GB2304125A

GB2304125A - Corrugator:single facer:material bonding

Info

Publication number: GB2304125A
Application number: GB9523022A
Authority: GB
Inventors: Eiichi Isowa
Original assignee: Isowa KK
Current assignee: Isowa KK
Priority date: 1995-08-11
Filing date: 1995-11-09
Publication date: 1997-03-12
Also published as: FR2737680A1; ES2121530A1; FR2737680B1; IT1283744B1; GB9523022D0; ES2121530B1; DE19546767A1; TW325438B; ITMI960748A0; ITMI960748A1

Description

1 SINGLE FACER IN CORRUGATOR

BACKGROUND OF THE INVENTION

Field of the Invention

2304125 This invention relates to an apparatus for bonding a corrugating medium with a liner by nipping them together with at least two press rolls and a second fluted roll to form a single-faced corrugated board.

Description of the Related Art

In the apparatus for forming a single-faced corrugated board (hereinafter referred to as single facer), a first fluted roll and a second fluted roll each having wavy flutes formed on the"eircumference 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 second fluted roll via a corrugating medium and a liner which are the webs of the single-faced corrugated board. Namely, the corrugating medium, which is fed between the first fluted roll and the second 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 opposite side with respect to the corrugating medium via the press roll is pressed against the glued crests of the corrugating medium, between the press roll and the second fluted roll, to be pasted together and form a single-faced corrugated board.

The press roll employed in the conventional single facer is of a largediameter metallic roll which is normally urged toward the second fluted roll so as to apply a predetermined nip pressure to the corrugating medium glued at the crests and the liner passing between these rolls and form a singlefaced corrugated board. Since flutes consisting of alternative repetition of crests and troughs are formed continuously at a predetermined pitch on the circumference of the second fluted roll, the distance between the rotation 2 center of the second fluted roll and that of the press roll shift slightly as the point of press contact of the second fluted roll 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 or farther relative to 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, such relative periodical shift of the rotation centers of these rolls causes the crests of the second fluted roll to hit the surface of the press roll to apply impact periodically (so-called the hammering phenomenon). Accordingly, linear press marks corresponding to the pitch of the crests of the second fluted roll are formed crosswise on the surface of the liner in the thus formed singlefaced corrugated board, disadvantageously.

The problems described above are-brought about by the great nip pressure between the second fluted roll and the press roll, which is required to nip the corrugating medium and the liner at one line contact portion between the second fluted roll and the press roll opposing each other and to paste them together. As a countermeasure for the problems described above, it is proposed to arrange two press rolls adjacent to the second fluted roll to be spaced from each other in the circumferential direction of the second fluted roll and to paste the corrugating medium with the liner by nipping them together between the second fluted roll and the press rolls. Specifically, the corrugating medium and the liner are designed to be subjected to initial bonding by the first press roll locating at an upstream position with respect to the direction of feeding the corrugating medium being fed along the circumference of the second fluted roll, followed by complete bonding by the second press roll locating at a downstream position with respect to the direction of feeding the corrugating medium. According to this constitution, the total nip pressure of these two press rolls may be equal to the nip pressure of one press roll as employed in the prior art, so that the nip pressure of each press roll can be set at a small level, and thus not only vibration and noises to be generated by the great nip pressure between the second fluted roll and each press roll can be reduced, but also the resulting single-faced corrugated board is prevented from having press marks.

3 In the single facer described above, the glue bonding the corrugating medium and liner together by the initial bonding over the first press roll is not yet solidified (water content is not fully evaporated) but is semisolidified to assume a gelatinous state. In such state, the corrugating medium and liner are passed over the second press roll to allow the semisolidified (semidried) glue to be fully solidified.

