Holding element for positioning and holding a blade to be sharpened in relation to a grinding surface of a grinding stone of a grinding machine

Abstract

The invention relates to a holding element (50) for positioning and holding a blade (28) to be ground in relation to a grinding surface (26) of a grinding wheel (24) rotatable about an axis of rotation (22) of a grinding machine (10), wherein the holding element (50) has a fastening section (52) designed for attachment to the grinding machine (10) and a holding section (54) which, when the fastening section (52) is attached to the grinding machine (10), is arranged near the grinding surface (26) of the grinding wheel (24) and on which the blade (28) to be ground is held, such that an edge (32) of the blade (28) to be ground is at a predetermined angle (α) on the grinding surface (26) of the grinding wheel (24). It is proposed that the fastening section (52) comprises a clamping element (66) which is designed for clamping the fastening section (52) to a pipe element (38) of the grinding machine (10) which extends at a distance from a grinding surface (26) of the grinding stone (24) and parallel to the axis of rotation (22) of the grinding stone (24), wherein the clamping element (66) comprises a receiving hole (68) for receiving the pipe element (38), wherein the pipe element (38) is clamped in the pipe element (38) exclusively by frictional engagement when the clamping element (66) is clamped to the pipe element (38) over its entire surface.

Description

[0001] The present invention relates to a holding element for positioning and holding a blade to be ground with respect to a grinding surface of a grinding stone of a grinding machine rotating about a rotation axis.The holding element has a fastening section which is designed for fastening to the grinding machine, and a holding section which, when the fastening section is fastened to the grinding machine, is arranged in the vicinity of the grinding surface of the grindstone and on which the blade to be ground is held, such that a cutting edge of the blade to be ground is at a predetermined angle on the grinding surface of the grindstone, and along which the blade to be ground can be moved back and forth during a grinding process - always held by the holding section - essentially parallel to a longitudinal extent of the cutting edge of the blade to be ground, such that the cutting edge of the blade to be ground can be moved back and forth over its entire longitudinal extent at the predetermined angle over the grinding surface of the grindstone.

[0002] Such a holding element is known, for example, from EP 2 883 655 A1. The fastening section comprises a hole for receiving a tubular element running parallel to and at a distance from the rotational axis of the grindstone of the grinding machine. The fastening section comprises a clamping element in the form of a screw clamp, with which the holding element can be fixed at a specific position along a longitudinal extent of the tubular element and at a specific angle about a longitudinal axis of the tubular element. The holding section is arranged at an end of the holding element opposite the fastening section. This comprises a clamp with two clamping arms, at least one of which is elastically flexible, between which the blade to be ground or sharpened is clamped.

[0003] The known holding element has several disadvantages: Inserting the blade between the clamping arms before sharpening is difficult, and there is a high risk of injury to the user. As the blade moves back and forth on the holding section during sharpening, the two clamping arms rub against the sides of the blade, which can lead to unsightly scratches on the blade surfaces. In addition, the elastic, flexible clamping arms cannot hold the blade sufficiently during sharpening, and the clamping effect of the clamping arms can diminish over time due to material fatigue and / or plastic deformation of the clamping arms. This also poses a risk of injury to the user and other bystanders if the blade is not adequately held by the holding element.

[0004] A generic holding element, in which the holding section of the holding element is designed such that the blade to be ground can rest against it, and in which the blade to be ground can be moved back and forth during the grinding process—always in contact with the holding section—essentially parallel to the longitudinal extent of the cutting edge of the blade to be ground, and in which at least one magnetic element is assigned to the holding section, which is designed to hold a blade to be ground made of ferromagnetic material to be ground against the holding section by means of magnetic force during the grinding process, is known, for example, from DE 691 25 358 T2. Furthermore, a similar holding element is known from JP 2011-104718 A.

[0005] Based on the described prior art, the present invention is based on the object of designing and developing a holding element of the type mentioned at the outset in such a way that the disadvantages mentioned are overcome and that it can be positioned and fastened to the pipe element with high precision in a particularly safe and reliable manner.

[0006] To achieve this object, a holding element having the features of claim 1 is proposed. In particular, starting from the holding element of the generic type, it is proposed that the fastening section comprises a clamping element which is designed for clamping the fastening section to a tubular element of the grinding machine which extends at a distance from a grinding surface of the grindstone of the grinding machine and parallel to the axis of rotation of the grindstone, wherein the clamping element comprises a receiving hole for receiving the tubular element, wherein the tubular element is clamped over its entire surface therein exclusively by means of frictional engagement when the clamping element is clamped to the tubular element.

[0007] Preferably, the holding section is arranged at an end of the holding element opposite the fastening section, and the holding element has a longitudinal extension extending between the fastening section and the holding section. Preferably, the at least one magnetic element is arranged in the holding section.

[0008] The design of the holding section, such that the blade to be sharpened simply rests against it and does not have to be clamped between two clamping arms, allows for simple, quick, and low-risk positioning of the blade against the holding section before the sharpening process. When the blade is sufficiently close to the holding section, it is automatically drawn to the holding section by magnetic force.

[0009] The whetstone is preferably disc-shaped and rotatable about a rotational axis, which is why it can also be referred to as a grinding wheel. During the grinding process and the reciprocating movement of the blade relative to the grinding surface of the whetstone parallel to the edge of the blade to be ground, the holding section rubs only on one side of the blade.

