EP3490740A1

EP3490740A1 - System for automatically setting down metal sheets onto a set-down stack for producing transformer cores

Info

Publication number: EP3490740A1
Application number: EP16754209.1A
Authority: EP
Inventors: Alex Fritz Rudnicki
Original assignee: Guedel Group AG
Current assignee: Guedel AG
Priority date: 2016-07-29
Filing date: 2016-07-29
Publication date: 2019-06-05
Also published as: WO2018019387A1

Abstract

A system for automatically setting down metal sheets onto a set-down stack for producing transformer cores comprises a transporting device for the positionally exact transporting of individual metal sheets stacked in a directed manner on a pick-up stack onto the set-down stack. The transporting device comprises a gripper (20) for gripping an uppermost metal sheet (3) on the pick-up stack, for holding the metal sheet (3) during transport and for setting down the metal sheet (3) onto the set-down stack. Arranged on the gripper (20) are elements (60.1, 60.2) for maintaining a positioning of stacked metal sheets on the pick-up stack and/or on the set-down stack.

Description

Plant for automatically depositing sheets on a tray for the production of transformer cores

Technical area

The invention relates to a system for automatically depositing sheets on a discard pile for the production of transformer cores, comprising a transport device to m positionally accurate transporting individual stacked stacked on a receiving stack sheets on the Ablagesta pel, wherein the transport device a gripper for gripping a top sheet on the receiving stack, for holding the sheet during transport and for depositing the sheet on the discard pile comprises. The invention further relates to a method for automatically depositing sheets on a discard pile for the production of transformer cores, wherein the sheets are removed individually from a Aufna hmesta pel directed stacked sheets, accurately transported and stored on the discard pile. State of the art

Large transformer cores with typical dimensions of z. B. about 5x 10 m and a weight of up to 350 t consist of several stacks of thin sheets. For example, a core can consist of a total of up to 60Ό00 sheets, each with a thickness of 0.3 mm (including insulating coating). It is composed of several stacks of sheets, each of the Sta pel z. B. 5Ό00-6Ό00 a ufeinander stacked sheets and thus a height of z. B. 1 '600 mm achieved.

Manual stacking is often done on a 90 ° tilting table, so that after laying the coil can be inserted or more coils can be introduced. The sheets used often include positioning holes, which serve on the one hand for centering and accurate alignment of superimposed sheets, on the other hand also for the contraction of sheets of a (partial) stack.

The manual stacking is complicated and requires a high personnel deployment. There are efforts to automate the batch process. Thus, the KR 2014 003 1 735 A (Hyundai) shows a device for stacking transformer sheets, wherein the sheets are stacked by means of upwardly projecting centering pins. At one arranged on a articulated robot gripper Ka meras are provided to check the correct positioning of the sheet to be deposited before depositing. DE 103 32 01 8 B3 (Heinrich Georg GmbH) relates to a device for holding stacked sheets, in particular transformer sheets, which each have at least one thread hole and are stacked on pallets; above the sheets at least one threading bolt is provided, which is movable in the thread hole of the sheet and then with this in the direction of the pallet. In order to prevent the topmost sheet from "floating away" from its position due to an air cushion after the removal of the threading pin, a guide cartridge is inserted into a through opening in the pallet before it starts to be unstacked. This is contacted by the threading pin during stacking and down as needed pushed or pulled up to the top of the last stacked sheet metal. Thus, the guide cartridge keeps the top sheet and a portion of already stacked sheets over a longer period of time in common. The Fädelbolzen is coaxially surrounded by a hold-down, the hold-down is also provided a Abst mature on which the guide cartridge abuts, whereby it is decoupled from the threading bolt.

This prevents a loss of correct positioning on the discard pile. However, the method is relatively expensive, and the use of separate guide cartridge complicates the adaptation to different applications and core geometries. The CH 666 977 A5 (MWB) relates to a Blechhubeinrichtung for safe and reproducible lifting of individual sheets of a stack of sheets. The device has suction grippers with a compressed air-controlled cylinder and a vacuum cleaner and a striking element. The impact element uses 5 to 10 strokes per second a us, in order to achieve a separation of the sheets adhering below from the uppermost sheet. The grippers can be operated differently, so that the sheet is deformed; There may also be several impact elements.

By the proposed method, adhering sheets can be separated. However, the correct positioning of the initially adhering and subsequently separated sheets on the receiving stack is usually lost. Thus, a correction of the positioning is necessary during subsequent transport of the sheets. This reduces the efficiency of an automatic transport process.

