Title of Invention

A DEVICE FOR MEASURING THE QUALITY OF FIBERS AND A METHOD FOR OBTAINING DEFECT FREE ROVING.

Abstract

THE INVENTION DISCLOSED MAKES IT POSSIBLE TO MONITOR AND ANALYZE THE MOST IMPORTANT FIBER QUALITY PARAMETERS SUCH AS THICKNESS, DISTRIBUTION OF THICKNESS OVER THE LENGTH, PERIODICAL FAULTS AND OTHERS IN REAL TIME BY MEANS OF REGISTRATION OF THE PARAMETERS INFLUENCING THE PRODUCTION PROCESS BY MEANS OF SENSORS AND LEADING THEM TO A SUITABLE ANALYZING UNIT. A DEVICE FOR EXTRACTING DEFECTIVE ROVING (BOBBIN) OUT OF A MULTITUDE OF SIMULTANEOUS ROVING PROCESSES, COMPRISING : A MODULE FOR PERIODICALLY OR CONTINUOUSLY GENERATING MEASURED VALUES OF EACH OF SAID SIMULTANEOUS ROVING PROCESSES; A MODULE FOR DYNAMICALLY CALCULATING A REFERENCE VALUE FROM AT LEAST ONE OF SAID MEASURED VALUES; A MODULE FOR COMPARING EACH OF SAID MEASURED VALUES WITH SAID REFERENCE VALUE; A MODULE FOR SENDING AND/OR DISPLAYING A SEPARATION SIGNAL BY WHICH DEFECTIVE ROVINGS ARE SEPARATED; AND, MEANS SUCH AS SENSORS (1.1 TO 1.8), AT MULTIPLE PRODUCTION POSITIONS, FOR SENSING RELEVANT MATERIAL PARAMETERS SUCH AS QUALITY AND VOLUME OF FIBER MATERIAL, AND FOR ANALYZING THE INFORMATION, THUS OBTAINED, BY COMPARING THE RESULTS TESTED AT VARIOUS POINTS IN TIME WITHIN A SINGLE PROCESS, INORDER TO DETERMINE PARAMETERS SUCH AS HEREIN DESCRIBED.

