Sheet overlapping device and bag making machine

Abstract

The sheet overlapping device uses a first slitter to slit a first main sheet into a first outer main body sheet and a second outer main body sheet. The overlapping device uses a second slitter to slit the second main sheet into a first inner main body sheet and a second inner main body sheet. The overlapping device guides the first and second outer body sheets to the pair of overlapping rollers. The overlapping device separates the first and second outer body sheets from each other and provides a space between the first and second outer body sheets until the first and second outer body sheets reach the overlapping roller pair. The overlapping device guides the first and second inner main body sheets to the pair of overlapping rollers through the space, so that the four sheets are overlapped with each other at the pair of overlapping rollers.

Description

Technical Field

[0001] The present application relates to a sheet overlapping device for a bag-making machine for successively manufacturing double bags. In addition, the present application relates to a bag-making machine for successively manufacturing double bags. Background Art

[0002] Double bags are widely known, for example, as disclosed in Patent Documents 1 and 2. The double bag includes at least two composite sheets facing each other. A storage space is formed between them by the two composite sheets. Each composite sheet is composed of an inner main body portion and an outer main body portion that are superposed on each other. Therefore, the double bag is composed of two inner main body portions and two outer main body portions, that is, at least four sheets.

[0003] Patent Document 1 also discloses a bag-making machine for successively manufacturing double bags. Such a bag-making machine unwinds sheets from four blank rolls provided at the uppermost stream of the bag-making machine. Two blank rolls are for the outer main body portion, and the remaining two blank rolls are for the inner main body portion. A sheet overlapping device composed of guide rollers, overlapping rollers, etc. is provided in the bag-making machine, and the four sheets unwound from the blank rolls are superposed on each other. The superposed sheets are fed to a processing device such as a heat-sealing device and processed.

[0004] As in Patent Document 1, in order to manufacture a double bag, four blank rolls are required. Due to minute differences in the feeding speed and winding amount of the four blank rolls, the timing when the four blank rolls are exhausted may deviate subtly. If this deviation accumulates, the timing for replacing the four blank rolls may deviate, and as a result, the man-hours for replacing the blank rolls may increase.

[0005] Prior Art Documents

[0006] Patent Documents

[0007] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2016-141427

[0008] Patent Document 2: Japanese Unexamined Patent Application Publication No. 2022-7011 Summary of the Invention

[0009] In the present application, there is provided a sheet overlapping device for a bag-making machine configured to successively manufacture double bags. The double bag includes a first outer main body portion, a second outer main body portion, a first inner main body portion, and a second inner main body portion, and the first inner main body portion and the second inner main body portion face each other and are sandwiched between the first outer main body portion and the second outer main body portion.

[0010] The sheet overlapping device includes:

[0011] A first slitter that, when a first main sheet unwound from a first blank roll is fed, slits the first main sheet into a first outer main body sheet for the first outer main body portion and a second outer main body sheet for the second outer main body portion;

[0012] A second slitter that, when a second main sheet unwound from a second blank roll is fed, slits the second main sheet into a first inner main body sheet for the first inner main body portion and a second inner main body sheet for the second inner main body portion;

[0013] An overlapping roll pair;

[0014] A first guiding mechanism that guides the first main sheet to the first slitter, guides the first outer main body sheet and the second outer main body sheet to the overlapping roll pair, and separates the first outer main body sheet from the second outer main body sheet to form a space between the first outer main body sheet and the second outer main body sheet until the first outer main body sheet and the second outer main body sheet reach the overlapping roll pair; and

[0015] A second guiding mechanism that guides the second main sheet to the second slitter, guides the first inner main body sheet and the second inner main body sheet from the space to the overlapping roll pair, and causes the first outer main body sheet, the second outer main body sheet, the first inner main body sheet, and the second inner main body sheet to overlap each other at the overlapping roll pair.

[0016] It may be that the overlapping roll pair is disposed at an interval from the first blank roll and the second blank roll in the forward horizontal direction.

[0017] It may be that the first guiding mechanism includes:

[0018] A first separating and guiding member that redirects the first outer main body sheet from a lateral upward direction perpendicular to the forward horizontal direction and redirects the second outer main body sheet from the lateral downward direction;

[0019] A first downstream horizontal roll that is disposed downstream of the first separating and guiding member and redirects the first outer main body sheet from an upward direction to the forward horizontal direction; and

[0020] A second downstream horizontal roll that is disposed downstream of the first separating and guiding member and redirects the second outer main body sheet from a downward direction to the forward horizontal direction.

[0021] It may be that the second guiding mechanism includes:

[0022] A second separating and guiding member for redirecting the first inner body sheet in the upward lateral direction and redirecting the second inner body sheet in the downward lateral direction;

[0023] A third downstream horizontal roller disposed downstream of the second separating and guiding member and configured to redirect the first inner body sheet from the upward direction to the forward horizontal direction; and

[0024] A fourth downstream horizontal roller disposed downstream of the second separating and guiding member and configured to redirect the second inner body sheet from the downward direction to the forward horizontal direction.

[0025] Optionally, the second cutter and the second separating and guiding member are spaced apart from the first separating and guiding member in the forward horizontal direction and are located below the first downstream horizontal roller and above the second downstream horizontal roller.

[0026] Optionally, the third downstream horizontal roller and the fourth downstream horizontal roller are spaced apart from the first separating and guiding member in the forward horizontal direction and are located below the first downstream horizontal roller and above the second downstream horizontal roller.

[0027] Optionally, the second guiding mechanism further includes a plurality of deflecting rollers for deflecting the second main sheet laterally from the first cutter and the first separating and guiding member.

[0028] Optionally, the first guiding mechanism further includes a first downstream vertical roller for redirecting the first main sheet from the forward horizontal direction to the lateral direction so that the first main sheet leads to the first cutter. Optionally, the first cutter is configured to cut the first main sheet fed laterally after passing through the first downstream vertical roller.

[0029] Optionally, the second guiding mechanism further includes a second downstream vertical roller for redirecting the second main sheet from the forward horizontal direction to the lateral direction so that the second main sheet leads to the second cutter. Optionally, the second cutter is configured to cut the second main sheet fed laterally after passing through the second downstream vertical roller.

[0030] It is possible that the first guiding mechanism and the second guiding mechanism are configured to guide the first outer main body sheet, the second outer main body sheet, the first inner main body sheet, and the second inner main body sheet in such a manner that all the edges of the first outer main body sheet, the second outer main body sheet, the first inner main body sheet, and the second inner main body sheet generated by slitting face the same direction when the first outer main body sheet, the second outer main body sheet, the first inner main body sheet, and the second inner main body sheet are stacked.

