TECHNICAL FI ELD AND PRIOR ART

[0001 ] The invention relates to a mounting device for mounting a nozzle arrangement on an air- jet weaving machine. The invention further relates to a nozzle arrangement with a mounting device.

[0002] In air-jet weaving machines, weft threads are transported from an insertion side to the opposite side in an insertion channel of a reed mounted on the sley. During weaving, different weft threads are successively inserted, for example weft threads, which differ in color. For this purpose, it is known to provide a plurality of nozzles, each of which is intended for the insertion of one associated weft thread. The plurality of nozzles is referred to as nozzle arrangement in the context of the application. It is known to arrange all nozzles fixed in position, wherein the position is chosen so that all front ends of the nozzles are best possible aligned with the insertion channel at all times. Further, nozzle arrangements are known, wherein the nozzles and/or front ends of the nozzles are movably mounted on the sley to adjust the position of the front end of a nozzle, i.e. the front outlet end of a nozzle, in use with the insertion channel. The adjusted position of a front end of a nozzle for an insertion is referred to as "use position" in the context of the application. The use position in preferred embodiments is in the extension of the insertion channel. However, other use positions are conceivable.

[0003] US 4,962,795 shows a nozzle arrangement and a mounting device for the nozzle arrangement, with a front nozzle support comprising a positioning part arranged in a guide recess, and a pneumatic piston cylinder device having a piston rod bearing against the lower side of the positioning part. A movement of the piston rod displaces the positioning part within the guide recess for an adjustment of nozzle outlets relative to an insertion channel of a reed. A rear end or inlet end of the nozzle arrangement is mounted using a spring elastic element. [0004] US 4,703,778 shows a nozzle arrangement for a weaving machine having a sley and a reed with an insertion channel therein, said nozzle arrangement comprising: a plurality of pairs of nozzles, each nozzle having a back end terminating in a nozzle body and having a front end terminating in a discharge opening; first mounting means for pivotally mounting said nozzle body on the sley of a loom with said nozzle front ends pivotal in a vertical direction; pneumatic drive means; compression spring means; second mounting means for mounting said nozzle front ends on the sley with one of said pairs of said discharge openings substantially aligned with the insertion channel, with the nozzles of each pair closely juxtaposed and aligned in horizontal rows, and with the pairs closely juxtaposed in two vertical rows, said second mounting means positioning said nozzle front ends between and substantially aligned with said pneumatic drive means and said compression spring means; and actuating means controlling said pneumatic drive means for moving said nozzle front ends vertically against the force of said compression spring means, thus vertically pivoting said nozzle front ends to move said nozzles between positions vertically aligning each of said pairs of discharge openings with the insertion channel, permitting positioning of said pairs of nozzles for discharging weft threads from the nozzles of the aligned pair into the insertion channel. [0005] US 4,572,246 shows a nozzle arrangement comprising a plurality of nozzles, in particular four nozzles, joined in a bundle and carried by a body, said body being mounted on two supports arranged at 90° from one to another, and two actuators each adapted to be operated for imparting to said supports a rectilinear movement in one direction, wherein the two actuators can be operated simultaneously or separately for positioning the body in a plane perpendicular to the insertion direction.

SUMMARY OF THE I NVENTION

[0006] It is the object of the present invention to provide a mounting device for mounting a nozzle arrangement at an air-jet weaving machine and a nozzle arrangement with a mounting device, wherein the position of a positioning part of a front nozzle support can be adjusted for reliably bringing a selected front outlet end of one of N insertion nozzles into a use position with respect to an insertion channel of a reed.

[0007] According to a first aspect, a mounting device for mounting a nozzle arrangement comprising N insertion nozzles, wherein N is at least three, on an air-jet weaving machine comprising a reed with an insertion channel is provided, the mounting device comprising a guide sleeve with a guide recess having a polygonal cross-section with at least N side surfaces, and a front nozzle support for supporting front ends of the N insertion nozzles with a positioning part having a polygonal cross-section with at least N contact surfaces, wherein the positioning part is arranged in the guide recess, wherein in a direction transversely to the insertion channel, the positioning part is moveable within the guide recess into N insertion positions each associated with one of the N insertion nozzles, wherein in each insertion position of the N insertion positons a pair of two non-parallel contact surfaces abuts against side surfaces of the guide recess and one of the N insertion nozzles is brought into its use position with respect to the insertion channel, in particular a front end of one of the N insertion nozzles is brought into its use position with respect to the insertion channel.

