Patent Application
20140167730
The present invention relates to a method (and corresponding textile machine) for monitoring contact of a rotating component of a textile machine, in particular of a clothing roller of a card, for example of a card cylinder, with a further component of the textile machine, wherein the two components are connected to an electric power source, but usually are electrically isolated from each other. Only in the event of a contact between the two components, a short-circuit is generated that is detected by a monitoring device.
In DE 10 2006 002 812 A1, a generic device and a corresponding method are described. In a spinning preparation machine, in particular a card, carding machine, or the like, in which a clothed fast-rotating roller is arranged opposite to at least one clothed and/or non-clothed component and the spacing between the opposing components is changeable, it is provided for monitoring and/or adjusting of spacings at the components that the components are electrically insulated with respect to each other. As respective contact elements, these components are connected to an electrical circuit in which a measuring element for contact detection is integrated. The clothed fast-rotating roller is, for example, a card cylinder, wherein the opposing clothed and/or non-clothed component are/is, for example, a doffer roller, a flat or a casing segment that has a guiding surface. Between the roller and the component arranged spaced apart therefrom, there is the so-called carding gap. This carding gap is very narrow and can change during the operation due to the components heating up. This can result in contacts between the fast-rotating roller and the opposing component. Such contacts are to be avoided whenever possible.
Accordingly, DE 10 2006 002 812 A1 proposes to avoid undesirable frequent contact between the components and therefore to avoid damage to the clothing by determining the number of contacts, as a result of which an indication or reaction in the case of only one of these contacts or only a few contacts is avoided. In particular, an undesirable shutdown of the machine is avoided in this manner. In order to achieve this, an evaluation of the number of contacts of a certain contact duration, e.g., a contact duration of 0.1 ms, 1 ms or 2 ms is filtered. For this purpose, a counting device is provided which determines the number of contacts per time unit between a card clothing and a clothing strip. This number or amount of contacts is used for further evaluation and for the reaction resulting therefrom, for example, for stopping the card or for continued operation of the card.
A disadvantage of this solution is that each individual tooth of the clothing generates an individual contact with the opposing component and therefore increases the number of contacts. The technical implementation of this proposal is very complicated. In particular, for a component that is arranged opposite to the clothed card cylinder and is also provided with a clothing, it is necessary to monitor each individual clothing needle in terms of its potential so as to be able to detect the number of contacts. Apart from that, determining the number or amount of contacts would not be possible since a short contact with this clothing-covered component would already indicate a single contact in the same manner as it would indicate continuous contacting of both components across a plurality of clothing tips. This very inaccurate or else very complicated determination of the number of contacts is hardly implementable in practice.
It is therefore an object of the present invention to enable simple and particularly effective monitoring of contacts between components of a textile machine that have approached each other, so as to be able to draw corresponding conclusions on the further operation of the textile machine. Additional objects and advantages of the invention will be set forth in part in the following description, or may be obvious from the description, or may be learned through practice of the invention.
The method according to the invention serves for monitoring contacts of the rotating component of a textile machine, in particular of a clothing roller of a card, for example of a card cylinder, with a further component of the textile machine. The two components are connected to an electrical power source. Normally, i.e., when both components are not in contact with each other, they are electrically isolated from each other. Only in the case of contact between the two components, a short-circuit is generated that is detected by a monitoring device.
According to the invention, not the number of individual short-circuits is detected, but the duration of individual short-circuits per time unit is detected and summed up to form a total duration of all short-circuits per time unit. This has the substantial advantage that a kind of quality assessment can take place with regard to an actual risk of damage to the textile machine due to excessive contacts. In particular, if only individual short contacts and only a few contacts take place between opposing components, normally, no danger to the machine is to be expected. Such short contacts can occur if fiber contaminants, for example, small metal particles temporarily adhere between the two opposing components and subsequently disengage again and are conveyed out of the machine. Also, if individual teeth of the clothing or clothings generate a short-time contact, they normally grind each other down within a very short time so that in the future no further contact is generated therefrom. However, if, for example, excessive heating of the card cylinder generates a long lasting contact between the two opposing components, this can be a massive threat to the machine. For example, during a long lasting time period of short-circuits it can be derived therefrom that there is a more severe danger for the machine than during only short-term contacts or short-circuits per time unit.
Also, the particular advantage of the invention is that even in the case of clothing teeth that oppose each other, the teeth do not have to be detected individually in order to determine the number of contacts; rather, each of the individual components can be provided with only one opposite pole. This results in a short-circuit even if there is a multiplicity of contact points in this component. Thus, the present invention can be used in a particularly advantageous manner, for example, for a card cylinder and the clothed flat bars or clothed rollers opposite to the card cylinder.
