GB2281921A - Apparatus for producing single-faced corrugated board sheets - Google Patents

Abstract

A single facer with minimized vibration and noise, as well as, reduced press marks, consists of an upper fluted roll (16), a lower fluted roll (18) which are inter-engaged to form a predetermined corrugation on a corrugating medium (20) passed therebetween; and a gluing mechanism (26) for gluing the crests of corrugation in medium (20); wherein medium (20) is pasted with a liner (66) at the glued crests to form a single-faced corrugated board sheet; characterized in that a pressure chamber (30) partially covers lower fluted roll (18) and allows a pressure medium to be fed to the chamber 30 to press the corrugating medium (20) against the circumference of lower fluted roll (18); and an endless belt (74), extended over a plurality of rolls (68, 70) disposed adjacent roll (18) to oppose thereto via the line of feeding the liner (66), in such a way that belt (74) can run freely on rolls (68, 70), and which brings liner (66) into press contact with corrugating medium (20) at the crests of corrugation. <IMAGE>

Description

APPARATUS FOR PRODUCING SINGLE-FACED CORRUGATED BOARD SHEETS BACKGROUND OF THE INVENTION Field of the Invention This invention relates to an apparatus for producing 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 producing a single-faced corrugated board sheet (so-called single facer), an upper fluted roll and a lower fluted roll each having 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 the corrugating medium and the liner which are the webs of the single-faced corrugated board sheet.

Namely, the corrugating medium is allowed to have a predetermined corrugation (flutes) as it is fed between the upper fluted roll and the lower fluted roll. A starchy glue is applied to the crests of corrugation 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 to form a single-faced corrugated board sheet.

The press roll employed in the conventional single facer is of a large-diameter metallic roll which is normally urged toward the lower fluted roll so as to apply a predetermined nip pressure to the corrugating medium and the 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 are formed horizontally on the surface of the liner in the thus formed single-faced corrugated board sheet corresponding to the pitch of the crests of the lower fluted roll, disadvantageously.

While the corrugating medium passed between the upper fluted roll and the lower fluted roll to be provided with a predetermined corrugation is designed to be fed stably as it is sucked onto the circumference of the lower fluted roll with the aid of the negative pressure secured in the circumferential grooves defined along the circumference of the lower fluted roll, the roll surface is inevitably cooled by the air being sucked therein in this sucking system. Therefore, in order to carry out pasting of the corrugating medium with the liner securely in a short time in this case, it is practiced to heat the liner beforehand to a predetermined temperature to accelerate solidification of the glue applied to the crests of the corrugating medium.Thus, it can be pointed out in the single facer employing such sucking system that the heat of the liner is deprived via the corrugating medium contacted with the circumference of the lower fluted roll, causing a great heat loss, disadvantageously.

This invention is proposed in view of the problems inherent in the single facer of the prior art and in order to overcome them successfully, and it is an objective of the invention to provide a single facer which enjoys reduced vibration and noise to be generated during formation of single-faced corrugated board sheets and also reduced heat loss.

SUMMARY OF THE INVENTION In order to solve the above problems and attain the intended objects successfully, this invention provides a single facer consisting of an upper fluted roll having flutes formed on the circumference thereof; a lower fluted roll, also having on the circumference thereof flutes which engage with those of the upper fluted roll and form a predetermined corrugation on a corrugating medium passed between the upper fluted roll and the lower fluted roll; and a gluing mechanism for gluing the crests of corrugation in the corrugating medium; wherein the corrugating medium is pasted with a liner at the glued crests of corrugation to form a single-faced corrugated board sheet; characterized in that the single facer is further provided with: a pressure chamber which partially covers the lower fluted roll and which presses the corrugating medium fed along the circumference of the lower fluted roll against the circumference with the aid of the pressure medium to be fed into the chamber; and an endless belt, which is extended over a plurality of rolls disposed adjacent to the lower fluted roll to oppose thereto via the line of feeding the liner, in such a way that the belt can run freely on the rolls, and which brings the liner into press contact with the corrugating medium at the crests of corrugation.

