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Seat No.: Enrolment
GUJARAT TECHNOLOGICAL UNIVERSITY
DIPLOMA ENGINEERING SEMESTER IV • EXAMINATION SUMMER- 2017
Subject Code: 341904 Date: 05 05 -2017
Subject Name: Theory of Machine
Time: 10:30 AM TO 01:00 PM Total Marks: 70
Instructions:
1. Attempt all questions.
2. Make suitable assumptions wherever necessary.
3. Figures to the right indicate full marks.
4. Each question carry equal marks (14 marks)
Q.1

Define kinematic pair and classify.
07



07

List the inversion of single slider crank mechanism. Explain any one of them with a neat figure.




Q.2

The crank of a reciprocating engine is 225mm long, and the connecting rod is 900 mm long. The crank is at 40° from inner dead centre position and engine speed is 150 rpm. Find velocity and acceleration of piston angular velocity of connecting rod.
07


225 mm 900 mm 150 rpm

07

State the principle of Kleins construction.Solve above problem by using Kleins construction method.




OR

In a four bar mechanism ABCD, AB cm, BC 12 cm ,CD =10 cm and AD =18 cm. BAD 60°. Link AD is fixed and point B and C lies on same side of AD. Link AB rotates at 60 rpm clock wise. Find velocity of link CD Angular velocity of link BC Velocity of midpoint E of link BC.
07

ABCD AB=7 cm, BC=12 cm, CD=10 cm AD=18 cm AD B C AD AB 60 . . . CD BC BC E
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Q.3

Draw cam profile for a cam, operating a pivoted follower from the following data. The follower moves outward with S.H.M during 120° rotation of cam. The follower remains lifted during 90° rotation of cam. The follower moves inward with uniform velocity during 120° rotation of cam. The follower remains at the bottom for the rest of rotation . stroke of follower 42 mm.least radius of cam 35 mm.The follower is radial and the cam shaft rotates in anticlockwise direction.
07


S.H.M. 120° 90° 120° 42 mm 35 mm

07

Explain with neat sketches different types of cams and followers.




OR
Q.3

A vertical shaft of a machine rotating at 75 rpm rests on a flatend in foot step bearing.The axial load on the shaft is 25 KN and shaft diameter is 400 mm .If co-efficient of friction is . 05, find the power lost in friction assume uniform wear.
07


400 mm 75 rpm 0.05 25 KN
07

Explain the working of multiple clutch with the help of a neat sketch.




Q.4

Explain the function of flywheel. Give difference between flywheel and governor.
07


.
07

Explain the working principle of Proell governor.


(Proell)

OR
Q.4

Derive the expression for centrifugal tension in power transmission.
07



07

Explain the working of epicyclic gear train with a neat sketch.

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Q.5

Prove that for maximum power transmission the centrifugal tension is 1/3 rd of total tension in the belt.
07


1/3 .
07

Define Critical speed, degree of freedom and amplitude




OR
Q.5

List the causes of vibrations. State the remedies for it.
07



07

Define slip. State its effects. State the methods of reducing slip.