US3631354A

US3631354A - Apparatus for the automatic adjustment of a yarn cleaner

Info

Publication number: US3631354A
Application number: US11461A
Authority: US
Inventors: Hermann Werffeli
Original assignee: Machinenfabrik Schweiter AG
Current assignee: Machinenfabrik Schweiter AG
Priority date: 1969-03-05
Filing date: 1970-02-16
Publication date: 1971-12-28
Anticipated expiration: 1988-12-28
Also published as: FR2034671A1; AT307933B; DE2005840A1; JPS543986B1; GB1270885A; CH490259A

Abstract

An apparatus for the automatic adjustment of a yarn cleaner at a winding machine, such yarn cleaner embodying at least one measuring cell, an amplifier and a pulse shaper. A signal feedback circuit electrically couples the output of the pulse shaper with the input of a control device which by means of its output signal brings about the adjustment of the amplification gain at the aforementioned amplifier. The signal feedback circuit embodies a pulse evaluation circuit which serves to generate an average value signal from a predetermined number of signals appearing at the output side of the pulse shaper.

Description

Inventor Appl. No.

Filed Patented Assignee Priority Hermann Werffeli Horgen, Switzerland Feb. 16, 1970 Dec. 28, 1971 Maschineufabrik Schweiter AG Horgen, Switzerland Mar. 5, 1969 Switzerland APPARATUS FOR THE AUTOMATIC ADJUSTMENT OF A YARN CLEANER [56] References Cited UNITED STATES PATENTS 3,132,407 5/1964 Glastra 28/64 3,476,329 11/1969 Felix 242/36 3,525,942 8/1970 Boronkay..... 328/2 3,488,604 III 970 Smilowitz 330/141 Primary Examiner- Donald D. Forrer Assistant ExaminerDavid M. Carter AnorneyWerner W. Kleeman ABSTRACT: An apparatus for the automatic adjustment of a yarn cleaner at a winding machine, such yarn cleaner embodying at least one measuring cell, an amplifier and a pulse shaper. A signal feedback circuit electrically couples the output of the pulse shaper with the input of a control device which by means of its output signal brings about the adjustment of the amplification gain at the aforementioned amplifier. The signal feedback circuit embodies a pulse evaluation circuit which serves to generate an average value signal from a predetermined number of signals appearing at the output side of the pulse shaper.

PATENTEU 0502a mu SHEET 2 OF 2 INVENTOR ATTORNEY APPARATUS FOR THE AUTOMATIC ADEUSTMENT OF A YARN CLEANER BACKGROUND OF THE INVENTION The present invention relates to a new and improved apparatus for the automatic adjustment of a yarn cleaner at a winding machine, this yarn cleaner being of the type incorporating at least one measuring cell, an amplifier and a pulse shaper.

All of the presently conventional electronic yarn cleaners possessing optical or capacitive measuring cell are manually adjusted to the yarn number which is to be processed, the amplification gain or factor at the yarn cleaner being adapted to the reference value.

However, in actual practice it has been found that it is virtually impossible to prevent an insufficient cleaning of the yarn because of too insensitive adjustment of the yarn cleaner, or, also, an exceptionally great number of errors because of too sensitive an adjustment. Thus, an exact and reliable adj ustment of the yarn cleaner was heretofore only associated with great difficulties. The causes of such are predicated upon a number of influences which are difficult to determine exactly, for instance, the yarn color and pronounced fluctuations of the surrounding light with optical measuring cells or changes in humidity or moisture with capacitive measuring cells, as well as because of the yarn characteristics, for instance, whether the yarn is smooth or rough, twisted or untwisted, and so forth.

SUMMARY OF THE INVENTION Accordingly, it is a primary object of the present invention to provide an improved apparatus for the automatic adjustment or regulation of a yarn cleaner which effectively overcomes the aforementioned drawbacks of the prior art constructions.

Another, more specific object of the present invention relates to an apparatus of the mentioned type which avoids the drawbacks of the known techniques for adjusting the yarn cleaners.

Yet a further significant object of the present invention relates to an improved apparatus for the automatic adjustment or regulation of a yarn cleaner in a relatively quick, reliable and accurate manner.

