阅读说明：本技术 织机中纱线的定位和连续性的控制 (Control of the positioning and continuity of the yarn in a loom ) 是由 马修·朱利安·查拉斯 于 2020-03-16 设计创作，主要内容包括：一种编织装置(400),其包括织机(100),旨在通过将多根纱线编织在一起来制造编织织物,多根纱线中的至少一些纱线是碳纱线(210、211、212、213、214、215),碳纱线各自单独存储在织机上游存在的多个碳纱线存储线轴(220、221、222、223、224、225)中的一个线轴上。该装置还包括存在于存储线轴(220、221、222、223、224、225)和织机(100)之间的多对第一和第二电触点(301、302；303、304；305、306；307、308；309、310；311、312)。每对第一和第二电触点存在于碳纱线的路径中,每对的第一和第二触点旨在与给定的碳纱线电接触。每对第一和第二触点中的触点也连接到开路检测电路(230)。(A weaving device (400) comprising a weaving machine (100) intended to manufacture a woven fabric by weaving together a plurality of yarns, at least some of which are carbon yarns (210, 211, 212, 213, 214, 215) each stored individually on one of a plurality of carbon yarn storage spools (220, 221, 222, 223, 224, 225) present upstream of the weaving machine. The device further comprises a plurality of pairs of first and second electrical contacts (301, 302; 303, 304; 305, 306; 307, 308; 309, 310; 311, 312) present between the storage spools (220, 221, 222, 223, 224, 225) and the loom (100). Each pair of first and second electrical contacts is present in the path of the carbon yarn, the first and second contacts of each pair being intended to be in electrical contact with a given carbon yarn. The contacts of each pair of first and second contacts are also connected to an open circuit detection circuit (230).)

1. Weaving device (400) comprising a weaving loom (100) for manufacturing a woven fabric by weaving between a plurality of yarns, at least a part of which are carbon yarns (210, 211, 212, 213, 214, 215), the carbon yarns are each individually stored on one of a plurality of carbon yarn storage spools (220, 221, 222, 223, 224, 225) present upstream of the weaving machine, characterized in that it comprises a plurality of pairs of first and second electrical contacts (301, 302; 303, 304; 305, 306; 307, 308; 309, 310; 311, 312) present between the storage spools (220, 221, 222, 223, 252 and 224) and the loom (100), each pair of first and second electrical contacts being present in the path of the carbon yarn, the first and second contacts of each pair are intended to be in electrical contact with a given carbon yarn, the contacts of each pair being further connected to an open circuit detection circuit (230).

2. The apparatus of claim 1, wherein a first electrical contact (301, 303, 305, 307, 309, 311) of the plurality of pairs of first and second electrical contacts is present near a plurality of carbon yarn storage spools (220, 221, 222, 223, 224, 225), and a second electrical contact (302, 304, 306, 308, 310, 312) of the plurality of pairs of first and second electrical contacts is present near an entrance of the loom (100).

3. The device according to claim 1 or 2, wherein each contact of the plurality of pairs of first and second electrical contacts (301, 302; 303, 304; 305, 306; 307, 308; 309, 310; 311, 312) comprises a rotatable conductive element, each conductive element being intended to be in contact with a carbon yarn (210; 211; 212; 213; 214; 215).

4. The apparatus according to any one of claims 1 to 3, further comprising a monitoring system (250) connected to said open circuit detection circuit (230), a control device configured to issue a stop signal or an error signal to the loom (100) in response to the detection of an open circuit between the electrical contacts of at least one pair of first and second electrical contacts.

5. The apparatus of any of claims 1 to 4, wherein the open circuit detection circuit (230) is a low voltage circuit.

6. A method for monitoring the positioning and continuity of carbon yarns in a weaving device (400) according to any one of claims 1 to 5, comprising a weaving machine (100) for manufacturing a woven fabric by weaving between a plurality of yarns, at least some of which are carbon yarns (210, 211, 212, 213, 214, 215) each stored individually on one of a plurality of carbon yarn storage spools (220, 221, 222, 223, 224, 225) present upstream of the weaving machine, characterized in that it comprises monitoring the presence of each carbon yarn between a storage spool and the weaving machine by detecting one or more open circuits.

