TOOL HEAD AND METHOD FOR POSITIONING A CUTTING PLATE IN THE TOOL HOLD OF THE TOOL HEAD

Description

[0001] The invention relates to a tool head according to the preamble of claim 1 and a method for positioning a cutting insert according to the preamble of claim 10. Such a tool head and such a method for positioning a cutting insert (15) are known from document CH 679755 A5. State of the art

[0002] German patent DE-OS 36 36 618 discloses a cutterhead for woodworking machines, particularly planers. It has a one-piece shaft body with several parallel grooves that narrow towards the outer surface. Each groove houses a profiled disposable cutter, clamped by a centrifugal wedge, which engages positively in a corresponding profile on the side surface of a retaining strip located between the disposable cutter and the centrifugal wedge. The retaining strip is rigidly connected to the shaft body and elastically deformable. It is positioned at such a distance from the side wall of the groove that, when the centrifugal wedge is released, an intervening cutter can be easily pulled out longitudinally and a new cutter can be inserted with virtually no play.When the centrifugal wedge generates clamping force through rotation, the retaining bar is pressed firmly against the disposable knife by slight elastic deformation, thus locking it securely in place. However, the knife can only be clamped in a single, fixed position.

[0003] German utility model DE-U-89 14 809 discloses a cutter head for machining wood, plastics, and the like, in particular for longitudinal profiling of strips and panels, with a cylindrical base body having several axially parallel grooves open to the outer surface. A cutter is clamped in each groove between a side wall of the groove and a retaining strip, with a toothed section on the back of the cutter engaging positively with a corresponding toothed section on the side wall. The groove narrows towards the outer surface of the base body in a wedge shape. A centrifugal wedge is arranged in this wedge, which clamps the cutter firmly between the retaining strip and the other side wall when the base body is rotating.

[0004] US Patent Application No. 2002 / 0046632 discloses a tool body with one or more tool holders in which cutting edges can be inserted and held by a clamping mechanism. To keep tooling costs low, US 2002 / 0046632 proposes resharpening the cutting edges by removing an equal amount of material from the cutting edge base, thus creating a new reference edge. The inserted cutting edges have a groove at a distance from the cutting edge base into which a protruding rib formed in the tool holder engages when the cutting edge is clamped in the holder. The groove is provided on the flat side of the cutting edge opposite the cutting edge and prevents the cutting edge from slipping radially during operation. According to US 2002 / 0046632, the rib can alternatively be provided on the clamping wedge to achieve the same purpose.

[0005] US Patent Application No. 2005 / 0265795 discloses a tool head with a tool holder in which a cutting edge can be clamped by means of a clamping wedge. The cutting edge has a chamfer at the base of the cutting edge and opposite the flat side with the cutting edge, which provides the necessary clearance when the cutting edge is inserted into the tool holder opening.

[0006] To replace or adjust the blade, the centrifugal wedge is first released by applying radial inward force, for example, with a hammer blow. The retaining strip, which is slightly elastically deformed towards the blade when under tension, returns to its relaxed position. In this position, precisely defined by the stop edge between the two strips, the blade is loosened sufficiently to allow it to be easily pulled out along the axis of the base body. Subsequently, after sharpening if necessary, the blade can be reinserted axially, for example, in a position offset outwards by one tooth width. As soon as the cutter head is set into rapid rotation, the centrifugal wedge tightens due to centrifugal force. The blade is now securely and precisely clamped. Because the centrifugal wedge is self-locking, it remains in the tensioned position even after the cutter head is stopped.One advantage of the described cutter head is that the screws do not need to be loosened when changing the cutter. A disadvantage, however, is that the cutter can only be pulled out of the groove axially. This means that adjacent cutter heads must first be removed from the tool spindle before the cutter can be removed.

[0007] With conventional cutterheads that don't have centrifugal wedges, using wide blades typically requires several screws to secure them to the cutterhead. This increases the effort required when changing blades. Another problem with these conventional cutterheads is that the pressure plates are screwed into a groove in the cutterhead, opposing the centrifugal force generated during rotation. At high speeds, the centrifugal forces can cause a slight shift in the blade, which affects the accuracy of woodworking and leads to larger tolerances. Object of the invention

[0008] Therefore, one objective of the present invention is to provide a tool head, in particular a cutter head, for a woodworking machine tool, and a method in which the tool, or cutting insert, can be inserted and removed in the radial direction. A further objective is to provide a tool head in which, when changing a tool or cutting insert, prior disassembly of adjacent tool heads is no longer necessary. Another objective is to propose a tool head in which the effort required for changing tools is minimized. A further objective is that, when changing a tool, the new cutting insert is precisely aligned in the radial and preferably axial direction. Description

[0009] According to the invention, the aforementioned objectives are achieved by the features of claims 1 and 10. Advantageous further developments are defined in the dependent claims.

[0010] The present invention relates to a tool head for a woodworking machine, comprising a cylindrical, conical, or profiled base body, which has at least two tool holders, preferably evenly distributed around its circumference, for receiving a cutting insert. A single tool holder is formed by a radially open groove in which a cutting insert can be clamped between a first groove wall and a locking element serving as a pressure jaw. A centrifugal wedge, which can be inserted into the groove, can press the locking element against the cutting insert and fix the latter in the tool holder. A first positive locking connection is provided between the cutting insert and the first groove wall, which fixes the cutting insert in the radial direction.