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 embodiment taken in conjunction with the accompanying drawings in which:: Fig. 1 shows schematically a cross-sectional view of the single facer according to a preferred embodiment of the invention; Fig. 2 shows schematically a front view of the single facer according to the preferred embodiment of the invention; Fig. 3 shows schematically the major section of the single facer according to the preferred embodiment of the invention; Fig. 4 shows in enlarged side view the three rolls disposed on split frames of the single facer according to the preferred embodiment of the invention; Fig. 5 shows in cross-section a guide roll in the single facer according to the preferred embodiment of the invention; Fig. 6 is a view explaining the state where a movable body in the single facer according to the preferred embodiment of the invention is moved to a second retracted position to separate the split frames and auxiliary frames from movable frames;; Fig. 7 shows schematically in cross section an adjusting mechanism for a seal roll in the single facer according to the preferred embodiment of the invention; Fig. 8 shows schematically in cross section the adjusting mechanism for a seal roll in the single facer according to the preferred embodiment of the invention; and Fig. 9 is a view illustrating a variation of an application mechanism in the single facer according to the preferred embodiment of the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The single facer according to this invention will now be described by way of a preferred embodiment referring to the attached drawings. Fig. 1 shows schematically the constitution of the single facer according to the preferred embodiment of the invention, in which a main body 14 of the single facer, consisting of a pair of opposing fixed frames 12 arranged to be spaced from each other (one on the drive side and the other on the operation side) on the line orthogonal to the direction of feeding a corrugating medium 20), is disposed on a base 10 installed on the floor of a plant, and an upper fluted roll 16 having flutes formed on the circumference thereof and a lower fluted roll 18 also having flutes formed on the circumference thereof are rotatably supported between these frames 12. The rotary shaft of the upper fluted roll 16 locates diagonally above that of the lower fluted roll 18, and the flutes of the upper fluted roll 16 are designed to be engageable with those of the lower fluted roll 18 via the corrugating medium 20. Meanwhile, a gluing mechanism 26 consisting of a gluing roll 22 and a doctor roll 24 is disposed immediately below the upper fluted roll 16 and diagonally below the lower fluted roll 18. The corrugating medium 20 is fed from a web feeding source (not shown) which is assumed to locate on the left side in Fig. 1 via a plurality of guide rolls 28 to the engagement zone defined between the upper fluted roll 16 and the lower fluted roll 18 to be provided with a predetermined corrugation by passing the engagement zone.The thus corrugated corrugating medium 20 is glued at the crests by the gluing mechanism 26 and then forwarded along the circumference of the lower fluted roll 18 to be diverted upward.

It should be noted here that a pressure chamber 30, in which the gluing mechanism 26 is to be housed, is defined immediately below the upper fluted roll 16 and diagonally below the lower fluted roll 18. The pressure chamber 30 is open toward the upper fluted roll 16 and the lower fluted roll 18. As shown in Fig. 3, a sealing member 34 is interposed between the upper portion of the opening of the pressure chamber 30 and the upper fluted roll 16 along the axis thereof, whereas another sealing member 34 is interposed between the lower portion of the opening of the pressure chamber 30 and a seal roll 32, which is disposed immediately below the lower fluted roll 18 and abutted against a preheating roll 70 (to be described later), along the axis of the seal roll 32.Meanwhile, a pair of side shielding members 31 (only one side shielding member is shown) for the pressure chamber 30 are abutted against the circumferences of the upper fluted roll 16, lower fluted roll 18, preheating roll 70 and seal roll 32 at both axial end portions, so that the pressure chamber 30 may be maintained substantially air tight. A compressed air is fed from a source (not shown) to the pressure chamber 30 so as to maintain the inside of the chamber to be slightly higher than the atmospheric pressure (e.g. by 0.15 atm).

In this case, the outer circumference of the lower fluted roll 18 facing the pressure chamber 30 is assuming the atmospheric pressure by virtue of the circumferential grooves defined axially at predetermined intervals.

Accordingly, the corrugating medium 20 corrugated by passing between the upper fluted roll 16 and the lower fluted roll 18 can be fed stably as pressed against the roll surface due to the difference between the pressure in the pressure chamber 30 and that on the circumference of the lower fluted roll 18.

Incidentally, the corrugating medium 20 can be preheated by feeding a high-temperature compressed air to the pressure chamber 30. Meanwhile, the gluing mechanism 26 is disposed to be slidable along the rails 36 laid on the bottom (base 10) of the pressure chamber 30, so that the gluing mechanism 26 can be carried out from the pressure chamber 30 along the rails 36 by opening the door 38 disposed on the left side of the pressure chamber 30 shown in Fig. 1.

