The application is a flat sign mounted to a wall outdoors. It may be touched or hit occasionally and I'd like it to "spring back" and not deform the sign or its mounting brackets. Would coil springs or spring steel leaf springs be a better application here and why? Not my image but a similar mounting.
More information, please. How is it going to be touched? By what sort of forces? (Like, people pushing on the sign, or box trucks hitting it?)
If you are thinking of using car parts, id probably go with coil springs, but I'd honestly try to design some closer to what the old hood ornaments did. Spring on the inside of the mount, a sort of nested mount for it to slide back into when messed with.
Gravity Pivot Hinge. Move the sign out of place and it moves up on the hinge, gravity brings it back down to the set position.
Usually used for pool gates, bathroom partitions, A couple of sections of stainless tube and some stainless pins. You would just have to figure out how to limit someone from lifting the sign completely off it's mount.
I agree... more info might help.
I like the gravity hinge idea, but I would be afraid that every breeze would cause it to swing and whack against the building.
Possibly a gravity hinge with pneumatic struts? I'm just afraid you'd have to replace the struts every few years.
I would go spring. If it's getting whacked by college students jumping up and hitting it, use soft springs. If it's getting hit by tractor trailers, maybe a leaf from an F250.
With a gravity hinge - cool idea - you could probably fine tune the resistance to movement with mass. The heavier the sign, the more it will resist getting bumped off center.
I like the gravity hinge. Alternatively, I made something similar for my mailbox after plows took it out for the 10th time... I made an arm for the mailbox, welded small exhaust u bolts to it and loosely clamped them around a conduit post. It isn't self resetting, which would probably get tiring if someone needs a ladder to reset it. But, it's working great as a mailbox post.
I hadn't considered a gravity hinge. The sign would be low enough and close enough to a street that it may be brushed by jumping kids or a box truck. Where I'm at is pretty windy and I'd like the sign to not move in the breeze but also not require a "reset" if it got bumped. 25 lb weight and 30" square.
Don't underestimate how hard a windy day will try to move 900 in². I mean, you just mentioned it, so I don't think you are underestimating it, just imagine holding that panel out the window at 25mph.
I like the gravity hinge idea, and you could also preload it with a spring assisting in the same direction as gravity if you didn't feel like that was enough centering force. Easy to add as a part of capturing it against being lifted off if the hinges don't come with a capture?
Part of what appeals about the gravity hinge, I think, is that I'd have thought you'd want the spring to be holding the sign static against some sort of reference surface as opposed to literally mounting it on spring. With the latter, any force will result in motion, and by the time it's stiff enough not to wobble in the breeze it's going to take a lot of force to move it out of the way of whatever hit it. The gravity hinge makes the reset force constant (if you ignore me and my preload spring) and the upset force proportional to the mass and ramp angle. It should sit pretty solidly in the base of that V until it's disturbed.
Which is a really long way of agreeing with someone else's idea, but I had fun.
What about suspending it from the top so gravity has more effect? You could make an "L" bracket out of tubing and have the sign slide over it with a larger ID tubing inside it.
I guess it would depend on what direction the swing needs to be to be most helpful.
You could also cut a couple mounts out of a leaf spring.
Stainless Steel Adjustable Double Acting Spring Hinges. Hard to say how much tension can be applied to the hinges but you could always add more as needed. They seem to come in 4, 5, and 6" sizes.
The sign in the picture looks like it works. Do it that way.
Gravity hinge with a coil spring on one or both pins to hold it tight enough to resist wind. Gotta do the calcs, I would figure on force being applied by a 50 MPH wind breakaway to give yourself some cushion for the pushin.
And then you gotta make sure the other mounting points are rigid enough to resist this force, and that the sign is strong enough or has a crash cage/exoskeleton to avoid being whacked by a box truck and just folded up.
Are there other signs in this same corridor/location that have a fix to them? Otherwise this seems like a solution looking for a problem. I was an absolute hellion of a college kid and have been known to drive a box truck or 2 and still never took out a sign like this.
How about a hanging sign? Use the spring loaded double action hinges to dampen and stabilize it in gentile winds. A chain as a secondary safety backup.
If kids look up and see it's mounted on springs, they may be more likely to jump up and bang on it.
In reply to VolvoHeretic :
No no no, that's not complicated enough!
In reply to Keith Tanner :
I'm pretty sure with just a couple more iterations we could have a Penske coilover inboard the sign body with linkage actuation...
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