EP1623769B1 - Coating head - Google Patents

Description

The invention relates to a gun for applying a liquid medium, such as hot melt adhesive or cold glue, on a substrate, which comprises a housing which forms a chamber with a feed channel and with an outlet opening. Application heads of this type are used in particular for an intermittent application of the liquid, in particular sticky medium in the form of dots or beads on a guided past the application head web material.

From the DE 197 14 029 A1 is an application head of the type mentioned, which comprises a control member having a passageway and a rotatably driven spool. In this case, the passage channel is connected to the inlet side with a feed channel for molten hot melt adhesive and with a nozzle opening for the molten hot melt adhesive outlet side. During a 360 ° rotation, the spool releases the passageway at least once and closes it again.

From the DE 197 48 908 C1 For example, an application head for liquid media is known which has a nozzle needle which is axially displaceably mounted in the chamber and passes freely through the chamber. The nozzle needle emerges from the chamber and sits with its tip on a nozzle needle seat of the outlet nozzle. At its end opposite the nozzle needle seat, the nozzle needle is connected to an actuating device which serves for the axial displacement of the nozzle needle. By an oscillating movement of the nozzle needle, the outlet nozzle is alternately opened and closed, so that the liquid medium intermittently on a on the applicator head Applied medium is applied.

US 5,148,946 discloses a method and apparatus for providing a predetermined amount of liquid having the features of the preamble of claim 1. A rotatable shaft is disposed in a feed channel. The liquid is provided by rotating the rotatable shaft in a predetermined orientation in which a liquid flow is possible. After a certain amount of the liquid has been provided, the rotatable shaft is rotated through an angle of rotation to another orientation and the flow of liquid is stopped.

The DE 28 05 379 shows a jet head for generating a pulsating liquid radiation for massage, with a rotatably mounted in a housing the liquid jet periodically interrupting the interrupter rotor.

US 4,204,646 shows a showerhead with a rotor for effecting a pulsating jet flow or continuous spray delivery from the showerhead.

On this basis, it is an object of the present invention to provide a gun for liquid media, which ensures a long service life with high order speed, especially when intermittent order.

This object is achieved by a gun for applying a liquid medium, such as hot melt adhesive or cold glue, to a substrate having the features of claim 1.

Characterized in that the spool is rotationally driven and has at least one passage for the highly viscous medium, the outlet opening is released at least once during a 360 ° rotation of the spool and closed again. In this case, the advantage of the present embodiment is, in particular, that in the chamber in which the spool occupies the front side and this concludes, a pressure can be built up so that the liquid medium - at opaque with the outlet opening - with pressure from the Outlet is squeezed out. In this way, in particular with intermetierendem order a bead of adhesive with a uniform application pattern can be generated.

According to a preferred embodiment, it is provided that the outlet opening and the at least one passage are arranged axially parallel to the axis of rotation. This configuration makes it possible that several passages distributed over the circumference can be arranged in the spool.

The spool has multiple passages extending over different sized arcuate sections about the axis of rotation. To this Way can be applied per 360 ° rotation of the spool several adhesive dots, the adhesive dots can be different lengths. According to a further embodiment, a plurality of passages may be provided which have the same distance to the respective adjacent passage. By this embodiment, an adhesive seam is produced with uniform application pattern.

In concretization of the invention it is provided that the spool has a pressure surface which limits the interior of the chamber in the direction of the outlet opening and which can be acted upon by the entering into the chamber liquid medium. By applying the pressure surface of the spool this is pressed against the bottom of the chamber, whereby a formed by manufacturing inaccuracies between the spool and the bottom gap is kept low. The pressure surface of the spool is preferably designed annular or circular and corresponds approximately to a vertical axis to the rotational cross-sectional area of the chamber. In this way it is prevented that liquid medium passes through a gap between spool and side wall of the housing and the outlet opening.

According to a preferred embodiment, the housing comprises a cover and a bottom, wherein a shaft of the spool is mounted in the lid and the spool rests on the ground. The lid and the bottom form in the direction of the axis of rotation opposite end faces that define the chamber. The spool preferably has a bearing journal which is mounted on the axis of rotation in a bearing bore in the bottom of the housing. By the storage of the spool above and below the chamber bending moments in the spool are kept low.

