Which of the following is NOT a cam follower type?

• A. Flat
• B. Roller
• C. Pivoted
• D. Ball

Answer: (D)

Cam followers are defined by how they interface with the cam and how they translate the cam’s motion. A flat follower has a flat face that slides directly on the cam surface, transferring motion with simple contact. A roller follower uses a rolling element between the follower and the cam to reduce sliding friction and wear, allowing smoother, longer life. A pivoted follower is mounted on a pivot or hinge, so its movement is constrained and follows the cam profile through a rotating or swinging link.

A ball as a follower isn’t a standard category in cam design because spherical contact would complicate the contact geometry and wear behavior, and it isn’t how cam followers are typically specified. Therefore, ball is not considered a cam follower type.