EP0577136B1 - Apparatus for applying glue - Google Patents

Abstract

In an apparatus for applying glue, having a heatable storage shaft for the glue with a lower discharge opening closable by means of at least one adjusting slide, in order to make rapid and simple switching from one type of glue to another and cleaning possible with a technically simple construction, the storage shaft (1) has, over its height, in each case a substantially constant cross-section and consists of at least two shaft parts (2, 3) which are sealingly connected to one another along at least one separating plane (4) running approximately parallel to the shaft axis by means of a quick-release connecting device. <IMAGE>

Description

The present invention relates to a device for applying adhesive, with a heatable storage shaft for the adhesive with a lower dispensing opening which can be closed by at least one adjusting slide, and an application doctor arranged in the region of the dispensing opening.

When laminating, wrapping and gluing, it is necessary to apply adhesive over the entire surface. It is essential that the application of the adhesive takes place absolutely uniformly in a predetermined, adjustable layer thickness and as a function of the adhesive used, the workpiece parameters and the type of adhesive operation.

Depending on the type of adhesive and area of application, a wide variety of devices and procedures are known for applying adhesive. So-called wide slot nozzles (see, for example, DE-40 10 262), application rollers (see, for example, DE 33 00 008) or pouring processes (see, for example, DE-28 20 881) are used for adhesive application.

For processing hot melt adhesive based on PUR and EVA, devices of the generic type are known which work with an application doctor blade which is fed via a heated storage shaft. Such a device is known for example from DE-27 37 728. In order to adjust the application width of the adhesive on the material web, at least one adjustment slide is provided in such devices, which is manually adjusted to the desired application width.

Compared to devices working with slot dies, application rollers or pouring processes, devices of the generic type have the advantage that their construction is relatively simple from a technical point of view.

However, they have the disadvantage that changing from one type of adhesive to another type of adhesive and cleaning is very complex and requires a lot of assembly work.

It is therefore an object of the present invention to develop a device of the generic type in such a way that, with a technically simple structure, it is possible to switch from one type of adhesive to another and to clean it quickly and easily.

This object is achieved in that the storage shaft has a substantially constant cross-section over its height and consists of at least two shaft parts which are closely connected to one another along at least one separating plane running approximately parallel to the shaft axis via a quickly releasable connecting device.

The invention is based on the idea of designing the device in such a way that in particular the storage shaft can be dismantled in a simple manner without tools and above in addition, the surfaces that come into contact with adhesive are as flat as possible, that is to say are formed without shoulders, edges, undercuts or the like. Even surfaces can be formed in a technically simple manner for the areas that come into contact with adhesive if the storage shaft according to the invention has an essentially constant cross section over its height.

The quick-release connection device can be designed in a variety of ways. For example, if screw connections are used for the manhole parts, toggle arrangements can be provided which enable easy and quick loosening by hand. However, it is also possible to design the connecting device with eccentric clamping devices, toggle lever tensioning devices or the like in order to realize a quickly releasable connection of the shaft parts.

A particularly simple configuration results if the storage shaft consists of only two shaft parts, since in such a case the connecting device can be designed to be technically simple. The two shaft parts can be of the same design or have a different shape.

A particularly simple storage slot design is achieved if the clear cross section is rectangular. In such a case, it is advantageous to design the one shaft part as an essentially U-shaped channel which forms three adjoining side walls of the shaft. With such a design, the other shaft part can be designed as a flat plate, which covers the opening of the U-shaped channel to form the fourth side wall of the shaft.

A particularly problem-free disassembly of the storage shaft is achieved if each of the shaft parts has its own heating device, which is separate from the other shaft part, each with its own separate power supply. In such a case, with appropriate dimensioning of the supply line lengths, no electrical connection or disconnection work needs to be carried out when cleaning the shaft or when changing from one type of adhesive to the other.

For most industrial applications, it is advantageous that the device is equipped with devices for level control of the adhesive, which protrude into the storage shaft. These devices can be designed and arranged in a wide variety of ways. It is advantageous if the device is equipped with a cover which covers the filling opening for the adhesive which is arranged at the upper end of the storage shaft and opposite the dispensing opening. In such a case, it is advantageous to attach the level control devices to the cover, since when the cover is loosened and removed, the level control devices are automatically removed from the area of the storage shaft so that it can be easily dismantled.

