Device for or on a spinning preparation machine, in particular carding, drawing, combing or flyer, for correcting a measurement signal

Abstract

Device for or on a spinning preparation machine, in particular carding, drawing, combing or flyer, for correcting a measurement signal obtained from a pair of sensing rollers for the thickness of at least one textile fiber strip, in which one of the two sensing rollers (7, 15, 42) is stationary and the other sensing roller (8, 16, 43) is force-loaded and movable away from the stationary sensing roller (7, 15, 42) and the occurrence of a periodic error value caused by out-of-roundness and / or eccentricity of the pair of sensing rollers can be determined, wherein the pair of sensing rollers is connected to an electrical signal generation device (9, 47) (position sensor) and a rotary encoder (72), which send their signals to the input of an electronics unit and the output of the electronics unit provides the corrected measurement signal, characterized in that a contact is provided between a circumferential surface (7', 15', 42') of the stationary stylus roller (7, 15, 42) and a circumferential surface (8', 16',43') of the movable sensing roller (8, 16, 43) can be produced by pressing the movable sensing roller (8, 16, 43) against the stationary sensing roller (7, 15, 42) and the sensing rollers (7, 8; 15, 16; 42, 43) are rotatable under contact, and that the pair of sensing rollers comprises a grooved roller and a spring roller or two stepped rollers.

Description

[0001] The invention relates to a device for or on a spinning preparation machine, in particular a card, draw frame, comber or flyer, for correcting a measurement signal obtained from a pair of sensing rollers for the thickness of at least one textile fiber sliver, in which one of the two sensing rollers is stationary and the other sensing roller is force-loaded and movable away from the stationary sensing roller and the occurrence of a periodic error value caused by out-of-roundness and / or eccentricity of the pair of sensing rollers can be determined, wherein the pair of sensing rollers is connected to an electrical signal generator (position sensor) and a rotary angle sensor, which send their signals to the input of an electronic unit, and the output of the electronic unit supplies the corrected measurement signal.

[0002] In practice, the measurement of fiber sliver thickness is common, particularly for the purpose of correcting irregularities in one or more fiber slivers fed into a spinning preparation machine. Such a measurement is also desirable for quality control of the drawn material at the machine exit. In addition to the aforementioned quality control, measured values ​​for fiber sliver density or fiber sliver thickness are also used to shut down the machines if specified mass fluctuation values ​​are exceeded, thus resulting in a lower-quality product.

[0003] In a known device (DE 44 14 972 A1), the thickness of a fiber structure, e.g., consisting of at least one fiber sliver or a fiber fleece, is measured using a pair of sensing rollers. The pair of sensing rollers is designed such that a stationary, rotatable sensing roller is pivoted relative to the other, rotatable sensing roller. The two sensing rollers are preloaded with a spring. The pivoting sensing roller is deflected according to the thickness of the fiber sliver, which is guided between a pair of sensing rollers. The angle of the deflection is converted into an electrical signal, the measurement signal. Such a pair of sensing rollers is used, for example, upstream of a drafting system. The pair of sensing rollers advantageously has a mechanically simple design, is robust, and thus cost-effective. During operation of a pair of sensing rollers, the measurement signal can become corrupted.When a pair of sensing rollers is used as a mechanical sensor, it is known that tolerances in the sensing rollers and the sensing roller bearings can influence the measurement signal. Deviations from the ideal geometry of a sensing roller body can result in cross-sectional changes along the length of the cylindrical roller body. Likewise, deviations from a central mounting of the sensing rollers lead to eccentricity. The tolerances in the geometric dimensions of the sensing rollers overlap with the tolerances in the sensing roller bearings. These tolerances lead to a significant error in the measurement signal. This is a periodic error that occurs with each rotation of a sensing roller.To correct the erroneous measurement signal of the sensing roller pair, it is proposed that the occurrence of periodic error values ​​in the measurement signal of the fiber sliver caused by out-of-roundness and / or eccentricity of the sensing roller pair be determined and stored as an error value position-related with respect to one revolution of the sensing rollers. The stored error value is used to correct the current, position-synchronous measurement signals when the sensing rollers are in operation within the rotation cycles. The runout error is thus recorded in the measurement signal, i.e. it is determined using fiber material in the roller nip. It is assumed that with a sufficiently large number of measurements the sliver error adds up to zero due to the normal distribution and only the runout error of the roller remains. In the event that the measured values ​​do not follow the normal distribution, an error remains with this method. Another disadvantage is that the system complexity is high.Specifically, the electronics are equipped with modules for averaging values ​​from many revolutions, whereby the set of measurement signals is averaged over many revolution cycles. Furthermore, the inherent elasticity and unevenness of the fiber material passing through the roller gap results in undesirable fluctuations, which are added to the out-of-roundness of the sensing rollers. The runout error is detected indirectly. Finally, measuring the runout error requires numerous roller revolutions, which is time-consuming.

