1. Field of the Invention
The invention relates to a strip coating device for continuous coating of strips, particularly metal strips, having at least one application head for applying liquid coating substances to a strip passing through the coating device. The application head has at least one application roller that applies the coating substance to the strip, and at least one supporting roller disposed on the side of the strip opposite the application head.
Within the scope of the invention, strips particularly means metal strips, for example steel strips or aluminum strips. Coating of such strips particularly means application of non-metallic, organic layers or coverings. In this regard, the application of liquid coating substances, for example varnishes or also plastics, is particularly involved. In addition to the application roller, the application head generally has at least one accommodation roller that accommodates the coating substance and gives it off to the application roller, directly or indirectly. If supply of the coating substance takes place by dipping the accommodation roller into a container, this roller is referred to as a scooping roller. If the application head merely consists of the accommodation roller and the application roller, one speaks of a two-roller head, and the accommodation roller then forms a metering roller, at the same time. However, within the scope of the invention, application head also means a so-called three-roller head, in which a metering roller or regulating roller is disposed between the accommodation roller and the application roller. Both two-roller heads and three-roller heads can be equipped to operate by rolling in the same direction or opposite directions.
2. The Prior Art
Strip coating devices are known in which the application head is disposed directly opposite the supporting roller, so that coating essentially takes place against the supporting roller. This has the advantage that the strip is perfectly supported during the coating process. However, in particular when coating thin strips, there is the problem that the coating substance is applied not only onto the strip to be coated, but also directly onto the supporting roller, since the application roller of the application head is generally wider than the strip to be coated, in order to assure a perfect coating process. Such contamination of the supporting roller, which is also called a “tambour,” is particularly undesirable if the position of the strip on the supporting roller changes as the strip passes through. Then an undesirable coating of the back of the strip can occur. The same thing applies in the case that varnish or the like runs onto the supporting roller.
It is therefore also known to provide the supporting roller with a mantle or stocking of rubber, for example, which has a width that is equal to the width of the strip to be coated. A disadvantage of this is the fact that the mantle must be replaced when the strip width changes, so the system must be stopped during the replacement.
Strip coating devices without a supporting roller are known, in which the application head works on a free strip region. The strip to be coated stands under strip tension in this region. It must always be noted that there are geometrical constraints for the strip guidance, because of the ovens that regularly follow the coating devices.
It is therefore an object of the invention to create a strip coating device of the type described above, which allows perfect coating and, at the same time, can be flexibly used for different purposes and, in particular, for different strip thicknesses.
This object is accomplished according to the invention by a strip coating device having an application head that works on the strip optionally either in a first functional position of the strip coating device, directly in the supporting region of the supporting roller, or, in a second functional position of the strip coating device, in a free strip region outside of the supporting region of the supporting roller. The coating device according to the invention has a combined structure, in which coating can take place in different functional positions of the device, either against a supporting roller or against a free strip under strip tension, with one and the same application head. With this, there is the possibility, for example, when using thick strips (thickness≧0.3 mm), to perform coating against the supporting roller, in known manner, since contamination of the supporting roller does not have to be feared if the strip thickness is sufficient, and use of the supporting roller allows perfect guidance of the strip. Then, after having switched the functional position to the second functional position, it is possible to coat thin strips (thickness<0.3 mm), for example, against the strip tension in a free strip region.
In this connection, it is practical if the supporting roller has at least one tensioning roller assigned to it on the side lying opposite the application head. This tensioning roller can precede or follow the supporting roller, in the strip running direction, by a predetermined distance. The application head, i.e. its application roller, then works on the strip either directly against the supporting roller, in the first functional position of the strip coating device, or, in the second functional position of the strip coating device, in the free strip region between the supporting roller and the tensioning roller. The tensioning roller can consequently have been put essentially out of function in the first functional position, while it assures the desired strip tension and perfect guidance of the strip in the second functional position, in interplay with the supporting roller and the application head.
