Tool unit and switchable tool system for such a tool unit

Abstract

Tool unit for processing edges of workpieces and switchable tool system for such a tool unit. The tool unit comprises a tool head, a switching drive for it, a drive motor. The tool head has a first tool section with first cutters and a second tool section with second cutters. The second tool section can be moved back and forth between a passive position and an active position relative to the first tool section by means of the switching drive, the second cutters being pulled back in the passive position and protruding axially between the first cutters in the active position. The switching drive comprises at least one electromagnet and a control armature made of a magnetically attractable material arranged in the action area of the electromagnet. The electromagnet is positioned axially between the tool head and the drive motor and is fixed against rotation at a housing part of the drive motor. The control armature is firmly connected with the second tool section. A gap remains between the at least one electromagnet and the control armature not only in the passive position but also in the active position.

Description

Technical Field

[0001] The present invention relates to a tool unit for processing the edges of a workpiece and a switchable tool system for such a tool unit. Background Technology

[0002] A tool unit for processing the edges of a workpiece is known from EP 2 492 071 B1. This tool unit extends along a rotation axis and includes a tool head, a drive motor for rotating the tool head about the rotation axis, and a switching driver for switching the tool head between different switching states. The tool head has a first tool section with a set of first tools distributed on its periphery and a second tool section with a set of second tools distributed on its periphery. The second tools are positioned between the first tools when viewed in the peripheral direction. The second tool section can move back and forth between a passive position and an active position relative to the first tool section along the longitudinal axis by means of the switching driver, wherein in the passive position the second tools are axially pulled back relative to the first tools, and wherein in the active position the second tools protrude axially through the first tools.

[0003] The tool head is located at the axial end of the drive motor, while the switching drive is positioned at the opposite axial end. The switching drive can be designed electro-pneumatically, electro-hydraulically, and / or electromagnetically and acts on a moving cylinder. The movement of the moving cylinder is directed longitudinally through the drive spindle of the drive motor to the opposite movable tool section, determining the switching position of that tool section. Different milling profiles are used by switching between them. The selected drive configuration should improve the feasibility of the design and thus increase the flexibility of the multi-profile milling device.

[0004] However, this goal comes at the cost of high mechanical expenses associated with a complex and highly integrated structural design. The rotary drive and the switching drive must be coaxially inserted into and supported by each other. In addition to the resulting high construction and cost, wear occurs at the support points, leading to subsequent maintenance expenses. In the event of damage, the entire unit must be replaced or repaired. Standardized and therefore cost-effective drives cannot be used. Summary of the Invention

[0005] The objective of this invention is to significantly simplify the structural design of tool units of the type described at the beginning of this document and thereby reduce wear and tear and the resulting maintenance costs.

[0006] This task is solved by a tool unit for processing the edges of a workpiece, the tool unit extending along a rotation axis, the tool unit including a tool head extending along the rotation axis, a drive motor for rotatably driving the tool head about the rotation axis, and a switching driver for the tool head, wherein the tool head has a first tool section with a set of first tools distributed on its periphery and a second tool section with a set of second tools distributed on its periphery, wherein the second tools are positioned between the first tools when viewed in the peripheral direction, and wherein the second tool section can be switched between a passive position and an active position relative to the first tool section along the rotation axis by means of the switching driver. The second tool is pulled back axially relative to the first tool in a passive position, and in an active position the second tool protrudes axially through the first tool, wherein the switching driver includes at least one electromagnet and an operating armature made of a magnetically attractive material disposed within the operating region of the electromagnet, wherein the at least one electromagnet is axially positioned between the tool head and the drive motor and is torsionally fixed to the housing portion of the drive motor, wherein the operating armature is securely connected to the second tool section, and wherein a gap is maintained between the at least one electromagnet and the operating armature not only in the passive position but also in the active position.

[0007] Furthermore, the objective of this invention is to describe a switchable tool system for such a tool unit, which, with its simple structure and reliable function, can be used at a standardized drive motor.