A pair of guide rails 40 spaced from each other on the drive side and the operation side are laid on the base 10 at the portion extending rightward (at the position closer to the lower fluted roll 18) than the location of the main body 14, as shown in Fig. 1, and a movable body 44 is disposed on these guide rails 40 to be slidable via corresponding sliders 42. The movable body 44 consists of a pair of opposing movable frames 46 which are spaced from each other to the drive side and the operation side, split frames 50 fixed by a plurality of bolts 48 to the respective movable frames 46 to be splittable and auxiliary frames 52, with an application mechanism 54 being interposed between the opposing split frames 50 (see Fig.

4).

As shown in Fig. 2, a pair of hydraulic cylinders 56 (only one cylinder is shown) is disposed on the base 10 on the outer sides of the movable frames 46, and the piston rod 56a of each hydraulic cylinder 56 is connected to the bracket 58 disposed to the corresponding movable frame 46.

Accordingly, if these hydraulic cylinders 56 are synchronously operated in the positive or negative direction, the movable body 44 can be moved along the guide rails 40 to be closer to or farther from the main body 14.

Stoppers 60 protrude from those front end faces of the respective movable frames 46 which face the fixed frames 12, so that the movable body 44 may be located at the operation position (the position where the endless belt 74 of the application mechanism 54 is abutted against the lower fluted roll 18) by bringing these stoppers 60 into abutment against the positioning members 62 disposed to the corresponding fixed frames 12. Incidentally, the positions of the positioning members 62 are adapted to be adjustable, so that the operation position of the movable body 44 can suitably be adjusted.

The hydraulic cylinders 56 are designed to be able to position the movable body 44 at three positions: the operation position (as indicated by the solid line in Fig.

2) where the stoppers 60 are abutted against the positioning members 62; a first retracted position (as indicated by the dotted-and-dashed line in Fig. 2) where the movable body 44 is spaced from the main body 14 to allow replacement and maintenance of the lower fluted roll 18; and a second retracted position (see Fig. 6) where the movable body 44 is spaced from the main body 14 by the required distance so as to allow replacement of the endless belt 74 in the application mechanism 54. Incidentally, when the movable body 44 is positioned at the operation position, the movable body 44 is designed to be prevented from moving apart from the operation position under urging of the stoppers 60 by the hydraulic cylinders 56 such that they may be abutted against the positioning members 62 with a required pressure.

A couple of roll-like preheaters 64 are disposed between the movable frames 46, as shown in Fig. 3. The liner 66 fed from a web feeding source (not shown) assumed to be disposed on the right side in Fig. 3 is fed via the preheaters 64 to the lower fluted roll 18 to be pasted with the corrugating. medium 20 at the glued crests and fed upward.

A drive roll 68 and a preheating roll 70 are rotatably supported between the split frames 50 on the side closer to the lower fluted roll 18 to be spaced from each other along the tangential line of the lower fluted roll 18, as shown in Fig. 3. A tension roll 72 is also rotatably supported between the split frames 50 on the side farther from the lower fluted roll 18, and the endless belt 74 is extended over these three rolls 68, 70 and 72 supported between the split frames 50.The portion of the endless belt 74 locating between the drive roll 68 and the preheating roll 70 is designed to approach the circumference of the lower fluted roll 18, when the movable body 44 is moved closer to the main body 14 and positioned at the operation position, to nip the corrugating medium 20 being fed along the circumference of the lower fluted roll 18 and the liner 66, and thus they are pasted together between that portion of the endless belt 74 and the lower fluted roll 18.

Meanwhile, the preheating roll 70 locating lower than the drive roll 68 is interposed between the seal roll 32 and the lower fluted roll 18 and abutted via the endless belt 74 against these rolls 32,18. Thus, the opening of the pressure chamber 30 is blocked with the upper fluted roll 16, the lower fluted roll 18, the preheating roll 70 and the seal roll 32. Incidentally, a seamless resin belt can suitably be used as the endless belt 74.

