Apparatus and method for loading and unloading a machine tool for machining gears, and associated machine tool comprising the apparatus

Abstract

A device (1) for loading and unloading workpieces (40, 41) for a machine tool (30) for machining teeth, particularly a hard finishing machine (30), the device (1) comprising: a base (2); a carrier (3) disposed on the base (2) and rotatable relative to the base (2) about a first rotation axis (D1); and a gripping device (11) disposed on the carrier (3) for gripping and releasing the workpieces (40, 41), wherein the gripping device (11) has at least two gripping arms (13, 14, 15). They can pivot independently about the second rotation axis (D2), and the gripping arms (13, 14, 15) can pivot relative to each other about the second rotation axis (D2), such that the gripping arms (13, 14, 15) can be in a gripping position for gripping workpieces (40, 41) and a releasing position for releasing workpieces (40, 41) relative to each other, and the gripping arms (13, 14, 15) can pivot synchronously about the second rotation axis (D2) at least in the gripping position.

Description

Technical Field

[0001] This invention relates to an apparatus for loading and unloading workpieces for a machine tool used for machining teeth. The apparatus includes a base and a carrier disposed on the base. The carrier is rotatable relative to the base about a first rotation axis and includes a gripping device for gripping and releasing the workpiece.

[0002] The present invention also relates to a machine tool for grinding teeth on workpieces, wherein the machine tool has the apparatus of the type described above. Furthermore, the present invention relates to a method for loading and unloading materials for a machine tool using the apparatus of the present invention. Prior Technology

[0003] The so-called ring loader design is known in the prior art. Devices employing a ring loader design have a gripping mechanism, which is typically rotatable about a rotation axis, and include multiple pairs of gripping arms. Each pair of gripping arms is designed to grip or release workpieces independently of the other pairs. To transport one or more workpieces, the gripping mechanism rotates about the rotation axis after at least one pair of gripping arms has gripped a workpiece. This causes all pairs of gripping arms, including the pair that has gripped the workpiece, to pivot simultaneously about the rotation axis.

[0004] A drawback of such conventional devices in the prior art is that the gripping mechanism is constructed such that the position of one pair of gripping arms relative to another pair of gripping arms is fixed, or cannot be changed. This means that when the gripping mechanism rotates about its axis of rotation, all pairs of gripping arms will pivot simultaneously. The gripping arms cannot be flexibly used to grip or release workpieces. This reduces or limits the loading and unloading speed of the conventional device. Furthermore, the maintainability of the conventional device is also limited, especially because the gripping mechanism is usually spatially fixed relative to the machine tool to be loaded or unloaded. Summary of the Invention

[0005] The object of this invention is to provide a device for loading and unloading workpieces for machine tools, belonging to the technical field described at the outset, which eliminates the aforementioned problems and disadvantages of the prior art. Specifically, the object of this invention is to provide a device for loading and unloading workpieces for machine tools, which can quickly and efficiently load and unload workpieces, and also has higher maintainability.

[0006] To achieve this objective, the device of the present invention for loading and unloading workpieces for a machine tool includes a base, a carrier, and a gripping device. This device is preferably suitable for loading and unloading workpieces for hard finishing machines, particularly workpieces with pre-formed teeth, such as double-tooth gear blanks.

[0007] As an alternative or supplementary solution, this device may be adapted to load and unload fixtures, grinding wheels, or similar components provided for machine tools. That is, for the purposes of this invention, the term "workpiece" is not limited to objects processed by machine tools. Rather, the term "workpiece" may also include components provided for machine tools, particularly components provided for the operation and / or maintenance of machine tools.

[0008] The carrier of the device of the present invention is arranged on a base and is rotatable relative to the base about a first rotation axis. A gripping device is disposed on the carrier and is designed to grip and release workpieces. The gripping device is advantageously arranged on the carrier such that it pivots about the first rotation axis as the carrier rotates about the first rotation axis.

[0009] According to the present invention, the gripping device includes at least two gripping arms. The gripping arms are independently pivotable about a second rotation axis. Each gripping arm is pivotable relative to the other gripping arm about the second rotation axis, such that the at least two gripping arms are in a gripping position and a release position relative to each other. In the release position, the gripping arms are arranged relative to each other such that they can release a workpiece. That is, the gripping arms in the release position preferably cannot transport a workpiece. In the gripping position, the gripping arms are arranged relative to each other such that they can grip a workpiece, preferably gripping the workpiece together. For example, the gripping arms in the gripping position can transport a workpiece, and in particular, can transport the workpiece together. Furthermore, the gripping arms can pivot synchronously about the second rotation axis at least in the gripping position. Alternatively, the gripping arms can be configured to pivot synchronously about the second rotation axis in the release position.

[0010] For the purposes of this invention, the term "grip" is understood to mean holding a workpiece, particularly clamping or locking it between two gripping arms. Alternatively or supplementary, the term "grip" may also include holding the workpiece with the gripping arms. Preferably, the gripping arms are connected to the workpiece in a force-locking and / or form-fitting manner in the gripping position.

[0011] For the purposes of this invention, the term "release" is understood as releasing the contact between the gripper arm and the workpiece. For example, the contact between the gripper arm and the workpiece can be released when the gripper arm switches from the gripping position to the releasing position. Preferably, the workpiece is considered to have been released when it is in contact with only one gripper arm.

[0012] For the purposes of this invention, the term "synchronous pivoting" is understood as the simultaneous pivoting of the gripping arms, wherein the relative positions of the gripping arms do not change. For example, the gripping arms may pivot synchronously in the gripping position to transport the workpiece between the gripping arms according to the pivoting movement of the gripping arms. In other words, when the gripping arms pivot synchronously about a second axis of rotation, the workpiece located between the two gripping arms in the gripping position pivots about the second axis of rotation.

[0013] According to the present invention, the gripping arms are pivotable relative to the second rotation axis, meaning that the gripping arms can be flexibly controlled independently of each other. The advantage is that different gripping arms can be configured into different gripping arm pairs as needed, thus enabling faster loading and unloading of workpieces for the machine tool. Furthermore, the spacing between the gripping arms in the released position is sufficient to allow for smooth workpiece machining by the machine tool. For example, the gripping arms can pivot relative to each other about the second rotation axis in the released position, such that the distance between the gripping arms is greater than the width of the grinding wheel of the machine tool's grinding device. Further, or additionally, the arrangement of the gripping device on the rotatable carrier improves the accessibility of each component. This improves the maintainability of the entire device.

[0014] In a first exemplary embodiment of this device, a workpiece spindle is provided on the carrier. The workpiece spindle is designed to rotate a workpiece disposed on the workpiece spindle. The gripping device is advantageously designed to load and unload workpieces onto and off the workpiece spindle. For example, the gripping arm of the gripping device can be configured to switch from a gripping position to a release position, or vice versa, at a loading point in order to release or grip the workpiece. Preferably, the loading point is located near the workpiece spindle, particularly above the workpiece spindle.

[0015] The embodiment in which the workpiece spindle is mounted on the carrier has the following advantages: when the carrier rotates about the first rotation axis, the workpiece spindle will pivot about the first rotation axis. This is advantageous because it makes the workpiece spindle more accessible, improving maintainability, or it allows the workpiece spindle to be moved to a measuring position. Furthermore, manually loading the workpiece spindle is also advantageous when the carrier is rotated to allow the user to access it.

[0016] The workpiece spindle can rotate about a third rotational axis, and more particularly, can rotate about a third rotational axis. Preferably, the third rotational axis is offset parallel to the first rotational axis. Alternatively or as a supplement, the third rotational axis can be arranged offset parallel to the second rotational axis.

[0017] In another exemplary embodiment, the gripping device can move along a second rotation axis, particularly axially. Preferably, the gripping device moves along the second rotation axis after the gripping arm switches from the gripping position to the release position and / or from the release position to the gripping position. This advantageously allows the gripping device to lift or lower the workpiece, particularly after the gripping arm switches from the release position to the gripping position, or before the gripping arm switches from the gripping position to the release position.

