JP2018015971A - Creased corrugated cardboard sheet manufacturing method and ruled line ring set - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a creased corrugated cardboard sheet manufacturing method capable of making difficult surface layer degradation or the like of a corrugated cardboard sheet when a forward ruled line and a backward ruled line are both formed on the corrugated cardboard sheet and using a common ruled line ring when an upper flat becomes an operation side and when the upper flat becomes a driving side.SOLUTION: A projected part 13 and recessed parts 14 on axial both sides of the projected part 13 are provided on the outer periphery of a first ruled line ring 7. A pair of grooves 15, a center mountain part 16, and a pair of groove shoulders 17 are provided on the outer periphery of a second ruled line ring 8. The outer diameter of the center mountain part 16 is set larger than that of the groove shoulder 17. A forward ruled line 20 is formed between the projected part 13 and the groove part 15, and simultaneously a backward ruled line 21 is formed between the center mountain part 16 and the recessed part 14.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a method for producing a corrugated cardboard sheet for producing a corrugated cardboard sheet having a normal ruled line and a reverse ruled line, and a ruled ring set used for the method for producing the corrugated cardboard sheet.

  Generally, a corrugated cardboard box has a peripheral wall formed by bending corrugated cardboard into a cylindrical shape, a plurality of upper flaps connected to the upper end of the peripheral wall, and a plurality of lower flaps connected to the lower end of the peripheral wall. A regular ruled line is formed between the upper flap and the peripheral wall, and between the lower flap and the peripheral wall. The regular ruled line is a ruled line in which the back liner side of the cardboard (that is, the inside of the box) is recessed. Then, the lid of the cardboard box is formed by folding the upper flap inside the peripheral wall along the regular ruled line between the upper flap and the peripheral wall, and the lower flap is arranged inside the peripheral wall along the regular ruled line between the lower flap and the peripheral wall. The bottom of the cardboard box is formed by folding it.

  When a product is packed in a cardboard box, the upper flap may be folded outside the peripheral wall (so-called reverse folding) in order to facilitate insertion of the product into the cardboard box. Here, since the regular ruled line between the upper flap and the peripheral wall has a concave shape on the back liner side, when the upper flap is folded inside the box, the upper flap can be smoothly folded along the regular ruled line, When folding the upper flap to the outside of the box, the upper flap is difficult to break. Therefore, after folding the upper flap to the outside of the box, it is necessary to hold the upper flap by hand so that the upper flap does not return elastically, or it is completely outside the box so that the upper flap does not return. When the upper flap is folded, the back liner of the cardboard is broken along the regular ruled line (so-called liner cracking).

  In order to solve such a problem, a cardboard box of Patent Document 1 has been proposed. In the corrugated cardboard box of Patent Document 1, a reverse ruled line extending in parallel with the regular ruled line is formed in addition to the conventional regular ruled line at the base portion of the upper flap. The reverse ruled line is a ruled line in which the front liner side (that is, the outside of the box) is recessed. When this reverse ruled line is provided, when the upper flap is folded to the outside of the peripheral wall, the upper flap is smoothly folded along the reverse ruled line, so that the product can be easily boxed.

Japanese Utility Model Publication No. 60-123317

  In general, when forming a regular ruled line on a corrugated cardboard sheet, the corrugated cardboard sheet running along the corrugator is sandwiched by a pair of ruled line rings from the front liner side and the back liner side, thereby extending the regular ruled line along the running direction of the cardboard sheet. Form. Similarly, with respect to the reverse ruled line, the reverse ruled line extending along the running direction of the cardboard sheet can be formed by sandwiching the cardboard sheet running by the corrugator between the pair of ruled line rings.

  Here, the inventor has a pair of ruled lines for forming a regular ruled line on the cardboard sheet and a pair of ruled rings for forming a reverse ruled line on the cardboard sheet, upstream and downstream in the running direction of the cardboard sheet. A test was conducted in-house in which a regular ruled line and a reverse ruled line at the base of the upper flap were formed in order by providing the cardboard sheets with the ruled line rings in order at a distance from the side.

  As a result, a pair of crease rings for forming a regular crease line on the cardboard sheet and a pair of crease rings for forming a reverse crease line on the cardboard sheet, the corrugator sequentially sandwiches the corrugated cardboard sheet and the upper flap When the regular ruled line and reverse ruled line of the base are formed, the part corresponding to the base of the upper flap is sandwiched twice by the ruled ring, which may cause deterioration of the surface layer of the corrugated cardboard at the base of the upper flap. , The front liner or back liner may peel off at the base of the upper flap, or when the upper flap is folded inside the box, the cardboard sheet may break at both the regular and reverse ruled lines (two-stage folding). It has been found that

  Therefore, in order to prevent the surface layer deterioration due to the same portion of the corrugated cardboard sheet being pinched twice, the inventor can insert both the regular ruled line and the reverse ruled line by simply pinching the cardboard sheet once as shown in FIG. The use of a pair of special ruled line rings 70 and 71 to be formed was examined. The special ruled line rings 70 and 71 form a normal ruled line with the upper male part 72 formed on the upper special ruled line ring 70 and the lower female part 73 formed on the lower special ruled line ring 71 and at the same time An upper female part 74 formed adjacent to the upper male part 72 on the special ruled line ring 70 and a lower male part 75 formed adjacent to the lower female part 73 on the lower special ruled line ring 71. A reverse ruled line is formed, and both the upper and lower special ruled line rings 70 and 71 have an asymmetric cross-sectional shape.

