The conventional V-bed machine relies on the two sets of needles, together with the takedown rollers, to hold the fabric down. The fabric is drawn downwards from the needle beds and passes between the grip formed by the roller and counter roller. The roller is composed of freely-turning sectional rollers on a common shaft. Each roller is pre-set spring-tensioned as the shaft turns under the influence of a racking pawl controlled by a lever and weight arrangement. Adjustable pressure rollers maintain the pressure grip.
The conventional mechanical takedown requires a continuous flow of knitted structure from the needles to the roller grip. The garment pieces must therefore be knitted in string formation, with each one joined to the next by a course knitted as a draw-thread that is removed later in order to separate the individual garment pieces.
The system operates most successfully on a fabric having a consistent knitting width, and a balanced course and knitted loop arrangement, both between the two needle beds and within each bed. As tension is exerted equally on all wales within the roller grip, those not gripped (at the selvedges if the fabric is being widened) will be untensioned, whilst held loops will receive excessive tension. Other wales, where more continuous knitting occurs, tend to receive insufficient tension. Thus, the mechanical arrangement tends to inhibit both shaping, and also types of designs that involve multiple tuck accumulation and holding loops over a number of courses.
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