Title of Invention

METHOD FOR ADJUSTING WEFT YARN TENSION AND A LOOM

Abstract

ABSTRACT "Method for adjusting welt yarn tension and a loom” Method for adjusting the yam-tension conditions at least during the starting phase of an electronically controlled projectile loom or rapier loom (L) by inputting into a control unit a characteristic which is associated at least with the quality that is to be processed and using said characteristic for controlling the brake. Several expert results (K1 to K5) of at least a brake actuation characteristic (A1 to A5), which provided optimal tensioning conditions at least during pre-trials with different yam qualities, are determined during the pre-trials and are encoded differently for the different qualities. An expert result which matches the quality that is to be processed is selected for at least one brake actuation characteristic (A1 to A5) in a programmed electronic expert system (E) of the loom (L), and said brake actuation characteristic is adjusted and used at least during the loom start-up phase for controlling the brake.

Full Text

METHOD FOR ADJUSTING THE YARN TENSION AND PROJECTILE LOOM OR RAPIER LOOM The invention relates to a method according to the preamble of claim 1 and to a projectile loom or rapier loom according to the preamble of claim 9. In order to achieve an economic production in modern projectile looms or rapier looms it is important that set-up times are very short. The optimum operation of the loom depends in particular from the varying course of the weft yam tension during each insertion. Different yam qualities need different adjustments of the yarn tension. Until now the adjustments have been made by the personnel according to the principle of trial and error. In this case, the time duration and the steps necessary until a sufficiently good setting is achieved depends on the experience and the precise working of the personnel, but the producers of loom accessories and/or the loom producers themselves did not have any influence on the time duration and the number of steps. In particular, not only the controlled yarn brake and the tension meter define dominant friction bound locations in the yarn path which gain influence on the course of the yarn tension in particular in projectile looms and rapier looms, but a further not controlled yarn braking device (brush brake or flex brake of a individually selectable type) is provided at the yarn feeding device which yarn braking device also generates friction on the yarn. All these components act differently depending on the yam quality and the type of the braking device and need a cumbersome stepwise approach to an optimum brake control of the controlled yarn brake. As these problems have been long known, projectile looms and rapier looms have been developed which contain a feedback control including an electric tension meter for the controlled yam brake (EP 0 357 975 A and EP 0 634 509 A). This feedback control is the result of a co operation between loom producers and loom accessory producers. According to a method as known from EP 0 357 975 A, a yam tension target characteristic is input into the brake control for controlling the brake in particular during the start-up phase of the loom. The yam tension target characteristics are correlated with the weft yam quality. Then a suitable brake actuating characteristic is sought by an operator who tries to improve the result with the help of input additional parameters. In this case the number of the steps and the time duration needed until a satisfying set-up is achieved depends from the experience and the precise work of the operator only since the operator does not have access to any clear instructions on the brake actuating characteristic for the yarn quality which is to be processed and for the machinery. According to the method as known from EP 0 634 509 A, a course of the yarn tension is input as a guiding variable for an adaptive tuning of the brake control. The course is selected dependent on the yam quality. Then subsequent corrections of the respective point of time of the actuation of the brake and the braking intensity are made according to the principle of trial and error and as clear instructions do not exist for suitable brake actuating characteristics. This is cumbersome and time consuming. The result only depends on the experience and precise work of the operator on which neither loom producer nor the loom accessory producer can gain influence even though both would know the best how an optimum adjustment of the yarn tension could be carried out most rapidly. It is an object of the invention to provide a method of the kind as mentioned above and a projectile loom or rapier loom allowing that a rapid and optimal adjustment of the yarn tension for the production operation of the loom is achieved in an operator-friendly way. This object is achieved by the features of claim 1 and of claim 9. By means of the expert result in the form of at least one brake control characteristic as determined by pre-trails and resulting during the pre-trials in optimal conditions of the yam tension, the operator has an operator friendly tool at hand for the set-up of the projectile loom or rapier loom for which he is in charge. With the expert result the operator has the possibility to immediately