DE102018119838A1 - Device for applying an at least two-component viscous material to workpieces - Google Patents

Abstract

The invention relates to a device (10) for applying an at least two-component viscous material to workpieces with a metering unit (12), which has a number of metering valves (18) corresponding to the number of components of the viscous material and a coupling device (20), and with a static mixer (14), which has a mixing tube (28) for mixing the components when passing through a material inlet (30) at its first end to a material outlet (32) at its second end, and a coupling section that is detachably fixed to the coupling device (20) 26), the metering valves (18) opening into the material inlet (30). According to the invention, the coupling device (20) has a plurality of engagement elements (52) for engaging in recesses (50) on the coupling part (26) which are open at the edge, as well as an actuating element (56) which can be moved from a locking position into a release position by means of pressurization by a fluid in the locking position holds the engagement elements (52) for fixing the coupling part (26) on the coupling device (20) in the open-edge recesses (50) and releases them in the release position to release the fixing.

Description

The invention relates to a device for applying an at least two-component viscous material to workpieces according to the preamble of claim 1.

Such devices are used, for example, in the manufacture of motor vehicles in order to apply multicomponent materials, such as, for example, two-component adhesives, to body components. They have a metering unit which has a number of metering valves corresponding to the number of components of the viscous material and a coupling device, each metering valve being connected to a feed line for one of the components in order to meter the respective component to a static mixer. The static mixer has a coupling section with which it is detachably fixed to the coupling device of the metering unit, and a mixing tube into which the components are introduced by the metering valves. The components are mixed as they are passed through from a material inlet at the first end of the mixing tube to a material outlet at the second end, in particular by being passed through a mixing spiral arranged in the mixing tube. The static mixer is a wearing part that clogs up over time due to hardening residues of the viscous material and has to be replaced or cleaned from time to time. A static mixer is replaced by hand by detaching the coupling section from the coupling device and attaching a new static mixer to the metering unit. Known devices have a bayonet connection as coupling means for the connection between the coupling device and the coupling part. The loosening of the bayonet connection by hand is perceived as complex, since a fitter must always be available when a static mixer has to be replaced.

It is therefore an object of the invention to develop a device of the type mentioned in the introduction in such a way that the replacement of the static mixer is simplified.

This object is achieved according to the invention by a device with the features of claim 1 and by a method with the features of claim 18. Advantageous developments of the invention are the subject of the dependent claims.

The invention is based on the idea of automatically replacing the static mixer without a mechanic having to intervene. For this purpose, the coupling device of the metering unit has an actuating element which can be moved from a locking position into a release position by means of pressurization by a fluid such as compressed air. The movement from the release position into the locking position expediently takes place in that the actuating element is forced into the locking position by the force of at least one elastic restoring element, so that it is held there by means of the force of the restoring element unless it is pressurized by the fluid. The coupling device also has a plurality of engagement elements, while the coupling section of the static mixer has a corresponding number of recesses which are open at the edge and into which the engagement elements can engage. The engaging elements are held by the actuating element in the open-edged recesses when it is in the locking position, so that the coupling part is fixed to the coupling device. In the release position of the actuating element, the engagement elements are released to release the fixation. It is thus possible, by pressurizing the actuating element, to decouple a static mixer which is no longer functional from the metering unit, to place the metering unit on a new static mixer and to fix it with its coupling part to the coupling device of the metering unit by reducing the pressure acting on the actuating element.

The automatic change of the static mixer can be designed particularly advantageously if the device has a receiving device for static mixer. Such a receiving device, which can also be referred to as a change station, serves to accommodate structurally identical static mixers, each of which has a mixing tube for mixing the components of the viscous material when passing through from the material inlet at the first end to the material outlet at the second end, and a coupling section which can be detachably fixed to the coupling device exhibit. The receiving device has a plate, which can also be referred to as a table, which has a plurality of receiving openings which are open at the edge, holding means for holding one of the static mixers being arranged in each receiving opening. To change the static mixer, which is no longer functional, the dosing unit with the static mixer fixed to it is moved to the receiving device by means of a robot, and the static mixer is inserted laterally over the open edge into one of the receiving openings and held there by means of the holding means. The actuating element is then moved into the release position by pressurizing the fluid, so that the fixing of the coupling part to the coupling device is released. The dosing unit is then lifted from the static mixer by the robot and onto another one, in another receiving opening of the receiving device mounted static mixer. By reducing the pressurization, the actuating element is moved back into the locking position, so that the coupling part of the further static mixer is fixed on the coupling device. Finally, the dosing unit with the further static mixer fixed to it is moved by the robot through the open edge out of the receiving opening away from the receiving device and can be used again for applying viscous material.

