WO2023083450A1

WO2023083450A1 - Method and device for intermittently supplying a strip- or wire-form semifinished material to a press

Info

Publication number: WO2023083450A1
Application number: PCT/EP2021/081370
Authority: WO
Inventors: Josef Thomas Hafner; Daniel Straub
Original assignee: Bruderer Ag
Priority date: 2021-11-11
Filing date: 2021-11-11
Publication date: 2023-05-19

Abstract

The invention relates to a method for intermittently supplying a strip- or wire-form semifinished material to a press, preferably to a punch press. In the process, the semifinished material to be supplied is fed in a feeding phase by means of a sliding gripper (14) which is driven by a first drive (1) during feeding. In a non-feeding phase, the semifinished material to be supplied is held fast by means of a stationary clamping gripper (18) and the sliding gripper (14) is retracted by a second drive (6) which is formed separately from the first drive (1). The method according to the invention makes it possible to optimize the drive in servo-gripper feeds. The use according to the invention of separate drives (1, 6) for the feeding movement and the retracting movement of the sliding gripper (14) makes a distinct downtime available for each of the drives (1, 6), with the result that, compared with the currently known solutions, with the same feed performance, a clear reduction in thermal load becomes possible or, with the same thermal load, a clear increase in the drive performance becomes possible.

Description

Method and device for intermittently feeding a strip or wire-shaped semi-finished material to a press

TECHNICAL AREA

The present invention relates to a method and a device for the intermittent feeding of a strip or wire-shaped semi-finished material to a press and a use of the device according to the preambles of the independent patent claims.

STATE OF THE ART

In the industrial production of small pressed and stamped parts, high-speed presses are used today, to which a strip or wire-shaped semi-finished material is intermittently fed by means of a synchronized feed device. For feeding, the semi-finished material is clamped in the feeding device between two rollers or in sliding tongs and is fed through a counter-rotating movement of the rollers by a certain angle of rotation or a linear movement of the sliding tongs. After each advance, the clamping of the semi-finished material between the rollers or in the sliding tongs is released and the semi-finished material is fixed by means of a clamping ruler or clamping tongs. Then follows, if necessary after an additional intermediate lifting step in which the semi-finished material in the feed device is briefly released in order to enable exact positioning of the same by means of a positioning element in the press, the processing of the semi-finished material in the press, which is followed by the next feed process. While in the case of roller feeds the rollers stand still in the non-feeding phase, in the case of tong feeds the sliding tongs are pulled back into the starting position in the non-feeding phase. It follows accordingly With roller feeds, the system-related advantage is that their drives do not have to deliver any power in the non-feeding phase and are accordingly significantly less thermally stressed than the drives in the gripper feeds known today. The roller feed devices also have the advantage that they are relatively compact, inexpensive and robust and are also suitable for relatively high feed frequencies. However, they have the serious disadvantage that they are unsuitable for sensitive semi-finished materials, as these are exposed to enormous surface pressure as a result of the linear contact surface when they are advanced with the rollers, which almost inevitably leads to marks and scratches.

The gripper feed devices known today, on the other hand, are ideally suited for the processing of very sensitive semi-finished materials, since these are not rolled over when they are fed, but are only clamped in the grippers over a relatively large area at individual points, so that there is only local contact between the feed element and the semi-finished product, and also much less contact surface pressures are present. However, the decisive disadvantage of the gripper feed devices known today is that they only allow relatively low feed frequencies because relatively large masses have to be moved due to the sliding gripper. This applies in particular to gripper feeds which are driven by their own motors, in particular servo gripper feeds. While the so-called mechanical feeds can draw practically unlimited drive energy from the flywheel of the press, in the case of feeds equipped with their own drive motors, the entire drive energy must be provided by the drive motor. At the same time, however, the rotational mass inertia of the drive motors also increases with increasing drive power, so that the motors perform poorly have to be designed rather tightly and are therefore subject to a correspondingly high thermal load.

PRESENTATION OF THE INVENTION

The task therefore arises of providing technical solutions which do not have the aforementioned disadvantages of the prior art or at least partially avoid them.

