Patent Application
20150343590
Cutting tools are used in a variety of applications to cut or otherwise remove material from a workpiece. A variety of cutting tools are well known in the art, including but not limited to knives, scissors, shears, blades, chisels, spades, machetes, saws, drill bits, etc.
A cutting tool often has one or more laterally extending, straight or curvilinear cutting edges along which pressure is applied to make a cut. The cutting edge is often defined along the intersection of opposing surfaces that intersect along a line that lies along the cutting edge.
Cutting tools can become dull over time after extended use. It can thus be desirable to subject a dulled cutting tool to a sharpening operation to restore the cutting edge to a greater level of sharpness. A variety of sharpening techniques are known in the art, including the use of grinding wheels, whet stones, abrasive cloths, etc. While these and other sharpening techniques have been found operable, there is a continued need for improvements in the manner in which various cutting tools may be sharpened.
Various embodiments of the present disclosure are generally directed to an apparatus for sharpening a cutting edge of a tool.
In some embodiments, a tool sharpener is provided with an abrasive medium having an abrasive surface. A stationary tool support guide has a guide surface that extends along a guide plane at a selected angle with respect to the abrasive surface. The guide surface contactingly supports a side of the tool during presentation of a cutting edge of the tool against the abrasive surface. A rotatable edge guide adjacent the stationary tool support guide has a roller member with a curvilinearly extending outer surface. The roller member is rotatable about an edge guide roller axis and is moveable between a deployed position and a retracted position. In the deployed position, the roller member is positioned to contactingly engage the cutting edge during the presentation of the cutting edge against the abrasive surface. In the retracted position, the roller member is positioned to provide a non-contacting clearing relation with the cutting edge during said presentation.
In related embodiments, the tool sharpener has a base structure which encloses an electric motor. An abrasive medium is supported by the base structure and adapted for rotational movement responsive to the electric motor, the abrasive medium having an abrasive surface extending along a neutral plane. A stationary tool support guide has a guide surface extending along a guide plane at a selected angle with respect to the neutral plane to engage, via sliding contact, a side of the tool during presentation of a cutting edge of the tool against the abrasive surface. A rotatable edge guide adjacent the stationary tool support guide has a roller member having a curvilinearly extending outer surface rotatable about an edge guide roller axis. The rotatable edge guide is rotatable about an edge guide central axis between a deployed position and a retracted position. In the deployed position, the roller member is a first distance from the guide surface to facilitate rolling support of the cutting edge during said presentation. In the retracted position, the roller member is a second distance from the guide surface greater than the first distance to provide a non-contacting, clearing relation with the cutting edge during said presentation.
In further related embodiments, the tool sharpener has an endless abrasive belt with an abrasive surface. The belt is over a belt roller and placed under tension to present a planar extent of the belt adjacent the roller, the roller rotatable about a first axis. A stationary tool support guide has a guide surface extending along a guide plane at a selected angle with respect to the planar extent of the belt to engage, via sliding contact, a side of the tool during presentation of a cutting edge of the tool against the abrasive surface of the belt. A rotatable edge guide adjacent the stationary tool support guide includes a roller member having a curvilinearly extending outer surface rotatable about a second axis orthogonal to the first axis to engage, via rolling contact, the cutting edge during said presentation of the cutting edge against the abrasive surface.
These and other aspects of various embodiments of the present disclosure will become apparent from a review of the following detailed description in conjunction with the accompanying drawings.
The tool sharpener 100 includes a base structure 102 which encloses and/or supports various components of interest. The structure 102 includes a main body 104 and a sharpening attachment assembly 106. The sharpening attachment assembly 106 can be removably mated with the main body 104 to facilitate various sharpening operations described below. As desired, other operable attachments (not separately shown) can be installed on the main body 104 to carry out other motor-driven functions.
The main body 104 is adapted to be securely placed on a base surface 108 (
The motor is used to drive an abrasive member 114 during a sharpening operation. The abrasive member 114 is characterized as an endless abrasive belt which is routed along a belt path that passes adjacent rollers 116A, 116B and 116C. Other forms of abrasive members can be used in accordance with the present disclosure, including disc shaped abrasive members, non-motor driven abrasive members, etc. It will be noted that the abrasive belt 114 is supported by, and is located outside of, the base structure 102 to expose various portions of the belt for sharpening operations and to facilitate easy removal and replacement of the belt.
A spring-biased tensioner assembly 118 coupled to roller 116C applies a tension force to the abrasive member (hereinafter, “belt”) 114. This forms two planar extents 114A, 114B that extend between rollers 116A-116B and 116A-116C, respectively. The planar extents 114A, 114B are best viewed in
An adjustable sharpening guide assembly 120 is provisioned adjacent the planar extents 114A, 114B. The sharpening guide assembly 120 includes a pair of opposing, stationary sharpening guides 122A, 122B. The stationary sharpening guides 122A, 122B have respective guide surfaces 124A, 124B which extend along respective guide planes at a common, fixed acute angle with respect to the neutral planes of the planar extents 114A, 114B.
