WO2011027366A1

WO2011027366A1 - Yarn break monitoring system

Info

Publication number: WO2011027366A1
Application number: PCT/IN2010/000593
Authority: WO
Inventors: Krishnakumar Srivaikuntam Subbiah; Harsha Sunder
Original assignee: Krishnakumar Srivaikuntam Subbiah; Harsha Sunder
Priority date: 2009-09-07
Filing date: 2010-09-06
Publication date: 2011-03-10
Also published as: WO2011027366A4

Abstract

The present invention relates to a cost effective yarn breakage monitoring system and specifically relates to a reliable means and method of identifying yarn breaks in multi-spindle machines to alert human operators responsible for mending them on-time and in real time. More particularly, the present invention provides a system and method of identifying yarn breakage, involving a single scanning module (5) that traverses multiple machines, each comprising a plurality of spindles (6). Advantageously, in the present invention the workers are equipped with distributed client-devices to which the server in turn relays yarn breakage information and the workers responsible for that spindle are alerted to the problem of yarn breakage, to mend it at the earliest.

Description

YARN BREAK MONITORING SYSTEM

FIELD OF INVENTION

The present invention relates to a cost effective yarn breakage monitoring system and more specifically relates to a reliable means and method of identifying yarn breaks in multi-spindle machines to alert human operators responsible for mending them on-time and in real time. Advantageously, the present invention provides for a yarn breakage- monitoring system wherein the workers are equipped with distributed client-devices to which the server in turn relays yarn breakage information and the workers responsible for that spindle are alerted to the problem of yarn breakage, to mend it at the earliest.

DESCRIPTION OF PRIOR ART

Machinery used in the manufacture of yarn commonly involves large frames in which several spindles carry out identical operation in parallel. A single establishment where such activities are carried out - such as a spinning mill - typically involves numerous such frames. Due to inherent variability in the process, impacted in turn by a variety of operating conditions, the material being processed breaks at random. The incidence of this is often measured in terms of number of breaks per 100- spindle-hours.

Such breaks usually call for manual intervention to mend the break. Delay in mending the breaks adversely impacts the overall production. Delay also leads to wastage of valuable raw-material into which significant expenditure has been already invested in earlier stages of production. As a result, this represents a substantial loss even if the wasted raw-material is itself recovered and re-used.

In such establishments, a large work-force is employed to patrol the arrays of spindles and mend breaks at specific spindles whenever it is noticed. Most of the time of the workers is spent in patrolling and monitoring to identify specific instances of breaks, rather than in mending the breaks. However, reducing the work-force would lead to less frequent monitoring of each spindle, in turn increasing the average time elapsed before a break is mended. US 4280322 (Palitex project company GMBH, 1981) and US 4484376 (SKF Kugellagerfabriken GmbH, 1984) describe mechanisms that stop material feed when the yarn breaks, to reduce the waste on account of yarn breaks. This entails incorporation of a stop mechanism for each of the spindles, which is both expensive and maintenance- prone.

In another widely used solution offered by Uster Technologies AG, traveling sensors have been mounted on the ring rails, to detect traveler movement to identify yarn break. These sensors are in close proximity to the rings (~10mm away) to sense motion of the traveler. Hence, the stroke of movement of the traveling sensor is limited to the span of the machine. This arrangement also calls for specialized conveyor belt arrangement fixed close to the ring rail, to mount the sensor. Since each machine has two parallel rows of spindles, each ring frame needs two such sensing arrangements. The data is transmitted to a centralized computer. While this information is useful to the management to review the problem, it is not available to the shop-floor workers in real-time to ease their work load.

Elsewhere in US 4254613 (Shinzo Kitamura, 1981), piezo-electric sensors have been mounted on the lappet (an eyelet through which the yarn passes), to sense breakage by means of the vibration it introduces. Apart from requiring elaborate wiring, connecting sensors on each spindle, more effort is required to maintain this system than to keep the ring frame funning.

US 4341958 (Shiuji Qhsawa, 1982) and US 4888944 (Zellweger Uster AG, 1989) describe systems involving optical sensors. These require hardware changes to be carried out on the machine.

