EP1510489B1 - Method for feeding flat overlapping sheet metal plates - Google Patents

Description

The invention relates to a method for feeding flat, scaled overlapping metal sheets to at least one leading edge stop of a further processing machine, in particular a sheet metal or sheet metal painting machine.

In a known method, the velocity of the entire conveyor belt system is cyclically reduced in order to slow down the objects arranged in a scaled state. The result is that all the scalloped panels slow down at the same time and the foremost panel is placed against the leading edge fence. From there, the board is removed by means of a further transport system defined position. The remaining boards are cyclically accelerated again until the foremost board has reached a certain position, from which the slowdown is again carried out. This system has the disadvantage that very large masses must be accelerated and decelerated, so that the accuracy of the position of the foremost panel in the braking target area due to belt elasticity and other influence influencing parameters scatters. A safe, reproducible leading edge system of the metal sheets is therefore not given.

Furthermore, method guides with retarder elements are known with which a panel delay is caused by friction. The disadvantage here is the low accuracy by hardly reproducible slip processes that can affect in the braking target area during the transfer to the leading edge stop so that too much residual velocity at the stop (damage problem) or too strong a delay (no adequate conditioning of the leading edge of the sheet) , A further disadvantage is that when the conveyor during the braking process, the holding surface is reduced by the drive below the next metal sheet. In the worst case, the holding surface is reduced to zero, so that undefined slip occurs in the last braking phase.

From the US-A-2 257 117 shows a panel handling apparatus with a traction belt to which panels are fed from a first machine, the traction belt being operated at a substantially constant speed corresponding to the speed of the first machine, and a second traction belt separating the panels from the first Traction belt takes over and feeds a second machine, the panels rest flat on the traction belt. A drive drives the second traction belt at variable speed, having a speed which is at least as great as the speed of the first traction belt when the trays are taken over by the first to the second traction belt, wherein initially an acceleration and then deceleration occurs as the panels reach the second machine.

The invention is therefore an object of the invention to provide a method for feeding flat, scaled overlapping metal sheets of the type mentioned, which allows a precise, reproducible conditioning of the respective leading edge of the metal sheets at the leading edge stop. Moreover, a high number of clocks should be feasible.