[0011] According to the invention, this tool head is further characterized in that a pressure element is provided in the tool holder, which presses a cutting insert placed in the tool holder radially against a stop. The tool head designed in this way has the significant advantage that the tool is automatically positioned radially during clamping, as it is automatically moved radially outwards by the pressure element and brought into contact with a projection on the tool. This ensures precise positioning of the cutting inserts in the tool holder without any additional effort.

[0012] The pressure element can be a spring or an elastically deformable plastic or metal part, which preferably fits into a recess in the cutting plate or engages at the base of the cutting edge.

[0013] According to the invention, the pressure element is positioned in the groove such that it acts radially on the cutting insert when the tool is clamped. The pressure element is elastically or spring-elastically deformable and is made, for example, of an elastically deformable plastic or a spring element, such as a coil spring. The pressure element is preferably located where the lower base surface of the cutting insert rests on a shoulder of the tool holder, so that the pressure element can interact with the lower base surface of the cutting insert. The pressure or spring element can be inserted into the groove of the tool holder or arranged on the locking element.

[0014] One advantageous embodiment provides that the pressure element is provided or arranged on the locking element. Viewed longitudinally, it can be positioned below the magnets, i.e., closer to the base of the locking element. The pressure element can be designed as a plastic positioning stud projecting from the surface. The positioning stud can, for example, be inserted into a hole in the locking element.

[0015] According to another embodiment, the pressure element is a spring that is used simultaneously for the lateral and radial positioning of the cutting edge and for pressing the locking element against the centrifugal wedge jaws.

[0016] Advantageously, a second positive locking connection is provided between the locking element and the centrifugal wedge. This arrangement of positive locking connections—namely, between the cutting insert and the tool head on the one hand, and the locking element and the centrifugal wedge on the other—has the advantage that relative movement between the locking element and the cutting insert is possible during clamping, because there is no positive locking connection between the cutting insert and the locking element. Furthermore, the proposed arrangement of the positive locking connections allows the cutting insert to be inserted radially into the groove.

[0017] Advantageously, the centrifugal wedge has a bore with an internal thread into which a clamping screw with an external thread can be inserted. The centrifugal wedge can be moved into the clamping position by turning the clamping screw in a first direction and into the tool-changing position by turning the clamping screw in a second, opposite direction. Compared to the prior art, this tool holder has the advantage that the centrifugal wedge is pre-tensioned radially outwards as soon as the tool is clamped. This prevents the centrifugal wedge and the cutting insert from shifting when the tool head begins to rotate. According to an advantageous embodiment, the clamping screw is a threaded stud with an engagement element, e.g., an internal hexagon socket or a Torx screw drive profile, on one end face and a preferably cylindrical screw head on the other.When the centrifugal wedge is inserted into the tool holder, the cylindrical screw head rests against the bottom of the groove, which serves as a counter bearing. It is conceivable that the screw head has a detent projection on its end face, which can engage with play in a corresponding blind hole in the bottom of the groove. This has the advantage that the centrifugal wedge cannot shift within the groove. Furthermore, the blind hole and detent projection are designed to allow for radial pre-assembly of the clamping screw.

[0018] Advantageously, a screw hole with an internal thread is provided in the base of the groove, and the shank of the clamping screw has two threaded sections with opposing screw threads. This has the advantage that, with appropriate selection of the screw thread direction, the centrifugal wedge moves away from the base of the groove when the clamping screw is screwed into the screw hole. According to another embodiment, the clamping screw can be rotatably but axially immovably inserted into the bore of the centrifugal wedge. In this way, too, the centrifugal wedge can be pressed against the locking element by turning the clamping screw.

[0019] The locking element is conveniently mounted in the tool holder without screws, or, in the tool-changing position, is positively locked in place by the centrifugal wedge using magnets. This has the advantage of allowing for quick insertion or removal, thus simplifying tool changes.

[0020] According to a preferred embodiment, either the locking element or the centrifugal wedge is equipped with at least one magnet. Providing at least one magnet has the advantage that the cutting plate, which is advantageously made of a weakly magnetizable material, is held against the locking element. This has the advantage that the cutting plate is drawn against the locking element in the tool-changing position. Because the cutting plate is also tilted when the centrifugal wedge is released, it can be easily grasped with the fingers.

[0021] Preferably, the at least one magnet is inserted flush with the surface of the locking element into a recess. This has the advantage that the cutting plate can lie flat against the locking element. For reasons of symmetry, at least two recesses spaced apart from each other are expediently provided in the locking element, into which magnets are inserted flush.

[0022] Advantageous features include one or more recesses in the lower area of ​​the locking element, located a short distance from the base of the locking element, particularly in the lower third of the locking element. However, other positions are equally possible depending on the dimensions of the cutting plate.

[0023] Advantageously, the centrifugal wedge has a front wedge surface oriented towards the first groove wall and a rear surface opposite the wedge surface, oriented towards the second groove wall and forming an acute angle with the front wedge surface. Preferably, the wedge surface has an axially extending, groove-shaped recess. The recess has the advantage that the contact pressure is concentrated on the areas of the centrifugal wedge adjacent to the recess.

