Thursday, November 13, 2014

Jacquard Weaving (Soji Muramatsu)

JAQUARD MACHINE

Sumber      : Muramatsu, Soji.1958.Jacquard Weaving.Murata Textile machine Co., Ltd:                        Kyoto,Jepang.

A.    Single lift Jaquard Machine
This is a quite ordinary type of jaquard and the mechanism is simple. In most cases, one warp end and in a figure repeat is controlled by one hook and the sheed formed is either the over-shed or the center shed
a.       Single lift cylinder over shed Jaquard Machine
In this type of jaquard, the hook-board is fixed and the hooks are moved only by the knives.
The warp ends, when the knives rise, are raised from the warp line and form the over shed according to the weaves. After the picks pass through, they must return to the warp line
Advantages
1.)    The shedding motion is simple
2.)    Warp ends are loaded with large tension during the shedding motion and thus woven fabrics with tight yarns are possible to produce.
Disadvantage
1.)    Half turning of crank shaft is not smooth on account of the closing of the shed, and the loom is loaded unevenly during the driving.
2.)    As it takes much time for  the shedding motion, high speed driving can not be employed.
3.)    During one revolution of crank shaft, the ratio of time for shedding much larger than that for the passage of shuttle, therefore this type of machine is not fit for looms of large width
4.)    Warp ends being strained in shedding, are easily torn.


b.      Single lift single silinder center shed Jaquard Machine
The knife box and the hook board move up and downward oppositely at the same time and thus two reverse directions of motion work on the hooks. Therefore some warp and the center shed is formed. The moving distance of warp ends for center shedding is about half in comparison with the over shed, and there are , besides, following advantages and disadvantages with this type of machine. However, this is a far more improved type than the over shed type of  jacquard machine.
Advantages
1.)    In shedding, the strain on the warp ends is small and very few are broken
2.)    Warp ends ascend and descend at the same time and according to the compensating principle motive power can be saved and still more, the uneven load on the loom is small
Disadvantage
1.)    The lingoes sway increasingly
2.)    Reed marks are often seen on the fabric
B.     Double lift jaquard machine
This type of machine, which control one warp end by two hooks, is equpped with two groups of knive which ascend and descend alternately. This works the above mentioned hooks, and the knives are so designed that one is at the top while the other is at the bottom. When the shedding motion commences, the lower knifes move upward and the upper ones move downward and meet in the middle of their course and they are replaced completely. Therefore these warp ends placed at the top or the bottom of the shed are moved respectively at the same time as the shedding motion begins.
In other words those warp ends which rest at the top of the shed, according to the descent of the upper knife, descent around the middle of the shed, and
1.)    The warp ends which need not to be raised in the following pick, as the lower hooks are not hung on the knife by pushing of the card paper, therefore the warp ends decent to the bottom rest line
2.)    The warp ends which need be raised in the following pick,as the lower hooks, are also hung on the knife till they reach the top of the shed, where the so-called semi-opened shed is formed
On the other hand, those warp ends rested at the bottom of the shed are raised around the center of the shed as the lower hooks ascend, but in case the hooks not being raised, they remain at the bottom,
They are two kinds of this types of machine, double lift single silinder and double lift double silinder jaquard machine. Both of which are good and weak in the followings:
Advantage:
1.)    The revolutions per minute of loom can be increased
2.)    As the time for the biggest shed is long, so the adjusment of picking is easy
3.)    The uneven load on the loom is small and the loom running is smooth
Disadvantage
As the warp ends are separated into two sheets, the warp tension is not even in shedding
a.       Double lift single silinder jacquard machine
There are two kinds of these machine, one has double the number of hooks with needles compared with the single lift jacquard machine and the other with the double number of hooks only.
Fig 16 is one of the latter type and the combination of hooks, needle and warp yarns are as follows:
Needle number
Hook number
Warp number
1
1 – 2
1
2
3 – 4
2
3
5 – 6
3
4
7 – 8
4
5
9 – 10
5
6
11 – 12
6
7
13 – 14
7
8
15 – 16
8

There are two kinds of knives, X and Y the former controls the odd numbered hooks and the latter, the even numbered ones. They move up and downwards alternately at every picking. Cylinder M as shown in the figure, approaches closely when the two kinds of knife situated at the top and bottom of the shed, and the cards contact with the needles thus one piece of card is used for every one pick
b.      Double lift double cylinder Jacquard machine
This machine seems to be like jaquard machine that is contructed with 2 sets of single acting jacquard which were fitted on a single jacquard framing. So they have 2 sets of cylinder, needles and hook and 2 sets of card are passed around the 2 cylinder respectively, the odd number cards are passed around the 2 cylinders respectively, the odd number cards hung around one cylinder, and the even numbered on the other , at every pick the cylinder move alternately.
Advantages
1.)    The hook recive less strain than in the case of the single cylinder machine
2.)    On high speed running, the cylinder beat againts the needles smoothly, smoother than the single cylinder machine
Disadvantages
The double cylinder machine has some unfortunate chances of defects on the cloth when both cyilinder would miss their regular acting order.
c.       Springless double lift double cylinder Jacquard machine
The ordinary ajcquard machine has a spring box, but the springless double lift double cylinder has none. Accordingly the hooks return motion will be done by itself by their own elasticity
In the figure 19 A, iron rods P are arranged side by side among the rows of pairs of hooks and they act as folcrum of the hook when they are pushed by needles.
When the needle manipulates a pair of hook, 2 knives X and Y are raised and lowered alternately, so that the knives move the warp the same as in the case of double cylinder machine and makes semi open shed.
  
C.     Cross Border Jacquard machine
It is used in manufacturing fabrics with figuresd border as handkechief or table cloth of fabric with skipped figures, being aimed at saving cards and high productivity. This machine equipped with two cylinders, one cylinder is used to figures on the ground part and the other for the border of fabrics. In other case the same (2 cylinder) are used for figures and the ground weaves.
Fig 20 shows one of this type machine based upon the double lift single cylinder Jacquard machine, where M and N stand for two cylinders, A for ordinary kind of needle s, E is auxilliary needles. Those two kind of needles are connected with vertical pins F. Needle E are not equipped for springs at their ends, but are pushed successively towards cylinder N by the spring of A by way of F.

D.    Veldol Jacquard machine
This new type jacquard machine and has finest needle pitch, in which the needle are arranged in zig zag line, moreover cotinous roll of paper are used for the card, therefore this small type machine can weave large figured cloth.
As shown in fig. 23 there are provided two kinds of hooks and needles H, h and N,n. And a endless cards paper is hung on the circular cylinder C, and that the perforated paper passed through between the cylinder and guide bar and the paper is moved forward by the action of cylinder rotation . auxiliary needles terminate at right end with a small head.
There are angle pieces “a”, which are oscillated laterally, when angled pieces are moved to the right , they push the corresponding needle N to the right, then the hooks  H are departed from knife edge.

The veldol Jacquard machine has many advantages, that making saving the cards and the lacing time mostly, the smooth running card can be get. However they have some disadvantags, the card  can not be mended when the card is miss cut, and the machine controlling is difficult and skillness is required for mastering the Jacquard machine, so that they are not worling at japan, generraly.