EP0642854A1 - Machine tool with a control device for a functional part - Google Patents

Abstract

On a machine tool, in particular one for bending, punching and embossing, an adjusting device is provided; this adjusting device (20) is intended to correct the position of a functional component (22) of the machine tool relative to a functional-component carrier (10) in at least one position correction direction during the running of the machine. In this arrangement, the adjusting device (20) is designed with a stepper drive (42). <IMAGE>

Description

The invention relates to a workpiece processing machine with an actuating device which is intended and suitable for correcting the position of a functional part of the workpiece processing machine with respect to a functional part carrier during machine operation in at least one position correction direction, the actuating device comprising a stepper drive.

Such an actuating device is known for example from DE 82 00 088 U1. A disadvantage of this control device is the large space requirement.

With regard to the prior art, reference is also made to DE 41 09 795 A1, DE 30 28 834 A1, DE 12 14 071 C2 and US Pat. No. 4,621,517.

The invention has for its object to reduce the space requirement of the actuating device.

To achieve this object, it is proposed according to the invention that the step drive comprises a driver which is adjustable by a switching step on a functional part carrier along a substantially straight-line driver path in opposite directions between a starting position and an end position, and also an actuator which is longitudinal on the functional part carrier an actuator track which is substantially parallel to the driver track is adjustable in opposite directions, and furthermore a driver device which is connected for common movement with the driver along the driver track and is adjustable between a coupling state and a decoupling state, wherein this driver device in the coupling state in each case in one engages from several driving points of the actuator and is uncoupled from the actuator in the uncoupling state and the distance between successive driving points of the actuator in Rich device corresponds to a switching step. In such an embodiment, the The length of a switching step is determined by the movement stroke of the driver along its driver path between the start position and the end position on the one hand and by the distance between successive driving points of the actuator.

A stepper drive designed in this way can be accommodated in a very small space and is therefore particularly suitable for machine tools in the often very cramped space. The adjustment of the functional part in discrete steps is a further advantage, because by specifying a certain number of switching steps an always reproducible position correction can be carried out. This simplifies the control of the actuating device.

When one speaks of a processing machine here, this term is to be understood in a very general sense. In addition to machine tools, processing machines also include assembly machines, packaging machines, cleaning machines, surface treatment machines and printing machines.

In principle, it is possible to design the driver device for the frictional coupling with the actuator. In this case, the length of a switching step can be changed in the simplest way by changing the distance between the start position and the end position of the driver. A flat friction path can then be attached to the actuator, with which the driver device comes into frictional contact. However, an embodiment is preferred in which discrete driving points are provided on the actuator, in which the driving device can interlock positively. In this case, it is not possible to continuously change the switching step length. However, an exact switching step length is specified for this. There is also a change in the switching step length such a solution conceivable. However, the switching step length can only be changed in such a way that it is changed by the distance between two successive driving points of the actuator.

If a positive engagement between the driver device and the actuator is intended, it is recommended that the driver device comprises at least one driver tooth and that a tooth track with a plurality of successive tooth gaps is provided on the actuator, the pitch of which corresponds to a switching step. The driver device can also be designed with a plurality of driver teeth, so that even with small tooth pitch, ie. H. with a small switching step length, sufficient power transmission with low surface pressure is guaranteed.

The driver tooth can be adjusted essentially orthogonally to the driver track and the actuator track between a coupling position and a decoupling position.

In order to facilitate the intervention in the repeated engagement of the driving tooth in the tooth trace and to ensure an inevitable subsequent correction of the actuator position, it is recommended that the driving tooth and / or the tooth gaps of the tooth trace are designed with chamfers.

If the driver can only be adjusted by one switching step between the start and end position, it is nevertheless possible to move the actuator in opposite directions. However, it is then necessary that the start and end positions of the driver are interchanged for the movement of the actuator in opposite directions. This requires a considerable control effort. In addition, the time required for correction is changed by changing the start and end positions the driver extended. A preferred embodiment therefore provides that the driver can be adjusted by a switching step along the driver path between a middle position and two end positions. In this way the control effort for the movement of the driver is reduced and at the same time the correction time is reduced. Reducing the correction time is an essential aspect of the invention, which is achieved by using the stepper drive and is further improved by the special choice of a middle position of the driver between two end positions.

The two end positions of the driver can each be determined by a stop. These stops can be adjustable to extend or shorten the switching step.

The middle position of the driver can be determined by a reset suspension system.

Another essential aspect of the invention is to be seen in the fact that the driver can be adjusted along the driver path by fluid pressure. It should not be ruled out that the driver can also be actuated by other actuating forces, e.g. B. electrical actuating forces is adjusted. The adjustment of the driver by means of fluid pressure has the advantage, however, that the mass and volume of the parts required for the generation of force at the location of the driver can be reduced to a respective minimum. This is of particular importance if - what will be discussed later - the functional part carrier is in turn movable, that is to say, for example, it is designed as a slide for a press. To adjust the driver by means of fluid pressure, it can be provided that the driver is connected to at least one cylinder piston device that is pressurized with fluid. A particularly favorable design in terms of control technology arises when the driver with two in opposite Directions along the driver path effective cylinder piston devices is connected. Such a design is particularly advantageous if the center position of the driver is determined by a return spring system. It is then only necessary for each of the cylinder piston devices to be subjected to fluid pressure on one side.

When talking about fluid pressure, both pneumatic drives and hydraulic drives are considered. Pneumatic drives have the advantage that air pressure sources are already available on many of the processing machines in question, which can be used to drive the driver. Pneumatic drives can be used with great advantage, especially for step drives, where the stride length is defined by stops, since the fluid flow is not required to determine the step length and the compressibility of the gaseous fluid results in a buffer effect when the driver strikes the respective stop.

Hydraulic drives will be used particularly when relatively large forces are required to adjust the actuator. This applies in particular if the actuating device is intended to adjust functional parts at times at which the respective functional part is under mechanical stress due to its respective function.

The fluid pressure can be controlled by a valve device to move the driver back and forth. It is particularly advantageous if the valve device is arranged outside the functional part carrier and is connected to the driver via a flexible line system. This particular advantage is that no additional space is required for the valve device at the driver's location and no additional mass is built up. This is again of particular importance if the functional part carrier itself is designed as a moving part, for. B. as a slide of a small punching and bending press.

