Tool exchange device

Abstract

The tool changer 200 functions to change tools 500 in the machine tool 100. The tool changer has a support structure 210 on which a lifting carriage 240 is guided along a vertical lifting direction Z3. A pivot arm 250 is attached to the lifting carriage 240 so as to be rotatable about a vertical pivot axis C3. A plurality of tool holders 221, 222, 223, 230 arranged vertically one above the other form a tool magazine 220. A tool gripper 260 is attached to the pivot arm 250. The tool gripper grips a tool 500. The tool is then moved between one of the tool holders and the tool spindle of the machine tool by a combination of lifting and pivoting movements of the pivot arm 250. Optionally, an additional arm 252 is pivotally attached to the pivot arm 250. The additional arm 252 can be used to replace the workpiece clamping means of the machine tool.

Description

Technical Field

[0001] The present invention relates to a tool changer for a machine tool, a machine tool provided with the tool changer, and the use of such a tool changer. The machine tool can be, in particular, a gear hobbing machine that performs gear generation machining. The tool to be exchanged can be, in particular, a gear skiving tool.

Background Art

[0002] In machine tools, it is often necessary to replace one tool with another, for example, to resharpen a worn tool. This also applies in particular to gear hobbing machines. For example, gear skiving tools have a service life and must therefore be replaced regularly. In order to reduce the labor and time required for tool change, automatic tool changers have been proposed in the current state of the art.

[0003] For example, Patent Document 1 discloses a tool changer in a hobbing machine. During tool change, a tool in the form of a hob cutter is removed from the tool head of the hobbing machine and lifted by a suspension device. The suspension device is transferred to an intermediate position by a horizontal transfer rail, where it can rotate about a vertical axis to the removal position to remove the hob cutter. Due to its design, this tool changer is suitable only for machines in which the tool rotation axis is horizontal and only for tools attached to both sides of the tool head. The tool changer is not particularly suitable for gear skiving tools. Also, this tool changer takes up a lot of space.

[0004] Patent Document 2 discloses a tool changer equipped with a gripper attached to a carriage unit having three carriages. The milling tool is vertically suspended in a circulating magazine. The rotation in the circulating magazine occurs in a horizontal plane. The milling tool can be reciprocally transferred between the circulating magazine and the machining head by the tool changer. Due to its design, this tool changer is also only suitable for tools attached to both sides of the tool head, and thus is not suitable for gear skiving tools. In addition, this tool changer also takes up a lot of space.

[0005] Patent Document 3 discloses a tool changer that reciprocally transfers a gear skiving tool between a circulating magazine and a machining head by a horizontal carriage. Here, the circulation of the circulating magazine occurs in a vertical plane. This tool changer also requires a relatively large space.

[0006] Patent Document 4 discloses a tool changer that can also be used for the exchange of gear skiving tools. The tools are stored in a drum-shaped tool magazine. The tool changer has a double arm that can pivot about a horizontal axis. Gripping sections are formed at the free ends of the double arm respectively. The double arm grips both the machining tool clamped on the tool spindle by the gripping section and the tool discharged from the tool magazine, and exchanges these two tools with each other. This tool changer also takes up a relatively large space.

[0007] Patent Document 5 discloses a tool magazine in which a plurality of bending tools are stored in vertically arranged tool holders. An articulated arm robot removes the tools from the magazine and transfers them to a bending machine. The use in a gear hobbing machine is not disclosed.

[0008] Patent Document 6 discloses a tool changer having a vertically movable and rotatable column to which a double gripper is attached. The tool changer transfers tools between a tool spindle and a chain magazine on which the tools are suspended. The tool changer has a complex cam mechanism that provides vertical and rotational movements. The design of the tool changer is relatively complex. Here too, its use in a milling machine is not disclosed.

Prior Art Documents

Patent Documents

[0009]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Patent Document 5

Patent Document 6

Summary of the Invention

[0010] An object of the present invention is to disclose a tool changer that can be configured to be particularly space-saving due to its configuration.

[0011] This object is achieved by the tool changer according to claim 1. Further embodiments are defined in the dependent claims.

[0012] A tool changer for exchanging tools in a machine tool, particularly a milling machine, is disclosed. The tool changer includes a support structure, and a lifting carriage guided on the support structure along a lifting direction extending vertically in a space. A pivot arm pivotally attached to the lifting carriage so as to be rotatable about a pivot axis extending vertically within the space, A tool gripper attached to the pivot arm and configured to grip a tool, A tool magazine having a plurality of tool holders arranged vertically one above the other, comprising The tool changer is configured to selectively move the tool gripped by the tool gripper between one of the tool holders and the tool spindle of the machine tool or between two different tool holders of the tool magazine by a combination of the lifting and pivoting movements of the pivot arm.

[0013] Since the tool magazine is formed by several tool holders arranged vertically one above the other, the space requirements for the tool magazine are very small. Such a tool magazine can be loaded and unloaded very easily. For this purpose, the present invention proposes a vertically movable lifting carriage to which a horizontally pivotable pivot arm provided with a tool gripper is pivotally attached. Such a configuration can be implemented simply and inexpensively and also requires very little space. Generally, as a result, it becomes a very compact tool changer that can be easily incorporated directly into the machine tool by connecting the support structure to the machine bed of the machine tool.

[0014] In particular, the support structure can comprise a vertical column configured such that its lower end is attached to the machine bed of the machine tool. Also, the lifting carriage is guided along the lifting direction on the column. The tool holders are preferably also attached to this column. However, in an alternative embodiment, it is also conceivable to attach the tool holders to another member of the support structure.

[0015] To enable particularly simple loading of the tool magazine, one of the tool holders of the tool magazine can be movably attached to the support structure, in particular displaceable along the horizontal loading direction and / or pivotable about a vertical loading pivot axis. In particular, the tool changing device can comprise an outer wall that separates the internal space of the tool changing device from the external space. Further, the outer wall can comprise a tool loading opening for exchanging tools between the internal space and the external space. Thus, it is particularly advantageous if the movable tool holder is movable through the tool loading opening to be accessible from the external space. The remaining tool holders can be fixedly connected to the support structure.

[0016] The tool changing device can comprise a tool loading door configured to selectively open and close the tool loading opening. The tool loading door can comprise a status indicator that notifies the control device of the open state (open or closed) of the tool loading opening. The control device can be configured to prevent the operation inside the tool changing device as long as the tool loading opening is open and / or prevent the opening of the tool loading door as long as an operation is being performed inside the tool changing device.

[0017] In a preferred embodiment, the movable tool changing device is implemented as follows. The tool changing device has a loading linear guide and a loading carriage guided by the loading linear guide so as to be displaceable along the horizontal loading direction. Further, the movable tool holder is attached onto the loading carriage so as to be pivotable about a vertical loading pivot axis. By enabling the combination of linear displacement and pivoting of the movable tool holder in this way, particularly good accessibility of this tool holder is achieved with minimal space requirements.

[0018] The tool changer preferably further includes a partition configured to separate the internal space of the tool changer from the machining space of the machine tool. The partition has a partition opening, and the tool changer includes a partition door configured to selectively open and close the partition opening. For this purpose, the partition door can include a corresponding drive unit, for example, a pneumatic drive unit. The partition opening has a sufficient height such that a pivot arm to which a tool gripper is attached can move through the open partition opening at at least one position of the lifting carriage, preferably within a certain range of positions of the lifting carriage. Also, the partition opening preferably has a sufficient height such that the lifting carriage can move along the lifting direction by a certain amount when the pivot arm extends through the partition opening. In this way, tool changing, and the replacement of optional clamping means and / or workpieces, which will be described in more detail later, are facilitated.

[0019] The tool changer can further include a reading station, which is arranged such that a tool held by a tool gripper can be moved to the reading station by a combination of the lifting and swiveling movements of the pivot arm to read a machine-readable data carrier on the tool. For example, the data carrier can be an RFID transponder. Accordingly, the reading station can be an RFID station having an RFID transceiver. In other embodiments, the data carrier can be an optical data carrier, such as a barcode or a QR code (registered trademark), in which case the reading station can be configured to optically read such an optical data carrier. For this purpose, the reading station can include a corresponding reading device including an optical sensor, such as a camera, and optionally a light source, such as an LED light source. Magnetic data carriers or tactually readable data carriers are also conceivable.

