The first automatic V-bed machine to operate without cam boxes, the model TFK, was demonstrated by the Tsudakoma Corporation at the 1995 ITMA exhibition. The Asahi Chemical Industry Co. supported its earlier development. The model TFK has a working width of 122cm (48 in) in gauges 7,8,10 and 12, with a maximum variable speed of 1.2m/sec.
Individual linear electric motors drive the needles in their tricks (Fig. 19.13) The computer and control system regulate the linear motors to simulate the conventional actions of the knitting and transfer cams.
As each course of knitting takes place, the knitting curves or waves of the needles are clearly visible. The machine is fitted with 12 or 16 yarn carriers on four double-sided rails. Each yarn carrier is driven by its own quick-start step motor, via a
toothed belt. The yarn runs from the package to the yarn guide in a direct line via a yarn tensioner and knot catcher.
The machine computer synchronizes the needle clearing with the yarn carrier drive. Stitch length is programmed for each needle, with the linear motor allowing the needle to draw whatever loop length is required. Up to 30 different stitch lengths can be drawn across the knitting width. The stitch length ranges up to 8 mm in 0.1 mm graduations.
There is a moveable holding-down sinker between every two needles, each of which is driven by its own linear motor. They can be used for accumulated tuck stitch fabrics or, when knitting without the takedown system, needle bed racking by means of a step motor can take place over up to 7 needles in either direction.
Knitting begins with the start-up comb engaging the first course of the fabric, which is then taken over by the sub-assembly and final takedown mechanism. All have individually-programmed motor drives. When the garment component is completed, the yarn ends are clamped and severed by an automatic cutting device. The needles are then activated to press-off, without taking the yarn, and the component is ejected. Blanks or fully-fashioned garment pieces can be produced, including sequentially knitted fronts, backs and sleeves.
Various problems have been encountered, particularly due to the absence of brushes, latch openers or stitch pressers, which are usually attached to the cam-carriage. The greatest disadvantage is, however, the cost of the machine in comparison with conventional V-bed machines.
Was this article helpful?