Basically this is a redesign of a suction cup ball.
Standard suction cup balls work pretty well at sticking to flat surfaces but they're a bit goofy. They have these discrete suction cups mounted on arms that radiate from a central point so it doesn't feel like like a ball.
Anyway, I've designed a more ball-like version.
The new ball comprises a spherical rubber shell (red) with dimples on the exterior and corresponding protrusions on the inside (note: the real ball would have many more dimples and protrusions; I just got bored of adding dimples to the illustration). The ball also has an interior ball (green). (see illustration)
When the ball is thrown against a surface the interior ball pushes the protrusions. Thus gas is pushed out of the dimples and the dimples form suction cups against the surface.-- xaviergisz, May 12 2007 illustration http://imgur.com/a/uKv5T [xaviergisz, May 12 2007, last modified Dec 13 2011] Fishbone! http://images.cb2.c...oapDishBlackF6?$lg$...no...I mean get a better soap dish. [DrCurry, May 13 2007] Geckos http://en.wikipedia.org/wiki/Geckofor [marklar] [neutrinos_shadow, May 14 2007] That sounds like it just might work - interesting idea!
I can see the thumbnails behind the link well enough, but when I actually click on them to see details, I get "access denied / account disabled". Since your account still exists, that's obviously not true - but what's going on?-- jutta, May 12 2007 I think the dimples would have to be larger for this to work. Weight balance would be tricky: too little mass for the inside ball and it won't stick; too much and it will break suction on the rebound.-- nuclear hobo, May 12 2007 I also suspect that it would fail for another reason.
A traditional (Medieval, say, or pre- Raphaelite) suction cup works because the load is placed centrally (in this case, on the "stalk" that attaches to the back of the cup). The easiest way to release a suction cup is to lift up the edge of the "skirt" and let air in.
Imagine your ball stuck to a vertical surface: the weight of the ball will be pulling directly on the edge of one (or more) dimples, and will therefore lift their edges and release the suction.
In other words, your design is a sort of "self-releasing" suction ball.-- MaxwellBuchanan, May 12 2007 thanks jutta. I've deleted the first illustration which seemed to be causing the problems.
I admit it probably wouldn't stick to surfaces as effectively as a normal suction cup ball. This could be seen as an advantage; the ball sticks only temporarily but doesn't get stuck onto surfaces.-- xaviergisz, May 13 2007 DrC, cool soap dish. what's the relevance?
Now I'm thinking about it, maybe a sticky glove is a better application for the mini-suction cup idea.-- xaviergisz, May 13 2007 //a sticky glove// Yes, I think that would be good. I can imagine its being useful and fun. More generally, this dimply sheet could be made into a range of garments. [+]
One suggestion: if it were possible (may not be) it would be better if each "dimple" had a small "lip" extending outwards (radially as well as axially) from its edge. This would be a compromise, but it would give the dimples a bit more of the performance of conventional suction cups (where the load does not act directly on the rim).-- MaxwellBuchanan, May 13 2007 Sounds like a load of old gecko feet to me.-- marklar, May 13 2007 //Sounds like a load of old gecko feet to me// Gecko feet stick using van der Waals forces, not suction cups. This is more a ball of cephalopod tentacles.-- neutrinos_shadow, May 14 2007 The sticking power of a suction cup depends on the area times the partial vacuum inside. Here, the area of each dimple is miniscule, and the likelihood is that only one dimple will touch the surface flat enough to develop a vacuum, so it's unlikely that this ball could support its own weight. It would stick better than a golf ball, but not by much.-- ldischler, May 14 2007 I had envisaged that the ball would be fairly elastic. Thus, shortly after impact, several of the suction cups would momentarily stick to the surface. The suction cups would then successively unstick, until the ball becomes completely unstuck (this might all happen in anywhere from half a second to several seconds).
The large number of small suction cups (as opposed to a small number of large suction cups) might have advantages. For example, it might stick more readily to non-planar surfaces (e.g. your hand).-- xaviergisz, May 14 2007 //I had envisaged that the ball would be fairly elastic. // Then you might want to have the inner ball also hollow, and filled with water or gel...or dispense with the inner ball and fill it with sand. A thin spherical covering dotted with suction cups and filled with sand. That way, when it splats against the wall, it flattens out and stays that way.-- ldischler, May 14 2007 random, halfbakery