[0008] The mounting device preferably comprises a reed support for coupling the mounting device at a selected axial position to the reed. The front ends of the nozzles are moveable within a limited range in a direction transversely to the insertion channel for bringing a front end of a selected one of the insertion nozzles into a use position.

[0009] In the context of the application, the expression "direction transversely to the insertion channel" is used for any direction in a plane perpendicular to the insertion direction. For example, the positioning part is moveable in a vertical direction, in a horizontal direction or in a direction having a vertical and a horizontal component. Each use position is independent of the other use positions and is chosen such that the associated insertion nozzle is positioned in a best way.

[0010] In preferred uses of the mounting device, a front end of an insertion nozzle for inserting a subsequent weft thread is brought into its use position with respect to the insertion channel in the reed just before the insertion and, preferably, is kept in its use position until the inserted weft thread is bound by the warp threads. Thereafter, the front end of the subsequent insertion nozzle for the insertion of a subsequent weft thread is brought into its use position. The moments for repositioning the front ends of the insertion nozzles can be set in a control unit.

[001 1 ] In each insertion position, the positioning part abuts with two non-parallel contact surfaces against side surfaces of the guide recess. Hence, a precise positioning is repeatedly possible and independent of variations in forces applied for moving the positioning part.

[0012] The cross-section of the positioning part and the cross-section of the guide recess in preferred embodiments have geometric similarity, i.e. they have the same shape but differ in size and the cross-section of the guide recess can be obtained from the cross-section of the positioning part by uniformly enlarging the cross-section of the positioning part.

[0013] The mounting device is in particular suitable for nozzle arrangements comprising four insertion nozzles, wherein a compact system is provided. In addition, the mounting device is also suitable for nozzle arrangements having three, five, six, seven, eight, nine or even more insertion nozzles. For example, in case the nozzle arrangement comprises three insertion nozzles, a guide recess and a positioning part both having a triangular cross-section with geometric similarity are provided. Hence, the positioning part can be moved into each of the three corners of the triangular guide recess, wherein two contact surfaces sandwiching the corner abut against two side surfaces of the guide recess.

[0014] In one embodiment, for different insertion positions the angles between the associated two non-parallel contact surfaces abutting against side surfaces of the guide recess differ. In a preferred embodiment, each pair of contact surfaces abutting against side surfaces in an insertion position is arranged at an angle a = (N-2)/N x 180° and the associated pair of side surfaces is arranged at the same angle a. In other words, the contact surfaces and the side surfaces are each arranged along equiangular polygons.

[0015] In one embodiment, in alternative or in addition, the polygons are equilateral, i.e. all sides of one polygon have the same length. In preferred embodiments, the cross-section of the positioning part and the cross-section of the guide recess is a regular polygon, i.e. a polygon that is equiangular and equilateral.

[0016] In one embodiment, contact surfaces of each pair of contact surfaces abutting against side surfaces in an insertion position and/or corresponding side surfaces meet at a vertex. [0017] In alternative, contact surfaces of each pair of contact surfaces abutting against side surfaces in an insertion position and/or corresponding side surfaces meet at truncated corners. The truncated corners are advantageous for avoiding a mechanical over-determination due to machining tolerances. In addition, by providing truncated corners force receiving surfaces can be formed, as described in more detail below. [0018] The insertion nozzles in preferred embodiments are arranged at corners of an imaginary polygon, in particular an imaginary regular polygon. In one embodiment, the nozzle arrangement only comprises the N insertion nozzles. In other embodiments, additional nozzles are provided, wherein the additional nozzles can also be brought into a use position. However, the use position of the additional nozzles is not defined by two non-parallel contact surfaces abutting against side surfaces of the guide recess. One example of an additional nozzle is a central nozzle arranged at the center of the positioning part. The design and/or the function of the additional nozzle or the additional nozzles in one embodiment is identical to that of the N insertion nozzles. Hence, the additional nozzles are also referred to as additional insertion nozzles in the context of the application. [0019] In a preferred embodiment, the N insertion nozzles are arranged at corners of an imaginary regular polygon, wherein in particular at least one additional insertion nozzle is provided inside the imaginary regular polygon.

[0020] In preferred embodiments, the mounting device further comprises an actuator device, which actuator device is arranged for forcing the positioning part into selected ones of the N insertion positions associated with one of the N insertion nozzles. The actuator device in one embodiment comprises electro-magnetic means for magnetically attracting the positioning part, thereby forcing the positioning part in a selected position.

