Sunday, November 16, 2008

The Long-Lost Tilt-O-Rama Construction Details!

In a previous post I promised to find some more of the construction details of the "Tilt-O-Rama" rework. After scouring some old computer drives, I finally came across the rascals:

Prototyping the "Crow's Nest": The design of what we were delivered was a clunky device that would only accommodate the most average of passengers. If I was to improve upon it, I needed to make sure that it would fit most (if not every) person that approached it. I did not want to see another show where the presenter was a lousy judge of height or girth and had to send the volunteer back to the audience when they didn't fit.

To be fair- being a huckster is a high pressure business, and mistakes can easily be made in the heat of the moment. It is not really the presenter's fault, but that of poor design.

To facilitate the design process, I devised a prototype "nest" whose configuration could easily be adjusted. It was a dog's breakfast of clamps, unistrut, MDF, and a sawhorse - but it allowed me to take our largest and smallest employees and perform a "fitting."

After I was satisfied that the contraption would safely hold the entire human bell curve, I used the prototype as a template to render the final product in steel. The slanting hand-holds provided a comfortable grip-distance for large and small, while the "bail" would entirely encompass the passenger such that they could not fall forward. Unlike the original, the participant could now "throw their weight around" as there was great freedom of movement of the person's center of mass.

The "bail" could be quickly closed and secured by employing a device constructed from coil threaded rod and a giant wing-nut. This is used in make molds for contrete, as the threads are not easily fouled because of their loose tolerances. To make the latch, I made a length-wise split slightly past the center of the rod's axis. This allows the wing-nut to travel the entire length of the rod without binding - even if the bail is not closed. Powder coating had no effect on the operation of the threads.

To use, the presenter closes both halves of the bail (the small pin in the center provides registration - a bit of over-kill there) and gives a wing of the nut a sharp smack. The nut spins easily down the halves securely joining them. The wing-nut is trapped by a steel disc on the end of the rod - there is nothing to lose.

Here is a better detail of the ankle-cuff system before it was placed on the "Tilt-O-Rama." You can now see how the Suspa cylinder advances the racks to simultaneously rotate the cuffs. The Suspa system is normally used for raising and lowering workbenches and depends on the weight of the bench for the system to be lowered. Since gravity was not helping me here, I had to place a pair of large constant-force springs on each of the cylinders to give them the needed assist when cranking them back open. Somewhere I am hoping to find some grainy video I took with my Palm of the mechanism in action.

My Museum Clan

Our museum's director took another position this Fall, and the staff put together a web-published book for her as a parting gift. I had my department stage this photo in front of our cave exhibit as our contribution to the project. Yours truly on the left. The Education department kindly loaned us the skins.

The guy standing in the middle is our cabinetmaker. His image looks a little off as he had to be photo shopped in afterward. He was insistent on getting a haircut before the shoot (apparently unclear on the concept of "look like cavemen") and didn't make it back in time. The shoot had to happen before the public came at 10 am and he didn't make it back.

All in all we think it turned out OK.