In this constitution, since the seal roll 32 and the preheating roll 70 are abutted against each other via the endless belt 74, gaps corresponding to the thickness of the belt 74 are formed between these two rolls 32,70 at the respective axial end portions thereof where the belt 74 is not present. Since a compressed air is designed to be supplied constantly to the pressure chamber 30 so as to maintain a predetermined air pressure therein in view of leakage of the compressed air from the chamber 30, a great leakage of the compressed air through these gaps between these rolls 32,70 tends to cause elevation of the running cost due to the increased feed of the compressed air or reduction of air pressure in the chamber 30, resulting in the failure of securely press-contacting the corrugating medium 20 with the lower fluted roll 18.Therefore, it is recommended to fit sleeves which is as thick as the endless belt 74 on both end portions of the seal roll 32 so as not to form gaps between the seal roll 32 and the preheating roll 70. Incidentally, a U-shaped groove which is as wide as the endless belt 74 may otherwise be formed on the circumference of the seal roll 32. These sleeves or the groove also serves to regulate meandering (biasing in the axial direction of the roll) of the endless belt 74.

The tension of the endless belt 74 is designed to be adjustable such that it can press the corrugating medium 20 fed along the circumference of the lower fluted roll 18 and the liner 66 to be pasted therewith with an optimum contact pressure. Namely, supporting members 73 disposed to both axial end portions of the tension roll 72 are slidably fitted in the slots 50a defined in the respective split frames 50, so that the tension roll 72 may be movable with respect to the split frames 50 in the radial direction of the lower fluted roll 18. Meanwhile, a couple of hydraulic cylinders 76 are disposed on the outer sides of the split frames 50, with the piston rods thereof being connected to the corresponding supporting members 73.Accordingly, the tension roll 72 can be moved closer to or farther from the endless belt 74 by operating the pair of hydraulic cylinders 76 synchronously in the positive or negative direction, and thus the tension to be applied to the belt 74 can be adjusted. Incidentally, in the hydraulic cylinders 76 in this embodiment, the relative position of the tension roll 72 with respect to the endless belt 74 is designed to be shifted between three positions: a first position where a predetermined tension is applied to the endless belt 74 to achieve pasting of the corrugating medium 20 with the liner 66 securely; a second position where a very small tension is applied to the endless belt 74 extended over the three rolls 68,70,72 to be slackless; and a third position where the endless belt 74 is slacked enough to be pulled out axially from these three rolls 68,70,72.

Incidentally, the outer peripheral size of each split frame 50 is designed to be smaller than the inner peripheral size of the endless belt 74, so that the endless belt 74 extended over the three rolls 68,70,72 can axially be pulled out without separating the split frame 50.

A guide roll 78 abutted against the portion of the endless belt 74 locating between the drive roll 68 and the tension roll 72 is rotatably supported between the auxiliary frames 52. A pair of regulating members 80 are fitted on the circumference of this guide roll 78 to be spaced from each other by the distance slightly longer than the width of the endless belt 74, as shown in Fig. 5. These regulating members 80 serve to prevent biasing (meandering) of the endless belt 74 in the axial direction of the roll.

Incidentally, in this embodiment, meandering of the endless belt 74 is also prevented by disposing regulating members 80 to the tension roll 72 (see Fig. 4).

The drive roll is connected to a drive source (not shown) for the single facer via a universal joint 82, as shown in Fig. 4, to be rotated thereby, so as to drive the endless belt 74 to run at a predetermined speed synchronously with the upper fluted roll 16 and the lower fluted roll. It should be noted here that, since the drive roll 68 and the drive source are connected by the universal joint 82, the movable body 44 is allowed to be shifted closer to or farther from the main body 14. Meanwhile, the preheating roll 70 is connected to a high-temperature steam source (not shown), which distributes a high-temperature steam into the roll so as to heat the roll surface to a predetermined temperature. The liner 66 is heated via the endless belt 74 extended over the preheating roll 70 so that it can securely be bonded with the corrugating medium 20.