This object is achieved in that a first, a first conveyor having conveying zone is provided, in which the metal sheets are transported at a first constant speed in a shingled arrangement with continuously developed by vacuum or magnetic effect holding effect of a first holding device and a second the first conveyor zone following conveyor zone having a second conveyor, in which the respective leading plate in the region of its leading edge is taken at a first speed and then slowed to a second speed, wherein the distance (b) between the beginning of the second conveyor and the Leading edge of one of the foremost metal sheet subsequent tracing table at the beginning of the slowing down process of the front sheet metal plate is greater than the path that follows the follower board during the slowing down process of the front sheet metal plate. There is an exact table orientation without any edge damage. The scuppered on the first conveyor objects are thus at a constant speed continuously promoted. So there is a dandruff promotion with constant speed. Alternatively, a cyclically changing speed can also be provided. Cyclically changing speed means: high speed, low speed, high speed, low speed, etc., the speed ratio preferably being in the range of 4: 1 to 2: 1, especially 3: 1. The foremost metal sheet seen in the scale as seen in the direction of transport is decelerated by means of the second conveyor, such that it passes against the leading edge stop at a low residual speed or is transferred at the low residual speed of the device leading it against the leading edge stop. Alternatively, the slowing down by the second conveying means can also take place in such a way that the metal sheet is guided by the second conveying means as far as the leading edge stop and comes to a standstill there. During deceleration of the foremost panel, the scaly arrangement of the remaining panels is constantly advanced by means of the first conveyor. It is alternatively also conceivable that the scale flow of the first conveying means is cyclically promoted. This means to make a cyclic speed change: high speed - low speed, etc. The procedure according to the invention prevents the follower board from running onto the second conveyor during the deceleration process of the predecessor board and thereby being pre-braked in an undefined manner. If the front panel is precisely aligned, it will be in a precisely aligned position by a further processing mechanism accepted. The second conveyor accelerates during the mentioned alignment process back to a speed corresponding to the first conveyor, so that subsequently taken over the now foremost metal sheet of the flake arrangement of the second conveyor and - accordingly slows down as described above and exactly aligned at the leading edge stop. Preferably, the respective foremost panel rests on the second conveying means, wherein during the slowing down process no relative movement takes place between the second conveying means and the metal sheet and therefore an exact reproducibility is present. During deceleration, there is no sliding movement between the second conveyor and plate in the main phase. The sheet metal is exactly slowed down with the second conveyor (belt drum) according to a fixed, during each clock same place - machine angle motion law. The below-defined, preferably provided holding effect by vacuum is dimensioned so that the curve of the deceleration is independent of the weight of the panel and the surface finish of the metal sheet. The movement of the second conveyor and plate is synchronous in the deceleration phase, without relative movement. Only shortly before the arrival at the front edge stop, especially at the front marks, this adhesion (by switching off the vacuum) is released, so that the second funding then pushes the metal sheet, but only with a very small force resulting from the now present Friction without vacuum between strand and metal sheet results. The scaling is made such that During the deceleration process of the foremost panel, the overlap zone with the follower panel increases. By appropriate speed tuning of the two conveying means, taking into account the formats of the objects to be supplied in each case, a high number of processing per unit time can be realized. The objects rest on the first and the second conveying means, that is, the objects are located above the conveying means; Therefore, there is no overhead transport, in which the objects are held on the underside of the conveyor. This is of importance because, among other things, the scaling of the objects is designed in such a way that the front panel is underlaid by the subsequent one, etc., so that the panels are only accessible from below in each case only in the non-overlapped area. As mentioned, there is thus a slowdown to a relatively low speed. If the object has assumed this low speed, it slides a short distance over the base and thus passes against the leading edge stop and is aligned there. Alternatively, it is also possible that after the slowing down the object is taken over by a further device, which detects the object (by gripper device, suction device and / or magnetic device) and defines it up to the leading edge stop, so that the orientation takes place there. Alternatively, it is also possible for the second conveying means to decelerate the object to a standstill, wherein the deceleration is realized in such a way that at standstill or shortly before the standstill is reached, the object occurs against the leading edge stop and is thereby aligned. Preferably, the distance (c) from the front edge of the foremost metal sheet at the beginning of deceleration to the end of the first holder is greater than the dandruff length, which is the dimension between the leading edge of a metal sheet and the leading edge of a immediately following metal sheet.

Preferably, the respective foremost metal sheet is guided at the second speed against at least one leading edge stop or approaches at this speed the leading edge stop, wherein the front metal sheet is held during its deceleration in a stationary holding zone of a second holding means of the second conveying zone by switchable negative pressure and off this holding action is, as soon as the leading edge of the foremost metal sheet with only a small distance to the leading edge stop, whereby after conditioning and thereby aligning the leading sheet metal plate at the leading edge stop a removal to the processing machine, and wherein the distance (d) between the leading edge stop and the Leading edge of the follower plate immediately following the foremost metal sheet at the time of switching on the holding action of the second holding device is smaller than the distance (e) from the leading edge stop until to the end of the second holding device.

It is provided that a first holding device is assigned to the first conveying means. Preferably, the second conveyor a second holding device be assigned. The first and / or the second holding device may preferably be designed as a suction device and / or as a magnetic device. The suction device is designed such that the objects, in particular the metal sheets, are held on the surface of the conveying means by suction, so that a relative movement between the corresponding conveyor and the objects is reliably avoided. In particular, due to this holding action, the braking operation can be carried out without slippage of the metal sheet on the conveyor, so that a high precision is achieved at high cycle speed. If the objects are ferromagnetic components, for example steel sheet panels, a magnetic device which is located below the conveyor and thus prevents a relative displacement between the metal sheet and the conveyor can also be used as the holding device. The metal sheets thus move exactly at the speed that is predetermined by the corresponding funding.

In particular, it can be provided that an endlessly circulating conveying means is used as the first conveying means. The first and second conveying means are therefore strands, which preferably consist of a plurality of parallel juxtaposed belts on which the metal plates rest,
wherein below the upper strand, the holding device is arranged, which fixes the metal sheet or the metal sheets on the belt / fix.