  However, when special ruled line rings 70 and 71 as shown in FIG. 14 are used, it has been found that there are the following problems.

  That is, in general, in a corrugator that manufactures a corrugated cardboard sheet, the cardboard sheet is manufactured in the direction in which the upper flap is on the operating side and the lower flap is on the driving side, and the opposite direction (that is, the upper flap is on the driving side and the lower flap is on the driving side). In some cases, the cardboard sheet is manufactured in the direction of the operation side. The operation side and drive side of the corrugator refer to one side and the other side in the horizontal direction orthogonal to the running direction of the cardboard sheet.

  Then, when a normal ruled line and a reverse ruled line between the upper flap and the peripheral wall are to be formed using the pair of special ruled line rings 70 and 71 shown in FIG. 14, the upper flap is the operating side and the lower flap is the driving side. In the case of manufacturing a corrugated cardboard sheet and the case of manufacturing a corrugated cardboard sheet in the opposite direction, different special ruled line rings having a mirror-symmetrical relationship with each other (that is, special ruled line rings 70 having the cross-sectional shape shown in FIG. 71 and a separate special ruled line ring having a cross-sectional shape that is mirror-symmetrical to the cross-sectional shape shown in FIG.

  However, since the number of ruled line rings that can be mounted on the corrugator ruled line forming device is limited, in addition to the normal ruled line ring that forms only the regular ruled line, separate special ruled line rings that are mirror-symmetrical to each other are formed. It is difficult to attach to the device.

  The problem to be solved by the present invention is that when both the regular ruled line and the reverse ruled line are formed on the corrugated cardboard sheet, the surface layer of the corrugated cardboard sheet is hardly deteriorated, and the corrugated cardboard sheet is oriented so that the upper flap faces the operating side. It is an object of the present invention to provide a method for producing a corrugated cardboard sheet that can use a common ruled line ring when it is manufactured and when a corrugated cardboard sheet is manufactured with the upper flap facing the drive side.

In order to solve the above problems, the present invention provides a method for producing a corrugated cardboard sheet having the following structure.
Specifically, a first corrugated cardboard sheet having a front liner, a back liner, and a center liner provided between the front liner and the back liner is sandwiched from the back liner side and the front liner side, respectively. Use the second ruled ring,
On the outer periphery of the first ruled ring, a convex portion that is continuous in the circumferential direction and a pair of concave portions that are located on both sides in the axial direction of the convex portion are provided, and the pair of concave portions are based on the convex portion. It has a symmetrical cross-sectional shape,
On the outer periphery of the second ruled ring, a pair of circumferentially extending groove portions arranged at intervals in the axial direction, a central mountain portion extending in the circumferential direction between the pair of groove portions, and the pair of groove portions A pair of groove shoulders located on the opposite side of the central mountain portion with respect to the central mountain portion, the pair of groove portions and the pair of groove shoulder portions are symmetric cross-section with respect to the central mountain portion The outer diameter of the central mountain portion is set larger than the outer diameter of the groove shoulder,
The first and second ruled rings have an axial direction between a relative position where the convex portion opposes one of the pair of groove portions and a relative position where the convex portion opposes the other groove portion. Relative movement is possible,
When the corrugated sheet is sandwiched between the convex portion and the groove portion, a regular ruled line having a recessed back liner is formed on the corrugated sheet, and at the same time, the corrugated sheet is sandwiched between the central mountain portion and the concave portion. A method for producing a corrugated cardboard sheet having a ruled line is formed on the corrugated sheet.

  In this way, when the corrugated sheet is sandwiched between the first and second crease rings, the convex part of the first crease line and the central mountain part of the second crease line are respectively the normal crease line and the reverse crease line of the cardboard sheet. Form. That is, since both the normal ruled line and the reverse ruled line can be formed only by sandwiching the corrugated cardboard sheet once, the surface layer deterioration of the corrugated cardboard sheet hardly occurs. In addition, the first and second ruled rings have an axis between a relative position where the convex portion faces one of the pair of groove portions and a relative position where the convex portion faces the other groove portion. Since the cardboard sheet is manufactured in such a direction that the upper flap is on the operating side and the cardboard sheet is manufactured in the direction in which the upper flap is on the driving side, the common ruled ring is used. Can be used.

This method for producing ruled line corrugated cardboard sheets can further include the following configuration.
The groove portion includes a cylindrical groove bottom surface, a slope on the central mountain portion side gradually increasing in diameter from the groove bottom surface toward the central mountain portion, and from the groove bottom surface to the opposite side of the central mountain portion. It has a slope on the groove shoulder side that gradually becomes a large diameter,
The slope on the central mountain side has a larger inclination angle than the slope on the groove shoulder side.

