阅读说明：本技术 带有用户导向指示器机构的动力锐磨器 (Power sharpener with user-guided indicator mechanism ) 是由 丹尼尔·T·多维尔 于 2019-10-09 设计创作，主要内容包括：工具锐磨器(100,200,300,600,640,650)具有第一导向表面和第二导向表面(610A,610B)以分别支撑邻近第一研磨表面和第二研磨表面(126,128,608,608A,608B)的切削工具(130,160,230)。驱动组件(106,606,614)使第一研磨表面和第二研磨表面相对于第一导向表面和第二导向表面移动。控制电路(280,604)指导用户在第一锐磨操作(686)期间利用第一导向表面将切削工具抵靠第一研磨表面布置,以锐磨工具的切削刃(136,166,236)。控制电路在第一锐磨操作结束时激活指示器机构(298,612,622,644,664)以指导用户执行第二锐磨操作,在第二锐磨操作中,用户利用第二导向表面将切削工具抵靠在第二研磨表面上以锐磨切削刃(692)。(The tool sharpener (100, 200, 300, 600, 640, 650) has first and second guide surfaces (610A, 610B) to support a cutting tool (130, 160, 230) adjacent the first and second abrasive surfaces (126, 128, 608, 608A, 608B), respectively. A drive assembly (106, 606, 614) moves the first and second abrasive surfaces relative to the first and second guide surfaces. The control circuitry (280, 604) directs a user to dispose the cutting tool against the first abrasive surface using the first guide surface during a first sharpening operation (686) to sharpen the cutting edge (136, 166, 236) of the tool. The control circuit activates an indicator mechanism (298, 612, 622, 644, 664) at the end of the first sharpening operation to guide the user to perform a second sharpening operation in which the user uses the second guide surface to urge the cutting tool against the second abrasive surface to sharpen the cutting edge (692).)

1. A sharpener configured to sharpen a cutting tool having a cutting edge, the sharpener comprising:

a first abrasive surface and a second abrasive surface;

a first guide surface configured to contactingly support the cutting tool at a first selected angle relative to the first abrasive surface;

a second guide surface configured to contactingly support the cutting tool at a second selected angle relative to the second abrasive surface;

a drive assembly configured to move the first and second abrasive surfaces relative to the first and second guide surfaces;

an indicator mechanism adjacent to the first guide and the second guide; and

control circuitry configured to direct a user to place the cutting tool against the first grinding surface to sharpen the cutting edge using the first guide surface during a first sharpening operation, and configured to activate the indicator mechanism at the end of the first sharpening operation to direct a user to perform a second sharpening operation in which a user places the cutting tool against the second grinding surface to sharpen the cutting edge using the second guide surface.

2. The sharpener of claim 1 wherein the control circuit is further configured to monitor the first sharpening operation and determine that the first sharpening operation has ended in response to at least one input value generated during the first sharpening operation.

3. The sharpener of claim 1 wherein said indicator mechanism includes a first optical indicator adjacent said first guide surface and a second optical indicator adjacent said second guide surface.

4. The sharpener of claim 3 wherein said first and second optical indicators comprise first and second light emitting devices, respectively, and wherein said control circuit directs the user to perform said second sharpening operation by changing the illumination state of at least one selected light emitting device of said first or second light emitting devices.

5. The sharpener of claim 4 wherein said control circuit is further configured to pre-activate said indicator mechanism to guide the user through said first sharpening operation by changing the illumination state of said first light emitting device, and subsequently through said second light emitting device to guide the user through said second sharpening operation.

6. The sharpener of claim 1 wherein the indicator mechanism includes a movable cover that selectively covers and uncovers the respective first and second guide surfaces in response to an actuator actuated by the control circuit to move the cover.

7. The sharpener of claim 1 wherein said indicator mechanism includes a slidable housing member containing said first guide surface and said second guide surface, wherein during said first sharpening operation said slidable housing member is positioned in a first position to dispose said first guide surface adjacent said first abrasive surface, and wherein during said second sharpening operation said control circuit advances said slidable housing member to a second position to dispose said second guide surface adjacent said second abrasive surface.

8. The sharpener of claim 1 wherein said control circuit includes a timer configured to count a predetermined elapsed time interval during which said first sharpening operation occurs, and wherein said control circuit activates said indicator mechanism to guide the user in performing said second sharpening operation at the end of said predetermined elapsed time interval.

9. The sharpener of claim 1 wherein said control circuit includes one or more sensors configured to sense a condition of a user placing said cutting tool against said first guide surface during said first sharpening operation and a counter configured to accumulate a total number of said conditions, and wherein said control circuit activates said indicator mechanism in response to said total number reaching a predetermined threshold.

10. The sharpener of claim 1 wherein the first and second abrasive surfaces are disposed on at least one annular abrasive belt.

11. The sharpener of claim 1 wherein the first and second abrasive surfaces are provided on at least one rotatable abrasive disc.

12. The sharpener of claim 1 wherein the first and second abrasive surfaces each have the same level of abrasiveness.

13. The sharpener of claim 1 wherein said first abrasive surface has a relatively coarse level of abrasiveness and said second abrasive surface has a relatively fine level of abrasiveness.

14. A sharpener for sharpening a cutting tool, said sharpener comprising:

a first abrasive surface and a second abrasive surface;

an indicator mechanism including a guide surface selectively positionable in a first relative position adjacent the first abrasive surface and a second relative position adjacent the second abrasive surface, the guide surface configured to contactingly support the cutting tool at a selected angle relative to each of the first and second abrasive surfaces;

a drive assembly configured to move the first and second abrasive surfaces relative to a guide surface; and

a control circuit configured to direct initiation of a first sharpening operation by a user in which the user urges the cutting tool against the first abrasive surface with the movable guide surface in the first relative position to sharpen the cutting edge and causes relative movement between the indicator mechanism and the drive assembly to place the guide surface in the second relative position to facilitate a second sharpening operation in which the user urges the cutting tool against the second abrasive surface with the guide surface to sharpen the cutting edge.

15. The sharpener of claim 14 wherein said drive assembly is maintained in a stationary relationship relative to a housing of said sharpener, and said control circuit translates said indicator mechanism relative to said housing to advance said guide surface toward said second abrasive surface.

16. The sharpener of claim 14 wherein said indicator mechanism is maintained in a stationary relationship relative to a housing of said sharpener, and said control circuit translates said drive assembly relative to said housing to advance said second abrasive surface toward said guide surface.

17. The sharpener of claim 14 wherein said control circuit includes a timer configured to count a predetermined elapsed time interval during which said first sharpening operation occurs, and wherein said control circuit activates said indicator mechanism to guide the user in performing said second sharpening operation at the end of said predetermined elapsed time interval.

18. The sharpener of claim 14 wherein said control circuit includes a sensor configured to sense a condition of a user disposing said cutting tool on said guide surface during said first sharpening operation and a counter configured to accumulate a total count of said condition, and wherein said control circuit activates said indicator mechanism in response to said total count reaching a predetermined threshold.

19. The sharpener of claim 14 wherein said control circuitry is further configured to move said first abrasive surface at a first speed during said first sharpening operation and to move said second abrasive surface at a second, lower speed during said second sharpening operation.

20. The sharpener of claim 14 wherein the cutting tool has opposing first and second side surfaces, wherein the guide surface is a first guide surface configured to support the first side surface of the cutting tool adjacent each of the respective first and second abrasive surfaces, and wherein the indicator mechanism further includes a second guide surface configured to support the second side surface of the cutting tool adjacent each of the respective third and fourth abrasive surfaces.

Technical Field

Cutting tools are used in a variety of applications to cut or otherwise remove material from a workpiece. Various cutting tools are known in the art, including, but not limited to, knives, scissors, shears, blades, chisels, bent blades, saws, drills, and the like.

Background

Cutting tools typically have one or more transversely extending, linear or curvilinear cutting edges along which pressure is applied to effect cutting. The cutting edge is generally defined along the intersection of opposing surfaces (bevels) that intersect along a line along the cutting edge.

In some cutting tools (such as many types of conventional kitchen knives), the opposing surfaces are typically symmetrical; other cutting tools, such as many types of scissors and chisels, have a first opposing surface that extends substantially in a normal direction and a second opposing surface that is inclined relative to the first surface.

Complex insert geometries may be used, such as sets of bevels tapering to the cutting edge at different respective angles. Dimples or other discontinuous features may be provided along the cutting edge, such as in the case of a serrated knife.

Cutting tools tend to dull over time after extended use, and it is therefore desirable to sharpen a dull cutting tool to restore the cutting edge to a higher level of sharpness. Various sharpening techniques are known in the art, including the use of grinding wheels, grindstones, grinding cloths, grinding belts, and the like.

Disclosure of Invention

Various embodiments of the present disclosure generally relate to an apparatus for sharpening cutting tools, such as, but not limited to, kitchen knives.