Presentation of the invention

The object of the invention is to provide a plant belonging to the technical field mentioned above and a corresponding method, which allow an efficient and flexible positionally accurate transport of the transformer sheets. The solution of the problem is defined by the features of claims 1 and 24. According to the invention, elements are arranged on the gripper for maintaining a positioning of stacked sheets on the receiving stack and / or on the stacking pel. Accordingly, when removing and / or depositing on the receiving or discard pile under the removed or discarded sheet metal sheets are temporarily fixed to maintain their positioning.

The temporäre re fixation prevents loss of correct positioning of not yet recorded or already sta pelted transformer plates. Because the element is arranged on the gripper and the sheets are only temporarily fixed, a high flexibility results.

The gripper grips the sheets especially exclusively on their upper main surface.

Since the sheets on the recording stack exact position, d. H. precisely aligned, provided, the positioning while picking up, from the transport device positionally accurate, d. H. while maintaining their relative position, and the positioning while depositing again maintained, is in the context of sheet transport usually neither a readjustment nor a specific detection of the sheet metal position relative to the gripper necessary. This results in a fast transport process and thus a short production time of the transformer core. Advantageously, the elements comprise at least one positioning pin for cooperating with a positioning hole in the sheets to be deposited. Such positioning holes are common in transformer sheets. They are also used in the manual laying of transformer cores, namely in the area of the storage pile, to ensure that the stacked sheets are aligned by means of stationary, rising pins or by means of pin-type tools. The positioning holes are often also used to contract the sheets of a (partial) stack.

Now, if elements are arranged on the gripper, which can interact with the existing positioning holes in the sheets, namely one or several positioning pins, results in a simple way a reliable and precise mechanical positioning of the sheets.

When placing the sheet on the discard pile, the positioning pin or the positioning pins can be temporarily moved into positioning holes in the sheet to be deposited and in sheets on the discard pile. This fixed on the one hand, the relative position of the sheet to be deposited with respect to the already existing sub-stack, on the other hand, the already deposited on the stack of parts sheets are prevented from slipping - for example, due to the action of the sheet to be deposited. The positioning pin is preferably moved before the contact of the sheet to be deposited with the uppermost sheet in the positioning holes. But this can also be done only after dropping, but before loosening the gripper.

Advantageously, the positioning pin on a shaft and a movably mounted in the shaft inner pin. The outer cross section of the shaft is particularly adapted to the geometry of the positioning holes, and the shaft is used in particular for accurate centering of successive sheets. As will be discussed below, the inner pin projecting distally from the shaft may serve as a probe for detecting misplacements and / or as a guide pin for the sheets pierced by it.

The movable mounting of the inner pin allows a retraction of the inner pin (or a portion thereof) in the shaft, especially when an axial mechanical force is applied to it.

Advantageously, the inner pin is biased by spring means in a position extended relative to the shaft. If the axial force falls away, the inner pin is automatically extended again. Preferably, the spring means (eg in the form of a helical spring) are designed so that even at low forces takes place a return, because the sheets used for the construction of the transformer core have a very thin insulation layer, the damage is absolutely to avoid so does not affect the electromagnetic properties of the transformer core. at a low reversing force, however, damage to the sheets are avoided when hitting the inner pin.

The retraction of the inner pin is not only when hitting a sheet metal top - z. As if a sheet is positioned inaccurately important, but also in the first phase of the construction of the storage pile or when transporting the last sheets from the receiving stack. In these cases, the inner pin penetrating the positioning holes comes into contact with the underlying support surface. The (partial) retraction into the shaft then enables a contacting of the sheets in the shank region of the positioning pin and thus the exact centering of these sheets. Advantageously, the shaft and the inner pin each have a circular cross-section. An outer diameter of the shaft is then at least three times, preferably at least five times, an outer diameter of the inner pin. In addition to areas with a circular cross section (ie circular cylindrical areas), the shaft and the inner pin can also have areas with a reduced cross section. In particular, the shaft can have a conical region in a distal region (ie at the transition to the inner pin). This serves to gradually center slightly shifted sheets when the shaft is moved in the distal direction to the stack of sheets. A distal end of the inner pin may be rounded to prevent damage to the sheets when hitting the inner pin. Common positioning holes in transformer sheets are circular and have an inside diameter of 10 - 32 mm. The inner pin thus has, for example, a diameter of 2-4 mm, while the outer diameter of the shaft is adapted to the inner diameter of the holes, so in particular corresponds to a tolerance of this inner diameter. The cross sections of the shaft and the inner pin need not be circular, and polygonal or other shapes are also conceivable, in particular shapes which can cooperate with circular positioning holes. The ratio between the outer diameter of the shaft and the outer diameter of the inner pin may also differ from the stated values. Advantageously, a sensor for detecting a repelling of the inner pin relative to the shaft is arranged on the positioning pin. Thus, an abutment of the inner pin movably mounted in the positioning pin can be detected in order to detect a faulty stacking of a stack. As a result, the necessary actions for correcting the stack alignment can be initiated.

