Sheet Processing Machine

Abstract

A sheet processing machine having a transport mechanism for moving a sheet along a handling direction of the sheet processing machine and a waste ejection device (36) for ejecting the sheet. The transport mechanism comprises a sheet handling element (28) for moving the sheet, the sheet handling element (28) comprising at least one sliding element (54). The sheet handling element (28) is configured to eject the sheet as it passes through the waste ejection device (36). The waste ejection device comprises at least one alignment element (38) configured to interact with the at least one sliding element (54) to minimize deformation of the sheet handling element (28) as it passes through the waste ejection device (36).

Description

[Technical field]

[0001] The present invention relates to a sheet processing machine having a waste ejection device. [Background technology]

[0002] Sheet processing machines, also known as converting machines, are used in the packaging industry to process raw materials, such as cardboard, paper or foil, into intermediate or final products, usually in the form of sheets. Converting operations may include, for example, printing, cutting, creasing, blanking, foil stamping and / or fold-gluing. Typically, the individual operations are performed in subsequent processing stations of the sheet processing machine, and the sheets are transported from one processing station to the subsequent processing station by a transport mechanism.

[0003] For example, in a punching machine, so-called blanks can be obtained from sheets made from raw material. The blanking operation involves, for example, cutting off the cuts in the sheets by means of a blanking tool, the cuts being formed in a previous processing step, whereby the blanks are pushed downwards into a stacking area for recovering the blanks. The waste sheets therefore remain connected to the transport mechanism after the blanking operation and need to be removed in a subsequent waste discharge station (also called waste ejection station).

[0004] Modern sheet processing machines allow for high throughput of sheets, i.e., high processing speeds. In order to achieve such processing speeds, it is desirable to dynamically discharge waste sheets from the transport mechanism, i.e., to discharge waste sheets without having to stop the transport mechanism.

[0005] However, high processing speeds result in large forces acting on the components of the transport mechanism, for example centrifugal forces when the transport mechanism rotates. The larger the size of the sheets being processed, the more pronounced this effect becomes. Therefore, known systems involve stopping the transport mechanism for large sheet sizes and removing the waste sheets with additional moving elements. This limits the maximum processing speed and requires complex mechanisms.

[0006] WO 2017 / 153056 discloses an ejection member for on-the-fly waste removal in a sheet processing machine. The ejection member comprises a comb configured to switch between a first low speed position and a second high speed position. In the high speed position, the center of the comb is retracted to compensate for deformations of the sheets to be processed and of elements of the transport mechanism. However, the ejection member and a sheet processing machine having such a mechanism require a complex and costly design. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] International Publication No. 2017 / 153056 Summary of the Invention [Problem to be solved by the invention]

[0008] It is an object of the present invention to provide a simple mechanism for waste discharge in a sheet processing machine, which preferably allows high processing speeds even for large sheet sizes. [Means for solving the problem]

[0009] The object of the present invention is solved by a sheet processing machine having a transport mechanism for moving a sheet along a handling direction of the sheet processing machine and a waste ejection device for ejecting the sheet. The transport mechanism comprises a sheet handling element for moving the sheet, the sheet handling element comprising at least one sliding element. The sheet handling element is configured to eject the sheet when passing through the waste ejection device. The waste ejection device comprises at least one alignment element configured to interact with the at least one sliding element to minimize deformation of the sheet handling element when passing through the waste ejection device.

[0010] The invention is based on the idea of ​​providing a simple and inexpensive mechanical means of maintaining the shape of a sheet handling element as it passes through a waste ejection device. The sliding interaction between at least one sliding element of the transport mechanism and at least one alignment element of the waste ejection device can minimize wear on these components while allowing a reliable stabilization of the shape of the sheet handling element, so that high processing speeds of the sheet processing machine are possible.

[0011] By minimizing deformation of the sheet handling elements, the mechanical stresses on the sheet handling elements can be reduced, thereby minimizing the risk of damage and / or breakage of the sheet handling elements, particularly when using high processing speeds.