In this step, if the peripheral speed of the second press roll is lower than that of the second fluted roll, the initially bonded corrugating medium and liner become redundant between the first press roll and the second press roll, inducing failure in the bondage between them and feeding failure, disadvantageously. Meanwhile, if the peripheral speed of the second press roll is higher than that of the second fluted roll, the bonded portions of the corrugating medium and the liner are rubbed via the liner at the time point when the corrugating medium and.the liner underwent the initial bonding are about to be solidified, that is when they are nipped between the second press roll and the second fluted roll, to be prevented from being adhered to each other by the solidifying glue, causing bonding failure, disadvantageously. In other words, the most important thing for achieving bonding between the corrugating medium and the liner securely and neatly is to allow the second press roll and the second fluted roll are rotated at the same peripheral speed.

SUMMARY OF THE INVENTION

L.

The present invention was proposed in view of the problems inherent in the prior art, as described above, and in order to solve them successfully, and it is an objective of this invention to provide a highly economical single facer which can reduce not only vibration or noises to be generated when a singlefaced corrugated board is formed by pasting a corrugating medium with a liner but also press marks to be formed on the liner, and which can ensure bonding between the corrugating medium and the liner.

In order to solve the above-described problems and attain the intended object, one aspect afthis invention is to provide a single facer, containing a first fluted roll having wavy flutes formed on the circumference; a second fluted 4 roll, also having wavy flutes formed on the circumference to be engageable with the flutes of the first fluted roll, for imparting a required corrugation to a corrugating medium to be passed between the two rolls; a gluing mechanism for gluing crests of the thus corrugated corrugating medium; and a plurality of press rolls, located on the cixcumference of the second fluted roll and adjacent to the route of feeding a liner to be pasted with the corrugating medium, for bringing the liner into press contact with the corrugating medium fed along the circumference of the second fluted roll to paste them together; the single facer comprising a drive means for rotating at least one roll of the press rolls, locating on the downstream end with respect to the direction of feeding the corrugating medium and liner, constantly at the same peripheral speed as that of the second fluted roll.

Another aspect of this invention for attaining the intended object is to provide a single facer, containing- a first fluted roll having wavy flutes formed on the circumference; a second fluted roll, also having wavy flutes formed on the circumference to be engageable with the flutes of the first fluted roll, for imparting a required corrugation to a corrugating medium to be passed between the two rolls; a gluing mechanism for gluing crests of the thus corrugated corrugating medium; and at least two press rolls, located on the circumference of the second fluted roll and adjacent to the route of feeding a liner to be pasted with the corrugating medium, for bringing the liner into press contact with the corrugating medium fed along the circumference of the second fluted roll to paste them together; the single facer comprising a drive means for variably controlling the peripheral speed of the feed-out press roU locating on the downstream side with respect to the direction of feeding the corrugating medium and liner; a detection means for detecting the peripheral speed of the feed-out press roll.; a detection means for detecting the peripheral speed of the second fluted roll; and a control means for controlling the drive means such that the feed-out press ron may be rotated constantly at the same peripheral speed as that of the second fluted roll based on the values detected by the detection means.

Another aspect of this invention for attaining the intended object is to provide a single facer, containing a first fluted roll having wavy flutes formed on the circumference; a second fluted roll, also having wavy flutes formed on the circumference to be engageable with the flutes of the first fluted roll, for imparting a required corrugation to a corrugating medium to be passed between the two rolls; a gluing mechanism for gluing crests of the thus corrugated corrugating medium; and a plurality of press rolls, located on the circumference of the second fluted roll and adjacent to the route of feeding a liner to be pasted with the corrugating medium, for bringing the liner into press contact with the corrugating medium fed along the circumference of the second fluted roll to paste them together; wherein the feed-out press roll of the press rolls, locating on the downstream side with respect to the direction of feeding the corrugating medium and liner, is designed to be rotated at a peripheral speed greater than that of the press roll locating on the upstream side with respect to the direction of feeding the corrugating medium and liner.