In particular, the change of the static mixer can be initiated automatically by means of a control unit if a measured parameter of the device deviates from a predetermined target value by more than a predetermined tolerance value. The characteristic variable can be, for example, the pressure in the static mixer, which is measured by means of a pressure sensor and then rises above a tolerable value when the static mixer has partially clogged with hardened material.

It is preferred that the coupling section engages in the coupling device and that the open-edged recesses are open to an outer lateral surface of the coupling section. This ensures a stable connection between the dosing unit and the static mixer. In addition, it can advantageously be provided that the open-edged recesses are connected to one another to form a circumferential annular groove, the annular groove expediently having a constant cross section over its entire length. This facilitates the positioning of the dosing unit with respect to the static mixer when it is coupled to the dosing unit. The metering unit can then be placed on the static mixer rotated as desired about a longitudinal central axis of the mixing tube, if the engagement elements can engage at any point in the annular groove forming the open-edge recesses.

It is possible for the actuating element to be formed in several pieces, with each of the pieces acting on one of the engaging elements in the locking position. A simpler construction is achieved, however, if the sections of the actuating element which act on one of the engaging elements in the locking position are rigidly connected to one another and can be moved together into the locking position and back into the release position.

The coupling device expediently has a housing in which the actuating element can be moved between the locking position and the release position, this movement advantageously being linear. It is further preferred that the housing has a pressure space delimited on one side by the actuating element and means for introducing and discharging the fluid into and out of the pressure space. The actuating element then acts like a piston which is pressurized by the fluid, preferably compressed air. The housing expediently has a bottom wall delimiting the pressure space on the side facing away from the actuating element, in which at least one opening is closed by a removable closure element. If, for example in the event of a failure of a compressed air compressor, no fluid is available to act on the actuating element, intervention can be made through the opening (s) in order to move the actuating element into the release position. It is further preferred that the engaging elements are mounted in the housing. They are expediently designed as balls which are easy to produce and, moreover, can be moved without great effort, since they have a smooth surface over which the actuating element can slide and because they can be rotated about any axes of rotation.

Preferably, the engagement elements can be moved towards one another in the radial direction when they are actuated by actuating surfaces on the actuating element when it is moved into the locking position. They then narrow the cross section of the coupling device in the area of the open-edged recesses or in the area of the circumferential annular groove. Furthermore, it is preferred that the actuating element has retreat spaces for receiving the engaging elements in the release position. The engaging elements can withdraw into the retreat spaces if they are to be displaced from the open-ended recesses or from the annular groove forming the open-edge recesses in order to remove the fixation of the static mixer on the metering unit. In order to facilitate movement of the engagement elements into the open-edged recesses when the actuating element moves into the locking position, it is advantageously provided that the actuating element in each case connects an actuating surface with a retraction space and an angle of more than 180 ° and less than 270 with the respective actuating surface ° has inclined run-up slopes, so that the engagement elements are continuously advanced during the movement of the actuating element from the release position into the locking position.

The coupling part is expediently detachably connected to the mixing tube. When the mixing tube is clogged with material and must either be thrown away or cleaned, the coupling section can be detached from the mixing tube and attached to a new mixing tube and thus used again.

Different types of mixing tubes can be used with the device according to the invention. It is possible that the mixing tube is rigid and made of metal. A mixing helix, likewise made of metal, is expediently inserted in such a mixing tube. Such mixing tubes are generally cleaned, if they are clogged by hardened material, by removing the mixing helix and cleaning the components individually using cleaning fluid. Usually, however, the mixing tube has an inner tube made of plastic which has the material inlet and the material outlet and a support tube made of metal which receives the inner tube at least over most of its length. A mixing helix is then usually arranged in the inner tube, which is also expediently made of plastic. If the mixing tube with hardened material is clogged, the inner tube is removed from the supporting tube and thrown away, while the supporting tube can be used again by inserting a new inner tube. The inner surface of the support tube lies against the outer lateral surface of the inner tube and prevents the inner tube from expanding under pressure. In addition, the support tube defines the location of the material outlet since, in contrast to the inner tube made of plastic, it is not or only slightly flexible.

