Here's the refined traveling crane version

[Ron]

Here\'s the refined traveling crane version

You may recall that when I set up the demo of the traveling crane, I realized the Tandem Speed had a rubbing problem due to the slant of the 'crane' line. So, I redesigned the 'traveling' part and here are two versions, one with inexpensive, but inefficient SMC pulleys and a second more expensive, but more efficient, with two Petzl Minis and a HitchClimber pulley. If I had a third Mini, I'd have used it instead of the HitchClimber, but again a case of use what you have. The Minis are ball bearing pulleys, spec'd at 95% efficiency. The HitchClimber is also, hmmm, wait a minute, I just looked at the manufacturer's data sheet and it doesn't specify bearings or efficiency. I may have to redo the 'high efficiency' version. Anyway enjoy ther pretty pics.

The low efficiency version:

and,

The high efficiency version (or what I thought was):

and,

In this setup, pulley efficiency is important because when the load travels along the speedline, three pulleys are involved and to raise the load via the 'crane' line, two pulleys are involved. BTW the crane line is on a theoretical 2:1 so theoretically, i.e. with 100% efficient pulleys, a 50 lb pull on the 'crane' line would raise a 100 lb load.

 

[RogerM]

Re: Here\'s the refined traveling crane version

very cool to see it in color.....Dr. David Merchant has a very cool book that illustrates many of the same concepts your talking about....."Life On A Line" The Underground Rope Rescue Manual....second edition. Thanks for posting.

 

[Ron]

Re: Here\'s the refined traveling crane version

[ QUOTE ]
very cool to see it in color.....Dr. David Merchant has a very cool book that illustrates many of the same concepts your talking about....."Life On A Line" The Underground Rope Rescue Manual....second edition. Thanks for posting.

[/ QUOTE ]
Thanks Roger and thanks for the heads up on the book. I can do a web search for the book, but do you know where I can buy it?

Thanks,
Ron

 

[RogerM]

Re: Here\'s the refined traveling crane version

I went to my local "big book store" I think ours is "Border's" They special ordered it for me. Just to give credit where credit is due....Tom D gave the heads up on the book a while ago. It has been a great reference and the math, well lets just say (to quote the book) math is icky! Worth every penny.

 

[Ron]

Re: Here\'s the refined traveling crane version

Roger,

Thanks again; I'll get a copy - sounds like a very interesting book!

 

[easyphloem]

Re: Here\'s the refined traveling crane version

I think I might try a modified version of this to hang a squirrel proof birdfeeder in my front yard.

So far, the squirrels have gotten the upper hand on me.


SZ

 

[Colin]

Re: Here\'s the refined traveling crane version

use 45lbs test fishing line

 

[Ron]

Re: Here\'s the refined traveling crane version

[ QUOTE ]
I think I might try a modified version of this to hang a squirrel proof birdfeeder in my front yard.

So far, the squirrels have gotten the upper hand on me.


SZ

[/ QUOTE ]
What an interesting application! I know squirrels are difficult to keep out of birdfeeders.

I remember watching a demo video at ACE Hardware of a birdfeeder that starts spinning when a squirrel gets on it. They showed some actual examples and I stood there chuckling and must have watched the thing three or four times.

Jeff's idea about the 45 lb test fishing line sounds pretty good too.