Advantageously, the gripper has at least two positioning pins, which are arranged on a movable element along a longitudinal extent of the gripper. The use of at least two locating pins ensures that not only a position at the corresponding locating hole but also the orientation of the detected sheet is correct. The mobility allows an adaptation to the sheet metal geometry, because with conventional transformer cores, the size of stacked sheets varies, so that an adaptation is necessary in the context of the construction of a core.

Preferably, a laser source is arranged on the movable element, which generates a light spot on a plate arranged parallel to the holding plane, wherein the light spot is generated such that it is aligned with a positioning hole of the sheet when correct positioning of the corresponding positioning pin is achieved. This simplifies the correct initial positioning of the gripper, which is done in particular manually. Advantageously, the gripper comprises a plurality of suction pads for detecting and holding the sheet. These are easy to control and allow gripping and depositing without damaging the sheet metal surface.

Preferably, at least one of the plurality of suction grippers can be moved perpendicular to a holding plane of the gripper with a first stroke into a standby position behind the holding plane. As a result, suction grippers can be withdrawn in areas which lie outside the area of the currently detected sheet metal. A collision with surrounding elements, especially with the storage stack surrounding mounting elements for the sheets to be deposited, can be avoided. The first stroke is for example about 200 mm. Advantageously, at least one of the plurality of suction grippers is movable back and forth perpendicular to a holding plane of the gripper with a second stroke, so that a shaking movement of the detected sheet results. The second stroke is for example about 30 mm. The shaking motion can be performed at a desired frequency. It is advantageously about 2 - 20 Hz.

Advantageously, the gripper has a sheet thickness gauge with a sensor for detecting a number adhering to the gripper sheets. The sensor may be, for example, an inductive sensor.

Thus, it can be determined after removal of the sheet, whether adhering to the detected sheet more sheets. If this is the case, the detected sheet (and thus the adhering plates below it) is shaken by the gripping device. With the help of the sensor can also be determined whether the other sheets have now solved and the transport process of the sheet can be continued to the discard pile.

When shaking, a positioning pin advantageously penetrates positioning holes in the detected sheet metal, in the sheets to be shaken off and in sheets on the receiving stack. This ensures, on the one hand, that the shaken-off sheets are returned to the pick-up stack with a correct position. On the other hand, it ensures that the top sheets of the receiving stack maintain their position.

In a first embodiment, the at least one of the plurality of suction pads, which is used for shaking off, arranged on a lifting cylinder, wherein the lifting cylinder has an upper stop and the suction pad is moved back and forth so that he on reaching the second Hu bs on Stop strikes, resulting in a shock. The impact promotes shaking and increases the likelihood of rapid separation of the adhering sheets from the sheet caught by the pads.

In a second embodiment, the Auffahren on a stop eliminates and the shaking off takes place only due to the changing accelerations of the shaken-off sheet metal or the plates to be shaken off. Preferably, an actuation of a plurality of reciprocable suction pads is independent of each other steuerba r. This can be different

Create impact pattern on the adhering sheets. This also increases the likelihood of a quick disconnect. Advantageously, at least one of the suction pads on the gripper is displaceable in the holding plane. This creates greater flexibility in adapting to different sheet metal geometries.

The gripper may further comprise a camera for optically detecting the stack. With the help of the recorded video images, the automatic positioning of the gripper can be supported, especially in cases where the transformer sheets have no positioning holes.

Preferably, the gripper comprises a lowerable holding-down device, which is absent when depositing the metal sheet on the storage stack on an adjacent stack, in order to secure a position of metal sheets on this adjacent stack. In a preferred embodiment of the system according to the invention, the elements for maintaining a positioning of staked sheets comprise at least one device for producing a glue point on a metal sheet located in a holding position with respect to the gripper. When placing the sheet on the discard pile thus a glue dot is generated on an upper surface of the deposited sheet. With a holding position is meant a relative position of the sheet to the gripper, in which the sheet is held by the gripper, can be taken or has been released. In particular, the sheet is in the holding plane of the gripper or at a small distance parallel thereto. The generation of the adhesive point can take place simultaneously with the deposition, that is, upon contact of the deposited sheet with the uppermost sheet of the storage pile, shortly before or shortly thereafter, prior to retraction of the gripper.

In the area of the generated adhesive point or the adhesive dots produced, the subsequent sheet is fixed when it is deposited on the now deposited sheet. This fixation takes place, for example, alone due to the weight of the subsequent sheet, but can be supported when the gripper exerts a certain pressure on the deposited sheet metal when depositing.

