TOOL HEAD AND METHOD FOR INSERTING AND CLAMPING A CUTTING INSERT, AND CUTTING INSERT

Abstract

The invention relates to a tool head for a woodworking machine, having a cylindrical, conical or profiled main part, which has at least two tool-receiving portions evenly distributed across its circumference for holding the cutting insert. The tool-receiving portions each have grooves tapering in the radial direction, in which one cutting insert per groove is clamped between a first side wall of the groove and a closing element. A first interlocking connection is provided between the cutting insert and the first side wall. In addition, a centrifugal wedge is arranged between the closing element and a second side wall situated opposite the first side wall of the groove. According to the invention, a second interlocking connection is provided between the closing element and the centrifugal wedge. This permits radial insertion of a cutting insert.

Claims

1. A tool head for a woodworking machine having a cylindrical, conical or profiled main part, comprising: at least two tool mounts, each of the at least two tool mounts comprising: a groove that tapers in a radial direction so as to be wider at a base of the groove, the groove having a first side wall and a second side wall, the first side wall having a first locking connection; a cutting insert abutting the first side wall of the groove, the cutting insert defining a second locking connection on a first side thereof and having a planar second side, the second locking connection engaging with the first locking connection to retain the cutting insert relative to the first side wall; a closure element having a planar first side abutting against the planar second side of the cutting insert and having a third locking connection on a second side thereof; and a centrifugal wedge positioned between the closure element and the second side wall opposite the first side wall, the centrifugal wedge having a fourth locking connection on a first side thereof, the fourth locking connection engaging with the third locking connection of the closure element, the centrifugal wedge abutting against the second side of the closure element; wherein the centrifugal wedge applies a clamping force against the closure element and the cutting insert to hold the second locking connection of the cutting insert to the first locking connection of the first side wall, wherein the centrifugal wedge increases the clamping force against the closure element and the cutting insert resulting from a centrifugal force applied to the centrifugal wedge when the tool head is rotated during use and wherein the centrifugal wedge is moveable radially inward and into a tool change position by turning the clamping screw in a second, opposite direction until the cutting insert can be disengaged from the first side wall and be radially removed from the groove.

2. The tool head according to claim 1, wherein the centrifugal wedge has a hole with an internal thread into which a clamping screw is introduced, wherein the centrifugal wedge is movable radially outward into a clamping position by turning the clamping screw in a first direction to lock the cutting insert to the first side wall and the closure element to the centrifugal wedge and can be moved into the tool change position by turning the clamping screw in a second, opposite direction.

3. The tool head according to claim 1, wherein the base of the groove defines a screw hole with an internal thread and the shank of the clamping screw has two threaded portions with opposite screw threads, one threaded portion cooperating with the internal thread of the screw hole and the other threaded portion cooperating with the internal thread of the hole.

4. The tool head according to claim 1, wherein the closure element or the centrifugal wedge is provided with at least one magnet.

5. The tool head according to claim 1, further comprising a spring element positioned to act in the radial direction on the cutting insert to press the cutting insert against a stop before reaching a final clamping position.

