EP0286049B1 - Method and apparatus for controlling the production and quality of the working stations at multispindle textile machines - Google Patents

Description

There are a large number of production machines in the textile industry on which a large number of production sites are used at the same time. Spinning machines, winding machines or twisting machines can be cited as examples. There is an obvious need to automatically monitor each and every one of these manufacturing sites for production flow and quality. From the point of view of the production process, above all, thread break monitoring is desired, and from the point of view of quality monitoring, the determination of the thread cross-section and / or its unevenness. In the case of twisting machines, the cross-section of the twine is of particular interest to check whether all threads are twisted.

Even if "thread" is always mentioned in the following explanations, this term should not be understood as restrictive, but as representative of all spinning products, such as yarns, rovings, slips, twists, filaments and the like.

The above-mentioned monitoring of all individual production sites can be technically solved by known means, but has not yet been implemented for reasons of cost. The large number of production sites allows only a minimal cost per production site, so that the effort per machine remains within a reasonable range.

For thread break detection on ring spinning machines, systems are known, for example from DE-A-35 06 013, which have so-called traveling sensors, each of which sweeps over the entire side of the machine. Because a thread break is a relatively rare event, this solution for thread break detection is justifiable. On the other hand, it is not possible to measure other thread parameters because the signal component per individual thread is far too low to be able to make a statistically relevant statement about quality features such as thread cross-section and / or thread unevenness. Such a monitoring could not be called an on-line method, but would only be a random check as it is already carried out in the laboratory today and is to be replaced by the monitoring directly at the production sites.

The invention is now to provide a device which enables production and quality monitoring of the production sites at a reasonable cost and which also responds sufficiently quickly.

The invention relates to a device for production and quality monitoring of the production sites on multi-spindle textile machines, in which the production sites are arranged in rows and the thread running at each production site occupies an at least approximately extended position in the monitoring area, with a monitoring organ assigned to several production sites, with a transmitter and a receiver through which a beam of rays which is movable relative to the production points and oriented transversely to the direction of the thread runs.

The device according to the invention is characterized in that a common monitoring device is provided for a group of at least two production sites and that its radiation beam is only moved within this group and across the connecting line of the individual production sites and is shaded by the thread of a production site, whose size measured from the receiver forms a criterion for the presence of the thread in question and / or a measure of the size of its diameter.

The basic idea of the invention is therefore to use neither a monitoring device for each production site nor a common traveling sensor for the entire side of a machine, but to provide a monitoring device for a group of production sites.

The bundle of rays is preferably oriented obliquely to the connecting line of the individual production points and thus strikes the threads at the individual production points one after the other, so that successive shading impulses occur. It is essential for the accuracy and meaningfulness of the measurement that only one thread crosses the ray bundle at a certain point in time, i.e. that the individual shading pulses are clearly separated from one another and can therefore be clearly assigned to the respective production site.

The size of the groups is a matter of discretion and is determined by practical parameters. For example, the frequency of the scanning of a certain production site has an influence and it should also be noted that the light intensity may no longer be sufficient if the transmitter and receiver are at greater distances. The latter of course does not apply to laser beams.

Fig. 1

einen schematischen Grundriss einer Anzahl von Produktionsstellen und einer zugeordneten Ueberwachungseinrichtung einer Textilmaschine,

Fig. 2

ein Impulsdiagramm zur Funktionserläuterung,

Fig. 3,4

ein erstes Ausführungsbeispiel einer erfindungsgemässen Ueberwachungseinrichtung in zwei Ansichten,

Fig. 5,6

je eine Variante der in Fig. 1 dargestellten Anordnung; und

Fig. 7,8

ein weiteres Ausführungsbeispiel einer erfindungsgemässen Ueberwachungseinrichtung in zwei Ansichten.

