I'm sure we are all using the same wiring schmatics so a patent would be a difficult thing to certify - but maybe?????
Anyway, simular idea as above but my case was a cheapo piece of pvc drain pipe and two flat glue caps (not glued for this project). Total costs about $20. I also used a 3-way toggle switch for cost savings. All through connections were water proof and the end caps fit snug for the same reason but not glued for access.
I generally leave this unit on my pigtail at home. Keeps the contacts clean and dry. Also helps as a one person light check several times a year without hooking up the TV. Very handy and very easy to make.