The same applies to the actuation of the driver device as to the movement of the driver. B. by electrical controls; however, it is preferred that the driver device is adjustable between the coupling position and the decoupling position by fluid pressure. The reasons for the preferred use of a fluid pressure adjustment of the driver device are in turn a reduction in the space requirement and the mass at the location of the driver. In terms of control technology, there is a favorable solution if the driver device is pretensioned by one driver return spring in one of the two states: coupling state and uncoupling state and can be converted to the other by fluid pressure. This solution also has the advantage of very short switching times, so that the position correction of the respective functional part can be carried out very quickly. This is of great importance in particular in the case of very quickly working machine tools, since it is important in such machine tools that the necessary position correction be carried out quickly in order to avoid production rejects.

The fluid actuation of the driver device can be designed such that at least one driver tooth of the driver device is connected to a cylinder piston device and that the cylinder piston device is assigned a driver return spring. For the activation and deactivation of the fluid pressure necessary to actuate the driver device, of course, a valve device is again required; this too is preferably arranged outside the functional part carrier and connected to it by a flexible line system. This is particularly advantageous again when the functional part carrier undergoes a back and forth movement while the machine is running, because then the sum of the masses which go back and forth with the functional part carrier should be kept as low as possible. An overall particularly simple construction of the stepper drive is obtained if the driver is guided through two cylinder piston devices opposite one another in the direction of the driver path and if a further cylinder piston device belonging to the driver device is arranged in the driver.

It is basically possible to couple the functional part directly to the actuator. However, such a solution will only be considered if relatively coarse position corrections are required. If fine position corrections are required, it is recommended that a reduction gear is provided between the stepper drive and the functional part. Thanks to such a reduction gear, the stride length of the driver and thus the division of the engagement points or teeth on the actuator can be kept relatively coarse and still a very small correction feed of the functional part can be obtained per switching step. If desired, the reduction ratio is variable.

A particularly simple and therefore preferred embodiment is characterized in that a wedge gear is provided between the actuator and the functional part, if desired with a wedge of a variable wedge angle. In particular, such a wedge transmission can be constructed in such a way that the functional part is guided on the functional part carrier in a functional part guide which is essentially orthogonal to the actuator path, and that a wedge surface which is inclined at an acute angle with respect to the actuator path is arranged on the actuator acts on an attack surface of the functional part or of an intermediate member connected to the functional part. The size of the acute angle determines the reduction ratio. If the tooth pitch on the actuator is, for example, 1 mm, that is, if the length of a switching step of the driver is 1 mm, and if the size of the acute angle is, for example, 1.14 ^o , then a feed step for the functional part is 0.02 mm. A self-locking of the reducing wedge gear is then achieved, as is desired. Basically, there is no need to lock the actuator in a position once it has been reached, especially not when an unintentional movement of the actuator along the actuator path is secured by friction of the actuator against the actuator path. Such friction can be secured in the simplest way by constantly pressing the engagement surface against the wedge surface by means of a pretensioning device. However, it should also not be excluded that the driver device is constantly in engagement with the actuator outside of the correction operating phase. In this way, an additional securing of the actuator can be brought about in that phase in which no position correction takes place. In principle, additional locking means for the actuator should not be excluded.

As already indicated, a particularly preferred embodiment consists in that a correction wedge is provided between the functional part and the functional part carrier, which provides support for the functional part on the functional part carrier and is adjustable in a displacement direction that is essentially orthogonal to the position correction direction, by the position of the functional part to correct in relation to the functional part carrier in the position correction direction. The correction wedge on the functional part carrier can be designed such that it can be displaced in the direction of displacement, but is otherwise operationally secured on the functional part carrier.

The displacement direction is preferably orthogonal to the position correction direction, and the displacement wedge can rest against the functional part with a wedge surface that is inclined in relation to the displacement direction with its wedge angle.

According to a particularly preferred embodiment, it is provided that the correction wedge acts on the functional part with a first wedge surface and has an engagement track for the driver device on a back surface inclined against the first wedge surface at the wedge angle.

The actuating device can basically be controlled by human intervention after the need for correction has been identified. So it is conceivable that a controller continuously or intermittently checks the products produced on the respective processing machine and, if necessary, compares them with a standard product and, based on the comparison result, either by means of tables or based on our own knowledge, the control of the actuating device in terms of correcting the standard product takes over.

However, it is preferably provided that the actuating device is controlled by a correction requirement detection device. As a correction need detection device comes, for. B. a line camera in question, which compares a finished part with a standard part and determines deviations. The deviations are then converted in a data processing system into control signals which are passed on to the actuating device.

Even when human influence is switched on, it is conceivable to work with such a line scan camera in such a way that the target contour and the actual contour of, for example, a workpiece obtained by bending treatment are displayed in comparison with any change in scale, and the correction is then carried out until equality of the target contour and actual contour is initiated by hand.

If a correction requirement detection device is provided, its construction and mode of operation can be as follows: upon detection of a correction requirement of a predetermined sign by the correction requirement detection device, the driver is shifted from the initial position to the end position by taking the actuator with the driver device by one switching step. If there is still a need for correction, this process is repeated, if necessary several times, until no further need for correction can be identified. In the event of a repetition of the process, after the driver enters the end position, the driver device returns to the uncoupling state, the driver then returns to the starting position, and finally the driver device returns to the coupling state.

Alternatively, it is provided that the correction requirement detection device is designed to observe the position of at least one measuring point of an already processed product relative to a carrier device of the workpiece processing machine holding the product. In all cases, an opto-electronic observation device is preferably used as part of the correction requirement detection device. The advantage of such an optoelectronic observation device is that it very quickly delivers the signals necessary to carry out the correction. Line scan cameras can be used as opto-electronic observation devices. Because of the particularly small space requirement, combinations of laser light emitters and laser light receivers can preferably also be used. Furthermore, it is conceivable to design shadow images of the respective workpiece using linearly aligned fields of visible light and to observe their shadow edges, for example by means of photodiodes. Finally, it is also possible to determine the orientation of workpiece parts by sending a laser light beam or a visible light beam onto a reflection surface and determining the angular position of the reflected light beam. This angular position then represents a measure of the orientation of the observed surface area of a workpiece and enables the determination of whether the orientation is correct or in need of correction.

