JP7538356B2 - How to operate a production line for processing metal plate sheets - Google Patents

Description

The present invention relates to a method for operating a production line for processing metal sheets, as described in the generic part of claim 1.

From DE 102019118647, a production line for processing sheet metal sheets is known, which has several different machine units, the transport path of the sheet metal sheets through which is, for example, linear, and which are provided as machine units successively in the transport direction of the sheet metal sheets to be processed with sheet metal printing machines and/or painting machines and/or loading stations and/or dryers and/or unloading stations, at least two machine units each having at least one transport device for transporting at least one sheet metal sheet, which is placed individually on a transport plane, the transport device of the loading station having a wire frame for lifting the sheet metal sheet, which is formed so as to pass from bottom to top through the transport plane of the sheet metal sheets, in the area where the sheet metal sheets are fed to the loading station, around a rotation axis extending transversely to the transport direction of the sheet metal sheets to be transported in a circular manner.

The problem underlying the present invention is to provide a method for operating a production line for processing metal sheet, in which an unobstructed and individual transport of the metal sheet through the production line is guaranteed during mass production of the metal sheet at a production rate of several thousand metal sheet per hour.

The above problem is solved in the present invention by the features of claim 1. The dependent claims relate to advantageous configurations and/or developments of the solution found.

The advantages achievable by the invention are, in particular, that during mass production of metal sheet sheets at production speeds of several thousand metal sheet sheets per hour, a disturbance-free, individual transport of the metal sheet sheets through the production line is ensured, for example with monitoring of synchronization points and/or without unintentional running-up and/or tilting or jamming of the continuously transported metal sheet sheets.

An embodiment of the invention is shown in the drawings and explained in detail below, which shows further advantages of the solution found.

FIG. 1 shows a production line for processing plate metal sheets, with multiple machine units. FIG. FIG. FIG. FIG. FIG. 2 is a perspective view of a load station having a transport module disposed in front of it; FIG. 7 is a plan view of the load station of FIG. 6. FIG. 1 is a sketch of an arrangement of clocked nozzles formed within a load station; 13 is a sketch of a control for monitoring and/or setting a synchronization point in a load station. FIG. 13 shows a lifting device that uses compressed air nozzles and/or electromagnets to assist in lifting the wire frame. FIG. 13 shows a lifting device that uses a cam to assist in lifting the wire frame. FIG. 13 shows a lifting device that uses a lever to assist in lifting the wire frame. FIG. 13 shows a lifting device that uses a lever to assist in lifting the wire frame. FIG. 13 shows a lifting device that uses tappets to assist in lifting the wire frame. FIG. 13 shows a lifting device that uses tappets to assist in lifting the wire frame. FIG. 1 shows a production line having a wire frame suspended and connected to the lower span of a tensioning means. FIG. 1 shows a continuous dryer having tensioning means in multiple horizontal planes arranged vertically one above the other.

In industrial sheet metal printing, sheet metal sheets 08 (FIG. 2) are usually printed with at least one printing image in a production line 01 by application of at least one printing fluid using a sheet metal printing machine 03 and/or painted in a sheet metal painting machine 06, respectively, fully or partially, for example to protect the surface of the sheet metal sheets 08 or at least the printing image and/or to generate, for example, a gloss effect. The sheet metal sheets 08 to be processed in this way have a format of, for example, 500 mm×650 mm to 950 mm×1,900 mm, respectively, with a sheet metal thickness of, for example, 0.1 mm to 1.0 mm, preferably 0.14 mm to 0.5 mm. Each of these sheet metal sheets 08 may have a mass of, for example, several hundred grams to several kilograms, for example at least 300 grams to 5 kilograms or more, depending on the format and material of the sheet metal sheets 08 (whether made of tin-plated or tin-free steel or made of aluminum). In particular, during the production of metal sheet packaging, i.e. during metal sheet packaging printing, such metal sheet sheets 08 are printed and/or painted industrially in mass production at production rates of several thousand metal sheet sheets 08 per hour, for example at least 6,000 metal sheet sheets 08 per hour.

Figure 1 shows, in a highly simplified schematic diagram, an example of a production line 01 for processing sheet metal sheets 08 with a number of such machine units, which are respectively arranged in a row in succession and which cooperate together to carry out the production of processing sheet metal sheets 08. In this production line 01, in the conveying direction T of the sheet metal sheets 08 to be processed (Figure 2), for example a sheet metal printing machine 03 and/or a sheet metal painting machine 06 are provided, followed by a loading station 02, a continuous dryer 17 and an unloading station 07, in particular the loading station 02 and/or the unloading station 07, which can each cooperate with a conveying module 04, which can be formed, for example, as an independent machine unit. The sheet metal printing machine 03 and the sheet metal painting machine 06 can also be formed together in a single machine unit. The machine unit formed as a continuous dryer 17 is formed, for example, as a hot air dryer.

In practical use, it has been found that metal sheet sheets 08 conveyed through the production line 01 at high speeds tend to become jammed during the conveying of the metal sheet sheets 08, in particular due to friction effects in the respective conveying planes of the metal sheet sheets 08 and/or as a result of dirt on the respective conveying paths of the metal sheet sheets 08. Jamming friction effects also occur, for example, during excessive wear or during deterioration of the belt conveying system used for conveying the metal sheet sheets 08. Each of these undesirable effects can cause, for example, that multiple metal sheet sheets 08 conveyed one after the other through the production line 01 unintentionally ride up and/or tilt or get stuck on each other. The metal sheet sheets 08 can also be rotated in their respective conveying planes and deviate from the linear conveying path of the metal sheet sheets 08, which can result in collisions, for example, with other metal sheet sheets 08 and/or with components of one of the multiple machine units of this production line 01. And even if no collisions occur, at least one free interval between successively conveyed sheet metal sheets 08 in the production line 01, i.e. the interval between the rear edge of a first sheet metal sheet 08 and the front edge of the next following sheet metal sheet 08, may change, resulting in a shift of the so-called synchronization point. This means, in particular, that the position of the front edge of one sheet metal sheet 08 shifts relative to the devices arranged in the different machine units of the production line 01. Due to such a shift of the synchronization point, the acceleration and/or deceleration steps which are planned during the conveyance of said sheet metal sheets 08 through the production line 01, for example in connection with the sheet metal printing machine 03 and/or the sheet metal painting machine 06, may become out of step, so that in particular the cooperation of the machine units which are chained together during the production process, for example the sheet metal printing machine 03 or the sheet metal painting machine 06, the at least one conveying module 04, the loading station 02, the continuous dryer 17 and the unloading station 07, is disturbed. Such events can lead to undesirable adverse effects and/or damage to production, even resulting in lost production due to machine shutdowns caused by failures.

