METHOD AND DEVICE FOR CORRECTING THE POSITION OF A FOLDED BLANK IN A FOLDER-GLUER

Abstract

A method for checking and correcting the position of a blank comprised of three flaps arranged in a row, the method including the following steps: closing the right- and left-hand flaps one above the other at least in an overlapping portion, gluing the flaps together; positional checking of the right-hand edge and the left-hand edge and comparing those edges with a predetermined position in order to determine a positional deviation of the flaps and, if the positional deviation exceeds an admissible deviation value, then before the glue sets, fixing the central flap at a location via the lower face of central flap using a fixing device using vacuum-induced negative pressing, then holding the upper face of the right-hand flap and of the left-hand flap by respectively at least one suction cup which applies vacuum, and correcting the position of the left-hand flap and/or of the right-hand flap by moving the suction cups sideways.

Claims

1. A method for processing a blank designed to form, after folding-gluing, a folded flattened box, the method including the following steps: a) providing a substantially flat blank having a right-hand edge, a left-hand edge, a front edge, a rear edge, a right-hand longitudinal crease spaced from the right-hand edge and a left-hand longitudinal crease spaced from the left-hand edge, the right-hand longitudinal crease and the left-hand longitudinal crease, along with the right-hand edge and the left-hand edge, delimiting at least three flaps in a row comprised of a right-hand flap, a central flap and a left-hand flap; b) applying glue to a zone of the right-hand flap adjacent to the right-hand edge and/or applying glue to a zone of the left-hand flap adjacent to the left-hand edge, such that the glue is present in between overlapping portions that will be overlapping between the right-hand flap and the left-hand flap; c) folding the right-hand flap 180° about the right-hand longitudinal crease towards the central flap, and folding the left-hand flap 180° about the left-hand longitudinal crease towards the central flap; d) closing the folded right-hand flap and the folded left-hand flap to be positioned one above the other at least in the overlapping portion; e) positional checking of the right-hand edge and of the left-hand edge and comparing actual positions of the edges with a predetermined position in order to determine a positional deviation of the actual position from the predetermined position; f) if the positional deviation exceeds an admissible deviation value, applying the following sub-steps before setting of the glue in the between portions: f1) fixing the central flap against undesired movement via the lower face of the central flap by using a fixing device which uses vacuum-induced negative pressing of the lower face, then f2) holding the upper faces of the folded right-hand flap and of the folded left-hand flap; and f3) correcting the position of at least one of the left-hand flap and the right-hand flap; g) applying pressure between the right-hand flap and the left-hand flap in the overlapping portion until the glue sets; and h) releasing of the central flap, of the right-hand flap and of the left-hand flap.

2. A method according to claim 1, further comprising holding the upper face of the folded right-hand flap and the upper face of the folded left-hand flap during step f2) by using at least one suction cup with vacuum to press at least one of the left-hand flap and the right-hand flap, and the correction of the position of at least one of the left-hand flap and the right-hand flap during step f3) is implemented by moving the suction cup while it is with vacuum.

3. A method according to claim 2, wherein if the positional deviation detected is a distance that is between the right-hand edge and the left-hand edge and that falls outside the admissible range, implementing step f2), for each of the right-hand flap and the left-hand flap, using two suction cups that are offset longitudinally on each of the right-hand flap and the left-hand flap and that are vacuumized during the holding, and step f3) is implemented with sideways movement of at least the two suction cups of at least one of the right-hand flap and the left-hand flap, to adjust the distance between the right-hand edge and the left-hand edge to bring the left-hand edge and the right-hand edge within the admissible range.

4. A method according to claim 2, wherein if the positional deviation detected is a non-paralleling fault between the right-hand edge and the left-hand edge, step f2) is implemented, for both of the right-hand flap and the left-hand flap, using a single suction cup which is vacuumized during holding, and step f3) is implemented by using sideways movement of the suction cup for moving the right-hand flap and/or the left-hand flap, in order to adjust the orientation of at least one of the right-hand flap and the left-hand flap and to bring the right-hand edge and the left-hand edge substantially parallel to one another.