Now, in order to implement these and still further objects of the invention, which will become readily apparent as the description proceeds, the invention contemplates the provision of a signal feedback circuit which couples the output of the pulse shaper of the yarn cleaner with the input of a control device which by means of its output signal regulates the amplification gain at the amplifier. The signal feedback circuit embodies a pulse evaluation circuit serving to generate an average value signal from a predetermined number of signals appearing at the output of the pulse shaper. By virtue of these measures, it is now possible to employ the signals which appear because of yarn errors or defects at the output of the pulse shaper in the pulse evaluation circuit in order to form a signal average value which repeats at a certain spacing. The thus obtained control signal is used to bring about the control device automatically accommodates the adjustment at the amplifier of the yarn cleaner to the changes in the operating conditions which are characterized or symbolized by the average value signal, these operating condition changes being such, as for instance, increasing contamination of an optical measuring cell. In this manner it is possible in every instance and under all possible working conditions to achieve a uniform yarn cleaning quality.

BRIEF DESCRIPTION OF THE DRAWINGS The invention will be better understood and objects other than those set forth above, will become apparent, when consideration is given to the following detailed description thereof. Such description makes reference to the annexed drawings wherein:

FIG. I is a schematic block diagram of a preferred embodiment of inventive apparatus;

FIG. 2 is a detailed circuit diagram of the apparatus dcpicted in FIG. 1;

FIGS. 3 and 4! graphically illustrate the mode of operation of the apparatus depicted in FIG. 2; and

FIG. 5 is a graphic representation of the mode of operation of a variant of inventive apparatus.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Turning attention now to the drawings, in FIG. l the therein illustrated arrangement of a preferred embodiment of inventive yarn cleaner 1 will be seen to incorporate, in known manner, an optical or capacitive measuring cell 2, a controllable amplifier 3, a pulse shaper 4, a pulse evaluation circuit 5 and a yarn-cutting device 6. A control device of mechanism 7 is electrically coupled with the amplifier 3. This control device 7 serves to bring about variation of the amplification gain or factor at the amplifier 3. The input of this control device 7 is connected through the agency of a pulse evaluation circuit 8 with the output of the pulse shaper 4, thus rendering possible a signal feedback.

Now, if a yarn is deposited in the measuring cell 2 of the yarn or thread cleaner 1, then, as shown by the curve 9 in FIG. 3, a voltage surge appears at the output of the measuring cell 2, this signal appearing amplified in shape at the output of the pulse shaper 4. Such signal then possesses an amplitude of the corresponding voltage peak and a constant width and is proportional to the yarn cross section. Now, from the output of the pulse shaper 4 this signal, on the one hand, is delivered to the evaluation circuit 5 which is in the form of a threshold switching mechanism possessing an adjustable response threshold as a function of a percentage of the amplitude of the arriving signal and from such location is delivered to the yarn separating or cutting mechanism 6 and, on the other hand, the aforementioned signal at the output side of the pulse shaper 4 is also delivered to the pulse evaluation circuit 8.

The pulse evaluation circuit 8 embodies an integrator and prestorage device 10, a counter 11 and a main storage device 12. The signals delivered from the pulse shaper 4 and which are determined in number by the counter mechanism 11 are integrated and stored in the integrator and prestorage device 10, in order to thereby form an average value from the number of pulses which have been predetermined by the counter mechanism 11. This average value signal then is fed to the main storage device 12 where it stands in readiness as a base value and can be extinguished by a signal from the counter II and replaced by a new average value signal, as such will be described in greater detail hereinafter.

As will be likewise explained, in greater detail hereinafter, the average value signals arrive from the output of the main storage device 12 at the control device 7 which, because of voltage differences between successive average value signals, adjust the amplification gain at the amplifier 3 in such a manner that the relationship between the average base amplification and the fixedly adjusted threshold value at the threshold value circuit 5 and therefore the sensitivity of the yarn cleaner 1 remains constant.

The aforedescribed arrangement will now be discussed in greater detail with respect to the more specific circuit diagram of FIG. 2. Initially it is mentioned that the yarn F is automatically inserted in the measuring cell 2 through the action of suitable means of known construction provided at the winding machine. Consequently, as previously explained, there appears at the output of the amplifier 3 a voltage surge U,.

In order to shape this voltage surge into a useful signal the pulse shaper 4 provided for this purpose embodies a switch at which can be actuated by the aforementioned control means of the winding machine, and which switch is opened for a predetermined time according to the amplitude of the curve 13 in FIG. 3. In this time period the voltage U can charge a switch e in the aforedescribed manner at the threshold evalua tion circuit 5 and the pulse evaluation circuit 8 (FIG. 1). The closing time of the timing switch e which is likewise controlled by the automatic control mechanism of the winding machine is represented by curve 17 in FIG. 3. Consequently, at the input of the pulse evaluation circuit 8 there appears the pulse represented by curve 18 in FIG. 3 and having the voltage U After delivery of this pulse to the pulse evaluation circuit 8 the switch d closes according to the curve 13 of FIG. 3, whereupon the capacitor 14 of the pulse shaper 4 is discharged.

