Try something simpler like MB door locks. Lots of info on those. Or convertible top mechanisms.

If you have access to an entomologist (is that right?), compare the hydraulics in some bug legs vs muscles in mamalian legs.

You might pose the same question to your dentist. Or does your dentist use a Dremel?

I'd like to see a purely mechanical backhoe.

Sixto
95 S420
91 300SE
87 300SDL
83 300SD