Device and method for stacking stacked fiberboards

Abstract

Device and method by which fiberboards can be reliably, quickly and with very high consistency unstacked from a cuboid stack of fiberboards.

Description

[0001] The invention relates to a device and a method for stacking stacked fiberboards.

[0002] Fiberboard or fiber mats are typically delivered in large stacks, also known as bales. The fiber is usually cellulose. For further processing, for example in a machine for producing fiber webs, the fiberboards are fed into a shredder. For the cost-effective production of high-quality fiber webs, it is crucial that the fiberboards are fed into the shredder evenly, reliably, and at high speed. This requires separating a specific number of fiberboards from the bale, i.e., stacking them, which are then fed into a shredder or hammer mill.

[0003] Such devices and methods are known from the prior art. For example, DE 2 045 996 A1 discloses a method and a machine for continuously separating one or more sheets from a bale of paper, cardboard, or paper pulp. The device includes, among other things, a slightly inclined conveyor, a counter-support with groups of chain-guided support arms, a movable counter-support, and a cutting blade with a wedge-shaped side profile. During operation of the device, a bale is placed on the conveyor, with the sheets resting on their edges at a slight inclination to the vertical direction, and the bale being held at the sheet flat side by a first group of support arms. The counter-support also rests against the sheet flat side of the foremost sheet.In this position, the cutting blade moves downwards, encounters the bale, and finally penetrates it with its cutting edge, severing one or more sections from the bale as the counter-holder yields. Simultaneously, the first group of support arms is moved downwards by the chains. This releases the severed sections, which then fall and can be transported further. At the same time, the second group of support arms is moved into a position where they can support the remaining bale.

[0004] Other commercially available devices for unstacking fibrous bales employ various lifting mechanisms (see, for example, WO 2013 / 133913 A1 on page 7). Some devices include vacuum suction cups for lifting individual sheets. Others include clamping mechanisms that allow multiple sheets to be lifted. Still others include a pusher and an offset counter-holder, enabling one or more sheets to be pushed off the bale parallel to the sheet surface. Other devices include a multi-pronged fork that is inserted into the bale parallel to the sheet surface to lift one or more sheets from the bale.

[0005] Due to the varying nature of the fiber stacks, all known devices experience more or less significant problems during destacking, leading to impairments when a high degree of consistency and reliability of the destacking process is required.

[0006] For example, in the device disclosed in DE 2 045 996 A1, an uncertainty factor exists in that the plates fall onto an inclined conveyor belt after being released. A further problem can arise from the relatively strong deflection that occurs when the plates are released, as they are lifted from the remaining bale on one side by the cutting blade and pressed against the remaining bale on the other side by the support arms.

[0007] When using vacuum suction cups, the varying degrees of adhesion between individual plates can lead to an uncontrollable number of plates lifted during a single lifting operation, or to plates that have already been lifted falling back down or hanging unevenly. Similar problems can occur when using clamping mechanisms. Furthermore, significant deflection of the plates can occur if only a few plates are to be lifted. When using sliders, plates can fold or crease. With multi-pronged forks, the lowest lifted plate may not be held by all prongs; for example, a plate might hang down on one side if one or more prongs on that side fail to engage underneath it.

[0008] Furthermore, destacking devices for stacked plates are disclosed in documents EP 2 399 849 A1, DE 10 2005 062 713 A1 and EP 1 359 102 A1.

[0009] The object of the invention is to provide a device and a method with which fiberboards can be reliably, quickly and with very high consistency unstacked from a stack of fiberboards.

[0010] The problem is solved according to the invention by an embodiment according to the independent claims. Further advantageous embodiments of the present invention are found in the dependent claims.

[0011] The invention will be explained below with the aid of figures. The figures show, in detail: Fig. 1: Fiberboard and stack of fiberboard Fig. 2: Device according to the invention Fig. 3: First assembly for handling the stack or remaining stack in side view Fig. 4: First assembly view in x-direction Fig. 5: Split element in interaction with a stack Fig. 6: Holding and guiding element in interaction with a stack Fig. 7: Sliding element interacting with a stack Fig. 8: Details on the gap element and the holding and guiding element Fig. 9: Further embodiment of gap element and holding and guiding element Fig. 10: Self-alignment

[0012] It should be noted at the outset that the embodiments of the present invention described below have been optimized for stacking cellulose bales weighing approximately 250 kg (± 10%), with a dry matter content of approximately 95%, dimensions (L × W × H) of max. 1000 mm x 1000 mm x 600 mm, and a plate thickness of 0.8 to 2.8 mm. This applies particularly to the preferred dimensions specified below. However, it will not be difficult for a person skilled in the art to adapt the principle of operation according to the invention to other fiber materials and bale dimensions based on the technical teaching disclosed in this document, without having to make any inventive contributions.

[0013] Fig. Figure 1 shows a fiberboard, labeled 1, on the left. The fiberboard 1 is approximately cuboid in shape, with the deviations being due to the manufacturing process and not intentional. The approximately cuboid shape applies when the fiberboard rests on a flat surface, as shown in Figure 1. Fig. Figure 1 shows that when the fiberboard is lifted from this base, it generally deforms. The extent of the deformation depends on how the lifting or holding device supports the board during lifting. The deformation also depends on the board's stiffness and its basis weight. The board's distinctive shape results from its very low height compared to its length and width. Such a board therefore has two large surfaces, one of which is called the base, and the opposite side the top. The four smaller surfaces are called the side faces or simply the sides. The base can be approximately square or rectangular. In the latter case, the length differs significantly from the width of the fiberboard.

