Method and device for separating a fiber strip during can exchange in a stretch

Description

1 / 21 METHOD AND APPARATUS FOR SEPARATING A FIBER STRIP DURING CAN CHANGES IN A STRETCHING PROCESS

[0001] The present invention relates to a method and device for separating a single carded fiber sliver during can change in a drawing machine, wherein the fiber sliver is generated in a carding machine and enters without interruption into the drawing system disposed at the top of the can changer associated with the carding machine, wherein the fiber sliver is guided vertically through a main delay field of the drawing machine to a funnel and then to a pair of take-off rollers that guide the fiber sliver through a base tube of a can plate into a can.

[0002] After drawing, the fiber slivers are usually deposited into cans, which must be changed when the can is full. For this, the fiber sliver needs to be separated, for which several methods are known. This can be done by generating a thin point or by using a separation element that tears the fiber sliver. According to the state of the art, the machine that produces the fiber sliver and / or the drawing and / or the can base are briefly stopped. Increasing the production speed during the generation or processing of the fiber sliver results in undesirable quality differences in the fiber sliver.

[0003] Document DE 19548232 A1 describes a device in which a fine spot is generated in the drawing system by increasing the delay in the main delay field. The section of fiber sliver with the fine spot is then conveyed through the sliver channel by means of calender rolls until the fine spot reaches the exit opening of the sliver channel. At this point, the machine is stopped or the delivery speed is significantly reduced to eject the full can, so that the fine spot on the edge of the sliver exit opening breaks.

[0004] Document DE102004017441 B4 discloses a stretching process in which a thin point is created between the stretching system and the take-off rollers, through which a fleece nozzle supports the sliver separation process. This Petition 870250089324, dated 10 / 01 / 2025, page 10 / 104 Document 2 / 21 reveals different types of fine point generation, i.e., with different roller speeds in the main delay, or the elevation of individual rollers upstream, or between the rollers of the drawing system and the take-off rollers. The can changeover then occurs while the machine is stopped or running at low speed, which causes the fine point at the exit opening of the tape channel to be further delayed and tear. The end of the tape furthest from the machine hangs on the edge of the full can, for example, while the end of the tape closest to the machine may be deposited on the empty can that is being transported next.

[0005] In this state of the art, the fiber sliver delivery speed needs to be interrupted or reduced so significantly that this is noticeable in the quality of the fiber sliver produced. The carding machine is lowered and the drafting system is interrupted for a short period until the can is changed.

[0006] The objective of the invention is to eliminate these disadvantages and achieve high-speed tape can replacement.

[0007] The invention solves the objective defined by a method with the characteristics specified in claim 1 and by a drawing system with the characteristics of claim 6. Other advantageous embodiments of the invention are defined in the dependent claims.

[0008] The invention relates to a method for separating a single carded fiber sliver during a can changer in a drawing machine, wherein the fiber sliver is generated in a carding machine and enters without interruption into the drawing system disposed at the top of the can changer associated with the carding machine, the fiber sliver being guided vertically through a main delay field of the drawing machine to a funnel and then to a pair of take-off rollers. In contrast to the prior art, the take-off rollers guide the fiber sliver into a base tube of a continuously rotating can plate in a can.

[0009] The method according to the invention has the following steps: Petition 870250089324, dated 10 / 01 / 2025, p. 11 / 104 3 / 21 - Reducing the speed of the can plate to a fiber tape delivery speed of 50 m / min to 300 m / min, - introduction of compressed air into the funnel to generate a suction current in the fiber tape, - creation of a thin point on the fiber tape, in the main delay field of the drawing system, - routing the fiber tape with the fine point through the funnel subjected to compressed air, via the removal rollers, into the base tube of the tin plate, - triggering the can changer and therefore the separation of the fiber sliver as soon as the fine point of the fiber sliver has reached the exit of the rotating can plate, - introduction of the fiber sliver into the empty can and operation of the carding machine with the drafting system and the can changer at production speed.

[0010] The fine point can be made as fine as desired using this method, i.e., until complete separation of the fiber tape, as the second funnel also sucks up the new fiber tape start and transports it to the take-off rollers, in this case, the pair of output measuring rollers. This can also be used to fill the new can. However, to reliably achieve the goal of separating the fiber tape without stopping the can plate, it needs to be at least so fine that the fiber bond is no longer sufficient to pull the fiber tape from the replacement can after the can change, when the fine point is suspended between the cans. Instead, the rotation of this new can, which has just been replaced, and the resulting movement relative to the filled can must overcome the minimal residual tape adhesion and achieve separation.In the prior art, it is always necessary to generate a greater opposing force, for example, through the wrapper at the exit of the can plate or through a separating element, to separate the FB fiber tape. Otherwise, the FB fiber tape would wrap around the replacement can during its rotation. In contrast to the prior art, the can plate can continue rotating continuously and does not need to be stopped, which increases efficiency. Petition 870250089324, dated 10 / 01 / 2025, page 12 / 104 4 / 21 significantly improves the quality of the fiber sliver, as the upstream carding speed does not need to be significantly reduced. Productivity also increases, as can changes can occur at a fiber sliver delivery speed of up to 300 m / min.

