Background: Staircases are seen in almost every man-made structure. Many old buildings do not have elevators fitted thereto. The task of climbing stairs is a major challenge for differently able people or for elderly people, due to the impaired mobility.

In the buildings, which are equipped with elevators, power backup facility may fail for certain reason and if emergency arises in the same span, climbing up or down the stairs is not convenient. Carrying heavy loads to upper levels is a difficult task even for a normal person living in the old and high buildings in which elevators are temporarily or permanently not available. Hence ‘Staircase Climbing Wheelchair’ is a need of the day.

The products which are available to cater this need are not at all cost-effective.

This invention provides a new, innovative, simple but ‘affordable’ design of ‘Staircase Climbing Wheelchair’, which can also be extended later into a material transfer trolley.

Innovation: The product developed herein uses specially designed wheels corresponding with the steps of target staircase. Combination of steps of staircase is treated as a ‘Rack’ (straight/flat gear). Shape of matching wheels is obtained by using ‘Gear Generation’ principle. Well-known method of ‘Rack Shift’ is used to ‘Generate’ the wheel profile. Wheels behave like a ‘Pinion Gear’, perfectly conjugate to (corresponding to) the staircase ‘Rack.’

Design of Product: Overall design of the wheelchair is very simple. Apparently it looks like a normal wheelchair but is fitted with chargeable battery, BLDC motor, worm gearbox, chain-sprocket positive drive etc, all hidden under the seat. Two conjugate wheels, designed as per the innovative concept explained above, are fitted onto the power-shaft and are driven via positive transmission.

Working: The person willing to move on the stairs sits on the chair facing downside. Attendant also faces downside from behind the wheelchair, holds the handles and slightly tilts the chair so that the special wheels engage with the steps. He/she puts on the DPDT electric switch in forward /reverse position to move the chair up/down and he/she navigates the wheelchair.

Peculiarity: It is useful for specific building because the design of wheels is based on the step parameters of particular staircase. Hence the configuration is to be used as an accessory of the building and it is to be used in case of total or temporary unavailability of elevators.

Steps followed to reach to the product level: Initially a reduced scale model is developed to verify that it works as per prediction. Full scale four wheeled working chassis is then developed as intermediate step. Finally, the transmission system is absorbed inside the wheelchair, to arrive at an elegant working candidate product.

Conclusive clear statement of novelty: This PATENTED and well recognized candidate product will help the society by providing simple, economical and customized ‘Staircase Climbing Wheelchair/Trolley’ with better maneuverability. It is characterized with substantial societal benefits like capability of saving lives in crucial times, solution to a genuine problem, simplicity in construction and service, low cost etc.