EP0276206B1 - Contact bar for electric stop motion - Google Patents

Abstract

One of the rails in a contact rail, suitably the inner rail (12) is provided over its length with a linearly increasing electric resistance that can be acquired as a measurable value at any point along the rail. A preferred embodiment has for this purpose a metallic conductor (11) helically wound around an isolating body (10). This inner rail (12) is held in an outer rail (13) with an upper U-shaped cross-section, and is separated therefrom by an isolating layer (14). The helically wound metallic conductor (11) has a considerably higher resistance compared to a massive rail, suitable for applying a measurement method based on the measuring bridge principle for locating a drop wire that has fallen on the contact rail in case of thread breakage. The distance between the fallen drop wire and one end of the rail can be determined from the relationship between the resistance of the whole inner rail (12) and the resistance of the section of inner rail extending from one end of the rail to the fallen drop wire, this resistance relationship being determined by the electric measuring bridge.

Description

The invention relates to a contact rail for an electrical thread monitor of a textile machine, with two mutually parallel and mutually insulated, electrically conductive rails, which together extend through the slots of a plurality of monitor slats arranged on the threads and through one with thread breakage with the two rails in Contact coming guard slat to be electrically conductive to trigger a machine stop.

If warp threads are monitored in this way, this device is called a warp thread monitor. In known electrical warp thread monitors with a plurality of contact rails each consisting of an outer rail and an inner rail, the upper edge of the inner rail is serrated by forming rectangular punched-out sections, so that a guard lamella falling in the event of a broken warp thread is caught in a punched-out section and by a back and forth movement of the contact rail or only the inner rail is taken along by means of a lever provided for this on the warp thread monitor, so that when the monitor slat is laterally displaced in this way, an alley is formed between the other monitor slats, which makes it easier to find the broken warp thread.

In the course of technical development, ever wider weaving machines are built and the associated warp thread monitors therefore have contact rails of several meters in length, of which a plurality are arranged in parallel in a warp thread monitor and on which many hundreds of guard slats are lined up and carried by the warp threads. With increasing weaving width, it is therefore becoming increasingly difficult and time-consuming for the operating personnel to find the guard slat that has fallen onto the contact rail as a result of the thread breakage among the many hundreds of guard slats. In the known thread monitors, this is done, as already mentioned, by longitudinally displacing the contact rails and thereby forming a small lane, the presence of which can be determined by searching on any of the plurality of contact rails.

The object underlying the present invention was to design a contact rail for a thread monitor in such a way that it is possible to localize a thread break without having to search for the long contact rails after the fallen guard slat and with considerably less time, which reduces the downtimes of the machine and productivity is increased. Furthermore, it is also the solution to the task of monitoring weaving machines with regard to thread breaks by registering the frequency and local distribution of thread breaks, storing them as data and evaluating them centrally for a wide variety of purposes.

A fairly precise localization of the broken thread or the fallen guard lamella can be carried out electrically by determining the distance between the guard lamella falling on the contact rail and one of the two ends of the contact rail. It is known that a line break or short circuit can be located in an electrical conductor pair according to the principle of the electrical measuring bridge. However, a solid rail, as in the present case the inner rail of the contact rail, is of course unsuitable for tapping resistors for the purpose of using the principle of the electrical measuring bridge. For the inner rail coming into contact with the guard slats, an electrical conductor is required which has a resistance which is substantially higher than that of the usual rails and which has a linearly increasing resistance curve over the length of the rail. A thin wire that fulfills this condition is, however, completely unsuitable as an electrical conductor in the function of the inner rail of the contact rail used in a thread monitor, because a wire that is sufficiently high and suitable for the measurement method and is correspondingly thin is suitable for the rough operation in a weaving mill and the like Would not withstand stress from the guard slats.

In the event of a thread break, the fallen guard slat comes into contact with the inner rail and the outer rail of the contact rail in order to trigger a machine stop. The inner rail as well as the outer rail are therefore suitable for carrying out the aforementioned method according to the principle of the electrical measuring bridge. To achieve the above object, the contact rail of the type mentioned has the features according to claim 1. A rail with these properties, which make it possible to tap a resistance as a measurable value at any point along the rail, can be designed in very different ways.

An electrical conductor applied to an insulating material body can be a band-shaped material applied in a special form to the insulating material body, which is applied, for example, as a coil, but it can also have a different configuration, such as a meandering shape, or the electrical conductor can be in the form of a Coating can be applied to an insulating material body, for example it can be vapor-deposited or applied galvanically or plated, etc. All of the exemplary embodiments involve bringing an electrical conductor with an electrical resistance that is substantially higher than that of a conventional rail into a rail shape with sufficient robustness and stability with regard to the mechanical stress.

