EP0739710B1 - Pressplate for a machine for producing cardboard - Google Patents

Description

The present invention relates to a baler in a so-called single-sided corrugated cardboard manufacturing machine sheet of fluting paper whose crests are glued on a first cover sheet. This intermediate box is also called single-sided. In a later double-sided machine, this first carton is either directly assembled to a second sheet of cover paper outside to give a cardboard called double-sided, either before assembled with a second single-sided carton to obtain a final carton called double-double.

In the single-sided machine, the groove paper is preheated and humidified before passing between two fluted cylinders which are heated with steam. The groove thus formed is maintained against the lower grooved cylinder by means of combs, or a system of the external environment, or a vacuum system of the interior of the lower grooved cylinder, the surface of which has slots of communication. A glue roller bathed in a glue tank deposits a predetermined amount of glue on the ridges of the grooves. The paper also preheated cover and the groove paper are finally pressure assembled between the lower grooved cylinder and a device support called a smoothing press. The most commonly used baler is consisting of a smooth cylinder parallel to the lower grooved cylinder against which it is in support. These two cylinders rotate at the same speed device so that the cover and groove papers are driven identically during assembly. The cylinder smooth is also pressed against the grooved cylinder with a very strong important so that the pressure at the contact thread is sufficient to burst the glue cells and simultaneously firmly apply the cover paper against the groove paper. Finally, this smooth cylinder is heated to further accelerate the setting of the glue. However, the major drawback of this smooth cylinder is the brutal jolts and repetitive produced with each passage of a groove of the lower cylinder, and this in particular due to the necessarily large support force. No only these jerks damage the paper at the crest of the grooves of the cardboard, but they generate a strong surrounding noise. In addition, to some speeds, resonance phenomena can occur during from which the cylinders can oscillate transversely to their axis of rotation causing the sheets of paper to no longer be correctly applied and glued. These jolts also cause wear premature grooves of the lower cylinder.

To overcome these problems, we have proposed heald presses, the contact surface is greater than that between two grooves. According to a first solution mentioned in document US 4,481,066 and described in more detail in document FR 2 142 591, the baler is consisting of a cross member held at its ends by branches lower levers, and the active side of which faces the grooved cylinder lower is arched in portion of cylinder of equal radius, even slightly higher than that of the grooved cylinder. By acting on the branches upper end levers by means of a pair of cylinders, bring this arched face into contact with the grooved cylinder with a predetermined pressure. The edges of the active face can be folded towards outside or be completed with deflection rollers to better drive the cover sheet. This cross member can also be hollow for the heating steam passage. However, less balanced and less rigid that a cylinder, such a cross member can twist and warp so that the application pressure is no longer uniform over the entire length of the cylinder grooved. The quality of the gluing is then greatly altered. According to one second solution mentioned in document FR 2 142 591 and better described in document DE 25 27 819, the baler consists of a endless belt passing between upper and lower rollers located parallel and close to the lower grooved cylinder, respectively at mid-height and below. This strip is thus in contact with the cylinder grooved on a quarter of the lower periphery. This endless band can be a thin strip of steel or a carpet of copper, cotton or fiber threads synthetic. However, the pressure applied to the sheets by this heald press depends on the tension applied to the endless belt. It suits then to provide a complex mechanical spacing device for one of the rolls of the endless belt relative to each other, and this with possibility adjusting this large voltage to a specific value. Again, he it is impossible to guarantee the maintenance of a constant tension throughout the width of the endless belt, therefore a uniform application pressure of the cover sheet against the flute sheet.

The object of the present invention is a heald press in a more efficient single-sided corrugated machine that is to say that constantly applies pressure over time uniform across the width of a cover sheet joined to a groove sheet passing around the lower grooved cylinder. In addition, the baler must allow adjustment to a precise pressure value of application in order to obtain an effective setting of the adhesive without thereby damage the leaves. Finally, the design of this baler must be relatively simple to ensure operational reliability in the time and ease of implementation and maintenance at cost reasonable.

• une série de dispositifs identiques d'appui disposés côte-à-côte le long du cylindre cannelé,
• chaque dispositif comprenant un patin dont la surface d'appui contre le cylindre cannelé est arquée selon un rayon sensiblement égal à celui du cylindre cannelé pour couvrir une pluralité de cannelures, chaque patin étant mobile entre deux positions, engagée et désengagée, sous l'action d'un actuateur associé dont la force d'action est réglable séparément.