In some embodiments, the tool sharpener has first and second guide surfaces to support the cutting tool adjacent the first and second abrasive surfaces, respectively. The drive assembly moves the first and second abrasive surfaces relative to the first and second guide surfaces. The control circuitry directs a user to position the cutting tool against the first abrasive surface using the first guide surface to sharpen the cutting edge of the tool during the first sharpening operation. At the end of the first grinding operation, the control circuit activates the indicator mechanism to direct the user to perform a second sharpening operation in which the user uses the second guide surface to urge the cutting tool against the second abrasive surface to sharpen the cutting edge.

In other embodiments, the sharpener has a first abrasive surface and a second abrasive surface. An indicator mechanism having a guide surface configured to contactingly support the cutting tool at a selected angle relative to each of the first and second abrasive surfaces is selectively positionable in a first relative position adjacent the first abrasive surface and a second relative position adjacent the second abrasive surface. The drive assembly is configured to move the first abrasive surface and the second abrasive surface relative to the guide surface. The control circuit is configured to direct initiation of a first sharpening operation by a user in which the user urges the cutting tool against the first abrasive surface with the movable guide surface in a first relative position to sharpen the cutting edge and causes relative movement between the indicator mechanism and the drive assembly to place the guide surface in a second relative position to facilitate a second sharpening operation in which the user urges the cutting tool against the second abrasive surface with the guide surface to sharpen the cutting edge.

In a further embodiment, the sharpener has: first and second guide surfaces configured to support a cutting tool adjacent the first and second movable abrasive surfaces, respectively; and an indicator mechanism configured to guide a user to begin a second sharpening operation of the cutting edge against the second movable abrasive surface in response to an output signal indicating an end of a first sharpening operation of the cutting edge against the first movable abrasive surface.

These and other features and advantages of the various embodiments will be understood by reading the following detailed description in conjunction with the accompanying drawings.

Drawings

Fig. 1 provides a functional block diagram for a multi-speed abrasive belt sharpener constructed and operative in accordance with various embodiments of the present invention.

Fig. 2A is a schematic diagram of aspects of the sharpener of fig. 1.

Fig. 2B shows the belt of fig. 2A in more detail.

Fig. 3 is a side view of the sharpener of fig. 1, where fig. 3 provides an orthogonal angle of inclination of the sharpening tool relative to the abrasive belt of fig. 1, in accordance with some embodiments.

Fig. 4 is a side view of the sharpener of fig. 1 according to a further embodiment, wherein fig. 4 provides a blade guide configuration to impart a non-orthogonal angle of inclination to the sharpening tool relative to the abrasive tape.

Fig. 5 illustrates a bevel angle imparted by the sharpener of fig. 3 during a sharpening operation on a kitchen knife, according to some embodiments.

Fig. 6A illustrates another view of the sharpener of fig. 3 with another blade guide configuration in accordance with some embodiments.

Fig. 6B is a top plan view of aspects of the sharpener of fig. 6A.

Fig. 7 is a functional block diagram of a sharpener for a multi-speed grinding disk constructed and operated in accordance with various embodiments of the present disclosure.

Fig. 8A and 8B show respective schematic views of aspects of the sharpener of fig. 7, respectively, when resting and during rotation.

Fig. 8C illustrates the flexible disk of fig. 8A and B according to some embodiments.

Fig. 9A-9C show various views of aspects of the sharpener of fig. 7 to illustrate various tilt angles, bevel angles, and skew angles imparted to a cutting tool according to some embodiments.

Fig. 10A to 10C show the blade portion of the cutting tool of fig. 9A to 9C in various sharpness states.

Fig. 10D to 10F show respective photographs of exemplary cutting tools having various sharpness states shown by fig. 10A to 10C, respectively.

FIG. 11 is a flow diagram of a multi-speed sharpening routine performed in accordance with various embodiments.

FIG. 12 is a functional block diagram of a control circuit operable to adjust a speed of a drive train attached to a media, according to some embodiments.

FIG. 13 is a functional block diagram of a tension adjustment mechanism that provides different output tensions to idler rollers attached to media according to some embodiments.

FIG. 14 is another functional block diagram of the control circuit in combination with a plurality of alternative sensors that may be used to control the multi-speed sharpening process.

Fig. 15A and 15B respectively illustrate views of a multi-speed abrasive belt sharpener in accordance with further embodiments.

Fig. 16 is a flow diagram of a multi-speed sharpening operation performed by the sharpener of fig. 15A and 15B, according to some embodiments.

Fig. 17 is a flow diagram of a multi-speed sharpening operation performed by the sharpener of fig. 15A and 15B according to other embodiments.

Fig. 18 is a functional block diagram of another sharpener constructed and operative in accordance with some embodiments.

Fig. 19 is a schematic view of the sharpener of fig. 18.

Fig. 20 is an isometric view of the sharpener of fig. 17 and 18 in some embodiments.

Fig. 21 illustrates the control circuit of fig. 18 and 19 in some embodiments.

Fig. 22 shows a control circuit in a further embodiment.

Fig. 23 is a schematic depiction of another sharpener constructed and operative in accordance with some embodiments.

Fig. 24A and 24B respectively illustrate views of the sharpener of fig. 23 in some embodiments.

Fig. 25 is a schematic depiction of yet another sharpener constructed and operative in accordance with some embodiments.

Fig. 26A and 26B respectively illustrate views of the sharpener of fig. 25 in some embodiments.

Fig. 27 is a functional block diagram of aspects of another sharpener configured to use one or more alternative indicator mechanisms in accordance with further embodiments.

Fig. 28 is a sequence diagram illustrating the operation of various sharpeners in some embodiments.

Detailed Description

Multi-stage sharpeners are known in the art for providing a continuous sharpening operation to the cutting edge of a cutting tool, such as, but not limited to, a kitchen (chef) knife, to produce an effective cutting edge. One example of a multi-stage sharpener is provided in U.S. patent No.8,696,407, assigned to the assignee of the present application and incorporated herein by reference, which provides a slack belt driven sharpener in which a plurality of abrasive belts may be mounted in series in the sharpener to provide different levels and angles of shaping to achieve the final desired geometry on the cutting tool. Other multi-stage sharpeners are known in the art that use a variety of grinding media, including rotatable grinding wheels, carbon splitters, grinding rods, and the like.

These and other forms of multi-stage sharpeners typically implement a sharpening scheme whereby a coarse sharpening stage is initially applied to quickly remove a relatively large amount of material from the cutting tool, thereby creating an initial blade geometry. One or more fine sharpening stages are then applied to refine the geometry and "hone" the blade to the final cutting edge configuration. In some cases, a relatively larger grit abrasive material is used during rough sharpening, followed by a relatively finer grit abrasive material to provide the final honing blade. The honing operation can remove streaks and other marks left in the blade material by the coarser abrasive material and hone the final cutting edge into a relatively well defined line.

In some embodiments, such as those taught by the' 407 patent, different sharpening angles may be applied to further enhance the multi-stage sharpening process. For example, coarse sharpening may occur at a first angle of inclination (e.g., about 20 degrees relative to the longitudinal axis of the blade), while fine sharpening may occur at a second, different angle of inclination (e.g., about 25 degrees relative to the longitudinal axis of the blade).

While these and other forms of sharpeners have been found to be operable in the production of sharpeners, the use of multiple stages increases the complexity and cost of the associated sharpener. One factor that can increase this complexity and cost is the need to utilize different grinding media to achieve different sharpening levels. For example, the' 407 patent teaches a user to remove and replace different belts having different degrees of wear and different linear stiffnesses to perform different sharpening operations. Other sharpeners provide multiple sharpening stages within a common housing with different abrasive media (e.g., rotatable disks, carbon splitters, abrasive rods, etc.) such that a user inserts the blade sequentially into or against different guide assemblies (guide slots with associated guide surfaces) to perform multiple sharpening operations against different abrasive surfaces.

Accordingly, some embodiments of the present disclosure provide a plurality of different, related sharpeners that can perform multi-stage sharpening operations using a common grinding media. In some embodiments, the common grinding medium is an endless grinding belt. In other embodiments, the common grinding media is a rotatable grinding disk. Other forms of grinding media are contemplated, and thus these examples are merely illustrative and not necessarily limiting.

As described below, rough sharpening operations are typically performed by sharpening the tool against a movable grinding media via a guide assembly. The coarse mode of operation is selected such that the medium moves relative to the tool at a first relative speed. Although not necessarily required, it is contemplated that the first relative velocity is a relatively high velocity in units of distance laterally adjacent the tool relative to time (e.g., X feet per minute, fpm).

A fine (honing) mode of operation is then selected such that the media moves at a second, different relative speed with respect to the tool. It is contemplated that the second speed will be significantly less than the first speed (e.g., Y fpm in the case of Y < X).

In some embodiments, the first removal rate, which is the degree of displacement of material from the cutting edge, is selected to be high enough to form a burr, as explained below. The second material rate is selected to be high enough to remove the burr, but low enough that the lower rate does not significantly alter the basic geometry of the blade.

In some cases, both rough and fine grinding are performed with the media moving in the same direction relative to the tool. In other cases, rough grinding may be performed with the media moving in one direction, while fine grinding may be performed with the media moving in the opposite direction. In further cases, the final pass of the fine grinding operation is performed with the abrasive surface of the media moving toward the cutting edge rather than away from the cutting edge. For example, with a substantially horizontal insert having a cutting edge along its lowest point, the direction toward the cutting edge may be a generally upward direction, while the direction away from the cutting edge may be a generally downward direction. These relative directions may be reversed.

