A cam mechanism converts rotary or linear motion from a cam into reciprocating swing or linear motion of a follower. It is a typical intermittent motion mechanism.
Core motion logic
A cam is a part with a curved profile or groove. It usually rotates continuously or moves in a straight line. The follower stays in contact with the cam profile. The cam drives the follower through a set motion curve, such as up-down movement or side-to-side swing. Contact types include knife-edge, roller, and flat face. Each type fits different applications.
Common types and principles
By cam shape:
Disk cam: the basic type, disk-shaped. The profile curve sets follower stroke. It is used for simple reciprocating linear motion, such as the thread take-up mechanism in small sewing machines.
Translating cam: the cam itself moves in a straight line and drives the follower. Example: early prototype of an internal combustion engine valve train.
Cylindrical cam: the disk cam profile is wrapped on a cylinder. When the cam rotates, the follower can produce more complex spatial motion. Common in automatic machine tool feed mechanisms.
By follower motion:
Translating follower: the follower moves in straight reciprocating motion. Example: common valve open-close mechanisms.
Oscillating follower: the follower swings around a fixed pivot. Often used in packaging machinery feed mechanisms.
Key parameters and design points
The cam profile must be designed to the follower motion requirements, such as lift, return, dwell time, and speed. A common design method is the reversal method. It treats the cam as stationary, which makes it easier to draw the profile. The cam and follower must stay in contact. This is usually done with spring force, gravity, or a locking structure.
Typical applications
Cam mechanisms are used in internal combustion engine valve trains, automated packaging machinery, machine tool feed mechanisms, printing machinery, sewing machines, and other equipment that needs accurate intermittent motion.
If custom cam plates, camshafts, followers, or roller components are needed, Hansheng Automation can machine them from customer drawings in single pieces or small batches.