Full Text

The present invention relates to a device and method for extracting defective roving (bobbin) out of a multitude of simultaneous roving processes. When fibers are processed into yarn by means of a spinning process the quality of the end product is significantly influenced by the process parameters. In a spinning process a sliver is drafted by which a roving is created. This is followed by the actual spinning in the ring spinning frame is which the roving is drafted, twisted and wound. A continuous monitoring of the creating of the roving which does not influence the process is not known. The processing of the sliver, which is rolled up loosely in cylindrical cans, into roving is a particularly critical process which is particularly substantial for the quality of the end product. The technical challenge of the transformation of the sliver into yarn by drafting and finally twisting lies in keeping the drafting force exerted on the sliver such that the thickness of the yarn resulting after spinning is constant. Because the process in question is continuous and proceeds at high speed with a medium (sliver/yarn) of quasi endless length it is unfavorable (practice according to the state of the art) to extract samples for measurement as the machine must be set back for this purpose. Mechanical interference in the process is in any case unfavorable because the small mechanical strength of the sliver and the not yet twisted yarn make it practically impossible. Up to now an online monitoring of roving for the most important quality parameters such as thickness (especially hank), distribution of thickness over length (especially unevenness, cut length, roving stretch, hank variation) and/or periodic faults and others was not possible concerning the processing of fibers. The normal procedure today is to take samples of roving out of the production process and examine them in the laboratory. This practice however has various significant disadvantages. The largest disadvantage is the considerable length of time that passes until the results of the analysis are available because the machine either continues to work or stands still during this time. If any fault is discovered, a lot of material and/or a lot of time is lost. This means that correcting measures are only possible at a later time. Besides, only the monitoring of one roving process is possible. Normally, however, more than one hundred roving stations are operated in parallel in one machine. Thus there is an obvious need for a method and a device which makes possible a monitoring of the roving which is as constant as possible, reliable and moderate in cost and which can operate without interference or even interruption of the production process. Optical or mechanical sensor systems comprise different disadvantages for monitoring quality parameters such as thickness, distribution of thickness over the length, periodical faults and others. Thickness measurements with only one optical sensor do not yield satisfactory results since the material to be measured generally does not have a cylindrical cross section. For reliable optical thickness measurements, more than one optical sensor measuring in different directions are required. Measurement devices which mechanically act on the material to be measured cannot be used practically due to the sensitivity of the fibers in the processing stage. It is an object of the present invention to solve the problems of facilities according to the state of the art with a method and a device which especially works simply, precisely and at moderate cost and, if desired, is also suited to be integrated into existing facilities. Occurring faults are to be detected as quickly as possible. The measurement results generated by means of the facility are on the one hand suitable for detecting problems and representing them visually and on the other hand for the independent correction of the parameters influencing the roving process. The stability of the system is to guarantee the simplicity of the device. Accordingly, the present invention provides a device for extracting defective roving (bobbin) out of a multitude of simultaneous roving processes, comprises : a module for periodically or continuously generating measured values of each of said simultaneous roving processes ; a module for dynamically calculating a reference value from at least one of said measured values ; a module for comparing each of said measured values with said reference value ; a module for sending and/or displaying a separation signal by which defective rovings are separated ; and, means such as sensors (1.1 to 1.8), at multiple production positions, for sensing relevant material parameters such as quality and volume of fiber material, and for analyzing the information, thus obtained, by comparing the results tested at various points in time within a single process, in order to determine parameters such as herein described. The device may have a module for sending and/or displaying information for localizing said defective rovings and/or information about the degree of deviation from said reference value and/or a module for calculating said reference value from a representative subensemble of said measuring values. The composition of said subensemble is changed periodically or non-periodically with time. The preliminary reference values are calculated from at least two subgroups, each subgroup consisting of a selection of said measured values, said preliminary reference values are compared with each other, and the measured values forming a subgroup are excluded from calculating said reference value if the preliminary reference value from said subgroup deviates from another preliminary reference value by a defined deviation. The device may have a module for automatically eliminating said roving processes after receiving said separation signal. Said measured values are selected from the group consisting of thickness, especially hank ; distribution of thickness over length, especially unevenness, cut length, roving stretch, hank variation ; and/or periodic faults of said roving process. The device may have a module for calculating a statistical distribution from said measured values and for subsequently evaluating, classifying and, if desired, saving in a library