At least each transport module 04 and/or loading station 02 and/or unloading station 07 has, as one of its structural units, at least one specific transport device 09 (FIG. 3) for transporting the sheet metal sheets 08. The transport path through the production line 01 is, for example, linear. At least the machine units configured as loading stations 02 or as continuous dryers 17 or as unloading stations 07 and arranged successively in the transport direction T of the sheet metal sheets 08 are each provided for transporting the sheet metal sheets 08 and are linked to one another by at least one common tensioning means 29, for example at least one circulating chain, which runs through these machine units (FIG. 1). The direction of circulation of the tensioning means 29 is indicated diagrammatically in FIG. 1 by a directional arrow. In a preferred configuration, the tensioning means 29 is formed by two mirror-symmetrically configured chains, which are driven synchronously by a drive 32, in particular formed as an electric motor, via a number of, for example, two, shafts 31, each having a gear. Two of these shafts 31 are arranged at least at both deflection points of the chains, i.e., respectively at the ends of the conveying section through the production line 01 stretched by these chains. In the continuous dryer 17, rails 33 are preferably arranged, and each of these chains is supported on one of these rails 33, respectively via a laterally mounted rolling roll 36.

Figure 2 shows, by way of example, one of a number of metal sheet sheets 08, which are rectangular in shape and are usually flexible, to be transported one after the other along a transport path that runs through the production line 01. Each of these metal sheet sheets 08 has a length L in the transport direction T planned for the metal sheet 08 and a width B transverse to this transport direction T, the format of each metal sheet 08 being determined by the indication of the length L of the metal sheet 08 times the width B of the metal sheet 08.

Figure 3 shows, in a plan view, by way of example, one of the transport devices 09 arranged in at least two different machine units of the production line 01. Figure 4 shows, in a perspective view, one of these transport devices 09, for example arranged in a transport module 04.

Figure 5 shows the conveying device 09 in an enlarged plan view. In a preferred configuration, the conveying device 09 has at least one, preferably two, conveying belts 11 only in the central region M of the conveying device 09 extending along the conveying direction T of the metal sheet 08, the conveying belt or belts 11 being each formed in the form of an endless loop, for example as a flat belt made of a particularly flexible material. The flat belt, for example with a thickness of 1 mm to 5 mm, preferably about 2 mm, has a width B11 of, for example, 30 mm to 250 mm, preferably about 40 mm or 80 mm. The conveying device 09, for example formed in the shape of a table, preferably has a flat plate 12 (Figure 4), which is arranged stationary in the conveying plane of the metal sheet 08, the width B12 of the plate 12 extending transversely to the conveying direction T of the metal sheet 08 being at least as large as the width B of the largest format of the metal sheet 08 to be conveyed by the conveying device 09. The central region M of the conveying device 09, which is usually formed in a strip shape, extends with its short sides, for example, over up to 60%, preferably up to 30%, in particular 10% to 20%, particularly preferably about 15% of the width B12 of the plate 12 of the conveying device 09, of the width B12 of the plate 12 of the conveying device 09, and with its long sides extends along the conveying direction T of the metal sheet 08 to be conveyed. The plate 12 of the conveying device 09 has a length L12, which is preferably at least as large as the length L of the largest format of the metal sheet 08 to be conveyed by the conveying device 09.

Each conveyor belt 11 of the conveying device 09 is preferably arranged so that, wrapped around a deflection roll, the metal sheet 08, which is placed on the respective tension span of the conveyor belt 11 and is also, for example, held on the conveyor belt 11, can be conveyed along a linear conveying section relative to the stationary plate 12, which conveying section extends, for example, at least over the length L12 of the conveying device 09. The holding force required to hold the metal sheet 08 placed on the conveyor belt 11 is, for example, achieved by suction, the required suction being generated, for example, by the connection of a suction box arranged under the plate 12 of the conveying device 09 and a suction pump connected to the suction box. The suction pump is preferably switched on and/or off, or at least can be switched on and/or off, as required. Alternatively or additionally, a magnetic holding means may be provided to hold the metal sheet 08 placed on the conveyor belt 11, which preferably can also be switched on and off. The conveyor device 09 may have a plurality of, for example two, conveyor belts 11 arranged parallel to each other.

In the production line 01, preferably at least two of these conveying devices 09 are arranged in different machine units, each separately from the other, i.e. as independent components, and one of these conveying devices 09 is arranged in particular in the loading station 02 or in the unloading station 07. The conveyor belts 11 of the conveying devices 09 are driven by an electric drive 16 in such a way that the conveyor belts 11 arranged in the different conveying devices 09 are preferably synchronized with each other in terms of their respective circulation speeds, so that the metal sheet sheets 08 conveyed by these conveyor belts 11 are conveyed at the same numerically linear speed, except for small permissible tolerances, and the metal sheet sheets 08 are held on the conveyor belts 11, for example, by suction and/or magnetically. In this case, the conveying of the sheet metal sheets 08 resting on the conveyor belt 11 is carried out in the conveying plane of the sheet metal sheets 08, i.e. in particular with respect to the plate 12 of the conveying device 09, in each case essentially floating on an air cushion, so that it is largely friction-free, but at least very low friction and practically slip-free, since each sheet metal sheet 08 is only in contact with the relatively thin conveyor belt 11. The respective electric drives 16 of the conveying devices 09 are, for example, respectively configured as electric motors and are preferably respectively at least information-technically connected to a machine control 34 arranged above the individual machine units of the production line 01, for example to a central control of this production line 01.

The conveyor belts 11 arranged in the different conveying devices 09 are preferably driven by the respective electric drives 16 of the conveying devices 09 so that they circulate, for example continuously, in particular at a uniform speed. Alternatively, the conveyor belts 11 may be driven in a clocked manner. The conveyor belts 11 of the conveying devices 09 arranged, for example, in the loading station 02 may preferably be driven in a clocked manner by the machine control 34 and/or the sheet metal sheets 08 placed on the conveyor belts 11 of this conveying device 09 may be driven in a momentary braking manner with respect to the linear speed of the sheet metal sheets 08, whereas the conveyor belts 11 of the conveying devices 09 arranged, for example, in the unloading station 07 may preferably be driven in a clocked manner by the machine control 34 and/or the sheet metal sheets 08 placed on the conveyor belts 11 of this conveying device 09 may be driven in a momentary acceleration manner with respect to the linear speed of the sheet metal sheets 08. The synchronous operation of the conveyor belts 11 arranged in the different conveying devices 09, and therefore in particular of the sheet metal sheets 08 held by these conveyor belts 11, is advantageous in particular during start-up or shutdown of the machine units of this production line 01. For the unhindered transport of the sheet metal sheets 08 through the production line 01, the synchronous operation of the conveyor belts 11 arranged in the different conveying devices 09, and therefore also of the sheet metal sheets 08, must be ensured, particularly in the transitions between the machine units of this production line 01 that are involved in the production process.