[0024] Advantageously, the wedge surface is provided with a raised section extending in the axial direction. This raised section, e.g., an elongated bead, can ensure a positive fit with the locking element.

[0025] Advantageously, a first pressure surface is provided above the depression and a second pressure surface with a minimum width of at least 1 mm, preferably at least 2 mm, and particularly preferably at least 3 mm is provided below the depression.

[0026] Preferably, the first groove wall of the groove takes an angle between 0 and 40 degrees with a radial extending from the center of the tool head, preferably between 15 and 35 degrees and particularly preferably between 20 and 30 degrees.

[0027] Advantageously, the base of the centrifugal wedge is formed with a step extending preferably parallel to the longitudinal axis of the bore, such that a first base surface adjacent to the front wedge surface and a second base surface adjacent to the back surface are present. The second base surface forms an angle greater than 90 degrees with the back surface, preferably between 90.1 and 95 degrees and particularly preferably between 90.5 and 94 degrees. This physical design of the centrifugal wedge has the advantage that a tilting movement of the centrifugal wedge can be caused when the tool holder is released.

[0028] A centering pin (e.g. press fit) can be embedded in the first groove wall for the lateral centering of the cutting insert and, if applicable, the locking element.

[0029] According to a particularly advantageous embodiment, a third positive locking connection is provided between the centrifugal wedge and the locking element for the lateral centering of the locking element. This is a particularly advantageous design which, in conjunction with the second positive locking connection, enables the radial and axial adjustment of the cutting plate.

[0030] The cutting insert for the tool head of a woodworking machine has a cutting edge on one side (the blade face) and a positioning groove on the opposite side. This cutting insert is characterized by a functional surface in the form of a chamfer or a rounded edge on the diagonally opposite side, the depth of which is preferably at least 15% of the insert thickness. This cutting insert has the advantage of being directly and positively fixed in the tool body. Advantageously, the chamfer is ≥ 0.6 mm. This significantly larger chamfer, compared to known cutting inserts, allows an elastically deformable pressure element to expand through the increased clearance between the groove wall and the cutting insert when the centrifugal wedge is clamped.The enlarged chamfer is therefore important for the correct radial positioning of the cutting insert. In addition, this functional surface also has safety implications, as without it the brittle cutting inserts could break during clamping and fly off during operation.

[0031] Preferably, only a single positioning groove is provided, the lower edge of which is located at a distance of < 10 mm and preferably < 8 mm from the base surface of the cutting insert.

[0032] It is also important that the positioning groove is located within a clamping area. This clamping area is limited in depth by the step of the first groove wall and in height by the apex of the top surface of the centrifugal wedge, as well as the first pressure surface of the centrifugal wedge.

[0033] Advantageously, the cutting plate has at least one U-shaped recess for lateral positioning. However, the cutting plate can also have no U-shaped recess. In that case, lateral positioning can be achieved, for example, by two lateral positioning elements between which the cutting plate is positioned.

[0034] Advantageously, the centrifugal wedge is moved into the clamping and changeover positions using a clamping screw. The advantages associated with the aforementioned method variants were already discussed above in the discussion of the tool head according to the invention.

[0035] Advantageously, the cutting insert is clamped in the direction of centrifugal force by means of a clamping screw that engages the centrifugal wedge. This has the advantage that the centrifugal forces acting during operation of the rotating tool head no longer cause any displacement of the centrifugal wedge. The result is higher precision in the machining of the workpieces.

[0036] The invention also relates to a method for positioning a cutting insert in a tool holder of a tool head, in which a cutting insert placed in the tool holder is pressed against a stop by means of a pressure element provided in the tool holder and appropriately aligned, by the pressure element exerting a radially outward force on the cutting insert. It is important that the positioning occurs automatically when the tool is clamped. The pressure element can be responsible for radial, lateral, or both lateral and radial positioning.

[0037] Preferably, before reaching its final clamping position, the cutting insert is pressed radially outwards against a stop in a form-fitting manner. This has the advantage that the cutting insert is precisely positioned in the tool holder and cannot slip during operation.

[0038] Advantageously, the cutting plate is positioned before reaching its final position using an elastic element or brought into a form-fitting stop against a stop strip.

[0039] Advantageously, the cutting plate is releasably drawn to the locking element in the changeover position. This is conveniently achieved with the aid of a magnet, which can be arranged on the locking element or the centrifugal wedge.

[0040] According to a particularly advantageous variant of the method, the centrifugal wedge is loosened using the clamping screw. In contrast to the prior art, this allows the centrifugal wedge to be loosened without a hammer.

[0041] Advantageously, the locking element is held in a form-fitting manner by the centrifugal wedge in the tool change position.

[0042] The cutting plate is advantageously clamped against the stop and in the direction of flight.

[0043] Advantageously, the cutting plate is pressed against the locking element by the pressure element in the change position.