[0012] The at least one sliding element is preferably arranged at a leading edge of the sheet handling element. The term "leading edge" denotes a part of the sheet handling element that is arranged at the front of the sheet handling element relative to the processing direction of the sheets processed in the sheet processing machine. By providing the at least one sliding element at the leading edge, the at least one alignment element of the waste ejection device can interact with the sliding element before any other part of the sheet handling element comes into contact with the waste ejection device. This can simplify the shape and size of the alignment element and can minimize or even prevent deformation of the sheet handling element as soon as it comes into contact with the waste ejection device.

[0013] The leading edge in particular defines a length of the sheet handling element and the at least one sliding element is in particular arranged along the length between a first end and a second end of the sheet handling element, the second end being opposite the first end along the length, so that deformations along the leading edge of the sheet handling element in particular can be prevented or at least minimized.

[0014] The sheet handling element in particular has a length along its length of 106 cm or more, for example a length in the length direction of 140 cm to 170 cm.

[0015] The length of the sheet handling element along the longitudinal direction corresponds in particular to the size of the sheets to be processed by the sheet processing machine, so that the sheet processing machine according to the invention is in particular capable of processing large size sheets, since the sheet handling element can be stabilized by at least one registration element of the waste discharge device.

[0016] The sheet handling element may comprise a number of sliding elements, particularly arranged symmetrically around the centre of the length of at least one sheet handling element, in order to further minimise the extent of deformation of the sheet handling element or to prevent such deformation altogether.

[0017] In other words, the sliding elements are in particular arranged such that the sheet handling element has a mirror surface essentially longitudinally centred and longitudinally perpendicular with respect to the arrangement of the sliding elements.

[0018] In one variant, the sliding elements are arranged equidistant from one another along the length of the leading edge, which provides a particularly uniform distribution of positions at which at least one alignment element can interact with multiple sliding elements.

[0019] Preferably, the at least one sliding element is a roller. By using a roller as the sliding element, any force acting on the sliding element can be converted into a circular motion of the roller, so that the risk of the sliding element being damaged when interacting with the at least one alignment element is eliminated or at least minimized.

[0020] The sheet handling element may comprise at least one gripping element displaceable between a sheet gripping state and a sheet releasing state, the at least one gripping element being arranged at a trailing edge of the sheet handling element, the trailing edge being opposite the leading edge.

[0021] The at least one gripping element may serve to secure the sheet as it is moved by a transport mechanism along a handling direction through processing stations of a sheet processing machine.

[0022] Thus, the at least one sheet handling element may in particular be a gripping bar, preferably a gripping bar comprising a plurality of gripping elements.

[0023] The gripping elements, like the sliding elements, can be arranged symmetrically about the centre of the length of the at least one sheet handling element so as to grip the sheets in an evenly distributed manner.

[0024] The at least one gripping element does not interfere with the at least one sliding element by arranging the at least one gripping element on the opposite side of the sheet handling element to the at least one sliding element. Furthermore, the only contact between the sheet handling element and the sheet can be easily achieved by the at least one gripping element, i.e. the sheet does not have to come into contact with any other part of the sheet handling element.

[0025] At least one alignment element of the waste ejection device may comprise a sliding surface for interaction with the at least one sliding element, in other words the direction of movement of the at least one sliding element, and thus the sheet handling element, may be at least partly defined by the path of the sliding surface.

[0026] Preferably, the sliding surface has a curved shape.

[0027] For example, the sliding surface can be arranged to coincide with the direction of movement of the sheet handling elements when passing through the waste ejection station. This means that the transport mechanism can move substantially half way around the loop in which the sheet is moved along the processing direction by the sheet handling elements, and return to the starting position substantially the other half of the loop along the reverse direction without the sheet, to grip the next sheet to be processed. The sliding surface can be arranged at the turnaround point between the two halves of the loop in the waste ejection device.

[0028] Preferably, the waste ejection device comprises one alignment element for each sliding element of the sheet handling element, each alignment element being associated with one sliding element, such that each sliding element present on the sheet handling element can contribute to preventing or at least minimizing deformation of the sheet handling element when passing through the waste ejection device.

[0029] The at least one alignment element can be a cam. Cams are inexpensive and available in a variety of sizes and shapes to provide the desired interaction between the at least one sliding element and the cam. Additionally, the cam can be designed to minimize the space required.

