Help! > Specific Engine Help
Bell Cranks
PaulR:
Bit of a necro post but I'm still cogitating on this one!
I'm thinking of adding links to both sides of the bell crank. In this diagram showing a plan view, link 1 is straightforward as the bell crank and the valve are moving in the same plane but what about link 2? Am I right in thinking the holes at each end should be 90 degrees apart ie one horizontal and the other vertical? And would anything be needed to keep the valve rod parallel to the cylinder bore? Any help appreciated ;D
steam guy willy:
hi could you use a revolving centre rod with an off centre pin rather like an eccentric that is free to line up automatically ??!! :popcorn: :popcorn:
PaulR:
--- Quote from: steam guy willy on May 11, 2026, 08:14:21 pm ---hi could you use a revolving centre rod with an off centre pin rather like an eccentric that is free to line up automatically ??!! :popcorn: :popcorn:
--- End quote ---
Umm, sorry I don't understand :headscratch: Can you explain a bit more?
crueby:
What you are trying to accomplish is what a ball joint does - move in two axes without having the links collapse in the center. The picture you showed earlier was a ball joint. This page shows another way to construct it, first picture below the table of contents list at the top:
https://www.theengineeringknowledge.com/what-is-a-universal-joint/
PaulR:
--- Quote from: crueby on May 11, 2026, 09:29:17 pm ---What you are trying to accomplish is what a ball joint does - move in two axes without having the links collapse in the center. The picture you showed earlier was a ball joint. This page shows another way to construct it, first picture below the table of contents list at the top:
https://www.theengineeringknowledge.com/what-is-a-universal-joint/
--- End quote ---
Thanks Chris, yes I see now that a simple fixed two axis solution won't work, as it needs to allow a combination of movement in those axes. I guessed that the picture showed a similar joint but I can't quite see how that one works. Either way, it's way beyond my ability to make so I'll have to use the original idea with some slack in the joints or come up with something else.
Navigation
[0] Message Index
[#] Next page
[*] Previous page
Go to full version