[0011] Preferably, the fine spot can be generated with a length of 20 mm to 200 mm, preferably with a length of 50 mm. Depending on the delivery speed, the fine spot length is preferably kept short to maintain the quality of the fiber sliver. Advantageously, the fine spot length can be kept short enough to occur within the clamping length of the drawing system, which has a positive effect on the quality of the fiber sliver with a high ratio of short fibers.

[0012] The mass of the fiber tape at the thin point can be reduced from 60% to 100% of the original tape mass, preferably 80% of the original tape mass. Thus, changing cans is perfectly sufficient to separate the fiber tape without stopping the can plate or other auxiliary means.

[0013] The main delay field is formed by a first pair of stretching rolls in the material transport direction and a second subsequent pair of stretching rolls, where the thin spot on the fiber sliver is generated by increasing the speed of the second pair of stretching rolls. Changing or increasing the speed of the second pair of stretching rolls has the least influence, in the short term, on the output of the carding machine and the upstream accumulator.

[0014] Alternatively, the fine point can be achieved by reducing the speed of the first pair of stretching rolls. The associated drive is designed as an adjustable drive and has the advantage of allowing the drive of the smallest masses during fine point generation.

[0015] The introduction of compressed air during a can change in the second hopper can occur for a predetermined time before, during, and after the generation of a thin point on the fiber sliver. The size of the predetermined time can be entered into the carding machine's control unit. This prevents the sliver from starting. Petition 870250089324, dated 10 / 01 / 2025, page 13 / 104 5 / 21 of the resulting fiber accumulates within the drawing system after the fiber sliver is separated.

[0016] The drawing system according to the invention is designed to draw a single carded fiber sliver, wherein the fiber sliver is generated in a carding machine and introduced into the drawing system without interruption, which is disposed at the top of the can changer associated with the carding machine. The drawing system has a first upper hopper, followed, in the direction of material flow, by a pair of inlet measuring rollers with a sensor, followed, in the direction of material flow, by a vertically arranged drawing system with a main delay field and a second hopper, disposed downstream in the direction of material flow, designed to generate a suction current within the drawing system by means of the introduction of compressed air, and followed by a pair of rollers designed to draw the fiber sliver into the base tube of a continuously rotating can plate.The vertical arrangement of the stretching system components, combined with the suction current within the stretching system, not only allows for automatic splicing with the compartment closed, but also the generation of a thin spot to separate the fiber tape during can changes without the need to stop the can plate. Even if the fiber tape tears or the thin spot is reduced by 100% of the fiber tape mass, the newly separated fiber tape is guaranteed to pass through all the stretching system components independently. The can can be replaced while the can plate rotates at a delivery speed of up to 300 m / min.

[0017] The second pair of stretch rolls may be arranged with a horizontal offset relative to the first pair of stretch rolls. To guide the fiber tape from the attachment point of the upper pair of stretch rolls to the attachment point of the lower pair of stretch rolls, a pressure bar may be arranged below the first pair of stretch rolls, so that the fiber tape is guided perpendicularly from a convex surface of the pressure bar to the upper reinforcement of the second pair of rolls. Petition 870250089324, dated 10 / 01 / 2025, p. 14 / 104 6 / 21 stretching. The arrangement of the pressure bar with the pairs of stretching rollers, which have a horizontal displacement, not only facilitates automatic insertion, but also allows for better processing of short fibers, for example, from recycled fabrics.

[0018] The fact that the pair of rollers for extracting the fiber sliver into the base tube can be designed as a pair of output measuring rollers, on the one hand, reduces the overall height of the drafting system and, on the other hand, the drafting system can be used as a regulated drafting system in conjunction with the pair of input measuring rollers. For this purpose, the pair of output measuring rollers can have a sensor whose signals are transmitted to the carding machine control unit. With the sensor signals, automatic splicing and can changing can be stored in the carding machine control system as successfully completed, so that the carding machine delivery speed automatically increases.

[0019] Preferably, a sensor can monitor the fiber sliver entering the base tube for sliver breakage or jamming. This means that the drafting system operation can be interrupted by the carding control system in the event of sliver breakage or jamming, and the carding machine can be unloaded at operating speed. The measuring sensor on the take-off rolls or the pair of output measuring rolls is designed to detect sliver mass fluctuations and sliver breakage. The light barrier sensor after the take-off rolls or the pair of output measuring rolls is designed to detect sliver jamming if, for example, the fiber sliver is not fed into the base tube.

[0020] Other measures that improve the invention are shown in more detail below, together with the description of a preferred exemplary embodiment of the invention with reference to the figures.

