Module 1   :   Dynamics of Rigid Bodies in Plane Motion; Dynamic Force Analysis of Machines
Lecture 1 :   Dynamics of Rigid Bodies in Plane Motion; Dynamic Force Analysis of  Machines.

Cam-Follower Joint with Sliding:

 

Two bodies with a cam follower joint which allows sliding are shown in Fig. 1.4(a) and the free body diagrams of the two bodies are shown in Fig. 1.4(b). There is only one reaction force which acts at the point of contact, and is normal to the surfaces at that point. The reaction force is a pushing force as shown and it cannot be negative. Negative value indicates separation of the two bodies. The reaction forces on the two bodies are equal and opposite, as required by Newton 's third law.

 

Fig. 1.1.4 Cam-follower-with-sliding
  Cam-Follower Joint with Pure Rolling:
  Two bodies with a cam follower joint which allows only pure rolling are shown in Fig. 1.5(a) and the free body diagrams of the two bodies are shown in Fig. 1.5(b). There are two reaction forces, both acting at the point of contact. is normal to the surfaces, while is tangential. has the same characteristics (only pushing) as the corresponding force in the case of cam follower joints with sliding. can be in any one of the two tangential directions. The reaction forces on the two bodies are equal and opposite, as required by Newton 's third law.

The joints considered above are those which commonly occur in planar mechanisms. We now show how the equations of motion of the mechanism can be derived using the free body (Newton-Euler) approach.

 

Fig. 1.1.5 Cam-follower-pure-rolling
   
1