EP0816545A1 - Defective weft insertion detection device on a gripper loom - Google Patents

Abstract

An apparatus for detecting a defective weft thread insertion in a rapier loom (1) having a rapier head (2) and thread feeds (7a, 7b, 7c) comprises at least two sensors (5a, 5b). The first sensor (5b) is placed to monitor an introduced weft thread (8c) which runs between an introducing feed (7c) and the rapier head. The second sensor (5a) is placed so that it can detect an undesirably inserted weft thread (8b) running between a thread feed (7a, 7b) located in a stand-by position and the rapier head. Also claimed is a rapier loom having the above apparatus.

Description

The invention relates to a device on a Rapier weaving machine to detect a faulty one Weft thread entry according to the generic term of Claim 1.

Rapier weaving machines are particularly suitable for Production of a fabric comprising a large number different weft threads. The individual weft threads are held by a thread mat and depending on Required presented to a gripper head, which the Grips weft and into the open shed registers. A thread feeder device has Example eight, sixteen, or thirty-two threads on which each carry a weft. Through this Density of weft threads happens that a weft thread to be entered is adjacent to one arranged weft thread and this traveling, so that two or more at the same time Weft threads are entered in the shed. A such incorrect entry is also favored by that qualitatively with a rapier weaving machine different yarns can be woven into one fabric. So the fabric can be a thick, fibrous woolen yarn at the same time have a fine, smooth filament yarn.

It is the object of the present invention for a Rapier weaving machine an economically advantageous Device for detecting a faulty one Propose weft entry.

This task is solved according to the characteristics of Claim 1. Relate to dependent claims 2 to 8 refer to further advantageous embodiments of the Invention.

The invention is achieved in particular by a Device on a rapier weaving machine for recognition an incorrect weft entry, which at least comprises two sensors for detecting a weft thread, sensors being arranged such that the first Sensor a weft thread that is between the submitted thread feeder and the hook head runs, monitors, and that the second sensor is arranged in this way is that an undesirably registered Weft thread that is essentially in between a basic position and the Gripper head runs, detectable by the second sensor is.

To detect the weft threads themselves known sensors use which the weft for example by means of an optical or piezoelectric, electrostatic or magnetic Detect measuring principles.

One advantage of the device according to the invention is that to see that with only two sensors a faulty one Weft thread entry recognizable on a rapier weaving machine is, the rapier weaving machine for any Number of different weft threads can be designed. This device requires few components in particular also a few downstream of the sensors electronic evaluation devices, what a enables cost-effective execution. Furthermore, the two sensor elements with the course of the weft threads no or only small thread deflection angles to design, so that an optimal thread running geometry is achievable.

Fig. 1a

eine schematische Ansicht eines fehlerfreien Schussfadeneintrages einer Greiferwebmaschine;

Fig. 1b

eine schematische Ansicht eines fehlerbehafteten Schussfadeneintrages einer Greiferwebmaschine;

Fig. 1c

eine schematische Ansicht eines fehlerfreien Schussfadeneintrages mit zwei gleichzeitig eingetragenen Schussfäden;

Fig. 2

eine perspektivische Ansicht der erfindungsgemässen Vorrichtung angeordnet in einer Greiferwebmaschine;

Fig. 3

eine perspektivische Ansicht einer weiteren Ausgestaltung der erfindungsgemässen Vorrichtung, angeordnet in einer Greiferwebmaschine;

Fig. 4a

eine Ansicht eines optischen Sensors;

Fig. 4b

eine Ansicht eines kapazitiven Sensors;

Fig. 4c

eine Ansicht einer piezoelektrischen Sensors;

Fig. 5

eine Ansicht eines zur Messung eines Druckes ausgelegten Sensors;

Fig. 6a,6b

perspektivische Ansichten weiterer Ausgestaltungen der erfindungsgemässen Vorrichtung, angeordnet in einer Greiferwebmaschine.

