Patent DE-19739411-A1 (DE)
Title: Weft band feed to warp knitter
Inventor: VETTERMANN FRANK DIPL ING
IPC: D04B23/12
Filed: 1997-08-28
Abstract: To feed a band of weft yarns (50), they are taken separately and in parallel to each other from a creel (4). They are gathered together in a band (5) at an intermediate store section (3) with a controlled drive to be held durably. They are taken from the store section (3) simultaneously, at intervals, by the weft yarn guide (22) of the yarn layer, and transferred to the transport chains (11,12). In an Independent claim the assembly has a creel (4) with bobbins (41) with weft yarns (50) to be drawn off as required. An intermediate store section (3) is between the exit of the creel and the weft yarn guide (22) of the yarn layer. The intermediate store is powered by a controlled motor (35), with a movement program which compensates for the difference between the intermittent weft yarn take-up at the yarn layer and a virtually continuous weft yarn take-off speed at the creel exit, by equalising the length change through the movement of the yarn layer from and to the fixed yarn guides (43). Preferred Features: The band of wefts (5) from the creel is moved to the side over the first transport chain (11) and over the layer, to a multiple yarn guide formed by a loose roller at the intermediate store, and then moved back to the guide of the layer. The movement range of the multiple guide is smaller than that of the yarn layer, and ends close to the second transport chain (12). The rhythm of the multiple guide movement differs from the yarn layer. As the weft layer moves towards the creel, the multiple guide has an initial temporary movement away from the creel and then moves with the layer and at a slower speed. In a second section, it reaches its end position and then moves in the opposite direction when the layer reaches the transport chain (11). The multiple guide (31) continues its movement, at a lower and constant speed, until the layer has reached its other end position near the transport chain (12). The take-off speed of the yarn band from the creel (4) is proportional to the working speed of the warp knitter. The movement of the multiple yarn guide is controlled to give additional compensation for the movement of the layer to and from the fixed guides (43) at the start of the intermediate store, during the delay and pause and acceleration phases of the layer, and the laying of the weft band along the transport chains (11,12). The creel is fitted with bobbins where the yarns are taken off at a tangent. The intermediate store, with its moving multiple yarn guide, is directly over the movement path of the weft layer, with the guide and layer moving on parallel paths. The multiple yarn guide, operated by a controlled motor (35), has the major portion of its movement path on the side towards the creel. The controlled motor for the multiple yarn guide, with position orientation, can be at the weft yarn layer. Two continuous belts (32), parallel to each other and parallel to the layer movement path, pass round fixed guide rollers (33,34), where one is the drive wheel (34) from a motor, controlled with position orientation. The multiple yarn guide is secured to one level of the belts. The weft layer movement is through a motor (254), controlled with position orientation, with a common control (6) for both motors (35,254) according to the machine speed. The movement speed of the weft band at the exit from the creel and from the weft guide (22) at the layer is monitored by sensors (7,8), with their measurement signals fed to the control to give a proportional yarn speed from the creel to the machine speed.