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 constitutional view of a single facer according to a first embodiment of the invention; Fig. 2 shows a control block diagram of the single facer according to the first embodiment; Fig. 3 shows schematically a constitutional view of a single facer according to a second embodiment of the invention; Fig. 4 shows a control block diagram of the single facer according to the second embodiment; Fig. 5 shows an explanatory view of a modification of driving means for the first press roll and the second press roll; and 6 Fig. 6 shows an explanatory view of a modification of driving means for the first press roll and the second press roll.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The single facer according to this invention will now be described by way of preferred embodiments, referring to the attached drawings.

(First embodiment) Fig. 1 shows schematically a constitutional view of a single facer according to a first embodiment of the invention. In the single facer, a first fluted roll 12 having wavy flutes formed on the circumference and a second fluted roll 14 also having flutes formed on the -circumference are rotatably supported on a frame main body 10 which are spaced from each other at a predetermined distance. The rotary shaft of the first fluted roll 12 locates diagonally below that of the second fluted roll 14, and the flutes of the first fluted roll 12 are designed to be engageable with those of the second fluted roll 14 via a corrugating medium 16 (to be described later). Meanwhile, a gluing mechanism 22 consisting of a gluing roll 18 and a doctor roll 20 is disposed immediately below the first fluted roll 12 and diagonally below the second fluted roll 14. A corrugating medium 16 is fed from a web feeding source (not shown) assumed to locate on the left side in Fig. 1, via a plurality of guide rolls 24, to the engagement zone defined between the first fluted roll 12 and the second fluted roll 14 to be corrugated as required by passing the engagement zone. The thus corrugated corrugating medium 16 is glued at the crests by the gluing mechanism 22 and then diverted upward along the circumference of the second fluted roll 14. Meanwhile, a liner 26 is fed from another web feeding source (not shown) assumed to locate on the left side in Fig. 1 via a pair of roll-like preheaters 28, which are steam- heated, to the second fluted roll 14 to be pasted with the glued crests of the corrugating medium 16 and fed as such upward. The corrugating medium 16 is also designed to be heated by hot steam distributed from a supply source (not shown) into the guide roll 24.

7 The gluing mechanism 22 is housed in a substantially dosed pressure chamber 32 which is opening toward the first fluted roll 12 and the second fluted roll 14, and which is sealed between the opening and the first fluted roll 12 and between the opening and a seal roll 30 locating immediately below the second fluted roll 14. Compressed air is supplied into this pressure chamber 32 from a supply source (not shown) so that the internal pressure of the pressure chamber 32 may be slightly higher (e.g. by 0.15 atm.) than the atmospheric pressure. Circumferential grooves (not shown) are defined on the surface of the second fluted roll 14, so that the outer surface of the roll 14 facing the pressure chamber 32 may assume the atmospheric pressure. Accordingly, the corrugating medium 16 corrugated by passing between the first and second fluted rolls 12,14 is stably fed as pressed against the roll surface by the difference between the internal pressure of the pressure chamber 32 and the pressure on the outer surface of the second fluted roll 14. The cbrrugating medium 16 diverted upward along the outer surface of the second fluted roll 14 is then securely pasted with the liner 26 by two press rolls 34,36 (to be described later).

A pair of press rolls 34,36 are arranged across the second fluted roll 14 from the first fluted roll 12 to be spaced from each other in the circumferential direction of the second fluted roll 14. These press rolls 34,36 cooperate with the second fluted roll 14 to paste the corrugating medium 16 with the liner 26. Specifically, as shown in Fig. 1, a first press roll 34 is rotatably located on the circumference of the second fluted roll 14 and at a lower position adjacent to the route of feeding the liner 26, so that the corrugating medium 16 fed along the circumference of the second fluted roll 14 and the liner 26 to be pasted therewith may be pressed against the second fluted roll 14. Meanwhile, a donwnstream. second press roll 36 is rotatably located to be in contact with the circumference of the second fluted roll 14 and at an upper position adjacent to the route of feeding the liner 26, so that the corrugating medium 16 being fed along the circumference of the second fluted roll 14 and the liner 26 to be pasted therewith may be also pressed against the second fluted roll 14. In other words, the first press roll 34 and the second press roll 36 are arranged in a vertical relationship on the circumference of the second fluted roll 14 and adjacent to the route of feeding the liner. Meanwhile, the liner 26 passed over the preheaters 28 is first fed along the 8 circumference of the upstream first press roll 34 to the bonding zone where it is pasted with the corrugating medium 16 and then to the bonding zone defined between the feed-out second press roll 36 and the second fluted roll 14. Incidentally, the first press roll 34 is designed to be abutted against the seal roll 30 so as to maintain the pressure chamber 32 closed.