[0021] Shown: In Figure 1: a carding machine with a subsequent tin base and an integrated stretch; Petition 870250089324, dated 10 / 01 / 2025, page 15 / 104 7 / 21 In Figures 2a and 2b: a perspective illustration of the closed and open compartment; In Figure 3: a front view of the main components of the stretching mechanism according to the invention; In Figures 4a, 4b: two illustrations of the stretching roller pairs with the pressure bar with different stretching field widths; Figure 5 shows an illustration of the rear of the stretcher with the drive components.

[0022] The drawing system shown in Figures 1 to 5 is represented only as an example of a 2-over-2 drawing system. The method described here for generating a thin spot can be performed in the main delay field of any drawing system (e.g., 3-over-3 or 4-over-3), provided that the fiber strip is drawn in the vertical flow direction of the material and a splicing aid is placed immediately after the main delay field.

[0023] Figure 1 shows a carding machine K in which the produced fiber sliver FB is guided to the stretching system 1 by means of several deflection rollers R. The stretching system 1 is located on top of the can changer W and integrated into it and is therefore a component of the carding machine K. In this exemplary embodiment, an accumulator S for the fiber sliver FB is arranged between the carding machine K and the stretching system 1, which is designed to compensate, at least partially, for a difference in the delivery speed of the fiber sliver FB between the carding machine K and the stretching system 1. The use or arrangement of the accumulator S is not relevant to the invention. For better understanding of the arrangement of the components below, a Cartesian coordinate system is used in this document, in which the z direction is the vertical line with which the fiber sliver FB enters the stretching system 1.In the following figures, the y-direction corresponds to the longitudinal axis of the rollers of the stretching system, and the x-direction is aligned orthogonally to the axis. Petition 870250089324, dated 10 / 01 / 2025, p. 16 / 104 8 / 21 longitudinal of the stretching system rolls. It is essential to the invention that a single FB fiber tape runs vertically (z direction) with gravity into the stretching system 1.

[0024] Figures 2a and 2b show the closed and open cover 2 of the stretching system 1 according to the invention, which comprises wings 2a, 2b on a front side that can be opened horizontally so that the stretching system is accessible for maintenance work. The wings 2a, 2b are articulatedly attached to the cover 2 by means of hinges. Also disposed on the cover 2 is a hinged cover flap 3 with an opening 3a. The cover flap 3 is integrated into the wings 2a, 2b so that the wings 2a, 2b have a corresponding recess for the contour of the cover flap 3. A deflection roller R is disposed on the cover flap 3, by means of which the fiber tape FB can be deflected and inserted into the opening 3a of the cover flap 3 into the first upper funnel 5. A tube 37 is located on top of cover 2, into which a duct can be placed for connection to the exhaust air from the wiring preparation.Dust and unprocessed fiber material can be removed through tube 37. Stretching 1 is arranged on top of a can changer W, with a recessed base A at the top. Base A is designed so that the upper rollers 7, 8 of stretching system 1 can be lowered during maintenance or cleaning. In contrast to the prior art, no processing or fiber guide parts are arranged on the inside of wings 2a, 2b. The cover flap 3 and wings 2a, 2b can completely close the cover 2 – except for the opening 3a – by means of magnetic latches detectable by sensors, so that when the cover 2 is opened during operation, the carding machine control unit interrupts stretching system 1.

[0025] Figure 3 shows a first front view of the open stretch system 1 after the cover 2 and the cover flap 3 have been removed. Only a front part of the upper drive compartment 4a can be seen, Petition 870250089324, dated 10 / 01 / 2025, page 17 / 104 9 / 21 which, according to the other figures, extends further back from the arrangement of the rollers and funnels, and is not shown here. The fiber tape FB, not shown here, runs vertically (z direction) into the first funnel 5 and is detected by the pair of input measuring rollers 6a, 6b. Funnel 5 is designed to be hinged upwards in the vertical direction (z direction), away from the pair of input measuring rollers 6a, 6b, in order to allow cleaning of the next pair of input measuring rollers 6a, 6b or to isolate defective splices. The next pair of input measuring rollers 6a, 6b is designed to detect the deviation of the fiber tape FB from a predetermined tape mass and to feed the measured values ​​to a control unit, not shown, and display them on a screen which, for example, could be the control unit of the carding machine K.For this purpose, an input measuring roller 6b is mounted rotatably in a stationary position, while a second input measuring roller 6a is mounted so as to be movable relative to the first input measuring roller 6b. The displacement of the second input measuring roller 6a can be detected using, for example, a plunger coil or other sensor, and the change in path can be converted into a mass deviation. Roller cleaners in the form of scrapers can be arranged on both sides – not shown in more detail – of the pair of input measuring rollers 6a, 6b with which the surface of the input measuring rollers 6a, 6b is cleaned. The pair of input measuring rollers 6a, 6b can be designed as grooved / tactile rollers or as stepped rollers, or it can include two smooth rollers.Below the measuring roller 6b – shown on the left in this view – a stripper 16 or other guide element may be disposed, with which the fiber tape FB is released from the pair of input measuring rollers 6a, 6b and guided to the first pair of stretching rollers 7, 8. A lever, not shown here, may be used to lift a pressure load, not shown, over the movable input measuring roller 6a, with which it may be moved away from the stationary input measuring roller 6b. This allows for the maintenance and cleaning of the pair of input measuring rollers 6a, 6b and the pair of stretching rollers. Petition 870250089324, dated 10 / 01 / 2025, p. 18 / 104 10 / 21 7, 8 superior ones arranged below them, are facilitated.