These goals are achieved with a healer which includes:

• a series of identical support devices arranged side by side along the grooved cylinder,
• each device comprising a shoe whose bearing surface against the grooved cylinder is arcuate by a radius substantially equal to that of the grooved cylinder to cover a plurality of grooves, each shoe being movable between two positions, engaged and disengaged, under the action an associated actuator whose action force is adjustable separately.

Thus, the fact that each device includes its pad with a arched surface covering a plurality of grooves and its actuator pressure application, each of these support devices can effectively trigger the glue and correctly assemble the papers exerting lower pressure in its assigned area longer but very precise, therefore less damaging to the grooved cylinder and cardboard. The use of a transverse series of separately adjustable devices ensures reliable application of common pressure uniform across the width of the carton. Each device, comprising a lighter force application structure than in the case of a cylinder or of a single sleeper, can make faster and better corrections controlled to achieve pressure application exactly predetermined. In particular, such a series of small support devices reacts more quickly exactly to possible transverse variations or longitudinal thickness of one or both sheets.

Advantageously, the bearing surface of the pads is covered or is made of a smooth and wear-resistant material such as a strip of polished metal: copper or stainless steel, or such as a synthetic material by example that marketed under the name Teflon.

According to a first embodiment, the support device comprises a plate carrying a shoe, this plate being pivotally mounted according to its edge lower or higher than the frame of the machine, the other edge opposite being connected by a first hinge to a linear actuator, such that a cylinder, itself connected to the frame of the machine by a second hinge, this actuator pushing the plate and the shoe against the cylinder grooved or removing it. If the skate is mounted on the plate close to its pivot, then this plate acts as a lever amplifying the force exerted by the actuator which can then safely be undersized for considerations saving.

Advantageously then, the shoe is a block of elastomer whose arched support surface is covered with a smooth and resistant material wear. Usefully, the periphery of the pad and its bearing surface can be square or rectangular oriented in the direction of movement of the papers, these forms being easily achievable. If we want to avoid any risk of maculature on the assembled cardboard, we can consider a diamond shape, the pads being nested thanks to an arrangement along two lines superimposed; or an alternately oval and thinned shape along the series.

According to a second embodiment, the support device includes a pad in the form of a band held at one of its ends by a cross member parallel to the cylinder and fixed to the frame of the machine, and in its other end by a movable cross member secured to a first end of a lever pivoting in the middle and whose opposite opposite end is connected by a first hinge to a linear actuator, such as a jack, itself connected to the frame of the machine by a second hinge, this actuator lifting or lowering the first end of the lever, which stiffens or loosens the band.

Advantageously, the strip can be metallic in copper or in polished stainless steel, or woven from metallic fibers, natural or synthetic, such as a mixture of carbon fibers and Teflon. This strip may have a slight longitudinal elasticity. The structure of this device is particularly simple therefore reliable.

According to a third embodiment, the support device includes a pad with prominent lower and upper edges on which are fixed the two ends of a curved strip, this shoe being mounted in pivoting according to its upper or lower edge on a first half of a arm, the other edge resting on this same half of the arm through a elastic means, such as a spring or an elastomer block, the end of the other half of the arm being pivotally attached to the frame of the machine, the first half of the arm being connected by a first hinge to a underlying linear actuator, such as a jack, itself connected to the frame of the machine by a second hinge, this actuator pushing this first half arm, therefore the shoe, against the grooved cylinder or removing it. Of preferably the braking force of the cardboard induced by the friction forces generated at the level of the heddle press according to the invention is compensated for by the fact that the cardboard is pulled downstream of the grooved cylinder and the heald press by a tractor device, in particular by a grille composed of a cylinder tractor around which the cardboard is wrapped by contact with its paper cover on at least a third of the circumference, and a support roll radially flexible in contact with the fluting paper. Usefully, the cover paper is brought to the heald press by an upstream cylinder preheating and guiding defining, with the downstream tractor cylinder, a cover paper feed angle, i.e. the angle at top of the portion of grooved cylinder with which this paper cover is in contact, greater than 30 °. So the tension in the cover paper creates additional application pressure.

Advantageously, the bearing surface of the pads is arcuate according to an angle at the top corresponding to the paper feed angle blanket. The width of the bearing surface is preferably between 100 and 200 mm. When the support surface of the pads is arched in a angle at the top less than the lashing angle, we can arrange the smoothing device according to the invention in the downstream part of the contact surface for have a flexible first roller at the start upstream of this surface application of cover paper. Alternatively, the guide cylinder and the flexible roller are replaced by a single smooth cylinder, identical to that used according to the state of the art, but brought near the grooved cylinder with just enough play to ensure the first application of the cover against the groove paper, but with pressure practically negligible.

