Knitting technology, Third Edition

23
Basic warp knitting principles
23.1
Construction of warp knitted fabrics
In a warp knitted structure, all ends supplied from the same warp sheet normally
have identical lapping movements because each is lapped by a guide attached to
the same guide bar (Fig. 23.1). Beams (Fig. 23.2) supply the warp sheets in parallel
form to the guide bars, whose pattern control determines the timing and configu-
ration of the lapping movements in the form of overlaps and underlaps. The needles
intermesh the new overlaps through the old overlaps to form the intermeshed loop
structure.
Fig. 23.1
Guide bar lapping movement.

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Basic warp knitting principles
287
23.2
The warp beams
To ensure uniform conditions of warp feed and tension, the yarn ends are supplied
from flanged beams attached to shafts that turn to unwind the warp sheet in 
parallel formation. For convenience of handling, a number of beams may be
attached to a beam shaft to achieve the full width of the warp sheet; for example, a
warp sheet 84 inches (213 cm) wide might be supplied from a full-width beam, from
two beams each 42 inches (106 cm) wide, or from four beams each 21 inches (53 cm)
wide.
23.3
The guide bar
Each guide bar is normally supplied with a warp sheet from its own beam shaft 
to suit its requirements of threading and rate of warp feed for its particular lapping
movement. Occasionally, two partly-threaded guide bars may be supplied from 
the same fully-threaded beam, provided they make lapping movements of the same
extent to each other whilst moving in opposite directions. The minimum number 
of guide bars and warp sheets for commercially acceptable structures is usually 
two.
23.4
The guides
Warp guides are thin metal plates drilled with a hole in their lower end through
which a warp end may be threaded if required. They are held together at their upper
end as a single unit in a metal lead and are spaced to the same gauge as the needles.
Fig. 23.2
Tricot machine HKS 2-3 [Karl Mayer].

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288
Knitting technology
The leads are attached to a guide bar so that the guides hang down from it, with
each one occupying a position, when at rest, midway between two adjacent needles.
In this position, the warp thread cannot be received by the needles and it will
merely produce a straight vertical float. The needles only receive the warp thread
in their hooks if the guide bar overlaps across their hooks
,
or across their backs
when the guide bar underlaps. All guides in a conventional guide bar produce an
identical lapping movement at the same time and therefore have identical require-
ments of warp tension and rate of feed, although the threads may differ in colour
or composition from each other.