BE1020536A3 - DEVICE FOR INSERTING THE FRAME WIRE OF AN AIR JET TYPE WEAVING MACHINE. - Google Patents

Description

Weft insertion device of a jet loom of the air jet type.

The present invention relates to a weft insertion device of an air jet type loom, the weft insertion device being operable to insert a weft yarn by air jet. through a guide passage of the weft thread formed by tooth guide recesses and a leaf comb using nozzles and secondary weft insertion nozzles.

The air jet type loom has been developed to ensure the stability of weft insertion and the high speed of weft insertion. Japanese Patent Application Publication No. 5-86544 (first reference) discloses a weft insertion device for an air jet type loom. The profiled flap comb of the weft insertion device includes a plurality of teeth which are arranged side by side. Each tooth has a guide recess which is clear from the front surface of the tooth. Each guide recess is configured on its innermost wall and / or against other of its walls by means of a surface which is inclined such that the guide recess narrows in the direction of insertion. weft thread. The guiding passage for the weft yarn is subdivided into a first zone which is disposed near a main nozzle and a second zone which is disposed remote from the main nozzle. The wall surface of each tooth of the first zone of the guide passage for the weft thread has a first angle of inclination and the wall surface of each tooth of the second zone has a second angle of inclination. The second tilt angle is set to be greater than the first tilt angle.

Air jets from the main nozzle and the secondary nozzles meet each other in the first zone of the guide weight for the weft thread, so that a large amount of air in the guide passage for the weft yarn tends to flow through the front apertures of the guide recesses, causing the weft thread to move away from the guide passage for the weft yarn. To solve such a problem, air is allowed to escape from the guiding passage for the weft yarn towards the rear of the loom through the free spaces formed between two adjacent teeth by rendering the first inclination angle of the tooth wall surfaces of the first region of the guide passage for the weft yarn is zero or less. Thus, the weft yarn is prevented from flying out of the guide passage for the weft yarn, whereby the weft position of the weft yarn is suitably adjusted and the stability of the insertion of the weft yarn is thus achieved.

Further, according to the first reference, the air leakage from the guiding passage for the weft yarn is reduced towards the back of the loom by increasing the second wall surface tilt angle of the loom. teeth of the second zone of the guiding passage for the weft yarn, said wall surfaces being less affected by the jet of air from the main nozzle. Therefore, the flow of air is improved by increasing the air reflected by the tooth wall surface of the second area of the guide passage for the weft yarn. Thus, the improved airflow compensates for the deterioration in the rate of insertion of the weft yarn which is due to air leaking from the first zone towards the rear of the loom. weave.

In recent years, the development of jet weaving looms has been directed towards energy saving to take into account environmental problems. Japanese Patent Application Publication No. 46-3932 (second reference) discloses a weft insertion device for such an air jet type loom. The weft insertion device has a main nozzle and a plurality of secondary nozzles. In the second preference, it is suggested to reduce the air consumption of the secondary nozzles by reducing the size of the guide passage for the weft yarn (guide recess) formed in a flapper comb to guide a weft yarn. The main nozzle is disposed at the insertion side of the weft thread of the guide passage for the weft yarn parallel to the insertion direction of the weft yarn. When reducing the size of the weft guide passage as well as the distances between the secondary nozzles and the leaf comb in accordance with the reduced dimension of the guide passage for the weft yarn, it is to be feared that the Weft yarn ejected from the main nozzle reaches an inappropriate position of the first secondary nozzle or the first group of secondary nozzles, causing the weft thread to exit by stealing the guide passage for the weft yarn.

The injection hole * of each secondary nozzle is normally located at a suitable distance from the threshing edge of the flapper comb which forms the guide passage for the weft yarn as a function of the height of the guide passage for the yarn frame. However, to solve the problem indicated above, the insertion device of the weft thread of the second reference is made so that the injection hole of the first secondary nozzle or the first group of secondary nozzles comes to dispose of itself. at a distance from the threshing edge of the leaf comb, which is greater than the distance from the normal case to prevent the weft yarn from leaving by flying The guide passage for the weft yarn. The injection hole of the second secondary nozzle or the second group of secondary nozzles (or the injection hole of any secondary nozzle other than the first secondary nozzle or the first group of secondary nozzles) is available. successively closer to the threshing edge of the flapper comb to thereby correspondingly reduce the height of the guide passage for the weft yarn. Following the explanation provided in the second reference, we obtain a reduction of the air consumption as a whole. The height of the guide passage for the weft yarn can be reduced by varying the vertical spacing between upper and lower projections which form the guide passage for the weft yarn.

As described above, the gap between the injection hole and the threshing edge is reduced successively from the first secondary nozzle or from the first group of secondary nozzles towards the last secondary nozzle or the second nozzle. last group of secondary nozzles.

The weft insertion device disclosed in the first reference ensures the stability of the insertion of the weft yarn into the first region of the guide passage for the weft yarn by adjusting the first angle of inclination of the wall surfaces. teeth of the first zone to be smaller than the second inclination angle of the wall surfaces of the teeth of the second zone. In addition, the weft insertion device makes it possible to achieve a high speed of insertion of the weft yarn into the second zone.

The object indicated in the second reference is to reduce the air consumption by the secondary nozzles by reducing the gap between the injection hole and the threshing edge successively from the first secondary nozzle or from the first group of secondary nozzles towards the last secondary nozzle or the last group of secondary nozzles. When this method of the second reference is applied to the insertion device of the weft thread of the first reference, even if the inclination angle of the wall surfaces of the guide recesses for the teeth of the second is increased. the guide passage area for the weft yarn where the weft flight position is stabilized, especially in the first half of the second guide passage area for the weft yarn, the large desired speed for insertion of the weft yarn due to the large distance extending between the secondary nozzles and the flapper comb. In other words, a greater amount of air consumption is required to achieve the high speed desired for insertion of the weft yarn.

The present invention relates to a device for inserting the weft yarn of an air jet loom in which the air consumption for the insertion is reduced in the weft insertion device. weft yarn while maintaining the stability and high speed of insertion of the weft yarn.

SUMMARY OF THE INVENTION

In accordance with one aspect of the present invention, the weft insertion device of the air jet type loom having a leaf includes a plurality of weft insertion nozzles, a profiled leaf comb, and a plurality of weft insertion members. secondary nozzles. The weft insertion nozzles are mounted on the leaf to insert weft threads. At least one of the weft insertion nozzles is inclined with respect to the weft insertion direction so that the air stream from the weft insertion nozzle is directed towards the weft insertion direction. from the back of the loom. The profiled leaf comb is mounted on the leaf downstream of the weft insertion nozzles relative to the insertion direction of the weft yarn. The comb of the profiled leaf has several teeth which each have a guide recess. The teeth are arranged side by side so that the guide recesses form a guide passage for the weft yarn. Each tooth has an innermost wall forming part of the guide recess. The innermost wall has a surface that is inclined such that the guide recess narrows in the insertion direction of the weft yarn. The secondary nozzles are mounted on the front flap of the profiled leaf comb to inject air into the guide passage for the weft yarn. Each secondary nozzle has an injection hole. The guide passage for the weft yarn is subdivided into a first zone and a second zone which is disposed downstream of the first zone. The innermost wall of the first zone has an angle of inclination with respect to the insertion direction of the weft yarn which is smaller than that of the innermost wall of the second zone. The weft insertion device is characterized in that the distance extending between the injection hole of each secondary nozzle located in front of the first zone and any one of the innermost walls of the first zone closest to the injection hole of the secondary nozzle is greater than the distance extending between the injection hole of each secondary nozzle located at the front of the second zone and any one of the most the second zone closest to the injection hole of the secondary nozzle.

Other aspects and advantages of the invention will become apparent from the following description when taken in conjunction with the accompanying drawings which illustrate by way of example the principles of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention, together with its objects and advantages, can be better understood by reference to the following description of the presently preferred embodiments in conjunction with the accompanying drawings in which: Figure 1 is. a fragmentary sectional plan view showing a weft insertion device of an air jet type loom according to a first embodiment of the present invention; Figure 2 is an enlarged fragmentary plan view showing the weft insertion device of the air jet type loom of Figure 1; Figure 3 is a side view showing the weft insertion device of Figure 1; Fig. 4 is a partially sectional side view taken along the line A-A of Fig. 1; Fig. 5 is a partially sectional side view taken along the line B-B of Fig. 1; Fig. 6 is a schematic plan view showing a fixed block of a secondary nozzle of the weft insertion device; Fig. 7 is a side view showing a weft insertion device of an air jet type loom according to a second embodiment of the present invention; and FIG. 8 is a partial sectional plan view in which the weft insertion device of the air jet type loom of FIG. 7 is shown.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinafter, the weft insertion device of the air jet type loom according to the first embodiment of the present invention is described with reference to FIGS. 6. In the following description The jet loom of the air jet type will be referred to hereinafter simply as the "loom". Referring to Fig. 1 showing the weft insertion device of the air jet type loom, the underside of the drawing corresponds to the front of the loom, where the woven fabric is rolled up and the upper side corresponds to the back of the loom, where the warp yarn is unrolled.

The weft insertion device includes two weft insertion nozzles 2, 3 which are mounted on the leaf 1 of the loom. The weft insertion nozzle 2 extends parallel to the weft insertion direction and the weft insertion nozzle 3 is slightly inclined with respect to the insertion direction of the weft thread. such that the jet of air from the nozzle 3 is oriented slightly towards the rear of the loom. The weft yarn 5 which has been extracted from a weft yarn package (not shown) is passed and stored temporarily on the weft yarn measuring and storage device 4, through the weft insertion nozzle 2. We pass the weft thread 7 which has been extracted from a weft yarn package (which is not shown) and which has been temporarily stored on the measuring device and storing the weft thread 6, through the weft insertion nozzle 3.

A comb of the profiled leaf 9 and several (groups of) secondary nozzles 10A, 10B are mounted on the leaf 1 downstream of the weft insertion nozzles 2 and 3 with respect to the insertion direction of the weft thread. The comb of the profiled wing 9 has several teeth 8A and 8B. Referring to FIG. 4 in which the weft insertion device is shown, the view being taken along line AA of FIG. 1, it can be seen that each tooth 8A has a superior projection 11 and a lower projection 12, both projecting forwardly to thereby form a guide recess 13 open towards the front. Each guide recess 13 is formed by an innermost wall 13A, by the upper wall 13B of the upper projection 11 and by the bottom wall 13C of the lower projection 12. The guide recesses 13 of the teeth 8A are part of a guide passage 14 for the weft thread. Referring to FIG. 2, in which an enlarged partial plan view of the weft insertion device of FIG. 1 is shown, it can be seen that the innermost wall 13A of each tooth 8A has a surface which is inclined such that the recess narrows in the insertion direction of the weft yarn. The inclined surface of the innermost wall 13A forms a small angle of inclination Θ1. The comb of the profiled leaf 9 has at its top and at its base an upper frame 15 and a lower frame 16, respectively, which connects and binds the teeth 8A to each other, as shown in FIG. 4.

The teeth 8B are arranged side by side at places downstream of the teeth 8A, as shown in FIG. 2. Referring to FIG. 5, in which the weft insertion device is shown, the view being taken along the line BB of Figure 1, each tooth 8B has an upper projection 18 and a lower projection 19, both protruding forward to thereby form a guide recess 20 open to the front . Each guide recess 20 is formed by the innermost wall 20A, the upper wall 20B of the upper projection 18 and the lower wall 20C of the lower projection 19. The guide recesses 20 of the teeth 8B and the guide segments 13 of the teeth 8A form the passage 14 for guiding the weft thread. Thus, the teeth 8B have essentially the same configuration as the teeth 8A, when looking in the insertion direction of the weft yarn. As was the case with the surface of each innermost wall 13A, the innermost wall 20A of each tooth 8B has a surface that is inclined so that the recess narrows in the insertion direction of the wire. frame. As shown in Figure 2, the inclined surface of the. The innermost wall 20A forms an angle of inclination Θ2 which is greater than the angle of inclination Θ1 of the inclined surface to the innermost wall 13A of the tooth 8A.

