Method for controlling the mass of a sliver in an integrated drafting system of a carding machine

Abstract

The invention relates to a method for controlling the mass of a sliver (FB) in an integrated drafting system (1) of a carding machine (K), comprising a pair of input measuring rollers (6a, 6b) upstream of a main drafting zone of the drafting system, and comprising a pair of output measuring rollers (15a, 15b) downstream of the main drafting zone, wherein the mass of the sliver (FB) at the pair of input measuring rollers (15a, 15b) forms the reference variable and the draft of the drafting system forms the manipulated variable, wherein a change in the mass of the sliver (FB) at the pair of input measuring rollers (6a, 6b) causes a change in the manipulated variable in the control system of the carding machine (K), and the magnitude of the change in the manipulated variable in the control system of the carding machine (K) is stored in the form of a graph or curve which is defined by at least two parameters. The invention also relates to a drafting system for carrying out the method.

Description

[0001] Title: Method for controlling the mass of a sliver in an integrated drafting system of a card

[0002] Description

[0003] The present invention relates to a method for controlling the mass of a fiber sliver in an integrated drafting system of a carding machine.

[0004] The fiber sliver produced in carding machines generally does not have a constant sliver mass at the carding machine exit. This is due, among other things, to material-specific mass fluctuations in the incoming fiber flakes and to the varying degree of contamination in the raw material, which the carding process is intended to remove.

[0005] The integrated draw frame downstream of the carding machine is designed to deposit a sliver with a constant sliver mass into the can changer so that a uniform yarn can be produced in the subsequent process, such as air-jet spinning. Due to space constraints, the integrated draw frame does not have a pre-draft, but only a main drafting zone, which can be formed, for example, by a 2-over-2 or 2-over-3 drafting system. Currently, the draft adjustment is very laborious and manual, and only when significant and new fluctuations in the sliver mass are expected, such as when changing the material batch. In this case, the sliver mass was measured before entering the main drafting zone, and the draft with which a desired sliver mass should enter the can was calculated manually.This calculated factor for adjusting the draft was entered into the carding machine's control system, so that the integrated draw frame was set at least for this batch of material. Regardless, the integrated draw frame could compensate for minor fluctuations in mass, but only within a certain range.

[0006] The object of the invention is the automatic adjustment of the main drafting zone of the integrated draw frame in order to compensate for mass fluctuations of the card sliver within a large adjustment range.

[0007] The invention solves the stated problem by a method having the features specified in claim 1, as well as by a drafting system having the features of claim 6. Advantageous developments of the invention are defined in the dependent claims. The invention relates to a method for controlling the mass of a fiber sliver in an integrated drafting system of a carding machine. The drafting system has an input measuring roller pair upstream of a main drafting zone of the drafting system, as well as an output measuring roller pair downstream of the main drafting zone. During a first calibration, a set sliver mass on the output measuring roller pair forms the reference variable. With the determined incoming sliver mass on the

[0008] The drafting system's draft is adjusted using a pair of input measuring rollers to achieve the desired sliver mass for depositing in the can. As is known from the prior art, the drafting system's draft is adjusted by increasing or decreasing the speed of the drives that drive the drafting system's lower rollers. This data is stored in the carding machine's control system and forms the basis for the subsequent control process.

[0009] In subsequent operation, however, the mass of the sliver at the input measuring roller pair forms the reference variable and the draft of the drafting system the control variable, whereby a change in the mass of the sliver at the input measuring roller pair in the card control system causes a change in the control variable. The size of the change in the

[0010] The manipulated variable in the carding machine's control system is stored as a graph or curve formed by at least two parameters. The main drafting zone is formed by a 2-over-2 drafting system or a 2-over-3 drafting system. The first and second pairs of drafting rollers each have their own drives, which can be controlled independently of one another by the carding machine's control system. To change the draft, the speed of just one drive or both drives can be changed. When the change in draft is described here in general terms, the person skilled in the art knows that the drives are controlled to adjust the speeds of the drafting rollers.

[0011] A first parameter of the graph or curve is formed by the set draft of the drafting system at a given reference value.