The first press roll 34 is rotatably supported on the frame main body 10 to be driven by the second fluted roll 14 brought into press contact with the roll 34 via the corrugating medium 16 and the liner 26 to rotate at the same peripheral speed.. Meanwhile, the second press roll 36 is designed to be positively driven by a main motor M (to be described later) to rotate at the same peripheral speed as that of the second fluted roll 14. These press rolls 34,36 are connected to a hot steam supply source (not shown) to allow hot steam to be distributed through these rolls and heat the roll surfaces to a predetermined temperature. The-liner 26 brought into contact with the press rolls 34,36 is thus heated to apply heat to the glue-bonding portions of the corrugating medium 16 and the liner 26 and accelerate gelation of the starchy glue, ensuring bonding between the corrugating medium 16 and the liner 26. These press rolls 34,36 are designed to be shiftable toward and away from the second fluted roll 14 by independent eccentric mechanisms (not shown), respectively, to apply optimum nip pressure depending on the thickness of the corrugating medium 16 or of the liner 26, as well as the kind, material, etc. thereof. Further, the first press roll 34 may be connected by means of gears etc. to the driving system of the second fluted roll 14 to be positively driven at the same peripheral speed as that of the roll 14.

As shown in Fig. 2, control signals generated from a production speed commander 38 are fed via a drive unit DU to the main motor M for rotationally driving the second fluted roll 14 to control the second fluted roll 14 to be rotated at a peripheral speed corresponding to the speed of feeding the corrugating medium 16 and liner 26 (line speed). A speed detector TG l is connected as a detection means to this main motor M to detect rotational speed of the motor M, i.e. the peripheral speed of the second fluted roll 14 and input the detected speed value to a speed ratio station 40 serving as a control means. Further, a powder clutch PC is connected as a drive means via a suitable power diverging means (not shown) to the main motor M, so 9 that the power of the main motor M may be transmitted via the dutch PC to the second press roll 36.

The second press roll 36 is connected to a speed detector TG2 for detecting peripheral speed of the roll 36. The peripheral speed of the second press roll 36 detected by the speed detector TG2 is input to the speed ratio station 40, where the peripheral speed of the second fluted roll 14 detected by the speed detector TG 1 is compared with that of the second press roll 36 detected by -the speed detector TG2 to control and shift the powder clutch PC so as to allow the second press roll 36 and the second fluted roll 14 to rotate constantly at the same peripheral speed. More specifically, when the peripheral speed of the second press roll 36 is lower than that of the second fluted roll 14, the powder clutch PC is controlled to be shifted to the accelerating side via an amplifier A to accelerate rotation of the second press roll 36. On the contrary, when the peripheral speed of the second press roll 36 is higher than that of the second fluted roll 14, the powder clutch PC is controlled to be shifted to the decelerating side via the amplifier A to decelerate rotation of the second press roll 36. Thus, the second press roll 36 and the second fluted roll 14 can be allowed to rotate at the same peripheral speed.

