GB2287483A

GB2287483A - A single-facer with secondary pressing contact

Info

Publication number: GB2287483A
Application number: GB9504680A
Authority: GB
Inventors: Eiichi Isowa; Toshihiko Yasui
Original assignee: Isowa KK
Current assignee: Isowa KK
Priority date: 1994-03-15
Filing date: 1995-03-08
Publication date: 1995-09-20
Anticipated expiration: 2015-03-08
Also published as: JPH07251469A; GB9504680D0; DE19509182A1; GB2287483B

Description

SINGLE FACER IN CORRUGATOR

BACKGROUND OF THE INVENTION

Field of the Invention

2287483 This invention relates to an apparatus for forming a single-faced corrugated board by nipping a corrugating medium and a liner between a primary application means and a lower fluted roll so as to paste them together, and the apparatus is provided with a secondary application means which can compensate for the insufficiency in the bonding between the corrugating medium and the liner achieved by the primary application means.

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 e. ngage 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 - 2 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 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.

As a countermeasure for the problems described above, it is proposed to use an endless belt in place of the metallic press roll so as to nip the corrugating medium and the liner in cooperation with the lower fluted roll. More specifically, the endless belt which runs freely is disposed adjacent to the lower fluted roll, and the corrugating medium and the liner passing between the lower fluted roll and the endless belt are adapted to be nipped 3 - therebetween and pasted together by bringing the endless belt closer to the outer surface of the lower fluted roll. Thus, the use of the endless belt can prevent generation of great vibration and big noise and also formation of press marks on the single-faced corrugated board.

In such type of single facer, the corrugating medium is designed to run substantially along the axial central zones of the fluted rolls. Accordingly, if manufacturing of a single-faced corrugated board is continued for an extended period, the central portions of the fluted rolls along which the corrugating medium is fed wear to have reduced roll diameters. However, each axial end portion of the fluted rolls do not wear substantially, so that when the endless belt is brought closer to the lower fluted roll, the unworn end portions of the lower fluted roll prevent sufficient nipping at the central portion, resulting in insufficient bonding between the corrugating medium and the liner, disadvantageously.

Meanwhile, in the application mechanism provided with such endless belt, the corrugating medium and the liner are adapted to be nipped between the endless belt and the lower fluted roll by applying a predetermined pressure to the endless belt. In this case, the widthwise (axial direction of the lower fluted roll) tension of the endless belt tends to be stronger at each end portion and weaker at the central portion, so that it is difficult to apply tension evenly over the entire width of the belt. Namely, the nip pressure to be applied to the widthwise central portions of the corrugating medium and the liner is weak, so that secured bonding therebetween with a glue at such portion cannot be achieved, leading to insufficient bonding, disadvantageously.

In the case where the press roll, which is a metallic roll, - 4 is to be employed, hot steam is allowed to circulate through the internal portion of the press roll to heat the roll surface to a predetermined temperature so as to accelerate gelation of the starchy glue by applying sufficient heat to the glued portions of the corrugating medium and liner nipped between the press roll and the lower fluted roll, and thus the corrugating medium and the liner can securely be bonded to each other. However, in the case where the endless belt is employed, it is difficult to apply sufficient heat to the glued portions of the corrugating medium and liner along the zone where they are nipped between the belt and the lower fluted roll, and it can be pointed out that insufficient bonding due to the insufficiency in the heat quantity occurs particularly when a thick single-faced corrugated board is to be produced.

This invention is 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 a single facer, which can achieve secured bonding between a corrugating medium and a liner even in a structure which can minimize vibration or noise, as well as, press marks to be formed on the liner during the formation of a single-faced corrugated board sheet by pasting a corrugating medium with a liner.

SUMMARY OF THE INVENTION

In order to solve the problems described above and to attain the intended object suitably, it is one aspect of this invention to provide a single facer provided with an upper fluted roll having wavy flutes formed on the circumference thereof, a lower fluted roll also having wavy flutes formed on the circumference thereof 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 primary application means disposed on the circumference of the lower fluted roll and adjacent to the route of feeding the liner so as to run or rotate as the liner is fed, which brings the corrugating medium fed along the circumference of the lower fluted roll and the liner to be pasted therewith into press contact with the lower fluted roll; and a secondary application means also disposed on the circumference of the lower fluted roll and adjacent to the route feeding the liner and provided with a pressing member which can be moved closer to or farther from the lower fluted roll to be indirectly or directly brought into slide contact with the liner; wherein the corrugating medium fed along the circumference of the lower fluted roll and the liner to be pasted therewith are brought into press contact with the lower fluted roll by moving the pressing member closer to the lower fluted roll with the aid of urging means.

Further, in order to attain the intended object suitably, it is another aspect of this invention to provide a single provided with an upper fluted roll having wavy flutes formed on the circumference thereof, a lower fluted roll also having wavy flutes formed on the circumference thereof, 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 pressure chamber which partly covers the lower fluted roll so as to press the corrugating medium fed along the circumference of the lower fluted roll against the circumference of the roll with the aid of a pressurizing medium supplied into the chamber; a primary application means consisting of a plurality of rolls disposed to oppose to the lower fluted roll via the route of feeding the liner and an endless belt extended over the rolls, which brings the corrugating medium fed along the circumference of the lower fluted roll and the liner to be pasted therewith into press contact with the lower fluted roll; and a secondary application means disposed to oppose to the lower fluted roll via the endless belt and having a pressing member which can be moved closer to or farther from the lower fluted roll to be brought into slide contact with the liner; wherein the corrugating medium fed along the circumference of the lower fluted roll and the liner to be pasted therewith are brought into press contact with the lower fluted roll via the endless belt by moving the pressing member closer to the lower fluted roll with the aid of urging means.