[0020] To avoid damage to the reading station, the reading station can have a spring-loaded design. For this purpose, the reading station can include a base, the above-described reading device, and a spring member disposed between the base and the reading device, and the reading device can move vertically downward with respect to the base against the restoring force provided by the spring member. Thereby, when a tool is placed on the reading station, damage to the reading device or the corresponding data carrier is prevented. This is particularly advantageous when tools of different lengths are used and the lengths of the respective tools are not known in advance. By spring-loading the reading station, the lifting carriage can always move to the same position for reading the tool regardless of the length of the tool. Thus, the difference in the lengths of the tools is compensated for by the spring member.

[0021] The tool changer can further include a tool cleaner. Preferably, the tool held by the tool gripper can be arranged to be movable toward the tool cleaner by a combination of the lifting and pivoting movements of the pivot arm to clean the tool support portion of the tool. In particular, the tool cleaner can be arranged on a support structure, particularly above the tool holder. When the support structure is formed in a columnar shape, the tool cleaner can be arranged at the upper end of the column.

[0022] To reduce non-productive idle time, the tool gripper can be configured as a plurality of grippers having at least two pairs of gripper jaws so as to be able to grip two or more tools.

[0023] The tool gripper can be firmly or movably attached to the pivot arm. In particular, the tool gripper can be attached to the pivot arm so as to be pivotable, for example, pivotable about a vertical or horizontal gripper pivot axis and / or displaceable, particularly linearly displaceable along a horizontal gripper displacement direction.

[0024] Objects other than tools can also be gripped by the tool gripper in order to perform additional functions with these objects. For example, the tool changer can include a taper cleaner configured to be gripped by the tool gripper. The taper cleaner can be moved toward the tool spindle by a combination of the lifting and swiveling movements of the pivot arm in order to clean its taper receptacle. Also, the tool changer can include a measuring probe, which can be configured, for example, to measure the radial and axial runout of the work clamping means of the machine tool. Further, the measuring probe can be configured to be grippable by the tool gripper in order to be moved to the measuring position by a combination of the lifting and swiveling movements of the pivot arm. The measuring probe can be continuously held at the measuring position by the tool gripper or, at the measuring position, can be received by another component of the machine tool, for example, can be clamped onto the tool spindle.

[0025] The tool changer can be configured to exchange not only tools but also workpieces. For this purpose, the tool changer can further include a workpiece gripper attached to the pivot arm. The workpiece gripper can move in the same manner as the tool gripper by a combination of the lifting and swiveling movements of the pivot arm. Also, the workpiece gripper can be configured to pick up the workpiece from the workpiece rest and transfer it to the work spindle of the machine tool.

[0026] To provide a combined lifting and pivoting movement of the pivot arm, the tool changer can include a lifting carriage drive for driving the lifting carriage to perform a lifting movement along the lifting direction, and a pivot drive for driving the pivot arm to perform a pivoting movement with respect to the lifting carriage about the pivot axis. Further, the tool changer can include a control device configured to control the lifting carriage drive, the pivot drive, and the gripper, and optionally other components of the tool changer. The control device can be an integral part of the machine control unit of the machine tool, but it is also conceivable to provide an independent control device that controls only the components of the tool changer and communicates with the actual machine control unit. The control device can preferably include a programmed control computer. This control computer can interact with a suitable NC axis module for each individual drive unit.

[0027] In particular, the control device can be configured to control at least one of the following operations: a) Gripping a tool by the tool gripper, b) Moving the tool gripped by the tool gripper between one of the tool holders and the tool spindle of the machine tool by a combination of the lifting and pivoting movements of the pivot arm, c) Moving the tool gripped by the tool gripper between two different tool holders of the tool magazine by a combination of the lifting and pivoting movements of the pivot arm, d) Opening and closing the partition door, e) Moving the tool gripped by the tool gripper to the reading station by a combination of the lifting and pivoting movements of the pivot arm and reading the data carrier on the gripped tool, f) Moving the tool gripped by the tool gripper to the tool cleaner by a combination of the lifting and pivoting movements of the pivot arm and cleaning the tool support part of the gripped tool by the tool cleaner, g) Moving the tool gripper with respect to the pivot arm, h) moving the taper cleaner gripped by the tool gripper to the tool spindle by a combination of the lifting and swiveling movements of the pivot arm; j) moving the measuring probe gripped by the tool gripper to the measuring position by a combination of the lifting and swiveling movements of the pivot arm; k) gripping the workpiece by the workpiece gripper and moving the workpiece gripped by the workpiece gripper between the workpiece rest and the workpiece spindle of the machine tool by a combination of the lifting and swiveling movements of the pivot arm.

[0028] In this regard, the present invention also discloses a method of operating a tool changer of the above-described type, which method includes performing at least one of the operations a) to k) described above.

[0029] In a preferred embodiment, the tool changer can be used not only for exchanging tools but also for exchanging the workpiece clamping means. For this purpose, the tool changer has an auxiliary arm attached to the pivot arm so that the auxiliary pivot axis of the auxiliary arm and the pivot axis of the pivot arm are parallel and spaced apart from each other and the auxiliary arm is pivotable about a vertically extending auxiliary pivot axis. The auxiliary arm is preferably releasably lockable to the pivot arm in a stationary position to prevent the pivoting movement of the auxiliary arm about the auxiliary pivot axis. The auxiliary arm is configured such that the workpiece clamping means of the machine tool can be attached thereto.

[0030] For this purpose, the auxiliary arm can, for example, have a receptacle for the clamping means holder. This receptacle can be configured, for example, as a bayonet connection between the auxiliary arm and the clamping means holder. For this purpose, the receptacle can be annular with an optional recess for bayonet connection on its inner circumference. Thus, the workpiece changing device can also comprise a clamping means holder configured to be removably connected to the auxiliary arm and the workpiece clamping means such that the workpiece clamping means can be attached to the auxiliary arm via the clamping means holder. In particular, the workpiece clamping means can be suspended and attached to the auxiliary arm. Thereby, since it does not receive loads due to torsional force or shear force, it becomes possible to use a particularly simple and lightweight clamping means holder.

[0031] The auxiliary arm makes it particularly easy to replace the clamping means for the workpiece. External auxiliary means such as a site crane, a mobile crane trolley, a special setup trolley with corresponding additional functions, etc. may not be required. Thereby, the cost can be significantly reduced, and the space requirements for external auxiliary means are eliminated.

[0032] In order to detect the vertical load on the auxiliary arm, a force transducer can be arranged on the auxiliary arm. For example, the receptacle for the clamping means holder can be connected to the auxiliary arm via the force transducer. In this way, the overload of the pivot arm and auxiliary arm system can be detected.

[0033] The present invention also discloses the use of a tool changing device of the above-described type for changing the workpiece clamping means in a machine tool. The corresponding method includes at least one, preferably all, of the following steps, and these steps are not necessarily executed in the order shown: Executing a combination of the lifting and swiveling movements of the pivot arm and swiveling the auxiliary arm relative to the pivot arm to bring the auxiliary arm to a position where it can be connected to the workpiece clamping means via the clamping means holder. Connecting the clamp means holder to the auxiliary arm and the work clamping means, By the lifting movement of the lifting carriage, lifting and lowering the work clamping means attached to the auxiliary arm via the clamp means holder, By pivoting the pivot arm, pivoting the work clamping means attached to the clamp means holder into the external space of the machine tool, By the lifting movement of the lifting carriage, placing the work clamping means attached to the clamp means holder on the clamp means rest.

[0034] The present invention further relates to a machine tool equipped with a tool changing device of the type described above. The machine tool can be a gear cutting machine, particularly a gear cutting machine for generating gears. The machine tool includes a machine bed and a tool spindle. The tool spindle is used to drive a tool that rotates about a tool axis. The tool spindle is preferably pivotally arranged with respect to the machine bed in the machine tool so that the tool axis can be brought to a position extending vertically in space in order to perform tool changing. Also, the tool changing device is arranged on the machine bed such that a tool gripped by a tool gripper can be moved from one of the tool holders of the tool magazine to the tool spindle by a combination of the lifting and pivoting movements of the pivot arm.

[0035] In particular, the tool spindle can be moved relative to the machine bed along at least one movement direction so that the tool spindle can move to a position where it can clamp a tool gripped on the tool gripper onto the tool spindle, or to a retracted position where the tool spindle with the tool clamped is located outside the collision contour of the pivoting movement of the pivot arm. This movement direction extends transversely to the lifting direction of the lifting carriage. This movement direction is preferably horizontal. Further, the tool spindle may be movable along a direction parallel to the lifting direction of the lifting carriage.