The plate 12 of the conveying device 09 has, on both sides of the respective central region M of the conveying device 09, a belt-free edge region R1; R2, which preferably have the same width extending transversely to the conveying direction T of the sheet metal sheets 08 and are preferably arranged symmetrically with respect to the longitudinal extension of the conveying device 09. At least in the belt-free edge region R1; R2, for example, but additionally also in the central region M of the conveying device 09, at least one nozzle field 13 is formed, which nozzle field 13 each has a number of nozzles 14. The nozzles 14 arranged there are operated in such a way that the nozzles 14 blow air onto the underside of the sheet metal sheets 08, which are placed on at least one conveyor belt 11 of the conveying device 09 and are held on one or more of the conveyor belts 11, respectively, to form an air cushion. In one advantageous configuration, at least some of the nozzles 14 of the nozzle field 13 are formed, for example, as Venturi nozzles. In each nozzle field 13, for example, a first subset of the individual nozzles 14 and/or a second subset of the individual nozzles 14 are arranged such that the first subset of the nozzles 14 direct the blow air obliquely outward at an acute angle in the conveying direction T of the sheet metal sheet 08, i.e., toward the nearest edge of the conveying device 09 extending along the conveying direction T of the sheet metal sheet 08, and/or the second subset of the nozzles 14 direct the blow air vertically upwards.

6 shows an exemplary perspective view of a loading station 02 arranged in a production line 01 with a transport module 04 directly preceding it in the transport direction T of the sheet metal sheets 08. In this embodiment variant, both the loading station 02 and the transport module 04 each have their own frame 19; 21, and these two machine units are seamlessly joined to one another, so that the frame 21 of the loading station 02 and the frame 19 of the transport module 04 form a common joint. The transport module 04 has a transport device 09, for example with a plate 12, on which the sheet metal sheets 08 to be transported in the transport direction T, indicated diagrammatically by a directional arrow, are illustrated in their largest and smallest format. The metal sheet 08 is additionally placed only on the conveyor belt 11, which extends along the conveying direction T and wraps around the deflection roll, and is additionally held in a floating manner above the plate 12 by air cushions generated by nozzles 14. In contrast to the configuration of the conveyor module 04 according to Figures 3 and 4, the embodiment variant of the conveyor device 09 shown in Figure 6 has only a single conveyor belt 11 arranged longitudinally in the center of the plate 12.

7 shows a plan view of the loading station 02 shown in FIG. 6. The loading station 02 has a conveying device 09 that feeds the metal sheet 08, which is laid flat in the conveying plane of the conveying device 09, to the continuous dryer 17, and the loading station 02 has at least one wire frame 22, each of which can be rotated, typically in a circular manner, about a rotation axis 23 extending transversely to the conveying direction T of the metal sheet 08 to be conveyed. In this case, each of the wire frames 22 is designed to pass from bottom to top during a pivoting movement through the conveying plane of the metal sheet 08, which is laid flat in the conveying plane, and to vertically raise the metal sheet 08, which is laid flat and is to be conveyed through the continuous dryer 17, from the previous conveying plane of the metal sheet 08, by this pivoting movement. In a preferred configuration of the loading station 02, two parallel, for example clock-controlled and brake-driven conveyor belts 11 are arranged in the central region M of the conveying device 09 of the loading station 02, which hold the flat-lying sheet metal sheets 08 thereon, for example by suction and/or magnetic holding forces, and convey the flat-lying sheet metal sheets 08, for example, until they strike a stop 24 extending transversely to the conveying direction T of the sheet metal sheets 08 to be conveyed, which stop 24 is formed, for example, by a rubber buffer arranged on the pivot axis 23. The conveying device 09 of the loading station 02 preferably also has two respective belt-free edge regions R1; R2, in which nozzle fields 13 are formed, as explained above in connection with FIG. In each nozzle field 13, a number of nozzles 14 are arranged in order to form an air cushion bearing the sheet metal sheet 08 lying flat on the conveyor belt 11, with, for example, a first subset of the nozzles 14 respectively ejecting the blowing air obliquely outward at an acute angle in the conveying direction T of the sheet metal sheet 08 and/or, for example, a second subset respectively ejecting the blowing air vertically upwards towards the underside of the sheet metal sheet 08 lying on the conveyor belt 11. On each wire frame 22, for example laterally, an arm 26 is arranged which projects respectively towards the nearest edge of the conveyor device 09 extending in the conveying direction T of the sheet metal sheet 08, and which engages in each of the recesses 27 provided in one of the edge regions R1; R2. In this case, in order to avoid the metal sheet 08 to be transported by the transport device 09 getting stuck, these notches 27 preferably have a slope 28, for example in the form of at least one edge that extends accordingly, that extends at an acute angle in the direction opposite to the transport direction T of the metal sheet 08 toward the nearest edge of the transport device 09 that extends along the transport direction T of the metal sheet 08.

8 shows a plan view of an unloading station 07 arranged in the production line 01 by way of example. The conveying device 09 of the unloading station 07 is constructed similarly to the conveying device 09 of the loading station 02, so that in the following the same parts are also designated by the same reference numerals. The unloading station 07 also has at least one wire frame 22, each of which can be rotated, as a rule, in a circular manner about a rotation axis 23 extending transversely to the conveying direction T of the sheet metal sheets 08 to be conveyed, and each of the wire frames 22 is formed so that during its pivoting movement it passes from top to bottom through the conveying plane of the sheet metal sheets 08 to be conveyed by the conveying device 09, and by this pivoting movement it lays down flat each one of the sheet metal sheets 08 that have been vertically erected and conveyed through the continuous dryer 17 into the conveying plane of the conveying device 09 of the unloading station 07. In a preferred configuration of the unloading station 07, two transport belts 11 are arranged in the central region M of the transport device 09 of the unloading station 07, which are driven parallel to one another, for example at equal speed or in a clocked and accelerated manner, and which hold the sheet metal sheets 08 lying flat on them, for example by suction and/or magnetic holding forces. The transport device 09 of the unloading station 07, as explained above in connection with FIG. 5, preferably also has two respective belt-free edge regions R1; R2, in which nozzle fields 13 are respectively formed. In each nozzle field 13, a number of nozzles 14 are arranged in order to form an air cushion bearing the sheet metal sheet 08 lying flat on the conveyor belt 11, with, for example, a first subset of the nozzles 14 respectively ejecting the blowing air obliquely outwards at an acute angle in the conveying direction T of the sheet metal sheet 08 and/or, for example, a second subset respectively ejecting the blowing air vertically upwards towards the underside of the sheet metal sheet 08 lying flat on the conveyor belt 11. On the wire frame 22, for example laterally, arms 26 are arranged which extend respectively towards the nearest edge of the conveyor device 09 in the conveying direction T of the sheet metal sheet 08, and which engage in each case in a recess 27 provided in one of the edge regions R1; R2. In this case, these notches 27 preferably have a slope 28 extending at an acute angle in the conveying direction T of the metal sheet 08 toward the nearest edge of the conveying device 09 extending along the conveying direction T of the metal sheet 08, for example in the form of at least one correspondingly extending edge, in order to avoid jamming of the metal sheet 08 to be conveyed by the conveying device 09.