[0030] The waste ejection device may further comprise a comb comprising a plurality of teeth, which is used to hold waste sheets fed to the waste ejection device by the transport mechanism while allowing the sheet handling elements to pass through. The teeth of the comb are therefore in particular arranged such that at least one gripping element of at least one sheet handling element can pass through the comb.

[0031] The waste ejection device may use a comb having a fixed shape by minimising deformation of the sheet handling elements.

[0032] Preferably, the transport mechanism moves the sheets from a loading station of the sheet processing machine to a waste discharge station of the sheet processing machine which is provided with a waste discharge device.

[0033] Preferably, the transport mechanism comprises a plurality of sheet handling elements, which allows for very high processing speeds of the sheet processing machine.

[0034] Further advantages and features of the present invention will become apparent from the following description of the invention and the accompanying drawings which show non-limiting exemplary embodiments of the invention. [Brief description of the drawings]

[0035] [Figure 1] 1 shows diagrammatically a sheet processing machine according to the invention; [Diagram 2] 2 shows a perspective view of a waste discharge device of the sheet processing machine of FIG. 1; [Diagram 3] 3 shows the waste ejection device of FIG. 2 when interacting with a sheet handling element. [Figure 4] 4 illustrates a traverse through the waste discharge device of FIG. 3; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0036] 1 shows diagrammatically a sheet processing machine 10 making it possible to cut blanks from a series of sheets 12. Usually these blanks are intended to be subsequently folded and glued to form packaging boxes. However, the sheets 12 can generally be made, for example, of paper, cardboard, foil, composites thereof or any other material routinely used in the packaging industry.

[0037] The sheet processing machine 10 comprises a series of processing stations juxtaposed but interdependent to form an integral assembly, including a loading station 14, then a cutting station 16 (also commonly referred to as a punching station) with, for example, a die or platen press 18, where the sheet 12 is transformed by cutting, a waste removal station 20 where the majority of the waste portion is peeled off, a blank separation station 22 (also commonly referred to as a receiving station) for separating blanks (or blanking step) by a blanking tool 23, and a waste discharge station 24 for removing the residual waste sheet of the punched sheet 12.

[0038] The number and nature of the processing stations may vary depending on the nature and complexity of the converting operation being performed on sheet 12 .

[0039] The sheet processing machine 10 further includes a transport mechanism 26, which in the illustrated embodiment is a conveyor for enabling each sheet 12 to be moved individually from the exit of the loading station 14 to the waste discharge station 24.

[0040] The conveyor employs a series of sheet handling elements 28 that are movably mounted by two loops of chain 30 disposed laterally on each side of the sheet processing machine 10. Each loop of chain 30 moves around a loop that enables the sheet handling elements 28 to follow a trajectory that passes successively through the cutting station 16, the waste removal station 20, the blank separation station 22 and the discharge station 24.

[0041] Each sheet handling element 28 travels on a forward path in the substantially horizontal plane of the path between the driven wheels 32 and the idler wheels 34 for substantially the first half of its path, and then travels on a return path in the upper portion of the sheet processing machine 10 for substantially the second half of its path. As each sheet handling element 28 returns to the driven wheels 32, it can then grip a new sheet 12 by its leading edge.

[0042] In the embodiment shown, the sheet handling element 28 is a so-called gripper bar.

[0043] In FIG. 1, each processing station is illustrated in the form of two rectangles symbolizing an upper and lower portion, respectively, positioned on either side of the plane of movement of sheet 12. As shown in FIG.

[0044] In FIG. 1, the transverse (or lateral), longitudinal and vertical directions are shown in an orthogonal spatial system (T, L, V).

[0045] The terms "upstream" and "downstream" are defined relative to the direction of movement of sheet 12 in the handling direction, as indicated by arrow D in FIG.

[0046] The waste discharge station 24 further comprises a waste discharge device 36 for discharging the sheets 12 that have been transferred from the loading station 14 to the waste discharge station 24, i.e., for removing the waste sheets.

[0047] FIG. 2 is a perspective view of the waste discharge device 36.

[0048] The waste ejection device 36 includes two alignment elements 38 , each of which is a cam with a curved sliding surface 40 .

[0049] The alignment element 38 is rigidly attached to the frame 41 by means of screws 42, ie the alignment element 38 is fixed in position.

