2. CONTENTS:
• Basics
• Single block brake
• Double block brake
• Pivoted block brake
• Self energizing and self locking brakes
• Problem
• solution
3. BASICS FOR BLOCK/SHOE BRAKE:
l = pivot to force applied distance
x = wheel center to pivot distance
Ft = Tangential force
Rn = Normal reaction
2θ = Angle of contact
a = Ofsett distance
2𝜃
7. SELF LOCKING & SELF ENERGISING
𝐴 = 𝜋𝑟2
Self-locking brakes self-energizing brake
x ≤ μ.a & P=0 vs P≠0
8. PROBLEM:
• Given conditions: Eric’s weight as 80kg and weight of cycle as
10kg, driving speed is 20km/hr on a level road and front wheel
diameter is 0.75m. Pressure applied on brake is 150N with
coefficient of friction 0.6.
• To find:
1. distance travelled after application of brake?
2. No of revolution made?
9. SOLUTION:
• Velocity = 5.56 m/sec
• Total mass = 90kg
• Work done against friction= K.I energy of bicycle
• frictional force X distance= K.I energy of bicycle
0.6 × 150 × 𝑠 =
1
2
× 90 × 5.552
Stopping distance = 15.44m
10. SOLUTION Part 2:
• Distance travelled in one turn = circumference of wheel
• 𝜋 × 𝐷 = 3.145 ×
0.75
2
• Circumference = 2.3561m
• ∴ 𝑛𝑜 𝑜𝑓 𝑟𝑒𝑣𝑜𝑙𝑢𝑡𝑖𝑜𝑛 𝑚𝑎𝑑𝑒(𝑁) =
𝑡𝑜𝑡𝑎𝑙 𝑑𝑖𝑠𝑡𝑎𝑛𝑐𝑒 𝑡𝑟𝑎𝑣𝑒𝑙𝑙𝑒𝑑
𝑐𝑖𝑟𝑐𝑢𝑚𝑓𝑒𝑟𝑒𝑛𝑐𝑒 𝑜𝑓 𝑤ℎ𝑒𝑒𝑙
N = 6.535
N ≈ 7 𝑟𝑒𝑣𝑜𝑙𝑢𝑡𝑖𝑜𝑛𝑠
11. REFRENCES:
• https://upload.wikimedia.org/wikipedia/commons/1/1b/Labeled_brake_set_mono
_2.jpg
• http://i.ytimg.com/vi/JHBlIsmWPYA/maxresdefault.jpg
• https://upload.wikimedia.org/wikipedia/commons/thumb/1/1b/Labeled_brake_set
_mono_2.jpg/400px-Labeled_brake_set_mono_2.jpg
• http://eorailway.co.uk/departments/diary/uploaded_images/Mk2-TSO-Replaced-
Brake-shoes-22_Nov_2012.jpg
• http://thumbs.dreamstime.com/x/train-brake-11494344.jpg
• http://www.railway-technical.com/Brake-Discs.jpg
• https://upload.wikimedia.org/wikipedia/commons/8/80/Bicycle_caliper_brake_hig
hlighted.jpg
• https://upload.wikimedia.org/wikipedia/commons/8/8d/Bicycle_brakes_-
_animated.gif
• http://www.railway-technical.com/airbra-app.gif
• TECH MAX publication book on “ THEORY OF MACHINE 2”