In many cases, the functional parts, the position of which is to be corrected, will periodically be subjected to a force load and a force relief while the machine tool is running. It goes without saying that the position correction can be carried out particularly easily and precisely when the functional part has been relieved of force. It is therefore further recommended that the correction processes remain limited to the load relief phases.

These load relief phases can be very short in high-speed machine tools. It is therefore conceivable that a correction cannot be carried out completely during a single force relief phase, but that the correction process is interrupted after a first force relief phase for the duration of the following force relief phase and is resumed after the occurrence of a further force relief phase, possibly in a repeated manner as long as until there is no longer any need for correction.

The functional part can be designed, for example, as a bending, punching or embossing stamp. If it is a stamp for processing small and smallest workpieces that are produced in large numbers, for example electrical contacts, the cycle times are very short (the cycle time corresponds to the production of one workpiece or a group of workpieces). It is precisely in this case that the problem arises of short and shortest relief times, so short that only one switching step or a few switching steps can be carried out during the respective relief phase, despite the rapid reactivity of the actuating device. Then it can It may be necessary to extend a certain correction process over several successive relief phases. In the case of a bending, stamping or embossing stamp as the functional part to be corrected, the relief phase is equivalent to the period from lifting the stamp from a workpiece to be machined to putting the stamp on the next workpiece to be machined.

The functional part can also be a travel limit stop of a periodically moving machine part. The position of such a travel limit stop can be of great importance for the shaping of a workpiece to be machined and therefore needs to be corrected. One example is a travel limit stop for a material feed device, in particular a travel limit stop for a belt or wire feed carriage. Such limit stops for tape or wire feed slides are known for example from DE-OS 39 21 997. On the other hand, tape and wire processing punching and bending machines are known, for example, from DE-OS 41 12 571.

Given the corresponding degree of automation in a system, it is not always necessary and also not always desirable that the observation values supplied by an observation device are used automatically to correct the actuating device. It is also conceivable to have the observation values assessed from time to time by the eye of an operator or to save them on a measurement protocol, so that when predetermined actual value deviations from the respective target values are determined, a correction can be triggered manually, for example in the jog mode of the Stepper. Jog mode should mean that the operator actuates the stepping mechanism from time to time by pressing the pushbutton once or several times until the observation device indicates that the setpoint or setpoints have been reached, or that the setpoints have been reached by measuring them resulting workpieces can be determined by hand.

As already mentioned above, it is possible to change the correction step size by correcting the reduction ratio and in particular the wedge angle. In principle, however, it is also possible to specify the size of the correction steps to be realized in another way, for example by changing the stroke of the driver. This can be done, for example, by adjusting the end stops assigned to the driver in their position.

Fig. 1

das Schema einer Biegevorrichtung mit periodisch angetriebenem Biegewerkzeugträger und einem gegenüber dem Biegewerkzeugträger positionskorrigierbaren Biegestempel;

Fig. 2

das Schema einer Stanzvorrichtung mit periodisch angetriebenem Stanzstempelträger und einem gegenüber dem Stanzstempelträger positionskorrigierbaren Stanzstempel;

Fig. 3

das Schema eines Materialeinzugs bei einer Stanz-, Biege- oder Prägemaschine mit einem korrigierbaren Hubbegrenzungsanschlag für den Einzugsschlitten;

Fig. 4

das Schema eines Stellantriebs zum Verstellen eines Biegestempels gegenüber einem zugehörigen Biegestempelträger;

Fig. 5

das Schema eines abgewandelten Stellantriebs zum Verstellen eines Anschlags, beispielsweise in einer Anordnung gemäß Figur 3;

Fig. 6

eine ergänzte Ansicht auf den Stellantrieb gemäß Figur 5 in Pfeilrichtung VI der Figur 5 und

Fig. 7, 8 und 9

weitere Ausführungsbeispiele von opto-elektronischen Beobachtungseinrichtungen.

The accompanying figures explain the invention. It represent

Fig. 1

the diagram of a bending device with a periodically driven bending tool carrier and a bending punch which can be corrected in relation to the position of the bending tool carrier;

Fig. 2

the diagram of a punching device with periodically driven punch support and a position correctable with respect to the punch support punch;

Fig. 3

the diagram of a material feed in a punching, bending or embossing machine with a correctable stroke limit stop for the feed slide;

Fig. 4

the diagram of an actuator for adjusting a punch against an associated punch holder;

Fig. 5

the diagram of a modified actuator for adjusting a stop, for example in an arrangement according to Figure 3;

Fig. 6

an additional view of the actuator according to Figure 5 in the direction of arrow VI of Figure 5 and

7, 8 and 9

further exemplary embodiments of optoelectronic observation devices.

1 shows a partial area of an automatic bending machine, as is shown, for example, in DE 41 12 571 A1, namely in FIG. 1. Reference is made to position 32 there. A tool slide 10 is guided in a tool slide guide 12 which, for example, is part of a processing unit. The processing unit is screwed onto the frame of a bending machine according to FIG. 1 of DE 41 12 571 A1, which is designed to accommodate a large number of such processing units. The processing unit has a drive shaft 14. On this drive shaft 14, for example, a worm wheel is provided for engagement with a worm shaft according to FIG. 2, position 30 of DE 41 12 571 A1. Furthermore, the drive shaft 14 carries a cam 16 which is intended for the oscillating drive of the tool slide 10 against the action of a spring 18. A functional part, namely a bending punch 22, is attached to the tool slide 10 by means of an actuating device 20 to be described later. The bending punch 22 is intended for bending a strip of material 24 which is shown in dashed lines at 24 'in the bent position. The bending angle is designated by α. The bending tool 22 is shown at 22 'in its lower reversal point, in which the bending state 24' is reached. During the bending, the workpiece 24 to be bent is clamped between a die 26 and a hold-down device 28, the hold-down device 28 being able to move back and forth in the machine cycle between the clamping position and the release position. In this case, a strip material 30 can in each case be advanced by a length corresponding to the length of the workpiece to be extracted by means of a feed and can also be cut off in the machine cycle by means of a cutting punch 32. A feed device for the strip material 30 will be explained in the following.