[0012] Calibration data is used. At least a second parameter is created by a changed draft with either an increased or decreased mass of the sliver at the input measuring roller pair. A third parameter can be created by a changed draft with a reduced mass of the sliver at the input measuring roller pair, which differs from the second parameter. If an increased sliver mass is used to determine the second parameter, a reduced sliver mass comes into play for the third parameter. The graph is therefore created from at least two parameters or points in a diagram, so that if the mass of the sliver differs, the corresponding draft can be interpolated from these two points. If three parameters are used, a curve can be saved in the card control system that more accurately depicts the change in draft with a different incoming sliver mass.The adjustment becomes even more precise by increasing the number of parameters to, for example, 5, 7, 9, or more. Two parameters have proven sufficiently accurate for automated operation during a batch change on the carding machine, as the time required to calibrate the process is reasonable.

[0013] Because the change in the manipulated variable occurs immediately in the event of a deviation from the reference variable (in operation the strip mass at the input measuring roller pair), small

[0014] Mass fluctuations in the deposited fiber sliver in the can. Alternatively, after a specified dead time, which can be adjusted in the carding machine's control system depending on the fiber sliver delivery speed, the control variable can be changed, which is gentler on the fibers being processed.

[0015] To determine the graph or curve, a sliver mass (FB) at the input measuring roller pair (6a, 6b) is used that can deviate by ±50% from a specified sliver mass (FB) at the input measuring roller pair (6a, 6b). Preferably, this deviation range can cover a very wide range of fluctuations that only very rarely occur in a produced carded sliver.

[0016] The drafting system according to the invention is designed for drawing a single carded fiber sliver, which is produced in a carding machine and feeds into the drafting system without interruption. The drafting system has a pair of input measuring rollers with a sensor for determining the mass of the fiber sliver in the material flow direction. Following this in the material flow direction is exclusively a 2-over-2 or 2-over-3 drafting system with a main drafting zone, which is followed in the material flow direction by a pair of output measuring rollers with a sensor for determining the mass of the fiber sliver. The drafting system is controlled via the carding machine's control system and is designed to operate the method according to one of the preceding claims.

[0017] The drafting system comprises a first pair of drafting rollers and a second pair of drafting rollers, with each pair of drafting rollers being assigned its own controllable drive for adjusting the draft. The drives can be controlled individually or jointly by the carding machine's control system to change the draft.

[0018] Preferably, the pair of output measuring rollers is designed to transport the fiber sliver into the can changer. This keeps the size of the drafting system compact. Further measures improving the invention are described in more detail below, together with the description of a preferred embodiment of the invention, with reference to the figures.

[0019] They show:

[0020] Figure 1: a carding machine with a subsequent can deposit and an integrated

[0021] Route;

[0022] Figure 2: a front view of the essential components of the line according to the invention;

[0023] Figure 3 shows a representation of the back of the track with the

[0024] Drive components.

[0025] The drafting system shown here in Figures 1 to 3 is shown as a 2-over-2 drafting system. However, it can also be designed as a 2-over-3 drafting system. The method and device preclude the use of a pre-drafting zone, since this would require additional control of the pre-draft and the main draft simultaneously, making the control process more complex.

[0026] Figure 1 shows a carding machine K, in which the produced sliver FB is guided over several deflection rollers R to the drawing unit 1. The drawing unit 1 is arranged on top of the can changer W and is integrated into it and is thus a component of the carding machine K. Between the carding machine K and the drawing unit 1, in this embodiment, a storage unit S for the sliver FB is arranged, which is designed to compensate for a difference in the delivery speed of the

[0027] The sliver FB between the card K and the drafting system 1 is to be at least partially compensated. The use or arrangement of the storage S is not relevant for the invention. For a better understanding of the following arrangement of the components, a Cartesian coordinate system is used here, in which the z-direction is the vertical with which the sliver FB enters the drafting system 1. The y-direction corresponds in the following

[0028] Figures of the longitudinal axis of the drafting system rollers, and the x-direction is oriented orthogonally to the longitudinal axis of the drafting system rollers. Essential to the invention is that a single fiber sliver FB enters the drafting system 1 vertically (z-direction) under gravity.