6. A method for inserting and clamping a cutting insert in a mount of a tool head, comprising: introducing a cutting insert into a gap between a first side wall of a groove and a closure element, the groove tapering in a radial direction so as to be wider at a base of the groove; producing a first positive locking connection between the cutting insert and the first side wall of the groove; clamping the cutting insert with a centrifugal wedge; and producing a second positive locking connection between the closure element and the centrifugal wedge when the closure element is inserted into the tool mount, wherein the cutting insert is locked to the first positive locking connection to the first side wall and the closure element is locked to the centrifugal wedge by the second positive locking connection, with the closure element forcing the cutting insert into engagement with the first positive locking connection between the cutting insert and the first side wall; wherein a first side of the cutting insert abuts the first side wall of the groove such that a first locking connection of the side wall engages with a second locking connection of the first side of the cutting insert and wherein a second side of the cutting insert is planar; wherein the closure element has a planar first side abutting against the planar second side of the cutting insert and has a third locking connection on a second side thereof; and wherein the centrifugal wedge is positioned between the closure element and the second side wall opposite the first side wall of the groove, the centrifugal wedge having a fourth locking connection on a first side thereof, the fourth locking connection engaging with the third locking connection of the closure element, the centrifugal wedge abutting against the second side of the closure element. wherein the centrifugal wedge has a hole with an internal thread into which a clamping screw is introduced, wherein the centrifugal wedge is moveable radially outward into a clamping position by turning the clamping screw in a first direction to lock the cutting insert to the first side wall and the closure element to the centrifugal wedge, with the centrifugal wedge applying a clamping force to the closure element and the cutting insert to hold the second locking connection of the cutting insert to the first locking connection of the first side wall, wherein the centrifugal wedge increases the clamping force against the closure element and the cutting insert resulting from a centrifugal force applied to the centrifugal wedge when the tool head is rotated during use and wherein the centrifugal wedge is moveable radially inward and into a tool change position by turning the clamping screw in a second, opposite direction until the cutting insert can be disengaged from the first side wall and be radially removed from the groove.

7. The method according to claim 6, wherein the centrifugal wedge has a hole with an internal thread into which a clamping screw is introduced, wherein the centrifugal wedge is moveable radially outward into a clamping position by turning the clamping screw in a first direction to lock the cutting insert to the first side wall and the closure element to the centrifugal wedge, with the centrifugal wedge applying a clamping force to the closure element and the cutting insert to hold the second locking connection of the cutting insert to the first locking connection of the first side wall, wherein the centrifugal wedge increases the clamping force against the closure element and the cutting insert resulting from a centrifugal force applied to the centrifugal wedge when the tool head is rotated during use and wherein the centrifugal wedge is moveable radially inward and into a tool change position by turning the clamping screw in a second, opposite direction until the cutting insert can be disengaged from the first side wall and be radially removed from the groove.

8. The method according to claim 6, further comprising pressing the cutting insert against a stop before reaching a final clamping position.

9. The method according to claim 6, further comprising automatically positioning the cutting insert radially with a resilient pressure element when clamping.

10. A tool system having a tool head for a woodworking machine having a cylindrical, conical or profiled main part with a tool mount defining a groove that tapers in a radial direction so as to be wider at a base of the groove, the groove having a first side wall and a second side wall, the first side wall having a first locking connection, a closure element having a planar first side abutting against the planar second side of the cutting insert and having a third locking connection on a second side thereof, and a centrifugal wedge positioned between the closure element and the second side wall opposite the first side wall, the centrifugal wedge having a fourth locking connection on a first side thereof, the fourth locking connection engaging with the third locking connection of the closure element, the centrifugal wedge abutting against the second side of the closure element, the centrifugal wedge applying a clamping force against the closure element and the cutting insert to hold the second locking connection of the cutting insert to the first locking connection of the first side wall, wherein the centrifugal wedge increases the clamping force against the closure element and the cutting insert resulting from a centrifugal force applied to the centrifugal wedge when the tool head is rotated during use and wherein the centrifugal wedge is moveable radially inward and into a tool change position by turning the clamping screw in a second, opposite direction until the cutting insert can be disengaged from the first side wall and be radially removed from the groove, comprising: a cutting insert abutting the first side wall of the groove, the cutting insert defining a second locking connection on a first side thereof and having a planar second side, the second locking connection engaging with the first locking connection to retain the cutting insert relative to the first side wall, the cutting insert comprising a cutting edge along a top edge of a first side thereof, the first side thereof being flat and having a longitudinally extending recess forming a positioning channel along a second side thereof, the longitudinally extending recess configured to engage with and be held relative to the tool head and having a bottom edge diagonally opposite the cutting edge defining a surface in the form of one of a bevel or a rounding, wherein the cutting insert is configured to be locked to a first positive locking connection to a first side wall of the groove with a surface of a closure element abutting the first side of the cutting insert to force the cutting insert into engagement with the first positive locking connection between the cutting insert and the first side wall;

11. The tool system according to claim 10, wherein the bevel is greater than 0.6 mm, as seen in the cutting insert thickness.

