A file that creates a profile with a transverse curvature

Abstract

The present invention relates to a file (1) for creating a non-flat contour, in particular with a transverse curvature, on a workpiece (11), comprising a longitudinal axis (3), at least one file element (5, 6) having an abrasive working surface (8) and a depth stop element (7) having a non-abrasive sliding surface (9), said at least one file element (5, 6) and said depth stop element (7) being arranged adjacent to one another in a plane oriented perpendicular to said longitudinal axis (3).

Description

[Technical Field]

[0001] This patent application claims priority from German patent application DE102021215021.7, the contents of which are incorporated herein by reference.

[0002] The present invention ,beside Has directional curvature Ru circle This relates to a file used to create contours in a workpiece. [Background technology]

[0003] In the construction of stringed instruments, particularly plucked instruments with fingerboards, so-called fret bars are attached to the fingerboard at evenly decreasing distances toward the bridge, depending on the scale length, to determine the pitch of the strings pressed down when the instrument is played. The scale length is the length of the unconstrained strings between the nut at the top of the fingerboard and the bridge inlay on the instrument's soundboard. The distance from the nut to the first fret is calculated by dividing the scale length by a divisor / factor of 17.817. This distance is subtracted from the result of dividing the scale length by the same divisor of 17.817. This gives the distance from the first fret to the second fret. Other distances can be calculated correspondingly.

[0004] The fret bars are rod-like and fixed to the fingerboard, i.e., they are sunken into the fingerboard at certain points except for their transversely curved areas, and are decorated so that the fret bars do not protrude differently along the fingerboard. As a result of the decoration, the originally rounded contour of the fret bars is affected. Subsequent restoration of the rounded contour while maintaining the fret bar level created by the decoration process is time-consuming and complicated, but is essential for avoiding unwanted buzzing sounds on the one hand and preserving the center of the fret bar's cross section, which extends perpendicular to the fingerboard, and the pitch defined by them on the other hand. Any undercutting of the fret bar height level created by the decoration process must be avoided. Summary of the Invention [Problem to be solved by the invention]

[0005] The object of the present invention is to simplify the creation of non-flat contours, in particular those with lateral curvatures, on workpieces, in particular fret bar type workpieces, while maintaining the height level already created on the workpiece. [Means for solving the problem]

[0006] This object is achieved by a file having the features of claim 1.

[0007] The essence of the invention is that the file has at least one file element with an abrasive machining surface and a depth stop element with a non-abrasive sliding surface.

[0008] The provision of a non-abrasive sliding surface on the file according to the invention ensures that unwanted material removal in this area is prevented during machining of the workpiece. The non-abrasive area of ​​the file acts as a depth stop.

[0009] This prevents the fret bar height created by the decorating process from being unintentionally reduced when the fret bar is anchored to the fingerboard. However, thanks to at least one abrasive file element, it is possible to machine the remaining contour of the fret bar. This type of fret bar forms a workpiece that can be filed. In particular, the fret bar originally has a rounded outer contour that is weakened, particularly flattened, as a result of decorating. The file according to the invention makes it possible to create non-planar contours, particularly those with rounded and / or transverse curvatures. In particular, the contour of the workpiece that can be produced can be variably determined depending on the contour of the work surface. In a plane perpendicular to the longitudinal axis of the workpiece, the contour is an n-digit spline, in particular a 4-digit spline.

[0010] The workpiece to be machined originally has a polygonal contour, in particular also a triangular cross section.

[0011] The file may further comprise a number of file elements, in particular at least two, in particular exactly two. The file may further comprise a number of depth stop elements. A number of file elements and / or a number of depth stop elements may be combined with one another to form a file with a depth stop function.

[0012] The at least one file element and the at least one depth stop element are in particular detachably connected to one another. This makes it easy to replace the at least one file element and / or the at least one depth stop element. Alternatively, the at least one file element and the at least one depth stop element can be inseparably connected to one another. Inseparably means that the elements can only be separated destructively. If the elements are inseparably connected, the file is constructed in a particularly robust manner.

[0013] The at least one file element is made in particular of a tool material, in particular steel, in particular tool steel. Other tool materials are also possible, in particular aluminum materials. The abrasive surface is in particular provided with a diamond coating and / or a sapphire coating. However, the abrasive surface may also be designed with other types of coating and may additionally or alternatively have a surface structure, in particular with regularly or irregularly arranged ridges and depressions. In particular, the abrasive surface is rough-ground, in particular rough-ground by hand.

[0014] The at least one depth stop element is made of a particularly high-strength material, in particular a high-strength, processable high-performance and / or engineering plastic material, such as polyetheretherketone (PEEK), polyphenylene sulfide (PPS) or polyimide (PI).

[0015] The non-abrasive sliding surface is designed so that it is free of any abrasive coating, and is formed in particular by the substrate of the depth stop element. The substrate of the depth stop element may be a layered material such as TiAlN. The non-abrasive surface is configured to be smooth. The sliding surface may be polished and / or glossy. The sliding surface has a calculated median roughness value Ra of at most 0.4 μm, in particular at most 0.2 μm, in particular at most 0.1 μm, in particular at most 0.05 μm, in particular at most 0.025 μm.

[0016] In particular, the two outer file elements are designed identically and are arranged mirror-symmetrically with respect to one another with respect to a central plane containing the longitudinal axis of the file body. This simplifies the manufacture of the file, since only two different file elements need to be provided to create the file body.

[0017] The processing of the fret bar is simplified due to the fact that at least one file element and depth stop element are arranged adjacent to each other in a plane oriented perpendicular to the longitudinal axis. A file can be placed directly on the fret bar by the at least one file element, and the fret bar can be processed accordingly. The depth stop element prevents unintentional processing of the fret bar in the depth direction, in that the depth stop element rests directly on the fret bar to be processed or on a laterally adjacent fret bar. In particular, the at least one file element and the depth stop element are oriented essentially parallel to each other along the longitudinal axis, and in particular parallel to each other along the longitudinal axis. The at least one file element and the depth stop element are arranged at a distance from each other in a plane oriented perpendicular to the longitudinal axis, in particular at a distance oriented perpendicular to the longitudinal axis.

[0018] The file according to claim 2 ensures a stable structure of the file base. The fabrication and manufacturing of the file are simplified. At least one file element and one depth stop element can be manufactured independently of one another, and in particular the working surfaces can be designed. After this manufacturing, at least one file element is connected to another file element and / or to the depth stop element, in particular firmly connected to one another. The connection is removable, in particular by means of screws or clamps. The connection can also be made inseparable, for example by gluing, soldering or welding. The bonding is carried out by means of a two-component structural adhesive, in particular based on epoxy resins.

[0019] In particular, the connection between the file elements can be improved, especially additionally, by positive locking, for example by sliding the file elements against one another according to the tongue-and-groove principle along the longitudinal axis of the file or at an inclined angle to the longitudinal axis.

[0020] The file according to claim 3 simplifies the production of transverse curvatures in workpieces. In particular, the abrasive surface is substantially concave throughout and has a general curvature, in particular a constant curvature. This allows the file to self-adjust symmetrically during the filing movement, restoring the transverse curvature and especially the roundness. The plumb line through the maximum of the original roundness to the fingerboard and the plumb line through the center of the flattened workpiece to the fingerboard tend to coincide. It is advantageous if the radius of curvature of the abrasive surface is larger than the original radius of curvature of the workpiece.

[0021] In particular, the curvature of the abrasive surface is designed as a section of a circle and has an opening angle relative to the centre point of at least 30°, in particular at least 35°, in particular at least 40°, in particular at least 45°, in particular at least 50°, in particular at least 60°, in particular at most 85°.

