US 3930205 A
A circuit for controlling the operating parameters of an electronic yarn cleaner arrangement wherein the outputs of the amplifiers of a plurality of yarn cleaners are each connected through a switch and a resistor to a common point which is connected to one input of a comparator, the other input of the comparator being connected to a selectable reference voltage and the output of the comparator being connected to a regulator whose output collectively controls the amplification factor of all of the cleaner amplifiers. An indicating arrangement may also be associated with the comparator to indicate the degree of deviation, if any, from the desired reference.
Description (OCR text may contain errors)
United States Patent Aeppli 1 Dec. 30, 1975 ARRANGEMENTS FOR AUTOMATICALLY 3,048,817 8/1962 Greening 330/130 X JUST CORRECT REFERENCE 3,434,065 3/1969 Chu et a1. 330/127 X 3,488,604 1/1970 Smilowitz 1. 330/51 X VALUES FOR YARN FAULTS IN ELECTRONIC YARN CLEANERS Kurt Aeppli, Uster, Switzerland Assignee: Zellweger, Ltd., Switzerland Filed: Feb. 18, 1972 Appl. No.: 227,509
Foreign Application Priority Data Feb. 19, 1971 Switzerland 2427/71 References Cited UNITED STATES PATENTS 2/1950 Harris, Jr. 330/130 X Primary Examiner-James B. Mullins Attorney, Agent, or FirmCraig & Antonelli 57 ABSTRACT A circuit for controlling the operating parameters of an electronic yarn cleaner arrangement wherein the outputs of the amplifiers of a plurality of yarn cleaners are each connected through a switch and a resistor to a common point which is connected to one input of a comparator, the other input of the comparator being connected to a selectable reference voltage and the output of the comparator being connected to a regulator whose output collectively controls the amplification factor of all of the cleaner amplifiers. An indicating arrangement may also be associated with the comparator to indicate the degree of deviation, if any, from the desired reference.
10 Claims, 11 Drawing Figure TO DETECTOR PORTION OF CLEANER U.S. Patent Dec. 30, 1975 $75 5 Lo 2958 @0553 E ARRANGEMENTS FOR AUTOMATICALLY ADJUSTING CORRECT REFERENCE VALUES FOR YARN FAULTS IN ELECTRONIC YARN CLEANERS This invention relates to arrangements for automatically adjusting and correcting reference values for yarn faults in electronic yarn cleaners.
Electronic yarn cleaners having electromagnetic yarn cutters have been used to remove blemishes and other defects from yarns during spooling operations by severing the yarns. Yarn cleaners are used with textile winding machines of any type and serve to scan the yarn for uniformity and in the presence of an irregularity, such as constrictions, thickened portions, slubs, etc., delivers a control signal which is employed for cutting the yarn or for automatically cleaning the yarn at the location of the irregularity.
Electronic yarn cleaners necessitate a relatively accurate preadjustment of different parameters if they are to have the required cleaning effect. These parameters vary in dependence upon the measuring principle applied; that is, in capacitive yarn cleaners, allowance has to be made for material and moisture, while in the case of optical yarn cleaners, allowance has to be made for material, color, surface or twist.
In the past, allowance has been made for some of these parameters by preadjusting those parameters whose effect can be compensated by electrical values in the yarn cleaner to the original state by means of different adjusting means in a central apparatus. For example, it is possible to define a so-called material count which reflects the composition of the material and which can be used as a basis to preadjust the yarn cleaner to provide for the proper parameters.
However, a reference value such as this can undergo changes during the operation of a winding machine equipped with electronic yarn cleaners. Above all, the yarn count is prone to changes of this kind whether through certain fluctuations in count present in a given package or through the use during bobbin change of different packages with differences in the yarn count. There is also a danger of the operator omitting to carry out a setting which takes the count of the yarn to be processed into consideration with the result that considerable quantities of yarn with wrongly selected reference values may possibly be wound and cleaned. The effect of this is that the degree of cleaning is either too low, in other words, too few yarn faults are rejected, or alternatively too sharp, in other words, the yarn cleaners respond to even slight increases in thickness. The result is a yarn that has far too many knots.
Accordingly, there is a need to incorporate in the yarn cleaners presently provided in winding machines an automatic means of adjusting the yarn count to be processed which replaces manual monitoring and adaptation in a predetermined count range.
The present invention satisfies this need and provides a circuit arrangement for automatically adjusting correct reference values for yarn faults in electronic yarn cleaners, in which the outputs of the amplifiers of at least two yarn cleaners are connected together through a switch and a resistance and are applied to the input of a comparator which acts through a regulating device to change the degree of amplification of all the yarn cleaners in the sense that the voltage values at its input are directed towards a predetermined ideal value.
The comparator generates a reference voltage which corresponds to the particular reference value and with which the voltage value present at its input is compared. Depending upon the polarity of the difference signal, a regulator is controlled, increasing or reducing in stages the amplification of the connected yarncleaner amplifiers. The input of the comparator is preceded with advantage by a resistance-capacitor section which acts as a low-pass filter and which smooths the basically undulating signals arriving from the yarncleaner amplifiers.
In one advantageous embodiment, the circuit arrangement according to the invention is coupled to an indicator designed to show three phases of the input signal, for example, by means of indicating lights, as follows: (1) When the input signal corresponds to the reference voltage within predetermined limits, there is no readjustment of amplification and a first light signal is illuminated. (2) When the input signal is smaller than the reference voltage, amplification is increased by one stage and a second light signal is illuminated. (3) When the input signal is greater than the reference voltage, amplification is reduced by one stage and a third light signal is illuminated.
