BibTeX:

@article{IJIRSTV2I11184,
     title={Transposed Wheelchair with Stair Climbing Mechanism},
     author={SHIBIN P SABU, ROSHAN MOHAN, ROHITH KRISHNAN R, YADUKRISHNAN PS and VAISAKH VIJAYAN},
     journal={International Journal for Innovative Research in Science & Technology},
     volume={2},
     number={11},
     pages={618--625},
     year={},
     url={http://www.ijirst.org/articles/IJIRSTV2I11184.pdf},
     publisher={IJIRST (International Journal for Innovative Research in Science & Technology)},
}

Wheelchairs are one of the only means by which disabled people get to go around places. Developed countries are almost well equipped with the infrastructure to accommodate them, as in ramps and lifts, which accompany stairs. But for developing and under developed countries in Asia and Africa, such facilities are far from reality. In our own country, there are a large percentage of buildings in urban and semi urban areas, built without consideration for accessibility. A normal wheelchair user need to be lifted and carried manually by two more helpers to get to different floors of a multi-storied public building or even their own flats and apartments. One solution for this would be to modify civil structures, but that would neither be economical nor practical. So, the other solution would be to engineer a wheelchair that can ascend stairs. These are available in the market, like SCALEVO, but being the products of Japanese and American research labs, they are aimed at people who can afford such technology; not for the less fortunate majority. What made stair climbing costly for a powered wheelchair, was the complicated wheel motion, and the electronic control systems. So to simplify this we propose a Star Wheel, taking inspiration from the rack and pinion mechanism, and the cluster wheel mechanism. Also, the complex and expensive control systems can be replaced by an even more sophisticated, but freely available human brain, that of the assistant or any helper. The effort for the motion is taken by a 250W permanent magnet DC motor powered by two 12V battery, with high torque (reduction using chain) and the helper need to take care of only maneuvering the device, during the climb up or down the stairs. This same motor can provide powered motion in the forward direction, by reversing polarity, and attaching an auxiliary circular wheel. People with considerable upper body strength would be able to hold the handle, lift themselves and mount on to it. Assistance is required for the old and weak. To solve this, we considered different ideas and found that, by removing the backrest and placing the seat slightly below the average height of a bed, chair or toilet-seat (450mm), with a slight outward slope, the user can simply slide on to it from the back! If he is a very weak person, then he can be helped by an assistant to do so, still reducing the assistant's effort considerably; earlier, the person needed to be lifted manually and placed by him. Thus there is transposed entry to the wheelchair, along with conventional entry. The backrest is locked in place after entering. A two wheel plus one caster-wheel design ensures 3-point ground contact at all time and has a lower tipping angle, also it makes the frame design simple and light. So, three high traction wheels, vibration isolation using suspension and a high torque drive makes it suitable for rough terrain. The frame and drive is made minimal enough to reduce cost, using standard parts as far as possible, and the ability to be assembled, modified and reassembled.

Star Wheel, Stair Climber, Transposed Entry