achieve a safe basic set-up for the start-up phase of the loom, e.g. after the set-up of the loom had to be changed. With the help of the safe basic adjustment, in most cases the respective loom can be brought to a safe operation. Only by inputting the suitable expert result, a relatively high level of reliability will be reached without the need for the operator to carry out a cumbersome trail and error process to reach an even worse result. Expediently, the expert results for the brake actuating characteristics are determined during the pre-trials and in correlation with the yam qualities. They are retrievably available in the expert system. Then the operator will be enabled if necessary, at all, starting from the already fairly good basic adjustment at least constituted by the set brake actuating characteristics to then carry out rapidly and without problems fine tunings towards an even more optimal condition of the yam tension in this loom by inputting further clear parameters. Clear has the meaning that these parameters may be easily derived by the operator himself from yam specific parameters and/or loom specific prerequisites or loom accessory equipment specific prerequisites, respectively. These factual parameters as such will not only be based on the experience or guesses of the operator. Since the expert results are well defined coded for different yarn qualities, the operator may, as soon as he has obtained information on the yam quality which is to be processed, without problems input the correct expert result into the expert system with the help of the code. The expert system then automatically will adjust the brake actuating characteristic which already lead to optimal yarn tension conditions for the same or an equal yarn quality in the pre-trails. By doing this, the operator is able to rapidly bring the loom to operation without cumbersome attempts to stepwise find a suitable set-up. For this reason, the set-up can even be made rapidly by relatively unskilled personnel. The projectile loom or the rapier loom is advantageously completed by the intelligent and programmed expert system which allows a rapid correct adjustment of the conditions of the yarn tension only by means of a simple predetermined code and in a comfortable fashion for the operator. In this way the adjustment experiences of the producers will be transplanted into the loom independent of the operator's level of skill. As according to a particular expedient embodiment of the method, both a brake actuating characteristic and a yarn tension target characteristic for the yam quality which is to be processed are set only by inputting the correct code, and in particular, characteristics which were determined as optimal in advance by pre-trials carried out by experts under equal conditions, such that cumbersome trials achieving good conditions for the start-up phase after a machine changeover are avoided. The operator is relieved of this procedure for which result the quality depends on experience and a very high degree of precision. If needed, however, a fine tuning then can be carried out starting from a high level of reliability and with the help of well-defined parameter inputs which automatically result from the yam quality and/or the machine equipment and which do not need special skill or high attention from the operator. Because the expert results are based on high standard experiences of the loom producers and loom accessory producers, the set-up can be carried out rapidly and straightforwardly at least for the start-up phase. The method is extremely convenient for the operator as the provided programmed electronic expert system only needs to input the correct code which code for the yarn quality to be processed can be understood immediately by the operator such that the operator immediately knows how to correctly employ this code. By inputting the correct code, the expert system already is brought to a high level of reliability of the set-up. The personnel then may easier achieve more optimal yarn tension conditions rapidly and conveniently when starting from this high level of reliability. Expediently, the input expert result is implemented directly, i.e. the start-up phase is started with the set-up made by the code as input Alternatively, however, it is possible that the expert result will be implemented after being modified by the expert system. The modification is carried out by considering at least one well-defined parameter which is specific for this loom and/or the yarn quality. In the case that e.g. a specific aggressive and/or mild yam braking device is provided at the yam feeding device, what can be seen by the operator without significant skill, it is possible to e.g. input the parameter "aggressive bristle brake" to already immediately modify the basic adjustment of the expert result and to implement the modified adjustment, e.g. by somewhat alleviating the brake actuating characteristic in view of the aggressive braking device in the yarn feeding device. Expediently, each expert result is a well-defined code for the yarn quality in the form of a yarn-type group coding, or a yarn count coding and a yarn material coding, or in the form of other yam specific parameter codes. These codes can be easily associated to the yarn material which is to be processed