Bag inversion device

Abstract

To provide a bag reversing device allowed to reverse an array of superposed packaging bags formed by partially superposing a plurality of packaging bags together and to adjust the length of an overlap of superposed packaging bags constituting the array of superposed packaging bags.SOLUTION: A bag reversing device 10 comprises a feed conveyor 11, a reversing unit 12 having a reversing pathway R, and an unloading conveyor 13. A forward-directed array of superposed packaging bags Cf, formed by superposing a former-half portion of a succeeding packaging bag over a latter-half portion of a preceding packaging bag on the feed conveyor, passes the reversing pathway and is then reversed onto a reverse-directed array of superposed packaging bags Cr formed by superposing a former-half portion of a succeeding packaging bag below a latter-half portion of a preceding packaging bag. On this occasion, by changing the moving speed of a reversing belt 26 relatively to the rotation speed of a reversing drum 25, an overlap where the preceding and succeeding packaging bags are superposed together can be adjusted in its length.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to a bag reversing device for reversing the front and back sides of a packaging bag when feeding the packaging bag to a packaging machine.

Background Art

[0002] A packaging machine that manufactures bag products by filling articles to be packaged into packaging bags is configured to perform processes related to predetermined packaging steps while moving the packaging bags along a predetermined conveying path. A bag feeding device that supplies packaging bags to the conveying path includes a packaging bag stocker that stacks and stores a plurality of packaging bags, and a bag feeding conveyor that pulls out the packaging bags one by one from the lowermost end of the packaging bags stored in the packaging bag stocker and conveys them to the bag feeding device. When the belt surface of the bag feeding conveyor comes into contact with the lower surface side of a first packaging bag, the first packaging bag slides against the lower surface side of another packaging bag stacked on the upper surface side thereof, and is pulled out from the packaging bag stocker. Then, when the first packaging bag is pulled out to a certain extent, the lower surface side of another packaging bag comes into contact with the belt surface of the bag feeding conveyor. At this time, since the upper surface side of said another packaging bag slides against the further stacked packaging bags compared to the lower surface side, the first packaging bag and said another packaging bag are pulled out from the packaging bag stocker while partially overlapping each other. In this way, on the bag feeding conveyor, a plurality of packaging bags partially overlapping each other are placed in a row. Hereinafter, this is referred to as a forward overlapping row of packaging bags. In such an overlapping row of packaging bags, the subsequently pulled-out packaging bag overlaps the previously pulled-out packaging bag in the traveling direction of the bag feeding conveyor. Therefore, when the preceding packaging bag is to be fed to the conveying path on the packaging machine side, the preceding packaging bag is sandwiched between the belt surface of the bag feeding conveyor and the lower surface side of the subsequent packaging bag, so it may get caught on the belt surface due to friction, static electricity or the like, or stick to other packaging bags, which may hinder the operation of the bag feeding device. Therefore, the inventors of the present invention conceived that by having the later packaging bag overlap the lower surface of the earlier packaging bag, that is, by reversing the front and back of the forward-facing overlapping row of packaging bags to form an overlapping row of packaging bags in the reverse direction, it would be possible to prevent problems during bag dispensing.

[0003] Here, a bag reversing device for flipping the front and back of a packaging bag is disclosed in Japanese Patent Publication No. 2017-186056. The bag inversion device is a device for inverting packaged bags in a stage prior to the printing inspection process or the final boxing process, and consists of a supply unit equipped with a supply belt that travels continuously with the packaged bags along an inversion area having an arc-shaped path, a transport and holding unit equipped with a holding belt that holds the packaged bags together with the supply belt while facing the supply belt in the inversion area, a tension adjustment unit that adjusts the tension of the holding belt to press the holding belt against the supply belt, and an output unit from which the packaged bags are discharged from the inversion area. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2017-186056 [Overview of the project] [Problems that the invention aims to solve]

[0005] However, the bag reversing device described above is configured such that, when packaging bags overlap, it moves the holding belt that is holding the packaging bags relatively away from the supply belt, thereby discharging the overlapping packaging bags outside the packaging process. Therefore, when supplying packaging bags to a bag-feeding device, it is not possible to form a stack of overlapping packaging bags by reducing the distance between the first-to-last-supplied packaging bag and the second-to-last-supplied packaging bag, thereby saving space and improving work efficiency. Furthermore, the bag inversion device described above is configured such that the control unit uniquely determines the feed speed of the holding belt in relation to the feed speed of the supply belt, so that the packaging bags do not overlap. Therefore, because the front and back of the packaging bags are simply reversed, it is not possible to reduce the distance between the first and second packaging bags to form a superimposed row of packaging bags where parts of the bags overlap, nor is it possible to adjust the length of the overlapping portion where the first and second packaging bags overlap.