[0010] By applying a suitable protective coating to the holding section, at least in the areas that come into contact with one side of the blade, damage to the blade can be effectively prevented. The protective coating can be made of plastic, rubber, felt, cotton, foam, or similar materials. The protective coating is particularly preferably made of a softer material than the ferromagnetic metal of the blade.

[0011] The protective coating is preferably applied to the holding section in an interchangeable manner. The protective coating can, for example, be designed as a cover made of an elastic material, e.g., cotton or a similar woven material or fabric. The cover has a diameter that is slightly smaller than the inside width of the holding section, so that the cover, when applied to the holding section, rests fully on the holding section, particularly in the areas that come into contact with one side of the blade. Grinding chips created when grinding the cutting edge pass through the fabric of the cover to the holding section, where they are held by the magnetic force. The soft fabric of the cover is thus arranged between the grinding chips and the blade, preventing the chips from scratching the sides of the blade when the blade is moved back and forth on the holding section.

[0012] Finally, by arranging particularly strong or multiple magnetic elements, the magnetic force can be adjusted to such a level that the blade to be sharpened is held securely and reliably to the holding section by magnetic force during the sharpening process.

[0013] The blade with the edge to be sharpened is, for example, part of a knife. However, it can also be part of any other object to be sharpened, such as a hatchet, axe, chisel, etc.

[0014] According to an advantageous development of the invention, it is proposed that the at least one magnetic element comprises a permanent magnet and / or an electromagnet. In particular, it is proposed that the at least one magnetic element comprises a neodymium magnet. Preferably, four or more separate neodymium magnets are arranged in the holding section.

[0015] According to a preferred embodiment of the invention, it is proposed that the holding section has a flat contact surface against which the blade to be ground comes to rest and along which the blade to be ground can be moved back and forth during the grinding process - always in contact with the contact surface - essentially parallel to the longitudinal extent of the cutting edge of the blade to be ground. During the grinding process, the blade preferably rests with one of its sides completely on the contact surface. Preferably, a plurality of magnetic elements are provided distributed over the contact surface. In this way, the holding element can be used for blades of different sizes. In addition, larger blades are held with a greater magnetic force by a larger number of magnetic elements arranged on or below the contact surface.

[0016] Advantageously, the at least one magnetic element is assigned to the contact surface, preferably the at least one magnetic element is arranged set back from the contact surface, particularly preferably the at least one magnetic element is arranged on the contact surface concealed by a thin protective layer of rubber or plastic, wherein the protective layer preferably merges flush into the contact surface.

[0017] Preferably, a portion of the holding section that comes into contact with the blade to be ground is made of rubber or plastic. This portion of the holding section can also be made of other materials that are softer than the ferromagnetic metal of the blade. Particularly preferably, the material of the portion of the holding section that comes into contact with the blade to be ground also has a low coefficient of friction, such as PTFE. This allows the blade to be moved back and forth more easily against the contact surface during the grinding process.

[0018] The fastening section can be fastened to the grinding machine or a part thereof in any desired manner. Preferably, the fastening section is detachably fastened to the grinding machine or a part thereof. Particularly preferably, the fastening section is adjustably fastened to the grinding machine or a part thereof. In this way, the predeterminable angle and / or a distance of the holding section from the grinding surface of the grinding wheel of the grinding machine can be adjusted. It is proposed that the fastening section for fastening the holding element is designed at a predeterminable angle to a part of the grinding machine, such that the holding section is aligned at a predefined angle and / or a predefined distance from the grinding surface of the grinding wheel of the grinding machine.

[0019] The part of the grinding machine to which the fastening section of the holding element is attached is preferably adjustable relative to the grinding surface of the grinding wheel on the grinding machine. In this way, the holding section of the attached holding element can be aligned at a predeterminable angle and / or a predeterminable distance relative to the grinding surface of the grinding wheel of the grinding machine.

[0020] Alternatively, it is conceivable for the holding element to have an alignment section arranged between the fastening section and the holding section and designed to adjust the angle and / or distance of the holding section from the grinding surface of the grinding wheel of the grinding machine and to maintain the adjusted angle and / or distance during the grinding process. This configuration makes it possible to always fasten the fastening section in the same position and orientation to the grinding machine or a part thereof, and yet still adjust the angle and / or distance of the holding section from the grinding surface of the grinding wheel of the grinding machine depending on the blade to be ground. The alignment section can have a pivot joint that connects the fastening section to the holding section and can be adjusted and fixed at a specific angle.Alternatively or additionally, the alignment section can have a sliding element extending along the longitudinal extent between the fastening section and the holding section, which allows adjustment of a distance between the fastening section and the holding section and fixation at the adjusted distance. This allows the distance of the holding section to the grinding surface of the grinding wheel of the grinding machine to be adjusted separately.

[0021] Finally, it is proposed that the fastening section comprise a clamping element, in particular in the form of a screw clamp, which is designed for clamping the fastening section to a part of the grinding machine, in particular to a tubular element extending at a distance from and parallel to the rotational axis of the grinding stone of the grinding machine. In this sense, the fastening section can have a hole for receiving the tubular element extending at a distance from and parallel to the rotational axis of the grinding stone of the grinding machine. The hole preferably has a larger inner diameter than the outer diameter of the tubular element.The tubular element is inserted into the receiving hole and secured by means of a clamping element in the form of a screw clamp, so that the holding element is fixed at a specific position along a longitudinal extension of the tubular element and at a specific angle around a longitudinal axis of the tubular element.