The invention is explained in more detail below on the basis of exemplary embodiments and the drawings; shows:

Fig. 1

1 shows a schematic plan view of a number of production sites and an associated monitoring device of a textile machine,

Fig. 2

a pulse diagram to explain the function,

Fig. 3.4

a first embodiment of a monitoring device according to the invention in two views,

Fig. 5.6

each a variant of the arrangement shown in Fig. 1; and

Fig. 7.8

a further embodiment of a monitoring device according to the invention in two views.

Fig. 1 shows a schematic floor plan of eight production points of a multi-spindle textile machine, symbolized by eight threads 1 to 8 running through these production points perpendicular to the plane of the drawing. These production points are assigned a common monitoring device which has a transmitter S for a light beam L and a receiver E for this having. Transmitter S and receiver E are arranged such that the light bundle L forms an acute angle a with the connecting axis H of the production sites 1 to 8 arranged in a row.

If all eight production sites 1-8 are now to be monitored with the single monitoring device S, E, L shown, then the light beam L must continuously scan the individual production sites with a certain frequency. This scanning takes place in that transmitter S and receiver E and thus also the light beam L, or in other words, the monitoring device, from the initial position S, E, L drawn in full lines in the direction of arrow P into the end position Sʹ shown in dashed lines, Eʹ, Lʹ can be moved.

At a small angle a, the path in the direction of arrow P is relatively small, so that scanning in a rapid sequence is possible. This differs from a solution with a = 90 °, i.e. movement of the transmitter and receiver along the connecting axis H.

As soon as during the described movement, which preferably takes place at a constant speed, the light bundle L strikes one of the threads 1-8 and is crossed by it, a shading pulse I arises at the receiver E. FIG. 2 shows a corresponding pulse diagram, in which on the The time t between the starting and end positions T1 and T2 of the monitoring device and the ordinate the shading A, which results from the threads 1 to 8, is plotted on the abscissa. Each shadowing by one of the threads 1 to 8 is symbolized by a shading pulse I1 to I8. The size of the shading I1 to I8 is a measure of the diameter of the thread in question. If there is no thread at the production site concerned, for example because of a thread break, then there is no shadowing and no shading impulse is registered.

This is indicated in FIG. 2 on the basis of the shading pulse I3 shown in broken lines. If this does not occur, then this means that there is no thread at the production site 3. Thus, in the manner described, a whole series of threads can be monitored with a single monitoring element, and not only for thread breakage, but because of the relationship between the size of the shade A and the thread diameter, also for properties related to the thread diameter, such as, for example, unevenness and the like .

If the described movement of the monitoring device S, E, L takes place periodically, then each production site and each of the threads 1-8 is scanned with a certain frequency. Since the threads have generally moved between two scans, a different thread location is always scanned. The known quality parameters, such as the coefficient of variation of the unevenness, the spectrogram, etc. can be calculated from a sufficient number of sampling points. A complete pulse sequence is not necessary for this. Rather, interruptions are permissible because there is enough material and time for the evaluation in an "on-line" measurement of the type described.

In the case of twine, control of the presence of all individual threads is necessary in various cases. If a single thread is missing or if there is an excess thread, the diameter of the thread changes and with it the shading. From this it can be determined whether the number of individual threads in the thread is correct.

It is also conceivable that a different thread count is produced by a mix-up at a production site. In this case, there is always a different shade from the production site in question than with a thread of the right fineness. This means that even production sites with incorrect thread count can be identified.

If the size of the shading is included in the evaluation, it is not only cost-effective to do a thread break detection, but also to achieve comprehensive quality monitoring of each individual production site.

The number of production sites assigned to a common monitoring device S, E, L (FIG. 1) is variable within wide limits and the number of eight such production sites selected as an example is rather at the lower limit. Of course, for economic reasons one will try to assign as many production sites as possible to a monitoring body, the number of which is limited by the security of the assignment of an impulse to the corresponding production site. In this context, this means that the shading impulses caused by the individual production sites must be clearly separated from each other. Because only then can each shading pulse I be uniquely assigned to the associated production site.