(Action of the first embodiment) Next, action of the single facer according to the first embodiment of the invention will be described. When a single-faced corrugated board is to be produced, the first press roll 34 and the second press roll 36 are moved closer to the second fluted roll 14 to press the corrugating medium 16 fed along the circumference of the second fluted roll 14 and the liner 26 to be pasted therewith against the surface of the second fluted roll 14. The nip pressure of the first press roll 34 and that of the second press roll 36 are set at low levels compared with the case where one press roll is employed like in the prior art, so that the total nip pressure of these two rolls may be substantially equal to the nip pressure of the single press roll of the prior art.

The first and second fluted rolls 12,14 are rotationally driven, and also the second press roll 36 is rotationally driven by the power transmitted from the main motor M via the powder clutch PC. In this state, the corrugating 1 () medium 16 fed from the web feeding source through the guide rolls 24 to the engagement zone defined between the first fluted roll 12 and the second fluted roll 14 is corrugated as required when it passes through the 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 second fluted roll 14 (see Fig. 1).

Meanwhile, the liner 26 supplied from the web feeding source through the preheaters 28 is fed to the bonding zone defined between the second fluted roll 14 and the first press roll 34. The liner 26 is pressed against the crests of the corrugating medium 16 as nipped between the first press roll 34 and the second fluted roll 14 to undergo initial bonding. Since the first press roll 34 is rotationally driven by the second fluted roll 14 brought into press contact with the roll 34 via the corrugating medium 16 and the liner 26 to rotate at the same peripheral spetd as that of the roll 14, there is caused no bonding failure attributed to the difference in the peripheral speed levels of these two rolls 14,34.

The corrugating medium 16 and liner 26 underwent the initial bonding as nipped between the second fluted roll 14 and the first press roll 34 is then fed to the bonding zone defined between the second fluted roll 14 and the second press roll 36. The corrugating medium 16 and the liner 26 fed to the bonding zone are fully adhered to provide a single-faced corrugated board. In this process, the speed ratio station 40 compares the peripheral speed of the second press roll 36 detected by the speed detector TG2 with that of the second fluted roll 14 detected by the speed detector TG1 to control and shift the powder clutch PC, when the peripheral speed of the second press ron 36 is lower than that of the second fluted roll 14, to the accelerating side via the amplifier A to accelerate rotation of the second press roll 36 to the speed level of the second fluted roll 14. On the contrary, when the peripheral speed of the second press roll 36 detected by the speed detector TG2 is higher than that of the second fluted roll 14, the powder clutch PC is controlled to be shifted to the decelerating side via the amplifier A to decelerate rotation of the second press roll 36 to the speed level of the second fluted roll 14. More specifically, since the second press roll 36 is constantly controlled to rotate at the same peripheral speed as that of the second fluted roll 14, bonding 11 failure attributable to such difference in the peripheral speed levels of the second fluted roll 14 and of the second Press roll 36 is inhibited to ensure bonding between the corrugating medium 16 and the liner 26.

As described above, since the corrugating medium 16 and the liner 26 are pasted together with the aid of two press rolls 34,36 according to the first embodiment, the nip pressure of the press rolls 34,36 can be set at low levels, and thus not only vibration and noises to be generated during formation of a single-faced corrugated board but also press marks to be formed on the liner of the single-faced corrugated board can be reduced. Besides, the feed-out second press roll 36 locating on the downstream side with respect to the direction of feeding the liner 26 is constantly controlled to rotate at the same peripheral speed as that of the second fluted roll 14, so that it does not happen that the bonding portions of the corrugating medium 16 and the liner 26 are rubbed or that they are puRed upstream or downstream to be separated from each other, ensuring glue-bonding of the corrugating medium 16 and the liner 26.

