Title:
POCKET SHARPENER FOR KNIVES
Kind Code:
A1


Abstract:
A blade sharpening tool adapted for hand-held use, comprising two mating housing components and two bits wherein the bits can be of tungsten carbide material. Each mating housing component can comprise a plurality of integrated fastening elements. The mating housing components can be secured together by engaging integrated fastening elements, thereby securing the bits. The bits can thereby form a specified gap angle favorable for a blade-sharpening process. The integrated fastening elements can be of a snap fit cantilever beam design. Alignment posts can extend into and/or through the bits.



Inventors:
Sterngold, Bonnie (Portola Valley, CA, US)
Application Number:
11/852242
Publication Date:
03/12/2009
Filing Date:
09/07/2007
Primary Class:
International Classes:
B24D15/08
View Patent Images:



Primary Examiner:
WILSON, LEE D
Attorney, Agent or Firm:
WEST & ASSOCIATES, A PC (WALNUT CREEK, CA, US)
Claims:
What is claimed is:

1. A blade sharpening tool comprising: a first and a second mating housing component; a first and a second bit; a plurality of first fastening elements integrated with the first mating housing component; a plurality of second fastening elements integrated with the second mating housing component; wherein the first and second mating housing components are secured together by engagement of the plurality of first fastening elements with the plurality of second fastening elements, thereby securing the first and second bits.

2. An apparatus according to claim 1 further comprising: a first channel in the first mating housing component; a second channel in the second mating housing component; a first bit-alignment post integrated with the first mating housing component and located within the first channel; a second bit-alignment post integrated with the second mating housing component and located within the second channel; wherein a first hole extends into the first bit, the first hole having a first geometry sufficient to accept the first bit-alignment post; wherein a second hole extends into the second bit, the second hole having a second geometry sufficient to accept the second bit-alignment post; and wherein the first bit is located constrained within the first channel and the second bit is located constrained within the second channel, the bits thereby forming a specified gap angle.

3. An apparatus according to claim 1 wherein the first and second bits are of tungsten carbide material.

4. An apparatus according to claim 1 wherein a first fastening element of the first plurality of fastening elements and a second fastening element of the second plurality of fastening elements are of a cantilever beam design, and are interengaged.

5. An apparatus according to claim 2 wherein the first and second bits are of tungsten carbide material.

6. An apparatus according to claim 2 wherein a first fastening element of the first plurality of fastening elements and a second fastening element of the second plurality of fastening elements are of a cantilever beam design, and are interengaged.

7. An apparatus according to claim 2 wherein: the first hole extends through the first bit; and a third hole extends into the second mating housing component, the third hole having a third geometry sufficient to accept the first bit-alignment post.

Description:

BACKGROUND

1. Field of the Invention

The present invention relates to hand-held knife sharpeners and more particularly to a device for sharpening cutlery, particularly cutlery having a blade that tapers to a thin edge.

2. Description of the Related Art

There are a variety of devices for sharpening cutlery, including: grinding wheels, sharpening stones, files, and specialized edge stripping devices for blades having a tapered edge. Strip sharpeners such as that disclosed in U.S. Pat. No. 4,624,157 “Pocket Sharpener for Knives” can operate longitudinally along the edge of a blade and can simultaneously shave both sides of a tapered blade edge. Relative to other devices and methods, the use of a strip sharpener can provide a specified optimum angle of taper to a blade edge. The requirements of a strip sharpening process allow for a compact tool design, and, for hand-held use.

Many extant strip-sharpening tool designs provide for fixedly securing a pair of bits, thereby forming a specified gap angle. In some tools the bits are secured by screws engaged with a common supporting structure which can be a simple cylindrical rod. Screws can become loose over time. In other tools the bits are fixedly secured within one or more housing components and the housing components and/or bits themselves secured together in a variety of ways. The housing components and/or bits are typically secured together by means of screws, rivets, and/or adhesives. In some cases, plastic housing components can be joined by sonic welds. Although such exemplary approaches to securing an assembly together can be effective, they also add cost and/or complication in manufacturing. Such approaches require additional parts and/or additional assembly operations and/or additional material and/or the use of specialized materials.

What is needed is a strip-sharpening tool that can be easily assembled from a relatively small number of parts, and with a minimum of assembly operations and/or other costs of manufacture.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 depicts an embodiment of a blade-sharpening tool.

FIG. 2 depicts a sharpening process employing a blade-sharpening tool.

FIG. 3 depicts an embodiment of a blade-sharpening tool in an exploded axonometric view.