[0021 ] In preferred embodiments, the actuator device comprises N linear actuators, wherein each linear actuator is arranged for forcing the positioning part into a selected one of the N insertion positions associated with one of the N insertion nozzles. In case the nozzle arrangement further comprises additional nozzles, in one embodiment, two or more of the N linear actuators can be driven to force the positioning part into an insertion position associated with the additional nozzles. [0022] In preferred embodiments, each linear actuator comprises at least one piston-cylinder actuator, preferably two or three piston-cylinder actuators. The piston-cylinder actuators preferably are pneumatic piston-cylinder actuators. However, embodiments with electrical and/or hydraulic actuators are also conceivable. By providing a plurality of piston-cylinder actuators the size of each piston-cylinder actuator can be reduced, while still providing a sufficient force for moving the positioning part.

[0023] In the insertion positions associated with the insertion nozzles the two non-parallel contact surfaces abut against side surfaces of the guide recess. The two non-parallel contact surfaces preferably sandwich a corner region. A force is applied at a surface of the positioning part opposite the corner region. In case N is an uneven number, and the positioning part has the form of a regular polygon, a flat surface is provided opposite each corner region, which flat surface can be used for receiving a force. In case N is an even number, and the positioning part has the form of a regular polygon, further corner regions are provided opposite each corner region. In one embodiment, as described above, contact surfaces of each pair of contact surfaces abutting against side surfaces in an insertion position and/or associated side surfaces meet at truncated corners. Due to the truncation, flat surfaces are formed which can be used as force receiving surfaces. [0024] In an alternative embodiment, the front nozzle support is provided with a force receiving part with N force receiving surfaces for receiving a force from a linear actuator associated with one of the N insertion nozzles.

[0025] In case N is an even number and the cross-section of the force receiving part and the cross-section of the positioning part are regular polygons having geometric similarity, in one embodiment the force receiving part is arranged with an angular difference to the positioning part. The angular difference preferably is β = 1807N.

[0026] The mounting device in one embodiment further comprises a rear guide sleeve with a guide recess and a rear nozzle support for supporting rear ends of the N insertion nozzles. In one embodiment, the rear nozzle support is formed identical or similar to the front nozzle support, wherein the insertion nozzles are displaced in parallel by means of the front nozzle support and the rear nozzle support. In preferred embodiments, the rear nozzle support is a passive device, wherein the rear nozzle support is supported in the rear guide sleeve using at least one elastically deformable element. [0027] In one embodiment, the rear nozzle support and the guide recess of the rear guide sleeve each have an at least essentially rectangular cross-section.

[0028] According to an embodiment, the rear nozzle support is supported in the rear guide sleeve using at least one elastically deformable element, preferably an elastically deformable element having the shape of a cylinder, preferably the shape of a circular cylinder, which at least one elastically deformable element is pressed between the rear nozzle support and the guide recess of the rear guide sleeve. When moving the front nozzle support into a selected position, the rear nozzle support is tilted. The elastically deformable element having the shape of a cylinder allows a pivot movement of the rear nozzle support about the cylinder axis. Hence, the rear nozzle support can be easily tilted upon moving the front nozzle support and, compared to supports having a rectangular rubber element, less force is required for moving the front nozzle support into its use position.

[0029] In one embodiment, the rear nozzle support and the guide recess of the rear guide sleeve each have an at least essentially rectangular cross-section, wherein the rear nozzle support is supported in the rear guide sleeve using four elastically deformable elements, in particular four rubber elements, having the shape of a cylinder, in particular the shape of a circular cylinder, which elastically deformable elements are pressed between the rear nozzle support and the guide recess of the rear guide sleeve, in particular four elastically deformable elements arranged in a square.

[0030] According to a second aspect, a nozzle arrangement on an air-jet weaving machine comprising a reed with an insertion channel is provided, the nozzle arrangement comprising N insertion nozzles, wherein N is at least three, and a mounting device comprising a guide sleeve with a guide recess having a polygonal cross-section with at least N side surfaces, and a front nozzle support for supporting front ends of the N insertion nozzles with a positioning part having a polygonal cross-section with at least N contact surfaces, wherein the positioning part is arranged in the guide recess, wherein in a direction transversely to the insertion channel, the positioning part is moveable within the guide recess into N insertion positions each associated with one of the N insertion nozzles, wherein in each insertion position of the N insertion positons a pair of two non-parallel contact surfaces abuts against side surfaces of the guide recess and one of the N insertion nozzles is brought into its use position with respect to the insertion channel. BRI EF DESCRIPTION OF THE DRAWINGS

[0031 ] In the following, an embodiment of the invention will be described in detail with reference to the drawings. Throughout the drawings, the same elements will be denoted by the same reference numerals.

Fig. 1 : is a perspective view of a nozzle arrangement according to an embodiment mounted on an air-jet weaving machine by using a mounting device;

Fig. 2: is an explosive view of the nozzle arrangement of Fig. 1 ;

Fig. 3: is a cross-sectional view of the nozzle arrangement of Fig. 1 seen from a front end of the nozzle arrangement;

Fig. 4: is a sectional side view of the nozzle arrangement of Fig. 1 ; Fig. 5: are schematic views of a mounting device for a nozzle arrangement of Fig. 1 having four nozzles, with a positioning part of the mounting device in a central position and in four insertion positions; Fig. 6: are schematic views of a mounting device for a nozzle arrangement having three nozzles, with a positioning part of the mounting device in a central position and in three insertion positions;

Fig. 7: are schematic views of a mounting device for a nozzle arrangement having five nozzles, with a positioning part of the mounting device in a central position and in five insertion positions;

Fig. 8: are perspective views of a mounting device for a nozzle arrangement having six nozzles, with a positioning part of the mounting device in a central position and in six insertion positions; Fig. 9: are schematic views of the mounting device of Fig. 8 for a nozzle arrangement having six nozzles, with a positioning part of the mounting device in a central position and in six insertion positions;

Fig. 10: are schematic views of a mounting device for a nozzle arrangement having seven nozzles, with a positioning part of the mounting device in a central position and in seven insertion positions; and

Fig. 1 1 : are schematic views of a mounting device for a nozzle arrangement having eight nozzles, with a positioning part of the mounting device in a central insertion position and in seven further insertion positions according to the invention.

DETAI LED DESCRI PTION OF EMBODIMENTS OF THE I NVENTION [0032] Fig. 1 shows in a perspective view a nozzle arrangement 1 mounted on an air-jet weaving machine by using a mounting device 5. To facilitate the understanding of the drawing, only parts of the weaving machine, namely the sley 7 and the reed 9 mounted to the sley 7 are shown, so that the details according to the invention are more readily apparent. As generally known, the reed 9 is provided with an insertion channel 1 1 . [0033] In the embodiment shown, a reed support 13 is provided for coupling the mounting device 5 of the nozzle arrangement 1 at a selected axial position along the sley 7 to the reed 9. [0034] The nozzle arrangement 1 shown in Fig. 1 comprises four insertion nozzles 15. Front ends of the insertion nozzles 15 are mounted to a front nozzle support 16 having a positioning part 17. Rear ends of the insertion nozzles 15 are mounted to a rear nozzle support 19. At the rear nozzle support 19 connectors 21 for a supply of compressed air (not shown) to the insertion nozzles 15 are provided.

[0035] The mounting device 5 comprises a front guide sleeve 23 with a front guide recess 25 arranged at a front end of the mounting device 5, wherein the positioning part 17 is arranged in the front guide recess 25.

[0036] The mounting device 5 further comprises a rear guide sleeve 27 with a rear guide recess 29, wherein the rear nozzle support 19 is arranged in the rear guide recess 29.

[0037] The mounting device 5 further comprises a protective cover 31 enclosing the insertion nozzles 15. In the embodiment shown, the protective cover 31 is formed integrally, in other words in one piece, with the positioning part 17 and is screwed at its rear end to the rear nozzle support 19. [0038] The nozzle arrangement 1 is shown in more detail in Figs. 2 to 4.

[0039] As best seen in the explosive view of Fig. 2, in the embodiment shown, a nozzle holder 33 is provided for holding front ends of the insertion nozzles 15, wherein the nozzle holder 33 is supported by the positioning part 17. The nozzle holder 33 is positioned fixed in position in the positioning part 17. In the embodiment, the nozzle holder 33 and the positioning part 17 are non-rotatably and non-moveably in a direction transversely to the insertion channel 1 1 (see Fig. 1 ) connected with a positive locking connection. In the embodiment shown, the positioning part 17 and the nozzle holder 33 have geometric similarity. In other embodiments, the form of the nozzle holder 33 differs from that of the positioning part 17. In still another embodiment, the positioning part 17 is formed integrally, in other words in one piece, with the nozzle holder 33. [0040] For allowing a mounting of the positioning part 17 in the guide recess 25 of the guide sleeve 23, in the embodiment shown the guide sleeve 23 comprises a first guide sleeve part 35 and a second guide sleeve part 37, which are connected to each other.