12. The tool system according to claim 10, wherein the positioning channel is between 30% and 60% wider than a stop ledge provided in the tool mount.

13. The tool system according to claim 10, wherein the positioning channel can be angular, semicircular or V-shaped

14. The tool system according to claim 10, wherein only a single positioning channel is provided, the lower edge of which is located in a distance of less than 10 mm from the base surface of the cutting inserts.

15. The tool system according to claim 10, wherein the cutting insert comprises a U-shaped recess for lateral positioning.

16. The tool system according to claim 10, wherein the cutting insert does not include a U-shaped recess and further comprising a positioning pin arranged such that the cutting insert can be struck either on the left-hand side or on the right-hand side of the positioning pin.

17. The tool system according to claim 10, wherein the cutting insert comprises a flat blade with a thickness between about 1 mm and 3 mm.

18. A cutting insert for a tool head of a woodworking machine, comprising: an elongate plate having a cutting edge along a top edge of a first side of the elongated plate and a bottom edge diagonally opposite the cutting edge defining a surface in the form of one of a bevel or a rounding, the depth of which is at least 15% of a thickness of the elongate plate, the first side of the elongate plate being planar and a second side of the elongate plate defining a longitudinally extending recess along a second side of the elongate plate, the longitudinally extending recess configured to engage with and be held relative to the tool head, the tool head comprising: at least two tool mounts, each of the at least two tool mounts comprising: a groove that tapers in a radial direction so as to be wider at a base of the groove, the groove having a first side wall and a second side wall, the first side wall having a first locking connection; a closure element having a planar first side abutting against the planar side of the elongate plate and having a third locking connection on a second side thereof; and a centrifugal wedge positioned between the closure element and the second side wall opposite the first side wall, the centrifugal wedge having a fourth locking connection on a first side thereof, the fourth locking connection engaging with the third locking connection of the closure element, the centrifugal wedge abutting against the second side of the closure element, the centrifugal wedge applying a clamping force against the closure element and the elongate plate to hold the second locking connection of the elongate plate to the first locking connection of the first side wall, wherein the centrifugal wedge increases the clamping force against the closure element and the elongate plate resulting from a centrifugal force applied to the centrifugal wedge when the tool head is rotated during use and wherein the centrifugal wedge is moveable radially inward and into a tool change position by turning the clamping screw in a second, opposite direction until the elongate plate can be disengaged from the first side wall and be radially removed from the groove, wherein the centrifugal wedge has a hole with an internal thread into which a clamping screw is introduced, wherein the centrifugal wedge is movable radially outward into a clamping position by turning the clamping screw in a first direction to lock the elongate plate to the first side wall and the closure element to the centrifugal wedge and can be moved into a tool change position by turning the clamping screw in a second, opposite direction, the elongate plate abutting the first side wall of the groove, the second locking connection of the elongate plate engaging with the first locking connection to retain the elongate plate relative to the first side wall, wherein the elongate plate is configured to be locked to a first positive locking connection to a first side wall of the groove with a flat surface of a closure element abutting the second side of the elongate plate to force the elongate plate into engagement with the first positive locking connection between the elongate plate and the first side wall.

19. The cutting insert according to claim 18, wherein the positioning channel can be angular, semi-circular or V-shaped.

20. The cutting insert according to claim 18, wherein the bevel comprises at least 0.6 mm of the cutting insert thickness.

21. The cutting insert of claim 18, wherein only a single positioning channel is provided, the lower edge of which is at a distance of less than 10 mm from the base surface of the cutting insert.

22. The cutting insert of claim 18, wherein for lateral positioning, the cutting insert defines a U-shaped recess.

23. The cutting insert of claim 18, wherein for lateral positioning the cutting insert can be struck either on a left-hand side or on a right-hand side of a positioning pin if the cutting insert does not include a U-shaped recess.

