Title of Invention	METHOD OF PRODUCING COMPACTED YARN AND APPARATUS THEREFOR
Abstract	This invention relates to a method of producing compacted yarn characterized in that the effect of compaction is monitored by automatic checking of the hairiness of the generated yarn and by automatic monitoring of the exceeding of a predetermined hairiness threshold.

Full Text

The present invention relates to a method for producing a compacted yarn, especially for monitoring the functions of condensing or compressing the yarn. The invention also relates to an apparatus which can be used for such process. By a "condensed"or "compacted" yarn, one will understand a yarn in which, prior to the initial spinning or twisting of the fiber roving or sliver from which the finished yarn is to be fabricated by twisting, in which, as a rule, by means of an air stream trained toward the center of the fiber roving or sliver, projecting edge fibers will be laid back into the roving and packing density of the fibers themselves in the roving will be increased. This results especially in a reduction of the hairiness of the yarn produced as well as an increase in other quality parameters of the yarn, like improved binding of the fibers, increased utilization of the fiber material and enhanced strength of the yarn. The reference to "hairiness" of a yarn should be understood here to refer to the number of fibers which tend to project out from the yarn produced and the length to which the fibers project out of the yarn produced. A certain degree of hairiness is unavoidable with staple fiber yarns and for the textile products made from such yarns. Excessive hairiness is, however, undesirable. Excessive hairiness reduces the wear resistance of the yarn since the projecting fibers do not contribute to it. Hairiness can be the source of breakage of the projecting fibers from the yarn and thus a weight loss by the yarn as well as of excessive production of lint. The hairiness has a detrimental effect on the smoothness of textile fabrics produced from the yarn by weaving, knitting or the like. The projecting fibers have been removed in the past by, for example, singeing. As a consequence, significantly projecting fibers and large numbers of such projecting fibers should be avoided. To describe the hairiness, the projecting fibers are subdivided into length classes based upon their length in two millimeter units. In length classes up to 4 mm, the projecting fibers can be tolerable and may even be desirable for the textile character of the yarn and possibly even unavoidable. In the higher length classes of, for example 6 mm to 8 mm, the number of projecting fibers is significantly different between normally spun yarn and condensed spun yarn, the difference being so significant that the difference can delineate between normal and defective yarns. Condensed yarns can be made by directing the air stream transverse to the yarn at the outlet side of the outlet pair of rollers of a drafting frame, for example, of a ring-spinning machine and hence onto the fiber roving which emerges from the drafting frame with a given width of the band so that the fibers especially along the marginal regions of the roving are pressed back into the body of the roving. For the condensation of yarn or fiber rovings to be made into yarns, a variety of devices have become known. For example, hollow rollers having a perforated periphery with a row of small suction openings and maintained under suction, have been proposed. Flexible endless belts under suction can be formed with the perforations as well. The process and apparatus according to the invention are independent from the type of compaction or condensing device used and can be effected with different compacting or condensing devices. Such compacting or condensing devices operate in the manner which has been described to draw the projecting fibers back into the body of the roving. With such systems, however, the suction may fail or the suction effect at the periphery of the rollers of the condensing device may fail because of plugging of the suction pipes or of the suction passages or orifices. Suction belts can break. The fiber roving can shift laterally out of the effective range of the suction openings. Such defects frequently cannot be noticed at the spinning station and hence considerable lengths of yarn can be produced which are not compacted or condensed and thus can be defective. It is the principal object of the present invention, therefore, to provide a method of making a yarn whereby these drawbacks are avoided and long stretches of defective yarn are not produced as a result of the failure of a condensation or compaction operation. The object is achieved, in accordance with the invention in a method of producing a condensed yarn wherein the effect of the compaction is monitored by automatic detection of the hairiness of the yarn which is produced and controlling the process or the apparatus in response to the