hitch doesn't fit

I had a couple of latches on trailers give me some trouble over the weekend. A pickup box trailer would not latch for nothing,even with the hammering. We chained it down and moved the trailer (around to the other side of shop). I took the latch apart, made a minor adjustment, reassembled it and it works fine now. The 35' travel trailer (1952 heavy beast) had the latch "frozen" but it dropped on ok, just would not latch. Plenty of tongue weight, so went slow and moved it from behind shop to other side of front yard.. liberally sprayed the latch with PB Blaster and will make sure it works for next time. I would never knowing tow anything off our property without a properly working coupler.