[0026] The fiber sliver FB continues to travel vertically downwards until it is captured by the first lower roller 7 and the first upper roller 8. These two rollers 7, 8 form the first pair of stretching rollers. With a slight displacement relative to the x direction, the fiber sliver FB reaches a pressure bar 13, is guided by it and arrives at the second pair of stretching rollers, formed by the second lower roller 9 and the second upper roller 10. The stretching system 1, according to the invention, is designed as a vertically arranged 2-over-2 stretching system (single-zone stretching system), with two lower rollers 7, 9 and two upper rollers 8, 10.Despite the vertical arrangement of the stretching roller pairs relative to each other, the upper and lower rollers are referred to here in a manner comparable to a normal stretching system with horizontal material flow direction of the fiber tape, as the lower rollers have a corrugated metal surface and the upper rollers are fitted with a plastic or rubber cover. The fiber tape FB is stretched lengthwise by the first and second stretching roller pairs due to different speeds and guided into the second hopper 14. A first and second cylinders 11a, 12a are also visible, with which the upper rollers 8, 10 are pressed against the lower rollers 7, 9 at one end with the pistons of cylinders 11a, 12a against the x direction.

[0027] Funnel 14 is designed as a splicing aid and comprises lateral rotating nozzles along the inner orifice through which compressed air flows. This creates a suction current at the funnel opening, whereby the FB fiber tape is pulled into the funnel and guided to the pair of output measuring rollers 15a, 15b. The pair of output measuring rollers 15a, 15b is also designed to detect the deviation of the tape mass from a predetermined value. A first fixed output measuring roller 15a interacts with a second movable output measuring roller 15b, whose change in distance from the first fixed output measuring roller 15a is converted into a mass deviation. Petition 870250089324, dated 10 / 01 / 2025, p. 19 / 104 11 / 21 of the tape by a sensor not shown, for example, in the carding machine control unit. These values ​​are also transmitted to a control unit, 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 screen. The output measuring roller pair 15a, 15b can be designed as a pair of smooth rollers or as a pair of grooved / tactile rollers or with stepped rollers. Roller cleaners in the form of scrapers can be arranged on both sides – not shown in more detail – of the output measuring roller pair 15a, 15b with which the surface of the measuring rollers is cleaned. A lever 36b can be used to lift a pressure load, not shown, over the movable output measuring roller 15a, with which it can be moved away from the stationary output measuring roller 15b.This facilitates maintenance and cleaning of the pair of output measuring rollers 15a, 15b, as well as the base tube 40 located below them. Lever 36b is shown in Figure 5 in a locked position for the movable output measuring roller 15a.

[0028] After the pair of output measuring rollers 15a, 15b, the stretched fiber tape FB is placed in a can, not shown, by means of a known base tube 40, which is twisted by a can plate 41, for example, in the shape of a cycloid. A sensor 17 is disposed between the pair of output measuring rollers 15a, 15b and the base tube 40, designed to monitor the entry or opening of the base tube 40 for possible tape jamming.

[0029] The signals from the input measuring roller pair 6a, 6b and the output measuring roller pair 15a, 15b can be processed in the K carding machine control unit or the spinning preparation system control unit. The control unit can output a signal if the automatic splicing process is successful. Both measuring roller pairs 6a, 6b; 15a, 15b generate a uniform signal for the tape mass. If, after automatic splicing, only the input measuring roller pair 6a, 6b shows a uniform signal, but the output measuring roller pair 15a, 15b shows no signal or shows a significantly altered signal, this is a Petition 870250089324, dated 10 / 01 / 2025, page 20 / 104 12 / 21 indicates that the FB fiber tape has broken.

