GB979346A - Textile drafting - Google Patents

Abstract

979, 346. Levelling fibres. DEUTSCHER SPINNEREIMASCHINENBRAU INGOLSTADT NIEDERLASSUNG DER SCHUBERT & SALZER MASCHINENFABRIK A.G. July 13, 1961 [Jan. 14, 1961], No. 25369/61. Headings DID and D1N. [Also in Division G3] In a device for controlling the thickness of a bundle of fibres being drafted wherein the speed of one of the fibre forwarding means is controlled by the thickness of the sliver, a feed back loop responsive to the speed of said fibre forwarding means is connected with the means controlling the speed of the fibre forwarding means. In Fig. 1 the thickness of a band of fibres 1 to be drafted by pairs of rollers 2 and 3 is measured by rollers 11, 12 and a memory wheel 19 is set up according- ly. The positions of the steel pins of the memory wheel are then read by a choke 18 and the signals thus produced pass into an electronic circuit. Depending upon the magnitude of the signal one of a pair of electromagnets 28, 29 in the circuit is consequently energized and a belt 7 which forms the controlling element of a stepless gear in the drive path to the rollers 2, is moved via a pivoted lever and armature arrangement so that the draft applied to the fibrous band 1 is altered in a thickness regulating way. To compensate for faults in the gearing 6, 7, 8 (e.g. slipping of the belt 7) a generator 10 is driven in accordance with the speed of the rollers 2 as part of a negative feed back loop which feeds signals into the speed control circuit to oppose the signal originating at the choke 18. To override the control during starting up an electrically operated brake 33 is provided to lock the armature and a cut-out switch 34 is provided in the control circuit. In an alternative embodiment the arrangement of electromagnets 28, 29 and armature 30 is replaced by a reversible slave electric motor having two field windings which may be energized in the same way as electromagnets 28, 29, the slave motor controlling the belt shifting lever through a worm and toothed segment arrangement. Other types of electric motors or hydraulic or pneumatic motors may alternatively be used. In a further form the device is used to regulate the thickness of a web being drafted as it comes from a textile card. Since, in this case, the measuring rollers are placed between drafting elements no memory wheel is required and the movements of the lever carrying the movable measuring roller are converted into electrical signals by a core, mounted on the lever, moving in a choke.