Method for detecting formation of at least one weak point of spun yarn, device for data processing, monitoring device, spinning machine, computer program and computer-readable medium

Abstract

To provide a method for detecting formation of at least one weak point in a spun yarn, particularly in an air-spun yarn.SOLUTION: There is provided a method for detecting formation of at least one weak point in a spun yarn, particularly in an air-spun yarn in a spinning machine, comprising the steps of: receiving at least one detection value resulting from optical detection of the yarn, the at least one detection value being characteristic of the brightness of a yarn; evaluating at least one detection value for detecting an irregularity related to the brightness of a yarn; and detecting formation of at least one weak point based on the detected irregularity. There are also provided a device for data processing, a monitoring device, a spinning machine, a computer program, and a computer-readable medium.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a method for detecting the formation of at least one weak point in spun yarns, in particular air-spun yarns, a device for data processing, a monitoring device, a spinning machine, a computer program and a computer-readable medium. [Background technology]

[0002] Reliably detecting the occurrence of weak points in spun yarns, especially air-spun yarns, is often difficult or possible only very late. Such weak points are a known problem, especially with air-jet spun yarns, and are detected very late or sometimes not at all. Thus, shorter and longer lengths with defective yarn points can end up on the spool, leading to longer downtimes during further processing and additional cost issues.

[0003] EP 2169097 A1 discloses a device for detecting foreign objects on spun yarn.

[0004] WO 2021 / 223784(A1) discloses a method for detecting fully formed structural defects in spun yarns by light matching.

[0005] In particular, it is an object of the present invention to provide a particularly alternative or improved solution for detecting the formation of at least one weak point in spun yarns, in particular air-spun yarns, which is characterized in particular by its cost-effective practicality and preferably by its reliable early detection of at least one weak point in spun yarns, in particular air-spun yarns.

[0006] The above-mentioned objects are achieved by a method, a device for data processing, a monitoring device, a spinning machine, a computer program, and a computer-readable medium having the features of the corresponding independent claims. Further features and details of the invention are evident from the respective dependent claims, the description, and the drawings. Features and details explained in connection with the method according to the invention also apply in connection with the device according to the invention for data processing, the monitoring device according to the invention, the spinning machine according to the invention, the computer program according to the invention, and the computer-readable medium according to the invention, and vice versa in each case, so that when disclosing individual aspects of the invention, reference is always made or can be made reciprocally to other aspects. Summary of the Invention

[0007] Disclosure of the Invention According to one aspect, the object is achieved in particular by a method for detecting the formation of at least one weak point in a spun yarn, in particular an air-spun yarn, in a spinning machine.

[0008] According to a first method step, the method according to the invention comprises receiving at least one detection value resulting from the optical detection of the yarn, the at least one detection value being characteristic of the brightness of the yarn, i.e., in particular of the amount of light emitted by the yarn that is reflected (and also re-emitted), preferably diffusely reflected, by the yarn upon illumination. The detection value may therefore preferably be a brightness value and / or a brightness degree indicative of the degree of reflection emanating from the yarn. To enable optical detection of the yarn, illumination of the yarn with a predetermined light intensity and / or illuminance may be provided.

[0009] According to a further method step, the method according to the invention comprises evaluating at least one detected value in order to determine irregularities with respect to the yarn brightness. In particular, deviations of the light intensity emitted by the yarn from at least one reference light intensity, preferably from a reference light intensity range (reference), can be determined. The evaluation is provided, for example, by digital processing of the at least one detected value, for example by numerical comparison of the at least one detected value or values ​​with a reference.

[0010] Furthermore, according to a further method step, the method according to the present invention comprises detecting the formation of at least one weak point based on the detected irregularity. For this purpose, for example, deviations are checked and / or a warning signal is issued when a deviation is detected, in particular after detection over a predetermined period of time. This provides a method for detecting the formation of at least one weak point in a spun yarn, in particular an air-spun yarn, which method is characterized in particular by its cost-effective practicality and preferably by its reliable early detection of at least one weak point in a spun yarn, in particular an air-spun yarn. Preferably, receiving occurs before evaluation, and evaluation occurs before detection.

[0011] A particular advantage that can result from the method according to the invention is that, in contrast to conventional solutions, formed vulnerabilities are not (only) detected, but rather it is possible to detect vulnerabilities in an early phase of their formation so that measures can be taken against their formation at an early stage.

[0012] Advantageously, the method is carried out during a spinning process, in particular an air spinning process, during which the yarn is spun, in particular air spun, and the yarn is monitored for the formation of at least one weak point by the method according to the invention. The spinning process can be carried out by a spinning machine, in particular using a spinning station of the spinning machine. The spinning machine is preferably an air spinning machine, which can have multiple spinning stations. Alternatively, the spinning machine can be a rotor spinning machine. The process steps can preferably be carried out repeatedly, in particular during the spinning process.

[0013] In principle, at each point of disclosure in the preferred embodiments of the proposed method and the proposed device, if a yarn or spun yarn is involved, in particular an air-spun yarn, then it is preferred that said yarn is involved.

[0014] The method is useful when used to detect the formation of multiple weak points or at least one weak point segment in a yarn, thereby allowing the formation of an entire weak area or entire weak area in the yarn to be identified.