5. A device for correcting the position of a blank in a folder-gluer, for a substantially flat blank having a right-hand edge, a left-hand edge, a front edge, a rear edge, a right-hand longitudinal crease and a left-hand longitudinal crease, the right-hand longitudinal crease and the left-hand longitudinal crease delimiting, with the right-hand edge and the left-hand edge, at least three flaps in a row including a right-hand flap, a central flap and a left-hand flap; the device comprising: a device configured and operable for folding the right-hand flap and the left-hand flap over the central flap; a device for checking the relative positions between the right-hand edge and the left-hand edge in the transverse left-right direction after folding the right-hand flap and the left-hand flap; a vacuum applying device located and configured for fixing the central flap and that is configured to apply vacuum-induced negative pressure to a lower face of the central flap of the blank; a glue applicator configured to apply glue to one of a zone of the right-hand flap adjacent to the right-hand edge and a zone of the left-hand flap adjacent to the left-hand edge, such that the glue is present in an overlapping portion between the right-hand flap and the left-hand flap; a correction device configured for correcting the position of at least one of the left-hand flap and the right-hand flap; and a presser device configured to create a pressing contact between the right-hand flap and the left-hand flap in the overlapping portion.

6. A device according to claim 5, further comprising the correction device includes at least one first suction cup located and configured to hold the right-hand flap and at least one second suction cup located and configured to hold the left-hand flap, the first and second suction cups are oriented downwards toward their respective right-hand flap and left-hand flap and are movable vertically and transversely, and are configured to be vacuumized.

7. A device according to claim 6, in which the correction device includes a pair of first and second right-hand suction cups and a pair of first and second left-hand suction cups.

8. A device according to claim 7, further comprising for each pair of right-hand suction cups and left-hand suction cups, a first suction cup is positioned toward the front and a second suction cup is positioned toward the rear of the respective flaps, wherein the vacuumization of the first suction cup is controlled independently from the vacuumization of the second suction cup.

9. A device according to claim 7, further comprising a right-hand supporting element supporting the two suction cups in the pair of right-hand suction cups making it possible to simultaneously move both of the right-hand suction cups, and a left-hand supporting element supporting the two suction cups in the pair of left-hand suction cups making it possible to simultaneously move both left-hand suction cups.

10. A device according claim 5, further comprising an element inserted between the right-hand flap and the left-hand flap before folding the flaps, and the element is withdrawn following the correction by the correction device.

11. A device according to claim 5, wherein the control device includes optical detection.

12. A device according to claim 11, wherein the fixing device includes at least one boom fitted with nozzles that are oriented upwards and that are configured to create a vacuum.

13. A device according to claim 12, wherein the boom is assembled on a linear motor accompanying the blank along travel of the blank, and in which the vacuum of the nozzles is activated if a correction is to be made.

14. A device according to claim 5, wherein the correction device and the fixing device are also configured to advance in the longitudinal direction at the same speed as the blank during the longitudinal travel of boom.

15. A folder-gluer machine fitted with a correction device according to claim 5.

Description

SHORT DESCRIPTION OF THE FIGURES

[0037] Example embodiments of the invention are given in the description, which is illustrated by the attached figures, in which:

[0038] FIG. 1 is a projection of a cardboard blank,

[0039] FIGS. 2 and 3 show this cardboard blank after the lateral flaps have been folded, respectively from above and from the front in the direction III shown in FIG. 2,

[0040] FIGS. 4, 5 and 6 are similar to FIG. 2 and show arrangements with different folding anomalies,

[0041] FIGS. 7, 8 and 9 show the correction method according to the invention, respectively for the folding anomalies in FIGS. 4, 5 and 6,

[0042] FIGS. 10A and 10B show, respectively for a first position and for a second position, a bottom view of an embodiment of a correction device,

[0043] FIGS. 11A and 11B show, respectively for the first position and for the second position, a partial side view of the embodiment of the correction device, respectively in the direction XIA in FIG. 10A and in the direction XB in FIG. 10B,

[0044] FIG. 12 shows a view in the direction XII in FIG. 11, showing the upper part of the correction device in FIG. 10 from below,

[0045] FIG. 13 is a partial side view of the embodiment of the correction device according to the present invention,

[0046] FIG. 14 shows a view in the direction XIV in FIG. 13, showing a portion of the lower part of the correction device in FIG. 13 from above,

[0047] FIG. 15 is a cross-sectional view in the direction XV-XV in FIG. 14,

[0048] FIGS. 16A and 16B show, respectively for the first position and for the second position, a top view in the direction XVI in FIG. 13, showing from above another portion according to the present invention of the lower portion of the correction device in FIG. 13, and

[0049] FIGS. 17A and 17B show, respectively for the first position and for the second position, a side view in the direction XVII in FIG. 13, showing from the side the lower portion of the correction device in FIG. 13.