[0004] DE 842 849 B discloses a device for correcting a measurement signal from a pair of sensing rollers for the thickness of a passing fiber sliver. The device has a first stationary roller and two further rollers, each mounted at the end of an arm. The arms can pivot about a common pivot axis that is eccentric to the rotational axis of the first roller. A tension spring acts on the pivotable arms and tends to pivot them against each other, whereby the two further rollers are guided towards each other on a circular arc-shaped path of movement, approaching the circumference of the first roller. First, the extreme distance fluctuations caused by the out-of-roundness of the sensing rollers are determined, for example, by rotating the first roller of the device while no test object is located between the rollers.

[0005] The invention is therefore based on the object of creating a device of the type described above which avoids the disadvantages mentioned and which, in particular, enables the radial runout error to be determined and corrected in a simple manner and within a short time.

[0006] This problem is solved by the characterizing features of claim 1.

[0007] By determining the concentricity error directly, i.e., without fiber material, with rollers in contact, correction is possible in a simple and rapid manner. Advantageously, the contours of the circumferential surface of the two rollers are scanned directly through contact. The measures according to the invention elegantly eliminate the concentricity error completely or almost completely. The concentricity error is determined directly in the machine and calculated from the measurement signal by the control system.

[0008] Claims 2 to 54 contain advantageous developments of the invention.

[0009] The invention is explained in more detail below with reference to exemplary embodiments shown in the drawings.

[0010] It shows: Fig. 1 schematically shows a side view of a regulating section with the device according to the invention, Fig. 2 schematic side view of a card drafting system with the device according to the invention, Fig. 3a, Fig. 3b Side view of the device according to the invention as well as a stationary scanning roller and a pivoting scanning roller in production position ( Fig. 3a) and during the runout measurement ( Fig. 3b), Fig. 4 adjustable stop by pneumatic cylinder, Fig. 5 adjustable stop by actuator, Fig. 6 Loading of the movable take-off roller by means of a pneumatic cylinder and a spring-loaded stop, Fig. 7 a rotatable bearing housing for the movable scanning roller with associated sliding crank, Fig. 7a Section of the device according to Fig. 7 with adjustable stop, wherein the stop is locally relocated in such a way that the scanning rollers are in contact with each other according to Fig. 8 stand, Fig. 8 perspective view of the interacting scanning roller pair consisting of a stationary and a movable scanning roller in direct contact and their stationary or movable mounting and Fig. 9 schematic block diagram of a device for correcting the out-of-roundness of the scanning rollers.