It is expedient to produce the cover from insulating material, such as Teflon or the like.

Basically, the storage shaft can be heated in a variety of ways. Heating with heating cartridges, which can be inserted into the openings provided in the shaft parts, has proven effective. In order to ensure absolutely identical temperature conditions in all shaft areas, it is expedient, if necessary, also to apply the doctor blade and / or other elements in the area of the to heat the lower outlet opening provided for the adhesive.

In principle, the application doctor blade can be designed in a wide variety of ways for the respective application. It is advantageous if the application squeegee on its order side, i.e. the side facing the surface to be coated is equipped with a smoothing surface.

It is particularly advantageous, even if there is a sudden glitch in the event of a malfunction, an interruption in production, an emergency situation or a change to a different web of material, if the lower dispensing opening can be closed quickly, since previously the known adjustment slide had been used to this end over a long travel range must be manually moved to an opposite side wall of the lower dispensing opening.

In large devices of this type, two opposing adjustment slides for adjusting the application width are arranged at the lower dispensing opening. To close, an operator must first operate the one setting slide over the long travel ranges and then insert the second setting slide from the other side.

A closing device provided in the area in the lower dispensing opening, with which the lower dispensing opening can be closed regardless of the position of the adjusting slide or sliders, enables simple operation when the system is switched off or on again.

The new closing device reduces the previous double function of the known adjusting slide, ie closing the dispensing opening and setting the application width, to the function of regulating the adhesive application width and with a quick one When the lower dispensing opening is closed or reopened, the preset application width of the adhesive application remains unchanged in the event of an abrupt stop or restart, since only very short adjustment paths are required to close or reopen the lower dispensing opening. As a result, when the closure is closed and when the dispensing opening is reopened, there are no longer any sections with a narrowing adhesive application width, which was unavoidable in the known device when closing and reopening the dispensing opening.

A closing device provided in the area of the lower dispensing opening, with which the lower dispensing opening can be closed regardless of the position of the adjusting slide or sliders, enables simple operation when the system is switched off or on again.

With the new locking device, the previous double function of the known adjustment slide, i.e. Closing the dispensing opening, as well as setting the application width, is reduced to the function of regulating the adhesive application width and if the lower dispensing opening is closed or reopened quickly, the preset application width of the adhesive application remains unchanged in the event of an abrupt stop or restart, because the closure or reopening is now complete only very short adjustment paths are required at the bottom dispensing opening. As a result, when the closure is closed and when the dispensing opening is reopened, there are no longer any sections with a narrowing adhesive application width, which was unavoidable in the known device when the dispensing opening was closed and reopened.

A particularly simple embodiment of the closure device according to the invention is obtained if the application squeegee is displaced vertically by pneumatic lifting cylinders, in particular short-stroke cylinders, under guidance in elongated holes, against the closure plate forming a surface, as a result of which a rapid closing or reopening of the lower dispensing opening is possible. The required travel of the application doctor blade is very small, which explains the very fast closing or reopening of the dispensing opening.

A further simple embodiment of the closing device is obtained if the closing plate forming a surface is horizontally displaced by means of pneumatic lifting cylinders, in particular short-stroke cylinders or the like, against the longitudinal edge of the application doctor blade, as a result of which the lower dispensing opening can be closed or opened again very quickly.

In order to achieve a proper closure of the lower dispensing opening, it is advantageous to pretension the closing plate against a holding bar and the adjusting slide so that the closing plate lies perfectly flat on the holding bar and the adjusting slide. When moving the applicator blade, it abuts the sealing plate with the longitudinal edge extending over the width of the dispensing opening and bends it slightly resiliently downwards. The lower dispensing opening is thus sealed.

To seal the lower dispensing opening in a sealed manner, it is further advantageous to provide the longitudinal edge of the applicator knife, which extends over the width of the dispensing opening, with a slight bevel so that the sealing plate can bend downwards more easily when it hits the applicator knife.

