Weft thread feeder with adjustable diameter drum for loom, comprising electromagnetic unit for controlling release of weft thread, equipped with quick release device for adjusting and fixing working position thereof
Patent Information
- Application Number
- CN202411934135.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Priority Date
- 2023-12-27
- Filing Date
- 2024-12-26
- Publication Date
- 2025-06-27
AI Technical Summary
In the existing weft feeders, the working position adjustment of the electromagnetic unit (ELM unit) is not accurate enough, resulting in uneven release of the weft yarn and affecting the quality of the fabric.
The adjustment and fixing device consisting of a fixed guide and a moving guide are adopted to achieve rapid and precise position adjustment and fixing of the ELM unit by tilting the flat contact surface and a quick release locking/unlocking device.
The high precision, repeatable position adjustment and fixation of the ELM unit is achieved, ensuring uniform release of the weft yarn and improving the quality of the fabric.
Smart Images
Figure CN120211012A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to a new weft feeder for a loom, in particular for air-jet looms and water-jet looms, which, in addition to the normal functions already provided by existing weft feeders of known types, includes an electromagnetic unit for controlling the release of the weft yarn, the electromagnetic unit being equipped with quick-release adjusting means for obtaining precise adjustment of its working position. Background Art
[0002] As is well known, a weft feeder is a weft feeding device inserted between a loom and a yarn reel, which feeds the weft yarn to the loom by continuously gathering the weft yarn in successive coils on a cylindrical drum at as constant a speed as possible, feeding in a clockwise or counterclockwise direction according to the thread characteristics, thereby forming a weft yarn reserve, and during the operation of inserting the weft yarn into the shed, the weft yarn reserve is subsequently withdrawn axially from the weft feeder drum at a variable speed without causing a peak in the tension in the weft yarn, which peak in tension would damage the integrity of the yarn itself and the quality of the fabric.
[0003] Weft feeders are devices that have been used in textile mills for many years. With the development of weft feeders over the years, in addition to the above basic functions, weft feeders have added additional control functions that allow checking for the constant presence of the weft yarn at certain critical points of the weft feeder, regulating the amount of weft yarn accumulated in the reserve and the distance between the individual coils, slowing down the output weft yarn in order to suppress the dynamic effects caused by sudden stretching accelerations, and ultimately controlling the release of the weft yarn in a predetermined length for insertion into the shed formed by the warp yarns.
[0004] In order to be able to correctly perform the above functions, the weft feeder ( Figure 1 ) is equipped with an optical unit and an electromagnetic unit E (hereinafter also referred to as the "ELM unit"). The optical unit includes one or more optical sensors and performs the function of monitoring the winding of the weft yarn on the drum D through a winding group W integral with the hollow shaft A of the weft feeder and by retroactively controlling the weft feeder motor, which controls the rotation of the hollow shaft A and thus the deposition of new turns of the weft yarn on the drum D, and performs the function of counting the number of coils released from the drum D to the weft insertion device. The ELM unit controls the linear movement of the weft yarn stop pin P between the advanced position and the retracted position, in which the free end of the weft yarn stop pin is inserted into a corresponding seat provided in the drum D, thereby preventing the weft yarn from being released from the weft feeder drum, while in the retracted position allowing the weft yarn to be released. Thanks to the combined action of the optical unit and the ELM unit, the weft yarn can thus be pulled out of the loom in a predetermined number of coils, the predetermined number of coils corresponding to the desired length of the weft yarn to be inserted into the shed.
[0005] For the correct operation of the optical unit and the ELM unit, the distance between the ELM unit and the drum D should be precisely determined to allow the optical unit sensor to correctly detect the passage of the weft yarn and to allow the stop pin P of the ELM unit to fully enter the corresponding seat of the drum D to hold the weft yarn coil on the drum D.
[0006] In a weft feeder with a drum of adjustable diameter according to the present invention, the working diameter of the drum D can be modified in each individual process to change the length of the weft yarn section fed to the loom. Then, it is necessary to adjust the position of the entire ELM unit directly mounted on the base body C of the weft feeder as quickly and stably as possible to track the new position of the drum D and then stably maintain a predetermined optimal working distance from that position.