US 6536643 disclose a yarn breakage position detection method and device which can detect a yarn breakage occurrence position when a running yarn is broken in a variety of textile machines and textile manufacturing processes. US3648027 relates to monitoring systems for use with yarn winders which monitors and totalizes the performance of each bobbin-cone or spindle unit in an effort to pin-point mechanical malfunctions, operator ineffectiveness and defective yarn running conditions and provides the maintenance and supervisory staff with valuable process information. US7110846 relates to a yarn processing system and yarn feeding device for controlling and/or treating and/or monitoring and/or scanning the yarn, said yarn feeding device having a computerized control device.

US 3968637 relates to an apparatus for detecting a yarn break by means of a tribo- electrical noise signal, having at least one yarn processing position where the transport of the yarn is to be monitored, which includes a signal generator and a signal detection circuit operatively associated with each yarn processing position which monitors yarn breaks at a plurality of yarn processing positions of the textile machine. All of these methods involve one sensor dedicated to sensing each strand of yarn in the machine. In typical machines involving a plurality of strands of yarn processed simultaneously in a large number of yarn-processing locations such as spindles; this increases the cost and complexity of the system. US 3,099,829 (1963) describes a system in which travelling electromagnetic or photosensor triggers audible or visual alarm when 'any' yarn break is detected. US 3523413 discloses a traveling photo-sensor for detecting the ends down condition of textile yarn forming machines and reporting it by displaying it on a central TV screen. In both these methods, the sensor is mounted on the overhead traveling cleaners traversing multiple machines. Both of the methods seek to alert workers to the incidence of breaks. The first of these only gives a general alarm without specifying the location of the break, and is hence of little use to the workers on the floor. The second represents an improvement in this regard, but it is not practical for the workers to assemble at one (or a few) locations to view a TV screen in a context where they are distributed across different places in the shop-floor attending to different responsibilities related to overseeing of many machines.

Further, the movement of the overhead traveling cleaner is typically jerky, swaying and of non-uniform speed, its path of travel being about a meter away from the yarn-strands being monitored. The kind of sensors described in these two patents would perform highly unreliably in such an environment.

Thus, there is no system of yarn-break monitoring in spinning frames that is simple, cost- effective, and reliable and does not call for extensive modifications to the machines. Importantly, no breakage-monitoring system has addressed the issue of making available this information in real-time to workers distributed across the production-floor.

It will be understood that the term "yarn" is used in a generic sense to include all multi- fiber groups such as slivers as well as individual threads, filaments and like materials made of fibers.

The availability of a cost-effective and reliable means of monitoring breaks and notifying workers of the location of the break would lead to enhanced worker productivity and reduced worker fatigue. It would also enable the management to save costs by increasing the number of spindles allocated per worker. This is significant because the expenditure on account of salary to the workforce engaged in patrolling for breaks is comparable to the net profit of the entire establishment. Any savings in this cost-component would therefore have a significant impact on profitability.

OBJECT OF THE INVENTION

It is the primary object of the present invention to provide for a system and method of identifying yarn breakage, involving a single scanning module that traverses multiple machines, each comprising a plurality of spindles. It is yet another object of the present invention to provide for a system and method to alert relevant human operators when there is yarn breakage, with adequate information about the location of the break to enable them to attend to it expeditiously.

It is another object of the invention to provide for a system and method for a yarn breakage momtonng system wherein, the infrastructure existing in the establishment is used to achieve the traveling motion of the scanner and to provide power and communication links to the scanner.

It is another object of the present invention to configure the worker-side client-devices in a number of combinations to suit the context of operation, including:

• Fixed devices as well as hand-held devices

• Wired communication line as well as wireless communication with the server

• Driven by external power as well as. built-in battery

• Alpha-numeric display as well as graphical user interface

It is another object of the present invention to make the system deployable in a number of different production processes that call for the monitoring of arrays of spindles including (but not limited to) simplex frame, ring frame, Two-for-one twister (TFO) and ring- doublers.

