A weft supply device for a loom, equipped with an independent optical unit integrated into a group of electromagnets that control the detachment of the weft thread.

Abstract

To provide a novel weft feeder for a loom, especially for air-jet and water-jet looms, which is equipped with an independent optical unit that is integrated into an electromagnet group of the weft feeder for controlling release of the weft in the loom.SOLUTION: A weft feeder for a loom comprises: a winding group (W) for winding a weft yarn on a weft feeder drum (D); an optical unit (P) comprising one or more optical sensors for monitoring the weft yarn wound on the drum (D) and the release of the weft yarn from the drum (D); an electromagnet group (E) controlling the movement of a stop pin (15) for preventing the release of the weft yarn from the drum (D) and enclosed within a cup-shaped shell (11) from which the stop pin protrudes so as to interfere with the drum (D); and a weft feeder processing board for controlling the logical function of the weft feeder.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a new loom weft supply device - especially for air jets and water jets - which, in addition to the normal functions already provided by known loom weft supply devices currently available, comprises an independent optical unit integrated into the electromagnet group of the weft supply device for controlling the loom shedding.

Background Art

[0002] As is well known, the weft supply device is a weft supply device between the loom and the yarn package. This supplies the loom with weft yarn by continuously winding it onto a cylindrical drum - clockwise or counterclockwise as much as possible at a constant speed according to the characteristics of the yarn - so as to generate a reserve portion of the weft yarn. Said reserve portion of the weft yarn is then taken out of the drum at a variable speed axially during the insertion operation of the weft yarn in the storage portion, thus not causing tension peaks in the weft yarn - which would impair the strength of the yarn itself and the quality of the fabric.

[0003] Weft supply devices have been used in textile factories for many years. In the course of their evolution, in addition to the above basic functions, additional control functions have been added to confirm the continuous presence of the weft yarn at specific key points of the weft supply device. Functions such as adjusting the accumulation amount of the weft yarn, adjusting the distance between individual coils as necessary, slowing down the discharge speed of the weft yarn so as to suppress the dynamic effects due to sudden withdrawal acceleration, measuring the length of the portion of the weft yarn pulled out by the insertion device, and finally, controlling the release of the weft yarn for insertion in the warp yarn storage portion at a preset length.

[0004] To properly perform the above functions, the weft supply device (Figure 1) is equipped with an optical unit P and an electromagnet group E (hereinafter also referred to as the "ELM group") mounted on the base body C of the weft supply device. The optical unit P includes one or more optical sensors and performs the function of monitoring the winding of the weft onto the drum D by the winding group W, which is integrated with the hollow shaft A of the weft supply device, through feedback control of the electric motor of the weft supply device. Therefore, the optical unit P also has the function of controlling the winding of new weft coils onto the drum D and counting the number of coils released from the drum D to the weft insertion device. The electromagnet group E controls the linear motion of the stop pin 15 between the forward position and the retracted position. In the forward position, the free end of the stop pin is inserted into a corresponding location provided on the fabric supply device drum D, preventing the weft from being detached from the drum, and in the retracted position, instead, the desired number of weft coils are released. Through the action of the electromagnet group E, the weft threads are actually drawn out of the loom in a predetermined number of coils, and this number is counted by the optical unit P.

[0005] A single optical unit contains multiple optical sensors with different functions. Specifically, these include: - Input optical sensor T: For each rotation of the weft yarn supply and winding group W, it confirms that the weft yarn is properly wound onto the drum and detects any breaks in the weft yarn. - Two exit optical sensors S and Z: Corresponding to the two rotational directions in which the yarn is wound onto the drum D by the winding group W, they detect the yarn coming out of the drum, count the number of coils drawn out of the loom, and determine the corresponding length of the drawn-out yarn. - Preliminary confirmation optical sensor R: This sensor detects the presence of coils at a preset height on the drum, thereby maintaining a constant maximum number of coils stored in the drum.

