Instructables

Zip Line Claw Help

I am attempting to make a claw/clamp like device that could hold an object and then ride along a zip line. I have most of the details figured out but I am stuck on what I could use for the claw. It would have to be able to hold about 10 lbs and then have a pin release. I would prefer off an off the shelf item but could do minor modifications. Any ideas?

Thanks

I haven't any ideas for a clamp. But what about putting the 10 LB load
in a wooden box which has a hinged bottom? The opposite side
of the hinge would then be where the pin goes.
You could also try a two door hinged bottom with the pin located in the middle
where the two doors meet.
madigajm (author)  RavensCraft1 year ago
While that is an interesting and good idea, for this project the loads will widely vary in size, so I don't think that would work very well. The box would have to be so large it would weigh more than the load. Thanks though!
Orngrimm1 year ago
Well... No word about cost? If cost is no problem, just buy a normal zip line trolley for around 100-120$:
http://adventureropegear.com/cart/index.php?cPath=49_54

If you want go cheaper and dont need rolls you could go for something like a clevis (http://www.oreillyauto.com/site/c/search/Clevis+Pins/N1760/C0142.oap) but that will damage the zipline over (short) time.

Some good ideas can be brought up by looking at existing patents.
As an example:
"zip line trolley" in google patent search gibes stuff like
http://www.google.de/patents/US20110239898
where you see in the figures a detailed plan of every part...
Also the quick-release is visible and may spark some ideas.


I for my part (if i would bild such a thing) would try to make it in one of the following fashions:
- Make a "kicker" where the trolley slides off the side (lift it first with a ramp on the cable) of the cable
- Let the cable "end" in a non-stop: take the cable over a wheel and fix the cable maybe 90° to the ground. If the non-closed (!!) trolley arrives, its forward-momentum will let it ride over the wheel and bent cable thus off the cable.

Both ideas above are only usable if the freight is durable and doesnt break since the stop is nothing short of a crashlanding.

If i would go with a DIY-way, it would look like:
http://picload.org/image/agiproc/untitled.png (i painted that just for you).
The thing is seen from the front and would sport 2 rollers in a line (added stability).
The rolls can be off-the-shelf and the 2 plates (red) can be made/cut from normal steel or even aluminum or whtever you have at hand...
The pin can be of whatever design you find fit.
madigajm (author)  Orngrimm1 year ago
Thanks, I appreciate the response but let me clarify a few things. The actual zip line function is not what I need help with. What I need help with is something that can clamp/claw onto lets say a box, and then release it when a pin is pulled. Got any ideas?
Ah! Sorry... Misunderstood you there in this case... English is a foreign language to me, you know... :)

So you are looking for a quickrelease clamping TO the trolley then.

One 100% off-the-shelf-idea:
Buy a compound-release (Archery)!
See, a compound gets pulled (normally) with a release which can pull over 60 lbs.
If i were you, i would go for a hand-wrist-one. Not a hand-one.
See http://www.bowstuff.co.za/media/catalog/product/cache/3/image/800x600/f0a4495386af0d0c4a8ef36df3e80c54/c/o/cobra-all-adjust-2.jpg

They go online (used) für around 20$ like here:
http://chillicothe-oh.americanlisted.com/sport/compound-bow-release-20-leesburg_20809155.html

Best is if you check for a simple way of attaching the release to the freight. And the pictured cobra-release is quite handy in those termn: They have this flat-nyon-band-fixature (no idea whats the name in english) like on a backpack...

Now all you have to do is:
String a loop on your trollex and attach the load to the release.
Then attach the release to the string and let it go. :)