Device for processing a plate element, processing unit and packaging production machine

Abstract

A device for processing a plate element (35) has a rotable hub (52), two tools (57, 58), mounted on the hub (52) to process the element (35) when each tool is in a respective processing position; a drive to rotate the hub (52) and the two tools (57, 58); a rotatable counter-tool (64). The rotation (R) of the hub (52) varies during a rotation cycle of the hub (52), and includes two constant speed phases during each of which one of the two tools (57, 58) is, in succession, in the processing position; and at least one phase with each of the two tools (57, 58) in an intermediate position between the respective processing positions, so as to achieve a front lateral processing position and a rear lateral processing position on the element (35).

Claims

1. A method of processing a plate element by a processing device mounted on a lateral side of a packaging production machine, the packaging production machine feeding the plate element in a longitudinal direction at an operating speed, the processing device comprising: a hub supported and configured to rotate about a substantially horizontal first rotation axis transverse to the longitudinal direction; two tools mounted on the hub spaced apart around the first rotation axis, a first tool of the two tools configured to process the plate element at a first processing position of the first tool, and a second tool of the two tools being configured to process the plate element at a second processing position of the second tool, the first tool being configured to process the plate element at a front lateral processing position on the plate element, and the second tool being configured to process the plate element at a rear lateral processing position on the plate element, wherein the front lateral processing position and the rear lateral processing position are along a lateral edge of the plate element; a hub drive configured to drive the hub and the two tools in rotation around the first rotation axis; a counter-tool supported and configured to rotate about a second rotation axis that is substantially horizontal, transverse to the longitudinal direction, and parallel to the first rotation axis of the hub, the plate element being engaged successively between the first tool and the counter-tool and between the second tool and the counter-tool; and the hub drive being configured and operable to drive the hub at a speed of rotation that varies during a rotation cycle of the hub, wherein the method comprises: operating the processing device; controlling the hub drive to implement a first phase and a second phase of the rotation cycle, during an entirety of the first and second phases, the hub being driven at a constant speed substantially equal to the operating speed, such that in the first phase the first tool is in the first processing position for processing the front lateral processing position on the plate element and in the second phase the second tool is in the second processing position for then processing the rear lateral processing position on the plate element; and controlling the hub drive to implement at least one third phase of the rotation cycle, the at least one third phase occurring after the first phase and before the second phase, and during the at least one third phase, driving the hub at a non-zero rotation speed that is different from the constant hub rotation speed and is set according to a distance on the plate element between the front lateral processing position and the rear lateral processing position, wherein during the at least one third phase, each of the two tools is moved through a respective intermediate position, in order to reach the corresponding first processing position and the second processing position for processing the plate element at, respectively, the front lateral processing position and the rear lateral processing position; and operating the counter-tool to have a speed of rotation throughout the at least one third phase that is substantially equal to the operating speed.

2. The method according to claim 1, wherein the at least one third phase includes, in succession, a phase of acceleration and a phase of deceleration.

3. The method according to claim 2, wherein the at least one third phase includes an intermediate phase at the constant speed.

4. The method according to claim 1, wherein the at least one third phase includes, in succession, a deceleration phase and an acceleration phase.

5. The method according to claim 1, wherein the at least one third phase includes, in succession, a deceleration phase, a stop phase and an acceleration phase.

6. The method according to claim 1, wherein during the second phase the second tool is located in the rear lateral processing position in the rotation cycle of the hub, and wherein during the first phase the first tool is located in the front lateral processing position, of a subsequent rotation cycle of the hub following the rotation cycle.

7. The method according to claim 1, wherein the hub is supported in a cantilevered manner.

8. The method according to claim 1, wherein the two tools are positioned radially at an angle relative to each other, the angle being smaller than 180°.

9. The method according to claim 8, wherein the angle is substantially equal to 100°.

10. The method according to claim 1, wherein a respective arm for each tool is securely fastened on the hub and positioned and configured to rotate with the hub; and each tool is mounted on an end of the respective arm.

11. The method according to claim 10, wherein each of the two arms is extended diametrically by an arm forming a counterweight.

