Knitting Action of the Single Needle Bar Raschel Machine

Single Needle Bar Raschel Machine:
Raschel needles tend to have longer latches than weft knitting machine needles, to ensure that the wrapped yarns of the overlap goes onto and not below the open latch.There is a trick-plate extending the full width of the machine, whose walls preserve the needle spacing and whose verge provides an edge for a clean knock-over.

Basic Knitting Action of the Single Needle Bar Latch Needle Raschel Warp Knitting Machine:
The movement of the knitting elements of a Raschel machine is illustrated in the following figure.

Fig. Cross-section of a latch needle Raschel machine
a. Holding down: The guide bars are at the front of the machine, completing their underlap shog.The sinker bar moves forward to hold the fabric down whilst the needle bar starts to rise from knock-over.

b. Clearing: As the needle bar rises to its full height, the old overlaps slip down onto the stems after opening the latches, which are prevented from flicking closed by latch wires. The sinker bar then starts to withdraw to allow the guide bars to overlap.

c. Overlap: The guide bars swing to the back of the machine and then shog for the overlap.

d. Return swing: As the guide bars swing to the front, the warp threads wrap into the needle hooks.

e. Latch closing: The needle bar descends so that the old overlaps contact and close the latches, trapping the new overlaps inside.The sinker bar now starts to move forward.

f. Knocking-over and underlap: As the needle bar continues to descend, its head passes below the surface of the trick-plate, drawing the new overlap through the old overlap which is cast-off and as the sinkers advance over the trick-plate, the underlap shog of the guide bar is commenced.


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