The bend angle α can be critical for the product to be manufactured, so it is important to maintain this bend angle α with the greatest precision in the entire series of products. On the other hand, a number of influences are conceivable that can lead to a distortion of the angle α:

In continuous operation, wear of the bending die 22 must be expected. However, fluctuations in the material thickness of the delivered strip material 30 must also be expected. Wear of the die can also lead to a distortion of the angle α. It is possible to correct distortions of the angle α by correcting the zero height mark of the top or bottom dead center of the punch 22 in the direction of the double arrow 34, namely in the minus direction, if it turns out that the bending angle α becomes too large, and in the plus direction if it is found that the bending angle α becomes too small. The height mark zero can be corrected by shortening or lengthening the adjusting device 20 in the direction of the double arrow 34.

4, the configuration of the actuating device 20 is shown schematically. 4 shows the basis of a processing unit BE, as shown in DE-OS 41 12 571, for example at point 32. The tool carriage 10 guides the tool carriage 10 on this base unit BE and in turn drives it by means of the cam 16. The bending punch 22 is guided on the tool slide 10 by a bending punch guide 36. The bending punch 22 has an engagement surface 22a at its upper end. This engagement surface 22a is in engagement with a wedge surface 38a of a wedge 38, which in a raceway 40 is transverse to the guide direction of the punch guide 36 is displaceable. The wedge angle is designated β. It is readily apparent that, given the position of the cam 16, for example at the top dead center of the tool slide 10, the position of the bending die 22 can be corrected by moving the wedge 38 along the track 40. It should also be noted here that the raceway 40 of the wedge 38 as well as the bending punch guide 36 are fixed on the tool slide 10. By shifting the wedge 38, the correction of the zero height mark according to FIG. 1 can thus be carried out. A switching step mechanism 42 is provided for shifting the wedge 38. This switching step mechanism 42 comprises a driver 42a which is displaceable on a driver track 42b; the driver track 42b is fixed on the tool slide 10. The driver 42a can be displaced in the direction of the driver track 42b by two pneumatic piston-cylinder units 42c and 42d. Each of the pneumatic piston-cylinder units 42c and 42d has a cylinder 42c1 or 42d1, a piston 42c2 or 42d2 and a return spring 42c3 or 42d3. The pistons 42c2 and 42d2 are connected to the driver 42a by a piston rod 42c4 and 42d4, respectively. The return springs 42c3 and 42d3, as shown in FIG. 4, bias the driver 42a into a central position. The cylinders 42c1 and 42d1 are each connected to a valve device 44 via a flexible line 42c5 or 42d5. Via these lines 42c5 and 42d5, each of the two cylinders 42c1 and 42d1 can be pressurized with compressed air or connected to the atmosphere. If the cylinder 42c1 is pressurized with compressed air and at the same time the cylinder 42d1 is connected to the atmosphere, the driver 42a moves against the action of the return spring 42c3 from the central position according to FIG. 4 to the right up to a stop 42c6. If the cylinder 42d1 is pressurized with compressed air and the cylinder 42c1 is simultaneously connected to the atmosphere, the driver 42a moves against the action of the return spring 42d3 from the central position to the left up to a stop 42d6. The available path of the driver 42a from the central position to each of the stops 42c6 and 42d6 is denoted by Δ.

The driver 42a is designed with a driver cylinder 42a1. This receives a driver piston 42a2. The driver piston 42a2 is connected to a driver 42a7 via a driver piston rod 42a4. The driver piston 42a2 is biased upward by a driver return spring 42a3. The driver cylinder 42a1 is connected to the valve device 44 via a flexible line 42a5. The driver 42a7 faces a tooth trace 38b and can engage in successive tooth gaps in the tooth trace 38b. The distance between successive tooth gaps corresponds to the distance Δ.

In order to shift the wedge 38 to the left by means of the driver 42a, the driver 42a7 is shifted downward by a corresponding circuit in the valve device 44 until engagement with the tooth gap 38b which is opposite each other. A further switch setting in the valve device 44 then shifts the driver 42a to the left up to the stop 42d6. In this case, the wedge 38 is taken to the left by the distance Δ and the bending punch 22 is moved downward, ie in the plus direction. The displacement v results from the relationship

$\text{v = Δtg β.}$

tg β can be understood as the reduction ratio of the wedge gear 38a, 22a. As soon as the driver 42a has reached the stop 42d6, the pressure in the cylinder 42a1 is released by a renewed switchover in the valve device 44, so that the driver 42a7 moves out of the tooth trace 38b. This is followed by another Switching in the valve device 44 of the cylinders 42d1 is depressurized so that the driver 42a returns to the central position shown in FIG. 4. The state according to FIG. 4 is thus reached again. However, the wedge 38 has moved to the left by a switching step Δ, and the bending punch 22 has been moved down by a correction step v.

The angle β is so small, for example between 1 and 3 ^o , that self-locking occurs between the wedge surface 38a and the engagement surface 22a. This means that the wedge 38 cannot move to the right by itself under the action of an upward force on the bending punch 22, that is to say in particular cannot move to the right when the bending punch 22, as shown in FIG. 1, on the workpiece 24 or 24 'acts bending. The fixing of the wedge 38 in the position shown in FIG. 4 can be further supported by locking means not shown. It is also conceivable to use the catch 42a7 to lock the wedge 38 so that, if the wedge 38 is not to be displaced, it engages continuously in the tooth gap that is reached in each case. It is also conceivable to provide a locking member for the wedge 38 which is moved in push-pull to the driver 42a7 and which engages in a tooth gap when the driver 42a7 is withdrawn from engagement with the tooth trace 38b. As a rule, however, it is sufficient to constantly maintain a certain contact pressure between the bending die 22 and the wedge 38, for example by means of a tension spring 46.

It has now been shown how a correction step v of the bending die 22 can be generated in order to correct the bending angle α.