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 a schematic cross-sectional view of a single facer according to a first embodiment of the invention; Fig. 2 shows schematically, in explanatory perspective view, the constitution of a secondary application mechanism 1 according to the first embodiment; Fig. 3 shows schematically a perspective view of the major section of the secondary application mechanism according to a first example; Fig. 4 shows schematically, in perspective view, the major section of the secondary application mechanism according to a second example; Fig. 5 shows schematically, in perspective view, the major section of the secondary application mechanism according to a third example; Fig. 6 shows schematically, in cross-sectional view, the major section of a single facer employing a secondary application mechanism according to a fourth example; Fig. 7 shows schematically, in cross-sectional view, the major section of a single facer employing a secondary application mechanism according to a fifth example; Fig. 8 shows schematically, in cross-sectional view, the major section of a single facer employing a secondary application mechanism according to a sixth example; Fig. 9 shows schematically, in cross-sectional view, the major section of a single facer employing a secondary application mechanism according to a seventh example; Fig. 10 shows schematically, in cross-sectional view, the single facer according to a second embodiment of the invention; Fig. 11 shows schematically, in cross-sectional view, the single facer according to a third embodiment of the 8 - invention; Fig. 12 shows schematically, in cross-sectional view, the single facer according to a fourth embodiment of the invention; Fig. 13 shows schematically, in perspective view, the major section of the secondary application mechanism according to an eighth example; Fig. 14 shows schematically, in cross-sectional view, the major section of the single facer employing the secondary application mechanism according to the eighth example; Fig. 15 shows schematically, in perspective view, the major section of the secondary application mechanism according to a ninth example; and Fig. 16 shows schematically, in cross-sectional view, the major section of the single facer employing the secondary application mechanism according to the ninth example.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Next, the single facer of the invention will now be described by way of preferred embodiments referring to the attached drawings. It should be noted here that the terms "upper fluted roll" and "lower fluted roll" are not necessarily used so as to define the vertical relationship. In this specification, the fluted roll to which a corrugating medium is first fed is appreciated to be the upper fluted roll; whereas the fluted roll on which the thus corrugated corrugating medium is pasted with a liner is appreciated to be the lower fluted roll.

(First embodiment) 9 - Fig. 1 shows schematically the constitution of the single facer according to a first embodiment of the invention. In a main frame 10, an upper fluted roll 12 having wavy flutes formed on the circumference thereof and a lower fluted roll 14 also having wavy flutes formed on the circumference thereof are rotatably supported. The rotary shaft of the upper fluted roll 12 locates diagonally above that of the lower fluted roll 14, and these rolls are designed to be engaged with each other by their flutes via a corrugating medium 16 (to be described later). A gluing mechanism 22 consisting of a gluing roll 18 and a doctor roll 20 is disposed immediately below the upper fluted roll 12 and diagonally below the lower fluted roll 14. The corrugating medium 16 is fed from a web feeding source (not shown) assumed to locate on the left side in Fig. 1 through a plurality of guide rolls 24 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 16 by passing through this zone. The thus corrugated corrugating medium 16 is glued at the crests of corrugation by the gluing mechanism 22 and then diverted upward along the circumference of the lower fluted roll 14. Meanwhile, a liner 26 is fed from a web feeding source (not shown) assumed to locate on the right side in Fig. I via a couple of roll-like preheaters 28 to the lower fluted roll 14 to be bonded to the glued crests of corrugation of the corrugating medium 16 and fed upward in such state. Incidentally, the lower fluted roll 14 has a plurality of circumferential grooves 14a defined at predetermined intervals along the axis thereof, and the corrugating medium 16 is designed to be sucked on the circumference of the lower fluted roll 14 through through holes (not shown) provided in the circumferential grooves 14a by allowing the inside of the roll 14 to assume negative pressure, so that the pasted webs can be fed stably. Further, hot steam is fed from a supply source (not shown) to circulate through the guide rolls 24 so that the corrugating medium 16 may be heated.

A primary application mechanism 30 for pasting the corrugating medium 16 and the liner 26 together in cooperation with the lower fluted roll 14 is disposed to oppose to the upper fluted roll 12 via the lower fluted roll 14. To describe more specifically, as shown in Fig. 1, a preheating roll 32 is rotatably disposed on the circumference of the lower fluted roll 14 in the main frame 10 at a lower position adjacent to the route of feeding the liner 26; and also a drive roll 34 is rotatably disposed at an upper position. Further, a tension roll 36 is rotatably disposed at a position spaced from the circumference of the lower fluted roll 14. An endless belt 38 is extended over these three rolls 32,34,36 so that it can run freely. The portion of the endless belt 38 locating between the preheating roll 32 and the drive roll 34 is designed to be brought closer to the circumference of the lower fluted roll 14, so that the corrugating medium 16 fed therealong and the liner 26 to be pasted with the medium 16 may be nipped between that portion of this endless belt 38 and the lower fluted roll 14.

Incidentally, the liner 26 passed the preheaters 38 is fed along the circumference of the preheating roll 32 via the endless belt 38 to the bonding zone where it is pasted with the corrugating medium 16. A seamless resin belt can suitably be used as the endless belt 38.

The preheating roll 32 is connected to a hot steam supply source (not shown), so that the roll surface may be heated to a predetermined temperature by circulating therethrough a hot steam. The liner 26 is designed to be heated via the endless belt 38 wound around the preheating roll 32 so as to apply heat to the glued portions of the corrugating medium 16 and the liner 26 and accelerate gelation of the starchy glue, achieving secured bonding between the corrugating medium 16 and the liner 26. Meanwhile, the drive roll 34, which is connected to a drive source (not shown) of the single facer, is rotated to drive the endless belt 38 to run at a predetermined speed in synchronization with the upper fluted roll 12 and the lower fluted roll 14. Further, the tension roll 36 is disposed in the main frame 10 to be shiftable in the radial direction of the lower fluted roll 14. The tension to be applied to the endless belt 38 is adapted to be adjusted by shifting the tension roll 36 closer to or farther from the lower fluted roll 14 with the aid of an urging means (not shown) such as a cylinder. Namely, contact pressure of the endless belt 38 against the corrugating medium 16 and the liner 26 fed along the circumference of the lower fluted roll 14 is adjusted by adjusting the tension of the endless belt 38.