[0022] Additionally or alternatively, it is possible to design the concave abrasive cutting surface without a continuous curvature. It has proven advantageous for the concave contour to meet at least one of the following criteria, and in particular all of them: The first criterion relates to the lateral distance between the two axially extending edge regions of the cutting surface. This distance must be greater than the width of the fret bar. The second criterion relates to the symmetry of the concave contour. The contour has the properties of an even real function. This means that the concave contour is configured to be mirror-symmetric with respect to a plane of symmetry that is oriented perpendicular to the width of the fret bar and contains the longitudinal axis of the file. This makes it possible to produce fret bars with improved fret intonation. The central region of the concave contour can be configured relatively pointed. The third criterion relates to the location of the fret bar's local maxima. After complete rounding of the fret bar, its local maxima must be located closer to the axially extending edge regions of the file element than to the surface of the fret bar. This means that the distance in the additive direction from the maximum value of the fret bar to the bottom surface of the file element is less than the distance in the depth direction from the maximum value of the fret bar to the surface of the fingerboard.

[0023] In particular, the work surface is at least partially concave. For example, the profile may also be partially convex, in particular in the shape of a bell curve. The bell curve has several, in particular two, turning points. Advantageously, the concave curve is laterally bounded (defined) by sharp-edged, i.e. parallel edge regions without discontinuous steps.

[0024] Additionally or alternatively, the working surface can also be designed so that a V-shaped recess is substantially provided, the recess being rounded at the bottom. The production of such a recess is simple.

[0025] The file according to claim 4 is robustly designed and can be manufactured in an advantageous, i.e. simplified, manner.

[0026] A file according to claim 5 is advantageous in operation, has a robust design and allows for simple manufacture of the file base.

[0027] Claim 1 A file according to the present invention allows for advantageous repair of individual fret bars, which can be rounded and maintain their level without the need for all, especially adjacent, fret bars to be pre-trimmed. It has been found to be advantageous if the sliding surfaces of the depth stop elements can be arranged outside the fret bar to be machined, especially in the area of ​​the adjacent fret bars. This simplifies the design and construction of the file. The manufacturing effort is reduced. The depth stop elements form a file base with at least one recess into which at least one file element is inserted. In particular, the at least one file element is recessed into the bottom surface of the file base. The at least one file element is designed as a hollow file.

[0028] The file substrate is particularly precisely manufactured, particularly finely ground, particularly ground, particularly polished with a flat, slidable bottom surface that forms a sliding surface. The sliding surface is also called a sliding face. In the plane defined by the local cross-sectional maxima of the individual fret bars, the file substrate extends, in particular, along a length greater than the sum of the two distances between two adjacent fret bars on the fingerboard. In particular, the file substrate is dimensioned so that, at the beginning of processing, it initially rests on at least one or more frets located adjacent to the fret bar being processed. At the beginning of processing, the sliding surface, especially in the case of non-spring file elements, initially rests only on those fret bars that can still be reached by the sliding surface. Due to the fact that the sliding surface rests on at least two adjacent fret bars during processing of the fret bar, particularly towards the end of processing, and moves slidingly in the working direction, unwanted material removal is reliably prevented.

[0029] It is particularly conceivable that two file elements are arranged on the file base. In particular, the file elements may have substantially the same geometric shape but different grit sizes. This type of file simplifies the processing of the workpiece, for example by first pre-processing with a coarser grit file element and then finishing with a finer grit file element. It is also conceivable that the two file elements have the same grit size, so that the file can continue to be used even if one of the two file elements is worn, damaged, and / or destroyed.

[0030] Claim 6 A file according to ensures a secure fixation and fastening of the file element to the file base. The retaining element can hold the file element by positive locking and / or by frictional locking. In particular, the retaining element is designed as a screw, in particular as a clamping screw, in particular in the form of a ball head screw, a through bolt or a translation screw, in particular with a translation thread.

[0031] Claim 7 The file according to claim 1 allows a secure holding of at least one file element. It is advantageous if the at least one file element has several, in particular exactly two, holding grooves. This has advantages, in particular with regard to the fine adjustment of the file element on the file base.

[0032] Claim 8 A file according to prevents unintentional loss of the at least one file element and in particular ensures a secure clamping of the at least one file element by the holding element.

[0033] Claim 9 The file according to allows for axial fixation of the file element by means of a holding element.

[0034] Claim 10A file according to the present invention allows for advantageous workpiece machining. The arrangement of at least one file element relative to the file base, such that the lowest point of the machining surface is recessed in the depth direction relative to the plane defined by the sliding surface, ensures that no material overhang remains on the fret bar to be machined after machining. Therefore, the recessed arrangement is particularly suitable for files in which at least one file element has a relatively large roughness depth, i.e., used for pre-machining or roughing. Therefore, the arrangement of the lowest point in the plane of the sliding surface is advantageous for files with a fine or small roughness depth, which are used in particular for post-machining, in particular for finishing or fine machining. Consequently, the fret bar can be machined along its entire length with the post-machining file, so that its local cross-sectional maximum lies in the plane defined by the sliding surface.

[0035] Claim 1 A file according to the present invention allows for simple automatic compensation of manufacturing tolerances, which may occur in particular with the file elements, especially if the file elements are provided with a diamond coating.

[0036] Claim 1, 11 The file according to the present invention allows for precise positioning of at least one file element relative to the file base through fine adjustment.

[0037] Claim 12 The production of a file element according to is particularly cost-effective. It has been found that the various functions performed by the file element can be separated from one another. The holding function of the file element is particularly performed by the file-holding element. Advantageously, the file-holding element can be held on the file base and attached thereto. In particular, the file-holding element is designed with corresponding design features for being held and / or fixed to the file base. In particular, it has been found that it is not necessary for the file-holding element to be made of a material with an abrasive surface, such as a diamond coating. The file-holding element can be made from a relatively cost-effective material and / or from a material that is relatively easy to machine mechanically.

[0038] In particular, the file insert element is held on and / or within the file-holding element and / or attached thereto. The file insert element has an abrasive surface that is used to process the workpiece. Because the file insert element is held by the file-holding element, special design characteristics of the file insert element are not necessary. The file insert element can be designed with a relatively simple geometric shape and can therefore be produced cost-effectively. Special materials, in particular with a diamond coating, can be used for the file insert element.

[0039] In a further embodiment, the at least one file element (5, 6) forms a file base (2) in which the depth stop element (7) is fixed, in particular inserted into a recess, and in particular the non-abrasive sliding surface (9) is designed to be at least partially convex, in particular to have local extrema (E), in particular maxima, in particular the extrema (E) being in the range of the contour edge positions (C) of the abrasive working surfaces (8) facing each other. F ,D F ) and / or the profile of the non-abrasive sliding surface (9) has a width (B) oriented perpendicular to the longitudinal axis (3), said width being in particular at most 0.2 mm, in particular at most 0.15 mm and in particular between 0.01 mm and 0.1 mm. Reference example The file according to ensures a reliable depth stop function. Due to the fact that the contour of the non-abrasive working surface is at least partially convex, a protrusion is formed on the central file element, which protrudes in particular with respect to the abrasive working surface. The contour of the working surface in the non-abrasive region therefore has an extremum, in particular a maximum.

[0040] In particular, an outer file element is arranged on the file base, the two curvatures of which have a common center of curvature, i.e. in particular form a common curvature that is only interrupted by a depth stop element.

[0041] A file having a depth distance oriented perpendicular to the imaginary connecting line defined by the contour edge positions of the facing abrasive surfaces ensures that unintentional material removal is more reliably prevented. The depth distance is in particular at least 0.02 mm, in particular at least 0.04 mm, in particular at least 0.05 mm. In particular, the depth distance relative to the width oriented perpendicular to the longitudinal axis, in particular perpendicular to the midplane of the file body, is between half and five times the width.

[0042] Files with a maximum width of 0.3 mm, in which the contour of the non-abrasive sliding surface is oriented perpendicular to the longitudinal axis, ensure that unwanted material removal is avoided when the file is tilted relative to the workpiece. Widths of 0.01 mm to 0.1 mm are especially preferred.

[0043] Both the features of the claims and the following description of embodiments of the file according to the invention are suitable, on their own or in combination with one another, for further embodying the subject matter according to the invention. The respective combination of features does not represent any restrictions with regard to the further development of the subject matter of the invention, but is essentially merely exemplary.