[0008] This task is solved by a switchable tool system for a tool unit, wherein the tool unit includes a drive motor for rotatably driving a tool head about a rotation axis, wherein the switchable tool system includes a tool head and a switching driver for the tool head, wherein the tool head extends along the rotation axis and has a first tool section with a set of first tools distributed on its periphery and a second tool section with a set of second tools distributed on its periphery, wherein the second tools are positioned between the first tools when viewed in the peripheral direction, and wherein the second tool section can be switched relative to the first tool section in the longitudinal direction by means of the switching driver in a passive position and an active position. The tool moves back and forth between positions, wherein the second tool is pulled back axially relative to the first tool in a passive position, and wherein the second tool protrudes axially through the first tool in an active position, wherein the switching drive includes an operating armature made of a magnetically attractive material and at least one electromagnet acting on the operating armature, wherein the at least one electromagnet has a fixing device for torsionally fixing to a housing portion of the drive motor between the tool head and the drive motor in the axial position, wherein the operating armature is securely connected to the second tool section, and wherein the tool head has a fixing interface for fixing to the drive shaft of the drive motor.

[0009] According to the present invention, the switching drive includes at least one electromagnet and an operating armature made of a magnetically attractive material disposed in the operating region of the electromagnet. The at least one electromagnet is axially positioned between the tool head and the drive motor and is torsionally fixed to the housing portion of the drive motor. The operating armature is securely connected to a second tool section, wherein a gap is maintained between the at least one electromagnet and the operating armature not only in a passive position but also in an active position.

[0010] The corresponding switchable tool system includes the tool head and the switching driver. At least one electromagnet has a fixing device for torsionally securing it to the housing portion of the drive motor between the tool head and the drive motor in an axial position. The corresponding tool head has a fixing interface for securing it to the drive shaft of the drive motor.

[0011] In the design according to the invention, both the switchable tool head and the associated switching driver are located on the same side of the tool unit or drive motor, thus eliminating the need for expensive transmission devices. Although relative rotational movement is generated due to the electromagnet being fixed to the housing portion of the drive motor and the operating armature being fixed to the second tool section, it is unnecessary to provide a separate support structure between the two components, as the tool head's fixation at the drive shaft of the drive motor is sufficient. Therefore, the tool head is supported solely by the support structure of the drive shaft, while the electromagnet is mechanically and independently torsionally held at the motor. In particular, due to the gap between the electromagnet and the operating armature, there is a lack of direct contact between the two components, thus the arrangement is wear-free. The switchable tool system can be installed at any drive motor. Existing drive motors can be easily fitted with the switchable tool system according to the invention, as it does not require embedding within the drive motor.

[0012] The electromagnetic attraction is transmitted contactlessly through the gap. This gap must be designed to prevent friction, and therefore can be appropriately small. This allows for the application of a large magnetic force, ensuring reliable switching between different switching states or between active and passive positions. Furthermore, the achieved switching position can be reliably maintained.

[0013] It may be suitable to equip the control armature with permanent magnet characteristics when using a suitable hard magnetic material. Matching this, the electromagnet can operate with alternating polarities, resulting in attraction or repulsion between the permanent magnets. As a result, active and passive positions can be initiated and maintained solely by magnetic force. However, in a preferred extended design, the control armature is made of a soft magnetic material. Although this requires applying a magnetic attraction with only one corresponding switching direction, thus necessitating additional measures for switching in the opposite direction, the use of soft magnetic materials opens up a wide selection of materials that can be considered, including, for example, tool steel. This allows for a cost-effective and robust structural design.

[0014] In an advantageous embodiment, the second tool section is preloaded forward toward the active position by a switching actuator via a pressure spring element. The switching actuator is designed to, upon activation, draw the second tool section from the active position to the passive position against this preload force of the pressure spring element. This arrangement is achieved with minimal control overhead. The polarization direction of the electromagnet is not critical. Only two operating states are meaningful for the electromagnet: “energized” and “de-energized,” in which the electromagnet, in the energized state, pulls the second tool section back to the passive position and holds it there, and in the de-energized state, the pressure spring element pushes the second tool section forward into the active position and holds it there. Reliable and maintenance-free switching between the two switching states and reliable holding of the achieved switching state are achieved with minimal overhead.

[0015] Different possibilities are considered for the structural design. However, it is preferred to construct the compression spring element as a shaft spring arranged concentrically with the axis of rotation. High switching force and holding force can be achieved with very little axial construction space. The coaxial construction avoids tilting and warping.