According to a preferred embodiment of the spool has a spherical portion-shaped control surface which rests on a corresponding hollow spherical bottom of the chamber. According to an alternative embodiment, the spool may also have a tapered control surface which rests on a corresponding hollow conical bottom of the chamber. According to a further alternative, the spool is disc-shaped and lies on the flat bottom the chamber up. In this case, the at least one passage can be designed in the form of an outwardly open circular cutout. Through this round outbreak, the liquid medium passes in a corresponding rotational position of the spool from the chamber into the outlet opening.

According to a preferred embodiment, the spool has an inner channel with an inlet and an outlet for the passage of compressed air, wherein the input is constantly acted upon by compressed air and the output is connected in a rotational position of the spool with the outlet opening. In this case, the channel preferably extends through the shaft of the spool. If the outlet opening of the channel coincide with the outlet opening of the housing, residues of the liquid medium from the outlet opening and the outlet nozzle can be pressed out by the compressed air. In this way, a clean and uniform adhesive seam is produced.

In a preferred embodiment, the bottom of the housing facing the end of the spool is designed spherical segment and adapted to the corresponding hollow spherical bottom of the housing. However, the bottom end of the spool may also have any other, adapted to the bottom of the housing mold. Preferably, the outlet opening and the mouth of the at least one passage are arranged on the axis of rotation. After a preferred embodiment, the feed channel is arranged in a side wall of the housing and the inlet of the passage in the peripheral surface of the spool.

Fig. 1

eine erste Ausführungsform eines Auftragskopfes

1. a) im Längsschnitt;
2. b) im Querschnitt gemäß Schnittlinie I-I aus Figur 1 a);

Fig. 2

eine Variante des Auftragskopfes aus Figur 1

1. a) im Längsschnitt;
2. b) im Querschnitt gemäß Schnittlinie II-II aus Figur 2 a);

Fig. 3

eine zweite Ausführungsform eines Auftragskopfes

1. a) im Längsschnitt;
2. b) im Querschnitt gemäß Schnittlinie III-III aus Figur 3 a);

Fig. 4

eine Variante des Auftragskopfes aus Figur 3

1. a) im Längsschnitt;
2. b) im Querschnitt gemäß Schnittlinie IV-IV aus Figur 4 a);

Fig. 5

eine dritte Ausführungsform eines nicht erfindungsgemäßen Auftragskopfes;

1. a) im Längsschnitt;
2. b) im Querschnitt gemäß Schnittlinie V-V aus Figur 5 a);

Fig. 6

eine vierte Ausführungsform eines nicht erfindungsgemäßen Auftragskopfes;

1. a) im Längsschnitt;
2. b) im Querschnitt gemäß Schnittlinie VI-VI aus Figur 6 a);

Fig. 7

eine fünfte Ausführungsform eines nicht erfindungsgemäßen Auftragskopfes

1. a) im Längsschnitt;
2. b) im Querschnitt gemäß Schnittlinie VII-V II aus Figur 7 a);

Preferred embodiments will be explained with reference to the following drawings. Herein shows

Fig. 1

a first embodiment of an applicator head

1. a) in longitudinal section;
2. b) in cross section according to section line II FIG. 1 a) ;

Fig. 2

a variant of the order header FIG. 1

1. a) in longitudinal section;
2. b) in cross section according to section line II-II FIG. 2 a) ;

Fig. 3

a second embodiment of an applicator head

1. a) in longitudinal section;
2. b) in cross section according to section line III-III FIG. 3 a) ;

Fig. 4

a variant of the order header FIG. 3

1. a) in longitudinal section;
2. b) in cross-section according to section line IV-IV FIG. 4 a) ;

Fig. 5

a third embodiment of a non-inventive applicator head;

1. a) in longitudinal section;
2. b) in cross-section according to section line VV FIG. 5 a) ;

Fig. 6

A fourth embodiment of a non-inventive applicator head;

1. a) in longitudinal section;
2. b) in cross-section according to section line VI-VI FIG. 6 a) ;

Fig. 7

A fifth embodiment of a non-inventive applicator head

1. a) in longitudinal section;
2. b) in cross-section according to section line VII-V II FIG. 7 a) ;