[0030] To introduce the FB fiber sliver into the drawing system 1, the carding machine K is operated at a low delivery speed or operating speed, which can be between 10 m / min and 100 m / min of the fiber sliver output speed, for example. The carding machine speed is preferably from 10 m / min to 50 m / min. The stack of carded fibers is transferred from the carding machine extractor, for example, to the next cross sliver or to the take-off rolls and inserted into the integrated hopper. The measuring rolls following the carding machine output can already detect the mass of the FB fiber sliver formed or the deviation of the fiber sliver mass from a reference, and the associated signal is processed in the carding machine control system.When the sliver mass is detected, the K carding machine control system automatically starts the stretching system 1 by means of drives 21, 30 which drive the input measuring rollers 6a, 6b, the stretching roller pairs 7, 8; 9, 10 and the output measuring roller pairs 15a, 15b. The stretching system 1 is then locked, meaning that the pneumatic load on the upper rollers 8, 10 is activated. At the same time, drive 30 causes the can plate 41 of the can changer W to rotate. The operator manually removes the FB fiber sliver coming out of the K card and inserts it, through opening 3a, via the closed cover 2, into the first upper funnel 5 of the draw 1. The beginning of the FB fiber sliver is captured by the pair of input measuring rollers 6a, 6b and inserted into the draw 1.When the pair of input measuring rollers 6a, 6b is detected, the associated sensor sends a signal to the carding machine control system K, which generates compressed air to create a suction current in the second hopper 14. The suction current supports the insertion of the fiber sliver FB, where the fiber sliver FB is captured and pulled by the first pair of stretching rollers 7, 8. Due to the horizontal displacement of the stretching roller pairs 7, 8; 9, 10, the fiber sliver FB collides with the lateral surface of the pressure bar 13 and is guided to the upper reinforcement of the second pair of stretching rollers 9, 10, captured by the same and pulled into the second hopper 14 by the suction current. The rotary movement of the pairs of... Petition 870250089324, dated 10 / 01 / 2025, p. 21 / 104 13 / 21 stretching rollers 7, 8; 9, 10 also generate an airflow within the stretching system 1, which facilitates automatic insertion. Then, the fiber sliver FB can be collected by the pair of output measuring rollers 15a, 15b and guided into the base tube 40 to the can plate 41 already rotating. When the fiber sliver is collected by the pair of output measuring rollers 15a, 15b, the associated sensor can transmit a signal to the carding machine control system K, which recognizes that the fiber sliver insertion has been successfully completed and can stop the introduction of compressed air into the second hopper 14. At the same time, the carding machine delivery speed is increased to the operational speed required for fiber quality, without the need for operator intervention. The speed of stretching 1 and the can changer W is also adjusted to the production speed or the carding machine delivery speed.

[0031] If automatic insertion is unsuccessful, for example due to a tape break or jam, this can be recognized by the fact that no fiber tape enters the can through base tube 40 or the pair of output measuring rollers 15a, 15b does not send a signal to the carding machine control unit K. The carding machine control system shuts down the drawing system 1 if the pair of output measuring rollers 15a, 15b does not send a signal to the carding machine control system within a period of, for example, one to five seconds after the fiber tape has been captured by the sensor of the pair of input measuring rollers 6a, 6b. Alternatively, sensor 17 may send a signal to cancel the automatic insertion process to the carding machine control system in the event of tape jam or breakage. Stretching unit 1 and can changer W are stopped, while carding machine K continues to operate at delivery speed or low operating speed.This means that the fiber sliver continues to come out of the carder slowly but continuously. Stretch 1 is unlocked, so the pressure load on the upper cylinders 8 and 10 is canceled. Cover 2 of stretch 1 is opened and the remnants of the sliver can be removed. Closing cover 2 of stretch 1 results in locking, i.e., the application of pressure load on the upper cylinders 8 and 10. Petition 870250089324, dated 10 / 01 / 2025, p. 22 / 104 14 / 21 At the same time, drives 21 and 30 start the input measuring rollers 6a and 6b, the stretching roller pairs 7, 8, and 9, and the output measuring roller pairs 15a and 15b. The FB fiber tape from the K carding machine can be fed back into the upper hopper 5, and the automatic splicing process begins again.

[0032] During a can change, which is also initiated by the K carding machine control system, compressed air to generate a suction current can be introduced into the second hopper 14 before a thin spot is generated in the FB fiber sliver. After the FB fiber sliver is broken at the thin spot, compressed air continues to be generated until the FB fiber sliver is at least picked up again by the pair of output measuring rollers 15a, 15b. The time to blow compressed air into the second hopper 14 before and after the generation of the thin spot in the FB fiber sliver can be set in the K carding machine control system. Instead of the output measuring rollers 15a, 15b, withdrawal rollers can also be used to remove the FB fiber sliver into the base tube 40.

