KNIFE SHARPENER

Abstract

A sharpener for sharpening a cutting edge of a cutting tool includes: a housing having an elongated vertically extending slot therein, and an anchor region; and a spring biased sharpening element having a pair of arms, the sharpening element being arranged within the housing and secured to the housing at the anchor region below the vertically extending slot to provide a pivot point for the arms. The sharpening element has: a coil spring portion, arranged at the pivot point, and the pair of arms integrally formed with the coil spring portion, each arm having first and second elongated sharpening portions, respectively, extending from respective ends of the coil spring portion, the coil spring portion and the first and second elongated sharpening portions being spring biased in relation to one another to maintain a crossed relation within housing during a passing through of a cutting edge for sharpening.

Claims

1. A sharpener for sharpening a cutting edge of a cutting tool, comprising: a housing extending in an upright plane having an elongated vertically extending slot therein, and an anchor region; a spring biased sharpening element having a pair of arms, the sharpening element being arranged within the housing and secured to the housing at the anchor region below the vertically extending slot to provide a pivot point for the arms, the sharpening element having: a coil spring portion, arranged at the pivot point, and the pair of arms being integrally formed with the coil spring portion, each arm comprising first and second elongated sharpening portions, respectively, extending from respective ends of the coil spring portion, the coil spring portion and the first and second elongated sharpening portions being spring biased in relation to one another to maintain a crossed relation within housing, each elongated sharpening portion being swingable downwardly in crossed relation about the pivot point in a plane adjacent and parallel the plane of the housing, such that a crossing point of the first and second elongated sharpening portions remains within the slot of the housing wherein: each of the first and second elongated sharpening portions has an upper and lower part and a curved intermediate part extending downwardly from its upper part and relative to the pivot point, and the spring biasing of the sharpening element applies a force sufficient to urge each of the sharpening portions to, as the elongated cutting tool is drawn downwardly through and outwardly away from the slot, maintain its crossed relationship with the other by pivoting toward the other to thereby provide contact sharpening surfaces of each sharpening portion to respective sides of the cutting edge of the elongated cutting tool.

2. The sharpener of claim 1, wherein the sharpening elements are curved sufficiently so as to provide a substantially uniform angle of contact between cutting edge surfaces of the cutting tool and sharpening contacts of the sharpening elements as the cutting tool is moved downwardly and outwardly through the slot of the housing.

3. The sharpener of claim 2, further comprising a mounting base affixed to a bottom of the housing.

4. The sharpener of claim 2, wherein the mounting base is affixed to the housing using a press fit connection.

5. The sharpener of claim 4, wherein the housing has one or more ports, and wherein the mounting base has one or more spring arms each having a tab at an end portion thereof, the press fit connection being provided by engagement of respective ones of the one or more tabs with a respective ones of the ports of the housing.

6. The sharpener of claim 2, wherein each of the first and second elongated sharpening portions are made of metal and have an abrasive surface formed thereon.

7. The sharpener of claim 6, wherein the abrasive surface comprises a diamond electroplating.

8. The sharpener of claim 2, wherein each of the first and second elongated sharpening portions are made of steel and configured as a blade honing surface.

9. The sharpener of claim 2, wherein the sharpening portions terminate, at a top of the sharpener, in respective arcuate vertical end portions.

10. The sharpener of claim 2, further comprising first and second spring pivots configured to engage with one another and with the coil spring portion.

11. The sharpener of claim 10, further comprising a spring pivot bolt and spring pivot nut configured to be threadingly engagable with one another to securely mount the engaged combination of the coil spring portion and the first and second spring pivots to the housing at the anchor region.

12. The sharpener of claim 10, the housing further comprising a pivot hole located at the pivot point, the spring pivot bolt passing through the pivot hole when threadingly engaging the spring pivot nut.