[0044] Additional features, advantageous embodiments and details of the invention are set forth in the following description of exemplary embodiments in conjunction with the drawings. [Brief explanation of the drawings]

[0045] [Figure 1] 1 shows a cross section through a file according to the invention in a plane perpendicular to the longitudinal axis of the file body. FIG. [Figure 2] FIG. 2 is an enlarged detailed view of Detail II in FIG. 1. [Figure 3] FIG. 10 shows a plan view of a file according to a second exemplary embodiment in which the file base forms a depth stop element. [Figure 4] FIG. 4 is a cross-sectional view taken along line IV-IV in FIG. 3. [Figure 5] FIG. 5 shows a side view of the file in FIGS. 3 and 4. [Figure 6] FIG. 4 shows a side view of the file element of the file in FIG. 3. [Figure 7] FIG. 7 is a cross-sectional view taken along line VII-VII in FIG. 6. [Figure 8] FIG. 10 shows a bottom view of a file according to the third exemplary embodiment. [Figure 9] 9 is a cross-sectional view taken along line IX-IX in FIG. 8. FIG. [Figure 10] FIG. 10 shows a side view of a file according to a fourth exemplary embodiment having a through bolt. [Figure 11] 11 shows a side view of the file element of the file of FIG. 10 with the screw and file element disassembled. FIG. [Figure 12] FIG. 10 shows an enlarged cross-sectional view of a file according to a fourth exemplary embodiment with a screw having a translation thread. [Figure 13]7A and 7B show views of other file elements corresponding to FIG. 6 according to a further embodiment. [Figure 14] FIG. 14 shows a side view of the file element according to FIG. 13. [Figure 15] 14 is a cross-sectional view taken along line XV-XV in FIG. 13. FIG. [Figure 16] 14A and 14B show views of the file element corresponding to FIG. 13 according to a further embodiment. [Figure 17] FIG. 17 is a cross-sectional view taken along line XVII-XVII in FIG. [Figure 18] FIG. 10 shows a perspective view of a file according to a further example embodiment. [Figure 19] FIG. 19 is a diagram showing a cross-sectional representation taken along line XIX-XIX in FIG. 18. [Figure 20] A figure showing a plan view of the file holding element container of the file in Figure 18. [Figure 21] FIG. 21 is a cross-sectional view taken along line XXI-XXI in FIG. 20. [Figure 22] FIG. 19 is a plan view of the file holding element guide of the file in FIG. 18. [Figure 23] 19 shows an enlarged cross-sectional representation of the retaining element of the file in FIG. 18. FIG. [Figure 24] 10A and 10B show a plan view of a file-holding element of a file according to a further exemplary embodiment; [Figure 25] FIG. 25 is a cross-sectional view taken along line XXV-XXV in FIG. 24. [Figure 26] FIG. 25 shows a cross-sectional representation of the file insert element of the file in FIG. 24. [Figure 27] 10A-10C show plan views of file bases of files having variable lengths according to further exemplary embodiments. [Figure 28] FIG. 28 is a cross-sectional view taken along the line XXVIII-XXVIII in FIG. 27. [Figure 29] FIG. 28 shows a cross-sectional representation corresponding to FIG. 27 with a surface-adjustable file substrate. [Figure 30]28 shows a cross-sectional representation of a file base corresponding to FIG. 27 according to a further exemplary embodiment having a variably adjustable compression spring preload. [Figure 31] FIG. 10 shows a plan view of a file with several file elements according to a further exemplary embodiment. [Figure 32] FIG. 32 is a diagram showing a cross-sectional representation taken along the cutting line XXXII-XXXII in FIG. 31. [Figure 33] FIG. 33 is a cross-sectional view taken along the line XXXIII-XXXIII in FIG. 31. DETAILED DESCRIPTION OF THE INVENTION

[0046] The file shown in Figures 1 and 2, generally designated 1, comprises a file base 2 and a file handle attached to the file base 2. The file handle is located outside the plane of the drawing and is not shown in Figure 1. The file 1 can also be designed without a file handle. The file 1 is gripped directly by the file base 2, which allows for more precise work.

[0047] The file body 2 has a longitudinal axis 3 oriented perpendicular to the plane shown in FIG.

[0048] The file base 2 is formed by two file elements 5, 6 arranged next to each other in the view shown in FIG. 1. The file elements 5, 6 are made in particular of a tool material, in particular of a steel material, in particular of a tool steel, or alternatively of an aluminum material. The file elements 5, 6 are firmly connected to each other, for example glued together. In particular, the respective contact surfaces between the two file elements 5 and 6 function as bonding surfaces. The bonding can take place over a large area, in particular over the entire surface. Such an adhesive connection is stable and allows in particular a high positional accuracy of the file elements relative to each other. In particular, the two file elements are firmly connected to each other in pairs.

[0049] The file base 2 has a slot-shaped recess between the two file elements 5, 6. According to the illustrated exemplary embodiment, the slot-shaped recess extends over the entire drawing area. It is conceivable that the file elements 5, 6 have a common contact surface that is outside the drawing area. The file elements 5, 6 can be glued together at these contact surfaces. Alternatively, it is conceivable that the file base 2 with the slot-shaped recess is manufactured in one piece, i.e., consists of only a single file element with an integrated slot-shaped recess.

[0050] The file body 2 is configured to be mirror-symmetrical with respect to the central plane 4. The file body 2 has a profile-like design, with the longitudinal axis 3 coinciding with the profile longitudinal axis. The file elements 5, 6 are designed in particular identically and are arranged mirror-symmetrical with respect to one another with respect to the central plane 4.

[0051] The two outer file elements 5, 6 have an abrasive surface 8 that is used to machine the workpiece. In the illustrated exemplary embodiment, the abrasive surface 8 is formed by a diamond coating.

[0052] A depth stop element 7 is arranged in the file base 2, in particular in a slot-shaped recess. The depth stop element 7 is arranged in particular between the file elements 5, 6 and in particular coaxially with respect to the central plane 4.

[0053] The depth stop element 7 has a non-abrasive sliding surface 9 which is designed in particular without a coating, and which is formed in particular by the base material of the depth stop element 7, in particular by a steel material, in particular by a tool steel, and which is polished and / or polished.

[0054] The abrasive surfaces 8 are each designed to be particularly continuously concave and have a radius of curvature R F Each of the abrasive surfaces 8 has a radius of curvature R F and have a circle segment contour with position A F ~C F and D F ~B F The center position of the curved contour M F Each opening angle α Fis approximately 45° in the illustrated exemplary embodiment. F is located in the central plane 4.

[0055] The contour of the non-abrasive sliding surface 9 is shown in particular in the detailed view according to Figure 2. The contour of the non-abrasive sliding surface 9 is at least partially convex, in particular completely convex. The non-abrasive sliding surface 9 is configured curved and at position C F and D F The imaginary connecting line 10 has a torsion-free transition to the abrasive surface 8 at the end position C F and D F . With respect to the connecting line 10, the non-abrasive sliding surface 9 has an extremum E, in particular an extremum with a depth distance t with respect to the connecting line 10. The depth distance t is oriented perpendicular to the connecting line 10. If the extremum E and the extremum of the spline spanned by the file elements 5, 6 coincide, small gaps may occur parallel to the longitudinal axis 3 of the file 1. These gaps also provide a torsion-free transition between the abrasive working surface 8 and the non-abrasive sliding surface 9 within the meaning of the present application.

[0056] The extremum E is located in the central plane 4. In particular, the contour of the non-abrasive sliding surface 9 is configured to be mirror-symmetrical with respect to the central plane 4. The extremum E protrudes from the machining surface, in particular from the abrasive machining surface 8. The extremum E serves as a depth stop for the file 1, i.e. as the line of contact of the file 1 with the workpiece.

[0057] The depth stop element 7 and therefore the non-abrasive sliding surface 9 has a width B oriented perpendicular to the longitudinal axis 3, in particular perpendicular to the central plane 4, which is in particular a maximum of 0.3 mm, in particular 0.01 mm to 0.1 mm.

