Air Valves in Basketballs

[CS]

Can't figure how they work. link My theory is that they are naturally constricted, and only allow passage of air once they are forced open. One observation I've made is when drilling a hole in a sheet of rubber and the hole shrinks to a diameter less then before.

Any thoughts. These would be nice to make out of sheet rubber or something similar. Possibly a construction method?

[PaperNinja]

It's like a trapdoor type rubber flap, pushed open by the needle.

[jimmy101]

I suspect is is just a short length of small id rubber hose inside the ball. The pressure in the ball collapse the hose. An inflation needle forces it open.

[jrrdw]

"How It's Made" at sciencechannel.com/howitsmade did a show on it. I only seen the advertisement and missed the episode...

[CS]

How it's made, one of my favorite shows. I like the older episodes with the funky music.

My bet is it isn't going to reveal the mechanical concepts of the valve. How it's made - footballs, shows nothing of how it works.

For starters I'm gonna heat a needle and peirce a peice of rubber. It'd be nice if it returns to a undetecable hole.

[Doctore]

It is a hole with a flap on the inside. The flap closes when pressure is pushing out but opens when you are pumping.

Or it is like funnel.The pressure keeps the funnel tip compressed and sealed.

http://imageshack.us/photo/my-images/209/funnel.gif/
something like this

[jrrdw]

I'm gonna heat a needle and peirce a peice of rubber

That will melt the rubber and make the hole the size of the needle. There is another show the basket ball may have been on, "How Do They Do That" also on the science channel. Another of my favorite shows along with "Factory Made" and "Ultimate Factories".

[MrCrowley]

Could make an interesting fill-valve, hopefully you do some experimentation with them

[CS]

Cut open an old basketball yesterday.

It is definitely not a trap door flap. As far as the pressure within the ball collapsing on the exterior, I don't think that is the case. It is encased within a relatively large and rigid outer covering. Considering the ball can remain inflated at low pressures. Pictures may come later...

3/4 of the interior looks just like it does from the outside, a hole. At the end it looks as if it has been sliced with a razor. Oddly similar to how the penis is structured.

[Zeus]

I think it's time to name this type of valve. Any ideas?

[Technician1002]

Interesting analogy. Having seen one, they are a small ball of rubber that is cut with a slot that remains closed until a needle from the outside slides into it opening the halves. The opening on the outside is small to act as an o ring on the needle to prevent leaking when the needle is in the ball. Otherwise it would leak.

A search brought up a photo of the valves. The slit is not easy to see in the photo.


This graphic shows the slit on the bottom image. They are cut straight across the end as shown.