Support for main firing nozzle of air jet loom

Abstract

A support (A) for a main firing nozzle of an air jet loom, where the main firing nozzle comprises means for forming a compressed air jet and means for firing a weft yarn, and is equipped with brush means (1) for holding the weft yarn. The support (A) comprises a rear portion (A1) of the support and a front portion (A2) of the support, which are different and adjacent to each other at a connection surface of the support, at which a seat (4, 5) for accommodating one or more of the brush means (1) is provided.

Description

Technical Field

[0001] The invention relates to an improved support for the main ejecting nozzle of an air jet loom, said nozzle being equipped with a brush device for holding the weft yarn. Background Art

[0002] As is known, the weaving operation in an air jet loom consists of inserting a continuous weft yarn into a shed formed by a plurality of mutually parallel warp yarns divided into two groups according to different patterns, through a loom that controls the movement of the warp yarns to obtain a predetermined design of the fabric being formed.

[0003] The weft yarn can be inserted into the warp shed in different ways. In air-jet looms, the weft yarn is inserted into the shed using one or more compressed air main launching nozzles, each of which accommodates a weft yarn. When a specific weft yarn must be inserted into the shed, the corresponding main launching nozzle is supplied with compressed air to form an air jet that launches the weft yarn into the shed. Auxiliary nozzles, also supplied with compressed air, are then arranged at regular intervals along the warp shed to emit air jets that are appropriately directed to maintain the weft yarn along the reed channel and to the shed's outlet, on the side of the loom opposite to where it is inserted.

[0004] A typical problem with this configuration (particularly when using weft yarns containing elastic fibers) is maintaining the proper insertion of each weft yarn into its respective main nozzle in a stable manner during the weaving operation, i.e., preventing the weft yarn from exiting upstream of the nozzle when it is cut once fully inserted. During the insertion operation, the weft yarn is kept taut and correctly inserted into the main nozzle by the dynamic pressure of the compressed air jet; therefore, when the weft yarn is cut, at its inserted end, the previously tensioned textile fibers undergo elastic recovery, which can cause the free end of the newly cut weft yarn to move backward along the main nozzle until it exits the main nozzle. When the weft yarn exits its respective nozzle, it is obviously necessary to stop the loom and correctly reinsert the weft yarn into position, which inevitably reduces productivity, increases costs, and creates possible defects in the fabric.

[0005] EP-2226416 (2010) solves the above-mentioned problem in a particularly simple and effective manner by inserting a cylindrical ring equipped with bristles slightly converging in the direction of advance of the weft yarn (hereinafter also referred to as "brush" or "brush device") in each main nozzle downstream of the member forming the compressed air jet. In fact, during the insertion operation, the weft yarn flows freely through the brush device, but when the weft yarn is cut, any possible backward movement of its free end is immediately and effectively stopped by the brush device, and the weft yarn remains wrapped around the bristles of the brush device. EP-2778268 (2014), EP-3023525 (2016) and EP-3342910 (2018) disclose a number of different subsequent embodiments of the same inventive principle, which is disclosed in EP-2226416.

[0006] Figure 1a and 1b A nozzle assembly comprising four main launching nozzles according to the technical solution disclosed in EP-2226416 is shown. The nozzle assembly comprises a support A equipped with a plurality of cylindrical seats S with converging axes, one for each main nozzle controlling a corresponding weft yarn. A compressed air jet-forming component, including a corresponding ejector P, is inserted into each seat S at the weft yarn inlet side. This component is designed to guide the weft yarn internally and utilize its outer surface to adequately convey the compressed air flow, resulting in a compressed air jet properly directed around the weft yarn. A weft launching component is sealingly inserted into each seat S at the weft yarn outlet side of the support A. The weft launching component comprises a base C and a straight launching tube L that converges toward a head clamp M, which holds the end of the tube L in a stable position adjacent to the opening of the launching channel of the reed R. Compressed air is fed into the seats S via a dedicated duct formed within the support A, terminating in an opening O located in the side wall of the support A. Finally, a quick connector N is mounted in the opening O to allow the rapid connection of a flexible tube T supplying compressed air. The innovation disclosed in EP-2226416 consists precisely in inserting the brush device 1 described above into the base C of the launch tube L.

