Apparatus and method for applying at least a two-component adhesive material to a workpiece

Abstract

The invention relates to a device for applying at least a two-component adhesive material to a workpiece, having a metering unit (12) with a number of metering valves (22) corresponding to the number of components of the adhesive material and having a static mixer (14) with a mixing tube (26) for mixing the components introduced into an inlet opening (28) on a first end of the mixing tube by means of the metering unit (12) as they pass from the inlet opening (28) to an outlet opening (30) on a second end of the mixing tube and having an outer tube (24), wherein the mixing tube (26) is accommodated in the outer tube (24) and is sealed against the environment at the inlet opening (28) and the outlet opening (30) respectively by means of a seal (48). According to the invention, the seals (48) each have an annularly encircling cutting edge (50) and the cutting edges (50) each cut into an end face (52) on the mixing tube (26) towards one another when a force is applied.

Description

Technical Field

[0001] The present invention relates to an apparatus for coating a workpiece with an adhesive material of at least two components. Background Technology

[0002] This equipment is particularly used in vehicle manufacturing and for creating viscous materials by mixing at least two components and applying them to workpieces. It is especially used when applying two-component adhesives. Another increasingly important application is the coating of fire-retardant materials onto battery casings of electric vehicles. Such fire-retardant materials are currently only available as at least two-component materials. Known equipment of this type includes a metering unit through which a number of feed channels, corresponding to the number of components in the viscous material, extend. Each feed channel is blockable and releaseable by a metering valve to allow for precise metering of each component. One of the components is meteredly introduced through each feed channel into a static mixer, where the components are mixed to form the viscous material. The static mixer has a mixing tube, which typically has a mixing spiral structure, and the mixing tube has an inlet at a first end and an outlet at a second end. The mixing tube is housed within a stable outer tube, which supports the mixing tube under high material pressure. A coating nozzle for discharging viscous material is connected to a discharge port, the coating nozzle having a coating opening from which the material is discharged.

[0003] This equipment has been successfully used for many years to coat two-component or multi-component materials onto workpieces. However, there have been occasional criticisms that in some applications, the viscous material can seep between the mixing tube and the outer tube, increasing the difficulty of replacing the mixing tube. Furthermore, there have been occasional criticisms that the start and / or end of the coating area for the viscous material cannot be defined sufficiently precisely in terms of shape and / or size. Summary of the Invention

[0004] Therefore, the objective of this invention is to improve the device of the type mentioned at the beginning in order to improve the sealing at the inlet and outlet.

[0005] This invention is based on the fundamental idea that the mixing tube used in such a device is only usable for a few hours before it becomes clogged by age-hardened material. The mixing tube must then be replaced, and the clogged material is removed. Therefore, this disposable item is typically made of plastic and cannot withstand high pressure. For this reason, the mixing tube is housed within a stable outer tube, preferably made of metal. In the presence of high material pressure, the outer tube supports the mixing tube, which, especially when the components are introduced under pressure, preferably rests its circumference against the inner surface of the outer tube along its entire length. The mixing tube is preferably loosely or detachably housed in the outer tube, allowing it to be removed from the outer tube and supplied to a cleaning device, while the outer tube can be reused. Advantageously, the mixing tube is inserted into the outer tube with a gap to allow for easy insertion and easy removal. Typically, the outer diameter of the mixing tube is a fraction of a millimeter smaller than the inner diameter of the outer tube. Thus, when the pressure inside the mixing tube rises to a few bar, for example, about 5 bar, the mixing tube elastically expands to rest its circumference against the inner surface of the outer tube. According to the invention, the problem of insufficient sealing, where viscous material or its components leak into the environment at the inlet or outlet and seep between the mixing tube and the outer tube, making the two tubes inseparable, is addressed by means of a surrounding cut edge. Therefore, the invention is based on the idea that the cut edges cut into the end faces of the mixing tube, typically made of soft plastic, and thus provide an excellent seal. Since the mixing tube is a disposable component, damage to it by the cut edge is inconsequential.

