I have a camp bed that's a folding/expanding support for a queen size air mattress. (I don't have a photo of my actual bed, but it's very much like this one.) I love this bed. It's comfy, easy to set up and break down, compact for transport, etc.
The problem is, with all those tiny feet, it's tricky to shim the bed level. Any one foot is likely to slip off a levelling wedge, without something larger underneath it for the foot to grip. In addition, levelling each foot is impractical, but levelling only certain feet (such as the outside corners) would put undue strain on the joints between the leg sections.
For many years I was lucky, and got relatively flat camping spots. But in 2007, at Pennsic 36, when the group I camp with moved to our new land block, it became clear that I needed to find a levelling solution. (Nearly every morning I woke to find my sheets had come untucked in the night, and I had ridden them and all my other covers downhill to the end of my bed.)
So over Independence Day Weekend in 2008, my Dad and I got together to construct the solution. Dad and I had the same basic idea for a support for the bed frame. The idea was to create something upon which all twelve bed feet would rest, avoiding strain on the bed frame. Then the support could be shimmed up at the ends, and it would bear any strain of being suspended between the shims.
I should mention that while I'm including this project on my portfolio page, it was really more Dad's project than mine. He came up with the final design, he did all the cutting and drilling. I helped out by fetching tools, supporting lumber as it was cut and drilled, and doing minor assembly and measurement/math checking.
|The final design was basically three lengths of two-by-four, which support all twelve bed feet. Those support lengths are held at the proper spacing by two cross-braces, bolted at all six intersections.
We originally thought we'd add some sort of brackets to the outer four corners, to hold the bed feet in place and keep them from slipping. But then we decided that since the two-by-fours are a good 3/8" wider than the bed feet on each side, that should give them plenty of surface area upon which to gain traction. As the whole point of this project was to make the bed support level, there was no real reason the bed should be inclined to slip off the supports. So we decided to omit the brackets as they would just add bulk, weight, and would be easy to damage by knocking them into something in transport.
After completing construction I applied several coats of polyurethane to the pieces to help protect them from the elements while in transport on the roof of my car (and also from any puddles that might form under them while in use).
|At each intersection, a bolt was passed through a washer, the upper cross-brace, the lower support, and into a t-nut (shown in the middle at left) embedded into the underside of the support.
I should mention that embedding the t-nuts was a very finicky process, involving the use of drill bits graduated in very small increments to achieve the correct fit. If you want to create a similar support and don't have such a set of drill bits, it would probably be safer to use carriage bolts and regular nuts, with the domed head of the carriage bolts placed on the bottom of the supports (so as to keep any sharp hardware edges from tearing holes in your tent floor.)
|As I went to assemble the support at Pennsic I ran into a delay as I discovered I had been sloppy with the polyurethane and let it get inside the t-nuts. (In hindsight, yeah, that was stupid. But cut me some slack. It was my first time working with polyurethane.) Thankfully though, the dried bits of polyurethane were relatively easy to dig out of the threads.
Once assembled and with the bed atop the support, I discovered a slight flaw with Dad's and my logic. When left alone, yes, the bed stayed in place just fine. But just in arranging the covers I discovered I kept knocking the bed off the support, and I didn't want to discover what would happen if I tossed and turned in my sleep without securing it. So I tied the bed to the support with several lengths of para-cord. Even with this discovery/realization, I'm glad we didn't build brackets into the support. They really would have been too easy to damage, and unnecessarily bulky.
Once that adjustment was made the support worked perfectly. As you can see in the photo that's a good thing, as my bed wound up on a very sharp incline at the beginning of a ditch.