[0014] On the right side of the Fig. Figure 1 shows a stack of such fiberboards, labeled 2. Such a stack is also called a bale. At the bottom is a first fiberboard, and above it is at least one further fiberboard, with each subsequent fiberboard resting with its base on the top surface of the fiberboard below it. The base of the bottom board forms the base or underside of the stack 2. Since the fiberboards are stacked with the same orientation of their bases, the stack itself has an approximate cuboid shape. The individual boards are compressed by gravity, with the compressive force increasing from top to bottom. Static and sliding friction between the compressed board surfaces counteracts any displacement of the boards parallel to their bases. Without additional retaining elements, such a stack has only limited stability against tipping from the... Fig. Orientation shown in Figure 1. As the tilt angle increases, the top plates in particular tend to slide off the stack.

[0015] In the middle of the Fig. Figure 1 shows the coordinate system used in this document. The z-direction corresponds to the stacking direction or the surface normal on the top or bottom surface of the plates. The x-direction points towards a side surface, and the y-direction points towards an adjacent side surface perpendicular to it. In this document, the x-direction is also referred to as the feed direction, since plates removed from the stack are primarily moved in this direction by the device according to the invention. If the plates have rectangular bases, the x-direction can be aligned along either the longer or the shorter side. However, it is advantageous for the x-direction to be aligned along the shorter side, as the required feed stroke when removing the plates is then less than when the x-direction is aligned along the longer side. This will be described in more detail below.The feed direction x defines a front and a back side of the stack of plates 2. The remaining surfaces of the stack 2, i.e., the surfaces that are not the base, top, front, or back, are referred to simply as "sides".

[0016] After at least one fiberboard has been removed from the stack, the remaining stack is called the residual stack. Towards the end of the unstacking process, the residual stack may consist of only one fiberboard.

[0017] Fig. Figure 2 shows a highly schematic representation of a device according to the invention. The device contains a stack of fiberboard panels, which is designated 2. The device comprises a first assembly, which is responsible for handling the stack or the remaining stack after fiberboard panels have been unstacked, and a second assembly, which is responsible for handling fiberboard panels to be unstacked. The first assembly is designated 3 and the second assembly is designated 4. The individual elements of the assemblies are explained in more detail in connection with the following figures. It should be mentioned in advance that the first assembly is designed such that it can move the stack or remaining stack 2 in the x-direction, indicated by the horizontal arrow above the stack, and in the z-direction, indicated by the vertical double arrow below. The device according to the invention comprises further elements.This includes, for example, a control device, which is indicated by the rectangle labeled 5. The control device 5 is designed such that it can control the elements of the first and second assemblies, i.e., the handling of the stack or remaining stack 2 and the handling of the plates to be removed.

[0018] Fig. Figure 3 shows elements of the first assembly 3 for handling the stack or remaining stack 2. The first assembly 3 is shown from the side. The first assembly 3 comprises a conveying device, which is designated 3.1. The stack 2 is picked up by the conveying device 3.1 by resting its base on the conveying device 3.1 and can be moved by it in the x-direction. The conveying device 3.1 is also designed so that it can be moved in the z-direction. In this way, the stack 2 picked up by the conveying device 3.1 can be moved in the z-direction.

[0019] The first assembly 3 also includes a counter-support, which forms a stop to limit the movement of the stack 2 in the x-direction. The counter-support is in Fig. 3 is labelled 3.2. In Fig. In this embodiment, the counter-support 3.2 is designed to extend over the entire height of the front of the stack 2. This is an advantageous embodiment because it prevents the stack 2 from becoming stuck with its front against the counter-support 3.2 when moved in the z-direction. However, the counter-support could also be designed to extend only over a portion of the stack 2's height where the top plates are located. The number of top plates swept over by the counter-support 3.2 depends on the number of plates to be removed in a cycle. The number N of plates that can be stacked in a cycle using a device according to the invention is at least one plate and is not limited from above. In the application tested in detail by the inventors, the number of plates removed ranged from N = 5 to 20.The counter-support should in any case extend over at least N + 2 of the uppermost plates.

[0020] The counterholder 3.2 includes a release element which is located in Fig. The release element 3.3 is designated as such. Its function is to allow the lifted plates to move in the x-direction. Release element 3.3 can assume two positions. In the first position, release element 3.3, like the counter-holder 3.2, generally blocks the x-direction for the plates to be unstacked. In the second position, release element 3.3 releases the x-direction for the plates already lifted from the stack. The plates in the remaining stack are still prevented from moving in the x-direction by the counter-holder 3.2.

[0021] In Fig. Figure 3 shows two different embodiments of the release element 3.3. The portion of the counterholder 3.2 outlined by the dashed circle is shown enlarged on the right side. In the first preferred embodiment, the release element 3.3 can be pivoted. In the first position, the release element 3.3 forms, so to speak, the straight extension of the lower portion of the counterholder 3.2 (as shown in the dashed circle on the left side of the figure). The release element is moved into the second position by a pivot of approximately 90° (as shown in the middle section of the figure). Fig. (3 shown). In this position, the release element 3.3 opens the path in the x-direction and simultaneously forms a sliding element for the movement of the stacked plates in the x-direction over the counter support 3.2. A pivotable release element 3.3 can advantageously include a toggle lever and be pivoted by a pneumatic cylinder.