Such a correction step is preferably triggered as a function of the detection of an incorrect angle α on a product of the processing machine. It is conceivable that a control person periodically or continuously measures the resulting products, that is to say curved corner strips 24 ′ here, and if the actual angle α deviates from a target angle α _target, makes a correction by actuating a keyboard. The keyboard can be actuated on the basis of a table from which the control person can determine the respective correction requirement depending on the deviation between the actual angle and the desired angle α. However, the bending angle α is preferably continuously monitored 48 by a line camera. At the same time, a standard workpiece 24 _{target is} observed by a further line camera 50. The observation results from the two line cameras 48 and 50 are compared with one another in a comparator 52 and fed into a data processing system 54. The data processing system 54 forwards a correction signal to the valve device 44 via a line 56. In this way, the setting of the bending punch 22 relative to the tool slide 10 can be continuously corrected.

Instead of an observation by a line scan camera, other electrical or optical observation means can also be provided. It is conceivable to observe the actual configuration or the target configuration using a laser light band measurement. It is also possible to use electrical or mechanical sensors to monitor the target position and / or the actual position. Mechanical sensors can be formed, for example, by mechanical limit switches, the movement of which is converted back into an electrical YES / NO signal. Electrical sensors can be, for example, capacitive or inductive sensors or pressure-dependent electrical resistors that deliver an analog signal about the size of the actual value deviation from the target value.

It is not necessary to determine the target value by constantly observing a workpiece that corresponds to the target values. Rather, it is also possible to record the target workpiece once and to feed the values determined in this way into a computer as target values, so that the actual values can then be compared with these target values continuously or periodically. The measurement and target value determination of a target workpiece can be carried out by the same monitoring device, e.g. Line scan camera, which then observes the workpieces during operation.

It should now be noted that the tool slide 10 constantly executes a movement under the action of the cam 16, which can be very high-frequency with the appropriate performance of the processing machine. In the upwardly retracted position of the bending die 22 according to FIG. 1, the bending die is unloaded. In position 22 'according to FIG. 1, the bending punch is loaded by the bending work. The displacement of the wedge 38 and thus also of the bending die 22 should preferably take place in those phases in which the bending die 22 is unloaded, ie. H. is out of engagement with the workpiece 24, 24 '.

To correct the position of the bending die 22, several correction steps v are now required, depending on the size of the angular deviation between the actual angle and the desired angle α. Thanks to the simple construction and the displacement of the valve device to a location outside the tool slide 10, the adjusting device 20 is indeed freed from unnecessary dimensions, so that it can work at high walking speed. On the other hand, the cycle numbers of modern bending and punching machines are so large that u. It may not be possible to carry out a possibly larger correction during a single relief phase of the bending die 22. In this case, the necessary correction steps can be distributed over several relief phases of the bending die.

As an example, it should be mentioned that the angle β can be, for example, 1.14 ^o and the distance Δ (corresponding to the tooth pitch of the tooth trace 38b) can be 1 mm. Then there is a correction step v of ± 0.02 mm.

It should be noted that a correction can be carried out while the tool slide 10 is running at a constant stroke.

The positions of the stops 42c6 and 42d6 can be adjustable. It is also possible to replace the wedge 38 or only the tooth trace 38b. The size of the switching steps can be changed even if the tooth trace is unchanged, although you are then bound to correction steps, each of which is an integer multiple of v.

The tension spring 46 can be avoided if the bending punch 22 is held in positive engagement with the wedge 38 at its upper end, for example in that there is a tongue and groove connection between the bending punch 22 and the wedge 38.

FIG. 2 shows an arrangement which largely corresponds to FIG. 1. In this arrangement, a stamping punch 122 has replaced a bending punch, the cross section of which is indicated at 122a. Otherwise, analog parts are designated with the same reference numerals as in FIG. 1, increased by the number 100.

The punch 122 is intended to punch holes in a material 130 that is held between a perforated die 126 and a hold-down 128. The punching depth is crucial for the quality of the product. The setting of the punching depth can be carried out according to the scheme which has been explained with reference to FIGS. 1 and 4. It is again possible to correct this by identifying the finished product. But it is also possible to correct the need for correction by other measurements, e.g. B. to determine non-contact length measurements on the product itself or on machine parts.

3 shows another common problem with a punching and bending machine, for which reference is again made to DE-OS 41 12 571 and DE-OS 39 21 997. It has already been pointed out above that the material strip 30 according to FIG. 1 has to be pushed forward in periodically repeated steps into the working area of the bending punch 22. This can be done approximately according to FIG. 3. The material strip 30 from FIG. 1 can be seen again in FIG. 3. This strip of material 30 is now to be advanced periodically to the left in the direction of arrow 58. The material strip 30 comes from a supply reel 60, possibly over a straightening path. The feed takes place by means of a feed slide 62 which is pushed back and forth by a connecting rod drive 64 in the direction of the double arrow 66 on a guide track 68 of the basic construction 70 of the processing machine. A clamping point 74 is provided on the feed carriage 62, which can clamp the material strip 30. For this purpose, a clamping support 74a and a clamping stamp 74b are provided on the feed carriage 62. Another clamping point 76 is formed by a clamping support 76a and a clamping stamp 76b, the clamping support 76a being fixedly attached to the basic construction 70 and the clamping stamp 76b being guided in a clamping stamp guide 76c, which in turn is fixed to the basic construction 70. The material strip 30 is advanced in the direction of the arrow 58 in such a way that the feed carriage 62, which is moved back and forth by the connecting rod drive 64 in the direction of the arrow 66, takes the material strip 30 with it when moving to the left, but with the material strip 30 when moving to the right slides away.

The take-up takes place by clamping the material strip 30 between the clamping support 74a and the clamping plunger 74b; when the feed carriage 62 moves to the right, the clamping plunger 74b is lifted off the clamping support 74a. The material strip 30 is clamped in the clamping point 76 only when the clamping point 74 does not clamp the material strip 30. The exact feed path of the feed carriage 62 is determined by two stops 80 and 81 on the basic construction 70. A spring element 64a is installed in the connecting rod drive 64, which allows the feed carriage 62 to be placed softly on the stops 80 and 81 and also allows the feed carriage 62 to remain in the respective end positions for a certain time. The stop 81 can be designed in exactly the same way as the stop 80 and is only shown in simplified form. The stop 80 is roughly adjustable by a basic setting device 82. This rough adjustment device acts on a stop support 84. The actual stop 80 is supported on this stop support 84 via an actuating device 86, which can be constructed in exactly the same way as the actuating device 20 shown in FIG. 4 and described above 3 while the machine is running without having to make any changes in the connecting rod gear.