[0015] Furthermore, the proposed method is preferably initialized when a spinning process is initialized, the spinning process being intended to spin a yarn that is to be monitored for the formation of at least one weak point by the method, thereby ensuring that the yarn spun by the spinning process is monitored from the very beginning with the method.

[0016] Furthermore, it is preferable to consider that the proposed method is repeated for as long as one or more spinning processes in which a yarn is spun and monitored for the formation of at least one weak point using the proposed method continues. This ensures continuous monitoring of the spun yarn. It cannot be excluded that the spinning process may be temporarily interrupted for maintenance or cleaning work. Therefore, it is preferable that the proposed method is also interrupted during interruptions of the spinning process. This makes it possible to save resources, especially energy, for implementing the proposed method.

[0017] Furthermore, the proposed method is preferably terminated when the spinning process in which the yarn monitored for the formation of at least one weak point by the proposed method is spun is finished, which makes it possible to save resources, in particular energy, when carrying out the process.

[0018] To interrupt and / or terminate the proposed method, components used in the method such as sensors and / or light sources such as light emitting diodes may be switched off.

[0019] The at least one weak point is preferably a point on the yarn having a strength, particularly a tensile strength, below a predetermined strength threshold. A weak point is preferably understood to be a structural defect, which is characterized in particular by the fact that the yarn is missing wrapping fibers or that wrapping fibers are not present in sufficient numbers. Wrapping fibers surrounding the yarn core are particularly important for the strength of air-spun yarns.

[0020] Preferably, the at least one detection value resulting from the optical detection of the yarn is or is detected by at least one optical sensor. In other words, as part of the method, the at least one detection value is or is preferably provided by at least one optical sensor for the receiving method step. The at least one optical sensor is preferably at least one brightness sensor or at least one photodiode. In this way, the at least one detection value specific to the brightness of the yarn can be determined relatively simply and inexpensively. Preferably, there are exactly one, two, or three such sensors. The at least one optical sensor is described in more detail in connection with the monitoring device according to the invention. The optical sensor can be one or two reflective diodes, in particular shading diodes.

[0021] According to a preferred embodiment, the evaluation of the at least one detected value may further comprise the step of comparing the at least one detected value, in particular a lightness value, preferably corresponding to a degree of lightness of the yarn, with at least one reference value, preferably a lightness reference value, in order to determine an irregularity based on a deviation of the at least one detected value from at least one reference value, wherein preferably the formation of at least one weak point is detected based on a quantitative evaluation of the deviation, preferably the at least one weak point being detected thereby in the form of a structural defect in the yarn. In particular, the at least one reference value may specify at least a reference amount of light reflected by the yarn.

[0022] In principle, it is preferred that the lightness value and / or the lightness reference value is a yarn reflectance value. This allows the formation of at least one weak point in the spun yarn to be detected more accurately than, for example, by detecting the yarn diameter solely on the basis of the determined shading value. However, it is preferred that the detection of the yarn diameter based on the determined shading value is taken into account when evaluating the at least one detected value, in particular the lightness value. In this way, it is possible to compensate for interference effects that may distort or manipulate the at least one detected value, in particular the lightness value.

[0023] Regardless of this, it is also generally preferred that any type of value used by the proposed method, for example, at least one detected value or at least one reference value, is in the form of data, digital data, or a digital signal. Furthermore, it is preferred that the value is present in a manner that allows it to be processed by a data processing device. This simplifies the processing of the relevant values. Furthermore, the method can be particularly reliably implemented by a data processing device, in particular a computer. Not only the at least one detected value, but also the reference value in particular, can be measured values ​​or measurement data. In this way, the values ​​in question can also be more easily documented. For example, a spool of spun yarn can be provided with documentation of detected values, especially in the form of data, to indicate the properties of the yarn or to take the properties of the yarn into account during its further processing, in particular by a textile machine.

[0024] Furthermore, according to a preferred embodiment, irregularities in the yarn lightness can be determined when at least one lightness value of the yarn or a value derived therefrom falls below at least one lightness reference value. Values ​​derived from lightness values ​​preferably mean that the derived values ​​result from further processing of at least one lightness value, for example, by statistical methods and / or mathematical formulas. Other values, such as values ​​characteristic of the yarn diameter, can also be taken into account. In this way, compensation factors for compensating for yarn impurities or offset values, for example, can also be taken into account. If additional values ​​are taken into account, these values ​​are preferably also received in the form of detected values. The derived values ​​can be used to eliminate or at least partially, preferably largely or completely compensate for various interfering effects, thereby improving or standardizing the accuracy of the values. It is further preferred that the formation of a weak point in the yarn is not detected if at least one lightness value of the yarn or a value derived therefrom does not fall below at least one lightness reference value. Furthermore, in such a case, the relevant spinning process is preferably carried out, and / or the method is preferably repeated, starting again from the reception of at least one, in particular a further, detected value, as long as no weak point in the yarn is detected. Preferably, the yarn brightness value decreases as the yarn brightness decreases. Alternatively, according to a preferred embodiment, it is contemplated that the brightness value is inversely proportional to the yarn brightness, i.e., decreases as the yarn brightness decreases. This depends on the particular application.

[0025] Furthermore, an irregularity with respect to the brightness of the yarn is preferably detected only if at least one brightness value of the yarn or a value derived therefrom is at least 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, or 5% below at least one brightness reference value.

