Transport system for workpieces and method for operating a transport system

Abstract

The invention relates to a transport system (1) for workpieces (2) which are made, preferably at least in part, of wood, wood material, plastics material or the like, the transport system comprising at least one continuous-circulation element (10), which is guided in a circulating direction by a guiding unit (12) and has at least one support surface (14) for supporting a workpiece (2) to be transported, at least one drive (20) for driving the continuous-circulation element (10) at a transporting speed in the circulating direction, a control unit (30) for controlling the at least one drive (20), and at least one sensor (40, 42, 44) for detecting at least one dynamic property of the transport system (1). The control unit (30) is designed to change the transporting speed on the basis of a detection result from the at least one sensor (40, 42, 44) such that at least one dynamic property of the transport system (1) is improved, in particular optimized.

Description

[0001] Transport system for workpieces and method for operating a transport system

[0002] Technical area

[0003] The invention relates to a transport system for workpieces according to the preamble of patent claim 1 and to a method for operating such a transport system.

[0004] State of the art

[0005] A transport system of the type mentioned above is disclosed, for example, in WO 2020 / 229598 A1. Such transport systems are frequently used for conveying and processing panel-shaped workpieces from the furniture and construction element industries.

[0006] When transporting workpieces, ever-increasing demands are placed on both the transport speed and the precision of the transport operation and the resulting workpiece quality. Transport speeds are often 80 m / min and more and can, for example, even reach 300 m / min. It has been shown that such transport systems are subject to high levels of wear, which can impair the precision of the transport operation and thus also the workpiece quality. Furthermore, this results in considerable maintenance and repair costs. Description of the invention

[0007] It is an object of the invention to provide a transport system and a transport method of the type mentioned at the outset which enable precise transport operation, high quality of the transported workpieces and a long service life with low maintenance requirements.

[0008] This object is achieved according to the invention by a transport system according to claim 1 and a method for operating a transport system according to claim 8. Particularly preferred developments of the invention are specified in the dependent claims.

[0009] The invention is based, on the one hand, on the realization that the main cause of excessive wear on a transport system is dynamic stresses resulting from the orbital motion of the endless circulating element, which become increasingly severe with increasing wear on the transport system. On the other hand, the inventors have discovered that even comparatively small changes in the rotational and transport speed of the endless circulating element can contribute to reducing the dynamic stresses that occur and thus significantly increasing the service life of the entire system.

[0010] Against this background, the invention provides that in a generic transport system the control unit is set up to change the transport speed taking into account a detection result of the at least one sensor in such a way that at least one dynamic property of the transport system is improved, in particular optimized. The inventors have found that by specifically adapting the transport speed a drastic improvement in the dynamic behavior and in particular a considerable reduction in vibrations occurring in the transport system can be achieved. This results in significantly reduced wear and tear, but also in significantly more precise transport operation with correspondingly increased workpiece quality. In addition, a long service life and low maintenance costs result.

[0011] Within the scope of the invention, a wide variety of dynamic properties can be detected to achieve the aforementioned objectives. However, it has proven particularly effective if, according to a further development of the invention, the dynamic property is selected from the vibration of the endlessly rotating element, the vibration of the support surface, and the vibration of the guide unit.

[0012] Furthermore, according to a development of the invention, it is provided that the control unit is set up to change the transport speed within a predetermined bandwidth, which is preferably adjustable. In this way, account is taken of the tension in which, on the one hand, the at least one dynamic property should be optimized as far as possible, but on the other hand there is also the desire not to change the transport performance of the transport system too drastically, in particular to impair it. By providing a bandwidth, both requirements can be taken into account, with an adjustable bandwidth helping to take into account the respective requirements, which are made for example by the operator of the transport device, as precisely as possible and to achieve the greatest possible optimization of the at least one dynamic property within this framework.

