Tunnel and support for a printing and/or coupling machine

Abstract

 A drying tunnel for printing and/or coupling machines comprises a lower structure (1) and a movable upper cover (2), said lower part (1) comprising a series of mechanisms and devices for moving webs (3) of paper and/or film and equipped with rollers (6) and characterised by the fact that said upper cover (2) can be vertically lifted and horizontally moved using special lifting mechanisms such as jacks (20,22) for example.
The machine also has a cradle support (104) to minimise revolving friction of the rollers (6).

Description

[0001] The subject of this invention is a tunnel, or cover, for printing and/or coupling machines, especially but not exclusively rotogravure machines, which, thanks to its conformation, is easier to use in terms of maintenance and cleaning, operations which create considerable inconvenience in the printing and coupling machine sector.

[0002] Printing and/or coupling machines requiring products such as ink, glue and the like need careful daily maintenance to keep all moving parts clean and free from build-up and residues of materials used for printing and/or coupling.

[0003] These machines have largely similar structures, being made up of a tunnel beneath a cover inside which several rollers run continuously to pull paper or polyethylene film which has already been printed or spread with glue. The drying of glued or printed paper or film also takes place in these tunnels. It therefore appears obvious that there are at least two problems to solve: the drying of the paper or film and the cleaning of the tunnel from residues of adhesive and ink.

[0004] Tunnels with the upper part hinged in a variety of ways to the lower, main part, have already been presented. In this case the upper part can only be inclined by a certain angle, meaning that, in correspondence with the hinged area, the space for introducing the cleaning equipment is particularly small and becomes completely non existent near the mechanism that hinges the upper part to the base of the tunnel.

[0005] This invention regards a drying tunnel for printing and/or coupling machines which eliminates the abovementioned problems by adopting a cover that is not hinged to the main base but can be lifted and moved away from the tunnel in a parallel position.

[0006] The achievement of this aim will become clearer further on in this document, as reference is made to the annexed figures, which are indicative and not binding, in which:

[0007] - figure 1 shows a cross-section of the tunnel in question in the closed position;

[0008] - figure 2 shows the view in figure 1, in a schematic longitudinal section;

[0009] - figure 3 shows a cross-section of the tunnel with the upper cover in the raised position;

[0010] - figure 4 shows the view in figure 3, in a schematic cross-section;

[0011] - figure 5 shows a schematic cross-section of the tunnel with the upper cover raised and moved sideways; and

[0012] - figure 6 shows the view in figure 5, in a schematic cross-section;

[0013] figures 7 and 8 show a schematic view of the tunnel in the raised and lowered position;

[0014] - figure 9 shows a schematic view of the tunnel in a horizontally moved position;

[0015] - figure 10 shows a schematic view of the tunnel in an inclined position;

[0016] - figure 11 shows an overhead view of a partial section of an example of a roller support;

[0017] - figure 12 shows the cross-section of the support shown in figure 10; and

[0018] - figure 13 shows the sectioned frontal view of the support shown in figure 11;

[0019] - figure 14 shows the cross-section of another version of the support.

[0020] In the annexed figures, number 1 is used to indicate a drying tunnel for printing and/or coupling machines. It is normally equipped with an upper structure 2 which acts as a cover, and of several different devices for moving and managing rolls 3 of paper and/or film, such as polyethylene. Said devices consist largely of motors 4 and chains 5 and running and guide rollers 6.

[0021] Said machine comprises, for instance, a first roll 3b, which holds a first film, and a second roll 3b, which holds a second film, and a roll 3c for winding the coupled films.

[0022] This invention also regards the upper cover 2 of the tunnel, which is housed on the lower part 1 and can be moved vertically and horizontally, allowing said upper cover 2 to be placed in a raised and shifted position compared with part 1 of the tunnel, leaving the latter totally uncovered.

[0023] This solution, which can be seen in figure 5, is obtained using special mechanisms and servo controls for lifting the cover 2, such as, roughly-speaking, jacks, screws, recirculating screws with worms or similar, as well as other mechanisms and horizontal movement devices of the cover 2, such as pulling chains and runners.

[0024] In this way it is possible to achieve a series of advantages such as, by way of example, the reduction of the distance between the lower part of the cover 2 and the chain 5 along which the paper and/or polyethylene film rolls, to a distance of between 5 and 40 millimetres, but preferably 5 millimetres, consenting faster drying by special insufflators or hot air vents 7; or the starting up of the so-called "drawing-in bar" which connects and pulls the initial portion of the roll of film, slightly lifting the upper cover 2 as it passes; or, lastly, thorough cleaning of all the moving parts inside the upper cover.

