MOTION IN WEAVING:-

(B) SECONDARY MOTION OF LOOM:-

Now I am going to give explanation about  the secondary motion which are used in weaving.

Types of secondary motion and it’s working principle:-

There are two types of secondary motions of loom,  they are;

A) Take-up motion, and

B) Let-off motion.

(A) TAKE-UP MOTION:-

The function of take-up motion is to draw fabric on to the cloth roller regularly and withdraw the cloth from the weaving area at regular and constant rate so as to give the required pick-spacing (in pick/cm or pick/inch ) and then wind it to cloth roller. Take-up motion determines the number of ends and picks per centimeter or inch. The main part of this motion (mechanism) is  that the take-up rollers, which draws at the regular rate, and the number of picks per inch decided in the fabric. The take-up roller covered with emery cloth or hard rubber, depends on the types of cloth woven. The drive to the take-up roller is by a train of gear wheels put into motion straightly from the main shaft.

Classification of take-up motion:-

Take-up motion are classified in many way, They are;

According to Drive,

(a) Negative Take-up.and

(b) Positive take-up.

According to motion of the cloth /rate of take-up..

(a) Continuous.

(b) Intermittent.

According to drive given to the cloth roller,

(a) Direct drive.

(b) Indirect drive.

According to number of gear train,

(a) Five (5) wheel.

(b) Six (6) wheel and,

(c) Seven wheel.

According to brand name,

(a) Sulzer.

(b) Picanol.

(c) Toyota.

According to drive,

A) NEGATIVE TAKE-UP MOTION:-

The word negative justify the take-up motion that no positive or direct motin is imparted to the take-up roller to wind the woven cloth. In this motion which the take-up roller is rotated by means of a weight or spring , the roller only rotates when the force is applied by the weight or spring, is greater than the warp lay tension in the fabric. In this way, the motion of the rocking shaft actuates a system of levers and ratchet pawl mechanism favoured by gravity aided movement of dead weight which in turns transmits the rotational motion to take-up roller through a worm and worm wheels.

Diagram of negative take-up motion.

Working principle:-

The backward motion of slay or back swing of the rocking shaft(R) keeps the weight raised by a lower (L), thus system stay inactive, while forward motion of it sets free the weight system yet motion of the wheel train remains balanced with warp tension till impulsive blow of it during beat up brings the tension if woven fabric cloth to zero. Weight going down with gravity make the pawl (P) to jump retaining pawl (P) comes into play to prevent the further rotation of gear trains . With the little control over uniform take-up or pick spacing system is only suitable for coarse count.

Ref:-https://textilelearner.com