[0018] The second rotation axis is preferably offset parallel to the first rotation axis. This advantageously allows for a compact design and improves the accessibility of the components. Furthermore, the offset of the two rotation axes means that the device can be in multiple adjustable positions, which enhances its flexibility of use.

[0019] In another advantageous embodiment, the gripping device can grip or release the workpiece regardless of the carrier's position. For example, the gripping device can be designed to grip or release the workpiece regardless of the carrier's position relative to the first axis of rotation. Alternatively or supplementarily, the gripping device can be configured to grip or release the workpiece during the carrier's rotational movement relative to the first axis of rotation. Such an embodiment advantageously allows the device to load and unload machine tools in a highly flexible manner. In particular, it is conceivable that the device can load the machine tool while the carrier is in a maintenance position. Its advantage is that the device can be kept in a continuous standby state, i.e., at least partially guaranteed even during maintenance work.

[0020] Such a device for loading and unloading materials for machine tools may include a drive mechanism. Preferably, the gripping device includes the drive mechanism. The drive mechanism is arranged, for example, on the gripping device, particularly directly on the gripping device. The drive mechanism can be designed to drive the gripping arms independently. The advantage of this drive mechanism is that the gripping arms can always pivot independently about a second rotation axis. The drive mechanism is preferably designed as a rotary drive.

[0021] In an improved embodiment described above, the drive device includes multiple drive components. These drive components may be, for example, electric motors and / or synchronous motors. Each drive component may correspond to a gripping arm. For example, a first drive component may correspond to a first gripping arm, and a second drive component may correspond to a second gripping arm. The advantage of a drive device with multiple drive components is that the gripping arms can always pivot independently about a second rotation axis. In particular, in the event of a failure of one drive component, it can be ensured that other drive components continue to drive other gripping arms. For example, the drive components may be designed to switch to an idling mode in the event of a failure, thereby allowing the corresponding gripping arm to pivot freely about the second rotation axis.

[0022] Each gripping arm can be mounted on a drive ring. Each drive ring is mounted to rotate about a second rotation axis. For example, the drive rings can be rotatably mounted in the base of the gripping device via rolling bearings and / or sliding bearings. When the corresponding drive ring rotates about the second rotation axis, the gripping arm corresponding to that drive ring pivots about the second rotation axis. The advantage of a direct one-to-one correspondence between gripping arms and drive rings is that the gripping arms can be driven independently of each other. The drive rings can be annular, particularly circular, semi-annular, or partially annular. The drive rings can be connected to the corresponding gripping arms using force-locking, form-fitting, and / or material bonding methods. Alternatively, it is conceivable that the drive rings and the corresponding gripping arms are integrally formed, particularly molded together. Preferably, each gripping arm is arranged relative to the second rotation axis on the radially outer surface of the corresponding drive ring.

[0023] In an improved embodiment of this device with drive members and drive rings, each drive ring may have internal teeth, and each drive member may have a spur gear with external teeth. The drive members and drive rings are advantageously arranged opposite each other such that the external teeth of one drive member mesh with the internal teeth of one drive ring. This meshing advantageously has the effect that the rotational motion generated by the drive members is transmitted to the corresponding drive rings, thereby causing the drive rings to rotate about a second rotation axis. In particular, the gripping arms arranged on the corresponding drive rings are thus driven. The advantage of this improved embodiment is that the rotational motion generated by the drive members can be transmitted to the drive rings with almost no loss, and consequently to the corresponding gripping arms.

[0024] As an alternative or supplementary solution, the drive member can also drive the drive ring through other drive connections. For example, external teeth can be provided on one or more drive rings, and the corresponding drive member meshes with these external teeth. Alternatively, a chain driver and / or belt driver can be provided as a drive connection between the drive ring and the drive member. A linear motor can also be used.

[0025] As an alternative, an arc-shaped guide can also be used to guide the gripper arm.

[0026] A transmission device can also be installed between the drive unit and the gripping arm. For example, a transmission device can be installed between each drive member and the corresponding drive ring. Alternatively, the transmission device can be arranged only between a single drive member and the drive ring. The transmission device can be designed to change the speed and / or reduce the rotational motion of the drive unit (especially the associated drive member). In particular, the use of a transmission device may be advantageous when the gripping arm must pivot about a second axis of rotation with very fine degrees and / or when an increased gripping force is required.

[0027] In another exemplary embodiment, a gripping member may be provided on one, more, or all of the gripping arms. Alternatively, multiple gripping members may be arranged on a single gripping arm. The gripping members are advantageously arranged on the respective gripping arms such that they face the corresponding gripping arm, and in particular, the gripping member facing the corresponding gripping arm. The gripping members are preferably designed to contact the workpiece when the gripping arm is in the gripping position. For example, the gripping members may be designed to apply a clamping force to the workpiece in the gripping position. Alternatively or supplementary, the gripping members may have protrusions capable of supporting the workpiece. That is, particularly when the respective gripping arm switches from the release position to the gripping position, or is in the gripping position, the workpiece is supported by the protrusions of one or more gripping members.

[0028] The gripping component advantageously improves the force engagement and / or form fit between the gripping arm and the workpiece at the gripping position. Its advantage lies in the more secure transport of the workpiece by the gripping device, and in particular, its more secure pivoting about the second axis of rotation.

[0029] The gripping device can be designed to grip multiple workpieces simultaneously. This will advantageously enable the device used for loading and unloading machine tools to load and unload machine tools faster and more efficiently.

[0030] In one exemplary embodiment, the gripping device may have a first gripping arm, a second gripping arm, and a third gripping arm. Preferably, the second gripping arm is arranged circumferentially between the first and third gripping arms on the second rotation axis. In other words, the order of the gripping arms on the second rotation axis can be constant and is not affected by specific positions (gripping position and / or release position). Advantageously, this makes the gripping device very easy to control. Its advantage lies in the fact that the manufacture and operation of this device for loading and unloading machine tools can be carried out in a cost-effective and time-saving manner.

[0031] In an improved embodiment described above, the gripping device can be designed such that the second gripping arm can be in a gripping or releasing position relative to the first gripping arm. Alternatively, the second gripping arm can be configured to be in a gripping or releasing position relative to the third gripping arm. In other words, the second gripping arm can be designed to be in a gripping and / or releasing position on both sides. The second gripping arm can contact one workpiece on each side of the second rotation axis in the circumferential direction. This improved embodiment advantageously has the following effect: regardless of the position of the second gripping arm relative to the third gripping arm, a workpiece can be gripped between the first and second gripping arms. The reverse is also true. That is, regardless of the position of the second gripping arm relative to the first gripping arm, a workpiece can be gripped between the second and third gripping arms. The advantage of the improved scheme of circumferentially positioning the second gripping arm between the first and third gripping arms is that, for example, the gripping device can separately perform actions such as not gripping and / or releasing any workpiece, gripping and / or releasing workpieces between the first and second gripping arms, gripping and / or releasing workpieces between the second and third gripping arms, or gripping and / or releasing two workpieces simultaneously. This ensures fast, efficient, and flexible loading and unloading.

[0032] In another exemplary embodiment of this device, the carrier is rotatable about a first rotation axis, thereby allowing the carrier to be adjusted between an operating position and a maintenance position. Specifically, the carrier is rotatable about the first rotation axis to allow it to switch back and forth between the operating and maintenance positions. Preferably, the machine tool is loaded and unloaded from workpieces using this device in the operating position. Maintenance can be performed on the machine tool and / or device in the maintenance position. Alternatively or supplementary, one or more workpieces can be manually loaded onto the machine tool and / or device in the maintenance position. The advantage is that the device is easily accessible to the user.

