EP0698573B1 - Apparatus for conveying metal sheets - Google Patents

Description

The invention relates to a device for conveying Metal sheets, with a conveyor on which the metal sheets be promoted at a high speed, with a Removal device for removing a sheet of metal from the Conveyor device with means for checking the removed Sheet and with a sluice-in device for re-sluicing the removed sheet of metal into the conveyor.

The invention further relates to a device for conveying of sheet metal, with a conveyor on which the Metal sheets delivered at a first, high speed and with one behind the conveyor in the direction of transport arranged loading device for transfer the metal sheets from the conveying device to a drying device, that of the metal sheets with a second, lower one Speed will go through.

Finally, the invention relates to a device for conveying of sheet metal, with a conveyor on which the Removed metal sheets of a first, high speed and with one in the direction of transport in front of the conveyor arranged unloading device for transferring the Metal sheets from a drying device, from the metal sheets run at a second, lower speed became the conveyor.

From the document DE book "Der Blechdruck" by Klaus Matt, Polygraph Verlag Frankfurt am Main, 1983 are procedures and devices known for printing on sheet metal. In this context (Page 39, 83) a loading machine is also described, in which those brought up by the printing or painting machine, printed metal sheets by means of a loading device Dryer are supplied. For this purpose the sheet metal brought up by the printing machine magnetically braked and passed onto a wire frame, which the Panels swung into an almost vertical position and in this position at a much slower speed through the drying facility.

In another known device, one on one Stack of metal sheet to be put down by one at constant speed driven conveyor belt fed to a stacking table. After leaving the conveyor belt, the sheet metal hits against a resilient stop surface and is thereby on the Zero speed braked in the translatory direction and across the translational direction onto a stacking table stored.

This known device has the disadvantage that it is damage to the surface-treated in particular Sheet metal is coming. On the other hand, the reproducibility of the Braking very bad. As a result, those to be discarded encounter Metal sheets often at such a high speed against the Stop surface at the stacking table, that imprints of brake buffers or the like arise on the metal sheets.

From document EP 0 408 893 A1 there is a sheet deposit for rotary cross cutters known. The known device comprises a Conveyor, the arches at a certain speed approach promotes. The sheets leave the conveyor hill-like so that they go through a flight arch, whereby their rear edge hits a braking device. The Braking device has a certain braking speed circumferential run on which a suction box is assigned is. The trailing edge of the sheet appearing on the run held in place by the suction device and due to the lower speed compared to the conveyor the braking device braked so that a tray can be done on a stack. This known device does not allow a particularly high funding rate (sheets per unit of time), because the mostly not particularly stable trajectory of the arches allows only a small number per unit of time without it collisions, damage etc. occur. Moreover kick for example when the rear edge hits the braking device Relative movements between the bow and braking device, so that sensitive goods, e.g. freshly coated goods, either not supplied at all with such a known device can be or the risk of damage, scratches etc. subject to.

Document DE 23 48 320 B2 describes a device for batches Laying out individual sheets of equal length known. at this known device are at a distance of less than suction conveyor rollers arranged along a sheet length and with blown air Actuated floating slats for feeding the to be put down flexible sheets provided for a stacking table. Before the The sheets are deposited at a speed opposite the conveying speed lower peripheral speed driven Suction brake roller passed, where they then by sliding friction or Slip can be delayed to a depositing speed. in this connection it comes back to the problems already mentioned.

From document DE 90 07 362 Ul there is a sheet delivery on rotary printing presses known. The well-known sheet boom has via a braking device with a perforated band that with constant Speed is driven, namely with a lower Speed as the speed of the drop Arc. In this known device is a suction provided the end of the sheet on the conveyor belt.

From document DE 27 55 160 B2 there is a device for braking and overlapping those to be placed on a shelf as a stack Bow or bow packages known. In this known Device is provided a braking device, the suction force adjustable in proportion to the conveying speed of the sheets is. A braking device is a rigid one in the room Structures provided. It essentially consists of one stationary suction box over which the incoming sheets of paper fly loose. The sheets of paper are replaced by a Combination of blown air and suction air on the one hand in suspension held and braked on the other. Far upstream of the Braking device, a sensor is provided with which a slide is controllable to the suction openings of the suction box in time to open or close the funding. This has the Sinn, the approaching bow only at its rear end to apply vacuum and thereby brake. The approaching bow has namely with its front and middle Area of the braking device switched off at this time already happened before this is turned on then only to grasp the rear area of the sheet.

