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CN-121992560-A - Weft feeder for a loom with spaced reels and adjustable diameter drums

CN121992560ACN 121992560 ACN121992560 ACN 121992560ACN-121992560-A

Abstract

Weft feeder for a weaving machine with spaced reels and adjustable diameter drums (D), wherein the drums (D) are formed by a plurality of fixed sectors (5), each provided with a respective support bar (5 g) housed in a respective seat formed in a static support disc (6) coaxial to a drive shaft (a) of the weft feeder, and wherein the spacing of the spaced reels on the drums (D) is caused by the oscillating and tilting movements of a plurality of movable sectors (7), each provided with a respective support bar (7 g), the support bars (7 g) being housed in a respective seat formed in a tilting support disc (8) eccentric and tilting with respect to the drive shaft (a) of the weft feeder, and wherein elastic elements are provided which exert a compressive force on the bars (5 g,7 g) to keep the fixed sectors (5) and the movable sectors (7) in a position stably engaged in their respective seat. The fixed sector (5) and the movable sector (7) are each provided with a single support bar (5 g,7 g), the support bars (5 g,7 g) being in the general shape of a trapezoidal rectangular prism, housed in respective seating grooves made up of cavities having a congruent trapezoidal shape, and the elastic elements exerting a compression force on the outsole of the support bar having the shape of a trapezoidal rectangular prism.

Inventors

  • Ricardo Comotto

Assignees

  • 罗伊有限公司

Dates

Publication Date
20260508
Application Date
20251107
Priority Date
20241107

Claims (11)

  1. 1. Weft feeder for a weaving machine with spaced reels and adjustable diameter drums (D), wherein the drums (D) are formed by a plurality of fixed sectors (5), each of which is provided with a respective support rod (5 g), the support rods (5 g) being housed in respective seats formed in a static support disc (6) coaxial with the drive shaft (a) of the weft feeder, and wherein the spacing of the spaced reels on the drums (D) is caused by the oscillating and tilting movements of a plurality of movable sectors (7), each movable sector being provided with a respective support rod (7 g), the support rods (7 g) being housed in respective seats formed in a tilting support disc (8), being eccentric and tilting with respect to the drive shaft (a) of the weft feeder, and wherein elastic elements are provided which exert a compressive force on the rods (5 g, 7 g) to keep the fixed sectors (5) and the movable sectors (7) in their respective seats stably engaged position, characterized in that the fixed sectors (5) and the movable sectors (7) are housed in respective seats, the movable sectors (7) have a substantially right-angled cavity, the right-angled cavity, and the right-angled cavity, of which is defined by the respective sector (7 g) and the right-angled cavity, the elastic member applies a compressive force to the outsole of the support rod having the general shape of a trapezoid-shaped right angle prism.
  2. 2. Weft feeder for a loom according to claim 1, wherein said support bars (5 g, 7 g) of the fixed sector (5) and of the movable sector (7) are in the shape of isosceles trapezoid right prisms.
  3. 3. Weft feeder for weaving looms according to claim 1 or 2, wherein the small bottom of the supporting bar (5 g, 7 g) in the shape of a trapezoidal right-angled prism comprises elements for guiding its longitudinal movement and adjusting its position in the respective seat groove.
  4. 4. A weft feeder for a loom according to any one of claims 1 to 3, wherein the compression force: a. Is greater than the minimum clamping force required to keep the adjustment position of the support bar (5 g, 7 g) unchanged during normal operation of the weft feeder, and B. less than the maximum clamping force that still allows the support rods (5 g, 7 g) to slide in their respective seat grooves during the operation of adjusting the position of the fixed sector (5) and the movable sector (7).
  5. 5. Weft feeder for a weaving machine according to any one of claims 1 to 4, further comprising a quick-tensioning fastener bistable between a locked position and an unlocked position, which varies the compression force exerted by the elastic element on the support bar (5 g, 7 g).
  6. 6. Weft feeder for a loom according to claim 5, wherein the compression force after the change is: a. In the locked position, greater than the minimum clamping force required to keep the adjusted position of the support bar (5 g, 7 g) unchanged in each operating condition of the weft feeder, and B. In the unlocked position, less than the maximum clamping force that still allows the support bar (5 g, 7 g) to slide in its respective seat during the operation of adjusting the position of the fixed and movable sectors (5, 7).
  7. 7. Weft feeder for weaving machines according to any one of the preceding claims, wherein the elastic element comprises a wave or belleville spring (10, 13) acting on the support bars (5 g, 7 g) of the fixed sector (5) and of the movable sector (7) under a specific preload imposed by the closing ring (11, 14).
  8. 8. Weft feeder for a loom according to claim 7, further comprising a flat and rigid compression bar ring (9, 12) interposed between said elastic element (10, 13) and said support bars (5 g, 7 g) of the fixed sector (5) and of the movable sector (7).
  9. 9. Weft feeder for weaving looms according to claim 5 or 6, wherein the quick-tensioning fastener comprises a locking ring (23) interposed between the elastic element (10, 13) and the closing ring (11, 14) and free to rotate between them, the opposite contact surfaces of the locking ring (23) and the closing ring (11, 14) being undulating contact surfaces (24) cooperating for changing the axial position of the locking ring (23) between a position distant from the closing ring and a position close to the closing ring (11, 14) during rotation of the locking ring, thereby changing the preload on the elastic element (10, 13).
  10. 10. Weft feeder for a loom according to claim 9, wherein said locking ring (23) is provided with a protrusion (25) determining its extreme position with respect to the rotation of a corresponding end stop (28) formed in said closing ring (11, 14).
  11. 11. Weft feeder for a loom according to claim 10, wherein said protrusions (25) are provided with grip holes (26) for engaging a control lever.

