processing machine

Abstract

Machine tool (10), in particular a router, with a shaft (70) which can be driven to rotate about an axis of rotation, a tool holder (60) which is coupled to the shaft (70) for driving purposes or is formed integrally with it, and a clamping device for detachably fastening a tool (90) in the tool holder (60), wherein the clamping device comprises: - at least one clamping element held on the tool holder, which has a central passage for guiding a tool (90) to be inserted into the tool holder (60), wherein the clamping element is deformable by axial force and the width of the passage can be changed by this deformation, and - a clamping element (40) mounted on the tool holder, which is displaceable in the axial direction between a clamping position and a release position, wherein the clamping element (40) can be axially actuated by moving it in the direction of the clamping position, characterized in that the clamping element is a clamping sleeve (50) which can be detachably locked on the tool holder (60) and which has a reduction in the width of the passage (52) by moving the clamping element (40) in the direction of the clamping position.

Description

[0001] The invention relates to a machining machine, in particular a milling machine, according to the preamble of claim 1. Background of the invention

[0002] These machining tools are used with various tools, such as milling cutters, drills, and the like. The shanks of these tools have different diameters.

[0003] A processing machine of this type is known, for example, from EP 3 403 784 A1.

[0004] EP 3 403 784 A1 addresses the problem of simplifying the clamping of tools on machine tools without compromising the clamping strength and concentricity of the clamped tool. For this purpose, a clamping device comprises at least one clamping element held on the tool holder, which has a central opening for guiding a tool to be inserted into the tool holder. The clamping element is deformable by axial force, and the width of the opening can be changed by this deformation. The device also includes a clamping element mounted on the tool holder, which is axially displaceable between a clamping position and a release position. The clamping element can be axially actuated by moving the clamping element in the direction of the clamping position. The tool is clamped in the tool holder by a narrowing of the opening resulting from deformation of the clamping element.In the machining tool known from the prior art, this deformation is achieved by displacing the clamping element relative to the tool holder, thereby axially acting on the clamping element either by the clamping element itself or by a transmission element mechanically connected to it. A comparatively small axial stroke of the clamping element is sufficient to enable a high frictional torque transmission from the tool holder to the tool. The clamping element, for example, a flat conical clamping disc, particularly a star-shaped disc, has an annular form surrounding the central opening. Such a ring allows for a particularly uniform radial pressure to be exerted on the tool shank being clamped, resulting in high concentricity.The ring has an outer and an inner edge region, one of which can be axially actuated by sliding the clamping element towards the clamping position while supporting the other, in order to flatten the clamping element. During this flattening, the central recess of the ring narrows and conforms to a tool shank inserted through it, thereby reliably holding the shank.

[0005] A problem with such a machine tool is clamping milling cutters, drills, and similar tools with shanks of varying diameters. The inner diameter of the clamping discs is designed for a relatively small range of shank diameters and functions optimally only within this narrow range. For significantly smaller shank diameters, for example, reliable clamping is no longer guaranteed. In this case, sleeves are used to increase the shank diameter to the desired size. However, these sleeves have the disadvantage of impairing the tool's concentricity. Furthermore, clamping the tool requires additional steps: removing the appropriate sleeve, placing it on the end of the tool shank, and then clamping the shank, along with the sleeve, into the machine tool.Tools with larger shank diameters, on the other hand, cannot be clamped at all.

[0006] Furthermore, it is problematic that the tool undergoes a slight axial movement during the clamping process. This means that the axial alignment of the tool, and therefore the machining depth, is not easily reproducible. Disclosure of the invention

[0007] In contrast, the machining tool with the features of claim 1 makes it possible to clamp different tools, even with different shank diameters, very quickly and reliably for different machining operations, and in particular without the use of additional components, such as the aforementioned adapter sleeves. According to the invention, the clamping element is a clamping sleeve that can be detachably locked to the tool holder. Moving the clamping element in the direction of the clamping position reduces the width of the opening. It is particularly advantageous that the tools do not undergo any axial movement when clamped with such a clamping sleeve, and thus the depth stop of the tools is clearly defined.

[0008] These collets are each adapted to different shank diameters in terms of their width, i.e., their inner diameter. The collet is locked onto the tool holder and can be very quickly released from the tool holder at any time in order to lock a collet with a different width or inner diameter onto the tool holder.

[0009] Since locking and unlocking the collet on the tool holder is very quick, the machine tool can be quickly and easily converted to different shank diameters, and it is not necessary to adapt the shank diameters to the machine tool, as is known from the prior art.

[0010] This significantly simplifies the handling of the machine tool, while ensuring a secure hold of the tools even when changing different tools very quickly, as the clamping sleeves allow for particularly secure clamping of the tool.

[0011] According to a highly advantageous aspect of the invention, the clamping sleeve includes a depth-adjustable stop against which the shank end rests when clamped. This allows the machining depth of the tool to be preset very easily.