[0044] Exemplary embodiments of the invention are now described with reference to the following Figures 1 to 17 and 19 to 21 It is described in more detail. It shows: Figure 1: A partial side view of a first embodiment of a single tool holder of a tool head with a cutting insert clamped by means of a locking element and a centrifugal wedge (working position); Figure 2: A view as in Fig. 1, wherein the cutting insert is in the changeover position; Figure 3: A side view of the entire tool head, wherein the cutting insert is in the changeover position; Figure 4: An end and a side view of the centrifugal wedge; Figure 5: A front and a side view of the locking element; Figure 6: A front and a side view of a cutting insert designed as a (profile) knife; Figure 7: A screw with two threaded sections for tightening and loosening the centrifugal wedge; Figure 8: A further embodiment of a centrifugal wedge according to the invention; Figure 9: A further embodiment of a locking element according to the invention with a transverse groove at a distance from the base of the knife and a positioning aid; Figure 10: Two further embodiments of a cutting insert in the form of a profile knife in front and side views, wherein the cutting inserts differ in the elongated recesses;Figure 11: A partial view of a second embodiment of a single tool holder of a tool head with a centrifugal wedge according to ; Figure 8 and an elastic pressure element for positioning the cutting insert in the tool change position; Figure 12: The tool head of Figure 11 with the cutting insert in the (clamped) working position; Figure 13: A partial view of a third embodiment of a single tool holder of a tool head with a modified pressure element and a short locking element; and Figure 14: The tool head of Figure 13 with the cutting insert in the (clamped) working position; Figure 15: A partial view of a fourth embodiment of a single tool holder of a reamer tool head with a short cutting insert; Figure 16: The tool head of Figure 15with the cutting insert in the tool change position; Figure 17: Another embodiment of a tool head in the form of a flattening cutter head; Figure 18: An additional embodiment of a tool head in which the clamping screw is a clamping pin that is supported with a head at the base of the groove; Figure 19: An embodiment of a pressure element that ensures the radial positioning of the cutting insert when the tool is clamped. Figure 20: The pressure element of Fig. 19 , when it is inserted into the tool holder and the cutting insert is clamped by the centrifugal wedge, in an enlarged detail view; Figure 21: The pressure element of Fig. 19 , when the cutting insert is inserted into the tool holder and the centrifugal wedge is released, also in an enlarged detail view.

[0045] In the Figures 1 to 7A tool head 11 according to the invention for the rotary machining of wood and its components is shown. It has several tool holders 13 arranged around its circumference, each of which can hold a tool in the form of a cutting insert 15. A radially narrowing groove 19 is provided in the tool holder 13, which can run parallel to the axis or at an angle to the axis of rotation 17 of the tool head 11. The cutting insert 15, which in the example shown is provided by a profile knife 21 ( Fig. 6The tool head 11 is formed by a centrifugal wedge 23 and a locking element 25. The locking element 25 rests against the cutting insert 15 and is pressed against the flat side of the cutting insert 15 by the centrifugal wedge 23. The latter is thus clamped in the working or clamping position between a first groove wall 27 of the tool head 11 and the locking element 25. The tool head according to the invention is characterized in that the cutting insert can be inserted into and removed from the tool holder 13 in a radial direction. Furthermore, the locking element 25 is held in the tool holder 13 without screws. Another special feature is that the centrifugal wedge 23 is tightened or loosened for all widths within the application range according to the invention (typically between 7 mm and 150 mm, preferably between 15 and 100 mm) by a single screw 29.that no hammer is required to release the tool holder, as is usually the case with conventional tool heads. The aforementioned special features of the tool head according to the invention are explained in more detail below.

[0046] As mentioned above, the groove 19 is tapered radially outwards in a wedge shape, i.e., the first groove wall 27 and a second groove wall 31 opposite the first groove wall 27 are inclined relative to each other. The centrifugal wedge 23 is received in the groove 19. The dimensions of the centrifugal wedge 23 and the groove 19 are preferably such that the centrifugal wedge can be inserted radially into the groove 19 in the absence of the locking element 25. However, it is also conceivable that the dimensions of the centrifugal wedge 23 and the groove 19 are such that only lateral insertion is possible. Both embodiments are equally possible within the scope of the present invention.

[0047] The centrifugal wedge 23 has a front wedge surface 33 that rests against the locking element 25, and a rear surface 35 that rests flat against the second groove wall 31. If no locking element is provided, the front wedge surface 33 rests directly against the cutting plate. The front wedge surface 33 is interrupted by a recess 37 extending longitudinally along the centrifugal wedge 23, so that a first pressure surface 39 is located above the recess 37 and a second pressure surface 41 is located below the recess. The second pressure surface 41 has a projection 43 in the form of a longitudinally extending bead, which enables a positive locking connection with a corresponding, complementary recess 47 of the locking element 25.

[0048] The base of the centrifugal wedge 23 is stepped, with a first base surface 49 adjacent to the front wedge surface 33 and a second base surface 51 adjacent to the rear surface 35. The first and second base surfaces 49 and 51 are separated by a step 53, which preferably extends substantially parallel to the rear surface 35. The second base surface 51 forms an angle of 90 degrees or more, preferably between 91 and 93 degrees, with the rear surface 35. This allows the centrifugal wedge 23 to tilt in the changeover position, as will be explained in more detail below.