[0006] Advantageously, the first of the two cutting edges is connected to the metering unit, while the second of the two cutting edges is connected to the end component having a discharge channel. The end component may include a coating nozzle, a discharge valve, and other components if necessary. Furthermore, it is preferable that the metering unit and the end component are detachably connected to the outer tube via quick-release clips. The quick-release clips allow for the application of a large force, enabling the cutting edges to cut into the end face. Additionally, the quick-release clips allow for rapid disconnection if the mixing tube needs to be replaced.

[0007] According to an advantageous extension, the metering unit and the end component are detachably connected to each other by means of a connecting device. The connecting device suitably has a first connecting member connected to the metering unit and a second connecting member connected to the end component, wherein the first and second connecting members are longitudinally movable relative to each other by means of a guide device. This allows for better positioning of the components relative to each other, thereby pre-aligning the components when changing the mixer. Suitably, the guide device has an end stop that defines an end position of the end component relative to the metering unit, in which the cutting edge cuts into the end face of the mixing tube. Suitably, this end position is reached or nearly reached during quick clamping. This measure simplifies assembly because it ensures a sufficient seal is achieved by the cutting edge cutting into the end face of the mixing tube when the end component is located or near the end position relative to the metering unit. Advantageously, the guide device has an additional end stop that defines another end position of the end component relative to the metering unit, in which the cutting edges are positioned relative to each other at a distance greater than the mutual distance between the end faces of the mixing tube. Disconnecting the metering unit from the outer tube and the end component from the outer tube is thus possible, allowing the end component to move relative to the metering unit to the other end position while remaining connected to it and not having to be set aside, thereby further simplifying assembly.

[0008] According to an advantageous extension of the invention, each metering valve is equipped with a feed channel that can be blocked and released via an associated metering valve, the feed channel opening into a feed port, and the device has a coating nozzle connected to a discharge port with a coating opening for discharging viscous material, and a discharge valve for blocking and releasing the discharge channel extending from the discharge port to the coating opening. This extension is based on the idea that the discharge channel can be blocked by the discharge valve until sufficient pre-pressure of the viscous material is established in the discharge channel, enabling more precise material coating. Furthermore, by blocking the discharge channel with the discharge valve, material coating can be selectively terminated, and material residue will not be discharged from the coating opening in an undefined amount or shape. For this purpose, it is advantageous to provide a control device that operates the discharge valve to block and release the discharge channel. Suitably, a pressure sensor is provided for measuring the pressure of the viscous material in the discharge channel. Pressure measurement in the discharge channel allows for the selective establishment of a pre-pressure of the viscous material upstream of the discharge valve. Thus, the control device can operate the discharge valve based on the pressure measured by the pressure sensor. However, it is also possible that the control device operates the discharge valve based on the metering valve. Specifically, it can be specified that the discharge valve is opened to release the discharge channel only when the pressure measured by the pressure sensor reaches or exceeds a rated value. Alternatively or supplementarily, it can be specified that the control device operates the discharge valve to release the discharge channel after a predetermined time delay following the release of the supply channel through the metering valve. A particularly preferred method is one in which the discharge valve is opened at least a predefined time period after the metering valve is opened, but in principle, the discharge valve is only opened when a predetermined pre-pressure is measured in the discharge channel. To keep the pressure of the viscous material constant before the material coating is completed, it is preferable that the control device first operates the discharge valve to block the discharge channel and then operates the metering valve to block the supply channel, or simultaneously operates the discharge valve and the metering valve, at the end of the material coating process. Attached Figure Description

[0009] The invention will now be described in more detail with the aid of embodiments schematically illustrated in the accompanying drawings. The drawings are as follows:

[0010] Figure 1 A perspective view shows an apparatus for applying a two-component adhesive material to a workpiece;

[0011] Figures 2a to 2c The longitudinal section and detailed views W and X are shown according to Figure 1 The equipment;

[0012] Figure 3 Showing according to Figure 1 Detailed diagram of the equipment. Detailed Implementation

[0013] The apparatus 10 shown in the accompanying drawings is used to coat a two-component adhesive material onto a workpiece, particularly for coating a two-component fire-retardant material onto the battery casing of an electric vehicle. The apparatus includes a metering unit 12 and a static mixer 14 into which the two components are metered and pressurized. An end member 16 is connected to the static mixer, the end member having a coating nozzle 18 with a coating opening 20 from which the adhesive material is discharged and coated onto the workpiece.