[0022] Far right in Fig. Figure 3 shows the second embodiment of the release element 3.3. In this embodiment, the release element can be moved in the z-direction. In the first position, the release element is in the lower position, and in the second position, the release element 3.3 is in the upper position. Fig. Figure 3 on the far right shows the release element 3.3 in its upper position, in which a gap opens between the lower part of the counter-support 3.2 and the release element 3.3, through which the stacked plates can be moved in the x-direction. In the lower position of the release element 3.3, this gap is closed. A release element 3.3 that can be moved in the z-direction can advantageously be moved with a pneumatic cylinder.

[0023] It is advantageous if the release element 3.3, in its first position in the z-direction, has its upper edge at least flush with the upper edge of the stack to be destacked, and preferably projects beyond it as shown in the Fig. 3 shown.

[0024] In a preferred embodiment, the first assembly 3 comprises at least two position sensors, designated 3.4 and 3.5. Embodiments that function without or with only one position sensor are described below in connection with the method according to the invention. The first position sensor 3.4 serves to align the stack 2 at the beginning of the destacking process. For this purpose, the first position sensor 3.4 is designed such that it can detect when the front of the stack 2 is in contact with the counter-support 3.2. When this occurs, the conveying of the conveyor unit 3.1 can be deactivated. The second position sensor 3.5 is designed such that it can detect when the top of the stack or remaining stack 2 assumes a predefined position in the z-direction. The predefined position determines the number N of plates that are destacking in a destacking cycle.

[0025] The first position sensor 3.4 can advantageously be designed as a switch which is actuated when the stack 2 moves against the counter-holder 3.2. It can also be designed as a non-contact distance sensor, e.g., a radar sensor. The same applies to the second position sensor 3.5. If it is designed as a switch, then it must be movable in the z-direction if the number of plates to be destacked in a cycle is to be varied. The z-position of the position sensor 3.5 can be set manually or automatically by the control device 5, with the automated setting being preferred. However, it is particularly preferred to design the second position sensor 3.5 as a non-contact distance sensor, since then setting its z-position is not necessary. Furthermore, the second position sensor 3.5 can then be...5. The stacking process is not impeded, as it can be positioned at a sufficiently large distance from the top of stack 2.

[0026] Fig. Figure 4 shows elements of the first assembly 3 viewed from the rear of the stack 2 in the x-direction. In the particularly advantageous embodiment shown, the conveying device 3.1 is designed as a 3-chain conveyor. The additional support in the middle prevents the plates from sagging in the central section, which could occur especially when a large portion of the plates has already been unstacked.

[0027] Sagging could also be avoided by supporting stack 2 from below with an additional stable base plate. In this case, the conveyor 3.1 could consist of only two laterally arranged chain drives (or other types of drives). The device would then either need to include additional elements that allow the base plate to be removed from the device after the entire stack 2 has been unstacked (e.g., a gripper arm or similar), or the counter-support 3.2 could provide sufficient space in its lower section to allow the base plate to be conveyed out in the x-direction by the conveyor 3.1 itself. If necessary, the conveyor 3.1 could also be moved very far downwards, i.e., in the negative z-direction, to bypass the counter-support 3.2 when ejecting the base plate from below. The base plate could also be removed manually.In any case, the underside of the base plate, if one is present, forms the base of stack 2 and is therefore also part of stack 2. The base plate can be of any design, as long as it fulfills the aforementioned function (preventing sagging) and does not impede the procedure described in this document.

[0028] In the Fig. In the embodiment shown in Figure 4, the counter-holder 3.2, including the release element 3.3, is designed in two parts, with the two parts being arranged in the area between the chain conveyors so that the counter-holder 3.2 does not interfere with them, even if the counter-holder 3.2 extends over the entire height of the stack 2. The conveying device 3.1 could also comprise more than three chain conveyors.

[0029] Fig. Figure 5 shows a first element of the second assembly 4 for handling plates to be lifted or stacked. This is a so-called splitting element, which is located in the upper area of ​​the Fig. Figure 5 is shown schematically in side view, i.e., viewed in the y-direction, and is labelled 4.1. Viewed from the side, the slit element has a wedge-shaped form and can be moved in the x-direction, as indicated by the double arrow below slit element 4.1.

[0030] The remaining parts of the Fig. Figure 5 shows the split element 4.1 and how it interacts with the plates of stack 2. To keep the representation simple, the special case is considered where only a single plate (N = 1) is to be destacked in a destacking cycle. In practice, more than one plate is usually destacked in a cycle.

[0031] Two cases are distinguished: In the first case, which occurs in the left parts of the Fig. As shown in Figure 5, the plates have high stiffness, so they sag relatively little. In the second case, on the right side of Figure 5, the plates have high stiffness, so they sag only a relatively small amount. Fig. As shown in Figure 5, the plates are less rigid and therefore sag much more. The two cases are each shown in two different views, which are identified by the coordinate systems shown in the middle: the view from the rear in the x-direction at the bottom and the side view above it.