An embodiment of the invention will now be described by way of example with reference to the accompanying drawing which is a schematic circuit diagram of one form of the invention.
The arrangement illustrated in the drawing includes yarn-cleaner amplifiers l, 1", l" which have inputs connected to the detection portion of the respective yarn cleaners (not shown) and outputs providing the voltage values U U U,, connected to the operational portion of the cleaners (also not shown) and to the switches .2, 2" 2". These switches can be actuated either manually or automatically in conjunction with a mechanism for switching on a winding station. The switches 2, 2" 2" connect the outputs of all the amplifiers to a common point 4 through respective resistances 3', 3" 3". The common point 4 is connected to an adjusting unit 5 in which a capacitor 6 connected between point 6 and ground initially smooths the input signals. The adjusting unit 5 further includes a comparator 7 and a regulator 8.
A reference voltage which can be preselected by means of an adjusting member (not shown in detail) is applied to and compared with the input voltage in a comparator 7. The adjusting member may take the form of a potentiometer 7' connected to a voltage source and having its adjustable tap connected to the second input of the comparator. The resulting difference in voltage triggers a regulator 8 which, depending upon the polarity of the differential signal, transmits to a lead 9 an electrical voltage value which determines the amplification or gain of the yarn-cleaner amplifiers l, l" I". The regulator 8 can be in the form of, for example, a voltage divider whose tap is driven by a motor to an extent and direction dependent upon the size and polarity of the differential signal.
While the specific details of the yarn cleaners with which the present invention is associated have not been specifically described and illustrated herein, it should be understood by those of skill in this art that the invention is applicable to any conventional yarn cleaner, whether operating or capacitive, optical or other known detection principles, which provides a control signal to actuate the operational portion of the cleaner. The amplifiers I, l" I" are conventional amplifiers of thetype wherein the amplification factor is adjustable in response to.an applied control signal, i.e., a so-called variable'gain amplifier.
The differential signal can be additionally delivered by a lead l0.to an indicator board 11 having, for example, three indicators, such as signal lamps l2, l3, and 14, of which oneis provided for correct adjustment, a second for deviations to one side and .a third for deviations to the other side of the correct adjustment. Instead of or in addition to the signal lamps, it is also possible to use, for example, an indicating instrument in which the particular operational state of all the yarn cleaners connected to the point 4 can be recognized from the position of the pointer.
The circuit arrangement of the invention operates as follows: After a yarn has been inserted into one-of the yarn cleaners and the winding station subsequently started up, the switch 2 associated with the particular yarn .cleaner is closeduntil the comparator 7 has determined the difference, if any, between the measured voltage value derived from point '4 at the output of the amplifiers and the reference voltage and has adjusted the regulator'8 accordingly. After this testing operation, the switch 2 is reopened and the winding station continues to run withthe same degree of amplification to which it has been preadjusted. Only after another yarn has been inserted, whether at the same winding station or at a different winding station, is monitoring repeated through closure of the switch 2 associated with thatparticular winding station. From this there is derived the following operational advantages- I The amplification of all of the combined yarn cleaner amplifiers is adjusted in accordance with an average value of-the voltages'which they supply; as a result, each yarn cleaner has an equal influe'nce'upon the correction of the amplification ofthe respective cleaners. Thus, serious misadjustment' is prevented in the event of failure of the detecting unit 'of one of the yarn cleaners. 1
lfa yarn differing from those of the other winding stations is wrongly wound in one yarn cleaner, the reaction upon the remaining cleaners is slight, and so the sensitivity of the other cleaners remains within their required limits. In addition, if by contrast the reference least two yarn cleaners each having a variable gain amplifier providing an output control signal, a respective switch and resistance connected in series to the output of each amplifier and to a common point, comparator means for comparing the voltage at said common point with a reference voltage, and regulating means for regulating the gain of all of said amplifiers collectively in accordance with the difference between said reference voltage and the voltage at said common point as provided by said comparator means.
2. An arrangement as claimed in claim 1 wherein said comparator'means includes adjusting means for selectively adjusting the value of said reference voltage:
3. An arrangement as claimedjin claim 2,further including a low pass filter connected to said common point to smooth the voltage applied to the input of said comparator means. v
4. An arrangement as claimed in claim 2 wherein said adjusting means includes a potentiometer providing said adjustable reference voltage.
5. An arrangement as claimed in claim 4 wherein said regulating means includes a voltage divider having a movable tap providing a regulating signal for said amplifiers and 'means for adjusting the position of said tap in response to theoutput of said comparator.
6. An arrangement as claimed in claim 5, .further including indicating means connected to said comparator for indicating various ranges of deviation of the voltage at said common point from said reference voltage.
7. An arrangement as claimed in claim 6 wherein said indicating means includes a pluralityof indicators selectively energized to show the particular condition of the yarn in relation tothe reference value adjusted in said comparator means.
r 8. An arrangement as claimed in claim 1 wherein said regulating means includes a voltage divider having a movable tap providing a regulating signal for said amplifiers and means for adjusting the position of said tap in response to the output of said comparator.
9. An arrangement'as claimed in claim 1, further including a low pass filter connected to said common point to smooth the voltage applied to the input of said comparator means.
10. An arrangement as claimed inclaim 1, further including indicating means connected to said comparator for indicating various ranges of deviation of the voltage at said common point from said reference voltage.