PAPER FEEDING DEVICE FOR A BANDING MACHINE FOR LOGS OF SHEET MATERIAL

Abstract

Banding machine for packaging logs (2) consisting of stacks of folded, overlapped or interfolded sheets, adapted to apply a banding web of paper or plastic film (8) for banding it on four longitudinal sides, through means for packaging (23). A glue gun (12), during the motion of the web in a direction orthogonal to the drawings, spreads a glue line (4) for all the length of the web (8), near the lower free wing (29). The packaging web (8) crosses the walls (13) at two gaps (26, 27), respectively upper and lower. This way, pushing the compressed log (2) in the channel (6), the packaging web (8) is arranged stretched in front of the log (2). Thus, by the pusher (7), the log (2) is pushed against the packaging web (8) well beyond the gap (26, 27), causing a kind of self-packaging, i.e. the log is wound for ¾ by the web (8) and leaving two free wings, (29, 30), of which the second has glue on it. For avoiding, during the packaging, to dirty with glue passing through the gap (27), at least one among the first or the second section comprises a movable portion for enlarging said gap to allow the movement of said glued zone of said web. The particular said movable section can be a rotating wall portion.

Description

DESCRIPTION OF A PREFERRED EXEMPLARY EMBODIMENT

With reference to FIG. 1, a banding machine for packaging a log 2 consisting of stacks of folded, overlapped or interfolded sheets, is adapted to apply a banding web of paper or plastic film 8 for banding it on four longitudinal sides, through means for packaging 23 indicated generically as a zone in a thin line circle and shown hereinafter.

As shown in FIG. 1, the log 2 arrives in front of a pusher 7 operated by an actuator 1, in an already compressed shape, i.e. as a compact stack of longitudinal sheets. The way with which the log 2 comes in front of a pusher 7 is not described in detail. For example it can be used a system of known type, as described in U.S. Pat. No. 6,865,861, or in a way described in a european patent application in the name of the same owner of the present application and filed on the same day.

The packaging web 8 is unwound from a roll not shown in a direction perpendicular to the sheet of the drawings. For unwinding the web 8 an unwinding system provides upper and lower belts 5 coupled in pairs that operate in the plane of the web 8 and unwind it from a roll not shown. The length of the machine, not shown in a direction parallel to the log, i.e. in the direction orthogonal to the drawings, can be also of two-three metres or more, and can be exploited for treating a single log 2 at a time or more shorter logs and aligned to each other. More precisely, a glue gun 12, during the motion of the web in a direction orthogonal to the drawings, spreads a glue line 4 for all the length of the web 8, near the lower free wing 29.

The banding by the packaging web 8 is carried out in a known way by moving an actuator 1 that operates pusher 7, which pushes log 2 in a direction 25 into a channel 6 defined by walls 13. The packaging web 8 crosses the walls 13 at two gaps 26 and 27, respectively upper and lower gaps. This way, pushing the log 2 compressed in the channel 6, the packaging web 8 is arranged stretched in front of the log 2 as an obstacle along all the length of the machine. Thus, by pusher 7, the log 2 is pushed against the packaging web 8 well beyond the gap 26 and 27, causing a kind of self-packaging, i.e. the log is wound for ¾ by the web 8 leaving two free wings, 29 and 30, of which the second having a line of glue.

Then, after the withdrawal of pusher 7, the means for packaging 23, in a way shown hereinafter, with a system of transversal plates, lay wings 29 and 30, so that they are closed on the free side of the log 2. Finally, as compressed logs 2 are banded, they are pushed in channel 6 up to an outlet where they are drawn by a conveyor belt.

In detail, the features are now described of the means for packaging 23 of the machine according to the invention and the various operative steps.

With reference to FIG. 2, the means for packaging 23 comprises channel 6 defined by the two upper and lower walls 13 that consist of two upper plates, of which a front upper plate 3 and a rear upper plate 9, as well as two lower plates, of which a front lower plate 11 and a rear lower plate 10. The front plates and the rear plates, respectively upper and lower are separated by gaps 26 and 27, which in the following figures are indicated enlarged to enhance the understanding of the present description.

The compressed log 2, as above described already, is located at first in front of pusher 7, compressed between a portion of the front upper plate 3 and a platform located underneath, for example a mobile platform. Pusher 7 is ready to start moving in the direction of arrow 25. Pusher 7 is capable of pushing the log 2 as shown against packaging web 8, stretched along all the width of the banding machine, causing a self-packaging of the log 2.

At the end of the stroke of pusher 7, as shown in FIG. 3, the log 2 is wound by said packaging web 8 for ¾ of its longitudinal sides, except from the part that contacts pusher 7. As shown, always according to FIG. 3, the log 2 moves in the channel 6 against packaging web 8, leaving free only the two wings 29 and 30, which are then closed on each other for completing the packaging.