[0033] For can change, a thin spot is created in the main delay field, i.e., between the pairs of stretching rollers 7, 8; 9, 10, by the two drives 21, 30.The length and intensity of the fine point are defined in the K carding machine control system. To achieve this, the drives 21, 30 of the first and second lower rolls 7, 9 are set to significantly different speeds for the next can change, so that a delay occurs between the pairs of stretching rolls 7, 8; 9, 10. The drive of the second lower roll 9 can be set to a higher speed, or the drive of the first lower roll 7 can be set to a lower speed. Preferably, the drive of the second lower roll 9 is set to a higher speed so that the delivery speed of the sliver accumulator S and the carding machine does not need to be regulated during the return operation. The resulting delay is preferably set to a length of 50 mm, so that the sliver mass is reduced by 80% at the fine point. The splicing aid (second funnel 14) is arranged between the pair of rolls. Petition 870250089324, dated 10 / 01 / 2025, p. 23 / 104 The stretching rollers 9, 10 and the pair of output measuring rollers 15a, 15b, which assume the function of withdrawal rollers in this document, ensure that the FB fiber tape with the thin point is presented to the pair of output measuring rollers 15a, 15b for further transport and guided into the base tube 40 of the can plate 41. Thus, if the thin point is at the output of the can plate 41, the can change is triggered and the FB fiber tape with the most pronounced thin point breaks automatically as it is removed from the full can. This means that the can plate 41 no longer needs to be stopped and the can change process can be carried out at significantly higher delivery speeds.In contrast to the prior art, both the K carding machine and the drafting system 1 and the can changer W can continue to operate at a fiber sliver delivery speed of 50 m / min to 300 m / min, which corresponds to approximately 50% of the K carding machine's production capacity at that moment of can change. The fiber sliver delivery speed is preferably between 100 m / min and 300 m / min. The splicing aid, which is designed as a second hopper 14 subjected to compressed air, reliably guides the fine point to the pair of output measuring rolls 15a, 15b or to the take-off rolls.

[0034] The fine point can be made as fine as desired by this method, i.e., until complete separation of the FB fiber tape, as the second funnel 14 also sucks up the new fiber tape start and transports it to the withdrawal rollers, in this case, the pair of output measuring rollers 15a, 15b. This can also be used to fill the new can. However, to reliably achieve the goal of separating the FB fiber tape without stopping the can plate 41, it needs to be at least so fine that the fiber bond is no longer sufficient to pull the FB fiber tape from the replacement can after the can change, when the fine point is suspended between the cans. Instead, the rotation of this new can, which has just been replaced, and the resulting movement relative to the filled can must overcome the minimal residual tape adhesion and achieve separation. In the state of the art, it is always Petition 870250089324, dated 10 / 01 / 2025, page 24 / 104 16 / 21 It is necessary to generate a greater counterforce, for example, through the wrapper at the can plate outlet or through a separating element, to separate the FB fiber tape. Otherwise, the FB fiber tape would wrap around the replacement can during its rotation.

[0035] Tests have shown that, with the resulting delay, which reduces the tape mass at the fine point by between 60% and 100%, it is possible to obtain a fiber tape delivery speed of up to 300 m / min by changing cans. The fine point can be adjusted to a length of 20 mm to 200 mm. The fine point is preferably set to a length of 50 mm. When the FB fiber tape is completely separated, preferably until the fine point is about 80% of the fiber tape mass, the vertical arrangement of the stretching system and the compact arrangement between the stretching system, the second hopper 14 and the pair of output measuring rollers 15a, 15b are advantageous for guiding the FB fiber tape at high delivery speed by changing cans.

[0036] Figure 4a and Figure 4b show the arrangement of rollers 7, 8, 9, 10 of the stretching system in relation to each other in combination with the pressure bar 13. The warp field between the fixing points P1 and P2 is displaced from the vertical by dimension V against the x direction. The value of V can be between 5 mm and 12 mm. In the first pair of stretching rollers 7, 8, the first upper roller 8 is arranged vertically displaced in the z direction, below the first lower roller 7. The second upper roller 10 is also arranged vertically displaced in the z direction, below the second lower roller 9. Due to the displacement V of rollers 7, 8; 9, 10 upper to lower of the stretching system, the pressure bar 13 is arranged between the first and second upper rollers 8, 10, so that the fiber tape FB is deflected by the pressure bar 13 to the second fixing point P2.The pressure bar 13 is stationary and positioned at a distance from the first pair of stretching rollers 7, 8 and consists of a rectangular or square base body, on whose outer surface a convex contour is positioned. The convex contour can be shaped as a semicircle or as a circular segment. Petition 870250089324, dated 10 / 01 / 2025, page 25 / 104 17 / 21 comprising a continuous radius. Pressure bar 13 can be used to increase the distance of the clamping line during the processing of short fibers from L1, with 35 mm (Figure 4a), to L2, with 75 mm (Figure 4b). In its longitudinal direction, pressure bar 13 is inclined from the vertical in a horizontal direction by an angle α. The angle α can be between 40° and 60°, preferably between 50° and 55°. The center line of pressure bar 13 can cut the center point of the first upper roll 8. The convex surface of pressure bar 13, which contacts the fiber sliver FB and guides the fibers, points diagonally downwards in the z direction.Preferably, the pressure bar 13 is arranged in such a way that the fiber tape FB, starting from the fixing point P1 between the first pair of stretching rollers 7, 8, coincides with the upward-sloping, directed lateral surface of the pressure bar 13 and is guided through the convex surface of the pressure bar 13 perpendicularly to the second fixing point P2. The convex surface of the pressure bar 13 is therefore tangent to a perpendicular passing through the second fixing point P2 of the second pair of stretching rollers 9, 10. The inclined arrangement of the pressure bar at angle α just behind the first pair of stretching rollers 7, 8 facilitates the automatic insertion of the fiber tape FB into the stretching system 1.The tangential arrangement of the convex surface of the pressure bar 13 in relation to the perpendicular through the second fixing point P2, which is displaced in the x direction by the value V in relation to the first fixing point P1, favors the orientation of the short fibers, which can be stretched to a distance from the fixing line L1 of 35 up to and including L2 = 75 mm.

