During a storm, a gigantic maple tree came down in our emu enclosure. Luckily it didn't land on the fencing or any animals, but getting in and out with the truck to clean it up has been a hassle. To open the badly-sagging gate, get the truck inside, prevent the emus from running through the gate, and get the gate closed requires both my wife and I. It will be even worse when I've finished bucking the tree and have to tow the log splitter and the wood chipper through the gate, because it will take longer to get those items through.
What I'd love is something like this, to at least automate the gate part:
That's the OzAutogate, a brilliant invention from Australia. You don't have to get out of the truck, you don't have to worry about a power source like with an electric gate, it automatically closes behind you, and the design is not liable to sagging.
It also features a dampening closing mechanism, which you can see in the demo below. You can also see the one feature that definitely needs some design attention, the little bar you use to lock it in the open position:
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Sadly, this wouldn't actually work in the emu pen—they'd run right into that ramp and trip over it (you cannot believe how dumb an emu is). But I think the design is brilliant for other applications.