FIGS. 4A, 4B, 4C depict an exemplary cantilever beam design for snap-fit connection.

DETAILED DESCRIPTION

FIG. 1 illustrates an embodiment of a blade sharpening tool 100. The tool comprises a first bit 101, a second bit 102, a first mating housing component 103, and a second mating housing component 104. The bits 101 102 can extend into and can be secured, within the assembly. In some embodiments, the bits 101, 102 can be fixed. In alternate embodiments, the bits can be pivotably, rotatably and/or rotatably coupled with the first and/or second mating housing components 103, 104. Each bit 101 102 can be essentially box-shaped, that is, essentially a cuboid or rectangular prism. In some embodiments, the bits can be ovoid or elliptical and/or have any other known and/or convenient geometric properties such that at a prescribed location the intersection of at least two surfaces of the bits can form a predetermined gap angle 105.

A gap angle 105 can be specified, corresponding to a converging and overlapping arrangement of the bits 101 102. The gap angle 105 is the angle between planes that essentially include the designated faces 107 108. In some embodiments the gap angle can be specified as about 40 degrees However, in alternate embodiments the bits 101 102 can be geometrically configured to form a gap angle 105 that can have any predetermined angle or a variable angle based upon the geometry of the individual bits 101 102.

FIG. 2 illustrates a sharpening process employing an embodiment of the tool 100. A tapered or to-be-tapered blade edge can be positioned against the bits 101 102 and drawn along the designated path 201 in the indicated direction. As the blade edge remains in contact with and moves across the bits 101 102, blade material can be reshaped and/or removed by the action of the bits upon the blade. Blade material can be removed in strips due to this action, hence the designation of “strip sharpener” for such an embodiment.

The bits 101 102 can be fabricated of tungsten carbide material and/or other known and/or convenient material having properties suitable for sharpening a blade comprised of a known material. In some embodiments tungsten carbide bits, having a predetermined relative hardness, can be effective in sharpening a variety of blades fabricated of steel and/or other materials and that span a prescribed range of relative hardnesses from 1-10 on the Mohs scale or an absolute hardness in any prescribed range between 1 and 1500 on the absolute hardness scale.

In the orientation shown, a tool embodiment 100 can be conveniently held and/or stabilized by an operator's left hand while the operator's right hand holds the knife or other cutlery and draws its blade along the designated path 201 in contact with the bits. The operator's left hand can be positioned at some distance from the blade and bits due to the length of the tool, enhancing safety of operation. It can be appreciated that a simple inversion of tool position results in a convenient complementary orientation wherein an operator's left hand can similarly hold and move the knife or other cutlery while the operator's right hand holds and/or stabilizes the tool 100.

FIG. 3 is an exploded axonometric view of an embodiment of a blade sharpening tool 100. The tool comprises a first bit 101, a second bit 102, a first mating housing component 103, and a second mating housing component 104.

The first mating housing component 103 can comprise a plurality of integrated first fastening elements 301. The second mating housing component 104 can comprise a plurality of integrated second fastening elements 302. In assembly of the tool 100, the first and second mating housing components 103 104 can be secured together by the interengagement of the first fastening elements 301 with the second fastening elements 302. The fastening elements can be of a snap-fit type design. In some embodiments the fastening elements can comprise members of a cantilever beam snap-fit design. In an illustrated embodiment 100 the first fastening elements 301 can be cantilever beam members, and the second fastening elements 302 can be cantilever beam-receiving members, of a snap-fit design. In alternate embodiments, the first housing component 103 and the second housing component 104 can have any known and or convenient shape and can be selectively coupled using any known and/or convenient mechanism. In some embodiments, the housings 103 104 can be configured such that the housing can be selectively coupled and de-coupled, such that one or more of the bits 101 102 can be replaced. However, in alternate embodiments, the housings can be configured such that once coupled they cannot be de-coupled without damage to one or more of the housings 103 104.

In some embodiments the mating housing components 103 104 and/or other integrated design features can be fabricated of molded plastic and/or fabricated in an injection-molding process and/or fabricated of high-impact polystyrene, and/or any other known and/or convenient material

The first mating housing component 103 comprises a first channel 303, which can be integrally formed. A first bit-alignment post 305 is integrated with a first mating housing component 103. The first bit-alignment post 305 extends vertically as depicted in FIG. 3 from the floor 307 of the first channel 303, along an axis essentially orthogonal to a horizontal plane essentially of that floor. In some embodiments the first bit-alignment post 305 can be of cylindrical shape. However, in alternate embodiments the alignment post 305 can have any known and/or convenient geometric properties and/or in some configurations may not be present. The first channel 303 has a geometry sufficient to accept a first bit 101. A first hole 309 in the first bit 101 has a geometry sufficient to accept the first bit-alignment post 305. The vertical depth of the first channel 303 can be essentially equal to the vertical depth of the first bit 101 as depicted in FIG. 3.