[0041 ] The positioning part 17 is moveably arranged in the guide recess 25 into four insertion positions, wherein each insertion position is associated with a use position of one of the four insertion nozzles 15, in particular a use position of a front outlet end of one of the four insertion nozzles 15. In the embodiment shown, the mounting device 5 comprises an actuator device 39, which actuator device 39 is arranged for forcing the positioning part 17 into a selected one of the four insertion positions associated with one of the four insertion nozzles 15. More particular, in the embodiment shown, the actuator device 39 comprises four linear actuators 41 , wherein each linear actuator 41 is arranged for forcing the positioning part 17 along a straight line into a selected one of the four insertion positions associated with one of the four insertion nozzles 15.

[0042] In the embodiment shown, each linear actuator 41 comprises three piston-cylinder actuators with pistons 43 arranged in cylinders. Each of the piston-cylinder actuators is small in size, wherein the use of a plurality of small actuators for each linear actuator 41 allows to use small actuators and nevertheless obtain the required force. Such actuators are compact and can be driven at a relative low pressure in order to exert a sufficient force for moving the positioning part 17 within the guide recess 25.

[0043] In the embodiment shown, at a rear end of the nozzle arrangement 1 , the insertion nozzles 15 are passively supported by means of the rear nozzle support 19 and the rear guide sleeve 27. For allowing a mounting of the rear nozzle support 19 in the guide recess 29 of the rear guide sleeve 27, in the embodiment shown the guide sleeve 27 comprises a first guide sleeve part 45 and a second guide sleeve part 47, which are connected to each other.

[0044] The rear nozzle support 19 is supported in the rear guide sleeve 27 using four elastically deformable elements 49 having the shape of a circular cylinder, for example rubber elements 49. The elements 49 are pressed between the rear nozzle support 19 and the guide recess 29 of the rear guide sleeve 27. The rear nozzle support 19 has a square cross-section and the elements 49 are arranged at the four sides of the nozzle support 19 with their axial direction in parallel to the associated side and perpendicular to the insertion direction. In the embodiment shown, the rear nozzle support 19 is provided with an annular groove 50 for receiving the elements 49. Similar, the guide sleeve 27 is provided with notches 52 for receiving the elements 49. This is particularly advantageous for pressing the elements 49 between the rear nozzle support 19 and the guide recess 29 of the rear guide sleeve 27.

[0045] When moving the positioning part 17 into a selected insertion position, the protective cover 31 formed integrally with the positioning part 17 and the rear nozzle support 19 screwed to the protective cover 31 are tilted. Due to the rolling effect of the cylinder shaped elements 49, a resilient force against the tilting movement of the rear nozzle support 19 in the guide sleeve 27 is small. The elements 49 are always pressed together, so that they are not subjected to traction forces and have a long life time. This is particularly advantageous in case rubber elements 49 are used.

[0046] As best seen in Fig. 3, in the embodiment comprising four insertion nozzles 15, the positioning part 17 comprises four contact surfaces 51 arranged at angles of 90°. In other words, the four contact surfaces 51 together form a square. In the embodiment shown, the corners between adjacent contact surfaces 51 are truncated for forming force receiving surfaces 53. A cross-section of the guide recess 25 has geometric similarity to the cross-section of the positioning part 17 and comprises four side surfaces 55 arranged at angles of 90°.