[0050] The waste ejection device 36 further includes a comb 44 having a plurality of teeth 46 .

[0051] The comb 44 is formed from a first sheet 48 and a second sheet 50 joined by a number of fastening elements 52. The first sheet 48 is made from a plastic material that limits the noise of the sheet impacting on the comb 44, while the second sheet 50 is made from a metal that gives sufficient mechanical strength to the comb 44. Of course, alternatively, both the first sheet 48 and the second sheet 50 can be made from plastic or metal, as long as sufficient mechanical strength of the comb 44 is achieved.

[0052] 3 and 4 show the waste ejection device 36 as one of the sheet handling elements 28 passes through it.

[0053] The sheet handling elements 28 have two sliding elements 54, which in the illustrated embodiment are rollers. Each of the sheet handling elements 28 is associated with one of the alignment elements 38 of the waste ejection device 36.

[0054] More specifically, each of the sliding elements 54 is configured to roll along the sliding surface 40 of the associated alignment element 38 as the sheet handling element 28 passes through the waste ejection device 36 .

[0055] Of course, the sheet handling element 28 can in principle have only one or more than two sliding elements 54 .

[0056] The sliding element 54 is disposed at a leading edge 56 of the sheet handling element 28. The leading edge 56 defines a length of the sheet handling element 28, and the sliding element 54 is disposed at the leading edge 56 between a first end 58 and a second end 60 of the sheet handling element 28.

[0057] The length direction extends along the transverse direction T and defines the size of the sheet 12 along the transverse direction T that is manageable by the sheet processing machine 10 .

[0058] Opposite the leading edge 56 , the sheet handling element 28 is provided with a plurality of gripping elements 62 at a trailing edge 64 of the sheet handling element 28 .

[0059] The gripping element 62 is displaceable between a sheet gripping state and a sheet ejecting state, and switching between these two states is achieved at the waste ejection station 24 by interaction of an opening mechanism 66 of the sheet handling element 28 with an opening cam (not shown) of the waste ejection device 36.

[0060] Each of the gripping elements 62 comprises two arms 63 which are pressed against one another in the gripping state, for example by a force exerted by a spring mechanism (not shown) of the sheet handling element 28. In the sheet-releasing state, the arms 63 of the gripping elements 62 are separated from one another to allow the sheet 12 to be placed between the arms 63. When displaced back to the gripping state, the sheet 12 is accordingly pressed and fixed between the arms 63.

[0061] Both the sliding element 54 and the gripping element 62 are symmetrically disposed about the longitudinal center of the leading edge 56 and trailing edge 64, respectively.

[0062] The mode of operation of the waste discharge device 36 will now be described in more detail.

[0063] The gripping elements 62 of the sheet handling elements 28 are used to grip the leading edge of the sheet 12 at the exit of the loading station 14 during operation of the sheet processing machine 10, ie the gripping elements 62 are in a gripping state (see FIG. 1).

[0064] The sheet 12 is then moved by movement of the sheet handling element 28 along the handling direction D through the processing station, resulting in the waste sheet being grasped by the gripping element 62 when the sheet handling element 28 reaches the waste discharge station 24 having the waste discharge device 36.

[0065] As mentioned above, the chain 30 of the transport mechanism 26 defines a forward and a return path. The transition between the forward and return paths is defined by passing through a turn point defined by an idler wheel 34 at a waste discharge device 36.

[0066] Thus, the sheet handling element 28 is drawn along the turning point by the movement of the chain 30 .

[0067] Due to the high processing speed of the sheet processing machine 10, this leads to centrifugal forces acting on the sheet handling elements 28. The centrifugal forces will result in deformation of the sheet handling elements 28. In particular, the sheet handling elements 28 will become bowed when deformed, i.e., they will no longer be straight along their length.

[0068] However, the sliding elements 54 of the sheet handling element 28 contact the associated curved sliding surfaces 40 as the sheet handling element 28 passes through the waste discharge device 36, thereby preventing or at least minimizing deformation of the sheet handling element 28 as it passes through the waste discharge device 36.