[0058] In Figure 1, workpiece 11 is shown below file 1 and is arranged as a fret bar in the fingerboard area of ​​a stringed instrument, in particular a plucked instrument 12. The fingerboard area of ​​plucked instrument 12 includes fingerboard 13. Fret bar 11 is arranged at a center point M W With respect to curvature R W It has a curved contour with a center point M W is placed on the central plane 4. The curvature R of the fret bar 11W is the curvature R of the abrasive grain processed surface 8 F When the fret bar 11 is anchored to the fingerboard 13, the original curved profile of the fret bar 11 is flattened. The flattened profile of the fret bar 11 has a radius of curvature R W Contour position A with W ~C W C with a flat curve along W From D W up to, and again with curvature R W D W From end position B W This occurs up to.

[0059] Contour edge position A, oriented perpendicular to the central plane 4 W and B W The width of the fret bar 11 between the contour end position A F and B F It corresponds to the width of the file base 2 between the two.

[0060] position C W and D W By flattening the fret bar 11 between the workpieces, the initial workpiece height W0 has been reduced to the flattened workpiece height W1. The flattened workpiece contour can be rounded using a file 1 by grinding away the flanks 14 of the fret bar 11 with the file 1. The flanks 14 are the material areas of the fret bar 11 that protrude from the work surface 8 and the sliding surface 9. In FIG. 1, the flanks 14 are defined by the intersection points S1 and S2 and the contour end location C, respectively. W and D W The flank 14 is formed by a contour starting from section C. The flank 14 is removed continuously along the entire length of the fret bar 11, W ,D W The width of the remaining fret bar C is reduced to width B. In this region, the file 1 abuts the fret bar 11 at extremum E, thereby preventing unwanted material removal. By tilting the file 1 around the contact edge 15 at extremum E, i.e., by rotating the file 1 clockwise or counterclockwise at the contact edge 15 as shown in Figs. 1 and 2, the remaining remaining fret bar C is removed. W ,D W may be rounded at the end.

[0061] Further exemplary embodiments are described below with reference to Figures 3 to 7. Structurally identical parts are provided with the same reference numerals as in the first exemplary embodiment and reference is hereby made to that description. Structurally different but functionally identical parts are provided with the same reference numerals with the suffix a.

[0062] A notable difference compared to the first exemplary embodiment is that the file body 2a of the file 1a is formed by a depth stop element 7a. The file body 2a is essentially rectangular in shape and has a length L, a width B, and a height H. According to the illustrated exemplary embodiment, the width B is smaller than the length L. Advantageously, the width B is determined depending on the length of the fret bar to be machined. It is possible to select the width B between 10% and 300%, in particular between 30% and 200%, in particular between 50% and 100% of the length of the fret bar. The height H extends in particular along a depth direction 16, which is oriented perpendicular to the width B and perpendicular to the length L of the file body 2a.

[0063] The file elements 5a, 6a are arranged on the file base 2a so that the longitudinal axes 3 of the file elements 5a, 6a, respectively, extend along the width B of the file base 2a. The file elements 5a, 6a are arranged next to each other along the length L of the file base 2a. In particular, the file elements 5a, 6a have a file element length along their longitudinal axes 3 that is the same as the width B of the file base 2a.

[0064] The file base 2a has an upper side 17 and a bottom side 18 that define the height H of the file base 2a. The upper side 17 is located at the top in FIG. 4. The bottom side 18 is located at the bottom in FIG. 4. The file base 2a is point-symmetrical with respect to its center of gravity G. According to FIG. 4, by rotating the file base 2a 180° around its center of gravity, the upper side 17 and the bottom side 18 are interchanged. The file base 2a has a plurality of recesses 19, each of which extends along the depth direction 16 from the upper side 17 or the bottom side 18. The recesses 19 are not continuous (connected) in the depth direction 16 and extend over approximately 50% of the height H of the file base 2a. The recesses 19 are continuous along the width B.

[0065] The top side 17 and bottom side 18 are designed substantially identically and include two outer non-abrasive sliding surfaces 9 and an abrasive working surface 8 arranged between them in the longitudinal direction L. When working a fret bar with each file element 5a, 6a, the file 1a can be placed on an adjacent fret bar that has not been worked by the sliding surfaces 9. The sliding surfaces 9 prevent material from being removed from the adjacent fret bar. The file base 2a has the function of a depth stop element 7a.

[0066] A spring receptacle (spring seat) 20 adjoins the recess 19 in the depth direction 16. Along the width direction, several spring receptacles 20, in particular two, in particular at least three spring receptacles 20, can be arranged below the recess 19. The spring receptacles 20 are each designed as a cylindrical blind hole. In particular, the spring receptacles 20 are not continuous in the depth direction 16.

[0067] A spring element 21 is inserted into each spring container 20 and is axially supported at the bottom of the spring container in the depth direction 16. According to the illustrated exemplary embodiment, the spring elements 21 are designed as mechanical springs, in particular as compression coil springs. The mechanical springs can also be designed as leaf springs. Other designs of the spring elements are also possible, such as pneumatic springs.

[0068] The compression spring 21 is dimensioned so that in the unloaded state it pops out of the spring container 20 and projects into the recess 19 .

[0069] The file elements 5a, 6a are inserted into the recesses 19. Each file element 5a, 6a is arranged on the file base 2a with an abrasive surface 8, which is designed in particular in the form of a hollow file with a concave contour, so that the concave contour protrudes from the upper side 17 or the bottom side 18, respectively. The concave contours each have a minimum value M. It is particularly advantageous if the minimum value M is set back (retracted) in the depth direction 16 with respect to the upper side 17 or the bottom side 18.

[0070] Each file element 5a, 6a is supported by a compression spring 21 on its bottom surface opposite the concave contour.

[0071] The file elements 5a, 6a have a plurality of lateral retaining grooves 22 arranged at a distance from one another along the width direction. The retaining grooves 22 are used to retain and / or adjust the file elements 5a, 6a on the file base 2a. The retaining grooves 22 are also referred to as adjustment grooves. According to the illustrated exemplary embodiment, one adjustment groove 22 is designed with a V-shaped groove profile, while the other adjustment groove 22 is designed with a rectangular groove profile. The adjustment grooves 22 extend along an inclined groove direction 23 inclined at an inclination angle α with respect to the depth direction 16. The adjustment grooves 22 extend in the depth direction 16 with a variable groove depth T N and maximum groove depth T N,max is formed on the surface facing the abrasive processing surface 8.

[0072] For holding and finely adjusting the respective file element 5a, 6a in the associated recess 19, in particular along the depth direction and in particular against the spring force of the compression spring 21, a number of, in particular two, retaining elements 24 are provided for each file element 5a or 6a. The retaining elements are designed as fine adjustment screws 24, in particular with a screw thread, in particular with a fine thread. The fine adjustment screws have the function of adjusting, in particular finely adjusting, the file elements 5a, 6a, in particular against the spring force exerted by the spring elements 21. The fine adjustment screws 24 have the function of positioning, in particular finely positioning, in particular the minimum value M of the concave contour of the respective file element 5a, 6a in the depth direction 16. According to the illustrated exemplary embodiment, the fine adjustment screws 24 are designed as ball-head screws of the Grub screw type. In two opposite end faces extending along the height H and width B, transverse bores with internal threads are arranged, each of which opens into a recess 19. Grub screws are screwed into the transverse bores until they engage with their ball heads in the respective adjustment grooves 22. At least one adjustment groove 22 is V-shaped, so that the respective file elements 5a, 6a are positioned axially in the width direction and / or along the depth direction 16 and are therefore fixed. Other adjustment grooves 22 are rectangular or U-shaped, so that the file elements 5a, 6a have a certain amount of play in the longitudinal direction of the longitudinal axis 3, thereby allowing for tolerances and tolerances, so that the respective file elements 5a, 6a may unintentionally tilt within a small angular range, in particular less than 2°, in particular less than 1°, in particular less than 0.5°, during movement along the depth direction 16. Such tilting can be compensated for by the aforementioned tolerances in the axial direction, so that unwanted jamming of the file elements 5a, 6a in particular into the file base 2a is prevented.