Description

[0047] Embodiments of the invention will now be described in more detail with reference to the following figures, in which:

[0048] FIG. 1: is a partial side view of a first embodiment of an individual tool mount of a tool head with a cutting insert clamped by a closure element and a centrifugal wedge (working position);

[0049] FIG. 2: is a view as in FIG. 1, the cutting insert being in the change position;

[0050] FIG. 3: is a side view of the entire tool head, the cutting insert being in the change position;

[0051] FIG. 4: is a front view and a side view of the centrifugal wedge;

[0052] FIG. 5: is a front elevation view and a side view of the closure element;

[0053] FIG. 6: is a front elevation view and a side view of a cutting insert configured as a (moulding) knife;

[0054] FIG. 7: shows a screw with two threaded portions for clamping and releasing the centrifugal wedge;

[0055] FIG. 8: shows a further embodiment of a centrifugal wedge according to the invention;

[0056] FIG. 9: shows a further embodiment of a closure element according to the invention with a cross channel at a distance from the base of the blade and with a positioning aid;

[0057] FIG. 10: is a front elevation view and a side view of two further embodiments of a cutting insert in the form of a moulding knife, the cutting inserts differing in the elongate recesses;

[0058] FIG. 11: is a partial view of a second embodiment of an individual tool mount of a tool head with a centrifugal wedge according to FIG. 8 and with a resilient pressure element for positioning the cutting insert in the tool change position;

[0059] FIG. 12: shows the tool head of FIG. 11 with the cutting insert in the (clamped) working position;

[0060] FIG. 13: is a partial view of a third embodiment of an individual tool mount of a tool head with a modified pressure element and a short closure element; and

[0061] FIG. 14: shows the tool head of FIG. 13 with the cutting insert in the (clamped) working position;

[0062] FIG. 15: is a partial view of a fourth embodiment of an individual tool mount of a scraper tool head with a short cutting insert;

[0063] FIG. 16: shows the tool head of FIG. 15 with the cutting insert in the tool change position;

[0064] FIG. 17: shows a further embodiment of a tool head in the form of a flattening cutter head;

[0065] FIG. 18: shows an additional embodiment of a tool head, in which the clamping screw is a clamping pin which is supported by its head on the base of the groove;

[0066] FIG. 19: shows an embodiment of a spring element which ensures the radial positioning of the cutting insert when the tool is clamped;

[0067] FIG. 20: is an enlarged detail view of the spring element of FIG. 19 when it has been inserted into the tool mount and the cutting insert is clamped by the centrifugal wedge;

[0068] FIG. 21: is also an enlarged view of the spring element of FIG. 19 when the cutting insert has been introduced into the tool mount and the centrifugal wedge is released.

[0069] FIGS. 1 to 7 show a tool head 11 according to the invention for the rotating machining of wood and the components thereof. It has a plurality of tool mounts 13 which are distributed over the circumference and in which a respective tool in the form of a cutting insert 15 can be received. Provided in the tool mount 13 is a groove 19 which tapers in the radial direction and which can run axially parallel or at an angle to the rotational axis 17 of the tool head 11. A centrifugal wedge 23 and a closure element 25 are used to clamp the cutting insert 15 which, in the illustrated example, is formed by a moulding knife 21 (FIG. 6). The closure 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. Thus, the cutting insert is clamped between a first groove wall 27 of the tool head 11 and the closure element 25 in the working or clamping position. The tool head according to the invention is distinguished in that the cutting insert can be inserted into and removed from the tool mount 13 in the radial direction. Furthermore, the closure element 25 is held in the tool mount 13 without screws. A further distinctive feature is that the centrifugal wedge 23 is clamped and released by a single screw 29 for all widths within the application field according to the invention (typically between 7 mm and 150 mm, or between 15 and 100 mm), i.e. a hammer is no longer required to release the tool holder, as is usually the case for conventional tool heads. The aforementioned distinctive features of the tool head according to the invention will be explained in more detail in the following description.