These and other features, advantages, and benefits of various embodiments can be understood from a review of fig. 1, which fig. 1 provides a functional block diagram representation of a powered multi-speed abrasive belt sharpener 100 according to some embodiments. It is believed that a preliminary overview of the various operating elements of sharpener 100 will enhance the understanding of the various sharpening geometries established by the sharpener, as will be discussed below. It should be appreciated that a sharpener constructed and operative in accordance with various embodiments may take various forms, such that the particular elements shown in FIG. 1 are for illustration purposes only and not limiting.

The exemplary sharpener 100 is configured as a power sharpener designed to be placed on an underlying base surface (e.g., a countertop) and powered by a power source (e.g., a residential or commercial Alternating Current (AC) voltage, a battery pack, etc.). Other forms of inclined sharpeners may be implemented, including non-powered sharpeners, hand-held sharpeners, and the like.

Sharpener 100 includes a rigid housing 102, which may be formed of a suitable rigid material, such as, but not limited to, injection molded plastic. The user switch, power supply and control circuitry module 104 includes various elements as desired, including user operable switches (e.g., power supply, speed control, etc.), power conversion circuitry, control circuitry, sensors, user indicators (e.g., LEDs, etc.).

The electric motor 106 rotates a shaft or other coupling member to a transmission assembly 108, which transmission assembly 108 may include various mechanical elements, such as gears, linkages, etc., that in turn rotate one or more drive rollers 110. As described below, the respective modules 104, motors 106, and linkages 108 are configured differently such that, in response to user input, the drive roller 110 rotates at two separate and different rotational speeds. In some cases, three or more separate and different rotational speeds may be used. Although not necessarily required, a change in rotational direction may also be imparted to the drive roller by such a mechanism.

An endless abrasive belt 112 extends around drive roller 110 and at least one additional idler roller 114. In some cases, the sharpener may use multiple rollers (e.g., three or more rollers) to define multiple segments of the belt path. The tensioner 116 may apply a biasing force to the idler roller 114 to provide a selected amount of tension to the belt. The guide assembly 118 is configured to enable a user to present a cutting tool, such as a knife, on a section of the belt 112 between the respective rollers 110, 114 in a desired presentation orientation, as described below.

A schematic diagram of an exemplary tape path is provided in fig. 2A, according to some embodiments. A generally triangular path is established for the belt 112 by using three rollers: a drive roller 110 at the lower left corner, an idler roller 114 at the top of the belt path, and a third roller 120, which may also be an idler roller. It should be appreciated that any suitable corresponding number and size of rollers may be used as desired to establish any number of belt paths, such that in some embodiments a triangular path is used, while in other embodiments a triangular path is not used. The tensioner 116 (fig. 1) is shown as a coil spring operable on the idler roller 114 in a direction away from the remaining rollers 110, 120. Other tensioner arrangements may be used including, for example, a tensioner that applies tension to lower idler roller 120.

The belt 112 has an outer abrasive surface, generally indicated at 122, and an inner backing layer, generally indicated at 124, which supports the abrasive surface. These respective layers are shown generally in fig. 2B. The abrasive surface 122 comprises a suitable abrasive material operable to remove material from the blade during the sharpening operation, while the backing layer 124 provides mechanical support and other features to the belt, such as belt stiffness, overall thickness, belt width, and the like. The backing layer 124 is configured to indirectly engage the respective roller during powered rotation of the belt along the belt path.

The exemplary arrangement of fig. 2A establishes two respective elongated planar segments 126, 128 of the band 112 against which a knife or other cutting tool may be abutted for sharpening operations on alternating sides thereof. Segment 126 extends substantially from roll 114 to roll 110 and segment 128 extends substantially from roll 120 to roll 114. Each of the segments 126, 128 lies generally along a mid-plane that is parallel to the respective axes of rotation 110A, 114A, and 120A of the rollers 110, 114, and 120.

Each segment 126, 128 is further shown as not being supported on the backing layer 124 by a corresponding restraining backing support member. This enables the respective segments to remain aligned along the respective mid-planes in the unloaded state and to be rotationally deflected ("twisted") out of the mid-planes by contact with the knife during the sharpening operation. It is contemplated that one or more support members may be applied to the backing layer 128 adjacent the segments 126, 128, such as in the form of leaf springs or the like, so long as the one or more support members still enable the respective segments to rotationally deflect away from the midplane during the sharpening operation.

Fig. 3 illustrates various aspects of an exemplary sharpener 100 according to some embodiments. A cutting tool 130 in the form of a kitchen (or chef) knife abuts against the section 126 of the belt 112 between the rollers 110, 114. Knife 130 includes a user handle 132 and a metal blade 134 having a curvilinearly extending cutting edge 136. Cutting edge 136 extends to distal tip 137 and is formed along the intersection of opposing sides (not numbered) of blade 134 that taper into a line. Removing, honing and/or aligning material from the respective sides of the blade 134 produces a sharpened cutting edge 136 along the entire length of the blade.

The abrasive belt axis is represented by dashed line 138 and represents the direction of travel and alignment of the belt 112 during operation. The abrasive belt axis 138 is orthogonal to the respective roller axes 110A, 114A of the rollers 110, 114 in fig. 3.

140. 142 represent a pair of knife edge guide rollers. The knife edge guide rollers forming part of the aforementioned guide assembly 118 (see fig. 1) may be made of any suitable material designed to support portions of the cutting edge 136. Other forms of blade guides may be used, including fixed blade guides as described below.

In general, knife edge guide rollers 140, 142 provide a retract path 144 for blade 134 as the user pulls the cutting edge through belt 112 via handle 132. As shown in fig. 3, the retracted path 144 is orthogonal to the abrasive belt axis 138 and parallel to the respective roller axes 110A, 114A. As taught by the' 407 patent, as the user pulls the knife 130 across the band 112, the band 112 will deflect out of the median plane 126 in response to changes in the curve of the cutting edge 136. According to such a degree of curvature, a user may provide an upward movement to the handle 132 during such retraction to maintain the cutting edge 136 in contact with the respective edge guide 140, 142.

Fig. 4 shows another alternative configuration for the sharpener 100 of fig. 1. In fig. 4, the retraction path 144 is not orthogonal to the abrasive belt axis 138. This defines an angle of inclination a between the retraction path and the axis of the belt, which may be on the order of about 65 degrees to about 89 degrees, depending on the requirements of a given application.

While not limiting the scope of the claimed subject matter, the presence of a non-orthogonal bevel angle A as shown in FIG. 4 may result in a more uniform deflection (twist) of the ribbon 112 when the ribbon coincides with the curvilinearly extending cutting edge 136. This generally increases the surface pressure along the leading edge of the band (i.e., the portion of the band closer to the handle) and the associated material release (MTO) rate. The angle of inclination a further reduces the surface pressure and MTO rate along the trailing edge of the tape, i.e., along the portion of the tape closer to the tip of the blade. In this manner, variable surface pressure and MTO rates are provided across the width of the ribbon, which provides enhanced sharpening and less tip rounding adjacent the handle when the tip of the blade encounters the ribbon.

Fig. 5 is an end view of the orientation of fig. 3. In fig. 5, bevel angle B is defined as the angle between the transverse axis 146 of the blade 134 and the belt axis 138. The transverse axis 146 of the blade passes through the cutting edge 136 in a substantially "vertical" direction perpendicular to the show line 144 (see fig. 3). Any suitable bevel angle may be used, for example on the order of about 20 degrees. In this context, the term "bevel" generally refers to the angle from vertical (line 146) along which the opposite side (bevel) of the sharpening blade will be generally aligned. Due to the conformal nature of the belt, the actual sides of the blade may be provided with a slightly convex grinding profile.

Fig. 6A and 6B illustrate additional details of the sharpener 100 of fig. 1 according to some embodiments. Another knife 160, generally similar to the knife 130 of fig. 3-5, is shown to include a handle 162, a blade portion 164, a cutting edge 166, and a distal end 167. The blade is shown inserted into the guide member 168 of the guide assembly 118 (fig. 1). Guide member 168 includes opposing side support members 169, 171 having inwardly facing surfaces adapted to enable alignment of blade 164 at a bevel angle (see fig. 5) during blade presentation relative to the belt through contact engagement. A fixed-blade guide 170 between the side support members 169, 171 provides a fixed-blade guide surface against which a user may contactingly engage a portion of the cutting edge 166 during a sharpening operation. Fig. 6B is a top plan view showing two mirror image guide members 168 abutting respective belt segments 126, 128 (fig. 2). These respective guide members may be used to achieve a sharpening operation on opposite sides of the blade 164.

