Method and device for measuring the fabric tension in a weaving machine

Abstract

Method for measuring the fabric tension in a weaving machine, in which the fabric (1) is deflected by a deflecting shaft (2), wherein a bending force is applied onto the deflecting shaft (2) by the fabric (1). The flexure or bending displacement of the deflecting shaft (2) is measured by a sensor (3), which is arranged in an area between two supports (4.1, 4.2) of the deflecting shaft (2) on the weaving machine. The deflecting shaft (2) is connected with a machine frame (9) of the weaving machine via the two supports (4.1, 4.2). The spacing distance (A) between the two supports (4.1, 4.2) of the deflecting shaft (2) is reduced for larger fabric tensions to be measured and is increased for smaller fabric tensions to be measured. Furthermore, the invention relates to a corresponding weaving machine.

Claims

1. Method for measuring the fabric tension in a weaving machine, in which the fabric (1) is deflected by a deflecting shaft (2), wherein a bending force is applied by the fabric (1) onto the deflecting shaft (2), and wherein the flexure or bending displacement of the deflecting shaft (2) is measured by a sensor (3), which is arranged in an area between two supports (4.1, 4.2) of the deflecting shaft (2) on the weaving machine, wherein the deflecting shaft (2) is connected with a machine frame (9) of the weaving machine via the two supports (4.1, 4.2), characterized in that the spacing distance (A) between the two supports (4.1, 4.2) of the deflecting shaft (2) is reduced for larger fabric tensions to be measured and is increased for smaller fabric tensions to be measured.

2. Method according to claim 1, wherein the two outer ends of the deflecting shaft (2) are additionally supported by two stationary outer supports (14.1, 14.2).

3. Method according to claim 1, wherein the operator inputs an information about the current spacing distance (A) between the two supports (4.1, 4.2) of the deflecting shaft (2) or about the current measuring range into the controller (5) of the weaving machine.

4. Method according to claim 1, wherein markings (6) are applied on the weaving machine, from which the operator can obtain informations about the current spacing distance (A) between the two supports (4.1, 4.2) of the deflecting shaft (2) or about the current measuring range.

5. Method according to claim 1, wherein the current spacing distance (A) between the two supports (4.1, 4.2) of the deflecting shaft (2) or the position of at least one support (4.1) is measured and electrically conveyed further to the controller (5) of the weaving machine by measuring elements (7).

6. Method according to claim 1, wherein the flexure or bending displacement of the deflecting shaft (2) is transmitted to the sensor (3) by a transmission element (8) in such a manner so that the measurement distance (D) of the transmission element (8) effective at the sensor (3) is larger than the actual flexure or bending displacement on the deflecting shaft (2).

7. Method according to claim 6, wherein a transmission lever (8) with two lever ends is used as the transmission element (8), wherein the first lever end is connected with a machine frame (9) of the weaving machine, while the second lever end is freely movable, and wherein the sensor (3) is arranged at a spacing distance from the deflecting shaft (2), while the transmission lever (8) is arranged between deflecting shaft (2) and sensor (3) in such a manner so that the second lever end of the transmission lever (8) lies closer to the sensor (3), while the first lever end lies closer to the deflecting shaft (2).

8. Weaving machine with a measuring device for measuring the fabric tension in a weaving machine, with a deflecting shaft (2) for deflecting the fabric (1), which applies a bending force onto the deflecting shaft (2), with a sensor (3) for measuring the flexure or bending displacement of the deflecting shaft (2), wherein the sensor (3) is arranged in an area between two supports (4.1, 4.2) of the deflecting shaft (2) on the weaving machine, and wherein the deflecting shaft (2) is connected with a machine frame (9) of the weaving machine via the two supports (4.1, 4.2), characterized in that the spacing distance (A) between the two supports (4.1, 4.2) of the deflecting shaft (2) is reducible for larger fabric tensions to be measured and increasable for smaller fabric tensions to be measured.

9. Weaving machine according to claim 8, characterized in that the two outer ends of the deflecting shaft (2) are additionally supported by two stationary outer supports (14.1, 14.2).

10. Weaving machine according to claim 8, characterized by an input device (5a) for the inputting of an information about the current spacing distance (A) between the two supports (4.1, 4.2) of the deflecting shaft (2) or about the current measuring range into the controller (5) of the weaving machine.

