DEVICE FOR SWIVELING, TURNING AND CHANGING WORKPALLETS, AS WELL AS HORIZONTAL MACHINING CENTER

Description

[0001] The invention relates to a device according to the preamble of patent claim 1 and a horizontal machining center according to the preamble of patent claim 10.

[0002] Such devices, known as pallet changing automation, are well known and are used on horizontal machining centers [www.bavius-technologie.com "5-axis machining centers for high-performance machining", type HBZ AeroCell; technical information sheet from 11 / 2018.], for example, for aircraft parts, to manipulate and change workpieces or workpiece pallets carrying blanks. The swivel arms are swiveled synchronously via motors and gears between a position parallel to the floor and an almost vertical position with one or two pallets docked back-to-back to the pallet carriers. During swiveling, the pallets, or a single pallet, are rotated around the turning axis by motors and gears arranged on the swivel arms. They are then brought into the horizontal machining center in the correct position and placed on a floor-side storage unit. The pallets are then docked or undocked onto or from the floor.from the pallet carriers. Hydraulic motors or electric motors can be used as motors. The transmissions typically comprise planetary gears. Since the swivel arms themselves can be swiveled separately and are swiveled synchronously via the motor control system, with the control system determining the respective positions of the swivel arms and the pallet carriers using complex sensors and measuring devices, a malfunction in the drive of, for example, a swivel arm can lead to safety-critical situations when handling the pallet or pallets.

[0003] In a machining center known from DE 10 2017 217 878 ​​A1, which forms the basis for the preamble of claim 1, pallets carrying workpieces are held between two parallel swivel arms, which are driven synchronously to each other by electric motors and gears on both sides.

[0004] In a device known from CN 109261832 A, mounting supports for workpieces that can be pivoted parallel to one another are driven synchronously by electric motors and gears arranged on the outer sides of the mounting supports.

[0005] In a machine center with machine tools known from EP 0 913 227 A2, a loading device is used for manipulation in the work area of ​​the machine center. This device has two synchronously pivoting parallel pivot arms that are non-rotatably coupled to each other by a shaft. Both pivot arms are driven on only one side of the loading device via electric motors and gears located there.

[0006] In a positioning device for workpieces in processing robots known from WO 2014 / 058397 A1, two indexing arms are rotatable parallel to each other around an indexing axis and are coupled to each other in a rotationally fixed manner by a connecting shaft. The indexing arms carry rotatable flanges for holding workpieces. Both indexing arms are driven by a single servo motor and gear units located on only one side of the device.

[0007] The invention is based on the object of improving a device of the type mentioned above and a horizontal machining center in such a way that critical operating situations are excluded in the event of a malfunction on one side.

[0008] The stated problem is solved with the features of claim 1 and the features of claim 10.

[0009] Since the two swivel arms are coupled together in a rotationally fixed manner, in the event of a malfunction on one side, the drive of the other swivel arm takes over the task on the malfunctioning side, ensuring that the swivel arms are kept parallel despite the one-sided malfunction. Electric motors and combined swivel-angle and planetary gear units offer ideal conditions for easily bearing the additional load on the malfunctioning side, swiveling both swivel arms in parallel and holding them in their respective positions without mutual offset. For the rotationally fixed coupling of the two swivel arms, a main shaft is provided which bridges the distance between the swivel arms and is parallel to the swivel axis, coupling the swivel arms together. According to Wikipedia, a main shaft is a drive shaft of a machine that transmits a rotary motion from a drive motor to another point on the machine and / or takes up the load at the other point.

[0010] In a suitable embodiment, the main shaft is a tube anchored to both pivot arms, preferably to the inner flanks of the pivot arms facing each other, which, due to the tube cross-section, offers a sufficiently high section modulus to transfer the load of the disturbed side in the event of a one-sided disturbance.

[0011] Due to the rotationally fixed coupling of the two swivel arms, it is advisable for the two swivel electric motors, which can preferably be asynchronous motors, to be operated in master / slave mode to swivel the swivel arms around the swivel axis. In other words, the master electric motor specifies the motion sequence, which is controlled synchronously by the slave electric motor.