12. The method according to claim 1, wherein the counter-tool comprises a cylinder coated with a coating made of a material having a softness such that the two tools penetrate the coating therein.

13. The method according to claim 12, wherein the coating comprises a layer of polyurethane.

14. The method according to claim 1, wherein the processing device is mounted in a creasing section of the packaging production machine.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The invention will be better understood and its various advantages and features will become more apparent from the following description of a non-limiting exemplary embodiment given with reference to the schematic drawings appended, in which:

(2) FIG. 1 shows a top view of a blank produced by a packaging production machine;

(3) FIG. 2 shows a side view of a processing unit comprising a device according to the invention;

(4) FIGS. 3 to 8 show partial side views showing the various positions adopted by the device during a rotation cycle;

(5) FIGS. 9 to 14 show various graphs of the device speed during the rotation cycle; and

(6) FIG. 15 illustrates a packaging production machine.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

(7) A cardboard blank 1, such as that illustrated in FIG. 1, is intended to form a case. Before folding, the blank 1 is formed by four adjacent portions 2, 3, 4 and 5, extending between two opposite lateral edges that lie parallel to the run direction (arrow T in FIGS. 1 to 8) of the blank 1 in the machine. The blank 1 is folded so that the distal end portion 2 and the proximal end portion 5 adjacent two opposite edges of the blank 1 are placed on the two central portions 3 and 4.

(8) Four parallel longitudinal creases 6, extending longitudinally to the run direction T of the blank 1, and two parallel front 8 and rear 7 transverse creases, extending transversely to the run direction T of the blank 1, divide each portion 2, 3, 4 and 5 into panels 9, 11, 12 and 13, respectively.

(9) The four panels 9, 11, 12 and 13 are intended to form the four sidewalls of the case. Each of the four panels 9, 11, 12 and 13 adjoins two rear and front flaps, 14 and 16, 17 and 18, 19 and 21, and 22 and 23, respectively. The flaps 14, 16, 17, 18, 19, 21, 22 and 23 are intended to close the upper and lower sides of this case.

(10) An edge cut 24 forms the distal edge of the distal end part 2 and thus the distal panel 9 of the blank. Parallel longitudinal rear slots 25 are cut from the rear transverse edge of the blank 1 and separate the flaps 14, 17, 19 and 22 adjacent to the rear crease 7. Parallel longitudinal front slots 26 are cut from the front transverse edge of the blank 1 and separate the flaps 16, 18, 21 and 23 adjacent to the front crease 8.

(11) To hold the case together after the folding operation, the distal end panel 9 is glued to the proximal end panel 13. To do this, the proximal end panel 13 has a glue strip or flap 27 that extends beyond the proximal lateral edge of the blank 1. During the folding operation, the distal end panel 9 is folded over the proximal end panel 13 so that the flap 27 is covered by the distal end panel 9. The flap 27 is folded and its lower side is coated with glue. The two end panels 9 and 13 of the blank 1 are fixed one to the other, after the end panel 9 has been folded over the end panel 13 and the flap 27 has been glued to the distal end panel 9, thus joining the four sidewalls 9, 11, 12 and 13 of the case.

(12) The flap 27 is obtained by being cut out from the rest of the blank 1. To do this, the proximal rear slot 25 is cut from the rear transverse edge of the blank 1, parallel to the rear slots 25. A rear cut 31 is made with a substantial slant from the proximal longitudinal edge to the end of the proximal rear slot 25. The proximal front slot 26 is cut from the front transverse edge of the blank 1, parallel to the front slots 26. A front cut 32 is made with a substantial slant from the proximal longitudinal edge to the proximal front slot 26.

(13) A plate element, such as a corrugated-cardboard sheet 35, is printed and cut to obtain the blank 1. The blank 1 is then folded and glued to obtain a case. To do this, a longitudinal packaging production machine 33 (See FIG. 15) preferably comprises a feeder 133 for feeding the machine with sheets 35. A printing unit, for example a flexography printing unit 134, is mounted downstream of and following the feeder 133. A unit for cutting the sheets 35 135, for producing special shapes or handles, is mounted downstream of and following the printing unit 134. A unit 34, or slotter, for processing the sheets 35 (see FIG. 2) is mounted downstream of and following the cutting unit 135. A unit for folding/gluing the blanks 1 136 is mounted downstream of and following the processing unit 34. And a machine outlet 137 for receiving the finished cases is mounted downstream and following the folding/gluing unit 136.

