Mr. Horse is part or all thoroughbred, isn't a good doer, and needs lots
of grain to keep his weight up.

Mr. Pony (AKA Founder-Boy) is a greedy ******* who could live on
thistles and air, but he's smart and he likes grain. Unfortunately it
makes him fat in the long run, and in the short run it can make him
founder (he's foundered more than once before, so he's particularly
susceptible).

Our feeding stalls are laid out with a shelf about 18" high, for feed,
and a window into the feed bay about 30" high. The windows are high
enough that Mr. Pony can't reach through to get hay piled up on the
floor of the feed bay, but Mr. Horse can.

Recently, Mr. Pony has learned that he can step up on the shelves and
eat all the hay that he wants. Not only does this make him fat (and
more prone to foundering), the shelves aren't strong enough for him, and
he's already punched a hoof through the surface of one of them which
just ain't safe.

So the horses are locked out of the feeding stalls while we ponder.

I'm thinking of replacing the shelves with something akin to a breakaway
basketball basket -- i.e. something that'll handle the strain of Mr.
Horse licking the thing clean, but will collapse when Mr. Pony tries to
stand on it.

But I need a latch -- I'm thinking that a good strong magnet working on
an iron strap would work, but would attract crap. Alternately,
something akin to a BIG cabinet latch would do.

It has to support probably between 20 and 100 pounds of eagerly-licking
horse, but not the 500 pounds of the front half of the pony, and in the
"breakaway" position it can't have any protrusions that may cut up a
(likely alarmed) equine.

Any suggestions?

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

Do you need to implement control loops in software?
"Applied Control Theory for Embedded Systems" was written for you.
See details at http://www.wescottdesign.com/actfes/actfes.html