1. Shri S’ad Vidya Mandal Institute of Technology
CAMS
:MADE BY:
Alok Shah.
Divyajeetsinh Alonja.
Amit Modi.
Ankit Rana.

2. INTRODUCTION
A cam is a rotating or reciprocating mechanical element which transfers rotating, reciprocating or oscillating motion to follower by direct contact.
Generally the contact between cam & follower is a line contact, which generates higher pair.
The cam mechanism mainly divided in three parts.
A cam is known as driver member, which has a rotating or oscillating motion.
A follower is known as driven member, which has rotating, reciprocating or oscillating motion.
A frame is stationary part, which supports the cams and guides the follower.

3. CLASSIFICATION OF CAMS
According to the shape:
Wedge and flat cams:
In this cam, wedge has a reciprocating motion whereas followers has reciprocating or oscillating motion.

4. 2. Radial or disc cams:
In this cam, follower moves in a perpendicular plane to the cam shaft This type of cam is widely used due to its simplicity.

5. 3. Spiral cams: In this cam, a spiral groove is created in
disc. This slot consist
gear teeth.
The use of this type of cam is limited as the cam has to rotate in reverse direction for getting initial condition.

6. The cylindrical cam is devided in two types. The follower fixed at
4. Cylindrical cams:
This cam is also known as drum or barrel cam. In this type of cam, follower moves in a parallel plane to the axis.
The cylindrical cam is devided in two types.
The follower fixed at
one point and roller is at second end.Due to rotation of cylinder
the follower oscillates
about its fixed point.

7. 2) In second type, side of cam surface is in contact with roller follower.
The contact between cam surface and follower is maintained by using spring.

8. 5. Conjugate cams:
Two cylindrical disc are fixed with some eccentricity and two arm roller follower are in contact with two different disc periphery.
The benefit of this cam is better contact at high speed, low wear & noise.

9. 6. Global cams: This cam has two types.
Depend upon the cam surface it is known as “CONCAVE” & “CONVEX”.
This type of cam is used where large oscillation angle required.

10. 7. Spherical cams:
The cam has a spherical dome type shape and follower is fixed at one end.
Follower oscillates in axis perpendicular to the direction of cam axis.

11. b) According to the follower movement:
In cam mechanism as cam rotates, the follower moves up or down in his guide ways or oscillates in clockwise or anticlockwise direction about its fixed point.
Rise-Return(R-R-R):
In this type of cam mechanism, as cam start to rotate, the follower moves up and down during cam rotation.
There is no dwell period.
The follower moves up and down continuously without rest time.

12. 2. Dwell-Rise-return-Dwell(D-R-R-D):
In this type of cam mechanism, as cam start to rotate, initially for some time there is no follower movement after that follower moves up and come back to its initial position.

13. 3. Dwell-Rise-Dwell-Return-Dwell(D-R-D-R-D):
In this type of cam mechanism, as cam start to rotate, initially for some time there is no follower movement after that follower moves up.
Now once again there is no follower movement for some time and after that follower come back to its initial position.

14. c) According to the constrain of follower:
During cam rotation at one speed due to inertia of follower, the contact between cam surface and follower tips is lapse.
For good result and better control of movement it is necessary to maintain a constant contact between cam surface and follower tips. This is done by two ways.
Depend upon the ways, they are divided in three parts.

15. Preloaded spring cam:
A compression type of spring is used to maintain contact between cam surface and follower tips.

16. 2. Positive drive cam:
In this type of cam a special groove is generated in which a cam end oscillate or slide.
In this, the follower movement is limited and depends on the groove of cam.

17. 3. Gravity cam:
In this type of cam-follower mechanism, contact between cam and follower is maintained due to gravity force of follower.
The intensity of contact is depend upon the weight of follower.

18. CLASSIFICATION OF FOLLOWERS
The cam followers are divided into three types.
According to shape:
Knife-edge follower:
During working the rate of wear of contact point is high. Due to this, the use of this follower is very limited.
2. Roller follower:
During rolling action of roller the rate of wear is very small and working is smooth and silent. Due to this benefit, it is widely used.

19. 3. Mushroom follower:
There are two types of surface in mushroom follower
Flat faced
Spherical faced
Jamming problems of follower can be avoided by using mushroom follower.

20. b) According to movement:
Reciprocating follower:
In this type of follower during working of cam, the follower gets motion either reciprocating or translating.
2. Oscillating follower:
In this type of follower during working of cam, the follower oscillates with respect to a fixed pivot point.

21. c) According to location of line movement:
Radial follower:
In this type of follower, the line of movement of follower passes through cam centre.
2. Offset follower:
In this type of follower, the line of movement passes at some offset distance from the cam centre.

22. TERMS USED IN RADIAL CAM
Base cam: It is the smallest circle that can be drawn to the cam profile from the centre of rotation of cam.
Cam profile: It is the actual working contour of the cam with which the surface of the follower is always in contact and it transmits the required motion to the follower.
Trace point: It is the point on the follower which is used to generate the pitch curve.
Pitch Point:it is the point on the pitch curve of the cam having the maximum presure angle.

23. Pitch Circle: It is the circle drawn from the centre of the cam through the pitch point.
Prime Circle: It is the smallest circle drawn to the pitch curve from the centre of the rotation of cam.
Lift Of The Stroke: It represent the mximum travell of the follower from the base circle to its top most position.

24. Thank you