As shown in FIGS. 1 and 2, the insertion passage of the weft yarn 14 is subdivided into a first zone L1 and a second zone L2. The first region L1 of the weft insertion passage 14 is disposed just downstream and extends over a portion of the weaving width from the weft insertion nozzles 2 and 3 and is formed by guide recesses 13 of the teeth 8A each having an inclination angle Θ1 of the inclined surface of the innermost wall 13A. The second zone L2 of the weft insertion passage 14 is disposed downstream of the first zone L2 extending over the remainder of the weaving width and formed by the guide recesses 20 of the teeth 8B, each having an angle d. inclination Θ2 to the inclined surface of the innermost wall 2 OA.

As shown in FIG. 1, four secondary nozzles 10A are disposed in front of the first zone L1 at a predetermined interval in the insertion direction of the weft yarn and a plurality of secondary nozzles 10B are also disposed in front of the second zone. L2 area at a predetermined interval in the insertion direction of the weft yarn. Four secondary nozzles 10A form a group and are connected to an air source (not shown) via a selection valve (not shown). Four respective secondary nozzles 10B form a group and are connected to an air source (not shown) via a selection valve (not shown). When looking in the insertion direction of the weft yarn, the first four secondary nozzles 10A, the four second secondary nozzles 10B, the four third secondary nozzles 10B, the fourth fourth secondary nozzles 10B and the fourthi second secondary nozzles 10B are represented by the first group, the second group, the third group, the fourth group and the nth group (not shown), respectively, as can be seen in FIG. 1. When the loom is actuated, the selection valves ( not shown) for the groups from the first group to the nth group are actuated one after the other relay to eject air from the respective secondary nozzles 10A and 10B.

Since the set of secondary nozzles 10A and 10B have essentially the same structure, the secondary nozzle 10A of Figure 4 will be used for the description of the secondary nozzles. For ease of explanation, the reference symbol A is added to the reference symbol at certain parts of the elements of the secondary nozzle 10A and the reference symbol B is added to the reference symbol at certain parts of the elements of the secondary nozzle 10B. The secondary nozzle 10A has a hollow elongate body 21A, a fixed block 22 in which the body 21A is mounted, a bolt 23 and a nut 24 which enable the fixed block 22 to be mounted on the wing 1. The body 21A has at its apex a injection hole 25A. The base of the body 21A is connected to its associated selection valve (not shown) by a flexible hose (not shown). The body 21A is inserted through the elongated hole 26 (as can be seen in FIG. 6) of the fixed block 22 could be fixed by the nuts 27 and 28.

As shown in FIG. 6, the elongated hole 26 of the fixed block 22 extends in the front-back direction of the loom and is formed through the fixed block 22. The fixed block 22 can take the form of an L when we look in a plan view. The fixed block 22 is mounted at the rear of the loom in a groove of the wing 1 and is fixed to the wing 1 by a bolt 23 inserted in a groove 29 in the dovetail of the wing 1 and via its nut 24.

Each of the secondary nozzles 10A 'disposed in front of the first zone L1 of the guide passage 14 for the weft thread is fixed to the wing 1 so that the body 21A is disposed at the end of the front side of the elongated hole 26, as can be seen in FIG. 6, and in such a way that the injection hole 25A is located at a distance Q1 (as can be seen in FIG. 4) from the fixed block 22. Thus, each secondary nozzle 10A is arranged such that the injection hole 25A of the secondary nozzle 10A is located at a distance PI (as can be seen in FIG. 4) from any of the innermost walls 13A of the teeth 8A. closer to the injection hole 25A of the secondary nozzle 10A.

Each of the secondary nozzles 10B arranged in front of the second zone L2 of the guiding passage 14 for the weft thread is fixed to the wing 1 so that the body 21B is disposed at the end of the rear side of the elongated hole 26, as can be seen in FIG. 6, and in such a way that the injection hole 25B of the secondary nozzle 10B is located at a distance Q2 (as can be seen in FIG. 5) from the fixed block 22. Thus, each secondary nozzle 10B is arranged such that the injection hole 25B of the secondary nozzle 10B is located at a distance P2 (as can be seen in FIG. 5) from any of the innermost walls 20A of the 8B teeth closest to the injection hole 25B of the secondary nozzle 10B.