The fixation prevents slippage of the top sheet or the top sheets, especially due to effects of the subsequently deposited sheet. The danger of such slippage is in particular due to air trapped between the uppermost sheet metal and a subsequent sheet, thus forming a kind of "air cushion." The use of adhesive dots is particularly advantageous if no positioning holes can be used.

Advantageously, the device for generating the adhesive point is designed as an adhesive applicator. As a result, a gluing point with a defined amount of material can be produced in a simple manner. The applicator may be implemented in the manner of a stamp. Alternatively, spray nozzles or pipette-like application devices can also be used. The punch is preferably movable in a direction perpendicular to the holding plane in order to be able to interact selectively with the metal sheet. The device also preferably comprises a feeding and metering device for the material to be applied.

As a material for the adhesive point, an adhesive can be selected in the narrower sense. However, it has been shown that, for example, certain lubricants, such as vaseline, can be used as long as they reliably prevent only the top sheet from sliding away. A lasting effect is not necessary because after placing one or a few more sheets, the risk of slipping anyway banned. It must be ensured that the substance used does not show adverse interactions with transformer oil.

The amount of material is to be chosen so that a thin layer results in a thickness of, for example, not more than 2 μηι, preferably not more than 1 μΐτι, thus preventing that due to the adhesive dots results in an undesirable increase in thickness of the sheet stack.

Preferably, the transport device comprises a portal, in particular a surface portal, on which the gripper is movably mounted, wherein the portal detects a work area, which the receiving stack and a building area for building the Transformer core includes. The grippers mounted on the portal can thus reach all positions which are necessary for the gripping and placing of metal sheets in the automatic construction of the transformer core.

Advantageously, the gripper is mounted vertically movable on the portal. The gripper can thus be lowered as a whole to the respective recording or discard pile and raised for transport.

Advantageously, the transport device comprises at least two grippers, wherein a first of the at least two grippers for gripping yoke plates and a second of the at least two grippers for gripping leg plates is dimensioned. Particularly preferably, the transport device comprises a yoke and two leg grippers.

If a portal is used, preferably several bridges are arranged on the portal, each of the bridges carrying one of the grippers.

Preferably, the plant comprises an alignment table for positioning of sheets, wherein the gripper can place sheets on the alignment table and record from the alignment table. If a portal is used, the alignment table is also advantageously located in the working area of the portal.

Advantageously, the sheet is deposited only with detected mis-stacking on the alignment table, positioned on the alignment table and resumed. Otherwise, a position-accurate transport takes place in which the alignment table does not have to be used. This eliminates the need to store and retrieve the sheet, and the overall transport time can be significantly reduced.

From the following detailed description and the totality of the claims, further advantageous embodiments and feature combinations of the invention result. Brief description of the drawings

The drawings used to explain the embodiment show: Fig. 1 is a schematic representation of a system according to the invention for the automatic placement of sheets on a discard pile for the production of transformer cores;

Fig. 2A is a schematic oblique view of a gripper for gripping a

sheet;

Fig. 2B shows a detail of Figure 2A, which the suction pads and the

Positioning pins shows;

Fig. 2C is a schematic side view of two suction pads and a

Positioning pin; Fig. 3A, B is a cross section and a side view of the positioning pin;

4A is a schematic oblique view of the gripper when shaking off adhering sheets.

4B shows a section from FIG. 4A, which shows the suction grippers and the

Positioning pins shows; 4C is a schematic side view of two suction pads and a

Positioning pin when shaking off;

Fig. 5A, B is a schematic oblique view and side view of the suction pads and a positioning pin in centering a top portion of a stack of sheets; FIG. 6A is a schematic oblique view of the detection of misplaced sheets; FIG.

FIG. 6B shows a section from FIG. 6A; and

Fig. 7 is a schematic oblique view of the generation of a glue point.

Basically, the same parts are provided with the same reference numerals in the figures. 1 shows a schematic representation of a system according to the invention for automatically depositing sheets on a stack of stacks for the production of Transformer cores. The system 1 comprises a surface portal 10 with two support rails and three connecting them parallel bridges 1 1, 1 2, 1 3. At each bridge 1 1, 1 2, 1 3 is a gripper 20, 30, 40 in a conventional manner on a along the bridge 1 1, 1 2, 1 3 verfahrba ren carriage along a vertical axis arranged movable. The bridges 1 1, 1 2, 1 3 are along the support rails linea r movable, so that in total for each gripper 20, 30, 40 x, y, z degrees of freedom.