[0069] In other words, the interaction of the sliding element 54 of the sheet handling element 28 with the alignment element 38 acts like a rigid member for the sheet handling element 28, ensuring that the sheet handling element 28 remains essentially straight along its length as it passes through the waste ejection device 36.

[0070] The gripping elements 62 at the trailing edges 64 pass between the teeth 46 of the comb 44 as the sheet handling element 28 passes through the waste ejection device 36 .

[0071] Thus, a sheet 12 held by the gripping elements 62 , or more precisely a waste sheet, will collide with the teeth 46 as the trailing edge 64 passes through the comb 44 .

[0072] At the same time, the gripping elements 62 are displaced to a sheet-ejecting state by interaction of an opening cam (not shown) of the waste ejection device 36 with an opening mechanism 66 .

[0073] Thus, when the sheet 12 impacts the comb 44 it is retained but the sheet handling element 28 is able to pass through the waste ejection device 36. The retained sheet 12, which is waste, can be collected and disposed of at the waste ejection station 24.

[0074] The sheet processing machine according to the invention makes it possible in a simple and inexpensive way to prevent or at least minimize deformations occurring in the sheet handling elements 28. This allows the sheet processing machine 10 to discharge waste sheets dynamically, i.e. without stopping the transport mechanism 26, even in the case of relatively large sheets 12. Furthermore, no moving elements are required in the waste ejection device 36 for removing the waste sheets.

Claims

1. A sheet processing machine (10) comprising: a transport mechanism (26) for moving a sheet (12) along a handling direction of the sheet processing machine (10); and a waste discharge device (36) for discharging the sheet (12), The transport mechanism (26) comprises a sheet handling element (28) for moving the sheet (12), the sheet handling element (28) comprising at least one sliding element (54); the at least one sheet handling element (28) is configured to eject the sheet (12) as it passes through the waste ejection device (36); the waste ejection device (36) comprises at least one alignment element (38) having a sliding surface (40) configured to interact with the at least one sliding element (54) to minimize deformation of the at least one sheet handling element (28) as it passes through the waste ejection device (36); A sheet processing machine characterized by:

2. the at least one sliding element (54) is arranged at a leading edge (56) of the sheet handling element (28); 2. The sheet processing machine according to claim 1.

3. the leading edge (56) defines a length of the sheet handling element (28), the at least one sliding element (54) being disposed along the length between a first end (58) and a second end (60) of the sheet handling element (28), the second end (60) being opposite the first end (58) along the length; 3. The sheet processing machine according to claim 2.

4. the at least one sheet handling element (28) comprises a plurality of sliding elements (54), the sliding elements (54) being in particular arranged symmetrically about a center of the length of the at least one sheet handling element (28); 4. The sheet processing machine according to claim 2 or 3.

5. The sliding elements (54) are equidistant from one another along the length of the leading edge (56).

5. The sheet processing machine according to claim 4.

6. said at least one sliding element (54) being a roller; 6. A sheet processing machine according to claim 1.

7. the at least one sheet handling element (28) comprises at least one gripping element (62) displaceable between a sheet gripping state and a sheet releasing state, the at least one gripping element (62) being arranged in particular at a trailing edge (64) of the at least one sheet handling element (28), the trailing edge (64) being opposite the leading edge (56); 6. A sheet processing machine according to claim 2.

8. The sliding surface (40) has a curved shape.

8. A sheet processing machine according to any one of claims 1 to 7.

9. the waste ejection device (36) comprises one alignment element (38) for each of the sliding elements (54) of the at least one sheet handling element (28), each of the alignment elements (38) being associated with one sliding element (54); 9. A sheet processing machine according to any one of claims 1 to 8.

10. The at least one alignment element (38) is a cam.

10. A sheet processing machine according to any one of claims 1 to 9.

11. The waste ejection device (36) further comprises a comb (44) including a plurality of teeth (46). A sheet processing machine according to any one of the preceding claims.

12. the transport mechanism (26) moves the sheet (12) from a loading station (14) of the sheet processing machine (10) to a waste discharge station (24) of the sheet processing machine (10) having the waste discharge device (36); A sheet processing machine according to any one of the preceding claims.

13. The transport mechanism (26) comprises a plurality of sheet handling elements (28); A sheet processing machine according to any one of the preceding claims.

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