpening angle. These abrasives are capable of shaping the beveled edge of the hardened blade, but the facet quickly wears the abrasive sharpening surface and changes its angle. Thus, the sharpening angle varies consistently, and the abrasive surface must be replaced frequently to ensure that the facet is formed at the correct angle.

The wheel sharpeners commonly used to sharpen bevels and remove burrs are very difficult to use. Their mounting configuration is extremely complex to contact the blade facet at the correct angle to ensure that the abrasive surface will rotate in order to effectively sharpen the edge and in order to avoid quickly cutting grooves across the abrasive surface. Typically, the sharpening wheel assembly is permanently mounted on the slicer frame adjacent the blade. It is designed to move slightly from a non-contact storage position into contact with the microtome blade. The rough grinding wheel may be moved relative to the beveled facet and then the fine grinding wheel is brought into contact with the other side of the edge to remove the burr. Most sharpeners in use today are dedicated to or mounted to the frame of the food slicer. U.S. patent 6,709,319B2, U.S. patent 6,190,244B1 and 3,986,304 are typical prior art structures.

Prior art sharpeners, almost universally, are not designed to sharpen serrated blades. Many current sharpeners can damage serrated blades or these serrated blades quickly damage the grindstone. This forces the owner of serrated blade slicers to sharpen serrated blades using manual files, which typically must first be removed from the slicer and then safely sharpen them. Manually sharpening slicer blades with flat files is a very tedious and dangerous operation.

Improved sharpener for slicer blades

The sharpener 23 of the present invention (as shown in figure 4) has many advantages over sharpeners traditionally used for food slicer blades. This new sharpener, almost universally in design, can be used to sharpen blades of a wide variety of different diameters and has been successfully tested on a variety of slicers of different brands and blade sizes up to 12 inches in diameter.

In order to sharpen the slicer blade, the sharpener 23 shown in figure 5 must be precisely aligned relative to the blade 3. These inventors have found that by physically aligning and securing the sharpener body relative to the thickness control plate 13 shown in figure 1, it is extremely convenient and very accurate to angularly align the abrasive sharpening disk 21 relative to the facet 15 of the slicer blade. The thickness control plate is typically rigidly mounted and well aligned in a plane that is always parallel to the surface of the slicer blade. When the thickness control plate is moved to vary the thickness of the individual food slices, that plane of the surface of the thickness control plate remains parallel to the blade surface. It is therefore used as a precision alignment face for one side of the improved sharpener described herein. The push bar 11 on the food carriage 7 as shown in figure 1 is used as the second alignment face for this new sharpener. The surface 25 of the push rod is mounted perpendicular to the thickness control plate 13 and thus perpendicular to the surface of the slicer blade. The surface 25 of the push rod and that surface of the thickness control plate thus form a 90 deg. angled corner. This new sharpener uses these structural features for precise alignment and is made with a 90 angle between two adjacent sides, one side 27 shown in figures 5 and 6 resting on the thickness control plate 13 and the side 29 shown in figures 4 and 5 being seated against the push bar surface 25 shown in figure 1. The sharpener is very precisely aligned with respect to the blade surface and bevel 15 that establish the cutting edge.

The support structure of the new sharpener incorporates a novel design for the side 29 of the sharpener that is aligned relative to the push bar 11 of the food carriage. That side of the sharpener is angled so that the protruding rounded surface 31 shown in figure 4 on that side of the sharpener contacts the face 25 of the push bar at a height generally above the sharpener base. This feature provides a very stable line of contact between the sharpener and the face of the push bar which, on some food carriers, is tilted back toward the user as a convenience in molding the food carrier in which the push bar is an integral part. The long axis of the rounded surface 31 is parallel to the base of the sharpener and thus parallel to the top surface of the food carriage when the sharpener is placed on that surface. This rounded surface on the sharpener extends outward beyond the base of the sharpener so that the rounded surface 31 contacts the push bar. This allows the sharpener to be safely positioned relative to the push rod even if the push rod tapers at its top. This rounded surface is used as the primary contact line between the sharpener and the push rod and prevents the sharpener from tilting onto its concave base and misaligning with the inclined face of the push rod.

This new sharpener 23 has a convenient grip pocket 33 for the user's active finger, which pocket is generally positioned parallel to the rounded surface 31 aligned with and adjacent to the push bar as described above. Thus, in use, a movable finger extending deep into the pocket pulls the rounded surface 31 on that face of the sharpener into firm contact with the push rod and holds the base of the sharpener in close contact with the top surface of the food carriage 7. At the same time, the user slides the 90 degree corner of the sharpener tightly into the corner formed by the push bar and the thickness control plate. The abrasive covered sharpening disk 21 used to sharpen the facet 15 of the slicer blade 3 is securely mounted to the sharpener at a point near the side of the sharpener adjacent the thickness control plate. Alternatively, a physical protrusion structure, other than the rounded surface 31, may be used at this location on the rounded surface 31 to perform the same function of ensuring contact with the angled push rod at that height.

