Motions of Loom

 The loom is distinguished from other machines by the specific motion or movements of the different machine parts. The loom basically performs three important motions. They are

1. Primary Motion 
2. Secondary Motion
3. Tertiary Motion

Primary Motions

 To interlace warp and weft yarn to make the fabric, the primary motions are necessary. There are three primary motions.

Shedding: shedding is the process of separating the warp thread into two layers so that the weft thread can pass through it. According to the design and form of fabric some of the warp yarn is raised up and the others are pushed down to create the shed or tunnel through which the weft thread can pass. The shed is produced by means of heald and harness.

Picking: the method of passing the weft thread which traverse across the fabric through the shed is called picking. The weft thread is passed from one selvedge to another by means of shuttle, rapier, water jet, air jet etc. This depends on the type of the loom being used.

Beating up: beating up is the process of pushing the pick into the already woven fabric at a point known as fell of cloth. This is done with the help of reed.

Secondary Motions

 The secondary motions of the loom mainly are concerned with moving the fabric through the different parts of the loom machine. It is also concerned with the feed and delivery of the yarn and fabric respectively. There are two secondary motions.

Take up motion: this motion consist of taking the woven fabric and winding it onto the cloth roller. This motion occurs in the delivery section of the loom. If the cloth is taken up onto to the cloth roller automatically then it is called positive take up motion. If the cloth is taken up on to the cloth roller manually then it is negative take up motion.

Let of motion: this motion is concerned with the delivery of warp to the weaving by unwinding the thread from the weaver’s beam at a constant rate. If the warn is let off from the weaver’s beam automatically then it is called positive let off motion. If the warn is let off from the weaver’s beam manually then it is called negative let off motion.

Tertiary Motions

 The tertiary motion is not a must for weaving, but it aids to increase production and reduce faults. The tertiary motions includes

1. Warp stop motion
2. Side weft stop motion
3. Centre weft stop motion
4. Weft patterning motion
5. Fast reed motion
6. Loose reed motion
7. Weft replenishment motion