7. The method of claim 6, wherein monitoring the presence of each carbon yarn comprises connecting each carbon yarn to an open circuit detection circuit (230), the connecting comprising making a first electrical contact on a carbon yarn (210; 211; 212; 213; 214; 215) near a carbon yarn storage spool (220; 221; 222; 223; 224; 225) and making a second electrical contact on the same carbon yarn near an entrance to the loom (100).

8. The method of claim 7, wherein making the first and second electrical contacts is accomplished with first and second rotatable conductive elements, respectively.

9. The method of any of claims 6 to 8, further comprising stopping the loom (100) or issuing an error signal in response to detecting that no carbon yarn is present between the storage spool (220, 221, 222, 223, 224, 225) and the loom (100).

10. The method of any of claims 7 to 9, wherein the open circuit detection circuit (230) is a low voltage circuit.

Technical Field

The present invention relates to the field of looms, in particular to the field of fiber-reinforced looms using carbon fibers for producing composite parts.

Background

The preparation of the warp, also called warping, is a very cumbersome operation, since it involves placing each carbon yarn one by one on a perforated plate to order the yarns for weaving or the yarns in the heddle eyelet and fixing them at the loom outlet using the existing yarn-calling system. This operation is a source of error because the number of carbon yarns to be placed can be very large, for example over one hundred, and the distance between each yarn is very small.

Furthermore, even with proper warp preparation, one or more yarns may break during weaving. It is sometimes difficult to find breaks in the carbon yarns in all warp yarns.

In any case, incorrect yarn placement at the start or yarn breakage during weaving can have significant consequences, since the obtained fiber reinforcement does not have all the required mechanical properties, which can lead to a risk of waste and thus to a waste of raw materials.

Disclosure of Invention

Therefore, a solution is desired to monitor the correct positioning and integrity (continuity) of the carbon yarns in the loom.

To this end, according to the invention, a weaving device is provided comprising a weaving machine for manufacturing a woven fabric by weaving between a plurality of yarns, at least a portion of which are carbon yarns, each carbon yarn being stored individually on one of a plurality of carbon yarn storage spools present upstream of the weaving machine, characterized in that it comprises a plurality of pairs of first and second electrical contacts present between the storage spools and the weaving machine, each pair of first and second electrical contacts being present in the path of a carbon yarn, the first and second contacts of each pair being intended to be in electrical contact with a given carbon yarn, the contacts of each pair being further connected to an open circuit detection circuit.

The weaving device of the invention is able to monitor the preparation of the warp threads in the loom and the integrity of each warp thread during weaving, before weaving, thanks to the presence of a pair of electrical contacts in the path of each thread. In fact, as regards the preparation of the warp threads, if one or more of them are incorrectly positioned, the associated open detection circuit will detect this error, which allows the operator to correctly replace each incorrectly positioned thread before starting the loom. Similarly, if one or more warp threads break during weaving, the associated open circuit detection circuit will detect this condition, allowing immediate intervention.

According to a first particular feature of the weaving device according to the invention, the first and second electrical contacts of each pair are located respectively near the carbon yarn storage bobbin and near the entrance of the weaving loom. This covers the majority of the path of the warp yarn before it enters the loom.

According to a second particular feature of the weaving device according to the invention, each contact of the plurality of pairs of first and second electrical contacts comprises a rotatable conductive element, each conductive element being intended to be in contact with a yarn of the plurality of carbon yarns. Thus, the wear on the yarn as it passes through the electrical contacts is greatly reduced.