[0006] Therefore, the problem that the present invention aims to solve is to provide a bag reversal device that can reverse a stack of overlapping packaging bags formed by overlapping parts of multiple packaging bags, and that can adjust the length of the overlapping portion between the overlapping packaging bags constituting the stack of overlapping packaging bags. [Means for solving the problem]

[0007] The bag reversing device according to claim 1 includes a supply conveyor having a supply belt that has its starting end on the side of a packaging bag stocker for stacking and stocking multiple packaging bags, and that continuously pulls out one packaging bag at a time from the bottommost packaging bag stocked in the packaging bag stocker, A cylindrical reversing drum connected to the end of the supply conveyor, which rotates at a predetermined rotational speed, and A reversing drum drive unit that rotates the reversing drum at a predetermined rotational speed, and A reversing belt is positioned opposite the peripheral wall surface of the reversing drum and travels continuously while being biased toward the peripheral wall surface. a reversing belt drive unit that drives the reversing belt at a predetermined belt speed, and a control unit that independently controls the reversing drum drive unit and the reversing belt drive unit. It comprises a reversing section that sandwiches the packaging bag between the peripheral wall surface and the belt surface of the reversing belt to reverse the front and back of the packaging bag, It consists of a discharge conveyor equipped with a discharge belt that continuously discharges the packaging bags that have been reversed after passing through the reversing section, The supply conveyor overlaps the front portion of a later-pulled-out packaging bag onto the rear portion of a later-pulled-out packaging bag, along the direction of travel of the supply belt, thereby forming a forward-facing overlapping row of packaging bags in which multiple packaging bags are arranged in a row with parts of each other overlapping. The reversing unit sandwiches the forward-facing stack of packaging bags between the peripheral wall surface and the belt surface, rotating it approximately halfway along the reversing drum, so that the front half of the later stack of packaging bags overlaps the rear half of the earlier stack of packaging bags, thus reversing it into the reverse-facing stack of packaging bags. At the same time, the control unit changes the belt speed of the reversing belt driven by the reversing belt drive unit relative to the rotational speed of the reversing drum driven by the reversing drum drive unit. Adjust the overlap length where the preceding packaging bag and the following packaging bag in the aforementioned stacking row of packaging bags overlap. do, The discharge conveyor is characterized in that it discharges the stacked packaging bags in the reverse direction using the discharge belt.

[0008] Claim 2 The bag reversing device described in claim 1 comprises a plurality of reversing rollers, each consisting of a main reversing roller that supports the reversing belt and at least one follower reversing roller that supports the reversing belt and moves in accordance with the main reversing roller. The reversing belt is characterized by consisting of a plurality of round belts arranged at equal intervals along the axial direction of the reversing roller.

[0009] Claim 3 The bag inversion device described above is In the invention described in claim 1, The reversing section is characterized by being provided with a tension adjustment mechanism that adjusts the tension of the reversing belt to adjust the pressure that clamps the stacked packaging bags between the reversing belt and the reversing drum.

[0010] Claim 4 The bag reversing device described in claim 1 is characterized in that the supply conveyor is provided with a feeding mechanism that feeds the packaging bags drawn out from the packaging bag stocker toward the reversing section and forms a forward stack of the packaging bags. [Effects of the Invention]

[0011] According to the bag reversing device of the present invention, on a supply conveyor, the front half portion of a later-drawn packaging bag is placed on top of the rear half portion of a earlier-drawn packaging bag from a packaging bag stocker, and multiple packaging bags with parts of each other overlapping are arranged in a row to form a forward-facing overlapping row of packaging bags. These are then sandwiched between a reversing drum and a reversing belt and rotated approximately half a turn along the peripheral wall of the reversing drum, thereby reversing them into a reverse-facing overlapping row of packaging bags, where the front half portion of the later-drawn packaging bag overlaps the rear half portion of the earlier-drawn packaging bag. This allows a stack of overlapping packaging bags, consisting of multiple bags partially overlapping each other, to be continuously flipped over so that the preceding packaging bag overlaps the following one. Therefore, when the bag-feeding device supplies packaging bags to the transport path of the packaging machine near the end of the discharge conveyor, the packaging bag located at the front and top of the stack of overlapping packaging bags can be supplied to the transport path, allowing the bag-feeding device to smoothly handle the transfer of packaging bags. Preferably, the belt speed of the reversing belt is controlled relative to the rotation speed of the reversing drum to adjust the overlap length, which is the length of the overlapping portion where the first and second packaging bags overlap. This allows for optimizing the spacing between packaging bags in accordance with the timing of the bag-feeding device supplying bags to the transport path. This can be achieved by either filling the later packaging bag with the earlier packaging bag at the reversing section to increase the number of packaging bags per unit length of the stacked packaging bag rows on the transport conveyor, or by delaying the later packaging bag with the earlier packaging bag to decrease the number of packaging bags per unit length of the stacked packaging bag rows on the transport conveyor. Preferably, the continuously moving reversing belt is supported by a plurality of reversing rollers, each consisting of a main reversing roller and at least one dependent reversing roller that is driven by the main reversing roller via the reversing belt, and the reversing belt is composed of a plurality of round belts arranged at equal intervals along the axial direction of the reversing rollers. Accordingly, replacement of the reversing belt can be facilitated and the cost of parts for the flat belt can be reduced, compared with using a large reversing belt constituted by a flat belt having a width facing the reversing drum. More preferably, a tension adjusting mechanism for adjusting the tension of the reversing belt is provided to adjust the pressure applied by the reversing belt to the stacked packaging bags sandwiched between the reversing belt and the reversing drum. Accordingly, the sandwiching pressure can be optimized in accordance with the thickness of the packaging bags or the thickness of the stacked overlapping packaging bags. Further, when changing the overlap length between the preceding packaging bag and the following packaging bag, weakening the sandwiching pressure makes it easier to adjust the position of the following packaging bag relative to the preceding packaging bag, or strengthening the sandwiching pressure makes it difficult for the following packaging bag to shift after its position relative to the preceding packaging bag is determined. Still more preferably, a feeding mechanism is provided which feeds out the packaging bags pulled out from a packaging bag stocker toward the reversing section and forms a forward stacked row of packaging bags. Accordingly, this prevents the packaging bags pulled out from the packaging bag stocker from jamming near the packaging bag outlet of the packaging bag stocker, and prevents the pulled-out packaging bags from warping upward, thereby forming a forward stacked row of packaging bags in which the front half of the following packaging bag overlaps the rear half of the preceding packaging bag, and can feed the stacked row of packaging bags to the reversing section. [BRIEF DESCRIPTION OF THE DRAWINGS]

