WO2023169834A1

WO2023169834A1 - A grinding angle setting device, a grinding system and a method of setting a grinding angle

Info

Publication number: WO2023169834A1
Application number: PCT/EP2023/054593
Authority: WO
Inventors: Håkan Persson
Original assignee: Tormek Ab
Priority date: 2022-03-07
Filing date: 2023-02-23
Publication date: 2023-09-14
Also published as: SE2250303A1; SE545039C2

Abstract

This disclosure presents a grinding angle setting device (100) for cooperative use with a grinding machine (200). The grinding machine (200) comprises a grinding means (210) and a support means (220) for supporting a grinding jig (1) holding a blade (300) to be grinded. The grinding angle setting device (100) comprises a first surface (111) that is configured to be brought in contact with the support means (220), a second surface (121) that is configured to be brought in contact with the grinding means (210), and an indicating means (130) for indicating the grinding angle (a) that corresponds to the current position of the adjustable support means (220) in relation to the grinding means (210). There is further presented a grinding system and a method (400) of setting a grinding angle.

Description

A GRINDING ANGLE SETTING DEVICE, A GRINDING SYSTEM AND A METHOD OF SETTING A GRINDING ANGLE

Technical field

The present disclosure generally pertains to grinding of blade tools. More precisely, the present disclosure relates to the setting of a grinding angle, a grinding angle setting device, and a grinding system comprising such device.

Background art

Grinding of blade tools, such as knives, which have edges with opposite edge bevels is typically made by clamping the blade tool in a grinding jig and moving the blade across a revolving grinding wheel or grindstone of a grinding machine. For accurate grinding, the grinding jig is preferably supported by a support of the grinding machine. When the edge bevel on the first side of the tool has been sharpened, the grinding jig is turned over and moved in opposite direction across the grinding wheel so that edge bevel on the second side of the blade is sharpened. The position of the support in relation to the grinding wheel, the design of the grinding jig and how the latter clamps the tool are examples of factors that affect the grinding angle.

Various tools and instruments have been proposed to obtain a desired grinding angle.

The prior art document EP 1818138B1 describes sharpening of a tool edge by means of a grinding machine using a jig to hold the tool, and discloses a tool setter for adjusting the position of a support bar of the grinding machine. The tool setter comprises a plurality of holes enabling sharpening with different parameters, and a plurality of shoulders for setting how far the tool protrudes from the jig.

EP0957331B1 discloses an angle gauge with a cam plate for abutting a grinding wheel and an elongated body for abutting a tool to be grinded. The cam plate and the elongated body are individually rotatable to set the diameter of the grinding wheel and the desired cutting angle, respectively.

US5172484A discloses a grinding machine having a grinding wheel and a tool rest, an angle measuring device being used to set the tool rest angle.

There are also tables, mobile phone apps and formulas proposed for obtaining a desired grinding angle (see www.sharpeninghandbook.info/GT -Knives-DutchmanGuide.html and references therein). In these cases, however, relatively exact measurements are to be performed and a certain level of skill and experience is required.

An object of the present disclosure is to provide for high precision grinding of a blade tool in a non-complex manner.

Summary of the invention

It is in view of the above considerations and others that the embodiments of the present invention have been made. According to a first aspect of the present disclosure, there is provided a grinding angle setting device for cooperative use with a grinding machine. In other words, the grinding angle setting device is configured for use with the grinding machine. The grinding machine comprises a grinding means and a support means for supporting a grinding jig holding a blade to be grinded, the support means being adjustable in relation to the grinding means to set a grinding angle. The grinding angle setting device comprises a first surface that is configured to be brought in contact with the support means, a second surface that is configured to be brought in contact with the grinding means, and an indicating means for indicating the grinding angle that corresponds to the current position of the adjustable support means in relation to the grinding means when the first surface is brought in contact with the support means and the second surface is brought in contact with the grinding means.

The grinding angle may thus quickly and accurately be set by a user without any prior expertise or skill. There is no need to perform any measurements. The single item to be set is the adjustable support means. A further advantage is that the grinding angle setting device may be relatively inexpensive to manufacture.

The grinding angle setting device may be designed such that a desired grinding angle may be set when the grinding angle setting device is in contact with the grinding machine, and that desired grinding angle will then apply when the grinding jig and the blade are brought in contact with the grinding machine. The grinding angle setting device may be positioned in contact with the grinding machine and the support means may be continuously adjusted until the desired grinding angle is indicated by the indicating means.

Thus, the present grinding angle setting device brings the advantage that a user may utilise the grinding angle setting device to set the adjustable support means, and subsequently use the grinding jig to grind the blade. In other words, the adjustable support means is set at a desired position that corresponds to a desired grinding angle. The grinding angle setting device is configured to be brought in contact with the grinding machine to set the position of the adjustable support means, and that position subsequently results in the desired grinding angle when the grinding jig, holding the blade, are brought in contact with the grinding machine.

The above procedure is much more straightforward than the previous tables, mobile phone apps or formulas that require several precise measurements, accurate inputs and a certain level of skill and experience. Manual measurements and inputs are always associated with uncertainties and faults. Further, there may exists errors and/or approximations in methods that are based on calculations. Thus, the present grinding angle setting device provides uncomplicated, exact and quick setting of an accurate grinding angle.

The grinding angle setting device may alternatively be referred to as a grinding angle measuring device, as it may be used to measure the grinding angle that corresponds to a current setting of the adjustable support means. The first surface, which is to be brought in contact with the support means, may be of a similar or the same shape as the portion of the grinding jig that is to be brought in contact with the support means during grinding.

The grinding angle setting device may comprise a first part on which the first surface is positioned and a second part on which the second surface is positioned, wherein the first and second parts are pivotally connected to one another around a pivot axis. Such a device may be particularly cost effective and easy to manufacture.

The first and second parts may be pivotally connected to one another by a hinge joint comprising a bearing pin that is rotatably journalled in a bushing. Such a grinding angle setting device may be sturdy and easy to manufacture. The first part may comprise the bushing and the second part may comprise the bearing pin.

The grinding angle setting device may comprise a blade receiving surface that is configured to receive the blade when held by the grinding jig. The blade receiving surface may be designed to securely receive the edge of the blade. For example, the blade receiving surface may comprise an angle. In use, the blade may abut against the angle of the blade receiving surface.

The blade receiving surface may be of a sufficient length to stably support the blade. The length of the blade receiving surface may be at least 25 mm. It is to be understood that the receiving surface may be continuous or may be formed by two or more discrete blade supports. In the latter case, the length of the blade receiving surface is the distance between the discrete blade supports.

The blade receiving surface may coincide with the pivot axis of the first and second parts. Such a grinding angle setting device may be especially accurate, and also be cost effective and easy to manufacture. Advantageously, the bearing pin comprises the blade receiving surface.

The indicating means may comprise an indicator on the first or second part and a scale on the other one of the first and second part. The scale may present various grinding angles and the indicator, typically a sharp pointer, may show the grinding angle that corresponds to the current setting of the support means. As the adjustable support means is adjusted, the indicator may continuously appoint the corresponding grinding angle on the scale.

The indicating means may be located closer to the first surface than to the second surface. Such a grinding angle setting device may be especially accurate. Such a grinding angle setting device may have an accuracy of at least half a degree. The distance between the first and second surface is typically at least 80 mm. The first and second surfaces may be arranged on first and second parts that are pivotally connected to one another in the vicinity of the second surface. Thus, a hinge joint connecting parts on which the first and second surfaces may be located is closer to the second surface than to the first surface.

