Need speed switch for DIY funicular/hillside elevator

astutesolutions · 2006-10-28T18:44:25+00:00

My dad and I built a homemade hill lift (in Europe refered to asfuniculars) in Eastern Tennessee. You can see a working demonstrationand picture of it at: tram works fine, but I am trying to figure out some kind of simplesafety mechanism in the event that the spools break loose from thegearbox or shaft and start rotating freely. Since my wife and kidsride this thing, I'd like some kind of backup solution in the event ofmajor catastrophe. We are using 2 cables instead of one even thoughone can handle 5 times the max load, and we have a braking motor tostop, but both of those would be moot if the spool spins out ofcontrol.I am thinking of having some way of measuring the outfeed speed of thecable (or spool) and have some emergency brake apply if a limit isexceeded.Any suggestions? I thought about putting fan blades at end shaft ofthe spool to have air slow it down, but that would be a littleunsightly. I'm looking for a simple solution, one preferably without acomputer since this is outdoors and needs to be functional 100% of thetime. I'll take any flames in stride on this point. I realize thatthis group is about computer automation, but its the only one similarto this kind of project I could find :-)Thanks in advance.Jeff

Oct 28, 2006 63 Replies

Rate this thread:

Jon Woellhaf 19 years ago

Yes, I mean the maximum speed during a runaway condition -- like if both cables failed.

I believe you said the vertical distance is 70 feet. That means the maximum speed the cart could reach is 46 mph, discounting rolling friction and air resistance -- if I remember my freshman physics correctly. Accounting for rolling friction and air resistance, I estimate the terminal speed would be no more than 40 mph.

That's probably too fast for my initial idea of a passive emergency deceleration system to work. I was thinking of a net across the bottom of the track held by bungee cords attached to posts or trees.

I think an engineer could design a water filled coaxial tube shock absorber that would safely decelerate a runaway cart. You'd have to add track beyond the normal lower platform. It looks like there's room.

A simpler solution is to add track all the way to the water with a level or slightly inclined runout portion and just let the runaway cart and occupants get launched into the lake.

Really cool device, by the way.

Jon

Vote

oldman1947.bs 10 years ago

I have read all the comments, on what they all have said and looked at your system. My system is very old, has only 1 cable. Very simple control for motor drive. Anyway back to yours. Like the daul cables, daul barrel pick- up. The cable size is over sized, great! And from what I can see the size o f the motor drive and the coupling used could pull a bus up hill without an y problem. As to the drum breaking and running freewheeling, i'd take it th e way it is and feel save. You need to take another look at the coupling, i f it's too small or you feel it's undersized, replace it, problem solved. If you still aren't sure, just remove it and walk up and down and send me y ou system, i'll be waiting.

Vote

oldman1947.bs 9 years ago

Hey guys found this company that sells overspeed safety lock brakes. ww w.china-Rigid.com, then search for overspeed unit. If you put a rope cabl e stationery from the top to the bottom, cable going thru the unit that is mounted to the underside of your people cart, would work. See what you t hink.

Vote

malcolmfifer 9 years ago

PLEASE Email me you Email address so I can discuss with Dad about supplying the motors etc. for the one I am planning. I am at snipped-for-privacy@gmail.com

Vote

Join the Discussion

Have something to add? Share your thoughts — no account required.

Didn't find your answer?

Ask the community — no account required