GRIP SYSTEM AND METHOD FOR INSERTING A SEPARATOR SHEET INTO A RECEPTACLE - Patent application

Abstract

The present invention relates in particular to a gripping system (15) for a sheet transport device for transporting insert sheets to be inserted between rows of folding boxes in a receptacle, the gripping head (15) having at least one support frame (80) and a plurality of suction elements (17, 18) mounted on holding elements (50) received on the support frame (80) so as to be displaceable relative to the support frame (80).

Description

[Technical field]

[0001] The present invention relates to a gripping system for gripping, transporting and inserting an insert sheet between rows of folding boxes in a receptacle. Such a gripping system can be used with a folder-gluer machine. [Background technology]

[0002] The folder-gluer machine glues and folds flat folded boxes that will contain products such as blister packs for medicines or other products, e.g., those packaged in the food or pharmaceutical industries. A plurality of the flat folded boxes can then be subsequently stored in a receptacle (also known as a container) for delivery to the manufacturer.

[0003] Document CH 659627 describes an example of a device for filling receptacles with folded boxes coming from a folder-gluer machine. The folded boxes are delivered by a box conveyor to a receptacle at the end of the folder-gluer machine. Each receptacle may contain a significant number of folded boxes, such as several dozen or even hundreds of boxes.

[0004] The inserting step is necessary to form separate and stable rows of folded boxes in the receptacles. The inserting step consists in placing an insert sheet in an empty receptacle to form a partition between the rows of folded boxes. This act of inserting the insert sheet is necessary, for example, to prevent boxes from crossing during transport of filled receptacles.

[0005] The insert sheet is typically a sheet of cardboard that has been scored and sliced ​​to generally pre-form three parallel fold lines that allow the insert sheet to form a "V" when folded at the fold lines. A flap is positioned on each side of the three parallel fold lines.

[0006] When the two lateral flaps of the insert sheet are brought toward each other, the insert sheet has a three-dimensional shape with a planar fold that is substantially perpendicular to the flaps, the dimensions of the flaps corresponding to the dimensions of the bottom of the receptacle such that the planar fold is positioned vertically when the folded insert sheet is placed in the receptacle.

[0007] In production, a worker is often assigned to manually insert a vertical insert sheet between two rows of boxes. The boxes are then placed on either side of the vertical insert sheet.

[0008] A sheet transport device with a gripping head is known from document WO 2017 / 202500 A1. It serves to insert sheets between rows of folding boxes in a receptacle in the downstream part of a folder-gluer machine.

[0009] WO2017 / 202500 A1 discloses a machine and method for automatically gripping, folding and inserting an insert sheet into a receptacle. The machine has a gripping head for gripping the insert sheet and a drive for moving the gripping head from where the insert sheet is gripped to where the insert sheet is to be placed. The machine is briefly described below with reference to Figures 1 to 9.

[0010] FIG. 1 shows a general view of the elements of a station 1 for filling receptacles 2 (also known as containers) with folding boxes 3, which station 1 can be placed at the outlet of a folder-gluer machine.

[0011] The folded box 3 can be prepared by a folder-gluer machine that glues the folded box 3 and folds it flat, which can then be stored in the folded and glued state with a reduced footprint in the receptacle 2 for transportation purposes. The term "folded box" here means a folded box that has been folded flat for placement in the receptacle 2.

[0012] The receptacle 2 can be, for example, a box of parallelepiped shape capable of holding a number of folding boxes 3. For example, the receptacle 2 is made of cardboard. A receptacle filled with two rows of folding boxes 3 positioned on the edges is shown by way of example in FIG.

[0013] In the filling station 1 as can be seen in Fig. 1, a receptacle conveyor 5 delivers empty receptacles 2 up to a filling zone B where the receptacles 2 are loaded with folding boxes 3. In the loaded state, the receptacles 2 are moved from the filling zone B onto a discharge section Lc (arrow Tb). The loaded receptacles 2 are then discharged along the discharge section Lc to an outlet, which transports the receptacles 2 up to the filling zone B, but in the opposite direction. The loaded receptacles 2 are discharged outside the conveyor 5 (arrow Ld).

[0014] Receptacle 2b can perform a new loading cycle by being reintroduced to the start of the transport to perform a new loading with second level boxes (arrow Te). Receptacle 2b has a capacity and therefore a greater height that allows the entry of second level boxes (see figures 2a and 3c).

[0015] The box conveyor-filler 4 is designed to grip the folded boxes 3, for example arranged in a sheet, at the outlet from the folder-gluer machine and convey them to the filling zone B. The folded boxes 3, which have travelled a substantially arcuate path, are arranged in an orderly fashion in the receptacle 2 by means of the movable end 6 of the box conveyor-filler 4. The folded boxes 3 are thus generally arranged in at least two vertically straight rows of boxes next to one another, the rows being separated by a folded insert sheet 11a (Figure 3a).

[0016] The insert sheet 11a is a sheet of, for example, cardboard, which is creased to pre-form at least three fold lines L1, L2, L3 (see Figures 4a and 4b). The fold lines L1, L2, L3 are parallel to each other. In the folded state, the insert sheet 11a has a planar crease 12 perpendicular to the planar base formed by the two lateral flaps 13a, 13b of the insert sheet 11a and placed one against the other by folding (Figure 4b). The insert sheet 11a is dimensioned such that in the folded state the planar base has dimensions complementary to the dimensions of the bottom surface 14 of the receptacle 2 (Figures 3a, 3b). For example the fold lines L1, L2, L3 are centered so that the planar crease 12 is centered, then the cross section of the folded insert sheet 11a placed on the base will have an inverted T-shape.

[0017] The filling station 1 comprises an insertion device 10 which makes it possible to grab an insert sheet 11 from a stack, fold it along fold lines L1, L2, L3 and then place the folded insert sheet 11 in an empty receptacle 2 before it is filled with folding boxes 3. These operations, also known as "insertion", make it possible to separate and maintain the folding boxes 3 in the receptacle 2 in at least two reliably stable rows.

[0018] For this purpose, the insertion device 10 comprises a gripping head 15 and a drive means 16 designed to displace the gripping head 15 along at least a vertical movement, such as a straight line, and a horizontal movement, for example another straight line.