[0032] To separate the plates to be removed from the remaining stack, the splitting element 4.1 is first driven into the stack from the rear and approximately midway between two adjacent plates stacked on top of each other in the y-direction. For this to work, the z-position of the stack must first be adjusted accordingly by the lifting and lowering function of the conveyor 3.1, as described above. The splitting element comprises two working faces that taper towards each other in a wedge shape in the y-direction to form a cutting edge at their point of contact. After the splitting element 4.1 is inserted into the stack, the first working face is oriented towards the plate(s) to be removed, and the second working face is oriented towards the remaining stack. The second working face preferably lies entirely within an xy-plane so that no significant forces are exerted on the remaining stack when the splitting element 4.1 is driven in.The two effective sides form an acute angle in the y-direction, which is less than 45°. The acute angle preferably lies in the range of 10° to 30°.

[0033] The gap element 4.1 can be used as in Fig. 5 shown as a wedge. In this case, the cutting edge of the splitting element 4.1 extends in the y-direction over the entire width of the splitting element 4.1. To ensure that the splitting element 4.1 can reliably penetrate between two adjacent plates, even with slightly wavy plates, it is advantageous if the cutting edge of the splitting element 4.1 is not too long in the y-direction. For the application mentioned above, practical values ​​of 10 to 100 mm proved to be suitable for the cutting edge length. However, the splitting element 4.1 can also be designed like the parting-off blade from DE 2 045 996 A1 (see the Fig. 3, Fig. 4 and Fig. 5 of document DE2 045 996 A1). In this case, viewed in the y-direction, the cutting edge is less wide than the splitting element at its base, where it is attached by a push rod. Furthermore, document DE 2 045 996 A1 indicates in Fig. 3. In the illustrated embodiment (“parting blade”) of the splitting element, the first working side has a special curved shape. The advantage of a smaller cutting width can also be achieved by having a wedge-shaped splitting element with sides that taper inwards in the x-direction. Such a splitting element is shown in the Fig. Figure 5 of this document is shown in top right in a top view. The cutting edge is labelled 4.1.1. The side of the splitting element 4.1 opposite the cutting edge 4.1.1 forms its base and is labelled 4.1.2.

[0034] In any case, the cutting edge 4.1.1 can advantageously be sharp and deburred or rounded, with the radius being less than 1 mm and preferably 0.2 to 0.5 mm.

[0035] When the splitting element 4.1 penetrates the stack 2, the release element 3.3 is in the initial position where it blocks the path in the x-direction for the uppermost plates of stack 2, preventing them from being significantly displaced in the x-direction by the penetration of the splitting element 4.1. This applies particularly to the plates that are split off in the process, but also at least to the plate immediately below them and potentially to further plates below that, so that the remaining stack does not change its position, or at least not significantly, when the splitting element 4.1 penetrates.

[0036] In the case of the comparatively stiff plates (left side of the Fig. 5) The detached plates are lifted from the remaining stack over a large part of their base area simply by the penetration of the splitting element 4.1. Only in the vicinity of the release element 3.3 does the lowest detached plate touch the remaining stack. In the case of the less stiff plates (right side of the Fig. 5) The lowest detached plate still rests on the remaining stack over a large area with its base. In any case, a gap forms around the cleavage element 4.1 in stack 2. This gap is crucial for the next step of the destacking cycle, which is related to the Fig. 6 is described.

[0037] The height and extent of the gap can be influenced not only by the width (y-direction) of the gap element 4.1 but also by its height (z-direction). For the application described above, a height of at least 50 mm for the gap element 4.1 has proven advantageous, preferably a height of 80 to 160 mm.

[0038] In any case, the use of exactly one splitting element 4.1 ensures that a defined number of plates are split off, i.e., the problem described above for the known device, which uses a multi-pronged fork to lift the plates, is avoided.

[0039] Fig. Figure 6 shows a second element of the second assembly 4 for handling plates to be lifted or stacked. This is a so-called holding and guiding element, which is located in the upper area of ​​the Fig. Figure 6 is shown schematically in side view, i.e., viewed in the y-direction, and is labeled 4.2. The holding and guiding element 4.2 can be moved in the x-direction, as indicated by the double arrow. The representation of Fig. 6 corresponds to that of Fig. 5. Additionally, the Fig. 6 in the lower row, the holding and guiding element 4.2 in top view.

[0040] In any case, the holding and guiding element 4.2 is inserted from the rear of the stack 2 (i.e., in Fig. 6 from the left) in the x-direction into the gap created by the gap element 4.1. This movement ends before or at the latest when the holding and guiding element 4.2 touches the release element 3.3. During this movement, the release element 3.3 remains in the initial position in which it blocks the path in the x-direction for the uppermost plates of stack 2. The upper row of subfigures of the Fig. Figure 6 shows the holding and guiding element 4.2 in this final position. The holding and guiding element 4.2 comprises two parts, which can be referred to as wings. These wings are arranged around the splitting element 4.1 in the x-direction, i.e., one wing is arranged on each side of the splitting element 4.1. The function of the wings of the holding and guiding element 4.2 is to hold the split plates in such a way that they have as little contact as possible with the remaining stack. For this purpose, the wings can be adapted to the stiffness of the plates, as shown in the lower two rows of the partial figures. Fig. 6 emerges.

[0041] In the case of rigid plates, they essentially only need to be lifted from the rest of the stack near the release element 3.3 and held at a distance from it. For this purpose, it suffices if the wings are narrow in the y-direction. Furthermore, the wings can be spaced further away from the position of the gap element 4.1 in the y-direction, since the gap created by the gap element 4.1 extends relatively far in the y-direction (see Figure 3). Fig. 5 bottom left).