[0007] Currently, the ELM unit slides along a pair of guiding means, which are respectively provided on the base body C of the weft feeder and in the ELM unit itself and have a radial direction with respect to the weft feeder drum D. Then, the ELM unit is fixed in the desired position by a pawl that slides within the guiding means provided in the base body. Via engagement with a screw passing through the ELM unit, in a direction parallel to the axis of the drum D, the pawl is actually fixed to the ELM unit, so it can be locked in place by acting on the screw to pull the pawl against the guiding means. In this way, the sliding of the ELM unit along the guiding means can be stopped at any desired position.
[0008] However, the ELM unit support and locking device described above shows two main drawbacks:
[0009] - The screw / pawl assembly has an inherent play that does not allow precise and repeatable adjustment of the ELM unit position. In particular, the ELM unit holding part freely swings around the screw / pawl assembly axis, which makes it difficult to maintain the correct parallelism of the lower plane of the ELM unit (where the optical sensor and the stop pin P are located) with the reference sector of the weft feeder drum D and the correct centering of the stop pin P with the corresponding seat provided on the drum D;
[0010] - Due to the looseness of the screw / pawl assembly, which necessarily occurs before the adjustment step of the ELM unit position, the ELM unit terminates at a position slightly different from the working position in the adjustment step. This means that in the step of tightening the pawl, a small displacement of the ELM unit with respect to the last set adjustment position is determined. For this reason, the adjustment and fixing process needs to be repeated to precisely determine the desired final position of the ELM unit. Summary of the Invention
[0011] Therefore, the technical problem solved by the present invention is to provide a weft feeder with an adjustable diameter drum, in which the working position of the ELM unit can be adjusted quickly, so that the ELM unit can be fixed at such a position with high precision and repeatability.
[0012] In the context of this technical problem, a first object of the present invention is to provide an ELM unit equipped with means for adjusting and fixing its working position, adapted to ensure a constant parallelism between the lower plane of the ELM unit and the reference sector of the weft feed drum D, and a correct centering of the stop pin P with the corresponding seat provided in the drum D.
[0013] A second object of the present invention is to provide an ELM unit in which the adjusting and fixing means can be operated quickly, preferably without using tools.
[0014] Finally, a third object of the present invention is to provide an ELM unit in which the working position of the ELM unit remains stable and unchanged even during the adjustment and fixing operations.
[0015] This problem is solved and these objects are achieved by a weft feeder for a loom with an adjustable diameter drum, which includes an electromagnetic unit of the weft feeder for controlling the release of the weft yarn and has the features defined in independent claim 1. Other preferred features of such a weft feeder are defined in the dependent claims. BRIEF DESCRIPTION OF THE DRAWINGS
[0016] However, further features and advantages of a weft feeder with an adjustable diameter drum, including an electromagnetic unit for controlling the release of the weft yarn, according to the present invention will become more apparent from the following detailed description of its preferred embodiments, which are given by way of non-limiting example and illustrated in the drawings, in which:
[0017] Figure 1 is an axial cross-sectional view of the weft feeder incorporating the electromagnetic unit of the present invention;
[0018] Figure 2 is a partial exploded perspective view showing the means for adjusting and fixing the working position of the ELM unit according to the present invention; and
[0019] Figure 3 is a view seen from the opposite direction of Figure 2 an exploded view of the ELM unit of DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0020] According to the present invention, in order to solve the problems emphasized above by means of a simple and quickly operable innovative solution, the ELM unit is fixed to the weft feeder base body C by means of an adjusting and fixing device, which is composed of a pair of fixed guides 1 arranged in the weft feeder base body C and a corresponding pair of movable guides 2 arranged in the ELM unit. The fixed guides 1 and the movable guides 2 are parallel and interconnected, and are preferably arranged symmetrically with respect to the axial plane of the weft feeder passing through and parallel to them. The longitudinal direction of the fixed guides 1 and the movable guides 2 is the radial direction with respect to the weft feeder drum D. In the adjusting step of the ELM unit position, the ELM unit should actually be able to move along this direction to adapt to the new diameter of the weft feeder drum D. The fixed guides 1 and / or the movable guides 2 are preferably made of a self-lubricating material.