This object is achieved by the subject matter of the independent patent claims.

According to this, a first aspect of the invention relates to a method for the intermittent feeding of a strip or wire-shaped semi-finished material to a press, preferably to a stamping press. In this case, the semi-finished material to be supplied is advanced in an advance phase by means of a sliding tongs, which is driven by an advance drive (first drive according to the claim) during advance. In a non-advance phase, the semi-finished material to be supplied is held in place by means of stationary clamping tongs and the sliding tongs are pulled back with a retraction drive (second drive as claimed). Feed drive and retraction drive are designed separately from each other.

The method according to the invention makes it possible to optimize the drive in the case of servo gripper feeds. The use according to the invention of separate drives for the advance movement and the retraction movement of the sliding tongs means that a pronounced downtime is available for each of the drives, as a result of which a clear reduction in the thermal stress is possible or can be avoided compared to the solutions known today with the same advance performance. a significant increase in drive power with the same thermal stress. In addition, the drive for retracting the sliding tongs can be designed to be smaller than the feed drive because it does not have to perform any feed work. When the sliding tongs are advanced, the retraction drive is preferably decoupled with the feed drive from the sliding tongs, and the feed drive is preferably decoupled from the sliding tongs with the retraction drive when the sliding tongs are retracted. The drives are thus decoupled from one another when carrying out their respective work (advance or retraction of the sliding tongs), which is preferably effected by control-related and/or mechanical decoupling. This allows the drives to be further optimized to the effect that none of the drives has to overcome the inertia of the other drive and the drive for retracting the sliding tongs can be designed to be significantly smaller than the feed drive because it only overcomes its own inertia and that of the feed tongs must .

Advantageously, servomotors are used for the feed drive and for the retraction drive, specifically preferably a servomotor with a greater maximum drive power for the feed drive than for the retraction motor. Such drives can be precisely controlled and are commercially available in various sizes and designs.

In a first variant, it is preferred that the drive-related decoupling takes place in terms of control technology by torque release of the respective servomotor that is not currently performing its intended work. This variant requires a minimum of mechanical devices to implement the decoupling.

In a second preferred variant, the decoupling of the drive takes place by mechanically decoupling the respective servo motor from the sliding tongs during its break in work or for the working direction of the other servo motor, e.g. B. via a clutch or overrunning clutch. In particular, the latter variant with overrunning clutches has the advantage that a reliable mechanical forced decoupling of the drives with regard to their respective working directions.

If rotary drives are used for the advance drive and the retraction drive, which is preferred, it is advantageous to use these for advancing or retracting. retraction of the sliding tongs in each case via a drive pinion and a toothed rack with the sliding tongs. In this way, the rotational movement of the drives can be converted relatively easily into the translational movement of the sliding tongs, and the displacement path can be easily adjusted via the angle of rotation of the drives.

It is further preferred that a freewheel clutch is arranged between the respective drive and the respective drive pinion in order to mechanically decouple the respective drive from the drive movement of the other drive.

Furthermore, it is preferred that the sliding tongs are opened and closed by means of a third drive according to the claims and the clamping tongs are opened and closed by means of a fourth drive according to the claims. In this case, these drives are designed separately from one another and separately from the advance drive and the retraction drive. In this way, maximum flexibility with regard to the opening and closing times and forces is achieved and the feed drive and retraction drive can be further optimized because they do not have to contribute to the opening and closing work and also do not have to overcome any additional inertia in this regard.

Servomotors are preferably used for the third drive according to the claims and the fourth drive according to the claims , it being further preferred that these are each connected to the sliding tongs or tongs via spindles and spindle nuts . of the clamping tongs to effect opening and closing of the tongs. A second aspect of the invention relates to a device for the intermittent feeding of a strip or wire-shaped semi-finished material to a press, preferably according to the method according to the first aspect of the invention.