[0012] In a practical embodiment, the tube is positioned eccentrically upwards and / or offset from the free end of the swivel arm when the swivel arm is positioned near the floor. Despite a large-diameter tube with a high section modulus, this offset creates a free space around a docked or docking workpiece pallet that can be used by personnel.

[0013] In a structurally simple embodiment, the device comprises a bearing block for each swivel arm, which has at least one mounting bracket and floor supports. The swivel arm is pivotally mounted in the bearing block and to which the planetary gear of the combined swivel-angle planetary gear is mounted. The relatively high loads generated during handling with one or two pallets are transferred to the floor, for example, via the bearing block.

[0014] The planetary gear of the combined reversing angle planetary gear is conveniently mounted on an outer flank of the swivel arm so that there is sufficient space between the swivel arms and the pallet carriers for docking and undocking the respective pallet.

[0015] It is advisable if the respective swivel electric motor is installed approximately vertically and the respective reversing electric motor is installed approximately parallel to the extension of the swivel arm.

[0016] Specifically due to the use of electric motors and the rotationally fixed coupling of the swivel arms, complex and error-prone sensor or measuring devices for monitoring movements can be omitted. The swivel arms can be mechanically brought to a fixed stop around the swivel axis and the pallet carriers or pallets around the turning axis, and can be stopped in the respective end position by tapping the motor power. The motor power can be tapped via a voltage or current increase and provides precise information about when the respective fixed stop has been reached.

[0017] The device is usefully a pre-assembled unit that can be removed and attached to the horizontal machining center using the mounting brackets, i.e. a so-called pallet changing automation.

[0018] The horizontal machining center equipped with the device is characterized by increased operational reliability and simpler control, since a critical operating situation is avoided despite a one-sided malfunction in a swivel arm.

[0019] An embodiment of the subject matter of the invention is explained with reference to the drawing. It shows: Fig. 1 a perspective view of a horizontal machining center with an attached device for swiveling, turning and changing workpiece pallets, and Fig. 2 an enlarged section of Fig. 1 .

[0020] Fig. 1 and 2 show a device V for swiveling, turning and changing workpiece pallets P1, P2, as a prefabricated unit E (pallet changing automation) mounted or attached to a horizontal machining center H, for example for machining workpieces W for the aircraft industry.

[0021] Fig. 1 shows an overall view of the horizontal machining center H, in whose machining front 2 a pallet P1 is already clamped in a vertical position for machining. In front of the horizontal machining center H, a floor-side pallet storage 20 is provided, on which a second pallet P2 rests in a horizontal position, on whose upward-facing setup side a workpiece W or several workpieces are positioned, which are fixed, for example, by negative pressure, to the setup side of the pallet P2. Depending on whether the second pallet P2 is removed from the machining position during a pallet change and prepared for removal, or is brought into the machining position to be exchanged for the first pallet P1, the second pallet P2 carries a machined workpiece W or a blank.

[0022] The device V has two bearing block cheeks 6, which are mounted, for example, with mounting brackets 3 on the front 2 of the horizontal machining center H. Each bearing block cheek 6 can have at least one floor support 7. In each bearing block cheek 6, a pivot arm 4 projecting on one side is rotatably mounted, which pivot arm 4 is pivoted by means of a drive unit 8 about a pivot axis 5 substantially parallel to the floor between the lowered and Fig. 1 and 2 shown position and a substantially vertical position pivoted upwards towards the front 2 of the horizontal machining center H. The drive 8 comprises a vertically mounted electric motor 9 and a combined angular and planetary gear with an angular gear 10 and a planetary gear 11 flanged externally to the support bracket cheek 6. The device V can also be anchored to the floor only in front of the center H.