[0047] In accordance with the application, in order to allow for a precise, reliable and repeatable positioning of the positioning part 17 within the guide recess 25, the positioning part 17 in each insertion position abuts with two non-parallel contact surfaces 51 against two side surfaces 55 of the guide recess 25. For forcing the positioning part 17 against the associated two side surfaces 55 of the guide recess 25, a linear force is applied at the force receiving surface 53 formed opposite a corner region formed by the two non-parallel contact surfaces 51 . [0048] Fig. 5 shows in schematic views the mounting device 5 having four insertion nozzles 15, wherein the positioning part 17 is moved into a central position and in four insertion positions, each associated with one insertion nozzle 15. In the central position of the positioning part 17 shown on the left, none of the linear actuators 41 is activated. In the state shown second from the left in the upper row, the linear actuator 41 arranged at the top is activated and the piston 43 applies a force to the force receiving surface 53 arranged at the top in Fig. 5, thereby causing a linear movement of the positioning part downwards in Fig. 5 until two contact surfaces 51 arranged at either side of a truncated corner opposite the active piston 43 contact two side surfaces 55 of the guide recess 25. In the state shown on the right in the upper row, the linear actuator 41 arranged at the left is activated and the respective piston 43 applies a force to the force receiving surface 53 arranged at the left in Fig. 5, thereby causing a linear movement of the positioning part to the right in Fig. 5 until two contact surfaces 51 arranged at either side of a truncated corner opposite the active piston 43 contact two side surfaces 55 of the guide recess 25. In the state shown on the left in the lower row, the linear actuator 41 arranged at the bottom is activated and the respective piston 43 applies a force to the force receiving surface 53 arranged at the bottom in Fig. 5, thereby causing a linear movement of the positioning part upwards in Fig. 5 until two contact surfaces 51 arranged at either side of a truncated corner opposite the active piston 43 contact two side surfaces 55 of the guide recess 25. Finally, in the state shown on the right in the lower row, the linear actuator 41 arranged at the right is activated and the respective piston 43 applies a force to the force receiving surface 53 arranged at the right in Fig. 5, thereby causing a linear movement of the positioning part to the left in Fig. 5 until two contact surfaces 51 arranged at either side of a truncated corner opposite the active piston 43 contact two side surfaces 55 of the guide recess 25.

[0049] It will be understood by the person skilled in the art that the terms left, right, top, bottom, upwards, downwards etc. used in the description only refer to the drawing plane and an actual movement direction in use may be chosen differently.

[0050] Fig. 6 shows in schematic views a second embodiment of a mounting device 5 similar to the one shown in Figs. 1 to 5, but having three insertion nozzles 15. The mounting device 5 comprises a positioning part 17, which is moveably arranged in a guide sleeve 23, wherein in the different views shown in Fig. 6, the positioning part 17 is moved into a central position and in three insertion positions, each associated with one of the three insertion nozzles 15. In case the nozzle arrangement 1 comprises three insertion nozzles 15, the guide recess 25 and the positioning part 17 each have a polygonal cross-section with at least three surfaces. In the embodiment shown, the cross-sections have geometric similarity and are each in the shape of a regular triangle. Hence, the positioning part 17 has three equilateral contact surfaces 51 , wherein adjacent contact surfaces 51 meet at a vertex 57. Similar, the guide recess 25 has three equilateral side surfaces 55, wherein adjacent side surfaces 55 meet at a vertex.

[0051 ] In the central position shown at the left in the upper row of Fig. 6, none of the linear actuators 41 is activated. In the state shown at the right in the upper row, the linear actuator 41 arranged at a top is activated and the piston 43 applies a force to the contact surface arranged at the top in Fig. 6, which functions as a force receiving surface 53, thereby causing a linear movement of the positioning part downwards in Fig. 6 until the two remaining contact surfaces 51 arranged at either side of the vertex opposite the active piston 43 contact two side surfaces 55 of the guide recess 25. In the state shown on the left in the lower row, the linear actuator 41 arranged at the left is activated and the respective piston 43 applies a force to the contact surface arranged at the left in Fig. 6, which functions as the force receiving surface 53, thereby causing a linear movement of the positioning part 17 upwards to the right in Fig. 6 until two contact surfaces 51 arranged at either side of a vertex 57 opposite the active piston 43 contact two side surfaces 55 of the guide recess 25. Finally, in the state shown on the right in the lower row, the linear actuator 41 arranged at the right is activated and the respective piston 43 applies a force to the contact surface arranged at the right in Fig. 6, which functions as the force receiving surface 53, thereby causing a linear movement of the positioning part 17 upwards to the left in Fig. 6 until two contact surfaces 51 arranged at either side of a vertex opposite the active piston 43 contact two side surfaces 55 of the guide recess 25. [0052] It will be understood that in the embodiment shown in Fig. 6, opposite of each pair of contact surfaces 51 abutting against side surfaces 55 in one of the three insertion positions, the remaining one of the three contact surfaces 51 is used as a force receiving surface 53 onto which a piston 43 of a linear actuator 41 can apply a force. [0053] Fig. 7 shows in six schematic views a mounting device 5 similar to the one shown in Figs. 1 to 5, but having five insertion nozzles 15. The mounting device 5 comprises a positioning part 17, which is moveably arranged in a guide sleeve 23, wherein in the different views shown in Fig. 7, the positioning part 17 is moved into a central position and in five insertion positions, each associated with one insertion nozzle 15. In case the nozzle arrangement comprises five insertion nozzles 15, the guide recess 25 and the positioning part 17 each have a polygonal cross-section with at least five surfaces. In the embodiment shown, the cross-sections have geometric similarity and are each in the shape of a regular pentagon. Hence, the positioning part 17 has five equilateral contact surfaces 51 , wherein adjacent contact surfaces 51 meet at a vertex 57. Similar, the guide recess 25 has five equilateral side surfaces 55, wherein adjacent side surfaces 55 meet at a vertex.