The distance between the first surface and the second surface may be adjustable. In other words, the grinding angle setting device may be adaptable to the combined length of the jig and the blade held by the jig. More precisely to the combined length of the jig and the portion of the blade width that protrudes out from the jig in the longitudinal direction of the jig. For example, the grinding angle setting device may comprise an extendable arm on which the first surface is positioned.

As mentioned, the grinding angle setting device may comprise a first part on which the first surface is positioned and a second part on which the second surface is positioned. In addition, the length of the first part may be adjustable such that it is adaptable to the combined length of the jig and the blade held by the jig. For example, the first part may comprise an extendable arm on which the first surface is positioned.

The first surface may be shaped to at least partially surround the support means such that the grinding angle setting device may be suspended on the support means. In this may the grinding angle setting device is particularly easy to use, and also very accurate. The first surface may be configured such that it may be suspended on a support means that extends essentially horizontally. The first surface may be U-shaped and thus fit a support means of circular cross-section. The second surface may be configured to be aligned with the grinding means. In other words, by means of the second surface, the second part may be aligned with the grinding means. More precisely, aligned with the grinding means at the contact point where the blade is to be grinded by the grinding means.

The second surface may be attached to the second part in a manner allowing the position of the second surface to be adjusted in relation to the second part, typically linearly adjusted. For example, the second surface may be attached to the second part via an eccentric connection such that the position of the second surface may be adjusted in relation to the second part. This allows for an adjustment of the grinding angle setting device to grinding means of various sizes, such as grinding wheels of different radiuses. The second surface may for example be arranged on a contact bracket.

The second surface may comprise two contact points that are separated as seen along a circumference of the grinding means. The two contact points may be separated such that the second surface may be aligned with the grinding means, e.g. a grinding or honing wheel. Two separated contact points allow a user to visually inspect a correct positioning of the second surface with respect to the grinding means. The two contact points may be formed by two contact bars that protrude from the contact bracket. Advantageously, the blade receiving surface may be located between the two contact points, preferably equidistant between the two contact points.

The grinding angle setting device may comprise a grinding end intended to face the grinding means in use. The grinding angle setting device may comprise a support end intended to face the support means in use. The grinding end and the support end may form opposite ends of the grinding angle setting device.

The grinding end may comprise the first surface and the support end may comprise the second surface. The grinding angle setting device may comprise a first part on which the first surface is positioned and a second part on which the second surface is positioned, the first and second parts may be pivotally connected to one another at the grinding end. The support end may comprise the indicating means. According to a second aspect of the present disclosure, there is provided a grinding system comprising a grinding jig for holding a blade to be grinded, a grinding machine comprising a grinding means and a support means for supporting the grinding jig, the support means being adjustable in relation to the grinding means to set a grinding angle, and a grinding angle setting device as described above.

The grinding machine may comprise linear adjustment means for straight, linear adjustment of the support means in relation to the grinding means.

The grinding jig is typically adapted to hold, e.g. clamp, the blade with the longitudinal direction of the grinding jig being orthogonal to the longitudinal direction of the grinding jig. Thus, the blade is directed transverse the grinding jig.

The grinding jig may for example comprise a first and a second clamp portion that are movable with respect to one another to clamp the blade, and an elongate support portion for supporting the grinding jig onto the support means of the grinding machine. The elongate support portion may comprise a first support leg carrying the first clamp portion and a second support leg carrying the second clamp portion, wherein the elongate support portion extends along a longitudinal center axis Y of the grinding jig and comprises a radial abutment surface for abutment against the support means of the grinding machine. The first and second support legs of the support portion may be fixed to one another at the radial abutment surface.

Such a grinding system may provide very high precision grinding of the blade.

Since the first and second support legs of the grinding jig are fixed to one another at the radial abutment surface, the distance between the first and second support legs is constant where the grinding jig is supported onto the support means of the grinding machine.

In more detail, the radial distance between the first and second support legs is constant where the grinding jig is supported onto the support means of the grinding machine. In other words, the radial thickness of the elongate support portion is constant at its axial position where the elongate support portion is supported onto the support means during normal use. During normal use the radial abutment surface is supported against the support means. At the radial abutment surface, the distance between the first and second support legs is not affected by the clamp portions being moved with respect to one another, i.e. selectively separated or brought together to clamp or release the blade.

Since the first and second support legs of the support portion are fixed to one another at the radial abutment surface, the blade thickness does not affect the grinding angle. In addition, the grinding jig facilitates the grinding angle remaining the same for the grinding of both sides of the blade.

According to a third aspect of the present disclosure, there is provided a method of setting a grinding angle for grinding a blade held by a grinding jig, e.g. as the one described above. The grinding is performed using a grinding machine having a grinding means and a support means for supporting the grinding jig, wherein the support means is adjustable in relation to the grinding means to set the grinding angle. The method comprises using a grinding angle setting device as described above and fastening the blade in the grinding jig, bringing the first surface of the grinding angle setting device in contact with the support means and the second surface thereof in contact with the grinding means, aligning the second surface of the grinding angle setting device with the grinding means, obtaining the current grinding angle from the indicating means of the grinding angle setting device, and adjusting the support means in relation to the grinding means if the current grinding angle deviates from a desired grinding angle.

Bringing the first surface of the grinding angle setting device in contact with the support means may comprise suspending the grinding angle setting device on the support means.

The method may comprise adjusting the distance between the first surface and the second surface of the grinding angle setting device to the grinding jig and the blade held by the grinding jig.

The method may comprise adjusting the position of the second surface in relation to the second part in view of the radius of a grinding means in the form of a grinding wheel. Further features and advantages of such a grinding system and method correspond to the ones mentioned above in relation to the grinding angle setting device.

According to a further aspect of the present disclosure, there is provided a grinding angle setting device as shown in any of figures 1 to 7.

Brief description of the drawings

These and other aspects, features and advantages will be apparent and elucidated from the following description of various embodiments, reference being made to the accompanying drawings, in which: figure 1 is an isometric view of a grinding angle setting device, figure 2 shows a grinding system comprising the grinding angle setting device of figure 1, a grinding jig and a grinding machine with grinding means and support means, a knife with a blade to be grinded is also shown, figure 3 is an exploded view of the grinding angle setting device of figure 1, figure 4 is an isometric view of the rear side of the grinding angle setting device of figure 1, figure 5 is a side view of the grinding angle setting device of figure 1, the grinding jig holding a blade and a grinding means and a support means of the grinding machine, figure 6 is similar to figure 5 but without the grinding jig and the blade, figure 7 shows a grinding system similar to the one of figure 2 but with the support means differently oriented, figure 8 illustrates a method of setting a grinding angle using a grinding angle setting device of figure 1, figure 9 is an isometric view of a grinding jig that may form part of the grinding system of figures 2 or 7, figure 10 is similar to figure 2 but without the grinding angle setting device, figure 11 is an exploded view of the grinding jig of figure 9, figure 12 is a side view of the grinding jig of figure 9, and figure 13 is a side view of a grinding jig according to an alternative embodiment.