The invention is described in detail with the following exemplary embodiments. Show it:

Fig. 1a

a schematic view of an error-free weft thread entry of a rapier weaving machine;

Fig. 1b

a schematic view of a faulty weft thread entry of a rapier weaving machine;

Fig. 1c

a schematic view of an error-free weft thread entry with two weft threads inserted simultaneously;

Fig. 2

a perspective view of the device according to the invention arranged in a rapier weaving machine;

Fig. 3

a perspective view of a further embodiment of the device according to the invention, arranged in a rapier weaving machine;

Fig. 4a

a view of an optical sensor;

Fig. 4b

a view of a capacitive sensor;

Fig. 4c

a view of a piezoelectric sensor;

Fig. 5

a view of a sensor designed for measuring a pressure;

6a, 6b

Perspective views of further refinements of the device according to the invention, arranged in a rapier weaving machine.

1a shows a schematic view of a Rapier weaving machine 1, which uses a weft thread 8c a gripper 2 in the entry direction 3 in a shed registers. A rapier weaving machine 1 has a plurality of thread feeders 7a, 7b, 7c, each one Lead weft 8a, 8b, 8c, and one each Present the weft 8c to the looper 2. In the shown view is the thread feeder 7c in Direction of movement 9 lowered so that it is in a thread position 7c present position presents the weft 8c to the rapier head 2, which Gripper head 2 detects the weft 8c and in Entry direction 3 conveyed through the shed. The remaining weft threads 8a, 8b are at one end of held a thread clamp 6, and run straight between the thread clamp 6 and the eyelets of the thread feeder 7a, 7b. The warp threads 4a, 4b are also shown, the warp thread 4a being the outermost warp thread and is also referred to as a product edge 4a. Between the Thread feeder 7c and the goods edge 4a is a first Sensor 5b and a second sensor 5a arranged, such that the weft thread 8c which is between the Thread feeder 7c and the hook head 2a runs, comes to lie directly in front of the sensor element 5b, so that the sensor element 5b the presence of the Can detect weft 8c. The two sensors 5a, 5b are in a common sensor housing arranged one above the other.

Fig. 1b shows an incorrect weft insertion. A Rapier weaving machine 1 allows weft threads 8a, 8b, 8c different thread quality and thread type to be entered. In particular, it can happen that adjacent weft threads due to e.g. protruding fibers or very light weight together impose. The one moving in the entry direction 3 Gripper head 2 grips the outside of the shed weft thread 8c. Another, unintentionally carried weft 8b is either gripped by the weft 8c or directly by the hook 2 and also entered in the open shed. This unintentionally carried weft 8b causes a web error, which is why this condition is considered an incorrect entry must be recognized. In the present The exemplary embodiment is the weft thread 8c to be entered submitted by the thread feeder 7c and runs between the Thread feeder 7c and the hook head 2. In this position the weft 8c is detected by the sensor 5b. Of the unintentionally carried weft 8b runs between the one in a basic position Thread feeder 7b and the hook head 2 in one stretched alignment. The sensor 5a is like this ordered that the unintentionally taken away Weft 8b runs directly in front of sensor 5a, see above that the unintentionally carried weft 8b from Sensor 5a is detectable. Another, yourself in one The basic position of the thread feeder 7a is shown, the weft 8a between the Thread feeder 7a and the thread clamp 6 runs. A rapier weaving machine usually has a large number from e.g. 2, 4, 8, 16 or even 32 individual thread feeders 7a, 7b, 7c. The sensor element 5a is such arranged that an accidentally taken away Weft 8b, which is always in between essentially in a basic position Thread feeder 7a, 7b and the hook head 2 runs, is detectable. The sensor 5a is arranged in such a way that each of the weft threads 8b, which is between one of the for Example 32 is in the home position Thread feeders 7a, 7b, 7c and the hook head 2 run should be detectable. So one is enough Sensor 5a around all weft threads 8a, 8b, 8c with respect to one unintentionally carried weft 8b monitor.