[0013] It is particularly preferred that the bandwidth is at most 40%, preferably at most 20% of an initial speed before changing the transport speed. These bandwidths have proven advantageous in that they enable very extensive optimization of the at least one dynamic property without excessive changes in the transport speed being necessary. The bandwidth can be both symmetrical and asymmetrical with regard to the initial speed and can, for example, only permit positive values ​​(increases in the transport speed compared to the initial speed). In this way, an improvement in the at least one dynamic property can be combined with an increase in the performance of the transport system.

[0014] Furthermore, according to a development of the invention, the control unit is set up to change the tension of the endless circulating element, taking into account a detection result of the at least one sensor, in such a way that at least one dynamic property of the transport system is improved, in particular optimized. By additionally taking into account or adjusting the tension of the endless circulating element, it is possible to contribute to improving the at least one dynamic property particularly effectively without having to excessively adjust the transport speed. In this way, the advantages according to the invention described above are achieved particularly effectively, while at the same time the overall operation of the transport device only needs to be changed slightly.

[0015] According to a development of the invention, at least one sound sensor is additionally provided, wherein the control unit is set up to change the transport speed and / or tension of the endless circulating element, taking into account a detection result of the at least one sound sensor, in such a way that at least one dynamic property of the transport system and / or the operating noise of the transport system is improved, in particular optimized. By taking into account a sound sensor, an even finer and more complex improvement of the at least one dynamic property can be achieved, since a sound sensor can detect dynamically relevant information which cannot be fully detected, for example, by means of a vibration sensor. In addition, a targeted improvement of the operating noise of the transport system according to the invention can also be brought about.

[0016] A particularly advantageous application of the transport system according to the invention is, according to a further development of the invention, a processing machine according to claim 7. In such a processing machine, the advantages described above have their full effect, since such processing machines often require the transport of the workpiece at very high speeds of, for example, 80 m / min up to 200 m / min and more. Such transport speeds can lead to very high dynamic stresses in the transport system, so that the invention makes a significant contribution to minimizing wear, optimizing the workpiece quality and

[0017] Increase in service life .

[0018] A method for operating a transport system according to the invention is defined in claim 8 and serves to realize the above-mentioned advantages. It is particularly preferred if the control unit changes the transport speed, taking into account the detection result of the at least one sensor, in such a way that at least one dynamic property of the transport system is improved, in particular optimized.

[0019] In addition, a development of the method according to the invention also enables a measuring run (sweep) to be carried out beforehand (i.e. before the actual working operation of the transport system or of a processing machine equipped therewith) or at suitable later times, by operating the at least one endless circulating element at a variable speed over a predetermined speed range and, at a plurality of different speeds, a dynamic property of the transport system is recorded by means of the at least one sensor. This makes it possible to set up a characteristic curve for the at least one dynamic property as a function of the transport speed of the transport system, which characteristic curve can be effectively used in the further operation of the machine when setting, changing and, if necessary, optimising the transport speed.

[0020] According to a further development, it is provided that such a "sweep" can also be performed for different chain tensions in order to enable an even more effective database and, as a result, more precise adjustment of the overall system. For this purpose, according to a further development of the invention, after the "sweep" described above, a tension of the at least one endless circulating element is changed, wherein the at least one circulating element is then operated at a variable speed over a predetermined speed range, and at a plurality of different speeds, a dynamic property of the transport system is detected by means of the at least one sensor.

[0021] The speed range described above can, in principle, extend over the entire operating speed of the transport system or only take into account smaller sub-ranges or bandwidths. With regard to effective adjustment of the transport speed, however, according to a further development of the invention, the speed range extends over at least 20%, preferably at least 40% of the maximum speed range of the transport system. Furthermore, according to a further development of the invention, the values ​​of the at least one dynamic property recorded over the predetermined speed range are stored in a data memory, in particular a database, together with the associated speed values.This allows the control unit to access the acquired data quickly and reliably at any time and thus evaluate an effective adjustment of the transport speed or other parameters.

[0022] Accordingly, according to a further development of the invention, it is provided that the control unit accesses the values ​​of the dynamic property and the associated speed stored in the data memory and, on this basis, adjusts the transport speed of the endless circulating element.

