Hydraulic Car Lift

We all have heard about Hydraulic lifts sometime in our life, but some of you may think that how it works or how to build one for ourselves.

Today we are going to discuss about lifting cars using Hydraulics, which is based on Pascal concept.

Why understanding Hydraulics important?
Hydraulics is a topic in applied science and engineering dealing with the mechanical properties of liquids. Fluid mechanics provides the theoretical foundation for hydraulics, which focuses on the engineering uses of fluid properties.


Concept:
Pascal's law states that the pressure applied at one point of the liquid is transmitted equally in all direction. This principal is applied in hydraulic lift, for lifting heavy objects.

We know 

Force = Pressure x Area

Therefore Pressure = Force / Area

P1 = P2 (if pressures are equal throughout).

Formula becomes F1/A1 = F2/A2

Using above formula we can lift heavy materials using little force. For e.g. here we are lifting 10 pound using 1 pound.

1 pound / 1 square inches = 10 pounds / 10 square inches

So, to lift a car we should produce force(F1) which is more than F2(car force)

F1(force applied)
F2(Car force)
A1(Area below F1)
A2(Area below Car)

F1/A1 = F2/A2

F1 = F2 * A1/ A2

Therefore value of F1 is dependent on A1/A2 Ratio. Lesser it is lesser the force required by us.


 
Related Links :

How Hydraulic Machine Works ?

Fluid Power (pdf)