Tappet

A type of cam to which a rotary motion is given for the purpose of producing reciprocating motion in rods & levers by sliding contact when the rod is received a series of lifts, when intervals of rest & thus form a shed is called tappet.

Scope of tappet shedding:

1. Maximum number of heald shaft capacity is 14 (practically 10 tappets are available).
2. Normally it produce square design (e.g. 4 × 4, 6 × 6 etc).
3. It produces only basic fabric structure.
4. Small design can be produced.

Types of tappet shedding:

Various kinds of shedding tappets are in use in the industry. They are constructed on two principles-

Positive shedding tappets: Two tappets for one heald shaft. Example:

1. Wood croft’s section tappet.
2. The oscillating tappet.
3. Nuttall’s chin tappet.
4. Scroll tappet.

Negative shedding tappet: One tappet for one heald shaft. Example:

1. Ordinary plain & twill weave shedding tappet.
2. Jamieson’s tappet.
3. Barrel tappet.

Difference between tappet & ordinary tappet:

Tappet	Ordinary tappet
1. It gives motion to a shaft to receive a series of lifts, with intervals of rest.	1. It gives a continuous reciprocating motion.
2. It is mainly used to produce a shed.	2. It may used for many purpose.
3. All tappets are cam.	3. All cams are not tappet.