1c shows the intended, simultaneous entry of two weft threads 8b, 8c. It can be targeted with one two or more weft threads are woven, by a gripper 2 simultaneously two weft threads 8b, 8c are presented by thread feeders 7b, 7c, which both from the same gripper 2 in the open shed be entered. Even with this weaving process an unintentionally carried weft 8a detect easily by the sensor 5a.

Fig. 2 shows a perspective view of the already in 1a and 1b, according to the invention Contraption. Fig. 2 shows an open shed with Warp threads 4a and the fabric 10. The Weft thread 8a is presented by thread feeder 7c, and is through the hook head 2 and the thread clamp 6th held. The one moving in the entry direction 3 The gripper head 2 becomes the thread end of the weft thread 8a the thread clamp 6 pull and the weft 8a in the Enter the opened shed. The runs Weft 8a in front of the sensor 5b. The electrical signal of the sensor 5b, 5a is electrical Connecting means 5c, 5d, not shown supplied electronic signal evaluation device. Of the Thread feeder 7b is in the basic position and the weft 8b usually runs in a straight line between the thread feeder 7b and the thread clamp 6, such as this is represented by the weft 8d. In the In the present illustration, however, the weft 8b remained hang on the weft 8a, so that the through the Thread feeder 7c also weft 8a Pulls weft 8b into a lower position, causing the Weft thread 8b unintentionally caught by the hook head 2 and is taken away. The weft 8b runs between the one in a basic position Thread feeder 7b, the hook head 2 and the thread clamp 6. During the movement of the gripper head 2 in Entry direction 3 is also unintentional Carried weft 8b captured by the rapier head 3, loosened from the thread clamp 6 and from the hook head 3 into the open shed entered. The sensor 5a is like this arranged that the straight line between the in Basic position of the thread feeder 7b and the Gripper head 2 running weft 8b immediately before runs past the sensor 5a and is detected by it can be so that the unintentionally taken away Weft 8b through the downstream electronic Circuit can be detected. A corresponding one The error signal is generated and the rapier weaving machine 1 transmitted to interrupt the weft entry. During a faultless weft insertion the weft 8d between itself in the basic position located thread feeder 7b and the thread clamp 6 such that the weft 8d is straight, and does not come to rest in front of the sensor 5a. The sensor 5a will therefore not detect any existing weft thread, which means that the weft thread entry is error-free, i.e. without an unintentionally taken weft 8b expires.

2 is outside the open shed a thread guide 35 is arranged, which among other things serves an unintentional purpose to deflect the weft thread 8b, so that It is ensured that the weft 8b in the sensor 5a detectable area passes. Without one Thread guide element 35 there is a risk that the Weft 8b with the rapier inserted deep in the shed 2 comes to lie above the sensor 5a and thus from Sensor 5a can no longer be detected.

Fig. 3 shows a perspective view of another Design of the device according to the invention. in the The two are different from the device according to FIG. 2 Sensors 5a, 5b arranged separately from each other, wherein the sensors 5a, 5b via electrical connection means 5c, 5d with an evaluation device, not shown are connected. The one sensor 5b is again such arranged that one between which is in a submitted position located thread feeder 7c and the weft thread 8a running through the gripper head 2 Sensor 5b is detectable. The second sensor 5a is arranged in such a way that a between the in the Basic position of the thread feeder 7b and Thread clamp 6 running weft 8d such that the weft thread runs at a distance from the sensor 5a 8d can no longer be detected by sensor 5a. The sensor 5a is however arranged such that an unintentional entrained weft 8b, which between the in the basic position thread feeder 7b and Gripper runs, can be detected by sensor 5a. The Presence of an accidentally taken away Weft 8b is about the electrical Connection means 5c, 5d of a downstream Evaluation device transmits which one corresponding trigger signal for the grab machine generated. Next is a thread scissors at the fabric edge 4a 11 for cutting the weft threads 8a, 8b, 8d.

