An interesting product idea that could be an answer in some situations. Here are the descriptions from a couple of YouTube videos posted by the manufacturer. See more at www.lift-u.com
"The Accessor Convertible Walkway (ACW) is designed to provide access where building conditions will not permit the use of a permanent ramp or lift. The initial design intent was to provide access to buildings in older areas of many cities that, heretofore, could not be made accessible. The initial product designs were for exterior applications. However, a number of interior applications have been identified and more are being discovered for this new accessibility solution.
For more information, visit www.lift-u.com or call 209-838-2400.
*General Features*
1. Surface mount—no pit required.
2. Thin stowed profile—less than 1-inch thick.
3. Platform parks in the horizontal position until needed.
4. Counterbalanced for power drive efficiency.
5. Operable undercarriage closeouts.
6. Standard slope is 1:12 unless the application dictates otherwise (i.e., space constraints).
7. 1:18 tapered threshold on 3-sides"
See the convertible ramp here.
"The Accessor Convertible Walkway (ACW) is designed to provide access where building conditions will not permit the use of a permanent ramp or lift. The initial design intent was to provide access to buildings in older areas of many cities that, heretofore, could not be made accessible. The initial product designs were for exterior applications. However, a number of interior applications have been identified and more are being discovered for this new accessibility solution."
See the convertible walkway here.