[0019] The insertion device 10 also comprises a conveyor 5 making it possible to bring successive packs of inserts to ensure a non-stop insertion operation. While the last insert of a pack is being gripped and inserted into a receptacle, the conveyor 5 advances to bring in the next pack of inserts.

[0020] As best seen in FIG. 6, the gripping head 15 comprises at least one first suction element 17a, 17b, at least one second suction element 18a, 18b, at least one linear element 19a, 19b on which the at least one first suction element 17a, 17b is mounted and which can be moved by sliding thereon, as well as a controllable actuation mechanism 20.

[0021] In the example shown in Figures 6, 7a, 7b, 8a, 8b, 9, the gripping head 15 comprises two first suction elements 17a, 17b, two second suction elements 18a, 18b, and two linear elements 19a, 19b. One of the first suction elements 17a and one of the second suction elements 18a are mounted to slide on the first linear element 19a. The other of the first suction elements 17b and the other of the second suction elements 18b are mounted to slide on the second linear element 19b.

[0022] The suction elements 17a, 17b, 18a, 18b are designed to grip the insert sheet 11. They comprise a respective support 23, for example in the form of a bracket, at whose lower end suction openings are arranged. These suction openings are located in a horizontal plane.

[0023] The suction opening is connected to a vacuum source, for example by a flexible hose and at least one valve. A valve, for example a controllable valve, can be positioned between the vacuum source and the flexible hose and controlled by the control unit 30 to establish or cut off low pressure in the suction opening. Thus, when a vacuum is transmitted to the suction opening, the insert sheet 11 can be gripped by suction.

[0024] The suction elements 17a, 17b, 18a, 18b may likewise be provided with suction cups arranged in the area of ​​the suction openings to facilitate gripping of the insert sheet 11 by improving the airtightness between the insert sheet 11 and the suction openings.

[0025] At least the first suction elements 17a, 17b can be displaced by sliding them on the linear elements 19a, 19b by an actuation mechanism 20 between a gripping position (FIGS. 7a, 8a, and 6) and a folded position (FIGS. 7b, 8b, and 9).

[0026] In the gripping position (FIGS. 7a, 8a and 6), the first suction element 17a, 17b and the second suction element 18a, 18b are positioned at a distance from each other, which position allows the suction elements 17a, 17b, 18a, 18b to grip the flat-lying insert sheet 11 by the suction of the lateral flaps 13a, 13b.

[0027] In the folding position (FIGS. 7b, 8b and 9), the first suction element 17a, 17b and the second suction element 18a, 18b are brought closer to each other compared to the gripping position. This proximity of the suction elements 17a, 17b, 18a, 18b makes it possible to fold the insert sheet 11. In order to avoid pinching, especially of the central plane fold 12, gaps are devised between the supports 23 of the suction elements 17a, 17b, 18a, 18b (FIGS. 8b and 9).

[0028] The two first suction elements 17a, 17b are joined to each other by a first support bar 21 and the two second suction elements 18a, 18b are joined to each other by a second support bar 22. The support bars 21, 22 make it possible to ensure good stability for the suction elements 17a, 17b, 18a, 18b as well as to ensure good planarity of the suction openings. Ducts can be devised in the support bars 21, 22, connecting the suction openings to each other and to a common connection 24 of each bar 21, 22 to which a flexible hose connected to the pump can be connected.

[0029] The actuation mechanism 20 is likewise designed to displace the second suction elements 18a, 18b by sliding on the linear elements 19a, 19b between the gripping and folding positions. The actuation mechanism 20 is designed to allow the simultaneous displacement of the support bars 21, 22 towards each other with the same amplitude, which allows the folding of the insert sheet 11 with the central plane crease 12.

[0030] The linear elements 19a, 19b, on which the suction elements 17a, 17b are mounted to slide, comprise, for example, one cylindrical rod each. Complementary cylindrical holes are devised, for example, in the uprights of the supports 23 of the suction elements 17a, 17b, 18a, 18b. The actuation mechanism 20 comprises a controllable actuator 25 and a system connecting the rods.

[0031] The system of connecting rods comprises a vertically movable transverse axle 26 connected to a controllable actuator 25 and at least one connecting rod 27, of which there are four in the present example.

[0032] A first end of the connecting rod 27 is pivotally connected to the transverse axle 26 and a second end of the connecting rod 27 is pivotally connected to the suction elements 17a, 17b, 18a, 18b.

[0033] In this example, each suction element 17a, 17b, 18a, 18b is connected to a transverse axle 26 by a respective connecting rod 27, which passes through a cylindrical opening in a first end of the connecting rod 27. A second end of the connecting rod 27 is pivotally mounted on the support 23, for example by means of a pivot.

[0034] The connecting rods 27 are preferably all of the same size, which allows for simultaneous displacement of the same amplitude relative to the support bars 21, 22 towards or away from each other.

[0035] In operation, the lowering of the transverse axle 26 tilts the connecting rods 27 towards the horizontal, moving the first suction elements 17a, 17b away from the second suction elements 18B, 18b, while the raising of the transverse axle 26 straightens the connecting rods 27, closing the V-shaped openings between them, which brings the first suction elements 17a, 17b closer to the second suction elements 18a, 18b.

[0036] The controllable actuator 25 comprises an electric motor. The actuation mechanism 20 comprises, for example, a screw 28 designed to be driven in rotation by the electric motor, the screw 28 being inserted into the thread of the transverse axle 26 perpendicularly to the transverse axle. The screw 28 is, for example, a ball screw. A ball inserted between the screw 28 and the transverse axle 26 ensures a rolling function, which makes it possible to limit friction and achieve rapid movements.

[0037] Rotation of the electric motor in a first direction drives the elevation of the transverse axle 26 (FIG. 7b), while rotation in the opposite direction drives the descent of the transverse axle 26 (FIG. 7a). The actuation mechanism 20 further comprises at least one guide groove (or slot) 29 designed to cooperate with one end of the transverse axle 26 to guide the vertical displacement of the transverse axle 26. Two guide grooves 29 can thus cooperate with each end of one of the transverse axles 26.

