EP0117782B1 - Device for instantaneously adjusting the width of spread of adhesive during the manufacture of corrugated board, and method of using the same - Google Patents

Abstract

Device permitting the instantaneous changing of the width of application of glue to a web of paper in the manufacture of corrugated cardboard, the glue being applied to the web with the aid of a gluing cylinder (5) driven rotationally and dipping into a tank of glue over a width adjusted by two barriers which are movable in the tank. It includes a detachable auxiliary doctor device (1) comprising two doctors (2) to be applied momentarily to the two longitudinal ends of the gluing cylinder (5), on the non-immersed top part of the latter, the said doctor device being in addition equipped with a device for adjusting the distance (L3) left free for the passage of the glue between the two doctors.

Description

The present invention relates to a device making it possible to carry out the instantaneous change of glued width during the manufacture of corrugated cardboard, in particular single-sided, more particularly during the passage of an automatic connection between two reels of fluted paper of widths. different. The invention also relates to a method of using this device.

In a corrugator intended for the manufacture of single-sided corrugated cardboard, for example as described in French patent 2,433,985, the strip of fluted paper is corrugated by the passage between two fluted rolls and glued to a strip of cover paper between the lower grooved cylinder, placed downstream, and a smooth cylinder around which the cover paper passes. The aforementioned French patent describes a device of the type set out in the preamble of claim 1.

The glue is deposited on the top of the corrugations of the corrugated paper using a gluing roller driven in rotation and dipping in a glue tank - The width of the gluing area, i.e. the area of the cylinder wetted with glue is conventionally imposed, as described in detail in the aforementioned French patent 2,433,985, by the adjustable distance between two barriers, both of which are movable in the glue tank.

If the gluing area is less than the width of the strip of corrugated paper, waste is produced by lack of gluing at the edges.

If the gluing area is greater than the width of the corrugated paper strip, the excess glue is then deposited on the lower corrugated cylinder, causing it to become clogged, which means that machine stops for cleaning. These two problems have become crucial due to the widespread use of reel launchers making it possible from now on to connect practically end to end the end of one reel on the beginning of the other. When the two coils have the same width, the gluing area remains the same and there is no difficulty. But the vagaries of the manufacturing programs mean that often the width of the successive reels is not the same, and it is then necessary to modify the position of the barriers so that the gluing area corresponds to the new width of the paper being worked. This movement takes some time and as the change in width of the paper is instantaneous, there is either waste due to lack of bonding, or fouling of the lower grooved cylinder.

This problem is currently being solved by stopping the machine completely during the movement of the barriers in the glue tank, which obviously results in a significant loss of production.

The device described in document DE-C-282.393 relates to a doctor blade which is applied to a glue transfer roller between the paper and the roller which dips in the glue. There is no transverse partition in the glue tank.

In this prior device it is an adjustment system which has the disadvantage of requiring a significant adjustment time to pass from one gluing width to another, which is incompatible with the usual means of change. quick paper sizes.

The essential characteristic of the present invention lies in the fact that a system of movable transverse partitions in the glue tank is used together with a system of movable scrapers on the glue roller, one of the systems taking over from the other by completely erasing the idle times due to the settings. This is obtained in particular thanks to the device making it possible to instantly move the doctor blades between an active position and a release position.

The device of the invention makes it possible to instantly change, therefore without stopping the machine, the width of the gluing area of the gluing cylinder when the connection of the two coils passes. It is characterized in that it further comprises a removable auxiliary scraping device, comprising two scrapers intended to be applied simultaneously to the two ends of the gluing cylinder, on the non-submerged upstream part thereof, this scraping device being also equipped with means for adjusting the distance left free for the adhesive to pass between the two doctor blades, and with means for moving the doctor blades between an active position pressing on the gluing cylinder and a release position out of contact with the cylinder .

The device according to the invention is characterized in that it further comprises an auxiliary removable scraping device comprising two doctor blades intended to be applied momentarily to the two ends of the gluing cylinder, on the non-submerged upstream part thereof, this scraping device being moreover equipped with means for adjusting the distance (L) left free for the passage of the adhesive between the two scrapers, and means for moving the scrapers between an active position resting on the gluing cylinder and a release position out of contact with the gluing cylinder.

The present invention also relates to a method of using the above defined device applied in the case where one passes from a large width of paper to a smaller width, characterized by the following series of operations: scraping device being distant so as "not to be applied to the gluing cylinder, the distance between the two scrapers is adjusted so that it is equal to the new smaller width, it is determined when the connection of the two widths must arrive at the place where the paper is glued, and the scraper device is applied at the time to the gluing cylinder, - then the quench width adjustment device is moved between the gluing cylinder in the glue so as to adjust it to the new width, - the scraping device is then moved away again so that it is no longer applied to the gluing cylinder.

