1. CAMS WITH SPECIFIED CONTOURS
LUKHDHIRJI ENGINEERING COLLEGE MORBI
CAMS WITH SPECIFIED CONTOURS
BRANCH: MECHANICAL ENGINEERING SEMESTER: 3 YEAR:   GUIDED BY: Prof. I.B. SHAH
PREPARED BY:
Agarwal Prasoon S ( )
Albad Ravindra C ( )
Gosai Anandpari K ( )

2. Cam
Cam - A mechanical device used to transmit motion to a follower by direct contact.
Cam – driver; Follower - driven
In a cam - follower pair, the cam normally rotates while the follower may translate or oscillate.
Cams are used to convert rotary motion into reciprocating motion

3. Three elements of the cam

4. CLASSIFICATION OF CAMS
(i) Based on the physical shape (a) Disk or plate cams

5. (b) Cylindrical cam

6. Translation Cam (Wedge Cam)
Not very commonly used. The cam moves over and back, reciprocating motion, which drives the follower vertically.

7. CLASSIFICATION OF FOLLOWES
Based on surface in contact
(a) Knife edge follower
(b) Roller follower
(c) Flat faced follower
(d) Spherical follower

8. KNIFE OR POINT EDGE FOLLOWER
FLAT FACED FOLLOWER
ROLLER FOLLOWER

9. (ii) Based on type of motion
Oscillating follower
Translating follower

10. (iii) Based on line of action
Radial (in line) follower

11. (b) Off-set follower

12. (iv)According to the shape of follower
Knife edge follower
Roller follower
Flat faced follower
Spherical faced follower

13. Classification of CAM Mechanism
Based on modes of Input / Output motion
1 Rotating cam –Translating follower
2 Rotating cam – Oscillating follower
3 Translating cam – Translating follower

14. . CAM Nomenclature

16. Cam profile : The outer surface of the disc cam.
Base circle: The smallest circle drawn on the cam profile.
Trace point: The center line of the follower roller or its equivalent.

17. Pitch curve: The locus of successive positions of the trace point as cam displacement takes place.
Prime circle: The smallest circle drawn on the pitch curve from the cam center.
Pressure angle: the angle between the normal to the pitch curve and the instantaneous direction of motion of the follower.

18. Cam terms
Pitch point: The position of the pitch curve where the pressure angle is maximum.
Pitch circle: The circle which passes through the pitch point.

19. Example of cam action

20. Cam-Valve

21. CAMS WITH SPECIFIED CONTOURS
INTRODUCTION
Based on the flank, cams are classified into two groups,
Circular arc cam
Straight edged cam or Tangent cam
ANALYSIS OF CAMS

22. Circular arc Cam:
When the flanks of the cam connecting the nose and base circles are of convex circular arc, such cams are referred as circular arc cams.

23. Tangent cam:
When the flanks between the nose and base circles are of straight and tangential to both the circles, then, the cams are called tangent cams.

24. These are usually symmetric about the centre line of the cam
These are usually symmetric about the centre line of the cam. Generally, the following combinations of cam and follower are used.
Circular arc cam with flat faced follower:
(i) When the flat face of the follower has contact on the circular flank.
(ii) When the flat face of the follower has contact on the nose.
(b) Tangent cam with reciprocating roller follower:
(i) When the roller has contact with straight flanks.
(ii) When the roller has contact with the nose.

25. CIRCULAR ARC CAM WITH FLAT FACED FOLLOWER
The figure below represents various main dimensions of circular arc cam.

26. (a) Expression for determining the displacement, velocity and acceleration of the follower when flat face of the follower has contact on the circular flank

30. (b) Expression for determining the displacement, velocity and acceleration of the follower when flat face of the follower has contact on the nose

34. TANGENT CAM WITH ROLLER RECIPROCATING FOLLOWER
Tangent cams are made with straight flanks. A tangent cam is shown in figure below The flanks AB and IH are straight lines and tangent to the base circle at A and I and tangent to nose at B and I. The centre of the circular nose is P. The path of the centre of roller follower is shown by dotted line.

35. a. Expression for determination of displacement, velocity and acceleration of the roller follower when in contact on the straight flank

40. (b) Expression for determination of displacement, velocity and acceleration of the roller follower when in contact with nose

44. REFERECNCES: