Re: Need speed switch for DIY funicular/hillside elevator

["Robert L Bass" <robertbass1@xxxxxxxxxxx>]

<astutesolutions@xxxxxxxxxxxxx> wrote in message news:1162061065.466027.213040@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
> My dad and I built a homemade hill lift (in Europe refered to as
> funiculars) in Eastern Tennessee.  You can see a working demonstration
> and picture of it at:
>
> http://www.funimag.com/photoblog/index.php/20061026/a-do-it-yourself-funicular/
>
> The tram works fine, but I am trying to figure out some kind of simple
> safety mechanism in the event that the spools break loose from the
> gearbox or shaft and start rotating freely.  Since my wife and kids
> ride this thing, I'd like some kind of backup solution in the event of
> major catastrophe.  We are using 2 cables instead of one even though
> one can handle 5 times the max load, and we have a braking motor to
> stop, but both of those would be moot if the spool spins out of
> control.
>
> I am thinking of having some way of measuring the outfeed speed of the
> cable (or spool) and have some emergency brake apply if a limit is
> exceeded.
>
> Any suggestions?  I thought about putting fan blades at end shaft of
> the spool to have air slow it down, but that would be a little
> unsightly.  I'm looking for a simple solution, one preferably without a
> computer since this is outdoors and needs to be functional 100% of the
> time.  I'll take any flames in stride on this point.  I realize that
> this group is about computer automation, but its the only  one similar
> to this kind of project I could find :-)

A centrifugal brake should do the job.  Ideally, the brake engages as the drum starts spinning fast. As the brake slows the drum, it
eases up a bit, allowing a safe descent.  ISTR they used something like this on the tram at a ski lodge in NH.

--

Regards,
Robert L Bass

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