Apparatus for transferring workpieces

Abstract

An apparatus for moving a workpiece in a press installation has a transfer bar extending along a longitudinal bar axis and having longitudinally opposite bar ends. A plurality of tool assemblies on the transfer bar are adapted to grip and hold the workpiece; A pair of stationary frames spaced apart along a Y axis generally parallel to the bar axis are juxtaposed with the bar ends and longitudinally flank the bar. A pair of X slides are each displaceable in a horizontal X direction perpendicular to the Y axis on a respective one of the frames. Respective primary mounts on the X slides each carry a respective end of the bar with the bar longitudinally movable in each of the primary mounts.

Claims

1. An apparatus for moving a workpiece in a press installation, the apparatus comprising: a transfer bar extending along a longitudinal bar axis and having longitudinally opposite bar ends; a plurality of tool assemblies on the transfer bar and adapted to grip and hold the workpiece; a pair of stationary frames spaced apart along a Y axis generally parallel to the bar axis, juxtaposed with the ends, and longitudinally flanking the bar; a pair of X slides each displaceable in a horizontal X direction perpendicular to the Y axis and each on a respective one of the frames; and respective primary mounts on the X slides and each carrying a respective end of the bar with the bar being longitudinally movable at each of its ends in the respective primary mount.

2. The apparatus defined in claim 1, wherein the transfer bar is of fixed length measured from end to end.

3. The apparatus defined in claim 1, further comprising: a pair of Y slides each fixed longitudinally to a respective bar end and slidable along the bar axis in the respective X slide.

4. The apparatus defined in claim 1, wherein each X slide includes a primary X slide movable along the X axis on the respective frame and secondary X slide movable along the X axis on the respective primary X slide, the secondary X slide carrying the respective primary mount.

5. The apparatus defined in claim 4, further comprising: respective primary X drives between each primary X slide and the respective frame; and respective secondary X drives between each secondary X slide and the respective primary X slide.

6. The apparatus defined in claim 1, further comprising: means for shifting the tool assemblies longitudinally along the transfer bar.

7. The apparatus defined in claim 1, wherein the press installation has two presses spaced apart along the Y axis and flanking the transfer apparatus.

8. An apparatus for moving a workpiece in a press installation, the apparatus comprising: a transfer bar extending along a longitudinal bar axis and having longitudinally opposite bar ends; a plurality of tool assemblies on the transfer bar and adapted to grip and hold the workpiece; a pair of stationary frames spaced apart along a Y axis generally parallel to the bar axis, juxtaposed with the ends, and longitudinally flanking the bar; a pair of X slides each displaceable in a horizontal X direction perpendicular to the Y axis and each on a respective one of the frames; respective primary mounts on the X slides and each carrying a respective end of the bar with the bar being longitudinally movable at each of its ends in the respective primary mount; and respective Y actuators connected between the X and Y slides for shifting the bar relative to the X slides along the bar axis.

9. The apparatus defined in claim 8, wherein the Y actuators are pneumatic piston/cylinder units.

10. The apparatus defined in claim 9, further comprising: control means for pressurizing one of the pneumatic piston/cylinder units to urge the bar toward the other pneumatic piston/cylinder unit and simultaneously depressurizing the other unit to allow free movement of the respective bar end in the respective slide.

11. An apparatus for moving a workpiece in a press installation, the apparatus comprising: a transfer bar extending along a longitudinal bar axis and having longitudinally opposite bar ends; a plurality of tool assemblies on the transfer bar and adapted to grip and hold the workpiece; a pair of stationary frames spaced apart along a Y axis generally parallel to the bar axis, juxtaposed with the ends, and longitudinally flanking the bar; a pair of X slides each displaceable in a horizontal X direction perpendicular to the Y axis and each on a respective one of the frames; and respective primary mounts on the X slides and each carrying a respective end of the bar with the bar being longitudinally movable at each of its ends in the respective primary mount, each primary mount end being rotatable about a vertical axis in the respective X slide.

12. The apparatus defined in claim 11, further comprising: respective secondary mounts carried on the primary mounts, rotatable about respective horizontal axes relative to the respective primary mounts, and fitted with the respective bar ends.

13. The apparatus defined in claim 12, further comprising: respective primary drives for rotating the primary mounts about the vertical axes on the respective slides; and respective secondary drives for rotating the secondary mounts about horizontal axes on the respective primary drives.

14. The apparatus defined in claim 12, wherein each of the bars is rotatable about the bar axis in the respective secondary mount.

15. The apparatus defined in claim 12, further comprising: respective couplings at the bar end releasably connecting the respective par ends to the respective secondary mounts.

16. The apparatus defined in claim 15, wherein each coupling includes a socket fitting and a plug fitting, one of the fittings being on the secondary mount and the other fitting on the respective bar end, the one fitting being rotatable about the bar axis on the secondary mount.

