Rieter

Piecing devices

Index

Installing piecing units at each spinning position is too complicated. Mobile piecing carriages mounted on rails attached to the machines are therefore used. The piecing carriages then have to perform the same, rather complicated, detailed operations as spinning personnel, but by mechanical means:

  • detecting ends down by rotating around the spindles
  • stopping at the right place
  • accurate positioning relative to the spindle
  • stopping the spindle
  • finding the yarn end
  • moving the ring traveler into the threading position
  • drawing the yarn into the ring traveler
  • releasing the spindle
  • spinning the yarn onto the fiber ribbon emerging from the front roller.

The whole process proceeds as follows (example: FIL-A-MAT by Zinser). During its inspection run along the ring spinning machine the FIL-A-MAT examines each individual spinning position photoelectrically for ends down. If a yarn is present it continues its run and examines the next spinning position. If it detects a yarn break, it stops in the working position in front of the spindle, extends the frame with the working elements and centers it precisely on the spindle bearing. The spindle is braked. Another working unit descends onto the ring rail and follows its motion during the subsequent operations.

The yarn end is then blown upward from the cop into the funnel-shaped opening of a suction tube. The yarn end can be at any point on the winding circumference. In the same way as the hand of a spinning operative, the yarn hook catches the yarn between the top of the tube and the yarn guide eyelet, lays it on the  spinning ring, and the piecer arm joins it to the fiber bundle on the delivery roller of the  drafting system. The remaining yarn residue is separated and extracted. A photocell monitors the success of the operation. The piecing process is repeated once if necessary, then the FIL-A-MAT leaves manual piecing to personnel.

Piecing devices can be used simultaneously for machine and production monitoring as well as roving stop motions, as was the case with Rieter‘s ROBOfil.

All these devices are no longer available for sale.