Method and system for the detection of faults in a length of textile
AssigneeMemminger-IRO GmbH
InventorsKarl-Heinz Muhlberg, Friedrich Weber
Life of this patent
Estimating the term…
Abstract
In a method and system for the detection of faults in a length of textile fabric, the length of fabric is continuously scanned by an electro-optical sensor head. Light detectors located in a strip-form sensing zone of the sensor head are assembled in groups and emit group-specific fault signals. These fault signals are analyzed multi-dimensionally for the identification of spot faults and/or long faults, the criteria for analysis being the signal amplitude, the signal length, the recurrence of the signals and their periodic repeat at each revolution of the machine. Display, control counter devices and the like are energized as a function of the result of the analysis.
Claims20
A method for the detection of faults in a length of textile fabric, especially in a tubular knitted fabric produced on a circular knitting machine or circular warp knitting machine, comprising
- electro-optically scanning, in strip form, a length of fabric in at least one zone, said zone being in strip form, by a sensing means;
- deriving electrical sensing signals characterizing the condition of the length of fabric at a number of sensing points lying within said strip form zone;
- maintaining a predetermined speed between the length of fabric and the sensing means in the direction transverse to the strip form zone during sensing, whereby the zones being scanned in the length of fabric are scanned a number of times;
- said method comprising further, in accordance with the invention,
- analyzing the signals in such a way that a distinction is made between different forms or different sizes of types of faults, and providing separate output signals in which the type of fault is separately identified,
- said analyzing step including
- collecting the sensing signals characterizing the individual sensing points into at least two group-specific fault signals;
- processing and analyzing the fault signals separately by amplitude, term or duration of signals, and determining non-repeating or repeating occurrence of fault signals of the separate groups;
- measuring and establishing by this analysis and by the fault analysis an identification of the type of signal wherein
- a) a spot type fault is identified if
- (i) in the case of at least one fault signal varying in amplitude from a prescribed first amplitude threshold value,
- (ii) the signal term exceeds a predetermined first time threshold value by at least a prescribed first period of time, and
- (iii) without a number of fault signals occurring together within a measuring period;
- b) a long type fault if
- (i) in at least two fault signals varying in amplitude from a prescribed second amplitude threshold value,
- (ii) the signal term exceeds a predetermined second time threshold value by at least a period of time which is shorter than said first time period, and
- (iii) at least two fault signals occur together within a measuring period;
- and
- c) unless the signals had all the characteristics of (a) above or all of the characteristics of (b) above are sensed, identifying the signals as not representing a fault;
- and
- providing separate output signals controlling an output means in which the types of faults are separately identified with respect to (a) or (b).
A system for the detection of faults in a length of textile fabric, especially in a tubular knitted fabric produced on a circular or circular warp knitting machine, and for distinguishing between spot type faults or holes and long type faults or runs, said system comprising
- electro-optical scanning means arranged in strip form to scan a length of fabric in at least one zone, wherein said zone is in strip form, and deriving electrical sensing signals characterizing the condition of the length of fabric from a number of sensing points within said strip form zones as scanned by said electro-optical scanning means;
- said fabric and said scanning means being relatively movable with respect to each other at an essentially uniform, predetermined rate, between the length of fabric and the sensing means in a direction transverse to the strip form zone during sensing, whereby the zones being scanned in the length of fabric are scanned a plurality of times;
- and
- a control, evaluation and analyzing unit analyzing the signals from said scanning means, and separating said signals into two group-specific fault signals, in which the individual signals are analyzed separately by amplitude, duration of signals, and repeating or non-repeating occurrence of fault signals of the separate groups,
- said control, evaluation and analyzing unit providing separate output signals controlling output means in which the faults are separately identified as
- a) a spot type fault is identified if
- (i) in the case of at least one fault signal varying in amplitude from a prescribed first amplitude threshold value,
- (ii) the signal term exceeds a predetermined first time threshold value by at least a prescribed first period of time, and
- (iii) without a number of fault signals occurring together within a measuring period;
- b) a long type fault if
- (i) in at least two fault signals varying in amplitude from a prescribed second amplitude threshold value,
- (ii) the signal term exceeds a predetermined second time threshold value by at least a period of time which is shorter than said first time period, and
- (iii) at least two fault signals occur together within a measuring period;
- and
- c) unless the signals had all the characteristics of (a) above or all of the characteristics of (b) above are sensed, identifying the signals as not representing a fault;
- and
- providing separate output signals controlling an output means in which the types of faults are separately identified with respect to (a) or (b).
Dependencies are inferred from the claim text.