[0021] According to the main features of the present invention, as Figure 2 and 3 clearly shown in, the sizes of the fixed guides 1 and the movable guides 2 are set such that when they are interconnected, the only contacting surfaces are only composed of the flat contacting surface 1a of the fixed guide 1 and the flat contacting surface 2a of the movable guide 2 respectively. At least one of the flat contacting surfaces 1a of the fixed guide 1 and the corresponding flat surface 2a of the movable guide 2, preferably both, are inclined with respect to the weft feeder axis. When the two flat contacting surfaces 1a are inclined, they are preferably arranged symmetrically with respect to the axial plane passing through and parallel to them. The lengths of the inclined flat surfaces 1a, 2a are sufficient to ensure the adjustable positioning of the ELM unit parallel to the longitudinal direction of the guides for each diameter of the weft feeder.
[0022] The fixed guides 1 are installed in their seats on the weft feeder base body C, so as to form an undercut groove between the fixed guides 1 or in the same base body C, and the retaining pawl 3 of the entire ELM unit slides in the undercut groove. Then, by means of a pull rod 4 of a predetermined length, the pawl 3 is fixed to a quick-release locking / unlocking device integral with the ELM unit body 5, and the length of the pull rod 4 is adjustable during the manufacturing or calibration process. The quick-release locking / unlocking device is preferably composed of a manually operated eccentric rod 6, which is hinged to the ELM unit body 5, and when the eccentric rod 6 rotates approximately 90°, the eccentric rod 6 is liable to give the pull rod 4 a wide enough movement to cause the locking / unlocking of the ELM unit. Due to this solution, the adjustment of the position of the ELM unit in the radial direction with respect to the weft feed drum can be carried out very quickly without the use of additional manual tools.
[0023] In fact, when the eccentric rod 6 is in the open position, the ELM unit moves freely along the guides 1, 2 until it is positioned at the desired height relative to the weft feeder drum. Conversely, when the eccentric rod is in the closed position, the ELM unit remains perfectly locked in the desired position. In addition, due to the specific mechanical solution used to construct the guides 1 and 2 (i.e., using contact walls composed of inclined flat surfaces 1a and 2a, which have a symmetric inclination relative to the axial plane of the weft feeder passing between them), the ELM unit locking / unlocking device has the characteristic of automatically centering the position of the ELM unit relative to the said axial plane. Therefore, it can ensure the constant repeatability of the position of the ELM unit relative to the base body C of the weft feeder during each subsequent adjustment of the position, while also eliminating any possible rotational vibration of the ELM unit around the axis of the locking / unlocking device composed of the pawl 3 and the pull rod 4.
[0024] Finally, the quick-release locking / unlocking device for the ELM unit according to the present invention also allows setting the desired preload force of the pull rod 4 during the manufacturing process by inserting suitable elastic means, so that even in the unlocked position, the ELM unit is held against the guide 1 by a sufficient preload force. In the illustrated embodiment, the elastic means is a small piece 7 made of rubber or other elastic material, which is inserted between the adjacent surfaces of the eccentric rod 6 and the body 5, as Figure 2 and 3 clearly shown. In particular, the preload force should be high enough to prevent the ELM unit from moving under the sole action of its own weight, and the preload force should be low enough to allow the movement of the ELM unit along the guide 1 when a suitable force is manually applied in this direction. This solution ensures higher accuracy of the position of the ELM unit because when the eccentric rod 6 is in the unlocked position, the ELM unit remains stationary at the periodically set adjustment position, and because when acting on the said eccentric rod 6 to lock the ELM unit, the position of the ELM unit does not change due to the pawl 3 abutting against the guide 1, precisely due to the preload force applied by the small piece 7. Therefore, the adjustment position and the locking position of the ELM unit perfectly coincide.
[0025] From the foregoing description, it is obvious that the present invention has fully achieved the intended purpose. In fact, the pair of guides with opposite inclined surfaces 1a and 2a allows keeping the lower plane of the ELM unit constantly parallel to the reference sector of the weft feeder drum D, and the stop pin P is correctly centered in the corresponding seat formed on the drum D.
[0026] In addition, due to the quick-release locking / unlocking device, the adjustment and fixing device of the present invention can be quickly manually operated, so there is no need to use tools.
[0027] Finally, due to the ability to set a desired preloading force for the locking / unlocking device when it is in the unlocked position, the adjusting and fixing device of the present invention also holds the ELM unit in a stable and unchanging operating position even during the adjusting and fixing steps.