A complimentary second mating housing component 104 comprises a second channel 304, which can be integrally formed. A second bit-alignment post 306 is integrated with a second mating housing component 104. The second bit-alignment post 306 extends vertically as depicted in FIG. 3 from the floor 308 of the second channel 304, along an axis essentially orthogonal to a horizontal plane essentially of that floor. In some embodiments the second bit-alignment post 306 can be of cylindrical shape. However, in alternate embodiments the alignment post 306 can have any known and/or convenient geometric properties and/or in some configurations may not be present. The second channel 304 has a geometry sufficient to accept a second bit 102. A second hole 310 in the second bit 102 has a geometry sufficient to accept the second bit-alignment post 306. The vertical depth of the second channel 304 can be essentially equal to the vertical extent of the second bit 102 as depicted in FIG. 3. In some embodiments, the first channel 303 and/or second channel 304 can be comprised of one or more guide points, and/or any other convenient mechanism or mechanisms, located within the housing 103 104 such that bit 101 and/or bit 102 are/is substantially restrained from movement in at least one plane.

Each of the bits 101 102 can be essentially box-shaped, that is, essentially a cuboid or rectangular prism. Walls and/or other restraining mechanism bounding each channel 303 304 can constrain position of the each of the respective bits 101 102 within a horizontal plane by closely surrounding some surfaces of the respective bits 101 102 within that plane, as depicted in FIG. 3. Position of each bit 101 102 in a horizontal plane can also be constrained by the respective interlocking holes 309 310 and bit-alignment posts 305 306.

In alternative embodiments each bit-alignment post 305 306 can be of alternative shape. In some embodiments, a horizontal cross-section of a bit-alignment post 305 306 can comprise essentially a triangle, quadrilateral, or other polygon. The horizontal cross-section can alternatively comprise a closed shape comprising essentially non-polygonal features including by way of non-limiting example arcs. An ellipse is an example of a non-polygonal closed shape. A horizontal cross-section that is not circular can beneficially constrain rotational position of a bit 101 102 in a horizontal plane.

In some embodiments a first bit-alignment post 305 can be essentially square in horizontal cross-section. A first hole 309 in the first bit 101 can have a geometry sufficient to accept the square-aspect bit-alignment post. The accepting geometry can comprise a hole with square cross-section configured to engage the post 305. When assembled with the first bit-alignment post 305 interlocked with the first hole 309, rotation and translation of the bit in a horizontal plane can be constrained by interference between the bit-alignment post 305 and the surrounding hole 309.

In some embodiments one or both bit-alignment posts 305 306 can comprise extending edges that are essentially orthogonal to a horizontal plane essentially of a respective channel floor 307 308. In some embodiments, bit-alignment post shapes that are essentially right prisms can be employed to facilitate manufacture. In some embodiments, tooling such as drilling in order to form an accepting geometry of a bit-alignment post 305 306 can be performed in an advantageous direction orthogonal to a surface of a bit 101 102.

In some embodiments of an assembled tool 100, the first bit 101 can be constrained in position along a vertical axis as depicted in FIG. 3. The position of the first bit 101 can be constrained vertically by the floor 307 of the first channel 303 and a surface of the second mating housing component 104. In some embodiments of an assembled tool essentially zero vertical clearance remains after the vertical extent of the first bit 101 between the surrounding channel floor 307 and the second mating housing component 104.

Similarly, in some embodiments of an assembled tool 100, the second bit 102 can be constrained in position along a vertical axis as depicted in FIG. 3. The position of the second bit 102 can be constrained vertically by the floor 308 of the second channel 304 and a surface of the first mating housing component 103. In some embodiments of an assembled tool essentially zero vertical clearance remains after the vertical extent of the second bit 102 between the surrounding channel floor 308 and the first mating housing component 103.

In some embodiments of an assembled tool 100, the first bit-alignment post 305 can extend from the floor 307 of the first channel 303 entirely entirely through the first hole 309 of the first bit 101, and into a third hole 311 within the second mating housing component 104. The third hole 311 can have a geometry sufficient to accept the first bit-alignment post 305.