[0029] Figure 2 shows a first front view of the opened drafting system 1 after the hood 20 and the cover flap 3 have been removed. Only a front part of the upper

[0030] Drive housing 4a, which, according to the further figure, extends further behind the arrangement of the rollers and funnels and is not shown here. The fiber sliver FB, not shown here, runs vertically (z-direction) into the first funnel 5 and is detected by the input measuring roller pair 6a, 6b. The funnel 5 is designed to be pivoted upwards in the vertical direction (Z-direction) away from the input measuring roller pair 6a, 6b in order to enable cleaning of the subsequent input measuring roller pair 6a, 6b or to eliminate faulty piecing. The subsequent input measuring roller pair 6a, 6b is designed to detect the deviation of the fiber sliver FB from a predetermined sliver mass and to transmit the measured values ​​to a control system (not shown) and to display them on a screen, which can be the control system of the card K, for example.For this purpose, an input measuring roller 6b is mounted in a stationary, rotatable manner, while a second input measuring roller 6a is mounted displaceably relative to the first input measuring roller 6b. The displacement of the second input measuring roller 6a can be detected, for example, using a voice coil or another sensor, and the change in travel can be converted into a mass deviation. Not further designated, roller cleaners in the form of scrapers can be arranged on both sides of the input measuring roller pair 6a, 6b, with which the surface of the input measuring rollers 6a, 6b is cleaned. The input measuring roller pair 6a, 6b can be designed as grooved / contact rollers or as stepped rollers, or can comprise two smooth rollers. A stripper 16 or another guide element can be arranged below the left measuring roller 6b shown in this view, with which the fiber sliver FB is released from the input measuring roller pair 6a, 6b and guided into the first draw roller pair 7, 8.

[0031] A lever (not shown here) can be used to release a pressure load (not shown) on the movable input measuring roller 6a, allowing it to be moved away from the stationary input measuring roller 6b. This facilitates maintenance and cleaning of the input measuring roller pair 6a, 6b and the upper stretching roller pair 7, 8 located below them.

[0032] The fiber sliver FB continues to travel vertically downwards until it is gripped by the first lower roller 7 and the first upper roller 8. The first lower roller 7 is driven by a first drive 21, which can be designed as a variable-speed drive. These two rollers 7, 8 form the first pair of draw rollers. With a slight offset counter to the x-direction, the fiber sliver FB strikes a pressure bar 13, is guided past it, and reaches the second pair of draw rollers, which is formed by the second lower roller 9 and the second upper roller 10. The draw roller 1 shown here is thus designed as a vertically arranged 2-over-2 draw roller (single-zone draw roller), with two lower rollers 7, 9 and two upper rollers 8, 10.Despite the vertical arrangement of the draw roller pairs in relation to one another, the system refers to upper and lower rollers, comparable to a normal draw roller system with a horizontal material flow direction of the sliver, since the lower rollers have a metallic, corrugated surface and the upper rollers are covered with plastic or rubber. The sliver FB is drawn lengthwise by the first and second draw roller pairs due to different speeds and is guided into the second funnel 14. Also visible are a first and a second cylinder 11a, 12a, with which the upper rollers 8, 10 are pressed at one end against the lower rollers 7, 9 against the x-direction by the pistons of the cylinders 11a, 12a. The second lower roller 9 is driven by a further drive 30, which can be controlled independently of the first drive 21.This means that the two pairs of rollers 7, 8 and 9, 10 are driven independently of each other, which allows the draft in the main drafting area to be adjusted.