Appropriately used for the present here Purpose as the simplest design solution, the inner rail of the contact rail, which is held in the known thread monitors in a cross-sectionally U-shaped outer rail and which itself has a rectangular cross-section, so that an electrical conductor is expediently applied to a cross-section-shaped insulating material body. In an expedient embodiment, this consists of a metal conductor helix which is wound tightly but without touching the turns on the insulating material body.

• Fig. 1 eine Kontaktschiene mit darauf angeordneter Wächterlamelle in schaubildlicher Darstellung;
• Fig. 2 einen Querschnitt durch eine Kontaktschiene gemäss Fig. 1 in grösserem Maßstab;
• Fig. 3 ausschnittweise in Seitenansicht eine Kontaktschiene mit Metalleiterwendel auf der Innenschiene;
• Fig. 4 einen Querschnitt durch die Kontaktschiene gemäss Fig. 3;
• Fig. 5 die Innenschiene in grösserem Maßstab, mit einer Beschichtung als elektrischer Leiter;
• Fig. 6 die Innenschiene mit zwei streifenförmigen elektrischen Leitern;
• Fig. 7 die Innenschiene mit einem gitterförmigen Geflecht als elektrischer Leiter;
• Fig. 8, 9 und 10 Querschnitt, Seitenansicht und Draufsicht der Innenschiene mit einer dünnen Leiterbahn und dickeren Kontaktkörpern am Schienenoberrand;
• Fig. 11 - 14, Querschnitt, Seitenansicht, Draufsicht und Abwicklung der Aussenseiten einer Innenschiene mit einem elektrischen Leiter in Mäanderform;
• Fig. 15 eine Kontaktschiene in Seitenansicht mit Wächterlamellen und die schematische Darstellung des Prinzips zum Auffinden einer gefallenen Wächterlamelle.

The invention is explained in more detail below on the basis of exemplary embodiments illustrated in the drawings. Show it:

• 1 shows a contact rail with a guard plate arranged thereon in a diagrammatic representation;
• FIG. 2 shows a cross section through a contact rail according to FIG. 1 on a larger scale;
• 3 shows a detail in side view of a contact rail with a metal conductor helix on the inner rail;
• FIG. 4 shows a cross section through the contact rail according to FIG. 3;
• Figure 5 shows the inner rail on a larger scale, with a coating as an electrical conductor.
• 6 shows the inner rail with two strip-shaped electrical conductors;
• 7 shows the inner rail with a grid-shaped braid as an electrical conductor;
• Figures 8, 9 and 10 cross-section, side view and top view of the inner rail with a thin conductor track and thicker contact bodies on the upper edge of the rail.
• 11 - 14, cross section, side view, top view and development of the outer sides of an inner rail with an electrical conductor in a meandering shape;
• Fig. 15 is a side view of a contact rail with guard slats and the schematic representation of the principle for finding a fallen guard slat.

In Fig. 1, a contact rail 1 is also used in known thread monitors, which extends through the slot 2 of a monitor plate 3 and is shown broken off there. A thread 5, for example a warp thread, extends through the thread eye 4 of the guard plate 3, and in the event of a thread break, the guard plate 3 falls onto the contact rail 1.

The contact rail 1 consists of an outer rail 6 with a groove 7 on the upper edge, in which the inner rail 9 is held separately by an insulating material layer 8. The cross section according to FIG. 2 on a larger scale shows the structure more clearly. The outer rail 6 and the inner rail 9 are live and are electrically connected by a falling guard lamella 3, so that a machine stop is triggered if the thread breaks. The functional principle of the contact rail according to FIGS. 1 and 2 applies to all embodiments according to the invention according to FIGS. 3-15. Details that cannot be seen in FIGS. 1 and 2 relate to the different embodiments of the inner rail. In the embodiment according to FIGS. 3 and 4, a metal conductor helix 11 is wound onto an insulating material body 10 which has a cuboid cross-section in such a way that the turns do not touch while maintaining a very small distance. The metal coil 11 is formed by winding a strip material, which is preferably made of chromium-nickel steel and has a cross section that is constant over the length. The strip material itself is considerably longer than an inner rail 12 created by the winding of the strip material on the insulating material body 10. An inner rail designed in this way now has a much higher electrical resistance, for example between 20 and 100 ohms, than a solid rail having the same length the electrical resistance is almost zero. The inner rail 12, which is flat overall in cross section, consists of the insulating material body 10 and the metal conductor helix 11 and is held in the outer rail 13 which is U-shaped in cross section in the upper part, an insulating material layer 14 being arranged between the inner rail 12 and the outer rail 13.

