Project ForgeMachine Design
Design Against Static Load
GATE 2016
Hard
For a pivoted brake shoe pressed against a rotating drum by a lever with the pivot below the shoe and the actuating force applied above (as in a standard single-shoe drum brake), which one of the following is TRUE?
- Self energizing for clockwise rotation of the drum
- BSelf energizing for anti-clockwise rotation of the drum
- CSelf energizing for rotation in either direction of the drum
- DNot of the self energizing type
Explanation
A brake is self-energizing when the friction force at the shoe-drum interface creates a moment about the shoe's pivot that assists (adds to) the applied actuating force, reducing the force needed to hold the brake on. For this lever/pivot geometry, that condition is met specifically for clockwise drum rotation.
Source: GATE ME 2016 Set-2 (2016)
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