(Second embodiment) Fig. 3 shows schematically a constitutional view of a single facer according to a second embodiment of the invention. What is different from the first embodiment is the positional relationship of fluted rolls 12,14. Specifically, a second fluted roll 14 is rotatably supported diagonally above a first fluted roll 12 rotatably supported on the frame main body 10, wavy flutes of the former roll are designed to be engaged with those of the latter roll via a corrugating medium 16. A gluing mechanism 22 housed in a pressure chamber 32 is located beside the first fluted roll 12 and diagonally below the second 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. 3 through a plurality of guide rolls 24 to the engagement zone defined between the first fluted roll 12 and the second fluted roll 14 to be corrugated as required by passing through the zone. The thus corrugated corrugating medium 16 is glued at the crests by the gluing mechanism 22 and then diverted upward along the circumference of the second fluted roll 14. Meanwhile, a liner 26 is fed from a web feeding source (not shown) assumed to locate on the left 12 side in Fig. 3 via a plurality of preheaters 28 to the second fluted roll 14 to be pasted with the glued crests of the corrugating medium 16 and fed as such upward.

A pair of press rolls 34,36 are disposed above the second fluted roll 14 to be spaced from each other in the circumferential direction of the second fluted roll 14. Specifically, a feed-in first press roll 34 is rotatably located at an upstream position (on the left side m Fig. 3) with respect to the direction of feeding the corrugating medium 16 being fed along the circumference of the second fluted roll 14; whereas a feed- out second press roll 36 is rotatably disposed at a downstream position (on the right side in Fig. 3). Thus, the corrugating medium 16 fed along the circumference of the second fluted roll 14 and the liner 26 to be pasted therewith are adapted to be nipped between each of the press rolls 34,36 and the second fluted roll 14 to paste them together. The first press roll 34-is.designed to be driven by the second fluted roll 14 abutted against the roll 34 and to rotate at the same peripheral speed as that of the roll 14. Incidentally, since the peripheral speed of the first press roll 34 may be substantially the same as that of the second fluted roll 14, it is also possible to positively drive the first press roll 34 by means of gears such that the roll 34 may be rotated substantially at the same peripheral speed as that of the second fluted roll 14. The second press roll 36 is designed to be positively driven by the main motor M to rotate at the same peripheral speed as that of the second fluted roll 14.

The control system in the second embodiment is the same as that of the first embodiment, and control signals generated from a production speed commander 38 are fed via a drive unit DU to the main motor M for rotationally driving the second flute d roll 14, as shown in Fig. 4, to control the second fluted roll 14 to be rotated at a peripheral speed corresponding to the speed of feeding the corrugating medium 16 and liner 26 (line speed). The peripheral speed of the second fluted roll 14 detected by the speed detector TG l connected to the main motor M is designed to be input to a speed ratio station 40. Meanwhile, the power of the main motor M is designed to be transmitted via a powder clutch PC to the second press roll 36. Further, the peripheral speed of the second press roll 36 detected by the speed detector TG2 connected to the second press roll 36 is designed to be 13 input to the speed ratio station 40, where it is compared with the peripheral speed of the second fluted roll 14 to achieve accelerative or decelerative control of the second press roll 36.

Since the peripheral speed of the second press roll 36 locating on thedownstream side with respect to the direction of feeding the corrugating medium 16 is constantly controlled to be equal to that of the second fluted roll 14 again in this second embodiment, it does not happen that the bonding portions of the corrugating medium 16 and the liner 26 are rubbed or that they are pulled upstream or downstream to be separated from each other, ensuring glue-bonding of the corrugating medium 16 and the liner 26. Moreover, not only vibration and noises to be generated during formation of a single-faced corrugated board but also press marks to be formed on the liner of the single-faced corrugated board can be reduced like in the first embodiment.

(Modification) In any of the foregoing embodiments described above, the second press roll 36 is connected to the main motor M for driving the second fluted roll 14 via a powder clutch PC, and the second press roll 36 and the second fluted roll 14 are rotated at the same peripheral speed by electrically controlling the powder dutch PC. However, the present invention is not limited to such constitution. For example, as shown in Fig. 5, there may be employed a constitution, in which a gear (drive means) 42 attached to the rotary shaft of the second fluted roll 14 is meshed with a gear 44 (drive means) attached to the rotary shaft of the second press roll 36, and the gear ratio of these two gears 42,44 may be set such that the peripheral speed of the second fluted roll 14 and that of the second press roll 36 may be the same. Another gear 46 may be attached to the rotary shaft of the first press roll 34 to be meshed with the gear 42 of the second fluted roll 14, so that it may rotate at the same peripheral speed as that of the second fluted roll 14. Thus, the first press roll 34 and the second press roll 34 can be rotated constantly at the peripheral speed equal to that of the second fluted roll. 14, ensuring bonding between the corrugating medium 16 and the liner 26.

