PART A

1.What are the conditions to be fulfilled obtain a four bar crank rocker mechanism?

2.Define inversion of kinematic chain

In a four bar kinematic chain all links are free, motion will be unconstrained. When one link of a kinematic chain is fixed, it works as a mechanism. From a four link kinematic chain, four different mechanisms can be obtained by fixing each of the four links turn by turn. All these mechanisms are called inversions of the parent kinematic chain.

3.What is the condition to be met for correct steering?

Automobiles are controlled by the steering system. Directional changes are provided by the steering system to the moving automobiles. Steering is done by moving the axes of rotation of the front wheels with respect to chase frame.

4.State the purpose of indexing mechanism.

It is mechanism which divides the circumference into equal number of parts. It causes the work piece to more in a desired amount on its axis. it is used in watches, tool changes for CNC machine, bank note counting etc.

5.List out the inversions of double slider crank mechanism.

6.Define the rubbing velocity.

7.What is the prime circle of cam?

The smallest circle drawn to the pitch curve from the centre of rotation of the cam is called as the prime circle. In knife-edge follower, the base circle and the prime circle are the same. In roller follower, the radius of the prime circle is the base circle radius plus the radius of the roller.

List the motions of the follower, during its travel.

(i) Uniform motion,

(ii) Simple harmonic motion,

(iii) Uniform acceleration and retardation, and

(iv) Cycloidal motion

Why are sometimes the axes of translating roller follower in cam follower mechanisms offset from the axis of cam rotating?

Define tangential cam.

When the flanks of the cam are straight and tangential to the base circle and nose circle, the cam is known as tangent cam.

State the law of gearing.

The law of gearing states that for obtaining a constant velocity ratio, at any instant of teeth the common normal at each point of contact should always pass through a pitch point, situated on the line joining the centre of rotation of the pair of mating gears.

What is the difference between a simple gear train and a compound gear train?

What is interference in involute gear and how is it prevented?

What is a differential gear of an automobile?

Write the equation of friction torque for uniform pressure and uniform wear theories for a flat collar.

What is the condition to be fulfilled for obtaining maximum efficiency of a screw jack?

State the functional difference between a clutch and a brake.

What are the advantages of wire ropes over fabric ropes?