[0036] The machine tool preferably further comprises a work spindle having work clamping means. The work spindle drives the work clamping means to rotate about the work axis. The work axis is preferably vertical in space. When the machine tool is a gear hobbing machine for generating gear teeth, the machine tool has a mechanical control unit that establishes a gear connection between the rotational movement of the tool spindle and the rotational movement of the work spindle, that is, couples these movements such that the corresponding rotational speeds of each other have a predetermined fixed ratio and a predetermined phase relationship.

[0037] The work spindle is preferably arranged on the machine bed such that the work clamping means can be attached to the auxiliary arm when the auxiliary arm moves out of the stationary position relative to the pivot arm. For this purpose, the work spindle preferably moves along at least one direction relative to the machine bed to bring the tool spindle to a position where a receptacle on the auxiliary arm is arranged vertically above the work clamping means located on the work spindle, and this direction extends laterally with respect to the lifting direction of the lifting carriage. This direction also preferably extends horizontally. This direction is preferably orthogonal to the horizontal direction along which the horizontally moving tool spindle travels.

[0038] Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. The drawings merely serve for explanation and should not be construed as limiting. The drawings are each shown in a schematic perspective view.

Brief Description of the Drawings

[0039]

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Embodiments for Carrying Out the Invention

[0040] [Definitions] Gear hobbing machine: A machine configured to generate or machine the teeth of a gear on a workpiece, particularly internal or external teeth in a gear. For example, it can be a precision machining machine used for machining a pre-toothed workpiece, particularly a hard finishing machine used for machining a pre-toothed workpiece according to a hardening process.

[0041] Gear generation machining: A type of gear machining in which a tool rolls on a workpiece to bring about a cutting operation. Various gear generation machining processes are known, and they are distinguished between processes using geometrically undefined cutting edges such as generation gear grinding or gear honing, and processes using geometrically defined cutting edges such as gear hobbing, gear skiving, gear shaving, or gear shaping.

[0042] Gear skiving or hob peeling: The gear skiving process is a continuous chip removal process in which an axisymmetric periodic structure is generated using a gear-shaped tool. A gear skiving tool (“skiving wheel”) has a number of cutting edges on its face. The tool and the workpiece are attached to rotating spindles. The rotational axes of the tool and the workpiece are arranged obliquely to each other. A typical rolling motion is achieved by combining the rotational motion of the tool about the rotational axis and the rotational motion of the workpiece. This rolling motion, together with the axial feed motion of the tool or the workpiece along the workpiece axis, causes the cutting operation during gear skiving. By this process, both external gears and internal gears can be machined.

[0043] Combination of lifting and swiveling motions of a pivot arm: This term represents that both the lifting motion (using a lifting carriage) and the swiveling motion of a pivot arm occur. These motions can occur simultaneously, but they do not necessarily have to. These motions can also be performed in sequence, repeating the lifting motion and the swiveling motion alternately several times as necessary.

[0044] [Machine tool equipped with a tool changer according to the first embodiment] FIG. 1 shows an example of a machine tool 100 having a tool changer 200 according to the first embodiment of the present invention.

[0045] The illustrated machine tool 100 is a milling machine particularly suitable for gear skiving processes. However, it is also possible to perform other types of machining, particularly other gear generation processes, using such a machine. In FIG. 1, the machine is shown only very schematically. For details of possible specific embodiments of the machine, reference is made to Swiss Patent No. 715794, the entire disclosure of which is incorporated herein by reference. In the following, only some essential features of the machine will be described to facilitate understanding of the operation of the tool changing device 200 described below.

[0046] The machine has a machine bed 110. The machine bed 110 has a generally L-shaped configuration in side view, having a horizontal section 111 and a vertical section 112. The Y carriage 120 is disposed on the horizontal section 111. The Y carriage 120 is displaceable along the Y direction relative to the machine bed 110 by a drive unit (not shown). The Y direction extends horizontally within the space.

[0047] The Y carriage 120 holds a work spindle 130 provided with work clamping means 140, and a work (not shown) can be clamped onto the work spindle 130 by the work spindle 130. Thus, the Y carriage 120 functions as a work carrier.

[0048] The clamping means 140 is driven by the work spindle 130 and is attached to the work spindle 130 so as to be rotatable about a work axis, a so-called C axis. The C axis extends vertically within the space, i.e., along the direction of gravity. Both the C axis and the Y direction extend in the central plane of the machine. The central plane includes the C axis regardless of the position of the Y carriage 120 along the Y direction.

[0049] The Z carriage 150 is disposed on the vertical section 112 of the machine bed 110. The Z carriage is displaceable along the Z direction relative to the machine bed 110 by a drive unit (not shown). Here, the Z direction extends vertically within the space, parallel to the C axis and perpendicular to the Y direction.

[0050] On the Z carriage 150, an X carriage 160 that holds a tool spindle 170 and forms a tool carrier is arranged. The X carriage 160 is displaceable along the X direction with respect to the Z carriage 150 by a driving unit (not shown). Here, the X direction extends horizontally in the space, perpendicular to the Z direction and the Y direction, and thus perpendicular to the central plane. Both the Z carriage 150 and the X carriage 160 form a cross carriage, enabling the tool spindle 170 attached thereto to be displaced along the mutually perpendicular Z direction and X direction.

[0051] The tool spindle 170 drives a tool 500 attached thereto, for example, a gear skiving tool, and rotates it about a tool axis, a so-called B axis. For this purpose, the tool 500 is provided with a tool support portion that can have a hollow taper shank conforming to, for example, DIN 69893-1:2011-04 or DIN 69893-6:2003-05 for connection to the tool spindle. By the tool support portion, the tool 500 is clamped to the clamping means of the tool spindle 170.

[0052] The tool spindle 170 can be pivoted about a so-called A axis with respect to the X carriage 160 by a driving unit (not shown). The A axis is perpendicular to the B axis, parallel to the X axis, and perpendicular to the central plane. The A axis intersects the B axis. The pivoting plane in which the B axis pivots is parallel to the central plane.

[0053] A control device 180 is used to control the machine. In particular, the control device 180 controls a pivot drive unit around the axis A, spindle drive units for the tool axis B and the work axis C, and drive units for linear displacement along the X, Y, and Z directions. The control device 180 interacts with a control panel (not shown), and the control panel enables an operator to input control commands to the control device 180 and receive status messages.

[0054] For the movement of the Y carriage 120, the Z carriage 150, and the X carriage 160, and for the possible configurations of the drive and guide for the swiveling movement of the tool spindle 170 about the A axis, and for further structural details, reference is made to Swiss Patent No. 715794.

[0055] [Machining of the workpiece] To machine a workpiece using the machine according to FIG. 1, the Y carriage 120 is first moved to the workpiece exchange position in the Y direction. At this position, the latest finished workpiece is removed from the clamping means 140 manually or by a workpiece loading unit (not shown), and the blank workpiece to be machined is placed on and clamped by the clamping means 140. Thereafter, the Y carriage 120 moves along the Y direction to the machining position. When the blank workpiece is a pre-toothed workpiece, in order to determine the angular position of the tooth grooves of the blank workpiece using an engagement device (not shown), these tooth grooves are measured. Thereafter, the Z carriage 150 and the X carriage 160 are brought to the position where the tool 500 engages with the blank workpiece. At the same time, the tool spindle 170 is at an angular position about the A axis corresponding in particular to the twist angle of the workpiece. Here, the gear generation machining of the blank workpiece is performed in a normal manner. The tool 500 and the workpiece rotate at a prescribed rotational speed ratio. This forced connection is performed electronically by the control device 180. By the movement of the Z carriage 150, an axial feed along the workpiece axis is realized. By the movement of the X carriage and / or the Y carriage, the radial feed of the tool with respect to the workpiece axis can be changed. These movements are also controlled by the control device 180.

[0056] After a certain period of time, the cutting edge of the tool 500 wears to such an extent that the tool 500 must be replaced with a newly sharpened tool. The tool changer 200 described below is used for this purpose.

[0057] [Structure of the tool changer] [Tool magazine and tool loading station] The tool changer 200 of the machine 100 is shown alone in FIG. 2. The tool changer 200 has a support structure in the form of a vertical column 210 on which a plurality (here, three) of tool holders 221, 222, 223 are firmly arranged vertically. These fixed tool holders are hereinafter also referred to as "tool storage locations".

[0058] A further tool holder 230 is arranged below the lowermost fixed tool holder 223. This tool holder is movable in the horizontal direction with respect to the column 210, and in particular, is displaceable in the horizontal direction and rotatable about the vertical axis. The movable tool holder 230 functions to transfer tools between the inside and outside of the tool changer 200. The movable tool holder 230 is hereinafter also referred to as "tool loading station". The structure and function of the tool loading station will be described in more detail below with respect to FIGS. 7, 8, and 9A - 9D. Of course, the tool loading station can also be arranged at a position between the fixed tool holders so as to be at an ergonomic height for the operator.

