GB2283765A

GB2283765A - Single facer in corrugator

Info

Publication number: GB2283765A
Application number: GB9422145A
Authority: GB
Inventors: Eiichi Isowa
Original assignee: Isowa KK
Current assignee: Isowa KK
Priority date: 1993-11-05
Filing date: 1994-11-01
Publication date: 1995-05-17
Also published as: JPH07125114A; ITMI942247A1; IT1276055B1; ITMI942247A0; GB9422145D0; DE4439403A1

Description

SINGLE FACER IN CORRUGATOR

BACKGROUND OF THE INVENTION

Field of the Invention

2283765 This invention relates to an apparatus for forming a single-faced corrugated board sheet consisting of a corrugating medium and a liner which are pasted together.

Description of the Related Art

In an apparatus for forming a single-faced corrugated board sheet (socalled single facer), an upper fluted roll and a lower fluted roll each having wavy flutes formed on the circumference are rotatably supported between frames in a vertical relationship in such a way that they may engage with each other by their flutes, and a press roll is designed to be brought into press contact with the lower fluted roll via a corrugating medium and a liner which are the webs of the single-faced corrugated board sheet. Namely, the corrugating medium, which is fed between the upper fluted roll and the lower fluted roll, is allowed to have a predetermined corrugation (flutes) when it passes between these rolls. A starchy glue is applied to the crests of corrugation thus formed by a gluing roll provided in a gluing mechanism. meanwhile, the liner being fed from the side opposite to the corrugating medium via the press roll is pressed against the glued crests of the corrugating medium between the press roll and the lower fluted roll to be pasted together and form a single-faced corrugated board sheet.

The press roll employed in the conventional single facer is of a largediameter metallic roll which is normally urged toward the lower fluted roll so as to apply a predetermined nip pressure to the corrugating medium and liner passing 2 - between these rolls. Since flutes consisting of continuous alternative repetition of crests and troughs are formed at a predetermined pitch on the circumference of the lower fluted roll, the rotation center of the lower fluted roll and that of the press roll shift slightly as the point of press contact therebetween shifts from the trough to the crest or vice versa. Thus, as the result that the rotation centers of these rolls make cyclic reciprocating motions to be closer to or farther from each other as they rotate, great vibration and big noise are generated during formation of the single-faced corrugated board, causing the working environment in the plant to be worsened considerably. Besides, since both the press roll and the lower fluted roll are made of rigid metallic materials, an impact is periodically applied to the press roll (so-called the hammer phenomenon) every time the crests of the lower fluted roll are abutted against the press roll. Accordingly, linear press marks corresponding to the pitch of the crests of the lower fluted roll are formed horizontally on the surface of the liner in the thus formed single- faced corrugated board sheet, disadvantageously.

In the single facer where a press roll and a lower fluted roll are employed as described above, these two rolls are brought into linear contact with each other via the corrugating medium and liner, so that the corrugating medium and the liner are nipped therebetween merely over a very narrow zone. Accordingly, if the speed of forming a single-faced corrugated board is set at a high level to shorten the time that the corrugating medium and liner pass between these two rolls, it is liable that the corrugating medium fails to be securely pasted with the liner. Thus, high-speed running of the single facer has been difficult. In addition, due to the same reason, pasting of a thick corrugating medium with a thick liner cannot successfully be achieved, disadvantageously.

A countermeasure for the problems described above is proposed, in which a corrugating medium and a liner are pasted together using an endless belt in place of the press roll. In such type of single facer, a pair of rolls over which the endless belt is extended are rotatably disposed adjacent to the lower fluted roll, and the liner is designed to be brought into press contact with the crests of the corrugating medium between the endless belt extended over these rolls and the lower fluted roll. Namely, the use of the endless belt can prevent generation of noise and also formation of press marks. Further, since the zone where the corrugating medium and the liner are nipped can be secured over a wide area, high speed operation of forming single-faced corrugated board sheets can be realized.