11. Weaving machine according to claim 8, characterized in that markings (6) are applied on the weaving machine, from which the operator can obtain informations about the current spacing distance (A) between the two supports (4.1, 4.2) of the deflecting shaft (2) or about the current measuring range.

12. Weaving machine according to claim 8, characterized by at least one measuring element (7), especially at least one light emitter, for measuring the current spacing distance (A) between the two supports (4.1, 4.2) of the deflecting shaft (2) or the position of at least one support (4.1), and for electrically conveying to the controller (5) of the weaving machine.

13. Weaving machine according to claim 8, characterized by a transmission element (8) for transmitting the flexure or bending displacement of the deflecting shaft (2) to the sensor (3) in such a manner so that the measuring distance (D) of the transmission element (8) effective at the sensor (3) is larger than the actual flexure or bending displacement on the deflecting shaft (2).

14. Weaving machine according to claim 13, characterized in that the transmission element (8) is equipped as a transmission lever (8) with two lever ends, wherein the first lever end is connected with a machine frame (9) of the weaving machine, while the second lever end is freely movable, and wherein the sensor (3) is arranged at a spacing distance from the deflecting shaft (2), while the transmission lever (8) is arranged between deflecting shaft (2) and sensor (3) in such a manner so that the second lever end of the transmission lever (8) lies closer to the sensor (3), while the first lever end lies closer to the deflecting shaft (2).

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 schematic illustration of a weaving machine with an apparatus or device for carrying out the method according to the invention, view B-B;

(2) FIG. 2 view A-A of the weaving machine according to FIG. 1, however without fabric;

(3) FIG. 3 enlarged cut-away portion of FIG. 1.

ADVANTAGEOUS EMBODIMENT OF THE INVENTION

(4) The FIGS. 1 to 3 will be described together in common in the following.

(5) Warp threads 11 are drawn-off from a warp beam that is not illustrated, and are guided through shedding elements 12 in such a manner so that the warp threads 11 form a loom shed, into which a weft thread is inserted. The weft thread is beat-up by a weaving reed 10 against a fabric edge or interlacing point. The fabric 1 is delivered over a fabric table 15 and a deflecting shaft 2 to a feed or drawing-in roller 13. The deflecting shaft 2 can also comprise a threading or obliquely extending grooves, by which the fabric 1 is spread out in the weft direction. The deflecting shaft 2 is supported via two inner supports 4.1, 4.2 that are adjustable in the spacing distance relative to one another, and two stationary outer supports 14.1, 14.2 as well as a guide profile 18 in the machine frame 9 of the weaving machine.

(6) The feed or drawing-in roller 13 and the warp beam are connected with drives that are not illustrated. These drives are actuated by the controller 5 of the weaving machine in such a manner so that the warp threads 11 and the fabric 1 connected with the warp threads 11 are tensioned in the warp direction. The magnitude of the fabric tension is a measure for the magnitude of the warp tension or the warp thread tension forces on the weaving machine.

(7) Due to the deflection of the tensioned fabric 1 over the deflecting shaft 2 in an area between the two supports 4.1, 4.2, there arises a bending force that causes an elastic flexure or bending of the deflecting shaft 2. The deflecting shaft 2 is connected with a transmission lever 8, which enlarges the flexure or bending displacement or the magnitude of the elastic deformation of the deflecting shaft 2. In the present example, the transmission lever 8 consists of a bendable metal sheet that is clamped-in at its first end on the machine frame 9. The metal sheet comprises a curved or bent portion that acts like a bending spring. Thereby the transmission lever 8 is connected elastically at its first end with the machine frame 9. The second end of the metal sheet is freely movable, at least in the direction of the flexure or bending displacement of the deflecting shaft 2. The transmission lever 8 is arranged so that a flexure or bending of the deflecting shaft 2 leads to a sliding displacement of the transmission lever 8. Upon a flexure or bending of the deflecting shaft 2, respective sliding displacements of the transmission lever 8 that extend approximately in the shape of a circular arc, arise at the freely movable second end of the transmission lever 8 and at the point at which the deflecting shaft 2 engages on the transmission lever 8. The second end of the transmission lever 8 is spaced farther away from the clamping-in location on the machine frame 9 than the point or the area at which the deflecting shaft 2 is connected with the transmission lever 8. Through this arrangement, differently sized sliding displacements arise for the above described circular arc-shaped sliding displacements depending on the spacing distance of the connection location of the transmission lever 8 with the machine frame 9. The arrangement of the deflecting shaft 2, a sensor 3 that is explained further below, and the transmission lever 8 is selected so that a flexure or bending of the deflecting shaft 2 causes a larger sliding displacement at the free end of the transmission lever 8 than the sliding displacement at the point or in the area at which the deflecting shaft 2 is connected with the transmission lever 8.