statistical characteristics of said distribution. Environmental influences are compensated by evaluating and comparing said measured values with said reference value. The device may have a module for a periodical or continuous generation of measuring values within one roving process. Said sensor measures the fiber mass and said sensor is a capacitive sensor. The device comprises a processing unit, which serves to control a drafting mechanism, and a servo unit standing in a functional connection with said processing unit. The invention also provides a method for extracting defective roving (bobbin) out of a multitude of simultaneous roving processes, comprising the steps of: periodically or continuously generating measured values for each of said simultaneous roving processes ; dynamically calculating a reference value from at least one of said measured values ; comparing each of said measured values with said reference value ; sending and/or displaying a separation signal by which defective rovings are separated ; sensing and analyzing the information thus obtained by comparing the results tested at various points in time within a single process ; and, obtaining defect-free roving (bobbin) out of defective roving, so extracted. The invention disclosed makes it possible for the first time to monitor and analyze the most important quality parameters such as thickness (hank, etc.), distribution of thickness over the length (unevenness %, cut length CV %, roving stretch, hank variation, etc.), periodical faults and others in real time by means of registration of the parameters influencing the production process by means of sensors and leading them to a suitable analyzing unit. The invention disclosed preferably monitors the relevant material parameters by means of capacitive sensors. These have the characteristics that they determine the volume of the fiber material and thus do not depend on its form and arrangement. Furthermore these sensors react in a very short time which, even with the very fast processes in question, allows a sufficiently fast registration of all relevant and interesting parameters. Because the fibers to be processed are in general natural products it is important that their characteristics which vary with changing environmental conditions are taken into consideration. Especially varying temperatures and air humidity must be taken into consideration. Even the advantageously used capacitive sensors are subject to certain environmental influences. These can be taken into consideration by a corresponding additional installation in the process in order to compensate a possible drift of the facility. This kind of solution however is relatively complicated and subject to disturbances. The invention disclosed here solves this problem in a very elegant, superior way. Because in any case many equal processes (normally more than one hundred) run in parallel and generally each of these is inventively monitored online a simple but all the same convincing advantage of this invention is that it takes advantage of this plurality. For this purpose a starting condition is determined in which the parameters of a choice of relevant parallel processes (of a subgroup) are determined to serve as reference. Then the statistic distribution of a relevant subgroup which is however constantly acquired and updated is considered and compared with the considered stations such that possibly occurring outliers can be detected immediately and if desired represented graphically and removed. Furthermore the statistical distribution of all measured values is determined from the subgroups which constantly change in their assembly in time. This constantly changing distribution curve is compared to experimental values stored in a library which serve for the determination of unusual conditions. If the environmental conditions change for all observed stations this has no influence on the detection of outliers as the reference value and its statistical distribution on average changes regularly for all parallel processes and the arrangement gets along without additional sensors. Naturally additional parameters can be taken into consideration if required. The facility, however, is kept in an inherently stable condition by its inventive arrangement which condition takes advantage of the availability of the measured values of a relevant subgroup or all processes running parallel in an aimed manner. Thus unwanted deviations can be eliminated manually or by means of a suitable control circuit. The registered data is represented graphically and analyzed statistically such that it serves in helping making decisions for the management and as data source for the course of the process. DESCRIPTION OF THE ACCOMPANYING DRAWINGS The inventive functional principle and examples of embodiments are explained in more detail in connection with the following figures by means of examples and diagrams. The invention is however not restricted to such embodiments but can, if desired, be extended to similar applications. Fig. 1 shows a possible distribution curve of measured values. Fig. 2 shows a possible distribution curve of displaced and unwanted measured values. Fig. 3 shows a schematic representation of a roving facility. Fig. 4 shows a capacitive sensor and a drafting mechanism in a three- dimensional view. Fig. 5 shows a capacitive sensor and a drafting mechanism in a two- dimensional view. Fig. 6 shows eight coupled sensors with a measuring box in a three- dimensional view. Fig. 7 shows a capacitive sensor and a drafting mechanism in a three- dimensional view. Figure 1 shows a possible statistic distribution of a relevant amount of measured values which is determined from a subgroup of considered sensor values. The abscise X diagrammatically shows the actual deviation from a determined starting value (here, e.g., zero) and the ordinate Y shows the occurrence of the sensor values. The distribution of the measured values over the observed sensor values is made clear by curve K. The facility described here is adjusted such that the mean value M of all observed measured results is at a deviation X from zero. This curve is a reference for the other sensors. Measured values which are within a defined bandwidth B fulfill the desired quality prescriptions. The values