[0037] Textile improvements are mainly obtained in recycled fiber blends, which consist of a high proportion of short fibers, due to the fiber orientation through the pressure bar, which can be measured down to the yarn. The yarn strength increases by up to 8%, while the IPI (total IPI) values ​​decrease in the range of 10% to 20%.

[0038] As the first rollers 7, 8 of the stretching system are mounted together with the pressure bar 13 in an upper drive compartment Petition 870250089324, dated 10 / 01 / 2025, page 26 / 104 18 / 21 4a, which is separated from the lower drive compartment 4b of the second rollers 9, 10 of the stretching system, the distance of the fixing line L1, L2 can be changed using simple adjustment means without uncoupling the rollers 7, 8 of the stretching system from the drives and removing them. The distance between the pressure bar 13 and the first rollers 7, 8 of the stretching system does not change in this procedure.

[0039] Figure 5 shows the rear part of the stretcher according to the invention with the drive concept. The upper drive compartment 4a is completely separate from the lower drive compartment 4b and can be moved along the guide plate 24 by means of an adjustment element 23 not shown, so that the distance of the clamping line L1, L2 can be adjusted without adjusting the rollers 7, 8, 9, 10 of the stretcher system individually. Both the upper and lower drive compartments 4a, 4b each comprise a separate and independent drive, which is not influenced by the adjustment of the clamping line distance. The fact that all drive components are arranged at the rear of the stretcher means that the front part can be freely accessed, providing sufficient space for maintenance or cleaning. Therefore, it is not necessary to disassemble or adjust the drive components.Furthermore, the concept of the upper roller bearings 7, 9, in which the front cylinders 11b, 12b are arranged in the opposite direction to the rear cylinders 11a, 12b, facilitates the disassembly of the upper rollers 7, 9. After the upper rollers 7, 9 are disassembled, ample space is available in the remaining components of the stretching system for maintenance and cleaning.

[0040] The upper drive compartment 4a comprises a first drive 21, from which the second adjustable input measuring roller 6b and the first lower roller 7 are driven 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 Petition 870250089324, dated 10 / 01 / 2025, page 27 / 104 19 / 21 deflected by a deflection roller 29. In this process, the drive directions of the first and second input measuring rollers 6a, 6b are opposite, such that the fiber tape FB is transported vertically downwards through the input measuring rollers 6a, 6b. A sensor 27 is arranged on the stationary input measuring roller 6b, designed to determine the concentricity of this roller 6b and to compensate for possible irregular movement by means of the measurement technique. This allows for verification of the accuracy of the measurement of the determined tape mass deviation. The sensor 27 can be designed, for example, as a piston coil or a piezoelectric element. The first upper roller 8 is pressed by the pressure of the cylinders 11a, 11b in the roller bearings 8.4, 8.5 with the roller cover 8.1 against the first lower roller 7 and is thus driven by friction.The separation of the drives into an upper drive compartment 4a with the first pair of stretching rollers 7, 8 and a lower drive compartment 4b with the second pair of stretching rollers 9, 10 enables an adjustability of the distance of the fixing line L1, L2, wherein the stretching roller pairs at the speed of the lower rollers 7, 9 and the load pressure of the upper rollers 8, 10 can be controlled separately at the same time. At the same time, the driven measuring rollers 6b, 15b are decoupled from each other in terms of drive technology, so that it is not necessary to use cross belts.

[0041] The lower drive compartment 4b also comprises its own second drive 30, which is used simultaneously 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 by means of a second belt 32. The second belt 32 is deflected by the deflection roller 34, such that both output measuring rollers 15a, 15b are driven in opposite directions and pull the fiber tape FB between them, carrying Petition 870250089324, dated 01 / 10 / 2025, page 28 / 104 20 / 21 a for the base tube 40. A tensioning element 35 provides the necessary tension for the belt. A third belt 33 is driven by the second drive 30, which causes the can plate 41 to rotate. The drives 21, 30 can be designed as servo drives, which eliminates the need to change gears when the stretch field width or delay changes, depending on the fibers being processed.