[0033] The carrier can be mounted on the base using a hydrostatic method. In particular, to improve the carrier's rotatability about a first rotation axis, it can be mounted on the base using a hydrostatic method. The advantage is that even under heavy loads, especially when the workpiece is heavy, with a weight, for example, greater than 100 kg, the carrier can still rotate relative to the first rotation axis, and in particular, rotate flexibly. Furthermore, the hydrostatic mounting provides high rigidity to the connection between the carrier and the base and facilitates precise positioning.

[0034] In addition, the carrier may have a carrier tower. The carrier tower is preferably arranged vertically on the carrier. Furthermore, the carrier tower may be eccentrically positioned on the carrier relative to a first axis of rotation. The outer surface of the carrier tower may radially restrict the carrier tower relative to a second axis of rotation. A gripping device, for example, is arranged on the outer surface of the carrier tower. Advantageously, this makes the gripping device easily accessible during maintenance.

[0035] A dressing device may be provided on the carrier. The dressing device may be designed to dress the grinding wheel of a machine tool's grinding unit. Preferably, the dressing device is arranged radially offset on the carrier relative to a first axis of rotation. This has the following effect: when the carrier rotates, for example, around the first axis of rotation, the dressing device pivots around the first axis of rotation. Its advantage is that by rotating the carrier around the first axis of rotation, the dressing device can be positioned relative to the grinding wheel, allowing the grinding wheel to be dressed by the dressing device. For this purpose, the carrier may, for example, be in a dressing position. Furthermore, by rotating the carrier around the first axis of rotation, the dressing device can be made more easily accessible to the user, especially during maintenance work.

[0036] In an exemplary improvement of the above embodiments, the dressing device is movable relative to the carrier. Preferably, the dressing device is translatably movable relative to the carrier. Specifically, the dressing device is movable relative to the carrier such that the translational movement of the dressing device causes a change in the distance between the dressing device and the first rotation axis. In other words, the translational movement of the dressing device is orthogonal to the first rotation axis. For example, the dressing device may move 100 mm to 200 mm relative to the carrier, preferably 125 mm to 175 mm, most preferably 150 mm, particularly moving away from the carrier. This advantageously has the effect of effectively preventing collisions with the gripping device. Furthermore, or in addition, the distance between the dressing device and the carrier helps to significantly reduce contamination of the gripping device by abrasive shavings generated, for example, during the dressing of abrasive molds.

[0037] As an alternative or supplementary option, the trimming device can rotate relative to the carrier. For example, the trimming device can pivot relative to the carrier about a pivot axis. The pivot axis of the trimming device can be parallel to the first rotation axis. If the trimming device can translate and rotate relative to the carrier, the translational movement of the trimming device can cause a change in the distance between the pivot axis of the trimming device and the first rotation axis.

[0038] By configuring the dressing device to be movable relative to the carrier, it is advantageous to have the effect of positioning the dressing device particularly well relative to the grinding wheel. Its advantage lies in the fact that the dressing device can perform particularly precise dressing of the grinding wheel.

[0039] In another exemplary embodiment, the device includes a contouring device. The contouring device can be designed to contour, particularly pre-contour, an abrasive tool of a grinding apparatus. For example, the contouring device may have a rotating cutting edge over which the abrasive tool can rotate to form a tooth profile on the abrasive tool. The contouring device is preferably arranged on a gripping device, particularly on a drive ring or the base of the gripping device. This arrangement of the contouring device advantageously allows it to move axially relative to a second rotational axis and / or pivot about the second rotational axis. Its advantage is that the contouring device can be positioned particularly well relative to the abrasive tool.

[0040] In another exemplary embodiment, the device includes a centering device. The centering device can be designed to orient, particularly center, a workpiece relative to another component of the device and / or relative to a component of the machine tool. For example, the centering device can be configured to orient, particularly center, the workpiece relative to a workpiece spindle. As a supplementary or alternative, the centering device can be designed to support the workpiece. For example, the centering device can support the workpiece when it is driven by the workpiece spindle. The centering device is preferably a tailstock. An advantage of embodiments with a centering device is that the machine tool can be loaded very precisely by this device and / or the workpiece position can be maintained during machining. This particularly improves the accuracy of the machine tool. Consequently, manufacturing tolerances of the workpiece can be advantageously minimized.

[0041] This device may include a position measuring device. Preferably, the position measuring device is designed to detect the position of the workpiece, particularly the position of at least one tooth backlash of the workpiece. The position measuring device detects the position of the workpiece, for example, after the workpiece has been loaded onto the machine tool. Alternatively or supplementarily, the position measuring device detects the position of the workpiece after the gripping device has positioned it on the workpiece spindle. The position measuring device may be designed, in particular, to determine the position of the tooth surface or backlash of the workpiece. Alternatively or supplementarily, the position measuring device may be designed to determine the position of the gripping arm, particularly the position of the gripping arm relative to a second rotation axis.

[0042] To determine a specific position, the position measuring device may include at least one sensor. This sensor may be an optical sensor and / or an electromagnetic sensor, particularly a distance sensor. For example, it may be a Hall effect sensor. Using a position measuring device to detect the position of a workpiece has the advantage of improving machine tool accuracy. For example, the grinding wheel of a machine tool grinding unit can be better aligned with the workpiece based on the determined workpiece position, thereby ensuring that the machining allowance of the workpiece is regularly distributed along its periphery and minimizing the workpiece's manufacturing tolerances. In particular, the position measuring device can determine the position of the workpiece to ensure that no collision occurs when the grinding wheel contacts the teeth of the workpiece.

[0043] According to the present invention, the aforementioned objective is also achieved by a machine tool for grinding teeth on workpieces, particularly for hard finishing workpieces with pre-formed teeth, such as gear blanks. For this purpose, such a machine tool includes a housing, a grinding apparatus, and a device according to the above embodiment. According to the present invention, the grinding apparatus is arranged on the housing and is designed for grinding workpieces. The housing of the machine tool forms the base of the device according to the above embodiment.

[0044] The machine tool of the present invention has the advantage of allowing for faster loading and unloading of workpieces by means of its device. Furthermore, or in addition, the carrier rotatable about a first axis of rotation improves the accessibility of the various components of the machine tool. Its advantage lies in the fact that the machine tool of the present invention is easier to maintain.

[0045] In a first exemplary embodiment, the machine tool includes a dressing device arranged on a carrier and a workpiece spindle arranged on the carrier. The dressing device may be designed to dress grinding tools of a grinding apparatus, particularly for contouring and / or regrinding. Preferably, the dressing device is arranged radially offset on the carrier relative to a first axis of rotation. This results in the dressing device pivoting about the first axis of rotation, for example, when the carrier rotates about it. The dressing device may be movably arranged on the carrier, particularly for translational and / or rotational movements. Preferably, the dressing device is arranged on the carrier on the side of the carrier furthest from the workpiece spindle. For example, the dressing device is arranged on the carrier at a position 180° offset from the first axis of rotation and the workpiece spindle.

[0046] The workpiece spindle is preferably designed to drive the rotation of a workpiece arranged on it. The gripping device is advantageously designed to load and unload the workpiece from the workpiece spindle. The workpiece spindle can rotate about a third rotation axis, and more particularly, can rotate about a third rotation axis. The third rotation axis is preferably offset parallel to the first rotation axis. The effect is that when the carrier, for example, rotates about the first rotation axis, the workpiece spindle will pivot about the first rotation axis.

[0047] The carrier can rotate about a first rotation axis, allowing it to rotate back and forth between a grinding position and a maintenance position. In the grinding position, the workpiece spindle preferably faces the grinding apparatus. Advantageously, this allows the grinding apparatus to machine the workpiece on the workpiece spindle in the grinding position. In the maintenance position, the dressing device can face the grinding apparatus. Advantageously, this allows the dressing device to maintain the grinding wheels of the grinding apparatus in the maintenance position. The machine tool of the first embodiment is advantageous because it is easy for the user to operate and maintain.

