EP2353731A1 - Electric application head for dispensing a flowable medium and device with such an electric application head - Google Patents

Abstract

The suspension (33) has a lever arm (30) connected with a moving element (11) and a drive (20) so as to convert drive-sided motion (P1) into opening movement (P) of the moving element. A metallic membrane (34) is effectively connected with the lever arm. The suspension movably connects the lever arm with an adhesive application head (15) and serves as a sealing to prevent discharge of adhesive from a chamber (10). A sealing ring (35) flexibly clamps the membrane at the adhesive application head. The membrane comprises a slot. An independent claim is also included for an adhesive application head for discharging flowing adhesive.

Description

The invention relates to an applicator head for dispensing a flowable medium and an applicator device with at least one such applicator head. In particular, it concerns the dispensing of adhesives and the use of hot glue.

Background of the Invention, Prior Art

In numerous industrial machining processes adhesives, sealants and similar flowable media are used, which are applied or sprayed onto a workpiece in liquid form.

The corresponding application heads must be robust and allow a precise, highly accurate delivery of the medium. At the same time, the application heads should be able to be switched quickly in order to be able to portion portions of adhesive or to apply spot or line precision. In addition, the guns should not be too large, since there is often limited space available in the respective applicators.

If hot melt is to be processed, pose further problems. For example, the high heat inside an applicator head can damage the drive unit.

It has as its object to provide a precisely working and reliable applicator head, which avoids or completely eliminates some of the disadvantages of previously known solutions.

The object is achieved by an applicator head according to claim 1 and by an applicator device according to claim 5.

A first application head according to the invention is specially designed for dispensing a flowable medium. It comprises a nozzle chamber in the interior of the application head and a nozzle needle which is movably mounted in the interior of the nozzle chamber. The nozzle needle performs an opening movement and releases an outlet opening for a short time. There is a supply channel which is connected to the nozzle chamber and fluidly connectable to a supply line. Through the supply line and the supply channel, the flowable medium can be introduced into the nozzle chamber. A drive generates the opening movement of the nozzle needle. There is a lever arm, the first extremal end of which is movably attached to a rear end of the nozzle needle and whose second extremal end is connected to the drive. Furthermore, the applicator head comprises a membrane suspension with a membrane. The lever arm extends through the membrane suspension membrane which serves to movably connect the lever arm to the applicator head. Furthermore, the membrane suspension serves as a seal to prevent leakage of the flowable medium from the nozzle chamber.

Depending on the embodiment, the membrane may comprise at least one sealing ring, which serves as a seal and for elastic clamping of the membrane in the applicator head. This embodiment provides an improved seal, for example against leaking adhesive.

Particularly preferred is an embodiment in which it is a metallic membrane that can perform particularly fast back and forth movements and thus allows a quick opening and closing of the outlet opening. Such a metallic membrane is particularly suitable for high frequency alternating load, i. for embodiments in which a very fast opening and closing is required.

The invention is particularly suitable for thermoplastic (hotmelt) adhesives.

In the subclaims further advantageous embodiments of the invention are listed.

pictures

Fig. 1

eine schematische Perspektivansicht einer ersten Ausführungsform der Erfindung;

Fig. 2

eine schematische Schnittansicht einer weiteren Ausführungsform der Erfindung;

Fig. 3A

eine Draufsicht einer Membrane einer weiteren Ausführungsform der Erfindung;

Fig. 3B

eine perspektivische Schnittansicht einer Membranaufhängung einer weiteren Ausführungsform der Erfindung;

Fig. 4

eine vergrößerte schematische Schnittansicht einer weiteren Ausführungsform der Erfindung;

Fig. 5

eine schematische Seitenansicht einer weiteren Ausführungsform der Erfindung;

Fig. 6A

eine Schnittdarstellung einer weiteren Ausführungsform der Erfindung, in der eine bevorzugte thermisch-entkoppelte Verbindung zwischen einem Antrieb und einem Auftragskopf zu erkennen ist;

Fig. 6B

eine vergrösserte Schnittdarstellung der Fig. 6A.

