Very good concept with completely free door movement in case of no wind. Easy to integrate and no electrics or hydraulics involved.
Also good concept, compact design and very nice presentation.
Interesting idea for a damper with transfer of rotation into axial movement, also compact but will require some further research and could be prone to oil leakage.
Simple and elegant but will require further investigation and design.
Could be more elaborate, but interesting idea to give the door a different movement thus avoiding door slamming entirely.