[0012] [Figure 1] It is a side view showing an outline of a configuration of a bag reversing device according to a first embodiment. [Figure 2] It is an explanatory view showing an outline of the configuration of the bag reversing device according to the first embodiment. [Figure 3] It is an explanatory view showing an outline of configurations of a reversing belt constituting the bag reversing device according to the first embodiment and a reversing roller supporting the reversing belt. [Figure 4] It is an explanatory view showing an outline of a flow of packaging bags when the bag reversing device according to the first embodiment operates. [Figure 5]It is an explanatory diagram schematically illustrating a step of feeding a packaging bag inverted by the bag inverting device according to the first embodiment. [Example 1]

[0013] An embodiment of the bag inverting device according to the present invention will be described with reference to the accompanying drawings. Figure 1 is a side view schematically showing the configuration of the bag inverting device according to the present embodiment.

[0014] As shown in Figure 1, the bag inverting device 10 comprises a feeding conveyor 11, an inverting section 12, an unloading conveyor 13, and a control section (not shown in the figure). The feeding conveyor 11 comprises a feeding belt 15 that travels from the packaging bag stocker 100 toward the inverting section 12, and a feeding belt driving section 16 that drives the feeding belt 15. The packaging bag stocker 100 is formed of a box body having an upper end opening and a lower end opening. A bundle of packaging bags formed by stacking a plurality of packaging bags B into a bundle can be loaded through the upper end opening. The starting end of the feeding belt 15 is disposed below the lower end opening. With this configuration, the lowermost packaging bag B of the bundle of packaging bags stocked in the packaging bag stocker 100 is in contact with the feeding belt 15, and is pulled out one by one as the feeding belt 15 travels. As shown in Figure 2, the feeding belt 15 is stretched between a main feeding rotor 17 and a driven feeding rotor 18 driven by the main feeding rotor 17, and is configured such that the belt surface continuously travels from the starting end on the packaging bag stocker 100 side toward the terminal end on the inverting section side. The packaging bags B located at the lowermost end of the bundle of packaging bags, which abut against the belt surface on the starting end side, i.e., below the lower end opening of the packaging bag stocker, are pulled out one by one as the feeding belt 15 travels, and fed to the inverting section 12 on the terminal end side. At this time, when the bottommost packaging bag (hereinafter referred to as the "first packaging bag") that is pulled out first from the packaging bag stocker 100 is transported to the supply belt 15, it is stacked on top of the bottommost packaging bag, and the packaging bag that is pulled out later (hereinafter referred to as the "second packaging bag") comes into contact with the surface of the belt and is pulled out with a portion overlapping with the first packaging bag. As this is repeated as the supply belt 15 moves continuously, the front half of the second packaging bag is overlapped on top of the rear half of the first packaging bag along the direction of travel of the supply belt 15, and a packaging bag overlapping row C is formed on the supply conveyor 11 in which multiple packaging bags are lined up with a portion overlapping with each other. This packaging bag overlapping row C will be referred to as the forward packaging bag overlapping row Cf below. The supply belt drive unit 16 has a supply motor (not shown) that rotates at a predetermined rotational speed, and is configured to rotate a supply main rotor 17 connected to the supply motor to make the supply belt 15 travel at a predetermined speed.

[0015] Preferably, a supply tensioner 19 may be provided to adjust the tension of the supply belt 15. This allows the tension on the belt surface between the start and end of the supply belt 15 to be adjusted according to the weight of the stocked packaging bags B, thereby keeping the belt surface flat. Furthermore, preferably, as shown in Figure 1, a dispensing mechanism 20 may be provided in front of the outlet of the packaging bag stocker 100 of the supply conveyor 11. The feeding mechanism 20 includes a feeding rotor 21 biased toward the belt surface of the supply belt 15, and a feeding rotor drive unit 22 that rotates the feeding rotor 21 at a predetermined rotational speed. The dispensing rotor 21 is configured to hold the packaging bags B, which have been drawn out from the packaging bag stocker 100, between the peripheral wall surface of the dispensing rotor 21 and the supply belt 15 with a predetermined pressure. The feed rotor drive unit 22 has a feed motor (not shown) that rotates at a predetermined rotational speed, and is configured to rotate the feed rotor 21 connected to the feed motor at a predetermined rotational speed. This allows the packaging bag B to be fed out toward the reversing section along the direction of travel of the supply belt 15. As described above, in the forward direction, the overlapping row of packaging bags Cf is formed by overlapping the front portion of the later packaging bag with the rear portion of the earlier packaging bag. Therefore, when packaging bag B is pulled out from the packaging bag stocker 100, there is a risk that the front end of the later packaging bag may lift up or get caught in the outlet of the packaging bag stocker 100 and bend backward. In contrast, the dispensing rotor 21 is biased with a predetermined pressure toward the belt surface of the supply belt 15, so that the front end of the packaging bag B that is curling or floating can be pressed toward the supply belt 15. This prevents the packaging bag B drawn from the packaging bag stocker 100 from curling or the front end of the packaging bag B that is floating toward the direction of travel of the supply belt 15 from floating.