[0070] As mentioned above, the groove 19 tapers outwards in a wedge shape in the radial direction, i.e. the first groove wall 27 and a second groove wall 31 opposite the first groove wall 27 are inclined with respect to one another. The centrifugal wedge 23 is received in the groove 19. The configuration of the centrifugal wedge 23 and of the groove 19 is such that the centrifugal wedge can be inserted into the groove 19 in the radial direction when the closure element 25 is not present. However, it is also conceivable that the configuration of the centrifugal wedge 23 and of the groove 19 is such that only a lateral insertion is possible. Both embodiments are equally possible within the scope of the present invention.

[0071] The centrifugal wedge 23 has a front wedge surface 33 which rests against the closure element 25, and a rear surface 35 which rests in a planar manner on the second groove wall 31. If the closure element is not provided, the front wedge surface 33 rests directly on the cutting insert. The front wedge surface 33 is interrupted by a recess 37 which extends in the longitudinal direction of the centrifugal wedge 23, so that a first contact surface 39 is present above the recess 37 and a second contact surface 41 is present below the recess. The second contact surface 41 has an elevation 43 in the form of a bead which extends in the longitudinal direction and allows a positive locking connection with a corresponding, complementarily formed recess 47 in the closure element 25.

[0072] The base of the centrifugal wedge 23 is step-shaped so that a first base surface 49 is present adjoining the front wedge surface 33 and a second base surface 51 is present adjoining the rear surface 35. The first and second base surfaces 49, 51 are separated by a step 53 which extends substantially parallel to the rear surface 35. In this respect, the second base surface 51 includes an angle of 90 degrees or more, or between 91 and 93 degrees, with the rear surface 35. This can cause the centrifugal wedge 23 to tilt in the change position, as will be explained in more detail further below.

[0073] In order to reduce weight, one or more spaced-apart slots 55 can be provided in the centrifugal wedge 23. Located between the slots 55 is a screw hole 57 with a longitudinal axis 59, which screw hole extends from the top surface 61 to the second base surface 51. The longitudinal axis 59 of the screw hole 57 extends substantially parallel to the rear surface 35. The screw hole 57 has an internal thread 63 to receive a rear threaded portion 99 of the screw 29 (FIG. 7).

[0074] The base of the groove is also step-shaped analogously to the base surface 49, 51 of the centrifugal wedge 23. 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 60 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 closure element 25 and the cutting insert 15 are pressed firmly against the first groove wall 27, into a lower tool change position in which the cutting insert 15 can be removed in the radial direction.

[0075] As mentioned above, while the base surface 51 includes an angle of 90 degrees with the rear surface 35, the angle between the first groove base surface 65 and the rear surface 31 is approximately 90 degrees. If the base surface 51 includes an angle of >90 degrees with the rear surface 35, when the tool mount is opened, the second base surface 51 of the centrifugal wedge 23 near the step 53 thus firstly comes into contact with the first groove base surface 65. Consequently, on reaching the tool change position, a transverse force acts on the centrifugal wedge 23, which transverse force causes the centrifugal wedge 23 to tilt due to the existing tolerances of the screw thread (FIG. 2). In so doing, the closure element 25 and the cutting insert 15 are released from the first side wall 27.

[0076] A distinctive feature of the closure element 25 is that at least one, but or two or more magnets 69 are provided in the lower region (FIG. 5). These are received in openings 71 flush with the adjoining surface of the tool. The magnets 69 serve to hold the cutting inserts 15, consisting of a generally weakly magnetisable material, such that they adhere to the closure element 25, particularly during a tool change, so that the tool can be removed relatively easily.

[0077] Two elastically deformable plastics nubs 73, in particular those of an elastomeric material, are provided in the closure element 25 at a distance from one another just above the recess 47. These nubs can be introduced into corresponding holes 75 in the closure element 25. The purpose of the nubs 73 is to push the cutting insert 15 upwards during the clamping procedure. The mode of operation of the nubs 73 is described in more detail further below.

