For a homemade fitness equipment I need to attach a bar to a door frame without using screws or modifying/damaging the doorframe. The only idea I had was to use a pullup bar which one can clamp into the door frame, something like this
The problem is that the bar has to be heavy duty anchored, say it should be able to hold forces equivalent to min. 120 kg in each direction. I don't want a solution where something is anchored in a closed door!
The project was inspired by this YouTube video and this YouTube video but will be a bit more complicated. I sketched a basic example how it will be used in the second image below (however the device will become more complicated and powerfull, but the problem of anchoring it in the doorframe without closing the door remains the same).
Edit: The solution (once built) should be easy to mount and unmount in just a few minutes.
Edit: The top bar on the second picture is not the (main) problem. There I can use my other pull up bar (Iron Gym) which is more secure and heavy duty but which I can mount only on the top of the doorframe so it doesn't help with the bar on the bottom.