作者: Charles E. Gross
DOI:
关键词: Vertical distance 、 Engineering 、 Structural engineering
摘要: A collapsible and retractable step apparatus having first second steps is provided. The are extendable from, used in combination with, a shelf that resides vertical distance above floor. support suspension leg unit free at end thereof rotationally secured to the step. also location between ends of unit. positions supports configuration which positioned along with substantially contiguous plane. rotatable about orientation respect In configuration, or rests on floor such suspends parallel mounting for operatively receiving configuration.