[0031] In the present application, a bag-making machine for successively manufacturing double bags is also provided. The bag-making machine includes the above-described sheet overlapping device.

[0032] It is possible that the bag-making machine further includes:

[0033] A feeding device, which is provided downstream of the overlapping roller pair and intermittently feeds the first outer main body sheet, the second outer main body sheet, the first inner main body sheet, and the second inner main body sheet;

[0034] A first tension adjusting roller, which is used to engage with the first outer main body sheet upstream of the overlapping roller pair to switch the feeding of the first outer main body sheet from continuous feeding to intermittent feeding;

[0035] A second tension adjusting roller, which is used to engage with the second outer main body sheet upstream of the overlapping roller pair to switch the feeding of the second outer main body sheet from continuous feeding to intermittent feeding;

[0036] A first link mechanism, which is used to interlock the first tension adjusting roller and the second tension adjusting roller; and

[0037] A first biasing member, which is used to bias the first tension adjusting roller and the second tension adjusting roller toward the first outer main body sheet and the second outer main body sheet respectively via the first link mechanism.

[0038] It is possible that the bag-making machine further includes:

[0039] A third tension adjusting roller, which is used to engage with the first inner main body sheet upstream of the overlapping roller pair to switch the feeding of the first inner main body sheet from continuous feeding to intermittent feeding;

[0040] A fourth tension adjusting roller, which is used to engage with the second inner main body sheet upstream of the overlapping roller pair to switch the feeding of the second inner main body sheet from continuous feeding to intermittent feeding;

[0041] A second link mechanism, which is used to interlock the third tension adjusting roller and the fourth tension adjusting roller; and

[0042] A second biasing member that biases the third and fourth tension adjusting rollers toward the first and second inner body sheets, respectively, via the second link mechanism.

[0043] The bag-making machine may further include:

[0044] A feeding device disposed downstream of the overlapping roller pair and intermittently feeding the first outer body sheet, the second outer body sheet, the first inner body sheet, and the second inner body sheet;

[0045] A sealing device disposed downstream of the overlapping roller pair and heat-sealing the first outer body sheet, the second outer body sheet, the first inner body sheet, and the second inner body sheet; and

[0046] A cross-cutting device disposed downstream of the sealing device and cross-cutting the first outer body sheet, the second outer body sheet, the first inner body sheet, and the second inner body sheet in the width direction each time intermittent feeding is performed to form the double bag. Description of the Drawings

[0047] Figure 1A Showing an exemplary double bag, Figure 1B is Figure 1A a partial cross-sectional view of the bag.

[0048] Figure 2A is a schematic top view of the upstream portion of an exemplary bag-making machine, Figure 2B and is a side view thereof.

[0049] Figure 3 is Figure 2A a schematic side view of the downstream portion of the bag-making machine.

[0050] Figure 4A 、 Figure 4B Showing an exemplary storage tank.

[0051] Figure 5 is a schematic side view of an exemplary overlapping device.

[0052] Figure 6 Showing Figure 5 views taken in the directions A-A, B-B, C-C, and D-D of.

[0053] Figure 7 is Figure 5 a top view of.

[0054] Figure 8A Exemplifying a structure for adjusting the position of the first main sheet, Figure 8B is Figure 8A an enlarged view of region T of.Figure 8C Illustrative inclined plate Figure 8D Shows Figure 8C The enlarged cross-section of S-S Figure 8E Illustrates the structure for adjusting the position of the second main sheet

[0055] Figure 9A Illustrates another structure for position adjustment Figure 9B Is Figure 9A The enlarged view of area T

[0056] Figure 10 Illustrates the structure for interlocking the tension adjusting roller

[0057] Figure 11 Illustrates the structure for reducing the swing amplitude of the arm of the link mechanism

[0058] Figure 12A Is the schematic top view of the other illustrative overlapping device Figure 12B Is its side view

[0059] Figure 13 Shows Figure 12B The views in the directions of A-A, B-B, C-C, and D-D

[0060] Figure 14A Is the schematic top view of the other illustrative overlapping device Figure 14B Is its side view

[0061] Figure 15 Shows Figure 14B The views in the directions of A-A, B-B, C-C, and D-D

[0062] Figure 16A Is the schematic top view of the other illustrative overlapping device Figure 16B Is its side view

[0063] Figure 17 Shows Figure 16B The views in the directions of A-A, B-B, C-C, and D-D Detailed implementation mode

[0064] Hereinafter, the implementation mode of the present application will be described with reference to the drawings. The following is merely an illustration of the present application. The drawings are merely schematic drawings, and there are cases where they are not drawn in correct dimensions. In addition, it should be understood that the same or similar components are denoted by the same reference numerals throughout the drawings

[0065] Figure 1A Shows the illustrative bag 1. The bag 1 includes the composite sheet 10 facing each other. As Figure 1BAs in the partial cross-sectional view, each composite sheet 10 is composed of an outer main body portion 11 and an inner main body portion 12 that are superposed on each other. The bag 1 has a first sealing portion 13 formed along both side edges of the bag 1 and a second sealing portion 14 formed along the upper and lower edges of the bag 1. In addition, the bag 1 has a mouth 15 assembled to one of the composite sheets 10. The content can be filled into the accommodation space between the two composite sheets 10 or taken out from the accommodation space through the mouth 15.

[0066] Figure 2A , Figure 2B Schematically shows the upstream part of a bag-making machine for successively manufacturing the bag 1 of FIG. 1. Two blank rolls 2' and 3' are provided. One blank roll 2' is wound with a first main sheet 2 for the outer main body portion 11 described above. The other blank roll 3' is wound with a second main sheet 3 for the inner main body portion 12 described above. In this illustration, the blank roll 2' is arranged on the lower side and the blank roll 3' is arranged on the upper side. The direction X1 is the forward horizontal direction of the sheet, and the direction X2 is the direction opposite to X1. The directions Y1 and Y2 are horizontal directions perpendicular to the direction X1 and are lateral. Y1 is set as the first lateral direction and the direction Y2 is set as the second lateral direction. Z1 is the upward direction and Z2 is the downward direction.

[0067] The sheet 2 is, for example, a laminated structure. One surface layer (base material layer) of the sheet 2 has a higher melting point than the other surface layer (sealing layer). The sheet 3 may be a raw material with a melting point lower than that of the base material layer of the sheet 2. Other characteristics (such as thickness) of the sheets 2 and 3 are determined according to the characteristics of the bag 1 to be manufactured (such as the strength of the bag, etc.). This is the same as in Patent Document 1.

[0068] The sheets 2 and 3 are respectively unwound from the blank rolls 2' and 3', continuously fed at a prescribed speed in the longitudinal direction of their long sides, and pass through the storage 80.