A secondary application mechanism 40 is disposed to oppose to the lower fluted roll via the endless belt 38 abutted against the liner 26 fed along the circumference of the lower fluted roll 14. The secondary application mechanism 40 compensates for the insufficiency in the bonding between the corrugating medium 16 and the liner 26 achieved by the primary application mechanism 30. This secondary application mechanism 40 consists of a housing 42 having a U-shaped cross section and extended parallel to the lower fluted roll 14, and a pressing member 44 which is shiftable in the radial direction of the lower fluted roll 14 disposed in the housing 42, as shown in Figs. 1 and 2. This pressing member 44 is substantially as wide as the entire length of the lower fluted roll 14 and has a predetermined length in the circumferential direction of the roll 14. That surface of the pressing member 44 which opposes to the lower fluted roll 14 is arcuated after the circumference of the roll 14. A partition 46 is disposed in the housing 42, and elastically deformable tubes 48 are disposed between the inner bottom of the housing 42 and the bottom of the pressing member 44 in the upper space and the lower space defined by the partition 46 (on each side of the partition 46 in the circumferential direction of the lower fluted roll 14), respectively. The respective tubes 48 are extended over the entire width of the pressing member 44, and compressed air supply sources 50 are connected to the longitudinal end portions of the tubes 48 via valves 52, respectively. Namely, by feeding predetermined amounts of compressed air from the supply sources 50 to the corresponding tubes 48, respectively, the tubes 48 are expanded to bring the pressing member 44 into press contact with the lower fluted roll 14.

It should be noted here that compressed air can be fed to the upper and lower tubes 48 independent of each other, so that the contact pressure of the pressing member 44 to be applied to the lower fluted roll 14 can be changed in the circumferential direction. Further, as the material for the pressing member 44, those which are softer and have smaller coefficient of friction than the endless belt 38 can suitably be used, because the pressing member 44 is brought into slide contact with the rear surface of the endless belt 38.

(Operation of the first embodiment) Next, the operation of the single facer according to the first embodiment will be described.

In manufacturing a single-faced corrugated board, the tension roll 36 is shifted to be spaced from the lower fluted roll 14 to apply a predetermined tension to the endless belt 38, so that the corrugating medium 16 and liner 26 fed along the circumference of the lower fluted roll 14 can be brought into press contact with the roll surface by the portion of the endless belt 38 locating between the preheating roll 32 and the drive roll 34. Further, compressed air is supplied from the supply sources 50 to the tubes 48, respectively, to allow the pressing member 44 to move toward the lower fluted roll 14, and thus the endless belt 38 can be brought into press contact evenly with the liner 26 over the entire width of the endless belt 38.

The upper fluted roll 12 and the lower fluted roll 14 are driven to rotate, and also the drive roll 34 are driven to rotate and to run the endless belt 38. In this state, the corrugating medium 16, which is fed from the web feeding source via the guide rolls 24 to the engagement zone defined between the upper fluted roll 12 and the lower fluted roll 14, is allowed to have predetermined corrugation by passing this zone. The thus corrugated corrugating medium 16 is glued at the crests of corrugation by the gluing mechanism 22 and then diverted upward along the circumference of the lower fluted roll 14 (see Fig. 1).

Meanwhile, the liner 26 fed from the web feeding source via the preheaters 28 is further fed along the circumference of the preheating roll 32 via the endless belt 38 toward the bonding zone where it is pasted with the corrugating medium 16. This liner 26 is pressed against the crests of corrugation of the corrugating medium 26 as nipped over a predetermined length between the endless belt 38 and the lower fluted roll 14, and thus a single-faced corrugated board can be formed by pasting the corrugating medium 16 and the liner 26 together. In this case, since the endless belt 38 is brought into press contact with the corrugating medium 16 and liner 26 with even pressure over the entire width of the endless belt 38, secured bonding between the 14 - medium 16 and the liner 26 can be achieved over the entire width thereof. Further, since the roll surface is heated to a predetermined temperature by circulating hot steam through the preheating roll 32, the liner 26 can be heated via the endless belt 38 extended over the preheating roll 32 to apply heat to the glued portions of the corrugating medium 16 and accelerate gelation of the starchy glue, achieving secured bonding with the corrugating medium 16.

Incidentally, when a thick single-faced corrugated board is to be formed, as described above, the heat quantity to be applied to the glued portions of the corrugating medium 16 to be transferred from the endless belt 38 heated by the preheating roll 32 is not always sufficient. However, since the corrugating medium 16 and the liner 26 can securely be pressed together by the pressing member 44 in this embodiment, such constitution compensates for the insufficiency in the heat quantity to achieve secured bonding between the corrugating medium 16 and the liner 26. On the other hand, when a thin single-faced corrugated board is to be formed, since the corrugating medium 16 can securely be pasted with the liner 26 with the aid of the primary application mechanism 30 only, the compressed air may be exhausted from the tubes 48 so that the pressing member 44 may not apply any additional pressure to the corrugating medium 16 and liner 26. It is also possible to adjust the pressure to be applied by the pressing member 44 depending on the material etc. of the corrugating medium 16 and liner 26, as well as, the thickness thereof. It should be noted that when any load is applied to the pressing member 44 during the formation of the single-faced corrugated board, the tubes 48 undergo elastic deformation and absorb the load, preventing excessive load from being applied to the secondary application mechanism 40.