It can be readily seen that the actuating device 20 according to FIG. 4 can advantageously be used wherever there is a need to carry out position corrections of a functional part while a processing machine is running.

In the embodiment according to FIGS. 5 and 6, an internal thread nut acting as a stop corresponding to the stop 80 in FIG. 3 is designated 280. This internally threaded nut 280 is displaceable but non-rotatably guided in a guide 211 which is attached to a basic structure 270 corresponding to the basic structure 70 of FIG. 3. A threaded spindle 215 engages in an internally threaded bore 213 of the internally threaded nut 280. The combination of the parts 280 and 215 can also be carried out on the principle of a so-called ball screw. The threaded spindle 215 is axially immovable, but rotatably mounted in a bearing 217 transmitting axial thrust. A pinion 219 is located at the left end of the threaded spindle 215 in FIG. 5. The pinion 219 faces a driver 221 which has a toothing 223. The driver 221 is guided in a linear guide 225. The linear guide 225 is mounted on a platform 227. The platform 227 is guided on the basic structure 270 by a vertical guide 229 so as to be vertically displaceable. The platform 227 is thus adjustable in height, so that the toothing 223 of the driver 221 can be brought into and out of engagement with a toothing 231 of the pinion 219 by adjusting the height of the platform 227. The engagement between the teeth 223 and 231 is made by helical compression springs 235 which push the platform 227 upwards. To release the engagement between the toothings 223 and 231, tension magnets 237 are provided, which pull the platform against the action of the helical compression springs 235 downwards. A design of the tension magnets 237 as lifting magnets and accordingly the compression springs 235 as tension springs is also conceivable and possibly even more advantageous because then a better-defined engagement force can be obtained between the teeth 223 and 231 and during the predominantly disengaged position between the teeth 223 and 231 no continuous current has to flow. The engagement position between the teeth 231 and 223 can be determined by stops 239 and counter-stops 241, so that the teeth themselves are not subjected to pressure. The driver 221 is biased into a central position by helical compression springs 243, which are supported on the one hand on support bearings 245 of the platform 227 and on the other hand engage a contact element 247 which is connected to the driver 221 for common longitudinal movement in the linear guide 225. On the platform 227, bracket magnets 241g 251g and 251d are also attached by means of bracket angles, which with their armatures 253g and 253d are at a distance from the driver 221. By energizing the thrust magnet 251g, the driver can be moved up to an end stop 255d, while by energizing the thrust magnet 251d, the driver 221 can be moved up to an end stop 255g of the linear guide 225. The displacement from the middle position shown in FIG. 6 to the respective end stop 255d or 255g corresponds to the displacement Δ according to FIG. 4. It must also be added that the pitch of the thread of the threaded spindle 215 and the internally threaded bore 213 is so flat that self-locking in the event of axial thrust between the threaded spindle 215 and the threaded nut 280 is guaranteed.

The push magnets 251g, 251d and the pull magnets 237 are controlled by an electrical control unit 257.

The position of the stop 280, ie the nut 280, is set by the machine adjuster to a certain value when the machine starts up, which corresponds to the desired stroke of the feed carriage 62 in FIG. 3. If the feed of the material strip 30 is no longer correct in the course of an operating period of the machine, for example due to wear of the stop surface 259 of the nut 280, a correction can be carried out while the machine is running. The correction can be triggered by a control system, not shown here, for example by monitoring the workpieces by means of an optoelectronic observation system and using this monitoring to obtain actual values which are used to control the electrical control unit 257 in comparison with corresponding target values. The course of a correction process when a deviation between the actual and target values is ascertained is now as follows: during a phase in which the feed slide 62 is out of engagement with the stop surface 259 of the nut 280, the threaded spindle 215 is rotated and thus the nut 280 along it Guide 211 adjusted linearly. To bring about the rotation of the threaded spindle 215, the tension magnets 237 are first de-energized, so that the platform 227 moves up and the two toothings 223 and 231 come into engagement. Once this intervention has been made, depending on the sign of the actual value / setpoint difference, either the solenoid 251g or the solenoid 251d is energized, so that the driver 221 is shifted to the right or left as far as the stop 255d or 255g, in each case by the value Δ (see FIG. 4). This causes a rotation of the threaded spindle 215 and thus an adjustment of the nut 280 by a predetermined path. If the setpoint / actual value comparison has not yet been reached, this process can be repeated by lowering the driver 221 again, by de-energizing both push magnets 251g, 251d the driver returns to the central position determined by the springs 243, the platform 227 thereon is raised again and the teeth 231, 233 are engaged again, with other teeth of the teeth 231 now naturally engaging with the teeth 223. A further rotation of the pinion 219 and thus a renewed displacement of the nut 280 can then be triggered by energizing one of the thrust magnets 251g, 251d.

These processes are basically repeated until the setpoint / actual value comparison has been made. If a return of the feed carriage 62 in the contact position to the stop surface 259 of the nut 280 is to be expected before the setpoint / actual value comparison occurs, the position correction of the nut 280 is interrupted until the feed carriage 62 is removed from the nut 280 in a further machine cycle has taken off again, so that now - again in an unloaded phase of the nut 280 - the correction can be continued until the final adjustment of the setpoint / actual value.

FIG. 7 shows a further embodiment of an opto-electronic observation device. Analog parts are provided with the same reference numerals as in FIG. 1, each increased by the number 300. The leading end of a strip material 330 can again be seen here. This leading end is designated 324 'and has already been bent as shown in FIG. To determine whether the bending angle α is correct, two laser emitters 351, 353 are provided here. These are mounted on the basic construction 370 of the processing machine or on another fixed part of the processing machine, in such a way that, with the correct bending angle α, the laser beams 355 and 357 just pass the bent leading end 324 'and are received by laser beam receivers 359.361. If the angle α is not correct, one or the other laser beam 355, 357 is covered, so that one of the laser beam receivers 359 or 361 does not receive a laser beam. The laser beam receivers 359, 361 are followed by a data processing system 354, which controls a valve device 344, corresponding to the valve device 44 in FIG. 4. If one of the laser beam receivers 359, 361 can no longer receive the associated laser beam, a corresponding correction of the bending tool, which is shown in FIG. 4, is triggered is.