[0026] Furthermore, according to a preferred embodiment, at least one detection value, in particular a brightness value, -Multiple brightness values, - lightness value curve, -Change in brightness value, - brightness value change rate, And preferably, at least one reference value, in particular a brightness reference value, is -Multiple brightness reference values, -Lightness reference curve, - Change in brightness reference value, - The brightness reference value change rate.

[0027] By suitably using each of the above-mentioned detection or reference values ​​in the specified order, the formation of at least one weak point in the spun yarn can be detected more accurately, while the effort required to carry out the method is thereby only slightly increased.

[0028] The lightness value change preferably refers to a previously, in particular immediately preceding, detected lightness value. This means that the difference between the received lightness value and the previously received lightness value is preferably determined. For example, a maximum lightness value change of 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, or 5% can be allowed. The smaller the maximum allowed lightness value change, the earlier the occurrence of a weak point in the yarn can be detected by the method.

[0029] Furthermore, it is preferred that the lightness value curve consists of a plurality of lightness values ​​and / or the lightness reference value curve consists of a plurality of lightness reference values, the lightness value curve preferably referring to lightness values ​​detected one after the other over the length of the yarn.

[0030] Furthermore, it is advantageous if a trend, preferably a trend of future lightness values, can be derived from the at least one detected value, in particular the lightness value, preferably by means of a statistical method or a mathematical formula, whereby the formation of at least one weak point in the yarn can be detected, thereby ensuring early detection of at least one weak point in the yarn.

[0031] Furthermore, according to a preferred embodiment, it is conceivable that at least one detected value, preferably a brightness value, corresponds to an average value, and preferably at least one reference value, in particular a brightness reference value, corresponds to an average value. Preferably, one or more average values ​​are averaged over a defined length of the spun yarn or over a defined period of the spinning process. The use of average values ​​can largely eliminate short-term fluctuations in the detected values, which may lead to inaccurate detection of the formation of at least one weak point in the yarn. Preferably, the average value is calculated over a length of 50, 100, 200, or 250 meters of the yarn. These lengths have been shown to allow for the detection of weak points with an acceptable level of reliability. However, the longer the length over which the average is calculated, the lower the risk of false detection. Therefore, according to an alternative preferred embodiment, the average value can also be calculated over a length greater than 250 meters, preferably within a range from 250 meters to 1,000 meters, with a low risk of false detection. However, lengths much greater than 1,000 meters have a negative impact on productivity. In addition, it becomes possible to compensate for manufacturing variations during the spinning process, which do not necessarily result in the occurrence of weak points in the yarn.

[0032] According to a preferred embodiment, impurities in the yarn, particularly foreign particles and / or foreign fibers, can be taken into account during the evaluation to compensate for the influence of impurities on at least one detected value. For this purpose, an impurity calibration is preferably performed when the spinning of the yarn is stopped. Foreign fibers are preferably understood to mean fibers not used to form the spun yarn. Taking impurities into account during the evaluation ensures that such impurities do not lead to a false detection of the formation of at least one weak point in the spun yarn. Tests have shown that, in particular, one-third of the change in brightness value is due to impurities and two-thirds of the change in brightness value is due to the formation of at least one weak point in the spun yarn. Preferably, this ratio is taken into account when considering impurities during the evaluation. Alternatively, other ratios, such as one-quarter to three-quarters of the change in brightness value due to impurities to the change in brightness value due to the formation of at least one weak point in the spun yarn, are also possible. The impurity calibration preferably provides improved results compared to the mere assumption of such a ratio, which may be based on empirical values. The impurity calibration comprises, for example, a comparison of at least one detected value before washing with one detected value after washing, preferably for the same yarn position area or the same yarn section, such that the influence of existing impurities on the detected value can be determined and used to continue the method for compensating for the influence of impurities on the at least one detected value, in particular the brightness value.

[0033] Furthermore, according to a preferred embodiment, it is conceivable to take into account an offset value for the necessary compensation of the impurities determined by the impurity calibration, which offset value preferably takes into account dynamic effects during the spinning process. Stopping the spinning of the yarn is preferably understood to mean an interruption of the spinning process in which the yarn monitored by the proposed method is spun. Interruption preferably means that the spinning process is or can be continued after the impurity calibration.

[0034] Furthermore, according to a preferred embodiment, it is envisaged that the detection of the formation of the at least one weak point occurs before the at least one weak point is fully formed, and the detection of the formation of the at least one weak point preferably occurs in the form of detection of a missing or incorrectly positioned wrapping fiber in the yarn. The wrapping fiber can be crucial for the strength of the air-spun yarn. Preferably, the wrapping fiber affects the brightness of the yarn and thus the at least one detection value, in particular the brightness value. By detecting the formation of the at least one weak point in the yarn before the at least one weak point in the yarn is fully formed, further problems during processing, such as longer downtimes and additional costs, are avoided.

[0035] Furthermore, the method according to the preferred embodiment comprises: - It is possible to include a step of initiating a reaction to the detection of the formation of at least one weak point, for which purpose an output is generated when the formation of at least one further weak point in the yarn is detected, which triggers a cleaning, in particular a pneumatic cleaning, of the spinneret of the spinning machine, in particular after at least one pre-cleaning of the spinneret or the spinneret of the spinning machine and / or an end or interruption of the spinning process of the spinning machine and / or maintenance of the spinning machine, in particular after at least one pre-cleaning of the spinneret or the spinneret of the spinning machine.

