Unicender 3-1 MA and other uses

JFornek18

New Member
So I recently picked up a unicender from Wesspur during the sale, and have started to find some unique ways to impliment it into my climbing. This first one is using it to set up a 3-1 mechanical advantage system for limbwalks. I have it paired with a rollclip z to limit friction. The other use is as a second lanyard adjuster for oddball uses.
 

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Winchman

Active Member
I can't see the entire rig, but I think what you have there is a 2:1 with a turning pulley. The Rollclip-Z doesn't add mechanical advantage. It just turns the line back toward you.

You can verify this by pulling one foot of line toward you. You'll move six inches toward your tie-in point if it's 2:1, and four inches if it's 3:1.

Be careful how you use the Rollclip-Z. It's fine for a turning pulley to make things easier, but it's not intended for life support functions.
 
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climbstihl

Well-Known Member
I can't see the entire rig, but I think what you have there is a 2:1 with a turning pulley. The Rollclip-Z doesn't add mechanical advantage. It just turns the line back toward you.

You can verify this by pulling one foot of line toward you. You'll move six inches toward your tie-in point if it's 2:1, and four inches if it's 3:1.

Be careful how you use the Rollclip-Z. It's fine for a turning pulley to make things easier, but it's not intended for life support functions.
No, it's a 3:1, because you are the one pulling on the end, making the upper pulley a moving one. It's the same system as RADS.
The Rollclip is intended for life support, the manual shows it being used on a bridge to connect your climbing system. It's only 20kN though, so maybe under your regulations you can't use it for life support.
 

Winchman

Active Member
The 2020 Sherrill Tree catalog page 79 has a caption in red capital letters under the pictures for three versions of Petzl Rollclips which reads:
"These are not for life support"

Their online catalog and Petzl's website descriptions don't show or say anything like that, though. Petzl's technical notice shows the Rollclip-Z being used to connect a Zigzag to the rope bridge on a harness. Can't get more like life support than that.

I have no idea where Sherrill's caption info came from. Probably something to do with regulations, like you suggested.
 

Batla

Active Member
The Rollclip-Z is rated 20KN - 8KN - 7KN and the WLL of the Pulley by itself is rated 4KN (2KN on each side). Petzl does not publish the breaking limit of the pulley, only its working limit. I looked at another pulley from Petzl. For a WLL of 5KN, their breaking limit is 15K which means a safety coeff of 3.
 

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Jonny

Well-Known Member
Different standards for Climbstihl in Germany I’ll bet. 20Kn is strong but I believe our magic number in the US is 22 or 23Kn. A DMM Revolver with Locksafe gate is suitable though, 24Kn and triple action gate mechanism.
 

Tuebor

Well-Known Member
Different standards for Climbstihl in Germany I’ll bet. 20Kn is strong but I believe our magic number in the US is 22 or 23Kn. A DMM Revolver with Locksafe gate is suitable though, 24Kn and triple action gate mechanism.
8.2.8 Carabiners used as part of a climber’s work-positioning (suspension) system shall be self-closing and self-double locking and shall have a gate-locking mechanism that requires at least two consecutive, deliberate actions to unlock. A carabiner shall be capable of withstanding a 5,000 pound (22.24 kN) load along its major axis with the gate closed without breaking or distortion sufficient to release the gate.
 

Tuebor

Well-Known Member
I can't see the entire rig, but I think what you have there is a 2:1 with a turning pulley. The Rollclip-Z doesn't add mechanical advantage. It just turns the line back toward you.

You can verify this by pulling one foot of line toward you. You'll move six inches toward your tie-in point if it's 2:1, and four inches if it's 3:1.

Be careful how you use the Rollclip-Z. It's fine for a turning pulley to make things easier, but it's not intended for life support functions.
Mechanical Advantage: 2:1 or 3:1?
 

JFornek18

New Member
Wow, this was very interesting to read. Thanks for all this insight, some real cool stuff. On the topic of the rollclip, as I understand it, in this system it is not life support, as if it were to fail, the hitch would hold me and I could snap on my Rope Wrench and go back to srt. I got it for some oddball projects that I am trying out, none of which are life support.
 

climbstihl

Well-Known Member
Different standards for Climbstihl in Germany I’ll bet. 20Kn is strong but I believe our magic number in the US is 22 or 23Kn. A DMM Revolver with Locksafe gate is suitable though, 24Kn and triple action gate mechanism.
Yeah, both EN 12275 and EN 362 require only 20kN.
 

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