Saturday, September 28, 2019
SECONDARY LOOM MOTIONS, TAKE-UP MOTION AND LET-OFF MOTION
SECONDARY LOOM MOTION:
The loom motions which help to weave a fabric continuously are called secondary loom motions. The fabric can be woven without these motions too, but you can't keep the weaving process continue without secondary motions. There are following two secondary motions required to make continuous weaving process.
Take - up motion:
"The main objectives of the take - up motion are to pull the fabric forward after beating of every inserted pick and to maintain the picks per inch required in the fabric".When the beating is completed, loom reed starts to change the position, it reaches to back dead center position and gets remained stationary during picking. The reed again performs beating motion. This cycle gets repeated periodically. The position of the fell of the cloth starts to shift it's position toward the reed in the absence of a suitable continuous fabric pulling mechanism. Thus a suitable and continuous fabric pulling mechanism keeps the fell of the cloth position unchanged during continuous weaving. In this way, we can say that " A continuous fabric pulling mechanism which helps to keep the fell of the cloth position unchanged during continuous weaving process is called take - up motion "
In this kind of mechanism, two objectives are achieved together. One is fabric pulling and second is cloth winding.
For fabric pulling, pin roll, Emery roll, sand roll and spike roll are used. One or two pressure rolls are also used to prevent the slippage between fabric and emery roll. These pressure rolls are coated with felt cloth or rubber emery. The emery roll rotates with the help of a train of wheels. In today's looms the looms are equipped with motorized take - up motion. There is not any necessity to change pick wheel. Weaver needs to feed required picks per inch in the loom control system only.
The cloth is wounded on the cloth roller finally.
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