[0078] A U-shaped recess 77 in the centre of the rear fixing portion is provided for the lateral centring of the closure element 25 in the groove 19. Engaging in this recess 77 in the clamping position is an axially adjustable centring pin 79 which is received in a pinhole 81 in the body of the tool head (FIGS. 1 to 3). The pinhole 81 is worked into the tool head body at an angle to the first groove wall 27.

[0079] A single channel 83 is provided in the first groove wall 27 just above the pinhole 81. A stop ledge 85 is received positively in this channel 83. The channel 83 and the corresponding stop ledge 85 can be four-sided or polygonal or round in cross section. In the clamping position, the stop ledge 85 cooperates with a groove 87 in the cutting insert 15 for accurate positioning (FIG. 6). This groove 87 is wider than the stop ledge 85 by a particular distance, by at least 5% or by at least 10%. The groove 87 is advantageously between 20 and 80% wider than the stop ledge. In specific embodiments, the groove 87 is between 30% and 60% wider than the stop ledge 85. It is conceivable that instead of the stop ledge 85, a corresponding elongate stop 85a is formed directly in the groove wall 27.

[0080] The cutting insert 15 which, according to FIG. 6, is configured as a moulding knife 21, can have in the centre in the base of the tool and analogously to the closure element 25, a U-shaped recess 89 which is used to centre the cutting insert 15. When the cutting insert 15 is introduced into the groove 19, the head of the centring pin 79 engages in the U-shaped recesses 77, 89 in the closure element 25 and in the cutting insert 15 so that they come to rest exactly one above the other. Formed on the front 90 of the cutting insert is a cutting edge 92. A functional surface in the form of a bevel 94 is formed on the edge diagonally opposite the cutting edge 92.

[0081] As can be seen in FIGS. 1 to 3, the first groove wall 27 is not a straight surface, but it has at a distance from the base of the groove a shoulder 91 against which the cutting insert can rest. Here, the rear (set-back) wall portion above the shoulder 91 is identified by reference numeral 93 and the front (upstream) wall portion is identified by reference numeral 95. The shoulder 91 has a depth which substantially corresponds to the thickness of a cutting insert 15 to be clamped. Thus, when a cutting insert 15 has been introduced, the front thereof is substantially flush with the front wall portion 95.

[0082] Within the context of the present invention, those portions of the tool mount which cooperate in the tool mounting are referred to as groove 19. According thereto, the groove 19 has first and second groove walls 27 and 31 which differ in length.

[0083] The rear wall portion 93 of the first groove wall 27 above the shoulder 91 can be slightly inclined inwards relative to the front wall portion 95 and can include an angle of up to 5 degrees (see FIG. 3). Consequently, the tool can be pretensioned to an even greater extent against the groove wall 27 in the front region.

[0084] The screw 29 for clamping and releasing the centrifugal wedge 23 is configured as a threaded pin having a front and a rear threaded portion 97 and 99 respectively (FIG. 7). At the back, the screw has an engagement means 101 for a tool, for example a square socket or a hexagon or a Torx thread. The front and rear threaded portions 97, 99 are separated from each other by a narrowing 103. The front threaded portion 97 is configured to cooperate with the internal thread 70 of the screw hole 69. The rear threaded portion 99 is configured to cooperate with the internal thread 63, formed in the centrifugal wedge 23, of the screw hole 57. A distinctive feature of the described screw connection is that the front and rear threaded portions 97, 99 have opposite screw threads. According to one embodiment, the front threaded portion 97 is a left-hand thread and the rear threaded portion 99 is a right-hand thread. This has the advantage that in order to clamp the centrifugal wedge, the screw can be turned in the usual direction. In so doing, the radial position of the centrifugal wedge 23 changes during a full screw rotation just by two thread turns.

[0085] A further modified embodiment of a centrifugal wedge 23 has on the wedge surface 33 a centring element 105 in the form of a centring nub which projects out of the wedge surface 33 (FIG. 8). The centring element 105 is used to laterally centre the closure element 25a, shown in FIG. 9, by positive locking. Unlike the closure element 25 according to FIG. 5, the closure element 25a merely has a U-shaped recess 107, instead of a recess 77 in the surface oriented towards the centrifugal wedge 23. This recess 107 extends in the centre of the closure element 25a at a right angle from the base 109 of the closure element 25a (centre axis 102). Further differences are that the closure element 25a does not have any magnets or plastics nubs.

