Cutting tool with supporting portion for a pre-set grinding angle

Abstract

The present invention relates to a cutting tool (1), in particular a knife, comprising: at least one blade (2) with a blade body (2a) and a cutting edge (2b). In order for it to be possible for someone to grind or polish the cutting tool (1) with precision, even if he has no grinding skill, provision is made according to the invention for the cutting tool (1) to have at least one supporting portion (4), which defines a supporting plane (AE) by means of which, for the purpose of grinding and / or polishing the cutting edge (2b), the cutting tool (1) can be stably placed on a planar underlying surface (U), the blade body (2a) therefore being oriented at a working angle (α) ranging from 65 to 80° in relation to the underlying surface (U). A set for grinding and / or polishing a cutting tool (1) and also a corresponding method are likewise disclosed.

Description

[0001] Cutting tool with support section for preset grinding angle

[0002] The present invention relates to a cutting tool, in particular a knife such as a kitchen knife, comprising: at least one blade with a blade edge and a cutting edge.

[0003] Grinding or polishing tools with rotating grinding or polishing surfaces can be used to grind or polish the cutting edge. Such grinding or polishing tools, also known as "roller grinders," are known, for example, from DE 20 2020 001 180 U1 or EP 3 278 928 A.

[0004] A grinding gauge can be used to position the blade relative to the grinding or polishing tool. This gauge positions the blade at a specified grinding angle to the grinding surface in order to grind the cutting edge at the grinding angle specified by the gauge.

[0005] For a satisfactory machining result, three components must be present and work together: the cutting tool, the grinding gauge, and the grinding / polishing tool. This increases the logistical and coordination effort for the user when grinding or polishing the cutting tool.

[0006] To remedy this problem, the present invention provides the cutting tool according to claim 1, the set according to claim 8 and the method according to claim 10.

[0007] The cutting tool according to the invention is in particular a knife or kitchen knife which comprises at least one blade with a blade edge and a cutting edge, wherein the cutting tool has at least one support section which defines a support plane with which the cutting tool can be stably placed on a flat base for grinding and / or polishing the cutting edge, such that the blade edge (or its extension plane) is aligned at a working angle in the range of 65 to 80° to the base. The working angle refers to the angle between the blade edge (or its extension plane) and the support plane. When the support plane rests on the base, the working angle refers to the angle between the blade edge (or its extension plane) and the base. The grinding angle refers to the angle between the extension plane of the blade edge and the grinding surface.In the aforementioned roller grinder, the grinding surface rotates in a plane perpendicular to the base. The grinding angle ß is therefore calculated from the working angle α using the formula I:

[0008] Formula I: ß = 90° - a. “Stable” in the context of the present invention means that the cutting tool rests on the base with its support plane even during grinding or polishing, whilst maintaining the working angle. The cutting tool is preferably held by the handle by a user and pressed onto the base with its support plane. It is desirable, although not necessary, that the cutting tool can rest stably on the base with its support section automatically, i.e. without the application of external force. The centre of gravity of the cutting tool, when projected onto the base, is preferably in the area (between the support points) of the support section when the cutting tool rests on the base with its support section. In order to ensure that the cutting tool rests on the base with its support section during grinding or polishing, the cutting tool is stable.In order to apply a counterforce to the force exerted on the blade by the grinding / polishing tool during polishing, it is advantageous if the cutting tool is held firmly by the user during grinding or polishing and the support section is pressed against the base. During grinding or polishing, the cutting edge of the blade is preferably facing away from the base and the back of the blade is facing the base (see Fig. 4). However, it is generally also possible to arrange the support section on the cutting tool in such a way that the cutting edge of the blade points towards the base during grinding or polishing and the back of the blade points away from the base. The working angle can be set in the range of 65 to 80 ° during manufacture of the cutting tool or, if necessary, by adjusting the support section before grinding or polishing begins.When polishing, the working angle is preferably constant so that the cutting edge is ground evenly and sharply.

[0009] Advantageous developments of the invention are the subject matter of the dependent claims.

