Re: Need speed switch for DIY funicular/hillside elevator

[Nick Hull <nhull@xxxxxxx>]

In article <1162146319.261265.119310@xxxxxxxxxxxxxxxxxxxxxxxxxxxx>,
 astutesolutions@xxxxxxxxxxxxx wrote:

> Frank Olson wrote:
>
> >
> > What you really need is a "third rail".  You could then install a set of
> > brake calipers on the cart to act as an emergency stop.
>
> Yes, this is sort of what we were talking about with a fixed center
> cable.  The trick is how to get the brake caliper to determine when to
> grab
>

Elevators often have a brake that is held off by the cable tension where
it attaches to the cab.  you can do the same thing, the cable attachment
holds open a brake that would grab the rails.  If the cable breaks or
loses all tension the brakes grab.  Even if the cable slacks, there
should still be tension at the cart attachment point.  This is totally
automatic, no user input.

--
Free men own guns - www.geocities/CapitolHill/5357/