[0033] The funnel 14 is designed as a piecing aid and has lateral swirl nozzles along the inner bore through which compressed air flows. This creates a

[0034] Suction is generated, with which the fiber sliver FB is drawn into the funnel and guided to the output measuring roller pair 15a, 15b. The output measuring roller pair 15a, 15b is also designed to detect the deviation of the sliver mass from a predetermined value. A first fixed output measuring roller 15a interacts with a movably mounted second output measuring roller 15b, whose change in distance from the first fixed output measuring roller 15a is converted into a sliver mass deviation by a sensor (not shown), for example in the control system of the carding machine. These values ​​are also transmitted to a control system, for example of the carding machine, which can compare the values ​​with the values ​​of the input measuring roller pair 6a, 6b and display them on a

[0035] The output measuring roller pair 15a, 15b can be designed as a smooth roller pair or as a grooved / touch roller pair or with stepped rollers. Roller cleaners in the form of scrapers can be arranged on both sides of the output measuring roller pair 15a, 15b, with which the surface of the measuring rollers is cleaned. A pressure load (not shown) can be applied to the displaceable

[0036] The output measuring roller 15a can be lifted, allowing it to be moved away from the stationary output measuring roller 15b. This facilitates maintenance and cleaning of the output measuring roller pair 15a, 15b and the storage tube 40 arranged underneath. The lever 36b is shown in Figure 5 in a locked position for the movable output measuring roller 15a.

[0037] After the exit measuring roller pair 15a, 15b, the drawn fiber sliver FB is deposited in a can (not shown) by a known depositing tube 40, which is rotated by a can plate 41, for example, in the shape of a cycloid. A sensor 17 is arranged between the exit measuring roller pair 15a, 15b and the depositing tube 40 and is designed to monitor the entrance or opening of the depositing tube 40 for a possible sliver jam. The signals from the entrance measuring roller pair 6a, 6b and the exit measuring roller pair 15a, 15b can be processed in the control system of the carding machine K or in the control system of the spinning preparation system. The control system can output a signal when an automatic piecing process has been successful. Both measuring roller pairs 6a, 6b; 15a, 15b then generate a uniform signal for the sliver mass.If, after automatic piecing, only the input measuring roller pair 6a, 6b shows a consistent signal, while the output measuring roller pair 15a, 15b shows no signal or a significantly changed signal, this indicates a break in the fiber sliver FB. If there is a deviation in the set fiber sliver mass at the input measuring roller pair 6a, 6b and the output measuring roller pair 15a, 15b, the carding machine control system is designed to actuate the drives 21 and / or 30 to adjust the draft.

[0038] To introduce the fiber sliver FB into the drafting system 1, the card K is operated at a low delivery speed or operating speed, which can be, for example, between 10 m / min and 100 m / min speed of the outgoing fiber sliver.

[0039] The carding speed is preferably between 10 m / min and 50 m / min. The carded fiber web is transferred from the carding doffer, for example, to the downstream cross belt or the take-off rollers and fed into the integrated funnel. The downstream measuring rollers at the carding exit can already detect the sliver mass of the formed fiber sliver FB or the deviation of the sliver mass from a reference, and the associated signal is processed in the carding control system. Upon detecting the sliver mass, the control system of the carding machine K automatically starts the drafting system 1 by driving the drives 21, 30 the input measuring rollers 6a, 6b, the drafting roller pairs 7, 8; 9, 10 and the output measuring roller pairs 15a, 15b. The drafting system 1 is locked, which means that the pneumatic loading of the top rollers 8, 10 is activated.

[0040] At the same time, the drive 30 rotates the can plate 41 of the can changer W. The operator manually removes the fiber sliver FB running out of the card K and, with the hood 2 closed, feeds it through the opening 3a into the upper first funnel 5 of the draw frame 1. The beginning of the fiber sliver FB is detected by the input measuring roller pair 6a, 6b and drawn into the draw frame 1. When the input measuring roller pair 6a, 6b is detected, the associated sensor sends a signal to the control system of the card K, which generates compressed air to create a suction draft at the second funnel 14. The suction draft assists the threading of the fiber sliver FB by the fiber sliver FB being detected and drawn in by the first draw frame roller pair 7, 8.Due to the horizontal offset of the draw roller pairs 7, 8; 9, 10, the fiber sliver FB impacts the side surface of the pressure bar 13 and is guided to the upper gusset of the second draw roller pair 9, 10, where it is gripped and drawn into the second funnel 14 by the suction draft. The rotational movement of the draw roller pairs 7, 8; 9, 10 also generates an air flow within the draw frame 1, which promotes automatic threading. The fiber sliver FB can then be gripped by the output measuring roller pair 15a, 15b and guided into the deposit tube 40 to the already rotating can plate 41. When the fiber sliver is gripped by the output measuring roller pair 15a, 15b, the associated sensor can transmit a signal to the control system of the card K, which initiates the threading of the.