by the operator without lengthy considerations such that the operator easily is enabled to input the correct code. For this reason, e.g. the expert system may be programmed such that it automatically retrieves and implements the suitable expert result after only the yam count and the yarn material are input. Although an already good set-up will be achieved with the input expert results, it cannot be totally excluded that an individual characteristic of the weft yam material and/or of the friction generating components in the yam path may cause slight deviations from the optimum yam tension conditions as achieved during the carried out pre-trials. For this reason it is expedient to program the expert system such that at least during the start-up phase comparisons are made with measured actual yam tension values in order to derive correction values for an optimization. Such a derived correction value then either is displayed to the operator such that the personnel conveniently can carry out the corresponding fine tuning, or the correction value is immediately processed internally and automatically in a self-learning system (closed regulation loop). Such a fine adjustment can be carried out rapidly and easily because relatively suitable basic adjustments of the brake actuating characteristic and of the yarn tension target characteristic already exist which fit relatively well to the weft yarn quality which is to be processed such that already beginning at a relatively high level of the reliability of the adjustment as a starting point such corrections will be very efficient. For observation by and for informing the personnel, it is expedient to display the brake actuating characteristic and, in some cases, the yam tension target characteristic for the operator as resulting from the input code, e.g. on a display and, preferably, to propose to the operator modifications by inputting well-defined parameter values. Particularly expedient for this purpose, a menu is configured which offers the operator pre-formulated questions to well-defined parameters which questions will then be answered by the operator by considering the equipment of the loom and the yarn material. By doing this the operator is able to supply additional information which then is evaluated and processed by the expert system for characteristic-modification purposes. Expediently, furthermore, the respective expert result is formed of several brake actuating levels and/or yarn tension target values which are distributed within the angle range of the insertion or over the time duration of the insertion, or is formed of curves or tables representing the brake actuating characteristic or the yarn tension target value characteristic.This might be useful as phases occur within an insertion process which are differently critical in view of the yarn tension. Expediently, both an associated brake actuating characteristic and a yarn tension target characteristic will be jointly adjusted in the projectile loom or the rapier loom by using the input expert result. In this case it is particularly easy to carry out fine tunings with the help of occurring deviations between the actual yam tension characteristic as achieved with the operation of the controlled yam brake and the yarn tension target characteristic. The expert system also might be programmed to generate a correction value for the brake actuating characteristic and/or the yam tension target characteristic. The correction value is determined internally by a comparison of measured yarn tension values and the yam tension target characteristic. To inform the operator what then should be input the correction value should be displayed. Alternatively or additively the correction value may be processed automatically while controlling the brake, preferably, by the expert system. Furthermore, the expert system should be programmed such that it displays the set characteristics, e.g. in a display for the operator, and such that they preferably can be surveyed and/or modified by the operator by means of well-defined input parameter, preferably by using a configured operator enquiring menu. The operator then does not need to use his own experience because he will be guided by the expert system and will be asked to input well-defined parameters which will then be processed by the expert system correspondingly. Finally, the expert system also should be programmed for retrieving at least the loom speed and/or the weaving width in order to consider this information when controlling the brake. This is because variations of the loom speed,e.g. may have a significant influence on the yarn tension conditions during operation and during the start-up phase. As e.g. the used expert results are based on pre-trials also with different loom speeds, the expert system then is able to automatically adapt to the loom speed with the help of the loom speed information, or that the expert system then asks the operator to make corresponding fine adjustments. In the simplest case, the operator chooses the yarn type on the control panel of the loom. Then the expert system sets the suitable braking characteristic, e.g. for the start-up phase, and in some cases, the suitable yam tension target characteristic ready for their implementation. The information on the loom speed, the