The Whole Garment knitting technique

Shima Seiki launched their patented WholeGarment technique at ITMA'95 with two different V-bed models, each having unique features. These involve integrally and seamlessly knitting a complete tubular garment on a V-bed rib machine. A new feature of this technique is the ability to knit tubular rib with a high wale density and therefore improved extensibility and appearance.

WholeGarment knitting removes or reduces the need for subsequent making-up (and in some cases cutting) operations, consequently reducing the garment throughput time and work in progress. It also provides the potential for introducing novel styling features into knitwear garments.

The key concept of WholeGarment knitting is the facility to knit seamless body and sleeve tubes of virtually any type of plain, rib or purl construction, plus the ability to increase or decrease the sizes of the tubes and to move or merge them together as and when required during the garment knitting sequence.

The technique of knitting tubular courses of plain knit on a conventional V-bed flat machine is well understood and is used in the production of complete gloves on Shima Seiki automatic glove knitting machines.

In Fig. 19.9a, the running thread notations show the production of tubular plain in two traverses on a conventional V-bed flat machine. As the yarn passes across to the loops on the other needle bed, at each turn round of the cam-carriage a tubular course is knitted in plain fabric with the face loops on the outside and the reverse stitches on the inside of the tube. A number of tubular structures can be knitted at the same time (Fig. 19.9b); these can form the start of sleeves and a body.

Using loop transfer and other techniques to introduce or remove needles involved in knitting, it is possible to increase or decrease the size of the fabric tube, to move and merge it into other fabric tubes at a controlled rate, and to semi- or fully-close the tube either at the start or the end of the knitting sequence (Fig. 19.9b).

In order to integrally knit tubular-shaped garments, however, it is necessary to be able to knit tubular rib courses as and when required, particularly for the garment borders and the cuffs of sleeves.

The knitting of tubular courses of rib on a V-bed rib machine (Figures 19.10a and b) requires a carefully arranged sequence, particularly if a commercially acceptable wale density of rib is to be knitted. The problem is that in each traverse, front and back bed needles are required to knit the course of rib. The objective is for the front bed needles to eventually receive a complete traverse course of rib (face and reverse) loops and for the back bed to receive the return traverse course of rib loops.

The knitting of tubular rib on a conventional two needle bed flat machine does not, however, produce a rib that is very acceptable as far as extensibility and appearance is concerned because it is essentially knitted on only half the available needles (Fig. 19.11d).A course of 1 x 1 rib is first knitted using both needle beds (Fig. 19.11a) and is then transferred off onto one single bed (Fig. 19.11b).

Fig. 19.9 Tubular plain knitting on a flat machine.

Fig. 19.10 Tubular rib knitted on a carefully arranged needle sequence.

Fig. 19.10 Tubular rib knitted on a carefully arranged needle sequence.

Fig. 19.11 Half gauge tubular rib.

In order to receive transferred rib loops, complementary needles in the opposite bed must be empty of loops whilst other needles in that bed retain their loops from the same rib course of knitting. Additionally, in order to shape the garment by widening and narrowing or joining, tubular courses of rib are required to be transferred laterally onto other needles in the same bed.

The needles that are active therefore require careful selection so that the maximum possible number are involved in knitting. The linear distance between adjacent needle loops must be kept to a minimum, otherwise the extensibility of the rib wales will be seriously impaired.

The Shima solution to the dilemma is to provide machines with four sets of needles, two sets for each traverse row of the tubular rib, instead of the two needle beds available on conventional V-bed flat machines.