outside are indicated, examined and possibly corrected or sorted out. The determined reference data is in general compared to stored data from a database. In this manner dangerous conditions can be additionally recognized and impeded. Figure 2 shows the effect of a drifting of the facility. If the measured values of all the sensors observed for the forming of reference change due to changed environmental influences, this has no influence on the determination of outliers. Due to a drifting of the facility the measured values are displaced in this case, the mean value and distribution are displaced evenly, as shown by arrow D in Figure 2. Mean value M and distribution curve K are as before, still references relatively to which the measured values are compared although these have been displaced due to drifting. The band width B of the tolerable measured values is also determined relatively to mean value M and from experimental values stored in a library. A further important value for judging the process is the form of distribution curve K. If this curve deviates considerably from the experimental values Stored in a library, which is exemplified by means of curve K* the process must also be examined. This kind of unwanted form of distribution curve K* can be caused by measured values from one part of the facility which deviate from the norm. For this reason it is sensible to determine the reference values at a lower level of the facility. Thus regions with problems can be determined and turned off faster by which the monitoring process of the facility is spared of unwanted measured values. The measured values and the determined reference values are, if required, stored in a library such that they are available for the later finding of a decision. Considering these observations it becomes obvious that the facility advantageously references concerning its own mean value M and experimental values and thus has an inherent stability which cannot be brought out of balance by changing influences. Due to this stabilization referring to the mean value and the experimental values and the modular design of the facility a compensation of the sensor drifting and a processing true to time of all relevant measured values is actually possible. Figure 3 diagrammatically shows a preferred design of a roving facility. The basic modules 6.1 to 6.8 consisting of a collector-circuit-module control unit 5 (termed CCM control unit in the following) and eight sensors 1.1 to 1.8 can be seen. (The CCM control unit and the sensors are not numbered in Fig. 3 in order to allow a better general view. For further details of a basic module 6.1 to 6.8, cf. Fig. 6.) Individual basic modules 6.1 to 6.8 are connected to each other and to a machine-processing station 25 (termed MP station in the following) by means of data transfer lines 20. The energy supply of all elements can be simultaneously guaranteed via the data transfer lines 20. An MP station typically receives the data of fifteen CCM control units 5. Different MP stations 25.1 to 25.5 are connected in succession and connected to a central processing unit 26. The central processing unit 26 can again register and analyze the data of several such chains of MP stations 25. With the preferred embodiment shown here the data of all sensors 1 is registered and analyzed. The modular design of the facility with its preferred branched design makes it possible to maintain control over complex facilities. Environmental influences which possibly change and the drift of the facility generally create the necessity for additional sensors and correcting variables in order to compensate these changes. With the inventively combined, modular design shown here no additional measured values are required. Naturally it is possible to take additional values into account if required. The facility, however, is in general inventively inherently stable. Because the object is to detect outliers it is sufficient to use measured data of a relevant subgroup of sensors, which however constantly may change its composition, to form a reference value and a reference distribution. The forming of reference data is advantageously carried out centrally on the level of a central processing unit 26. In order not to distort the reference value when a problematic condition is on hand it is useful, with larger facilities, to determine reference values on lower levels, e.g. on the level of the MP stations 25 such that this branch can be switched off when the reference data deviates considerably from norm such that negative influences do not spread into the whole facility. It can be presumed that even when the measured results drift due to changing environmental influences which act on the sensors or the electronics this does not cause problems. Even though the drift varies from sensor to sensor in a random manner, the statistical drift of each individual sensor corresponds to the statistical drift of all sensors. Due to this circumstance the facility generally does not require additional measured values as it references and stabilizes itself relatively to a mean value determined from its own statistical data. Thus it is also guaranteed that even at very high processing speeds a precise registration and analysis of all measured values is guaranteed. A further advantage of this modular inherently stable design is that the facility is especially suitable for combination with existing facilities as no modification of the facility is required. The arrangement according to the invention is not only able to find outliers between the single roving processes, it is also suitable to identify outliers within each roving process by comparing the results tested at various points in time within a single process. This will help determine parameters such as unevenness, cut length, roving stretch, hank variation and periodic faults. Figure 4 shows a capacitive sensor 1 advantageously consisting of two sensor plates 10.1 and 10.2 for the measurement of the capacity and a casing 11, which is for fixing of the sensor (not shown in detail here) and contains sensor electronics (not shown in detail). Via a connecting cable 12 sensor 1 is supplied with energy, monitored and measured data is transmitted. Roving 3 is moved in the direction indicated by arrow P through