At 08:49 AM 1/2/2006, K7LXC@aol.com wrote:
>Howdy, TowerTalkians --
> Here's an interesting automatic tower on a trailer - just push a button
>and it extends to 80 feet! There's a video that peeks into the inner
>- it's a fascinating engineering job. I don't think anyone wants to know the
>price - hi!
The mechanics on this are very clever with the three ladders that lock
together and extend. There's a smaller scale scheme used for extending
masts on spacecraft that looks like two measuring tapes (with the curved
cross section) face to face that interlock as they extend.
There's also a couple of nifty schemes that essentially "unscrew". The
mast made by AEC-Able on the Shuttle Radar Topographic Mission (SRTM) works
this way, and there are ground based equivalents.
There are really interesting extendable tensegrity towers too.
There's a lot of nifty ideas out there.
We've talked a bit at the JPL and CIT clubs about putting hydraulics or
lead screws on the outriggers on the tower trailer (since that's one of the
more time consuming parts of erecting the tower), and it probably wouldn't
be all that expensive, if you have someone who can do the welding and steel
fabrication for you. 4 ag hydraulic cylinders would probably work just
fine. A suitable valve block and a pump, etc.
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