Lesson 1 CAMS

Question 1

Cam is _______ machine element.

Answer 1

Rotating

Question 2

Follower is _______ element.

Answer 2

Driven

Question 3

Cam is ______ element

Answer 3

Driving

Question 4

Cam and follower constitute _______ pair. Why?

Answer 4

Higher pair. Because of line contact.

Question 5

Follower motion is _______ and will be according to _______ of cam.

Answer 5

Predetermined, shape

Question 6

Frame ______ the cam and _______ the follower.

Answer 6

Supports, guides

Question 7

In wedge cams, cam has _____ motion.

Answer 7

Translational

Question 8

In wedge cams, follower can ______ or ______.

Answer 8

Translate or oscillate

Question 9

In wedge cams, _______ is used to maintain contact between the follower and cam.

Answer 9

Spring

Question 10

In radial or disc cams, what is motion of follower?

Answer 10

Radially from centre of rotation of cam.

Question 11

How does follower move in radial or disc cams ( wrt cam axis)?

Answer 11

Reciprocates/ oscillates in direction perpendicular to cam axis

Question 12

What determines position of follower in radial or disc cams?

Answer 12

The radial distance from cam axis determines position of follower.

Question 13

Radial or disc cam assembly Held in position by _________ or _________.

Answer 13

Spring or gravity

Question 14

Describe spiral cams.

Answer 14

Face cam having Spiral groove consisting of teeth that mesh with pin gear follower.

Question 15

What is the velocity of follower proportional to in spiral cams?

Answer 15

Proportional to the radial distance of groove from axis of cam.

Question 16

Why are spiral cams used limitedly?

Answer 16

Because cam has to reverse direction to reset position of follower

Question 17

What is follower motion of types in cylindrical or drum cams?

Answer 17

1.) constrained/ positive oscillating motion in direction parallel to the cam axis
2.) End cam- end of cylinder is working surface and follower translates parallel to rotating cylinder

Question 18

Describe structure of conjugate cams

Answer 18

Two discs keyed together and in constant touch with two rollers of follower. One roller preloaded against other and in positive constraint.

Question 19

Characteristics of conjugate cams are:

Answer 19

1.) Precise
2.) Low wear
3.) Low noise
4.) Better control of the follower
5.) High speed
6.) High dynamic loads

Question 20

Globoidal cams are similar to cylindrical cams except that

Answer 20

Cylinder replaced with convex or concave globoids

Question 21

In globoidal cams, follower has ______ motion

Answer 21

Oscillatory motion

Question 22

Applications of globoidal cams

Answer 22

1.) Moderate speed
2.) Angle of oscillation of follower is large
For indexing purposes and specialized application.

Question 23

What is the form of cam surface in spherical cam?

Answer 23

In Form of spherical surface

Question 24

Describe movement of follower in spherical cam

Answer 24

Oscillates about an axis perpendicular to cam axis

Question 25

Describe movement of follower in disc or radial cams

Answer 25

Oscillates about an axis parallel to cam axis

Question 26

Follower motions distinguished from each other by _________

Answer 26

Dwells

Question 27

Define dwells

Answer 27

Zero displacement or absence of motion of follower during motion of cam

Question 28

Elucidate of R-R-R cam

Answer 28

1.) Alternate rise and return without dwell 2.) Linear or angular displacement 3.) Eccentric mechanism considered 4.) Limited use

Question 29

Elucidate on D-R-R-D cam

Answer 29

1.) Dwell rise return dwell cam 2.) Rise and return after dwell 3.) More frequent usage than R-R-R cam