[0038] The insertion device 10 further comprises a control unit 30, such as a computer, control unit or microcontroller unit, comprising a memory and in particular a program making it possible to execute a series of instructions making it possible to control the generation of a vacuum in the drive means 16 and / or the actuation mechanism 20 and / or the first and second suction elements 17a, 17b, 18a, 18b.

[0039] The drive means 16 comprises a linear guide 31 fixed horizontally to the frame and a carriage 32 which can slide along the linear guide 31. The linear guide 31 is for example a rail, a rack or a belt. The drive means 16 likewise comprises a vertically extending arm 33, at the end of which the gripping head 15 is attached. The arm 33 can move vertically in a base carried by the carriage 32.

[0040] The controllable motor of the drive means 16 is designed to displace the carriage 32 along the linear guide 31 and to displace the arm 33 vertically in the base. The drive means 16 allows the control of the vertical displacement of the gripping head 15, i.e. on the one hand, above the working station, so as to lower it to grip the insert sheet 11 and lift it up again, and on the other hand, above the insertion zone E, so as to raise it up again, having lowered the insert sheet 11 into the receptacle 2 and released it. Similarly, the drive means 16 allows the control of the linear horizontal displacement allowing the transport of the insert sheet 11 from the working station to the insertion zone E and the return of the gripping head 15 from the insertion zone E to the working station in order to grip a new insert sheet 11.

[0041] A conveyor 34 may be provided at the workstation for continuously transporting the stack of insert sheets 11 (FIG. 5).

[0042] FIG. 5 in conjunction with FIGS. 8 a, 8 b and 9 shows different stages of the method of gripping, folding and loading the insert sheet 100 by the insertion device 10 .

[0043] The control unit 30 controls the drive 16 to position the gripping head 15 above the insert sheet 11 lying flat on the workstation, and the first and second suction elements 17a, 17b, 18a, 18b are positioned away from each other in the gripping position. The control unit 30 then commands the generation of a vacuum in the first and second suction elements 17a, 17b, 18a, 18b to grip the insert sheet 11, the gripping position allowing gripping of the insert sheet 11 by suction in the area of ​​the side flaps 13a, 13b.

[0044] The control unit 30 then controls the means of controllable displacement with a linear vertical displacement to raise the gripping head 15 and then with a linear horizontal displacement to direct it towards the insertion zone E where the empty and open receptacles 2 are delivered by the conveyor 5 of receptacles. The control unit 30 then commands the rotation of the electric motor to raise the transverse axle 26 (Fig. 7b) and thus straighten the connecting rod 27. The first and second suction elements 17a, 17b, 18a, 18b slide towards each other on the linear elements 19a, 19b, bringing the first suction elements 17a, 17b and the second suction elements 18a, 18b closer to each other, thereby allowing folding of the gripped insert sheet 11 (Fig. 9).

[0045] This folding can be performed in flight, i.e. during the transport of the insert sheet 11 to the insertion zone E, in particular during the horizontal displacement of the gripping head 15. The control unit 30 then commands the drive means 16 to lower the gripping head 15 vertically into the receptacle 2.

[0046] The vacuum is maintained on the suction elements 17a, 17b, 18a, 18b until the head 15 places the insert sheet 11 on the bottom of the receptacle 2. The control unit 30 then commands the vacuum to be stopped, releasing the insert sheet 11. The insert sheet 11 remains folded in the receptacle 2 with the planar fold 12 maintained vertically by the cooperation of the bottom surface 14 and the side flaps 13a, 13b (Figure 3b).

[0047] The control unit 30 then commands the lifting of the gripping head 15 and controls the reverse rotation of the electric motor to lower the transverse axle 26, which is guided by the guide groove 29. The lowering of the transverse axle 26 tilts the connecting rod 27 towards the horizontal, moving the first suction elements 17a, 17b away from the second suction elements 18a, 18b.

[0048] This control of the gripping position can be achieved during the vertical lift or transport of the gripping head 15.

[0049] The receptacle 2 containing the folded insert sheet 11 can then be delivered by the receptacle conveyor 5 along the delivery section La to a filling zone B which can accept the folded boxes 3 delivered by the box transporter-filler 4. [Prior art documents] [Patent documents]

[0050] [Patent Document 1] Swiss Patent No. 659627 [Patent Document 2] International Publication No. 2017 / 202500 Summary of the Invention [Problem to be solved by the invention]

[0051] The object of the present invention is to further improve the machine disclosed in WO2017 / 202500 A1 in order to obtain a more precise and safer control of the vertical movement of the gripping head. This object is solved by a gripping system according to claim 1 and a method for introducing an insert sheet according to claim 17. [Means for solving the problem]

[0052] According to a first aspect, the present invention relates to a gripping system for placing an insert sheet between a row of folding boxes in a receptacle, the gripping system comprising a gripping head configured to grip and pick up the insert sheet from a loading location and to displace and position the insert sheet on a storage surface in the receptacle, the gripping head having a support frame and a plurality of gripping elements configured to adhere to an upper surface of the insert sheet, the gripping elements being connected to the support frame through a plurality of holding elements movably mounted on the support frame, when the gripping elements contact the insert sheet or the storage surface in the receptacle, the holding elements and the gripping elements are movable vertically relative to the support frame, the gripping system further comprising a control unit and a sensing arrangement, the sensing arrangement configured to sense a vertical displacement of the holding elements relative to the support frame, the control unit configured to receive information from the sensing arrangement and determine when the gripping head contacts the insert sheet or the storage surface.

[0053] The vertical direction can be defined as the direction perpendicular to the top surface of the insert sheet, i.e., the normal to the insert sheet. The vertical direction can be aligned with the direction of gravity. As a result, the horizontal direction can be defined by the plane of the insert sheet surface. Furthermore, the horizontal direction can be defined as being 90° to the vertical direction.

[0054] The present invention is based on the realization that the contact of the gripping element on the insert sheet can be adapted to ensure that the insert sheet is stored at the correct height, while at the same time limiting impacts and potential damage to the insert sheet and the row of folding boxes. Thus, the movable gripping and holding elements allow the gripping head to yield in contact with the folding boxes in the receptacle at the correct height to store the insert sheet, and to yield when the gripping element comes into contact with the row of folding boxes in the receptacle. The storage surface can be the top surface of the row of folding boxes or the bottom surface in the receptacle.

