| 摘要 |
A foldable ramp having a first, second and third rectangular sections contiguous with each other and defining a ramp path having longitudinal and transdermal axes. A first hinge group is affixed to both the first and second sections and a second hinge group is affixed to both the second and third sections. The first hinge group has a first axis of rotation on the upper side of the ramp path and extending across the longitudinal axis, and a first rotational range of slightly more than 180.degree .. The second hinge group has a second axis of rotation on the under side of the ramp path and extending in a parallel alignment with the first axis of rotation, and a second rotational range of slightly less than 180.degree.. The f irst and second hinge groups each have a central hinge and outside hinges, and stoppers on the central hinges to limit the rotation of the central hinges a few degrees less that the rotational range of the outside hinges. This configuration causes the ramp to arc longitudinally and transversely upwardly when deployed for increasing the moments of inertia of the ramp.
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