The position of the seal roll 32 is designed to be adjusted to be closer to or farther from the preheating roll 70 by the adjusting mechanisms disposed to the axial end portions of the seal roll 32, as shown in Figs. 7 and 8. Since these adjusting mechanisms are of the same constitution, only one mechanism will be described. Namely, Fig. 7 shows the adjusting mechanism disposed on the drive side of the seal roll 32, in which a supporting member 84 having an vertically elongated opening 84a stands on the base 10. A holder 86 fitted on the shaft 32a of the seal roll 32 is fitted in this elongated opening 84a to be ascendable therein. The holder 86 has a bevel 86a sloping at a required angle on the lower surface thereof, as shown in Fig. 7.A hydraulic cylinder 88 is disposed via a bracket 90 to the base 10 on the main body side, and a wedge 92 having on the upper surface a bevel 92a corresponding to the bevel 86a of the holder86 is connected to the piston rod 88a of the cylinder 88. As shown in Fig. 8, the wedge 92 is slidably fitted in the elongated opening 84a of the supporting member 84, so that the bevel 86a on the lower surface of the holder 86 may be abutted against the bevel 92a on the upper surface of the wedge 92. Accordingly, the seal roll 32 can be moved upward or downward by operating the hydraulic cylinders 88 of the respective adjusting mechanisms in the positive or negative direction to advance or retract the wedges 92 under engagement of these bevels 86a and 92a, and thus the clearance between the seal roll 32 and the preheating roll 70 can be adjusted.

Next, the function of the single facer according to the above-described embodiment will be described. Under operation of the single facer according to this embodiment, the internal pressure of the pressure chamber 30 is maintained to a necessary level under feeding of a compressed air thereto, and the corrugating medium 20 corrugated by passing between the upper fluted roll 16 and the lower fluted roll 18 is fed stably as pressed against the roll surface with the aid of the internal pressure of the pressure chamber 30. Accordingly, the crests of the corrugating medium 20 can smoothly be glued by the gluing mechanism 26 housed in the pressure chamber 30.

Incidentally, if a high-temperature compressed air is fed into the pressure chamber 30, the corrugating medium 20 can be preheated. Further, since the lower fluted roll 18 need not be provided with any suction mechanism for sucking the corrugating medium 20, it is also possible to distribute a high-temperature steam into the roll 18 to heat the roll surface to a predetermined temperature so as to heat the corrugating medium 20 wound around the lower fluted roll 18.

As shown in Fig. 1, the movable body 44, which is positioned at the operation position where the stoppers 60 are abutted against the positioning members 62 of the main body 14, is urged by the hydraulic cylinders 56 with a predetermined pressure. Meanwhile, the tension roll 72 is positioned at the first position by the hydraulic cylinders 76 to apply a predetermined tension to the endless belt 74.

Accordingly, the portion of the endless belt 74 locating between the drive roll 68 and the preheating roll 70 is brought closer to the lower fluted roll 18 to press the corrugating medium 20 being fed along the circumference of the lower fluted roll 18 and the liner 66 against the roll surface. Thus, the corrugating medium 20 and the liner 66 are nipped between the lower fluted roll 18 and the endless belt 74 over a predetermined length to be securely bonded at the glued portions.

As described above, since the corrugating medium 20 and the liner 66 are brought into press contact with each other by the endless belt 74 used in place of the press roll, the vibration and noise generated during formation of singlefaced corrugated board sheets, which have been of serious problems in the prior art, can notably be reduced, and the press marks formed on the liner of the single-faced corrugated board sheets can also be reduced. Besides, no heat loss attributable to the lower fluted roll 18 occurs, so that the corrugating medium 20 can efficiently be bonded with the liner 66.

Referring to the replacement, maintenance, etc. of the lower fluted roll 18, the hydraulic cylinders 56 are operated in the negative direction to move the movable body 44 to be farther from the main body 14 to the first retracted position, as indicated by the dotted-and-dashed line in Fig. 2. Thus, a necessary clearance can be secured between the lower fluted roll 18 and the application mechanism 54, and the operator can carry out replacement or maintenance of the roll 18 easily in a wide space in a short time. Meanwhile, the tension roll 72 of the application mechanism 54 is moved to the intermediate second position by operating the hydraulic cylinders 76 to release the tension applied to the endless belt 74 extended over the three rolls 68,70,72.Since the endless belt 74 can be maintained substantially tensionless when the single facer is not in operation, the life of the belt 74 can be extended.

Next, replacement of the endless belt 74 in the application mechanism 54 will be described. Since the endless belt 74 employed according to this embodiment is seamless, it must be pulled out axially from the three rolls 68,70,72.