[0016] The same description applies to a preferred embodiment in which the electromagnet is designed as a ring magnet, wherein the control armature and the ring magnet are correspondingly constructed in a ring, and wherein the ring magnet and the ring control armature are arranged concentrically with the axis of rotation. Attached Figure Description

[0017] Embodiments of the present invention will now be described in more detail with reference to the accompanying drawings. In the drawings: Figure 1 The working area of ​​a tool unit with a tool head, drive motor and switching driver, designed according to the present invention, is shown in the perspective view. Figure 2 The side view shows the button Figure 1 The tool unit, with a second tool section that is pulled back in its passive position; Figure 3 It shows the press Figure 2 The arrangement structure includes a second tool section located in the active position; and Figure 4 The cross-sectional view shows the switching state for milling two different edge profiles. Figures 1 to 3 A tool system that can be switched. Detailed Implementation

[0018] Figure 1 The working area of ​​the tool unit 1 designed according to the present invention is shown in the perspective view. The tool unit 1 is designed and configured for processing the workpiece 4. Figure 4 The edges 2 and 3 shown are preferably processed from wood and woody materials such as with or without coating (spanplatten). The tool unit 1 extends along the rotation axis 5 in a generally concentric configuration and includes a tool head 10, a drive motor 11 for rotatably driving the tool head about the rotation axis 5, and a switching driver 12 for the tool head 10, by means of which the tool head 10 can be brought into different switching states to produce different edges 2 and 3 with different edge profiles. Figure 4 ).

[0019] Therefore, the tool head 10 has a first tool section 6 with a set of first cutters 7 distributed around its periphery and a second tool section 8 with a set of second cutters 9 distributed around its periphery. The first cutters 7 and the second cutters 9 have different cutter profiles from each other. In the illustrated embodiment, the first cutter 7 has a recessed profile in the form of circular segments, while the second cutter 9 has a straight cutter profile that is curved relative to the axis of rotation 5, for example, at a 45° angle to the axis of rotation 5. However, other cutter profiles may be used for the first cutter 7 and the second cutter 9 within the scope of the invention.

[0020] Regardless, the second tool 9 is positioned between the first tool 7 when viewed along the peripheral direction, wherein the second tool section 8 can move back and forth between the passive position and the active position corresponding to the double arrow 22 relative to the first tool section 6 along the direction of the rotation axis 5 by means of the switching driver 12.

[0021] According to the invention, the switching driver 12 includes at least one electromagnet 14 and an operating armature 15 made of a magnetically attractive material disposed within the operating range of the electromagnet 14. The term "operating range" here refers to the fact that the electromagnet 14 acts on the operating armature 15 such that, during corresponding manipulation, the operating armature moves along the rotation axis 5 together with the second tool section 8, thus changing the switching position of the tool section. For this purpose, at least one electromagnet 14 is positioned axially, i.e., along the rotation axis 5, between the adjacent ends of the tool head 10 and the drive motor 11. Furthermore, at least one electromagnet 14 is provided with a fixing device 19, which is configured as a helical flange and, by means of the fixing device, torsionally secures the electromagnet 14 to the housing portion 13 of the drive motor 11. On the other hand, the operating armature 15 is torsionally connected to the second tool section 8 and therefore rotates with this second tool section or, as part of the tool unit 1, around the rotation axis 5 relative to the stationary electromagnet 14 or the stationary housing portion 13 of the drive motor 11.

[0022] Figure 2 , 3 The side view shows the buttons in different switching states. Figure 1 Tool unit 1, wherein the same reference numerals are used for the same features. Figure 2 The diagram illustrates a switching state in which the second tool section 8, together with its second cutter 9 and actuating armature 15, is pulled back relative to the axially fixed first tool section 6 in the direction of arrow 23 by means of a switching actuator 12 or an electromagnet 14. In this passive position, the second cutter 9 is pulled back axially relative to the first cutter 7 along the direction of the rotation axis 5, corresponding to arrow 23. Despite the maximum possible axial proximity, a gap 16 remains between the electromagnet 14 and the actuating armature 15, thus the two components are not in contact. The gap 16 is advantageously in the range of approximately 0.5 mm in the passive position shown, wherein a range of 0.2 mm to 1.0 mm is suitably considered.

[0023] In contrast, Figure 3 The diagram illustrates a switching state in which the second tool section 8, along with its second cutting tool 9 and the control armature 15, is in an active position. From the button... Figure 2 From the passive position, the structural unit thus undergoes an axial movement of the electromagnet 14 in the direction of the leading arrow 24. This selection of the travel distance ensures that the second tool 9, with its straight tool profile, moves in the direction of the leading arrow 24. Figure 3The active position protrudes axially along the direction of arrow 24, passing through the recessed first cutter 7. The required travel distance for this purpose is advantageously in the range of 2 to 4 mm, wherein the gap size of gap 16 is compared to... Figure 2 The passive position is increased by the magnitude of the travel distance. In any case, it is clear that a gap 16 with a clearance size > 0 is maintained between at least one electromagnet 14 and the control armature 15, whether in the passive position or the active position.