Detailed description of embodiments

The grinding angle setting device, the grinding system and the method of setting a grinding angle according to the present disclosure will now be described more fully hereinafter. The device, system and method according to the present disclosure may however be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided by way of example so that this disclosure will be thorough and complete, and will fully convey the scope of the present disclosure to those persons skilled in the art. Same reference numbers refer to like elements throughout the description and drawings.

Figures 1 to 7 show a possible real implementation of the grinding angle setting device 100 according to the present disclosure. The grinding angle setting device 100 is configured for cooperative use with a grinding machine 200, as is illustrated in figures 2, 5, 6 and 7. The grinding angle setting device 100 may be made of plastic material, preferably fiber reinforced plastic material.

Figures 2 and 5 show the grinding angle setting device 100 together with a grinding machine 200 and a grinding jig 1. A blade tool (figures 2 and 10) in the form of a knife with a blade 300 to be ground is clamped in the grinding jig 1. The grinding machine 200 may be of the bench type, i.e. of a design that allows it to be placed on a table in e.g. a workshop or a kitchen and to be operated manually by a user. The grinding machine 200 has a housing and comprises a grinding means 210 in the form of a cylindrical grindstone or a cylindrical grinding wheel having a cylindrical grinding surface. The grinding wheel 210 is rotated in a rotation direction R by a motor (not shown) which may be connected to a grinding shaft 230 running through the center of the grinding wheel 210. The motor may for example be an electrical motor. A trough 240 for grinding liquid, such as water or oil, may be arranged underneath the grinding wheel 210. The grinding machine 200 further comprises a support means 220 in the form of a support bar, for supporting the grinding jig 1. The support bar 220 extends in parallel with the shaft 230 and thus in parallel with the rotation axis of the cylindrical grinding wheel 210, i.e. transverse the rotation direction R of the grinding wheel 210. In figures 2 and 5, the blade 300 clamped by the grinding jig 1 is in a grinding position ready to be grinded by the grinding wheel 210.

The grinding machine may also comprise a second grinding means 210 in the form of a cylindrical honing wheel, illustrated to the left in figures 2, 7 and 10, on the opposite lateral end of the grinding machine 200. As is shown, the grinding wheel and the honing wheels may be mounted to the same grinding shaft 230 at opposite ends thereof. As is clear from a comparison of figure 2 and 7, the support bar 220 may be selectively arranged such that it either extends over the grinding wheel or over the honing wheel. Below, reference will primarily be made to grinding the blade 300 using the grinding wheel 210.

The grinding machine 200 may be any type of conventional grinding machine, provided with a support means 220, for grinding blade tools such as knives. Such a knife may have a handle and a blade 300 with a back and a symmetric edge with two opposing edge bevels. Edge bevels may also be denominated grind bevels. The grinding machine may be a Tormek T-8 which is commercially available from the company Tormek AB.

The support means 220, hereinafter support bar, may be adjustable 460 (see double arrow in figures 2, 5 and 7) such that the grinding angle between the blade 300 and the grinding wheel 210 may be altered. The support bar 220 may for example be adjustable in height (figures 2 and 5) in relation to the grinding wheel or laterally (figure 7) in relation of the grinding (honing) wheel. A grinding machine with such a support bar is disclosed in EP1818138B1.

As is shown in figure 2, the grinding shaft 230 extends out from one lateral side of the grinding machine 200, more precisely from the machine housing. The grinding wheel 210 is carried by the grinding shaft 230 and is located at one side of the grinding machine 200, externally the machine housing. The cylindrical grinding wheel 210 comprises a peripheral grinding surface against which the blade 300 is grinded. The grinding wheel 210 may alternatively be referred to as a peripheral grinding wheel. As discussed, the grinding machine may in addition be provided with a honing wheel. The grinding shaft 230 may extend from the opposite lateral side of the grinding machine housing to carry the honing wheel externally the machine housing, as is illustrated.

In a grinding operation, as indicated in figures 2, 5 and 10, the grinding jig 1 together with the clamped blade 300 are first moved in a first direction (e.g. left) across the grinding wheel 210 to grind a first side edge bevel of the blade 300. Then, the grinding jig 1 together with the blade is turned around where after the blade 300 is moved in a second direction (e.g. right) across the grinding wheel 210. The grinding machine 200 and the grinding jig 1 are configured such that the blade 300 is held transverse the rotation direction R of the grinding wheel 210, such that the blade 300 is grinded transverse its longitudinal direction. A similar operation is described in EP3722047B1.

Advantageously, grinding is performed with the edge of the blade 300 facing opposite the rotational direction R of the grinding wheel, whereas honing is performed with the edge of the blade 300 facing along the rotational direction of the honing wheel.

As is described below, the support bar 220 may be set 460 at a specific distance in relation to the grinding wheel 210 to obtain a desired grinding angle a (denoted in figure 5). In accordance with the present disclosure, the grinding angle setting device 100 is provided to accurately set, or position, the support bar 220.

To set the grinding angle a, the grinding angle setting device 100 is brought in contact with the support bar 220 and with the grinding wheel 210. The support bar 220 may then be adjusted 460 to set the grinding angle a. The grinding angle a is the angle at which the blade 300 is grinded by the grinding wheel 210 when held by the grinding jig 1, when the grinding jig 1 is brought in contact with the support bar 220 and the blade 300 is brought in contact with the grinding wheel 210. More precisely, the grinding angle a is the angle between the longitudinal axis Y of the grinding jig 1 and the tangent line to the periphery of the grinding wheel 210 at the contact point, see figure 5. As is clear from figure 7, the grinding angle setting device 100 may in a similar manner also be used together with the honing wheel. The support bar 220 may for example be adjustable in height (figure 2) in relation to the grinding wheel or laterally (figure 7) in relation of the grinding (honing) wheel.

Referring to figures 1 to 7, the grinding angle setting device 100 comprises a first surface 111 that is configured to be brought in contact with the support bar 220 and a second surface 121 that is configured to be brought in contact with the grinding wheel 210. The grinding angle setting device 100 further comprises an indicating means 130 for indicating the grinding angle a that corresponds to the current position of the adjustable support bar 220 in relation to the grinding wheel 210 when the first surface I l l is brought in contact with the support bar 220 and the second surface 121 is brought in contact with the grinding wheel 210. In figure 5, the indicating means 130 indicates a grinding angle a of 15 degrees.

The first surface 111 may be configured to be brought in contact with the support bar 220 by having a shape that corresponds to the shape of the support bar 220. For example, the first surface 111 may be shaped to partially surround the support bar 220 such that the grinding angle setting device 100 may be suspended on the support bar 220, see in particular figures 2, 5 and 7. More precisely, the first surface 111 may be of a shape that allows the grinding angle setting device 100 to be placed or put on the grinding machine 200 without the need for a user to hold the angle setting device 100. Thus, the grinding angle setting device 100 may freely rest on the grinding angle setting device 100 while the user adjusts the support bar 220. The first surface is preferably not of a closed shape that would require the grinding angle setting device 100 to be threaded over the support bar 220.

If the first surface 111 is configured to be brought in contact with the support bar 220 by having a shape that corresponds to the shape of the support bar 220, the first surface 111 may be exactly positioned on the support bar 220. As will be described, the distance between the first and second surfaces 111, 121 is of importance when measuring or setting the grinding angle a, and thus the first surface 111 should preferably be exactly positioned on the support bar 220. When the first surface 111 has a shape that corresponds to the shape of the support bar 220, use of the grinding angle setting device 100 is simplified as the grinding angle setting device 100 may freely rest on the grinding machine 200 and as a user is less likely to incorrectly position the grinding angle setting device 100.