One method and one are known from document US Pat. No. 3,827,545 Device for adjusting the distance between individual flexible woven products, for example disposable diapers, are known. The known device comprises a first conveyor belt on which the products at a first speed and low Distance are conveyed one behind the other. The products then go through a space until they are between two rollers get a speed control unit in which they on a second, higher speed can be accelerated. To The products pass through a second free space then in the area of a second conveyor, like the first one Conveyor is formed, but at a higher speed running. The distance between the products is therefore on the second conveyor larger than on the first conveyor. For this is indicated that the conveyor, as well as the speed control unit also as a one-sided transport surface can be designed in the form of a belt through which a vacuum can be applied.

Document DE 41 19 511 A1 describes a braking device of sheets to be deposited on a stack, in particular Sheets of paper or cardboard, known. In this device the sheets of paper from a first conveyor at high speed approach promoted. The arches then fly over one Braking device which is provided with suction belts, the Suction belts at a certain distance one behind the other Have clamp legs. The upper run of the suction belt is inclined downwards for the transport direction of the paper sheets. The advancing sheets of paper fly with their front end over the upper run of the braking device while the rear end gripped and held by a clamp leg while the suction belt moves to a second, lower one Speed is slowed down. The back end of the arch is held by the clamp leg until the end of the upper run and then released automatically. The paper sheet flies now continue at a lower speed onto a discard pile.

From document EP 0 129 013 A1 is a folder with a Delay route known. The known apparatus includes in Direction of transport with three conveyors in a row an upper and a lower conveyor belt, between which Folded copies are encouraged. The fold copies will be first conveyed on the first conveyor at high speed and then handed over to the second sponsor, who Folded copies are slowed down and then towards the third conveyor handed over, which runs at lower speed.

The invention is therefore based on the object of devices of the type mentioned at the beginning, which allow Metal sheets can be handled without damage and with a high cycle rate.

a) eine Förderfläche, die von mindestens einem mit Ansaugöffnungen versehenen Saugriemen gebildet ist;

b) eine Antriebseinheit für den Saugriemen;

c) einen mit einer Unterdruckeinrichtung verbundenen Saugraum, der mit den Ansaugöffnungen kommuniziert;

d) einen Positionssensor zum Erkennen einer Leerstelle, die eine von der Entnahmevorrichtung entnommene Blechtafel auf der Fördereinrichtung hinterlassen hat;

e) Geschwindigkeitssensoren zum Erfassen der Geschwindigkeit des Saugriemens bzw. der Fördereinrichtung;

f) einer Steuerung, die beim Auftreten eines Initiator-Signals des Positionssensors

• einerseits den Saugriemen mit einer darauf aufliegenden Blechtafel aus dem Stillstand einer Warteposition auf die hohe Geschwindigkeit beschleunigt, derart, daß die Blechtafel mit der hohen Geschwindigkeit in die Leerstelle eingeschleust wird, und
• andererseits den Unterdruck im Saugraum so steuert, daß die Ansaugöffnungen im wesentlichen nur beim Beschleunigen des Saugriemens mit Unterdruck beaufschlagt werden, so daß die Blechtafel ohne Bewegung relativ zum Saugriemen beschleunigt wird.

In a device of the type mentioned at the beginning, this object is achieved according to the invention in that the infeed device comprises:

a) a conveying surface which is formed by at least one suction belt provided with suction openings;

b) a drive unit for the suction belt;

c) a suction chamber connected to a vacuum device and communicating with the suction openings;

d) a position sensor for recognizing an empty space which has left a sheet of metal removed by the removal device on the conveyor device;

e) speed sensors for detecting the speed of the suction belt or the conveyor;

f) a controller that when an initiator signal of the position sensor occurs

• on the one hand accelerates the suction belt with a sheet of metal lying thereon from the standstill of a waiting position to the high speed in such a way that the sheet of metal is introduced into the empty space at high speed, and
• on the other hand controls the negative pressure in the suction chamber so that the suction openings are only subjected to negative pressure essentially when the suction belt is accelerated, so that the metal sheet is accelerated relative to the suction belt without movement.