Moreover, in this invention, the thing of the following structures is provided as a ruled line ring set used for said corrugated cardboard sheet manufacturing method.
Specifically, the corrugated cardboard sheet having a front liner, a back liner, and a center shin provided between the front liner and the back liner is sandwiched from the front liner side and the back liner side. It consists of two ruled rings,
On the outer periphery of the first ruled ring, a convex portion that is continuous in the circumferential direction and a pair of concave portions that are located on both sides in the axial direction of the convex portion are provided, and the pair of concave portions are based on the convex portion. It has a symmetrical cross-sectional shape,
On the outer periphery of the second ruled ring, a pair of circumferentially extending groove portions arranged at intervals in the axial direction, a central mountain portion extending in the circumferential direction between the pair of groove portions, and the pair of groove portions A pair of groove shoulders located on the opposite side of the central mountain portion with respect to the central mountain portion, the pair of groove portions and the pair of groove shoulder portions are symmetric cross-section with respect to the central mountain portion The outer diameter of the central mountain portion is set larger than the outer diameter of the groove shoulder,
Providing a ruled ring set.

The ruled ring set can further have the following configuration.
The groove portion includes a cylindrical groove bottom surface, a slope on the central mountain portion side gradually increasing in diameter from the groove bottom surface toward the central mountain portion, and from the groove bottom surface to the opposite side of the central mountain portion. It has a slope on the groove shoulder side that gradually becomes a large diameter,
The slope on the central mountain side has a larger inclination angle than the slope on the groove shoulder side.

  According to the method for manufacturing a corrugated cardboard sheet according to the present invention, both the normal ruled line and the reverse ruled line can be formed only by sandwiching the corrugated cardboard sheet once. Moreover, it is possible to use a common ruled line ring when the cardboard sheet is manufactured with the upper flap facing the operating side and when the cardboard sheet is manufactured with the upper flap facing the driving side.

The figure which looked at the slitter scorer used for the corrugated cardboard sheet manufacturing method of the embodiment of this invention from the operation side The figure which shows the state which looked at the relative positional relationship of the axial direction of the 1st and 2nd ruled line ring shown in FIG. 1 from the upstream of the running direction of the cardboard sheet | seat. The relative positional relationship in the axial direction of the first and second ruled rings shown in FIG. 2 is moved from a relative position where the convex portion faces one of the pair of groove portions to a relative position which faces the other groove portion. Figure showing the state The figure which shows an example of the blank of the cardboard box which formed the normal ruled line and the reverse ruled line with the 1st and 2nd ruled line ring of the positional relationship shown in FIG. The figure which expands and shows a part of blank shown in FIG. Sectional view along line VI-VI in FIG. The figure which shows an example of the blank of the cardboard box which formed the normal ruled line and the reverse ruled line by the 1st and 2nd ruled line ring of the positional relationship shown in FIG. The perspective view which shows the cardboard box of the state before assembling the blank shown in FIG. 4 and folding an upper flap The perspective view which shows the state which folded the upper flap shown in FIG. 8 to the outer side of the surrounding wall, and inserted the goods in the cardboard box. The perspective view which shows the process of folding the upper flap shown in FIG. 9 inside a surrounding wall. The perspective view which shows the state which closed the upper end opening of the surrounding wall with the upper flap shown in FIG. 10, and sealed the cardboard box Sectional view along line XII-XII in FIG. Sectional view along line XIII-XIII in FIG. Sectional view showing the ruled line ring of the reference example Sectional drawing which shows the ruled line ring of the comparative example 2

  FIG. 1 shows a slitter scorer 1 used in a method for producing a ruled cardboard sheet according to an embodiment of the present invention. The slitter scorer 1 is disposed in the middle of a corrugator that manufactures a corrugated cardboard sheet 2, a slitter 3 that cuts the corrugated cardboard sheet 2 that is running on the corrugator along the running direction, and a running direction on the cardboard sheet 2 that is running on the corrugator And a scorer 4 (ruled line forming device) that forms a ruled line extending along the line.

  The scorer 4 includes rotating shafts 5 and 6 disposed above and below the corrugated cardboard sheet 2, a first ruled line 7 fixed to the upper rotating shaft 5, and a second shaft fixed to the lower rotating shaft 6. It has a ruled ring 8, and the corrugated cardboard sheet 2 is sandwiched between the first and second ruled rings 7, 8. A plurality of ruled ring sets 9 obtained by combining the first ruled ring 7 and the second ruled ring 8 are arranged at intervals in a direction orthogonal to the traveling direction of the cardboard sheet 2.

  As shown in FIG. 2, the corrugated cardboard sheet 2 includes a front liner 10, a back liner 11, and a center lining 12 provided between the front liner 10 and the back liner 11. In the corrugator, the corrugated cardboard sheet 2 travels in such a direction that the front liner 10 is on the lower side and the back liner 11 is on the upper side. On the outer periphery of the first ruled line ring 7, a convex portion 13 that is continuous in the circumferential direction over the entire circumference and a pair of concave portions 14 that are located on both sides in the axial direction of the convex portion 13 are provided. The pair of concave portions 14 has a symmetrical cross-sectional shape with respect to the convex portion 13.