[0023] Furthermore, according to a further development of the invention, the rigidity and / or the weight of the guide unit are adjusted, in particular increased, on the basis of the values ​​of the dynamic property and the associated speed stored in the data memory in such a way that at least one dynamic property is improved at a desired transport speed. This makes a further contribution to achieving an improvement in at least one dynamic property with minimal or, if appropriate, no adjustment of the transport speed, so that the above-mentioned advantages can be combined with a minimal change in the performance of the transport system. Brief description of the drawings

[0024] Fig. 1 shows schematically a side view of a processing device with a transport system according to an embodiment of the invention;

[0025] Fig. 2 shows a schematic diagram with an oscillation amplitude as a function of a transport speed.

[0026] Detailed description of preferred embodiments

[0027] Preferred embodiments of the invention are described in detail below with reference to the accompanying drawings.

[0028] A processing machine 100 for processing a workpiece 2 is shown schematically in a side view in Fig. 1. The processing machine 100 is used to process workpieces 2 which, for example, consist entirely or partially of wood, wood-based materials, plastic or similar materials and material combinations. Suitable materials here include gypsum, plasterboard, WPG, SPG and other materials. Such workpieces are widely used in the furniture and building element industry, for example as carcass parts, fronts, doors, etc., but also in the area of ​​interior fittings, for example as wall or floor panels.

[0029] The processing machine 100 comprises a processing unit 101 for carrying out the actual workpiece processing. For this purpose, the processing unit 101 can, for example, have a processing tool 102 which can, for example, carry out a cutting or other shaping process. Alternatively or additionally, the processing unit 101 can also be designed for other processing operations, such as coating (e.g., applying a coating material, such as an edge), patterning (e.g., printing), or a variety of other operations which change the shape or appearance of the workpiece 2.

[0030] In addition, the processing machine 100 comprises a transport system 1 which serves to move the workpieces 2 to be processed with respect to the processing unit 101 or generally to bring about a relative movement.

[0031] In the present embodiment, the transport system 1 of the processing machine 100 is designed as a continuous transport system and comprises one or more (optionally parallel) endless circulating elements 10, for example in the form of a chain, a belt, or the like. The endless circulating element has a support surface 14 on its outer circumference for supporting the workpiece 2 to be transported. The support surface 14 can be formed, for example, by suitable plates.

[0032] The endless circulating element 10 is guided by a guide unit 12, which may, for example, comprise a beam carrier and other suitable components. Thus, the endless circulating element can move in a guided manner around the guide unit 12 in a direction of rotation at a transport speed and, for this purpose, can be driven by a drive 20. The drive 20 is connected to a control unit 30, which controls the drive 20 and, in particular, can set different transport speeds.

[0033] Furthermore, the transport system 1 in the present embodiment comprises a plurality of sensors 40, 42 and 44 for detecting one or more dynamic properties of the transport system. A vibration sensor 40 is attached to the guide unit 12, a further vibration sensor 42 is attached to the endless circulating element 10 and a sound sensor 44 is provided at a suitable location in the region of the transport system. The sensors are thus capable of detecting vibration of the endless circulating element 10, the support surface 14 and the guide unit 12, wherein the sound sensor 44 can at least indirectly detect corresponding information as well as generally also the operating noise.

[0034] Although not shown in Fig. 1, the sensors 40, 42, 44 are connected to the control unit 30 so that the detection results of the respective sensors can be transferred to the control unit 30. On this basis, the control unit 30 is configured to change the transport speed of the transport system 1 such that at least one dynamic property of the transport system is improved.

[0035] The improvement of the at least one dynamic property can in principle be an optimization over the entire speed range. Furthermore, it is also advantageously possible for the control unit 30 to change the transport speed within a predetermined bandwidth B, B', which is illustrated in Fig. 2. Fig. 2 shows purely schematically a possible profile of an oscillation amplitude a as a function of the transport speed v. The oscillation amplitude can be, for example, the amplitude of the endless circulating element 10 or the guide unit 12, as detected, for example, by at least one of the sensors.