[0014] The feed channels, not shown in more detail in the accompanying drawings, extend through the metering unit 12, providing one feed channel for each of the two components. The metering unit 12 also has two metering valves 22 configured as needle valves, each assigned to one of the feed channels and used to block or release that feed channel to allow the relevant component to pass through. The static mixer 14 has an outer tube 24 made of metal and a mixing tube 26 made of plastic housed within the outer tube 24. The mixing tube has an inlet 28 at its first end facing the metering unit 12, into which the feed channels open. The feed channels may open directly into the inlet 28 or merge into a central conveying channel before opening into the inlet 28. The mixing tube 26 has an outlet 30 at its second end, away from the first end and facing the end member 16, which opens into an outlet channel 32 extending through the end member 26 to the coating opening 20. To better mix these components into a viscous material, a mixing spiral structure 34 is provided inside the mixing tube 26. The mixing tube 26 is housed in the outer tube 24 with a very small gap, and once the internal pressure of the mixing tube reaches several bar, it expands elastically so that its circumference 36 abuts against the inner surface 38 of the outer tube 24 along its entire length, thereby supporting the mixing tube on the outer tube 24 so that it can also withstand the higher pressure of the material located in the mixing tube.

[0015] End component 16 has a discharge valve 40 configured as a needle valve for releasing or blocking the discharge channel 32. Furthermore, the end component has a substrate 42 connected to the static mixer 14, the substrate having a coating nozzle 18 and the discharge valve 40 mounted on the substrate. Additionally, end component 16 has a pressure sensor 44 for measuring the pressure of the viscous material present in the discharge channel 32. The pressure measurement value determined by the pressure sensor 44 is transmitted to a control device not shown in more detail in the accompanying drawings.

[0016] Metering unit 12 and end member 16 are connected to static mixer 14 via quick-release clips 46, enabling rapid replacement of static mixer 14. Once mixing tube 26 becomes blocked to an unacceptable degree by age-hardened or already age-hardened material, the two quick-release clips 46 are released, and static mixer 14 is replaced with a new static mixer. The blocked mixing tube 26 is then removed from outer tube 24 and cleared, while a new mixing tube is loaded into outer tube 24, thus creating a new static mixer. To prevent leakage of viscous material or its components into the environment at the transitions from metering unit 12 to static mixer 14 and from static mixer 14 to end member 16, seals 48 are provided there. These seals each have an annular surrounding cut edge 50, which is circular in plan view, with one cut edge 50 fixed to metering unit 12 and end member 16, respectively. The static mixer 14 is clamped between the metering unit 12 and the end member 16 by means of a quick-release clip 46, such that the cutting edge 50 cuts into the end face 52 of the mixing tube 26 when force is applied, and a good seal relative to the environment is achieved at the inlet 28 and the outlet 30.

[0017] Furthermore, the device 10 has a connecting device 54 that connects the metering unit 12 and the end member 16 to each other. The connecting device has a first connecting member 56 mounted on the metering unit 12 and a second connecting member 58 mounted on the end member 16. A connector 60 connected to the first connecting member 56 is used to mount the device 10 onto a robot arm. The connecting device 54 also has a guide device 62 that allows for limited movement of the first connecting member 56 and the second connecting member 58. The guide device 62 has an elongated hole 64 in the second connecting member 58 and an elongated protrusion 66 on the first connecting member 56 that is embedded in the elongated hole 64. The first end 68 of the protrusion facing the metering unit 12 abuts against the first end 70 of the elongated hole 64 facing thereto, defining an end stop. This end stop is characterized in that the cutting edges 50 are positioned at a distance less than the mutual distance between the end faces 52, such that the cutting edges cut into the end faces 52. The additional end stop is defined by the second end 72 of the protrusion 66 facing away from the metering unit 12 and the second end 74 of the elongated hole 64 facing it. If the first connecting member 56 and the second connecting member 58 are located in the positions defined by the additional end stop, the cutting edges 50 are set at a distance greater than the distance between the end faces 52, thereby canceling the sealing effect and allowing the static mixer 14 between the metering unit 12 and the end member 16 to be removed. The static mixer 14 can then be replaced without disconnecting the connection between the metering unit 12 and the end member 16. The metering unit and the end member are kept connected to each other by means of the connecting device 54.

