Contraptor - sliding element

This thing is a part of Contraptor - a DIY open source construction set for building Cartesian robots: http://contraptor.org

Sliding elements slide on perforated angle http://www.thingiverse.com/thing:1066, driven by either leadscrew or belt. There are three sizes of the sliding element: 3.5\", 2.5\" and 1\". The part list is for 3.5\" size.

Sketchup source:
http://sketchup.google.com/3dwarehouse/search?q=contraptor+sliding-element