[0059] Each of the tool holders 221, 222, 223, and 230 is configured to receive its respective tool 500. For this purpose, the tool holder has a shape complementary to the shape of the corresponding part of the tool. In this example, the tool holder is formed as a horizontal plate having a substantially semi-circular recess. This recess receives the reduced-diameter portion of the cylindrical tool. The collar of the tool support portion arranged above the larger diameter forms an annular support surface, whereby the tool is placed at rest in the area of the plate surrounding the recess. However, of course, other forms of tool holders are also conceivable.

[0060] Position sensors (not shown) in each of the tool holders 221, 222, 223, and 230 detect whether the tool 500 is disposed within the associated tool holder and notify the control device 180 of the same. The position sensor can be, for example, a simple mechanical switch actuated by a tool disposed within the associated tool holder. In the example of FIG. 2, the three fixed tool holders (tool storage locations) are each occupied by a tool 500, while the movable tool holder 230 (tool loading station) is unoccupied.

[0061] The tool holders 221, 222, 223, and 230 form a tool magazine 220 that holds a limited number of tools (here, a maximum of four tools) directly available in the machine 100.

[0062] [Partition] The partition 300 separates the tool changer 200 from the machining space of the machine tool 100. The partition 300 separates the interior of the tool changer 200 from the machining space of the machine tool 100 and thereby functions to protect the interior of the tool changer 200 from contamination by coolant and / or chips.

[0063] The partition 300 includes a partition wall 310 extending in the vertical direction. Adjacent to the lower end of the partition wall 310, there is an apron 340 protruding downward at an angle into the machining space of the machine tool 100, whereby coolant and / or chips can be discharged toward a chip conveyor (not shown) located below the machine bed 110. A partition opening 320 is formed in the vertical partition 310 and can be closed by a vertically slidable partition door 330. An actuator (not shown), for example, a pneumatic actuator known in the prior art, is used to effect the opening and closing operation. This drive is controlled by the control device 180.

[0064] The safety switch transmits a signal to the control device 180 regarding the state (open / closed) of the partition door 330, preventing the workpiece from being machined in the machine tool when the partition door 330 is open, and also preventing the swing arm 250 from moving through the partition opening 320 when the partition door 330 is closed.

[0065] [Outer wall with tool loading door] On the side facing the partition 300 of the tool magazine, the outer wall 400 is arranged so as to laterally separate the tool changer 200 from the external space. A tool loading opening 410 is formed in the outer wall 400, and this tool loading opening 410 can be closed by a tool loading door 420. In this example, the tool loading door 420 is rotatably mounted on the outer wall 400. In this example, the tool loading door 420 is manually opened and closed.

[0066] The outer wall 400 forms a lateral boundary between the machine 100 and the external space. The tool loading door 420 functions to prevent the operator of the machine 100 from being injured by the movable part of the tool changer 200. In particular, the tool loading door 420 can be provided with a status indicator that notifies the control device 180 of the state (open or closed) of the tool loading door 420. The control device 180 prevents the movable part of the workpiece changer from performing any operation as long as the tool loading door 420 is open, and in other cases, prevents the opening of the tool loading door 420.

[0067] [RFID station] The RFID station 600 is located in the area between the partition 300 and the outer wall 400 and is protected from coolant and chips. The structure and function of the RFID station 600 will be described in more detail below in relation to FIGS. 10 and 11.

[0068] [Pivot arm on the Z3 carriage] In FIG. 3, the tool changer 200 is shown without the partition 300. In this figure, further components of the tool changer that were hidden by the partition wall 310 in FIG. 2 can be seen.

[0069] In particular, an elevating carriage 240 that is vertically displaceably guided on a support column 210 can be seen. This elevating carriage will hereinafter also be referred to as the "Z3 carriage". The Z3 carriage 240 holds a pivot arm 250, and the pivot arm 250 is pivotable about a vertical axis via a pivot bearing 251. This axis is also referred to herein as the "C3 axis". The C3 axis extends at a distance from the support column 210 in a region located between the support column 210 and the machining space of the machine 100 or between the support column 210 and the partition 300.

[0070] A tool gripper 260, shown only schematically, is attached to the free end of the pivot arm 250. The tool gripper enables gripping a tool 500 disposed in one of the tool holders 221, 222, 223, 230 and moving it to another location. For this purpose, the tool gripper comprises two gripper jaws (not individually shown in FIG. 3), and the gripper jaws are movable towards each other, whereby the tool gripper grips the tool support portion of the tool 500 at its collar.

[0071] Below the pivot arm 250 there is an auxiliary arm 252, the function of which will be described in more detail below with reference to FIGS. 19 to 22. The auxiliary arm 252 does not operate during normal operation and is locked in the rest position of the pivot arm 250.

[0072] [Operation of the tool changer] Here, with reference to FIGS. 1 to 13, the operation of the tool changer 200 will be described in more detail.

[0073] [Intermediate position (FIG. 1)] In FIG. 1, the Z3 carriage 240 and the pivot arm 250 are in an intermediate position that can be normally obtained during the operation of the tool changer. At this position, the pivot arm 250 and the gripper 260 are completely contained within the tool changer separated by the partition 300 and the outer wall 400. At this position, the partition door 330 can be closed to protect the tool changer from contamination during the machining of the workpiece in the machine tool 100.

[0074] [Taking out the tool from the tool magazine (FIGS. 2 to 4)] To remove the tool from one of the tool holders 221, 222, 223, or 230, the tool gripper 260 moves toward the tool 500 by the pivot arm 250 and the Z3 carriage 240. This is shown for the lowermost fixed tool holder in FIGS. 2 to 4. The tool gripper 260 grips the tool. Then, the pivot arm 250 slightly lifts and pivots outward toward the partition wall 310 until the tool is directly above the RFID station 600. At this position, the pivot arm 250, together with the tool gripper 260 and the tool held therein, can move up and down along the Z3 direction without colliding by the movement of the Z3 carriage 240. During that time, the partition door 330 can remain closed.

[0075] Next, the tool can be placed in another tool holder and moved to the RFID station 600 or to the tool spindle 170 by appropriate movement of the Z3 carriage 240 and the pivot arm 250.

[0076] [Transfer to the tool spindle (FIGS. 5 and 6)] To move the tool 500 to the tool spindle 170, as described above, the tool is removed from one of the tool holders and the Z3 carriage 240 is used to move it to a position just behind the partition door 330. The partition door 330 is opened and the pivot arm 250 pivots through the partition opening 320 into the machining space of the machine tool 100 until the tool 500 held on the pivot arm 250 is positioned directly below the tool spindle 170. For this purpose, the tool spindle 170 is brought to an appropriate position in advance by the Z carriage 150 and the X carriage 160 and tilted vertically about the A axis. The resulting positions of the tool spindle 170, the Z3 carriage 240, and the pivot arm 250 are shown in FIGS. 5 and 6. This position is hereinafter also referred to as the "clamp position".

[0077] By moving the Z carriage 150 and / or the Z3 carriage 240, the tool 500 is positioned relative to the tool spindle 170 so that it can be clamped onto the tool spindle 170 by tool clamping means (not shown here).

[0078] After the tool is clamped onto the tool spindle 170, the tool gripper 260 is released and the pivot arm 250 is pivoted towards the rear of the machine. Here, the tool spindle 170, together with the X carriage 160, is moved out of the collision area with the pivot arm 250. Thereby, the pivot arm 250 can pivot back into the tool changer 200 without collision. Thereafter, the partition door 330 is closed again. Thus, the newly clamped tool 500 can machine the workpiece.

[0079] To remove the tool 500 from the tool spindle 170 again and move it into the tool magazine 220, this operation is performed in the reverse order.

[0080] Loading of a new tool into the tool magazine (FIGS. 7, 8, and 9A - 9D) Figures 7, 8, and 9A - 9D show the transfer of a tool to the external space of the machine and the loading of a new tool into the tool magazine. To transfer the tool 500 from inside the tool changer 200 to the outside of the machine, the tool is placed on the movable tool holder 230 (the "tool loading station") by appropriate movement of the Z3 carriage 240 and the pivot arm 250. During this time, the tool loading door 420 is closed. This state is shown in Figure 7. The corresponding positions of the Z carriage 240 and the pivot arm 250 are also hereinafter referred to as the "transfer position".

