That was very well explained and very helpful. I am a little taken back at how large the spring needs to be though. Perhaps the torsion spring is not the solution as I only have 50mm of room on the pin.
Sorry for the very late reply, I appear to have skimmed over my email notification.
You are right about the weight on the arm that it is mostly at the end of the arm.
Once up there doesn't have to be much force on the arm, only enough to stop it moving (rattling).
Yes the spring needs to fit...
I have a 50mm square tube arm approximately 600mm long coming off another piece of square tube (sitting horizontal) pivoted with a 14mm pin. At the end of the arm there will be about 25kg. The arm will sit vertical which is 90 degrees, and it will swing down to about 190-200 degrees. What I need...
