EP2528696A1

EP2528696A1 - Electric application head for dispensing a free-flowing medium, and device comprising such an electric application head

Info

Publication number: EP2528696A1
Application number: EP11700852A
Authority: EP
Inventors: Hanspeter Felix; Roman Kappeler; Heinz Müller
Original assignee: Robatech AG
Current assignee: Robatech AG
Priority date: 2010-01-27
Filing date: 2011-01-25
Publication date: 2012-12-05
Also published as: EP2353731A1; EP2528695A1; ES2553142T3; CN102883821A; US20130026198A1; US9296008B2; EP2528695B1; US20140332569A1; BR112012018895A2; US20140054331A1; WO2011092164A1; WO2011092163A1; HK1179207A1; CN102821870B; DE202011000179U1; US20130026197A1; CN102821870A; BR112012018890A2

Abstract

The invention relates to an application head (15) for dispensing a free-flowing medium. The application head (15) comprises an injection chamber (10) inside the application head (15) and an injection needle (11) movably mounted inside the injection chamber (10). An opening movement (P) of the injection needle (11) opens an outlet (12). A supply channel (13) and a supply line are also provided in order to introduce the free-flowing medium into the injection chamber (10). A drive (20) generates the opening movement (P) of the injection needle (11). The application head (15) also comprises a lever arm (30), the first end (31) of said arm being movably fixed to a rear end (14) of the injection needle (11) and the second end (32) thereof being connected to the drive. A membrane suspension (33) comprising a membrane (34) is provided, and the lever arm (30) extends through the membrane (34) of the membrane suspension (33). The membrane suspension (33) is used to movably connect the lever arm (30) to the application head (15), and as a seal to prevent the free-flowing medium from leaking out.

Description

Electric applicator head for dispensing a flowable medium and device with such a Elektroauftragkopf

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. The invention can also be used for the controlled dispensing of cold glue or glue comprising aggressive (e.g., corrosive) components.

It claims the priority of European Patent Application EP 10 151 806.6, which was filed on 27.1.2010.

Background of the Invention, Prior Art

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

The corresponding guns must be robust and allow a precise, highly accurate delivery of the medium. At the same time, the application heads should be quickly switchable to portion or amount of adhesive to be able to apply with point or line precision. In addition, the guns should not be too big, as in the corresponding

Application devices often limited space is available.

If hot melt is to be processed, pose further problems. For example, the great heat inside a gun can

Drive unit damage. There are also types of glue that contain additives that can be aggressive. Thus, the pH of a glue may e.g. lie in the acidic area. Glue may also contain corrosive or abrasive ingredients. In order to protect a gun from it, appropriate measures must be taken.

It raises the task of a precise working and

To provide a reliable application head, which is part of the disadvantages

previously known solutions avoids or completely fixes.

The object is achieved by an applicator head according to claim 1 and by an applicator device according to claim 6.

A first applicator head according to the invention is specially designed for dispensing a flowable medium. It comprises a (nozzle) chamber inside the applicator head and a nozzle needle, a needle valve or a slider (collectively referred to herein as a "movable member") movably mounted inside the nozzle chamber and give each one for a short time

Outlet opening free. The applicator head can also act in reverse, in that the movable element closes 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 or

Closing movement of the movable element. There is a lever arm, whose first extremal end movably attached to a rear end of the movable member and whose second extremal end with the Drive is connected / coupled. Furthermore, the order header comprises a

Membrane suspension with a membrane. The lever arm extends in

Substantially perpendicular through a through the membrane of the

Membrane suspension spanned surface through. The membrane serves to connect the lever arm movably to the gun. Furthermore, the membrane suspension serves as a seal to prevent leakage of the flowable medium from the (nozzle) chamber. In addition, the membrane

preferably designed so that it is resistant to the flowable medium. Preferably, the membrane is at all

Embodiments temperature resistant and / or corrosion resistant and / or abrasion resistant and / or resistant to chemical additives in the medium.

