Classification of Cams and Followers
There is not a general classification for cam mechanical systems. However, the 'functional embodiments' and 'functions' of each sub-system have relatively few possibilities, which we can classify.
There is often confusion with the term cam-follower, in English at least. The term Cam-follower is often used for both the element that is in direct contact with the cam and the element that has its motion defined by the cam.
Where possible, I will use the term Cam-Follower for the part that has its motion defined by the cam.
There are two common shapes of the element that are in direct contact with he Cam - circular and flat. I will use the term Cam-Roller Follower when it is rolling bearing, and Flat-Faced Follower when it is a Flat-Face. For other shapes, it should be clear. from the context.
A General Classification of Cam and Cam-Follower Types:
The general shape of the cam is generated by the interaction of the cam and follower motions.
•The cam is a disc, plate, track, groove, conjugate, ramp, slot
•Spatial: the cam is cylindrical, barrel, globoidal,
The modes of cam motion are:
•The cam swings back and forth: ; the cam 'oscillates'
•The cam rotates continuously
•The slide back and forth; the cam 'reciprocates'
•The cam is a plate that is nominally 'Circular', fixed to a frame (most common on rotating machinery - such as bottle labelling, capping and filling machines).
•The cam is a ramp that is nominally 'Linear', for example it is a 'slot' or 'ramp'.
The shape of the follower influences the shape of the cam.
•Cylindrical Roller Follower
•Taper Roller Follower - use with barrel, globoidal and other non-planar cams.
•Barrel (also called a Crowned) Roller Follower.
•Logarithmic Roller Follower - the actual function is the intellectual property of each manufacturer.
•Knife-edged Follower - not a practical cam-profile shape, but included here for completeness
•Other 'general' shapes.
See Typical Cam-Profile Shapes
The modes of cam-follower motion are:
Rotating Followers: a lever:
•Swing back and forth: an oscillating follower
•Progressive motion, they index, in one direction
Translating Followers: a slider:
•Sliding back and forth: a reciprocating follower
•The Stationary Cam-Follower moves the Cam, not as common, molding machines, wedge
•A stationary follower might be used to position a cam part, like a 'wedge' cam.
The constraint between the cam and the follower shape influences whether the cam is 'open' or 'closed'.
The constraint between cam-follower and the cam is with:
•Gravity, Spring, Air-Cylinder, ...
Form Closed (also called Body Closed):
The constraint between the cam-follower and the cam is with a:
•Groove (Track), Rib, Slot, within which the cam-follower is constrained.
•Conjugate Cams: these systems require manufacturing and production accuracy for a follower to be in contact with each cam.
The follower returns to the same position after each cycle by reversing its direction of motion at some point in the cycle.
Progressive: (also called 'indexing', see also Indexing Cams) )
The follower moves progressively to a new position at the end of each cycle.
In most cases the follower is replaced by another follower at the end of a motion cycle. Equally spaced followers return to their original positions after a number of motion-cycle. Most indexing systems use several roller followers equally spaced around a follower wheel or 'turret'.