SUMMARY OF INVENTION

Thus according to the basic aspect of the present invention there is provided a system for continuous monitoring of yarn-breaks in multi-spindle machines in real time comprising: at least one scanning module with sensing device; and

a communicating device,

wherein the said scanning module is used to monitor multiple spindles,

wherein the said sensing device is a camera integrated with image processing system, wherein the said image-processing system is capable of recognizing -the occurrence and location of yarn-breaks from the images captured,

wherein the said communicating device enables the scanning module to communicate information about yarn-break to a computer or like device in real-time, and wherein the path of travel of said scanning module is positioned sufficiently away from the yarn strands being monitored, to enable it to freely scan multiple machines comprising a plurality of strand processing stations each.

It is another aspect of the present invention, wherein the said camera is mounted on the carriage of the existing overhead traveling cleaner of the machine.

It is another aspect of the present invention, wherein machine-recognizable indicia are provided on the dark/matte background surface of the machine behind the position where the yarn is being sensed, to enhance reliable interpretation of signals when the scanner moves in a swaying, jerky or otherwise non-uniform way.

It is another aspect of the present invention, wherein the said communication lines are wired or wireless.

In accordance with another aspect of the present invention there is provided a system for transmitting information on yarn-breaks, captured by one or more sensing devices in realtime to a server, wherein the said server relays said yarn breakage information to at least one client device that is accessible to the worker(s) responsible for mending the break.

In the above said system, the said client devices are hand held devices including computers, smart-phones and other such devices capable of remote communication and textual or graphical display, or audio output or tactile signals.

It is another aspect of the present invention, wherein the said client device is used by the worker to notify status to the server when the yarn-break is attended to.

In accordance with another aspect of the present invention there is provided a system, wherein the information received from time to time by the server is aggregated in a database to analyze performance of the machines and the performance of the workers assigned to mend the yarn-breaks. A further aspect of the present invention relates to a method of continuous monitoring of yarn-breaks in the above said system comprising:

monitor arrays of spindles for yarn-breaks;

occurrence and location of yarn break is communicated in real-time to workers responsible for mending the break;

workers are enabled to communicate status of yarn break after it is attended to;

status is independently reconfirmed by monitoring means;

records of instances of yarn break, location of the break, time when it was identified, time when it was attended to, identity of the worker who attended to it, status after being attended and like details are stored in a database; and

data is analyzed with regard to one or more of the frequency of breaks, duration for which a break is unattended, specific spindles where incidence of breaks is higher, workload on workers, their response time or other parameters.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 : Illustrates the yarn breakage-monitoring system of the present invention.

Figure 2: Illustrates the logical flow of continuous monitoring of yarn-breaks in the system of the present invention.

DETAILED DESCRIPTION OF THE INVENTION WITH REFRENCE TO THE ACCOMPANYING DRAWING

As stated above, the present invention provides for a system and method of identifying yarn breaks in spindles, especially across a plurality of multi-spindle machines. The invention also involves a system and method for communicating this information in realtime to alert human operators when there is a yarn breakage.

The invention envisages a solution that is independent of the construction of the specific machines being monitored, to be implementable with minimum alteration or modification of the legacy installations. Accordingly, this invention involves the mounting of a sensing module on a travelling path contiguous to the rows of spindles, traversing the chosen arrays of spindles across a plurality of spindles along pre-determined paths that do not interfere with parts of the machines themselves. Similar traveling arrangements have been proposed in the prior art, for instance, in US 3,304,571 to convey a suspended cleaner past rows of spindles across multiple machines. Where such conveying means are already present, the proposed sensing module may be readily mounted on these and the power and communication lines for this may be drawn along the paths already available.

While it has been proposed in the prior art that a sensor be mounted on the traveling carriage of an OTC (Overhead Traveling Cleaner) to sense breaks, such systems have not been deployed widely because of poor reliability. These limitations come from the fineness of the yarn strands being sensed, which could be as small as 0.1mm in diameter, in relation to the distance at which the sensor is positioned, which is over a meter away. Thus, sensing of yarn involves a resolution that is ten-thousandth of the distance of the object being sensed. Conventional on-off (digital) sensors like the ones proposed in the cited patents are typically not capable of this.

The problems of sensing are further aggravated by the fact that the yarn strands themselves are not stationary, but vibrating as they are processed at high speeds that could be of the order of tens of thousands of revolutions per minute. In addition, the motion of the carriage on which the traveling sensor is mounted is not very even, and the suspending arrangement is prone to swaying and jerky motion. Even if a break in yarn is detected, it is very difficult to know the precise location (spindle) where the break has occurred.