a measuring field 13 which is between the two sensor plates 10.1 and 10.2. The roving 13 influences measuring field 13 in dependence of the volume of fibers located in measuring field 13. The thus caused change in measuring field 13 is registered and fed into analysis via connecting cable 12. A CCM control unit is for control, monitoring and registration of the measured data from sensor 1 and if necessary of a drafting mechanism 2. It is connected with other components via a connecting cable 19. The roving 3 is pulled through rolls 15.1 and 15.2 in the direction indicated by arrow P. By means of drafting mechanism 2, consisting of a fixed roll 15.1 and a roll 15.2 adjustable relatively to roll 15.1 at a distance A (cf. Fig. 5) in the shown embodiment, a defined drafting force is exerted on the roving 3. The drafting force is adjusted by the distance between the two rolls 15.1 and 15.2. The material to be processed located outside rolls 15.1 and 15.2 is termed sliver 4. Rolls 15.1 and 15.2 are slewably fitted on axes 16.1 and 16.2 (cf. Figure 5) and, if required, can also be driven. In the shown, embodiment axis 16.1 is rigidly fixed to a casing 17. Axis 16.2 and with it roll 15.2 is also fixed to casing 17 and can, in opposition to roll 15.1, be dislocated radially in its axial distance A (cf. Figure 5). For this purpose there is a manually or remotely controllable adjusting mechanism (not shown in detail) inside casing 17. Of course, in order to achieve drafting which is adapted to the characteristics of the material of sliver 4 to be processed into roving 3, technically equivalent solutions can be provided by means of embodiments with more rolls than the embodiment with the two rolls 16.1 and 16.2 shown here (cf. Fig. 7). The momentary pressing force of rolls 16.1 and 16.2 can be determined and analyzed by means of pressure sensors of e.g. piezoelectric nature which are also preferably located in casing 17. The energy supply and transmission of measuring and adjusting signals of drafting mechanism 2 and the adjusting mechanisms on the inside of casing 17 are carried out via a connecting cable 18. The here shown facility can also include measurement of parameters to obtain information on production related aspects like length of roving, production strips, weight of roving and others. Figure 5 shows sensor 1, drafting mechanism 2, roving 3 and sliver 4 viewed from behind. The back side of casing 17 of drafting mechanism 2 is removed (which is indicated by the hatching) such that axes 16.1 and 16.2 of rolls 15.1 and 15.2 can be seen. Distance A of axes 16.1 and 16.2 is variable such that the pressing force acting on roving 3 or sliver 4 can be adjusted. The CCM control unit 5 is for registration and transmission of the measured data and monitoring of sensor 1 and drafting mechanism 2. These elements form a basic unit and can be extended with additional sensors if required. One such module is advantageously used for the online monitoring of one roving process. Figure 6 shows a further embodiment in which a modular basic unit 6 consists of a CCM control unit 5 and eight sensors 1.1 to 1.8. The design of a module 6 basically depends on the concept of the CCM control unit 5 and thus can function in spite of the difference in appearance. Here the arrangement of sensors 1.1 to 1.8 is chosen such that the roving 3.1 to 3.8 is guided through the sensor plates 10.1 to 10.8 from top to bottom. The CCM control unit 5 is advantageously designed such that it can register the results of all eight sensors 1.1 to 1.8 sequentially at very short time intervals or in parallel. Figure 7 shows another preferred embodiment comprising a sensor 1, drafting mechanisms 2.1 to 2.4, a CCM control unit 5, a roving 3, a sliver 4, and connecting cables 12, 18, 19. The three drafting mechanisms 2.1, 2.2 and 2.3 are controlled by the CCM control unit 5 and are responsible for the adjustment of the thickness and the correction of long term faults of the sliver. They receive their response from the sensor 1 in functional connection with the CCM control unit 5. The drafting mechanism 2.4 is also controlled by the CCM sensor unit 5 and is located on the opposite side of the sensor 1 so that the sliver 4 passes first the drafting units 2.1 to 2.3 and the measuring filed 13 of sensor 1 and then passes the drafting unit 2.4. While the drafting units 2.1 to 2.3 are responsible for long term corrections, the drafting unit 2.4 is foreseen to correct short term and random faults. It is also controlled by sensor 1 in functional connection with CCM sensor unit 5. If desired the precision of this preferred arrangement can be enhanced to meet specific targets by adding more sensors 1 and/or drafting units 2. WE CLAIM : 1. A device for extracting defective roving (bobbin) out of a multitude of simultaneous roving processes, comprising : a module for periodically or continuously generating measured values of each of said simultaneous roving processes ; a module for dynamically calculating a reference value from at least one of said measured values ; a module for comparing each of said measured values with said reference value ; a module for sending and/or displaying a separation signal by which defective ravings are separated ; and, means such as sensors (1.1 to 1.8), at multiple production positions, for sensing relevant material parameters such as quality and volume of fiber material, and for analyzing the information, thus obtained, by comparing the results tested at various points in time within a single process, in order to determine parameters such as herein described. 2. The device as claimed in claim 1 comprising a module for sending and/or displaying information for localizing said defective ravings and/or information about the degree of deviation from said reference value. 3. The device as claimed in claim 1 comprising a module for calculating said reference value from a representative subensemble of said measuring values. 