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Sunday, April 26, 2020

CAM & FOLLOWERS (Part-1)

CAM & FOLLOWERS:-(Description, Overview, Types):-


Cam Follower Ends Design and Technology Diagram Secondary Bw RGB
Cam And Follower Setup (Neat Sketch)

CAM & FOLLOWER:-

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. The cams are usually rotated at uniform speed by a shaft, but the follower motion is predetermined and will be according to the shape of the cam. The cam and follower is one of the simplest as well as one of the most important mechanisms found in modern machinery today. The cams are widely used for operating the inlet and exhaust valves of internal combustion engines, automatic attachment of machinery, paper cutting machines, spinning and weaving textile machinery, feed mechanism of automatic lathes etc.

 Classification of Followers:- 


1. According to the surface in contact:-

(a) Knife edge follower:- When the contacting end of the follower has a sharp knife edge, it is                                                       called a knife edge follower.

(b) Roller follower:- When the contacting end of the follower is a roller, it is called a roller follower.

(c) Flat faced or mushroom follower:- When the contacting end of the follower is a perfectly flat                                                                       face, it is called a flat-faced follower.

(d) Spherical faced follower:- When the contacting end of the follower is of spherical shape, it is                                                          called a spherical faced follower.


2. According to the motion of the follower :- 

(a) Reciprocating or translating follower :-  When the follower reciprocates in guides as the cam                                                                               rotates uniformly, it is known as reciprocating or translating follower.

(b) Oscillating or rotating follower:- When the uniform rotary motion of the cam is converted into                                                                   predetermined oscillatory motion of the follower, it is called oscillating or rotating follower.


3. According to the path of motion of the follower :-

(a) Radial follower :- When the motion of the follower is along an axis passing through the centre                                           of the cam, it is known as radial follower.

(b) Off-set follower:- When the motion of the follower is along an axis away from the axis of the                                           cam center, it is called off-set follower.








Classification of CAMs :- 

1. Radial or disc cam :- In radial cams, the follower reciprocates or oscillates in a direction                                                         perpendicular to the cam axis. 

2. Cylindrical cam :- In cylindrical cams, the follower reciprocates or oscillates in a direction                                                parallel to the cam axis. The follower rides in a groove at its cylindrical 
surface.




Terms Used in Radial CAMs :-

1. Base circle:-  It is the smallest circle that can be drawn to the cam profile.

2. Trace point :-  It is a reference point on the follower and is used to generate the pitch curve. In                                     case of knife edge follower, the knife edge represents the trace point and the pitch curve corresponds to the cam profile. In a roller follower, the center of the roller represents the trace point. 

3. Pressure angle :- It is the angle between the direction of the follower motion and a normal to the                                      pitch curve. This angle is very important in designing a cam profile. If the pressure angle is too large, a reciprocating follower will jam in its bearings. 

4. Pitch point :-  It is a point on the pitch curve having the maximum pressure angle.
5. Pitch circle :- It is a circle drawn from the center of the cam through the pitch points. 

6. Pitch curve :- It is the curve generated by the trace point as the follower moves relative to the                                    cam. For a knife edge follower, the pitch curve and the cam profile are same whereas for a roller follower, they are separated by the radius of the roller. 

7. Prime circle :- It is the smallest circle that can be drawn from the center of the cam and tangent to                               the pitch curve. For a knife edge and a flat face follower, the prime circle and the base circle are identical. For a roller follower, the prime circle is larger than the base circle by the radius of the roller.
8. Lift or stroke :- It is the maximum travel of the follower from its lowest position to the topmost position.

Credit (Resources) :- Theory of Machine By Khurmi & Gupta.

To download the Book Click Here.

Click Here To see The CAM & FOLLOWER (Part-2)

Click Here To see The CAM & FOLLOWER (Part-3)

Click Here To see The CAM & FOLLOWER (Part-4)

Stay Tuned With Us.

©Mukesh Ch. Joshi
@ joshimukesh410820@gmail.com


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