[0024] By pressing Figures 1 to 3 As shown in the diagram, tool unit 1 is basically composed of two sections: one consisting of a drive motor 11 and the other consisting of a switchable tool system, which includes the previously described tool head 10 and the switching driver 12, also described previously. The switchable tool system is generally positioned and fixed at only one axial end of the drive motor 11, so only the corresponding fixing interface is necessary, but intervention in the structural design of the drive motor 11 itself is not necessary. A commonly used, commercially available drive motor 11 can be selected or even added, wherein the switchable tool system with the tool head 10 and switching driver 12 can be installed at only one end of the drive motor 11.

[0025] To clarify other structural design details, Figure 4 The cross-sectional view shows the arrangement of... Figures 1 to 3 The switchable tool system described herein, for better understanding, illustrates two identical switchable tool systems that differ only in their switching states while sharing a consistent structural design. Thus, the tool head 10 includes a central body 26, with a first tool section 6 integrally constructed therein along with a first cutting tool 7 fixed thereto. This is to form a connection with the drive motor 11 (…). Figures 1 to 3 The drive shaft 18 has a fixed interface 21 with a tapered support 29 formed in the central body 26, which rests on the clamping cone of the drive shaft 18 in the installed state. Furthermore, a portion of the fixed interface 21 is a central clamping screw 27, which is loosely secured in the central body 26 by means of a retaining ring 28 and screwed into a threaded hole on the end side of the drive shaft 18 for installation. The tool head 10 is thus tensioned on the clamping cone of the drive shaft 18 by means of its central body 26, thus forming a centrally located, torsion-resistant unit consisting of the tool head 10 and the drive shaft 18. Further fixing or supporting of the tool head 10 is neither necessary nor provided. The tool head 10 is supported only by the drive shaft 18 and is also non-contact with respect to the electromagnet 14.

[0026] The second tool section 8, which is relatively fixed and movable axially along the first tool section 6, has a base 20, at which the second cutting tool 9 is fixed. Various elements made of magnetically attractive material can be arranged, fixed, or embedded in or at this base 20 to form the control armature 15. Permanent magnets may be involved here. In the preferred embodiment shown, the control armature 15 is generally made of a soft magnetic material, particularly tool steel, and is integrally constructed with the base 20. Corresponding to the control armature 15, a plurality of electromagnets 14 are arranged concentrically around the rotation axis 5. In the preferred embodiment shown, the electromagnets 14 are designed as toroidal magnets, and the control armature 15 is correspondingly designed as toroidal as well. The base with the shaped control armature 15 and the electromagnets 14, also designed as toroidal magnets, are concentrically positioned with respect to the rotation axis 5, resulting in a compact, tilt-free construction.

[0027] The central body 26 carries a surrounding pressure member 25 at its end facing the electrically driven motor 11, where a pressure spring element 17 is supported. The pressure spring element 17 can be a device consisting of multiple helical pressure springs, disc spring bundles, or the like distributed around its periphery, and in the illustrated embodiment, it is a shaft spring arranged concentrically with the rotation axis 5. The pressure spring element 17 is supported in the opposite direction toward the end face of the second tool section 8 and is provided with axial preload. Due to this axial preload, the second tool section 8 is preloaded forward and pressed into its active position by the switching drive 12, corresponding to arrow 24. Figure 4 In the upper part, the electromagnet 14 is passive, i.e., not energized, and therefore does not apply axial operating force to the operating armature 15. Therefore, the preload of the pressure spring element 17 causes the second tool section 8 to move in the direction of arrow 24 and occupy its active position there. Furthermore, this active position is maintained by the preload of the spring element 17, thus eliminating the need for separate locking. In any case, in this active position, the second tool 9 protrudes axially between the first tool 7 such that the second tool at workpiece 4 corresponds to the tool profile of the second tool 9, i.e., it is constructed here as a 45° bevel.

[0028] However, if a suitable supply voltage is applied to the electromagnet 14 and thus current is supplied to it, the electromagnet 14 exerts an axial attractive force on the operating armature 15 and therefore on the second tool section 8. The electromagnet 14 and the operating armature 15 are sized or designed such that this attractive force is sufficient to overcome the preload of the pressure spring element 17. This state is... Figure 4As shown in the lower part, the second tool section 8 is pulled back to the previously described passive position against the stop at the pressure member 25 and held there by the attraction of the electromagnet 14. In this pulled-back passive position, the straight second tool 9 is pulled back axially relative to the concave first tool 7, so that the tool head 10 produces an edge 3 with a corresponding rounded profile at the workpiece 4.