[0012] This depth-adjustable stop is advantageously implemented using a threaded pin, which is adjusted by turning, particularly when the collet is removed. The collet engages this threaded pin. This means that the threaded pin is adapted to the inner diameter of the collet, i.e., its width, and thus essentially corresponds to the diameter of the tool shank.

[0013] A particularly advantageous method, as mentioned earlier, is to secure the clamping element of the collet using a bayonet fitting. This bayonet fitting comprises a first cylindrical part, which is located on the tool holder, and a second cylindrical part, which can be attached to the first and in which the clamping element is detachably mounted. This second cylindrical part can be attached to the first by a simple 90° rotation, along with the collet itself. The collet is then secured, for example, in a circumferential groove in the second cylindrical part, utilizing its compressibility to be received, for instance, in a corresponding annular recess in the second cylindrical part. Brief description of the drawings

[0014] The invention is described below by way of example with reference to the drawing. The drawing shows: Fig. 1 an isometric view of a machining machine according to the invention in the unclamped state; Fig. 2 an isometric view of the in Fig. 1 shown machining machine in the clamped state; Fig. 3 a sectional view of the in Fig. 1 shown processing machine; Fig. 4 a sectional view of the in Fig. 2 shown processing machine; Fig. 5 a partially broken isometric detail view of a tool holder of the in Fig. 1 to 4 shown processing machine; Fig. 6 a partially broken isometric representation of the in Fig. 5 tool holder shown during the insertion of a tool using a collet; Fig. 7 an isometric representation of a collet and a tool inserted in it and Fig. 8 an isometric representation of the in Fig. 7 shown clamping sleeve from a different angle. Embodiments of the invention

[0015] A machining machine designated as a whole by 10, depicted in the Fig. 1 to 4, comprises a housing 11 in which a shaft 70 can be driven rotatably by an electric motor 72.

[0016] A clamping lever 20 with a handle 21 is rotatably arranged on the housing 11, which is assigned to an unclamped tool and in Fig. 1 is shown, in a second position, which is assigned to a clamped tool and in Fig. 2 is shown, which can be moved by a 90° rotation.

[0017] How the Fig. 3 and Fig. As can be seen from Figure 4, this 90° rotation inside the housing 11 causes a clamping element 40 to shift axially in the direction of a tool holder 60 and a tool 90 arranged therein at the tool-side end of the machine tool 10. The clamping element 40 has two supports 41, 42 extending perpendicular to the axial direction, which are rotationally fixed to each other. A spring 45 rests against one of the supports 42, which is tensioned when a tool 90 is relaxed ( Fig. 3) and is relaxed in the tensioned state of the tool at 90° ( Fig. 4) The clamping element 40 further comprises a sleeve-shaped end element 43, which encloses an internally conical sleeve 44. A clamping sleeve 50 rests against the conical surfaces and has a central opening adapted to the tool 90, into which the tool 90 is inserted. In the relaxed state of the tool 90, the internally conical sleeve 44 is displaced axially away from the tool-side opening 60 towards the electric motor 72, so that the clamping sleeve 50 releases the tool 90 due to lack of clamping. In this case, the spring assembly 45 is tensioned. In the clamped state of the tool 90, with the spring assembly 45 relaxed, the internally conical sleeve 44 is displaced towards the tool holder 60, its inclined conical surfaces sliding along the clamping sleeve 50 and thus clamping the tool 90. By moving the lever 20 using the handle 21 from the relaxed position ( Fig. 1 and Fig. 3) into the tense position ( Fig. 2 and Fig. 4) The tool 90 can be removed from the tool holder 60 and, for example, another tool can be inserted and clamped. In the clamped state, the tool 90 is set in rotation by means of an electric motor 72 via a shaft 70 and a hollow shaft 71, which is rotatably mounted within the clamping element 40.

[0018] Fig. Figure 5 shows an enlarged view of the tool holder 60. The tool holder 60 is designed as a bayonet fitting with a cylindrical first bayonet locking element 62 arranged non-rotatably on the housing 11, the inner diameter of which has a corresponding bayonet locking recess 63. The second bayonet locking element 64, which has a corresponding bayonet locking recess 66, is inserted into this first bayonet locking element 62. Fig. 7), is inserted by a 90° rotation and locked in the first bayonet locking element 62, which is rotationally fixed to the housing 11. The clamping sleeve 50 can be detachably fastened in the second bayonet locking element 64. This in the Fig. 7 and Fig. The clamping sleeve 50 shown in Figure 8 has slotted clamping elements 51 in a manner known per se, which are conically shaped on their outer circumference and form a sleeve-shaped opening 52 on their inner circumference. This opening 52 serves to receive the tool 90. The second bayonet locking element 64 has a knurled grip zone 65 on its front outer area for easier handling, which facilitates insertion and rotation and thus locking in the first bayonet locking element 62. As shown in particular in Fig.As shown in Figure 8, the tool 90, for example a drill or a milling cutter, is inserted on the side of the second bayonet locking element 64 facing away from the clamping element 50 and held there while the second bayonet locking element 64 is attached to the first bayonet locking element 62. The clamping element 50 is inserted into the opening of the first bayonet locking element 62 by means of the second bayonet locking element 64, whereby the cam 66 arranged on the outer circumference of the second bayonet locking element 64 engages in the cam 63 of the first bayonet locking element 62 and is locked by a rotational movement of 90°. Then, by actuating the lever 20 using the handle 21, the tool 90 is clamped by pushing the segments 51 inwards towards the axis of symmetry by moving the conical sleeve 44, thus clamping the tool 90 in the opening 52.