Description

BRIEF DESCRIPTION OF THE DRAWING

(1) The above and other objects, features, and advantages will become more readily apparent from the following description, reference being made to the accompanying drawing in which:

(2) FIG. 1 is a simplified side view of a press installation with the transfer apparatus according to the invention;

(3) FIG. 2 is a perspective view of a single transfer apparatus according to the invention between two presses of a pressing stage;

(4) FIG. 3 is a large-scale view of the detail indicated at III in FIG. 2;

(5) FIG. 4 is another view of the object in FIG. 2;

(6) FIG. 5 is an enlarged detail indicated at V in FIG. 4;

(7) FIG. 6 is an enlarged detail indicated at VI in FIG. 4; and

(8) FIG. 7 is an enlarged view of the Y adjuster.

SPECIFIC DESCRIPTION OF THE INVENTION

(9) As seen in the drawing a transfer apparatus T moves workpieces (for example vehicle body parts or panels) in a press installation. FIG. 1 shows a detail of a press installation comprising a press stage having two presses P1 and P2 and the transfer apparatus T, whereas FIGS. 2 through 7 show only the transfer apparatus T and the presses P1 and P2 are not shown in these views. This type of transfer apparatus T is generally employed in a tandem press installation where one transfer apparatus is used for a press stage including two presses as shown at P1 and P2, although each stage could have two such apparatuses T.

(10) The transfer apparatus T includes a transfer bar 1 extending along and defining a horizontal and longitudinal bar axis B (see FIG. 6) generally parallel to a horizontal Y axis and multiple tool assemblies in the form of gripper arms 2 attached to the transfer bar 1. The gripper arms 2 are equipped with grabs here formed by suction devices that can pick up, hold, and release the unillustrated workpiece. The bar 1 can be moved with various degrees of freedom, thereby enabling a wide variety of workpieces to be variably transported. To this end, the transfer apparatus T is here composed of two mirror-symmetrical transfer halves H and the transfer bar 1 that is cardanically suspended between these transfer halves H, with the result that both transfer halves H and the interposed transfer bar 1, which is also known as a suction bar, constitute the complete transfer apparatus T for high-speed transfer.

(11) Each transfer half H includes a vertical frame 3 that essentially forms the base of the respective transfer half H. These vertical frames 3 are preferably fixed to the confronting front faces of the respective presses P1 and P2. Each frame 3 carries vertical guide rails on which a vertically displaceable Z slide 4 of the respective apparatus half H can move along a vertical Z axis. A Z drive 5 is provided on each frame 3 to move the respective Z slide 4 vertically. This Z drive 5 in the illustrated embodiment is fixed to the respective vertical frame 3 and coupled to the respective Z slide 4 by a belt 4.

(12) At least one X slide movable along the X axis is carried on each of the vertically movable Z slides 4. Here, two separate X slides are provided, namely a primary X1 slide 6 and a secondary X2 slide 7. The primary X1 slide can move horizontally along the X1 axis on the vertically movable Z slide 4. To do this, an X1 drive 8 is attached to the Z slide 4 and has a drive gear meshing with a toothed rack 9 fixed on the X1 slide 6. The X2 slide 7 is horizontally movable on the X1 slide 6 along the X2 axis, and the X1 axis and the X2 axis are horizontal and parallel to each other and to the X axis. The X2 slide 7 here can be moved by a separate X2 drive 10 carried on the X1 slide and coupled to the X2 slide 7 by a belt.

(13) The transfer bar 1 is secured at each end to a respective one of the X2 slides 7, so that movement of the transfer bar 1 can be effected in various different axes relative to the X2 slide 7.

(14) What is especially significant to the invention is that the transfer bar 1 can be moved relative to the X2 slide 7 along its longitudinal bar axis Y. For this purpose each end of the transfer bar 1 is connected to a respective Y slide 11 that is movable on the respective X2 slide 7 along the longitudinal bar axis Y. Y actuators 12 are carried on the X2 slides 7 and are coupled to the Y slide 11 connected to the transfer bar 1 to move it along its longitudinal bar axis Y. Another important aspect is that these Y actuators 12 are not servo drives, like the other drives, but instead are piston/cylinder units and specifically here are of an especially advantageous design as pneumatic piston/cylinder units. To this end here the piston rod 12A is connected to the X2 slide 7, while the cylinder 12B is connected to the plate forming the respective Y slide 11, with the result that the Y slide 11 is moved along the Y axis relative to the X2 slide plate 7 by operating cylinder 12. All of these drives and actuatore are operated synchronously by a controller 18 shown schematically in FIG. 2.