Within the scope of the invention, the first functional position for coating preferably thick strips, the application roller of the application head and the supporting roller are disposed so that the distance between the surface of the application roller and the surface of the supporting roller approximately corresponds to the thickness of the strip to be coated. Consequently, the application roller rests directly against the supporting roller, with the interposition of the strip. Within the scope of the invention, thick strips means strips having a thickness of approximately 0.3 mm and more, for example. In contrast, in the second functional position, for coating thin strips, for example, the distance between the surface of the application roller and the surface of the supporting roller and/or the surface of the tensioning roller is greater than the thickness of the strip running through, by a predetermined dimension, in every case. It is practical if this distance, which is greater than the strip thickness, is selected to be relatively small, in order to achieve optimal guidance of the strip within the strip coating device. Within the scope of the invention, thin strips means strips having a thickness that is less than approximately 0.3 mm, for example. In this connection, the distance of the surface of the application roller from the surface of the supporting roller and/or the surface of the tensioning roller is less than 20 mm, preferably less than 10 mm, for example less than 5 mm, in the second functional position of the strip coating device. Thus, a distance of 1 mm to 5 mm can be particularly practical. Taking into consideration a strip thickness that cannot be ignored, the aforementioned distance is maximally 20 mm greater than the strip thickness, preferably maximally 10 mm greater than the strip thickness, for example maximally 5 mm greater than the strip thickness. In this regard, it can be practical if the distance is approximately 1 mm to 5 mm greater than the strip thickness.
According to a preferred embodiment of the invention, the strip is guided in the strip coating device in such a manner in the second functional position, that the looping angle of the strip around the application roller is less than 40°, preferably less than 30°, for example 10° to 20°. The looping angle depends on the radii of the rollers and the distance between the supporting roller and the tensioning roller, and on the “immersion depth” of the application roller into the region between the supporting roller and the tensioning roller.
According to a further embodiment of the invention, the supporting roller and the tensioning roller are disposed in or on a common roller frame. The position of the supporting roller and/or the position of the tensioning roller within the roller frame is adjustable, for a switch from one functional position into the other functional position.
In this connection, the tensioning roller and the supporting roller are mounted to rotate or are able to rotate each in a rotary frame, whereby the rotary frame itself is mounted to rotate within the roller frame. By arranging the tensioning roller and the supporting roller in a rotating rotary frame, the coating device can be quickly brought from the first functional position into the second functional position in a particularly simple manner, namely in that the rotary frame, with its rollers, is rotated by a corresponding angle of rotation. Complicated replacement of individual rollers is consequently not necessary. A greater change in position of the application head is also not required, since the change in functional position is primarily brought about by suitable positioning of the supporting roller and the tensioning roller, for example by the rotary frame. Nevertheless, it can be practical or necessary to also move the application head by a slight dimension, additionally to the adjustment to the functional position of the supporting roller and the tensioning roller. In this connection, the rotary frame has at least two rotary arms that connect the supporting roller and the tensioning roller with one another on their faces. The supporting roller and the tensioning roller are mounted on the rotary arms, on their ends, and the rotary frame can be rotated about a rotation axis disposed between the rotation axes of the rollers.
Preferably, one or more rotary drives are connected with the rotary frame, for example at one or both rotary arms. These allow an automated change in the functional positions. The rotary drives can be configured as linear drives, for example cylinder/piston arrangements, which are either connected directly with the rotary frame, for example with the rotary arms, or are connected by way of at least one transfer lever. The transfer lever can be configured as a crank or also as a turntable. The linear drives then engage eccentrically on such a crank or table. In any case, perfect translation of a linear drive movement into a rotary movement of the rotary frame, for the purpose of switching from one functional position to the other functional position, takes place in every case, by the use of a transfer lever. However, alternative drive concepts are also possible. Thus, for example, work can be carried out with electric motor drives that act on the shaft, with the interposition of gear mechanisms, in place of linear drives. Furthermore, there is the possibility of working with hydraulic pivot drives, for example.
The cylinder/piston arrangements that form the linear drives can be cylinder/piston arrangements that work hydraulically, pneumatically, or also electrically.