(Other examples of the secondary application mechanism) A r Fig. 3 shows a first example of the secondary application mechanism. The secondary application mechanism 40 consists of three separate blocks 54 aligned in the axial direction of the lower fluted roll 14. The constitution of each block 54 is basically exactly the same as that of the embodiment shown in Fig. 2. Namely, in this first example, since the pressure levels of the pressing members 44 in the respective blocks 54 of the secondary application mechanism 40 can be adjusted independent of one another, the nip pressure to be applied to the corrugating medium 16 and liner 26 between the lower fluted roll 14 and the respective pressing members 44 can be changed at three sections along the width of the webs. For example, when a thin single-faced corrugated board is to be formed, the secondary application mechanism 40 is not necessary. However, since the tension of the endless belt 38 is weaker at the central portion in terms of the width thereof, as described above, the center block 54 only may be used to apply an additional tension, and thus an even tension can be applied to the endless belt 38 over the entire width thereof. If the central portion of the lower fluted roll 14 is worn to have a reduced diameter after a single-faced corrugated board is formed over an extended period, the pressure levels to be applied by these three blocks 54 in the secondary application mechanism 40 may be adjusted independently, so that a nip pressure can be applied evenly to the corrugating medium 16 and liner 26 over the entire width thereof, preventing insufficient bonding between the corrugating medium 16 and the liner 26. It is recommended to position the ends of the pressing member 44 in each block 54 to coincide with the circumferential grooves 14a defined along the circumference of the lower fluted roll 14.

Fig. 4 shows a second example of the secondary application 16 - mechanism. The secondary application mechanism 40 is divided into smaller block 54, and the pressure levels of the pressing members 44 in the respective block 54 are designed to be adjusted independently (in Fig. 4, the housing 42 and the partition 46 are omitted; and the tubes 48 are shown partly). For example, the length of the pressing member 44 in each block 54 is set to 100 to 150 mm (a desired length), and the pressure to be applied to the corrugating medium 16 and liner 26 is adjusted finely on the order of 100 to 150 mm, so as to cope delicately with the change in the width of the corrugating medium 16 and liner 26 and also with the range of abrasion in the lower fluted roll 14. Namely, the corrugating medium 16 and the liner 26 are constantly nipped evenly over the entire width thereof between the lower fluted roll 14 and the endless belt 38 (pressing member 44) to achieve secured bonding between the corrugating medium 16 and the liner 26. Further, if the pressure to be applied by the pressing member 44 of the block 54 corresponding to the zone where the corrugating medium 16 and the liner 26 do not run is released, no unnecessary urging force is applied to the lower fluted roll 14 and the endless belt 38, preventing abrasion thereof.

Fig. 5 shows a third example of the secondary application mechanism. The secondary application mechanism 40 is disposed only at the axial central zone of the lower fluted roll 14. More specifically, the secondary application mechanism 40 compensates for the insufficient pressure of the endless belt 38, in the primary application mechanism 30, at the centralportion due to the reduced diameter of the lower fluted roll 14 by abrasion in this example, and thus an even nip pressure can be applied to the corrugating medium 16 and liner 26 over the entire width thereof. Further, the widthwise tension of the endless belt 38 in the primary application mechanism 30 can be made even by - 17 using the secondary application mechanism 40.

Fig. 6 shows a fourth example of the secondary application mechanism, in which a rod 56 applied to the bottom of the pressing member 44 is slidably inserted to the partition 46 and the bottom of the housing 42, and a compression spring 60 is interposed between the housing 42 and a regulating section 58 provided on the outer end portion of the rod 56 protruding from the housing 42. The compression spring 60 is designed to normally urge the pressing member 44 to be spaced away from the lower fluted roll 14, so that, when the compressed air is exhausted from the tubes 48, the pressing member 44 may be spaced from the endless belt 38 by the resilience of the compression spring 60. Thus, since the pressing member 44 can be retracted from the endless belt 38 when the pressing member 44 is not to be used, abrasion of the endless belt 38 and the pressing member 44 can be minimized, extending the lives thereof. Incidentally, a plurality of rods 56 and compression springs 60 are disposed at predetermined intervals along the width of the pressing member 44, so that the pressing member may entirely be spaced from the lower fluted roll 14.

Fig. 7 shows a fifth example of the secondary application mechanism, in which an air cylinder 62 is disposed on the outer bottom surface of the housing 42. A holder 64 slidably disposed in the housing 42 is connected to the piston rod 62a of the air cylinder 62 at the portion extended into the housing 42. A pressing member 44 is retractably disposed to the holder 64 via a plurality of rods 66 inserted thereto, and a compression spring 68 is fitted on each rod 66 locating between the pressing member 44 and the holder 64, so that the pressing member 44 may normally be urged to be spaced from the holder 64. Incidentally, the air cylinder 62 is operated under control to move the pressing member 44 via the holder 64 between an operational position where the pressing member 44 is brought closer to the lower fluted roll 14 and a retracted position where the pressing member 44 is spaced from the lower fluted roll 14. Namely, when the holder 64 and the pressing member 44 are shifted to the operational position by operating the air cylinder 62 so as to extend the piston rod 62a thereof, the pressing member 44 is brought into press contact with the lower fluted roll 14 via the endless belt 38, liner 26 and corrugating medium 16 under the resilience of the compression springs 68. If any load is applied to the pressing member 44 during formation of a single-faced corrugated board, the pressing member 44 retracts from the lower fluted roll 14 against the resilience of the compression spring 68 so that no excessive load may be applied to the secondary application mechanism 40.