The guide surfaces 124A, 124B contactingly support the respective side surfaces of a cutting tool during a double-sided sharpening operation as the cutting tool is presented against each guide surface in turn. A cam-based adjustment mechanism can be used to selectively set the guide surfaces 124A, 124B to the common, fixed acute angle. Angles from about 15 degrees to about 30 degrees can be selected.
A rotatable edge guide is represented generally at 130. As further shown in
It is contemplated that the roller members 136A, 136B are formed of a suitable compliant material, such as a non-marring plastic. The use of a compliant material will tend provide a desired level of friction between the roller member and the cutting edge to ensure rotational movement of the roller is established during retraction of the tool. However, other materials can be used including rigid materials such as metal for the roller members.
Shaft fasteners 138A, 138B secure the roller members 136A, 136B to the central body 134 and facilitate independent rotation of the roller members about an edge roller guide axis 140.
The central body 134 is secured to the plate 132 using shaft fastener 142. A biasing member (e.g., coiled spring) 144 exerts a biasing force upon the central body 134 to urge the central body in a direction toward the plate 132. The shaft fastener 142 and biasing member 144 facilitate selective rotation of the central body 134 about an edge guide central axis 146 between the deployed position (
It will be noted that the edge guide roller axis 140 is orthogonal to the edge guide central axis 146 irrespective of the rotational position of the central body 134, but this is merely exemplary and not necessarily limiting. It will further be noted that, in the deployed position, the edge guide roller axis 140 is orthogonal to the roller axes about which each of the belt rollers 116A, 116B, 116C rotate. In the retracted position, however, the edge guide roller axis 140 is non-orthogonal (skewed) to these roller axes.
Referring again to
When moved to the retracted position, the roller members 136A, 136B are positioned to provide a non-contacting clearing relation with the cutting edge of the tool during such sharpening operations. The retracted position provides clearance for finger guards or other features that would otherwise mechanically interfere with the presentation of the cutting tool against the abrasive member. It will be noted that at least roller member 136A is a first distance from the corresponding guide member 122A in the deployed position and a second, greater distance from the guide member 122A in the retracted position.
At this point it will be noted that the edge guide 130 is referred to herein as “rotatable” due to the rotating nature of the roller supports supplied in the deployed position, not necessarily because the edge guide 130 can be rotated between the deployed and retracted positions. Other translational movement paths, including non-rotational paths (e.g., linear paths, etc.), can be used to transition the rotatable edge guide 130 between the deployed and retracted positions.
A transition sequence is illustrated in
Initially, as shown in
The user next rotates the central body 134 about the central axis 146 (
Finally, as shown in
A cutting edge 178 extends along the length of the blade portion 174 and is defined along the converging intersection of the opposing side surfaces. A top surface 180 is provided opposite the cutting edge 178. The top surface 180 remains non-contactingly supported during sharpening using the sharpener 100, thereby providing clearance to permit a wide variety of sizes and shapes of tools to be sharpened, as well as accommodating rotational retractional movement of the knife 170 during sharpening, as will now be described.
To begin the sharpening sequence, as depicted in
Concurrently, the knife 130 is rotated about its longitudinal axis (e.g., length from end of handle to end of blade) as required to bring a portion of the side surface 176 into contacting planar alignment with the guide surface 124B. The abrasive member 114 can be rotating along its associated belt path during this insertion phase or rotation can be subsequently initiated by the user.
Once aligned, the cutting edge 178 contactingly engages the planar extent 114A of the abrasive member 114 and relative movement of the abrasive surface adjacent the tool will induce sharpening of the cutting edge. Some deflection of the abrasive member 114 may occur during such contact, as will be explained below.
As shown by
The rolling contact provided by the rotatable edge guide 130 reduces the propensity for the associate roller member to dull that portion of the cutting edge that has already been presented against the abrasive surface. It will be noted that the stationary edge guide 182 can also be configured as a rolling guide as desired.
As further shown by
More particularly, the configuration of
As shown in greater detail in
As noted above, the translational movement of the rotatable edge guide 130, 130A disclosed herein allows a wide variety of different types and styles of cutting tools to be sharpened using the tool sharpener 100.
In this way, a constant and consistent grinding plane can be maintained with respect to the blade material and shape. A first amount of torsion in a generally counter-clockwise direction occurs near the handle 232 as shown by
When alternately applied to opposing sides of the blade 252, the first abrasive medium 114-1 provides continuously extending, substantially convex surfaces along sides 254, 256 which converge and intersect to form the cutting edge 258. The first abrasive medium 114-1 is characterized as an endless abrasive belt having a relatively coarse abrasive level, and relatively high linear stiffness characteristics.