[0042] In the case of less stiff plates, the gap created by the gap element 4.1 is significantly narrower in the y-direction (see figure). Fig. 5 (bottom right), therefore the wings must be closer to the split element 4.1 at least at their front end in the y-direction. Furthermore, the wings must extend far enough outwards in the y-direction to lift the side parts of the detached plates from the remaining stack and keep them at a distance. As shown in the partial figure of Fig. As can be seen in Figure 6, which is located at the bottom right, the leading edges of the wings are shaped so that they first penetrate the gap close to the splitting element 4.1 and then, as they continue to penetrate, gradually widen the gap with their diverging flanks. This lifts the detached plates from the remaining stack over a large area and keeps them at a distance. Only at the leading edges of the detached plates can they still touch the remaining stack.

[0043] Fig. Figure 7 shows a third element of the second assembly 4 for handling plates to be lifted or stacked. This is a so-called sliding element, which is located in the upper area of ​​the Fig. Figure 7 is shown schematically in side view, i.e., viewed in the y-direction, and is labeled 4.3. The sliding element 4.3 can be moved in the x-direction, as indicated by the double arrow. The representation of Fig. 7 corresponds to that of Fig. 5.

[0044] The sliding element 4.3 serves to move the plates, which were separated and lifted from the remaining stack in the preceding steps, at least partially in the x-direction over the lower part of the counter-support 3.2, thereby completing the respective cycle of the destacking process. For this purpose, the release element 3.3 is first moved into the second position, thus clearing the path for the lifted plates in the x-direction. The upper row of the partial figures of Fig. Figure 7 shows the release element 3.3 already in this position. If the sliding element 4.3 is now moved from the rear edge of the plates in the positive x-direction, it pushes the lifted plates ahead of it, so that they then protrude at least partially beyond the lower part of the counter-support 3.2 in the x-direction. In this position, the lifted plates could already interact with an additional conveying device, which is arranged in the x-direction behind the counter-support and which is Fig. 7 not shown and which is also not part of the device according to the invention. This additional conveying device could be designed as a conveyor belt or as a chain drive and exert a tensile force on the advanced plates so that the sliding element 4.3 does not have to push the plates further in the x-direction. A pivotably designed release element 3.3, as shown in Fig. Figure 7 shows how the plates are guided or supported from below during this process, which can be particularly advantageous with less rigid plates. It is advantageous if the release element 3.3 in the second position is aligned with the top edge of the remaining stack or positioned slightly lower.

[0045] In any case, the lifted plates are held and guided by the wings of the holding and guiding element 4.2 during the sliding process. For this purpose, it is advantageous if the wings have a smooth upper surface. It is also advantageous if the wings are chamfered or rounded, at least at their leading edge. Optionally, rollers can be arranged, particularly at the leading edge of the wings, projecting in the z-direction beyond the surface of the wings to further facilitate the sliding process through their rolling action.

[0046] In the above-mentioned application, it has proven advantageous if the wings of the holding and guiding element 4.2 have a width (y-direction) of 40 to 200 mm, preferably of 50 to 70 mm, and a thickness (z-direction) of 8 to 35 mm, preferably of 12 to 20 mm.

[0047] The design of the sliding element 4.3 can be adapted to the stiffness of the plates. For plates with high stiffness, it can be advantageous if the sliding surface of the sliding element 4.3 is designed in two parts, with the two parts of the sliding surface engaging the outer edge of the plates in the y-direction, as shown in the lower left of the figure. Fig. as shown in Figure 1. The two parts of the sliding surface could just as easily be arranged in the spaces between the wings of the retaining and guiding element 4.2 and the gap element 4.1. For panels with lower stiffness, it can be advantageous if the sliding surface of the sliding element 4.3 is as large as possible so that it can act on as much of the rear side of the lifted panels as possible. For this purpose, recesses can be provided for the wings of the retaining and guiding element 4.2. A recess could also be provided for the gap element 4.1. However, the sliding element 4.3 may also not include a recess for the gap element 4.1, as shown in Figure 1. Fig. Figure 7 is shown at the bottom right. In this case, the gap element 4.1 moves along with the sliding element 4.3 during the sliding process. Both elements 4.1 and 4.3 can also be connected to each other.

[0048] Fig. Figure 8 shows details of the gap element 4.1 and the retaining and guiding element 4.2. These elements are shown in a view along the x-direction. According to the invention, it is advantageous if the gap element 4.1 projects beyond the retaining and guiding element in both the positive and negative z-direction. The corresponding excess dimensions are designated A and B. A is the distance from the lower edge of the gap element 4.1 to the lower edge of the retaining and guiding element 4.2, and B is the distance from the upper edge of the gap element 4.1 to the upper edge of the retaining and guiding element 4.2. These distances are measured in the z-direction.

[0049] The distance A ensures that the holding and guiding element 4.2 does not come into contact with the remaining stack when inserted into the gap. Furthermore, a sufficiently large distance A ensures that the plates to be destacked are lifted sufficiently far from the remaining stack by the holding and guiding element 4.2. In the application described above, a distance A of at least 1 mm (preferably 5 to 20 mm) has proven advantageous.