[0086] FIGS. 11 and 12 show a tool head 11a with the centrifugal wedge 23 and the closure element 25a according to FIG. 9. Unlike the first embodiment according to FIGS. 1 to 7, the tool head 11a has a sleeve-shaped pressure element 113a which is inserted into a widened, front pinhole portion 115 of the pinhole 81. The upper edge of the pressure element 113a projects out of the front wall portion 95 on the groove-side at the shoulder 91. As shown in FIG. 11, in the change position of the tool mount, the pressure element 113a presses against the closure element 25a and pretensions it against the centrifugal wedge 23. During clamping of the cutting insert 15, the part, projecting out of the wall portion 95, of the elastically deformable pressure element 113a is deformed and presses the cutting insert 15 radially outwards and thus against the stop ledge 85. Consequently, the cutting insert 15 is centred automatically in the radial direction. As can be seen in FIG. 12, there is a clearance between the stop ledge 85 and the recess 87, i.e. the recess 87 is wider than the stop ledge 85 by a particular amount, between 0.05 and 1.5 mm or between 0.3 and 1.0 mm. When the cutting insert 15 is loosely introduced into the tool mount and rests on the shoulder 91 (FIG. 9), the upper edge 117 of the stop ledge 85 can substantially correspond to the inner side edge 119 of the recess 87.

[0087] The embodiment according to FIGS. 13 and 14 differs from that of FIGS. 11 and 12 in that at least one pressure element 113b, or two pressure elements 113b is/are received in a separate blind hole 121 which is provided in the region of the shoulder 91 in the body of the tool head. A respective blind hole 121 and a pressure element 113b are provided symmetrically on both sides of the centring pin 79. The mode of operation of the pressure element 113b is the same as that of pressure element 113a, i.e. the part of the pressure element 113b protruding out of the blind hole 121 and out of the wall portion 95 causes a radial centring of the cutting insert 15 during clamping. A further modification of this embodiment is found in the region of the lateral positioning of the cutting insert 15. The cutting insert 15 does not have a U-shaped recess for the lateral positioning. For lateral positioning, the positioning pin 79 is moved axially outside the cutting insert 15, so that the cutting insert 15 can be struck either on the left-hand side or on the right-hand side of the positioning pin 79.

[0088] FIGS. 15 and 16 show a further tool head 11c, in which the tool mount 13a forms a less deep indentation than in the case of the tool heads described above and the cutting insert 15a only has a small height and has two cutting edges 92a, 92b. Accordingly, the closure element 25c is also shorter than in the other embodiments. Unlike the tool heads described above, the tool head 11c has a stop ledge 85a which is integral with the tool body. Furthermore, a centring pin is not arranged centrally, but a lateral stop is provided for the lateral centring of the cutting insert (not shown in the figures). Otherwise, the tool head 11c conforms with the other tool heads in respect of function and construction, so that a more detailed description is unnecessary.

[0089] The tool head 11d according to FIG. 17 is a flattening cutter head which differs from the embodiments described hitherto in that the tool mount 13 is not provided in the circumference, but in the end face 123 of the tool head 11d. Due to this construction, the centrifugal forces which are generated as the tool head rotates still only slightly act on the closure element 25 and on the cutting insert 15. To nevertheless accurately hold the centrifugal wedge 23 in the groove 19, there are provided in the groove wall 31 two spaced-apart reinforcing elements 125 which project out of the wall and cooperate positively with corresponding channels 127 in the centrifugal wedge 23.

[0090] A modified clamping mechanism is shown in the case of the tool head 11e according to FIG. 18. This clamping mechanism differs from those described above in that the clamping screw 29a only has a rear thread 99. Provided on the front of the clamping screw 29a is a head 129 which is supported on the base 65, 67 of the groove. Furthermore, formed on the head 129 is a centring extension 131 which engages in the screw hole 60 which, in this case, does not have to have an internal thread. In principle, the centring extension can also be omitted, as it is not required for clamping the cutting insert. Furthermore, in the described embodiment of a tool head, a closure element is not provided, but the centrifugal wedge 23 acts directly on the cutting insert 15.