The surface gantry 10 with the grippers 20, 30, 40 arranged thereon detects a working area 14. In this, inter alia, a transformer core 2 which is under construction is arranged, which in the example shown consists of a yoke with 5 legs. Also in the work area 14 are 1 2 recording stack 50.1 ... 50. The receiving pel 50.1 ... 1 2 are aligned so that an orientation of the stacked transformer sheets 3 corresponds to their orientation in the transformer core 2 to be built, d. H. an orientation of the Aufna hmesta pel 50.9 ... 1 2 for the yoke plates is perpendicular to an orientation of the other recording stack 50th 1 ... 8 for the leg plates. Four recording stacks 50. 1 ... 4; 50.5 ... 8 are arranged laterally outside the transformer core 2, parallel to the legs of the core; The four last Aufnahmesta pel 50.9 ... 1 2 are placed parallel to the yoke of the transformer core 2 and this adjacent.

Furthermore, there are three alignment tables 5 1, 52, 53 in the working area 14. Individual sheets 3 can be placed thereon and positioned correctly so that they are then moved onto the transformer core 2 by one of the grippers 20, 30, 40 in a positionally accurate transport operation can. Such alignment tables are known in principle, they can be based, for example, on mechanical stops and / or optical image acquisition and corresponding positioning means.

The receiving stacks 50, 1... 1 2 and the alignment tables 5 1, 52, 53 are each assigned to one of the grippers 20, 30, 40 as follows: Gripper pickup stack Aligning table sheets

20 50. 1 ... 4 5 1 thigh

30 50.5 ... 8 52 thighs

40 50.9 ... 1 2 53 Yoke

The alignment tables 5 1, 52 for the leg plates are located between the corresponding storage stacks 50. 1 ... 4, 50.5 ... 8 and the transformer core 2, the alignment table 53 for the yoke plates is with respect to the transformer core 2 behind the corresponding storage stacks 50.9 ... 1 2. The orientation of the holding surfaces of the grippers 20, 30, 40 is respectively adapted to the orientation of the sheets 3 to be transported, d. H. the longitudinal direction of the holding surfaces of the grippers 20, 30 for the leg plates is perpendicular to the longitudinal direction of the holding surface of the gripper 40 for the yoke plates. The latter gripper 40 is arranged on the central bridge 1 2, the other two grippers 20, 30 on the outer bridges 1 1, 13th

The metal sheets 3 are deposited on the stacking stacks 50. 1 ... 1 2, ie the metal sheets 3 are stacked on top of each other so that they or positioning holes arranged thereon are precisely aligned. Before a first sheet 3 is removed, the exact position (automatically or manually) is determined. For this purpose, for example, one of a respective gripper 20, 30, 40 arranged laser light source e witnessed laser point manually to a predetermined location on the uppermost sheet 3, z. B. are moved to a positioning hole. This process can be repeated for a second location. Subsequently, the position of the sheet stack is precisely known and can be used in the course of the further process. The laser light source can be used simultaneously to determine a distance between the gripper and an underlying Sta pel. In addition, for control purposes, the stack can also be detected optically by means of a camera arranged on the gripper. By means of the portal 1 and the grippers 20, 30, 40 arranged thereon, individual sheets 3 can then be automatically removed from the stacking stacks 50.1... 1 2 and transported in exact position and deposited on the transformer core 2, which is formed of a plurality of stacking stacks. If necessary, a sheet 3 from the gripper 20, 30, 40 stored on the corresponding alignment table 51, 52, 53, where correctly positioned, in turn, detected by the corresponding gripper 20, 30, 40 and transported to the transformer core 2.

Figure 2A is a schematic oblique view of a gripper for gripping a sheet. FIG. 2B is a section of FIG. 2A showing the suction grippers and the positioning pins. FIG. 2C is a schematic side view of two suction grippers and one positioning pin.

The gripper 20 comprises a support structure 2 1, which is indicated in the illustration like a frame. The support structure 2 1 is connected to the carriage mounted on the portal in a conventional manner. On the underside of the support structure 2 1 a number of suction pads is arranged. In FIGS. 2, 4, 5 and 6, only a few of these suction grippers are shown in favor of improved clarity; in an actual embodiment, a number of further suction grippers are provided so that the sheets 3 can be reliably detected and held. For example, a typical gripper has about 40 suction pads. The suction pads define a holding plane. The suction gripper or a subset of the suction pads, especially in outer sections of the gripper, can be moved back individually or in groups behind a holding plane to prevent them from colliding with other structures when handling smaller sheets 3, such. B. the flanges of clamps in the region of the transformer core to be built. The corresponding stroke can be approx. 100 - 400 mm. Also, the suction pads can be arranged individually or in groups in the holding plane displaced, so that the gripper can be easily adapted to the contour of the sheets to be transported.