[0006] The number of optical sensors mounted in each optical unit varies depending on the type of function, and therefore affects the cost of the weft supply device. Basic optical units employ a minimal configuration suitable for the simplest operation, using only two sensors: an inlet sensor T and an outlet sensor S. On the other hand, the most advanced optical units are equipped with all four types of optical sensors described above; that is, in addition to sensors T and S, they also include a second outlet sensor Z and a preliminary verification optical sensor R.

[0007] For convenience and ease of assembly and connection, the optical unit P is usually assembled together with the electromagnet group E. However, this joint assembly of the optical unit and the ELM group has so far employed two substantially different embodiments. In the first embodiment, the optical unit P is actually freestanding and mounted on the outside of the electromagnet group E. On the other hand, in the second embodiment, the optical unit P is mounted inside the electromagnet group E, that is, enclosed within the same metal cup-shaped shell 11 that houses the ELM group, and is mechanically and electrically connected to the ELM group.

[0008] In the first embodiment, the electromagnet group E has appropriate locations for assembling and routing the cables of each optical sensor, and these locations are positioned in appropriate areas on the outer surface of the cup-shaped shell 11 of the ELM group, corresponding to the specific verification function of each optical sensor. In this first solution, the optical sensors are typically composed of traditional electronic components (so-called "through-holes," manually soldered and then encapsulated in a resin block). The advantage of this first embodiment is that, because the optical units are completely independent of the ELM group, associated maintenance, testing, and replacement are simple, quick, and economical operations. Furthermore, during manufacturing, these optical units can be tested individually before assembly into the ELM group. However, despite these advantages, the first embodiment described above has the disadvantage that the components used are large, requiring sufficient space for their installation and associated wiring. Therefore, it is extremely difficult to manufacture a weft feeder equipped with all four types of optical sensors described above, and this technical solution is usually limited to a weft feeder equipped only with the basic optical sensors T and S. Furthermore, mounting the optical unit on the outer surface of the cup-shaped shell 11 surrounding the ELM group creates textile drawbacks. This is because the optical unit impairs the uniformity of the outer surface of the cup-shaped shell of the ELM group, significantly increasing the likelihood of tangling within the weft supply device when the weft is released from the device.

[0009] In the second embodiment, the optical unit P is composed of miniaturized electronic components suitable for automated surface mounting (SMT) technology onto a printed circuit board (PCB). A suitable diaphragm and optical screen are added to the PCB and fixed, resin-encapsulated, and sealed within a cup-shaped shell 11 of the ELM group. The advantage of this second solution is, firstly, that all components of the optical unit P and the electromagnet group E are enclosed within the same cup-shaped shell 11. This results in a cleaner and more uniform outer surface of the shell 11, improving the operation of the weft feeder from a textile engineering perspective. Furthermore, the use of miniaturized components on the PCB and the insertion of the PCB into the cup-shaped shell 11 makes it possible to mount the four types of optical sensors described above (not only T and S, but also R and Z) through suitable windows formed in appropriate locations within the cup-shaped shell 11 without a significant increase in cost. The only drawback of this second solution is that, in stark contrast to the sole advantage of the first solution, the optical unit P is permanently incorporated into a cup-shaped shell and interconnected with the other components of the ELM group, making it impossible to test each component individually during manufacturing. If one of the optical sensors fails during use, the entire package, including the optical unit P, must be replaced. The entire assembly, including the electromagnet group E and the associated protective metal cup-shaped shell 11, must be replaced, which significantly impacts maintenance or replacement costs. EP-3620561 (in the name of the same applicant) discloses a weft feeder with an optical unit manufactured according to the second embodiment described above. [Overview of the project] [Problems that the invention aims to solve]

[0010] The technical problem that this invention solves is to manufacture a yarn feeding device that has the advantages of both of the two currently known forms of optical units, without the associated disadvantages. This optical unit is housed within the same cup-shaped shell that contains the electromagnet group, is independently testable during manufacturing, and is designed to allow maintenance and, in some cases, replacement without requiring the involvement of the electromagnet group.

[0011] In the context of this technical challenge, the first object of the present invention is to provide a completely self-contained optical unit that can be independently and easily removed from a cup-shaped housing shell, similar to the electromagnet group.