[0091] FIGS. 19 to 21 show an embodiment of a spring element 133 which, on the one hand, assumes the function of the centring pin described above (see FIG. 3) for the lateral orientation of the cutting insert and on the other hand assumes the function of the pressure element for the radial positioning of the cutting insert. The spring element 133 has a rear clamping portion 135, comparable to a heavy type dowel pin, which can be inserted into the pinhole 81. Formed on the clamping portion 135 is a flexible tongue 137 with an end nose 139 which, when inserted into the pinhole 81, projects over the front wall portion 95. As shown in FIGS. 20 and 21, the flexible tongue 137 presses by the nose 139 on the closure element 25, presses it away and thus facilitates the removal of the cutting insert 15 when the centrifugal wedge is released (FIG. 21).

[0092] The tool head according to the invention is used as follows: to introduce a new cutting insert into the tool head according to FIGS. 1 to 3, the centrifugal wedge 23 is firstly brought against the base of the groove by turning the clamping screw as far as possible in the appropriate direction of rotation. In the tool change position which is then assumed, the centrifugal wedge 23 is tilted relative to the first groove wall 27, so that a radially opening gap is formed between the closure element 25 and the rear wall portion 93 of the groove wall 27 (FIG. 2). The new cutting insert can then be introduced into the gap, the centring pin 79 ensuring the correct lateral centring of the cutting insert 15. In the then assumed position, the cutting insert 15 rests against the shoulder 91. The elastically deformable pressure elements 73, 113a, 113b can also contact the base of the cutting insert or can be arranged at a short distance therefrom. If the screw 29 is then turned in the clamping direction, the pressure elements 73, 113a, 113b are clamped between the front wall portion 95 and the closure element. These expand laterally and push the cutting insert radially outwards, so that the cutting insert rests on the stop ledge 85 with the lower edge 100 of the groove 87. In this respect, the position of the groove 87 and especially the position of the lower edge 100 based on the base 108 of the cutting insert play an important part. Only in this way is it ensured that the expansion of the pressure elements is sufficient during the clamping of the tool to ensure an exact positioning of the cutting insert in the radial direction during the clamping procedure. This measure ensures an exact positioning of the cutting insert in the radial direction, which significantly increases the accuracy of the work which is to be carried out. The screw 29 is turned until the centrifugal wedge rests firmly against the closure element 25. The clamping force is intensified by the centrifugal force which is generated during the use of the rotating tool head.

[0093] The tool head according to the invention is used in particular for machining wood, plastics and similar materials, for which the method when machining and removing chips or particles is similar. Similar materials are, for example cork, bone, plastics, light metal alloys, wood materials such as chipboard, fibreboard, plywood etc. Cutting inserts having a straight, curved or profiled cutting edge are used as the tools. The cutting inserts consist of flat blades which are between approximately 1 mm and 3 mm thick. During operation, the cutter head is arranged in a rotatably fixed manner on a spindle of a woodworking machine, it being possible for further cutter heads to be attached to the spindle in a directly adjacent position. According to one aspect of the invention, the centrifugal wedge can be adjusted (clamped and released) by a single screw for all scopes of application. In this respect, the cutting insert is pressed onto the stop ledge 85 in the flight direction during clamping, so that the cutting insert cannot move any further as the tool head rotates.

[0094] In the above description, the embodiments are respectively described by way of example on the basis of a tool head which is circular cylindrical in cross section and in which the tool is received in an axial groove (axially parallel to the rotational axis). However, within the scope of the invention, the tool mount or respectively groove can also extend at an angle to the rotational axis (for example, conical tool head). Thus, the groove can be at 3 spatial angles relative to the rotational axis and can thereby define a rake angle, an offset angle and an axis angle.