[0016] As shown in Figure 1, the reversing unit 12 includes a reversing drum 25 and a reversing belt 26 positioned opposite the peripheral wall surface of the reversing drum 25. The reversing drum 25 consists of a cylindrical drum body and a reversing drum drive unit 27 that rotates the drum body at a predetermined rotational speed. The peripheral wall surface of the drum body is processed to prevent the packaging bag B from slipping, for example, by forming irregularities on the surface or by attaching or wrapping a non-slip material such as rubber. This allows the supplied packaging bag B to be moved and reversed without slipping. The reversing drum drive unit 27 has a reversing drum motor (not shown) which is a servo motor. The reversing drum motor rotates at a predetermined rotational speed, causing the connected drum body to rotate at a predetermined rotational speed. Furthermore, the reversing drum 25 is not limited to a configuration in which only the drum body rotates; it may also be configured to include a belt that winds around the drum body, and the belt is driven by rotating the drum body with the reversing drum drive unit 27.

[0017] As shown in Figure 2, the reversing belt 26 includes a plurality of reversing rollers that support the reversing belt 26, a reversing belt drive unit 28 that causes the reversing belt 26 to run continuously at a predetermined speed, and a tension adjustment mechanism 29 that adjusts the tension of the reversing belt. The multiple reversing rollers consist of a main reversing roller 30 and at least one, in this embodiment, two, follower reversing rollers 31. The main reversing roller 30 is connected to the reversing belt drive unit 28. As shown in Figure 2, the follower reversing rollers 31 support the reversing belt 26 together with the main reversing roller 30 and are driven by the main reversing roller 30 via the reversing belt 26. The reversing belt drive unit 28 has a reversing belt motor 32 which is a servo motor. The reversing belt motor 32 rotates at a predetermined speed and rotates the connected reversing main roller 30 at a predetermined speed. The reversing main roller 30, which rotates at the predetermined speed, causes the reversing belt 26 to run continuously at a predetermined speed. The tension adjustment mechanism 29 has a tension roller 33 that is driven by the reversing main roller 30 via the reversing belt 26 and is positioned to move toward and away from the reversing drum 25. When the tension roller 33 is brought closer to the reversing drum 25, the tension of the reversing belt 26 can be loosened, and when it is moved away from the reversing drum 25, the tension of the reversing belt 26 can be increased. In this way, the tension adjustment mechanism 29 can appropriately adjust the tension of the reversing belt 26 according to the thickness or flexibility of the packaging bag B or the overlapping row of packaging bags Cf, and bias the reversing belt 26 toward the peripheral wall surface of the reversing drum 25 with a predetermined pressure.

[0018] The reversing belt 26 is composed of round belts arranged at equal intervals along the axial direction of the reversing roller, which consists of a main reversing roller 30 and a secondary reversing roller 31, as shown in Figure 3. As shown in Figure 3, the reversing roller has multiple guide grooves 34 formed at equal intervals, and a round belt is fitted into each guide groove 34. In Figure 3, a portion of the round belt is omitted to show the guide grooves 34, but a round belt may be fitted into all of the guide grooves 34, or the round belts may be arranged at predetermined intervals, such as fitting a round belt into every other guide groove 34. By using multiple round belts, belt replacement can be made easier than using a single wide flat belt, and costs can be reduced when using round belts compared to flat belts. Furthermore, since the reversing belt 26 is configured to bias the packaging bag toward the peripheral wall surface of the reversing drum 25, using a round belt that only partially contacts the surface of the packaging bag in a linear manner is less likely to cause problems such as the belt rubbing off printed text, images, etc. on the packaging bag or soiling the packaging bag, compared to a flat belt that is in close contact with the surface of the packaging bag as a whole. Furthermore, the reversing belt 26 is not limited to a round belt; a flat belt with a width opposite to the width of the reversing drum may be used, or a mesh-like belt with holes punched at predetermined intervals, or a striped belt with gaps at predetermined intervals may be used.

