Zigzag: Maintenance failure leads to accident

Winchman

Active Member
I think the labeling in the pictures is misleading. I just looked at my ZZ, and the only part with a spring is the release lever at the upper end. There's a similar piece on the next link down that moves, but it doesn't have a spring. All the other parts that come in contact with the rope appear to be fixed rigidly to the rivets that hold the chain together.

Mine has SN 19F019... It was purchased new in 2019. The one in the report has SN 18d013...

I can't wait to see the full explanation from Petzl.
 
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surveyor

Well-Known Member
Perhaps Petzl should consider a small set screw to adjust tension on the top link. That is how my pulley/rack design worked to use the rope itself as the "spring" in the device, by creating a slight bend in the rope.
 

CutHighnLetFly

Well-Known Member
I have no idea. But you can't have a spring failure on a part that never had a spring. Smells pretty damn fishy, to me.
Looks like an older model in the picture I saw on Facebook. I mean I dunno what the lifespan is on those, I've never owned one, but it looked like a well uses zig zag, someone correct me if I'm wrong here
 

JeffGu

Well-Known Member
That's a slightly used Version 3 unit with no obvious wear on it, a little dirty, and nothing missing or broken. Two different parts of the device circled, with arrows, neither of which have any springs or operate as described in the article. There is ONE spring in a ZigZag, on the top release lever (which is clearly working fine in the photo). There is a similar lever plate mounted on the pin just below the release lever, which faces the opposite direction and which has no spring. It is the combination of these two parts interacting with the rope that allows descent. Very much like pushing down on the top couple of coils of a friction hitch releases some of the friction. The cam/link pins shown in the second picture (the bottom four link pins) have grooves that always face toward the rope. They are fixed to one set of sideplates, and rotate on the other set of sideplates. This is true of all of them. They are solid stainless steel, are not hollow, and have no springs. Their orientation can't rotate very far because of the way the links fold up when installed on a rope. Even if they could somehow rotate, it wouldn't drop you, the device would have far too much friction and would come to a stop on the rope.

The article's second pic is not a good pic. I'll post a better one, where you can see the second release lever. In the article's pic, it's folded back against the second link and you can barely make it out. That second lever has no spring and is supposed to just flop around as described in the article. Clearly, they don't have any idea how a ZigZag works or are just trolling.

100_2832.JPG
 
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Tony

Well-Known Member
I think the labeling in the pictures is misleading. I just looked at my ZZ, and the only part with a spring is the release lever at the upper end. There's a similar piece on the next link down that moves, but it doesn't have a spring. All the other parts that come in contact with the rope appear to be fixed rigidly to the rivets that hold the chain together.

Mine has SN 19F019... It was purchased new in 2019. The one in the report has SN 18d013...

I can't wait to see the full explanation from Petzl.
For reference sake, Your zz was made in June of 2019. The first two numbers are the year the letter corresponds with the month A is Jan B is Feb...

Tony
 

JeffGu

Well-Known Member
Yes, for Version 3 units. The older, Version 2 ones have a similar format:

14057ON6237

Where the date is numeric... 2014, May 7th in this case.
 

Winchman

Active Member
JeffGu in post 11 confirms what I found in examining my own ZZ: The only spring is in the release lever at the top of the chain.

The spring there is not very strong, and I suspect it's possible the ZZ would work on some larger ropes from friction alone without the spring.

I've had the ZZ fail to engage while climbing through foliage when something presses on the release lever. I've also had it let me fall a short distance when some foliage I moved hit the release lever. The ZZ is lightly loaded in a 3:1, so the release is very sensitive. I haven't let these events shake my trust in the ZZ.

I'd like to know what kind of rope was being used with the ZZ that supposedly failed.
 

Chaplain242

Well-Known Member
Agreed the pic was mislabelled and not a good pic, but the report may still have credence in that it let go causing freefall... I would suspect that the report writer has little idea how device works, but again will wait till report comes out.

But if the top spring did break that would be worth knowing about if using zigzags, as may be a safety measure to use upper range of suitable rope size...
 
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