[0055] In an embodiment, the control unit is further configured to stop further vertical downward movement of the gripping head when the sensing arrangement senses at least one vertical movement of the gripping elements.

[0056] In an embodiment, the holding element is a rod received in an opening in the support frame, the rod having a free end on which the gripping element is attached. The opening can be a guide opening for the rod. The vertical displacement can therefore be an axial displacement in the longitudinal extension of the holding element.

[0057] The gripping elements can be biased away from the support frame by a biasing member. The biasing member can be mounted around each of the rods and suspended between a first abutment surface located on the support frame and a second abutment surface located on the retaining element. Alternatively, the biasing member is a pneumatic or gas cylinder. The pneumatic cylinder can be mounted inside the leg. The biasing member ensures that the gripping elements are always in a precisely defined position when there is no contact with the insert seat.

[0058] The control unit of the gripping system is configured to control the displacement of the gripping head and actuate the gripping elements alternately between a gripping state and a released state, such that the gripping elements are in the gripping state when the gripping head contacts the insert sheet at the loading location and then the gripping elements are in the released state when the gripping head contacts the storage surface having the insert sheet.

[0059] In an embodiment, the gripping system further comprises a memory comprising spatial coordinates of a first drop position and a second drop position of the gripping head, the first and second drop positions defining start points of first and second vertical drop trajectories, the first descent trajectory being vertically aligned with the loading location and the second descent trajectory being vertically aligned with the storage location, and the control unit configured to actuate the gripping head to move to the first and second drop positions, respectively.

[0060] The endpoints of the first and second vertical descent trajectories may be defined by first and second vertical end positions, the first vertical end position and the second vertical end position being defined solely by the sensing arrangement.

[0061] In an embodiment, the gripping system comprises a linear guide, the gripping head is linearly movable and guided laterally by the linear guide, and the lowering position is defined as a one-dimensional coordinate in a horizontal plane in a direction along the longitudinal extension of the linear guide.

[0062] In an embodiment, the sensing arrangement comprises at least one position sensor positioned on the support frame and at least one detection element positioned on the at least one holding element, the position sensor configured to sense displacement of the detection element.

[0063] For simple systems, one sensor can be used to obtain a representative value of the displacement of the holding element, alternatively, in another embodiment, sensing arrangements can be provided on more than one holding element when additional measurement accuracy is required.

[0064] The sensor may be a magnetic or inductive sensor and the detection element may comprise a metallic material. The detection element may be a mechanical stop mounted on the retaining element, the mechanical stop configured to limit the downward movement of the retaining element relative to the frame. The mechanical stop may be a separate annular part mounted around the rod. The sensor may thus be a position sensor as it is configured to detect a change in position of the detection element.

[0065] In an embodiment, the sensing arrangement comprises a force sensor configured to detect a contact pressure between the gripping element and a contact surface on the insert sheet, thereby making it possible to set different thresholds of contact pressure at which the gripping element should be in a gripped and released state / configuration.

[0066] In another embodiment, at least one of the holding elements may be provided with at least one optically readable reference point and the position detector is an optical sensor.

[0067] In another embodiment, the sensing arrangement can comprise an electromechanical sensing switch having a mechanical latch configured to activate at a predetermined displacement distance of the gripping element, and the control unit is configured to activate and deactivate the gripping element in response to activation of the electromechanical switch. This typically works by initial activation of the switch when the gripping head is in contact with the insert sheet, causing the gripping element to grip the sheet (e.g. the vacuum suction cup is activated). Then the next time the gripping element contacts the surface, the gripping head is over a row of folding boxes in the receptacle and the gripping element is deactivated so that the insert sheet is released. Thus the electromechanical switch can be used alternately to activate and deactivate the gripping element.

[0068] In an embodiment, the support frame comprises a first frame portion having a first group of gripping elements and a second portion having a second group of gripping elements, the first and second frame portions being movable relative to one another between a distal position in which the first and second groups of gripping elements are positioned distally from one another and a proximal position in which the gripping elements are positioned closer to each other than the other distal position, such that the first and second groups of gripping elements are horizontally displaceable relative to one another to provide horizontal displacement and spacing of the gripping elements and thus generate movement that folds the insert sheet.

[0069] In an embodiment, the gripping element can be a suction element configured to apply a suction force to the insert sheet. The holding element can be provided with an internal duct connected to the suction element, and a vacuum line is connected to the rod end opposite the suction element.

[0070] In an embodiment, the control unit is configured to apply a vacuum to the gripping head when the sensor detects a displacement of the gripping element relative to the support frame and when the control unit determines that the gripping head is in a loading location.

[0071] Additionally, the gripping elements can be configured to release air to apply positive pressure against the insert sheet when the control unit determines that the gripping head is in contact with the storage surface.

[0072] The control unit may be configured to stop the downward movement of the gripping head when the sensing arrangement detects a vertical displacement of the gripping element relative to the support frame.

[0073] Preferably, the control unit is configured to gradually stop / slow down the downward movement of the gripping head when the sensing arrangement detects a vertical displacement of the holding element relative to the support frame.

[0074] According to a second aspect, the invention relates to a method for introducing insert sheets into receptacles or between rows of folding boxes by using a gripping head comprising a plurality of gripping elements mounted on vertically displaceable holding elements and movably connected to a support frame, said method comprising the following steps: - moving the gripping head into vertical alignment with the loading location and lowering the gripping head so that the gripping elements contact the upper surface of the insert sheet; - moving the support frame portion further downwards a predetermined distance, whereby the support frame moves relative to the retaining elements and the gripping elements remain stationary relative to the upper surface of the insert sheet; - detecting the displacement of the at least one holding member and stopping further downward movement of the gripping head; - gripping the insert sheet such that the insert sheet adheres to the gripping element; - picking up, displacing and positioning the insert sheet so that it aligns with an opening in the receptacle; - lowering the gripping head to place the insert sheet on a storage surface within the receptacle; - moving the support frame portion further downwards a predetermined distance, whereby the support frame moves relative to the retaining element while the gripping element remains stationary relative to the upper surface of the insert sheet; - detecting the displacement of the at least one gripping element and stopping further downward movement of the gripping head; and - Releasing the gripping element from the insert seat.

