Negative shedding Mechanisim (Negative tappet shedding)

Shedding: A shedding Mechanism separate the warp thread into two layer or division to form a tunnel that known as “Shed”. The shed provide passage for the shuttle. A shed may be formed by tappet, cams etc...

Types of Shedding

Negative shedding (Negative tappet shedding): In a tappet Shedding Mechanism, it tappet control only movement either upward or downward movement of heald shaft then shedding is known as “Negative Tappet Shedding”. The heald shaft are returned by some external device like springs, dead weight, roller Etc.   

Positive Tappet Shedding: In a tappet Shedding Mechanism, if the tappet controls both upward and downward movement of the heald shaft then the shedding is known as positive tappet shedding.

Working of Negative Tappet Shedding:

When the Bottom Shaft is rotated in clockwise direction then tappet are also rotated. The tappet will depress the anti-frictional bowl and the treadle fixed at back portion fulcrum and the front portion of the treadle move down. This action transferred to the lamb rod, the heald shaft and the leather strap so one heald shft is move downward. And this heald shaft form bottom layer.

 

The Leather Straps Attached to the Reversing Roller are connected in opposite directly. The heald shaft is raised and therefore the lamb rod and the treadle lever are also raised, and heald shaft are also raised and form the top layer of the shed.

For the next shed , the other tappet work with the other set of bowl , treadle, lamb rod, heald shaft, strap & roller and the other heald shaft is move downward add the first heald shaft is raised by the top reversing roller and the heald shaft movement interchange