US 4,924,406 AGranted

Optical slub catcher, particularly suitable for openend process

AssigneeNuovopignone Industrie Meccanichee Fonderia S.p.A.

InventorsGiorgio Bergamini, Tommaso Cipriani

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Abstract

An optical slub catcher, particularly suitable for open-end process weaving machines, comprises a special optical head for the measurement of yarn diameter, the analog signal of which is cleaned of the disturbances due to ambient light. This analog signal is furthermore normalized by an original compensating and normalizing unit, and is then digitized. The slub catcher of the present invention is also provided with the following: a detector unit for the detection of Moire defects, a detector unit for the detection of the % VC irregularities, and a unit for spectrogram processing. In addition, the slub catcher of the present invention compensates for dirt build-up, thermal drifts, and aging of the optical head which affect the performance of the slub catchers of the prior art.

Claims8

Dependent claims

An optical slub catcher for weaving unit of the open-end type comprising:

(a) optical head means for measurement of yarn diameter that supplies an analog signal proportional to said yarn diameter, said analog signal being used to control production of yarn and to determine yarn characteristics;
(b) compensation means coupled to said optical head means for amplifying, demodulating, and normalizing said analog signal;
(c) an analog-digital converter coupled to said compensation means for converting said analog signal into a digital value;
(d) modulation means coupled to said optical head means for supplying said optical head means with a pulsating current;
(e) timer and sequences generator means coupled to said modulation means for driving said modulation means;
(f) central processing means for analyzing data and controlling the operations of said slub catcher connected to said modulation means and said timer and sequences generator means;
(g) presetting means for presetting a reference average yarn diameter connected to said central processing means;
(h) subtractor node means for calculating the error of a measured yarn diameter with said reference average yarn diameter connected to said central processing means;
(i) count control means for synchronizing the parts of said slub catcher connected to said central processing means;
and
(j) calculation means for calculating a unitary diameter of the yarn connected to said central processing means.

8 more elements

Dependencies are inferred from the claim text.