[0019] Here, the arc-shaped gap formed between the peripheral walls of the opposing reversing drums 25 and the reversing belt 26 is defined as the reversing path R from the supply conveyor 11 to the discharge conveyor 13. As shown in Figure 2, the reversing unit 12 having the above configuration is configured to allow a forward stack of packaging bags Cf to be inserted from the supply conveyor 11 side of the reversing path R. The forward stack of packaging bags Cf inserted into the reversing path R is biased toward the peripheral wall surface of the reversing drum 25 by the reversing belt 26 and moves along the reversing path R toward the discharge conveyor 13 side as the reversing drum 25 rotates and the reversing belt 26 moves. As shown in Figure 2, the reversal path R is arc-shaped, so when it travels approximately half a turn from the supply conveyor 11 end to the discharge conveyor 13 end, the overlapping stack of packaging bags C, which is sandwiched in the reversal path R, is inverted vertically. As shown in Figure 5, the inverted overlapping stack of packaging bags C is formed with the front half of the later packaging bag B overlapping and connected below the rear half of the earlier packaging bag B. The state of the inverted overlapping stack of packaging bags C on the discharge conveyor is as if the forward overlapping stack of packaging bags Cf were reversed, so this is called the reverse overlapping stack of packaging bags Cr. As shown in Figure 5, the reverse overlapping stack of packaging bags Cr is formed with the leading packaging bag that has reached the end of the discharge conveyor 13 positioned at the top of the stack, and from there toward the reversal path R, the later packaging bags are arranged in a row so that they overlap below the earlier packaging bags. In this way, the reversal unit 12 can move the forward-facing stack of packaging bags Cf along the reversal path R and reverse it into the reverse-facing stack of packaging bags Cr.

[0020] As shown in Figure 1, the discharge conveyor 13 consists of a discharge belt 35 that travels from the reversing section 12 toward the bag feeding conveyor 110, and a discharge belt drive section 36 that drives the discharge belt 35. When the stacked rows of packaging bags Cr in the reverse direction are transferred from the discharge conveyor 13 to the bag-feeding conveyor 110, as shown in Figure 5, at the end of the bag-feeding conveyor 110, a bag-feeding process is performed in which a bag-feeding arm 120 equipped with a suction cup 120a at its tip sucks up and lifts the packaging bag B, and transfers the packaging bag B to a gripper device 130 that circulates along the packaging bag transport path formed on the packaging machine side. Here, the reverse-direction stacked This prevents feeding problems in the packaging bag feeding process, where the suction cup 120a is used to attract the vicinity of the opening end of the packaging bag B and transfer it to the gripper device 130. These problems can occur due to friction or other resistance on the surfaces where the first and second packaging bags are in contact, or due to the weight of the second packaging bag placed on top of the first packaging bag.

[0021] The control unit is configured to independently control each of the drive units, namely the reversing drum drive unit 27, the reversing belt drive unit 28, the supply belt drive unit 16, the discharge belt drive unit 36, and more preferably the feed rotor drive unit 20.

[0022] The control unit is configured to control the reversing drum drive unit 27 and the reversing belt drive unit 28 separately and independently. This allows the rotational speed of the reversing drum 25 driven by the reversing drum drive unit 27 and the travel speed of the reversing belt 26 driven by the reversing belt drive unit 28 to be changed relative to the speed of the other. As the reversing drum 25 and the reversing belt 26 move relative to each other, the length over which the preceding packaging bag B and the following packaging bag B that form the overlapping row C overlap along the reversing path R can be changed along the reversing path R. The length of the portion over which the preceding packaging bag and the following packaging bag overlap along the reversing path R is defined as the overlap length. When the rotational speed of the reversing drum 25 and the travel speed of the reversing belt 26 are set to the same speed, the overlap length of the forward-facing stack of packaging bags Cf formed on the supply belt 15 remains unchanged, and the number of packaging bags B contained per unit length also remains unchanged as the stack is reversed, and the reverse-facing stack of packaging bags Cr is discharged towards the discharge belt 35. When the travel speed of the reversing belt 26 is made relatively faster than the rotation speed of the reversing drum 25, the overlap length of the forward-facing stack of packaging bags Cf formed on the supply belt 15 increases, the number of packaging bags B included per unit length increases, and the reverse-facing stack of packaging bags Cr is discharged towards the discharge belt 35. When the travel speed of the reversing belt 26 is made relatively slower than the rotation speed of the reversing drum 25, the overlap length of the forward-facing stack of packaging bags Cf formed on the supply belt 15 is shortened, reducing the number of packaging bags B per unit length, and the reverse-facing stack of packaging bags Cr is discharged towards the discharge belt 35. As described above, by inverting the packaging bags on the inversion path R and simultaneously adjusting the overlap length of the overlapping packaging bags, the inversion unit 12 can invert the overlapping rows C of packaging bags from the forward direction to the reverse direction while correcting the overlap to the optimal degree each time during bag feeding. Furthermore, the system is not limited to changing the travel speed of the reversing belt 26 based on the rotational speed of the reversing drum 25 as described above; it may also be configured to change the rotational speed of the reversing drum 25 based on the travel speed of the reversing belt 26.