(8) The already mentioned sensor 3, which detects the measurement distance D of the free lever end in the direction of the flexure or bending of the deflecting shaft 2, is arranged in the proximity of the free second end of the transmission lever 8. Through the lever transmission ratio of the transmission lever 8, it is also possible to utilize such sensors 3 that only emit a measurement signal for larger measurement distances D, in the present example this is an inductive distance transducer. That is an element that causes lower costs than, for example, a high-sensitivity strain gage that could be secured directly on the bottom side of the deflecting shaft 2, in order to measure the very small strains that arise there as a result of the flexure or bending. The measured flexure or bending is a measure for the fabric tension or for the warp tension of the fabric 1 that is currently deflected over the deflecting shaft 2 in the weaving machine.

(9) The actually arising flexure or bending of the deflecting shaft 2 is, however, also dependent on the spacing distance A of the supports 4.1, 4.2, between which the flexure or bending is measured.

(10) In the present example, the supports 4.1, 4.2 are releasably connected via screws 16 with a cross-girder of the machine frame 9. By a sliding displacement of the supports 4.1, 4.2 in a guide profile 18 of the cross-girder, the operator can make the spacing distance A between the supports 4.1, 4.2 larger or smaller. As an auxiliary aid in this process, a measurement scale is applied on the guide profile. This measurement scale includes several markings 6, which are respectively brought into alignment with an edge of the respective support 4.1, 4.2 by the operator of the weaving machine, in order to adjustingly set various different spacing distances of the supports 4.1, 4.2 and therewith various different prescribed measuring ranges for the fabric tension to be measured, according to the invention.

(11) The operator inputs the respective adjustingly set support spacing distance A into the weaving machine controller 5 via an input device 5a (e.g. touch panel). Then, in the controller 5, the signals of the sensor 3 corresponding to the adjusted spacing distance A are transformed by calculation into a flexure or bending or a fabric tension.

(12) The markings 6 can also be embodied or configured so that the measuring range, that is to say a maximum value and minimum value of the fabric tension that arises from the adjusted support spacing distance A, is directly readable therefrom. In this case, the operator inputs the adjusted measuring range via the mentioned input device 5a directly into the controller 5 of the weaving machine.

(13) Especially advantageous is an optional arrangement of one or more measuring elements 7 for the direct measurement of the support spacing distance A or for the measurement of the current spacing distance of one or both supports 4.1, 4.2 to the sensor 3. As an example, in FIGS. 1 to 3 a light emitter is illustrated as a measuring element 7. The light emitter 7 is arranged on the base body of the sensor 3 for the flexure or bending between the two supports 4.1, 4.2 of the deflecting shaft 2. The measuring element 7 measures the spacing distance to the support 4.1. For this purpose, suitably a reflector surface for the light beam of the light emitter 7 is present on this support 4.1. The other support 4.2 is adjustingly set by the operator symmetrically to the sensor 3 on the guide profile. Thus, the measured spacing distance of the one support 4.1 to the sensor 3 corresponds to half of the spacing distance A between the two supports. The measured spacing distance is conveyed electrically further to the weaving machine controller 5 and there is transformed by calculation into a measuring range for the fabric tension.

(14) In the present example, the deflecting shaft 2 is secured with the aid of clamping jaws and clamping screws 17 on the supports 4.1, 4.2. A variation of the support spacing distance A is possible without thereby changing the position of the deflecting shaft 2 relative to the sensor 3 or relative to the weaving machine. The sensor 3 and the transmission lever 8 are similarly secured on the guide profile 18 of the machine frame 9.

REFERENCE NUMBERS

(15) 1 fabric 2 deflecting shaft 3 sensor for flexure or bending 4.1, 4.2 supports 5 controller of the weaving machine 5a input device 6 marking 7 measuring element for support spacing distance 8 transmission lever 9 machine frame 10 weaving reed 11 warp threads 12 shedding elements 13 feed or drawing-in roller 14.1, 14.2 outer supports 15 fabric table 16 screw connection of the supports 17 clamp screw for deflecting shaft 18 guide profile A spacing distance between supports D measurement distance