In summary, a production line 01 for processing metal sheet 08 and a method for operating said production line 01 are obtained, which has a number of different machine units, at least one of which is formed as a continuous dryer 17. The continuous dryer 17 is formed in such a way that the metal sheet 08 to be dried passes through it vertically standing and usually spaced apart from one another, and the continuous dryer 17 is preceded by a loading station 02 for vertically standing the metal sheet 08 lying flat in the conveying plane of the conveying device 09, and is followed by an unloading station 07 for laying down the metal sheet 08 conveyed vertically standing through the continuous dryer 17 flat in the conveying plane of the conveying device 09. The distance between adjacent metal sheet 08 conveyed vertically standing through the continuous dryer 17 is only a few centimeters, for example 1 cm to 5 cm, in particular less than 3 cm. At least one surface, i.e. one or both sides, of each of the sheet metal sheets 08 to be dried in the continuous dryer 17 has previously been coated with at least one printing fluid in at least one machine unit formed as a sheet metal printing machine 03 and/or in at least one machine unit formed as a sheet metal painting machine 06. The printed and/or painted sheet metal sheets 08 are fed one after the other to the continuous dryer 17 and are raised vertically in the loading station 02 from the position in which the sheet metal sheets 08 lie flat in this production line 01 or else in the conveying plane of the sheet metal sheets 08 before feeding the sheet metal sheets 08 to the continuous dryer 17. Vertical standing here refers to, for example, standing of the individual metal sheet 08, which has previously been laid flat in the conveying plane of the respective conveying device 09, with a tolerance of less than ±30°, preferably less than ±15°, relative to the vertical line, which is preferably relative to the conveying plane of the respective conveying device 09. After the metal sheet 08 has been vertically stood and conveyed through the continuous dryer 17, the metal sheet 08 is then individually lowered back down in succession in the unloading station 07 into the conveying plane of the conveying device 09. In the production line 01, between the continuous dryer 17 and the unloading station 07, in the conveying direction T of the metal sheet 08 to be processed, a cooling zone 18 (FIG. 1), for example in the form of a cooling device, is formed, by which the metal sheet 08, which has been strongly heated during the passage through the continuous dryer 17, can be cooled to a significantly lower temperature.

In a preferred embodiment, at least two machine units of the production line 01 are each formed in a separate frame 19; 21. At least two of these machine units each have at least one conveyor device 09, which conveys at least one sheet metal sheet 08, which is placed flat in the respective conveying plane, and each of these conveyor devices 09 arranged separately from one another has at least one conveyor belt 11 for conveying the sheet metal sheet 08. The conveyor belts 11 of the conveyor devices 09 are each driven preferably by an electric drive 16, in particular such that the conveyor belts 11 arranged in the different conveyor devices 09 are each synchronized with one another in terms of their respective circulation speeds, so that the sheet metal sheets 08 conveyed by these conveyor belts 11 are each conveyed at least numerically approximately the same, i.e. with the exception of small permissible tolerances, at the same linear speed. In the conveying plane of the metal plate sheets 08 placed flat on the conveying belt 11, an air cushion is preferably formed below these metal plate sheets 08, and these metal plate sheets 08 are arranged in a floating manner by the air cushion in the conveying plane of the metal plate sheets 08.

The machine units of the load station 02, the continuous dryer 17, the cooling zone 18 and the unload station 07, which are arranged in succession in the conveying direction of the metal sheet 08 to be processed or processed in the production line 01, are always linked to one another, in particular not only by the functional, i.e. control-technical, linkage of the conveying device 09 in question, but also physically, i.e. mechanically, by at least one tensioning means 29 provided for the conveying of the metal sheet 08, for example preferably in the form of at least one chain running through all these machine units. In this case, the at least one tensioning means 29 passing through the machine units acts on the pivotable wire frame 22 of the load station 02 as well as on the pivotable wire frame 22 of the unload station 07, so that the connection of the wire frame 22 with the tensioning means 29 is performed, which has, for example, at least one connecting element 37 (FIG. 1), to which the respective wire frame 22 is attached during the connection. At least one tensioning means 29 passing through the machine unit is thereby configured to act on the pivotable wire frame 22 of the loading station 02 as well as on the pivotable wire frame 22 of the unloading station 07 and to form a connection of the wire frame 22 with the tensioning means 29. The circulation speed of the tensioning means 29 passing through the machine unit and the respective linear speeds of the conveyor belts 11 conveying the sheet metal sheets 08 in the respective conveyor devices 09 of the production line 01 are adjusted to one another, in particular synchronized to one another, in particular by the machine control 34.

In particular, when the production speed is high, i.e. several thousand sheet metal sheets 08 per hour, for example at least 6,000 sheet metal sheets 08 per hour, and/or when the format of the sheet metal sheets 08 to be processed in the production line 01 is large, for example more than 700 mm x 1,000 mm, and/or when the sheet metal sheets 08 have a small sheet metal thickness, for example less than 0.3 mm, the sheet metal sheets 08 are subjected to increased acceleration forces at the moment when they are lifted by the respective wire frames 22 of the conveying device of the loading station 02. This acceleration force causes the corners of the sheet metal sheets 08, which are not resting on the respective wire frames 22 in the area of the rear edge of the sheet metal sheets 08 lifted by the wire frames 22 and which are unstable under the abovementioned circumstances, to bend downwards according to gravity as a result of the moment of inertia and thus reach the area of the conveying path, in particular the area of the following sheet metal sheets 08. The corners of the lifted sheet metal 08 are not supported in this area by the respective wire frames 22 of the transport device of the load station 02 and may therefore sag. This may result in a collision with the front edge of the sheet metal 08 directly following the sheet metal 08 that is about to be lifted by the respective wire frame 22, which may result in production interruptions and/or rejection of the sheet metal 08 in the production line 01.

