Register Number
SATHYABAMA UNIVERSITY
(Established under section 3 of UGC Act,1956)
Course & Branch :B.E - MECH/AUTO
Title of the Paper :Kinematics of Machines
Sub. Code :515302-615301
Date :07/05/2011
Max. Marks :80
Time : 3 Hours
Session :AN
______________________________________________________________________________________________________________________
1.
PART - A
Answer ALL the Questions
Define mobility (degrees of freedom)
2.
State Grashof’s law.
3.
How many links and joints are in the four bar mechanism and
find the kutzbach criterion?
4.
Give the applications of crank and slotted link quick returns
mechanism.
5.
Write the types of followers.
6.
Define Reactive forces.
7.
State “law of gearing”.
8.
Define interference in gears.
9.
What is the height is watts governor (in Meter)?
10. What is the function of Governor?
(10 x 2 = 20)
PART – B
Answer All the Questions
(5 x 12 = 60)
11. (a) State and prove Kutzbach criterion for the following
kinematic chains
(i) Three Bar chain
(ii) Cam with knife edge follower
(b) Explain in detail the Watt’s indicator mechanism.
(or)
12. In a four link mechanism, the crank AB rotates at 36 rad/Sec. The
length of the links is AB=200 mm, BC = 400mm, CD = 450mm
and AD=600mm. AD is fixed link. At the instant when AB is at
right angle to AD, Determine the velocity and acceleration at
(a) Midpoint of the link BC.
13. Derive the Freudensteins equation for the four bar mechanism.
(or)
14. Define the following terms in synthesis and explain it.
(a) Types synthesis
(2)
(b) Number synthesis
(2)
(c) Dimensional synthesis
(4)
(d) Synthesis problem in function generation with example. (4)
15. Draw the profile of a cam operating a roller reciprocating
follower and with the following data. Minimum radius of cam =
25mm Lift = 30mm Roller diameter = 15mm. The cam lifts the
follower for 120 with SHM, followed by a dwell period of 30.
Then the follower lowers down during 150 of cam rotation with
uniform acceleration and retardation followed by a dwell period.
If the cam rotates at uniform speed of 150 rpm. Calculate the
maximum velocity and acceleration of the follower during the
descent period.
(or)
16. The turbine rotor of shop has a mass of 3500 Kg. It has a radius
of gyration of 0.45m and a speed of 4000 rpm. Clockwise when
looking from stern. The gyroscopic couple and its effect upon the
ship.
(a) When the ship is steering to the left on a curve of 100m radius
at a speed of 36 km/hr.
(b) When the ship is pitching in a simple harmonic motion, the
bow falling with its maximum velocity. The period of pitching is
40 seconds and the tool angular displacement between the two
extreme positions of pitching is 12 degrees.
17. (a) Parallel shafts are connected by a simple gear trains. The
speed of the driving gear and the driven gear is 360 rpm and 120
rpm respectively. The number of teeth on the driving gear is 30.
Determine (i) the speed ration (ii) The train value (iii) Number of
teeth on the driven or follower.
(b) A compound gear train consists of 6 gears. The number of
teeth on the gear is as follows.
Gear
A
No. of 60
Teeth
B
40
C
50
D
25
E
30
F
24
The gears B and C on one shaft while the gears D and F are on
another shaft. The gear A drives gear B, gear C drives gear D and
gear E drives gear F. If the speed of the gear A is 100 rpm, then
determine the speed of the gear F.
(or)
18. In an epicycle gear train an annular wheel A having 54 teeth
meshes with a planet wheel B which gears with a sun wheel C,
the wheels A and C being coaxial. The wheel B is carried on a
pin fixed on one wheels A and C. If the wheel A makes 20 rpm.
In the anticlockwise direction and the wheel C has 24 teeth,
Determine the speed and sense and sense of rotation of wheel C.
19. A porter governor has equal arms each 250mm long and pivoted
on the axis of rotation. Each ball has a mass of 5kg and the mass
of the central load on the sleeve is 15kg. The radius of rotation f
the ball is 150mm when the governor begins to lift and 200mm
when governor is at maximum speed. Find the minimum speeds
and range of speed of the governor.
(or)
20. In a spring loaded Hartnell type governor, the extreme radii of
rotation of the balls are 80mm and 120mm. the ball arm of the
bell crank level are equal in length. The mass of each ball is 2kg.
If the speeds at the two extreme positions are 400 and 420 rpm.
Find (a) Initial compression of the central spring and (b) The
spring constant.