[0010] It can be advantageous if the working angle is in the range of 70 to 75°. Grinding angles of 15° or 20° have proven particularly advantageous in practice. A grinding angle of 15° is used for sharpening a very sharp blade, such as a filleting knife used for cutting meat. At a grinding angle of 20°, the cutting edge is less sharp but subject to less wear. The sharpness and wear characteristics of the cutting edge can be adjusted by selecting a grinding angle in the range of 15 to 20°, which corresponds to a working angle of 70 to 75°.

[0011] It may prove useful if the cutting tool has a handle body, wherein the handle body preferably has at least one of the support sections, wherein the support section is preferably arranged on a side of the handle facing away from the cutting edge (e.g., on the back of the handle). A contact force can be exerted on the handle body, particularly during grinding or polishing, in order to press the cutting tool, which rests in the machining position with its support plane on the base, onto the base. This can improve the static friction between the cutting tool and the base.

[0012] It can be useful if the support section has at least three support points lying in the support plane which are not on the same line, wherein preferably at least 25%, 30% or 40% of the total length of the cutting tool, which is preferably measured between a blade tip and an end of a handle body facing away from it, lies between two of these support points, wherein preferably at least one of these support points has a distance from a plane of extension of the blade that is greater than 1%, 2% or 3% of the total length of the cutting tool. The stability of the arrangement is not dependent on the size of the support section, but rather on the distances between the support points in the support plane, in particular perpendicular to the plane of extension of the blade. Even if the relative movement between the cutting edge and the grinding / polishing tool is generally in orparallel to the plane of extension of the blade, there are usually force components during grinding or polishing that act transversely to the plane of extension of the blade and displace the blade and the cutting tool from their intended machining position. A large contact area between the cutting tool and the base increases the static friction of the cutting tool to the base and stabilizes the cutting tool in the machining position. It can be advantageous if the support section is designed to be elastic, particularly as a silicone coating. This can further improve the static friction between the cutting tool and the base.

[0013] It may prove useful if the cutting tool has two such support sections, arranged on different sides (of a plane of extension) of the blade, each defining a support plane with which the cutting tool can be securely placed on the flat surface for grinding the cutting edge, so that the blade (or its plane of extension) is aligned at the same working angle to the surface. This allows the cutting edge to be ground or polished particularly evenly on both sides.

[0014] It can be practical if the support section is adjustable on the cutting tool. This allows the cutting edge to be ground or polished at a specific grinding angle depending on the application. It can prove helpful if the support section can be adjusted between at least two different positions to change the working angle. Preferably, the working angle is 70° in a first position of the support section and 75° in a second position of the support section. This results in the grinding angle being 20° in the first position and 15° in the second position.

[0015] A further aspect of the present invention relates to a set comprising a cutting tool according to one of the preceding embodiments and a grinding and / or polishing tool with at least one grinding and / or polishing surface which rotates in a plane oriented perpendicular to the base when the grinding and / or polishing tool rolls.

[0016] It may be advantageous if the grinding and / or polishing tool has a cylindrical handle body, with such a grinding and / or polishing surface arranged at each axial end of the handle body. These designs of a grinding / polishing tool have proven to be versatile and have proven particularly effective in practice.

[0017] A further aspect of the present invention relates to a method for grinding and / or polishing a cutting tool according to one of the preceding embodiments, the method comprising the following steps:

[0018] Step A: Position the cutting tool with the support surface on the flat surface so that the blade is positioned at a working angle in the range of 65 to 80 degrees to the surface. Preferably, the cutting tool is pressed onto the surface by a user, exerting force, with the support section so that the cutting edge deflects away from the surface.

[0019] Step B: Applying the cutting edge to a grinding and / or polishing surface of a grinding and / or polishing tool, oriented perpendicular to the base. A roller grinder, as known, for example, from EP 3 278 928 A, has grinding or polishing surfaces (a cylindrical body with two end faces) that rotate in a plane oriented perpendicular to the base as the roller grinder rolls along the flat base.