A particularly advantageous embodiment of the device according to the invention for applying adhesive consists in providing the parts in which closure occurs relative to one another with an anti-stick coating, for example a Teflon coating or the like. This has the advantage that the parts when closing or Re-open the dispensing opening by moving it slightly against each other and adhesive residues can be easily removed.

Fig. 1

zeigt schematisch eine Vorderansicht eines ersten Ausführungsbeipiels einer erfindungsgemäßen Vorrichtung zum Auftragen von Klebstoff,

Fig. 2

zeigt schematisch einen Schnitt in der Ebene II-II der Fig. 1, und

Fig. 3

zeigt schematisch einen Schnitt in der Ebene III-III der Fig. 1.

Fig. 4

eine schematische Vorderansicht eines zweiten Ausführungsbeispiels der erfindungsgemäßen Vorrichtung mit verschiebbarer Auftragsrakel,

Fig. 5

einen schematischen Schnitt in der Ebene II-II der Fig. 4,

Fig. 6

eine schematische Vorderansicht eines dritten Ausführungsbeispiels der erfindungsgemäßen Vorrichtung mit verschiebbarem Verschlußblech;

Fig. 7

einen schematischen Schnitt in der Ebene III-III der Fig. 6,

Fig. 8

eine vergrößerte Darstellung der unteren Ausgabeöffnung des ersten Ausführungsbeispiels nach Fig. 5 mit offener Ausgabeöffnung, und

Fig. 9

eine vergrößerte Darstellung der unteren Ausgabeöffnung des zweiten Ausführungsbeispiels nach Fig. 5 mit geschlossener Ausgabeöffnung.

In the following three embodiments of the invention are described and explained in more detail with reference to the accompanying drawings for further explanation and for better understanding.

Fig. 1

schematically shows a front view of a first exemplary embodiment of a device for applying adhesive according to the invention,

Fig. 2

shows schematically a section in the plane II-II of Fig. 1, and

Fig. 3

shows schematically a section in the plane III-III of FIG. 1st

Fig. 4

2 shows a schematic front view of a second exemplary embodiment of the device according to the invention with a movable application doctor,

Fig. 5

3 shows a schematic section in plane II-II of FIG. 4,

Fig. 6

is a schematic front view of a third embodiment of the device according to the invention with a sliding closure plate;

Fig. 7

6 shows a schematic section in the plane III-III of FIG. 6,

Fig. 8

an enlarged view of the lower dispensing opening of the first embodiment of FIG. 5 with open dispensing opening, and

Fig. 9

an enlarged view of the lower dispensing opening of the second embodiment of FIG. 5 with the dispensing opening closed.

As can be seen in particular from FIG. 2, the device for applying adhesive according to the invention has a storage shaft 1 which has a constant cross section over its height.

As can be seen in particular from FIG. 3, the storage shaft 1 is formed by two shaft parts 2 and 3, which adjoin one another along a parting plane 4 running parallel to the shaft axis. The shaft part 3 is designed as an essentially U-shaped channel which forms three adjoining side walls 5, 6 and 7 of the shaft, which in the present exemplary embodiment are integrally connected to one another.

The other shaft part 2 in turn is essentially designed as a flat plate, which covers the U-shaped channel formed by the side walls 5, 6 and 7 of one shaft part 3 and in this way forms the fourth side wall 8 of the storage shaft 1.

The two shaft parts 2 and 3 are tightly connected to one another by a connecting device (not shown in the figures) in the region of the parting plane 4. Of the connecting device, only toggles 9 are shown in FIG. 2, via which the connecting device can be released and thus one shaft part 3 can be lifted off the other shaft part 2.

On the side facing away from the shaft part 3, the shaft part 2 has two tabs 10, via which the device is articulated on the respective machine (not shown).

As can be seen in particular from FIG. 2, a closure strip 12 is fastened at the lower end of the shaft part 2 by means of screws 11.

The shaft part 3 in turn carries at its lower end an applicator knife 13 which, together with the sealing strip 12, forms a lower discharge opening 14 for the storage shaft 1. In Fig. 2, this dispensing opening is closed by a squeegee slide 15, which carries at one end (cf. FIG. 1) a handle 16 by means of which it is pulled out to the left in order to open the dispensing opening 14 in the direction of arrow 17 in FIG. 1 can be.