[0022] The clamping element comprises, for example, at least one screw that can be screwed into a threaded bore extending radially to a longitudinal axis of the tubular element from outside the fastening section into the receiving hole. When the screw is tightened, the tip of the screw presses radially against the outer surface of the tubular element, such that the fastening section is fixed to the tubular element by frictional engagement. However, the clamping element preferably comprises at least one screw extending at a distance from and perpendicular to the longitudinal axis of the tubular element. When the screw is tightened, the cross-section of the receiving hole decreases and the tubular element is clamped therein over its entire surface. This has the advantage of preventing damage to the outer surface of the tubular element, e.g., by scratches or notches.

[0023] On the fastening section, a scale is preferably provided around at least part of the receiving hole, which scale indicates various angles at which the holding element can be secured to the tubular element by means of the clamping element. For this purpose, a notch or other marking can be provided on the tubular element which, depending on the angle of the holding element on the tubular element, points to a specific scale mark on the scale that corresponds to the set angle. In this way, the holding element and the blade to be sharpened held thereon can be easily and quickly adjusted to a desired angle relative to the grinding machine or a part thereof, in particular the tubular element. In the desired angular position, the holding element is then secured to the grinding machine or a part thereof, in particular to the tubular element, for example by tightening the clamping element.Numerical values ​​can be assigned to the scaling, corresponding to the different adjustable angles.

[0024] The fastening section of the holding element is preferably milled from a single block of metal, in particular aluminum, or another material. However, it would also be conceivable for the fastening section to be sintered, cast, or injection-molded from a metal or another material. The holding section preferably comprises a separate contact element which comprises the at least one magnetic element and is fastened to the remaining holding element. The contact element can form the bearing surface of the holding section. It is preferably made of an injection-molded and / or cast plastic material. To accommodate the at least one magnetic element, at least one recess is formed on one side of the contact element with which it is fastened to the fastening section of the holding element. Preferably, a separate recess is provided for each magnetic element. Preferably, a magnetic element is arranged in the recess by means of a press fit.After the contact element is attached to the remaining retaining element, the receiving openings in the recesses are closed. The contact element can be attached to the remaining retaining element using clips, snaps, adhesives, or press-fitting, for example.

[0025] According to an advantageous development of the invention, it is proposed that the holding element has a support section which is arranged opposite the holding section at a distance from the latter, such that a receiving gap is formed between the support section and the holding section, in which at least part of the blade to be sharpened is received during the grinding process. This has the advantage that the blade to be sharpened is not abruptly thrown away from the contact surface by the rotating grindstone during the grinding process, contrary to the magnetic holding force, and thus cannot injure bystanders, including the user. Instead, the blade which becomes detached from the contact surface strikes the support section, is caught by it and prevented from being thrown away. Rather, the blade remains in the receiving gap formed between the holding section and the support section.This significantly improves operating safety and comfort.

[0026] If the holding section has a flat contact surface against which the blade to be ground rests and along which the blade to be ground can be moved back and forth during the grinding process, the support section preferably has a support surface facing the contact surface. The support surface preferably extends parallel to the contact surface. The blade rests against this support surface if it is abruptly thrown away from the contact surface by the rotating grindstone during the grinding process, against the magnetic holding force.

[0027] Preferably, the support surface of the support section has a smaller surface area than the contact surface of the holding section. In particular, the support surface has a smaller depth than the contact surface in a direction transverse to the longitudinal extent of the blade to be ground in its position during the grinding process. This has the advantage that the holding element can be easily positioned above the grindstone, and the blade to be sharpened, held by the holding element, can be positioned at a desired angle on the grinding surface of the grindstone without the support section colliding with the grindstone.

[0028] According to another advantageous development of the invention, a demagnetization surface is formed on the rear side of the holding section, on which a magnetic force acts that opposes the magnetic force acting on the contact surface of the holding section, and on which the ground blade can be moved back and forth after the grinding process. The grinding process and / or the back and forth movement of the blade made of ferromagnetic material in the magnetic field acting on the contact surface, which holds the blade to the contact surface, can magnetize the blade, which is sometimes perceived as disruptive when the blade is used as intended.By moving the blade back and forth on or near the demagnetization surface, where an oppositely directed magnetic field acts, following the grinding process, this magnetization of the blade can be reduced or even completely compensated before the blade is put to its intended use.

[0029] To protect the blade to be demagnetized on the back of the holding section from scratches, a protective layer made of a soft material can be applied or arranged on the back, at least temporarily for the duration of the demagnetization. The protective layer is applied at least in those areas of the back that come into contact with one side of the blade to be sharpened during demagnetization. This can effectively prevent damage to the blade. Preferably, the protective layer is made of a softer material than the ferromagnetic metal of the blade. The protective layer can, for example, comprise a soft plastic, rubber, felt, cotton, other textile material, foam, or similar. Preferably, a textile rubber band is pulled over the holding section, covering at least the back of the holding section, at least temporarily. The textile rubber band can cover both the contact surface and the demagnetization surface.Alternatively, the protective layer can also be glued to the back of the holding section or attached in some other way.