The device comprises a sliding tongs 14, which reciprocate during operation, for advancing the stock material in an advancing phase, and a fixed clamping tongs, for holding the stock material in a non-advancing phase. The device has a feed drive (first drive as claimed) for advancing the sliding tongs and a retraction drive (second drive as claimed) for retracting the sliding tongs, which retraction drive is separate from the feed drive.

The invention makes it possible to further optimize the drive for servo gripper feeds. The use according to the invention of separate drives for the advance movement and the retraction movement of the sliding tongs means that a pronounced downtime is available for each of the drives, as a result of which a clear reduction in the thermal stress is possible or can be avoided compared to the solutions known today with the same advance performance. a significant increase in drive power with the same thermal stress. In addition, the drive for retracting the sliding tongs can be designed to be smaller than the feed drive because it does not have to perform any feed work.

The device is preferably designed in such a way that the retraction drive is or can be decoupled from the sliding tongs in terms of drive when the sliding tongs are advanced with the feed drive, and that the feed drive is or can be decoupled from the sliding tongs in terms of drive when the sliding tongs are retracted with the retraction drive. The device is therefore designed in such a way that the drives are decoupled or can be decoupled from each other when performing their respective work (advance or retraction of the sliding tongs), which is preferably done by control technology and/or mechanical decoupling or. can be done. This makes it possible to further optimize the drives because none of the drives has to overcome the inertia of the other drive and the drive for retracting the sliding tongs can be designed significantly smaller than the feed drive because it only overcomes its own inertia and that of the feed tongs must .

Advantageously, the advance drive and the retraction drive are designed as servomotors, it being further preferred that the servomotor for the advance has a greater maximum drive power than the servomotor for the retraction. Such drives can be precisely controlled and are commercially available in various sizes and designs.

In a first variant, it is preferred that the device is designed in such a way that the drive-related decoupling takes place in terms of control technology by torque release of the respective servomotor that is not currently performing its intended work or. can be done. This variant requires a minimum of mechanical devices to implement the decoupling.

In a second preferred variant, the device is designed in such a way that the decoupling of the drive is achieved by mechanically decoupling the respective servo motor from the sliding tongs during its break in work or when it is not working. takes place or can take place for the working direction of the other servo motor, e.g. B. via a clutch or overrunning clutch. In particular, the last-mentioned variant with overrunning clutches has the advantage that there is a reliable mechanical forced decoupling of the drives with regard to their respective working directions. If rotary drives are used for the advance drive and the retraction drive, which is preferred, then it is advantageous that they can be used for advancing or retracting. Retraction of the sliding tongs are each coupled via a drive pinion and a rack to the sliding tongs. In this way, the rotational movement of the drives can be converted relatively easily into the translational movement of the sliding tongs, and the displacement path can be easily adjusted via the angle of rotation of the drives.

In a further preferred embodiment, the device comprises a third drive according to the claims for opening and closing the sliding tongs and a fourth drive according to the claims for opening and closing the clamping tongs, which drives are designed separately from one another and separately from the advance drive and the retraction drive. In this way, maximum flexibility with regard to the opening and closing times and forces is achieved and the feed drive and retraction drive can be further optimized because they do not have to contribute to the opening and closing work and also do not have to overcome any additional inertia in this regard.

The third drive according to the claims and the fourth drive according to the claims are preferably designed as servomotors, it being further preferred that these are each connected to the sliding tongs or of the clamping tongs are coupled to effect opening and closing of the tongs.

A third aspect of the invention relates to the use of the device according to the second aspect of the invention for feeding a strip or wire Semi-finished material to a stamping press. With such a use, the advantages of the invention come into play particularly clearly.

Brief description of the drawings

Further preferred embodiments of the invention result from the dependent claims and from the following description with reference to the figures. Show :

Fig. 1 shows a perspective front view of a feed device according to the invention;

Fig. 2 is a rear perspective view of the feed device of FIG. 1 ;

Fig. 3 shows a perspective cross-section through the feed device from FIGS. 1 and 2 along the line A-A in FIG. 1 .

Fig. 4 shows a perspective longitudinal section through the feed device from FIGS. 1 and 2 along the line B-B in FIG. 2 .