[0023] Furthermore, the control unit is configured to control the supply belt drive unit 16, and preferably the feed rotor drive unit 20, to drive at a steady, predetermined speed based on the rotational speed of the reversing drum 25. As a result, the supply belt drive unit 16 and the dispensing rotor drive unit 20 can transport the forward stacked rows of packaging bags Cf by synchronizing the travel speed of the supply belt 15 with the rotation speed of the reversing drum 25, thereby preventing problems such as the forward stacked rows of packaging bags Cf getting jammed at the entrance of the reversing unit 12. The control unit is configured to control the discharge belt drive unit 36 ​​to drive at a constant predetermined speed based on the travel speed of the reversing belt 26. As a result, the discharge belt drive unit 36 ​​can transport the overlapping rows of packaging bags Cr in the reverse direction by synchronizing the travel speed of the discharge belt 35 with the travel speed of the reversing belt 26, and can receive the overlapping rows of packaging bags Cr in the reverse direction after adjusting the overlap length onto the discharge belt 35 and hand them over to the next bag feeding conveyor 110.

[0024] The method of using the bag inversion device 10 having the above configuration will be explained in accordance with the attached drawings, focusing on the movement of the packaging bag B.

[0025] As shown in Figure 4, the packaging bags B are stacked and stored in the packaging bag stocker 100. A supply conveyor 11 is located below the packaging bag stocker 100, so when the bag inversion device 10 operates and the supply conveyor 11 starts moving, the packaging bags are pulled out of the packaging bag stocker 100 one by one by the supply belt 15, starting with the bottommost packaging bag B inside the stocker 100. When the bottommost packaging bag B is pulled out, the second-to-last packaging bag B, which is stacked on top of it, comes into contact with the supply belt 15. As long as the area of ​​this contact is small, that is, as long as a large portion of it overlaps with the bottommost packaging bag B, the friction between the weight of the bundle of packaging bags on top of the second packaging bag B and the third packaging bag B stacked on top of the second packaging bag B is greater than the frictional force with the supply belt 15. As a result, the second packaging bag B does not move, and only the bottommost packaging bag B is pulled out. Then, when the area of ​​the second packaging bag B in contact with the supply belt 15 reaches a predetermined size, the frictional force between the second packaging bag B and the supply belt 15 causes it to move against the weight of the bundle of packaging bags, the frictional force with the third packaging bag B, and static electricity attraction. At this time, the latter half of the bottommost packaging bag B and the front half of the second packaging bag B overlap and are pulled out from the packaging bag stocker 100 as shown in Figure 4. In this way, a portion of the packaging bag B that is drawn out first from the packaging bag stocker 100 is superimposed on the packaging bag B that is drawn out later, and they are arranged in a row on the supply belt 15 to form a forward-facing overlapping row of packaging bags Cf. Preferably, the supply belt 15 and the dispensing rotor 21 may be used to sandwich the forward stack of packaging bags Cf. This prevents the later packaging bag B from lifting up or curling up relative to the earlier packaging bag B, and allows the forward stack of packaging bags Cf to be fed to the reversing unit 12 without the front end of the packaging bag B lifting up.

[0026] As shown in Figure 4, the forward-facing stack of packaging bags Cf that reaches the reversing section 12 is first placed on the peripheral wall surface of the reversing drum 25, and as the reversing drum 25 rotates, it moves into the reversing path R formed between the peripheral wall surface of the reversing drum 25 and the reversing belt 26. As the forward-moving packaging bag stacking row Cf travels along the reversal path R, it is inverted vertically as it travels approximately half a turn along the peripheral wall of the reversal drum 25, transforming into a reverse-direction packaging bag stacking row Cr, where the later packaging bag B overlaps the earlier packaging bag B, as shown in Figure 4. Here, if the reversing drum drive unit 27 and the reversing belt drive unit 28 are controlled so that the rotational speed of the reversing drum 25 and the travel speed of the reversing belt 26 are the same, the overlap length between the latter half of the first packaging bag B and the first half of the second packaging bag B remains unchanged on the reversal path R, and the packaging bag stacking row Cf in the forward direction is reversed to the packaging bag stacking row Cr in the reverse direction. Next, when the reversing drum drive unit 27 and the reversing belt drive unit 28 are controlled so that the travel speed of the reversing belt 26 is faster than the rotation speed of the reversing drum 25, the front half of the later packaging bag B, which is stacked on top of the earlier packaging bag B, is moved closer to the earlier packaging bag B on the reversing path R as the reversing belt 26 travels. This makes it possible to increase the overlap length and increase the number of packaging bags included per unit length of the overlapping row of packaging bags C. Furthermore, when the reversing drum drive unit 27 and the reversing belt drive unit 28 are controlled so that the travel speed of the reversing belt 26 is slower than the rotation speed of the reversing drum 25, the front half of the later packaging bag B, which is stacked on top of the earlier packaging bag B, is delayed relative to the earlier packaging bag B on the reversing path R as the reversing belt 26 travels. This makes it possible to shorten the overlap length and reduce the number of packaging bags contained per unit length of the overlapping row C of packaging bags. As described above, in the forward-facing stack of packaging bags Cf, the later packaging bag B, which is stacked on top of the earlier packaging bag B, can be reversed to the reverse-facing stack of packaging bags Cr by changing the overlap length by changing the running speed of the reversing belt 26 relative to the rotation speed of the reversing drum 25. A similar effect can also be obtained by changing the rotation speed of the reversing drum 25 relative to the running speed of the reversing belt 26.