[0030] Preferably, the protective layer is applied to the holding section in a replaceable manner. The protective layer can be designed, for example, as a cover made of an elastic material, such as a textile fabric, cotton, or a similar woven material. The cover has a diameter that is slightly smaller than the inside width of the holding section, so that the cover applied to the holding section rests fully on the holding section, particularly in the areas that come into contact with one side of the blade to be sharpened and / or demagnetized. Grinding chips created during grinding of the cutting edge pass through the fabric of the cover to the holding section, where they are held by the magnetic force.The soft fabric of the cover is thus arranged between the grinding chips and the blade, preventing the chips from scratching the sides of the blade when the blade is moved back and forth on the holding section.

[0031] The oppositely directed magnetic field acting on the demagnetization surface is preferably generated by at least one magnetic element. This magnetic element can be the same one that also generates the magnetic force acting on the contact surface of the holding section. The at least one magnetic element is preferably designed to generate a magnetic force directed in a first direction on a front side and / or the contact surface of the holding section and simultaneously to generate a magnetic force directed in a second direction opposite to the first direction on the rear side and / or the demagnetization surface of the holding section.

[0032] Particularly preferably, the at least one magnetic element is designed and / or arranged in or on the holding element such that an amount of the oppositely directed magnetic force acting on the demagnetization surface is smaller than an amount of the magnetic force acting on the contact surface of the holding section, with the aid of which the blade to be ground made of ferromagnetic material is held on the holding section during the grinding process.

[0033] Further features and advantages of the present invention are explained in more detail below with reference to the figures. It is emphasized that individual features shown in the figures may be essential to the invention in their own right, even if this is not explicitly mentioned in the description. Furthermore, features shown in the figures may be combined with one another in any desired manner, even if such a combination is not shown in the figures and / or not mentioned in the description. The figures show: Fig. 1 a grinding machine with a holding element according to the invention in a side view; Fig. 2 the grinding machine Fig. 1 in a front view; Fig. 3 a fastening section of the holding element according to the invention in a longitudinal section; Fig. 4 a contact element of the holding element according to the invention in a perspective view; Fig. 5 shows a holding element according to the invention in another embodiment in a sectional view; and Fig. 6 the retaining element Fig. 5 without separate system element in a perspective view.

[0034] In Fig. 1 and Fig. 2 shows a grinding machine 10 known per se from the prior art. This comprises a housing 12 with which it stands on a base 14, e.g., a table or workbench. The housing 12 is made, for example, of plastic, metal, or another suitable material. An electric motor 16 is arranged inside the housing 12 and can be supplied with electrical energy via the mains and / or by means of rechargeable batteries. The motor 16 drives a machine shaft 18 and causes it to rotate in a direction 20 about its longitudinal axis 22. A grinding stone 24 is rotatably fastened to an end of the machine shaft 18 protruding from the housing 12. This grinding stone is disc-shaped, with an axis of rotation of the grinding stone 24 corresponding to the longitudinal axis 22 of the machine shaft 18, and an outer peripheral surface forming a grinding surface 26. The machine shaft 18 and the grinding stone 24 attached to it rotate in one direction 25.As will be explained in more detail below, a blade 28 of an object to be sharpened, for example a knife 30, an axe, a hatchet, a chisel or the like, can be guided with its cutting edge 32 parallel to a transverse extension of the grinding surface 26 and parallel to a longitudinal extension of the blade 28 or the cutting edge 32 over the grinding surface 26 in order to sharpen the object 30.

[0035] A gearbox 34 and / or a clutch may be provided between the motor 16 and the machine shaft 18. A similar gearbox and / or clutch could be provided between the machine shaft 18 and the grinding stone 24. Electrical switches and / or controls for switching the motor 16 on and off and / or for adjusting a speed of the motor 16 are shown in Fig. 1 and Fig. 2 not shown.

[0036] A tubular element 38 is attached to an upper section 36 of the housing 12 via two struts 40. Of course, only one strut 40 or more than two struts 40 can be provided. Likewise, the tubular element 38 can be attached to the housing 12 or another part of the grinding machine 10 in another way. The tubular element 38 and / or the struts 40 are preferably made of a solid metal material, e.g., stainless steel, and preferably have a circular cross-section with a diameter of at least 10 mm, particularly preferably 12 mm. Other cross-sections of the tubular element 38 are also conceivable. A longitudinal axis 42 of the tubular element 38 runs at a distance from and substantially parallel to the rotational axis 22 of the grinding stone 24.

[0037] A specially designed holding element according to the invention for positioning and holding the blade 28 to be ground relative to the grinding surface 26 of the grindstone 24 of the grinding machine 10 is designated in its entirety by the reference numeral 50. The holding element 50 has a fastening section 52, which is designed for attachment to the grinding machine 10 or a part thereof, e.g., to the tubular element 38, and a holding section 54, which, when the fastening section 52 is attached to the grinding machine 10, is arranged near the grinding surface 26 of the grindstone 24 and on which the blade 28 to be ground is held. When the blade 28 is held on the holding section 54, the cutting edge 32 of the blade 28 to be ground is at a predeterminable angle α on the grinding surface 26 of the grindstone 24.In addition, the blade 28 held on the holding section 54 can be moved back and forth along the holding section 54 during a grinding process - always held by the holding section 54 - essentially parallel to a longitudinal extent of the cutting edge 32 of the blade 28 to be ground in a direction 55, so that the cutting edge 32 can be moved back and forth over its entire longitudinal extent at the predeterminable angle α on the grinding surface 26 of the grindstone 24 and can be sharpened in this way.