[0073] To operate the fine adjustment screws 24, the screws have internal polygonal socket openings at their rear ends. It is also contemplated that the fine adjustment screws 24 are not designed as grub screws.

[0074] To fix the fine adjustment screws 24, additional locking grub screws 25 can be used, which can be screwed through the respective fine adjustment screws 24, in particular extending in the width direction and in particular transversely to the screwing direction of the respective fine adjustment screws 24. For this purpose, each fine adjustment screw 24 has a through-hole with an internal thread that corresponds to the external thread of the locking grub screws 25.

[0075] The fine adjustment screws 24 allow immediate and direct fine adjustment of the position of the file elements 5a, 6a relative to the file base 2a along the depth direction 16. This fine adjustment is necessary especially during the manufacture of the file elements 5a, 6a, in particular due to manufacturing tolerances.

[0076] The concave contour of the work surface 8 is in particular arcuate and has in particular a constant radius of curvature R F The fact that the arc length is smaller than the length of the semicircle ensures that the file elements 5a, 6a do not rest on the finger plate and thus may prevent complete machining of the workpiece. The arc length is in particular 180°, in particular at most 175°, in particular at most 170°, in particular at most 165°, in particular at most 145°. In particular, each file element 5a, 6a has a radius of curvature R towards its side edge. F The end faces are rounded in the width direction.

[0077] According to a further exemplary embodiment, not shown, which substantially corresponds to the previous exemplary embodiment according to Figures 3 to 7, at least one file element 5a, 6a has a flat working surface 8. The working surface 8 is therefore not particularly concave or convex. The working surface 8 is not curved.

[0078] At least one file element is arranged on the file base so that the working surface is flush with the surface of the file base, meaning that the abrasive working surface is in the plane defined by the sliding surface of the file base.

[0079] This file can be used specifically to prepare a single fret bar if it is to be inserted into the fingerboard between other fret bars, these other fret bars already being rounded. With the files described herein, pre-cutting is possible with flat file elements, and is particularly performed with a file according to the first exemplary embodiment in FIGS.

[0080] The third exemplary embodiment will now be described with reference to Figures 8 and 9. Structurally identical parts are given the same reference numerals as in the two first exemplary embodiments, and their descriptions are hereby referred to. Structurally different but functionally identical parts are given the same reference numerals with the suffix b.

[0081] A notable difference compared to the previous exemplary embodiment is that the position of the file element 5b is adjusted by means of fine adjustment screws 26. In particular, two fine adjustment screws 26 are arranged spaced apart from each other along the width B and are used for fine adjustment of the file element 5b in the depth direction 16. Thus, tilting of the file element 5b with its longitudinal axis 3 relative to the plane defined by the bottom surface 18 is eliminated. The fine adjustment screws 26 comprise a sleeve-like receptacle 27 with an external thread that can be screwed into a corresponding internal thread of a threaded receptacle 28 in the file base 2b. The fine adjustment screws are therefore securely positioned in the file base 2b and fixed thereto.

[0082] A radially projecting fret stop 29 protruding from the upper side 17 of the file base 2b is provided as an integral part of the sleeve receptacle 27. The fret stop 29 has an outer diameter larger than the inner diameter of the screw receptacle 28. The sleeve receptacle 27 has a through-hole with a fine internal thread into which the pin 30 of the fine adjustment screw 26 can be screwed with a corresponding fine external thread. The pin 30 has a ball head and can be screwed into the bottom wall of the file element 5b in the depth direction 16 up to the stop. The fine adjustment screw 26 allows for immediate and direct fine adjustment of the position of the file element 5b relative to the file base 2b along the depth direction 16. This fine adjustment may be necessary, especially due to manufacturing tolerances, especially during the manufacture of the file element 5b.

[0083] A fourth exemplary embodiment will now be described with reference to Figures 10 and 11. Structurally identical parts are given the same reference numerals as in the previous exemplary embodiment, the description of which is hereby referred to. Structurally different but functionally identical parts are given the same reference numerals with the suffix c.

[0084] A notable difference compared to the previous exemplary embodiment is that the file elements 5c are fixed directly to the file base 2c of the file 1c. Retaining elements 24c designed as through bolts are used for this purpose. The retaining elements 24c can be designed as screws with a metric thread and an internal hexagonal head, so-called Allen screws. A corresponding fastening screw 31 designed as a blind hole with an internal thread is arranged in the file base 2c for each retaining element 24c. In particular, the fastening screws 31 are arranged in the file base 2c, spaced apart from one another in the width direction 2.

[0085] A further difference compared to the previous exemplary embodiment is that the retaining grooves 22c are formed in the side wall facing away from the retaining element 24c, in particular arranged opposite thereto. A plurality of protrusions 32 corresponding to the retaining grooves 22c are formed, in particular integrally, in the file base 2c. The retaining grooves 22c and the corresponding protrusions 32 are each inclined at an inclination angle α with respect to the depth direction 16. The file element 5c can move along the groove direction 23 relative to the file base 2c.

[0086] In the illustrated exemplary embodiment, the file element 5c may also be designed without the retaining groove 22c and the corresponding protrusion 32. The frictional connection created by the retaining element 24c between the file element 5c and the file base 2c prevents axial movement of the file element 5c along the longitudinal axis 3.

[0087] To simplify this flexible positioning of the file element 5c on the file base 2c, the through-hole 33 in the file element 5c is designed, in particular in the width direction 16, with a gap width b that is greater than the outer diameter of the retaining element 24c. It is particularly conceivable for the through-hole 33 to be configured as being circular. According to the illustrated exemplary embodiment, the through-hole 33 is substantially elongated in the depth direction 16 by a longitudinal extension. The gap width a in the width direction B is particularly smaller than the gap width b in the depth direction 16. This allows the file element 5c to be variably fixed in the width direction by the retaining element 24c. The assembly of the file element 5c on the file base 2c is simplified. In particular, the elongated through-hole 33 makes it possible to compensate for manufacturing tolerances during the manufacturing of the file element 5c and / or the file base 2c. In particular, the retaining element 24c is arranged without play in the through-hole 33 in the width direction.

[0088] Here, precise adjustment of the file element is achieved by means of steel foils, not shown in detail, positioned and clamped at a number of appropriate positions between the surface of the file element 5c facing the working surface 8 and the corresponding surface of the file base 2c.

[0089] Another exemplary embodiment is described below in connection with Figure 12. Structurally identical parts are given the same reference numerals as in the previous exemplary embodiment, and reference is hereby made to that description. Structurally different but functionally identical parts are given the same reference numerals with the suffix d.

[0090] A notable difference compared to the previous exemplary embodiment is that the file element 5d is held directly in the depth direction 16 by the holding element 24d. The holding element 24d is arranged as a clamping screw in a recess 34 provided for this purpose in the upper side 17 and extends along a through-hole in the depth direction 16 as far as the recess 19 in which the file element 5d is arranged. On its bottom side facing the concave working surface 8, the file element 5d has a receiving hole with an internal thread that corresponds to the external thread of the holding element 24d.

[0091] As with the previous exemplary embodiment, precise adjustment of the file element is achieved using steel foil.

[0092] A plurality of holding elements 24d can be provided along the width direction, which particularly simplifies the design of the file 1d and in particular the attachment of the file elements 5d to the file base 2d.

[0093] Further exemplary embodiments are described below with reference to Figures 13 to 15. Structurally identical parts are given the same reference numerals as in the previous exemplary embodiments, and reference is hereby made to their descriptions. Structurally different but functionally identical parts are given the same reference numerals with the suffix e.

[0094] A notable difference compared to the previous exemplary embodiment is that the file element 6e is made in multiple pieces. The file element 6e includes a file-retaining element 35 and a file insert element 36 that is retained by the file-retaining element 35.