[0081] Here, the tool gripper 260 is opened and the pivot arm 250 pivots away from the tool 500. The movable tool holder 230 is in the home position located directly vertically below the fixed tool holders 221, 222, 223. This state is shown in Figure 8. Here, this position of the pivot arm 250 and the tool holder 230 also serves as the stationary position that the tool changer takes during operation pause.

[0082] Figures 9A - 9D show how to move the movable tool holder 230 from this home position to the loading position. In each of these figures, the same part of the tool changer is shown.

[0083] In Figure 9A, the movable tool holder 230 is in the home position and the tool loading door 420 is closed.

[0084] Next, open the tool loading door 420 to expose the tool loading opening 410. The movable tool holder 230 remains in its home position. This is shown in FIG. 9B. In this figure, it can also be seen that the movable tool holder 230 is movable relative to the support column 210. The linear guide 231 is firmly connected to the support column 210 via the holder 235 (see FIG. 9C). This linear guide is hereinafter also referred to as the loading linear guide or the X4 linear guide. In the X4 linear guide 231, the running rail 232 is slidably guided along the horizontal direction X4. The plate 233 is attached onto the running rail 232. The running rail 232 and the plate 233 together form a carriage, and the carriage is slidably guided in the X4 linear guide 231 and is hereinafter referred to as the loading carriage. The movable tool holder 230 is pivotally attached to the plate 233 via the pivot bearing 234. The pivot bearing 234 defines a pivot axis C4 extending vertically in the space (see FIG. 9C). Therefore, the pivot bearing 234 is also referred to as the loading pivot bearing. The loading pivot bearing 234 enables the movable tool holder 230 to pivot relative to the loading carriage in the horizontal pivoting plane.

[0085] Next, the loading carriage with the movable tool holder 230 attached and the tool 500 are manually pulled out through the tool loading opening 410 into the external space of the machine tool. The resulting intermediate position of the movable tool holder 230 is shown in FIG. 9C. In this intermediate position, the open side of the recess in the movable tool holder 230 faces towards the inside of the machine tool.

[0086] Finally, manually pivot the movable tool holder 230 further about the loading pivot axis C4 so that the open side of the recess in the movable tool holder 230 faces the operator. The resulting tool loading position of the tool holder 230 is shown in FIG. 9D. In this position, the operator can easily remove the tool 500 and place a new tool in the tool holder 230.

[0087] To load a new tool into the tool changer, the above-described steps are executed in reverse order. In order to ensure that the tool is received in the tool changer in a predetermined orientation about the axis of rotation, positioning elements can be present on the movable tool holder 230, which interact with complementary structures on the tool. For example, the tool can have orientation notches (a "German corner") in accordance with DIN 69893-1:2011-4, and complementary positioning pins can be provided on the movable tool holder 230.

[0088] After pushing the movable tool holder 230 with the new tool into the interior of the tool changer, the new tool can be transferred to one of the fixed tool holders 221, 222, 223 in the manner described above. As will be described in more detail below, it is preferred that the tool be pre-detected at the RFID station 600.

[0089] In the above example, the operation of the movable tool holder 230 is performed manually. However, it is also conceivable to control and execute these operations by means of a suitable drive unit. In particular, it is conceivable to perform an automatic exchange of tools between the movable tool holder 230 and an external magazine. For this purpose, the tool can be removed from the movable tool holder 230 and a new tool can be loaded by means of an external manipulator. In this case, the tool loading door 420 can be omitted.

[0090] It is also conceivable to design the movable tool holder 230 differently from the above example. For example, the movable tool holder 230 can be attached to a pivot arm, and the pivot arm can be used to pivot it into the external space through the tool loading opening 410.

[0091] If a tool loading door 420 is provided, it can be a sliding door instead of a rotary door.

[0092] [Detection of Tools by the RFID Station (Figs. 10 and 11)] As shown in FIG. 10, the tool 500 can be provided with an RFID transponder. FIG. 10 shows an exemplary tool 500. The tool 500 includes a tool support portion 510. At the upper end of the tool support portion 510, a hollow taper shank (HSK) 511 of type A compliant with DIN 69893-1:2011-04 or type F compliant with DIN 69893-6:2003-05 is provided. The tool support portion 510 has, on its outer periphery, the above-described orientation notch 513 (the “German corner”) compliant with DIN 69893-1:2011-4. At the lower end, a skiving wheel 520 having an end cutting edge 521 is connected to the tool support portion 510. Within the meaning of the present disclosure, the tool support portion 510 and the skiving wheel 520 together form the tool 500.

[0093] The skiving wheel 520 is provided with an RFID transponder 522 (the “RFID tag”). The RFID transponder 522 is located at the center on the lower side of the skiving wheel in the radial direction within the region where the cutting edge 521 of the skiving wheel is disposed. This RFID tag can uniquely identify the skiving wheel, and optionally, further characteristics of the skiving wheel can be stored in this tag.

[0094] To read the RFID transponder 522 by the RFID station 600, the Z3 carriage 240 is moved downward until the tool 500 held by the tool gripper 260 contacts the top of the RFID station 600. This state is shown in FIG. 11. This position of the Z3 carriage 240 and the pivot arm 250 is hereinafter also referred to as the “detection position”.

[0095] The RFID station 600 holds, on its top surface, an RFID transceiver 630 (visible in FIG. 4 but hidden by the tool in FIG. 11) that reads the RFID transponder 522. The RFID transponder 522 stores the unique identifier of the skiving wheel 520. This unique identifier is read by the RFID transceiver 630 and transmitted to the control device 180. Using the unique identifier, the control device 180 retrieves the process-related characteristics of the skiving wheel 520 from the database and uses these characteristics to control the machining process. These characteristics may include, for example, tool structure and geometric data, and data regarding previous use of the tool such as the number of regrinds performed and the number of times the workpiece has been machined since the last regrind. Alternatively, this data can be stored directly in the RFID transponder 522 and can also be read by the RFID transceiver 630. The RFID transceiver 630 can be further configured to write information to the RFID transponder 522.

[0096] To prevent damage to the RFID transceiver 630 and the associated RFID transponder 522, the RFID station 600 has a spring-loaded design. For this purpose, the RFID transceiver 630 is mounted on a transceiver mounting portion 620 that is guided vertically slidable on a base 610 via a guide rail 611. The base 610 is fixedly connected to the machine bed 110. A spring member 640 acts between the transceiver mounting portion 620 and the base 610 and is compressed when the transceiver mounting portion 620 moves below the guide rail 611. Thereby, the spring member 640 provides a restoring force to the transceiver mounting portion 620. The movement of the transceiver mounting portion 620 relative to the base 610 is preferably damped to prevent vibration. For example, the spring member 640 can be a gas spring known per se that generates both a restoring force and a damping effect. The spring-loaded design of the RFID station 600 enables the use of the RFID station 600 to read tools of different lengths without damaging the RFID transceiver 630 or the associated RFID transponder 522, even when the length of the tool is unknown.

[0097] The tool 500 is preferably detected by the RFID station 600 immediately after a new tool is loaded into the tool changer. Alternatively, this detection can also be performed when the tool is transferred to the tool spindle 170.

[0098] A further RFID transponder 512 is arranged in the peripheral region of the tool support 510. This RFID transponder is located in the installation space for the data carrier, as defined in DIN 69893-1:2011-04. This RFID transponder can be used to uniquely identify the tool support and, optionally, further characteristics of the tool support can be stored in this transponder. A second RFID transceiver (not shown) can be used to read the RFID transponder 512 in the tool support 510. This transceiver can be incorporated or located adjacent to the tool gripper 260, such as under the tool gripper.

[0099] The information read from the two RFID transponders 512 and 522 can be used to uniquely identify the tool 500 and verify that it is the correct combination of the skiving wheel 520 and the tool support 510.

[0100] Instead of the RFID transponders 512, 522, another type of machine-readable data carrier, for example an optical reading code, may be provided on the tool support 510 and / or the skiving wheel 520. Accordingly, instead of an RFID station, a reading station suitably configured, for example with an optical reading device for the data carrier instead of an RFID transceiver, can be provided.

[0101] Use for other objects (Figs. 12 and 13) Referring to Figs. 12 and 13, it is shown that objects other than the tool 500 can be received within the tool gripper 260.