automatic monitoring of the hairiness so that crossing of a threshold representing a predetermined limiting value of the hairiness cannot occur. As a result of the monitoring of the hairiness and preventing the hairiness from exceeding a certain level, the negative effects of excessive hairiness which have been described can be avoided. Control via the single parameter not only allows all of the potential effects of excess hairiness to be eliminated but it allows adjustment to compensate for any failure of the condensation or compaction operation at the onset of such a failure and without waiting for the full adverse effects thereof. The invention has recognized that the effect of the compaction of a yarn or a roving acts preferentially on the projecting fibers with the greatest projecting length and a detection of the number of such fibers thus provides an especially clear indication of a defective condensation effect. Preferably the condensation effect is checked based upon the hairiness as determined by the longer projecting fibers and is monitored. Preferably it is possible to operate by checking the hairiness produced by the longer projecting fibers to determine a tolerable number of projecting fibers of, for example, the length range of 6 to 8 mm over a certain length so that when the count of such projecting fibers exceeds the resulting threshold, an error signal is triggered. An apparatus for detecting the hairiness of yarns is known and need not be described or illustrated in detail. The checking and monitoring of the hairiness can be carried out on the yarn itself or on the bobbin or cop to which the yarn is wound up since hairy yarn gives rise also to a hairy bobbin or cop. It has been found that the hairiness of a yarn on the cop provides a clearer indication because frequently fibers which are in the category of projecting fibers tend to be smoothed out by passage of the yarn through the traveler and only when subjected to centrifugal force at the high speeds of the bobbin or cop are they deflected outwardly and then become detectable. The latter rewinding of the yarn can also increase the detectable hairiness because of the reversal of the travel direction of the yarn which induces projecting fibers to stick out. The checking and monitoring of the yarns can also be effected at a variety of locations in the treatment of the yarn. Thus yarn can be checked for hairiness directly at the spinning station as it leaves the drafting frame, after being wound to form the cop or bobbin, or at some later point, for example, at a rewinding stage. The detection of the hairiness at the spinning station has the advantage that, should the condensation or compaction effect fail, this can be determined at the earliest stage and can be cured early in the production of the yarn. By monitoring the yarn at the spinning station itself, other arrangements of the type in which a yarn supplied to a spinning station may be removed, can be superfluous. Each working station can be equipped, according to the invention, with a hairiness sensor. Since the hairiness of the yarn tends to increase in the course of its processing, for example in passing through the traveler, because the centrifugal force or air current forces and the forces applied on winding up the yarn on the rotating bobbin or cop, upon reversal of travel direction in rewinding or the like, a monitoring in subsequent treatment stages can give rise to clearer or better results. The detection of the yarns at a subsequent treatment step for the yarn also has the advantage that the travel speed for the yarn is generally higher at all of these subsequent treatment locations than at the spinning station and hence the utilization of the apparatus can be increased in that a smaller number of monitoring units need be provided. The preferred subsequent station for monitoring is the station at which the yarn is rewound from the spinning cops or bobbins onto cross winding yarn packages or spools. The checking and monitoring of the yarns at the cop or bobbin can be effected advantageously in an apparatus which processes the cop or bobbin or into which the cop or bobbin is fed while the cop or bobbin is traveling past a hairiness sensor. A further advantageous possibility for checking or monitoring hairiness provides a hairiness check on the row of spinning or rewinding stations for the yarn or the cops or bobbins on the spindles of the ring-spinning machine, the sensor being moved past the cops or bobbins or the yarns along the spindle row. A single hairiness sensor can thus check or monitor a multiplicity of yarns or cops or bobbins. When it is determined that the compaction or condensing effect is missing or is not effective to the desired extent, the sensor outputs a signal which can be provided as an input to the manufacturing process. The signal can generate a warning or an alert, e.g. by an acoustic or visible signal which causes the intervention of service personnel. The