[0054] The mounting device 5 comprises five linear actuators 41 , each provided with one piston 43 adapted to push the positioning part 17 into one of the five insertion positions. In each insertion position, two contact surfaces 51 of the positioning part 17, which are arranged at either side of the vertex 57 opposite the active piston 43, contact two side surfaces 55 of the guide recess 25.

[0055] It will be understood by the person skilled in the art that in the embodiment shown in Fig. 7, opposite of each pair of contact surfaces 51 abutting against side surfaces 55 in one of the five insertion positions, a further one of the five contact surfaces 51 is arranged, which contact surface 51 can be used by a linear actuator 42 as a force receiving surface 53. [0056] In case the positioning part 17 and the guide recess 25 each have the shape of a regular polygon with N surfaces, wherein N is an uneven number, opposite each corner arranged between a pair of contact surfaces 51 abutting against side surfaces 55 in one of the insertion positions, a contact surface 51 is arranged, which can function as a force receiving surface. In case N is an even number, corner regions of the regular polygon oppose each other. Therefore, in one embodiment the corners between each pair of contact surfaces 51 abutting against side surfaces 55 in one of the insertion positions are truncated for forming force receiving surfaces 53 as shown in Fig. 5. [0057] According to an alternative embodiment shown in Figs. 8 and 9, the front nozzle support 16 is further provided with a force receiving part 59 with N force receiving surfaces 61 for receiving a force from an associated one of the N linear actuators 41 . In the embodiment shown in Figs. 8 and 9, six insertion nozzles 15 are provided. The positioning part 17 and the guiding recess 25 each have a cross-section in the shape of a regular hexagon. Hence, the positioning part 17 shown in Figs. 8 and 9 comprises six contact surfaces 51 arranged at angles of 120°.

[0058] The cross-section of the force receiving part 59 is also in the shape of a regular hexagon and the cross-section of the positioning part 17 have geometric similarity. The force receiving part 59 is arranged with an angular difference to the positioning part 17. The angular difference is 1807N, in particular 18076 = 30°, hence, the position of each corner of the positioning part 17 coincides with the position of a force receiving surface 61 of the force receiving part 59. As best seen in Fig. 8, the actuators 41 with pistons 43 are arranged in a holder 60 of the mounting device 5. [0059] It will be understood by the person skilled in the art that a similar mounting device as shown in Figs. 8 and 9 can be used for nozzle arrangements having eight or ten insertion nozzles.

[0060] Fig. 10 shows in eight schematic views a mounting device 5 similar to the one shown in Figs. 1 to 5, but having seven insertion nozzles 15. The mounting device 5 comprises a positioning part 17, which is moveably arranged in a guide sleeve 23, wherein in the different views shown in Fig. 10, the positioning part 17 is moved into a central position and in seven insertion positions, each associated with one insertion nozzle 15. In case the nozzle arrangement comprises seven insertion nozzles 15, the guide recess 25 and the positioning part 17 each have a polygonal cross-section with at least seven surfaces. In the embodiment shown, the cross-sections have geometric similarity and are each in the shape of a regular heptagon. Hence, the positioning part 17 has seven equilateral contact surfaces 51 , wherein adjacent contact surfaces 51 meet at a vertex 57. Similar, the guide recess 25 has seven equilateral side surfaces 55, wherein adjacent side surfaces 55 meet at a vertex.