For positioning in the receiving device described above or in the change station, the static mixer advantageously has two centering disks which protrude radially from the mixing tube and are spaced apart in the axial direction. The static mixers are then inserted into the change station in such a way that a first centering disc is arranged above and a second centering disc below the plate. The upper centering disc prevents the static mixer from moving downwards when the robot places the dosing unit on the coupling section. The lower centering disc prevents the static mixer from being pulled up out of the plate if the dosing unit lifts off the coupling section after moving the actuating element into the release position of the robot.

• 1a, 1 b eine Auftragsvorrichtung für zweikomponentiges viskoses Material in einer Teildarstellung im Schnitt mit an einer Dosiereinheit fixiertem Statikmischer sowie mit von der Dosiereinheit losgelöstem Statikmischer;
• 2a, 2b den Statikmischer gemäß 1a, 1b teilweise zerlegt in perspektivischer Ansicht sowie im Schnitt und
• 3 eine Aufnahmeeinrichtung für Statikmischer.

The invention is explained in more detail below on the basis of an exemplary embodiment shown schematically in the drawing. Show it

• 1a . 1 b an application device for two-component viscous material in a partial representation in section with a static mixer fixed to a dosing unit and with a static mixer detached from the dosing unit;
• 2a . 2 B according to the static mixer 1a . 1b partly disassembled in perspective view and in section and
• 3 a receiving device for static mixers.

The in the drawing ( 1a . 1b) partially shown device 10 is used to apply a two-component adhesive to workpieces. It has a doiser unit 12 as well as a static mixer 14 on, which is moved relative to the workpieces by means of a robot, not shown, during the application process. The dosing unit 12 has one in 1 a . 1 b valve block shown only partially 16 with two metering valves 18 on, which are designed as needle valves. Furthermore, the dosing unit 12 a coupling device 20 on that releasably and firmly with the valve block 16 is connected, and in the valve seats 22 are arranged. The valve needles 24 extend into the coupling device 20 and open and close the metering valves 18 on the valve seats 22 ,

The static mixer 14 has a coupling section 26 on that in the coupling device 20 intervenes ( 1a) and is releasably attached to it. The static mixer 14 also has a mixing tube 28 on that is from a material inlet 30 at its first end to a material outlet 32 extends at its second end. The mixing tube is at the material inlet 30 expanded and communicates there with the metering valves 18 , At the material outlet 32 it is conically narrowed. It has a material inlet 30 and the material outlet 32 having inner tube 34 made of plastic in which a mixing spiral 36 is arranged. It also has a support tube 38 made of metal that spans most of the length of the inner tube 34 extends and on its outer surface 40 is applied. When the two-component adhesive is applied, the two components (base component and hardener) are each applied using one of the metering valves 18 dosed into the material inlet 30 delivered and initially through a partition 42 separated the mixing helix 36 fed. In the mixing spiral 36 the two components mix on their way to the material outlet 32 , The clutch section 26 is part of an adapter 44 that is detachable with the support tube 38 is connected and for this purpose an internal thread 46 for screwing onto an external thread on the support tube 38 having.

For fixing to the coupling device 20 has the coupling section 26 a circumferential ring groove 50 which has a constant cross-section over the entire circumference. In the coupling device 20 are metal balls 52 captive, which is used to engage the ring groove 50 represent certain engaging elements to the coupling section 26 in the coupling device 20 to fix. The ring groove 50 thus forms a continuous succession of open recesses 50 in the outer surface 54 the coupling section 26 , For loading the balls 52 has the coupling device 20 an annular actuator 56 on that in a case 58 the coupling device 20 between a locking position ( 1a) and a release position ( 1b) is linearly displaceable. The actuator 56 has operating areas 60 on in the locked position according to 1a apply the balls and they towards a longitudinal central axis 62 of the static mixer 14 in the ring groove 50 press and hold there to the clutch section 26 on the coupling device 20 to fix. The actuator 56 also has a retreat area for each ball 64 in which the respective ball 50 from the longitudinal central axis 62 can retract away when the actuator 56 according to 1b is in the release position. Between the retreat rooms 64 , which in turn can be connected all around, and the actuating surfaces 60 is a ramp 66 arranged on the when moving the actuator 56 the respective ball from the release position to the locking position 50 can slide, and that with the associated actuating surface 60 encloses an angle of approx. 225 °. For moving the actuating element 56 points the case 58 a pressure room 68 on the top through the actuator 56 is limited, which acts like a piston. In the pressure room 68 Compressed air can be introduced via a compressed air connection, which is the actuating element 56 against the force of against the housing 58 supported compression springs 70 from the locking position according to 1a in the release position according to 1b raising. The compression springs 70 push the actuator 56 depressurized and hold it in the locked position. To the static mixer 14 to be detached from the dosing unit when compressed air is not available are in the bottom of the housing 58 by screws 72 openings closed as closure elements 74 arranged by removing the screws 72 for example, can be reached with pins to the actuator 56 against the force of the compression springs 70 to raise.

