Definition of Cam A cam is a rotating

Definition of Cam • A cam is a rotating machine element which gives reciprocating or oscillating motion to another element known as follower. • The cam and the follower have a line contact and constitute a higher pair. • Three elements : – Driver member – CAM – Driven member – Follower – Frame – to support the cam and guide the follower

• Application : – Internal combustion engine for operating valve – Shoe making machines – Sawing machine – Punch press – Paper cutting machine – Fuel pump diesel engine

Classification of Cams • • 1. 2. 3. Three types : According to Shape Follower movement Manner of constraint of follower

Wedge cam • Wedge has translation movement • Follower can translate or oscillate • Spring is used to maintain the contact between cam and follower

Radial or Disc cam Cam with knife edge follower Cam with spherical faced follower In radial cams, the follower reciprocates or oscillates in a direction perpendicular to the cam axis.

Cylindrical cam with reciprocating follower Cylindrical cam with oscillating follower In cylindrical cams, the follower reciprocates or oscillates in a direction parallel to the cams axis.

Globoidal cam

Spiral cam Groove is cut in the form of spiral which guides the follower

Spherical cam Follower oscillates about axis perpendicular to the axis of rotation of cam.

According to manner of constraint of follower 1. Pre-loaded spring cam Compression spring is used to maintain the contact between cam and follower.

According to manner of constraint of follower continue… 2. Positive drive cam Contact between cam and follower is maintained by roller follower which operates in groove of cam.

According to manner of constraint of follower continue… 3. Gravity cam Contact between the cam and follower is maintained due to the gravity or own weight of the follower.

Classification of Followers 1. According to Shape 2. According to the motion of the follower. 3. According to the path of motion of the follower

According to Shape

According to Shape Continue….

According To The Motion Of The Follower Oscillating Follower Reciprocating Follower

According To The Path Of Motion Of The Follower Radial Follower Offset Follower

Motion of the follower As the cam rotates the follower moves upward and downward. • The upward movement of follower is called rise (Outstroke) • The downward movement is called fall (Return stroke). • When the follower is not moving upward and downward even when the cam rotates, it is called dwell.

Wedge cam

Knife Edge Follower

Flat Faced Follower

Roller Follower

Cylindrical Cam

End Cam It is similar to cylindrical cam in which follower makes contact at periphery of cam.

Example

Example

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