(14) The processing unit 34 processes the printed sheets 35 exiting the printing unit and transforms them into blanks 1. The processing unit 34 is equipped with various toolings that comprise cutting tools or knives that form the edge cut 24, the slots 25 and 26, and the cuts 31 and 32, and creasing tools or creasers that form the longitudinal creases 6. It will be noted that the transverse creases 7 and 8 are produced upstream of the processing unit 34 or are initially provided in the corrugated-cardboard sheets 35.

(15) The tools are mounted on transverse bearing shafts driven in rotation by shaft motors. The speed of rotation of the tools corresponds to the operating speed, i.e. the drive speed and running speed T of the sheets 35.

(16) The processing unit 34 comprises, from upstream to downstream, a precreasing section 36, with a first pair of shafts positioned one above the other. The lower shaft bears a lower precreaser 37 and the upper shaft bears the upper counterpart 38 of the lower precreaser 37. The precreasing section 36 carries out a first initial creasing operation, creasing the longitudinal creases 6.

(17) A first slotting section 39, with a second pair of shafts positioned one above the other, is mounted downstream of the precreasing section 36. The upper shaft of the first slotting section 39 bears a disk equipped with knives 41 and the lower shaft bears a lower counter-blade 42. The first slotting section 39 cuts the rear slots 25.

(18) A creasing section 43, with a third pair of shafts positioned one above the other, is mounted downstream of the first slotting section 39. The lower shaft of the creasing section 43 bears a lower creaser 44 and the upper shaft bears an upper counterpart 46. The creasing section 43 carries out the final creasing operation and thus definitively ensures the retention of the longitudinal creases 6.

(19) A second slotting section 47, with a fourth pair of shafts positioned one above the other, is mounted downstream of the creasing section 43. The upper shaft of the second slotting section 47 bears a roller equipped with knives 48 and the lower shaft bears a lower counterpart 49. The second slotting section 47 cuts the front slots 26.

(20) In order to cut out the glue flap 27, and therefore make the rear cut 31 and the front cut 32 of the flap 27, the processing unit 34 comprises a device 51 for processing the sheets 35. The device 51 is placed in the creasing section 43. Given the proximal position of the flap 27 on the blank 1, the device 51 is mounted on the operator-side end of the upper shaft in the creasing section 43.

(21) The device 51 comprises a central hub 52 rotating (arrow R in FIGS. 2 to 8) about an axis 53 of rotation lying substantially horizontal in a substantially transverse position. The processing tools are mounted on the hub 52 and are each able to process the sheet 35 in a respective processing position as the hub 52 rotates about its axis 53. The hub 52 is cantilevered above the sheet 35.

(22) Two arms 54 and 56 are preferably inserted into the hub 52 and extend radially from the hub 52 (see FIG. 3). A first processing tool, which in this case is a first tool comprising a cutting blade 57, is mounted on the free end of the first arm 54. A second processing tool, which in this case is a tool comprising a cutting blade 58, is mounted on the free end of the second arm 56. The two processing tools are thus cantilevered above the sheet 35. This cantilevered arrangement of the hub 52, the two arms 54 and 56 and the two tools 57 and 58 unweights this device 51, thereby making it possible to reduce the inertia of the device 51 and improve its acceleration and deceleration performance.

(23) The cutting edges of the two cutting tools 57 and 58 are preferably slanted in the horizontal plane relative to the axis 53 of the hub 52, so as to produce the two slanted cuts 31 and 32 in the sheet 35. During the two successive cutting operations, the cutting edge of each of the two cutting tools 57 and 58 is located parallel to the plane of the sheet 35.

(24) It is particularly advantageous for the two arms and thus the two tools 57 and 58 to be positioned radially at an angle α relative to each other, said angle α being substantially smaller than 180° and preferably substantially equal to 100°.