In the single facer employing such endless belt, the tension of the endless belt is adapted to be varied by changing the distance between the pair of rolls over which the endless belt is extended so as to achieve adjustment of the nip pressure to be applied to the corrugating medium and liner. Therefore, there is pointed out a problem that it is difficult to make delicate adjustment of the nip pressure by changing the tension, and the adjustment operation becomes extremely intricate. Besides, it can also be pointed out that the structure of the single facer itself becomes complicated, because a mechanism for moving and adjusting the rolls must be disposed, leading to enlargement of the single facer and cost elevation. Incidentally, a drive means for running the endless belt in synchronization with the speed of the corrugating medium and liner is also required, which also contributes to the cost elevation.

This invention has been proposed in view of the disadvantages inherent in the prior art single facers and in order to overcome them in a successful manner, and is directed to provide an inexpensive single facer having a simple structure, which can minimize vibration or noise during the operation and also can cope with high-speed formation of single-faced corrugated boards.

SUMMARY OF THE INVENTION

In order to solve the problems described above and to attain the intended objects suitably, this invention provides a single facer provided with an upper fluted roll having wavy flutes formed on the circumference, a lower fluted roll having wavy flutes formed on the circumference which engage with those of the upper fluted roll and form a predetermined corrugation on a corrugating medium to be passed between the upper fluted roll and the lower fluted roll and a gluing mechanism for gluing the crests of the thus corrugated corrugating medium, in which a liner is pasted onto the glued crests of the corrugating medium so as to form a single-faced corrugated board; the single facer comprising a fixed supporting member disposed adjacent to and to oppose to the lower fluted roll via a route of feeding the liner; a sleeve-like endless belt wound around the supporting member to be able to rotate freely therearound; and a pressing member disposed to oppose, via the endless belt wound around the supporting member, to the lower fluted roll to be parallel therewith; the pressing member being able to be moved, while maintaining the horizontal posture, closer to the lower fluted roll under urging by a predetermined urging means; wherein the pressing member is moved closer to the lower fluted roll under the action of the urging means to bring that portion of the endless belt opposing to the pressing member closer to the lower fluted roll, so that the liner may be brought into press contact by the endless belt with - 5 the glued crests of the corrugating medium fed along the circumference of the lower fluted roll.

BRIEF DESCRIPTION OF THE DRAWINGS

The features of this invention that are believed to be novel are set forth with particularity in the appended claims. The invention, together with the objects and advantages thereof, may best be understood by reference to the following description of the preferred embodiments taken in conjunction with the accompanying drawings in which:

Fig. 1 shows, in partial cross section, a side view of the major section of a single facer according to a preferred embodiment of the invention; Fig. 2 shows, in partial cross section, a front view of the major section of the single facer according to the preferred embodiment of the invention; Fig. 3 shows schematically a partially cutaway perspective view of a supporting roll according to the preferred embodiment of the invention; Fig. 4 shows schematically, in partial cross section, a constitution of the single facer according to the preferred embodiment of the invention; Fig. 5 shows, in vertical cross-section, a variation of the arrangement of the endless belt with respect to the supporting roll according to the preferred embodiment of the invention; Fig. 6 shows an explanatory view of the major section of a variation of the means for urging a pressing member according to the preferred embodiment of the invention; and Fig. 7 shows schematically a front view of the single facer employing a variation of the means for retaining the corrugating medium in the lower fluted roll according to the preferred embodiment of the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Next, the single facer of the invention will now be described by way of a preferred embodiment referring to the attached drawings. It should be noted here that the distinction between the upper fluted roll and the lower fluted roll is not made based on the spatial relationship but made relative to the endless belt and that such fluted roll as is brought into press contact with the endless belt via the liner and corrugating medium is appreciated to be "the lower fluted roll". Namely, in the embodiments described herein, while the upper fluted roll, the lower fluted roll and the endless belt are arranged downward in this order, it is of course possible to apply this invention to a system where the endless belt, the lower fluted roll and the upper fluted roll are arranged downward in this order.