In order to avoid this potential operational problem, a method is proposed for operating a production line 01 for processing metal plate sheets 08, the production line 01 having a metal plate printing machine 03 and/or a painting machine 06, in which a loading station 02 is arranged after the metal plate printing machine 03 and/or the painting machine 06 in the conveying direction T of the metal plate sheets 08, and immediately after the loading station 02 a continuous dryer 17 for drying the printed and/or painted metal plate sheets 08 is arranged. In this case, the loading station 02 has a number of wire frames 22 which each rotate around a rotation axis 23 extending transversely to the conveying direction T of the metal plate sheet 08 being transported, and these wire frames 22 are arranged one after the other so as to lift each of the metal plate sheets 08 which are supplied to the loading station 02 lying flat, individually, from the conveying plane of the metal plate sheets 08, and each of these wire frames 22 is formed so as to pass through the conveying plane of the metal plate sheets 08 in a circular manner from bottom to top within the area where these metal plate sheets 08 are each individually supplied to the loading station 02, and by this pivoting movement to stand up one of the metal plate sheets 08 which is to be transported through the continuous dryer 17 lying flat. The loading station 02 additionally has at least one nozzle field 13, each with a number of nozzles 14, for example in the edge region R1; R2 formed along the conveying direction T of the sheet metal sheet 08 in the conveying plane of the sheet metal sheet 08, the nozzles 14 arranged therein being operated such that the blow air from the nozzles 14 is blown, preferably vertically upwards, onto the underside of the sheet metal sheet 08. At least a partial subset of the nozzles 14 blowing the blow air, preferably vertically upwards, are operated in a clocked manner, and these clocked nozzles 14 are switched on to discharge the blow air during the reception and lifting of the sheet metal sheet 08 by the wire frame 22, and are switched off before the blow air of the nozzles 14 hits the front edge 46 of the sheet metal sheet 08 that is directly following the sheet metal sheet 08 that has just been received and lifted by the wire frame 22.

9 shows in a simplified cross-sectional view an arrangement of at least one nozzle 14 formed in the loading station 02, which is operated in a clocked manner and each blows out the blowing air preferably vertically upwards. Preferably, a plurality of such nozzles 14 are provided. In FIG. 9, the wire frame 22 of the conveying device of the loading station 02 is shown in three different positions which the wire frame 22 occupies during the pivoting movement of the wire frame 22 about the pivot axis 23. The sheet metal sheet 08 supplied to the loading station 02 is conveyed in the conveying direction T of the sheet metal sheet 08 by at least one conveyor belt 11 on which the sheet metal sheet 08 lies flat, preferably until the sheet metal sheet 08 reaches the stop 24 with the front edge 46 of the sheet metal sheet 08. In particular, at this point when the front edge 46 reaches the stop 24, the sheet metal sheet 08 is received by the wire frame 22 and pivoted upward from the conveying plane in which the at least one conveyor belt 11 lies. As a result, the metal plate sheet 08 is preferably raised at least approximately vertically from the previous conveying plane of the metal plate sheet 08 before being fed to the continuous dryer 17.

In a preferred embodiment, the nozzles 14, which each preferably blow the blowing air vertically upwards, are operated with a settable blowing pressure. The blowing pressure of the nozzles 14, which each preferably blow the blowing air vertically upwards, is set or at least settable, for example, depending on the production speed of the sheet metal sheets 08 to be processed in the production line 01 and/or depending on the format of the sheet metal sheets 08 to be processed in the production line 01 and/or depending on the sheet metal thickness of the sheet metal sheets 08 to be processed in the production line 01. In order to set the blowing pressure of the nozzles 14, which each preferably blow the blowing air vertically upwards, a throttle valve 38 is preferably provided, the output of which is connected to the nozzles 14 and the input of which is connected to a compressed air source 41, the flow cross section of which can be controlled, for example, remotely, in particular settable, for example, in the machine control 34 formed as the central control unit of the production line 01, and a pressure gauge 39.

The nozzles 14, which each preferably blow out vertically upwards, are switched on to deliver blow air, in particular only when the sheet metal sheets 08 are conveyed through the production line 01 at a production speed higher than a preset minimum speed. The nozzles 14, which each preferably blow out vertically upwards, are switched off, for example, until a preset minimum value for the production speed of the sheet metal sheets 08 to be processed in this production line 01 is reached and/or for sheet metal sheets 08 having a format smaller than a preset minimum format for the sheet metal sheets 08 to be processed in the production line 01 and/or for sheet metal sheets 08 having a sheet metal thickness larger than a preset minimum sheet metal thickness for the sheet metal sheets 08 to be processed in the production line 01. This makes it possible to ensure that the aforementioned operating mode of the production line 01 is activated only when an unstable corner of the sheet metal sheets 08 actually flexes. Thus, operational disturbances and/or interruptions in the production line 01 and/or production of defective sheet metal sheets 08 can be avoided. In addition, the solution described can be used for new production lines 01, as well as for retrofitting production lines 01 already in use at customer sites.

As already mentioned, even at a constant production speed, in the production line 01, interference effects, for example the changing traction behavior between each sheet metal sheet 08 to be transported and the at least one transport belt 11 carrying said sheet metal sheet 08, can cause the free distance between successively transported sheet metal sheets 08, i.e. the distance between the rear edge of a first sheet metal sheet 08 and the front edge 46 of a second sheet metal sheet 08 directly following the first sheet metal sheet 08, to change, resulting in a shift of the synchronization point. This means, in particular, that the position of the front edge of the sheet metal sheet 08 currently being fed to the load station 02 will also shift relative to the end of the wire frame 22 of the transport device of this load station 02, which is intended to receive the sheet metal sheet 08 currently being fed and which, due to the pivoting movement of the wire frame 22, moves to the area that is about to receive the sheet metal sheet 08 currently being fed to the load station 02, facing this sheet metal sheet 08. This is because all the sheet metal sheets 08 supplied to the loading station 02 must be reliably received by one of the wire frames 22, each of which rotates around a pivot axis 23, one after the other, and lifted in a timely manner as a result of the pivoting movement of each wire frame 22, after which the sheet metal sheets 08 directly following the one currently being lifted must enter the working area of another wire frame 22. Otherwise, an obstruction will occur during the transport of the sheet metal sheets 08, resulting in a production interruption in the production line 01.