[0020] Step C: Grinding and / or polishing the cutting edge by exerting a relative movement between the grinding and / or polishing surface and the cutting edge. The cutting tool preferably remains stationary relative to the support, while the grinding / polishing tool rolls along the cutting edge in the longitudinal direction of the cutting edge. Due to slight contact pressure between the cutting tool and the grinding / polishing tool, the grinding or polishing surface removes material from the blade during the relative movement, thus grinding or polishing the cutting edge.

[0021] Further advantageous developments of the invention result from combinations of the features disclosed in the description, the claims and the figures.

[0022] Short description of the characters:

[0023] They show:

[0024] Fig. 1 is a schematic side view of a cutting tool according to the invention in the form of a kitchen knife with a blade, a handle body and support sections arranged on the handle body, which define a support plane for supporting the cutting tool on a flat base.

[0025] Fig. 2 is a schematic side view of the cutting tool from Fig. 1 from the other side.

[0026] Fig. 3 is a sectional view in the section plane AA from Fig. 1 .

[0027] Fig. 4 is a schematic front view of the cutting tool according to the invention, looking towards the blade tip, wherein the cutting tool rests as intended with one of the support surfaces on a flat base, so that the blade is aligned at a predetermined working angle to the base, and wherein the cutting edge of the blade is machined with a grinding and / or polishing tool.

[0028] Detailed description of the preferred embodiments:

[0029] A preferred embodiment of the invention will be described in detail below with reference to the accompanying figures.

[0030] Figure 1 shows a side view of a cutting tool 1 according to the invention, which is designed as a kitchen knife. This kitchen knife 1 comprises a flat, elongated blade 2 with a blade face 2a, a convexly curved cutting edge 2b on the underside, a straight blade spine 2c on the top, and a front tip 2d. The blade 2 extends in a plane (extension plane E) and is connected to a handle 3, for example approximately cuboid-shaped or optionally cylindrical, which extends as an extension of the blade 2. This handle 3 has a concave receptacle for the user's fingers on the underside, as shown in Figs. 1 and 2. The handle 3 can be designed as a one-piece handle body. Alternatively, it is also possible for two handle half-shells to be arranged on different sides of the blade 2 instead of a continuous handle body 3, or for the blade 2 to be arranged like a sandwich between the two handle half-shells.

[0031] On the top side or on the back of the handle 3, on each side of the blade 2, there is a support section 4 which is aligned at an angle α to the extension plane E of the blade 2 and defines a support plane AE in order to be able to place the cutting tool 1 stably on a flat surface U (e.g. kitchen worktop) for grinding or polishing the cutting edge 2b. These support sections 4 are arranged symmetrically to the extension plane E of the blade 2a on both sides of the cutting tool 1, so that the cutting edge 2b can be ground symmetrically to the extension plane E of the blade 2a with an identical grinding angle β.

[0032] In the present embodiment, each support section 4 is formed as a continuous surface on the back of the handle 3. The two support sections 4 meet at the spine of the handle 3 in the extension plane E of the blade 2a and form a superposed angle of 360° - 2 * a. It is not necessary for each support section 4 to form a continuous, flat surface on its own. It is also possible for several discrete and spaced-apart support sections 4 or support points 4a, 4b, 4c to jointly define the support plane AE. For example, at the front end (facing the tip 2d) and the rear end (facing away from the tip 2d) of the handle 3, two spaced-apart projections can be formed as support sections 4 or support points 4a, 4b, 4c to define the support plane AE.This variant would have the advantage that the handle 3 can be anatomically shaped for intended use by the user, particularly on the back of the handle, without the support sections 4 being haptically perceptible to the user when holding the handle 3. For the stability of the cutting tool 1 in the intended processing position, it is helpful if at least three different support points 4a, 4b, 4c of each support section 4 are spaced as far apart as possible, particularly in the longitudinal direction L of the cutting tool 1 and perpendicular to the extension plane E of the blade 2a, so that the blade 2a can be held in engagement with the grinding / polishing surface 5a at a constant working angle a during the intended grinding / polishing process. In the present example, the kitchen knife 1 has a total length L of approximately 30 cm.The two support points 4a, 4b of the support section 4 at the front and rear ends of the handle 3 are ideally spaced from each other by a distance X corresponding to at least 30% of the length L. The distance X between the support points 4a and 4b, which is preferably measured along the entire length of the cutting tool 1, is shown in Figure 2 and is therefore at least 9 cm. This can, for example, prevent the blade spine 2d from coming into contact with the base U during the intended grinding / polishing of the cutting edge 2b. Ideally, the center of gravity of the cutting tool 1, when projected perpendicularly onto the support plane AE defined by the support section 4, is located exactly in the area of ​​the support section 4 or within the area defined by the support points 4a, 4b, 4c.