[0018] To apply the viscous material to the workpiece, metering valve 22 is first opened, allowing the components to be metered and pressurized into the static mixer 14. A pre-pressure is typically established upstream of metering valve 22 before it is opened. Discharge valve 40 is opened only when sufficient pre-pressure has been established upstream of discharge valve 40 in discharge channel 32. This is typically a short time after metering valve 22 opens, allowing the control device to actuate discharge valve 40 to open after a time delay following the opening of metering valve 22. Furthermore, the pressure present in discharge channel 32 can be measured by means of pressure sensor 44. The measured pressure is then transmitted to the control device, which checks whether the measured pressure has at least reached a predetermined rated value. If so, discharge valve 40 opens at the predetermined time point after metering valve 22 opens. If not, discharge valve 40 remains closed until the pressure measured by pressure sensor 44 reaches the rated value. Alternatively, pressure sensor 44 can be omitted, and discharge valve 40 can open only after a predetermined time delay following metering valve 22. After the coating process is completed, the discharge valve 40 is closed, thus blocking the discharge channel 32. At the same time, or after a short delay, the metering valve 22 is closed, blocking the feed channel.

[0019] In summary, the invention relates to an apparatus 10 for coating a workpiece with at least two components of an adhesive material, comprising a metering unit 12 having a number of metering valves 22 corresponding to the number of components of the adhesive material; a static mixer 14 having a mixing tube 26 for mixing the components as they are guided through an inlet 28 at a first end of the mixing tube to an outlet 30 at a second end of the mixing tube, wherein each metering valve 22 is provided with a feed channel that can be blocked and released by the associated metering valve 22, and the feed channel leads into the inlet 28; and a coating nozzle 18 connected to the outlet 30, the coating nozzle having a coating opening 20 for discharging the adhesive material. According to the invention, a discharge valve 40 is provided for blocking and releasing the discharge channel 32 extending from the outlet 30 to the coating opening 20.

Claims

1. An apparatus for coating a workpiece with an adhesive material of at least two components, the apparatus having a metering unit (12) having a number of metering valves (22) corresponding to the number of components of the adhesive material, and the apparatus having a static mixer (14) having a mixing tube (26) and an outer tube (24), the mixing tube being used to mix the components introduced into a feed port (28) at a first end of the mixing tube by means of the metering unit (12) as they are guided through from the feed port (28) to an outlet (30) at a second end of the mixing tube, wherein, The mixing tube (26) is housed in the outer tube (24) and is sealed relative to the environment at the inlet (28) and outlet (30) respectively by means of a seal (48), characterized in that the seal (48) has an annular surrounding cut edge (50), and the cut edge (50) cuts into the end face (52) on the mixing tube (26) respectively when force is applied.

2. The device according to claim 1, characterized in that, The first of the two cutting edges (50) is connected to the metering unit (12), and the second of the two cutting edges (50) is connected to the end part (16) having the discharge channel (32).

3. The device according to claim 2, characterized in that, The metering unit (12) and the end component (16) are detachably connected to the outer tube (24) by means of a quick-release clip (46).

4. The device according to claim 2 or 3, characterized in that, The metering unit (12) and the end component (16) are detachably connected to each other by means of a connecting device (54).