weaving width, the machine position (i.e. the angle range of the respective rapier positions or projectile positions within an insertion process, for which positions a certain yam tension is of particular importance) will then be considered by the expert system in combination with the chosen yarn type. A yam type or yam type group can be input, e.g. by the operator after considering specific yarn parameters. Additionally or alternatively, the operator may input other specific yam parameters such as the yarn material, the thickness, the elasticity, or the yam impregnation. In some cases, even a so-called yarn quality sensor may be provided in the loom which automatically detects several or all relevant yam specific yam parameters and transmits the parameters to the expert system. Then the expert system may offer different alternative information for the operator which are easily understood, e.g. in the control panel of the loom and such that the characteristics which were first set automatically then may easily be modified. Modifications of the set characteristics as initiated by the operator may be displayed and recorded as well. From the yam type and from input machine parameters, in some cases, the final brake adjustment result also can be displayed. Furthermore, additional inputs are possible in order to e.g. find out the friction conditions in advance and to consider them during the adjustment by measuring the yarn tension for a certain brake actuation of the controlled yam brake, e.g. during the non-braking state, and to then input the result into the expert system as an additional information. In this case the yarn even may be pulled through, e.g. by hand, or during a "stow pick" of the loom, respectively. Such a yarn tension test either may be called-up automatically as a program routine by the expert system via the loom control device, or may be initiated upon demand by an operator command. Such a tension test may be carried out prior to the start-up phase or after a failed start-up in order to improve the adjustment. Additional inputs belonging to the tension characteristic, e.g. may be made by the operator with an easy-to-understand numerical code or by using a code which represents parameters of other elements which may influence the tension, e.g. a code for the type of the feeding device, for the type and the strength or gentleness of the braking device at the feeding device. In the last mentioned case, different power values may be set, e.g. by inputting "low, medium, high, or the like" which will then be considered by the expert system accordingly. An embodiment of the invention will be explained with the help of the drawings. In the drawings is: Figure 1 Schematically a rapier loom, and Figure 2 Expert results which are assigned to different yam qualities, prepared for adjusting the weft yarn tension in the rapier loom, e.g. of Figure 1. The method according to the invention will be explained for a rapier loom L (Figure 1) even though the method can also be applied at a projectile loom (not shown). In the rapier loom L, a bringer gripper 4 takes the free tip of the weft yam Y which is offered by a yam selector 3 out of a yam channel (several yam channels may exist). The bringer gripper 4 accelerates the weft yam Y from standstill and transports the free yam tip to the mid of a weaving shed 2 where a taker gripper 5 is positioned. The yarn tip is transferred to the taker gripper 5 which pulls the weft yam to the opposite end of the weaving shed 2. In an not shown projectile loom, the weft yam presented by the yarn selector will be drawn by a shot-in projectile in one run through the weaving shed. In the rapier loom L, e.g. the following phases of each insertion process are critical in view of the yam tension: the take-up phase of the bringer gripper 4 at the beginning, the transfer phase from the bringer gripper 4 to the taker gripper 5, and the very final phase of the movement of the taker gripper. In a not shown projectile loom, the following phases, e.g. are critical in view of the yam tension: the starting phase and when the weft yam is gripped by the projectile, the first acceleration phase of the projectile, the end phase of the projectile movement, and the actual end of the insertion process. During such critical phases, predetermined values of the yarn tension should not be exceeded or the yarn tension should not fall below in order to achieve an optimum operation of the loom. For this reason, an electronically controlled yam brake B is installed in the yarn path. The controlled yarn brake B allows to vary the braking force which is imparted on the weft yarn Y during an insertion process. The rapier loom L shown in Figure 1 includes a weaving shed 2, a yarn selector 3 (in particular in the case of several yarn channels), a bringer gripper 4 and a taker gripper 5. The operation of the rapier loom is controlled by an electronic control C1 having an inputting section 11 and an indicating section 12f e.g. a display. The respective yarn channel contains a yam feeding device F which withdraws a weft yam Y of a certain yarn quality from a storage bobbin 1, intermediately stores the weft yam on a storage body 6, and allows the weft yam to be intermittently withdrawn upon demand through a braking device 8 which belongs to the yam feeding