[0049] For weight reduction, one or more spaced-apart elongated holes 55 can be provided in the centrifugal wedge 23. Between the elongated holes 55 is a screw hole 57 with a longitudinal axis 59 extending from the top surface 61 to the second bottom surface 51. The longitudinal axis 59 of the screw hole 57 extends substantially parallel to the back surface 35. The screw hole 57 has an internal thread 63 for receiving a rear threaded section 99 of the screw 29 ( Fig. 7 ).

[0050] Analogous to the base surface 49, 51 of the centrifugal wedge 23, the groove base is also stepped. It comprises a first groove base surface 65, which corresponds to the second base surface 51 of the centrifugal wedge 23, and a second groove base surface 67, which corresponds to the first base surface 49. A screw hole 69 with an internal thread 70 is provided in the first groove base surface 65. The screw hole 69 is collinear with the longitudinal axis 59, so that by turning the screw 29, the centrifugal wedge 23 can be moved from an upper clamping position, in which the locking element 25 and the cutting insert 15 are pressed firmly against the first groove wall 27 according to the invention, to a lower tool-changing position, in which the cutting insert 15 can be removed radially.

[0051] While – as mentioned above – the base surface 51 forms an angle of ≥ 90 degrees with the back surface 35, the angle between the first groove base surface 65 and the back surface 31 is preferably approximately 90 degrees. If the base surface 51 forms an angle of > 90 degrees with the back surface 35, then when the tool holder is opened, the second base surface 51 of the centrifugal wedge 23 near the step 53 comes into contact with the first groove base surface 65 first. This causes a transverse force to act on the centrifugal wedge 23 when it reaches the tool change position, which, due to the existing tolerances of the screw threads, causes the centrifugal wedge 23 to tilt. Fig. 2 ). In this process, the locking element 25 and the cutting plate 15 are released from the first groove wall 27.

[0052] A special feature of the locking element 25 is that at least one, but preferably two or more magnets 69 are provided in the lower area ( Fig. 5These are preferably received flush with the adjacent surface of the tool in recesses 71. The magnets 69 serve to hold the cutting inserts 15, which are usually made of a weakly magnetizable material, in contact with the locking element 25, particularly during tool changes, so that the tool can be removed more easily.

[0053] Just above the recess 47, two elastically deformable plastic studs 73, in particular those made of an elastomeric material, are provided at a distance from each other in the locking element 25. These can be inserted into corresponding holes 75 in the locking element 25. The purpose of the studs 73 is to push the cutting plate 15 upwards when clamped. The function of the studs 73 is described in more detail below.

[0054] For the lateral centering of the locking element 25 in the groove 19, a U-shaped recess 77 is provided in the center of the rear mounting section. In the clamping position, an axially adjustable centering pin 79 engages in this recess 77, which is received in a pin hole 81 of the tool head body ( Figs. 1 to 3 The pin hole 81 is machined into the tool head body at an angle to the first groove wall 27.

[0055] Just above the pin hole 81, only a single groove 83 is provided in the first groove wall 27. A stop bar 85 is positively engaged in this groove 83. The groove 83 and the corresponding stop bar 85 can have a square, polygonal, or round cross-section. In the clamping position, the stop bar 85 interacts with a groove 87 in the cutting plate 15 for precise positioning ( Fig. 6This groove 87 is wider than the stop strip 85 by a certain distance, preferably by at least 5% and particularly preferably by at least 10%. Advantageously, the groove 87 is between 20% and 80% wider than the stop strip. In specific embodiments, the groove 87 is between 30% and 60% wider than the stop strip 85. It is conceivable that, instead of the stop strip 85, a corresponding elongated stop 85a is formed directly in the groove wall 27.

[0056] The cutting plate 15, which according to Fig. 6Designed as a profile knife 21, it can have a U-shaped recess 89 centrally at the base of the tool, analogous to the locking element 25, which serves to center the cutting insert 15. When the cutting insert 15 is inserted into the groove 19, the head of the centering bolt 79 engages in the U-shaped recesses 77, 89 of the locking element 25 and the cutting insert 15, so that they lie exactly on top of each other. The cutting insert has a cutting edge 92 on its face 90. A functional surface in the form of a chamfer 94 is formed on the edge diagonally opposite the cutting edge 92.

[0057] How the Figs. 1 to 3The first groove wall 27, which can be removed, is not a flat surface but has a shoulder 91 at a distance from the groove base, against which the cutting insert can rest. The rear (recessed) wall section above the shoulder 91 is designated by reference numeral 93 and the front (proximate) wall section by reference numeral 95. The shoulder 91 has a depth that essentially corresponds to the thickness of a cutting insert 15 to be clamped in place. With the cutting insert 15 inserted, the face of the cutting insert is thus essentially flush with the front wall section 95.

[0058] Within the scope of the present invention, groove 19 refers to those sections of the tool holder that contribute to the tool retention. Groove 19 therefore has first and second groove walls 27 and 31 of unequal length.

[0059] The rear wall section 93 of the first groove wall 27 above the step 91 can be slightly inclined inwards relative to the front wall section 95 and may assume an angle of up to 5 degrees (see Fig. 3 This allows the tool to be pre-tensioned even more strongly against the groove wall 27 in the front area.