In a modified embodiment of the invention, at least the tensioning roller (and, if necessary, also the supporting roller) is mounted to rotate on a pivot frame. The tensioning roller can be pivoted with the pivot frame for the switch from one functional position into the other functional position. Such a pivot frame can have at least two pivot arms on which the tensioning roller is mounted, for example at the ends. Consequently, the supporting roller and the tensioning roller are not both moved within the roller frame with a rotary frame, but instead it can be sufficient to merely pivot the tensioning roller relative to the strip and/or to the supporting roller, in order to bring the coating device from the first functional position into the second functional position and vice versa. In the first functional position, with coating against the supporting roller, the tensioning roller is consequently pivoted out of the strip region. If, on the other hand, coating is supposed to take place against the strip under strip tension, the tensioning roller is pivoted towards the strip, while the supporting roller can fundamentally remain in its position. Preferably, however, the position of the supporting roller within the roller frame is also movable. For this purpose, the supporting roller can be displaceable, for example on linear guides, specifically also by way of suitable drives, namely displacement drives. Preferably, the tensioning roller is pivoted about a separate pivot axis of the pivot frame, which is at a distance from the rotary axis of the supporting roller. However, the pivot frame can also be connected with the supporting roller, so that the tensioning roller is pivoted about the supporting roller, i.e., the pivot axis of the pivot frame essentially coincides with the rotation axis of the supporting rollers.
It can be necessary to move the application head into the free strip region between supporting roller and tensioning roller, so that then coating can take place under strip tension, against the free strip between supporting roller and tensioning roller. With this embodiment, pivot drives are connected with the pivot frame, for example at the pivot arms. These pivot drives can also be configured as linear drives, for example cylinder/piston arrangements, which can be connected to the pivot arms directly or indirectly. In this connection, the pivot drives are connected with the free end of the pivot levers, lying opposite the tensioning roller, so that the pivot axis is disposed between tensioning roller or tensioning roller bearing and linkage of the pivot drives. In a modified embodiment, the pivot drives can engage on the pivot lever between the supporting roller and the tensioning roller.
The embodiments of the invention that have been described as preferred embodiments until now provide not only the supporting roller but also a tensioning roller, and the application head then performs application against the strip in a functional position between the supporting roller and tensioning roller. In a simplified embodiment, however, the tensioning roller can be eliminated, so that only the supporting roller and/or the application head must be moved to change the functional position, and the application head optionally works either against the supporting roller or against a free strip region next to the supporting roller.
The strip coating devices according to the invention are regularly a component of a strip coating system that usually consists of several strip coating devices. Several strip coating devices can be provided, in particular, for strip coating on the top, on the one hand, and on the bottom, on the other hand. In this connection, the embodiments that have been described can be combined with one another.
In total, the invention makes perfect strip coating possible with a strip coating device that is flexibly suited for completely different purposes. The same strip coating device can be optionally operated in different functional positions, which allow coating against the supporting roller, and coating against strip tension, i.e. against the free strip. This is possible, in a particularly simple manner, with the use of the rotary and/or pivot frames as described. The work can be carried out with minimal setting paths of the related application heads. This facilitates handling by operators working on the devices. Furthermore, the entire strip guidance within a continuous pass through a strip coating system is not influenced by the change in the functional positions, or only influenced slightly, so that strip guidance in the region of subsequent ovens, in particular, is not negatively influenced.
Other objects and features of the present invention will become apparent from the following detailed description considered in connection with the accompanying drawings. It is to be understood, however, that the drawings are designed as an illustration only and not as a definition of the limits of the invention.