[0041] The fiber sliver is recognized as successfully completed and the introduction of compressed air to the second funnel 14 can be stopped. At the same time, the delivery speed of the card is increased to the operating speed required for the fiber quality without operator intervention. The speed of draw frame 1 and can changer W is also adjusted to the production speed and delivery speed of the card, respectively.

[0042] If the automatic threading is not successful, for example due to a sliver break or a sliver jam, this can be recognized by the fact that either no fiber sliver runs into the can via the delivery tube 40 or the output measuring roller pair 15a, 15b does not send a signal to the control system of the card K. The control system of the card switches off the drafting system 1 if no signal is received within a time of, for example, one to five seconds after detection of the

[0043] When the sensor of the input measuring roller pair 6a, 6b detects a sliver, the output measuring roller pair 15a, 15b sends a signal to the card control system. Alternatively, in the event of a sliver jam or sliver break, the sensor 17 can send a signal to the card control system to abort the automatic threading process. Draw frame 1 and the

[0044] Can changers W are stopped, while simultaneously card K continues to operate at the low delivery speed or operating speed. Sliver thus continues to run slowly but continuously from the card. Draw frame 1 is unlocked, removing the pressure on the top rollers 8, 10. Hood 2 of draw frame 1 is opened, and the sliver residues can be removed. By closing the

[0045] The locking, i.e., the pressure load on the upper rollers 8, 10, takes place in the hood 2 of the draw frame 1. At the same time, the drives 21, 30 start the input measuring rollers 6a, 6b, the draw roller pairs 7, 8; 9, 10, and the output measuring roller pairs 15a, 15b. The fiber sliver FB from the card K can be fed back into the upper funnel 5, and the automatic piecing process starts again.

[0046] During a can change, which is also initiated by the control system of the carding machine K, the compressed air can be introduced to generate a suction draft at the second funnel 14 before a thin spot is created in the fiber sliver FB. After the fiber sliver FB has been torn off at the thin spot, the compressed air continues to be generated until the fiber sliver FB is at least again grasped by the pair of output measuring rollers 15a, 15b. The time for blowing the compressed air into the second funnel 14 before and after the thin spot is created in the fiber sliver FB can be set in the control system of the carding machine K. Instead of the output measuring rollers 15a, 15b, take-off rollers can also be used to discharge the fiber sliver FB into the depositing tube 40.

[0047] For the can change, a thin spot is created in the main drafting zone, i.e. between the draw roller pairs 7, 8; 9, 10, by the two drives 21, 30. The length and intensity of the thin spot are set in the control system of the card K. For this purpose, the drives 21, 30 of the first and second bottom roller 7, 9 are set to a significantly different speed for the time of the upcoming can change, so that a draft occurs between the draw roller pairs 7, 8; 9, 10. The drive of the second bottom roller 9 can be set to a higher speed, or the drive of the first bottom roller 7 can be set to a lower speed. Preferably, the

[0048] The drive of the second lower roller 9 is set at a higher speed so that the sliver storage S and the card do not have to be regulated in the delivery speed during the return run.

[0049] The draft in the drafting system is adjusted at the control system of card K. In a first step, the desired process parameters are calibrated, such as the delivery speed, the sliver mass at the output measuring roller pair 15a, 15b as a reference variable, and the target draft. Since the card's fiber sliver fluctuates in mass, the draft (manipulated variable) in the drafting system must be regulated to achieve the reference variable. The standard adjustment is then carried out during operation of card K and drafting system 1 so that the desired sliver count is produced. The signals from the input measuring roller pair 6a, 6b and the output measuring roller pair 15a, 15b provide feedback to the control system of card K, thus controlling the input.