According to a third particular feature of the weaving device according to the invention, the weaving device further comprises a monitoring system connected to the open circuit detection circuit, a control device configured to issue a stop signal or an error signal to the weaving machine in response to the detection of an open circuit between the electrical contacts of the at least one pair of first and second electrical contacts. The system thus enables automatic control of the loom in the event of an accident of one or more warp threads.

According to a fourth particular feature of the knitting apparatus of the invention, the open circuit detection circuit is a low voltage circuit. This can prevent arcing from possibly occurring in the device.

The invention also relates to a method for monitoring the positioning and continuity of carbon yarns in a weaving device according to the invention, comprising a weaving machine for manufacturing a woven fabric by weaving between a plurality of yarns, at least one portion of which is a carbon yarn, each carbon yarn being stored separately on one of a plurality of carbon yarn storage spools present upstream of the weaving machine, characterized in that it comprises monitoring the presence of each carbon yarn between the storage spool and the weaving machine by detecting one or more open circuits.

The method of the invention makes it possible to monitor the correct positioning of the warp threads at the end of preparation of the warp threads and to correct any positioning errors before starting the loom, thus ensuring a compliant weaving. Furthermore, the method of the invention allows to detect in real time the breakage of the warp threads during the knitting process, so as to apply corrective measures quickly when necessary.

According to a first particular feature of the weaving method according to the invention, the monitoring of the presence of each carbon yarn comprises connecting each carbon yarn to an open circuit detection circuit, the connection comprising a first electrical contact on the carbon yarn in the vicinity of the carbon yarn storage spool and a second electrical contact on the same carbon yarn in the vicinity of the loom entrance.

According to a second particular feature of the weaving method according to the invention, the engagement of the first and second electrical contacts is carried out with a first and second rotatable conductive element, respectively.

According to a third particular feature of the weaving method according to the invention, the latter further comprises stopping the loom or issuing an error signal in response to detecting the absence of carbon yarn between the storage spool and the loom.

According to a fourth particular feature of the weaving method according to the invention, the open circuit detection circuit is a low voltage circuit.

Drawings

Fig. 1 is a schematic perspective view of a braiding apparatus according to an embodiment of the present invention.

Detailed Description

The invention is generally applied to weaving machines for producing a fibre fabric from carbon fibre yarns, which are stored in a spool upstream of the weaving machine and are unwound to the weaving machine outlet. The invention applies in particular to jacquard-type weaving machines, which are used in particular for producing a fibrous fabric or texture between a layer of warp threads and a layer of weft threads by means of two-dimensional (2D) and three-dimensional (3D) or multi-layer weaving.

Fig. 1 very schematically shows a weaving device 400 according to an embodiment of the invention. The weaving device 300 comprises a weaving machine 100, the warp of which is fed with carbon yarns (including yarns consisting of carbon fibers). For the sake of clarity, fig. 1 shows only 6 carbon warp yarns 210 to 215 each stored on 6 bobbins 220 to 225 respectively. The spools are stored on a rack, also referred to as a spool rack (not shown in fig. 1). Conventionally, the loom 100 comprises, from upstream to downstream, a first crossbar 110, a bar or rod 120 (which may be replaced by one or more carriages), a harness 130, a reed 140, a shuttle or spray gun 150 and a second crossbar or drum 160, intended for taking up warp yarns and winding up the woven fabric. Harness 130 is provided with a heddle 131 with eyelets (not shown) through which warp threads 210 to 215 pass, heddle 131 being moved in an upward or downward direction to create a passage or shed in the axial direction of the path of shuttle 150 intended for the passage of a weft thread 230.

According to the invention, the weaving device 400 also comprises a plurality of pairs of first and second electrical contacts present between the storage spool and the weaving loom, which pairs of contacts form part of the yarn positioning and continuity monitoring system 300. More precisely, in the example described here, the system comprises 6 pairs of first and second electrical contacts 301 and 302, 303 and 04, 305 and 306, 307 and 308, 309 and 310, and 311 and 312, intended to be in electrical contact with the carbon warp threads 210, 211, 212, 213, 214 and 215, respectively. The first electrical contacts 301, 303, 305, 307 and 309 are preferably placed near the bobbins 220 to 225, while the second electrical contacts are preferably placed near the entrance of the loom 100 to cover the path of the majority of the warp yarns before they are woven into the loom. Each pair of electrical contacts is connected to an open circuit detection circuit described in more detail below.