[0011] After Fig. 1 comprises a draw frame 1, e.g., Trützschler draw frame TD 03, a drafting system 2, which is preceded by a drafting system inlet 3 and followed by a drafting system outlet 4. The fiber slivers 5 exit from cans (not shown) into the sliver guide 6 and, pulled by the take-off rollers 7, 8, are transported past the measuring element (distance sensor 9). The drafting system 2 is designed as a 4-over-3 drafting system, i.e., it consists of three bottom rollers I, II, III (I output bottom roller, II middle bottom roller, III input bottom roller) and four top rollers 11, 12, 13, 14. The drafting of the fiber strand 5 takes place in the drafting system 2. IVfrom several fiber slivers 5. The draft consists of pre-draft and main draft. The roller pairs 14 / III and 13 / II form the pre-draft zone, and the roller pairs 13 / II and 11, 12 / I form the main draft zone. In the pre-draft zone, the fiber strand 5' is drawn, and in the main draft zone, the fiber strand 5'' is drawn. The drawn fiber slivers 5''' reach a web guide 10 in the drafting system outlet 4 and are pulled through a sliver funnel 17 by the take-off rollers 15, 16, where they are gathered into a fiber sliver 18, which is then deposited in cans. A denotes the working direction.

[0012] The take-off rollers 7, 8, the input lower roller III, and the middle lower roller II, which are mechanically coupled, e.g., via toothed belts, are driven by the control motor 19, whereby a setpoint can be specified. (The associated upper rollers 14 and 13 also run.) The output lower roller I and the take-off rollers 15, 16 are driven by the main motor 20. The control motor 19 and the main motor 20 each have their own controller 21 and 22, respectively. The control (speed control) is carried out via a closed control loop, with a tachogenerator 23 assigned to the controller 19 and a tachogenerator 24 assigned to the main motor 20. At the drafting system inlet 3, a quantity proportional to the mass, e.g., the cross-section of the fed-in fiber slivers 5, is measured by an inlet measuring device. At the drafting system outlet 4, the cross-section (thickness) of the exited fiber sliver 18 is obtained by an outlet measuring device (distance sensor 25) assigned to the take-off rollers 15, 16.A central computer unit 26 (control and regulation device), e.g., a microcomputer with a microprocessor, transmits a setting of the target value for the control motor 19 to the controller 21. The measured values ​​of the two measuring elements 9 and 25 are transmitted to the central computer unit 26 during the drawing process. The setpoint for the control motor 19 is determined in the central computer unit 26 from the measured values ​​of the inlet measuring element 9 and the target value for the cross-section of the exiting fiber sliver 18. The measured values ​​of the exit measuring element 25 are used to monitor the exiting fiber sliver 18 (output sliver monitoring) and to determine the optimal pre-draft online. With the help of this control system, fluctuations in the cross-section of the fed-in fiber slivers 5 can be compensated for by appropriately controlling the drawing process, or a homogenization of the fiber sliver can be achieved.27 denotes a screen, 28 an interface, 29 an input device, and 30 a pressure bar. The measured values ​​from the measuring element 25, e.g., thickness variations of the fiber sliver 18, are fed to a memory 31 in the computer 26.

[0013] The take-off rollers 7, 8 at the entrance and the take-off rollers 15, 16 at the exit of the draw frame each have a dual function; they serve to take off the respective fiber strand 5 IV or 18 and simultaneously feel the respective fiber structure 5 IV or 18. The cross-section or the mass of the fiber band 18, which passes through the nip a between the take-off rolls 15, 16 during operation, are determined with the Fig. 3a, Fig. 3b. The same applies to determining the cross-section or mass of the fiber structure 5 IV(consisting of several fiber bands), which passes through the nip a between the take-off rollers 7, 8, can Fig. 3a, Fig. The device shown in Figure 3b can be used.

[0014] The take-off rollers 7, 8 and / or the take-off rollers 15, 16 are designed to determine the run-out error in the manner according to the invention.

[0015] Fig. Figure 2 shows an embodiment in which a card drafting system 36 is arranged between a card, e.g., a Trützschler TC 07, and the delivery plate 35 above the delivery plate 35. The card drafting system 36 is designed as a 3-over-3 drafting system, i.e., it consists of three bottom rollers I, II, and III and three top rollers 37, 38, 39. An inlet funnel 40 is arranged at the inlet of the drafting system 36, and an outlet funnel 41 is arranged at the outlet of the drafting system. Following the outlet funnel 41 are two take-off rollers 42, 43, which rotate in the direction of the curved arrows and draw the drawn fiber sliver 44 from the outlet funnel 41. The output bottom roller I, the take-off rollers 42, 43, and the delivery plate 35 are driven by a main motor 45, while the input and middle bottom rollers III and II are driven by a control motor 46. The motors 45 and 46 are connected to an electronic control and regulation device (not shown). The cross-section orthe mass of the fiber band 44 passing through the nip between the take-off rollers 42, 43 are - according to the . Fig. 3a, Fig. 3b - with the distance sensor 47. The distance sensor 47 is connected to the electronic control and regulating device (not shown), which is assigned to the central computer unit 26 (see Fig. 1). B denotes the working direction. The take-off rollers 42, 43 are designed to determine the concentricity error in the manner according to the invention.

[0016] The Fig. 1 and Fig. 2 show an embodiment in which the stationary scanning roller 7, 15 or 42 (or the bearing housing 52 for the stationary scanning roller 15 according to Fig. 7 and Fig. 8) an electrical signal generating device 9, 25 or 47 in the form of a distance sensor 57 in Fig. 7 and Fig. 8 is assigned.

[0017] Accordingly Fig. 3a, Fig. 3b there is a stationary scanning roller 7 and a pivoting scanning roller 8, which are arranged according to Fig. 3c are designed as a grooved (touch roller 8) and a spring (touch roller 7) roller. Between the circumferential surface 8' in the groove base of the touch roller 8 and the circumferential surface 7' on the periphery of the touch roller 7 there is a distance a through which the fiber material passes during operation. There is a pivotable holding element 60 which is designed as a single-armed lever 60, which is mounted at one end on a stationary pivot bearing 61 in the direction of the arrows L, M. The shaft journal 8a of the touch roller 8 is attached to the lever arm 60. A compression spring 62 is supported at one end on section 60a of the lever arm 60, the other end of which is supported on a fixed bearing 63. The other section 60b of the lever arm 60 is assigned an inductive displacement sensor 64 as a displacement sensor, which is connected to an electronics unit (see Fig. 9) is electrically connected. On the side of the lever arm 60a facing the stationary scanning roller 7, there is a stop element 65, which ensures the distance a between the scanning rollers 7 and 8 during operation.

[0018] To detect a concentricity error of the scanning roller 7 and / or the scanning roller 8, the stop element 65 is Fig. 3b (in a manner not shown) so that contact is created between the circumferential surface 7' of the stationary sensing roller 7 and the circumferential surface 8' in the groove base of the movable sensing roller 8 as a result of the pressure exerted by the compression spring 62. The sensing rollers 7 and 8 are then rotated completely once around their shafts 7a and 8a, e.g. manually or by motor (in a manner not shown). In the event of out-of-roundness of one or both sensing rollers 7, 8, the movable sensing roller 8 and with it the lever arm 60 are deflected accordingly in directions E, F against or in the direction of the compression spring 62. This displacement, which the plunger 64a experiences in the same way, changes the induction in the plunger coil 64b, so that an electrical signal is sent to the electronics (see Fig. 9) is submitted.

[0019] After Fig. 4, an adjustable stop 65 is provided by means of a pneumatic cylinder 74. The stop 65 can be moved in the direction of arrows I, K.

[0020] Accordingly Fig. 5, the stop 65 is adjustable with an actuator 72 in the direction of arrows I, K. The actuator 72 can be implemented, for example, by a motor, gear with rack, or the like.

[0021] According to Fig. 6, the loading of the movable scanning roller 7 is provided by a pneumatic cylinder 74, which is pivoted on the lever arm 60a. A stop 65, which is force-loaded by a spring 75 (compression spring), is assigned to the lever arm 60b.

