## Give detailed classification of followers.

## Procedure for balancing single rotating mass when its balancing mass is rotating in same plane:

## Formulae to calculate the length of open belt drive and length of Cross belt drive

**Formulae to calculate the length of open belt drive :**

## A Single slider crank mechanism:

Given: Crank AB = 20 mm = 0.02 m, C. R. BC = 80 mm = 0.08 m

N = 1000 rpm, ωBA= 2πN/60 = 2π x 1000/60 = 104.7 rad/sec

VBA = ωBA x AB = 104.7 x 0.02 = 2.09 m/s

**From velocty diagram:** Velocity of C w.r.t. B -

VCB = vector cb = 1.15 m/s

Angular velocity of Connecting rod ‘BC’ ωCB = VCB / CB = 1.15/0.08 = 14.375 rad /sec

Velocity of slider ‘C’

VC= vector ac = 2 m/sec

## Space diagram 01 Mark, Velocity Diagram 02 marks , Calculations 01 Mark

## Numerical Problem-A casting weighing 9 kN hangs freely from a rope which makes 2.5 turns ............

**Given: W= T1= 9 kN =9000N, d= 0.3 m, N = 20 rpm , µ= 0.25**

**(i) Force reqd.** **by a man**

T2- force reqd. by man

As rope makes 2.5 turns,

Therefore angle of contact ,

θ =2.5x2π = 5 π rad.

We know that,

**2.3 log {T1/T2}** **= µ θ** = 0.25 x 5 π = 3.9275

log {T1/T2} = 3.9275/2.3 = 1.71 or T1/T2 = 51

**T2 = 9000/51 = 176.47 N**

**(ii) Power to raise casting : **

## Define the following terms related to cams.

**i) Trace point **: It is a reference point on the follower and is used to generate the pitch curve. In case of knife edge follower, the knife edge represents the trace point and the pitch curve corresponds to the cam profile. In a roller follower, the centre of the roller represents the trace point.

## For a single slider crank mechanism , state the formulae to calculate by analytical method – Also state the meaning of each term.

**i) Velocity of slider:**

** Vp = w.r [sinθ + sin2θ/2n ]**

where,

Vp - velocity of slider

w- angular velocity

θ – angle of crank to line of stroke ‘PO’

n- l/r = ratio of length of connecting rod to crank radius.

**ii) Acceleration of slider:**

** fp = w2 r(cos θ + cos2θ/n)**

where, fp – acceleration of slider

**iii) Angular velocity of connecting rod.:**

## Draw the neat labeled sketch of Oldham’s coupling. State its applications.

**Applications:**

An Oldham's coupling is used for connecting two parallel shafts whose axes are at a small distance apart.

Used to transmit motion and power.