Description

Weft feeder for a loom with spaced reels and adjustable diameter drums Technical Field The present invention relates to a new type of weft feeder for looms with spaced reels, in particular for air-jet looms and water-jet looms, which allows a particularly rapid adjustment of the drum diameter, in addition to the normal functions already provided by weft feeders of the known type currently available. Background As is known, a weft feeder (feeder) is a weft feeder device, interposed between the loom and the reel, which forms a weft reserve by continuously accumulating weft yarn in the form of successive, spaced reels on a cylindrical drum at a speed as constant as possible (in a clockwise or counter-clockwise direction according to the thread characteristics). Subsequently, during the weft thread insertion in the shed, the weft thread is extracted in the axial direction from the drum of the weft feeder at a variable speed, avoiding tension peaks in the weft thread that would damage the integrity of the thread itself and the quality of the fabric. Weft feeders are devices commonly used for many years by textile mills, which, in addition to the basic functions described above, add additional control functions that allow checking the persistence of weft thread at the critical points of the weft feeder, adjusting the amount of weft thread accumulated in the reserve and the mutual distance or pitch between the individual reels, braking the output weft thread to control the dynamic effects caused by the sudden extraction acceleration, measuring the length of the weft thread segment extracted by the introduction device, and eventually stopping weft thread extraction immediately after a predetermined length has been provided. The amount of weft yarn accumulated in the reserve obviously depends on the diameter of the drum of the weft feeder around which the reserve is wound, and on the number of coils that can be simultaneously accommodated on said drum. In order to increase the adjustment range of the individual weft feeders, thereby making them suitable for air-jet looms and water-jet looms with a large difference in height, the possibility of varying the diameter of the drum is introduced in addition to the possibility of varying the number of coils by varying the pitch between successive coils. In fact, the variation of the diameter of the drum allows fine-tuning of the length of the weft thread introduced, considering that this length corresponds to an integer number of coils, since there is only one stopping point for the weft thread leaving the weft feeder drum. For this purpose, the drum is usually formed by a plurality (typically four) of fixed sectors, each of which is fixed independently to the weft feeder body. In the case of an adjustable diameter drum, the fixing sector is fixed to the weft feeder body in an adjustable radial position and then clamped in the desired position by means of a locking screw. In order to automate and speed up this adjustment process, WO2015/169612 discloses a weft feeder provided with an irreversible gear system operated by servo control. The system allows to adjust the radial position of the three adjustable sectors of the weft feeder simultaneously, while ensuring that the three adjustable sectors are locked in the desired adjustment position without the use of locking screws, thanks to the irreversibility of the gear system. Each adjustable sector is provided with two support bars, parallel or slightly converging, and the gear system cooperates with only one of said bars, which is therefore provided with a rack portion, while the other bar slides in the corresponding guide, to increase the stability of the adjustable sector. The fourth sector has a constant position, since the presence of a weft thread is optically detected thereon, and therefore, for a simpler construction, it is decided to always keep this sector at a fixed distance from and parallel to the weft feeder arm, on which arm an optical sensor for detecting a weft thread is mounted. In the type provided with means for spacing the individual coils wound on the drum at a predetermined pitch, commonly known as weft feeders with spaced coils, there are also provided a corresponding number of movable sectors mounted on a fixed inclined flange, which in turn is supported by the external surface of a bushing keyed to the eccentric portion of the weft feeder shaft, through the interposition of ball bearings, said bushing being further provided with an external cylindrical surface inclined by a few degrees with respect to the drum surface. Due to this arrangement, during rotation of the weft feeder shaft, the inclined bushings rotate integrally with said shaft and with the bearing inner race, resulting in a combined periodic oscillation of the bearing itself and thus of the inclined flange integral with the bearing outer race. The oscillations of the tilting flange are transmitted to the movable sectors, in particular t