As can be seen in Figures 2 and 3, the secondary nozzles 10A and 10B are mounted on the flap 1, so that the distance PI is greater than the distance P2 by a difference ΔΡ. The difference ΔΡ can be obtained by arranging the bodies 21A and 21B at a distance, as can be seen in the front-to-back direction of the loom. Specifically, in the illustrated embodiment, each body 21A is mounted on its fixed block 22 so that the body 21A is disposed at the front end of the elongated hole 26, so that the injection hole 25A is positioned at the distance PI with respect to the innermost wall 13A having the angle of inclination Θ1. In this way, the secondary nozzle 10A is disposed away from the innermost walls 13A at a suitable distance. Each body 21B is mounted on its fixed block 22 so that the body 21B is disposed at the rear end of the elongated hole 26, so that the injection hole 25B is positioned at the distance P2 relative to the the innermost wall 20A having the angle of inclination Θ2. In this way, the secondary nozzle 10B is disposed at a place as close as possible to the innermost walls 20A.

By positioning the injection hole 25A of each secondary nozzle 10A at a location less than that of the injection hole 25B of each secondary nozzle 10B by the difference AQ, the direction of the air jets of the injection holes 25A and 25B of the secondary nozzles 10A and 10B are close to each other or coincide with each other as shown in FIG. Such an arrangement of the secondary nozzles 10A and 10B is preferred because the air jets from the injection holes 25A and 25B are oriented in substantially the same positions of the respective guide recesses 13 and 20. It should be noted, however, that the difference AQ may be equal to zero as long as the distance PI is set to be greater than the distance P2.

Hereinafter, the operation and effect of the weft insertion device according to the first embodiment of the present invention is described. The jet of air ejected by the weft insertion nozzle 2 for insertion of the weft yarn flows downstream in the direction of insertion of the weft yarn while being diffused in the guide passage of the yarn. frame 14 and joins the jets of air ejected by the respective secondary nozzles 10A of the first group. Each secondary nozzle 10A of the first group ejects air from the distance PI and the inclined surface of the innermost wall 13A of each tooth 8A is adjusted to obtain the angle of inclination Θ1. 8A teeth

having such an inclined surface prevent air from flowing out of the guide passage 14 for the weft yarn towards the front of the loom, but allow air to flow out of the guide passage 14 for the weft yarn towards the back of the loom through the free spaces between the teeth 8A, in a manner that is appropriate. Thus, the insertion device of the weft yarn makes it possible to increase the flight speed of the weft yarn 5 while maintaining the stabilized flight position of the weft yarn 5. Consequently, the stability of the insertion is improved. weft yarn in the first zone L1.

When the weft thread 5 reaches the second zone L2, the weft thread 5 is conveyed by the jets of air ejected by the secondary nozzles 10B from the groups going from the second group to the nth group. The secondary nozzles 10B for the second zone L2 are arranged at a distance P2 from the innermost walls 20A and the inclined surface of the innermost wall 20A of each tooth 8A has the angle of inclination Θ2, so that one reduces the flow of air jets that are ejected by the secondary nozzles 10B. That is, most of the air injected into the second zone L2 is reflected back towards the center of the guide passage for the weft yarn 14 by the innermost walls 20A, the major part being used effectively as transport air for the weft yarn 5. Therefore, when the amount of air ejected by the secondary nozzles 10B is less than that ejected by the secondary nozzles 10A, a transport is carried out. Successful weft yarn 5 is achieved via the reduced air jet and a weft insertion rate is also obtained which corresponds to the higher rotational speed of the loom. Therefore, the air consumption is substantially reduced by the secondary nozzles 10B which are arranged in front of the second zone L2, while maintaining the high insertion speed of the weft thread. In this way, the air flow ejected by the weft insertion device is reduced.

When the insertion of the weft yarn is carried out by an air jet coming from the insertion nozzle of the weft yarn 3, injection air flows towards the innermost walls 13A of the teeth 8A of the first zone L1. Since the angle of inclination Θ1 of the inclined surface of the innermost wall 13A is set to be small, it is reduced to. both the air leakage from the first zone L1 of the guide passage 14 for the weft yarn towards the rear of the loom through the free spaces between the teeth 8A and the air reflection by the innermost wall 13A. Therefore, the weft insertion device increases the flight speed of the weft yarn 7 while maintaining the stabilized flight position of the weft yarn 7. The flight of the weft yarn into the second zone L2 of the weft passage guidance for the weft yarn 14 is implemented in the same way as in the case in which the insertion of the weft yarn is carried out by the jet of air ejected by the insertion nozzle of the weft yarn 2.