In the simplified illustration according to FIGS. 2A-C, four suction grippers 22. 1... 22. 4 are arranged, which are arranged in a row along a central longitudinal axis of the gripper 20 (and thus of the sheet 3 to be transported). Between each two of the Suction gripper 22.1, 22.2 or 22.3, 22.4 is a positioning pin 60. 1, 60.2 movably mounted in a direction perpendicular to the holding plane. This has, as described below, an inner pin, which can penetrate into positioning holes 3a of sheets 3 of a sheet stack. To adapt to different sheet geometries and the positioning pins 60. 1, 60.2 along with the immediately adjacent suction pads 22. 1, 22.2 or 22.3, 22.4 along the longitudinal axis of the gripper 20 can be moved.

Figures 3A, 3B show a cross-section and a side view of the positioning pin 60. This comprises a substantially cylindrical housing 6 1, in which an inner pin 63 is slidably mounted. The housing 61 forms a cylindrical shaft 62 with an outer diameter of almost 16 mm, the likewise cylindrical inner pin has an outer diameter of 3 mm. At its distal end, where the inner pin 63 exits, the shaft 62 tapers in a conical section 62a. The inner pin 63 is rounded at its free (distal) end 63a. The inner pin 63 is pressed by a coil spring 64 in its extended position. With an acting axial force, it can be approximately halfway into the housing 61 into it. If the axial force falls away, it moves due to the action of the coil spring 64 back into its extended position. This is defined by a stop 63b on the inner pin 63, which cooperates with a stop surface on the housing 61. An axial movement of the stopper 63b relative to the housing is also detected by an optical, electrical or mechanical sensor 65 and transmitted to a controller.

FIG. 4A shows a schematic oblique view of the gripper when shaking off adhering sheets, FIG. 4B shows a detail from FIG. 4A with the suction grippers and the positioning pins. FIG. 4C is a schematic side view of two suction grippers and one positioning pin during shaking off.

On the gripper 20, a sheet thickness gauge is arranged with a sensor (not shown). With this can be when picking up a sheet from the receiving stack after lifting the suction pad 22.1 ... 4 determine whether this is a single sheet. 3 hold or whether at the directly held sheet 3 one or more further sheets 3 'adhere. If this is detected, the gripper 20 is raised so far that the holding plane is located at a predetermined distance d to the top sheet on the receiving stack. The positioning pins 60.1, 60.2 are then arranged so that the inner pin 63 penetrates into the positioning holes 3a of the uppermost sheets 3 "on the receiving stack, a penetration depth being ideally about 2 mm, which corresponds to 6 sheets.

Next, the suction pads 22.1 ... 4 with a stroke h of, for example, 30 mm and a predetermined frequency of, for example, 5 Hz moves up and down, the actuation of the Sa uggreifer 22. 1 ... 4 can be done simultaneously or offset. It can also be driven alternately different movement pattern. The stroke h is generated by a pneumatic cylinder.

Due to the mechanical action, the sheet 3, which is gripped directly at the bottom, is shaken off due to adhesion, cohesion, partial vacuum, electrostatic or magnetic forces, and further sheets 3 'fall back onto the receiving stack. The inner pins of the positioning pins 60. 1, 60.2 ensure that the further sheets 3 'fall back in a positionally accurate manner onto the pickup stack and that the sheets 3 "on the pickup stack also retain their exact position.

It has been shown that fallen-back sheets adhere less well to the underlying sheets than those which have been pressed against the receiving stack for some time due to the weight of the sheets lying thereon. There is thus a high probability that no shaking is necessary when receiving the subsequent sheet (and possibly further sheets).

Figures 5A and 5B show a schematic oblique view and side view of the suction pads and a positioning pin in centering an uppermost portion of a stack of sheets.

A positionally accurate held on the gripper plate 3 is as follows a uf on the Ablagesta pel (which forms part of the transformer core to be formed) stored: First, the gripper with the sheet 3 with the help of the portal to the filing position Verfa hear. Of the Gripper with the sheet 3 is then lowered until the sheet reaches the receiving stack. With the suction pads 22.1 ... 4, a certain contact pressure is exerted on the sheet 3. As a result, in particular air remaining between the sheets is pressed out laterally. The positioning pins 60. 1, 60.2 are moved down until the inner pin 63 is received by the positioning holes of the sheet 3 to be deposited and the other sheets 3 "of the receiving stack.