[0036] Cleaning is understood to mean, in particular, an automated cleaning process of the spinning device, preferably a mechanical or pneumatic cleaning process. Cleaning often eliminates the cause of at least one weak point in the spun yarn. Interrupting the spinning process of a spinning machine is understood to mean interrupting the spinning process, preferably at only one spinning position of the spinning machine, where the formation of at least one weak point in the yarn was detected. This makes it possible, in the case of a spinning machine with multiple spinning positions, to continue the spinning process at spinning positions where no such formation was detected. This contributes to a particularly efficient production process. Preferably, one or more impurity calibrations are performed when the spinning process is interrupted. If, during the continuation of the spinning process, a further formation of at least one weak point in the air-spun yarn is detected within a certain period after cleaning or a new cleaning of a spinning device, such as a spinneret or spinning rotor, it is assumed that cleaning of the spinning device did not stop the formation of the weak points, and that further cleaning will not stop the formation of the weak points either. Therefore, in such cases, maintenance of the spinning machine, in particular at the affected spinning position of the spinning machine, is preferably initiated. For this purpose, a message is preferably generated, which is for example displayed on a screen, requesting maintenance of the spinning machine or the affected spinning position, or is displayed, for example, by a defined signal color of a signal light at the spinning position. After cleaning or maintenance, the continuation of the spinning process of the spinning machine, in particular of the affected spinning position of the spinning machine, is preferably initiated, and the proposed method is preferably also initiated and resumed from the reception of at least one detection value.

[0037] Furthermore, according to a preferred embodiment, it is conceivable that the proposed method checks the spinning pressure and / or the vacuum of the suction during the spinning process. Such suction preferably assists in cleaning the yarn. For this purpose, a change in the suction force of the suction and / or a change in the spinning pressure of the spinning process, monitored by the proposed method, preferably occurs in response to the detection of the formation of at least one weak point in the yarn. This makes it possible to eliminate or suppress the formation of at least one weak point in the yarn. Furthermore, it is conceivable that damage or wear of the spinning device is detected using at least one received value, in particular since this damage or wear causes the formation of at least one weak point. In such cases, maintenance of the spinning machine or spinning device is preferably carried out, in particular the replacement of the spinneret or spinning rotor with a new spinneret or spinning rotor, and the spinning process is interrupted for this purpose in particular.

[0038] Further, according to a preferred embodiment, the method comprises: - determining a point in time of the spinning operation of the spinning machine at which at least a first detection value, in particular in the form of a reflectance value of the yarn, is received, - defining a length of the thread for which at least a first detection value is received, - starting from a defined point in the spinning process and for a defined length of the yarn, receiving at least first detection values ​​in order to form at least one reference value, preferably by averaging, from the received at least first detection values, - starting to receive at least one further detection value, in particular repeatedly for a defined length or a further defined length of the yarn, to obtain at least one current detection value from the at least one further detection value for the further spinning process, preferably by averaging, wherein the detection of the formation of at least one weak point in the yarn is carried out based on a comparison of the current detection value with at least one reference value, and it is conceivable that the formation of at least one weak point in the yarn is preferably detected when the current detection value deviates from the reference value by a defined amount.

[0039] In this way, at the start of the proposed method, a reference value is generated, which serves as a basis for the further course of the method. Furthermore, the formation of an average value compensates for production fluctuations during the spinning process, which may otherwise lead to a false detection of the formation of weak points in the spun yarn.

[0040] The deviation can be, for example, an undershoot or overshoot that is defined as unacceptable. The amount of deviation can preferably be set for each yarn batch or can be variably adjustable. Furthermore, the amount of deviation can preferably be retrieved from a knowledge store, which preferably includes at least one readable, in particular further rewritable, amount for the deviation depending on the yarn batch to be produced, in particular further including quality requirements for the yarn to be spun or the yarn batch to be produced, which requirements can be specified, for example, by the customer. This makes it possible to produce customer-specific yarn batches with respect to yarn quality.

[0041] According to a further aspect, the subject matter of the present invention also includes a device for data processing, which includes means for implementing the proposed method. The proposed device for data processing thus offers the same advantages as those described in detail with reference to the proposed method according to one of the preferred embodiments. The device for data processing can be integrated into a control device for the spinning machine or spinning station, or into a higher-level control device in the spinning machine. This is advantageous when the control device is designed to influence the operation of the spinning machine. In particular, it is preferred that the control device is part of the spinning machine or spinning station. This improves compactness, since a separate device for data processing does not need to be provided in addition to the control device.

[0042] The proposed device for processing data, for example, for executing a computer program, can be provided as a computer. The computer can have at least one processor for executing the computer program. A non-volatile data memory can also be provided in which the computer program can be stored and from which the computer program can be read by the processor for execution. Furthermore, the computer program can also be directly integrated into the machine software of the machine.