[0069] The storage 80 has a function of temporarily storing the sheets 2 and 3 for a certain length. In Figure 4A the illustrated storage 80, a group 801 of fixed rollers and a group 802 of movable rollers are respectively provided for the sheets 2 and 3. The sheets 2 and 3 are respectively alternately engaged with the fixed rollers and the movable rollers. The storage 80, as Figure 4A , Figure 4B shown, adjusts the storage amount by moving the group 802 of movable rollers closer to and farther from the group 801 of fixed rollers by using an actuator (not shown). Figure 4A Shows the case when the storage amount is larger. Figure 4B Shows the case when the storage amount is smaller.

[0070] When the winding amount of the blank roll decreases, the operator replaces the blank roll with a new one. During the replacement with a new blank roll, the sheet is not fed to the storage 80. During this period, the storage 80 feeds the stored sheet downstream. The operator completes the replacement of the sheet before the storage amount becomes zero. After that, the storage 80 increases the storage amount while increasing the unwinding speed of the sheet from the blank roll. Thus, even during the replacement operation of the blank roll, the sheet can be continuously fed to the devices arranged downstream, and the bag-making process can continue.

[0071] The bag-making machine also has Figure 2B a sheet overlapping device 4 as follows. The overlapping device 4 cuts the first main sheet 2 (unwound from the first blank roll 2') along its long side direction to divide it into two outer main sheets 20a and 20b, and cuts the sheet 3 (unwound from the second blank roll 3') along its long side direction to divide it into two inner main sheets 30a and 30b. This structure will be described in detail later.

[0072] The bag-making machine also has tension adjustment rollers 70a - 71b provided respectively for the four sheets 20a - 30b, and the tension adjustment rollers 70a, 70b / 71a, 71b are used to switch the feeding of the sheets 20a, 20b / 30a, 30b from continuous feeding to intermittent feeding. Therefore, at a position downstream of the tension adjustment rollers 70a, 70b, 71a, 71b, the sheets 20a - 30b are fed and temporarily stopped repeatedly.

[0073] The overlapping device 4 has an overlapping roll pair 40 at a position separated from the blank rolls 2', 3' in the forward horizontal direction X1. The overlapping device 4 guides the four sheets 20a - 30b to the overlapping roll pair 40 after the four sheets 20a - 30b pass through the tension adjustment rollers 70a - 71b, and makes the four sheets 20a - 30b pass through the overlapping roll pair 40. At this time, the overlapping device 4 makes the four sheets 20a - 30b overlap each other at the overlapping roll pair 40. The overlapping order is, from above, the outer main sheet 20a, the inner main sheet 30a, the inner main sheet 30b, and the outer main sheet 20b. Here, the outer main sheet 20a contacts the inner main sheet 30a with the high melting point surface layer (base material layer) facing the upper direction Z1 and the low melting point surface layer (sealing layer) facing the lower direction Z2. The outer main sheet 20b contacts the inner main sheet 30b with the high melting point surface layer facing the lower direction Z2 and the low melting point surface layer facing the upper direction Z1. The structure for this will also be described in detail later.

[0074] Figure 3 Schematically shows Figure 2A 、 Figure 2BThe downstream part of the bag-making machine. The bag-making machine also includes at least one feeding device 84 provided downstream of the overlapping roller pair 40. The feeding device 84 includes, for example, a driving roller pair and a servo motor. When the driving roller pair is intermittently rotated by the servo motor, the sheet materials 20a - 30b clamped by the driving roller pair are intermittently fed. Its conveying direction is shown by X1.

[0075] The bag-making machine also includes a nozzle assembly device 81 provided downstream of the overlapping roller pair 40. The nozzle assembly device 81 includes a plurality of guide rollers 810 and temporarily divides the four overlapping sheet materials 20a - 30b into two sheet materials 20a, 30a (forming one composite sheet 10) and two sheet materials 20b, 30b (forming the other composite sheet 10). And, in this separation interval, the nozzle assembly device 81 assembles the nozzles 15 on the sheet materials 20a, 30a every time there is intermittent feeding. For this purpose, the nozzle assembly device 81 includes a punching unit for punching holes in the sheet materials 20a, 30a, a sealing unit for inserting the nozzles 15 into the holes and sealing the sheet materials 20a, 30a, etc. Such a punching unit and sealing unit can have, for example, the same structure as these in Patent Document 1.

[0076] The bag-making machine also includes at least one heat-sealing device 82, 83 provided downstream of the overlapping roller pair 40. The heat-sealing devices 82, 83 heat-seal the sheet materials 20a - 30b with heat-sealing rods every time there is intermittent feeding. As described above, the low-melting-point surface layers of the sheet materials 20a, 20b are in contact with the low-melting-point inner main body sheet materials 30a, 30b respectively. Therefore, the inner main body sheet materials 30a, 30b are heat-sealed to each other and are also heat-sealed to the outer main body sheet materials 20a, 20b respectively. Thereby, the sealing portions 13, 14 of the bag 1 are formed.

[0077] The bag-making machine also includes a cross-cutting device 85 disposed at a position downstream of the heat-sealing devices 82, 83. The cross-cutting device 85 cross-cuts the four sheet materials 20a - 30b in the width direction with a cutter every time there is intermittent feeding. Every time there is cross-cutting, the bag 1 is formed. The two outer main body portions 11 are formed by the portions cut off from the outer main body sheet materials 20a, 20b through cross-cutting. The two inner main body portions 12 are formed by the portions cut off from the inner main body sheet materials 30a, 30b through cross-cutting. As described above, the double bag 1 is manufactured in sequence.

[0078] Hereinafter, with reference to Figure 5 、 Figure 6 、 Figure 7 the exemplary overlapping device 4 will be described. Figure 6 Summarize Figure 5 the A - A view, B - B view, C - C view, D - D view of

[0079] The main sheet 2 for the outer body is unwound from the blank roll 2', passes through the reservoir 80, and is fed in the forward horizontal direction X1 from the lower part of the reservoir 80. The inner body sheet 3 is unwound from the blank roll 3', passes through the reservoir 80, and is fed in the forward horizontal direction X1 from the upper part of the reservoir 80. In this illustration, the blank roll 2' for the outer body is wound with the sheet 2 having a high melting point surface layer (base material layer) facing outward.

[0080] The structure related to the sheet 2 is shown in Figure 5 the views taken along the B-B direction and the C-C direction (here, the sheets 3, 30a, and 30b are omitted). The overlapping device 4 includes a first cutter 41 for cutting the sheet 2 into the above two outer body sheets 20a and 20b when the sheet 2 is fed along its long side direction. In addition, the overlapping device 4 includes a first guiding mechanism 5 for guiding the sheet 2 in a manner that passes through the cutter 41 and guiding the sheets 20a and 20b to the overlapping roll pair 40.

