EP1352691B1 - Rotary applicator head - Google Patents

Description

The invention relates to a gun for applying liquid media such as liquefied thermoplastics or molten hot melt adhesives on a relatively movable to the applicator head material web, with a housing, with a roller chamber in the housing in which a roller slide is rotatably driven, and with a slot nozzle for dispensing of medium which is controllable by the roller slide and extends transversely to the direction of movement of the material web. In this case, the application head can be arranged at a distance or in contact with the material web,

An order head of this kind is from the DE 197 57 238 C2 known. In this case, axially parallel surface grooves are formed on the roller slide, which produce an order of liquid medium in a line shape transversely to the direction of movement of the material web.

US 3,332,580 A discloses a fluid applicator valve which comprises a roller oscillating in a cylindrical bore. In the roller a plurality of radially aligned through holes are arranged, through which the fluid exits. A shoe is inserted into each bore and biased radially outwardly so that each shoe is pressed against the inner wall of the cylindrical bore.

Application heads of the aforementioned type are always used in many applications, where material webs are to be prepared for lamination to a substrate. In order to keep the specific consumption of liquid medium low and at the same time ensure an extremely even distribution of the medium, an intermittent order is applied to represent a job image in raster form. If the web is separated rapportwise by a knife, the cuts must be made in each case between two order lines of liquid medium to prevent sticking of medium to the knife.

Proceeding from this, the object of the invention is to provide an application head of the type described above, which ensures extremely selective line application of liquid medium to material webs.

• einen inneren Hohlraum, dem flüssiges Medium zugeführt werden kann,
• eine Zylinderoberfläche
• erste Oberflächennuten in der Zylinderoberfläche, denen flüssiges Medium zugeführt werden kann und die drehstellungsabhängig mit der Schlitzdüse kommunizieren können,
• radiale Austrittsbohrungen vom inneren Hohlraum bis in die ersten Oberflächennuten, und
• zweite Oberflächennuten in der Zylinderoberfläche, die Verschlußleisten aufnehmen, die an der Oberfläche der Walzenkammer mit Vordruck anliegen, wobei jeder ersten Oberflächennut eine zweite Oberflächennut so zugeordnet ist, daß sie bei Drehung des Walzenschiebers der ersten Oberflächennut nacheilt.

The solution to this is that the roller slide has the following features:

• an internal cavity, to which liquid medium can be supplied,
• a cylinder surface
• first surface grooves in the cylinder surface, to which liquid medium can be supplied and which can communicate with the slot nozzle depending on the rotational position,
• radial exit holes from the inner cavity to the first surface grooves, and
• second surface grooves in the cylinder surface receiving shutter strips abutting the surface of the roller chamber with pre-pressure, each first surface groove having a second surface groove associated therewith so as to lodge with the first surface groove upon rotation of the roller valve.

This prevents that after passing a first surface groove at the feeders to the slot nozzle from the shell-shaped gap between the roller slide and roller chamber whose thickness is of the order of 2/100 mm, liquid medium flows into said feeds. Rather, each time after passing a first surface groove on the leads to the slot nozzle in the housing, the inlet openings are sealed to the feeders upon arrival of an inserted in a second surface groove sealing strip of this, so that a subsequent flow of medium from the shell-shaped gap is prevented in the inlet openings. After passing through the sealing strip thus sets on arrival of the next first surface groove a precisely sized entry of liquid medium in the feeders, which leads to sharply limited applications of liquid medium from the slot nozzle. The order lines of liquid material on the material web are thus sharply limited. Accordingly, clean cuts without contamination of the knife are possible even in closely spaced order lines on the web. Also for them Further processing of the material web are the clean limited jobs on liquid medium advantageous.

In a particularly favorable manner, the second surface grooves with the inserted sealing strips occupy substantially the entire cylinder surface of the roller slide between in each case two first surface grooves for supplying medium. Hereby a pressing of the elastically supported closure strips is maintained at the feeders for the entire period between the passage of two first surface grooves. The surfaces of the closure strips are cylindrical to adapt to the surface of the roll chamber. In a favorable embodiment it is provided that radial outlet holes for liquid medium from the inner cavity to the second surface grooves lead to increase the contact pressure of the sealing strips on the surface of the roller chamber by the pressure of the liquid medium.

In conventional design, the surface grooves can be performed axially parallel, this applies to first and second surface grooves and accordingly for the sealing strips. If the first surface grooves form curved lines and in particular form closed lines, the second surface grooves can be supplemented with the end strips to these lines and in particular cover larger areas inside and outside of said closed lines on the cylinder surface of the roller slide. If necessary, the large-area second surface grooves can also accommodate multi-part closure strips.