[0038] The holding section 54 of the holding element 50 according to the invention is designed such that the blade 28 to be ground can rest against it, and such that the blade 28 to be ground can be moved back and forth in the direction 55 during the grinding process—always in contact with the holding section 54—essentially parallel to the longitudinal extent of the cutting edge 32 of the blade 28 to be ground. Furthermore, the holding section 54 is assigned at least one magnetic element 56, which is designed to hold a blade 28 to be ground made of a ferromagnetic material to the holding section 54 by means of magnetic force during the grinding process.

[0039] In the example shown, the holding section 54 is arranged at an end of the holding element 50 opposite the fastening section 52. Furthermore, the holding element 50 shown has a longitudinal extension that extends between the fastening section 52 and the holding section 54. The at least one magnetic element 56 is preferably arranged in the holding section 54.

[0040] The design of the holding section 54 such that the blade 28 to be ground merely comes into contact therewith (and is not clamped between two clamping arms as in the prior art) enables a simple, quick and low-risk arrangement of the blade 28 in contact with the holding section 54 before the grinding process. When the blade 28 comes sufficiently close to the holding section 54, the blade 28 made of ferromagnetic material is automatically drawn to the holding section 54 by means of magnetic force and is held there securely and reliably.

[0041] During the grinding process and the back and forth movement of the blade 28 to be ground relative to the grinding surface 26 of the grindstone 24 parallel to the extension of the cutting edge 32 in the direction 55, the holding section 54 rubs only on one side of the blade 28.

[0042] By providing a suitable protective coating 58 of the holding section 54, at least in the areas that come into contact with one side of the blade 28, damage to the blade 28 can be effectively prevented (cf. Fig. 4). The protective coating 58 can comprise, for example, plastic, rubber, felt, cotton, foam, or similar. Preferably, the protective coating 58 is made of a softer material than the ferromagnetic metal of the blade 28.

[0043] Particularly preferably, the protective coating 58 is applied replaceably to the holding section 54. The protective coating 58 can be designed, for example, as a cover (not shown) made of an elastic material, e.g., cotton or a similar woven material or fabric. The cover has a diameter that is slightly smaller than the inside width of the holding section 54, so that the cover, when applied to the holding section 54, fits snugly and over the entire surface of the holding section 54, particularly in the areas that come into contact with one side of the blade 28. Grinding chips that arise when grinding the cutting edge 32 pass through the fabric of the cover to the holding section 54, where they are held by the magnetic force.Thus, the soft fabric of the cover is arranged between the grinding chips and the blade 28, so that scratching of the sides of the blade 28 by the chips when the blade 28 is moved back and forth on the holding section 54 is prevented.

[0044] By arranging particularly strong or multiple magnetic elements 56, the magnetic force can be adjusted to such a strength that the blade 28 to be ground is held securely and reliably on the holding section 54 by magnetic force during the grinding process. Preferably, the at least one magnetic element 56 comprises a permanent magnet. In particular, it is proposed that the at least one magnetic element 56 comprises a neodymium magnet. Preferably, four or more separate neodymium magnets 56 are arranged in the holding section 54 (cf. Fig. 2 and Fig. 4).

[0045] It is particularly preferred if a flat contact surface 60 is formed on the holding section 54, against which the blade 28 to be ground comes to rest and along which the blade 28 to be ground can be moved back and forth in the direction 55 during the grinding process - always in contact with the contact surface 60 - essentially parallel to the longitudinal extent of the cutting edge 32 of the blade 28 to be ground. During the grinding process, the blade 28 preferably rests with one of its sides completely on the contact surface 60. Preferably, a plurality of magnetic elements 56 are arranged distributed over the contact surface 60. In this way, the holding element 50 can be used for blades 28 of different sizes. In addition, larger blades 28 are held with a greater magnetic force by a larger number of magnetic elements 56 arranged on or below the contact surface 60.

[0046] Preferably, the at least one magnetic element 56 is arranged concealed by a thin protective layer of rubber or plastic beneath the contact surface 60, wherein the protective layer preferably merges flush into the contact surface 60 or forms the contact surface 60 itself.

[0047] In the embodiment shown in the figures, the contact surface 60 is formed by a separate contact element 62 (cf. Fig. 4) which is fastened by its rear side 64 to the remaining holding element 50', for example by gluing. Alternatively, the contact element 62 can also be fastened to the remaining holding element 50' by clipping, locking, or press fitting. To accommodate the at least one magnetic element 56, at least one recess 76 can be formed on the rear side 64 of the contact element 62. A separate recess 76 is preferably provided for each magnetic element 56. Preferably, a magnetic element 56 is arranged in the corresponding recess 76 by means of a press fit. Alternatively, the magnetic element 56 can also be fastened in the recess 76 by gluing, locking, or similar. After the contact element 62 has been fastened to the remaining holding element 50', the receiving openings of the recesses 76 are closed.

