Had a 98% great trip to Pawnee National Grasslands, but the wiffletree raising mechanism froze when we were putting it up. There was a strong side wind as you get in those areas, and the resulting pressure on the sides of the top when raising made the screw sort of cross thread and seize breaking the shear pins (and no longer run smooth). It got close enough to up when I stopped it and I got the door on and it was a great camping trip. But trying to get it down, it didn't go and actually spun the wires on the wiffletree and became quite a mess before shearing the pins off to stick open. One of the advantages of building the damn thing was I was able to get it down by taking all the cables off and lowering it with help of my wife. Got home safe and sound.
So I decided to redesign how I would make this darn thing raise. Looking at the cables, it appears that it pulls the cables approximately 17" to raise the top 51"--so it must go through a 3:1 mechansim in the arms. The top, knowing that I can put some crap on top of in the future can weight what? Say 300lbs. max. But you get friction too, so say 400lbs. You have a 3:1, so I need something that can lift 1200lbs 17" minimum. Fine. I decided on this beast:
https://www.progressiveautomations.com/heavy-duty-linear-actuator PA-17 model with an 18" throw and 2000lb load and wet location, IP65 with a stainless steel body. It has built in adjustable limit switches too and is pretty darn quiet. It is huge but fits across the width of the trailer (by 2" open!).
I have ripped out all the other mechanisms and am currently working on the mounts. It will mount to the trailer frame in back and then use a unistrut trolley wheel system on the sides for it's travel on the front. I have to make a U bracket which I am bending out of 1/4" steel in order to move the cable holder back to it's original position. Here is the basic layout along with the underside of the trailer with existing cable locations before I cut out all the cross members. The Green and Yellow donuts in the sketches are the pulleys that will be welded onto the unistrut braces. I am going to make the assembly as a tray that I will weld in as one piece. More on this as I start welding things up!