14 Meanwhile, with respect to the first press roll 34, the gear 48 attached to the rotary shaft of the roll 34 may be meshed with the gear 44 of the second press roll 36 via an idling gear 50, as shown in Fig. 6. In this case again, the gear ratio of the gears 50,48 must be set such that the peripheral speed of the second fluted roll 14 may be equal to that of the first press roll 34. As shown in Figs. 5 and 6, in the constitution where the second fluted roll 14 and the second press roll 36 are rotated at the same peripheral speed by mechanically connecting these rolls 14 and 36, the means for detecting the peripheral speed of these rolls 14,36 or the means for variably controlling the speed of the second press roll 36 may be omitted. Instead of mechanically connecting the second fluted roll 14 with the second press roll 36, the main motor M and the second press roll 36 may be connected by other mechanical means such as gears. Further, in Figs. 5 and 6, while the arrangement of the first fluted roll 12 and the second fluted roll 14 is described referring to the second embodiment shown inFig. 3, these rolls 12,14 may be, of course, arranged like in the first embodiment.

(Another embodiment) Further, in a single facer employing a plurality of press rolls 34,36 are employed in place of the single press roll, as described above, in which a corrugating medium 16 fed along the circumference of the second fluted roll 14 and a liner 26 to be pasted therewith are designed to be pressed against the second fluted roll 14 by these press rolls 34,36, one of these press rolls 34,36, i.e. the feed-out press roll 36 locating at a downstream position with respect to the direction of feeding the corrugating medium 16 and liner 26 may be designed to be rotated at a high peripheral speed compared with that of the press roll 34 locating at an upstream position. If the downstream press roll 36 is thus allowed to rotate at a peripheral speed higher than that of the upstream press roll 34, tension can be applied to the portion of the liner 26 locating between these two rolls 34,36 to bring such tense liner 26 into press contact with the corrugating medium 16, enabling excellent bonding between these webs.

In this case, the downstream press roll 36 is subjected to variable speed driving by the main motor M via the powder clutch PC, as described above.

Further, the second press roll 36 locating at the downstream position has a speed detector TG2 for detecting peripheral speed of the roll 36, as described above. Accordingly, it is recommended to provide an extra speed detector (not shown) on the first press roll 34 locating at the upstream position so as to detect peripheral speed of the roll 34, where the output value from the speed detector TG2 is compared with the output value from the speed detector (not shown), and to control the action of the powder clutch PC such that the peripheral speed of the second press roll 36 may be constantly higher than that of the first press roll 34. The peripheral speed of the downstream press roll 36 which is rotated faster (overspeed) than the upstream press roll 34 is, of course, at such a level that an appropriate tension may be applied to the liner 26 running between these two rolls 34,36.

(Variation) While, in any of the foregoing embodiments and modification described above, the second press roll is rotationally driven by the main motor for driving the second fluted roll, this invention is not limited to such constitution. The second press roll may be driven by an independent drive motor, the speed of which can be variably controlled. Meanwhile, the peripheral speed of the second fluted roll may be detected directly by a speed detector. Further, while the corrugating medium and the liner are adapted to be pasted together with the aid of two press rolls in any of the embodiments described above, it is also possible to dispose three or more press rolls adjacent to the circumference of the second fluted roll and to control the press roll locating at the downstream end to rotate constantly at the same peripheral speed as that of the second fluted roll. Incidentally, as the means for retaining the corrugating medium on the circumference of the second fluted roll, it is also possible to employ a constitution in which the corrugating medium is sucked onto the circumference of the second fluted roll Via through holes defined in the circumferential grooves of the roll by allowing the second fluted roll to assume a negative internal pressure.