[0048] The remaining holding element 50' is preferably milled from a single block of metal, in particular aluminum, a metal alloy, or one or more other materials. Of course, it can also be sintered or cast from a metal or a metal alloy. In the example shown, the remaining holding element 50' comprises the fastening section 52 and a supporting part 54' of the holding section 44 (see FIG. Fig. 1). The remaining support element 50' has an L-shape when viewed from the side. Of course, the remaining support element 50' could also have a different shape when viewed from the side, for example, an I-shape that extends exclusively along the longitudinal extent of the support element 50.

[0049] The contact element 62 and its front side, opposite the rear side 64, form the part of the holding element 50 that comes into contact with the blade 28 to be ground during the grinding process. The contact element 62 is preferably made of plastic. Particularly preferably, the contact surface 60 is coated with or made of a material with a low coefficient of friction, e.g., PTFE or another suitable plastic. This allows the blade 28 to be moved back and forth in the direction 55 more easily in contact with the contact surface 60 during the grinding process.

[0050] The fastening section 52 can be fastened in any manner to the grinding machine 10 or a part thereof, for example, the tubular element 38. Preferably, the fastening section 52 is detachably fastened to the grinding machine 10 or the part 38 thereof. Particularly preferably, the fastening section 52 is adjustably fastened to the grinding machine 10 or a part 38 thereof. In this way, the predeterminable angle α and / or a distance of the holding section 54 from the grinding surface 26 of the grinding wheel 24 of the grinding machine 10 can be adjusted.

[0051] As shown by the Fig. 1, the fastening section 52 for fastening the holding element 50 is arranged at a predeterminable angle β on a part 38 of the grinding machine 10, so that the holding section 54 is aligned at the predefined angle α and / or the predefined distance from the grinding surface 26 of the grinding wheel 24 of the grinding machine 10. To vary the angle β, the holding element 50 is adjustable, in particular rotatable, in a direction 51 about a longitudinal axis 42 of the tubular element 38.

[0052] The part 38 of the grinding machine 10 to which the fastening section 52 of the holding element 50 is attached is preferably itself adjustable, in the example shown, height-adjustable in the direction 60, with respect to the grinding surface 26 of the grinding wheel 24 and can be fixed at the desired height on the housing 12 or another part of the grinding machine 10. In this way, the holding section 54 of the holding element 50 attached to the part 38 of the grinding machine 10 can be aligned at the predeterminable angle α and / or the predeterminable distance with respect to the grinding surface 26 of the grinding wheel 24 of the grinding machine 10.

[0053] In the example shown, the tubular element 38 is positioned approximately 50 mm above the grinding surface 26 of the grinding wheel 24. With the given configuration of the holding element 50, the holding section 54 of the holding element 50 is then arranged at an angle α = 15° with respect to the grinding surface 26 of the grinding wheel 24. The distance of the holding section 54 or a distal edge of the contact surface 60 from the grinding surface 26 is relatively small and selected to be just large enough for the grinding wheel 24 to rotate relative to the rotation axis 22 without touching the holding section 54 and / or the contact surface 60.

[0054] Alternatively, in an embodiment not shown, it would also be conceivable for the holding element 50 to have an alignment section which is arranged between the fastening section 52 and the holding section 54 and is designed to adjust the angle α and / or the distance of the holding section 54 to the grinding surface 26 of the grinding wheel 24 of the grinding machine 10 and to maintain the adjusted angle α and / or distance during the grinding process.

[0055] As in Fig. 3, the fastening section 52 preferably has a clamping element 66, in particular in the form of a screw clamp. The clamping element 66 is designed for clamping the fastening section 52 to a part of the grinding machine 10, in particular to the tubular element 38 extending parallel to and at a distance from the rotational axis 22 of the grinding stone 24 of the grinding machine 10. In this sense, the fastening section 52 can have a hole 68 for receiving the tubular element 38. The hole 68 preferably has a slightly larger inner diameter than the outer diameter of the tubular element 38. A gap 70 extends radially outward from the receiving hole 68.After the tubular element 38 has been inserted into the receiving hole 68, it is secured by means of the clamping element 66 so that the holding element 50 is releasably fastened at a specific position along a longitudinal extent of the tubular element 38, preferably above the grinding stone 24, and at a specific angle β about a longitudinal axis 42 of the tubular element 38.

[0056] The clamping element 66 preferably comprises at least one screw 72 extending at a distance from and perpendicular to the longitudinal axis 42 of the tubular element 38. This screw 72 is inserted into a hole 73 in the fastening section 52, which extends through the gap 70. The screw 72 is then screwed with its external thread into a section 74 of the hole 73 with an internal thread. When the screw 72 is tightened, the cross-section of the gap 70 and thus also the diameter of the receiving hole 68 decreases, so that the tubular element 38 is clamped therein over its entire surface exclusively by means of frictional engagement. This has the advantage of preventing damage to an outer surface of the tubular element 38, for example by scratches or notches.

