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.
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 EP1818138B1 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.
U.S. Pat. No. 5,172,484A 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.
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
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:
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.
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
The grinding machine may also comprise a second grinding means 210 in the form of a cylindrical honing wheel, illustrated to the left in
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
As is shown in
In a grinding operation, as indicated in
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 α (denoted in
To set the grinding angle α, 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 α. The grinding angle α 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 α 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
Referring to
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
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 α, 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.
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
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
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 α. 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.
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.
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
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 α, 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 α may be read from the indicating means 130 of the grinding angle setting device 100. As is clear from e.g.
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 α. As is illustrated e.g. in
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 α is indicated by the indicating means 130. Next, the indicator lock screw 125 (denoted in
The grinding angle setting device 100 may be used with the indicator lock screw 125 untightened to measure a grinding angle α 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
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
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
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
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
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
Turning to
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
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
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
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
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
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
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
Turning in particular to
However, as is most apparent in
In the present embodiments, the support bar 220 is of a circular cross-section, see e.g.
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
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 1020, 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
Referring to
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
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.
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
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 α. 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 α. 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.
Number | Date | Country | Kind |
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2250303-1 | Mar 2022 | SE | national |
Filing Document | Filing Date | Country | Kind |
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PCT/EP2023/054593 | 2/23/2023 | WO |