| 摘要 |
A loop-assembly is disclosed which is comprised of at least three scissors-pairs, at least two of the pairs comprising: two essentially identical rigid angulated strut elements each having a central and two terminal pivot points with centers which do not lie in a straight line, each strut being pivotally joined to the other of its pair by their central pivot points, each pair being pivotally joined by two terminal pivot points to two terminal pivot points of another pair in that, (a) the terminal pivot points of each of the scissors-pairs are pivotally joined to the terminal pivot points of the adjacent pair such that both scissors-pairs lie essentially in the same plane, or (b) the terminal pivot points of a scissors-pair are each pivotally joined to a hub element which is small in diameter relative to the length of a strut element, and these hub elements are in turn joined to the terminal pivot points of another scissors-pair, such that the plane that one scissors-pair lies in forms an angle with the plane that the other scissors-pair lies in, the axes passing through the pivot points of one of the scissors-pair not being parallel to the axes of the other scissors-pair, where a closed loop-assembly is thus formed of scissors-pairs, and this loop-assembly can freely fold and unfold without bending or distortion of any of its elements, and a line that intersects and is perpendicular to the axes of any two terminal pivot points is non-parallel with at least two other similarly formed lines in the assembly, the angles formed between said lines remaining constant as the loop-assembly is folded and unfolded.
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