In the present example, the first surface 111 is essentially U-shaped, with the closed bottom of the U being directed upwards in use. It is to be apprehended, however, that other shapes are conceivable. The first surface 111 may for example be V-shaped or rectangular with an open side facing downwards in use. The shape of the first surface 111 is herein described in a side view of the grinding angle setting device 100 when in use, see e.g. figures 1 or 5.

The second surface 121 may be configured to be brought in contact with the grinding wheel 210 by having a shape and orientation that corresponds to the grinding surface of the grinding wheel 210. For example, the second surface 121 may comprise at least one essentially horizontal member that is adapted to rest on the peripheral surface of the grinding wheel 210. In this way, the grinding angle setting device 100 may be supported by the grinding wheel, see in particular figures 2, 5 and 7.

Thus, the first and second surfaces 111, 112 may be configured such that the angle setting device 100 may be positioned on the grinding machine 200 without the need for a user to hold the angle setting device 100 in place.

The second surface 121 may be shaped such it may easily be aligned with the circumference of the grinding wheel 210. For this reason, the second surface 121 may have a certain extension d (denoted in figures 4 and 6) as measured between two contact positions at which the second surface 121 makes contact with the grinding wheel 210. Said extension d should be sufficient to align the second surface 121 with the grinding wheel 210, for example art least 20-100 mm, preferably 30 to 80 mm. In the present example, the second surface 121 comprises two contact points 121a, 121b that are separated along the circumference of the grinding wheel 210. The two contact points 121a, 121b are in the present embodiment provided by two, in use, essentially horizontal members that may be referred to as a pair of contact bars. The contact bars are distanced d approximately 50 mm. In other embodiments, the second surface 121 may be curved such that it may contact and be aligned with the grinding wheel 210.

In the present example the second surface 121 is formed by a contact bracket 214 that is comprised in the second portion 120. The contact bracket 214 comprises a through hole for attachment, and the two above-mentioned contact bars that form the two contact points 121a, 121b.

As the radius of the grinding wheel 210 may vary, it may be desirable to take this variation into account when setting the grinding angle a. In the present embodiment of the grinding angle setting device 100, the position of the second surface 121 in relation to the second part 120 may be adjusted. This is obtained by the second surface 121 being attached to the second part 120 via an eccentric connection 215. In the present example, the contact bracket 214 is connected to the second portion via the eccentric connection 215. The eccentric connection may be tightened by a separate screw (see e.g. figure 3) and comprises an eccentrically positioned, circular protrusion that holds contact bracket 214. When the circular protrusion is rotated, the contact bracket 214 is displaced towards or away from the grinding wheel 210. A scale (not shown) may be provided such that the current grinding wheel radius can be selected.

In the current embodiment, the grinding angle setting device 100 comprises a first part 110 and a second part 120. Both are elongate and essentially plate-shaped. The first surface 111 is positioned of the first part 110 and the second surface 121 is positioned on the second part 120. Thus, the first part 110 is adapted for contacting the support bar 220 and the second part 120 is adapted for contacting the grinding wheel 210. As has been described, the second surface 121 is configured to be aligned with the circumference of the grinding wheel 210. Thus, the grinding angle setting device 100 is configured such that the second part 120 may be aligned with the circumference of the grinding wheel 210, more precisely aligned with the tangent line to the periphery of the grinding wheel 210 at a certain peripheral point, such as the contact point where the blade 300 is to be grinded.

As is illustrated, the first and second parts 110, 120 may be pivotally connected to one another. In this way, the first part 110 may be brought in contact with the support bar 220 and the second part 120 may be brought in contact with the grinding wheel 210. By pivoting the first and second parts 110, 120, the second part 120 may be aligned with the circumference of the grinding wheel 210. Alternatively, as describe below, the pivotal movement may be blocked by tightening an indicator lock screw 125 and the support bar 220 may be adjusted to align the second part 120 with the circumference of the grinding wheel 210.

In the present embodiment, the first and second parts 110, 120 are pivotally connected to one another by a hinge joint 112, 122. The hinge joint consists of a bushing 112 of the first part 110 and a bearing pin 122 of the second part 120. The bushing 112 receives the bearing pin 122 such that the first and second parts 110, 112 may be mutually rotated. The bushing 112 comprises a cylindrical inner bearing surface that extends orthogonal to the plate-shaped first part 110. The bushing 112 preferable does not extend all around the bearing pin 112, but comprises a cut-out along a portion of its circumference for the blade receiving surface 123 (described below). The bearing pin 122 protrudes orthogonal to the plate-shaped second part 120 and comprises a cylindrical outer bearing surface.

Figure 8 schematically illustrates method steps included in a method 400 of setting a grinding angle a for grinding a blade 300 held by a grinding jig 1. The method involves using the grinding angle setting device 100 of the present disclosure. As is to be apprehended, the steps need not be performed in the order described below.

In a fastening step 410, the blade 300 is clamped in the grinding jig 1. The grinding jig 1 may be of the type described herein, but also other grinding jigs are conceivable. However, the blade 300 should be fastened in the grinding jig with the edge of the blade 300 extending essentially orthogonal to the longitudinal axis Y of the grinding jig 1, see figures 2 and 10. Examples of other grinding jigs that may be used are disclosed in EP3722047B1 and EP2660005B1. The grinding angle setting device 100, the grinding machine 200 and the grinding jig 1 form a grinding system.

In an optional adjusting step 420, the length of the grinding angle setting device 100 is adapted to the length of the grinding jig 1 and the blade 300 clamped by the grinding jig 1. More precisely the distance between the first and second surfaces 111, 121 of the grinding angle setting device 100 are adjusted to the length of the jig 1 and the portion of the blade width that protrudes out from the jig 1. The corresponding features of the grinding angle setting device 100 are described below.

It is to be apprehended that not only the set position of the support bar 220 affects the grinding angle a, but also the combined length of the grinding jig 1 and the blade 300 clamped by the grinding jig 1. In another embodiment (not shown) of the grinding angle setting device, the distance between the first and second surfaces 111, 121 is not adjustable but instead the combined length of the grinding jig 1 and the blade 300 is to be adjusted to the grinding angle setting device. Thus, the arm 114 described below is optional.

In a bringing step 430, the first and second surfaces 111, 121 of the grinding angle setting device 100 are brought in contact with the support bar 220 and the grinding wheel 210, respectively. As has been described, the first surface 111 may be suspended on the support bar 220. This step is typically performed by the user simply placing the grinding angle setting device 100 such that it rests on the support bar 220 and the grinding wheel 210.

In an aligning step 440, the second surface 121 of the grinding angle setting device 100 is aligned with the grinding wheel 210. As has been described, this may be facilitated by there being provide two contact points 121a, 121b separated a distance d, whereby the aligning step 440 may be performed by the used pushing the grinding angle setting device 100 towards the grinding wheel 210. Depending on the weight of the grinding angle setting device 100 and the friction of the hinge joint 112, 122, the aligning step 440 may however require no action from the user as the second surface 121 may automatically align with the grinding wheel 210. In an obtaining step 450, the current grinding angle a may be read from the indicating means 130 of the grinding angle setting device 100. As is clear from e.g. figure 5, when the second surface 121 is aligned 440 with the grinding wheel 210, the second part 120 is moved such that the indicating means 130 indicates the current grinding angle a.