[0007] However, despite the efficiency and simplicity of the proposed solution, a significant technical drawback has emerged when using this device, namely the complexity of the cleaning operation of the brush device 1. In fact, such an operation is periodically required to maintain the brush function, which is gradually impaired by the entanglement of textile fibers separated from the weft yarn passing through the brush on the brush bristles. This entanglement of textile fibers actually hinders the free movement of the bristles, making the brush device less efficient and ultimately preventing the function of holding the weft yarn in the direction opposite to the normal insertion direction into the woven fabric.

[0008] Maintenance or replacement operations of the brush device may also be required when the operator may cause deformation of the bristles or breakage of the weft yarn by incorrectly extracting the weft yarn from the nozzle insertion side and thus cause the weft yarn to become entangled on the bristles.

[0009] In all of the aforementioned known devices, cleaning / replacing the brush assembly 1 requires opening the clamp M, removing the individual launch tubes L from the support A, and then opening the base C of each launch tube L so that the brush assembly 1 can be removed and cleaned / replaced. In EP-3342910, in particular, the components forming the compressed air jet also need to be disassembled beforehand, as the internal abutment structure of the launch tubes allows the brush assembly to be removed only from the rear side of the nozzle support. Consequently, in all of the aforementioned known solutions, this is a particularly time-consuming operation, requiring the operator to pay particular attention during reassembly to correctly align the diameters of the connecting components, insert the brush assembly into its seat without damaging the bristles, and correctly tighten the screws closing the clamp M and / or the screws securing the nozzle support to the loom sley. Finally, a final step of recalibration of the compressed air jet is usually necessary, as the reassembly operation does not guarantee the reestablishment of the identical geometrical positions of the various components of the main nozzle.

[0010] The aforementioned drawbacks, besides causing the brush cleaning operation to have a rather long processing time, necessarily require that this operation be performed by a specialized textile operator capable of correctly assembling the components and subsequently calibrating the compressed air jet. Summary of the Invention

[0011] Therefore, the technical problem solved by the present invention is to provide a support for a main nozzle of an air-jet loom, which allows simplifying the cleaning or replacement operation of the brush device of the main nozzle of the air-jet loom.

[0012] Within the scope of this technical problem, a first object of the present invention is to reduce the working time of maintenance operations (ie cleaning or replacement) of the brush device.

[0013] A second purpose of the invention is to prevent maintenance operations from modifying the geometrical arrangement of the components that determine the properties of the compressed air jet, making it possible to eliminate the step of calibrating said air jet after completion of the maintenance operation.

[0014] This problem is solved and these objects are achieved by a support for the main ejection nozzle of an air jet loom, the support being provided with a brush device for holding the weft yarn, the support having the characteristics defined in the main technical solution of the present invention. Other preferred features of the support for the main ejection nozzle are defined in the preferred technical solution. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Further features and advantages of the support for the main firing nozzle according to the invention will become more apparent from the following detailed description of a preferred embodiment thereof, given by way of non-limiting example only, and illustrated in the accompanying drawings, in which:

[0016] Figure 1a and 1b (Prior Art) A conventional main emission nozzle assembly provided with a brush holding device is shown in assembled and exploded views, respectively;

[0017] Figure 2 is a perspective view of a main firing nozzle assembly according to the present invention, the main firing nozzle assembly including a support for the main firing nozzle, the main firing nozzle assembly being mounted on an air jet loom and in a closed working configuration;

[0018] Figure 3 is similar to Figure 2 a view of the nozzle support in an open configuration for maintenance operations on the brush assembly;