signal itself, can trigger shutdown of the defectively working spinning station to suppress the fabrication of defective product. An apparatus according to the invention can have a hairiness sensor so configured that it outputs the length and number of projecting fibers by detecting only the number of projecting fibers of a minimum length and outputs a signal to the control unit. In a first case, the control unit is so configured that it sorts incoming fibers by length classification (in terms of length of the projecting fibers) and determines the frequency of occurrence of the fibers of minimum length. The control device is provided with means for detecting the crossing of a threshold for the number of projecting fibers in a given length class. When the checking and monitoring of the hairiness is carried out on yarn or on bobbins or cops at each spinning station or by a sensor which is moved past each spinning station, an error signal can be associated immediately with a given spinning station. However, when the checking and monitoring of the hairiness is carried out at a yarn processing machine which is downstream from the spinning frame and is separate therefrom, for example, at a rewinding machine or a further twisting or other machine using cops or bobbins which have been removed from the first-mentioned spinning machines, arrangements must be made to associate the particular cop or bobbin or the yarn therefrom with the particular spinning station from which the cop or bobbin arose. This can be accomplished by coding the yarn carrier, i.e. the core or bobbin tube or a carrier thereof with a code which indicates the spinning station so that it is possible to recognize the spinning station from which a defective yarn originates so that appropriate correction can be made. A system for this purpose is known, for example, from DE 36 03 002. The above and other objects, features, and advantages will become more readily apparent from the following description, reference being made to the accompanying drawing in which: FIG. 1 is a diagrammatic cross section through one side of a ring-spinning machine showing one of the stations thereof equipped according to the invention; FIG. 2 is a plan view of a spinning apparatus having a ring-spinning frame and a winding frame; and FIG. 3 is an elevational view showing a cop or bobbin on a plate provided with coded indicia. FIG. 1 shows the significant components of a ring- spinning machine 1 and including the roving bobbins 2 from which the rovings are drawn, a drafting frame 4 with three roller pairs 5, 6 and 7, and the ring-spinning frame 8 with its thread guide 9, a ring rail 10 with respective rings and travelers for each spindle 11 and the spindle rail 40 on which the spindles are mounted. Each spindle 11 can receive a sleeve 41 on which the cop 12 is wound. The cop 12 and its sleeve or tube 41 is placed onto the spindle 11 and the drive for the spindle 11 is found in the spindle rail 40. The ring-spinning apparatus 1 also comprises a roving stop device 13 which can be of conventional design. For example, the roving stop unit 13 can act on the lower roller of the input roller pair 5 of the drafting frame 4 and is represented by a half shell surrounding this lower roller. To interrupt the feed of the roving, the half shell on the lower roller can be pivoted so that the roving is no longer entrained between two rollers of the roller pair 5 and thus cannot advance through the drafting frame and will not be wound up into the cop 12. At the output of the drafting frame 4, each of the roving spinning stations can be provided with a condensing or compacting unit 14 in the form of a perforated lower roller 15 which is under suction and is juxtaposed with an upper roller 16. Other types of condensing or compaction units can be used as well and the invention is not dependent upon a compaction unit of any certain construction. Between the condensing or compaction unit 14 and the thread guide 9, the ring-spinning frame 8 is provided with a hairiness sensor 17 which is traversed by the yarn 18 and in which the hairiness of that yarn, as defined above, is detected. The hairiness sensor can be of a conventional design as well and need not be described further herein. The measured signal representing the hairiness of the yarn is fed by the sensor 17 via line 19 to a control device 20. In this control device 20, the input signal from the hairiness sensor is compared with a limiting value for the hairiness, i.e. the maximum permissible hairiness. This can be a measure of the number of projecting fibers in a certain length class, for example 6 mm to 8 mm. The hairiness sensor may thus be responsive only to outwardly projecting fibers of this length class or to fibers in a variety of length classes and the controller 20 can signal a hairiness level which exceeds the threshold and which, via the line 21 can trigger a control signal at the roving stop unit 13. To suppress further