In the drawings, wherein similar reference characters denote similar elements throughout the several views:
a shows an embodiment of a strip coating device according to the invention, in a first functional position;
b shows the strip coating device according to
a shows a modified embodiment of a strip coating device according to the invention, in a first functional position;
b shows the strip coating device according to
Referring now in detail to the drawings,
Each individual one of strip coating devices 1, 2, 3, 1′, 2′, 3′ has an application head 5 for applying liquid coating substances, for example varnishes, to the strip. Each application head 5 has at least one application roller 6, which applies the varnish to the strip. In the exemplary embodiment, application heads 5 are configured as three-roller heads, which have not only the actual application roller 6, but also an accommodation roller 7 and a metering roller 8 disposed between accommodation roller 7 and application roller 6. Accommodation roller 7 accommodates the coating substance and passes it to application roller 6 by way of metering roller 8. The structure of these known application heads is shown as an example in
Thus, there is the possibility, for example, of undertaking merely top coating with strip coating device 1, while application heads 5 of strip coating devices 2, 3 are moved out of the strip region. If, on the other hand, both top coating and bottom coating are supposed to take place, this can be done using application heads 5 of strip coating devices 2, 3, while application head 5 of strip coating device 1 is moved out of the strip region. The same holds true for the optional strip coating devices 1′, 2′, 3′.
Each of strip coating devices 1, 2, 1′, 2′ according to the invention has a supporting roller 9 on the side of strip M that lies opposite application head 5. In this embodiment, the strip to be coated loops around this roller by a predetermined looping angle. In this connection, supporting rollers 9, also called tambours, regularly have a greater diameter than application rollers 6. Application head 5 works on the strip optionally either in a first functional position of strip coating device 1, 2, directly in the supporting region of the supporting roller 9, or, in a second functional position of strip coating device 1, 2, in a free strip region outside of the supporting region of supporting roller 9. This is evident, for example, from a comparison of
a (and
Application head 5, i.e. its application roller 6, now no longer works against supporting roller 9, but rather against the strip tension, i.e., application roller 6 lies against the strip in a free strip region between supporting roller 9 and tensioning roller 10.
In this regard, the figures show that the distance a of the surface of application roller 6 from the surface of supporting roller 9 approximately corresponds to the thickness of the strip to be coated in the first functional position, for example for coating thick strips (thickness approximately ≧0.3 mm), so that application roller 6 lies (directly) against supporting roller 9, with the interposition of strip M (cf.
In contrast,
Furthermore,
According to the invention, supporting roller 9 and tensioning roller 10 are disposed in a common roller frame. The position of supporting roller 9 and/or tensioning roller 10 within this frame is adjustable, for a switch from one functional position into the other functional position. In this connection, the switch in functional position takes place primarily by a change in the position of the supporting roller and/or tensioning roller. Consequently, the application head merely has to be moved slightly for an adaptation to the functional position.
a and b as well as 3 to 6 show an embodiment of a coating device 2 according to the invention, in which tensioning roller 10 and supporting roller 9 are each mounted in a rotary frame 12 so as to rotate. Rotary frame 12 itself is mounted in roller frame 11. Coating device 2 is consequently brought from the first functional position into the second functional position, and vice versa, by rotating rotary frame 12. Rotary frame 12 has two rotary arms 13 that connect supporting roller 9 and tensioning roller 10 with one another at their faces.
The figures furthermore show that supporting roller 9 and tensioning roller 10 are each mounted on rotary arms 13 at their ends. The rotary frame, i.e. its rotary arms 13, can be rotated about a rotation axis 16 disposed between rotation axes 14, 15 of rollers 9, 10. A comparison of
In contrast,
Furthermore, it is indicated in
While
If, for example when coating thin strips, coating is to take place not against supporting roller 9, but rather against the free strip, then strip coating device 1 can be brought from the first functional position shown in
Accordingly, while only a few embodiments of the present invention have been shown and described, it is obvious that many changes and modifications may be made thereunto without departing from the spirit and scope of the invention.
Number | Date | Country | Kind |
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06000779 | Jan 2006 | EP | regional |
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221403 | Eyster | Nov 1879 | A |
1112812 | Labombarde | Oct 1914 | A |
4845964 | Bors et al. | Jul 1989 | A |
Number | Date | Country |
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196 21 993 | Dec 1996 | DE |
888 972 | Feb 1962 | GB |
Number | Date | Country | |
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20070163492 A1 | Jul 2007 | US |