Tappet Shedding Mechanism

Experiment Name:-Study on tappet shedding mechanism.

Introduction:

Tappet is generally used for heald shedding. Tappet can be described as an irregular piece of mechanism to which a rotary motion is given for the purpose of producing by sliding contact, reciprocating motion in rods and levers. When the rod is to receive a series of lifts, with interval of rest, the piece is generally called a tappet.

 Objectives:

    To know about the different parts formed this shedding.

    To learn the mechanism of tappet shedding.

    To know the construction of tappet shedding.

Types of tappet:

Various kinds of shedding tappets are used in industries. 

They are of two main types:

1. Negative shedding tappet
2. Positive shedding tappet

Negative Tappet Shedding:

 In a tappet shedding mechanism, if the tappet controls only one movement, either an upward or downward movement of the heald shafts, then the shedding is known as “negative tappet shedding”. The heald shafts are returned by some external devices like springs, dead weights, rollers, etc.

Positive Tappet Shedding :

In a tappet shedding mechanism, if the tappet controls both upward and downward movements of the heald shafts, then the shedding is known as positive tappet shedding.

Main parts of Tappet Shedding Mechanism:

1. Motor.
2. Motor pulley.
3. M/C pulley.
4. Crank shaft.
5. Crank shaft gear.
6. Bottom shaft gear.
7. Bottom shaft.
8. Tappet.
9. Connecting rod.
10. Heald shaft.
11. Top arm.

Fig: Tappet shedding mechanism.

Position of fixation of shedding tappet:
The shedding tappets are may be fixed in different parts of a loom.

Namely-

1.     Under and over the centre of heald shaft.

2.     Under and over one end of heald shaft.

3.     Outside the loom framing.

Driving of shedding tappet:

In our loom tappet gets motion in the following way. At first machine pulley gets drive by belt from motor pulley. Then machine pulley, which is directly joined with the crank shaft, gives motion to bottom shaft. This crank shaft gives motion to bottom shaft via gearing. Two tappets are joined with the bottom shaft. So when bottom shaft moves then the tappets also rotate. When it gets contact with tradle bowl it lifts the tradle levers and the heald shafts are lifted by tradle levers via links. As this is a negative shedding tappet the heald shafts are lowered by their own weight.

Conclusion:

From this experiment we learn tappet shedding mechanism. Tappet shedding mechanism is important for driving loom. It is also important for fabric design. By this experiment we also learn the different parts of this mechanism. This would be very helpful in our future career.