[0060] The screw 29 for tightening and loosening the centrifugal wedge 23 is preferably designed as a threaded pin with a front and a rear threaded section 97 and 99 respectively ( Fig. 7At the rear, the screw has a drive point 101 for a tool, e.g., an internal square or hexagonal drive or a Torx® threaded drive. The front and rear threaded sections 97, 99 are separated from each other by a constriction 103. The front threaded section 97 is designed to engage with the internal thread 70 of the screw hole 69. The rear threaded section 99, on the other hand, is designed to engage with the internal thread 63 of the screw hole 57 formed in the centrifugal wedge 23. A special feature of the described screw connection is that the front and rear threaded sections 97, 99 have opposing threads. According to a preferred embodiment, the front threaded section 97 is a left-hand thread and the rear threaded section 99 is a right-hand thread. This has the advantage that the screw can be turned in the usual direction to tighten the centrifugal wedge.The radial position of the centrifugal wedge 23 changes by two thread turns with each full screw revolution.

[0061] Another modified embodiment of a centrifugal wedge 23 has a centering element 105 on the wedge surface 33 in the form of a centering knob projecting from the wedge surface 33 ( Fig. 8 The centering element 105 serves for the lateral centering of the component in the Figure 9 The depicted locking element 25a is secured by means of a positive locking mechanism. In contrast to the locking element 25, the locking element 25a has, according to Fig. 5 Instead of a recess 77 in the surface oriented towards the centrifugal wedge 23, only a U-shaped depression 107 is formed. This depression 107 extends in the center of the locking element 25a at a right angle from the base 109 of the locking element 25a (central axis 102). Further differences include the fact that the locking element 25a has no magnets or plastic studs.

[0062] The Figure 11 and 12 show a tool head 11a with the centrifugal wedge 23 and the locking element 25a according to Figure 9 In contrast to the first embodiment according to the Figures 1 to 7 The tool head 11a has a sleeve-shaped pressure element 113a, which is inserted into an enlarged, front pin hole section 115 of the pin hole 81. The upper edge of the pressure element 113a protrudes from the front wall section 95 on the groove side at the shoulder 91. As in Fig. 11 As shown, in the tool holder's changeover position, the pressure element 113a presses against the locking element 25a and pre-tensions it against the centrifugal wedge 23a. When the cutting insert 15 is clamped, the part of the elastically deformable pressure element 113a protruding from the wall section 95 is deformed and pushes the cutting insert 15 radially outwards and thus against the stop bar 85. This results in automatic radial centering of the cutting insert 15. As shown in Fig. 12 As can be seen, there is a play between the stop bar 85 and the recess 87, i.e., the recess 87 is wider than the stop bar 85 by a certain amount, preferably between 0.05 and 1.5 mm and particularly preferably between 0.3 and 1.0 mm. When the cutting insert 15 is loosely inserted into the tool holder and rests on the shoulder 91 ( Fig. 9 ), the upper edge 117 of the stop strip 85 can essentially correspond to the inner side edge 119 of the recess 87.

[0063] The embodiment according to the Figure 13 and 14 differs from that of the Figure 11 and 12The embodiment consists in at least one pressure element 113b, preferably two pressure elements 113b, being received in a separate blind hole 121 provided in the area of ​​the shoulder 91 in the tool head body. Preferably, one blind hole 121 and one pressure element 113b are provided symmetrically on each side of the centering pin 79. The function of the pressure element 113b is the same as that of the pressure element 113a, i.e., the part of the pressure element 113b protruding from the blind hole 121 and from the wall section 95 causes radial centering of the cutting insert 15 when clamped. A further modification of this embodiment is located in the area of ​​the lateral positioning of the cutting insert 15. The cutting insert 15 does not have a U-shaped recess for lateral positioning.For lateral positioning, the positioning pin 79 is moved axially outside the cutting plate 15, so that the cutting plate 15 can be struck against the positioning pin 79 either on the left or right side.

[0064] The Figure 15 and 16Figure 11 shows another tool head 11c in which the tool holder 13a represents a shallower cut than in the tool heads described above, and the cutting insert 15a has a low height and two cutting edges 92a, 92b. Accordingly, the locking element 25c is also shorter than in the other embodiments. Unlike the tool heads described above, tool head 11c has a stop bar 85a that is integral with the tool body. Furthermore, a centering pin is not centrally located; instead, a lateral stop is provided for the lateral centering of the cutting insert (not shown in the figures). Otherwise, tool head 11c is identical to the other tool heads in terms of function and construction, so a more detailed description is unnecessary.

[0065] The tool head 11d according to Figure 17This represents a flattening cutter head which differs from the previously described embodiments in that the tool holder 13 is not located on the circumference but on the end face 123 of the tool head 11d. Due to this design, the centrifugal forces generated when the tool head rotates act only to a small extent on the locking element 25 and the cutting insert 15. To nevertheless hold the centrifugal wedge 23 precisely in the groove 19, two spaced-apart reinforcing elements 125 projecting from the wall of the groove 31 are provided, which interact positively with corresponding grooves 127 in the centrifugal wedge 23.

