Heres your hook that auto disengages. Simply have to determine your pivot point in balance so that it will tip forward when no load. Then the square tube slits are staggered in length so that the flat bar is stopped at the back, not passing through. This keeps the flat bar primed for forward disengagement. The sq tube only lòng enough to incorporate a hoop on top to fix the rope to. A bit of playing to find correct pivot point on hook.....