Taking a 400 hook machine, the commonest size used for cotton weaving,
we find a row of 8 needles or lances E of thin wire, arranged
horizontally; at the left hand we see each of these attached to a
spring in the spring box A, the other end projecting about 3/8-inch
through a needle board B. Each lance regulates a vertical wire hooked
top and bottom, and shown with each upper hook standing over its
respective griffe or knife C. These griffes, eight in number, are
lifted simultaneously through being connected together at the ends.
The lower end of the hook rests on a wire grid J, slotted so as to
allow the lower end of the hooks--to which are attached the neck cords
F--to pass through. A bottom board below the bend is used for those
machines which have no wire grid. To these neck cords is attached the
harness--_i.e._, linen threads or leashes, some seven feet in length,
carrying a brass mail-eye H, through which the end of warp is drawn.
Just above the mail-eye the harness passes through a cumber board C,
for the purpose of keeping in proper order and regulating the number of
leashes per inch. At the bottom of each leash is fixed a metal weight,
called a lingo, intended to pull the leash down after having been
raised to form the shed.
The method of raising the ends is as follows:--A square cylinder is
placed at D, and makes a quarter of a revolution at each pick. This
cylinder carries a set of cards (N^1, N^2, N^3), sheets of cardboard
perforated in places. Supposing a 400 (408) machine is referred to,
each card has space for 408 perforations, the holes corresponding in
position with the ends of the 408 needles projecting through the needle
board. A hole indicates a lift.
THE CARDS.
The cards are only perforated by groups of holes distributed
incidentally, and where no perforation is made the needles at that
point are pushed back 3/8-inch by the cylinder. This is sufficient to
remove the tops of the corresponding hooks attached to these needles
from their position over the griffe; thus, when this knife or griffe
is lifted it does not actuate these hooks, but only those which were
not pushed back by the cylinder and card. Suppose, for instance, one
hook out of four had to be lifted, then 102 perforations would be made
in the card, and 306 hooks would thus be pressed back, whilst 102 only
would be lifted. The holes in these cards can be cut in any order, and
as one card acts for one pick only, it is easy to realise the extent
of the patterns which may be made; a cloth, for example, requiring
200 picks to the round, all of which may be different in the order or
number of ends lifted, would require a set of 200 cards.
In what is called a 400 machine, 408 hooks are used, the needles being
arranged in 51 rows of 8 each; one row only is shown in Fig. 62, thus
the others are arranged at the back of the one shown and in line with
it.
Public-domain text, read in full here on John Shaqi.
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