[0028] However, it should be understood that the present invention should not be considered limited to the specific arrangements described above, which are merely exemplary embodiments of the present invention, but that different variations are possible without departing from the scope of protection of the present invention, all of which are within the capabilities of those skilled in the art, and the scope of protection of the present invention is defined only by the appended claims.
[0029] Reference signs:
[0030] A – hollow shaft
[0031] C – base body
[0032] D – drum
[0033] E – electromagnetic unit (or ELM unit)
[0034] P – stop pin
[0035] W – winding
[0036] 1 – fixed guide
[0037] 1a – inclined surface of the fixed guide
[0038] 2 – moving guide
[0039] 2a - inclined surface of the moving guide
[0040] 3 – pawl
[0041] 4 – adjustable pull rod
[0042] 5 – ELM unit body
[0043] 6 – eccentric rod
[0044] 7 – small piece made of rubber
Claims
1. A weft feeder with coil separation for a loom, comprising a winding group (W) which winds a weft thread on a drum (D) of the weft feeder; and an electromagnetic unit (E) which controls the movement of a stop pin (P) which prevents the weft thread from being released from the drum (D), wherein the electromagnetic unit (E) is movable in a radial direction relative to the axis of the weft feeder drum (D) along guiding means (1, 2) respectively arranged in a base body (C) of the weft feeder and in the electromagnetic unit (E), and wherein the guiding means (1, 2) are composed of a pair of fixed guides (1) and a pair of movable guides (2), the guiding means (1, 2) being parallel to the radial direction and coupled to each other, at least one of the fixed guides (1) and the movable guide (2) coupled thereto having flat contact surfaces (1a, 2a) inclined relative to the axis of the weft feeder, characterized in that It also includes a separate locking / unlocking means (3, 4), which has an axis parallel to the axis of the drum (D) and is used to stably fix the electromagnetic unit (E) in a predetermined position along the guiding means (1, 2), so that when the separate locking / unlocking means (3, 4) is tightened, the guiding means (1, 2) automatically causes the electromagnetic unit (E) to be centered relative to the axis of the weft feeder and prevents it from rotating around the axis of the locking / unlocking means (3, 4), wherein the separate locking / unlocking means (3, 4) includes a pawl (3) and a pull rod (4) connected to the pawl (3), the pawl being accommodated in an undercut groove, and the undercut groove being arranged between the pair of fixed guide members (1) or in the base body (C) of the weft feeder.
2. The weft feeder with stitch separation for a weaving machine according to claim 1, wherein the pull rod (4) is a screw rod engaged with the ratchet pawl (3).
3. A weft feeder with stitch separation for a loom as claimed in claim 1, wherein the pull rod (4) has a predetermined length and is connected to the pawl (3) at one end and to a quick release locking / unlocking device at its opposite end.
4. A weft feeder with stitch separation for a weaving machine according to claim 3, wherein the quick release locking / unlocking device comprises a manually operated eccentric lever (6) hinged to the body (5) of the electromagnetic unit.
5. A weft feeder with stitch separation for a weaving machine as claimed in claim 3 or 4, wherein the predetermined length of the pull rod (4) is adjustable during manufacturing or calibration.
6. A weft yarn feeder with stitch separation for a weaving machine according to claim 5, further comprising elastic means for applying a preload force on the pawl (3) in the unlocked position of the locking / unlocking device.
7. A weft feeder with loop separation for a loom as claimed in claim 6, wherein the elastic means comprises a small block (7) made of rubber or other elastic material, and the small block (7) is inserted between the adjacent surfaces of the eccentric rod (6) and the electromagnetic unit body (5).
8. A weft feeder with stitch separation for a loom as claimed in claim 6, wherein the preload force is high enough to prevent the electromagnet unit from moving under the sole action of its own weight, and wherein the preload force is low enough to allow the electromagnet unit to move along the paired fixed guides (1) when a suitable force is applied to the electromagnet unit in this direction.
9. A weft feeder with stitch separation for a weaving machine as claimed in any one of the preceding claims, wherein at least one between the pair of fixed guides (1) and the pair of moving guides (2) is made of a self-lubricating material.