Hi all,

... as discussed here: [forums.reprap.org] - it seems to be extremely easy to build parallel-kinematic 3D-robots with string-mechanics.

Look especially at Alex Joni's Toy: [wiki.linuxcnc.org] -- and Koppi's Toy: [wiki.linuxcnc.org]

What's here actually not included, would be the third axis - for this i thought about making an elevated platform, moved by strings too, but it would swing around, if not feeded properly ...

So i had a much better idea: - instead of strings for elevating a Z-platform simply use roll-up screens or roller blinds arranged in a triangle, so they would support each other -- so the platform is moved vertically freely by synchrone rotating the blind-axis, but cant's swing around, as every sideway freedom is blocked by the other two blinds ...

So i think to plan/construct a 2 meter high coarse string-tripod-fabber with nearly 2 meter diameter too, where the toolhead runs head-down (magnetically aligned) under an iron-plate fixed to the ceiling and the fabbing base-plate can be lowered by rotating the three aligned blinds, so i have the full height of the blinds but can 'hide' the fabber completelly through winding up the blinds - then only the bottom is visible ...

Viktor