An optional feature for sharpening slicer blades is the incorporation of a compression spring 47 behind the grinding disc 21 shown in fig.5A to hold that grinding disc stationary but in sliding contact with the facet of the rotating slicer blade. The spring is preferably mounted on a shaft supporting the abrasive disc.

To use the sharpener, sharpener 23 is mounted on the retracted food carriage 7 as shown in figure 1 and secured relative to the push rod 11 and thickness control plate 13 as described above. The position of the thickness control plate 13 parallel to the plane of the slicer blade is then adjusted to the appropriate position and the sharpener 23 is moved toward the slicer blade 3 by manually pushing the push rod 11 to advance the food carriage 7 on which the sharpener is located until the surface of the sharpening disk 21 shown in figure 7 lightly contacts the facet 15 on the slicer blade. The blade is almost universally beveled on the rear side of the blade adjacent the retracted thickness control plate. When that side of the sharpener is oriented relative to the thickness control plate, the abrasive surface of the sharpening abrasive wheel 21 (as shown in figure 7) is positioned at an angle a, typically 30 ° to the flat plane of the slicer blade, so that the abrasive surface creates a 30 ° facet on the slicer blade. Most slicer knives are factory ground at an angle of 27 to 29 °. Thus, the sharpener initially creates a small secondary bevel on the facet and repeated sharpening changes the entire facet angle to 30 °.

After the blade 3 is sharpened for about 5-10 seconds, the thickness control plate is retracted or the operator can choose to pull the sharpener back and away from the slicer blade on the food carriage to terminate the sharpening step. The carriage is moved back a sufficient distance to bring honing pad 35, having a surface with finer deburring diamond grit, into alignment with the flat (back) side of the slicer blade's cutting edge. A small activation arm 37 on the sharpener adjacent the handle grip recess 33 is activated to bring the deburring pad 35 into contact with the back side of the blade for only 2-3 seconds to remove the burrs created during the sharpening step. The facets produced in these two steps are formed very well and extremely sharp.

The sharpener 23 shown in figures 4, 5A, 6 and 7 has proven to be universally applicable to a wide range of diameters of sharp edges and serrated slicer blades. Its portable design allows the same sharpener to be used to sharpen a variety of slicers of different brands alternately.

The deburring pad 35 is mounted on a control arm 49 shown in figures 8 and 9, the control arm 49 extending within the sharpener housing and being pivotally supported within the housing by a cylindrical post 52. The control arm terminates at an actuating knob 37 accessible to the user, as shown in fig.7. The spring arm is an integral part of the control arm 49 and is used as a location pad 35 that does not contact the slicer blade 3 until the knob 37 is actuated.

Because the active abrasive surface of the abrasive disc is beveled and diamond abrasive is used, it can be used to sharpen serrated slicer blades when properly positioned. The diamond can withstand the large impact of a single tooth with a serration. By contacting the blade facet at the appropriate point 43 on the beveled surface of the abrasive disc 21, as shown in fig.4 and 4A, the serrated teeth do not "catch" on the rim of the disc. We have found that the serrations can easily snag on the edge of the flat abrasive disk and damage the blade edge and sharpener. The transitional abrasive wear problem common to natural and carborundum stones commonly used in prior art sharpeners is eliminated in this new sharpener by using 100% diamond abrasive. These diamond abrasives are permanently bonded to a metal disc having, for example, a frustoconical shape. The abrasive disc 21 is cast on a plastic supporting hub 39 as shown in fig.4, the supporting hub 39 being mounted on a tight fitting metal shaft 41 as shown in fig.5 and 7 to allow smooth rotation of the non-planar abrasive coated disc 21 during sharpening. This rotation is important to distribute any wear of the diamond around the disk surface and to produce a grinding line across the blade facet. The best cutting blade edge is one that is ground across the length of the edge, rather than along the length of the edge.

It has been found that the combined rotation of the abrasive disk 21 and the slicer blade 3 with which it contacts, using the sharpener 23 described herein, can create a desired edge while sharpening only when the abrasive disk is positioned to contact the slicer blade at the point 43 on the abrasive surface that is the optimal location as shown in figures 4 and 4A. The sharpener 23 is shown mounted on a food carriage in the figure (figure 4), the axis of rotation of the abrasive disk must be set at a particular height below the horizontal centerline of the blade. Surprisingly, the particular height relationship proved to be optimal for sharpeners that were mounted as shown in figure 1 regardless of blade diameter. Unfortunately, slicer blades on different brands of slicers are positioned at different heights above the surface of the food carriage, which in turn is used as a support surface for this new sharpener. Thus, this sharpener is designed to allow the height of the sharpening disk to be changed to accommodate the position of the slicer blade.