[0102] For example, in the example of FIG. 12, for the tapered receptacle 171 in the tool spindle 170, the taper cleaner 530 is received by the tool gripper 260. The taper cleaner 530 can be a commercially available taper cleaner that is attached to a suitable connection with the tool gripper 260. The taper cleaner 530 is gripped by the tool gripper 260, moved by the pivot arm 250 and the Z3 carriage 240 to the tool spindle 170, and inserted into the slowly rotating tapered receptacle. Instead of the taper cleaner, for example, a brush may be used.

[0103] In the example of FIG. 13, the measurement probe 540 is received within the tool gripper 260. This measurement probe can perform general measurement and inspection functions. This measurement probe can be provided with wireless signal transmission means. For example, the measurement probe 540 can be used to perform measurements of the runout and axial runout of the work clamping means 140. For this purpose, the measurement probe 540 is moved by the pivot arm 250 and the Z3 carriage 240 to the work clamping means 140. Alternatively, the measurement probe 540 may be inserted at another location in the tool spindle 170 or the machine tool 100.

[0104] Instead of the taper cleaner 530 or the measurement probe 540, other objects may be gripped by the tool gripper 260. These objects can be placed in one of the tool trays when not in use.

[0105] Guide and drive of the Z3 carriage, drive of the pivot arm, locking of the tool gripper, auxiliary arm (FIGS. 14 and 15) For clarity, some components of the tool changer are not shown in FIGS. 1 to 13. FIGS. 14 and 15 show these components.

[0106] The Z3 carriage 240 is guided in a manner known per se by two parallel guide rails 241 firmly connected to the support column 210. The Z3 carriage is driven by a lifting carriage drive unit 242, which generates a rotational movement and converts it, by means of a ball screw 243 known per se, into a lifting movement of the Z3 carriage 240.

[0107] The pivoting movement of the pivot arm 250 about the C3 axis is effected by a pivot actuator 256 known per se, which is attached to the Z3 carriage 240.

[0108] The latch 257 fixes the auxiliary arm 252 to the pivot arm 250. This latch can be configured, for example, as a spring-loaded pin, which, in the latched position, passes through the pivot arm 250 and enters into an opening of the auxiliary arm 252 and, in the released position, is pulled sufficiently to enable the pivoting of the auxiliary arm 252 relative to the pivot arm 250.

[0109] The tool gripper 260 can be seen in more detail in FIG. 15. The tool gripper 260 is a two-jaw gripper known per se, comprising a pair of gripper jaws 261, 262 which are movable towards each other pneumatically or electrically in order to grip a tool. Thereby, the shape of the gripper jaws 261, 262 is adapted to the outer shape of the tool area picked up by the tool gripper. In particular, the gripper jaws 261, 262 can be shaped such that the tool gripped by the gripper jaws 261, 262 is fixed in a form-fitting manner so as not to fall off. For example, the tool support 510 can be provided with a type A hollow taper shank (HSK) conforming to DIN 69893-1:2011-04 or a type F hollow taper shank (HSK) conforming to DIN 69893-6:2003-05. Such a hollow taper shank has a collar with circumferential gripping grooves. Also, the gripper jaws can have inwardly projecting protrusions which engage in these gripping grooves.

[0110] The lifting carriage drive unit 242, the pivot drive unit 255, and the tool gripper 260 are controlled by the control device 180 (see FIG. 1).

[0111] Naturally, other types of guides, drive units, grippers, and latches are also conceivable.

[0112] [Second Embodiment (FIG. 16)] A second embodiment of the tool changer is shown in FIG. 16. The tool changer of the second embodiment differs from the tool changer of the first embodiment only with respect to the design of the tool gripper 260 and the way the tool gripper 260 is attached to the pivot arm 250.

[0113] In the second embodiment, the tool gripper 260 is configured as a double gripper. For this purpose, the tool gripper 260 includes two pairs of gripper jaws 261, 262 or gripper jaws 261', 262'. The pair of gripper jaws 261', 262' extends in a direction opposite to the pair of gripper jaws 261, 262. The tool gripper 260 is attached to a pivot body 263 integrated with a pivot drive unit at the free end of the pivot arm 250. This pivot body 263 enables the tool gripper to pivot between 0° and 360° about the vertical axis C6. Thereby, it becomes possible to interchange the positions of the pairs of gripper jaws 261, 262 and gripper jaws 261', 262'.

[0114] By designing the tool gripper 260 as a double gripper, it becomes possible to remove the worn tool 500' from the tool spindle 170 and replace it with a newly re-sharpened tool 500 without having to move the pivot arm 250 multiple times through the partition opening 320. For this purpose, in the method described above, a pair of gripper jaws 261, 262 takes out the newly re-sharpened tool 500 from the tool magazine. The pair of gripper jaws 261', 262' remains empty. Then, in the method described above, the pivot arm 250 transfers the tool 500 through the partition opening 320 to the tool spindle 170. Here, the pair of gripper jaws 261', 262' picks up the worn tool 500' from the tool spindle 170. The tool gripper 260 rotates 180°, and the pair of gripper jaws 261, 262 transfers the newly re-sharpened tool 500 to the tool spindle 170. Here, the pivot arm 250 rotates and returns inside the tool changer 200.

[0115] In this way, non-productive downtime during tool change can be reduced.

[0116] The pair of gripper jaws may be arranged differently from that in FIG. 16, and the tool gripper may be connected to the pivot arm 250 differently from that in FIG. 16. For example, the pair of gripper jaws can be arranged side by side on the same side of the tool gripper 260. It is also possible to provide two or more pairs of gripper jaws.

[0117] [Third Embodiment (FIG. 17)] The third embodiment of the tool changer is shown in Fig. 17. In the third embodiment, the tool gripper 260 is configured as a double gripper similar to that of the second embodiment and is rotatable about the vertical pivot axis C6 with respect to the pivot arm 250. The fixed tool holders 221, 222, 223 are configured here as double receptacles, that is, they can each receive two tools arranged side by side. The tool gripper 260 can be moved to the corresponding pivot position to place a tool in one of these tool holders or to pick up a tool from one of these tool holders. In this way, the capacity of the tool magazine 220 can be doubled with a minimum of additional space.

[0118] In addition, the tool changer of the third embodiment further includes a work gripper 270 that is optionally configured to pick up the work 800 from the work rest 280 and transfer it to the work clamping means 140 of the work spindle 130 at the corresponding position of the pivot arm 250. The control device 180 can have a corresponding control program for this purpose.

[0119] In this example, the work gripper 270 is also configured as a double gripper in order to minimize the non-productive idle time during work exchange. However, the work gripper 270 can of course also be configured as a single gripper. The work gripper 270 can also be combined with a single gripper for tools.

[0120] An optional tool cleaner 700 is disposed at the upper end of the column 201. The tool cleaner 700 is used to clean refrigerant and chips from the hollow tapered shank 511 (see FIG. 10) of the tool support portion 510 of the tool 500. Therefore, the tool cleaner 700 is also referred to as a taper cleaner. The tool cleaner 700 is arranged such that the tool 500 held by the gripper 260 can be easily moved to the tool cleaner by the Z3 carriage 240 and the pivot arm 250. In this example, the tool cleaner 700 is disposed above the fixed tool holders 221, 222, 223, but this is not essential.

[0121] Of course, the tool cleaner can be provided in any of the other embodiments described herein. Suitable tool cleaners are known from the prior art and are commercially available.

[0122] [Fourth Embodiment (FIG. 18)] A fourth embodiment of the tool changer is shown in FIG. 18. In this embodiment, the tool gripper 260 is linearly displaceable along the direction Y3 with respect to the pivot arm 250. For this purpose, the tool gripper 260 is mounted on the gripper carriage 265, and the gripper carriage 265 is displaceable in a controlled manner along the direction Y3 with respect to the pivot arm 250 by the gripper carriage drive unit 266.

[0123] In this example, the direction Y3 is substantially parallel to the longitudinal direction of the pivot arm 250, but can be at any angle with respect to that direction.

[0124] In this embodiment, the tool gripper can also be a double gripper as described with respect to the second and third embodiments. Also, the tool gripper can be mounted on the gripper carriage 265 via a pivot body. However, for example, when a pair of gripper jaws are arranged side by side, the pivot body can be omitted.

[0125] [Fifth Embodiment (Figs. 19 and 20)] A fifth embodiment of the tool changer is shown in Figs. 19 and 20. In this embodiment, the tool gripper 260 is attached to a pivot body 267 having an integral drive unit that enables the tool gripper 260 to pivot 90° in a controlled manner about a horizontal pivot axis C8 with respect to the pivot arm 250. As a result, the tool 500 can be arranged in the horizontal direction rather than the vertical direction in the tool holders 221, 222, 223, 224, and 230. Accordingly, the tool holders are each configured to receive the tool 500 in a direction such that the tool axis is horizontal. By arranging the tool horizontally, the space required for long tools is significantly reduced.

