TYPES OF JACQUARD SHEDDING ( CROSS BORDER JACQUARD):-

CROSS BORDER JACQUARD:-

CHARACTERISTICS:-

(1) In ordinary single lift and double lift Jacquards cross border and ground figures may be woven by using as many cards as there are picks in the whole piece. This often means using a few thousand cards for weaving a cloth.

(2) The number of cards, however, may be saved by lacing two sets separately, one set of cards for the cross border and another set for the border and body weave, and changing them when required.

(3) On the handloom mounted with a Jacquard, it is usual for the weaver to change the cards by hand, substituting cross border cards for the body or middle cards and vice versa, but on the powerloom the cards are changed either by hand or automatically.

(4) Sometimes on a double lift cylinder Jacquard, the cross border cards are passed round one cylinder and the body cards round the other. One cylinder and one griffe are worked at a time unil change is required. The above plans are quite unsuitable for high speed looms.

(5) The object of the cross border Jacquard is, therefore to save the expense of cards in sarees, handkerchiefs, table covers, bed sheets, towels, curtains and other bordered fabrics.

DETAILS OF CROSS BORDER JACQUARD:-

The cross border Jacquard, illustrated in fig.127, is the invention of Messrs Crossley and Davenport. The machine is double lift, as will be seen from the connection of the neck-cord. This Jacquard is constructed with double cylinders and a duplicate set of needles. Both sets of needles move the same hooks, but one cylinder is always stationary. This Jacquard is also suitable for high speed looms.

The cross border cards are put on one cylinder B , and the middle cards on the another cylinder A. When cylinder A presses back a needle, say, the top needle C, it will press back the pair of hooks EF, as in an ordinary double lift single cylinder Jacquard. And as long as this cylinder is worked every pick, the machine is as good as a double lift single cylinder Jacquard.

Fig.127 cross border jacquard.

 When this cylinder is stopped and the cylinder B is worked every pick, the cards on the cylinder B have exactly the same effect on the ends as those on the cylinder A. As, when the top needle in this set of needles is pressed back, it will force backward the pair of hooks EF, exactly as operating needle C by the other cylinder did. Only one spring-box S is used, as the upright wires MM pass through loops or bends P in the long needles C, and the small iron bars HH act as fulcrum for the wires MM. The tops of these wires are fastened to the short needles N, and thus when the needle N is pressed back, it moves the needle C in the opposite direction and operates the hooks EF. The needles C are about 48 cm. long with an extra bend each. The short needles N are 20.3 cm. long.

Mechanism of Change of Cylinder:-

In the cross border Jacquard it becomes necessary to change the cylinders substituting cross border weave for the body or middle weave. The mechanism for change of cylinders in the cross border Jacquard is illustrated in fig.128.

fig. 128 mechanism of cylinder chage.

When the parts are in the position shown in the diagram, the cylinder A will be pressed against the needles C every pick. (Fig.127). The cylinder A and B are driven from the crankshaft. The rod X goes to the crankshaft and a reciprocating motion is given to the L-lever CD, centred at E. The rocking lever FG is in a position to move about it’s centre K, without moving the cylinder B . Thus , ad the crankshaft of the loom revolves, it will give motion to the cylinder A, but not to B.

The cord or wire L is secured to lever SR, and also a quadrant handle Y. The handle Y is retained in a fixed position by one of two projections on the quadrant face. By moving Y to the next stop, the rocking lever FG change places, and the arm N begins to move the arm M becomes stationary. The cylinder A and B may be put in or out of action either manually or automatically. 

In the illustration the change of cylinder is to be made manually; additional piece of mechanism must , therefore , be added to change them automatically. There are other cross border motions, but this device is most commonly used in the industry.

Ref:-Weaving Mechanism Book Vol.1 by Prof. N. N.Banerjee.