Re: Need speed switch for DIY funicular/hillside elevator

[nobody@xxxxxxxxxxxx (Dave Houston)]

I didn't say they were _all_ Goldbergian.

I spent about 20 years in the machine tool industry where safety was a prime
concern. It was always my philosophy that safety, like quality, is something
you design in from the beginning of the process rather than something you
paste on at the end of the process. Another thing I strongly believe is that
the possibility of catastrophic failure grows geometrically with design
complexity so - KISS. We had a machine that had to overcome gravity to
operate and I always figured that, should gravity fail, trial lawyers and
product liability suits would be the least of our concerns.

If a cable snaps, it's likely to decapitate an occupant (or occupants) of
the tram so a broken cable is unacceptable and having redundant cables is,
IMO, a serious design flaw. I think a single, adequately over-sized cable,
driven by a large diameter drum and inspected regularly (on a rigid
schedule) is better.

The drum then becomes the single failure point where you need protection
and, as I already stated, you will likely find winch manufacturers have
already dealt with preventing runaways.

astutesolutions@xxxxxxxxxxxxx wrote:

>I don't think that all the suggestions are necessarily goldbergian.
>There are 2 possibilities, stop it at the head unit (at drums) or stop
>it at the cart.  Each offers its challenges, but not impossible.  Its
>just a balance between what I can actually build, and what will take
>the least amount of maintenance.


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