CAM

The cam is a sliding or rotating piece in a mechanical linkage used especially in transforming rotary motion into linear motion or vice-versa.  This is a part of a shaft or a rotating wheel that strikes a lever at one or more points on its circular path. The cam mechanism can be a simple tooth, as is used to deliver pulses of power to a steam hammer, for example, or an eccentric disc or other shape that produces a smooth reciprocating (back and forth) motion in the follower, which is a lever making contact with the CAM.

The Use Of CAM:

The cam device is used to translate circular motion to reciprocating (or sometimes oscillating) motion. The camshaft of an automobile takes the rotary motion of the engine and translates it into the reciprocating motion necessary to operate the intake and exhaust valves of the cylinders. The opposite action, translation of reciprocating motion to circular motion, is done by a crank. Let us see an example, the crankshaft of a car, which takes the reciprocating motion of the pistons and translates it into the rotary motion necessary to operate the wheels. Cam devises are used for information-storing and -transmitting purpose. The best example is the cam-drums that direct the notes of a music box or the movements of a screw machine's various tools and chucks. The information that are stored and transmitted by the cam is the answer to the question, "What actions should happen, and when?" (Even an automotive camshaft essentially answers that question, although the music box cam is a still-better example in illustrating this concept.)

The cam plays a very important role in the operation of many classes of machines, especially those of the automatic type, such as printing presses, shoe machinery, textile machinery, gear-cutting machines, and screw machines. In different classes of machinery, automatic control and accurate timing are paramount; the cam is an indispensable part of mechanism. The use of cam is unlimited, and their shapes occur in great variety.