Furthermore, it is advantageous if the holding by means of the second holding device -as seen in the transport direction-takes place only over a section of the second conveying means. For a position fixation, this section is sufficient and keeps the fixation zone relatively small, so that only correspondingly small amounts of energy are required for the holding effect.

Furthermore, it is advantageous if the second holding device is located substantially on the upstream half of the second conveying means.

It is particularly preferred if the holding action of the second holding device is switched on and off. In the case of a vacuum suction device, the vacuum source can be switched on and off or there is a pneumatically acting switching valve in the system, with the suction on and off. The suction is activated as soon as the foremost metal sheet is taken over by the second conveyor; it is deactivated or greatly reduced just before the leading edge of the braked metal sheet hits the front edge stop. If a magnetic device for unfolding the holding effect is present, a solenoid device is preferably used, so that the holding force can be activated or deactivated by electrically switching on or off.

The holding action of the first holding device preferably acts continuously, that is, it will not connected. Exception: at the last panel of the scale flow is switched.

In particular, it can be provided that the first and / or the second holding device is formed by at least one suction box located below the first and / or second conveying means. The suction box is preferably connected via a switching valve to a vacuum source. In order to let the suction effect through the first and / or the second conveying means to act on the panels, the first and / or the second conveying means is formed permeable to air.

The second speed is much smaller than the first speed; it preferably has a very low value or it is operated in such a way that the panel is braked to zero speed and that on reaching standstill the leading edge of the panel comes against the leading edge stop.

It can preferably be provided that at a nominal speed corresponding to approximately 9,000 to 10,000 panels per hour, the first speed is approximately 1 m / s. The second speed may, for example, have a value of about 0.2 or 0.1 m / s. In particular, it can be provided that the second speed is designed to be 0.25 to 0.1 times the first speed.

Figur 1

eine Seitenansicht auf eine Vorrichtung zum Zuführen einer Blechtafel gegen einen Vorderkantenanschlag,

Figur 2

eine schematische Seitenansicht der Vorrichtung gemäß Figur 1,

Figur 3

eine schematische Seitenansicht der Vorrichtung der Figur 1,

Figur 4

eine schematische Seitenansicht der Vorrichtung der Figur 1 und

Figur 5

eine schematische Seitenansicht der Vorrichtung der Figur 1.

The drawing illustrates the invention with reference to an embodiment. Show it:

FIG. 1

a side view of an apparatus for feeding a metal sheet against a leading edge stop,

FIG. 2

a schematic side view of the device according to FIG. 1 .

FIG. 3

a schematic side view of the device of FIG. 1 .

FIG. 4

a schematic side view of the device of FIG. 1 and

FIG. 5

a schematic side view of the device of FIG. 1 ,

The FIG. 1 shows a device 1 for feeding flat objects 2 against at least one leading edge stop 3. The objects 2 are formed as metal sheets 4.

The device 1 has a first conveying means 5 and a second conveying means 6. The first conveyor 5 is formed by a circumferential strand 7 and the second conveyor 6 by a circumferential strand 8. The circumferential strand 7 has an upper run 9 and a lower run 10 and is guided at one end to a guide wheel 11. The lying at the other end pulley of the strand 7 is not shown on the figure for reasons of space. The circumferential strand 8 has at its end a respective deflecting wheel 12 or 13. Its upper run 14 lies in the plane of the upper run 9 and its lower run 15 is guided over a tensioning roller 16. Preferably, the circumferential strands 7 and 8 each consist of a plurality of spaced-apart belts, so that a distributed over the width of the metal sheets arranged support is formed. The belt are associated with corresponding guide wheels 11 to 13 and tension rollers 16.

The belts of the strands 7 and 8 are made permeable to air. Below the upper run 9 there is a suction box 17 indicated in the figure, which is connected to a vacuum source. Further, located below the upper run 14, a suction box 18, which is also connected via a switching valve 19 to or to another vacuum source. The strands 7 and 8 thus form Saugtrums on which the objects are held immovably by negative pressure. The strand 7 runs by means of a not shown, preferably electric drive with a constant, first speed v ₁ to. The transport direction is indicated by means of the arrow 20 with respect to a transport plane 21. A speed or controllable electric or mechanical drive drives the strand 8 in such a way that it is also correspondingly accelerated and decelerated in the transport direction (arrow 20). It has the instantaneous velocity v ₂ .