In the embodiment according to FIG. 8, the bent leading end 424 'is illuminated by an illumination source 463 via an optical device 465 with parallel light 467. The illumination source 463 and the optical device 465 can again be attached to the machine frame 470. Furthermore, 470 photocells 471, 473 are attached to the machine frame. These are positioned so that they are just hit by the light field at the correct angle α. If the angle α is not set correctly, one of the photocells 471,473 is no longer struck by light. The photocells 471, 473 are in turn connected to a data processing system 454 which controls the valve device 444. If one of the photocells 471, 473 is darkened, a corresponding correction is triggered by the correction device according to FIG. 4. Analog parts are given the same reference numerals here as in FIG. 4, each increased by the number 400.

FIG. 9 again shows the leading end 524 'of the strip material 530, which is angled by the angle α. A laser emitter 575 is attached to the machine frame 570 and directs a laser beam 577 onto the surface 579 of the angled leading end 524 '. The laser beam 577 is reflected on the surface 579. The reflected beam 581 strikes a semiconductor plate 583 which is populated with a rastered array of photocells 585. These photocells are queried one after the other by means of a multiplexer 587. This determines which photocell 585 is hit by the reflected laser beam 581 at the time of the query. Certain location coordinates are assigned to each photocell 585. The location coordinates of the photocell struck by the reflected beam are fed into the data processing system 554 by the multiplexer 587 and represent a measure of the bending angle α. From the data processing system 554 the valve device 544 is then controlled again and triggers a correction process if the bending angle α does not correspond to the desired value.

The embodiment according to FIG. 4 is to be preferred to that according to FIGS. 5 and 6, because this embodiment is particularly space-saving and therefore also under the very cramped space conditions, e.g. a machine tool that can be accommodated. For the same reason, the optoelectronic observation devices according to FIGS. 7-9 are of particular advantage because the optoelectronic elements shown in these figures can also be accommodated in a very small space.

Claims (42)

