Patent attributes
An assistance device includes a body having two wheels, and a pivotal device located in the body. Two transmission units are pivotably connected to the pivotal device by two shafts. A restriction unit includes a first link, a second link and a rail which is connected to the body. The first link has the first end pivotably connected to one of the two transmission units. The second link is pivotably connected to the other one of the two transmission units. A roller is connected to the first end of the second link and movable along the rail. A leg having a top end to which the second end of the first link is pivotably connected. The second end of the second link is pivotably connected between the top end and the lower end of the leg. The leg contacts against the ground to lift the body to climb stairs.