WEFT FEEDER FOR WEAVING MACHINES HAVING AN ADJUSTABLE DIAMETER DRUM

Weft-feeder with yarn coil separation for weaving machines, of the type comprising an adjustable-diameter drum, comprising a few fixed sectors (B), for weft yarn winding; moving sectors (C), arranged within said drum, at each of said fixed sectors (B) and causing, with their own movement, the cyclical displacement of the weft yarn coils wound on said drum; adjustment means of the radial position of the fixed sectors (B) and of the moving sectors (C) within a pre-set range; and locking means of the fixed sectors (B) and of the moving sectors (C) which lock said fixed sectors (B) and said moving sectors (C) into any desired position within said range. The weft-feeder includes a kinematic system (2, 3, 4) mutually connecting the locking means (5) of said fixed sectors (B) and the locking means (M) of said moving sectors (C), said kinematic system being free to angular rotations in any plane passing through the axis (a) of the shaft (A) of the weft-feeder and torsionally and axially rigid respectively around and along said axis (a). The locking means (5) of said fixed sectors (B) are connected to a first locking/unlocking servo control comprising two electric motors (1) symmetrically arranged at the two side of the weft-feeder shaft (A).A second servo control simultaneously adjusts the radial position of the fixed sectors (B) and of the moving sectors (C) of the weft-feeder, thus modifying the diameter of said drum.A third servo control adjusts the position of an electromagnetic device (10) for stopping the weft yarn with respect to the position of an opposite fixed sector (B) of the weft-feeder.