From the FIG. 1 It can be seen that the metal sheets 4 are in a shingled arrangement to each other, that is, the frontmost lying sheet 4 'overlaps the Wicklungsplatte 4'', wherein the leading edge portion of the metal sheet 4 "below the trailing edge portion of the metal sheet 4' Follow-up panel 4 '' upstream Metal sheets are scaled accordingly (not shown).

The suction box 17 forms a first holding device 22, which fixes the metal sheets 4 in a shingled arrangement on the upper strand 9 by means of negative pressure. The holding action of the first holding device 22 is constant. The suction box 18 forms a second holding device 23 for the respective frontmost sheet metal plate 4 ', wherein the holding effect by means of the switching valve 19 on and off or can be amplified and reduced, that is, the vacuum source is connected to the suction box 18 or there is a Separation of the connection.

As can be seen from the figure, the suction box 18 is arranged in the region of the upstream side of the circumferential run 8 with respect to the transport direction (arrow 20). In this respect, the second holding device 23 extends only over a portion 24 of the entire length of the upper strand 14th

In the following, the metal sheets are generally designated by the reference numeral 4, the sheet metal plate lying at the front carries the reference numeral 4 'and the following table the reference numeral 4 ".

This results in the following function: The metal sheets 4 are supplied in a shingled arrangement by means of the run 7. They rest on the upper side of the upper run 9 and are fixed by the effect of the negative pressure of the suction box 17. The suction in the suction box 17 is constant; the speed v ₁ is also constant. Reaches the vorstest lying metal sheet 4 'with its leading edge portion of the strand 8, the latter takes over a corresponding, continuously enlarging portion of the metal sheet 4'. This is done with respect to the run 8 at the speed v ₁ , that is, the runs 7 and 8 have the same speed v ₁ at this point in time (v ₁ = v ₂ ). In the course of the process, the negative pressure acting on the corresponding metal sheet 4 is "switched off" by overlap by the follower board 4. By appropriate position of the switching valve 19 it is ensured that a negative pressure is built up in the suction box 18 so that a region of the metal sheet 4 'is established. sucked firmly onto the top of the upper run 14 and the metal plate 4 'is thus maintained in immovable position to the upper run 14. the structure of the negative pressure takes place only upon complete covering of the suction box 18 through the metal plate 4'. There is then a reduction in the speed v ₂ of the During the deceleration process, the metal sheet 4 'is held firmly on the upper strand 14 by the negative pressure so that no relative movement can occur between the strand 8 and the metal sheet 4'. that the metal sheet 4 'has only a very small speed in it The vacuum of the suction box 18 is now switched off, so that the metal sheet 4 'is released and slips over the base 27, so far until the front edge 25 against the leading edge stop. 3 occurs. The underlay 27 extends between the downstream end of the run 8 and the leading edge stop 3. In this way, the plate 4 'is aligned precisely. During the deceleration process of the run 8, the run 7 continues to run at the speed v ₁ , so that the follower table 4 "is pushed a corresponding distance further under the plate 4 '. If the foremost metal sheet 4 'is aligned exactly at the leading edge stop 3, then it is gripped at its front edge 25 and fed into the transport direction (arrow 20) for further processing. Before reaching the leading edge stop 3, the negative pressure in the suction box 18 is turned off by means of actuation of the switching valve 19. If the metal sheet 4 'leaves the leading edge stop 3, the strand 6 is accelerated to the initial speed, ie the speed v ₁ , so that the front metal sheet 4 can now be taken over by the strand 6 in its leading edge region, as already described above Sheet metal 4 'has been explained. It is then again the holding device 23 is activated. The above-explained processes are repeated continuously, so that the metal sheets 4 are processed at high clock rate and thereby aligned.

The FIGS. 2 to 5 show the device of Figure 1 in a schematic form, wherein the following terms, such as "beginning" and "end", as seen in the transport direction of the metal sheets 4 are defined, ie in the direction of arrow 20 of FIG. 1 , Accordingly, according to FIG. 2 the distance a between the end of the second holding device 23rd and the end of the first fixture 22 is supplemented by a margin of security, which the sheets pass through in time, which is required for a complete vacuum build-up, smaller than the scale length between the sheets. Under scale length of the scaled arranged sheet metal plates 4 is the measure between the front edge of a metal sheet 4 and the front edge of the immediately following metal sheet 4 to understand. Due to the aforementioned distance a is a secure acquisition of the metal sheets 4 from Trum 7 on the strand 8 possible.