13. The sharpener of claim 10, further comprising a keying engagement between the housing and the first and second spring pivots.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0023] FIGS. 1, 2, 3, 4 and 5 are perspective, front elevation, side, top and bottom views, respectively, of a knife sharpener in an assembled state, including a sharpener base;

[0024] FIG. 6 is a sectional view taken along direction X in FIG. 2;

[0025] FIG. 7 is a sectional view taken along direction Y in FIG. 3;

[0026] FIG. 8 is a partially exploded view of the sharpener with the mounting base in a detached state;

[0027] FIG. 9 is an exploded view showing the components of the sharpener in a disassembled state;

[0028] FIG. 10 is an underside view of the sharpener without the base and with a spring-biased sharpening element in a partially inserted position into a slot of the housing;

[0029] FIG. 11 is a partially exploded view showing the sharpener without the mounting base;

[0030] FIGS. 12 and 13 are sectional views that show the movement of the components of the spring-biased sharpening element during a sharpening operation of a knife blade having an edge;

[0031] FIG. 14 is a detailed view of the spring biased sharpening element and the spring pivots engaged with the coil spring portion; and

[0032] FIG. 15 is a perspective view of the housing of the sharpener showing a keying portion of the sharpener.

DETAILED DESCRIPTION OF THE PRESENTLY PREFERRED EMBODIMENTS

[0033] FIGS. 1-5 show various views of a knife sharpener 1 in an assembled state in accordance with an embodiment of the present invention. The sharpener 1 includes a housing (or base) 2, that in normal usage, is positioned on a counter top and extends in an upright plane. The housing 2 is structured to define an elongated vertically extending slot 4 therein. The slot 4 is preferably lined with a slot liner 6. As will be discussed in greater detail below, during use the user would draw a knife blade downward and through the slot 4.

[0034] As best seen in the sectional views of FIGS. 6 and 7, the sharpener 1 has arranged within the housing 2 a spring biased sharpening element 8 secured to the housing 2 at an anchor region formed in the housing to define a pivot point 14 located below the vertically extending slot 4. This sharpening element 8 has a coil spring portion 10 arranged within, and affixed to, the housing 2 at the pivot point 14 and integrally formed with the coil spring portion 10, first and second elongated sharpening portions 12a and 12b, respectively, each extending from respective ends of the coil spring portion 10. Each of the first and second elongated sharpening portions 12a, 12b has an upper and lower part and a curved intermediate part extending downwardly from its upper part and relative to the pivot point 14.

[0035] Preferably, at least at the elongated sharpening portions 12a and 12b, the spring biased sharpening element 8 comprises an abrasive surface, such as a surface having diamond electroplating, using, for example, 5-10 micron particles. Such a surface would be able to shape the cutting edge, performing true sharpening by removal of metal from the cutting edge until it is sharp. The use of alternative materials will be readily apparent to those of ordinary skill.

[0036] The spring can also be made of a steel surface that is relatively smooth, like that of a chef's honing steel. If the first and second elongated sharpening portions 12a and 12b are provided in this manner, then using the sharpener 1 would reshape, i.e., hone, the edge without removing material from the edge.

[0037] As will be discussed below, the sharpener 1 may include more than one slot, one having first and second elongated sharpening portions 12a and 12b with an abrasive surface for true sharpening, and another having first and second elongated sharpening portions 12a and 12b with a surface similar to that of a chef's steel, for honing the cutting edge. As is known to those of skill in the art, both sharpening and honing results in a blade with an improved cutting ability. Hereinafter, reference to the word sharpen or sharpening will be used mean either true sharpening or honing of the cutting edge.

[0038] Alternatively, the sharpener may provide the ability to readily replace a spring biased sharpening element 8 with the above-described abrasive surface, for a spring biased sharpening element 8 with the above-described honing surface.

[0039] The coil spring portion 10 and the first and second elongated sharpening portions 12a, 12b, are spring biased in relation to one another to maintain the first and second elongated sharpening portions 12a, 12b in a crossed configuration, with each elongated sharpening portion being swingable downwardly in crossed relation about the pivot point 14 in a plane adjacent and parallel to the plane of the housing 2.

[0040] The spring biasing of the sharpening element 8 applies a force sufficient to urge each of the sharpening portions 12a, 12b, as the elongated cutting tool is drawn downwardly through and outwardly away from the slot 4, to maintain its crossed relationship with the other by pivoting toward the other to thereby provide contact sharpening surfaces of each sharpening portion to respective sides of the cutting edge of the elongated cutting tool.