As will now be readily apparent, the pulse which has been generated in.the aforedescribed manner and delivered to the pulse evaluation circuit 8, which pulse is represented by curve 18 in FIG. 3, is proportional to the cross section of the yarn F inserted into the measuring cell 2.

As already mentioned, the pulse evaluation circuit 8 cmbraces a counter mechanism 11 (FIG. 1) which counts a predetermined number of incoming pulses. According to the arrangement shown in FIG. 2, this counter mechanism or counter 11 is formed from a number of binary units 19 which provide a so-called frequency divider. After the pulse has passed through the last binary unit 19 the pulse can be amplified in a suitable amplification device 20 in order to then arrive at a timing element 21.

The last-mentioned timing element 21 is capable of delivering, in accordance with a predetermined program, three signals via the

outputs

22, 23 and 24, as such will be described in greater detail hereinafter.

Considering FIG. 2 further, it will be seen that the input signal U arrives parallel to the counter mechanism 11 at the prestorage device 10, which according to this figure, possesses a suitable transducer 25 which converts the input voltage U into a proportional current and delivers such in the form of a pulse. The pulses which follow one another then charge a subsequently arranged capacitor 26 which serves as the prestorage device. Then, as the output signal there appears at the output side of the integrator and prestorage device 10 the signal U.. which has been amplified by the impedance matching device 27, as such has been graphically represented by the curve 38 in FIG. 4. In other words, curve 38 represents the number of added pulses U; of the curve 29 shown in FIG. 4. When the contact of switch f is closed this output signal U appears at the capacitor 28 of the main storage device 12, the stored additive value of which is thus directly proportional to the sought for average value.

After the succession of pulses U have passed through the frequency divider 19-19, then the running of the program of the timing element 21 begins, by means of which the switch a connected parallel to the capacitor 28, the switch b disposed parallel to the capacitor 26 and the switch f are actuated.

More specifically, by virtue of the output signal appearing at the conductor or line 22 initially the switch a is closed, resulting in extinguishment of the main storage device capacitor 28. This switching operation is represented by curve 39 in FIG. 4. Thereafter, the switch f is closed via the conductor 23, leading to transmission of the sum or additive voltage of the prestorage device capacitor to the main storage device capacitor 28, and which switching operation has been represented by the curve 30 of FIG. 4. Now, by means of the conductor 24 the switch b is also closed, and thus, the stored value in the capacitor 26 is extinguished, as such has been represented by curve 31 of FIG. 4. Then, a new cycle of forming the average value begins.

As will be apparent by referring to the curve 32 of FIG. 4, after the transmission of the sum or additive voltage from the prestorage device capacitor 26 to the main storage device capacitor 28 there appears at the output thereof formed by a suitable impedance matching device 33 functioning as an amplifier, a signal with the voltage U which is proportional to the average value formed from the predetermined number of voltage pulses. This signal U is then delivered to the previously discussed control device or mechanism 7, which can be constructed as a bridge or thermistor. Now, if the signal U formed from an average value possesses a voltage which is different from the signal produced from the preceding average. value, then, in known manner, via the control device 7 there occurs an adjustment of the amplification gain at the amplifier 3 of the yarn cleaner 1.

When changing the yarn quality which is to be processed or, for instance, the yarn number, and to prevent too large a loss in time due to the self-regulating efi'ect of the apparatus by virtue of forming a multiplicity of average values and therefore to prevent the removal of a corresponding large number of yarn ruptures, the control device 7 is advantageously equipped with a parallelly connected manually operated precontrol device 34 which initially enables carrying out a coarse adjustment of the amplification gain at the amplifier 3 corresponding to the yarn quality or yarn number, respectively.

With the previously described embodiment of the invention there was mentioned that the contacts or switches d and e at the yarn cleaner (FIG. 2) are controlled by the means for inserting the yarn F in the measuring cell 2. The previously described apparatus additionally only responded when a yarn was inserted and, thus, a voltage surge according to curve 9 of FIG. 3 was generated. Naturally, it is however also possible to use the signals generated by a yarn passing through the measuring cell 2 for pulse evaluation and feedback in the aforedescribed manner. Such signals which are produced by the through passing yarn, or the like, at the output of the amplifier 3 of the yarn cleaner are illustrated in curve 35 of FIG. 5. In order to obtain pulses therefrom, which enables a further processing in the aforementioned manner, it is only necessary to actuate the switches d and e by means of a nonillustrated pulse transmitter, whereby the switch d is periodically closed for a predetermined period of time and by integration the voltage value U according to the curve portion 36 of FIG. 5 can be obtained. In this FIG. 5 the closing time of the contact or switch d is illustrated by the curve 37. On the other hand, curve 15 again illustrates the charging operation of the capacitor 14 to the voltage U whereas the curve 17 depicts the switching time of the contact or switch e, and finally, the curve 18 illustrates the pulse delivered to the pulse evaluation circuit 8.