[0033] Furthermore, as shown in Figure 3, the support point 4b has a distance Y from the extension plane E of the blade 2a, which is at least 1%, i.e. 3 mm, of the total length (here 30 cm or 300 mm) of the cutting tool 1. The greater the distance Y of the outermost support point 4b in the support plane AE from the extension plane E of the blade 2a, the lower the tendency of the cutting tool 1 to tilt in the machining position. This can prevent the working angle α from changing unintentionally during the intended grinding / polishing process. In principle, a larger distance Y is desirable to increase the stability of the cutting tool 1 in the intended machining position, as shown in Figure 4, but the distance A should not be so large that the handling of the cutting tool 1 during cutting is adversely affected.

[0034] In the illustration according to Figure 3, the cutting tool 1 according to the invention has a symmetrical cross-sectional profile.

[0035] In the present exemplary embodiment, the angle α between the support plane AE and the extension plane E of the blade 2a is 70°. When the cutting tool 1 rests with the support plane AE on the flat base U, this angle α corresponds to the so-called working angle α between the extension plane E of the blade 2a and the flat base U. As a result, the blade 2a is automatically positioned at an ideal grinding angle β of 20° relative to the grinding surface 5a of a grinding / polishing tool 5 mentioned above. The grinding / polishing surface 5a of such a grinding / polishing tool 5 is known to rotate in a plane oriented perpendicular to the base U when the tool 5 rolls on the base U as intended.

[0036] For intended use, the cutting tool 1 is first placed or pressed onto the flat base U with the support plane AE so that the blade 2a is arranged at the predetermined working angle a of 20°, which corresponds to the angle between the support section 4 and the extension plane E of the blade 2a, to the base U (step A). ​​The user preferably exerts the pressure force on the handle 3 so that the force introduced into the handle 3 acts directly on the base U via the support section 4 arranged on the handle 3 and stabilizes the cutting tool 1 in the processing position.

[0037] Subsequently, the cutting edge 2b is placed on a grinding or polishing surface 5b of a grinding or polishing tool 5 aligned perpendicular to the base U (step B) and then ground or polished by exerting a relative movement between the grinding or polishing surface 5b and the cutting edge 2b in the longitudinal direction of the cutting edge 2b (step C).

[0038] In order to grind the cutting edge 2b on both sides, the cutting tool 1 is placed on the support U with the support plane AE defined by the other support section 4. Then, the above-mentioned steps (A to C) are repeated.

[0039] In an embodiment not shown, which is essentially based on the preceding embodiment and has identical features except for the differences mentioned below, the support section 4 is adjustable to change the working angle α and can, if necessary, be adjusted between a first position in which the working angle is, for example, 70°, and a second position in which the working angle is, for example, 75°. Ideally, the support section 4 can be locked in both the first and second positions, thus preventing an unintentional change in the working angle α.

[0040] Further advantageous developments of the invention are possible within the scope of protection of the patent claims.