[0081] The first guiding mechanism 5 includes a first upstream horizontal roll 50, a first inclined plate 51, a first upstream vertical roll 52, a first downstream vertical roll 53, a first separating and guiding member 54, and first and second downstream horizontal rolls 55 and 56.

[0082] The sheet 2 is directionally converted from the forward horizontal direction X1 to the upward direction Z1 by the upstream horizontal roll 50. Next, it is directionally converted to the second lateral direction Y2 by the triangular inclined plate 51, and then is directionally converted back to the forward horizontal direction X1 by the upstream vertical roll 52. That is, in Figure 6 the view taken along the B-B direction, the first guiding mechanism 5 converts the surface of the sheet 2 fed in the forward horizontal direction X1 from horizontal to vertical through these 50 - 52.

[0083] Thereafter, the sheet 2 is fed to the downstream vertical roll 53. The high melting point surface layer of the sheet 2 faces the second lateral direction Y2 in the interval between the roll 52 and the roll 53.

[0084] The sheet 2 passes through the downstream vertical roll 53, is converted from the forward horizontal direction X1 to the first lateral direction Y1, and leads to the cutter 41. At this time, the sheet 2 is cut by the cutter 41 along its long side direction at its central position and becomes the outer body sheets 20a and 20b. The sheets 20a and 20b are fed to the separating and guiding member 54.

[0085] The separating guide member 54 is a guide plate in an M shape formed by combining two triangular inclined plates. The outer main body sheet 20a is directionally converted from the first lateral direction Y1 upward in the Z1 direction by the separating guide member 54 and fed to the downstream horizontal roller 55. On the other hand, the outer main body sheet 20b is directionally converted from the first lateral direction Y1 downward in the Z2 direction by the separating guide member 54 and fed to the downstream horizontal roller 56. Further, the downstream horizontal roller 55 directionally converts the upper sheet 20a in the forward horizontal direction X1 and changes the surface of the sheet 20a from vertical to horizontal. The downstream horizontal roller 56 directionally converts the lower sheet 20b in the forward horizontal direction X1 and changes the surface of the sheet 20b from vertical to horizontal.

[0086] In this way, the first guiding mechanism 5 guides the sheet 2 to the slitter 41, separates the two sheets 20a and 20b vertically, and sets the surfaces of the sheets 20a and 20b to be horizontal. When passing through the downstream horizontal roller 55, the high melting point surface layer of the upper sheet 20a faces the upward direction Z1. When passing through the downstream horizontal roller 56, the high melting point surface layer of the lower sheet 20b faces the downward direction Z2.

[0087] Moreover, the first guiding mechanism 5 includes a plurality of guiding rollers 57 and a plurality of guiding rollers 58. An appropriate number of guiding rollers 57 / 58 are arranged between the downstream horizontal rollers 55 / 56 and the overlapping roller pair 40, and guide the sheets 20a / 20b to the overlapping roller pair 40 through the tension adjusting rollers 70a / 70b. Here, the first guiding mechanism 5 uses these rollers 55 - 58 to keep the sheets 20a and 20b separated from each other until the sheets 20a and 20b reach the overlapping roller pair 40, and forms a space 43 ( Figure 5 ) between the sheet 20a and the sheet 20b. This space 43 is effectively used to form the inner main body sheets 30a and 30b and guide them to the overlapping roller pair 40.

[0088] The structure related to the sheet 3 is shown in the A - A view and the D - D view of Figure 6 (here, the sheets 2, 20a, and 20b are omitted). The overlapping device 4 includes a second slitter 42 for slitting the sheet 3 into the above two inner main body sheets 30a and 30b when the sheet 3 is fed in its longitudinal direction. In addition, the overlapping device 4 includes a second guiding mechanism 6 for guiding the sheet 3 in such a way as to pass through the slitter 42 and guiding the sheets 30a and 30b from the space 43 to the overlapping roller pair 40.

[0089] The second guiding mechanism 6 includes a second upstream horizontal roller 60, a second inclined plate 61, a second upstream vertical roller 62, a second downstream vertical roller 63, a second separating guide member 64, third and fourth downstream horizontal rollers 65, 66, and middle vertical rollers 690, 691.

[0090] The sheet 3 is redirected from the advancing horizontal direction X1 to the downward direction Z2 by the upstream horizontal roller 60. Next, it is redirected to the first lateral direction Y1 by the inclined plate 61 in the shape of a triangle, and then redirected again to the advancing horizontal direction X1 by the upstream vertical roller 62. That is, in the A-A sectional view of Figure 6 , the second guiding mechanism 6 uses these rollers 60 - 62 to change the surface of the sheet 6 fed in the advancing horizontal direction X1 from horizontal to vertical.

[0091] After that, the sheet 3 is fed to the middle vertical roller 690 as Figure 7 . It is redirected to the second lateral direction Y2 by this roller 690, crosses between the two sheets 20a and 20b, moves toward the Y2 side, and is redirected to the advancing horizontal direction X1 by another middle vertical roller 691. And the sheet 3 is fed to the downstream vertical roller 63 with its surface in a vertical state. As Figure 7 , the sheet 3 detours from the first cutter 41 and the elements 50 - 56 of the first guiding mechanism 5 to the first lateral direction Y1 through the rollers 62 and 690. That is, the rollers 62 and 690 of the second guiding mechanism 6 constitute detour rollers.

[0092] After that, the sheet 3 is redirected from the advancing horizontal direction X1 to the first lateral direction Y1 by the downstream vertical roller 63 and then led to the cutter 42. At this time, the sheet 3 is cut by the cutter 42 along the long side direction at its central position and becomes the inner main body sheets 30a and 30b. The sheets 30a and 30b are fed to the separation guiding member 64.

[0093] The separation guiding member 64 is an M-shaped guiding plate identical to the separation guiding member 54. The inner main body sheet 30a is redirected from the first lateral direction Y1 to the upward direction Z1 by the separation guiding member 64 and fed to the downstream horizontal roller 65. On the other hand, the inner main body sheet 30b is redirected from the first lateral direction Y1 to the downward direction Z2 by the separation guiding member 64 and fed to the downstream horizontal roller 66. And the downstream horizontal roller 65 redirects the upper sheet 30a to the advancing horizontal direction X1 and changes the surface of the sheet 30a from vertical to horizontal. The downstream horizontal roller 66 redirects the lower sheet 30b to the advancing horizontal direction X1 and changes the surface of the sheet 30b from vertical to horizontal.

[0094] In this way, the second guiding mechanism 6 guides the sheet 3 to the cutter 42, separates the two sheets 30a and 30b vertically, and sets the surfaces of the sheets 30a and 30b to be horizontal.