Fig. 1 shows, in partial cross section, a side view of the major section of the single facer according to a preferred embodiment of the invention, and Fig. 4 shows schematically the constitution of the single facer according to the preferred embodiment of the invention. A pair of fixed frames (not shown) are disposed on the floor of a plant to be spaced from each other orthogonal to the direction of feeding a corrugating medium 10, and an upper fluted roll 12 having wavy flutes formed on the circumference and a lower fluted roll 14 also having wavy flutes formed on the circumference are rotatably supported therebetween. The rotation center of the upper fluted roll 12 locates diagonally above that of the lower fluted roll 14, and the respective rolls are designed to be engaged with each other by their flutes via the corrugating medium 10. A gluing mechanism 20 consisting of a gluing roll 16 and a doctor roll 18 is disposed immediately below the upper fluted roll 12 and diagonally below the lower fluted roll 18. The corrugating medium 10 is fed from a web feeding source (not shown) assumed to locate on the left side of Fig. 4 through a guide roll 22 to the engagement zone defined between the upper fluted roll 12 and the lower fluted roll 14, and thus a predetermined corrugation can be formed on the corrugating medium 10 by passing through this zone. The thus corrugated corrugating medium 10 is glued at the crests of corrugation by the gluing mechanism 20 and then diverted upward along the circumference of the lower fluted roll 14.

Incidentally, the lower fluted roll 14 has a plurality of circumferential grooves 14a (see Fig. 1) formed on the circumference thereof, and a suction means 24 is disposed on one side of the lower fluted roll 14 opposite to the position where the corrugating medium 10 is allowed to pass. The suction means 24 is actuated to generate a negative pressure in the circumferential grooves 14a of the lower fluted roll 14, and thus the corrugating medium 10 having a predetermined corrugation is adapted to be fed stably as sucked onto the circumference of the lower fluted roll 14.

As shown in Fig. 1, a pair of brackets 26 stand, as spaced from each other in the axial direction of the lower fluted roll 14, from the floor of a plant, and a supporting roll 28 having a predetermined diameter is supported between these brackets 26 to be parallel with the lower fluted roll 14. The circumference of the supporting roll 28 locates 8 - close to the lower fluted roll 14 with a predetermined clearance. Further, an endless belt 30 having a sleevelike form and also having an inner diameter slightly greater than the outer diameter of the roll 28 is wound slidably around the supporting roll 28. The width of the endless belt 30 is designed to be greater than those of the corrugating medium 10 and of liner 32, so that the corrugating medium 10 fed along the circumference of the lower fluted roll 14 and the liner 32 to be pasted therewith may be nipped over the full width thereof between the endless belt 30 and the lower fluted roll 14 by moving the endless belt 30 toward the lower fluted roll 14 by a pressing member 34 (to be described later). Incidentally, a seamless resin belt can suitably be used as the endless belt 30.

An elongated groove 28a is formed on the supporting roll 28 to be parallel with the lower fluted roll 14 at the position opposing via the endless belt 30 to the rotation center of the lower fluted roll 14, and a pressing member 34 is fitted in the elongated groove 28a to be slidable in the radial direction of the supporting roll 28. A pressure space 36 is defined between the bottom of the pressing member 34 and the bottom of the elongated groove 28a, and the space 36 communicates to a supply pipe 38 led out of an air supply source (not shown) and arranged through the supporting roll 28. Namely, by feeding a compressed air to the pressure space 36 through the supply pipe 38, the pressing member 34 can be moved radially outward, while maintaining the horizontal posture, along the elongated groove 28a under the action of the compressed air, and the outer surface of the pressing member 34 projects above the circumference of the supporting roll 28. Thus, as shown in Fig. 2, that portion of the endless belt 30 wound around the supporting roll 28 which opposes to the pressing member 34 can be brought closer to the lower fluted roll 14. As shown in Figs. 1 and 3, the pressing member 34 is designed to be longer than the width of the endless belt 30, so that a uniform nip pressure may be applied over the entire width of the corrugating medium 10 and the liner 32 when the endless belt 30 is moved closer to the lower fluted roll 14 by the pressing member 34. Incidentally, a sealing member is interposed between the outer surface of the pressing member 34 and the inner surface of the elongated groove 28a, so that the compressed air in the pressure space 36 may not escape therefrom.