[0066] For tool head 11e according to Fig. 18A modified clamping mechanism is shown. This differs from the one described above in that the clamping screw 29a has only a rear thread 99. A head 129 is provided on the front of the clamping screw 29a, which is supported on the base of the groove 65, 67. In addition, a centering projection 131 is formed on the head 129, which engages in the screw hole 60, which in this case does not need to have an internal thread. The centering projection can also be omitted, as it is not required for clamping the cutting insert. Furthermore, the described embodiment of a tool head does not include a locking element; instead, the centrifugal wedge 23 acts directly on the cutting insert 15.

[0067] The Figures 19 to 21 show an embodiment of a pressure element 133 which on the one hand performs the function of the centering bolt described above (see Fig. 3) for the lateral alignment of the cutting plate and, on the other hand, the pressure element for the radial positioning of the cutting plate. The pressure element 133 has a rear clamping section 135, comparable to a heavy-duty spring pin, which can be inserted into the pin hole 81. A spring tongue 137 with a terminal lug 139 is formed on the clamping section 135, which – when inserted into the pin hole 81 – projects beyond the front wall section 95. As in the Figs. 20 and 21 As shown, the spring tongue 137 presses with the nose 139 onto the locking element 25, pushes it away and thus facilitates the removal of the cutting plate 15 when the centrifugal wedge is released ( Fig. 21 ).

[0068] The tool head according to the invention is used as follows: To insert a new cutting insert into the tool head according to the Figures 1 to 3The centrifugal wedge 23 is first brought into contact with the bottom of the groove by turning the clamping screw as far as possible in the corresponding direction of rotation. In the tool-changing position then assumed, the centrifugal wedge 23 is tilted relative to the first groove wall 27, so that a gap opening in the radial direction is formed between the locking element 25 and the rear wall section 93 of the groove wall 27 ( Fig. 2The new cutting insert can now be inserted into the gap, with the centering pin 79 ensuring the correct lateral centering of the cutting insert 15. In this position, the cutting insert 15 rests against the shoulder 91. The elastically deformable pressure elements 73, 113a, 113b can also touch the base of the cutting insert or be positioned a short distance from it. When the screw 29 is turned in the clamping direction, the pressure elements 73, 113a, 113b are clamped between the front wall section 95 and the locking element. These expand laterally and push the cutting insert radially outwards, so that the lower edge 100 of the groove 87 rests against the stop bar 85. The position of the groove 87, and in particular the lower edge 100, relative to the base surface 108 of the cutting insert, plays an important role in this process.Only in this way is it ensured that the expansion of the pressure elements during tool clamping is sufficient to guarantee precise radial positioning of the cutting insert even during the clamping process. This ensures accurate radial positioning of the cutting insert, significantly increasing the precision of the work performed. Screw 29 is turned until the centrifugal wedge is firmly seated against the locking element 25. The centrifugal force generated by the rotating tool head further increases the clamping force.

[0069] The tool head according to the invention is particularly suitable for machining wood, plastics, and similar materials where the machining process and the removal of chips or particles are similar. Similar materials include, for example, cork, bone, plastics, light metal alloys, and wood-based materials such as particleboard, fiberboard, plywood, etc. Cutting inserts with a straight, convex, or profiled cutting edge are used as tools. The cutting inserts consist of flat blades with a thickness between approximately 1 mm and 3 mm. During operation, the cutter head is mounted on a spindle of a woodworking machine in a rotationally fixed manner, and additional cutter heads can be mounted directly adjacent to it on the spindle. According to one aspect of the invention, the adjustment of the centrifugal wedge (tightening and loosening) can be carried out by means of a single screw for all operating widths.In this process, the cutting plate is already pressed against the stop bar 85 in the direction of flight during clamping, so that the cutting plate can no longer move further when the tool head is rotating.

[0070] In the above description, the exemplary embodiments are each described using a circular-cylindrical tool head in cross-section, in which the tool is received in an axial groove (parallel to the axis of rotation). However, within the scope of the invention, the tool holder or groove can also run at an angle to the axis of rotation (e.g., a conical tool head). The groove can thus assume three spatial angles relative to the axis of rotation and thereby define a rake angle, a throw angle, and an axial angle. legend

[0071] 11, 11a-d Tool head 13 Tool holders 15 Cutting insert 17 Axis of rotation of the tool head 19 Groove 21 Profile knife 23 Centrifugal wedge 25 Locking element 27 First groove wall of the groove 29 Screw 31 Second groove wall of the groove 33 Front wedge surface 35 Back surface 37 Recess 39 First pressure surface 41 Second pressure surface 43 Bead on centrifugal wedge 23 47 Axial recess of the locking element 49 First bottom surface 51 Second bottom surface 53 Step 55 Slotted holes 57 Screw hole 59 Longitudinal axis 61 Top surface 63 Internal thread of the screw hole 57 65 First groove base surface 67 Second groove base surface 68 Magnet 69 Screw hole 70 Internal thread of the screw hole 69 71 Recess for receiving a magnet 68 73 Pressure element in the form of a stud 75 Holes in the locking element for receiving the studs 73 77 U-shaped recess in the locking piece 79 Centering pin 81 Pin hole 83 Groove for receiving the stop bar 85 85,85a Stop bar 87 Elongated recess in the cutting plate,Positioning groove 89 U-shaped recess in the cutting insert 90 Cutting insert face 91 Step of the first groove wall 92 Cutting edge 93 Rear wall section 94 Functional surface on the cutting insert 15 as chamfer or rounding 95 Front wall section of the groove 19 97 Front thread section of the groove 19 99 Rear thread section 100 Lower edge of the groove 87 101 Engagement means on the screw 29 102 Central axis 103 Reduction on the screw 29 105 Centering element, centering knob on the centrifugal wedge 23 107 Recess in the locking element 25a 108 Base surface of the cutting insert 109 Base of the locking element 25,25a 111 Central axis of the locking element 25a 113a,113bVarious designs of the pressure element 115Extended pin hole section 117Upper edge of the stop bar 85 119Upper edge of the groove 87 121Blind hole for pressure element 113b 123End face of the tool head 11d 125Reinforcing elements for flattening cutter head 127Grooves in the centrifugal wedge 23 for receiving the reinforcing elements 125 129Head of the clamping screw 29a 131Centering extension 133Pressure element 135Clamping section 137Spring tongue 139Nose of the spring tongue

