Method for monitoring/adjusting production in a knitting...

Textiles: knitting – Feeding – With yarn treatment

Reexamination Certificate

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Reexamination Certificate

active

06832496

ABSTRACT:

FIELD OF THE INVENTION
The invention relates to a method for monitoring/adjusting production in a knitting machine, and a monitoring/adjusting device therefor.
BACKGROUND OF THE INVENTION
In the knitting technology, electronic data processing is increasingly employed not only for machine control purposes but also for monitoring/adjusting the production. Furthermore, it is conventional to establish a masterpiece by calculating or producing on the basis of target yarn amounts and to use the masterpiece as a reference for the production of a machine or of an entire machine series. In this case comparisons are carried out with the masterpiece, e.g. with the help of the consumed yarn amounts and/or the developments of the yarn consumption. The yarn consumption is an important aspect for a knitting mill and the specialised personnel. In case of simple, plain knitted and straight tube fabrics and equipment of the circular knitting machine with positive feeding devices, the yarn tensions vary. However, the yarn amounts remain constant in relation to the machine speed such that it does not cause any problems with respect to monitoring and evaluating the yarn consumption. Furthermore, methods exist according to which the yarn amount is measured by means of a measuring roll running in the yarn path, and according to which the measured values are evaluated centrally, however, such methods require excessively high technical efforts and complicate the re-setting, adjustment and changing of the machine setting considerably.
In a device known from EP 0 452 800 A the respective yarn amount is determined and evaluated centrally with the help of measurements of the yarn speed by means of special sensors in the yarn path. The yarn amounts consumed in the masterpiece are used for comparisons with the knitted goods in order to detect and display erroneous uses, incorrect yarn speeds and incorrect machine operation cycles.
In the case of jacquard goods or so-called body stockings, however, non-positive feeding devices of different types operating with different yarn conveying principles are used for different yarn qualities, sometimes even of different producers, at one and the same knitting machine. In such cases, the monitoring and detection of the individual yarn amounts until now is impossible with reasonable control equipment and apparatus efforts. Basically, however, consecutive, sequential or final information of the yarn amounts of such specially equipped knitting machines would be important for the knitting mill owner and the specialised personnel in order to judge and optimise the efficiency of the production, to realise fluctuations of production parameters during the production early on, to save time and labour effort for the pre-setting, changes of the setting and adjustment, and to achieve an optimisation of the quality and continuous high quality with fewer defective goods.
According to a method known from DE 82 24 194 U the yarn amount is measured per revolution of the knitting machine. For this purpose a scanner is co-acting with a band commonly driving all feeding devices provided at the knitting machine. The method can only be used for positive feeding devices at the knitting machine, which positive feeding devices commonly are driven by a band. All feeding devices operate with equal feeding rates and with identical yarn conveying principles.
According to a method as known from EP 0 489 307 A, the entrance speed of each yarn into a knitting system is constantly maintained equal or proportional to an entrance speed which is predetermined by a self-learning cycle on the basis of a masterpiece. Control of the entrance speeds is carried out during the production run of the knitting machine. Furthermore, during the production run a driven actuator, e.g. a roller, pulls the yarn from a storage bobbin such that the yarn is fed during the production run with a constant yarn quantity. The actuator determines the entrance speed of the yarn. The self-learning cycle is carried out prior to the start of the production run of the knitting machine without using the actuators in order to find out respective decisive yarn quantities. The actuators correspond to positive feeding devices. The actuators are identical among each other and operate with equal yarn conveying principles. A sensing roller is provided as a sensor at each yarn between the actuator and the yarn guide into the knitting system of the knitting machine. The sensing roller measures the yarn quantity and informs a console unit or a microprocessor also provided for the drive control of the respective actuator. The roller sensing the yarn quantity is an undesirable additional mechanical load for the yarn and emits imprecise measuring results due to unavoidable slip.
Further prior art is contained in EP 0 752 631 A, EP 0 959 742 A, EP 0 600 268 A, DE 82 24 194 U, EP 0 420 836 A, EP 0 385 988 A, EP 0 489 307 A.
The setting procedure of a knitting machine prior to production or after a change of the settings is particularly time consuming and requires special knowledge, particularly when the knitting machine is equipped with non-positive feeding devices which may even originate from different producers, and even differentiate from each other in terms of the respective yarn conveying principles, because each feeding device including its peripheral, yarn influencing accessory assemblies has to be associated with the respective knitting system and has to be adjusted to an individual and optimum operation. In this case simply achievable information on the individual yarn amounts was of invaluable advantage since a yarn amount deviating from a target indicates for such a feeding device not only a fault condition or a trend, but even allows a direct conclusion to the kind of a fault which then could be corrected rapidly and at that point. Furthermore, in view of this aspect there is considerable demand for a method for an efficient monitoring adjustment of the production for knitting machines having non-positive feeding devices, and for a device allowing for a simpler pre-setting, changing of settings and the adjustment of a knitting machine or even of a knitting machine series.
It is an object of the invention to provide a method of the kind as disclosed above as well a device for carrying out the method which allow a simple and comfortable monitoring/adjustment of the production despite the fact of the existence of non-positive yarn feeding principles of feeding devices of different types which even operate according to different conveying principles.
By carrying out the method such that each individual yarn amount is continuously measured with the help of detected actual rotational signals of the feeding device, a sufficiently precise yarn amount information is achieved from the actual rotational signals under consideration of the storage body circumferential length and without the need to use separate sensors for these tasks. Actual rotational signals are used in any event which result from the operation of the feeding device. Even though several non-positive feeding devices are used at the knitting machine which feed yarn of different qualities and/or elasticity according to at least two different yarn conveying principles, and which even may originate from different producers, the actual rotational signals can be detected easily. According to the method, the individual yarn amounts are detected precisely and deliver information for the monitoring/adjustment of the production. One reason for different feeding device types is that the feeding devices have to cope with different yarn tensions and/or yarn speeds, with one type having better capabilities than another type. Within the frame of the method the individual yarn amounts are not measured primarily to gain the total yarn amount but to indicate with the help of the yarn amounts certain fault conditions in order to allow one to survey and optimise the production in a simple way. As a secondary product, the total yarn amounts can also then be detected with little additional effort. Th

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