[0095] Further, the second guiding mechanism 6 includes a plurality of guide rollers 67 and a plurality of guide rollers 68. An appropriate number of guide rollers 67 / 68 are provided between the downstream horizontal rollers 65 / 66 and the overlapping roller pair 40, and guide the sheets 30a / 30b to the overlapping roller pair 40 via the tension adjusting rollers 71a / 71b.

[0096] Therefore, the sheets 20a - 30b are superposed on each other at the overlapping roller pair 40. The order is, from above, the first outer main body sheet 20a, the first inner main body sheet 30a, the second inner main body sheet 30b, and the second outer main body sheet 20b. At this time, the low-melting-point surface layer of the outer main body sheet 20a contacts the inner main body sheet 30a, and the low-melting-point surface layer of the outer main body sheet 20b contacts the inner main body sheet 30b.

[0097] The second slitter 42, the second separation guiding member 64, the third and fourth downstream horizontal rollers 65, 66, and the guide rollers 67, 68 are arranged in the space 43 formed by the first guiding mechanism 5. That is, these elements 42, 64 - 68 are spaced apart from the first separation guiding member 54 in the forward horizontal direction X1, and are located below the first downstream horizontal roller 55 and above the second downstream horizontal roller 56. Thus, by arranging the second slitter 42 and the elements 64 - 68 of the second guiding mechanism 6 in the space 43 formed by the first guiding mechanism 5, the four sheets 20a - 30b formed from the two blank rolls 2', 3' can be superposed on each other.

[0098] As described above, the overlapping device 4 cuts the sheets 2, 3 released from the two blank rolls 2', 3' into four sheets 20a - 30b, and superposes these sheets 20a - 30b on each other at the overlapping roller pair 40. Therefore, the bag-making machine equipped with this overlapping device 4 can process (e.g., heat-seal) and transversely cut the four superposed sheets 20a - 30b at a position downstream of the overlapping roller pair 40, and thus can sequentially manufacture the double bag 1.

[0099] In the past, manufacturing a double bag required a total of four blank rolls, namely two blank rolls for the outer main body part and two blank rolls for the inner main body part. On the other hand, in the manufacturing of the double bag of the present application, due to the existence of the above-mentioned overlapping device 4, it is possible to use only a total of two blank rolls, namely one blank roll 2' for the outer main body part and one blank roll 3' for the inner main body part. This reduces the burden on the operator for the blank roll replacement operation and realizes the high efficiency of the operation. In addition, the reduction in the number of blank rolls from four to two can reduce the space required for setting the blank rolls, and contribute to the miniaturization of the bag-making machine as a whole.

[0100] In the above bag making, in order to perform the heat sealing process, it is necessary to bring the low melting point surface layers of the sheets 20a and 20b into contact with the sheets 30a and 30b at the overlapping roller pair 40. Therefore, when changing the direction of the sheets 2, 20a, and 20b using the elements of the first guiding mechanism 5, it is necessary to pay attention that there is also a change in the orientation of the high melting point surface layer / low melting point surface layer of the sheets 2, 20a, and 20b. In addition, it is also necessary to pay attention to whether the first blank roll 2' is wound with the high melting point surface layer of the first main sheet 2 facing outward or inward.

[0101] Different from the above examples, in the case where the sheets 2 and 3 are not laminates but single materials, a neutral ink (medium ink) that hinders heat sealing may sometimes be applied to one side. Thus, it is often the case that the back surface and the front surface of the sheets 2 and 3 are specified.

[0102] Therefore, the guiding mechanisms 5 and 6 may also have additional elements or have a structure different from the above examples. However, when performing bag making accompanied by heat sealing, it is necessary to pay full attention to the change of the surface of the sheet and the front and back surfaces of the sheet by the elements of the guiding mechanisms 5 and 6. Those skilled in the art can easily understand the above situation.

[0103] The illustrated main sheet 2 (outer main sheets 20a and 20b) has a base material layer and a sealing layer. The base material layer is generally stronger in terms of damage resistance and friction than the sealing layer. Therefore, when the sheets 2, 20a, or 20b generate frictional force with respect to the elements of the first guiding mechanism 5 such as the first inclined plate 51 and the first separating and guiding member 54 and are guided, it is preferable that the base material layer rather than the sealing layer is in frictional contact with these elements.

[0104] As Figure 6 seen in the C-C direction view and the D-D direction view, as a result of the slitting, edges 200a, 200b, 300a, and 300b are respectively generated in the sheets 20a - 30b. As Figure 7 shown, the first and second guiding mechanisms 5 and 6 direct all of the edges 200a, 200b, 300a, and 300b in the same direction (the second lateral direction Y2 in the embodiment) at the overlapping roller pair 40. And, as Figure 7 shown, when the first and second guiding mechanisms 5 and 6 cause the sheets 20a - 30b to overlap each other at the overlapping roller pair 40, they align these edges 200a - 300b with each other.

[0105] The linearity of the edges on both sides of the main sheets 2 and 3 is low due to the manufacturing process and handling process of the main sheets themselves. On the other hand, as in the embodiment, the linearity of the edges 200a - 300b of the sheets generated by slitting while being mechanically transported is high, and the passing positions of the edges are stable. Therefore, by accurately aligning the edges 200a - 300b, the accuracy of bag making (processing required for bag making) is improved.

[0106] An exemplary structure for this will be described below. As Figure 8A shown, the overlapping device 4 may also include a first position sensor 44 that detects the position of the sheet 2 in the width direction during feeding, and an actuator 45 for finely adjusting the tilting plate 51 up and down.

[0107] As Figure 8C shown, the tilting plate 51 has a tilting edge 510 for changing the direction of the sheet 2. The sheet 2 is folded back by engaging with the tilting edge 510, thereby changing the direction in a manner accompanied by the reversal of the orientation of the surface of the sheet 2. This tilting edge 510 has a rounded corner as in the Figure 8D S - S cross - section shown in order to prevent damage to the sheet 2 and the like. It should be noted that the tilting plates 61, separation guide members 54, 64 (M - shaped guide plates) also have the same tilting edge, whereby smooth direction change of the sheet accompanied by the reversal of the surface orientation can be achieved.

[0108] In this example, the position sensor 44 detects the height of the edge of the sheet 2 at the first upstream vertical roller 52 for the main sheet 2 (where the edge of the sheet 2 extends horizontally). Alternatively, the position sensor 44 can detect the position of the sheet 2 in the width direction by detecting a linear mark marked on the sheet 2 by means such as printing. The position sensor 44 is an optical sensor. The actuator 45 finely moves the tilting plate 51 up and down.