In an adjusting step 460, the support bar 220 may be adjusted in relation to the grinding wheel 210 unless the current grinding angle already equals the desired grinding angle a. As is illustrated e.g. in figure 7, the grinding machine 200 may comprise linear adjustment means 225 for straight, linear adjustment 460 of the support bar 220 in relation to the grinding wheel 210. In the current example, the support bar 220 is connected to the grinding machine housing by linear adjustment means in the form of sleeve-like connections that may be released and tightened by screws allowing adjustment of the support bar 220.

Other methods are also conceivable when using the grinding angle setting device 100 of the present disclosure. For example, instead of steps 430 to 460 the first and second parts 110, 120 may be pivoted until a desired grinding angle a is indicated by the indicating means 130. Next, the indicator lock screw 125 (denoted in figure 5) may be tightened to block movement between the first and second parts 110, 120. Then, the first and second surfaces 111, 121 may be brought in contact with the support bar 220 and the grinding wheel 210 and the support bar 220 may be adjusted until the second surface 121 is aligned with the grinding wheel 210. As is clear from the previously described method, the indicator lock screw 125 is however optional.

The grinding angle setting device 100 may be used with the indicator lock screw 125 untightened to measure a grinding angle a that corresponds to a set position of the support bar 220. For accurate measurement, the distance between the first surface 111 and the second surface 121 should first be adapted to the combined length of the grinding jig 1 and blade 300 to be grinded.

Referring e.g. to figures 4 and 6, the grinding angle setting device 100 may comprise a blade receiving surface 123. Thereby the above-described adjusting step 420 is facilitated. The blade 300 may rest securely against the blade receiving surface 123 while the length of the grinding angle setting device 100 is adjusted. In embodiments where the length of the grinding angle setting device 100 is not adjustable, the blade receiving surface 123 may instead be used for facilitating the adjustment of the combined length of the grinding jig 1 and the blade 300 to the grinding angle setting device 100. The latter procedure may be understood by studying figure 2, where the grinding jig 1 and the grinding angle setting device 100 are arranged next to one another in contact with the support bar 220.

As is shown, the blade receiving surface 123 preferably comprises an angle less than 180 degrees to secure the blade 300 at a defined position, in the present example the angle is approximately 90 degrees. The edge of the blade may abut against the vertex of the angle. The vertex of the angle points away from the first surface 111. The blade receiving surface 123 is preferably of a sufficient length to stably support the blade 300, such as at least 25 mm.

As is particularly clear from figure 4, in the present embodiment the blade receiving surface 123 coincides with the pivot axis A of the first and second parts 110, 120 of the grinding angle setting device 100. More precisely, the blade receiving surface 123 may be formed in the bearing pin 122.

The design of the grinding angle setting device 100 may be described by referring to a grinding end 100g and a support end 100s thereof, denoted in figures 4 and 6. The first surface I l l is located at the support end 100s and the second surface 121 is located at the grinding end 100g. Further, the pivot axis A and the blade receiving surface 123 are preferably located at the grinding end 100g.

The indicating means 130 of the present embodiment comprises a scale 131 on the first part 110 and an indicator 132 on the second part 120. In an alternative embodiment, the indicator 132 may be formed on the first part 110 and the scale 131 on the second part 120.

As is shown, the indicating means 130 located essentially at the first surface 111, at least closer to the first surface 111 than to the second surface 121. The first part 110 carrying the first surface 111 and the second part 120 carrying the second surface 121 may, as described above, be pivotally connected to one another essentially at the second surface 121. The indicating means 130 is thus preferably located at the support end 100s of the grinding angle setting device 100.

As has been mentioned, the length of the grinding angle setting device 100 may be adjusted 420 to the combined length of the grinding jig 1 and the blade 300. In other words, the distance between the first surface 111 and the second surface 121 may be adjustable. This may correspond to the length of the first part 110 being adjustable. In the present example, this is accomplished by the first part 110 comprising an extendable arm 114 (denoted in figures 3 and 4) on which the first surface 111 is positioned. The extendable arm 114 is slidably received in a groove of the first part 110 such that the extendable arm 114 may be pulled out from, and pushed into, the first part 110. The extendable arm 114 may be locked in any position by an arm lock screw 115.

Figure 7 shows the grinding angle setting device 100 when brought in contact with the support bar 220 and the honing wheel. As is shown in figure 7, and also in figure 3, the second contact surface 121 may optionally extend laterally from both sides of the second member 120. Thereby, the grinding angle setting device 100 may be positioned on either side of a grinding wheel or a honing wheel (compare figures 2 and 7). In the example of figures 3 and 7, there is provided a second pair of contact bars.

Turning to figure 9, a grinding jig 1 that is preferably used together with the grinding angle setting device 100 comprises a first clamp portion 10 and a second clamp portion 20. The grinding jig 1 is configured such that the blade 300 may be clamped by the first and second clamp portions 10, 20. In other words, the first and second clamp portions 10, 20 are selectively movable with respect to one another to clamp or release the blade 300. The grinding jig 1 further comprises an elongate, in the present disclosure essentially rodshaped, support portion 2 by means of which the grinding jig 1 may be supported onto the support bar 220 as is shown in figures 2 and 10. The support portion 2 extends along a longitudinal center axis Y of the grinding jig 1 and comprises a radial abutment surface 3 for abutment against the support bar 220. The radial abutment surface 3 has the same function as the radially extending stop of EP0214943B1 and the rear abutments of EP3722047B1.

The support portion 2 comprises a first support leg 2a and a second support leg 2b that extend in parallel next to one another from the radial abutment surface 3 to the first and second clamp portions 10, 20, respectively. As is illustrated, the first support leg 2a carries the first clamp portion 10. In the present examples, the first clamp portion 10 is attached to the first support leg 2a. With particular reference to figure 11, the first support leg 2a and the first clamp portion 10 comprise mutually adapted interfaces 7a, 10a such they may be rigidly attached to one another. In the present examples, the first clamp portion 10 is attached to the first support leg 2a by means of a screw connection. More precisely, a screw (countersunk bolt) 8a passes through the first support leg 2a into a threaded hole in the first clamp portion 10.

Similarly, the second support leg 2b carries the second clamp portion 20. In the present examples, the second clamp portion 20 is attached to the second support leg 2b. The second support leg 2b and the second clamp portion 20 comprise mutually adapted interfaces 7b, 10b such they may be rigidly attached to one another. In the present examples, the second clamp portion 20 is attached to the second support leg 2b by means of a screw connection. A screw (countersunk bolt) 8b passes through the second support leg 2b into a threaded hole in the second clamp portion 20.

In other embodiments (not shown) the first support leg 2a may carry the first clamp portion 10 by the first support leg 2a and the first clamp portion 10 being formed in one piece. Similarly, the second support leg 2b may carry the second clamp portion 20 by the second support leg 2b and the second clamp portion 20 being formed in one piece.