During the sharpening operation, in some embodiments, the module 104 (see fig. 1) is commanded via user input to rotate the tape in a first direction at a first speed. The user presents the cutting tool (e.g., exemplary blades 130, 160) in the associated guide assembly 118 (see, e.g., fig. 3-6B) and retracts the blades thereon a selected number of times, e.g., 3-5 times. The user may alternate sharpening of both sides of the blade using a dual guide such as shown in fig. 6B. This produces a rough sharpening operation on the blade.

Thereafter, the user provides an input to the module 104 that causes the sharpener 100 to rotate the belt 112 in a second direction at a second speed. The second direction may be the same as or opposite to the first direction. The second speed may be slower than the first speed. Again, the user presents the blade via the guide assembly 118 as before, pulling the blade through the belt 112 a selected number of times, e.g., 3 to 5 times. As before, the user may alternate sharpening of both sides of the blade.

As described above, the final direction of sharpening may be selected such that the belt moves up and over the blade during all or a portion of the fine pattern of sharpening (e.g., in a substantially vertical direction toward the upper roller 114 as shown in fig. 5). Sensors and other mechanisms can be used as required to automatically select a proper sharpening direction; for example, a proximity sensor or pressure sensor in the guide member 168 may be used to detect the position of the blade and select the appropriate direction of movement of the belt 112.

The linear stiffness and wear resistance levels (e.g., grain size levels) of the belt may be selected according to the requirements of a given application. Without limitation, in some embodiments, it has been found that a particle size value of about 80 to 200 may be selected for the abrasive tape, and that effective rough and fine sharpening may be performed using the same common tape as described herein. In other embodiments, the particle size value may be about 100 to 400. The corresponding rotation rate may also vary; for example, a suitable high speed (coarse grinding) rotation rate may be on the order of about 800 to 1500 revolutions per minute (rpm) at the roller, and a suitable low speed (fine grinding or honing) rotation rate may be on the order of about 300 to 500 revolutions per minute at the roller.

In further cases, the lower speed may be about 50% or less than 50% of the higher speed. In still further cases, the lower speed may be about 75% or less than 75% of the higher speed. Other suitable values may be used and, thus, these values are merely exemplary and not limiting. The velocity of the media may be expressed in any suitable manner, including linear travel past the cutting edge (e.g., feet per second, fps, etc.).

As mentioned above, more than two different speeds may be used, for example three speeds or more. The high speed may be used first, then the lower moderate speed, and then the lowest speed that is lower than the moderate speed.

Fig. 7 illustrates another sharpener 200 constructed and operative in accordance with a further embodiment. Sharpener 200 is substantially similar to sharpener 100 discussed above, except that sharpener 200 uses a rotatable media (e.g., an abrasive disk) as compared to an abrasive tape. A similar operating concept is embodied in both sharpeners as will be discussed below.

Sharpener 200 includes a rigid housing 202, a user switch, a power and control circuitry module 204, an electric motor 206, a transmission assembly 208 and a drive spindle 210. As previously mentioned, these elements cooperate to enable a user to select at least two different rotational speeds for the drive spindle 210 via a user input. In some embodiments, different rotational directions may also be produced.

The drive spindle 210 supports a rotatable abrasive disk 212. The guide assembly 218 is positioned adjacent the disc 212 to enable a user to rest a tool against the guide assembly during multiple sharpening operations using the same disc 212.

Although not necessarily limiting, in some embodiments, the abrasive disc 212 may be characterized as a flexible abrasive disc, as shown in fig. 8A and 8B. Fig. 8A shows the disk 212 in a non-rotating (stationary) position. Fig. 8B shows the disc 212 in a rotated (operating) position. During rotation, centrifugal forces (arrows 222) will tend to cause the flexible disk 212 to arrange itself along the mid-plane.

The flexible disk may be formed of any suitable material, including the use of abrasive media on a fabric or other flexible backing layer. In some cases, abrasive material may be disposed on both sides of the disc; in other cases, the abrasive material will be supplied on only a single side of the disc.

Fig. 8C illustrates a general representation of the flexible disk 212 in some embodiments, wherein the abrasive layers 214, 216 are adhered to opposite sides of a central flexible layer 218 made of a woven cloth material. Although not necessarily required, it is contemplated that each of the abrasive layers 214, 216 have a common particle size value (e.g., 80 particle size, 200 particle size, etc.). While the disc is shown as having a cylindrical (disc) shape, other forms of surface may be used, including shaped discs having a frustoconical shape, a shape that extends in a curve, and the like. In a further embodiment, the disc may be arranged such that the sharpening occurs on the outermost peripheral edge of the disc rather than on the facing surfaces as shown in fig. 7-8B.

Fig. 9A-9C show additional views of the flexible abrasive disk 212 of fig. 8A-8B. Exemplary tool 230 (kitchen knife) has a handle 232, a blade portion 234, a cutting edge 236, and a distal point 237. Cutting edge 236 is presented against one side of disk 212 in a suitable geometry to perform a sharpening operation on disk 212. In the case of a flexible disk, the disk may deform along standing waves adjacent the cutting edge, as generally shown in fig. 9B and 9C. The blade portion 234 is presented at a suitable bevel angle C (see fig. 9B) and a suitable offset angle D (see fig. 9C), as desired. A suitable ramp angle may be on the order of about 20 degrees (C ═ 20 °), while a suitable offset angle may be on the order of about 5 degrees (D ═ 5 °). Other values may also be used.

As previously described, the same rotatable disk 212 is used to perform multiple sharpening operations by rotating the disk at different effective speeds. A rough sharpening operation is performed at a relatively high speed of the disc, followed by a fine sharpening operation at a relatively low speed of the disc. Suitable guides may be provided such that each side of the blade 230 is sharpened using the same side of the disk 212 (e.g., by presenting the blade 234 in opposite directions on the layer 214 in fig. 8C) or using the opposite side of the disk from the same general direction (e.g., by presenting the blade 234 in sequence on each of the layers 214, 216).

Fig. 10A, 10B, and 10C are generalized cross-sectional representations of a portion of the blade 244 to facilitate explanation of the multi-speed sharpening process. The blade 244 is generally similar to the blade portions of the example knives 130, 160, and 230 discussed above, and may constitute the lower edge of the blade of a kitchen knife.

Fig. 10A shows a blade 244, the blade 244 having a cutting edge 246 in a dull state requiring sharpening. This can be observed by the rounded nature of the cutting edge. It is noted that the knife in fig. 10A is sharpened using a different initial process (e.g., flat grinding wheel, etc.) to provide opposing flat beveled surfaces 245A and 245B.

Fig. 10B generally shows the blade 244 in a rough condition after a first level of sharpening is applied using the flexible abrasive media (e.g., belt 112, disk 212, etc.) as described above. In fig. 10B, the cutting edge 246 has been thinned, but includes a burr (e.g., a portion of deformed material extending away from the cutting edge). By removing material from the blade, opposing convex (e.g., curvilinear) side surfaces 247A and 247B are formed during the sharpening process.

Fig. 10C generally shows the blade 244 in a finely sharpened state after the second stage of sharpening is applied. As can be seen in fig. 10C, the burr has been removed, resulting in a better defined final geometry of the blade and the sharpened cutting edge 246. The convex side surfaces 247A and 247B retain the same shape and radius of curvature as in fig. 10B, except that the cutting edge 246 is immediately adjacent. Thus, the cutting edge 246 provides a straight or curvilinear extension or extended edge along which the opposing surfaces 247A and 247B converge.

Fig. 10D, 10E, and 10F are photographs of the blade 244 taken during the multi-speed sharpening process described herein. Although different portions along the cutting edge are shown in each picture, the pictures are taken at high magnification (e.g., 500X) for the same blade.

Fig. 10D corresponds to fig. 10A and shows the blade in an initial passive state. Fig. 10E corresponds to fig. 10B and shows the blade after coarse sharpening at a higher grinding media speed. Fig. 10F corresponds to fig. 10C and shows the blade after applying a fine grind and burr removal at a lower speed (for media). It should be understood that the views of fig. 10D-10F are reversed relative to fig. 10A-10C (e.g., the cutting edge appears near the top of each photograph).

The blade in fig. 10D shows a substantially horizontal stripe (score) extending along the length of the blade portion, substantially parallel to the cutting edge. These streaks may represent a sharpening process previously applied to the blade, or marks have been created during use of the blade that result in dulling of the cutting edge. The out-of-focus, unclear nature of the cutting edge indicates that the edge has been flipped or otherwise rounded, which prevents the knife from effectively cutting a given material.

Fig. 10E shows a plurality of stripes that although inclined at a small angle to the right, extend in a somewhat vertical direction. These streaks are created during rough sharpening operations as the media advances at relatively high speeds against the cutting edge and blade side. Rough sharpening results in positive removal, rapid shaping and polishing of the material; while the sides of the blade have been shaped in a substantially curvilinear shape as shown in fig. 10B, the cutting edge remains serrated with a large amount of burr (swollen portion of blade material) protruding upward along the cutting edge.

Fig. 10F shows a blade having a similar stripe pattern as fig. 10E, which is expected because the same presentation angle and the same grinding media were used during the rough sharpening operation and the fine sharpening operation. The lower grinding media velocity does not introduce a significant amount of further shaping to the sides of the blade. However, the lower grinding media velocity does dislodge and remove burrs and other material discontinuities along the cutting edge, thereby forming a sharp, but serrated or toothed cutting edge.