  On the outer periphery of the second ruled ring 8, a pair of circumferentially extending groove portions 15 arranged at intervals in the axial direction, a central mountain portion 16 extending in the circumferential direction between the pair of groove portions 15, and a pair A pair of groove shoulders 17 located on the opposite side of the central mountain 16 from the groove 15 is provided. The pair of groove portions 15 and the pair of groove shoulder portions 17 have a symmetrical cross-sectional shape with respect to the central mountain portion 16. The outer diameter of the central mountain portion 16 is set larger than the outer diameter of the groove shoulder portion 17.

  The first and second ruled rings 7 and 8 have a relative position (see FIG. 2) in which the convex portion 13 faces one groove portion 15 of the pair of groove portions 15, and the convex portion 13 faces the other groove portion 15. The relative position (see FIG. 3) is relatively movable in the axial direction.

  As shown in FIG. 2, the first and second ruled line rings 7 and 8 sandwich the corrugated cardboard sheet 2 between the convex part 13 of the first ruled line ring 7 and the groove part 15 of the second ruled line ring 8. Then, the regular ruled line 20 having the concave side of the back liner 11 is formed on the corrugated cardboard sheet 2, and at the same time, the corrugated cardboard sheet 2 is placed between the central peak part 16 of the second ruled line ring 8 and the concave part 14 of the first ruled line ring 7. By sandwiching, a reverse ruled line 21 having a recessed side of the front liner 10 is formed on the cardboard sheet 2. Further, by inserting the corrugated cardboard sheet 2 between the groove shoulder 17 of the second ruled ring 8 and the concave part 14 of the first ruled ring 7, the weak reverse ruled line 22 in which the front liner 10 side is dented is also corrugated cardboard sheet 2. Formed. The weak reverse ruled line 22 is a weakly crushed line in which the front liner 10 side is recessed shallower than the reverse ruled line 21.

  The convex portion 13 of the first ruled line ring 7 is a maximum outer diameter portion formed at the axial center of the first ruled line ring 7. The concave portion 14 is a portion having an outer diameter smaller than the outer diameter of the convex portion 13. The concave portion 14 includes a cylindrical surface 23 having a constant outer diameter along the axial direction, and a slope 24 that gradually decreases in diameter from the convex portion 13 toward the cylindrical surface 23.

The groove portion 15 of the second ruled ring 8 includes a cylindrical groove bottom surface 25, a slope 26 on the side of the central mountain portion 16 that gradually increases in diameter from the groove bottom surface 25 toward the central mountain portion 16, and a groove bottom surface 25. And a slope 27 on the side of the groove shoulder 17 that gradually becomes larger in diameter toward the side opposite to the central mountain portion 16. The inclination angle θ ₁ of the slope 26 on the central mountain portion 16 side is larger than the inclination angle θ ₂ of the slope 27 on the groove shoulder portion 17 side.

The height h ₁ of the central mountain portion 16 with respect to the groove bottom surface 25 is set to be larger than the height h ₂ of the groove shoulder portion 17 with respect to the groove bottom surface 25. As a result, when the corrugated cardboard sheet 2 is sandwiched between the first and second ruled line rings 7, 8, the gap between one recess 14 of the first ruled line ring 7 and the central peak 16 of the second ruled line ring 8. Is smaller than the distance between the other recess 14 of the first ruled ring 7 and the groove shoulder 17 of the second ruled ring 8, and as a result, the one recess 14 and the central mountain portion 16 At the same time as the reverse ruled line 21 is formed, a weak reverse ruled line 22 is formed between the other recess 14 and the groove shoulder 17.

  As shown in FIG. 1, the slitter 3 is fixed to the rotary shafts 30 and 31 arranged above and below the corrugated cardboard sheet 2, the knife receiver 32 fixed to the upper rotary shaft 30, and the lower rotary shaft 31. And a slitter knife 33. On the outer periphery of the slitter knife 33, a continuous cutting edge is formed over the entire circumference in the circumferential direction. The slitter knife 33 is a rotary blade that cuts into the cardboard sheet 2 from the lower side (that is, the front liner 10 side) and cuts the cardboard sheet 2 along the traveling direction.

  The slitter scorer 1 includes a frame 34 that supports the upper rotary shafts 5, 30 and the lower rotary shafts 6, 31, a base member 35 fixed to the floor surface F, and between the frame 34 and the base member 35. And a linear guide 36 provided. The linear guide 36 supports the frame 34 so as to be movable in a horizontal direction perpendicular to the traveling direction of the cardboard sheet 2. Further, when the position of the cardboard sheet 2 passing through the slitter scorer 1 changes in a direction perpendicular to the running direction, a frame moving device 37 that moves the frame 34 following the change in the position of the cardboard sheet 2 is provided in the frame 34. Is attached.