The present invention proposes to overcome these limitations by the use of a camera that involves thousands (or millions) of sensors arranged in a two-dimensional array. Each sensor captures a picture element (pixel), and the array of pixels adds up into a complete image. While cameras involving high resolution are available, these are generally more expensive. It is more advantageous to use optical arrangements, such as those involving a plurality of lenses, to 'bring the objects closer', thereby magnifying them. Alternatively, any of the known systems of magnifying the image using software may be used. While a number of methods are used in commercially available off-the-shelf devices, the interested reader may refer to US 7,202,888 and US 5,231,519 which describe specific methods of achieving this.

Numerous cameras and other optical appliances are commercially available, that incorporate features that compensate for shake of the camera. Typically, these involve motion-sensing transducers and negative-feedback of sensed motion to compensate. US 5.768,016 and US 5,387,999 are illustrative of this approach.

The traveling camera in the present invention would capture images at distinct instants of time so that successive frames capture advancing sets of spindles traversed by the movement. While blurring of images due to shake of camera can be compensated as described above, uneven speed and orientation of the camera makes it difficult to identify the exact position of the yarn (or yarn-break) that is being captured on the image. It is proposed to overcome this limitation by ensuring that successive images are formed by overlapping frames, so that by the overlapping (common) areas of successive images, a larger continuous image is "stitched" together. Techniques of achieving this are well known to any person familiar with the prior art. The attention of the reader is drawn to US 5,611,033, US 6,104,840 and US 7,184,091 as illustrations of this.

The machines generally have a dark or matte background behind the yarn strands being monitored for breaks, as these facilitate human operators patrolling to monitor the spindles. It is advantageous to mark this surface with machine-readable indicia that are captured in the camera images. This will facilitate the stitching together of successive images to create a composite image, thereby ensuring that the location of a yarn-break is identified without error.

While the foregoing discussion outlines an economical and effective way of identifying yarn-breaks in multi-spindle machines, this knowledge is most useful if it is available in real-time to the workers responsible for mending it. Irrespective of how yarn-break is detected, communicating real-time information on yarn-breaks to the workforce that is typically distributed across the production floor brings powerful economies in the operational cost, while simultaneously reducing the fatigue of the workers.

Conventionally, about 60% of the total work-force is employed in patrolling the spindles for yarn-breaks and mending them when detected. Although a very small portion of their time is devoted to actually mending the breaks, the numbers employed is derived from the frequency with which any spindle has to be monitored. A longer interval between two successive passes of an operator would lead to longer duration for which the break is unattended, and hence more wastage of raw-material and loss of production. In this context, the fact that a typical OTC travels about eight-times faster than a worker represents a significant opportunity to reduce the size of the work-force. However, to realize this opportunity, the reduced workforce should be immediately alerted to the incidence and location of yarn break as soon as it is detected.

Most systems involving sensors that monitor yarn-breaks store the information in a database for subsequent integration into an MIS (Management Information System). While this has its uses, it does not serve the purpose described above. The instances where information is sought to be made available to workers are often not practically useful to a workforce that is scattered at different places, attending to different machines. For instance, US 3,523,413 proposed a system where information about the status of all spindles is displayed on a TV at a fixed location.

To overcome these limitations and make real-time information on yarn-breaks available to workers, it is proposed to aggregate information from the sensing module(s) in a server, and from there relay it to hand-held devices held by workers charged with the responsibility of mending the breaks. While the aggregation of information from the sensing modules) may be by means of wired or wireless link, the dissemination of this information to targeted workers is best done through wireless links. This may be done through general cell-phone connection protocols like GSM/GPRS or specific local wireless networks like Zigbee. Reference is now invited to the accompanying Figure 1, which illustrates the yarn breakage-monitoring system of the present invention. The system according to the present invention comprises server (1); client device (2); and at least one scanning module (5) with sensing device, which is a travelling sensor. More particularly, the sensor is a camera with image processing capabilities. The yarn-break information is transmitted from the camera in real time to the server (1). The workers (3) are equipped with distributed client-devices (2) which are hand held computers. The server (1) then transmits yarn breakage information to the client device (2). Importantly, the sensor is required to be positioned about 1 -meter away from the rows of spindles (6) being scanned, in order to not interfere with parts of the machine during its traverse. The sensor may be mounted on the carriage (4) of the overhead traveling cleaners (OTCs) or like guide-ways and the power and communication lines are routed along the same cables / cable-ducts that serve the OTCs. This existing infrastructure is advantageously used to establish the traveling motion of the scanning sensor module (5) and to establish power and communication links to it.

