Patent GB-1216223-A (GB)
Title: Method and device for regulating the thickness of slivers
IPC: D01H5/42
Filed: 1968-05-09
Abstract: 1,216,223. Automatic thickness control. ZINSER-TEXTILMASCHINEN G.m.b.H. May 9, 1968. [May 13, 1967], No.22131/68. Headings G3R. In a control system for regulating the thickness of slivers subjected to drafting wherein the speed of one of the several pairs of rollers is varied in accordance with an electrical control signal indicative of the deviation of the measured thickness from a desired value, therein provided a tolerance range having an upper and a lower limit between which lies the desired value, the arrangement being such that deviations within this range are ignored in forming the control signal, which is only produced when the range is exceeded to a greater than random extent. The random deviations may be damped or undamped. In the latter case the superimposition of a steady deviation on the random deviations causes a progressive increase in the magnitude and frequency of the deviations falling outside the upper or lower limit of the range and when this increase reaches a predetermined value a control adjustment is initiated to return the thickness to its desired value. The predetermined value of the progressive increase may be detected by a timing arrangement, e.g. when the deviation remains outside the upper or lower limit for a predetermined time, Fig. 5 (not shown), or by integrating the amount by which the deviation exceeds the limit, Fig. 6 (not shown), such integration being accomplished by charge and discharge of a capacitor. The embodiment shown in Fig. 8 uses a timing arrangement and comprises a relay arrangement 62 which provides a tolerance range whose limits are set by adjusting devices 95, 96 and which supplies a signal at output 63 or 64 when the deviation signal at 60<SP>1</SP> falls outside the upper or lower limit. The signal output from 63, 64 energizes a timer 67 which produces an output pulse after a predetermined period for application to AND gates 69, 70 also supplied by the signals from 63,64. If a signal and an output pulse occur simultaneously at an AND gate, a timer relay 73 or 74 is energized to close contact 75 or 76 for a predetermined time and so effect adjustment of the thickness. Contacts 75, 76 energize a motor 34 in one or other direction, which motor adjusts a variable gear interposed between the pair of adjusting rollers and their driving motor forming part of conventional control apparatus, Fig. 1 (not shown) for drawing individual slivers from cans and regulating the thickness of the combined sliver passing to the coiler plate. The outputs of the AND gates 69, 70 also supply a timer relay 77 which opens a contact 61 for a predetermined period after a control adjustment to isolate the deviation signal from 60<SP>1</SP> and so prevent further adjustment of the thickness during this period. Breakage of an individual sliver is signalled by a monitor 27 which operates a change-over switch 80, so that a signal from output 64 immediately  energizes a timer relay 81 to close contact 76 for a predetermined period and so return the thickness to its desired value. Timer relay 77 also operates after an operation of relay 81. The control circuit including members 27, 80 may be replaced by two relays respectively controlled by the outputs 63, 64 and responsive to a second  range of tolerance whose lower and upper limits correspond respectively to the deviation produced by the breakage of a sliver and by the elimination of the breakage, Figs. 3, 9 and 10 (not shown). In a modification employing damped random deviations Fig. 4 (not shown) the damping is so great that each overstepping of a tolerance limit causes and immediate adjustment of the extent of the drafting. Such damping may be achieved by inserting a capacitor 79 in the circuit of Fig. 8 or by inserting a damping component between the feeler and the deviation indicator, Fig. 1 (not shown). Members 80, 81 may be omitted and the motor 34 driven at either one of two speeds, the lower of which is selected by the switch 76 if there is no breakage and the higher by excitation of the relay 74 when a breakage occurs. The running time duration for the motor 34 is the same for each speed.