Yarn tension sensor with improved calibration
AssigneeMemminger-IRO GmbH
InventorsHermann Schmodde, Eberhard Leins, Friedrich Weber
Life of this patent
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Abstract
A yarn feeder intended particularly for flatbed knitting machines and elastic yarns has a yarn tension sensor which is provided with a calibration device. This device lifts the yarn from a peg that is part of the yarn tension sensor, at times in which this can be done without impairing operation of the yarn feeder. Such times are preferably time slots when no yarn feeding is necessary. Once the yarn has been lifted from the peg, a zero point calibration is performed. Zero point drifting of the entire sensor system, including its measurement circuit, can be detected and compensated for.
Claims26
A yarn tension sensor (1) for detecting the tension of a moving yarn (7), comprising:
- a yarn feeler element (21), which is disposed in a yarn travel path and has a bearing face for the yarn (7),
- a measuring device (5), connected to the yarn feeler element (21), for detecting the force exerted by the yarn (7) on the yarn feeler element (21), and
- an actuator device (48), by means of which the yarn feeler element (21) and the yarn (41) are movable relative to one another between a calibration position and a measurement position in such a way that in the calibration position, the yarn does not rest on the yarn feeler element (21), and in the measurement position, the yarn does rest on the yarn feeler element (21).
A method for calibrating a yarn tension sensor comprising the steps of:
- detecting a signal that defines a state in which the yarn tension is allowed to deviate briefly from its set-point value,
- separating a yarn from the yarn tension sensor,
- detecting the signal output by the yarn tension sensor once the yarn has lifted, and
- placing the yarn on the yarn tension sensor again.
Dependencies are inferred from the claim text.