The invention will be better understood using the following description of a preferred embodiment, with reference to the accompanying drawings in which: - Figure 1 is a schematic representation of the auxiliary scraper device fitted to the device of the invention . - Figure 2 is a perspective view of one of the scraper sleeves fitted to the auxiliary device of Figure 2. - Figure 3 is a schematic side view of a single-sided corrugator equipped with the device of the invention in the low position scraping, - Figure 4 is an end view, in the direction F of Figure 2, of the part of the single-sided corrugator equipped with the device of the invention, the latter being in the raised position.

Referring first to all of Figures 1 and 2, the auxiliary scraper device consists of a metal roller 1 coated at its two ends with a non-metallic material, such as polyurethane, forming two sleeves 2 which are extra thickness.

As can be seen in the drawings, the two sleeves 2 have a symmetry with respect to the transverse median plane 3 of the cylinder 1, and their facing internal faces 4 form an angle a with the horizontal and are cut in a helix as shown in the perspective of figure 2.

If we apply, as shown in Figure 1, the cylinder 1 equipped with its sleeves 2 on a gluing cylinder 5, we see that the two sleeves 2 come into contact with the roller 5, so that the roller 1 does not touch not the roller 5, which frees a passage for the adhesive 6 between these rollers, the width L of which corresponds to the distance which exists between the two sleeves 2 along the contact generator of the two cylinders 1 and 5.

• - une position angulaire b₁ donne une distance L₁
• - une position angulaire b₂ donne une distance L₂
• - une position angulaire b₃ donne une distance L₃
• - une position angulaire b₄ donne une distance L₄

Furthermore, the width of the space 6 is made adjustable by the very shape of the sleeves as a function of the angular position b which is fixed for the roller 1 relative to its axis:

• - an angular position b ₁ gives a distance L ₁
• - an angular position b ₂ gives a distance L ₂
• - an angular position b ₃ gives a distance L ₃
• - an angular position b ₄ gives a distance L ₄

To obtain a distance L between the two sleeves 2 on a given generator corresponding to the contact generator between the rollers 1 and 5, the roller 1 is brought in, using an irreversible motor at low speed 7 for example. the corresponding angular position b.

An angular measurement device, such as a potentiometer 8 connected to an electrical measurement device, makes it possible to ensure that the roller 1 is indeed in the desired angular position b. The motor 7 being irreversible, the cylinder 1 is then immobilized in rotation despite the contact with the glue cylinder 5 which itself rotates continuously. The sleeves 2 form a doctor blade for the adhesive outside the space 6, and this falls back into the glue tank where the cylinder 5 soaks.

FIGS. 3 and 4 schematically represent a single-sided gluing machine using, to allow instant change of glued width, the scraper device of FIGS. 1 and 2.

We recognize in FIG. 3 a single-sided corrugator in which, in a very conventional manner, the corrugated paper 9 is corrugated by passing between an upper corrugated cylinder 10 and a lower corrugated cylinder 11, then glued to a cover paper 12 between the cylinder lower grooved 11 and a smooth cylinder 13.

The fluted paper, once formed, receives glue on the top of its corrugations by means of a gluing cylinder 5, the lower part of which dips in the glue 14 contained in the tray 15. The thickness of glue deposited on the fluting paper is regulated by the interval which exists between the gluing cylinder 5 and a non-submerged cylinder 16, called the doctor cylinder.

Also in a conventional manner, the width of the gluing zone of the gluing cylinder 5 is imposed by the distance existing between two barriers 17, a distance which is adjustable, as can be seen in FIG. 4, by a conventional drive translation device 18 and endless screw 19 with inverted steps. There is also a distinction in FIG. 4 of the conventional device for driving in rotation the gluing cylinder 5 with a motor 20 and angular gear 21.

Now in accordance with the invention, a scraper device as described above with reference to FIGS. 1 and 2 can be temporarily applied to the top, upstream side, of the gluing cylinder 5.

As seen in Figures 3 and 4, the roller 1, furnished with its two sleeves 2 described above, is supported by two levers 22, each lever being articulated on a pivot 23 fixed in each frame 24 and controlled by a jack 25 also articulated on the corresponding frame 24. The jacks 25 make it possible to obtain a high position in which the roller 1 is not in abutment on the gluing cylinder 5, which allows the free passage of the adhesive deposited on the cylinder after soaking in the tank 15.

In the low position, the roller 1 presses on the cylinder 5 via the sleeves 2, then limiting the gluing area to the distance L which separates, on the contact generator of the roller 1 and the gluing cylinder 5, the two scraper sleeves 2.

The roller 1 can be driven in rotation by means of the irreversible motor 7 and the pinion and chain transmission 26. It is thus possible to adjust the desired distance L between the two sleeves 2 before applying the roller 1 to the cylinder 5 The motor 7 being irreversible, the roller 1, once brought to its angular position b for adjustment, is locked in this angular position despite contact with the cylinder 5 which itself rotates continuously. The distance L is therefore kept for the entire contact time between the roller 1 and the cylinder 5. The excess adhesive due to the wiping of the cylinder 5 by the sleeves 2 is recovered in a transverse chute 27.