[0041] As can be seen, for example, in FIGS. 1-8, the sharpener 1 includes a detachable mounting base 18. With particular reference to FIG. 8, a partially exploded view with the mounting base 18 in a detached state shows that it can be press-fit into the bottom of the housing 2 to provide a sturdy rest surface for the sharpener 1, for example on a counter top or table top. As will be discussed further below, the mounting base 18, once installed, can also be removed from the housing 2.

[0042] This press-fit feature is facilitated by the provision in the mounting base 18 of plastic leaf spring arms 19 extending upwardly at two outer edges. The tab 20 extends outwardly at the top end of each leaf spring arm 19. During insertion of the mounting base 18 into the opening at the bottom of the housing, the arms 19 will be inwardly compressed by the housing walls, but, due to their resilient spring force characteristics, the arms 19 will maintain an outward biasing force. Upon reaching the height at which the tab 20 is level with the port 22 of the housing, the outward biasing force of the arms 19 causes the snapping in of the tab 20 into the port 22.

[0043] To remove the mounting base 18, for example for cleaning the sharpener 1 or replacing the spring biased sharpening element 8 due to wear, the tabs 20 may be pressed inwardly by the user while the user pulls down on the bottom of the mounting base, allowing the arms 19 to slide easily downwardly along the inner surface of the housing 2 until the arms 19 are free from the housing 2.

[0044] FIG. 9 is an exploded view showing the components of the sharpener 1 in a disassembled state. FIG. 10 is an underside view of the sharpener without the base 18 and with the spring biased sharpening element 8 only partially inserted into the slot 4 of the housing 2. FIG. 11 is a partially exploded view showing the sharpener without the mounting base 18. As can be seen in FIGS. 9, 10 and 11, the coil spring portion 10, prior to insertion into the housing 2, is engaged with a pair of spring pivots 24a and 24b, which engage each other when both are inserted into a respective side of the coil spring portion 10.

[0045] FIG. 10 shows the spring biased sharpening element 8 partially inserted into the housing 2, with the spring pivots 24a, 24b engaged with each other and with the coil spring portion 10. The spring pivots 24a, 24b allow the coil spring portion 10 to be maintained at the pivot point 14 and assist in supplying the biasing of the sharpening portions 12a, 12b during the sharpening of, e.g., a knife, in the sharpener.

[0046] Spring pivot bolt 25 and spring pivot nut 26 are configured to be threadingly engagable with one another to securely mount the coil spring portion 10 and the spring pivots 24a, 24b to the housing. At least one of the spring pivots includes a female keying 116 that engages, upon assembly of the sharpener, with a male keying 115 of the housing. As can be seen from the partial exploded view of FIG. 11, the pivot bolt 25 passes through a pivot hole 29 located at the pivot point 14. Once the bolt 25 has been screwed into the nut 26, the spring biased sharpening element 8 is securely fastened within the housing 2.

[0047] Returning to FIG. 9, the mounting base 18 is attached to a wood or metal counter or table top, or any suitable flat surface, with screws 190.

[0048] FIGS. 12 and 13 are sectional views that show the movement of the components of the spring biased sharpening element 8 within the sharpener 1 during a sharpening operation of a knife blade 30 having an edge 32. In FIG. 12, the edge 32 of the knife blade 30 is resting at the crossing point of the sharpening portions 12a, 12b. While FIG. 12 will be described in regard to a case in which this position is just before the knife will be drawn down and through the sharpener to sharpen the blade, one of skill in the art would appreciate that the position illustrated in FIG. 12 could also occur after a sharpening stroke of the knife has been completed.

[0049] A passing through of the knife blade 30 consists of pushing the knife blade 30 down, by grasping a knife handle. The biasing of the spring biased sharpening element 8 will continually provide an urging force to return to the position of FIG. 12 even during the downward stroke of the knife blade.