a) eine Ablagefläche zum Aufnehmen der Blechtafeln, die von mindestens einem mit Ansaugöffnungen versehenen Saugriemen gebildet ist;

b) eine Antriebsvorrichtung für den Saugriemen;

c) einen mit einer Unterdruckeinrichtung verbundenen Saugraum, der mit den Ansaugöffnungen kommuniziert;

d) einen Positionssensor zum Erkennen einer auf der Ablagefläche ankommenden Blechtafel;

e) Geschwindigkeitssensoren zum Erfassen der Geschwindigkeit des Saugriemens bzw. der Fördereinrichtung;

f) einer Steuerung, die beim Auftreten eines Initiator-Signals des Positionssensors

• einerseits den Saugriemen mit einer darauf aufliegenden Blechtafel von der hohen Geschwindigkeit im wesentlichen bis zum Stillstand abbremst, derart, daß die Blechtafel im Stillstand an einen nach oben schwenkenden Tragrahmen übergeben wird, und
• andererseits den Unterdruck im Saugraum so steuert, daß die Ansaugöffnungen im wesentlichen nur beim Abbremsen des Saugriemens mit Unterdruck beaufschlagt werden, so daß die Blechtafel ohne Bewegung relativ zum Saugriemen abgebremst wird.

In the case of a device of the type mentioned at the beginning, the object on which the invention is based is achieved in that the loading device comprises:

a) a storage surface for receiving the metal sheets, which is formed by at least one suction belt provided with suction openings;

b) a drive device for the suction belt;

c) a suction chamber connected to a vacuum device and communicating with the suction openings;

d) a position sensor for detecting a sheet of metal arriving on the storage surface;

e) speed sensors for detecting the speed of the suction belt or the conveyor;

f) a controller that when an initiator signal of the position sensor occurs

• on the one hand brakes the suction belt with a sheet of metal lying thereon from the high speed essentially to a standstill, in such a way that the sheet of metal is transferred to a support frame which pivots upwards when it is not moving, and
• on the other hand controls the negative pressure in the suction chamber so that the suction openings are only subjected to negative pressure essentially when the suction belt is braked, so that the metal sheet is braked relative to the suction belt without movement.

a) eine Ablagefläche zum Aufnehmen der Blechtafeln, die von mindestens einem mit Ansaugöffnungen versehenen Saugriemen gebildet ist, wobei die Blechtafeln mittels eines Tragrahmens im wesentlichen im Stillstand von oben auf dem Saugriemen abgelegt werden;

b) eine Antriebsvorrichtung für den Saugriemen;

c) einen mit einer Unterdruckeinrichtung verbundenen Saugraum, der mit den Ansaugöffnungen kommuniziert;

d) einen Positionssensor zum Erkennen einer auf der Ablagefläche ankommenden Blechtafel;

e) Geschwindigkeitssensoren zum Erfassen der Geschwindigkeit des Saugriemens bzw. der Fördereinrichtung;

f) einer Steuerung, die beim Auftreten eines Initiator-Signals des Positionssensors

• einerseits den Saugriemen mit einer darauf aufliegenden Blechtafel im wesentlichen vom Stillstand auf die erste, hohe Geschwindigkeit beschleunigt, und
• andererseits den Unterdruck im Saugraum so steuert, daß die Ansaugöffnungen im wesentlichen nur beim Beschleunigen des Saugriemens mit Unterdruck beaufschlagt werden, so daß die Blechtafel ohne Bewegung relativ zum Saugriemen beschleunigt wird.

Finally, the object on which the invention is based is achieved in a device of the type mentioned at the beginning in that the unloading device comprises:

a) a storage area for receiving the metal sheets, which is formed by at least one suction belt provided with suction openings, the metal sheets being deposited on the suction belt from above, essentially at a standstill, by means of a support frame;

b) a drive device for the suction belt;

c) a suction chamber connected to a vacuum device and communicating with the suction openings;

d) a position sensor for detecting a sheet of metal arriving on the storage surface;

e) speed sensors for detecting the speed of the suction belt or the conveyor;

f) a controller that when an initiator signal of the position sensor occurs

• on the one hand accelerates the suction belt with a sheet of metal lying thereon essentially from standstill to the first, high speed, and
• on the other hand controls the negative pressure in the suction chamber so that the suction openings are only subjected to negative pressure essentially when the suction belt is accelerated, so that the metal sheet is accelerated relative to the suction belt without movement.