EXAMPLE EMBODIMENTS OF THE INVENTION

[0050] FIG. 7 shows the principle of the method for correcting an excessively large gap, specifically G′-Gréf>0. Consequently, in this case and following 180° folding of the right-hand flap 17 and of the left-hand flap 18, if a positional deviation is detected, i.e. the distance between the right-hand edge and the left-hand edge or the gap is outside the admissible range, as for the gap G′ in FIG. 4 or FIG. 7, the following procedure is followed. Following fixing of the central flap 19, the upper face of the folded right-hand flap 17 and the upper face of the folded left-hand flap 18 are held simultaneously and respectively by two suction cups 21, 23 offset in a longitudinal direction and by two suction cups 24, 26 offset in the longitudinal direction.

[0051] For this purpose, the four suction cups 21, 23, 24 and 26 are lowered until they come into contact with the upward oriented face of the folded right-hand flap 17 and with the upward oriented face of the folded left-hand flap 18. The four suction cups 21, 23, 24 and 26 are vacuumized and securely hold the right-hand flap 17 at two points and the left-hand flap 18 at two points. Subsequently, as a function of the value of the lateral positional deviation (G′-Gréf) between the right-hand edge 13 and the left-hand edge 14, and any need to center this gap on a longitudinal midline of the blank (superposed on the axis X-X′), as identified by a positional check of the right-hand and left-hand edges 13, 14, the right-hand flap 17 or the left-hand flap 18 or both the right-hand flap 17 and the left-hand flap 18 are moved by moving some or all of the suction cups 21, 23, 24 and 26.

[0052] To do so, the position of the left-hand flap 18 and/or of the right-hand flap 16 is corrected by the sideways movement of the two suction cups 21, 23 of the right-hand flap 16 and/or of the two suction cups 24, 26 of the left-hand flap 18, in order to adjust the distance between the right-hand edge 13 and the left-hand edge 14 to bring same within the admissible range.

[0053] In a preferred embodiment, the two right-hand suction cups 21 and 23, including the front right-hand suction cup 21 and the rear right-hand suction cup 23, are moved jointly. Thus, in FIG. 7, to move the right-hand edge 13 towards the axis X-X′, the pair of right-hand suction cups 21, 23 is moved towards the left. Equally and preferably, the two left-hand suction cups 24 and 26, including the front left-hand suction cup 24 and the rear left-hand suction cup 26, are moved jointly. Thus, in FIG. 7, to move the left-hand edge 14 towards the axis X-X′, the pair of left-hand suction cups 24, 26 is moved towards the left.

[0054] FIGS. 8 and 9 show respectively the principle of the method for correcting rear fishtailing or front fishtailing. Thus, in this case and following 180° folding of the right-hand flap 17 and of the left-hand flap 18, if a positional deviation is detected in the form of a paralleling fault between the right-hand edge 13 and the left-hand edge 14, with an angular value α1 or α2 exceeding a maximum admissible value, this folding does not fall within the permissible range and, as for FIGS. 5 and 6, the following procedure is followed.

[0055] Following fixing of the central flap 19, the following is carried out simultaneously:

[0056] holding the upper face of the folded right-hand flap 17 by a single front or rear right-hand suction cup 21, 23 (the front right-hand suction cup 21 in FIGS. 8 and 9 in which the rear right-hand suction cup 23 is represented using a dotted line since it is not vacuumized and is therefore not holding the back of the right-hand flap 17), and

[0057] holding the upper face of the folded left-hand flap 18 by a single front or rear left-hand suction cup 24, 28 (the front left-hand suction cup 24 in FIGS. 8 and 9 in which the rear left-hand suction cup 26 is represented using a dotted line since it is not vacuumized and is therefore not holding the back of the right-hand flap 17).