[0075] The gripping of the insert sheet can advantageously be performed by suction.

[0076] In an embodiment, the method may further comprise the steps of: - detecting a vertical displacement of the holding element by means of a sensor, and - stopping the vertical movement of the gripping head.

[0077] The present invention will now be described, by way of example only, with reference to embodiments illustrated in the enclosed drawings, in which like reference numerals will be used for similar elements and in which: [Brief description of the drawings]

[0078] [Figure 1] FIG. 1 shows elements of a prior art filling station, in particular a box conveyor / filler, a receptacle conveyor, and an insertion device. [Figure 2a] FIG. 13 shows an example of a receptacle loaded with folded boxes arranged in an orderly fashion with a folded insert sheet inserted between two rows of boxes, with the receptacle having side walls shown as transparent. [Figure 2b] FIG. 13 shows another example of a receptacle loaded with neatly arranged folded boxes with a folded insert sheet inserted between two rows of boxes to provide two levels of folded boxes, with a folded insert sheet inserted between the two levels and with side walls shown as transparent. [Figure 3a]Cross-sectional view of the receptacle, folding box, and insert sheet of FIG. 2a. [Figure 3b] View similar to FIG. 3a with the folding box removed. [Figure 3c] Cross-sectional view of the receptacle, folding box, and insert sheet of FIG. 2b. [Figure 4a] View of the insert sheet before folding as seen from above. [Figure 4b] Perspective view of the insert sheet of FIG. 4a during the folding process. [Diagram 5] Perspective view of the insertion device of FIG. 1. [Figure 6] Perspective view of the gripping head of the insertion device of FIG. 5, where the hood element is shown as transparent and the suction element is shown in the gripping position. [Figure 7a] View of the gripping head of FIG. 6 with the hood element removed to better show the operating mechanism. [Figure 7b] View similar to FIG. 7a with the suction element in the folded position. [Figure 8a] Side view of the gripping head of FIG. 7a. [Figure 8b] Side view of the gripping head of FIG. 7b. [Figure 9] Perspective view of the gripping head of FIG. 7b carrying the insert sheet folded by 180° pivot rotation. [Figure 10] Perspective view of the gripping head according to an embodiment of the present invention. [Figure 11] Side view of the gripping head of FIG. 10 in the condition of descending onto the insert sheet. [Figure 12] Side view of the gripping head of FIG. 10 in the condition of being placed on the insert sheet. [Figure 13] Perspective view of the insert head of FIG. 12 in the condition where the insert sheet is being gripped. [Figure 14] Perspective view of the insert head of FIG. 13 in the condition where the insert sheet is being conveyed. [Figure 15]FIG. 1 is a perspective view of a gripping system according to the present invention; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0079] An embodiment of the invention will now be described below with reference to Figures 10 to 15. For elements that are known from Figures 1 to 9, the same reference numerals are used and only the differences in construction and operation between the prior art gripper head and the gripper head as shown in Figures 10 to 14 will be discussed below.

[0080] The main difference between the gripping systems of the prior art and the gripping system 15' of Figures 10 to 14 is that the gripping elements 17, 18 of the gripping head 15 according to the invention are mounted on the gripping head 15 so as to be displaceable relative to the support bars 21, 22 of the support frame 80. In particular, the gripping elements 17, 18 are mounted so as to be displaceable in a direction which is parallel to the vertical direction along which the gripping head 15 is moved by the drive means 16 when lowering to pick up or store the insert sheet 11.

[0081] In the embodiment shown in the drawings, the gripping elements 17, 18 are attached to the lower end of a holding element 50, here formed as a rod. The lower end of the holding element 50 is configured as a free end, onto which the gripping elements 17, 18 are attached. The holding element 50 is displaceably received in the support bars 21, 22. In the example shown and as can be best seen in Fig. 13, the holding element 50 is received in an opening 52 provided in the support bars 21, 22. The gripping elements 17, 18 are displaceable in a direction determined by the axial extension of the holding element 50.

[0082] A stop 54 is disposed at the upper end of the retaining element 50. The stop 54 abuts the upper surfaces of the support bars 21,22, thereby limiting the downward movement of the retaining element 50 relative to the support bars 21,22.

[0083] Provided on the support frame 80 immediately below the support bars 21,22 (and therefore between the support bars and the gripping elements 17,18) are biasing means 56 for biasing the gripping elements 17,18 away from the support bars 21,22. In the embodiment shown, the biasing means 56 is formed as a compression spring 56 mounted around the rod-shaped retaining element 50. As can be best seen in Figure 14, the compression spring 56 is suspended between a first abutment surface 57 located on the support frame 80 and a second abutment surface 59 located on the retaining element 50.

[0084] As shown in the figures, the gripping elements 17,18 are preferably configured as suction elements 17,18. The suction elements 17,18 are connected to a vacuum generator (not shown). However, other types of mechanical gripping elements are also possible. To apply a vacuum to the suction elements 17,18, a vacuum connection 60 is provided in the gripping head 15. The vacuum connection 60 is connected through a vacuum line 62 to a dispensing line 64, which is in turn connected to the upper end of the holding element 50 (the end opposite to the end provided with the suction elements 17,18).

[0085] From the upper end of the retaining element 50, a bore or duct extends inside the retaining element 50 towards the suction elements 16, 17, so that a vacuum can be applied to the suction elements 17, 18 by applying a vacuum to the vacuum connection 60. The vacuum duct can also be configured to release / blow air to release the vacuum and push the insert sheet 11 away from the suction elements 17, 18 when the insert sheet 11 is to be placed on top of the row of folding boxes 3.

[0086] 13 and 14, associated with at least one of the retaining elements 50 is a sensing arrangement 66 comprising a sensor 70 for detecting a displacement of a detection element 55 located on the respective retaining element 50. The displacement is determined relative to the support 20, 21 to which the retaining element 50 is mounted. The sensor 70 can thus be configured to sense when the detection element 55 is close to the sensor 70, and further configured to sense a displacement when the detection element 55 moves further away from the sensor 70.