[0050] If the sliver mass at the input measuring roller pair 6a, 6b deviates, the carding machine's control system must quickly change the draft control variable in order to feed the sliver into the can at the output measuring roller pair 15a, 15b with the constant sliver mass, e.g., 5ktex as the reference value. For this purpose, the control system is calibrated as follows:

[0051] In a second step, the target value for the input measuring roller pair 6a, 6b is continuously and slowly increased up to a defined factor, so that a heavier sliver is presented to the integrated drafting system 1, which can, for example, be 30% higher in sliver mass, i.e. instead of 5 ktex, for example, it is produced with 6.5 ktex in the card.

[0052] The control system of card K also slowly increases the draft control variable in drafting system 1 to compensate for this mass fluctuation. This means that the first drive 21 is controlled for a lower speed for the first bottom roller 7 and / or the second drive 30 is controlled for a higher speed for the second bottom roller 9. If the draft change is too small, a positive deviation would be detected on the output measuring system. If the draft change is too large, a negative deviation would be detected on the output measuring system.

[0053] After the target value of the input measuring roller pair 6a, 6b (e.g. +30%) has been reached, the draft of the drafting system is slowly adjusted until the average output deviation is minimal. The change in draft between the 6.5 ktex sliver mass at the input measuring roller pair 6a, 6b and the 5 ktex sliver mass reached again at the output measuring roller pair 15a, 15b, i.e. the control values ​​of the drives 21 and / or 30, are stored in the control system. The calibration values ​​via the control system and the setting and storage of the draft values ​​when the incoming

[0054] Sliver mass (second step) forms the initial basis for automatic adjustment of the drafting system during operation. These two values ​​are used to store a graph in the carding machine control system, which forms the draft adjustment in the event of a sliver mass deviation at the input measuring roller pair 6a, 6b, without the carding machine control system having to wait for and process the signal from the output measuring roller pair 15a, 15b after the controlled draw frame (passage of the sliver through the drafting system).

[0055] In an optional third step, the target value of the input measuring roller pair 6a, 6b can be continuously and slowly reduced to a defined factor, so that the integrated drafting system 1 is presented by the card K with a sliver that is too light, for example, having a sliver mass of only 3.5 ktex instead of 5 ktex, e.g. -30%. Meanwhile, the drafting system 1 reduces the control variable for draft in the drafting system in order to compensate for this mass fluctuation. Via the control of the card K, the draft in the drafting system 1 is also slowly reduced in order to compensate for this mass fluctuation. This means that the first drive 21 is controlled for a higher speed for the first bottom roller 7 and / or the second

[0056] Drive 30 for a lower speed for the second bottom roller 9. If the change in draft is too small, a negative deviation would be

[0057] Output measuring roller pair 15a, 15b. If the draft change is too large, a positive deviation would occur in the output measuring system. After the target value of the input measuring roller pair 6a, 6b (e.g., -30%) has been reached, the draft control variable of the drafting system is slowly adjusted until the average output deviation is minimal. The change in draft between the 3.5 ktex sliver mass at the input measuring roller pair 6a, 6b and the 5 ktex sliver mass reached again at the output measuring roller pair 15a, 15b, i.e., the control values ​​of drives 21 and / or 30, are stored in the control system.

[0058] The values ​​for the second and third steps can also be swapped, i.e., the setting can be made with a reduced sliver mass in the second step and with an increased sliver mass in the third step. Using the two parameters (first and second step), a linear graph is produced, or using a third parameter (third step), a curve in a diagram, which is stored in the carding machine control system. Based on the graph or the curve, the control system can immediately activate one or both drives 21, 30 based on the deviation of the sliver mass at the input measuring roller pair 6a, 6b in order to achieve the specified sliver mass at the

[0059] Output measuring roller pair 15a, 15b. The curve thus corresponds to the manipulated variable for controlling the control deviation from a reference variable. The distortion change, which occurred slowly during the second and third calibration steps, can now be implemented directly and immediately.