According to the invention, the transition from a sheet of metal thus takes place the conveyor having a certain speed on the braking device without relative movements between the sheet of metal and the means of transport, so that - even with sensitive Surface coating - no damage occurs can. Only when there is no contact with the metal sheet more with the conveyor, the braking process carried out, in any case during braking by means of the holding device a fixation of the sheet on the conveyor surface the braking device, so that e.g. also one very strong braking is possible without relative movements. The Braking of the metal sheet is thus very different from that of State of the art - made such that the braking device initially the same speed as the conveyor then takes over the board and only then one The braking effect is developed by decelerating their conveying surface. This delay can go up to a desired speed, however, it can also be carried out to a standstill, depending on which device the metal sheets are to be fed to.

A sluice device according to the invention has proven to be particularly advantageous proved. Such a device is in Transport direction arranged behind a removal device. After through the removal device of a conveyor a sheet of metal, in particular for testing purposes, removed and after inspection of the infeed device was handed over this until the subsequent sheet metal is removed in one Waiting position on the conveying surface of the infeed device held. After removing the subsequent metal sheet, the Sheet metal held in waiting position by means of the conveying surface the sluice from zero speed to Conveyor speed V1 accelerates and can thus be transferred to the conveyor without slip. In that the sheet of metal is sucked against the conveying surface is, and is immovable relative to the conveying surface, can there is no damage during the acceleration process come. The accuracy mentioned at the beginning can also be mentioned become.

The device according to the invention can be further advantageous train and use as a loading device for a dryer. Again, the problem of damage-free takeover of the metal sheets delivered at high speed as well as a reproducible adjustable delay of Solved metal sheets. The delivered at high speed V1 Metal sheets are removed from the conveyor surface of the loading device, which is at an essentially the speed V1 corresponding speed, preferably exactly with the speed V1 is moved, picked up and against the conveying surface sucked. It is particularly advantageous that the delay the funding area only occurs when the taken over Sheet completely on the conveying surface of the loading device is, if there is a rear edge of the sheet metal taken over has left an upstream conveyor. In the loading device according to the invention, the panels are rotating Frame erected and slow through the dryer guided. It proves to be advantageous if the conveying surface and thus the sheet of metal sucked onto it onto a very low speed, preferably to a standstill, is delayed. In this case, the metal sheet is free of damage fed to the dryer. For this it is advantageous that the vacuum acting on the suction openings can be switched off is so that the sheet of metal under consideration is slightly off the conveying surface is removable. After removal of the metal sheet, the conveying area is accelerated back to their initial speed to take over the subsequent metal sheet.

An unloading device according to the invention proves to be equally advantageous, in the case of a drying device with the zero translational speed or slow speed delivered sheets of the essentially the same speed conveying surface of the unloading device taken over and on a conveyor speed a conveyor are accelerated. When accelerating sticks the sheet in the manner already described on the conveyor surface, which ensures a slip-free and therefore damage-free Acceleration is possible.

According to the invention it is further provided that the devices train that the suction ports are not open throughout Operation of the device are subjected to negative pressure, but that this is controlled separately with negative pressure become. The device is designed so that the suction openings synchronous with the acceleration or deceleration of the Conveying surfaces are subjected to negative pressure. With one Device the suction of the conveying surface is switched off, when there is no sheet metal on the conveying surface, for example in the deceleration movement of a sluice or during the acceleration movement of a loading device.

Further advantages, features and details of the invention result itself from the attached drawing and from the following Description of some advantageous embodiments of the device according to the invention.

Fig. 1

eine Seitenansicht einer erfindungsgemäßen Einschleusvorrichtung in schematischer Darstellung;

Fig. 2

eine Seitenansicht einer erfindungsgemäßen Beladevorrichtung in schematischer Darstellung; und

Fig. 3

eine Seitenansicht einer erfindungsgemäßen Entladevorrichtung in schematischer Darstellung.

Show it:

Fig. 1

a side view of a sluice device according to the invention in a schematic representation;

Fig. 2

a side view of a loading device according to the invention in a schematic representation; and

Fig. 3

a side view of an unloading device according to the invention in a schematic representation.

Fig. 1 shows an overall designated by the reference numeral 2 and above a conveyor 4 arranged sluice. In the direction of transport of the conveyor 4 in front of the infeed device one not shown in the figure Removal device arranged.

On the conveyor 4 are successive and from each other spaced tabular goods at high speed V1 in Fig. 1 transported from left to right. Of The removal device, not shown, is used from time to time Time, especially for testing purposes, one on the conveyor 4 transported table 6 removed, checked and the infeed device 2 fed. There is the removed board 6 in a waiting position until the next table is removed held and then on the speed V1 accelerated and fed to the conveyor 4.