16

Claims

What is Claimed is: 1. A single facer, containing a first fluted roll (12) having wavy flutes formed on the circumference; a second fluted roll (14), also having wavy flutes formed on the circumference to be engageable with the flutes of said first fluted roll (12), for imparting a required corrugation to a corrugating medium (16) to be passed between said two rolls (12,14); a gluing mechanism (22) for gluing crests of the thus corrugated corrugating medium (16); and- a plurality of press rolls (34,36), located on the circumference of said second fluted roll (14) and adjacent to the route of feeding a liner (26) to be pasted with said corrugating medium (16), for bringing said liner (26) into press contact with said corrugating medium (16) fed along the circumference of said second fluted roll (14) to paste them together; said single facer comprising: a drive means (PQ42,44Y for rotating at least one roll (36) of said press rolls (34,36), locating on the downstream end with respect to the direction of feeding said corrugating medium (16) and liner (26), constantly at the same peripheral speed as that of the second fluted roll (14).

1

2. A single facer, containing a first fluted roll (12) having wavy flutes formed on the circumference; a second fluted roll (14), also having wavy flutes formed on the circumference to be engageable with the flutes of said first fluted roll (12), for imparting a required corrugation to a corrugating medium (16) to be passed between said two rolls (12,14); a gluing mechanism (22) for gluing crests of the thus corrugated corrugating medium (16); and at least two press rolls (34,36), located on the circumference of said second fluted roll (14) and adjacent to the route of feeding a liner (26) to be pasted with said corrugating medium (16), for bringing said liner (26) into press contact with said corrugating medium (16) fed along the circumference of said second fluted roll (14) to paste them together; said single facer comprising: a drive means (PC) for variably controlling the peripheral speed of said feed-out press roll (36) locating on the downstream side with respect to the direction of feeding said corrugating medium (16) and liner (26); a detection means (TG2) for detecting the peripheral speed of said feed-out press roll (36); 17 a detection means (M1) for detecting the peripheral speed of said second fluted roll (14); and a control means (40) for controlling said drive means (PC) such that said feed-out press roll (36) may be rotated constantly at the same peripheral speed as that of said second fluted roll (14) based on the values detected by said detection means (TG1,TG2)

3. The single facer according to Claim 1, wherein said press roll (34), locating on the upstream side relative to said feed-out press roll (36) with respect to the direction of feeding said corrugating medium (16) and liner (26) is designed to be rotated at the same peripheral speed as that of said second fluted roll (14) to be brought into press contact with said roll (34) via said corrugating medium (16) and liner (26).

4. A single facer, containing a first fluted roll (12) having wavy flutes formed on the circumference; a second fluted roll (14), also having wavy flutes formed on the circumference to be engageable with the flutes of said first fluted roll (12), for imparting a required corrugation to a corrugating medium (16) to be passed between said two rolls (12,14); a gluing mechanism (22) for gluing crests of the thus corrugated corrugating medium (16); and a plurality of press rolls (34,36), located on the circumference of said second fluted roll (14) and adjacent to the route of feeding a liner (26) to be pasted with said corrugating medium (16), for bringing said liner (26) into press contact with said corrugating medium (16) fed along the circumference of said second fluted roll (14) to paste them together; wherein the feed-out press roll (36) of said press rolls (35,36), locating on the downstream side with respect to the direction of feeding said corrugating medium (16) and liner (26), is designed to be rotated at a peripheral speed greater than that of said press roll (34) locating on the upstream side with respect to the direction of feeding said corrugating medium (16) and liner (26).

5. A single facer substantially as hereinbefore described with reference to the accompanying drawngs.