It will be appreciated that at least one conventional multi-stage sharpening operation tends to enhance thinning of the cutting edge, for example by applying progressively thinner abrasive material to further thin the cutting edge to the extent that the cutting edge is burr-free and substantially straight. While such techniques can provide very sharp edges, it has been found that such thinned edges also tend to dull quickly, sometimes after a single use. As discussed above in fig. 10D, the very high surface pressure applied to the very thin small area cutting edge tends to erode or curl the finishing edge, significantly reducing the cutting performance of the finishing edge.

The resulting cutting edge of fig. 10F maintains a degree of serrations or jaggies along the length of the cutting edge. The opposing sides of the blade substantially intersect along a line generally as shown in fig. 10C, but the ridge of this line varies slightly along the length. It has been found that this provides the following cutting edges: the cutting edge not only exhibits exceptional sharpness, but also has significantly enhanced durability, thereby allowing the knife to remain sharp for longer periods of time. It is believed that the serrated cutting edge shown in fig. 10F provides a very small discontinuity that tends to prevent the cutting edge from folding along its length, as is often experienced with a finishing edge. Furthermore, the toothed cutting edge presents a plurality of concave cutting edge portions which maintain the initial sharpness even if other higher raised portions of the cutting edge have become locally dull.

Fig. 11 is a flow diagram of a multi-speed sharpening routine 250 illustrating steps that may be performed to perform the multi-speed sharpening discussed above and produce a sharpened cutting edge as shown in fig. 10F. It should be understood that this routine is applicable to the respective sharpeners 100, 200, as well as other sharpeners configured with movable abrasive surfaces. FIG. 11 is provided to summarize the preceding discussion, but it should be understood that the various steps in FIG. 11 are merely exemplary and may be changed, modified, appended, performed in a different order, etc., as desired for a given application.

Powered multidirectional grinding media and adjacent guide assemblies, such as discussed above with respect to the abrasive belt sharpener 100 of fig. 1 and the abrasive disk sharpener 200 of fig. 7, are provided, as shown at step 252.

The user presents in step 254 a cutting tool for sharpening into the guide assembly, such as the exemplary knives 130, 160, and 230 discussed above. It will be appreciated that other forms of cutting tools may be used in accordance with the present routine.

In step 256, the user pulls the cutting edge of the tool across the media as the media moves at the first speed. As discussed above, this may be done a number of consecutive times, including passing on opposite sides of the cutting tool. It is contemplated that the guide assembly includes at least a first surface that supports a side surface of the blade opposite the media to determine a desired bevel angle for the blade that can be repeatedly sharpened by reference to the side surface.

The insertion depth of the cutting edge may be further determined by using one or more fixed or rotatable edge guides against which a portion of the cutting edge contactingly engages as the blade is pulled across the media. The operation of step 256 will produce a rough-shaped cutting edge, such as that exemplarily shown in fig. 10B.

Once the rough sharpening operation is complete, the user then pulls the cutting tool across the same media, this time moving at a second, different relative speed with respect to the tool, as shown in step 258. As discussed above, this may include performing by providing a suitable input to a motor or other mechanism to slow the rate of linear or rotational movement of the media relative to the tool. This results in a fine-shaped cutting edge, such as is shown by way of example in fig. 10C.

Fig. 12 is a functional block diagram illustrating further aspects of a respective sharpener according to some embodiments. The control circuit 260 (which may include aspects of the respective modules 104, 204 discussed above) may receive and process various input values, including power on/off values, coarse/fine selection values, and values from one or more sensors. In response, the control circuit 260 is configured to output various control values to a drive train (component) module 262, which may correspond to various elements including the motor 106/206, the transmission assembly 108/208, and the drive pulley/spindle 110, 210. The control values ultimately determine the speed and direction of the associated media attached to the drive train.

In some embodiments, different speeds and directions may be generated by applying different control voltages and/or currents to the motor. In other embodiments, different gear ratios or other linkage configurations may be produced via the transmission assembly. As described above, various input values may be generated using user-selectable switches, levers, or other input mechanisms. In some cases, the user may set the system to a coarse mode or a fine mode, and may then utilize the proximity switches to determine placement of the tool in the associated guide, and may select the appropriate direction of movement of the media accordingly.

FIG. 13 is a functional block representation of another mechanism useful according to some embodiments. Fig. 13 includes a tension mechanism 270 in combination with an idler roller 272 or other mechanism. In FIG. 13, the coarse/fine selection value is input to a tension mechanism 270, which tension mechanism 270 in turn applies a relatively high tension or a relatively low tension to idler roller 272.

Such a change in the tensioner biasing force may be provided in addition to, or instead of, a change in the rate of rotation/movement of the medium. It will be appreciated that variations in the respective surface pressures of the media affect the generation of burrs and the relatively large scale formation of the rough grind, as well as the fine grind operation (at low pressures) sufficient to remove the burrs and produce the final desired geometry. Thus, other embodiments may utilize mechanisms other than velocity control to achieve higher and lower amounts of surface pressure to achieve the disclosed coarse and fine formations using the same media.

Fig. 14 illustrates another functional block diagram of a control circuit 280, the control circuit 280 may be incorporated into the various power sharpeners discussed herein, including the belt sharpener 100 of fig. 1 and the disk sharpener 200 of fig. 7. The control circuit 280 may be hardware-based to include various control gates and other hardware logic, as shown at block 282, to perform various functions described herein. Additionally or alternatively, the control circuitry 280 can include one or more programmable processors 284 that utilize programming steps stored in an associated memory device 285 to perform the various described functions.

A plurality of different types of sensors and other electrical based circuit elements may be arranged as desired to provide inputs to the control circuit 280. These circuit elements may include one or more of proximity circuit 286, contact sensor 288, resistance sensor 290, optical sensor 292, timer 294, and/or counter circuit 296. Control output from the control circuit is directed to the motor 106 and to a user Light Emitting Diode (LED) panel 298. While each of these elements shown in fig. 14 may exist in a single embodiment, it is contemplated that only selected ones of these elements will exist and be incorporated into a given device.

Various sensors may be used to detect user operation of the blade by touching and pulling on the media. It is contemplated that various sensors may be separately placed in suitable locations, such as integrated within the guide 168 or adjacent to the guide 168 (see fig. 6A-6B). In some cases, a sensor may be used to measure or count the number of sharpening passes applied by the user during a sharpening operation. Other ones of the sensors may be adapted to monitor changes in the cutting tool itself during the sharpening operation, thereby providing an indication of the progress and effectiveness of the sharpening operation.

While these and other types of sensors are well known in the art, it will be helpful to give a brief overview of each type. The proximity sensor 286 may take the form of a hall effect sensor or similar mechanism as follows: the similar mechanism is configured to sense adjacent proximity of the cutting tool, for example, by changes in field strength of a magnetic field surrounding portions of the cutting tool as the tool moves through the guide. The contact sensor 288 may use a pressure actuated lever, spring, pin, or other member that senses the application of contact imparted by a portion of the cutting tool.

The resistance sensor 290 may create a low current path that may be used to detect a change in resistance of the cutting tool. The sensor may form a portion of the edge guide surface against which the cutting edge is pulled (see, e.g., surface 170 in fig. 6A-6B). If injection molded plastic is used to form the guide, carbon or other conductive particles may be mixed with the plastic to achieve this measurement. Optical sensor 292 may take the form of a laser diode or other source of electromagnetic radiation that impinges on a portion of the cutting edge. The receiver may be positioned to measure the luminosity or other characteristics of the reflected light to assess the condition or change of the cutting edge. For example, it has been found that the cutting edge continues to be refined by removing burrs and other expanding materials to enhance the reflectivity of the cutting edge.

Timer 294 may take the form of a resettable countdown timer that operates to count to a desired value to represent a desired elapsed time interval. Counter 296 may be a simple incremental buffer or other element that enables a running count of operations such as a scrub (stoke) to be accumulated and tracked. The user LED panel 298 may provide one or more LEDs or other identifiers that provide a visual indication to the user to perform various operations.

As described above, one or more sensors such as depicted in fig. 14 may be used in the sharpening process. In one exemplary embodiment, the initial sharpness of the blade is evaluated and determined in response to the user first inserting the blade into the sharpener guide assembly. The control circuit selects an initial velocity for the grinding media that is best suited to address the initial sharpness level of the blade. Detecting a relatively dull (and/or damaged) blade may allow the control circuitry to select a higher initial speed to provide a faster material removal rate. Detecting a relatively sharper blade that requires only a small number of honing enables the control circuit to select a lower initial speed to enable better control of the formation of the cutting edge.

A greater or lesser number of speeds may be selected based on the initial conditions of the blade so that the control circuit generates a unique sharpening sequence. The condition of the blade may also be monitored by one or more sensors, with the control circuit suitably changing from one speed to the next to continue the sharpening process.