[0023] The two pivot arms 4, which can be pivoted synchronously and parallel to one another and at a distance from one another, are coupled in a rotationally fixed manner via a main shaft 12 that bridges the distance between the pivot arms 4. In the embodiment shown, the main shaft 12 is a tube 13, the two ends of which are anchored to mutually facing flanks 14 of the pivot arms 4. Optionally, the tube 13 or the main shaft 12 is positioned eccentrically offset from the pivot axis 5, such that the tube 13, in the positions of the pivot arms 4 shown close to the ground, is offset upwards and / or towards the front 2 of the horizontal machining center H relative to the pivot axis 5. This offset creates free space around the second pallet P2, which can be used, for example, by personnel when working on the second pallet P2.

[0024] At each of the free swivel arm ends, a block-shaped pallet carrier 16 is rotatable about a turning axis 15 parallel to the swivel axis 5, which can be turned, for example, over 180° via an electric motor 19, an angular gear 18 and a planetary gear 17 flanged to the swivel arm 4. The second pallet P2 is already docked to both pallet carriers 16, for example via not shown rams of the pallet carriers 16, which are inserted into receiving bores on the pallet end faces by pneumatic or hydraulic cylinder drives 21, 22 ( Fig. 2 ) are retractable. The electric motor 19 and the angular gear 18 are installed approximately parallel to the direction of extension of the swivel arm 4 on its outer flank 23. The drives 21, 22 for the stamps can be operated in pairs independently of each other. The second pallet P2 is Fig. 2 The upper drives 21 are docked, while the lower drives 22 are not activated in this operating phase, but are only used later for pallet changing or docking the first pallet P1. Thus, a single pallet P2 can be docked with the pallet carriers 16, as shown, or (not shown) both pallets P1, P2, which are then docked back to back in the pallet carriers 16. To fix the respective workpiece on the pallet P1, P2, the Fig. 1 and 2 The setup side of the second pallet P2 shown, for example, has suction openings distributed over a large area through which the workpiece is subjected to a vacuum and secured (not shown). The supply of the pallet P2 with negative pressure and other working media, such as compressed air, hydraulics, or electrical signals, is carried out via the pivot arms 4 to the pallet supports 16, and with regard to the negative pressure, from these, for example, into the pallet P2.

[0025] The electric motors 9 of the drives 8 and the combined angular and planetary gears are designed to be so powerful that in the event of a malfunction in the drive 8 on one side, the other drive 8 can absorb the additional load and solely provide the actual pivoting, so that the pivot arms 4 move synchronously or are kept synchronous and parallel despite the malfunction. This is an important safety aspect, since such a malfunction could lead to extremely critical operating situations without the rotationally fixed coupling of the pivot arms 4.

[0026] Due to the rotationally fixed coupling of the swivel arms 4, it is expedient to control the swivel movements in a mode in which one electric motor 9 acts as the master, while the other electric motor 9 on the opposite side acts as the slave. The slave electric motor 9 is electronically controlled according to the movement of the master electric motor 9 so that, in normal operation, the two electric motors 9 swivel the swivel arms 4 with one or two pallets P1, P2 synchronously and in parallel at all times.

[0027] The vertical shaft 12 could also be designed as a solid profile. In the case of the tube shown as vertical shaft 12 in the Fig. 1 and 2 End plates of the tube 13 are, for example, screwed or welded to the mutually facing flanks 14 of the swivel arms 4.

[0028] A pallet change, for example, proceeds as follows: The workpiece on the first pallet P1 is currently being processed. The second pallet P2 is loaded with a blank and is already docked to the pallet carriers 16. After the end of processing or during the processing of the workpiece on the pallet P1, which is clamped in the horizontal machining center H and supplied with energy (vacuum, pneumatics, hydraulics and electrical signals) from the horizontal machining center H, the second pallet P2 is pivoted upwards from the horizontal position shown by means of the pivot arms 4 about the pivot axis 5 by, for example, approximately 45°, and then turned counterclockwise about the turning axis 15, so that it is finally moved in the vertical position of the pivot arms 4 with its back against the back of the first pallet P1. The Fig. 2lower drives 22 dock the first pallet P1 onto the pallet carriers 16 before the first pallet P1 is released in the horizontal machining center H. In the process, the energy supplies in the pallet carriers 16 are also connected to the first pallet P1. Subsequently, both pallets P1, P2 are moved away from the front 2 of the horizontal machining center H by lowering the swivel arms 4 by, for example, approximately 45° and turned, so that the setup side of the second pallet P2 now faces the horizontal machining center H, before the swivel arms 4 are swiveled upwards again and bring the second pallet P2 into the processing position, in which the second pallet P2 is now clamped in the horizontal machining center and the pallet carriers 16 are released from the second pallet P2 via the drives 21. By lowering the swivel arms 4 and turning the first pallet P1, it is finally placed on the floor support 20 with the setup side facing upwards.In other words, the device V enables the handling of either only one pallet P1 or P2 or the simultaneous handling of two pallets P1, P2.