[0050] The distance B ensures that the plates to be stacked are separated sufficiently in the positive z-direction by the gap element 4.2, creating a gap that allows for reliable insertion of the holding and guiding element 4.2. In the application described above, a distance A of at least 40 mm (preferably 70 to 140 mm) has proven advantageous.

[0051] It is also advantageous if the holding and guiding element 4.2 is designed so that its position in the z-direction can be adjusted. In this way, the distances A and B can be varied and adapted to the application. This can be achieved very simply, for example, by attaching the holding and guiding element 4.2 using elongated holes aligned in the z-direction.

[0052] Fig. Figure 9 shows another embodiment of elements 4.1 and 4.2. In this embodiment, these elements form a unit, i.e., the wings of the retaining and guiding element 4.2 are firmly connected to the gap element 4.1. Fig. Figure 9 shows this assembly in two views, which are characterized by the corresponding coordinate axes. In this embodiment, the gap element 4.1 is extended in the negative x-direction so that the wings can be attached to this extension of the gap element 4.1. The gap element 4.1 projects beyond the leading edge of the wings in the positive x-direction. To allow the wings to be inserted as far as possible into the stack, it is advantageous if, in this embodiment, the release element 3.3 has a recess or gap so that the tip of the gap element 4.2 is not obstructed by the release element 3.3 during the movement of the assembly in the x-direction. In this embodiment, the extended gap element 4.1 acts similarly to the holding and guiding element 4.2 by holding the plates to be stacked in the center (viewed in the y-direction) and guiding them during the sliding process.

[0053] It should also be mentioned that the x-movement of elements 4.1, 4.2, and 4.3 can be advantageously achieved by linear actuators. Pneumatic cylinders are preferably used for this purpose, as they enable rapid movements and thus short cycle times for high productivity.

[0054] Since the splitting element 4.1, in embodiments where it is not rigidly connected to other elements (4.2 or 4.3), only needs to penetrate a short distance into the stack, the movement in the x-direction could also be achieved by attaching the splitting element 4.1 to a pivotable lever. The pivot axis of the lever then lies in the y-direction. When the lever is pivoted, the splitting element 4.1, attached to the free end of the lever, performs an arc-shaped movement. The x-component of this arc-shaped movement then represents the required movement in the x-direction of the splitting element 4.1. If the position of the pivot axis is adjustable, it can be adapted to different stack lengths (x-direction). The movement of the splitting element 4.1...1. A pivotable lever offers the advantage that, immediately after penetration into the stack, the movement in the x-direction is accompanied by a slight movement in the positive z-direction, thereby widening the gap in this direction, i.e., making it wider than with a pure movement in the x-direction of the gap element 4.1.

[0055] The inventive method for destacking stacked fiberboards is described in detail below. An initial state is assumed in which a stack of fiberboards rests with its base on the conveyor device, with one side – the front – of the stack pointing in the x-direction. Furthermore, the stack should rest centrally on the conveyor device in the y-direction. The inventive method exhibits a certain tolerance with respect to the accuracy of these alignments (su and Fig. 10 for self-alignment). However, the deviations should not be too large, as this can increasingly hinder the sliding process. The release element 3.3 is in its first position. Elements 4.1, 4.2, and 4.3 are in a starting position. In this starting position, they are positioned in the negative x-direction far enough away from the counter-support that a stack of fiberboard can easily be placed between elements 4.1, 4.2, 4.3, and the counter-support. The steps listed below are preferably performed automatically and controlled by the control unit.

[0056] The process runs cyclically, with a predefined number of fiberboards being unstacked in each cycle. This predefined number of fiberboards is referred to, as above, as the "fiberboards to be unstacked". The first cycle executed, i.e., the initial cycle, and the last cycle executed, i.e., the final cycle, each differ from the cycles executed in between.

[0057] The initial cycle of the inventive method for stacking stacked fiberboards comprises the following steps: S1: Moving the conveyor in the z-direction so that the top of the stack occupies a predefined position in the z-direction; S2: Moving the stack in the x-direction using the conveyor device until the front of the stack rests against the counter-holder; S3: Moving the splitting element in the x-direction so that the splitting element penetrates the stack and splits the fiber sheets to be destacked from the remaining stack, creating a gap between two adjacent fiber sheets; S4: Inserting the holding and guiding element into the gap, whereby the holding and guiding element is moved in the x-direction to lift the fiberboards to be stacked from the remaining stack; S5: Moving the release element to its second position; S6: Moving the sliding element in the x-direction so that the fiberboards to be stacked are pushed by the sliding element in the x-direction until they protrude at least partially in the positive x-direction beyond the counter-holder.

[0058] It is advantageous to execute steps S1 to S6 in the specified order. However, it is also possible for steps S1 and S2 to be executed in reverse order or simultaneously.

[0059] The process then continues with as many further cycles as necessary to destack almost the entire stack. Before each subsequent cycle, elements 4.1, 4.2, and 4.3 are moved to their starting positions, and the release element 3.3 is moved to its first position.

[0060] The subsequent cycles comprise the following steps: S1: Moving the conveyor in the z-direction so that the top of the stack occupies a predefined position in the z-direction; S3: Moving the splitting element in the x-direction so that the splitting element penetrates the stack and splits the fiber sheets to be destacked from the remaining stack, creating a gap between two adjacent fiber sheets; S4: Inserting the holding and guiding element into the gap, whereby the holding and guiding element is moved in the x-direction to lift the fiberboards to be stacked from the remaining stack; S5: Moving the release element to its second position; S6: Moving the sliding element in the x-direction so that the fiberboards to be stacked are pushed by the sliding element in the x-direction until they protrude at least partially in the x-direction beyond the counter-holder.

