Orthogonally Constrained 3D Schatz Linkage Bar, Evertible Cube

thingiverse

#### Orthogonally Constrained 3D Schatz Linkage Bar ##### Could we name the linkage system “Orthopython”? I came up with this design while playing with Schatz’s Evertible (or invertible) Cube (https://www.thingiverse.com/thing:5089176), in search of a robust version for classroom use. For each bar, the two linkage axes are orthogonal to each other at all times, and any pair has an angle between -90 and +90 degrees. So the system is orthogonally constrained when all joints are fully extended. In this particular design, a six-bar-ring **does not** evert (or invert) itself because of the constraints. However, one can build a **cube belt ring** of the central edges of a cube (when it is held vertically with respect to a main diagonal). One might just as well leave the two endpoints free for a flexible python-like system. **When more pieces are added, the system becomes really interesting**, esp. for young students, as illustrated in the figures. For printing, please keep the bar(s) vertical to avoid using support. A raft is recommended for bed adhesion. The axis-to-axis distance is 50mm. The tight version is 0.2mm less than the regular loose version along the hole diameter. #### References 1. Schatz, Paul (2013). The study of rhythms and technology : the evertible cube : polysomatic form-finding (4th Ed., P. Carline, Trans.). Niggli Verlag. 2. https://www.thingiverse.com/thing:5089176