[0048] As a supplementary or alternative solution, the workpiece spindle and / or gripping device can be more easily (especially unobstructed) accessed by the user in an accessible location. The accessibility of the carrier can be equated with the maintenance location of the carrier.

[0049] In one exemplary embodiment, in addition to the dressing device, the machine tool also has a copying device. The copying device can be designed to copy, particularly pre-copy, the grinding wheel of the grinding machine. For example, the copying device may have a rotating cutting edge over which the grinding wheel can rotate to form a tooth profile on the grinding wheel. The copying device is preferably arranged on a gripping device. Advantageously, the copying device faces the grinding machine when the carrier is in the maintenance position. Specifically, this allows for very rapid sequential pre-copying of the grinding wheel, followed by dressing. Preferably, the pre-copying is performed by the copying device, and the dressing is performed by the dressing device. Its advantage is that the time spent on grinding wheel maintenance can be minimized.

[0050] According to the present invention, the aforementioned objective is also achieved by a method using the apparatus described above. The apparatus preferably comprises a first gripping arm, a second gripping arm, and a third gripping arm. The method of loading and unloading workpieces for machine tools using this apparatus has the advantage of enabling faster loading and unloading of workpieces, and particularly faster changing of multiple workpieces.

[0051] Methods for loading and unloading workpieces for a machine tool may include an initial loading process, i.e., the first loading of workpieces into the machine tool. During the initial loading process, a first gripping arm and a second gripping arm preferably pivot relative to each other about a second axis of rotation, such that the first gripping arm and the second gripping arm are in a gripping position relative to each other to grip a first workpiece. The first gripping arm and the second gripping arm may, for example, grip the first workpiece at a pick-up position. After the first gripping arm and the second gripping arm grip the first workpiece, the gripping device can be moved axially along the second axis of rotation. For example, this can be useful if the first workpiece needs to be lifted after gripping it. In another step of the initial loading process, the first gripping arm and the second gripping arm pivot synchronously about the second axis of rotation. During synchronous pivoting, the first gripping arm and the second gripping arm remain in the gripping position relative to each other. This causes the first workpiece to also pivot about the second axis of rotation. This allows the first workpiece to be transported from the pick-up position to the loading position. The loading position is preferably located on or at the workpiece spindle.

[0052] After the first and second gripping arms pivot synchronously, the gripping device can selectively move axially along the second rotation axis. This has the advantage of allowing, for example, the first workpiece to be lowered onto or placed on the workpiece spindle. In the final step of the initial loading process, the first and second gripping arms pivot relative to each other about the second rotation axis, such that they are in a released position relative to each other. In this way, the workpiece is released from the loading position by the first and second gripping arms. Preferably, the first and second gripping arms are spaced apart from each other in the final step of the initial loading process so that the first workpiece can be machined by the grinding device at the loading position, particularly without obstruction.

[0053] In an exemplary embodiment, this method includes a workpiece replacement process. Preferably, the workpiece replacement process involves replacing the first workpiece with a second workpiece. For example, the first workpiece may have already been ground by a machine tool and, in particular, may be located on the workpiece spindle. For instance, in order to subsequently grind the second workpiece, the first workpiece on the workpiece spindle must be replaced by, or replaced with, the second workpiece.

[0054] At the start of the workpiece changeover process, the second workpiece can be gripped by the second and third gripping arms. For this purpose, the second and third gripping arms can pivot relative to each other about a second axis of rotation, such that the second and third gripping arms are in a gripping position relative to each other. In another step of the workpiece changeover process, the first and second gripping arms can pivot relative to each other about a second axis of rotation, such that the first and second gripping arms switch from a released position to a gripping position relative to each other. For example, the first and second gripping arms can grip the first workpiece by switching from the released position to the gripping position.

[0055] Preferably, the third gripping arm pivots about the second rotation axis so that it synchronously follows the second gripping arm. This advantageously keeps the second and third gripping arms in a gripping position relative to each other, and the second workpiece moves in tandem with the second and third gripping arms.

[0056] This method allows for the direct provision of a second workpiece alongside the first. Advantageously, this means that when actually changing between two workpieces, the gripping arm only needs to pivot slightly, for example, within a range of <90°, preferably <45°. This small pivot range ensures quick and efficient workpiece changeover.

[0057] Once the first workpiece has been gripped by the first and second gripping arms, and the second workpiece has been gripped by the second and third gripping arms, a transport process can be performed during workpiece changeover, which will be described in detail below. During transport, the first, second, and third gripping arms preferably pivot synchronously about a second rotation axis, so that the first and second workpieces also pivot synchronously about the second rotation axis. During transport, the second gripping arm is preferably used on both sides. That is, the second gripping arm contacts the first workpiece on its side facing the first gripping arm and the second workpiece on its side facing the third gripping arm. Advantageously, this means that as many workpieces as possible can be transported simultaneously with as few gripping arms as possible. Its advantage is that workpiece transport is particularly efficient.

[0058] In another step of the workpiece changing process, the second workpiece can then be released from the loading position. For this purpose, the second and third gripping arms pivot relative to each other about a second rotation axis, so that the second and third gripping arms are in a released position relative to each other. By the synchronous pivoting of the first and second gripping arms about the second rotation axis, the first workpiece can be transported to the placement position. Subsequently, the first and second gripping arms can pivot relative to each other about the second rotation axis, so that the first and second gripping arms are in a released position relative to each other, and the first workpiece is released from the placement position.

[0059] A preferred method for loading and unloading machine tools includes multiple workpiece changeover processes. Specifically, this method may include a first workpiece changeover process and a second workpiece changeover process. For example, during the first workpiece changeover process, a second workpiece may replace the first workpiece. This process has been described above.

[0060] During the first workpiece changeover, the second gripping arm preferably pivots around the second rotation axis in the first pivot direction. Specifically, during the transport process in the first workpiece changeover, the second gripping arm pivots around the second rotation axis in the first pivot direction.

[0061] Similar to the first workpiece change process, the second workpiece can be replaced by a third workpiece during the second workpiece change process. During the second workpiece change process, the second gripping arm can pivot about a second rotation axis in a second pivot direction. The second pivot direction is preferably opposite to the first pivot direction. In other words, the first and second pivot directions are preferably opposite. For example, during the transport process in the second workpiece change process, the second gripping arm pivots about the second rotation axis in the second pivot direction. This advantageously allows for loading and unloading of the machine tool (especially the workpiece spindle) from different directions (e.g., from the left and right sides). The advantage of this method is that it ensures faster and more efficient workpiece changes.

[0062] In an exemplary improvement of one of the two embodiments of the method for loading and unloading machine tools described above, the second and third gripping arms can pivot relative to each other about a second rotation axis during the second workpiece change, such that the second and third gripping arms switch from a release position to a gripping position relative to each other. For example, the second and third gripping arms can grip the second workpiece by switching from the release position to the gripping position. Alternatively, the second and third gripping arms can pivot relative to each other about a second rotation axis during the workpiece change, such that the second and third gripping arms switch from a gripping position to a release position relative to each other, for example, to release the workpiece between the second and third gripping arms.

[0063] Regardless of whether the second and third gripping arms switch from the release position to the gripping position, or vice versa, the first gripping arm preferably pivots about the second rotation axis during the second workpiece change process, so that the first gripping arm synchronously follows the second gripping arm. This advantageously has the following effect: for example, when the first and second gripping arms are in the gripping position relative to each other, and a third workpiece is placed between the first and second gripping arms, the third workpiece will move with the second gripping arm. The advantage of this method is that the second workpiece change process helps ensure rapid and efficient workpiece changeover.