[0022] The Fig. 7, Fig. 7a and Fig. 8 show a device for continuously determining the cross-section or the mass of a (in the Fig. 1 and Fig. 2) fibre structure made of at least one fibre band, with a pair (in the Fig. 1 and Fig. 2) scanning rollers 15, 16. The shafts belonging to the shaft journals 15a and 16a (not shown) are rotatably mounted in roller bearings 50 and 51, respectively, which in turn are mounted in bearing housings 52 and 53, respectively. The bearing housing 52 is stationary, while the bearing housing 53 is arranged so as to be rotatable (pivotable) in the direction of arrows C, D about a stationary pivot bearing 54. The pivot bearing 54 is fastened to a stationary support 49. The rotatable bearing housing 53 is loaded and prestressed by a spring 55, one end of which is supported on an abutment 56.

[0023] In this way, the bearing housing 53 and, with it, the sensing roller 15 can be moved away essentially in a straight line. An inductive (non-contact) analog distance sensor 57 is integrated into the stationary bearing housing 52, the sensor surface 57a of which faces the facing surface 53' of the bearing housing 53. Between the sensor surface 57a and the surface 53', a variable distance a, e.g., approximately 1 mm, exists in the operating state, which distance is measured by the distance sensor 57. In this way, one of the rollers, roller 15, is stationary, and the other roller, roller 16, can be moved away from it essentially in a straight line. The bearing housing 52 and the support 49 are fixedly mounted on the machine frame (not shown). In the open state (not shown when not in operation), the distance is, for example, approximately 11 mm.70 denotes a sliding crank for opening, 58 denotes the line of the distance sensor 57, and 48a, 48b denote two toothed belt pulleys for driving (via a toothed belt not shown) the sensing rollers 15, 16. The toothed belt coupling ensures synchronous operation of the sensing rollers 15, 16.

[0024] To detect a concentricity error of the scanning rollers 1 and / or scanning roller 16, the stop element 59 is Fig. 7a is withdrawn from the surface 53' of the pivoting bearing housing 53 in the direction G by an adjusting screw 71, whereby a distance b is present between the end face 59' of the stop element 59 and the surface 53' and at the same time Fig. 8, a contact occurs between the circumferential surface 15' of the stationary scanning roller 15 and the circumferential surface 16' of the movable scanning roller 16 as a result of the pressure exerted by the compression spring 55. The distance a (operating state) between the bearing housings 52 and 53 is thereby reduced to the distance a' (see Fig. 7a). Subsequently, the scanning rollers 15, 16 are rotated completely and slowly once, e.g., by the main motor 20 via the toothed belt wheels 48a, 48b with a toothed belt (not shown). The distance sensor 57 detects the changes in the distance a' due to out-of-roundness and transmits corresponding electrical pulses via line 58 to the electronics ( Fig. 9).

[0025] The device according to the invention with the Fig. The configurations shown in Figures 1 to 8 can be arranged at the inlet and / or outlet of a drafting system which is a component of a carding machine, draw frame, combing machine, roving frame or other spinning preparation machine.

[0026] With the curved arrows, e.g. 7b, 8b ( Fig. 3b), the directions of rotation of the rollers are indicated.

[0027] After Fig.9, the distance sensor 57 (if necessary via a digital-to-analog converter, not shown) and an angle sensor 72 are connected to the control and regulating device 26 (electronics). The control and regulating device 26 (microcomputer with microprocessor) contains a memory 73 and a correction element 74. The distance sensor 57 is connected to the memory 73 and the correction element 74, and the angle sensor 72 is connected to the correction element 74. During operation, the correction element 74 supplies corrected signals to the control motor 19. 75 designates a switching device that switches from the learning phase (without fiber material) to the operating phase (with fiber material).

[0028] According to the invention, the concentricity error is determined directly in the machine and calculated by the control system 26 from the measurement signal. For this purpose, the rollers are briefly moved directly against each other and rotated slowly. The measuring system used for strip measurement determines the concentricity deviation caused by the rollers, shafts, and bearings. The data is recorded by the control system 26 and taken into account in the strip measurement.

[0029] The rollers can be moved toward each other, for example, by removing the stop during the runout measurement. After the runout measurement, the stop can be reactivated to ensure the smallest possible base distance between the rollers. Removal can be achieved, for example, using a pneumatic cylinder, actuator, magnetic switch, or a spring-loaded stop.