• la figure 1 est une vue en perspective d'une d'une machine simple-face incluant une presse-lisse selon un premier mode de réalisation de l'invention,
• la figure 2 est une vue de côté d'un second mode de réalisation d'une presse-lisse,
• la figure 3 est une vue de côté d'un troisième mode de réalisation d'une presse-lisse,
• la figure 4 est une vue de côté d'une presse-lisse selon la figure 3 installée dans une machine modifiée, et
• les figures 5 illustrent des agencements de patins pour la presse-lisse selon la figure 1.

The invention will be better understood from the study of embodiments taken without any limitation being implied and illustrated in the appended figures in which:

• FIG. 1 is a perspective view of a single-sided machine including a heald press according to a first embodiment of the invention,
• FIG. 2 is a side view of a second embodiment of a heald press,
• FIG. 3 is a side view of a third embodiment of a heald press,
• FIG. 4 is a side view of a heald press according to FIG. 3 installed in a modified machine, and
• FIGS. 5 illustrate arrangements of pads for the heald press according to FIG. 1.

In Figure 1 is schematically illustrated in perspective a so-called single-sided manufacturing machine intended for the manufacture of a carton 6 also called single-sided consisting of the assembly of a paper groove 2 and a cover paper 4. More specifically, the groove 2 arrives from above and travels a first U-turn around a upper grooved cylinder 10. This paper 2 is grooved at the engagement of the upper cylinder 10 with a second grooved cylinder lower 12. The flute paper 2 'thus formed is held against this lower cylinder 12 during a second downward U-turn by a device not illustrated can be combs, an external overpressure created in a coating box or an internal depression in the grooved cylinder lower with radial openings allowing the suction of paper. During this second half-turn, a glue roller 13 illustrated in FIGS. 2 at 4 places a line of glue on each groove crest. In addition, a cover paper 4 is preheated during its rotation around a cylinder 14 then guided towards the lower part of the lower grooved cylinder 12 of so as to arrive well parallel to the 2 'flute paper against which it (4 ') is finally tackled. At this level, a heald press formed, according to the invention, a lateral series of support groups 30 applies pressure predetermined necessary and sufficient on the one hand to burst the glue cells and on the other hand firmly hold the two papers one against the other while taking the glue threads attaching the papers one to the other. More particularly according to the invention, the outgoing carton 6 is drawn in downstream by a grille made up of a traction cylinder 16 surmounted by a flexible backing roller 18. The cardboard 6 is thus wound up with its 4 more solid cover around the upper half of the traction cylinder 16. The contact pressure between this carton and this traction cylinder is reinforced by the support of the roller 18 acting against the fluting paper more fragile. This support roller includes a connected elastomer periphery in its central shaft by a series of longitudinal radial fins also made of elastomer, the cross section of which is oblique or even curved. According to a first embodiment illustrated in this figure 1, the baler is composed of a series of support groups 30 arranged side by side along the lower downstream part of the grooved cylinder 12. Each support group 30 first comprises a plate 36 whose lower edge is rotatably mounted by a pivot 38 on the same first cross member secured to the frame of the machine. The upper edges of the plates 36 are each connected to a second common cross member secured to the machine frame by means of a associated individual cylinder 40. Each cylinder is connected to the lower crossmember by a hinge 44 and at the upper edge of its associated tray by a second hinge 42. Thus, the output of the cylinder rod makes it possible to bring the the plate 36 towards the lower grooved cylinder 12 by rotation around from its lower pivot 38; while the removal of the cylinder rod moves the plate 36 accompanied by a slight lowering of the jack 40 by rotation around its lower hinge 44.