• - Premier cas: on passe d'une grande largeur de papier à une largeur plus petite.

The operation of the device which has just been described is as follows:

• - First case: we go from a large width of paper to a smaller width.

During the wide-width working period, the roll 1 was raised and the width of the gluing area of the roll 5 was adapted to the width of the corrugated paper strip only by the barriers 17 of the glue tank. To prepare the change of width, the roller 1 still being in the high position, by means of the motor 7, the distance L between the two sleeves 2 is adjusted to the new smaller value. A detection system 28, with a photocell for example, detects the connection of the two widths. An electronic computer, not shown, calculates the time that will elapse before the connection arrives at the location where the paper is glued, as a function of the distance to be covered and the speed of travel of the strip. At the end of this time, the jacks 25 are actuated to bring the roller 1 into contact with the cylinder 5, instantly limiting the gluing area to the new distance L corresponding to the new width worked. From this moment the barriers 17 are set in motion to come to be in accordance with the new width worked. Roller 1 can then be raised again. The excess adhesive due to the wiping of the cylinder 5 by the sleeves 2 during the movement of the barriers is recovered in the chute 27.

We see that during the entire time of operation of the barriers 17 between the wide position and the new narrower position it is the scraper sleeves which will have temporarily ensured the limitation of the gluing area, and this instantaneously.

• Dans ce cas, pour préparer le changement de largeur on applique à nouveau le rouleau 1 et les racles 2 sur le rouleau colleur 5, ce qui est sans effet immédiat car la largeur d'encollage déterminée par les barrières 17 est la même que celle déterminée par la position angulaire des racles hélicoïdaux 2. On peut ensuite, au moyen du moteur 18, déplacer progressivement les barrières 17 jusqu'à leur nouvelle position correspondant à la nouvelle grande largeur. Pendant tout le temps de manoeuvre des barrières 17 la colle excédentaire entrainée par le rouleau 5 sera enlevée par les racles 2, et récupérée par la goulotte 27. Au moment déterminé par le calculateur électronique où le raccordement des deux bandes de papier arrive en face du rouleau 5, les vérins 25 sont actionnés pour relever le rouleau 1 les racles 2 cessent alors leur action et la zone d'encollage est instantanément amenée à sa nouvelle largeur plus importante déterminée par les barrières 17.

- Second case: we go from a small width of paper to a larger width:

• In this case, in order to prepare the change in width, the roller 1 and the doctor blades 2 are again applied to the gluing roller 5, which has no immediate effect since the gluing width determined by the barriers 17 is the same as that determined by the angular position of the helical doctor blades 2. It is then possible, by means of the motor 18, to progressively move the barriers 17 to their new position corresponding to the new large width. During the whole time of operation of the barriers 17 the excess glue entrained by the roller 5 will be removed by the doctor blades 2, and recovered by the chute 27. At the time determined by the electronic computer where the connection of the two strips of paper arrives opposite the roller 5, the jacks 25 are actuated to raise the roller 1 the doctor blades 2 then cease their action and the gluing area is instantly brought to its new greater width determined by the barriers 17.

Of course, the invention is not strictly limited to the embodiment which has been described by way of example, but it also covers the embodiments which would differ from it only in details, in variant embodiments or by use of equivalent means. Thus one could for example use other equivalent means to adjust the variable spacing between the doctor blades 2 which would not necessarily be helical sleeves, as well as to move them selectively between an active position pressing on the ends of the gluing cylinder 5 and a release position out of contact with this cylinder 5.

Claims (2)

1. Device for instantaneously adjusting the width of spread of adhesive during the manufacture of corrugated cardboard, where an adhesive substance is applied onto the web of paper (9) by means of a rotating gluing cylinder (5) partially immersed into the adhesive substance (14) on a width defined by a device (17) adjusting this immersing width of the gluing cylinder into the adhesive substance, characterized by the fact that it also comprises an auxiliary removable scraping device provided with two scrapers (2) to be temporarily applied on both ends of the gluing cylinder on the upstream, not immersed part, this device being provided with means (7) adjusting the distance (L) left free for the passage of the adhesive substance between two scrapers (2), as well as means (25) for shifting the scrapers (2) between an active position where they press onto the gluing cylinder (5) and an offset position without contact with the gluing cylinder (5).

2. Method for using the device according to claim 1, applied when the width of the paper is to be reduced, characterized by the following operating steps:

- the distance (L) between two scrapers (2),is set so that this distance becomes equivalent to the new reduced width, while the scraping device (1) is set off from the gluing cylinder (5);

- the moment where both widths will meet at the gluing point is determined, and the scraping device is then applied against the gluing cylinder (5),

- the device (17) adjusting the immersion width of the gluing cylinder (5) into the adhesive substance is shifted, in order to obtain the new width,

- the scraping device is then set off, so that it doesn't touch the gluing cylinder any more.

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