[0095] The file-holding element 35 is designed as a substantially open rectangular hollow strip, i.e. in particular substantially U-shaped. The file-insertion element 36 is inserted into the file-holding element 35 and is held in the depth direction 16 by at least one holding element 37. According to the illustrated exemplary embodiment, there are a plurality of, in particular two, holding elements 37. The holding elements 37 are designed in particular as permanent magnets, in particular arranged at the bottom of the recess of the file-holding element 35, in particular integrated into the file-holding element 35. In particular, the file-insertion element 36 is made of a ferromagnetic material and is held in the file-holding element 35 by the magnetic holding element 37.

[0096] It is advantageous if the file insert element 36 has a geometrically simple design. The manufacture of the file insert element 36 is simplified.

[0097] A retaining groove 22 provided for connection with the file base 2 is designed into the file retaining element 35 .

[0098] To ensure axial fixation along the longitudinal axis 3 of the file insert element 36 on the file-holding element 35, a locking pin 38 oriented in the depth direction 16 is arranged and connects the file insert element 36 to the file-holding element 35. The locking pin 38 also has the function of absorbing shear forces that may occur, in particular along the longitudinal axis 3, during machining of the workpiece.

[0099] It is advantageous if the notches 39 are arranged in the edge region of the file element 6e and in particular in the region of the separation plane between the file retaining element 35 and the file insert element 36. The notches 39, which in particular have a wedge-shaped design, serve as tool openings, in particular for applying a lever tool, to separate the file insert element 36 from the file retaining element 35 against the magnetic retaining force.

[0100] Another exemplary embodiment is described below with reference to Figures 16 and 17. Structurally identical parts are given the same reference numerals as in the previous exemplary embodiment, and reference is hereby made to that description. Structurally different but functionally identical parts are given the same reference numerals with the suffix f.

[0101] This exemplary embodiment basically corresponds to the previous exemplary embodiment, in that the file element 6f is designed with a file retaining element 35 and a file insert element 36. A number of cross threads extending along the depth direction 16 serve as retaining elements 37f to ensure the connection between the file insert element 36 and the file retaining element 35. In particular, the file insert element 36 has a through hole, and the file retaining element 35 has a locking female thread that corresponds to the external thread of the retaining screw 37f.

[0102] In particular, the threads 37f are arranged on the file insert element 36 outside the curved workpiece machining area. In particular, the retaining screws 37f are designed as countersunk screws and are recessed with respect to the outer surface 18. This ensures that the workpiece machining is not negatively impaired due to the threaded connection.

[0103] Further exemplary embodiments are described below with reference to Figures 18 to 23. Structurally identical parts are given the same reference numerals as in the previous exemplary embodiments, and reference is hereby made to their descriptions. Structurally different but functionally identical parts are given the same reference numerals with the suffix g.

[0104] In file 1g, file element 6g has a multi-piece design with file insert element 36g held in, and in particular screwed to, file holding element 35g.

[0105] The file insert element 36g is made in one piece and has a protruding strip-like working web 40. The working web 40 includes an abrasive working surface 8. The working web 40 is designed with a concave surface.

[0106] The file insert element 36g has a plurality of through holes, four in the illustrated exemplary embodiment, through which a plurality of retention screws can be threaded to secure the file insert element 36g to the file retention element 35g.

[0107] The file-holding element 35g is designed in multiple pieces and comprises a file-holding element container 41 and a file-holding element guide 42. The file-holding element guide 42 is designed in the shape of a web and has a rectangular, in particular square, cross-sectional area in a plane perpendicular to the web longitudinal axis 43.

[0108] In a direction perpendicular to the web longitudinal axis 43, the file-holding element guide 42 has two guide holes 44, into each of which a slide bushing 45 can be inserted. In particular, the guide holes 44 are continuous, i.e. they extend over the entire height of the file-holding element guide 42. A dowel pin 46 is inserted into each of the slide bushings 45 and is held in a recess in the file base 2g. The dowel pins 46 are oriented along the depth direction 16 in the file 1g. The file-holding element guide 42 is movable on the dowel pins 46, i.e. along the depth direction 16, in particular relative to the file base 2g.

[0109] A plurality of compression springs 21 are disposed on the bottom surface of the file-retaining element receptacle (receptacle) 41. The compression springs 21 are preloaded and disposed between the file base 2g and the file-retaining element 35g, thereby applying an actuation force to the file-retaining element 35g, which pushes it out of the recess 19 and away from the file base 2g.

[0110] The file-retaining element guide 42 has a transverse through-hole 47 into which a transverse plain bearing bush 48 with a transverse pin 49 is inserted. The transverse through-hole 47 is oriented perpendicular to the web longitudinal axis 43 and perpendicular to the guide hole 44. The file-retaining element guide 42 is held in the file-retaining element container 41 by the transverse pin 49 provided in the transverse plain bearing bush 48. The file-retaining element container 41 is rotatable on the file-retaining element guide 42 about the transverse pin 49, i.e., it is articulated. For this purpose, the file-retaining element container 41 has a slot-shaped cutout 50. In a plane perpendicular to the guide hole 44, the file-retaining element guide 42 has an outer surface shape that corresponds to the slot-shaped cutout 50. The file-retaining element container 41 has four threaded holes on its upper side facing the file insert element 36g, which correspond to the fixing openings on the file insert element 36g. To accommodate the transverse pins 49, the file-holding element receptacle 41 has aligned transverse holes 51 arranged opposite the cutouts 50. A threaded hole 75 is arranged perpendicular to each of the transverse holes 51. To secure the transverse pins 49 in the respective transverse holes 51, grub screws (not shown) can be screwed into the threaded holes 75. For this purpose, the transverse pins 49, which have a cylindrical basic shape, can be at least partially flattened.

[0111] Two retaining grooves 22g are provided in one side wall of the file-retaining element receptacle 41. The retaining grooves 22g are configured to be cylindrical. The retaining grooves 22g may also have a non-circular inner contour, which may in particular be configured to be rectangular in a plane perpendicular to the groove longitudinal axis 52. The retaining grooves 22g are designed as blind holes. The hole longitudinal axis 52 is inclined at an inclination angle n to the transverse axis of the transverse hole 51. The inclination angle n is in particular less than 10°, in particular between 2° and 8°, in particular between 4° and 7°, in particular between 5° and 6°. In particular, the inclination angle n is 5.7°.

[0112] A retaining element 24g engages each of the retaining grooves 22g. The retaining elements 24g are shown enlarged. The retaining elements 24g are attached to the threaded section A. G , cylindrical section A Z and conical section A KThread section A is an adjusting screw having a G The external thread of corresponds to a corresponding internal thread in a through hole in the file base 2g. To fix the axial position of the holding element 24g in the file base 2g, a locking grub screw 25 can be arranged in the transverse hole and directed towards it.

[0113] Cylinder Section A Z is thread section A G The core diameter is smaller than the thread diameter of the cylindrical section A. Z Starting from the core diameter of the cone section A K has an outer cone angle k which in particular corresponds to the inclination angle of the retaining groove 22g, in particular being identical to the inclination angle n. By means of the retaining element 24g designed as a fine adjustment screw, it is possible to adjust the file element 6g on the file base 2g along the depth direction 16 with an accuracy of 1 / 1000 mm to 5 / 10000 mm.

[0114] The use of the slide bush 45 and the slide pin 46 improves the adjustment of the file element 6g, in particular because the sliding surface between the slide pin 46 and the slide bush 45 is better protected from dust and chips. Its movement is possible more precisely, in particular with a higher resolution. The horizontal load on the holding element 24g and the corresponding hole in the file base 2g, in particular in the working direction, is reduced, in particular to the point of being negligible.

[0115] Manufacturing and / or assembly tolerances of the individual components can be precisely compensated for in the plane of movement of the file-holding element 35g. It has been found that tolerances in the range of 1 / 100 mm to 3 / 100 mm occur during the production of the working web 40 due to wire erosion or fine milling with abrasive material and / or due to thick, uneven coatings. When replacing the file insert element 36g, a change in the zero position of adjustment may be necessary, particularly for the production of working webs 40 aligned perpendicular to the depth direction 16 and for the deepest position of the working web 40 in the depth direction 16. Due to wear-related changes in the thickness of the layer of abrasive material on the working web 40, readjustment may also be necessary. In the illustrated exemplary embodiment, readjustment is possible using the controlled file-holding element guide 42 in the depth direction 16 and, in particular, due to the axially mounted tiltable file-insert element receptacle and fine adjustment.