In a still further embodiment, a sharpness tester apparatus is contemplated that utilizes a selected combination of the various elements of FIG. 14, such as the control circuit 280, one or more of the sensors/circuits 286-296, and the user LED panel 298 (or other user indicator). As previously mentioned, when a blade is inserted into an appropriate slot or other mechanism, the sharpness tester means will operate to detect the level of sharpness that is currently present for a given blade. However, rather than operating the motor to achieve a particular speed for the abrasive material, the sharpness tester may provide an output indication of the sharpness level to the user based on the detected conditions from the sensor. If one or more sensors determine that there is a sharpness level less than a threshold, this may allow the user to perform some other sharpening process, including sharpening processes that do not involve moving the abrasive media.

Fig. 15A and 15B provide isometric views of a multi-speed abrasive belt sharpener 300 according to a further embodiment. Fig. 15A is an isometric view of sharpener 300 from one vantage point, and fig. 15B is an isometric view of sharpener 300 from another vantage point, and partially cut away to show selected internal components of interest.

In general, sharpener 300 is similar to sharpener 100 discussed above and includes a multi-speed abrasive belt arranged along a triangular belt path that passes over three internally disposed rollers in a manner similar to that discussed above in fig. 2A. The belt path is tilted back away from the user at a selected non-orthogonal angle relative to the horizontal as generally shown in fig. 4. The internal motor rotates the belt along a belt path and includes an output drive shaft parallel to the roller axis and not parallel to the horizontal. Guide assemblies (guide slots) are arranged on opposite sides of the belt, similar to the guides depicted in fig. 6A and 6B, to enable double-sided sharpening operations on the cutting tool. Each of the guide slots may have a leading fixed-blade guide surface and a trailing fixed-blade guide surface, e.g., 170, on opposite sides of the belt in a manner similar to the roller blade guides 140, 142 in fig. 4. Various control circuits such as those depicted in fig. 12-14 may be incorporated into the sharpener, as discussed more fully below.

With particular reference to fig. 15A and 15B, a rigid housing 302 encloses various elements of interest, such as motors, gearing assemblies, rollers, control electronics, and the like. A base support contact feature (e.g., a shim) 304 extends from the base 302, and the base support contact feature (e.g., a shim) 304 extends from the housing 302 and is aligned along a horizontal plane to rest on an underlying horizontal base surface 306 (e.g., a table top, etc.).

Endless abrasive belt 308 is arranged along a plurality of rollers including an upper idler roller 310 and a lower right drive roller 312. The opposing guide slots 314, 316 operate to enable a user to perform a sharp sharpening of the slack tape on a relatively distal extent of the tape. The internal motor drive shaft 318 transmits rotational power to the drive roller 312 via a drive belt 320. A plurality of user-visible LEDs are provided on a user LED panel 322 in front of the sharpener, which can be selectively activated during the sharpening sequence.

Fig. 16 is a flow diagram of a multi-speed sharpening process 400 performed to sharpen a cutting tool (in this case, a kitchen knife), according to some embodiments. The present discussion will consider using sharpener 300 of fig. 15A through 15B, using the sensor and control circuitry selected from fig. 14 and the opposing guide slots to perform this process. This is merely exemplary and not limiting as other embodiments may omit or modify these elements as desired, including the use of a single guide slot.

The process begins with the initial movement of powered grinding media (e.g., belt 310) in a selected direction at a first, higher speed, as shown in step 402. This may be accomplished by the user activating the sharpener or by some other action of the user on the component. The band is disposed adjacent to first and second guide slots (e.g., guide slots 314, 316) adapted to support the knife during a double-sided sharpening operation.

At step 404, the counter 296 is initialized and a user indication is made to signal the user to place the knife in the first guide slot, as desired. This can be performed in a number of ways, for example a blinking or solid-colored LED suitable for the purpose. In one embodiment, an LED may be placed under each slot to signal to the user which slot to use in turn.

In step 406, the user continues to pull the cutting edge of the knife across the moving media multiple times to rough sharpen the first side of the knife in the manner discussed above. In fig. 16, the sharpener uses a sensor (e.g., a contact sensor, a pressure sensor, an optical sensor, a tension sensor, etc.) to detect the number of strokes a user applies in the first slot and increments (or decrements) a counter in response to each stroke. This provides a cumulative count value that is the total number of wipes that have been applied, and this cumulative count value may be compared to a predetermined threshold level. In this way, a predetermined desired number of strokes may be applied, for example 3 to 5 strokes.

At step 408, the counter is reinitialized, and a second user indication may be provided to signal the user to use the second slot, if desired. This may be performed by a different LED or by some other mechanism. It should be appreciated that the use of user indicators such as LEDs is merely exemplary and helps to make the sharpening process user friendly, repeatable and effective. However, such a user indicator is not necessarily required.

In step 410, the user places the knife in the second slot and repeats the rough grinding operation for the second side of the blade. As before, a sensor may be used to detect each wipe, and a counter may be used to count the total number of wipes applied, after which the system signals completion of the rough grind portion of the sharpening process.

The system next operates to reduce the velocity of the media to a second, lower velocity at step 412. As described above, the first roller rpm rate may be on the order of about 1000rpm during rough sharpening, and the rate may be reduced to about 500rpm during fine sharpening operations. Other values may be used.

The foregoing steps are repeated in large numbers at relatively low speeds for fine sharpening. In step 414, the counter is reinitialized and the user is instructed to again place the knife in the first guide slot, as desired. As previously described, the user pulls the tool through the first guide slot a predetermined number of times, as indicated by the counter, at step 416. These steps are repeated for the second guide slot in steps 418 and 420, after which the sharpener provides an indication to the user in step 422 that the sharpening operation is complete, such as by powering off or some other operation, and the process ends in step 424.

A number of variations may be set on the routine of fig. 16. In one embodiment, a timer circuit (e.g., 294 in FIG. 14) sets the desired elapsed time period for each side. For example, the timer may be set to a suitable value (e.g., 30 seconds) and a light or other indicator signals to the user that: as long as the light is still active, the user pulls the knife repeatedly through one of the guides. At the end of the 30 seconds, another light is lit, signaling the user to switch to another director and repeat. The sharpener automatically reduces the speed of the belt and then signals the aforementioned operation again in each slot. This provides an extremely easy to use sharpener that provides superior sharpening results.

Finally, it is contemplated that the media (tape 310) in the routine of FIG. 16 moves in a common direction throughout the routine. In further embodiments, the changing of the direction of the tape (or other medium) may be selectively performed as desired. For example, the tape direction may be alternately changed such that the tape moves down on each side during a rough sharpening operation and up on each side during a fine sharpening operation.

FIG. 17 illustrates another multi-speed sharpening routine 500 similar to the routine 400 in FIG. 16. The routine 500 is also envisioned as being performed by the sharpener 300 according to some embodiments to provide a toothed sharpened edge such as that shown in fig. 10F. In fig. 17, sharpener 300 is configured with one or more sensors (such as, but not limited to, the aforementioned electrical resistance or optical sensors) that sense the state of the cutting edge during the sharpening process.

As previously described, the process begins with step 502, initiating movement of the grinding media (e.g., belt 310) at a first, higher speed. The first sensor is activated at step 504 and, if desired, a signal is sent to the user to use the first guide slot at step 504. At step 506, the user continues to pull the tool through the first slot while the sensor monitors the sharpening process. In this manner, a variable amount of wipe through the first slot may be provided based on changes to the cutting edge. The settings used by the sensors may be obtained empirically by evaluating the sharpening characteristics of a number of different cutting tools.

The second sensor is activated at step 508 and the user continues to pull the blade through the second slot at step 510. A second sensor monitors the sharpening process to detect changes in the cutting edge. This provides an adaptive sharpening process based on the material removal rate of the blade, and may provide better overall sharpening results for various cutting tools having different degrees of damage, dullness, and the like.

Once the higher speed rough sharpening operation is completed, the sharpener reduces the speed of the media to a lower speed, step 512. The foregoing steps are repeated for the low speed fine sharpening operation at steps 514, 516, 518, and 520. As previously described, once the fine sharpening operation is performed, a user indication is provided to signal the completion of the sharpening operation (step 522), and the process ends at step 524.

Fig. 18 provides a functional block representation of another power sharpener 600 constructed and operative in accordance with some embodiments. The sharpener 600 is generally similar to the sharpeners discussed above and includes a rigid housing 602 that encloses selected elements of interest including a control circuit 604, a drive assembly 606, a plurality of abrasive surfaces 608, a plurality of corresponding guide surfaces 610, and an indicator mechanism 612.

The control circuit 604 includes the necessary hardware and/or programmable processor circuitry to provide the highest level of control of the sharpener during operation. The drive assembly 606 operates as generally discussed above to move the abrasive surface 608 adjacent to the guide surface 610. As previously mentioned, the abrasive surface may take any number of suitable forms including, but not limited to, abrasive tape, abrasive discs, and the like. The abrasive surfaces may be disposed on opposite sides of the central substrate, as discussed above with respect to double-sided abrasive disk 212 in fig. 8C, or may be disposed on different media sets. Sharpener 600 may be characterized as a single stage sharpener or a multi-stage sharpener, as desired.