[0019] It should be emphasized that instead of the bayonet fitting described and illustrated here, a screw fitting (not shown) can also be provided for securing the tool 90 in the tool holder 60. In this case, a first screw fitting element is arranged on the housing 10, to which a second screw fitting element, which carries the clamping sleeve 50, can be attached and detached by screwing it in.

[0020] If a tool 90 with a tool shank of a different diameter is to be clamped, for which the collet 50 is unsuitable (e.g., because it has too large an inner diameter), the collet 50 is removed by rotating the second bayonet locking element 64 counterclockwise from the tool holder 60. The collet 50 is then removed from the second bayonet locking element 64 by compressing the segments 51. A collet 50 with a different inner diameter is then inserted into the second bayonet locking element 64 by compressing the segments 51, and this, together with the tool 90 of the different diameter, is secured in the tool holder 60, i.e., in the first bayonet locking element 62.In this way, adapter sleeves and the like can be omitted, which have a particularly negative impact on the concentricity of such a tool.

[0021] Instead, a clamping sleeve 50 adapted to the tool 90 is mounted, and the tool 90, together with this clamping sleeve 50, is mounted in the tool holder 60 by means of the two bayonet locking elements 62 and 64. The outer diameter remains unchanged, so that the outer conical surfaces of the segments 51 are unchanged, and the clamping process can be carried out as described above by sliding the conical sleeve 44.

[0022] It should also be emphasized that clamping the tool 90 by means of the clamping sleeve 50 does not lead to any movement of the tool 90 in the axial direction during the clamping process. Rather, the tool 90 does not shift in the axial direction, so that the depth setting of the tool 90 is retained during a subsequent machining operation.

[0023] To further modify and vary this depth setting, one embodiment provides for a threaded pin 80 to be arranged on the element 41. This pin can be actuated from outside the tool holder 60, thus allowing a change in the depth of the axial stop. Unscrewing this threaded pin 80 results in a shallower stop for the tool 90. Screwing the threaded pin 80 in results in a deeper stop for the tool 90. Only by using the clamping sleeve 50 is it ensured that no axial movement of the tool 90 occurs during the clamping process, thus enabling precise adjustment by means of a stop, such as that provided by the threaded pin 80. QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] EP 3 403 784 A1 [0003, 0004]

Claims

[1] Machine tool (10), in particular a router, with a shaft (70) which can be driven to rotate about an axis of rotation, a tool holder (60) which is coupled to the shaft (70) for driving purposes or is formed integrally with it, and a clamping device for detachably fastening a tool (90) in the tool holder (60), wherein the clamping device comprises: - at least one clamping element held on the tool holder, which has a central passage for guiding a tool (90) to be inserted into the tool holder (60), wherein the clamping element is deformable by axial force and the width of the passage can be changed by this deformation, and - a clamping element (40) mounted on the tool holder, which is axially displaceable between a clamping position and a release position, wherein the clamping element (40) can be axially actuated by displacing it in the direction of the clamping position, characterized by , that the clamping element is a clamping sleeve (50) which can be detachably locked on the tool holder (60) and which, by moving the clamping element (40) in the direction of the clamping position, experiences a reduction in the width of the passage (52). [2] Processing machine according to claim 1, characterized by , that the clamping element (50) can be releasably locked to the tool holder (60) by means of a bayonet fitting. [3] Processing machine according to claim 1, characterized by , that the clamping element (50) can be releasably locked to the tool holder by means of a screw closure. [4] Processing machine according to claim 1, characterized by, that the clamping sleeve (50) includes a depth-adjustable stop against which a shaft of the tool (90) rests when clamped. [5] Processing machine according to claim 4, characterized by , that the depth-adjustable stop is realized by a threaded pin (80). [6] Processing machine according to claim 2, characterized by , that the bayonet lock has a first bayonet lock element (62) which is arranged on the tool holder and a second bayonet lock element (64) which can be attached to the first bayonet lock element, in which the clamping sleeve (50) can be detachably attached.

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