Bulldog makes the best coupling on the market imo, a pintle works good too but they can slam a bit. The bulldog ones will bite your fingers so be careful, and if they get hung up just kick it closed. I've got one on the chipper, and have had them on random work trailers over the years, i love them, simple, heavy, and they just work.
Speaking of biting fingers i did something stupid and somehow bounced a baby saw on the back/ side of my hand (one handling a baby battery saw while holding, dicing up some small limbs for the wood pile, yes I'm an idiot). Cut clean, through the leather glove obviously, probably could use a few stitches since it was deep enough, but i think I'm ok. Washed it out really good with running water, then peroxide, then the antibiotic cream, and a big bandaid, which of course needed some electrical tape to hold it in place better cause i am going to be taking gloves on and off all day at work tomorrow.
Everything works good so no ligament or tendon, no heavy bleeding at all so didn't cut any pipes, didn't even really hurt much either and i got feeling everywhere so no computer wires. I'll rock the bandage and reasses tomorrow to see if i need to go in, after a day or two with no problems I'll probably glue it so it can finish healing if it's not there already. First kiss with a chainsaw, and i fully plan on it being my last, more annoying than anything else cause i don't have time for this bullshit right now, not to mention it's a red badge of dumbness to do stupid things and predictably bleed as a result. At least it was in a fatty spot and was my smallest saw i own, and was almost stopped when it happened, could have been much much worse.