[0027] As described above, the overlapping rows of packaging bags Cf formed by being drawn out by the supply conveyor 11 have their overlap length determined by the frictional force between the overlapping packaging bags, as well as the weight of the bundle of packaging bags in the packaging bag stocker 100. When there are many heavy bundles of packaging bags, the subsequent packaging bag B, which is sandwiched between the bundle of packaging bags and the preceding packaging bag B, becomes difficult to pull out, and the overlap length of the subsequent packaging bag B relative to the preceding packaging bag B becomes shorter. On the other hand, when the number of packaging bags is small and light, the subsequent packaging bag B, which is sandwiched between the packaging bag bundle and the previous packaging bag B, becomes easier to pull out, so the overlap length of the subsequent packaging bag B relative to the previous packaging bag B becomes longer. Based on this, for example, a counting counter that counts how many packaging bags B have been pulled out from the bundle of packaging bags in the packaging bag stocker 100, or a weight counter that measures the weight of the bundle of packaging bags at the starting end of the supply conveyor 11, can be installed. By adjusting the running speed of the reversing belt 26 to be relatively slower or faster than the rotation speed of the reversing drum 25 according to the remaining amount of the bundle of packaging bags, the overlap length can be adjusted to optimally control the overlap of the stacks of packaging bags in accordance with a certain timing at which the bag feeding device delivers the packaging bags to the conveying path of the packaging machine.

[0028] Alternatively, an image sensor may be installed on the supply conveyor 11 to capture images of predetermined measurement points set on the packaging bags B, for example, detected by the image sensor. The amount of overlap and misalignment of the packaging bags B pulled out by the supply belt 15 from the packaging bag stocker 100 may then be fed back to the control unit. This allows the control unit to control the reversing belt drive unit 28 as needed when the overlap lengths of the preceding packaging bag B and the following packaging bag B detected by the image sensor are different, thereby changing the speed of the reversing belt 26 and forming a reverse-direction stack of packaging bags Cr on the reversing path R with overlap lengths equalized to a predetermined length. As will be described later, this is effective when the bag feeding arm 120 is operated at high speed to increase the bag feeding speed per unit time to the gripper device 130, by reducing the distance between the preceding and following packaging bags and increasing the number of packaging bags processed per unit time in accordance with the processing timing of the bag feeding arm.

[0029] The packaging bags B, which have been inverted to the reverse direction packaging bag stacking row Cr, are transferred to the discharge conveyor 13 connected to the inversion path R and transported on the discharge belt 35. Subsequently, as shown in Figure 5, the reverse direction packaging bag stacking row Cr is transferred from the discharge conveyor 13 to the bag supply conveyor 110 of the bag supply device. As shown in Figure 5, in the reverse direction, the stack of overlapping packaging bags Cr is placed on the bag conveyor 110 with the later packaging bag B overlapping the earlier packaging bag B. When the leading packaging bag B0 of the stack of overlapping packaging bags Cr reaches near the end of the bag conveyor 110, the area near the opening of the packaging bag B0 is attracted by a suction cup 120a and lifted by the bag feeding arm 120 with the opening facing upwards. It is then handed over to the gripper device 130 moving along the transport path of the packaging machine. In this way, the bag-feeding device can sequentially feed bags to the gripper device 130 using the bag-feeding arm 120, starting with the first bag B0 that has reached the front of the stacked row Cr of the reverse-direction bags.

[0030] According to the bag reversal device 10 of this embodiment, the packaging bags are sequentially pulled out from the bottommost packaging bag B of the stack of packaging bags piled up in the packaging bag stocker 100 to form a forward-facing stack of packaging bags Cf, and then the bags are reversed vertically in the reversal path R to form a reverse-facing stack of packaging bags Cr. Here, the leading packaging bag B0 in the reverse-direction stacking row Cr overlaps with the following packaging bag B, and as shown in Figure 5, the entire packaging bag is exposed. Therefore, when the bag-feeding arm 120 lifts the leading packaging bag B0, there is very little chance that the following packaging bag B will create resistance. As a result, after the leading packaging bag B0 is attached to the suction cup 120a, it can be smoothly lifted by the bag-feeding arm 120.

[0031] In the conventional case where packaging bags B were stocked one by one on the bag conveyor 110 without overlapping them and then lifted sequentially by the bag arm 120, if the forward stacking row of packaging bags Cf is placed directly on the bag conveyor 110, and the reciprocating motion of the bag arm 120 is relatively slow, the bag can be lifted by the bag arm 120 without much problem, even if a later packaging bag B overlaps the earliest packaging bag B0, except in special circumstances such as the packaging bags B sticking together due to static electricity. However, if the packaging efficiency per unit time of the packaging machine is increased and the gripper device 130 is configured to move at high speed along the conveying path, the reciprocating motion of the bag-feeding arm 120 that supplies packaging bags B to the gripper device 130 will also increase. In this case, if the overlap length of the packaging bag overlapping row C is set to be longer in synchronization with the high-speed reciprocating motion of the bag-feeding arm 120, the forward-facing packaging bag overlapping row Cf is formed in a direction opposite to the reverse-facing packaging bag overlapping row Cr shown in Figure 5, with the vicinity of the opening of the preceding packaging bag B slightly exposed from the front end of the following packaging bag B, in line with the direction of travel of the bag-feeding conveyor 110. Under these circumstances, if a forward-facing stack of packaging bags Cf, in which a later packaging bag B is stacked on top of a earlier packaging bag B, is placed on the bag-feeding conveyor 110, there is a risk that when the earlier packaging bag B is lifted, the overlapping later packaging bag B may move together with it due to static electricity, friction, etc. If such movement occurs, errors are more likely to occur in the process of the bag-feeding arm 120 picking up the packaging bag B with its suction cup 120a.

