This is almost exactly what I've been looking for. I've seen this pic before but didn't know that it had a name. Rope and a friction hitch and that thing will cam like no other and be quiet. I've seen version's of it on here before, basically LW's essentially cut down to platform size.. What keeps the brace from potentially dropping out the bottom?
On mine, I run a short piece of Amsteel whoopee sling from the bottom of the platform to the support rod. It works well but honestly, I've hunted off of these for 30 years or more and I never used to do anything to keep it from trap-dooring. Heck, in those early days, we weren't even wearing harnesses. Obviously that was in the old days and times have certainly changed in regards to safety.
As well as the whoopee sling works to eliminate trap door, I think an even better solution would be to run a 2nd strap around the tree to hold the support post in place. The reason I say that's better is that it will tolerate side pressure better. Yeah, the whoopee will stop trap door but it may not stop the support rod from losing it's "seating" where it meets the tree when extreme side pressure is exerted.
There's another reason a 2nd strap would be better.
We all know trees aren't perfect. They lean, they bend, they have knots, bumps and all sorts of imperfections that can complicate setting a stand.
If these Andy stands have a weak spot, it's when they are hung on the side of a leaning tree. You obviously want the stand set level (side to side) but if the tree is leaning then the post won't meet the crown of the circumference...it kinda makes contact off center. That is a situation where I can see a issue with the post having some sort of slippage or failure. I struggled with those kinds of trees many times. Hey, even with conventional hang ons or predator type stands, those can't be leveled very well on a side lean.
But with the Andy and a 2nd strap, that post can be securely positioned tight very close to the crown of a side leaning tree (within reason).
A piece of Amsteel daisy chain and a truckers hitch is quick to rig and it would prevent that post from ever failing on you. 2nd strap beats the whoopee but the whoopee is better than nothing. And I guess you can get fancy and employ the 2nd strap in conjunction with the anti trap door cord. Could probably use the same length of amsteel. Just run the tag end up to the platform after you've made the 2nd strap and truckers hitch.
I think doing both may be overkill but safety 1st.
Just remember to always be tethered before you step onto any platform. And I firmly believe a tether beats the lineman hands down on that part of your set up.
Linemans can be a brutal ride down the side of the tree. They don't alway prevent a fall they just slow it down while a rough barked tree skins you like a cheese grater.