Fig. 5 shows a perspective longitudinal section through the feed device from FIGS. 1 and 2 in the area of the drive pinion of the pull-back motor.

way of carrying out the invention

FIGS. 1 and 2 show perspective views obliquely from above of the front (FIG. 1) and the rear (FIG. 2) of a device according to the invention for the intermittent feeding of a strip-shaped semi-finished material to a stamping press.

As can be seen, the feed device has sliding tongs 14, which run back and forth during operation, for advancing the semi-finished material (not shown) in the advancing phase, and fixed clamping tongs 18, for holding the semi-finished material in place in the non-advancing phase. The device also has a first servomotor 1 for advancing the sliding tongs 14 and a second servomotor 6 for the retraction of the sliding tongs 14, which occurs in the non-advancing phase. The first servomotor 1 for the advance movement of the sliding tongs 14 is significantly larger or more powerful than the second servomotor 6 for its retraction movement.

As can be seen in combination with FIGS. 3 and 4, which show perspective sectional views through the feed device according to the invention, namely a cross section along line A-A in FIG. 1 (FIG. 3) and a longitudinal section along line B-B in FIG. 2 ( 4), the servomotors 1, 6 are each coupled to the sliding tongs 14 via a drive pinion 4, 9 and a toothed rack 5, 10.

As can also be seen in combination with Fig. 5, which shows a perspective longitudinal section through the feed device in the area of the drive pinion 9 of the retraction motor 6, freewheel clutches 3, 8 with opposite freewheeling directions are arranged between the servomotors 1, 6 and the associated drive pinions 4, 9 , for the respective mechanical drive-related decoupling of the servomotor 1, 6 from the sliding tongs 14 with regard to the drive direction of the other servomotor 6, 1. The two overrunning clutches 3, 8 therefore result in a forced mechanical decoupling of the servomotors 1, 6 with regard to their respective working directions, so that the second servomotor 6 is decoupled in terms of drive from the sliding tongs 14 with the first servomotor 1 when the sliding tongs 14 are advanced, and the first servomotor 1 is decoupled in terms of drive from the sliding tongs 14 with the second servomotor 6 when the sliding tongs 14 are retracted. The drive pinions 4, 9 with the overrunning clutches 3, 8 have their own bearings 2, 7 to relieve the engine bearings.

As can also be seen in particular from FIGS. 3 and 4, the feed device according to the invention comprises a third servomotor 11 for opening and closing the sliding tongs 14 and a fourth Servomotor 15 for opening and closing the clamp 18 . These servomotors 11, 15 are each connected via spindles 12, 16 and spindle nuts 13, 17 to the sliding tongs 14 or the clamp pliers 18 coupled to effect the opening and closing movement. While preferred embodiments of the invention are described in the present application, it should be clearly pointed out that the invention is not limited to these and can also be implemented in other ways within the scope of the following claims.

Claims

PATENT CLAIMS

1. Method for the intermittent feeding of a strip or wire-shaped semi-finished material to a press, wherein the semi-finished material to be fed is driven by a first drive (1) in a feed phase by means of sliding tongs (14) and in a non-feeding phase by means of fixed clamping tongs (18) is held, and wherein the sliding tongs (14) in the non-advance phase driven by a second drive (6), which is formed separately from the first drive (1), is retracted.

2. The method according to claim 1, wherein the second drive (6) is decoupled from the sliding tongs (14) in terms of drive when the sliding tongs (14) are advanced with the first drive (1) and the first drive (1) when the sliding tongs (14) are retracted ( 14) with the second drive (6) is decoupled in terms of drive from the sliding tongs (14).

3. The method according to claim 2, wherein the respective drive-related decoupling takes place in terms of control technology and/or mechanically.

4. The method according to any one of the preceding claims, wherein servomotors are used for the first drive (1) and the second drive (6), and in particular wherein a servomotor with a greater maximum drive power is used for the first drive (1) than for the second drive (6).

