Toys, Garden Trellis and Other Research by Special Structures Group, Department of Engineering Science, University of Oxford

The simplest motion structure is usually a linkage made from rods and hinges. Under certain geometric rules a single expandable unit can be repeated to create large-scale structures that can be folded into different configurations. Therefore, expandable units and a geometrically harmonious connection method are two key factors in creating a motion structure. Common examples of this type of structure include trellises and lazy tongs, which are made from planar scissor-like elements. All of these are essentially planar assemblies. Real 3-D structures with full geometrical compatibility are rare.

We have identified a particular arrangement for many planar 4R linkages so large motion structures with enclosed loops can be created. We also identified a way of generating grid like spatial motion structures capable of forming arches and spiral profiles. All of the components of the assemblies move harmoniously during expansion.

Please contact us for details if you are interested.