Since this depends on several parameters, for example on the angle a between the light beam L and the connecting axis H of the production sites 1-8 (FIG. 1), on the sampling frequency and on the diameter of the light beam L, no binding information can be given about the number of the a single monitoring body can be used to make production sites safe and clearly monitorable. As a rule, however, this should certainly be 16 production locations. In a machine with, for example, 160 production sites, 10 groups of 16 production sites would have to be formed. With the individual groups, only a minimal effort is necessary because the evaluation is preferably carried out centrally. In this way, inexpensive systems can be built.

The number of production sites can be further limited by problems with the optics, since the light intensity with the square of the distance from the receiver decreases to the transmitter. Disturbing light and noise can cover up the useful signal. A considerable improvement is possible if the light is modulated in a known manner. External influences can thus be eliminated.

Some exemplary embodiments of a movable monitoring device are explained below. FIGS. 3 and 4 show a first embodiment of this type, FIG. 3 showing a view of a thread row of a production machine in the direction of the connecting axis H of FIG. 1, and FIG. 4 showing a view in the direction of the arrow IV in FIG. 3.

As shown, the threads 1 to 8 are arranged in a row along a straight line, as in FIG. 1. On one side of this group of production sites and threads, in FIG. 4 on the left, there is a swivel arm 9 carrying the transmitter S and on the other side a corresponding swivel arm 10 carrying the receiver E is arranged. Each swivel arm is mounted on a corresponding stationary axis 11 or 12 and the connecting line between these axes runs like the light beam L in FIG. 1 at an angle to the row of threads 1-8. If the two swivel arms 9 and 10 are pivoted simultaneously and in the same direction into the position shown in dashed lines, the movement of the transmitter, receiver and light beam indicated in FIG. 1 takes place from the position S, E, L into the position Sʹ, Eʹ, Lʹ and the described scanning of the individual production sites occurs.

FIG. 5 shows a schematic plan view of a variant of the arrangement shown in FIG. 1, in which only the transmitter S, but not the receiver E needs to be moved. The prerequisite for this is that the stationary receiver E is at a relatively large distance from the neighboring production site 8, and that the path of movement of the transmitter S is approximately twice as large as in the arrangement of FIG. 1. Only half of the elements need transmitters for this S and receiver E to be moved, and in particular there is no synchronization of the movement of transmitter S and receiver E. In principle, it applies to all examples that the transmitter and receiver can be interchanged.

FIG. 6 shows a schematic plan view of a further variant of the arrangement from FIG. 1, in which a mirror is used to reflect the light beam L. According to the illustration, the transmitter S and receiver E are arranged on one side of a thread row 1-8 to be monitored, and on the other side there is a pivotable mirror 13. In the starting position of the monitoring element S, E, L the light beam L emitted by the transmitter S thrown by the mirror 13 in its position shown in full lines as a reflected beam L1 onto the receiver E, the reflected beam L1 not yet crossing the thread 1. However, if the mirror 13 assumes the position shown in broken lines, a light beam Lʹ emitted by the transmitter S reaches the receiver E as a reflected beam L1ʹ and does not cross the thread 8 any longer.

It can be seen from this that when the mirror 13 swivels between the two positions shown, the light beam reflected by the mirror 13 onto the receiver E undergoes a continuous displacement between the two positions L1 and L1ʹ and the threads 1 in the process up to 8 of the thread row to be monitored. The required pivoting or rotating movement of the mirror 13 is extremely small compared to the adjustment paths of the transmitter S and / or receiver E required in the arrangements shown in FIGS. 1, 3, 4 and 5. Such small movements do not necessarily require a mechanical drive, but can also be carried out quasi-mechanically, for example by means of bimetal or piezo bending rods.

Of course, based on the exemplary embodiments described, a person skilled in the art still has a whole series of options for having a light beam sweep across a row of threads by means of a moving light source and / or mirror. In particular, options are particularly interesting in which a special moving part is not required for the movement of the light beam, but rather an existing movement of the textile machine can be used.