[0029] The switching between active and passive positions, and thus between different milling profiles of the edges 2, 3 to be produced, is accomplished solely through the interaction of the electromagnet 14, the actuating armature 15, and the preferred pressure spring element 17, depending on whether they are switched on or off.

Claims

1. A tool unit (1) for processing the edges (2, 3) of a workpiece (4), the tool unit extending along a rotation axis (5) and including a tool head (10) extending along the rotation axis (5), a drive motor (11) for rotating the tool head (10) about the rotation axis (5), and a switching driver (12) for the tool head (10), wherein, The tool head (10) has a first tool section (6) and a second tool section (8), the first tool section (6) having a set of first cutters (7) distributed on its periphery and the second tool section (8) having a set of second cutters (9) distributed on its periphery, wherein the second cutters (9) are positioned between the first cutters (7) when viewed in the periphery direction, wherein the second tool section (8) is movable relative to the first tool section (6) in the direction of the rotation axis (5) by means of a switching driver (12) between a passive position and an active position, wherein in the passive position the second cutters (9) are pulled back axially relative to the first cutters (7), and wherein in the active position the second cutters (9) protrude axially through the first cutters (7). The switching driver (12) is characterized by comprising at least one electromagnet (14) and an operating armature (15) made of a magnetically attractive material disposed in the operating area of ​​the electromagnet (14), wherein at least one electromagnet (14) is axially positioned between the tool head (10) and the drive motor (11) and is torsionally fixed at the housing portion (13) of the drive motor (11), wherein the operating armature (15) is securely connected to the second tool section (8), and wherein a gap (16) is provided between the at least one electromagnet (14) and the operating armature (15) not only in the passive position but also in the active position.

2. The tool unit according to claim 1, characterized in that, The control armature (15) is made of a soft magnetic material.

3. The tool unit according to claim 1, characterized in that, The second tool section (8) is preloaded forward toward the active position by means of the pressure spring element (17) and the switching driver (12) is designed to draw the second tool section (8) from the active position to the passive position against the preload force of the pressure spring element (17).

4. The tool unit according to claim 3, characterized in that, The pressure spring element (17) is configured as a shaft spring arranged concentrically with the rotation axis (5).

5. The tool unit according to claim 1, characterized in that, The electromagnet (14) is designed as a ring magnet, and the control armature (15) is constructed in a ring in correspondence with the ring magnet. The ring magnet and the ring control armature (15) are arranged concentrically with the rotation axis (5).

6. The tool unit according to claim 1, characterized in that, The tool head (10) is fixed only to the drive shaft (18) of the drive motor (11) and the tool head (10) and the electromagnet (14) are not in contact.

7. The tool unit according to claim 1, characterized in that, The second tool section (8) has a base (20) and the base (20) and the control armature (15) are integrally constructed of a material that can be magnetically attracted.

8. A switchable tool system for tool unit (1), wherein, The tool unit (1) includes a drive motor (11) for rotating a tool head (10) about a rotation axis (5). The switchable tool system includes a tool head (10) and a switching driver (12) for the tool head (10). The tool head (10) extends along the rotation axis (5) and has a first tool section (6) and a second tool section (8). The first tool section (6) has a set of first cutters (7) distributed on its periphery, and the second tool section (8) has a set of second cutters (9) distributed on its periphery. The second cutters (9) are positioned between the first cutters (7) when viewed in the peripheral direction. The second tool section (8) is movable relative to the first tool section (6) along the rotation axis (5) between a passive position and an active position by means of the switching driver (12). In the passive position, the second cutters (9) are axially pulled back relative to the first cutters (7), and in the active position, the second cutters (9) protrude axially through the first cutters (7). The switching driver (12) is characterized by comprising an operating armature (15) made of a magnetically attractive material and at least one electromagnet (14) acting on the operating armature (15), wherein at least one electromagnet (14) has a fixing device (19) for torsionally fixing between the tool head (10) and the drive motor (11) at a housing portion (13) of the drive motor (11) in an axial position, wherein the operating armature (15) is securely connected to a second tool section (8), and wherein the tool head (10) has a fixing interface (21) for fixing at a drive shaft (18) of the drive motor (11).

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