The FIGS. 1a) and 1b ), which will be described together below, show a gun 1 with a housing 2, which has a chamber 3 with a feed channel 4 and an outlet opening 5, and a spool 6. The spool 6 is rotatably mounted in the chamber 3 and comprises a The housing 2 is cup-shaped and has a cover 9, which closes the housing at the top, and a bottom 14. In the lid 9, a bearing 11 is provided which rotatably holds the shaft 7 of the spool 6. The bearing 11 is held by a retaining ring 12 axially fixed in the lid 9. On the bottom side, the spool 6 a bearing pin 13 which is seated in a corresponding bearing bore in the bottom 14 of the housing 2 for purposes of storage.

The spool 6 is designed spherical segment, wherein the shape of the spool 6 is adapted to the hollow spherical inner surface of the bottom 14 forming wall of the housing 2. In this case, a gap 21 is formed between a control surface 26 of the spool 6 and the bottom 14 due to manufacturing tolerances. The spool 6 has at its the feed channel 4 facing the end of a flat pressure surface 22 whose cross section corresponds to the cross section of the chamber 3. In the chamber 3 by the supply channel 4 incoming high viscosity sticky medium, in particular hot melt adhesive or cold glue, generated in the chamber 3 an overpressure, so that the pressure surface 22 of the spool 6 is acted upon in the direction of the bottom 14 of the housing 2. This is represented by the pointing towards the bottom 14 arrow 29. In the spool 6, two first passages 15, 17 are provided in the form of holes and a lying between these second passage 16 in the form of a slot. In this case, the second passage 16 extends over a larger arc section α about the axis of rotation A than the first two passages 15, 17.

The passages 15, 16, 17 extend over the height of the spool 6 at a constant distance R parallel to the axis of rotation A and connect the chamber 3 to the outlet opening 5 of the housing 2. In this way, when the spool 6 is in a rotational position in which one of the passages 15, 16, 17 coincides with the outlet opening 5, adhesive from the chamber 3 through the corresponding passage and the outlet opening 5 is pressed through from the applicator head 1. In this case, an outlet nozzle 18 is attached to the housing 2 in the flow direction at the end of the outlet opening 5, through which the adhesive occurs. The outlet nozzle 18 is sealed relative to the housing 2 by means of a sealing ring 19. By means of the present embodiment with a plurality of passages distributed over the circumference of the control slide 6, it is achieved that an intermittent application of the adhesive in the form of dots and beads located between two points can be applied to a sheet material passed by the application head. In this case, the length of the applied beads can be adjusted or varied by the rotational speed of the spool. For applications in which a continuous adhesive application is to be generated, the spool 6 is brought into a position in which one of the first passages 15, 17 with the outlet opening 5 dekken. If the adhesive application is to be prevented over a certain distance, the spool valve 6 can be rotated into a position in which the spool valve 8 covers the outlet opening 5.

FIG. 2 shows a variant of an order header after FIG. 1 in longitudinal section and in cross section, wherein the structure substantially to the structure of the applicator head FIG. 1 equivalent. In this respect, reference is made to the above description. The same components are provided with the same reference numbers. Distinctive components are provided with two subscripts. Unlike the gun after FIG. 1 For example, the present application head 1 has a control slide 6 ₂ with a channel 23, which serves for the passage of compressed air through the outlet opening 5. The channel 23 extends from the inlet 27 in the flow direction of the compressed air initially on the axis of rotation A centered by the shaft 7 ₂ to the lower portion of the spool 6 ₂ , where he radially away from the axis of rotation A to a radius of the distance between the outlet opening 5 and axis of rotation A corresponds, runs and ends in the outlet 24.

The spool 6 ₂ can thus be converted into a rotational position in which cover the output 24 of the channel 23 with the outlet opening 5 of the housing. On In this way residues of the adhesive from the outlet opening 5 and the outlet nozzle 18 can be "shot out". This embodiment has the advantage that the adhesive jobs in intermittent operation of the application head, in which the order takes place in the form of dots or beads, are accurate and no adhesive threads are drawn between two application points. As in particular from FIG. 2b ), only one passage 15 is provided, which is offset from the exit 24 of the channel 23 by 180 ° about the axis of rotation A. By rotation of the spool 6 ₂ adhesive dots or adhesive beads are applied to a guided past the application head web material. In each case, a rotational position, pressed in the hot melt adhesive through the outlet opening 5 and the outlet nozzle 18, alternate with a rotational position in which the outlet opening 5 and the outlet nozzle 18 are blown open by the air flowing through the channel 23. In this way, a very clean adhesive seam is achieved.