The present invention can also be used if the clothed rotating card cylinder faces a flat component, for example, a shielding or guiding device. In all these cases, the contact duration is to be determined, independent of the number of contacts, so as to enable therefrom particularly effective monitoring with regard to a potential danger to the textile machine.
In an advantageous embodiment of the invention, the duration of one revolution of the rotating component or a fraction or a multiple of the duration of this revolution is used as the time unit which is used for evaluating the duration of individual short-circuits or the total duration of all short-circuits. In this manner it can be determined that there is a certain contact duration per revolution of, for example, the card cylinder. If this contact duration exceeds a predetermined admissible contact duration, adequate measures can be initiated such as, for example, shutting down the textile machine or adjusting the spacing between the components opposing each other.
It is advantageous if, from the total duration of the short-circuits per time unit and the time unit itself, a quotient is formed. This quotient, which implies that in the case of a high value, long lasting contacting between the components took place and that in the case of a low value, this duration of contacting was rather short, can be used for the monitoring device or a correspondingly allocated evaluation unit as a measure for measures to be taken.
The quotient from the total duration of the short circuits per time unit and the time unit itself is advantageously to be used a measure for the quality of the setting of the textile machine. For example, it can well be acceptable that a low value of this quotient indicates a particularly good setting of the textile machine, whereas if the quotient is zero, the spacing between the components opposing each other is possibly too large. However, if the value of this quotient is very high, this indicates that the gap between the components opposing each other is too small and that contacting takes too long, resulting in danger to the machine. An acceptable value for the quality of the setting of the textile machine and the corresponding quotient may result from the experience of the operator of the textile machine or from the type of the components that face each other and are monitored. Thus, for example, a somewhat higher quotient can be accepted for clothing wires which are configured elastically, whereas for stationary guide walls or fixed all-steel clothings, the value has to be lower so as to rule out damage.
When exceeding a predetermined total duration of the short-circuits of a time unit and/or the value of the quotient from the total duration and the time unit itself, an advantageous measure can be that the rotating component and/or the further component are/is machined, in particular by grinding. By grinding, very fine material removal can be achieved and consequently, very fine adjustment of the components opposing each other can be carried out.
An advantageous other or additional measure when exceeding the duration of individual short circuits and/or the total duration of all short-circuits per time unit and/or the quotient can be that the spacing between the rotating and the further component is increased. However, it has always to be ensured that this does not seriously jeopardize the quality of the fiber material to be processed since normally a particularly narrow carding gap produces a better quality than a larger carding gap.
Preferably, the duration of individual short-circuits per time unit and/or the quotient from the total duration of all short-circuits per time unit and the time unit itself is displayed on a display device. In this manner, the operator of the textile machine is able to initiate suitable measures for adjusting the machine if the corresponding value is unsatisfactory.
In a particularly advantageous configuration of the invention, the rotating and/or the further component are/is divided along an axis of the rotating component into axial sections that are electrically isolated from each other. In particular, in the case of stationary components, it is possible in a very simple manner to isolate them from each other in sections transverse to the rotational direction of the rotating component. These sections, that are isolated from each other, can be analyzed independently of each other with regard to their contact duration. In this manner, measures to be taken can be localized more easily. Thus, for example, it is possible to detect that the sag of the stationary component is too great if the contact duration in the middle of the stationary component is longer than in the lateral regions. As a possible measure in this example, adjusting the sag of the component or machining the component may be carried out only in the middle region.
A textile machine according to the invention is suitable for carrying out the above-mentioned method. The textile machine comprises in particular a clothing roller of a card, for example, a card cylinder, which is arranged spaced apart from a further component of the textile machine by a small gap, for example, a carding gap. The two components are connected to an electrical power source. As long as they are spaced apart from each other, the two components are electrically isolated from each other. A short-circuit, that can be detected by means of a monitoring device, occurs only in the case of contact between the two components.
The monitoring device, for example, is integrated in the circuit which, in the case of a short-circuit or contact, connects the two components to each other and indicates that there is current flow or a short-circuit. The monitoring device is designed for detecting the duration of individual short-circuits and to sum them up so as to form a total duration of all short-circuits per time unit. Accordingly, the monitoring device is able to add up the duration of the individual short-circuits per time unit and therefore to determine a total value of the short-circuits or contacts within this time unit. This total duration of all short-circuits is independent of the number of contacts, i.e., how often contacts per time unit have taken place. The only decisive factor is how long in total a contact per this time unit has taken place or, in other words, how long no contact per time unit has taken place. Thus, in the first extreme case, it can occur that this total duration has the value zero, i.e., the gap between the rotating component and the other component is large enough so that they do not touch each other. In the other case, if the total duration of the contact is equal to the time unit itself, a continuous contact or a continuous short-circuit takes place. This indicates that a contact takes place constantly somewhere between the components that face each other. The cause of this, compared to the prior art, can either be a very high number of individual contacts or only a single contact which is simply continuously present during the entire time unit.