Claims

1. A tool head (11a-d, f) for a woodworking machine, with a cylindrical, conical or profiled base body for the rotating machining of a workpiece, which comprises at least two tool holders, preferably arranged uniformly distributed over its circumference, wherein the tool holders (13) each have a groove (19), in each of which a cutting insert (15) can be clamped in the gap between a first groove wall (27) of the groove (19) and a closure element (25) serving as a pressure jaw, further characterised by a stop (85, 85a) provided in the first groove wall (27) and a pressure element (73; 113a, 113b; 133) provided on the tool body and made of an elastic plastic or a spring-elastic metal, which is suitable and positioned in such a way that it acts on the cutting insert (15) in a radial direction when the cutting insert is clamped and automatically presses the latter radially outwards against the stop (85, 85a) on the first groove wall (27).

2. The tool head (11a-d, f) according to claim 1 or 2, characterised in that the stop (85, 85b) is a stop bar (85), which is admitted in a form-fitting manner in a groove (83) of the first groove wall (27) or which is integral with the tool body.

3. The tool head (11a-d, f) according to any one of claims 1 to 3, characterised in that the stop bar (85, 85b) in the clamping position interacts with a groove (87) in the cutting insert (15) for the purpose of precise positioning and this groove (87) is a certain distance, preferably by 5% and particularly preferably by at least 10% wider than the stop bar (85, 85b).

4. The tool head (11a-d, f) according to any one of claims 1 to 4, characterised in that the pressure element (73; 113a, 113b; 133) is a spring or an elastically deformable plastic or metal part.

5. The tool head (11a-d, f) according to any one of claims 1 to 5, characterised in that the pressure element (73; 113a, 113b; 133) is arranged where the lower base (108) of the cutting insert (15) rests on a ledge (91) of the tool holder, so that the pressure element (73; 113a; 113b; 133) can interact with the lower base (108) of the knife insert (15).

6. The tool head (11a-d, f) according to any one of claims 1 to 6, characterised in that the pressure element (113b; 133) is arranged in a hole (81, 121) of the tool head.

7. The tool head (11a-d, f) according to any one of claims 1 to 7, characterised in that the pressure element (113a) is sleeve-shaped and inserted into a widened front pin hole portion (115) of a pin hole (81), wherein the sleeve-shaped pressure element is arranged on a pin (79) in the tool head.

8. The tool head (11a-d, f) according to any one of claims 1 to 6, characterised in that the pressure element (73) is provided or formed on the closure element (25).

9. The tool head (11a-d, f) according to any one of claims 1 to 7, characterised in that the pressure element (133) engages in a recess (89) of the cutting insert (15) to be clamped.

10. A method for positioning a cutting insert (15) in a tool holder of a tool head (11a-d, f) with a cylindrical, conical or profiled base body for rotating machining of a workpiece, wherein the tool holder comprises a groove (19) in each case, in which a cutting insert can be clamped in each case between a first groove wall (27) of the groove (19) and a closure element (25) serving as a pressure jaw, characterised in that a cutting insert (15) inserted into the tool holder is pushed radially outwards against a stop (85, 85a) in a form-fitting manner with the aid of an elastic pressure element (73; 113a, 113b; 133) during the clamping process.

11. The method according to claim 11, characterised in that the cutting insert (15) is pressed radially outwards against a stop (85) before reaching the final clamping position.

12. The method according to claim 11 or 12, characterised in that the cutting insert (15) is automatically positioned radially outwards with the aid of the elastic pressure element (73; 113a, 113b; 133).

13. The method according to any one of claims 11 to 13, characterised in that the radial and lateral positioning takes place automatically when the cutting insert (15) is clamped.

14. The method according to any one of claims 11 to 14, characterised in that the cutting insert (15) is additionally tilted when the clamping mechanism is released.

15. The method according to any one of claims 11 to 15, characterised in that the cutting insert (15) in the change position is pressed by the pressure element (73; 113a, 113b) against the closure element (25).

16. The method according to any one of claims 11 to 16, characterised in that in the tool change position the cutting insert (15) is released by tilting.

17. The method according to claim 17, characterised in that in the tool change position the lower edge (100) of the groove (87) in the cutting insert (15) is tilted by an angle of > 90° with respect to the first groove wall (27).