Similarly, in some embodiments of an assembled tool 100, the second bit-alignment post 306 can extend from the floor 308 of the second channel 304 through the second hole 310 of the second bit 102 and into a fourth hole 312 within the first mating housing component 103. The fourth hole 312 can have a geometry sufficient to accept the second bit-alignment post 306.

In some embodiments a housing alignment post 315 can extend vertically from the second mating housing component 104, as depicted in FIG. 3. The housing alignment post 315 can be integrally formed and/or otherwise integrated with the second mating housing component 104. In some embodiments a housing alignment post receiver 316 can be integrally formed and/or otherwise integrated with the first mating housing component 103. The housing alignment post receiver 316 can have a geometry sufficient to accept the housing alignment post 315. During assembly of the tool 100, the interlocking alignment post 315 and receiver 316 can aid in guiding the mating housing components together by constraining relative (planar) translation of the first and second mating housing components 103 104. The interlocking structure of post 315 and receiver 316 can also aid in maintaining beneficial relative positions of the mating housing components 103 104 in an assembled tool 100.

FIGS. 4A 4B 4C illustrate an exemplary cantilever design for a snap-fit connection, in cross-section. By way of example and not limitation, such a design can be used in embodiments of the integrated fastening elements 301 302. A cantilever beam design can have a cantilever beam member 401 and a cantilever beam-receiving member 402. FIG. 4A depicts beam 401 and beam-receiving member 402 prior to assembly. FIG. 4B depicts beam 401 undergoing deformation as it travels into assembled position. FIG. 4C depicts beam 401 and beam-receiving member 402 in assembled position.

In an assembly process, the cantilever beam member 401 can undergo elastic and/or elasto-plastic deformations as the cantilever beam member 401 and receiving member 402 are forced together into an assembled position. In some embodiments, a cantilever beam and/or other members of a design may return to an essentially undeformed state upon interengaging assembly. In some embodiments, assembled members may remain in a deformed state and thereby provide forces advantageous to the function and/or performance of an assembled tool. By way of example and not limitation, a tool assembly wherein members are held in non-zero tension and/or compression resulting from deformation may thereby have advantageous reduction in vibration and/or relative movement of members and/or other components of the assembled tool, when the tool is used.

It can be appreciated that in some embodiments during assembly and/or thereafter the cantilever beam-receiving member and/or other associated components of a tool can also undergo deformations. These deformations can occur in combination with deformation of the cantilever beam. Such deformations can be considered in design.

For components of a tool that incorporates snap-fit-assembled components, many considerations can contribute to selection and/or specification of dimensions and/or materials and/or assembly and/or manufacturing processes. In the present apparatus, any known and/or convenient mechanism can be employed.

The outer perimeter of each mating housing component can comprise an edge of each housing that remains essentially exposed in an assembled tool 100. In cross-sections 313 314 as depicted in FIG. 3, each outer perimeter can comprise a right angle. In some alternative embodiments, one or both of the outer perimeters can comprise an alternative shape in cross-section. By way of non-limiting examples alternative shapes can include bevels, arcs and/or any known and/or convenient geometry.

In addition to securing by interengagement of the integrated fastener elements 301 302, in some embodiments of the assembled blade-sharpening tool 100 the mating housing components 103 104 and/or bits 101 102 and/or any other parts of the tool can be further secured together by additional means. In some embodiments, these additional means can comprise screws, rivets, adhesives, bands, clamps, sonic welds and/or any other known and/or convenient means of securing an assembly. In some embodiments the interengagment of the housings 103 104 can fixedly secure the housings and/or the bits 101 102 relative to one another. In alternate embodiments, the interengagement of the housing 103 104 can restrict one or more degrees of freedom of the bits 101 102.

In some embodiments typical outer dimensions of an assembled blade-sharpening tool can be approximately 2.9 inches by approximately 0.75 inches by approximately 0.28 inches. In some embodiments typical outer dimensions of bits can be approximately 0.50 inches by approximately 0.25 inches by approximately 0.63 inches. In some embodiments typical dimensions of each of the mating housing components 103 104 can include a typical wall thickness of 0.075 inches. However, in alternate embodiment the blade-sharpening tool can have any convenient dimensions and/or geometric properties.

In the foregoing specification, the embodiments have been described with reference to specific elements thereof. It will, however, be evident that various modifications and changes may be made thereto without departing from the broader spirit and scope of the embodiments. The specification and drawings are, accordingly, to be regarded in an illustrative rather than restrictive sense.