[0109] As is clear from Figure 8B the figure, when the tilting plate 51 descends, the sheet 2 after passing through the tilting edge 510 of the tilting plate 51 also descends (refer to the Figure 8B arrow in the figure). At this time, the height of the edge (linear mark) detected by the position sensor 44 also decreases. Similarly, when the tilting plate 51 ascends, the sheet 2 also ascends, and the height of the detected edge also increases. Therefore, the overlapping device 4 can finely adjust the sheet 2 in its width direction (the height of the sheet 2) by using the actuator 45 to finely move the tilting plate 51 up and down.

[0110] Downstream thereof, as described above, the sheet 2 is slit by the slitter 41 into two sheets 20a and 20b. Here, the slitter 41 is fixed. That is, the overlapping device 4 (one or more processors thereof) can finely adjust the positions of the edges 200a and 200b generated by slitting by finely adjusting the tilt plate 51 up and down by means of the actuator 45 based on the detection by the position sensor 44.

[0111] In addition, the overlapping device 4 may also be provided with a position sensor 46 and an actuator 47 for the main sheet 3 in the same manner, and can similarly finely adjust the positions of the edges 300a and 300b of the sheets 30a and 30b. Figure 8E In this illustration, the main sheets 2 and 3 are slit by the slitters 41 and 42 respectively after the fine adjustment of the edges. As a result, the edges on the Y1 side are detected by the position sensors 44 and 46. Therefore, the edges detected by the position sensors 44 and 46 can be aligned with high precision on the Y1 side after slitting.

[0112] Moreover, as described above, one edge of each of the main sheets 2 and 3 is detected by the position sensors 44 and 46 respectively. After the positions are finely adjusted by the actuators 45 and 47 based on the detection by the position sensors 44 and 46, the main sheets 2 and 3 are slit by the slitters 41 and 42 at the mechanically fixed positions. Therefore, after slitting, the edges 200a - 300b generated by slitting can also be aligned with high precision on the Y2 side.

[0113] Therefore, the overlapping device 4 can align the edges of the sheets 20a - 30b with high precision by this structure. As a result, high-precision bag making can be performed.

[0114] Although the edges on the Y1 side of the sheets 20a - 30b are finely adjusted, due to the deviation of the original total width dimensions of the main sheets 2 and 3, they may become slightly misaligned. Such a problem can be solved by slitting the sheets 20a - 30b along the edges on the Y1 side in a subsequent process. In addition, in the case where the finely adjusted edges 200a - 300b on the Y2 side may shift in position later, they can also be adjusted as needed by known means.

[0115] It should be noted that, as shown in, the separation guide member 64, which is a guide plate in the shape of an M, can also be moved in the lateral directions Y1 and Y2 by the actuator 47 to adjust the positions of the edges 300a and 300b (for example, refer to the arrow in). And although not shown in the figure, the separation guide member 54 (

[0116] It should be noted that, as shown in Figure 9A , Figure 9B the separation guide member 64, which is a guide plate in the shape of an M, can also be moved in the lateral directions Y1 and Y2 by the actuator 47 to adjust the positions of the edges 300a and 300b (for example, refer to the arrow in Figure 9B )). And although not shown in the figure, the separation guide member 54 ( Figure 6It moves in the lateral directions Y1 and Y2 (in the C-C direction view), thereby adjusting the positions of the edges 200a and 200b.

[0117] The bag-making machine is provided with a first tension adjusting roller 70a for engaging with the first outer main body sheet 20a, a second tension adjusting roller 70b for engaging with the second outer main body sheet 20b, a third tension adjusting roller 71a for engaging with the first inner main body sheet 30a, and a fourth tension adjusting roller 71b for engaging with the second inner main body sheet 30b as described above. And the bag-making machine uses these rollers 70a - 71b to switch the continuous feeding of these sheets 20a - 30b to intermittent feeding.

[0118] And the bag-making machine Figure 10 is provided with a first link mechanism 90 for interlocking the first and second tension adjusting rollers 70a and 70b, and a first biasing member 94 (e.g., a working cylinder) for biasing the first and second tension adjusting rollers 70a and 70b toward the sheets 20a and 20b respectively via the first link mechanism 90.

[0119] The first link mechanism 90 includes two arms 91a and 91b that are substantially L-shaped and have the same shape, each consisting of a short portion and a long portion. The arms 91a and 91b can each rotate about its bent portion by means of a rotating shaft 92a and 92b. The tension adjusting roller 70a is supported at the front end of the long portion of the arm 91a so as to be rotatable, and the tension adjusting roller 70b is supported at the front end of the long portion of the arm 91b so as to be rotatable. In addition, the front ends of the short portions of the two arms 91a and 91b are interconnected by a link 93. With this structure of the first link mechanism 90, the tension adjusting rollers 70a and 70b can move in the same direction by the same distance relative to each other.

[0120] In addition, the first biasing member 94 biases the arms 91a and 91b toward the first and second outer main body sheets 20a and 20b ( Figure 10 counterclockwise in the figure), thereby applying a tension force to the first and second outer main body sheets 20a and 20b.

[0121] For example, even if the upper outer main body sheet 20a engaged with the tension adjusting roller 70a becomes slack, the two arms 91a and 91b (and thus the tension adjusting rollers 70a and 70b) rotate in conjunction ( Figure 10 counterclockwise in the figure) due to the first biasing member 94, thereby forcibly stretching the lower outer main body sheet 20b and eliminating the slack of the outer main body sheet 20a. As a result, the path line lengths of the outer main body sheet 20a and the outer main body sheet 20b are the same as each other.

[0122] The sheets 20a and 20b are formed by cutting a main sheet 2, and are theoretically the same in length. However, in practice, due to the uneven thickness of the main sheet 2 in its width direction or the like, the path line lengths of the two may change during feeding. As described above, the link mechanism 90 and the biasing member 94 can keep the path line lengths of the two the same, and thus can solve this problem.

[0123] The bag-making machine includes a second link mechanism 95 for interlocking the third and fourth tension adjusting rollers 71a and 71b, and a second biasing member 99 (for example, a working cylinder) that biases the third and fourth tension adjusting rollers 71a and 71b toward the sheets 30a and 30b via the second link mechanism 95. The second link mechanism 95 includes arms 96a and 96b, rotating shafts 97a and 97b, and a link 98. The structures of the second link mechanism 95 and the second biasing member 99 are the same as those of the first link mechanism 90 and the first biasing member 94, so that the path line lengths of the two sheets 30a and 30b are the same.

