Patent Application
20060260381
The invention relates to an apparatus for transporting workpieces through processing stations of a press, in particular a transfer press or the like.
If the production of a workpiece necessitates a number of processing sequences, such as cutting and forming, then, for cost-effective production, the necessary individual operations are carried out in a so-called transfer press. The number of tools then corresponds to the number of operating stages which are necessary for producing the workpieces.
The presses contain transporting apparatuses which transport the workpieces from one work station to the next. The transporting apparatus may be configured as a 2-way transfer means or 3-way transfer means, the movement axes of the transporting means thereby being defined. Provided for a 2-way transfer means are supporting rails which run through the press on both sides and on which crossmembers equipped with suction devices or the like are fastened for workpiece-transporting purposes, these crossmembers executing simultaneous horizontal and vertical movements.
In the case of a 3-way transfer means, the supporting rails are designed as so-called gripper rails which, in addition to horizontal and vertical movements, also execute a transverse movement and grip the workpiece by means of gripper elements in order to transport the workpiece from one processing stage to the next. The 3-way or gripper-type transfer means is preferably used in practice for transporting flexurally rigid sheet-metal parts which can be gripped from the outside.
Driving action along the 3 axes can take place directly, via cam plates and levers, by means of the press drive, or each movement axis is provided with a dedicated drive. A 3-way transfer means with dedicated drives in each case is disclosed in U.S. Pat. No. 4,887,446. The vertical movement and the closing movement, in the direction transverse to that in which workpieces run through the press, take place by means of electric motors or hydraulic cylinders. An electric linear drive is proposed for executing the horizontal movement of the supporting rails.
No further details are given in U.S. '446 regarding the linear drive and, in particular, the lengths of the primary and secondary parts. Similarly, U.S. '446 does not disclose the gripper-rail change which is necessary for retooling purposes.
An arrangement for coupling and uncoupling gripper-rail parts is described in detail in DE 36 36 010. An arrangement based on the principle of a swivel-type tensioning clamp is proposed as the connecting element or gripper-rail lock. In addition to the complex configuration which is necessary, the task, in particular, of achieving a clearance between the gripper-rail parts, for the changeover operation, requires considerable outlay.
Instead of the horizontal movement of the supporting rails, this movement can also be produced by virtue of transporting carriages on the supporting rails.
An object of the invention is to design, for a press and in particular for a transfer press with 2-way or 3-way transfer means, a linear drive for the horizontal movement such that the linear drive is of cost-effective design and, even while meeting stringent power-related requirements, provides for a compact construction. In addition, during tool-changing operations, the linear drive is intended to allow the gripper rails to be exchanged straightforwardly.
The present invention is based on the idea of providing two linear drives per supporting rail for the horizontal movement. These linear drives are arranged such that the supporting rail can be changed straightforwardly. For this purpose, the linear motors are located essentially at the outer ends of the supporting rail. These outer ends are separate from the supporting rail which is to be changed over and are connected to the latter in a releasable manner via supporting-rail locks. The supporting-rail locks are likewise located in separate endpieces, and merely a clamping head engages in the supporting rail which is to be changed over. For the changeover operation, the connection is released and, by means of the linear motors, the endpieces are moved horizontally apart from one another by a defined distance, this resulting in a straightforward tool-changing operation. This movement sequence advantageously allows the supporting-rail lock to be designed in a very straightforward form. In the case of a preferably used 3-way transfer means, the supporting rail is designed as a gripper rail.
For the actual retooling operation, the press bed is designed as a sliding table, on which the tool is located. It is also the case that all the component-dependent accessories which are necessary for workpiece-transporting purposes are likewise set down on the sliding table and moved out of the press.
A new tool is clamped in place, and the component-dependent accessories are arranged, on a sliding table located outside the press. Following changeover of the sliding tables, the press is converted, fully automatically, to the new production and the supporting-rail parts which have been exchanged are also clamped in position by the supporting-rail locks. For this purpose, the linear drives move the supporting-rail endpieces, with the supporting-rail locks located therein, in the direction of the supporting rail to the extent where the clamping heads can engage in the mount provided in the supporting rail. The supporting-rail locks clamp together the supporting rail and the endpieces, and the supporting rail is also thereby fixed to the linear drive.
The use of linear drives advantageously fulfills the object of the invention. Relatively recent developments make available highly dynamic drives with quick displacement sequences. Since these drives operate without any wear, a constant high level of positioning accuracy throughout the service life is ensured.
A compact and low-cost configuration is achieved on account of the high power density of the linear drives and the fact that there are two drives per supporting rail and the drives are integrated directly at the supporting-rail ends.
A further advantage of using two drives is that the operational reliability increases since, in the event of one drive failing, the second drive moves the supporting rail, and in particular the grippers on a gripper rail, out of the collision zone.
The invention is used particularly advantageously in the case of a 3-way transfer means. Further advantages and details of the invention can be gathered from the description and from the figures showing an exemplary embodiment.
The following embodiment of the present invention describes a 3-way transfer means with gripper-rail drive.
The linear drives are designated 16 and 17 and comprise a primary part 18, 19 and a secondary part 20, 21. The primary part 18, 19 is arranged on the closing boxes 8, 9. The secondary part 20 is connected to the gripper-rail endpiece 11, while the secondary part 21 is divided, and is fastened both on the gripper rail 10 and on the gripper-rail endpiece 12. In the case of the 3-way transfer means, the linear drives 16, 17 produce the horizontal movement of the workpieces in the transporting direction 22 and the return displacement counter to the transporting direction 22.
It is easy to recognize the short and compact construction of the drives as a result of the latter being in divided form, in accordance with the present invention.
While providing for an extremely short construction and a short horizontal displacement path, dividing up the secondary part 21 into a part which is fastened on the gripper rail 10 and a part which is located on the gripper-rail endpiece 12 makes it possible to provide for the clearance which is necessary for gripper-rail-changing purposes.
The gripper-rail endpiece 11 is guided and retained in the mount 23 by the linear guides 24.
The invention is not restricted to the exemplary embodiment illustrated and described. It also covers all specialist developments within the context of the idea according to the invention.
It is thus also possible to use just one linear drive in order to change the gripper rail. The following schematic sequence is then necessary:
Of course, the apparatus according to the invention of the exemplary embodiment can also be transferred, in principle, to a 2-way transfer means with suction-bar workpiece transportation.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2004 005 046.5 | Jan 2004 | DE | national |
This application is a continuation of International Application No. PCT/EP2005/000800, having an international filing date of Jan. 27, 2005, which designated the United States, and claims the benefit of German Application No. 10 2004 005 046.5, filed Jan. 30, 2004, the entireties of which are incorporated herein by reference.
| Number | Date | Country | |
|---|---|---|---|
| Parent | PCT/EP05/00800 | Jan 2005 | US |
| Child | 11490926 | Jul 2006 | US |