In the following, further details and advantages of the invention will be described in detail by means of embodiments and partly with reference to the drawing. All figures are schematic and not to scale, and corresponding structural elements are given the same reference numerals in the different figures, even if they are designed differently in detail. Show it:

Fig. 1

a schematic perspective view of a first embodiment of the invention;

Fig. 2

a schematic sectional view of another embodiment of the invention;

Fig. 3A

a plan view of a membrane of another embodiment of the invention;

Fig. 3B

a sectional perspective view of a membrane suspension of another embodiment of the invention;

Fig. 4

an enlarged schematic sectional view of another embodiment of the invention;

Fig. 5

a schematic side view of another embodiment of the invention;

Fig. 6A

a sectional view of another embodiment of the invention, in which a preferred thermally decoupled connection between a drive and a gun is to recognize;

Fig. 6B

an enlarged sectional view of the Fig. 6A ,

Detailed description of the embodiments

The principle of the invention will be described below with reference to a first embodiment. In Fig. 1 For example, an applicator 100 having a plurality of applicator heads 15, nozzle outlets 12, and individually switchable adhesive supply lines 16 is shown.

Each of the exit openings 12 is formed on or in a respective application head 15. Each applicator head 15 is designed especially for dispensing a flowable medium M, preferably of adhesive, and comprises a nozzle chamber 10 in the interior of the applicator head 15. A nozzle needle 11 is mounted in the interior of the nozzle chamber 10 movable up and down, wherein they by an opening movement P of Nozzle needle 11, the outlet opening 12 releases. in the Fig. 2 an arrow P is shown pointing upwards. An opening movement in the direction of the arrow raises the nozzle needle 11 and this releases the outlet openings 12, so that the medium M can escape from the nozzle chamber 10 through the outlet openings 12. In Fig. 1 At the same time, four application heads 15 simultaneously permanently emit a medium M in strip-like tracks (caterpillars). The strip shape arises due to the passing of, for example, a paper web K. The corresponding direction of movement is marked V.

Inside, a supply channel 13 is provided, which is connected to the nozzle chamber 10. The supply channel 13 can be fluidically connected to a supply line 16 in order to be able to introduce the flowable medium M into the nozzle chamber 10. In Fig. 1 four separate supply lines 16 are indicated. But it can also be a common Supply line 16 for a plurality of application heads 15 are used.

Furthermore, a drive 20 for generating the opening movement P of the nozzle needle 11 is provided. In Fig. 1 the drive 20 is attached to the applicator heads 15 or flanged. Preferably, the drive 20 includes its own drive 20 per applicator head 15, so that each outlet opening 12 can be opened and closed individually (ie independently of the others).

Further details will now be given by way of another embodiment, which is in Fig. 2 is shown in a section explained. In Fig. 2 a section through a single applicator head 15 is shown, in which the drive 20 spaced (ie, spatially separated) is arranged. The application head 15 according to the invention comprises per drive 20 a lever arm 30, the first extreme end 31 is movably attached to a rear end 14 of the nozzle needle 11 and the second extreme end 32 is connected to the drive 20. A membrane suspension 33 with a membrane 34 is used, with the lever arm 30 extending through the membrane 34 of the membrane suspension 33. The membrane suspension 33 serves to connect the lever arm 30 movably with the applicator head 15. In addition, the membrane suspension 33 serves as a seal to prevent leakage of the flowable medium M from the nozzle chamber 10. That is, the membrane 34, respectively the membrane suspension 33 has a dual function.

The following further details characterize this embodiment. The nozzle chamber 10 is designed so that in its lower region near the outlet opening 12, a stop point 17, respectively, a stop surface for the tip 18 of the nozzle needle 11 is provided. In Fig. 2 the nozzle needle 11 is shown in the closed position, ie the tip 18 of the nozzle needle 11 is seated close to the attachment point 17 and it can no medium M escape through the outlet opening 12. As soon as the nozzle needle 11 is lifted by the opening movement P, the outlet opening 12 is released and medium M can emerge.

The nozzle needle 11 is movable in the region of the rear end 14 connected to the lever arm 30. The nozzle needle 11 "dangles" quasi in the nozzle chamber 10. Because the nozzle chamber 10 in the lower region (near the attachment point 17) is conically rotationally symmetrical, the nozzle needle 11 is guided centered in a downward movement. In addition, the medium M, which flows from the supply channel 13 through the nozzle chamber 11 in the direction of the outlet opening 12, contributes to a stabilization or self-centering of the nozzle needle 11.

