Verfahren zum Feststellen der Schussfadenlage von laufenden Gewebebahnen und zur Steuerung von Schussfaden-Richtapparaturen und Vorrichtung zur Durchfuehrung des Verfahrens

摘要

1,169,778. Measuring weft alignment photoelectrically. H. MAHLO. Dec. 1, 1967 [Dec. 2, 1966], No. 54822/67. Heading G1A. [Also in Division D1] Angular deviations of weft threads in a moving fabric are detected by scanning the fabric with a photo-electric scanner and rotating the scanner in response the scanner output signal to follow the angle of the weft. The scanner ZO for the web G comprises photo-cells F1, F2 with associated slits S1, S2. The amplitude of the A. C. outputs from F1 and F2 depends upon the angle made by the weft threads and the slits S1, S2. The outputs are rectified by diodes Dl, D2 and any difference operates a polarized relay Rel whose contact K completes the circuit of a motor M to rotate the scanner ZO until the weft threads bisect the angle between slits S1 and S2. The scanner position is indicated by a meter J energized through a potentiometer MP driven by the scanner. The photocells F1 and F2 may be replaced by a single photo-cell to which light is directed from the slits S1, S2 alternately by a tilting mirror, Fig. 2 (not shown). The cell output is directed to diodes Dl, D2 in synchronism with the mirror oscillations. The mirror may be replaced by an oscillating shutter if a larger photo-cell is used, Fig. 3 (not shown). A single slit and photo-cell oscillatable between the positions S1 and S2 may be used, Fig. 4 (not shown). An oscillating system comprising an electromagnet may be provided the photo-cell signal being switched between the diodes D1 and D2 by the contact of a relay energized by a contact made by the swinging photocell arm Fig. 12 (not shown). The current through meter J may provide a control voltage for weft straightening means preferably with the addition of a control voltage from the current through relay Rel to combat time delay, Fig. 7 (not shown). In another embodiment, Fig. 5, the slit S5 and photo-cell F5 are fixed in the scanner and the motor M is energized alternately in opposite senses through contacts l3 and r3 of a relay system P, N, L, R, which changes its state at a time related to the maximum output from the photocell F5. Consequently the mean position of the oscillating scanner follows the angle of the weft threads, and this mean position is determined by the capacitor C1 from the oscillating output of potentiometer P and displayed on meter J. In another embodiment, Figs. 8-11 (not shown) light reflected from the fabric from a fixed light source is received by a pair of photo-cells on the scanner head. Reference has been directed by the Comptroller to Specification 871, 325.