An applicator head according to the invention has the advantage that the control of the medium at the inlet openings to the feeders with clean breaks through the sealing strips takes place, so that the accuracy of the metering is not adversely affected by the viscosity of the medium or the elasticity of the medium. Due to the precise supply of the slot nozzle with medium from the inside of the roller slide out good order results can be achieved over the entire length of the gun without interference.

The representation of grid points transversely to the direction of movement of the web can be generated by using a corresponding nozzle aperture with individual holes at a small distance in the slot nozzle. A single feed in the housing preferably communicates with a single bore in the nozzle diaphragm. If the use of such a nozzle diaphragm is dispensed with, a line application is produced in each case transversely to the direction of movement of the material web when axially parallel grooves are used.

In a first embodiment, a radial bore in the housing is provided at least at one end of the housing and an annular channel between the roller slide and roller chamber is formed, which is connected to the bore in the housing and there are radial feed holes in the roller slide in the plane of the annular channel executed with are connected to the inner cavity and serve as a supply for medium. Said at least one annular channel can be formed by an annular groove in the roll surface and / or by a circumferential groove in the roll chamber bore.

In an alternative embodiment, the roller slide is provided with at least one axially exiting from the housing pin in which an axial bore is made, which is connected to the inner cavity and serves as a supply of medium to the inner cavity. Hereby, the housing design is particularly simple, but a rotating seal must be provided in the region of the pressurized medium supply.

Regardless of whether a supply of medium to the inner cavity occurs only at one or both ends of the roller valve, a corresponding small increase in the diameter of the radial exit holes to the surface grooves over the roller slide length can compensate for a small pressure loss in the medium over the roller slide length be provided. A leakage of medium from the housing can be prevented by the use of conventional shaft seals at the ends of the roller slide with respect to the roller chamber.

Figur 1

zeigt einen Auftragskopf mit einer Materialbahn in perspektivischer Ansicht;

Figur 2

zeigt einen Walzenschieber mit achsparallelen ersten und zweiten Oberflächennuten als Einzelheit in perspektivischer Ansicht;

Figur 3

zeigt einen Auftragskopf mit Walzenschieber im Querschnitt;

Figur 4

zeigt einen quergeschnittenen Auftragskopf mit quergeschnittenem Walzenschieber in perspektivischer Ansicht;

Figur 5

zeigt einen Auftragskopf mit quergeschnittenem Gehäuse und vollständigem Walzenschieber.

A preferred embodiment of the invention will be explained below with reference to the drawings.

FIG. 1

shows a gun with a material web in perspective view;

FIG. 2

shows a roller slide with axially parallel first and second surface grooves as a detail in a perspective view;

FIG. 3

shows an application head with roller slide in cross section;

FIG. 4

shows a cross-cut application head with cross-cut roller slide in a perspective view;

FIG. 5

shows a gun with cross-cut housing and complete roller slide.

FIG. 1 shows an applicator head 11 of elongated cubic shape. From the housing 12 of the applicator head 11 protrudes one end of a roller slide 13. The direction of rotation of the roller slide 13 is indicated by an arrow 14. The end of the roller slide 13 has a pin 15. On the housing 12 nozzles 16 are attached, via which, as indicated by arrows 17, liquid medium is supplied. At the bottom of the housing 12, a slot nozzle 18 can be seen, from which a spray curtain 19 emerges. The spray curtain 19 strikes a material web 22 whose direction of movement is symbolized by an arrow 23. The spray curtain 19 generates a job grid 24 on the web 22, which shows substantially Linienzüge transverse to the direction of movement. Within the lines, individual lines are visible in the direction of movement. It follows that the slot nozzle 18 comprises a diaphragm with individual outlet openings whose distance determines the distance of the individual lines transverse to the direction of movement of the web 22.

Like in the FIG. 2 To recognize the roller slide 13 has on its cylindrical surface 35 a plurality of first axial grooves 27 in which radial bores 28 end. The first axial grooves 27 are on the radial bores 28 of a inner cavity supplied with liquid medium. The inner cavity in turn is supplied via a circumferential groove 25 with radial bores 26 with liquid medium. The circumferential groove 25 communicates with one of the radial connection 16 in the housing 12 in open connection. Another circumferential groove with radial holes of the same kind is located at the opposite end of the roller slide. Parallel to the first axial grooves 27 are in the direction of rotation relative to these trailing second axial grooves 31 with a smaller number of radial bores 32. In this closure strips 33 are used, which are supported by coil springs 34 elastic.