[0116] Retaining element 24g is conical section A K , the retaining groove 22g does not have a point contact, but rather a line contact. Therefore, the pressure between the retaining element 24g and the retaining groove 22g is reduced. This results in more uniform loading and wear between the adjusting screw as the retaining element 24g and the adjustment opening as the retaining groove 22g.

[0117] Further exemplary embodiments are described below with reference to Figures 24 to 26. Structurally identical parts have the same reference numerals as the previous exemplary embodiments, to which description reference is hereby made. Structurally different but functionally identical parts are given the same reference numerals with the suffix h.

[0118] A change compared to the previous exemplary embodiment is that the file-holding element 35h is designed in one piece.

[0119] The file insert element 36h can be inserted into a notch 39 provided for this purpose in the file holding element 35h. Two threaded holes 66 are formed laterally adjacent to the notch 39, into each of which a retaining screw 37h can be screwed and which can engage a shoulder 53 provided for this purpose on the file insert element 36h. The file insert element 36h is fastened to the file holding element 35h by a retaining screw (not shown). The attachment and, in particular, removal of the file insert element 36h from the file holding element 35h is simple. The file insert element 36h can be replaced quickly and time-efficiently.

[0120] A further difference is that the file-holding element 35h only has a single holding groove 22h, which is arranged in the center of the file base 2h or of the file-holding element 35h, in particular in the machining direction. Thus, the articulated installation of the file-holding element 35h according to the previous exemplary embodiment can be omitted.

[0121] Another embodiment is described below with reference to Figures 27 and 28. Structurally identical parts are given the same reference numerals as in the previous exemplary embodiment, and reference is hereby made to that description. Structurally different but functionally identical parts are given the same reference numerals with the suffix i.

[0122] In the file, the file base 2i is designed in two pieces, with a first file base part and a second file base part, in which the recess 19 is formed, being arranged so as to form a closed file base 2i. A parting plane extends across the processing direction 54 at an inclination angle s, which is in particular between 1° and 45°, in particular between 2° and 30°, in particular between 5° and 15°. The parting surfaces of the first and second file base parts facing the parting plane coincide with each other. In particular, the parting surfaces are each designed to be flat, allowing for easy positioning of the file base parts relative to each other.

[0123] Two transverse holes 55 are arranged on one end face of the file base 2i for a length-adjustable design of the file base 2i. For this purpose, each transverse hole 55 has an inner thread section 57 along the longitudinal axis 56 of the hole, an adjacent mating section 58, and an outer cutout section 59 that opens toward the end face. A correspondingly manufactured fitting screw can be screwed into the thread of the thread section 57, enabling a secure and precise connection of the file-holding element parts with one another, particularly so that their parting surfaces contact one another. To form file bases 2i of different lengths, it is conceivable to give various second file base parts different length dimensions from the first file base parts. This allows for variable adjustment of file bases with different length dimensions.

[0124] Further exemplary embodiments are described below with reference to Figure 29. Structurally identical parts are given the same reference numerals as in the previous exemplary embodiment, and reference is hereby made to that description. Structurally different but functionally identical parts are given the same reference numerals with the suffix j.

[0125] Compared to the previous exemplary embodiment, the file base 2j allows targeted adjustment of the deformation of the non-abrasive sliding surface 9, in particular in the area laterally adjacent to the recess 19j into which the file-holding element with the file insert element can be inserted. This makes it possible to design the file base 2j in surface areas with a convex or concave curve.

[0126] This is achieved in particular in that the file base 2j is designed door-like in a plane oriented perpendicular to the machining direction 54, with two opposing web walls 60 and a top wall 61 connecting the web walls 60. The sliding surface 9 is arranged on the top wall 61. In order to reduce, and in particular to avoid, stress peaks in the file base 2j, a relief notch can be arranged on the bottom surface of the top wall 61 opposite the sliding surface 9, in particular in the transition region to the web wall 60.

[0127] In the lower base region, at a distance from the ceiling wall 61, the web walls 60 are mechanically connected to one another by a tension / compression element 62, in particular in the form of a threaded rod. The tension / compression element 62 is fixed in an internal threaded hole in one of the web walls 60 and is further held in place by an additional translation element 63 in the form of a nut. The threaded hole is designed as a blind hole.

[0128] In the opposing web wall 60, which has a through hole, a tension / compression element is guided through the through hole and fixed by two clamping elements 63 located on opposite sides of the through hole. The tension / compression element 62 can be used to apply tension or compression to the web wall 60. The tension / compression element 62 enables the mechanical interlocking of the web wall 60. When tension is applied, a convex curved surface is formed on the non-abrasive sliding surface 9. When compression is applied to the web wall 60, a concave curved surface is formed on the non-abrasive sliding surface 9.

[0129] Another embodiment is described below with reference to Figure 30. Structurally identical parts have the same reference numerals as the previous exemplary embodiment, and reference is hereby made to that description. Structurally different but functionally identical parts are given the same reference numerals with the suffix k.

[0130] The file base 2k has a preload element 64 that can be screwed as a translation screw into an opening provided for this purpose on the bottom surface of the file base 2k. The preload element 64 interacts with an adjustment element 65 in the form of a perforated disk that is arranged on the bottom surface of the compression spring 21, i.e., opposite the file holding element 35. Depending on the screw-in depth of the preload element 64, the adjustment element 65 is displaced, thus reducing the depth of the cutout for the compression spring 21, i.e. increasing the preload on the compression spring 21. By means of the preload element 64 and the adjustment element 65, it is possible, in particular, to variably adjust the preload that can be applied to the compression spring 21.

[0131] Another embodiment is described below with reference to Figures 31 to 33. Structurally identical parts have the same reference numerals as the previous exemplary embodiment, and reference is hereby made to that description. Structurally different but functionally identical parts are given the same reference numerals with the suffix l.

[0132] The file base 21 has at least one guide groove 67, in particular a plurality of guide grooves 67, in particular three parallel-oriented guide grooves 67, which serve to accommodate a plurality of file elements 6l. Along the longitudinal direction of the guide groove 67, there may be a plurality of fret bar distance markings and / or internal dowel pins arranged in corresponding holes or guide bushes in the file base 2l, which simplify the positioning of the file elements 6l at a defined distance in the longitudinal direction. In particular, this allows the file elements 6l to be arranged adjacent to one another in the longitudinal direction, so that different fret bars can be simultaneously machined with the file 1l. For visualization reasons, the file elements 6l are shown in Figures 31 and 32 arranged at the same distance from one another along the longitudinal groove 67. If the file elements 6l are arranged according to the scale length, the distance between two adjacent file elements 6l will correspondingly differ. To simplify the positioning of the file elements 6l, multiple markings may be provided on each of the file elements 6l. It is understood that several markings may be made on the file base 2l, particularly for different graduation lengths.

[0133] Each file element 6l has a file-holding element 35l and a file-insertion element 36l.

[0134] The file 1L allows for the simultaneous machining of multiple fret bars on one instrument. In particular, the file elements 6L can be variably fixed to the file base 2L relative to one another. Each file element 6L is fastened to the file base 2L by the file holder element 35L via an abutment 74. Each file element 6L has a plurality of fastening webs 70 on its file holder element 35L that protrude into the guide groove 67, and two fastening screws 68 engage with each of the fastening webs 70. At least one spring element 71 is arranged on the bottom surface of the file holder element 35L opposite the fastening webs 70. In particular, there are two spring elements 71, each designed as an elastic pressure piece, in particular in the form of a pressure spring screw, with a spring-loaded pressure ball that engages in a corresponding recess in the file insert element 36L. The spring elements 71 can be pressed or screwed into the respective recesses. The spring movement of the file insert element 36l is maintained. The file retaining element 35l is prevented from sliding off by a combined positive and frictional locking.