The distance between the turns of the metal conductor helix 11 is smaller than the material thickness of the guard lamella 3, so that it is ensured that a guard lamella 3 which has fallen when the thread breaks always makes electrical contact between the metal conductor helix 11 and the outer rail 13. The inner rail 12 having the metal conductor helix 11 and the outer rail 13 are known to form conductors in an electrical circuit, which is closed by the guard lamella 3 which establishes an electrical connection between the inner rail 12 and the outer rail 13, as a result of which the loom is stopped.

5, a modified embodiment of the inner rail 15 consists of an insulating material body 16 and an electrically conductive coating 17 applied to this body, which is very thin in order to achieve a high resistance value suitable for the measurement method mentioned and is, for example, vapor-deposited or galvanically applied. A coating can also be rolled on or plated on. It does not have to cover the entire surface.

An inner rail 19 shown in FIG. 6 consists of an insulating material body 20, on the oblique surfaces 21 extending on the upper longitudinal edge, narrow electrical conductors 22 are applied, which extend over the entire length of the rail and come into contact with a fallen guard lamella 3.

An inner rail 23 shown in FIG. 7 consists of an insulating material body 24 and a grid-shaped braid 25 applied to this body and formed from electrical conductors.

In a further embodiment according to FIGS. 8-10, an inner rail 26 consists of a flat insulating material body 27, which on one of its two longitudinal sides, which does not come into contact with a fallen guard slat 3, has a thin conductor track 28 which extends over the rail length and which is located at a point protected against mechanical stress and has the electrical resistance suitable for the measuring method and can be tapped at any point along the rail as a measurable value. This electrical conductor track 28 is connected to contact bodies 29 arranged on the upper longitudinal edge of the insulating material body 27 in a tight row one behind the other but at a small distance from one another, in each case via an electrical conductor 30, these contact bodies 29 having a greater material thickness and encompassing the upper edge of the insulating material body Resist occurring mechanical stress, so that the conductor track 28 used for the measurement method can be made very thin. The contact bodies 29 are delimited by inclined surfaces similar to the helical helix, so that contact with a guard plate is always ensured. This can be seen from the side view of the rail 26 according to FIG. 9 and the top view according to FIG. 10.

A further embodiment of an inner rail 33 shown in FIGS. 11-14 consists of an insulating material body 34, on which an electrical conductor track 35 with a constant cross section and with a linear course in the longitudinal and transverse direction of the rail is applied. A course of the conductor track that is linear in the longitudinal and transverse direction of the rail is also present in the metal conductor helix 11 according to FIG. 3. Such a course of the conductor track is also present in the embodiment of the rail 33 according to FIGS. 11-14 when the conductor track is designed in a meandering shape. The objective is always the same, namely to accommodate a large length of the conductor track on a certain length of rail. The electrical conductor track in a meandering shape extends around the insulating material body 34 with the exception of the lower side surface, as can also be seen from the side view according to FIG. 12. A development of the rail surface with the conductor track is shown in FIG. 14, in which it can also be seen that the conductor track in each case runs obliquely at the upper edge of the rail that comes into contact with the guard plate, which is also apparent from the top view of the rail according to FIG. 13 , and for the reason already mentioned, to ensure contact with a guard slat at any point along the rail.

15 schematically shows the principle of the method which can be carried out using a contact rail according to the invention for locating a guard slat which has fallen onto the contact rail in the event of a thread break. The contact rail 1 has one of the embodiments shown in FIGS. 3-14. There are also shown a number of guard slats 3, which are actually lined up very close to one another on the contact rail, the contact bar 1 extending through the slots 2 of the guard slats 3, as is also shown in FIG. 1. A warp thread 5 extends through the thread eye 4 of each guard slat 3, on each of which a guard slat hangs. A guard slat shown in the middle in FIG. 15 has fallen onto the contact rail 1 as a result of thread breakage. This fallen guard slat is to be located on a contact rail several meters long with a very large number of guard slats. Since the inner rail of the contact rail has, as described above, an electrical resistance that increases linearly over its length and can be tapped at any point along the rail as a measurable value, a resistance ratio between the resistance of the one that extends over the entire rail length can be measured according to the principle of the electrical measuring bridge Determine the electrical conductor of the inner rail and the resistance of the partial length of this electrical conductor from one end of the rail to the fallen guard slat. 15, the total rail length 1 has a resistance R, and the partial length 1 has a resistance Ri. The principle of the electrical measuring bridge used for determining the resistance ratio is known. In the diagram according to FIG. 15, a bridge feed 40 is electrically connected to the inner rail of the contact rail 1. 41 is a "sample and hold" amplifier, 43 is an amplifier, 44 is an A / D converter and 45 the display device. This shows a digital display, whereby a value can be read as a length dimension for the distance 1 between the rail end and the fallen guard slat. To supplement this, you only need, for example, a measuring stick attached to the thread monitor or a measuring tape that can be rolled up to search for the distance value read on the display device and thus find the fallen detector slat and the thread break point.