The first and second support legs 2a, 2b of the support portion 2 are fixed to one another at least at the radial abutment surface 3. In the present embodiments, the first and second support legs 2a, 2b are integral, i.e. formed in one piece. In other embodiments (not shown), the first and second support legs 2a, 2b may be attached to one another, e.g. glued or screwed to one another at least at the radial abutment surface 3. Since the first and second support legs 2a, 2b are fixed to one another at the radial abutment surface 3, the radial extension of the support portion 2 is fixed at the radial abutment surface 3. In other words, the thickness of the support portion 2 is constant at the radial abutment surface 3 when the first and second clamp portions 10, 20 are moved towards or away from one another.

The distal or front ends of the clamp portions 10, 20 may be referred to as the clamp end 4 of the grinding jig 1, i.e. the left end in figures 9 and 11 to 13. The proximal or rear ends of the clamp portions 10, 20 are in the present examples attached to the support portion 2. The end of the grinding jig 1 that is opposite to the clamp end 4 of the grinding jig 1 may be referred to as the rear end 5 of the grinding jig 1, i.e. the right end in figures 9 and 11 to 13. The reference numerals of the clamp end 4 and the rear end 5 are indicated in figure 12. Thus, the grinding jig 1 extends from a clamp end 4 to a rear end 5.

In the present embodiments, the distance from the clamp end 4 to the (rear) radial abutment surface 3 is approximately 80 percent of the length of the grinding jig 1. In other words, the length of the first support leg 2a together with the first clamp portion 10 corresponds to approximately 80 percent of the length of the grinding jig 1. The length of the second support leg 2b together with the second clamp portion 20 corresponds to approximately 80 percent of the length of the grinding jig 1. For ease of use and adaptability to various blade 300 shapes, this ratio may be at least 70 percent.

The first support leg 2a and the first clamp portion 10, and the second support leg 2b and the second clamp portion 20, respectively, may be configured to be attached to one another. The respective support leg 2a, 2b and clamp portion 10, 20 may be configured to be attached in a form fit manner. For attachment there between, the respective support leg 2a, 2b and clamp portion 10, 20 may comprise mutually complementing shapes. In other words, the first support leg 2a may be configured for a mating connection with the first clamp portion 10. The second support leg 2b may be configured for a mating connection with the second clamp portion 20. The proximal ends of the clamp portions 10, 20 may comprise attachment interfaces 10a, 10b of a shape that fits corresponding attachment interfaces 7a, 7b formed on or by the free end portions of the support legs 2a, 2b. The attachment interfaces 10a, 10b, 7a, 7b make possible a form fit (also referred to as a positive fit) between the clamp portions 10, 20 and the support legs 2a, 2b, respectively.

Referring in particular to figure 11, the first clamp portion 10 comprises a socket attachment interface 10a that is configured to receive a plug attachment interface 7a of the first support leg 2a. Similarly, the second clamp portion 20 comprises a socket attachment interface 10b that is configured to receive a plug attachment interface 7b of the second support leg 2b. When a plug attachment interface 7a, 7b is received by a corresponding socket attachment interface 10a, 10b in-plane P movement of the respective support leg 2a, 2b with respect the corresponding clamp portion 10, 20 is hindered. A snap-fit lock (not shown) or a screw connection (countersunk bolts 8a, 8b) as in the present examples may secure the plug and socket attachment interfaces 7a, 7b, 10a, 10b.

Thus, in the present embodiments the free end portion of the first support leg 2a forms the plug attachment interface 7a of the first support leg 2a. Said attachment interface 7a has the form of a trapezoid, as seen in a plan view (see figure 9 or 11). The longer one of the parallel sides of the trapezoid forms the end face of the first support leg 2a. As seen in a side view, the trapezoid tapers towards the end face. The inner face of the plug attachment interface 7a (lower face in figures 9 and 11) may comprise protuberances (two shown in figure 11) which are received in corresponding recesses of the socket attachment interface 10a. The plug and socket attachment interfaces of the second support leg 2b and second clamp portion 20 are in the present embodiments mirror symmetric (with respect to the center plane P) to the attachment interfaces of the first support leg 2a and first clamp portion 10.

As is shown, the rear end 5 of the grinding jig 1 may comprise or be composed of a handle portion 5h (reference numeral denoted in figure 12). It is however to be apprehended that it is the distance from the clamp end 4 (or more precisely from the edge of the blade 300) to the radial abutment surface 3 that is of importance to the grinding angle a, see e.g. figure 10.

The shape of the grinding jig 1 may generally be described as the one of a pair of tweezers. A pair of tweezers generally comprise a first lever and second lever connected at a fulcrum. The levers of the pair of tweezers may be referred to as arms. The first clamp portion 10 together with the first support leg 2a then correspond to the first lever of the imaginary pair of tweezers. The second clamp portion 20 together with the second support leg 2b correspond to the second lever of the imaginary pair of tweezers. In other words, the first clamp portion 10 together with the first support leg 2a form a first half of an imaginary pair of tweezers and the second clamp portion 20 together with the second support leg 2b form the second half of the imaginary pair of tweezers. Referring e.g. to figure 12 or 13, the radial abutment surface 3 is positioned where the levers meet, e.g. at the fulcrum of the imaginary pair of tweezers.

Similarly, the shape of the support portion 2 may generally be described as the one of a pair of tweezers. The first support leg 2a then corresponds to the first lever of the imaginary pair of tweezers and the second support leg 2b corresponds to the second lever of the imaginary pair of tweezers. Referring e.g. to figure 12 or 13, the radial abutment surface 3 is positioned where the levers (support legs 2a, 2b) meet, e.g. at the fulcrum of the imaginary pair of tweezers.

Turning in particular to figures 12 and 13, at least a portion of the radial abutment surface 3 extends perpendicular from the support portion 2 and around its circumferential. In the present embodiments, the radial abutment surface 3 is formed of a disc. The disc may have a flat side surface that forms the radial abutment surface 3, as is shown in EP3722047B1.

However, as is most apparent in figures 12 and 13, the transition 3t from the first support leg 2a to the radial abutment surface 3 may be rounded. Similarly, the transition 3t from the second support leg 2b to the radial abutment surface 3 may be rounded. Such rounded transitions, which may be denoted outer transitions 3t, may avoid or reduce stress concentrations when the first and second support legs are separated from one another, i.e. bent away from one another. Stress concentrations may also be avoided or reduced by a rounded inner transition 2t between the first and second support legs 2a, 2b. The inner transition 2t is essentially of a cylindrical shape.

In the present embodiments, the support bar 220 is of a circular cross-section, see e.g. figures 2, 5, 10 and 13. The above-mentioned outer rounded transition 3t may have a shape that fits the support bar 220. As is shown particularly in figure 13, the outer rounded transition 3t may have a radius of curvature that corresponds to the radius of the support bar 220.

The support portion 2 provides a respective axial support surface at the first and second support legs 2a, 2b. In normal use, the support portion 2 is supported both axially and radially against the support bar 220.

The first and second clamp portions 10, 20 are movable with respect to one another at the clamp end 4 such that the blade 300 may be releasably clamped there between. However, the first and second support legs 2a, 2b are fixed to one another at the radial abutment surface 3. Thus, even if the first and second clamp portions 10, 20 are movable with respect to one another at the clamp end 4, the first and second support legs 2a, 2b remain at the same distance from one another at the radial abutment surface 3.

Prior art grinding jigs, such as the ones known from EP0214943B1 and EP3722047B1, typically do not clamp a tool by the grinding jigs being bent. The first and second support legs 2a, 2b of the present disclosure may however be configured to be bent such that first and clamp portions 10, 20 are movable with respect to one another at the clamp end 4.