[0135] Alternatively, the spring element 71 can be designed as a leaf spring which supports the file insert element 36l on the file retaining element 35l. The leaf spring is fastened, in particular screwed, riveted and / or welded, to the bottom surface opposite the fastening web 70 and can have an undulating contour in a plane perpendicular to the longitudinal direction of the guide groove 67. The contour protrudes in at least one place into a corresponding recess in the file insert element 36l, whereby a corresponding positive lock is achieved for the spring element.

[0136] The spring element 71 applies a clamping force to the file insert element 36l that holds the file insert element 36l positively and frictionally locked to the file retaining element 35l.

[0137] It is advantageous if the file base 2l has sufficient flexibility, especially parallel to the long sides of the fingerboard, i.e. perpendicular to the machining direction, which in particular makes it possible to adapt the file base 2l to irregular instrument necks.

[0138] The file insert elements 36l are designed in particular similarly to the file elements of the first exemplary embodiment. In particular, the depth stop function of these file elements 6l is independent of the height of the adjacent fret bars, but only, i.e., directly, depends on the height of the fret bar to be machined. Fine adjustment of the file elements 6l on the file base 2l is not necessary for the file 1l. In particular, differences in the height of the non-abrasive crests can be compensated for by springing the file insert elements 36l with spring elements 71. Height differences can arise due to manufacturing tolerances and / or due to different stock removal rates of different fret bars during their simultaneous machining.

[0139] The dovetail-equipped file insert element 36l is guided in the file holder element 35l in particular by a corresponding dovetail guide 72 along the machining direction 54.

[0140] Unacceptable movement of the file insert element 36l along the machining direction 54 can also be prevented by mechanical stop elements (not shown) arranged in front of and behind the file base 2l and / or on the file holding element 35l along the machining direction 54 of the file base 2l. In particular, fixed stop elements are provided. In particular, removable stop elements are fixed to the file base 2l and / or to the file holding element 35l. Additionally or alternatively, a plurality of recesses may be provided in the file insert element 36l, by means of which the spring elements 71 can engage.

[0141] The stop elements are designed in particular as countersunk screws, the heads of which are flattened on one side to approximately 1 / 3 of the head diameter, preventing the file insert element 36l from being pulled out or pushed out, in particular by the rounded part of the countersunk head. In order not to hinder the spring movement of the file insert element 36l, the bottom surface of the screw head may respectively have a distance of approximately 0.1 mm to 0.2 mm from the file insert element 36l in this position. [Explanation of symbols]

[0142] 1;1a;1b;1c;1d 2a;2b;2c;2d Screw base 3 Longitudinal Axis 5,6;5a;6a;5b;5c;5d Screw element 7;7a;7b;7c;7d Depth stop elements 8 Abrasive Surface 9 Non-abrasive sliding surface 11 Workpiece 16 Depth direction 19;19d recess 21 Compression spring 22;22c adjustment groove 24;24c;24d holding element 35 Screw holding element 36 File insert element

Claims

1. A file (1a; 1b; 1c; 1d) of essentially rectangular parallelepiped shape having a length (L), a width (B) and a height (H) measured in a depth direction (16) that creates a profile with a transverse curvature on the fret bar (11), a. A longitudinal axis (3) extending along said width (B) of the file (1a; 1b; 1c; 1d); b) depth stop elements (7a; 7b; 7c; 7d) having flat, non-abrasive sliding surfaces (9) that do not work the fret bar (11) on the planes (17, 18) of the files (1a; 1b; 1c; 1d) that are oriented perpendicular to the depth direction (16) and face the fret bar (11); and c) at least one file element (5a; 6a; 5b; 5c; 5d) having an abrasive processing surface (8) that projects at least partially in the depth direction (16) from the plane (17, 18) defined by the non-abrasive sliding surface (9) of the depth stop element (7a; 7b; 7c; 7d) and processes the fret bar (11), the at least one file element (5a; 6a; 5b; 5c; 5d) and the depth stop elements (7a; 7b; 7c; 7d) are arranged adjacent to one another vertically or horizontally in a plane oriented perpendicular to the longitudinal axis (3) and extending in the depth direction (16); and a file (1a; 1b; 1c; 1d) in which the depth stop elements (7a; 7b; 7c; 7d) form a file base (2a; 2b; 2c; 2d) in which at least one recess (19; 19d) for inserting the at least one file element (5a; 6a; 5b; 5c; 5d) is arranged, the recess (19; 19d) extending along the depth direction (16) of the file (1a; 1b; 1c; 1d), d. said at least one file element (5a; 6a) is mechanically preloaded in said depth direction (16) on said file base (2a) by means of a compression spring (21); and / or e. A file (1a; 1b; 1c; 1d), characterized in that said at least one file element (5a; 6a; 5b) is arranged on said file base (2a; 2b) so as to be adjustable in said depth direction (16) by means of a translation screw.

2. 2. A file (1a; 1b; 1c; 1d) according to claim 1, characterized in that the at least one file element (5a; 6a; 5b; 5c; 5d) and the depth stop elements (7a; 7b; 7c; 7d) are connected to one another, in particular in pairs.

3. The abrasive surface (8) is designed to be concave, in particular to have a radius of curvature (R) of the original radius of curvature of the fret bar (11). Ｗ ) greater than the radius of curvature (R Ｆ 2. A file (1a; 1b; 1c; 1d) according to claim 1, characterized in that it has a curvature having a curvature of 1 / 2.

4. 2. A file (1a; 1b; 1c; 1d) according to claim 1, characterized in that said at least one file element (5a; 6a; 5b; 5c; 5d) is contoured along said longitudinal axis (3).

5. 2. A file (1a; 1b; 1c; 1d) according to claim 1, characterized in that the contour of the abrasive surface (8) and / or the non-abrasive sliding surface (9) is constant along the longitudinal axis (3).

6. 2. A file (1a; 1b; 1c; 1d) according to claim 1, characterized in that it comprises a holding element (24; 24c; 24d) for holding said at least one file element (5, 6; 5a; 6a; 5b; 5c; 5d), in particular in said at least one recess (19; 19d).

7. 7. A file (1a; 1b; 1c; 1d) according to claim 6, characterized in that the at least one file element (5, 6; 5a; 6a; 5b; 5c; 5d) has an adjustment groove (22; 22c), in particular for retaining the engagement of the retaining element (24; 24c; 24d), the adjustment groove (22; 22c) extending in particular along the depth direction (16) of the file (1a; 1b; 1c; 1d).

8. The adjusting grooves (22; 22c) have a variable groove depth (T Ｎ 8. A file (1a; 1b; 1c; 1d) according to claim 7, characterized in that it has a

9. 9. A file (1a; 1b; 1c; 1d) according to claim 7 or 8, characterized in that the adjustment groove (22; 22c) has a V-shaped groove profile in a plane perpendicular to the depth direction (16).

10. 2. A file (1a; 1b; 1c; 1d) according to claim 1, characterized in that the at least one file element (5a; 6a; 5b; 5c; 5d) is arranged on the file base (2a; 2b; 2c; 2d) so that the lowest point (M) of the abrasive surface (8) is located within the plane (17, 18) defined by the non-abrasive sliding surface (9) or is set back from the plane (17, 18) by a vertical distance in the depth direction (16), said vertical distance being in particular less than 1.0 mm, in particular less than 0.7 mm, in particular less than 0.5 mm, in particular less than 0.3 mm, in particular less than 0.1 mm, and in particular greater than or equal to 0.001 mm.

11. 2. A file (1a; 1b; 1c; 1d) according to claim 1, characterized in that the at least one file element (5a; 6a; 5b) is arranged on the file base (2a; 2b) so as to be adjustable in the depth direction (16) by means of a translational fine screw.

12. 2. A file (1a; 1b; 1c; 1d) according to claim 1, characterized in that the at least one file element (6e; 6f) is of multi-piece design and in particular comprises a file-holding element (35) and a file-insertion element (36) held by the file-holding element (35).

Images