The indicator mechanism 612 generally operates as described below to provide user-guided assistance in advancing a cutting tool (e.g., a knife) from a first guide surface to a second guide surface. More specifically, a first sharpening operation is performed on a first grinding surface among the grinding surfaces using the first guide surface, the first sharpening operation being continued for a certain interval. At the end of the interval, the indicator mechanism instructs the user to begin a second sharpening operation on a second one of the abrasive surfaces using the second guide surface.

Fig. 19 is a schematic representation of the sharpener 600 as viewed from fig. 18 in some embodiments. The sharpener 600 in fig. 19 is characterized as a three (3) stage sharpener, but other configurations may be used as desired.

The drive assembly 606 includes an electric motor 614 that rotates a drive shaft 616 at one or more selected rotational speeds. Three (3) abrasive disks 618A, 618B, and 618C are secured to the shaft 616. Each disk has opposing first and second abrasive surfaces 608A and 608B. It is contemplated that each of the abrasive disks 618A-618C have different levels of abrasiveness such that, for example, disk 618A has a relatively coarse level of abrasiveness, disk 618B has a relatively medium level of abrasiveness, and disk 618C has a relatively fine level of abrasiveness.

The sharpener 600 shown in fig. 19 facilitates a multi-stage sharpening operation to enable a user to sharpen from a coarse sharpening, a medium sharpening, and a fine sharpening in each of three successive sharpening stages or ports, represented at 620A, 620B, and 620C. Fig. 20 provides an isometric view of sharpener 600 of fig. 20 to better illustrate the corresponding sharpening port. Each port includes opposing first and second guide surfaces 610A and 610B.

As further shown in fig. 19, the indicator mechanism 612 includes a series of light emitting devices 622, which may take the form of diodes or other light sources. Control circuitry 604 is configured to selectively activate the various light emitting devices to signal the user to move to a new sharpening position at an appropriate time, such as on the opposite side of a given port (e.g., from surface 610A in sharpening port 620A to surface 610B in sharpening port 620A) or to a new port (e.g., from surface 610A in sharpening port 620A to surface 610A in sharpening port 620B). While a single light emitting device 622 is shown for each port, other configurations, including but not limited to different lights for each sharpening surface, can be readily used.

Although fig. 19-20 show the abrasive surface constituting the abrasive disc surface, the indicator mechanism may be adapted for use with one or more endless abrasive belts. Referring again to the sharpener 300 in fig. 15A and 15B, the abrasive belt 308 provides two moving planar areas or abrasive surfaces that appear adjacent respective sharpening guide slots 314, 316 (see, e.g., fig. 2A). Accordingly, a light emitting device 622 as depicted in fig. 19-20 may be incorporated into sharpener 300 to signal to the user that each side of the knife is sharpened against each of these abrasive surfaces according to the routine of fig. 16.

When using the same light emitting device as in fig. 19-20, the control circuit may operate the device to provide a change in illumination state to signal that the change occurred. In some cases, a simple off-on sequence may be provided to illuminate the desired location. In other cases, different colors (e.g., red, green, etc.) may be used to signal different indications to the user. Other configurations may include, but are not limited to, the use of a flashing light, a progression of multiple lights, a change in the pulse frequency or duration of a light, etc., to convey information to a user regarding the status of a given sharpening operation.

For example, the change in illuminance may notify the user of the progress of the detected sharpening operation, for example, by detecting or estimating the sharpening level when the user performs the first sharpening operation. The indicator mechanism may provide a countdown sequence, for example, by: the manner in which the lights of a row are continuously turned off as sharpening continues until all lights are turned off and a new row of lights is illuminated, thereby guiding the user to move to a new location and begin a second sharpening operation. These and other alternative configurations will be readily apparent to those skilled in the art in view of this disclosure.

The control circuit 604 may be configured in a variety of ways, including as discussed above in fig. 12-14. Fig. 21 illustrates aspects of the control circuit 604 in some embodiments. The control circuit 604 includes a timer 630 that operates to indicate a predetermined elapsed period of time in response to the timer incrementing or decrementing to a desired value. The monitoring circuit 632 may monitor the progress of the timer 630 and at the end of each interval, signal an indicator mechanism to guide the user to a new sharpening position.

Another configuration for the control circuit 604 is shown in fig. 22. In this case, the one or more sensors 634 operate to sense the presence of the cutting tool (e.g., knife) adjacent the first guide surface. The counter circuit 636 provides an incremented count based on the detected event from the sensor 634. As before, the monitoring circuit 638 monitors these respective components to determine that the first sharpening operation has successfully ended, after which the monitoring circuit signals the indicator mechanism as before.

In some cases, sensor 634 may represent a plurality of sensors that operate to sense sharpening operations. Examples include proximity sensors, resistance sensors, motor load current sensors, and the like. It is contemplated that the sensor will have sufficient sensitivity and resolution to detect each of a series of sharpened wipes as the user repeatedly presents the cutting edge of the tool on the first abrasive surface, and the counter 636 will increment the total count of each wipe. Other arrangements are contemplated, including using a motor load current sensor to identify which abrasive disc (or other abrasive media) is being used, to assess the relative sharpness of the cutting edge in response to changes in motor load current over time, and so forth.

Fig. 23 provides another sharpener 640 according to a further embodiment. Sharpener 640 is similar to sharpener 600 in fig. 18, and like reference numerals are used for like components. The schematic depiction of fig. 23 shows that the sharpener 640 is a dual stage sharpener having two sharpening ports 620A, 620B with double sided abrasive discs 618A and 618B.

The indicator mechanism 612 in fig. 23 provides an indication to the user for the sharpening position using the actuator 642 and the movable cover 644. The actuator may take the form of a solenoid, spring, or the like adapted to controllably advance and retract the cap adjacent the respective sharpening ports 620A and 620B. While the cover is shown in fig. 23 as being laterally translatable (e.g., slidable left and right), other cover configurations are readily contemplated, including covers that rotate, open, retract, etc., in any suitable direction.

Fig. 24A and 24B illustrate front views of sharpener 640 in some embodiments. During operation, the indicator mechanism 612 operates to expose a first selected one of the sharpening ports (in this case 620A in fig. 24A), which enables a sharpening operation using one or both of the guide surfaces 610A and 610B. First sharpening port 620A is exposed by advancing cap 644 to the right as shown in FIG. 24A.

Indicator mechanism 612 then moves cap 644 to the left to simultaneously cover first sharpened port 620A and expose second sharpened port 620B, as shown in fig. 24B. This configuration guides the user to continue to sharpen against one or both of the surfaces 610A, 610B in the second port 620B.

The indicator mechanism 612 may also incorporate other user-directed indicators, including the light-emitting devices 622 discussed above. For example, a sharpening sequence may include moving the cap 644 to the position in fig. 24A, then turning on the first light emitting device 622A to direct the use of the guide surface 610A in the port 620A. The first light emitting device can then be turned off, and then the second light emitting device 622B can be turned on to direct the use of the surface 610B in the port 620A. Once completed, the cover 644 may be advanced to the position in fig. 24B, repeating the foregoing operations using the third light emitting device 622C and the fourth light emitting devices 622D to guide the user to use the guide surfaces 610A and 610B in the port 620B, respectively.

Fig. 25 shows another sharpener 650 according to a further embodiment. Sharpener 650 is similar to sharpener 640 and like reference numerals will denote like components as previously described. The sharpener 650 is also characterized as a two-port sharpener having two abrasive discs 618A, 618B to support, for example, a coarse sharpening operation and a fine sharpening operation against the two abrasive discs, respectively.

In fig. 25, only a single sharpening port 622 and a single set of opposing sharpened guide surfaces 610A, 610B are provided. This is because the indicator mechanism 612 operates to cause relative movement and alignment of the guide surfaces 610A, 610B with each of the respective abrasive discs 618A, 618B in turn.

As configured in fig. 25, when the indicator mechanism 612 is operated, e.g., via the actuator 652, chuck 654 and spring 656, to align the disks 618A, 618B with the guide surfaces 610A, 610B, respectively, the guide surfaces remain stationary relative to the housing (body) 602 of the sharpener 650. In this manner, once the first sharpening operation is completed using first disk 618A, control circuit 604 advances second disk 618b via the indicator mechanism to guide the user to begin the second sharpening operation.

In an alternative embodiment, the drive assembly 606 may be configured to hold the disks 618A, 618B in a stationary translational relationship with the housing (body) 602, and the sharpening port 622 (having surfaces 610A, 610B) moves from a position adjacent the first disk 618A to a position adjacent the second disk 618B. This alternative configuration is depicted in fig. 26A and 26B, where the cap member 658 of the indicator mechanism slides laterally between these two positions as shown.

Fig. 27 is a functional diagram of yet another power sharpener 660 according to a further embodiment. Sharpener 660 is similar to the sharpener discussed above, and the same reference numerals are used for the same components of sharpener 660. The control circuit 604 receives an activation signal from a power switch, such as 624 (see fig. 20), to power up the sharpener in response to user activation of the switch. The control circuitry directs the drive assembly 606 to initiate movement of the various abrasive surfaces 608 at the appropriate speed. Sensor 662, as described above, is activated to enable the control circuitry to detect and monitor the sharpening sequence.

