Cams and followers

Cam and Followers:

A cam is a rotating mechanical device which transmits reciprocating or oscillating motion to another element known as follower by direct contact. The driver is called the cam and the driven member is called the follower. A very common example is the camshaft of an automobile engine, where the cams drive the push rods (the followers) to open and close the valves.

Types of cams:

On the basis of shapes:

a) Radial or Disk cam: The follower axis moves in a plane perpendicular to the axis of rotation of the camshaft.

radial-cam

 

b) Cylindrical cam: The follower reciprocates or oscillates in a direction parallel to the cam axis.

cylindrical-cam

 

c) Translating cam: These are the types of cams having specified motion of the follower. The contour or the shape of the groove is determined by the specified motion of the follower.

 

Types of followers:

(i) Based on surface in contact:

(a) Knife edge follower

(b) Roller follower

(c) Flat faced follower

(d) Spherical follower           

types-of-followers-according-to-shapes

 

(ii) Based on type of motion:

(a) Oscillating follower: When cam rotates, follower oscillates.

(b) Translating or reciprocating follower: When cam rotates, follower translates or reciprocates. 

oscillating-and-translating-follower

 

(iii) Based on line of motion:

(a) Radial follower: The line of motion of follower passes through the axis of rotation of the camshafts.

(b) Off-set follower: The line of motion of follower is offset from the center of the camshafts.