From what has been described heretofore it should be readily apparent that there is provided a device or apparatus for the automatic regulation of the sensitivity of the yarn cleaner which is far superior to the previously employed practice of manual adjustment. Dye to the continuous formation of the average values from a predetermined number of pulses and the feedback of such average value signal there is obtained a continuous accommodation or adjustment of the apparatus to the changing operating conditions. Consequently, there is obtained a yarn cleaning apparatus which is accommodated to every requirement which occurs during practice.

While there is shown and described present preferred embodiments of the invention, it is to be distinctly understood that the invention is not limited thereto, but may be otherwise variously embodied and practiced within the scope of the following claims. ACCORDINGLY,

What is claimed is:

I. In combination with a yarn cleaner of a winding machine which yarn cleaner is of the type incorporating at least one measuring cell. an amplifier and a pulse shaper, an apparatus for the automatic adjustment of such yarn cleaner which comprises a control device electrically coupled with said amplifier, a signal feedback circuit electrically coupling the output of said pulse shaper with the input of said control device, the output of said control device being used for adjusting the amplification gain of said amplifier, said signal feedback circuit comprising a pulse evaluation circuit for generating an average value signal from a predetermined number of signals appearing at said output of said pulse shaper.

2. The combination defined in claim 1, wherein said pulse evaluation circuit embodies a pulse counter mechanism, an integrator and prestorage circuit means and a main storage circuit means.

3. The combination defined 2, claim 1, wherein said output of said pulse shaper of the yarn cleaner is electrically coupled with the input of said integrator and prestorage circuit means as well as with the input of said pulse counter mechanism.

4. The combination defined in claim 3, wherein the output of said pulse counter mechanism is electrically coupled via control conductor means with both said prestorage circuit means and said main storage circuit means, in order to transmit a prestored signal from said prestorage circuit means to said main storage circuit means and for extinguishing the signals stored in said prestorage circuit means and said main storage circuit means.

5. The combination defined in claim 4, wherein said prestorage circuit means and said main storage circuit means incorporate respective switch means, said control conductor means being electrically coupled with said switch means.

6. The combination defined in claim 5. wherein said prestorage circuit means includes a capacitor connected in parallel with a switch means thereof, and wherein said main storage circuit means includes a capacitor connected in parallel with a switch means thereof.

7. The combination defined in claim 4, wherein said pulse counter mechanism includes an output side formed by a timing element for the programmed control of the output signals thereof via said control conductor means.

8. The combination defined in claim 1, wherein said control device comprises a bridge arrangement.

9. The combination defined in claim 1, wherein said control device comprises a thermistor.

10. The combination defined in claim 1, further including a manually actuated precontrol device connected in parallel with said control device.

11. The combination defined in claim 2, wherein said pulse counter mechanism comprises frequency divider means formed by a number of bistable units.

12. The combination defined in claim 1, wherein said pulse shaper of said yarn feeler is capable of being controlled by said winding machine.

13. The combination defined in claim 1, further including pulse transmitter means for controlling said pulse shaper of said yarn cleaner.

Claims

1. In combination with a yarn cleaner of a winding machine which yarn cleaner is of the type incorporating at least one measuring cell, an amplifier and a pulse shaper, an apparatus for the automatic adjustment of such yarn cleaner which comprises a control device electrically coupled with said amplifier, a signal feedback circuit electrically coupling the output of said pulse shaper with the input of said control device, the output of said control device being used for adjusting the amplification gain of said amplifier, said signal feedback circuit comprising a pulse evaluation circuit for generating an average value signal from a predetermined number of signals appearing at said output of said pulse shaper.

3. The combination defined in claim 2, wherein said output of said pulse shaper of the yarn cleaner is electrically coupled with the input of said integrator and prestorage circuit means as well as with the input of said pulse counter mechanism.

6. The combination defined in claim 5, wherein said prestorage circuit means includes a capacitor connected in parallel with a switch means thereof, and wherein said main storage circuit means includes a capacitor connected in parallel with a switch means thereof.