Depending on the embodiment, the membrane may comprise at least one sealing ring which serves as a seal and for elastic clamping of the

Diaphragm in the application head is used. This embodiment can be used in all embodiments of the invention and provides a

improved seal z. B. against leaking adhesive.

Particularly preferred is an embodiment in which it is a metallic membrane, the particularly fast outward and

Can perform movements and thus allows a quick opening or 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 or closing is required. A metallic membrane is particularly advantageous and can be used in all embodiments of the invention.

The invention is particularly suitable for thermoplastic

(Hotmelt) adhesives. It is also suitable for aggressive types of glue and z. B. for cold glue.

In the subclaims are further advantageous

Embodiments of the invention listed. pictures

In the following, further details and advantages of the invention will be described in detail by means of embodiments and in part 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 is a schematic perspective view of a first

Embodiment of the invention;

Fig. 2 is a schematic sectional view of another

Embodiment of the invention;

Fig. 3A is a plan view of a membrane of another

Embodiment of the invention;

3B is a sectional perspective view of a diaphragm suspension of another embodiment of the invention;

Fig. 4 is an enlarged schematic sectional view of another

Embodiment of the invention;

Fig. 5 is a schematic side view of another

Embodiment of the invention;

6A is a sectional view of another embodiment of the

Invention in which a preferred thermally decoupled

To recognize connection between a drive and a gun;

6B is an enlarged sectional view of FIG. 6A.

Detailed description of the embodiments

In the following, the principle of the invention will be described with reference to a first embodiment. In Fig. 1 is an applicator 100 having a plurality of applicator heads 15 arranged in a row,

Nozzle outlet openings 12 and with individually switchable Adhesive supply lines 16 shown. Instead of the nozzle outlet openings 12 shown, other outlet openings 12 can also be used. The shape, arrangement and design of the outlet openings 12 may depend on whether a nozzle needle, a needle valve or a slider is used as a movable element 11 in the interior of the application head 15.

Each of the outlet openings 12 is on or in a respective one

Application head 15 is formed. Each applicator head 15 is specially designed for dispensing a flowable medium M, preferably of adhesive, and comprises a (nozzle) chamber 10 inside the applicator head 15. In the example shown, a nozzle needle 11 is in the interior of the (nozzle) chamber 10 and stored movable, wherein it releases the outlet opening 12 by an opening movement P of the nozzle needle 11. In Fig. 2, an arrow P is shown, which is directed upward. 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, four application heads 15 at the same time permanently emit a medium M in strip-like tracks (caterpillars). The strip shape is due to the passing z. B. a paper web K or a workpiece or a substrate. The corresponding direction of movement is V

characterized.

In the interior, a supply channel 13 is provided, which with the

(Nozzle) chamber 10 is connected. The supply channel 13 is connected to a

Supply line 16 fluidly connectable to bring the flowable medium M in the (nozzle) chamber 10 can. 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 application heads 15 or flanged. Preferably, the drive 20 includes its own drive 20 per applicator head 15 so that each exit opening 12 is opened and closed individually (i.e., independently of the others) can.

Particularly preferred are embodiments in which the drive 20 is spaced from the applicator head 15, e.g. to recognize in Fig. 2. However, it is important in the arrangement of the drive 20 with respect to the application head 15 (this statement applies to arrangements according to FIGS. 1 and 2) that the mutual distance is precisely defined and stable. This aspect is important because any distance change has an impact on the function or

Operation of the lever arm 30 may have. Details of the lever arm 3 are described below.

Further details will now be described with reference to another embodiment, which is shown 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 actuator 20 is spaced (i.e., spatially separated). The applicator 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 or other movable member and the second extremal 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, or the membrane suspension 33 has a dual function. In addition, it has, depending on the design of the membrane 34 a protective function against temperature, corrosion, abrasion and chemical additives of the

Medium M.

