For those of you who are interested in replicating LifeTrac II – the second prototype of OSE’s open source tractor – here is the fabrication documentation that we have so far. This is meant to be used by dedicated co-developer-builders, who can contribute to improving the design. We still have to build Prototype III, and we are planning on the Full Product Release of LifeTrac on May 1, 2011. This would be after we complete Prototype I of the CNC torch table , which we will use as part of our digital fabrication optimization to cut parts for the tractor – thereby saving many hours of time per build. Right now, we need a design for an open source stepper motor controller suitable for the CNC torch table, as an open source version of the controller does not yet exist. As far as other open source fabrication optimization that we are contributing to RepLab, the Open Source Fab Lab – we are now using our open source 150 ton hole puncher and heavy duty hydraulic drill press quite successfully as part of every-day operations. These are all contributions to a low-cost tooling infrastructure for a serious open source, flexible/digital fabrication workshop. We look forward to the day that we could build all of these from scratch – by starting with scrap metal and an induction furnace.
For the tractor, start with the 3D design drawing in Blender, which is not just a pretty 3D image – but an exact model of the build that can be used exactly as is. The fabrication procedure of the tractor is documented on the wiki.
Two years ago we proposed the quick attach plate lever mechanism for the Quick Attach plate on the tractor, which we never implemented on LifeTrac I for lack of time. Instead, we just used pins to lock an implement in place, as seen in the last link. Now we have the working lever, which is much quicker to engage, and is worth replicating as a useful, open source mechanism. See the fabrication procedure for the quick attach plate and latching lever:
The design drawing is downloadable at our design repository:
There is one known bug at this time – we need to shorten the wheel base by about 12-18 inches – to make turning easier. Other than this, watch the tractor rumble:
We are finishing the Power Cube II and Soil Pulverizer II, and we’ll report on these next.