With the squeegee slide 15 it is not only possible to open or close the dispensing opening 14 for the adhesive, but also to set the application width for the adhesive application, as can be seen from FIG. 2.

As is apparent from Fig. 1, the doctor blade 13 is fastened to the shaft part 3 with three nuts 18. These nuts 18 each act on a spring washer 19, which is supported on the applicator blade 13 on the side facing away from the shaft part 3.

As can be seen from FIG. 2, each nut 18 is screwed onto a bolt 20, which is seated in a threaded bore of the shaft part 3. In the area of the bolts 20, the application doctor 13 is each equipped with bores 21, the diameter of which is considerably larger than the diameter of the bolt 20. In this way, the application doctor 13 can move vertically downwards and upwards on the shaft part 3 to adjust the adhesive layer thickness be moved.

To adjust the position of the application doctor 13, the device has two adjustment aids 22 of known design, each of which is equipped with an adjusting screw 23, by means of which the application doctor 13 can be finely adjusted.

The application doctor blade 13 is equipped on its application side facing the workpiece, not shown, with a smoothing surface 31 (see FIG. 2).

As can be seen in particular from FIG. 2, the shaft parts 2 and 3 and the application doctor 13 are each equipped with bores 24. These holes are used in a known manner for receiving heating cartridges and together form the heating device of the device.

The filling opening 25 opposite the dispensing opening 14 at the upper end of the storage shaft 1 is covered with a cover 26. As can be seen from FIG. 1, this cover is fastened to the storage shaft with easily detachable knurled nuts 27. The cover 26 preferably consists of an insulating material, such as Teflon, and carries various devices, which are shown schematically in FIG. 1.

Thus, a feed line 28 for the adhesive is arranged in the cover 26, via which the adhesive is fed into the storage shaft 1 in a known manner.

The cover 26 is also equipped with a protective gas connection 29, via which nitrogen, for example, can be fed into the upper part of the storage shaft 1 which is not filled with adhesive.

The lid also carries probes 30 and 31 for level sensing, ie for measuring the adhesive level within the storage well. These probes can be used, for example, as capacitive probes or control the level via a temperature difference measurement.

The fill level can also be scanned in a different way.

As already mentioned at the beginning, it is advantageous for each shaft part to have a heating device separate from the other shaft part, each with its own separate power supply. In the present exemplary embodiment, this is achieved in a simple manner in that the heating cartridges in the bores 24 of each shaft part 2 or 3 are combined and connected to the power supply via a common line.

To clean the device, it is only necessary in a first step to loosen and lift the cover 26 via the knurled nuts 27. As a result, the feed line 28, the protective gas connection 29 and the probes 30 and 31 are already uncoupled from the device without great effort.

In a second step, only the toggles 9 then have to be loosened, the squeegee slide 15 pulled out via the handle 16 in the direction of the arrow 17 and the two shaft parts raised. The surfaces that come into contact with adhesive are then completely exposed for cleaning. Assembly or disconnection work is not necessary for this.

5, a second embodiment of the device according to the invention comprises a front housing side 2 and a rear housing side 3, which form a storage slot 1. A heating device 20 for heating the adhesive is integrated in the front housing side 2 and the rear housing side 3. The storage shaft 1 is closed at the upper end with the cover 4 and has a lower discharge opening 1a at the lower end.

At the lower end of the dispensing opening, an application squeegee 5 is displaceably attached to the front housing side 2 by means of a plurality of bolts 18, disc springs 19 underneath, and Teflon-coated thrust washers 17, which are seated on the outer side of the application squeegee 5. An adjusting screw 14 is used to adjust the adhesive thickness on the material web to be provided with adhesive.

On the side of the device facing the material web, a holding strip 7 is firmly connected to the rear housing side 3. On the retaining strip 7, an L-shaped closing plate 8 is fastened by means of a number of screws 21 in such a way that the closing plate 8 presses against the holding strip 7 with slight pretension and lies flat against it. The width of the lower discharge opening 1 a formed by the sealing plate 8 and the application doctor 5 is limited by an adjusting slide 6. For this purpose, the adjusting slide 6 is slidably fitted between the holding bar 7 parallel to the plane of the material web.