[0087] The sensor 70 may be a magnetic or inductive sensor. The sensor 70 is adapted to detect the displacement of each retaining element 50 upwards relative to the position shown in Fig. 11. The detection element 55 may be positioned on the stop 54 and preferably comprises a material detectable by the magnetic or inductive sensor 70. For example, the material may be a metallic material.

[0088] As can be seen in Fig. 14, the detection element 55 on the stop 54 is positioned at the same vertical height as and opposite the sensor 70 when the suction elements 17, 18 are not pressed against the insert sheet 11 (at the loading site or relative to the row of folding boxes). Thus, the sensor 70 and the detection element 55 are aligned when the gripping elements 17, 18 are positioned at their lowest positions where they are placed at the maximum distance from the respective support frames 21, 22. As shown in Fig. 13, the detection element 55 on the stop 54 is positioned further away from the sensor 70 when the suction elements 17, 18 are pressed against the insert sheet 11.

[0089] In the embodiment shown in Fig. 10, the sensing arrangement 66 comprises one sensor 70 and one detection element 55. However, in the embodiment shown in Fig. 13, the gripping system 15' comprises a first sensor 70a and a second sensor 70b that read the first detection element 55a and the second detection element 55b, respectively. This is advantageous when the support frame 80 comprises a first frame part 80a with the first gripping element group 17 and a second frame part 80b with the second gripping element group 18. The control unit 30 can be configured to receive signals from both sensors 70a, 70b and to enable actuation of the gripping elements 17, 18 only when both sensor signals are received. Actuation of the gripping elements 17, 18 is thus enabled when both sensors 70a, 70b determine the displacement of each respective detection element 55a, 55b.

[0090] Preferably, the first sensor 70a and the first detection element 55a are positioned on the first frame portion 80a, and the second sensor 70b and the second detection element 55b are positioned on the second frame portion 80b. In an embodiment, the first sensor 70a and the second sensor 70b are arranged in a diagonal manner on the first and second frame portions 80a, 80b, respectively. In this way, when the insert sheet 11 is gripped, the first and second sensors 70a, 70b are arranged diagonally across the folding lines L1, L2, L3. This allows detection when the insert sheet 11 is not flat at its loading location 9 (e.g., when the stack of insert sheets 11 is not flat). In such a case, when both the first detector 70a and the second detector 70b sense contact with the insert sheet 11 (or the storage location), the gripping head 15 can be actuated to activate the gripping elements 17, 18. Optionally, a threshold distance can be applied to limit further downward movement after the first sensor 70a senses contact. The threshold distance is the vertical distance of the gripping head 15 after the first sensor 70a senses contact. For example, this threshold distance can be set to about 50 mm. This threshold distance allows for the deceleration and stopping of the gripping head 15. Alternatively, a threshold duration can be used instead of the threshold distance. Similarly, the threshold duration is set from the time the first sensor 70a senses contact. The threshold distance or threshold duration allows for the stopping of the gripping head 15 if the second sensor 70b does not sense contact.

[0091] Alternatively, a sensor 70 may be provided on each gripping element 17, 18. In the embodiment shown, there are four sensors 70.

[0092] As best seen in Fig. 15, the gripping head 15 can be linearly actuated in a lateral direction L and a vertical direction V. The lateral direction L lies in a horizontal plane. The lateral direction L can be perpendicular to the transport direction T of the receptacle 2 at the position of the gripping head 15.

[0093] The first drop position P11 of the gripping head 15 can be vertically aligned with the loading position P12 of the insert sheet 11 at the loading location 9. Similarly, the second drop position P21 of the gripping head 15 is positioned in vertical alignment with the storage position P22. The storage position P22 is in the receptacle 2. The first and second drop positions P11, P21 can be defined as coordinates in the memory 35 of the gripping system 15'. In an embodiment, the first and second drop positions P11, P21 are defined only by a first abscissa l1 and a second abscissa l2 in the lateral direction L. The limited movement in the lateral direction L can be achieved by a linear guide 31 configured to guide the gripping head 15 in the lateral direction L.

[0094] Thus, the first drop position P11 can be defined by a one-dimensional spatial coordinate l1. Similarly, the second drop position P21 can be defined by a one-dimensional spatial coordinate l2. These coordinates l1, l2 define the start points (in the horizontal plane) of vertical drop trajectories V1, V2 at the loading location 9 and the storage location 13, respectively. The first drop trajectory V1 at the loading location 9 extends between the first drop position P11 and the first vertical end position P12 (corresponding to the loading position). The second drop trajectory V2 at the storage location 13 extends between the second drop position P21 and the second vertical end position P22.

[0095] In another embodiment, there is no linear guide. In this embodiment, the drop positions P11, P21 are defined in a two-dimensional horizontal plane defined by the longitudinal axis T and the transverse axis L. The coordinates l1, t1; l2, t2 define the drop positions P11, P21.

[0096] The control unit 30 is configured to retrieve descent coordinates l1, l2 that define descent positions P11, P21 from the memory 35. The control unit 30 positions the gripping head 15 at the descent positions P11, P21 and initiates descent of the gripping head 15 in the vertical direction V along descent trajectories V1, V2.

[0097] The first vertical end position P12 and the second vertical end position P22 can be determined solely by the sensing arrangement 66. A stop signal is thus generated by the control unit 30 when the sensing arrangement 66 detects a displacement of at least one detection element 55. Thus, when contact between the gripping elements 17, 18 and a surface is sensed. The surface can be a stack or a row of folding boxes with insert sheets 11. Alternatively, a stop signal is generated when multiple sensors 70a, 70b sense a displacement of the respective detection element 55a, 55b. In yet another embodiment, a stop signal is generated when one sensor senses a displacement and a threshold distance or a threshold time is exceeded.

[0098] The sensing arrangement 66 of the invention thus enables the gripping head 15 to sense the position of the insert sheet 11 at the loading location 9 and also to sense the storage surfaces 13, 14 at the storage location 13. The storage surfaces 13, 14 correspond to the top surfaces 13 of the rows of folding boxes 3 and the bottom surfaces 14 of the receptacles 2.