[0064] In another exemplary embodiment, this method includes a transport process. This transport process, already described in the above embodiments, can be configured to transport two workpieces simultaneously. This can be particularly advantageous during workpiece changeover. During the transport process, for example, the first workpiece can be moved away, particularly away from the loading position, while the second workpiece can be transported into place, particularly to the loading position. During the transport process, for example, the first workpiece can be moved away from the workpiece spindle, while the second workpiece is moved towards the workpiece spindle. During the transport process, the first workpiece is preferably positioned between the first and second gripping arms, wherein the first and second gripping arms are in a gripping position relative to each other. Furthermore, the second workpiece can be positioned between the second and third gripping arms, wherein the second and third gripping arms are in a gripping position relative to each other. In other words, during the transport process, the second gripping arm is preferably positioned between the first and second workpieces. To transport the workpieces, the first, second, and third gripping arms can pivot synchronously about a second rotation axis. Workpieces are transported simultaneously in this manner, particularly by pivoting them simultaneously about the second rotation axis. Simple Explanation of the Diagram

[0065] Figure 1 is a perspective view of an embodiment of a grinding machine, which has a device for loading and unloading materials. Figure 2 is a perspective view of the gripping device of an embodiment of the device for loading and unloading materials for a grinding machine shown in Figure 1. Figure 3 is a partial cross-sectional view of the gripping device in Figure 2. Figure 4 is another cross-sectional view of the gripping device according to Figure 2. Figure 5 is a schematic diagram of a second embodiment of the gripping device. Figure 6 is a top view of the embodiment in Figure 1 during the initial loading process. Figure 7 is a top view of the embodiment in Figure 1 at the start of the workpiece change process. Figure 8 is a top view of the embodiment in Figure 1 when the transport process begins during the workpiece change. Figure 9 is a top view of the embodiment in Figure 1 when it is in a maintenance position or in a position where an operator places a workpiece. Figure 10 is a partial cross-sectional view of one embodiment of Figure 1. Figure 11 is a perspective view of a portion of another embodiment of a grinding machine, which has a device for loading and unloading materials. Implementation

[0066] According to the present invention, the different exemplary features described above can be combined with each other, provided that it is technically reasonable and suitable. Further features, advantages, and embodiments of the invention can be derived from the following description and drawings of the embodiments. FIG1 shows a perspective view of an embodiment of a grinding machine 30, which has a device 1 for loading and unloading materials for the grinding machine 30, particularly for loading and unloading workpieces 40 for the grinding machine 30. In the illustrated embodiment, the grinding machine 30 is a gear grinding machine 30. The gear grinding machine 30 is designed to process the workpiece 40, particularly to grind it. The workpiece 40 may be a workpiece 40 with pre-formed teeth, particularly a gear blank 40.

[0067] The grinding machine 30 shown here is only schematic and includes a grinding device 32 having an abrasive wheel 33 for grinding the workpiece 40. The abrasive wheel 33 is, for example, a worm wheel 33. The grinding device 32 is arranged on a housing 31. The housing 31 also forms a base 2 for the loading and unloading device 1 for the grinding machine 30.

[0068] The device 1 for loading and unloading materials for the grinding machine 30 has a carrier 3 and a gripping device 11.

[0069] The carrier 3 is connected to the base 2 and is rotatable relative to the base 2 about a vertical first rotation axis D1. The carrier tower 4 of the carrier 3 is radially offset relative to the first rotation axis D1 and has an outer surface 5. In the illustrated embodiment, a vertical second rotation axis D2 extends in the carrier tower 4 and is offset parallel to the first rotation axis D1.

[0070] The carrier 3 is equipped with a dressing device 6. The dressing device 6 is designed to dress the grinding wheel 33 of the grinding device 32, particularly for contouring and / or regrinding. Furthermore, the carrier 3 is also equipped with a workpiece spindle 7. The workpiece spindle 7 is rotatable relative to the carrier about a third rotation axis D3. The workpiece spindle 7 is designed to rotate about the third rotation axis D3, particularly when a workpiece 40 is mounted on the workpiece spindle 7.

[0071] The gripping device 11 is arranged on the carrier 3, particularly on the carrier tower 4, and is movable along the outer surface 5 of the carrier tower 4. In other words, the gripping device 11 is axially movable along the second rotation axis D2. The gripping device 11 is designed to grip and release the workpiece 40.

[0072] The gripping device 11 has a first gripping arm 13, a second gripping arm 14, and a third gripping arm 15. Each gripping arm 13, 14, and 15 can pivot independently of the other gripping arms 13, 14, and 15 about a second rotation axis D2. The order of the gripping arms 13, 14, and 15 is determined circumferentially on the second rotation axis D2 such that the second gripping arm 14 is always positioned between the first gripping arm 13 and the third gripping arm 15.

[0073] Each of the first and third gripping arms 13 and 15 is provided with a gripping member 21. In the illustrated embodiment, the middle second gripping arm 14 is provided with two gripping members 21. The gripping members 21 are arranged on the gripping arms 13, 14, and 15 such that the gripping member 21 of any outer gripping arm 13 or 15 can always cooperate with the gripping member 21 of the middle gripping arm 14 facing that gripping member. Each gripping member 21 includes an upper part and a lower part, wherein the corresponding gripping arm 13, 14, and 15 is arranged between its upper and lower parts. Preferably, the upper and lower parts of each gripping member 21 are connected to each other by a pin extending through the corresponding gripping arm 13, 14, and 15. The gripping members 21 are fixedly connected to the gripping arms 13, 14, and 15. Preferably, the connection between the gripping member 21 and the gripping arms 13, 14, and 15 is detachable so that the gripping member 21 can be replaced. The upper and lower parts of the gripping member 21 are both formed with a gripping claw with a circular inner contour, and the diameter of the inner contour is matched with the diameter of the workpiece 40 to be gripped.

[0074] Each gripping arm 13, 14, 15 is disposed on a drive ring 16, 17, 18 (see also Figure 2). In the illustrated embodiment, the first gripping arm 13 is disposed on the first drive ring 16, the second gripping arm 14 is disposed on the second drive ring 17, and the third gripping arm 15 is disposed on the third drive ring 18. Each drive ring 16, 17, 18 is independently rotatable about a second rotation axis D2. The connection system between the drive rings 16, 17, 18 and the corresponding gripping arms 13, 14, 15 is designed such that when the drive rings 16, 17, 18 rotate about the second rotation axis D2, the corresponding gripping arms 13, 14, 15 pivot about the second rotation axis D2.

[0075] The gripping device 11 includes a drive unit 23, which is designed to independently drive the gripping arms 13, 14, and 15. The drive unit 23 has multiple drive members 24, 25, and 26, each driving a drive ring 16, 17, and 18, specifically a first drive member 24, a second drive member 25, and a third drive member 26.

[0076] Figure 2 shows a perspective view of the gripping device 11 of the embodiment in Figure 1.

[0077] As shown in Figure 2, the workpiece 40 is gripped by the first gripping arm 13 and the second gripping arm 14. For this purpose, the first gripping arm 13 and the second gripping arm 14 have been pivoted about the second rotation axis D2 so that the first gripping arm 13 and the second gripping arm 14 are in a gripping position relative to each other.

[0078] The workpiece 40 comes into contact with gripping members 21 arranged on the first gripping arm 13 and the second gripping arm 14. The gripping members 21 collectively apply a clamping force to the workpiece 40. Furthermore, each gripping member 21 has a protrusion 22, which is illustrated on the gripping member 21 of the third gripping arm 15. The gripping member 21 can hold the workpiece with the protrusion 22.

[0079] The second gripping arm 14 and the third gripping arm 15 are in the released position relative to each other, as shown in Figure 2. In the released position, the second gripping arm 14 and the third gripping arm 15 are far apart, especially in the circumferential direction of the second rotation axis D2, such that no workpiece can be gripped by the second gripping arm 14 and the third gripping arm 15. The distance between the second gripping arm 14 and the third gripping arm 15 is selected so that no clamping force can be applied to the workpiece through the gripping member 21. Furthermore, the distance between the second gripping arm 14 and the third gripping arm 15 is selected so that the protrusion 22 cannot support the workpiece.