According to FIG. 3 For example, the distance b between the beginning of the second conveyor and the leading edge of a follower table 4 "at the beginning of the deceleration process of the predecessor panel 4 'is greater than the distance the follower panel 4" travels during the deceleration process of the predecessor panel 4 " , the follower board 4 "runs on the second conveying means 6 during the deceleration process of the predecessor board 4 'and is braked indefinitely.

From the FIG. 4 It can be seen that the distance c from the front edge of the predecessor board 4 'at the slowing down start to the end of the first holding device 22 is greater than the flake length. If this were not the case, the metal sheet 4 to be braked is simultaneously driven by the first conveying means 5 (the successor board 4 "must be underlaid by the conveyor 5 at the start of deceleration of the preceding board 4 ', that is, cover the suction box 17).

According to FIG. 5 it is provided that the distance between the leading edge stop 3 and the leading edge of the follower board 4 '' (dimension d) at the time of switching on the vacuum (vacuum in the suction box 18) is smaller than the distance from the leading edge stop 3 to the end of the second holding device 23rd (Dimensions). If this were not the case, then the vacuum would capture the metal sheet 4, which is to be aligned. The predecessor sheet 4 'to be aligned must be underfoot when the vacuum is switched on (for the following table 4'').

In the FIG. 5 As an alternative embodiment, reference is made, with reference to reference numeral 28, to a device which takes over a slowed-down metal sheet 4 'after the vacuum of the suction box 18 has been switched off. The acquisition takes place at the delayed, very low speed v ₂ . The device 28, which is indicated only schematically, guides the metal sheet 4 'with further delay up to the front edge stop 3, so that there is a controlled, reproducible alignment.

The invention thus preferably relates to a slowing of the metal sheets in the phase of feeding the respective leading edge to an alignment stop by means of circulating vacuum suction belts, wherein the respective delayed sheet metal sheet is detected non-positively. The deceleration is preferably at a speed v ₂ which is approximately 10% of the speed v1 or close to zero. There is a delay and re-acceleration the vacuum belt, wherein the acceleration is performed on the Tafelzuführgeschwindigkeit from the upstream Trum and this speed is kept constant for the adoption of the panel. The deceleration is then made to a defined speed to gently drive the panel against the leading edge stop. By switching on and off the vacuum (switching on before board acceptance and during the subsequent deceleration, switching off the vacuum before reaching the leading edge stop or before re-accelerating the suction belt to sheet feeding speed to take over the next board), it is ensured that no uncontrolled shifting of the boards takes place , The aligned at the leading edge stop panel is preferably transferred to a system not shown and not described, in order to process the metal sheets in a defined position can. By the invention, a high braking accuracy or positioning accuracy is achieved by driving a speed-way profile in the same way for each panel in the machine cycle. There is a scratch-free introduction of force into the panels due to the negative pressure or a magnetic position.

The metal sheets 4, 4 'are each slowed down completely flat. The surface of the deceleration device (second conveyor 6) is located in the tray level. When the vacuum is switched off at the end of the deceleration process, there is no movement transverse to the table running level, in particular perpendicular to the table running level, which is the exact one Installation of the metal sheets 4 'to the leading edge stop 3 could be harmful.