It has been found that the spatial angular relationship between the abrasive disc 21 and the slicer blade 3 is critical in order to best sharpen a sharp or serrated edge slicer blade 3. It is critical that the profile of the abrasive surface of the disc be beveled, e.g. to approximate a frustoconical surface angled from its axis of rotation,as shown in fig.7. A flat disc presents a hazard in that as a tooth or wave of a serrated slicer blade passes the perimeter of the flat abrasive disc, that tooth may engage the perimeter causing physical damage to the disc and blade. For optimum cutting performance of the slicer knife, it is also highly desirable that the abrasive particles on the abrasive disc contact and move across the blade facet at an angle of about 30-45 degrees from the cutting edge. This results in a sharper blade with increased "bite" required for effective cutting. In order for the abrasive particles to move across the blade in this manner, the radius of the abrasive disc 21 must be sufficiently smaller than the radius of the slicer blade 3. When the power driven rotating slicer blade facet contacts the burr, it causes that smaller burr to rotate about its axis. Because the abrasive disk has a smaller radius, the path of the abrasive particles on its surface can traverse the slicer blade along the shorter radial path of the smaller disk and at an angle to the cutting edge rather than following the larger radius of the slicer blade past the slicer blade facet. For slicer blades in the 7 inch to 12 inch diameter range, the abrasive disc need not be larger than aboutDiameter of inches. It has been found that the optimum point of contact point 43 between the blade face of the slicer knife and the disc surface, as described above, is at a radius of 5/8 to 7/8 inches on the disc and at an angle D of 25 to 60 degrees on the disc, as measured from the centerline drawn between the disc axis and the slicer knife axis, as shown in fig.4A. Please refer to fig.4A.

When the physical sharpener described in this patent application is placed on a dinner plate as described above, the axis of the sharpening disk is ideally mounted at a distance B of about 0.4 to 0.6 inches below the horizontal centerline of the slicer blade, as shown in figure 4, and the point of contact 43 between the blade facet and the disk is placed at a distance C of about 1/16 to 1/4 inches above the horizontal centerline of the slicer blade.

With these relationships, the abrasive disk receives a very positive rotational thrust from the moving slicer blade causing the abrasive disk to rotate freely, while the abrasive particles rub against the edge at approximately 45 ° to the edge of the blade being beveled across the blade face of the slicer.

As a result of the importance of the vertical position and resulting angular relationship between the grinding disk and the slicer knife, the height of the grinding disk must be easily adjusted to accommodate a variety of food slicers. This adjustment allows the body sharpener to work well on a variety of slicers even with large variations in the height of the blade centerline above the surface of the food carriage where the blade sharpener is located. To accommodate this variation between slicers, the support shaft for the abrasive disk is mounted in a slot-like structure 45 that allows the height of the disk on the sharpener to be adjusted.

The abrasive disk used in this preferred construction was about 2 inches in diameter and the frustoconical disk surface was positioned at about 5 degrees relative to a plane perpendicular to the center line of the cone-its axis of rotation.

Claims (13)

1. A sharpener for sharpening the cutting edge of a rotary slicer blade to be positioned on a food carriage of a powered food slicer, the slicer having a thickness control panel and a push rod on the food carriage, the sharpener comprising: a support structure having a base for resting on a carriage, a vertical first wall perpendicular to the base for seating against a thickness control plate, a generally vertical second wall adjacent the first wall, the second wall having a rounded surface that is used as a primary contact between a sharpener and a push rod; a sharpening disk having a non-planar rotatable abrasive sharpening surface mounted above said base and inside said first and second walls, said sharpening surface positioned to contact the cutting edge on one facet of the slicer blade to sharpen the cutting edge; an abrasive surface type deburring pad which is activated to contact an opposite side blade surface opposite to the sharpened cutting edge after the cutting edge is sharpened, and which is positioned so as not to contact the blade; the base, the first and second walls allow the sharpener to be mounted on a slicer without the need for attachment to the slicer during sharpening and deburring.

2. The sharpener of claim 1 wherein said abrasive disk is mounted so that its center line is below the horizontal center line of the slicer blade, said abrasive disk further mounted to cause its abrasive particles to traverse the edge in a manner that the abrasive particles are at an angle of 30-45 degrees to the edge.

3. The sharpener of claim 2 wherein the point of contact between the sharpening disk and the slicer blade is in the range of 5/8 to 7/8 inches from the sharpening disk axis.

4. The sharpener of claim 1 wherein said sharpening surface comprises diamond abrasive particles.

5. The sharpener of claim 1 wherein the vertical position of said abrasive disc on said support structure is adjustable.

6. The sharpener of claim 1, wherein the center of the grinding disc can be positioned 0.4 to 0.6 inches below the horizontal center line of the food slicer blade when placed on the food carriage.

7. The sharpener of claim 1 further comprising a thumb lever that moves said deburring pad into contact with the non-facet surface of the slicer blade.

8. The sharpener of claim 1 wherein said sharpening disk is slidably supported by said support structure and is restrained in position by a spring until moved by contact force between said sharpening disk and the edge of the slicer blade during sharpening.

9. The sharpener of claim 1 wherein said surface of said second wall is inclined.

10. The sharpener of claim 1, wherein said support structure includes a protective sleeve for protecting a user's gripping fingers.

11. The sharpener of claim 10 wherein said protective sheath is a concave recess to protect a user's fingers when sharpening.

12. The sharpener of claim 1, wherein the abrasive surface of the abrasive disc is a portion of a truncated cone.

13. The sharpener of claim 12 wherein said truncated cone is beveled.