The static mixer 14 must be replaced regularly with a new static mixer when there is in the mixing tube 28 cured remnants of the viscous material. This manifests itself regularly in a significant pressure increase in the mixing tube 28 during the material application. Such an increase in pressure can be detected with suitable sensors, and an automatic change of the static mixer can then be carried out by means of a control unit 14 be performed. For this purpose there is a receiving device 76 intended ( 3 ) which is a plate 78 which is like a table top on a stand 80 rests. The plate 78 has four open openings 82 on, in each of which holding means 84 for static mixers 14 are arranged. In 3 is shown as in three receiving openings 82 one static mixer each 14 according to 2a . 2 B is recorded while the fourth opening 82 is empty. If the control unit detects that on the dosing unit 12 fixed static mixer 14 needs to be replaced, the dosing unit 12 with the static mixer 14 from robot to pick-up device 76 moves and the mixing tube 28 is in the radial direction in the free receiving opening 82 introduced, the material outlet 32 down and the coupling section 26 points upwards. The mixing tube 28 snaps between the holding means 84 that prevent it from falling out through the open edge. Each of the static mixers 14 also has a lower and an upper centering disc 86 . 88 on, spaced from each other radially from the mixing tube 28 protrude. The static mixer 14 always in the reception facility 76 arranged that the lower centering disc 86 under the plate 78 is arranged while the upper centering disc 88 over the plate 78 is arranged. The actuator 56 is then automatically pressurized with compressed air and moves to the release position, so that the static mixer is fixed 14 on the dosing unit 12 will be annulled. The dosing unit 12 can then from the robot from the static mixer 14 be lifted off, the lower centering disc 86 the static mixer 14 in the reception facility 26 stops when the dosing unit 12 is pulled upwards.

The robot then moves the dosing unit 12 to one of the others, in the receiving device 76 supported static mixer 14 and sets the clutch device 20 on its coupling section 26 on, with the upper centering disc 88 of the further static mixer 14 prevents this from coming down from the cradle 76 is pushed out. Then the compressed air is removed from the pressure chamber 68 drained so that the compression springs 70 the actuator 56 move into the locked position and the other static mixer 14 on the dosing unit 12 is fixed. The dosing unit 12 with the additional static mixer attached to it 14 is then moved out of the further static mixer 14 from the open edge of the plate 78 by means of the robot from the receiving device 76 removed and used for further application of two-component adhesive.

In summary, the following can be stated: The invention relates to a device 10 for applying at least two-component viscous material to workpieces with a dosing unit 12 which is a number of metering valves corresponding to the number of components of the viscous material 18 and a coupling device 20 has, and with a static mixer 14 which is a mixing tube 28 for mixing the components when passing through a material inlet 30 at its first end to a material outlet 32 at its second end and a detachable on the coupling device 20 fixed coupling section 26 has, wherein the metering valves 18 into the material inlet 30 lead. According to the invention, it is provided that the coupling device 20 several engagement elements 52 for engaging in open-edged recesses 50 on the coupling section 26 and an actuating element which can be moved by means of pressurization by a fluid from a locking position into a release position 56 has the engaging elements in the locking position 52 to fix the coupling part 26 on the coupling device 20 in the open recesses 50 holds and releases them in the release position to release the fixation.

