2 Way Ratchet Mechanism or 'Mungomotor'

thingiverse

An alternative to a Z-axis motor in a RepStrap machine could involve using the X-axis to move the boom up and down by traveling to its extremities and engaging a ratchet mechanism. This would entail turning a captive nut 90 degrees with one end push and -90 degrees with the other, resulting in approximately 0.3mm travel on a standard M8 thread. It's also possible to use this as a mechanical stepper motor with the frame driven by a solenoid and gears providing the required step rotation. The noisy and slow nature of this motor has led to its nickname, 'mungomotor'. Although still theoretical, this design can be made using hand tools, laser cutter or 3D printer, and feedback is welcome.