The section of the support portion 2 that is bent when the clamp portions 10, 20 are selectively separated or brought together to clamp or release the blade 300 may have an essentially circular cross-section. Thus, the first and second support legs 2a, 2b may at the section that is intended to be bent have essentially semi-circular cross-sections, see in particular figures 9 and 11. The first and second clamp portions 10, 20 comprise respectively a contact surface 10c, 20c for engaging a portion of the blade 300 when it is clamped. The contact surfaces 10c, 20c may be slightly concave such that the blade 300 is clamped between the lateral sides of the first and second clamp parts 10, 20. The first and second contact surfaces 10c, 20c are equidistant from the center plane P or center axis Y of the grinding jig 1.

The support portion 2 may alternatively be referred to as a shaft. The clamp portions 10, 10 may alternatively be referred to as clamp plates.

The support portion 2 may be made of plastic material, preferably fiber reinforced plastic material. The clamp portions 10, 20 may be made of metal, a preferred metal being zinc. The support portion 2 may in other embodiments be made of a resilient metal. When the support portion 2, as disclosed, is separate from the clamp portions 10 20, these portions may be referred to as parts. Thus, the grinding jig 1 may comprise an elongate support part 2, a first clamp part 10 and a second clamp part 20.

As is shown in figures 9 to 12, the grinding jig 1 may comprise front and rear radial abutments 3, 6a, 6b such that the grinding jig 1 may be moved back and forth the grinding means 210 across the support bar 220. Such a movement may generate a convex (knife) blade edge. Such a movement, especially a slower movement, may also generate a substantially straight blade edge. If the grinding jig 1 is not moved back and forth during grinding, a concave blade edge (of the same radius as the grinding wheel) may be generated. How similar abutments limit the movement of a grinding jig is described in EP3722047B1.

Referring to figure 11, the grinding jig 1 may comprise actuating means 30 to releasably force the first and second clamp portions 10, 20 towards one another to clamp the blade 300. Such actuating means may however be omitted and instead a separate clamp be used. E.g. a clamp that forms part of a grinding machine.

In the present embodiments, the actuating means 30 comprises a joining actuator 31 that is adapted to force the clamp portions 10, 20 towards one another by means of a joining screw connection. Further, the actuating means 30 comprises a separating actuator 35 that is adapted to force the clamp portions 10, 20 away from one another by means of a separating screw connection. As is illustrated, the separating actuator 35 is positioned between the joining actuator 31 and the radial abutment surface 3 where the first and second support legs 2a, 2b are fixed to one another. The clamp portions 10, 20 may comprise actuator interfaces for the joining actuator 31 and for the separating actuator 35.

In more detail, as is shown in figure 11 the joining actuator 31 may comprise a joining screw or bolt 32 and a joining nut 33. The shank of the joining bolt 32 may extend through the first clamp portion 10 and the head of the joining bolt 32 may rest against the first clamp portion 10. The joining nut 33 may be fixedly received in the second clamp portion 20 such that the clamp portions 10, 20 may be forced towards one another by a user turning the joining bolt 32. The joining bolt 32 and the joining nut 33 may be formed from another material than the clamp portions 10, 20, i.e. a material that is suitable for screw connections. In other embodiments (not shown), threads for the joining bolt 32 may be formed integrally in the second clamp portion 20 such that the joining nut 33 may be omitted.

The separating actuator 35 may comprise a separating screw or bolt 36 and a separating nut 37. The shank of the separating bolt 36 may extend through the first clamp portion 10 and abut against the second clamp portion 20. The separating nut 37 may be fixedly received in the first clamp portion 10 such that the clamp portions 10, 20 may be forced away from one another by a user turning the separating bolt 36. The separating bolt 36 and the separating nut 37 may be formed from another material than the clamp portions 10, 20, i.e. a material that is suitable for screw connections. In other embodiments (not shown), threads for the separating bolt 36 may be formed integrally in the first clamp portion 10 such that the separating nut 37 may be omitted.

The joining actuator 31 may in a fist clamping step be tightened such that the blade 300 is held between the clamp portions 10, 20. In a second step, the separating actuator 35 may be tightened to more firmly clamp the blade 300 through lever action. The separate joining actuator 31 and separating actuator 25 may also improve the ability of the grinding jig 1 to securely clamp blades 300 of various shapes and thicknesses. It is to be apprehended that since the first and second support legs 2a, 2b are fixed to one another at radial abutment surface 3, the actuating means 30 may in other embodiments (not shown) only comprise the joining actuator 31, i.e. the separating actuator 35 is optional. If the separating actuator 35 is omitted, the head of the joining bolt 32 may be enlarged as compared to the disclosed embodiment, such that a user may apply a sufficient torque to securely clamp the blade 300 without the use of a tool.

Figure 11 further shows a pair of helical compression springs that act to resiliently force the clamp portions 10, 20 (and thus the first and second support legs 2a, 2b) apart. The springs are held in place by a respective spring protrusion on the first clamp portions 10. The second clamp portions 20 comprises openings that receive the spring protrusion. The spring protrusions and corresponding openings may act as guiding means that guide the movement of the first and second clamp portions 10, 20 towards one another.

As is indicated in figure 13 (and also visible in figure 12) guiding means in the form of guide pins 15 may protrude from the first or second clamp portion 10, 20 and be received in guide pin openings in the other one of the second clamp portions 10, 20. Such guide pins 15 may guide the movement of the first and second clamp portions 10, 20 towards one another. In addition, two such guide pins 15 arranged at a distance from one another may assist in aligning the blade 300 perpendicular to the center axis Y of the grinding jig 1. The two guide pins 15 may be aligned along a line that is perpendicular to the center axis Y of the grinding jig 1.

It is to be apprehended that since the first and second support legs 2a, 2b are fixed to one another at radial abutment surface 3, the first and second support legs 2a, 2b may be resiliently forced apart and the helical compression springs may be omitted. For example, the first and second support legs 2a, 2b may be resilient or comprise resilient sections and may thereby be biased apart. The first and second support legs 2a, 2b may from manufacture be bent or curved away from one another.

As is clear from the above description of the grinding jig, especially in conjunction with the accompanying drawings thereof, the grinding jig 1 is configured such that the contact surfaces 10c, 20c are equidistant from the center plane P or center axis Y of the grinding jig 1 when the blade 300 is clamped between the contact surfaces 10, 20c. The grinding jig 1 may now be supported against the support bar 220 that is set at a desirable height dependent on the desired grinding angle a. The selected height of the support bar 220 together distance from radial abutment surface 3 to the edge of the blade 300 dictate the grinding angle a. The fact that the first and second support legs 2a, 2b are fixed to one another at the radial abutment surface 3 ensures that the grinding angle remains the same when the grinding jig 1 and the blade 300 are turned over.

Another advantage of the first and second support legs 2a, 2b being fixed to one another at the radial abutment surface 3 is that the height of the support bar 220 need not be adjusted when a blade 300 is exchanged for a blade of greater or smaller thickness, as long as the same portion of blade 300 protrudes out from the jig 1. In other words, the thickness of the blade 300 does not affect how the support bar 220 is to be positioned in relation to the grinding wheel 210 to obtain a desired grinding angle. The support bar 220 may e.g. be positioned using a computer program such as an app for a mobile phone without the thickness of the blade 300 being a required parameter. However, advantageously the grinding angle setting device 100 described herein is used to position the support bar 220.