[0124] As Figure 11 In the example of, the additional first tension adjusting roller 70c and the additional second tension adjusting roller 70d may also be rotatably supported by the arms 91a and 91b of the first link mechanism 90, respectively. The sheets 20a and 20b are wound in the order of the tension adjusting rollers 70a and 70b, one of the plurality of guide rollers 57 and 58 (the aforementioned guide rollers for guiding the sheets 20a and 20b to the overlapping roller pair 40) with fixed positions, and the additional tension adjusting rollers 70c and 70d. Thereby, the swing amplitude of the arms 91a and 91b can be reduced.

[0125] Similarly, the additional third tension adjusting roller 71c and the additional fourth tension adjusting roller 71d may also be rotatably supported by the arms 96a and 96b of the second link mechanism 95, respectively. The sheets 30a and 30b are wound in the order of the tension adjusting rollers 71a and 71b, one of the plurality of guide rollers 67 and 68 (the aforementioned guide rollers for guiding the sheets 30a and 30b to the overlapping roller pair 40) with fixed positions, the additional tension adjusting rollers 71c and 71d. Thereby, the swing amplitude of the arms 96a and 96b can be reduced.

[0126] Generally, a single material such as polyethylene or polypropylene has lower rigidity and higher stretchability than a laminated raw material. Therefore, in the case of using a sheet of a single material, the stretching range becomes larger when the swing amplitude of the tension adjusting roller is larger. When the sheets 20a, 20b / 30a, 30b are of a single material, due to such stretching, when the sheets 20a, 20b / 30a, 30b pass through the separating guide members 54 / 64 ( Figure 6When the frictional force generated at ( ) changes significantly, it may impede smooth transportation.

[0127] Figure 11 The structure can suppress the swing amplitude of the arms 91a, 91b / 96a, 96b, so it can suppress the change of the above-mentioned frictional force. As a result, smooth transportation of the sheets 20a, 20b / 30a, 30b is provided.

[0128] In addition, Figure 11 The structure can suppress the swing amplitude of the arms 91a, 91b, 96a, 96b even when the intermittent transportation pitch of the sheets 20a - 30b downstream of the tension adjustment rollers 70a - 71d is large. Thus, as a result, it is possible to suppress the change of the pulling stress applied to the sheets 20a - 30b, suppress the stretching and shrinking amplitude of the sheets 20a - 30b, and provide smoother transportation of the sheets 20a - 30b.

[0129] The arms 91a, 91b, 96a, 96b preferably have a small inertia, so they are preferably made of a light raw material such as carbon.

[0130] Hereinafter, other examples of the first and second guiding mechanisms 5 and 6 that can perform the above-mentioned bag making will be described below. The same reference numerals are assigned to the same or similar structures.

[0131] Figure 12A , Figure 12B , Figure 13 The overlapping device 4 showing other examples is shown. In this example, the middle-stream vertical rollers 690, 691 ( Figure 7 ) of the previously shown example are not provided. The downstream vertical roller 63 is not arranged on the Y2 side, but on the Y1 side. The upstream vertical roller 62 and the downstream vertical roller 63 function as bypass rollers, and cause the sheet 3 to bypass to the first lateral direction Y1 without interfering with the elements 50 - 56 of the slitter 41 and the first guiding mechanism 5. The sheet 3 changes its direction from the forward horizontal direction X1 to the second lateral direction Y2 through the downstream vertical roller 63, and leads to the slitter 42 ( Figure 13 in the D - D direction view of ). It should be noted that in this example, the edges 200a, 200b and the edges 300a, 300b are not aligned with each other at the overlapping roller pair 40.

[0132] Figure 14A , Figure 14B , Figure 15 Another example of the overlapping device 4 is shown. As Figure 15 in the A - A direction view of, the orientation of the inclined plate 61 in this example is the same as Figure 6The orientation in the A-A direction is opposite, and the main sheet 3 is redirected in the direction of the second lateral Y2. Moreover, neither the upstream vertical roller 62 nor the downstream vertical roller 63 is arranged on the Y1 side but on the Y2 side. Thus, a detour roller is formed that guides the sheet 3 to a position further outside than the sheet 2 and detours in the second lateral Y2 in a manner that does not interfere with the elements 50-56 of the slitter 41 and the first guiding mechanism 5, and guides it to the slitter 42.

[0133] Figure 16A , Figure 16B , Figure 17 An overlapping device 4 showing another exemplary case is shown. As Figure 16A , Figure 16B shown, this exemplary case is different from the above exemplary case. The blank roll 2' for the outer body is arranged on the upper side, and the blank roll 3' for the inner body is arranged on the lower side. Moreover, the blank roll 2' is wound with the main sheet 2 having the high-melting-point surface layer facing inward. The sheet 2 is redirected from the forward water direction X1 to the downward direction Z2 by the upstream horizontal roller 50, redirected in the direction of the second lateral Y2 by the inclined plate 51, and then redirected to the forward horizontal direction X1 by the upstream vertical roller 52 and fed to the downstream vertical roller 53. Thus, similarly to the above other exemplary cases, when the sheets 20a-30b are overlapped with each other at the overlapping roller pair 40, the low-melting-point surface layers of the sheets 20a and 20b can be brought into contact with the sheets 30a and 30b, respectively.

[0134] The overlapping device 4 is not limited to Figure 1A the manufacture of the simple double bag 1 and can be applied to the manufacture of all types of double bags. For example, it is obvious to those skilled in the art that the overlapping device 4 can be assembled into a bag-making machine for double bags that replaces the mouth 15 or further has additional elements such as chucks and gussets on this basis.

[0135] Explanation of reference numerals

[0136] 1 Double bag

[0137] 11 First and second outer body parts

[0138] 12 First and second inner body parts

[0139] 2 First main sheet

[0140] 2' First blank roll

[0141] 20a, 20b First and second outer body sheets

[0142] 3 Second main sheet

[0143] 3' Second blank roll

[0144] 30a, 30b First and second inner body sheets

[0145] 4-sheet overlapping device

[0146] 40 overlapping roll pairs

[0147] 41 First cutter

[0148] 42 Second cutter

[0149] 5 First guiding mechanism

[0150] 53 First downstream vertical roll

[0151] 54 First separation guiding member

[0152] 55 First downstream horizontal roll

[0153] 56 Second downstream horizontal roll

[0154] 6 Second guiding mechanism

[0155] 63 Second downstream vertical roll

[0156] 64 Second separation guiding member

[0157] 65 Third downstream horizontal roll

[0158] 66 Fourth downstream horizontal roll

[0159] 62, 63, 690 Deflection rolls

[0160] 70a, 70b, 71a, 71b First, second, third and fourth tension adjusting rolls

[0161] 82, 83 Sealing device

[0162] 84 Feeding device

[0163] 85 Cross-cutting device

[0164] 90 First link mechanism

[0165] 94 First biasing member

[0166] 95 Second link mechanism

[0167] 99 Second biasing member.