Workpiece processing machine with an actuating device which is intended and suitable for correcting the position of a functional part (22) of the workpiece processing machine relative to a functional part carrier (10) during machine operation in at least one position correction direction, the actuating device (20) comprising a step drive (42),
characterized,
that the stepper drive (42) comprises a driver (42a) which is adjustable on a functional part carrier (10) along a substantially rectilinear driver track (42b) in opposite directions between a starting position and an end position by one switching step (Δ) Actuator (38) which can be adjusted in opposite directions on the functional part carrier (10) along an actuator path (40) which is essentially parallel to the driver track (42b), and also a driver device (42a7) which is used for moving together with the driver (42a) is connected along the driver track (42b) and is adjustable between a coupling state and a decoupling state, wherein this driver device (42a7) engages in the coupling state in each case in one of several driving points (at 38b) of the actuator (38) and in the decoupling state of the actuator (38) is uncoupled and the distance between successive entrainment points len (at 38b) of the actuator (38) in the direction of the actuator path (40) corresponds to a switching step (Δ) or a multiple of the switching step (Δ). Workpiece processing machine according to claim 1,
characterized,
that the driver device (42a7) and the driver points (at 38b) of the actuator (38) are designed for mutual positive engagement. Workpiece processing machine according to claim 2,
characterized,
that the driver device (42a7) comprises at least one driver tooth and that on the actuator (38) a tooth trace (38b) is provided with a plurality of successive tooth gaps, the pitch of which corresponds to a switching step (Δ). Workpiece processing machine according to claim 3,
characterized,
that the driver tooth (42a7) is adjustable substantially orthogonal to the driver track (42b) and the actuator track (40) between a coupling position and a decoupling position. Workpiece processing machine according to one of claims 3 and 4,
characterized,
that the driving tooth (42a7) and / or the tooth gaps of the tooth trace (38b) are designed with bevels. Workpiece processing machine according to one of claims 1-5,
characterized,
that the driver (42a) is adjustable between a middle position and two end positions by one switching step (Δ) along the driver track (42b). Workpiece processing machine according to claim 6,
characterized,
that the two end positions of the driver (42a) are each determined by an optionally adjustable stop (42c6,42d6). Workpiece processing machine according to one of claims 6 and 7,
characterized,
that the middle position of the driver (42a) is determined by a return spring system (42c3,42d3). Workpiece processing machine according to one of claims 1-8,
characterized,
that the driver (42a) along the driver track (42b) is adjustable by fluid pressure or electromagnetic means. Workpiece processing machine according to claim 9,
characterized,
that the driver (42a; 221) is operatively connected to at least one fluid piston cylinder device (42c, 42d) or an electromagnet (251d, 251g). Workpiece processing machine according to claim 10,
characterized,
that the driver (42a; 221) is operatively connected to two cylinder piston devices (42c, 42d) or electromagnets (251d, 251g) which operate in opposite directions along the driver track (42b). Workpiece processing machine according to claim 11,
characterized,
that each of the cylinder piston devices (42c, 42d) or electromagnets (251d, 251g) is assigned a return spring (42c3,42d3; 243) which, when the fluid is not under pressure or the electromagnets (251d, 251g) are de-energized, the driver (42a; 221) on the Set middle position. Workpiece processing machine according to one of claims 9-11,
characterized,
that the fluid pressure can be controlled by a valve device (44) or the electromagnets (251d, 251g) by an electrical control device (257). Workpiece processing machine according to claim 13,
characterized,
that the valve device (44) or electrical control device (257) is arranged outside the functional part carrier (10) and is connected to the driver (42a) via a flexible line system (42a5,42c5,42d5). Workpiece processing machine according to one of claims 1-14,
characterized,
that the driver device (42a7) is adjustable by fluid pressure or electromagnetic means between the coupling position and the decoupling position. Workpiece processing machine according to claim 15,
characterized,
that the driver device (42a7) by means of a driver return spring (42a3) in one of the two states: Coupled state and uncoupled state is biased and can be converted into the other by fluid pressure or by electromagnetic means. Workpiece processing machine according to claim 16,
characterized,
that at least one driver tooth of the driver device (42a7) is connected to a cylinder piston device (42a1, 42a2) or an electromagnet and that a driver return spring (42a3) is assigned to the cylinder piston device (42a1, 42a2) or the electromagnet. Workpiece processing machine according to one of claims 1-17,
characterized,
that the fluid pressure or electromagnet acting on the driver device (42a7) is controlled by a valve device (44) or an electrical control device (257) which is arranged outside the functional part carrier (10) and connected to it by a flexible line system (42a5). Workpiece processing machine according to one of claims 1-18,
characterized,
that the driver (42a; 221) is guided by two cylinder piston devices (42c, 42d) or electromagnets (251d, 251g) opposite each other in the direction of the driver track (42b) and that in the driver (42a) another driver device (42a7) Associated cylinder piston device (42a1,42a2) or another electromagnet is arranged. Workpiece processing machine according to one of claims 1-19,
characterized,
that between the stepping drive (42) and the functional part (22) a reduction gear (22a, 38a), which can be changed in its reduction ratio if desired, is provided. Workpiece processing machine according to one of claims 1-20,
characterized,
that between the actuator (38) and the functional part (22) a wedge gear (22a, 38a) - if desired with a wedge (38) of variable wedge angle - is provided. Workpiece processing machine according to claim 21,
characterized,
that the functional part (22) on the functional part carrier (10) is guided in a functional part guide (36) which is substantially orthogonal to the actuator track (40), and that on the actuator (38) an acute angle to the actuator track (40) Wedge surface (38a) is arranged, which acts on an engagement surface (22a) of the functional part (22) or an intermediate member connected to the functional part (22). Workpiece processing machine according to one of claims 20-22,
characterized,
that the reduction gear (22a, 38a) is self-locking. Workpiece processing machine according to one of claims 22 or 23,
characterized,
that the wedge surface (38a) is self-lockingly engaged with the engagement surface (22a), if desired using a pretensioning device (46) which constantly presses the engagement surface (22a) into engagement with the wedge surface (38a). Workpiece processing machine according to one of claims 1-24,
characterized,
that between the functional part (22) and the functional part carrier (10) a correction wedge (38) is provided, which mediates the support of the functional part (22) on the functional part carrier (10) and is adjustable in a substantially orthogonal to the position correction direction of displacement direction correct the position of the functional part (22) relative to the functional part carrier (10) in the position correction direction. Workpiece processing machine according to claim 25,
characterized,
that the correction wedge (38) is guided on the functional part carrier (10) in such a way (at 40) that it can be displaced in the direction of displacement, but is otherwise operationally secured on the functional part carrier (10). Workpiece processing machine according to one of claims 25 or 26,
characterized,
that the displacement direction is orthogonal to the position correction direction and that the displacement wedge (38) bears against the functional part (22) with a wedge surface (38a) which is inclined in relation to the displacement direction in accordance with its wedge angle. Workpiece processing machine according to one of claims 25-27,
characterized,
that the wedge angle is dimensioned self-locking. Workpiece processing machine according to one of claims 25-28,
characterized,
that the correction wedge acts on the functional part (22) with a first wedge surface (38a) and has an engagement track (38b) for the driver device (42a7) on a back surface inclined against the first wedge surface (38a) at the wedge angle (β). Workpiece processing machine according to one of claims 1-29,
characterized,
that the actuating device (20) is controlled by a correction requirement detection device (48). Workpiece processing machine according to claim 30,
characterized by control means (52, 54, 56, 44) which, when a predetermined sign is detected by the correction need detection device (48), move the driver (42a) from the initial position to the end position, taking the actuator (38) with the driver device (42a7) by one switching step (Δ), this process being repeatable if there is still a need for correction, until no further need for correction can be identified, and if the process is repeated after the driver (42a) enters the end position, the driver device (42a7 ) returns to the uncoupling state, then the driver (42a) returns to the initial position and then the Mit slave device (42a7) passes back into the coupling state. Workpiece processing machine according to one of claims 30 and 31,
characterized,
that the correction requirement detection device (48) for observing an actual product (24 ') generated on the processing machine, for comparing the actual product (24') with a target product (24 _target ), for determining deviation values between actual Product (24 ') and target product (24 _target ) and for converting these deviation values into control signals for the stepper drive (42). Workpiece processing machine according to claim 30 or 31,
characterized,
that the correction requirement detection device (351, 353, 359, 361) is designed to observe the position of at least one measuring point of an already processed product (324 ') relative to a carrier device (370) holding the product of the workpiece processing machine. Workpiece processing machine according to one of claims 30-33,
characterized,
that the correction requirement detection device (351, 353, 359, 361) comprises an optoelectronic observation device. Workpiece processing machine according to claim 34,
characterized,
that the opto-electronic observation device is formed by at least one combination of a light transmitter (353) and a light receiver (361). Workpiece processing machine according to one of claims 1-35,
characterized,
that the workpiece processing machine is designed as a machine tool for processing metallic workpieces. Workpiece processing machine according to claim 36,
characterized,
that the machine tool is designed as a machine which is designed to carry out at least one of the operations bending, punching, welding and assembling. Workpiece processing machine according to one of claims 1-37,
characterized,
that the functional part (22) is formed by a part from a group of parts, which comprises a bending stamp (22), a punch (122) and an embossing stamp. Workpiece processing machine according to one of claims 1-38,
characterized,
that the functional part (80) is formed by a travel limit stop (80) for a periodically moving part (62) of the workpiece processing machine. Workpiece processing machine according to claim 39,
characterized,
that the functional part (80) is formed by a travel limit stop (80) of a workpiece feed device (62). Workpiece processing machine according to claim 40,
characterized,
that the functional part (80) is formed by a travel limit stop (80) of a feed carriage (62) for workpiece raw material (30). Workpiece processing machine according to claim 41,
characterized,
that the feed carriage (62) is designed to feed at least one workpiece raw material (30) from the group of wires and strips.

Images