[0057] On the fastening section 52, a scale 86 is preferably provided around at least part of the receiving hole 68, indicating various angles at which the holding element 50 can be secured to the tubular element 38 by means of the clamping element 66. For this purpose, a notch 88 or other marking can be provided on the tubular element 38, which, depending on the angle of the holding element 50 relative to the tubular element 38, points to a specific scale mark on the scale 86, which corresponds to the set angle. In this way, the holding element 50 and the blade 28 to be sharpened held thereon can be easily and quickly adjusted to a desired angle relative to the grinding machine 10 or a part thereof, in particular the tubular element 38. In the desired angular position, the holding element 50 is then secured to the grinding machine 10 or a part thereof, in particular to the tubular element 38, for example by tightening the clamping element 66.The scale 86 can be assigned numerical values ​​that correspond to the various adjustable angles.

[0058] In an alternative embodiment not shown, the clamping element 66 comprises at least one screw that can be screwed into a threaded bore extending radially to the longitudinal axis 42 of the tubular element 38 from outside the fastening section 52 into the receiving hole 68. When the screw is tightened, a tip of the screw presses radially against the outer surface of the tubular element 38, so that the fastening section 52 is fixed to the tubular element 38 by means of frictional engagement and positive engagement (when the tip of the screw digs into the outer surface of the tubular element 38).

[0059] The remaining retaining element 50' (retaining element 50 without contact element 62) is preferably milled from a single block of metal, in particular aluminum, a metal alloy, or one or more other materials. The remaining retaining element 50' comprises at least the fastening section 52. In the example shown, the remaining retaining element 50' also comprises the supporting section 54' of the retaining element 54. The supporting section 54' is formed integrally with the fastening section 52.

[0060] As shown by the Fig. 5 and Fig. As can be seen in Figure 6, the holding element 50 has a support section 78, which is arranged opposite the holding section 54 at a distance therefrom, so that a receiving gap 80 is formed between the support section 78 and the holding section 54, into which at least a portion of the blade 28 to be ground is received during the grinding process. As a result, the blade 28 to be ground can be guided during the grinding process by the rotating grindstone 24 (see Figure 6). Fig. 1) cannot be abruptly propelled from the contact surface 60 against the magnetic holding force, and bystanders, including the user, can be protected from injury by the blade 28 and / or its cutting edge 32. Instead, if the blade 28 were to detach from the contact surface 60, it would strike the support section 78, which would catch it and prevent it from being propelled away. Rather, the blade 28 remains in the receiving gap 80 formed between the holding section 54 and the support section 78.

[0061] If the holding section 54 has a flat contact surface 60 against which the blade 28 to be ground comes to rest and along which it can be moved back and forth during the grinding process, the support section 78 preferably has a support surface 82 which faces the contact surface 60 (cf. Fig. 5). The support surface 82 preferably extends parallel to the contact surface 60. The blade 28 comes to rest against this support surface 82 if, during the grinding process, it is abruptly thrown away from the contact surface 60 by the rotating grindstone 24 against the magnetic holding force.

[0062] Preferably, the support surface 82 of the support section 78 has a smaller surface area than the contact surface 60 of the holding section 54. In particular, the support surface 82 has a smaller depth than the contact surface 60 in a direction transverse to the longitudinal extent of the blade 28 to be ground and / or transverse to the direction of the back and forth movement of the blade 28 during the grinding process. This has the advantage that the holding element 50 can be easily positioned above the grindstone 24 (cf. Fig.1) and the blade 28 to be sharpened, which is held magnetically by the holding element 50, can be positioned at a desired angle α on the grinding surface 26 of the grindstone 24 without the support section 78 being able to collide with the grindstone 24.

[0063] According to another embodiment, it is proposed that a demagnetization surface 84 be formed on a rear side of the holding section 54, on which a magnetic force acts that is opposite to the magnetic force acting on the contact surface 60 of the holding section 54. After the grinding process, the ground blade 28 can be moved back and forth on the demagnetization surface 84, preferably parallel to the longitudinal extent of the blade 28. Due to the grinding process and / or the back and forth movement of the blade 28 made of ferromagnetic material in the magnetic field acting on the contact surface 60, which holds the blade 28 to the contact surface 60, the blade 28 can become magnetized, which can be perceived as disturbing or irritating during subsequent intended use of the blade 28.By moving the blade 28 back and forth on or near the demagnetization surface 84, where an oppositely directed magnetic field acts, following the grinding process, this magnetization of the blade 28 can be reduced or even completely compensated before the blade 28 is put to its intended use.

[0064] The oppositely directed magnetic field acting on the demagnetization surface 84 is preferably generated by at least one magnetic element 56. This magnetic element 56 can be the same one that also generates the magnetic force acting on the contact surface 60 of the holding section 54. The at least one magnetic element 56 is thus preferably designed and / or arranged in or on the holding section 54 such that it generates a magnetic force directed in a first direction on a front side and / or the contact surface 60 of the holding section 54 and simultaneously generates a magnetic force directed in a second direction opposite to the first direction on the rear side and / or the demagnetization surface 84 of the holding section 54.

[0065] Particularly preferably, the at least one magnetic element 56 is designed and / or arranged in or on the holding element 54 such that an amount of the oppositely directed magnetic force acting on the demagnetization surface 84 is smaller than an amount of the magnetic force acting on the contact surface 60 of the holding section 54, with the aid of which the blade 28 to be ground made of ferromagnetic material is held on the holding section 54 during the grinding process.