[0061] This means that step S2 is omitted in the subsequent steps.

[0062] The final cycle, which is executed when the remaining stack has become so small that it comprises only the predefined number of fiberboard panels to be destacked or less, differs from the preceding cycles. Several possibilities exist.

[0063] If the stack does not include a solid base plate, step S1 can be modified by moving the conveyor in the z-direction to its upper end position. Step S3 is then omitted, and step S4 is modified since there is no longer a gap. In this case, the holding and guiding element can simply be inserted under the bottom fiberboard. Steps S5 and S6 are performed unchanged. Afterward, or concurrently with these steps, the conveyor can be moved in the z-direction to its lower end position to restore the initial state.

[0064] If the stack includes a fixed base plate, step S1 is modified if the number of plates remaining in the stack is less than the predefined number of plates to be destacked. Additionally, step S3 is modified by inserting the gap element between the bottom fiber plate and the base plate. The base plate could also advantageously have a recess into which the lower edge of the gap element can enter. Steps S4 to S6 are executed unchanged.

[0065] In any case, the conveyor can then be moved in the negative z-direction before or after step S6, so that it is ready to receive another stack.

[0066] Step S2 can advantageously achieve self-alignment of the stack. For this to work, the counter-support must be sufficiently stable. To illustrate this, [the following is shown]. Fig. Figure 10 shows a device according to the invention with a stack in three different states, each shown in a top view. The leftmost illustration shows the stack in the initial position, i.e., before the start of the method according to the invention. In this illustration, the stack is not optimally aligned on the conveying device 3.1, with the poor alignment being exaggerated for clarity. In practice, such poor alignment will hardly occur. The stack 2 is at an angle, i.e., twisted and not centered in the y-direction, i.e., off-center, on the conveying device 3.1. The gap element 4.1 is also in the initial position. In the middle illustration, the stack 2 was moved in the positive x-direction during the execution of step S2. This shows the point in time at which the stack 2 just touches the counter-holder 3.2 with its left front side. The illustrated device comprises two first position encoders 3.4, which are intended to indicate that the stack is in contact with the counter support 3.2. The counter support 3.2 is designed in two parts, and a first position sensor 3.4 is arranged on each part of the counter support 3.2. In the situation shown, neither of the position sensors 3.4 will give a signal indicating that the stack 2 is in contact with the counter support 3.2. Therefore, the conveying device 3.1 will continue to operate, pressing the stack against the counter support 3.2 on one side. This exerts a torque on the stack 2, which moves the stack 2 from its twisted position into the correct position with respect to the twist. This is shown in . Fig. Figure 10 is shown on the far right. The stack now rests against the counter-holder 3.2, so that both position sensors 3.4 deliver a corresponding signal. The control unit 5 now deactivates the conveying unit 3.1. However, the stack 2 is still off-center, so that in the next step S3, the gap element 4.1 would not penetrate exactly in the center of the back of the stack 2 with respect to the y-direction. The device according to the invention is tolerant of small off-center positions. However, if the off-center position becomes too large, it can happen that after step S4 the plates to be destacked remain connected to the rest of the stack on one side, so that the sliding operation in step S6 cannot be carried out correctly. In the Fig. In the case shown on the right, this problem could occur on the right side of the stack.

[0067] For the self-aligning effect described in the previous section, it is advantageous if the counter-support extends in the z-direction over the entire height of the stack, so that the counterforces emanating from the counter-support act on the entire stack. Otherwise, deformation of the stack may occur. Alternatively, the counter-support could also be constructed in multiple parts in the z-direction. For self-alignment to occur, at least one part of the counter-support would then have to be located in the lower part of the stack in order to exert the necessary counterforces on this part of the stack, which is also affected by the conveying device.

[0068] In order to detect unacceptably large decentering, a device according to the invention can include at least one additional position sensor which is arranged in such a way that it can monitor the position of the stack in the y-direction.

[0069] Steps S1 and S2 are preferably performed using position encoders 3.4 and 3.5. However, there are also embodiments in which none or not all position encoders are required.

[0070] For example, the conveyor 3.1 could be designed to move to defined z-positions. Since the initial stack height and the height of the remaining stack in subsequent cycles are known or can be calculated, the z-positions to be moved to by the conveyor 3.1 in step S1 can be calculated by the control unit 5, and the conveyor 3.1 can be controlled accordingly. This ensures that after moving to these z-positions, the condition required in step S1 ("that the top of the stack occupies a predefined position in the z-direction") is met. In this way, the second position sensor 3.5 can be omitted.

[0071] Step S2 could also be implemented by having the control unit 5 monitor the power consumption of the conveyor 3.1 during movement of the stack in the x-direction. If the power consumption increases above a predefined value, the front of the stack rests against the counter support 3.2. In this way, the first position sensor(s) 3.4 can be omitted.

[0072] It should be noted that all or some of the above-mentioned steps can be controlled by operators, i.e., performed manually. In these cases, position sensors can also be omitted if necessary. Step S2, in particular, lends itself to manual execution, as it only needs to be performed once per stack. This also offers the advantage that any incorrect stack alignment can be easily detected and thus avoided. The same applies to the final cycle, especially if the stack includes a fixed base plate.