(25) Preferably, and in order to balance the rotation of the device 51, the first arm 54 is extended diametrically by a third arm 59, either forming a counterweight itself or being equipped with a counterweight 61 on its free end. The second arm 56 is extended diametrically by a fourth arm 62, either forming a counterweight itself or being equipped with a counterweight 63 on its free end.

(26) The hub 52 with the two arms 54 and 56 and thus the two tools 57 and 58 and the two counterweight arms 59 and 61 are driven in rotation by virtue of driving means in the form of an electrical motor mounted directly on the axis 53.

(27) To ensure the device 51 makes precise cuts in the sheet 35, the processing unit 34 preferably comprises a counter-tool or counterpart 64. Given the proximal position of the flap 27 on the blank 1, and the mounting of the device 51, the counterpart 64 is mounted on the end located on the operator side of the lower shaft of the creasing section 43. The device 51 and the counterpart 64 are located in between the first slotting section 39 and the second slotting section 47.

(28) The counterpart 64 is a cylinder rotating (arrow C in FIGS. 2 to 8) about a substantially horizontal transverse axis that lies substantially parallel to the axis 53 of rotation of the hub 52 of the device 51. Preferably, the speed of rotation C of the counterpart 64 is synchronized and constant and substantially equivalent to the constant operating speed, i.e. the drive speed and running speed T of the sheets 35. The counterpart 64 is driven separately to the hub 52. The sheet 35 runs in a substantially horizontal plane located between the two tools 57 and 58 and the counterpart 64.

(29) The counterpart 64 is coated with a coating 66 made of a material chosen for its softness, such as a layer of polyurethane for example. The two tools 57 and 58 cut the sheet 35 and penetrate one after the other into the coating of the counterpart 64, thereby making it possible to achieve a sharp, burr-free cut in the sheet 35. By virtue of the polyurethane, the blades of the two tools 57 and 58 wear less and are much less likely to break.

(30) As FIGS. 3 to 8 show, the hub 52 of the device 51 rotates so that the sheet 35 is cut, in succession, in a complete rotation cycle, by the first tool 57 and then by the second tool 58.

(31) The first tool 57 makes contact with the sheet 35 (see FIG. 3). The first tool 57 makes the front cut 32 in the exact location of the flap 27 (see FIG. 4). The first tool 57 disengages from the sheet 35 once the front cut 32 has been made (see FIG. 5). The second tool 58 makes contact with the sheet 35 (see FIG. 6). The second tool 58 makes the rear cut 31 in the exact location of the flap 27 (see FIG. 7). The second tool 58 disengages from the sheet 35 once the rear cut 31 has been made (see FIG. 8). Next, the rotation cycle continues with the following sheet 35.

(32) To enable flaps 27 with various lengths to be cut in sheets 35 of various sizes, and according to the invention, the speed V of rotation R of the hub 52, and therefore of the device 51, varies during a rotation cycle. The phases of variation in speed V for various exemplary flaps 27 are shown in FIGS. 9 to 14 as a function of progress through the rotation cycle.

(33) In any case, the cuts 31 and 32 are cut at a constant speed. During the rotation R cycle, the speed V is first of all, in a first phase 67, kept constant at a speed substantially equal to the operating speed. In this first phase, the first tool 57 is located in its cutting position and makes the front cut 32 in the sheet 35. The speed V is then, in a second phase 68, kept constant at a speed substantially equal to the operating speed. In this second phase the second tool 58 is located in the cutting position and makes the rear cut 31 in the sheet 35.

(34) During the same rotation R cycle, the speed V then varies in at least one variable-speed phase. In this or these phases, each of the two tools 57 and 58 is located in an intermediate position between their respective cutting positions. The intermediate position corresponds to the position of the device 51 at the moment when the tool 57 or disengages from the sheet 35. The speed V varies, the motor driving the hub 52 of the device 51 accelerating or decelerating the rotation R in order to ensure that the cuts 31 and 32 are obtained in the desired locations.