Claims (19)

Device for applying an at least two-component viscous material to workpieces with a metering unit (12), which has a number of metering valves (18) corresponding to the number of components of the viscous material and a coupling device (20), and with a static mixer (14), the has a mixing tube (28) for mixing the components when passing through a material inlet (30) at its first end to a material outlet (32) at its second end and a coupling part (26) detachably fixed to the coupling device (20), the metering valves (18) open into the material inlet (30), characterized in that the coupling device (20) has a plurality of engagement elements (52) for engaging in recesses (50) on the coupling part (26) which are open at the edge, and one from a locking position by means of pressurization by a fluid a release position movable actuator (56) which in the locking position d he engaging elements (52) for fixing the coupling part (26) on the coupling device (20) in the open-edge recesses (50) and releases them in the release position to release the fixation. Device after Claim 1 , characterized in that the coupling part (26) engages in the coupling device (20) and in that the open-edge recesses (50) are open to an outer lateral surface (54) of the coupling part (26). Device after Claim 1 or 2 , characterized in that the open-edged recesses (50) are interconnected to form a circumferential annular groove. Device after Claim 3 , characterized in that the annular groove has a constant cross section over its entire length. Device according to one of the preceding claims, characterized in that the actuating element (56) is pushed into the locking position by the force of at least one elastic return element (70). Device according to one of the preceding claims, characterized in that the actuating element (56) has a plurality of rigidly connected sections, each of which acts on one of the engaging elements (52) in the locking position. Device according to one of the preceding claims, characterized in that the coupling device (20) has a housing (58) in which the actuating element (56) is preferably linearly movable between the locking position and the release position. Device after Claim 7 , characterized in that the housing (58) has a pressure space (68) delimited on one side by the actuating element (56) and means for introducing and discharging the fluid into and out of the pressure space (68). Device after Claim 8 characterized in that the housing (58) has a bottom wall delimiting the pressure chamber (68) on the side facing away from the actuating element (56), in which at least one opening (74) closed by a removable closure element (72) is arranged. Device according to one of the Claims 7 to 9 , characterized in that the engagement elements (52) are mounted in the housing (58) and are preferably designed as balls. Device according to one of the preceding claims, characterized in that the engagement elements (52) can be moved towards one another in the radial direction when acted upon by means of actuating surfaces (60) on the actuating element (56) when it is moved into the locking position. Device according to one of the preceding claims, characterized in that the actuating element (56) has retraction spaces (64) for receiving the engaging elements (52) in the release position. Device after Claim 12 , characterized in that the actuating element (56) each has an actuating surface (60) connecting a retraction space (64), with the respective actuating surface (60) enclosing an incline of more than 180 ° and less than 270 ° incline (66). Device according to one of the preceding claims, characterized in that the coupling part (26) is detachably connected to the mixing tube (28). Device according to one of the preceding claims, characterized in that the mixing tube (28) has an inner tube (34) made of plastic and has the material inlet (30) and the material outlet (32) and a support tube which receives the inner tube (34) at least over most of its length (38) made of metal. Device according to one of the preceding claims, characterized in that the static mixer (14) has two centering disks (86, 88) which project radially from the mixing tube (28) and are spaced apart in the axial direction. Device according to one of the preceding claims, characterized by a receiving device (76) for static mixers (14), each having a mixing tube (28) for mixing the components of the viscous material when passing through a material inlet (30) at its first end to a material outlet ( 32) at its second end and a coupling part (26) which can be detachably fixed to the coupling device (20), with a plate (78) which has a plurality of receiving openings (82) which are open at the edge, with holding means (84) in each receiving opening (82) Holding one of the static mixers (14) are arranged. Method for changing a static mixer (14) according to a device (10) Claim 17 , wherein the metering unit (12) with the static mixer (14) fixed to it is moved by a robot to the receiving device (76), the static mixer (14) being inserted laterally over the open edge into one of the receiving openings (82) and by means of the holding means (84) is held there, the actuating element (56) being moved into the release position by the application of pressure by means of the fluid, the metering unit (12) being lifted from the static mixer (14) by means of the robot and onto another one in the receiving device (76) supported static mixer (14) is placed, the actuating element (56) being moved into the locking position by reducing the pressurization to fix the coupling section (26) of the further static mixer (14) on the coupling device (20), and wherein the metering unit (12) with the further static mixer (14) fixed to it by means of the robot while moving the further static mixer (14) out through de n open edge is moved out of the receiving opening (82) away from the receiving device (76). Procedure according to Claim 18 , characterized in that a control unit automatically initiates the change of the static mixer (14) if a measured parameter of the device deviates from a predetermined target value by more than a predetermined tolerance value.

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