1. MEEN 4110 – Mechanisms Design Fall - 2010 Lecture 09
CAM

2. Up on completion of this chapter, the student will be able to
Chapters Objectives
Up on completion of this chapter, the student will be able to
Understand how to design a CAM-FOLLOWER Systems.

3. Cam
Follower

4. Cam
A cam is a rotating or sliding piece in a mechanical linkage used especially in transforming rotary motion into linear motion or vice versa. It is often a part of a rotating wheel (eg. an eccentric wheel) or shaft (eg a cylinder with an irregular shape) that strikes a lever at one or more points on its circular path. The cam 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 reason the cam acts as a lever is because the hole is not directly in the centre, therefore moving the cam rather than just spinning. On the other hand, some cams are made with a hole exactly in the centre and their sides act as cams to move the levers touching them to move up and down or to go back and forth.

5. Design of Cam Systems
The first stage in designing a cam system is the creation of a displacement diagram. A typical plate cam with an in-line roller follower is shown below with a displacement diagram. This figure shows the following characteristic features.
The rise- This is when the follower is moving away from the cam centre. The slope reflects the follower velocity.
The dwell- the is the period when the follower is stationary
The return - This is when the follower moves back towards the cam centre
The base circle on the cam is the smallest full diameter of the cam
The prime circle is centered on the cam rotation centre with radius at the follower roller centre when the follower is on the base circle
The cam profile is the shaped surface of the cam defining the follower motion

7. Cam Design

8. Types of Cams

9. Types of Joint Closers (cam/follower joint)

10. Follower Motion

11. Types of Followers

12. Obtaining the S Diagram

13. Unwrapping/Linearizing a Cam

14. Unwrapping/Linearizing a Cam

15. The S Diagram

16. Why S Diagram Cannot Have Negative Values
New

17. SVAJ Diagram

18. SVAJ Diagram

19. SVAJ Diagram

20. Type of Motion Constraints

21. Type of Motion Program RF = rise-fall RFD = rise-fall-dwell
RDFD = rise-dwell-fall-dwell

22. Double-Dwell Cam Design- Choosing SVAJ Functions

23. How Not Meet Cam Design Specifications (Linear Function)

24. SVAJ Diagram

25. SVAJ Diagram

26. Cycloidal Motion

27. Cycloidal Motion – SVAJ Diagram

28. a Diagram

29. v Diagram

30. s Diagram

31. Cycloidal Displacement Function

32. Polynomial Function

33. Polynomial Function

34. Polynomial Function

35. SVAJ Diagram

36. Polynomial Function

37. Polynomial Function

38. Polynomial Function

39. Polynomial Function

40. Double Dwell Cam Design

41. Double Dwell Cam Design

42. Double Dwell Cam Design

43. Double Dwell Cam Design

44. Double Dwell Cam Design

45. Single Dwell Cam Design

46. Single Dwell Cam Design

47. Single Dwell Cam Design

48. Single Dwell Cam Design

49. Single Dwell Cam Design

50. Single Dwell Cam Design

51. Homework6  www.bc.inter.edu/facultad/omeza