[0080] The drive rings 16, 17, and 18 are arranged side-by-side, or rather, stacked vertically, relative to the second rotation axis D2. The base 12 of the gripping device 11 axially restricts the drive rings 16, 17, and 18.

[0081] Figure 3 shows a partial vertical sectional view of the gripping device 11, illustrating the layout of the drive rings 16, 17, and 18. The sectional view in Figure 3 is chosen so that the section is parallel to the second axis of rotation D2.

[0082] Drive rings 16, 17, and 18 are mounted to rotate relative to each other via rolling bearings 19. The two outer drive rings, specifically the first drive ring 16 and the third drive ring 18, are supported axially on the base 12 of the gripping device 11 via rolling bearings 19. The bearing structure shown in Figure 3 functions similarly to an angular contact ball bearing, thereby transmitting axial and radial forces through the rolling bearings 19.

[0083] In the embodiments described herein, drive rings 16, 17, and 18 are annular. In alternative embodiments, drive rings 16, 17, and 18 may be semi-annular or partially annular.

[0084] As shown in Figure 3, taking the second gripping arm 14 and the second drive ring 17 as an example, the gripping arms 13, 14, and 15 on the drive ring 16 are arranged radially outward on the drive rings 16, 17, and 18.

[0085] Each drive ring 16, 17, 18 has an internal tooth 20 on its inner surface.

[0086] Figure 4 illustrates, for example, a portion of a horizontal sectional view of the gripping device 11, showing the internal teeth 20 of the first drive ring 16. For better understanding, the sectional view in Figure 4 is chosen to be a section orthogonal to the second rotation axis D2 of the gripping device 11.

[0087] As previously described, each gripping arm 13, 14, 15 is driven by a corresponding drive ring 16, 17, 18. The drive rings 16, 17, 18 are themselves driven by drive members 24, 25, 26 of the drive unit 23, respectively. The cross-sectional view shown in Figure 4 illustrates the drive shaft of the first drive member 24, which is connected to the spur gear 27 in a non-rotatable manner. The spur gear 27 is rotatably mounted in the base 12 of the gripping device 11. The spur gear 27 has external teeth 28 that mesh with the internal teeth 20 of the first drive ring 16. This meshing has the effect that when the spur gear 27 is driven by the drive member 24, the rotational movement of the spur gear 27 causes the drive ring 16 to rotate about the second rotation axis D2. Correspondingly, the first gripping arm 13, arranged on the first drive ring 16, also pivots about the second rotation axis D2.

[0088] The driving of drive ring 16, as illustrated by example in Figure 4, also applies to all other drive rings 17 and 18. Accordingly, the second drive ring 17 is driven by the second drive member 25, and the third drive ring 18 is driven by the third drive member 26.

[0089] Figure 5 shows a second embodiment of the gripping device 11. The structure of the gripping device 11 in the second embodiment is basically the same as that in the first embodiment.

[0090] The only difference between the two embodiments of the gripping device 11 is that the gripping device 11 in the second embodiment has a position measuring device 9.

[0091] The position measuring device 9 includes two sensors 10a arranged on the second gripping arm 14. The sensors 10a are arranged on the second gripping arm 14 such that when the second gripping arm 14 is in a gripping position with the first gripping arm 13 and / or the third gripping arm 15, and a workpiece 40 is placed between the relevant gripping arms, the sensors 10a face a workpiece 40 respectively.

[0092] In the position shown in Figure 5, the second gripping arm 14 and the first gripping arm 13 are in the gripping position, with a workpiece 40 placed between the second gripping arm 14 and the first gripping arm 13. The second gripping arm 14 and the third gripping arm 15 are in the released position relative to each other, therefore, no workpiece 40 is placed between the second gripping arm 14 and the third gripping arm 15.

[0093] The sensor 10a can be an optical sensor and / or an electromagnetic sensor, particularly a Hall sensor. The sensor 10a is preferably designed to determine the position of the corresponding workpiece 40, particularly the rotational angular position of the corresponding workpiece 40. The position determination can be based on the tooth surface of the workpiece 40.

[0094] For example, the first gripping arm 13 and the second gripping arm 14 can move from the gripping position shown in Figure 5 to the release position, so that the workpiece 40 can be driven to rotate by the workpiece spindle 7, but the sensor 10a remains facing the workpiece 40. In this way, the sensor 10a can detect the teeth of the workpiece 40 passing through the sensor 10a when rotating.

[0095] The position determining device 9 further includes a sensor 10b, which is designed to determine the position of each gripping arm 13, 14, 15 and / or the position of the workpiece 40 located between each gripping arm 13, 14, 15. Alternatively or supplementarily, the sensor 10b may also be designed to determine the position of the workpiece 40 arranged in front of the sensor 10b, particularly the rotational angular position of the workpiece 40 arranged in front of the sensor 10b. The sensor 10b may be an optical sensor and / or an electromagnetic sensor 10b.

[0096] As an alternative, the positions of the gripping arms 13, 14, and 15 can be determined using drive components 24, 25, and 26. This is particularly advantageous when the drive components 24, 25, and 26 are synchronous motors. For example, the positions of the gripping arms 13, 14, and 15 can be determined based on the number of rotation steps performed by the synchronous motors 24, 25, and 26.

[0097] Figure 6 shows a top view of the grinding machine 30 of Figure 1. For the specific construction of the grinding machine 30, the specific construction of the device 1 for loading and unloading the grinding machine 30, and especially the specific construction of the gripping device 11, refer to the above-described embodiment. Unlike Figure 1, Figure 6 shows a fourth rotation axis D4. The grinding wheel 33 of the grinding device 32 is designed to rotate around the fourth rotation axis D4.

[0098] In the view shown in Figure 6, the device 1 for loading and unloading the grinding machine 30 is in the initial loading process. That is, in Figure 6, the device 1 is in the state that occurs when the device 1 loads the grinding machine 30 for the first time in a processing cycle. This can be seen from the fact that there is no workpiece on the workpiece spindle 7 and no workpiece between the second gripping arm 14 and the third gripping arm 15. The second gripping arm 14 and the third gripping arm 15 are in the released position relative to each other. The first gripping arm 13 and the second gripping arm 14 are in the gripping position relative to each other and have jointly gripped, for example, the first workpiece 40 provided on a belt conveyor.

[0099] After the position shown in Figure 6, the first workpiece 40 is transported onto the workpiece spindle 7. To lift the first workpiece 40, the gripping device 11 can be axially displaced along the second rotation axis D2 toward the observer. In addition, the first gripping arm 13 and the second gripping arm 14 pivot the first workpiece 40 clockwise around the second rotation axis D2 until the first workpiece 40 is above the workpiece spindle 7; in the illustrated example, the pivot angle is 180°. During this process, the first gripping arm 13 and the second gripping arm 14 pivot synchronously around the second rotation axis D2. Then, the gripping device 11 can selectively move again along the second rotation axis D2, particularly axially away from the observer, to place the first workpiece 40 onto the workpiece spindle 7. In order to complete the initial loading process, the first gripping arm 13 and the second gripping arm 14 are each pivoted about the second rotation axis D2, such that the first gripping arm 13 and the second gripping arm 14 are in the release position relative to each other and release the first workpiece 40, especially on the workpiece spindle 7.

[0100] Figure 7 shows the grinding machine 30, particularly the apparatus 1, after the initial loading process is complete. This can be seen from the fact that the first workpiece 40 is located on the workpiece spindle 7. Furthermore, the first gripping arm 13 and the second gripping arm 14 are in the released position relative to each other. The first gripping arm 13 and the second gripping arm 14 are far apart, allowing the first workpiece 40 to be machined unimpeded by the grinding apparatus 32, particularly by the grinding wheel 33. The first gripping arm 13 and the second gripping arm 14 are pivoted relative to each other about a second rotation axis, such that the distance between the first gripping arm 13 and the second gripping arm 14 is greater than the axial width of the grinding wheel 33. The second gripping arm 14 and the third gripping arm 15 are also in the released position relative to each other.