Therefore, the air consumption is substantially reduced by the secondary nozzles 10B which are arranged in front of the second zone L2, while maintaining the stability and the high speed of insertion of the weft thread. In this way, the ejected air stream is reduced by the weft insertion device.

In the first embodiment, the bodies 21A and 21B of the secondary nozzles 10Δ and 10B are mounted on the fixed blocks 22 by means of the elongated holes 26, so that the bodies 21A and 21B are mounted at different positions in the direction front to back of the looms to get the difference ΔΡ between the distances PI and P2. Thus, the difference ΔΡ is adjusted according to the requirements according to the type of weft yarn to be inserted and according to the rotational speed of the loom. In either case, the air consumption of the secondary nozzles is substantially reduced. Furthermore, since the injection hole 25A of each secondary nozzle 10A is disposed at a location less than that of the injection hole 25B of each secondary nozzle 10B up to the difference AQ, the directions of the air jets injection holes 25A and 25B of the secondary nozzles 10A and 10.B are close to each other or coincide with each other. Such an arrangement of secondary nozzles 10A and 10B is preferred since the air jets ejected by the injection holes 25A and 25B are oriented in substantially the same positions of the respective guide recesses 13 and 20. Therefore, still more the stability of the insertion of the weft thread.

Hereinafter, the weft insertion device of the air jet type loom according to the second embodiment of the present invention is described with reference to FIGS. 7 and 8. The second embodiment of FIG. The embodiment differs from the first embodiment with respect to the configuration of the lower walls of the teeth corresponding to the teeth 8A of the first embodiment. For ease of explanation, like or like elements in the second embodiment will be designated by the same reference numerals as used in the first embodiment and their description will be omitted. In the second embodiment, a plurality of teeth 8C corresponding to the teeth 8A of the first embodiment have upwardly open guide recesses 30. The guide recesses 30 of the teeth 8C and the guide recesses 20 of the teeth 8B form the guide passage 14 for the weft thread.

Each tooth 8C has an upper projection 30 and a lower projection 32, both protruding forwardly. Each guide recess 30 is formed by the innermost wall 30A, the upper wall 30B of the upper projection 31 and the lower wall 30C of the lower projection 32. The lower projection 32 of each tooth 8C extends further towards the before the lower projection 19 of each tooth 8B according to the arrangement in which the secondary nozzles 10Δ are disposed more forwardly than the secondary nozzles 10B. Thus, the bottom wall 30C of each guide recess 30 is longer in the front-to-back direction of the loom than the bottom wall 20C of each guide recess 20. Therefore, a distance between the injection hole is obtained. 25A of each secondary nozzle 10A and the lower projection 32 substantially identical to the distance extending between the injection hole 25B of each secondary nozzle 10B and the lower projection 19.

The flow of the jets of air ejected by the secondary nozzles 10A outside the guiding passage 14 for the weft yarn is prevented by the reduction of the distance between the bottom wall 30C and the injection hole 25A. As a result, air is ejected into the guideway 14 of the weft yarn effectively to thereby stabilize the insertion of the weft yarn.

The present invention has been described in the context of the above embodiments, but is not limited to these embodiments. It is clear to those skilled in the art that the invention can be implemented in a variety of ways as illustrated below by way of example.

In each of the embodiments, the position of the bodies 21A, 21B of the secondary nozzles 10A, 10B may be adjusted relative to the fixed blocks 22 in the front-rear direction of the loom to adjust the distances PI, P2 to n '. any desired value. However, the position can be arranged so that the bodies 21A, 21B of the secondary nozzles 10A, 10B are fixed to the fixed blocks 22 and the position of the fixed blocks 22 can be made adjustable with respect to the wing 1 in the front-to-back direction of the loom. In this case, it is possible to freely adjust the distances PI, P2, for example by inserting any element such as a spacer between the fixed block 22 and the wing 1. The position of the secondary nozzles 10A, 10B can be made adjustable in the front-to-back direction of the loom using any other suitable means.

The number of the secondary nozzles 10A or 10B of a group is not limited to four: it can be two or more. Alternatively, the number of the secondary nozzles 10A or 10B may be different from one group to another.