[0041] The advantage of the present invention essentially lies in the fact that the cutting tool 1 according to the invention can be positioned at a corresponding grinding angle β to the grinding surface 5 without any additional aids. In particular, a knife 1, whose handle 3 has the support section 4 according to the invention, can be tilted to the left and / or right and held very easily and securely at the corresponding grinding angle β without any additional aids. The entire handle 3 could be ground flat. However, the handle 3 could also be ground hollow lengthwise, so as to have a support or support points only on two edges. Rounded protruding rivets, which represent a four-point support, would even be conceivable. List of reference symbols

[0042] 1 cutting tool (knife)

[0043] 2 blades

[0044] 2a blade

[0045] 2b Cutting edge

[0046] 2c blade back

[0047] 2d blade tip

[0048] 3 handle

[0049] 4 support section

[0050] 5 Grinding and / or polishing tools

[0051] 5a Grinding and / or polishing surface

[0052] 5b Grinding and / or polishing disc

[0053] 5c Handle body

[0054] AE support level

[0055] E Level (of the blade)

[0056] S grinding plane

[0057] U pad

Claims

Claims: Cutting tool (1), in particular a knife, comprising: at least one blade (2) with a blade face (2a) and an edge (2b), wherein the cutting tool (1) has at least one support section (4) that defines a support plane (AE) with which the cutting tool (1) can be stably placed on a flat surface (U) for grinding and / or polishing the edge (2b), such that the blade face (2a) is oriented at a working angle (a) in the range of 65 to 80° to the surface (U). Cutting tool (1) according to the preceding claim, characterized in that the working angle (a) is in the range of 70 to 75°.Cutting tool (1 ) according to one of the preceding claims, characterized in that the cutting tool (1) has a handle (3), wherein the handle (3) preferably has at least one of the support sections (4), wherein the support section (4) is preferably arranged on a side of the handle (3) that deflects away from the cutting edge (2b).Cutting tool (1) according to one of the preceding claims, characterized in that the support section (4) has at least three support points (4a, 4b, 4c) lying in the support plane (AE) which are not on a line, wherein preferably at least 25%, 30% or 40% of the total length (L) of the cutting tool (1), which is preferably measured between a blade tip (2d) and an end of a handle (3) facing away from it, lies between two of these support points (4a, 4b), wherein preferably at least one of these support points (4b) has a distance (Y) from a plane of extension (E) of the blade (2a) which is greater than 1%, 2% or 3% of the total length (L) of the cutting tool (1).Cutting tool (1) according to one of the preceding claims, characterized in that the cutting tool (1) has two support sections (4) arranged on different sides of the blade (2a), each defining a support plane (AE) with which the cutting tool (1) can be stably placed on the flat surface (U) for grinding the cutting edge (2b), such that the blade (2a) is always aligned at the same working angle (a) to the surface (U). Cutting tool (1) according to one of the preceding claims, characterized in that the support section (4) is adjustably arranged on the cutting tool (1). Cutting tool (1) according to the preceding claim, characterized in that the support section (4) is adjustable between at least two different positions for changing the working angle (a), wherein preferably the working angle (a) is 70° in a first position of the support section (4) and is 75° in a second position of the support section (4). Set comprising a cutting tool (1) according to one of the preceding claims and a grinding and / or polishing tool (5) with at least one grinding and / or polishing surface (5b) which rotates in a plane (S) perpendicular to the surface (U) when the grinding and / or polishing tool (5) rolls on the flat surface (U). Set according to the preceding claim, characterized in that the grinding and / or polishing tool (5) has a cylindrical handle body (5c) wherein such a grinding and / or polishing surface (5b) is arranged at each axial end of the handle body (5c).A method for grinding and / or polishing a cutting tool (1) according to one of the preceding claims, characterized in that the method comprises the following steps: a. Arranging the cutting tool (1) with its support plane (AE) on the flat base (U) such that the blade (2a) is arranged at a working angle (a) in the range of 65 to 80 degrees to the base (U). b. Applying the cutting edge (2b) to a grinding and / or polishing surface (5b) of a grinding and / or polishing tool (5) oriented perpendicular to the base (U). c. Grinding and / or polishing the cutting edge (2b) by exerting a relative movement between the grinding and / or polishing surface (5b) and the cutting edge (2b) (in the longitudinal direction of the cutting edge (2b)).

Images