[0099] This is an important improvement compared to the prior art WO2017 / 202500A1, since it allows to achieve a simpler system that automatically adapts to variable operating conditions. The prior system in WO2017 / 202500A1 required more programming parameters, especially when several layers of insert sheets 11 had to be stored in the receptacle 2 at different heights (as shown in FIG. 2b). The control unit therefore had to retrieve predefined data for each vertical storage position. However, in reality, the vertical position in which the row of folding boxes was actually positioned often differed slightly from the theoretical position. As a result, in order to reduce the risk of damaging the boxes, the gripping head was slowed down before reaching the theoretical storage position, even if a slowdown in speed was feared. In contrast to this, in the system of the present invention, in order to obtain a precise system, merely short set-up times and simple programming of the coordinates of the lowering positions P12, P21 are required.

[0100] In addition to the above mentioned advantages, the gripping system 15' of the present invention also improves reliability and durability. The gripping head 15 will automatically stop even if the sensed object is not a row of insert sheets 11 or folding boxes 3. Also, for example, when an object is present in the descent trajectory V1, V2 of the gripping head 15, the control unit 30 will initiate the stopping of the gripping head 15 when contact with the object is sensed.

[0101] Another improvement in terms of the system of WO2017 / 202500A1 is that the movable gripping elements 17, 18 are also configured to yield when contact with the insert sheet 11 or row of folding boxes is detected. The stroke of the gripping elements 17, 18 can be selected such that the gripping elements 17, 18 are vertically movable after the sensing arrangement 66 detects contact. In this way, the gripping head 15 can still yield against the stack of insert sheets or row of folding boxes.

[0102] Optionally, in an embodiment, the difference in the time lapse between receiving the first sensor signal and receiving the second sensor signal can be measured. When this difference exceeds a predetermined threshold, the control unit 30 can send an error signal to the central machine control system. Such a time difference between the sensor signals may indicate that the insert sheet 11 is picked up or stored on an uneven surface.

[0103] In another (not shown) embodiment, the sensing arrangement 66 comprises an electromechanical sensing switch having a mechanical latch configured to be activated at a predetermined displacement distance of the gripping elements 17, 18. The control unit 30 is configured to activate and deactivate the gripping elements 17, 18 in response to activation of the electromechanical switch. In Figures 10 and 11, the gripping head 15 is shown in a condition prior to being placed on the insert sheet 11. The suction elements 17, 18 have their maximum distance from the respective supports 21, 22, and the supports 21, 22 have their maximum horizontal distance from each other.

[0104] To grip the insert sheet 11, the gripping head 12 moves vertically downwards until the suction elements 17, 18 contact the upper surfaces of the insert sheets 11 arranged in a stack at the loading station 9. This process is best shown in FIG. 1, and this general operating principle also applies to the gripping system 15' of the present invention. This contact stops the suction elements 17, 18 from moving further downwards. As the holding element 50 is vertically movable relative to the support frame 80, the supports 21, 22 move further downwards, which causes the stop 54 to move vertically upwards. This changes the position of the detection element 55 on the stop 54 relative to the supports 21, 22, which can be detected by the sensor 70.

[0105] In response to a corresponding signal from the sensor 70, the control unit 30 prevents the drive means 16 from displacing the gripping head 15 further downwards. In an advantageous embodiment, the control unit 30 is configured to send a command to the actuator 25 to gradually stop / slow down the downward movement of the gripping head 15 when the sensing arrangement 66 detects a vertical displacement of the holding element 50 relative to the support frame 80. The gradual deceleration results in a more controlled and softer contact between the suction elements 17, 18 and the insert sheet. The deceleration distance allows the suction elements 17, 18 to establish a vacuum connection. The biasing device 56 also allows the suction elements 17, 18 to yield when they come into contact with the insert sheet 11, so that any undesired deformation of the insert sheet 11 can be avoided.

[0106] This condition of the gripping head 15 is shown in figure 12. It can be seen that the supports 21, 22 have been displaced downwards on the holding element 50 so that the biasing device 56 is in a compressed state.

[0107] In this condition, a vacuum generator (not shown) is connected to the suction elements 17, 18 and activated so that the respective insert sheets 11 are gripped by the suction elements 17, 18. Then, as shown in Fig. 12, the suction element groups 17, 18 can be moved towards each other in a horizontal direction H to reach the condition shown in Fig. 13, in which the insert sheet 11 is held by the folds 12. This is possible because the first frame part 80a and the second frame part 80b are horizontally movable relative to each other between a distal position, in which the first suction element group 17 and the second suction element group 18 are positioned distal to each other, and a proximal position, in which the first and second groups of suction elements 17, 18 are positioned closer to each other (than in the other distal position).

[0108] In a subsequent step, the gripping head 15 is lifted upwards so that the insert sheet 11 is also lifted, as shown in Figure 14. This causes the biasing device 56 to return to its uncompressed state and to move the suction elements 17, 18 back to the position in which they are located at a maximum distance from the supports 21, 22.

[0109] The insert sheet 11 can then be transported to a position within the storage container where the insert sheet 11 is to be stored. Based on information from the sensing arrangement 66, the control unit 30 determines when the gripper head 15 contacts the bottom of the storage container 2 or the top surface of a row of folding boxes 3 positioned within the storage container 2.

[0110] The control unit 30 then gradually stops / slows down the downward movement of the gripping head 15 and releases the vacuum so that the insert sheet is stored. The suction elements 17, 18 can then be configured to actively release the insert sheet 11 by emitting / blowing air.

[0111] Preferably, as described above, the vacuum ducts in the suction members 17, 18 are configured to release air when the insert sheet 11 is placed on top of the row of folding boxes 3 to release the vacuum and push the insert sheet 11 away from the suction elements 17, 18.