4a shows a view of an optical sensor for Detecting a weft 8c. It is in one Housing 20 with partition 21 and a light emitting diode 22 a phototransistor 23 in the opposite chamber arranged. Those emitted by the LED 22 Rays emerge from the housing 20 through a window 24 are reflected by the weft 8c and kick through the window 24 back into the housing 20 where they are detected by the photo transistor 23. Is not a Weft 8c is present, so there is no reflection instead, so that with a photo transistor 23 downstream evaluation electronics clearly It can be determined whether a weft thread 8c is present or not.

4b shows a view of a capacitive sensor, which is arranged in a housing 20. The sensor has guide elements 33, an insulator 28, and in Center an electrostatic sensor 29, which over an electrically conductive cable 27 with a electronic evaluation device is connected. A electrostatically acting sensor 29 is able to uniquely detect a weft 8c. Of the Weft 8c can rest on the housing, such as shown in which the thread 8c on the two Thread guides 33 rests. The weft 8c can also be spaced from the housing and its presence be detected electrostatically.

4c shows an embodiment of a piezoelectric sensor, which is in a housing 20 is arranged. Inside the sensor is a piezoelectric element 25 arranged, which in one Bearing body 26 and the housing 20 is mounted. At the Housing 20 are arranged thread guides 33. The piezoelectric element 25 also has one Thread guide 33. One on the thread guide 33 adjacent weft 8c exerts a force on the piezoelectric element 25 which generates a signal the one about the electric cable 27 is not shown electronic evaluation device is fed.

5 shows a sensor 111 shown in section. The weft thread 8c runs over the guide elements 103 and via the middle button 113. Within the Housing 102 is arranged the signal converter, which a flexible plate 105 with measuring circuit 109 includes. The flexible plate 105 is such in a body 106 made of elastic material, that the sensing element 113 on the flexible plate 105 works and bends it. The measuring circuit 109 is as a bridge circuit consisting of Resistive elements designed, the electrical Signals over signal lines 118 and one Plug device 119 is guided to the outside. Since it is the sensor 111 is a force sensor Weft 8c always one against the feeler element exert effective force so that the weft 8c can be monitored. With the sensor shown in Figure 5 111 different states of a Detect weft 8c. First, it can be found whether a weft 8c is present. Can continue be determined whether the weft 8c is stationary or moves by the measurement signal after higher-frequency components is examined. Will the Moving weft 8c in the pull-off direction, this causes a slightly vibrating movement of the feeler element 113, what a corresponding alternating signal in the measurement signal generated. It can also be determined whether one or more Weft threads 8c rest on the feeler element 113 by the total force exerted on the feeler element 113 is measured becomes. If there are two otherwise identical weft threads 8c the sensing element 113, the measured one doubles Force. Since the weft 8c has a defined deflection the sensing element 113 and around the guide elements the thread tension in the Weft 8c can be calculated.