[0030] To prevent damage to the two rolls that touch during the runout measurement, the calendering pressure can be reduced to a minimum during the measurement. This can be achieved using a pneumatic cylinder that generates a small force during the runout measurement and a large force otherwise. The pneumatic cylinder could also increase its force during the runout measurement to overcome the force of the spring-loaded stop.

[0031] This concentricity measurement can be performed at regular intervals, allowing changes in the concentricity error, e.g., due to roller replacement, wear, or contamination, to be continuously detected. This ensures precise belt measurement over the long term.

Claims

[1] Device for or on a spinning preparation machine, in particular a card, draw frame, combing machine or flyer, for correcting a measurement signal obtained from a pair of sensing rollers for the thickness of at least one textile fibre sliver, in which one of the two sensing rollers (7, 15, 42) is stationary and the other sensing roller (8, 16, 43) is force-loaded and movable away from the stationary sensing roller (7, 15, 42), and the occurrence of a periodic error value caused by out-of-roundness and / or eccentricity of the pair of sensing rollers can be determined, wherein the pair of sensing rollers is connected to an electrical signal-forming device (9, 47) (displacement sensor) and a rotary angle sensor (72), which send their signals to the input of an electronic unit, and the output of the electronic unit supplies the corrected measurement signal, characterized bythat a touching contact between a circumferential surface (7', 15', 42') of the stationary sensing roller (7, 15, 42) and a circumferential surface (8', 16', 43') of the movable sensing roller (8, 16, 43) can be produced by pressing the movable sensing roller (8, 16, 43) against the stationary sensing roller (7, 15, 42) and the sensing rollers (7, 8; 15, 16; 42, 43) are rotatable with touching contact, and that the sensing roller pair comprises a grooved roller and a spring roller or two stepped rollers. [2] Device according to claim 1, characterized by that position-related measuring signals of the path deflection of the movable sensing roller (8, 16, 43) can be formed when the distance between the centers of the sensing rollers (7, 8; 15, 16; 42, 43) changes. [3] Device according to claim 2, characterized by that the position-related measuring signals can be formed for at least one revolution of the sensing rollers (7, 8; 15, 16; 42, 43). [4] Device according to one of claims 2 or 3, characterized bythat the position-related measuring signals of the path deflection can be formed when the contour of the circumferential surface (7', 15', 42'; 8', 16', 43') of at least one sensing roller (7, 8; 15, 16; 42, 43) changes. [5] Device according to one of claims 1 to 4, characterized by that a standard roller without deviations from a target value is used to determine a deflection caused by the out-of-roundness of the sensing rollers (7, 8; 15, 16; 42, 43). [6] Device according to one of claims 1 to 5, characterized by that one of the two scanning rollers (7, 8; 15, 16; 42, 43) is mounted so as to be rotatable or pivotable. [7] Device according to one of claims 1 to 6, characterized by that the movable scanning roller (8, 16, 43) can be pressed against the stationary scanning roller (7, 15, 42) by means of a force means (55, 62, 75). [8] Device according to one of claims 1 to 7, characterized bythat the electrical signal generating device (9, 47) is assigned to the movable sensing roller (8, 16, 43) or to a holding element (53, 60) for the movable sensing roller (8, 16, 43). [9] Device according to one of claims 1 to 8, characterized by that the electrical signal generating device (57) is assigned to the stationary scanning roller (7, 15, 42) or to a holding element (52) for the stationary scanning roller (7, 15, 42). [10] Device according to one of claims 3 to 9, characterized by that at least one revolution of the scanning rollers (7, 8; 15, 16; 42, 43) for determining the periodic error value can be carried out manually. [11] Device according to one of claims 3 to 10, characterized by that at least one revolution of the scanning rollers (7, 8; 15, 16; 42, 43) for determining the periodic error value can be carried out by a motor. [12] Device according to one of claims 1 to 11, characterized bythat in the event of out-of-roundness of at least one sensing roller (7, 8; 15, 16; 42, 43), the periodic error value in the measurement