  When the first ruled line 20 and the reverse ruled line 21 are formed on the cardboard sheet 2 using the first and second ruled rings 7 and 8, the cardboard sheet 2 is sandwiched once by the first and second ruled rings 7 and 8. Thus, both the normal ruled line 20 and the reverse ruled line 21 can be formed, so that the surface layer deterioration of the corrugated cardboard sheet 2 hardly occurs. That is, if a pair of ruled lines for forming the normal ruled lines 20 on the cardboard sheet 2 and a pair of ruled lines for forming the reverse ruled lines 21 on the cardboard sheet 2 are provided separately, the cardboard sheet 2 Since the same part of the cardboard is sandwiched twice by the ruled ring, the surface layer of the cardboard is deteriorated, the front liner 10 or the back liner 11 is peeled off, or the cardboard sheet 2 is folded to the back liner 11 side. There is a risk that the cardboard sheet 2 may be broken at both the regular ruled line 20 and the reverse ruled line 21 (two-stage folding). On the other hand, in the above-described embodiment, both the normal ruled line 20 and the reverse ruled line 21 are formed only by sandwiching the cardboard sheet 2 once by the first and second ruled line rings 7 and 8. Less likely to cause deterioration. Further, there is no possibility that an error occurs in the relative position between the regular ruled line 20 and the reverse ruled line 21, and the regular ruled line 20 and the reverse ruled line 21 can be formed with high dimensional accuracy.

  When the first ruled line 20 and the reverse ruled line 21 are formed on the corrugated cardboard sheet 2 by using the first and second ruled line rings 7 and 8, the first and second ruled line rings 7 and 8 Since the relative position of one of the pair of grooves 15 facing one of the grooves 15 and the relative position of the convex 13 facing the other groove 15 can be moved relative to each other in the axial direction, the upper flap ( When the cardboard sheet 2 is manufactured with the orientation toward the driving side (see FIG. 4) and when the cardboard sheet 2 is manufactured with the upper flap facing the operation side, the common ruled line rings 7 and 8 should be used. Is possible. That is, in general, in the corrugator that manufactures the corrugated cardboard sheet 2, as shown in FIG. 4, the corrugated cardboard sheet 2 is manufactured in such a direction that the upper flaps 48, 49, 50, 51 are on the driving side and the lower flap is on the operating side. As shown in FIG. 7, the cardboard sheet 2 may be manufactured in the opposite direction (that is, the direction in which the upper flaps 48, 49, 50, 51 are on the operation side and the lower flap is on the driving side). The operation side and drive side of the corrugator refer to one side and the other side in the horizontal direction orthogonal to the traveling direction of the cardboard sheet 2. Then, when the first ruled line 20 and the reverse ruled line 21 are formed on the cardboard sheet 2 using the first and second ruled line rings 7 and 8 of this embodiment, the first and second ruled line rings 7 and 8 are 2, the relative position where the convex portion 13 faces one of the pair of groove portions 15 and the relative position where the convex portion 13 faces the other groove portion 15 as shown in FIG. 3. The upper flaps 48, 49, 50, 51 are operated when the corrugated sheet 2 is manufactured in such a direction that the upper flaps 48, 49, 50, 51 are on the driving side. It is possible to use common ruled line rings 7 and 8 when manufacturing the corrugated cardboard sheet 2 in the direction of the side.

  In the above embodiment, the example in which the first ruled line ring 7 is arranged on the back liner 11 side and the second ruled line ring 8 is arranged on the front liner 10 side has been described. However, the first ruled line ring 7 is arranged on the front liner 10 side. It is also possible to arrange the second ruled ring 8 on the side of the liner 10 and on the back liner 11 side.

  Next, a corrugated cardboard box manufactured using the first and second ruled line rings 7 and 8 will be described.

  As shown in FIG. 4, the blank of the cardboard box is formed of corrugated cardboard having a front liner 10, a back liner 11, and a center lining 12 provided between the front liner 10 and the back liner 11. This blank has square side plates 41, 42, 43, 44 that are arranged in series via ruled lines 40. The ruled line 40 extends in a direction parallel to the corrugated cardboard. A seam 46 is connected to the side edge of the side plate 44 located at the end via a ruled line 45. The side plates 41, 42, 43, and 44 are parts that constitute the peripheral wall 47 (see FIG. 8) when the cardboard box is assembled.

  Upper flaps 48, 49, 50, 51 are connected to the upper edges of the side plates 41, 42, 43, 44, respectively. Between the side plates 41, 42, 43, 44 and the upper flaps 48, 49, 50, 51, the regular ruled line 20 and the reverse ruled line 21 are formed in parallel. The reverse ruled line 21 is formed at a position shifted to the upper flaps 48, 49, 50, 51 side with respect to the normal ruled line 20. The normal ruled line 20 and the reverse ruled line 21 extend in a direction perpendicular to the corrugated cardboard.

  Between the adjacent upper flaps 48, 49, 50, 51, a cut groove 52 parallel to the step is provided, and the upper flaps 48, 49, 50, 51 are separated from each other via the cut groove 52. It has become.

  Lower flaps 53, 54, 55, and 56 are connected to the lower edges of the side plates 41, 42, 43, and 44, respectively. Between the side plates 41, 42, 43, 44 and the lower flaps 53, 54, 55, 56, ruled lines 57 for folding the lower flaps 53, 54, 55, 56 inward (ruled lines in which the side of the back liner 11 is recessed) Is formed. The ruled line 57 extends in a direction perpendicular to the corrugated cardboard. Between the adjacent lower flaps 53, 54, 55, 56, a cut groove 58 parallel to the step is provided, and the lower flaps 53, 54, 55, 56 are separated from each other via the cut groove 58. It has become.