[0036] It can be seen that the amplitude a is subject to strong fluctuations with increasing transport speed v and has a relatively large value, for example, at an initial speed A, which may be provided or desired by an operator of the machine. The invention now provides for changing the transport speed in such a way that the amplitude a (or another relevant dynamic

[0037] property ) is improved .

[0038] As mentioned above, the control unit 30 can be configured to vary the transport speed within a predetermined range compared to the initial speed A. The bandwidth can be adjustable, for example to a relatively large bandwidth B (e.g., a maximum of 40% of the initial speed) or to a somewhat smaller bandwidth B' (e.g., a maximum of 20% of the initial speed).

[0039] If a corresponding bandwidth has been defined, the control unit is set up to set a transport speed v within the bandwidth at which the dynamic property is as favorable as possible, i.e. in this case the amplitude a is as small as possible. The user or operator of the transport system 1 can, for example, also specify that only increases in speed are to be permitted within the bandwidth, or that reductions in speed are to be permitted according to certain criteria, for example if the improvement in the dynamic property can be improved considerably more with a (possibly slight) reduction in the transport speed than with an increase in the transport speed v.

[0040] Another parameter in Fig. 2 is the tension of the endless circulating element, wherein Fig. 2 shows schematic curves for two different tensions S and S '. The curves show that the amplitude curve for the two voltages S and S ' is basically similar, but within, for example, the smaller bandwidth B ', a significantly greater reduction in the amplitude a can be achieved for the chain tension S ' than for the tension S . In addition, the amplitude a is generally lower for the chain tension S ' than for the chain tension S . The control unit can take this into account by adjusting the tension of the endless circulating element 10, taking into account a detection result from one or more of the sensors 40, 42 and 44, in such a way that the amplitude a is reduced or another dynamic property is improved.To adjust the chain tension, the transport system 1 can have a suitable chain tensioner 16, which is shown schematically in Fig. 1.

[0041] The adjustment of the transport speed described above can in principle be carried out at any time during use of the transport system and, if necessary, also repeatedly, for example if the operating parameters of the transport system have changed (e.g. mass of the workpieces, ambient temperature, wear, etc.). In addition, it is also possible to carry out a systematic "sweep" of the transport speed when commissioning the transport system 1 or also at later times, in which the at least one endless circulating element 10 is operated at a variable speed over a predetermined speed range C (cf. Fig. 2) and a dynamic property of the transport system 1, such as the amplitude a, is detected at a plurality of different speeds by means of one or more of the sensors 40, 42, 44.For example, at least ten, preferably at least 100 or even significantly more measuring points can be recorded (i.e. measured at a corresponding number of different speeds). The speed range C can extend over the entire speed range of the transport system 1 or only over a partial range, which should, however, comprise at least 20%, preferably at least 40% of the maximum speed range in order to obtain meaningful results. In addition, the sweep can also be carried out at several different voltages S and S ' of the endless circulating element 10 in order to create a corresponding database here too.

[0042] The values ​​of the at least one dynamic property and the associated speeds recorded in this way are then stored in the data storage 32 shown in Fig. 1 and are thus available to the control unit 30 at any time. In principle, the data storage can be located anywhere, such as in the cloud. Furthermore, data from different machines can be combined and jointly evaluated in the data storage 32 or a database stored therein in order to provide corresponding data for the control unit 30.

[0043] A further possibility for improving the dynamic properties of the transport system 1 is to change the rigidity and / or the weight of the guide unit 12. The data acquired above by means of the sensors 40, 42 and / or 44 can also form a very good basis for such an optimization. For example, this data can be incorporated into numerical simulations, on the basis of which it can be determined whether and, if so, which areas of the guide unit can be provided with stiffeners or their mass can be adjusted in order to improve the dynamic properties of the transport system.