The number of individual contacts, which is regarded essential in the prior art, is not relevant for the present invention. Decisive here is only how long in total a contacting takes place, irrespective of whether this contact duration results from a high number of individual contacts or only from a single contact. If the duration of a short-circuit or contact(s) is too long, according to the present invention, a suitable measure for improving the quality of the mode of operation of the textile machine is initiated. Thus, this is a substantial difference between the present invention and the prior art.
In an advantageous textile machine, the further component is a stationary component, a rotating component or, alternatively, a component that moves along the surface of the rotating first component. Thus, the further component can be, for example, a guide plate as a stationary component, or it can be a rotating clothed doffer roller. Likewise, it is possible that the further component is a flat bar that is guided along the surface of the card cylinder and moves accordingly. In principle, any component that is located opposite to the rotating component, in particular to the card cylinder, and that is to be arranged at a close spacing from the rotating component, can be this further component. Suitable spacing between the two components can be determined by the monitoring device.
Preferably, a rotational-speed sensor, e.g., a pulse generator or angular position sensor, is associated with the rotating component. This rotational-speed sensor is able to provide a time unit which relates to the revolution of the rotating component, in particular of the card cylinder. The suitable time unit in this case is, for example, one revolution of the card cylinder so that, for example, unevenness on the card cylinder can be detected in a very simple manner. Alternatively, a fraction of this revolution or a multiple of this revolution can also be used as a suitable time unit.
In a further advantageous embodiment, a device for detecting the revolutions or the position of the rotating component by means of pattern recognition can also be associated with the textile machine. Here, the pattern of the contacts or short-circuits, which do not change or change only insignificantly from one revolution to the next one, is detected and evaluated for the recognition of individual revolutions.
In a further embodiment of the present invention, it is advantageously provided that the textile machine comprises a rotating component and/or the further component which, along an axis of the rotating component, i.e., transverse to the circumferential direction of the rotating component, are/is divided into a plurality of axial sections that are electrically isolated from each other. This makes it possible to detect short-circuits separately in the respective section. In particular sags or contacts that occur only in individual regions or sections can therefore be localized more easily and can be eliminated individually. Thus, for example, in the case of a sag of the further component it is not necessary to change the entire spacing between the rotating component and the further component; rather, it is possible to eliminate the sag, for example, by changing the sag or by locally machining the further component or the rotating component.
In order to be able to evaluate the individual axial sections separately, it is advantageous if a separate power supply and/or a separate monitoring device are/is associated with each axial section. Through this, the section that has generated a short-circuit or a contact can be detected in a very simple manner via the local short-circuits.
Advantageously, a display device for displaying the duration of all short-circuits per time unit is integrated in the textile machine. If, in an advantageous configuration, the textile machine is provided with different axial sections, it can also be advantageous to display in the display device that section in which a short-circuit has taken place. This makes it easier to localize the respective section by a machine controller or by the operator of the textile machine.
In a particularly advantageous embodiment of the textile machine, an automatic adjusting device is provided so as to be able to automatically change the spacing between the rotating component and the further component when a predetermined duration of the short-circuits per time unit is exceeded. This automatic adjusting device can be actuated by an operator of the machine or by the machine controller. Complicated manual adjustments and in particular downtime for the manual adjustments can be avoided in this manner.
Further advantages of the invention are described in the following exemplary embodiments. In the figures:
Reference will now be made to embodiments of the invention, one or more examples of which are shown in the drawings. Each embodiment is provided by way of explanation of the invention, and not as a limitation of the invention. For example features illustrated or described as part of one embodiment can be combined with another embodiment to yield still another embodiment. It is intended that the present invention include these and other modifications and variations to the embodiments described herein.
Similar to the illustration in
According to the exemplary embodiment of the
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The present invention is not limited to the illustrated exemplary embodiments. In particular, it can be applied to different textile machines and to different components of this textile machine.
Modifications and variations can be made to the embodiments illustrated or described herein without departing from the scope and spirit of the invention as set forth in the appended claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 12008343.1 | Dec 2012 | EP | regional |