[0058] For this purpose, the four suction cups 21, 23, 24 and 26 are lowered in right- or left-hand pairs until they come into contact with the upward oriented face of the folded right-hand flap 17 and with the upward oriented face of the folded left-hand flap 18. In the example illustrated, only the front suction cup 21 and 21 of each pair is vacuumized. Consequently, holding results in the right-hand flap 17 being held securely at a single point (in this case at the front) and the left-hand flap 18 being held securely at a single point (in this case at the front). Subsequently, as a function of the value of the lateral positional deviation between the right-hand edge 13 and the left-hand edge 14 (identified in this case as G1-Gréf at the front and G2-GRéf at the rear, with the angle α1 or α2 measured between the right-hand edge 13 and the left-hand edge 14 possibly being taken into account), and any need to center this gap on a longitudinal midline of the blank (superposed on the axis X-X′), as identified by a positional check of the right-hand and left-hand edges 13, 14, the right-hand flap 17 or the left-hand flap 18 or both the right-hand flap 17 and the left-hand flap 18 simultaneously are moved by moving one or both of the front suction cups 21 and/or 24 sideways. Alternatively, in a correction method not shown, this angular movement is obtained by moving one or both of the rear suction cups 23 and/or 26 sideways.

[0059] Thus, in FIG. 8, the rear fishtailing is corrected by a sideways movement of the front suction cups 21 and 24 towards the external lateral sides of the folded blank 10, which are located on the same flap as the suction cup. Consequently, as shown in FIG. 8, the front right-hand suction cup 21 is moved towards the right-hand side 15′, i.e. towards the right, and the front left-hand suction cup 24 is moved towards the left-hand side 16′, i.e. towards the left.

[0060] In FIG. 9, the front fishtailing is corrected by a sideways movement of the front suction cups 21 and 24 towards the external lateral sides of the folded blank 10, which are located on the flap that is not the flap with the related suction cup. Consequently, as shown in FIG. 9, the front right-hand suction cup 21 is moved towards the left-hand side 16′, i.e. towards the left, and the front left-hand suction cup 24 is moved towards the right-hand side 15′, i.e. towards the right.

[0061] Consequently, if the positional deviation detected is a paralleling fault between the right-hand edge 13 and the left-hand edge 14, the angular position of the left-hand flap 18 and/or of the right-hand flap 16 is corrected using, for the right-hand flap 16 and for the left-hand flap 18, a single suction cup that is vacuumized to hold the corresponding flap, and which remains vacuumized during the sideways movement of same, as a result of which the orientation of the right-hand flap 17 and/or of the left-hand flap 18 is altered to bring the right-hand edge 13 and the left-hand edge 14 substantially parallel to one another.

[0062] This action to change the angular position of the right-hand flap 17 or of the left-hand flap 18 or of the right-hand flap 17 and of the left-hand flap 18 simultaneously also works through the partial vacuumizing and sideways movement of one or other of the front suction cup 21 (24) and the rear suction cup 23 (26): this holding at a single point of the flap in question makes it possible to adjust the angle formed between the edge of this flap and the axis X-X′ provided that this holding point of the flap by the suction cup is not positioned at the middle of the length (along the axis X-X′ of the folder-gluer).

[0063] In this case, not shown, where the folded blank 10 has both an inadmissible gap and an inadmissible paralleling fault, the invention enables both anomalies to be addressed and corrected. In practice, the gap is corrected first through the sideways movement of the two suction cups in each pair (right and left), the four suction cups 21, 23, 24 and 26 being engaged with the right- and left-hand flaps 17, 18, as explained above with reference to FIG. 7. Aspiration of one of the two suction cups in each pair is then stopped to correct the fishtailing, as set out above in relation to FIGS. 8 and 9.

[0064] FIGS. 10 to 13 show the upper part of the correction device. Again in this case, the correction means include at least one suction cup designed to hold the right-hand flap 17 and at least one suction cup designed to hold the left-hand flap 18, the suction cups being oriented downwards, movable vertically and transversely, and able to be vacuumized. In particular, the correction means include a pair of right-hand suction cups 21, 23 and a pair of left-hand suction cups 24, 26.

[0065] Equally, for each pair of suction cups, a first suction cup 21 (24) is located at the front and a second suction cup 23 (26) is located at the rear. Furthermore, the vacuumization of the first suction cup 21 (24) is controlled independently from the vacuumization of the second suction cup 23 (26).