The infeed device 2 comprises a conveying surface 8 which a suction belt 10 is formed.

The suction belt 10 is over two deflection rollers 12, 14 out and stands with a drive unit 16 in Drive connection. Next is one with the drive device 16 cooperating control 18 provided, which in turn signals from position or Speed sensors 20, 22, 24 receives. The sensor 24 detects an empty space a tablet removed from the removal device left on conveyor 4 and gives an initiator reference signal to the controller 18, which then in a predeterminable manner via the Drive device 16 the acceleration process of the suction belt 10 controls.

Suction openings 28 are formed in the suction belt 10, that communicate with a suction space 30, which in turn with a not shown, communicates a vacuum generating device. The infeed device 2 is designed that the suction openings 28 and the Suction chamber 30 can be acted upon by a vacuum are. It has proven to be advantageous that the panel 6 is only sucked in when this shortly thereafter from zero speed to one Speed, which is essentially the speed V1 corresponds to the conveyor 4, accelerates becomes.

The conveying surface 8 is in the case shown of four suction belts running parallel to each other 10 formed. Can continue outdoors not vacuumed rollers or sliding surfaces with if possible smooth surface can be provided. damage always occur in the area of strong force on, for example with relative movements, with acceleration- or delay operations. These powers are in the case shown in the area the suction belt 10 transmitted, where no relative movements occur.

After acceleration of the suction belt 10 to the unloading speed and after delivery of Table 6 the conveyor 4 effects the control 18 a delay via the drive device 16 the suction belt speed to a standstill of the suction belt 10. The suction of the Suction chamber 30 or the suction openings 28 switched off. However, it is also possible to Take over the following table the speed the suction belt 10 to a finite value reduce and only after takeover and relocation the following table into the waiting position until to brake to a standstill.

Through the separate drive device 16 and The controller 18 can accelerate and Delay processes with high reproducibility to adjust. The device is thus highest requirements with regard to clock accuracy the injection.

In Figure 2 is one with the reference number 34 designated loading device shown. The loading device 34 is in the transport direction arranged behind a conveyor 36, on the tabular goods 38 at high speed V1 delivered and from a conveyor area 40 of the loading device 34 are added. The conveying surface 40 is from a suction belt 42 formed with suction openings 43, which at the Takeover of the coming from the conveyor 36 Sheets run at the same speed V1. Immediately after taking over a board by a controller 44 and a drive device 46 of the suction belt 42 whose speed from V1 to a speed close to zero, preferably to a standstill, delayed. Meanwhile is the table to be delayed by using negative pressure acted upon suction openings 48 against the suction belt 42 sucked and therefore immovable on the suction belt 42 held. This can damage the board be delayed.

In the case shown, the loading device is for Loading a drying facility provided. Right away after the suction belt 42 with the on it sucked board has come to a standstill this panel from a support frame that swings upwards 52 lifted off and into an almost vertical Position pivoted, in which it is then with less Speed passes the drying device 50. If the suction belt 42 is not completely at a standstill is delayed, it proves advantageous if the support frame 52 even before the panel brought to a standstill by an attack, pivots through the plane of the suction belt 42 and the Chalkboard records. Then it becomes one Relative speed between the table in vacuumed state and the suction belt 42 avoided.

There are also cooperating with the controller 44 here Position or speed sensors 54 provided.

The conveying surface 40 of the loading device 34 comprises two inner suction belts running parallel to each other 42 and two further arranged outside Transport belts without suction openings. All straps are of a drive device 46 and temporarily driven synchronously with the conveyor 36.

Figure 3 shows an unloading device 60 for receiving and transfer of tabular goods 62, coming from a treatment facility Support frame 64 on a conveyor surface 66 Unloading device 60 are stored. The funding area 66 is in turn with a suction belt 68 Intake openings 69 formed with high accuracy accelerable to a speed V1 is. The speed V1 should be reached before a leading edge 70 of a panel 72 a conveyor moving at speed V1 74 reached. After handing over board 70 to the conveyor 74 becomes the suction belt 68 Standstill brought to take over the following Blackboard. Here, too, are not shown Control interacting position sensors 76 intended.