[0012] A second objective of the present invention is to reduce the number of wires coming out of the optical unit from two or more wires in conventional methods to just one wire.

[0013] Finally, a third objective of the present invention is to manufacture an optical unit that can optionally incorporate some or all of the four types of optical sensors into a single design without changing the structure of the optical unit, in order to expedite manufacturing, testing, maintenance, and replacement operations. [Means for solving the problem]

[0014] This problem is solved by a weft supply device for a loom that integrates an independent optical unit with a group of electromagnets that control the release of the weft, having the features defined in the independent claim 1, thereby achieving these objectives. Other preferred features of such a weft supply device are defined in the dependent claims. [Brief explanation of the drawing]

[0015] Further details of the features and advantages of the weft supply device according to the present invention, which integrates an independent optical unit with a group of electromagnets that control the release of the weft yarn, will become clearer from the detailed description of the following preferred embodiments. This description is presented only as a limited example and is shown in the accompanying drawings. [Figure 1] This is an axial cross-sectional view of a weft supply device equipped with an independent optical unit according to the present invention. [Figure 2] This is a perspective view of the independent optical unit before it is incorporated into the cup-shaped shell that houses the ELM group. [Figure 3] Figure 2 is an exploded view of the optical unit. [Figure 4] Figure 2 is a plan view showing the optical unit assembled and fixed into a cup-shaped shell that houses the ELM group. [Figure 5] This is a cross-sectional view of the optical unit in Figure 2 along line VV in Figure 4. [Figure 6] Figures 2-5 show a bottom perspective view of the cup-shaped shell housing the ELM group and optical unit. [Modes for carrying out the invention]

[0016] According to the present invention, the above problems are solved by a structurally innovative solution that allows for quick and easy assembly, testing, maintenance, and replacement. The independent optical unit consists of a rigid-flex printed circuit board housed in a closed, sealed protective box, from which only wiring extends for connection to the main weft supply processing board that controls the logical functions of the weft supply device. The protective box has dimensions and shape that allow for stable housing and fixing of the electromagnet group E to the bottom wall of a cup-shaped shell by removable fastening means. Other accessories necessary for the normal operation of the optical sensor that detects the weft are also pre-printed or inserted within the protective box. Thus, the optical unit P of the present invention is a completely self-contained group with no permanent mechanical or electrical connections whatsoever between the ELM group and the cup-shaped shell 11 that surrounds it. Therefore, the unit can be quickly and easily removed by simply disconnecting the end plugs of the wiring from the weft supply processing board, freeing the wiring from existing cable glands, and then loosening the aforementioned removable fastening means.

[0017] The innovative structure of the optical unit P of the present invention is clearly shown in Figure 2 and described in detail in the exploded view of Figure 3 and the cross-sectional views of Figures 4 and 5. Thus, the optical unit P includes a protective box 1 that defines its external size, consisting of a lower half box 1a and an upper half box 1b, which are interconnected by a suitable coupling and closing system to ensure complete dustproof and waterproof sealing. The protective box 1 is manufactured by molding a plastic material and houses all the components that contribute to the operation of the optical unit P. Inside the lower half box 1a is a rigid-flex PCB 2 to which four sets of light-emitting and light-receiving elements 3 are soldered (indicated in the drawings by reference number 3 with letter indexes (T, S, Z, R) corresponding to the type of sensor). The diaphragm 4d and optical channel 4c that support the optical elements 3 are necessary for the selection and shielding of the light beam and are shown in detail in Figure 5. These are formed by molding, preferably in the same process as the molding process of the protective box 1, and thus form part of the components of the protective box 1. The optical sensor of the optical unit P of the present invention, regardless of whether it is intended for control type T, S, Z, or R, consists of a pair of light-emitting and light-receiving elements 3, corresponding optical channels 4c and diaphragms 4d, and a light-shielding member 5 made of foam material that prevents light emission from diffusing in unwanted directions. The specific structure and operating details of the above optical sensor (characterized by SMD-type optical elements 3 whose optical axes are parallel to each other and perpendicular to the PCB surface 2) are disclosed in detail in the prior published patent EP-3620561 in the name of the same applicant. Its contents are referenced herein in full solely for the purpose of understanding the correct operation of the optical sensor, but such operation does not constitute part of the present invention.