5. The device according to claim 4, characterized in that, The connecting device (54) has a first connecting part (56) connected to the metering unit (12) and a second connecting part (58) connected to the end part (16), wherein the first connecting part (56) and the second connecting part (58) can move longitudinally relative to each other by means of a guide device (62).

6. The device according to claim 5, characterized in that, The guide device (62) has an end stop that defines the end position of the end component (16) relative to the metering unit (12), in which each cutting edge (50) cuts into the end face (52) on the mixing tube (26).

7. The device according to claim 6, characterized in that, The guide device (62) has an additional end stop that defines an additional end position of the end member (16) relative to the metering unit (12), in which the cut edges (50) are positioned relative to each other at a distance greater than the mutual distance of the end faces (52) on the mixing tube (26).

8. The device according to any one of claims 1 to 3, characterized in that, The mixing tube (26) is attached to the inner surface (38) of the outer tube (24) with the circumferential surface (36) of the mixing tube.

9. The device according to claim 8, characterized in that, When the components are introduced into the mixing tube (26) under pressure, the circumferential surface (36) of the mixing tube abuts against the inner surface (38) of the outer tube (24).

10. The device according to claim 8, characterized in that, The mixing tube (26) rests against the inner surface (38) of the outer tube (24) along its entire length with the circumferential surface (36) of the mixing tube.

11. The device according to any one of claims 1 to 3, characterized in that, The mixing tube (26) is loosely or detachably housed in the outer tube (24).

12. The device according to any one of claims 1 to 3, characterized in that, The outer tube (24) is made of metal.

13. The device according to any one of claims 1 to 3, characterized in that, Each metering valve (22) is equipped with a feed channel that can be blocked and released by the associated metering valve (22), each feed channel leading into the feed port (28), and the device has a coating nozzle (18) connected to the discharge port (30) and a discharge valve (40), the coating nozzle having a coating opening (20) for discharging viscous material, the discharge valve for blocking and releasing the discharge channel (32) extending from the discharge port (30) to the coating opening (20).

14. The device according to claim 13, characterized in that, A pressure sensor (44) is provided to measure the pressure of the viscous material in the discharge channel (32).

15. The device according to claim 14, characterized in that, A control device is provided for controlling the discharge valve (40) according to the operation of the metering valve (22) and / or according to the pressure measured by the pressure sensor (44).

16. A method for coating a workpiece with an adhesive material of at least two components, characterized in that, The method is used to coat a workpiece with at least two components of a viscous material by means of an apparatus (10) according to any one of claims 1 to 15, wherein each component is pressure-guided through a feed channel to a metering unit (12), the metering unit having a number of metering valves (22) corresponding to the number of components of the viscous material, the metering valves being used to release and block a corresponding one of the feed channels, wherein the components are meteredly introduced into the inlet (28) of the mixing tube (26) of a static mixer (14) by means of the metering unit (12), wherein the components are mixed into a viscous material in the static mixer (14), the viscous material being discharged from the outlet (30) of the mixing tube (26) into an outlet channel (32), the outlet channel extending to the coating opening (20) of a coating nozzle (18), and an outlet valve (40) for blocking and releasing the outlet channel (32) is operated by means of a control device.

17. The method according to claim 16, characterized in that, The pressure of the viscous material in the discharge channel (32) upstream of the discharge valve (40) is measured by a pressure sensor (44), the pressure measurement value is transmitted to the control device, and the control device operates the discharge valve (40) according to the pressure measurement value.

18. The method according to claim 17, characterized in that, The discharge valve (40) is opened to release the discharge channel (32) only when the pressure measured by the pressure sensor reaches or exceeds the rated value.

19. The method according to any one of claims 16 to 18, characterized in that, After the control device releases the feed channel through the metering valve (22), it operates the discharge valve (40) to release the discharge channel (32) with a predetermined time delay.

20. The method according to any one of claims 16 to 18, characterized in that, The control device first operates the discharge valve (40) to block the discharge channel when the material coating is finished, and then operates the metering valve (22) to block the supply channel, or operates the discharge valve (40) and the metering valve (22) simultaneously.

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