WEB-TENSION-MEASURING DEVICE, USE OF SUCH AND A ROLLER COMPRISING A WEB-TENSION-MEASURING DEVICE

Abstract

A web-tension-measuring device has two plates, which can be rotated relative to one another about an axis of rotation, to be precise such that the one free end of the one plate can be moved towards, or away from, the corresponding, opposite free end of the other plate. A force transducer is arranged in the region of the free ends of the two plates and outside the axis of rotation. The force transducer is configured, during movement of the free ends of the two plates towards one another, to detect a corresponding compressive loading arising from the movement and, during the movement of the free ends away from one another, to detect a corresponding tensile loading between the two plates.

Claims

1-14. (canceled)

15. A web tension measuring device, comprising: two plates disposed to be rotated relative to one another about an axis of rotation, to thereby move one free end of one of said plates toward, or away from, a corresponding, opposite free end of another of said plates; a force transducer disposed in a region of the free ends of said two plates and distally from the axis of rotation; said force transducer being configured, during a movement of the free ends of said two plates towards one another, to detect a compressive loading corresponding to the movement and, during a movement of the free ends away from one another, to detect a corresponding tensile loading between said two plates.

16. The web tension measuring device according to claim 15, further comprising a rotary joint coupling said the two plates to one another, enabling said two plates to be rotated relative to one another about the axis of rotation.

17. The web tension measuring device according to claim 15, wherein said plates are arranged at a spacing distance from one another.

18. The web tension measuring device according to claim 17, wherein said plates are arranged one above the other.

19. The web tension measuring device according to claim 15, wherein said two plates are two separate plates.

20. The web tension measuring device according to claim 15, wherein said force transducer is arranged between said two plates.

21. The web tension measuring device according to claim 15, wherein said force transducer has a first axial end connected to the free end of a first one of said plates, and a second axial end connected to the free end of a second one of said plates, opposite said first one of said plates, to thereby load the force transducer in shear under a corresponding tensile loading or compressive loading.

22. The web tension measuring device according to claim 15, wherein each of the free ends of said two plates is provided with a single said force transducer.

23. The web tension measuring device according to claim 15, wherein said force transducer is a shear sensor configured for picking up shear loadings.

24. A roll, comprising: a shaft rotatably mounted for rotation about a roll axis, said shaft having axial ends rotatably mounted in a bearing arrangement; wherein the roll has an outer circumference for wrapping a web over at least a part thereof; and a web tension measuring device according to claim 15 assigned to at least one said bearing arrangement of said shaft.

25. The roll according to claim 24, configured for a machine for producing or treating fibrous material webs selected from the group consisting of paper, board, and tissue paper.

26. The roll according to claim 24, wherein said bearing arrangement comprises a bearing housing and said web tension measuring device is indirectly or directly connected to said housing.

27. The roll according to claim 24, wherein the axis of rotation of said web tension measuring device extends parallel to and at a distance from the roll axis of the roll.

28. The roll according to claim 24, wherein the force transducer and the axis of rotation of said web tension measuring device lie in a plane which extends at right angles to a plane through the roll axis.

29. The roll according to claim 28, wherein the axis of rotation lies outside and at a spacing distance from the plane through the roll axis.

30. A method of measuring a web tension of a web wrapping at least partly around an outer circumference of a roll, the method comprising: rotatably supporting axial ends of a shaft of the roll for rotation about a roll axis in a bearing arrangement; wrapping the web over a part of an outer circumference of the roll; and providing a web tension measuring device according to claim 15 assigned to at least one bearing arrangement of the shaft and measuring the web tension of the web while rotating the roll.

31. The method according to claim 30, wherein the web is a fibrous material web or a clothing.

32. The method according to claim 31, wherein the web is a fibrous material web selected from the group consisting of a paper web, a board, and a tissue web.

33. The method according to claim 31, wherein the web is a clothing selected from the group consisting of a forming fabric, a dryer fabric, and a press felt.

Description

[0013] Further advantageous expressions of the invention will be explained by using exemplary embodiments and with reference to the drawings. The aforementioned features can advantageously be implemented not only in the combination illustrated but also combined individually with one another. The single FIG. 1 shows a possible embodiment of such a web tension measuring device according to the invention in a side view which is schematic and therefore not to scale in the direction of the axis of rotation D of the web tension measuring device 1.