Claims (5)

1. An apparatus for conveying metal sheets (6), having a conveyor (4) on which the metals sheets (6) are conveyed at a high velocity (V1), a taking out apparatus for taking out a metal sheet (6) from the conveyor (4), means for inspecting the taken out metal sheet (6), and an insertion apparatus (2) for again inserting the taken out metal sheet (6) onto the conveyor (4), the insertion apparatus (2) comprising:

   a) a conveyor plane (8) configured by at least one suction belt (10) provided with suction openings (28);

   b) a drive unit (16) for the suction belt (10);

   c) a vacuum cavity (30) connected to a vacuum installation and communicating with the suction openings (28);

   d) a position sensor (24) for detecting an empty position left on the conveyor (4) by a metal sheet (6) taken out by the taking out apparatus;

   e) velocity sensors (20, 22) for sensing the velocity of the suction belt (10) and of the conveyor (4), resp.;

   f) a control unit (18) which, when an initiating signal from the position sensor (24) appears:

   on the one hand accelerates the suction belt (10) together with a metal sheet (6) lying thereon, from the standstill of a waiting position to the high velocity (V1), such that the metal sheet (6) is inserted into the empty position at the high velocity, and

   on the other hand controls the vacuum within the vacuum cavity (30) such that the suction openings (28) are subjected to a vacuum substantially only during the acceleration of the suction belt (10), such that the metal sheet (6) is accelerated without any movement relative to the suction belt (10).
2. The apparatus of claim 1, characterized in that the suction belt (10) is again decelerated to a standstill after the insertion of the metal sheet (6) onto the conveyor (4).
3. The apparatus of claim 1, characterized in that the suction belt (10) is decelerated to a finite velocity after the insertion of the metal sheet (6) onto the conveyor (4) and is further decelerated to a standstill only after a new metal sheet (6) has been taken over into the waiting position.
4. An apparatus for conveying metal sheets (38), having a conveyor (36) on which the metals sheets (38) are supplied at a first, high velocity (V1), a loading apparatus (34) positioned downstream the conveyor (36) in a conveying direction, for transferring the metal sheets (38) from the conveyor (36) to a drying installation (50), through which the metals sheets (38) run at a second, lower speed, the loading apparatus (34) comprising:

   a) a deposition plane (40) for receiving the metal sheets (38), the deposition plane (40) being configured by at least one suction belt (42) provided with suction openings (43);

   b) a drive unit (46) for the suction belt (42);

   c) a vacuum cavity connected to a vacuum installation and communicating with the suction openings (46);

   d) a position sensor (54) for detecting a metal sheet (38) arriving at the deposition plane (40);

   e) velocity sensors (54) for sensing the velocity of the suction belt (42) and of the conveyor (36), resp.;

   f) a control unit (44) which, when an initiating signal from the position sensor (54) appears:

   on the one hand decelerates the suction belt (42) together with a metal sheet (38) lying thereon, from the high velocity (V1) essentially to a standstill, such that the metal sheet (38), when at standstill, is handed over to a support frame (52) pivoted in an upward direction, and

   on the other hand controls the vacuum within the vacuum cavity such that the suction openings (43) are subjected to a vacuum substantially only during the deceleration of the suction belt (42), such that the metal sheet (38) is decelerated without any movement relative to the suction belt (42).
5. An apparatus for conveying metal sheets (72), having a conveyor (74) on which the metals sheets (72) are conveyed away at a first, high velocity (V1), an unloading apparatus (60) positioned upstream the conveyor (74) in a conveying direction, for transferring the metal sheets (72) from a drying installation, through which the metal sheets (72) run at a second, lower speed, to the conveyor (74), the unloading apparatus (60) comprising:

   a) a deposition plane (66) for receiving the metal sheets (72), the deposition plane (66) being configured by at least one suction belt (68) provided with suction openings (69), the metal sheets (72), when at a standstill, being deposited from above onto the suction belt (68) by means of a support frame (64);

   b) a drive unit for the suction belt (68);

   c) a vacuum cavity connected to a vacuum installation and communicating with the suction openings (68);

   d) a position sensor for detecting a metal sheet (72) arriving at the deposition plane (66);

   e) velocity sensors (76) for sensing the velocity of the suction belt (68) and of the conveyor (37), resp.;

   f) a control unit which, when an initiating signal from the position sensor appears:

   on the one hand accelerates the suction belt (68) together with a metal sheet (72) lying thereon, essentially from a standstill to the first, high velocity (V1), and

   on the other hand controls the vacuum within the vacuum cavity such that the suction openings (69) are subjected to a vacuum substantially only during the acceleration of the suction belt (68), such that the metal sheet (72) is accelerated without any movement relative to the suction belt (68).

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