The weaving machine is stopped by a falling guard slat. A relay 46 arranged behind the amplifier 43 actuates the switch 47 to stop the loom.

The digitized data already available for the display can be forwarded by the A / D converter 44 to a data processing system via a serial interface 48. There, for example, the data of a group of weaving machines with warp thread monitoring devices are collected in order to evaluate them with regard to the frequency of thread breaks, where these occur, etc. The advantages resulting from these possibilities in terms of work technology and economics are just as important as the quick detection of a thread break.

Claims (14)

1. A contact bar for an electric stop motion of a textile machine, two electrically conductive bars being provided which are parallel to and insulated from one another, extend together through the slots of a large number of stop motion lamellae disposed on the yarns and are electrically interconnected to stop the machine by a stop motion lamella which contacts both bars in the event of a yarn breakage, characterised in that one of the bars has an electrical conductor which is made of a homogeneous material and which is disposed on an insulating member and which has an electrical resistance increasing linearly along bar length and adapted to be tapped anywhere along the bar as a measurable value.

2. A contact bar according to claim 1, characterised in that an electrical conductor path (11, 35) of constant cross-section and of considerably greater length than bar length and having a linear extent which is continuous lengthwise and transversely of the bar is disposed on an insulating member (10, 34).

3. A contact bar according to claim 2, characterised in that the conductor path disposed on an insulating member (10) with a continuous linear extent lengthwise and transversely of the bar.

4. A contact bar according to claim 2, characterised in that the said conductor path disposed on an insulating member (34) has a meandering shape (35).

5. A contact bar according to claim 2 or, characterised in that the inner bar (12, 15, 19, 23, 26, 33) has the electrical conductor (11, 17, 22, 25, 28, 29, 35) which is disposed on an insulating member (10, 16, 20, 24, 27, 34).

6. A contact bar according to claims 3 and 5, characterised in that the inner bar (12) is in the form of a flat insulating member (10) and of a metallic conductor helix (11) of constant cross-section which is disposed on the member (10), the helix turns not contacting one another.

7. A contact bar according to claim 6, characterised in that the helix (11) is made of strip material.

8. A contact bar according to claim 7, characterised in that the strip material of the helix (11) is nickel chromium steel.

9. A contact bar according to claim 6, characterised in that the flat metallic conductor helix (11) wound on the insulating member (10) is secured, preferably by gluing, in a groove in a channel- section outer bar (13).

10. A contact bar according to claim 1, characterised in that one of the bars (15) has an electrically conductive coating (17) applied to an insulating member (16), the coating (17) being, for instance, in the form of a vapour-coated or electroplated or rolled-on or platedon coating.

11. A contact bar according to claim 1, characterised in that one of the bars (19) has electrical conductors (22) disposed on an insulating member (20) on diagonal surfaces (21) extending on both sides of the top longitudinal edge of the insulating member (20).

12. A contact bar according to claim 1, characterised in that one of the bars (23) has a lattice- like braiding (25) which is disposed on an insulating member (24) and which is formed by electrical conductors.

13. A contact bar according to claim 1, characterised in that one of the bars (26) has an electrical conductor path (28) which is disposed on an insulating member (27) by way of a long side not contacting the stop motion lamella (3) and which has an electrical resistance adapted to be tapped anywhere along the bar as a measurable value, and said one of the bars (26) has on the top longitudinal edge of the insulating member a large number of contact members (29) which are disposed in spaced end-to-end relationship to one another, have a greater material thickness that the electrical conductor path (28) and are each electrically connected individually to such path (28).

14. Use of the contact bar according to any of claims 1 - 13, characterised in that to locate the position of the stop motion lamella contacting both bars in the event of a yarn breakage the ratio of the resistance of the overall length of the bar to the resistance of the sub length of the bar from one end thereof as far as the lamella in contact with the bars is found and is displayed as a measured distance value.

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