[0025] In a preferred version, said cover can be lifted from the tunnel by at least one, but preferably several, jacks. For example, said cover can be lifted by several front jacks 20, operatively connected to the cover in a frontal area 20a, and by several rear jacks 20, operatively connected to the cover in a rear area 20b.

[0026] In another version, said front and rear jacks can be activated independently, thus lifting the front area 20a and the rear area 20b to different heights.

[0027] In other words, said cover can be inclined, thus creating a cavity 30, usually in a funnel shape, between the inner surface of the cover and the rollers.

[0028] In another version, said jacks 20, 22 can be activated mechanically. In another version, said jacks can be activated in a controlled way, commanded from a central control panel which displays the status of the jacks and is used to set new statuses.

[0029] Under normal operating conditions, the printing and/or coupling machine is initially "drawn-in", in other words, the film or the tape to be coupled is introduced into the machine.

[0030] This operation should preferably be performed by lifting the cover 2 of the tunnel, both in the front area 20a and in the rear area 20b, in such a way so that the cavity 30 is roughly 40 millimetres high.

[0031] The film to be treated is wound around the first roll 3a. The head of the film, or the free edge, is connected to a drawing-in bar, operatively connected to the drawing-in chains 5, set to the sides of the rollers 6 and suitably moved.

[0032] The drawing-in bar moves on the rollers 6. unwinding the film from the first roll 3a. When the bar reaches the front area 20a of the machine, the film is cut in line with the drawing-in bar and wound, manually or by special winding devices, onto the second roll 3b.

[0033] The cover 2 is lowered until the cavity reaches a height of between 5 and 40 millimetres, preferably between 8 and 10 millimetres.

[0034] The ink or adhesive is applied to the film or tape according to requirements.

[0035] In particular, in the case of coupling machines, it is wise to heat the adhesive before the tape is coupled so that part of the solvent evaporates, transforming the adhesive from a practically liquid state, suitable for spreading on the tape, to a thicker state, suitable for sticking to the tape to be coupled and holding it in place.

[0036] For this reason, the tape to which adhesive has been applied is subject to a passage of hot air fed into the tunnel by the insufflators 7.

[0037] Advantageously, the funnel-shaped cavity enables a variation in the air speed and in the conditions of evaporation of the solvent during the introduction of air between the rear area 20b and the front area 20a of the tunnel.

[0038] In particular, a smaller section of the cavity creates a higher air speed and therefore more powerful solvent evaporation, which is advantageous in the tape exit area, while the best conditions in the tape entry area are less powerful in order to avoid the formation of crusts on the adhesive.

[0039] Another part of this invention is a cradle upon which the rollers used in machines for rotogravure printing and/or coupling to pull polyethylene films rest and in which they move, to restrict revolving friction.

[0040] It is a well known fact that one of the main problems with the coupling of revolving cylindrical bodies is caused by friction which, even when ball bearings with a very high rolling coefficient are used, leads to a series of problems which are perceivable as time goes by and are due also, under specific conditions of use, to dilations in the cylindrical bodies the rotation of which, in contact with the respective supports, generates variations in temperature, wear and tear and deterioration of the rotation.

[0041] We propose a support for bodies in reciprocal rotation which, thanks to the brand new composition and arrangement of the individual parts, correctly eliminates the abovementioned problems, improving the duration and rotational capacity and reliability of the cylinders

[0042] The roller 6 has a tang 102, said roller 6, being placed in rotation on a pair of revolving bodies 103, such as an outer ring of ball bearings for example, with a simple rest and gravitational contact.

[0043] The bearings 103 are hinged and mortised to a main support 104 and their surface is in contact with the tang 102 of the roller 6 made of suitable material, such as special steel with a surface coating of particularly hard material.

[0044] While the roller 6 rotates, heat is created thanks to the revolving friction between the roller 6 and the bearings 103, depending especially on the device which houses the roller, when high temperatures develop in said device. In order to eliminate the effects of the consequent thermal dilation, in the support 104 there is a special channel which leads to an outlet or nozzle 105 through which cooled air is insufflated.

[0045] Said outlet 105 is positioned so that the air flows over the group made up of the roller 6 and the bearings 103 in such a position as to cool the contact area between the roller and bearings, limiting the variation in temperature and the consequent thermal dilation.

[0046] In another version, the tang 102 of the roller 6 has a shoulder 110, preferably in the form of a pair of rings. In said version, the roller 6 is guided on just one side, allowing the production of the effects of thermal dilation only on the opposite side which remains free.

