A differential band brake, as shown in fig. has an angle of contact of 2250. The band has a compressed woven lining and bears against a cast iron drum of 350 mm diameter. The brake is to sustain a torque 350 N-m and the coefficient of friction between the band and drum is 0.30. Find: - a) The necessary force (F) for the clockwise and anticlockwise rotation of the drum; and - (b) the value the value of ‘OA’ for the brake to be self locking, when the drum rotates clockwise. -

Mumbai University > Mechanical Engineering > Sem 5 > Theory of Machines-II

Marks: 12 Marks

Year: Dec 2015

$T_B = 350 N-m \\ D = 0.35m \\ r = D/2 = [0.35/2] \\ µ = 0.30$

To find:

1. Force P

2. Distance OA for self locking

Calculating the tension in the band

$θ= 22.5˚ \rightarrow 3.926 rad \\ \dfrac{T_1}{T_2}= e^{uθ} \\ \dfrac{T_1}{T_2}=e^{0.30 \times 3.9269} \\ \dfrac{T_1}{T_2} = 3.9527 \\ …