To avoid this fault, it is proposed, as can be seen from FIG. 10, that a first detection device 42 and a second detection device 43 are provided in or adjacent to the load station 02, the first detection device 42 and the second detection device 43 being each connected in signal technology to a control unit 44, preferably digital. The first detection device 42 detects a first time point at which one of the wire frames 22 of the transport device of the load station 02 occupies a predefined rotation angle position relative to the transport plane of the sheet metal sheet 08, and the first detection device 42 transmits a first signal to the control unit 44, which is representative of the detected first time point. The first detection device 42 can be arranged in various positions in the load station 02, which is shown diagrammatically in FIG. 10 by a second alternative installation position. The second detection device 43 detects a second time point when a front edge 46 of the sheet metal sheet 08 currently being fed to the loading station 02 reaches a predetermined position, which in the conveying plane of the sheet metal sheet 08, in the conveying direction T of the sheet metal sheet 08, is in front of an end of the wire frame 22 facing the sheet metal sheet 08, on which the sheet metal sheet 08 is intended to be received, and the second detection device 43 transmits a second signal representative of the detected second time point to the control unit 44. The control unit 44 is formed to determine an actual value of the time difference ΔT between the first and the second time points, to compare this actual value with a predetermined, preferably stored, target value for the time difference ΔT, and to determine a deviation of the actual value from the target value, the control unit 44 reporting a deviation of the actual value from the target value outside an acceptable tolerance range and/or displaying it on the display device 48, for example as an image and/or as a numerical value. The control unit 44 may be formed, for example, integrated in the machine control 34 of the production line 01. The first detection device 42 and the second detection device 43 are preferably each formed as a sensor that operates in a contactless manner.

In a preferred embodiment, a drive 47, for example an electric motor, is provided which is connected to the control unit 44 in a signal-technical manner and drives the pivoting movement of the wire frame 22 around the pivot axis 23, and which is configured such that, if the deviation of the actual value from the setpoint is outside the permissible tolerance range, the drive 47 is controlled so that the wire frame 22, which is to receive the next sheet metal sheet 08 fed to the loading station 02, is pivoted into the conveying plane of the next sheet metal sheet 08 at a time when the actual value of the time difference ΔT for this next sheet metal sheet 08 again lies within the permissible tolerance range. The permissible tolerance range is, for example, in the single-digit percentage range from the setpoint or less. In a particularly preferred embodiment, the drive 47 for pivoting the wire frame 22 about the pivot axis 23 is identical to the drive 32 for driving the tensioning means 29, which is arranged to pass through at least the load station 02 and the continuous dryer 17 downstream of the load station 02. This last configuration is particularly advantageous when the tensioning means 29 is designed to act on the pivotable wire frame 22 of the load station 02 and to form a preferably mechanical connection of the wire frame 22 with the tensioning means 29.

The control unit 44 may be configured to determine a number of actual values for the time difference ΔT between the first and second time points and to filter out invalid actual values before comparing the actual values with a predefined target value for the time difference ΔT. The control unit 44 may also preferably be configured to act on a component of the production line upstream of the drive 47, such as the loading station 02 or the painting machine 06, or on a virtual drive axis acting on a number of machine units of the production line.

The described solution facilitates setting the optimal synchronization point for the feeding of the sheet metal sheets 08 to the loading machine 02 when production conditions change. The solution also helps to avoid collisions of the sheet metal sheets 08 with the wire frame 22, which in turn avoids production interruptions and rejects of the sheet metal sheets 08. Moreover, the solution can be retrofitted to existing installations.

As already mentioned, a point in the production process that is unfortunately very prone to failures is present in the production line 01 at the loading machine 02 that precedes the continuous dryer 17, since each sheet metal sheet 08 that is conveyed through the production line 01 must be received in time by one of the wire frames 22 in the loading machine 02 and lifted up before the next sheet metal sheet 08 can enter the pivoting area of the wire frame 22. If this does not happen, at least one of the sheet metal sheets 08 following the one that is just received will hit the end of the wire frame 22 that received the preceding sheet metal sheet 08, facing the front edge of the said following sheet metal sheet 08. Unfortunately, such a collision, and therefore a failure, can occur during the production process of this production line 01, even when the synchronization point is optimally set for the preceding sheet metal printing machine 03 or sheet metal painting machine 06.

At the same time, in the pivoting area of each wire frame 22 of the loading machine 02, relatively high forces act on the wire frame 22, each of which is made flexible due to its delicate structure. As a result of the wire frames 22 being made flexible in this way, it may happen that one of these wire frames 22, which would normally rotate around the pivot axis 23, remains in one position, specifically in the conveying plane of the metal sheet 08, in the position in which it is located at the moment when it receives the metal sheet 08 supplied to the loading machine 02. As already mentioned, this may result in a collision of the metal sheet 08 and thus in a disruption during the production process of the production line 01.

One cause of delayed lifting of a sheet metal sheet 08 accommodated by just one of the wire frames 22 can be a slight bending of some of the wire frames 22. A slight play of the wire frames 22 as a result of wear or manufacturing inaccuracies in the connecting elements 37, for example in the form of receiving holes, of the tensioning means 29, which is arranged as a conveying chain and runs through the loading machine 02 and the continuous dryer 17 downstream of the loading machine 02, can also cause delayed lifting of individual wire frames 22. Likewise, a slight unevenness in the guiding or deflecting parts of the tensioning means 29 can cause the lifting of the wire frames 22 to be performed unevenly and with a jerky motion, and thus the individual sheet metal sheets 08 to be lifted late. The causes mentioned for operational disturbances are particularly evident when sudden load changes and loads act on the wire frames 22 as well. This may be the case due to the additional weight of the contained metal sheet 08 and, therefore, the adverse acceleration forces on the load machine 02.

At high production speeds, thousands of sheet metal sheets 08 per hour, for example at least 6,000 sheet metal sheets 08 per hour, the forces acting on the wire frame 22 will naturally rise for a short time at the time of the placement of these sheet metal sheets 08, as well as when the sheet metal sheets 08 are heavy, for example with a mass of more than 2 kilograms. This will cause elastic deformation of the flexible wire frame 22 and subsequently mechanical vibrations of the wire frame 22. In the worst case, these vibrations can damage the freshly printed and/or painted surfaces of these sheet metal sheets 08, respectively. At the same time, when the speed is higher, the time available for the loading process will be shorter, which will further intensify the problem of deformation of the flexible wire frame 22 and/or the resulting vibrations.

In order to improve the functional reliability of the loading machine 02 and thus ensure fault-free operation of the production line 01, it is proposed to provide a lifting device in the loading machine 02 for the wire frame 22 of the loading machine 02. This lifting device has the advantage that it supports the flexible wire frame 22 when lifting the received metal sheet 08, respectively, and takes up part of the acceleration forces acting on the wire frame 22, thus at least to a large extent preventing elastic deformation of the wire frame 22 and mechanical vibrations of the wire frame 22. Such a lifting device allows the weight of the wire frame 22 to be further reduced, which ultimately contributes to the energy savings that can be achieved in the continuous dryer 17.

