Bunk

From Bytesmiths

When it became clear that Veggie Van Gogh was not happy pulling even a small travel trailer, I began thinking. (Dangerous, that!)

The inside was filled with shelving. Kitchen space was available on the shelves. A porta-potty could be stored under the shelves. But where could a bed go?

On our first post-trailer trip, we put an inflatable mattress on the floor. What a disaster! You couldn't get from front to back safely, and worst of all, i couldn't stay in bed while Carol cooked breakfast!

Bunk in raised position.

After mulling over numerous designs that involved swinging pivots, motors, hydraulics, and even cutting away large body sections, I did what I normally do when I can't find a simple solution to an engineering problem: I wandered around in hardware stores.

It was in a Home Depot where I spotted the barn door track. This normally mounts horizontally, and has a "U" cross-section with the tips of the "U" curled in. Wheeled trucks then ride in the track and support the considerable weight of a door large enough to allow tractors to get through.

Over in the next aisle, I spotted some solid brass wheels for large, heavy sliding glass doors, and the plan began to come together. If I quartered the barn door track and mounted the four sections vertically, rather than the way God intended, the bed could go up and down. And if I attached wire cable to the wheeled trucks, and ran it over pulleys to winches, the whole thing could be easily raised and lowered. And I had one week until the next show!

Bunk bottom in raised position.

I used 2.5 cm (1") angle iron for the frame, and expanded steel for the base, which I painted with aluminum paint. A sheet of corrugated plastic went on top of the expanded steel, and six inches of firm polyurethane foam on top of that. Double-bed sheets fit perfectly!

This was the first time I had welded expanded steel, and I learned a valuable lesson: it expands even more when it gets hot! I had welded every diamond corner, and the excess heat made the base sag. (Later, I looked at someone else's welded expanded steel, and they welded only every fourth diamond. Live and learn.)

But Carol didn't want to keep rolling into me all night, and came up with an elegant solution. She made a flat fabric bag the size of the bunk platform, and put a bunch of styrofoam packing "peanuts" in it. She smoothed them out to a flat surface, and we put the matress on top.

Crank for raising/lowering bunk.

The numbers were a bit of a nightmare to figure out, and I must have measured things dozens of times and filled the backs of many envelopes with undecipherable chicken-scratches. I had to build it to within 1.5mm (1/16") tolerance for the wheels to ride in the tracks properly. Amazingly, the truck body was square within that tolerance!

There were extremely limited mounting options. Although the rear jacks could go anywhere, the only place the front jack could go with any reasonable support was right next to the door. This meant there would be a gap in front, so I built a shelf so that we wouldn't be dropping things off the bed in the night, and also to give us a place for glasses, eye-drops, alarm clock, and other stuff that would be more at home on a night table beside a bed.

Pulleys supporting bunk cable.

The whole think goes up and down with the help of two boat winches. I welded a piece of angle on the base of the winch for mounting the winch to the body.

From the winch, steel cable goes up over a pulley, then down to the wheeled truck attached to the bed frame.

On the rear jack (pictured), a second cable goes over a second pulley, then up to the front jack.

One of the nicer things about this design is the adjustability: all the way up for loading and unloading, all the way down for sleeping. But in the down position, it was impossible to drive without scrunching down in the seat, so I came up with a third useful position, which we call the "driving position".

Bunk in driving position.

When in this intermediate position, the driver can sit upright with plenty of head room, and a passenger who is not excessively claustrophobic can slip into bed and take a nap!

This proved to be quite useful on longer trips, and we became good at "round the clock" driving, which is difficult to do if the passenger is trying to sleep sitting up.

Having the weight of a grown adult above me while I was driving, supported by cables, was a little spooky. I drilled holes through the jacks and put clevis pins through them while driving. We then lower the bed onto the pins, which avoids having all the weight on the cables, and also provides additional safety for the driver. I don't want a broken neck because of a broken cable!

A level aids winch adjustment.

At first, I came up with lots of hare-brained schemes for running pulleys and cables all over the place to try to make this thing go up and down with a single winch. But the more I thought about it, the more I realized that two winches were a feature, not a bug!

I glued a bubble level on the back of the frame where it is in easy sight from either winch. When we stop for the night, we crank the bed all the way down, then raise one end or the other until it is level.

Bunk in lowest position.

Other than banging our head on the fool thing until we instinctively learned to duck when going back and forth in the truck, the bunk did a great job, until we got to Southern Utah in August.

It was so hot! Chorus: "How hot was it?" It was so hot that one could get second degree burns from touching the inside of the truck body!

So Carol set to work insulating the bunk area. She cut leftover pink foam insulation from installing the vegoil tanks into pieces that fit in the nooks and crannies of the body, then covered them with aluminum-backed firewall insulation.

Now it's much more comfy, and we feel like we're sleeping is some cozy space capsule cocoon!

I've run out of words, but not out of pictures. If you aren't totally bored by now, here are a few more images, linked to larger ones.