Fig. 8 shows a sixth example of the secondary application mechanism, which has a bracket 70 fixed to the main frame 10, an air cylinder 72 pivotably supported at the bottom on the bracket 70 and a supporting plate 76 which is slidably disposed on the main frame 10 via guide rails 74 and connected to the piston rod 72a of the air cylinder 72. A pressing member 44 is retractably disposed to the supporting plate 76 via a plurality of rods 80 slidably inserted thereto, and a compression spring 82 is interposed between the pressing member 44 and the supporting plate 76, so that the pressing member 44 may normally be urged to be spaced from the supporting plate 76. Incidentally, the air cylinder 72 is operated under control to move the pressing member 44 between the operational position where the pressing member 44 is brought closer to the lower fluted roll 14 via the supporting plate 76 and the retracted position where the pressing member 44 is spaced from the lower fluted roll 14. Namely, when the supporting plate 76 and the pressing member 44 are shifted to the operational position by operating the air cylinder 72 so as to extend the piston rod 72a thereof, the pressing member 44 is brought into press contact with the lower fluted roll 14 via the endless belt 38, liner 26 and corrugating medium 16 under the resilience of the compression spring 82. If any load is applied to the pressing member 44 during formation of a single-faced corrugated board, the pressing member 44 retracts from the lower fluted roll 14 against the resilience of the compression spring 82, in the same manner as in the fourth example shown in Fig. 6, so that no excessive load may be applied to the secondary application mechanism 40. In this sixth example, the rod 80, compression spring 8 and air cylinder 72 are also disposed in plural numbers at predetermined intervals along the width of the pressing member 44.

In the fifth example shown in Fig. 7 and the sixth example shown in Fig. 8, it is also possible to constitute the secondary application mechanism 40 with a plurality of separate blocks aligned in the axial direction of the lower fluted roll 14, or to dispose the mechanism 40 only at the axial central portion of the lower fluted roll 14. It should be noted here that, when the secondary application mechanism 40 consists of a plurality of blocks 54, as shown in Fig. 3 or 4, it should be appreciated that the compression spring 68 or 82 and the cylinder 62 or 72 are disposed in each block. In the fifth and sixth examples, it is also possible to omit the compression springs 68, 82 and to allow the pressing member 44 to be brought into press contact with the lower fluted roll 14 under the operational force of the cylinders 62,72, respectively.

Fig. 9 shows a seventh example of the secondary application mechanism, which has a bracket 95 fixed onto the main frame 10, and a V-shaped pressing member 44 with one arm 44a - 20 thereof being pivotably supported on the bracket 95. The other arm 44b of this pressing member 44b is arcuated on the surface opposing to the lower fluted roll 14 after the circumferential curve of the roll 14. An adjust bolt 96 is screwed into the bracket 95, and a regulating section 97 is provided at a predetermined position of this bolt 96 extended from the bracket 95 toward the lower fluted roll 14, with a compression spring 98 being resiliently interposed between this regulating section 97 and the arm 44b. Namely, the arm 44b of the pressing member 44 is designed to be brought into press contact with the lower fluted roll 14 via the endless belt 38 in the primary application mechanism 30, liner 26 and corrugating medium 16 under the resilience of the compression spring 98. The pressure to be applied to the endless belt 38 is adjusted by moving the adjust bolt 96 with respect to the bracket 95. Incidentally, an extension spring 99 is interposed between the bracket 95 and the arm 44a of the pressing member 44, so that the arm 44b may be spaced from the endless belt 38 under the resilience of the extension spring 99, when the compression spring 98 is loosened.

In the seventh example shown in Fig. 9, it is also possible to constitute the secondary application mechanism 40 with a plurality of separate blocks aligned in the axial direction of the lower fluted roll 14, or to dispose the mechanism 40 only at the axial central portion of the lower fluted roll 14. It should be noted here that, when the secondary application mechanism 40 consists of a plurality of blocks, in other words when a plurality of pressing members 44 are to be disposed, the compression spring 98, adjust bolt 96 and the extension spring 99 shall be disposed in each pressing member 44. Thus, pressure can be applied to necessary portions of the endless belt 38 by adjusting each adjust bolt 96.

Figs. 13 and 14 show an eighth example of the secondary application mechanism, which has a stay 100 disposed on the main frame 10 and is extended parallel to the lower fluted roll 14, and a pair of brackets 101 disposed on the upper surface of the stay 100 to be spaced from each other in the longitudinal direction (axial direction of the lower fluted roll 14), with a support shaft 102 being extended between these brackets 101. A plurality of presser rolls 103 serving as the pressing members are rotatably fitted on this support shaft 102 in the axial direction. Further, pairs of supporting plates 104 are disposed, to oppose to and to be spaced from each other in the longitudinal direction, on the upper surface of the stay 100 at the positions farther from the lower fluted roll 14 than the presser rolls 103, respectively, and a pair of supporting arms 105 are disposed in guide grooves 104a defined in each pair of supporting plates 104 to be retractable with respect to the presser roll 103. A back-up roll 106 is rotatably supported between the free ends (end portions facing toward the presser roll 103) of the opposing supporting arms 105 disposed to each pair of opposing supporting palates 104. Incidentally, the backup rolls 106 are designed to have an arbitrary length so long as the presser rolls 103 can be brought into even contact with the lower fluted roll 14 over the entire length when the presser rolls 103 are brought into press contact with the lower fluted roll 14, as will be described later.

A common fitting plate 107 is disposed to the rear ends (the ends farther from the presser rolls 103) of all the supporting plates 104 disposed on the stay 100, and air cylinders 108 are disposed on this fitting plate 107 at the positions corresponding to the locations of the back-up rolls 106, with the piston rods 108a of the air cylinders 108 being fixed to connecting plates 109 connecting the respective pairs of supporting arms 105 (see Fig. 14).

- 22 Namely, the back-up rolls 106 can be brought into press contact with the corresponding presser rolls 103 by operating the air cylinders 108 to bring the supporting arms 105 closer to the presser rolls 103. in this process, the support shaft 102 on which the presser rolls 103 are fitted is deflected in the radial direction so as to bring the presser rolls 103 into press contact with the lower fluted roll 14 via the endless belt 38 in the primary application mechanism 30, liner 26 and corrugating medium 16. Then, the air cylinder 108 is operated in the negative direction to allow the back-up rolls 106 to retract from the presser rolls 103 and release pressure of the presser rolls 103 against the endless belt 38. It should be noted here that the amount of deflection in the support shaft 102 is very small so that the rotation of the presser rolls 103 on the support shaft 102 is not interfered thereby. Further, the pressure to be applied to the endless belt 38 by the presser rolls 103 is determined by the urging force of the air cylinders 108.