[0101] The second workpiece 41 is provided by conveyor belt 34. During workpiece changeover, the second gripping arm 14 and the third gripping arm 15 pivot about the second rotation axis D2 from the position shown in FIG. 7, such that the second gripping arm 14 and the third gripping arm 15 are in a gripping position relative to each other, simultaneously gripping the second workpiece 41. After the second workpiece 41 is gripped by the second gripping arm 14 and the third gripping arm 15, the gripping device 11 can selectively move along the second rotation axis D2, particularly axially toward the observer, in order to lift the second workpiece 41.

[0102] During workpiece changeover, the second gripping arm 14 and the third gripping arm 15 pivot the second workpiece 41 clockwise around the second rotation axis D2 until the second workpiece is positioned circumferentially next to the first workpiece 40. For this purpose, the second gripping arm 14 and the third gripping arm 15 pivot synchronously around the second rotation axis D2. It can be envisioned that the gripping device 11 moves selectively along the second rotation axis D2, particularly axially away from the observer.

[0103] The machining of the first workpiece 40 can continue during these steps.

[0104] As shown in Figure 8, the device 1, particularly the gripping device 11, is positioned at an intermediate position during the workpiece change process. To reach this position, after processing the workpiece 40, the first gripping arm 13 and the second gripping arm 14 pivot relative to each other around the second rotation axis D2, placing them in a gripping position and gripping the first workpiece 40. The third gripping arm 15 pivots around the second rotation axis D2 synchronously with the second gripping arm 14, specifically following the pivoting motion of the second gripping arm 14. In other words, the second gripping arm 14 and the third gripping arm 15 remain in the gripping position unaffected by the movement of the second gripping arm 14. The second workpiece 41 is held between the second gripping arm 14 and the third gripping arm 15.

[0105] During the workpiece changeover process, the transport process is preferably carried out after the position shown in Figure 8. During transport, specifically, the first workpiece 40 is transported away from the workpiece spindle 7, and the second workpiece 41 is transported to the workpiece spindle 7. The first workpiece 40 is preferably held between the first gripping arm 13 and the second gripping arm 14 during transport. The same applies to the second workpiece 41 between the second gripping arm 14 and the third gripping arm 15. In other words, during transport, the first gripping arm 13 and the second gripping arm 14 are held in a gripping position relative to each other. Similarly, the second gripping arm 14 and the third gripping arm 15 are also held in a gripping position relative to each other during transport. To transport workpieces 40 and 41, the first gripping arm 13, the second gripping arm 14, and the third gripping arm 15 can pivot synchronously about the second rotation axis D2. The first gripping arm 13, the second gripping arm 14, and the third gripping arm 15 preferably pivot clockwise synchronously about the second rotation axis D2. Workpieces 40 and 41 are transported simultaneously in this manner, and in particular, they are simultaneously pivoted clockwise around the second rotation axis D2.

[0106] Figure 9 shows a grinding machine 30 in a maintenance position, particularly the device 1 for loading and unloading materials onto and off the grinding machine 30. In the illustrated embodiment, the maintenance channel of the grinding machine 30 is located at the lower edge of Figures 6 to 9, through which the user can access the components of the grinding machine 30. This channel can also be used to manually load workpieces onto the grinding machine 30.

[0107] To move device 1 to the maintenance position, carrier 3 is rotated 90° clockwise about the first rotation axis D1 relative to housing 31 or base 2. This causes gripping device 11 to pivot 90° clockwise about the first rotation axis D1. Gripping device 11 is thus positioned in the maintenance channel and accessible to the user. Carrier 3 can also be rotated further about the first rotation axis D1 to, for example, position dressing device 6 in the maintenance channel, or make it accessible to the user. Alternatively or supplementarily, carrier 3 can be rotated about the first rotation axis D1 to position workpiece spindle 7 in the maintenance channel, or make it accessible to the user.

[0108] Figure 10 shows a cross-sectional view of a portion of the grinding machine 30 (i.e., a portion of the device 1). As shown in the view of Figure 10, the dressing device 6 is arranged at the lower end of the carrier tower 4 of the carrier 3. The dressing device 6 can translate in the direction of motion R indicated by the arrow. That is, the dressing device 6 can move radially outward and radially inward relative to the carrier 3 or relative to a first rotation axis D1 (not shown in Figure 10). Its translational motion is orthogonal to the first rotation axis D1.

[0109] In addition, the dressing device can pivot around the pivot axis S. The pivot axis S is arranged parallel to and spaced apart from the first rotation axis D1. Since the dressing device 6 is capable of translational and rotational movements, it can be precisely aligned with the grinding wheel 33 in the maintenance position. Therefore, the dressing of the grinding wheel 33 can be particularly precise.

[0110] Figure 11 shows a perspective view of a portion of another embodiment of a grinding machine 30, which has a device 1 for loading and unloading materials into and out of the grinding machine 30. The only difference between the other embodiment shown in Figure 11 and the above embodiment is that the device 1 in this other embodiment has a contouring device 29.

[0111] The contouring device 29 is fixed to the base 12 of the gripping device 11. Preferably, the contouring device 29 is arranged on the gripping device 11 such that it faces the grinding wheel 33 of the grinding device 32 when the device 1 (particularly the carrier 3, not shown in FIG. 11) is in the maintenance position. FIG. 11 shows the device 1 in the maintenance position. To contour the grinding wheel 33, the grinding wheel 33 is rotated about the fourth rotation axis D4 and moved toward the contouring device 29. As a result, the contouring device 29 removes material from the grinding wheel 33, thereby contouring the grinding wheel 33.

[0112] 1: (Loading and unloading) device 2: Base 3: Carrier 4: Carrier Tower 5: Outer surface 6: Repairing equipment 7: Workpiece spindle 8: Centering device; tailstock 9: Position measuring device 10a: Sensor 10b: Sensor 11: Gripping device 12: Matrix 13: (First) Gripping Arm 14: (Second) Gripping Arm 15: (Third) Gripping Arm 16: (First) Drive ring 17: (Second) Drive ring 18: (Third) Drive ring 19: Rolling bearings 20: Internal teeth 21: Grab Components 22: Protrusion 23: Drive unit 24: (First) Drive component; synchronous motor 25: (Second) Drive component; synchronous motor 26: (Third) Drive component; synchronous motor 27: Spur Gear 28: External teeth 29: Copying device 30: Grinding machine; gear grinding machine; machine tool; hard finishing machine 31: Chassis 32: Grinding device 33: Abrasives; worm gear grinding wheels 34: Conveyor belt 40: (First) workpiece; gear blank 41: (Second) workpiece D 1: First axis of rotation D 2: First axis of rotation D 3: Third axis of rotation D 4: Fourth axis of rotation R: Direction of motion S: Pivot axis

Claims

1. An apparatus for loading and unloading workpieces for a machine tool for machining teeth, the machine tool (30) being particularly a hard finishing machine (30), the apparatus (1) comprising: A base (2), a carrier (3), arranged on the base (2) and rotatable relative to the base (2) about a first rotation axis (D1), and a gripping device (11), arranged on the carrier (3), for gripping and releasing the workpieces (40, 41), wherein, The gripping device (11) has at least two gripping arms (13, 14, 15) that are independently pivotable about a second rotation axis (D2) and that are pivotable relative to each other about the second rotation axis (D2) such that the gripping arms (13, 14, 15) are positioned relative to each other in a gripping position for gripping the workpiece (40, 41) and a releasing position for releasing the workpiece (40, 41), and that the gripping arms (13, 14, 15) are pivotable synchronously about the second rotation axis (D2) at least in the gripping position.