Claims

CLAIMS 1. Transport system (1) for workpieces (2), which preferably consist at least partially of wood, wood material, plastic or the like, comprising: at least one endless circulating element (10) which is guided by a guide unit (12) in a direction of rotation and has at least one support surface (14) for supporting a workpiece (2) to be transported, at least one drive (20) for driving the Endless circulating element (10) with a Transport speed in the direction of rotation, a control unit (30) for controlling the at least one drive (20), and at least one sensor (40, 42, 44) for detecting at least one dynamic property of the transport system (1), characterized in that the control unit (30) is set up to change the transport speed taking into account a detection result of the at least one sensor (40, 42, 44) in such a way that at least one dynamic property of the transport system (1) is improved, in particular optimized.

2. Transport system according to claim 1, wherein the dynamic property is selected from vibration of the endless circulating element (10), vibration of the support surface (14) and vibration of the guide unit (12).

3. Transport system according to claim 1 or 2, wherein the control unit (30) is arranged to change the transport speed within a predetermined bandwidth (B, B'), which is preferably adjustable.

4. Transport system according to claim 3, wherein the belt width (B, B') is at most 40%, preferably at most 20% of an initial speed (A) before changing the transport speed.

5. Transport system according to one of the preceding claims, in which the control unit (30) is set up to change the voltage (S1, S2) of the endless circulating element (10) taking into account a detection result of the at least one sensor (40, 42, 44) in such a way that at least one dynamic property of the transport system (1) is improved, in particular optimized.

6. Transport system according to one of the preceding claims, in which at least one sound sensor (44) is provided, wherein the control unit (30) is set up to change the transport speed and / or tension of the endless circulating element (10) taking into account a detection result of the at least one sound sensor (44) in such a way that at least one dynamic property of the transport system (1) and / or the operating noise of the transport system (1) is improved, in particular optimized.

7. A processing machine (100) for processing a workpiece (2), which preferably consists at least in sections of wood, wood-based material, plastic or the like, comprising: a processing unit (101) for processing the Workpiece (2), and a transport system (1) according to one of the preceding claims for bringing about a relative movement between the processing unit (101) and the workpiece (2) and for supporting the workpiece (2) during processing.

8. Method for operating a transport system (1) according to one of claims 1 to 6, in which the at least one endless circulating element (10) is operated at a predetermined speed, by means of the at least one sensor (40, 42, 44) at least one dynamic property of the transport system (1) is detected, and the detection result of the at least one sensor (40, 42, 44) of the control unit (30) and / or a data memory (32).

9. The method according to claim 8, wherein the control unit (30) changes the transport speed taking into account the detection result of the at least one sensor (40, 42, 44) such that at least one dynamic property of the transport system (1) is improved, in particular optimized.

10. Method according to claim 8 or 9, wherein the at least one endless circulating element (10) is operated at a variable speed over a predetermined speed range (C) and at a plurality of different speeds a dynamic property of the transport system (1) is detected by means of the at least one sensor (40, 42, 44).

11. Method according to claim 10, wherein a tension of the at least one endless circulating element (10) is changed, wherein subsequently the at least one endless circulating element (10) with variable Speed ​​over a predetermined speed range (C) and at a plurality of different speeds a dynamic property of the transport system (1) is detected by means of the at least one sensor (40, 42, 44).

12. The method according to claim 10 or 11, wherein the Speed ​​range (C) is at least 20%, preferably at least 40% of the maximum speed range of the transport system (1).

13. Method according to one of claims 10-12, wherein the values ​​of the at least one dynamic property recorded over the predetermined speed range (C) are stored in a data memory (32), in particular a database, together with the associated speed values.

14. The method according to claim 13, wherein the control unit (30) accesses the values ​​of the dynamic property and the associated speed stored in the data memory (32) and sets the transport speed of the endless circulating element (10) on this basis.

15. Method according to one of claims 10-14, wherein the stiffness and / or the weight of the guide unit (12) is adjusted on the basis of the values ​​of the dynamic property and the associated speed stored in the data memory (32) in such a way that in particular, increased so that at least one dynamic property is improved at a desired transport speed.

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