In the eighth example, since the plurality of presser rolls 103 arranged in the axial direction of the lower fluted roll 14 are urged independent of one another to apply pressure to the endless belt 38, pressure can selectively be applied to the necessary portions of the belt 38. Further, since the presser rolls 103 are rotated being driven by the running endless belt 38, abrasion due to the frictional resistance between these two members can be prevented. Incidentally, the diameter of the presser rolls 103 may be designed to be greater than in this example with respect to that of the lower fluted roll 14.

Figs. 15 and 16 shows a ninth example of the secondary application mechanism, which has a stay 100 fixed on the main frame 10 and extended parallel to the lower fluted roll 14 and a plurality of application devices 110 constituting the secondary application mechanism 40 disposed on the upper surface of the stay 100. Each application device 110 is provided with an L-shaped bracket 111 and a pair of guide rods 112, which are spaced from each other in the longitudinal direction of the stay 100, disposed on the bracket 111 to be slidable to and from the lower fluted roll 14. A holder 113 having a U-shaped plan view is fixed to the ends of the guide rods 112 protruding to the front side (facing the lower fluted roll) of the Lshaped bracket ill, and a presser roll 114 is rotatably supported, parallel to the lower fluted roll 14, by the holder 113. Further, an air cylinder 115 is disposed to the rear surface of the L-shaped bracket 111, with the piston rod 115a of the cylinder 115 being secured to the holder 113 (see Fig. 16). Namely, the presser roll 114 can be brought into press contact with the lower fluted roll 14 via the endless belt 38 in the primary application mechanism 30, liner 26 and corrugating medium 16 by operating the air cylinder 115 to bring the holder 113 closer to the lower fluted roll 14. If the air cylinder 115 is operated in the negative direction so as to allow the presser roll 114 to be spaced from the lower fluted roll 14, the pressure applied to the endless belt 38 by the presser roll 114 can be released. Incidentally, the pressure applied to the endless belt 38 by the presser roll 114 is decided by the urging force of the air cylinder 115. The reference number 116 shows a supporting member which is disposed on the L-shaped bracket 111 and supports the guide rods 112.

In this ninth example, since pressure is applied to the endless belt 38 by urging the plurality of presser rolls 114 arranged in the axial direction of the lower fluted roll 14 independent of one another, pressure can selectively be applied to the necessary portions of the belt 38. Further, since the presser rolls 114 are rotated being driven by the running endless belt 38, abrasion due to the frictional resistance between these two members can be prevented. Incidentally, in the ninth example, the positions of the presser rolls 114 in the adjacent two application devices 110 may be shifted up and down to secure narrower clearance to be formed between axial ends of these two presser rolls 114, and thus the zone where the presser rolls 114 are not brought into contact with the endless belt 38 can be minimized. Further, the diameter of the presser rolls 114 may be designed to be greater than in this example with respect to that of the lower fluted roll 14.

(Second embodiment) Fig. 10 shows schematically the constitution of the single facer according to a second embodiment of the invention, which is basically the same as that of the first embodiment described above. However, a pressure chamber 92 in which the gluing mechanism 22 is to be housed is disposed immediately below the upper fluted roll 12 and diagonally below the lower fluted roll 14. This pressure chamber 92 opens toward the upper fluted roll 12 and lower fluted roll 14, and the opening of the pressure chamber 92 and a seal roll 94 disposed immediately below the upper fluted roll 12 and lower fluted roll 14 is sealed to maintain the pressure chamber 92 in a substantially closed state. A compressed air is supplied from a supply source (not shown) to the pressure chamber 92 so that the internal pressure of the chamber 92 may be slightly higher (e.g. by 0.15 atm) than the atmospheric pressure. In this case, the outer surface of the lower fluted roll 14 locating in the pressure chamber 92 is assuming atmospheric pressure because of the circumferential grooves 14a defined at predetermined intervals in the axial direction. Accordingly, the corrugating medium 16 corrugated by passing between the A upper fluted roll 12 and the lower fluted roll 14 can stably be transported as it is sucked onto the roll surface due to the difference between the pressure of the pressure chamber 92 and the pressure on the outer surface of the lower fluted roll 14. The corrugating medium 16 diverted upward along the outer surface of the lower fluted roll 14 can securely be pasted with the liner 26 by the primary application mechanism 30 and the secondary application mechanism 40. Incidentally, if a hot compressed air is supplied into the pressure chamber 92, the corrugating medium 16 can be preheated.

(Third embodiment) Fig. 11 shows schematically the constitution of the single facer according to a third embodiment of the invention, and the difference is the arrangement of the upper fluted roll 12 and the lower fluted roll 14. Namely, the lower fluted roll 14 is rotatably supported immediately above the upper fluted roll 12 rotatably supported on the main frame 10, and the flutes of the upper fluted roll 12 are designed to be engageable with those of the lower fluted roll 14 via the corrugating medium 16. A gluing mechanism 22 consisting of a gluing roll 18 and a doctor roll 20 is disposed diagonally below the lower fluted roll 14. The corrugating medium 16 is fed from a web feeding source (not shown) assumed to locate on the right side in Fig. 11 via a guide roll 24 to the engagement zone defined between the upper fluted roll 12 and the lower fluted roll 14 to be corrugated as desired. The thus corrugated corrugating medium 16 is glued at the crests of corrugation by the gluing mechanism 22 and then diverted upward along the circumference of the lower fluted roll 14. Meanwhile, the liner 26 is fed from a web feeding source (not shown) assumed to locate on the left side in Fig. 11 via a preheater 28 to the lower fluted roll 14 to be pasted to the glued crests of corrugation of the corrugating medium 16 and forwarded upward in this state.