  As shown in FIGS. 5 and 6, the regular ruled line 20 is a groove-like ruled line that is recessed on the back liner 11 side, and the upper flaps 48, 49, 50, 51 are arranged on the back liner 11 side along the regular ruled line 20. (See FIG. 13). On the other hand, the reverse ruled line 21 is a groove-like ruled line in which the front liner 10 side is recessed, and the upper flaps 48, 49, 50, 51 can be folded to the front liner 10 side along the reverse ruled line 21. (See FIG. 12). A weak reverse ruled line 22 is formed on the opposite side of the normal ruled line 20 from the reverse ruled line 21 side.

  The blank shown in FIG. 4 can be assembled as follows, for example.

  As shown in FIG. 8, the side plates 41, 42, 43, 44 are bent into a cylindrical shape along the ruled line 40 so that the back liner 11 is on the inside, and the seam 46 connected to the one side plate 44 is connected to the other end. These side plates 41, 42, 43 and 44 form a peripheral wall 47. Next, the lower flaps 53 and 55 connected to the lower ends of the side plates 41 and 43 corresponding to the width surface of the cardboard box are bent inside the peripheral wall 47 along the ruled line 57, and then correspond to the length surface of the cardboard box. The bottom flaps 54, 56 connected to the lower ends of the side plates 42, 44 are bent along the ruled line 57 to the inside of the peripheral wall 47, and the bottom flaps 53, 54, 55, 56 close the lower end opening of the peripheral wall 47. 59 is formed.

  Next, the product is boxed. At this time, as shown in FIG. 8, the product 60 (see FIG. 9) can be inserted into the cardboard box with the upper flaps 48, 49, 50, 51 extending straight above the peripheral wall 47. However, in particular, when the product 60 is manually inserted, in the state shown in FIG. 8, the upper flaps 48, 49, 50, 51 are difficult to insert the product 60.

  Therefore, in order to facilitate insertion of the product 60 into the cardboard box, the upper flaps 48, 49, 50, 51 are folded outside the peripheral wall 47 (so-called reverse folding) as shown in FIG. Here, since the regular ruled line 20 has a groove shape in which the back liner 11 side is recessed, when the upper flaps 48, 49, 50, 51 are folded to the back liner 11 side, the upper flaps 48, 49, 50. , 51 can be smoothly folded along the regular ruled line 20, but a relatively large force is required to fold the upper flaps 48, 49, 50, 51 along the regular ruled line 20 toward the front liner 10. . On the other hand, since the reverse ruled line 21 has a groove shape with the front liner 10 side recessed, when the upper flaps 48, 49, 50, 51 are folded to the front liner 10 side, the upper flaps 48, 49, 50, 51 is smoothly folded along the reverse ruled line 21, but has a characteristic that a relatively large force is required to fold the upper flaps 48, 49, 50, 51 along the reverse ruled line 21 toward the back liner 11. Therefore, when the upper flaps 48, 49, 50, 51 are folded outside the peripheral wall 47, the upper flaps 48, 49, 50, 51 are not folded at the regular ruled line 20 but are folded along the reverse ruled line 21 ( (See FIG. 12).

  Although FIG. 9 shows an example in which the upper flaps 48, 49, 50, 51 are all folded, only one of the upper flaps 48, 49, 50, 51 (for example, as viewed from a boxing operator). You may make it fold the thing on the near side.

  After that, as shown in FIGS. 10 and 11, the upper flaps 48 and 50 are bent inside the peripheral wall 47 along the regular ruled line 20, and then the upper flaps 49 and 51 are inside the peripheral wall 47 along the regular ruled line 20. Bend it. Here, when the upper flaps 48, 49, 50, 51 are folded inside the peripheral wall 47 (forward fold), the upper flaps 48, 49, 50, 51 depend on the characteristics of the regular ruled line 20 and the reverse ruled line 21 described above. Instead of folding along the reverse ruled line 21, it will be folded along the regular ruled line 20 (see FIG. 13). Further, as shown in FIG. 6, since the weak reverse ruled line 22 is formed on the opposite side of the reverse ruled line 21 with respect to the regular ruled line 20, as shown in FIG. When folding the flaps 48, 49, 50, 51 to the back liner 11 side (that is, the inside of the box), the upper flaps 48, 49, 50, 51 can be folded with high accuracy along the regular ruled line 20. Yes. Thereafter, the upper flaps 48, 49, 50, 51 shown in FIG. 11 are fixed by a fixing means (not shown) such as an adhesive tape, a stapler, or a hot melt, thereby completing the sealing of the box.

  Since this corrugated cardboard box is manufactured by forming both the normal ruled line 20 and the reverse ruled line 21 by sandwiching the corrugated cardboard sheet 1 once, the corrugated cardboard sheet 2 is formed at the base of the upper flaps 48, 49, 50, 51. Such problems as surface layer deterioration, peeling of the front liner 10 or the back liner 11 from the shin 12 and two-stage folding are unlikely to occur. When the cardboard sheet 2 is manufactured with the upper flaps 48, 49, 50, 51 facing the operating side, and when the cardboard sheet 2 is manufactured with the top flaps 48, 49, 50, 51 facing the drive side Since the common ruled ring 7 and 8 are used, the manufacturing cost can be kept low.