[0126] [Exchange of Clamping Means (Figs. 21 to 23)] The tool changer 200 not only enables automatic exchange of the tool on the tool spindle 170 but also enables assisting the operator in exchanging the work clamping means 140. This is shown in Figs. 21 to 23 with reference to the first embodiment.

[0127] To exchange the clamping means, the above-described auxiliary arm 252 is pivotally attached via a pivot bearing 253 to the free end of the pivot arm 250 below the tool gripper 260. During normal operation, the auxiliary arm 252 is locked to the pivot arm 250 in a stationary position. The above-described latch 257 is used for this purpose. The stationary position is monitored by a sensor (not shown) to prevent damage to the machine during normal operation. The auxiliary arm 252 can be unlocked to exchange the clamping means, and thereby can be manually pivoted about a vertical auxiliary pivot axis C5 in the horizontal plane with respect to the free end of the pivot arm 250. The auxiliary pivot axis C5 is arranged at a distance from the pivot axis C3 of the pivot arm 250. At the free end of the auxiliary arm 252, there is a bayonet receptacle 254 of the clamping means holder 255.

[0128] To perform the replacement of the clamping means, the Z carriage 150 first moves up to the top along the positive Z direction, the X carriage 160 moves to the far left along the negative X direction, i.e., away from the tool changer 200, to avoid collision between the pivot arm 250 and the auxiliary arm 252. The Y carriage 120 moves to the frontmost along the negative Y direction, enabling maximum access for the operator. Then, the Z3 carriage 240 and the pivot arm 250 move to the positions shown in FIGS. 21 and 22. Here, the operator releases the latch of the auxiliary arm 252 and manually swings the auxiliary arm 252 outward from the rest position. The operator attaches the clamping means holder 255 to the receptacle 254 and manually brings the auxiliary arm 252 to the position shown in FIGS. 21 and 22. The clamping means holder 255 is now directly above the clamping means 140. This position is also referred to as the clamping means replacement position.

[0129] By the downward movement of the Z3 carriage, the clamping means holder 255 is then placed on the clamping means 140. At this time, the clamping means holder 255 is connected to the clamping means 140, for example, by a screw connection and released from the work spindle 130. By the upward movement of the Z3 carriage 240, the clamping means 140 rises from the work spindle 130 and swings forward and outward from the machining space of the machine tool 100 by the auxiliary arm 252. The resulting removal position is shown in FIG. 23. Then, the clamping means 140 can be placed on a clamping means rest (not shown), for example, on a carriage, by the downward movement of the Z3 carriage 240.

[0130] To prevent unnecessary pivoting movement of the auxiliary arm 252, a detent mechanism can be provided on the pivot bearing 253 to lock the auxiliary arm 252 in one or more selected detent positions. This detent mechanism can be configured such that the auxiliary arm 252 can pivot out of these detent positions only after overcoming a specific release torque around the auxiliary pivot axis C5. For this purpose, the detent mechanism can include, for example, spring thrust pieces that engage in respective recesses in the control plate of the pivot bearing at the detent positions. Alternatively, manual-operable clamping means can be provided to enable fixing the auxiliary arm 252 in any pivoting position, or the pivot bearing 253 can be configured to provide a certain degree of friction against the pivoting movement to prevent accidental pivoting of the auxiliary arm 252.

[0131] To prevent damage to the clamping means 140 when the clamping means holder 255 is placed on the clamping means 140, the clamping means holder 255 can be formed to receive a spring load during compression along the Z direction.

[0132] Although the replacement of the clamping means has been described with reference to the first embodiment, the replacement of the clamping means can be carried out in a very similar manner in all other embodiments.

[0133] [Modification with a force transducer (FIG. 24)] The receptacle 254 for the clamp means holder 255 can be attached to the auxiliary arm 252 via a force transducer 258. This is shown in FIG. 24. The force transducer 258 measures the force exerted by the weight of the clamp means 140 suspended from the attachment portion 253. The force transducer 258 transmits a signal indicating the measured force to the control device 180, thereby enabling the control device 180 to detect an excessive load on the system including the pivot arm 250 and the auxiliary arm 252 and, accordingly, warn the operator to stop further operation of the tool changer if necessary. The warning can also be issued, for example, when the connection between the clamp means 140 and the work spindle 130 is not properly released and the clamp means 140 cannot be lifted.

[0134] Suitable force transducers are known in the prior art and are commercially available.

[0135] The force transducer in FIG. 24 is shown in combination with the fourth embodiment, but the force transducer can also be used in any other embodiment.

[0136] [Other Variations] Naturally, various further variations of the tool changer described above are possible without departing from the scope of the invention defined in the claims.

[0137] For example, it is also conceivable to design the support structure differently from that shown above. For example, instead of a single column 210, two parallel columns can be provided as the support structure, with the tool holder attached to one of these columns and the other column functioning to guide the Z3 carriage. [Description of Reference Numerals]

[0138] 100 Machine tool 110 Machine bed 111 Horizontal section 112 Vertical section 120 Y carriage 130 Work spindle 140 Work clamping means 150 Z carriage 160 X carriage 170 Tool spindle 171 Taper receptacle 180 Control device 200 Tool changer 210 Support column 220 Tool magazine 221 - 224 Tool holders (tool storage locations) 230 Movable tool holder (tool loading station) 231 X4 guide 232 X4 running rail 233 Plate 234 Pivot bearing 235 Holder 240 Lifting carriage (Z3 carriage) 241 Guide rail 242 Lifting carriage drive unit 243 Ball screw 250 Pivot arm 251 Pivot bearing 252 Auxiliary arm 253 Pivot bearing 254 Receptacle 255 Clamping means holder 256 Pivot drive unit 257 Latch of auxiliary arm 258 Force converter 260 Tool gripper 261, 262 Gripper jaws 261’, 262’ Gripper jaws 263 Pivot bearing with drive unit 265 Gripper carriage 266 Gripper carriage drive unit 267 Pivot body with drive unit 270 Work gripper 280 Work rest 300 Partition Partition wall 310 Partition opening 320 Partition door 330 Apron 340 Outer wall 400 Tool loading opening 410 Tool loading door 420 Tools 500, 500’ Tool support part 510 Hollow tapered shank 511 RFID transponder 512 Orientation notch (“German corner”) 513 Skyving wheel 520 Cutting edge 521 RFID transponder 522 Taper cleaner 530 Measurement probe 540 RFID station 600 Base 610 Guide rail 611 Transceiver mounting part 620 RFID transceiver 630 Spring member 640 Tool cleaner 700 Workpiece 800 Linear axes of the machine tool X, Y, Z Pivot axis of the tool spindle A Tool axis B Work axis C Linear axis of the Z3 carriage Z3 Linear axis of the gripper carriage Y3 Pivot axis of the pivot arm C3 Displacement direction of the movable tool holder X4 Pivot axis of the movable tool holder C4 Auxiliary pivot axis of the auxiliary arm C5 Vertical pivot axis of the tool gripper C6 Vertical pivot axis of the workpiece gripper C7 Horizontal pivot axis of the tool gripper C8

Claims

1. A tool changing device (200) for changing a tool (500) in a machine tool (100), particularly in a milling machine, comprising: a support structure (210); a lifting carriage (240) guided on the support structure (210) along a lifting direction (Z3) extending vertically in the space; a pivot arm (250) pivotally attached to the lifting carriage (240) so as to be pivotable about a pivot axis (C3) extending vertically in the space; a tool gripper (260) attached to the pivot arm (250) and configured to grip a tool (500); a tool magazine (220) comprising a plurality of tool holders (221, 222, 223, 230) arranged vertically one above the other; and the tool changing device (200) is configured to selectively move the tool (500) gripped by the tool gripper (260) between one of the tool holders (221, 222, 223, 230) and a tool spindle (170) of the machine tool (100) or between two different tool holders (221, 222, 223, 230) of the tool magazine (200) by a combination of a lifting movement and a pivoting movement of the pivot arm (250); the support structure (210) includes a vertical column configured such that a lower end thereof is attached to a machine bed (110) of the machine tool (100); the lifting carriage (240) is guided along the lifting direction (Z3) on the column; the tool holders (221, 222, 223, 230) are attached to the column, the tool changing device.

2. The tool changing device (200) according to claim 1, wherein one of the tool holders (230) is movably attached to the support structure (210), particularly displaceable along a horizontal loading direction (X4) and / or pivotable about a vertical loading pivot axis (C4) so as to facilitate loading of the tool magazine (220).