[0060] This means that the controller immediately changes the draft control variable by a stored value or factor in order to deposit the target strip mass (reference variable) in the can on the short control path between the input measuring roller pair 6a, 6b and the output measuring roller pair 15a, 15b. The parameterization of the draft controller is now optimized based on the at least two operating points. Instead of the at least two operating points, several operating points, for example, 3, 5, 7, or 9, can be determined in order to more accurately determine the curve of the reference variable and precisely interpolate any possible deviations.

[0061] The change in the draft of the drafting system via the control of the card when the sliver mass at the input measuring roller pair 6a, 6b changes can take place directly and immediately, or relatively slowly after a predetermined dead time, so that the deviation at the output measuring roller pair 15a, 15b always remains small and does not endanger the customer's quality requirements.

[0062] Figure 3 shows the rear of the draw frame according to the invention with the drive concept. The upper drive housing 4a is completely separate from the lower drive housing 4b and can be moved along the guide plate 24 by means of an adjusting element 23 (not shown), so that the nip line spacing L1, L2 can be adjusted without individually adjusting the draw frame rollers 7, 8, 9, 10. Both the upper and lower drive housings 4a, 4b each have a separate, independent drive, which is not affected by the adjustment of the nip line spacing. The fact that all drive components are arranged on the rear of the draw frame results in a freely accessible front side, which offers sufficient space for maintenance or cleaning. Disassembly of drive components or their adjustment is therefore not necessary.In addition, the bearing concept of the top rollers 7, 9, in which the front cylinders 11b, 12b are arranged in opposite directions to the rear cylinders 11a, 12b, facilitates the disassembly of the top rollers 7, 9. Once the top rollers 7, 9 are disassembled, there is ample free space to the remaining drafting system components for maintenance and cleaning.

[0063] The upper drive housing 4a has a first drive 21, which drives the second adjustable input measuring roller 6b and the first lower roller 7 by means of a first belt 26. A second belt 28 drives the first input measuring roller 6a from the driven second input measuring roller 6b and is deflected by a deflection roller 29. The drive directions of the first and second input measuring rollers 6a, 6b are opposite, so that the fiber sliver FB is transported vertically downwards by the input measuring rollers 6a, 6b. A sensor 27 is arranged on the stationary input measuring roller 6b and is designed to determine the concentricity of this roller 6b and to compensate for any possible non-concentricity by measurement. This allows monitoring of the measurement accuracy of the determined sliver mass deviation. The sensor 27 can be designed, for example, as a voice coil or piezo element.The first upper roller 8 is pressed against the first lower roller 7 by the pressure of the cylinders 11a, 11b on the roller bearings 8.4, 8.5 with the roller cover 8.1, thereby driving it frictionally. The separation of the drives into an upper drive housing 4a with the first pair of stretching rollers 7, 8 and a lower drive housing 4b with the two pairs of stretching rollers 9, 10 enables the nip line spacing L1, L2 to be adjusted, while simultaneously allowing the speed of the lower rollers 7, 9 and the load pressure of the upper rollers 8, 10 to be controlled separately. At the same time, the driven measuring rollers 6b, 15b are decoupled from each other in terms of drive technology, eliminating the need for crossed belts.

[0064] The lower drive housing 4b also has its own second drive 30, which is also used to drive the can plate 41. A first belt 31 drives the second lower roller 9 and the fixed output measuring roller 15a. The adjustable output measuring roller 15b is driven by the fixed output measuring roller 15a via a second belt 32. The second belt 32 is deflected by the deflection roller 34, so that both output measuring rollers 15a, 15b are driven in opposite directions and pull the fiber sliver FB between them and transport it into the depositing tube 40. A tensioning element 35 ensures the necessary belt tension. The second drive 30 drives a third belt 33, which sets the can plate 41 in rotation. The drives 21, 30 can be designed as servo drives, which eliminates the need to change gears when changing the draw field width or draft depending on the fibers to be processed.Reference symbol.