As can be seen from FIG. 11, the lifting device, which assists in lifting the metal sheet 08 received by the wire frame 22, is in a first configuration formed, for example, by clock-controlled compressed air nozzles 49, which are arranged in the loading machine 02 below the conveying plane of the metal sheet 08 to be fed, i.e. fed to the loading machine 02, and are operated to blow air onto the underside of the metal sheet 08 to be lifted, preferably vertically upwards with short pressure surges, at the moment when the metal sheet 08 is received by the wire frame 22. This configuration of the lifting device certainly does not act directly on the wire frame 22, but only indirectly, but assists in lifting the metal sheet 08.

A second configuration of the lifting device is also shown by way of example in FIG. 11 and comprises, for example, clocked electromagnets 51 arranged close to and above the conveying plane of the sheet metal sheets 08 to be fed, in particular in the region of at least one spacer 52 arranged at the end of each wire frame 22 away from the pivot axis 23. These electromagnets 51 are clocked and switched by a control unit 53 and support the wire frame 22 by means of a magnetic force that attracts the wire frame 22. These clocked electromagnets 51 may alternatively be arranged below the conveying plane of the sheet metal sheets 08 to be fed and act to support the wire frame 22 by means of a magnetic force that pushes it away. The control unit 53 for switching the electromagnets 51 is formed, for example, integrated in the machine control 34 of the production line 01.

In a third configuration of the lifting device, as exemplarily shown in FIG. 12, at least one cam 54, for example rotating, is provided above the conveying plane of the metal plate sheet 08 to be fed, and the cam 54 mechanically lifts the wire frame 22, and the cam 54 is periodically pivoted outward while the metal plate sheet 08 enters the loading machine 02.

According to a fourth configuration, shown by way of example only as a sketch in Figures 13a (longitudinal section) and 13b (cross section) and Figures 14a (longitudinal section) and 14b (cross section), respectively, the lifting device is formed as a lifting device, which is arranged in the loading machine 02 below the conveying plane of the fed metal sheet 08 and lifts at least one of the multiple longitudinal rods 59 or longitudinal beams 59 of the wire frame 22 in a form-locking manner, preferably in the central area. The lifting device can be formed, for example, in the form of a lever 57 which is periodically moved, in particular provided with a roll 56 at its free end, and which rotates about a rotation axis 61, preferably in the conveying direction T of the sheet metal sheet 08, or a tappet 58 which is moved obliquely with respect to the underside of the sheet metal sheet 08 to be lifted by the wire frame 22 in question, and which is also provided with, for example, a roll 56 at its free end, preferably with a periodic transverse movement of the lever 57 or tappet 58 transverse to the conveying direction T of the sheet metal sheet 08, so that the lever 57 or tappet 58 can be moved out of the pivoting region of the following wire frame 22 after lifting the currently lifted wire frame 22. The periodic axial transverse movement of the lever 57 is shown diagrammatically in FIG. 13b by a double arrow. In FIGS. 14a and 14b, the lifting movement of the tappet 58 is shown diagrammatically by a double arrow, respectively.

The main advantage of the lifting device described above is that the flexible wire frame 22 does not need to apply the force to lift the metal plate sheet 08 alone.

In order to make the transport of the metal sheet 08, particularly through the continuous dryer 17, more efficient, in the production line 01 for processing the metal sheet 08, the load station 02 is formed so that the metal sheet 08 supplied to the load station 02 in succession is individually placed in one of the multiple wire frames 22 provided separately in the load station 02, and the pulling means 29 passing through at least the continuous dryer 17, which circulates endlessly, is provided with at least one connecting element 37, and the connecting element 37, which is formed, for example, as a hanging loop, is arranged so that one of the multiple metal sheet sheets 08 is held. The tension means 29 is formed so as to act on the wire frame 22 accommodated therein and to form a connection of the wire frame 22 with the tension means 29, and in the proposed more efficient configuration of the production line 01, it is proposed that in the operating state in which the wire frame 22 passes through the continuous dryer 17, the wire frame 22 accommodated therein with the sheet metal sheets 08 is suspended and connected to the lower span of the tension means 29 and is arranged to be supported at its lower end on a stand 62, the wire frame 22 thus suspended and supported being arranged in an inclined position with an angle W in the range of 10° to 45° with respect to the vertical, the inclination of the suspended and supported wire frame 22 being formed so as to vary along the conveying section through the continuous dryer 17 in the operating state in which the wire frame 22 passes through the continuous dryer 17, and may take different angles W at different positions of the conveying section. The wire frame 22 to be connected to the lower span of the tensioning means 29 in a suspended manner has, for example, a receiving pin that is engaged in the hanging loop of the tensioning means 29. The racks 62 supporting the lower ends of the wire frames 22, on which the respective sheet metal sheets 08 are accommodated, are formed, for example, as fixedly mounted rails or as carrier systems, for example in the form of belts, which preferably rotate synchronously with the tensioning means 29. The inclined position of the wire frames 22 arranged in a suspended and supported manner ensures the stability of the sheet metal sheets 08 thus transported, in particular in that these sheet metal sheets 08 do not sink or bulge in the respective inclined position. The proposed particularly efficient design of the production line 01 is exemplarily shown in FIG. 15.

This configuration of the production line 01 has the advantage that the wire frame 22 suspended and connected to the lower span of the tensioning means 29, unlike the wire frame 22 formed to rotate about the pivot axis 23, can be made very delicate, so that only a very low mass needs to be moved, which leads to energy savings during the operation of the production line 01. Furthermore, when the metal sheet 08 supplied to the load station 02 is transported by the wire frame 22 suspended and connected to the lower span of the tensioning means 29, unlike the wire frame 22 formed to rotate about the pivot axis 23, the transport speed of the metal sheet 08 does not need to be completely braked before the metal sheet 08 is received by the wire frame 22, so that the production line 01 can be operated with a higher throughput of the metal sheet 08. Furthermore, the wire frame 22 suspended and connected to the lower span of the tensioning means 29 reduces the risk that the metal sheet 08 conveyed by the wire frame 22 will cause damage to the printed and/or painted surface, for example due to vibration, in the contact area between the metal sheet 08 and the wire frame 22.