signal of the path deflection of the movable sensing roller (8, 16, 43) can be generated in contact with the stationary sensing roller (7, 15, 42). [13] Device according to one of claims 1 to 12, characterized by that the path deflection of the movable sensing roller (8, 16, 43) caused by the out-of-roundness of at least one sensing roller (7, 8; 15, 16; 42, 43) can be converted into an electrical measuring signal by an electrical signal generating device (9, 47). [14] Device according to one of claims 1 to 13, characterized by that a signal processing reacts to the electrical measurement signal of the path deflection of the movable sensing roller (8, 16, 43) upon contact with the stationary sensing roller (7, 15, 42). [15] Device according to claim 14, characterized bythat the periodic error value contained in the electrical measurement signal can be determined by means of signal processing. [16] Device according to one of claims 1 to 15, characterized by that the periodic error value can be stored in a memory of an electronic control and regulating device (26) in a position-related manner with respect to one revolution of the sensing rollers (7, 8; 15, 16; 42, 43). [17] Device according to claim 16, characterized by that the stored error value can be used during operation of the sensing rollers (7, 8; 15, 16; 42, 43) in a correction element of the electronic control and regulating device (26) for correcting the current, position-synchronous measuring signal of the density fluctuations of the fiber material. [18] Device according to one of claims 16 or 17, characterized bythat the electrical signal forming device (9, 47) is capable of supplying the electrical measurement signal of the path deflection of the movable sensing roller (8, 16, 43) to an A / D converter when in contact with the stationary sensing roller (7, 15, 42). [19] Device according to claim 18, characterized by that the A / D converter is connected to the electronic control and regulating device (26). [20] Device according to one of claims 1 to 19, characterized by that the rotary angle sensor (72) is coupled to the movable scanning roller (8, 16, 43). [21] Device according to one of claims 16 to 20, characterized by that the rotary angle sensor (72) is connected to the control and regulating device (26). [22] Device according to one of claims 16 to 21, characterized by that the rotary angle sensor (72) is integrated into the electronic control and regulating device (26). [23] Device according to one of claims 1 to 22, characterized bythat the scanning rollers (7, 8; 15, 16; 42, 43) are forcibly connected to one another, e.g. by toothed belt coupling or the like. [24] Device according to one of claims 1 to 23, characterized by that the scanning rollers (7, 8; 15, 16; 42, 43) can be moved briefly directly onto one another to determine the out-of-roundness. [25] Device according to one of claims 1 to 24, characterized by that the scanning rollers (7, 8; 15, 16; 42, 43) are slowly rotatable during the determination of the out-of-roundness. [26] Device according to one of claims 1 to 25, characterized by that a stop element (59, 65) (spacer) is removable for moving the scanning rollers (7, 8; 15, 16; 42, 43) towards one another. [27] Device according to claim 26, characterized by that a pneumatic cylinder, actuator, magnetic switch or the like can be used to remove the stop element (59, 65). [28] Device according to one of claims 26 or 27, characterized bythat the stop element (59, 65) is spring-loaded. [29] Device according to one of claims 1 to 28, characterized by that the pressure of the sensing rollers (7, 8; 15, 16; 42, 43) is reduced to a minimum during contact. [30] Device according to one of claims 1 to 29, characterized by that a pressure element (74) is able to exert a small force during the determination of the out-of-roundness (contacting contact) and a large force during operation (contact in the fiber material). [31] Device according to claim 30, characterized by that during the concentricity error measurement, the force of the pressure element (74) designed as a pneumatic cylinder can be increased in order to overcome the force of the spring-loaded stop element (65). [32] Device according to one of claims 26 to 28, characterized bythat the stop element (59, 65) is capable of generating a basic distance between the circumferential surfaces (7', 15', 42'; 8', 16', 43') of the sensing rollers (7, 8; 15, 16; 42, 43) (roll gap) after the runout error measurement. [33] Device according to one of claims 8 to 