Claims

1. A sheet overlapping device, which is a sheet overlapping device for a bag-making machine configured to sequentially manufacture double bags, wherein, the double bag includes a first outer main body portion, a second outer main body portion, a first inner main body portion, and a second inner main body portion, and the first inner main body portion and the second inner main body portion are opposed to each other and sandwiched between the first outer main body portion and the second outer main body portion; the sheet overlapping device includes: a first cutter, which is used to cut the first main sheet unwound from the first blank roll into a first outer main sheet for the first outer main body portion and a second outer main sheet for the second outer main body portion when the first main sheet is fed; a second cutter, which is used to cut the second main sheet unwound from the second blank roll into a first inner main sheet for the first inner main body portion and a second inner main sheet for the second inner main body portion when the second main sheet is fed; an overlapping roll pair; a first guiding mechanism, which guides the first main sheet to the first cutter, and guides the first outer main sheet and the second outer main sheet to the overlapping roll pair, and the first guiding mechanism separates the first outer main sheet and the second outer main sheet from each other to form a space between the first outer main sheet and the second outer main sheet until the first outer main sheet and the second outer main sheet reach the overlapping roll pair; and a second guiding mechanism, which guides the second main sheet to the second cutter, and guides the first inner main sheet and the second inner main sheet from the space to the overlapping roll pair, so that the first outer main sheet, the second outer main sheet, the first inner main sheet, and the second inner main sheet are overlapped with each other at the overlapping roll pair.

2. The sheet overlapping device according to claim 1, wherein, the overlapping roll pair is arranged at a distance from the first blank roll and the second blank roll in the forward horizontal direction; the first guiding mechanism includes: a first separating and guiding member, which is used to change the direction of the first outer main sheet from the lateral upward direction perpendicular to the forward horizontal direction, and change the direction of the second outer main sheet from the lateral downward direction; a first downstream horizontal roll, which is arranged downstream of the first separating and guiding member and is used to change the direction of the first outer main sheet from the upper direction to the forward horizontal direction; and a second downstream horizontal roll, which is arranged downstream of the first separating and guiding member and is used to change the direction of the second outer main sheet from the lower direction to the forward horizontal direction; the second guiding mechanism includes: a second separating and guiding member, which is used to change the direction of the first inner main sheet from the lateral upward direction, and change the direction of the second inner main sheet from the lateral downward direction; a third downstream horizontal roll, which is arranged downstream of the second separating and guiding member and is used to change the direction of the first inner main sheet from the upper direction to the forward horizontal direction; and A fourth downstream horizontal roller, which is disposed downstream of the second separation guide member and is configured to change the direction of the second inner main sheet from below to the forward horizontal direction.

3. The sheet overlapping device according to claim 2, wherein the second cutter and the second separation guide member are spaced apart from the first separation guide member in the forward horizontal direction, and are located below the first downstream horizontal roller and above the second downstream horizontal roller.

4. The sheet overlapping device according to claim 3, wherein the third downstream horizontal roller and the fourth downstream horizontal roller are spaced apart from the first separation guide member in the forward horizontal direction, and are located below the first downstream horizontal roller and above the second downstream horizontal roller.

5. The sheet overlapping device according to claim 2, wherein the second guiding mechanism further includes a plurality of bypass rollers configured to bypass the second main sheet from the first cutter and the first separation guide member to the lateral direction.

6. The sheet overlapping device according to claim 2, wherein the first guiding mechanism further includes a first downstream vertical roller configured to change the direction of the first main sheet from the forward horizontal direction to the lateral direction so that the first main sheet leads to the first cutter, the first cutter is configured to cut the first main sheet fed laterally after passing through the first downstream vertical roller.

7. The sheet overlapping device according to claim 6, wherein the second guiding mechanism further includes a second downstream vertical roller configured to change the direction of the second main sheet from the forward horizontal direction to the lateral direction so that the second main sheet leads to the second cutter, the second cutter is configured to cut the second main sheet fed laterally after passing through the second downstream vertical roller.

8. The sheet overlapping device according to claim 1, wherein the first guiding mechanism and the second guiding mechanism are configured to guide the first outer main sheet, the second outer main sheet, the first inner main sheet, and the second inner main sheet in such a manner that all the edges of the first outer main sheet, the second outer main sheet, the first inner main sheet, and the second inner main sheet generated by cutting face the same direction when the first outer main sheet, the second outer main sheet, the first inner main sheet, and the second inner main sheet are overlapped.

9. A bag making machine for successively manufacturing double bags, wherein the bag making machine includes the sheet overlapping device according to claim 1.

10. The bag making machine according to claim 9, wherein the bag making machine further includes: a feeding device, which is disposed downstream of the overlapping roller pair and intermittently feeds the first outer main sheet, the second outer main sheet, the first inner main sheet, and the second inner main sheet; a first tension adjusting roller, which is engaged with the first outer main sheet upstream of the overlapping roller pair to switch the feeding of the first outer main sheet from continuous feeding to intermittent feeding; A second tension adjusting roller that engages with the second outer main body sheet upstream of the overlapping roller pair to switch the second outer main body sheet from continuous feeding to intermittent feeding; A first link mechanism that interlocks the first tension adjusting roller and the second tension adjusting roller with each other; And A first biasing member that biases the first tension adjusting roller and the second tension adjusting roller toward the first outer main body sheet and the second outer main body sheet, respectively, via the first link mechanism.

11. The bag-making machine according to claim 10, wherein The bag-making machine further includes: A third tension adjusting roller that engages with the first inner main body sheet upstream of the overlapping roller pair to switch the first inner main body sheet from continuous feeding to intermittent feeding; A fourth tension adjusting roller that engages with the second inner main body sheet upstream of the overlapping roller pair to switch the second inner main body sheet from continuous feeding to intermittent feeding; A second link mechanism that interlocks the third tension adjusting roller and the fourth tension adjusting roller with each other; And A second biasing member that biases the third tension adjusting roller and the fourth tension adjusting roller toward the first inner main body sheet and the second inner main body sheet, respectively, via the second link mechanism.

12. The bag-making machine according to claim 9, wherein The bag-making machine further includes: A feeding device that is provided downstream of the overlapping roller pair and intermittently feeds the first outer main body sheet, the second outer main body sheet, the first inner main body sheet, and the second inner main body sheet; A sealing device that is provided downstream of the overlapping roller pair and heat-seals the first outer main body sheet, the second outer main body sheet, the first inner main body sheet, and the second inner main body sheet; And A cross-cutting device that is provided downstream of the sealing device and cross-cuts the first outer main body sheet, the second outer main body sheet, the first inner main body sheet, and the second inner main body sheet in the width direction thereof each time intermittent feeding is performed, thereby forming the double bag.

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