A primary application mechanism 30 of the same constitution as in the first embodiment described above is disposed above the lower fluted roll 14. Namely, an endless belt 38 is extended over three rolls 32,34,36, disposed rotatably on the main frame 10, so as to be able to run freely therealong, and the portion of the endless belt 38 locating between the preheating roll 32 and the drive roll 34 is brought closer to the circumference of the lower fluted roll 14, so that the corrugating medium 16 fed along the circumference of the lower fluted roll 14 and the liner to be pasted therewith may be nipped between that portion of the endless belt 38 and the lower fluted roll 14. Incidentally, the liner 26 passed the preheater 28 is fed along the circumference of the preheating roll 32 via the endless belt 38 to the bonding zone where it is pasted with the corrugating medium 16. Meanwhile, a secondary application mechanism 40 of the same constitution as in the first embodiment described above is disposed to oppose to the lower fluted roll 14 via the endless belt 36 which is abutted against the liner 26 fed along the circumference of the lower fluted roll 14. Accordingly, the corrugating medium 16 with a glue being applied to the crests of corrugation thereof by the gluing mechanism 22 and the liner 26 fed via the preheater 28 are securely bonded to each other by the primary application mechanism 30 and the secondary application mechanism 40, and thus a single-faced corrugated board can be formed.

It should be noted here that as the secondary application mechanism 40, any of the examples shown in Figs. 3 to 9, 13 and 15 can suitably be employed. Further, in the single facer according to the constitution shown in Fig. 11, the pressure chamber 92 in which the gluing mechanism 22 is to A X be housed may be provided so as to achieve stable transportation of the corrugating medium 16 as sucked onto the outer surface of the lower fluted roll 14 with the aid of the pressure in the pressure chamber 92.

(Fourth embodiment) Fig. 12 shows schematically the constitution of the single facer according to a fourth embodiment of the invention, which is of the same constitution as in the first embodiment, except that the constitution of the primary application mechanism 30 is different. Namely, a first resilient roll 84 is disposed on the circumference of the lower fluted roll 14 at an upper position adjacent to the route of feeding the liner 26, and the corrugating medium 16 fed along the circumference of the lower fluted roll 14 and the liner 26 to be pasted with the corrugating medium 16 are designed to be brought into resilient press contact with the lower fluted roll 14. Meanwhile, a second resilient roll 86 is disposed on the circumference of the lower fluted roll 14 at a lower position adjacent to the route of feeding the liner 26, and the corrugating medium 16 fed along the circumference of the lower fluted roll 14 and the liner 26 to be pasted with the corrugating medium 16 are also designed to be brought inLo resilient press contact with the lower fluted roll 14. Namely, the first resilient roll 84 and the second resilient roll 86 are disposed in a vertical relationship on the circumference of the lower fluted roll 14 and adjacent to the route of feeding the liner.

These two resilient rolls 84,86 are wound around metallic cylinders 88,89 to a predetermined thickness, respectively, and hot steam is designed to be supplied into the metallic cylinders 88,90 from a supply source not shown. Accordingly, the resilient rolls 84,86 are, for example, - 28 made of a heat-resistant silicon-containing synthetic rubber, so as to withstand the temperature of the hot steam supplied to the inside of the metallic cylinders 88,90. Incidentally, the positions of these resilient rolls 84,86 are designed to be adjusted so that they can apply appropriate contact pressure to the corrugating medium 16 fed along the circumference of the lower fluted roll 14 and the liner 26 to be pasted with the medium 16. The first resilient roll 84 and the second resilient roll 86 are of course rotated by the power transmitted from a suitable drive means (not shown) at a predetermined speed in synchronization with the upper fluted roll 12 and the lower fluted roll 14.

A secondary application mechanism 40 of the same constitution as in the first embodiment described above is disposed adjacent to the route of feeding the liner between the first resilient roll 84 and the second resilient roll 86. The pressing member 44 in this secondary application mechanism 40 is designed to be slidably abutted directly against the liner 26 so that the corrugating medium 16 and the liner 26 fed along the circumference of the lower fluted roll 14 can be brought into press contact with the lower fluted roll 14.

(Operation of the fourth embodiment) In the fourth embodiment shown in Fig. 12, since the corrugating medium 16 and the liner 26 fed along the circumference of the lower fluted roll 14 are brought into resilient contact with the lower fluted roll 14 under the actions of these two resilient rolls 84,86 disposed above and below the lower fluted roll 14, bonding of the corrugating medium 16 and the liner 26 with the glue can securely be achieved. Besides, the constitution employing the first and second resilient rolls 84,86 can notably it minimize vibration and noises 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 corrugated board.

It should be noted here that in the constitution where the resilient rolls 84,86 are wound around the metallic cylinders 88,90, the temperature of the hot steam supplied into the metallic cylinders 88,90 cannot directly be transferred to the glued portions of the corrugating medium 16, so that insufficient bonding due to the lack of heat quantity is liable to occur particularly when a thick single-faced corrugated board sheet is to be formed. However, in the fourth embodiment, since the corrugating medium 16 and liner 26 can be brought into press contact with the roll surface with the aid of the pressing member 44 of the secondary application mechanism 40, the lack of heat quantity can be made up for by the pressure of the pressing member 44 to achieve secured bonding at the glued portions.