4. The device as claimed in claim 3 wherein the composition of said subensemble is changed periodically or non-periodically with time. axial distance A (cf. Figure 5). For this purpose there is a manually or remotely controllable adjusting mechanism (not shown in detail) inside casing 17. Of course, in order to achieve drafting which is adapted to the characteristics of the material of sliver 4 to be processed into roving 3, technically equivalent solutions can be provided by means of embodiments with more rolls than the embodiment with the two rolls 16.1 and 16.2 shown here (cf. Fig. 7). The momentary pressing force of rolls 16.1 and 16.2 can be determined and analyzed by means of pressure sensors of e.g. piezoelectric nature which are also preferably located in casing 17. The energy supply and transmission of measuring and adjusting signals of drafting mechanism 2 and the adjusting mechanisms on the inside of casing 17 are carried out via a connecting cable 18. The here shown facility can also include measurement of parameters to obtain information on production related aspects like length of roving, production stops, weight of roving and others. Figure 5 shows sensor 1, drafting mechanism 2, roving 3 and sliver 4 viewed from behind. The back side of casing 17 of drafting mechanism 2 is removed (which is indicated by the hatching) such that axes 16.1 and 16.2 of rolls 15.1 and 15.2 can be seen. Distance A of axes 16.1 and 16.2 is variable such that the pressing force acting on roving 3 or sliver 4 can be adjusted. The CCM control unit 5 is for registration and transmission of the measured data and monitoring of sensor 1 and drafting mechanism 2. These elements form a basic unit and can be extended with additional sensors if required. One such module is advantageously used for the online monitoring of one roving process. dynamically calculating a reference value from at least one of said measured values ; comparing each of said measured values with said reference value ; sending and/or displaying a separation signal by which defective rovings are separated ; sensing and analyzing the information thus obtained by comparing the results tested at various points in time within a single process ; and, obtaining defect-free roving (bobbin) out of defective roving , so extracted. 12. The method of claim 11 wherein said separation signal comprises information for localizing said defective rovings and/or information about the degree of deviation from said reference value. 13. The method of claim 11 wherein said reference is calculated from a representative subensemble of said measuring values. 14. The method of claim 13 wherein the composition of said subensemble changes periodically or non-periodically with time. 15. The method of claim 11 wherein preliminary reference values are calculated from at least two subgroups, each subgroup consisting of a selection of said measured values, said preliminary reference values are compared with each other, and the measured values forming a subgroup are excluded from calculating said reference value if the preliminary reference value from said subgroup deviates from another preliminary reference value by a defined deviation. 16. The method as claimed in claim 11 wherein defective ravings are eliminated manually or automatically after receiving said separation signal. 17. The method as claimed in claim 11 wherein said measured values are selected from the group consisting of thickness, especially hank ; distribution of thickness over length, especially unevenness, cut length, roving stretch, hank variation ; and/or periodic faults of said roving process. 18. The method as claimed in claim 11 wherein a statistical distribution is calculated from said measured values, and subsequently statistical characteristics of said distribution are evaluated, classified and, if desired, saved in a library for later decision finding. 19. The method as claimed in claim 11 wherein environmental influences are caused to be compensated by evaluating and comparing said measured values with said reference value. 20. The method as claimed in claim 11 comprising a periodical or continuous generation of measuring values within one roving process. 21. A device for carrying out the method as claimed in claim 11 comprising a sensor for measuring the fiber mass. 22. The device as claimed in claim 21 wherein said sensor is a capacitive sensor. 23. The device as claimed in claim 21 comprising a processing unit, which serves to control a drafting mechanism, and a servo unit standing in a functional connection with said processing unit. 24. A device for extracting defective roving (bobbin) out of a multitude of simultaneous roving processes, substantially as herein described, particularly with reference to and as illustrated in the accompanying drawings. 25. A method for extracting defective roving (bobbin) out of a multitude of simultaneous roving processes, substantially as herein described, particularly with reference to and as illustrated in the accompanying drawings. The invention disclosed makes it possible to monitor and analyze the most important fiber quality parameters such as thickness, distribution of thickness over the length, periodical faults and others in real time by means of registration of the parameters influencing the production process by means of sensors and leading them to a suitable analyzing unit. A device for extracting defective roving (bobbin) out of a multitude of simultaneous roving processes, comprises : a module for periodically or continuously generating measured values of each of said simultaneous roving processes ; a module for dynamically calculating a reference value from at least one of said measured values ; a module for comparing each of said measured values with said reference value ; a module for sending and/or displaying a separation signal by which defective rovings are separated ; and, means such as sensors (1.1 to 1.8), at multiple production positions, for sensing relevant material parameters such as quality and volume of fiber material, and for analyzing the information, thus obtained, by comparing the results tested at various points in time within a single process, in order to determine parameters such as herein described.

Documents:

00961-cal-1998-abstract.pdf

00961-cal-1998-assignment.pdf

00961-cal-1998-claims.pdf

00961-cal-1998-correspondence others.pdf

00961-cal-1998-description complete.pdf

00961-cal-1998-drawings.pdf

00961-cal-1998-form 1.pdf

00961-cal-1998-form 2.pdf

00961-cal-1998-form 3.pdf

00961-cal-1998-gpa.pdf

00961-cal-1998-letter patent.pdf

00961-cal-1998-reply f.e.r.pdf