As further in the FIGS. 3 and 4 can be seen, the radial bores 28 are supplied via an inner cavity 29 with liquid medium. About the radial bores 28, the axial grooves 27 are constantly filled with medium. Likewise, the axial grooves 31 are supplied via the radial bores 32 with small amounts of liquid medium, which should ensure a low throughput to prevent hardening of the medium in the axial grooves 31 and thus setting the sealing strips 33. The closure strips 33 are supported by helical compression springs 34 in the axial grooves 31 to abut with pre-pressure on the surface of the roller chamber 20. As can be seen in cross section, the housing 12 encloses the roller slide 13 with a cylindrical roller chamber 20, from which radial bores 21 lead to the slot nozzle 18. In the slot nozzle, an outlet opening 30 is designated, which communicates with one of the feed holes 21 in the housing 12.

In FIG. 5 are details of Figures 2 and 4 shown in combination. The housing 12 is shown cut away at the front, wherein the roller slide 13 is pulled out of its intended position to the front. In the intended position, a bore 36 for the nozzle 16 and the circumferential groove 25 would lie with the radial bores 26 in a common axis normal plane.

LIST OF REFERENCE NUMBERS

11

gun

12

casing

13

roller slide

14

arrow

15

spigot

16

radial stub

17

arrow

18

slot

19

spray curtain

20

rolling chamber

21

radial bore

22

material hole

23

arrow

24

order grid

25

circumferential groove

26

radial bore

27

axial groove

28

radial bore

29

cavity

30

outlet opening

31

axial groove

32

radial bore

33

closure band

34

coil spring

35

cylinder surface

36

drilling

Claims (9)

1. An applicator head (11) for applying liquid media such as liquefied thermoplastics or melted hot melt adhesives to a web of material (22) which is movable relative to the applicator head, said head having a housing (12) and having in the housing a roll chamber (20) in which a roll slider (13) is mounted such that it can be rotary-driven, and having, for delivering liquid medium, a slot nozzle (18) which is controllable by the roll slider (13) and which extends transversely to the direction of travel of the web of material,
   the roll slider (13) having the following features:

   - an inner cavity (29) to which liquid medium can be supplied,

   - a cylindrical surface,

   - first surface grooves (27) in the cylindrical surface, which grooves can be supplied with liquid medium and which, according to the rotational position, can communicate with the slot nozzle (18),

   - radial outlet bores (28) from the inner cavity (29) to the first surface grooves (27),

   characterised by

   - second surface grooves (31) in the cylindrical surface, which grooves accommodate shut-off strips (32) [sic - recte 33] which rest against the surface of the roll chamber (20) with inlet pressure, each first surface groove (27) having an associated second surface groove (31) such that, when the roll slider (13) rotates, the second surface groove follows the first surface groove.
2. An applicator head according to claim 1,
   characterised in that the second surface grooves (31) and the shut-off strips (32) [sic - recte 33] lying therein occupy substantially the whole of the cylindrical surface (35) between each pair of first surface grooves (27).
3. An applicator head according to claim 1,
   characterised in that the surface grooves (27, 47, 67) are in the form of axis-parallel grooves.
4. An applicator head according to claim 2,
   characterised by radial outlet bores (32) for liquid medium from the inner cavity (29) to the second surface grooves (31).
5. An applicator head according to any one of claims 1 to 4,
   characterised in that, at least at one end of the housing (12), there is provided a neck (16) in the housing and there is formed between the roll slider (13) and the roll chamber (20) an annular channel which communicates with the neck in the housing, and
   in that there are formed in the roll slider (13), in the plane of the annular channel, radial supply bores (26) which communicate with the inner cavity (29) and are for supplying liquid medium.
6. An applicator head according to any one of claims 1 to 4,
   characterised in that, in the roll slider (13), at least at one end, there is formed an axial bore which communicates with the inner cavity (29) and is for supplying liquid medium, the axial bore being formed, in particular, in a journal (15) which extends axially out of the housing.
7. An applicator head according to claim 5,
   characterised in that the at least one annular channel is formed by an annular groove in the roll chamber surface.
8. An applicator head according to claim 5,
   characterised in that the at least one annular channel is formed by a circumferential groove (25) on the roll slider (13).
9. An applicator head according to any one of claims 1 to 8,
   characterised in that there is inserted in the slot nozzle (18) a diaphragm having a plurality of outlet apertures for liquid medium, the outlet apertures (36) [sic - recte 30] being individually connected to radial supply bores (21) in the housing (11) [sic - recte 12], which bores extend from the roll chamber (20).

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