Fig. 6a shows a rapier weaving machine with two as in Fig. 5 described force sensors. One by the Thread feeder 7c held in a presented position Weft thread 8c is made in the direction of entry 3 moving gripper 2 entered in the shed. Here is the sensor 111b between eyelet 36 and submitted thread feeder 7c arranged that the Weft 8c over the feeler 113 and the Guide elements 103 runs. In this position famous the weft 8c does not have the second sensor 111a. Of the second sensor 111a is between a hook 35 and the one in a basic position, dashed illustrated thread feeder 7c arranged that the Weft 8c (shown in dashed lines) only over the second sensor 111a runs. The sensors 111a, 111b are such with respect to the weft 8a, 8b, 8c arranged that the previously on the basis of the weft 8c explained arrangement applies to each of the weft threads. Consequently each runs from a thread feeder 7b, 7c Weft 8b, 8c via sensor 111b, respectively each of thread feeder 7b, 7c in a basic position held weft thread 8b, 8c runs over the sensor 111a. Would in the embodiment of FIG. 6a Weft 8b accidentally torn away, so the Run weft 8b over sensor 111a and from this can be detected. 6b is another Possibility of arranging two sensors 111a, 111b shown which sensors according to the in Fig. 5th shown principle are built. Both are there Sensors 111a, 111b between the hook 35 and the Thread feeder 7b, 7c arranged, corresponding to the two end positions of the thread feeder 7b, 7c Weft 8c either via one sensor 111b or the other sensor 111a runs. An advantage of one 6a, 6b can be seen in that the Thread tension throughout the weft insertion is measurable. Another advantage of this arrangement is to be seen in the fact that the sensor 111a, 111b at any time a zero point calibration can be carried out. At the 5 is a force sensor with a bridge circuit made up of resistance elements. This bridge circuit also allows low forces Measuring accurately, however, has the disadvantage of one Zero drift so that the sensor is always new must be calibrated by placing the sensor in a defined state is brought. This can be done with 6a, 6b in a simple manner thereby achieve that the thread feeder 7b, 7c be operated that not a single weft 8b, 8c touches the sensor 111a, 111b. Thus, one can arbitrarily selectable point in time and repeats the Sensor 111a, 111b are re-calibrated. Not shown is a signal evaluation device which a Has zero-point calibration device, on the one hand the Thread feeder 7b, 7c actuated such that no Weft 8c rests on the sensor 111a, 111b, and on the other hand, the calibration process on the sensor 111a, 111b and saves the new zero point values and at the following measurements are taken into account.

Claims (9)

Device on a rapier weaving machine (1) for Detection of an incorrect weft thread entry, the rapier weaving machine (1) having a rapier head (2) and thread feeder (7a, 7b, 7c), thereby characterized in that the device has at least two Sensors (5a, 5b) for detecting a weft thread (8a, 8b, 8c) comprises which sensors (5a, 5b) in this way are arranged that the first sensor (5b) one submitted weft (8c) between the submitted thread feeder (7c) and the hook head (2) runs, monitors, and that the second sensor (5a) is arranged such that a unwanted weft thread (8b), that between one essentially in one Basic position of the thread feeder (7a, 7b) and the gripper head (2) runs from the second sensor (5a) is detectable. Device according to claim 1, characterized in that the first sensor (5b) is arranged and is designed that several weft threads (8a, 8b, 8c) simultaneously from the first sensor (5b) are detectable. Device according to one of claims 1 or 2, characterized in that the first and the second Sensor (5a, 5b) is arranged one above the other. Device according to one of claims 1 or 2, characterized in that the first and second Sensor (5a, 5b) designed as separate units are. Device according to one of claims 1 to 4, characterized characterized in that the sensors (5a, 5b) on a optical, piezoelectric, electrostatic or based on the magnetic measuring principle. Device according to one of claims 1 to 4, characterized characterized in that the sensors (5a, 5b) for Measurement of a pressure or one Thread tension are formed, and that the sensors (5a, 5b) are arranged such that one of the Looper head (2) gripped weft thread (8a, 8b, 8c) the sensor (5a, 5b) during the weft insertion at least temporarily touched. Apparatus according to claim 6, characterized in that the sensor (5a, 5b) is arranged such that a weft thread (8a, 8b, 8c) by actuation of the thread feeder (7a, 7b, 7c) from the sensor (5a, 5b) is removable in order to control the sensor (5a, 5b) to bring an unloaded state. Device according to claim 7, characterized in that the sensor (5a, 5b) with a Signal evaluation device, comprising a Zero calibration device, is connected, and that the thread feeder (7a, 7b, 7c) and Coordinated zero calibration device in this way can be controlled that when the sensor is not loaded (5a, 5b) a zero point calibration can be carried out. Rapier weaving machine with a device according to a of claims 1 to 8.

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