[0019] Figure 4 are plan and cross-sectional views, on an enlarged scale, of a primary firing nozzle assembly alone, including a primary firing nozzle support according to the present invention, in a closed, working configuration;

[0020] Figure 5 is similar to Figure 4 , wherein the nozzle support is in an open configuration for maintenance operations of the brush device; and

[0021] Figure 6 is Figure 5 Perspective view of the main firing nozzle assembly in the open configuration. DETAILED DESCRIPTION

[0022] like Figure 2-6 As shown, in order to solve the above-mentioned problems with a structurally simple and effective solution, according to a first characteristic of the invention, the support for the main launching nozzle assembly is composed of two different parts. More precisely, the rear part A1 of the support includes the parts that form the air jet, while the front part A2 of the support includes the parts that launch the weft yarn, that is, the launching tube L and any accessories thereof. The two parts, the rear part A1 and the front part A2, are adjacent to each other at the connection surface and are independently fixed to a common base 3, which in turn is fixed to the loom sley B (by screws V1 and V2, respectively, of sufficient cross-section and easily accessible). Figure 6 ).

[0023] Furthermore, according to a second characteristic of the invention, the seat housing the brush device 1 is formed precisely at said connection surface between the rear portion A1 of the support and the front portion A2 of the support.

[0024] Thanks to this structure, all the brushes 1 of the main nozzle assembly can be directly and simultaneously accessed by simply loosening the rear portion A1 of the support from the fixing screws V1, that is, the portion connected to the compressed air supply tube T. In fact, since said tube T is generally of the flexible type, the rear portion A1 of the support, released from the base 3, can easily be disassembled from the front portion A2 of the support to the necessary extent to allow convenient access to or removal of the brushes 1, without having to disconnect or disassemble the components forming the compressed air jets, which are housed in the rear portion A1 of the support of the nozzle assembly.

[0025] As mentioned above, in practice, the seat for housing the brush device 1 is formed at the connecting surface of the two parts, the rear part A1 and the front part A2 of the support, so that when the rear part A1 of the support is detached from the front part A2 of the support, the brush 1 can be immediately accessed. Thanks to the fixing screws V2, the said front part of the support A2 remains integral with the base 3, without changing the alignment of the emission tube L relative to the said base 3 and the clamp M. In the embodiment shown, the seat for housing the brush device 1 is arranged between the two parts of the support A, and more precisely, as Figure 5 As better shown in FIG, for each brush device 1 in the rear part A1 of the support, a first cylindrical seat 4 is formed, in which the cylindrical ring of the brush device 1 is housed, while a second conical seat 5 is formed in the front part A2 of the support, in which the converging bristles of the brush device 1 are housed. In an alternative embodiment, both the first and second housing seats 4, 5 are formed in the front part A2 of the support. The embodiment shown is preferred because the bristles of the brush 1 become immediately visible when the rear part A1 of the support is disassembled ( Figure 3 ), so that the cleaning operation of the bristles can be performed even without removing the cylindrical rings of the brush device 1 from their respective cylindrical bases 4.

[0026] The pneumatic sealing of the mating surfaces of the rear part A1 of the support and the front part A2 of the support is obtained by simple contact between said surfaces, or by inserting between them a membrane acting as a gasket, or other type of airtight gasket, all of which is known per se.

[0027] Once the cleaning / replacement operation of the brush device 1 has been carried out, it is convenient to reposition the rear portion A1 of the support on the front portion A2 of the support, by means of suitable guide elements, so as to make it easier for the bristles of the brush 1 to be correctly inserted into their respective conical seats 5 without damaging them. In the embodiment shown, said guide elements consist of cylindrical pins 6 and corresponding holes 7 respectively formed in the two portions A1 and A2 of the support A, but it is obvious that any other centering means known per se could also be used.