device F and, in some cases, through a stationary withdrawal eyelet 7. The yam feeding device F has its own electronic control C2 which, in some cases (not shown), is interlinked with the loom control C1. Downstream of the yarn feeding device F are provided along the yarn path the electronically controlled brake B comprising an actuator 9, e.g. a lamella brake similar to that disclosed in WO 03/033385 A, and further downstream of the controlled yam brake B in this case an electronic tension meter T for measuring the actual weft yam tension (measured value b). The tension meter T could even be dispensed with. The controlled yam brake B is controlled by an electronic control C which supplies a current of a certain value or a voltage of a certain level to the actuator 9 in order to adjust the yarn brake between a not braking position and different positions generating different braking effects. The tension meter T if provided, is connected to the control C3 (feedback regulating loop). The control C3 may be connected to the loom control C1, e.g. in order to obtain information there from on the operating speed of the loom and/or the weaving width, or of the respective position of the taker gripper and the bringer gripper 4, 5. According to the invention, furthermore, an electronically programmed expert system E is provided which in Figure 1 is a part of the control C3 of the controlled yam brake B, or which may be connected to the control C3. Alternatively, the expert system E also could be connected to the loom control C1 or could be integrated into the loom control C1. The expert system E has an inputting section 10 (and in some cases an indicating section) where, e.g. codes Y1-Y5 which, e.g. are associated to different yarn qualities which are to be processed, may be put in and, in some cases, even further parameters assigned to the weft yam and/or to the machine equipment. The expert system E converts the respective input code Y1-Y5 at least into a certain brake actuating characteristic (values of the electric current or the voltage) and, in some cases, also into at least one yarn tension target characteristic. The input information is either processed in the expert system E or in the control C3 in order to actuate the yarn brake B at the respective correct point in time and with the correct braking force. In some cases, already now, the values b measured by the tension meter T are compared with the yarn tension target characteristic. Figure 2 explains the codes Y1-Y5 for the expert system E in Figure 1, out of which the expert system E reads a brake actuating characteristic A1-A5 and, if desired, additionally a yam tension target characteristic B1-B5. Then the expert system E makes, e.g. via the control C3, a corresponding adjustment. Characteristics as stored for the codes Y1-Y5 may be in the shown example millivolt values (and for the yam tension target characteristic, e.g. force values in cN) and are determined in advance by trials carried out for the same or for equal conditions. These trials have been carried out in comparable looms with most different yarn qualities and most different equipment and represent expert results K1-K5 for optimal adjustments as suitable for the different yarn qualities. In order to adjust the yam tension conditions, at least for the start-up phase of the rapier loom L of Figure 1, the following is done: The loom speed and/or the adjusted weaving width are already present in the control C3. Now and at the expert system E the suitable code Y1-Y5 for the yam quality which is to be processed is input by the operator at the input section 10. The codes Y1-Y5, e.g. are assigned to different yam qualities such that the operator immediately will know which code has to be taken for the yam quality in question. Alternatively, it is possible, e.g. by means of the input section of the loom or the input section of the expert system E, to solely input at least the yam number or yarn count and the yam material YCT + Mat. Then the expert system E itself will select the suitable code Y1-Y5. The expert result K1-K5 which belongs to the respective code Y1-Y5 can only be a brake actuating characteristic A1-A5 (in Fig. 2 indicated by dotted ends of the respective blocks), or expediently, even a combination of a respective brake actuating characteristic A1-A5 and a yam tension target characteristic B1-B5 which is assigned to the respective brake actuating characteristic A1-A5. The brake actuating characteristic may be defined by values of the electric voltage, e.g. in millivolts, and by angle values or time values within an insertion process. The respective yarn tension target characteristic B1-B5 may be defined by force values (in cN) and angle values or time values within an insertion process, expediently assigned to certain phases within the insertion process which are differently critical in view of the yarn tension, or in the form of a curve defining the respective characteristic and which will then be processed by the expert system E, respectively. A further alternative may be that the operator does not have to look for the code Y1-Y5 which is to be input, but only has to input e.g. the yam count number and the yarn material (YCT+Mat), before the expert system E assigns the correct code Y1-Y5 to this input information and carries out