In order to avoid an impairment of adjacent receiving stack of the transformer core, now arranged on jibs on the gripper hold-down can be lowered onto the adjacent receiving stack. The negative pressure on the suction pads 22. 1 ... 4 is now turned off, so that the suction pads 22.1 ... 4 can be moved upwards with the gripper by a certain distance, while the sheet 3 remains lying on the receiving stack. At the same time, the positioning pins 60.1, 60.2 are moved downwards by a corresponding relative movement of the cylinders carrying them, so that the inner pins 63 continue to penetrate the positioning holes 3a of the uppermost sheets 3, 3 "of the receiving stack 1. The positioning pins 60, 1, 60.2 then move on The tapered portion 62a comes into contact with the positioning holes 3a, and finally, the lowermost portion of the shaft 62 is inserted into the positioning holes 3a of the uppermost sheets 3, 3 ". As a result, a precise alignment of these sheets is achieved on each other. This precise alignment is restored several times, each time you place another sheet. Subsequently, the positioning pins can be withdrawn.

When placing the core, a clamp is first placed on the pivoting table, the bottom sheets can not be centered with the pin, so they go to the alignment table to get a well-defined position.

FIG. 6A is a schematic oblique view of the detection of misplaced sheets, and FIG. 6B shows a detail of FIG. 6A. When the gripper approaches the receiving stack, the positioning pin 60 .1 is positioned relative to the suction grippers 22. 1, 22. 2 such that the inner pin 63 protrudes beyond the holding plane. at On the receiving stack, the inner pin 63 can freely penetrate into the mutually aligned positioning openings of the sheets 3, 3 ', 3 ". However, if there is a mispositioning, as in the case shown in Figures 6A, 6B, the inner pin 63 abuts at one of the incorrectly positioned sheets 3 'and is pushed back into the shaft 62 on further lowering of the gripper.This is - as described above - detected by the sensor 65 and transmitted to a control unit.

As a result, the necessary measures can be taken. For example, the sheet 3 can be picked up with the gripper, then not directly moved to the corresponding storage stack, but first on an alignment table, where then the correct positioning is made by the gripper before re-recording.

In a lowermost region of the receiving stack, the inner pin 63 is pushed back even when correctly positioned on the receiving stack sheets because it comes into contact with the ground. However, this can be readily recognized on the basis of the known vertical position of the gripper so that a correction instruction only takes place when the contact with a sheet located above the background is detected.

Figure 7 is a schematic oblique view of the generation of a glue dot. On the underside of the gripper, a stamp 70 is arranged, which comprises a front-side stamp surface and a feeding device for an adhesive liquid. The stamp 70 comes when depositing a sheet 3 on the Aufna hmestapel with the top surface of the sheet in contact and generates by dispensing a certain amount of the adhesive liquid the glue dot 7 first Its height is max. 1 μηι. When placing and pressing the next sheet this adheres to the glue point 7 1 and is thereby prevented from moving relative to the underlying sheet. Instead of a single multiple adhesive dots can be generated.

Suitable as adhesive liquid is, for example Vaseline. This reliably prevents the top sheet from sliding away and is compatible with common transformer oils. The generation of a glue point is of great benefit in particular if no positioning holes are present and securing by means of a positioning pin is therefore not possible.

The invention is not limited to the illustrated embodiment. Thus, additional or different elements may be provided to prevent slippage of the receiving stack and or the storage stack when picking or laying of sheets. If sheets are handled without positioning holes, alignment on a respective alignment table may be mandatory. If there are positioning holes, the number of alignment tables can be reduced, taking care that all grippers should have access to the alignment table.

In general, the layout of the system, including arrangement of Aufna hmestapel, the transformer core to be built, the alignment tables and the gripper on the portal, be different from the example shown.

In summary, it should be noted that the invention provides a system and a method for automatically depositing sheets on a stack of stacks for the production of transformer cores, which allow an efficient and flexible positionally accurate transport of the transformer sheets.

Claims

claims

Apparatus for automatically depositing metal sheets on a storage stack for the production of transformer cores, comprising a transport device for positionally accurate transporting of individual sheets stacked on a receiving stack to the deposit pile, the transport means comprising a gripper for gripping a top sheet on the tray Aufnahmesta pel, for holding the sheet during transport and for depositing the sheet on the discard pile comprises, characterized by arranged on the gripper elements for maintaining a positioning stacked sheets on the Aufnahmesta pel and / or on the discard pile.

Installation according to claim 1, characterized in that the elements comprise at least one positioning pin for cooperation with a positioning hole in the sheets to be deposited.

Installation according to claim 2, characterized in that the positioning pin has a shaft and a shaft movably mounted in the inner pin.

Installation according to claim 3, characterized in that the inner pin is biased by spring means in a position extended relative to the shaft.