The indicator mechanism 612 may take any number of suitable forms sufficient to guide the user to the various sharpening guide surfaces and abrasive surface combinations during a sharpening sequence. Additional configurations for the indicator mechanism can include, but are not limited to, the use of a graphical display 664 that provides a visual indication to the user, an audible speaker system 666 that provides an audible indication to the user, and a vibration mechanism 668 that provides a tactile indication to the user by providing a vibration to a handle or other portion of the sharpener housing.

In some cases, the graphical display 664 may be integrated into the sharpener housing at a suitable location for viewing by a user, such as the forward facing surface of the housing. An example is provided again with reference to fig. 24A, where a dashed box 664 represents the integrated graphical display adjacent to the sharpened ports 620A, 620B. It should be understood that the graphical display may provide human-visible characters, instructions, animations, charts, etc. as needed to guide the user through the sharpening sequence. Any number of graphical displays may be used, including LEDs, LCDs, electronic paper, multi-color displays, single color displays, and the like. With reference to the configuration of fig. 24A, it should be understood that the display 664 can be used in place of, or in addition to, other indicator mechanisms, such as the light emitting devices 622A, 622B and the cover 644. It is also understood that the graphical display may be characterized as a light emitting device, depending on its configuration.

In other cases, a separate software application (app) may be downloaded to execute on a smartphone, tablet, or other network accessible device that communicates with the sharpener over a wireless connection using communications (RX/TX) circuitry 670. The application may be configured to provide user control to sharpener 660, which enables a user to remotely power up the sharpener, set various sharpening parameters, enter the type or style of tool to be sharpened, and the like. Likewise, the application may in turn provide user instructions to the user during the sharpening sequence similar to that described above for the integrated display. In some cases, an optional docking station 672 may be provided to enable a user to rest the device in place adjacent to the sharpening port during sharpening. An example of a docking station 672 is shown via a dashed line in fig. 24B. In any event, therefore, one or more indicator mechanisms may be disposed adjacent to the respective first and second abrasive surfaces to enable a user to progress from a first sharpening operation to a second sharpening operation at an appropriate time depending on the indication provided by the indicator mechanism.

Fig. 28 provides a sequence diagram 680 to summarize the foregoing discussion. It will be appreciated that the diagram 680 is similar in some respects to the previous routines discussed above (including fig. 16-17) and may represent programming performed by one or more processors of the control circuit 604 when a programmable processor is used.

Diagram 680 begins at block 682 where the sharpener is initially powered up, which may be performed using a manual power switch, remote activation, sensed activation based on sensed presence of a tool or user, etc. at block 682. As part of the initialization process, the control circuit 604 continues to direct the drive assembly 606 to activate the motion of the first abrasive surface (block 684). It is noted that all abrasive surfaces may be activated simultaneously or individually, as desired. One of a plurality of available speeds may be selected.

Block 686 illustrates operation of the control circuit 604 to direct the indicator mechanism 612, however configured differently as described above, to direct a user to sharpen a preferred tool against the moving first abrasive surface during a First Sharpening Operation (FSO). As described above, the control circuit monitors and detects the end (termination) of the FSO using the one or more sensors 662 (block 688).

The second abrasive material is shown as being activated by block 690 at the end of block 688. In some cases, this is an optional operation because the second abrasive material may already be moving at the desired speed as a result of the operation of block 684. However, in some cases, the second abrasive surface may remain stationary until needed, and activation of the second abrasive surface may operate as at least a portion of an indicator mechanism. In other cases, the change in speed may be performed at block 690, such as reducing the speed to a slower speed.

The control circuit 604 continues to direct the user to perform a Second Sharpening Operation (SSO) using the second abrasive surface via the indicator mechanism at block 692. The SSO is monitored and the end of the SSO is detected as previously described, as shown in block 694.

While the sequence in fig. 28 ends at this point, it should be understood that further sharpening operations may be performed by the sequence, including returning to the first abrasive surface (at the same speed or at a reduced speed), proceeding to a third abrasive surface in a new sharpening port, and so on.

The use of an indicator mechanism as variously described herein advantageously enables an associated sharpener to guide a user through a new sharpening combination of an abrasive surface and a guide surface at the appropriate time. The system may rotate or otherwise advance the first and second abrasive surfaces at the same speed or at different speeds as described above. Similarly, as described above, the first abrasive surface and the second abrasive surface may provide the same or different material release rates. Any number of different configurations of the indicator mechanism and combinations of indicator mechanisms (as desired) will be readily apparent to those skilled in the art in view of this disclosure.

Accordingly, some of the foregoing embodiments may be characterized as involving a single stage power sharpener having a movable abrasive surface adapted for multi-stage sharpening on a cutting tool. The system may include a relatively rough abrasive surface (e.g., having a particle size value of 80 to 200), a pair of opposing guides, and a drive system for the abrasive surface having respective first and second speeds to achieve different first and second material removal rates. In some embodiments, the second velocity of the material (measured relative to the associated guide) may be any suitable velocity, such as less than or equal to about 500 surface feet per minute. The first speed is greater than the second speed, such as greater than or equal to about two (2) times the second speed. Other suitable speed ratios may be used.

The dual speed sharpening process may include placing a blade of a cutting tool to be sharpened into the first guide against the first guide surface and the first edge stop. The first guide surface may extend at a selected bevel angle and the first blade stop may be disposed at a selected distance from the abrasive surface. The abrasive surface can be controlled to advance at a first speed. The blade is pulled across the abrasive surface a number of consecutive times as needed to remove material from the blade and impart a selected beveled surface on the first side of the blade. It is envisaged that this first operation will also produce a burr on the opposite second side of the blade.

The blade may be placed into the second guide against the second guide surface and the second edge stop. The second guide surface may extend at a selected bevel angle and the second edge stop may be a selected distance from the abrasive surface. The abrasive surface is controlled to advance at a second, lower speed. The user pulls the blade across the abrasive surface as many times in succession as necessary to remove material from the blade to remove the burr and achieve the final geometry.

The aforementioned optional parameters may include a first guide and a second guide, which may be the same guide or different guides. If the first guide and the second guide are the same guide, the blades are inserted in different orientations such that the first side is presented on the abrasive surface in a first orientation and the second side is presented in a second orientation at the same bevel angle. This may be accomplished, for example, by flipping the handle of the tool end-to-end to reverse the direction of the blade through the guide.

Where the first and second guides are different guides, the guides may be placed on opposite sides of the abrasive material, and the blade inserted into the first guide at a first bevel angle relative to the abrasive surface, and the blade subsequently inserted into the second guide at a second bevel angle. The first and second ramp angles may be the same and may, for example, extend in a range from about 10 degrees to about 25 degrees.

As described above, one or more abrasive surfaces may extend on a flexible belt that travels along a path having two or more rollers, one of which is driven by a drive system having an electric motor. Alternatively, the one or more abrasive surfaces may extend over one or more flexible discs driven by an electric motor.

Each abrasive surface may be spring biased to enable each abrasive surface to apply a selected force to the blade when the blade inserted against the first guide or the second guide is displaced. In each case, the force between the blade and the surface in the first guide is equal to the force in the second guide, or greater than the force in the second guide. In some cases, the abrasive surface is a flexible belt and the spring bias on the belt is between about 2 pounds and 12 pounds. Deflection of the abrasive surface away from the medial plane may occur in a range of about 0.04 inches to about 0.25 inches.

In view of this disclosure, those skilled in the art will recognize that the flexibility of the associated media (e.g., flexible disk, flexible belt) provides different surface pressures to the associated cutting tool based on changes in the velocity of the abrasive material. It is believed that faster abrasive material speeds may generally tend to impart greater inertial and/or structural rigidity to the media (e.g., via centrifugal forces), thereby achieving greater material removal rates at faster media speeds. The slower speed of the media is typically selected to be fast enough to remove any burrs, but slow enough not to significantly change the geometry of the blade. The actual speed will depend on a variety of factors (including different blade geometries, levels of abrasiveness, abrasive member stiffness and mass, etc.) and may be determined empirically. A plurality of available speeds may be provided for the sharpener and the user selects the appropriate speed based on various factors. A final honing stage, such as an abrasive bar or other fixed abrasive member, may further be provided to provide final honing of the final cutting edge.

Further embodiments of the present disclosure may also be characterized as a power sharpener having at least two sharpening positions with a guide surface and an abrasive surface combined to facilitate a first sharpening operation and a second sharpening operation. The user-guided indicator mechanism is operable to guide the user to begin a second sharpening operation at the end of the first sharpening operation. The indicator mechanism may be operable to direct each sharpening operation in turn, as desired, to provide the user with an efficient and effective sharpening sequence.

It is to be understood that even though numerous characteristics and advantages of various embodiments of the present disclosure have been set forth in the foregoing description, together with details of the structure and function of various embodiments, this detailed description is illustrative only, and changes may be made in detail, especially in matters of structure and arrangement of parts within the principles of the present disclosure to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.