[0050] FIG. 13 shows the sharpener in the situation in which the blade 30 has been depressed, and is drawn through the sharpener. As can be seen from comparing FIGS. 12 and 13, the operation of the sharpener involves the user maintaining contact of the knife blade edge 32 with the crossing point of the sharpening portions 12a, 12b. While the edge 32 maintains contact with the point at which the sharpening portions 12a, 12b, the actual vertical height of this crossing point in the groove changes as the blade is moved up and down during the sharpening process.

[0051] Thus, as shown in FIG. 13, upon a pushing down of the knife blade's edge 32, the sharpening portions 12a, 12b, which may, for example, have an abrasive surface, such as a surface having diamond electroplating, guided against the edge 32, apply, e.g., the abrasive surface to the knife edge at an angle appropriate for the type of beveling of the knife.

[0052] The biasing of the sharpening portions 12a, 12b and the coil spring portion 10 provides a force continually urging the sharpening portions 12a, 12b back towards the position of FIG. 12. This causes the edges of each sharpening portion to maintain their contact with the respective knife edge sides regardless of the vertical position of the knife in the slot. This force also provides the user with tactile pressure to the hand of a continuous guiding force to maintain the knife blade in a central vertical direction, which keeps each respective knife edge at an equal angle of incidence with the respective sharpening edge of the respective sharpening portion.

[0053] An upwardly directed spring force is also provided to the bottom of the knife to urge it upwardly, preventing too rapid a downward motion, and making it less likely for the knife to bottom out in the sharpener.

[0054] FIG. 14 is a detailed view of a sharpening element assembly formed by the spring biased sharpening element 8 and the spring pivots 24a and 24b engaged with the coil spring portion 10. As can be seen in FIG. 14, the sharpening portions 12a, 12b of the spring biased sharpening element 8 preferably each have a shape complementary to the other to allow each to, in a rest position, form their crisscrossed relationship. This shape preferably includes bending portions 15a and 15b, proximate the coil spring portion 10. The bending portions deflect each sharpening portion of the sharpening element 8 so that sharpening portion 12a crosses in front of sharpening portion 12b.

[0055] Also, the sharpening portions 12a, 12b terminate, at the top of the sharpener 1, in respective arcuate vertical end portions 13a and 13b, respectively. The arcuate shape of these vertical end portions allow the top part of the spring biased sharpening element 8 to contact the inner side walls of the housing 2 at the lowermost point of the sharpening process, for example, as illustrated in FIG. 13. The arcuate portions 13a and 13b also provide a guide within the housing so that the tops portions smoothly interact with the inside of the housing. Also, the top arcuate portions 13a and 13b are limited in their travel by the internal walls of the housing. This limits their travel such that a knife passing between the arms would never contact the bottom of the sharpener's V-shaped groove.

[0056] As should be understood, the provision of the spring biased sharpening element 8 within the housing 2, allows for symmetrical use of the sharpener 1. That is, during sharpening the blade of the knife can be drawn toward, or pushed away from, the user, without the need to orient the sharpener front-to-back, or back-to-front with respect to the user. Further, this arrangement prevents impact-related misalignment of the sharpening portions of the spring biased sharpening element 8 because the crossed sharpening portions are protected via positioning within the housing.

[0057] FIG. 15 is a perspective view of the housing of the sharpener showing the male keying portion 116 of the sharpener. As can be seen in FIGS. 12-15, this male keying 116 is shaped so as to be able to engage the female keying 115 of the sharpening element assembly. This keying orients the sharpener, keeps the sharpening element assembly centered, and prevents rotation between the keyed elements.

[0058] Thus, while there have been shown and described and pointed out fundamental novel features of the invention as applied to a preferred embodiment thereof, it will be understood that various omissions and substitutions and changes in the form and details of the devices illustrated, and in their operation, may be made by those skilled in the art without departing from the spirit of the invention. For example, it is expressly intended that all combinations of those elements and/or method steps which perform substantially the same function in substantially the same way to achieve the same results are within the scope of the invention. Moreover, it should be recognized that structures and/or elements and/or method steps shown and/or described in connection with any disclosed form or embodiment of the invention may be incorporated in any other disclosed or described or suggested form or embodiment as a general matter of design choice. It is the intention, therefore, to be limited only as indicated by the scope of the claims appended hereto.