[0029] By using the electric motors 9, 19 for pivoting and turning, a complex sensor system or measuring device for monitoring the movements and positions of the pallets P1, P2, the pivot arms 4, and the pallet carriers 16 can be omitted, and each can be moved mechanically to a fixed stop, whereby the power of the electric motors 9, 19 is monitored in such a way that when a fixed stop is reached, the increasing motor current or the changing voltage is tapped and the movement is stopped and the reached position is held.

Claims

1. Device (V) for swiveling, turning and changing workpiece pallets (P1, P2), in particular on a horizontal machining center (H), with two parallel, spaced swivel arms (4) that can each be fitted with a pallet carrier (16) each of which can be swivelled parallel to the other swivel arm (4) by an electric motor (9) and a gear about a substantially horizontal, ground-parallel swivel axis (5), each pallet carrier (16) on the swivel arm (4) parallel to the other pallet carrier (16) can be rotated by an electric motor (19) and a gear about a turning axis (15) parallel to the swivel axis (5), characterized in that the gears are combined bevel planetary gears (10, 11; 17, 18) and the swivel arms (4) which are rotatable by the electric motors (9) about the swivel axis (5) are coupled torque proof to each other via a king shaft (12) which bridges the distance between the swivel arms (4) and is parallel to the swivel axis (5).

2. Device according to claim 1, characterized in that the king shaft (12) is a tube (13) anchored on both swivel arms (4), preferably on mutually facing inner flanks (14) of the swivel arms (4).

3. Device according to claim 1, characterized in that the two electric motors (9), preferably asynchronous motors, can be operated in a master / slave mode, to swivel the swivel arms (4) about the swivel axis (5).

4. Device according to claim 2, characterized in that the tube (13) is positioned eccentrically upwards and / or offset in the direction away from the free end of the swivel arm relative to the swivel axis (5) when the swivel arms (4) are in a position close to the ground.

5. Device according to claim 1, characterized in that the device (V) has a bearing block cheek (6) per swivel arm (4), the bearing block cheek (6) comprising at least one mounting bracket (3) and floor supports (7), in which bearing block cheek (6) the swivel arm (4) is rotatably mounted and on which the planetary gear (11) of the combined swivel bevel planetary gear (10, 11) is mounted on the outside.

6. Device according to claim 1, characterized in that the planetary gear of the combined turning bevel planetary gear (17, 18) is mounted on an outer flank (23) of the swivel arm (4).

7. Device according to claim 5, characterized in that the swivel arm electric motor (9) is installed on the bearing block cheek (6) approximately vertically and the pallet carrier turning electric motor (19) is installed on the swivel arm (4) approximately parallel to the extension of the swivel arm (4).

8. Device according to claim 1, characterized in that the swivel arms (4) about the swivel axis (5) and the pallet carriers (16) about the turning axis (15) can each be moved mechanically to a fixed stop and can be stopped by tapping the motor power.

9. Device according at least one of the preceding claims, characterized in that the device (V) is a pre-assembled structural unit (E) as a so-called pallet change automation that can be removed with the mounting brackets (3) and / or fixed on the floor in front of the horizontal machining center (H).

10. Horizontal machining center (H) for machining workpieces fixed on swivable, turnable and changeable workpiece pallets (P1, P2), characterized in that the horizontal machining center (H) is equipped with a device (V) according to at least one of the claims 1 to 9.