GB1358868A - Treatment of sheet material - Google Patents

Abstract

1358868 Guiding webs MOUNT HOPE MACHINERY Ltd 14 June 1971 27736/71 Heading B8R [Also in Division D1] Apparatus for straightening and aligning the thread formations of woven or knitted web material includes a series of rollers comprising, in order of the sequence of their engagement with a web 30: rollers 1, 2 and 3 of which 1 and 3 are braked; driven rollers 4, 5 mounted on respective curved axles 60, 62 which can be rotated to correct bow distortion of the web 30; a guide roller 6; a skew-correcting roller 7 carried on a pivotally mounted frame 124; and further rollers 8 to 11. Automatic positioning of the frame 124 and of the axles 60, 62 to straighten and align the web threads is effected by a control circuit responsive to signals derived from detectors 184 which sense skew and bow distortions in the web path between rollers 8 and 9. Further, the rollers 4, 5 and 10 are driven at different speeds so that different degrees of tension are applied in each zone defined between these rollers, these degrees of tension being so selected that the minimum tension consistent with the optimum performance of each of the operations of feeding, bow correction, skew correction and detection is applied in each of the corresponding zones. A suitable circuit for effecting the required speed control is described with reference to Fig. 6 (not shown). A modified construction in which the straightening operations are carried out in the reverse order to that of the apparatus of Fig. 1 is described with reference to Fig. 6 (not shown).