Hall Ticket No:
Question Paper Code: A3317
VARDHAMAN COLLEGE OF ENGINEERING
(AUTONOMOUS) B. Tech IV Semester Regular/Supplementary Examinations, May 2018
(Regulations: VCE-R15) KINEMATICS OF MACHINERY
(Mechanical Engineering) Date: 22 May, 2018 FN
Time: 3 hours
Max Marks: 75
Answer ONE question from each Unit
All Questions Carry Equal Marks
Unit I
1.
Differentiate the following:
i. Structure and machine
ii. Mechanism and machine
iii. Completely constrained and successfully constrained kinematic chain
9M
Schematically explain the classification of kinematic pairs based on the relative motion between the elements.
6M
2.
Schematically explain the inversions of four bar mechanism.
9M
Illustrate with a neat sketch whitworth quick return motion mechanism.
6M
Unit II
3.
Explain the mechanism which is used to enlarge a given figure with proof.
6M
Obtain condition for correct steering for four wheeler. Sketch and explain the working of Ackermann steering gear. State its merits and demerits.
9M
4.
The Fig.1 shows quick return mechanism. Link 2 rotates uniformly at 20rad/s in clockwise direction. Determine angular acceleration of link
Fig.1
15M
Unit III
5.
Derive an expression for ratio of shaft velocities for universal joints.
8M
Explain with a neat sketch, the Davis steering gear mechanism.
7M
6.
Derive the condition for equal speed of driving and driven shaft in hook's joint.
10M
Two shafts with an included angle of 1600 are connected by a Hooke's joint. The driving shaft runs at a uniform speed of 1500r.p.m. The driven shaft carries a flywheel of mass 12Kg and 100mm radius of gyration. Find the maximum angular acceleration of the driven shaft and the maximum torque required.
5M
Cont…2

Unit IV
7.
Mention the factors to be considered for selection of belt.
5M
A cam is to give the following motion to a knife-edged follower:
i. Outstroke during 600 of cam rotation
ii. Dwell for the next 300 of cam rotation
iii. Return stroke during next 600 of cam rotation
iv. Dwell for the remaining 2100 of cam rotation
The stroke of the follower is 40mm and minimum radius of the cam is 50mm. The follower moves with uniform velocity during both the outstroke and return strokes. Draw the profile of the cam when the axis of the follower passes through the axis of the cam shafts.
10M
8.
Derive an expression for centrifugal tension of belt.
6M
A pulley is driven by a flat belt. The angle of lap being 120o. The belt is 100mm wide by 6mm thick and density 1000kg/m3. If the coefficient of friction is 0.3 and the maximum stress in the belt is not to exceed 2MPa, find the greatest power which the belt can transmit and the corresponding speed of the belt.
9M
Unit V
9.
Derive an expression for the minimum number of teeth required on the gear in order to avoid the interference in involute gear teeth.
8M
Two mating gears have 20 and 40 involute teeth of module 10mm and 20o pressure angle. The addendum on each wheel is to be made of such a length that the line of contact of each side of the pitch point has half the maximum possible length. Determine the addendum height for each gear wheel, length of the path of contact, arc of contact and contact ratio.
7M
10.
Explain briefly algebraic method of finding the velocity ratio of epicyclic gear train.
6M
In an epicyclic gear of sun and planet type shown in Fig.2, the pitch circle diameter of the internally toothed ring is to be 224mm and the module 4mm. When the ring D is stationary, the spider which carries three planet wheels C of equal size, is to make one revolution in the same sense as the sun wheel B for every five revolutions of the driving spindle carrying sun wheel B. Determine suitable numbers of teeth for all the wheels.
Fig.2
9M