[0028] From the foregoing description it should be clear how the present invention fully achieves all the intended objects. The provision of a support A consisting of two separate parts A1 and A2 (parts A1 and A2 adjacent to each other, independently fixed to a common base and therefore easily and quickly separable) and the provision of a seat for the brush device at the connecting surface between the two parts, the rear part A1 and the front part A2 of the support A, in fact allows very quick and easy access to the brush 1 without having to disassemble any other parts of the nozzle assembly, thus achieving the first object of the invention.

[0029] Furthermore, the fact that none of the other components of the nozzle assembly are disassembled during the removal of the rear portion A1 of the support ensures that the relative positions of these components (in particular the relative position of the injector P with respect to the seat S and the relative position of the launch tube L with respect to the front portion A2 of the support and the clamp M) remain unchanged, and therefore the hydrodynamic characteristics of the compressed air jet remain unchanged. This therefore allows the nozzle assembly to be reactivated in operation after a cleaning or replacement operation of the brush 1 without having to perform a new calibration of the compressed air jet, thus also achieving the second object of the invention.

[0030] However, it should be understood that the present invention should not be considered as limited to the specific arrangements shown above which are merely exemplary embodiments of the invention, but that different modifications are possible, all of which are within the capabilities of a person skilled in the art without thereby departing from the scope of protection of the invention itself, which is limited only by the appended claims.

Claims

1. A support member (A) for a main emission nozzle of an air jet loom, wherein: Each main emission nozzle comprises a component for forming a compressed air jet upstream and a component for emitting weft yarn downstream, and each main emission nozzle is also provided with a brush device (1) for holding the weft yarn, characterized in that the support (A) is composed of at least a rear part (A1) of the support and at least a front part (A2) of the support, the rear part and the front part are different and adjacent to each other at the connecting surface of the support (A), and a receiving seat (4, 5) for accommodating one or more of the brush devices (1) is provided at the connecting surface of the support (A).

2. The support for the main launching nozzle of an air jet loom according to claim 1, wherein the rear part (A1) of the support includes the component for forming the compressed air jet, and the front part (A2) of the support includes the component for launching the weft yarn.

3. A support for the main emission nozzle of an air-jet loom according to claim 2, wherein the rear part (A1) of the support and the front part (A2) of the support are independently fixed to the same base (3) by corresponding removable fixing devices (V1, V2), so that the rear part and the front part are adjacent to each other at the connecting surface of the support.

4. The support member for the main emission nozzle of the air jet loom according to claim 3, wherein: For each brush device (1), the housing seat of the brush device (1) comprises a first seat (4) for housing a ring equipped with bristles of the brush device (1) and a second seat (5) for housing the bristles of the brush device (1).

5. The support member for the main emission nozzle of the air jet loom according to claim 4, wherein: The first seat (4) is formed in the rear portion (A1) of the support, and the second seat (5) is formed in the front portion (A2) of the support.

6. The support member for the main emission nozzle of the air jet loom according to claim 4, wherein: The first seat (4) and the second seat (5) are both formed in the front portion (A2) of the support.

7. The support member for the main emission nozzle of an air jet loom according to any one of claims 4 to 6, wherein: The ring with bristles is cylindrical and the bristles are converging, and wherein the first seat has a cylindrical shape and the second seat has a conical shape.

8. The support member for the main emission nozzle of an air jet loom according to any one of claims 3 to 7, wherein: Guide elements are also provided to facilitate correct mutual positioning between the rear portion (A1) of the support and the front portion (A2) of the support when they are arranged adjacent to each other at the connecting surface of the support.

9. The support member for the main emitting nozzle of the air jet loom according to claim 8, wherein: The guide element is constituted by a pin (6) formed in one of the rear portion (A1) of the support and the front portion (A2) of the support, respectively, and a corresponding hole (7) in the other.

10. The support member for the main emission nozzle of an air jet loom according to any one of claims 3 to 7, wherein: A sealing gasket is also provided at the connection surface between the rear portion (A1) of the support and the front portion (A2) of the support.

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