Claims

[1] Holding element (50) for positioning and holding a blade (28) to be ground in relation to a grinding surface (26) of a grindstone (24) of a grinding machine (10) that is rotatable about a rotation axis (22), wherein the holding element (50) has a fastening section (52) that is designed for fastening to the grinding machine (10), and a holding section (54) that is arranged in the vicinity of the grinding surface (26) of the grindstone (24) when the fastening section (52) is fastened to the grinding machine (10) and on which the blade (28) to be ground is held, so that a cutting edge (32) of the blade (28) to be ground is at a predeterminable angle (α) on the grinding surface (26) of the grindstone (24), and along which the blade (28) to be ground can be moved during a grinding process - always held by the holding section (54) - parallel to a longitudinal extent of the cutting edge (32) of the the blade (28) to be ground can be moved back and forth,so that the cutting edge (32) of the blade (28) to be ground can be moved back and forth over its entire longitudinal extent at the predetermined angle (α) over the grinding surface (26) of the grindstone (24), wherein the holding section (54) of the holding element (50) is designed such that the blade (28) to be ground can come into contact therewith, and that the blade (28) to be ground can be moved back and forth during the grinding process - always in contact with the holding section (54) - parallel to the longitudinal extent of the cutting edge (32) of the blade (28) to be ground, and that at least one magnetic element (56) is assigned to the holding section (54), which is designed to hold a blade (28) to be ground made of ferromagnetic material to the holding section (54) by means of magnetic force during the grinding process, characterized by , that the fastening section (52) comprises a clamping element (66) which is designed for the clamping fastening of the fastening section (52) to a tubular element (38) of the grinding machine (10) which runs at a distance from a grinding surface (26) of the grindstone (24) of the grinding machine (10) and parallel to the axis of rotation (22) of the grindstone (24), wherein the clamping element (66) comprises a receiving hole (68) for receiving the tubular element (38), wherein the tubular element (38) is clamped over its entire surface therein exclusively by means of frictional engagement when the clamping element (66) is clamped to the tubular element (38). [2] Holding element (50) according to claim 1, wherein the at least one magnetic element (56) comprises a permanent magnet and / or an electromagnet. [3] Holding element (50) according to claim 1 or 2, wherein the at least one magnetic element (56) comprises a neodymium magnet. [4] Holding element (50) according to one of the preceding claims, wherein the at least one magnetic element (56) is arranged in the holding section (54). [5] Holding element (50) according to one of the preceding claims, wherein the holding section (54) has a flat contact surface (60) against which the blade (28) to be ground comes to rest and along which the blade (28) to be ground can be moved back and forth during the grinding process - always in contact with the contact surface (60) - parallel to the longitudinal extent of the cutting edge (32) of the blade (28) to be ground. [6] Holding element (50) according to claim 5, wherein the at least one magnetic element (56) is assigned to the contact surface (60). [7] Holding element (50) according to one of the preceding claims, wherein a region of the holding section (54) which comes into contact with the blade (28) to be ground is made of rubber or plastic. [8] Holding element (50) according to one of the preceding claims, wherein the fastening section (52) is designed to fasten the holding element (50) at a predeterminable angle (β) to a part (38) of the grinding machine (10), so that the holding section (54) is aligned at the predeterminable angle (α) and / or a predeterminable distance from the grinding surface (26) of the grindstone (24) of the grinding machine (10). [9] Holding element (50) according to one of the preceding claims, wherein the holding element (50) has an alignment section which is arranged between the fastening section (52) and the holding section (54) and is designed to set the predeterminable angle (α) and / or a predeterminable distance of the holding section (54) to the grinding surface (26) of the grindstone (24) of the grinding machine (10) and to maintain the set angle (α) and / or the set distance during the grinding process. [10] Holding element (50) according to one of the preceding claims, wherein the holding element (50) has a support section (78) which is arranged opposite the holding section (54) at a distance therefrom, so that a receiving gap (80) is formed between the support section (78) and the holding section (54), in which at least a part of the blade (28) to be ground is received during the grinding process. [11] Holding element (50) according to claim 10, wherein the holding section (54) has a flat contact surface (60) against which the blade (28) to be ground comes to rest and along which the blade (28) to be ground can be moved back and forth during the grinding process, and the support section (78) has a support surface (82) which faces the contact surface (60) and extends parallel thereto. [12] Holding element (50) according to claim 11, wherein the support surface (82) has a smaller surface extension than the contact surface (60). [13] Holding element (50) according to one of the preceding claims, wherein a demagnetization surface (84) is formed on a rear side of the holding section (54), on which demagnetization surface a magnetic force opposite to the magnetic force acting on the holding section (54) acts and on which the ground blade (28) can be moved back and forth after the grinding process. [14] Holding element (50) according to claim 13, wherein the oppositely directed magnetic force acting on the demagnetizing surface (84) is generated by the same at least one magnetic element (56) that also generates the magnetic force acting on the holding section (54). [15] Holding element (50) according to claim 13 or 14, wherein an amount of the oppositely directed magnetic force acting on the demagnetizing surface (84) is smaller than an amount of the magnetic force acting on the holding section (54), with the aid of which the blade (28) made of ferromagnetic material to be ground is held on the holding section (54) during the grinding process. [16] Holding element (50) according to claim 6, wherein the at least one magnetic element (56) is arranged set back from the contact surface (60).

Images