(15) Operation of the pneumatic Y actuators 12 first of all plays an important role during engagement and disengagement of the transfer bar 1. This is because the transfer bar 1 is releasably connected to the Y slides 11 by releasable couplings 13. Both bar couplings 13 each have for this purpose a slide-side coupling element 13A and a bar-side coupling element 13B (see detail in FIG. 6), where these two coupling elements 13A, 13B engage each other when pushed together along the longitudinal bar axis B. Here, the socket 13A on the slide 11 fits with the plug 13B on the bar 1. The reverse is also possible, however, where the plug 13B is on the slide 11 and the socket 13A is on the bar 1. In any case it is possible by operating the Y drives 12 to advance the sockets 13A connected thereto along the Bar axis B, thereby engaging and disengaging the transfer bar 1. Provision is furthermore made whereby the coupling elements 13A, 13B can be locked or unlocked. Locking elements 14 that can be operated radially are provided for this purpose, which elements can also be operated pneumatically. The invention utilizes standard couplings here that are also employed, for example for changing robot tools. Only the socket 13A of the coupling 13 is shown in the upper part of FIG. 6. The transfer bar 1 including plug element 13B connected thereto is not shown in upper [art of FIG. 6 but is seen only in the lower part of this view.

(16) In addition to the function of Y drives 12 to effect engagement and disengagement, these Y drives also have an especially important function in compensating for movement of the transfer bar 1. This is because the transfer bar 1 in the shown embodiment is a rigid and non-telescoping bar (when in operation) with a fixed predetermined length. Compensation of motion as transfer halves H move is thus effected in the shown embodiment not by any telescoping motion by the transfer bar 1 itself but by the fact that movement along the Bar axis B is enabled and allowed by both Y drives 12. Very simple pneumatic actuators 12 can be used for this purpose that are not actuated so as to move away but instead are simply moved by pneumatic actuation either to one of their two end positions or are allowed to move freely so that they can move passively between their two end positions without any pneumatic actuation. The one Y drive in the shown embodiment is moved in fixed fashion to an end position acting as a fixed bearing, while the other Y drive can allow free motions along the Bar axis B between the two end positions. This approach allows the transfer bar 1 to follow movement of the two transfer halves H, and specifically whenever the various slides of transfer halves H move in different ways. Various different angular positions, in particular, are possible for the transfer bar 1 without the length of the transfer bar 1 itself changing. This is achieved during operation by the Y drives 12 that essentially operate passively. In addition to the compensating function and the coupling function, these Y drives perform yet another function in connection with adapting the press geometry during initial operation since these Y drives can assist in setting the relevant zero point. Since the system uses a non-telescoping bar and since one of the Y drives creates the fixed side and the other creates the floating side, the tool-assembly center point at different angular positions moves away from the tool-assembly center and this aspect must be taken into account at the tool table or press table. This kind of slight offset is acceptable, however.

(17) It may also be necessary to move or spread individual gripper arms 2 relative to each other or on the suction bar 1. Since the suction bar 1 itself here is of fixed length and cannot telescope, it is useful in this case to provide additional drives on the suction bar 1 that can move the gripper arms 2 along the Bar axis B relative to the suction bar 1. They are not shown in detail in the drawing but they can also be pneumatic drives.

(18) Another especially important aspect is that the transfer bar 1 can be moved relative to the Y slide with various degrees of freedom. To this end the transfer bar 1 is articulated on the Y slide so as to rotate about a bar center axis B and is furthermore also cardanically coupled to the Y slide. Details are shown in FIG. 6. A respective housing 15 is mounted on each Y slide 11 for rotation about a vertical axis C fixed on the respective Y slide 11. The housing 15 is composed for this purpose of an outer housing 15A and inner housing 15B, the outer housing 15A is pivoted on the Y slide 11 for rotation the C axis. The inner housing 15B is rotatable on the outer housing 15A about a horizontal axis A. The transfer bar 1 is in turn rotatably about the B axis on in the inner housing 15B, specifically with coupling 13 being interposed. The rotational motions about the C axis and about the A axis occur passively creating a cardanic suspension. The rotation about the B axis is actively controlled by B drive 16 that can also be a servo drive.

(19) As a result, four servo drives in total are provided for each transfer half Hspecifically, the Z drive, the X1 drive, the X2 drive, and the B drive. This provides the straight-line movement along the X, Y, and Z axis, and rotation about the axes A, B, and C, that is a total of six degrees of freedom. Pneumatic drives 12 for the Y axis performaside from the coupling functiononly a passive function in terms of compensation during operation.

(20) The illustrated transfer apparatus T not only provides very fast transfer, its construction is also very compact and the individual components are readily accessible. An especially important aspect is that all modules are installed above the floor F (FIG. 1) and no components have to be located in the press foundation. The drawing thus shows, for example that even compensation tanks 17, which are provided for hydraulic mass compensation, are disposed on the vertical frames 3 and thus above the press floor F. Reference is thus made here to FIG. 1 that provides a simplified side view of a transfer apparatus installed on the press frame including the compensation tank 17.

(21) The fact that all modules are installed above the floor F, and neither compensation tank 17 nor cylinders and supply lines have to be located in the press foundation, enables maintenance to be simplified and in particular reduces expenditure in terms of time. The components are readily accessible and this in turn shortens the time spent on maintenance work. The space made available thereby is used, for example to automatically move the tool carts into the delivery position during tool changes.

(22) The transfer bar 1 can furthermore be fabricated out of CFRP by the generally known approach. The bar here can be rotated up to 6 about the A axis and by up to 180 about the B axis.