The number of secondary nozzle groups 10A disposed in front of the first zone L1 of the guide passage 14 for the weft yarn is not limited to one: this number may be two or more.

In each embodiment, two weft insertion nozzles 2 and 3 are illustrated. However, three or more weft insertion nozzles may be used, at least one of these nozzles being inclined relative to the insertion direction of the weft yarn such that the air ejected from such a nozzle is oriented slightly towards the rear of the loom.

Thus, the present invention can be applied to a loom that produces an alternating weave or polychrome weave using three or more weft insertion nozzles of this type.

Claims (6)

A weft insertion device of an air jet type loom having a leaf (1), the weft insertion device comprising: a plurality of weft insertion nozzles (2, 3) which are mounted on the leaf (1) for inserting weft threads (5, 7), at least one of the weft insertion nozzles (2, 3) being inclined with respect to the insertion direction of the weft yarn, whereby the air jet emitted by the weft insertion nozzle (3) is directed towards the rear of the loom; a comb of the profiled leaf (9) mounted on the leaf (1) downstream of the weft insertion nozzles (2, 3) with respect to the direction of insertion of the weft thread, the comb of the profiled leaf ( 9) having a plurality of teeth (8A, 8B, 8C) each having a guide recess (13, 20, 30), the teeth (8A, 8B, 8C) being arranged side by side, so that the guide recesses ( 13, 20, 30) form a guide passage (14) for the weft thread, the guide passage (14) for the weft thread being subdivided into a first zone (L1) and a second zone (L2) which is disposed downstream of the first zone (L1), each tooth (8A, 8B, 8C) having an innermost wall (13A, 20A, 30A) forming part of the guide recess (13, 20, 30) the innermost wall (13A, 20A, 30A) having a surface which is inclined such that the guide recess (13, 20, 30) tapers in the insertion direction of the weft yarn, the the innermost king (13A, 30A) of the first zone (Ll) forming an inclination angle (Θ1) with respect to the direction of insertion of the weft yarn which is smaller than the angle formed by the most internal (20A) of the second zone (L2); and a plurality of secondary nozzles (10A, 10B) mounted on the wing. (1) at the front of the fin-profile comb (9) for injecting air into the weft guide passage (14), each secondary nozzle (10A, 10B) having an injection hole ( 25A, 25B); the weft insertion device being characterized in that the distance (PI) extending between the injection hole (25A) of each secondary nozzle (10A) located in front of the first zone (L1) and any one of the innermost walls (13A, 30A) of the first zone (L1) nearest the injection hole (25A) of the secondary nozzle (10A) is greater than the distance (P2) s' extending between the injection hole (25B) of each secondary nozzle (10B) located in front of the second zone (L2) and any one of the innermost walls (20A) of the second zone (L2) the closer to the injection hole (25B) of the secondary nozzle (10B). 2. Weft insertion device of the air jet type loom according to claim 1, characterized in that it is arranged to obtain an adjustable position of each secondary nozzle (10A, 10B). in the front-to-back direction of the loom. Weft insertion device of the air jet type loom according to claim 2, characterized in that each secondary nozzle (10A, 10B) has a body (21A, 21B) and a fixed block (22) having an elongate hole (26) extending in the forward-backward direction of the loom, a position of the body (21A, 21B) being adjustable in the elongated hole (26). Weft insertion device of the air jet type loom according to claim 2, characterized in that each secondary nozzle (10A, 10B) has a fixed block (22) and a body (21A). , 21B) which is fixed to the fixed block (22), a position of the fixed block (22) being made adjustable with respect to the leaf (1) in the front-back direction of the loom. Weft insertion device of the air jet type loom according to claim 2, characterized in that the injection hole (25A) of each secondary nozzle (10A) located at the front of the first zone (L1) is placed in a position lower than that of the injection hole (25B) of each secondary nozzle (10B) situated in front of the second zone (L2). 6. Weft insertion device of the air jet type loom according to any one of claims 1 to 5, characterized in that a bottom wall (30C) forming part of the recess. for guiding (30) the first zone (L1) is longer in the front-back direction of the loom than a lower wall (20C) forming part of the guide recess (20) of the second zone ( L2).