Theory
Explain a scotch yoke mechanism with a neat sketch.
Compare multiplate clutch with cone clutch on the following basis.
Comparison of multiplate clutch and Cone clutch:
State any four inversions of single slider crane chain. Describe any one with neat sketch.
1.Reciprocating engine, Reciprocating compressor;
2. Whitworth quick return mechanism, Rotary engine,
3.Slotted crank mechanism, Oscillatory engine.
4.Hand pump, pendulum pump.
1.Reciprocating engine, Reciprocating compressor link 1 is fixed
2.Whitworth quick return mechanism, Rotary engine link 2 is fixed,
State the adverse effect of imbalance of rotating elements of machine.
Adverse effect of imbalance of rotating elements:
a) Vibration, noise and discomfort,
b) Machine accuracy get disturbed,
c) Power losses,
d) More maintenance
Define fluctuation of energy and coefficient of fluctuation of energy.
a) Fluctuation of energy -- The difference of maximum and minimum kinetic energy of flywheel is known as Fluctuation of energy
b) Coefficient of fluctuation of energy -- - It is defined as the ratio of the maximum fluctuation of energy to the work done per cycle. It is denoted by ke = (E1 - E2)/work done per cycle
State the effect of centrifugal tension on power transmission.
Effect of centrifugal tension on power transmission:
As the belt passes over the pulley with high velocity, centrifugal force is produced on the belt, which tends to act on the belt. This force tries to move the belt away from the pulley.
This force is given by,
TC = m x V2
There is no effect of centrifugal tension on power transmitted.
Give four advantages of chain drive over belt drive.
Advantages of chain drive over belt drive
a) No slip takes place in chain drive as in belt drive there is slip.
b) Occupy less space as compare to belt drive.
c) High transmission efficiency.
d) More power transmission than belts drive.
e) Operated at adverse temperature and atmospheric conditions.
f) Higher velocity ratio. g) Used for both long as well as short distances
Define slip and creep in case of belt drive.
Slip --- Slip is defined as insufficient frictional grip between pulley (driver/driven) and belt. Slip is the difference between the linear velocities of pulley (driver/driven) and belt.
Creep ----- Uneven extensions and contractions of the belt when it passes from tight side to slack side. There is relative motion between belt and pulley surface, this phenomenon is called creep of belt.
State the advantages of roller follower over knife edge follower.
Advantages of roller follower over knife edge follower a) Roller follower has less wear and tear than knife edge follower. b) Power required for driving the cam is less due to less frictional force between cam and follower.