  As described above, the cardboard box is formed with the groove-like reverse ruled line 21 in which the front liner 10 side is recessed so that the upper flaps 48, 49, 50, 51 are folded outside the peripheral wall 47. Easy to box. Further, when the upper flaps 48, 49, 50, 51 are folded toward the back liner 11, the upper flaps 48, 49, 50, 51 can be accurately folded along the regular ruled line 20, so that the upper flaps 48, When the boxes 49, 50, 51 are folded inside the box and the box is sealed, it is possible to prevent a gap from being generated between the tips of the upper flaps 49, 51, and the butt accuracy of the upper flaps 49, 51 is improved. Excellent.

  The corrugated sheet 2 of Example 1 in which the first and second ruled rings 7 and 8 having the cross-sectional shape shown in FIG. A test was carried out to confirm that when the cardboard sheet 2 was folded along the ruled line 20 to the side of the back liner 11, the corrugated cardboard sheet 2 was less likely to be broken at both the regular ruled line 20 and the reverse ruled line 21).

  In Comparative Example 1 of this test, the pair of ruled lines for forming the normal ruled line 20 on the cardboard sheet 2 and the pair of ruled rings for forming the reverse ruled line 21 on the cardboard sheet 2 are run on the cardboard sheet 2. By providing the cardboard sheet 2 in order with the ruled ring, the normal ruled line 20 and the reverse ruled line 21 at the base of the upper flaps 48, 49, 50, 51 are sequentially arranged. Formed.

  The corrugated cardboard sheet 2 used in Example 1 and Comparative Example 1 was of a B flute in which the material of the front liner 10, the center lining 12, and the back liner 11 were C160, S120, and C160, respectively.

  In Example 1 and Comparative Example 1, after forming a regular ruled line 20 and a reverse ruled line 21 on each of a plurality of cardboard sheets 2, each cardboard sheet 2 was cut into a 250 mm × 300 mm square, and the standard state (temperature 23 ° C., The humidity is adjusted for 24 hours at a humidity of 50% RH, and then the cardboard sheet 2 is folded (reversely folded) along the reverse ruled line 21 toward the front liner 10, and then the cardboard sheet 2 along the regular ruled line 20. Was folded to the side of the liner 11 (forward fold). When this normal folding was performed, it was investigated whether the corrugated cardboard sheet 2 could be folded along only the regular ruled line 20 without being folded at the reverse ruled line 21.

The results of this test are shown in the following table.

In the above table, the ruled line gap is the distance of the part forming the regular ruled line between the pair of ruled rings (in Example 1, the tip surface of the convex portion 13 of the first ruled ring 7 and the groove of the second ruled ring 8). 15 distances from the groove bottom surface 25).
Further, in the above table, “◯” indicates that the corrugated sheet 2 of all samples was not folded at the reverse ruled line 21 but was folded along only the regular ruled line 20 when “normal” was performed, and “△” Among all the samples, some of the samples were folded along only the regular ruled line 20, but the remaining samples indicate that a two-stage folding failure occurred, and “×” indicates 2 in the corrugated cardboard sheet 2 of all the samples. This indicates that a problem with step folding has occurred.

  From this test result, it can be confirmed that when the ruled-line corrugated cardboard sheet 2 is manufactured by the ruled-line corrugated cardboard sheet manufacturing method of the above-described embodiment, it is difficult to cause a problem of two-stage folding.

  Further, Example 2 in which the normal ruled line 20 and the reverse ruled line 21 are formed by the first and second ruled line rings 7 and 8 (see FIG. 2) of the above embodiment, and a pair of upper and lower ruled line rings 80 and 81 shown in FIG. In Comparative Example 2 in which the regular ruled line 20 and the reverse ruled line 21 are formed in the above, the bending strength when the cardboard sheet 2 is folded to the side of the back liner 11 along the regular ruled line 20 (forward fold), and the corrugated sheet 2 are reversed ruled lines. A test was performed to measure the bending strength when folded to the side of the front liner 10 along line 21 (reverse folding). In the comparative example 2 in which the normal ruled line 20 and the reverse ruled line 21 are formed by the pair of upper and lower ruled line rings 80 and 81 shown in FIG. 15, the weak reverse ruled line 22 shown in FIG. 2 is not formed.

  The corrugated cardboard sheet 2 used in Example 2 and Comparative Example 2 was of a B flute in which the material of the front liner 10, the center lining 12, and the back liner 11 were C160, S120, and C160, respectively.

  In Example 2 and Comparative Example 2, after forming a regular ruled line 20 and a reverse ruled line 21 on each of a plurality of corrugated cardboard sheets 2, each corrugated cardboard sheet 2 was cut into a 100 mm × 150 mm square, and the standard state (temperature 23 ° C., The humidity is adjusted for 24 hours at a humidity of 50% RH), and the folding strength when folding the cardboard sheet 2 toward the back liner 11 along the regular ruled line 20 (folding strength at the time of regular folding) and along the reverse ruled line 21. Then, the bending strength (folding strength at the time of reverse folding) when the corrugated cardboard sheet 2 was folded to the front liner 10 side was measured.