As clearly visible in this figure 1, the lower part of each plate 36 carries a shoe 32 whose base fixed against the plate has a rectangular shape whose length is parallel to the direction of travel of cardboard 6. On the other hand, the face 34 located opposite the grooved cylinder 12 is curved into a portion of a cylinder of substantially equal radius, or even slightly higher than that of this cylinder 12. The active bearing surface 34 pressing the cover paper 4 'against the groove paper 2' is preferably a surface with a low coefficient of friction and also a high resistance to wear. For example, this surface can be metallic, polished or a layer of synthetic material such as Teflon. Yes the skate body can be metallic, we prefer an elastomer block with relative elasticity to absorb any vibration residual due to speed or accidental thickness variations of either of the papers. As illustrated in Figure 5, the active surfaces 34 rectangular side-by-side together define a support area in which the pressure can be strong enough to trigger the glue but moderate enough not to damage the cardboard or the fluting of the lower cylinder 12. If you fear the formation of possible streaks on the cardboard cover sheet due to possible differences momentary pressure from one support group to another, then we can consider skates whose shape includes oblique lateral sides making the transition from one skate to another spread over a certain width. For example, we can consider pads 35 in the form of diamonds and arranged along two nested lines, or pads 33 side by side with curved side edges: these pads alternately having a tapering oval and concave shape. We can also consider a S-shaped skate edge

In Figure 2 is illustrated from the side a second embodiment of support groups 50. This embodiment is based on a pad taking the shape of a curved rectangular band 58 oriented in the direction of scrolling papers. The lower end of the strip 58 is attached to a first fixed cross member 56 of width equal to that of the strip. Conversely, the upper end of the strip is fixed to a mobile cross member 54 because it is attached to the end of a first branch of a lever 52 pivoting around a axis located at the end of an upright 51. The opposite end of the second leg of the lever is connected to the machine frame by an articulated jack 40 on two hinges: a lower 44 fixed to the ground and an upper 42 fixed to the lever. The lever branch carrying the cross member may have a length between half and a quarter, preferably a third of the length total of the lever so as to obtain a force amplification effect applied by the jack 40 to the strip 58 to stiffen it against the cylinder grooved lower 12. To facilitate the entry and exit of papers in these support groups 50, crosspieces 54 and 56 have surfaces rounded upper ends making the ends of the strip 58 curved towards outside. As illustrated, the length of the strip 58 is substantially equal at the tear-off arc (e) of the contact surface of the cover paper 4 against cylinder 12, as defined by the respective positions of the cylinder preheating and guiding 14 and the traction cylinder 16 relative to the lower grooved cylinder 12.

In Figure 3 is illustrated a third embodiment of a support group 60 based on an arm 64 movable in rotation around a pivot of upper base 66. The lower half of this arm 64 carries a shoe 61 mounted pivoting around a hinge 65 close to its upper edge, then that its lower edge rests on the arm 64 through an elastic means 63 such as a row of springs or a rubber stop.

Furthermore, the upper and lower edges of the shoe 61 are formed by transverse prominences with rounded ends on which the rounded edges are fixed in correspondence with a strip 62 constituting the application surface of the cover paper 4 against the paper of groove 2. The arm 64 is also connected to a cross member of the frame of the machine by a jack 40 articulated on two hinges: a lower 44 and a superior 42. The hinge 42, therefore the point of action of the jack 40, is located substantially in the middle of the pad 61 to push it so balanced against the lower grooved cylinder 12.

The application strip 62 of this embodiment, as well as the strip 58 of the previous embodiment, are preferably metallic such as copper or polished steel. Alternatively, these bands can also be woven of metallic threads or fibers or Teflon reinforced with carbon or any other synthetic fiber with a low coefficient of friction and high resistance to wear. In the embodiment illustrated in FIG. 3, the length of the action of the strip 62 is only one fraction between two thirds and three quarters downstream of the angle for covering the cover paper 4 against the cylinder 12 as defined by the relative position of the upstream guide roller 15 and traction cylinder downstream 16 relative to this lower grooved cylinder 12. Indeed, the bursting glue cells is made at this level by a flexible roller 11, similar to roller 18, and located vertically under the cylinder grooved 12. The pressure applied by the support groups 60 is then established at a fair value sufficient to ensure the proper maintenance of the paper cover 4 against the groove paper 2 during the setting of the glue.

Finally, in this embodiment, the guide cylinder 15 is smaller than the guide cylinder 14 of the previous embodiment of the that preheating is provided by a heating table 17 located at upstream.