[0073] Finally, it should be mentioned that it is advantageous if the device according to the invention is designed or oriented such that the z-direction coincides with the reverse direction of gravity, i.e., that the feed direction x is horizontal. However, it is also conceivable that the z-direction is inclined slightly against the direction of gravity. In particular, the device could be inclined so that the movements of the stack and the plates to be unstacked in the x-direction are partially assisted by gravity. However, there are limits to the possible inclination of the device relative to the direction of gravity, as problems arise if the inclination is too great. As already mentioned above, the stacks can become unstable if the inclination is too great, so that the entire stack can tip over, or individual plates can slide uncontrollably from the stack. Reference symbol list 1 fiberboard 2 stacks or bales of fiberboard 3 First assembly for handling the stack or remaining stack 3.1 Funding facility 3.2 Counterhold 3.3 Release element 3.4 First Position Giver 3.5 Second Position Giver 4 Second assembly for handling plates to be lifted 4.1 Split element 4.1.1 Cutting edge of a splitting element 4.1.2 Basis of a split element 4.2 Holding and guiding element 4.3 Sliding element 5 Control unit

Claims

Device for destacking stacked fiberboards (1) comprising a conveying device (3.1), a counter-holder (3.2) with a release element (3.3) and a gap element (4.1), wherein the conveying device (3.1) is configured to receive a stack (2) of fiberboards (1), and wherein the stack (2) comprises a base surface and a stacking direction of the stack (2) defines a z-direction, and wherein the release element (3.3) is configured to be movable between a first position and a second position, characterized in that the conveying device (3.1) is configured to receive the stack (2) by having its base surface rest on the conveying device (3.1), and to move the stack (2) in an x-direction perpendicular to the z-direction, and wherein the conveying device (3.1) is configured to be movable in the z-direction, and wherein the counter-holder (3.2) is configured to limit movement of the stack (2) in the positive x-direction, and wherein the gap element (4.1) is designed to be movable in the x-direction and is arranged such that the gap element (4.1) can penetrate the stack by a movement in the positive x-direction in order to split at least one fiber sheet (1) from the stack (2) by creating a gap between two fiber sheets (1), and wherein the release element (3.3) is designed such that in its first position it blocks movement of the at least one split fiber sheet (1) in the positive x-direction and in its second position releases movement of the at least one split fiber sheet (1) in the positive x-direction, and wherein the device comprises a holding and guiding element (4.2) movable in the x-direction and a sliding element (4.3) movable in the x-direction, and wherein the holding and guiding element (4.2) comprises two wings and is designed such that it can penetrate the gap with the wings by a movement in the positive x-direction, wherein one wing is arranged on each side of the gap element (4.1), and wherein the sliding element (4.3) is designed such that it can displace the at least one split fiber plate (1) by a movement in the positive x-direction when the wings of the retaining and guiding element (4.2) are in the gap and when the release element (3.3) is in its second position. Device according to claim 1, wherein the device comprises at least one first position transmitter (3.4) which is designed to output a signal when the stack (2) is in contact with the counter-holder (3.2). Device according to claim 1 or 2, wherein the device comprises a second position sensor (3.5) configured to output a signal when a side of the stack (2) located at the top in the z-direction assumes a predefined z-position. Device according to one of the preceding claims, wherein the conveying device (3.1) is designed as a 3-chain conveyor. Device according to one of the preceding claims, wherein the release element (3.3) is designed to pivot about an axis and can be moved from the first position to the second position by pivoting about the axis. Device according to claim 5, wherein the release element (3.3) is designed such that in its second position it can support a movement in the x-direction of the at least one split fibrous plate (1) by forming a sliding element for this movement. Device according to one of the preceding claims, wherein the gap element (4.1) and the holding and guiding element (4.2) are firmly connected to each other in order to be moved together in the x-direction. Device according to any one of the preceding claims 1 to 6, wherein the gap element (4.1) and the sliding element (4.3) are rigidly connected to each other in order to be moved together in the x-direction. A method for destacking stacked fiberboards (1), wherein the method is carried out by means of a device according to one of the preceding claims and comprises the following steps: S1: Moving the conveying device (3.1) in the z-direction so that the top of the stack (2) assumes a predefined position in the z-direction; S2: Moving the stack (2) by means of the conveying device (3.1) in the x-direction until the front of the stack (2) rests against the counter support (3.2); S3: Moving the splitting element (4.1) in the x-direction so that the splitting element (4.1) penetrates the stack (2) and splits the fiberboards (1) to be destacking from a residual stack (2), creating a gap between two adjacent fiberboards (1); S4: Inserting the holding and guiding element (4.2) into the gap, wherein the holding and guiding element (4.2) is moved in the x-direction to hold the fiberboards (1) to be destacking To lift fiberboards (1) from the remaining stack (2); S5: Moving the release element (3.3) into its second position;S6: Moving the sliding element (4.3) in the x-direction so that the fiber panels (1) to be stacked are pushed by the sliding element (4.3) in the x-direction until they protrude at least partially in the positive x-direction beyond the counter-holder (3.2). Device according to any one of claims 1 to 8, wherein the device comprises a control unit (5) which is designed to perform at least steps S1, S3, S4, S5 and S6 of the method according to claim 9.

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