[0065] 1 drafting system

[0066] 2 hood

[0067] 2a, 2b wings

[0068] 3 Cover flap

[0069] 3a Opening

[0070] 4a, 4b drive housing

[0071] 5 first funnel

[0072] 6, 6a, 6b Input measuring roller pair

[0073] 7 first lower roller

[0074] 8 first top roller

[0075] 9 second lower roller

[0076] 10 second top roller

[0077] 11a first cylinder

[0078] 12a second cylinder

[0079] 13 compression rod

[0080] 14 second funnel

[0081] 15a, 15b Output measuring roller pair

[0082] 16 scrapers

[0083] 17 Sensor

[0084] 21 first drive

[0085] 23 Control element

[0086] 24 Guide plate

[0087] 26 first belt

[0088] 27 Sensor

[0089] 28 second belt

[0090] 29 pulley

[0091] 30 second drive

[0092] 31 first belt

[0093] 32 second belt

[0094] 33 third belt

[0095] 34 pulley

[0096] 35 clamping element

[0097] 36b lever

[0098] 37 pipe

[0099] 40 storage tube

[0100] 41 jug plates

[0101] A filing

[0102] FB fiber ribbon

[0103] K Card

[0104] R pulley S storage

[0105] V Offset

[0106] W Can changer x, y, z direction

Claims

Patent claims 1. Method for controlling the mass of a fiber sliver (FB) in an integrated drafting system (1) of a card (K), comprising an input measuring roller pair (6a, 6b) upstream of a main drafting zone of the drafting system, and an output measuring roller pair (15a, 15b) downstream of the main drafting zone, wherein the mass of the fiber sliver (FB) at the input measuring roller pair (6a, 6b) forms the reference variable and the draft of the drafting system forms the manipulated variable, wherein a change in the mass of the fiber sliver (FB) at the input measuring roller pair (6a, 6b) causes a change in the manipulated variable in the control system of the card (K), and the magnitude of the change in the manipulated variable is stored in the control system of the card (K) by a graph or curve which is formed by at least two parameters.

2. Method according to claim 1, characterized in that a first parameter of the graph or the curve is formed by the set draft of the drafting system (1) at a predetermined reference variable, and that at least a second parameter is formed by a changed draft with increased or reduced mass of the fiber sliver (FB) at the input measuring roller pair (6a, 6b).

3. Method according to claim 2, characterized in that, and a third parameter is formed by a changed draft with a changed mass of the fiber sliver (FB) at the input measuring roller pair (6a, 6b), which differs from the mass of the fiber sliver (FB) in the second parameter.

4. Method according to claim 1, characterized in that the change in the manipulated variable takes place immediately in the event of a deviation from the reference variable, or after a predetermined time which can be set in the control of the card (K) as a function of the delivery speed.

5. Method according to claim 2, characterized in that for determining the graph or the curve, the mass of the fiber sliver (FB) at the input measuring roller pair (6a, 6b) can deviate by ±50% from a predetermined mass of the fiber sliver (FB) at the input measuring roller pair (6a, 6b), preferably by ±30%.

6. Drafting device for drawing a single carded fiber sliver (FB), wherein the fiber sliver is produced in a card (K) and runs into the drafting device (1) without interruption, comprising in the material flow direction an input measuring roller pair (6a, 6b) with a sensor for determining the mass of the fiber sliver (FB), downstream in the material flow direction exclusively comprising a 2-over-2 or 2-over-3 drafting device with a main drafting field and a downstream in the material flow direction Output measuring roller pair (15a, 15b) with a sensor for determining the mass of the fiber sliver (FB), wherein the drafting system (1) is controlled via the control of the card (K) and is designed to operate the method according to one of claims 1 to 5.

7. Drafting system according to claim 6, characterized in that the drafting system has a first drafting roller pair (7, 8) and a second drafting roller pair (9, 10), wherein each drafting roller pair (7, 8; 9, 10) is assigned its own controllable drive for adjusting the draft.

8. Drafting system according to claim 6, characterized in that the output measuring roller pair (15a, 15b) is designed to guide the fiber sliver into the To transport can changers.

9. Drafting system according to claim 6, characterized in that the drafting system has no pre-drafting field.

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