In the present invention, the conductive properties of the carbon fibers constituting the carbon yarn are advantageously utilized. In fact, since carbon fibers are composed of graphite crystal domains (graphitic domains), they have the electrical characteristics of graphite. Graphite is an anisotropic material with very good electrical conductivity in the direction of the graphene plane. Since the graphite domains are oriented in the longitudinal direction of the fiber, the fiber has good thermal and electrical properties in the yarn direction. Thus, if the graphitic properties of the fiber increase, the resistivity of the fiber decreases, ranging from 900 μ Ω. cm for high modulus fibers (350GPa to 500GPa) to 1650 μ Ω. cm for fibers with lower modulus (200GPa to 300 GPa).

Thus, the presence of each warp yarn at the loom entrance can be continuously monitored (i.e. before and during weaving) by means of a pair of electrical contacts present in each yarn path. Each pair of electrical contacts may be static, i.e. they each consist of a fixed element having an electrically conductive surface on which the carbon yarn slides. According to another feature of the invention, each electrical contact may be constituted by a rotatable conductive element which minimizes friction on the carbon yarn and reduces the risk of damaging said yarn. In the example described here, the first and second electrical contacts 301 and 302, 303 and 304, 305 and 306, 307 and 308, 309 and 310, and 311 and 312 of each pair are composed of rollers made of an electrically conductive metal material, such as copper. Thus, the movement of the carbon yarn between its storage spool and the loom causes the two rollers forming the first and second pairs of electrical contacts to rotate, maintaining permanent electrical contact with the carbon yarn without being worn by friction. The roller used here may be of the pulley or wheel type, optionally associated with a spring support, in order to better monitor the electrical contact with the yarn without imposing too much stress thereon.

The yarn positioning and continuity monitoring system 300 includes a plurality of open circuit detection circuits, each connected to a given pair of the first and second electrical contacts.

For clarity, only one open circuit detection circuit 230 is shown in fig. 1, the circuit 230 being connected to first and second electrical contacts 301 and 302 present in the path of the carbon yarn 210. The other five open circuit detection circuits are connected to the first and second pairs of electrical contacts 303 and 304, 305 and 306, 307 and 308, 309 and 310, and 311 and 312, respectively.

The open circuit detection circuit 230 includes a voltage generator 231 in series with a resistor 232. Circuit 230 also includes a voltmeter 233 connected in parallel with resistor 232. The voltage measurements made by voltmeter 233 are transmitted to a monitoring device 250, such as a computer, via analog-to-digital converter 234.

The electrical contacts of each pair of contacts are used to return the open circuit detection circuit. In the event that the carbon yarn does not contact or loses contact with at least one of the pair of electrical contacts, the circuit becomes open and the voltage aux measured by the voltmeter is zero.

The monitoring means 250 includes a dedicated input for each voltage measurement signal provided by the identified open circuit detection circuit to enable a determination of which carbon yarn is broken or incorrectly placed when an open circuit is detected.

The open circuit detection circuit 230 described above is only one example of an embodiment of such a circuit. Those skilled in the art will have no difficulty considering other structures for creating an open circuit detection circuit.

If one or more open circuits are detected, the monitoring device may issue an error signal to alert an operator of the fault. The monitoring device can also be connected with a loom control device, and when an open circuit corresponding to the carbon yarn breakage is detected, a stop signal is sent to the loom control device to stop weaving, so that the loss of raw materials is minimized.

The invention makes it possible to monitor the correct positioning of the yarns and their integrity or continuity throughout the weaving process before starting the loom.