[0032] In contrast, with the bag reversal device 10 according to this embodiment, as shown in Figure 5, even if the overlap length between the first packaging bag B and the second packaging bag B is increased, and the rear end of the second packaging bag B exposed from the first packaging bag B is shortened, thereby increasing the number of packaging bags B per unit distance, the first packaging bag B0 in the reverse direction of the overlapping row of packaging bags Cr is superimposed on the top end of the overlapping row of packaging bags Cr, and the entire packaging bag is exposed. As a result, when the bag feeding arm 120 picks up the first packaging bag B0, it can be easily picked up, and furthermore, the second packaging bag B does not obstruct the feeding of the first packaging bag B, thereby improving the efficiency of the bag feeding process and making it easy to handle even when the gripper device 130 is moving at high speed due to the high speed of the packaging machine. [Explanation of Symbols]

[0033] 10...Bag inversion device, 11... Supply conveyor, 12... Reversing section, 13... Discharge conveyor, 15... Supply belt, 16... Supply belt drive unit, 17... Main supply rotor, 18... Subordinate supply rotor, 19... Supply tensioner 20...feeding mechanism, 21...feeding rotor, 22...feeding rotor drive unit, 25... Reversing drum, 26... Reversing belt, 27... Reversing drum drive unit, 28... Reversing belt drive unit, 29... Tension adjustment mechanism 30... Reversing main rotor, 31... Reversing trailing rotor, 32... Reversing belt motor, 33...Tension roller, 34...Guide groove, 35... Exhaust belt, 36... Exhaust belt drive unit, 100... Packaging bag dispenser, 110...Bag feeding conveyor, 120...Bag feeding arm, 120a...Suction cup 130... Gripper device, B...Packaging bag, B0...First packaging bag, C...Packaging bag polymerization sequence, Cf...Packaging bag polymerization sequence in the forward direction, Cr...Packaging bag polymerization sequence in the reverse direction R... Reversal path.

Claims

1. A supply conveyor having its starting point on the side of a packaging bag stocker where multiple packaging bags are stacked and stored, and equipped with a supply belt that continuously draws out one packaging bag at a time from the bottommost packaging bag stocked in the packaging bag stocker, The supply conveyor comprises a cylindrical reversing drum connected to the end of the supply conveyor and rotating at a predetermined rotational speed, a reversing drum drive unit that rotates the reversing drum at a predetermined rotational speed, a reversing belt positioned opposite the peripheral wall surface of the reversing drum and continuously running while being biased toward the peripheral wall surface, a reversing belt drive unit that runs the reversing belt at a predetermined belt speed, and a control unit that independently controls the reversing drum drive unit and the reversing belt drive unit, respectively, and a reversing unit that sandwiches the packaging bag between the peripheral wall surface and the belt surface of the reversing belt to reverse the front and back of the packaging bag, It consists of a discharge conveyor equipped with a discharge belt that continuously discharges the packaging bags that have been reversed after passing through the reversing section, The supply conveyor overlaps the front portion of a later-pulled-out packaging bag onto the rear portion of a later-pulled-out packaging bag, along the direction of travel of the supply belt, thereby forming a forward-facing overlapping row of packaging bags in which multiple packaging bags are arranged in a row with parts of each other overlapping. The reversing unit sandwiches the forward-facing stack of packaging bags between the peripheral wall surface and the belt surface and rotates it approximately halfway along the reversing drum, reversing it into a reverse-facing stack of packaging bags where the front half portion of the later packaging bags overlaps the rear half portion of the earlier packaging bags, and the control unit changes the belt speed of the reversing belt driven by the reversing belt drive unit relative to the rotational speed of the reversing drum driven by the reversing drum drive unit. The overlap length between the leading packaging bag and the trailing packaging bag in the aforementioned stacking row of packaging bags is adjusted. A bag reversal device characterized in that the discharge conveyor discharges the stacked rows of packaging bags in the reverse direction using the discharge belt.

2. A plurality of reversing rollers are provided, each consisting of a main reversing roller that supports the reversing belt and at least one dependent reversing roller that supports the reversing belt and moves in accordance with the main reversing roller. The bag reversing device according to claim 1, characterized in that the reversing belt consists of a plurality of round belts arranged at equal intervals along the axial direction of the reversing roller.

3. The bag reversing device according to claim 1, further characterized in that the reversing section is provided with a tension adjustment mechanism that adjusts the tension of the reversing belt to adjust the pressure at which the stacked packaging bags are sandwiched between the reversing belt and the reversing drum.

4. The bag reversing device according to claim 1, characterized in that the supply conveyor is provided with a dispensing mechanism that dispenses the packaging bags drawn out from the packaging bag stocker toward the reversing section and forms a forward stack of the packaging bags.

Images