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 (also called needle seat) 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 top 18 of the Nozzle needle 11 is seated close to the attachment point 17 and no medium M can escape through the exit 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 movably connected to the lever arm 30 in the region of the rear end 14. As a result of the nozzle chamber 10 and the nozzle needle 11 being conically rotationally symmetrical in the lower region (near the attachment point 17), the nozzle needle 11 is guided centered in a downward movement M, which flows from the supply channel 13 through the (nozzle) chamber 11 in the direction of the outlet opening 12, to a

Stabilization, respectively self-centering of the nozzle needle 11 at. This type of "dangling" mounting or suspension can be used in all embodiments.

The lever arm 30 is here designed so that it comprises a flat, rectangular or strip-shaped rod, which is optionally provided with holes 39 here. These holes 39 serve to make the rod lighter in order to reduce the mass to be accelerated. In addition, the holes 39 allow a displacement of the starting point A of the drive 20. Thus, if the effective lever arm is to be extended, then the drive 20 (respectively

Starting point A) are moved further in the direction of the second extremal end 32 and vice versa. In the example shown, the drive 20 sits almost on

Extremal end 32, d .h. 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. With big

Lever arm takes place a reduction, ie. a big movement PI causes a small oppositely directed movement P. The

Reduction factor is shown in FIG. 2 about 5: 1 (ie the absolute value of the movement PI is about 5 times the absolute value of the movement P). With a small lever arm a translation takes place, ie a small movement PI causes a large oppositely directed movement P. However, the lever arm 30 may also have any other rod or lever shape. Preferably, the lever arm 30 is made of torsion-resistant material. In addition, the lever arm 30 should be as light as possible to have a small agitated mass. The membrane 34 is used in all embodiments as a kinematic bearing, which carries a portion of the mass of the lever arm 30 / stores. In addition, the membrane 34 defines in all embodiments the exact pivot point or tipping point (virtual

Called pivot axis) of the lever arm 30th

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 preferred arrangement are shown in FIG. This type of suspension can be at all

Embodiments are used

It can also be seen in FIGS. 2 and 4 that the membrane 34 can comprise one or two sealing rings 35, which make it possible to clamp the membrane 34 elastically in the application head 15. The

Sealing rings 35 are optional. For the purpose of clamping, the

Application head 15 a removable part or a lid (not shown in detail) include. When this part or lid is removed, the membrane 34 together with the optional sealing rings 35 can be inserted. Then, the said part or the lid is fixed again and the membrane 34 is clamped.

In Fig. 4 it can be seen that the rear of the membrane 34, d .h. on the side facing away from the (nozzle) chamber 10, an optional pressure support 38 is provided, which serves as a mechanical stop for the diaphragm 34. By this preferred embodiment is a

Overstretching of the diaphragm 34 at an overpressure in the nozzle chamber 10 prevented. The membrane 34 is preferably designed and arranged in all embodiments so that it is subjected to bending only, which is the Lifespan increased.

Preferably, in the various embodiments, a metallic membrane 34 is used, which is particularly suitable for alternating load with high frequency. Metallic membrane 34 is a membrane 34 in which either the entire membrane surface consists of a metal or in which a planar membrane substrate (for example made of plastic) is provided with a metal layer / metallization.

Furthermore, it can be seen in FIGS. 2 and 4 that a

Countermovement PI caused by the drive 20, a

opposite opening movement P of the nozzle needle 11 causes. The lever arm thus provides for a definition of the under or translation and for a reversal of motion.

Details of a preferred embodiment of a membrane 34 are shown in FIG. 3A. 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 position of the sealing ring (s) 35 is shown in FIG. 3A indicated. This design of the membrane 34 is particularly suitable for metallic membranes 34 to give the metallic membrane 34 the necessary elasticity.

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 (i.e., 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 one Part 41 of the

Diaphragms 34 virtually define a virtual pivot axis VA. This virtual pivot axis VA is shown in FIG. 3 represented by a dot-dash line.

