US Patent 10227221 Lift assembly systems and methods

A lift assembly includes an article to be lifted between a lowered position and a raised position, a drive element coupled to the article, a power mechanism coupled to the drive element, and a power transfer mechanism coupled between the power mechanism and the drive element. The power transfer mechanism includes control electronics having a first upward limit switch adapted to deactivate the power mechanism when the article is lifted to a first upward height, and a second upward limit switch adapted to deactivate the power mechanism when the article is lifted to a second upward height higher than the first upward height.