[RRLedford]

I suggest that, for rotationally driven trave mechanisms, people always consider using a mechanical, adjustable torque, slip clutch combined with a hard mechanical stop to prevent over travel.

In 2011 we used a single axis, chain driven (by way geared down dual wiper motors) swing arm with rheostat positioning control.
The arm was very long and could not take a lot of abuse, so we needed to make sure if it was moving and hit too much resistance, the motion would stop while the slip clutch just spun, with no further motion to cause damage.

This also worked great for re-synching the rheostat, since with the chain stopped, we could always still swing the arm to any position by pushing the arm enough to overpower the set torque limit of the slip clutch.

Even with micro switches and other programmed means for limiting travel, stuff happens, and having a slip clutch can be a godsend for preventing damage. Combining a rubber bumper travel stop with the slip clutch is all it takes for rotary actuated motion limiting..

-Dick Ledford