production of defective yarn, i.e. yarn with excessive hairiness, the controller 20 can operate the yarn feed shutoff 13 via line 21. The control device 20 can, instead of providing a control signal at 21, output via signal line 22 an alarm signal to a warning device, for example a warning lamp 23, which can alert a service person observing that lamp to the defect at the particular spinning station. The warning signal enables the service person to review the function of the condensing or compaction unit 14 and restore the latter to proper functioning. In the embodiment of FIG. 2, each working station 24 of a rewinding machine 25 in which the yarn 18 is rewound from a cop or bobbin onto a cross-wound yarn package is provided with a sensor A7 at each station. The measured value of this hairiness sensor 17 is fed to a bus system via a common line 26 connected to the control unit 20. In the control unit the measured value is compared with a predetermined limiting value or threshold as has been described. When this is exceeded, a warning signal is issued which can be observed by service personnel and the corresponding location or station 24 of the rewinding machine 25, at which defective yarn is found, can be shut down or corrected. When the ring-spinning machine 1 of FIG. 2 is provided with a transport device 27, the checking of the cops 12 for hairiness can be effected utilizing the transport device. Such a transport device can include an endless cable or other traction member 29 with entrainers by means of which the cop plates 30 are displaceable around the ring-spinning machine as part of the cop or bobbin replacement system. The plates can carry spindles 11 on which the core sleeves or device 41 for the cops can be fitted and from which the completed cop or bobbin can be removed. The checking of the cops for hairiness can be effected by a hairiness sensor, 17' positioned along the path of the cops which are displaced in the (direction of the arrow P. The sensor 17' can be connected to a controller 20 which can monitor the various spinning stations 24. Since the cop or bobbin plate 30 is provided with coded indicia 34 representing the station at which the cop or bobbin is formed, if the controller 20 detects a level of hairiness exceeding a predetermined threshold, because it can also identify the station from which the cop bearing the defective yarn arises, that station can be shut down. In that case, the control device 20, recognizing that the x-th cop is produced at the y-th spinning station, can signal for shut down of that spinning station. If the yarn is to be processed in a ring-spinning machine which has a winding or spooling machine 25 associated therewith, the cops 12 can be mounted at a transfer device 31 at an end of the ring-spinning machine 1 upon other cop plates 30 which, via a further transport device 32 can displace the cops to the work stations 24 of the package winder 25. The cop plates 30 of the package winder 25 return to the transfer device 31 after the cops have been emptied and can be supplied with fresh cops or fed to the transporter 21 of the ring-spinning machine to carry the empty core sleeve or tube thereto. The transfer device 31 is provided with a detector 33 which can read the data identifying the cop plates 30, namely, the bar codes 34 which can identify a particular spindle 11 of the ring-spinning machine from which the cop arises. The spindle number can also be retained in a data carrier or memory associated with the cop plate or affixed to the cop plate or to the sleeve of the cop and carrying electronically readable data. Upon detection of a defective yarn, that spinning station can be shut down until the condensing or compaction unit is repaired or replaced. This control can be effected automatically or the number of the station from which the defective yarn arises can be displayed so that an operator can shut down that station. The display for this purpose is provided on the controller at 42. The work station 24 of the package winding machine can be equipped with devices for reading the spindle number from the cop plate 30 or the cop sleeve or tube, to indicate the station at which the cop was formed. This gives the operator the possibility of monitoring the condensing or compaction device 14 at that station to eliminate any defects therein. It will be self-understood that it is also possible utilizing the controller 20, upon the generation of an error signal from the hairiness sensor 17' and detection of the spindle number, to generate an effector signal which is supplied to the ring-spinning machine 1 for automatic operation of the roving stop device 13 at the addressed station. Since defects in the compaction or condensing devices occur relatively infrequently, it is not necessary in many cases to monitor the traveling yarns of a yarn-producing or yarn-processing machine like a ring- spinning machine or a package-winding machine by respective hairiness sensors. A