Simple 3:1 technique

Reg

Well-Known Member
Here’s a relatively cheap and simple means to pretension a line through a basic lowering device.
A couple of pauses in the vid where I momentarily forgot where the whole thing was headed, but the video has come out quite clear so its easy enough to see what’s going on.
The video is also a response to Toms question right at the end of this thread:
http://www.treebuzz.com/forum/showflat.php?Cat=0&Number=198476&Main=161156#Post198476

http://www.youtube.com/watch?v=TMADD6KV0ZY

Thanks
 

chris_girard

Well-Known Member
Hey Reg, thanks for posting the video. Did you engineer the RC31 Rope Pulley for Stein when you developted the lowering device?

It seems like a nice quick way to generate a 3:1 MA. Very clever rigging aid that seems much easier than using a regular rigging pulley. Thanks for sharing, and where can we get one here in the States?

I also noticed the Stein helmet that you have on. Has that replaced the blue Stein helmet that you had before?
 

Reg

Well-Known Member
[ QUOTE ]
Hey Reg, thanks for posting the video. Did you engineer the RC31 Rope Pulley for Stein when you developted the lowering device?

It seems like a nice quick way to generate a 3:1 MA. Very clever rigging aid that seems much easier than using a regular rigging pulley. Thanks for sharing, and where can we get one here in the States?

I also noticed the Stein helmet that you have on. Has that replaced the blue Stein helmet that you had before?

[/ QUOTE ]

Thanks Chris. I first put together a rough one with the LD in mind to see how well it worked, thereafter we approached/asked ISC to engineer the more refined version used in the vid.

Hopefully they'll be readily available over your way pretty soon. The first batch is being produced right now.

One thing I should have mentioned is that while the technique works very well on the device in the vid, and certainly on any fixed LD, I haven't tried it on the regular portawrap....might work great, might not work at all!

The helmet is just a basic one for groundwork, available in abundance. Thanks again
 

chris_girard

Well-Known Member
[ QUOTE ]
One thing I should have mentioned is that while the technique works very well on the device in the vid, and certainly on any fixed LD, I haven't tried it on the regular portawrap....might work great, might not work at all!

[/ QUOTE ]

Reg, you read my mind. I have a GRCS and large Portawrap and I was wondering how it would work on the Porty too compared to the LD in the video.

I'll just have to get one and find out.
 

chris_girard

Well-Known Member
Reg is like Gerry Beranek, Greg Good, Ken Johnson and Don Blair and Ed Hobbs.

True inventors that are more interested in the functionality of a design versus shear profit that can be made. They are people that are out there in the trenches with the rest of us.

I for one salute their creativity and look forward to using their products as often as possible.

Thanks Guys!
 

Axman

New Member
I give it a definate thumbs up. I like it. Much more steamlined in terms of gear and set-up to use when the need comes up.

You did your home work on this one.

Hey Reg , try smiling a little. If the grin icon doesn't show -up I am just poking a little fun at you , nothing personal.

I have always been impressed with your work.

Larry
 

Reg

Well-Known Member
[ QUOTE ]

Hey Reg , try smiling a little. If the grin icon doesn't show -up I am just poking a little fun at you , nothing personal.

Larry

[/ QUOTE ]

Talking to a camera as if its an audience is a ridiculous feeling Larry, for me at least. I find it difficult to smile under such circumstances. Thanks though, glad you enjoyed watching.
 

Paul Biester

Active Member
My favorite thing is being able to hang the block like you did! Cool little welded piece of round stock,slide right through the eye splices nice and smooth!
 

Daniel

Well-Known Member
I AM subscribed to your youtube channel, so I got a look at the vid as soon as you posted it... That's a great idea and a big step forward in your presentation..

Good thinking... idiot proof technique...

What do you think of bypassing the pulley, and just going with an open screw link, permanently tied to a loop of something a bit thinner? It would be smaller, lighter, cheaper, and easier to set up... the added friction would be negligble... Most of us wouldn't even need to make a trip to the store to set that up...
 

Reg

Well-Known Member
thanks all

[ QUOTE ]

What do you think of bypassing the pulley, and just going with an open screw link, permanently tied to a loop of something a bit thinner? It would be smaller, lighter, cheaper, and easier to set up... the added friction would be negligble... Most of us wouldn't even need to make a trip to the store to set that up...

[/ QUOTE ]

Dan, yeah it works, just knowhere near as well....although of course I would say that in trying to promote the pulley!

Seriously though, the wraps on the LD already slow things down a little, so by adding more friction at the top via a tight radius might render the M.A hardly worth it.....especially if you're actually lifting and not just tensioning etc. Thanks for subscribing, guess I'll have to talk some more.
 

Daniel

Well-Known Member
Ya I was thinking about that today... I mostly consider that a tool for pre-tensioning, not so much lifting, as a better system with mutiple pulleys would be recommended for lifting. I have a GRCS that gets very little use, so we are mostly able to work with gravity (or just bring in a crane for the big ones that need to go up)... Though I often like to have the line pretensioned..

That said, I was thinking of the friction on the porty as an issue, which can depend on the porty itself.. So to get around that, how about using an independent line, something short and terminated to a biner or snap, to quickly clip on and off the porty? That should eliminate a good bit of friction on the porty, and make up for the added friction on the screw link...
 

DSMc

Well-Known Member
Reg, great presentation. Of the three lowering devices you have designed, this small one is my personal favorite. The simplicity of design and its apparent ruggedness and useability appear to be perfectly balanced.

Your technique on simplifying tensioning with your pulley is super. Again, simple and efficient.

Tools and techniques can always be tweaked beyond their original design. Personally, I would not change a thing on these two items for the applications intended.

Dave
 

Jman

Well-Known Member
Nice Idea. Maybe one step further get a longer sling and wrap it around the trunk of the tree and then put that pulley on it.

It'll still tension the line and you don't have to take it on and off all the time.

Might not work in the real work just inside my head. It might not sit at the proper angel...worth a try.
 

Reg

Well-Known Member
[ QUOTE ]
Ya I was thinking about that today... I mostly consider that a tool for pre-tensioning, not so much lifting, as a better system with mutiple pulleys would be recommended for lifting. I have a GRCS that gets very little use, so we are mostly able to work with gravity (or just bring in a crane for the big ones that need to go up)... Though I often like to have the line pretensioned..

That said, I was thinking of the friction on the porty as an issue, which can depend on the porty itself.. So to get around that, how about using an independent line, something short and terminated to a biner or snap, to quickly clip on and off the porty? But that should eliminate a good bit of friction on the porty, and make up for the added friction on the screw link...

[/ QUOTE ]

Dan if you mean clip the extra line to the top of the porty then up through the pulley and back down, then you’re reducing ratio to a 2:1, unless I’ve misunderstood….any more legs and its becoming like a fiddle-block set up. Consider also that when you start using additional lines you then have to tend the slack of the lowering line, unlike the set-up in the video. Of course there are any number similar such methods of gaining a MA, this is just one that I designed a pulley for.

I’m surprised you don’t use you GRCS more Dan? I was lucky enough to work with a company who had one a while back and it always performed splendidly.

Thanks Dave & Jman.
 

Daniel

Well-Known Member
It would be nice to get a dyno and check the forces involved in the diffferent scenarios.. You are of course correct about the 2:1 vs 3:1.. I AM just wondering how much of that 3:1 gets lost with friction on the porty... I love thinking about this kind of thing.. Maybe one day, I'll get a dyno and start taking notes... thanks for getting the wheels turning... (no pun intended)
 
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