SpudFiles

I know that some people have attached springs directly to the handles of ball valves, but I'm using a different method, and am wondering if others have tried it.

The spring is connected to a weight which is then tied to the handle of the valve, and only after the weight has travelled a bit does it pull on the handle. It yanks the valve mostly open, but it is stopped before the end, in order to not damage the valve. The weight is held in place with a bolt-lock mechanism.

I'd show a picture, but it's not so nice looking, since it is my first cannon. I'm thinking of making a nicer one with a similar mechanism.

show it! the cannons are usually made for power, not looks, anyway. I don't quite understand.

Pretty, shmetty. (in other words, I don't care about looks
If you are really that ashamed of it, a diagram would be nice. Probably nicer than an acctual picture, at least for explaining the concept.

That said, a couple questions:
1) Is the weight sliding in a track?
2) If so, how do you reset it?
3) is the weight connected to the handle of the ball-valve by a string, or what?
4) how strong is your spring, and what size ballvalve is it operating?

From the way you discribed it, sounds like a bell crank set up.

okay, here's a diagram:



The weight doesn't slide in a track except for the very beginning, but my next one will have a complete track. The spring is from a desk lamp, and the valve is 3/4 inches.

The purpose of this setup is so that the weight pulls the handle only when it is going at a fairly high speed, which is why the string from the handle to the deadbolt weight is loose when the deadbolt weight it is in its housing. It also allows me to use a relatively weak spring to move the valve, too.

Not in this diagram is a catch for the weight to make sure that it doesn't put too much stress on the valve itself after the valve is almost fully open.