corresponding adjustments at least for the startup phase. A further possibility is to use a yarn quality sensor which scans the actual weft yam and delivers corresponding information to the expert system E or indicates versus the operator what to put in. A further possibility is to input information into the expert system on the type or properties of the braking device 8 of the yam feeding device F and/or of the type of the yarn feeding device. For this case, the expert system is programmed such that it also evaluates this information, as it does with the adjusted loom speed and/or the adjusted weaving width. Then the rapier loom L is set in operation and one insertion process or a series of insertion processes is/are carried out. The adjustments made by the expert system A may be displayed for the operator either in the input section 10 or in the input section 11 of the loom control. The operator then has an additional possibility of modifying the adjustments by inputting further parameters. The expert system E or the control C3, respectively, expediently is programmed such that it carries out comparisons between the measured actual yarn tension values b and the adjusted yam tension target characteristic (feedback control), and finally derives a correction value W in case of a significant detected deviation. The correction value W expediently is displayed to the operator such that the operator then may carry out corresponding fine tunings. In another case, the correction value W may be displayed, but at the same time may be processed in a closed regulating loop (e.g. in the control C3) e.g. to vary the brake actuating characteristic and to seek for a close coincidence between the actual measured yarn tension characteristic and the set yam tension target characteristic. From then on the rapier weaving can be operated normally in order to weave fabric. The control C3 is designed to adaptively control the brake, i.e. allows to carry out further fine adjustments, e.g. continuously, even during the normal operation, in case that a tendency to a change of the desired yam tension conditions should occur. Then further on the expert system E may be maintained out of function. Only by the brake actuating characteristic A1-A5 and without the yarn tension target characteristics B1-B5 among the expert results K1-K5 as set by the code Y1-Y5, which expert results stem from a plurality of pre-trials and had led then to optimal conditions of the yarn tension for the respective yarn quality, there already exists a basic adjustment for the yarn brake B, by which the rapier weaving machine can be set into operation without problems and with the largest likelihood. By this basic adjustment already a high level of reliability will be defined. This high level is a good starting point from which the operator or the expert system itself rapidly and in a straightforward way may carry out fine adjustments or re-settings which might become necessary. However, it is better to form the expert results K1-K5 respectively as a combination of a brake actuating characteristic and of a yam tension target value characteristic, because then comparisons with measured actual tension values can be carried out more conveniently and because correcting measures can be initiated operator friendly. CLAIMS 1. Method for adjusting weft yarn tension conditions at least during the start-up phase of the operation of an electronically controlled projectile loom or rapier loom (L) being equipped within at least one weft yarn channel with a yam feeding device (F) having a braking device (8) and an electronically controlled yam brake (B), by inputting and processing a characteristic during the brake control of the controlled yam brake (B) which characteristic is assigned to the yam quality as processed, characterized in that at least one brake control characteristic (A1-A5, B1-B5) is determined by pre-trials as an expert result (K1-K5) which brake control characteristic lead to a largely optimal condition of the yam tension during the pre- trials, and that the expert result is input either automatically or by an operator into a programmed electronic expert system (E) of the loom (L) and is implemented directly or indirectly for respectively actuating the controlled weft yarn brake (B) at least during the start-up phase of the loom (L). 2. Method according to claim 1, characterized in that a plurality of expert results (K1- K5) of at least brake actuating characteristics (A1-A5) are determined during the pre-trials for different yarn qualities which expert results had led, at least during the pre-trials, to optimal conditions of the weft yarn tension, and that one expert result (K1-K5) at least including one brake actuating characteristic (A1-A5) is selected which suits to the yarn quality as being processed, preferably is selected by means of a code, and that the selected expert result is input into and is implemented in the expert system (E) of the loom (L). 3. Method according to claim 2, characterized in that each expert result (K1-K5) is formed as a combination of a brake actuating characteristic (A1-A5) and of one yam tension target characteristic (B1-B5) which are to be adjusted and implemented, and that the combination is input into the expert system, while at the same time for achieving a feedback brake control a tension meter (T) is supplying measured values (b) of the actual yarn tension. 