(Variations) In the embodiments described above, while tubes, compression springs and air cylinders are used as the means for urging the pressing member, the present invention is not limited to them, but hydraulic cylinder, solenoid, means utilizing repulsion of magnet, etc. can suitably be employed. Further, it is also possible to divide the secondary application mechanism into blocks not only orthogonal to the axis of the lower fluted roll, as shown in Fig. 3, but also in the axial direction thereof, and to dispose a pressing member to each block and urge the respective blocks thereby independently under control. Incidentally, the number of blocks in the secondary application mechanism can arbitrarily be decided depending on the specifications of the single facer. The number of tube is not limited to two, but it may be one, three or more. As the fluid to be fed into the tubes, while air (gas) is used in the above embodiments, the fluid may be a liquid such as an oil, water, etc.

Incidentally, in the primary application mechanism according to the first embodiment of the invention, it is also possible to extend the endless belt across two rolls, i.e., the drive roll and the tension roll, so as to be able to run freely thereon, and also to supply a hot steam into these rolls. It is also possible to combine the primary application mechanism according to the fourth embodiment and the secondary application mechanism according to the example shown in any of Figs. 3 to 9, 13 and 15. Further, the first resilient roll constituting the primary application mechanism according to the fourth embodiment of the invention can be omitted.

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 embodiments and examples 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.

1

Claims

What is Claimed is:

1. A single facer provided with an upper fluted roll (12) having wavy flutes formed on the circumference thereof, a lower fluted roll (14) also having wavy flutes formed on the circumference thereof which engage with those of said upper fluted roll (12) and form a predetermined corrugation on a corrugating medium (16) to be passed between said upper fluted roll (12) and said lower fluted roll (14), and a gluing mechanism (22) for gluing the crests of the thus corrugated corrugating medium (16), in which a liner (26) is pasted onto the glued crests of said corrugating medium (16) so as to form a single-faced corrugated board; said single facer comprising: a primary application means (30) disposed on the circumference of said lower fluted roll (14) and adjacent to the route of feeding said liner (26) so as to run or rotate as said liner (26) is fed, which brings said corrugating medium (16) fed along the circumference of said lower fluted roll (14) and said liner (26) to be pasted therewith into press contact with said lower fluted roll (14); and a secondary application means (40) also disposed on the circumference of said lower fluted roll (14) and adjacent to the route feeding said liner (26) and provided with a pressing member (44,103,144) which can be moved closer to or farther from said lower fluted roll (14) to be indirectly or directly brought into slide contact with said liner (26); wherein said corrugating medium (16) fed along the circumference of said lower fluted roll (14) and said liner (26) to be pasted therewith are brought into press contact with said lower fluted roll (14) by moving said pressing member (44,103, 114) closer to said lower fluted roll (14) with the aid of urging means (48,50,68,82,98,108,115).

2. The single facer according to Claim 1, wherein said primary application means (30) consists of a plurality of rolls (32,34,36) and an endless belt extended over said rolls (32,34,36), and said corrugating medium (16) fed along the circumference of said lower fluted roll (14) and said liner (26) are adapted to be brought into press contact with said lower fluted roll (14) by said endless belt (38).

3. The single facer according to Claim 1, wherein said primary application means (30) consists of at least one rotatable resilient roll (86), and said corrugating medium (16) fed along the circumference of said lower fluted roll (14) and said liner (26) are adapted to be brought into press contact with said lower fluted roll (14) by said resilient roll (86).

4. A single facer provided with an upper fluted roll (12) having wavy flutes formed on the circumference thereof, a lower fluted roll (14) also having wavy flutes formed on the circumference thereof, which engage with those of said upper fluted roll (12) and form a predetermined corrugation on a corrugating medium (16) to be passed between said upper fluted roll (12) and said lower fluted roll (14) and a gluing mechanism (22) for gluing the crests of the thus corrugated corrugating medium (16), in which a liner (26) is pasted onto the glued crests of said corrugating medium (16) so as to form a singlefaced corrugated board; said single facer comprising: a pressure chamber (92) which partly covers said lower fluted roll (14) so as to press said corrugating medium (16) fed along the circumference of said lower fluted roll (14) against the circumference of said roll (14) with the aid of a pressurizing medium supplied into said chamber (92); a primary application means (30) consisting of a 33 plurality of rolls (32,34,36) disposed to oppose to said lower fluted roll (14) via the route of feeding said liner (26) and an endless belt extended over said rolls (32,34,36), which brings said corrugating medium (16) fed along the circumference of said lower fluted roll (14) and said liner (26) to be pasted therewith into press contact with said lower fluted roll (14); and a secondary application means (40) disposed to oppose to said lower fluted roll (14) via said endless belt (38) and having a pressing member (44,103,114) which can be moved closer to or farther from said lower fluted roll (14) to be brought into slide contact with said liner (26); wherein said corrugating medium (16) fed along the circumference of said lower fluted roll (14) and said liner (26) to be pasted therewith are brought into press contact with said lower fluted roll (14) via said endless belt (38) by moving said pressing member (44, 103,114) closer to said lower fluted roll (14) with the aid of urging means (48,50,68,82,98,108,115).

5. The single facer according to Claim 1 or 4, wherein said pressing member (44,103,114) are disposed in plural numbers in the axial direction of said lower fluted roll (14), and said respective pressing members (44, 103,114) are designed to be moved closer to or farther from said lower fluted roll (14) independent of one another.

6. The single facer according to any of Claims 1, 4 and 5, wherein the surface of said pressing member (44) opposing to said lower fluted roll (14) is arcuated after the circumferential curve of said roll (14), and said pressing member (44) can be moved farther from or closer to said lower fluted roll (14) by supplying or discharging a fluid to or from an elastically deformable tube.

7. The single facer according to any of Claims 1, 4 and 5, wherein the surface of said pressing member (44) opposing to said lower fluted roll (14) is arcuated after the circumferential curve of said roll (14), and said pressing member (44) is designed to bring said corrugating medium (16) and said liner (26) into press contact with said lower fluted roll (14) under the resilience of a spring (68,82,98).

8. A single facer subsantially as hereinbefore described with reference to the accompanying drawings.