The outer surface of the pressing member 34 is arcuated after the circumference of the lower fluted roll 14, so that the corrugating medium 10 and the liner 32 may be nipped between the pressing member 34 and the lower fluted roll 14 over a predetermined length. Thus, if the speed of forming a single-faced corrugated board is set at a high level, the corrugating medium 10 is adapted to be securely pasted with the liner 32. Incidentally, since the endless belt 30 is allowed to slide along the circumference of the supporting roll 28 as the liner 32 runs when the belt 30 is pressed against the liner 32 by the pressing member 34, it is recommended to supply a lubricant between the endless belt 30 and the supporting roll 28 so as to minimize the frictional resistance therebetween. Otherwise, the inner surface of the endless belt 30 and the circumference of the supporting roll 28 may be coated with a material having a very low frictional resistance etc. It should be noted, however, that the endless belt 30 is designed to be moved as abutted against the liner 32 following the running thereof, so that the outer surface of the endless belt 30 to be abutted against the liner 32 is desirably made of or treated with a material which does not cause slipping with the liner 32.

It is also recommended to form regulating members on the circumference of the supporting roll 28 so as to regulate the axial shifting of the endless belt 30 or to form a groove which is substantially as wide as the endless belt 30 on the circumference of the supporting roll 28 so as to allow the endless belt 30 to slide in this groove. Further, a hot steam may be circulated through the inner space of the supporting roll 28 and warm the bonding areas of the corrugating medium 10 with the liner 32 via the endless belt 30 so as to accelerate bonding therebetween.

Next, the operation of the single facer according to the above embodiment will be described. When the single facer according to this invention is to be operated, a compressed air is supplied to the pressure space 36 through the supply pipe 38. Thus, the pressing member 34 is moved radially outward along the elongated groove 28a, and the endless belt 30 wound around the supporting roll 28 is pushed closer to the lower fluted roll 14. Accordingly, as shown in Fig. 2, the liner 32 is pressed via the endless belt 30 against the corrugating medium 10 fed along the circumference of the lower fluted roll 14. The endless belt 30 pressed against the liner 32 slides along the circumference of the supporting roll 28 as the liner 32 and the corrugating medium 10 run. Namely, the corrugating medium 10 and the liner 32 are nipped over a predetermined length between the lower fluted roll and that portion of the endless belt 30 opposing to the pressing member 34 to achieve secured bonding therebetween at the glued portions. Incidentally, the nip pressure to be applied to the corrugating medium 10 and the liner 32 can easily be secured with high accuracy by adjusting the amount of the compressed air to be fed to the pressure space 36.

As described above, since the corrugating medium 10 is brought into press contact with the liner 32 with the aid of the endless belt 30 wound around the supporting roll 28, 11 - not only the vibration and noises which are liable to be generated during the formation of a single-faced corrugated board but also the press marks to be formed on the liner of the single-faced corrugated board can greatly be minimized. Further, since the endless belt 30 is designed to slide as the liner 32 runs, no positive means for driving the endless belt 30 is necessary, and thus the mechanism can be simplified. Further, the adjustment of the nip pressure can be achieved by allowing a part of the endless belt to approach the lower fluted roll 14, so that no means for shifting and adjusting the heavy supporting roll 28 is necessary, leading to simplification of the structure and cost reduction. In addition, while the endless belt wears away with time, the belt 30 is inexpensive, and thus the running cost can be held low. Moreover, since the supporting roll 28 is -ixed, the supply pipe 38 for feeding a compressed air, the means for feeding a lubricant (not shown) and the means for supplying a hot steam (not shown) can easily be arranged.

Fig. 5 shows a variation of the arrangement of the endless belt 30 with respect to the supporting roll 28, in which discs 42 are fitted rotatably on the small-diameter shaft portions 28b formed at each end portion of the supporting roll 28 via bearings 40, respectively. The diameter of each disc 42 is designed to be greater than that of the supporting roll 28, and the endless belt 30 extended between these discs 42 to be fixed on the circumferences thereof is designed to extend outer than the supporting roll 28. In this variation, when the endless belt 30 is pressed against the liner 32 with the aid of the pressing member 34, the endless belt 30 and the discs 42 rotate relative to the supporting roll 28 as the liner 32 runs.

