A lift mechanism for lifting a wheelchair compartment from a non-horizontal ramp position to a horizontal safe position comprises an elevator structure, a wheelchair compartment configured to hold a wheelchair and rotatable from the ramp position to the safe position, a cam connected to the compartment and comprising a cam contact surface, a cam arm connected to the elevator structure and rotatable about a pivot pin, the cam arm having a first side and a second side opposite the first side relative to the pivot pin, an actuator connected to the elevator structure and the first side of the cam arm and configured to rotate the cam arm relative to the pivot pin, and a cam arm bearing pin connected to the second side of the cam arm and configured to press against the cam contact surface of the cam.