[0042] Numerical references 1 Drafting system 2 Cover 2a, 2b Wings 3 Cover flap 3a Opening 4a, 4b Drive compartment 5 First hopper 6, 6a, 6b Pair of inlet measuring rollers 7 First lower roller 8 First upper roller 9 Second lower roller 10 Second upper roller 11a First cylinder 12a Second cylinder 13 Pressure bar 14 Second hopper 15a, 15b Pair of outlet measuring rollers 16 Stripper 17 Sensor 21 First drive 23 Adjustment element 24 Guide plate Petition 870250089324, dated 10 / 01 / 2025, page 29 / 104 21 / 21 26 First belt 27 Sensor 28 Second belt 29 Deflection roller 30 Second drive 31 First belt 32 Second belt 33 Third belt 34 Deflection roller 35 Tensioning element 36b Lever 37 Tube 40 Base tube 41 Can plate A Base FB Fiber tape K Card L1, L2 Distance from the fixing line P1, P2 Fixing point R Deflection roller S Accumulator V Displacement W Can changer x, y, z Direction α Pressure bar angle Petition 870250089324, dated 10 / 01 / 2025, page 30 / 104

Claims

1 / 3 CLAIMS 1. Method for separating a single carded fiber sliver (FB) during can change in a stretching (1), wherein the fiber sliver is generated in a carding machine (K) and travels uninterrupted to the stretching system (1), which is disposed in the upper part of the can changer (W) associated with the carding machine (K), wherein the fiber sliver (FB) is guided vertically through a main delay field of the stretching (1) to a hopper (14) and subsequently to a pair of take-off rollers that guide the fiber sliver (FB) into a base tube (40) of a can plate (41) in continuous rotation into a can, characterized by comprising the following steps: - reduction of the speed of the can plate (41) to a fiber sliver (FB) delivery speed of 50 m / min to 300 m / min, - introduction of compressed air into the hopper (14) to generate a suction current in the fiber tape (FB),- creation of a fine point on the fiber sliver (FB) in the main delay field of the stretching system, - routing of the fiber sliver (FB) with the fine point through the hopper (14) subjected to compressed air, through the removal rollers, into the base tube (40) of the can plate (41), - activation of the can changer and therefore the separation of the fiber sliver (FB) as soon as the fine point of the fiber sliver (FB) has reached the exit of the rotating can plate (41), - introduction of the fiber sliver (FB) into the empty can and operation of the carding machine (K) with the stretching system (1) and the can changer (W) at production speed.

2. Method according to claim 1, characterized in that the fine point is generated with a length of 20 mm to 200 mm, preferably with a length of 50 mm.

3. Method according to claim 1, characterized in that the mass of the fiber tape (FB) at the thinning point is reduced by 60% to 100% of the original tape mass, preferably by 80% of the original tape mass. Petition 870250089324, dated 10 / 01 / 2025, page 31 / 104 2 / 3 4. Method according to claim 1, characterized in that the main delay field is formed by a first pair of stretching rollers (7, 8) in the material transport direction and a second pair of subsequent stretching rollers (9, 10), wherein the thin spot on the fiber strip (FB) is generated by increasing the speed of the second pair of stretching rollers (9, 10) or by reducing the speed of the first pair of stretching rollers (7, 8).

5. Method, according to any of the preceding claims, characterized in that the stretching (1) with the can changer (W) is controlled by the carding control system (K), wherein compressed air is introduced into the second funnel (14) for a predetermined time before, during and after the generation of a thin spot on the fiber tape (FB) during a can change, the predetermined time being able to be entered into the carding control system (K).

6. Stretching system for stretching a single carded fiber sliver (FB) characterized in that the fiber sliver is generated in a carding machine (K) and travels without interruption into the stretching system (1), which is arranged in the upper part of the can changer (W) associated with the carding machine (K), which has a first upper funnel (5), in the material flow direction, a pair of inlet measuring rollers (6a, 6b) followed by a sensor, which has a following stretching system, in the material flow direction, arranged vertically with a main delay field and a second funnel (14) followed by the material flow direction, which is designed to generate a suction current within the stretching system (1) by means of the introduction of compressed air and, subsequently, a pair of rollers designed to extract the fiber sliver (FB) to the base tube (40) of a can plate (41) in continuous rotation.

7. Stretching system according to claim 6, wherein the stretching system is characterized by being designed as a 2-over-2 stretching system, with a first and a second pair of stretching rolls (7,8; 9,10), wherein the second pair of stretching rolls (9, 10) is arranged at a horizontal offset (V) relative to the first pair of stretching rolls (7, 8), and a pressure bar (13) is arranged below the first pair of stretching rolls (7, 8) so that the fiber tape (FB) is guided perpendicularly from a convex pressure bar surface (13) to the upper reinforcement of the second pair of stretching rolls (9, 10).

8. Stretching system according to claim 6, characterized in that the pair of rollers for removing the fiber tape (FB) to the base tube (40) is designed as a pair of output measuring rollers (15a, 15b).

9. Stretching system according to claim 8, characterized in that the pair of output measuring rollers (15a, 15b) has a sensor whose signals are transmitted to the carding control system (K).

10. Stretching system according to claim 6, characterized in that a sensor (17) monitors the entry of the base tube (40) for rupture or jamming of the fiber tape (FB). Petition 870250089324, dated 10 / 01 / 2025, page 33 / 104

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