Mechanical engineering project - Water operated
lift bridge - Mumbai
Posted on: 06-Jul-2013
VERTICAL LIFT BRIDGE
This project is a model and a simplified version of Kattwyk Bridge and has been made under the constraints of space, time and resources available.
The Bridge mechanism has been divided in three sections. The central section lifts above, while the two side parts remain intact with the Bridge supporting frame
The lift mechanism used for the bridge is based on the balance beam with pulley system involving four pulleys and counter weight arrangements.
Movable part of bridge section is connected to Counter weight on each side using a wire rope String passing over Pulley mounted above fixed structure.
Track guides wheels mounted on Movable section of Bridge restrict the motion of central section allowing only the motion only in vertical direction to occur and provide the stability to the bridge structure.
The mechanism used to lift the central section by difference of weight is due to the constraint of not using any electric motor or gears but using water for lifting the bridge. In real case situation, the power can be given by electric motors and cables can be used.
SPECIAL FEATURE OF MODEL
- As the weight of Bridge is balanced by Counter weight, we need to Add / Drain some water in water tank to have some difference in total weight balanced by Pulley fixed on Bridge Supporting frame structure.
- Some weight difference as stated above is required to overcome frictional forces.
- We have considered following data for our calculations
Weight of Lift Bridge (with empty water Tank) = 12 Kg
Total weight of Counter weight = 12.50 Kg
When we fill 1.0 L of water in tank, Weight of Lift Bridge will be = 12. 1.0 = 13.0 Kg
- Thus when Water Tank is empty Weight of Lift Bridge < Weight of Counter weight Resulting Bridge will be UP
- Similarly when Water Tank is Filled
Weight of Lift Bridge > Weight of Counter weight Resulting Bridge will be DOWN
- Even the weight difference as mentioned is high, we will minimise weight difference using Pulley with antifriction bearing to save power.
- Safety latch will be used to lock the bridge in Position Safety latch will be fixed on bridge support structure.
- Rubber Bumper are placed below Lift structure and Counter weight to absorb any shocks during lowering of Bridge / Counter weight.
SAFETY FEATURE OF MODEL
- Rubber Bumpers are placed below Lift structure to absorb any shocks during lowering of Bridge.
- Safety latch used to lock the bridge in Position
- When Bridge is in lifted position, Counter weight plate will act as barricade on Fixed part of bridge to prevent any Road traffic.