3. The tool changing device (200) according to claim 2, comprising an outer wall (400) separating an internal space of the tool changing device (200) from an external space, wherein the outer wall has a tool loading opening (410) for exchanging a tool (500) between the internal space and the external space. The movable tool holder (230) is a tool changing device that is movable through the tool loading opening (410).

4. The tool changing device (200) according to claim 3, comprising a tool loading door (420) configured to selectively open and close the tool loading opening (410).

5. The tool changing device (200) according to any one of claims 2 to 4, a loading linear guide (231), a loading carriage (232, 233) guided on the loading linear guide (231) so as to be displaceable along the horizontal loading direction (X4), comprising The movable tool holder (230) is attached to the loading carriage (232, 233) so as to be pivotable about the vertical loading pivot axis (C4).

6. The tool changing device (200) according to any one of claims 1 to 5, further comprising a partition (300) configured to separate the internal space of the tool changing device (200) from the machining space of the machine tool (100), the partition (300) having a partition opening (320), the tool changing device (200) comprising a partition door (330) configured to selectively open and close the partition opening (320), the pivot arm (250) to which the tool gripper (260) is attached is movable through the partition opening (320) at at least one position of the lifting carriage (240).

7. The tool changing device (200) according to any one of claims 1 to 6, further comprising a reading station (600) for reading a machine-readable data carrier (521) on the tool (500), the reading station (600) being arranged such that the tool (500) is movable to the reading station (600) by a combination of the lifting and pivoting movements of the pivot arm (250) for reading the data carrier (521) on the tool (500) held by the tool gripper (260).

8. The tool changing device (200) according to claim 7, wherein the reading station (600) includes a base (610), a reading device (630) for reading the data carrier (521), and a spring member (640) disposed between the base (610) and the reading device (630), and the reading device (630) is movable vertically downward with respect to the base (610) against the restoring force provided by the spring member (640).

9. The tool changing device (200) according to any one of claims 1 to 8, further comprising a tool cleaner (700). The tool cleaner (700) is arranged such that the tool (500) held by the tool gripper (260) can be moved toward the tool cleaner (700) by a combination of the lifting and turning movements of the pivot arm (250) in order to clean the tool support portion (510) of the tool (500).

10. The tool changing device (200) according to any one of claims 1 to 9, wherein the tool gripper (260) is configured as a plurality of grippers having at least two pairs of gripper jaws (261, 262; 261', 262') for gripping two or more tools (500, 500').

11. The tool changing device (200) according to any one of claims 1 to 10, wherein the tool gripper (260) is movably, particularly pivotably, and / or displaceably, particularly linearly displaceably along the horizontal gripper displacement direction (Y3), attached to the pivot arm (250).

12. The tool changing device (200) according to any one of claims 1 to 11. A taper cleaner (530) for cleaning the taper receptacle (171) of the tool spindle (170), and / or Particularly, further comprising a measuring probe (540) for measuring the radial and axial runout of the work clamping means (140) of the machine tool (100). The taper cleaner (530) can be gripped by the tool gripper (260) so as to be movable toward the tool spindle (170) by a combination of the lifting and turning movements of the pivot arm (250). The tool changing device is such that the measurement probe (540) can be gripped by the tool gripper (260) so as to be movable to a measurement position by a combination of the elevating and swinging movements of the pivot arm (250).

13. A tool changing device (200) according to any one of claims 1 to 12, further comprising a work gripper (270) which is mounted on the pivot arm (250) and is configured to pick up a workpiece (800) from a work rest (280) and transfer it to a work spindle (130) of the machine tool (100).

14. A tool changing device (200) according to any one of claims 1 to 13, an elevating carriage drive unit (242) for driving the elevating carriage (240) so as to perform an elevating movement along the elevating direction (Z3), a pivot drive unit (256) for driving the pivot arm (250) so as to perform a swinging movement with respect to the elevating carriage (240) about the pivot axis (C3), and a control device (180) configured to control the elevating carriage drive unit (242), the pivot drive unit (256), and the tool gripper (260). The tool changing device further comprising the above components.

15. A tool changing device (200) according to claim 14, wherein the control device (180) is configured to perform at least one of the following operations: a) gripping a tool (500) by the tool gripper (260), b) moving the tool (500) gripped by the tool gripper (260) between one of the tool holders (221, 222, 223, 230) and the tool spindle (170) of the machine tool (100) by a combination of the elevating and swinging movements of the pivot arm (250), c) moving the tool (500) gripped by the tool gripper (260) between two different tool holders (221, 222, 223, 230) of the tool magazine (220) by a combination of the elevating and swinging movements of the pivot arm (250), d) opening and closing a partition door (330) when the tool changing device is configured according to claim 6. e) When the tool changing device is configured according to claim 7 or 8, moving the tool (500) gripped by the tool gripper (260) to the reading station (600) by a combination of the lifting and turning movements of the pivot arm (250), and reading the data carrier (521) on the gripped tool (500), f) When the tool changing device is configured according to claim 9, moving the tool (500) gripped by the tool gripper (260) to the tool cleaner (700) by a combination of the lifting and turning movements of the pivot arm (250), and cleaning the tool support portion (510) of the gripped tool (500) by the tool cleaner (700), g) When the tool changing device is configured according to claim 11, moving the tool gripper (260) relative to the pivot arm (250), h) When the tool changing device is configured according to claim 12, moving the taper cleaner (530) gripped by the tool gripper (260) to the tool spindle (170) by a combination of the lifting and turning movements of the pivot arm (250), j) When the tool changing device is configured according to claim 12, moving the measuring probe (540) gripped by the tool gripper (260) to the measuring position by a combination of the lifting and turning movements of the pivot arm (250), k) When the tool changing device is configured according to claim 13, gripping the workpiece (800) by the workpiece gripper (270), and moving the workpiece (800) gripped by the workpiece gripper (270) between the workpiece rest (280) and the workpiece spindle (130) of the machine tool (100) by a combination of the lifting and turning movements of the pivot arm (250). **Claim 16** A tool changing device (200) according to any one of claims 1 to 15, further comprising an auxiliary arm (252) pivotally attached to the pivot arm (250) so as to be pivotable about an auxiliary pivot axis (C5) extending in the vertical direction, wherein the auxiliary pivot axis (C5) of the auxiliary arm (252) and the pivot axis (C3) of the pivot arm (250) are parallel and spaced apart from each other, The auxiliary arm (252) is a tool changing device configured to be attached with a work clamping means (140) of the machine tool (100).

17. The tool changing device (200) according to claim 16, wherein the auxiliary arm (252) is lockable to the pivot arm (250) in a stationary position in order to prevent a turning movement of the auxiliary arm (252) around the auxiliary pivot axis (C5), the tool changing device.

18. The tool changing device (200) according to claim 16 or 17, wherein the tool changing device further comprises a clamp means holder (255) configured to be removably connected to the auxiliary arm (252) and the work clamping means (140), and the work clamping means (140) is attached to the auxiliary arm (252) via the clamp means holder (255), in particular is suspended, the tool changing device further comprising the clamp means holder (255).

19. The tool changing device (200) according to any one of claims 16 to 18, wherein a force transducer (258) is arranged on the auxiliary arm (252) so as to detect a load on the auxiliary arm (252) in the vertical direction, the tool changing device.

20. A machine tool (100), comprising a machine bed (110); a tool spindle (170) for driving a tool (500) to rotate about a tool axis (B); the tool changing device (200) according to any one of claims 1 to 18; and is provided with the tool changing device (200) is arranged on the machine bed (110) such that a tool (500) gripped by the tool gripper (260) is movable from one of the tool holders (221, 222, 223, 230) to the tool spindle (170) by a combination of a lifting movement and a turning movement of the pivot arm (250), the machine tool.

21. The machine tool (100) according to claim 20, wherein the tool spindle (170) is pivotally arranged in the machine tool (100) such that the tool axis (B) can be brought to a position extending vertically in space, the machine tool.

22. The machine tool (100) according to claim 20 or 21, further comprising a work spindle (130) having a work clamping means (140). The tool changer (200) is formed according to any one of claims 16 to 19, The work spindle (130) is a machine tool arranged on the machine bed (110) such that the work clamping means (140) can be attached to the auxiliary arm (252) when the auxiliary arm (252) pivots outward from the stationary position with respect to the pivot arm (250).

23. Use of a tool changer (200) according to any one of claims 16 to 19 for replacing work clamping means (140) in a machine tool (100).

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