32, characterized by that the signal generating device (9, 47) comprises a contactless distance sensor (57) for measuring the distance from a counter surface (53') (scanning surface) which is assigned to the holding element (53) for one of the scanning rollers (7, 8; 15, 16; 42, 43). [34] Device according to claim 33, characterized by that the distance sensor (57) is assigned to the holding element (53) for the other scanning roller (8, 16, 43). [35] Device according to one of claims 33 or 34, characterized by that the distance sensor (57) and the counter surface (53') are arranged on the side of the holding elements (52, 53) facing each other. [36] Device according to one of claims 33 to 35, characterized by that the distance sensor (57) is integrated into the holding element (52, 53) for one of the scanning rollers (7, 8; 15, 16; 42, 43). [37] Device according to one of claims 33 to 36, characterized by that the counter surface is assigned to the holding element (53) for one sensing roller (7, 15, 42), the distance sensor (57) is assigned to the holding element (52) for the other sensing roller (8, 16, 43) and the distance sensor (57) and the counter surface are arranged on the side of the holding elements (52, 53) facing each other. [38] Device according to one of claims 33 to 37, characterized by that the distance sensor (57) is stationary and the counter surface (53') is movable relative to the distance sensor (57) [39] Device according to one of claims 33 to 38, characterized by that the distance sensor (57) is movable and the counter surface is stationary relative to the distance sensor (57). [40] Device according to one of claims 33 to 39, characterized by that the distance sensor (57) is able to detect the change in induction. [41] Device according to one of claims 33 to 40, characterized by that the distance sensor (57) is an inductive proximity switch. [42] Device according to one of claims 33 to 41, characterized by that an optical distance sensor (distance measuring sensor) is used as the distance sensor (57). [43] Device according to one of claims 33 to 42, characterized by that the distance sensor (57) is an analogue sensor. [44] Device according to one of claims 1 to 43, characterized by that the spinning preparation machine is a regulated card, a card with a regulated drafting system, a comber with a regulated drafting system or a draw frame. [45] Device according to one of claims 1 to 44, characterized bythat the determination of the sliver mass of a moving fibre sliver is provided on a spinning preparation machine with several successive drafting devices for drawing the fibre sliver. [46] Device according to one of claims 1 to 45, characterized by that axes of the scanning rollers (7, 8; 15, 16; 42, 43) are arranged horizontally. [47] Device according to one of claims 1 to 45, characterized by that axes of the scanning rollers (7, 8; 15, 16; 42, 43) are arranged vertically. [48] ​​Device according to one of claims 46 or 47, characterized by that the axes of the scanning rollers (7, 8; 15, 16; 42, 43) are arranged parallel to each other. [49] Spinning preparation machine, in particular carding machine, draw frame or combing machine, for use with the device according to one of the preceding claims, with at least one distance sensor (57) for measuring the out-of-roundness of the pair of sensing rollers. [50] Spinning preparation machine according to claim 49, characterized by that at least one of the scanning rollers (7, 8; 15, 16; 42, 43) is driven. [51] Spinning preparation machine according to one of claims 49 or 50, characterized by that the two sensing rollers (7, 8; 15, 16; 42, 43) are simultaneously arranged as take-off rollers directly downstream of a funnel-shaped belt guide (6), fleece guide (10) or the like. [52] Spinning preparation machine according to one of claims 49 to 51, characterized by that the distance sensor (57) determines the distances to a counter element opposite the sensor surface. [53] Spinning preparation machine according to one of claims 49 to 52, characterized by that the circumferential surfaces (7', 15', 42'; 8', 16', 43'), which are in direct contact with one another during the runout error determination, are in contact with the fiber material during operation. [54] Spinning preparation machine according to one of claims 49 to 53, characterized by that more than one revolution of the sensing rollers (7, 8; 15, 16; 42, 43) is provided for the concentricity error determination and an averaging device is provided in the electronics (26).

Images