Free wings 29 and 30, are not yet passed through gaps 26 and 27, which are of minimum size, such that only the motion of the packaging web 8 is allowed, to avoid undesired movement during its introduction. In particular, the lines of glue 4 must pass through the gap 27, with the problem of dirtying the front lower plate 11 with glue. This would cause both a bad distribution of the glue on the free wing 29 with subsequent bad quality of the final packaging, and a risk of obstruction of said gap 27, as well as dirtying piston 8.

According to a preferred exemplary embodiment of the invention, means are provided that rotate the front lower plate 11 according to the direction of arrow 36. This system allows creating a larger gap 27 to allow the motion of the glue line 4 without the problem of dirtying parts of the machine.

Obviously, this rotation of the front lower plate 11 is only one of the possible solutions to the inventive concept, and still another desired movement for making a larger gap can be used, such as a lateral translation. Furthermore, the same system can be mounted on the upper plate of said front section with respect to the rear section, and then positioning the glue gun in the upper part of the machine.

As shown in FIG. 4, then, front plate 11, immediately after the motion of the glue line 4, moves back to the starting position by means for a counter-rotation indicated by means of arrow 21 for then allowing pusher 7 to withdraw to the starting position.

Before that pusher 7 carries out this movement it is necessary to avoid that, during said back movement, pusher 7 finds immediately behind itself the glue line 4 spread on free wing 29. In fact, during said back movement pusher 7 would cause a scattering of glue 4 with subsequent problems of bad quality of the final package and further problems of quality owing to the glue that would dirty the pusher.

A possible solution can be to raise the pusher, or to avoid that it moves along lower plate 10.

In a preferred exemplary embodiment, as shown in FIG. 5, a device is provided for lowering/lifting 17 a portion 31 of the rear lower plate 10 arranged on its contact surface with the free wing 29 of vacuum suction holes 18. In this way, owing to suction of air through holes 18, in the lowering movement of the portion of surface 31 by the actuator 17, the free wing 29 is dragged towards below integrally to the glue line 4, as indicated by the arrow 33. This creates the space necessary for moving pusher 7 in its motion of back stroke without touching the glue 4.

After the withdrawal of pusher 7 the closing of the wings 29 and 30 is carried out as shown in FIGS. 6, 7, 8 and 9.

More precisely, as shown in FIG. 6, an upper sheet laying member 16 is provided arranged aligned with respect to the edge front of log 2. The sheet laying member 16 is ready to be lowered according to the direction of the arrow 32 through a slit 38 made of the upper plate rear 9. In this way it is possible to stop the first free wing 30 of paper on the free side of the log 2 in the banding machine. Then, the sheet laying member 16 has a quick back stroke to the starting position (FIG. 7).

In the meantime, as shown in FIG. 8, the closing of wing 29 is carried out, on which glue line 4 is present, on the wing 30 without glue that is already aligned with the log 2. The piston 17, in fact, during its lifting motion towards the above engages with said free wing of paper 29 and causes the latter to close on that located underneath 30 without glue.

A following step of the wing closing phase is shown in FIG. 9, where a lever device 15 is provided that rotates in the direction of log 2 according to arrow 19 causing a further pressure on the paper. This further pressure ensures a better grip of the wing 29 with glue on that 30 without glue and then a better closing.

With a rotation not shown opposite to arrow 19, finally a motion of piston 17 follows back to the starting position in order to receive the next log 2, again as shown in FIG. 2. In fact, as shown in FIGS. 6-9 contemporaneously to closing wings 29 and 30 a log 2 (FIG. 7) is arrived in front of pusher 7 which begins to push (FIGS. 8 and 9) it in channel 6.

In an exemplary embodiment of the invention, shown in figures from 10 to 16, at least one part of the second section is movable. In particular, plate 101 can rotate as indicated by arrow 114 about an axis orthogonal to the conveying direction of log 102 (FIG. 12) increasing therefore the gap 127 through which web 108 can move.

Like the previous case, the introduction of log 102 in channel 106 is effected by pusher 112. It pushes log 102 against a web 108 fed by belts 105 towards means for packaging 123. The web 108 is thus dragged by log 102 in channel 106 up to freeing it from belts 105.

To avoid that the free portions of the web 108 can follow undesired paths and can affect the correct packaging of log 102, in this case vertical guides 140 are provided arranged between the belts 105 and the plates 113. In particular, the guides 140 are associated to a vacuum system in order to cause the suction of the web 108 through holes 141 and to keep it adhesive to their surface. This technical solution achieves a rate of precision still higher than the case described with reference to figures from 1 to 9.