4. Method according to claim 1, characterized in that the expert result (K1-K5) is used by the expert system (E) after being modified by at least one clear parameter which is specific to the loom type and/or the yam quality. 5. Method according to claim 2 characterized in that each expert result (K1-K5) is coded for the yam quality in the form of a yam type group code or a yam count code and yam material code or in the form of other yam specific clear parameter codes. 6. Method according to claim 3 characterized in that at least during the start-up phase comparisons are carried out between the yam tension target characteristic (B1-B5) as assigned to the chosen brake actuating characteristic (A1-A5) and measured actual yam tension values (b), that correction values (W) for correcting the brake actuating characteristic (A1-A5) and/or the yam tension characteristic (B1-B5) are derived for optimization purposes by the expert system (E), and that the correction values (W) either are displayed to the operator or are automatically processed internally. 7. Method according to claim 4 characterized in that the adjusted weft yarn brake actuating characteristic and the, in some cases, adjusted yarn tension target characteristic is displayed to the operator, preferably in order to allow modifications through the operator by inputting parameters which are specific for the loom type and/or the yarn quality. 8. Method according to claim 2 or claim 3 characterized in that the respective expert result (K1-K5) is formed out of several different curves which represent brake actuation levels and/or yarn tension target values or even the brake actuating characteristic and/or the yarn tension target characteristic during an insertion process, the curves being taken as distributed within an angle range or a time range of an insertion process. 9. Projectile loom or rapier loom (L) comprising at least one weft yarn channel including at least one yam feeding device (F) having a braking device (8), an electronically controlled weft yam brake (B), and an electronic control system (C1, C2, C3) having control sections for the loom, for the feeding device and for the controlled yam brake, the control system as well comprising an input section (10, 11) for inputting at feast characteristics which are related to the yam quality, characterized in that at feast one of the control sections (C3) comprises an electronic and programmed expert system (E) into which an expert result (K1-K5) is stored for the brake control of the controlled weft yam brake (B) which expert result is predetermined by pre-trials for the yam quality which is to be processed, and that by the expert system (E) and with the help of the input expert result a brake control characteristic (A1-A5) is used in the loom which brake control characteristic lead to optimal yam tension conditions during the pre-trials. 10. Projectile loom or rapier loom (L) according to claim 9, characterized in that a brake actuating characteristic and a yarn tension target characteristic assigned to the brake actuating characteristic are set-up jointly by the input expert result (K1- K5), and that the tension meter (T) is provided for measuring the actual yarn tension and is connected to the expert system (E) to supply measured actual weft yam tension values (b). 11. Projectile loom or rapier loom (L) according to claim 10 characterized in that the expert system (E) is programmed for generating at least one correction value (W) for the brake actuating characteristic and/or for the yam tension target characteristic, which correction value (W) is derived from a comparison between measured actual yarn tension values (b) and the yarn tension target characteristic (B1-B5) as input, and that a generated correction value (W) is displayed to initiate inputs by the operator and/or is automatically processed during the brake control, preferably by the expert system (E). 12. Projectile loom or rapier loom (L) according to claim 9 characterized in that the expert system (E) is programmed for displaying the adjusted brake actuating characteristic and/or the yam tension target characteristic to the operator, preferably in order to allow monitoring and/or modifying by the operator who inputs clear parameters which are specific for the loom type and/or the yarn quality, preferably by programming for the configuration of an operator inquiry menu. 13. Projectile loom or rapier loom (L) according to claim 9, characterized in that the expert system (E) is programmed for retrieving at least the loom speed and/or the weaving width for an internal consideration during the brake control.

Documents:

1360-chenp-2006 complete specification as granted.pdf

1360-chenp-2006 abstract.pdf

1360-CHENP-2006 CLAIMS GRANTED.pdf

1360-CHENP-2006 CORRESPONDENCE OTHERS.pdf

1360-CHENP-2006 CORRESPONDENCE PO.pdf

1360-CHENP-2006 FORM 18.pdf

1360-CHENP-2006 FORM 3.pdf

1360-CHENP-2006 POWER OF ATTORNEY.pdf

1360-chenp-2006-abstract.pdf

1360-chenp-2006-claims.pdf

1360-chenp-2006-correspondnece-others.pdf

1360-chenp-2006-description(complete).pdf

1360-chenp-2006-drawings.pdf

1360-chenp-2006-form 1.pdf

1360-chenp-2006-form 3.pdf

1360-chenp-2006-form 5.pdf

1360-chenp-2006-pct.pdf