Fig. VI. illustrates a needle, as used in connection with the hook.
Distance from head to loop, 9-1/8 inches, = _a_ to _c_. Length of loop,
1-5/8 inches, = _c_ to _d_. 10-3/4 inches entire length.
[Illustration: Fig. VI.]
The distance from head to eye (for passing through the hook) is
regulated according to the row in which the needle belongs. In the
present illustration this is, Head to eye, = 7 inches, = _a_ to _b_.
The eye, = 3/8 inch, = _b_.
Eight different positions of the distance of the eye from head will be
required by an 8-row machine. The needles are made of No. 15-1/2 bright
spring wire. The loop on the end, _c_ to _d_, permits a pin to be
inserted, [see Fig. VII., _o_], and also holds the needle in position.
[Illustration: Fig. VII.]
Fig. VII. gives a clear understanding of the arrangement of hooks,
needles, griffe-bars, springs, frame for holding the latter, and the
needle-board. This drawing is in accordance with the preceding ones,
executed one-fourth of the actual size, and represents the sectional
cut of one cross-row in the Jacquard machine containing 8 hooks, (as it
is an 8-row deep machine which we explain): _e_ to _e´_, 1st hook; _f_
to _f´_, 2d hook; _g_ to _g´_, 3d hook; _h_ to _h´_, 4th hook; _i_ to
_i´_, 5th hook; _k_ to _k´_, 6th hook; _l_ to _l´_, 7th hook; _m_ to
_m´_, 8th hook. These hooks are held in their required places by the
eyes of the needles [see place _v_ at hook 1], through which the former
are passed.
The needles rest with their heads in the needle-board, _a_ to _b_,
extending outside, towards the cylinder, for about 1/2 inch. The rear
part of the needle--the loop--is passed between two bars of the spring
frame, _n_, _p_, and held by the latter firmly, but with sufficient
play for a longitudinal motion for pressing towards their springs. The
pin, _o_, is inserted for holding the springs in their places. One pin
is required for each vertical row of needles. The part of the spring
frame, _r_, _n_, _p_, _s_, unshaded, is made of cast iron; the shaded
part (extension) is constructed of wood. Below the upper crook of the
hooks, the black sections represent a sectional cut of the griffe-bars;
_v_ to _w_ indicates the rester for the lower hooks, which keeps the
latter in their required position.
A study of this illustration will show that when the heads of the
needles, _a-b_, are pushed backwards, in the direction of arrows,
the hooks are also moved. If the needles are not pushed, the upper
crooks of the hooks will remain in position, as in drawing, over the
griffe-bar; and raising the latter will consequently raise every one
of these hooks. Therefore, if a blank card is pressed against the 208
needles of the machine, all the needles and hooks will be pushed back,
out of the way of contact with the griffe-bars, thus causing an empty
lift when they are raised; whereas, by pressing with an empty cylinder,
or with a card, containing as many holes as the machine has needles,
and so placed that the holes are exactly opposite the needles, none
of them would be moved, and each hook would remain vertical over its
griffe-bar; and raising the griffe will lift every hook.
As mentioned before, the springs, _u_, are attached to the needles
between the needle-frame, _n-p_, and the pin, _o_. Fig. VI., the
distance _e_ to _f_ indicates the part of the loop around which the
spring is adjusted, and where it rests against the expansion of the
loop. _f_, in Fig. VI., represents the place where pin, _o_, (as
shown in Fig. VII.) passes through the loop and is fastened to the
needle-frame on top and bottom. Pressing the needle at the head
compresses the spring, as the latter is securely fastened on one end by
the wider part of the loop, and on the other end by a pin inserted in
the loop and fastened to the frame. Remove the pressure at the head of
the needle, and the spring will return to its natural position, pushing
the needle into its old place. These springs are made of thin brass
wire.
It is necessary to keep the needle-eyes in the proper place, otherwise
it would result in bending the hook out of its perpendicular position,
and by lowering the griffe its bars would possibly come in contact with
the head of the hook, crushing the latter, or doing more damage if not
detected at once. Each needle or hook, if worn out, can be replaced by
pulling out the pin, _o_, thus loosening the needle and giving a chance
to work the required hook out of the needle-eye.