Compared with known reciprocating oscillating units with vacuum head principle of the invention, the circulating endless belt drive opens up the advantage that no backward stroke is present, that is much more time is available for smooth, jerk and sliding friction free deceleration is available or it can be the interpretation of Feeding speed can be selected lower overall, which benefits the safe operation of the system as a whole. Furthermore, a circumferential Riementrum is advantageous in terms of a possible scratching of the underside of the metal sheets. During deceleration, which requires a large holding vacuum, there is no relative movement between the plate 4 'and the belt (second conveyor 6), so that scratching is precluded. In the phase of applying the metal sheet 4 'with a residual speed at the front edge stopper 3 preferably consisting of several front stops, the belts (second conveying means 6) slip under the metal sheet 4' without holding action (vacuum or magnetic force is switched off). Furthermore, since the relative speed is very low, no scratches occur due to the belt system mentioned. Worn belt surfaces can be easily removed by simple and cost-effective belt replacement. With regard to the entire panel arrangement, according to the invention, only one metal sheet, namely the foremost metal sheet 4 ', is slowed down from the entire shingled stream. The rest of the shingled stream keeps moving. This is of particular interest because the scale flow is formed in such a way that the panel lying at the front rests on the following table. That is, it is carried out according to the invention, the slowing down from below, because the bottom of the metal sheets rests on the conveyor 5 and 6 respectively. This solution is chosen, although for holding the corresponding metal sheet 4 'by means of vacuum or magnetic force only the area of the panel is accessible from below, which is not in overlapping position to the next table.

Claims (11)

1. A method for feeding flat sheet metal boards (4), which overlap one another in a scaled manner, to at least one leading edge stop (3) of a processing machine, in particular a metal sheet printing or metal sheet varnishing machine, comprising a first conveying zone, which encompasses a first conveying means (5), in which zone the sheet metal boards (4) are transported at a first constant speed in scaled configuration with a holding effect, which is continuously developed by means of low pressure or magnetic effect, of a first holding device and comprising a second conveying zone, which follows the first conveying zone and which encompasses a second conveying means (6), the respectively foremost sheet metal board (4') being taken over in said second conveying zone in the area of the leading edge (25) thereof at a first speed and then being slowed down to a second speed, characterized in that the distance (b) between the beginning of the second conveying means (6) and the leading edge of a successive sheet metal board (4"), which follows the foremost sheet metal board (4') at the onset of the slowing-down process of the foremost sheet metal board (4') is greater than the distance, which the successive sheet metal plate (4") covers during the slowing-down process of the foremost sheet metal board (4').
2. The method according to claim 1, characterized in that the distance (c) from the leading edge of the foremost sheet metal board (4') at the onset of the slowing-down to the end of the first holding device (22) is greater than the scale length, which is the measure between the leading edge of a sheet metal board (4) and the leading edge of a directly following sheet metal board (4).
3. The method according to any one of the preceding claims, characterized in that the respectively foremost sheet metal board (4') is guided against at least one leading edge stop (3) at the second speed or approaches the leading edge stop (3) at this speed, wherein the foremost sheet metal board (4') is held during its slowing-down in a stationary holding zone of a second holding device (23) of the second conveying zone by means of a shiftable low pressure and that this holding effect is turned off as soon as the leading edge (25) of the foremost sheet metal board (4') is located at only a small distance to the leading edge stop (3), wherein a transport to the processing machine is carried out after abutment of the foremost sheet metal board (4') to the leading edge stop (3) and thereby aligning the sheet metal board (4'), and wherein the distance (d) between the leading edge stop (3) and the leading edge of the successive sheet metal board (4"), which directly follows the foremost sheet metal board (4') at the turn-on moment of the holding effect of the second holding device (23), is smaller than the distance (e) from the leading edge stop (3) to the end of the second holding device (23).
4. The method according to any one of the preceding claims, characterized in that the second speed is almost zero or equals zero.
5. The method according to any one of the preceding claims, characterized in that the sheet metal boards (4) are held in an area of the second conveying zone.
6. The method according to claim 5, characterized in that the holding is carried out in the area of the second conveying zone by means of low pressure or magnetic effect.
7. The method according to any one of the preceding claims, characterized in that an endlessly rotating conveying means is used as first conveying means.
8. The method according to any one of the preceding claims 5 to 7, characterized in that the holding - viewed in transport direction - is carried out only via a part (24) of the second conveying zone.
9. The method according to any one of the preceding claims 5 to 8, characterized in that the holding in the second conveying zone is substantially carried out in the upstream half of the second conveying zone.
10. The method according to any one of the preceding claims 5 to 9, characterized in that the holding effect in the area of the second conveying zone can be turned on and off.
11. The method according to any one of the preceding claims, characterized in that conveying means, which are embodied so as to be pervious to air, for developing a low pressure effect on the sheet metal boards are used as first and/or second conveying means (5, 6).

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