In FIG. 3 a second embodiment of an applicator head according to the invention is shown, which essentially according to that embodiment FIG. 1 equivalent. In this respect, reference is made to the above description. The same components are provided with the same reference numbers. Distinctive components are provided with three subscripts. According to the present embodiment, the spool 6 is ₃ conical and the chamber 3 to the bottom 14 toward the final wall of the housing 2 designed in accordance with a hollow cone. This embodiment offers compared to those FIG. 1 the advantage of easier production. Between the conical spool 6 ₃ and the wall of the housing 2, a gap is formed. The spool 6 ₃ has a first passage 15 ₃ and an in the direction of rotation of the spool 6 ₃ adjoining the elongated second passage 17 ₃ . As a result of this embodiment, an adhesive seam can be applied to a material passed by the applicator head while the control slide is rotating, whereby the distance between an adhesive dot and a bead of adhesive is equal to the division ratio of the arcuate portions between the first passage 15 ₃ and the second passage 17 ₃ corresponds to a full revolution of the spool.

The gun according to FIG. 4 Issues a variant of the order header FIG. 3 with channel 23 for the passage of compressed air, wherein the structure substantially to the gun after FIG. 2 equivalent. In this respect, reference is made to the above description. The same components are provided with the same reference numerals and different components are marked with four subscripted reference numerals. Unlike the gun after FIG. 3 , the present application head 1 a spool 6 ₄ with a passage 23 having an input 27 and an output 24, which serves for the passage of compressed air through the outlet opening. 5 In a rotational position of the spool 6 ₄ , in which cover the output 24 of the channel 23 with the outlet opening 5 of the housing, residues of the adhesive from the outlet opening 5 and the outlet nozzle 18 can be pressed out by means of compressed air, resulting in the above-mentioned advantages.

In FIG. 5 is a further embodiment of an applicator head according to the invention with a housing 2, which forms a cylindrical chamber 3, and a disc-shaped control slide 6 ₅ shown. Moreover, the embodiment shown corresponds essentially to the gun after FIG. 1 , to the description of which reference is made. The disk-shaped control slide 6 ₅ has four regularly distributed over the circumference of first passages 15 ₅ which ensure an intermittent outflow of adhesive from the chamber 3 through the outlet opening 5 and the outlet nozzle 18 with a rotating spool 6. ₅ Characterized in that the passages 15 ₅ are arranged regularly distributed over the circumference, is - at a constant rotational speed of the spool - an adhesive seam produced whose adhesive dots each have the same distance from each other.

In the embodiment according to FIG. 6 , which in many parts follow the gun FIG. 5 corresponds, the spool 6 ₆ four radial arms 25, so that each formed between two arms passages 15 _{6 are formed} in the form of Randausnehmungen. In a rotational position in which none of the arms 25 covers the outlet opening 5, the chamber 3 is directly connected to the outlet opening, so that adhesive can pass unhindered from the applicator head through the outlet nozzle 18. The spool 6 ₆ is located on the bottom 14 of the housing 2.

Another embodiment shows FIG. 7 , It is shown an applicator head with a substantially cylindrical housing 2, which has a chamber 3 with a feed channel 4 and an outlet opening 5, in which a control slide 6 ₇ is seated rotatably about its axis of rotation A. The feed channel 4 is arranged in a side wall of the housing 2 and opens - in the illustrated rotational position of the spool 6 ₇ - in a passage 15 _{7 of} the spool 6. ₇ The passage 15 ₇ extends from the feed channel 4 in the direction of the bottom 14 of the housing 2 facing the end and opens on the axis of rotation A in the outlet opening 5 of the housing 2. As in the embodiment according to FIG. 1 , to the description of which reference is made, the end of the spool 6 ₇ is designed spherical segment and adapted to the hollow spherical inner surface of the bottom 14 forming wall of the housing 2. In this case 26 of the control slide 6 ₇ and the bottom 14 is formed a gap 21 between the control surface. So that the adhesive does not penetrate into this gap 21 and 6 ₇ pushes the control slide from the bottom 14, the spool is urged in the direction towards the bottom 14 of the housing 2 6 _7, which is represented by an arrow.