5. The method according to claim 3 and according to claim 4, wherein the respective drive-related decoupling takes place in terms of control technology by torque release of the respective servomotor (1, 6). 6. The method according to claim 3 and according to claim 4, wherein the respective drive-related decoupling by mechanical decoupling of the respective drive (1,

6) takes place, in particular via a clutch or overrunning clutch (3, 8).

7. The method according to any one of the preceding claims, wherein for the first and the second drive (1, 6) rotary drives are used, which each have a drive pinion (4, 9) and a rack for advancing or retracting the sliding tongs (14). (5, 10) are coupled with the sliding tongs (14).

8. The method according to claim 6 and according to claim 7, wherein a freewheel clutch (3, 8) is arranged between the respective drive (1, 6) and the respective drive pinion (4, 9), for the respective drive-related decoupling by mechanical decoupling

9. The method according to any one of the preceding claims, wherein the sliding tongs (14) are opened and closed by means of a third drive (11) and the clamping tongs (18) are opened and closed by means of a fourth drive (15), and wherein these drives (11 , 15) are formed separately from one another and separately from the first drive (1) and the second drive (6).

10. The method according to claim 9, wherein servomotors are used for the third drive (11) and the fourth drive (15), and in particular, wherein these are each connected via spindles (12, 16) and spindle nuts (13, 17) to the sliding tongs ( 14) or the clamping tongs (18). 14

11. Device for the intermittent feeding of a strip or wire-shaped semi-finished material to a press, in particular according to the method according to one of the preceding claims, with a sliding tongs (14) running back and forth during operation, for advancing the semi-finished material in an advancing phase, and a stationary clamping tongs (18) for holding the semi-finished material in a non-advancing phase, the device for advancing the sliding tongs (14) having a first drive (1) and for retracting the sliding tongs (14) having a second drive (6). , which is formed separately from the first drive (1).

12. Device according to claim 11, wherein the device is designed in such a way that the second drive (6) is or can be decoupled in terms of drive from the sliding tongs (14) when the sliding tongs (14) are advanced with the first drive (1) and the first drive (1) when the sliding tongs (14) are pulled back with the second drive (6), the drive is uncoupled or can be uncoupled from the sliding tongs (14).

13. The device according to claim 12, wherein the device is designed in such a way that the respective drive-related decoupling takes place or can take place in terms of control technology and/or mechanically.

14. Device according to one of claims 11 to 13, wherein the first drive (1) and the second drive (6) are designed as servomotors, and in particular wherein the first drive (1) has a greater maximum drive power than the second drive ( 6) •

15. The device according to claim 13 and according to claim 14, wherein the device is designed in such a way 15 is that the respective drive-related decoupling takes place or can take place in terms of control technology by torque release of the respective servomotor (1, 6).

16. Device according to claim 13 and according to claim 14, wherein the device is designed such that the respective drive-related decoupling takes place or can take place by mechanically decoupling the respective drive (1, 6), in particular by means of a clutch or overrunning clutch.

17. Device according to one of claims 11 to 16, wherein the first and the second drive (1, 6) are rotary drives, which each have a drive pinion (4, 9) and a rack for advancing or retracting the sliding tongs (14). (5, 10) are coupled to the sliding tongs (14).

18. Device according to claim 16 and according to claim 17, wherein a freewheel clutch (3, 8) is arranged between the respective drive (1, 6) and the respective drive pinion (4, 9), for the respective drive-related decoupling by mechanical decoupling

19. Device according to one of claims 11 to 18, further comprising a third drive (11) for opening and closing the sliding tongs (14) and a fourth drive (15) for opening and closing the clamping tongs (18), which drives (11, 15) are formed separately from each other and separately from the first drive (1) and the second drive (6).

20. Device according to claim 19, wherein the third drive (11) and the fourth drive (15) are designed as servomotors, and in particular, wherein these each have spindles (12, 16) and spindle nuts 16 (13, 17) with the sliding pliers (14) or the clamping pliers

(18) are coupled.

21. Use of the device according to one of claims 11 to 20 for feeding a strip or wire-shaped semi-finished material to a stamping press.