Plant according to claim 3 or 4, characterized in that the shaft and the inner pin each have a circular cross-section and that an outer diameter of the shaft is at least three times, preferably at least five times, an outer diameter of the inner pin.

Installation according to one of claims 3 to 5, dadu rch in that a sensor for detecting a repulsion of the inner pin is arranged relative to the shaft on the positioning pin.

7. Installation according to one of claims 2 to 6, characterized in that the gripper has at least two positioning pins which are arranged on a movable element along a longitudinal extent of the gripper.

8. Plant according to claim 7, characterized in that on the movable element, a laser source is arranged, which generates a light spot on a plate arranged parallel to the holding plane, wherein the light spot is generated such that it is aligned with a positioning hole of the sheet, if a correct Positioning of the corresponding positioning pin is reached.

9. Installation according to one of claims 1 to 8, characterized in that the gripper has a plurality of suction pads for detecting and holding the sheet.

10. Plant according to claim 9, characterized in that at least one of the plurality of suction grippers can be moved perpendicular to a holding plane of the gripper with a first stroke in a standby position behind the holding plane.

1 1. Plant according to claim 9 or 10, characterized in that at least one of the plurality of suction pads is perpendicular to a holding plane of the gripper with a second stroke back and forth bewegba r, so that there is a shaking movement of the detected sheet.

1 2. A plant according to claim 1 1, characterized in that the at least one of the plurality of suction pads is arranged on a lifting cylinder, wherein the lifting cylinder has an upper stop and the suction pad is moved back and forth so that it reaches the second stroke on Stop strikes, resulting in a shock.

1 3. Installation according to claim 1 1 or 1 2, characterized in that an actuation of a plurality of reciprocable suction gripper is independently controllable.

14. Installation according to one of claims 9 to 13, characterized in that at least one of the suction pads on the gripper is displaceable in the holding plane.

1 5. Installation according to one of claims 1 to 1 4, characterized in that the gripper a sheet thickness gauge with a sensor for detecting a number adhering to the gripper plates a ufweist.

1 6. Installation according to one of claims 1 to 1 5, characterized in that the gripper comprises a camera for optically detecting the stack.

1 7. Installation according to one of claims 1 to 16, characterized in that the gripper comprises a Absenkba Ren hold-down, which is absabba r when depositing the sheet on the discard pile on an adjacent stack to a position of sheets on this adjacent stack to to back up.

1 8. Installation according to one of claims 1 to 17, characterized in that the elements comprise at least one device to m generating a glue point on a located in a holding position with respect to the gripper plate.

1 9. Plant according to claim 1 8, characterized in that the device is designed as a Kleberapplikator.

20. Plant according to one of claims 1 to 19, characterized in that the transport device comprises a portal, in particular a surface portal, on which the gripper is movably mounted, wherein the portal detects a work area, which comprises the receiving stack and a building area for building the Transformer core includes.

2 1. Installation according to claim 20, characterized in that the gripper is mounted vertically movable on the portal.

22. Installation according to one of claims 1 to 2 1, characterized by at least two grippers, wherein a first of the at least two grippers for gripping yoke plates and a second of the at least two grippers for gripping leg plates is dimensioned.

23. Installation according to one of claims 1 to 22, characterized by an alignment table for positioning of sheets, wherein the gripper can place sheets on the alignment table and record from the alignment table.

24. A method for automatischen placing sheets on a discard pile for the production of transformer cores, wherein the sheets individually from a Pick pile directed stacked sheets removed, transported accurately positioned and stored on the Ablagesta pel, characterized in that when removing and / or dropping on the recording or discard pile under the removed or discarded sheet metal sheets are temporarily fixed to maintain their positioning ,

25. The method according to claim 24, characterized in that after removal of the sheet is determined by a sensor, whether the sheet adhered to further sheets and that the detected sheet is shaken by a gripping device, if the adhesion of further sheets is determined.

26. The method according to claim 25, characterized in that when shaking a positioning pin positioning holes in the detected sheet, penetrates the sheets to be shaken off and in sheets on the receiving stack.

27. The method according to any one of claims 24 to 26, characterized in that when placing the sheet on the discard pile a positioning pin is temporarily moved into positioning holes in the sheet to be deposited and in sheets on the discard pile.

28. The method of claim 26 or 27, characterized in that an abutment of a movably mounted in the positioning pin inner pin is detected to detect a mis-stacking of a stack.

29. The method according to any one of claims 24 to 28, characterized in that the sheet deposited at a detected mis-stacking on an alignment table, positioned on the alignment table and resumed.

30. The method according to any one of claims 24 to 29, characterized in that when depositing the sheet on the discard pile on a top of the deposited sheet a glue dot is generated.