Knitting machines

The knitting machine (knitting frame, knitting loom) is used to produce knit fabrics on a fixed bed of spring-bearded needles. Knitting machines can be hand powered or motor assisted. Pattern stitches can be selected by hand manipulation of the needles, or with push-buttons and dials, or electronic pattern reading devices and computers.

The knitting industry as a whole can be divided into four manufacturing sectors, these are: fully fashioned, flat knitting, circular knitting and warp knitting.

Fully Fashioned Machines.Traditionally these machines produce plain “classical” styled wool knitwear by producing panels that are shaped to style “Fashioned” during knitting. After knitting the front, back and sleeve panels are linked to form the garment.

Fully Fashioned machines are sometimes referred to as straight-bar, flat bar, “Cottons Patent” or “Cotton machines” due to patents that were given to William Cotton way back in the mid 1800’s.

Bearded needles are set into a straight-bar in a long row and the entire bar is reciprocated by rotary cams, which cause the knitting action. The knitting yarn is laid across the width of the needles, which is simultaneously followed by the sinkers/dividers, which push the yarn firmly against the stem of the needles ready for loop formation.

Generally Fully Fashioned machines only have one set of needles and therefore can only produce plain knit fabric; the welts/cuffs are produced on special ribbing knitting machines. The ribs are held on “running-on” bars and are either transferred on to the Fully Fashioned machine by hand or automatically depending on the age of the machine.

The patterning capability of Fully Fashioned machines is limited to plain knit fully fashioned panels.

The gentle knitting action of these machines allows the use of delicate fine woolen spun yarns and also enables the machines to run faster where possible giving good knitting efficiency.

Flat Knitting Machines Sometimes referred to as “Flatbeds” or “V-beds” due to the nature and arrangements of the knitting beds where two opposing needle beds are positioned so that the upper ends form an inverted “V”. Needles slide up and down the beds in slots known as “tricks”.

The carriage or “cam box” traverses across the needle beds and selects needles to be knitted as it reciprocates side to side. The carriage effectively raises and lowers the needles on both beds simultaneously as it passes over them, depending on the desired pattern.

What makes these machines so versatile, apart from the virtually unlimited patterning capacity, is that the stitches can be passed from one bed to the other and the beds can be moved linearly in relation to each other. This not only allows panels to be shaped, but it also opens up extensive patterning possibilities using stitch transfer. Furthermore parts of the garment that are normally added during make-up such as pockets, collars, trims, V-necks, etc, can now all be knit as an integral part of the panel.

Advanced technology has now made it possible for complete garments to be knitted on the machine, without the need for any making-up. The technique of complete garment knitting is done in one of two ways; either using an adapted version of a V-bed, or by using a special machine that has four needle beds.

Circular Knitting Machines.There are many types of circular knitting machines which produce long lengths of tubular fabric and quite often they are manufactured with very specific end uses in mind.

Single Jersey Machines

Single Jersey machines are equipped with a single “cylinder”, about 30 inch diameter, of needles that produce plain fabrics (single thickness).

Wool production on single jersey machines tends to be limited to 20 gauge or coarser, as these gauges can use two-fold wool yarns which will spirality-free fabrics. An additional feature of wool single jersey fabrics is that the fabric edges tend to curl inwards. This is not a problem whilst the fabric is in tubular form but once cut open can become so if the fabric is not finished correctly.

Double Jersey Machines Double jersey machines are single jersey machines with a “dial” which houses an extra set of needles positioned horizontally adjacent to the vertical cylinder needles. This extra set of needles allows the production of fabrics that are twice as thick as single jersey fabrics.

Typical examples include interlock based structures for underwear/base layer garments and 1 x 1 rib fabrics for leggings and outerwear products. Much finer yarns can be used as singles yarns do not present a problem for double jersey knitted fabrics as the “double layer” construction works to cancel out the residual torque between the face and reverse sides, the net effect being no spirality.

here are domestic and industrial models, with either flat or circular beds that produce rectangular or tubular fabrics. Double bed machines have two flat beds facing each other, in order to produce purl and plain rib fabrics plus a variety of multi patterns. Ribbing attachments can be added to single bed machines to achieve a similar result.

Late 20th Century domestic/studio/home models typically use up to 200 latch hooks needles to hold the stitches in a standard or bulky size needle. A carriage or cam box is passed across the bed of needles causing the needle movements required to produce each next stitch. By various selection methods, e.g. particular needles can be caused to travel by alternate pathways through the cam box. Thus needles will knit or not, and the unknitted yarn portions will lie under (slip stitch) or over the needle or be held in the needle hook (tuck stitch). Needles can be placed in holding position to allow short row shaping. Most of these machines can knit two colour "fair isle" patterns automatically, and have machine stitch patterning features such as plating and knitweaving. Plating refers to knitting with two strands of yarn that are held in such a way that one is in front of the other. Plated effects can be particularly striking in a ribbed fabric. Knitweaving refers to a technique in which a separate piece of yarn, often heavier than the knitted fabric, is carried along and caught between stitches to produce an effect like weaving. With knitwoven fabric, the purl side (usually the wrong side) is the right side of the fabric. With the addition of a lace carriage, stitches can be transferred from one needle to the next. The yarn passes through a tensioning mechanism and down through the knit carriage, which feeds the yarn to the needles as they knit.

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