[0043] According to a preferred embodiment, it is also contemplated that the computer includes at least one integrated circuit, such as a microprocessor or an application-specific integrated circuit (ASIC), or an application-specific standard product (ASSP), or a digital signal processor (DSP), or a field-programmable gate array (FPGA). The computer may further have at least one interface for data exchange, such as an Ethernet interface, or an interface for a LAN (local area network) or a WLAN (wireless local area network) or a system-on-chip (SoC), or other wireless interface, such as Bluetooth or near-field communication (NFC). Furthermore, the computer may be implemented as one or more control devices, i.e., a system of control devices. For example, the computer may be provided in the cloud and / or as a server to process data for local applications via the interface. The computer may also be implemented as a mobile device, such as a smartphone.

[0044] According to a further aspect, the subject matter of the present invention also includes a monitoring device, in particular a yarn clearer, that includes the proposed device for data processing. In this way, the functionality generated by the proposed method can be very easily integrated into existing devices, in particular yarn clearers. In addition, to implement the proposed method, optical sensors already provided in yarn clearers, in particular those used to identify impurities in the yarn, can be used. In other respects, the proposed monitoring device offers the same advantages as those described in detail with reference to the proposed method according to one of the preferred embodiments.

[0045] The monitoring device may include an artificial light source, in particular an infrared light-emitting diode, for irradiating the yarn with light, in particular infrared light; at least one or exactly two optical sensors, preferably photodiodes, in particular reflecting diodes, for detecting light from the light source reflected by the yarn, the diodes being arranged adjacent to the light source; and a third optical sensor, preferably a third photodiode, preferably arranged behind the yarn from the light source, for detecting shading resulting from the light source and the positioning of the yarn relative to the light from the light source. The optical sensor is preferably a sensor for measuring brightness, in particular a brightness sensor. The yarn preferably passes through a measuring chamber of the monitoring device, in particular a yarn clearer, which separates the light source with at least one optical sensor for detecting light from the light source reflected by the yarn on one side from the optical sensor for detecting shading on the other side. The optical sensor and the light source are preferably located in a plane perpendicular to the yarn transport direction or the longitudinal axis of the yarn. Furthermore, it is preferred that the light source for irradiating the yarn with light and the at least one optical sensor for detecting light reflected by the yarn are coordinated with each other, and in particular with respect to the yarn, so that the brightness of the yarn can be determined by the at least one optical sensor in response to illumination of the yarn with light from the light source.

[0046] According to a further aspect, the subject matter of the present invention also relates to a spinning machine, in particular an air spinning machine, including at least one of the proposed monitoring devices. The proposed spinning machine thus offers the same advantages as those described in detail with reference to the proposed method according to one of the preferred embodiments. The spinning machine preferably has multiple spinning stations for spinning spun yarns, in particular air spun yarns, in a conventional manner. Each spinning station preferably includes the proposed monitoring device. Thus, by means of the proposed method and the proposed monitoring device, multiple parallel spinning processes of the spinning machine can be monitored so that the formation of at least one weak point in the spun yarn, in particular air spun yarn, can be detected. This results in a particularly productive spinning machine. Furthermore, the spinning machine preferably includes a control device.

[0047] The subject matter of the present invention also includes a computer program comprising instructions that cause a computer to implement the proposed method when the computer program is executed by a computer. According to a further aspect, the subject matter of the present invention also includes a computer program product comprising instructions that cause a computer to implement the proposed method when the computer program is executed by a computer. The proposed computer program and the proposed computer program product therefore provide the same advantages as those described in detail with reference to the proposed method according to one of the preferred embodiments.

[0048] According to a further aspect, the subject matter of the present invention also includes a computer-readable medium on which the proposed computer program is stored. The computer-readable medium is preferably designed as a storage medium, e.g., a data memory, such as, for example, a hard disk and / or a non-volatile memory and / or a memory card. The storage medium can, for example, be integrated into a computer or a control device. The computer-readable medium according to the present invention therefore offers the same advantages as those described in detail with reference to the proposed method according to one of the preferred embodiments.

[0049] Additionally, the proposed method according to the invention can in particular in principle also be realized as a computer-implemented method. [Brief explanation of the drawings]

[0050] Further advantages, features and details of the invention will become apparent from the following description in which exemplary embodiments of the invention are described in detail with reference to the drawings. The features described in the claims and in this specification may be essential to the invention individually or in any combination.

[0051] The drawings are as follows: [Figure 1] 1 illustrates an exemplary embodiment of a method. [Figure 2] 1 shows a schematic representation of a lightness value curve; [Figure 3] 1 shows a schematic illustration of an exemplary embodiment of a spinning machine; [Figure 4] 1 illustrates schematically an exemplary embodiment of a monitoring device;

[0052] In the following figures, the same reference signs are used for the same technical features even in different exemplary embodiments.

[0053] 1 shows a schematic representation of one embodiment of a method 100 for detecting the formation of at least one weak point in an air-spun yarn. A weak point is preferably understood to be a structural defect, characterized by the fact that the yarn is missing wrapping fibers or that these fibers are not present in sufficient numbers. First, an initialization 101 of the method 100 is performed, which is preferably performed simultaneously with the start of the spinning process of the spinning machine in which the method 100 is used.

[0054] Next, at least one detection value is received 102. The at least one detection value is characteristic of the yarn lightness and is preferably determined by at least one optical sensor.