The spinners charged with the responsibility of mending yarn breaks or 'creeling up' when input sliver runs out are equipped with hand-held devices that textually or graphically display the location of spindle where yarn-break has occurred in real-time (with suitable audible or tactile alerts), the information about yarn-break being captured from any suitable system of sensors.

When the break is mended by a worker (3) responsible for that spindle, a return communication path is also provided, by which the worker communicates the successful mending of the yarn-break back to the server (1) using the client device (2); The server is enabled to capture information regarding the duration for which a break is unattended - which the management may use, to optimize worker (3) productivity and size of the workforce. The mending of the break is subsequently confirmed by monitoring the spindle during the next pass of the scanner (5) and relaying information about the status of that spindle from the scanner to the server (1). Advantageously, in the system, there is provision for spinner to update information through the same device when yarn-break is mended, or if the spinner needs assistance or needs to stop the machine.

The worker-side client-devices may be configured in any number of ways to suit the context of operation like:

· Fixed devices as well as hand-held devices

• Wired communication line as well as wireless communication with the server

• Driven by external power as well as built-in battery

• Alpha-numeric display as well as graphical user interface The system is deployable in a number of different production processes that call for the monitoring of arrays of spindles including (but not limited to) simplex frame, ring frame, Two-for-one twister (TFO) and ring-doublers.

Claims

I CLAIM:

1. A system for continuous monitoring of yarn-breaks in multi-spindle machines in real time comprising:

at least one scanning module (5) with sensing device; and

a communicating device,

wherein the said scanning module (5) is used to monitor multiple spindles (6), wherein the said sensing device is a camera integrated with image processing system, wherein the said image-processing system is capable of recognizing the occurrence and location of yarn-breaks from the images captured,

wherein the said communicating device enables the scanning module (5) to communicate information about yarn-break to a computer or like device in real-time, and

wherein the path of travel of said scanning module (5) is positioned sufficiently away from the yarn strands being monitored, to enable it to freely scan multiple machines comprising a plurality of strand processing stations each.

2. A system as claimed in claim 1, wherein the said camera is mounted on the carriage (4) of the existing overhead traveling cleaner of the machine.

3. A system as claimed in claim 1, wherein machine-recognizable indicia are provided on the dark/matte background surface of the machine behind the position where the yarn is being sensed, to enhance reliable interpretation of signals when the scanner (5) moves in a swaying, jerky or otherwise non-uniform way.

4. A system claimed in claim 1, wherein the said communication lines are wired or wireless.

5. A system for transmitting information on yarn-breaks, captured by one or more sensing devices in real-time to a server (1), wherein the said server relays said yarn breakage information to at least one client device (2) that is accessible to the worker(s) (3) responsible for mending the break.

6. A system as claimed in claim 5, wherein the said client devices (2) are hand held devices including computers, smart-phones and other such devices capable of remote communication and textual or graphical display, or audio output or tactile signals.

7. A system as claimed in claim 6, wherein the said client device (2) is used by the worker (3) to notify status to the server (1) when the yarn-break is attended to.

8. A system as claimed in claim 5, wherein the information received from time to time by the server (1) is aggregated in a database to analyze performance of the machines and the performance of the workers (3) assigned to mend the yarn-breaks.

9. A method of continuous monitoring of yarn-breaks in the system as claimed in anyone of claims 1 to 8 comprising

monitor arrays of spindles (6) for yarn-breaks;

occurrence and location of yarn break is communicated in real-time to workers (3) responsible for mending the break;

workers (3) are enabled to communicate status of yarn break after it is attended to;

status is independently reconfirmed by monitoring means;

records of instances of yarn break, location of the break, time when it was identified, time when it was attended to, identity of the worker (3) who attended to it, status after being attended and like details are stored in a database; and