Weaving machine, yarn feeder and method for inserting a weft yarn

Abstract

A projectile-weaving machine is equipped with a weft yarn feeder having a stationary storage body for intermediately storing a yarn store consisting of windings, the weft feeder comprising a passive hollow balloon breaker functionally associated to a withdrawal rim of the storage body. In addition to the passive balloon breaker, several yarn control elements are separated in circumferential direction for being actively moved by a drive from an outer rest position into an inner operative position which without totally stopping withdrawn weft yarn are brought into a mechanical engagement on the weft yarn upstream from the withdrawal rim and starting with an end phase of an insertion on the weft yarn while the weft yarn is taken off from the yarn store over the withdrawal rim.

1 . Weaving machine having driven projectiles or rapiers as weft yarn insertion elements and at least one weft yarn feeder with a stationary storage body for intermediately storing a yarn store consisting of windings and further comprising a passive hollow balloon breaker which is functionally associated to the storage body having a front end withdrawal rim the diameter of which decreases in withdrawal direction of the weft yarn, wherein in addition to the passive balloon breaker several yarn control elements are provided at the weft yarn feeder which yarn control elements are distributed in circumferential direction with intermediate distances in between and which can be adjusted actively by at least one drive from an outer rest position in an end phase of an insertion into an inner operative position upstream from the withdrawal rim and into a mechanical engagement on the weft yarn which is taken off from the yarn store via the withdrawal rim without completely stopping the weft yarn. 
   
   
       2 . Weft yarn feeder for a weaving machine having driven projectiles or rapiers as weft yarn insertion elements, the weft yarn feeder comprising a stationary, drum-shaped storage body for intermediately storing a yarn store consisting of windings, out of which yarn store the weft yarn intermittently is taken off over head of a withdrawal rim at a front end of the storage body, the weft yarn feeder including a hollow passive balloon breaker functionally associated to the storage body, wherein in addition to the passive balloon breaker several yarn control elements are provided at the weft yarn feeder which yarn control elements are distributed in circumferential direction with intermediate distances in between and which can be adjusted actively by at least one drive from an outer rest position in an end phase of an insertion into an inner operative position upstream from the withdrawal rim and into a mechanical engagement on the weft yarn which is taken off from the yarn store via the withdrawal rim without completely stopping the weft yarn. 
   
   
       3 . Weft yarn feeder according to  claim 2 , wherein the yarn control elements are regularly distributed in circumferential direction in a common plane which is perpendicular to the axis of the storage body. 
   
   
       4 . Weft yarn feeder according to  claim 2 , wherein two to four yarn control elements are provided and that the intermediate distance between adjacent yarn control elements is larger in circumferential direction than the circumferential dimension of each yarn control element. 
   
   
       5 . Weft yarn feeder according to  claim 2 , wherein the yarn control elements point toward a region of the storage body upstream from the withdrawal rim, which region of the storage body extends continuously in circumferential direction, preferably to a region having a larger diameter than a region of the storage body provided for carrying the yarn store. 
   
   
       6 . Weft yarn feeder according to  claim 2 , wherein each yarn control element is a rigid pin which is movable substantially radially and the free end of which maintains in the operative position of the yarn control element a gap with storage body wider than the thickness of the weft yarn. 
   
   
       7 . Weft yarn feeder according to  claim 2 , wherein the yarn control element is connected to a linear drive such as a pneumatic cylinder or a solenoid and that the yarn control element is either driven by the linear drive in both movement directions or, in some cases, in one movement direction against spring force. 
   
   
       8 . Weft yarn feeder according to  claim 2 , wherein the yarn control elements and either a common drive for all yarn control elements or single discrete yarn control elements—drives are arranged at a ring body surrounding a front end of the storage body with radial distance. 
   
   
       9 . Weft yarn feeder according to  claim 2 , wherein a part of the yarn control element engaging in the operative position on the weft yarn is either rigid in circumferential direction or is flexible at least in circumferential direction. 
   
   
       10 . Weft yarn feeder according to  claim 8 , wherein the ring body is provided at a housing bracket of the weft yarn feeder for an adjustment substantially in the direction of the axis of the storage body, that the housing bracket comprises a linear adjusting mechanism for the ring body, and that the passive balloon breaker removably is secured to the ring body. 
   
   
       11 . Weft yarn feeder according to  claim 2 , wherein the yarn control element is either a brush having bristles or fingers pointing to the storage body which bristles or fingers preferably either are oriented substantially radially or are inclined in the direction of the rotation of the weft yarn during withdrawal, or is a brush having a layer consisting of foam material or felt. 
   
   
       12 . Weft yarn feeding device according to  claim 2 , wherein the yarn control element is a leaf spring, which, preferably, is bent in the direction of the rotation of the weft yarn during withdrawal, and that the drive is either a linear drive for linearly moving the leaf spring or is a pivot drive for pivoting the leaf spring. 
   
   
       13 . Weft yarn feeding device according to  claim 2 , wherein the yarn control element is either a pivot arm or a pivotable brush having fingers or bristles oriented toward the storage body, and that the drive is a pivot drive. 
   
   
       14 . A method for inserting a weft yarn into a weaving machine having driven projectiles or rapiers as insertion elements and comprising at least one weft yarn feeder having a stationary storage body for intermediately storing a yarn store consisting of windings, according to which method the weft yarn is taken off intermittently by the insertion elements from the yarn store over head and over a withdrawal rim of the storage body and through a passive hollow balloon breaker and is transported through the weaving shed of the weaving machine, wherein at least one yarn control element placed upstream from the withdrawal rim is moved at the end of an insertion from an outer rest position actively into an operative position maximally into contact with the storage body upstream from the withdrawal rim by a drive and without totally stopping the weft yarn, and that the yarn control element is returned actively into the rest position just shortly before the start of the subsequent insertion. 
   
   
       15 . Method according to  claim 14 , wherein in relation to an angle of rotation of 360° of a main shaft of the weaving machine, the yarn control element is brought into the operative position within about the last 30° to 70° of the insertion and up to about 5° to 10° or some milli-seconds prior to the start of the next insertion.