During operation of the applicator head, the spool 6 ₇ rotates about the axis of rotation A, so that when the spool 6 _{7 is} with its passage 15 ₇ in a sectional plane with the feed channel 4, adhesive from a connector not shown here connectable to the housing through the feed channel 4 and the passage 15 ₇ to the outlet opening 5 can be applied to a past the applicator head 1 medium. In this case, an outlet nozzle 18 may be attached to the outlet opening 5 of the housing 2 through which the adhesive passes. In the other rotational positions, the connection between the feed channel 4 and outlet opening 5 is interrupted by the control slide 6 ₇ , so that no adhesive is applied. As a result of the rotation of the control slide 6 ₇ , an adhesive seam is produced which arises from adhesive dots which adjoin one another. The length of the applied dots or beads can be varied by the rotational speed of the control slide 6 ₇ . For applications in which a continuous adhesive application is to be generated, the control slide 6 _{7 is brought} into a position in which the passage 15 ₇ in a sectional plane with the feed channel 4. The advantage of this embodiment is that the outlet opening 5 centrally on the axis of rotation A, which at the same time represents the symmetry axis of the applicator head, is arranged so that an accurate positioning and application of adhesive is made possible. In this case, the size of the applicator head, characterized in that a chamber is eliminated, kept small.

LIST OF REFERENCE NUMBERS

1

gun

2

casing

3

chamber

4

feed

5

outlet opening

6

spool

7

wave

9

cover

11

camp

12

circlip

13

pivot

14

ground

15

first passage

16

second passage

17

third passage

18

exhaust nozzle

19

seal

21

gap

22

print area

23

channel

24

output

25

poor

26

control surface

27

entrance

A

axis of rotation

α

arc section

Claims (6)

1. An application head for applying a liquid medium, for example hot-melt adhesive or cold glue, onto a substrate, comprising a housing (2) with a chamber (3) rotationally symmetrical with respect to an axis of rotation (A), a supply duct (4) into the chamber (3) and an outlet opening (5) - at the front - out of the chamber (3), as well as a control slide (6) which is mounted so as to be rotatable about the axis of rotation (A) and is capable of being driven in a rotating manner and which is situated at the front in the chamber (3) and bounds a free internal space in the chamber (3) and has at least one passage (15) for the through-flow of the liquid medium out of the chamber (3) into the outlet opening (5), characterized in that the control slide (6) has a plurality of passages (15, 16, 17) which extend over arcuate portions (α) of different size about the axis of rotation (A).
2. An application head according to Claim 1, characterized in that a plurality of passages (15) are provided which are at the same distance from the adjacent passage in each case.
3. An application head according to one of Claims 1 to 2, characterized in that the housing (2) comprises a cover (9) and a base (14), wherein a shaft (7) of the control slide (6) is mounted in the cover (9) and the control slide rests on the base (14).
4. An application head according to any one of Claims 1 to 3, characterized in that the control slide (6) has a control face (26) in the shape of a portion of a sphere which rests on a corresponding base (14) of the chamber (3) in the shape of a hollow sphere, or the control slide (6) has a tapered control face (26) which rests on a corresponding base (14) of the chamber (3) in the shape of a hollow taper, or the control slide (6) is formed in the shape of a disc and rests on the base (14) of the chamber (3).
5. An application head according to any one of Claims 1 to 4, characterized in that the at least one passage (15) is formed in the shape of a break-out at the edge open towards the outside.
6. An application head according to any one of Claims 1 to 6 [sic], characterized in that the control slide (6) has an internal duct (23) with an entry (27) and an exit (24) for the passage of compressed air, wherein the entry (27) is capable of being constantly acted upon with compressed air and the exit (24) is connected to the outlet opening (5) in one rotational position of the control slide (6).

Images