Claims

1. a gripping system (15') for placing an insert sheet (11) between rows of folding boxes in a receptacle (2), said gripping system (15') comprising a gripping head (15) configured to grip and pick up the insert sheet from the loading location (9) and to displace the insert sheet and position it on a storage surface (13, 14) in the receptacle; the gripping head (15) comprises a support frame (80) and a number of gripping elements (17, 18) configured to adhere to the upper surface of the insert sheet (11), the gripping elements being connected to the support frame through a number of holding elements (50) movably mounted on the support frame, the holding elements and the gripping elements being vertically movable relative to the support frame when the gripping elements come into contact with the insert sheet or the storage surface (13, 14) in the receptacle; The gripping system further comprises a control unit (30) and two sensing arrangements (66), the sensing arrangements being arranged in a diagonal manner on the support frame and configured to sense a vertical displacement of the holding element (50) relative to the support frame (80), the control unit being configured to receive information from both sensing arrangements to determine when the gripping head makes contact with the insert sheet or storage surface, and configured to measure a difference in time lapse between receipt of the information from the two sensing arrangements and to send an error signal to a central machine control system when the difference in time lapse exceeds a predetermined threshold. A gripping system (15') characterized in that

2. 2. The gripping system according to claim 1, wherein the storage surface (13, 14) is a top surface (13) of a row of folding boxes (3) or a bottom surface (14) within the receptacle (2).

3. The retaining element (50) is a rod received in an opening (52) in the support frame (21, 22); The rod comprises a free end (53) on which the gripping element is mounted. A gripping system according to claim 1 or 2.

4. The gripping system of any one of claims 1 to 3, wherein the gripping elements are biased away from the support frame by a biasing member (56).

5. The gripping system according to any one of claims 1 to 4, wherein the control unit (30) is configured to control the displacement of the gripping head and to actuate the gripping elements (17, 18) in an alternating manner between a gripping state and a released state such that the gripping elements are in a gripping state when the gripping head contacts the insert seat (11) at the loading location (9) and in a released state when the gripping head next contacts the storage surface (13, 14) having the insert seat.

6. a memory (35) containing the spatial coordinates (l1) of a first lowered position (P11) and the spatial coordinates (l2) of a second lowered position (P21) of the gripping head (15), said first and second drop positions (P11, P21) define the start of a first and second vertical drop trajectory (V1, V2), said first vertical drop trajectory (V1) being vertically aligned with said loading location (9) and said second vertical drop trajectory (V2) being vertically aligned with said storage surface (13, 14), said control unit (30) being configured to actuate said gripping head so that it is moved into said first drop position (P11) and said second drop position (P21), respectively; A gripping system according to any one of claims 1 to 5.

7. the end points of the first and second vertical descent trajectories (V1, V2) are defined by first and second vertical end positions (P12, P22); the first vertical end position (P12) and the second vertical end position (P22) are determined solely by the sensing arrangement (66); The gripping system of claim 6.

8. The gripping system comprises a linear guide (31), The gripping head is linearly movable and is guided in a lateral direction (L) by the linear guide; The lowered position (P11, P21) is defined as one-dimensional coordinates (l1, l2) in a horizontal plane in a direction along the longitudinal extension of the linear guide (31). A gripping system according to any one of claims 6 or 7.

9. The sensing arrangement comprises at least one sensor (70) positioned on the support frame and at least one detection element (55) positioned on at least one holding element (50); the sensor is configured to sense a displacement of the sensing element; A gripping system according to any one of claims 1 to 8.

10. The gripping system of claim 9 , wherein the sensor is a magnetic or inductive sensor and the sensing element comprises a metallic material.

11. said support frame comprising a first frame portion (80a) comprising a first group of gripping elements (17) and a second portion (80b) comprising a second group of gripping elements (18); the first and second frame portions are movable relative to one another such that the first (17) and second groups of gripping elements (18) are horizontally displaceable relative to one another between a distal position in which the first and second groups of gripping elements are positioned distally from one another and a proximal position in which the gripping elements are positioned closer to one another than the distal position; A gripping system according to any one of claims 1 to 10.

12. The gripping system according to any one of claims 1 to 11, wherein the gripping elements (17, 18) are suction elements configured to apply a suction force to the insert sheet.

13. 10. The gripping system of claim 9, wherein the control unit (30) is configured to apply a vacuum to the gripping head (50) when the sensor (70) detects a displacement of the holding element (50) relative to the support frame (21, 22) and when the control unit determines that the gripping head is at the loading location (9).

14. 14. The gripping system of claim 13, wherein the gripping element is configured to emit air to apply a positive pressure against the insert sheet when the control unit determines that the gripping head is in contact with the storage surface.

15. The gripping system of any one of claims 1 to 14, wherein the control unit is configured to gradually stop / slow down the downward movement of the gripping head when the sensing arrangement detects a vertical displacement of the holding element (50) relative to the support frame (80).

16. A method for introducing insert sheets (11) into receptacles or between rows of folding boxes by using a gripping head with a plurality of gripping elements (17, 18) mounted on vertically displaceable holding elements (50) each movably connected to a pair of support frames (80), comprising: moving the gripping head (15) into vertical alignment with a loading location (9) and lowering the gripping head so that the gripping elements contact the upper surface of the insert sheet; moving the support frame further downward a predetermined distance whereby the support frame moves relative to the retention elements and the gripping elements remain stationary relative to the top surface of the insert sheet; detecting a displacement of at least one holding element by two sensing arrangements arranged in a diagonal manner on the support frame and measuring a difference in a time lapse at which both of the two sensing arrangements sense the displacement of the holding element, and stopping further downward movement of the gripping head when the difference in the time lapse exceeds a predetermined threshold value; gripping the insert sheet such that the insert sheet adheres to the gripping element; moving the first support frame (80a) closer towards the second support frame (80b) so that the insert sheet is folded; picking up, displacing and positioning the insert sheet so that the insert sheet aligns with an opening in the receptacle; lowering the gripping head and placing the insert sheet on a storage surface (13, 14) within the receptacle; moving the support frame further downwards a predetermined distance, whereby the support frame moves relative to the retaining elements while the insert seat remains stationary relative to the storage surface (13, 14); detecting a displacement of at least one gripping element and stopping further downward movement of the gripping head; Releasing the gripping element from the insert sheet; 13. A method comprising:

17. detecting a vertical displacement of the retaining element relative to the support frame using a sensor; stopping vertical movement of the gripper head; The method of claim 16 further comprising:

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