[0018] The use of a rigid-flex PCB 2 (i.e., a PCT composed of multiple flat, rigid parts of the traditional type, connected by mechanically and elastically linked parts and, conversely, by highly flexible parts) allows for easy management of different inclinations between S-type, Z-type, and R-type optical sensors (all positioned on the same horizontal plane) and T-type optical sensors positioned on a plane strongly inclined to that common horizontal plane. PCB 2 actually has two independent rigid parts with different angular orientations, to which the optical elements 3 of the corresponding optical sensor are soldered. These rigid parts are connected by a flexible part 2f containing copper wiring that connects the SMD components mounted on the two rigid parts of PCB 2.

[0019] To provide an advantage over those disclosed in the aforementioned prior patents, in the optical unit P of the present invention, the optical channel 4c and aperture 4d are molded directly in the protective box 1. Specifically, the optical channel 4c is molded in the lower half-box 1a, and the aperture 4d is molded in the upper half-box 1b. This greatly simplifies both the manufacturing and assembly of the device. In fact, the same half-box 1a has a pre-formed, precise housing for the PCB 2, consisting of multiple components that work together to hold the PCB 2 in place, allowing the PCB 2 to be inserted into the half-box 1a quickly, with the optical components 3 aligned with the optical channel 4c and diaphragm 4d with the highest possible precision.

[0020] Once the alignment of the PCB 2 is completed, a light-shielding member 5, preferably made of a foamed material, is placed over each optical component 3. The light-shielding member 5 is necessary to prevent unwanted direct passage of light between the two light-emitting and light-receiving elements 3 of the same optical sensor - this direct passage may interfere with the correct operation of the optical sensor. Finally, the PCB 2 is connected to a wiring cable 6 having two male terminal connectors - one end is connected to a corresponding female connector 7 integrally formed on the PCB 2 where the entire copper wiring network of the PCB 2 converges, and the other end is connected to a special female connector formed on the weft supply processing substrate - and is electrically connected to a weft supply device processing substrate (not shown) that controls the logical functions of the weft supply device. The wiring cable 6 exits out through a hole 8 formed in the upper half-box 1b, and the hole 8 is closed by a normal rubber gasket 9 that elastically adheres to the edge of the hole 8 and the side surface of the wiring cable 6, thereby ensuring excellent sealing performance to prevent dust and liquid from entering the protective box 1. The hole for the passage of light radiation exchanged by the optical element 3 formed in the lower half-box 1a is closed and sealed in a known manner by a transparent glass disk 10 (see FIGS. 5 and 6).

[0021] After completing the arrangement of each member in the lower half-case 1a, the wiring cable 6 is connected to the same case, and at the same time, the upper half-case 1b is attached and sealed by an appropriate coupling and closing system to ensure the sealing performance to prevent the intrusion of dust and liquid, thereby forming the optical unit P of the invention. At this point, the protective case 1 is installed within a metal cup-shaped housing 11, the electromagnetic group E is housed within the housing, and it is fixed to the cup-shaped housing itself by removable fixing means 13 (such as screws or press studs) housed in through-holes 14 provided in the upper half-case 1b. According to a known method, the cup-shaped housing 11 is composed of one or more members and is closed by a lid 12 provided with a sealing gasket at the top. When assembling the protective case 1 within the cup-shaped housing 11, in order to make the assembly easy and rapid, the external features of its shape and size are designed such that an assembly that can be specially adapted within the cup-shaped housing 11 becomes possible. On the other hand, the glass disk 10 that partially protrudes from the bottom of the lower half-case 1a is arranged in holes corresponding to those formed in the cup-shaped housing 11 as shown in FIG. 5 (see FIG. 6).