(35) Since the hub 52 is driven independently of the counterpart 64, its inertia is greatly reduced and thus large accelerations and decelerations are possible. The entire range of flap 27 lengths between 100 mm and 700 mm can be covered. In addition, the cuts 31 and 32 may be made at high operating speeds.

(36) This or these phases may be inserted between two constant-speed phases consisting of a first phase in which the first tool 57 is located in the processing position, and a second phase in which the second tool 58 is located in the processing position, in a first rotation cycle of the hub 52. This or these phases may be inserted between two constant-speed phases consisting of a second phase in which the second tool 58 is located in the processing position in a first rotation cycle of the hub 52, and a first phase in which the first tool 57 is located in the processing position, in a second rotation cycle of the hub 52, following the first cycle.

(37) For example, to obtain a flap 27 substantially between 100 mm and 125 mm in length, the variation in the speed V of rotation R (see FIG. 9) comprises, in succession, an acceleration phase 69 and a deceleration phase 71 in between the two constant-speed phases 67 and 68. Next, once the rear cut 31 has been made during the second constant-speed phase 68, the variation in the speed V of rotation R comprises, in succession, a deceleration phase 72, a stop phase 73 and then an acceleration phase 74 before the front cut 32 is reproduced in the following sheet during the first constant-speed phase 67 of the following cycle.

(38) For example, to obtain a flap 27 of substantially 125 mm in length, the speed V of rotation R is kept constant (see FIG. 10) in an intermediate constant-speed phase 76 in between the two constant-speed phases 67 and 68. Next, once the rear cut 31 has been made during the second constant-speed phase 68, the variation in the speed V of rotation R comprises, in succession, a deceleration phase 72, a stop phase 73 and then an acceleration phase 74 before the front cut 32 is reproduced in the following sheet during the first constant-speed phase 67 of the following cycle.

(39) For example, to obtain a flap 27 substantially between 125 mm and 210 mm in length, the variation in the speed V of rotation R (see FIG. 11) comprises, in succession, a deceleration phase 77 and then an acceleration phase 78 in between the two constant-speed phases 67 and 68. Next, once the rear cut 31 has been made during the second constant-speed phase 68, the variation in the speed V of rotation R comprises, in succession, a deceleration phase 72, a stop phase 73 and then an acceleration phase 74 before the front cut 32 is reproduced in the following sheet during the first constant-speed phase 67 of the following cycle.

(40) For example, to obtain a flap 27 substantially between 210 mm and 575 mm in length, the variation in the speed V of rotation R (see FIG. 12) comprises, in succession, a deceleration phase 77 and then a stop phase 79, and then an acceleration phase 78 in between the two constant-speed phases 67 and 68. Next, once the rear cut 31 has been made during the second constant-speed phase 68, the variation in the speed V of rotation R comprises, in succession, a deceleration phase 72 and then an acceleration phase 74 before the front cut 32 is reproduced in the following sheet during the first constant-speed phase 67 of the following cycle.

(41) For example, to obtain a flap 27 substantially 575 mm in length, the variation in the speed V of rotation R (see FIG. 13) comprises, in succession, a deceleration phase 77, a stop phase 79, and then an acceleration phase 78, in between the two constant-speed phases 67 and 68. Next, once the rear cut 31 has been made during the second constant-speed phase 68, the speed V of rotation R remains constant in an intermediate constant-speed phase 81 before the front cut is reproduced in the following sheet during the first constant-speed phase 67 of the following cycle.

(42) For example, to obtain a flap 27 substantially between 575 mm and 700 mm in length, the variation in the speed V of rotation R (see FIG. 14) comprises, in succession, a deceleration phase 77, a stop phase 79, and then an acceleration phase 78, in between the two constant-speed phases 67 and 68. Next, once the rear cut 31 has been made during the second constant-speed phase 68, the variation in the speed V of rotation R comprises, in succession, an acceleration phase 82 and then a deceleration phase 83 before the front cut 32 is reproduced in the following sheet during the first constant-speed phase 67 of the following cycle.

(43) The present invention is not limited to the embodiments described and illustrated. A number of modification may be made without however departing from the scope defined by the breadth of the set of claims.