With the loading mechanism sorted, the next trick was the center loading crane. While it's not used to load the conex, it can be used to load stuff onto a flatrack.
This uses more linear actuators to lift up and down
and then another to move the arm in and out, with a 9G continuous rotation ("sail" or "winch"), with a little drum on the end to spool up the cable (well, string
)
That all in turn is mounted on a skateboard bearing, with a 3D printed worm gear assembly driven by a regular size winch servo, pink and purple in the mockup. I find it handy to use the proper colors (ie olive drab) for parts which are "done" and then obnoxious colors for the parts I'm working on to more easily locate them.
and in the real world, getting a cat scan. Projects in this house get a lot of cat scans.
Actually setup, down:
and then checking clearance over the hook:
With moving parts like this, geometry comes into play more than I'd like. Turns out that when the crane is lifted so it clears the hook, the reach is reduced. As mentioned, ended up with a switch to choose one of three crane positions, one with reduced height but at an angle to give maximum reach. It will rotate over about 270* of the cab, and drop loads into the flatrack to about half the length back.