Patent GB-1370767-A (GB)
Title: Fabric twist detecting and correcting apparatus
IPC: D06B23/08
Filed: 1973-03-27
Abstract: 1370767 Detecting and correcting fabric twist TOYO MACHINERY CO Ltd 27 March 1973 [31 March 1972 20 April 1972] 14716/73 Heading D1S [Also in Division G3] Apparatus for detecting and correcting the twist of a travelling fabric strip F, Fig. 1, comprises a twist detecting unit B and a twist correcting unit C disposed upstream of the unit B in the direction of travel of the fabric F, the unit B including a twist detecting element 3, Fig. 3, having a working surface 4 movable positively along the surface of the fabric F in sliding contact therewith and longitudinally thereof and switch means 6 for rotating a drive motor 18 for the unit C in a direction to correct the twist, the switch means 6 being actuatable in response to the detecting operation of the element 3, the unit C including rotary means 14, Fig. 7, driven by the motor 18 for rotating fabric embracing means 11, 12 in either direction. In one embodiment, Figs. 1, 3 and 7, a pulley A is located between the units B, C and the untwisted fabric is spread by a machine D. The element 3, Fig. 3, is a disc made of a metal sensitive to magnetism and which is keyed to the shaft 2 of a reversible motor 1 so as to rotate therewith but slide axially therealong. The working surface 4 may be provided by a brush, as shown, or by serrate projections. Metal sensors 5 are mounted on opposite sides of the disc 3 and send a signal in response to the axial movement of the disc 3 by the fabric twist to close one or two relay circuits 6 to rotate the motor 18, Fig. 7, in normal or reverse direction. The fabric F is guided by a plate 8 having a slot 7 into which the brush 4 projects and is pushed towards the plate 8 by a plate 10 acted on by a spring 9. In the unit C, the fabric embracing means comprises four pushers 11, Fig. 7, having plates 12 urged towards the fabric F by springs 13 and is accommodated in a cylindrical rotary member 14 rotatably slidingly supported in a cylindrical support 16. The motor 18 rotates the member 14 to correct the twist. In a modification of the unit B, Fig. 5, the sensors 5 are replaced by pneumatic sensors 23 each comprising an air inlet 21, an outlet 22, and a diaphragm 24 urged by a spring 25 towards the outlet 22. When the twsit of fabric shifts the disc 3 in one direction the disc closes the respective outlet 22 so that the diaphragm 24 moves against the spring 25 and pushes a rod 26 to close a microswitch 27 to operate a unit C. In another modification, Fig. 6, the disc 3 is provided with a projecting flange the movement of which axially of the shaft 2 is detected by photoelectric devices, comprising projectors 31, 33 and receivers 32, 34, which operate the unit C. In a further embodiment, Fig. 10, a second twist correcting unit C' is provided between the pulley (A) and the unit (B). The unit C' corrects the twist detected by the unit B and the unit C nullifies a twist produced by the unit C'. As shown, the units C, C' have cylindrical rotary members 46 driven by a single motor 41 through a belt 48 and bevel gears 47, 49. In a modification, Fig. 11, the fabric embracing members are carried in worm wheels 51 rotated by worms 52, 53 on a shaft 56 and which act in opposite directions, the shaft 56 being driven by a motor 55.