The lever arm 30 is here designed so that it comprises a flat, rectangular or strip-shaped rod, which is provided here with holes 39. These holes 39 serve to make the rod lighter in order to reduce the mass to be accelerated. In addition, the holes 39 allow the starting point A of the drive 20 to be displaced. Thus, if the effective lever arm is to be extended, the drive 20 (or the starting point A) can be moved further in the direction of the second extreme end 32 and vice versa. In the example shown, the drive 20 sits almost at the extreme end 32, i. the effective lever arm is relatively large. The closer the drive 20 (or the starting point A) in the direction of the diaphragm suspension 33 is displaced, the shorter the effective lever arm.

In order to store or hold the lever arm 30 in the membrane suspension 33, a cylindrical rod 40 is provided on the lever arm 30 in the embodiment shown. This cylindrical rod 40 clamps or clamps the diaphragm 34 and thus provides a suspension of the lever arm 30 on the diaphragm 34. Details of an exemplary arrangement are the Fig. 4 refer to.

In the Figures 2 and 4 It will also be appreciated that the diaphragm 34 may include one or two seal rings 35 which allow the diaphragm 34 to be resiliently clamped in the applicator head 15. For the purpose of clamping, the applicator head 15 may comprise a removable part or lid (not shown in detail). If this part or this cover is removed, the membrane 34 can be inserted together with the sealing rings 35. Then the said part or lid is re-attached and the membrane 34 is clamped.

In Fig. 4 It can be seen that an optional pressure support 38, which serves as a mechanical stop for the diaphragm 34, is provided at the rear of the diaphragm 34, ie on the side which faces away from the nozzle chamber 10. By this preferred embodiment, an overstretching of the diaphragm 34 is prevented at an overpressure in the nozzle chamber 10. The diaphragm 34 is preferably designed and arranged so that it is stressed only on bending, which increases the service life.

Preferably, in the various embodiments, a metallic diaphragm 34 is used, which is particularly suitable for high-frequency alternating load.

Furthermore, in Figures 2 and 4 to recognize that a counter-movement P1, which is caused by the drive 20, causes an opposite opening movement P of the nozzle needle 11.

In Fig. 3A Details of an embodiment of a membrane 34 are shown. The membrane 34 includes slots 36 to increase the elasticity. In addition, a central opening 37 is provided through which the lever arm 30 extends in the assembled state. The location of the sealing ring (s) 35 is in Fig. 3A indicated.

Due to the special arrangement of the slots 36, which define almost a complete circle, two small webs 42 result at the position 3 o'clock and 9 o'clock. These two small webs 42 allow bending of the inner part 41 (ie, that circular portion 41 of the diaphragm 34 which is radially outwardly delimited by the slots 36) of the diaphragm 34. The two small webs 42 with the inner part 41 of FIG Diaphragms 34 virtually define a virtual pivot axis VA. This virtual pivot axis VA is in Fig. 3 represented by a dot-dashed line.

In Fig. 3B are details of one embodiment of a Membrane suspension 33 shown. Here, the attachment of the lever arm 30 can be seen on the diaphragm 34. This attachment is made by the rod 40 as described. In the embodiment shown, the rod 40 is hollow inside to reduce the weight. So that no medium M can escape through the interior of the rod 40, the rod 40 can have caps 43 or sealing elements at both ends, for example. The position of the virtual pivot axis VA is also in Fig. 3B indicated. In the Fig. 3B Details shown apply to all embodiments.

Fig. 5 shows details of another embodiment of the invention. The arrangement of the elements is different here, but the function is the same. A linear movement of the drive 20 is translated into an opening movement of the nozzle needle 11 in the interior of the application head 15.

• elektro-magnetischer oder
• pneumatischer oder
• piezo-elektrischer Antrieb,

der mit der gewünschten Frequenz eine entsprechende Linearbewegung P1 (Auf- und Abbewegung) erzeugt, die durch den effektiv wirksamen Hebelarm 30 eine Unter- oder Übersetzung an die Düsennadel 11 weitergibt und dort die Linearbewegung P hervor ruft.As drive 20 is suitable in the various described embodiments

• electro-magnetic or
• pneumatic or
• piezoelectric drive,

the generated with the desired frequency a corresponding linear movement P1 (up and down movement), which passes through the effectively effective lever arm 30, a lower or translation to the nozzle needle 11 and there the linear movement P produces.