[0047] Advantageously, said version can be used in processes requiring the application of aluminium foil.

[0048] There is therefore an increase in the utility of the connection in terms of reliability of use over a period of time.

[0049] Machine maintenance operations benefit enormously from the installation of the tunnel and support described above.

[0050] Often some of the adhesive runs from the film onto the rollers and gradually hardens due to the insufflation of hot air.

[0051] Maintenance is carried out by activating the machine lifting devices such as jacks 20, 22, lifting the cover to a set height, so that the cover can be horizontally moved.

[0052] Said horizontal movement devices are activated by moving the cover 2 horizontally to free access to the tunnel.

[0053] The rollers 6 are easily accessible along their whole longitudinal length, consenting simple and quick cleaning.

[0054] Alternatively, said rollers are lifted from the machine, without disassembling any parts as they gravitationally rest on the revolving bodies or bearings 103.

[0055] The rollers are cleaned outside the machine and then reassembled.

[0056] In another maintenance process, said rollers are replaced with clean rollers already prepared outside the machine.

Claims

1. Drying tunnel for printing and/or coupling machines comprising a lower structure (1) and an upper cover (2), said lower part (1) comprising a series of mechanisms and devices for moving rolls (3, 3a, 3b) of paper and/or film, characterised by the inclusion of vertical lifting devices (20, 22) for lifting said cover (2).

2. Tunnel according to claim 1, comprising devices to horizontally move the cover (2) suitable for horizontally moving said cover, making the tunnel accessible from above.

3. Tunnel according to claim 1 or 2, in which said cover (2) is supported, in a front area (20a) by at least one front jack (20) and, in a rear area (20b) by at least one rear jack, said jacks being suitable for lifting said cover (2).

4. Tunnel according to any of the previous claims, in which a cavity (30) of adjustable height is created between the inner surface of said cover (2) and said rollers (6).

5. Tunnel according to claim 4, in which said cavity (30) is funnel-shaped between said rear and said front areas.

6. Tunnel according to any of claim 3 to 5, in which aid jacks can be activated independently.

7. Tunnel according to claim 6, in which aid jacks can be activated mechanically.

8. Tunnel according to claim 6, in which said jacks are servo assisted.

9. Tunnel according to any of the previous claims, also comprising hot air insufflators (7).

10. Tunnel according to any of the previous claims, also comprising a cradle support in which the rollers rotate(6).

11. Tunnel according to claim 10, in which said support comprises at least one revolving body (103) on which a tang (102) of said roller (6) rests gravitationally.

12. Tunnel according to claim 11, in which said revolving body is a ball bearing (103).

13. Tunnel according to claim 11 or 12, in which the point of contact between the tang (102) of the roller (6) and the bearings (103) is covered by a jet of cooled air issued by a nozzle (105).

14. Tunnel according to claim 13, in which said nozzle (105) is connected to a channel fitted in the support (104) of the bearings (103).

16. Tunnel according to claim 15, in which said support comprises a shoulder (110) on one side of the roller (6).

17. Printing and/or coupling machines comprising a tunnel according to any of the previous claims.

18. Method of drawing-in a film, for application to a coupling machine in accordance with claim 17, comprising the following phases:

- vertically lifting the cover 82) of the tunnel;

- inserting a drawing-in bar connected to the head of the film in a rear area (20b) of the machine, arranging it on said rollers;

- activating said rollers until said bar is positioned in a front area of the machine;

- lowering said cover.

19. Method of maintenance of a machine in accordance with claim 17, comprising the following phases:

- lifting the cover to a height so that the cover can be horizontally moved;

- horizontally moving the cover to make the tunnel accessible from above;

- performing maintenance operations on the rollers.

20. Method according to claim 19, in which the roller maintenance phase comprises replacement of said rollers with clean rollers.

21. Cradle support for the rotation of rollers made up of a roller (6) with a tang (102) destined for resting gravitationally on a pair of revolving bodies (103),characterised by the fact that the point of contact between the tang (102) and the revolving bodies (103) is covered by a jet of cooled air issued by a nozzle (105).

22. Support according to claim 21, in which said nozzle (105) is connected to a channel fitted in the support (104) of the revolving bodies (103).

23. Support according to claim 21 or 22, in which said revolving bodies are ball bearings.

24. Support according to any of claims 21 to 23, in which the rear part of the revolving bodies (103) which comes into contact with the tang (102) of the roller (6) is covered with special hardened steel.

25. Printing and/or coupling machined comprising a support according to any of claims 21 to 24.

Drawing