Fig. 6 shows a variation of the means for moving the pressing member 34, in which a pantographic lifter 44 is - 12 disposed in the elongated groove 28a of the supporting roll 28, and the pressing member 34 is designed to be reciprocated in the radial direction of the supporting roll 28 along the elongated groove 28a by positively or negatively operating the lifter 44 by a cylinder 46. The use of such lifter 44 enables shifting of the pressing member 34 closer to or farther from the lower fluted roll 14, while maintaining the horizontal posture.

While a suction system was described as the technique of retaining the corrugating medium 10 on the lower fluted roll 14 in the embodiment shown in Fig. 4, a pressing method (overpressure method), for example, as shown in Fig. 7 can also be employed. Namely, a pressure chamber 48, in which the gluing mechanism 20 is housed, is disposed immediately below the upper fluted roll 12 and diagonally below the lower fluted roll 14, and the pressure chamber 48 is let open toward the upper fluted roll 12 and the lower fluted roll 14, with the opening edges being brought closer to the upper fluted roll 12 and the supporting roll 28. Further, a compressed air is supplied from a source (not shown) to the pressure chamber 48 to provide therein a pressure slightly higher than the atmospheric pressure. In this case, the outer surface of the lower fluted roll 14 facing the pressure chamber 48 is assuming the atmospheric pressure by virtue of the circumferential grooves 14a defined at predetermined intervals in the axial direction. Accordingly, the corrugating medium 10 corrugated by passing between the upper fluted roll 12 and the lower fluted roll 14 can be fed stably as pressed against the roll surface due to the difference between the pressure in the pressure chamber 48 and that on the circumference of the lower fluted roll 14.

In the embodiment shown in Figs. 1 to 4, as the means for reducing resistance between the supporting roll 28 and the endless belt 30 which slides as the liner 32 runs, there may be employed, for example, a method in which the frictional resistance between the roll 28 and the endless belt 30 is designed to be reduced with the aid of the air blown through a plurality of air bleed holes formed to open to the circumference of the supporting roll 28. Further, it is also possible to provide a plurality of bearings on the circumference of the supporting roll 28.

It should be apparent to those skilled in the art that the present invention may be embodied in many other specific forms without departing from the spirit or scope of the invention. Therefore, the present example and embodiment are to be considered as illustrative and not restrictive and the invention is not to be limited to the details given herein, but may be modified within the scope of the appended claims.

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Claims

What is Claimed is:

1. A single facer provided with an upper fluted roll (12) having wavy flutes formed on the circumference, a lower fluted roll (14) having wavy flutes formed on the circumference which engage with those of said upper fluted roll (12) and form a predetermined corrugation on a corrugating medium (10) to be passed between said upper fluted roll (12) and said lower fluted roll (14) and a gluing mechanism (20) for gluing the crests of the thus corrugated corrugating medium (10), in which a liner (32) is pasted onto the glued crests of said corrugating medium (10) so as to form a single-faced corrugated board; said single facer comprising: a fixed supporting member (28) disposed adjacent to and to oppose to said lower fluted roll (14) via a route of feeding said liner (32); a sleeve- like endless belt (30) wound around said supporting member (28) to be able to rotate freely therearound; and a pressing member (34) disposed to oppose, via said endless belt (30) wound around said supporting member (28), to said lower fluted roll (14) to be parallel therewith; said pressing member (34) being able to be moved, while maintaining the horizontal posture, closer to said lower fluted roll (14) under urging by a predetermined urging means; wherein said pressing member (34) is moved closer to said lower fluted roll (14) under the action of said urging means to bring that portion of said endless belt (30) opposing to said pressing member (34) closer to said lower fluted roll (14), so that said liner (32) may be brought into press contact by said endless belt (30) with the glued crests of said corrugating medium (10) fed along the circumference of said lower fluted roll (14).

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2. The single facer according to Claim 1, wherein a pair of discs (42) each having a diameter greater than that of said supporting member (28) are rotatably disposed thereon at the positions spaced with a predetermined distance along the width of said supporting member (28), and an endless belt (30) is extended between said discs (42) to be fixed on the circumferences thereof.

3. A single facer substantially as hereinbefore described with reference to the accompanying drawings.