Once log 102 reaches the second section, the plate 101 rotates as indicated by arrow 114 allowing the motion of the web 108 having a glue line 104. In particular, the plate 101 has suction holes 111 in order to keep always adhesive the free wing 129 to its surface, as it occurs for vertical guides 140. This way it is possible to allow the withdrawal of pusher 112 without that this is dirtied of glue, as shown in FIG. 14.

In a way similar to the solution previously described, the lowering of the sheet laying member 116 blocks the free wing 130 on log 102. Then, a rotation of the plate 101 opposite to the previous one blocks the free wing 129 having the glue line 104 on log 102 completing the packaging.

Obviously, this alternative solution is only one of the possible solutions to the inventive concept. In fact exactly a specular solution can be used and i.e. causing the rotatiom of the upper plate of the withdrawn section, positioning in the upper part the glue gun. Furthermore, it is possible to couple to this alternative solution the piston 17 of the preferred configuration and described in FIG. 8. This way a back stroke rotation of plate 101 would be avoided causing the closure of the wing by said piston in a way already described. Furthermore, the plate 101, having in this case only the function of increasing the passage gap, can be of a much more limited length leaving to said piston all the functions already described of closing the wing with glue on the log.

The foregoing description of a specific embodiment will so fully reveal the invention according to the conceptual point of view, so that others, by applying current knowledge, will be able to modify and/or adapt for various applications such an embodiment without further research and without parting from the invention, and it is therefore to be understood that such adaptations and modifications will have to be considered as equivalent to the specific embodiment. The means and the materials to realise the different functions described herein could have a different nature without, for this reason, departing from the field of the invention. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation.

Claims

1. Banding machine for banding a log of sheet material with a packaging sheet comprising: a packaging channel, consisting of a first and a second consecutive sections, between said first and second sections a narrow gap being present;pushing means adapted to convey a compressed log in said channel, said log under the action of said pushing means entering said first section and then running in said second section up to a predetermined depth;means for arranging a packaging web for said log between said first and said second section running through said gap, whereby said web wraps on three sides said log that moves in said channel moving from said first to said second section, on said web a line of glue in a predetermined zone being previously spread;

2. Banding machine according to claim 1, wherein said channel comprises at least two lower plates adjacent and distanced by said gap, said lower plates being located one in a front position and one in a rear position with respect to each other in a way suitable to form a support/sliding plane for said log, andat least two upper plates adjacent and distanced by said gap, located one in a front position and one in a rear position with respect to each other and in a way suitable to form a upper plane for containing said log,wherein said first section comprises said front plates and said second section comprises said rear plates,at least one of said plates of said sections being movable for enlarging said gap.

3. Banding machine according to claim 2, wherein for enlarging said gap said front lower plate is movable.

4. Banding machine according to claim 2, wherein for enlarging said gap said rear lower plate is movable.

5. Banding machine according to claim 3, wherein said front plate belonging to said couple of lower plates has a rotatable motion in order to increase the size of the gap of passage for web of paper with glue spread along a line thereof in its lower part.

6. Banding machine according to claim 3, wherein said front rear plate, belonging to said couple of lower plates has a rotatable motion in order to increase the size of the gap of passage for web of paper with glue spread along a line in its lower part.

7. Banding machine according to claim 1, wherein said means for arranging a packaging web have at least two couples of pulling belts, of which one couple located in a position higher than said upper plates and a couple located in a position lower than said lower plates and such that allowing the sheet located in said gap to be laid along all the width of the machine to allow then banding of the log.

8. Banding machine according to claim 1, wherein between said couples of belts and said channel vertical guides are provided adapted to bring said web towards said means for packaging, said guide having suction holes, connected to a vacuum system, adapted to keep said web adhesive to the surface of said guide.

9. Banding machine according to claim 1, wherein said means adapted to packaging the log comprises at least one system of glue distribution adapted to spread an amount of glue along a line of the web of paper and located in a position set between said plates and said belts, said means for distribution of the glue along a line of the web of paper comprising a fixed glue gun located distanced between said couple of lower pulling belts of said web and said plates.

10. Banding machine according to claim 1, wherein means are provided for closing the free wings of web wound about the log, said means for closing comprising an upper sheet laying member having vertical movement located aligned with said log, adapted to stretch a first free wing of said web on said log.

11. Banding machine according to claim 1, wherein means are provided for closing the two wings comprising a movable portion of said lower plate located aligned with said log adapted to block said free wing with glue on said free wing without glue.

12. Banding machine according to claim 8, wherein said lower plate has vacuum suction holes connected to a suction system, and wherein said portion of lower plate is associated to means for lowering below the level of the lower plates for allowing the back stroke of said pusher without that the latter is dirtied with glue spread on the web.