There are three types of joints in a chain:
1. Binary Joint: When two links are joined at the same connection, the joint is known as binary joint.
2. Ternary Joint: When three links are joined at the same connection, the joint is known as as ternary joint. It is equivalent to two binary joints as one of the three links joined carry the pin for the other two links.
3. Quaternary Joint: When four links are joined at the same connections, the joint is called a Quaternary joint. It is equivalent to three binary joints.