FIG. 4 illustrates a variant of the embodiment according to Figure 3 also using a series of supports 60 and in which the guide roller 15 and the heating table 17 are replaced by a smooth cylinder 72 according to the state of the art. However, this smooth cylinder is mounted on bearings 72 movable vertically according to a servo (subject to a co-patent application by the owner), this servo allowing to bring this cylinder 70 close to the cylinder lower grooved 12 at a distance (h) exactly predetermined and regulated. This clearance (h) is established in such a way that the smooth cylinder only sets in contact the preheated cover paper 4 and the flute paper 2 and apply a force just necessary to burst the glue cells, but in any case weak enough not to risk damaging the carton 6 or the splines. In addition, an output deflection roller 19 located downstream of the grille made up of the traction cylinders 16 and 18 increases the angle of loading of the cardboard around this tractor cylinder 16 so that to induce in this cardboard a significant tension T generating, at the level of the adhesive contact surface against the lower cylinder 12, a resulting from additional pressure P.

Many improvements can be made to this press and to this single-sided machine within the scope of the claims.

Claims (10)

1. Smooth press in a single face machine for manufacturing corrugated cardboard (6), said smooth press implementing the application of a cover paper (4) against a fluted paper (2) passing around a corrugating roll (12), characterized by the fact that it comprises a series of identical support devices (30, 50, 60) arranged side-by-side along the corrugating roll (12), each device comprising a pad (32, 58, 61) whose support surface (34, 58, 62) against the corrugating roll is arced according to a radius approximately equal to that of the corrugating roll in order to cover a plurality of flutes, each pad being mobile between two positions, engaged and disengaged, under the action of an associated actuator (40) whose active force is separately controllable.
2. Smooth press according to claim 1, characterized by the fact that the support device (30) comprises a plate (36) that carries a pad (32), this plate being mounted on a pivot arrangement (38) at is upper or lower edge to the frame of the machine, the other, opposite edge being connected by a first hinge (42) to a linear actuator (40) itself attached to the frame of the machine by a second hinge (44), said actuator (40) pushing the plate (36) and the pad (32) against the corrugating roll (12) or pulling it back.
3. Smooth press according to claim 2, characterized by the fact that the pad (32) is a block of elastomer whose arced support surface is covered with a smooth, wear-resistant material.
4. Smooth press according to claim 2, characterized by the fact that the periphery of the pad (32) and of its support surface (34) is square, and is rectangularly oriented in the travelling direction of the papers; or is rhomboidal, the pads being imbricated due to a construction along two superposed lines; or is formed in an alternatively oval and thinned fashion along the series.
5. Smooth press according to claim 1, characterized by the fact that the support device (50) comprises a pad in the form of a belt (58) held at one end by a crossbar (56) parallel to the cylinder and fixed to the frame of the machine, and at its other end by a mobile crossbar (54) attached fixedly to a first end of a lever (52) that pivots at its midpoint, and whose other, opposite end is attached, by means of a first hinge (42), to a linear actuator (40), which is itself attached to the frame of the machine by a second hinge (44), this actuator lifting or lowering the first end (54) of the lever (52), thus stiffening or relaxing the belt (58).
6. Smooth press according to claim 5, characterized by the fact that the belt is made of polished metal or is woven of metallic fibers, natural fibers or synthetic fibers.
7. Smooth press according to claim 1, characterized by the fact that the support device (60) comprises a pad (61) having protruding lower and upper edges, to which are affixed the two ends of a curved belt (62), this pad being mounted in a pivot arrangement (65) at its upper or lower edge on a first half of an arm (64), the other edge resting on this same half of the arm across an elastic means (63), the end of the other half of the arm being fixed in a pivot arrangement (66) to the frame of the machine, the first half of the arm being attached by a first hinge (42) to a subjacent linear actuator (40), which is itself attached to the frame of the machine by a second hinge (44), said actuator pushing said first half of the arm (64), and thus the pad (61/62) against the corrugating roll (12), or pulling it back.
8. Single face machine comprising a smooth press according to one of the preceding claims, characterized by the fact that the cardboard (6) is drawn downstream from the corrugating roll (12) by a calender composed of a traction cylinder (16), around which the cardboard is wound by contact with its cover paper (4) on at least a third of the circumference, and further composed of a radially flexible support roller (18) in contact with the fluted paper (2).
9. Single face machine according to claim 8, characterized by the fact that the cover paper (4) is led towards the smooth press (30, 50, 60) by an upstream preheating and guiding cylinder (14, 15) that defines, together with the downstream traction cylinder (16), a tension angle (e) greater than 30°.
10. Single face machine according to claim 9, characterized by the fact that the upstream preheating and guiding cylinder (70) is led close to the corrugating roll with an amount of play (h) just sufficient to ensure a first application of the cover paper (4) against the fluted paper (2), but with a pressure that is practically negligible.

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