It is contemplated in some embodiments that sharpening operations can be carried out as discussed above using a first belt such as 114-1 to provide a coarse grinding operation, followed by replacement of the first belt with a second belt such as 114-2 to provide a fine grinding (honing) operation. The rotatable edge guide 130 and stationary guide assembly 120 can be used to provide support during these and other types of sharpening operations.
While various embodiments set forth above have provided rotatable edge guide arrangements in the context of an endless abrasive belt, the arrangements can further be adapted for other forms of abrasive media, such as but not limited to rotatable abrasive disks.
As explained below, the tool sharpener 300 is adapted to sharpen a wide variety of different styles and types of cutting tools using a sequence of sharpening stations, each adapted to accommodate a different type of sharpening operation. In some embodiments, the stations can be used to provide multi-stage sharpening as discussed above in
In other embodiments, the stations can be used to accommodate sharpening operations on different types of tools requiring different presentation angles, such as kitchen knives and scissors, etc. Regardless, the various operational features discussed above for the tool sharpener 100 are incorporated and adapted into the tool sharpener 300, as will now be explained.
The tool sharpener 300 includes a base structure 302 which encloses and/or supports various features of interest, including an electrical motor (not separately shown) to provide motive power during the sharpening operation. A user activated switch 304 can be used to selectively activate the powered operation of the sharpener.
A number of abrasive members, in this case three (3), are shown at 306, 308 and 310. The abrasive members 306, 308, 310 are supported within the interior of the base structure 302 and are respectively characterized as rotatable abrasive disks with abrasive surfaces supplied on opposing sides thereof. It is contemplated that the abrasive surfaces each have respective planar extents that extend along a neutral plane during operation of the sharpener 300 to accommodate the presentation of the cutting edge of a tool during a sharpening operation. The abrasive surfaces may have a common abrasiveness level, or may be different from one disk to the next.
The abrasive disks can be formed of any suitable material and may be rigid, axially deflectable and/or radially deformable. In some embodiments the disks are flexible (“floppy”) so that, when at rest, the flexible disks rest in a somewhat deformed, bent and/or quasi-folded position due to the force of gravity. Once rotation is initiated, however, the disks quickly transition to the aforementioned neutral plane due to centripedal forces induced by disk rotation. The use of flexible disks may impart similar deformation modes as discussed above in
As noted above, each disk 306, 308, 310 forms a portion of a separate sharpening station 312, 314 and 316, with each sharpening station accommodating double sided sharpening. Detailed aspects of the sharpening station 312 are generally depicted in
As shown in
As with the guide assembly 120 discussed above, the guide assembly 320 can be configured to be adjustable to selectively set the guide surfaces 324A, 324B to a selected common fixed angle. However, in other embodiments the angle of each station is not adjustable. The angle of each station may vary from one station to the next. For example, station 312 may be set at nominally 20 degrees, station 314 may be set at nominally 25 degrees, and station 316 may be set at nominally 40 degrees. Other respective values can be used as desired.
Referring again to
As before, the roller member 332 is formed of a compliant material to enhance rolling contact between the roller member 332 and the cutting tool during a sharpening operation. The rotatable edge guide 330 is further configured for rotation about an edge guide central axis established by a pivot member 342 secured to the base structure 302. A biasing member (e.g., coiled spring) 344 supplies a biasing force upon the central body 334.
In this way, as shown in
It will be noted that the edge roller axis 340 is nominally parallel to the axis of rotation of the disks 306, 308 and 310, and is also nominally parallel to the edge guide central axis of pivot 342, during all positional modes. The roller member 332 is a first distance from the respective guide members (e.g., 332A, 332B) in the deployed position and a second, greater distance from the respective guide members in the retracted position.
In a manner similar to the sharpening operations discussed above, the user inserts the knife 350 into the appropriate slot and brings a portion of the side surface 356 into contacting engagement with the associated guide surface (such as guide surface 324B in
It will now be appreciated that the various embodiments presented herein provide a number of benefits over the art. The use of a rotating edge guide advantageously provides mechanical support, via rolling non-dulling contact, the cutting edge during a sharpening operation. The edge guide allows precise location of the cutting tool relative to the abrasive member over repeated sharpening passes. The translational aspects of the edge guide further allow the roller to be fully retracted out of the way as needed, and in some cases, partially deflected to accommodate guard projections and other features that would otherwise tend to interfere with the sharpening process.
While motor-driven powered sharpeners have been disclosed herein, such is merely exemplary and is not limiting. Any number of different types of sharpener configurations can employ the various features exemplified herein, including sharpeners that do not employ a motor-driven abrasive surface.
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 thereof, this detailed description is illustrative only, and changes may be made in detail, especially in matters of structure and arrangements 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.