[0066] To facilitate assembly and control, the two suction cups 21, 23 in the pair of right-hand suction cups are assembled on a right-hand supporting element 31 making it possible to simultaneously move both suction cups 21, 23, and both suction cups 24, 26 in the pair of left-hand suction cups are assembled on a left-hand supporting element 32 making it possible to simultaneously move both suction cups 24, 26. In particular, in order to ensure the correction as described above, the simultaneous movement of the two suction cups in each pair is done in a transverse direction (orthogonal to the direction of forward movement A) and vertically.

[0067] Furthermore, as shown in FIGS. 10 and 11, in order to follow the travel of the blank 10 in the direction of forward movement A while the correction is being made by the suction cups 21, 23, 24, 26, the right-hand supporting element 31 (left-hand supporting element 32) is assembled using a right-hand bracket 33 (left-hand bracket 34) on the rod 35 (36) of a right-hand linear motor 37 (left-hand linear motor 38). Thus, FIGS. 10A and 11A show a first position corresponding to the idle position awaiting the arrival of a new blank, and FIGS. 10B and 11B show a second position corresponding to the end-of-travel position when the blank has been folded, glued and possibly corrected.

[0068] FIGS. 10 and 11 also show the compression module 40 feeding air in a partial vacuum to the right-hand suction cups 21, 23 via a right-hand pipe 41 and feeding air in a partial vacuum to the left-hand suction cups 24, 26 via a left-hand pipe 42.

[0069] Optical detection means (not shown) are preferably used to check the position of the right-hand edge 13 and of the left-hand edge 14 after folding of the right-hand flap 17 and of the left-hand flap 18. For example, optical detection as described in document EP 0937573 is used.

[0070] These detection means measure the gap between the right-hand edge 13 and the left-hand edge 14 after folding of the right-hand flap 17 and of the left-hand flap 18, at several positions along the longitudinal direction. In this way, calculation means are used to compare each of these measured values with the reference gap, with a predetermined value Gréf, and the need for a correction is determined. In this case, the correction required to bring the blank within the admissible deviation range is calculated.

[0071] Numerous different cases are possible, such as a correction of the left-hand flap 18 only, of the right-hand flap 17 only, of the left-hand flap 18 and the right-hand flap 17 simultaneously, and, for the flap or flaps, using both suction cups in the pair (right or left) in question (gap only), a single suction cup in the pair (right or left) in question (fishtailing only), both suction cups and then a single suction cup in the pair (right or left) in question (gap and fishtailing).

[0072] By way of example, the right-hand supporting element 31 and the left-hand supporting element 32 have a longitudinal travel (along the axis X-X′ of the folder-gluey) of 200 mm thanks to the linear motors 37 and 38. This longitudinal travel makes it possible to follow the blank 10 during a portion of the forward movement of same while performing the correction during the forward movement in the direction of forward movement A. Also by way of example, the right-hand supporting element 31 and the left-hand supporting element 32 have a transverse travel (in the direction orthogonal to the axis X-X′ of the folder-gluer) of between 10 mm and 30 mm. This transverse travel is sufficient to correct the anomalies found in most cases relating to blanks of maximum size, for example 1100 mm by 1700 mm. Pressing means used to create a pressing contact between the right-hand flap 17 and the left-hand flap 18 in the overlapping portion.

[0073] FIGS. 11A, 11B, 13, 14, 15, 16A, 16B, 17A and 17B relate to the lower portion of the correction device which completes the elements used to enable the forward movement of the blank in the longitudinal direction using means for fixing the central flap 19. The elements enabling the forward movement of the blank 10 are endless belts 60, three of which can be seen in FIGS. 16A, 16B, 17A and 17B, arranged in parallel with one another beneath the suction cups 21, 23, 24, 26. These fixing means are intended to hold the blank 10 at the central flap 19 of same, preventing same from rising or in particular moving laterally. If the blank were not held by the central flap 19 of same, the position of the right-hand flap 17 and/or of the left-hand flap 18 could not be corrected efficiently and precisely.