The closing mechanism used to close the lower dispensing opening 1a is formed in this first exemplary embodiment by the movable application doctor 5 and the closing plate 8 fixedly attached to the housing. From Fig. 4 it can be seen that the doctor blade 5 is guided by a plurality of bolts 18 vertically with respect to the front side 2 of the housing. On the application knife 5 extending across the width, two lifting cylinders 22 are each provided with articulated bearings 23, which each engage in bolts 24 fixedly attached to the application doctor 5. The lifting cylinders 22 are firmly screwed to the front housing side 2.

From Fig. 4 it can be seen that the adjusting slide 6 is provided with a handle 26, and an adhesive application width marking 25.

A solid round rod 15 is arranged under the lower dispensing opening of the device for applying an adhesive so that the material web can slide under the sealing plate 8 and the adhesive is applied to the lower dispensing opening by means of the application doctor 5 on the material web.

In the event of an emergency situation, a change to a different material web with different dimensions, adjustment of a new application width of the adhesive or simply a malfunction, it is necessary to close the lower dispensing opening of the device very quickly in order to avoid unusable material sections, whereby the adjustment slide 6 predetermined application width of the adhesive application should not be changed. In the second exemplary embodiment according to FIGS. 4 and 5, the pneumatically operated lifting cylinders 22 are actuated for this purpose. These known lifting cylinders are pressurized with compressed air, as a result of which the application squeegee 5 is moved vertically by a very short travel path to the material web. The application doctor 5 abuts the closing plate 8 with its beveled longitudinal edge 5a facing the dispensing opening and bends it slightly resiliently downwards. As a result, the lower discharge opening of the storage shaft 1 is sealed. On the web of material, parallel to the longitudinal edge 5a of the application doctor 5, the adhesive application is completed in a straight line over the entire width.

When the system is restarted and adhesive is applied by means of the device according to the invention, the lifting cylinders 22 are in turn pressurized with compressed air and pull the application doctor back into its upper starting position. The lower dispensing opening 5 is opened again over the entire predetermined application width of the adhesive application. Thus, when starting up, a straight start of adhesive application, which extends parallel to the longitudinal edge 5a of the application doctor 5, is again formed.

FIG. 8 shows an enlarged illustration of the second exemplary embodiment with a movable application doctor 5 according to FIG. 5 with the lower output opening of the storage shaft 1 open.

FIG. 9 again shows an enlarged section of the second exemplary embodiment with a movable application doctor 5 according to FIG. 5, but the lower dispensing opening of the storage shaft 1 is closed here by the application doctor 5. In this illustration, the bend of the closure plate 8 is drawn exaggerated.

A third embodiment of the device according to the invention is shown in FIGS. 6 and 7. In this third exemplary embodiment, the applicator knife 5 is displaceably connected to the adjusting screw 14 on the front housing side 2 of the device according to the invention with the bolts 18 only for setting the adhesive application thickness. The lower closing plate 8 is connected to the retaining strip 7 by means of screws 10 which lie in elongated holes which run parallel to the material web transport direction. At the lower end of the closure plate 8, a strip 12 is firmly screwed to the closure plate 8 by means of screws 11. A plurality of lifting cylinders 13 are attached to this bar 12, which extends over the entire width of the lower dispensing opening 1a. The strip 12 extends over the entire width of the device according to the invention on the rear lower edge of the rear housing side 3 and is attached to be horizontally displaceable.

To close the lower dispensing opening of the device according to the invention, the lifting cylinders 13 are pressurized with compressed air, as a result of which the bar 12 moves horizontally toward the application doctor 5, whereby the closure plate 8 attached to it abuts the bevel 5a of the application doctor 5 and bends slightly resiliently downward. As a result, the lower discharge opening 1a of the storage shaft 1 becomes very large quickly closed. To open the lower discharge opening 1 a, the lifting cylinders 13 are pressurized with compressed air so that they move back into their original position, as a result of which the closing plate 8 releases the lower discharge opening 1 a of the storage shaft 1. As a result, the material web sliding on the round rod 15 is provided with an adhesive application which has a straight approach perpendicular to the transport direction of the material web.