Shima introduced two models each with a different needle bed configuration:

1 The model SWG-X configuration uses four needle beds, each having an identical arrangement of needles and selection elements providing for knit, tuck, miss and rib loop transfer. Two additional needle beds are positioned at an angle of 5 to 10 degrees from the horizontal, in a flattened V-bed arrangement above the conventional V-beds. Each needle in an upper bed is exactly aligned above a needle in the corresponding bed beneath it and can thus replace its action if required. Only compound needles, with their slim profile, short knitting stroke and sliding action, can perform efficiently in such a confined space. (The Shima model SES 122 RT introduced in 1993 also has four beds but the upper two beds contain loop transfer points instead of needles)

2 The model SWG-y configuration has two needle beds in the normal V-bed arrangement. The needles, however, are in a twin gauge arrangement offset in pairs. Thus on a 5-gauge machine there are 5 pairs of needles (10 needles per inch of needle bed). There is a normal gauge distance between each pair of needles, and a fine gauge distance between each of the needles in a pair in each bed. Thus, on the V model, the pair of needles can function in the same manner as the two aligned needles in the upper and lower beds of the X model. The V model has a simpler configuration but, because of twin gauging, its finest gauge is 7 (14npi), whereas the X model is available in 7,10 and 12 gauges, and now has an additional loop presser bed.

19.17 The Shima model FIRST

The name FIRST is an acronym representing F (fully fashioning), I (intarsia), R and T (rib transfer) and S (sinker). It employs a slide compound needle that has a number of unique design features. Its hook-closing slide is split to form a pair of loop-holding pelerine points at its forward edge. When the slide is advanced beyond its normal hook-closing position, it transports the loop on its shoulder across the beds to engage with the opposite bed and thus transfer the loop (Fig. 19.12).

This transfer action does not require the assistance of a transfer spring on the needle. The needle is therefore centrally positioned in its trick, thus reducing yarn stress.

Conventional latch needles offset in grooves Slide needles centered in grooves

Fig. 19.12 Comparison of the new slide needle with the latch needle [Shima Seiki].

Conventional latch needles offset in grooves Slide needles centered in grooves

Fig. 19.12 Comparison of the new slide needle with the latch needle [Shima Seiki].

The outside shoulder of the slide is designed to retain a loop whilst another loop is inside the hook. Separate control of the two loops enables certain stitches to be knitted that were previously impracticable.

The slide needle has a thinner hook and a larger inside hook area, thus providing space for thicker yarns. The thinner hook is made possible because the hook does not receive the potentially damaging blows from a pivoting latch. Shima has three needle/needle bed arrangements designated small, medium and large. Small has fine needles and a small gap between the needle beds; medium has thicker needles but the same gap between the beds; and large has the same needles as medium but a larger gap between the beds.

In addition, there are four ranges of gauge based on needle pitch (the distance in millimetres between two adjacent needles in the same bed). '3.6' provides a gauge range up to E 7, '2.1' is the most popular giving a gauge range from E 6 to E 12, '1.8' provides a range up to E 14, and '1.4' provides the finest range up to E 18.

Three needle bed widths are available - 126 cm, 156 cm and 180 cm (50, 60 and 70 inches respectively). The short bed has 2 knitting cam systems; the other widths have 3 or 4.

Contra sinkers, moving in opposition to the needle movement, provide a knockover surface and reduce the needle movement. The resulting lower yarn tension enables different sizes of loops to be drawn.

Above the V-bed are two horizontally-mounted beds containing ancillary elements. The upper front bed carries loop transfer jacks and is split into two sections that can be racked outwards for widening and inwards for narrowing to take place simultaneously at the selvedges, without the need for empty traverses and separate left and right racking of the transfer jack bed.

The upper rear bed holds special loop pressers that press down on selected individual loops in the front or back needle beds. With this arrangement it is possible to press an inlay yarn behind a non-knitting needle.

Conventionally, yarn carriers are moved into position by the cam-carriage. After a course of intarsia or integral knitting, the carriage must use an empty course to move the yarn carrier out of the way in order to knit the next course. The Shima FIRST machine has a motor-driven yarn carrier system that automatically 'kicksback' the yarn carrier into its field of knitting and out of the way of the carriage, thus eliminating the need for empty traverses.

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