[0022] From the above description, it is clear that the weft supply device of the present invention completely achieves the intended purpose. The optical unit P described above is actually completely independent mechanically and electrically from the housed metal cup-shaped housing 11 and the electromagnetic group E. Therefore, when the cable ground is arranged along the path of the wiring cable 6, it is possible to quickly remove the optical unit P as a whole simply by loosening the removable fixing means 13 and removing the wiring cable 6 from the weft supply device processing board. Furthermore, since the arrangement and wiring of the individual optical sensors 3 are completely independent of each other, depending on the target weft supply device and the purpose of use, the optical unit P can be equipped with the desired number and types of optical sensors 3 without requiring a design change.

[0023] However, it should be understood that the present invention is not limited to the specific configurations shown above, and these are merely examples. Different modifications are possible within the state of the art for those skilled in the art and do not deviate from the scope of protection of the present invention. The scope of protection of the present invention is defined only by the following claims. [Explanation of Symbols]

[0024] A Hollow Shaft C Base body D Drum E Electromagnet group (or ELM group) P Optical Unit R Preliminary confirmation optical sensor S: Indicator of the exit optical sensor T Inlet Optical Sensor W winding group Z is an indicator of the exit optical sensor. 1 protective box 1a Lower half box 1b Upper half box 2 Rigidflex PCBs Flexible part of PCB2 (2f) 3 Optical components 4c optical channel 4D diaphragm 5 Darkening material 6 Wiring Cables 7 Female connector 8 Cable 6 housing hole 9. Rubber gasket 10 Glass 11. Cup-shaped shell 12 Lid of cup-shaped shell 11 13 Removable fastening means 14 Hole for fixing means 13 15. Weft stop pin

Claims

1. A weft yarn supply device for a loom, The weft supply device comprises a drum, a winding group for winding the weft yarn onto the drum, an optical unit equipped with one or more optical sensors for monitoring the weft yarn wound on the drum and the weft yarn's detachment from the drum, a group of electromagnets surrounded inside a cup-shaped shell that controls the movement of a stop pin that prevents the weft yarn from detaching from the drum and protrudes so as to interfere with the drum, and a weft supply device processing board for controlling the logic functions of the weft supply device. The weft supply device for a loom is characterized in that the optical unit is housed in a protective box and electrically connected to the weft supply device processing board by direct wiring, and the protective box is housed inside the cup-shaped shell and is detachably fixed.

2. A weft supply device for a loom according to claim 1, wherein the function of the optical unit is independent and autonomous with respect to the function of the group of electromagnets surrounded inside the cup-shaped shell.

3. A weft supply device for a loom according to claim 1, wherein the protective box has an upper half box and a lower half box that are joined together.

4. A weft supply device for a loom according to claim 3, wherein the protective box is sealed to prevent dust and liquid from entering.

5. A weft supply device for a loom according to claim 1, wherein the optical unit has a printed circuit board to which the light-emitting and light-receiving elements of the light sensor are soldered.

6. A weft supply device for a loom according to claim 5, wherein the printed circuit board is a rigid-flex printed circuit board including two rigid parts to which light-emitting and light-receiving elements are soldered.

7. A weft supply device for a loom according to claim 5 or 6, further comprising a darkening member of a foamed material disposed on the light-emitting and light-receiving element.

8. A weft supply device for a loom according to claim 6, wherein the two rigid parts of the printed circuit board each have different inclinations and are connected by a flexible part of the printed circuit board which includes copper wires that interconnect components mounted on the two rigid parts.

9. A weft yarn supply device for a loom according to claim 5, wherein the wiring consists of a wiring cable that is electrically connected to the printed circuit board and the weft yarn supply device processing board via a plug connection.

10. A weft yarn supply device for a loom according to claim 9, further comprising a rubber gasket for sealing the outlet hole of the wiring cable coming out of the protective box.

11. A weft supply device for a loom according to claim 3, further comprising an optical channel and a diaphragm of the light sensor, which are integrally formed with the protective box.

12. A weft supply device for a loom according to claim 11, wherein the optical channel and the diaphragm are formed in the lower half box and the upper half box, respectively.

Images