Cut presser machines are generally in tricot gauges from 12-24 and knit either staple spun yarns or textured yarns for blouses, dress-wear, baby-wear and shawls.
The fibre presser blade has sections which are cut away so that needle beards that correspond to these sections are not pressed at that cycle. Although needles can by this means hold their loops for a number of knitting cycles, their beards must be pressed at least once during the pattern repeat. All needle beards in the knitting width are eventually pressed by contact with the solid portions of the presser, as a result of the presser being shogged sideways by means of a push-rod and chain links in a similar manner to a guide bar.
For the production of simple shell-stitch fabrics, the presser is cut to the threading of the single guide bar whose total of adjacent threaded guides is the same as the total of adjacent empty guides.
For example, a 4 x 4 cut presser (Fig. 27.9) will press the four beards of the needles overlapped by the guide bar and will not press the four beards corresponding to the empty guides, so that these needles will hold their loops from a previous course or courses. If overlapped needles are not pressed, 'tuck stitches' will be produced, whereas drop stitches would occur if non-overlapped needle beards were pressed. It is thus necessary for the presser bar to be shogged sideways in unison with the guide bar.
In order to connect the sections of wales together, an atlas traverse lapping movement must be made across at least two more needle spaces than the number of adjacent empty guides, so that in the above example at least six needle spaces must be covered.
As held stitches are produced, the wales will contain different numbers of loops and some wales will contain successive loops that were actually knitted many cycles
Guide bar Cut presser
Guide bar Cut presser
apart in the sequence. Tension within the fabric produces distortion so that the wales lose their parallel alignment and a three-dimensional surface appearance is created (Fig. 27.10).
At the point where the atlas traverse changes direction, the absence of connecting underlaps on the far side of the traverse change produces unbalanced fabric tension that draws the two adjacent wales apart.
Most cut presser machines also have a plain presser bar that, when brought into action by means of a pattern chain, cancels out the effect of the cut presser, but this necessitates the use of an additional full-threaded guide bar.
Was this article helpful?