Claims (22)

1. Apparatus for the application of adhesive, comprising a heatable storage shaft (1) for the adhesive having a lower discharge aperture (14) closable by means of at least one adjustment slide (6) and an application wiper (13) arranged in the region of the discharge aperture, characterized in that the storage shaft (1) has a substantially constant cross section throughout its length and consists of at least two shaft sections (2, 3) which are tightly connected to one another by mans of a quickly releasable connecting device along at least one separating plane (4) extending approximately parallel to the shaft axis.
2. Apparatus according to claim 1, comprising a storage shaft (1) for the adhesive consisting of two shaft sections, characterized in that the shaft sections (2, 3) have the same shape.
3. Apparatus according to claim 1, comprising a storage shaft (1) for the adhesive consisting of two shaft sections, characterized in that the shaft sections (2, 3) have a different shape.
4. Apparatus according to claim 3, comprising a storage shaft with a rectangular cross section, characterized in that the one shaft section (3) is formed as a substantially U-shaped trough which forms three adjoining side walls (5, 6, 7) of the shaft (1), and that the other shaft section is formed as a flat plate which covers the opening of the U-shaped trough to form the fourth side wall (8) of the shaft (1).
5. Apparatus according to claims 1 to 4, characterized in that each shaft section (2, 3) has its own heating device separate from the other shaft section and respectively with its own separate power supply.
6. Apparatus according to one or more of the preceding claims, characterized in that devices (30, 31) for controlling the level of the adhesive project into the storage shaft (1).
7. Apparatus according to claim 6, comprising a feed aperture (25) for the adhesive arranged at the upper end of the storage shaft opposite the discharge aperture (14), and a cover (26) covering the feed aperture, characterized in that the devices (30, 31) for controlling the level are secured to the cover.
8. Apparatus according to claim 7, characterized in that the cover (26) is of insulating material such as teflon or the like.
9. Apparatus according to claim 1, characterized in that the application wiper (13) is heated.
10. Apparatus according to claim 9, characterized in that the application wiper (13) is provided with a smoothening surface (31) on its application side.
11. Apparatus according to one or more of the preceding claims, characterized in that a closing device is provided in the region of the lower discharge aperture (1a) by means of which the lower discharge aperture can be closed independently of the position of the at least one adjustment slide (6).
12. Apparatus according to claim 11, characterized in that the closing device in the region of the lower discharge aperture (1a) is formed by the application wiper (5) and a closure plate (8) which is arranged at the lower discharge aperture (1a) on a side facing towards a material web.
13. Apparatus according to claim 12, characterized in that the application wiper (5) is vertically displaceable.
14. Apparatus according to claim 12 or 13, characterized in that the application wiper (5) can be brought into abutment with the closure plate (8) by means of vertical displacement so that the lower discharge aperture (1a) can be closed.
15. Apparatus according to claim 13 or 14, characterized in that the application wiper (5) is vertically displaceable by means of pneumatic stroke cylinders (22), in particular short-stroke cylinders or the like.
16. Apparatus according to claim 12, characterized in that the closure plate (8) arranged at the lower discharge aperture (1a) is horizontally displaceable.
17. Apparatus according to claim 16, characterized in that the closure plate (8) can be brought into abutment with the application wiper (5) by means of horizontal displacement so that the lower discharge aperture (1a) can be closed.
18. Apparatus according to claim 12, 16 or 17, characterized in that the closure plate (8) arranged at the lower discharge aperture (1a) is horizontally displaceable by means of pneumatic stroke cylinders (13), in particular short-stroke cylinders or the like.
19. Apparatus according to claim 12, 13 or 14, characterized in that the longitudinal edge of the application wiper (5) formed by the lower side facing the material web and by the side facing the discharge aperture (1a) is provided with a bevel (5a).
20. Apparatus according to claim 19 and 14 or 17, characterized in that the longitudinal edge of the application wiper (5) provided with a bevel (5a) can be brought into abutment with the end face of the closure plate (8) upon closing the discharge aperture (1a).
21. Apparatus according to one or more of the preceding claims, characterized in that the parts of the apparatus which slide relative to one another are coated with an anti-stick coating.
22. Apparatus according to one or more of the preceding claims, characterized in that the parts of the apparatus which come into contact with adhesive are coated with an anti-stick coating.

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