LifeTrac Quick Connect Wheel Challenge Results

We put up a crowd design challenge at GrabCAD a few weeks ago – for LifeTrac IV – Quick Connect Wheels. The basic problem was: how do you design wheel assemblies for a tractor that can be taken on and off in under 5 minutes – for interchangeability or repair. We have gotten a number of excellent contributions – see results – and we are picking the design by Marcus as the winning choice:


The design is OSE Specifications-compliant in its simplicity. Two pins are required to remove the wheels. Stock 1/2″ mild steel is used throughout, with minimal fabrication. My only question is pin alignment, but if they are tapered, they can be punched in and out easily – as they are readily accessible. If there is any looseness, a cam can be added readily to the pins, to tighten the assembly against the frame. Moreover, it would require to a holding mechanism to hold this in place as the pins are inserted – so just one person can take the wheels on and off. All these issues are readily implementable.

So Marcus will be receiving a GVCS and GrabCAD t-shirt – and an invitation to the Build Naturally Workshop. Marcus may even get a chance to ride in the upgraded LifeTrac that he helped to design – and lay bricks in the Hybric CEB microhouse:

We have already began prototyping the quick attach wheels for the tractor – expected to be finished by Jan. 2. This is an older design, worth trying as a baseline. So far it appears to be working well, and may be modified based on the other GrabCAD ideas.

GrabCAD is proving to be an excellent platform.  It stretches one’s imagination – providing a diversity of concepts from around the world. While ideas were slow to come in at first, they pulled through at the end. I am amazed at the amount of time that the 14 contributors spent. The other entries provide excellent design ideas – and deserve refactoring on the OSE wiki as meaningful contributions to LifeTrac development. They provide ideas that should be studied at the very least, and some of the other quick attach wheel models or parts thereof should be built as well.

An interesting revelation for me is that the Quick Connect Wheel is an implementation of the Universal Rotor.  Therefore, solving the quick connect wheels also solves the Universal Rotor design.  That is a great example of the modularity – brining us closer to the life-size Lego set for real machines.

We also have the Ironworker Machine up as a GrabCAD challenge – and I look forward to tapping more talent via GrabCAD as we hit the ground running in January.  Some projects that lend themselves to ready design are the pelletizer, pellet gasifier burner, backhoe, bulldozer, truck frame – anything with not too much complexity. There should be a platform like this for electronics as well. Happy New Year.


  1. Taulant

    >There should be a platform like this for electronics as well.

    You might be interested in

    They might be compatible with the entire OSE philosophy.

    My guess is that the first prototypes of functional and useful circuits will show up towards the end of 2012.

    Taulant Ramabaja

  2. […] about the quick connect wheels on the wiki. We just ran a successful design challenge on these, discussed in the last post. We have the whole fabrication process as a series of YouTube clips totaling 15 minutes (anyone […]

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