[0074] One embodiment of these means 70 for fixing the central flap 19 uses (see FIGS. 13 to 17), as means for gripping the central flap 19, vacuum-induced negative pressing of the lower face of the central flap 19. Thus, the partial air vacuumization enables the central flap 19 to be held from below by aspiration as long as the vacuum is maintained. More specifically, the fixing means 70 include at least one boom 71 fitted with nozzles 72 oriented upwards that are able to create a vacuum. These nozzles 72 output onto a supporting plate 75 on which the blank 10 rests, while being driven by the belts 60. In the case shown, two booms 71 are arranged along either one of the external belts 60. For this purpose, the nozzles 72 act as suction cups by suctioning the lower face of the central flap 19 downwards when they are fed with air in a partial vacuum. To do so, a pressing module 73 provides the booms 71 with air in a partial vacuum via the pipes 74.

[0075] The boom 71 is assembled (see FIGS. 13 to 17) on a linear motor 80 accompanying the blank 10 along the travel of same in the longitudinal direction of the folder-gluer machine. Thus, to grip the central flap 19 via the lower face of same and to fix same vertically and also transversely in relation to the folder-gluer, the vacuum in the booms 71 is activated, as a result of which each nozzle 72 engages a surface of the lower face of the central flap 19, thereby enabling correction of the right-hand flap 17 and/or of the left-hand flap 18.

[0076] For easy and quick starting, the linear motor 80 is placed along the conveyance means that move the blank forwards in the longitudinal direction of the folder-gluer. In the embodiment illustrated, as shown in FIGS. 16A and 16B, these conveyance means are endless belts 60. Advantageously, three endless belts 60 are arranged across the width of the module of the folder-gluer and a boom 71 is assembled alongside and outside the two outside belts. In a variant not shown, a boom 71 is assembled between each pair of belts 60. As such, the blanks 10 are driven by the belts 60 and pressed downwards when the booms 71 are vacuumized.

[0077] The linear motors 80 accompany the longitudinal travel of the blank 10 in all cases, regardless of whether a correction is performed. Furthermore, the linear motors 80 are retracted and returned to their initial position soon after the blank 10 leaves the correction device and before arrival of the following blank 10 in the correction device.

[0078] Advantageously, the correction means (suction cups 21, 23, 24, 26) and the fixing means (booms 71) can move in the longitudinal direction (X-X′) of the folder-gluer machine at the same speed as the blank 10 during the longitudinal travel of same. In practice, the motor controlling the longitudinal travel of the right-hand supporting element 31 and of the left-hand supporting element 32 is synchronized with the motor controlling the linear motors 80 bearing the suction nozzles 71.

[0079] Preferably, gluing is performed before folding of the right-hand flap 17 and of the left-hand flap 18. It is nonetheless essential that the glue is prevented from setting in the overlapping portion between the right-hand flap 17 and the front left-hand flap 18 before and during the positional check (i.e. during steps d), e)) and during any positional correction performed (step f)). For this purpose, according to an advantageous arrangement illustrated partially in FIG. 13, the right-hand flap is prevented from touching the left-hand flap by an element 90 inserted between the right-hand flap 17 and the left-hand flap 18, and before step g) the element 90 is removed and pressing contact is made between the glue, the right-hand flap 17 and the left-hand flap 18 in the overlapping portion, preferably until the glue sets.

[0080] In the machine, the correction device therefore preferably also includes an element 90 that can be inserted between the right-hand flap and the left-hand flap before same is folded, and that can be removed before the correction. FIG. 13 partially shows this element 90, which may be in the form of a rod attached by the rear end of same from the top, enabling the blank to pass just beneath the element 90. In this embodiment, the folding and correction of the blank are carried out as the blank 10 is moving forwards. When folding the right-hand flap 17 and the left-hand flap 18, and during the positional check and any correction made, the right-hand flap 17 and the left-hand flap 18 are above the rod, which is in turn above the central flap 19. Following correction, and while the pressure rollers are bearing downwards, the more advanced position of the blank 10 releases the rod, which comes away from the blank, as a result of which the contact between the right-hand flap 17, the left-hand flap 18 and the central flap 19 is ensured to enable the glue to set.

[0081] In another embodiment, this element 90 is not used, in which case the position of the right-hand flap 18 and of the left-hand flap 17 in relation to the central flap 19 is corrected quickly enough to enable this correction to be made before the glue sets.

[0082] The present invention is not limited to the embodiments described and illustrated. Numerous modifications can be made without thereby moving outside the scope of the claims. A folder-gluer may also be a folder-gluer unit, assembled for example in an on-line machine, downstream of a flexo press and of a rotary die-cutter. The linear motors 37, 38 and 80 may be replaced by jacks.