Such an arrangement is shown in FIGS. 7 and 8. 7 shows a view in the direction of the axis H (FIG. 1) of a thread row to be monitored in the area of the so-called front cylinder of a ring spinning machine, and FIG. 8 shows a view in the direction of the arrow VIII in FIG. 7.

According to the illustration, the threads 1 to 8 are guided over the rotatably driven front cylinder 14 of the drafting system and lie in a defined plane in the monitoring area. In principle, the monitoring device has the structure shown in FIG. 6 with transmitter S, emitted light beam L, reflected light beam L1, moving mirror 13 and receiver E the difference that transmitter S and receiver E are arranged on different sides of the thread row 1-8, and that the plane spanned by the emitted and reflected light beam L or L1 runs obliquely to the plane of the threads 1-8.

The mirror 13 is fixedly mounted on the front cylinder 14, preferably at a gradation or at another suitable location, and rotates with the front cylinder 14 and reaches the emitted light beam L with each revolution for a certain period of time and reflects this as light beam L1 Receiver E. Since the mirror 13 continues to rotate during this period, the individual threads 1 to 8 are scanned as described with reference to FIG. 6.

In order to avoid adjustment problems with the transmitter S and receiver E, the mirror 13 is preferably designed as a spherical cap.

In the exemplary embodiments described, known elements, for example luminescent diodes or photodiodes, are used as transmitters and receivers. The processing of electrical impulses is well known and therefore need not be described in detail. However, it should be mentioned that the shading represents a voltage or a current pulse. Both sizes are easy to measure and can easily be converted into binary signals and are therefore ideally suited for further processing by means of electronic data processing, preferably microprocessors.

Claims (10)

1. Production and quality monitoring apparatus for the production points (1-8) of multi-spindle textile machines, in which the production points are disposed in a line and the thread running at each production point adopts an at least approximately straight position in the monitoring region, having a monitoring element (S, E, L) associated with a plurality of production points, having a transmitter and a receiver, extending through which is a ray beam (L) which is movable relative to the production points and is oriented transversely to the thread running direction, characterized in that a common monitoring element (S, E, L) is provided for each group of at least two production points (1-8) and that during monitoring the ray beam (L) of said element is movable only within said group and transversely to the connecting line (H) of the individual production points (1-8) and experiences shading by the thread of each production point, the value of said shading measured at the receiver forming a criterion for the presence of the thread in question and/or a measure of the size of its diameter.
2. Apparatus according to claim 1, characterized in that the ray beam of the monitoring element (S, E, L) is oriented obliquely to the connecting line (H) of the individual production points (1-8).
3. Apparatus according to claim 2, characterized in that the ray beam (L) is moved at a constant speed transversely to the thread running direction, so that equidistant shading pulses (I) arise at the receiver (E).
4. Apparatus according to one of claims 1 to 3, characterized in that the amplitude (A) or the time length of the shading pulses (I) or a combination of both is used to monitor the cross-section of the thread in question.
5. Apparatus according to claim 3, characterized in that the transmitter (S) and the receiver (E) are arranged so as to be movable transversely to the thread running direction, and that said movement is effected simultaneously and in synchronism.
6. Apparatus according to claim 5, characterized in that the transmitter (S) and receiver (E) are each carried by a drivable swivel arm (9 and 10 respectively).
7. Apparatus according to claim 3, characterized in that the receiver (E) is disposed in a stationary manner and the transmitter (S) is arranged so as to be movable.
8. Apparatus according to claim 7, characterized in that transmitter (S) and receiver (E) are arranged in a stationary manner, and that the movement of the ray beam (L) is effected by means of an adjustable mirror (13).
9. Apparatus according to claim 8, characterized in that the transmitter (S) and the receiver (E) are disposed at one side and the mirror (13) is disposed at the other side of the production points (1-8) to be monitored.
10. Apparatus according to claim 8, characterized in that the transmitter (S) and the receiver (E) are disposed at different sides of the production points (1-8) to be monitored, and that the mirror (13) is carried by a rotatable part, preferably a roller (14) for the threads in question.

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