Has proven particularly useful an electro-magnetic drive 20, which is constructed according to the principle of a voice coil motor or a Lorentz coil. As an effective translation is especially a 1: 1 1 translation. A voice coil motor or a Lorentz coil can be used in all embodiments.

The stroke in the region of the nozzle tip 18 is preferably between 0.1 mm and 1 mm. With a 1: 1 ratio, the drive 20 must therefore make a correspondingly opposite movement P1 with a stroke of 0.1 mm to 1 mm.

In a suitable control of the drive 20, for example via a driver module 21, which may be arranged in the vicinity of the drive 20, as in Fig. 5 indicated by way of example, the movement behavior of the nozzle needle 11 can be adjusted or even regulated. If desired, a suitable movement profile can be deposited, so that the nozzle needle 11 is decelerated just before it hits the attachment point 17. This measure increases the service life of the nozzle needle 11 and of the application head 15. A corresponding driver module 21 can be used in all embodiments.

The larger the ratio is chosen, the more accurate the nozzle needle 11 can move, because a large movement P1 of the drive 20 is translated into a small movement P of the nozzle needle 11. However, a disadvantage of such a large ratio is the extended distance that has to be traveled on the drive side. This reduces the achievable frequency, respectively, the maximum clock of the opening and closing movement of the nozzle needle eleventh

In a preferred embodiment, on the drive side, an intelligent driver (e.g., in the form of the driver module 21) of the drive 20 is designed to monitor the current being fed to the driver 20. If the current increases, then this is an indication that the nozzle needle 11 is present at the stop point 17. By means of an intelligent control, a creeping adaptation of the motion profile stored in the driver module 21 can be undertaken, which compensates for a wear of the needle tip 18 by successively increasing the movement P1 on the drive side if the current signal indicates that the current increase occurs later than in the past , The later occurrence of a current increase means namely that the needle tip 18 is present later than at the stop point 17. This is a sign of wear. The use of such an intelligent drive (for example in the form of the driver module 21) increases the service life of the application head 15, since the nozzle needle 11 has to be replaced later.

In a preferred embodiment, on the drive side a intelligent control (eg in the form of the driver module 21) of the drive 20 designed so that the movement of the nozzle needle 11 is regulated according to a predetermined movement profile. The switching times and the stroke of the nozzle needle 11 can be monitored and the application image of the application head 15 can be automatically corrected by this control.

Preferably, the driver module 21 is located directly on each drive 20 so that the drive 20 can be controlled directly with a 24 VDC signal (also directly from a PLC). This has the advantage that each application head 15 can be controlled individually. A corresponding driver module 21 can be used in all embodiments.

In a preferred embodiment, an intelligent control of the drive 20 is designed on the drive side so that error, warnings, service or maintenance displays are issued. This approach can be used in all embodiments.

It is an advantage of the invention that a spatial thermal separation (see eg Fig. 5 ) between the drive 20 and the part of the application head 15 is possible, which is flowed through by the medium M. Especially with warm or hot medium M thereby reduce the problems that can be caused on the drive side otherwise by the high temperature.

Preferably, the thermal separation between the drive 20 and gun 15 is solved without screw, as in Fig. 6A and the detail enlargement 6B can be seen.
On the application head 15, an insulation plate 44 is placed. The isolation plate 44 is formed on the gun side with two positioning bolts 45 and on the drive side with four spacer / positioning bolts 46. The fixing of the application head 15 and drive 20 via two ropes 47 (preferably steel cables). Vorzusgweise a non-heat conducting cable 47 is used. The ropes 47 are fixed in the application head 15 at the points X1 and are tensioned in the drive 20 by a tensioning device 48. Through this Arrangement, the applicator head 15 and the drive 20 are ideally fastened via no metallic connection (in the present arrangement only by two thin cables 47).