Accordingly, after the movable body 44 is first moved to the second retracted position which is the farthest from the main body 14, the auxiliary frames 52 and the split frames 50 are separated from the movable frames 46, as shown in Fig. 6. The hydraulic cylinders 76 are also operated to retract the tension roll 72 and locate at the third position so as to slack the endless belt 74 to a state enough to allow pulling out thereof. Since the outer peripheral size of each split frame 50 is designed to be smaller than the inner peripheral size of the endless belt 74, the endless belt 74 can be pulled out axially from the three rolls 68,70,72 without separating the split frames 50 therefrom and replaced with a new belt.

Namely, since the movable body 44 equipped with the application means 54 for pressing the corrugating medium 20 and the liner 66 against the lower fluted roll 18 to paste them together is designed to be moved to be closer to or farther from the main body 14 equipped with the upper fluted roll 16 and the lower fluted roll 16, replacement and maintenance of the lower fluted roll 18 and the endless belt 74 in the application mechanism 54 can be carried out easily in a short time. Accordingly, the cycle times required for the replacement, maintenance, etc. can be reduced to improve production efficiency.

It should be noted that in the constitution employed in the embodiment shown in Fig. 1, the endless belt 74 in the application mechanism 54 is extended over the three rolls 68,70,72, and the tension roll 72 locating inner than the endless belt 74 is adapted to be moved closer to or farther from the endless belt 74. However, the present invention is not limited to such constitution. For example, as shown in the variation of Fig. 9, the endless belt 74 may be extended over the drive roll 68 and the preheating roll 70, and the tension roll located opposite to the lower fluted roll 18 and outer than the endless belt 74 may be moved closer to or farther from the endless belt 74 so as to adjust the tension thereof. Alternatively, the same regulating members 80 as disposed to the guide roll 78 and tension roll 70 may be disposed to the drive roll 68 and preheating roll 70.

Further, as the means for moving the movable body, a mechanism consisting of a motor and a ball screw or other means may suitably be selected and employed in place of the hydraulic cylinders. Meanwhile, the pressure medium fed to the pressure chamber is a normal-temperature or hightemperature compressed air in the embodiment exemplified above. However, a normal-temperature or high-temperature dry stem may be used instead.

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 embodiment and variations 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.

Claims (6)

What is Claimed is:

1. A single facer consisting of an upper fluted roll (16) having flutes formed on the circumference thereof; a lower fluted roll (18), also having on the circumference thereof flutes which are engaged with those of said upper fluted roll (16) and form a predetermined corrugation on a corrugating medium (20) passed between said upper fluted roll (16) and said lower fluted roll (18); and a gluing mechanism (26) for gluing the crests of corrugation in said corrugating medium (20); in which said corrugating medium (20) is pasted with a liner (66) at said glued crests of corrugation to form a single-faced corrugated board sheet; characterized in that said single facer is further provided with: a pressure chamber (30) which partially covers said lower fluted roll (18) and which presses said corrugating medium (20) fed along the circumference of said lower fluted roll (18) against said circumference with the aid of the pressure medium to be fed into said chamber (30); and an endless belt (74), which is extended over a plurality of rolls (68,70) disposed adjacent to said lower fluted roll (18) to oppose thereto via the line of feeding said liner (66), in such a way that said belt (74) can run freely on said rolls (68,70), and which brings said liner (66) into press contact with said corrugating medium (20) at the crests of corrugation.

2. The single facer according to Claim 1, wherein said gluing mechanism (26) is retractably housed in said pressure chamber (30).

3. The single facer according to Claim 1 or 2, wherein a couple of sealing members (34) and a couple of shielding members (31) are interposed between the portion of the opening of said pressure chamber (30), which is open toward said lower fluted roll (18), and the respective members (16,18,70,32) which oppose to said opening, in such a way that said sealing member (34) and said shieldinq member (31) may be rotated under sliding on said members (16, 18,70,32) , whereby to maintain said pressure chamber (30) substantially air tight.

4. The single facer according to Claim 1, 2 or 3, wherein a predetermined tension is applied to said endless belt (74) by the tension roll (70).

5. The single facer according to Claim 1, 2 or 3, wherein said endless belt (74) is extended over three rolls (68,70,72) to be driven to run freely thereby.

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