As already mentioned, the load station 02 for loading the printed and/or painted metal sheet 08 onto the continuous dryer 17 is arranged immediately before the continuous dryer 17 in the conveying direction T of the metal sheet 08. Furthermore, immediately after the continuous dryer 17, an unload station 07 for unloading the metal sheet 08 conveyed through the continuous dryer 17 is preferably arranged, which is configured to release the wire frame 22 conveying the metal sheet 08 from the lower span of the tensioning means 29. Furthermore, in a preferred development, a transport mechanism 63 independent of the tensioning means 29 is provided, which is configured to transport the wire frame 22 released and thus removed from the lower span of the tensioning means 29 in the unload station 07 back to the load station 02 individually, in a stack or in a shifted overlapping state. In FIG. 15, the return transport of the wire frame 22 that has been released and unloaded in the unloading station 07 is shown diagrammatically by directional arrows. In the unloading station 07, the wire frame 22 that has been transported through the continuous dryer 17 is automatically released from the lower span of the tensioning means 29 and guided back to the loading station 02 by the transport mechanism 63. In the unloading station 07, the sheet metal sheet 08 is selectively lowered with the printed and/or painted surface of the sheet metal sheet 08 facing up or down, from where it can be further transported in the production line 01.

The tensioning means 29 that suspends and transports the wire frame 22 is formed, for example, by two chains arranged in mirror symmetry, and these chains are driven synchronously via a number of shafts 31 each having gears, and two of these shafts 31 are each located at the ends of the transport section through the production line 01 that is stretched by these chains.

In a particularly efficient configuration of the production line 01, as shown by way of example in FIG. 16, at least two tensioning means 29 are provided, arranged vertically one above the other and each passing through at least the continuous dryer 17, the tensioning means 29 being arranged in different planes, preferably extending horizontally through the continuous dryer 17, at least one of the tensioning means 29 having a platform 62 supporting the wire frame 22 suspended and transported by the tensioning means 29. In this configuration of the production line 01, the load station 02 has a switch 64, which is configured to selectively supply the sheet metal sheets 08 supplied to the load station 02 to one of the tensioning means 29 arranged vertically one above the other. The switch 64 is, for example, arranged before the load station 02 or is configured as a component part of the load station 02. The allocation of the metal sheet 08 to the individual tensioning means 29 arranged vertically one above the other, which can be achieved by the splitter 64, is shown diagrammatically by arrows in FIG. 16. This special configuration of the continuous dryer 17 with at least two tensioning means 29 arranged vertically one above the other has the advantage that the length of the conveying section through the continuous dryer 17 can be shortened compared to a configuration with tensioning means 29 only in a single plane that runs through the continuous dryer 17, particularly horizontally.

01 Production line 02 Load station 03 Metal plate printing machine 04 Transport module 05 -
06 Metal plate painting machine 07 Unloading station 08 Metal plate sheet 09 Conveying device 10 -
11 conveyor belt 12 plate 13 nozzle field 14 nozzle 15 -
16 Drive unit 17 Continuous dryer 18 Cooling zone 19 Frame 20 -
21 Frame 22 Wire frame 23 Rotation axis 24 Stopper 25 -
26 Arm 27 Notch 28 Slope 29 Pulling means 30 -
31 Axis 32 Drive unit 33 Rail 34 Machine control unit 35 -
36 Rolling roll 37 Connecting element 38 Throttle valve 39 Pressure gauge 40 -
41 compressed air source 42 first detection device 43 second detection device 44 control unit 45 -
46 Front edge 47 Drive unit 48 Display device 49 Compressed air nozzle 50 -
51 electromagnet 52 spacer 53 control unit 54 cam 55 -
56 Roller 57 Lever 58 Tappet 59 Longitudinal rod; longitudinal beam 60 -
61 Rotation axis 62 Platform 63 Conveying mechanism 64 Switch B Width B11 Width B12 Width L Length L12 Length M Central region R1; R2 Edge region T Conveying direction W Angle

Claims (7)

A method of operating a production line (01) for processing metal sheets (08), comprising the steps of:
The production line (01) comprises:
A metal plate printing machine (03) and/or a coating machine (06),
a continuous dryer (17) for drying the metal plate sheet (08) printed by the metal plate printing machine (03) and/or coated by the coating machine (06);
having
a loading station (02) for loading the printed and/or painted metal sheet (08) onto the continuous dryer (17) is disposed immediately before the continuous dryer (17) in the conveying direction (T) of the metal sheet (08);
The loading station (02) has a plurality of wire frames (22) each rotating about a rotation axis (23) extending transversely to the conveying direction (T) of the conveyed metal sheet (08),
The wire frames (22) are arranged to lift each of the metal plate sheets (08) that are conveyed in a tandem from a conveying plane of the metal plate sheets (08),
each of the wire frames (22) is configured to pass through the conveying plane of the metal sheet (08) in a circular manner from bottom to top within the area where the metal sheet (08) is individually fed to the loading station (02), and this turning motion stands up one of the metal sheet (08) to be conveyed through the continuous dryer (17) lying flat;
The loading station (02) has a plurality of nozzles (14) in the conveying plane of the metal sheet (08);
The nozzles (14) are operated so that the blow air from each of the nozzles (14) is blown onto the lower surface of the metal plate sheet (08).
In the method,
operating at least a subset of said nozzles (14) each ejecting said blowing air in a clocked manner;
the clock-controlled nozzle (14) is switched on while the sheet metal (08) is received and lifted by the wire frame (22), and the clock-controlled nozzle (14) is switched off before the blowing air of the nozzle (14) hits the front edge of the sheet metal (08) that directly follows the sheet metal (08) being received and lifted by the wire frame (22). The method according to claim 1, characterized in that the nozzle (14) which blows out the blowing air in a clock-controlled manner is operated with a blowing pressure whose strength can be set. The method according to claim 2, characterized in that the strength of the blowing pressure of the nozzles (14) from which the blowing air is blown out in a clocked manner is set or at least can be set depending on the production speed of the metal sheet (08) to be processed in the production line (01) and/or depending on the format of the metal sheet (08) to be processed in the production line (01) and/or depending on the sheet metal thickness of the metal sheet (08) to be processed in the production line (01). The method according to claim 2 or 3, characterized in that a throttle valve (38) is provided to set the strength of the blowing pressure of the nozzle (14). 5. The method according to claim 4, characterized in that the throttle valve (38) is connected to a compressed air source (41) and is provided with a pressure gauge (39), and the flow cross section of the throttle valve (38) is remotely controlled and/or can be set in a machine control (34) of the production line (01). The method according to claim 1, 2 or 3, characterized in that the clock-controlled nozzle (14) is switched on to deliver blow air only when the sheet metal (08) is conveyed through the production line (01) at a production speed higher than a preset minimum speed. 4. The method according to claim 1, 2 or 3, characterized in that the clock-controlled nozzle (14) is switched off until a preset minimum value for the production speed of the sheet metal sheets (08) to be processed in the production line (01) is reached and/or for sheet metal sheets (08) having a format smaller than a preset minimum format for the sheet metal sheets (08) to be processed in the production line (01) and/or for sheet metal sheets (08) having a sheet metal thickness larger than a preset minimum sheet metal thickness for the sheet metal sheets (08) to be processed in the production line (01).

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