[0055] This is followed by an evaluation 103 of the at least one detected value to determine irregularities related to the yarn lightness. The evaluation 103 comprises comparing the at least one detected value with at least one reference value to determine irregularities based on deviations of the at least one detected value from the at least one reference value. The at least one detected value corresponds to a yarn lightness value, while the reference value corresponds to a lightness reference value.

[0056] The next step is detecting 104 the formation of at least one weak point in the air-spun yarn based on the detected irregularities. Such irregularities can be used to identify the weak points to be detected. If such irregularities are determined, the formation of at least one weak point in the yarn is detected. If such irregularities are not determined, the absence of a weak point is detected. In other words, in such a case, if no such irregularities are found, the yarn can be assumed to be free of weak points. If no weak points in the yarn are detected, the method is preferably repeated, beginning again with receiving 102 at least one further detection value, as long as the yarn is air-spun by the spinning machine.

[0057] However, if the formation of a weak point is detected, an output is preferably generated 105 in response to the detection 104 of at least one weak point. This triggers an interruption of the spinning process of the spinning machine and automated pneumatic cleaning of the spinneret of the spinning machine, since it can be assumed with a high degree of certainty that an impurity in the spinneret of the spinning machine caused the formation of the at least one weak point. Such an impurity is typically a foreign fiber. After cleaning, continuation of the spinning process of the spinning machine is preferably initiated, and method 100 is repeated, starting again with reception 102 of a detection value, in particular a further detection value. If a further formation of at least one weak point in the air-spun yarn is detected within a certain period after cleaning of the spinneret or after a new cleaning, it is assumed that the cleaning of the spinneret has not stopped the formation of the at least one weak point in the yarn, and that the new cleaning has not stopped the formation of the at least one weak point. In such a case, an interruption of the spinning process of the spinning machine is initiated. In addition, an output is generated to initiate maintenance of the spinning machine. For example, for this purpose, a message can be generated that displays a message on a screen requesting maintenance of the spinning machine. After the maintenance, the method 100 can be repeated, starting again with the reception of at least one, in particular a further detection value, 102. When the spinning process of the spinning machine is finished, the method 100 also preferably ends 106.

[0058] Preferably, the method 100 is computer-implemented. Furthermore, it is preferred that the at least one detected value and the at least one reference value are present as data, in particular as digital data.

[0059] Furthermore, it is preferred that at least one detection value and / or at least one reference value is present as an average value averaged over the length of the yarn, for example averaged over 100 meters. The reference value is preferably formed by calculating an average value over a defined length of the yarn. Such formation of the reference value can take place before initialization of the method 100.

[0060] 2 shows a schematic diagram of a lightness value curve 201. The abscissa 204 represents the length of the air-spun yarn, and the ordinate 205 quantitatively describes the lightness of the individual lightness values ​​202. The individual lightness values ​​202 are averaged over the yarn length to form the lightness value curve 201. Furthermore, a lightness reference value 203 is shown. If at least one of the lightness value curve 201 or the lightness values ​​202 falls below the lightness reference value 203, a lightness irregularity of the yarn is determined. In a further embodiment, the lightness reference value 203 is preferably formed as the lightness reference value curve.

[0061] FIG. 3 shows a schematic diagram of one embodiment of a spinning machine 301. The spinning machine 301 is an air-spun spinning machine. The spinning machine 301 is designed to produce air-spun yarn 313. To this end, the spinning machine 301 includes a spinneret 308, a suction device 307, and a monitoring device 306. The monitoring device 306 is designed to implement the method 100. The monitoring device 306 is preferably a yarn clearer 314, which is further designed to detect impurities in the yarn. The yarn clearer 314 includes an artificial light source 309a designed as a light-emitting diode 309b, in particular an infrared light-emitting diode 309c. Additionally, the monitoring device 306 includes at least one, preferably three, optical sensors 310a, 310b, 310c. The at least one, preferably three, optical sensors 310a, 310b, 310c are preferably designed as brightness sensors or photodiodes. The first two optical sensors are preferably reflective diodes and the third optical sensor is a shading diode.

[0062] The light-emitting diode 309b can be operated by a device for data processing 304, in particular a computer. Values ​​detected by the optical sensors 310a, 310b, and 310c can be transmitted to the device for data processing 304 via a cable. The device for data processing 304 is preferably integrated into a control device 305 of the spinning machine 301. The spinning machine 301 can also be operated by the control device 305. The device for data processing 304 further includes a computer-readable medium 303, preferably designed as a non-volatile memory, on which a computer program 302 is stored. The computer program 302 contains commands that, when executed by the device for data processing 304, cause the device for data processing 304 to perform the method 100. Although the device for data processing 304, the computer-readable medium 303, and the computer program 302 are shown external to the monitoring device 306 in FIG. 3, this is not required and is merely optional.

