A wheelchair-bound person is restricted from performing many day-to-day activities primarily because he/she is seated at a specific height all the time. If there was an opportunity for the person to raise or lower the seat at will all by himself/herself, the quality of life would improve significantly. This project aims to create an economical, affordable, self-elevating, always functional (mechanically powered) wheelchair that can be raised to a desirable height for a better quality of life.
Research
The hydraulic technology forms the basis of the proposed design of the elevating wheelchair. Elevating wheelchairs that are available today use very expensive materials to make the wheelchair self-elevating. It is not affordable for most of the general population. And it is totally out of reach for people living in poorer countries.
Hydraulics technology is widely used in a variety of day to day areas. From toy water pistols to heavy engineering machines like cranes and diggers, from car brakes to elevators(certain variety), all use hydraulics as the underlying technology. The principle is simple. Using the incompressible property of a liquid, and the law of conservation of energy, a small pressure at one end is converted to a large pressure at the other end.
The science behind hydraulics is called Pascal’s principle. The liquid in the pipe is incompressible and the pressure must stay constant all the way through it even when pushed hard at one end or the other. The pressure is defined as the force acting per unit of area. If a small force is applied onto a small area at one end, there must be a larger force acting upward on the other end to keep the pressure equal. This is how the force becomes magnified.
Another way to explain would be via the law of conservation of energy. If one end is pressed down quickly on one end with little force, the plunger on the wider end rises slowly with a lot of force. The amount of energy used to move the plunger is equal to the force multiplied with the distance moved. If the water pistol produces twice as much force at the wide end as supplied, it can only move half as far. This is because the energy supplied by pushing down is carried around the pipe to the other end by the incompressible liquid. If the same amount of energy has to move twice the force, it can only move it half the distance in the same time. That is why the wider end moves more slowly than the narrow end.
Scissor Lift technology is one technology that fits in well with Hydraulics. In fact, hydraulics powered scissor lift is very widely used in the world today. The main advantages of a scissor lift are:
- Compact design – very important to keep the design portable and simple
- Weight is distributed evenly – very essential for someone on a wheelchair
- Force can be applied in the direction that is most convenient to get the vertical lift – very important for someone sitting in a wheelchair.