LIST OF REFERENCE NUMBERS

nozzle chamber

10

nozzle needle

11

outlet opening

12

supply channel

13

rear end of the nozzle needle 11

14

gun

15

supply line

16

anchorage point

17

top

18

drive

20

driver module

21

lever arm

30

first extreme end

31

second extremal end

32

membrane suspension

33

membrane

34

seal

35

slots

36

central opening

37

pressure support

38

holes

39

cylindrical rod

40

inner part of the membrane 34

41

Stege

42

cut

43

insulation plate

44

positioning bolts

45

Distance / Potitionierbolzen

46

ropes

47

jig

48

applicator

100

starting point

A

paper web

K

flowable medium

M

movement direction

V

Virtual axis

VA

opening movement

P

countermovement

P1

Points

X1

Claims (11)

Application head (15) for dispensing a flowable medium (M), with a nozzle chamber (10) inside the applicator head (15), - A nozzle needle (11) which is movably mounted in the interior of the nozzle chamber (10), wherein it by an opening movement (P) of the nozzle needle (11) releases an outlet opening (12), - A supply channel (13) which is connected to the nozzle chamber (10) and with a supply line (16) fluidly connectable to bring the flowable medium (M) in the nozzle chamber (10), a drive (20) for generating the opening movement (P) of the nozzle needle (11), characterized in that the applicator head (15) comprises: - A lever arm (30) whose first extreme end (31) is movably attached to a rear end (14) of the nozzle needle (11) and whose second extreme end (32) is connected to the drive (20), - A membrane suspension (33) with a membrane (34), wherein o the lever arm (30) extends through the membrane (34) of the membrane suspension (33), o the membrane suspension (33) serves to connect the lever arm (30) movably with the applicator head (15), and o The membrane suspension (33) serves as a seal to prevent leakage of the flowable medium (M) from the nozzle chamber (10). Applicator head (15) according to claim 1, characterized in that the membrane suspension (33) in addition to the diaphragm (34) comprises at least one sealing ring (35) serving as a seal and for elastically clamping the diaphragm (34) in the applicator head (15). serves. Applicator head (15) according to claim 1 or 2, characterized in that the membrane (34) is a metallic membrane (34). Applicator head (15) according to claim 1, 2 or 3, characterized in that the membrane (34) - Identifies slots (36) to increase the elasticity, and - Has a central opening (37) through which passes the lever arm (30) in the mounted state. Application device (100) for dispensing a flowable medium (M), with a supply line (16) for flowable medium (M), - An applicator head (15) with internal nozzle chamber (10), - A nozzle needle (11) which is movably mounted in the interior of the nozzle chamber (10), wherein it by an opening movement (P) of the nozzle needle (11) releases an outlet opening (12), - A supply channel (13) which is fluidically connected to the nozzle chamber (10) and the supply line (16) in order to introduce the flowable medium (M) in the nozzle chamber (10), a drive (20) for generating the opening movement (P) of the nozzle needle (11), characterized in that the applicator (100) comprises: - A lever arm (30), the first extreme end (31) in the interior of the applicator head (15) is movably attached to a rear end (14) of the nozzle needle (11) and its second extremal end (32) to the drive (20) is connected . - A membrane suspension (33) in or on the applicator head (15) with a membrane (34), wherein o the lever arm (30) extends through the membrane (34) of the membrane suspension (33), o the membrane suspension (33) serves to connect the lever arm (30) movably with the applicator head (15), and o The membrane suspension (33) serves as a seal to prevent leakage of the flowable medium (M) from the nozzle chamber (10). Applicator device (100) according to claim 5, characterized in that the membrane suspension (33) in addition to the diaphragm (34) comprises at least one sealing ring (35) serving as a seal and for elastically clamping the diaphragm (34) in the applicator head (15). serves. Applicator device (100) according to claim 5 or 6, characterized in that the membrane (34) is a metallic membrane (34). Applicator (100) according to claim 5, 6 or 7, characterized in that the membrane (34) - Identifies slots (36) to increase the elasticity, and - Has a central opening (37) through which passes the lever arm (30) in the mounted state. Applicator device (100) according to claim 5, 6, 7 or 8, characterized in that the applicator head (15) has a pressure support (38) on that side of the diaphragm (34) which faces away from the pressure chamber (10). Applicator device (100) according to one of the preceding claims 5 to 9, characterized in that a - electro-magnetic or - pneumatic or - Piezoelectric drive serves as a drive (20). Applicator (100) according to one of the preceding claims 5 to 10, characterized in that the applicator head (15) and the drive (20) are thermally decoupled.

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