[0063] 4 shows a schematic embodiment of the monitoring device 306, which is designed as a yarn clearer 314. In contrast to the illustration of FIG. 3, the device for data processing 304, which has the computer-readable medium 303 and the computer program 302, is integrated into the yarn clearer 314. The illustration of FIG. 4 shows a plane perpendicular to the conveying direction of the yarn 313 through the yarn clearer 314. In other words, the view of FIG. 4 is perpendicular to the longitudinal axis of the yarn 313. The yarn 313 can be conveyed through a measuring chamber 316 of the yarn clearer 314. By means of an artificial light source 309a, which is preferably designed as an infrared-emitting diode 309c, the yarn 313 conveyed through the yarn clearer 314 is illuminated with light, preferably infrared light. In response to this illumination, while being transported, the thread 313 reflects the illuminated light toward two optical sensors 310a, 310b, which are arranged adjacent to the artificial light source 309a and are preferably designed as reflective diodes. The third optical sensor 310c is located behind the thread 313 from the perspective of the artificial light source 309a, so that the shading resulting from the arrangement of the thread 313 and the artificial light source 309a is detected by the third optical sensor 310c. The optical sensors 310a, 310b, 310c are preferably designed as brightness sensors 311a, 311b, 311c or photodiodes 312a, 312b, 312c. The values ​​detected by the optical sensors 310a, 310b, 310c can be transmitted via cable 315a to the device 304 for data processing. Via a further cable 315b, the device for data processing 304 is able to initiate maintenance of the spinning machine 301 by generating and displaying on the monitor a message requesting maintenance of the spinning machine.

[0064] Further embodiments of the present invention are described below.

[0065] In the measuring chamber of the yarn clearer, differences in the brightness of the spun yarn are detected, particularly in the form of reflectance values. Traditionally, this is often only used to detect any kind of foreign fiber by the change in brightness and then remove it from the yarn. One of the ideas underlying an alternative embodiment of the present invention is to use the brightness differences detected by the yarn clearer for early detection of the formation of weak points in the yarn.

[0066] Weak points usually form when the wrapping fibers required for air-spun yarns do not wrap around the yarn core, thus causing the yarn to lose its typical properties. Only the wrapping fibers provide the yarn with the necessary strength. Therefore, interference in the formation of the wrapping fibers can inevitably result in undesirable weak points in the yarn.

[0067] The interference-free formation of tortuous fibers is fundamentally dependent on certain influences. These include, for example, spinning pressure, interference-free suction of dirt and debris, and accurate positioning of the spinneret and related components for forming the thread or yarn. Furthermore, it is often essential to use only suitable, undamaged components in the area where the thread is formed, in particular suitable spinnerets of the spinning machine.

[0068] Variations of the present invention allow the adverse effects of the aforementioned interference to be detected in time. For example, a yarn clearer can detect yarn values ​​using a defined scan. In particular, changes in brightness, especially compensated for dirt, can be continuously detected and calculated. Changes in yarn properties can affect reflectivity and therefore brightness.

[0069] If one of the aforementioned interferences occurs in the yarn formation process, this can directly affect the required wrapping fibers. According to an alternative embodiment of the present invention, missing wrapping fibers or wrapping fibers not located around the thread change the brightness of the yarn and can therefore be reliably detected in reflectance.

[0070] The reflectance value of the yarn can be detected and an average value, preferably a reference value, can be calculated over a specific length. This reference value can be set and saved. An average value can then be calculated for the yarn being spun over a specific length, e.g., 100 meters, and compared to the reference value. The deviation of the brightness from the reference value to the current average value for the specific length can then be used to detect changes in yarn properties, and thus changes in the wrapping fiber. The spinning position can be switched off to check for faults. This means that weak points are identified not only when they exist, but also when they are forming.

[0071] An extended embodiment detects the formation of weak spots even when unevenly colored or dark yarns are spun. For this purpose, infrared light-emitting diodes can be used to illuminate the yarn. As a result, the reflectance, and therefore the brightness, is affected by the yarn properties, just as with a normal light source.

[0072] According to an exemplary method sequence, in a first step, the reflectance value of the yarn can be detected starting from a defined time point during the spinning process. Then, in a further step, a reference value, in particular an average value from the measurement data over a defined length, can be formed. Based on this, in a further step, the formed average value, preferably the reference value, can be determined and frozen, in particular stored. Subsequently, in a further step, the reflectance value can be detected during the further spinning process, and a further average value can then be formed over a defined length, e.g., 100 meters. This allows a further comparison of the further average value with the reference value. This allows a further evaluation of the comparison. If a deviation is exceeded, measures such as stopping the spinning position can be initiated. It is particularly intended that the sensor and associated evaluation be based solely on the brightness signal in conjunction with the determined diameter and / or shading signal of the yarn. [Explanation of symbols]

[0073] 100 ways 101 Initialization 102 Receive 103 ratings 104 detection 105 generation 106 End 201 Lightness Value Curve 202 brightness value 203 Brightness Standard Value 204 Abscissa 205 Ordinate 301 Spinning Machine 302 Computer Programs 303 Computer-readable medium 304 Data processing devices 305 Control Device 306 Surveillance Devices 307 Suction 308 Spinneret 309a Artificial light source 309b LED 309c Infrared LED 310a First optical sensor 310b Second optical sensor 310c third optical sensor 311a First brightness sensor 311b Second brightness sensor 311c Third Light Sensor 312a first photodiode 312b Second photodiode 312c Third Photodiode 313 Thread 314 Yarn Clear 315a cable 315b additional cable 316 Measurement Chamber

Claims

1. A method (100) for detecting the formation of at least one weak point in a spun yarn, in particular an air-spun yarn (313), in a spinning machine (301), comprising: receiving (102) at least one detection value resulting from the optical detection of said thread (313), said at least one detection value being characteristic of the brightness of said thread (313); - evaluating (103) said at least one detection value in order to detect irregularities in the lightness of said thread (313); - detecting (104) said formation of said at least one weak point based on said detected irregularity.