2. The apparatus as claimed in claim 1, wherein, The carrier (3) is provided with a workpiece spindle (7) for driving the workpiece (40, 41) to rotate, and the gripping device (11) is designed to load and unload the workpiece (40, 41) onto the workpiece spindle (7).

3. The apparatus as claimed in claim 1 or 2, wherein, The gripping device (11) can move axially along the second rotation axis (D2).

4. The apparatus as claimed in claim 1 or 2, wherein, The second rotation axis (D2) is offset parallel to the first rotation axis (D1).

5. The apparatus as claimed in claim 1 or 2, wherein, The gripping device (11) is designed to grip or release workpieces (40, 41) without being affected by the position and / or rotational motion of the carrier (3).

6. The apparatus as claimed in claim 1 or 2, wherein, The gripping device (11) includes a drive unit (23) which is designed to independently drive the gripping arms (13, 14, 15).

7. The apparatus as claimed in claim 6, wherein, The drive unit (23) includes multiple drive components (24, 25, 26), preferably multiple synchronous motors (24, 25, 26), wherein each drive component (24, 25, 26) and preferably each synchronous motor (24, 25, 26) corresponds to a gripping arm (13, 14, 15).

8. The apparatus as claimed in claim 7, wherein, Each gripping arm (13, 14, 15) is arranged on a drive ring (16, 17, 18) that can rotate about the second rotation axis (D2), wherein when the corresponding drive ring (16, 17, 18) rotates about the second rotation axis (D2), its corresponding gripping arm (13, 14, 15) pivots about the second rotation axis (D2).

9. The apparatus as claimed in claim 8, wherein, Each drive ring (16, 17, 18) has an internal tooth (20), and each drive member (24, 25, 26) has a spur gear (27) with an external tooth (28), wherein the external tooth (28) meshes with the internal tooth (20) of the corresponding drive ring (16, 17, 18) to drive the gripping arm (13, 14, 15) arranged on the drive ring (16, 17, 18).

10. The apparatus as claimed in claim 1 or 2, wherein, Each of the gripping arms (13, 14, 15) is provided with at least one gripping member (21), and the gripping member (21) is designed to apply a clamping force to the workpiece (40, 41) at the gripping position, and / or has a protrusion (22) for supporting the workpiece (40, 41).

11. The apparatus as claimed in claim 1 or 2, wherein, The gripping device (11) is designed to grip multiple workpieces (40, 41) simultaneously.

12. The apparatus of claim 1 or 2, wherein, The gripping device (11) has a first gripping arm (13), a second gripping arm (14) and a third gripping arm (15), wherein the second gripping arm (14) is arranged circumferentially between the first gripping arm (13) and the third gripping arm (15) on the second rotating shaft (D2).

13. The apparatus of claim 12, wherein, The gripping device (11) is designed such that the second gripping arm (14) can be in a gripping position or a release position relative to the first gripping arm (13), and can be in a gripping position or a release position relative to the third gripping arm (15).

14. The apparatus of claim 1 or 2, wherein, The carrier (3) can rotate around the first rotating axis (D1), so that the carrier (3) can rotate back and forth between an operating position and a maintenance position. In the operating position, the machine tool (30) can load and unload the workpiece (40, 41) by means of the device. In the maintenance position, the machine tool (30) and / or the device (1) can be maintained and / or manually loaded.

15. The apparatus of claim 1 or 2, wherein, The carrier (3) has a vertically arranged carrier tower (4), wherein the gripping device (11) is arranged on one of the outer surfaces (5) of the carrier tower (4).

16. The apparatus of claim 1 or 2, wherein, A dressing device (6) is provided on the carrier (3), which is used to dress one of the grinding wheels (33) of the machine tool (30).

17. The apparatus of claim 16, wherein, The trimming device (6) can move relative to the carrier (3), preferably by translation and / or rotation.

18. The apparatus of claim 1 or 2, wherein, A contouring device (29) is provided on the carrier (3), which is used to pre-contour one of the grinding wheels (33) of the machine tool (30).

19. The apparatus of claim 1 or 2, wherein, The device (1) has a centering device (8), preferably a tailstock (8), which is used to center the workpiece (40, 41), preferably to center the workpiece (40, 41) on the spindle (7) of the workpiece in claim 2.

20. The apparatus of claim 1 or 2, wherein, The device (1) has a position measuring device (9) for measuring the position of the workpiece (40, 41), particularly the position of at least one tooth gap of the workpiece (40, 41), wherein the position measuring device includes at least one sensor (10).

21. A machine tool for grinding teeth on a workpiece (40, 41), preferably for hard finishing workpieces (40, 41) with pre-formed teeth, the machine tool (30) comprising: A housing (31), a grinding device (32), arranged on the housing (31) for grinding the workpiece (40, 41), such as any of claims 1 to 20 for mounting the workpiece (40, 41) on the machine tool (30), wherein the housing (31) of the machine tool (30) is formed as the base (2) of the device (1).

22. The machine tool as described in claim 21, wherein, A dressing device (6) is provided on the carrier (3) for dressing one of the grinding tools (33) of the grinding device (32). A workpiece spindle (7) is provided on the carrier (3) for driving the workpiece (40, 41) to rotate around a third rotation axis (D3). The carrier (3) can rotate around the first rotation axis (D1), so that the carrier (3) can rotate back and forth between a grinding position and a maintenance position. In the grinding position, the workpiece spindle (7) faces the grinding device (32), and in the maintenance position, the dressing device (6) faces the grinding device (32).

23. The machine tool as requested in item 21 or 22, wherein, The carrier (3) can rotate about the first rotation axis (D1) so that the carrier (3) is in an accessible position where the user can approach the workpiece spindle (7).

24. A method for loading and unloading at least one workpiece for a machine tool, comprising using the apparatus (1) of any one of claims 1 to 20, wherein, The device (1) has a first gripping arm (13), a second gripping arm (14) and a third gripping arm (15).

25. As in request item 24, wherein, During the workpiece changeover, the first gripping arm (13) and the second gripping arm (14) pivot relative to each other around the second rotation axis (D2), such that the first gripping arm (13) and the second gripping arm (14) switch from the release position to the gripping position or from the gripping position to the release position relative to each other. The third gripping arm (15) pivots around the second rotation axis (D2) so that the third gripping arm (15) synchronously follows the second gripping arm (14).

26. As in request item 25, wherein, The workpiece replacement process is a first workpiece replacement process, and the second gripping arm (14) pivots around the second rotation axis (D2) in a first pivot direction during the first workpiece replacement process, while the second gripping arm (14) pivots around the second rotation axis (D2) in a second pivot direction opposite to the first pivot direction during the second workpiece replacement process.

27. As in request item 26, wherein, During the second workpiece change process, the second gripping arm (14) and the third gripping arm (15) are pivoted relative to each other about the second rotation axis (D2), so that the second gripping arm (14) and the third gripping arm (15) switch from the release position to the gripping position or from the gripping position to the release position relative to each other. The first gripping arm (13) is pivoted about the second rotation axis (D2) so that the first gripping arm (13) synchronously follows the second gripping arm (14).

28. The method of any one of claims 24 to 27, wherein, During a transport process, a first workpiece (40) is placed between the first gripping arm (13) and the second gripping arm (14), wherein the first gripping arm (13) and the second gripping arm (14) are in a gripping position relative to each other, and a second workpiece (41) is placed between the second gripping arm (14) and the third gripping arm (15), wherein the second gripping arm (14) and the third gripping arm (15) are in a gripping position relative to each other, and the first gripping arm (13), the second gripping arm (14) and the third gripping arm (15) pivot synchronously about the second rotation axis (D2) to transport the first workpiece (40) and the second workpiece (41), in particular to pivot them about the second rotation axis (D2).

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