single hairiness sensor 17" can be provided on an endless member 35 as has been shown in FIG. 2 to move back and forth along a row of spindles, thereby repetitively monitoring cops for brief time intervals. An error signal can be generated where a defective yarn is detected and this signal can be associated with the address at which the defect is detected for shut down or correction. In FIG. 2 as well, a number of hairiness monitors at the package rewinding stations 24, have been shown thereby indicating that each of these stations can be monitored for hairiness as well. WE CLAIM: 1. A method of producing compacted yam characterized in that the effect of compaction is monitored by automatic checking of the hairiness of the generated yarn and by automatic monitoring of the exceeding of a predetermined threshold value of hairiness. 2. The method as claimed In claim 1 wherein the hairiness of the generated yarn is detected by the frequency of occurrence of projecting fibres of greater projecting lengths, 3. The method as claimed in claim 1 wherein the checking and monitoring of the hairiness is carried out on the yarn. 4. The method as claimed in claim 3 wherein the checking and monitoring of the hairiness is carried out directly at the spinning station. 5. The method as claimed in claim 3 wherein the checking and monitoring of the hairiness is carried out in a subsequent processing step for the yarn which is produced. 6. The method as claimed in claim 1 wherein the checking and monitoring of the hairiness is carried out on a cop into which the yarn is wound. 7. The method as claimed in claim 1 wherein upon overstepping of a predetermined threshold of hairiness, a signal is generated. 8. The method as claimed in claim 7 wherein the signal generated is used as a warning signal to cause notice of a developing failure. 9. The method as claimed in claim 7 wherein the signal automatically shuts down the defective spinning station. 10. An apparatus for producing compacted yarn characterized in that a hairiness sensor (17) for detecting the hairiness of a generated yarn (18) is connected to a control device (20) for determining the overstepping of a predetermined threshold of hairiness and which generates a signal upon overstepping of the threshold. 11. An apparatus as claimed in claim 10 wherein the hairiness sensor (17) detects projecting fibres of a certain length class of the generated yarn. 12. An apparatus as claimed in claim 10 wherein the control device (20) which detects overstepping of a predetermined threshold of hairiness, responds to the projecting fibres of certain length classes on the yarn (18) which is produced for the cop (12) wound therefrom. 13. An apparatus as claimed in claim 10 wherein control device (20) is operably connected with the spinning station of the apparatus (1) for producing compacted yarn and which is automatically shut down by means of a signal emitted by the control device at a defectively operated spinning station. 14. An apparatus as claimed in claim 10 wherein each spinning station of the apparatus (1) for producing compacted yarn is equipped with a hairiness sensor (17). 15. An apparatus as claimed in claim 10 wherein that a handling device (27) for a cop (12) is equipped with a hairiness sensor (17') operating upon successive cops which are handled by that device. 16. An apparatus as claimed in claim 10 wherein a yarn processing unit (25) equipped with at least one yarn sensor (17) is provided behind a device (1) for producing compacted yarn (18) and means (33,34,20) is provided which permits the association of the particular cop of compacted yarn with the particular spinning station of the apparatus. 17. An apparatus as claimed in claim 10 wherein along the work station (24) of a yarn-producing or yarn-processing apparatus (1,25) a hairiness sensor (17") is provided by means of which the yarns (18) or their cops (12) are successively and briefly sensed repetitively for their hairiness. This invention relates to a method of producing compacted yarn characterized in that the effect of compaction is monitored by automatic checking of the hairiness of the generated yarn and by automatic monitoring of the exceeding of a predetermined hairiness threshold.

Documents:

428-CAL-1999-(13-12-2011)-CORRESPONDENCE.pdf

428-CAL-1999-(13-12-2011)-PA-CERTIFIED COPIES.pdf

428-CAL-1999-FORM-27.pdf

428-cal-1999-granted-abstract.pdf

428-cal-1999-granted-claims.pdf

428-cal-1999-granted-correspondence.pdf

428-cal-1999-granted-description (complete).pdf

428-cal-1999-granted-drawings.pdf

428-cal-1999-granted-examination report.pdf

428-cal-1999-granted-form 1.pdf

428-cal-1999-granted-form 13.pdf

428-cal-1999-granted-form 18.pdf

428-cal-1999-granted-form 2.pdf

428-cal-1999-granted-form 3.pdf

428-cal-1999-granted-form 5.pdf

428-cal-1999-granted-pa.pdf

428-cal-1999-granted-priority document.pdf

428-cal-1999-granted-reply to examination report.pdf

428-cal-1999-granted-specification.pdf