2. said evaluation (103) of said at least one detected value - comparing said at least one detected value, in particular corresponding to a lightness value (202) of said yarn (313), with said at least one reference value, preferably a lightness reference value (203), in order to determine said irregularity based on the deviation of said at least one detected value from at least one reference value; 2. The method (100) according to claim 1, characterized in that the formation of the at least one weak point is preferably detected based on a quantitative evaluation of the deviation, preferably resulting in the at least one weak point being detected in the form of a structural defect in the yarn.

3. 3. The method (100) according to claim 2, characterized in that the irregularity with respect to the lightness of the yarn (313) is determined when at least one of the lightness values ​​(202) of the yarn (313) or a value derived therefrom is below at least one of the lightness reference values ​​(203).

4. said at least one detected value, in particular a brightness value (202), - a plurality of brightness values ​​(202), - lightness value curve (201), - change in brightness value, - the rate of change of brightness value, And preferably, said at least one reference value, in particular the brightness reference value (203), is - a plurality of brightness reference values ​​(203), - brightness reference curve, - change in brightness reference value, - the rate of change of the brightness reference value.

5. The method (100) according to any one of claims 1 to 4, characterized in that the at least one detected value, in particular the brightness value (202), corresponds to an average value, and preferably the at least one reference value, in particular the brightness reference value (203), corresponds to an average value.

6. 6. The method (100) according to any one of claims 1 to 5, characterized in that impurities of the yarn, in particular comprising foreign particles and / or foreign fibers, are taken into account during the evaluation (103) in order to compensate for the influence of the impurities on the at least one detected value, preferably, for this purpose, an impurity calibration is performed when spinning of the yarn (313) is stopped.

7. 7. The method (100) according to any one of claims 1 to 6, characterized in that the detection (104) of the formation of the at least one weak point is performed before complete formation of the at least one weak point, and the detection (104) of the formation of the at least one weak point is preferably performed in the form of detection of missing or incorrectly positioned wrapping fibers of the yarn (313).

8. The method (100) The method (100) according to any one of claims 1 to 7, characterized in that it further comprises a step of initiating a reaction to the detection (104) of the formation of the at least one weak point, for which purpose an output is generated when the formation of the at least one further weak point in the yarn (313) is detected, which triggers a cleaning, in particular a pneumatic cleaning, of the spinneret (308) of the spinneret (308) of the spinning machine (301), in particular after at least one pre-cleaning of the spinneret (308) or of the spinneret (308) of the spinning machine (301) and / or a termination (106) or interruption of the spinning process of the spinning machine (301) and / or a maintenance of the spinning machine (301), in particular after at least one pre-cleaning of the spinneret (308) or of the spinneret (308) of the spinning machine (301).

9. The method (100) further comprises the steps of: - defining the point in time of the spinning operation of said spinning machine (301) at which at least a first detection value, in particular in the form of a reflectance value of said yarn (313), is received; - defining the length of said thread (313) for which said at least first detection value is received; - starting said reception (102) of said at least first detection values ​​from said at least first detection values ​​received, preferably by averaging, to form said at least one reference value, starting from said defined point in time of the spinning process and for said defined length of said yarn (313); - initiating the reception (102) of said at least one further detection value, in particular repeatedly for said defined length or a further defined length of said yarn (313), in order to obtain, preferably by averaging, from said at least one further detection value for a further spinning process, at least one current detection value, 9. The method (100) according to any one of claims 2 to 8, characterized in that the detection (104) of the formation of the at least one weak point in the yarn (313) is performed based on a comparison of the current detection value with the at least one reference value, and the formation of the at least one weak point in the yarn (313) is preferably detected when the current detection value deviates from the reference value by a defined amount.

10. A device (304) for processing data, comprising means for carrying out the method (100) of any one of claims 1 to 9.

11. A monitoring device (306) comprising a device (304) for data processing according to claim 10, said monitoring device (306) being in particular a yarn clearer (314).

12. said monitoring device (306) comprising an artificial light source (309a), in particular an infrared light emitting diode (309c), for irradiating said thread (313) with light, in particular infrared light; 12. The monitoring device (306) of claim 11, characterized in that the monitoring device (306) comprises at least one or exactly one or two optical sensors (310a, 310b), preferably photodiodes (312a, 312b), in particular reflecting diodes, for detecting the light of the light source reflected by the thread (313), the diodes being arranged adjacent to the light source (309a), and that the monitoring device (306) comprises a third optical sensor (310c), preferably a third photodiode (312c), preferably arranged behind the thread (313) as seen from the light source (309a), for detecting shading resulting from the position of the light source (309a) and the thread (313) relative to the light of the light source (309a).

13. A spinning machine (301), in particular an air spinning machine, comprising at least one monitoring device (306) according to claim 11 or 12.

14. A computer program (302), the computer program (302) comprising commands that, when the computer program (302) is executed by a device (304) for data processing, a computer, cause the computer to perform a method (100) according to any one of claims 1 to 9.

15. A computer readable medium (303) having stored thereon a computer program (302) according to claim 14.

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