Details of a preferred embodiment of a membrane suspension 33 are shown in FIG. 3B. Here is the attachment of the lever arm 30 at the membrane 34 can be seen. 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 shown in FIG. 3B indicated. The details shown in Fig. 3B can be applied to all

Apply 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 in an opening movement of

Nozzle needle 11 translated inside the applicator head 15. The drive 20 is here, as well as in Fig. 2, separately (i.e., spaced) from the applicator head 15.

As drive 20 is suitable in the various described

Embodiments

- electro-magnetic or

- pneumatic or

piezoelectric drive,

the corresponding frequency generates a corresponding linear movement PI (up and down movement), which passes through the effectively effective lever arm 30 a translation or translation to the nozzle needle 11 and there the

Linear motion P produces. In the case of a piezoelectric drive 20, one works here preferably with a translation in order to translate the very small movements of the piezoelectric drive 20 into sufficiently large opening and closing movements P.

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 particularly suitable for a 1: 1 lever translation or a reduction. A voice coil motor or a Lorentz coil can be used in all embodiments. The stroke in the region of the nozzle tip 18 or the outlet opening 12 is preferably between 0.1 mm and 1 mm. In a 1: 1 lever translation of the drive 20 must therefore make a correspondingly opposite movement PI with a stroke of 0.1 mm to 1 mm.

With a suitable drive of the drive 20, e.g. Via a driver module 21, which can be arranged in the vicinity of the drive 20, as indicated by way of example in FIG. 5, the movement behavior of the nozzle needle 11 or of another movable element 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 life of the nozzle needle 11 and the applicator head 15. A corresponding driver module 21 can at all

Embodiments are used.

The larger the lever ratio is selected, the more accurate the nozzle needle 11 can move, because a large movement PI of the drive 20 is translated into a small movement P of the nozzle needle 11. A disadvantage of such a large translation but is the extended route, the

must be covered 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 drive (e.g., in the form of the driver module 21) of the drive 20 is designed to observe the current being fed to the drive 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 data stored in the driver module 21 can be made

Movement profile can be made, which compensates for a wear of the needle tip 18 in that the movement PI is gradually increased on the drive side, when the current signal indicates that the current increase compared to earlier occurs later. 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 intelligent control (eg in the form of the driver module 21) increases the

Life of the application head 15, since the nozzle needle 11 only later

must be replaced.

In a preferred embodiment, on the drive side, an intelligent drive (for example in the form of the driver module 21) of the drive 20 is 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 directly with a 24 VDC signal (also directly from a PLC) can be controlled (PLC stands for

Programmable logic controller). This has the advantage that everyone

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, for example, Fig. 5) between drive 20 and the part of

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 achieved without screw, as shown in FIG. 6A and the

Section 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 distance / positioning bolts 46. The fixing of the application head 15 and drive 20 via two ropes 47th

(preferably steel cables). Preferably, a non-heat conducting cable 47 is used. The ropes 47 are fixed in the application head 15 at the points XI and are tensioned in the drive 20 by a tensioning device 48. By this arrangement, the applicator head 15 and the drive 20 are ideally secured by no metallic connection (only two thin cables 47 in the present arrangement).

The lever arm 30, in all preferred embodiments, reverses the direction of travel (PI points in the opposite direction as P, see Fig. 2) and, depending on the adjustment of the lever arm lengths, one

Motion gain (P> PI) or motion reduction (PI> P). In addition, the angular arrangement of the lever arm 30 with respect to the movable member 11 allows the diaphragm 34 to be located in a region which is not directly exposed to the flowing medium M.

