Paul Hovnanian P.E. wrote:
Basement, Ground, 1, 2, 3. Five levels, four rises between them. I haven't been to the Science Museum for several years, it's not what it used to be, but I do remember looking at these pistons, and not being able to see a joint in them. Most of the lifts of this type that I see link just two or three levels. I've never seen a telescoping one, but it would make sense. I've seen telescoping hydraulic rams used for other purposes.