（単位：Ｎ） The results of this test are shown in the following table.

(Unit: N)

  As a result of this test, when the normal ruled line 20 and the reverse ruled line 21 are formed by the first and second ruled line rings 7 and 8 (see FIG. 2) of the above embodiment, the bending strength at the time of reverse folding is as shown in FIG. This is almost the same as the case where the regular ruled line 20 and the reverse ruled line 21 are formed by the pair of ruled line rings 80 and 81, but the case where the regular ruled line 20 and the reverse ruled line 21 are formed by the pair of upper and lower ruled line rings 80 and 81 shown in FIG. It can be seen that the bending strength at the time of forward folding can be reduced (that is, the upper flaps 48, 49, 50, 51 shown in FIG. 8 are easily folded inside the peripheral wall 47).

2 Corrugated sheet 7 First crease ring 8 Second crease ring 10 Front liner 11 Back liner 12 Middle ridge 13 Convex part 14 Concave part 15 Groove part 16 Central mountain part 17 Groove shoulder part 20 Regular crease line 21 Reverse crease line 25 Groove bottom face 26, 27 slope

Claims (4)

A traveling corrugated cardboard sheet (2) having a front liner (10), a back liner (11), and a center shin (12) provided between the front liner (10) and the back liner (11). Using the first and second ruled rings (7, 8) sandwiched from the back liner (11) side and the front liner (10) side,
On the outer periphery of the first ruled ring (7), a convex portion (13) continuous in the circumferential direction and a pair of concave portions (14) located on both sides in the axial direction of the convex portion (13) are provided. The pair of concave portions (14) have a symmetrical cross-sectional shape with respect to the convex portion (13),
On the outer periphery of the second ruled line ring (8), a pair of grooves (15) extending in the circumferential direction and spaced apart in the axial direction, and extending between the pair of grooves (15) in the circumferential direction. A central mountain portion (16) and a pair of groove shoulder portions (17) positioned on the opposite side of the central mountain portion (16) with respect to the pair of groove portions (15) are provided. The groove portion (15) and the pair of groove shoulder portions (17) have a symmetrical cross-sectional shape with respect to the central mountain portion (16), and the outer diameter of the central mountain portion (16) is the groove shoulder. Set larger than the outer diameter of the portion (17),
The first and second ruled rings (7, 8) include a relative position where the convex portion (13) faces one groove portion (15) of the pair of groove portions (15), and the convex portion (13 ) Can be relatively moved in the axial direction between the relative position facing the other groove (15),
At the same time as forming a regular ruled line (20) in which the back liner (11) side is recessed by sandwiching the cardboard sheet (2) between the convex part (13) and the groove part (15) on the cardboard sheet (2), A ruled line that forms a reverse ruled line (21) in which the front liner (10) side is recessed by sandwiching the cardboard sheet (2) between the central mountain part (16) and the recessed part (14) in the cardboard sheet (2). Corrugated cardboard sheet manufacturing method. The groove portion (15) includes a cylindrical groove bottom surface (25), and a slope (26 on the side of the central mountain portion (16) that gradually increases in diameter from the groove bottom surface (25) toward the central mountain portion (16). ) And a slope (27) on the groove shoulder (17) side that gradually increases in diameter from the groove bottom surface (25) toward the side opposite to the central mountain portion (16),
The ruled-line corrugated cardboard sheet manufacturing method according to claim 1, wherein the slope (26) on the central mountain portion (16) side has a larger inclination angle than the slope (27) on the groove shoulder portion (17) side. A traveling corrugated cardboard sheet (2) having a front liner (10), a back liner (11), and a center shin (12) provided between the front liner (10) and the back liner (11). The first and second ruled ring (7, 8) sandwiched from the front liner (10) side and the back liner (11) side,
On the outer periphery of the first ruled ring (7), a convex portion (13) continuous in the circumferential direction and a pair of concave portions (14) located on both sides in the axial direction of the convex portion (13) are provided. The pair of concave portions (14) have a symmetrical cross-sectional shape with respect to the convex portion (13),
On the outer periphery of the second ruled line ring (8), a pair of grooves (15) extending in the circumferential direction and spaced apart in the axial direction, and extending between the pair of grooves (15) in the circumferential direction. A central mountain portion (16) and a pair of groove shoulder portions (17) positioned on the opposite side of the central mountain portion (16) with respect to the pair of groove portions (15) are provided. The groove portion (15) and the pair of groove shoulder portions (17) have a symmetrical cross-sectional shape with respect to the central mountain portion (16), and the outer diameter of the central mountain portion (16) is the groove shoulder. Set to be larger than the outer diameter of the portion (17),
Ruled line ring set. The groove portion (15) includes a cylindrical groove bottom surface (25), and a slope (26 on the side of the central mountain portion (16) that gradually increases in diameter from the groove bottom surface (25) toward the central mountain portion (16). ) And a slope (27) on the groove shoulder (17) side that gradually increases in diameter from the groove bottom surface (25) toward the side opposite to the central mountain portion (16),
The ruled ring set according to claim 3, wherein the inclined surface (26) on the central mountain portion (16) side has a larger inclination angle than the inclined surface (27) on the groove shoulder portion (17) side.

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