The grinding jig of the present disclosure has a total length of approximately 140 mm, a typical range being 100 to 200 mm. The distance from the clamp end 4 to the rear radial abutment surface 3 is approximately 120 mm, a typical range being 80 to 180 mm. The distance between rear radial abutment 3 and the front abutments 6a, 6b is approximately 20 mm, a typical range being 15 to 30 mm. The width of the clamp portions 10, 20 is 45 mm, a typical range being 30 to 60 mm.

Modifications and other variants of the described embodiments will come to mind to one skilled in the art having benefit of the teachings presented in the foregoing description and associated drawings. Therefore, it is to be understood that the embodiments are not limited to the specific example embodiments described in this disclosure and that modifications and other variants are intended to be included within the scope of this disclosure.

For example, the first clamp part 10 and the first support leg 2a of the grinding jig 1 may be formed in one piece. Similarly, the second clamp part 20 and the second support leg 2b may be formed in one piece. In one embodiment, the first clamp part 10, the first support leg 2a, the second support leg 2b and the second clamp part 20 are all formed in one piece, i.e. integral.

Furthermore, although specific terms may be employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation. Therefore, a person skilled in the art would recognize numerous variations to the described embodiments that would still fall within the scope of the appended claims. As used herein, the terms “comprise/comprises” or “include/includes” do not exclude the presence of other elements or steps. Furthermore, although individual features may be included in different claims (or embodiments), these may possibly advantageously be combined, and the inclusion of different claims (or embodiments) does not imply that a certain combination of features is not feasible and/or advantageous. In addition, singular references do not exclude a plurality. Finally, reference signs in the claims are provided merely as a clarifying example and should not be construed as limiting the scope of the claims in any way.

Claims

1. A grinding angle setting device (100) for cooperative use with a grinding machine (200), the grinding machine (200) comprising a grinding means (210) and a support means (220) for supporting a grinding jig (1) holding a blade (300) to be grinded, the support means (220) being adjustable in relation to the grinding means (210) to set a grinding angle (a), wherein the grinding angle setting device (100) comprises

- a first surface (111) that is configured to be brought in contact with the support means (220),

- a second surface (121) that is configured to be brought in contact with the grinding means (210), and

- an indicating means (130) for indicating the grinding angle (a) that corresponds to the current position of the adjustable support means (220) in relation to the grinding means (210) when the first surface (111) is brought in contact with the support means (220) and the second surface (121) is brought in contact with the grinding means (210).

2. The grinding angle setting device (100) of claim 1, comprising a first part (110) on which the first surface (111) is positioned and a second part (120) on which the second surface (121) is positioned, wherein the first and second parts (110, 120) are pivotally connected to one another around a pivot axis (A).

3. The grinding angle setting device (100) of claim 2, wherein the first and second parts (110, 120) are pivotally connected to one another by a hinge joint (112, 122) comprising a bearing pin (122) that is rotatably journalled in a bushing (112).

4. The grinding angle setting device (100) of claim 3, wherein the first part (110) comprises the bushing (112) and the second part (120) comprises the bearing pin (122). The grinding angle setting device (100) according to any one of the preceding claims, comprising a blade receiving surface (123) that is configured to receive the blade (300) when held by the grinding jig (1), the blade receiving surface (123) preferably comprising an angle. The grinding angle setting device (100) of claim 5, wherein the blade receiving surface (123) is of a sufficient length to stably support the blade (300), the length of the blade receiving surface preferably being at least 25 mm. The grinding angle setting device (100) according to any one of the preceding claims, wherein the blade receiving surface (123) coincides with the pivot axis (A). The grinding angle setting device (100) according to any one of the preceding claims, wherein the bearing pin (122) comprises the blade receiving surface (123). The grinding angle setting device (100) according to any one of claims 2 to 8, wherein the indicating means (130) comprises a scale (131) on the first or second part (110, 120) and an indicator (132) on the other one of the first and second part (110, 120). The grinding angle setting device (100) of claim 9, wherein the indicating means (130) is located closer to the first surface (111) than to the second surface (121). The grinding angle setting device (100) according to any one of the preceding claims configured such that the distance between the first surface (111) and the second surface (121) is adjustable. The grinding angle setting device (100) according to claim 11 and any one of claims 2 to 11, wherein the length of the first part (110) is adjustable. 13. The grinding angle setting device (100) according to claim 12, wherein the first part (110) comprises an extendable arm (114) on which the first surface (111) is positioned.

14. The grinding angle setting device (100) of any preceding claim, wherein the first surface (111) is shaped to at least partially surround the support means (220) such that the grinding angle setting device (100) may be suspended on the support means (220), the first surface (111) preferably being U-shaped.

15. The grinding angle setting device (100) of any preceding claim, wherein the second surface (121) is configured to be aligned with the grinding means (210), e.g. by the second surface (121) comprising two contact points (121a, 121b) that are separated (d) along a circumference of the grinding means (210).

16. A grinding system comprising

- a grinding jig (1) for holding a blade (300) to be grinded,

- a grinding machine (200) compri sing a grinding means (210) and a support means (220) for supporting the grinding jig (1), the support means (220) being adjustable in relation to the grinding means (210) to set a grinding angle (a), and

- a grinding angle setting device (100) according to any of the preceding claims.

17. The grinding system of claim 16, wherein the grinding machine (200) comprises linear adjustment means (225) for straight, linear adjustment (460) of the support means (220) in relation to the grinding means (210).

18. The grinding system of claim 16 or 17, wherein the grinding jig (1) comprises

- a first and a second clamp portion (10, 20) that are movable with respect to one another to clamp the blade (300), and

- an elongate support portion (2) for supporting the grinding jig (1) onto the support means (220) of the grinding machine (200), the elongate support portion (2) comprising a first support leg (2a) carrying the first clamp portion (10) and a second support leg (2b) carrying the second clamp portion (20), wherein the elongate support portion (2) extends along a longitudinal center axis Y of the grinding jig (1) and comprises a radial abutment surface (3) for abutment against the support means (220) of the grinding machine (200), and the first and second support legs (2a, 2b) of the support portion (2) are fixed to one another at the radial abutment surface (3). A method (400) of setting a grinding angle (a) for grinding a blade (300) held by a grinding jig (1) using a grinding machine having a grinding means (210) and a support means (220) for supporting the grinding jig (1), the support means (220) being adjustable in relation to the grinding means (210) to set the grinding angle (a), and using a grinding angle setting device (100) according to any of the claims 1 to 15, the method comprising

- fastening (410) the blade (300) in the grinding j ig ( 1 ),

- bringing (430) the first surface (111) of the grinding angle setting device (100) in contact with the support means (220) and the second surface (121) of the grinding angle setting device (100) in contact with the grinding means (210),

- aligning (440) the second surface (121) of the grinding angle setting device (100) with the grinding means (210),

- obtaining (450) the current grinding angle (a) from the indicating means (130) of the grinding angle setting device (100), and

- adjusting (460) the support means (220) in relation to the grinding means (210) if the current grinding angle deviates from a desired grinding angle. The method of claim 19, further comprising adjusting (420) the distance between the first surface (111) and the second surface (121) of the grinding angle setting device (100) to the grinding jig (1) and the blade (300) held by the grinding jig (1).