Researchers from Georgia Tech and Emory University have created low cost energy recycling stairs that can be added on to conventional staircases. There is a spring based mechanism in the steps that save the energy when someone walks down the stairs, and recycles that to assist those walking up the stairs. The stairs reduce the stress on ankles by up to 27 percent when someone is walking down, and make it up to 37 percent easier for someone walking up.
Each step sinks slowly along with the person, and locks into place on the next level. The stairs stay in the same position till someone walks up the stairs, when the steps rise in tandem with the individual. The study has been published in PLOS ONE. Karen Liu, a co-author of the paper says, "Unlike normal walking where each heel-strike dissipates energy that can be potentially restored, stair ascent is actually very energy efficient; most energy you put in goes into potential energy to lift you up. But then I realized that going downstairs is quite wasteful. You dissipate energy to stop yourself from falling, and I thought it would be great if we could store the energy wasted during descent and return it to the user during ascent."
The steps are primarily designed for use in homes, where elevators and escalators are too expensive to install. The system works in such a way that the add-on steps can be easily removed if they are no longer required. The researchers did not anticipate a reduction in stress and required energy levels while someone walked down the stairs. The temporary stairs could be particularly useful for the aged, pregnant women, and those recovering from surgery.