[0061 ] The mounting device 5 comprises seven linear actuators 41 , each provided with one piston 43 adapted to push the positioning part 17 into one of the seven insertion positions. In each insertion position, two contact surfaces 51 of the positioning part 17, which are arranged at either side of the vertex 57 opposite the active piston 43 contact two side surfaces 55 of the guide recess 25. [0062] It will be understood by the person skilled in the art that in the embodiment shown in Fig. 10, as seven is an uneven number, opposite of each pair of contact surfaces 51 abutting against side surfaces 55 in one of the seven insertion positions, a further one of the seven contact surfaces 51 is arranged, which contact surface 51 can be used by an actuator 42 as a force receiving surface. Hence, no additional force receiving part is required.

[0063] In accordance with the application, the nozzle arrangement comprises N insertion nozzles 15, wherein a positioning part 17 is moveable in N directions until the positioning part 17 abuts against contact surfaces 51 of the guide sleeve 23. It will be understood by the person skilled in the art, that in the embodiments shown in Figs. 1 to 10, one or more additional nozzle could be provided. The additional nozzle is for example arranged in the center of the positioning part 17, wherein all actuators are simultaneously operated to move the positioning part 17 into the central position.

[0064] Fig. 1 1 shows an embodiment with eight nozzles comprising N insertion nozzles 15 as in claim 1 , in particular seven insertions nozzles 15, arranged at the positioning part 17 at corners of an imaginary heptagon and one additional nozzle 63 arranged at a center of the positioning part 17. The mounting device 5 shown in Fig. 1 1 is similar to the mounting device 5 shown in Fig. 10. The mounting device 5 comprises seven linear actuators 41 . As described above, each of the linear actuators 41 can be driven so that an associated piston 43 forces the positioning part 17 into a corner of the guide recess 25 arranged opposite the piston 43, wherein the positioning part 17 abuts with two contact surfaces 51 against side surfaces 55 of the guide recess 25 arranged at the corner. Further, as shown in the view on the left in the upper row of Fig. 1 1 , all actuators 41 can be simultaneously operated to move the positioning part 17 into the central position, thereby bringing the additional nozzle 63 into its use position. It should be noted that the term "additional nozzle" merely describes that the nozzle 63 differs from the insertion nozzles 15 in that in its use position, contact surfaces 51 of the positioning part 17 do not abut against two non-parallel side surfaces 55. Apart from this, the insertion nozzles 15 and the additional nozzle 63 can be designed and used in a similar or even identical manner, in particular the additional nozzle 63 can also be brought in its use position or insertion position and be used for an insertion of a weft thread. [0065] In case the linear actuators 41 each comprise a plurality of piston-cylinder actuators with pistons 43, for example three piston-cylinder actuators with pistons 43 as described with reference to Figs. 2 to 4, for each linear actuator 41 the stroke of the pistons 43 can be almost identical. In an alternative embodiment for each linear actuator 41 the stroke of one of the pistons 43 is limited, for example limited to almost half the stroke of the remaining pistons 43. By activating only the pistons 43 with a limited stroke, in particular by providing only compressed air to the pistons 43 with a limited stroke, the positioning part 17 can be reliably brought into its center position, wherein a misalignment of the positioning part 17 due to a force unbalance of the forces applied by the linear actuators 41 is avoided. By activating the remaining pistons 43 of one of the actuators 41 , in particular by providing compressed air to the remaining pistons 43 of one of the actuators 41 , the positioning part 17 can be brought against side surfaces 55 in order to bring one insertion nozzle 15 in its use position with respect to the insertion channel 1 1 .

[0066] According to an alternative not shown, in case a guide sleeve 23 with a guide recess 25 having a polygonal cross-section with N side surfaces 55, and a positioning part 17 having a polygonal cross-section with N contact surfaces 51 , are provided, N insertion nozzles 15 do not necessarily have to be provided, but also less than N insertion nozzles 15 can be provided. For example, in the embodiment of Fig. 8, instead of six insertion nozzles 15 for example only five of the six shown insertion nozzles 15 can be provided. [0067] It will be understood by the person skilled in the art, that although in all embodiments shown, flat contact surfaces 51 as well as flat side surfaces 55 are shown, in an alternative embodiment, at least one of the contact surfaces 51 and the side surfaces 55 is curved. In this case, the curvature of the at least one of the contact surfaces 51 and the side surfaces 55 is chosen such that neither the precise positioning nor the force receiving is impeded. It will also be understood by the person skilled in the art, that any kind of actuator that allows to bring the positioning part 17 in an use position can be used, and that the actuators are not limited to a linear actuator. Also an electric, hydraulic or any other type of actuator may be used as an alternative to a pneumatic actuator, which actuator can be controlled suitable.