[0014] As can be gathered from FIG. 1, the web tension measuring device 1 can be used indirectly to detect the web tension F.sub.z of a web F transported by a roll 6. Such a roll 6 comprises a shaft 7 that can be rotated about a roll axis W. The web F always wraps around part of the outer circumference of said roll. The roll 6 can therefore be a driven roll, then called a guide roll, or a co-rotating roll, then called a deflection roll. In any case, the roll 6 has a bearing arrangement 8 at its two axial ends, in order to dissipate the axial and/or radial forces of the latter to a frame of the machine, for example.

[0015] For the indirect detection of the web tension F.sub.z, at least one (or both) bearing arrangement(s) 8 has a bearing housing 8.1, to which the web tension measuring device 1 is connected. From the reaction forces acting on the bearing housing 8.1, it is then possible to draw conclusions about the actually present web tension F.

[0016] To detect these reaction forces, the web tension measuring device 1 has two plates 2, 3 which, in the present case, are arranged at a distance from each other, here, by way of example, parallel to each other. At their one end, both plates 2, 3 here can be pivoted at an angle about the axis of rotation D relative to each other. This pivoting (or rotation) can be achieved, for example, by means of a rotary joint 5, via which the two plates 2, 3 are connected to each other. Thus, the free ends 2.1, 3.1 of the plates 2, 3 can then be moved toward each other and away from each other.

[0017] In order to permit such a movement, the plates are preferably designed separately from each other, which therefore means not designed in one piece with each other in the region of the free ends 2.1, 3.1. In principle, it would be conceivable to connect the two plates 2, 3 by means of a third plate (not illustrated). This could taper between the two plates 2, 3 and therefore form an axis of rotation under loading, around which the two plates 2, 3 could then pivot relative to each other.

[0018] Also arranged in the region of the free ends 2.1, 3.1 of the plates 2, 3 is a force transducer 4. According to the invention, this is designed such that it can detect both tensile and compressive loadings which result between the two plates 2, 3 as a result of the rotational movement.

[0019] In order to pick up both tensile and compressive loadings, the force transducer 4 can be designed as a shear sensor. In particular, the one axial end 4.1 of the force transducer 4 can then be connected or connectable to the free end 2.1 of the one plate 2, and the other axial end 4.2 of the force transducer 4 can then be connected or connectable to the other free end 3.1 of the further plate 3, which is opposite the first plate. If then, as a result of a loading, the free end 2.1 of the plate 2 here moves toward the free end 3.1 of the plate 3, then a compressive loading is detected by the force transducer 4. The result is a torque M-, which acts in the counterclockwise direction and acts on the axis of rotation D. The angle which the two plates 2, 3 delimit with each other becomes smaller. If, in the opposite direction of rotation, the free end 2.1 of the plate 2 is rotated away from the free end 3.1 of the plate 3, then the force transducer 4 picks up a tensile force. This corresponds to a torque M+ in the clockwise direction around the axis of rotation D. The angle which the two plates 2, 3 delimit with each other becomes larger. The torque results from the fact that the force transducer 4 is not located in the axis of rotation D. As explained at the beginning, it is possible to draw conclusions about the magnitude of the web tension F.sub.z via the tensile or compressive loadings on the plates 2, 3 which results from the reaction forces on the bearing housing 8.1.

[0020] In principle, the following embodiment, not illustrated, would also be conceivable: instead of or in addition to the rotary joint 5 from FIG. 1, a further force transducer 4 would be provided. The axial ends 2.1, 3.1 of the plates 2, 3 could be designed analogously to FIG. 1. The rotary joint or the axis of rotation (also an imaginary one) would then be located between the two force transducers. The advantages according to the invention could also be implemented well with such an embodiment. Here, that already explained in relation to FIG. 1 is also analogously true. In both cases, only a single force transducer according to the invention is necessary for each free end of the plates.

[0021] Irrespective of the embodiment illustrated, it is advantageous if the axis of rotation D of the two plates is not located in a vertical plane onto the plates 2, 3 through the roll axis W but is at a distance therefrom. Thus, for example, the axis of rotation D can be chosen as shown in FIG. 1, such that it is located opposite the axial ends 2.1, 3.1 of the plates 2, 3. The force transducer 4 and the axis of rotation D of the web tension measuring device 1 lie in a plane which extends at right angles to a plane through the roll axis W. Here, the axis of rotation D extends outside and thus at a distance from said plane. In other words, the axis of rotation D can be arranged at the axial ends of the plates 2, 3 opposite the force transducer. In this way, in the installation position illustrated in FIG. 1, forces which act vertically on the plates through the roll axis W onto the web tension measuring device can also be determined by means of the web tension measuring device.