LIST OF REFERENCE NUMBERS

(Nozzle) Chamber 10 movable member (e.g., nozzle needle) 11

Outlet opening 12

Supply channel 13 rear end of the nozzle needle 11 14

Application head 15

Supply line 16

Lifting point 17

Tip 18

Drive 20

Driver module 21

Lever arm 30 first extremal end 31 second extremal end 32nd

Membrane suspension 33

Diaphragm 34

Sealing ring 35

Slits 36

Central opening 37

Pressure support 38

Holes 39 cylindrical rod 40 inner part of the diaphragm 34 41

Footbridges 42

Caps 43

Insulation plate 44

Positioning bolt 45

Distance- / Potitionierbolzen 46

Ropes 47

Clamping device 48

Application device 100

Starting point A

Paper web K flowable medium M

Direction of movement V

Virtual axis VA

Opening movement P

Countermovement PI

Points XI

Claims

claims:

1. application head (15) for dispensing a flowable medium (M), with

a chamber (10) inside the applicator head (15),

- a movable element (11) inside the chamber (10)

is movably mounted, wherein it by a movement (P) of the nozzle needle (11) an outlet opening (12) releases or closes,

- A supply channel (13) which is connected to the chamber (10) and with a supply line (16) fluidly connectable to bring the flowable medium (M) in the chamber (10) can,

a drive (20) for generating the opening movement (P) of the

movable element (11),

characterized in that the applicator head (15) comprises:

- A lever arm (30), whose first extreme end (31) movable

a rear end (14) of the movable element (11) is fixed 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) through the membrane (34) of the

Membrane suspension (33) extends through,

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 chamber (10).

Second application head (15) according to claim 1, characterized in that the

Membrane suspension (33) in addition to the membrane (34) comprises at least one sealing ring (35) which serves as a seal and the elastic

Clamping the membrane (34) in the applicator head (15) is used.

3. application head (15) according to claim 1 or 2, characterized in that it is the membrane (34) is a metallic membrane (34).

4. application head (15) according to claim 1, 2 or 3, characterized 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 head (15) according to claim 1, 2, 3 or 4, characterized in that the arrangement of the lever arm (30), the movable element (11) and the diaphragm suspension (33) with the diaphragm (34) is chosen such that the Movement (P) of the nozzle needle (11) is opposite to a

Movement (PI) on the second extremal end (32) of the lever arm (30).

Application device (100) for dispensing a flowable medium (M), with

a supply line (16) for flowable medium (M),

- An application head (15) with internal chamber (10),

- a movable element (11) inside the chamber (10)

is movably mounted, wherein it releases or closes an outlet opening (12) by a movement (P) of the movable element (11),

- A supply channel (13) which is fluidically connected to the chamber (10) and the supply line (16) in order to bring the flowable medium (M) in the chamber (10) can,

- A drive (20) for generating the movement (P) of the movable

Elements (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 movable member (11) and its second extreme end (32) connected to the drive (20) is

- A membrane suspension (33) in or on the applicator head (15) with a membrane (34), wherein

o the lever arm (30) through the membrane (34) of the

Membrane suspension (33) extends through,

o the membrane suspension (33) serves as a seal to escape the flowable medium (M) from the chamber (10) to prevent.

7. Application device (100) according to claim 6, characterized in that the membrane suspension (33) in addition to the membrane (34) comprises at least one sealing ring (35) serving as a seal and for elastically clamping the membrane (34) in the application head ( 15) is used.

8. application device (100) according to claim 6 or 7, characterized

characterized in that the membrane (34) is a metallic membrane (34).

9. application device (100) according to claim 6, 7 or 8, characterized

characterized in that the membrane (34)

- Identifies slots (36) to increase the elasticity, and

10. application device (100) according to claim 6, 7, 8 or 9, characterized

in that the application head (15) has a pressure support (38) on the side of the diaphragm (34) which faces away from the chamber (10).

11. Application device (100) according to one of the preceding claims 6 to

10, characterized in that a

- electro-magnetic or

- pneumatic or

- Piezoelectric drive

serves as a drive (20).

12. Application device (100) according to one of the preceding claims 6 to

11, characterized in that the application head (15) and the drive (20) are thermally decoupled.

13. Application device (100) according to one of the preceding claims 6 to 12, characterized in that the arrangement of the lever arm (30), the movable member (11) and the diaphragm suspension (33) with the diaphragm (34) is selected so that the movement (P) of the nozzle needle (11) is opposite to a movement (PI) on the second extrema end (32) of the lever arm (30).